通过运动检测节省电池的背光控制

　　通过运动检测节省电池的背光控制

　　关闭便携式产品上的LCD背光，如智能手机、相机、平板电脑和笔记本电脑，可以提供可观的节电和延长宝贵的电池寿命。运动检测是确定设备是否真正空闲或需要保持发光的几种方法之一。例如，如果有人靠近，很可能该设备正在使用中，例如。

　　近距离和环境光传感器的结合正在成为一种流行的技术选择。如果环境光很高，则显示器不需要处于满功率状态。一个创新的消费应用程序是无线蓝牙激活的罗技键盘（见图1）。轻松连接到PC，笔记本电脑或智能手机，背光键的设计是易于阅读在任何光线水平。环境光传感器可以根据房间光线的大小自动调节照明水平。内置的接近传感器检测用户的手接近键盘和打开照明。

　　Figure 1： Backlit displays on smartphones， tablets， notebooks， and even this illuminated keyboard from Logitech， can be controlled through the combination of motion/proximity sensors and ambient light sensors.

　　Another approach is the use of smart accelerometers to detect linear motion to determine whether a portable device is simply being transported， or is about to be activated. A digital camera， for example， could turn off the display when motion is detected indicating it is no longer in use. While in a smartphone， motion detected after inactivity could indicate the device is about to be used.

　　This article will highlight some of the integration and user-interface issues associated with these technologies. It will also review some recently introduced devices such as theTSL2772 family of light and proximity sensors from TAOS， the MAX44000 combined sensors from Maxim Integrated and the SFH 7773 hybrid sensor from OSRAM Opto Semiconductors， as well as the iNEMO range of LIS331 3-axis accelerometers with embedded microcontroller， from STMicroelectronics.