CN102033673B - Capacitance test circuit and method for scanning line of capacitive touch screen and touch screen - Google Patents
Capacitance test circuit and method for scanning line of capacitive touch screen and touch screen Download PDFInfo
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- CN102033673B CN102033673B CN 201110000260 CN201110000260A CN102033673B CN 102033673 B CN102033673 B CN 102033673B CN 201110000260 CN201110000260 CN 201110000260 CN 201110000260 A CN201110000260 A CN 201110000260A CN 102033673 B CN102033673 B CN 102033673B
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Abstract
The invention relates to a capacitance test circuit and a capacitance test method for a scanning line of a capacitive touch screen and the touch screen. A capacitance to be tested is connected in parallel with an external capacitance and then is output by a comparator, so that the aim of testing the capacitance is fulfilled. In the capacitance test circuit and the capacitance test method for the scanning line of the capacitive touch screen and the touch screen, the defect of unavailable judgment of whether the touch screen is a non-defective product or not due to unavailable test of the capacitance in the prior art is overcome; moreover, in the test method, a test can be finished before the touch screen is molded and adjustment is performed in time, so that a defective product is transformed into a non-defective product, cost is saved and product yield is increased.
Description
Technical field
The present invention relates to a kind of capacitive touch screen sweep trace capacitance test method, refer in particular to this method with and corresponding touch-screen.
Background technology
At present, judge the whether qualified whether conducting of test scan line, impedance magnitude and the capacitance size of generally needing of capacitive touch screen, and in order to save testing cost, all before moulding, just finish various testing procedures as the step 1 of test touch screen.And in present stage, ITO only can test out its conducting and impedance on the touch-screen after etching, though can get rid of a part of defective products by the test of conducting and impedance before the touch-screen moulding flows in next processing step, but owing to method without any test scan line capacitance value, so cause and after the touch-screen moulding, to judge whether being specification product by the operation fluency of pointing.
So, the method of testing of capacitive touch screen sweep trace electric capacity always is the industry problem demanding prompt solution and since capacitance may directly cause the unusual of a lot of functions unusually, influence operability, if, just can judge whether touch-screen is qualified so test out capacitance on each bar sweep trace.And because the interference of external environment, capacitance on the touch-screen upper tracer is influenced by it also can, so the capacitance that detects at present all is the capacitances that comprise the outside noise influence, this influence must be controlled in certain scope just can not influence its operating performance, otherwise the just very possible cisco unity malfunction of touch-screen.As common singly referring to or two finger drawing linearity, sawtooth will appear if electric capacity overruns, and cause smoothness very poor, more will cause can't setting-out for severe patient.Detected touch-screen is if unacceptable product also can only just finally cause this result just because of the reason that does not have test scan line capacitance value as scrap so.
Therefore, we wish to provide a kind of new not only can the test scan line on electric capacity size, can save the method for testing of cost again.
Summary of the invention
The actual technical matters to be solved of the present invention is the method how a kind of testing capacitor formula touch-screen sweep trace capacitance size is provided.
In order to realize above-mentioned purpose of the present invention, the invention provides a kind of test circuit of capacitive touch screen sweep trace electric capacity, comprise testing capacitance and external tunable capacitor and two coupling capacitances on the sweep trace, the electric capacity of any sweep trace to be measured and external tunable capacitor are after parallel connection on the described touch-screen, the one end connects signal output, the other end through comparer relatively after output the result, wherein, described testing capacitance formation one circuit in parallel with one of them coupling capacitance, the described external capacitor circuit that forms again in parallel with another coupling capacitance, and then with described two circuit parallel connections after comparer back output result relatively.
Capacitive touch screen sweep trace capacitance test circuit of the present invention and method and touch-screen, thereby not only overcome tradition and can not can not judge whether touch-screen is the shortcoming of non-defective unit by testing capacitor, and this method of testing can be finished test before the touch-screen moulding, in time adjust the fraction defective that production technology reduces product, save cost, and improved the yield of product.
Description of drawings
Fig. 1 is the circuit connection diagram of capacitance touch screen sweep trace test of the present invention;
Fig. 2 is the method flow diagram of capacitance touch screen sweep trace test of the present invention.
Embodiment
The present invention is further illustrated below in conjunction with drawings and Examples.
Touch-screen of the present invention comprises a Petting Area, external capacitor Cadj and touch-control chip.Described Petting Area is used to provide the zone of touch, and user's finger can be operated thereon, and Petting Area is provided with some sweep traces, is connected respectively on the pin of touch-control chip correspondence; Described external capacitor Cadj is a kind of adjustable condenser of external circuits; Described touch-control chip is used to calculate the size of capacitance.Please refer to Fig. 1 described is the capacitor C x of any sweep trace on the touch-screen and the connection diagram of external tunable capacitor Cadj, the capacitor C x of any sweep trace to be measured and external tunable capacitor Cadj are after parallel connection on the touch-screen, the one end connects signal output, as driving source or signal generator; The other end through comparer 10 relatively after output the result.Wherein, described capacitor C x and coupling contain capacitor C 1 and are in parallel and form a circuit, and described external capacitor Cadj and coupling capacitance C2 are in parallel to form a circuit, and then with above-mentioned two circuit parallel connections after comparer 10 is relatively exported the result in the back.
Please refer to shown in Figure 2, in the capacitive touch screen sweep trace capacitance test method of the present invention, at first need to determine have any sweep trace to be measured to be in off-state on the touch-screen, sweep trace to be measured and described Touch Zone are disconnected, and keep other sweep trace to be connected with the respective pins of described touch-control chip this moment; Secondly, the capacitor C x of sweep trace to be measured is connected according to the connected mode of above-mentioned Fig. 1, it is in parallel with coupling capacitance C1 to be about to testing capacitance Cx, and an end that is actually C1 is connected other end ground connection with an input end of comparer 10; Again that external Cadj is in parallel with coupling capacitance C2, an end that is actually C2 is connected other end ground connection with another input end of comparer 10; Regulate external tunable capacitor Cadj then,, judge that promptly output valve whether in a threshold value, if in described threshold value, thinks that then the capacitance of this sweep trace to be measured can be accepted up to detecting comparer 10 output valves and other sweep trace coupling; If not in described threshold value, think that then the capacitance of this sweep trace to be measured can not be accepted.
Above-mentioned threshold value is meant a numerical value close with other sweep trace capacitance, and its concrete numerical value can rule of thumb be worth definite, and coupling capacitance C1 and C2 influence testing capacitance Cx and external capacitor Cadj respectively.And when the capacitance of above-mentioned sweep trace to be measured during not at this threshold value, the size that can regulate external capacitor Cadj up to output valve till within the described threshold value.So, just can draw deviation with other sweep trace by the size of regulating external capacitor Cadj, bring in for engineering, know the size of deviation, that just can attempt improvement by technology, thereby provides the foundation for follow-up improvement.
The method of testing of capacitive touch screen sweep trace of the present invention, in a single day just can test as long as form sweep trace on the touch-screen, thus after ITO is etched in glass, just be used for and can test, if so find defective products, can in time write down, adjust, thereby guarantee the quality of touch-screen; And the adjustment before the touch-screen moulding also can reduce the fraction defective of product, finally saved cost.
Claims (10)
1. the test circuit of a capacitive touch screen sweep trace electric capacity, comprise testing capacitance and external tunable capacitor and two coupling capacitances on the sweep trace, it is characterized in that, the electric capacity of any sweep trace to be measured and external tunable capacitor are after parallel connection on the described touch-screen, the one end connects signal output, the other end through comparer relatively after output the result, wherein, described testing capacitance formation one circuit in parallel with one of them coupling capacitance, the described external capacitor circuit that forms again in parallel with another coupling capacitance, and then with described two circuit parallel connections after comparer back output result relatively.
2. test circuit as claimed in claim 1 is characterized in that: an end of described coupling capacitance is connected other end ground connection with an input end of comparer.
3. test circuit as claimed in claim 1 is characterized in that: the input end after described two circuit parallel connections is a signal end.
4. test circuit as claimed in claim 1 is characterized in that: described coupling capacitance influences testing capacitance in parallel with it or external capacitor respectively.
5. method of testing that adopts the described capacitive touch screen sweep trace of claim 1 capacitance test circuit, wherein the capacitive touch screen sweep trace is connected respectively on the pin of touch-control chip correspondence, and its step is as follows:
At first, determine that sweep trace to be measured and described touch-control chip disconnect;
Secondly, regulate the size of external capacitor;
At last, whether the capacitance of detecting other sweep trace on output valve after the comparer output and touch-screen mates.
6. method of testing as claimed in claim 5 is characterized in that: whether the output valve after the output of described comparer is meant that with other sweep trace coupling output valve is whether in a preset threshold value.
7. method of testing as claimed in claim 6 is characterized in that: described output valve thinks that then the capacitance of sweep trace to be measured can be accepted if in described threshold value.
8. method of testing as claimed in claim 6 is characterized in that: if not in described threshold value, then regulate external capacitor and make its output valve till within the threshold value.
9. capacitive touch screen that adopts the test circuit of the described capacitive touch screen sweep trace of claim 1 electric capacity, it comprises Petting Area and touch-control chip and external capacitor, described Petting Area upper tracer is connected respectively on the respective pins of touch-control chip, it is characterized in that: described sweep trace to be measured and touch-control chip pin disconnect, and an end of described external capacitor is connected to the input end of touch-control chip, and the other end is connected on the sweep trace to be measured.
10. capacitive touch screen as claimed in claim 9 is characterized in that: described external capacitor is a kind of adjustable condenser of external circuits.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201110000260 CN102033673B (en) | 2011-01-04 | 2011-01-04 | Capacitance test circuit and method for scanning line of capacitive touch screen and touch screen |
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| Application Number | Priority Date | Filing Date | Title |
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| CN 201110000260 CN102033673B (en) | 2011-01-04 | 2011-01-04 | Capacitance test circuit and method for scanning line of capacitive touch screen and touch screen |
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| Publication Number | Publication Date |
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| CN102033673A CN102033673A (en) | 2011-04-27 |
| CN102033673B true CN102033673B (en) | 2013-07-31 |
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| CN 201110000260 Active CN102033673B (en) | 2011-01-04 | 2011-01-04 | Capacitance test circuit and method for scanning line of capacitive touch screen and touch screen |
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Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102364879A (en) * | 2011-06-23 | 2012-02-29 | 苏州瀚瑞微电子有限公司 | Circuit structure of capacitive touch button |
| CN102654543B (en) * | 2012-05-23 | 2014-07-30 | 东莞通华液晶有限公司 | Method for testing capacitive touch screens and testing equipment thereof |
| CN105224149B (en) * | 2014-06-06 | 2018-02-16 | 敦泰科技有限公司 | A kind of method for detecting capacitive touch screen |
| CN106526332B (en) * | 2016-10-25 | 2020-01-17 | 华南师范大学 | System and method for detecting capacitance on scanning line of capacitive touch screen |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2004040538A1 (en) * | 2002-10-28 | 2004-05-13 | Semtech Corporation | Data acquisition from capacitive touch pad |
| CN101796423A (en) * | 2007-05-08 | 2010-08-04 | 新思公司 | Production testing of a capacitive touch sensing device |
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2004040538A1 (en) * | 2002-10-28 | 2004-05-13 | Semtech Corporation | Data acquisition from capacitive touch pad |
| CN101796423A (en) * | 2007-05-08 | 2010-08-04 | 新思公司 | Production testing of a capacitive touch sensing device |
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