JP2003287468A - Capacitance type sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent output from being affected by components in other axial directions. <P>SOLUTION: A diaphragm 40 is arranged at a location opposite to electrodes E1-E5 for capacitative elements formed on a substrate 20. The diaphragm 40 is displaced in the direction of a Z axis as a stick 30 is operated from the outside and moved in the direction of the Z axis and constitutes the capacitative elements C0-C5 in-between the electrodes E1-E5 for the capacitative elements. Recessed parts 41-45 are formed and arranged in the upper surface of the diaphragm 40 in the same circumference containing a region inside and corresponding to the stick 30. In the case that a force in the direction of a Y axis is exerted on the stick 30 from the outside, an output component in the direction of an X axis and an output component in the direction of the Z axis change approximately linearly to the magnitude of the force in the direction of the Y axis. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a capacitance type sensor suitable for use in detecting forces in multidimensional directions.

[0002]

2. Description of the Related Art A capacitance type sensor is used as a device for converting the magnitude and direction of a force applied by an operator into an electric signal. For example, as an input device for game machines,
A device incorporated as a capacitance type force sensor (so-called joystick) for inputting operation in multidimensional directions is used. With the capacitance type sensor, an operation amount having a predetermined dynamic range can be input as the magnitude of the force transmitted from the operator. It is also used as a two-dimensional or three-dimensional force sensor that can detect the applied force separately for each direction component. In particular, a capacitance element is formed by two electrodes,
Capacitance type force sensors that detect force based on changes in capacitance value due to changes in electrode spacing have various advantages because they have the advantage of simplifying the structure and reducing costs. It has been put to practical use in the field.

As shown in FIG. 17, a capacitance type sensor is formed on a substrate 520, a stick 530 which is an operating member to which force is applied from the outside, a metal diaphragm 540, and a substrate 520. Electrode E for capacitive element
501 to E505 and the reference electrode E500, a resist film 550 formed so as to be in close contact with the capacitive element electrodes E501 to E505 and cover the substrate 520, and a metal film disposed between the diaphragm 540 and the reference electrode E500. Some of them have a spacer 560 and a cover plate 570 arranged so as to surround the periphery of the stick 530.

On the substrate 520, as shown in FIG.
A circular capacitive element electrode E505 centered on the origin O,
Electrodes E501 to E50 for capacitance elements arranged outside thereof
4 and a reference electrode E500 arranged further outside thereof. Here, the pair of capacitive element electrodes E5
01 and E502 are arranged in line symmetry with respect to the Y axis with being separated from each other in the X axis direction, and a pair of electrodes for capacitive element E5 is provided.
03 and E504 are arranged in line symmetry with respect to the X axis with being separated in the Y axis direction.

Through holes (not shown) are formed in the cover plate 570, the diaphragm 540, the spacer 560 and the substrate 520 at corresponding positions. Therefore, the screws 571 are attached to the cover plate 570,
The diaphragm 540, the spacer 560, and the substrate 520 are fitted into the through holes in this order, and then screwed into the nut 572, so that they are fixed to each other.

Here, for example, when a force in the positive direction of the X-axis is applied to the stick 530 from the outside, the portion of the diaphragm 540 facing the capacitive element electrode E501 is displaced downward, and the capacitive element electrode E502 is moved. The facing portions are deformed so as to be displaced upward. When the distance between the diaphragm 540 and each of the capacitive element electrodes E501 and E502 changes, the capacitance value of the capacitive element formed between each changes. Therefore,
By detecting this change in capacitance value, it is possible to know the magnitude and direction of the force in the positive direction of the X-axis applied from the outside. At this time, the X-axis component of the output of the sensor often changes almost linearly (in proportion) to the magnitude of the force applied to the stick 530 in the positive X-axis direction.

[0007]

The stick 53 is also used.
When a force in the X-axis positive direction is applied to 0, no force is applied in the Y-axis direction and the Z-axis direction, which are directions orthogonal to the X-axis direction (another axis direction). However, since the diaphragm 540 is a simple plate-shaped member, X
When a force in the positive axial direction is applied, the diaphragm 540 is likely to bend due to twisting in a relatively wide range,
The portion of the diaphragm 540 corresponding to the Y-axis direction and the Z-axis direction may also be deformed. Therefore,
Diaphragm 540 and capacitance element electrodes E503, E50
4 and the distance between each of E505 and
Since the capacitance value of the capacitive element formed between them changes, it is also output in the Y-axis direction and the Z-axis direction where no force is applied. This makes it impossible to properly detect the force applied to the stick 530 in the positive direction of the X axis.

Further, the diaphragm 540 depends on the degree of close contact between the diaphragm 540 and the cover plate 570 and the spacer 560 (fixed state of the diaphragm 540).
The amount of deflection at the portion corresponding to the Y-axis direction and the Z-axis direction,
That is, the Y-axis direction component and the Z-axis direction component of the output are X
It may not change linearly with the magnitude of the force in the positive axial direction. Here, when the Y-axis direction component and the Z-axis direction component of the output linearly change with respect to the magnitude of the force in the X-axis positive direction, the output of each direction component is used for calculation, The force in the X-axis positive direction can be detected properly, but if not, the force in the X-axis positive direction cannot be detected properly. Therefore, the individual difference of the sensors that occurs when a plurality of sensors of the same type are manufactured cannot be properly compensated by calculation.

Therefore, a main object of the present invention is to provide a capacitance type sensor which is less likely to be affected by the other axial component of the output.

[0010]

As a result of continuing the research for achieving the above-mentioned object, the present inventor found that by appropriately forming a concave portion in a diaphragm constituting a capacitive element between the capacitive element electrode and the capacitive element electrode. , When a force is applied in the specified axis direction, the direction of the output orthogonal to the specified axis direction (other axis direction)
It has been found that the component of becomes linearly changed with respect to the magnitude of the force in the predetermined axial direction.

That is, the capacitance type sensor according to claim 1 is located between the substrate, the detection member facing the substrate, and the substrate and the detection member, and the detection member is the substrate. A conductive member which is capable of being displaced in the same direction as it is displaced in the vertical direction, and in which a concave portion is formed on the circumference such that the region corresponding to the detection member is included inside; An electrode for a capacitive element that is formed on the conductive member and forms a capacitive element with the conductive member, and is formed on the substrate and electrically connected to the conductive member, and is grounded or at a constant potential. A held reference electrode, and using a signal input to the capacitance element electrode, the static capacitance of the capacitance element caused by a change in the distance between the conductive member and the capacitance element electrode. Based on the change in capacitance being detected It is characterized in that it is recognizable to displacement of the sensing member are.

According to the first aspect of the present invention, the conductive member has the concave portion arranged on the circumference so as to include the region corresponding to the detecting member on the inner side. Is applied, the other axial component of the output changes substantially linearly with the magnitude of the force in the predetermined axial direction. The other axial component of the output linearly changes with good reproducibility with respect to the magnitude of the force in the predetermined axial direction.
Therefore, the directional component of the acting force is properly detected by performing the calculation using the output of each directional component. As a result, the influence of the fixed state of the conductive member is less likely to occur, and the individual difference of the sensor can be appropriately compensated by calculation.

The above-mentioned effects are obtained
It can be inferred that it is due to the following reasons. When a force is applied to the detection member in the predetermined axial direction from the outside,
The conductive member is easily deformed by the concave portion having low rigidity, and is deformed around the concave portion formed in the portion corresponding to the predetermined axial direction and the other axial direction of the conductive member. At this time, since the bending of the conductive member in the other axial direction is concentrated in the concave portion corresponding to that direction, the bending amount is likely to be relatively large. Therefore,
In the conductive member in which the recess is formed, the deformed state in the other axial direction of the conductive member is the fixed state of the conductive member as compared with the case of the flat plate-shaped conductive member in which the recess is not formed. Change less due to the effect of. Therefore, the amount of bending in the recess corresponding to the other axial direction of the conductive member changes substantially linearly with the magnitude of the force in the predetermined axial direction. At this time, the other axial component of the output also changes substantially linearly with respect to the magnitude of the force in the predetermined axial direction.

Further, since the conductive member has a concave portion formed on the circumference thereof, it can be applied to a force in any direction regardless of the direction of the force applied to the detecting member from the outside. The conductive member can be deformed without directivity. Therefore, the situation in which the sensitivity of the sensor varies depending on the direction of the force applied to the detection member due to the directionality of the deformation of the conductive member rarely occurs. as a result,
It is possible to obtain a sensor having no directivity.

Further, the capacitance type sensor according to claim 2 is characterized in that the conductive member has a plurality of recesses arranged so as to be separated from each other along the circumference. Is.

According to the second aspect of the present invention, the conductive member is provided with recesses which are thin and thin portions and recesses which are not thick and which are thick and are alternately arranged along the circumferential direction. I'm out. Therefore, when a force is applied to the detection member, the above two parts have a twisted structure. Therefore, when the force is no longer applied to the detection member from the state in which the force is applied, the conductive member is formed by the restoring force of the twisted structure when the recess is not formed and when the recess is formed in an annular shape. It is easier to return to the original state (state without twisting) as compared with the case of being twisted.
Thereby, the reaction with respect to the detection member can be made quick.

Further, the electrostatic capacitance type sensor according to a third aspect of the invention is characterized in that the conductive member has a plurality of concave portions arranged concentrically so as to be separated from each other.

According to the third aspect of the present invention, the stress generated in the vicinity of each end of each of the plurality of concentric annular recesses is in the vicinity of both ends of one annular recess arranged on the same circumference. Compared with the stress that occurs, it becomes smaller by being dispersed. Therefore, the stress generated near one end of the recess is reduced, and the durability of the conductive member is improved.

Further, the electrostatic capacitance type sensor according to a fourth aspect is characterized in that the concave portion is formed on a surface of the conductive member opposite to a surface facing the substrate.

According to the present invention, since the recess is formed on the surface of the conductive member opposite to the surface facing the substrate, the recess faces the capacitor element electrode on the surface facing the substrate of the conductive member. Compared with the case where it is formed to
The space between the conductive member and the capacitance element electrode is reduced. Therefore, the capacitance value of the capacitive element formed between the conductive member and the capacitive element electrode becomes relatively large,
The sensitivity of the sensor can be improved.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic sectional view of a capacitance type sensor according to an embodiment of the present invention. FIG. 2 is a diagram showing an arrangement of a plurality of electrodes formed on the substrate of the capacitance type sensor of FIG. Figure 3
FIG. 2 is a top view of a diaphragm of the capacitance type sensor of FIG. 1. The embodiment described below uses the capacitance sensor of the present invention as a force sensor.

The capacitance type sensor 1 is formed on the substrate 20, the stick 30 which is an operating member to which a force is applied from the outside by being operated by a person, a metal diaphragm 40, and the substrate 20. The capacitive element electrodes E1 to E5 (only E11, E2, and E5 are shown in FIG. 1) and the reference electrode (common electrode) E0 are closely attached to the capacitive element electrodes E1 to E5 to cover the substrate 20. It has the formed resist film 50, a metal spacer 60 arranged between the diaphragm 40 and the reference electrode E0, and a cover plate 70 arranged so as to surround the stick 30.

Here, for convenience of explanation, as shown in FIG.
The XYZ three-dimensional coordinate system is defined, and the arrangement of each component will be described with reference to this coordinate system. That is, in FIG. 1, the origin O is defined at a position facing the center position of the diaphragm 40 on the substrate 20, and the X axis is defined in the right horizontal direction.
The Z axis is defined in the upper vertical direction, and the Y axis is defined in the vertical direction in the plane of the drawing. Here, the surface of the substrate 20 is XY
A plane is defined, and the center position of the capacitive element electrode E5 on the substrate 20, the center position of the diaphragm 40, and the stick 3 are defined.
The Z axis passes through the axial center position of 0.

The board 20 is a printed circuit board for a general electronic circuit, and a glass epoxy board is used in this example. A film-shaped substrate such as a polyimide film may be used as the substrate 20, but in the case of a film-shaped substrate, since it has flexibility, it is arranged on a supporting substrate having sufficient rigidity. It is preferable to use.
The substrate 20 is formed with a through hole (not shown) into which a screw (screw) 71 for fixing the cover plate 70, the diaphragm 40, and the spacer 60 is inserted.

On the substrate 20, as shown in FIG. 2, a circular capacitive element electrode E5 centered on the origin O,
Substantially fan-shaped capacitive element electrodes E1 to E arranged on the outside thereof
4 and an annular (ring-shaped) reference electrode E0 centered on the origin O, which is arranged outside thereof.
Here, the pair of capacitance element electrodes E1 and E2 are arranged in line symmetry with respect to the Y axis while being separated in the X axis direction.
The pair of capacitive element electrodes E3 and E4 are arranged in line symmetry with respect to the X axis while being separated in the Y axis direction. The reference electrode E0 may be formed between the capacitive element electrode E5 and the capacitive element electrodes E1 to E4. Alternatively, the capacitive element electrode E5 may be eliminated and a circular reference electrode E0 centered on the origin O may be formed. However, in this case,
The Z-axis direction component cannot be detected.

Here, the capacitor element electrode E1 is arranged so as to correspond to the positive direction of the X axis, and the capacitor element electrode E2 is X.
It is arranged so as to correspond to the axial negative direction, and is used for detecting the X-axis direction component of the force from the outside. The capacitive element electrode E3 is arranged so as to correspond to the Y-axis positive direction, and the capacitive element electrode E4 is arranged so as to correspond to the Y-axis negative direction. Used for detection. Further, the capacitive element electrode E5 is arranged on the origin O and is used for detecting the Z-axis direction component of the external force.

The capacitive element electrodes E1 to E5 and the reference electrode E0 are connected to terminals T0 to T0 by using through holes or the like.
T5 (see FIG. 4) respectively, and the terminal T0
Through T5, it is connected to an external electronic circuit or the like. Note that, here, the reference electrode E0 is connected to the terminal T
It is grounded through 0.

The resist film 50 is a film member having an insulating property and is formed so as to be in close contact with the capacitive element electrodes E1 to E5 on the substrate 20 and cover the substrate 20. Therefore, the resist film 50 has a function of preventing the capacitive element electrodes E1 to E5 made of copper or the like from being exposed to air and preventing them from being oxidized. Further, since the resist film 50 is formed, the capacitive element electrodes E1 to E5 do not come into direct contact with the diaphragm 40.

The stick 30 is composed of a small-diameter upper step portion 31 serving as a force receiving portion and a large-diameter lower step portion 32 extending to the lower end portion of the upper step portion 31. Since the thickness (height) of the upper step portion 31 is larger than the thickness of the lower step portion 32, the stick 30 is a rod-shaped member that extends in the Z-axis direction as a whole. Here, the outer diameter of the lower portion 32 is
The diameter is slightly larger than the diameter of the circle formed by connecting the inner curves of the capacitive element electrodes E1 to E4.
The outer diameter of 1 is substantially the same as the outer diameter of the capacitive element electrode E5. Therefore, the X-axis positive direction part, the X-axis negative direction part, the Y-axis positive direction part and the Y-axis part of the lower part 32 of the stick 30 are
The negative portion in the axial direction is arranged so as to correspond to each of the capacitive element electrodes E1 to E4, that is, so as to correspond to the operation direction (the moving direction of the cursor).

The diaphragm 40 is a rectangular thin steel plate having a length substantially equal to the outer diameter of the reference electrode E0. Since the diaphragm 40 is made of metal, it has conductivity. The upper surface of the diaphragm 40 is shown in FIG.
As shown in FIG. 4, a plurality of substantially fan-shaped recesses (recesses) 41 to 45 arranged on the same circumference with the center position as the center are formed, and four recesses (dents) arranged near four corners are formed. A circular through hole 48 is formed.

The diaphragm 40 is made of a steel plate,
For example, any material may be used as long as it is a conductive member such as conductive plastic, conductive rubber, or silicon.

The recesses 41 to 45 are located on the upper surface of the diaphragm 40 (the surface opposite to the surface facing the substrate 20) with the central position of the diaphragm 40 as the center and the stick 30.
The outer curves of the capacitance element electrodes E1 to E4 are connected to each other outside a region surrounded by a circle having a diameter substantially the same as the outer diameter of the lower step portion 32 and centered on the center position of the diaphragm 40. It is formed inside the area enclosed by the circle. Therefore, the recesses 41 to 45 are provided on the upper surface of the diaphragm 40 so as to correspond to the capacitive element electrodes E1 to E4 on the substrate 20 on the same circumference including the region corresponding to the stick 30 inside. ing.

Here, the concave portion 41 is formed at a position corresponding to the positive direction of the X axis, and the concave portion 42 is formed at a position corresponding to the negative direction of the X axis. Further, similarly to this, the concave portion 4
Reference numerals 3 and 44 are formed at positions corresponding to the Y-axis positive direction and the Y-axis negative direction, respectively. The recess 45 is formed between the recess 41 and the recess 43, between the recess 43 and the recess 42,
Between the recesses 42 and the recesses 44, and between the recesses 44 and the recesses 41, they are formed so as to be spaced apart from each other by the same distance (uniformly). In the present embodiment, the recess 4 is formed between the recesses 41 to 44.
5 are formed three by three, and the diaphragm 40 is
A total of 16 recesses are formed along the same circumferential direction.

The recesses 41 to 45 are formed to have the same size and depth. here,
Regarding the size of the recesses 41 to 45, the length of the recesses 41 to 45 in the direction along the circumference and the length in the direction perpendicular to the circumference are both the diaphragm 40.
Is greater than the thickness of. Also, the recesses 41 to 45
As for the depth of each, the length is half the thickness of the diaphragm 40. The size and depth of the recess can be arbitrarily changed. However, the depth of the recess is preferably one-third or more of the thickness of the diaphragm and half or less of the thickness of the diaphragm.

The recesses 41 to 45 are formed by the diaphragm 4
A predetermined portion of 0 is formed by scraping off by an etching method. Here, the etching process is
Since it is not necessary to use an expensive mold as in the press process, and the process can be performed only with an inexpensive plate, the cost of the diaphragm 40 can be reduced. further,
By forming the recesses 41 to 45 by etching, the diaphragm 40 can be made thinner. Therefore, it is possible to reduce the cost of the capacitance type sensor 1 and to reduce the thickness of the capacitance type sensor 1. Further, the outer shape of the diaphragm 40 and the processing of the through hole 48 can also be performed by an etching method.

Further, the diaphragm 40 in which the recesses 41 to 45 are formed is not limited to the one in which the recess is formed in one simple flat plate-shaped diaphragm, and a simple flat plate-shaped (no recessed part) diaphragm is used. , Recesses 41-45
The two diaphragms, including the other diaphragm having the opening corresponding to the above, may be pressure-welded or bonded by heat.

The four through holes 48 are used to fix the diaphragm 40, which is arranged so as to face the capacitive element electrodes E1 to E5, to the substrate 20. Therefore, the screw 71 for fixing to the substrate 20 is fitted into the through hole 48.

The lower surface of the lower step portion 32 of the stick 30 is fixed to the upper surface of the diaphragm 40 by welding, that is, the stick 30 and the diaphragm 40 are integrated. Therefore, the force applied to the stick 30 from the outside is efficiently transmitted to the diaphragm 40.

The spacer 60 is a metal member,
It has a predetermined thickness. The spacer 60 is arranged between the diaphragm 40 and the reference electrode E0 on the substrate 20, and has a function of electrically connecting the diaphragm 40 and the reference electrode E0. Furthermore, the spacer 6
0 has a function of separating the diaphragm 40 and the capacitance element electrodes E1 to E5 by a predetermined distance. The spacer 60 is formed with a through hole (not shown) into which a screw 71 for fixing to the substrate 20 is inserted.

The cover plate 70 is arranged so as to surround the periphery of the stick 30. Then, the cover plate 70 is formed with a through hole (not shown) into which a screw 71 for fixing to the substrate 20 is inserted, and the cover plate 70 is fixed to the substrate 20 as described later. In this case, the diaphragm 40 can be pressed against the substrate 20 almost uniformly.

Here, the cover plate 70, the diaphragm 40 and the spacer 60 are fixed to the substrate 20, as shown in FIG. That is, after the screws 71 are inserted into the through hole (not shown) of the cover plate 70, the through hole 48 of the diaphragm 40, the through hole of the spacer 60 (not shown), and the through hole of the substrate 20 (not shown) in this order. , Are fixed to each other by being screwed to the nut 72.

Therefore, the diaphragm 40 is pressed toward the substrate 20 by the cover plate 70 by the fastening force of the screw 71 and the nut 72. Then, when no force is applied to the stick 30 from the outside, the distance between the diaphragm 40 and the substrate 20, that is, the distance between the diaphragm 40 and the capacitance element electrodes E1 to E5 is substantially constant. Is kept at.

Next, the operation of the capacitance type sensor 1 according to the present embodiment configured as described above will be described with reference to the drawings. FIG. 4 is an equivalent circuit diagram for the configuration of the capacitance type sensor shown in FIG. FIG. 5 is an explanatory diagram for explaining a method of deriving an output signal from a periodic signal input to the capacitance type sensor shown in FIG. Figure 6
FIG. 3 is a schematic cross-sectional view of a side surface when the detection member of the capacitance type sensor shown in FIG. 1 is operated in the positive direction of the X axis.

First, a circuit configuration equivalent to the configuration of the capacitance type sensor 1 will be described with reference to FIG. Board 20
The capacitive element electrodes E1 to E5 formed above are opposed to the diaphragm 40 while being separated from each other. Therefore, the capacitive element C is provided between the displaceable diaphragm 40, which is a common electrode, and the fixed individual capacitive element electrodes E1 to E5.
1 to C5 are formed. Here, the capacitive elements C1 to C
It can be said that each of the variable capacitance elements 5 is configured so that the capacitance value thereof changes due to the displacement of the diaphragm 40.

The reference electrode E0 is electrically connected to the diaphragm 40 via a metal spacer 60 (see FIG. 1). Therefore, the diaphragm 40 is connected to the grounded terminal T0 via the spacer 60 and the reference electrode E0.

Here, the capacitance value of each of the capacitance elements C1 to C5 is the terminal T0 connected to the diaphragm 40.
And the capacitance values between the terminals T1 to T5 connected to the capacitance element electrodes E1 to E5, respectively, can be independently measured.

Next, referring to FIG. 5, a method of deriving an output signal indicating the magnitude and direction of the external force on the stick 30 from the change in the capacitance value of each of the capacitive elements C1 to C5 will be described. explain. Here, the output signal Vx,
Vy and Vz are components of the external force in the X-axis direction,
The magnitude and direction of the Y-axis direction component and the Z-axis direction component are shown.

The capacitive element C6 shown in FIG. 5 is a fixed capacitive element disposed on the lower surface of the substrate 20 so as to always maintain a constant electrostatic capacitance value, and is, for example, a ceramic capacitor or the capacitance of the input terminal of the IC. Elements or the like can be used. Here, one electrode of the capacitive element C6 is connected to a C / V conversion circuit that derives the output signal Vz, and the other electrode is grounded. This capacitive element C6
Is used together with the capacitive element C5 to derive the output signal Vz of the Z-axis direction component of the external force.

Here, in order to derive the output signals Vx, Vy, Vz, a periodic signal such as a clock signal is always input to the terminals T1 to T6. When the stick 30 is displaced by receiving an external force while the periodic signal is input to the terminals T1 to T6, the diaphragm 40 is displaced in the Z-axis direction accordingly, and the electrode intervals of the capacitive elements C1 to C5 are changed. The capacitance values of the capacitance elements C1 to C5 change accordingly. Then, the phases of the periodic signals input to the terminals T1 to T5 are deviated. In this way, by using the phase shift generated in the periodic signal, an output indicating the displacement of the stick 30, that is, the magnitude and direction of the force received by the stick 30 from the outside in the X-axis direction, the Y-axis direction, and the Z-axis direction. The signals Vx, Vy, Vz can be obtained.

More specifically, the terminals T1 to T6 will be described.
When a periodic signal is input to the terminals T1, T3, T
The periodic signal A is input to 5 while the terminals T2,
To T4 and T6, the periodic signal B having the same period as the periodic signal A and different from the phase of the periodic signal A is input. At that time, the stick 30 receives a force from the outside,
When the capacitance values of the capacitive elements C1 to C5 change, the phases of the periodic signal A or the periodic signal B input to the terminals T1 to T5 respectively deviate by different amounts. Since the capacitance value of the capacitive element C6 does not change, the phase of the periodic signal B input to the terminal T6 does not shift.

That is, when the external force includes a component in the X-axis direction, the capacitance value of the capacitive element C1 changes,
When the phase of the periodic signal A input to the terminal T1 is shifted, the capacitance value of the capacitive element C2 changes, and
The phase of the periodic signal B input to 2 also shifts. Here, changes in the capacitance values of the capacitive elements C1 and C2 correspond to the X-axis positive direction component and the X-axis negative direction component of the external force, respectively. Therefore, the phase shift of the periodic signal A input to the terminal T1 and the phase shift of the periodic signal B input to the terminal T2 are phase shifts in opposite directions. In this way, the output signal Vx is derived by reading the phase shift of the periodic signal A and the periodic signal B input to the terminal T1 and the terminal T2, respectively, by the signal processing circuit using the logic element. The sign of the output signal Vx indicates whether the X-axis direction component of the external force is in the positive direction or the negative direction, and its absolute value indicates the magnitude of the X-axis direction component.

When the external force includes the Y-axis direction component, the capacitance value of the capacitive element C3 changes, the phase of the periodic signal A input to the terminal T3 shifts, and the capacitance changes. The capacitance value of the element C4 changes, and the phase of the periodic signal B input to the terminal T4 also shifts. Here, changes in the capacitance values of the capacitive elements C3 and C4 correspond to the Y-axis positive direction component and the Y-axis negative direction component of the external force, respectively. Therefore, the phase shift of the periodic signal A input to the terminal T3 and the periodic signal B input to the terminal T4
The phase shift of is a phase shift in opposite directions.
In this way, the output signal Vy is derived by reading the phase shift of the periodic signal A and the periodic signal B input to the terminals T3 and T4, respectively, by the signal processing circuit using the logic element. The sign of this output signal Vy is
It indicates whether the Y-axis direction component of the external force is in the positive direction or the negative direction, and its absolute value indicates the magnitude of the Y-axis direction component.

Further, when the external force includes a Z-axis direction component, the electrostatic capacitance value of the capacitive element C5 changes, and the phase of the periodic signal A input to the terminal T5 shifts.
Further, since the capacitance value of the capacitive element C6 is kept constant, the phase of the periodic signal B input to the terminal T6 does not deviate. Therefore, the phase shift occurs only in the periodic signal A input to the terminal T5, and the output signal Vz is derived by reading the phase shift of the periodic signal A by the signal processing circuit using the logic element. This output signal V
The sign of z indicates whether the Z-axis direction component of the external force is in the positive direction or the negative direction, and its absolute value indicates the magnitude of the Z-axis direction component.

When the external force includes an X-axis direction component or a Y-axis direction component, the stick 30
Depending on how the force is applied to, the following cases are possible. For example, when considering the X-axis direction, the X-axis positive direction portion and the X-axis negative direction portion of the diaphragm 40 are not displaced in the directions opposite to each other, and the X-axis positive direction portion and the X-axis negative direction portion are both downward. Is displaced to, and
The respective displacement amounts at that time may be different. In this case, the respective phases of the periodic signal A and the periodic signal B input to the terminals T1 and T2 are deviated in the same direction. However, as in the case described above, the phase deviates. The output signal Vx is derived by reading with a signal processing circuit using a logic element. The same applies to the derivation of the output signal Vy in the Y-axis direction.

Next, in a state where no force is applied to the stick 30 shown in FIG. 1, as shown in FIG.
When the stick 30 is operated in the positive direction of the X-axis,
That is, consider a case where a force (a force in the negative direction of the Z-axis) that pushes down a portion of the diaphragm 40 corresponding to the positive direction of the X-axis toward the substrate 20 side is considered.

When a force in the positive X-axis direction is applied to the stick 30, the portion of the diaphragm 40 corresponding to the positive X-axis direction is pushed down, and the diaphragm 40 is elastically deformed. Since the diaphragm 40 is easily deformed in the recesses 41 to 45 having low rigidity, the deformation in each direction is concentrated in the recesses 41 to 45.

Regarding the X-axis positive direction, which is the direction of the force applied to the stick 30, the diaphragm 40 is deformed mainly in the recess 41, and the deflection is concentrated in that portion, so that the X-axis positive direction of the diaphragm 40. The part is displaced downward. Further, at this time, regarding the X-axis negative direction which is the direction opposite to the direction of the force applied to the stick 30,
The diaphragm 40 is deformed mainly in the concave portion 42, and the bending is concentrated in that portion, and the X-axis negative direction portion of the diaphragm 40 is displaced upward. That is, the X-axis positive direction portion and the X-axis negative direction portion of the diaphragm 40 are often displaced vertically opposite to each other with the substantially central position of the both as a fulcrum.

Therefore, the distance between the X-axis positive direction portion of the diaphragm 40 and the capacitance element electrode E1 becomes small, while the distance between the X-axis negative direction portion of the diaphragm 40 and the capacitance element electrode E2 becomes large. Then, the capacitance values of the capacitance elements C1 and C2, which have changed in the distance between the capacitance element electrodes E1 and E2 and the diaphragm 40, change. Here, in general, the capacitance value of the capacitive element is inversely proportional to the interval between the electrodes forming the capacitive element, and thus the capacitive element C1
Has a large electrostatic capacitance value, and the capacitive element C2 has a small electrostatic capacitance value. At this time, the phases of the periodic signal A and the periodic signal B input to the terminals T1 and T2 are deviated, and the output signal Vx is derived by reading the deviated phase.

At this time, also in the Y-axis direction, which is the direction orthogonal to the positive direction of the X-axis, the diaphragm 40 is deformed mainly in the recesses 43 and 44, and the deflection is concentrated in that portion, as in the X-axis direction. To do. That is, the deflection is concentrated on the recess 43 in the positive Y-axis direction, and the deflection is concentrated on the recess 44 in the negative Y-axis direction.

Here, the recesses 43, 4 of the diaphragm 40 are
The flexure caused in each of No. 4 is based on the twisting stress generated by the force in the positive direction of the X axis applied to the stick 30. Then, the deflection based on the twisting stress in the Y-axis positive direction and the Y-axis negative direction is as described above.
Since it is concentrated in the recesses 43 and 44, the amount of bending tends to be relatively large. Then, the concave portion 43 corresponding to the Y-axis positive direction of the diaphragm 40 and the concave portion 4 corresponding to the Y-axis negative direction.
The amount of deflection in No. 4 changes almost linearly with the magnitude of the force in the positive direction of the X axis. At this time, the Y-axis direction component of the output also changes substantially linearly with the magnitude of the force in the X-axis direction.

Therefore, the outputs of the X-axis, Y-axis and Z-axis are
Since the magnitude and direction of the acting force change substantially linearly, the magnitude of the force of each component of the X axis, the Y axis, and the Z axis can be obtained by calculation. Therefore, the degree of close contact between the diaphragm 40, the cover plate 70, and the spacer 60, that is, the variation in the fastening state between the screw 71 and the nut 72, the change in the fastening state over time, and the welding between the diaphragm 40 and the stick 30. It is possible to properly detect the X-axis direction component of the output regardless of the fixed state of the diaphragm 40 based on the condition.

Although the case where a force in the positive direction of the X axis is applied to the stick 30 has been described here, a case where a force in a direction other than the positive direction of the X axis is applied to the stick 30 is explained. Can be considered similarly to the above. Further, in the present embodiment, the total of 16 recesses 41 to 45 are evenly arranged in the diaphragm 40 in order to reduce the dependence of the deformed state of the diaphragm 40 on the direction of the force applied to the stick 30. Is. Therefore, no matter which direction the force is applied to the stick 30, the diaphragm 40 is deformed substantially symmetrically with respect to the direction of the acting force.

Next, a signal processing circuit for deriving the output signals Vx, Vy, Vz by the periodic signals A, B input to the terminals T1 to T6 will be described with reference to the drawings. FIG. 7 is a circuit diagram showing a signal processing circuit of the capacitance type sensor shown in FIG.

As described above, a periodic signal of a predetermined frequency is input to the terminals T1 to T6 from an AC signal oscillator (not shown). Inverter elements I1 to I6 and resistance elements R1 to R6 are connected to these terminals T1 to T6, respectively.
Inverter elements I1 to I6 and resistance element R from 1 to T6 side
They are connected in the order of 1 to R6. Further, EX-OR elements 81 to 83, which are logic elements of the exclusive-sum circuit, are connected to the output terminals of the resistance elements R1 and R2, the output terminals of the resistance elements R3 and R4, and the output terminals of the resistance elements R5 and R6, respectively. The output terminal is connected to the terminals T11 to T13. The output terminals of the resistance elements R1 to R5 are connected to the capacitance element electrodes E1 to E5, respectively, and form capacitance elements C1 to C5 with the diaphragm 40, respectively. Further, the diaphragm 40 is grounded via the terminal T0 (see FIG. 4).

From here, as an example, a method of deriving the output signal Vx of the X-axis direction component will be described with reference to FIG. FIG. 8A is a circuit diagram (a part of FIG. 7) showing a signal processing circuit for the X-axis direction component of the capacitance type sensor shown in FIG. 1. In this signal processing circuit, the capacitive element C1 and the resistive element R1, and the capacitive element C2 and the resistive element R2.
Each form a CR delay circuit. Terminal T1, T
The periodic signal (rectangular wave signal) input to 2 is C
A predetermined delay is generated by the R delay circuit and the EX-OR element 81 merges.

Further, as the inverter elements I1 and I2,
Since the same element is used, signals on different paths can be compared under the same condition. Here, the inverter elements I1 and I2 are elements that generate sufficient drive power to drive the CR delay circuit, and are elements that are logically meaningless. Therefore, if it is possible to supply a signal having a sufficient driving capability to the terminals T1 and T2, these inverter elements I1 and I2 may be omitted. Therefore, since FIG. 8B omits the inverter elements I1 and I2 included in the signal processing circuit of FIG. 8A, the circuit is completely equivalent to that of FIG. 8A. Conceivable.

Next, the waveform of the periodic signal at each terminal and each node of the circuit of FIG. 8 will be described with reference to FIG. FIG. 9 is a diagram showing waveforms of periodic signals at each terminal and each node of the signal processing circuit shown in FIG. Note that FIG. 9 is drawn by ignoring the influence of the inverter elements I1 and I2.

In the signal processing circuit of FIG. 8, terminals T1,
The periodic signal input to each T2 passes through the CR delay circuit to generate a predetermined delay,
Each is input to the EX-OR element 81. More specifically, the terminal T1 receives the periodic signal f (φ) (corresponding to the above-described periodic signal A), and the terminal T2 has the same period as that of f (φ) and the phase. A periodic signal f (φ + θ) (corresponding to the above-mentioned periodic signal B) having a deviation of θ is input (see FIG. 9). The periodic signal f (φ) input to the terminal T1 passes through the CR delay circuit including the capacitive element C1 and the resistive element R1 and reaches the node X1. At this time, the periodic signal at the node X1 is delayed by time a as shown in FIG. Similarly,
The periodic signal f (φ + θ) input to the terminal T2 passes through the CR delay circuit including the capacitive element C2 and the resistive element R2 and reaches the node X2. At this time, the periodic signal at the node X2 is delayed by the time b.

Here, the times a and b respectively correspond to the delay time in the CR delay circuit and are determined by the time constant of each CR. Therefore, the resistance elements R1 and R2
When the resistance values of A and B are the same, the values of the times a and b correspond to the capacitance values of the capacitive elements C1 and C2. That is, when the capacitance values of the capacitive elements C1 and C2 increase, the values of the times a and b also increase, and the capacitive elements C1 and C2 increase.
When the capacitance value of 1 becomes smaller, the values of times a and b also become smaller.

Strictly speaking, when the signal processing circuit includes the inverter elements I1 and I2, the periodic signals input to the terminals T1 and T2 can also be passed through the inverter elements I1 and I2, respectively. , Which is considered to cause a predetermined delay. However, as described above, since the same elements are used as the inverter elements I1 and I2, the delay times due to the inverter elements in the two paths are considered to be the same, and when input to the EX-OR element 81. Therefore, the description of the delay time due to the inverter element is omitted here.

As described above, the EX-OR element 81 is supplied with signals having the same waveform as the periodic signals at the nodes X1 and X2, and an exclusive logical operation is performed between these signals.
The result is output to the terminal T11. Here, the signal output to the terminal T11 is a rectangular wave signal having a predetermined duty ratio (see FIG. 9).

Now, consider the waveform of the periodic signal at each terminal and each node when the above-described stick 30 is operated in the positive direction of the X axis (see FIG. 6).
In this case, the signal processing circuit when the stick 30 is not operated is C1 ′ and C2 ′, which are the capacitive elements formed between the capacitive element electrodes E1 and E2 and the diaphragm 40 in the signal processing circuit in this case. The nodes and terminals at the same positions as the nodes X1 and X2 and the terminal T11 are designated as nodes X1 ′, X2 ′ and terminal T11 ′ (see FIG. 8).

At this time, in the signal processing circuit of FIG.
Similarly to the above, the terminal T1 receives the periodic signal f (φ), and the terminal T2 receives the periodic signal f (φ + θ) with the same period as f (φ) but a phase difference of θ. (See FIG. 9). Periodic signal f (φ) input to terminal T1
Is C composed of the capacitive element C1 ′ and the resistive element R1.
The node passes through the R delay circuit and reaches the node X1 ′. At this time, the periodic signal at the node X1 ′ has a delay of time a + Δa as shown in FIG. This is because the capacitance value of the capacitive element C1 ′ becomes larger than that of the capacitive element C1 and the time constant of the CR delay circuit becomes large. Similarly, the periodic signal f input to the terminal T2
(Φ + θ) passes through the CR delay circuit including the capacitive element C2 ′ and the resistive element R2 and reaches the node X2 ′. At this time, the periodic signal at the node X2 ′ has a delay of time b−Δb. This is the capacitive element C2 '
This is because the electrostatic capacitance value of is smaller than that of the capacitive element C2, and thus the time constant of the CR delay circuit is reduced.

As described above, the EX-OR element 81 is supplied with the signals having the same waveforms as the periodic signals at the nodes X1 'and X2', and the exclusive logical operation is performed between these signals. Is output to the terminal T11 '. Here, the signal output to the terminal T11 ′ is a rectangular wave signal having a predetermined duty ratio, and as shown in FIG. 9, when the stick 30 is not operated, the signal is output to the terminal T11 ′. The rectangular wave signal has a smaller duty ratio than the output rectangular wave signal.

Here, in the capacitance type sensor 1, as described above, when the diaphragm 40 is displaced with its substantially central position as a fulcrum, the capacitance values of the capacitance elements C1 'and C2' are When one becomes larger, the other becomes smaller. As a result, the time constant of the CR delay circuit formed by the respective capacitive elements C1 ′ and C2 ′ also changes, and the duty ratio of the output rectangular wave signal changes significantly, so that the force acting on the stick 30 is reduced. The detection can be easily performed.

The signal processing circuit (see FIG. 7) for deriving the output signal Vz of the Z-axis direction component causes a predetermined delay by passing only the signal input to the terminal T5 through the CR delay circuit. However, since the capacitance value of the capacitive element C6 in the CR delay circuit through which the signal input to the terminal T6 passes does not change, no delay occurs due to the CR delay circuit. In this way, even in the circuit in which only one signal is delayed, the force acting on the stick 30 can be easily detected in the same manner as described above.

As described above, the change in the capacitance value of each of the capacitance elements C1 and C2 is detected as the change in the duty ratio of the waveform at the terminal T11, and this signal is rectified by passing through the smoothing circuit. This duty ratio can be converted into a voltage value and used. Also, T11
If the high level (Hi) or low level (Lo) time of the signal in (1) is counted by a clock signal having a higher frequency, the duty ratio can be converted into a digital count value and used.

Here, the periodic signals f (φ) and f (φ + θ) of different phases respectively input to the terminals T1 and T2 are
It is generated by dividing the periodic signal output from one AC signal oscillator into two paths, providing a CR delay circuit (not shown) in one of the paths, and delaying the phase of the periodic signal passing through the CR delay circuit. The method of shifting the phase of the periodic signal is not limited to the method using the CR delay circuit, and any other method may be used.
Using two AC signal oscillators, periodic signals f (φ) and f (φ + θ) having different phases are generated, and terminals T1 and
You may input into each of T2.

Incidentally, the capacitance type sensor 1 of the present embodiment
Is used as a force sensor, and is preferably used as an input device such as a personal computer, a game, a mobile phone, or a device for detecting the presence or absence of contact with an object. When the capacitance type sensor 1 of the present embodiment is attached to a fingertip of a robot or the like, it is possible to detect the presence or absence of contact with an object (it can be used as a one-dimensional sensor) and further the object. It is also possible to detect the direction of contact with (it can be used as a three-dimensional sensor). Further, the capacitive sensor 1 according to the present embodiment is not limited to the case of being used as a force sensor, but may be used as another sensor such as an acceleration sensor.
The same effect as this embodiment can be obtained.

As described above, in the capacitance type sensor 1 of the present embodiment, the diaphragm 40 is the stick 3
By having the recesses 41 to 45 arranged on the circumference so as to include the region corresponding to 0 inside, when the force in the predetermined axial direction is applied to the stick 30, other output is provided. The axial component changes substantially linearly with the magnitude of the force in the predetermined axial direction. The other axial component of the output linearly changes with good reproducibility with respect to the magnitude of the force in the predetermined axial direction. Therefore, the directional component of the acting force is properly detected by performing the calculation using the output of each directional component. As a result, the influence of the fixed state of the diaphragm 40 is less likely to occur, and the individual difference of the sensor can be properly compensated by calculation.

Further, since the diaphragm 40 has the concave portions 41 to 45 formed on the circumference, the stick 30
However, regardless of the direction of the force applied from the outside, the diaphragm 40 can be deformed without directivity regardless of the direction of the force. Therefore, the sensitivity of the capacitance sensor 1 rarely changes depending on the direction of the force applied to the stick 30 due to the direction of deformation of the diaphragm 40. As a result, it is possible to obtain the capacitive sensor 1 having no directivity.

Further, in the diaphragm 40, the recesses 41 to 41 are formed.
45 is formed and is thin and recesses 41 to 45
The portions that are not formed and are thick are arranged alternately along the circumferential direction. Therefore, when a force is applied to the stick 30, the two parts have a twisted structure. Therefore, when the force is no longer applied to the stick 30 from the state in which the force is applied to the stick 30, the diaphragm 40 is formed by the restoring force of the twist structure when the concave portion is not formed and the concave portion is formed in an annular shape. It is easier to return to the original state (state without twisting) compared to the case where This allows the stick 30
The reaction to can be quick.

Further, the recesses 41 to 45 are formed by the diaphragm 4
0 is formed on the upper surface (the surface opposite to the surface facing the substrate 20), the recesses 41 to 45 face the capacitor element electrodes E1 to E5 on the lower surface of the diaphragm 40 (the surface facing the substrate 20). The distance between the diaphragm 40 and the capacitance element electrodes E1 to E5 is smaller than that in the case of being formed so as to be formed. Therefore, the diaphragm 40
And the capacitance elements C1 to C5 formed between the capacitance element electrodes E1 to E5 have a relatively large capacitance value, and the sensitivity of the sensor 1 can be improved.

Further, the diaphragm 40 has recesses 41 to 4
5 is formed, and the space between the diaphragm 40 and the capacitance element electrodes E1 to E5 formed on the substrate 20 is
There is no communication with the outside. Therefore, for example, as in the case where the diaphragm has a through hole or a notch that allows the space between the diaphragm and the electrode for the capacitive element formed on the substrate to communicate with the outside, dust and dirt are provided between the two. It is possible to prevent a malfunction from occurring due to the entry of. As a result, the dustproof property of the sensor 1 is ensured, and the reliability thereof can be improved. Further, when the diaphragm has the through hole or the notch as described above, the diaphragm is very easily deformed, and when a relatively small force is detected, the force is properly detected. Although the problem that a relatively large force cannot be detected occurs, in the sensor 1 of the present invention, the diaphragm 4
Since the recesses 41 to 45 are only formed in 0, the diaphragm does not become extremely easily deformed. Therefore, it is possible to obtain a (large-capacity) sensor that can detect a relatively large force.

Next, a first modification of the embodiment of the present invention will be described with reference to the drawings. FIG. 10 shows the first
FIG. 10 is a top view of a diaphragm of the capacitance type sensor according to the modified example.

The diaphragm 140 of the capacitance type sensor according to the first modification of FIG. 10 is different from the diaphragm 40 of the capacitance type sensor 1 of FIG.
Substantially fan-shaped recesses 41-45 are formed in the diaphragm 140, while circular recesses 141-145 are formed in the diaphragm 140.
Is formed. Since the other configurations are the same as those of the capacitance type sensor of FIG. 1, detailed description thereof will be omitted.

The upper surface of the diaphragm 140 (stick 3
On the same side as 0), a circular stick 30
Diaphragm 140 including an area corresponding to
Recesses 1 arranged on the same circumference centered on the center position of
41-145 are provided. Here, the recess 141 is formed at a position corresponding to the positive direction of the X-axis, and the recess 41 is formed.
2 is formed at a position corresponding to the negative direction of the X axis. Similarly, the recesses 143 and 144 are formed at positions corresponding to the Y-axis positive direction and the Y-axis negative direction, respectively. The recesses 145 are spaced from each other by the same distance between the recesses 141 and 143, between the recesses 143 and 142, between the recesses 142 and 144, and between the recesses 144 and 141. Two pieces are formed so that they are arranged (evenly).

Also in the capacitance type sensor according to the first modified example having such a configuration, the same effect as that of the capacitance type sensor 1 of the present embodiment can be obtained. The number, shape and arrangement of the recesses formed in the diaphragm are
It can be arbitrarily changed within a range in which the same effect as that of the present embodiment can be obtained.

Next, a second modification of the embodiment of the present invention will be described with reference to the drawings. FIG. 11 shows the second
FIG. 10 is a top view of a diaphragm of the capacitance type sensor according to the modified example.

The diaphragm 240 of the capacitance type sensor according to the second modification of FIG. 11 is different from the diaphragm 40 of the capacitance type sensor 1 of FIG.
While a plurality of substantially fan-shaped recesses 41 to 45 are formed in the diaphragm, one annular recess 2 is formed in the diaphragm 240.
41 is formed. Since the other configurations are the same as those of the capacitance type sensor of FIG. 1, detailed description thereof will be omitted.

The upper surface of the diaphragm 240 (stick 3
An annular recess 241 centered on the central position of the diaphragm 240 that includes the region corresponding to the stick 30 inside is provided on the same surface as 0).

Also in the electrostatic capacitance type sensor according to the second modified example having such a configuration, the same effect as the electrostatic capacitance type sensor 1 of the present embodiment can be obtained.

Next, a third modification of the embodiment of the present invention will be described with reference to the drawings. FIG. 12 shows the third
FIG. 10 is a top view of a diaphragm of the capacitance type sensor according to the modified example. FIG. 13 is an enlarged sectional view taken along line XIII-XIII in FIG.

The diaphragm 340 of the capacitance type sensor according to the third modification of FIG. 12 is different from the diaphragm 40 of the capacitance type sensor 1 of FIG.
Is formed with a plurality of concave portions 41 to 45 along the same circumference, whereas the diaphragm 340 is formed with three annular concave portions 341 to 343 arranged concentrically. is there. Since the other configurations are the same as those of the capacitance type sensor of FIG. 1, detailed description thereof will be omitted.

The upper surface of the diaphragm 340 (stick 3
On the surface on the same side as 0), three annular recesses 341 to 343 centering on the center position of the diaphragm 340 including the region corresponding to the stick 30 inside are provided. The recesses 341 to 343 are centered on the central position of the diaphragm 340, are spaced apart from each other, and are provided concentrically. Here, the concave portion 3
The portions 42 are formed outside the recess 341 by a predetermined distance, and the portions 343 are formed outside the recess 342 by a predetermined distance.

Also in the electrostatic capacitance type sensor according to the third modified example having such a configuration, the same effect as that of the electrostatic capacitance type sensor 1 of the present embodiment can be obtained. further,
A plurality of annular recesses 341 to 343 formed concentrically
The stress generated in the vicinity of each end of each of the stresses is the stress generated in the vicinity of both ends of one annular recess (see the recess 241 in the second modification as shown in FIG. 11) arranged on the same circumference. Compared to, it becomes smaller by being dispersed. Therefore, the stress generated near one end of the recesses 341 to 343 is reduced, and the durability of the diaphragm 340 is improved.

Although the case where three annular recesses having the same width are formed has been described here, the number of recesses can be arbitrarily changed, and
The width of each of the plurality of recesses may be different from each other.

Next, a fourth modification of the embodiment of the present invention will be described with reference to the drawings. FIG. 14 shows the fourth
It is a figure which shows arrangement | positioning of the some electrode formed on the board | substrate of the electrostatic capacitance type sensor which concerns on the modification.

Electrodes for capacitance elements E101 to E105 on the substrate 20 of the capacitance type sensor according to the fourth modification of FIG.
1 is different from the arrangement of the capacitive element electrodes E1 to E5 on the substrate 20 of the capacitive sensor 1 in FIG. 1 in that the capacitive sensor 1 in FIG. While the capacitive element electrodes E1 to E4 are provided in
The capacitance type sensor according to the fourth modification is that the capacitance element electrode E5 is provided outside the capacitance element electrodes E1 to E4. Since the other configurations are the same as those of the capacitance type sensor of FIG. 1, detailed description thereof will be omitted.

On the substrate 20, as shown in FIG. 14, the electrodes E101 to E101 for the capacitive element, which are substantially fan-shaped with the origin O as the center, are formed.
104, a ring-shaped capacitive element electrode E5 located outside the center of the origin O, and a ring-shaped reference electrode E0 located outside of the center of the origin O are formed. . Here, a pair of capacitance element electrodes E10
1 and E102 are arranged in line symmetry with respect to the Y axis while being separated in the X axis direction. Further, the pair of capacitive element electrodes E103 and E104 are arranged in line symmetry with respect to the X axis while being separated in the Y axis direction.

Here, the area ratios of the capacitance element electrodes E101 and E102 corresponding to the X-axis direction, the capacitance element electrodes E103 and E104 corresponding to the Y-axis direction, and the capacitance element electrode E105 corresponding to the Z-axis direction, respectively. Can be adjusted to adjust the sensitivity of the sensor.
That is, in each of the present embodiment and this modification, as shown in FIGS. 2 and 14, the area of each of the capacitance element electrode corresponding to the X-axis direction and the capacitance element electrode corresponding to the Y-axis direction. Are the same, the sensitivities in the X-axis direction and the Y-axis direction of the sensor are substantially the same. On the other hand, the area ratio of the capacitance element electrode corresponding to the Z-axis direction to the capacitance element electrode corresponding to the X-axis direction and the capacitance element electrode corresponding to the Y-axis direction is larger in this modification than in the present embodiment. Is getting bigger. Therefore, it is considered that the sensitivity of the sensor in the Z-axis direction is higher in this modification than in this embodiment.

[0102]

EXAMPLES Examples of the above-described embodiment will be described in detail below.

Here, the load characteristic test and the test result of the capacitance type sensor 1 according to the present invention will be described. The load characteristic is represented by the relationship between the magnitude of the load and the magnitude of the output when a load (force) is applied to the stick 30 of the capacitance type sensor 1 from the outside. .

In the load characteristic test, each direction component of the output when a predetermined load is applied in each of the X-axis direction, the Y-axis direction and the Z-axis direction is detected.
The numerical signs indicating the loads in each of the X-axis direction, the Y-axis direction, and the Z-axis direction indicate whether the load direction is the positive direction or the negative direction of each axial direction. Further, the X-axis direction component of the output will be referred to as "X-axis output", the Y-axis direction component of the output will be referred to as "Y-axis output", and the Z-axis direction component of the output will be referred to as "Z-axis output".

In the present embodiment, for example, in a load characteristic test in the Y-axis direction, first, 4.41 (N.cm), 8.82 (N.cm), 13.23 (N.cm), 8.23 (N.cm) in the positive Y-axis direction from the state where no load is applied. (N
cm), 8.82 (Ncm), 4.41 (Ncm) load is added in order,
The original load is restored. And
The X-axis output, the Y-axis output, and the Z-axis output in the state where each load is applied are detected.

Subsequently, in the same manner as described above, from the state where no load is applied, in the negative direction of the Y-axis, -4.41 (N · cm),-
8.82 (N ・ cm), -13.23 (N ・ cm), -8.82 (N ・ cm), -4.41 (N ・ cm)
The loads are sequentially added to restore the original unloaded state. Then, the X-axis output, the Y-axis output, and the Z-axis output in the state where each load is applied are detected.

Based on the test results obtained in this way, the Y-axis load characteristic, which is the relationship between the Y-axis load and each axial component of the output at that time, is derived. Also, X
The load characteristics in the axial direction and the Z-axis direction can also be derived by performing the same load characteristic test as described above. In this embodiment, only the test result of the load characteristic in the Y-axis direction will be shown. Here, in FIGS. 15 and 16, the X-axis output, the Y-axis output, and the Z-axis output when a load in the Y-axis direction is applied are circles (◯),
It is indicated by a square (□) and a triangle (△).

(Embodiment) The capacitance type sensor 1 in this embodiment has a diaphragm 40 having recesses 41 to 45 as shown in FIG. The diaphragm 40 has a thickness of 0.25 (mm), and the recesses 41 to 45 have a depth of 0.125 (mm). (Comparative Example) The capacitance type sensor in this comparative example has a flat plate-shaped diaphragm in which no recess is formed. The diaphragm thickness is 0.
It is 2 (mm).

Here, in Examples and Comparative Examples,
To compare sensors with the same load characteristics (rating),
The thickness of each diaphragm is different. That is, the recess 4
The diaphragm 40 in which Nos. 1 to 45 are formed has a relatively low rigidity, while the diaphragm in which no recess is formed has a relatively high rigidity. It is preferable to adjust the thickness by changing it.

The test results obtained by the above-mentioned load characteristic test are shown in FIGS.

From the above test results, the following can be understood. First, in the comparative example, as shown in FIG.
The Y-axis output changes almost linearly (in proportion) to the increase / decrease of the load in the Y-axis direction. In other words, the Y-axis output decreases as the Y-axis positive direction load increases (a negative value and its absolute value increases), and the Y-axis negative-direction load increases as the Y-axis output increases. The axis output is increasing (positive value and its absolute value is increasing), and the Y-axis output decrease rate (slope) and the Y-axis negative direction load when the Y-axis positive direction load increases. The increasing rate (slope) of the Y-axis output when increasing increases is almost the same.

On the other hand, neither the X-axis output nor the Z-axis output changes linearly with the increase or decrease of the load in the Y-axis direction. Regarding the X-axis output, the X-axis output decreases as the Y-axis positive direction load increases, and the X-axis output increases as the Y-axis negative direction load increases. The decrease rate of the X-axis output when the load in the positive axis direction increases and the increase rate of the X-axis output when the load in the negative Y-axis direction increases are not the same. Regarding the Z-axis output, the Z-axis output decreases as the load in the Y-axis positive direction increases, and the Z-axis output decreases as the load in the Y-axis negative direction increases. .

On the other hand, in the embodiment, FIG.
As shown in, the Y-axis output changes substantially linearly as the load increases or decreases in the Y-axis direction, as in the comparative example. On the other hand, the X-axis output and the Z-axis output are the same as the Y-axis output.
It changes almost linearly as the axial load increases and decreases. Regarding the X-axis output, the X-axis output decreases as the Y-axis positive direction load increases, and the X-axis output increases as the Y-axis negative direction load increases. The decrease rate of the X-axis output when the load in the positive direction increases and the increase rate of the X-axis output when the load in the Y-axis negative direction increases are almost the same. Regarding the Z-axis output, the X-axis output increases as the Y-axis positive direction load increases, and the X-axis output decreases as the Y-axis negative direction load increases.
The increase rate of the X-axis output when the load in the Y-axis positive direction increases and the decrease rate of the X-axis output when the load in the Y-axis negative direction increases are almost the same.

Thus, the recesses 41 to 41 as shown in FIG.
In the capacitance type sensor 1 having the diaphragm 40 in which 45 is formed, when a load in the Y-axis direction is applied, not only the Y-axis output but also the X-axis in the direction orthogonal to the Y-axis direction Similarly, the output and the Z-axis output change substantially linearly as the load in the Y-axis direction increases and decreases. It should be noted that such characteristics are not limited to the load characteristics in the Y-axis direction, and similar characteristics can be obtained in the load characteristics in the X-axis direction and the load characteristics in the Z-axis direction.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above-mentioned embodiments, and various design changes can be made within the scope of the claims. Is possible. For example,
In the above-described embodiment, the recesses 41 to 45 are provided on the upper surface of the diaphragm 40 (the surface opposite to the surface facing the substrate 20) so as to correspond to the capacitive element electrodes E1 to E4 on the substrate 20. However, the present invention is not limited to this, and the recess may be formed on the lower surface of the diaphragm (the surface facing the substrate), or on the upper surface or the lower surface of the diaphragm for the capacitive element on the substrate. It may be formed so as not to correspond to the electrode but to correspond to a region outside the capacitor element electrode. However, when the concave portion is formed on the lower surface of the diaphragm so as to correspond to the capacitive element electrode on the substrate, the distance between the diaphragm and the capacitive element electrode on the substrate is reduced by the depth of the concave portion. Becomes larger and the generated electrostatic capacity becomes smaller,
It is preferable that the recess is formed on the upper surface of the diaphragm as in the present embodiment.

Further, in the above-mentioned embodiment, the component of the force applied from the outside to the stick 30 in the X-axis direction, Y-axis.
The capacitance type sensor 1 capable of detecting the three components of the axial direction component and the Z-axis direction component has been described, but the present invention is not limited to this, and only the necessary two components or one component of the above three components can be detected. It may be anything.

Further, in the above-described embodiment, the case where the diaphragm 40 and the spacer 60 are formed of different members has been described, but the diaphragm and the spacer are integrally formed of the same member. May be.

In the above-described embodiment, the case where the diaphragm 40 is electrically connected to the grounded reference electrode via the spacer 60 has been described, but the present invention is not limited to this. 40 and reference electrode E0
A capacitance element is formed between the reference electrode and the diaphragm 40, which is grounded not by the direct contact with the reference electrode E0 but by the capacitive coupling by the capacitance element (having a function as a coupling capacitor). It may be electrically coupled to E0. In this case, the withstand voltage characteristic of the capacitance type sensor is improved, the sensor is hardly damaged by the flow of the spark current, and it is possible to prevent a defect such as a connection failure. It is possible to obtain a high capacitance type sensor.

Further, in the above-mentioned embodiment, the EX-OR is used.
Although the case where the signal processing circuit including the element is used has been described, the present invention is not limited to this, and the configuration of the signal processing circuit can be arbitrarily changed. Therefore, instead of the EX-OR element that performs an exclusive OR operation, a signal that includes an OR element that performs an OR operation, an AND element that performs an AND operation, and a NAND element that performs an AND operation and a NOT operation Processing circuitry may be used. In this case, when each member of the capacitance type sensor is made of a material having a very high sensitivity, the sensitivity of the capacitance type sensor is adjusted by the configuration of the signal processing circuit (here, the sensitivity is Can be lowered).

[0120]

As described above, according to the first aspect, the conductive member has the concave portion arranged on the circumference so as to include the region corresponding to the detection member inside, When a force in the predetermined axial direction is applied to the detection member, the other axial component of the output changes substantially linearly with the magnitude of the force in the predetermined axial direction. The other axial component of the output linearly changes with good reproducibility with respect to the magnitude of the force in the predetermined axial direction. Therefore, the directional component of the acting force is properly detected by performing the calculation using the output of each directional component. As a result, the influence of the fixed state of the conductive member is less likely to occur, and the individual difference of the sensor can be appropriately compensated by calculation.

Further, since the conductive member has the concave portion formed on the circumference, it can be applied to any direction of force regardless of the direction of the force applied from the outside to the detection member. The conductive member can be deformed without directivity. Therefore, the situation in which the sensitivity of the sensor varies depending on the direction of the force applied to the detection member due to the directionality of the deformation of the conductive member rarely occurs. as a result,
It is possible to obtain a sensor having no directivity.

According to the second aspect of the present invention, the conductive member is provided with recesses and is thin and thin portions and recesses are not formed and is thick, and are alternately arranged along the circumferential direction. I'm out. Therefore, when a force is applied to the detection member, the above two parts have a twisted structure. Therefore, when the force is no longer applied to the detection member from the state in which the force is applied, the conductive member is formed by the restoring force of the twisted structure when the recess is not formed and when the recess is formed in an annular shape. It is easier to return to the original state (state without twisting) as compared with the case of being twisted.
Thereby, the reaction with respect to the detection member can be made quick.

According to the third aspect of the present invention, the stress generated in the vicinity of each end of each of the plurality of concentric annular recesses is generated in the vicinity of both ends of one annular recess arranged on the same circumference. Compared with the stress that occurs, it becomes smaller by being dispersed. Therefore, the stress generated near one end of the recess is reduced, and the durability of the conductive member is improved.

According to the fourth aspect, since the recess is formed on the surface of the conductive member opposite to the surface facing the substrate, the recess faces the capacitor element electrode on the surface facing the substrate of the conductive member. Compared with the case where it is formed to
The space between the conductive member and the capacitance element electrode is reduced. Therefore, the capacitance value of the capacitive element formed between the conductive member and the capacitive element electrode becomes relatively large,
The sensitivity of the sensor can be improved.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a capacitance type sensor according to an embodiment of the present invention.

FIG. 2 is a diagram showing an arrangement of a plurality of electrodes formed on a substrate of the capacitance type sensor of FIG.

3 is a top view of a diaphragm of the capacitance type sensor of FIG. 1. FIG.

FIG. 4 is an equivalent circuit diagram for the configuration of the capacitance type sensor shown in FIG.

5 is an explanatory diagram for explaining a method of deriving an output signal from a periodic signal input to the capacitance type sensor shown in FIG.

6 is a schematic cross-sectional view of a side surface when the detection member of the capacitance type sensor shown in FIG. 1 is operated in the positive direction of the X axis.

FIG. 7 is a circuit diagram showing a signal processing circuit of the capacitance type sensor shown in FIG.

8A is a circuit diagram showing a signal processing circuit for an X-axis direction component of the capacitance type sensor shown in FIG. 1. FIG.
(B) is a circuit diagram showing a signal processing circuit equivalent to (a).

9 is a diagram showing waveforms of periodic signals at each terminal and each node of the signal processing circuit shown in FIG.

FIG. 10 is a top view of the diaphragm of the capacitance type sensor according to the first modification of the embodiment of the present invention.

FIG. 11 is a top view of the diaphragm of the capacitance type sensor according to the second modification of the embodiment of the present invention.

FIG. 12 is a top view of a diaphragm of a capacitance type sensor according to a third modification of the embodiment of the present invention.

13 is an enlarged sectional view taken along line XIII-XIII in FIG.

FIG. 14 is a diagram showing an arrangement of a plurality of electrodes formed on a substrate of a capacitance type sensor according to a fourth modification of the embodiment of the present invention.

15 is a diagram showing load characteristics in the Y-axis direction of the capacitance type sensor of FIG.

FIG. 16 is a diagram showing a load characteristic in the Y-axis direction of a conventional capacitance sensor.

FIG. 17 is a schematic sectional view of a conventional capacitance type sensor.

18 is a diagram showing an arrangement of a plurality of electrodes formed on a substrate of the capacitance type sensor of FIG.

[Explanation of symbols]

1 Capacitance type sensor 20 Substrate 30 Stick (detection member) 40, 140, 240, 340 Diaphragm (conductive member) 41-45, 141-145, 241, 341-343
Recesses E1 to E5, E101 to E105 Capacitance element electrode E0 Reference electrodes C1 to C5 Capacitance element

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2F051 AB06 BA07 DA03                 4M112 AA01 BA07 CA01 CA02 CA12                       DA03 DA04 DA18 EA11 EA14                       FA20                 5B087 AA02 BC02 BC12 BC19 BC26                       BC34 DD03

Claims (4)

[Claims] 1. A substrate, a detection member facing the substrate, a detection member located between the substrate and the detection member, and the detection member being displaced in a direction perpendicular to the substrate. A conductive member that is displaceable in the same direction and that has a concave portion formed on the circumference so as to include a region corresponding to the detection member inside, and the conductive member that is formed on the substrate. An electrode for a capacitive element that constitutes a capacitive element between, and a reference electrode that is formed on the substrate and electrically connected to the conductive member, and is grounded or held at a constant potential, A change in the capacitance value of the capacitance element due to a change in the distance between the conductive member and the capacitance element electrode is detected by using a signal input to the capacitance element electrode. It is possible to recognize the displacement of the detection member based on Capacitive sensors, characterized in Rukoto. 2. The capacitance type sensor according to claim 1, wherein the conductive member has a plurality of recesses arranged so as to be separated from each other along the circumference. 3. The capacitance type sensor according to claim 1, wherein the conductive member has a plurality of recesses that are concentrically arranged so as to be spaced apart from each other. 4. The electrostatic discharge according to claim 1, wherein the concave portion is formed on a surface of the conductive member opposite to a surface facing the substrate. Capacitive sensor.