JP4252248B2 - Plane switch - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a plane switch used for an operation switch of an electronic device or the like, and in particular, a plane using a diaphragm made of metal or the like and devising the position of an air channel hole provided in a film covering the diaphragm. Regarding switches.
[0002]
[Prior art]
FIG. 3 is a diagram showing a conventional planar switch 20.
[0003]
3 (1) is a plan view of the planar switch 20, and FIG. 3 (2) is a diagram showing a cross section taken along the line IIIA-IIIB in FIG. 3 (1).
[0004]
In the conventional planar switch 20, a fixed side terminal 14 and a movable side terminal 15 that is separated from the fixed side terminal 14 are provided on one surface of the substrate 16.
[0005]
Further, the dome-shaped diaphragm 11 is flexible, and a fixed contact 12 that contacts the fixed terminal 14 is formed on the peripheral edge of the diaphragm 11, and a movable central portion on the concave side of the diaphragm 11 is movable. A movable contact 13 that can contact and detach from the side terminal 15 is formed, and the diaphragm 11 is placed on the substrate 16 so that the fixed contact 12 is always in contact with the fixed terminal 14.
[0006]
The holding film 27 is in contact with the diaphragms 11 and 16 and covers the entire surface of the diaphragm 11 and the substrate 16 existing around the peripheral edge of the diaphragm 11, and the direction of the diaphragm 11 along the surface of the 16 substrate (the right angle of the arrow AR21). The diaphragm 11 is held so as not to shift in the direction). In addition, the board | substrate 16 which is the single side | surface of the holding | maintenance film 27, and the surface by the side of the diaphragm 11 have adhesiveness.
[0007]
The holding film 27 is provided with a through hole 28. The through hole 28 overlaps a part of the outer peripheral edge of the diaphragm 11. That is, a part of the outer peripheral edge of the diaphragm 11 can be seen from the outside of the planar switch 20 through the through hole 28.
[0008]
When the planar switch 20 is pushed down in the direction of the arrow AR21, the diaphragm 11 is deformed so that the movable contact 13 approaches the movable terminal 15, and the volume of the space SP31 surrounded by the diaphragm 11 and the substrate 16 decreases. To do. Due to this decrease, the air pressure in the space SP31 increases. Due to the increase in air pressure, the air in the space SP31 leaks outside the planar switch 20 through the slight gap between the fixed contact 12 and the fixed terminal 14 and the through hole 28.
[0009]
Subsequently, when the depression is released, the diaphragm 11 is restored to the shape before the depression. When this restoration is performed, the volume of the space SP31 increases. Due to this increase, the air pressure in the space SP31 decreases, and air enters the space SP31 from the outside of the planar switch 20.
[0010]
FIG. 4 is a plan view showing a second conventional planar switch 30.
[0011]
The planar switch 30 is different from the planar switch 20 in that a slit 31 is provided instead of the through hole 28, and the other parts are configured in the same manner as the planar switch 20.
[0012]
[Problems to be solved by the invention]
By the way, in the conventional planar switch 20, when the depression is released, air enters the space SP31 inside the planar switch from the outside of the planar switch 20.
[0013]
At this time, fine dust contained in the air also enters at the same time, and enters the contact area between the fixed contact 12 and the fixed terminal 14, the surface of the movable terminal 15, and the surface of the movable contact 13. There is a risk of adhesion.
[0014]
The amount of fine dust adhering to the part where the fixed contact 12 and the fixed terminal 14 are in contact with each other, the surface of the movable terminal 15 and the surface of the movable contact 13 as the above-described operation of pressing down and releasing the pressing down is repeated. There is a problem that it becomes easy to cause poor contact.
[0015]
In the conventional planar switch 30, a slit 31 is provided in the vicinity of the outer peripheral edge of the diaphragm 11, and the sectional area of the slit 31 is smaller than that of the through hole 28 provided in the planar switch 20, and further enters from the slit 31. Since the fine dust is adsorbed to some extent by the adhesive part of the holding film 37, the amount of dust entering the inside of the flat switch 30 is reduced by the pressing and releasing operation per one time. Therefore, the flat switch 30 is less likely to cause contact failure than the flat switch 20.
[0016]
However, in the flat switch 30, the stress generated by the depression and release is easily concentrated on the end portion 31 </ b> A of the slit 31, and the slit provided in the holding film 37 is repeated by repeating the depression and depression release operations. There is a problem that cracks are likely to occur at the end 31A of 31.
[0017]
The present invention has been made in view of the above problems, and in particular, is a planar switch having a flexible dome-shaped diaphragm, and when the planar switch is pushed down and subsequently the pushing-down operation is released. In a planar switch having a film having a through hole for an air channel that keeps the air pressure in the planar switch constant, it is possible to effectively suppress the occurrence of contact failure when the depression and depression release operations are repeated. An object of the present invention is to provide a planar switch that can be used.
[0018]
[Means for Solving the Problems]
The invention of claim 1 includes a fixed-side terminal which is formed in an annular shape, and the movable terminal inwardly disposed away from the fixed side terminal of the fixed-side terminal provided on one surface The fixed side contact that is always in contact with the fixed side terminal and the fixed side terminal is formed at the peripheral portion, and the movable side contact that can be contacted and detached from the movable side terminal is formed at the substantially central portion of the concave side. Is in contact with the circular dome-shaped flexible diaphragm placed on the substrate, the diaphragm and the substrate so that the movable contact is separated from the movable terminal. covers and the substrate of the peripheral portion of the entire surface and the diaphragm of the diaphragm, retaining the film in which the diaphragm so as not shifted in the direction along the surface of the substrate, held by the adhesive between the substrate and the diaphragm The air that is provided in the holding film and is present at a position slightly away from the periphery of the diaphragm and that is present in the space surrounded by the substrate and the diaphragm passes through the diaphragm according to deformation of the diaphragm. It is a planar switch having a through-hole having a circular shape, an ellipse, a shape in which four corners of a square are formed by an arc, and a circular through-hole having a shape in which a circular hole is penetrated at the end of a slit. .
[0019]
The invention described in claim 2 is the planar switch according to claim 1, wherein the through hole has a circular shape, and the diameter of the circle is between 0.05 mm and 2 mm.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a diagram showing a configuration of a planar switch 10 according to an embodiment of the present invention.
[0021]
FIG. 1 (1) is a plan view of the planar switch 10, and FIG. 1 (2) is a diagram showing a cross section taken along line IA-IB in FIG. 1 (1).
[0022]
The planar switch 10 includes a substrate 16, a planar switch 11 placed on the substrate 16, and a holding film 17 that covers and holds the planar switch 11 and the substrate 16.
[0023]
Here, the substrate 16 includes, as two switching circuit terminals, an annular fixed side terminal 14 and a movable side terminal 15 disposed near the center of the fixed side terminal 14 and separated from the fixed side terminal 14. Provided on one side of the substrate 16.
[0024]
Further, the diaphragm 11 formed in a dome shape by a thin plate of a substantially disk-like metal has flexibility, and a fixed-side contact 12 that is in contact with the fixed-side terminal 14 is formed on the periphery of the diaphragm 11. The movable side contact 13 that can be brought into contact with and detached from the movable side terminal 15 is formed in the substantially central portion of the concave side of the diaphragm 11, and the diaphragm 11 has the fixed side contact 12 always in contact with the fixed side terminal 14. The diaphragm 11 is placed on the substrate 16 with the face down. Note that the movable terminal 15 and the movable contact 13 are separated from each other in a normal state (a state where the planar switch 10 is not pushed down).
[0025]
The holding film 17 is in contact with the diaphragms 11 and 16 and covers the entire surface of the diaphragm 11 and the substrate 16 existing around the periphery of the diaphragm 11, and the direction of the diaphragm 11 along the surface of the substrate 16 (at right angles to the arrow AR21). The diaphragm 11 is held so as not to shift in the direction). In addition, the board | substrate 16 which is the single side | surface of the holding | maintenance film 27, and the surface by the side of the diaphragm 11 have adhesiveness.
[0026]
In addition, air that exists in the space surrounded (enclosed) by the substrate 16 and the diaphragm 11 passes through the holding film 17 in accordance with the deformation of the diaphragm due to the pressing and releasing of the planar switch 10. A through hole 18 is provided.
[0027]
Further, the through hole 18 is provided so as to exist at a position slightly away from the periphery of the diaphragm 11. That is, the through hole 18 and the peripheral edge of the diaphragm 11 do not interfere with each other.
[0028]
The through hole 18 is formed by punching and has a circular shape, that is, a shape in which a cross section perpendicular to the axis of the through hole 18 is circular. The diameter of the through hole 18 is about 1 mm.
[0029]
A plurality of, for example, eight through-holes 18 are provided, and each of these eight through-holes 18 exists at a position slightly separated from the peripheral edge of the diaphragm 11 (a position not overlapping with the diaphragm), and the center of the diaphragm 11 Are present at positions equally distributed (arranged at equal intervals) on the circumference of the pitch circle drawn with a predetermined radius.
[0030]
The shortest distance L11 between the peripheral edge of the through hole 18 and the outer peripheral edge of the diaphragm 11 is about 1 mm.
[0031]
Next, a description will be given of the operation of the planar switch 10 when it is pushed down and subsequently released.
[0032]
FIG. 2A is a sectional view showing a state in which the planar switch 10 is being pushed down, and FIG. 2B is a sectional view showing a state in which the pushing is finished.
[0033]
In the state shown in FIG. 1B (the state before the plane switch 10 is pushed down), the plane switch 10 is pushed down in the direction of the arrow AR11. By this depression, the diaphragm 11 and the holding film 17 are deformed as shown in FIG. 2A, and the movable contact 13 approaches the movable terminal 15.
[0034]
In this state, when the planar switch 10 is further pushed down in the direction of the arrow AR11, the diaphragm 11 and the holding film 17 are further deformed, and the movable contact 13 is moved to the movable terminal 15 as shown in FIG. The fixed side terminal 14 and the movable side terminal 15 are electrically connected to each other. In this state, the pressing operation of the planar switch 10 is finished.
[0035]
During the pressing operation, the volume of the space SP11 surrounded by the diaphragm 11 and the substrate 16 is reduced according to the amount of the diaphragm 11 being crushed, and the air pressure in the space SP11 increases due to this reduction. .
[0036]
Then, the air in the space SP11 has a slight gap between the fixed contact 12 and the fixed terminal 14, a slight gap between the holding film 17 and the substrate 16, and the through hole 18. It is discharged out of the planar switch 10 through.
[0037]
Next, as shown in FIG. 2 (2), when the depression is released in the state where the depression is completed, the diaphragm 11 passes through the state shown in FIG. 2 (1) by the elasticity of the diaphragm 11. Thus, the original state shown in FIG.
[0038]
During the restoration operation, the volume of the space SP11 surrounded by the diaphragm 11 and the substrate 16 increases according to the restoration amount of the diaphragm 11, and the air pressure in the space SP11 decreases due to this increase.
[0039]
Then, the air passes through the through hole 18, the clearance slightly existing between the holding film 17 and the substrate 16, and the clearance slightly existing between the fixed side contact 12 and the fixed side terminal 14. It enters the planar switch 10 from the outside of the switch 10.
[0040]
In addition, with the inflow of air into the flat switch 10, fine dust existing in the air may also enter the flat switch 10.
[0041]
According to the planar switch 10, the through hole 18 is only slightly separated from the outer peripheral edge of the diaphragm 11 (the distance L11 shown in FIG. 1 (1) is about 1 mm). Air smoothly flows into the SP 11 (into the planar switch 10), and a smooth restoration operation is performed.
[0042]
Further, according to the planar switch 10, fine dust may enter the space SP <b> 11 together with the air when performing the restoration operation, but the through hole 18 is slightly separated from the outer peripheral edge of the diaphragm 11. Therefore, the fine dust must pass through a slight gap existing between the substrate 16 and the holding film 17, and when passing through this gap, the surface of the holding film 17 having adhesiveness (the substrate) The fine dust is captured on the surface 16 side).
[0043]
Therefore, the amount of dust entering the flat switch 10 by one restoration operation is smaller than in the past, and fine dust adhering to the fixed side contact 12, the movable side contact 13, the fixed side terminal 14, and the movable side terminal 15 is reduced. This amount is also smaller than before.
[0044]
Further, even if the operation of depressing the planar switch 10 and subsequently releasing the depression is repeated, the contact failure is less likely to occur than, for example, the conventional planar switch 20.
[0045]
Further, since the shape of the through-hole 18 is circular, stress concentration due to the operation such as pressing down is unlikely to occur at the periphery of the through-hole 18, and even if the operation of releasing the pressing after the pressing down is repeated, Less likely to crack at the periphery.
[0046]
In the planar switch 10, a metal diaphragm is used, but a member having conductivity and elasticity, such as a conductive plastic, may be used.
[0047]
Further, in the planar switch 10, the diameter of the through hole 18 is about 1 mm, but the diameter of the through hole can be set within a range of 0.05 mm to 2 mm, for example.
[0048]
Further, in the planar switch 10, the shortest distance L11 between the peripheral edge of the through hole 18 and the outer peripheral edge of the diaphragm 11 is about 1 mm. However, the shortest distance L11 is set to a value of, for example, more than 0 mm and 2 mm or less. Good.
[0049]
In the planar switch 10, the through hole 18 is formed by punching, but it may be formed by using at least one of punching, drilling, and processing using a needle.
[0050]
Further, in the planar switch 10, the number of the through holes 18 is eight, but it is sufficient that at least one through hole is provided. Moreover, it is not necessary to provide a through-hole at equal intervals.
[0051]
Further, in the planar switch 10, the shape of the through hole is circular, but the shape of the ellipse, ellipse, and quadrilateral is formed by arcs, and the circular hole is penetrated at the end 31A of the slit 31 shown in FIG. A through-hole having a shape other than a circle, such as a shaped shape, that is less likely to cause stress concentration at the periphery of the through-hole may be employed.
[0052]
Further, in the planar switch 10, the outer shape of the diaphragm 11 is circular, but a shape that can exhibit the function of the diaphragm, such as an ellipse or an ellipse, may be employed.
[0053]
【The invention's effect】
According to the present invention, there is provided a planar switch having a flexible dome-shaped diaphragm, and the air pressure in the planar switch is kept constant when the planar switch is depressed and subsequently released. In a planar switch having a film having a through hole for a channel, when the above-described depression and depression release operations are repeated, the occurrence of contact failure can be effectively suppressed.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a configuration of a planar switch according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view showing a state in which a planar switch is pushed down.
FIG. 3 is a diagram showing a conventional planar switch.
FIG. 4 is a plan view showing a second conventional planar switch.
[Explanation of symbols]
10 ... Planar switch,
11 ... Diaphragm,
12: Fixed side contact,
13 ... movable side contact,
14: Fixed terminal,
15 ... movable terminal,
16 ... substrate,
17 ... holding film,
18 ... through hole.

Claims (2)

A fixed side terminal which is formed in an annular shape, and the substrate and the movable terminal inwardly disposed away from the fixed side terminal of the fixed-side terminal is provided on one surface;
A stationary contact that is always in contact with the stationary terminal is formed at the peripheral portion, and a movable contact that can be contacted and detached from the movable terminal is formed at a substantially central portion on the concave side. A circular dome-shaped flexible diaphragm placed on the substrate such that is in a state of being separated from the movable terminal;
Covers and the substrate of the peripheral portion of the entire surface and the diaphragm of the diaphragm in contact with the said diaphragm and the substrate, so that the diaphragm is not displaced in the direction along the surface of the substrate, the adhesive and the substrate and the diaphragm a holding film is held by;
Penetration through which air that is provided in the holding film and exists in a position slightly separated from the periphery of the diaphragm and that is surrounded by the substrate and the diaphragm passes through according to deformation of the diaphragm a hole, circular, elliptical, shape forming a square corner arc, and the through hole of the circular shape is a shape obtained by penetrating a circular hole at the end of the slit;
A flat switch characterized by comprising: In claim 1,
A planar switch characterized in that the shape of the through hole is circular, and the diameter of the circle is between 0.05 mm and 2 mm.

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