Research And Implementation Of Parallel Scanning, Anti-light Interference Infrared Touch Module

With the continuous development of computer technology, people pay more attention to the man-machine interactive equipment. Touch technology reflects the intelligent and humanization of the modern computer technology, which does not rely on the traditional input devices such as mouse and keyboards.Infrared touch screens have good performance in accurate positioning and stability. However, there are four serious problems in the infrared touch screen, the interference of strong light,the detection of accuracy,response time of system and multi-touch.This paper conducts the following research:In the first part, according to the high precision problem of infrared touch screen,position of boundary is used to correct coordinate of occluded objects. Then, it is the method of record positions and projection of infrared light that could be used to judge two positions, finding the coordinates of the two points. In addition, according to the research above, new designed infrared touch has good performance in accuracy and multi-touch function, which is particularly useful indoorsIn the second part, firstly, according to the principles and design requirements of automatic window shutter, the infrared receiver is selected as the infrared signal receiver.Secondly, the research of infrared receiver shows that the anti-glare capabilities of it is good while its scanning speed is not better enough. So it is necessary to find out a new method to avoided crosstalk in parallel scanning mode, which could accelerate scanning speed of system. Then, some research was designed to find out the number of channels,which were caused by one scanning channel crosstalk. Finally, the overall scheme was design to make the module which meets the design requirements come true.In the last part, this paper researches the anti-light way using crystal oscillator.Eight kinds of crystal are used to design signal sources of infrared emission diodes, and the same frequency crystals are used to design frequency selective circuits.The module make eight scanning units working simultaneously come true. It enhances the anti-light ability of IR touch screen and solves the problem of interference in parallel scanning mode, reducing scan cycle.