光傳感器：概述

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

　　最近，但現(xiàn)在幾乎壓倒應(yīng)用的光傳感器是在LCD背光控制。在這里，環(huán)境光傳感器IC被設(shè)計(jì)用來(lái)在很寬的范圍內(nèi)檢測(cè)亮度，從黑暗到直射的陽(yáng)光，輸出數(shù)據(jù)以調(diào)節(jié)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(fā)射器（通常是紅外線）和光電接收器來(lái)檢測(cè)物體的距離、缺失或存在的裝置。光電傳感器應(yīng)用于商業(yè)和住宅照明以及安全應(yīng)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）。