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1. User Input gt Userinterface gemma User Feedback C L Safety System L3 DisplacementSensing Figure 29 Implementation of Displacement Sensing Control Hardware The hardware used fig 30 comprises a PC a STK500 Evaluation Board fig 31 32 see also chapter 5 2 1 and a Twin Eye Laser Sensor fig 37 see also chapter 5 1 1 The PC is used to develop software using AVR Studio chapter 6 1 2 step 1 and download it to the ATmega8515L microcontroller see chapter 5 2 mounted on the STK500 Evaluation Board 60 Koninklijke Philips Electronics N V 2009 Unclassified PR TN 2009 00597 PC lt lt Rpm clerics AVR Studio board Twin Eye Laser Sensor Figure 30 Block diagram of hardware used to implement Displacement Sensing Fal gt pi FW WE oe oe ae et ee ee te T1 En PI ETUDIEZINJS mx piri bi F iiir Patij WERA ALI EH ope on pp EH Nd HH EG LEERDE Mt er rts JE EE DATAFLASH e 381A RI a ba gt 11 h LS Tot ts i mE pE a fii g I at ANG PLP aa e T er pes 2 di HESS LATA kal m m i la EWEEK Figure 31 STK500 Evaluation Board Fig 32 shows the overview of the STK500 Koninklijke Philips Electronics N V 2009 61 PR TN 2009 00597 Unclassified Header for derd 7 Sockets for Expansion Boards Target AVR Options Setting Target Reset Jumpers Fush Button Switches i 7 a Power Switch 5 MEH HH
2. 76 Koninklijke Philips Electronics N V 2009 Unclassified PR TN 2009 00597 CPOL is set to zero This is the clock polarity configuration 21 CPHA high is the phase selection bit used to determine the data transfer sequence on the SPI Bus Setting this bit to one enables data transmission on the trailing edge of the clock signal Combining of CPOL and CPHA four differ ent modes of operation see data sheet 21 are defined SPR1 and SPRO set the clock frequency These two bits together with SPI2X described in SPSR register configuration configure the clock frequency for SPI operated slave devices 21 SPRO and SPI2X are set to one and SPR1 is set to zero This setting makes the SPI Bus to run at a frequency 8 times slower than the oscillator frequency which is 3 86 MHz 21 SPSR is the SPI status register Table 7 SPI status register SPSH 21 PEN 1 SPIF is the SPI interrupt flag It is set high when the serial transfer is completed This means when data transfer is finished this flag will become high and this will run the interrupt routine if the SPIE flag is set in the SPCR register This flag is also cleared on reading transferred data In our case the SPIE flag is not set in the SPCR register WCOL is the write collision flag which will be set high if the data is written dur ing transferring of data 21 SPI2X is double the SPI speed bit If this bit is set to one then it will double the clock fr
3. controller will acknowledge the completion of the capacitor charging by detect ing active low indication from the flash on the pin D2 The trigger signal is given by the microcontroller to the flash from the pin D4 Safety module Saftey means that flashes are only released when the pho toepilation device is in contact with the skin 1 The Twin Eye Laser Sensor works only if it is at a particular distance range of 2 3 0 8mm from the surface If the distance from the surface is not within this limit the sensor will not function Therefore receiving valid data from the sensor indicates that the sensor is in contact with the skin 2 A separate switch can be used to determine contact between the photoepila tion device and the skin one of the switches of the STK500 module is con nected to the microcontroller as input is used to mimic this The safety condition is indicated by one of the LEDs of the STK500 board The idea is that the safety switch will be mounted on the front of the device next to the flash emitting window In the implementation the sensor gives displacement reading only if the safety switch is pressed and the flash is only triggered if both safety condi tions are satisfied Pin D5 is an input signal to the microcontroller from the switch one of the switches of the STK500 here referred to as the safety switch Whenever this switch is pressed the LED connected to the pin D6 will glow indicating that the safet
4. 2009 00597 18 Gunther Gridling and Bettina Weiss PDF downloaded from http ti tuwien ac at ecs teaching courses mclu theory material Microcontroller pdf Introduction to Microcontrollers Version 1 4 19 PDF downloaded from the Atmel s webpage http www atmel com dyn resources prod documents doc2585 pdf Setup And Use of The SPI 20 PDF downloaded from the Atmel s webpage http www atmel com dyn resources prod documents doc1925 pdf AVR STK 500 User guide 21 Photos downloaded from the webpage http www aestheticmd com images clip image002 002 jpg 22 Photos downloaded from the PHILIPS webpage http www philips es shared assets es Promolmages N SC2000 ipg 23 Photos downloaded from the webpage http www uvabcs com images ultra visible jpg 24 Photo downloaded from the webpage http www aesthetic lumenis com pdf laser principles aspects pdf 25 Photo downloaded from the webpage http thornhillskinclinic com blog wp content uploads 2009 06 laser hair removal jpg 26 Photo downloaded from the webpage http 4 bp blogspot com OxiGGXx4sdE SHNfDvnYcrl AAAAAAAAABC 8GvK9KXBVDLA s400 350 px Illu skinO2 jpg 27 Photo downloaded from the webpage http virtuallaboratory colorado edu Biofundamentals lectureNotes AllGraphics epidermal 20Ste m 20cells gif 28 Discussion with B Ackermann 2009 Koninklijke Philips Electronics N V 2009 107 PR TN 2009 00597 Unclassified Figures Figu
5. Complications are rare if treatments are done carefully and with the patient s skin type in mind 2 Limitations 1 Multiple treatment sessions are required to achieve the maximal level of hair reduction 2 Some patients with light skin colour and finer hair can have re growth of hair 3 It is not suitable for patient with skin disease Side Effects Some temporary or permanent side effects can occur using any light source based hair removal treatment 1 Laser hair removal is not a painless procedure This depends on the flu ence rate and skin type 2 Epidermal damage occurs if excessive fluencies are used 3 The most common side effects are transient pigmentary changes such as hypopigmentation or hyperpigmentation It can be prevented if the appro priate treatment fluencies are chosen for a certain skin type 4 Retinal injury can happen if proper eye protection is not provided Koninklijke Philips Electronics N V 2009 29 4 1 PR TN 2009 00597 Unclassified Consumer Device Concepts Point of Care and Home Applications Usability Safety Nowadays medical and cosmetic consumer devices are becoming part of the daily life of people New technologies aim at satisfying requirements with re spect to comfort and safety These technologies make use of scientific results obtained with and research aiming at professional systems The challenge is to develop small affordable devices that are powerful enough to
6. Electronics N V 2009 119
7. HT Header for i I AMEL A Fower Connector H Switches f H iy ex i li m AVR n zd _ BAI M Ol e Power LED I Hi gg i Parallel Programming YY i ee Headers C OB P RS 232 Interface IIO O l l l l l l l I I Header an RS 232 Port i 1 my g for Programming 6 Hi l T I i DataFlash r a i erm Pa Status LED ataFlash Interface po pisse lt I eder Pan ET A s 230 Pon i H i E im e for Communication l so 1M ee EL nip ICI des e Header for LEDs l 3 Crystal 1 mH HHL Ht Program Button LEDs 10 pin IBP Header Header for for External Target Only Target ISP Headers Expansion Boards amp pin ISP Header ATmegaG5i5_ Microcontroller Socket Figure 32 STK500 overview 20 The power supply power connector power LEDs and RS 232 Port are located on the upper right side of the board A 12V STK500 voltage range 10 to 15V 500mA power supply is used 20 and the RS 232 Port is connected to the computer as shown in fig 33 Figure 33 Power supply and RS 232 connection between STK500 and computer 20 62 Koninklijke Philips Electronics N V 2009 Unclassified PR TN 2009 00597 There are 8 jumpers fig 34 set for configuring the board 20 These jumpers are set as follows ee ee ee ee em am B D IT o a I un m LH un m r Pa B a c 5 i nnn e ee nnn ee Figure 34
8. When the XTAL1 jumper is not mounted then an external clock source or crystal can be connected to the Port E header see datasheet OSCSEL on board oscillator selected There are two possibilities to supply a clock signal to the XTAL1 and so to the target microcontroller i e either con trolled by software or from an on board crystal clock The software controlled clock range is 0 3 68MHz and the crystal clock range is 2 20MHz In order to select the internal software clock signal the OSCSEL has to be mounted on pins 1 and 2 as shown in fig 35 BSEL2 has to be open It is used for High Voltage Programming In our setup programming is done using In System Programming PJUMP has to be open It is used for High Voltage Programming 64 Koninklijke Philips Electronics N V 2009 Unclassified PR TN 2009 00597 The STK500 is delivered with a 6 wire cable that is used for In System Pro gramming of the target microcontroller SS PB2 PB3 MOSI MISO PB4 PB5 SCK PB6 PB7 VTG Alternate Function Figure 36 STK500 6 wire cable In System programming and Port B alternate functions The ATmega8515L microcontroller is mounted on the 40pin socket as shown in fig 36 it has 4 I O Ports Most ports have alternate functions in addition to gen eral I O In the ATmega8515L Port B has Serial Peripheral Interface SPI see chapter 5 1 2 as alternate function 21 Koninklijke Philips Electronics N V 2009 65 PR TN 2
9. also cells in the hair follicle which are not pigmented called stem cells no melanin in these cells shown in fig 3 These cells lie at the outer root area called bulge near the attachment of the arrector pili muscle some distance from the pigmented area These cells are essential for the hair growth cycle 27 stem cells matrix rol over Figure 3 Stem cells 27 12 Koninklijke Philips Electronics N V 2009 Unclassified PR TN 2009 00597 Hair Growth Cycle Traditionally there are mainly three phases of the hair growth cycle recognized Anagen phase It is an actively growing phase The papilla is connected with the blood vessels Cells in the matrix are divided and grow upward to form the hair shaft Depending on the location this phase may last for several years 2 Catagen phase Once a hair reaches its full length cell division and pigmenta tion stops The hair becomes fully keratinised with a swollen club end and moves up towards the outer layer of the skin and rests there This phase is called the catagen phase 2 Telogen phase After a short rest period the dermal papilla cells and keratino cyte stem cells become active again and a new hair grows from the new follicle The old hair gradually gets lost from the surface This phase is called the te logen phase 2 Recent research suggests that shedding of the hair fibre is an active process and introduce the new term exogen for this phase After
10. are a couple of programs available in which one can write a program and then load it into the microcontroller 56 Koninklijke Philips Electronics N V 2009 Unclassified PR TN 2009 00597 AVR Studio is used for this project This software is also used for debugging for simulating the program in the PC and for downloading programs into the microcontrollers memory This is described in detail in chapter 6 The Atmel ATmega8515L 8 bit RISC microcontroller mounted on the STK500 Evaluation Board was used for this project 5 2 1 STK500 Evaluation Board u A z cd Figure 26 the STK500 Evaluation Board 20 The STK500 Evaluation Board has 8 LEDs 8 push buttons two RS232 Ports for programming and control and an on board frequency generator It provides easy access to the Atmel microcontrollers including the Atmega8515L It has extended microcontroller s O Ports Koninklijke Philips Electronics N V 2009 57 5 3 PR TN 2009 00597 Unclassified In System Programming is used for programming the microcontroller ISP re quires 6 wires i e Vcc GND Reset and three signal lines for programming 20 Configuration of the board connections and operations are described in chapter 6 Test Bench A mechanical setup was designed and built for testing the displacement sen sor s functionality Fig 27 shows the mechanical setup comprising motor rotor sensor housing and position adjuster flash housing and position adj
11. be effective but safe enough to be used by consumers 5 okin care and hair care products attract a lot of attention both by people and by companies Many people spend countless hours per week in the shower shav ing and cutting themselves in a relentless pursuit of hairless skin that is smooth to touch or spend series of sessions at clinics or spas to treat a particular area of the skin even though it costs huge professional fees 5 Professional cosmetic instruments are usually complicated to use mostly be cause they are designed to operate in various conditions with selection of vari ous parameters They are only allowed to be operated by qualified persons Before the treatment the treatment area is examined and then possible benefits and the side effects are considered These treatments last over longer periods Various sessions are necessary to obtain the expected result This is not af fordable in terms of cost and time for all people In contrast home use devices are made for dedicated use and suitable for a particular range of people They have limited parameters to adjust One can do the treatment as described in the user manual on a convenient time Treatment effects safety features warnings and side effects are described in the user manual It is only one time cost ex penditure except that some accessories may need to be changed Since recently several companies are releasing light based hair removing con sumer devic
12. define AVRGCC include lt avr io h gt include C sensorprogram6 config h include C sensorprogram6 mouse_wired_philips_drv h include C sensorprogram6 TwinEye_api h define Sensor_report_reset Sensor report 0 0 Sensor_report 1 0 Sensor report 2 0 Sensor report 3 0 Sensor report 4 0 Sensor report 5 0 unsigned int DisplacementX LEDs deltaX stored DisplacementY LEDs deltaY stored volatile U8 Sensor report 6 define SPI INT 1 PORTD2 use only if SPI interrupt mode define SPI CS 1 lt lt PORTB4 Cheap Select define SPI SCK 1 lt lt PORTB7 Clock define SPI MISO 0 PORTBO MISO define SPI MOSI 1 PORTB5 MOSI Master Controller Configuration void sensor configuration Master SPI Configuration Master Thesis 6 1 2 Step 2 SPI DDR SPI CS SPI SCKJ SPI MISO SPI MOSI SPI PORT SPI CS DDRD SPI INT SPCR 1 lt lt SPE 1 MSTR 1 lt lt CPHA 1 SPR0 SPSR 1 lt lt SPI2X Master output Configuration DDRC OxFF Display LEDs DDRA OxFF Display LEDs MITT Sensor MHI bit Sensor_event Sensor report reset reset refer Master Thesis 6 1 2 Step 4 TwinEye report read the sensor if g fTwinEyeReport 1 TwinEye report read cycle finished 112 Koninklijke Philips Electronics N V 2009 Unclassified PR TN 2009 00597 g fTwinEyeReport 0 TwinEye report can be read in ne
13. is Displacement Sensing This is a key module of the Track and Flash concept This module affects the device s safety module feedback module and the functionality of the flash All together it increases the complexity of the control The Displacement Sensing module is introduced to measure displacement of the device while moving on the skin Displacement Sensing can be done by l Mechanical technology II Optical image processing technology III Laser self mixing technology Mechanical technology can sense movements using moving parts Tracking can be achieved in many ways for example using a computer mouse with a roller ball The mechanism with roller ball rotates x and y axis gears in x and y direction respectively and gives displacement with reference to a previous place This simple roller ball mechanism can be selected as Displacement Sensing module on the skin which gradually moves along on the skin and at tach to it an encoder used in motors for counting the number of rotations This way one can give user feedback in terms of distance or area treated until now In principle mechanical way of tracking should work but this would make the Figure 15 Mechanical technology 38 Koninklijke Philips Electronics N V 2009 Unclassified PR TN 2009 00597 device bulky and may be less accurate In the case of a roller ball used as a tracking device the roller ball needs some projected area which comes in sur face contact and in
14. light UV and IR They convert major energy into light instead of heat and they can be operated in pulse mode This is suitable for hair removing applica tion Solid state light sources LEDs cannot generate enough intensity needed 26 Koninklijke Philips Electronics N V 2009 Unclassified PR TN 2009 00597 for hair removal application but lasers can be used for hair removal application Lasers generate parallel light which has a focused beam and which can also be generated in pulse form Laser produces a single wavelength Lasers with wavelength between 600nm to 1100nm are suitable for hair removal applica tion The major light sources Lasers and IPL used for hair removal are shown in the Table 1 Skin type Table 2 hair colour and hair diameter are mainly taken into consideration for the selection of the light source According to Table 2 The Q switched Nd YAG and the Intense Pulsed Light source are suitable for all skin types and dark to light brown hair colour Ruby Alexandrite pulsed diode Nd YAG lasers and intense pulsed light sources can provide hair removal We consider Intense Pulsed Light sources for hair removing device All light sources suited for photoepilation emit a single wavelength except Intense Pulsed Light source which is producing visible light UV and IR wavelength of electromagnetic spectrum It is an advantage of Intense Pulsed Light sources that using filters they can cover the optimum absorption
15. light is projected on the surface and reflected light is detected Interference between laser light and reflected light is evaluated In result it gives movement with respect to previous position Philips Lighting Laser Sensors is offering sensing devices using this technology named Twin Eye Laser Sensor 12 laser amp detectar siens Reflecting object Figure 17 Laser self mixing technology 16 One of the major applications of this technology is in gaming mice This tech nology can also be one of the options for the displacement module for Track and Flash 40 Koninklijke Philips Electronics N V 2009 Unclassified PR TN 2009 00597 The operating function of both laser technology and image processing is the same If we compare only light illuminating source laser diode and LED are used for sensing A laser emits coherent light It creates higher contrast on the reflected surface compared to LEDs If we use an image processor for calculat ing displacement for both laser and LED then a laser creates contrast providing 20 times improvement in result 11 Optical image processing and Laser self mixing technology are preferred for the Track and Flash application since they have no mechanical moving parts a flat surface are easy to clean accurate work on skin surface and are small in size Koninklijke Philips Electronics N V 2009 41 9 1 PR TN 2009 00597 Unclassified Key Components for Track and Flash Going
16. pin is selected as output and in the third step it is not necessary to set the clock Slave Initialization Configure MISO as output alla Set bit SPE of the SPCR reg atar Enable SPI Interrupt Clear SPI Inter rupt Flag by reading SPSR and SPDR Enable global Interrupts Flow Chart 4 Interrupt controlled Slave device flow chart 54 Koninklijke Philips Electronics N V 2009 Unclassified PR TN 2009 00597 5 2 Microcontroller An AVR microcontroller was used for implementing the Track and Flash con cept since software available for communicating with and controlling the Twin Eye Laser Sensor could be built upon The Twin Eye Laser Sensor communicates with the microcontroller using the SPI interface Furthermore the microcontroller has to be connected via digital I O Ports with the flash module a display for indicating displacement and switches for various controls An RS232 interface module is used for downloading a program to the microcon trollers memory Displacement i External Devices Sensor Computer RS 232 SPI Interface Interface Interface modules Digital Input Output module Internal Bus _ Processor Mn PWM Timer _ Core Memory Controller Generator Counter Figure 25 Microcontroller architecture and Interface devices 18 Koninklijke Philips Electronics N V 2009 55 PR TN 2009 00597 Unclassified The basic architecture of a microcon
17. quite recently or will be available soon For these it is a major challenge to reduce the time needed for treating large areas of the body like the legs Operating these devices in Track and Flash mode instead of Step and Flash mode can contribute significantly to achieving this goal In Track and Flash mode the device is tracked across the skin and flashes are released automatically at equal intervals In Step and Flash mode the device is placed on the skin a flash is released and these steps are repeated on adjacent spots on the skin Whilst the Track and Flash concept is well known hitherto no attempt has been made to actually implement it This report master thesis of Dipen Parikh describes the first steps taken towards implementing the Track and Flash concept A Philips Twin Eye Laser Sensor measures the motion of a rotating disk and this information is used to trigger commercially available flash lamp modules at equal intervals Conclusions The Philips Twin Eye Laser Sensor has been used successfully to realise a tracking system The functionality of the tracking system was tested and proven on the experimental setup and also on different surfaces The Track and Flash concept has been successfully introduced on the experimental setup Flashes are being triggered on predefined safe conditions and at fixed intervals based on the displacement being monitored by the sensor Although from observations it can be stated that flashe
18. that way the roller ball moves across the surface A me chanical or optical device can count the rotation The flashes also need to come into contact with the surface In that case flash and roller ball are located on the front part of the device and conflict the function of each other Secondly a roller will be less accurate and can make trouble on smaller area e g bikini areas because the surface is not flat enough Optical image processing technology is combination of electronic light source camera and image processor Figure 16 Electronic Optical sensing 10 Fig 16 11 shows the mechanism of electronic optical sensing A LED is used as a light source Light is projected on the surface reflected light is collected by optical lens and the camera takes a picture frame Several frames are cap tured fast enough so that sequential pictures overlap These frames are proc Koninklijke Philips Electronics N V 2009 39 PR TN 2009 00597 Unclassified essed by the image processor resulting in giving information about the move ment Avago Navigation Interface Devices 10 use this technology This technology is used in optical mice and it seems that it should work as a tracking module in the Track and Flash concept Laser self mixing technology uses a combination of laser and detector This technology works on the interference and phase shift principles Fig 17 12 shows laser reflecting object lens and detector Laser
19. where the absorption of haemoglobin and water are low However other lasers have also shown effective results e g alexandrite laser diode laser and Nd YAG laser Lasers generate a single wavelength whereas an Intense Pulsed Light source generates a complete spectrum of light Using appropriate filter wavelengths between 600nm to 1200nm can be filtered out from the flash lamp spectrum and can be used for the whole absorb ing region of the melanin 1 2 Not all of the light is absorbed by the hair melanin some energy is absorbed by the skin melanin also which may result in burning effect on the skin Dark skin has a high amount of melanin in the epidermis layer of the skin which gives highest burning effect The photoepilation method is facing a conflict between these two melanines Some cooling methods like cold air flow gel ice can minimize thermal injury of the epidermis layer 2 Selection of pulse duration Thermal transfer theory suggests that pulse duration of light targeted to melanin also plays an important role The follicular structures will get heated because of the thermal conduction from the melanin rich shaft and matrix Long pulse dura tion will generate more heat which also damages the surrounding tissue For damaging of just the hair follicle the pulse duration should be shorter or equal to the thermal relaxation time of the hair follicle For permanent hair destruction another type of cells is playing an important role
20. which are called the follicular stem cells discussed before in chapter 2 1 Anatomy of Hair To damage these stem cells the pulse duration should be greater than the thermal relaxation time i e in the region of thermal damage times The light absorbed by the melanin present in the hair root generates also heat This heat will propagate through the entire volume of the hair to better damage the stem cells 2 Koninklijke Philips Electronics N V 2009 21 PR TN 2009 00597 Unclassified Selection of Fluence Fluence is playing an important role for long term hair removal As discussed previously in chapter 2 1 Anatomy of Hair a fluence less than 10J cm cannot create enough heat to damage the hair follicle strongly Fluences above 20 J cm damage the hair follicle strongly resulting in permanent hair loss Careful studies with computerized hair counts have demonstrated that greater hair loss is achieved at the higher fluences tested 2 However the skin type and the colour of the hair are major factors in determining a suitable fluence A higher fluence will give more burning effect on the skin surface Dark black skin has a large amount of melanin present in the skin This will give more burning effect on the skin surface than with the fair skin 22 Koninklijke Philips Electronics N V 2009 3 5 Unclassified PR TN 2009 00597 Light Sources Light is electromagnetic radiation in the UV visible and NIR region of the elec trom
21. 009 00597 Unclassified Table 3 ATmega8515L Port B pin alternate functions 21 Port B Pins Function Remark PB7 PB6 PB5 PB4 PB3 PB2 PB1 PBO SCK MISO MOSI SS AIN1 AINO T1 TO OCO SPI Bus Serial Clock SPI Bus Master Input Slave Output SPI Bus Master Output Slave Input SPI Slave Select Input Analog Comparator Negative Input Analog Comparator Positive Input Timer Counter1 External Counter Input Timer CounterO External Counter Input Timer CounterO Output Compare Match Output Configurations of these pins are discussed in the software part Twin Eye Laser Sensor pin information and its connection with the microcontroller This sensor has 11 leads Their functions are described below Table 2 The pin CSn Pin5 in the sensor and the SS pin PB4 in the microcontroller have the same function but are named differently 66 Koninklijke Philips Electronics N V 2009 Unclassified Table 4 Twin Eye Laser Sensor pin functions 15 PR TN 2009 00597 Pint Pin2 Pins Pin4 Pind Pin6 Pin7 Pin8 Pin9 Pin10 Pin11 Reserved VDD GND Decoupling CSn CLK MISO MOSI Interrupt XIAI P XTAL N Koninklijke Philips Electronics N V 2009 Not in Use 3 3V Supply voltage Ground Internally connected with capacitor mounted on PCB SPI Chip Select pin Slave device selection pin SP
22. 2m 4 mV DE L numo Figure 47 valid bit high data are valid The output from the sensor is displayed in terms of counts on the LEDs of the microcontroller board 84 Koninklijke Philips Electronics N V 2009 Unclassified PR TN 2009 00597 Results This setup was used to validate that the sensor works on a range of surfaces The Twin Eye Laser Sensor was powered up and its initialisation routines were executed successtully The SPI bus settings were validated by establishing successful communication between sensor and microcontroller Data transfer routines were also tested and validated by reading data sampled by the sensor This data was interpreted with the help of blinking LED patterns Laminate surface This laminate surface has a slightly rough surface The functionality of the sensor on the laminated surface was validated by the results of the test conducted on the surface This hand moving sensor experiment shows that if the sensor is moving in one direction the LED pattern is increasing counts If the speed of the motion of the sensor is increased the LEDs are updating fast If the sensor is moved in the reverse direction of the before movement the LEDs counts are decreasing Figure 48 Sensor tested on laminate surface Koninklijke Philips Electronics N V 2009 85 PR TN 2009 00597 Unclassified Smooth glossy white surface Even when tested on surfaces with high smoothness the sensor delivered functionality and LE
23. 7 Unclassified Selective Photothermolysis The principle of selective photothermolysis comprises that by choosing appro priate wavelength pulse duration and fluence thermal injury can be confined to a target chromophore 2 Selective photothermolysis provides a thermal dam age to the target with minimum disturbance of the surrounding tissue Wavelength The wavelength of the electromagnetic radiation has to be se lected to provide maximum contrast of absorption of the target vs the surround ing tissue and other competitive targets 1 In the human body natural chromophores are present The most important chromophores in the skin are melanin haemoglobin and water Melanin is present in the epidermis layer of the skin in the hair root and in the hair shaft Haemoglobin and water are distributed in all the tissue mostly at every layer These chromophores have different bands of absorption as shown in fig 5 Diode 800 nm Alexandrite 755 nm Ruby 694 nm i JN LON Nd YAG 1064 nm Absorption log scale mi dU 300 500 700 1000 2000 Wavelength nm Figure 5 Relative absorption of melanin blood and water 24 18 Koninklijke Philips Electronics N V 2009 3 4 Unclassified PR TN 2009 00597 Oxyhaemoglobin absorbs light mainly at shorter wavelengths between 300nm and 650nm with peak absorption between 400nm to 450nm Water absorbs light mainly at longer wavelengths above about 1000nm with peak ab
24. D patterns as shown be fore for the laminate surface Figure 49 Sensor tested on smooth glossy white surface Translucent surface The material shown in the fig 50 is transparent but a coated layer creates a translucent effect to the material properties While mov ing the sensor on this partially reflective surface it was not able to detect dis placement Figure 50 Sensor tested on translucent suface 86 Koninklijke Philips Electronics N V 2009 Unclassified PR TN 2009 00597 Mirror surface As discussed before in chapter 5 1 1 for the sensor to deliver a signal it is imperative to receive a partially reflected light beam This phe nomenon ideally should not occur when tested on the perfect mirror like surface because the light received in this case would be perfectly reflected instead of being scattered But due to the deposition of dust particles a portion of the light is always scattered therefore the sensor operates with the desired effect on a mirror like surface bea T al te MA Figure 51 Sensor tested on the mirror Skin Skin has absorbing reflecting and scattering properties Therefore the sensor works on skin Figure 52 Sensor tested on the skin Koninklijke Philips Electronics N V 2009 87 PR TN 2009 00597 Unclassified 6 2 Displacement Sensing in the Mechanical Setup Implementation 2 The aim of these experiments is to check quantitatively the functionality of the Twin Eye Las
25. I Clock Supply by Master SPI master in slave out SPI master out slave in Interrupt output Oscillator input Oscillator output 67 PR TN 2009 00597 Unclassified Philips Lighting Laser Sensors has provided a PCB for mounting the Twin Eye Laser Sensor Crystal clock generator components were mounted on the PCB Output of that becomes input for the sensor at Pin10 and Pin11 see table 2 The sensor is mounted on the PCB as shown in fig 37 Twin eye laser sensor PCB back view connecting port Twin eye laser sensor mounted on PCB Figure 37 Twin Eye Laser Sensor mounted on PCB This PCB has 8 pins out of these 4 pins SPI pins are connected to the micro controller and the other two are connected to the power supply and the ground The remaining 2 pins have no function for this project As discussed before the Twin Eye Laser Sensor has to maintain typically 2 3 mm distance from the surface for its proper performance So the sensor was mounted in a specially fabricated housing shown below which maintains this distance 68 Koninklijke Philips Electronics N V 2009 Unclassified PR TN 2009 00597 Figure 38 Back view of PCB connecting port details A bridge circuit was made to connect the sensor with the microcontroller board and the power supply refer fig 39 Koninklijke Philips Electronics N V 2009 69 PR TN 2009 00597 Unclassified SS PB2 MISO PB4 PB6 GND Figure 39 Connection betwee
26. Internat CAARG MGE sadi ope eaDrcowi a aa 93 Figure 61 Mechanical setup with Hamamatsu flash lamp module 94 Figure 62 Connection between sensor microcontroller power supply and Hamamatsu flash lamp glee 94 Figure 63 Pulse Width MOAUAONnstverrrenesnser sedert sanne as ocu Eu auae exte senen ups eus veren RE D EsUsR vds 96 Figure 64 Implementation of Track and Flash using TI Evaluation Module 98 Figure 66 Blcok diagram of setup 2 ann eaneennnenvennenrennnrnrvennnnnvenanenvennneereennnenvennnerennnenn 99 Figure 65 Texas Instruments evaluation module anssen ennennnneeneenenenenreennnneerr nennen 99 Figure 67 EXPermental SSUP rn ererstedere geborene eenden vonden nternet neen enden den 100 Figure 68 connection between sensor microcontroller power supply and TI Evaluation Module ptu LM LLL Mi Tu ERE LC I 100 Koninklijke Philips Electronics N V 2009 109 PR TN 2009 00597 Unclassified Tables Table 1 Indications and expected efficacy for different hair removal devices 2 27 Table 2 Skin type and Colour 2 Iwein ereen 28 Table 3 ATmega8515L Port B pin alternate functions 21 eeeeeeseessssssssss 66 Table 4 Twin Eye Laser Sensor pin functions 15 oenen ennn eeeennnnne enne eeennnnnneennne evens 67 Table 5 Master and Slave pin configuration 21 15 nennen ennnnnennrennnnnenvens 76 TADEG SPI Oonm
27. MH T T ITI WM Sentence J Eos MM Mil MEL 2450 peint a Toup OFF ET Loose 771 34 em division J B 10 20 50 pkph C2 28 wv ane meant 15 8 nV sent 2 2 5 mv rnsid 15 7 mV 20 pc anol 2 Jt Zi mv 1 5 v DC 2 1 V DC LOB MS s El v DC f a 2 DC 270mV 4 2nmV Uf BL TO Figure 45 SPI data bytes Koninklijke Philips Electronics N V 2009 81 PR TN 2009 00597 Unclassified 27 0 H HARDCOPY fe 26 ps TAH pal c my LIL BITE Figure 46 Data trasmittion on the MISO line Is valid bit high and motion bit high The Status register contains bits that indicate 1 whether the sensor has moved since it has been read last and 2 whether there are valid data in the deltaX and deltaY registers When the valid bit and the motion bit are both high the data in the deltaX and deltaY registers are considered as valid data Store deltaX and deltaY registers After receiving valid data from deltaX and deltaY from the sensor registers these data are stored in the 16bit register defined in the microcontroller to contain total displacement On every reading new data coming from the sensor register are added to this register 82 Koninklijke Philips Electronics N V 2009 Unclassified PR TN 2009 00597 De Select Sensor CSn high This will disconnect the sensor from the micro controller The SPI clock will stop as shown in the fig 44 On the deselecting edge of the clock the sens
28. PI interface the master can read data from the slave in two ways 19 I SPI communication controlled by polling I SPI communication controlled by interrupts The microcontroller ports are designed to serve more than one function They have to be enabled and configured via programming The SPI function is acti vated by enabling the SPE SPI Enable bit in the SPCR register 17 19 The SPI Control Register SPCR and SPI Status Register SPSR play a major role Flow charts shows master and slave device configuration For SPI communica tion control by polling and interrupts are discussed in the following SPI Communication Controlled by Polling This is mainly used for communicating with a slave device which is updating frequently The master device reads data from a device or multiple devices at fixed intervals Koninklijke Philips Electronics N V 2009 49 PR TN 2009 00597 Unclassified Master Initialization Configure SS MOSI and SCK as output pins Set bit SPE and MSTR of the SPCR register Clear SPI Interrupt Flag by reading SPSR and SPDR Return Flow Chart 1 Polling mode Master device configuration flow chart Flow chart 1 shows the master device configuration in polling mode SPI com munication The SS MOSI and SCK pins are set as output pins otherwise the device would be configured in slave mode After this step SPE and MSTR are enabled MSTR is the master MSTR high or slave MSTR low selectio
29. STK500 jumper settings 20 VTARGET has to be short This means that the on board supply voltage is connected The voltage level can be adjusted between 0 6 V by software chap ter 5 1 2 step 1 The voltage has to be set to 3 3V to agree with the voltage used by the Twin Eye Laser Sensor If an external power supply is used then this jumper has to be open 20 AREF has to be short This will connect the reference voltage to the on board supply voltage This voltage can be controlled by software chapter 5 1 2 step 1 It should be less than VI ARGET If an external reference is used then this jumper has to be open RESET has to be short While programming the selected microcontroller if this jumper is short then the reset pin is controlled by the master programming de vice here the STK500 internal microcontroller is a master programming de vice If it is open then external RESET should be connected Koninklijke Philips Electronics N V 2009 63 PR TN 2009 00597 Unclassified Jumper mounted on pins 1 and 2 I XTAL4 Tae m I I C I OSCSEL r On board software clock signal connected i Jumper mounted on pins 2 and 3 l I l I on _ l I I l OSCSEL 5 On board crystal signal connected Figure 35 XTAL1 and OSCSEL jumper setting XTAL1 has to be short This means that the on board clock system is con nected to the target microcontroller The source of the clock is determined by the OSCSEL jumper
30. Technical Note PR IN 2009 0059 7 Issued 11 2009 Track and Flash for Photoepilation Using Optical Displacement Sensing Dipen Parikh B Ackermann Philips Research Europe Unclassified Koninklijke Philips Electronics N V 2009 PR TN 2009 00597 Unclassified Authors address Dipen Parikh Dipen Parikh philips com B Ackermann bernd ackermann philips com KONINKLIJKE PHILIPS ELECTRONICS NV 2009 All rights reserved Reproduction or dissemination in whole or in part is prohibited without the prior written consent of the copyright holder ii Koninklijke Philips Electronics N V 2009 Unclassified Title Author s Reviewer s Technical Note Additional Numbers Subcategory Project Customer Keywords Track and Flash for Photoepilation Using Sensing Dipen Parikh B Ackermann IPS Facilities PR TN 2009 00597 Male Body Grooming 2008 041 Photonic Therapy 2004 347 CL Shaving amp Beauty PR TN 2009 00597 Optical Displacement photoepilation Step and Flash Track and Flash displacement measurement opti cal tracking optical sensors self mixing interference image processing Koninklijke Philips Electronics N V 2009 iii PR TN 2009 00597 Unclassified Abstract Light based hair removal photoepilation has been applied by dermatologists and in beauty parlours since more than a decade A few photoepilation devices for at home use have been commercialized
31. agnetic spectrum Visible light ranges between 400nm to 800nm starting from violet to the red Light that is more violet than violet called ultraviolet light UV ranges from 10nm to 400nm and light redder than red is called infrared light IR in the range between 800nm to 3000nm 23 UV UV UV VISIBLE EIGHT INFRARED C B A 290 320 400 Wavelenghs in nm T60 Figure 6 Visible light spectrum 23 Generation of light can be natural or men made Light sources can be catego rsed as incandescent gas discharge and solid state An incandescent source is an object heated so much that it gives off light It can be described theoretically as a black body which emits different radiation as its temperature increases A gas discharge source uses electrodes and gas to generate light Intensity and colour of the light emitted by the source depend on the type of gas used and the pressure of the gas in the tube A solid state source is built en tirely from solid materials and generates light electronically These solid materi als are semiconductors and the colour of the light emitted from solid state de pends on the type of semiconductor used Koninklijke Philips Electronics N V 2009 23 3000 PR TN 2009 00597 Unclassified Incandescent means giving off light as a result of being heated The sun is a natural source of incandescent light The sun emits light because of a very slow reaction in which hydrogen burns to helium Man made incandescent lig
32. agram of hardware used to implement Displacement Sensing 61 Figure 32 STISS00 Ove Mew 20 rsr cr FL ROO ex axi cn EA 62 Figure 33 Power supply and RS 232 connection between STK500 and computer 20 62 Figure 34 STK500 jumper settings 20 uannn ennn ennnnnenreeennnens vennen vennnnnensvennnns 63 Figure 35 XTAL1 and OSCSEL jumper setting unne a a e 64 Figure 36 STK500 6 wire cable In System programming and Port B alternate functions 65 Figure 37 Twin Eye Laser Sensor mounted ON PCB unne eenennnnneernneeennnnneerneeeeennnnens 68 Figure 38 Back view of PCB connecting port details nnnnnnnnnoennn neen ennneenneneenennnen 69 Figure 39 Connection between sensor microcontroller and power supply 70 Figure 40 AVR Studio interface for setting STK500 configuration sssessssssss 71 Figure 41 Program configuration in AVR Studio sanne ennneennnnenn renners eennneens vennen 73 Figure 42 Fuses settings in AVR Studio sees 73 Figure 43 HW settings in AVR Studio an sneseananer eer ensmnrnerensnreenreonnerenvennnenrendeonn 74 Figure 44 Slave select SPE CloCk uci e iie itu ta i oe eis data Set ie icu areae ated QI uv oues 80 Figure A SOP Cala DY LES titer idet i ortas dela Grat dete t oret s nen rur ease dads 81 Figure 46 Data trasmittion on the MISO line unssnnns enne ee
33. an integral part of the cosmetic field for a long time Many methods have been developed for re moval of unwanted hair shaving waxing mechanical method plucking and quite recently light based hair removal Especially light based hair removal depends on the anatomical features of hair and the hair growth cycle These are revieved and an overview of methods to remove hair is given in chapter 2 In the modern world where time and comfort are of essence light based hair removal photoepilation not only offers several distinct advantages over its less sophisticated and sometimes painful mechanical counterparts but also offers a long term solution to the user The working principle and some other aspects of photoepilation are described in chapter 3 Presently these light based technologies are used mainly in professional cos metic instruments These instruments are usually complicated to use mostly because their operation depends on various conditions and parameters such as skin colour energy intensity used in the treatment duration of treatment etc These instruments are only allowed to be operated by qualified individuals In contrast consumer devices are made for dedicated use and are suitable for a particular group of people They have limited parameters to adjust All existing light based hair removal devices are operated based on the Step and Flash principle which is time consuming because the entire area of the skin under tre
34. as shown in the flow chart 9 Koninklijke Philips Electronics N V 2009 103 PR TN 2009 00597 Unclassified 6 4 3 Results The implementation of the Track and Flash concept with the safety conditions shows the desired functionality only on receiving the feedback from the safety switch and the flash is triggered only after verifying safety conditions and when the preset distance was travelled by the sensor However the energy emitted by the flash is still not enough to heat up the rotat ing disk of the mechanical setup such that it can be seen by the thermal cam era 104 Koninklijke Philips Electronics N V 2009 Unclassified PR TN 2009 00597 Conclusions and Outlook The Philips Twin Eye Laser Sensor has been used successfully to realise a tracking system The functionality of the tracking system was tested and proven on the experimental setup and also on different surfaces The Track and Flash concept has been successfully introduced on the experi mental setup flashes are being triggered on predefined safe conditions and at fixed intervals based on the displacements being monitored by the sensor Although from observations it can be stated that flashes are being generated at equal distances travelled by the sensor due to the limited energy generated by the flash modules available the overlapping of flashes could not be validated with the means of a thermal camera Therefore the most important next step would be to mak
35. atasheets this slave device accepts input low voltage between 0 5 to 0 3 VDD and input high voltage between 0 7 VDD to VDD 0 5 where VDD is 3 3V 20 The micro controller has to communicate using this voltage level The microcontroller output voltage for communication with the Twin Eye Laser Sensor can be set in this HW settings section 3 5 V target voltage and 3 3V reference voltage is set The reference voltage should be less than the target voltage and it is used as reference in ADC see STK500 user quide for details STK500 in ISP mode with ATmega 515 7 Ioj x Main Program Fuses LockBits Advanced H Settings Hw Infa Auto Voltages WT arget Black Generator 3 606 MHz 3686400 Head al ike Cirman ara learn Figure 43 HW settings in AVR Studio 74 Koninklijke Philips Electronics N V 2009 Unclassified PR TN 2009 00597 Step 2 SPI configurations There are two ways of SPI communication i SPI communication controlled by polling ii SPI communication controlled by interrupts described in chapter 5 1 2 The SPI communication controlled by polling mode is used in this project as recommended and described in the Twin Eye Laser Sensor datasheet Flow chart 2 shows SPI configuration SPI initialisation Master and Slave pin directions SPCR register SPI configuration configuration SPSR register configuration Flow Chart 6 SPI configuration Master and Slave
36. atment has to be covered with flashes which can be generated one at a time On the other hand the Track and Flash concept involves automatic generation 8 Koninklijke Philips Electronics N V 2009 Unclassified PR TN 2009 00597 of flashes at fixed displacement intervals during the treatment Both Step and Flash and Track and Flash techniques are discussed in chapter 4 Chapter 5 deals with the technical requirements of the system and based on these requirements selection of the key components for implementing the Track and Flash concept This chapter deals also with the interfacing protocols between the selected components and provides an overview of the mechanical experimental setup The hardware and software of four different implementations used to validate the Track and Flash concept are explained in detail in chapter 6 and results obtained are discussed Koninklijke Philips Electronics N V 2009 9 2 1 PR TN 2009 00597 Unclassified Hair Removal Anatomy of Hair We have two types of hair on our body the vellus hair and the terminal hair Vellus hair is soft fine and short It is nearly unnoticeable but in some men or women it can be darker and noticeable This hair helps the body to maintain the body temperature by providing insulation The terminal hair grows on the head the armpits and the pubic region It is coarse longer and darker than the vellus hair Men have terminal hair on chest and back Terminal hair i
37. ay on LEDs PORTC LSB DisplacementX LEDs LSB display PORTA MSB DisplacementX LEDs MSB display trigger signal for Hamamastu Flash refer flow chart no 8 if DisplacementX_LEDs 0x007F predefine count distance travelled by sensor unsigned int time1 time2 time3 DDRD OxFF Delay for Turn on and Turn off time of PWM trigger signal Master Thesis 6 3 2 trigger signal for time1 0 time1 lt OxFFFF time1 if time1 lt Ox07FF for time2 0 time2 lt 0xFF time2 PORTD on On time of trigger signal j else for time3 0 time3 lt 0x0F time3 PORT Ds off Off time of trigger signal j DisplacementX_LEDs 0x0000 Reset X counter j j int main void sensor configuration SPI configuration Master Thesis 6 1 2 Step 2 flow chart no 6 Sensor Initialisation configuration Master Thesis 6 1 2 Step 3 with PLN2031 sensor product specification TwinEye init TwinEye cpi for Refer Master Thesis 6 1 2 step 2 to 4 flow chart no 7 Sensor_event read store and display Koninklijke Philips Electronics N V 2009 115 PR TN 2009 00597 Unclassified A 3 TwinEye Tlflashmodule c Master Thesis Track and Flash chapter 6 4 Trigger flash and control charging Implementation 4 This program makes use of confidential header files and functions include lt string h gt define AVRGCC include
38. band of the hair mela nin Table 1 Indications and expected efficacy for different hair removal devices 2 Laser or Light source Ll d Expected efficacy es 2 Normal mode ee mr ieee to light brown Long term hair removal Normal mode Alexandrite E Dark to light brown Long term hair removal ee ue e Pun Koninklijke Philips Electronics N V 2009 27 PR TN 2009 00597 Unclassified Table 2 Skin type and colour 2 en EN NM EDE dark intermediate dark Brown very dark Black Intense Pulsed Light sources are non coherent multi wavelength light sources By using appropriate filters the wavelength range from 600 1200nm can be emitted As mentioned in fig 5 Graph of absorption of melanin melanin has a wide range of absorption and in the range between 600 to 1200nm there is no major peak absorption of any other chromophore So using an intense pulsed light source deeply penetrating wavelengths which are most suitable for melanin of the hair can be obtained It can be used with single or multiple pulses with different durations and delay intervals The wide choice of wavelengths pulse durations and delay intervals makes IPL devices potentially effective for a wide range of skin types 2 28 Koninklijke Philips Electronics N V 2009 Unclassified PR TN 2009 00597 3 6 Limitations and Side Effects of Photoepilation Laser hair removal was FDA cleared in 1996 and has an excellent safety and efficacy profile
39. cal Cream applied to the skin dissolves the hair Epilation Epilation removes also part of the hair below the skin surface It can further be categorised as temporary or permanent 1 14 Koninklijke Philips Electronics N V 2009 Unclassified PR TN 2009 00597 Electrolysis is the method in which a fine needle is inserted into the skin A small current is applied to the hair follicle root which is burned out Each hair follicle must be treated individually and it may take several treatments to destroy the follicle It is a permanent hair removal method in most patients 4 Plucking is a temporary method a person stretches the skin and pulls out the hair using tweezers It is painful and time consuming because one can work on one hair at a time 4 Waxing is similar to plucking the only difference is that it removes many hairs at a time A wax is applied to the skin surface A cloth strip is then applied over the wax and quickly pulled off It is painful but less time consuming Epilator is a temporary hair removing method which removes the hair using a mechanical device Instead of pulling a single hair using tweezers as in the plucking method an electrically rotating roller is used which pulls out many hairs simultaneously but not as many as waxing does It is a painful method because multiple hairs are pulled out at a time from deep into the skin Photoepilation is the method of removing hair using a light source Light pen
40. des information about the speed of the moving object but not about its direction To find the direction the laser wave is modulated with a low frequency triangu lar wave which in turns changes the laser temperature fig 20 The change in the laser temperature in turn causes a change in laser frequency This change in laser frequency simulates small backward and forward movements of the object in the system on the rising and falling edges of the modulated laser power wave respectively 13 Due to this simulated motion there will be a Doppler shift observed even if the object is stationary But this Doppler shift will decrease if the source and sensor move in the same direction and vice versa when the movement is in the oppo site directions 13 A comparison of the Doppler shift on the rising and falling slopes of the resultant triangular modulated waveform yields the directional information of the motion 13 44 D Koninklijke Philips Electronics N V 2009 Unclassified PR TN 2009 00597 isa k la nbgakr dier dr er Wrede makalo ZN mELLL im en hn 3 h Ligh Lkw Argh Fw Figure 20 Twin Eye Laser Sensor technology 13 Photo Photo diode X diode Y Laser Laser E Laser safety Voltage Clock generator Barlin protection regulator power controller le g Y mE idm mm processor processor Heserved GND Decoupling XTAL N XTAL P MISO MOSI CLK CSn INTERRUPT Figure 21 Bloc
41. des results in terms of displacement of an object It can detect displacement of an object with high resolution and can detect the velocity of an object moving with a speed of upto 1m sec 14 42 Koninklijke Philips Electronics N V 2009 9 1 1 Unclassified PR TN 2009 00597 Twin Eye Laser Sensor Figure 18 Twin Eye Laser Sensor 13 The Twin Eye Laser Sensor works as follows A diode laser emitting light at 830nm is focused on the targeted object using an optical lens Light is scattered when striking the object except for an object that has perfect transparency or mirror reflection Part of this scattered light enters back into the sensor where it is optically mixed with light originating directly from the laser Constructive and destructive interference patterns are created If the object is moving toward or away from the light source the wavelength of the scattered light is shifted due to the Doppler effect The shift in the wavelength is proportional to the velocity of the object As a consequence of this the power of the mixed light fluctuates This fluctuation is detected by a photo detector The velocity of the moving object is derived therefrom 13 Koninklijke Philips Electronics N V 2009 43 PR TN 2009 00597 Unclassified Constructive Laser bearn reflected bearn i mixed beam Destructive Laser beam reflected bearn s mixed bear Figure 19 Constructive and destructive interference 13 This provi
42. e trates into the skin Light energy is absorbed by melanin present in the hair follicle which generates heat which damages the hair follicle It is not removing hair at the time of treatment but disturbing the hair cycle or destroying the hair follicle Lasers and IPL Intense Pulse Light are used as light sources 2 Re moving hair using photoepilation is temporary or permanent depending on its fluence rate If the fluence rate is less than 10 J cm then it removes the hair temporary but if the fluence rate is greater than 20 J cm then it damages the hair follicle strongly and results in long term hair removal 28 Koninklijke Philips Electronics N V 2009 15 PR TN 2009 00597 Unclassified Photoepilation Light has been used widely and effectively in medical science and cosmetics It is playing an important role for diagnosis and treatment Different parts of the spectrum interact in different ways with the body because they have different energies and that way different interactions with the human body are created Examples for the applications of light for medical purposes are the infrared light used for pulse oximetry thermograpy and near infrared spectroscopy Visible light is used for endoscopy ophthalmoscopy and photodynamic therapy Blue light is used for the treatment of jaundice X rays are used for radiotherapy Light is also used for a range of cosmetic treatments like for removal of un wanted hair skin rejuvenation wrin
43. e available a powerful flash module providing anticipated Track and Flash requirements e g flashes with 20J optical energy at a flash rate of 1 flash per second Basic safety features have been demonstrated in the existing system In a next step these would have to be integrated next to the exit window of the light source Furthermore a user interface system is needed which can provide a feedback to the user about the speed of treatment for example too fast or too slow next to displaying the status of the device like battery status system failure etc Koninklijke Philips Electronics N V 2009 105 PR TN 2009 00597 Unclassified References References 1 Ahluwalia S Editor 2009 Cosmetic applications of laser and light based systems William Andrew Norwich NY USA 2 Blume Peytavi U Tosti A Whiting D Tr eb R 2008 Hair growth and disorder Springer Berlin Germany 3 Dickinson B 2002 Photoepilation using a broad band intense pulsed light source Luminette and Lumina paper downloaded from the webpage http www forgoodhealth co uk depilite php Skin laser review group Department of Physics University of Manchester UK 4 Regan L 2007 Winning the battle against unwanted hair growth Divine Books Ramsey NJ USA 5 Are we at the Start of an At Home Device Revolution http www skinandaging com article 6270 7 Product TriaBeauty http www triabeauty com 8 Product Silk n http www sil
44. e the most common examples of gas discharge lamps Solid state light sources are light emitting diodes LEDs organic LEDs OLEDs and diodes lasers etc LEDs are basically semiconductor material diodes When the diode comes into forward bias electrons and holes are re combined and generate light The colour of the light depends on the energy gap of the semiconductor OLEDs are composed of organic material and emit light similar to LEDs In a laser radiation of light occurs through a stimulation proc 24 Koninklijke Philips Electronics N V 2009 Unclassified PR TN 2009 00597 ess The wavelength of the light generated by the laser depends on the active medium used such as gas solid state liquid and semiconductor diode lasers 1 For medical use lasers and IPL xenon flash lamp are used in many applica tions Lasers are devices that generate a beam of light that is collimated monochro matic and coherent The radiation of a laser can be characterized by its wave length power and the mode of light generation either continuous mode or pulse mode A continuous mode laser can work in pulse mode but most pulse mode lasers cannot work in continuous mode The lasing material used can be a gas liquid or a solid 1 From the gas lasers in which a gas is used as the lasing medium the carbon dioxide laser is mostly used in medical application for tissue ablation because of the high absorption by tissues It can generate wavel
45. ed DisplacementY LEDs deltaY stored volatile U8 Sensor report 6 define SPI INT 1 PORTD2 use only if SPI interrupt mode define SPI CGS 1 lt lt PORTB4 define SPI SCK 1 lt lt PORTB7 define SPI MISO O lt lt PORTB6 define SPI MOSI 1 PORTB5 define for Pulse Signal define on 1 lt lt PORTD5 define off 0 lt lt PORTD5 Master Controller Configuration void sensor_configuration Master SPI Configuration Master Thesis 6 1 2 Step 2 SPI DDR SPI CS SPI SCKISPI MISO SPL MOSI SPI PORT SPI CS IDDRD SPI INT SPCR 1 lt lt SPE 1 MSTHR 1 CPHA 1 SPR0 SPSR 1 lt lt SPI2X Master ouput Configuration DDRC OxFF Display LEDs DDRA OxFF Display LEDs DDRD OxDB Connect TI Flash to this port MITT Sensor IIT bit Sensor_event Sensor_report_reset reset refer Master Thesis 6 1 2 Step 4 TwinEye_report read the sensor if g_flwinEyeReport 1 TwinEye report read cycle finished g fTwinEyeReport 0 TwinEye_report can be read in next read cycle 114 Koninklijke Philips Electronics N V 2009 Unclassified PR TN 2009 00597 deltaX stored g ssTwinEyeDeltaX deltaX report stored deltaY stored g ssTwinEyeDeltaY deltaY report stored DisplacementX LEDs DisplacementX LEDs deltaX stored display on LEDs DisplacementY LEDs DisplacementY LEDs deltaY stored displ
46. ed hair is covered with flashes This procedure is called Step and Flash The SatinLux device has a fixed size of the light emitting window 8cmx1cm so at a time it can cover 3cm areas on the body Fig 9 shows the Step and Flash concept and how it targets the hair follicles ep 2 Sey Re Figure 9 Step and Flash As shown in fig 9 step 1 is to press the light emitting surface on the targeted skin area and trigger the flash Light penetrates into the skin Fig 10 shows a detailed view of the hair follicle before the flash and just after triggering the flash Koninklijke Philips Electronics N V 2009 33 PR TN 2009 00597 Unclassified 2 EM OO nn s Fr Figure 10 Hair in skin before flash and just after flash 21 The light selectively targets the melanin in the hair fig 11 The melanin absorbs the light and generates heat elevating the temperature of the hair follicle Figure 11 Melanin in hair heated hair bulb 21 As a consequence of this the hair goes into resting phase fig 12 A natural process sheds the hair Figure 12 Damaged hair area without hair 21 34 Koninklijke Philips Electronics N V 2009 4 2 2 Unclassified PR TN 2009 00597 Now back to fig 9 after step 1 the device is lifted up and moved to an adjacent area shown as step 2 There is some area in between where subsequent flashes overlap and there may be an area where there is no light penetrating into the skin O
47. engths in the infrared range from 9 2 to 11 1 um These lasers are tuneable within this range 1 From the liquid lasers in which a liquid is used as the lasing medium the dye laser is used in spectroscopy photochemistry of biological molecules and for blood vessels coagulation It can emit wavelengths from 340 960nm 217 380nm and 1060 3100nm 1 A solid state laser has as its active medium a matrix of crystal glass or ceramic doped by active ions As crystal matrices sapphire yttrium aluminium gar net YAG alexandrite and other materials are used in lasers Active ions can be Nd neodymium Cr chromium Er erbium Ho holmium Tm thulium and others 1 Active ions generate different wavelengths depending on the matri ces used The combination of Nd YAG is the one of the most efficient laser in photomedicine which generates light in the near infrared region e g 1064nm The Er YAG combination generates wavelengths in the mid infrared region i e Koninklijke Philips Electronics N V 2009 25 3 5 1 PR TN 2009 00597 Unclassified 2 9 2 94um It is used in tissue ablation 1 From the diode lasers one of the most used lasers is the GaAs laser using gallium arsenide GaAs as a semi conductor material It emits in the near infrared range NIR at about 830nm It can produce many wavelengths depending on the semiconductor material used 1 An Intense Pulsed Light source IPL is a xenon flash lamp that uses light emis si
48. ennneneneeeennnnnens 39 Figure 17 Laser self mixing technology 16 nanne nenen eene ennenvennnenrennneenvennnenvennnen 40 Figure 18 Twin Eye Laser Sensor 13 2 000 ccscccccccccsesseeeeccecsceseeseeeennscceseseeeceseccsccesseeeensasceesses 43 Figure 19 Constructive and destructive interference 13 nnen enneennnnenn eenen eens eennnns 44 Figure 20 Twin Eye Laser Sensor technology 13 aaa eeenennrenneneennnneenneervennnnens 45 Figure 21 Block diagram of Twin Eye Laser Sensor modules 13 l 45 Figure 22 Twin Eye Laser Sensor without lens 16 neenennnneeenneneennnnerrneeeeennnnens 47 Figure 23 Master and slave connection aan oansennnnrenseennnanenseennnanensvennnnenseennneens vennen 48 Figure 24 SPI shift registers ann eannnnnnennrennnnenreennnnnenreennnnnenseennnnensennnnnennseennnnenseneeennns 49 Figure 25 Microcontroller architecture and Interface devices 18 esses 55 Figure 26 the STK500 Evaluation Board 20 nanne eenennneernneeenennnnnrrnnereennnnnens 57 Figure 27 TeSt Dell Chi atacar nds tet dni qc ena aede bbb veo uem tei n cui eae READE 58 Figure 28 LabView program for mechanical Setup naannns enne eennanenneennnnenseennseens vennen 59 Figure 29 Implementation of Displacement Sensing u nuunnsenrennnnenneennnnnenseennnnsenseennns 60 Figure 31 STK500 Evaluallon Board ten eetbaar SU Rae toc aan uut onte dee 61 Figure 30 Block di
49. epends on the type of the targeted chromophore 1 Photomechanical Damage When light travels into the skin it is getting absorbed and generates heat This heat increases the temperature of the tissue and results in reversible or irre versible alterations in the tissue Multiple short pulses cause extremely rapid heating of the target A temperature greater than 100 C is causing photome chanical destruction of tissue Due to the high temperature pressure is gener ated in the tissue which can stimulate shock wave formation and mechanical damage of the tissue 1 Photomechanical destruction of hair has been at tempted with very short nanosecond pulses by Q switched 1064 nm Nd YAG lasers both with or without carbon suspension as an additional chromophore 2 Hair follicles targeted with very short pulses cause extremely rapid heating of the chromophore This generates photo acoustic shock wave which leads to photomechanical destruction Photothermal Damage Photothermal damage is related to the method of use of light as used in photo mechanical damage the major difference is that instead of shockwave genera tion this works by thermal transfer In photothermal damage the tissue tem perature does not rise above 100 C 1 Photothermal damage is based on the principal of selective photothermolysis 2 We consider devices using the photothermal damage method Koninklijke Philips Electronics N V 2009 17 3 3 1 PR TN 2009 0059
50. equency This is set to one 21 Koninklijke Philips Electronics N V 2009 T1 PR TN 2009 00597 Unclassified NOTE In actual program this settings are done in the main routine namely sensor configuration Step 3 Sensor Initialisation A program written for USB gaming mouse application and a confidential product specification was received from Philips Lighting Laser Sensors After power on or in case of an error the program initializes the sensor This information is confidential and not described in this report Step 4 Displacement reporting The displacement reporting is reading the sensor registers The microcontroller reads sensor registers at every 2ms These registers contains information of displacement Flow chart no 7 shows detailed information of the displacement report event NOTE In program it is in main in IwinEye init namely IwinEye report 78 Koninklijke Philips Electronics N V 2009 Unclassified PR TN 2009 00597 Select Sensor CSn low Read Status register delta X register and deltaY register of the sensor Is Valid bit high and Motion bit high Read and Store Store x register data sensor displacement Store Y register data Decelect Sensor CSn high X directional displacement LEDs previous data new data Wait Ams Flow Chart 7 Displacement report and store Select Sensor CSn low To start SPI communication the microcontrolle
51. er Sensor 6 2 1 Hardware The mechanical setup described in chapter 5 3 is used in this implementation Faulhaber MINIMOTOR b RS 232 ff STK 500 Evaluation board Figure 53 Block diagram of experimental setup The Twin Eye Laser Sensor has been mounted on the mechanical setup de picted in fig 54 The sensor is placed at a radius of 65mm from the centre of the disk 88 Koninklijke Philips Electronics N V 2009 Unclassified Twin Eye Laser Sensor STK500 Evaluation board a 0 Q Q u a 2 PR TN 2009 00597 1 Figure 54 Experimental setup Koninklijke Philips Electronics N V 2009 89 PR TN 2009 00597 Unclassified 6 2 2 Software TwinEye c The motor in the mechanical setup and the LabView program used for control ling the motor parameters refer chapter 5 3 was developed by the E amp I de partment of Philips Research Aachen The program for the Twin Eye Laser sensor is remaining the same as described in the chapter 6 1 6 2 3 Results The sensor is operated at different speeds and the resulting total counts are determined every 10 seconds upto 60 seconds Results obtained are shown in the following graph As expected the graphs are linear and their slope is propor tional to speed 1400 1200 counts at velocity 10mm sec 1000 COUNTS at velocity SOmm sec 800 IU e counts at 600 velocity 100mmj sec Fas 0 COUNTS at i l p rt velocity 128mmj
52. es that offer many of the advantages of professional treatment and 30 Koninklijke Philips Electronics N V 2009 Unclassified PR TN 2009 00597 put them right within customers hands at their own home Home hair removing devices are expected to become increasingly popular in the near future The key benefits are privacy convenience affordability and no committed appoint ments at a clinic TriaBeauty 7 Silk n 8 Philips SatinLux 9 are some exam ples of the devices that are in the market Hence innovative devices provide individuals with the ability to remove un wanted hair safely and effectively in the comtort of their own home while this method can save users plenty of time and money Philips SatinLux fig 7 is one of the at home hair removing devices The proce dure is non invasive requiring no needles or chemical applications Compared to electrolysis large areas of skin can be treated in a shorter period of time This device removes hair using the IPL technology The IPL technology is discussed in chapter 3 5 Light Sources Figure 7 Philios SatinLux photoepilation device 22 Fig shows the key parts of the SatinLux device No 1 is the device on off switch No 2 is the light exit window with a filter glass in it No 3 is the safety Koninklijke Philips Electronics N V 2009 31 PR TN 2009 00597 Unclassified system comprising several contact switches Only when all of these switches are fully pr
53. essed then a flash can be released No 4 is the safety indication a light indicates when the safety switches are pressed and the device is ready to flash No 5 is the button for adjusting the flash intensity from level 1 to 5 The required intensity level depends on the skin and the hair type No 6 is the flash trigger button Use of this device is easy The user has to adjust the intensity level of the light according to the skin and the hair type as described in the manual The operation of this device uses a concept called Step and Flash rmm User Interface User Feedback Control Safety System Figure 8 Block diagram of SatinLux device Fig 8 shows a block diagram of the SatinLux device The flash is operated by the user through the control unit User inputs represent the trigger button and the flash intensity adjust button User feedback is representing the status of the safety system and the intensity level All modules are connected to internal control unit 32 Koninklijke Philips Electronics N V 2009 4 2 4 2 1 Unclassified PR TN 2009 00597 Step and Flash Concept The device s light emitting surface is pressed on the skin and then a flash is triggered Then the device is moved to an adjacent part of the skin area The light emitting surface is pressed on the skin again and then a flash is triggered again This procedure is repeated step by step until the entire body part with unwant
54. from the Step and Flash concept to the Track and Flash concept a new and important module added is Displacement Sensing This also affects other modules the flash mechanism feedback system and safety system In the flash mechanism as the device moves continuously across the skin flashes have to be released automatically As to this it is a related challenge to in crease the frequency of flashes The safety and feedback system have to be adapted to the higher flash rate The safety system has to be adapted to the automatic flashing and continuous movement of the device An algorithm has to be implemented in the feedback system to control the automatic flashing To implement the Track and Flash concept the major new components not used in Step and Flash are a displacement sensor and a microcontroller Displacement Sensor Optical displacement sensors are used in computer mice When one moves the mouse on a surface it gives a fast response on the monitor These sensors are flat there are no mechanical moving parts and they work on opaque partly reflecting surfaces Avago and Philips manufacture optical displacement sensors As to their work ing principle Avago sensors are based on image processing see chapter 4 3 2 and Philips sensors are based on self mixing interference see chapter 4 3 2 A Philips sensor was used because internal technical help and sample pieces could easily be obtained The Philips Twin Eye Laser Sensor provi
55. ht sources are candles incandescent light bulbs etc Candles consist of fuel mate rial mostly wax or fat When it comes into contact with fire using oxygen a reaction starts and gives output in form of visible light and carbon vapour In an incandescent light bulb the electricity goes through the connecting wires into the bulb The electricity then gets forced to go through a very tiny and thin wire called the filament The electrons have a tiny amount of space to go through so the filament heats up The filament then gets heated up until it finally glows Incandescent light bulbs are not very efficient because a large portion of the electricity is converted to heat instead of useful light It also takes a long time to get heated up A gas discharge tube uses a low pressure gas or high pressure gas to create light Gases used are mercury neon argon xenon and krypton A gas dis charge tube with low pressure has no electrode inside Light is generated by an electrical discharge the gas gets ionized and forms a plasma A high pressure filled gas discharge tube called arc lamp has electrodes inside The gas be tween two electrodes between which a high potential difference exists gets ionized and forms a plasma The free electrons in this plasma allow current to flow between the electrodes The plasma either generates light directly or by causing another material to create light The mercury lamp and Intense Pulsed Light xenon flash lamp ar
56. igger signal can be controlled externally The capacitor storage capacity is 5 3 J The energy emitted by the flash should be in the order of 10 of the energy stored in the capacitor 98 Koninklijke Philips Electronics N V 2009 Unclassified Figure 65 Texas Instruments evaluation module Twin Eye 3 3 V 0 100Am P Laser Sensor 12V 0 500Amp Microcontroller Complete 3V LAm p Tl evaluation SV 0 300Amp module Figure 66 Blcok diagram of setup 2 PR TN 2009 00597 The above block diagram shows the connection of the TI Evaluation Module to the microcontroller and the Twin Eye Laser Sensor Koninklijke Philips Electronics N V 2009 PR TN 2009 00597 Unclassified flash lamp Twin Eye Laser Sensor Figure 67 Experimental setup The TI Evaluation Module is mounted on the experimental setup as shown in figure 67 3V 1Amp 5V 0 300Amp CHARGE COMP Charging Capacitor LED Indication of Device is not ready SS PB2 MISO PB4 PB6 GND Figure 68 connection between sensor microcontroller power supply and TI Evaluation Module 100 Koninklijke Philips Electronics N V 2009 Unclassified PR TN 2009 00597 As shown in the above connection diagram the capacitor charging and flash triggering signal is provided by the Port D of the microcontroller The negative edge from the pin D1 will start charging of the capacitor of the flash The micro
57. in illuminated state for the sensor to work In the sate state the system begins by checking whether a defined value of counts is reached to indicate Motion After acknowledging Motion the capacitor charging is started by sending an active low signal to the capacitor charging pin pin D1 The micro controller gets acknowledgement that the capacitor has been charged by read ing the status of the pin D2 while reading sensor displacement register at the same time When the counts reach a preset value which determines the definite distance travelled by the sensor the microcontroller checks the capacitor charge condition and safety condition before triggering the flash The system uses System Check LED to indicate whether the user is moving too fast or not The System Check LED pin D7 will glow only if the system is not ready The flash is triggered only if the sensor has travelled a defined distance But if the sensor reaches this count before the capacitor has been charged the LED con nected to pin D7 will glow and indicate that sensor is moving faster than the charging rate of the capacitor The Track and Flash mode is designed for treating larger areas on the body If the user wants to use the device in a smaller area of the body the Step and Flash concept can be used by neglecting the data from the displacement sensor and just waiting for the capacitor to be fully charged and a flash can be gener ated by pressing the Step and Flash mode switch
58. k diagram of Twin Eye Laser Sensor modules 13 Koninklijke Philips Electronics N V 2009 45 PR TN 2009 00597 Unclassified The Philips Twin Eye Laser Sensor uses two lasers that are placed in orthogo nal directions This way it can provide both x and y coordinate information Each laser has its own individual photo detector which detects power fluctua tions in the mixed light fig 21 This is further processed in an Application opecific Integrated Circuit ASIC which uses signal processing and filters to determine the Doppler shift This ASIC controls the laser power to maintain in Class 1M eye safety limits 13 The Twin Eye Laser Sensor has 11 pins fig 21 4 for SPI communication MOSI MISO CLK CSn 2 is for external clock supply 1 is for ground 1 is for 3 3V power supply 1 is for interrupt control 1 is for decoupling and 1 is re served 13 Connections and functions of these pins are described in the next chapter in section implementation 1 The Twin Eye Laser Sensor has three major advantages 1 the laser source is optically connected with the photo detector as a single module So the optical paths from the source to the surface and vice versa are identical This elimi nates alignment problems of reference length with respect to object length Because of the single path there is no need of extra optics for focusing scat tered light on the photo detector 2 It reduces system cost 3 It can even work with highl
59. kles cellulite reduction and acne treatment The concept of hair removal using light is based upon the principle of selective photothermolysis 2 It damages hair follicles in such a way that it slows down or stops re growth It has shown effective and long term results This damage can happen because of the absorption of light in melanin Melanin is a natural chromophore in the hair follicle which absorbs light and radiates heat into the surrounding area Other chromophores in the skin i e hemaglobine oxy haemaglobin and water also absorb light Hair removal using light sources is getting increasingly popular Lasers with different wavelengths and IPL Intense Pulse Light are used for hair removal 2 It is effective but knowledge about appropriate treatment is necessary since otherwise it can cause side effects There are three mechanisms by which light can damage hair follicles 2 Photochemical damage Photomechanical damage Photothermal damage 16 Koninklijke Philips Electronics N V 2009 3 1 3 2 3 3 Unclassified PR TN 2009 00597 Photochemical Damage Photochemical interaction of light with tissue is of great interest for cosmetic treatments like skin aging process tissue repairing rejuvenation hair removal treatment Photochemical damage is the use of light to produce a targeted photochemical reaction and therapeutic effect This chemical reaction damages cell membranes and the protein This reaction and effect d
60. kn com 9 Product SatinLux http www consumer philips com c photo epilator satinlux 32844 cat gb 10 paper downloaded from the Avago s webpage http www avagotech com pages resources white papers ZNID Optical Mice and How They Work The Optical Mouse is a complete imaging system in a tiny package 11 paper downloaded from the Avago s webpage http www avagotech com pages resources white papers ZNID Understanding Optical Mice 12 Paper downloaded from the PHILIPS webpage http ww6 business sites philips com lasersensors technology index html Principles of the laser self mixing technology 13 White paper downloaded from the PHILIPS webpage http ww6 business sites philips com lasersensors technology whitepapers Index html Technology White Paper Philips Laser Sensors twin eye laser technology and applications 14 Reference page and downloaded from the PHILIPS webpage http ww6 business sites philips com lasersensors technology Index html Technology 15 PHILIPS Confidential product information Twin Eye Laser Sensor product specification 16 Images downloaded from the PHILIPS webpage hitp ww6 business sites philips com lasersensors news downloads Index html 17 Steven F Barrett and Daniel J Pack 2009 Atmel AVR Microcontroller Primer Program ming and Interfacing Morgan amp Claypool San Rafael CA USA 106 Koninklijke Philips Electronics N V 2009 Unclassified PR TN
61. le The flash lamp module connector has 9 pins The descriptions of these pins are shown in the following table Table 8 Hamamatsu flash lamp module Pin functionality Vin 11V to 28V Supply voltage Vin 11V to sVin fiVto28V Supply voltage voltage Ki iliac 3 2V to4 8V n supply voltage for discharge Not used in this project TRIG 5V Positive EN LL MEN signal Vin RTN Heturn of Pin1 Vin RTN Heturn of Pin 2 Vref RTN Heturn of Pin 3 92 Koninklijke Philips Electronics N V 2009 EN TRIGRIN RTN Return of Retumoff gge an an 9 o Unclassified PR TN 2009 00597 Pin 3 can be used for the external adjustment of the main discharge voltage If the switch shown in fig 59 is at EXT then this pin is connected But an internal discharge circuit is used for this project see fig 60 set INT Figure 59 Internal charging This flash lamp is triggered by a pulse width modulation signal from the micro controller generated by software Twin eye 3 3 V 0 100Amp Laser Sensor 12V 0 500Amp Microcontroller PWM signal from Port D to Pin5 Xenon Flash Lamp Figure 60 Block diagram of implementation 2 Koninklijke Philips Electronics N V 2009 93 PR TN 2009 00597 Unclassified 94 amamatsu flash lamp Twin Eye Laser Sensor Figure 61 Mechanical setup with Hamamatsu flash lamp module 1 on g su EE ME J a D e DJ LA Figure 62 Connection between sen
62. lt avr io h gt include C sensorprogram6 config h include C sensorprogram6 mouse_wired_philips_drv h include C sensorprogram6 TwinEye_api h define Sensor report reset Sensor report 0 0 Sensor report 1 0 Sensor report 2 0 Sensor report 3 0 Sensor report 4 0 Sensor report 5 0 unsigned int DisplacementX LEDs deltaX stored DisplacementY LEDs deltaY stored volatile U8 Sensor report 6 define SPI INT 1 PORTD2 use only if SPI interrupt mode HT MIIIIIIIIDetine SPI AMM define SPI CS 1 lt lt PORTB4 cheap Select define SPI SCK 1 lt lt PORTB7 CLOCK define SPI MISO 0 lt lt PORTB6 MISO define SPI MOSI 1 PORTB5 MPOSI lIIII I Master Controller Configuration void sensor configuration Master SPI Configuration Master Thesis 6 1 2 Step 2 SPI DDR SPI CS SPI SCKJ SPI MISO SPI MOSI SPI PORT SPI CS DDRD SPI INT SPCR 1 lt lt SPE 1 MSTR 1 lt lt CPHA 1 SPR0 SPSR 1 lt lt SPI2X Master ouput Configuration DDRC OxFF Display LEDs DDRA OxFF Display LEDs DDRD OxDB Connect TI Flash to this port For Texas Instruments Flash Microcontroller PORT Settings DDRD BV 1 PORTD BV 1 Use For Charging Capacitor DDRD amp _BV 2 116 Koninklijke Philips Electronics N V 2009 Unclassified PR TN 2009 00597 PORTD BV 2 Use Indication from TI capacitor is fully cha
63. n option This configures master device ready for communication After comple tion of each cycle the SPI Interrupt Flag SPIF is set in the SPSR register Reading the SPSR and SPDR registers clears this flag 17 19 50 Koninklijke Philips Electronics N V 2009 Unclassified PR TN 2009 00597 Slave Initialization Configure MISO as output pin Set bit SPE of the SPCR register Clear SPI Inter rupt Flag by reading SPSR and SPDR Flow Chart 2 Slave device configuration flow chart The slave receives input from the master of the clock data and slave se lect deselect pin So these pins should be set as input Only the MISO pin is set as output so it can shift data to the master device The second step is to set SPI enable mode The third step is same as for the master device i e the SPIF is cleared by reading the SPSR and SPDR registers 19 After each cycle the master must deselect the slave device via disabling SS pin SS low so that the slave device can get ready with new data for transmission This cycle is repeated Between two cycles the microcontroller does other tasks 19 Koninklijke Philips Electronics N V 2009 51 PR TN 2009 00597 Unclassified SPI Communication Controlled by Interrupts The master device reads data from slave device when interrupt occurs 19 Flow chart 3 shows the master device SPI configuration in interrupt mode In interrupt controlled SPI communication there is
64. n sensor microcontroller and power supply 70 Koninklijke Philips Electronics N V 2009 6 1 2 Unclassified PR TN 2009 00597 Software TwinEye c Step 1 STK500 user interface settings through AVR Studio Version 4 16 The STK500 board with the ATmega8515L microcontroller mounted on it is connected to the computer through the RS 232 Port described in chapter 5 1 1 hardware In AVR Studio one has to set device selection and related settings as shown in the flow chart below This setting window fig 40 can be accessed using the following menu 20 Tools Program AVR connect platform STK500 Port Auto connect Note This window fig 40 can be accessed if the microcontroller is connected to the PC otherwise it will be grey Fuses Settings Program Configuration HW Settings TL EN ond Tove NL IF AlmegaBS1S AVR Simulator Auto o Figure 40 AVH Studio interface for setting STK500 configuration Koninklijke Philips Electronics N V 2009 71 PR TN 2009 00597 Unclassified Flow Chart 5 STK500 user interface settings using AVR Studio Start AVR Studio Configuration Main Configuraton Program Configuraton Fuses Settings HW Settings End AVR Studio Configuration Flow Chart 5 AVR configuration 72 Koninklijke Philips Electronics N V 2009 Unclassified PR TN 2009 00597 Main configuration refer fig 40 in the device section the ATmega8515 is se lected The microcontroller can be pr
65. ne 60 6 1 2 SOWArS AT WINEVEGN urne 71 De LIU mI 85 6 2 Displacement Sensing in the Mechanical Setup Implementation 2 88 D ALO WANG nea e diuo tat uad deti eeducte caste udo dedLE 88 6 2 2 Software TwinEye C renie a a 90 629 LI ncc EDEN 90 6 3 Displacement Triggering Flashes Implementation 3 ssssusess 91 SPON MEN LI Lucre ER 91 6 3 2 Software TwinEye Hamamastuflashmodule c 95 Goe MeSUS um ias a trails Gut M acad balkenende ken ed 97 6 4 Trigger Flash and Control Charging Implementation 4 98 DT AWS redeneren dutustontia a 98 6 4 2 Software TwinEye_Tlflashmodule C nnn eeneneeeeneeeeennnen 102 s DE 104 Conclusions and Outlook iiio ci Mes cut coco acre ioc i ie eee 105 HEIerenCeS we 106 eil 108 BE n ge Ir E PPS MES 110 LOW ILI Leer E 111 A CO tassi ded ce eea h annot cud ded dan mu OIM ELA ute 112 AT TWIN YO ee 112 A 2 TwinEye Hamamatsuflashmodule C naunns enne eennnrenreennnnenr ennen eenn 114 A 3 TwinEye Tlflashmodule c nuunneanseennnsenneennserrseennnsernsennnnnennvennnnsenseenn 116 Koninklijke Philips Electronics N V 2009 7 PR TN 2009 00597 Unclassified Introduction Every individual irrespective of gender and social status strives to have perfect looks and beautiful skin Removal of unwanted hair has been
66. nnnsenseeennneenseeennnnens vennen 82 Figure 47 valid Bit highi data are vald snenie voro so ake epulo eo oret de eor teo cio ee Feo Pese ver oes 84 Figure 48 Sensor tested on laminate surface seeeeessssssssessseesseeeeennn nennen nnns 85 Figure 49 Sensor tested on smooth glossy white surface nnuunnnnsnennne een ennnnenneeeennnnnenn 86 Figure 50 Sensor tested on translucent SUPACE ccccceccceeeeesseeeeeeeeseeeesseeeeeeseneasseeeeeeessnneaaaees 86 Figure 51 Sensor tested on the mirror eeren nennen nennen nennen 87 Figure 52 Sensor tested on the Skim seii eoe esee i ed ou keien eenden US aad 87 108 Koninklijke Philips Electronics N V 2009 Unclassified PR TN 2009 00597 Figure 53 Block diagram of experimental Setup aan sarennnren ennen vennnrerennnnen vennen vennen 88 Foure St Experimehtal SSID enteren aad temeer eden ana OM BILD cada Com wu hee kn 89 Figure 55 Sensor counts at different velocity nnn neeeenennennnnnnnnsseerennnnnneeevenennnnnnnnens 90 Figure 56 Implementation of Track and Flash with Hamamatsu flash lamp module 91 Figure 58 Pin diagram of the Hamamatsu xenon flash lamp module 92 Figure 57 Hamamatsu xenon flash lamp modul naan enn ennnseneennenrennsenrennnsene ennen 92 Figure 60 Block diagram of implementation 2 un unnsnns enn ennnens eneen vennnenvennnensennnsenesensen 93 Figure SS
67. not priority to set first SS MOSI and SCK bits as output before SPE bit as it is mandatory in polling mode SPI communication The third step is different compared to polling mode Here the master has to configure speed of SPI communication and enable SPI interrupt opeed of SPI communication is set by dividing the system clock with a factor of 64 or 128 This is because interrupt consumes many cycles for storing ad dress recall flag generation etc In interrupt routine it consumes nearly half of system clock SPI division helps to make it faster Interrupt can be set by ena bling SPI Interrupt Flag SPIF in SPCR register After transmitting receiving data clear the interrupt flag by reading the SPSR and SPCR registers If Global Interrupt is set then this will perform the tasks defined to perform on the SPIF interrupt flag set 19 52 Koninklijke Philips Electronics N V 2009 Unclassified PR TN 2009 00597 Master Initialization Configure SS ONS IE Talo ESON as output pins Set bit SPE and MSTR of the SPCR register Select SPI speed and enable SPI Interrupt Clear SPI Inter rupt Flag by reading SPSR and SPDR Enable global Interrupts Return Flow Chart 3 Interrupt controlled Master device flow chart Koninklijke Philips Electronics N V 2009 53 PR TN 2009 00597 Unclassified The slave device configuration is similar to the master device configuration it differs only in the first step the MISO
68. ntroller Acknowledged capacitor is fully charged PORTD BV 1 Capacitor stops Charging PORTD BV 4 Trigger OFF j Refer Master Thesis 6 1 2 step 2 to 4 flow chart no 7 Sensor event read store and display Refer Master Thesis 6 4 2 flow chart no 9 if bit is clear PIND 3 Step and Flash mode switch unsigned int time1 time2 while bit is clear PIND 2 Microcontroller Acknowledged capacitor charged PORTD amp BV 1 Capacitor starts charging PORTD amp BV 7 LED On indication Device is not ready f l bit is clear PIND 5 Safety Switch PORTD _BV 6 Main Safety Off else PORTD amp _BV 6 Main Safety is on j 118 Koninklijke Philips Electronics N V 2009 Unclassified PR TN 2009 00597 PORTD BV 1 Capacitor stops Charging PORTD BV 7 LED Off Indication Device is ready to use Capacitor is Charged while t bit is clear PIND 5 Safety check PORTD BV 6 Safety Off Dust 0 time1 lt 0x017F time1 PORTD amp BV 4 Trigger ON T PORTD BV 4 Trigger OFF j j j else PORTD BV 6 Main Safety Off if bit is clear PIND 2 Microcontroller Acknowledged capacitor is fully charged PORTD BV 1 Capacitor stops Charging PORTD amp _BV 7 LED On indication Device is not ready j PORTD BV 7 LED Off Indication Device is ready to use Capacitor is Charged Koninklijke Philips
69. ogrammed using In System Programming and High Level Programming In System Programming ISP is selected The Program configuration is used to load the HEX code of the program to the flash memory of the microcontroller STK500 in ISP mode with ATmega sis n x Main Program Fuses LockBits Advanced Hw Settings Hw Info Auto Device Erase Device W Erase device before Hash programming v Verify device after programming Flash Use Current SimulatarzEmulatar FLASH Memory Input HEX File C sensorprogram defaultsensorprogramB hex Program Verity Head EEPROM Figure 41 Program configuration in AVR Studio Fuses settings The SPI Enable fuse SPIEN is selected automatically when selecting the ISP mode STK500 in ISP mode with ATmegadsis i nml x hi ain Program Fuses LockBits Advanced Hw Settings Hwy Infa Auto Fuze Value 58515C WOTOM SPIEM me EESAWE C BOOTS Boot Flash size 1024 words Boot address 0C00 bad BOOTRST CKOPT BODLEWEL Brown out detection at VL Z 7 M BODEN mm SUT CESEL Ext Chock Start up time 6 CE 64 ms w HIGH 009 LO OE 0 vw Auto read Figure 42 Fuses settings in AVR Studio Koninklijke Philips Electronics N V 2009 73 PR TN 2009 00597 Unclassified HW settings In SPI communication the microcontroller is the master device and the Twin Eye Laser Sensor is the slave device As described in its d
70. on of a plasma bridge formed in a gap between two conductors 1 Intense Pulse Light Sources IPL is used in spectroscopy and dermatology They are filled with xenon and krypton gas known as xenon lamp or krypton lamp respec tively They are emitting the entire wavelength of visible light including UV and IR present in the electromagnetic spectrum Light Sources for Hair Removal For hair removal we need a light source which has a controlled flash operates in pulse mode and should not generate much heat while producing light Con trolled flash means that it can be flashed within millisecond just after triggering In pulse mode the duration of a pulse can be controlled and as described pre viously selective photothermolysis principle the pulse duration plays an impor tant role for the hair removing concept The generation of extensive heat with light will create a burning effect on the outer layer of the skin which has to be avoided for the removal of hair An incandescent lamp generates a significant amount of heat while generating light It needs start up time and shut down time It first gets heated up and then radiates light So it is hard to control the radiation of light It cannot be operated in pulse mode which is very important for hair removal application Because of this incandescent light sources are not used for hair removing application Gas discharge lamps have the advantage that they can radiate all wavelengths of visible
71. ontrolled PWM signal from the Port D Pin 1 of the microcontrol ler has been given as input to the xenon flash lamp to trigger the flash The turn on pulse is given for 0 6ms 96 Koninklijke Philips Electronics N V 2009 6 3 3 Unclassified PR TN 2009 00597 Reset counter The counter is reset by the microcontroller just after triggering a flash Results The flash has been generated at every 0x007F counts travelled by the sensor The trigger rate is fast enough but the intensity of the flash was not enough to heat up the disk and so the hot spots could not be observed by the thermal camera on the rotating disc Koninklijke Philips Electronics N V 2009 97 PR TN 2009 00597 Unclassified 6 4 Trigger Flash and Control Charging Implementation 4 The Hamamatsu flash lamp module is replaced by a higher intensity lamp The aim of the experiment is to heat up the disc to higher temperature in order to check whether flashes are overlapping Basic safety features are also imple mented USTANT ol e LOL d 34 15 28 gt USTA ere Co E p En ae Displacement Sensing peel Le Figure 64 Implementation of Track and Flash using TI Evaluation Module 6 4 1 Hardware The Texas Instruments TPs6555xEVM 097 Evaluation Module Tl Evaluation Module can emit larger amounts of energy than the Hamamatsu flash module A flyback converter charges the photo flash capacitor up to 300V Capacitor charging and tr
72. or will erase Status register deltaX register and del taY register X directional displacements LEDs The sensor is tracking in the X direction which is stored in the memory register of the microcontroller These stored data is displayed on the 16 LEDs of the STK500 board On every increment of the register the LEDs are updated on the board As the sensor measures dis placement this count is incremented and the result is interpreted based on the LED pattern on the board Polling mode 2ms The sensor is read at intervals of 2 0ms The reason for reading the sensor at intervals of 2 0ms is to give it time to update new data into the deltaX and del taY registers A delay count has been implemented so that the sensor data is read every 2 0ms As shown in the oscilloscope printout fig 47 every 2 0ms the valid bit is getting high for 0 2ms and data are read from the sensor Koninklijke Philips Electronics N V 2009 83 PR TN 2009 00597 Unclassified Dct fns HRHR CDPA I6 31 3 rs aM or minibar rri RED MLS e 5H ys LO mm See I EN LOD pal Fi py _ ee bt a Koe Se T Centronics P Vand p e Jan as 4 auto print x fu no uv re eene LIF F am gesn Jeti jdi E 4 Deka en division 4 H NM at pk 2 44m Laa 200 l eant Fil 4m Sdeut2 5O 5m nmsc2 L 5n 5 ampl 2 h51 E d pi 2 M L0 WSs 3 IC SET 2 DC 13
73. pin directions In this setup the microcontroller is the mas ter device and generating the SPI bus signals SCK MOSI and the CSn for communication with the slave device and receiving data from the slave device on the MISO pin 21 Koninklijke Philips Electronics N V 2009 75 PR TN 2009 00597 Unclassified Table 5 Master and Slave pin configuration 21 15 MOSI Output Input default configuration MISO Input Output default configuration SCK Output Input default configuration CSn Output Input default configuration SPCR register configuration SPCR is the SPI control register It has 8 differ ent bits that affect the performance of the SPI communication These 8 bits and their configuration for this project are as follows 21 Table 6 SPI Control Register SPCR 21 SPIE is set to zero low it stands for SPI Interrupt Enable When this is set as high SPI communication will trigger an interrupt In this project polling mode communication described in the previous chapter is used so this flag is set as low 21 SPE SPI Enable is set to one high to enable for SPI communication 21 DORD controls the structure of the data bytes Either the LSB of the data word is transmitted first or the MSB This bit is set to zero so the MSB will be trans mitted first 21 MSTR is set to one This selects the microcontroller as master device Setting MSTR to zero will select the microcontroller as the slave device 21
74. r growth for a longer time without any shaving cream or chemical The principle behind the temporary hair removal is exactly the same as in SatinLux The difference is that this device will be more sophisticated less time consuming to use How to Implement the Track and Flash Concept The Track and Flash concept implies a device comprising a tracking module and a flash module Both communicate with each other in order to perform flashes at predefined intervals guide the treatment speed in a way to give opti mum results of treatment and make the treatment fast and safe for at home USE 36 Koninklijke Philips Electronics N V 2009 Unclassified PR TN 2009 00597 Figure 13 Track and Flash concept Fig 13 shows the Track and Flash concept Compared to Step and Flash shown in fig 9 where flashes are released in a sequence of steps here the device is tracked across the skin Flashes are released in a continuous manner within predefined intervals of distance and overlap at the border area User Input 5 User Interface 5 User Feedback Control Displacement Sensing Figure 14 Track and Flash device concept Safety System Koninklijke Philips Electronics N V 2009 37 PR TN 2009 00597 Unclassified Fig 14 represents the block diagram of a device that would implement the Track and Flash concept Compared to the SatinLux device block diagram shown in fig 8 one module is added that
75. r is fully charged PORTD amp BV 1 Capacitor starts charging PORTD amp BV 7 LED On Indication Device is not ready If t bit is clear PIND 5 Safety Switch PORTD BV 6 LED On Indication Safety is On j else PORTD amp BV 6 LED Off Indication Safety is Off Safety switch is not pressed j PORTD BV 1 Capacitor stops Charging PORTD BV 7 LED Off Indication Device is ready to use Capacitor is Charged while bit is clear PIND 5 Safety Check Koninklijke Philips Electronics N V 2009 117 PR TN 2009 00597 Unclassified wait until main safety button pressed and 0 time1 lt 0x017F time1 Trigger On time PORTD amp BV 4 Trigger Pulse for time2 0 time2 lt 0x000F time2 This is only delay before capacitor starts charging again Past dud Trigger OFF Reset Counter j j j int main void sensor configuration SPI configuration Master Thesis 6 1 2 Step 2 flow chart no 6 Sensor Initialisation configuration Master Thesis 6 1 2 Step 3 with PLN2031 sensor product specification TwinEye init TwinEye cpi for Refer Master Thesis 6 4 2 flow chart no 9 if bit is clear PIND 5 Safety Switch PORTD amp _BV 6 Main Safety is on if DisplacementX_LEDs 0x0005 Use If movement occurs on sensor PORTD amp _BV 1 Capacitor starts charging j if bit is clear PIND 2 Microco
76. r sets the SS pin to the active low state this will select the slave and start the SPI clock as shown in the fig 44 Koninklijke Philips Electronics N V 2009 79 PR TN 2009 00597 Unclassified led HARD Int Printer Fi py dih Ki BPTI Rs Centronics E idi On Stave Sei ct gt Or dense Figure 44 Slave select SPI clock Read Status register deltaX register and deltaY register of the sensor The Status register deltaX register and deltaY register are 16bit registers in the Twin Eye Laser Sensor The deltaX and deltaY registers hold data for X and Y displacement respectively In one read cycle 7bytes are being transferred and received in serial mode In the first byte the microcontroller transmits an address to the slave So in the microcontroller data received by the first byte is neglected The remaining 6 bytes received by the microcontroller are Status register deltaX register and 80 Koninklijke Philips Electronics N V 2009 Unclassified PR TN 2009 00597 deltaY register respectively The figure 45 shows the transter of 7 bytes in a typical read cycle It shows clock cycle in slave select condition Fig 46 shows data transfer on the MISO line on slave selection Th Gach Stave Select E cic caa for 2 bye UNS iml i HHRUCUPY i 7 TIr n output tg t 1 MH MI pe Hii n Nu I it in T wr 5232 BI
77. re 1 Anatomy O Nar cle eel 10 Figure 2 Pigmented eellsin Skin 26 seamen ietose eoe va eer Uva eot oae ERE ao ee toe soo Yee anette meee 11 ae Bee Ine EN 27 e TE NE E NEN 12 Figure 4 Aal growth cyele 25 serene vereen olma Te VEU sv EY ok Da voe Paru cu dee 13 Figure 5 Relative absorption of melanin blood and water 24 ann oanennn enn enenenenennen 18 Figure 6 MISIDIe light Spectrum 23 Gerbennn enten ver nere Qa ver va voe Era dr eden 23 Figure 7 Philips SatinLux photoepilation device 22 nnen eennnnnenn nennen enne ennnneens vennen 31 Figure 8 Block diagram of SatinLux G VICE 20 cccccceccseeeseeedeceecccsseeeececeescceesseeeececeseccceeseseeeteees 32 Figure 9 Step andsEIasbiusseseas inae temi tates eeen eaten beheerste sik 33 Figure 10 Hair in skin before flash and just after flash 21 annen ennen ennen 34 Figure 11 Melanin in hair heated hair bulb 21 oan annennnnnenneeennnrenseennnneens vennen 34 Figure 12 Damaged hair area without hair 21 nonnen eeennnnenseennnnnenseennnnsens ennen 34 Figure 13 Track and Flash concept diseases ectcn 2nd ceo quida oer relevo c ysaated xo Pe oC uE hori a eti dioe pog ars 37 Figure 14 Track and Flash device concept naan enseennnnenreennnnenseennnnenseennnneenseennnns 37 Figure 15 Mechanical technology srcascscarcnccrsnncnasmsnaioharnierseeccensaeensanneiersantend o aa aG 38 Figure 16 Electronic Optical sensing 10 nnunnnnnseernneeenennnnnrernneeen
78. rged DDRD amp BV 3 PORTD BV 3 Use Step and Flash mode Switch DDRD BV 4 PORTD BV 4 Use Trigger Flash DDRD amp BV 5 PORTD BV 5 Use Safety Switch DDRD BV 6 PORTD BV 6 Use Safety Indication DDRD BV 7 PORTD BV 7 Use Device is not ready Indication j lMIIIIII Sensor AAN bit Sensor event unsigned int time1 time2 Sensor_report_reset reset all refer Master Thesis 6 1 2 Step 4 flow chart no 7 TwinEye_report read the sensor refer Master Thesis 6 4 flow chart no 9 if g fTwinEyeReport 1 TwinEye_report read cycle finished g fTwinEyeReport 0 TwinEye_report can be read in next read cycle deltaX_stored g_ssTwinEyeDeltax deltaX report stored Master Thesis 6 1 2 Step 4 deltaY_stored g_ssTwinEyeDeltaY deltaY report stored Master Thesis 6 1 2 Step 4 DisplacementX_LEDs DisplacementX_LEDs deltaX_stored deltaX added to the present value of X displacement Master Thesis 6 1 2 Step 4 DisplacementY LEDs DisplacementY LEDs deltaY stored deltaY added to the present value of Y displacement Master Thesis 6 1 2 Step 4 PORTC LSB DisplacementX_LEDs LSB display PORTA MSB DisplacementX_LEDs MSB display lMIIIMIITIIITIII Refer Master Thesis 6 4 flow chart no 9 if DisplacementX_LEDs 0x007F predefine count distance travelled by sensor while bit is clear PIND 2 Microcontroller Acknowledge capacito
79. s are being generated at equal distances travelled by the sensor due to the limited en ergy generated by the flash modules available the overlapping of flashes could not be validated with the means of a thermal camera iv Koninklijke Philips Electronics N V 2009 Unclassified PR TN 2009 00597 Koninklijke Philips Electronics N V 2009 5 PR TN 2009 00597 Unclassified Contents Track and Flash for Photoepilation Using Optical Displacement Sensing i d 2 PATO GIG NO acti seesce te A 8 Hair REMOVAL c 10 Zale Anton Ol FIA METTI 10 2 On 11 odes AEGON OL 13 2 2 Methods to Remove Hair nana oaneeennnnenreennnnrenseennnrervennnnenseennnnnenseens 14 Rel DOPO e e E 14 222 oli inver srsveerne tre biters drink sesenitbornsnharetants nabije biteireetnateins itn tikntdiderinai diend 14 ay if o 1 0 F211 0 En 16 3 1 Photochemical Damage cccccssccccssececceeseeccseseeeceeseeeseeeecssageeessageeessaeeesssaeeesess 17 3 2 Thotomechanical Damage cri suncscrsicisdncesadcdewatiansvactcs aivaeind enden hdd ekain dae 17 3 3 Photothermal Damage u anunnnennennnrenennnseneennnensennenrennnsenenensensennnens ennen 17 3 3 1 Selective Photothermolysis annua annneeennennnnereneeenennnerrnenevennnnnens 18 3 4 Melanin and Light Interaction nanus nanus rereennnen vennen vennneenvennnen vennen 19 90 WIL OUWE IO o E mo omm 23 3 5 1 Light Sources for Hair Remo
80. s for pro tection and acts as anti friction layer between two skin surfaces or skin and any other surface e g a moving arm rubbing against the body 1 2 The hair can be divided into two parts the root and the shaft The hair part outside of the skin is called shaft The root part of the hair is in the skin dermis as shown in fig 1 A pouch like structure called follicle surrounds the hair root The base of the hair root is in the shape of a bulb The centre of the bulb is Shaft Sebaceous glands Epidermis Dermis Follicle Matrix Papilla Arrector pili muscle Figure 1 Anatomy of hair 24 10 Koninklijke Philips Electronics N V 2009 Unclassified PR TN 2009 00597 called papilla The papilla is surrounded by the matrix The papilla is fed by very small blood vessels which bring food and oxygen to it and take wastes away The papilla is highly sensitive to hormones New hair material is formed out of specialized skin cells of the hair matrix The cells in the matrix divide The newly divided hair cells push the previous cells up The cells which move upwards die slowly forming the hard hair shaft The sebaceous glands shown in fig 1 are usually attached to the hair follicles and secrete an oily matter sebum in the hair follicles to lubricate the skin and the hair 1 2 Melanin The colour of our hair and the skin are determined by pigments produced in cells which are called melanocytes Melanocy
81. sec Figure 55 Sensor counts at different velocity 90 Koninklijke Philips Electronics N V 2009 Unclassified PR TN 2009 00597 6 3 Displacement Triggering Flashes Implementation 3 A flash lamp module is added to the mechanical setup in order to mimic Track and Flash The aim is to trigger the flash when the sensor has travelled a fixed distance on the mechanical setup The distance travelled is set by calculating the circumfer ence of the circular path followed by the sensor on the rotating disc Based on this distance travelled flashes are generated The energy radiated with every flash heats up the disc The hot spots on the disk can be viewed by using a thermal camera The expected result is that by suitably triggering the flashes they will overlap on the disc User Input femme User interface femme User Feedback m uk pun en ui L c3 Co a Figure 56 Implementation of Track and Flash with Hamamatsu flash lamp module 6 3 1 Hardware A commercially available Hamamatsu xenon flash lamp module model no L9455 fig 57 has been attached to the mechanical test bench as shown in fig 61 Koninklijke Philips Electronics N V 2009 9 PR TN 2009 00597 Unclassified Figure 57 Hamamatsu xenon flash lamp module It has a flash rate upto 530Hz and emits light with wavelengths between 185nm and 2000nm 9 Figure 58 Pin diagram of the Hamamatsu xenon flash lamp modu
82. shedding of the hair fibre the hair follicle remains empty This phase has been named kenogen 2 Figure 4 Hair growth cycle 25 Koninklijke Philips Electronics N V 2009 13 2 2 2 2 1 2 2 2 PR TN 2009 00597 Unclassified Fig 4 represents the hair growth cycle starting with the anagen phase which is the growing phase to the telogen phase which is the end of the old hair and starting of the new hair 2 Methods to Remove Hair Hair styles or preference for hairless skin are influenced by the culture society or from the entertainment world From ancient time to now different methods have been used to remove unwanted hair from the body As technology devel oped more advanced and sophisticated methods and related devices became available Each method has its own advantages and drawbacks Parameters to be considered for the different methods are the time needed for the treatment its efficiency in terms of whether hair removal is temporary or permanent and side effects like skin irritation Hair removal methods can be categorised in terms of removing hair from above the skin or below the skin Depilation Depilation removes only that part of the hair that is outside of the skin surface Since the depilation method removes only part of the hair one has to repeat it frequently 1 Shaving is the most common example of depilation With a sharp blade it cuts the hair just above the uppermost skin layer Chemi
83. shows a master device connected with multiple slave devices The three lines MOSI MISO and SCLK are common for all devices only the SS Slave Select line is connected individually to each slave device Koninklijke Philips Electronics N V 2009 47 PR TN 2009 00597 Unclassified Micro C Maste Lo Figure 23 Master and slave connection Fig 24 shows a block diagram of the shift register in the master and the slave The system is single buffered in the transmit direction and double buffered in the receive direction Master and slave devices put data on the data register SPDR Now with each clock cycle the MSB bit of each register enters into the LSB bit of the other device s register With each clock cycle a new bit comes into each LSB bit and the previous bit shifts to the left direction At the end of 8 clock cycles 1 byte has been exchanged The SPI can also be configured to start communication with the LSB instead of the MSB After the end of the communication the SPI Interrupt Flag SPIF gets set in the SPI Status Register SPSR These bytes are copied into the receive buffer These bytes must be read before the end of the next transmission otherwise new data will overwrite the previous data and the previous data will be lost 17 18 48 Koninklijke Philips Electronics N V 2009 Unclassified PR TN 2009 00597 Clock Generator SPI Master Shift Direction Figure 24 SPI shift registers Using the S
84. sor microcontroller power supply and Hamamatsu flash lamp module Koninklijke Philips Electronics N V 2009 Unclassified PR TN 2009 00597 6 3 2 Software TwinEye Hamamastuflashmodule c The Hamamastu flash lamp module needs trigger pulses from the microcontrol ler for generating flashes The software generated trigger pulses from the pin D1 of the microcontroller are supplied to the pin 5 of the flash lamp module at fixed distances travelled by the sensor SPI configuration Active sensor Read and Store sensor displacement Is count reach 0x007F Yes Trigger flash Reset counter Flow Chart 8 Twin Eye Laser Sensor with Hamamastu flash lamp module Koninklijke Philips Electronics N V 2009 95 PR TN 2009 00597 Unclassified SPI configuration see Step 2 of the implementation 1 Active sensor see Step 3 of the Implementation 1 Read and Store displacement report See Step 4 of the Implementation 1 Count An actual device using the Track and Flash concept has to flash e g at every 8mm travelled by the sensor but here in the prototype model a predefined number of counts between flashes has been selected such that overlapping flashes are expected on the rotating disc Max 189ms N 10s or more La as d Figure 63 Pulse Width Modulation Trigger flash The trigger signal is sent by the microcontroller when the counter reachs the predefined number of counts The software c
85. sorption around 2000nm Melanin has a decreasing graph of absorption It absorbs more light at shorter wavelength and absorption is decreasing as the wavelength is getting longer An interesting property of melanin is that starting around 600nm to 1200nm melanin has higher absorbing region than other chromophores i e water and haemoglobin In this region of its absorption band melanin becomes a useful tool for cosmetic applications 1 Pulse duration The pulse width of the electromagnetic radiation has to provide maximum contrast of heating of the target versus surrounding tissue 1 The pulse duration is related to the generation of heat in the tissue Long pulse duration transfers more energy into the tissue than short pulses Because of the greater amount of energy long pulse duration generates more heat into the tissue The pulse duration that confines most of the heat generated to the target tissue is called thermal relaxation time The thermal relaxation time for hair removal is estimated to be between 10ms to 100ms Pulse duration greater than the thermal relaxation time is called thermal damage time TDM Pulse duration with thermal damage time damages also tissue surrounding the tar geted tissue 1 Fluence rate The fluence rate is the amount of energy striking on the targeted area at a time resulting in the generation of heat Fluence of the pulse has to be sufficient to provide the desired effect 1 Melanin and Light In
86. teraction The interaction of light with the skin is a complicated process Skin is a tissue that has reflecting scattering and absorbing optical properties It has a higher reflective index than the air which causes partial reflection of the light when hitting the skin surface while the remaining part penetrates into the skin Light propagation within the skin depends on the scattering and the absorbing proper Koninklijke Philips Electronics N V 2009 19 PR TN 2009 00597 Unclassified ties of the various compartments like cells organelles etc Multiple scattering and absorption decreases the intensity of the light propagating deep into the skin This absorption transforms light energy into other forms of energy mostly heat A chromophore is a molecule which absorbs light There are many kinds of chromophores in the human body e g haemoglobin bilirubin carotenoids porphyrins and melanin These chromophores have particular absorbing bands in the electromagnetic spectrum where they react while interacting with the light 1 Melanin in the hair causes the colour of hair like melanin in the epidermis layer of the skin causes the colour of the skin For the hair removing concept using the selective photothermolysis principle melanin in the hair follicle is the main target This can be done by targeting the absorbing region of melanin and avoiding the absorbing regions of other chromophores Damaging the target tissue with or without dist
87. tes produce a chemical pigment called melanin This chemical compound that reflects certain wavelengths of visible light determines the colour of the hair and the skin Fig 2 shows a micro scopic view of the melanocytes in the skin which are responsible for the skin colour These melanocytes are present only in the epidermis layer of the skin The skin layer below the epidermis is called dermis It has no melanocytes cells except in the hair in the matrix close to the dermal papilla which is responsible for the hair colour 1 2 Melanocyte Melanin Epidermis Figure 2 Pigmented cells in skin 26 Koninklijke Philips Electronics N V 2009 11 PR TN 2009 00597 Unclassified The melanin produced in the matrix is also present in the hair shaft There are two main pigments found in the human hair Eumelanin and Pheomelanin Eumelanin has an oval or an elliptical shape It gives colour to brown or black hair and is the dark pigment A higher concentration of Eumelanin causes darker hair Pheomelanin produces the colour in blonde or red hair The higher the concentration of Pheomelanin the lighter the hair Unlike Eumelanin Pheomelanin is smaller partly oval and has a rod shape White hair contains no melanin at all and gray hair contains only a few melanin granules The amount and density of the melanin in the shaft determines the exact colour of the hair The colour shape and thickness are determined by genetics 1 2 There are
88. track on steps Light penetrates into the skin in the shape of a cone There is less intensity of light at the border part which is not sufficient to gener Koninklijke Philips Electronics N V 2009 35 4 3 4 3 1 4 3 2 PR TN 2009 00597 Unclassified ate enough heat for hair follicles see fig 9 If no overlap at the border area is achieved then in the area left out in between hair follicles are unaffected For larger body parts it may be difficult to keep track on each step User support may be desirable Power for flashes SatinLux works using rechargeable batteries these batter ies must be charged before using the device As mentioned earlier a single leg needs 320 380 flashes and approximately 30 minutes of time A fully charged battery offers 160 flashes at maximum intensity level level 5 which means approximately 15 minutes Improved power handling is desirable The above points indicate opportunities for a new concept for a faster and more sophisticated device which should keep track on treatment consume less time and give the user feedback in a more sophisticated way Such a Track and Flash concept is described in the following Track and Flash Concept The device is tracked across the skin and at fixed intervals of displacement flashes are released automatically without lifting the device This concept has the vision to make a device which works like shaving razor which removes hair but here it stops hai
89. troller and its interfaces with other devices are shown in fig 25 The Processor core is the central processing unit CPU of the microcontroller It contains the arithmetic logic unit ALU registers and the control unit The ALU performs different operations e g addition subtraction incrementing and gives output or stores data into the registers 18 There are two types of memory program memory and data memory It can be temporary use memory RAM or permanent store memory ROM Digital I O Ports input output Ports interface with other sources or systems Most microcontrollers have Analog Digital A D converters connected to the Ports which increases the microcontroller s functionality 18 A Timer Counter is used for timestamp events to measure intervals or count events Many microcontrollers have PWM generators Pulse Width Modulation which can be used for the applications which are controlled by pulses A typical use of PWM is to drive PWM motors 18 Interface modules are used for interfacing with external device Any microcon troller has at least one interface module mainly SPI interface which can be connected to a computer and programs can be downloaded into the memory of the microcontroller 18 Interrupts are used to pause the running program and react on external or internal events 18 Microcontroller software can be written in the assembly language or in a high level language e g C BASIC There
90. trolmegisler SPOEC 2 T zomerse E Re 76 Table 7 SPI status regisler SPSR 21 iicet iie Pianos a onem tua e reu Mado 77 Table s Pinunetonalil RT mS 92 110 Koninklijke Philips Electronics N V 2009 Unclassified PR TN 2009 00597 Flow Charts Flow Chart 1 Polling mode Master device configuration flow chart nennen 50 Flow Chart 2 Slave device configuration flow chart uns neennnn enn eennnernseennnsnens vennen 51 Flow Chart 3 Interrupt controlled Master device flow chart nnen oneens enenenenennen 53 Flow Chart 4 Interrupt controlled Slave device flow chart anneer enen enn ennnneneennen 54 Flow Ghiart SAVR ere anos Elle mer tienden eenn case ees eames 72 Fow OnartS SPLCOMIGUALON e Cu H 75 Flow Chart 7 Displacement report and store u nanuns ennn ennnnrenneennneereennnnneenseennnneens vennen 79 Flow Chart 8 Twin Eye Laser Sensor with Hamamastu flash lamp module 95 Flow Chart 9 Twin Eye Laser Sensor with TI Evaluation Module 102 Koninklijke Philips Electronics N V 2009 111 PR TN 2009 00597 Unclassified A C Code A 1 TwinEye c Master Thesis Track and Flash Master Thesis chapter 6 1 Displacement Sensing Implementation 1 Master Thesis chapter 6 2 Displacement Sensing in the Mechanical Setup Implementation 2 This program makes use of confidential header files and functions include lt string h gt
91. urbing surrounding tissue depends on the pulse dura tion Temporary or permanent removal of hair depends on the fluence rate 1 2 Selection of wavelength Melanin is a natural chromophore present in the hair shaft and the hair matrix As shown in fig 5 melanin has a wide waveband of absorption from visible light to the near infrared region Major competitor chromophores to the hair melanin are blood water and epidermal melanin Using the absorption spectrum shown in fig 5 one can estimate the optimum absorption band of the targeted hair melanin taking into account competitive chromophore absorption bands Addi tional parameters taken into consideration while selecting the wavelength is the location of the targeted melanin with respect to competitive targets and the concentration of the melanin 1 2 Melanin in the hair lies between 2 mm to 5 mm depth in the skin 3 So the penetration length of light source for targeting hair melanin should be selected between these depths Deep selective heating of the hair shaft and the heavily 20 Koninklijke Philips Electronics N V 2009 Unclassified PR TN 2009 00597 pigmented matrix are possible in the region of 600 1100nm 2 Most lasers successfully utilised for hair removal emit radiation with wavelengths avoiding the major absorption peaks of haemoglobin and water As shown in fig 5 the ruby laser can be most suitable for hair removing concept because it has a wavelength of a 694nm
92. uster Motor Rotating disc N Ne t N t Flash Adjustable flash Adjustable senso i stand stand 1 d N r QOL e ee Er a ge Sensol Sensor housing Figure 27 Test bench The rotating disk is made of plastic material The rotating speed of the motor is controlled by LabVeiw software through the PC connected to it Sensor and flash positions can be adjusted 58 Koninklijke Philips Electronics N V 2009 Unclassified PR TN 2009 00597 A LabView program shown in fig 28 controls the motor parameters accelera tion time duration of rotation deceleration set point plate rotation in mm second The actual speed is obtained as feedback from the motor TF i Front Panel SEE dct ES Je In ot vsicoton Font elle C J 100000 N wij A i IM Tl P CE C S E Ej N m i x Z E x z x x I F g x x x x rc x x x g z Figure 28 LabView program for mechanical setup Koninklijke Philips Electronics N V 2009 59 6 1 6 1 1 PR TN 2009 00597 Unclassified Implementation of Track and Flash Displacement Sensing Implementation 1 The first task to be solved is to implement Displacement Sensing and to check its functionality and compatibility with the Track and Flash concept For this purpose functions are implemented in the control module to read out displace ment values reported by the Displacement Sensing module fig 29
93. val seri reisinin eennnnerenseeenennnnens 26 3 6 Limitations and Side Effects of Photoepilation unseren eeenennneeen enen 29 Consumer Device GONCEPIS nnn nen renderende a eenden erdee a A 30 4 1 Point of Care and Home Applications Usability Safety 30 LM ole e a a 33 DN 33 Bee DISCUSSION reen nat neben 35 4 3 Track and Flash aan anennennennen vennen vanen vennen eneen ennenrennenvennenvennenvnnnnnnn 36 Beale ONCE EN m 36 4 3 2 How to Implement the Track and Flash Concepts 36 Key Components for Track and Flash e eceeeeee eee Leeeeee eer ee een 42 5 1 Displacement Sensor cccccccccsseseseeeeeeeaeeeeeeceeeeeeseaeesseeeeeeeesseeeeeeeeeesssaaaeeeseeeeeesaaas 42 5 1 1 Twin Eye Laser Sensor anne ennnnnnnseernnerensnnnnnenneeeenennnnerrnsnrensnnnnens 43 5 1 2 Serial Peripheral Interface SPI aanne enennnnnerennneeenensnernnneeeennnnens 47 2 MIGOCON KOMOP ERNEUT Tm 55 Sd OTKSOO Evaluation BORE seci ketenen 57 O ENI cH gqciorT E 58 Implementation of Track and Flash eeeeeee eese eee eee eren nnns 60 Koninklijke Philips Electronics N V 2009 Unclassified PR TN 2009 00597 6 1 Displacement Sensing Implementation 1 annsennnnnnerernneeennnnneennn eenen 60 Okis TAAVOWANC navenante dte ates a e nete eo awe edewenenen
94. verlap between two adjacent steps is necessary because there is less intensity at the border area Hair follicles in the area left out between two steps will remain unaffected To avoid that the user must stay concentrated during the treatment Optimal results cannot be obtained with a single session The anagen phase of the hair growth cycle is the only phase for the effective treatment but during treatment hairs in the treatment area are usually in different stages of the cycle of hair growth To treat all hairs successfully one has to repeat this treatment Clinical trials have shown that repetition of treatment every 2 weeks gives opti mal results Discussion In the following some characteristics of SatinLux with Step and Flash concept are discussed that indicate potential areas for product improvements Number of flashes and treatment time One of the flashes can cover 3cm area of the body As stated in the manual it takes 25 flashes per armpit and it takes approximately 3 minutes of treatment time The entire bikini area needs approximately 90 flashes and takes 10 minutes This time is appropriate for a small area and it will not be difficult for the user to spend 10 minutes time every two weeks But as to larger areas like one full leg it needs 320 380 flashes and approximately 30 minutes of treatment time This points to an opportunity for improving system performance to reduce the time of treatment on larger body areas Keep
95. xt read cycle deltaX stored g ssTwinEyeDeltaX deltaX report stored deltaY stored g ssTwinEyeDeltaY deltaY report stored DisplacementX LEDs DisplacementX LEDs deltaX stored display on LEDs DisplacementY LEDs DisplacementY LEDs deltaY stored display on LEDs PORTC LSB DisplacementX LEDs LSB display PORTA MSB DisplacementX LEDs MSB display j j int main void sensor configuration SPI configuration Refer Master Thesis 6 1 2 step 3 flow chart no 6 Sensor Initialisation configuration Master Thesis 6 1 2 Step 3 with PLN2031 sensor product specification TwinEye init TwinEye cpi for Refer Master Thesis 6 1 2 step 2 to 4 flow chart no 7 Sensor_event read store and display Koninklijke Philips Electronics N V 2009 113 PR TN 2009 00597 Unclassified A 2 TwinEye Hamamatsuflashmodule c Master Thesis Track and Flash Master Thesis chapter 6 3 Displacement Triggering Flashes Implementation 3 This program makes use of confidential header files and functions include lt string h gt define AVRGCC include C sensorprogram6 config h include C sensorprogram6 mouse_wired_philips_drv h include C sensorprogram6 TwinEye_api h define Sensor_report_reset Sensor report 0 0 Sensor report 1 0 Sensor report 2 0 Sensor report 3 0 Sensor report 4 0 Sensor report 5 0 unsigned int DisplacementX LEDs deltaX stor
96. y reflecting mirror like surfaces because usually some dust particles are there on the surface and this sensor is sensitive enough to work with this condition 13 This sensor is made compact 6 8mm x 6 8mm x 3 85mm in size by the use of oystem in Package SiP technologies in its construction An Application opecific Integrated Circuit ASIC is mounted on a lead frame It contains digital processor filters modulators communication ports The laser sources and photo detectors are also mounted directly on the lead frame It has a cover which has pre mounted beam forming lenses which reduce all other extra optics necessary for focusing the beam on the surface 13 46 Koninklijke Philips Electronics N V 2009 Unclassified PR TN 2009 00597 Figure 22 Twin Eye Laser Sensor without lens 16 Before the Twin Eye Laser Sensor can start sampling data certain initialisation steps need to be performed using the microcontroller in order to define initial operating parameters for the sensor Serial Peripheral Interface SPI SPI communication uses 4 wires for communication MOSI Master Out Slave In the master puts data on this line that goes as an input to the slave MISO Master In Slave Out the slave puts data on this line that data goes as input to the master device SCLK Shift Clock using this line the master provides a clock to the slave SS Slave Select the master uses this for selecting the slave device Fig 23
97. y switch is pressed The role of this switch is described in the software part Pin D7 is connected with the LED the function of it is described in the software part Koninklijke Philips Electronics N V 2009 101 PR TN 2009 00597 Unclassified 6 4 2 Software TwinEye Tlflashmodule c Below is the flow chart of Track and Flash mode program with safety features m Wait for Active sensor saftey switch Configuration pressed Yes LED Indication Saftey On iS Count Ox0005 Start charging Read Store and display sensor displacement Start charging iel io Is Step and Flash mode switch trigger LED On Capacitor Capacitor is not fully charged Charged E Yes Is Stop Charging Ee Count Ox007F LED Off PO ue Capacitor is charged dis on 7 f Trigger Flash Reset Counter Flow Chart 9 Twin Eye Laser Sensor with TI Evaluation Module SPI configuration See Step 2 of the Implementation 1 102 Koninklijke Philips Electronics N V 2009 Unclassified PR TN 2009 00597 Active sensor See Step 3 of the Implementation 1 Read and Store displacement report See Step 4 of the Implementation 1 Explanation of the flow chart As shown in the flowchart no 9 the system performs a safety check by confirm ing the continuous pushed down status of the safety button This safe state is displayed by illuminating the system safety LED As a feedback to the user the safety LED must be

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