光傳感器：概述

　　光傳感器檢測光并將光能轉換成電信號輸出。一旦轉換成電能，就可以測量紅外輻射到紫外光頻譜源的輻射能。

　　最近，但現在幾乎壓倒應用的光傳感器是在LCD背光控制。在這里，環境光傳感器IC被設計用來在很寬的范圍內檢測亮度，從黑暗到直射的陽光，輸出數據以調節LCD亮度以獲得最佳可見度和更低的功耗。

　　光電傳感器的另一種類型是光電傳感器，它包括通過使用光發射器（通常是紅外線）和光電接收器來檢測物體的距離、缺失或存在的裝置。光電傳感器應用于商業和住宅照明以及安全應用。

　　These and other light sensors fall into two main categories. The first group generates electricity when illuminated and is known as either photovoltaic， converting solar radiation into direct-current electricity， or photo-emissive， which releases free electrons from a light sensitive material such as cesium when struck by a photon of sufficient energy. The second grouping includes those that change their electrical properties in some way， such as a photoresistor （whose resistance decreases with increasing incident light intensity） or a photo-conductor （which varies electrical resistance when subjected to light）。