CN102981059A

CN102981059A - Method for detecting defects of capacitive touch screen device

Info

Publication number: CN102981059A
Application number: CN2012103126661A
Authority: CN
Inventors: 张晋芳; 刘宏辉
Original assignee: BEIJING JICHUANG NORTHERN TECHNOLOGY CO LTD
Current assignee: Chipone Technology Beijing Co Ltd
Priority date: 2012-08-29
Filing date: 2012-08-29
Publication date: 2013-03-20
Anticipated expiration: 2032-08-29
Also published as: CN102981059B

Abstract

The invention relates to a method for detecting defects of a capacitive touch screen device. The device comprises a capacitive screen and a capacitive screen control chip. The detecting method includes sequentially driving all drive lines, measuring a mutual capacitive value between each drive line and a sense line as a standard when driving each drive line, changing the number of the drive lines driven at the same time, sequentially driving all the drive lines, measuring the mutual capacitive value between the drive lines and the sense line when driving two driving lines every time, and judging whether the defects exist according to difference between measured values of two times.

Description

A kind of capacitive touch screen architecture defect inspection method

Technical field

The present invention relates to a kind of capacitive touch screen device defect detection method, especially projecting type capacitor formula touch-screen sweep trace capacitance determining method.

Background technology

Touch-screen is because the advantages such as it is sturdy and durable, reaction velocity fast, saving space have obtained increasing application in various electronic device field.The projection-type capacitive touch screen product is becoming the mainstream product in the market at present.Its scanning theory as shown in Figure 1, make the overlapping electrod-array of transverse and longitudinal at glass baseplate surface with ITO (indium tin oxide), horizontal and vertical ITO electrode crossing place forms several Inductance and Capacitance, also be the two poles of the earth that two arrays of electrodes consists of respectively electric capacity, when occuring to touch, touch place adjacent electrode coupling situation changes, thereby the mutual capacitance value changes, by the change of scan capture to capacitance, namely obtain touch location.The touch-screen that consists of take 4 lines, 4 alignments is as example, the electrode of line and alignment; Consist of respectively the two poles of the earth of Inductance and Capacitance, when the position of pixel 103 correspondences on the finger touch screen, near two electrode couplings the pixel 103 change, cause the variation of Inductance and Capacitance 105 values, 102 pairs of lines of driving circuit, also be that drive wire Drive Iine100 timesharing applies the driving signal successively, to alignment, also be that sense wire Sense Iine104 carries out sensing by column, sensing signal obtains the position coordinates of touch point by operational amplifier 106 and output by the variation that detects corresponding capacitance.

Need before the touch-screen formed product its electrical specification such as capacitance are tested, to guarantee product yield.May there be defective in capacitance plate device and capacitance plate control chip and cause the capacitance detecting value constant, and no matter no touch is namely arranged, and corresponding capacitance is fixed value or changes not obvious.But only can test its conducting and impedance after the present stage touch-screen ITO etching, and can't test sweep trace electric capacity.Therefore can only utilize mechanical arm simulation finger the mode of operation that actual persons is simulated in action such as to rule, get ready at product, reading out data and processing then, whether the judgement product is qualified.This method efficient is low and be subjected to external interference easily and produce error.

Also having a kind of measuring technology is mode by external capacitor, whether relatively output after the row operation of going forward side by side in parallel is processed respectively with coupling capacitance with sweep trace testing capacitance, an external tunable capacitor can be accepted by the scanning capacitance value of relatively judging of analysis result and preset threshold value.The method has increased extra cost and extendability shortcoming.

The application namely proposes a kind of capacitance touch screen defect inspection method efficient, that easily expand, and sweep trace electric capacity is detected.

Summary of the invention

Purpose of the present invention namely provides a kind of capacitive touch screen architecture defect inspection method and adopts the capacitive touch screen architecture of the method in order to overcome the deficiencies in the prior art, can detect the capacitance profile of Projected capacitive touch screen, thereby further detect the touch-screen yield.

In the technical scheme of the present invention, drive successively first all drive wire Drive Line, drive wire of each driving, measure mutual capacitance value between every drive wire and the sense wire as benchmark, change again the drive wire radical that drives simultaneously, drive successively all drive wires, such as each driving i root drive wire, again measure the mutual capacitance value between drive wire and the sense wire, twice measurement result compared to judge whether that defectiveness exists, wherein i is the natural number less than the drive wire sum.

Capacitance touch screen is because the opening circuit of various factors such as adjacent electrode, short circuit etc., can cause Inductance and Capacitance to have defective, thereby cause the capacitance detecting value can't correctly detect actual capacitance value, when changing such as capacitance, the Detection capacitance value is constant or almost constant, perhaps improper numerical value appears in detected value, as much larger than or much smaller than normal mutual capacitance value variation range, and twice measured value difference of qualified capacitance plate is controlled in the zone of reasonableness usually.Compare with the threshold value of presetting by the deviation with measurement result, can judge whether capacitance plate exists defective.

With respect to prior art, but the method setting program that the present invention proposes automatically control, have and measure accurately the advantages such as efficient height, favorable expandability.

Description of drawings

Fig. 1 is the signal of capacitance touch screen drive principle.

Fig. 2 is that twice measured value difference tabulated before and after the capacitance plate of 6*6 changed the number of drive lines that drives simultaneously.

Embodiment

The present invention is described in detail below in conjunction with specific embodiment.

Take the capacitance plate of 6*6 as example, Tx among Fig. 2, Rx are the pins after the circuit chip encapsulation, and Tx is drive end, and Rx is sense terminals.For the mutual capacitance touchscreens of a N*M, N transmitting terminal Tx need to be arranged, link to each other with alignment (being sense wire) with the line (being drive wire) of electrode matrix respectively with M receiving end Rx.Detection method of the present invention drives a drive wire at first at every turn, drives successively T1-T6, measures the mutual capacitance value between every drive wire Tx and the sense wire Ry, obtain mutual capacitance value matrix C[x, y], and with it as benchmark, then, drive simultaneously 2 drive wires, according to T6﹠amp; T1, T1﹠amp; T2 ..., T5﹠amp; The order of T6 drives all drive wires successively, obtains new measured value Matrix C ' [x, y], and wherein C ' xy (1＜x≤6) is for driving simultaneously x-1, x row drive wire Tx-1, Tx, and the mutual capacitance measured value that scanning obtains to y row sense wire Ry, C ' _1yFor driving simultaneously the 6th, the 1st row drive wire T6﹠amp; T1, the mutual capacitance measured value that scanning obtains to sense wire Ry.Calculated difference matrix Δ C[x, y]=C[x, y]-C ' [x, y], twice measured value difference of qualified capacitance plate is controlled in the zone of reasonableness usually, such as Thr1＜Δ Cxy＜Thr2, Thr1, Thr2 are threshold value, and its concrete numerical value is determined by practical experience and data processing method.In the test practice, can test short run touch-screen product first, measure difference DELTA Cxy and be considered as continuous random variable, its Normal Distribution is analyzed distribution curve, determines choosing of threshold value according to fiducial interval.If the capacitance measurement difference not in the threshold value scope, thinks then that corresponding capacitance can not accept, this deviation and other sweep trace deviations are compared, can provide the basis for subsequent technique improves.

In the method that the present invention proposes, the drive wire number that drives simultaneously is not limited to 2, for example when driving 3 drive wires simultaneously, by measuring mutual capacitance measured value Matrix C ' [x, y], wherein C ' _1yFor driving simultaneously the drive wire of the 6th, the 1st, the 2nd row, the mutual capacitance measured value that scanning obtains to y row sense wire; C ' _6yFor driving simultaneously the 5th, the 6th, the 1st row drive wire, the mutual capacitance measured value that scanning obtains to y row sense wire; C ' xy (1＜x＜6) is for driving simultaneously x-1, x, x+1 row drive wire Tx-1, Tx, Tx+1, and the measured value that scanning obtains to y row sense wire Ry.

In the method that the present invention proposes, the measurement that matrix is measured in mutual capacitance is not limited to 2 times, can measure n time in the practice, measures matrix to n time and carries out analysis-by-synthesis, thereby improve test accuracy.

This method can be applicable to existing capacitive touch screen architecture, it comprises capacitance touch screen, capacitance touch screen control circuit and corresponding connecting circuit, control circuit comprises driving circuit and testing circuit, the driving voltage of the configurable different sizes of driving circuit, the capacitance plate control circuit can be independent chip, also can be integrated with the MCU of other electronic equipments, the quantity of capacitance plate control chip is not limited to 1, can expand according to demand, such as disposing a plurality of chips realization expansions for middle size or large-sized capacitance plate, to adapt to different demands.

Although take the capacitance plate of 6*6 as example, be not limited to the array of 6*6 in the present embodiment, the capacitance plate of shape such as N*M (M, N is natural number) form all can be with reference to the present embodiment examinations.The above only is preferred embodiment of the present invention, not in order to limiting the present invention, all any modifications of making within the spirit and principles in the present invention, is equal to and replaces and improvement etc., all should be included within protection scope of the present invention.

Claims

1. the method for a capacitive touch screen architecture defects detection, described device comprises capacitance plate, the capacitance plate control chip, be provided with drive wire Drive Line and sense wire Sense Line that many intersections are placed on the described capacitance plate, it is characterized in that, each row drive wire that drives drives all drive wires successively first, obtain the mutual capacitance value and measure matrix, drive successively all drive wires in the mode that drives simultaneously the i row drive wire again, obtain new mutual capacitance value and measure matrix, i is the natural number less than the drive wire line number, judges according to the difference situation of change of twice measurement result whether defectiveness exists corresponding capacitance.

2. the method for claim 1, for a capacitance touch screen that is provided with N row drive wire and M row sense wire,

At first the mode with each driving one row drive wire drives all drive wires successively, obtains the mutual capacitance value and measures Matrix C [x, y], and wherein Cxy is for driving the x row drive wire, the measured value that scanning obtains to y row sense wire;

Again drive simultaneously 2 row drive wires, drive successively all drive wires, obtain the mutual capacitance value and measure Matrix C ' [x, y], wherein (1＜x≤N) is for driving simultaneously x-1, x row drive wire, and y row sense wire is scanned the measured value that obtains, C ' for C ' xy _1yFor driving simultaneously N, the 1st row drive wire, the measured value that scanning obtains to y row sense wire;

Calculated difference matrix Δ C[x, y]=C[x, y]-C ' [x, y], twice measured value distribution of the difference of qualified capacitance plate is in a zone of reasonableness, and such as Thr1＜Δ Cxy＜Thr2, Thr1 and Thr2 are default threshold value.

3. method as claimed in claim 1 or 2, it is characterized in that: the measurement of described mutual capacitance value two-dimensional matrix can be n time, n＞2.

4. method as claimed in claim 1 or 2, it is characterized in that: described defective is the change that the Detection capacitance value can't correctly detect capacitance.

5. method as claimed in claim 1 or 2, it is characterized in that: described capacitance plate control chip comprises driving circuit and the testing circuit of configurable driving voltage, and described driving circuit has adjustable driving voltage.

6. method as claimed in claim 1 or 2, it is characterized in that: the number of described capacitance plate control chip can be more than 1, to adapt to the demand of different size capacitance plate.

7. method as claimed in claim 1 or 2, it is characterized in that: described capacitance plate control chip can also integrate with MCU.