高靈敏度光點位置偵測器

High-sensitive light spot position sensing detector

陳琇瑛(Shiou-Ying Chen)

指導教授 ： 郭文凱

國立虎尾科技大學/電機資訊學院/光電與材料科技研究所/碩士(2008年)

摘要

本論文提出一個高靈敏度且可區分背景光之光點位置偵測器，主要是利用一個二維光感測陣列（19 × 19 pixels）、四組轉阻放大器（trans-impedance amplifier）及鎖相放大電路（Lock-in Amplifier）所構成。此位置偵測器之所以可以區分背景光是由於本論文將待測的光點光源作調變，使得待測測的光點呈現一個閃爍的狀態，這裡我們稱之為?閃爍光點?，利用閃爍光點與背景光頻率的不同（一般而言，背景光之閃爍頻率通常遠低於待測光點之頻率），並藉由鎖相放大器僅偵測與閃爍光點頻率相同之特性，排除背景光，來達到區分背景光及閃爍光點的目的。故此光點位置偵測器可改善室外量測因天候不佳所造成的準確度誤差。該位置偵測器使用TSMC 0.35μm製程模擬製作，可偵測之最小光電流為1 nA，消耗功率低於150 mW，且整體線性度可高達70%。

關鍵字

鎖相放大器 ； 位置偵測器

並列摘要

This paper proposed a light spot position sensing detector which has high sensitivity and is capable of separating the background light. We uses a photo- transistor matrix (19 × 19 pixels), a trans-impedance amplifier, and a lock-in amplifier to form this position sensitive detector. This detector extracts the modulation light spot form the background light and utilizes a analog computation circuit to obtain the light spot position. The circuit use TSMC 0.35 μm process model for simulation and results show that the smallest detectable photo current is 1nA, the consumed power is lower than 150mW, and the overall linear is as high as 70%.

並列關鍵字

lock-in amplifier ； position sensitive detector

參考文獻

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