JP4392641B2 - Force detection device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a force detection device.
[0002]
[Prior art]
An example of the force detection device is shown in FIG.
[0003]
In this force detection device, as shown in FIG. 10, when the button part 90 is pushed vertically with respect to the substrate 94, the lower end of the shaft part 91 integrated with the button part 90 turns on the thin switch 93 ( When the button 90 is tilted and pushed, the displacement electrode 92 made of conductive rubber is displaced, and the distance between the displacement electrode 92 and the electrodes Dx +, Dx−, Dy +, Dy− on the substrate 94 changes. In addition, the output voltages of the X axis and Y axis change (joystick function).
[0004]
However, if a thin switch is arranged in the center, the force detection electrodes for the X and Y axes must be arranged outside the thin switch 93, and the displacement electrode 92 made of conductive rubber is arranged further outside. This increases the area of the electrode pattern on the substrate 94, which is disadvantageous for mounting.
[0005]
In the above, a thin switch is arranged in the center, but there is also a demand for minimizing the area of the electrode pattern on the substrate 94 even in the case where the thin switch is not arranged in the center.
[0006]
Therefore, in the industry that manufactures, sells and uses force detectors, (1) we are looking forward to developing a force detector that can reduce the area of the electrode pattern on the substrate. We are looking forward to developing a force detection device that can reduce the area of the electrode pattern on the substrate.
[0007]
[Problems to be solved by the invention]
Therefore, the present invention has an object to provide a force detection device capable of reducing the area of the electrode pattern on the substrate, and to reduce the area of the electrode pattern on the substrate while having a switching function. It is an object of the present invention to provide a force detection device capable of performing the above.
[0008]
[Means for Solving the Problems]
(Invention of Claim 1)
In this force detection device, four electrodes are arranged on the substrate at 90 ° intervals on the X and Y axes, conductive lands are arranged outside the electrodes, and operation buttons are positioned at positions facing the electrodes and the conductive lands. In addition, a displacement electrode having elasticity is provided on the side of the operation button facing the electrode and the conductive land, and the electrode, the conductive land and the displacement electrode are not in contact with each other so that no pressing force is applied to the operation button. First, when the operation button is pressed and a force is applied, the displacement electrode comes into contact with the conductive land, and a capacitance corresponding to the magnitude and direction of the force is generated between the displacement electrode and each electrode.
(Invention of Claim 2)
In the force detection device according to the first aspect of the present invention, each capacitance generated between the displacement electrode and the four electrodes is calculated using an appropriate method, and the force in the X-axis and Y-axis directions is calculated. A signal indicating the size and direction can be output.
(Invention of Claim 3)
In this force detection device, the thin switch is closed when a thin switch is arranged on the upper part of the substrate surrounded by four electrodes and a force perpendicular to the substrate is applied to the operation button. It is supposed to be.
(Invention of Claim 4)
In this force detection device, two electrodes are arranged on the X-axis or Y-axis on the substrate, conductive lands are arranged outside the electrodes, and operation buttons are provided at positions facing the electrodes and the conductive lands. When a displacement electrode having elasticity is provided on the side of the operation button facing the electrode and the conductive land, and the operation button is pushed and a force is applied, the displacement electrode comes into contact with the conductive land and a force is generated between the displacement electrode and each electrode. Capacitance corresponding to the size and direction is generated.
(Invention of Claim 5)
In the force detection device according to the fourth aspect of the present invention, each capacitance generated between the displacement electrode and the two electrodes is calculated using an appropriate method, and the force in the X-axis or Y-axis direction is calculated. A signal indicating the size and direction can be output.
(Invention of Claim 6)
In this force detection device, the thin switch is closed when a thin switch is disposed on a substrate sandwiched between two electrodes and a force perpendicular to the substrate is applied to the operation button. It is like that.
(Invention of Claim 7)
This force detection device relates to the invention according to any one of claims 1 to 6, and the displacement electrode is made of conductive rubber or conductive elastomer.
(Invention of Claim 8)
This force detection device relates to the invention according to any one of claims 1 to 6, wherein the displacement electrode is formed by applying a conductive ink or a conductive paint to a nonconductive rubber or a nonconductive elastomer. .
[0009]
The function of the force detection device of the above invention will be clarified in the following embodiments of the invention.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described with reference to the drawings shown as examples.
[Embodiment 1]
FIG. 1 shows a cross-sectional view of a force detection device S according to Embodiment 1 of the present invention. FIG. 2 shows a conductive land DG and electrodes Dx +, Dx−, Dy +, Dy on a substrate 1 constituting the force detection device S. -The top view of the thin switch 5 is shown.
(Regarding the configuration of the force detection device S)
As shown in FIG. 1, the force detection device S includes a substrate 1, an operation button 2 disposed opposite to the substrate 1, a displacement electrode 3 disposed on a lower surface of the operation button 2, and the operation button. And a fixture 4 for fixing 2 on the substrate 1.
[0011]
As shown in FIG. 1, the substrate 1 is composed of a thin printed circuit board, and as shown in FIG. 2, circular electrodes Dx +, Dx−, Dy +, Dy− divided into four on the upper surface are XY axes. An annular conductive land DG surrounding the electrodes Dx +, Dx−, Dy +, and Dy− with the origin O as the center is disposed on the upper side and at an equal distance from the origin O. Here, in this embodiment, the thin switch 5 is arranged as shown in FIGS. 1 and 2 on the substrate 1 surrounded by the electrodes Dx +, Dx−, Dy +, Dy−. The electrodes Dx +, Dx−, Dy +, Dy− and the conductive lands DG are formed by printing a copper layer formed on the substrate 1 with a solder layer, gold plating or silver plating, or carbon printing. It is formed by welding a solder, and is covered with an insulating film R.
[0012]
As shown in FIGS. 1 and 3, the operation button 2 includes a hard part 20 made of polycarbonate and a soft part 21 made of non-conductive rubber or non-conductive elastomer, and both are bonded.
[0013]
As shown in FIG. 1, the hard part 20 is composed of a push-in part 20a having an inverted dish shape and a hanging bar 20b projecting from the central lower surface of the push-in part 20a. The lower end of 20b is formed in a hemispherical shape.
[0014]
The soft portion 21 mainly supports the operation button 2 on the substrate 1, and as shown in FIG. 1, a fixed portion 21 a that is inserted into the push-in portion 20 a and a fixture 4 that is attached to the substrate 1. It comprises a portion 22 and a thin portion 23 connecting the portion 21a and the fixed portion 22.
[0015]
The displacement electrode 3 is provided on the surface of the soft portion 21 facing the electrodes Dx +, Dx−, Dy +, Dy− and the conductive land DG as shown in FIG. 1, and is formed of an annular thin plate as shown in FIG. It is made of conductive rubber or conductive elastomer. It should be noted that the distance between the displacement electrode 3 and the conductive land DG is not contacted even when the operation button 2 is pushed into the substrate 1 by a minute distance and the hanging bar 20b turns on the thin switch 5. The dimensions are set to be
[0016]
As shown in FIG. 1, the fixture 4 has an annular shape in plan view with an L-shaped cross section, and the operation button 2 is attached in such a manner that the fixing portion 22 is pressed against the substrate 1.
[0017]
The thin switch 5 has a thickness of several millimeters. Specifically, the thin switch 5 is a tactile switch having a metal dome portion 50 with a small push amount.
[0018]
Here, in the state where the displacement electrode 3 and the conductive land DG are in contact with each other as shown in FIG. 5, the capacitances Cx +, Cx−, and Cx +, Dx +, Dy− between the displacement electrode 3 and the electrodes Dx +, Dx−, Dy +, Dy−. Cy +, Cy− are formed, and when the operation button 2 is not pushed in, the lower end of the hanging bar 20b is in contact with the thin switch 5 (or is not in contact with a small gap); It is supposed to be. A voltage having a constant period or a constant voltage is applied to the electrodes Dx +, Dx−, Dy +, Dy−, and the conductive land DG is connected to 0 V of the power source.
[0019]
In this embodiment, as shown in FIG. 6, the operation buttons 2 are calculated by calculating [(Cx +) − (Cx−)] and [(Cy +) − (Cy−)] using an appropriate method. X-axis direction and Y-axis direction signals corresponding to the magnitude and direction of the force for pushing in are obtained.
(About the function of this force detection device S)
(1) When the operation button 2 is pushed in the Z-axis direction (perpendicular to the substrate 1), the thin-walled portion 23 is deformed, and the hanging rod 20b moves the metal dome portion 50 of the thin switch 5 as shown in FIG. Press to turn on the switch. At this time, since the distance between the displacement electrode 3 and the conductive land DG is set as described above, the displacement electrode 3 and the conductive land DG are not connected as shown in FIG. No electrostatic capacitance Cx +, Cx−, Cy +, Cy− is generated between the electrode 3 and the electrodes Dx +, Dx−, Dy +, Dy−.
(2) Next, as shown in FIG. 5, when the operation button 2 is tilted and pushed in, the distance between the displacement electrode 3 and the electrode Dx + decreases, and the displacement electrode 3 and the conductive land DG come into contact with each other. It becomes the GND potential. On the other hand, since voltages are applied to the electrodes Dx +, Dx−, Dy +, and Dy−, when the displacement electrode 3 reaches the GND potential, between the displacement electrode 3 and the electrodes Dx +, Dx−, Dy +, and Dy−. Capacitances Cx +, Cx−, Cy +, and Cy− are generated. At this time, the electrostatic capacity is inversely proportional to the distance between the displacement electrode 3 and the electrodes Dx +, Dx−, Dy +, Dy−, so that the electrostatic capacity Cx + becomes the largest value, and (Cx −) <[(Cy +) = ( Cy −)] <(Cx +) (1). Here, since the displacement electrode 3 and the soft part 21 are comprised with the elastic body, if the operation button 2 is pressed hard, it will deform | transform according to the magnitude | size of force. For this reason, the capacitances Cx +, Cx−, Cy +, and Cy− increase in accordance with the distance between the electrodes while maintaining the relationship of the expression (1). The same can be said for the forces in other directions.
[0020]
Therefore, signals in the X-axis direction and the Y-axis direction corresponding to the magnitude and the direction of the force for pressing the operation button 2 are obtained.
{Circle around (3)} When applying the force for tilting the operation button 2 described in {circle around (2)}, it is possible to apply the force with a person's finger while being conscious not to turn on the thin switch 5.
[0021]
From the above, it is possible to intentionally turn on the thin switch 5 or change the output signals of the X-axis and the Y-axis by adjusting the direction and strength of the pressing force of the operation button 2. I understand that.
[0022]
Also, in the force detection device S of the present invention, the area of the conductive land DG can be reduced, so that it is clear that it is very advantageous in terms of mounting on equipment.
(4) Conversely, when the force applied to the operation button 2 is removed, the displacement electrode 3 moves away from the conductive land DG on the substrate 1, and at that time, the displacement electrode 3 and the electrodes Dx +, Dx-, Dy +, Dy- Capacitances Cx +, Cx−, Cy +, and Cy− are not generated between them. This phenomenon is caused by the force applied to the operation button 2 even if the displacement electrode 3 and the rubber constituting the soft portion 21 are slightly distorted and do not return to the original position. The capacitances Cx +, Cx−, Cy +, and Cy− are “0” (can be neglected because the stray capacitance is small) regardless of the minute distortion of the displacement electrode 3 and the soft portion 21 because they occur reliably if they are separated. . That is, the X-axis and Y-axis outputs shown in FIG. 6 are reliably restored to the original, and almost no hysteresis occurs.
[0023]
Therefore, when the present invention is applied as a joystick, it is possible to provide a joystick with good reproducibility that hardly generates hysteresis in the output.
[Embodiment 2]
FIG. 7 shows a cross-sectional view of a force detection device S according to Embodiment 2 of the present invention. FIG. 8 shows a conductive land DG, electrodes Dx +, Dx−, and a thin switch 5 on a substrate 1 constituting the force detection device S. Further, a plan view of the displacement electrode 3 provided on the operation button 2 side is shown.
[0024]
As shown in FIG. 7, the force detection device S includes a substrate 1, an operation button 2, a displacement electrode 3, a fixture 4, and a thin switch 5, as shown in FIG. In order to detect the magnitude of the force (or the Y axis) and the direction of the force, the second embodiment differs from the first embodiment in the following points.
[0025]
As shown in FIGS. 7 and 8, the substrate 1 has a conductive land DG, an electrode Dx +, a thin switch 5, an electrode Dx−, and a conductive land DG arranged on a straight line L in this order.
[0026]
As shown in FIG. 7, the operation button 2 is of a seesaw button type that can be tilted and pushed in a uniaxial direction.
[0027]
The displacement electrode 3, the fixture 4, the thin switch 5, and the circuit for capacitance-voltage conversion are the same as those in the first embodiment.
[0028]
Since the force detection device S is configured as described above, as shown in FIG. 9, when one end of the seesaw button type operation button 2 is pushed in, the static force is detected between the displacement electrode 3 and the electrodes Dx + and Dx−. Capacitances Cx + and Cx− are generated and a signal in the uniaxial direction is output. When the central portion of the operation button 2 is pushed in, the hanging bar 20b pushes the metal dome portion 50 of the thin switch 5 into the switch. Is turned on. Since these functions have been described in Embodiment 1, they are omitted here.
(Other embodiments)
In the said embodiment, although the displacement electrode 3 is made into the common electrode, it is not limited to this. That is, in the second embodiment, a Dx + displacement electrode and a Dx− displacement electrode separated from each other may be provided.
[0029]
Moreover, in the said embodiment, although the tactile switch is employ | adopted as a thin switch, all can be employ | adopted if it has an equivalent function.
[0030]
【The invention's effect】
Since the present invention is configured as described above, it has the following effects.
[0031]
As is apparent from the description in the column of the embodiment of the invention, it is possible to provide a force detection device capable of reducing the area of the electrode pattern on the substrate, and further, while maintaining the switching function, A force detection device capable of reducing the area could be provided.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a force detection device according to a first embodiment of the present invention.
FIG. 2 is a plan view of conductive lands, electrodes, and thin switches arranged on a substrate constituting the force detection device.
FIG. 3 is a view of an operation button and a displacement electrode constituting the force detection device as viewed from below.
FIG. 4 is a cross-sectional view when the operation button is pushed vertically to the substrate.
FIG. 5 is a cross-sectional view when the operation button is pushed obliquely with respect to the substrate.
FIG. 6 is a diagram of an application circuit that can be employed in this embodiment.
FIG. 7 is a cross-sectional view of a force detection device according to a second embodiment of the present invention.
FIG. 8 is a plan view of conductive lands, electrodes, and thin switches arranged on a substrate constituting the force detection device.
FIG. 9 is a cross-sectional view when the operation button is pushed obliquely with respect to the substrate.
FIG. 10 is a cross-sectional view of a prior art force detection device.
FIG. 11 is a plan view of conductive lands, electrodes, and thin switches arranged on a substrate constituting a force detection device of the prior art.
[Explanation of symbols]
S force detection device Dx + electrode Dx− electrode Dy + electrode Dy− electrode DG conductive land 1 substrate 2 operation button 3 displacement electrode 4 fixture 5 thin switch

Claims (8)

Four electrodes are arranged on the substrate at 90 ° intervals on the X and Y axes, conductive lands are disposed outside the electrodes, operation buttons are provided at positions facing the electrodes and the conductive lands, and the operation buttons are provided. In the case where a displacement electrode having elasticity is provided on the opposite side of the electrode and the conductive land, and the pressing force is not applied to the operation button, the electrode, the conductive land and the displacement electrode are not in contact, and the operation button is pressed When a force is applied, the displacement electrode comes into contact with the conductive land, and a capacitance according to the magnitude and direction of the force is generated between the displacement electrode and each electrode. apparatus. Each capacitance generated between the displacement electrode and the four electrodes is calculated by using an appropriate method so that a signal indicating the magnitude and direction of the force in the X-axis and Y-axis directions can be output. The force detection device according to claim 1. 2. The thin switch is closed when a thin switch is arranged on an upper part of the substrate surrounded by four electrodes and a force perpendicular to the substrate is applied to the operation button. Force detection device. Two electrodes are disposed on the X-axis or Y-axis on the substrate, a conductive land is disposed outside the electrode, an operation button is provided at a position facing the electrode and the conductive land, and the electrode in the operation button is When an elastic displacement electrode is provided on the side facing the conductive land, and the operation button is pushed in and a force is applied, the displacement electrode comes in contact with the conductive land, depending on the magnitude and direction of the force between the displacement electrode and each electrode. A force detection device characterized in that a capacitance is generated. Each capacitance generated between the displacement electrode and the two electrodes is calculated using an appropriate method so that a signal indicating the magnitude and direction of the force in the X-axis or Y-axis direction can be output. The force detection device according to claim 4. 5. The force according to claim 4, wherein a thin switch is disposed on a substrate sandwiched between two electrodes, and the thin switch is closed when a force perpendicular to the substrate is applied to the operation button. Detection device. The force detection device according to any one of claims 1 to 6, wherein the displacement electrode is made of conductive rubber or conductive elastomer. The force detection device according to claim 1, wherein the displacement electrode is formed by applying conductive ink or conductive paint to a nonconductive rubber or a nonconductive elastomer.

Images