JP3448741B2 - Force detection device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a force detecting device.

[0002]

2. Description of the Related Art For example, Japanese Patent Publication No.
There is one disclosed in Japanese Patent Publication No. 49029-490.

As shown in FIG. 10, this force detecting device has a P
Form a semi-conductive layer and a conductor pattern on the ET film,
It is assumed that the pressure distribution and magnitude are measured by the contact resistance between the conductor pattern C and each conductor pattern N, S, E, W.

However, in the above force detection device, a special semiconductive layer must be printed on the PET film, and a connector, an anisotropic conductive tape or the like is required for connecting the conductor pattern and the circuit board. Therefore, there is a problem that the cost is high and the mounting is difficult.

Therefore, in the industry that deals with this type of force detecting device, it is desired to develop a force detecting device that is low in cost and easy to mount.

[0006]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a force detecting device which is low in cost and easy to mount.

[0007]

According to a first aspect of the present invention, there is provided a force detecting device comprising: a substrate having at least two force detecting conductive lands and a common conductive land provided therebetween; An elastic plate made of a conductive rubber or a conductive elastomer, which is arranged to face the force detecting conductive land and the common conductive land, and a large number of minute protrusions formed on the surface of the elastic plate facing the force detecting conductive land. A contact resistance generating surface and a flat conductive elastic contact formed on a surface of the elastic plate facing the common conductive land are provided. When the elastic plate is pushed in, the elastic plate causes the force detecting conductive land and the common conductive land. While contacting the land, the small protrusions on the contact resistance generation surface are crushed according to the magnitude and direction of the force, and as a result, the contact area between the contact resistance generation surface and the conductive land for force detection increases The resistance between the conductive land and the common conductive land is reduced. (Invention of Claim 2) The force detection device of the present invention comprises a substrate having at least two conductive lands for detecting force and a common conductive land provided between them, and a non-conductive rubber or non-conductive elastomer. The force detection conductive film is provided with a contact resistance generating surface composed of a large number of minute projections and an elastic plate having a flat conductive elastic contact formed by adhering conductive ink, pressure-sensitive resistance ink or conductive paint. The land and the contact resistance generation surface,
The substrate and the elastic plate are arranged to face each other in such a manner that the common conductive land and the conductive elastic contact face each other, and when the elastic plate is pushed in, the elastic plate comes into contact with the force detection conductive land and the common conductive land. The small protrusions on the contact resistance generation surface are crushed according to the magnitude and direction of the force, and as a result, the contact area between the contact resistance generation surface and the conductive land for force detection increases, and the conductive land for force detection and common conductivity Resistance between lands becomes smaller. (Invention of Claim 3) The force detection device of the present invention relates to the invention of Claim 1 or 2, wherein four force detection conductive lands are arranged at 90 ° intervals.
The common conductive land is arranged on the orthogonal X-axis and Y-axis so that the magnitude and direction of the force in the X-axis and Y-axis directions can be detected. (Invention of Claim 4) The force detection device of this invention relates to the invention of Claim 1 or 2, wherein the force detection conductive lands are arranged in an arbitrary number around a common conductive land in an arbitrary direction. The magnitude and direction of the force corresponding to the number of the conductive lands for force detection can be detected. (Invention of Claim 5) The force detection device of the present invention relates to the invention of any one of claims 1 to 4, wherein the force detection conductive land and the contact resistance generating surface are the common conductive land and the conductive elastic contact. Are arranged with a gap therebetween. (Invention of Claim 6) The force detection device of this invention relates to the invention of any one of Claims 1 to 4, wherein a switch contact conductive land is provided on a portion of the substrate facing the conductive elastic contact. is there.

The function of the force detection device of the above invention will be clarified in the section of the following embodiments of the invention.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below with reference to the drawings shown as embodiments. [Embodiment 1] FIG. 1 is a sectional view of a force detection device S according to an embodiment of the present invention, and FIG. 2 is a force detection conductive land Dx +, Dx- on a substrate 1 constituting the force detection device S. ，
Dy +, Dy-, the common conductive land DS1 and the switch contact conductive land DS2 are shown, and FIG. 3 shows the contact resistance generating surface 30 and the conductive elastic contact 31 formed on the elastic plate 3.

This force detecting device S, as shown in FIG.
Substrate 1 and operation buttons 2 arranged to face the substrate 1
And an elastic plate 3 fixed to the lower surface of the operation button 2,
It is composed of a support tool 4 for fixing the operation part 2 on the substrate 1 and a cap 5 for covering the operation button 2.

As shown in FIG. 1, the substrate 1 is composed of a thin printed circuit board, and as shown in FIG. 2, the upper surface is divided into four circular conductive lands Dx +, Dx for detecting force.
-, Dy +, Dy- are arranged equidistantly from the origin O on the XY axis, and a circle surrounded by the force detection conductive lands Dx +, Dx-, Dy +, Dy- with the origin O as the center. An annular common conductive land DS1 is arranged, and further, a switch contact conductive land DS2 is arranged at an origin O portion surrounded by the common conductive land DS1. Each of the lands described above has a copper layer formed on the substrate 1 with a solder layer, gold plated or silver plated, carbon printed, solder welded, or conductive. It is made of pressed metal. Further, the force detecting conductive lands Dx +, Dx−, Dy +, Dy−, the common conductive land DS1 and the switch contact conductive land DS2 are electrically insulated from each other, and are drawn out to appropriate positions on the substrate 1 by terminals. ing.

As shown in FIG. 1 and FIG. 3, the operation button 2 is composed of a button portion 20, which is made of non-conductive rubber or non-conductive elastomer, a mounting portion 21 and a deformable portion 22, which are It is integrally molded.

As shown in FIG. 1, the button portion 20 is formed of a thick circular plate having the same diameter as the circle formed by the outer peripheral lines of the force detecting conductive lands Dx +, Dx−, Dy +, Dy−.

The mounting portion 21, as shown in FIG. 1, is a button portion.
It is composed of a thick annular plate having a diameter larger than 20.

As shown in FIG. 1, the deforming portion 22 has a thin cone shape and connects the outer peripheral surface of the button portion 20 and the upper end of the inner peripheral surface of the mounting portion 21.

As shown in FIGS. 1 and 3, the elastic plate 3 is formed of a thick circular plate having the same diameter as the button portion 20, and is entirely made of conductive rubber or conductive elastomer. . Further, in the elastic plate 3, as shown in FIGS. 1 and 3, the force detecting conductive lands Dx +, Dx−, Dy +, Dy.
The surface facing − is a contact resistance generating surface 30 having a large number of minute protrusions t (for example, satin finish), and the surface facing the common conductive land DS1 and the switch contact conductive land DS2 is more than the contact resistance generating surface 30. Is a flat conductive elastic contact 31 protruding by a distance a. The conductive rubber used for the elastic plate 3 is generally available 0.1
It has a volume resistance value of about 100 Ω · cm.

As shown in FIG. 1, the supporting member 4 has an inverted L-shaped cross section.
It is a ring-shaped one that is formed in a letter shape.
I try to hold down the upper surface of.

As shown in FIG. 1, the cap 5 is made of a hard resin circular plate and is fixed to the upper surface of the operation button 2. The cap 5 is provided in this way so that the pushing force by the finger effectively acts on the elastic plate 3.

Since the force detecting device S of the embodiment of the present invention has the above-mentioned configuration, it functions as follows. When the operation button 2 is pushed into the substrate 1 side from directly above or obliquely via the cap 5, a light operation feeling (click feeling) that the deformed portion 22 is buckled is transmitted to the operating finger. Then, the conductive elastic contacts 31 of the elastic plate 3 come into contact with the common conductive land DS1 while deforming, so that the entire elastic plate 3 made of conductive rubber or the like has substantially the same potential as the common conductive land DS1. As shown in FIG. 4, when the operation button 2 is pushed with a finger so that the conductive elastic contact 31 comes into full contact with the common conductive land DS1, it is inevitably contacted with the switch contact conductive land DS2. Since the surface of the conductive elastic contact 31 is flat as described above, almost no contact resistance is generated between the common conductive land DS1 and the switch contact conductive land DS2, and both are brought into conduction. That is, the common conductive land DS1 and the switch contact conductive land DS2 are "closed" as a switch. As shown in FIG. 5, when the operation button 2 is strongly pushed into the force detecting conductive land Dx +, the elastic plate 3 contacts the common conductive land DS1 and the force detecting conductive land Dx +.

Since the contact resistance generating surface 30 of the elastic plate 3 is provided with the minute protrusion t, it prevents the elastic plate 3 from closely contacting the force detecting conductive land Dx +, resulting in innumerable point contacts. It has a certain degree of contact resistance Rx +. Further, when the force of pushing the operation button 2 is increased, the tip of the minute protrusion t is crushed and the contact area with the force detection conductive land Dx + increases, so the contact resistance Rx + depends on the magnitude of the force. Get smaller. Other force detection conductive lands Dx-, D
The same applies to y + and Dy-.

Depending on the strength of the pushing of the operation button 2, the minute projection t of the elastic plate 3 may come into contact with the force detecting conductive lands Dx−, Dy +, Dy− and be crushed. The relationship of contact area is (contact resistance generation surface
Contact area between 30 and force detection conductive land Dx +)> [(contact area between contact resistance generation surface 30 and force detection conductive land Dy +) = (contact resistance generation surface 30 and force detection conductive land Dy-
Contact area)> (contact area between the contact resistance generating surface 30 and the force detecting conductive land Dx−). Therefore, (contact resistance Rx +) <[(contact resistance Ry +) = (contact resistance Ry
−)] <(Contact resistance Rx−) holds. A circuit diagram of the above is shown in FIG.

In FIG. 6, Tx +, Tx-, Ty +, Ty-.
Is a terminal drawn out from the force detecting conductive lands Dx-, Dy +, Dy- to an appropriate position, and TS1 is a common conductive land.
The terminal is drawn from DS1 to a proper position, and TS2 is the terminal drawn from switch contact conductive land DS2 to a proper position. In this force detection device S, if the operation button 2 is pushed in with an extreme inclination, the elastic portion 3 does not come into contact with the common conductive land DS1 and the force detection conductive lands Dx−, Dy +, Dy.
Operation button 2 may be touched
If the inclination of is corrected, it can be easily brought into contact with the common conductive land DS1. If a circuit as shown in FIG. 7 is configured using this force detection device S, it is possible to output a voltage according to the magnitude and direction of the force with which the operation button 2 is pressed, and the operation button 2
It can also output a switch signal that can be used to confirm that the button has been pushed.

The operation button 2 is set to the conductive land Dx + for force detection.
When pushed in, the conductive elastic contacts 31 of the elastic plate 3 come into contact with the common conductive land DS1 and the force detecting conductive land Dx + becomes GN.
It becomes the D potential. At this time, since the contact resistance Rx + is the smallest, Vx + is the smallest. However, if (Vx +) − (Vx−) is calculated using an appropriate method, the magnitude and direction of the force pushing the operation button 2 in the X-axis direction To (Vy +)-
By calculating (Vy−), the magnitude and direction of the force pushing the operation button 2 in the Y-axis direction can be detected.

The output of the switch signal composed of the common conductive land DS1 and the switch contact conductive land DS2 may be used depending on the application.

In the circuit of FIG. 7, when the operation button 2 is not pushed, no current flows, so that the power consumption can be made "0". From the above, by using the present invention, it is possible to inexpensively provide a joystick for a pointing device of a game machine or a personal computer that can reduce the current consumption when not operating. [Second Embodiment] FIG. 8 is a sectional view of a force detection device S according to a second embodiment of the present invention.

In this force detecting device S, as shown in FIG. 8, the elastic plate 3 is provided without providing the conductive land DS2 for switch contact.
The conductive elastic contact 31 of is always connected to the common conductive land DS1. Even in this case, if the circuit of FIG. 7 is configured, the magnitude and direction of the force in the X-axis and Y-axis directions can be detected as in the case of the first embodiment. [Other Embodiments] The force detection device S according to the first and second embodiments.
The elastic plate 3 having the contact resistance generating surface 30 and the conductive elastic contact 31 is made of conductive rubber or conductive elastomer, but is not limited to this. For example,
As shown in FIG. 9, a contact resistance generating surface 30 composed of a large number of minute projections t formed by adhering conductive ink 32, pressure-sensitive resistance ink or conductive paint to non-conductive rubber or non-conductive elastomer, and The elastic plate 3 having the flat conductive elastic contact 31 may be used.

In the force detecting device S of the first and second embodiments,
Four force detection conductive lands Dx +, Dx-, Dy +, D
Although y− is provided, the present invention is not limited to this, and the force detection conductive lands may be Dx +, Dx− or Dy +,
Two of Dy− may be used, or Dx + and Dy + may be used. Further, eight force detecting conductive lands may be arranged at equal angular intervals. In short, it suffices to arrange the force detecting conductive lands according to the direction of the force to be detected.

The shape of the force detecting conductive land is not limited to the fan shape, and may be a polygon such as a triangle or a quadrangle, or a circle or an ellipse.

The shape of the operation button 2 in plan view is not limited to a circle, but may be a quadrangle or the like. [Advantages of Force Detection Device S of the Above Embodiment] The force detection device S basically has a substrate 1 on which conductive lands for force detection and common conductive lands are formed, operation buttons 2, and an elastic plate 3. And the support tool 4. Moreover, it is possible to reduce the number of parts by integrating other switches and members.
Therefore, it is much cheaper than the conventional one, in which a special semi-conductive layer must be printed on the PET film and a connector or an anisotropic conductive tape is required for connecting the conductor pattern and the circuit board. It is easy to implement.

[0030]

The present invention having the above-mentioned structure has the following effects.

As is clear from the description of the section of the embodiment of the invention, it is possible to provide a force detecting device which is low in cost and easy to mount.

[Brief description of drawings]

FIG. 1 is a sectional view of a force detection device according to a first embodiment of the present invention.

FIG. 2 is a plan view of conductive lands and the like formed on a substrate that constitutes the force detection device.

FIG. 3 is an explanatory diagram of an elastic plate that constitutes the force detection device.

FIG. 4 is a cross-sectional view when a force is applied so that a button portion of the force detection device does not tilt.

FIG. 5 is a cross-sectional view when a force is applied so that a button portion of the force detection device tilts.

FIG. 6 is a diagram in which contact resistance and the like between a force detection conductive land and a contact resistance generation surface are expressed in an electric circuit.

FIG. 7 is a diagram of an application circuit that can be used in this embodiment.

FIG. 8 is a sectional view of a force detection device according to a second embodiment of the present invention.

FIG. 9 is a cross-sectional view of an elastic plate of another embodiment.

FIG. 10 is an explanatory diagram of prior art.

[Explanation of symbols]

S force detector Dx + conductive land Dx- Conductive land Dy + conductive land Dy- Conductive land DS1 Common conductive land Conductive land for DS2 switch contact t Small protrusion 1 substrate 2 operation buttons 3 elastic plate 4 Supports 5 caps 20 Button part 21 Deformation part 22 Mounting part 30 Contact resistance generation surface 31 Conductive elastic contact

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G01L 1/00 H01H 13/64

Claims (6)

(57) [Claims] 1. A substrate having at least two force-detecting conductive lands and a common conductive land provided between them, and a conductive rubber or a conductive member arranged to face the force-detecting conductive lands and the common conductive lands. An elastic plate made of an elastomer, a contact resistance generating surface having a large number of minute projections formed on a surface of the elastic plate facing the force detecting conductive land, and a surface of the elastic plate facing the common conductive land. And a flat conductive elastic contact, and when the elastic plate is pushed in, the elastic plate comes into contact with the force detecting conductive land and the common conductive land, and the minute protrusions on the contact resistance generating surface according to the magnitude and direction of the force. Is crushed, and accordingly, the contact area between the contact resistance generating surface and the force detection conductive land is increased, and the resistance between the force detection conductive land and the common conductive land is reduced. Force detection device. 2. A substrate having at least two conductive lands for detecting force and a common conductive land provided therebetween, and a conductive ink, a pressure-sensitive resistance ink, or a conductive material on a non-conductive rubber or a non-conductive elastomer. A contact resistance generating surface composed of a large number of minute projections formed by adhering paint and an elastic plate having a flat conductive elastic contact, and the force detecting conductive land and the contact resistance generating surface are provided as a common conductive land. When the elastic plate is pushed in, the elastic plate comes into contact with the force detection conductive land and the common conductive land and the magnitude of the force is increased. Depending on the direction and direction, the small protrusions on the contact resistance generation surface are crushed, and as a result, the contact area between the contact resistance generation surface and the conductive land for force detection increases, and the conductive run for force detection is increased. The force detecting device is characterized in that the resistance between the terminal and the common conductive land is reduced. 3. The four force detection conductive lands are arranged at 90 ° intervals with the common conductive land centered on the orthogonal X axis and Y axis, and the magnitude and direction of the force in the X axis and Y axis directions are set. The force detection device according to claim 1, wherein the force detection device is capable of detection. 4. The force detecting conductive lands are arranged in an arbitrary number around a common conductive land in an arbitrary direction so that the magnitude and direction of the force corresponding to the number of the force detecting conductive lands can be detected. The force detection device according to claim 1, wherein the force detection device is provided. 5. The force detecting conductive land and the contact resistance generating surface are arranged with a gap between the common conductive land and the conductive elastic contact, respectively.
The force detection device according to any one of 1. 6. The force detecting device according to claim 1, wherein a switch contact conductive land is provided on a portion of the substrate facing the conductive elastic contact.