CN103761018B

CN103761018B - Scanning method of capacitive touch screen

Info

Publication number: CN103761018B
Application number: CN201410030384.1A
Authority: CN
Inventors: 保罗·格兰德维兹
Original assignee: Suzhou Pixcir Microelectronics Co Ltd
Current assignee: Suzhou Pixcir Microelectronics Co Ltd
Priority date: 2014-01-23
Filing date: 2014-01-23
Publication date: 2020-10-30
Anticipated expiration: 2034-01-23
Also published as: CN103761018A

Abstract

A scanning method of a capacitive touch screen comprises a plurality of conducting wires, when the capacitive touch screen is scanned, one conducting wire is selected to be connected to an exciting device each time, and a plurality of conducting wires are arranged between the conducting wires connected to the exciting device in two adjacent scanning processes. By changing the selection order of the wires connected to the excitation means, the interval between the excitations is increased, and it is easier to detect the change of the sensing signal due to the excitation and the touch.

Description

Scanning method of capacitive touch screen

Technical Field

The invention relates to a capacitive touch screen, in particular to a scanning method of an embedded capacitive touch screen.

Background

With the development of science and technology, electronic products such as touch screens are favored by people due to better human-computer interaction experience, and touch screens are mainly classified into resistive type, capacitive type, infrared type and acoustic wave type according to the types of sensors, wherein the capacitive touch screens are widely applied due to the advantages of supporting multi-point touch, being accurate in positioning, being long in service life and the like.

In the existing capacitive touch screen, a touch panel and a display panel are mainly divided into three combination modes, wherein the first mode is that the touch panel and the display panel are two independent devices in the existing pair and are assembled into the capacitive touch screen by being attached up and down; the second way is to embed the touch panel between the color filter substrate and the polarizer, so that although the thickness of the capacitive touch screen can be reduced to a certain extent, the glass substrate where the color filter is located cannot be thinned, and the space for reducing the thickness in the future is limited; the third way is to embed the touch panel in the liquid crystal pixel, and the capacitive touch screen of this way is lighter and thinner than the first and second capacitive touch screens, conforms to the development rule of touch screens, and is the development direction in the future.

The thin film transistor display is one kind of liquid crystal display, and each liquid crystal pixel point is driven by the thin film transistor behind it, the grid of the thin film transistor in the same row is connected to the same wire, the source in the same column is connected to the same wire, and the wire is generally made of transparent material. In the embedded touch panel, the wires connecting the source and the grid are connected to the touch detection device to realize the touch function, so that the touch screen is lighter and thinner. In view of the above problems, the present invention provides a scanning method capable of eliminating the negative effects caused by the relatively dense arrangement of the wires connecting the source and the gate of the thin film transistor.

Disclosure of Invention

The invention aims to provide a scanning method applied to an embedded touch screen.

In order to achieve the above object, the present invention provides a scanning method for a capacitive touch screen, where the capacitive touch screen includes a plurality of wires, one of the wires is selected to be connected to an excitation end each time when the capacitive touch screen is scanned, and a plurality of wires are spaced between the wires connected to the excitation end in two adjacent scans.

Compared with the prior art, the distance between the excitation of the rising edge and the excitation of the falling edge is increased by changing the selection sequence of the leads connected to the excitation device, the change of the sensing signal caused by the excitation and the touch is easier to detect, and the problem that the leads in the embedded capacitive touch screen are difficult to detect due to the close distance between the leads is solved.

Drawings

FIG. 1 is a schematic view of a capacitive touch screen

Fig. 2 is a schematic diagram of the selection sequence of the first sequential scan.

Fig. 3 is a schematic diagram of the selection sequence of the second sequential scan.

Detailed Description

The present invention will be further described with reference to the following examples.

Referring to fig. 1, an in-cell capacitive touch panel includes a thin film transistor (not shown), wires connecting a gate and a source of the thin film transistor (only the wires connected to the gate are shown in fig. 1), and a touch sensing device connected to the wires. And the conducting wire is connected with the grid electrodes of the thin film transistors in the same row and is connected with the source electrodes of the thin film transistors in the same column. The conducting wires can also be connected in the reverse direction, namely the conducting wires are connected with the source electrodes of the thin film transistors in the same row and connected with the grid electrodes of the thin film transistors in the same column.

The touch detection device comprises an addressing device, a comparison device and an excitation device, wherein the addressing device is used for selecting a lead wire required to be connected to the excitation device and the comparison device, the comparison device receives an induction signal and a reference signal at a receiving end and outputs a result at an output end, and the excitation device is used for providing an excitation signal. When the liquid crystal capacitive touch screen is scanned, one conducting wire is selected by the addressing device to be connected to the exciting device to serve as an exciting end, the other conducting wire is selected by the addressing device to be connected to one input end of the comparing device to serve as a sensing end, and the other input end of the comparing device is selected to serve as a reference end by the reference potential or the conducting wire close to the conducting wire serving as the sensing end is selected to be connected to the other input end of the comparing device to serve as a reference end.

The following describes a scanning method of a capacitive touch screen, taking an example of a reference terminal connected to one end of a comparator.

Referring to fig. 2 and 3, initially, the addressing device selects one conducting wire (1) to be connected to the excitation device, selects the other conducting wire (2) to be grounded, and has a plurality of conducting wires spaced therebetween, preferably, the spacing distance is set according to a distance of a finger, the addressing device selects any third conducting wire except the two conducting wires to an input end of the comparison device, and the reference potential is connected to the other input end of the comparison device. During the first scanning, the conducting wire (1) connected to the exciting device is grounded, the grounded conducting wire (2) is connected to the exciting device, one of the grounded conducting wires forms the excitation of a falling edge, the other grounded conducting wire forms the excitation of a rising edge, and the comparing device compares the induction signal obtained from the third conducting wire with the reference signal to obtain a result. And when the next scanning is carried out, namely the second scanning, the lead (2) connected to the exciting device is grounded, the addressing device selects the fourth lead (3) to be connected to the exciting device, and similarly, one of the leads forms the excitation of a falling edge, and the other of the leads forms the excitation of a rising edge, so as to detect the change of the induction signal, and a plurality of leads are arranged between the lead (2) grounded in the current scanning and the lead (3) connected to the exciting device, namely, a plurality of leads are arranged between the lead (2) connected to the exciting device in the last scanning and the lead (3) connected to the exciting device in the current scanning, namely, a plurality of leads are arranged between the leads connected to the exciting device in two adjacent scanning. And in the same way, in the third scanning, the fourth conducting wire (3) connected to the exciting device is grounded, the addressing device selects the fifth conducting wire (4) to be connected to the exciting device, a plurality of conducting wires are arranged between the fifth conducting wire (4) and the fourth conducting wire (3) at intervals, and the change of the induction signal at the moment is detected, preferably, the intervals between the conducting wires connected to the exciting device and the grounded conducting wires are equal in the third scanning, namely, the number of the spaced conducting wires is equal. In this manner, the first sequential scan is completed. In the second sequential scanning, the leads (5, 6, 7, 8) which are not connected with the exciting arrangement in the first sequential scanning are selected to be connected with the exciting arrangement, and as in the first sequential scanning, as shown in fig. 3, every two adjacent scans, the leads connected with the exciting arrangement are spaced by a plurality of leads, preferably, the distance between the leads connected with the exciting arrangement in the two scans is equal to the distance between the leads connected with the exciting arrangement in the first sequential scanning. The scanning of the whole liquid crystal capacitive touch screen is completed by sequential scanning for a plurality of times and by selecting different wires connected to the comparison device.

It should be noted that, during the scanning process, the selection of the wires connected to the comparing device may be performed in the order of position, or may be performed at the same intervals as the wires connected to the exciting device. And the third, fourth and fifth conductors are numbered in a selected order, rather than in a positional order.

The invention is not limited to be applied to an embedded capacitive touch screen or a liquid crystal touch screen, and any touch screen with dense lead wires, namely a touch screen with dense induction electrodes, can be applied to the scanning method.

Claims

1. A scanning method of a capacitive touch screen, wherein the capacitive touch screen comprises a plurality of wires, is characterized in that: when the capacitive touch screen is scanned, one wire is selected to be connected to the exciting device every time, a plurality of wires are spaced between the wires connected to the exciting device in two adjacent scans, when the capacitive touch screen is scanned, one wire is selected to be connected to the exciting device to form rising edge excitation, meanwhile, in the current scan, the wire connected to the exciting device in the previous scan is grounded to form falling edge excitation, when the capacitive touch screen is scanned, the wires connected to the exciting device are selected in sequence from one side to the other side at intervals, and when the capacitive touch screen is scanned, the wires connected to the exciting device are selected in sequence through multiple intervals to complete the scanning of all the wires.

2. The method of scanning a capacitive touch screen according to claim 1, wherein: the interval between the leads connected to the excitation device is set according to the distance of one finger in the two adjacent scans.

3. The method of scanning a capacitive touch screen according to claim 1, wherein: any two adjacent scans are equally spaced between the wires connected to the excitation means.