并行扫描抗强光红外触控模块的研究与实现

发布时间：2018-02-04 17:44

本文关键词： 红外触摸屏并行扫描抗强光红外解调器　出处：《电子科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着计算机技术的不断发展,人们对信息技术的要求也越来越高,其中快捷方便地与智能设备的信息交互也受到人们的广泛关注。触摸技术脱离了传统的鼠标、键盘等输入设备,体现现代计算机技术的智能化和人性化的特点。红外触摸屏在清晰度,精确定位,稳定性等方面具有很大优势,但红外触摸屏仍具有以下四个重要难题:外界光干扰、触摸检测精度、系统响应时间以及多点触摸检测。本论文针对上述问题进行如下研究:首先根据红外触摸屏触摸精度不高的原因,研究红外触摸屏提高触摸精度的方法。研究中通过加入触摸点边界的检测进行触摸位置的修正,从而实现触摸屏检测精度的提高。针对红外触摸屏多触点问题,采用触摸记录和投影的方法,找出触摸点相对位置,实现伪点的剔除。并根据红外触摸屏工作原理,设计了适用于室内环境下高精度、多触点功能的红外触摸屏。然后根据智能百叶窗的实现原理和触控模块的设计要求,选择红外解调器作为红外信号接收器。通过研究红外解调器的抗强光能力和扫描速度,得出解调器抗强光能力良好但扫描速度慢的结论。根据触摸模块精度要求和解调器扫描速度慢的特点,提出了一种间隔的方式避开管间串扰,实现并行扫描以提高扫描速度的方法,并对该方法中需避开串扰的通道数进行了推导和论证。接下来给出了触控模块的设计方案,并对方案中的硬件和程序进行设计,实现模块可拼接、可批量生产的功能,最后对触控模块性能进行验证。最后针对红外触摸屏抗强光能力弱的特点,选择无源晶振滤波器作为选频电路滤除强光干扰的方案。对晶振的频率特性进行研究,设计无源晶振抗强光单元,并对单元进行强光测试和扫描速度进行测试。根据无源晶振单元抗强光能力强而扫描速度慢的问题,提出一种基于多种频率的无源晶振并行扫描方式抗强光模块方案。方案中使用8个不同频率的无源晶振分别作为并行扫描抗强光模块中红外发射管的信号源和红外接收电路的选频器,实现了8个扫描单元同时工作。保留了无源晶振单元的抗强光能力,解决相邻8个红外发射管同时工作而产生的串扰问题,从而提高红外管的平均扫描速度。并通过实验对模块抗强光干扰能力和滤除管间串扰能力进行验证。
[Abstract]:With the development of computer technology, people are demanding more and more information technology, among which the information interaction with intelligent devices is paid more and more attention. Touch technology is away from the traditional mouse. Keyboard and other input devices reflect the intelligent and humanized characteristics of modern computer technology. Infrared touch screen has great advantages in definition, precise positioning, stability and so on. However, the infrared touch screen still has the following four important problems: external light interference, touch detection accuracy. The system response time and multi-touch detection. In this paper, the above problems are studied as follows: firstly, according to the reason that the touch accuracy of infrared touch screen is not high. The method of improving touch accuracy by infrared touch screen is studied. The touch position is modified by adding touch point boundary detection, so as to improve the precision of touch screen detection. Aiming at the multi-contact problem of infrared touch screen. By using the method of touch recording and projection, the relative position of touch point is found, and the pseudo point is eliminated. According to the working principle of infrared touch screen, high precision is designed for indoor environment. The infrared touch screen with multi-contact function. Then according to the realization principle of the intelligent shutter and the design requirements of the touch module. The infrared demodulator is selected as the infrared signal receiver. The anti-glare ability and scanning speed of the infrared demodulator are studied. According to the precision requirement of touch module and the characteristic of slow scan speed of demodulator, a way to avoid crosstalk between tubes is proposed. The method to realize parallel scanning to improve the scanning speed, and the number of channels to avoid crosstalk in this method is deduced and demonstrated. Then, the design scheme of touch control module is given. The hardware and program of the scheme are designed to realize the function of module splicing and batch production. Finally, the performance of touch module is verified. Finally, the characteristics of infrared touch screen with weak anti-glare ability are pointed out. The passive crystal oscillator filter is chosen as the scheme to filter the strong light interference in the frequency selective circuit. The frequency characteristic of the crystal oscillator is studied and the passive crystal oscillator anti-strong light unit is designed. According to the problem that the passive crystal oscillator unit has strong anti-glare ability and slow scanning speed. A parallel scanning scheme of passive crystal oscillator based on multiple frequencies is proposed, in which eight different frequencies of passive crystal oscillator are used as the signal source and red source of infrared emitter respectively. A frequency selector for an external receiving circuit. Eight scanning units are realized to work simultaneously, and the passive crystal oscillator unit has the ability to resist strong light, which solves the crosstalk problem caused by 8 adjacent infrared emitters working at the same time. In order to improve the average scanning speed of the infrared tube, the ability of resisting the strong light interference and filtering the crosstalk between the tubes is verified by experiments.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN219;TN873

【参考文献】