激光尘埃粒子计数器微型光学传感器的研究

研制成功便携式激光尘埃粒子计数器的核心部件———微型光学传感器。该传感器采用直角散射光收集形式,以高功率半导体激光器作为光源,同时采用高性能的PIN型光电二极管作为光电探测器。散射光收集系统为单一大数值孔径的球面反射镜,其对粒子散射光的收集角范围从20°到160°。粒子散射光信号是脉冲信号,其频谱成份主要在高频段,所以在PIN型光电二极管后用一个带通式前置放大器来消除外界的低频噪声,根据米氏散射理论计算了该光学传感器的光散射响应特性,并用聚苯乙烯标准粒子实测了该光学传感器的性能。结果表明,该系统具有高的信噪比、计数效率和尺寸分辨本领。

Study of Miniature Optical Sensor for Laser Particle Counter

A miniature optical sensor, the core of a miniature laser aerosol particle counter, has been developed. The optical system of the sensor is a right-angle scattering optics. A high-power laser diode module is used as the light source, and a PIN photodiode with high performance is used as the photo-detector. By using a reflective spherical mirror with large numerical aperture, the light scattered by individual particles is collected over a large angular range of 20° to 160°. The scattered light signal from the particle is short pulse, which consists mainly of high frequency components. A band-pass preamplifier is used to eliminate lower-frequency eletromagnetic interference from external environment. The light scattering response characteristics of the sensor are calculated based on Mie scattering theory. The sensor performance has been tested with standard par5ticles of polystyrene latex, the results show that the sensor has high signal-to-noise ratio, counting efficiency, and size resolution.