JPH06324801A - Capacitance type sensor - Google Patents

Abstract

PURPOSE:To provide a capacitance type sensor which has high sensitivity, and also, whose sensitivity is not varied by an atmospheric temperature. CONSTITUTION:This sensor is provided with a substrate 1 having an electrode part C on one face, a substrate 2 which is provided so as to be opposed to the substrate 1, and also, has electrode parts Cx+, Cx-, Cy+ and Cy- arranged at 90 deg. angle intervals on one face, and an input part J provided in at least one of the substrates 1, 2, and the electrode part C and the electrode parts Cx+, Cx-, Cy+ and Cy- are covered with a non-conductive thin film ('Teflon(R)' coating TC) whose thermal expansion coefficient is small, respectively, and also, at least one of the substrates 1, 2 is energized in order that the non-conductive thin film of the electrode part C side and that of the electrode parts Cx+, Cx-, Cy+ and Cy-side are in press-contact with each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a capacitance type sensor, and can be used, for example, as an operating unit for moving a cursor displayed on a computer display as desired.

[0002]

2. Description of the Related Art Examples of this type of sensor include those shown in FIGS. As shown in the figure, this sensor is a substrate 90 having an input shaft portion 90a in the central portion.
A substrate 91 disposed opposite to the substrate 90, an electrode portion C provided on the lower surface of the substrate 90, and electrode portions Cx +, Cx−, Cy +, Cy− provided on the upper surface of the substrate 91.
And a thin elastic plate 92 interposed between the upper and lower electrode portions described above, and the pressing member 9 provided on the substrate 91.
The upper surface of the substrate 91 is pushed in by means of 9.
Further, an electronic device 93 is provided on the lower surface of the substrate 91 of this sensor as shown in FIG. 7, and by this electronic device 93, between the electrode portion C and the electrode portion Cx +, between the electrode portion C and the electrode portion Cx−. A change in capacitance between the electrodes C and the electrode Cy + and between the electrodes C and Cy- can be converted into a voltage change.

Therefore, when the upper end portion of the input shaft portion 90a is displaced in the vertical / horizontal direction (X-X direction, Y-Y direction) with a finger, the urging force of the elastic plate 92 is resisted between the electrode portions. The gap G of each portion changes, and as a result, the displacement (direction and amount) of the input shaft portion 90a in the pressing direction can be taken out as a voltage output. When this sensor is used as a movement operation unit of the cursor displayed on the display, it may be incorporated in such a manner that only the upper end of the input shaft 90a projects from the upper wall of the keyboard KB as shown in FIG. 7, and the gap G changes. The moving speed and the moving direction of the cursor may be determined according to the magnitude of the voltage output value accompanying the above.

However, when this sensor is used as the cursor operating portion as described above, the amount of contraction / expansion of the elastic plate 92 changes depending on the ambient temperature, so the upper end of the input shaft 90a is displaced by the same amount. However, the moving speed of the cursor differs depending on the ambient temperature.
That is, this sensor has a problem that the sensitivity changes depending on the ambient temperature.

Further, in order to obtain a feeling of operation, the input shaft portion 90a
Since the thickness of the elastic plate 92 must be increased in order to make the displacement of the electrode to a certain extent, the electrostatic capacitance between the electrode portions cannot be made large. Therefore, in the above configuration,
There is also a problem that it is difficult to manufacture a highly sensitive sensor. In recent years, there is a demand for development of a capacitance type sensor that is highly sensitive and does not change in sensitivity depending on the ambient temperature, not only when used as a cursor operation unit.

[0006]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a capacitance type sensor which has high sensitivity and whose sensitivity does not change depending on the ambient temperature.

[0007]

According to the capacitance type sensor of the present invention, a substrate 1 having an electrode portion C on one side, and a 90 ° angular interval on one side which is disposed so as to face the substrate 1. The electrode parts Cx +, Cx−, Cy +, Cy arranged in
A substrate 2 having-and an input part J provided on at least one of the substrates 1 and 2, and the coefficient of thermal expansion of the electrode part C and the electrode parts Cx +, Cx-, Cy +, Cy-, respectively. Of non-conductive thin film 4 having a small
The non-conductive thin film 4 on the side of the electrode portion C and the electrode portions Cx +, Cx
At least one of the substrates 1 and 2 is energized so as to make pressure contact with that on the −, Cy +, and Cy− sides.

According to another aspect of the present invention, there is provided a capacitance type sensor in which a substrate 1 made of a conductive material is provided, and the substrate 1 is disposed so as to face the substrate 1 and has an angle of 90 ° on one side. A part and an electrode which are provided with a substrate 2 having electrode parts Cx +, Cx−, Cy +, Cy− and an input part J provided on at least one of the substrates 1 and 2 and serving as electrodes of the substrate 1. Part Cx +, Cx-, Cy +, Cy
-Is coated with a non-conductive thin film 4 having a small coefficient of thermal expansion, and the non-conductive thin film 4 on the side of the substrate 1 and the electrode portion Cx.
It is assumed that at least one of the substrates 1 and 2 is urged so as to be brought into pressure contact with the +, Cx-, Cy +, and Cy-side ones.

[0009]

The present invention has the following actions. (Operation of the invention of claim 1) In this capacitance type sensor, the electrode portion C and the electrode portions Cx +, Cx-, Cy +, Cy are provided.
Since there is only the non-conductive thin film 4 between − and −, the distance between the electrode portion C and the electrode portions Cx +, Cx−, Cy +, Cy− becomes extremely small as compared with the conventional one, and as a result, It is possible to increase the capacitance between the electrode parts.

Further, since the non-conductive thin film 4 has a small coefficient of thermal expansion, it is hardly affected by the ambient temperature and the sensitivity is good. (Operation of the invention described in claim 2) In this capacitance type sensor, the electrode portion of the substrate 1 and the electrode portions Cx +, Cx are provided.
Since only the non-conductive thin film 4 is between −, Cy +, and Cy−, the portion that becomes the electrode portion of the substrate 1 and the electrode portion Cx
The distance between +, Cx−, Cy +, and Cy− is extremely smaller than that of the conventional one, and as a result, the capacitance between the electrode portions can be increased.

Further, since the non-conductive thin film 4 has a small coefficient of thermal expansion, it is hardly affected by the ambient temperature and has a good sensitivity.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the invention of this application will be described below with reference to the drawings shown as embodiments. (Embodiment 1) In this embodiment, since the capacitance type sensor of the present invention is adopted as a moving operation portion of a cursor displayed on a display, the sensor is incorporated in a keyboard KB as shown in FIG. The input shaft portion 10 serving as an operation portion is projected from a circular opening h provided in the upper wall of the keyboard KB.

As shown in FIG. 1, the capacitance type sensor has a substrate 1 having an input shaft portion 10 on an upper surface and an electrode portion C on a lower surface, and a substrate 1 arranged to face the substrate 1 and having an upper surface. It is provided with a substrate 2 having an electrode portion C ′ and an electronic device 3 arranged on the lower surface portion of the substrate 2, wherein the electrode portions C and C ′ are each provided with a Teflon coating TC (non-conductive in the column of means). Corresponding to the elastic thin film 4 and set to a thickness of about 10 to 50 μ), and an annular elastic plate 53 (made of a material ...) Attached to the lower surface of the holding member 5 screwed to the substrate 2.
・) Teflon coating T of each electrode part C, C '
The C surfaces are pressed against each other.

The substrate 1 is made of a circular synthetic resin plate. As shown in FIGS. 1 and 2, a sensor is attached to the keyboard KB of the input shaft portion 10 provided in the central portion of the upper surface thereof. 5 from the top wall of the keyboard KB in the state
The length is set so as to project by about 10 mm. On the other hand, the electrode portion C provided in the central portion of the lower surface of the substrate 1 is formed by printing copper in a circular shape as shown in FIG.

As shown in FIG. 1, the substrate 2 is composed of a circular synthetic resin plate having a diameter larger than that of the substrate 1, and the above-mentioned electrode portion is formed by copper printing in the manner shown in FIG. C '
(Electrode portions Cx +, Cx−, Cy +, Cy−) are formed. The center of the above-mentioned electrode portion C is the electrode portion C.
It is arranged so as to coincide with the arrangement center of x +, Cx−, Cy +, Cy− in a plan view.

The pressing member 5 is, as shown in FIG. 1 and FIG.
It comprises a cylindrical portion 50 and an upper wall 51 having a through hole 52 for projecting the input shaft portion 10 therethrough, and is formed by attaching an annular elastic plate 53 to the lower surface of the upper wall 51. There is. The electronic device 3 includes the electrode portion C and the electrode portions Cx +, Cx.
Capacitances corresponding to the mutual distances between −, Cy +, and Cy− can be converted into voltages Vx +, Vx−, Vy +, and Vy−, respectively.

In this embodiment, when the input shaft portion 10 is displaced (tilted) in the XX direction, the amount of displacement is [(Vx +)-(Vx-)] in the YY direction. When the input shaft portion 10 is displaced to the position, the displacement amount is [(Vy +)-
(Vy−)], and the moving speed of the cursor is determined by this voltage value. That is,
Since this capacitance type sensor is configured as described above, when the input shaft portion 10 is operated to displace the substrate 1 to the right side in the XX direction with respect to the substrate 2 as shown in FIG. The voltage becomes (Vx +)-(Vx-)> 0, and the cursor moves to the right at a speed corresponding to the absolute value of [(Vx +)-(and Vx-)]. On the contrary, when it is displaced to the left in the XX direction, the output voltage is (Vx +)-(Vx
−) <0, and the cursor is [(Vx +) − (Vx
-)] Moves to the left at a speed corresponding to the absolute value of. or,
By operating the input shaft portion 10 with a finger, the board 1 is moved relative to the board 2.
The same applies to the case of displacement in the −Y direction as in the case of the XX direction.

In the capacitance type sensor of this embodiment, the electrode portion C and the electrode portions Cx +, Cx−, Cy +, Cy− are coated with Teflon TC, and the electrode portion C,
Since C ′ is pressed against each other by the elastic restoring force of the annular elastic plate 53, the electrode portion C and the electrode portions Cx +, Cx are connected.
The distance between −, Cy +, and Cy− is (10 μ to 50 μ) ×
2. As a result, when compared with the conventional one having the elastic plate, the electrode portion C and each electrode portion Cx +, Cx are compared.
A large electrostatic capacitance between −, Cy +, and Cy− can be obtained. Further, since the Teflon coating TC is used, the surface thereof is hard and the coefficient of thermal expansion is small, and as a result, the sensitivity is not easily influenced by the pushing force into the input shaft portion 10 and the ambient temperature.

Further, in this embodiment, the space K formed by the substrate 1, the substrate 2, the pressing member 5 and the annular elastic plate 53 is in a hermetically sealed state, so that dust or the like is left between the Teflon-coated TC surfaces. It will not happen that there is a pinch, and the sensitivity as a sensor will be even better. In the above embodiment, the electrode portion C ′ may have the electrode portions Cx +, Cx−, Cy +, Cy−, Cz, and in this case, X− acting on the input shaft portion 10 is used.
The forces in the three directions Y-Z can be taken out as voltage outputs.

Further, in the above embodiment, the electrode portion C may be composed of the electrode portions Cx +, Cx−, Cy +, Cy−. Further, in the above-mentioned embodiment, the annular elastic plate 53 is used as a means for pressing the Teflon coating TC surfaces of the electrode portion C side and the electrode portion C ′ side to each other, but the present invention is not limited to this, and a compression spring or the like can also be used. In addition, FIG.
With such a structure, the tension spring B can also be used.

In the above embodiment, the non-conductive thin film 4 is made of Teflon coating TC. However, the material is not limited to this, and other materials may be used as long as they are non-conductive and have a hard finish. it can.

[0022]

Since the present invention has the structure as described above, it has the following effects. From the contents described in the action, it was possible to provide a capacitance-type sensor that has high sensitivity and whose sensitivity does not change depending on the ambient temperature.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a capacitance type sensor according to an embodiment of the present invention mounted in a keyboard as an operation unit for moving a cursor displayed on a display.

FIG. 2 is a perspective view of the capacitance type sensor.

FIG. 3 is a diagram showing an electrode portion provided on an upper substrate of the capacitance type sensor.

FIG. 4 is a view showing an electrode portion provided on a lower substrate of the capacitance type sensor.

FIG. 5 is a view showing a state in which the input shaft portion is displaced to the right from the state of FIG.

FIG. 6 is a sectional view of a capacitance type sensor according to another embodiment of the present invention.

FIG. 7 is a cross-sectional view of a capacitive sensor according to the related art mounted in a keyboard as an operation unit for moving a cursor displayed on a display.

FIG. 8 is a diagram showing an electrode portion of an upper substrate of a capacitance type sensor of the prior art.

FIG. 9 is a view showing an electrode portion of a lower substrate of a capacitance type sensor of the prior art.

[Explanation of symbols]

 J input part C electrode part Cx + electrode part Cx− electrode part Cy + electrode part Cy− electrode part 1 substrate 2 substrate 3 non-conductive thin film

Claims (2)

[Claims] 1. A substrate (1) having an electrode portion (C) on one surface thereof.
And electrode portions (Cx +) (Cx−) (Cy) which are arranged to face the substrate (1) and are arranged on one side at 90 ° angular intervals.
A substrate (2) having +) (Cy−), and the substrate (1)
The input section (J) provided in at least one of (2), and the electrode section (C) and the electrode section (Cx).
+) (Cx −) (Cy +) (Cy−) is covered with a non-conductive thin film (4) having a small coefficient of thermal expansion, and the non-conductive thin film (4) and the electrode part on the side of the electrode part (C) are also covered. (Cx
A capacitive sensor characterized in that at least one of the substrates (1) and (2) is urged so as to make pressure contact with that on the (+) (Cx −) (Cy +) (Cy−) side. 2. A substrate (1) made of an electrically conductive material, and a substrate (1) which is disposed so as to face the substrate (1) and is provided on one side thereof.
Electrode parts (Cx +) (Cx-) arranged at 0 ° angular intervals
A substrate (2) having (Cy +) (Cy−), and an input unit (J) provided on at least one of the substrates (1) and (2), the electrode of the substrate (1). And electrode part (Cx +) (Cx-) (Cy +) (C
y-) is a non-conductive thin film (4) having a small coefficient of thermal expansion.
And the non-conductive thin film (4) on the side of the substrate (1) and the electrode parts (Cx +) (Cx −) (Cy +) (Cy
A capacitive sensor characterized in that at least one of the substrates (1) and (2) is urged so as to come into pressure contact with that on the −) side.