The Multi-touch Anti Glare Interfere With The Design And Verification Of The Infrared Touch Screen

Touch screen as an interactive input device is extensively applied because of the simple operation and the flexible feature. Infrared touch screen is one of them. Infrared transmitters and infrared receivers are placed on the screen edges and microprocessor driving circuit is used to connect to the infrared transmitters and check the appropriate infrared receivers, which forms the infrared crossed arrays. Films are not needed, and the optical transmission is 100 percent. The current, voltage and electrostatic interference can make no difference on the screen, and so it is suitable for harsh environmental conditions. But the infrared touch screen is greatly affected by the light interference, causing the accidental operation easily. Meanwhile it is not high in the resolution of application. These two points above seriously constraint it in the market, especially in the development of applications in airborne human-computer interaction. At the same time, multi-points resistive touch screen and capacitive touch screen have gradually come into the market, which makes the performance of the infrared touch screen require much more.Based on the improvement of the infrared touch screen above, the design of the multi-touch, anti-intense interference, high resolution infrared touch screen design is presented and proved in the dissertation.In this dissertation, the emission module and the receiving module are controlled by the microprocessor chip to make the infrared receivers keep accord with the infrared transmitters. And the light signal received is graded. According to the relationship between the position of the touch and the integrity of the light signal, the high resolution is achieved, 2048 by 768; in front of the infrared receiver, the light collimation channels sensitive to the direction of propagation of light are installed to weaken the optical jamming around the environment. At the same time, according to detecting the light signal received in the different state, the threshold of the touch is determined. The threshold is adjusted real-timely to response to the change of the light around the environment. By the processing above, touch screen can normally work in the 17600 lx light and the ability of the anti-highlight jamming can nearly be enhanced by 3; after testing all the positions of the fingers touch, the false touch points are removed to get the exact coordinates and get the multi-touch infrared touch screen. With the programming of VC, the algorithm which makes the mouse smoothing process, orientation, click, double-click, identifies hand movements and appoints the area where the brightness will be modulated is researched.