JP2017078888A - Touch panel device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow a touched position to be detected by a simple structure in a touch panel device having a pressing force detection function.SOLUTION: A touch panel device has a first insulator, a second insulator, an elastic material, a first electrode pattern 13, a second electrode pattern 15, and a third electrode pattern 17. An impedance circuit 53 is connected to the third electrode pattern 17 and can change an impedance between a reference potential and the third electrode pattern 17. An impedance change control circuit 65 changes the impedance of the impedance circuit 53 into two levels, a higher level and a lower level. An electrostatic capacitance detection circuit 51 detects an electrostatic capacitance generated at an intersection between the first electrode pattern 13 and the second electrode pattern 15. A pressing force calculation circuit 63 calculates pressing force at the intersection by an operation using an electrostatic capacitance when the impedance circuit 53 has a higher impedance and an electrostatic capacitance when the impedance circuit 53 has a lower impedance.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a touch panel device, and more particularly to a touch panel device having a pressing force detection function.

  The touch panel device has a function of detecting a position pressed by a finger or the like. For example, a capacitive touch panel device has a first electrode pattern and a second electrode pattern that maintains insulation between the first electrode pattern and is arranged in parallel with the first electrode pattern. doing. In this apparatus, a touch position is detected based on a change in electrostatic capacitance at an intersection caused by a finger touch.

In recent years, touch panel devices that detect not only the pressed position but also the pressing force have been developed. The function of detecting the pressing force is realized by combining a piezoelectric sensor with a touch panel, for example.
Further, in the capacitive touch panel device, the first electrode pattern when the pressing force is applied in the structure in which the first electrode pattern and the second electrode pattern are arranged apart from each other in the stacking direction across the elastic body, A technique for detecting a pressing force based on an increase in capacitance due to the approach of the second electrode pattern has also been introduced (see, for example, Patent Document 1).

Special table 2013-529803 gazette

  However, in the configuration as in Patent Document 1, it is difficult to detect a change in capacitance unless the elastic body is sufficiently compressed, and when the pressing force is small, that is, when the load is small, it is possible to detect the touched position. was difficult. Further, for the purpose of detecting a touched position even with a small pressing force, it is conceivable to separately stack a projected capacitive touch panel. However, in this case, the number of electrode layers increases, which complicates the device structure and control circuit.

  An object of the present invention is to enable detection of a touched position with a simple structure in a touch panel device having a pressing force detection function.

  Hereinafter, a plurality of modes will be described as means for solving the problems. These aspects can be arbitrarily combined as necessary.

The touch panel device according to an aspect of the present invention can detect a pressing force. The touch panel device includes a first insulator and a second insulator, an elastic body, a first electrode pattern, a second electrode pattern, a third electrode pattern, an impedance circuit, an impedance change control circuit, and a capacitance. It has a detection circuit and a pressing force calculation circuit.
The first insulator and the second insulator are stacked.
The elastic body is provided between the first insulator and the second insulator and has lower rigidity than each of the first insulator and the second insulator.
The first electrode pattern has a plurality of first electrodes provided on a surface of the first insulator opposite to the second insulator.
The second electrode pattern includes a plurality of second electrodes provided between the first insulator and the elastic body so as to form a plurality of intersections in plan view with respect to the plurality of first electrodes. .
The third electrode pattern is entirely provided between the elastic body and the second insulator.
The impedance circuit is connected to the third electrode pattern and can change the impedance between the reference potential and the third electrode pattern.
The impedance change control circuit changes the impedance of the impedance circuit in two stages of high and low.
The capacitance detection circuit detects the capacitance generated at the intersection of the first electrode pattern and the second electrode pattern.
The pressing force calculation circuit calculates the pressing force at the intersection by calculation using the capacitance when the impedance circuit is high impedance and the capacitance when the impedance circuit is low impedance.

In this device, when the finger presses the first insulator and the second insulator, the capacitance detection circuit detects the capacitance generated at the intersection of the first electrode pattern and the second electrode pattern corresponding to the pressed position. To do. Thereby, a press position is calculated.
In addition, the impedance change control circuit changes the impedance of the impedance circuit into two levels of high and low, and the pressing force calculation circuit further determines the capacitance when the impedance circuit is high impedance and the static when the impedance circuit is low impedance. The pressing force is calculated by calculation using the electric capacity. The type of calculation is not particularly limited.
As a result, the touch panel device can detect a small pressing force with a simple structure.

The operation of measuring the capacitance by the capacitance detection circuit includes the first measurement step of measuring the capacitance at each intersection point while the impedance circuit is in a high impedance state, and the static measurement at each intersection point when the impedance circuit is in a low impedance state. A second measurement step of measuring the capacitance. The operation of calculating the pressing force by the pressing force calculation circuit is performed after the first measurement step and the second measurement step are completed.
In this apparatus, since the operation of calculating the pressing force by the pressing force calculation circuit is performed after the first measurement step and the second measurement step, the calculation efficiency is improved.

The capacitance detection circuit may select an intersection at which measurement is performed in a later step based on the result of the step previously executed out of the first measurement step and the second measurement step. For example, only intersections that are likely to be pressed positions or related to the pressed positions are selected.
In this apparatus, since the number of intersections at which measurement is performed in a step to be executed later is reduced, the operation and time for capacitance detection are reduced.

The second insulator may be a polarizing plate on the image display surface.
In this device, the number of parts is reduced, thereby simplifying the structure.

  In the touch panel device according to the present invention, a small pressing force can be detected with a simple structure.

The schematic sectional drawing of a touch panel. The schematic plan view of a 1st electrode pattern. The schematic plan view of a 2nd electrode pattern. The schematic plan view of a 3rd electrode pattern. The schematic plan view of the state which piled up the 1st electrode pattern and the 2nd electrode pattern. The control block diagram of a touch-panel apparatus. The figure which shows the 1st example of an impedance circuit. The figure which shows the 2nd example of an impedance circuit. The schematic sectional drawing which shows the electric lines of force in a touch panel. The schematic sectional drawing which shows the electric lines of force in a touch panel. The schematic sectional drawing which shows the electric lines of force in a touch panel. The flowchart which shows the control operation of a touch panel apparatus. The flowchart which shows the electrostatic capacitance value measurement operation | movement of each intersection. The flowchart which shows the electrostatic capacitance value measurement operation | movement of each intersection. The flowchart which shows the calculation operation of a measured value. The table | surface which shows the simulation result of an Example. The flowchart which shows the control operation of the touch panel apparatus in 2nd Embodiment. The schematic sectional drawing of the touch panel in 3rd Embodiment.

  Hereinafter, embodiments will be described with reference to the drawings.

1. First Embodiment (1) Structure of Touch Panel Touch panel 1 shown in FIG. 1 is a device that constitutes a part of touch panel device 3 (FIG. 6). The touch panel 1 has a function of detecting a pressing position and a function of detecting a pressing force. FIG. 1 is a schematic cross-sectional view of the touch panel.

The touch panel 1 has a protective layer 5. The first surface of the protective layer 5 is an input surface that is touched by a finger. The protective layer 5 is a layer for protecting an electrode pattern, which will be described later, and has a function of preventing conduction between the finger and the electrode pattern and preventing damage to the electrode pattern. The protective layer 5 is an arbitrary member and can be omitted.
The protective layer 5 must not be damaged by the applied impact, and examples thereof include a glass plate and a resin plate. As the material of the glass plate, chemically tempered glass is preferable, and as the material of the resin plate, acrylic resin, polycarbonate resin and the like are preferable.

The touch panel 1 includes a first insulator 7, an elastic body 9, a second insulator 11, a first electrode pattern 13, a plurality of second electrode patterns 15, and a third electrode pattern 17.
The first insulator 7 and the second insulator 11 are provided in a stacked manner. Specifically, the first insulator 7 is provided on the second surface opposite to the first surface of the protective layer 5. The second insulator 11 is provided on the surface of the first insulator 7 opposite to the protective layer 5.
The elastic body 9 is provided between the first insulator 7 and the second insulator 11. The elastic body 9 is a member that can be elastically deformed when the protective layer 5 is pressed with a finger, for example. On the other hand, the first insulator 7 and the second insulator 11 are members that hardly elastically deform or slightly deform when the protective layer 5 is pressed with a finger, for example.

The first electrode pattern 13 is provided on the second surface (the surface on the protective layer 5 side) of the first insulator 7. The plurality of second electrode patterns 15 are provided on the second surface (surface on the elastic body 9 side) of the first insulator 7. As a result, the second electrode pattern 15 maintains insulation with the first electrode pattern 13 and is arranged so as to intersect with the first electrode pattern 13. The first electrode pattern 13 and the second electrode pattern 15 are drawn out to the connection terminal (not shown) by a lead wiring (not shown).
The third electrode pattern 17 is provided between the elastic body 9 and the second insulator 11.

  As shown in FIG. 2, the first electrode pattern 13 is an X direction electrode arranged in the X direction in the figure. As shown in FIG. 3, the second electrode pattern 15 is a Y-direction electrode arranged in the Y direction in the figure. As shown in FIG. 4, the third electrode pattern 17 is formed over the entire surface so as to cover the first electrode pattern 13 and the second electrode pattern 15. FIG. 2 is a schematic plan view of the first electrode pattern. FIG. 3 is a schematic plan view of the second electrode pattern. FIG. 4 is a schematic plan view of the third electrode pattern.

The layout of the first electrode pattern 13, the second electrode pattern 15, and the third electrode pattern 17 will be described in more detail with reference to FIGS. The first electrode pattern 13 and the second electrode pattern 15 are so-called diamond patterns.
The first electrode pattern 13 includes a plurality of first electrodes 13a (x0, x1, x2,..., Xn) extending in the Y direction and arranged in the X direction. Each first electrode 13a includes a plurality of rhombus electrodes 21 and a plurality of connection wires 23 that connect the rhombus electrodes 21 to each other in the vertical direction (Y direction) in the drawing. The second electrode pattern 15 has a plurality of second electrodes 15a (y0, y1, y2,..., Ym) extending in the X direction and arranged in the Y direction. Each of the second electrodes 15a includes a plurality of rhombus electrodes 31 and a plurality of connection wires 33 that connect the rhombus electrodes 31 to each other in the horizontal direction (X direction) in the figure. The plurality of first electrodes 13a and the plurality of second electrodes 15a form a plurality of intersections in plan view. As described above, the third electrode pattern 17 is entirely formed between the elastic body 9 and the second insulator 11, and constitutes a full surface electrode 17a. The third electrode pattern may be mesh.
A gap is secured between the first electrodes 13a, and a gap is secured between the second electrodes 15a.

  As shown in FIG. 5, the arrangement relationship between the rhombus electrode 21 and the rhombus electrode 31 is complementary in plan view. That is, the plurality of rhombus electrodes 31 are arranged so as to fill in the rhombus-shaped gaps that occur when the rhombus electrodes 21 are arranged in a matrix. In other words, the plurality of first electrodes 13a (x0, x1, x2,..., Xn) and the plurality of second electrodes 15a (y0, y1, y2,..., Ym) are also the third electrodes from the input surface side. Most of the pattern 17 is also exposed. FIG. 5 is a schematic plan view showing a state in which the first electrode pattern and the second electrode pattern are overlaid.

  As described above, since the X-direction electrode and the Y-direction electrode are arranged so as to form an intersection point in plan view, the contact position of the finger and its pressing force can be detected by measuring the mutual capacitance of the intersection point. . That is, when the finger approaches the first electrode 13a and the second electrode 15a, the mutual capacitance at the intersection point close to the contact position changes, and the elastic body is deformed by the pressing, and the first electrode 13a and the second electrode 15a become the first electrode. By approaching the three-electrode pattern 17, the mutual capacitance at the intersection changes, so that the finger contact position and the pressing force can be detected by detecting this. The mutual capacitance at the intersection is a capacitance between any one electrode xi of the first electrodes 13a and any one electrode yi of the second electrodes 15a.

As a material for the base film used as an insulator, transparent polyester (PET), polyimide (PI), polyethersulfone (PES), polyetheretherketone (PEEK), polycarbonate (PC), polypropylene ( PP), polyamide (PA), polyacrylic (PAC), norbornene-based thermoplastic transparent resin films, or laminates thereof are used. Cycloolefin polymers (COP) can also be used. Note that the insulator may be opaque.
The thickness of the base film is usually 20 μm or more as a single thickness of each film, and the total thickness of each film is 500 μm or less. If the single thickness is less than 20 μm, handling during film production is difficult, and if the total thickness exceeds 500 μm, the translucency is lowered.

  As materials for the first electrode pattern 13, the second electrode pattern 15, and the third electrode pattern 17, a light transmittance (translucency) of 80% or more and a surface resistance value (conductivity) of several mΩ to several hundred Ω. It is preferable to use metal oxides such as indium oxide, tin oxide, indium tin oxide (ITO), and tin antimonic acid, and metals such as gold, silver, copper, platinum, palladium, aluminum, and rhodium. Can be membrane. As a method for forming the first electrode pattern 13 and the second electrode pattern 15 made of these materials, a transparent conductive film is formed by a PVD method such as a sputtering method, a vacuum deposition method, or an ion plating method, or a CVD method or a coating method. There are a method of patterning by etching after forming, a printing method, and the like.

The elastic modulus of the elastic body 9 is preferably in the range of 0.001 MPa to 10 MPa.
The material of the elastic body 9 may be silicone or polyurethane.
The thickness of the elastic body 9 is preferably in the range of 10 μm to 2000 μm, and more preferably in the range of 50 μm to 1000 μm.

(2) Control Configuration of Touch Panel Device The control configuration of the touch panel device 3 will be described with reference to FIG. FIG. 6 is a control configuration diagram of the touch panel device.
The touch panel device 3 has a capacitance detection circuit 51. A plurality of first electrodes 13a (x0, x1, x2,..., Xn) and a plurality of second electrodes 15a (y0, y1, y2,..., Ym) are connected to the capacitance detection circuit 51. Yes. Thereby, the capacitance detection circuit 51 can detect the mutual capacitance at the intersection of the first electrode pattern 13 and the second electrode pattern 15. Specifically, the capacitance detection circuit 51 sequentially applies voltage pulses using the plurality of first electrodes 13a as transmission electrodes and measures the reception intensity using the plurality of second electrodes 15a as reception electrodes. The change in mutual capacitance at each electrode intersection is detected. Thereafter, the capacitance detection circuit 51 outputs a level signal at each intersection to the control unit 55.

The touch panel device 3 has an impedance circuit 53. Impedance circuit 53 is connected to the third electrode pattern 17, it is possible to change the impedance between the reference potential V _R and the third electrode pattern 17. Incidentally, the reference potential _{V R} is the ground (GND) or other fixed potential. A specific example of the impedance circuit 53 will be described with reference to FIG. 7A (first example) and FIG. 7B (second example).
In the first example shown in FIG. 7A, the impedance circuit 53A has a first switch SW ₁ provided between the full-surface electrode 17a and the reference potential _{V R.} The first switch SW ₁ is connected to the entire surface electrode 17a and the reference potential _{V R} (low impedance state), and interrupting (high impedance state).

In the second example shown in FIG. 7B, the impedance circuit 53B includes a first impedance Z1 connected in parallel to a reference potential V _R and a second impedance Z2. Impedance circuit 53B further includes a second switch SW ₂ which is provided between the the full-surface electrode 17a and the first impedance Z1 and a second impedance Z2. The second switch SW ₂ switches the connection between the state of connecting the whole surface electrode 17a to the first impedance Z1 state and a second impedance connected to a (low impedance state) Z2 (high impedance state). In other words, impedance connected between the full-surface electrode 17a and the reference potential V _R is set to be changed. In this embodiment, the value of the first impedance Z1 is desirably sufficiently small, and the value of the second impedance Z2 is desirably sufficiently larger than the value of the first impedance Z1.
The first switch and the second switch are realized by, for example, a transistor, an analog switch, a relay, a triac, a thyristor, or the like.

The touch panel device 3 has a control unit 55. The control unit 55 is a computer having a CPU, a ROM, a RAM, and the like, for example. A capacitance detection circuit 51 and an impedance circuit 53 are connected to the control unit 55. The control unit 55 controls the detection timing of the capacitance by the capacitance detection circuit 51 and the switching timing of the impedance circuit 53.
The control unit 55 has a pressed position calculation circuit 61. The pressing position calculation circuit 61 is a device that calculates the pressing position based on a level signal indicating a change in mutual capacitance at each intersection from the capacitance detection circuit 51. Since the technique for calculating the pressed position is known, the description thereof is omitted.

The control unit 55 has a pressing force calculation circuit 63. The pressing force calculation circuit 63 calculates the pressing force based on the level signal indicating the change in mutual capacitance at each intersection from the capacitance detection circuit 51. As a feature of the present embodiment, the pressing force calculation circuit 63 is calculated at the intersection point by calculation using the electrostatic capacity when the impedance circuit 53 is high impedance and the electrostatic capacity when the impedance circuit 53 is low impedance. Calculate the pressing force. This will be described in detail later.
The control unit 55 has an impedance change control circuit 65. The impedance change control circuit 65 changes the impedance of the impedance circuit 53 in two stages of high and low.

The control unit 55 has a memory 67. The memory 67 is a device capable of storing programs and data. Note that the memory 67 may exist in a device other than the control unit 55.
The pressing position calculation circuit 61, the pressing force calculation circuit 63, and the impedance change control circuit 65 are functions realized by executing a program in the control unit 55, for example. These may be realized by hardware such as an independent IC.

Hereinafter, the touch detection operation of the touch panel device 3 will be schematically described.
In this apparatus, for example, when a finger presses the protective layer 5 (that is, presses the first insulator 7), the electrostatic capacitance detection circuit 51 is generated at the intersection of the first electrode pattern 13 and the second electrode pattern 15. Detect capacitance. Thereby, the pressing position calculation circuit 61 detects the pressing position.

In addition, the impedance change control circuit 65 changes the impedance of the impedance circuit 53 into two levels of high and low, and the pressing force calculation circuit 63 further reduces the capacitance when the impedance circuit 53 is high impedance and the impedance circuit 53 is low. The pressing force is calculated by calculation using the capacitance in the case of impedance.
As a result, in the touch panel device 3 having a pressing force detection function, a touched position can be detected with a simple structure even with a small pressing force.

The operation of detecting the capacitance by the capacitance detection circuit 51 includes a first measurement step in which the capacitance at each intersection is detected with the impedance circuit 53 in a high impedance state, and each operation with the impedance circuit 53 in a low impedance state. A second measurement step of detecting the capacitance of the intersection. The operation of calculating the pressing force by the pressing force calculation circuit 63 is performed after the first measurement step and the second measurement step are completed.
In this apparatus, since the operation of calculating the pressing force by the pressing force calculation circuit 63 is performed after the first measurement step and the second measurement step, the calculation efficiency is improved.

(3) change principle diagram 8 of a mutual capacitance at the intersection, with reference to FIGS. 9 and 10, the mutual capacitance _{C1 ij} and in which is one electrode xi of the first electrode 13a (0 <= i <= n, 0 < = J <= m) The elastic body 9 in which the mutual capacitance C2 _ij (0 <= i <= n, 0 <= j <= m) in the electrode yj, which is one of the second electrodes 15a, is caused by contact or pressing of the finger. It will be schematically described how it changes due to the deformation of. 8 to 10 are schematic cross-sectional views showing electric lines of force in the touch panel.

As illustrated in FIG. 8, C1 _ij and C2 _ij when the finger is not touching the touch panel device 3 are expressed as C1 ^REF _ij and C2 ^REF _ij , respectively. These values are measured in a state where there is clearly no touch such as immediately after the power of the electronic device including the touch panel device 3 is turned on, and are stored in the memory 67 of the control unit 55.
Here, it is important that the lines of electric force from the electrode xi and the electrode yj cover the second electrode pattern 15 and extend to the third electrode pattern 17. In order to enable such a phenomenon, it is necessary to configure such that at least a part of the first electrode pattern exists in a plurality of gaps between the second electrodes 15a of the second electrode pattern 15. .

As shown in FIG. 9, when the finger touches the protective layer 5, for example, the mutual capacitance _C1ij and the mutual capacitance _C2ij change as much as the finger blocks the electric field lines. When the elastic body 9 is not deformed while the finger is lightly touching the protective layer 5, the amount of change is not related to the impedance circuit 53, so the mutual capacitance _C1ij and the mutual capacitance _C2ij change by the same amount. When the amount of change is ΔC ^FNG _ij , mutual capacitances C1 ^A _ij and C2 ^A _ij at each intersection at this time are expressed as follows.
C1 ^A _ij = C1 ^REF _ij + ΔC ^FNG _ij (formula 1)
C2 ^A _ij = C2 ^REF _ij + ΔC ^FNG _ij (formula 2)
It becomes.

As shown in FIG. 10, when the finger strongly presses the protective layer 5, the elastic body 9 is deformed according to the force, and the electrode xi and the electrode yj approach the third electrode pattern 17 (entire electrode 17a). Due to this, the mutual capacitance further changes. When the first switch SW ₁ and the second switch SW ₂ of the impedance circuit 53 realize the low impedance state or the high impedance state, the amount of change is ΔC1 ^FS _jj and the high impedance state when the low impedance state is achieved. Is ΔC2 ^FS _ij . Is this amount of change in the first example of the impedance (FIG. 7A of the entire surface electrodes 17a and is either not or is connected to a reference potential V _R, in the second example of Figure 7B are connected to the first impedance Z1 Or the second impedance Z2). The mutual capacitances C1 ^B _ij and C2 ^B _ij at each intersection at this time are expressed as follows.

C1 ^B _ij = C1 ^REF _ij + ΔC ^FNG _ij + ΔC1 ^FS _ij (formula 3)
C2 ^B _ij = C2 ^REF _ij + ΔC ^FNG _ij + ΔC2 ^FS _ij (formula 4)
In this ^case, when calculating the _{C2 B ij} ^-C1 B ij, it is as follows.
_{^{C2 B ij -C1 B ij = C1}} REF ij -C2 REF ij + ΔC2 FS ij -ΔC1 FS ij
... (Formula 5)

Here, C1 ^REF _ij -C2 ^REF _ij is a constant value. Further, .DELTA.C1 ^FS _ij is because it is connected to the reference potential V _R is a negative value, the pressing force is large (i.e., deformation is large) uniquely absolute value increases with. ΔC2 ^FS _ij is a value that is positively larger than ΔC1 ^FS _ij , and when the pressing force increases (that is, deformation increases), the absolute value uniquely increases. That is, ΔC2 ^FS _ij −ΔC1 ^FS _ij uniquely increases when the pressing force increases (that is, deformation increases). ^Thus, by using the _{C2 B ij} ^-C1 B ij, it can detect the pressing force.
Thus, when the pressing force is small, as shown in Formula 1 or Formula 2, the pressing position can be detected by detecting C1 ^A _ij or C2 ^A _ij , and when the pressing force is sufficiently large, from Formula 5, ^It can be said that the pressing force can be further detected by the calculation of ^B _ij −C1 ^B _ij .

(4) Detection control of pressing position and pressing force Touch detection control operation of the touch panel 1 by the capacitance detection circuit 51 and the control unit 55 will be described with reference to FIG. FIG. 11 is a flowchart showing the control operation of the touch panel device.
First, the control unit 55 determines whether or not there is a touch based on the level signal from the capacitance detection circuit 51 (step S1).

If it is determined that the touch has been made (Yes in step S1), the impedance change control circuit 65 sets the impedance circuit 53A in a low impedance state (step S2). Specifically, in the first example of FIG. 7A, the whole surface electrode 17a is connected to the reference potential _{V R} by the first switch SW _1. In the second example of FIG. 7B, the second switch SW _2, the whole surface electrode 17a is connected to the first impedance Z1.
In this way, the capacitance detection circuit 51 measures the mutual capacitance C1 _ij at each intersection while keeping the impedance circuit 53 in a low impedance state (step S3). The value of the mutual capacitance _{C2 ij} of each intersection is stored in the memory 67 of the controller 55.

Next, the impedance change control circuit 65 puts the impedance circuit 53 into a high impedance state (step S4). Specifically, in the first example of FIG. 7A, the first full-surface electrode 17a by a switch SW ₁ is turned OFF from the reference potential _{V R.} In the second example of FIG. 7B, the second switch SW _2, the whole surface electrode 17a is connected to the second impedance Z2.
In this way, the capacitance detection circuit 51 measures the mutual capacitance _C2ij at each intersection while keeping the impedance circuit 53 in a high impedance state (step S5). The value of the mutual capacitance C1 _ij at each intersection is stored in the memory 67 of the control unit 55.
The order of detection of the mutual capacitance C1 _ij at each intersection and C2 _ij is not limited to that in the above embodiment.

Next, the pressing force calculation circuit 63 performs a calculation regarding each intersection using the mutual capacitance _C1ij and the mutual capacitance _C2ij of each intersection (step S6). Thereby, the calculation result in each intersection is obtained.
Finally, the control unit 55 determines the touch pressing position and the pressing force by the pressing position calculation circuit 61 and the pressing force calculation circuit 63 (step S7).

The capacitance value measurement control at each intersection in step S3 will be described with reference to FIG. FIG. 12 is a flowchart showing the capacitance value measuring operation at each intersection.
First, the mutual capacitance _C1ij at a certain intersection is measured (step S11). Specifically, the capacitance detection circuit 51 inputs a pulse signal to one of the first electrodes 13a, and detects a signal from one of the second electrodes 15a in that state.

The detected value of the mutual capacitance C1 _ij is sent to the control unit 55 and stored in the memory 67 (step S12).
Next, it is determined whether or not mutual capacitance has been detected at all intersections (step S13). If there is an intersection where no mutual capacitance has been detected (No in step S13), the process returns to step S11. If the mutual capacitance is measured at all intersections (Yes in step S13), the process ends.

The capacitance value measurement control at each intersection in step S5 will be described with reference to FIG. FIG. 13 is a flowchart showing a capacitance value measuring operation at each intersection.
First, the mutual capacitance _C2ij at a certain intersection is measured (step S14). Specifically, the capacitance detection circuit 51 inputs a pulse signal to one of the first electrodes 13a, and detects a signal from one of the second electrodes 15a in that state.

The detected value of the mutual capacitance _C2ij is sent to the control unit 55 and stored in the memory 67 (step S15).
Next, it is determined whether or not mutual capacitance has been detected at all intersections (step S16). If there is an intersection where no mutual capacitance has been detected (No in step S16), the process returns to step S14. If the mutual capacitance is measured at all intersections (Yes in step S16), the process ends.

The calculation of the measurement value, which is step S6 in FIG. 11, will be described in detail with reference to FIG. FIG. 14 is a flowchart showing the calculation operation of the measurement value.
First, the pressing force calculation circuit 63 performs calculation for subtracting the mutual capacitance C1 _ij from the mutual capacitance C2 _{ij at} a certain intersection (step S17).
Next, the pressing force calculation circuit 63 stores the result in the memory 67 (step S18).
It is determined whether or not calculation has been performed for all intersections (step S19). If there is an intersection that has not been calculated (No in step S19), the process returns to step S17. If the calculation is performed for all intersection points (Yes in step S19), the process ends.

(5) Example FEM simulation was performed under the conditions when the protective layer was glass and the elastic coefficient of the elastic body was 0.01 MPa. Specifically, the center of the glass surface was pressed at 0 to 4N, and the change in capacitance between the X direction electrode and the Y direction electrode having an intersection at the pressed position was calculated. Hereinafter, the result will be described with reference to FIG. FIG. 15 is a table showing simulation results of the examples.
As shown in FIG. 15, as the pressing force increases, C1 _ij decreases and conversely C2 _ij increases. As a result, C2 _ij −C1 _ij increases. In this manner, the pressing force can be calculated by calculating C2 _ij −C1 _ij .

2. Second Embodiment In the first embodiment, when measuring the capacitance value of the second intersection in the second embodiment, the measurement is performed for all the intersections, but the present invention is not limited to that embodiment.
A method for measuring the capacitance value at the second intersection in the second embodiment will be described with reference to FIG. FIG. 16 is a flowchart showing the control operation of the touch panel device in the second embodiment.

The capacitance detection circuit 51 selects an intersection at which measurement is performed in a later step based on the result of the step previously executed in the first measurement step and the second measurement step.
Specifically, after step S3 of FIG. 16, which is the step to be executed first, an intersection point for the next measurement is selected (step S10). This means that an intersection point that requires later measurement is selected based on the previous measurement result. That is, an intersection point that is clearly not a pressing point is not a target for subsequent measurement. Specifically, for example, only intersections that have a possibility of a pressing position or are related to the pressing position are selected.
As a result, since the number of intersections to be measured in step S5, which is a measurement step to be executed later, is reduced, the operation and time for detecting the capacitance are shortened.

3. Third Embodiment The second insulator may be a polarizing plate on the image display surface.
In the third embodiment, as shown in FIG. 17, a polarizing plate 73 is provided on the surface of the display unit 71 (liquid crystal display, organic EL display, etc.), and the polarizing plate 73 is the second insulation of the first embodiment. It functions as a body. FIG. 17 is a schematic cross-sectional view of a touch panel in the third embodiment.
In this device, the number of parts is reduced, thereby simplifying the structure.

4). Other Embodiments Although one or more embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention. In particular, a plurality of embodiments and modifications described in this specification can be arbitrarily combined as necessary.
The first electrode pattern and the second electrode pattern are not limited to the aforementioned diamond pattern, and a known pattern that realizes a capacitive touch panel can be used. For example, you may use using electrodes of other shapes, such as a triangle and a quadrangle.

The stacking order of each layer and the presence / absence of other layers are not limited to the above embodiment. The first electrode pattern and the second electrode pattern may be provided on different base films. Moreover, another layer may be provided as needed.
The material and thickness of each layer are not limited to the above embodiment.
The control configuration is not limited to the above embodiment.
The control flowchart is not limited to the above embodiment. Specifically, the order and presence / absence of the plurality of steps are not particularly limited. In particular, the steps described before and after may be performed all simultaneously or partly simultaneously.

  The present invention can be widely applied to touch panel devices, in particular, touch panel devices having a pressing force detection function.

1: Touch panel 3: Touch panel device 7: First insulator 9: Elastic body 11: Second insulator 13: First electrode pattern 13a: First electrode 15: Second electrode pattern 15a: Second electrode 17: Third electrode Pattern 51: Capacitance detection circuit 53: Impedance circuit 55: Control unit 61: Pressing position calculation circuit 63: Pressing force calculation circuit 65: Impedance change control circuit 67: Memory 71: Display unit 73: Polarizing plate

Claims (4)

A first insulator and a second insulator provided in a stack;
An elastic body provided between the first insulator and the second insulator, and having a lower rigidity than each of the first insulator and the second insulator;
A first electrode pattern having a plurality of first electrodes provided on a surface of the first insulator opposite to the second insulator;
A second electrode having a plurality of second electrodes provided between the first insulator and the elastic body so as to form a plurality of intersections in plan view with respect to the plurality of first electrodes. With patterns,
A third electrode pattern provided on the entire surface between the elastic body and the second insulator;
An impedance circuit connected to the third electrode pattern and capable of changing an impedance between a reference potential and the third electrode pattern;
An impedance change control circuit for changing the impedance of the impedance circuit in two stages of high and low;
A capacitance detection circuit for detecting a capacitance generated at an intersection of the first electrode pattern and the second electrode pattern;
A pressing force calculation circuit that calculates the pressing force at the intersection point by calculation using the capacitance when the impedance circuit is high impedance and the capacitance when the impedance circuit is low impedance;
A touch panel device capable of detecting a pressing force. The operation of measuring the capacitance by the capacitance detection circuit includes a first measurement step in which the capacitance at each intersection is measured while the impedance circuit is in a high impedance state, and the impedance circuit is in a low impedance state. A second measuring step for measuring the capacitance at each intersection;
The touch panel device according to claim 1, wherein the operation of calculating the pressing force by the pressing force calculation circuit is performed after completion of the first measurement step and the second measurement step.   3. The capacitance detection circuit according to claim 2, wherein the capacitance detection circuit selects an intersection for performing measurement in a step to be executed later, based on a result of the step executed earlier in the first measurement step and the second measurement step. Touch panel device. The touch panel device according to claim 1, wherein the second insulator is a polarizing plate having an image display surface.

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