Detection device

Abstract

The present application provides a detection device capable of suppressing a reduction in detection accuracy. The detection device is provided with: a detection region in which a plurality of electrodes are provided; a front surface cover made of a non-conductive material having hygroscopicity and covering the detection region; and a detection unit that detects an object to be detected approaching the detection region with the front surface cover interposed therebetween. The detection unit acquires a correction coefficient for correcting a signal value acquired when the object is detected on the basis of the correspondence between the signal value acquired when the non-detection operation of the object is not detected and the moisture content of the front cover.

Description

Technical Field

[0001] This invention relates to a detection device. Background Technology

[0002] In recent years, a detection device known as a so-called touch panel has been developed that can detect objects approaching from the outside. As the front surface cover of such a touch panel, it has been disclosed that it is made of materials derived from nature, such as wood, natural fibers, natural leather, or natural stone, or synthetic fibers, synthetic leather, artificial stone, etc., which imitate the appearance and feel of nature (for example, see Patent Document 1).

[0003] Patent Document 1: International Publication No. 2019 / 082399

[0004] In so-called electrostatic capacitive touch panels, when a front surface cover made of a hygroscopic, non-conductive material is placed on the front surface of the touch panel, the dielectric constant of the front surface cover may change due to changes in humidity, potentially reducing detection accuracy. Summary of the Invention

[0005] The purpose of this invention is to provide a detection device that can suppress the reduction of detection accuracy.

[0006] One aspect of the present invention relates to a detection device comprising: a detection area having a plurality of electrodes; a front surface cover made of a hygroscopic, non-conductive material and covering the detection area; and a detection unit for detecting a subject near the detection area via the front surface cover, wherein the detection unit acquires a correction coefficient for correcting the signal value acquired when the subject is detected, based on a correspondence between a signal value acquired when the subject is not detected during a non-detection action and the moisture content of the front surface cover. Attached Figure Description

[0007] Figure 1 This is a top view showing a simplified configuration of the detection device according to Embodiment 1.

[0008] Figure 2 This is a schematic diagram showing a simplified cross-sectional configuration of the sensor section of the detection device according to Embodiment 1.

[0009] Figure 3 This is a block diagram showing an example of the configuration of the detection unit of the detection device according to Embodiment 1.

[0010] Figure 4A It is a schematic diagram showing the relationship between the position of the object being detected in the space of the detection area and the position of each electrode.

[0011] Figure 4BThis is a schematic diagram showing the spatial coordinates of the object being detected in the space of the detection area.

[0012] Figure 5 This is a diagram showing an example of the connection configuration between the sensor section and the detection section of the detection device according to Embodiment 1.

[0013] Figure 6 This is a flowchart illustrating an example of the specific operations and processes in the detection device according to Embodiment 1.

[0014] Figure 7 This is a sub-flowchart illustrating an example of the correction coefficient setting process in the detection apparatus according to Embodiment 1.

[0015] Figure 8 This is a conceptual diagram illustrating the calibration coefficient setting operation of the detection device involved in Embodiment 1.

[0016] Figure 9 This is a schematic diagram illustrating an example of the correspondence between the signal value acquired during the correction coefficient setting operation and the correction coefficient.

[0017] Figure 10 This is a sub-flowchart illustrating an example of the correction coefficient setting process involved in a variation of Embodiment 1.

[0018] Figure 11A This is a conceptual diagram illustrating the correction coefficient setting operation involved in a variation of Implementation 1.

[0019] Figure 11B This is a conceptual diagram illustrating the correction coefficient setting operation involved in a variation of Implementation 1.

[0020] Figure 12 This is a top view showing a first example of the electrode configuration in the sensor section of the detection device according to Embodiment 2.

[0021] Figure 13 This is a schematic diagram showing a first example of a simplified cross-sectional configuration of the sensor section of the detection device according to Embodiment 2.

[0022] Figure 14 This is a top view showing a second example of the electrode configuration in the sensor section of the detection device according to Embodiment 2.

[0023] Figure 15 This is a schematic diagram showing a second example of a simplified cross-sectional configuration of the sensor section of the detection device according to Embodiment 2.

[0024] Figure 16 This is a sub-flowchart illustrating an example of the correction coefficient setting process in the detection device according to Embodiment 2.

[0025] Figure 17 This is a conceptual diagram illustrating the calibration coefficient setting operation of the detection device involved in Embodiment 2. Detailed Implementation

[0026] Referring to the accompanying drawings, the embodiments (implementations) for carrying out the present invention will be described in detail. It should be noted that the present invention is not limited to the contents described in the following embodiments. Furthermore, the constituent elements described below include elements readily conceived by those skilled in the art, as well as substantially the same elements. Moreover, the constituent elements described below can be appropriately combined. In addition, the disclosed examples are merely illustrative, and appropriate modifications that maintain the spirit of the invention and are readily conceived by those skilled in the art are naturally included within the scope of the present invention. Furthermore, to make the description clearer, the width, thickness, shape, etc., of various parts in the drawings are sometimes schematically shown compared to the actual aspects, but are ultimately just examples and do not limit the interpretation of the present invention. Furthermore, in this specification and the accompanying drawings, the same reference numerals are used for elements that are the same as those described in the previously shown drawings, and detailed descriptions are sometimes appropriately omitted.

[0027] (Implementation Method 1)

[0028] Figure 1 This is a top view showing a simplified configuration of the detection device according to Embodiment 1. Figure 1 As shown, the detection device 1 includes a sensor unit 10 and a detection unit 20.

[0029] The sensor unit 10 includes a sensor substrate 11, a plurality of electrodes 12 disposed in a detection area AA of the sensor substrate 11, and wiring 13 extending from each of the plurality of electrodes 12. The detection unit 20 includes a control substrate 21, a detection circuit 22, a processing circuit 23, a power supply circuit 24, and an interface circuit 25.

[0030] The detection area AA of the sensor substrate 11 is a region in which a plurality of electrodes 12 are arranged in a matrix in the Dx direction (first direction) and the Dy direction (second direction). The sensor substrate 11 is, for example, a rigid substrate or a flexible printed circuit board (FPC).

[0031] In this disclosure, the Dx direction and the Dy direction are orthogonal in the detection area AA of the sensor substrate 11. Furthermore, in this disclosure, the direction orthogonal to the Dx and Dy directions is designated as the Dz direction (third direction).

[0032] exist Figure 1The example shown illustrates a configuration of 5 × 4 (= 20) electrodes 12 arranged with 5 electrodes 12 in the Dx direction and 4 electrodes 12 arranged in the Dy direction, but the number of electrodes 12 arranged in the detection area AA of the sensor substrate 11 is not limited to this.

[0033] The control board 21 is electrically connected to the sensor board 11 via the wiring board 31. The wiring board 31 is, for example, a flexible printed circuit board. Each electrode 12 of the sensor unit 10 is connected to the detection circuit 22 of the detection unit 20 via the wiring board 31.

[0034] The control substrate 21 is provided with a detection circuit 22, a processing circuit 23, a power supply circuit 24, and an interface circuit 25. The control substrate 21 is, for example, a rigid substrate.

[0035] The detection circuit 22 generates a detection value for each electrode 12 based on the detection signals output from each electrode 12 from the sensor substrate 11. The detection circuit 22 is, for example, an analog front end (AFE) IC.

[0036] Based on the detection values ​​of each electrode 12 output from the detection circuit 22, the processing circuit 23 generates spatial coordinates representing the location of the detected object (e.g., an operator's finger) in the detection area AA. The processing circuit 23 may be, for example, a PLD (Programmable Logic Device) such as an FPGA (Field Programmable Gate Array), or a MCU (Micro Control Unit).

[0037] The power supply circuit 24 is a circuit that supplies power to the detection circuit 22 and the processing circuit 23.

[0038] The interface circuit 25, for example, is a USB controller IC, which is a circuit that controls the communication between the processing circuit 23 and the host controller of the host device (not shown).

[0039] Figure 2 This is a schematic diagram showing a simplified cross-sectional configuration of the sensor section of the detection device according to Embodiment 1. The sensor section 10 includes a sensor substrate 11, an electrode 12, a shielding electrode 14, and an electrode protective layer 15. For example, a glass cover can be shown as the electrode protective layer 15.

[0040] In the sensor unit 10, the electrode protective layer 15 is provided with an adhesive layer OC spaced between it and one side of the sensor substrate 11 on which a plurality of electrodes 12 are provided. A shielding electrode 14 is provided on the other side of the sensor substrate 11. The sensor unit 10 consists of the sensor substrate 11, the electrodes 12, and the electrode protective layer 15 stacked sequentially from the shielding electrode 14, forming a detection area AA.

[0041] In this disclosure, a hygroscopic front surface cover 16 is provided on the surface of the electrode protective layer 15. In other words, the detection area AA of the sensor unit 10 is covered by the front surface cover 16.

[0042] The front surface cover 16 is a component made of a non-conductive material with hygroscopic properties. Specifically, examples of the front surface cover 16 include wood, natural fibers, natural leather, or synthetic fibers and synthetic leather that mimic the appearance and feel of nature. Alternatively, the front surface cover 16 may also be a component such as diatomaceous earth, plaster, or gypsum board.

[0043] Figure 3 This is a block diagram showing an example of the configuration of the detection unit of the detection device according to Embodiment 1.

[0044] like Figure 3 As shown, the detection unit 20 includes a signal detection unit 42, an A / D conversion unit 43, a signal processing unit 44, a coordinate calculation unit 45, and a storage unit 46. The signal detection unit 42 and the A / D conversion unit 43 are included in the detection circuit 22. The signal processing unit 44, the coordinate calculation unit 45, and the storage unit 46 are included in the processing circuit 23.

[0045] The signal detection unit 42 generates a detection value (Rawdata) for each electrode 12 based on the detection signal Det output from the sensor substrate 11. The A / D conversion unit 43 samples the detection value of each electrode 12 and converts it into a digital signal.

[0046] The signal processing unit 44 performs various processing on the detection value Rawdata of each electrode 12, such as baseline processing and linear transformation processing, and outputs it as the detection value S of each electrode 12.

[0047] The coordinate calculation unit 45 extracts the spatial coordinates of the location of the object being detected based on the detection values ​​S of the multiple electrodes 12 within the detection area AA.

[0048] The storage unit 46 stores various parameters, tables, etc., used in the processing of the signal processing unit 44 and the coordinate calculation unit 45. In addition, the storage unit 46 has the function of storing intermediate data processed in the signal processing unit 44 and the coordinate calculation unit 45.

[0049] Figure 4AIt is a schematic diagram showing the relationship between the position of the object being detected in the space of the detection area and the position of each electrode. Figure 4B This is a schematic diagram showing the spatial coordinates of the object being detected in the space of the detection area. Figure 4A and Figure 4B The image shows an example of the object F being detected existing in the space of the detection area AA.

[0050] In the detection area AA, an electrostatic capacitance is generated in each electrode 12, corresponding to the distance D between the object to be detected F and each electrode 12 in the space of the detection area AA. The detection value Rawdata corresponding to this electrostatic capacitance is acquired by the detection circuit 22. The detection value Rawdata acquired by the detection circuit 22 is processed by the signal processing unit 44 through various processes such as baseline processing and linear transformation processing, thereby generating the detection value S for each electrode 12.

[0051] The coordinate calculation unit 45 calculates the representation based on the detection value S of each electrode 12 generated by the signal processing unit 44. Figure 4B The spatial coordinates R (Rx, Ry, Rz) of the position of the object F in the space of the detection area AA shown.

[0052] In this disclosure, the spatial coordinates R(Rx, Ry, Rz) include data Rx representing the position of the Dx direction (first direction) on the detection area AA, data Ry representing the position of the Dy direction (second direction) on the detection area AA, and data Rz representing the position of the Dz direction (third direction) which is orthogonal to the Dx and Dy directions.

[0053] The spatial coordinates R (Rx, Ry, Rz) represent the position of the object under test F with the surface of the electrode protective layer 15 as the reference plane. In other words, in this disclosure, the object under test F exists at a position relative to the detection area AA, separated by the front surface cover 16.

[0054] As described above, the detection device 1 disclosed herein detects the spatial coordinates of the location of the object F in the detection area AA by detecting the electrostatic capacitance generated on each electrode 12. Therefore, in order to detect the object F located at a position separated from the detection area AA in the Dz direction, it is necessary to increase the size of each electrode 12 to improve sensitivity compared to detecting the planar coordinates of the contact position between the object F and the detection surface. Generally, it is desirable for each electrode 12 to be, for example, 20mm × 20mm or more and about 40mm × 40mm, specifically, about 30mm × 30mm is envisioned.

[0055] Here, the baseline processing in the signal processing unit 44 will be explained. Figure 5 This is a diagram showing an example of the connection configuration between the sensor section and the detection section of the detection device according to Embodiment 1.

[0056] like Figure 5 As shown, the signal detection unit 42 of the detection circuit 22 has a differential amplifier circuit CA as its main component. The detection device 1 disclosed herein is a detection device that detects the self-capacitance of the object to be detected F by generating an electric field through multiple electrodes 12.

[0057] The power supply circuit 24 supplies a detection drive signal VD to the non-inverting input terminal of the differential amplifier circuit CA. The drive signal VD is a rectangular wave signal that repeats high and low potentials according to a specified period.

[0058] Electrode 12, located in the detection area AA, is connected to another inverting input terminal of the differential amplifier circuit CA. Additionally, a negative feedback capacitor Cfb is placed between the inverting input terminal and the output terminal of the differential amplifier circuit CA. The differential amplifier circuit CA functions as an integrator circuit by supplying a drive signal VD to the non-inverting input terminal.

[0059] The power supply circuit 24 supplies a drive signal VD to the shielding electrode 14.

[0060] Let S(Cdet) be the component caused by the capacitance Cdet generated between the object being tested F and the electrode 12, and let S(Cp) be the component caused by the parasitic capacitance Cp. The detection value Rawdata acquired during the detection action is represented by the following formula (1).

[0061] Rawdata=S(Cdet)+S(Cp)…(1)

[0062] The signal processing unit 44 pre-sets the detection value obtained when there is no detected object F in the space that can be detected in the detection area AA as the baseline BL (=S(Cp)). By subtracting the baseline BL from the detection value Rawdata of each electrode 12 obtained during normal detection operation, the component S(Cdet) after removing the component (S(Cp)) caused by parasitic capacitance Cp is obtained as the signal value Signal of each electrode 12.

[0063] Furthermore, as described above, the detection device 1 disclosed herein has a front surface cover 16 covering the detection area AA on the surface of the electrode protective layer 15 of the sensor section 10. The dielectric constant of the front surface cover 16, which is made of a hygroscopic non-conductive material, changes with humidity. Therefore, the detection accuracy of the object F, which exists at a position relative to the detection area AA through the front surface cover 16, may be reduced.

[0064] In the detection apparatus 1 disclosed herein, the signal processing unit 44, in addition to the baseline processing described above, corrects the detection value acquired when a detection action of detecting the subject F is performed, based on the detection value acquired when no undetected action of the subject F is detected. Hereinafter, the specific operation of the detection apparatus 1 according to Embodiment 1 will be described.

[0065] Figure 6 This is a flowchart illustrating an example of the specific operations and processes in the detection device according to Embodiment 1.

[0066] When the detection device 1 is activated (step S101), the signal processing unit 44 of the detection unit 20 acquires the signal value Signal of each electrode 12 (step S102) and performs a comparison operation between the acquired signal value Signal of each electrode 12 and the correction coefficient setting threshold Sigth. Specifically, the signal processing unit 44 determines whether the signal value Signal of each electrode 12 acquired in step S102 is below the correction coefficient setting threshold Sigth (step S103).

[0067] Here, the correction coefficient setting threshold Sigth is a threshold used to determine whether the correction coefficient setting process (step S200) described later can be performed. The correction coefficient setting process (step S200) described later needs to be performed when there is no object F to be detected in the space that can be detected in the detection area AA. If the signal value Signal of each electrode 12 obtained in step S102 is below the correction coefficient setting threshold Sigth (step S103; "Yes"), the signal processing unit 44 determines that there is no object F to be detected in the space that can be detected in the detection area AA. On the other hand, if the signal value Signal of each electrode 12 obtained in step S102 is greater than the correction coefficient setting threshold Sigth (step S103; "No"), the signal processing unit 44 determines that there is an object F to be detected in the space that can be detected in the detection area AA.

[0068] If the signal value Signal of each electrode 12 obtained in step S102 is greater than the correction coefficient setting threshold Sigth (step S103; "No"), in other words, if it is determined that there is a detected object F in the space that can be detected in the detection area AA, the signal processing unit 44 repeatedly executes the processing of steps S102 and S103.

[0069] If the signal value Signal of each electrode 12 obtained in step S102 is below the correction coefficient setting threshold Sigth (step S103; "Yes"), in other words, if it is determined that there is no object F to be detected in the space that can be detected in the detection area AA, the detection unit 20 resets the correction coefficient setting process execution timer T (T=0, step S104) and performs the correction coefficient setting process (step S200). Figure 7 This is a sub-flowchart illustrating an example of the correction coefficient setting process in the detection apparatus according to Embodiment 1. Figure 8 This is a conceptual diagram illustrating the calibration coefficient setting operation of the detection device involved in Embodiment 1.

[0070] When transferred to Figure 7 When setting the correction coefficient as shown, such as Figure 8 As shown, a reference potential Vref is supplied from the power supply circuit 24 to a portion of the electrodes 12-1 (hereinafter also referred to as "first electrode 12-1") within the detection area AA (step S201). Thus, the first electrode 12-1 is fixed at the reference potential Vref. The reference potential Vref can be exemplified, for example, by the GND potential.

[0071] In this state, i.e., when the first electrode 12-1 is fixed at the reference potential Vref (step S201), the signal processing unit 44 acquires the signal value Signal of the electrode 12-2 (hereinafter also referred to as "second electrode 12-2") other than the first electrode 12-1 in the detection area AA (step S202), and uses... Figure 9 The scheme shown describes the correspondence between the signal value Signal acquired during the correction coefficient setting operation and the correction coefficient k corresponding to the moisture content of the front surface cover 16. The correction coefficient k is acquired (step S203) and stored in the storage unit 46 (step S204). Returning to the previous step... Figure 6 The processing shown.

[0072] Figure 9 This is a schematic diagram illustrating an example of the correspondence between the signal value acquired during the correction factor setting operation and the correction factor corresponding to the moisture content of the front surface cover. In this disclosure, Figure 9 The correspondence of the schemes shown is pre-stored in the storage unit 46.

[0073] When the correction coefficient setting action is performed in the detection area AA, where the detected object F is not present, the acquired signal value Signal is correlated with the moisture content of the front surface cover 16. Specifically, the signal value Signal is proportional to the parasitic capacitance Cp between the first electrode 12-1 and the second electrode 12-2, and the parasitic capacitance Cp between the first electrode 12-1 and the second electrode 12-2 varies according to the moisture content of the front surface cover 16. In this disclosure, according to Figure 9 The correction coefficient k derived from the corresponding relationship of the scheme shown is set such that the detection value S detected when the object to be detected F exists in the space where detection can be performed on the detection area AA is not dependent on the moisture content of the front surface cover 16 and is approximately constant.

[0074] More specifically, in this disclosure, a correction coefficient k = 1.0 is set for the reference signal value Sigref when the moisture content of the front surface cover 16 is at a specified value. When the moisture content of the front surface cover 16 increases, the capacitance value of the parasitic capacitance Cp increases, and the signal value Signal acquired when detecting the object F increases. Conversely, when the moisture content of the front surface cover 16 is lower than the reference value, the capacitance value of the parasitic capacitance Cp decreases, and the signal value Signal acquired when detecting the object F decreases. Therefore, the correction coefficient k decreases monotonically as the signal value Signal acquired during the correction coefficient setting operation increases, and increases monotonically as the signal value Signal acquired during the correction coefficient setting operation decreases.

[0075] It should be pointed out that, in Figure 9 The example shown illustrates a function representing the correspondence between the signal value Signal acquired during the correction coefficient setting operation and the correction coefficient k corresponding to the moisture content of the front surface cover 16. However, it is also possible to pre-store a table representing this correspondence in the storage unit 46.

[0076] Back Figure 6 In the process shown, the signal processing unit 44 acquires the signal value Signal of each electrode 12 (step S105) and performs a comparison operation between the acquired signal value Signal and the correction coefficient setting threshold Sigth. Specifically, the signal processing unit 44 determines whether the signal value Signal of each electrode 12 acquired in step S105 is greater than the correction coefficient setting threshold Sigth (step S106).

[0077] If the signal value Signal of each electrode 12 acquired in step S105 is greater than the correction coefficient setting threshold Sigth (step S106; "Yes"), in other words, if it is determined that there is a detected object F in the space where detection can be performed on the detection area AA, the signal processing unit 44 applies the signal value Signal of each electrode 12 acquired in step S105 to the following: Figure 7 The correction coefficient k obtained in the correction coefficient setting process shown is used to perform the correction process (step S107) for the signal value Signal of each electrode 12 using the following formula (2). In (2) below, S represents the detection value of each electrode 12 after correction.

[0078] S = Signal × k … (2)

[0079] Then, the coordinate calculation unit 45 of the detection unit 20 calculates the representation based on the detection value S of each electrode 12 generated by the signal processing unit 44. Figure 4B The spatial coordinates R (Rx, Ry, Rz) of the position of the detected object F in the detection area AA shown in the detection area AA (step S108).

[0080] If the signal value Signal of each electrode 12 obtained in step S105 is below the correction coefficient setting threshold Sigth (step S106; "No"), in other words, if it is determined that there is no object F to be detected in the space where detection can be performed on the detection area AA, the detection unit 20 determines whether the correction coefficient setting process execution timer T is above the correction coefficient setting process execution threshold Tth (e.g., 1 hour) (step S109).

[0081] If the timer T for the correction coefficient setting process is less than the threshold Tth for the correction coefficient setting process (step S109; "No"), return to the process in step S105 and repeat step S105 and subsequent processes.

[0082] When the timer T for setting the correction coefficient is above the threshold Tth (step S109; "Yes"), return to the process in step S104 and repeat step S104 and subsequent processes.

[0083] In the processing of the detection device 1 according to Embodiment 1, firstly, when the detection device 1 is started (step S101), if it is determined that there is no object F to be detected in the space where detection can be performed on the detection area AA (step S103; "Yes"), the following steps are executed: Figure 7The correction coefficient setting process is shown (step S200). Additionally, if it is determined that there is no object F to be detected in the space where detection can be performed on the detection area AA (step S106; "No"), and the correction coefficient setting process execution timer T is equal to or greater than the correction coefficient setting process execution threshold Tth (e.g., 1 hour) (step S109; "Yes"), the following steps are executed: Figure 7 The correction coefficient setting process is shown in step S200.

[0084] Then, if it is determined that there is a detected object F in the space where detection can be performed on the detection area AA (step S106; "Yes"), the correction coefficient k obtained in the correction coefficient setting process (step S200) is applied to the signal value Signal of each electrode 12, and the corrected detection value S is calculated (step S107).

[0085] Therefore, it is possible to suppress the decrease in detection accuracy caused by the change in the dielectric constant of the front surface cover 16 as humidity changes.

[0086] (Modified example)

[0087] Figure 10 This is a sub-flowchart illustrating an example of the correction coefficient setting process involved in a variation of Embodiment 1. Figure 11A and Figure 11B This is a conceptual diagram illustrating the correction coefficient setting operation involved in a variation of Implementation 1.

[0088] In the correction coefficient setting process involved in the variation of Implementation 1, firstly, in such a way... Figure 11A As shown in step S201a, when the power supply circuit 24 supplies a reference potential Vref to the first electrode 12-1 of the first electrode 12-1 and the second electrode 12-2, which are alternately arranged in the Dx direction (first direction) and the Dy direction (second direction) within the detection region AA, the signal processing unit 44 acquires the signal value Signal of the second electrode 12-2 (step S202a) and uses it... Figure 9 The scheme shown obtains the correspondence between the signal value Signal acquired during the correction coefficient setting operation and the correction coefficient k corresponding to the moisture content of the front surface cover 16, acquires the correction coefficient k of each second electrode 12-2 (step S203a), and stores it in the storage unit 46 (step S204a).

[0089] Then, in such Figure 11BIn the state shown, when the reference potential Vref is supplied from the power supply circuit 24 to the second electrode 12-2 of the first electrode 12-1 and the second electrode 12-2 that are alternately arranged in the Dx direction (first direction) and the Dy direction (second direction) within the detection area AA (step S205a), the signal processing unit 44 acquires the signal value Signal of the first electrode 12-1 (step S206a) and uses it... Figure 9 The diagram shows the correspondence between the signal value Signal acquired during the correction coefficient setting operation and the correction coefficient k corresponding to the moisture content of the front surface cover 16. The correction coefficient k for each first electrode 12-1 is acquired (step S207a) and stored in the storage unit 46 (step S208a). Returning to... Figure 6 The processing shown.

[0090] Then, in Figure 6 In the detection value correction process shown in step S107, the signal processing unit 44 applies the signal value Signal of each electrode 12 to the signal processing unit 44 respectively. Figure 10 The correction coefficient k obtained in the correction coefficient setting process shown is used to perform correction processing on the signal value Signal of each electrode 12.

[0091] Thus, for example, even if the fiber density of the front surface cover 16, which is made of natural wood, natural fiber, natural leather, etc., which covers the detection area AA, is uneven and the dielectric constant is not uniformly distributed in the detection area AA, the signal value of each electrode 12 can be properly corrected.

[0092] (Implementation Method 2)

[0093] Figure 12 This is a top view showing a first example of the electrode configuration in the sensor section of the detection device according to Embodiment 2. Figure 13 This is a schematic diagram showing a first example of a simplified cross-sectional configuration of the sensor section of the detection device according to Embodiment 2.

[0094] exist Figure 12 and Figure 13 In the configuration of the sensor unit 10a shown in the first example, multiple electrodes 12 arranged in the Dx direction (first direction) and Dy direction (second direction) are each surrounded by a grid-like shielding electrode 14a within the detection area AA. In the configuration of Embodiment 2, similar to the shielding electrode 14, a drive signal VD is supplied to the shielding electrode 14a from the power supply circuit 24.

[0095] Figure 14 This is a top view showing a second example of the electrode configuration in the sensor section of the detection device according to Embodiment 2. Figure 15This is a schematic diagram showing a second example of a simplified cross-sectional configuration of the sensor section of the detection device according to Embodiment 2. Figure 12 and Figure 13 In the configuration of the sensor section 10a shown in the first example, an example is illustrated where multiple electrodes 12 and shielding electrodes 14a are provided on the same side of the sensor substrate 11. However, Figure 14 and Figure 15 In the configuration of the sensor section 10b shown in the second example, an example is shown in which the four sides of the electrode 12 overlap with the shielding electrode 14a in the Dz direction (third direction).

[0096] The following are examples. Figure 12 and Figure 13 The configuration of the sensor unit 10a shown in the first example will be used to explain the operation of setting the correction coefficient of the detection device 1a according to Embodiment 2. Figure 16 This is a sub-flowchart illustrating an example of the correction coefficient setting process in the detection device according to Embodiment 2. Figure 17 This is a conceptual diagram illustrating the calibration coefficient setting operation of the detection device involved in Embodiment 2.

[0097] In the correction coefficient setting process involved in Implementation Method 2, such as Figure 17 As shown, a drive signal VD is supplied from the power supply circuit 24 to the shielding electrode 14a (hereinafter also referred to as "first electrode 14a") (step S201b).

[0098] In this state, that is, in the state where a drive signal VD is supplied to the first electrode 14a (step S201b), the signal processing unit 44 acquires the signal values ​​Signal of the plurality of electrodes 12 (hereinafter also referred to as "second electrode 12") (step S202b), and uses Figure 9 The scheme shown establishes a correspondence between the signal value Signal acquired during the correction coefficient setting operation and the correction coefficient k corresponding to the moisture content of the front surface cover 16. The correction coefficient k for each second electrode 12 is acquired (step S203b) and stored in the storage unit 46 (step S204b). Returning to the previous step... Figure 6 The processing shown.

[0099] Then, in Figure 6 In the detection value correction process shown in step S107, the signal processing unit 44 applies the signal value Signal of each electrode 12 to the signal processing unit 44 respectively. Figure 16 The correction coefficient k obtained in the correction coefficient setting process shown is used to perform correction processing on the signal value Signal of each electrode 12. It should be noted that this can also be done in... Figure 6The scheme in steps S102 and S105 is to set the shielding electrode 14a to a floating state when obtaining the signal value Signal of each electrode 12.

[0100] Thus, similar to the variations of Embodiment 1, for example, even if the fiber density of the front surface cover 16, which covers the detection area AA, such as wood, natural fiber, or natural leather, is uneven and the dielectric constant is not uniformly distributed within the detection area AA, the signal value Signal of each electrode 12 can be appropriately corrected.

[0101] The preferred embodiments of this disclosure have been described above, but this disclosure is not limited to such embodiments. The content disclosed in the embodiments is merely an example, and various modifications can be made without departing from the spirit of this disclosure. Appropriate modifications made without departing from the spirit of this disclosure are, of course, also within the technical scope of this disclosure.

[0102] Explanation of reference numerals in the attached figures

[0103] 1. Detection device; 10, 10a, 10b. Sensor section; 11. Sensor substrate; 12. Electrode (second electrode); 12-1. First electrode; 12-2. Second electrode; 13. Wiring; 14. Shielding electrode; 14a. Shielding electrode (first electrode); 15. Electrode protective layer; 16. Front surface cover; 20. Detection section; 21. Control substrate; 22. Detection circuit; 23. Processing circuit; 24. Power supply circuit; 25. Interface circuit; 31. Wiring substrate; 42. Signal detection section; 43. A / D conversion section; 44. Signal processing section; 45. Coordinate calculation section; 46. Storage section; AA. Detection area; F. Detected object; OC. Adhesive layer.

Claims

1. A detection device comprising: The detection area is equipped with multiple electrodes; A front surface cover, made of a hygroscopic, non-conductive material, covers the detection area; and The detection unit detects the object being tested near the detection area through the front surface cover. The detection unit obtains a correction coefficient for correcting the signal value obtained when the detected object is detected, based on the correspondence between the signal value obtained when the undetected action of the detected object is not detected and the moisture content of the front surface cover.

2. The detection device according to claim 1, wherein, When no action is detected, the detection unit acquires the correction coefficient of each of the plurality of electrodes.

3. The detection device according to claim 1 or 2, wherein, The detection unit acquires the correction coefficient after the power to the detection device is turned on.

4. The detection device according to claim 3, wherein, The detection unit acquires the correction coefficient at predetermined intervals.

5. The detection device according to claim 4, wherein, When no action is detected, the detection unit fixes the potential of a portion of the electrodes among the plurality of electrodes and obtains the correction coefficient based on the signal value of the electrodes whose potentials are not fixed.

6. The detection device according to claim 4, wherein, When no action is detected, the detection unit supplies a drive signal to a portion of the plurality of electrodes and obtains the correction coefficient based on the signal value of the electrodes for which no drive signal is supplied.

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