TDR touch screen and touch positioning method

Abstract

The invention discloses a TDR touch screen. The TDR touch screen comprises a touch area and a plurality of parallel and mutually independent U-shaped wires arranged in the touch area, and an insulting layer is arranged above each U-shaped wire; the TDR touch screen further comprises a signal transmitter, a signal output detector, a reflection signal detector and a scanning drive circuit; the input ends of the U-shaped wires are connected with the signal transmitter and the reflection signal detector respectively, the signal transmitter is connected with the scanning drive circuit; the output end of each wire is connected with the signal output detector. The invention further discloses a touch positioning method suitable for the TDR touch screen. By adopting the TDR touch screen and touch positioning method disclosed by the invention, multi-point touch can be realized, the difficulty of a touch algorithm is lowered, and the touch positioning accuracy is improved.

Description

technical field [0001] The invention relates to the field of touch screens, in particular to a scanning touch screen based on time domain reflectometry (TDR) and a touch positioning method. Background technique [0002] Existing touch screens mainly include resistive touch screens, capacitive touch screens, and infrared touch screens. [0003] Resistive touch screens are mainly used in low-end products, usually only have a single touch function. Capacitive touch screens are widely used in various electronic products, but there are problems such as complex manufacturing process and high cost when applied to super-large-sized products, so large-sized products usually use infrared touch screens. Infrared touch screens need to arrange infrared emitting tubes and infrared receiving tubes around the screen, resulting in large volume and thickness, and the accumulation of dust will cause abnormal touch sensing. [0004] In order to solve the above problems, the prior art adopts a...

AI Technical Summary

Problems solved by technology

[0006] 1. The signal attenuation reflected at the end of the transmission line is large, requiring a very high input step signal level, resulting in increased radiation; at this time, the distributed resistance of the transmission line cannot be ignored, and additional variable calculation is required;

[0007] 2. The serpentine transmission line will have multiple large-angle inflection points, and its impedance will also have multiple mutation points, which requires a higher algorithm for measuring impedance changes

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