Testing Method and Testing Device for Capacitive Touch Sensing Circuit

Abstract

The present application provides a test method and a test device for 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 dielectric layer is mounted on the capacitive touch sensing electrode. The method includes: when there is no external electric field, measuring, by the touch sensing unit, a reference charge required for the capacitive touch sensing electrode to reach a preset voltage; applying a preset external electric field to the capacitive touch sensing circuit by an external test circuit, and measuring, by the touch sensing unit, a test charge required for the capacitive touch sensing electrode to reach the preset voltage; calculating, according to the test charge, the reference charge, and the preset voltage, a to-be-tested inductive capacitance of the capacitive touch sensing circuit; measuring, in the same external electric field, a standard inductive capacitance of a preset capacitive touch sensing standard circuit; and calculating a comparison deviation value according to the to-be-tested inductive capacitance and the standard inductive capacitance to determine whether the capacitive touch sensing circuit passes the test.

Description

Technical Field

[0001] The present application relates to the technical field of capacitive sensing, and particularly relates to a test method and a test device for a capacitive touch sensing circuit. Background Art

[0002] Currently, in the fields of household appliances and industrial control, with the demand for appliance intelligence, more and more electrical products need to be configured with touch inputs. For the detection of capacitive touch sensing circuits in the production process, human body self-capacitance sensing is mostly used for detection. This method can only perform qualitative tests, with low detection accuracy, poor measurability repeatability, and long test time. Moreover, when an external passive metal conductor is used to simulate the human body's capacitance to the ground, affected by environmental changes such as humidity and temperature, the capacitance to the ground is also discrete, and quantitative testing cannot be performed. Summary of the Invention

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

[0004] In a first aspect, an embodiment of the present application provides a test method for 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 the sensing surface of the capacitive touch sensing electrode, and the touch sensing unit is connected to the capacitive touch sensing electrode. The method includes:

[0005] In the absence of an external electric field, the touch sensing unit measures the charge required for the capacitive touch sensing electrode to reach a preset voltage, which is used as a reference charge;

[0006] An external test circuit applies a preset external electric field to the capacitive touch sensing circuit, and the touch sensing unit measures the charge required for the capacitive touch sensing electrode to reach a preset voltage, which is used as a test charge;

[0007] According to the test charge, the reference charge, and the preset voltage, the to-be-tested sensing capacitance of the capacitive touch sensing circuit is calculated;

[0008] In the same external electric field, the standard sensing capacitance of a preset capacitive touch sensing standard circuit is measured;

[0009] According to the to-be-tested sensing capacitance and the standard sensing capacitance, a comparison deviation value is calculated, and according to the comparison deviation value, it is determined whether the capacitive touch sensing circuit passes the test.

[0010] In some embodiments, the specific calculation formula for calculating the to-be-tested sensing capacitance of the capacitive touch sensing circuit is:

[0011] ;

[0012] Wherein, ΔC t is the capacitance to be measured, Q1 is the test charge, Q0 is the reference charge, and U is the preset voltage.

[0013] In some embodiments, the specific formula for calculating the comparison deviation value is:

[0014] ;

[0015] Wherein, the ΔM C is the comparison deviation value, and the ΔC S is the standard inductive capacitance.

[0016] In some embodiments, when there is no external electric field, the charge required for the capacitive touch sensing electrode to reach the preset voltage is measured by the touch sensing unit as the reference charge, including:

[0017] When there is no external electric field, control the touch sensing unit to transmit charge to the capacitive touch sensing electrode. When the capacitive touch sensing electrode reaches the preset voltage, record the transmitted charge amount to obtain the reference charge.

[0018] In some embodiments, the test circuit includes: a test electrode and a measurement signal generation unit. The test electrode is connected to the measurement signal generation unit. 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.

[0019] In some embodiments, the electric field direction of the preset external electric field is perpendicular to the induction surface.

[0020] In a second aspect, an embodiment of the present application provides a test device. The test device includes a test unit and a test electrode. The test 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 test unit is connected to the touch sensing unit. The test device is used to execute the test method of the capacitive touch sensing circuit according to any one of the embodiments of the present application.

[0021] An embodiment of the present application provides a test method for 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 the sensing surface of the capacitive touch sensing electrode, and the touch sensing unit is connected to the capacitive touch sensing electrode. The method includes: 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; applying a preset external electric field to the capacitive touch sensing circuit through an external test circuit, and measuring, by the touch sensing unit, the charge required for the capacitive touch sensing electrode to reach the preset voltage as a test charge; calculating a to-be-tested inductive capacitance of the capacitive touch sensing circuit according to the test charge, the reference charge, and the preset voltage; measuring a standard inductive 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 inductive capacitance and the standard inductive capacitance, and determining whether the capacitive touch sensing circuit passes the test according to the comparison deviation value. Through the above method, due to the polarization effect of the external electric field on the dielectric layer, polarized charges are quantitatively applied to the dielectric layer. The to-be-tested inductive capacitance of the capacitive touch sensing circuit and the standard inductive capacitance of the capacitive touch sensing standard circuit are measured through the quantitative polarized charges, and then according to the comparison deviation value between the to-be-tested inductive capacitance and the standard inductive capacitance, it is determined whether the capacitive touch sensing circuit passes the test. In this way, it is possible to determine whether the capacitive touch sensing circuit passes the test under quantitative conditions, and it is also possible to replace manual detection to achieve test automation and speed up the detection speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0023] Figure 1 It is a schematic diagram of an artificial detection method provided by an embodiment of the present application;

[0024] Figure 2 It is a schematic diagram of a metal post detection method provided by an embodiment of the present application;

[0025] Figure 3 It is a schematic structural diagram of a test device provided by an embodiment of the present application;

[0026] Figure 4 It is a schematic flowchart of a test method for a capacitive touch sensing circuit provided by an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0028] The flowcharts shown in the accompanying drawings are only illustrative examples, and do not necessarily include all the contents and operations / steps, nor do they necessarily need to be executed in the described order. For example, some operations / steps can be decomposed, combined, or partially merged. Therefore, the actual execution order may change according to the actual situation.

[0029] It should also be understood that the terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. As used in the specification of this application and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an", and "the" are intended to include the plural forms.

[0030] It should be further understood that the term "and / or" used in the specification of this application and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0031] Please refer to Figure 1 , Figure 1 which is a schematic diagram of an artificial detection method provided by an embodiment of this application. As Figure 1 shown, for the detection of the capacitive touch sensing circuit in the production process, human body self-capacitance induction is mostly used for detection. This method can only perform qualitative testing, with low detection accuracy, poor measurability repeatability, and long testing time.

[0032] Please refer to Figure 2 , Figure 2 which is a schematic diagram of a metal post detection method provided by an embodiment of this application. As Figure 2 shown, by externally connecting a passive metal post to simulate the human body's capacitance to the ground, affected by environmental changes such as humidity and temperature, through this testing method, the capacitance to the ground is discrete and cannot be quantitatively tested.

[0033] Please refer to Figure 3 , Figure 3 which is a schematic structural diagram of a testing device provided by an embodiment of this application. As 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 mounted 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.

[0034] In some embodiments, the test electrode 12 is mounted 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.

[0035] In some embodiments, the electric field direction of the preset external electric field is perpendicular to the sensing surface.

[0036] To more clearly introduce the technical solution of the present application, the technical solution of the present application will also be introduced through specific embodiments below. It should be noted that this specific embodiment is used to expand the description of the technical solution of the present application, rather than limiting the present application.

[0037] Please refer to Figure 4 , Figure 4 which is a schematic flow chart of a test method for a capacitive touch sensing circuit 200 provided by an embodiment of the present application. As Figure 4 shown, the specific steps of the test method for the capacitive touch sensing circuit 200 include: S101 - S105.

[0038] S101. When there is no external electric field, measure the charge required for the capacitive touch sensing electrode to reach a preset voltage through the touch sensing unit, and use it as the reference charge.

[0039] Exemplarily, when no external electric field is applied, 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 as the "reference capacitance C0" for detecting capacitance changes. The capacitive touch sensing circuit 200 delivers charge to the capacitive touch sensing electrode 23 to make the voltage of the capacitive touch sensing electrode 23 reach 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.

[0040] S102. Apply a preset external electric field to the capacitive touch sensing circuit through an external test circuit, and measure the charge required for the capacitive touch sensing electrode to reach a preset voltage through the touch sensing unit, and use it as the test charge.

[0041] Exemplarily, an external electric field is applied through 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 polarization charges are generated on the sensing surface of the capacitive touch sensing electrode 23. At this time, the touch sensing unit 22 needs to provide an incremental charge ΔQ and deliver it to the capacitive touch sensing electrode 23. With a preset voltage value U and the total capacitance C of the capacitive touch sensing circuit 200 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.

[0042] S103. Calculate the sensing capacitance to be measured of the capacitive touch sensing circuit according to the test charge, reference charge, and preset voltage.

[0043] In some embodiments, the specific calculation formula for calculating the sensing capacitance to be measured of the capacitive touch sensing circuit 200 is:

[0044] ;

[0045] where, ΔC t is the sensing capacitance to be measured, Q1 is the test charge, Q1 = Q0 + ΔQ, Q0 is the reference charge, and U is the preset voltage.

[0046] S104. Measure the standard sensing capacitance of the preset capacitive touch sensing standard circuit in the same external electric field.

[0047] Exemplarily, the preset capacitive touch sensing standard circuit and the capacitive touch sensing circuit 200 to be tested have the same circuit structure. The preset capacitive touch sensing standard circuit is a circuit manually determined as a reference standard. The test process of the standard sensing capacitance is the same as that of the sensing capacitance to be measured, and will not be elaborated here.

[0048] S105. Calculate the comparison deviation value according to the sensing capacitance to be measured and the standard sensing capacitance, and determine whether the capacitive touch sensing circuit passes the test according to the comparison deviation value.

[0049] In some embodiments, the specific formula for calculating the comparison deviation value is:

[0050] ;

[0051] where, ΔM C is the comparison deviation value, ΔC S is the standard sensing capacitance.

[0052] Exemplarily, the standard sensing capacitance ΔC is obtained by using the preset capacitive touch sensing standard circuit under a fixed external electric field S , and the sensing capacitance to be tested ΔC of the capacitive touch sensing circuit 200 to be tested is measured under the same conditionst 。The polarization charges generated by the fixed external electric field in the dielectric layer 21 are constant, so the measured incremental capacitance ΔC can be quantified. ΔM C It can quantify the feedback of the capacitive touch sensing circuit 200 (including the installation position of the capacitive touch sensing electrode 23) on the influence of the external electric field, so as to quantitatively evaluate the overall quality of the capacitive touch sensing circuit 200 (including the installation position of the capacitive touch sensing electrode 23).

[0053] In some embodiments, when there is no external electric field, the charge required for the capacitive touch sensing electrode 23 to reach the preset voltage is measured by the touch sensing unit 22 as the reference charge, including: when there is no external electric field, controlling the touch sensing unit 22 to transmit charge to the capacitive touch sensing electrode 23, and when the capacitive touch sensing electrode 23 reaches the preset voltage, recording the transmitted charge amount to obtain the reference charge.

[0054] The influence of the above 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, greatly improve the detection accuracy, replace manual detection, realize test automation, reduce the production test cost and manual deviation, and has wide application value in industrial production.

[0055] As described above, the above is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present application can easily think of various equivalent modifications or replacements, and these modifications or replacements should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to 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 as claimed in claim 2, 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 electric field direction of the preset external electric field is perpendicular to the sensing surface.

6. 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. One end of the testing unit is used to connect the testing electrode, and the other end of the testing unit is used to connect the touch sensing unit. The testing electrode is installed on the second surface of the dielectric layer. The first surface of the dielectric layer of the capacitive touch sensing circuit is opposite to the second surface of the dielectric layer. The testing device is used to perform the testing method of the capacitive touch sensing circuit according to any one of claims 1 to 5.

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