Test method and test device for capacitive touch sensing circuit

Abstract

The invention provides a test method and a test device for a capacitive touch sensing circuit, the capacitive touch sensing circuit comprises a dielectric layer, a touch sensing unit and a capacitive touch sensing electrode, the dielectric layer is mounted on the capacitive touch sensing electrode, and the method comprises the following steps: when no external electric field exists, the touch sensing unit is electrically connected with the dielectric layer; measuring a reference charge required by the capacitive touch sensing electrode to reach a preset voltage through the touch sensing unit; applying a preset external electric field to the capacitive touch sensing circuit through an external test circuit, and measuring a test charge required by the capacitive touch sensing electrode to reach a preset voltage through the touch sensing unit; according to the test charge, the reference charge and the preset voltage, calculating a to-be-tested induction capacitance of the capacitive touch induction circuit; in the same external electric field, standard induction capacitance of a preset capacitance touch control induction standard circuit is measured; and calculating a comparison deviation value according to the to-be-tested induction capacitor and the standard induction capacitor so as to judge whether the capacitive touch induction circuit passes the test or not.

Description

Technical Field

[0001] The present application relates to the field of capacitive sensing technology, and in particular to a testing method and a testing device for a capacitive touch sensing circuit. Background Art

[0002] At present, in the field of household appliances and industrial control, with the demand for intelligent appliances, more and more electrical products need to be equipped with touch input. For the detection of capacitive touch sensing circuits in the production process, the human body's own capacitance sensing is often used for detection. This method can only perform qualitative tests, with low detection accuracy, poor measurable repeatability, and long testing time. The external passive metal conductor simulates the capacitance of the human body to the ground. Affected by environmental changes such as humidity and temperature, the capacitance to the ground is also discrete and cannot be quantitatively tested. Summary of the invention

[0003] The present application provides a capacitive touch sensing circuit testing method and testing device, which are used to perform quantitative testing on the capacitive touch sensing circuit to improve detection accuracy and detection speed.

[0004] In a first aspect, an embodiment of the present application provides a method for testing a capacitive touch sensing circuit, wherein the capacitive touch sensing circuit comprises: a dielectric layer, a touch sensing unit and a capacitive touch sensing electrode, wherein a first surface of the dielectric layer is mounted on a sensing surface of the capacitive touch sensing electrode, and the touch sensing unit is connected to the capacitive touch sensing electrode, and the method comprises: When there is no external electric field, the touch sensing unit measures the charge required for the capacitive touch sensing electrode to reach a preset voltage as a reference charge; Applying a preset external electric field to the capacitive touch sensing circuit through an external test circuit, and measuring the charge required for the capacitive touch sensing electrode to reach a preset voltage through the touch sensing unit as a test charge; Calculating the sensing capacitance to be measured of the capacitive touch sensing circuit according to the test charge, the reference charge and the preset voltage; In the same external electric field, measuring the standard sensing capacitance of a preset capacitive touch sensing standard circuit; A comparison deviation value is calculated according to the sensing capacitor to be tested and the standard sensing capacitor, and whether the capacitive touch sensing circuit passes the test is determined according to the comparison deviation value.

[0005] In some embodiments, a specific calculation formula for calculating the measured sensing capacitance of the capacitive touch sensing circuit is: ; Where, ΔC t is the inductive capacitor to be tested, Q1 is the test charge, Q0 is the reference charge, and U is the preset voltage.

[0006] In some embodiments, the specific formula for calculating the contrast deviation value is: ; Among them, the ΔM C is the contrast deviation value, the ΔC S is the standard inductive capacitance.

[0007] In some embodiments, when there is no external electric field, measuring, by the touch sensing unit, the charge required for the capacitive touch sensing electrode to reach a preset voltage as a reference charge, includes: When there is no external electric field, the touch sensing unit is controlled to transfer charges to the capacitive touch sensing electrode, and when the capacitive touch sensing electrode reaches a preset voltage, the amount of the transferred charge is recorded to obtain the reference charge.

[0008] In some embodiments, the test circuit includes: a test electrode and a measurement signal generating unit, the test electrode and the measurement signal generating unit are connected, the test electrode is installed on the second surface of the dielectric layer, and the first surface of the dielectric layer is opposite to the second surface of the dielectric layer.

[0009] In some embodiments, the electric field direction of the preset external electric field is perpendicular to the sensing surface.

[0010] In a second aspect, an embodiment of the present application provides a testing device, which includes a testing unit and a testing electrode. The testing device is used to measure a capacitive touch sensing circuit, and the capacitive touch sensing circuit includes: a dielectric layer, a touch sensing unit and a capacitive touch sensing electrode. The testing unit is connected to the touch sensing unit, and the testing device is used to execute a testing method for a capacitive touch sensing circuit as described in any one of the embodiments of the present application.

[0011] The embodiment of the present application provides a method for testing a capacitive touch sensing circuit. The capacitive touch sensing circuit includes: a dielectric layer, a touch sensing unit and a capacitive touch sensing electrode. The first surface of the dielectric layer is mounted on a sensing surface of the capacitive touch sensing electrode. The touch sensing unit is connected to the capacitive touch sensing electrode. The method includes: when there is no external electric field, measuring the charge required for the capacitive touch sensing electrode to reach a preset voltage through the touch sensing unit as a reference charge; applying a preset external electric field to the capacitive touch sensing circuit through an external test circuit, measuring the charge required for the capacitive touch sensing electrode to reach a preset voltage through the touch sensing unit as a test charge; calculating a to-be-tested sensing capacitance of the capacitive touch sensing circuit according to the test charge, the reference charge and the preset voltage; measuring a standard sensing capacitance of a preset capacitive touch sensing standard circuit in the same external electric field; calculating a comparison deviation value according to the to-be-tested sensing capacitance and the standard sensing capacitance, and judging whether the capacitive touch sensing circuit passes the test according to the comparison deviation value. Through the above method, the polarization effect of the external electric field on the dielectric layer is used to quantitatively apply polarization charges to the dielectric layer, and the measured sensing capacitance of the capacitive touch sensing circuit and the standard sensing capacitance of the capacitive touch sensing standard circuit are calculated through the quantitative polarization charges. Then, according to the comparison deviation value between the measured sensing capacitance and the standard sensing capacitance, it is judged whether the capacitive touch sensing circuit passes the test. In this way, it is possible to judge whether the capacitive touch sensing circuit passes the test quantitatively, and it is also possible to replace manual detection, realize test automation, and speed up the detection speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying any creative work.

[0013] Figure 1 A schematic diagram of a manual detection method provided in an embodiment of the present application; Figure 2 A schematic diagram of a metal column detection method provided in an embodiment of the present application; Figure 3 A schematic diagram of the structure of a testing device provided in an embodiment of the present application; Figure 4 A schematic flowchart of a method for testing a capacitive touch sensing circuit provided in an embodiment of the present application. DETAILED DESCRIPTION

[0014] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0015] The flowcharts shown in the accompanying drawings are only examples and do not necessarily include all the contents and operations / steps, nor must they be executed in the order described. For example, some operations / steps may also be decomposed, combined or partially merged, so the actual execution order may change according to actual conditions.

[0016] It should also be understood that the terms used in this application specification are only for the purpose of describing specific embodiments and are not intended to limit the application. As used in this application specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0017] It should be further understood that the term “and / or” used in the specification and appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0018] See also Figure 1 , Figure 1 FIG. 1 is a schematic diagram of a manual detection method provided in an embodiment of the present application. Figure 1 As shown, for the detection of capacitive touch sensing circuits in the production process, the human body's own capacitance sensing is mostly used for detection. This method can only perform qualitative testing, has low detection accuracy, poor measurable repeatability, and long testing time.

[0019] See also Figure 2 , Figure 2 Schematic diagram of a metal column detection method provided in an embodiment of the present application. Figure 2 As shown, the capacitance between the human body and the ground is simulated by an external passive metal column, which is affected by environmental changes such as humidity and temperature. Through this test method, the capacitance to the ground is discrete and cannot be quantified.

[0020] See also Figure 3 , Figure 3 is a schematic diagram of the structure of a test device provided in an embodiment of the present application. Figure 3As shown. The test device 100 includes: a test unit 11 and a test electrode 12. The test unit 11 is connected to the test electrode 12, and the test electrode 12 is used to generate a preset external electric field. The capacitive touch sensing circuit 200 includes: a dielectric layer 21, a touch sensing unit 22 and a capacitive touch sensing electrode 23. The test unit 11 is connected to the touch sensing unit 22. The first surface of the dielectric layer 21 is installed on the sensing surface of the capacitive touch sensing electrode 23, and the touch sensing unit 22 is connected to the capacitive touch sensing electrode 23.

[0021] In some embodiments, the test electrode 12 is installed on the second surface of the dielectric layer 21 , and the first surface of the dielectric layer 21 is opposite to the second surface of the dielectric layer 21 .

[0022] In some embodiments, the electric field direction of the preset external electric field is perpendicular to the sensing surface.

[0023] In order to more clearly introduce the technical solution of the present application, the technical solution of the present application will be introduced through specific embodiments below. It should be noted that the specific embodiments are used to expand the technical solution of the present application, but are not intended to limit the present application.

[0024] See also Figure 4 , Figure 4 FIG. 2 is a schematic flow chart of a method for testing a capacitive touch sensing circuit 200 provided in an embodiment of the present application. Figure 4 As shown, the specific steps of the test method of the capacitive touch sensing circuit 200 include: S101-S105.

[0025] S101 . When there is no external electric field, the charge required for the capacitive touch sensing electrode to reach a preset voltage is measured by a touch sensing unit as a reference charge.

[0026] Exemplarily, when no external electric field is added, the native capacitance of the capacitive touch sensing circuit 200 includes: parasitic capacitance, sensor capacitance and ground return capacitance. The native capacitance is measured during calibration and is used to detect the "reference capacitance C0" of the capacitance change. The capacitive touch sensing circuit 200 delivers charge to the capacitive touch sensing electrode 23 so that the voltage of the capacitive touch sensing electrode 23 reaches the preset voltage U. By measuring the delivered charge amount Q0, the capacitance of the reference capacitance C0 can be calculated. The specific calculation formula is: C0=Q0 / U.

[0027] S102: applying a preset external electric field to the capacitive touch sensing circuit through an external test circuit, and measuring the charge required for the capacitive touch sensing electrode to reach a preset voltage through the touch sensing unit as a test charge.

[0028] Exemplarily, an external electric field is applied by an external test circuit, and the dielectric layer 21 of the capacitive touch sensing circuit 200 is polarized in the external electric field, so that the sensing surface of the capacitive touch sensing electrode 23 generates polarized charges. At this time, the touch sensing unit 22 needs to provide an incremental charge ΔQ to be transmitted to the capacitive touch sensing electrode 23, and the total capacitance C of the capacitive touch sensing circuit 200 is set to a preset voltage value U. Z =(Q0+ΔQ) / U, the calculation formula for the incremental capacitance generated by the external electric field is: ΔC=ΔQ / U, where ΔC is the incremental capacitance.

[0029] S103: Calculate the sensing capacitance to be tested of the capacitive touch sensing circuit according to the test charge, the reference charge and the preset voltage.

[0030] In some embodiments, the specific calculation formula for calculating the measured sensing capacitance of the capacitive touch sensing circuit 200 is: ; Where, ΔC t is the inductive capacitor to be tested, Q1 is the test charge, Q1=Q0+ΔQ, Q0 is the reference charge, and U is the preset voltage.

[0031] S104 . In the same external electric field, measure a standard sensing capacitance of a preset capacitive touch sensing standard circuit.

[0032] Exemplarily, the circuit structure of the preset capacitive touch sensing standard circuit is the same as that of the capacitive touch sensing circuit 200 to be tested, and the preset capacitive touch sensing standard circuit is a circuit manually identified as a reference standard. The test process of the standard sensing capacitor is the same as that of the sensing capacitor to be tested, which will not be repeated here.

[0033] S105 , calculating a comparison deviation value according to the sensing capacitor to be tested and the standard sensing capacitor, and judging whether the capacitive touch sensing circuit passes the test according to the comparison deviation value.

[0034] In some embodiments, the specific formula for calculating the contrast deviation value is: ; Among them, ΔM C is the comparison deviation value, ΔC S is the standard sensing capacitor.

[0035] Exemplarily, a preset capacitive touch sensing standard circuit is used to obtain a standard sensing capacitance ΔC under a fixed external electric field. S , the capacitive touch sensing circuit 200 to be tested is measured under the same conditions to obtain the sensing capacitance ΔC to be tested. tThe polarization charge generated by the fixed external electric field in the dielectric layer 21 is constant, so the measured incremental capacitance ΔC can be quantified. ΔM C The feedback of the capacitive touch sensing circuit 200 (including the installation position of the capacitive touch sensing electrode 23 ) to the external electric field can be quantified, thereby quantitatively evaluating the overall quality of the capacitive touch sensing circuit 200 (including the installation position of the capacitive touch sensing electrode 23 ).

[0036] In some embodiments, when there is no external electric field, the charge required for the capacitive touch sensing electrode 23 to reach a preset voltage is measured by the touch sensing unit 22 as a reference charge, including: when there is no external electric field, controlling the touch sensing unit 22 to transfer charge to the capacitive touch sensing electrode 23, and when the capacitive touch sensing electrode 23 reaches the preset voltage, recording the amount of charge that has been transferred to obtain the reference charge.

[0037] The impact of the above-mentioned test method on the capacitive touch sensing circuit 200 is consistent with the human body model. The stable programmable signal generates a stable external electric field, which can replace the human body model to realize quantitative testing of the touch sensing circuit, which can greatly improve the detection accuracy, replace manual detection, realize test automation, reduce the cost of production testing and manual deviation, and has wide application value in industrial production.

[0038] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present application, and these modifications or replacements should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A method for testing a capacitive touch sensing circuit, characterized in that: The capacitive touch sensing circuit comprises: a dielectric layer, a touch sensing unit and a capacitive touch sensing electrode, the first surface of the dielectric layer is mounted on the sensing surface of the capacitive touch sensing electrode, the touch sensing unit is connected to the capacitive touch sensing electrode, and the method comprises: When there is no external electric field, the touch sensing unit measures the charge required for the capacitive touch sensing electrode to reach a preset voltage as a reference charge; Applying a preset external electric field to the capacitive touch sensing circuit through an external test circuit, and measuring the charge required for the capacitive touch sensing electrode to reach a preset voltage through the touch sensing unit as a test charge; Calculating the sensing capacitance to be measured of the capacitive touch sensing circuit according to the test charge, the reference charge and the preset voltage; In the same external electric field, measuring the standard sensing capacitance of a preset capacitive touch sensing standard circuit; A comparison deviation value is calculated according to the sensing capacitor to be tested and the standard sensing capacitor, and whether the capacitive touch sensing circuit passes the test is determined according to the comparison deviation value.

2. The method for testing a capacitive touch sensing circuit according to claim 1, wherein: The specific calculation formula for calculating the measured sensing capacitance of the capacitive touch sensing circuit is: ； Where, ΔC t is the inductive capacitor to be tested, Q1 is the test charge, Q0 is the reference charge, and U is the preset voltage.

3. The method for testing a capacitive touch sensing circuit according to claim 1, wherein: The specific formula for calculating the contrast deviation value is: ； Among them, the ΔM C is the contrast deviation value, the ΔC S is the standard inductive capacitance.

4. The method for testing a capacitive touch sensing circuit according to claim 1, wherein: The method of measuring the charge required for the capacitive touch sensing electrode to reach a preset voltage by the touch sensing unit when there is no external electric field, as a reference charge, includes: When there is no external electric field, the touch sensing unit is controlled to transfer charges to the capacitive touch sensing electrode, and when the capacitive touch sensing electrode reaches a preset voltage, the amount of the transferred charge is recorded to obtain the reference charge.

5. The method for testing a capacitive touch sensing circuit according to claim 1, wherein: The test circuit comprises: a test electrode and a measurement signal generating unit, the test electrode and the measurement signal generating unit are connected, the test electrode is installed on the second surface of the dielectric layer, and the first surface of the dielectric layer is opposite to the second surface of the dielectric layer.

6. The method for testing a capacitive touch sensing circuit according to claim 1, wherein: The electric field direction of the preset external electric field is perpendicular to the sensing surface.

7. A testing device, characterized in that: The testing device includes a testing unit and a testing electrode. The testing device is used to measure a capacitive touch sensing circuit. The capacitive touch sensing circuit includes: a dielectric layer, a touch sensing unit and a capacitive touch sensing electrode. The testing unit is connected to the touch sensing unit. The testing device is used to execute the testing method of the capacitive touch sensing circuit according to any one of claims 1 to 6.

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