Detection device and detection system

Abstract

To provide a detection device and a detection system which can suppress the deterioration in accuracy of acquisition of proximity detection coordinates.SOLUTION: A detection device includes: a detection region AA in which a plurality of electrodes 12 arrayed in first and second directions are arranged; a signal processing section for generating detection values S (m, n) for each of the electrodes 12; and a coordinate calculation section for calculating data indicating a second-direction position of a detected body in the detection region AA on the basis of the detection values S (m, n) of the plurality of electrodes 12 arrayed in the second direction. The plurality of electrodes 12 have a rectangular shape with a second-direction width smaller than a first-direction width.SELECTED DRAWING: Figure 10

Description

Technical Field

[0001] The present invention relates to a detection device and a detection system.

Background Art

[0002] In recent years, a detection system in which a detection device capable of detecting an external proximity object, so-called a touch panel, is mounted or integrated on a display device such as a liquid crystal display device has been known (see, for example, Patent Documents 1 to 3). In such a detection system, in addition to a touch detection function for detecting contact of a detection surface with a detection object such as an operator's finger, a hover detection function for detecting the proximity state or gesture of a finger in the space on the detection area with no finger touching the detection surface has attracted attention.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a configuration where a plurality of electrodes are provided in a detection region, the capacitance generated in each electrode is detected, and the spatial coordinates of the position where the object to be detected exists on the detection region are detected, it is necessary to increase the sensitivity by increasing the size of each electrode as compared with a configuration for detecting the planar coordinates of the touch detection position. In such a configuration, using the detection values of the plurality of electrodes, the spatial coordinates of the object to be detected on the detection region are calculated by a method such as centroid calculation. However, for example, when the size of the touch panel is small, the number of electrodes provided on the detection region decreases, so there is a possibility that the acquisition accuracy of the proximity detection coordinates decreases.

[0005] An object of the present invention is to provide a detection device and a detection system capable of improving coordinate acquisition accuracy.

Means for Solving the Problems

[0006] A detection device according to an aspect of the present invention includes a detection region provided with a plurality of electrodes arranged in a first direction and a second direction different from the first direction, a signal processing unit that generates a detection value for each electrode, and coordinates based on the detection values of the plurality of electrodes arranged in the second direction. A coordinate calculation unit that calculates data indicating the position of the object to be detected in the second direction on the detection region, and the shapes of the plurality of electrodes are rectangular shapes in which the width in the second direction is smaller than the width in the first direction.

[0007] A detection system according to an aspect of the present invention includes the above detection device, and a display panel disposed to face a sensor substrate provided with a plurality of the electrodes via an air gap, and in a plan view, the detection region and the display region of the display panel are orthogonal to the first direction and the second direction. They overlap in the third direction.

Brief Description of the Drawings

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MODE FOR CARRYING OUT THE INVENTION

[0009] Embodiments (embodiments) for carrying out the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited by the content described in the following embodiments. In addition, the constituent elements described below include those that can be easily assumed by those skilled in the art and those that are substantially the same. Furthermore, the constituent elements described below can be combined as appropriate. In addition, the disclosure is merely an example, and those that can be easily conceived by those skilled in the art with appropriate modifications while maintaining the gist of the invention are naturally included in the scope of the present invention. In addition, for the purpose of making the description clearer, the drawings may schematically represent the width, thickness, shape, etc. of each part compared to the actual aspect, but this is merely an example and does not limit the interpretation of the present invention. Also, in this specification and each drawing, the same reference numerals may be given to the same elements as those described above with respect to the already shown drawings, and detailed descriptions may be omitted as appropriate.

[0010] (Embodiment 1) FIG. 1 is a plan view showing a schematic configuration of a detection device applied to the detection system according to the present disclosure. As shown in FIG. 1, the detection device 1 includes a sensor unit 10 and a control unit 20.

[0011] The sensor unit 10 includes a sensor substrate 11, a plurality of electrodes 12 provided in a detection region AA of the sensor substrate 11, and wirings 13 extending from each of the plurality of electrodes 12. The control 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.

[0012] The detection region AA of the sensor substrate 11 is a region where a plurality of electrodes 12 arranged in a matrix in the Dx direction and the Dy direction are provided. In FIG. 1, a configuration in which M (5 in FIG. 1) electrodes 12 are arranged in the Dx direction and N (4 in FIG. 1) electrodes 12 are arranged in the Dy direction is illustrated. The sensor substrate 11 is, for example, a glass substrate or a flexible printed circuit (FPC) having translucency.

[0013] In the present disclosure, the Dx direction and the Dy direction are orthogonal in the detection region AA of the sensor substrate 11. Also, in the present disclosure, a direction orthogonal to the Dx direction and the Dy direction is defined as the Dz direction.

[0014] In the example shown in FIG. 1, an example in which 5×4 (=20) electrodes 12 are provided with 5 electrodes 12 arranged in the Dx direction and 4 electrodes 12 arranged in the Dy direction is shown, but the number of electrodes 12 provided in the detection region AA of the sensor substrate 11 is not limited to this.

[0015] The control substrate 21 is electrically connected to the sensor substrate 11 via a wiring substrate 31. The wiring substrate 31 is, for example, a flexible printed circuit. Each electrode 12 of the sensor unit 10 is connected to the detection circuit 22 of the control unit 20 via the wiring substrate 31.

[0016] The control board 21 is provided with a detection circuit 22, a processing circuit 23, a power supply circuit 24, and an interface circuit 25. The control board 21 is, for example, a rigid board.

[0017] Based on the detection signals of the respective electrodes 12 output from the sensor board 11, the detection circuit 22 generates detection values of the respective electrodes 12. The detection circuit 22 is, for example, an analog front end (AFE) IC.

[0018] Based on the detection values of the respective electrodes 12 output from the detection circuit 22, the processing circuit 23 generates spatial coordinates indicating the position where the object to be detected (for example, the finger of an operator, etc.) exists on the detection area AA. The processing circuit 23 may be, for example, a programmable logic device (PLD) such as a field programmable gate array (FPGA), or may be, for example, a micro control unit (MCU).

[0019] The power supply circuit 24 is a circuit that supplies power to the detection circuit 22 and the processing circuit 23.

[0020] The interface circuit 25 is, for example, a USB controller IC, and is a circuit that performs communication control between the processing circuit 23 and a host controller (not shown) of a host device on which the detection system is mounted.

[0021] FIG. 2 is a schematic cross-sectional configuration diagram showing the detection system.

[0022] The detection system 100 according to Embodiment 1 includes a detection device 1 and a display panel 200. The display panel 200 is disposed to face the sensor unit 10 of the detection device 1 with an air gap AG therebetween. The sensor unit 10 of the detection device 1 is arranged such that the detection area AA of the sensor unit 10 and the display area DA of the display panel 200 overlap in the Dz direction in a plan view. The display panel 200 is exemplified by, for example, a liquid crystal display (LCD: Liquid Crystal Display). The display panel 200 may be, for example, an organic EL display (OLED: Organic Light Emitting Diode) or an inorganic EL display (micro LED, mini LED).

[0023] The sensor unit 10 includes a sensor substrate 11, electrodes 12, a shield 14, and a cover glass 15. The sensor unit 10 is laminated in the order of the shield 14, the sensor substrate 11, the electrodes 12, and the cover glass 15 from the display panel 200 side. Hereinafter, the surface of the cover glass 15 provided on the uppermost layer is also referred to as the "detection surface".

[0024] The shield 14 is provided on the first surface of the sensor substrate 11 on the display panel 200 side. The electrodes 12 are provided on the second surface on the back side of the first surface of the sensor substrate 11. The cover glass 15 is provided on the second surface of the sensor substrate 11 via an adhesive layer OC. It is desirable that the adhesive layer OC employs a light-transmissive adhesive. The adhesive layer OC may be formed of a light-transmissive film having double-sided adhesiveness, such as OCA (Optical Clear Adhesive), for example.

[0025] FIG. 3 is a block diagram showing a configuration example of a detection unit of the detection device.

[0026] As shown in FIG. 3, the detection unit 40 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.

[0027] The signal detection unit 42 generates the output value Rawdata(m,n) of each electrode 12 based on the detection signal Det(m,n) of each electrode 12 output from the sensor substrate 11 (where m is a natural number from 1 to M, M is the number of electrodes arranged in the Dx direction in the detection region AA, n is a natural number from 1 to N, and N is the number of electrodes arranged in the Dy direction in the detection region AA). The A / D conversion unit 43 samples the output value of each electrode 12 and converts it into a digital signal. In the present disclosure, Rawdata(m,n) represents the output value of the electrode 12 in the m-th column and n-th row.

[0028] The signal processing unit 44 performs a linear conversion process on the output value Rawdata(m,n) of each electrode 12 and outputs it as the detection value S(m,n) of each electrode 12. In the present disclosure, S(m,n) represents the detection value of the electrode 12 in the m-th column and n-th row.

[0029] The coordinate calculation unit 45 extracts the spatial coordinates of the position where the object to be detected exists based on the detection value S(m,n) of each electrode 12.

[0030] 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. Further, the storage unit 46 has a function of storing intermediate data, etc. in the processing of the coordinate calculation unit 45.

[0031] FIG. 4A is a schematic diagram showing the positional relationship between the position of the object to be detected in the space on the detection region and each electrode. FIG. 4B is a schematic diagram showing the spatial coordinates of the object to be detected in the space on the detection region. FIGS. 4A and 4B show an example where the object to be detected F exists in the space on the detection region AA.

[0032] On each electrode 12 in the detection region AA, a capacitance corresponding to the distance D(m,n) between the detected object F existing in the space above the detection region AA and each electrode 12 is generated, and an output value Rawdata(m,n) corresponding to the capacitance is acquired by the detection circuit 22. The Rawdata(m,n) acquired by the detection circuit 22 is subjected to a linear conversion process by the signal processing unit 44. As a result, as shown in FIG. 4A, a detection value S(m,n) for each electrode 12 is generated.

[0033] Based on the detection value S(m,n) of each electrode 12 generated by the signal processing unit 44, the coordinate calculation unit 45 calculates a spatial coordinate R(Rx, Ry, Rz) indicating the position of the detected object F in the space above the detection region AA shown in FIG. 4B.

[0034] In the present disclosure, the spatial coordinate R(Rx, Ry, Rz) includes data Rx indicating the position in the Dx direction on the detection region AA, data Ry indicating the position in the Dy direction on the detection region AA, and data Rz indicating the position in the Dz direction orthogonal to the Dx direction and the Dy direction.

[0035] Also, in the present disclosure, the spatial coordinate R(Rx, Ry, Rz) indicates the position of the detected object F existing in the space on the detection surface with the surface of the cover glass 15 as the detection surface.

[0036] As described above, the detection device 1 according to the present disclosure is configured to detect the capacitance generated in each electrode 12 and detect the spatial coordinates of the position where the detected object F exists on the detection region AA. Therefore, in order to detect the detected object F existing at a position away from the detection region AA in the Dz direction, it is necessary to increase the sensitivity by increasing the size of each electrode 12 compared to a configuration that detects the planar coordinates of the contact position of the detected object F with the detection surface. Generally, the size of each electrode 12 is desirably, for example, 20 mm × 20 mm or more and about 40 mm × 40 mm, and specifically, about 30 mm × 30 mm is assumed.

[0037] FIG. 5A is a diagram showing a first example of the relationship between the distance between the detected object and the electrode and the output value. FIG. 5B is a diagram showing a second example of the relationship between the distance between the detected object and the electrode and the output value. In FIG. 5A, the horizontal axis represents the distance D between the detected object F and the electrode 12, and the vertical axis represents the output value Rawdata. In FIG. 5A, BL in the vertical axis direction represents the output value when the distance D between the detected object F and the electrode 12 is infinite. The vertical axis of FIG. 5B represents the difference value Rawdata - BL between the output value Rawdata and BL.

[0038] As shown in FIG. 5A, as the distance D between the detected object F and the electrode 12 increases, the decrease rate of the output value Rawdata decreases. In other words, when the distance D between the detected object F and the electrode 12 becomes larger, the change rate of the output value Rawdata becomes smaller. For this reason, in the region where the output value Rawdata is below a certain level, the detection accuracy of the distance D between the detected object F and the electrode 12 decreases. Specifically, in the region below the lower limit value Lower_lim shown in FIG. 5A, the detection accuracy of the distance D between the detected object F and the electrode 12 cannot be maintained.

[0039] Also, as shown in FIG. 5A, as the distance D between the detected object F and the electrode 12 decreases, the increase rate of the output value Rawdata rises exponentially. In other words, when the distance D between the detected object F and the electrode 12 becomes smaller, the change rate of the output value Rawdata increases rapidly. For this reason, in the region where the output value Rawdata is above a certain level, the detection accuracy of the distance D between the detected object F and the electrode 12 decreases. In particular, in the detection device 1 according to the present disclosure, since the size of each electrode 12 is large, when the detected object F exists at a position close to or in contact with the detection surface, the change amount of the output value Rawdata with respect to the change amount of the distance D between the detected object F and the electrode 12 becomes large. Specifically, in the region larger than the upper limit value Upper_lim shown in FIG. 5A, the detection accuracy of the distance D between the detected object F and the electrode 12 cannot be maintained.

[0040] Therefore, in the present disclosure, in the region from the lower limit value Lower_lim to the upper limit value Upper_lim shown in FIG. 5A, the output value Rawdata is linearly transformed. Specifically, the signal processing unit 44 obtains the difference value Rawdata - BL between the output value Rawdata and BL shown in FIG. 5A (see FIG. 5B), and performs a linear transformation process on this difference value Rawdata - BL.

[0041] FIG. 6 is a diagram showing the relationship between the distance between the detected object and the electrode and the detected value after the linear transformation process. In FIG. 6, the horizontal axis represents the distance D between the detected object F and the electrode 12, and the vertical axis represents the detected value S after the linear transformation process.

[0042] The signal processing unit 44 derives the detected value S for each electrode 12 using a table showing the correspondence between the difference value Rawdata - BL shown in FIG. 5B and the detected value S shown in FIG. 6. The table showing the correspondence between the difference value Rawdata - BL and the detected value S may be, for example, in a form where the detected value S is set corresponding to the difference value Rawdata - BL, or in a form where a relational expression between the difference value Rawdata - BL and the detected value S is set. The table showing the correspondence between the difference value Rawdata - BL and the detected value S is stored, for example, in the storage unit 46 provided in the processing circuit 23.

[0043] Hereinafter, a specific example of the coordinate calculation process according to the embodiment will be described. Here, before describing the coordinate calculation process according to the embodiment, the coordinate calculation process according to the comparative example will be described.

[0044] FIGS. 7A, 7B, 7C, and 7D are schematic diagrams for explaining the coordinate calculation process procedure according to the comparative example. FIG. 8 is a flowchart showing a specific example of the coordinate calculation process according to the comparative example.

[0045] In FIGS. 7A, 7B, 7C, and 7D, a configuration is illustrated in which 4×5 (=20) electrodes 12 are arranged on the detection region AA. The black dots shown in FIGS. 7A, 7B, 7C, and 7D indicate the closest positions of the object F to be detected on the detection region AA. Also, in FIGS. 7A and 7B, a state is shown in which the object F is closest to the upper position on the electrodes 12 in two columns and three rows, and in FIGS. 7C and 7D, a state is shown in which the object F is closest to the lower position on the electrodes 12 in two columns and three rows.

[0046] In FIG. 8, an example of calculating the data Ry among the spatial coordinates R (Rx, Ry, Rz) of the object F to be detected will be described. Here, the data Ry is calculated by, for example, a known centroid calculation method using the detection values of three electrodes 12 arranged in the Dy direction including the electrode 12 having the maximum detection value S(m, n).

[0047] In the coordinate calculation process according to the comparative example, the coordinate calculation unit 45 extracts the electrode 12 having the maximum detection value S(m, n) and detects the detection value S(m, n) of the electrode 12 as the maximum detection value Smax (step S1). Here, an example is shown in which the detection value S(2, 3) of the electrodes 12 in two columns and three rows is detected as the maximum detection value Smax.

[0048] The coordinate calculation unit 45 calculates the first data Ry1 using the detection value S(2, 2) of the electrodes 12 in two columns and two rows, the detection value S(2, 3) of the electrodes 12 in two columns and three rows, and the detection value S(2, 4) of the electrodes 12 in two columns and four rows (step S2).

[0049] Subsequently, the coordinate calculation unit 45 determines whether the detection value S(2, 2) of the electrodes 12 in two columns and two rows is greater than or equal to the detection value S(2, 4) of the electrodes 12 in two columns and four rows (step S3).

[0050] As shown in FIG. 7A, when the object F to be detected is closest to the upper position on the electrodes 12 of two columns and three rows, the detection value S(2, 2) of the electrodes 12 of two columns and two rows becomes equal to or greater than the detection value S(2, 4) of the electrodes 12 of two columns and four rows (step S3; Yes). In this case, as shown in FIG. 7B, the second data Ry2 is calculated using the detection value S(2, 1) of the electrodes 12 of two columns and one row, the detection value S(2, 2) of the electrodes 12 of two columns and two rows, and the detection value S(2, 3) of the electrodes 12 of two columns and three rows (step S4).

[0051] On the other hand, as shown in FIG. 7C, when the object F to be detected is closest to the lower position on the electrodes 12 of two columns and three rows, the detection value S(2, 2) of the electrodes 12 of two columns and two rows becomes less than the detection value S(2, 4) of the electrodes 12 of two columns and four rows (step S3; No). In this case, as shown in FIG. 7D, the second data Ry2 is calculated using the detection value S(2, 3) of the electrodes 12 of two columns and three rows, the detection value S(2, 4) of the electrodes 12 of two columns and four rows, and the detection value S(2, 5) of the electrodes 12 of two columns and five rows (step S5).

[0052] The coordinate calculation unit 45 obtains a difference value a between the detection value S(2, 3) of the electrodes 12 of two columns and three rows and the detection value S(2, 2) of the electrodes 12 of two columns and two rows, and a difference value b between the detection value S(2, 3) of the electrodes 12 of two columns and three rows and the detection value S(2, 4) of the electrodes 12 of two columns and four rows (step S6). Subsequently, the coordinate calculation unit 45 calculates a detection value ratio ps using the following formula (1) (step S7), and derives a synthesis ratio pf using the data synthesis ratio table shown in FIG. 9 (step S8). FIG. 9 is a diagram showing an example of the data synthesis ratio table.

[0053] ps = a / (a + b) ··· (1)

[0054] The data synthesis ratio table shown in FIG. 9 may be, for example, a mode in which the synthesis ratio pf is set corresponding to the detection value ratio ps, or a mode in which a relational expression between the detection value ratio ps and the synthesis ratio pf is set. The data synthesis ratio table is stored, for example, in a storage unit 46 provided in the processing circuit 23.

[0055] Then, the coordinate calculation unit 45 calculates data Ry indicating the position of the detected object F in the Dy direction on the detection region AA using the following equation (2) (step S9).

[0056] Ry = Ry1×(1 - pf)+Ry2×pf ··· (2)

[0057] As shown in FIGS. 7A and 7B, when the detected object F is closest to the upper position on the two - row and three - column electrodes 12, the detection value S(2, 4) of the two - row and four - column electrodes 12 is larger than the detection value S(2, 2) of the two - row and two - column electrodes 12. As a result, the difference value a between the detection value S(2, 3) of the two - row and three - column electrodes 12 and the detection value S(2, 2) of the two - row and two - column electrodes 12 is smaller than the difference value b between the detection value S(2, 3) of the two - row and three - column electrodes 12 and the detection value S(2, 4) of the two - row and four - column electrodes 12. Therefore, by the processing from step S7 to step S9 using the above equation (1), the data synthesis ratio table shown in FIG. 9, and the above equation (2), the ratio of the first data Ry1 in the data Ry is larger than the ratio of the second data Ry2.

[0058] On the other hand, as shown in FIGS. 7C and 7D, when the detected object F is closest to the lower position on the two - row and three - column electrodes 12, the detection value S(2, 4) of the two - row and four - column electrodes 12 is smaller than the detection value S(2, 2) of the two - row and two - column electrodes 12. As a result, the difference value a between the detection value S(2, 3) of the two - row and three - column electrodes 12 and the detection value S(2, 2) of the two - row and two - column electrodes 12 is larger than the difference value b between the detection value S(2, 3) of the two - row and three - column electrodes 12 and the detection value S(2, 4) of the two - row and four - column electrodes 12. Therefore, by the processing from step S7 to step S9 using the above equation (1), the data synthesis ratio table shown in FIG. 9, and the above equation (2), the ratio of the first data Ry1 in the data Ry is smaller than the ratio of the second data Ry2.

[0059] In this way, by using the detection values of the plurality of electrodes 12, the first data Ry1 and the second data Ry2 corresponding to the position on the electrode closest to the object F to be detected are obtained, and further, by synthesizing the first data Ry1 and the second data Ry2 at a ratio corresponding to the position on the electrode closest to the object F to be detected, the coordinate acquisition accuracy can be improved.

[0060] FIG. 10 is a first diagram showing the detection area of the detection device according to the embodiment. FIG. 11 is a second diagram showing the detection area of the detection device according to the embodiment.

[0061] In FIG. 10, an aspect having a horizontally long detection area AA whose width in the Dx direction is larger than the width in the Dy direction is illustrated. In the aspect shown in FIG. 10, the Dx direction corresponds to the "first direction". Also, in the aspect shown in FIG. 10, the Dy direction corresponds to the "second direction".

[0062] In FIG. 11, an aspect having a vertically long detection area AA whose width in the Dx direction is smaller than the width in the Dy direction is illustrated. In the aspect shown in FIG. 11, the Dx direction corresponds to the "second direction". Also, in the aspect shown in FIG. 11, the Dy direction corresponds to the "first direction".

[0063] In the aspect shown in FIG. 10, the shape of each electrode 12 is a rectangular shape whose width in the Dy direction (second direction) is smaller than the width in the Dx direction (first direction). Also, the size of each electrode 12 is, for example, such that the width in the Dx direction (first direction) is about 30 mm, while the width in the Dy direction (second direction) is about 30 to 70% of the width in the Dx direction (first direction). More specifically, the width in the Dy direction (second direction) is assumed to be about 9 mm to 21 mm. Note that the shape of each electrode 12 is not limited to a rectangle, and may be, for example, a rounded rectangle.

[0064] On the one hand, in the embodiment shown in FIG. 11, the shape of each electrode 12 is a rectangular shape in which the width in the Dx direction (second direction) is smaller than the width in the Dy direction (first direction). Also, the size of each electrode 12 is such that, for example, the width in the Dy direction (first direction) is about 30 mm, while the width in the Dx direction (second direction) is about 30% to 70% of the width in the Dy direction (first direction). More specifically, the width in the Dx direction (second direction) is assumed to be about 9 mm to 21 mm. Note that the shape of each electrode 12 is not limited to a rectangle and may be, for example, a rounded rectangle.

[0065] In such an embodiment, when the distance D between the object F to be detected and the electrode 12 is relatively large, a plurality of electrodes 12 arranged in the short side direction (second direction, Dy direction in FIG. 10, Dx direction in FIG. 11) are bundled into one electrode bundle, and coordinate calculation processing is performed using the combined detection value obtained by combining the detection values S(m,n) of the plurality of electrodes 12 included in the electrode bundle. In the present disclosure, the combined detection value is obtained, for example, by digitally adding the detection values of the plurality of electrodes 12.

[0066] More specifically, for example, in a region where the maximum detection value Smax is relatively small, coordinate calculation processing is performed using the detection values of a plurality (for example, three) of electrodes 12 including the electrode 12 whose detection value S(m,n) is the maximum detection value Smax, in the same manner as the coordinate calculation processing according to the above-described comparative example. Thereby, the coordinate acquisition accuracy of the object F at a relatively close position can be improved.

[0067] On the other hand, in a region where the maximum detection value Smax is relatively large, for example, a plurality (two in FIGS. 10 and 11) of electrodes 12 arranged in the short side direction (second direction, Dy direction in FIG. 10, Dx direction in FIG. 11) are bundled into one electrode bundle, the combined detection value obtained by combining the detection values S(m,n) of the plurality of electrodes 12 included in the electrode bundle is obtained, and coordinate calculation processing is performed using the combined detection values of a plurality (for example, three) of electrode bundles including the electrode bundle including the electrode 12 whose detection value S(m,n) is the maximum detection value Smax. Thereby, the coordinate acquisition accuracy of the object F at a relatively far position can be improved.

[0068] (Embodiment 1) In Embodiment 1, an example will be described in which the number of electrodes to be bundled is changed when performing coordinate calculation processing according to the magnitude of the maximum detection value Smax. More specifically, a first threshold value Sth1 and a second threshold value Sth2 larger than the first threshold value Sth1 are provided for the maximum detection value Smax. The first threshold value Sth1 and the second threshold value Sth2 are stored, for example, in a storage unit 46 provided in the processing circuit 23.

[0069] FIG. 12 is a flowchart showing a specific example of the coordinate calculation processing according to Embodiment 1. Here, similar to the description of the coordinate calculation processing according to the comparative example, an example of calculating the data Ry among the spatial coordinates R (Rx, Ry, Rz) of the detected object F will be described.

[0070] In the coordinate calculation processing according to Embodiment 1, the coordinate calculation unit 45 extracts the electrode 12 with the maximum detection value S (m, n), and detects the detection value S (m, n) of the electrode 12 as the maximum detection value Smax (step S001). Here, the detection value S (m, n) of the electrode 12 in the m-th column and n-th row detected as the maximum detection value Smax is referred to as "S (n)".

[0071] The coordinate calculation unit 45 determines whether or not the maximum detection value Smax detected in step S001 is less than or equal to the first threshold value Sth1 (step S002). When the maximum detection value Smax is less than or equal to the first threshold value Sth1 (step S002; Yes), the process proceeds to the first process shown in FIG. 13 (step S100).

[0072] FIG. 13 is a sub-flowchart showing a specific example of the first process of the coordinate calculation process according to Embodiment 1. FIGS. 14A, 14B, 14C, and 14D are schematic diagrams for explaining the first process procedure of the coordinate calculation process according to Embodiment 1. In FIGS. 14A, 14B, 14C, and 14D, a plurality of electrodes 12 arranged in the short side direction (second direction) on the detection region AA are illustrated. The black dots shown in FIGS. 14A, 14B, 14C, and 14D indicate the closest positions of the detected object F on the detection region AA. Further, FIGS. 14A and 14B show a state in which the detected object F is closest to the upper position on the n-th row of electrodes 12, and FIGS. 14C and 14D show a state in which the detected object F is closest to the lower position on the n-th row of electrodes 12.

[0073] When shifting to the first process shown in FIG. 13, the coordinate calculation unit 45 calculates the first data Ry1 using the detection value S(n - 1) of the electrodes 12 in the n - 1-th row, the detection value S(n) of the electrodes 12 in the n-th row, and the detection value S(n + 1) of the electrodes 12 in the n + 1-th row (step S101).

[0074] Subsequently, the coordinate calculation unit 45 determines whether the detection value S(n - 1) of the electrodes 12 in the n - 1-th row is greater than or equal to the detection value S(n + 1) of the electrodes 12 in the n + 1-th row (step S102).

[0075] As shown in FIG. 14A, when the detected object F is closest to the upper position on the n-th row of electrodes 12, the detection value S(n - 1) of the electrodes 12 in the n - 1-th row becomes greater than or equal to the detection value S(n + 1) of the electrodes 12 in the n + 1-th row (step S102; Yes). In this case, as shown in FIG. 14B, the second data Ry2 is calculated using the detection value S(n - 2) of the electrodes 12 in the n - 2-th row, the detection value S(n - 1) of the electrodes 12 in the n - 1-th row, and the detection value S(n) of the electrodes 12 in the n-th row (step S103).

[0076] On the other hand, as shown in FIG. 14C, when the object F to be detected is closest to the lower position on the n-th row of electrodes 12, the detected value S(n - 1) of the (n - 1)-th row of electrodes 12 is less than the detected value S(n + 1) of the (n + 1)-th row of electrodes 12 (step S102; No). In this case, as shown in FIG. 14D, the second data Ry2 is calculated using the detected value S(n) of the n-th row of electrodes 12, the detected value S(n + 1) of the (n + 1)-th row of electrodes 12, and the detected value S(n + 2) of the (n + 2)-th row of electrodes 12 (step S104).

[0077] The coordinate calculation unit 45 obtains the difference value a between the detected value S(n) of the n-th row of electrodes 12 and the detected value S(n - 1) of the (n - 1)-th row of electrodes 12, and the difference value b between the detected value S(n) of the n-th row of electrodes 12 and the detected value S(n + 1) of the (n + 1)-th row of electrodes 12 (step S105). Subsequently, the coordinate calculation unit 45 calculates the detection value ratio ps using the above formula (1) (step S106), and derives the synthesis ratio pf using the data synthesis ratio table shown in FIG. 9 (step S107).

[0078] Then, the coordinate calculation unit 45 calculates the data Ry indicating the position of the object F in the short side direction (second direction) on the detection region AA using the above formula (2) (step S108).

[0079] As shown in FIGS. 14A and 14B, when the object F to be detected is closest to the upper position on the n-th row of electrodes 12, the detected value S(n + 1) of the (n + 1)-th row of electrodes 12 is greater than the detected value S(n - 1) of the (n - 1)-th row of electrodes 12. As a result, the difference value a between the detected value S(n) of the n-th row of electrodes 12 and the detected value S(n - 1) of the (n - 1)-th row of electrodes 12 is smaller than the difference value b between the detected value S(n) of the n-th row of electrodes 12 and the detected value S(n + 1) of the (n + 1)-th row of electrodes 12. Therefore, by the processing from step S106 to step S108 using the above formula (1), the data synthesis ratio table shown in FIG. 9, and the above formula (2), the ratio of the first data Ry1 in the data Ry is greater than the ratio of the second data Ry2.

[0080] On the other hand, as shown in FIGS. 14C and 14D, when the object F to be detected is closest to the lower position on the n-th row of electrodes 12, the detection value S(n + 1) of the electrodes 12 on the (n + 1)-th row is smaller than the detection value S(n - 1) of the electrodes 12 on the (n - 1)-th row. As a result, the difference value a between the detection value S(n) of the electrodes 12 on the n-th row and the detection value S(n - 1) of the electrodes 12 on the (n - 1)-th row is larger than the difference value b between the detection value S(n) of the electrodes 12 on the n-th row and the detection value S(n + 1) of the electrodes 12 on the (n + 1)-th row. Therefore, by the processing from step S106 to step S108 using the above formula (1), the data synthesis ratio table shown in FIG. 9, and the above formula (2), the ratio of the first data Ry1 in the data Ry is smaller than the ratio of the second data Ry2.

[0081] In an aspect of the embodiment, as shown in FIGS. 10 and 11, the width of the electrode 12 in one direction (second direction) is narrower than the width in the other direction (first direction). In such an aspect, when the maximum detection value Smax is equal to or less than the first threshold value Sth1 (step S002; Yes), using the detection values of the plurality of electrodes 12 arranged in the short side direction (second direction), the first data Ry1 and the second data Ry2 corresponding to the position on the electrode closest to the object F to be detected are acquired. Further, the first data Ry1 and the second data Ry2 are synthesized at a ratio corresponding to the position on the electrode closest to the object F to be detected, and the data Ry indicating the position of the object F to be detected in the short side direction (second direction) on the detection region AA is calculated. Thereby, the coordinate acquisition accuracy when the maximum detection value Smax is equal to or less than the first threshold value Sth1 can be improved.

[0082] When the maximum detection value Smax exceeds the first threshold value Sth1 (step S002; No), subsequently, the coordinate calculation unit 45 determines whether the maximum detection value Smax is equal to or less than the second threshold value Sth2 (step S003). When the maximum detection value Smax is equal to or less than the second threshold value Sth2 (step S003; Yes), the coordinate calculation unit 45 shifts to the second process shown in FIG. 15 (step S200).

[0083] FIG. 15 is a sub flowchart showing a specific example of the second process of the coordinate calculation process according to Embodiment 1. FIGS. 16A, 16B, 16C, and 16D are schematic diagrams for explaining the second process procedure of the coordinate calculation process according to Embodiment 1.

[0084] When shifting to the second process shown in FIG. 15, the coordinate calculation unit 45 determines whether or not the detection value S(n−1) of the electrode 12 in the n−1 row is greater than or equal to the detection value S(n+1) of the electrode 12 in the n+1 row (step S201).

[0085] As shown in FIG. 16A, when the detection object F is closest to the upper position on the electrode 12 in the nth row, the detection value S(n−1) of the electrode 12 in the n−1 row becomes greater than or equal to the detection value S(n+1) of the electrode 12 in the n+1 row (step S201; Yes). In this case, as shown in FIG. 16A, the coordinate calculation unit 45 bundles the electrode 12 in the n−3 row and the electrode 12 in the n−2 row into one electrode bundle, and calculates the combined detection value T1 in the electrode bundle (step S202). The combined detection value T1 in the electrode bundle formed by bundling the electrode 12 in the n−3 row and the electrode 12 in the n−2 row is calculated as, for example, a combined value of the detection value S(n−3) of the electrode 12 in the n−3 row and the detection value S(n−2) of the electrode 12 in the n−2 row.

[0086] Further, as shown in FIG. 16A, the coordinate calculation unit 45 bundles the electrode 12 in the n−1 row and the electrode 12 in the nth row into one electrode bundle, and calculates the combined detection value T3 in the electrode bundle (step S203). The combined detection value T3 in the electrode bundle formed by bundling the electrode 12 in the n−1 row and the electrode 12 in the nth row is calculated as, for example, a combined value of the detection value S(n−1) of the electrode 12 in the n−1 row and the detection value S(n) of the electrode 12 in the nth row.

[0087] Further, as shown in FIG. 16A, the coordinate calculation unit 45 bundles the electrode 12 in the n+1 row and the electrode 12 in the n+2 row into one electrode bundle, and calculates the combined detection value T5 in the electrode bundle (step S204). The combined detection value T5 in the electrode bundle formed by bundling the electrode 12 in the n+1 row and the electrode 12 in the n+2 row is calculated as, for example, a combined value of the detection value S(n+1) of the electrode 12 in the n+1 row and the detection value S(n+2) of the electrode 12 in the n+2 row.

[0088] Then, the coordinate calculation unit 45 calculates the first data Ry1 by using the combined detection value T1 in the electrode bundle formed by bundling the electrodes 12 in the n-3 row and the electrodes 12 in the n-2 row, the combined detection value T3 in the electrode bundle formed by bundling the electrodes 12 in the n-1 row and the electrodes 12 in the n row, and the combined detection value T5 in the electrode bundle formed by bundling the electrodes 12 in the n+1 row and the electrodes 12 in the n+2 row (step S205).

[0089] Subsequently, as shown in FIG. 16B, the coordinate calculation unit 45 bundles the electrodes 12 in the n-2 row and the electrodes 12 in the n-1 row into one electrode bundle, and calculates the combined detection value T2 in the electrode bundle (step S206). The combined detection value T2 in the electrode bundle formed by bundling the electrodes 12 in the n-2 row and the electrodes 12 in the n-1 row is calculated as, for example, a combined value of the detection value S(n-2) of the electrodes 12 in the n-2 row and the detection value S(n-1) of the electrodes 12 in the n-1 row.

[0090] Also, as shown in FIG. 16B, the coordinate calculation unit 45 bundles the electrodes 12 in the n row and the electrodes 12 in the n+1 row into one electrode bundle, and calculates the combined detection value T4 in the electrode bundle (step S207). The combined detection value T4 in the electrode bundle formed by bundling the electrodes 12 in the n row and the electrodes 12 in the n+1 row is calculated as, for example, a combined value of the detection value S(n) of the electrodes 12 in the n row and the detection value S(n+1) of the electrodes 12 in the n+1 row.

[0091] Also, as shown in FIG. 16B, the coordinate calculation unit 45 bundles the electrodes 12 in the n+2 row and the electrodes 12 in the n+3 row into one electrode bundle, and calculates the combined detection value T6 in the electrode bundle (step S208). The combined detection value T6 in the electrode bundle formed by bundling the electrodes 12 in the n+2 row and the electrodes 12 in the n+3 row is calculated as, for example, a combined value of the detection value S(n+2) of the electrodes 12 in the n+2 row and the detection value S(n+3) of the electrodes 12 in the n+3 row.

[0092] Then, the coordinate calculation unit 45 calculates the second data Ry2 using the combined detection value T2 in the electrode bundle formed by bundling the electrodes 12 in the n-2 row and the electrodes 12 in the n-1 row, the combined detection value T4 in the electrode bundle formed by bundling the electrodes 12 in the n row and the electrodes 12 in the n+1 row, and the combined detection value T6 in the electrode bundle formed by bundling the electrodes 12 in the n+2 row and the electrodes 12 in the n+3 row (step S209).

[0093] As shown in FIG. 16C, when the detection object F is closest to the lower position on the electrodes 12 in the n row, the detection value S(n-1) of the electrodes 12 in the n-1 row is less than the detection value S(n+1) of the electrodes 12 in the n+1 row (step S201; No). In this case, as shown in FIG. 16C, the coordinate calculation unit 45 bundles the electrodes 12 in the n-2 row and the electrodes 12 in the n-1 row into one electrode bundle, and calculates the combined detection value T2 in the electrode bundle (step S210).

[0094] Also, as shown in FIG. 16C, the coordinate calculation unit 45 bundles the electrodes 12 in the n row and the electrodes 12 in the n+1 row into one electrode bundle, and calculates the combined detection value T4 in the electrode bundle (step S211).

[0095] Also, as shown in FIG. 16C, the coordinate calculation unit 45 bundles the electrodes 12 in the n+2 row and the electrodes 12 in the n+3 row into one electrode bundle, and calculates the combined detection value T6 in the electrode bundle (step S212).

[0096] Then, the coordinate calculation unit 45 calculates the first data Ry1 using the combined detection value T2 in the electrode bundle formed by bundling the electrodes 12 in the n-2 row and the electrodes 12 in the n-1 row, the combined detection value T4 in the electrode bundle formed by bundling the electrodes 12 in the n row and the electrodes 12 in the n+1 row, and the combined detection value T6 in the electrode bundle formed by bundling the electrodes 12 in the n+2 row and the electrodes 12 in the n+3 row (step S213).

[0097] Subsequently, as shown in FIG. 16D, the coordinate calculation unit 45 bundles the electrodes 12 in the n-3 row and the electrodes 12 in the n-2 row into one electrode bundle, and calculates the combined detection value T1 in the electrode bundle (step S214).

[0098] Further, as shown in FIG. 16D, the coordinate calculation unit 45 bundles the electrodes 12 in the n-1 row and the electrodes 12 in the n row into one electrode bundle, and calculates the combined detection value T3 in the electrode bundle (step S215).

[0099] Further, as shown in FIG. 16D, the coordinate calculation unit 45 bundles the electrodes 12 in the n+1 row and the electrodes 12 in the n+2 row into one electrode bundle, and calculates the combined detection value T5 in the electrode bundle (step S216).

[0100] Then, the coordinate calculation unit 45 calculates the second data Ry2 using the combined detection value T1 in the electrode bundle formed by bundling the electrodes 12 in the n-3 row and the electrodes 12 in the n-2 row, the combined detection value T3 in the electrode bundle formed by bundling the electrodes 12 in the n-1 row and the electrodes 12 in the n row, and the combined detection value T5 in the electrode bundle formed by bundling the electrodes 12 in the n+1 row and the electrodes 12 in the n+2 row (step S217).

[0101] The coordinate calculation unit 45 obtains the difference value a between the detection value S(n) of the electrodes 12 in the n row and the detection value S(n-1) of the electrodes 12 in the n-1 row, and the difference value b between the detection value S(n) of the electrodes 12 in the n row and the detection value S(n+1) of the electrodes 12 in the n+1 row (step S218). Subsequently, the coordinate calculation unit 45 calculates the detection value ratio ps using the above formula (1) (step S219), and derives the synthesis ratio pf using the data synthesis ratio table shown in FIG. 9 (step S220).

[0102] Then, the coordinate calculation unit 45 calculates the data Ry indicating the position of the detected object F in the short side direction (second direction) on the detection area AA using the above formula (2) (step S221).

[0103] As shown in FIGS. 16A and 16B, when the object F to be detected is closest to the upper position on the n-th row of electrodes 12, the detection value S(n + 1) of the electrodes 12 on the (n + 1)-th row is larger than the detection value S(n - 1) of the electrodes 12 on the (n - 1)-th row. As a result, the difference value a between the detection value S(n) of the electrodes 12 on the n-th row and the detection value S(n - 1) of the electrodes 12 on the (n - 1)-th row is smaller than the difference value b between the detection value S(n) of the electrodes 12 on the n-th row and the detection value S(n + 1) of the electrodes 12 on the (n + 1)-th row. Therefore, by the processing from step S219 to step S221 using the above formula (1), the data composition ratio table shown in FIG. 9, and the above formula (2), the ratio of the first data Ry1 in the data Ry is larger than the ratio of the second data Ry2.

[0104] On the other hand, as shown in FIGS. 16C and 16D, when the object F to be detected is closest to the lower position on the n-th row of electrodes 12, the detection value S(n + 1) of the electrodes 12 on the (n + 1)-th row is smaller than the detection value S(n - 1) of the electrodes 12 on the (n - 1)-th row. As a result, the difference value a between the detection value S(n) of the electrodes 12 on the n-th row and the detection value S(n - 1) of the electrodes 12 on the (n - 1)-th row is larger than the difference value b between the detection value S(n) of the electrodes 12 on the n-th row and the detection value S(n + 1) of the electrodes 12 on the (n + 1)-th row. Therefore, by the processing from step S219 to step S221 using the above formula (1), the data composition ratio table shown in FIG. 9, and the above formula (2), the ratio of the first data Ry1 in the data Ry is smaller than the ratio of the second data Ry2.

[0105] Thus, in the embodiment where the width of the electrode 12 in one direction (the second direction) is narrower than the width in the other direction (the first direction) (see FIGS. 10 and 11), when the maximum detection value Smax exceeds the first threshold value Sth1 (step S002; No) and is equal to or less than the second threshold value Sth2 that is greater than the first threshold value Sth1 (step S003; Yes), two electrodes 12 arranged in the short side direction (the second direction) are bundled together to form one electrode bundle, and the combined value of the detection values of the two electrodes included in the electrode bundle is calculated as the combined detection value in the electrode bundle. Then, using the combined detection values of a plurality of electrode bundles arranged in the short side direction (the second direction), the first data Ry1 and the second data Ry2 corresponding to the position on the electrode closest to the detected object F are obtained. Further, the first data Ry1 and the second data Ry2 are combined at a ratio corresponding to the position on the electrode closest to the detected object F to calculate the data Ry indicating the position of the detected object F in the short side direction (the second direction) on the detection region AA. Thereby, the coordinate acquisition accuracy when the maximum detection value Smax exceeds the first threshold value Sth1 and is equal to or less than the second threshold value can be improved.

[0106] When the maximum detection value Smax exceeds the second threshold value Sth2 (step S003; No), the coordinate calculation unit 45 proceeds to the third process shown in FIG. 17 (step S300).

[0107] FIG. 17 is a sub - flowchart showing a specific example of the third process of the coordinate calculation process according to Embodiment 1. FIGS. 18A, 18B, 18C, and 18D are schematic diagrams for explaining the third process procedure of the coordinate calculation process according to Embodiment 1.

[0108] When shifting to the third process shown in FIG. 17, as shown in FIGS. 18A and 18C, the coordinate calculation unit 45 bundles the electrodes 12 in the n-4th row, the electrodes 12 in the n-3rd row, and the electrodes 12 in the n-2nd row into one electrode bundle, and calculates the combined detection value T2 in the electrode bundle (step S301). The combined detection value T2 in the electrode bundle formed by bundling the electrodes 12 in the n-4th row, the electrodes 12 in the n-3rd row, and the electrodes 12 in the n-2nd row is calculated as, for example, the combined value of the detection value S(n-4) of the electrodes 12 in the n-4th row, the detection value S(n-3) of the electrodes 12 in the n-3rd row, and the detection value S(n-2) of the electrodes 12 in the n-2nd row.

[0109] Also, as shown in FIGS. 18A and 18C, the coordinate calculation unit 45 bundles the electrodes 12 in the n-1st row, the electrodes 12 in the nth row, and the electrodes 12 in the n+1st row into one electrode bundle, and calculates the combined detection value T5 in the electrode bundle (step S302). The combined detection value T5 in the electrode bundle formed by bundling the electrodes 12 in the n-1st row, the electrodes 12 in the nth row, and the electrodes 12 in the n+1st row is calculated as, for example, the combined value of the detection value S(n-1) of the electrodes 12 in the n-1st row, the detection value S(n) of the electrodes 12 in the nth row, and the detection value S(n+1) of the electrodes 12 in the n+1st row.

[0110] Also, as shown in FIGS. 18A and 18C, the coordinate calculation unit 45 bundles the electrodes 12 in the n+2nd row, the electrodes 12 in the n+3rd row, and the electrodes 12 in the n+4th row into one electrode bundle, and calculates the combined detection value T8 in the electrode bundle (step S303). The combined detection value T8 in the electrode bundle formed by bundling the electrodes 12 in the n+2nd row, the electrodes 12 in the n+3rd row, and the electrodes 12 in the n+4th row is calculated as, for example, the combined value of the detection value S(n+2) of the electrodes 12 in the n+2nd row, the detection value S(n+3) of the electrodes 12 in the n+3rd row, and the detection value S(n+4) of the electrodes 12 in the n+4th row.

[0111] Then, the coordinate calculation unit 45 calculates the first data Ry1 using the combined detection value T2 in the electrode bundle formed by bundling the electrodes 12 in the n-4th row, the electrodes 12 in the n-3rd row, and the electrodes 12 in the n-2nd row, the combined detection value T5 in the electrode bundle formed by bundling the electrodes 12 in the n-1st row, the electrodes 12 in the nth row, and the electrodes 12 in the n+1st row, and the combined detection value T8 in the electrode bundle formed by bundling the electrodes 12 in the n+2nd row, the electrodes 12 in the n+3rd row, and the electrodes 12 in the n+4th row (step S304).

[0112] Subsequently, the coordinate calculation unit 45 determines whether the detection value S(n-1) of the electrodes 12 in the n-1st row is greater than or equal to the detection value S(n+1) of the electrodes 12 in the n+1st row (step S305).

[0113] As shown in FIG. 18A, when the detected object F is closest to the upper position on the electrodes 12 in the nth row, the detection value S(n-1) of the electrodes 12 in the n-1st row becomes greater than or equal to the detection value S(n+1) of the electrodes 12 in the n+1st row (step S305; Yes). In this case, as shown in FIG. 18B, the coordinate calculation unit 45 bundles the electrodes 12 in the n-5th row, the electrodes 12 in the n-4th row, and the electrodes 12 in the n-3rd row into one electrode bundle, and calculates the combined detection value T1 in the electrode bundle (step S306). The combined detection value T1 in the electrode bundle formed by bundling the electrodes 12 in the n-5th row, the electrodes 12 in the n-4th row, and the electrodes 12 in the n-3rd row is calculated as, for example, the combined value of the detection value S(n-5) of the electrodes 12 in the n-5th row, the detection value S(n-4) of the electrodes 12 in the n-4th row, and the detection value S(n-3) of the electrodes 12 in the n-3rd row.

[0114] Also, as shown in FIG. 18B, the coordinate calculation unit 45 bundles the electrodes 12 in the n-2nd row, the electrodes 12 in the n-1st row, and the electrodes 12 in the nth row into one electrode bundle, and calculates the combined detection value T4 in the electrode bundle (step S307). The combined detection value T4 in the electrode bundle formed by bundling the electrodes 12 in the n-2nd row, the electrodes 12 in the n-1st row, and the electrodes 12 in the nth row is calculated as, for example, the combined value of the detection value S(n-2) of the electrodes 12 in the n-2nd row, the detection value S(n-1) of the electrodes 12 in the n-1st row, and the detection value S(n) of the electrodes 12 in the nth row.

[0115] Further, as shown in FIG. 18B, the coordinate calculation unit 45 bundles the electrodes 12 in the n+1 row, the electrodes 12 in the n+2 row, and the electrodes 12 in the n+3 row into one electrode bundle, and calculates the combined detection value T7 in the electrode bundle (step S308). The combined detection value T7 in the electrode bundle formed by bundling the electrodes 12 in the n+1 row, the electrodes 12 in the n+2 row, and the electrodes 12 in the n+3 row is calculated as, for example, the combined value of the detection value S(n+1) of the electrodes 12 in the n+1 row, the detection value S(n+2) of the electrodes 12 in the n+2 row, and the detection value S(n+3) of the electrodes 12 in the n+3 row.

[0116] Then, the coordinate calculation unit 45 calculates the second data Ry2 using the combined detection value T1 in the electrode bundle formed by bundling the electrodes 12 in the n-5 row, the electrodes 12 in the n-4 row, and the electrodes 12 in the n-3 row, the combined detection value T4 in the electrode bundle formed by bundling the electrodes 12 in the n-2 row, the electrodes 12 in the n-1 row, and the electrodes 12 in the n row, and the combined detection value T7 in the electrode bundle formed by bundling the electrodes 12 in the n+1 row, the electrodes 12 in the n+2 row, and the electrodes 12 in the n+3 row (step S309).

[0117] As shown in FIG. 18C, when the detected object F is closest to the lower position on the electrodes 12 in the n row, the detection value S(n-1) of the electrodes 12 in the n-1 row becomes less than the detection value S(n+1) of the electrodes 12 in the n+1 row (step S305; No). In this case, as shown in FIG. 18D, the coordinate calculation unit 45 bundles the electrodes 12 in the n-3 row, the electrodes 12 in the n-2 row, and the electrodes 12 in the n-1 row into one electrode bundle, and calculates the combined detection value T3 in the electrode bundle (step S310). The combined detection value T3 in the electrode bundle formed by bundling the electrodes 12 in the n-3 row, the electrodes 12 in the n-2 row, and the electrodes 12 in the n-1 row is calculated as, for example, the combined value of the detection value S(n-3) of the electrodes 12 in the n-3 row, the detection value S(n-2) of the electrodes 12 in the n-2 row, and the detection value S(n-1) of the electrodes 12 in the n-1 row.

[0118] Also, as shown in FIG. 18D, the coordinate calculation unit 45 bundles the electrodes 12 in the n-th row, the electrodes 12 in the (n + 1)-th row, and the electrodes 12 in the (n + 2)-th row into one electrode bundle, and calculates the composite detection value T6 in the electrode bundle (step S311). The composite detection value T6 in the electrode bundle formed by bundling the electrodes 12 in the n-th row, the electrodes 12 in the (n + 1)-th row, and the electrodes 12 in the (n + 2)-th row is calculated as, for example, a composite value of the detection value S(n) of the electrodes 12 in the n-th row, the detection value S(n + 1) of the electrodes 12 in the (n + 1)-th row, and the detection value S(n + 2) of the electrodes 12 in the (n + 2)-th row.

[0119] Also, as shown in FIG. 18D, the coordinate calculation unit 45 bundles the electrodes 12 in the (n + 3)-th row, the electrodes 12 in the (n + 4)-th row, and the electrodes 12 in the (n + 5)-th row into one electrode bundle, and calculates the composite detection value T9 in the electrode bundle (step S312). The composite detection value T9 in the electrode bundle formed by bundling the electrodes 12 in the (n + 3)-th row, the electrodes 12 in the (n + 4)-th row, and the electrodes 12 in the (n + 5)-th row is calculated as, for example, a composite value of the detection value S(n + 3) of the electrodes 12 in the (n + 3)-th row, the detection value S(n + 4) of the electrodes 12 in the (n + 4)-th row, and the detection value S(n + 5) of the electrodes 12 in the (n + 5)-th row.

[0120] Then, the coordinate calculation unit 45 calculates the second data Ry2 using the composite detection value T3 in the electrode bundle formed by bundling the electrodes 12 in the (n - 3)-th row, the electrodes 12 in the (n - 2)-th row, and the electrodes 12 in the (n - 1)-th row, the composite detection value T6 in the electrode bundle formed by bundling the electrodes 12 in the n-th row, the electrodes 12 in the (n + 1)-th row, and the electrodes 12 in the (n + 2)-th row, and the composite detection value T9 in the electrode bundle formed by bundling the electrodes 12 in the (n + 3)-th row, the electrodes 12 in the (n + 4)-th row, and the electrodes 12 in the (n + 5)-th row (step S313).

[0121] The coordinate calculation unit 45 obtains the difference value a between the detection value S(n) of the electrodes 12 in the n-th row and the detection value S(n - 1) of the electrodes 12 in the (n - 1)-th row, and the difference value b between the detection value S(n) of the electrodes 12 in the n-th row and the detection value S(n + 1) of the electrodes 12 in the (n + 1)-th row (step S314). Subsequently, the coordinate calculation unit 45 calculates the detection value ratio ps using the above formula (1) (step S315), and derives the composite ratio pf using the data composite ratio table shown in FIG. 9 (step S316).

[0122] Then, the coordinate calculation unit 45 calculates data Ry indicating the position of the detected object F in the short side direction (second direction) on the detection region AA using the above equation (2) (step S317).

[0123] As shown in FIGS. 18A and 18B, when the detected object F is closest to the upper position on the n-th row of electrodes 12, the detection value S(n + 1) of the (n + 1)-th row of electrodes 12 is larger than the detection value S(n - 1) of the (n - 1)-th row of electrodes 12. Accordingly, the difference value a between the detection value S(n) of the n-th row of electrodes 12 and the detection value S(n - 1) of the (n - 1)-th row of electrodes 12 is smaller than the difference value b between the detection value S(n) of the n-th row of electrodes 12 and the detection value S(n + 1) of the (n + 1)-th row of electrodes 12. For this reason, by the processing from step S315 to step S317 using the above equation (1), the data synthesis ratio table shown in FIG. 9, and the above equation (2), the ratio of the first data Ry1 in the data Ry is larger than the ratio of the second data Ry2.

[0124] On the other hand, as shown in FIGS. 18C and 18D, when the detected object F is closest to the lower position on the n-th row of electrodes 12, the detection value S(n + 1) of the (n + 1)-th row of electrodes 12 is smaller than the detection value S(n - 1) of the (n - 1)-th row of electrodes 12. Accordingly, the difference value a between the detection value S(n) of the n-th row of electrodes 12 and the detection value S(n - 1) of the (n - 1)-th row of electrodes 12 is larger than the difference value b between the detection value S(n) of the n-th row of electrodes 12 and the detection value S(n + 1) of the (n + 1)-th row of electrodes 12. For this reason, by the processing from step S315 to step S317 using the above equation (1), the data synthesis ratio table shown in FIG. 9, and the above equation (2), the ratio of the first data Ry1 in the data Ry is smaller than the ratio of the second data Ry2.

[0125] Thus, in the embodiment where the width of the electrode 12 in one direction (the second direction) is narrower than the width in the other direction (the first direction) (see FIGS. 10 and 11), when the maximum detection value Smax exceeds the first threshold value Sth1 (step S003; No), three electrodes 12 arranged in the short side direction (the second direction) are bundled into one electrode bundle, and the combined value of the detection values of the three electrodes included in the electrode bundle is calculated as the combined detection value in the electrode bundle. Then, using the combined detection values of a plurality of electrode bundles arranged in the short side direction (the second direction), the first data Ry1 and the second data Ry2 corresponding to the position on the electrode closest to the detected object F are acquired. Further, the first data Ry1 and the second data Ry2 are combined at a ratio corresponding to the position on the electrode closest to the detected object F, and data Ry indicating the position of the detected object F in the short side direction (the second direction) on the detection region AA is calculated. Thereby, the coordinate acquisition accuracy when the maximum detection value Smax exceeds the second threshold value Sth2 can be improved.

[0126] (Modification example) FIG. 19 is a schematic diagram showing the positional relationship of a plurality of electrodes when acquiring the first data and the second data in the first processing procedure of the coordinate calculation process according to the modification example of Embodiment 1. FIG. 20 is a schematic diagram showing the positional relationship of a plurality of electrode bundles when acquiring the first data and the second data in the second processing procedure of the coordinate calculation process according to the modification example of Embodiment 1. FIG. 21 is a schematic diagram showing the positional relationship of a plurality of electrode bundles when acquiring the first data and the second data in the third processing procedure of the coordinate calculation process according to the modification example of Embodiment 1.

[0127] In the coordinate calculation process according to the above-described Embodiment 1, an aspect of acquiring the first data and the second data when the maximum detection value Smax is less than or equal to the first threshold value Sth1 using the detection values of adjacent electrodes 12 has been exemplified. However, as shown in FIG. 19, the electrodes 12 when acquiring the first data and the second data may be in a separated state from each other.

[0128] In the coordinate calculation process according to the above-described Embodiment 1, an example of obtaining the first data and the second data when the maximum detection value Smax exceeds the first threshold value Sth1 and is equal to or less than the second threshold value Sth2 greater than the first threshold value Sth1 using the combined detection values of adjacent electrode bundles has been illustrated. However, as shown in FIG. 20, the electrode bundles when obtaining the first data and the second data may be separated from each other.

[0129] In the coordinate calculation process according to the above-described Embodiment 1, an example of obtaining the first data and the second data when the maximum detection value Smax exceeds the second threshold value Sth2 using the combined detection values of adjacent electrode bundles has been illustrated. However, as shown in FIG. 21, the electrode bundles when obtaining the first data and the second data may be separated from each other.

[0130] (Embodiment 2) In Embodiment 1, an example of switching the first process, the second process, and the third process according to the magnitude of the maximum detection value Smax has been described. In this case, it is conceivable that a positional deviation of the obtained coordinates occurs before and after the switching between the first process and the second process, or before and after the switching between the second process and the third process.

[0131] In Embodiment 2, the first process, the second process, and the third process are executed regardless of the magnitude of the maximum detection value Smax, and an example of synthesizing the data calculated by the first process, the second process, and the third process according to the magnitude of the maximum detection value Smax will be described.

[0132] FIG. 22 is a flowchart showing a specific example of the coordinate calculation process according to Embodiment 2. In the coordinate calculation process according to Embodiment 2, the coordinate calculation unit 45 extracts the electrode 12 with the maximum detection value S(m,n), and detects the detection value S(m,n) of the electrode 12 as the maximum detection value Smax (step S001). Here, the detection value S(m,n) of the electrode 12 in the m-th column and n-th row detected as the maximum detection value Smax is referred to as "S(n)".

[0133] The coordinate calculation unit 45 executes the first process (step S100), the second process (step S200), and the third process (step S300) respectively, and calculates data Ry indicating the position of the detected object F in the short side direction (second direction) on the detection area AA. In the second embodiment, since the modes of the first process, the second process, and the third process are the same as those in the first embodiment, detailed description thereof is omitted here.

[0134] Also, the coordinate calculation unit 45 derives the synthesis ratios a, b, c used for calculating the data Ry indicating the position of the detected object F in the short side direction (second direction) on the detection area AA (step S004). FIG. 23A is a diagram showing an example of the first data ratio table. FIG. 23B is a diagram showing an example of the second data ratio table. FIG. 23C is a diagram showing an example of the third data ratio table. Each data ratio table shown in FIGS. 23A, 23B, and 23C may be, for example, a mode in which the synthesis ratios a, b, c are set corresponding to the maximum detection value Smax, or a mode in which a relational expression between the maximum detection value Smax and the synthesis ratios a, b, c is set. Each data ratio table is stored, for example, in the storage unit 46 provided in the processing circuit 23.

[0135] Specifically, the coordinate calculation unit 45 uses the first data ratio table shown in FIG. 23A to derive the synthesis ratio a of the data Ry that is the first processing result, and multiplies the data Ry that is the first processing result by the synthesis ratio a to calculate the first data Ry1 (step S005).

[0136] Also, the coordinate calculation unit 45 uses the second data ratio table shown in FIG. 23B to derive the synthesis ratio b of the data Ry that is the second processing result, and multiplies the data Ry that is the second processing result by the synthesis ratio b to calculate the second data Ry2 (step S006).

[0137] Also, the coordinate calculation unit 45 uses the third data ratio table shown in FIG. 23C to derive the synthesis ratio c of the data Ry that is the third processing result, and multiplies the data Ry that is the third processing result by the synthesis ratio c to calculate the third data Ry3 (step S007).

[0138] Note that the first data Ry1 and the second data Ry2 in step S005 and step S006 are different from the first data Ry1 and the second data Ry2 in each internal process of the first process, the second process, and the third process.

[0139] Then, the coordinate calculation unit 45 calculates data Ry indicating the position of the detected object F in the short side direction (second direction) on the detection region AA using the following formula (3) (step S008).

[0140] Ry = Ry1 + Ry2 + Ry3 ··· (3)

[0141] In the examples shown in FIGS. 23A, 23B, and 23C, in the first region below the first threshold value Sth1, the ratio (synthesis ratio a) of the first processing result in the data Ry is 100%. Also, in the second region exceeding the first threshold value Sth1 and below the second threshold value Sth2 greater than the first threshold value Sth1, the ratio (synthesis ratio a) of the first processing result gradually decreases, and as the ratio (synthesis ratio a) of the first processing result decreases, the ratio (synthesis ratio b) of the second processing result gradually increases. The relationship between the synthesis ratio a and the synthesis ratio b in this second region is shown by the following formula (4).

[0142] b = 1 - a ··· (4)

[0143] Note that the first threshold value Sth1 and the second threshold value Sth2 in FIGS. 23A, 23B, and 23C are different from the first threshold value Sth1 and the second threshold value Sth2 set as the threshold values for the maximum detection value Smax in Embodiment 1.

[0144] Also, in the examples shown in FIGS. 23A, 23B, and 23C, in the third region that exceeds the second threshold value Sth2 and is equal to or less than the third threshold value Sth3 that is greater than the second threshold value Sth2, the ratio (synthesis ratio b) of the second processing result in the data Ry becomes 100%. Further, in the fourth region that exceeds the third threshold value Sth3 and is equal to or less than the fourth threshold value Sth4 that is greater than the third threshold value Sth31, the ratio (synthesis ratio b) of the second processing result gradually decreases, and as the ratio (synthesis ratio b) of the second processing result decreases, the ratio (synthesis ratio c) of the third processing result gradually increases. The relationship between the synthesis ratio b and the synthesis ratio c in this fourth region is represented by the following formula (5). And in the fifth region that exceeds the fourth threshold value Sth4, the ratio (synthesis ratio c) of the third processing result in the data Ry becomes 100%.

[0145] c = 1 - b ··· (5)

[0146] Thereby, when the maximum detection value Smax transitions between regions, it is possible to suppress a large change in the data Ry indicating the position of the detected object F in the short side direction (second direction) on the detection region AA.

[0147] In the coordinate calculation process according to the second embodiment, as described above, the first processing result, the second processing result, and the third processing result are synthesized at a ratio according to the magnitude of the maximum detection value Smax, and the data Ry indicating the position of the detected object F in the short side direction (second direction) on the detection region AA is calculated. Thereby, the coordinate acquisition accuracy can be improved regardless of the magnitude of the maximum detection value Smax.

[0148] In addition, in the second embodiment described above, an example in which the first processing, the second processing, and the third processing are executed regardless of the magnitude of the maximum detection value Smax has been described. However, for example, in the first region and the second region where the maximum detection value Smax is equal to or less than the second threshold value Sth2, a mode in which the third processing is not executed may be employed. Further, for example, in the fourth region and the fifth region where the maximum detection value Smax exceeds the third threshold value Sth3, a mode in which the first processing is not executed may be employed. Furthermore, in the fifth region where the maximum detection value Smax clearly exceeds the fourth threshold value Sth4, a mode in which the second processing is not executed in addition to the first processing may be employed.

[0149] The preferred embodiments of the present disclosure have been described above, but the present disclosure is not limited to such embodiments. The content disclosed in the embodiments is merely an example, and various modifications are possible without departing from the spirit of the present disclosure. Appropriate modifications made without departing from the spirit of the present disclosure also naturally belong to the technical scope of the present disclosure.

Description of Reference Numerals

[0150] 1 Detection device 10 Sensor unit 11 Sensor substrate 12 Electrode 13 Wiring 14 Shield 15 Cover glass 20 Control unit 21 Control substrate 22 Detection circuit 23 Processing circuit 24 Power supply circuit 25 Interface circuit 31 Wiring substrate 40 Detection unit 42 Signal detection unit 43 A / D conversion unit 44 Signal processing unit 45 Coordinate calculation unit 46 Memory unit 200 Display panel AA Detection area AG Air gap D, D(m,n) Distance DA Display area Det(m,n) Detection signal F Detected object OC Adhesive layer Rawdata, Rawdata(m,n) Output value S, S(m,n) Detection value T1, T2, T3, T4, T5, T6, T7, T8, T9 Composite detection value

Claims

1. A detection region provided with a plurality of electrodes arranged in a first direction and a second direction different from the first direction; A signal processing unit that generates a detection value for each of the electrodes; A coordinate calculation unit that calculates data indicating the position of a detection object on the detection region in the second direction based on the detection values of the plurality of electrodes arranged in the second direction; Comprising: The shapes of the plurality of electrodes are rectangular shapes in which the width in the second direction is smaller than the width in the first direction. A detection device.

2. The coordinate calculation unit: Extracts the electrode with the maximum detection value and sets the detection value of the electrode as the maximum detection value, calculates the data using the detection values of at least three electrodes including the electrode extracted as the maximum detection value, and changes the number of electrodes used for calculating the data according to the magnitude of the maximum detection value. The detection device according to claim 1.

3. The coordinate calculation unit: When the maximum detection value is equal to or less than a predetermined threshold value, calculates the data using the detection values of three electrodes; When the maximum detection value exceeds the threshold value, obtains a combined detection value of the detection values of the plurality of electrodes arranged in the second direction, and calculates the data using three combined detection values. The detection device according to claim 2.

4. A first threshold value and a second threshold value greater than the first threshold value are set as the threshold value for the maximum detection value. The coordinate calculation unit: When the maximum detection value is equal to or less than the first threshold value, calculates the data using the detection values of three electrodes; When the maximum detection value exceeds the first threshold value and the maximum detection value is equal to or less than the second threshold value, obtains a combined detection value of the detection values of two electrodes arranged in the second direction, and calculates the data using three combined detection values; When the maximum detection value exceeds the second threshold value, obtains a combined detection value of the detection values of three electrodes arranged in the second direction, and calculates the data using three combined detection values. The detection device according to claim 2.

5. The coordinate calculation unit: Obtains the result calculated using the detection values of three electrodes, the combined detection value of the detection values of two electrodes arranged in the second direction, the combined detection value of the detection values of three electrodes arranged in the second direction, and the result calculated using three combined detection values, and synthesizes them at a ratio corresponding to the magnitude of the maximum detection value to calculate the data. The detection device according to claim 2.

6. A sensor substrate provided with a plurality of the electrodes; A cover glass that overlaps in a third direction orthogonal to the first direction and the second direction via an adhesive layer with the sensor substrate; comprising; The detection device according to any one of claims 1 to 5.

7. The detection device according to claim 6, and; A display panel disposed opposite to the sensor substrate with an air gap therebetween; comprising; In a plan view, the detection area and the display area of the display panel overlap in the third direction; A detection system.

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