JPH076853B2 - Directional pressure sensor - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a directional pressure sensor capable of detecting multi-directional pressure applied to, for example, a pen tip of a writing device, and is mainly used for a displacement direction determining device, a handwriting measuring device, etc. The present invention relates to what can be used as a substitute for an input tablet or the like.

[0002]

2. Description of the Related Art Conventionally, a pressure-sensitive conductive rubber having a characteristic that an electric resistance value is lowered due to a compressive deformation caused by a pressing force has been known. This pressure-sensitive conductive rubber is made by mixing and dispersing conductive particles such as metal or carbon black in an insulator such as rubber or elastomer. This pressure-sensitive conductive rubber is in an electrically insulated state because the individual conductive particles are separated from each other when no pressure is applied, but continuously applies pressure to cause compressive deformation. In such a case, the electrical resistance value is continuously reduced by the individual conductive particles coming into contact with each other.

The pressure-sensitive conductive rubber having the above-mentioned characteristics has been put to practical use as a sensor, a switch or the like in various fields or is in the process of trial. As an example, a conductive material forming electrodes is attached to both surfaces in the thickness direction of a pressure-sensitive conductive rubber molded in a flat plate shape or a rectangular parallelepiped shape, and electric resistance change due to compressive deformation is taken out from this electrode. There is a sensor (variable resistor). Further, as a modification of this, for example, Japanese Patent Laid-Open No. 61-61
According to Japanese Patent Laid-Open No. 78101, a pair of electrodes is provided in a non-contact state on one surface of a pressure-sensitive conductive rubber molded to have a uniform thickness (the one shown in the publication is rectangular in cross section), and the pair of electrodes is provided on the other surface. Disclosed is a sensor (variable resistor) configured to provide an electrode extending over the electrodes of (1) and (2) to take out the electric resistance change due to the compressive deformation occurring in the thickness direction from the pair of electrodes. Further, according to Japanese Utility Model Laid-Open No. 53-32366, a pressure-sensitive conductive rubber having a rectangular cross section (a pressure-sensitive resistor in the same publication) is interposed between a support and a pressure member arranged in parallel. A pair of electrode plates insulated from each other is provided between the pressure-sensitive conductive rubber and the support, and the pressure-sensitive conductive rubber is subjected to a compressive deformation when a pressure is applied to the pressure-sensitive conductive rubber. There is disclosed a pressure-sensitive switch configured to take out electric resistance change from the pair of electrodes.

[0004]

However, in any of the above-mentioned conventional examples, the pressure-sensitive conductive rubber having a rectangular cross section (a flat plate shape or a rectangular parallelepiped shape) is compressed by applying a pressure force only in the thickness direction. Since it adopts a method of taking out the electric resistance change from the electrode when deformation occurs,
It has a problem that it can sense only the pressure force in one direction. When pressure is applied to the pressure-sensitive conductive rubber of the conventional example from a direction different from the thickness direction, the electrical resistance value of the pressure-sensitive conductive rubber changes, but from any angle direction. There is a problem that it cannot be used as a sensor for sensing the directionality of the pressing force because it cannot be determined whether the pressing force is acting. Further, each of the above-mentioned conventional examples has a problem in that the entire compression deformation of the pressure-sensitive conductive rubber is detected, and the compression deformation partially generated cannot be accurately detected. Furthermore, in order to discriminate the magnitude and the pressurizing direction of the pressing force from multiple directions using the above-mentioned conventional example, many sensors or switches having the above-mentioned conventional structure must be used, which necessitates the enlargement of the apparatus. It also had the problem of being

The present invention has been made in view of the above-mentioned circumstances, and is applied in what angle direction and in what size with respect to the pressing force applied to the pressure-sensitive conductive elastomer from multiple directions. By providing a direction pressure sensing sensor that can accurately determine whether pressure is acting, it can be actually used for a displacement direction determination device, a handwriting measuring device, etc., which was not available in the past. Therefore, it is a technical subject to significantly expand the usage of the pressure-sensitive conductive elastomer.

[0006]

The directional pressure sensor according to the present invention employs the following concrete means in order to achieve the above technical problems. That is, the first
In the structure having a core rod and a cover member surrounding the periphery of the core rod, the means for pressure-sensitive conductivity is provided between the core rod and the cover member so as to cover the periphery of the core rod. An elastomer is provided, and at least a pair of electrodes is provided at each of a plurality of locations in the circumferential direction of the pressure-sensitive conductive elastomer. The second means is similar to the above in that the pressure-sensitive conductive elastomer is interposed between the core rod and the cover member so as to cover the periphery of the core rod. One electrode is provided at each of a plurality of positions in the circumferential direction of the pressure-sensitive conductive elastomer,
In addition, the core rod is the other common electrode.

[0007]

According to the first means, since the pressure-sensitive conductive elastomer is interposed between the core rod and the cover member so as to cover the core rod, the core is relatively disposed with respect to the cover member. When the rod is displaced in a direction orthogonal to its axial direction, the pressure-sensitive conductive elastomer is partially compressed between the displacement direction portion of the core rod and a portion of the cover member facing the displacement direction portion. Then, since at least a pair of electrodes is disposed at each of the plurality of locations in the circumferential direction of the pressure-sensitive conductive elastomer, the partial compression is performed by the pair of electrodes existing in the vicinity of the location where the partial compression occurs. The electric resistance change due to is taken out. Therefore, the displacement direction of the core rod can be determined by the magnitude of the change in the electrical resistance taken out of the pair of electrodes at a plurality of locations in the circumferential direction of the pressure-sensitive conductive elastomer. In this case, for example, when the electric resistance change is taken out from each pair of electrodes present in two of the plurality of places, the magnitude of the electric resistance value taken out from one pair of electrodes and the other pair of electrodes The displacement direction of the core rod can be accurately determined based on the ratio with the magnitude of the electric resistance value taken out from the electrode. Further, according to the second means, the pressure-sensitive conductive elastomer is provided between the one electrode and the core rod, which is the other common electrode, arranged at a plurality of positions in the circumferential direction of the pressure-sensitive conductive elastomer. The electric resistance change due to the partial compressive deformation of is extracted. Therefore, one of the electrodes existing in a plurality of places,
The displacement direction of the core rod can be determined depending on how much change in electric resistance is extracted from the other electrode, which is the core rod. The cross-sectional shape of the core rod in both of the above means may be not only circular but also triangular, quadrangular or other polygonal shape.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. First, the first embodiment of the directional pressure sensor according to the present invention.
An embodiment will be described with reference to FIGS. As shown in FIG. 1, the first embodiment of the present invention is a writing apparatus or the like in which a core rod 3 is inserted and held in the inner center of a cylindrical body 2 which is a cover member. The pressure-sensitive conductive elastomer molded body 1 is provided between the core rod 3 and the core rod 3 so as to cover the core rod 3. The cylindrical body 2 is formed by screwing a cap 2b onto the tip of a main body 2a, and in the figure, the pressure-sensitive conductive elastomer molding 1 is provided between the cap 2b and the core rod 3. However, the interposition position and the structure of the cylindrical body 2 are not limited to the above. For example, with respect to the tubular body 2, instead of the configuration in which the cap 2b is screwed onto the tip of the main body 2a as described above, the configuration is such that the cap 2b is detachably fitted and fixed to the tip of the main body 2a with one touch. May be

The pressure-sensitive conductive elastomer molding 1 is
As shown in FIG. 2, the core rod 3 is an integrally molded body having an annular cross section covering the entire circumference, and conductive particles such as metal or carbon black are mixed and dispersed in an insulator such as rubber or elastomer. It was made. The core rod 3 is attached to the outer peripheral surface 1a of the pressure-sensitive conductive elastomer molded body 1 by Z
With respect to the axis, a total of four substrates 4 ... 4 having electrodes are attached at positions corresponding to the X-axis direction and the Y-axis direction. As shown in FIG. 3, each of these substrates 4 is made of an insulating material made of resin or the like in an arc shape. However, when the rigidity is low and flexibility is obtained, a flat plate is made into an arc shape. It may be bent and used, or if it has high rigidity, it may be preliminarily molded into an arc shape before use. And
On the inner peripheral surface 4a of each substrate 4, a pair of comb-teeth-shaped electrodes 5 and 5 which are in a non-conducting state are arranged.

The pressure-sensitive conductive elastomer molding 1
Does not necessarily have to be an integrally molded body, and may be, for example, one that is divided for each location where the electrodes 5 and 5 are provided. The locations of the electrodes 5 and 5 are not limited to four as described above, but may be three, five, or more. Furthermore, the electrodes 5 and 5 are not limited to the comb-teeth-shaped ones as described above, and other known electrodes may be used. Furthermore, instead of attaching the electrodes 5, 5 to the outer peripheral surface 1a of the pressure-sensitive conductive elastomer molded body 1, the electrode 5, 5 is formed on the inner peripheral surface 1b of the molded body 1.
It is also possible to attach 5.

The electrodes 5, 5, ... 5, 5 attached to the pressure-sensitive conductive elastomer molded body 1 are, as shown in FIG. 4, for example, control units via respective signal lines a, a to d, d. 6 is connected. The control unit 6 not only has a built-in power supply, but also has a built-in arithmetic circuit or microcomputer for executing a predetermined arithmetic operation based on the signals transmitted from the signal lines a, a to d, d. Has been done. In this case, the signal sent to the control unit 6 is taken out independently for each of the pair of electrodes 5, 5, and the signal lines a, a ...
One of the signal lines a to d of d and d can be electrically common.

Under the condition shown in FIG. 4,
Since the core rod 3 conforms to the Z axis and is not displaced, no pressure is applied to the pressure-sensitive conductive elastomer molded body 1, and therefore the conductive material mixed and dispersed in the molded body 1 is electrically conductive. The particles 1x ... 1x are separated from each other, and due to this, the molded body 1 is in an electrically insulating state. Therefore, all the electrodes 5 and 5 are not electrically connected to each other,
No signal is sent to the control unit 6.

On the other hand, as shown in FIG. 5, the core rod 3 is displaced to the right, and with this, the pressure-sensitive conductive elastomer molding 1 is formed.
When a partial compressive deformation occurs in the displacement direction part X of
The conductive particles 1x ... 1x around the displacement direction portion X are in contact with each other, and the electric resistance value around the portion X decreases. Therefore, the electrodes 5 and 5 communicating with the signal lines a and a are brought into a conductive state in response to the decrease in the electric resistance value, and the electric resistance change is taken out from the electrodes 5 and 5 and corresponds to the electric resistance change at this time. A signal is sent to the control unit 6 via the signal lines a and a. Then, the control unit 6 compares the signals from the signal lines a and a with the signals from the other signal lines b, b to d, and d, and determines that the core rod 3 is displaced to the right. to decide.

Further, as shown in FIG. 6, when the core rod 3 is displaced obliquely upward to the right, a partial compressive deformation occurs in the displacement direction portion Y of the molded body 1 and the electric resistance around this portion Y is increased. The value decreases. Along with this, the electrodes 5, 5 communicating with the signal lines a, a and the electrodes 5, 5 communicating with the signal lines b, b are brought into conduction at a predetermined ratio, and both signals indicating this are signaled. It is sent to the control unit 6 via the lines a, a and b, b. Therefore, the control unit 6 determines in which angle direction the core rod 3 is displaced diagonally upward to the right based on the ratio of both the signals from the signal lines a and a and the signals from the signal lines b and b. To do. Such an operation is similarly performed when the core rod 3 is displaced in any other angular direction. In the above, one signal is taken out from between the pair of adjacent electrodes 5 and 5 arranged only on the outer peripheral surface of the pressure-sensitive conductive elastomer molded body 1. However, instead of this, By disposing electrodes on the inner peripheral surface side and the outer peripheral surface side of the pressure-sensitive conductive elastomer molded body 1, one signal may be taken out between a pair of electrodes existing in the radial direction of both. .

FIG. 7 shows a second embodiment of the present invention. The difference between the second embodiment and the first embodiment is that the outer peripheral surface of the distal end of the cylindrical body 2 which is the cover member has a conical shape. Corresponding to this, the outer peripheral surface of the pressure-sensitive conductive elastomer molded body 1 has a conical shape, and the shape of the substrate 4 having the electrodes 5 and 5 is also fan-shaped as shown in FIG. It is what 7 and 8, constituent elements common to those of the first embodiment are designated by the same reference numerals, and the description thereof will be omitted. The cross-sectional shape of the second embodiment is the same as that shown in FIG. Since it is substantially the same as that shown, its illustration and description are omitted. Further, the operation and effect obtained from the second embodiment are also the same as those of the first embodiment, so the description thereof will be omitted.

FIG. 9 shows a third embodiment of the present invention. In the third embodiment, the present invention is applied to a core rod 3 having a rectangular cross section. Therefore, FIG.
As shown in, the inner peripheral surface 1b of the pressure-sensitive conductive elastomer molded body 1 is rectangular, and the rectangular inner peripheral surface 1b is also formed.
Substrates 4 ... 4 having electrodes on their sides are arranged. Specifically, as shown in FIG. 11, the electrodes 5, 5 are provided at four circumferential positions of the core rod 3 in the rectangular direction, that is, on each side surface 3 a ... 3 a of the core rod 3.
The flat plate-shaped substrates 4 having the above are respectively attached. As shown in FIG. 9, a cushion member 7 is provided between the core rod 3 and the tubular body 2 on the tip side of the pressure-sensitive conductive elastomer molded body 1 from the interposed location. In addition, the operational effect obtained from the third embodiment is also the same as that of the first embodiment.
The description is omitted because it is similar to the embodiment.

FIG. 12 shows a fourth embodiment of the present invention. In the fourth embodiment, the outer peripheral surface 1a of the pressure-sensitive conductive elastomer molding 1 is provided at a plurality of locations (four locations in the figure). , One of the electrodes 5 is arranged, and the core rod 3 is used as the other electrode (common electrode). Therefore, all or substantially all of the core rod 3 may be made of a conductive material, or only the portion acting as the common electrode or its peripheral portion may be made of a conductive material. In this case, although not shown, only one electrode 5 is provided for one substrate 4 as described above. Then, the electrodes 5 ... 5 and the core rod 3 on each one side
Are connected to the control unit 6 via signal lines a to e. Therefore, between the electrode 5 communicating with the signal line a and the core rod 3, between the electrode 5 communicating with the signal line b and the core rod 3, between the electrode 5 communicating with the signal line c and the core rod 3, and the signal line d. The electric resistance change due to the partial compressive deformation of the pressure-sensitive conductive elastomer molded body 1 is taken out from between the electrode 5 and the core rod 3 communicating with the control unit 6 based on the result.
Determines in what angle direction the core rod 3 is displaced.
It should be noted that, also in this case, the location of the one electrode 5 is not limited to four, and the cross-sectional shape of the core rod 3 is not limited to a circle, as described above. This is similar to the first embodiment.

The directional pressure sensing sensor according to the above embodiment is not only applicable to a type in which the core rod 3 moves, such as a writing device, but also a type in which the core rod 3 does not move, for example, a fixed type. It is also applicable to a displacement direction determination device of a type in which a contacted member such as paper, which comes into contact with the tip of the mandrel 3 that can be displaced in a state with a predetermined friction coefficient, moves.

[0019]

The directional pressure sensor according to the present invention is
Since it is configured as described above, it has the following effects. That is, according to the directional pressure sensor of claim 1, when a pressure is applied from the core rod to the pressure-sensitive conductive elastomer around the core rod to cause partial compression deformation, the pressure-sensitive conductive elastomer is produced. The electric resistance change corresponding to the partial compression is taken out from each pair of electrodes respectively arranged at a plurality of positions in the circumferential direction of, so that the direction of the pressing force acting on the pressure-sensitive conductive elastomer from the core rod, that is, The displacement direction of the core rod can be determined. Therefore, the directional pressure sensing sensor can be used as a displacement direction determination device, a handwriting measuring device, and the like, and can be used as a substitute for a mouse, a character input tablet, or the like, and its application can be expanded. Further, according to the directional pressure sensor of claim 2, when the pressure-sensitive conductive elastomer is partially compressed and deformed, the pressure-sensitive conductive elastomer is arranged at a plurality of positions in the circumferential direction of the pressure-sensitive conductive elastomer. The electric resistance change corresponding to the partial compressive deformation is taken out between the one electrode and the core rod which is the other common electrode, and the displacement direction of the core rod can be discriminated. The same effect as in the case of the above-mentioned claim 1. Will be obtained.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view of a main part showing a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG. 1 showing a first embodiment of the present invention.

FIG. 3 is a perspective view of a substrate, which is a component of the first embodiment of the present invention.

FIG. 4 is a schematic diagram showing an electrical connection state of the first embodiment of the present invention.

FIG. 5 is a schematic view showing the operation of the first embodiment of the present invention.

FIG. 6 is a schematic view showing the operation of the first embodiment of the present invention.

FIG. 7 is a vertical cross-sectional front view of essential parts showing a second embodiment of the present invention.

FIG. 8 is a perspective view of a substrate, which is a component of a second embodiment of the present invention.

FIG. 9 is a vertical cross-sectional front view of essential parts showing a third embodiment of the present invention.

FIG. 10 is a sectional view taken along line BB of FIG. 9 showing a third embodiment of the present invention.

FIG. 11 is a perspective view of a core rod and a substrate which are components of the third embodiment of the present invention.

FIG. 12 is a schematic view showing a fourth embodiment of the present invention.

[Explanation of symbols]

 1 Pressure Sensitive Conductive Elastomer 2 Cover Member (Cylinder) 3 Core Bar 4 Substrate 5 Electrode

Claims (2)

[Claims] 1. A structure having a core rod and a cover member surrounding the core rod, wherein a pressure-sensitive conductive elastomer is provided between the core rod and the cover member so as to cover the periphery of the core rod. A directional pressure sensor, characterized in that at least a pair of electrodes are provided at each of a plurality of positions in the circumferential direction of the pressure-sensitive conductive elastomer. 2. A pressure-sensitive conductive elastomer is provided between the core rod and the cover member so as to cover the periphery of the core rod in a structure having a core rod and a cover member surrounding the periphery of the core rod. A directional pressure sensing sensor, characterized in that one electrode is provided at each of a plurality of positions in the circumferential direction of the pressure-sensitive conductive elastomer, and the core rod serves as the other common electrode.