红外触控屏的接收单元抗干扰新技术及其验证

New anti-jamming technology and verification of infraed touch screen receiver unit

红外触摸屏通过发射接收红外光进行工作,对环境光照因素的变化比较敏感。在有外界强光照的环境中使用红外触摸屏会受到极大干扰,导致红外接收管接收到的光强发生异常,从而引起误动作。本文研究了采用高频红外光的发射与接收,以锁相放大方式滤除太阳光的干扰频段分量,实现了红外触控屏的抗直接照射的阳光干扰的方法与验证结果。此外,通过改进了锁相放大器的解调算法,去掉传统的锁相放大后级所必须的滤波电路,电路更加简洁、可靠。经硬件平台的实际验证,选频Q值可以达到145.985,并能在50 000lx的光强下正常工作。该算法能够实现很好的选频和抗强光效果,达到抗干扰目的。

Infrared touch screen works through transmitting and receiving infrared light, which is sen- sitive in the change of environmental illumination factors. Infrared touch screen will be disturbed in the external strong light environment, leading that the infrared receiving tube receives light intensity ab- normally and it may cause malfunction. First, high frequency infrared light transmission and reception is used to filter band component of sunlight interference by the method of lock-in amplifier. Second, the method of the direct exposure of sunlight anti-interference has been realized and its result is proved. In addition, the filter circuit which traditional amplification after stage haves is removed by im- proving the demodulation algorithm of the lock-in amplifier. This algorithm makes the circuit more simple and reliable. The hardware platform of the actual experiment indicates that frequency selection Q is 145. 985 ,and it can work in the 50 000 lx light environment availably. It proves that the algorithm can achieve good frequency selection,and meet the requirement of anti-glare effect and anti-jamming.