Method for recognizing touch points by using acoustic wave touch screen

A touch screen and touch point technology, applied in the input/output process of data processing, instruments, electrical digital data processing, etc., can solve the problems of circuit complexity, cost, signal frequency, occurrence time, strong and weak uncertainty, processor Deal with problems such as higher requirements for capacity, achieve the effect of reducing product cost, improving anti-interference ability, and convenient processing and debugging

Active Publication Date: 2012-06-13
GENERALTOUCH TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, these inventions are based on the passive reception of signals generated by touch, and the uncertainty of the frequency, occurrence time, and strength of the signals is large, and the processing capability of the processor is relatively high.
[0009] In

Method used

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  • Method for recognizing touch points by using acoustic wave touch screen
  • Method for recognizing touch points by using acoustic wave touch screen
  • Method for recognizing touch points by using acoustic wave touch screen

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0047] The acoustic pulse signal emitted by the transducer reaches the touch body after a time t, and after being reflected by the touch body, it is reflected back to the transducer that is already in the receiving state after the same time t. For the touch screen body, due to the surface acoustic wave pulse signal The transmission speed V is constant, so the distance L from the touch body to the transducer is: L=V t.

[0048] For a single transducer, only the distance between the transducer and the touch body can be determined, but the plane position of the touch body cannot be determined. Therefore, the orientation of the touch body needs to be determined.

[0049] For transducers with strong directivity and small emission angle, it is necessary to scan the touch area of ​​the screen body by mechanical or electronic means. When scanning to the specified angle A, the emission signal is reflected back to the transducer due to the reflection of the touch body. , the distance L ...

Embodiment 2

[0057] A transducer with a large emission angle is used to emit to the touch area at the same time. The touch body can reflect the sound wave propagating along the surface in any direction of the screen. It does not need to scan, and the distance between the touch body and the transducer can be determined, but The position of the touch body cannot be determined. At least two transducers must be used, which are arranged on the sides or / and corners outside the touch area. The geometric relationship between the body and the transducer determines the touch position of the touch body. This method has a large emission angle, relatively dispersed energy, does not require scanning and emission of signals, and has a simple and reliable circuit or structure.

[0058] Without considering the size of the touch body, L0 is the known distance during design, and L1 and L2 are the distances actually detected. According to the geometric relationship, the touch position X and Y are determined b...

example 3

[0063] When there is more than one touch body, different touch bodies will generate more than one echo, such as image 3 In order to identify the echoes of the same touch object, multiple transducers can be used, such as Figure 4 , increase the redundancy of detection, or identify multiple touch objects at the same time.

[0064] When designing, the distances L0, Lx, and Lxy between the transducers are fixed and known, and the distances L1, L2, L3, L1a, L2a, and L3a from the touch body to the transducer are detected by the controller. The position coordinates can be obtained by calculating the geometric position relationship between the touch body and the transducer. In order to simplify the amount of calculation, the coordinate relationship data can also be tabulated and obtained by looking up the table.

[0065] As shown in the figure, the touch positions X and Y of the touch body 2 can be respectively calculated from three sets of data (L1, L2, L0), ( L2, L3, Ly), (L1, L...

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Abstract

The invention discloses a method for recognizing touch points by using a surface acoustic wave touch screen. The method comprises the following steps of: based on a back wave positioning principle, reflecting a surface acoustic wave transmitted by a transducer when the surface acoustic wave meets a reflector (or a touch body), and calculating to obtain a distance between the touch body and the transducer by measuring time elapsed after the surface acoustic wave is transmitted by the transducer, reflected by the touch body and then is reflected back to the same transducer, according to a propagation velocity of the acoustic wave, thereby locating the touch body. According to the requirements of a touch system, different numbers of transducers can be configured so that one-dimensional and two-dimensional coordinate positioning of a single or/and multiple touch bodies is realized.

Description

technical field [0001] The invention relates to an acoustic wave touch positioning sensing system, in particular to a method for identifying a touch point on an acoustic wave touch screen. Background technique [0002] With the development and popularization of computer technology, the application fields are becoming more and more extensive, and the demand for human-computer interaction technology equipment is increasing. As a typical human-computer interaction device, the touch screen is increasingly in demand. Common touch screens include resistive screens, capacitive screens, infrared screens, and acoustic wave touch screens. The acoustic wave touch screen has outstanding advantages such as stability, high light transmittance, and scratch resistance, and is widely used. [0003] Ordinary acoustic wave screens are composed of transmitting / receiving transducers in pairs. After the acoustic wave signal is emitted from the transmitting transducer, it is reflected by the refl...

Claims

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Application Information

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IPC IPC(8): G06F3/043
Inventor 张定庆钟德超林立
Owner GENERALTOUCH TECH
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