光传感器：概述

　　光传感器：概述

　　光传感器检测光并将光能转换成电信号输出。一旦转换成电能，就可以测量红外辐射到紫外光频谱源的辐射能。

　　最近，但现在几乎压倒应用的光传感器是在LCD背光控制。在这里，环境光传感器IC被设计用来在很宽的范围内检测亮度，从黑暗到直射的阳光，输出数据以调节LCD亮度以获得最佳可见度和更低的功耗。

　　光电传感器的另一种类型是光电传感器，它包括通过使用光发射器（通常是红外线）和光电接收器来检测物体的距离、缺失或存在的装置。光电传感器应用于商业和住宅照明以及安全应用。

　　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）。