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Sensor System for Infrared Spectroscopy - Introduction - Pro-4-Pro

1. Germany and other countries LASER COMPONENTS GmbH Phone 49 8142 2864 0 Fax 49 8142 2864 11 info lasercomponents com Great Britain LASER COMPONENTS UK Ltd Phone 44 1245 491 499 Fax 44 1245 491 801 info lasercomponents co uk France LASER COMPONENTS S A S Phone 33 1 3959 5225 Fax 33 1 3959 5350 info lasercomponents fr G HSINH esl NOILVWaOHNI Aa V 13leldOeld NOILOJ ONd 31ONY IVIN3GHNOO Q ELSIVOS sosi vO sooo 20000 2 mE V UM aus IW 992 182 wwo x 10 wr wma 899701 SYOSNSS 1VO 11 25 LON ___ 8 ON J 83OISIWN3HL 10 el Hoa 96 WbiSIVHOTO Cl ON SC Il viva vc OL 2 MID TXid tc 6 Xioqiovd cc SvISNISN 8 ON IC IMVIS3WVNH 210 ON 06 9 XOIN 61 S ___ 88 p Pea Zt 051 ON 91 v3OISWNSHL Z ON SI SWIG OLD __ 9 ONNId SNOILONf Nid 91412345 ASIMASHLO 5859131 ASJ 90 12 70 Wad JLON 993 3301833 553 20
2. COOLER cooler on by clicking on the Cooler switch The Cooler Control indicator will move towards the set point and the Cooler Power indicator will show the percentage of full power being supplied to the cooler If the software senses a cooler error such as insufficient heatsinking the cooler power will be shut down and the Cooler Error light illuminated Correct the problem and turn the cooler back on to reset the error e CALIBRATION To calibrate the array from the main screen press the calibrate array button This brings up the calibration window Calibrate vi x User Settings t Offset Detector Bias Integration Time Suppress Global Find Bad 20 12 0 200 0 jie Messages Skim Pixels 1 5 i 10 001 8 3 OFF 100 pe Size 3 10 9 0 1 0m 8 8 0 Presets 085 E no PbS Rect PbS Sq E 6 07 10 0u SET A A A al ee ee Pe PbSe Rect PbSe Sq 105 8 0 V 5 0 25 50 75 100 125 150 175 200 225 25 Pixel DAC Voltages Vlow E Vhigh 1 610 f SUD 21717135 12171522 8151111 121 3 2214 78 1158 171 8112 21512115 87171735 23717117 1 976 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 50 0 1 l l l l l 1 l 1 l l 1 0 10 20 30 40 50 60
3. Wad Nid OEZ HION3T EB d ER 7 EJ SNOISNA3NIG ANILAO TVOINVHO3IN 403 134 5 445 SALON 10 10 01 Wad JWLOMCNI OLSIIvI3d NII 8 0 2 69029 V NS S Dos S 7 00 810 X8Z 9073 001 007 008 C90 vl l tl 016 812 9 S v C ELl SCC jOv4alns ONILNNOW 8 092 100171 JNY Id AVlal V JANLAIdY OFS SOL 04 X OSL 005 0001 JANA 012 052 SNOISIA33 133HS 335 OOS 6 S31ON 133HS 335 LASER CalSensors EONIBONENTS 256 Element PbSe Multiolexed Array Performance Parameter 00000000 00000000 Pixel width 40 microns pixel height 450 microns Element Size i and pixel pitch 50 microns PeakDetectvity _________________ 7 5 1x10 W 4 C Response Uniformity pixel to pixel E1596 of array signal mean PbSe Integration Range 1 Ofmsto 100ms on board Pixel Clock 1 1 Linearity poA Pixel Operability YB Detector Rise Time KIS Input Power Requirement ____________ 12 VDC main 5VDC 1 5A cooler Detector Array Input Circuitry Charge Well Sample amp Hold 1 13 MUX Out 1 01 21 _ 10 Detector 0256 ye Bias D256 02
4. rd Number 256 Element Data Acquisition Array Infrared Arra m Communications 2 i P stor stor Cooler Cooler Cooler Control Power Clear 3500 String 2 25 The First 400 characters typed here will be written T 2 3000 20 to the non volatile memory the USB board with the Write button and the memory content is displayed here with the Read command 2500 2000 a Set OOS A Wu n 10 20 30 40 50 60 70 80 90 220 230 240 255 1500 5 eee LAddr Ef PixelData 193 23 Read Write 1000 Bad Pixels Software Settings EXIT Reference Gain Correction k 500 ad Averages ad alibrate Array eA Dl n Dd J cu Write Data to csv 3 Settings to board memory Control Board Information Cooler Vid Serial Number Test Array ot Check Sum 0706 CSI 8073 9 08 Germany and other countries LASER COMPONENTS GmbH Phone 49 8142 2864 0 Fax 49 8142 2864 11 info lasercomponents com Great Britain LASER COMPONENTS UK Ltd Phone 44 1245 491 499 Fax 44 1245 491 801 info lasercomponents co uk France LASER COMPONENTS S A S Phone 33 1 3959 5225 Fax 33 1 3959 5350 info lasercomponents fr EST ARRAY This function facilitates testing of the array under known input conditions After the button is pressed you will be asked for the part serial number and other
5. on the Windows Update Web site with Your permission Read our privacy policy Windows connect to Windows Update to search for software CO Yes this time only CO res now and ever time connect a device 5 this time Click to continue 3 Choose Install from a list or specific location Advanced and click Next Found New Hardware Wizard This Wizard helps you install software for ADIC Linear Array Controller 93 your hardware came with an installation CD Cue floppy disk insert it now What vau want the wizard to do CO Install the software automatically Recommended Install fram a list or specific location Advanced Click to continue lt Back Next gt Cancel CSI 8073 9 08 Germany and other countries LASER COMPONENTS GmbH Phone 49 8142 2864 0 Fax 49 8142 2864 11 info lasercomponents com Great Britain LASER COMPONENTS UK Ltd Phone 44 1245 491 499 Fax 44 1245 491 801 info lasercomponents co uk France LASER COMPONENTS S A S Phone 33 1 3959 5225 Fax 33 1 3959 5350 info lasercomponents fr 4 Select Search for the best driver in these locations and check Include this location in the search Browse to C Program Files XCSI256v4 Drivers directory and click NEXT Found Mew Hardware Wizard Please choose your search and installation options Search far the best driver in these loc
6. Germany and other countries LASER COMPONENTS GmbH Phone 49 8142 2864 0 Fax 49 8142 2864 11 info lasercomponents com Great Britain LASER COMPONENTS UK Ltd Phone 44 1245 491 499 Fax 44 1245 491 801 info lasercomponents co uk France LASER COMPONENTS S A S Phone 33 1 3959 5225 Fax 33 1 3959 5350 info lasercomponents fr Cal Sensors 256 Element Array Development System User s Manual 1 Getting Started The purpose of the development system is to provide our customers with a convenient method to gain experience using the Cal Sensors 256 Element Multiplexed Array The components of the development system can then be used within the customer s system saving development time and expense The development system consists of the following items 1 256 Element Array 2 USB Interface Electronics Board 3 Copper mounting block 4 Heatsink with integrated fan1 5 USB cable 6 Power supply module 12V 5V 4A 7 Cal Sensors Array Controller Software and USB driver Before You Start System Precautions The development system has been designed to be robust enough to be used in a laboratory environment however the following precautions must be observed m Both the USB Interface Electronics Board and the array itself are ESD sensitive Please exercise typical ESD handling precautions Use a grounded outlet with the power supply module m thermal design of this system is not intended to be opera
7. Interface Electronics The task of the inter face electronics is to s implify the interface between the controlling computer and th e sensor and has been implemented on a small board that plugs directly into the sensor header and provides connections for the USB interface as well as system and thermoelectric cooler power a em iam gt GS HBR gt Figure 5 Interface Electronics The following functions are provided by the interface electronics Sensor detector and multiplexer IC control and interface hermoelectric cooler control e Digitization of the analog detector signal output stream USB command based interface o Analog conversion of digital control voltages o Command based interface structure for simple software integration The sensor IC requires numerous timing signals to operate microcontroller based architecture has been selected to implement the required functions This makes generation of the timing signals simple and easily modified thr ough th e f irmware int erface por t All controls oftware as thes alibration coefficients ar e s tored in on board non volatile m emory T his als o f acilitates r estoration of the s ensor coefficients through the startup sequence so the process can be transparent to the spectroscopic system The thermal stability of the photoconductive array is critical f
8. LASER CalSensors COMPONENTS Sensor System for Infrared Spectroscopy Introduction Outline of the Problem Infrared s pectroscopy particularly inthe ne ar and mid infrared region is an important field th at requires specialized s ensors T he ind ustry c ontinues to grow with ne w applications developing as the s ensor technology becomes available In many cases the science required for spectroscopic analysis is understood and th e implementation waits only for the s upporting technology to be d eveloped Trends are as always towards smaller lower cost systems with improved performance The mplementation of s uchas pectroscopic s ystem invol ves s everal s ubsystems eas of specialization e Op tics o The fundamental purpose of the optical component in a spectroscopic system is to disperse the optical input spatially by wavelength T he geometry of this dispersive aspect needs to be compatible with the sensor array being used e Sens or The sensor is the component which converts an optical input to an electrical output T he sensor typically incorporates an array of detector elements with some low level multiplexing and biasing electronics In addition to the g eometric design of the detector elements many other parameters need t obe c onsidered including o perating tem perature s pectral sensitivity s tability r esponsivity nois e and s peed both r eadout s peed a nd detec tor response s peed O bviously th
9. PbS Pb Sehaveal ong hi story of develop ment and hav e take n a dvantage of a dvancesi n manufacturing techniq ues to continu eto be imp ortant dete ctors fo r infrare d sen sing Advances photolithography in the 19 60s provided the method ology to creat e arrays of p hotoconductive materials thereby a dvancing the n umber of appl ications avail able to the se dete ctors particularly in the area of spectroscopy Germany and other countries LASER COMPONENTS GmbH Phone 49 8142 2864 0 Fax 49 8142 2864 11 info lasercomponents com Great Britain LASER COMPONENTS UK Ltd Phone 44 1245 491 499 Fax 44 1245 491 801 info lasercomponents co uk France LASER COMPONENTS S A S Phone 33 1 3959 5225 Fax 33 1 3959 5350 info lasercomponents fr Issues and Solutions Principals of photoconductivity Photoconductors are esse ntially resistors whose conductivity changes with in cident photons A photon with energy greater than th e material s band gap energy is absorbed in the ph otoconductive material t o produce electron hole pairs which increases the conductivity of the mate rial To measure the in cident radiation a simple voltage divider bias circuit is typically used The current through the load resistor and therfore the voltage across the load resistor varies with incident radiation In practice the photoconductive change is small com pared to the bulk sistance of the materi al so differe ntiating the signal ca n be d
10. e Generation of all required timing and control signals Power connection Power to the Interface Electronics Board is supplied through a six pin connector Power supplied to this board also supplies power to the detector array and the thermoelectric cooler Connector Pin Assignment Pin 1 BLACK Wire Ground Return for 12V power 100mA Pin 2 RED Wire 12VDC 100mA System Power Pin 3 amp 4 BLUE Wire Ground Return for TEC Power approx 2A Pin 5 amp 6 YELLOW Wire 5VDC 0 2 Amps TEC Power Note that the Ground Returns for both 12 power and the TE power pins 1 3 and 4 must be connected together at the system common ground point otherwise damage may result to the controller board CSI 8085 8 08 Germany and other countries LASER COMPONENTS GmbH Phone 49 8142 2864 0 Fax 49 8142 2864 11 info lasercomponents com Great Britain LASER COMPONENTS UK Ltd Phone 44 1245 491 499 Fax 44 1245 491 801 info lasercomponents co uk France LASER COMPONENTS S A S Phone 33 1 3959 5225 Fax 33 1 3959 5350 info lasercomponents fr USB Connector e Figure 4 Interface Board Connectors Interface Electronics Board Voltage Sources Precision Voltage Sources e Figure 5 Interface Board Block Diagram CSI 8085 8 08 Germany and other countries LASER COMPONENTS GmbH Phone 449 8142 2864 0 Fax 49 8142 2864 11 info lasercomponents com Great Britain LASER COMPONENTS UK Ltd Phone 44 1245
11. Phone 33 1 3959 5225 Fax 33 1 3959 5350 info lasercomponents fr 4 The CSI256 application program is now installed It uses the ADICLib 256R4A dll to interface with the array which is installed in the standard Windows System or System32 directory 5 The Cal Sensors 256 Array interface board uses a standard Windows Dynamic Link Library dll to access all of the operational functions This means that custom software can be developed in a variety of languages An application written with LabView is included to demonstrate many of the array functions The installation media also includes a DLL directory with information for using the DLL including a help file that lists all of the DLL functions The DLL directory also includes a copy of the ADICLib 256 4 4 file The first time you use the development system you will need to install the USB drivers To do this follow these instructions 1 With the computer on and the USB cable from the MUX Controller Board disconnected from the computer apply power to the controller board by plugging in the power supply module and then plug the USB cable into the computer 2 The Found New Hardware wizard will pop up requesting to connect to Windows Update Select No not at this time and click NEXT Found Mew Hardware Wizard Welcome to the Found New Hardware wizard Windows will search for current and updated software by looking your computer the hardware installation
12. Tha first piesi START comu out on the ment falling edge afer START FRAME gets clocked in FRAME Readout proceeds with sre coming out o5 inner edge of PEL windowing being used the may Pi Analog iun Pi Pixel Pixel Pixel Pixel Stream ib Pixel 155 ars dran letus 4 5 B T IWR Integration Detail 250 5 min PIXEL CLK PIXEL map be run t ross red nad c ba INT CLK m sus min l START FRAME is checked in by the rising edge af PIXEL The piesi START comes cut on tha rant falling edge afer START FRAME gets clocked in FRAME min eee Analog Pixel Pixel peter In m Pixel Pixel P Pixel Pixel CLK Pixel Stream 8 This diagram fiumei a of a full 256 element array windowing H Being used he pirel may not Be Pinel 0 ___ weld be Pixel 155 id mould count damn Recem diuine Germany and other countries LASER COMPONENTS GmbH Phone 49 8142 2864 0 Fax 49 8142 2864 11 info lasercomponents com Great Britain LASER COMPONENTS UK Ltd Phone 44 1245 491 499 Fax 44 1245 491 801 info lasercomponents co uk France LASER COMPONENTS S A S Phone 33 1 3959 5225 Fax 33 1
13. These g eometries are compatible with most in frared optical systems and provide enough photon collection area to produce reasonable signals Although these geometries do not push the limits of p hotolithographic te chniques with traditional deposition m ethods the p olycrystalline films and substrate surface finishes the topographies make fine photolithography difficult In addition th e films are sen sitive to und ercutting whi ch can occur with ph otolithographic et ching an d in creases the resistance variability in arrays with small geometries lon milling provides a method of delineation with finer detail in these situations 4 and eliminates some of the disadvantages of photolithography Implementation A key to su ccess in producing robust products is t he application of proven processes The balance is between pushing the tech nical envelo pe to in crease pro duct u sefulness and making sure the ap plied technologies are matu re e nough to yield con sistency and reliabil ity in the en d application This is a second generation implementation that refines the initial work done ead salt photoconductive arrays implemented only for spectroscopic applications This second generation implementation enhances the previous design and expands the application base to thermography and thermal imaging with a 40 x 40um pixel option Germany and other countries LASER COMPONENTS GmbH Phone 49 8142 2864 0 Fax 49 8142 2864 11 info lasercomp
14. library dll This manual will first discuss the operation of the array then the operation of the interface board CSI 8085 8 08 Germany and other countries LASER COMPONENTS GmbH Phone 49 8142 2864 0 Fax 49 8142 2864 11 info lasercomponents com Great Britain LASER COMPONENTS UK Ltd Phone 44 1245 491 499 Fax 44 1245 491 801 info lasercomponents co uk France LASER COMPONENTS S A S Phone 33 1 3959 5225 Fax 33 1 3959 5350 info lasercomponents fr Section 2 Cal Sensors 206 Element Array Programming Manual 2 Array Principles of Operation Introduction The array consists of the following items all housed within an industry standard 28 pin package 1 Thermoelectric cooler used for thermal stabilization Note Sufficient heatsinking must be provided to prevent damage to the array 2 Thermistor used to provide feedback to control the temperature of the thermoelectric cooler 3 Multiplexing Interface IC used to condition the array output and multiplex all 256 channels onto a single output line 4 256 Element Photoconductive Infrared Array used to convert infrared photons into an electrical output MUX LI Lines gt Multiplexed Signals Header e Figure 1 Array Functional Block Diagram CSI 8085 8 08 Germany and other countries LASER COMPONENTS GmbH Phone 49 8142 2864 0 Fax 49
15. 20 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 255 Pixel DAC Values Bad Pixels Toggle Current Clear All Bad DAC Values 2 DACData 202 108 Bad Pixels CALIBRATE Adjust the User Settings to their desired values Preset Values may be recalled by pressing one of the Preset buttons Preset values may be set by pressing the SET button and corresponding detector type After the appropriate settings have been selected cover the array and press the Calibrate button The software then cycles through the calibration sequence displaying progress messages assuming Suppress Messages is Off and setting correction values for each pixel Upon completion the DAC voltages for each pixel are displayed in the graph as well as the High and Low voltage range and the Global Skim value if Global Skim was turned on before calibration Bad pixels can be marked in this window as they were in the main window After calibration is finished click OK to return to the main window If the Quick option is selected in the main window by clicking the LED the array will be calibrated with the current settings without calling the calibration window Be sure to cover the array to obtain an accurate calibration CSI 8073 9 08 Germany and other countries LASER COMPONENTS GmbH Phone 49 8142 2864 0 Fax 49 8142 2864 11 info lasercomponents com Great Britain LASER COMPONENTS UK Ltd Phone 44 1245 491 499 F
16. 3959 5350 info lasercomponents fr Cal Sensors 256 Element Multiplexed Array Functional Diagram Global Skim DAC Clock M Bias Reset Int Cap 3 Int Cap 6 USB Interface Board Features amp Specification USB interface to controller Can be controlled by software commands with supplied driver Simple command structure interface 1 On board microcontroller controls all multiplexed array functions Cooler control to set point temperature All multiplexed timing and control voltages Detector bias voltage A D converter control otorage of all control and correction coefficients in no volatile memory Automatic reload at power up 16 bit A D converter at 500k samples sec Efficient high current PWM cooler drive FET requires additional heatsinking oynchronization with A D conversion ensures low noise Simple power requirements 12V 100 mA 4 to 6 volts 01 5 Small size 2 1 x 1 4 x 0 4 E Direct interface to standard 28 pin package 06 09 V1 HW cal lirabs doc Germany and other countries LASER COMPONENTS GmbH Phone 49 8142 2864 0 Fax 49 8142 2864 11 info lasercomponents com Great Britain LASER COMPONENTS UK Ltd Phone 44 1245 491 499 Fax 44 1245 491 801 info lasercomponents co uk France LASER COMPONENTS S A S Phone 33 1 3959 5225 Fax 33 1 3959 5350 info lasercomponents fr LASER CalSensors COMPONENTS 256 Element Array Development System User s Manual CSI 8073 9 08
17. 44 1245 491 499 Fax 44 1245 491 801 info lasercomponents co uk France LASER COMPONENTS S A S Phone 33 1 3959 5225 Fax 33 1 3959 5350 info lasercomponents fr Array Calibration Uncalibrated Qq o 4 4 a e 4 4 Calibrated Pixel Number Figure 1 Effectiveness of Per Pixel Dark Current Subtraction Environmental Sensitivity Wet chemi cally deposite d PbS and PbSe photo conductive films are poly crystalline in structure The materials u sed in their fabri cation p roduce films that are hyg roscopic se nsitive to UV radiatio n an d mechanically fragile The film charact eristics can al so change or be destroyed at hig h te mperature or with condensing moisture The solution is to insure that the components are hermetically maintained in an inert environment Proper selection of t he backfill gas can al so help with the thermal load presented to the thermoelectric cooler Vacuum packaging is also an option but is not required for the rea sonable operating temperatures used by lead salt photoconductors and the complexity is usually avoided Small Geometries Single el ement dete ctors roduced from wet chemically d eposited ph otoconductive films have traditionally b een delin eated by stand ard ph otolithographic techniqu es Cu rrent array g eometries a re typically 40u m x 450um for spe ctroscopic arrays and 40um x 40 um for therm ographic arrays both with inter element gaps of 1 Oum
18. 491 499 Fax 44 1245 491 801 info lasercomponents co uk France LASER COMPONENTS S A S Phone 33 1 3959 5225 Fax 33 1 3959 5350 info lasercomponents fr Cal Sensors 296 Element Array Programming Manual 4 Operation Overview Because of the high level of functional integration contained in the Interface Electronics Board the operation of the array is simply a matter of supplying mechanical connection including heatsinking electrical connection power and USB and then sending the appropriate commands from the host computer Therefore this section is primarily a description of how to implement the software commands Since a standard Windows interface library is provided any standard programming language may be used Cal Sensors provides an application written in National Instruments LabView with the Development System Because of the generic nature of the interface library no particular programming language will be targeted in this section Specific language implementations are shown in the ADIC Library Documentation and that document should be referred to for details on each of the library commands Functions ArrayAdd oaveE2Block ArrayPercentDiff SendAllCoeff ArraySubtract SetConversionRef CloseDevice SetConversionRef_Brd DoCalibrate SetDacGSkim Flux_P SetDacReferences Flux W SetDacReferences GetBoard_Handle SetDacVH GetQuery3 Setintegration HideBadPixels SetMuxSize HideBadPixels Brd SetWellSize MarkBadPi
19. 8142 2864 11 info lasercomponents com Great Britain LASER COMPONENTS UK Ltd Phone 44 1245 491 499 Fax 44 1245 491 801 info lasercomponents co uk France LASER COMPONENTS S A S Phone 33 1 3959 5225 Fax 33 1 3959 5350 info lasercomponents fr Operation A simplified pictorial representation of the array operation is shown in Figure 2 This should be referred to throughout the following discussion Vbias Infrared Detector Energy Photo Cyrrent Instantaneou Charge Well Well Voltage Capacitor All multiplexed Offset ut signals to output Correction m ple And Voltage Hold Time Analog voltage level represents detector ul 3 e Figure 2 Array Operation Summary Each pixel has a bias voltage applied generating a current which is collected in a charge well capacitor The offset current is subtracted from the incoming current leaving only the signal current on the charge well The signal current accumulates on the charge well for the integration period at which time the voltage is sampled the charge on the capacitor is removed and the accumulation cycle starts again The value from all 256 sample and hold circuits are multiplexed onto a single line and sent out Detailed Description Each detector element has a bias voltage Vbias applied to it The nature of photoconductive detectors is that they change resistance with incident photons
20. COMPONENTS S A S Phone 33 1 3959 5225 Fax 33 1 3959 5350 info lasercomponents fr ACTIONS WRITE DATA TO CSV To write a series of data samples at defined intervals to a file using the comma separated values csv format Maximum samples 65 000 click the Write Data button and enter the information as requested zig x Board Number 256 Data Acquisition ay Communications Infrared Array E v4 2 Cooler Cooler Cooler Control Power 3500 Input number of samples to take and the delay between samples 3000 Samples 5 2500 Delay m5 10 2000 56t 50 E 1 1 1 1 1 i0 20 30 40 50 60 70 ior DER MEE Ru 000 01 1500 1000 e i5 193 2 3 Bad Pixels Software Settings pa pa clear ui t 500 Correction Quick T Calibrate Array Led ork ed YYTICING Settings to board memory Control Board Information Serial Number 14006 save Restore Check Sum 0706 Test Array 3 96 16 Cooler Error NVRAM Provides access to 400 bytes of data that can be stored in the non volatile memory on the USB interface board This is useful for storing system setup or calibration parameters This function is intended only to Siue idis 18 usage of the functions
21. With an applied bias voltage the electrical current out of a photoconductive detector will consist of two parts There will be an amount of current that exists when the element has no incident radiation dark current and a different amount of current when the element is exposed to the signal radiation A higher bias voltage will produce more overall current The signal current therefore can be determined by subtracting a known dark current from the total current coming from the detector element The difficulty with Lead Salt photoconductors PbS and PbSe is that the dark current is typically quite large compared to the signal current In addition the bulk resistance of the film changes significantly with changing temperature To stabilize the temperature the Cal Sensors array contains a thermoelectric cooler and a thermistor which is strategically located With feedback from the thermistor the cooler current can be modulated to accurately control the temperature of the detector array CSI 8085 8 08 Germany and other countries LASER COMPONENTS GmbH Phone 49 8142 2864 0 Fax 49 8142 2864 11 info lasercomponents com Great Britain LASER COMPONENTS Uk Ltd Phone 44 1245 491 499 Fax 44 1245 491 801 info lasercomponents co uk France LASER COMPONENTS S A S Phone 33 1 3959 5225 Fax 33 1 3959 5350 info lasercomponents fr With the variability due to temperature removed the task of the multiplexer is to determine the dark cur
22. countries LASER COMPONENTS GmbH Phone 49 8142 2864 0 Fax 49 8142 2864 11 info lasercomponents com CSI 8085 8 08 Great Britain LASER COMPONENTS UK Ltd Phone 44 1245 491 499 Fax 44 1245 491 801 info lasercomponents co uk France LASER COMPONENTS S A S Phone 33 1 3959 5225 Fax 33 1 3959 5350 info lasercomponents fr DoCalibrate Since calibration is one of the most important functions it is important to understand the process being performed by the interface board The DoCalibrate function looks at the current being generated by each pixel and attempts to calculate values for all DACs that will make all outputs equal to a target output voltage The actual target correction value is set by arraySetVal which is passed to DoCalibrate Intuitively the correction target should be as low as possible to provide the greatest range of output values Since the multiplexer cannot operate at the lower voltage rail there must be some minimum voltage that allows the full range of DAC correction values Typically an array can be calibrated with target values as low as 0 50V or 0 75V If pixels are marked as bad in the bPixMapArray sent to DoCalibrate their values are not used to calculate the DAC values If there is a bad pixel that is not marked typically the DAC Vh or DAC VI will be at the rail and the bad pixel will be either very high or low The correction for this is to mark the pixel bad and perform another calibration Changes
23. determined GetData Reads the digital data values for each pixel GetDeviceHandle Returns an address to the device used in all other function calls This should always be the first command sent MarkBadPixel Sends the bad pixel map to the board The board will not use values from bad pixels instead returning the average of the two adjacent pixels with GetData RestoreAll Restores settings from the non volatile RAM on the board previously saved with the StoreAll command SetDetBias Sets the bias level for the array Setintegration Sets the integration time for the array SetMuxSize Sets the size of the Mux This should always be set to 256 SetWellSize Sets the charge well to 1pF 4pF 7pF or 10pF StoreAll Stores array settings to non volatile RAM on the board TECoolerPower Turns on or off the cooler When on the temperature of the array will be held to the set point approximately 4 C Before any functions are called up there are several data structures that need to be established These structures are passed to various functions and should be initialized before us in a function Most functions are passed the Device Handle obtained from GetDeviceHandle and return a status variable which is 1 if the function completes successfully Please see the appendix of ADIC Library Documentation for a list of error codes Also note that there are specific functions that deal with multiple attached boards Please refer to the ADIC L
24. e pr imary c onsideration is s pectral s ensitivity s ince the sensor must cover the wavelengths of interest e E o system electronics are responsible for providing the v arious drive signals required the s ensor as well as handling th e m ultiplexed out put and c onverting ittoas tandard computer interface In it would be ad vantageous if the electronics provided control of aux f unctions s as tem perature s tabilization of the detec tor elec tronic functions should be provided with no additional system noise e Sof o With the availability of modern computing systems most s pectroscopic applications require software development for implementation T his may be high level PC programming or low level m icrocontroller c ode As traightforward s oftware de velopment p ath is e ssential i n modern spectroscopic systems fe Pa Optics Sensor Electronics Software Figure 1 Spectrometer Subsystems Germany and other countries LASER COMPONENTS GmbH Phone 49 8142 2864 0 Fax 49 8142 2864 11 info lasercomponents com Great Britain LASER COMPONENTS UK Ltd Phone 44 1245 491 499 Fax 44 1245 491 801 info lasercomponents co uk France LASER COMPONENTS S A S Phone 33 1 3959 5225 Fax 33 1 3959 5350 info lasercomponents fr Innovation of Solution ould be ad vantageous to orporat
25. ent photons on film the bias current must be disposed of in some manner This is often done a gain by modulati ng the signal radiation and then AC coupling the resultant signal which is effective but can lead to issues particularly in arrays where timing between elements is often critical Because the detector resistance can be held relatively constant by thermal stabilization of the detector a bias current subtractio n schem e can b e used The advantage of bias current subtractio n is that the source does not need to b e modulated and a true DC signal system can be implemented Subtracting a constant current from all of the array elements however does not provide adequate solution because the film fabrication process cannot guarantee highly uniform element to element resistances A scheme h as been developed where both global and per pixel subtraction of the bias current can be performed Figure 1 shows data from an array with particularly wide resistance variation both before dark current correction Uncalibrated and after correction using an 8 bit D A converter on each pixel The nea rly flat calibrated line shows the effectiveness of this process This dark current subtraction scheme allows DC o peration of the array eliminating any mechanical or electronic chopping Germany and other countries LASER COMPONENTS GmbH Phone 49 8142 2864 0 Fax 49 8142 2864 11 info lasercomponents com Great Britain LASER COMPONENTS UK Ltd Phone
26. in array parameters such as bias or well size will typically require a re calibration Changes in array operating temperature will also require a re calibration Conclusion With the Interface Electronics Board operating the Cal Sensors 256 Element Array becomes simply a process of issuing commands through a standard USB port This manual has provided the hardware and software details necessary to operate the array within this environment Please refer to the DLL library description in the ADIC Library Documentation for detailed library information CSI 8085 8 08 Germany and other countries LASER COMPONENTS GmbH Phone 49 8142 2864 0 Fax 49 8142 2864 11 info lasercomponents com Great Britain LASER COMPONENTS UK Ltd Phone 44 1245 491 499 Fax 44 1245 491 801 info lasercomponents co uk France LASER COMPONENTS S A S Phone 33 1 3959 5225 Fax 33 1 3959 5350 info lasercomponents fr Recent Developments in Photoconductive Infrared Arrays Purpose The infra red region from 1umto 5 is an area of interest for b oth spe ctroscopic an d thermo graphic applications Lead sulphi de PbS a nd lead sele nide PbSe are intrinsically photo conductive materials that cover thi s important spectral re gion and hav e a long hi story of development and m anufacturing They have several advantages over competing materials but because of their n ature they have several challenges that need to be address ed This paper will outline the a
27. reference from the displayed reading switch the Reference On e SOFTWARE GAIN CORRECTION You may correct the gain of the current input data by clicking the Gain Correction Ref button and then turning the switch to On This multiplies each pixel by an amount to make the display uniform under illumination Typically you would do this after establishing a Reference if you are using that function SOFIWARE AVERAGING You may display the average of a number of readings by entering that number in the Averages box CONTROL BOARD INFORMATION SERIAL NUMBER The control board serial number is displayed e CHECK SUM The firmware check sum is displayed This indicates the firmware version SETTINGS TO BOARD MEMORY SAVE RESTORE SETTINGS The current calibration settings may be saved to the non volatile RAM on the controller board by pressing Save The software does an automatic Restore when it is started manual restore may be performed by pressing Restore All DAC global skim well size bias and bad pixel settings that were previously saved will be restored CSI 8073 9 08 Germany and other countries LASER COMPONENTS GmbH Phone 49 8142 2864 0 Fax 49 8142 2864 11 info lasercomponents com Great Britain LASER COMPONENTS UK Ltd Phone 44 1245 491 499 Fax 44 1245 491 801 info lasercomponents co uk France LASER COMPONENTS S A S Phone 33 1 3959 5225 Fax 33 1 3959 5350 info lasercomponents fr
28. test conditions Press OK after the information is entered and you will be asked to cover the array Pressing OK will initiate the gathering of 100 data samples You will then be asked to uncover the array exposing it to the calibrated illumination that you specified and again 100 data samples will be gathered Once all the data is gathered the test data sheet will be displayed with both basic and calculated results You may enter a comment in the appropriate section and print the data sheet on the system default printer by pressing Print Close the window when testing is complete to return to the main window A test report example is shown on the following page CSI 8073 9 08 Germany and other countries LASER COMPONENTS GmbH Phone 49 8142 2864 0 Fax 49 8142 2864 11 info lasercomponents com Great Britain LASER COMPONENTS UK Ltd Phone 44 1245 491 499 Fax 44 1245 491 801 info lasercomponents co uk France LASER COMPONENTS S A S Phone 33 1 3959 5225 Fax 33 1 3959 5350 info lasercomponents fr 256 Array Detector Test Report Test Results Manufacturing Order Unit Number Minimum Maximum Average St anne 0820020 sepa Tr T2 28 n Iradance 1 3 Wicm 2 Integration 100m 5 Light Noise Vrms f 64 97m 1258 _ 943m 14 53m Bad Pixels Signal Noise f 14 98 Part Number 17102 Well Size 6 ight Nonuniformity V 589 59m Material Bia
29. 50 info lasercomponents fr Power connection Power to the Interface Electronics Board is supplied through a six pin connector Power supplied to this board also supplies power to the detector array and the thermoelectric cooler Connector Pin Out Pin 1 BLACK Wire Ground Return for 12V power 100mA Pin 2 RED Wire 12VDC 100mA System Power Pin 3 amp 4 BLUE Wire Ground Return for TEC Power approx 2A Pin 5 amp 6 YELLOW Wire 5VDC 2 Amps TEC Power In addition the Development System powers the system s fan from the twelve volts power supply This requires an additional 500 milliamps for a total of 600 milliamps on the twelve volt supply This voltage can be reduced to provide greater cooler control stability if the PWM value is below 1590 Note that the Ground Returns for both the 12V power and the TE power pins 1 3 and 4 must be connected together at the system common ground point otherwise damage may result to the controller board USB Power Connector Connector Pin 1 CSI 8073 9 08 Germany and other countries LASER COMPONENTS GmbH Phone 49 8142 2864 0 Fax 49 8142 2864 11 info lasercomponents com Great Britain LASER COMPONENTS UK Ltd Phone 44 1245 491 499 Fax 44 1245 491 801 info lasercomponents co uk France LASER COMPONENTS S A S Phone 33 1 3959 5225 Fax 33 1 3959 5350 info lasercomponents fr Section 4 Cal Sensors 296 Element Array Development System User s M
30. 56 p Output Buffer T Integration Clock CLOCK CONTROL Start Frame 24 Serial Data DARK CURRENT CORRECTION T Vv I Case M NES 28 Pin Package 28 Siz 18 Germany and other countries LASER COMPONENTS GmbH Phone 49 8142 2864 0 Fax 49 8142 2864 11 info lasercomponents com Great Britain LASER COMPONENTS Uk Ltd Phone 44 1245 491 499 Fax 44 1245 491 801 info lasercomponents co uk France LASER COMPONENTS S A S Phone 33 1 3959 5225 Fax 33 1 3959 5350 info lasercomponents fr G HSINH esl NOILVWaOHNI Aa V 13leldOeld NOILOJ ONd 31ONY IVIN3GHNOO cj C 5 N e 326 7 cxwo 957 182 uro xwusy Lixs wr 90000 XXXXX 91412345 ASIMASHLO 5859131 5105 38 1VO 11 25 LON ___5 g 8NOISIWN3HL 20 sviga l __ 96 0N SC Viva vc Ol Pyro axis tt 6 V QS3 20 SsvigNisd 8 Ie VISIWA 400 __ 006 9 6i S SA 8 ON _ 91 SI NO
31. ER COMPONENTS GmbH Phone 49 8142 2864 0 Fax 49 8142 2864 11 info lasercomponents com Great Britain LASER COMPONENTS Uk Ltd Phone 44 1245 491 499 Fax 44 1245 491 801 info lasercomponents co uk France LASER COMPONENTS S A S Phone 33 1 3959 5225 Fax 33 1 3959 5350 info lasercomponents fr Software Control Descriptions e DATA ACQUISITION Continuously acquire data by pressing the Data Acquisition button Press it again to turn off data acquisition e ARRAY COMMUNICATIONS Starts or stops communication with the array no array is currently available an error message is displayed The close window icon is only enabled when the array communications is Off PIXEL DATA GRAPH The data display can be manipulated zoom scale etc by using the control selectors at the bottom of the graph Right clicking on the graph elements also brings up a menu to control the graph settings The data range of the Y axes can be changed by double clicking on the axis data values and typing in new min and max limits The default Y axis data range is OV to 5V which corresponds to the array output limits MULTI BOARD INTERFACE This feature set located to the left of the DATA ACQUISITION button allows the user to connect multiple Array devices to the software by communicating through separate USB ports SOFTWARE SETTINGS e SOFTWARE REFERENCE You may set the current input data as a reference by clicking the Ref button To subtract the
32. Ltd Phone 44 1245 491 499 Fax 44 1245 491 801 info lasercomponents co uk France LASER COMPONENTS S A S Phone 33 1 3959 5225 Fax 33 1 3959 5350 info lasercomponents fr 256 ARRAY THERMISTOR MUX CHIP INTERCONNECT THERMOELECTRIC COOLER HEADER Figure 3 Design Concept Exploded Figure 4 Design Realization Internal Germany and other countries LASER COMPONENTS GmbH Phone 49 8142 2864 0 Fax 49 8142 2864 11 info lasercomponents com Great Britain LASER COMPONENTS UK Ltd Phone 44 1245 491 499 Fax 44 1245 491 801 info lasercomponents co uk France LASER COMPONENTS S A S Phone 33 1 3959 5225 Fax 33 1 3959 5350 info lasercomponents fr Figure 5 Design Realization Packaged Conclusion Lead salt hotoconductive films a re a mature te chnology tha t have sh own gen eral usefulness a 5 detectors in t he near and mid infra red regions both sp ectroscopic and th ermographic applications Advances in integrated circuit design photolithography ion milling hermetic sealing and thermoelectric cooling can be a pplied t o p roduce d etector a rray assemblies that take a dvantage ofthe b enefits of photoconductive arrays while compe nsating for th eir va rious characteristics Theseissues and their solutions have been presented in theory and practice showing an economically producible detector array package for easy implementation in both spectroscopic and thermogra
33. MONM3 ONNId 80 1740 Wad JLON ONMGNVH 993 3301833 804140 wad SNOISN3IIG ONY ANITLNO 1VOINVHO3W 404 Z 338 ava ____ SALON SNOISIA33 G 11928 0061 word X8C 27 ON OMQ 326 001 09073 91 41 8l 6 Oc 161262 vo STIS LE 80 1 009 006 ggg 90 vl l ZL tl OL 6 812 9 G v Gol GCC 080 Z 3ov4ans 082 010 191 Id AVelel V OVS SOL 0 2 pem QOS O00 I Jelf Leldd V 016 052 OOS OSE SNOISIA33 133H 33 0027 SALON 404 1 1435 33 CalSensors LASER COMPONENTS LIRA 206 Element Multiplexed Arrays for Thermography and Thermal Imaging Lead Selenide PbSe 1 5 um PbSe Multiplexed Array Features The low profile package features a detector with square pixels on 50 micron centers The internal electronics provide variable integration and dark current correction u Temperature stabilization is achieved using an internal thermoelectric cooler and thermistor This product is designed thermography and thermal imaging applications 1 to 5 micron wavelength region The internal multiplexer includes a serial readout up to 4 MHz and global plus 8 bit per pixel da
34. SERIAL CLK 6 CFG LOAD CLK 7 FRAME START 8 NBIAS RST 9 DAC Vh MUX OUT 11 DAC VI GLOBAL SKIM DET BIAS NO CONNECTION NO CONNECTION NO CONNECTION DAC LOAD CLK PIXEL CLK SERIAL DATA NC TEC THERMISTOR B CASE Germany and other countries LASER COMPONENTS GmbH Phone 49 8142 2864 0 Fax 49 8142 2864 11 info lasercomponents com Great Britain LASER COMPONENTS UK Ltd Phone 44 1245 491 499 Fax 44 1245 491 801 info lasercomponents co uk France LASER COMPONENTS S A S Phone 33 1 3959 5225 Fax 33 1 3959 5350 info lasercomponents fr System Timing Diagrams Control Register Timing Diagram 0 17 2 3 4 5 86 7 8 39 10 1 12 13 14 15 16 17 1 01111111 11111111 111111111111111 111111 e OO 1 1 1 1 1 1 1 1 LAP CLK TIME 4 IFR Beginning of Integration Detail 250ns min Ousmin INT CLK START START FRAME pris t o Cub o kso will nidiaet Thee FRAME rom that a full array of 2245 piratas is With the rmamibser ad total read Pixel i Pixel Pixel Pixel Pixel widening Analog 247 249 251 253 455 last pixel would be Pixel 0 Pixel Stream IFR End of bliss ration Detail PIXEL CLK 250 5 min INT CLK START FRAME is clocked in by the edge of 1
35. active application acquiring data with the cooler on 3500 3000 2500 2000 1 1 I I 1 1 1 1 1 It n 10 20 30 40 50 60 720 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 mar 1500 RI UC RC C LAddr 0 0 Raddr Pixel Data 193 014 1000 Bad Pixels Software Settings Actions Reference Gain Correction 500 Averages Calibrate Array 7 Write Data to csv Test Array Control Board Information Settings to board memory Hide Serial Number 0 ON Check Sum 0 CSI256 i 2 0 x Board Number ET 256 Data Acquisition y Infrared Arra Um v4 2 y a Cooler Cooler Power Cold 100 Cooler 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 LAddr 0 0 Raddr 255 Bad Pixels pa pa clear Actions Quick Calibrate Array Write Data to csv Software Settings Reference Gain Correction Settings to board memory Control Board Information IR Check Sum 0706 Test Array CSI 8073 9 08 Germany and other countries LAS
36. anual 4 Detector Array General Description The Cal Sensors PbS PbSe array has 256 elements in a linear configuration Each element is 40 microns wide and 450 microns high on 50 micron center to center spacing The 28 pin array package contains the 256 element linear array integrating multiplexers a thermoelectric cooler and a thermistor for temperature control Absolute Maximum Ratings 0 7V Input Voltage any VPINMAX Vss 0 7 V PbS 40 to 65 Operating Temperature 40 to 55 PbS 40 to 65 Storage Temperature T stg PbSe 40 to 55 CSI 8073 9 08 Germany and other countries LASER COMPONENTS GmbH Phone 49 8142 2864 0 Fax 49 8142 2864 11 info lasercomponents com Great Britain LASER COMPONENTS Uk Ltd Phone 44 1245 491 499 Fax 44 1245 491 801 info lasercomponents co uk France LASER COMPONENTS S A S Phone 33 1 3959 5225 Fax 33 1 3959 5350 info lasercomponents fr Functional Block Diagram Cal Sensors 256 Element Multiplexed Array Functional Diagram CSI 8073 9 08 Germany and other countries LASER COMPONENTS GmbH Phone 49 8142 2864 0 Fax 49 8142 2864 11 info lasercomponents com Great Britain LASER COMPONENTS UK Ltd Phone 44 1245 491 499 Fax 44 1245 491 801 info lasercomponents co uk France LASER COMPONENTS S A S Phone 33 1 3959 5225 Fax 33 1 3959 5350 info lasercomponents fr CalSensors COMPONENTS 256 Element Array Progra
37. are amplified as the integration time increases T he result is that the dynamic range of the array is reduced as the integration time increases In practice the integration time may be increased until t he s ystem reaches the m inimum equired d ynamic r ange Atth e en d of the integration tim e the vo Itages on the 256 c harge wells are captured on a s ample and hold and th e charge wells are reset start an other integration cycle The electronics allows for read after integrate or read during integrate operation The 256 signal voltages are time division multiplexed onto a single output pin which will contain a stream of analog voltage levels which are proportional to the number of incident photons on each pixel T he readout timing is controlled by a pixel clock which can operate up to 2MHz allowing for a 7 8mS frame rate e Vbias Infrared Instantaneous Well Voltage Offset Correction All multiplexed Signals to Integration output reset Sample Voltage And Hold Time gt Analog voltage level represents det ector Figure 4 sensor Operation Diagram Germany and other countries LASER COMPONENTS GmbH Phone 449 8142 2864 0 Fax 449 8142 2864 11 info lasercomponents com Great Britain LASER COMPONENTS UK Ltd Phone 44 1245 491 499 Fax 44 1245 491 801 info lasercomponents co uk France LASER COMPONENTS S A S Phone 33 1 3959 5225 Fax 33 1 3959 5350 info lasercomponents fr
38. asercomponents com Great Britain LASER COMPONENTS UK Ltd Phone 44 1245 491 499 Fax 44 1245 491 801 info lasercomponents co uk France LASER COMPONENTS S A S Phone 33 1 3959 5225 Fax 33 1 3959 5350 info lasercomponents fr CalSensors 256 Element PbS and PbSe Arrays COMPONENTS 256 Element PbS Multiplexed Array Performance Parameter 00000000 Operating Wavelength Range 1 to 3 Microns PbSe Operating Temperature 4 C TEC stabilized Number of Elements 256 detector elements Element Size width 40 microns pixel height 450 microns ement Size and pixel pitch 50 microns Peak Detectivity _____________ 0 PbS 1x10 4 C Response Uniformity pixel to pixel ________ 10 of array signal mean PbS Integration Range _______________ 1M to 200ms on board Pixel Clock MHZ Linearity 00 Pixel Operability P8 Detector Rise Input Power Requirement 0012 VDC main 5 1 5 cooler Detector Array Input Circuitry Charge Well Sample amp Hold MUX Out 4 13 01 D1 b 01 D1 Di MUX Out m 10 Detector 0256 a i Bias 0 DZ 185 Output Buffer 13 Integration Clock 23 Pixel Clock CLOCK CONTROL 7 Start Frame Serial Data 22 DAC Ld Clock gt Serial Clock 94 CFG LOAD CLK DARK CURRENT CORRECTION 2r 2 1 3 Vss 128 Gnd t17 18 28 Pin
39. ations Use the check boxes below to limit expand the default search which includes local paths and removable media The best driver Found will be installed Search removable media floppy CD ROM Include this location in the search C Program Files CSI256v4 Drivers Don t search will choose the driver to install Choose this option to select device driver fram a list Windows does not guarantee that the driver vou choose will the best match for your hardware 5 You may receive a notice that the driver has not passed Windows Logo testing Please click on Continue Anyway Click Finish to complete the hardware driver installation wizard There will now be an ADIC Linear MUX Array Controller entry under the Universal Serial Bus Controllers heading in the Windows Device Manager The software installing for this hardware ADIC Linear Controller A4 not passed Windows Logo testing to verify its compatibility with Windows P T ell me why this testing is important Continuing your installation of this software may impair destabilize the correct operation of pour system either immediately or in the future Microsoft strongly recommends that you stop this installation now and contact the hardware vendor for software that has passed Windows Logo testing Continue Anyway STOP Installation 6 Once the program has comple
40. ax 44 1245 491 801 info lasercomponents co uk France LASER COMPONENTS S A S Phone 33 1 3959 5225 Fax 33 1 3959 5350 info lasercomponents fr WINDOWING e A subset of the entire array be read out by adjusting the right and left white arrows on the pixel graph Board Number 256 Element I Data Acquisition Array Infrared Array E Tura EET 20101405 60 50 920 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 255 BAD PIXELS OGGLE CURRENT CLEAR ALL A bad pixel can be marked or unmarked by moving the data cursor yellow crosshair to the pixel and clicking on Toggle Current The bad pixel will appear in the Bad Pixel List All bad pixels can be cleared by clicking on Clear All To select the current pixel select the data cursor and drag it to the new position You may also type the pixel number into the data legend which shows the data value of the selected pixel There are also options to change the data cursor appearance e HIDE Toggles whether to hide or show the bad pixels When Hide is selected a bad pixel is given a value of the average of the two adjacent pixels CSI 8073 9 08 Germany and other countries LASER COMPONENTS GmbH Phone 49 8142 2864 0 Fax 49 8142 2864 11 info lasercomponents com Great Britain LASER COMPONENTS UK Ltd Phone 44 1245 491 499 Fax 44 1245 491 801 info lasercomponents co uk France LASER
41. ce arrays of high pixel functionality often 100 This is not q uite as easily achieved with other detector m anufacturing techniques and is an advantage for these detectors Array 256 elements Multiplexers ROIC Integration dark current removal multiplex to single output Thermistor gt Measure tem p on board Circuit Board Routes ignals to pins between multiplexers Thermoelectric Cooler Header Figure 3 Sensor Implementation Germany and other countries LASER COMPONENTS GmbH Phone 49 8142 2864 0 Fax 49 8142 2864 11 info lasercomponents com Great Britain LASER COMPONENTS UK Ltd Phone 44 1245 491 499 Fax 44 1245 491 801 info lasercomponents co uk France LASER COMPONENTS S A S Phone 33 1 3959 5225 Fax 33 1 3959 5350 info lasercomponents fr Figure 4 shows operation of the sensor The bias voltage on th e photoconductive detector generates current that varies de pending o n th e num ber of photons on t he detector surface T he charge from this current is collected in a capacitor called the Charge Well When the detector is not illuminated the current is called Dark Current T his dark current can be referenced and subtracted from all of the pixels a process generally referred to as First Order or Offset Correction Because the resistance of each element in th e array is identical a g lobal offset correction is typically not s atisfa
42. ctory in reducing th e dark current to levels that provide adequate dynamic range To further improve the offset correction each pixel is provided with a D A converter which when provided with a d igital correction value will individually a the of fset correction value of that pixel The number of bits available in the D A converter will determine the resolution of the c orrection a vailable T he im plemented s cheme pr ovides 8 b its of c orrection which is t ypically adequate for the pixel to pixel non uniformities encountered Once the dark current is subtracted from the pixels the remaining current represents the difference in current between the d ark state and the il luminated state which is the s ignal current Sinc e this detector array is intended f or s pectroscopic appl ications i ntegration is r equired f or app lications in volving lo w i ncident radiation T he signal current will collect on t he charge well for a s pecified amount of tim e im plementing signal integration In order to offer the maximum flexibility and dynamic range both the integration time and the well size are adjustable by sending the sensor digital values to the IC T he integration time is hardware limited to a m inimum of 10155 and a m aximum of 218m 5 In pr operation the m aximum integr ation time is limited b y the uniformity of the ar ray after correction Even with good uniformity and dark current correction the differences in pix el offsets
43. d all other factors remain constant a given calibration would never need to be repeated In practice because of changing temperature and other factors the calibration process will need to be repeated at some interval This needs to be performed more or less often depending on the stability or resolution required by a particular application The resulting signal current is accumulated on the charge well capacitor The size of this capacitor can be set to 1pF 4pF 7pF 10pF 11pF 14pF 17pF or 20pF Decreasing the charge well size effectively increases the gain of the system in that the resultant voltage on the charge well after a certain integration time will be greater with a smaller capacitor Since the total charge accumulated depends on bias voltage detector resistance dark current subtraction accuracy and integration time it is important to select a capacitor size that can accommodate the charge accumulation without filling up otherwise signal clipping will occur Once the integration time is completed the charge well is sampled and the resulting voltage held in a sample and hold circuit This sampled voltage is proportional to the signal photons on the detector element After the sampling is accomplished the charge well is reset and the charge accumulation repeats The resulting 256 voltage levels are multiplexed at a fixed clock rate onto the single output line Figure 3 shows the array pin assignments with the associated functional b
44. d etector material determines many of the f eatures of the e lectronics interface In a general s ense th e electronics needs to in terface with the s ensor perform as much correction as pos sible and present the output through a standard computer interface n addition the electronics should perform any control functions such as temperature control If the detector array is to contain a significant number of pixels the multiplexing electronics should be contained within the detector package to improve performance and m inimize pac kage pin count Si nce the g oal is an int egrated s pectroscopic s ystem the har dware architecture is influenced by the desire for simple software interaction The software interface should not be language specific to afford the broadest usability T his is most easily implemented as a library of functions to control and interface with the detector array This also implies that the interface hardware is most easily implemented in a microcontroller based architecture Technical Realization Cal Sensors has pr oduced PbS a nd PbSe p hotoconductors f or over 20 years and ecently developed arrays that ar e specifically designed to c over the n ear and m id infrared spectrum at r easonable cost with high s ensitivity Eac h s ensor consist of 256 phot oconductive e lements hous ed in an in dustry standard 28 pin p ackage which also contains a Pe cooler 4 ther mistor for thermal stabilization and in
45. d to provide Min Max Average and Standard Deviation test criteria SaveLoadPFSettings y i CSI 8073 9 08 Germany and other countries LASER COMPONENTS GmbH Phone 49 8142 2864 0 Fax 49 8142 2864 11 info lasercomponents com Great Britain LASER COMPONENTS Uk Ltd Phone 44 1245 491 499 Fax 44 1245 491 801 info lasercomponents co uk France LASER COMPONENTS S A S Phone 33 1 3959 5225 Fax 33 1 3959 5350 info lasercomponents fr Section 3 Cal Sensors 206 Element Array Development System User s Manual 3 Interface Electronics Board General Description The interface electronics board contains a microcontroller that supplies all timing and cooler control for the system along with USB interface circuitry and a current switch for powering the cooler System control is provided by sending commands over the USB interface The cooler is controlled by Pulse Width Modulating the supplied cooler current based on feedback from the thermistor The set temperature is determined by a resistor located the Interface Electronics Board This set temperature is approximately 4 C CSI 8073 9 08 Germany and other countries LASER COMPONENTS GmbH Phone 49 8142 2864 0 Fax 49 8142 2864 11 info lasercomponents com Great Britain LASER COMPONENTS Uk Ltd Phone 44 1245 491 499 Fax 44 1245 491 801 info lasercomponents co uk France LASER COMPONENTS S A S Phone 33 1 3959 5225 Fax 33 1 3959 53
46. e as m any of thes e s ubsystems as pos ntoas ingle spectroscopic s olution while m aintaining the f lexibility nec essary t o be ap plicable toa wider ange of applications Since the optical performance and layout is very specific to the particular application the Optics subsystem w ill n ot be included in t he s olution T he remaining s ubsystems Sensor E lectronics and Software can all be tightly integrated and be relatively independent of the optical design f course the sensor material selection will be determinative of the spectral range covered oince th e g oal is to address inf rared s pectroscopy and s pecifically n ear to mid inf rared on ly d etector materials with esponse in the region will be c onsidered f th ese detectors there a number which typically operate at very cold temperatures These include InSb InAs and HgCdTe Since the design goal parameters include small and low cost these detector materials will not be considered due to the size and cost of their cooling s ystems Thermal detectors us ing P yroelectric or Bolometric m aterials could b e considered b ecause of their broad wavelength response ho wever th ey have low sensitivity and slow response speed compared to ph oton detectors so they would be inappropriate for a gener al purpose spectroscopic s ystem T he detector materials that remain for consideration are InGaAs photodiodes both standard nd ex tended a nd lea d
47. een developed to attempt to comp ensate for the chan ge in dete ctor resistance and responsivity that occur as the temperature of the film changes Som e of the se schemes in clude elements such as per detector thermal compensation elements that are compatible with large pixel count arrays The most simplistic approach is to hold the detector temperature constant as the ambient temperature changes Fortunately advances in Peltier cooling technology and cooler control design make it relatively easy to include a thermoelectric cooler temperature sensing device and control electronics 2 3 into any system solution The solution chosen for this development was a thermoelectric cooler with a surface area larg e e nough to e ncompass both the dete ctor array and the i nterfacing electronics chip Holding both the detectors and the electronics in an isothermal condition insures maximum stability in the device Lo cating the se nsing eleme nt as clo seto the center of the isothermal surface as po ssible improves the feedback to the control circuit Dark Current As previously discussed in the typical bias arrangement there is a bias or dark current generated by the bias voltage being applied across the bulk dark resistance of the photoconductor Because the change in resistance due to photo n generated carriers is small compared to the bulk resi stance of the film the signal current change is commensurately small In order to dete ct the incid
48. ensitivity to 1 7um and therefore can not be considered for a general purpose solution even in the near infrared Extended InGaAs photodiodes have reasonable sensitivity but still only extend to 2 6um T he remaining alternatives PbS an d Pb Se photo conductors have characteristics that ma ke them excellent candidates PbS has detectivity values that are at least as good as Extended InGaAs with sensitivity to PbS eis app roximately an order of magnitude less sensitive than PbS but ha s sensitivity to History of lead salt photoconductors Lead salt photoconductors have a long history of development The photoconductive properties of le ad sulfide PbS were di scovered in 1933 by Kutzsche r at the University of Be rlin although his work w as performed in great secrecy and not publicly known until after 1945 1 Lead sulfide was also produced by Cashman Northweste rn University a nd Gud den University of Prague an d impleme nted for vario us military appli cations at th at time and indicated g ood sen sitivity to Robert Cashman was also working with other lead salt compounds and sh owed that lead sel enide PbSe also had p romise as a photoconductor to whi ch wa s p articularly important be cause of the uim atmosp transmission window Commercial production of PbS began around 1943 in Germany 1944 in the United States Northwestern University and 1945 in England Admiralty Research Laboratory
49. fr Section 3 Cal Sensors 206 Element Array Programming Manual Interface Board Principles of Operation General Description The interface electronics board contains a microcontroller that supplies all timing and cooler control for the system along with USB interface circuitry and a current switch for powering the cooler System control is provided by sending commands over the USB interface The cooler is controlled by Pulse Width Modulating the supplied cooler current based on feedback from the thermistor The set temperature is determined by a resistor located on the Interface Electronics Board This set temperature is approximately 4 C CSI 8085 8 08 Germany and other countries LASER COMPONENTS GmbH Phone 49 8142 2864 0 Fax 49 8142 2864 11 info lasercomponents com Great Britain LASER COMPONENTS UK Ltd Phone 44 1245 491 499 Fax 44 1245 491 801 info lasercomponents co uk France LASER COMPONENTS S A S Phone 33 1 3959 5225 Fax 33 1 3959 5350 info lasercomponents fr Features Standard USB interface using Windows dynamic linked library for interface functions e Small size 1 4 x 2 1 e 10 bit linear precision array voltage settings providing all of the required array voltages from a single 12V input 16bit output signal digitization at 500K samples second Non volatile storage of array settings and user data e High efficiency thermoelectric control to fixed temperature
50. ibrary Documentation under the section Working With Multiple Controller Boards CSI 8085 8 08 Germany and other countries LASER COMPONENTS GmbH Phone 49 8142 2864 0 Fax 49 8142 2864 11 info lasercomponents com Great Britain LASER COMPONENTS Uk Ltd Phone 44 1245 491 499 Fax 44 1245 491 801 info lasercomponents co uk France LASER COMPONENTS S A S Phone 33 1 3959 5225 Fax 33 1 3959 5350 info lasercomponents fr Data Structures The 256 element array of DAC correction coefficients bPixMapArray or The 256 element array of bad pixels Should be 1 at bad pixel bpMap locations otherwise all O The 256 element array of pixel values returned from GetData BaseSettings A 16 element array containing array settings BaseSettings 0 Integration Time BaseSettings 1 NOT USED value will ALWAYS be 0 BaseSettings 2 Global Skim value BaseSettings 3 NOT USED value will ALWAYS be 0 BaseSettings 4 DACVh value BaseSettings 5 NOT USED value will ALWAYS be 0 BaseSettings 6 DACVI value BaseSettings 7 NOT USED value will ALWAYS be 0 BaseSettings 8 NOT USED value will ALWAYS be 0 BaseSettings 9 Detector Bias BaseSettings 10 Mux Size BaseSettings 11 5 Direction Flag BaseSettings 12 Number of Bad Pixels BaseSettings 13 Integration Well Size BaseSettings 14 Left wndow address BaseSettings 15 Right window address Sequence of Events Pan d uu WW WW The standard sequence
51. ical photoconductive arrays have been developed and cover this entire spectrum To aid in the e lectronics har dware des ign a no vel inter face board is available th at incorporates am icrocontroller which c ontrols a Il interface to the internal multiplexers an d per forms temperature stabilization control and signal digitization T his board accepts commands and tr ansfers data through a standard USB interface The software interface is implemented through a library of functions and is demonstrated in a Lab View application The sensor system is currently available in production quantities from Cal Sensors Inc for shipment worldwide Germany and other countries LASER COMPONENTS GmbH Phone 49 8142 2864 0 Fax 49 8142 2864 11 info lasercomponents com Great Britain LASER COMPONENTS UK Ltd Phone 44 1245 491 499 Fax 44 1245 491 801 info lasercomponents co uk France LASER COMPONENTS S A S Phone 33 1 3959 5225 Fax 33 1 3959 5350 info lasercomponents fr CalSensors Important Note During further technical development an important change has been made A new 256 channel multiplier did replace in 2008 the two 128 channel multipliers The advantage is a more homogeneous signal and a simplification of the read out All following information in this product file is related to the new version with one 256 channel multiplexer Germany and other countries LASER COMPONENTS GmbH Phone 49 8142 2864 0 Fax 49 8142 2864 11 info l
52. icrosoft Windows de velopment langua ge as well as through National Instrument s LabView A LabView application has been developed and is supplied with the system to easily take data from the array Setup is as simple as installing the USB drivers and running the application software csi256 vi m Data Acquisition Array 256 Element 9 Communications Infrared Array gt Cooler Cooler Power 0 0 1 1 100 0 20 40 60 80 100 120 140 160 180 200 220 240 255 Pixel Data 178 00 1 10 sima Pixel iem E E Bad Pixels Software Settings Actions C Cim Gain Correction pests TETTI zem gom Calibrate 1 Write Data Cocker 202 Hardware Settings Control Board Information Settings to board memory Averages 1 Array Order 15 Serial Number 1008 Check Sum 125462 Figure 6 Application Software Results The goal of this project was to develop a core system that would facilitate the rapid development of infrared spectrometer systems to address the growing market and to eliminate the need for experts in s pectroscopy to become experts in detectors and their associated interface hardware With the addition of the appropriate optics and some software customization an infrared spectrometer can easily be developed in the to infrared range T wo geometrically ident
53. ifficult An coupled circuit i s n used and the radiation so urce is m odulated by mechanical chopper or electronic pulsed source means B esides providing the ability to ea sily distinguish the photocurrent this method has the added advantage of minimizing the dete ctor noise including 1 f noise inherant in t hese d etector mate rials by use of a band pass filter or lock in amplifie r centered at th e modulation frequency The disadvantage of th e modulated source method is the size and complexity of modulating the source and the fact that slow or steady state radiation changes cannot be detected Because of the nature of photoconductive materials there are several issues that need to be addressed to insure a successful product This is particularly important in applications that require high sensitivity such as reflective spectroscopy or precision thermography Thermal Coefficient of Resistance Photoconductive detectors havea bulk re sistance which i s temperature ependent For lead salt photoconductive films thi s temperature dependency is typically on the order of 3 C The problem is that if the bul k resistance is changing due to tempe rature variations it can b e indistinguishable from th e photoconductive signal M odulation of the signal radiation can help address this issue but t his requires extra hardware and is not an option where modulation is not compatible or desired in the system solution Several schemes have b
54. lock diagram Many of the pins are associated with clocking and control functions and require digital logic to implement For systems that already contain digital logic or microcontroller functions this may be practical to provide Many systems however are computer based and need to interface through standard ports This functionality is provided by the Interface Electronics Board described in the next section CSI 8085 8 08 Germany and other countries LASER COMPONENTS GmbH Phone 49 8142 2864 0 Fax 49 8142 2864 11 info lasercomponents com Great Britain LASER COMPONENTS UK Ltd Phone 44 1245 491 499 Fax 44 1245 491 801 info lasercomponents co uk France LASER COMPONENTS S A S Phone 33 1 3959 5225 Fax 33 1 3959 5350 info lasercomponents fr Cal Sensors 256 Element Multiplexed Array Functional Diagram Charge Well Detector Array Input Circuitry Sample amp Hold MUX Out Detector 10 i Bias Output Buffer DARK CURRENT CORRECTION 2 de Vss at 28 17 18 28 Pin Package e Figure 3 Array Pin Functions CSI 8085 8 08 Germany and other countries LASER COMPONENTS GmbH Phone 449 8142 2864 0 Fax 49 8142 2864 11 info lasercomponents com Great Britain LASER COMPONENTS UK Ltd Phone 44 1245 491 499 Fax 44 1245 491 801 info lasercomponents co uk France LASER COMPONENTS S A S Phone 33 1 3959 5225 Fax 33 1 3959 5350 info lasercomponents
55. mming Manual CSI 8085 8 08 Germany and other countries LASER COMPONENTS GmbH Phone 49 8142 2864 0 Fax 49 8142 2864 11 info lasercomponents com Great Britain LASER COMPONENTS Uk Ltd Phone 44 1245 491 499 Fax 44 1245 491 801 info lasercomponents co uk France LASER COMPONENTS S A S Phone 33 1 3959 5225 Fax 33 1 3959 5350 info lasercomponents fr 1 Cal Sensors 296 Element Array Programming Manual 1 Introduction The purpose of this manual is to provide our customers with the basic operating principles of the Cal Sensors 256 Element Multiplexed Array as interfaced through the Electronics Interface Board With this information and the ADIC Library Documentation the user will be able to write code to operate the array in a variety of programming languages The ADIC Library Documentation provides detailed information on each function as well as information regarding specific language interfacing error code definitions and documentation on working with multiple arrays on a single computer The 256 Element Array package can be interfaced to directly without the interface board but requires a significant amount of digital logic and various voltages The interface board simplifies the operation of the array by providing all necessary voltages timing and thermoelectric cooler control functions The array interface is then accomplished by sending commands over a USB interface using a standard Windows dynamic linked
56. n or explore the contents of the Cal Sensors Array CDROM media 2 Run Setup exe program and follow the instructions File Edt Favorites Tools a 13 pe Search Folders 4 Hay Address gt Name Date Modified Location Files Currently on CD File Folder 8 13 2008 10 38 AM Files Currently on the CD license File Folder 8 13 2008 10 38 AM Files Currently on the supportfiles File Folder 8 13 2008 10 38 AM Files Currently on the CD 15 nidist id 1KB IDFile 8 13 2008 9 57 AM Files Currently on the CD setup exe 3 888 KB Application 6 18 2008 5 19 PM Files Currently on the CD setup ini 8KB Configuration Settings 8 13 2008 9 57 4M Files Currently on the CD 3 completion of the installation you must restart your computer Installation Complete The installer has finished updating your system 51256 42 Ry must restart your computer to complete this operation If you need to install hardware now shut down the computer If you choose to restart later restart your computer before running any of this software Shut Down Restart Later CSI 8073 9 08 Germany and other countries LASER COMPONENTS GmbH Phone 49 8142 2864 0 Fax 49 8142 2864 11 info lasercomponents com Great Britain LASER COMPONENTS UK Ltd Phone 44 1245 491 499 Fax 44 1245 491 801 info lasercomponents co uk France LASER COMPONENTS S A S
57. nsor IC Conversely analog signals from the s ensor ar e di gitized for c ommunication t hrough the US B i nterface to the hos tc omputer he microcontroller responds t o a dig ital command structure to im plement all s ensor IC f unctions as well as thermoelectric cooler control and several auxiliary functions Germany and other countries LASER COMPONENTS GmbH Phone 49 8142 2864 0 Fax 49 8142 2864 11 info lasercomponents com Great Britain LASER COMPONENTS UK Ltd Phone 44 1245 491 499 Fax 44 1245 491 801 info lasercomponents co uk France LASER COMPONENTS S A S Phone 33 1 3959 5225 Fax 33 1 3959 5350 info lasercomponents fr Software The s pectrometer de veloper r equires a s ensor s ystem that wil s upply i nformation abo ut th e i ncident wavelength dis persed photons on eac h pixel A hi gh level of hardware abstraction releases the d eveloper from havi ng to understand the hoton to data c onversion pr ocess anda llows c oncentration o n the development of s ystem optics and the software necessary to im plement the target system T othis end a software i nterface li brary was dev eloped to im plement al I functions r equired to c ontrol and o perate th e infrared s ensor t hrough t he in terface el ectronics bal ance between ow evel c ontrol and h igh level abstraction was the goal and was achieved through customer feedback through the development process The library can be accessed thr ough a ny p opular M
58. of events when interacting with the array is as follows 1 9 91 m 9 10 11 Call GetDeviceHandle to get the device handle An error will be returned if there are no devices attached they are not powered up or there is some other communication problem Note The USB drivers must be installed on any system using the array before any communication is possible Initialize and place all zeros in the bad pixel array Set the mux size to 256 using SetMuxSize Set a well size using SetWellSize 10pF is a good start Set the integration time using Setlntegration 500uS is a good start Set the detector bias using SetDetBias 7V is a good start Call TECoolerPower with a teStatus of 1 if required to turn the cooler on a Note Ensure that the array has sufficient heatsinking prior to issuing this command b Wait until the temperature has stabilized before calibrating Call DoCalibrate making sure the parameters passed have all been initialized a Remember to cover the array during calibration b A value of 1 0 is a good starting point for arraySetVal Call GetData as necessary making sure the parameters passed have all been initialized If the cooler has been turned on TECoolerPower with a teStatus of 0 to turn the cooler off At the end of communications call CloseDevice If the array status was previously stored with the StoreAll command steps 3 6 may be skipped by calling RestoreAll Germany and other
59. onents com Great Britain LASER COMPONENTS Uk Ltd Phone 44 1245 491 499 Fax 44 1245 491 801 info lasercomponents co uk France LASER COMPONENTS S A S Phone 33 1 3959 5225 Fax 33 1 3959 5350 info lasercomponents fr The implementation consists of the following elements that address the stated detector issues Achemically dep osited d etector a rray whi ch uses a combin ation of ph otolithography a nd ion milling to produce the required geometries in both rectangular and square pixel configurations Adedicated second generation silicon chip to handle the ele ctronic inte to the array and provide other features and enhancements e Anindu stry stand ard package capable of hou sing the criti cal comp onents in a herm etic environment with a UV Visible filtering window e Athermoele co oler with physi cal therma an d electri cal characteristics matched t o the package and thermal load Athermal se nsing el ement ca refully positioned to provide the optimal fe edback toa control circuit Figure 2 and Figure 3 show the design concept which considers all of the aspects of the design 3D modelling was im portant to capture the phy sical electrical and thermal aspects of the design The manufacturability of the design p roducea g ood cost performance ratio was al soa primary consideration and is shown implemented design is shown in Figure 4 The detector pixels can be either rectangular for spectro
60. or DC operation The resistance of a lead salt photoconductor varies by approximately 3 p er C The sensor provides thermal control and m onitoring elements so the microcontroller is able to monitor the detector temperature by placing the thermistor within a bridge network with a fixed resistor to set the control resistance The microcontroller then issues a pulse width m odulated signal to a FET which controls the current of the ther moelectric cooler contained in t he sensor pac kage T he efficiency ofthis s ystem does notr equire an y heatsinking of the F ETandthe microcontroller synchronizes the timing of the high current drive pulses with the pixel clock to eliminate any noise that would result if the system were run asynchronously The sensor provides a multiplexed analog output stream as previously described The interface electronics accepts this analog stream by generating a pixel clock which is synchronized with a 14 bit A D converter and provides a d igital representation of the p hoton input o n each pix el T he conversion rate is 100k samples second which s ets the m aximum digital s ample r ate of the s ystem and is s ufficient f or m ost spectroscopic systems The inter face elec tronics is command based and a USB interface ar chitecture w as s elected to f acilitate straightforward system hardware software interface Digital signals enter through the USB interface and are converted to analog if necessary before communication with the se
61. phic applications Bibliography 1 Rogalski Antoni nfrared Photon Detectors Bellingham SPIE 1995 2 Woodward W Stephen Thermoelectric cooler unipolar drive achieves stable temperatures EDN 3 December 2007 S 98 3 Study of a Silicon Photodetector Thermal Stabilization using a Peltier Cell E Foschi C Guandalini G Levi L Quadrani C Sbarra M Zuffa Grenoble Proceedings of the COMSOL Users Conference 2007 4 MITTAL et al lon beam milling of n type mercury cadmium telluride for photoconductive devices SPIE Proceedings 16 September 1997 S 799 802 www lasercomponents com 07 09 V3 HW cal 256 pbs pbse arrays pdf Germany and other countries LASER COMPONENTS GmbH Phone 49 8142 2864 0 Fax 49 8142 2864 11 info lasercomponents com Great Britain LASER COMPONENTS UK Ltd Phone 44 1245 491 499 Fax 44 1245 491 801 info lasercomponents co uk France LASER COMPONENTS S A S Phone 33 1 3959 5225 Fax 33 1 3959 5350 info lasercomponents fr
62. pplic ation of s everal es tablished technologies that have be en appli ed to make PbS and PbSe arrays compatible with mod ern infrare d array applications An implementation will be shown that takes advantage of these techniques to produce a second generation array Problem Discussion Selection of Detector Material Comparison of detector materials A variety of detector materials can be considered for the small low powered low cost systems required today Of these d etectors there are a numb er which typically operate at very cold te mperatures to reduce thermally generated free carriers and achieve adequate performance These incl ude InSb InAs and HgCdTe Thesed etector materials cannot be con sideredu nless system performance requirements warrant the increased size cost and complexity Therm al detectors using pyroelectric or bolometric materials could be con sidered be cause of their b road wavelength response however they have lo w sensitivity and slo w response speed compared to photo n det ectors so th ey woul db e inappropriate for a ge neral purpose spectroscopic or thermometric system T he detector materials that remain fo consideration are InG aAs hotodiodes both standard and extende d and ead sa photoconductors PbS and PbSe All of these detectors have reasonable cooling requirements and good response times Stan dard InGaAs photodiodes have excellent sensitivity and speed but are limited in upper wavelength s
63. rent for each pixel and eliminate it so the signal current can be collected This is performed through a calibration process where the array element is covered removing all signal photons and the output current is measured This dark current can then be skimmed from the total current revealing the signal current In this system there actually two methods to remove the dark current The first is Global Skim where a fixed amount is skimmed from all 256 channels The second is an individual correction for each pixel typically required to accommodate the resistance variability of the photoconductive elements This individual correction is always used whereas Global Skim is often not used Both global and individual dark current corrections are included as Offset Correction in Figure 2 The individual pixel correction is implemented through a series of 256 digital to analog converters DACs All of the DACs operate between a high and low voltage DAC Vh and DAC VI Each 8 bit DAC divides this voltage range into 256 steps and applies the appropriate correction to each pixel depending on the individual dark currents The process of determining the DAC correction values for each pixel is referred to as Calibration The correction values are dependent on other settings integration time bias voltage etc so these values must be set and all signal radiation blocked prior to performing a calibration In theory if the temperature of the array an
64. rk current correction oignal integration is variable with adjustable well size and can be generated before during readout The array package is supplied with compact USB controller board optional for easy computer interface Can be supplied as a development system Germany and other countries LASER COMPONENTS GmbH Phone 49 8142 2864 0 Fax 49 8142 2864 11 info lasercomponents com Great Britain LASER COMPONENTS UK Ltd Phone 44 1245 491 499 Fax 44 1245 491 801 info lasercomponents co uk France LASER COMPONENTS S A S Phone 33 1 3959 5225 Fax 33 1 3959 5350 info lasercomponents fr 256 Element PbSe Multiplexed Array Performance Parameter Operating Wavelength Range Number of Elements Element Size Peak Detectivity Resistance Uniformity pixel to pixel Integration Range Pixel Clock Linearity Pixel Operability Detector Rise Time Input Power Requirement 540 APERTURE v ARRAY PLANE MOUNTING SURFACE R080 100 650 1300 161012 A 8 018 002 PINS Typical Performance 1 to 5 Microns 256 detector elements Pixel size 40 microns square and pitch 50 microns D 1 0 1079 Jones 15 of array signal mean 01mS to 200mS on board 2MHz max for 4 MHz data output 90 98 minimum lt 10 5 7 8VDC cooler 1 7 max PIN FUNCTION 1 DETECTOR BIAS 2T HERMISTOR A 3T 4 NC 5
65. s 8 00 v 25 07 Dark Signal V i ius Ambient Temp 23 C Global Skim 0 00 v Dark Noise Vrms Cooler PWM o T Temp 3 67 C 1 98 DarkNonuniformiy V 127 00m 00 7 25 Firmware Board Serial 4006 0706 DAC Vl Checksum DAC Nonuniformity V 194 56 154 81m Comment Data 5 0 o o 1 111 1 14 8 o o o Bl v 2 0 B 0 1 ee et ees gu 11 Il 0 5 LI jer per eo Fd JR D 10 2 40 50 60 7 E 100 uo 120 130 140 150 160 170 180 190 200 210 220 290 240 25 Pixel O 1 68 D EE HO d oo ooo rus UENIRE i pe Wl 1 67 CSI 8073 9 08 Germany and other countries LASER COMPONENTS GmbH Phone 49 8142 2864 0 Fax 49 8142 2864 11 info lasercomponents com Great Britain LASER COMPONENTS UK Ltd Phone 44 1245 491 499 Fax 44 1245 491 801 info lasercomponents co uk France LASER COMPONENTS S A S Phone 33 1 3959 5225 Fax 33 1 3959 5350 info lasercomponents fr e EDIT PASS FAIL This feature gives the user the ability to change and save custom Pass Fail criteria within the test function Each of the test parameters can be adjuste
66. s alt ph otoconductors PbS and P bSe A Il of thes e detec tors have reasonable cooling requirements and good esponse times Standard InGaAs photodiodes have excellent sensitivity a nd s peed but are limited in up per wavelength s ensitivity to 1 7 and th erefore can not be considered for a ge purpose solution even in near infrared Extended InGaAs photodiodes have reasonable s ensitivity b ut s till on ly ex tend to 2 Ther emaining alt ernatives Pb S an d Pb Se photoconductors have characteristics that m ake them excellent candidates PbS has detectivity values that are atleas t as go od as Extended InG aAs with s ensitivity to PbSeis oximately a n or der of magnitude less s ensitive than PbS b uth as s ensitivity to Sinc e both m aterials ar e s imilar photoconductors th ey could be used interchangeably within th e s ystem to pr ovide sensitivity through the broad range of to 5um The primary challenge in implementing a PbS PbSe spectroscopic system is that because thes e detectors operate in the ph otoconductive m ode the y have large dark currents Often these d ark c urrents ar e d ealt with b y m odulating t he i ncident r adiation and then f iltering out th e DC component This scheme works well but adds the complexity of source modulation A better solution would be to develop electronics sophisticated enough to deal with the dark current electronically The selection of the
67. scopic applications or square for thermo graphic applications The e ntire design including the interface IC can accommodate either configuration thereby providing a universal solution A key component is a se cond generation readout interface chip ROIC which has been developed by ADIC Inc Longwood FL USA This chip provides the following features Both global and 8 bit per pixel dark current subtraction 4MHz data readout speed Signal integration with selectable charge well size Input circuitry specifically designed to interface with PbS and PbSe photoconductors Advanced functionality including Data windowing Bidire ctional readout o Read while or after integration o Single supply operation Although a seemingly simple component the lid assembly provides hermetic sealing UV Visible blocking for both the silicon chip and detector array with good transmission over the wavelengths of interest and an optical aperture so careful design and material selection is critical Figure 5 shows the fully packaged array inclu ding an coated silicon window T he geo metry of the wi ndow is such th at the weldin g fixture provid es the alig nment necessary to insu that background radiatio n is reje cted while not vignetting the array elements Figure 2 Design Concept Germany and other countries LASER COMPONENTS GmbH Phone 49 8142 2864 0 Fax 49 8142 2864 11 info lasercomponents com Great Britain LASER COMPONENTS UK
68. ted at extreme ambient temperatures Ensure that the thermoelectric cooler does not overheat and the detector itself does not exceed min max temperature ratings noted on page sixteen of this manual CSI 8073 9 08 Germany and other countries LASER COMPONENTS GmbH Phone 49 8142 2864 0 Fax 49 8142 2864 11 info lasercomponents com Great Britain LASER COMPONENTS UK Ltd Phone 44 1245 491 499 Fax 44 1245 491 801 info lasercomponents co uk France LASER COMPONENTS S A S Phone 33 1 3959 5225 Fax 33 1 3959 5350 info lasercomponents fr Minimum System Requirements m Windows Operating System The software should work on Windows 98 or greater although it has not been tested on all configurations m Pentium processor or equivalent m 32MB of memory m 5MBofhard drive space m CD ROM for installation only m 256 color at 1024 x 768 minimum resolution m One available USB port CSI 8073 9 08 Germany and other countries LASER COMPONENTS GmbH Phone 49 8142 2864 0 Fax 49 8142 2864 11 info lasercomponents com Great Britain LASER COMPONENTS UK Ltd Phone 44 1245 491 499 Fax 44 1245 491 801 info lasercomponents co uk France LASER COMPONENTS S A S Phone 33 1 3959 5225 Fax 33 1 3959 5350 info lasercomponents fr Section 2 Cal Sensors 206 Element Array Development System User s Manual Installation To install the CSI256 CDROM application software follow these steps 1 Ope
69. ted installing the driver click FINISH to proceed to operation of the software Found Mew Hardware Wizard Completing the Found New Hardware Wizard The wizard has finished installing the software ADIC Linear Aray Controller 4 Click Finish to close the wizard CSI 8073 9 08 Germany and other countries LASER COMPONENTS GmbH Phone 49 8142 2864 0 Fax 49 8142 2864 11 info lasercomponents com Great Britain LASER COMPONENTS Uk Ltd Phone 44 1245 491 499 Fax 44 1245 491 801 info lasercomponents co uk France LASER COMPONENTS S A S Phone 33 1 3959 5225 Fax 33 1 3959 5350 info lasercomponents fr Operation The CSI256 application is simple to operate since all controls operate like real world objects The application is written using National Instruments LabView and utilizes all of the primary functions in the control DLL When the application starts all of the controls are disabled except for the Array Communications button Make sure the array is powered and plugged into the USB port on your computer then press the Start button 51256 1 EIE 256 Element 2 Data Acquisition Infrared Arra ot Communications v4 2 y 0 Cooler Cooler Cooler Control Power 4095 Cold After communications are established with the controller board all of the application controls become enabled and the Windows Close button becomes disabled The figure below shows the
70. ternal integrating multiplexers Interface electronics and software are also provided to easily transfer data via USB to a computer Germany and other countries LASER COMPONENTS GmbH Phone 49 8142 2864 0 Fax 49 8142 2864 11 info lasercomponents com Great Britain LASER COMPONENTS UK Ltd Phone 44 1245 491 499 Fax 44 1245 491 801 info lasercomponents co uk France LASER COMPONENTS S A S Phone 33 1 3959 5225 Fax 33 1 3959 5350 info lasercomponents fr Optical Input Electronics Software Sensor Figure 2 oystem Implementation Theory of Operation Sensor Detector and Multiplexing Electronics The array pixels are designed to easily interface with standard dispersive optics Two geometrically identical photoconductive arrays were developed so the entire to 5um region can be covered by selecting either PbS to or PbSe 1um to The 256 pixels are 40 microns wide and 450 microns tall and are spaced at 50 m nternal to th e s ensor is a ther moelectric c ooler the rmal s ensing el ement f temperature f eedback and s tabilization an d a n i ntegrated c ircuit s pecifically designed to i nterface with photoconductive elements T he process f or m anufacturing the ph otonductive film inv olves wet c hemical deposition onto a substrate and th en delineation of the elements This process is relatively straightforward using standard photolithographic techniques and can produ
71. xel StoreAll ReadPWM SuppressErrors ReadTemp SyncPC RestoreAll TECoolerPower CSI 8085 8 08 Germany and other countries LASER COMPONENTS GmbH Phone 49 8142 2864 0 Fax 49 8142 2864 11 info lasercomponents com Great Britain LASER COMPONENTS Uk Ltd Phone 44 1245 491 499 Fax 44 1245 491 801 info lasercomponents co uk France LASER COMPONENTS S A S Phone 33 1 3959 5225 Fax 33 1 3959 5350 info lasercomponents fr Several of these functions simply perform calculations that are convenient for a particular application Calculation Functions ArrayAdd Adds two single dimension arrays ArrayPercentDiff Percent difference between two single dimension arrays ArraySubtract Subtracts two single dimension arrays Flux P Integrates Plank s blackbody equation in Photons sececm esr Integrates Plank s blackbody equation in Watts cm esr The remainder of the functions are involved with controlling the array Many of these have default conditions that are usually left at their default value so there is another subset of functions that are most commonly used for systems that use a single array connected to a computer Common Functions CloseDevice Closes communication with the device This should always be the last command sent DoCalibrate Calibrates the array setting the DAC coefficient array of correction values for each pixel In the default condition Global Skim will not be used and DAC Vh and VI will be

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