A TDR touch screen and a touch scanning locating method

Abstract

The invention provides a TDR touch screen comprising a touch area and a plurality of parallel U-shaped wires which are arranged in the touch area and are independent of one another. An insulation layer is arranged over the U-shaped wires. The TDR touch screen also comprises a signal transmitter, 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; the signal transmitter is connected with the scanning drive circuit. The invention also provides a touch scanning locating method suitable for the TDR touch screen. The method is characterized in that the scanning drive circuit drives the signal transmitter to transmit step signals to the input ends of the U-shaped wires successively and the reflection signal detector receives reflection signals of the input ends successively and correspondingly; touch positions are located based on the time delay from the input of the step signals to the reception of the reflection signals. According to the invention, multi-point touch control is realized, the touch control algorithm difficulty is reduced, and the touch control locating precision is improved.

Description

technical field [0001] The invention relates to the field of touch screens, in particular to a time-domain reflectometry (TDR)-based scanning touch screen and a touch scanning 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 ad...

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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