Signal processing and control method and signal processing and control device of infrared touch screen

Abstract

The invention provides a signal processing and control method and a signal processing and control device of an infrared touch screen. The signal processing and control method includes: under control of a main control unit, a drive circuit drives an infrared light-emitting tube to emit infrared; an infrared receiving tube receives a light signal sent by the infrared light-emitting tube, converts the light signal to a voltage signal and outputs the voltage signal to a signal amplification circuit; the signal amplification circuit amplifies the voltage signal and outputs the voltage signal to an analog-digital conversion circuit; the analog-digital conversion circuit coverts the amplified voltage signal to a digital voltage value and outputs the digital voltage value to the main control unit; and the main control unit regulates light-emitting duration of the infrared light-emitting tube and / or amplification factor of the signal amplification unit according to the size of the received voltage value. The problem of limitation that an automatic gain control circuit is simply used for regulating the amplification factor is solved, and additionally the problem of mass production due to inconformity of the infrared light-emitting tube and the infrared receiving tube is solved.

Description

technical field [0001] The invention relates to the field of infrared touch screens, in particular to a signal processing and control method and device for an infrared touch screen. Background technique [0002] The infrared touch screen is a circuit board frame installed in front of the display. Infrared emitting tubes and infrared receiving tubes are arranged on the four sides of the circuit board frame. Generally, the infrared emitting tubes and infrared receiving tubes are arranged on two opposite sides of the frame side, thus forming a crossed infrared matrix. When the user touches the screen, the finger will block the horizontal and vertical infrared rays passing through the position, and judge the position of the touch point on the screen according to the blocked infrared rays. [0003] Due to the inconsistency of the infrared emission tube itself, its emission power is a range value. Taking the IR51C-L302 model of Everlight Company as an example, its emission power ...

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Problems solved by technology

[0004] In order to solve this inconsistency problem, manufacturers of infrared emitting tubes and infrared receiving tubes will strictly classify products, which will add a process link and increase production costs

Another solution is to add an automatic gain adjustment (AGC) function in the circuit design to adjust the signal amplification factor. This method can adjust the signal with little difference, but if the signal difference is large, it will cause signal oscillation. , at the same time, if the signal is relatively weak and the magnification factor is large, the noise is also amplified while amplifying the signal, which is manifested on the infrared touch screen as disconnection or jumping points, and the signal stability is not good

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