JP2001311671A - Force-detecting element and force sensor using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect a force size with a simple structure. SOLUTION: Resistors R1, R2 and R5 are formed on a substrate 110. A displacement-generating body 120 of an insulating silicone rubber is prepared, and a fixing part 123 at the outer periphery of the generating body 120 is fixed with a fixing member 130 onto the substrate 110. A disk-shaped acting part 121 is supported from the periphery by a thin flexible part 122. Conductors C1, C2 and C5 for contact are formed of a conductive silicon rubber in a bowl form to a lower face of the acting part 21. When a force is applied to an operating rod 125, the acting part 121 is displaced, the contact state between each of the conductors for contact and each of the resistors changes, the contact area changes. Since resistance values at both ends of each resistor decrease the contact area of the conductor for contact, increases, the direction and the size of the acting force and detected from the change of these resistance values.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a force detector and a force sensor using the same, and more particularly, to a force detector suitable for use in input devices of computer games and small electronic devices, and a force sensor using the same. About.

[0002]

2. Description of the Related Art As a general force sensor, various types utilizing a piezoresistive element, a piezoelectric element, a capacitive element and the like are widely used. However, as an input device for a computer game, a simple structure is used. Inexpensive sensors are required. For this reason, as a game input device such as a so-called joystick, a switch-type sensor that electrically detects mechanical contact between a pair of terminals is widely used. Such a switch-type sensor has a simple structure for detecting whether or not a pair of terminals are in contact with each other, and has a low manufacturing cost.

[0003]

The above-mentioned switch type sensor has the advantages of a simple structure and low cost, but it has a binary value of ON / OFF whether or not an external force is applied. Only the state can be detected. Of course, it is often sufficient for such a simple input device for a computer game to have such an ON / OFF switch function. However, recently, the content of the computer game has been complicated, and a simple ON / OFF switch has been used. OF
There is a need for a sensor that can detect the magnitude of the force applied by the operator, not as an F switch. Also,
In recent years, the spread of small electronic devices such as mobile phones and portable electronic terminals has been remarkable, and even as input devices for such small electronic devices, inexpensive input devices that can detect the magnitude of force as an operation amount have been developed. Is desired.

Accordingly, an object of the present invention is to provide an inexpensive force detector and a force sensor which can detect the magnitude of an applied force and have a simple structure.

[0005]

(1) A first aspect of the present invention relates to a force detector for detecting an external force acting in the X-axis direction or an equivalent pressing force in an XYZ three-dimensional coordinate system. A substrate having an upper surface along an XY plane in a coordinate system, an operating portion disposed above the substrate, a fixing portion fixed to the substrate, and a flexible member formed between the operating portion and the fixing portion. And a first resistor disposed in the X-axis positive region and the X-axis negative region on the upper surface of the substrate, respectively, when the origin of the coordinate system is defined substantially at the center of the upper surface of the substrate. Body and a second resistor; a first contact conductor and a second contact conductor disposed at positions on the lower surface of the action portion facing the first resistor and the second resistor, respectively; When the external force acts on the action portion, the flexible portion bends. As a result, the lower surface of the action portion is displaced with respect to the upper surface of the substrate, and based on the displacement, the first resistor and the second resistor of the first contact conductor and the second contact conductor. The first contact conductor and the second contact conductor are made of a conductive material that is elastically deformed.
Further, it has a shape in which the area of the contact surface changes based on the change in the state of contact with the first resistor and the second resistor, and based on the change in the area of the contact surface, X It is possible to detect a pressing force that causes an external force acting in the axial direction or a displacement equivalent to the external force to the acting portion.

(2) The second aspect of the present invention relates to the above-described first aspect.
A force sensor is configured by adding a predetermined detection circuit to the force detector according to the aspect.
Here, the predetermined detection circuit includes a resistance value between two points sandwiching the “contact position of the first contact conductor” on the first resistor and a “second contact” on the second resistor. It has a function of detecting an external force acting in the X-axis direction or a pressing force equivalent to the external force by comparing a resistance value between two points sandwiching the “contact position of the conductor for use”.

(3) The third aspect of the present invention is the above-described second aspect.
In the force sensor according to the aspect, the first resistor and the second resistor are connected in series at the connection point for X-axis detection to form an X-axis detection resistor, and the X-axis detection resistor is formed. A predetermined voltage is applied to both ends of the sensor, and a detection circuit that outputs a value corresponding to the voltage of the connection point for X-axis detection as an external force applied in the X-axis direction or a value of a pressing force equivalent to the external force is used. It was done.

(4) The fourth aspect of the present invention is the above-mentioned first aspect.
In the force detector according to the aspect, the third resistor and the fourth resistor are respectively disposed in the Y-axis positive region and the Y-axis negative region on the upper surface of the substrate, and the third resistor on the lower surface of the action portion. And a third contact conductor and a fourth contact conductor arranged at positions facing the fourth resistor, respectively, so that the lower surface of the action portion is displaced with respect to the upper surface of the substrate. The contact state of the third contact conductor and the fourth contact conductor with respect to the third resistor and the fourth resistor is changed based on the third contact conductor and the fourth contact conductor. The contact conductor of No. 4 is made of a conductive material that is elastically deformed, and has a shape in which the area of the contact surface changes based on a change in the state of contact with the third resistor and the fourth resistor. And, based on the change in the area of the contact surface, To those it can detect the pressing force that causes the action part of the external force or the force equivalent displacement action in the Y-axis direction.

(5) The fifth aspect of the present invention relates to the above-described fourth aspect.
A force sensor is configured by adding a predetermined detection circuit to the force detector according to the aspect.
Here, the predetermined detection circuit includes a resistance value between two points sandwiching the “contact position of the first contact conductor” on the first resistor and a “second contact” on the second resistor. A function of detecting the external force applied in the X-axis direction or a pressing force equivalent to the external force by comparing the resistance value between two points sandwiching the “contact position of the conductive body”. Resistance between two points sandwiching the “contact position of the third contact conductor” and the resistance value between two points sandwiching the “contact position of the fourth contact conductor” on the fourth resistor And a function of detecting an external force applied in the Y-axis direction or a pressing force equivalent to the external force by comparing

(6) The sixth aspect of the present invention is the above-mentioned fifth aspect.
In the force sensor according to the aspect, the first resistor and the second resistor are connected in series at the connection point for X-axis detection to form an X-axis detection resistor, and the X-axis detection resistor is formed. And outputs a value corresponding to the voltage of the X-axis detection connection point as an external force applied in the X-axis direction or a value of a pressing force equivalent to the external force. A Y-axis detection resistor is formed by connecting a fourth resistor in series at the Y-axis detection connection point, and a predetermined voltage is applied to both ends of the Y-axis detection resistor to form a Y-axis detection resistor. A detection circuit that outputs a value corresponding to the voltage at the connection point as an external force applied in the Y-axis direction or a value of a pressing force equivalent to the external force is used.

(7) A seventh aspect of the present invention is the above-mentioned first aspect.
In the force detector according to the aspect, the Z-axis resistor disposed on the upper surface of the substrate and the Z-axis contact conductor disposed on the lower surface of the acting portion at a position facing the Z-axis resistor. And a contact state of the Z-axis contact conductor with respect to the Z-axis resistor is changed based on a displacement of the lower surface of the action portion with respect to the upper surface of the substrate. The body is made of a conductive material that is elastically deformed, and has a shape in which the area of the contact surface changes based on the change in the state of contact with the Z-axis resistor. Based on this, it is also possible to detect a pressing force that causes the acting portion to exert an external force acting on the acting portion in the Z-axis direction or a displacement equivalent to the external force.

(8) The eighth aspect of the present invention relates to the above-mentioned seventh aspect.
In the force detector according to the aspect, the Z-axis resistor and the Z-axis
The shaft contact conductor is arranged at a position crossing the Z axis.

(9) The ninth aspect of the present invention is the above-mentioned seventh aspect.
Alternatively, in the force detector according to the eighth aspect, a reference resistor is further provided on the upper surface of the substrate such that a resistance value between two predetermined points is constant without being affected by an external force or a pressing force. It is.

(10) According to a tenth aspect of the present invention, a force sensor is configured by adding a predetermined detection circuit to the force detector according to the ninth aspect. Here, the predetermined detection circuit includes a resistance value between two points sandwiching the “contact position of the first contact conductor” on the first resistor and a “second contact” on the second resistor. By comparing the resistance value between two points sandwiching the "contact position of the conductor for use",
A function of detecting an external force applied in the X-axis direction or a pressing force equivalent to the external force, a resistance value between two points sandwiching the “contact position of the Z-axis contact conductor” on the Z-axis resistor, By comparing the resistance value between two points where the resistance value is constant without being affected by external force or pressing force on the reference resistor, the external force applied in the Z-axis direction or equivalent to the external force And a function of detecting the pressing force of the

(11) According to an eleventh aspect of the present invention, in the force sensor according to the tenth aspect, the first resistor and the second resistor are connected in series at a connection point for X-axis detection. Thus, an X-axis detection resistor is formed, a predetermined voltage is applied to both ends of the X-axis detection resistor, and a value corresponding to the voltage of the X-axis detection connection point is applied to an external force applied in the X-axis direction or A pressing force value equivalent to the external force is output, and the Z-axis resistor and the reference resistor are connected in series at the Z-axis detecting connection point to form a Z-axis detecting resistor. A detection circuit that applies a predetermined voltage to both ends of the detection resistor and outputs a value corresponding to the voltage of the Z-axis detection connection point as an external force applied in the Z-axis direction or a value of a pressing force equivalent to the external force. It is intended to be used.

(12) A twelfth aspect of the present invention is the force detector according to the fourth aspect described above, wherein the Z-axis resistor disposed on the upper surface of the substrate and the Z-axis resistor on the lower surface of the action portion are provided. And a Z-axis contact conductor disposed at a position facing the resistor, wherein the Z-axis contact conductor is disposed on the Z-axis contact conductor based on a displacement of the lower surface of the operating portion with respect to the upper surface of the substrate. The contact state with the resistor is configured to change, the Z-axis contact conductor is made of a conductive material that is elastically deformed, and the contact surface of the contact surface is changed based on the change in the contact state with the Z-axis resistor. It has a shape in which the area changes, and based on the change in the area of the contact surface, an external force applied in the Z-axis direction or a pressing force equivalent to the external force can be detected.

(13) A thirteenth aspect of the present invention is the force detector according to the twelfth aspect, wherein the Z-axis resistor and the Z-axis contact conductor are located at positions intersecting the Z-axis. They are arranged.

(14) According to a fourteenth aspect of the present invention, in the force detector according to the twelfth or thirteenth aspect, the resistance value between two predetermined points on the upper surface of the substrate is equal to the external force or the pressing force. A reference resistor which is constant without being affected is further provided.

(15) In a fifteenth aspect of the present invention, a force sensor is configured by adding a predetermined detection circuit to the force detector according to the fourteenth aspect. Here, the predetermined detection circuit includes a resistance value between two points sandwiching the “contact position of the first contact conductor” on the first resistor and a “second contact” on the second resistor. By comparing the resistance value between two points sandwiching the "contact position of the conductor for use",
A function of detecting an external force applied in the X-axis direction or a pressing force equivalent to the external force, a resistance value between two points sandwiching the “contact position of the third contact conductor” on the third resistor, By comparing the resistance value between two points sandwiching the “contact position of the fourth contact conductor” on the fourth resistor, an external force acting in the Y-axis direction or a pressing force equivalent to the external force is applied. And a resistance value between two points sandwiching the “contact position of the Z-axis contact conductor” on the Z-axis resistor, and a “resistance value of external force or pressing force” on the reference resistor. By comparing the resistance value between two points that are “constant without being affected”, the external force acting in the Z-axis direction or a pressing force equivalent to the external force is provided.

(16) In a sixteenth aspect of the present invention, in the force sensor according to the fifteenth aspect, the first resistor and the second resistor are connected in series at a connection point for X-axis detection. Thus, an X-axis detection resistor is formed, a predetermined voltage is applied to both ends of the X-axis detection resistor, and a value corresponding to the voltage of the X-axis detection connection point is applied to an external force applied in the X-axis direction or A value of the pressing force equivalent to the external force is output, and a third resistor and a fourth resistor are connected in series at a Y-axis detection connection point to form a Y-axis detection resistor. A predetermined voltage is applied to both ends of the axis detecting resistor, and a value corresponding to the voltage at the Y-axis detecting connection point is output as an external force acting in the Y-axis direction or a value of a pressing force equivalent to the external force. The axis resistor and the reference resistor are connected in series at the Z-axis detection connection point. A Z-axis detection resistor is formed, a predetermined voltage is applied to both ends of the Z-axis detection resistor, and a value corresponding to the voltage of the Z-axis detection connection point is applied to an external force applied in the Z-axis direction or the external force. A detection circuit that outputs a value of a pressing force equivalent to an external force is used.

(17) According to a seventeenth aspect of the present invention, in the force detector or the force sensor according to the above-described first to sixteenth aspects, an operation rod is provided on the upper surface of the action portion, and the operation rod is provided via the operation rod. The lower surface of the action portion is configured to be displaced with respect to the upper surface of the substrate by the applied external force, so that the external force applied to the operation rod can be detected.

(18) According to an eighteenth aspect of the present invention, in the force detector or the force sensor according to the above-described first to sixteenth aspects, a plurality of indices are arranged on the upper surface of the action section, and each index position is The lower surface of the acting portion is displaced relative to the upper surface of the substrate by the pressing force applied to the substrate, so that it is possible to detect how much pressing force is applied to which index position. .

(19) According to a nineteenth aspect of the present invention, in the force detector or the force sensor according to any one of the first to sixteenth aspects, a weight is joined to the action portion to act on the weight. Configured so that an external force acts on the action portion based on the acceleration obtained,
By detecting the applied external force, the applied acceleration can be detected.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on an embodiment shown in the drawings.

§1. Of the force detector according to the basic embodiment
Structure FIG. 1 is a side sectional view showing a structure of a force detector according to a basic embodiment of the present invention. The force detector detects the external force acting on the XYZ three-dimensional coordinate system in the X-axis direction, the Y-axis direction,
It has a function of independently detecting each component in the Z-axis direction, and the main components are, as shown in FIG.
0, the displacement generator 120, and the fixed member 130. Here, for convenience of explanation, the origin O of the XYZ three-dimensional coordinate system is defined at substantially the center of the upper surface of the substrate 110,
Are arranged along the XY plane.
In the coordinate system shown in FIG. 1, the X axis is defined in the right direction of the figure, the Z axis is defined in the upward direction of the figure, and the Y axis is defined in the downward direction perpendicular to the page.

As described above, the substrate 110 is a flat rigid substrate having an upper surface along the XY plane.
In this embodiment, a glass epoxy substrate is used. In practicing the present invention, the material of the substrate 110 is not particularly limited, and any material may be used as long as the substrate has sufficient rigidity so as not to be deformed even under the action of a force described later. It doesn't matter. However, since it is necessary to form a plurality of resistors electrically independent from each other on the upper surface, it is necessary that at least the surface on which the resistors are formed has an insulating property. Therefore, in practice, it is preferable to use a glass epoxy substrate, a polyimide substrate, a glass substrate, or the like made of an insulating material. Of course, a metal plate can be used as the substrate 110, but in this case,
It is necessary to form an insulating film on at least the resistor forming portion on the upper surface.

FIG. 2 is a top view of the substrate 110.
The dashed-dotted rectangle indicates the displacement generator 12 disposed thereon.
The position of 0 is shown. The substrate 110 shown in FIG.
Is a cross section obtained by cutting the substrate 110 shown in FIG. 2 along the X-axis. The upper surface of the substrate 110 is included in the XY plane of the XYZ three-dimensional coordinate system, and the origin O is defined at the center. As shown, six resistors R1 to R6 are formed on the upper surface of the substrate 110. These resistors R
In this embodiment, 1 to R6 are resistors made of flat carbon. The resistor used in the present invention may be of any material as long as it has a resistance value suitable for measurement described below, and may be of any shape. Practically, it is preferable to use a plate-shaped resistor that can be formed on the upper surface of the substrate 110 by printing using a material such as carbon.

The important point here is that these resistors R1 to R1
This is the arrangement of R6. As shown in the drawing, the first resistor R1 is disposed in the X-axis positive region on the upper surface of the substrate 110,
The resistor R2 is disposed in a negative X-axis region on the upper surface of the substrate 110, the third resistor R3 is disposed in a positive Y-axis region on the upper surface of the substrate 110, and the fourth resistor R4 is disposed on the substrate 110. 11
It is arranged in the Y-axis negative region on the upper surface of the zero. Each of the four resistors R1 to R4 has a rectangular shape having the same size, and is arranged to be line-symmetric with respect to the X axis or the Y axis. Also, the origin O and each resistor R
The distances from 1 to R4 are also the same.
As will be described later, the first resistor R1 and the second resistor R2 are used for detecting an X-axis direction component of the applied external force, and the third resistor R3 and the fourth resistor R4 operate It is used for detecting the Y-axis direction component of the external force.

On the other hand, the fifth resistor R5 and the sixth resistor R6 are square plate-shaped resistors having the same size as each other. Here, the fifth resistor R5 is arranged so that its center point is located at the position of the origin O, whereas the sixth resistor R6 is arranged at the lower right of these resistor groups. Have been. As will be described later, the fifth resistor R5 and the sixth resistor R6 are used for detecting the Z-axis direction component of the applied external force. However, the original detection value of the Z-axis direction component is obtained from the fifth resistor R5, and the sixth resistor R6 is used only as a reference for a standard resistance value. Therefore, here, the fifth resistor R
5 is called a "Z-axis resistor", and the sixth resistor R6 is called a "reference resistor". The Z-axis resistor R5 is
In principle, it may be placed at any position on the upper surface of the substrate 110, but it is preferable to be placed at the position of the origin O (position intersecting the Z axis) in order to enhance detection sensitivity. This is because, due to the structure of the displacement generator 120 according to the present embodiment, the displacement at the central portion (the portion that intersects the Z axis) is the largest. On the other hand, the reference resistor R6
Is a resistor simply used to refer to a resistance value, and may be arranged at an arbitrary position on the substrate 110.

On the other hand, the displacement generating body 120
0 is a member arranged on the upper surface. This displacement generator 12
3 is a top view, and FIG. 4 is a bottom view thereof. A cross section of the displacement generator 120 shown in FIGS. 3 and 4 taken along the X axis is shown in FIG. As shown in FIG. 1, the displacement generating body 120 includes a disc-shaped acting portion 121 located inside and a flexible portion 122 around the acting portion 121.
And an outer fixed portion 123.
A column-shaped operation rod 125 having a Z-axis as a central axis is formed in a central portion of the upper surface of 1. As shown in the cross-sectional side view of FIG.
1, a stepped structure is formed by the flexible portion 122 and the fixed portion 123, and a cavity V is formed on the lower surface. Although the upper surface of the displacement generator 120 does not necessarily have to have such a stepped structure, in the case of the illustrated example, the stepped structure between the action portion 121 and the flexible portion 122 reduces the thickness of the flexible portion 122. It contributes to thinning. That is, the operation unit 121
By setting the thickness of the flexible portion 122 to be thinner than the thickness of the flexible portion 122, the flexible portion 122 has flexibility. The step structure between the flexible part 122 and the fixed part 123 is as follows.
This is a convenience for fixing the fixing portion 123 by the fixing member 130.

As described above, the displacement generator 120 according to the present invention includes the action section 121, the flexible section 122, and the fixed section 123.
Need to be provided. Here, the action section 12
1 may be basically in any form as long as it is disposed above the substrate 110 and has a structure that generates displacement by the action of an external force. It is necessary to mount the contact conductor at a predetermined position (a position facing each resistor). Therefore, it is preferable to adopt a disk-like form having a lower surface suitable for attaching the contact conductor. The action portion 121 does not need to be a completely rigid body, but preferably has a certain degree of rigidity as compared with the flexible portion 122. In this embodiment, the action portion 121 has a greater thickness than the thickness of the flexible portion 122. By increasing the wall thickness, a certain degree of rigidity is imparted.

The fixing portion 123 is a portion for fixing the displacement generator 120 to the substrate 110. In the illustrated example, the lower surface of the fixing portion 123 is in direct contact with the upper surface of the substrate 110. The fixing member 130 is a member having a function of fixing the fixing portion 123 to the substrate 110, and
It has a structure that surrounds the zero and displacement generator 120 from its outer peripheral portion, and keeps the upper surface of the fixed part 123 and the lower surface of the substrate 110 sandwiched therebetween. Note that the fixing portion 123 does not necessarily need to be directly fixed to the substrate 110,
It may be indirectly fixed between the substrate and the substrate 110 via some intermediate member.

The flexible section 122 is composed of the action section 121 and the fixed section 1.
23, and has flexibility. Since the flexible portion 122 has flexibility, the action portion 12
When an external force acts on 1, the flexible portion 122 is bent, and the acting portion 121 is displaced with respect to the substrate 110. The external force is actually given to the operation rod 125. For example, if this force detector is used as a part of a joystick for a computer game, an external force given by the operator operating the operation rod 125 is transmitted from the operation rod 125 to the flexible part via the action part 121. 1
The flexible portion 122 is bent in accordance with the external force, and the action portion 121 is displaced. The degree of flexibility of the flexible part 122 is a parameter that determines the relationship between the magnitude of the force applied by the operator and the magnitude of the displacement generated in the action part 121. In the illustrated example, the outer shape of the hollow portion V is rectangular, but the outer shape of the hollow portion V may be circular. In this case, the flexible portion 122 has an annular shape (a donut shape).

In this embodiment, the entire displacement generator 120 is formed by integrally molding insulating silicon rubber, and the action portion 121, the flexible portion 122, and the fixed portion 12 are formed.
3. The operation rod 125 is made of insulating silicon rubber. In the displacement generator 120 used in the present invention,
Since at least the flexible part 122 only needs to have flexibility, each part of the displacement generator 120 can be made of a different material. However, in order to reduce the manufacturing cost, it is preferable that the entirety of the displacement generator 120 be formed as an integrally molded product of the same material such as insulating silicon rubber.

A portion shown by a broken line in the top view of FIG. 3 is a cavity V formed on the lower surface of the displacement generator 120. As shown in the bottom view of FIG. 4, five contact conductors C1 to C5 are accommodated inside the hollow portion V. Each of the contact conductors C1 to C5 is bowl-shaped (more precisely, the contact conductors C1 to C4 are hemispherical, and the contact conductor C5 is semielliptical), and are elastically deformed. It is made of a conductive material. Here, conductive silicon rubber is used as the conductive material that is elastically deformed, and each of the contact conductors C1 to C5 is formed by molding conductive silicon rubber into a bowl shape and bonded to the lower surface of the displacement generator 120. It was done. Here, the arrangement of the contact conductors C1 to C5 is important. That is, the contact conductors C1 to C5 are arranged at positions facing the resistors R1 to R5, respectively. In the side sectional view of FIG. 1, the contact conductors C1, C2, C
5 is clearly shown at a position facing the resistors R1, R2, and R5, respectively. In this embodiment, in the state where no external force acts, each of the contact conductors C1 to C5 is connected to each of the resistors R
The distance between the two is set so that the upper surfaces of 1 to R5 are almost in point contact with each other. It should be noted that no contact conductor is provided at a position facing the reference resistor R6. This is because, as described above, the reference resistor R6
Is a resistor used to refer to the resistance value.

As described above, when an external force acts on the operating rod 125, the flexible portion 122 is bent, and the lower surface of the operating portion 121 is displaced with respect to the upper surface of the substrate 110. When such a displacement occurs, the contact state of each conductor for contact with each resistor changes. More specifically, the area of the contact surface of each contact conductor with respect to each resistor changes. The basic principle of the force detector according to the present invention is that the area of such a contact surface is detected as a change in the resistance value of the resistor, and the magnitude of the applied external force is determined. Hereinafter, the basic principle of detecting the components of the applied external force in the direction of each coordinate axis will be described.

§2. Of the force detector according to the basic embodiment
Operating principle Now, as shown in the side sectional view of FIG. 5 (a), 1 sheet of the resistor R is formed on the upper surface of the substrate 110, the action part 12
It is assumed that a hemispherical contact conductor C is formed on the lower surface of the contact conductor 1. At this time, it is assumed that the contact conductor C is substantially in point contact with the center of the resistor R at the lower end point. FIG. 5B is a top view of the resistor R at this time, and the black circle S shown at the center position indicates the contact surface of the contact conductor C. As described above, when the lower end point of the contact conductor C is almost in point contact with the surface of the resistor R, the contact surface S is a minute circle close to a point.

Now, as shown in FIG. 5 (b), wires are drawn out from the left and right ends of the resistor R, and terminals T1 and T2 are connected to the ends of these wires.
Suppose that the resistance value between them was measured. In other words, the resistance value between two points sandwiching the “contact position (contact surface S) of the contact conductor C” on the resistor R is measured. in this case,
Since the contact surface S is a small circle close to a point, the contact conductor C hardly affects the resistance value to be measured, and the resistance value obtained by the measurement is the original resistance of the resistor R. This means a value close to the resistance value. Fig. 5 (c)
Is an equivalent circuit of such a measurement system. The arrow extending downward from the contact conductor C only contacts the center point of the resistor R, and the resistor R is located between the terminals T1 and T2.
Only the original resistance value of.

On the other hand, as shown in the side sectional view of FIG. 6A, a downward force -Fz (force in the -Z axis direction) is applied to the acting portion 121 in the figure. Consider the case of joining. In this case, the lower surface of the action portion 121 is displaced downward, and a pressing force in the −Z axis direction is applied to the contact conductor C. Since the contact conductor C is made of a conductive material (conductive silicon rubber in this example) that is elastically deformed, the contact conductor C is crushed as shown in FIG. The contact state changes.
The shape of the contact conductor C is a shape in which the area of the contact surface changes (a hemisphere in this example) based on such a change in the contact state. When C is crushed in the vertical direction, the area of the contact surface increases. FIG. 6B is a top view of the resistor R at this time, and a circle S indicates a contact surface of the conductor C for contact. The concentric circle drawn inside the circle S is a resistor R
2 is an isobar showing the distribution of pressure applied to the surface of the. That is, the contact pressure increases toward the center of the circle S.

As described above, when the contact surface of the contact conductor C increases, the resistance between the two terminals T1 and T2 changes. That is, since the contact conductor C is a conductor and has a property that current is much easier to flow than the resistor R, the current flowing between the terminals T1 and T2 is reduced at the contact surface portion indicated by the circle S. Would bypass the inside of the contact conductor C without passing through the resistor R. FIG. 6C is an equivalent circuit of such a measurement system.
Two arrows extending downward from the contact conductor C indicate the resistor R
And the current is diverted to the contact conductor C side at these two locations. The interval between the two arrows increases according to the size of the contact surface of the contact conductor C. As a result, the larger the area of the contact surface of the contact conductor C with the resistor R, the smaller the resistance value between the two terminals T1 and T2.

As described above, as the external force -Fz applied to the action portion 121 increases, the area of the contact surface of the contact conductor C increases, and the resistance value between the terminals T1 and T2 decreases. A linear relationship does not always hold between the applied external force and the resistance value between the two terminals, but if a univalent functional relationship holds between the two and the resistance value between the two terminals can be measured, the effect will be obtained. The magnitude of the applied external force can be obtained. This is the basic principle of force detection in the force detector according to the present invention.

Next, the reason why the force detector of the embodiment described in §1 can detect the components of the applied external force in the X-axis, Y-axis, and Z-axis directions will be described. First, let us consider a case where an external force F obliquely to the lower right direction acts on the operation rod 125 of the force detector shown in FIG. When this force detector is used as a joystick,
When the operation of inclining 25 to the right is performed, such an external force F acts. The side sectional view of FIG. 7 shows a state of displacement of the acting portion 121 when such an external force F acts. When the external force F is applied, the flexible portion 122 having flexibility bends. However, since the external force F is an obliquely downward rightward force, as shown in FIG. Is displaced so as to be inclined in the lower right direction. Decomposing the external force F into force components in the direction of each coordinate axis,
Fz (force in the -Z axis direction) and rightward force + Fx (+ X
Axial force). Here, the principle of detecting a component + Fx in the + X-axis direction among these components will be described.

When the external force F is taken as a force acting on the origin O of the coordinate system, actually, a force component in the X-axis direction +
Fx is a moment about the Y axis,
If the operator regards the force given to the operating rod 125 as +
The force component + Fx in the X-axis direction is a force directed in the + X-axis direction. As described above, the force and the moment indicate substantially the same physical quantity, and in this specification, a description unified in terms of a force will be given below.

When an external force F including a component + Fx in the + X-axis direction is applied, as shown in FIG. 7, the disc-shaped acting portion 121 is displaced so as to be inclined in the lower right direction. Therefore, when the degree of collapse of the contact conductors C1 and C2 arranged on the X axis is compared, the degree of collapse of C1 is larger than that of C2. Therefore, R1 of C1
Is larger than the contact area of C2 with R2. Therefore, for example, if the resistance values at both ends of the resistors R1 and R2 in FIG. 7 are measured, the resistance value of the resistor R1 is smaller than the resistance value of the resistor R2. The greater the difference between the two resistance values, the greater the X-axis component of the applied external force.

Contrary to the above-described example, the operator operates the operating rod 125.
Is performed obliquely to the lower left direction, a downward force −Fz (−Z-axis direction force) and a leftward force −Fx (−
(Force in the X-axis direction) is applied, and the disc-shaped acting portion 121 is displaced so as to be inclined in the lower left direction. Therefore, the contact area of C2 with R2 is
It is larger than the contact area of C1 with R1. As a result, the resistance value of the resistor R2 is smaller than the resistance value of the resistor R1. As a result, the first resistor R1 disposed in the X-axis positive region has a resistance value between two points sandwiching the “contact position of the first contact conductor C1” and the second resistor R1 disposed in the X-axis negative region. By comparing the resistance value between two points sandwiching the “contact position of the second contact conductor C2” for the second resistor R2, it is possible to detect the X-axis direction component of the applied external force. become. That is, the direction of the force (+ X axis direction or −X axis direction) can be recognized from the magnitude relationship between the two resistance values, and the magnitude of the force can be recognized from the difference between the two resistance values.

The principle of detecting the Y-axis component of the applied external force is exactly the same as the principle of detecting the X-axis component described above. As shown in FIG. 2, six resistors R1 to R6 are arranged on the substrate 110. To detect the X-axis direction component, as described above, the first resistor R1 disposed in the X-axis positive region and the second resistor R2 disposed in the X-axis negative region
And a first contact conductor C1 and a second contact conductor C2 disposed at positions facing these. On the other hand, to detect the Y-axis direction component, the third resistor R3 disposed in the Y-axis positive region and the fourth resistor R4 disposed in the Y-axis negative region, Contact conductor C3 and fourth contact conductor C4 arranged in
May be used.

On the other hand, the principle of detecting the Z-axis component of the applied external force is slightly different from the principle of detecting the X-axis component and the Y-axis component described above. In order to perform detection in the X-axis direction and the Y-axis direction, it was necessary to compare the resistance values of a pair of resistors arranged on both sides of the origin O, whereas detection in the Z-axis direction It is possible to perform the measurement simply by measuring the resistance value of a single resistor. In addition, the arrangement of the resistors used for the detection in the Z-axis direction is not limited to a specific position, but the Z-axis component of the force applied by the resistor disposed at an arbitrary position on the upper surface of the substrate 110 is also possible. Can be detected. For example, in FIG.
The principle of detecting the X-axis direction component + Fx has been described. However, the external force F also includes the Z-axis direction component -Fz, and the force for crushing the contact conductor C1 in the vertical direction is It is nothing but the action of the component -Fz. In other words, the resistor C1
The direct reason for the decrease in the resistance value of the resistor C1 is that the Z-axis component -Fz acts. The amount of decrease in the resistance value of the resistor C1 is primarily due to the effect on the resistor C1. This indicates the magnitude of the force in the Z-axis direction component. The X-axis direction component + Fx can be detected by the above-described principle because the contact conductors C arranged on the left and right of the drawing.
This is because the fact that forces in the Z-axis direction applied to C1 and C2 are unbalanced in the left and right directions.

As a result, it is possible to detect a force component in the Z-axis direction based on the resistance value of the resistor R1. Similarly, it is possible to detect the force component in the Z-axis direction using any of the resistors R2, R3, and R4. However, in practice, it is preferable to dispose a dedicated resistor for detecting the force component in the Z-axis direction at a position where the most efficient detection can be performed. Therefore, in the present embodiment, as shown in the top view of FIG. 2, the fifth resistor R5 disposed on the origin O is used as a Z-axis resistor, and the Z-axis resistor is disposed above the fifth resistor R5. The contact conductor C5 is disposed. That is, both the Z-axis resistor R5 and the Z-axis contact conductor C5 are arranged on the Z-axis. In FIG. 1, when a force −Fz in the −Z-axis direction is applied to the operation rod 125, the Z-axis contact conductor C <b> 5 arranged to make point contact with the Z-axis resistor R <b> 5 is crushed, A change occurs in the contact state. That is, FIG.
As shown in (2), the contact area increases. Here, if the resistance value between two points sandwiching the “contact position of the Z-axis contact conductor C5” on the Z-axis resistor R5 is measured, the measured resistance value becomes the Z-axis contact conductor. Since the relationship decreases as the contact area of the body C5 increases, the applied -Z-axis direction force -Fz can be obtained based on the measured resistance value.

When this force detector is used for a joystick or the like, the force in the Z-axis direction generated by the operation applied to the operation rod 125 by the operator is usually a force in the -Z-axis direction -Fz (see FIG. 1). + Z)
It is not necessary to measure the axial force + Fz (the upward force in FIG. 1). However, when this force detector is used in an environment in which a force that pulls the operation rod 125 upward is applied, it is necessary to have a configuration capable of measuring the force + Fz in the + Z-axis direction. In fact, in the configuration shown in FIG.
The force + Fz in the Z-axis direction cannot be measured. already§
As described in FIG. 1, in the embodiment shown in FIG. 1, each of the contact conductors C1 to C5 in a state where no external force is applied.
The distance between them is set such that the lower end point thereof is in such a state as to make almost point contact with the upper surface of each of the resistors R1 to R5. In such a configuration, the operating rod 125
When a force is applied to pull the contact conductors upward, the contact conductors C1 to C5 rise from the upper surfaces of the resistor elements R1 to R5 and become in a non-contact state. Therefore, +
Even if a force + Fz in the Z-axis direction acts, each of the resistors R1 to R5
Will not change at all.

In order to make it possible to detect even a force + Fz in the + Z-axis direction, even if no external force is applied, each of the contact conductors C1 to C5 must be capable of detecting the force + Fz. What is necessary is just to make it the state which comes in surface contact with the upper surface of each resistor R1-R5 with a certain pressing force. With such a configuration, when a force + Fz in the + Z-axis direction acts, the contact area with the resistor decreases, and the force acting in the form of an increase in the resistance value of the resistor is detected. Will be able to

As described above, the detection of the component in the Z-axis direction can be performed by using only the single resistor R5 for the Z-axis. However, in practice, the detection is performed using the resistor R6 for reference. Is preferred. The reason is that a general resistor has a property that its own resistance value changes depending on various environmental factors. For example, if the chemical composition changes due to aging, the resistance value will change. In practice, the most important environmental factor is temperature. The resistance value of a general resistor changes depending on the temperature. Therefore, if the Z-axis direction component of the applied force is detected based only on the resistance value of the Z-axis resistor R5, the detected value is likely to be affected by the temperature,
Accurate detection results cannot be obtained. X mentioned above
In the case of the axial component and the Y-axis component, the detection based on the difference between the resistance values of the pair of resistors is performed, and thus the influence of such temperature is canceled. Therefore, when detecting the component in the Z-axis direction, if the detection is performed with reference to the resistance value of the reference resistor R6, the influence of the temperature can be canceled.

In the case of the example shown in FIG. 2, the Z-axis resistor R5 and the reference resistor R6 are resistors having a geometrically congruent shape, and the resistance value changes depending on the environment such as temperature. Are equivalent. The only difference between the two is whether the resistance value changes due to the action of an external force. That is, the resistor R5 for the Z-axis is a resistor whose resistance value between two predetermined points (two points sandwiching the contact position of the conductor C5 for the Z-axis contact) changes by the action of an external force. , Reference resistor R6
Means that the resistance value between two predetermined points is constant without being affected by external force (this means that the resistance value does not change with respect to the influence of external force; Changes). Therefore, if the difference between the two resistance values is detected, this difference includes:
Only factors based on the action of external forces will be included, and environmental factors such as temperature can be excluded.

As described above, using the force detector according to the embodiment shown in FIG.
The principle of detecting the directional components of the axis and the Z axis has been described. As described above, the force detector shown in FIG. 1 is a three-dimensional force detector that can detect a force in each of three-dimensional coordinate axis direction components. In this three-dimensional force detector, each resistor R1 shown in FIG.
To R6 and the contact conductors C1 to C5 shown in FIG.
Each of them is responsible for detecting a force in a specific coordinate axis direction component. That is, the resistors R1, R2 and the contact conductors C1, C2 are responsible for detecting the X-axis direction component, the resistors R3, R4 and the contact conductors C3, C4 are responsible for detecting the Y-axis component, and the Z-axis The resistor R5 for reference, the resistor R6 for reference, and the conductor C5 for contact with the Z-axis are responsible for detecting the component in the Z-axis direction.

Accordingly, a two-dimensional force detector capable of detecting the force of the two-dimensional coordinate axis component and a one-dimensional force detector capable of detecting the one-dimensional coordinate component force are configured. If so, it is sufficient to use only those necessary for detection among the above-described resistors and contact conductors. For example, in order to realize a one-dimensional force detector that detects a force in the X-axis direction component, it is sufficient to use the resistors R1 and R2 and the contact conductors C1 and C2. Further, in order to realize a two-dimensional force detector that detects the X-axis direction component and the Y-axis direction component, resistors R1, R2, R3, R4 and contact conductors C1, C2, C3, C4 are prepared. In order to realize a two-dimensional force detector for detecting the X-axis direction component and the Z-axis direction component, the resistors R1, R2, R5, R6
It is sufficient to prepare the contact conductors C1, C2, and C5.

§3. Detection Circuit as Force Sensor The configuration and operation principle of the force detector according to the basic embodiment of the present invention have been described above. In order to configure an actual force sensor using such a force detector, it is necessary to add a predetermined detection circuit to the force detector. here,
An example suitable for practical use of such a detection circuit will be described. FIGS. 8A, 8B and 8C are circuit diagrams showing an example of such a detection circuit.

First, the circuit shown in FIG.
1, a detection circuit that outputs a detection value of a component in the X-axis direction of a force to an output terminal Tx using R2. In this detection circuit, an X-axis detection resistor is formed by connecting a first resistor R1 and a second resistor R2 in series at an X-axis detection connection point Jx. The first resistor R1 or the second resistor R1
As shown in FIG. 5 (b), the both end points of the resistor R2 are the center points on the left and right short sides of the rectangular resistor so that the current flows in the left and right direction in the figure. I have to. Of course, any two end points may be used as both end points of each resistor R so as to sandwich the contact position of the contact conductor C. For example, as shown in FIG.
In this case, the current may flow in the vertical direction in the figure by setting the center point on both the upper and lower long sides of the rectangular resistor.

In the circuit of FIG. 8A, the X-axis detecting resistor formed by connecting the first resistor R1 and the second resistor R2 in series has an upper end connected to the power supply Vcc and a lower end. Are grounded, and a constant power supply voltage Vcc is applied to both ends. Here, the voltage output to the output terminal Tx is the voltage at the connection point Jx for X-axis detection, and the power supply voltage Vcc is changed by the resistance value of the first resistor R1 and the resistance value of the second resistor R2. It is equivalent to the value apportioned with the value. As described in §2, + force in X-axis direction +
When Fx is added, the resistance value of the first resistor R1 decreases as compared with the resistance value of the second resistor R2. Therefore, the voltage output to the output terminal Tx increases. Conversely, when a force -Fx in the -X-axis direction is applied, the voltage output to the output terminal Tx decreases. After all, when no external force is applied, the output terminal T
When the voltage value increases with reference to the voltage value output to x (theoretically becomes Vcc / 2), a force in the X-axis direction + F having a magnitude corresponding to the increase width
This means that x has acted, and if this voltage value has dropped, it means that a force -Fx in the X-axis direction having a magnitude corresponding to this drop width has acted. Thus, FIG.
, It is possible to detect the X-axis direction component of the applied external force based on the output voltage of the output terminal Tx.

Next, the circuit shown in FIG.
3, a detection circuit that outputs a detected value of a component in the Y-axis direction of the force to an output terminal Ty using R4. In this detection circuit, the Y-axis detection resistor is formed by connecting the third resistor R3 and the fourth resistor R4 in series at the Y-axis detection connection point Jy. The first resistor R1 or the second resistor R1
The two end points of the resistor R2 may be any end points as long as they sandwich the contact position of the contact conductor C. In the circuit shown in FIG.
Is connected in series with the resistor R3 and the fourth resistor R4, the upper end of which is connected to the power supply Vcc, the lower end is grounded, and a constant power supply voltage Vcc is set at both ends. The state is applied. The principle that the detection circuit can detect the Y-axis direction component of the applied external force based on the output voltage of the output terminal Ty is shown in FIG.
This is the same as the detection principle of the X-axis direction component by the detection circuit.

On the other hand, the circuit shown in FIG.
5, a detection circuit that outputs a detected value of a component in the Z-axis direction of the force to an output terminal Tz using R6. In this detection circuit, Z
The Z-axis detection resistor is formed by connecting the axis resistor R5 and the reference resistor R6 in series at the Z-axis detection connection point Jz. The two end points of the Z-axis resistor R5 may be any end points as long as they sandwich the contact position of the Z-axis contact conductor C5.
Further, the both ends of the reference resistor R6 may be located at positions equivalent to the both ends of the Z-axis resistor R5.

Also in the circuit of FIG. 8C, the Z-axis detecting resistor formed by connecting the Z-axis resistor R5 and the reference resistor R6 in series has the upper end connected to the power supply Vcc. The lower end is grounded and both ends have a constant power supply voltage Vc.
c is applied. Here, the output terminal T
The voltage output to z is the voltage at the Z-axis detection connection point Jz, and is a value obtained by dividing the power supply voltage Vcc by the resistance value of the Z-axis resistor R5 and the resistance value of the reference resistor R6. Is equivalent to As described in §2, the resistance value of the Z-axis resistor R5 increases or decreases due to the action of the force in the Z-axis direction. On the other hand, the resistance value of the reference resistor R6 is constant irrespective of the action of the force (of course, it changes under the influence of temperature, etc., but this change is the same for the Z-axis resistor R5). And are offset). For example, when a force -Fz in the -Z-axis direction is applied, the contact area of the Z-axis contact conductor C5 increases, and the resistance value of the Z-axis resistor R5 decreases. As a result, the output voltage of the output terminal Tz increases. In addition, the force in the + Z axis direction + F
If a force detector having a configuration capable of detecting z is used, when a + Z-axis force + Fz is applied, the contact area of the Z-axis contact conductor C5 decreases, and the Z-axis resistor R5 Will increase. As a result, the output voltage of the output terminal Tz decreases. As described above, by using the detection circuit of FIG. 8C, it is possible to detect the Z-axis direction component of the applied external force based on the output voltage of the output terminal Tz.

As described above, if the detection circuits shown in FIGS. 8A, 8B, and 8C are added to the three-dimensional force detector described in §1, the external force acting on the XYZ three-dimensional coordinate system can be obtained. X of F
A three-dimensional force sensor having a function of independently detecting the directional components of the axes, the Y axis, and the Z axis can be configured. Of course, when forming a one-dimensional force sensor or a two-dimensional force sensor, it is sufficient to use only a necessary detection circuit according to a detection component from the three detection circuits shown in FIG.

§4. Various Modifications Subsequently, some modifications of the force detector or the force sensor according to the present invention will be described.

(1) Modified Example to Give Click Feeling at the Time of Operation The modified example shown in a side sectional view in FIG. 9 is basically the same as the embodiment shown in FIG. That is, the displacement generator 220 is disposed on the substrate 210, and both are fixed by the fixing member 230 around the periphery. Displacement generator 2
20 has three parts, an action part 221, a flexible part 222, and a fixed part 223. Six resistors R1 to R6 are arranged on the upper surface of the substrate 210, and The same applies to the arrangement of the two contact conductors C1 to C5. However, the flexible portion 222 in the force detector of FIG. 9 has a structure that is considerably thinner than the flexible portion 122 of the force detector of FIG. 1 and extends upward. Therefore, when no external force is applied,
The distance between the upper surface of the substrate 210 and the lower surface of the action portion 221 is considerably large, and the contact conductors C1 to C5 are completely separated from the resistors R1 to R5.

Further, on the upper surface of the operation portion 221, there is no such thing as an operation stick, and the operator performs an operation of directly pushing the upper surface of the operation portion 221 with a finger. FIG. 10 is a side cross-sectional view showing a state where the operator performs an operation of directly pushing the upper surface of the action section 221 in the force detector shown in FIG. 9. Thin flexible part 22
2 is a state where the cross section is bent in an inverted V-shape. In the state shown in FIG. 9, when the downward pressing force on the action portion 221 is gradually increased, the flexible portion 22
2 suddenly bends in an inverted V-shape, causing elastic deformation, and FIG.
The state shown in FIG. For this reason, the click feeling is transmitted to the operator's finger, and it is possible to reliably recognize by touch that the operation input has been performed.

(2) Modified Example of Pressing Individual Indices Positions The modified example shown in the side sectional view of FIG. 11 is basically the same as the embodiment shown in FIG. That is, the displacement generator 320 is disposed on the substrate 310 and the displacement generator 32
0 is 3 of the action portion 321, the flexible portion 322, and the fixed portion 323.
Has two parts. Further, six resistors R1 to R6 are arranged on the upper surface of the substrate 310, and five contact conductors C1 to C5 are arranged on the lower surface of the action portion 321. However, the fixing member as in the embodiment of FIG. 1 is not provided, and the bottom surface of the fixing portion 323 is directly joined to a peripheral portion of the upper surface of the substrate 310. FIG. 12 is a top view of the displacement generator 320. The action portion 321 has a disk shape, and a thin flexible portion 322 is formed by a circumferential groove G dug around the action portion 321. The fixing portion 323 is
Is the outer part. Also, the contact conductors C1 to C5
Are completely separated from the resistors R1 to R5.

In the case of the modification shown in FIG. 11, no operation rod or the like is provided on the upper surface of the action portion 321. The operator performs an operation of directly pushing the upper surface of the action section 321 with a finger. However, in the case of the modification described here, as shown in the top view of FIG. 12, a plurality of indices M1 to M5 are arranged on the upper surface of the disc-shaped acting portion 321. That is, the indices M1 to M4 are triangular indices indicating the right, left, up, and down directions of the figure, respectively.
5 is a square index indicating the center position. These indices may be formed by embossing on the upper surface of the action section 321 or may be formed by printing.

Providing such indices is convenient for performing an operation input slightly different from that of a force detector having an operation rod like the force detector shown in FIG. That is, in the force detector shown in FIG. 1, the operator gives an operation input for moving the operation stick 125 in various directions. In the case of the modification described here, the operator makes five operations shown in FIG. An operation input can be given by applying a pressing force to any of the index positions. For example, when an operation input such as pushing the position of the index M1 in FIG. 12 with a finger is performed, in the side sectional view in FIG. 11, the disc-shaped acting portion 321 is inclined downward and to the right, and the first contact is made. The conductor for use C1 comes into contact with the first resistor R1. This state is equivalent to the case where a force in the + X-axis direction component acts on the force detector according to the above-described embodiment. Similarly, an operation input such as pressing the positions of the indices M2, M3, M4, and M5 in FIG. 12 with a finger is performed by the force detector according to the above-described embodiment.
Equivalent to the case where the force of the component in the -X axis direction acts, the case where the force of the component in the direction of + Y axis acts, the case where the force of the component in the direction of -Y axis acts, and the case where the force of the component in the direction of -Z axis acts. It is.

Eventually, if a force sensor is constructed by adding a detection circuit as shown in FIG. 8 to the force detector according to the modification shown in FIGS. 11 and 12, It becomes possible to detect how much pressing force is applied to the index position. Of course, also in the modification shown in FIGS.
A plurality of indices can be provided on the upper surface of one and can function as a force sensor for detecting the pressing force applied to each of the indices. As described above, the force detector or the force sensor according to the present invention not only detects an external force acting in a specific coordinate axis direction, but also detects a pressing force that causes a displacement equivalent to such an external force to the acting portion. It is also possible to do. As shown in the embodiment of FIG. 1, the input device for the computer game is not only a joystick type having an operation stick 125, but also an input device shown in FIGS.
As in the modification shown in FIG.
The type 1) of pressing the upper, lower, left and right or the center is also used, and the force detector according to the present invention can be applied to any type.

(3) Modifications Regarding Shape of Contact Conductor In the embodiments described above, the contact conductors C1 to C5
Were bowl-shaped, but the contact conductors were
Any material may be used as long as it is made of an elastically deformable conductive material and has a shape in which the area of the contact surface changes based on a change in the contact state with the resistor (change in contact pressure). Absent. In the case of a contact conductor having a bowl shape, the contact surface is substantially circular, and as the contact pressure increases, the contact surface becomes a circle having a larger diameter, but the contact surface does not necessarily have to be circular.

FIG. 13A shows a wedge-shaped contact conductor C.
FIG. 13B is a perspective view showing a state in which the resistor R is in contact with the upper surface of the resistor R. FIG. It is a sectional side view which shows the contact state with the contact conductor C. When a downward pressing force is applied to the contact conductor C, the contact area increases according to the magnitude of the pressing force. FIG. 13C is a top view of the resistor R, showing the contact surface S when a predetermined pressing force is applied. Terminal T
1 and T2 are terminals for measuring the resistance value of the resistor R. The contact surface S has a rectangular shape as shown. Here, a vertical line in the rectangular contact surface S indicates an isobar in the contact surface.

An advantage of using the wedge-shaped contact conductor C is that the effective contact area does not change even if the contact position with respect to the resistor R changes. For example, in the case of the modification shown in FIG. 9, since the flexible portion 222 is considerably long, when the action portion 221 is displaced downward in the figure, as shown in FIG. , There is a possibility that the contact position of the contact conductor C with respect to the resistor R is largely shifted. At this time, in the case of the bowl-shaped contact conductor C, the effective contact area may be changed because the contact surface is circular. For example, in the example shown in FIG. 6B, since the contact position is the center position of the resistor R, the contact surface S is within the outline of the resistor R, but when the contact position is shifted, Part of the contact surface S is a resistor R
, And the effective contact area is reduced from the original one. As described above, when the effective contact area changes due to the change in the contact position, a correct detection value cannot be obtained.

As shown in FIG. 13A, the width d of the resistor R is
When a wedge-shaped contact conductor C having a sufficient width dc with respect to r is used, as shown in FIG. 13C, the contact surface S at the time of contact with the same pressing force becomes Will always be the same size rectangle. Therefore, even if the contact position is shifted, the shift in the vertical direction in FIG. 13C is within the margin of the width dc, and the shift in the horizontal direction is
No change occurs in the effective contact area as long as it is within the range of the width in the lateral direction.

(4) Modification of Wiring on Board In order to configure a force sensor using the force detector according to the present invention, a detection circuit as shown in FIG. It is necessary to perform wiring for forming. Such a wiring can be formed by printing a conductive layer on a substrate. If necessary, it is also possible to form a through hole at a predetermined position on the substrate, and to provide wiring on the lower surface side of the substrate through the through hole.

FIG. 14 is a top view showing an example of wiring for a resistor formed on a substrate 410. FIG. The substrate 410 shown here is a substrate used for a two-dimensional force detector for detecting the components of the force in the X-axis and Y-axis directions, so that only four resistors R1 to R4 are formed. Each of the four resistors R1 to R4 is a plate-shaped resistor having the same rectangular shape, and electrode portions (portions indicated by thick black lines) E11 to E42 are formed at both ends thereof. Each electrode part E11
Wirings W11 to W42 are connected to.
These wirings W11 to W42 are connected to terminals T11 to T42 provided near the outer periphery of the substrate 410. By further providing external wiring to these terminals T11 to T42, a detection circuit as shown in FIG. 8 can be configured.

When a plurality of resistors are arranged on the upper surface of the substrate, it is practically preferable to arrange them in consideration of such convenience of wiring. For example, as shown in the plan view of FIG. 15, four sets of rectangular resistors R having a short side length L and a long side length 2L are arranged on a substrate. Consider a case where a substrate used for a two-dimensional force detector is configured. In this case, for example, various arrangements as shown in FIGS. 16 (a), (b) and (c) are possible. In each case, four resistors R1 to R4 are arranged so as to surround the origin O defined in the center of the substrate. Here, assuming that the distance between the center position (shown by a black dot in the figure) of each resistor and the origin O is K, in the arrangement shown in FIG. , (C), K = L +
(L / 2). Therefore, in terms of spatial arrangement efficiency, the arrangement shown in FIG. 16A is optimal, and the size of the force detector can be reduced. However, in wiring, a through hole is formed in the substrate. It is necessary to take a method such as wiring on the lower surface side of the substrate.

(5) Application to Acceleration Detection In each of the examples described so far, a force detector or a force sensor for detecting an external force applied to the operation rod or the acting portion has been described. If a force sensor is used, an acceleration detector or an acceleration sensor can be realized. That is, if a weight having a mass corresponding to the required acceleration detection sensitivity is joined to the acting portion, and an external force acts on the acting portion based on the acceleration acting on the weight,
By detecting the applied external force, the applied acceleration can be detected.

The detector shown in the sectional side view of FIG. 17 is an acceleration detector constructed by adding a weight to the force detector shown in FIG. 1. Basically, the force detector shown in FIG. It has almost the same components as the detector. That is, the substrate 5
Displacement generator 520 is arranged on 10, and both are fixed by fixing member 530 at the periphery thereof. The same applies to the point that the displacement generator 520 has three parts of an action part 521, a flexible part 522, and a fixed part 523.
The same applies to the point that six resistors R1 to R6 are arranged on the upper surface of 10 and the five contact conductors C1 to C5 are arranged on the lower surface of the action part 521. However, a weight body 540 is joined to the upper surface of the action portion 521 via an intermediate member 525.

By adding a detection circuit as shown in FIG. 8 to such an acceleration detector, an acceleration sensor can be constructed. That is, if the substrate 510 or the fixing member 530 of the acceleration detector shown in FIG. 17 is fixed to a vehicle or the like, and the weight 540 can be freely displaced (in practice, the case around the weight 540 is a case). To prevent the weight body 540 from contacting other objects), the acceleration applied to the vehicle is also applied to the weight body 540, and the force corresponding to the acceleration is applied via the intermediate member 525. This is transmitted to the action section 521. The principle of detecting such a component in the direction of each coordinate axis of the force is as described above. Since the force detected in this manner is an amount proportional to the applied acceleration, the acceleration can be indirectly detected.

[0079]

As described above, according to the present invention, it is possible to realize a force detector and a force sensor capable of detecting the magnitude of an applied force while having a simple structure and a low manufacturing cost. become able to.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing a structure of a force detector according to a basic embodiment of the present invention.

FIG. 2 is a top view of a substrate 110 in the force detector shown in FIG. 1, and a cross section of the substrate 110 taken along the X axis is shown in FIG.

FIG. 3 shows a displacement generator 120 in the force detector shown in FIG.
FIG. 1 is a top view, and FIG. 1 shows a cross section of the displacement generator 120 cut along the X axis.

FIG. 4 shows a displacement generator 120 in the force detector shown in FIG.
FIG. 1 is a bottom view, and FIG. 1 shows a cross section of the displacement generator 120 taken along the X-axis.

FIG. 5 is a side sectional view (a), a plan view (b), and an equivalent circuit diagram (c) showing a contact state between the resistor R and the contact conductor C when no external force is applied.

FIG. 6 is a side sectional view (a) and a plan view showing a contact state between a resistor R and a contact conductor C in a state where an external force is applied.
(b) is an equivalent circuit diagram (c).

FIG. 7 shows a force detector shown in FIG.
FIG. 4 is a side sectional view showing a state when a function is performed.

FIG. 8 is a circuit diagram showing an example of a detection circuit used for the force detector shown in FIG.

FIG. 9 is a side sectional view showing a structure of a force detector according to a first modification of the present invention.

FIG. 10 is a side sectional view showing a state where an external force acts on the force detector shown in FIG. 9;

FIG. 11 is a side sectional view showing a structure of a force detector according to a second modification of the present invention.

FIG. 12 is a top view of the detector shown in FIG. 11;

FIG. 13 is a perspective view (a), a side sectional view (b), and a plan view (c) showing a contact state between a wedge-shaped contact conductor C and a resistor R used in a modification of the present invention.

FIG. 14 is a top view showing an example of wiring for a resistor formed on a substrate 410.

FIG. 15 is a plan view showing an example of a resistor R having a rectangular shape.

16 is a plan view showing a variation of the arrangement of the resistor R having a rectangular shape shown in FIG.

FIG. 17 is a side sectional view of an acceleration detector using a force detector according to the present invention.

[Explanation of symbols]

 110 ... Substrate 120 ... Displacement generator 121 ... Working part 122 ... Flexible part 123 ... Fixed part 125 ... Operation rod 130 ... Fixed member 210 ... Substrate 220 ... Displacement generator 221 ... Working part 222 ... Flexible part 223 ... Fixed part 230 ... fixed member 310 ... substrate 320 ... displacement generator 321 ... operating part 322 ... flexible part 323 ... fixed part 410 ... substrate 510 ... substrate 520 ... displacement generator 521 ... operating part 522 ... flexible part 523 ... fixed part 525 ... Intermediate member 530... Fixing member 540... Weight body C, C1 to C5... ... + X-axis component of external force -Fz -Z-axis component of external force G ... Circumferential groove Jx, Jy, Jz ... Connection points M1 to M5 ... Index O ... Origin of coordinate system R, R1 to R6 Resistor S: Contact surface T1, T2, T11 to T42: Terminal Tx, Ty, Tz: Output terminal of detected value V: Cavity Vcc: Power supply voltage W11 to W42: Wiring X, Y, Z: Three-dimensional coordinate system Each coordinate axis

Claims (19)

[Claims] 1. A force detector for detecting an external force acting in the X-axis direction or a pressing force equivalent to the external force in an XYZ three-dimensional coordinate system, comprising: a substrate having an upper surface along an XY plane in the coordinate system; A displacement generator having an action portion disposed above the substrate, a fixed portion fixed to the substrate, and a flexible portion formed between the action portion and the fixed portion; When an origin of the coordinate system is defined substantially at the center of the upper surface of the substrate, a first resistor and a second resistor respectively disposed in the X-axis positive region and the X-axis negative region of the substrate upper surface. A first contact conductor and a second contact conductor arranged at positions on the lower surface of the action section facing the first resistor and the second resistor, respectively; When an external force acts on the acting portion, the flexible portion bends. The displacement causes the lower surface of the working portion to be displaced relative to the upper surface of the substrate.
And the contact state of the contact conductor and the second contact conductor with respect to the first resistor and the second resistor is changed, and the first contact conductor and the second The contact conductor 2 is made of a conductive material that is elastically deformed, and the area of the contact surface changes based on a change in the state of contact with the first resistor and the second resistor. It has a shape, and based on the change in the area of the contact surface, it is possible to detect an external force acting on the acting portion in the X-axis direction or a pressing force that causes the acting portion to generate a displacement equivalent to the external force. A force detector characterized in that: 2. A force sensor constituted by adding a predetermined detection circuit to the force detector according to claim 1, wherein the first contact conductor is provided on a first resistor. By comparing a resistance value between two points sandwiching the “contact position” with a resistance value between two points sandwiching the “contact position of the second contact conductor” on the second resistor, the X-axis is obtained. A force sensor, wherein a circuit for detecting an external force acting in a direction or a pressing force equivalent to the external force is added as the predetermined detection circuit. 3. The force sensor according to claim 2, wherein the first resistor and the second resistor are connected in series at an X-axis detection connection point to form an X-axis detection resistor. A predetermined voltage is applied to both ends of the X-axis detection resistor, and a value corresponding to the voltage at the X-axis detection connection point is defined as an external force applied in the X-axis direction or a value of a pressing force equivalent to the external force. A force sensor using a detection circuit for outputting. 4. The force detector according to claim 1, wherein a third resistor and a fourth resistor are respectively disposed in a Y-axis positive region and a Y-axis negative region on an upper surface of the substrate; A third contact conductor and a fourth contact conductor arranged at positions on the lower surface facing the third resistor and the fourth resistor, respectively; Changes the contact state of the third contact conductor and the fourth contact conductor with the third resistor and the fourth resistor based on the displacement generated with respect to the upper surface of the substrate. The third contact conductor and the fourth contact conductor are made of a conductive material that is elastically deformed, and the third resistor and the fourth resistor are The area of the contact surface changes based on the change of the contact state It has a shape,
Based on the change in the area of the contact surface, it is further possible to detect an external force acting on the acting portion in the Y-axis direction or a pressing force that causes a displacement equivalent to the external force to the acting portion. Characteristic force detector. 5. A force sensor constituted by adding a predetermined detection circuit to the force detector according to claim 4, wherein the first contact conductor is provided on a first resistor. By comparing a resistance value between two points sandwiching the “contact position” with a resistance value between two points sandwiching the “contact position of the second contact conductor” on the second resistor, the X-axis is obtained. A circuit for detecting an external force acting in the direction or a pressing force equivalent to the external force; a resistance value between two points sandwiching the “contact position of the third contact conductor” on the third resistor; The external force acting in the Y-axis direction or a pressing force equivalent to the external force is detected by comparing the resistance value between two points sandwiching the “contact position of the fourth contact conductor” on the resistor. A force sensor, wherein a circuit having the following is added as the predetermined detection circuit. 6. The force sensor according to claim 5, wherein the first resistor and the second resistor are connected in series at an X-axis detection connection point to form an X-axis detection resistor. A predetermined voltage is applied to both ends of the X-axis detection resistor, and a value corresponding to the voltage at the X-axis detection connection point is output as an external force acting in the X-axis direction or a value of a pressing force equivalent to the external force. A third resistor and a fourth resistor are connected in series at the Y-axis detection connection point to form a Y-axis detection resistor, and a predetermined voltage is applied to both ends of the Y-axis detection resistor. And a detection circuit that outputs a value corresponding to the voltage of the connection point for Y-axis detection as an external force applied in the Y-axis direction or a value of a pressing force equivalent to the external force. 7. The force detector according to claim 1, wherein the Z-axis resistor disposed on the upper surface of the substrate and the Z-axis resistor disposed on the lower surface of the acting portion at a position facing the Z-axis resistor. And a contact state for the Z-axis contact conductor, the contact state of the Z-axis contact conductor changing with the Z-axis resistor, based on a displacement of the lower surface of the operating portion with respect to the upper surface of the substrate. And the Z
The shaft contact conductor is made of an elastically deformable conductive material, and has a shape in which the area of the contact surface changes based on a change in the contact state with the Z-axis resistor,
Based on the change in the area of the contact surface, it is possible to further detect an external force acting on the acting portion in the Z-axis direction or a pressing force that causes a displacement equivalent to the external force to the acting portion. Characteristic force detector. 8. The force detector according to claim 7, wherein the Z-axis resistor and the Z-axis contact conductor are arranged at positions intersecting with the Z-axis. 9. The force detector according to claim 7, wherein a reference resistor whose constant value between two predetermined points is constant without being affected by an external force or a pressing force is provided on an upper surface of the substrate. A force detector further provided. 10. A force sensor constituted by adding a predetermined detection circuit to the force detector according to claim 9, wherein the first contact conductor is provided on a first resistor. By comparing a resistance value between two points sandwiching the “contact position” with a resistance value between two points sandwiching the “contact position of the second contact conductor” on the second resistor, the X-axis is obtained. A circuit for detecting an external force acting in the direction or a pressing force equivalent to the external force; a resistance value between two points sandwiching the “contact position of the Z-axis contact conductor” on the Z-axis resistor; By comparing the resistance value between two points at which the resistance value is "constant without being affected by external force or pressing force" on the resistor, the external force applied in the Z-axis direction or the same pressing force as the external force is applied. A circuit for detecting pressure; and a circuit having: Sensor. 11. The force sensor according to claim 10, wherein the first resistor and the second resistor are connected in series at an X-axis detection connection point to form an X-axis detection resistor. A predetermined voltage is applied to both ends of the X-axis detection resistor, and a value corresponding to the voltage at the X-axis detection connection point is output as an external force acting in the X-axis direction or a value of a pressing force equivalent to the external force. The Z-axis resistor and the reference resistor are connected in series at the Z-axis detection connection point to form a Z-axis detection resistor, and a predetermined voltage is applied to both ends of the Z-axis detection resistor. A force sensor, comprising: a detection circuit for applying and outputting a value corresponding to the voltage at the Z-axis detection connection point as an external force acting in the Z-axis direction or a value of a pressing force equivalent to the external force. 12. The force detector according to claim 4, wherein the Z-axis resistor disposed on the upper surface of the substrate and the Z-axis disposed on the lower surface of the acting portion at a position facing the Z-axis resistor. And a contact state for the Z-axis contact conductor, the contact state of the Z-axis contact conductor changing with the Z-axis resistor, based on a displacement of the lower surface of the operating portion with respect to the upper surface of the substrate. And the Z
The shaft contact conductor is made of an elastically deformable conductive material, and has a shape in which the area of the contact surface changes based on a change in the contact state with the Z-axis resistor,
A force detector characterized in that an external force acting in the Z-axis direction or a pressing force equivalent to the external force can be detected based on the change in the area of the contact surface. 13. The force detector according to claim 12, wherein the Z-axis resistor and the Z-axis contact conductor are arranged at positions intersecting the Z-axis. 14. The force detector according to claim 12, wherein a reference resistor whose resistance value between two predetermined points is constant without being affected by an external force or a pressing force is provided on an upper surface of the substrate. A force detector further provided. 15. A force sensor constituted by adding a predetermined detection circuit to the force detector according to claim 14, wherein the first contact conductor is provided on the first resistor. By comparing a resistance value between two points sandwiching the “contact position” with a resistance value between two points sandwiching the “contact position of the second contact conductor” on the second resistor, the X-axis is obtained. A circuit for detecting an external force acting in the direction or a pressing force equivalent to the external force; a resistance value between two points sandwiching the “contact position of the third contact conductor” on the third resistor; The external force acting in the Y-axis direction or a pressing force equivalent to the external force is detected by comparing the resistance value between two points sandwiching the “contact position of the fourth contact conductor” on the resistor. And the resistance between two points sandwiching the “contact position of the Z-axis contact conductor” on the Z-axis resistor, and the reference resistor By comparing the above resistance value between two points at which the resistance value is constant without being affected by an external force or a pressing force, the external force acting in the Z-axis direction or a pressing force equivalent to the external force is calculated. A force sensor, wherein a circuit having: a detection circuit; and a circuit having: 16. The force sensor according to claim 15, wherein the first resistor and the second resistor are connected in series at an X-axis detection connection point to form an X-axis detection resistor. A predetermined voltage is applied to both ends of the X-axis detection resistor, and a value corresponding to the voltage at the X-axis detection connection point is output as an external force acting in the X-axis direction or a value of a pressing force equivalent to the external force. A third resistor and a fourth resistor are connected in series at the Y-axis detection connection point to form a Y-axis detection resistor, and a predetermined voltage is applied to both ends of the Y-axis detection resistor. And outputs a value corresponding to the voltage of the Y-axis detection connection point as an external force acting in the Y-axis direction or a value of a pressing force equivalent to the external force. The Z-axis resistor and the reference resistor Are connected in series at a connection point for Z-axis detection, thereby forming a resistor for Z-axis detection. A predetermined voltage is applied to both ends of the Z-axis detection resistor, and a value corresponding to the voltage of the Z-axis detection connection point is applied to an external force applied in the Z-axis direction or a pressing force equivalent to the external force. A force sensor using a detection circuit that outputs a value. 17. The force detector or force sensor according to claim 1, wherein an operation rod is provided on an upper surface of the operation portion, and the lower surface of the operation portion is moved by an external force applied through the operation rod. A force detector or a force sensor configured to generate a displacement with respect to an upper surface of a substrate, and capable of detecting an external force applied to the operation rod. 18. The force detector or force sensor according to claim 1, wherein a plurality of indices are arranged on an upper surface of the acting portion, and the force is actuated by a pressing force applied to each index position. A force detector or a force sensor, wherein a lower surface of the portion is displaced with respect to an upper surface of the substrate to detect how much pressing force is applied to which index position. 19. An acceleration detector or an acceleration sensor using the force detector or the force sensor according to claim 1, wherein a weight is joined to the action portion, and the weight is attached to the weight. An external force acts on the acting portion based on the acted acceleration,
An acceleration detector or an acceleration sensor, wherein an applied acceleration can be detected by detecting an applied external force.