【作者】 李毅；

【导师】 黄子强；

【作者基本信息】 电子科技大学 ， 光学工程， 2013， 硕士

【摘要】 随着信息技术的发展，人们需要更便捷的方式与智能设备进行交互，触摸屏技术作为人机交互设备的一种得到了蓬勃的发展。红外触摸屏不需要在显示屏上附加薄膜，因而透过率100%，并且拥有不易受电磁场，静电干扰的优点，所以适用于环境恶劣的工作场合。但是红外触摸屏依赖红外光作为工作媒介，而红外波段在太阳光的能量分布中约占50％，太阳光将干扰红外触摸屏的正常工作。针对上述缺点，本文对红外触摸屏的工作原理和设计实现进行深入研究，首先研究适用于室内光环境的红外触摸屏，在此基础上，研究能够在高空强环境光下工作的红外触摸屏，提出并行触摸扫描，选频接收的可扩展，抗强光红外触控模块，根据选频接收方式不同，又分别研究无源晶体谐振器选频接收和数字互相关锁相放大选频接收两个方案。首先研究适用于室内光环境的红外触摸屏的工作原理和设计实现，测试分析其在环境光变化时的工作性能。方案的特点是：由ARM7控制一一对应的165对红外发射二极管和光电三极管顺序的点亮和数据接收，在ARM7的接收数据处理中使用动态阈值的方式使红外触摸屏能在室内370lux光强环境下正常工作。然后研究无源晶体谐振器选频接收的并行扫描红外触摸屏的工作原理和设计实现，测试分析其抗强光性能。方案的特点是：使用C8051F930将接收数据的量化和数据处理集成到一个芯片上，将整个红外触摸屏分割为一系列独立工作的扫描单元，整个红外触摸屏的顺序扫描改变为各个扫描单元的并行扫描；扫描单元使用扩展UART通信协议与主控模块通信；使用光电二极管作为光电转换器件避免接收信号的饱和；利用无源晶体谐振器的逆压电——压电效应构成窄带滤波实现选频接收。实验证明该方案能够在环境光强45Klux下正常工作。最后，基于适用于室内光环境的红外触摸屏研究中提出的触摸坐标产生方法，无源晶体谐振器选频接收并行扫描红外触摸屏研究中提出的扩展UART协议实现并行扫描和模块扩展的方法，研究使用互相关锁相放大选频接收的可扩展、抗强光红外触控模块的工作原理和设计实现，测试分析其抗强光性能。方案的特点是：使用PSOC5可编程片上系统芯片实现数字互相关锁相放大，提高集成度并且实现灵活配置对不同频率信号的选频接收；改进光电二极管的光电转换电路，使用多电压域的方式提高饱和电压限值。实验证明该方案能在环境光强100Klux下正常工作。更多还原

【Abstract】 With the development of information technology, people need a more convenientway to interact with smart devices. As a human-computer interaction device, touchscreen technology has been booming recently.Infrared touch screen does not require additional film on the display, so thetransmittance is100%. And infrared touch screen is less susceptible to electromagneticfields and electrostatic interference. It is suitable for working in harsh environment.Infrared touch screen dependent infrared light as working medium, infrared lightcomprise50％energy of the sunlight. So the sunlight can interface the operation ofinfrared touch screen.To solve the above shortcoming, this paper researches the operation principle,design and implementation of infrared touch screen. First research the infrared touchscreen which is suitable for indoor light environment. Base on that, research the infraredtouch screen which can work under high altitude strong light interference and propose aparallel scanning, received frequency selective infrared touch module. According tofrequency selective method, this paper researches crystal method and digitalcross-correlation phase lock amplification method to select received frequency.First, this paper researches the working principle and implementation of theinfrared touch screen which is suitable for indoor light environment, analyzes itsperformance while environmental light changing. The ARM7controls165pairs ofone-to-one corresponding infrared emitting diode and phototransistor transmitting andreceiving data sequentially. While data processing, this paper uses dynamic thresholdmethod to insure the infrared touch screen can work under370lux light intensity.Second, this paper researches the working principle and implementation of parallelscanning infrared touch screen which uses crystal to select certain frequency receivedsignal, analyzes its anti-light interference performance. Use C8051F930quantifying andprocessing received data on a single chip. Divide entire infrared touch screen intoseveral working independently scanning units. Thus the sequentially touch scanning ofentire infrared touch screen changes to the parallel scanning among scanning units. The scanning unit use extended UART protocol to communicate with master module. Usephotodiode as photoelectric conversion device to avoid saturation of received signal.Use converse piezoelectric-piezoelectric effect of passive crystal resonator toconstitute a narrow-band filter to achieve frequency selecting. Based on experiment thisinfrared touch screen can work under45Klux light intensity.At last, by using the touch coordinates generation method proposed by infraredtouch screen suitable for indoor light environment and the extended UART protocol toachieve parallel touch scanning and extensible module proposed by parallel scanninginfrared touch screen, this paper researches the working principle and implementation ofscalable, anti-light interference infrared touch module which uses cross-correlationphase lock amplification theory to select certain frequency received signal, analyzes itsanti-light interference performance. Use PSOC5, a programmable system-on-chip chip,to achieve digital cross-correlation phase lock amplification which can configurereceived frequency flexibly. Improve photodiode photoelectric conversion circuit bymulti-voltage domain method to increase the saturation voltage limit. Based onexperiment this infrared touch screen can work under100Klux light intensity.更多还原