Input device and output detection method for input device

Abstract

Provided are: an input device capable of accurately detecting the operation amount of a pressing operation; and an output detection method for the input device.　An input device (100) which comprises a skin-like cover (104) having an operation surface (104a), a first electrode (110) positioned on the rear side of the operation surface, a plurality of second electrodes (120) positioned so as to face the first electrode, an elastic member (102) positioned between the skin-like cover and the plurality of second electrodes, and a control unit (160) connected to the plurality of second electrodes, wherein: the skin-like cover and the elastic member are capable of elastic deformation as a result of a pressing operation on the operation surface of the operating body (FT); the control unit selects one or more second electrodes from among the plurality of second electrodes as drive electrodes (120Tx), and selects one or more second electrodes which are adjacent to the second electrodes selected as drive electrodes from among the plurality of second electrodes as detection electrodes (120Rx); the combination of second electrodes which are selected as drive electrodes and detection electrodes from among the plurality of second electrodes is switched; and the detection electrode output is detected for the plurality of combinations.

Description

[Technical Field]

[0001] The present disclosure relates to an input device and an output detection method in an input device. [Background technology]

[0002] Conventionally, there has been a capacitance-type pressure sensor that includes a first electrode sheet having a first electrode layer formed on a first insulating sheet, a second electrode sheet having a second electrode layer formed on a second insulating sheet, an elastic layer sandwiched between the first electrode sheet and the second electrode sheet, and adhesive layers formed on the surface of the elastic layer facing the first electrode sheet and the surface facing the second electrode sheet, respectively, and that detects a pressing force based on a change in capacitance between the first electrode layer and the second electrode layer in response to a change in distance between the first electrode layer and the second electrode layer when the first electrode sheet or the second electrode sheet is pressed (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7091429 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in a conventional capacitance-type pressure sensor, the amount of change in capacitance between the first electrode layer and the second electrode layer may vary significantly depending on the position of the pressing operation, because the planar positional relationship between the position of the pressing operation and the first and second electrode layers may change depending on the position of the pressing operation. If the amount of change in capacitance detected varies significantly depending on the position of the pressing operation, the accuracy of detecting the amount of pressing operation may decrease.

[0005] Therefore, an object of the present invention is to provide an input device that can detect the amount of pressing operation with high accuracy, and an output detection method for the input device. [Means for solving the problem]

[0006] An input device according to an embodiment of the present disclosure includes a skin having an operation surface, a first electrode arranged on the back side of the operation surface, a plurality of second electrodes arranged opposite the first electrode, an elastic member arranged between the skin and the plurality of second electrodes, and a control unit connected to the plurality of second electrodes, wherein the skin and the elastic member are elastically deformable by a pressing operation of an operating body against the operation surface, and the control unit selects at least one second electrode from the plurality of second electrodes as a drive electrode, selects at least one second electrode from the plurality of second electrodes adjacent to the second electrode selected as the drive electrode as a detection electrode, switches combinations of second electrodes selected as the drive electrode and the detection electrode from the plurality of second electrodes, and detects outputs of the detection electrodes in the plurality of combinations.

[0007] An output detection method for an input device according to an embodiment of the present disclosure is an output detection method for an input device including a skin having an operation surface, a first electrode arranged on the back side of the operation surface, a plurality of second electrodes arranged opposite the first electrode, an elastic member arranged between the skin and the plurality of second electrodes, and a control unit connected to the plurality of second electrodes, wherein the skin and the elastic member are elastically deformable by a pressing operation of an operating body against the operation surface, and the control unit selects at least one second electrode from the plurality of second electrodes as a drive electrode, selects at least one second electrode from the plurality of second electrodes adjacent to the second electrode selected as the drive electrode as a detection electrode, switches combinations of second electrodes selected as the drive electrode and the detection electrode from the plurality of second electrodes, and detects outputs of the detection electrodes in the plurality of combinations. [Effects of the Invention]

[0008] It is possible to provide an input device that can detect the amount of pressing operation with high accuracy, and an output detection method for the input device. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view illustrating an example of a configuration of an input device according to an embodiment. [Figure 2] FIG. 10 is a diagram illustrating an example of a state in which a pressing operation is performed on the input device according to the embodiment. [Figure 3A] FIG. 2 is a diagram showing an example of a planar configuration of a plurality of electrodes. [Figure 3B] FIG. 10 is a diagram showing an example of a combination of selected drive electrodes and detection electrodes. [Figure 3C] FIG. 10 is a diagram showing an example of combinations of selected drive electrodes and detection electrodes after changing the combination eight times. [Figure 4] 10A and 10B are diagrams illustrating an example of the relationship between a pressing force when a pressing operation is performed and a capacitance detected by a detection unit. [Figure 5A] FIG. 10 is a diagram showing an example of a combination of selected drive electrodes and detection electrodes according to a first modified example of the embodiment. [Figure 5B] FIG. 10 is a diagram showing an example of a combination of selected drive electrodes and detection electrodes according to a second modified example of the embodiment. [Figure 6A] FIG. 10 is a cross-sectional view showing an example of the configuration of an input device according to a third modified example of the embodiment. [Figure 6B] 11 is a diagram showing an example of the relationship between a pressing force and a capacitance detected by a detection unit when a pressing operation is performed in an input device according to a third modified example of the embodiment. FIG. [Figure 7A] FIG. 10 is a diagram showing an example of a combination of selected drive electrodes and detection electrodes according to a fourth modified example of the embodiment. [Figure 7B] FIG. 13 is a diagram showing an example of a configuration in which the electrode of the fourth modified example is further modified. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment to which the input device and the output detection method for the input device according to the present disclosure are applied will be described.

[0011] <Embodiment> In the following description, the XYZ coordinate system is defined. The direction parallel to the X axis (X direction), the direction parallel to the Y axis (Y direction), and the direction parallel to the Z axis (Z direction) are perpendicular to one another. For ease of explanation, the -Z direction may be referred to as the lower side or bottom, and the +Z direction as the upper side or top, but this does not represent a universal vertical relationship. Furthermore, a planar view refers to a view on an XY plane.

[0012] In the following description, the length, width, thickness, etc. of each part may be exaggerated to make the configuration easier to understand. Furthermore, terms such as parallel, up and down, etc. may be misaligned to the extent that the effect of the embodiment is not impaired.

[0013] <Embodiment> FIG. 1 is a cross-sectional view showing an example of the configuration of an input device 100 according to an embodiment.

[0014] <Configuration of input device 100> The input device 100 includes a substrate 101, a foam layer 102, a skin 104, a floating electrode 110, a plurality of electrodes 120, a driving electrode 120Tx, a detecting electrode 120Rx, a power supply 130, a multiplexer 140, a detecting unit 150, and an MCU (Micro Controller Unit) 160. The foam layer 102 is an example of an elastic member that can be deformed by a pressing operation by an operator. The upper surface of the skin 104 is an operation surface 104A of the input device 100. The floating electrode 110 is an example of a first electrode. The plurality of electrodes 120 are an example of a plurality of second electrodes, and the driving electrode 120Tx and the detecting electrode 120Rx are selected from the plurality of electrodes 120. For this reason, the driving electrode 120Tx and the detecting electrode 120Rx are denoted by the reference numeral 120 in parentheses. The MCU 160 is an example of a control unit.

[0015] The input device 100 selects electrodes 120 to be used as drive electrodes 120Tx and detection electrodes 120Rx from among a plurality of electrodes 120 provided on the upper surface of the substrate 101. Such a configuration will be described later with reference to Figures 3A and 3B, etc.

[0016] The input device 100 is a device that determines whether a fingertip FT, as an example of an operating object, has performed an operation of proximity, touch, or pressure on the operating surface 104A of the input device 100. The input device 100 determines the presence or absence of an operation using a mutual capacitance method based on the electrostatic capacitance (mutual capacitance) between the drive electrodes 120Tx and the detection electrodes 120Rx. Hereinafter, an operation by proximity, touch, or pressure may be referred to as a proximity operation, a touch operation, or a pressure operation. Furthermore, the operating object is not limited to the fingertip FT.

[0017] The pressing operation is an operation in which the fingertip FT presses the operation surface 104A downward. The touch operation is an operation in which the fingertip FT touches the operation surface 104A but does not press downward. The proximity operation is an operation in which the fingertip FT does not touch the operation surface 104A but brings the fingertip FT close to the operation surface 104A so that the capacitance between the drive electrode 120Tx and the detection electrode 120Rx becomes large to a certain extent.

[0018] Furthermore, when a proximity operation, a touch operation, or a pressure operation is performed on the operation surface 104A, the capacitance between the drive electrodes 120Tx and the detection electrodes 120Rx increases in the order of the proximity operation, the touch operation, and the pressure operation. Therefore, the input device 100 can distinguish between the proximity operation, the touch operation, and the pressure operation by using a capacitance threshold value for distinguishing between the proximity operation, the touch operation, and the pressure operation.

[0019] In the following, a method for distinguishing between a proximity operation and a touch operation will be omitted, and the input device 100 capable of detecting the amount of a pressing operation with high accuracy and an output detection method in the input device will be mainly described.

[0020] In the following, the capacitance between the fingertip FT and the floating electrode 110 is defined as Cfg, the capacitance between the floating electrode 110 and the driving electrode 120Tx is defined as Ctf, the capacitance between the floating electrode 110 and the detection electrode 120Rx is defined as Crf, and the capacitance between the driving electrode 120Tx and the detection electrode 120Rx is defined as Crt.

[0021] <Substrate 101> The substrate 101 is provided at the bottom of the input device 100. The substrate 101 is, for example, a wiring substrate. On the top surface of the substrate 101, a driving electrode 120Tx and a detecting electrode 120Rx are provided.

[0022] <Foam layer 102> The foam layer 102 has a depth (width) in the Y direction and, for example, is rectangular in plan view. The foam layer 102 is disposed on the upper surface of the substrate 101. The driving electrodes 120Tx and the detecting electrodes 120Rx are sandwiched between the upper surface of the substrate 101 and the foam layer 102.

[0023] For example, the foam layer 102 has a shape in which the top surface and four side surfaces are continuously curved. The foam layer 102 can be made of a foam material such as foamed urethane, foamed sponge, or foamed rubber, and has cushioning properties. The foam layer 102 is provided on the substrate 101, and the top surface and all four side surfaces are covered with a skin 104.

[0024] The foam layer 102 is configured to be thicker than the skin 104. This is because making the material that is more easily elastically deformed than the skin 104 thicker improves the tactile sensation sensed by the fingertip FT during a pressing operation. Also, when detecting a pressing operation using the floating electrode 110, the driving electrode 120Tx, and the detecting electrode 120Rx, the floating electrode 110 is spaced apart from the driving electrode 120Tx and the detecting electrode 120Rx to some extent, making detection easier.

[0025] <Eidermis 104> The skin 104 is a cloth-like cover made of resin, synthetic fiber, synthetic leather, leather, or the like, and is configured to cover the entire outer surface of the foam layer 102 and to easily change shape to fit the shape of the outer surface of the foam layer 102.

[0026] The skin 104 has an operation surface 104A. The operation surface 104A is the upper surface of the skin 104 and is a decorative layer exposed to the operator. A floating electrode 110 is provided in the center of the lower surface of the skin 104 in a plan view. The operation surface 104A is at least a portion of the outer surface of the skin 104 that overlaps with the floating electrode 110.

[0027] Furthermore, the skin 104, together with the floating electrode 110, may be formed of a transparent material. Transparency refers to the property of transmitting visible light, and the degree of transparency may be set as desired. In this case, the skin 104 and the floating electrode 110 may be transparent, allowing the foam layer 102 to be seen. For example, the skin 104 may be illuminated by providing a light source on the upper surface of the substrate 101, or a decorative layer may be provided on the lower surface of the skin 104.

[0028] For example, the skin 104 is folded back to the lower surface of the substrate 101 while covering the upper and side surfaces of the foam layer 102, and is fixed to the lower surface of the substrate 101. In this state, the floating electrode 110 abuts against the outer surface of the foam layer 102.

[0029] Although the embodiment in which the skin 104 is a cloth-like cover that covers the entire outer surface of the foam layer 102 will be described here, the skin 104 may also be a bag-like cover. Furthermore, the skin 104 may be configured to cover at least the upper surface of the foam layer 102, and may, for example, be configured to cover only the upper surface of the foam layer 102, or to cover the upper surface and side surfaces of the foam layer 102, etc.

[0030] <Floating electrode 110> The floating electrode 110 is provided in the center of the lower surface of the skin 104 in a plan view. The floating electrode 110 is formed, for example, by printing silver paste or the like on the lower surface of the skin 104. The floating electrode 110 is electrically floating. The floating electrode 110 faces the driving electrode 120Tx and the detecting electrode 120Rx and is electromagnetically coupled to the driving electrode 120Tx and the detecting electrode 120Rx. Note that the floating electrode 110 may be formed by evaporation deposition on the lower surface of the skin 104, rather than by printing.

[0031] The floating electrode 110 is provided to mitigate fluctuations in the output of the detection electrode 120Rx depending on the position of the pressing operation. By providing the floating electrode 110, which is electromagnetically coupled to the drive electrode 120Tx and the detection electrode 120Rx, closer to the operation surface 104A than the drive electrode 120Tx and the detection electrode 120Rx, fluctuations in the output of the detection electrode 120Rx depending on the position of the pressing operation can be mitigated compared to when the floating electrode 110 is not present. For this reason, the floating electrode 110 preferably has the same size as the multiple electrodes 120 in a planar view, but may be smaller or larger than the multiple electrodes 120. Note that when the skin 104 is made of a transparent material, the floating electrode 110 may also be made of a transparent material.

[0032] <Multiple electrodes 120> The plurality of electrodes 120 are provided in the center of the upper surface of the substrate 101, and face the floating electrode 110. The plurality of electrodes 120 are made of copper foil, for example, and are formed by patterning the copper foil or the like provided on the upper surface of the substrate 101.

[0033] The multiple electrodes 120 are connected to the multiplexer 140 via wiring on the substrate 101 or wiring provided outside the substrate 101. At least one of the multiple electrodes 120 is selected as a drive electrode 120Tx, and at least one electrode 120 adjacent to the drive electrode 120Tx is selected as a detection electrode 120Rx. There may be multiple drive electrodes 120Tx.

[0034] <Drive electrode 120Tx> The driving electrode 120Tx is provided in the center of the upper surface of the substrate 101, and faces the floating electrode 110. The driving electrode 120Tx is connected to a power supply 130 via a multiplexer 140.

[0035] <Detection electrode 120Rx> The detection electrode 120Rx is provided in the center of the upper surface of the substrate 101, and faces the floating electrode 110. The detection electrode 120Rx is connected to the detection unit 150 via the multiplexer 140.

[0036] The driving electrodes 120Tx and the detecting electrodes 120Rx are selected from a plurality of electrodes 120 provided on the upper surface of the substrate 101, and therefore, the electrodes 120 selected as the driving electrodes 120Tx and the electrodes 120 selected as the detecting electrodes 120Rx are switched in a time-division manner among the plurality of electrodes 120. Details of this will be described later with reference to Figures 3A to 3C, etc.

[0037] <Power supply 130> The power supply 130 is connected between the multiplexer 140 and the MCU 160, and when driven by the control unit 161 of the MCU 160, outputs an AC drive voltage to the multiplexer 140. The AC drive voltage is supplied to the drive electrodes 120Tx via the multiplexer 140. The power supply 130 may be any AC power supply that is capable of outputting an AC drive voltage.

[0038] <Multiplexer 140> The multiplexer 140 is connected between the drive electrodes 120Tx and the detection electrodes 120Rx and the power supply 130 and the detection unit 150.

[0039] The driving electrodes 120Tx and the detecting electrodes 120Rx are selected from a plurality of electrodes 120 provided on the upper surface of the substrate 101. The electrodes 120 selected as the driving electrodes 120Tx and the electrodes 120 selected as the detecting electrodes 120Rx are switched in a time-division manner. For this reason, a multiplexer 140 is provided between the driving electrodes 120Tx and the detecting electrodes 120Rx and the power supply 130 and the detecting unit 150.

[0040] The multiplexer 140 switches the connection state in response to a switching signal input from the control unit 161 of the MCU 160 so as to connect the drive electrodes 120Tx and the power supply 130 and also connect the detection electrodes 120Rx and the detection unit 150.

[0041] When the determination unit 162 of the MCU 160 determines whether or not the fingertip FT is being operated, the power source 130 applies an AC drive voltage to the drive electrode 120Tx, and therefore the multiplexer 140 connects the selected drive electrode 120Tx to the power source 130 in accordance with the switching signal.

[0042] Furthermore, when the judgment unit 162 of the MCU 160 judges whether or not the fingertip FT is being operated, the detection unit 150 detects the output of the detection electrode 120Rx, and therefore the multiplexer 140 connects the selected detection electrode 120Rx to the detection unit 150 in accordance with the switching signal.

[0043] <Detection unit 150> The detection unit 150 is connected to the detection electrodes 120Rx via the multiplexer 140, detects the current flowing through the detection electrodes 120Rx, and detects the capacitance by integrating the current. The detection unit 150 converts the detected capacitance into a digital value and outputs it. The detection unit 150 functions as an AD (Analog to Digital) converter. The detection unit 150 outputs the digitally converted capacitance to the MCU 160.

[0044] <mcu160> The MCU 160 includes a control unit 161, a determination unit 162, and a memory 163. The MCU 160 is realized by a computer including a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), an input / output interface, an internal bus, and the like.

[0045] The control unit 161 and the determination unit 162 are functional blocks showing the functions of the program executed by the MCU 160. The memory 163 is a functional representation of the memory of the MCU 160.

[0046] The control unit 161 is a processing unit that controls the operation of the MCU 160, and performs, for example, driving the power supply 130 and other processes.

[0047] The control unit 161 drives the power supply 130 while selecting the drive electrodes 120Tx and the detection electrodes 120Rx, and outputs a switching signal to the multiplexer 140. In this way, the drive electrodes 120Tx and the detection electrodes 120Rx are selected from the plurality of electrodes 120, an AC drive voltage is supplied from the power supply 130 to the drive electrodes 120Tx via the multiplexer 140, and the output of the detection electrodes 120Rx is detected by the detection unit 150 via the multiplexer 140.

[0048] The determination unit 162 determines whether or not an operation has been performed based on the output (capacitance) of the detection unit 150. The determination unit 162 can determine, for example, which of the operations performed is proximity, touch, or pressure.

[0049] The memory 163 stores programs, data, etc. required for the control unit 161 and the determination unit 162 to execute the processes.

[0050] <Operation of input device 100> FIG. 2 is a diagram illustrating an example of a state in which a pressing operation is being performed on the input device 100. When the center of the surface 104 is pressed downward with the fingertip FT, the surface 104, the driving electrodes 120Tx, and the foam layer 102 bend as shown in FIG. 2, and the distance between the floating electrode 110 and the driving electrodes 120Tx and the detecting electrodes 120Rx becomes shorter. In this state, the determination unit 162 determines that a pressing operation is being performed. Furthermore, when the fingertip FT is in contact with the operation surface 104A but is not pressing downward, the determination unit 162 determines that a touch operation is being performed. Furthermore, when the fingertip FT is not in contact with the operation surface 104A but is in proximity thereto, and the capacitance between the driving electrodes 120Tx and the detecting electrodes 120Rx becomes somewhat large, the determination unit 162 determines that a proximity operation is being performed.

[0051] <Configuration of Multiple Electrodes 120> 3A is a diagram showing an example of a planar configuration of the plurality of electrodes 120. The plurality of electrodes 120 are provided in the center of the upper surface of the substrate 101, for example.

[0052] The plurality of electrodes 120 are circular as a whole, and have a shape obtained by dividing a circle into eight equal parts with respect to the center. That is, each electrode 120 has a sector shape with a central angle of 45 degrees in a planar view. In this way, the plurality of electrodes 120 are preferably divided into N equal parts in a planar view, where N is the number of divisions (N is an integer of 3 or more). This is because using the plurality of electrodes 120 with equally divided shapes makes it possible to appropriately detect the operation position on operation surface 104A.

[0053] As an example, such eight electrodes 120 can be produced by dividing a copper foil patterned into a circle into eight equal parts across the center. The eight electrodes 120 are separated from one another and are not electrically connected. The boundaries 120A between adjacent electrodes 120 are linear in plan view. The boundaries 120A are an example of boundaries between adjacent second electrodes. The eight electrodes 120 have eight boundaries 120A.

[0054] Although a configuration using eight electrodes 120 obtained by dividing a circular electrode into eight equal parts will be described here, the number of electrodes 120 is not limited to eight, and the overall shape is not limited to a circle, as long as there are multiple electrodes 120 of the same size and shape. The overall shape of the multiple electrodes 120 may be an ellipse, a triangle, a rectangle, or a polygon with pentagons or more sides.

[0055] <Selection and Combination of Driving Electrodes 120Tx and Detection Electrodes 120Rx> 3B is a diagram showing an example of a combination of selections of the driving electrodes 120Tx and the detecting electrodes 120Rx. FIG. 3B shows an example of a combination of selections at times t1, t2, and t3. In FIG. 3B, the electrodes 120 selected as the driving electrodes 120Tx are indicated by dots, and the electrodes 120 selected as the detecting electrodes 120Rx are indicated by outlined parts. Note that the substrate 101 is omitted in FIG. 3B.

[0056] Here, four adjacent electrodes of the eight electrodes 120 are selected as drive electrodes 120Tx, and the remaining four adjacent electrodes are selected as detection electrodes 120Rx. The four drive electrodes 120Tx and the four detection electrodes 120Rx are both arranged in a semicircle.

[0057] An AC drive voltage is supplied to the four drive electrodes 120Tx from a power source 130 via a multiplexer 140. The four detection electrodes 120Rx are connected to a detection unit 150 via the multiplexer 140. Therefore, the detection unit 150 detects the capacitance of the four detection electrodes 120Rx.

[0058] 3B, boundaries 120B between the four drive electrodes 120Tx and the four detection electrodes 120Rx are indicated by dashed ellipses. Here, of the eight boundaries 120A of the eight electrodes 120, the boundaries between the four drive electrodes 120Tx and the four detection electrodes 120Rx are distinguished as boundaries 120B and will be described.

[0059] The boundary 120B between the driving electrode 120Tx and the detection electrode 120Rx is a portion where the capacitance Crt (see FIG. 1) is obtained. When the foam layer 102 is bent by a pressing operation at the boundary 120B, the distance between the floating electrode 110 and the driving electrode 120Tx and the detection electrode 120Rx is shortened, and the capacitances Ctf and Crf (see FIG. 1) increase. Because the capacitances Ctf and Crf increase due to a pressing operation, the boundary 120B is a portion that causes a large fluctuation in the output of the detection electrode 120Rx. In other words, the boundary 120B between the driving electrode 120Tx and the detection electrode 120Rx is the portion where the sensitivity of the output of the detection electrode 120Rx is highest among the eight electrodes 120 in a planar view. The detection unit 150 detects the capacitance Crt at the boundary 120B.

[0060] Because the boundary 120B exists on a straight line passing through the centers of the eight electrodes 120, in a planar view, the output of the detection electrodes 120Rx varies depending on the position of the pressing operation relative to the circular area in which the eight electrodes 120 are provided. Such fluctuations in the output of the detection electrodes 120Rx affect the detection of the amount of pressing operation. The fluctuations in the output of the detection electrodes 120Rx depending on the position of the pressing operation can be alleviated to some extent by providing the floating electrodes 110, but because the output of the detection electrodes 120Rx varies depending on the positional relationship between the fingertip FT and the drive electrodes 120Tx and the detection electrodes 120Rx in a planar view, mitigation by the floating electrodes 110 alone is not sufficient.

[0061] Therefore, the input device 100 of the embodiment shifts the position of the boundary 120B with high detection sensitivity in a time-division manner by, for example, shifting the combinations of four electrodes 120 selected as the four drive electrodes 120Tx and the four detection electrodes 120Rx by one at times t1, t2, and t3. The selection of the combinations of four electrodes 120 is performed by the control unit 161 of the MCU 160.

[0062] In this way, by shifting the boundary 120B between the drive electrodes 120Tx and the detection electrodes 120Rx in a time-division manner, the detection sensitivity is equalized across all eight electrodes 120. By equalizing the detection sensitivity across all eight electrodes 120, it becomes possible to detect the amount of pressing operation with high accuracy.

[0063] 3C is a diagram showing an example of the combination of the selected drive electrodes 120Tx and the detection electrodes 120Rx after changing the combination eight times. When the four electrodes 120 selected as the four drive electrodes 120Tx and the four detection electrodes 120Rx are shifted one by one eight times in succession, the four drive electrodes 120Tx and the four detection electrodes 120Rx complete one revolution, as shown in the first to eighth combinations in FIG. 3C. This is synonymous with the boundary 120B shown in FIG. 3B completing one revolution.

[0064] For example, in the above-described format, the operation amount of the pressing operation may be detected based on the output of the detection electrodes 120Rx while shifting the position of the boundary 120B between the four drive electrodes 120Tx and the four detection electrodes 120Rx. Since the operation amount of the pressing operation is the amount of pressing on the operation surface 104A, the pressing force when the operation surface 104A is pressed can be detected by detecting the output (capacitance) of the detection electrodes 120Rx.

[0065] 3C , the electrodes 120 selected as the four driving electrodes 120Tx and the four detecting electrodes 120Rx are shifted one by one around the circle, so that the determination unit 162 of the MCU 160 switches the combination of the electrodes 120 selected as the driving electrodes 120Tx and the detecting electrodes 120Rx multiple times so that each of the multiple electrodes 120 is selected as the detecting electrode 120Rx at least once. Furthermore, the multiple electrodes 120 have multiple boundaries 120A between adjacent electrodes 120. The MCU 160 switches the combination of the electrodes 120 selected as the driving electrodes 120Tx and the detecting electrodes 120Rx multiple times so that each of the multiple boundaries 120A is located between the driving electrodes 120Tx and the detecting electrodes 120Rx at least once.

[0066] <Simulation results> Fig. 4 is a diagram showing an example of the relationship between the pressing force when a pressing operation is performed on the input device 100 and the capacitance detected by the detection unit 150. Fig. 4 shows the calculation results of a simulation in which pressing operations are performed on the center part of the operation surface 104A and the peripheral part of the operation surface 104A. In the simulation, four driving electrodes 120Tx and four detecting electrodes 120Rx were selected from the eight electrodes 120 as shown in Fig. 3A, and the electrodes 120 were shifted one by one as shown in Fig. 3B, and the boundary 120B was moved at least once around the electrode 120B, thereby calculating the capacitance detected by the detection unit 150.

[0067] The central part of operation surface 104A is the central part of eight electrodes 120 in plan view, and the peripheral part of operation surface 104A is the part outside the central part within the circular region of eight electrodes 120 in plan view.

[0068] 4, the horizontal axis represents pressure (N). 0N on the horizontal axis indicates a position where the pressure is zero, representing a state in which the fingertip FT touches the operation surface 104A (a state in which a touch operation has been performed). The vertical axis represents the capacitance detected by the detection unit 150 as a count value (without units). The characteristics of a pressing operation on the center of the operation surface 104A are indicated by a solid line, and the characteristics of a pressing operation on the periphery of the operation surface 104A are indicated by a dashed line.

[0069] 4, the capacitance of the operation of pressing the center of operation surface 104A (solid line) and the capacitance of the operation of pressing the periphery of operation surface 104A (dashed line) are very similar values. Furthermore, the capacitance begins to increase at approximately 2.5 N. A pressing force of 2.5 N is a relatively weak force required, for example, when operating a button on an electronic device, and is an appropriate value as the operating load for an operating unit of an electronic device installed in the passenger compartment of a vehicle.

[0070] In the characteristics shown in Figure 4, the capacitance count value is negative when the pressing force is approximately 4N or less. However, by detecting the self-capacitance of the detection electrode 120Rx and correcting the mutual capacitance between the drive electrode 120Tx and the detection electrode 120Rx based on the self-capacitance, it is possible to make the capacitance count value approximately zero when the pressing force is 0N.

[0071] As described above, it was found that the capacitance of the pressing operation (solid line) on the center of the operation surface 104A and the capacitance of the pressing operation (dashed line) on the periphery of the operation surface 104A show very similar values. This confirmed that the input device 100 of the embodiment can detect the amount of the pressing operation with high accuracy regardless of the position where the pressing operation is performed on the operation surface 104A.

[0072] <Effects> The input device 100 includes a skin 104 having an operation surface 104A, a first electrode (floating electrode 110) arranged on the back side of the operation surface 104A, a plurality of electrodes 120 arranged opposite to the first electrode (floating electrode 110), a foam layer 102 arranged between the skin 104 and the plurality of electrodes 120, and an MCU 160 connected to the plurality of electrodes 120, and the skin 104 and the foam layer 102 are elastically deformable by a pressing operation of a fingertip FT against the operation surface 104A, and the MCU 160 is 60 selects at least one electrode 120 from the plurality of electrodes 120 as a driving electrode 120Tx, selects at least one electrode 120 from the plurality of electrodes 120 adjacent to the electrode 120 selected as the driving electrode 120Tx as a detection electrode 120Rx, switches the combination of electrodes 120 selected from the plurality of electrodes 120 as the driving electrode 120Tx and the detection electrode 120Rx, and detects the output of the detection electrode 120Rx in the plurality of combinations.

[0073] Therefore, by detecting the output of the detection electrode 120Rx in multiple combinations of electrodes 120 selected as the driving electrode 120Tx and the detection electrode 120Rx, the output of the detection electrode 120Rx is equalized regardless of the position of the pressing operation on the first electrode (floating electrode 110) and the driving electrode 120Tx and the detection electrode 120Rx.

[0074] Therefore, it is possible to provide the input device 100 that can detect the amount of pressing operation with high accuracy.

[0075] In order to equalize the output of the detection electrodes 120Rx regardless of the position of the pressing operation, in addition to the method of switching the combination of electrodes 120 selected as the driving electrodes 120Tx and the detection electrodes 120Rx as described above, a method is also conceivable in which the driving electrodes 120Tx and the detection electrodes 120Rx have interdigitated shapes in a planar view and the above-described switching of the combination is not performed. Even when the driving electrodes 120Tx and the detection electrodes 120Rx have interdigitated shapes in a planar view, it is possible to suppress unevenness in the output of the detection electrodes 120Rx depending on the position of the pressing operation. However, when the driving electrodes 120Tx and the detection electrodes 120Rx have interdigitated shapes in a planar view, the electrostatic capacitance (mutual capacitance) does not change sufficiently with changes in the amount of pressing operation, making it difficult to detect the amount of pressing operation. This phenomenon occurs both when the central portion of the operation surface 104A is pressed and when the peripheral portion of the operation surface 104A is pressed.

[0076] In contrast, the input device 100 of the embodiment has a simple configuration of the electrodes 120, which reduces manufacturing costs, and by switching the combination of electrodes 120 selected as the drive electrodes 120Tx and the detection electrodes 120Rx, it is possible to equalize the outputs of the detection electrodes 120Rx regardless of the position of the pressing operation. As a result, it is possible to provide the input device 100 that can detect the amount of pressing operation with high accuracy.

[0077] Since the first electrode (floating electrode 110) is the floating electrode 110, it does not need to be connected to other detection circuits or the like, and can be formed at low cost.

[0078] Furthermore, since the boundary 120A between adjacent electrodes 120 among the plurality of electrodes 120 is linear in a plan view, the capacitor formed between the driving electrode 120Tx and the detecting electrode 120Rx can have a simple shape and is easy to manufacture.

[0079] Furthermore, the MCU 160 switches the combination of the electrodes 120 selected as the drive electrodes 120Tx and the detection electrodes 120Rx multiple times so that each of the multiple electrodes 120 is selected as the detection electrode 120Rx at least once. By selecting each of the multiple electrodes 120 as the detection electrode 120Rx at least once, each electrode 120 is always selected as the detection electrode 120Rx, which improves the detection accuracy of the pressing operation.

[0080] Furthermore, the multiple electrodes 120 have multiple boundaries 120A between adjacent electrodes 120, and the MCU 160 switches the combination of electrodes 120 selected as the drive electrodes 120Tx and the detection electrodes 120Rx multiple times so that each of the multiple boundaries 120A is located between the drive electrodes 120Tx and the detection electrodes 120Rx at least once. All of the boundaries 120A between adjacent electrodes 120 become boundaries 120B between the drive electrodes 120Tx and the detection electrodes 120Rx, and the capacitance of the detection electrodes 120Rx is detected using all of the boundaries 120A as boundaries 120B. Therefore, the output of the detection electrodes 120Rx is equalized regardless of the position of the pressing operation, thereby improving the detection accuracy of the pressing operation.

[0081] Furthermore, when the skin 104 and the floating electrode 110 are made of a transparent material, the skin 104 can be illuminated by providing a light source on the upper surface of the substrate 101, for example. Also, a decorative layer can be provided on the lower surface side of the skin 104.

[0082] Furthermore, since the foam layer 102 is thicker than the skin 104, it bends smoothly in response to a pressing operation, and an appropriate distance can be secured between the floating electrode 110 and the electrode 120, thereby improving the detection accuracy of the pressing operation.

[0083] Furthermore, the plurality of electrodes 120 are divided into N equal parts (N is an integer equal to or greater than 3) in plan view. By using the plurality of electrodes 120 each having a shape divided into N equal parts, it is possible to appropriately detect the operation position on operation surface 104A.

[0084] The output detection method in the input device is an output detection method in an input device including a skin 104 having an operation surface 104A, a first electrode (floating electrode 110) arranged on the back side of the operation surface 104A, a plurality of electrodes 120 arranged opposite to the first electrode (floating electrode 110), a foam layer 102 arranged between the skin 104 and the plurality of electrodes 120, and an MCU 160 connected to the plurality of electrodes 120, in which the skin 104 and the foam layer 102 are elastically deformed by a pressing operation on the operation surface 104A of a fingertip FT. The MCU 160 selects at least one electrode 120 from the plurality of electrodes 120 as a driving electrode 120Tx, selects at least one electrode 120 from the plurality of electrodes 120 adjacent to the electrode 120 selected as the driving electrode 120Tx as a detection electrode 120Rx, switches the combinations of electrodes 120 selected from the plurality of electrodes 120 as the driving electrode 120Tx and the detection electrode 120Rx, and detects the output of the detection electrode 120Rx in the plurality of combinations.

[0085] Therefore, by detecting the output of the detection electrode 120Rx in multiple combinations of electrodes 120 selected as the driving electrode 120Tx and the detection electrode 120Rx, the output of the detection electrode 120Rx is equalized regardless of the position of the pressing operation on the first electrode (floating electrode 110) and the driving electrode 120Tx and the detection electrode 120Rx.

[0086] Therefore, it is possible to provide an output detection method for an input device that can detect the amount of pressing operation with high accuracy.

[0087] <First Modification> 5A is a diagram showing an example of a combination of selected drive electrodes 120Tx and detection electrodes 120Rx according to a first modified example of the embodiment. Similar to FIG. 3C, FIG. 5A shows an example of a combination of selected drive electrodes 120Tx and detection electrodes 120Rx that are switched eight times.

[0088] 5A shows eight electrodes 120 obtained by dividing an overall circular electrode into eight equal parts, as in FIG. 3C. In a first modification, one of the eight electrodes 120 is selected as a drive electrode 120Tx, and the remaining seven are selected as detection electrodes 120Rx. In this case, the detection electrodes 120Rx connected to the detection unit 150 via the multiplexer 140 may be all seven detection electrodes 120Rx, or may be one or two detection electrodes 120Rx adjacent to one electrode 120 serving as the drive electrode 120Tx.

[0089] By shifting the drive electrodes 120Tx one by one eight times, the combination of electrodes 120 selected as the drive electrodes 120Tx and the detection electrodes 120Rx is switched multiple times so that each of the eight electrodes 120 is selected as the detection electrode 120Rx at least once, as shown in Fig. 5A. Furthermore, the combination of electrodes 120 selected as the drive electrodes 120Tx and the detection electrodes 120Rx is switched multiple times so that each of the eight boundaries 120A is located between the drive electrodes 120Tx and the detection electrodes 120Rx at least once. This makes it possible to provide an input device 100 that can detect the amount of a pressing operation with high accuracy.

[0090] <Second Modification> 5B is a diagram showing an example of a combination of selected driving electrodes 120Tx and detecting electrodes 120Rx according to a second modified example of the embodiment. Similar to FIG. 3B, FIG. 5B shows eight electrodes 120 obtained by dividing a circular electrode into eight equal parts.

[0091] 5B shows an example of a combination of selections at times t1, t2, and t3. In FIG. 5B, the electrodes 120 selected as the drive electrodes 120Tx are indicated by dots, and the electrodes 120 selected as the detection electrodes 120Rx are indicated by white dots. The electrodes 120 held at ground potential are indicated by black dots. The substrate 101 is omitted from FIG. 5B.

[0092] In this way, the electrodes 120 that are not selected as the driving electrodes 120Tx and the detecting electrodes 120Rx may be set as ground electrodes. Note that the driving electrodes 120Tx and the detecting electrodes 120Rx located on both sides of the ground electrode are far apart from each other, and therefore the detecting electrodes 120Rx cannot obtain a sufficient capacitance Crt (see FIG. 1), and therefore the boundary 120B at which the detecting unit 150 detects the capacitance Crt is the portion where the driving electrodes 120Tx and the detecting electrodes 120Rx are adjacent to each other.

[0093] The electrodes 120 that are not selected as the driving electrodes 120Tx and the detecting electrodes 120Rx may be held at a predetermined potential (constant potential) rather than at ground potential (0 V). The presence of the electrodes 120 at a constant potential stabilizes operation.

[0094] <Third Modification> FIG. 6A is a cross-sectional view showing an example of the configuration of an input device 100M3 according to a third modified example of the embodiment.

[0095] The input device 100M3 has two foam layers 102A and 102B. The foam layer 102A is an example of an elastic member and is an example of a first elastic member. The foam layer 102B is an example of a second elastic member.

[0096] The foam layer 102A is obtained by dividing the foam layer 102 of the input device 100 shown in FIG. 1 into two layers. In the input device 100M3, the floating electrode 110 is provided on the lower surface of a sheet 110A provided between the foam layers 102A and 102B. The sheet 110A may be made of an elastically deformable resin or the like, and as an example, a polyimide sheet may be used. In this case, the floating electrode 110 may be formed on the lower surface of the polyimide sheet 110A by vapor deposition, printing, or the like.

[0097] In the input device 100M3, the distance between the floating electrode 110 and the fingertip FT is longer than in the input device 100 shown in Figure 1, so the capacitance Cfg (see Figure 1) between the floating electrode 110 and the fingertip FT is smaller, and fluctuations in the output of the detection electrode 120Rx depending on the position where the pressing operation is performed on the operation surface 104A are further suppressed, making it possible to detect the amount of pressing operation with high accuracy.

[0098] Furthermore, in the input device 100M3, compared to the input device 100 shown in FIG. 1, the foam layer 102B is present directly under the skin 104, which improves the feel when pressing with the fingertip FT.

[0099] <Simulation results for Modification 3> 6B is a diagram showing an example of the relationship between the pressing force when a pressing operation is performed on the input devices 100 and 100M3 and the capacitance detected by the detection unit 150. In the simulation, four driving electrodes 120Tx and four detecting electrodes 120Rx were selected from the eight electrodes 120 as shown in FIG. 3A, and the electrodes 120 were shifted one by one as shown in FIG. 3B, and the boundary 120B was moved at least once around the electrodes 120B, thereby calculating the capacitance detected by the detection unit 150.

[0100] 6B, the horizontal axis represents pressure (N). 0N on the horizontal axis indicates a position where the pressure is zero, representing a state in which the fingertip FT touches the operation surface 104A (a state in which a touch operation has been performed). The vertical axis represents the capacitance detected by the detection unit 150 as a count value (without units). The characteristics of the pressure operation on the input device 100 are indicated by a solid line, and the characteristics of the pressure operation on the input device 100M3 are indicated by a dashed line.

[0101] As shown in Fig. 6B, the capacitance of the pressing operation (dashed line) in the input device 100M3 was greater than the capacitance of the pressing operation (solid line) in the input device 100. As shown in Fig. 6A, it was confirmed that the detection sensitivity for the pressing operation was increased by providing the floating electrode 110 between the two foam layers 102A and 102B. This increase in detection sensitivity was the same in both the central and peripheral parts of the operation surface 104A.

[0102] <Fourth Modification> 7A is a diagram showing an example of a combination of selected driving electrodes 120Tx and detecting electrodes 120Rx according to a fourth modified example of the embodiment. The electrodes 120 in the fourth modified example have a configuration in which a square electrode as a whole is equally divided into nine electrodes in a lattice pattern of three rows and three columns. Therefore, the shape of each electrode 120 is also square.

[0103] Fig. 7A shows an example of the combinations selected in the first to ninth measurements. In Fig. 7A, the electrodes 120 selected as the driving electrodes 120Tx are indicated by dots, and the electrodes 120 selected as the detecting electrodes 120Rx are indicated by outlined parts. In Fig. 7A, the substrate 101 is omitted.

[0104] Here, a description will be given of a configuration in which one of the nine electrodes 120 is selected as the drive electrode 120Tx and the remaining eight are selected as the detection electrodes 120Rx. Conversely, one of the nine electrodes 120 may be selected as the detection electrode 120Rx and the remaining eight may be selected as the drive electrodes 120Tx.

[0105] An AC drive voltage is supplied to one drive electrode 120Tx from a power supply 130 via a multiplexer 140. Furthermore, the eight detection electrodes 120Rx are connected to a detection unit 150 via the multiplexer 140. Therefore, the detection unit 150 detects the capacitance of the eight detection electrodes 120Rx. Note that one or more electrodes 120 adjacent to or surrounding one drive electrode 120Tx may be selected as the detection electrodes 120Rx.

[0106] In the first to ninth measurements, the driving electrodes 120Tx are shifted one by one, so that at least one of the nine electrodes 120 can be selected as the driving electrode 120Tx, as shown in FIG. 7A.

[0107] 7A, a configuration in which square electrodes 120 are arranged is suitable for uniform detection over a wide area. In addition, since the shape of the electrodes 120 is simple, it has the advantage of being easy to fabricate multiple electrodes 120 and to wire them.

[0108] In this way, by shifting the boundary 120B between the drive electrodes 120Tx and the detection electrodes 120Rx in a time-division manner, it is possible to equalize the detection sensitivity across all nine electrodes 120. By equalizing the detection sensitivity across all nine electrodes 120, it becomes possible to detect the amount of pressing operation with high accuracy.

[0109] Furthermore, the nine electrodes 120 shown in Fig. 7A may be modified as shown in Fig. 7B. Fig. 7B is a diagram showing an example of a configuration in which the electrode 120 of the fourth modified example is further modified.

[0110] 7B shows a configuration in which nine regular hexagonal electrodes 120 are arranged in three rows and three columns, like a honeycomb structure. Each electrode 120 has the same shape and size. As shown in FIG. 7B, by using a plurality of electrodes 120 arranged to form a honeycomb structure, for example, in the first to ninth measurements, by shifting the driving electrodes 120Tx by one, it is possible to select at least one of the nine electrodes 120 as the driving electrode 120Tx, as shown in FIG. 7B.

[0111] 7B, a configuration in which regular hexagonal electrodes 120 are arranged is suitable for uniform detection over a wide area. In addition, since the shape of the electrodes 120 is simple, it has the advantage of being easy to fabricate multiple electrodes 120 and to wire them.

[0112] In the fourth modified example, the configuration in which the plurality of electrodes 120 are arranged in a lattice pattern ( FIG. 7A ) or a honeycomb pattern ( FIG. 7B ) has been described, but the present invention is not limited to these, and the electrodes 120 may be arranged in a ring shape, for example. The shape and size of each of the plurality of electrodes 120, or the overall arrangement thereof, may be set within the range used to detect a pressing operation, depending on the size and shape of the operation surface 104A. By optimizing the shape and size of each of the plurality of electrodes 120, or the overall arrangement thereof, the amount of pressing operation can be detected appropriately and with high accuracy.

[0113] The above describes an input device and an output detection method in an input device according to exemplary embodiments of the present disclosure. However, the present disclosure is not limited to the specifically disclosed embodiments, and various modifications and variations are possible without departing from the scope of the claims.

[0114] This international application claims priority based on Japanese Patent Application No. 2022-200578, filed on December 15, 2022, the entire contents of which are incorporated herein by reference. [Explanation of symbols]

[0115] FT Fingertip (an example of an operating object) 100, 100M3 input device 101 Substrate 102 Foam layer (an example of an elastic member) 102A foam layer (an example of an elastic member, an example of a first elastic member) 102B foam layer (an example of the second elastic member) 104 Epidermis 104A Operation surface 110 Floating electrode (an example of the first electrode) 110A seat 120 electrode (an example of a plurality of second electrodes) 120A Boundary (Example of boundary between adjacent second electrodes) 120Tx drive electrode 120Rx detection electrode 130 Power supply 140 Multiplexer 150 Detector 160 MCU (an example of a control unit)

Claims

1. a skin having an operation surface; a first electrode disposed on the rear side of the operation surface; a plurality of second electrodes arranged opposite the first electrodes; an elastic member disposed between the skin and the plurality of second electrodes; a control unit connected to the plurality of second electrodes; Including, the skin and the elastic member are elastically deformable by a pressing operation of an operating body against the operating surface, The control unit selecting at least one second electrode as a drive electrode from among the plurality of second electrodes; selecting, as a detection electrode, at least one second electrode adjacent to the second electrode selected as the drive electrode from among the plurality of second electrodes; An input device that switches combinations of second electrodes selected as the drive electrodes and the detection electrodes from among the plurality of second electrodes, and detects outputs of the detection electrodes in the plurality of combinations.

2. The input device of claim 1 , wherein the first electrode is a floating electrode.

3. The input device according to claim 1 , wherein a boundary between adjacent second electrodes among the plurality of second electrodes is linear in plan view.

4. 4. The input device according to claim 1, wherein the control unit switches a combination of the drive electrodes and the second electrodes selected as the detection electrodes multiple times so that each of the plurality of second electrodes is selected as the detection electrode at least once.

5. the plurality of second electrodes have a plurality of boundaries between adjacent second electrodes, 5. The input device according to claim 4, wherein the control unit switches the combination of the second electrodes selected as the drive electrodes and the detection electrodes multiple times so that each of the multiple boundaries is located between the drive electrodes and the detection electrodes at least once.

6. The input device according to claim 4 , wherein the control unit holds at least one of the second electrodes that are not selected as the drive electrodes or the detection electrodes, at a constant potential.

7. The input device according to claim 1 , wherein the skin and the first electrode are made of a transparent material.

8. The input device according to claim 1 , wherein the elastic member is thicker than the skin.

9. The input device according to claim 1 , wherein the second electrodes are arranged in a ring-like, lattice-like, or honeycomb-like pattern in a plan view.

10. The input device according to claim 9 , wherein the plurality of second electrodes are divided into N equal parts (N is an integer of 3 or more) in a plan view.

11. a skin having an operation surface; a first electrode disposed on the rear side of the operation surface; a plurality of second electrodes arranged opposite the first electrodes; an elastic member disposed between the skin and the plurality of second electrodes; a control unit connected to the plurality of second electrodes; An output detection method in an input device comprising: the skin and the elastic member are elastically deformable by an operator pressing the operation surface, The control unit selecting at least one second electrode as a drive electrode from among the plurality of second electrodes; selecting, as a detection electrode, at least one second electrode adjacent to the second electrode selected as the drive electrode from among the plurality of second electrodes; An output detection method for an input device, comprising: switching combinations of second electrodes selected as the drive electrodes and the detection electrodes from among the plurality of second electrodes; and detecting outputs of the detection electrodes in the plurality of combinations.

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