JP3275120B2 - Capacitive force 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 sensor, and more particularly to a capacitive force sensor.

[0002]

2. Description of the Related Art As a capacitance type force sensor, for example, there is one as shown in FIG.

As shown in FIG. 1, this sensor has a diaphragm body 90a having a diaphragm portion 90 at the center and an operation shaft 91 at the center of the diaphragm portion 90, and is attached to the strain body 9a. A substrate K is provided between the strain generating body 9a and the substrate 9b. In the chamber K, the electrode portion C shown in FIG. On the 9b side, the electrode portions Cx +, Cx-,
The configuration is such that Cy + and Cy− are respectively attached. An electronic device 92 is mounted on the lower surface of the base 9b, and an annular plate 9c is arranged so as to surround the electronic device 92.

The above-described electronic device 92 includes an electrode portion C and an electrode portion Cx with a change in a gap G between the electrode plates 1 and 2.
+ For converting a change in capacitance between the electrodes C and Cx-, between the electrodes C and Cy +, and between the electrodes C and Cy- to a change in voltage, for example. There is.

Since the capacitance type force sensor is configured as described above, the magnitude and direction acting on the operation shaft 91 can be converted into corresponding positive / negative voltage values. Can be used as a cursor operation unit (a so-called joystick) displayed on a display.

[0006] However, this sensor has an operation shaft 9
Since the diaphragm unit 90 is deformed by applying a force to 1, the tilt amount of the operation shaft 91 is very small, and there is a problem that the operation shaft 91 does not have much operational feeling when used as a cursor operation unit.

[0007]

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a capacitive force sensor having an excellent operability when used as a cursor operation unit displayed on a display. .

[0008]

The capacitive force sensor according to the present invention comprises an upper substrate 1 having a hole 10 and a lower substrate 2 having an operation shaft 3 smaller in diameter than the hole 10 disposed on the upper surface. The operating shaft 3 is made to penetrate and protrude from the hole 10 and is urged upward by a spring B, so that the electrode portion C is formed on one of the opposing surfaces of the upper and lower substrates 1 and 2. And electrode portions Cx +, Cx-, Cy +, Cy- on the other side, and the electrode portion C and the electrode portions Cx +, Cx-, Cy +,
A small gap is formed between the operating shaft 3 and Cy-, and a bulging portion 52a is provided below the lower substrate 2 on the center axis of the operation shaft 3 so as to provide a small gap and protrude upward.

The capacitance type force sensor of the present invention has a hole 1
0, and a lower substrate 2 having an operation shaft 3 having a diameter smaller than that of the hole 10 disposed on the upper surface thereof. , And one of the upper and lower substrates 1 and 2 is made of a metal functioning as an electrode portion C, and the other side is provided with electrode portions Cx +, Cx−, Cy + and Cy−. A small gap is formed between the portion C and the electrode portions Cx +, Cx−, Cy +, Cy−, and a small gap is provided below the lower substrate 2 on the center axis of the operation shaft 3 to protrude upward. A bulge (52a) is provided.

Incidentally, regarding the above-mentioned capacitance type force sensor,
The bulging portion 52a preferably has an R-shaped cross section.

[0011]

The present invention operates as follows.

When a tilting force is applied to the operation shaft 3 protruding from the hole 10 of the upper substrate 1, the operation shaft 3 tilts against the urging force of the spring B. In comparison with the sensor for deforming the diaphragm described in (1), the amount of tilt is large. Also, spring B
By changing the strength (spring coefficient), the force detection sensitivity can be easily changed.

In the sensor of the present invention, the operation shaft 3
The posture of the lower substrate 2 changes with respect to the upper substrate 1 due to the above inclination, and the electrode portion C and the electrode portions Cx +,
Cx−, Cy +, and Cy− partially approach and move away from each other, and can be used as an operation unit of a cursor displayed on a display similarly to the sensors described in the related art section.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described with reference to the drawings shown as embodiments.

In this embodiment, a cursor operation section is formed by applying the capacitance type force sensor of the present invention to a keyboard. As shown in FIG. 1, an opening 51 formed in a key base plate 50 is provided. Then, the lower substrate 2 of the sensor is inserted so as to face the aluminum plate 52, and in this state, the upper substrate 1 of the sensor is screwed to the key base plate 50, and the entire sensor is attached to the keyboard.

As shown in FIG. 1, the capacitance type force sensor basically includes an upper substrate 1, a lower substrate 2 located below the upper substrate 1, and an operation formed on the upper surface of the lower substrate 2. Axis 3
And an electronic device 4 attached to the upper substrate 1.

As shown in FIG. 1 and FIG.
It is a substantially T-shaped plate made of a plate material made of CB (Print Circuit Board), and has a hole 10 large enough to allow a shaft main body 30 to be described later to be loosely inserted. It is arranged. On the surface of the upper substrate 1 facing the lower substrate 2, there are provided electrode portions Cx +, Cx-, Cy +, Cy- having the shapes as shown in FIGS. An annular spacer 11 thicker than the electrode portion is provided between the-, Cy +, and Cy- placement regions and the hole 20. When no external force is applied to the operation shaft 3, the electrode portion is Cx +, Cx-, Cy +, C
The y- and the lower substrate 2 do not come into contact with each other. In this embodiment, the electrode portions Cx +, Cx−, Cy +, Cy
A negative voltage is applied, and as shown in FIG. 4, both the connection and the connection are formed by etching or screen printing.

As shown in FIGS. 1 and 3, the lower substrate 2 is made of a conductive metal circular plate, and has a shaft main body 30 (upper region) constituting the operation shaft 3 in the center of its upper surface. Are male screw portions 30a). Although no electrode portion is formed on the lower substrate 2, the lower substrate 2 itself functions as an electrode portion.

As shown in FIGS. 1 and 2, the operating shaft 3 has the shaft main body 30 and a hollow portion 31a.
A thick shaft 31 made of resin screwed to the male screw portion 30a
It is composed of a metal washer 32 and a compression coil spring 33 which are disposed inside the hollow portion 31 a so as to be extrapolated to the shaft main body 30.

The lower end of the compression coil spring 33 is electrically connected to the GND (ground) electrode 12 formed on the upper surface of the upper substrate 1, and the lower substrate 2 is connected to the GND electrode 12 → compression. The grounding state is established along the path of the coil spring 33 → the washer 32 → the shaft main body 30.

The electronic device 4 includes an electrode portion C and an electrode portion Cx +
Between each other, between the electrode part C and the electrode part Cx-between, the electrode part C
The change in capacitance between the electrode part Cy + and the electrode part Cy +, and the change between the electrode part C and the electrode part Cy−,
x-, Vy +, Vy-, and X-
When the tilt amount of the operation shaft 3 in the X direction is [(Vx +)-(Vx
−)], The tilt amount of the operation shaft 3 in the YY direction is [(Vy
+)-(Vy-)], and the magnitude and magnitude of these voltages determine the moving speed and direction of the cursor displayed on the display.

Also, the aluminum plate 52 has a structure shown in FIGS.
As shown in FIG. 7, an upwardly protruding bulge 52a is formed on the center line of the shaft main body 30, and a small gap is formed between the top of the bulge 52a and the lower surface of the lower substrate 2. It is set to the height that is set.

Since the cursor operating portion of this embodiment has the above-described structure, when the upper end of the thick shaft 31 is pressed by a finger, the lower surface of the lower substrate 2 comes into contact with the bulging portion 52a against the urging force of the compression coil spring 33. When the tilting force is applied to the operation shaft 3 in this state, the posture of the lower substrate 2 changes from the state of FIG. 1 to the state of FIG. Therefore, as described in the section of the operation, the amount of tilt is larger than that of the sensor for deforming the diaphragm section described in the section of the prior art, so that an excellent operational feeling is obtained.

In the above embodiment, the lower substrate 2 is made of a conductive metal. However, the present invention is not limited to this.
The lower substrate 2 may be made of a hard synthetic resin. In this case, the electrode portion C may be formed on the upper surface of the lower substrate 2.

Further, in place of the above embodiment, an electrode portion C is formed on the upper substrate 1 side, and the electrode portions Cx +, Cx
−, Cy +, Cy− may be formed.

In place of the method of forming the electrode portion of the above-described embodiment, the electrode portion may be formed by insert molding a metal plate on the upper and lower substrates 1 and 2. Alternatively, the electrode portion may be formed by a printed board manufacturing method. A part may be formed.

On the other hand, regarding the capacitance type force sensor of the above embodiment, the electrode C or the electrode portions Cx +, Cx−, Cy +, C
It is preferable that at least one of y- is coated with an insulating paint.

[0028]

According to the above description, a capacitance type force sensor having an excellent operational feeling when used as an operation section of a cursor displayed on a display can be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a state in which a capacitance type force sensor according to an embodiment of the present invention is attached to a keyboard.

FIG. 2 is a sectional view showing a state in which an operation axis of the capacitance type force sensor is tilted.

FIG. 3 is an exploded perspective view of the capacitance type force sensor as viewed obliquely from below.

FIG. 4 is a diagram showing an electrode section formed on an upper substrate of the capacitance type force sensor.

FIG. 5 is a cross-sectional view of a prior art capacitive force sensor.

FIG. 6 is a plan view of an electrode portion on a strain body in a capacitance type force sensor according to the related art.

FIG. 7 is a plan view of a base-side electrode portion in a prior art capacitive force sensor.

[Explanation of symbols]

 B spring C electrode part Cx + electrode part Cx- electrode part Cy + electrode part Cy- electrode part 1 upper substrate 2 lower substrate 3 operation axis 10 hole

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Jundo Nakatsugawa 4-73, Sugaya, Ageo City, Saitama Prefecture Wako Co., Ltd. (72) Inventor Kazuhiro Okada 4-73, Sugaya, Ageo City, Saitama Prefecture Wako Co., Ltd. (56) References JP-A-59-23420 (JP, A) JP-A-60-238907 (JP, A) JP-A-4-277816 (JP, A) JP-A-60-50447 (JP, U) Table Hei 2-504079 (JP, A) US Patent 4,791,538 (US, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01L 5/16 G06F 3/033

Claims (3)

(57) [Claims] An upper substrate (1) having a hole (10), and a lower substrate (2) having an operation shaft (3) smaller in diameter than the hole (10) disposed on the upper surface. The operating shaft (3) is made to penetrate and protrude from the hole (10), and is urged upward by a spring (B).
The electrode part (C) is provided on one side of the opposing surfaces of (2),
On the other side, the electrode portion (Cx +) (Cx −) (Cy +) (Cy
-), And the electrode part (C) and the electrode part (Cx
+, (Cx-), (Cy +), and (Cy-), and a small gap is provided below the lower substrate (2) on the center axis of the operation shaft (3). A capacitive force sensor characterized in that a bulging portion (52a) protruding from the sensor is provided. 2. An upper substrate (1) having a hole (10), and a lower substrate (2) having an operation shaft (3) smaller in diameter than the hole (10) disposed on the upper surface. The operating shaft (3) is made to penetrate and protrude from the hole (10), and is urged upward by a spring (B).
One side of (2) is made of a metal that functions as an electrode section (C), and the other side has an electrode section (Cx +) (Cx
−) (Cy +) (Cy−), and a small gap is formed between the electrode part (C) and the electrode part (Cx +) (Cx −) (Cy +) (Cy−). A capacitance type force sensor characterized in that a bulging portion (52a) is provided below the lower substrate (2) on the center axis of (3) with a small gap provided and protruding upward. 3. The capacitive force sensor according to claim 1, wherein the bulging portion has an R-shaped cross section.