JP2000276966A - Movable contact body and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a movable contact capable of exactly executing contact switch functions irrespective of the size of a contact and provide a manufacturing method thereof. SOLUTION: In this movable contact, an electrical short circuit is made in a pair of comb teeth-shaped electrodes of a contact 31a by causing conductive carbon ink 22 printed on a circular contact part 20 to abut on the fixed contact 31a, thus providing a function of a contact switch. Prior to the printing of the ink 22, a substantially circular dish-shaped recessed surface 21 is formed on an ink-print end of the contact 20 of the movable contact body 11. A flat part 21a is provided substantially in a middle of the recessed surface 21. The liquid carbon ink 22 is printed on the recessed surface 21 by a predetermined pin and solidified, thus forming the contact 20. The film thickness of the ink 22 is increased by the depth of the recess of the recessed surface 21. Also, an arc-shaped contact 23 is formed in a similar manner.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a movable contact body which is disposed opposite to a fixed contact such as a comb-like electrode pattern, and which performs a contact switch function when a contact portion comes into contact with or separates from the fixed contact. More particularly, the present invention relates to a movable contact body in which a contact portion is formed by printing a conductive material, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, there has been known a switch body in which a comb-shaped fixed contact pattern is formed on a substrate, and a movable contact body is arranged to face the fixed contact pattern. This switch body
For example, it is used for key press detection of an electronic keyboard device. This switch body is configured to perform a contact switch function when a contact portion provided on the movable contact body comes into contact with or separates from a fixed contact pattern. Generally, the movable contact body is integrally formed of an elastic resin or the like, and a contact portion is formed by providing a conductive material such as carbon ink at an end for the contact. And
The ON of the contact switch is detected by the conductive material of the contact portion contacting the fixed contact pattern and electrically short-circuiting a plurality of adjacent comb tooth patterns.

[0003] The contact portion of the movable contact body is, for example, a conductive fluid such as carbon ink adhered to a pin, printed on an end (for example, a circular shape) for the contact, and solidified by heating and drying. Formed by In this movable contact body, the end for the contact before the conductive fluid is printed is usually a flat surface regardless of the size of the movable contact body due to a requirement in manufacturing a mold.

[0004]

However, if the keyboard device or the like using the movable contact body is small, the size of the contact end on which the conductive fluid is printed must be reduced. In this case, if the conductive fluid is printed through the same process uniformly, the smaller the size of the end portion for the contact, the smaller the film thickness after the conductive fluid is solidified. For example, if the size of the end for the contact has to be further reduced due to the relationship with the fixed contact or the necessity of a concentric double contact, the thickness of the conductive material is extremely thin (about half). Sometimes it becomes. As a result, there has been a problem that the conductivity of the contact portion at the time of contact with the fixed contact pattern is deteriorated, the resistance value is increased, and there is a possibility that the switch is not turned on and erroneous detection is performed.

Here, in order to increase the film thickness after solidification,
It is also conceivable to increase the viscosity and concentration of the conductive fluid. However, if the viscosity or concentration is excessively high, the solidification tends to solidify in a dumpling shape, and the contact portion tends to be protruded. If the protruding tendency is too large, the contact area between the contact portion and the fixed contact pattern becomes small and the adjacent comb-tooth pattern cannot be short-circuited sufficiently. In addition, it is not easy to stably maintain the viscosity and concentration of the conductive fluid at a high value, and it is not easy to control the film thickness to a desired value based on the viscosity value and the concentration value.

According to an experiment conducted by the present applicant, in the case where the size of the contact portion such as the diameter is small and the size is the same, the conductive material having a larger thickness is more resistant to the contact portion at the time of contact with the contact. The value was found to be low. That is,
It became clear that the resistance value largely depends not only on the size but also on the film thickness.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide a movable contact body capable of accurately performing a contact switch function regardless of the size of a contact portion, and a method of manufacturing the same. Is to provide.

[0008]

According to a first aspect of the present invention, a movable contact body is provided so as to face a fixed contact (31) provided on a substrate. A movable contact body having a contact portion (20) formed by printing a conductive material (22) on a predetermined opposing surface (21), and performing a contact switch function by separating and contacting the fixed contact with the fixed contact; (11), wherein the predetermined surface of the movable contact body before printing the conductive material is formed in a concave shape.

According to this configuration, the predetermined surface of the movable contact body before forming the conductive material is formed in a concave shape.
The predetermined surface formed in the concave shape is filled with the conductive material, and the thickness of the conductive material after printing can be further increased. Therefore, even when the contact portion is small, that is, even when the size of the predetermined surface is small, the thickness of the conductive material after printing can be appropriately secured, and the contact portion at the time of contact with the fixed contact can be secured. Since the deterioration of the conductivity is suppressed, the detection of the switch operation becomes accurate. Therefore, the contact switch function can be accurately performed regardless of the size of the contact portion.

The movable contact body is a contact body made of a plurality of make-type elastic resins having a contact time difference and having a substantially circular contact part and a substantially arcuate contact part disposed on the outer peripheral side of the substantially circular contact part. There may be. In this case, the substantially circular contact portion is formed by printing the conductive material on a surface formed in a substantially circular dish shape, and the substantially arc-shaped contact portion is formed on a surface formed in an elongated groove shape. Preferably, the conductive material is formed by printing.

Although the size of the plural make type movable contact body tends to be small, the plural make type movable contact body is formed by forming the concave shape of the predetermined surface into a shape suitable for the shape of each contact portion. The contact switch function can be performed accurately.

The substantially circular contact portion and the substantially arc contact portion are:
It is easy to simultaneously form the predetermined surfaces and print the conductive material on the predetermined surfaces, and the manufacturing process can be simplified by integral molding.

In order to achieve the same object, the movable contact body according to the second aspect of the present invention has a structure according to the first aspect,
The predetermined surface before printing the conductive material,
After the conductive material is printed, the contact portion is formed in such a shape that no concave portion is formed on the surface of the contact portion facing the fixed contact.

With this configuration, the predetermined surface is formed in such a shape that no concave portion is formed on the surface of the contact portion facing the fixed contact after the conductive material is printed, so that the contact portion in contact with the fixed contact is formed. The contact surface can be formed as a flat surface or a gentle convex surface. As a result, it is possible to secure a contact area with the fixed contact and secure a good contact switch function.

According to a third aspect of the present invention, there is provided a movable contact body according to the second aspect of the present invention.
A flat portion (21a) is provided at a substantially central portion of the predetermined surface before printing the conductive material.

According to this configuration, since the flat portion is provided substantially at the center of the predetermined surface, a concave portion is formed on the contact surface of the contact portion that contacts the fixed contact, as compared with the case where the substantially central portion is largely recessed. It is hard to be done. Therefore, a good contact switch function can be ensured by securing the contact area with the fixed contact.

According to a fourth aspect of the present invention, there is provided a method of manufacturing a movable contact body according to the present invention, wherein the movable contact body is provided so as to face a fixed contact provided on a substrate, and to a predetermined surface facing the fixed contact. A method of manufacturing a movable contact body having a contact portion formed and performing a contact switch function by separating and contacting the fixed contact with the fixed contact, wherein the predetermined surface of the movable contact body is formed in a concave shape, The contact portion is formed by printing and solidifying a conductive fluid on the predetermined surface formed in the concave shape.

According to this configuration, the predetermined surface of the movable contact body is formed in a concave shape, and the conductive fluid is printed and solidified on the predetermined surface formed in the concave shape. The conductive fluid is filled, and the thickness of the conductive fluid after printing can be increased. Therefore, even when the contact portion is small, that is, even when the size of the predetermined surface is small, the thickness of the conductive fluid after printing can be appropriately secured, and the contact portion at the time of contact with the fixed contact can be secured. Is suppressed, the detection of the switch operation becomes accurate. Therefore, the contact switch function can be accurately performed regardless of the size of the contact portion.

[0019]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view of a movable contact body unit 10 according to an embodiment of the present invention as viewed obliquely from below.

The movable contact unit 10 includes a base 12
And the plurality of movable contact bodies 11 are integrally formed of an elastic resin or the like. The movable contact unit 10 is applied to, for example, a small keyboard device, and is formed in units of one octave. The movable contact body 11 is provided corresponding to each key of a keyboard (not shown).

FIG. 2 is an exploded perspective view of the switch section.
FIG. 1A shows the movable contact unit 10, and FIG. 1B shows the substrate 30. The switch unit includes the movable contact unit 10 and the substrate 30, and is formed by joining these. As shown in FIG. 2B, a fixed portion 31 is provided on the substrate 30 so as to correspond to each movable contact body 11. Each fixed part 31 includes a fixed contact 31a and two fixed contacts 31b.
, And each of the fixed contacts 31a and 31b is a contact pattern formed of a pair of opposing comb-shaped electrodes.

As shown in FIG. 1A, the movable contact body 11
Has a form that bulges above the base body 12, and an actuator contact portion 13 with which a key actuator (not shown) abuts is formed on the upper portion. As will be described later, when the actuator contact portion 13 is depressed due to key depression, the movable contact body 11 is crushed by elasticity, and a circular contact portion 20 and an arc-shaped contact portion 23 of the movable contact body 11 which will be described later are fixed contacts 31a. , 3
1b. Thereby, the fixed contacts 31a, 31b
Are electrically short-circuited and become conductive, and a key-pressing operation is detected.

FIG. 3 is a partial bottom view of the movable contact unit 10. As shown in FIG. FIG. 4 shows that the movable contact body unit 10
FIG. 3 is a partial cross-sectional view along the direction in which the movable contact bodies 11 are shown together with 0. FIG. 4A shows one movable contact body 11 and the fixed portion 31. However, each movable contact body 11 and the fixed portion 31 have the same configuration. FIGS. 4B and 4C are partially enlarged views of the circular contact portion 20 and the arc contact portion 23 shown in FIG.

As shown in FIG. 4A, the movable contact body 11 is bonded and fixed to the substrate 30 so as to face the surface of the substrate 30 on which the fixing portion 31 is provided. The movable contact body 11 is a so-called two-make contact body, and has a circular contact part 20 and an arc-shaped contact part 23. Since the movable contact body 11 has elasticity, the second skirt portion 15 bends with the key pressing operation, and the arc-shaped contact portion 23 can be displaced in the vertical direction. Similarly, the first skirt portion 14 bends and the circular contact portion is formed. 20 is vertically displaceable. Therefore, the arc-shaped contact portion 23,
The circular contact portion 20 comes into contact with the fixed portion 31. Circular contact 2
0 is a small size (for example, Φ2.5).

The circular contact portion 20 is a fixed contact 31
a, the arc-shaped contact portion 23 is opposed to the fixed contact 31b, and the respective contact portions 20, 23 are respectively fixed contact 31a, 31
b. The arc-shaped contact portion 23 and the fixed contact 31b constitute a first make switch, and the circular contact portion 20 and the fixed contact 31a constitute a second make switch.

As will be described later, the distal end (lower end) of the circular contact portion 20 and the arc-shaped contact portion 23 of the movable contact body 11 are
The conductive carbon inks 22 and 25 are printed (transferred), respectively (FIG. 3).
25 each contact contact surface 22a, 25a is a fixed contact 31
a, 31b, the fixed contacts 31a, 3b
Each pair of comb-shaped electrodes 1b is electrically short-circuited. Thus, each of the circular contact portions 20 and the arc-shaped contact portions 23 performs a contact switch function. Further, a key pressing speed or the like can be detected based on a time difference between ON of the first make switch and the second make switch.

The circular contact portion 20 is formed as follows.
First, the movable contact body 11 is integrally formed by a mold,
Before printing the carbon ink 22, a substantially circular dish-shaped concave surface 21 (predetermined surface) is formed at the ink printing end of the circular contact portion 20 (FIG. 4B). At this time, a flat portion 21a is provided substantially at the center of the concave surface 21. Such a shape is possible by setting the shape of the mold.

Next, the carbon ink 22 is applied to the concave surface 21.
Print. Specifically, the liquid carbon ink 22 is attached to a predetermined pin, the carbon ink 22 attached to the pin is printed on the concave surface 21, and the carbon ink 22 is solidified by heating and drying. Since the carbon ink 22 is filled in the recess formed by the concave surface 21, the thickness of the carbon ink 22 can be increased according to the depth of the recess of the concave surface 21.

When the flat portion 21a is not provided at all and the substantially central portion of the concave surface 21 is greatly depressed, the carbon ink 22
Solidifies when the carbon ink 22 contacts the contact surface 2
There is a possibility that a concave portion is formed in 2a. In the present embodiment,
Since the flat portion 21a is provided, the contact contact surface 22a is formed as a flat surface or a gentle convex surface, and an appropriate contact area with the fixed contact 31a is secured.

The depth of the concave surface 21 and the size of the flat portion 21 a are determined by considering various conditions such as the viscosity and concentration of the carbon ink 22 and the size of the circular contact portion 20.
An appropriate value may be set so that no concave portion is formed in 2a. It is not essential to provide the flat portion 21a as long as the formation of the concave portion on the contact contact surface 22a can be avoided. For example, instead of providing the flat portion 21a, the concave surface 21
May be appropriately set, for example, by increasing the radius of curvature only at the center. The shape of the curved surface can be freely set by designing the mold, and may be determined individually according to the specifications.

On the other hand, the arc-shaped contact portion 23 is formed in substantially the same manner as the circular contact portion 20. The lower end 14a of the wall extending downward from the first skirt 14 is formed in an annular shape surrounding the circular contact 20 (FIG. 3), but the arc-shaped contact 23 is formed in the outer circumferential direction 2 of the circular contact 20. This annular lower end 1
4a (FIGS. 3 and 4A) to improve switch detection accuracy.

Before printing the carbon ink 25, the ink printing end of the arc-shaped contact portion 23 (the portion corresponding to the carbon ink 25 at the lower end 14a shown in FIG. 3)
A groove-shaped surface 24 (predetermined surface) is provided (FIG. 4C).
Like the concave surface 21, the groove surface 24 has a concave cross section along the direction in which the movable contact members 11 are arranged, and the carbon ink 25 has a concave shape.
Is formed in the lower end portion 14a to be elongated over the entire length of the portion on which is printed. Further, a flat portion 24a is formed substantially at the center of the groove surface 24. The flat portion 24a is provided over the entire length of the grooved surface 24. The method of forming the grooved surface 24 and the flat portion 24a and the operation and effect thereof are similar to those of the circular contact portion 20.
Are the same as the concave surface 21 and the flat portion 21a. Therefore, the thickness of the carbon ink 25 can be increased by the groove-shaped surface 24. In addition, since a flat portion 24a hardly forms a concave portion on the contact contact surface 25a of the carbon ink 25, an appropriate contact area with the fixed contact 31b can be secured.

The concave surface 21 of the above-described carbon ink 22
And the carbon ink 25 are printed on the grooved surface 24 at the same time, so that both the circular contact portions 20 and the arc contact portions 23 are formed at the same time. Note that, depending on the size of the movable contact body 11, a concave end face such as the grooved face 24 may be provided on only one of these contact portions, for example, only the arc-shaped contact portion 23.

In order to facilitate the manufacture of the mold, the groove-shaped surface 24 is provided over the entire periphery of the lower end portion 14a, and the printing area of the carbon ink 25 is appropriately limited to an arc-shaped area so as to be arc-shaped. The contact portion 23 may be formed.
Further, the arrangement of the arc-shaped contact portions 23 is not limited to an arrangement of two locations in the outer peripheral direction.

According to the present embodiment, since the portion of the circular contact portion 20 where the carbon ink 22 is printed is formed on the concave surface 21, it is possible to secure an appropriate film thickness after printing the carbon ink 22. it can. Therefore, even if the circular contact portion 20 is small in size as in the present embodiment, the fixed contact 3
Since the deterioration of the conductivity of the circular contact portion 20 at the time of contact with the contact 1a is suppressed, it is possible to prevent a situation where the resistance value does not decrease to the threshold value and the switch is not detected from being turned on. Can be performed accurately. The same effect can be obtained with the groove-shaped surface 24 also for the arc-shaped contact portion 23.

A flat portion 21 is provided substantially at the center of the concave surface 21.
a, the concave portion facing the fixed contact 31a is less likely to be formed on the contact contact surface 22a after the solidification of the carbon ink 22, as compared with the case where the substantially central portion is simply largely concave. 22a is formed as a flat surface or a gentle convex surface. Therefore, a good contact switch function can be ensured by securing the contact area with the fixed contact 31a. As for the arc-shaped contact portion 23, since the flat portion 24a is provided substantially at the center of the groove-shaped surface 24, the same effect can be obtained.

Further, since the concave surface 21 and the groove surface 24 are integrally formed at the same time and the carbon inks 22 and 25 are simultaneously printed, the manufacturing process can be simplified.

The same applies to conductive fluids other than the carbon inks 22 and 25.

In the present embodiment, each of the contact portions 20,
Although the printing of the carbon inks 22 and 25 on the base 23 is performed via the pins, the printing may be performed by a dispenser method of directly injecting and printing the carbon inks 22 and 25 on the respective contact parts 20 and 23. .

[0041]

As described above, according to the first aspect of the present invention,
According to the movable contact body, the contact switch function can be accurately performed regardless of the size of the contact portion.

According to the movable contact body of claim 2 of the present invention,
A good contact switch function can be ensured by securing the contact area with the fixed contact.

According to the movable contact body of claim 3 of the present invention,
A good contact switch function can be ensured by securing the contact area with the fixed contact.

According to the method of manufacturing the movable contact body of the fourth aspect of the present invention, the contact switch function can be accurately performed regardless of the size of the contact portion.

[Brief description of the drawings]

FIG. 1 is a perspective view of a movable contact body unit according to an embodiment of the present invention as viewed obliquely from below.

FIG. 2 is an exploded perspective view of a switch unit.

FIG. 3 is a partial bottom view of the movable contact body unit.

FIG. 4 is a partial cross-sectional view along a direction in which the movable contact bodies are shown together with a movable contact body unit and a substrate.

[Explanation of symbols]

10 movable contact body unit, 11 movable contact body, 1
2 base body, 20 circular contact portions, 21 concave surface (predetermined surface), 21a flat portion, 22 carbon ink, 22a contact contact surface, 23 arc contact portion, 2
4 grooved surface (predetermined surface), 24a flat portion, 25
Carbon ink, 25a contact contact surface, 30 substrate, 31 fixing part, 31a fixed contact, 31b
Fixed contact

Claims (4)

[Claims] A predetermined surface (2) disposed opposite to a fixed contact (31) provided on a substrate and facing the fixed contact.
A movable contact body (11) having a contact portion (20) formed by printing a conductive material (22) on 1) and performing a contact switch function by separating and contacting the contact portion with the fixed contact.
The movable contact body, wherein the predetermined surface of the movable contact body before printing the conductive material is formed in a concave shape. 2. The method according to claim 1, wherein the predetermined surface before printing the conductive material is formed into a shape such that no recess is formed on a surface of the contact portion facing the fixed contact after the conductive material is printed. The movable contact body according to claim 1, wherein 3. The movable contact body according to claim 2, wherein a flat portion is provided at a substantially central portion of the predetermined surface before printing the conductive material. 4. A fixed contact provided on a substrate, comprising a contact portion formed on a predetermined surface facing the fixed contact, wherein the contact portion comes into contact with and separates from the fixed contact. A method for manufacturing a movable contact body that performs a contact switch function, wherein the predetermined surface of the movable contact body is formed in a concave shape, and a conductive fluid is printed and solidified on the predetermined surface formed in the concave shape. The method for manufacturing a movable contact body, wherein the contact part is formed by the method described above.