TMD2771X sensor has three features: ambient light, proximity sensor and infrared LED. It plays a main role in mobile phone about two aspects. First, this sensor is applied to detect the current brightness of ambient light, adjust automatically the brightness of backlit with software according to the current brightness of ambient light to adapt to ambient brightness, and make the brightness of backlight gentle to protect vision and save power. Second , that is proximity sensor. Judge whether the mobile phone is close to face by the reflex of LED launching infrared and the reception of built-in PD, and thereby determined the status of backlit and touch screen button ON/OFF.
Its biggest advantage lies in integrating infrared transmitting tube inside without external support of LED. Besides, the sensor with three features has integrated transceiving and minimized design without limitation of space. Its structure is simpler.