Short-wave Infrared Photoelectric Detection System

• Main Authors: Kuo-Che Chien, 簡國哲
• Other Authors: DER- CHIN CHEN
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/31115949038042481536

碩士 === 逢甲大學 === 資訊電機工程碩士在職專班 === 100 === In this study, a simple electric optical measurement system applicable for the wavelength range of 780nm to 1600nm has been established. This system is mainly composed of three units which include a transmitter, a receiver and signal processing circuit. The transmitter uses pulse driven circuit to drive short wave infrared laser and produce short wave infrared pulsed light. The receiver consisting of AlGaAs photo detector, signal amplification circuit, and band-pass filter circuit detects short wave infrared light. The detection wavelength range of this device is from 900nm to 1700nm, the operating voltage of short wave infrared source is from 2.6V to 3.5V, and the reading resolution of device is 0.01V. After the system has been developed, we measure the optical transmittance of 980nm and 1550nm wavelength in order to confirm system stability. Through the results of the experiment, the average transmittance of sapphire and B270 optical plate is 73.5% and is 76.5%, respectively. This system pioneered on sliced fruit shortwave infrared measurement technology can simply control the quality of fruit by measuring the transmittance of sliced fruit that identifies whether the quality of fruit is good or bad. As long as developed in the future, the fruit reflection measurement will have great advancement in analyzing the quality of fruit merely from its appearance. The additional advantages of this system contain the band pass filter circuit, the unsophisticated optical systems, and the pulsed modulation laser light source which is not easily interfered in the external environment.