JPH06274265A - Face-like input device - Google Patents

Abstract

PURPOSE:To attain an analog and highly accurate input in accordance with force for compressively deforming pressure-sensitive conductive rubber by using pressure-sensitive conductive rubber obtained by blending fine conductive particles with specific size and setting up the height of an electrode step part to >10%. CONSTITUTION:A sheet-like pressure-sensitive conductive rubber 5 obtained by blending conductive particles with about several mum to several tens mum grain size is held between step parts (electrodes) 2, 4 and the height of the step parts 2, 4 is set up to about 10% the height of the rubber 5. When pressure P is applied to this input device, parts corresponding to the step parts 2, 4 out of the application part of the force on the rubber 5 are compressed, deformed and recessed to peripheral spaces 6, 7. The rubber 5 is easily and compressively deformed in accordance with the level of the pressure P and an electric resistance value is analogously reduced in accordance with the quantity of compressive deformation, so that conductivity can be recovered. When the pressure P is applied, an accurate input signal can be obtained by converting the applied position and level of the pressure P into an electric signal based upon the resistance change of the rubber 5 and inputting the electric signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a planar input device utilizing a pressure-sensitive conductive rubber containing fine conductive particles of several to several tens of millimeters.

[0002]

2. Description of the Related Art Conventionally, there has been a planar input device using a pressure-sensitive conductive rubber containing nickel particles having a particle size of about 50 to 100 μm or graphite having a particle size of about several to several tens of μm.

In the conventional device, a large number of elongated electrodes are provided in parallel on the insulating sheet in the x-axis direction, and on the other insulating sheet in parallel in the y-axis direction orthogonal to the x-axis. When the sheet-shaped pressure-sensitive conductive rubber sandwiched by a large number of elongated electrodes provided is compressed and deformed by the action of a force from the electrode side, the electric resistance of the pressure-sensitive conductive rubber decreases, and this resistance change Is input to equipment such as a computer by an electric signal.

However, the pressure-sensitive conductive rubber used in the apparatus is made by blending conductive nickel particles or graphite as described above, and the particle size of these conductive particles is relatively several to 100 μm. Since it is large, when a force is applied to the pressure-sensitive conductive rubber to compress it, the electric resistance is sharply reduced, and the relationship between such force and the electric resistance value is numerically very unstable.

The electrodes in the device are formed by printing a conductive paint on a flat insulating sheet and have a very small height of about 5 to 20 μm, which is suitable for pressure sensitive conductive rubber due to its deformation characteristics. Range of thickness is 0.2 to 2 mm
Is 10% or less. That is, the space in which the pressure-sensitive conductive rubber deforms and escapes when a force is applied is very small, and the compression deformation of the pressure-sensitive conductive rubber reaches the limit with a small amount. However, the pressure-sensitive conductive rubber is not compressed and no change in electric resistance is obtained.

Further, it has been confirmed that the force-electrical resistance relationship in the pressure-sensitive conductive rubber is different in the electric resistance value between the forward path (when pressure is applied) and the return path (when pressure is reduced). This is because the frictional resistance generated at the contact surface between the pressure-sensitive conductive rubber and the electrode significantly delays the shape recovery from the deformation of the pressure-sensitive conductive rubber.

As described above, in the conventional input device, in the pressure-sensitive conductive rubber used for the input device, the change of the electric resistance with respect to the change of the action of the force is not smooth, and the relationship between the force and the electric resistance value is a numerical value. Is extremely unstable, and the pressure-sensitive conductive rubber is less likely to undergo sufficient compressive deformation due to the structure of the device, and the electric resistance values during pressurization and depressurization are significantly different. It was impossible to accurately input to a device such as a computer in an analog manner according to the size of the.

[0008]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above problems, and is a pressure-sensitive conductive rubber containing fine conductive particles having a particle size of several to several tens of millimeters μm. To provide a highly reliable planar input device capable of accurately and analogally inputting to a device such as a computer in accordance with the magnitude of force for compressing and deforming the pressure-sensitive conductive rubber. The purpose is to

[0009]

A planar input device according to the present invention has a pair of opposing electrically insulating sheets having flexibility, one of which is in the x-axis direction and the other of which is the x-axis direction. In the y-axis direction orthogonal to the axis, a large number of elongated step portions which are electrodes wholly or electrically connected to each other are provided in parallel at minute intervals, and these electrodes in the x-axis direction and the y-axis direction are provided. , A sheet-shaped pressure-sensitive conductive rubber in which conductive particles having a particle size of several to several tens of μm are mixed (in the normal state, the electric resistance shows a high value, but when the deformation is caused by compression, the size of the deformation becomes large. It has a structure in which rubber whose electric resistance decreases according to the thickness is sandwiched, and the height of the step portion is 10% or more of the thickness of the pressure-sensitive conductive rubber.

The pressure-sensitive conductive rubber in the present invention is prepared by blending conductive particles having a particle size of several to several tens of millimeters μm. Specific examples of the conductive particles include carbon black. Since the conductive particles are very small, the force-electric resistance value relationship in the pressure-sensitive conductive rubber is very smooth,
stable. The thickness of the pressure-sensitive conductive rubber is preferably about 0.2 to 2 mm in view of deformation characteristics, but it may be appropriately changed depending on the use situation.

The electrically insulating sheet is preferably flexible but harder than the pressure-sensitive conductive rubber and inferior in deformability.

It is appropriate that the step portion is made of a material having high hardness and not deformed. The stepped portion has a height of 10% or more with respect to the thickness of the pressure-sensitive conductive rubber, and an appropriately large space is set in which the pressure-sensitive conductive rubber deforms and escapes when a force is applied. . As a result, the critical deformation amount of the pressure-sensitive conductive rubber is larger than that of the conventional one. It is to be noted that the interval between the parallel step portions is about the width of the step portion, but it may be appropriately changed depending on the use situation.

Further, in the stepped portion, the electrode surface in contact with the pressure-sensitive conductive rubber is rounded, and the contact area with the pressure-sensitive conductive rubber is adjusted to be small, thereby reducing the friction resistance between the rubber and the electrode. Cause the frictional resistance,
It is possible to reduce the difference between the electric resistance values when the pressure is applied and when the pressure is reduced.

[0014]

When the pressure is not applied to the planar input device of the present invention, since the pressure-sensitive conductive rubber is not deformed, the electric resistance of the pressure-sensitive conductive rubber shows a very high value.

However, when pressure is applied to this device, a portion of the force-acting portion of the pressure-sensitive conductive rubber corresponding to the step portion, particularly the position where the step portion in the x-axis direction and the step portion in the y-axis direction intersect. The portion corresponding to is given a significant compression and sufficiently deforms and escapes into the space formed between the adjacent step portions. The pressure-sensitive conductive rubber is easily compressed and deformed according to the magnitude of the force, and the electrical resistance value is reduced in an analog manner according to the amount of compressed deformation, and the conductivity is restored. The position where the force is applied, that is, the position where the electric resistance is reduced, is confirmed by the coordinates of the x-axis and the y-axis in the two-layer electrodes sandwiching the pressure-sensitive conductive rubber, and the x-coordinate is the y-axis direction. And the y-coordinate is confirmed by the electrodes aligned in the x-axis direction.

Further, when the force acting on the present invention is released, the pressure-sensitive conductive rubber returns to the initial shape due to its excellent shape restoring property, so that the electric resistance also becomes the initial high value.

As described above, according to the present invention, when pressure is applied to an arbitrary position on the device surface, the position and the magnitude of the force are calculated by an electric signal due to a resistance change of the pressure-sensitive conductive rubber. Different from the conventional one, the pressure-sensitive conductive rubber formed by mixing fine conductive particles having a particle size of several to several tens of millimeters μm is used, and the pressure-sensitive conductive rubber deforms and escapes. Since the space is set to be appropriately large, it is possible to accurately and analogically input the pressure-sensitive conductive rubber in accordance with the magnitude of the force that compressively deforms the rubber.

Further, as described above, in the step portion of the present invention, by rounding the electrode surface in contact with the pressure-sensitive conductive rubber and adjusting the contact area with the pressure-sensitive conductive rubber to be small, the rubber can be reduced. The present invention can be made more precise by reducing the frictional resistance between the electrode and the electrode, and reducing the deviation of the electric resistance value between the pressure application and the pressure reduction caused by the frictional resistance.

The input forms in the planar input device are roughly classified into point input, line input, and surface input. The point input is used as an enlarging / reducing editing device in a copying machine, and line input. An example is a handwriting input device for a display, and an example for surface input is a pressure distribution measuring device. Conventional planar input devices are generally used for simple point input and handwriting input,
Some of the devices used as pressure distribution measuring devices also have problems in accuracy and stability, whereas the device according to the present invention is excellent in that it can accurately input in analog according to the magnitude of force. Since it has the performance, it is very suitable for use, for example, when it is desired to represent the delicate strength of force on a display in handwriting input, or as a device for measuring the pressure distribution state.

[0020]

EXAMPLES Examples of the present invention will be described below.
It is not limited by this.

FIGS. 1 to 3 show a first embodiment of the present invention.

In this embodiment, a large number of elongated prismatic step portions 2 are formed on one side of an electrically insulating sheet-shaped polyester 1.
Are provided in parallel in the x-axis direction at minute intervals.
The step portion 2 is made of conductive phosphor bronze, is electrically connected, and functions as an electrode. On the other hand, on one surface of the sheet-shaped polyester 3, a large number of stepped portions 4 made of phosphor bronze are provided in parallel at a minute interval in the y-axis direction orthogonal to the x-axis, as described above. These step portions (that is, electrodes) 2 and 4 sandwich a sheet-shaped pressure-sensitive conductive rubber 5 containing conductive carbon black having a particle size of several to several tens of millimeters μm, and therefore, the step portions. A large number of spaces 6 are formed between the polyester 1 and the pressure-sensitive conductive rubber 5 via the step 2, and a large number of spaces 7 are formed between the pressure-sensitive conductive rubber 5 and the polyester 3 via the step portion 4. Has been done. The polyesters 1 and 3 and the pressure-sensitive conductive rubber 5 have a thickness of 500 μm, and the steps 2 and 3 have a width of 1 μm.
The height is 200 μm and the height is 200 μm, and they are arranged in parallel at intervals of 200 μm.

Next, the operation of this embodiment will be described.

As shown in FIG. 2 (however, all cross-sectional views seen from the x-axis direction), the pressure-sensitive conductive rubber 5 is not deformed when the pressure P is not acting on the device. The electric resistance of the pressure-sensitive conductive rubber 5 shows a very high value.

However, as shown in FIG. 3 (however, a cross-sectional view as seen from the x-axis direction), when the pressure P of the apparatus acts,
Out of the force-acting portion of the pressure-sensitive conductive rubber 5, a portion corresponding to the step portion 2 and the step portion 4, particularly a portion corresponding to a position where the step portion 2 and the step portion 4 intersect with each other, is given a significant compression, It deforms to the spaces 6 and 7 and escapes. In this way, the pressure-sensitive conductive rubber 5 is easily compressed and deformed according to the magnitude of the pressure P, and the electrical resistance value is reduced in an analog manner according to the amount of compressed deformation, and the conductivity is restored. The position where the pressure P acts, that is, the position where the electric resistance decreases, is confirmed by the steps of the pressure-sensitive conductive rubber 5, that is, the coordinates of the x-axis and the y-axis in the electrodes 2 and 4. The x coordinate is confirmed by the electrode 4 and the y coordinate is confirmed by the electrode 2.

When the pressure P acting on the apparatus is released, the pressure-sensitive conductive rubber 5 returns to the initial shape due to its excellent shape restoring property, and therefore the electric resistance becomes high again.

As described above, when the pressure P acts on an arbitrary position on the surface of the apparatus, the position and the magnitude of the pressure P are
The pressure-sensitive conductive rubber 5 is input to a device such as a computer by an electric signal due to a resistance change, and can be accurately input in an analog manner according to the magnitude of the pressure P.

FIG. 4 shows a second embodiment of the present invention.

In this embodiment, a large number of elongated prismatic steps 9 are provided on one side of an electrically insulating sheet-shaped polyester 8.
Are provided in parallel in the x-axis direction at minute intervals.
The step portion 9 has an electrode 9a made of phosphor bronze and electrically connected to an upper portion of a polyester base 9b. On the other hand, on one side of the sheet-shaped polyester 10, a large number of stepped portions 11 each having a phosphor bronze electrode 11a on the polyester base 11b are formed in the y-axis direction orthogonal to the x-axis, as described above. They are provided in parallel at minute intervals. The electrodes 9a and 11a sandwich the sheet-shaped pressure-sensitive conductive rubber 12 similar to that in the first embodiment. Therefore, a large number of spaces 13 are provided between the polyester 8 and the pressure-sensitive conductive rubber 12 via the step portion 9. In addition, a large number of spaces 14 are formed between the pressure-sensitive conductive rubber 12 and the polyester 10 via the step portion 11. In addition, polyester 8, 1
0 and the thickness of the pressure-sensitive conductive rubber 12 are each 500 μ.
m, the steps 9 and 11 have a width of 100 μm and a height of 200 μm (of which the heights of the electrodes 9a and 11a are 50 μm) and are arranged in parallel at intervals of 200 μm.

FIG. 5 shows a third embodiment of the present invention.

In this embodiment, a plurality of elongated step portions 16 are provided on one surface of the electrically insulating sheet-shaped polyester 15.
Are provided in parallel in the x-axis direction at minute intervals.
On the other hand, on one side of the sheet-shaped polyester 17,
A large number of step portions 18 are provided in parallel in the y-axis direction orthogonal to the x-axis at minute intervals. These step portions 16 and 18 are electrically connected electrodes 1 obtained by applying a silver-based conductive paint to the rounded portions of the bases 16b and 18b of polyester having rounded upper portions.
6a and 18a. The electrodes 16a and 1
8a sandwiches the sheet-like pressure-sensitive conductive rubber 19 similar to that in the first and second embodiments. Therefore, a large number of spaces 20 are provided between the polyester 15 and the pressure-sensitive conductive rubber 19 via the step portion 16. Further, a large number of spaces 21 are formed between the pressure-sensitive conductive rubber 19 and the polyester 17 via the step portion 18. The thickness of each of the polyesters 15 and 17 and the pressure-sensitive conductive rubber 19 is 500 μm, and the step portion 1
6 and 18 have a width of 100 μm and a height of 200 μ
m (of which the maximum height of the electrodes 16a and 18a is 3
0 μm) and arranged in parallel at intervals of 200 μm.

The operation of the second and third embodiments is the same as that of the first embodiment. In the third embodiment, the surfaces of the electrodes 16a and 18a contacting the pressure-sensitive conductive rubber 19 are rounded, and the contact area with the pressure-sensitive conductive rubber 19 is adjusted to be small. 19 and electrode 16
The frictional resistance between a and 18a is suppressed to a low level. Therefore, the difference between the electric resistance values of the pressure-sensitive conductive rubber 19 during pressurization and depressurization, which is caused by the frictional resistance, is extremely small. It enables highly accurate and reliable input.

[0033]

As described above, the planar input device according to the present invention can (a) accurately input in an analog manner according to the magnitude of force. It is very suitable when you want to display subtle strengths and weaknesses on a display or as a pressure distribution measuring device. (B) It has a simple structure and can be manufactured at low cost. (C) By adjusting the shape of the electrodes, it is possible to eliminate the phase shift between the electrical signals due to the actual pressure magnitude and resistance change. And so on.

[Brief description of drawings]

FIG. 1 is a perspective view showing a first embodiment of a planar input device according to the present invention.

FIG. 2 is a full sectional view of the first embodiment seen from the x-axis direction in a state where no pressure P acts.

FIG. 3 is a full cross section of the first embodiment as seen from the x-axis direction in a state where a pressure P is applied.

FIG. 4 is a full sectional view of the second embodiment according to the present invention as viewed from the x-axis direction, in the state in which the pressure P is not applied.

FIG. 5 is a full sectional view of the third embodiment according to the present invention as seen from the x-axis direction when pressure P is not acting.

[Explanation of symbols]

 P pressure 1 sheet-like polyester 2 steps (electrode) 3 sheet-like polyester 4 steps (electrode) 5 sheet-like pressure-sensitive conductive rubber 6 space 7 space 8 sheet-like polyester 9 steps 9a electrode 9b polyester base 10 sheet-like polyester 11 steps 11a electrode 11b polyester base 12 sheet pressure-sensitive conductive rubber 13 space 14 space 15 sheet polyester 16 steps 16a electrode 16b polyester base 17 sheet polyester 18 steps 18a electrode 18b polyester base 19 sheet feeling Piezoelectric conductive rubber 20 space 21 space

Claims (2)

[Claims] 1. A pair of opposing electrically insulating sheets having flexibility, one of which faces in the x-axis direction,
On the other hand, in the y-axis direction orthogonal to the x-axis, a large number of elongated step portions which form electrodes whose whole or upper part is electrically connected are provided in parallel at minute intervals. A sheet-shaped pressure-sensitive conductive rubber in which the electrode in the y-axis direction is mixed with conductive particles having a particle size of several to several tens of millimeters μm (in the normal state, electric resistance shows a high value, but is deformed by compression. And a rubber whose electrical resistance decreases according to the size of the deformation) is sandwiched, and the height of the step portion is 10% or more of the thickness of the pressure-sensitive conductive rubber. A planar input device characterized by. 2. The planar input device according to claim 1, wherein in the step portion, an electrode surface which comes into contact with the pressure-sensitive conductive rubber is rounded so that a contact area with the pressure-sensitive conductive rubber is adjusted to be small.