Device and method for improving strong light interference resistance of infrared touch screen

Abstract

The invention provides a device and a method for improving strong light interference resistance of an infrared touch screen. Technology different from the traditional strong light detection is adopted, only 3 signals of 8 PD in each group are adopted, a sampling signal is not amplified, is directly performed with AD conversion and is transmitted to a main control chip, whether strong light irradiation exists can be found obviously in this manner, and the influence degree of the strong light on receiving tubes can be even subdivided, the involved device comprises transmitting tubes and receiving tubes, which are installed in a double-redundancy stagger interval manner, and a control circuit, the device and the method can be used for irradiating the infrared touch screen at any angle when the sunlight illuminance is smaller than 70000 LUX, and the infrared touch screen can still work normally, so that the infrared touch screen can be used in most atmospheric environments.

Description

technical field [0001] The invention relates to an infrared touch screen, in particular to a device and method for improving the anti-interference of the infrared touch screen under strong light irradiation. Background technique [0002] Due to its stability, the infrared touch screen has become the preferred touch solution in various harsh environment applications. However, in the case of direct sunlight, the infrared touch screen will fail to recognize the infrared touch screen due to the strong light saturation of the infrared receiving transistor. [0003] The existing anti-glare infrared touch screen usually adopts two schemes: first, adopt the method of reducing the probability of sunlight exposure by moving the infrared receiving transistor (PT for short) backward (see attached figure 1 shown), this method has considerable limitations, such as the possibility of direct sunlight interference, and the anti-light effect is very poor; second, the infrared emitting diode (...

AI Technical Summary

Problems solved by technology

like figure 2 As shown, the staggered layout method of LED and PT is adopted, the incident orientation of strong light is judged by analyzing the sampling value, and then the rotation of the opposite side of the transmitting tube and the receiving tube is carried out to avoid sunlight, but this method cannot judge that the sunlight quickly passes over the two sides. In the case of strong reflection or scattering of sunlight, two opposite receiving edges are irradiated, and because the ambient light intensity changes randomly, the parameter characteristics of each LED and PT of the touch screen are different. There are differences, and it is easy to make mistakes in the judgment of strong light

[0006] The traditional strong light detection method is to analyze and judge the data through complex algorithms (statistical average, difference, mean square error, etc.), but because the amplitude of the amplified sampled signal is close to the maximum value of AD conversion (the original sampled signal needs to go through a thousand levels The above multiples can only be used after magnification), and the inconsistency of the transmitting tube and the receiving tube itself and the installation directly lead to the accuracy of the complex algorithm to judge the strong light

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