JP2002373541A - Sensor electrode - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress change of an output characteristic by reducing change of a proximity effective area, which comes from an electrode pattern and a movable point of contact, by errors in processing and assembling of a sensor electrode. SOLUTION: A load sensor consists of an electrode pattern 17, which is covered with resist 19 and is arranged on a substrate, a switch pattern 212, which consists of a pair of points of contact 20 and 20 and is apart form this electrode pattern 17, and a movable point of contact, which corresponds to the electrode pattern 17 and the switch pattern 21. On the other hand, the load sensor is constituted so that the load added to the movable point of contact may be sensed by change of the electric capacitance between the above electrode pattern 17 and the movable point of contact. Further, while forming the above electrode pattern 17 is formed into two half-annular shape symmetrical electrode patterns 17 and 17, these electrode patterns 17 and 17 are arranged oppositely and separately, and a sensor electrode 16, which is prepared with the above switch pattern 21 in the central part of these electrode patterns 17 and 17, is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sensor electrode, and more particularly, to a weight sensor for sensing a weight applied to a movable contact by a change in electric capacitance between the electrode pattern and the movable contact. The present invention relates to a sensor electrode in which a variation in an effective area close to a movable contact is reduced to suppress a variation in output characteristics.

[0002]

2. Description of the Related Art A conventional sensor electrode of this type will be described with reference to FIGS. In FIG. 4, reference numeral 1 denotes a sensor electrode. The sensor electrode 1 is provided with a C-shaped electrode pattern 3 having an opening 2 on a substrate covered with a resist 4. A switch pattern 6 including a pair of contacts 5 and 5 is provided at the center. The lead wires 7 of the switch pattern 6 extend outward through the opening 2 of the electrode pattern 3. In the figure, 8
Denotes a lead wire of the electrode pattern 3, and A denotes a proximity range of a movable contact described later.

[0005] In FIG. 5, reference numeral 9 denotes a weight sensor using the sensor electrode 1.
The sensor electrode 1 is disposed on the sensor electrode 1.
A movable contact 11 is provided above and above the sensor electrode 1, and the movable contact 11 is fixed to a lower portion of the rubber top 12. A flexible leg 13 is provided on the lower peripheral portion of the rubber top 12 so as to extend obliquely downward.
A foot 14 is disposed at the tip of the flexible leg 13, and the foot 1
4 is mounted on the substrate 10.

Further, a case cover 15 for holding the foot portion 14 from above and covering the lower half of the rubber top 12 and the sensor electrode 1 is provided, and penetrates the upper portion of the case cover 15. The key top portion 12a of the rubber top 12 projects upward.

When the key top portion 12a of the rubber top 12 is depressed, the flexible leg 13 bends, so that the movable contact 1 provided on the rubber top 12 is bent.
1 contacts the contacts 5 and 5 of the switch pattern 6 to make the contacts 5 and 5 conductive.

Further, when the key top portion 12a is depressed, the movable contact 11 is pressed into contact with the electrode pattern 3 via the resist 4 within the proximity range A, so that the movable contact 11 is located between the movable contact 11 and the electrode pattern 3. The capacitance changes. The weight of the pressing operation of the key top portion 12a can be sensed by the change in the capacitance.

However, in the sensor electrode 1,
Since the electrode pattern 3 is formed in a C-shape having the opening 2, if the proximity range A between the movable contact 11 and the electrode pattern 3 fluctuates due to a processing error and an assembly error of the weight sensor 9, The proximity effective area between the movable contact 11 and the electrode pattern 3 changes, and the output characteristics of the weight sensor 9 change.

Therefore, in the sensor electrode, there is a technical problem to be solved in order to reduce the fluctuation of the effective area close to the movable contact and the electrode pattern due to the processing error and the assembly error, and to suppress the fluctuation of the output characteristic. Therefore, the present invention aims to solve this problem.

[0009]

SUMMARY OF THE INVENTION The present invention has been proposed to achieve the above object. An electrode pattern is provided on a substrate so as to be covered with a resist, and is spaced apart from the electrode pattern. A switch pattern consisting of a pair of contacts is provided, while a movable contact is provided corresponding to the electrode pattern and the switch pattern, and a load applied to the movable contact is applied to an electric potential between the electrode pattern and the movable contact. In a weight sensor for sensing by a change in capacitance, the electrode patterns are formed into two symmetrical semi-annular electrode patterns, and the electrode patterns are opposed to each other, and are arranged apart from each other. A sensor electrode provided with the switch pattern at the center of the electrode pattern, and the electrode pattern is disposed on the substrate by being coated with a resist, and
A switch pattern consisting of a pair of contacts is provided at a distance from the electrode pattern, while a movable contact is provided corresponding to the electrode pattern and the switch pattern, and a load applied to the movable contact is applied to the electrode pattern. And a weighted sensor configured to sense by a change in capacitance between the movable contacts, wherein the electrode pattern is formed in an annular shape, and in the front-rear direction passing through the center of the electrode pattern,
An under resist having a predetermined width extending beyond both ends of the electrode pattern is applied, and further, the resist is coated on the electrode pattern and the under resist on the electrode pattern, and the switch pattern is formed at the center of the electrode pattern. And a sensor electrode in which a lead wire of the switch pattern is wired on the under resist and on the resist on the under resist.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to FIGS. For convenience of description, the same components as those of the conventional example are denoted by the same reference numerals, and description thereof will be omitted. In FIG. 1, reference numeral 16 denotes a sensor electrode. The sensor electrode 16 has two symmetrical semi-annular electrode patterns 17, 17 formed on a substrate so as to face each other and to be separated from each other. And the electrode patterns 17,
17 is connected by a connection line 18 and
9.

Further, a switch pattern 21 comprising a pair of contacts 20, 20 is provided at the center of the electrode pattern 17, and lead wires 22, 2 connected to the contacts 20, 20 are provided.
2 is the electrode pattern 1 covered with the resist 19
It extends outward through a gap in the front-rear direction between 7, 17. In the figure, reference numeral 23 denotes the electrode pattern 17 on the right side.
From the lead wire.

In FIG. 2, reference numeral 24 denotes a weight sensor. The weight sensor 24 is a conventional weight sensor 9 shown in FIG.
The sensor electrode 16 is used in place of the sensor electrode 1 described above.

When the key top portion 12a of the rubber top 12 is depressed, the flexible leg 13 bends, so that the movable contact 11 provided on the rubber top 12 contacts the contacts 20, 20 of the switch pattern 21. To make the contacts 20, 20 conductive.

Further, when the key top portion 12a is depressed, the movable contact 11 is pressed into contact with the electrode pattern 17 via the resist 19 within the proximity range A, and the movable contact 11 is pressed between the movable contact 11 and the electrode pattern 17. The capacitance changes. Then, the weight of the pressing operation of the key top portion 12a can be sensed from the change in the capacitance.

As described above, since the electrode pattern 17 is formed in two symmetrical semi-annular shapes as described above, the processing error and assembly of the weight sensor 24 and the sensor electrode 16 are formed. Even if the proximity range A between the electrode pattern 17 and the movable contact 11 fluctuates due to an error or the like, the electrode pattern 17 and the movable contact 1
The variation of the proximity effective area between the two is small, and therefore, the output characteristics of the weight sensor 24 constituted by the electrode pattern 17 and the movable contact 11 hardly vary.

In FIG. 3, reference numeral 25 denotes another sensor electrode. The sensor electrode 25 is provided with an electrode pattern 26 formed in an annular shape on a substrate and before and after passing through the center of the electrode pattern 26. In the direction, an under resist 27 having a predetermined width extending beyond both ends of the electrode pattern 26 is applied, and further, the electrode pattern 26 and the electrode pattern 26 are formed.
A resist 28 is coated on the under resist 27 provided thereon.

A switch pattern 30 having a pair of contacts 29, 29 is provided at the center of the electrode pattern 26, and a lead 3 of the switch pattern 30 is provided.
1 and 31 are wired on the under resist 27 and on the resist 28 on the under resist 27.
In the drawing, reference numeral 32 denotes a lead wire of the electrode pattern 26.

Accordingly, when a movable contact (not shown) is pressed onto the sensor electrode 25, the movable contact first contacts the switch pattern 28 to make the switch pattern 28 conductive, and when the movable contact is further pushed down, the movable contact A contact presses the electrode pattern 26 through the resist 28, and the pressing force is applied to the movable contact and the electrode pattern 26.
Change the capacitance between, by the change of the capacitance,
A change in the pressing force can be sensed.

As described above, the sensor electrode 25 has the electrode pattern 26 formed in an annular shape and extends beyond both ends of the electrode pattern 26 in the front-rear direction passing through the center of the electrode pattern 26. Since the under resist 27 having a predetermined width is applied, the electrode pattern 26 is formed.
Even if the proximity range A between the electrode pattern 26 and the movable contact fluctuates due to a processing error and an assembly error of the movable contact, the variation of the proximity effective area between the electrode pattern 26 and the movable contact is small. The output characteristics of the weight sensor constituted by the electrode pattern 26 and the movable contact hardly change.

The present invention can be variously modified without departing from the spirit of the present invention, and it goes without saying that the present invention extends to the modified ones.

[0021]

According to the present invention, as described in detail in the above embodiment, the invention according to claim 1 senses the load applied to the movable contact by the change in the electric capacitance between the electrode pattern and the movable contact. In the weight sensor having the above structure, the electrode pattern is formed into two symmetrical semi-annular electrode patterns, and the electrode patterns are arranged to be opposed to and separated from each other. Even if the proximity range between the electrode pattern and the movable contact fluctuates due to an electrode processing error and an assembly error, the proximity effective area variation between the electrode pattern and the movable contact is small. The output characteristics of the configured weight sensor hardly fluctuate.

According to a second aspect of the present invention, the electrode pattern is formed in an annular shape, and an under resist having a predetermined width extending beyond both ends of the electrode pattern is applied in a front-rear direction passing through the center of the electrode pattern. Furthermore, since the lead wire of the switch pattern is wired on the under-resist and the resist on the under-resist, an effect similar to that of the first aspect can be expected. is there.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention and is a plan view of a sensor electrode.

FIG. 2 shows an embodiment of the present invention and is a longitudinal sectional view of a weight sensor.

FIG. 3 shows another embodiment of the present invention, and is a plan view of a sensor electrode.

FIG. 4 shows a conventional example, and is a plan view of a sensor electrode.

FIG. 5 is a longitudinal sectional view of a weight sensor, showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Substrate 11 Movable contact 17, 26 Electrode pattern 19 Resist 21, 30 Switch pattern 24 Weight sensor 27 Under resist 29 Switch pattern 31 Lead wire

Claims (2)

[Claims] An electrode pattern is provided on a substrate so as to be covered with a resist, and a switch pattern comprising a pair of contacts is provided apart from the electrode pattern, while the electrode pattern and the switch pattern are provided on the substrate. A movable sensor is provided correspondingly, and the weight applied to the movable contact is detected by a change in electric capacitance between the electrode pattern and the movable contact. Are formed in two symmetrical semi-annular electrode patterns, the electrode patterns are arranged so as to face each other and are separated from each other, and the switch pattern is provided in the center of the electrode patterns. And the sensor electrode. 2. An electrode pattern is provided on a substrate by being coated with a resist, and a switch pattern including a pair of contacts is provided apart from the electrode pattern, while the electrode pattern and the switch pattern are provided on the substrate. A movable sensor is provided correspondingly, and the weight applied to the movable contact is detected by a change in electric capacitance between the electrode pattern and the movable contact. Is formed in an annular shape, and an under resist having a predetermined width extending beyond both ends of the electrode pattern is applied in a front-rear direction passing through the center of the electrode pattern, and further, the under resist on the electrode pattern and the electrode pattern The switch pattern is provided at the center of the electrode pattern, and the lead of the switch pattern is provided. A sensor electrode, wherein a wire is wired on the under resist and on the resist on the under resist.