JP2023122376A - Switching device - Google Patents

Abstract

To determine on/off with high accuracy.SOLUTION: A switch device 1 includes an insulating base material 10, a movable electrode 20 having a displacement portion 21 which is arranged on an upper surface 11 side of the insulating base material 10 and is positionally displaceable with respect to the upper surface 11 of the insulating base material 10, a first electrode 30 and a second electrode 40 arranged at a position facing the movable electrode 20 on the upper surface 11 side of the insulating base material 10, and a control circuit 50 connected to each of the first electrode 30 and the second electrode 40. The first electrode 30 is arranged at a position facing the displacement portion 21. The second electrode 40 is arranged apart from the first electrode 30. The control circuit 50 applies a first potential to the first electrode 30 and applies a second potential different from the first potential to the second electrode 40 to detect variation of the capacitance value of the electrostatic capacitance between at least the first electrode 30 and the movable electrode 20, and further detect a state where the first electrode 30 and the movable 20 approach each other and further come into contact with each other, and on/off determination is performed based on these detection results.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to switch devices.

Conventionally, capacitive switching devices are known (see Patent Documents 1 to 3, for example).

Japanese Patent Application Laid-Open No. 2007-220473 Japanese Patent No. 5716135 Japanese Patent No. 6667077

However, the above-described conventional switch device has a problem that the accuracy of determination of ON/OFF of the switch is low.

Accordingly, the present disclosure provides a highly reliable switch device capable of determining on/off with high accuracy.

A switch device according to an aspect of the present disclosure includes an insulating base, a movable electrode disposed on an upper surface side of the insulating base and having a displacement portion capable of displacing a position with respect to the upper surface of the insulating base, the insulating A first electrode and a second electrode are arranged on the upper surface side of the substrate so as to face the movable electrode, and a control circuit is connected to each of the first electrode and the second electrode. The first electrode is arranged at a position facing the displacement portion. The second electrode is spaced apart from the first electrode. The control circuit applies a first potential to the first electrode and a second potential different from the first potential to the second electrode, so that at least the first electrode and the movable electrode are connected. It detects a change in the capacitance value of the capacitance between the first electrode and the movable electrode, further detects the state from proximity to contact between the first electrode and the movable electrode, and determines on/off based on these detection results. .

According to the present disclosure, it is possible to accurately determine ON/OFF and provide a highly reliable switch device.

FIG. 1 is a cross-sectional view showing the configuration (OFF) of the switch device according to Embodiment 1. FIG. FIG. 2 is a cross-sectional view showing the configuration (on) of the switch device according to the first embodiment. FIG. 3 is a graph showing the capacitance value and the reaction force applied to the operating body with respect to the pushing amount of the movable electrode. FIG. 4 is a cross-sectional view showing a state in which a foreign object is caught in the operating portion of the switch device according to Embodiment 1. FIG. FIG. 5 is a diagram showing a first example of a control circuit for the switch device according to the first embodiment. FIG. 6 is a diagram showing a second example of the control circuit of the switch device according to the first embodiment. FIG. 7A is a diagram showing the change over time of the potential of the first electrode during OFF in the second example of the control circuit of the switch device according to Embodiment 1. FIG. FIG. 7B is a diagram showing temporal changes in the potential of the first electrode in the second example of the control circuit of the switch device according to the first embodiment when the switch is turned on. 7C is a diagram showing temporal changes in the potential of the first electrode during a short circuit in the second example of the control circuit of the switch device according to Embodiment 1. FIG. FIG. 8 is a diagram showing a third example of the control circuit of the switch device according to the first embodiment. FIG. 9 is a diagram showing a fourth example of the control circuit of the switch device according to the first embodiment. FIG. 10 is a diagram showing a fifth example of the control circuit of the switch device according to the first embodiment. FIG. 11 is a diagram showing a modification of the fifth example of the control circuit of the switch device according to the first embodiment. 12 is a diagram showing a sixth example of the control circuit of the switch device according to the first embodiment. FIG. FIG. 13 is a diagram showing temporal changes in potentials of two terminals when the movable electrode and the first electrode are not in contact with each other in the sixth example of the control circuit of the switch device according to the first embodiment. FIG. 14 is a diagram showing temporal changes in potentials of two terminals when the movable electrode and the first electrode are in contact with each other in the sixth example of the control circuit of the switch device according to the first embodiment. 15 is a cross-sectional view showing a configuration of a switch device according to a modification of Embodiment 1. FIG. FIG. 16 is a cross-sectional view showing the configuration of the switch device according to the second embodiment. 17 is a cross-sectional view showing a configuration of a switch device according to Modification 1 of Embodiment 2. FIG. 18 is a cross-sectional view showing a configuration of a switch device according to Modification 2 of Embodiment 2. FIG. 19 is a cross-sectional view showing a configuration of a switch device according to Modification 3 of Embodiment 2. FIG. FIG. 20 is a cross-sectional view showing the configuration of the switch device according to the third embodiment. FIG. 21 is a flow chart showing the operation of the switch device according to the third embodiment. FIG. 22 is a perspective view of the switch device according to the example. FIG. 23 is an exploded perspective view of the switch device according to the embodiment. FIG. 24 is a perspective view of the first electrode and the second electrode of the switch device according to the example. FIG. 25 is a cross-sectional view showing the configuration of a switch device according to a modification of each embodiment.

(Findings on which this disclosure is based)
The inventors of the present invention have found that the conventional switch device described in the "Background Art" section has the following problems.

The switch devices disclosed in Patent Documents 1 and 2 detect changes in capacitance that occur between a person's finger and an electrode. However, the capacitance between the finger and the electrode depends on the moisture status of the finger, such as the presence or absence of perspiration, or whether the finger is dry or wet. In addition, the capacitance between the finger and the electrode also depends on the shape of the finger at the time of pressing or how it is pressed. For example, the amount of change in capacitance is different when pressing with the pad of the finger and when pressing with the tip of the finger. For this reason, the capacitance is not stable due to individual differences and state differences, so the accuracy of ON/OFF determination is lowered.

In addition, in the switch device disclosed in Patent Document 3, the displacement between the conductor and the switch electrode integrally interlocked with the push button via the elastic body, and between the conductor and the ground electrode, changes the respective capacities. The change affects the switch on/off capacitive measurement by the switch electrode. Therefore, the measured capacitance value is not stable depending on the pressing direction of the operator. As a result, the accuracy of ON/OFF determination is lowered.

Accordingly, the present disclosure provides a switch device capable of accurately determining ON/OFF.

For example, a switch device according to an aspect of the present disclosure includes an insulating base, a movable electrode disposed on an upper surface side of the insulating base and having a displacement portion capable of displacing a position with respect to the upper surface of the insulating base, a first electrode and a second electrode arranged at positions facing the movable electrode on the upper surface side of the insulating base; and a control circuit connected to each of the first electrode and the second electrode. Prepare. The first electrode is arranged at a position facing the displacement portion. The second electrode is spaced apart from the first electrode. The control circuit applies a first potential to the first electrode and a second potential different from the first potential to the second electrode, so that at least the first electrode and the movable electrode are connected. It detects a change in the capacitance value of the capacitance between the first electrode and the movable electrode, further detects the state from proximity to contact between the first electrode and the movable electrode, and determines on/off based on these detection results. .

Thereby, during charging, the potential of the movable electrode is fixed by capacitive coupling or electrical contact with the second electrode. For this reason, it is possible to suppress the influence of the capacitance with the operating body, the variation in the pressing direction, and the influence of noise from the outside. This makes it possible to determine on/off with high accuracy. In addition, since direct electrical connection to the movable electrode is not necessarily required, it is possible to eliminate the influence of defective conduction or short circuit of the movable electrode due to foreign matter such as dust. Therefore, the reliability of the switch device can be improved.

Further, for example, the control circuit may connect the second potential to a ground potential when charging the first electrode.

As a result, during charging, the potential of the movable electrode is fixed more strongly via the second electrode to which the ground potential is applied. Therefore, ON/OFF can be determined with higher accuracy.

Further, for example, the control circuit may connect the first potential to a ground potential during discharging from the first electrode.

As a result, the charged charge can be quickly discharged, and the period until the next sensing can be shortened. Therefore, a longer sensing scan time per unit time can be ensured, or the number of scans can be increased, thereby improving detection accuracy.

Also, for example, the movable electrode may have a first enlarged portion extending along the upper surface of the insulating base. The second electrode may be arranged at a position facing the first enlarged portion.

As a result, the capacitive coupling between the movable electrode and the second electrode can be strengthened, so that the potential of the movable electrode can be fixed more strongly. Therefore, ON/OFF can be determined with high accuracy. Moreover, when the movable electrode and the second electrode are in contact with each other, the contact area can be increased. Since the contact resistance between the movable electrode and the second resistor can be reduced, noise and power consumption caused by the resistance component can be reduced.

Further, for example, the movable electrode may generate a click feeling with respect to the operating body when the operating body pushes the displacement portion downward. The control circuit may make the determination when the click feeling is generated. Note that the term "at the time of occurrence of the click feeling" refers to a period from when the reaction force of the displacement portion to the operating body reaches a maximum value to when the first electrode comes closest to or touches the first electrode.

As a result, it is possible to set the ON/OFF determination at the time of the click feeling given to the operating body at the optimum timing, and it is possible to realize a switch device with good operability.

Further, for example, the second electrode may have a second enlarged portion extending outside the movable electrode in plan view. The area of the second enlarged portion may be equal to or larger than the area where the second electrode and the movable electrode overlap in plan view. The control circuit may detect a change in capacitance between the second electrode and the manipulation body, and detect the approach of the manipulation body based on the detection result.

Thereby, the approach of the operating body can be detected before the operating body pushes the displacement portion of the movable electrode. For example, the operation mode can be changed based on the detection result of the approach of the operating body.

Further, for example, the control circuit may detect the approach of the operating object in a state in which the first potential and the second potential are set to be equal to each other.

As a result, there is no charge transfer between the first electrode and the second electrode, so that the apparent capacitance component can be reduced to zero. The capacitance component between the first electrode and the second electrode becomes noise when detecting the approach of the operating body. In other words, since noise can be suppressed, it is possible to improve the detection accuracy of the second electrode that detects the proximity of the operating body.

Further, for example, the control circuit may have a detection mode for detecting the approach of the operating body and a determination mode for performing the determination. The detection mode may be switched to the determination mode when the approach of the operating body is detected in the detection mode. Also, for example, the scanning speed in the detection mode may be lower than the scanning speed in the determination mode.

Thereby, power consumption can be reduced in the detection mode. In the determination mode, it is possible to improve the accuracy of ON/OFF determination. By switching the operation mode based on the detection result of the approach of the operating object, it is possible to improve the accuracy of ON/OFF determination and reduce the power consumption.

Embodiments will be specifically described below with reference to the drawings.

It should be noted that the embodiments described below are all comprehensive or specific examples. Numerical values, shapes, materials, components, arrangement positions and connection forms of components, steps, order of steps, and the like shown in the following embodiments are examples, and are not intended to limit the present disclosure. Further, among the constituent elements in the following embodiments, constituent elements not described in independent claims will be described as optional constituent elements.

Each figure is a schematic diagram and is not necessarily strictly illustrated. Therefore, for example, scales and the like do not necessarily match in each drawing. Moreover, in each figure, substantially the same configurations are denoted by the same reference numerals, and overlapping descriptions are omitted or simplified.

Also, in this specification, terms that indicate the relationship between elements such as parallel or perpendicular, terms that indicate the shape of elements such as circular, and numerical ranges are not expressions that express only strict meanings, but substantial It is an expression that means that a difference of approximately several percent is also included, for example, a range equivalent to each other.

Also, in this specification, the terms “upper” and “lower” do not refer to the upward (vertically upward) and downward (vertically downward) directions in absolute spatial recognition, but rather to the relative position of each electrode. Used as a term defined by a relationship. Specifically, with respect to the insulating substrate, the side on which the movable electrode, the first electrode and the second electrode are arranged is referred to as "upper" or "upper", and the opposite side is referred to as "lower" or "lower". there is Also, the terms "above" and "below" are used not only when two components are spaced apart from each other and there is another component between the two components, but also when two components are spaced apart from each other. It also applies when two components are in contact with each other and are placed in close contact with each other.

In addition, in this specification and drawings, x-axis, y-axis and z-axis indicate three axes of a three-dimensional orthogonal coordinate system. The direction orthogonal to the main surface of the insulating base is taken as the z-axis direction.

In addition, in this specification, ordinal numbers such as “first” and “second” do not mean the number or order of constituent elements unless otherwise specified, so as to avoid confusion between constituent elements of the same kind and to distinguish between them. It is used for the purpose of

(Embodiment 1)
[composition]
First, the configuration of the switch device according to Embodiment 1 will be described with reference to FIGS. 1 and 2. FIG. FIG. 1 is a cross-sectional view showing an off state of a switch device 1 according to this embodiment. FIG. 2 is a cross-sectional view showing the ON state of the switch device 1 according to the present embodiment.

As shown in FIGS. 1 and 2, the switch device 1 is switched on/off by pushing the movable electrode 20 with the operation body 90 . OFF is a state in which the amount of pressing of the movable electrode 20 by the operating body 90 is less than the threshold. ON is a state in which the amount of pressing of the movable electrode 20 by the operating body 90 is equal to or greater than the threshold.

The operating body 90 is, for example, a human finger, but is not limited to this. The operating body 90 may be a rod-shaped member such as a touch pen or a block-shaped member having a predetermined shape. The operating body 90 may be an insulator.

As shown in FIGS. 1 and 2, the switch device 1 includes an insulating substrate 10, a movable electrode 20, a first electrode 30, a second electrode 40, and a control circuit 50. FIG.

The insulating base material 10 is a plate-like member having insulating properties. For example, the insulating base material 10 is a resin sheet or resin film formed using an insulating resin. Insulating substrate 10 has a top surface 11 and a bottom surface 12 . The upper surface 11 and the lower surface 12 are surfaces parallel to each other, for example.

The movable electrode 20 is arranged on the upper surface 11 side of the insulating base material 10 . The movable electrode 20 has a displacement portion 21 . The displacement part 21 is a part whose position relative to the upper surface 11 of the insulating base material 10 can be displaced. The displacement portion 21 changes its position when it is pushed into the operation body 90 .

In the present embodiment, the movable electrode 20 is formed in a dome shape that protrudes upward when the operating body 90 is not pressed. The movable electrode 20 is, for example, a metal dome made of metal. A displacement portion 21 is a portion of the movable electrode 20 that is the farthest from the upper surface 11 of the insulating base material 10 (specifically, the central portion in a plan view). An end of the movable electrode 20 is fixed to the second electrode 40 . As the displacement portion 21 is pushed by the operation body 90, the displacement portion 21 is gradually deformed, and when the reaction force value with respect to the pushing amount first exceeds the maximum value, the movable electrode 20 is reversed as shown in FIG. shape, and the pushed portion (displacement portion 21) is dented.

The movable electrode 20 generates a click feeling with respect to the operating body 90 when the operating body 90 pushes the displacement portion 21 downward. A click feeling is generated by a change in the reaction force that the movable electrode 20 gives to the operating body 90 with respect to the pressing force of the operating body 90 . The relationship between the pushing amount and the reaction force will be explained later.

The first electrode 30 is arranged on the upper surface 11 side of the insulating base material 10 . Specifically, the first electrode 30 is a conductive thin film placed in contact with the upper surface 11 . The first electrode 30 is arranged at a position facing the displacement portion 21 of the movable electrode 20 . That is, at least a portion of the first electrode 30 overlaps the displacement portion 21 in plan view of the upper surface 11 or the lower surface 12 . When the displacement portion 21 is displaced, the first electrode 30 and the displacement portion 21 can be in electrical contact.

The capacitance value of the electrostatic capacitance C<b>1 between the first electrode 30 and the displacement portion 21 of the movable electrode 20 changes according to the displacement of the displacement portion 21 . Specifically, as the displacement portion 21 approaches the first electrode 30, the capacitance value of the electrostatic capacitance C1 increases. When the displacement portion 21 contacts the first electrode 30, the displacement portion 21 and the first electrode 30 are short-circuited.

The second electrode 40 is arranged on the upper surface 11 side of the insulating base material 10 . More specifically, second electrode 40 is a conductive thin film disposed in contact with upper surface 11 . The second electrode 40 is arranged at a position facing the movable electrode 20 away from the first electrode 30 . Specifically, the second electrode 40 is arranged at a fixed portion of the movable electrode 20 , that is, at a position facing the end portion of the movable electrode 20 . When the movable electrode 20 is fixed annularly along the outer shape in plan view, the second electrode 40 is annularly formed surrounding the first electrode 30 . In this embodiment, the second electrode 40 and the movable electrode 20 are in contact with each other.

Therefore, by applying a predetermined potential to the second electrode 40, the potential of the movable electrode 20 can be fixed. Specifically, it is possible to suppress the potential of the movable electrode 20 from fluctuating depending on the state of the operating body 90 .

Each of the first electrode 30 and the second electrode 40 is a conductive thin film formed using a metal material such as silver or copper. The first electrode 30 and the second electrode 40 may be formed using conductive carbon or the like. The first electrode 30 and the second electrode 40 can be formed by printing, vapor deposition, sputtering, adhesion of a rolled metal thin film, or the like.

A control circuit 50 is connected to each of the first electrode 30 and the second electrode 40 . The control circuit 50 applies a first potential to the first electrode 30 and a second potential to the second electrode 40 . The first potential and the second potential are, for example, different potentials. As described above, the potential of the movable electrode 20 is fixed by applying the second potential to the second electrode 40 . The potential difference between the first electrode 30 and the movable electrode 20 can create a charge/discharge situation between the first electrode 30 and the movable electrode 20 . For example, the control circuit 50 connects the second potential to the ground potential when charging the first electrode 30 . Also, the control circuit 50 connects the first potential to the ground potential when discharging from the first electrode 30 .

The control circuit 50 detects a change in the charge/discharge amount associated with a change in the capacitance C1, thereby detecting a state from approach to contact between the first electrode 30 and the displacement portion 21 of the movable electrode 20. , ON/OFF (on or off) is determined based on the detection result. Specific determination processing will be described later.

The control circuit 50 is realized by, for example, an LSI (Large Scale Integration), which is an integrated circuit (IC). Note that the integrated circuit is not limited to an LSI, and may be a dedicated circuit or a general-purpose processor. The control circuit 50 is implemented, for example, by a microcontroller. Specifically, the control circuit 50 includes a nonvolatile memory storing a program, a volatile memory serving as a temporary storage area for executing the program, an input/output port, a processor executing the program, and the like. I'm in. The control circuit 50 may be a programmable FPGA (Field Programmable Gate Array) or a reconfigurable processor in which connection and setting of circuit cells in the LSI can be reconfigured. The functions executed by the control circuit 50 may be realized by software or by hardware.

1 and 2, the control circuit 50 is illustrated as a functional block rather than as a cross section of a physical configuration. The control circuit 50 is fixed to the insulating substrate 10, for example. Alternatively, the control circuit 50 may be housed inside a housing (not shown) housing the insulating base 10, or may be attached to the outer surface thereof.

[motion]
Next, the operation of the switch device 1 according to this embodiment will be described with reference to FIG.

FIG. 3 is a graph showing the capacitance value and the reaction force applied to the operation body 90 with respect to the pushing amount of the movable electrode 20. As shown in FIG. The horizontal axis of FIG. 3 represents the pushing amount of the movable electrode 20, that is, the amount of displacement of the displacement portion 21. As shown in FIG. The state where the pushing amount is 0 mm corresponds to the state shown in FIG. 1, and the pushing amount end point corresponds to the state shown in FIG. The vertical axis on the left side of FIG. 3 is the capacitance value of the electrostatic capacitance C1 between the movable electrode 20 and the first electrode 30. As shown in FIG. The vertical axis on the right side of FIG. 3 represents the reaction load applied to the operating body 90 by the movable electrode 20 .

As shown by the dashed line graph in FIG. 3, the reaction force applied to the operating body 90 increases as the amount of depression increases, reaches a maximum (peak) immediately before the shape is reversed, and decreases toward a minimum value after the shape is reversed. Become. For this reason, the operation body 90 receives a click feeling during the period from when the reaction force reaches its peak until it comes closest to or touches the first electrode 30 . It is desirable to determine whether the switch device 1 is on or off at an appropriate timing within the period during which the click feeling is generated. In the present embodiment, the control circuit 50 is turned on/off during the click feeling generation period, that is, the period from when the maximum reaction force load point is exceeded until the displacement portion 21 comes closest to or touches the first electrode 30 . judgment is made. Specifically, as shown in FIG. 3, the ON/OFF judgment area is set to the area from the amount of pushing when the reaction force reaches its peak to the end point of the amount of pushing. there is The end point of the pushing amount corresponds to the maximum pushing amount, for example, the pushing amount when the displacement portion 21 comes into contact with the first electrode 30 (see FIG. 2).

Further, when the pushing amount is maximized, that is, when the displacement portion 21 is in contact with the first electrode 30, the movable electrode 20 and the first electrode 30 are electrically connected. Since the first electrode 30 and the second electrode 40 are short-circuited, the control circuit 50 can determine whether the switch is on or off by detecting this short-circuit.

Depending on the type of the movable electrode 20, after the reaction force reaches its peak, the reaction force may not only gradually decrease to the maximum value of the pushing amount, but also may increase near the maximum pushing amount. be. In either case, ON/OFF determination is possible based on the capacitance value of the capacitance C1.

On the other hand, as shown in FIG. 4, there is a possibility that foreign matter 91 such as dust may enter between the first electrode 30 and the movable electrode 20 for some reason. When the foreign matter 91 is insulating, even if the operating body 90 pushes the displacement portion 21 , the foreign matter 91 is sandwiched and the first electrode 30 and the displacement portion 21 do not come into contact with each other. Therefore, there may be a case where the first electrode 30 and the movable electrode 20 are not short-circuited, and it is impossible to determine whether the switch is on or off.

In contrast, in the present embodiment, the control circuit 50 calculates the capacitance value of the electrostatic capacitance C1 between the first electrode 30 and the movable electrode 20 based on the amount of charge flowing into the first electrode 30. Then, on/off determination is performed based on the calculated capacitance value of the electrostatic capacitance C1. For example, the control circuit 50 compares the calculated capacitance value of the capacitance C1 with a predetermined threshold value, and determines that the capacitance value of the capacitance C1 is turned on when the capacitance value of the capacitance C1 is greater than the threshold value. The control circuit 50 determines that it is not turned on (off) when the capacitance value of the capacitance C1 is smaller than the threshold. As a result, even if the first electrode 30 and the movable electrode 20 do not come into contact with each other due to the intrusion of the foreign matter 91, it is possible to perform ON/OFF determination based on the change in the capacitance C1.

Moreover, although the second electrode 40 and the movable electrode 20 are in contact with each other in this embodiment, a space may be provided between the second electrode 40 and the movable electrode 20 . In this case, the foreign matter 91 may enter between the second electrode 40 and the movable electrode 20 . Even if the second electrode 40 and the movable electrode 20 do not come into contact with each other due to the intrusion of the foreign matter 91, it is possible to make ON/OFF determination based on the change in the capacitance C1.

As shown in the solid line graph in FIG. 3, as the pushing amount increases, the displacement portion 21 approaches the first electrode 30, so the capacitance value of the capacitance C1 increases. A threshold for ON/OFF determination is set in the ON/OFF determination area. Specifically, the threshold value is set to be equal to or greater than the capacitance value (approximately 7.5×10 ⁻¹² ) at the pressing amount (approximately 0.27) at which the reaction force peaks, and the maximum possible capacitance value of the electrostatic capacitance C1. It is set within a range of a value (approximately 3.4×10 ⁻¹¹ ) or less. By setting the threshold to a value close to the lower limit of the range, it is possible to make an ON determination at an early point in the period during which the operating body 90 receives the click feeling. Therefore, the switch operation can be performed with less delay in response to the operation. On the other hand, when the threshold value is set to a value close to the upper limit of the range, the time required for the reaction increases compared to the setting, but the on/off determination is based on the variation in the capacitance value of the capacitance C1. A decrease in accuracy can be suppressed. In this way, by setting the threshold value, it becomes possible to control the timing of turning on the switch at will, and it is possible to implement a switch operation with a better operational feel.

In this embodiment, the control circuit 50 repeats charging and discharging of the capacitance C1 between the movable electrode 20 and the first electrode 30 . During charging, the control circuit 50 applies a potential lower than the potential applied to the first electrode 30 to the second electrode 40 . For example, during charging, the control circuit 50 applies a ground potential to the second electrode 40 and applies a predetermined potential different from the ground potential to the first electrode 30 . When the displacement portion 21 of the movable electrode 20 is pushed during charging, the capacitance value of the electrostatic capacitance C1 increases, so the amount of charge flowing into the first electrode 30 also increases. The control circuit 50 measures the amount of change in the amount of charge flowing into the first electrode 30 caused by the change in the capacitance C1 during charging.

The control circuit 50 discharges after the charging period. Specifically, the control circuit 50 applies the ground potential to the first electrode 30 during discharging.

In this embodiment, during charging, the potential of the movable electrode 20 is fixed via the second electrode 40 to which a potential lower than the potential applied to the first potential 30 is applied. Therefore, the capacitance with the operating body 90 and the influence of noise from the outside can be suppressed. This makes it possible to determine on/off with high accuracy.

As described above, in the switch device 1 according to the present embodiment, it is possible to detect a short circuit due to electrical contact between the movable electrode 20 and the first electrode 30, and to perform ON/OFF determination at appropriate timing. It can be carried out. Further, even if a short circuit cannot be detected due to factors such as the foreign matter 91, it is possible to perform on/off determination based on the capacitance value of the electrostatic capacitance C1. In addition to judging ON/OFF based only on changes in the capacitance value, it is also possible to detect short circuits, resulting in high robustness and reliability, as well as excellent operability due to the flexibility of ON/OFF timing settings. The switch device 1 can be realized.

A specific operation example of the switch device 1 according to the present embodiment will be described below. As a parameter representing the capacitance value of the electrostatic capacitance C1 described above, the amount of charge flowing into the first electrode 30, the time required for charge to be accumulated in the first electrode 30, or the like can be used.

<First example>
First, the first example will be explained with reference to FIG.

FIG. 5 is a diagram showing a first example of a control circuit of the switch device 1 according to this embodiment. The control circuit shown in FIG. 5 includes a clock oscillator 51a that generates a control base signal for switching timing of switches SW1 and SW2, switches SW1, SW2 and SW3, a tank capacitor Cmod for supplying electric charge, and current sources IDAC1 and IDAC2. A drive unit 50a including

Note that FIG. 5 equivalently represents the first electrode 30 and the movable electrode 20 of the switch device 1 as a parallel circuit of the variable capacitor C and the switch SW. The variable capacitance C is changed (increased) by pressing the displacement portion 21 with the operation body 90 , and the switch SW is turned on by the contact between the first electrode 30 and the displacement portion 21 . In FIG. 5, illustration of the second electrode 40 is omitted.

The clock oscillator 51a exclusively turns on/off the switches SW1 and SW2 by supplying a clock signal to each of the switches SW1 and SW2. Switches SW1 and SW2 and variable capacitance C implement a switched capacitor resistance.

A tank capacitor Cmod is connected to the variable capacitor C via a switch SW1 so as to supply a charge corresponding to the capacitance value. Charge is supplied to the tank capacitor Cmod through current sources IDAC1 and IDAC2. A switch SW3 is connected between the current source IDAC2 and the tank capacitor Cmod. The switch SW3 is switched on/off according to a change in the charge amount of the variable capacitor C, and charges are supplied to the tank capacitor Cmod. When the displacement portion 21 is pushed by the operating body 90, the variable capacitance C changes (increases), and the amount of charge flowing into the variable capacitance C changes (increases). The detection voltage Vdet varies depending on the size of the variable capacitor C. FIG.

The control circuit according to the first example detects the amount of charge flowing into the variable capacitor C based on changes in the detection voltage Vdet. For example, the amount of charge flowing into the variable capacitor C increases as the capacitance value of the variable capacitor C increases. The control circuit can determine ON by comparing the amount of charge with a predetermined threshold value when the amount of charge is greater than the threshold value.

Note that when the first electrode 30 and the displacement portion 21 are in contact with each other, the first electrode 30 and the second electrode 40 connected to the ground potential are electrically connected via the movable electrode 20 . The amount of charge flowing into the first electrode 30 exceeds the threshold, and it can be determined that the electrode is on.

In this example, even if the contact between the first electrode 30 and the displacement portion 21 becomes impossible due to the foreign matter 91 or the like, the displacement portion 21 and the first electrode 30 approach each other, so that the capacitance value of the variable capacitor C increases. increases, the amount of charge flowing into the first electrode 30 increases. Therefore, ON/OFF can be determined by comparing the charge amount and the threshold value.

<Second example>
Next, a second example will be described with reference to FIG.

FIG. 6 is a diagram showing a second example of the control circuit of the switch device 1 according to this embodiment. The control circuit shown in FIG. 6 comprises a driver 50b including two comparators 51b and 52b and an SR flip-flop circuit (also called latch circuit) 53b.

The two comparators 51b and 52b are operational amplifiers each having a non-inverting input terminal (+), an inverting input terminal (-) and an output terminal. A reference voltage is applied to each of the two non-inverting input terminals. The two inverting input terminals are connected together and connected to the first electrode 30 of the switch device 1 . The two output terminals are respectively connected to the S terminal and R terminal of the SR flip-flop circuit 53b. The signal output from the comparator 51b and input to the S terminal is inverted. A Q' terminal of the SR flip-flop circuit 53b is connected to the first electrode 30 via a resistor R. Note that Q' means the inversion of Q.

The drive unit 50b shown in FIG. 6 repeats charging and discharging of the variable capacitance C as shown in FIGS. 7A to 7C. 7A to 7C are diagrams showing temporal changes in the potential of the first electrode 30 during operation of the second example of the control circuit of the switch device 1 according to the present embodiment. Specifically, FIG. 7A shows the change over time of the potential of the first electrode 30 when turned off (when not operated). FIG. 7B shows the change over time of the potential of the first electrode 30 during ON (pressing). FIG. 7C shows temporal changes in the potential of the first electrode 30 when the first electrode 30 and the movable electrode 20 are short-circuited.

The control circuit according to the second example performs ON/OFF determination by counting the number of times the potential of the first electrode 30 rises within a certain period. As can be seen by comparing FIGS. 7A and 7B, as the variable capacitance C (electrostatic capacitance between the first electrode 30 and the movable electrode 20) increases due to pressing by the operating body 90, the rising time becomes longer. Therefore, the number of rising times within a certain period of time decreases as the variable capacitance C increases. Therefore, by comparing the number of rising times with a predetermined threshold, the control circuit can determine ON when the number of rising times is less than the threshold.

Note that the variable capacitor C is not charged when the first electrode 30 and the displacement portion 21 are in contact with each other. Therefore, as shown in FIG. 7C, the potential of the first electrode 30 is constant and does not change. Since the count of the number of rising times does not increase, it falls below the threshold value, and ON can be determined.

In this example, even if the contact between the first electrode 30 and the displacement portion 21 becomes impossible due to a factor such as the foreign object 91, the potential of the first electrode 30 is increased by bringing the displacement portion 21 and the first electrode 30 closer to each other. rise time is longer. Therefore, by counting the number of rising times within a certain period, ON/OFF can be determined.

<Third example>
Next, a third example will be described with reference to FIG.

FIG. 8 is a diagram showing a third example of the control circuit of the switch device 1 according to this embodiment. The control circuit shown in FIG. 8 comprises a drive section 50c including a drive buffer 51c, a slope drive section 52c, a comparator 53c, switches SW3 and SW4, a sample capacitor Cs, and a slope resistor Rs. The driving section 50c is also called a dual slope circuit.

The drive buffer 51c supplies the first electrode 30 with a logic pulse for drive. The first electrode 30 is driven as a digital burst of logic pulses. As the displacement portion 21 of the movable electrode 20 is pushed by the operating body 90 and the displacement portion 21 approaches the first electrode 30, capacitive coupling between the movable electrode 20 (second electrode 40) and the first electrode 30 increases. Therefore, the charge generated in the second electrode 40 is accumulated in the sample capacitor Cs through the capacitive coupling. The charge accumulated in the sample capacitor Cs is accumulated and held by the switches SW3 and SW4 of the driving section 50c in synchronization with the driving logic pulse.

After the burst of logic pulses is completed, the charge stored on sample capacitor Cs is converted using slope resistor Rs which is driven high by slope driver 52c. Specifically, one end of the slope resistor Rs (connection point with the comparator 53c) monotonically increases from a negative potential according to the amount of charge accumulated in the sample capacitor Cs. The comparator 53c outputs a comparison result between the potential at one end of the slope resistor Rs and a predetermined potential Vss.

Based on the result of comparison by the comparator 53c, the time from when the potential at one end of the slope resistor Rs starts to increase until it reaches the zero crossing point is detected. The time depends on the charge accumulated in the sample capacitor Cs, and becomes longer as the amount of accumulated charge increases. The amount of charge accumulated in the sample capacitor Cs increases as the amount of depression of the operating body 90 increases. That is, the greater the amount of depression by the operating body 90, the longer the time required to reach the zero cross point. Therefore, the control circuit according to the third example can perform ON/OFF determination by comparing the time until reaching the zero crossing point with the threshold value.

Note that when the first electrode 30 and the displacement portion 21 are in contact with each other, the first electrode 30 and the second electrode 40 are electrically connected, so that the charge supplied from the driving buffer 51c is applied to the sample capacitor Cs. stored as is. Therefore, the amount of charge accumulated in the sample capacitor Cs increases, and the time required to reach the zero-crossing point exceeds the threshold, so that ON can be determined.

In this example, even if the contact between the first electrode 30 and the displacement portion 21 becomes impossible due to the foreign matter 91 or the like, the displacement portion 21 and the first electrode 30 approach each other, so that the capacitance value of the variable capacitor C increases. increases, the amount of charge stored in the sample capacitor Cs increases. For this reason, it takes a long time to reach the zero-crossing point, so it is possible to make ON/OFF determination.

<Fourth example>
Next, a fourth example will be described with reference to FIG. 9 .

FIG. 9 is a diagram showing a fourth example of the control circuit of the switch device 1 according to this embodiment. The control circuit shown in FIG. 9 includes a microcontroller 50d.

The microcontroller 50d has an internal sample-and-hold capacitor Cs (not shown). A first electrode 30 is connected to an input terminal IN of the microcontroller 50d via a resistor Rs.

The variable capacitance C between the movable electrode 20 and the first electrode 30 is connected in parallel with the sample-and-hold capacitance Cs in the microcontroller 50d with a time lag. First, after charging the variable capacitor C, the charge flows until it is connected to the sample-and-hold capacitor Cs and proportionally distributed between the two capacitors. The microcontroller 50d digitizes the voltage across the sample and hold capacitor Cs and stores it as a first voltage value.

Then, after charging the sample-and-hold capacitor Cs, the charge flows until it is proportionally distributed between the two capacitors connected to the variable capacitor C. The microcontroller 50d digitizes the voltage across the sample and hold capacitor Cs and stores it as a second voltage value.

The microcontroller 50d calculates the average value of the first voltage value and the second voltage value. The average value over a certain long period of time can be regarded as a reference value (threshold value) in a normal state, that is, when there is no depression by the operating body 90 .

When the displacement portion 21 of the movable electrode 20 is pushed by the operating body 90, the capacitance value of the variable capacitor C increases. This affects the amount of charge shared between the two capacitors. For example, when the variable capacitor C is precharged and shared with the sample-and-hold capacitor Cs, an increase in the capacitance value of the variable capacitor C increases the amount of charge transferred to the sample-and-hold capacitor Cs, thereby increasing the first voltage value. . When the sample-and-hold capacitor Cs is precharged and supplied to the variable capacitor C, the charge remaining in the sample-and-hold capacitor Cs is reduced and the second voltage value is reduced. However, since the increase in the first voltage value is large, the average value of the first voltage value and the second voltage value will increase. Therefore, since the average value of the first voltage value and the second voltage value increases when the displacement portion 21 is pushed by the operating body 90, the microcontroller 50d performs on/off determination by comparing it with the reference value. be able to.

Note that when the first electrode 30 and the displacement portion 21 are in contact with each other, the capacitance cannot be accumulated in the variable capacitance C. As shown in FIG. By detecting that the capacitance cannot be accumulated in the variable capacitor C, it is possible to determine whether the variable capacitor C is on.

In this example, even if the contact between the first electrode 30 and the displacement portion 21 becomes impossible due to the foreign matter 91 or the like, the displacement portion 21 and the first electrode 30 approach each other, so that the capacitance value of the variable capacitor C increases. increases, the amount of charge accumulated in the sample-and-hold capacitor Cs increases. Therefore, as the first voltage value increases, the average value of the first voltage value and the second voltage value also increases, so ON/OFF determination can be performed.

<Fifth example>
Next, a fifth example will be described with reference to FIG. 10 .

FIG. 10 is a diagram showing a fifth example of the control circuit of the switch device 1 according to this embodiment. The control circuit 50e shown in FIG. 10 includes a detection circuit 51e, a charging circuit 52e, and a calibration circuit 53e. The first electrode 30 is connected to the terminal 55e.

The detection circuit 51e is, for example, an integration circuit as shown in the drawing, and accumulates and outputs the input charges. Specifically, the detection circuit 51e is connected between the operational amplifier AMP1 whose non-inverting input terminal (+) is fixed to the initialization voltage V1, and the inverting input terminal (-) and the output terminal of the operational amplifier AMP1. a switch S1 capable of short-circuiting the integrating capacitor Cs1 to discharge and initialize it; and a switch S2 capable of controlling on/off of the connection between the inverting input terminal of the operational amplifier AMP1 and the terminal 55e. and including.

The charging circuit 52e includes a switch S3, an operational amplifier AMP2, and a switch S4 that controls on/off of the connection between the operational amplifier AMP2 and the terminal 55e. A voltage follower amplifier consisting of the switch S3 and the operational amplifier AMP2 constitutes a voltage source that supplies the voltage V3. By switching the switch S3, the voltage V3 is controlled to the initialization voltage V1 or the charging voltage V2 higher in potential than the initialization voltage V1.

The calibration circuit 53e includes a calibration capacitor Cc, a switch S5, and a current source 54e. The calibration capacitor Cc is connected between the terminal 55e and the output terminal of the operational amplifier AMP2. Current source 54e is connected to terminal 55e via switch S5. The other terminal of current source 54e is fixed at an arbitrary potential lower than charging voltage V2 and initialization voltage V1, such as ground potential Vss.

Next, an operation example of the control circuit shown in FIG. 10 will be described.

The variable capacitance C between the first electrode 30 and the movable electrode 20 is charged by the charging circuit 52e. During this charging period, the detection circuit 51e is also initialized at the same time. Specifically, at the first time, the switch S3 sets the power supply V3 to the charging voltage V2 higher than the initialization voltage V1, and the switch S4 is closed to charge the variable capacitor C to the potential V2 through the terminal 55e. be done. Similarly, at the first time, the switch S2, which is the input to the detection circuit 51e, is opened to cut off the input, and the switch S1 is closed to short-circuit and discharge the integration capacitor Cs1 for initialization, and the output VOUT is It is initialized to the initialization voltage V1. At this time, the switch S5 is opened and the current source 54e is disconnected from the terminal 55e. Also, the calibration capacitor Cc is short-circuited by the switch S4 and no charge is stored. At a second time after the first time, the switch S4 is opened to finish charging the variable capacitor C, and the switch S1 is opened to finish the initialization of the detection circuit 51e.

During the discharge period after the charge period, the power supply V3 is set to the initialization voltage V1 by the switch S3, and charges flow from the variable capacitor C into the calibration capacitor Cc. Specifically, during the period from the second time to the third time, the switch S5 is closed, the current source 54e is connected to the terminal 55e, and a constant amount of charge is extracted from the variable capacitor C. At this time, the amount of charge extracted is defined by the product of the current value of the current source 54e and the period from the second time to the third time.

During the period from the third time to the fourth time, the switch S2 is closed and the charge from the variable capacitor C is also input to the detection circuit 51e. Since the detection circuit 51e includes an operational amplifier AMP1 virtually grounded to the initialization voltage V1 as shown in FIG. go. The charge input to the detection circuit 51e is cumulatively added (integrated) to the integration capacitor Cs1, and the output VOUT changes (decreases).

After that, the charging period and the discharging period are repeated. The charge input to the detection circuit 51e is cumulatively added (integrated) to the integration capacitor Cs1. The amount of charge discharged from the variable capacitor C is C×(V2−V1). A portion of this is drawn by the current source 54e in the first half of the discharge period, another portion is consumed to charge the calibration capacitor Cc in the second half of the discharge period, and the rest is input to the detection circuit 51e. . If the sum of the amount of charge drawn by the current source 54e and the amount of charge consumed to charge the calibration capacitor Cc can be made the same as the capacitance value of the variable capacitor C when not depressed, the detection circuit 51e The amount of charge input to can be only the amount of charge corresponding to the capacitance value increased by pressing. Thereby, ON/OFF can be determined efficiently.

Note that when the first electrode 30 and the displacement portion 21 are in contact with each other, the capacitance cannot be accumulated in the variable capacitance C. As shown in FIG. That is, the potential of the terminal 55e becomes the potential of the second electrode 40 (specifically, the ground potential). Therefore, the integral capacitance Cs1 of the detection circuit 51e becomes a constant value. By detecting this, the on state can be determined.

FIG. 11 is a diagram showing another example of the fifth example of the control circuit of the switch device 1 according to this embodiment. The control circuit 50f shown in FIG. 11 includes a detection circuit 51e, a discharge circuit 52f, and a calibration circuit 53f. The first electrode 30 is connected to the terminal 55e.

Detecting circuit 51e and discharging circuit 52f are similar to detecting circuit 51e and charging circuit 52e shown in FIG. Note that the discharge circuit 52f is different in that the charging voltage V2 is controlled to the initialization voltage V1 or a voltage V4 lower than the initialization voltage V1 by switching the switch S3. Although the circuit configuration is substantially the same as that of the charging circuit 52e, it is referred to as the discharging circuit 52f because the charge moves in the opposite direction.

The calibration circuit 53f includes a calibration capacitor Cc, a switch S5, and a current source 54f. A calibration capacitor Cc is connected between the terminal 55e and the operational amplifier AMP2, as in FIG. The current source 54f is connected to, for example, the power supply VDD via the switch S5. The voltage value of the power supply VDD is higher than the charging voltage V4 or the initialization voltage V1.

The control circuit 50f shown in FIG. 11 can also determine ON/OFF by the same control as the control circuit 50e shown in FIG. Since the control circuit 50f has a discharge circuit 52f and the flow of charge is reversed, the change in the output VOUT of the detection circuit 51e increases.

<6th example>
Next, a sixth example will be described with reference to FIG. 12 .

FIG. 12 is a diagram showing a sixth example of the control circuit of the switch device 1 according to this embodiment. One end of the resistor R is connected to the first electrode 30 in the control circuit shown in FIG. Both ends of resistor R are connected to terminals 51g and 52g, respectively. The control circuit determines ON/OFF based on the rising time of each signal of the terminal 52g when a predetermined pulse voltage is applied to the terminal 51g.

FIG. 13 is a diagram showing temporal changes in the potentials of the two terminals 51g and 52g when the movable electrode 20 and the first electrode 30 are not in contact with each other in this example. Vin represents the time change of the potential of the terminal 51g. Vout represents the time change of the potential of the terminal 52g.

As shown in FIG. 13, when a pulse voltage is applied to the terminal 51g, the rise of the potential of the terminal 52g is delayed by the RC parallel circuit of the resistor R and the variable capacitor C. As shown in FIG. As the variable capacitance C increases due to the pressing of the displacement portion 21 by the operating body 90, the time required for rising becomes longer. For example, the control circuit can set a predetermined threshold time T and determine that the terminal 52g is on when the potential of the terminal 52g has not risen completely after the set threshold time T has elapsed.

When the movable electrode 20 and the first electrode 30 are brought into contact with each other by pushing the displacement portion 21 with the operating body 90, the terminal 52g is electrically connected to the movable electrode 20 (the second electrode 40) via the switch SW. Therefore, as shown in FIG. 14, the potential of the terminal 52g is maintained at a constant value (for example, 0V) without rising. Note that FIG. 14 is a diagram showing temporal changes in the potentials of the two terminals 51g and 52g when the movable electrode 20 and the first electrode 30 are in contact with each other in this example. In this case also, even if the threshold time T has passed, the potential of the terminal 52g does not rise, so the control circuit can be determined to be on.

In this example, even if the contact between the first electrode 30 and the displacement portion 21 becomes impossible due to the foreign matter 91 or the like, the displacement portion 21 and the first electrode 30 approach each other, so that the capacitance value of the variable capacitor C increases. increases, the rise of the potential of the terminal 52g slows down. Therefore, by comparing with the threshold time T, ON/OFF can be determined.

[Modification]
Next, a modified example of Embodiment 1 will be described with reference to FIG. 15 . FIG. 15 is a cross-sectional view showing the configuration of a switch device 2 according to this modification.

As shown in FIG. 15, the switch device 2 is different from the switch device 1 shown in FIG. differ. The following description focuses on the differences from the first embodiment, and omits or simplifies the description of the common points.

The flexible film 60 is a film member having an upwardly convex dome-shaped portion. A movable electrode 20a along the dome shape is provided on the lower surface (rear surface) of the dome-shaped portion.

The movable electrode 20 a is a conductive layer provided on the bottom surface of the flexible film 60 . As in the first embodiment, it is formed in an upwardly convex dome shape. For example, the movable electrode 20a is formed by applying a metal material such as silver by printing or the like.

The end portion of the movable electrode 20 a that faces the second electrode 40 is in contact with the second electrode 40 . Thereby, the potential of the movable electrode 20a can be fixed.

Note that the movable electrode 20a and the second electrode 40 do not have to be in contact with each other. In this case, the capacitance value of the electrostatic capacitance C2 between the movable electrode 20a and the second electrode 40 is substantially fixed. This is because the portion of the movable electrode 20a facing the second electrode 40 (the end portion of the movable electrode 20a) is not substantially displaced. By applying a predetermined potential to the second electrode 40, capacitive coupling between the movable electrode 20a and the second electrode 40 can fix the potential of the movable electrode 20a. In other words, it is possible to prevent the potential of the movable electrode 20a from fluctuating due to the depression of the operating body 90. FIG.

By pushing the dome-shaped portion of the flexible film 60 into the operation body 90, the shape of the dome-shaped portion is reversed. Thereby, the movable electrode 20a can achieve the same function as the movable electrode 20 according to the first embodiment.

The flexible film 60 has insulating properties. Even if an electric current flows through the movable electrode 20a for some reason, the electric current can be suppressed from flowing through the operating body 90. FIG. The flexible film 60 also functions as a protective member for the movable electrode 20a.

The adhesive layer 70 is an example of a member that fixes the flexible film 60 to the upper surface 11 of the insulating base material 10 . The adhesive layer 70 is formed by applying an adhesive or adhesive to the top surface 11 . Note that the means for fixing the flexible film 60 is not limited to the adhesive layer 70 .

In the switch device 2 as described above, similarly to the first embodiment, ON/OFF can be determined with high accuracy.

(Embodiment 2)
Next, Embodiment 2 will be described.

The switch device according to the second embodiment differs from the switch device according to the first embodiment in that the movable electrode has an enlarged portion extending along the upper surface of the insulating base. In the following, the description will focus on the differences from the first embodiment, and the description of the common points may be omitted or simplified.

[composition]
FIG. 16 is a cross-sectional view showing the configuration of the switch device 101 according to this embodiment. As shown in FIG. 16, the switch device 101 comprises a movable electrode 120 instead of the movable electrode 20 compared to the switch device 1 shown in FIG.

The movable electrode 120 has an enlarged portion 122 . The enlarged portion 122 is an example of a first enlarged portion extending along the upper surface 11 of the insulating base material 10 . For example, the enlarged portion 122 is annularly provided along the edge of the dome-shaped portion including the displacement portion 21 . The enlarged portion 122 is in contact with the second electrode 40 in plan view. That is, the enlarged portion 122 is provided so as to contact and cover at least a portion of the upper surface of the second electrode 40 .

Since the contact area between the enlarged portion 122 and the second electrode 40 is thus increased, the contact resistance is reduced. Thereby, noise and power consumption caused by the resistance component can be reduced.

Note that when the enlarged portion 122 and the second electrode 40 are not in contact with each other, the overlapping area of the enlarged portion 122 and the second electrode 40 in plan view increases. Therefore, the potential of the movable electrode 120 is strongly fixed by the contact between the enlarged portion 122 and the second electrode 40 over a large area. Therefore, the influence of noise can be suppressed, and the accuracy of ON/OFF determination can be improved.

[Modification 1]
Next, Modification 1 of Embodiment 2 will be described with reference to FIG.

FIG. 17 is a cross-sectional view showing the configuration of a switch device 102 according to this modification. As shown in FIG. 17, switch device 102 includes movable electrode 120a, flexible film 60 and adhesive layer 70 instead of movable electrode 120, as compared with switch device 101 shown in FIG.

Movable electrode 120a is a conductive layer provided on the lower surface (back surface) of the dome-shaped portion of flexible film 60, as in switch device 2 according to the modification of the first embodiment. The conductive layer extends outwardly along the edges of the dome-shaped portion as well as the portion. The enlarged portion of the conductive layer is the enlarged portion 122a.

Since the enlarged portion 122a is provided, the contact area between the enlarged portion 122a and the second electrode 40 is increased. Therefore, the contact resistance between the enlarged portion 122a and the second electrode 40 becomes low, and the noise and power consumption caused by the resistance component can be reduced. Further, the contact between the enlarged portion 122a and the second electrode 40 strongly fixes the potential of the movable electrode 120a. Since the shielding function of the movable electrode 120a is enhanced, the influence of noise can be suppressed, and the ON/OFF determination accuracy can be enhanced.

Note that the enlarged portion 122a and the second electrode 40 do not have to be in contact with each other. For example, the adhesive layer 70 may be arranged between the enlarged portion 122 a and the second electrode 40 . Even in this case, the capacitive coupling between the enlarged portion 122a and the second electrode 40 can fix the potential of the movable electrode 120a. Therefore, the influence of noise can be suppressed, and the accuracy of ON/OFF determination can be improved.

[Modification 2]
Next, Modification 2 of Embodiment 2 will be described with reference to FIG.

FIG. 18 is a cross-sectional view showing the configuration of a switch device 103 according to this modification. As shown in FIG. 18, switch device 103 comprises movable electrode 120b instead of movable electrode 120, compared to switch device 101 shown in FIG.

The movable electrode 120b includes a dome-shaped metal member 120c and a conductive layer 120d. The metal member 120c is, for example, a dome-shaped metal dome convex upward, and is the same as the movable electrode 20 of the first embodiment. 120 d of conductive layers are provided along the lower surface of the flexible film 60 like the modification 1 of Embodiment 2, and form the enlarged part 122a. The conductive layer 120d is in contact with the metal member 120c and electrically connected. That is, the conductive layer 120d and the metal member 120c have substantially the same potential.

In the example shown in FIG. 7, the conductive layer 120d is not provided on the top portion of the metal member 120c, specifically, on the displacement portion 21, but the present invention is not limited to this. The conductive layer 120d may be formed in a dome shape like the movable electrode 120a of the first modification of the second embodiment.

Also in the switch device 103 according to this modified example, similarly to the second embodiment, the enlarged portion 122a can strongly fix the potential of the movable electrode 120b. Therefore, the influence of noise can be suppressed, and the accuracy of ON/OFF determination can be improved.

[Modification 3]
Next, Modification 3 of Embodiment 2 will be described with reference to FIG.

FIG. 19 is a cross-sectional view showing the configuration of a switch device 104 according to this modification. As shown in FIG. 19, the switch device 104 comprises a movable electrode 120e instead of the movable electrode 120 compared to the switch device 101 shown in FIG.

The movable electrode 120e has a flat top portion (displacement portion 121e). The movable electrode 120 e has a displacement portion 121 e and an enlarged portion 122 . The displacement portion 121 e is positioned apart from the upper surface 11 of the insulating base 10 and is displaced with respect to the upper surface 11 when pushed into the operation body 90 .

In this modified example, the peak of the reaction force applied to the operating body 90 by the displacement portion 121e is substantially when the pushing amount of the displacement portion 121e is maximized. Therefore, the threshold value for ON/OFF determination can be set to, for example, the capacitance value of the electrostatic capacitance C1 when the pushing amount of the displacement portion 121e is maximized.

Also in the switch device 104 according to this modified example, the potential of the movable electrode 120e can be strongly fixed by the enlarged portion 122, as in the second embodiment. Therefore, the influence of noise can be suppressed, and the accuracy of ON/OFF determination can be improved.

(Embodiment 3)
Next, Embodiment 3 will be described.

The switch device according to the third embodiment differs from the switch device according to the modified example of the first embodiment in that the second electrode has an enlarged portion extending outside the movable electrode. In the following, the description will focus on the differences from the first embodiment, and the description of the common points may be omitted or simplified.

[composition]
FIG. 20 is a cross-sectional view showing the configuration of a switch device 201 according to this embodiment. As shown in FIG. 20, the switch device 201 comprises a second electrode 240 instead of the second electrode 40 compared to the switch device 1 shown in FIG. Switch device 201 also includes flexible film 60 and adhesive layer 70 .

Flexible film 60 and adhesive layer 70 are substantially the same as flexible film 60 and adhesive layer 70 according to the modification of the first embodiment, respectively. In this embodiment, the adhesive layer 70 is also provided between the flexible film 60 and the movable electrode 20 . Instead of the movable electrode 20, a movable electrode 20a according to the modification of the first embodiment may be provided. In addition, the flexible film 60 and the adhesive layer 70 are not essential components.

The second electrode 240 has an enlarged portion 241 . The enlarged portion 241 is an example of a second enlarged portion extending outside the movable electrode 20 in plan view. The enlarged portion 241 is used to detect the approach of the operating body 90 to the movable electrode 20 . The area of the enlarged portion 241 is greater than or equal to the area where the second electrode 240 and the movable electrode 20 overlap in plan view. The larger the area of the enlarged portion 241, the wider the detection range of the approach of the operating body 90 can be secured.

In switch device 201 according to the present embodiment, control circuit 50 has a plurality of operation modes. Specifically, the control circuit 50 has, as operation modes, a determination mode for determining ON/OFF and a detection mode for detecting the approach of the operating body 90 . Since the detection mode contributes to power saving as described later, it is also called a power saving mode. Since the determination mode is a normal operation of the switch device 201, it is also called a normal mode.

The scan speed in detection mode is slower than the scan speed in determination mode. Note that the scan speed is the number of repetitions of charging and discharging the capacitance C1 per unit time. In the determination mode with a high scanning speed, the number of charge/discharge repetitions per unit time increases, so highly accurate determination becomes possible. In the detection mode in which the scan speed is low, the number of charge/discharge repetitions per unit time is small, so power consumption can be reduced. Having the detection mode enables power saving of the switch device 201 .

In the detection mode, the control circuit 50 detects changes in the capacitance value of the electrostatic capacitance C3 generated between the second electrode 240 and the operating body 90. FIG. Specifically, the control circuit 50 repeatedly charges and discharges the electrostatic capacitance C3 between the second electrode 240 and the operating body 90 . During charging, the control circuit 50 applies a predetermined potential different from the ground potential to the second electrode 240 .

When the operating body 90 approaches the second electrode 240 during charging, the capacitance value of the electrostatic capacitance C3 between the second electrode 240 and the operating body 90 increases, so the amount of charge flowing into the second electrode 240 also increases. Become. The control circuit 50 measures changes in the amount of charge flowing into the second electrode 240 based on changes in the capacitance value of the electrostatic capacitor C3. That is, the charging period is the sensing period of the switch device 201, that is, the period during which the approach of the operating body 90 can be detected. The control circuit 50 compares the capacitance value of the electrostatic capacitance C3 with a predetermined threshold value for the operating tool 90, and determines that the approach of the operating tool 90 has been detected when the capacitance value of the electrostatic capacitance C3 is greater than the threshold value. do. The control circuit 50 determines that the operating body 90 is not approaching when the capacitance value of the electrostatic capacitance C3 is smaller than the threshold.

In sensing mode, the control circuit 50 discharges after a period of charging. Specifically, the control circuit 50 applies the ground potential to the second electrode 240 .

In the detection mode, the control circuit 50 may apply a fixed potential other than the ground potential to the first electrode 30 during charging. Alternatively, the control circuit 50 may put the first electrode 30 in a floating state without applying a potential to the first electrode 30 .

Also, the control circuit 50 may apply the same potential as the potential applied to the second electrode 240 to the first electrode 30 . Thereby, the apparent capacitance component between the first electrode 30 and the second electrode 240 can be canceled. The capacitance component is a noise component for the electrostatic capacitance C3 between the second electrode 240 and the operating body 90. Since this noise component can be reduced, the detection accuracy and sensitivity of the operating tool 90 can be enhanced.

[motion]
Next, the operation of switch device 201 according to the present embodiment will be described with reference to FIG. FIG. 21 is a flow chart showing the operation of the switch device 201 according to this embodiment.

As shown in FIG. 21, the control circuit 50 initially places the second electrodes 240 in the high-speed scan mode and operates the first electrodes 30 in the high-speed scan mode at least once (S10). Specifically, the control circuit 50 scans the second electrode 240 at a low speed. More specifically, the control circuit 50 repeats charging and discharging by applying a predetermined potential to at least one of the first electrode 30 and the second electrode 240, thereby controlling the amount of charge flowing into the second electrode 240 during charging. and the amount of change in the amount of charge flowing into the first electrode 30 are measured. The amount of charge flowing into each electrode can be measured using, for example, a scan interval. By operating the first electrode 30 in the high-speed scan mode at the start, even when the movable electrode 20 is pushed almost at the same time as the start, it is possible to perform ON/OFF determination with high accuracy.

It is desirable that the second electrode 240 is scanned at high speed at the start, but if only the first electrode 30 is scanned at high speed, the second electrode 240 does not necessarily need to be scanned at high speed.

If there is no reaction (No in S12), that is, if the capacitance value of the electrostatic capacitance C3 corresponding to the amount of charge flowing into the second electrode 240 is less than the threshold, the control circuit 50 shifts to the detection mode (S14). . In addition, when the detection mode is being executed, the detection mode is maintained as it is. In sensing mode, the first electrode 30 is operated in slow scan mode.

If there is a reaction (Yes in S12), that is, if the capacitance value of the electrostatic capacitance C3 corresponding to the amount of charge flowing into the second electrode 240 is equal to or greater than the threshold, the control circuit 50 shifts to determination mode (normal mode). do. In the determination mode according to the present embodiment, the approach of the operating body 90 and the on/off determination of the movable electrode 20 by the operating body 90 are performed.

Specifically, when there is a reaction (Yes in S12), the control circuit 50 scans the second electrode 240 at high speed (S16). Further, the control circuit 50 scans the first electrode 30 at high speed (S18). The scan speed for each of the second electrode 240 and the first electrode 30 is higher than the scan speed in sensing mode.

Note that it is not always necessary to scan the second electrode 240 at high speed. That is, step S16 may be omitted.

As long as the approach of the operating body 90 and the pressing of the operating body 90 against the movable electrode 20 are detected (Yes in S12), the determination mode is maintained. When the approach of the operating body 90 and the pressing of the operating body 90 against the movable electrode 20 are no longer detected (No in S12), the detection mode is shifted to the detection mode until the approach of the operating body 90 is detected again. is maintained.

As described above, in the switch device 201 according to the present embodiment, the control circuit 50 switches from the detection mode to the determination mode when the approach of the operating tool 90 is detected in the detection mode. That is, the control circuit 50 switches the scanning speed for the first electrode 30 from low speed to high speed. As a result, it is possible to accurately detect the operation on the movable electrode 20 and to accurately determine whether the electrode is on or off. In addition, when the approach of the operating body 90 is not detected, the scan speed is reduced, thereby reducing power consumption and contributing to energy saving.

In addition, although the example in which the second electrode 240 has the enlarged portion 241 is shown in the present embodiment, the present invention is not limited to this. The enlarged portion 241 may be separated from the portion of the second electrode 240 facing the movable electrode 20 . That is, the enlarged portion 241 does not have to be electrically connected to the second electrode 240 .

(Example)
Specific examples of the switch device according to each of the above embodiments will be described below with reference to FIGS. 22 to 24. FIG.

FIG. 22 is a perspective view of the switch device 301 according to this embodiment. FIG. 23 is an exploded perspective view of the switch device 301 according to this embodiment. FIG. 24 is a perspective view of the first electrode 330 and the second electrode 340 of the switch device 301 according to this embodiment.

As shown in FIG. 22, the switch device 301 has five switch units 302a, 302b, 302c, 302d and 302e. Each of the five switch portions 302a to 302e can be pushed by the operating body 90, and ON/OFF determination is made independently for each of them. For example, a different function is assigned to each switch unit. The five switch units 302a to 302e are arranged side by side in one direction, but may be arranged in a matrix, and the arrangement is not particularly limited. The number of switch units included in the switch device 301 is not limited to five, and may be one to four, or six or more.

As shown in FIG. 23, the switch device 301 includes an insulating substrate 310, five movable electrodes 320, five first electrodes 330, a second electrode 340, a flexible film 360, and an adhesive layer 370. , an electrode protection layer 380, an adhesive layer for attachment 385, and a connector connection terminal portion 390 (illustrated only in FIG. 22 and omitted in FIG. 23). The switch device 301 also includes a control circuit 50 (not shown). The movable electrodes 320 and the first electrodes 330 are provided in the same number as the number of switch units provided in the switch device 301 .

The insulating substrate 310 corresponds to the insulating substrate 10 described above. In this embodiment, the insulating base material 310 is configured in the shape of a rectangular flat plate, and as shown in FIG. 23, has an extended portion 313 extending in one direction from the flat plate portion. The extended portion 313 is a portion for providing wiring for electrically connecting the switch device 301 to another device. A connector connection terminal portion 390 and a reinforcing plate (not shown) are provided at the distal end of the extension portion 313 . The extending portion 313 may be flexible and bendable. Note that the extended portion 313 may not be provided.

The movable electrode 320 corresponds to the movable electrode 20 described above. The five movable electrodes 320 are covered with an adhesive layer 370 and fixed to the upper surface of the insulating base material 310 by the adhesive layer 370 . The movable electrode 320 may have an enlarged portion 122 like the movable electrode 120 shown in FIG. The planar shape of the movable electrode 320 is circular, but it may be square, rectangular, polygonal, or elliptical, and is not particularly limited.

The first electrode 330 corresponds to the first electrode 30 described above. In this embodiment, the five first electrodes 330 are electrically insulated from each other, and the amount of charge flowing into each can be individually detected. The planar shape of the first electrode 330 is circular, but may be square, rectangular, polygonal, oval, etc., and is not particularly limited. As shown in FIG. 24, the wiring 332 from each of the five first electrodes 330 extends to the tip portion of the extended portion 313 without contacting each other.

The second electrode 340 corresponds to the second electrode 40 described above. In this embodiment, the second electrode 340 is common to the five switch sections 302a-302e. The second electrode 340 is provided so as to surround each of the five first electrodes 330 . Focusing on each switch part, the second electrodes 340 of each switch part are electrically connected to each other by wiring 342 and controlled to have the same potential.

Moreover, in this embodiment, as shown in FIG. 24, the second electrode 340 has a mesh-like enlarged portion 341 . The enlarged portion 341 is provided on the upper surface of the insulating base material 310 so as to cover the portion where the five movable electrodes 320 are not provided.

The planar shape of the portion of the second electrode 340 excluding the enlarged portion 341 is an annular shape with a predetermined width, but may be a square, rectangular, polygonal annular shape, or elliptical annular shape, and is not particularly limited. . The second electrode 340 does not have to surround the first electrode 330 .

The flexible film 360 collectively covers the five movable electrodes 320, but is not limited to this. A flexible film 360 may be provided for each one or more movable electrodes 320 .

The adhesive layer 370 fixes the insulating base material 310 and the flexible film 360 by sandwiching the five movable electrodes 320 with the insulating base material 310 . In this embodiment, the adhesive layer 370 is separated into two, but it is not limited to this. The adhesive layer 370 is, for example, an adhesive sheet, but is not limited to this. The adhesive layer 370 may be formed by applying an adhesive to the flexible film 360 by printing.

The electrode protection layer 380 is provided on the upper surface side of the insulating base material 310 to protect the first electrode 330 and the second electrode 340 . Electrode protection layer 380 is provided between each of first electrode 330 and second electrode 340 and adhesive layer 370 . The electrode protection layer 380 is formed, for example, by applying an insulating resin material by a printing method or the like.

The electrode protection layer 380 is provided with openings 381 corresponding to the movable electrodes 320 one-to-one. The movable electrode 320 is positioned within the opening 381 and contacts the second electrode 340 exposed within the opening 381 . Note that the opening 381 may not be provided for each movable electrode 320 , and may be one continuous opening for five movable electrodes 320 .

The attachment adhesive layer 385 is an adhesive layer for attaching the switch device 301 to another member. For example, the mounting adhesive layer 385 is a double-sided tape, but is not limited to this. The mounting adhesive layer 385 may be formed by applying an adhesive to the electrode protection layer 380 by printing, for example.

The connector connection terminal portion 390 is provided at the tip portion of the extension portion 313 of the insulating base material 310 and used for electrical connection to other members. A reinforcing plate (not shown) may be provided to increase the strength of the distal end portion of the extended portion 313 . By providing the reinforcing plate, damage to the wiring can be suppressed.

(Other embodiments)
Although the switch device according to one or more aspects has been described above based on the embodiments, the present disclosure is not limited to these embodiments. As long as they do not deviate from the gist of the present disclosure, modifications that can be made by those skilled in the art to the present embodiment, and forms constructed by combining the components of different embodiments are also included within the scope of the present disclosure. be

For example, in Embodiment 3, an example in which the control circuit 50 detects the approach of the operation tool 90 using the enlargement unit 241 and changes the scan speed has been described, but the present invention is not limited to this. For example, the control circuit 50 may change the scan speed based on the amount of pressing of the displacement portion 21 of the movable electrode 20 by the operating body 90 . Specifically, the control circuit 50 may change the scanning speed based on the capacitance value of the electrostatic capacitance C<b>1 that increases according to the pressing amount of the displacement portion 21 .

As shown in FIG. 3, when the operating body 90 pushes the displacement portion 21, the capacitance value of the electrostatic capacitance C1 gradually increases before the reaction force reaches its peak. Therefore, the control circuit 50 may preset a second threshold smaller than the ON/OFF determination threshold (first threshold) as the threshold for changing the scanning speed. The control circuit 50 may change the scanning speed to a high speed when the capacitance value of the electrostatic capacitance C1 becomes larger than the second threshold. As a result, the scanning speed can be kept low when the displacement portion 21 is not pushed by the operating body 90, which contributes to energy saving.

Further, instead of changing the scanning speed, or in addition to changing the scanning speed, the control circuit 50 determines ON/OFF when the capacitance value of the electrostatic capacitor C1 becomes larger than the second threshold. A part of the processing to be operated according to the result may be started in advance. For example, if a predetermined image is to be displayed on the display when the switch device according to the present disclosure is turned on, reading of the image from the memory, processing of the read image, etc. are started in advance, and it is determined that it is on. The image may be immediately displayed on the display if requested. As a result, it is possible to shorten the reaction delay time of the process to the switch operation. It is more useful when high responsiveness is required, such as game controllers.

Further, for example, the operating body 90 does not need to be pushed into the movable electrode 20 by directly contacting it. For example, as shown in FIG. 25 , the operating body 90 may indirectly push the movable electrode 20 via a pusher 80 provided in the switch device 401 . The pusher 80 is supported by a support portion 81 so as to be vertically movable. The support portion 81 may be configured integrally with the insulating base material 10 . In the example shown in FIG. 25, since the enlarged portion 241 of the second electrode 240 is provided, the approach of the operating body 90 can be detected as in the third embodiment.

Further, one aspect of the present disclosure can be implemented as a control method for the switch device described above or a program that causes a computer to execute the control method. Alternatively, one aspect of the present disclosure can be implemented as a computer-readable non-temporary recording medium storing the program.

In addition, various changes, replacements, additions, and omissions can be made to each of the above-described embodiments within the scope of claims or equivalents thereof.

INDUSTRIAL APPLICABILITY The present disclosure can be used as a switch device that can accurately determine whether it is on or off, and can be used in various devices such as input devices, operation devices, and game controllers.

1, 2, 101, 102, 103, 104, 201, 301, 401 Switch device 10, 310 Insulating base material 11 Upper surface 12 Lower surface 20, 20a, 120, 120a, 120b, 120e, 320 Movable electrodes 21, 121e Displacement part 30 , 330 first electrodes 40, 240, 340 second electrodes 50, 50e, 50f control circuits 50a, 50b, 50c drive unit 50d microcontroller 51a clock oscillators 51b, 52b, 53c comparator 51c drive buffer 51e detection circuit 52c slope drive unit 52e charging circuit 52f discharging circuit 53b SR flip-flop circuits 53e, 53f calibration circuits 54e, 54f current source 55e terminals 60, 360 flexible film 70 adhesive layer 80 pusher 81 support portion 90 operating body 91 foreign matter 120c metal member 120d conductive Layers 122, 122a, 241, 341 Enlarged parts 302a, 302b, 302c, 302d, 302e Switch part 313 Extension parts 332, 342 Wiring 370 Adhesive layer 380 Electrode protective layer 381 Opening 385 Adhesive layer for attachment 390 Terminal part for connector connection

Claims (9)

an insulating substrate;
a movable electrode disposed on the upper surface side of the insulating base and having a displacement portion capable of displacing a position of the insulating base with respect to the upper surface;
a first electrode and a second electrode arranged at positions facing the movable electrode on the upper surface side of the insulating base;
a control circuit connected to each of the first electrode and the second electrode;
The first electrode is arranged at a position facing the displacement portion,
the second electrode is spaced apart from the first electrode;
The control circuit is
By applying a first potential to the first electrode and applying a second potential different from the first potential to the second electrode, the capacitance between at least the first electrode and the movable electrode detecting a change in the capacitance value of the first electrode and the movable electrode, and further detecting a state from proximity to contact between the first electrode and the movable electrode, and making an on/off determination based on these detection results.
switch device. The control circuit connects the second potential to a ground potential when charging the first electrode.
The switch device according to claim 1. The control circuit connects the first potential to a ground potential when discharging from the first electrode.
The switch device according to claim 1 or 2. the movable electrode has a first enlarged portion extending along the upper surface of the insulating base;
The second electrode is arranged at a position facing the first enlarged portion,
The switch device according to any one of claims 1 to 3. the movable electrode generates a click feeling with respect to the operating body when the operating body pushes the displacement portion downward;
The control circuit makes the determination when the click feeling occurs.
The switch device according to any one of claims 1 to 4. The second electrode has a second enlarged portion extending outside the movable electrode in plan view,
The area of the second enlarged portion is equal to or larger than the overlapping area of the second electrode and the movable electrode in a plan view, and
The control circuit detects a change in the capacitance value of the capacitance between the second electrode and the operating body, and detects the approach of the operating body based on the detection result.
The switch device according to any one of claims 1 to 5. The control circuit detects the approach of the operating object in a state in which the first potential and the second potential are set to mutually equal potentials.
The switch device according to claim 6. The control circuit has a detection mode for detecting the approach of the operating object and a determination mode for performing the determination,
switching from the detection mode to the determination mode when the approach of the operating body is detected in the detection mode;
The switch device according to claim 6 or 7. the scan speed in the detection mode is lower than the scan speed in the determination mode;
The switch device according to claim 8.

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