Photoelectric Identification Technology Based On MEMS Infrared Source Array

Focusing on the photoelectric identification technology based on MEMS infrared sourcearray, the thermal radiation characteristics and convergence radiation controlling methods ofMEMS infrared source device, coded modulation processing and the driving system circuitdesign of infrared source array and the photoelectric identification system aided designsoftware used to calculate the radiation distance were researched. The theoretical foundationand technical programe aimed to the fields of near the ground space wireless communications,battlefield target identification friend or foe (IFF), complex environment disaster relief,industrial and mining production safety and infrared mass spectrometry were established.The MEMS infrared source is a kind of electrochromic heated radiation devices based onsemiconductor materials, with the radiation characteristics of mid-infrared narrowband stableoutput within3~5μm. The systematic test analysis indicated it can be frequency modulatedwithin1~50Hz. Under5.8V driving voltage, its radiated output power was65.7mW and theelectro-optical conversion efficiency was up to9.76%. To solve the problem about theexcessive radiation divergence angle of the infrared source, an infrared condenser mirrorbased on superhard aluminum alloy was designed and fabricated. The radiated power anglewas convergence controlled effectively and the collimated radiation intensity was increasedby86%. A collimated radiation len was designed with the Zemax optics simulation software.With it the full collimator outgoing of radiation light couled be impletemented aftertheoretically analysised. The photoelectric identification system computer-aided designsoftware based on VB programming was developed. The LOWTRAN kernel was used to bekey algorithm to calculate the average atmospheric transmittance of infrared radiation. Theintegral calculation of infrared radiation intensity based on Simpson integral formula and thequick comparison approach matching algorithm for the radiation distance calculation were proposed. Calculated and analysised by this software, the theoretical radiation detectiondistance of the infrared source unit was about7924m, of which was fitted up to99.7%withthe theoretical calculation results. The fast digital program controlled adjustable linear voltageregulator ICs ADP3336with high precision and low dropout was selected to drive the infraredsource unit. The driving voltage accuracy was within1.8%and the driving efficiency was upto80.1%with the driving power of673mW of which could meet the load capacity of onesource unit absolutely. Arranging the MEMS infrared sources into5×5plane point array, thecomposite space-time two-dimensional dynamical coded modulation method combined withpoint array patterns and modulation frequency was proposed. The photoelectric code quantityof information was up to800Mb with the error free transmission speed of1.25kb/s. The pointarray coded pattern structures and dynamic graphic switching frequency of the photoelectricidentification system with infrared source array were controlled by field-programmable gatearray (FPGA). The modulation and control of the infrared photoelectric signal with highprecision and high reliability was impletemented with it. Finally, the dynamic infrared pointarray patterns were tested by infrared camera and a good result of the photoelectricinformation recognition experiment was acquired.