JP2016051657A - Push switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a push switch that can suppress occurrence of exfoliation of a sheet for sealing a movable member and a press member as compared with a case where the construction of the present invention is not provided.SOLUTION: A push switch (1, 2) has a case (10, 11) having a recess portion, first and second fixed contacts (14, 12) disposed on the bottom surface of the recess portion, a movable member (20) which has a convex type dome-like shape, is disposed on the bottom surface so that the end portion thereof is brought into contact with the first fixed contact, and pressed so that the dome-shape is reversed, whereby the first and second fixed contacts are conducted to each other, a first sheet (30) for encapsulating the movable member in the recess portion, press members (40, 45) disposed at the upper portion of the first sheet to press the movable member, a second sheet (50) which covers the press member and fixes the press member in cooperation with the first sheet, and an air hole (62) through which the space between the first sheet and the second sheet intercommunicates with the outside.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a push switch.

  A push switch is known as a button switch used in an electronic device such as a mobile phone or an audio device. In such an electronic device, a push switch having a protrusion at an operation location is widely used. For example, in Patent Document 1, a case made of molded resin having a recess, a first fixed contact and a second fixed contact exposed and fixed in the recess, and the fixed contacts disposed in the recess are operated. A push switch is described that includes a movable contact that conducts the light and a protective sheet that is attached to the case so as to cover the recess. In this push switch, the protrusion member is fixed by welding to the upper surface or the lower surface position of the protective sheet corresponding to the central portion of the movable contact, and the portion is formed as an operation protrusion.

  Further, in Patent Document 2, a first fixed contact formed on a substrate, a substantially annular second fixed contact disposed so as to surround the first fixed contact, and a second fixed contact are connected. The dome-shaped movable contact provided and a fixing sheet that positions and holds the movable contact by covering the movable contact, and air inside the movable contact is obtained so that a good click feeling can be obtained when pressed. A dome-shaped switch provided with an air hole for escape is described.

JP 2012-059432 A JP-A-2005-166609

  If a pressing member as an operation protrusion is provided on the sheet enclosing the movable member, the pressing member may be peeled off the sheet by repeated external impacts or pressing operations. Therefore, in order to prevent peeling of the pressing member, the pressing member is arranged on the sheet enclosing the movable member, and the pressing member is covered and fixed with another sheet so that the sheet has a double structure. It is possible.

  However, particularly when the pressing member is a thick member, a space is formed between the upper sheet and the lower sheet having a double structure. Since the air accumulated in this space greatly expands in the reflow process when the push switch is mounted, there is a problem in that the pressing member is peeled off from the switch body together with the lower sheet. If the sheet is peeled off in this manner, waterproofing cannot be maintained, and the push switch becomes a defective product.

  Therefore, an object of the present invention is to provide a push switch that suppresses the occurrence of peeling of the sheet enclosing the movable member and the pressing member, as compared with the case without this configuration.

  The push switch according to the present invention has a case having a recess, first and second fixed contacts disposed on the bottom surface of the recess, a convex dome shape, and an end thereof is in contact with the first fixed contact. The movable member which is arranged on the bottom surface and reverses the shape of the dome when pressed and makes the first and second fixed contacts conductive with each other, the first sheet which encloses the movable member in the recess, and the movable In order to press the member, a pressing member disposed on the upper part of the first sheet, a second sheet that covers the pressing member and fixes the pressing member in cooperation with the first sheet, and the first sheet And an air hole for communicating the space between the second sheet and the second sheet to the outside.

The push switch further includes an adhesive sheet that adheres the first sheet and the second sheet except for a part of the outer peripheral portion at the outer peripheral portion of the first sheet, and the air holes are bonded by the adhesive sheet. It is preferable that the gap is formed by a gap between the first sheet and the second sheet in a part of the outer peripheral portion that is not formed.
In the above push switch, it is preferable that the adhesive sheet extends from the side wall of the case to the inner periphery of the recess to bond the first sheet and the second sheet.
In the above push switch, the adhesive sheet preferably has a thickness of 20 μm or more and 50 μm or less.
In the above push switch, it is preferable that at least a part of the upper surface and the side surface of the pressing member is fixed in contact with the second sheet.

  According to said push switch, compared with the case where this structure is not provided, it becomes possible to suppress generation | occurrence | production of peeling of the sheet | seat which encloses a movable member, and a pressing member.

1 is a perspective view of a push switch 1. FIG. FIG. 3 is an exploded perspective view of the push switch 1. 2 is a top view of the push switch 1. FIG. 2 is a bottom view of the push switch 1. FIG. FIG. 2 is a cross-sectional view of the push switch 1 along the line AA. 3 is a top view of an adhesive sheet 60. FIG. It is sectional drawing of the push switch 2 similar to FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, it should be understood that the present invention is not limited to the drawings or the embodiments described below.

  1 to 5 are a perspective view, an exploded perspective view, a top view, a bottom view, and a cross-sectional view taken along line AA of FIG. The push switch 1 includes a substrate 10, a mold frame 11, a tact spring 20, a lower sheet 30, a pressing member 40, an upper sheet 50, and an adhesive sheet 60 as main components. The push switch 1 is a tact switch in which a protruding portion by a pressing member 40 is attached to an operation location, and has a size of 4 mm × 3 mm on a plane and 1 mm in height, for example.

  As shown in FIG. 2, a central contact 12 and an outer contact 14 are formed on the upper surface of the substrate 10. The mold frame 11 is a rectangular frame-shaped member formed in accordance with the size of the substrate 10 and is bonded to the upper surface of the substrate 10 via an adhesive sheet (not shown). However, instead of bonding the substrate 10 and the mold frame 11 to each other, the substrate 10 and the mold frame 11 may be integrally formed by insert molding. The substrate 10 and the mold frame 11 function as a case of the push switch 1 and form a recess 16 in which the tact spring 20 is accommodated.

  The outer contact 14 and the center contact 12 are examples of first and second fixed contacts disposed on the bottom surface of the recess 16, respectively. The center contact 12 is a conductor having a square plane, and is disposed at the center of the surface of the substrate 10. The outer contact 14 is a conductor having a frame-like plane, and is disposed on the surface of the substrate 10 along the inner wall 17 of the mold frame 11 so as to surround the central contact 12.

  As shown in FIG. 4, electrodes 13a, 13b, 15a, 15b for connecting the push switch 1 to an external device are formed on the back surface of the substrate 10. The electrodes 13a and 13b are electrically connected to the central contact 12 via a through electrode and a back surface wiring (not shown). The electrodes 15a and 15b are electrically connected to the outer contact 14 via a through electrode and a back surface wiring (not shown). In addition, an insulating sheet material formed of an insulating synthetic resin is disposed on the back surface of the substrate 10.

  The tact spring 20 is an example of a movable member, and is formed of, for example, stainless steel. As shown in FIGS. 2 and 5, the tact spring 20 has a convex dome shape, and is disposed on the bottom surface of the concave portion 16 (that is, on the substrate 10) so that the end thereof is in contact with the outer contact 14. When the tact spring 20 is pressed with an operation load applied, the tact spring 20 is deformed so that the dome-shaped curve is crushed, and at least a part of the shape is inverted to contact the central contact 12. As a result, the central contact 12 and the outer contact 14 become conductive, and the switch is turned on. Further, the tact spring 20 is restored to its original dome shape when the operation load is lost. As a result, the central contact 12 and the outer contact 14 do not conduct and the switch is turned off. Only the center part of the tact spring 20 may be deformed into a concave shape, or the tact spring 20 may be deformed into a concave shape as a whole.

  The lower sheet 30 is a flexible insulating resin sheet, and the end of the back surface is bonded to the upper surface of the mold frame 11. The lower sheet 30 is an example of a first sheet, and encloses (seals) the tact spring 20 in the recess 16 together with the substrate 10 and the mold frame 11.

  The pressing member 40 is a resin member (dubbed) having a cylindrical shape, and is disposed on the lower sheet 30 as shown in FIG. The pressing member 40 functions to transmit the pressing force to the tact spring 20 when a pusher (not shown) is pressed. The pressing member 40 has a relatively large thickness, for example, about half the thickness of the push switch 1 as a whole.

  The upper sheet 50 is also a flexible insulating resin sheet similar to the lower sheet 30, and the back end of the upper sheet 50 is bonded to the lower sheet 30 via the adhesive sheet 60 on the upper surface of the mold frame 11. The upper sheet 50 is an example of a second sheet. The upper sheet 50 covers the pressing member 40 and has an end bonded to the lower sheet 30, thereby fixing the pressing member 40 in cooperation with the lower sheet 30.

  FIG. 6 is a top view of the adhesive sheet 60. The adhesive sheet 60 has a size that matches the substrate 10 and the mold frame 11, and a center portion is cut out along the inner wall 17 of the recess 16. Thereby, the adhesive sheet 60 adheres the lower sheet 30 and the upper sheet 50 at the outer peripheral portion of the lower sheet 30. Further, a part 61 of the outer peripheral portion of the adhesive sheet 60 is also cut off, and this portion 61 is a non-adhesive portion between the lower sheet 30 and the upper sheet 50. Therefore, the adhesive sheet 60 adheres the lower sheet 30 and the upper sheet 50 at the outer peripheral portion of the lower sheet 30 except for a part 61 of the outer peripheral portion.

  A gap is formed between the lower sheet 30 and the upper sheet 50 by such a non-adhesive portion. In the push switch 1, this gap becomes an air hole 62 that communicates the space 55 between the lower sheet 30 and the upper sheet 50 to the outside. That is, the air hole 62 is formed by a gap between the lower sheet 30 and the upper sheet 50 in a part 61 of the outer peripheral portion that is not bonded by the adhesive sheet 60.

  The air hole 62 functions as an escape passage (vent) for releasing the air between the lower seat 30 and the upper seat 50 to the outside when the pressure in the space 55 is increased. Thus, by providing a vent structure between the upper sheet 50 and the lower sheet 30, even if the air in the space 55 expands during reflow mounting, the air can be released to the air. For this reason, it becomes possible to suppress the occurrence of the phenomenon that the pressing member 40 is peeled off from the switch body together with the lower sheet 30. Furthermore, if such peeling is prevented, the concave portion 16 formed by the substrate 10 and the mold frame 11 is sealed by the lower sheet 30, so that the waterproof structure of the push switch 1 is maintained even after reflow mounting.

  The air holes 62 do not have to be formed by intentionally perforating the upper sheet 50, and can be formed as a non-adhesive portion between the lower sheet 30 and the upper sheet 50 as described above. The number of the air holes 62 may be any number. However, when the pressure in the space 55 is increased, the air in the space 55 only needs to escape to the outside. Further, the size of the air hole 62 may be about 1/8 of the length of one side of the adhesive sheet 60, for example. If the width of the air hole 62 is too large, the adhesive strength between the lower sheet 30 and the upper sheet 50 is reduced, and if it is too small, an air escape path is not secured. It is preferably about ˜20%.

  Further, in the push switch 1 having a large thickness of the pressing member 40 and a double structure of the lower sheet 30 and the upper sheet 50, when the pressing member 40 is pressed, the shape of the tact spring 20 is reversed from the start of pressing. The moving distance of the pressing member 40 until the switch is turned on is relatively long. For this reason, when the pressing member 40 is pressed, abnormal noise may occur due to the upper sheet 50 being swung.

  Therefore, it is preferable that a region where the upper sheet 50 and the lower sheet 30 are bonded is widened toward the center of the concave portion 16 to reduce a portion where the upper sheet 50 is twisted. That is, it is preferable that the adhesive sheet 60 extends from the upper surface of the mold frame 11 to the inner periphery of the recess 16 to bond the lower sheet 30 and the upper sheet 50. For example, as shown in FIG. 6, the width L2 of the adhesive sheet 60 is increased about 1.5 times toward the center of the mold frame 11 with respect to the thickness L1 between the inner wall 17 and the outer wall 18 of the mold frame 11. Good. When an evaluation test for subjective noise was performed on the push switch 1 having a side of about several mm, the width L2 of the adhesive sheet 60 was set to about 0.6 mm when the width L1 of the mold frame 11 was 0.4 mm. Then, it was confirmed that the generation of abnormal noise due to the wobbling of the upper sheet 50 was prevented. In other words, it has been confirmed that by making the adhesive area of the adhesive sheet 60 about 1.5 times the area of the upper surface of the mold frame 11, it is effective in preventing the generation of abnormal noise.

  Further, as shown in FIG. 5, it is preferable that the upper sheet 50 is bonded not only to the upper surface of the pressing member 40 but also to the side surface 41 to fix the pressing member 40. That is, it is preferable that at least a part of the upper surface and the side surface of the pressing member 40 is fixed in contact with the upper sheet 50. Thereby, since the part which the upper sheet | seat 50 twists further decreases, generation | occurrence | production of abnormal noise is prevented more reliably.

  In addition, the adhesive sheet 60 is preferably too thin if it is too thin, because the adhesive strength is weak, and depending on the location, the adhesive sheet 60 may not be fully adhered, causing abnormal noise during operation. When the thickness of the adhesive sheet 60 in the push switch 1 was changed and an evaluation test for the presence or absence of abnormal noise was performed, when the thickness was 10 μm, abnormal noise was generated due to the kinking of the upper sheet 50. It was confirmed that when the size was increased to about 20 μm to 50 μm, this abnormal noise was not generated. Therefore, from the viewpoint of preventing abnormal noise, the adhesive sheet 60 preferably has a thickness of 20 μm or more and 50 μm or less.

  FIG. 7 is a cross-sectional view of the push switch 2 similar to FIG. The push switch 2 shown in FIG. 7 is different from the push switch 1 of FIGS. 1 to 5 only in that a second pressing member 45 is attached to the bottom surface of the pressing member 40. The same components as those of the push switch 1 are denoted by the same reference numerals, and redundant description is omitted.

  The second pressing member 45 is a hemispherical resin member bonded to the bottom surface of the pressing member 40 and having a smaller diameter than the pressing member 40. In the push switch 2, the pressing member 40 and the second pressing member 45 are fixed between the lower sheet 30 and the upper sheet 50. Thus, by providing the second pressing member 45 and reducing the area of the contact point with the tact spring 20, the click feeling when the user operates the switch is improved.

  Similarly to the push switch 1, the push switch 2 is provided with a non-adhesive portion between the lower sheet 30 and the upper sheet 50 to form the air holes 62, so that the lower sheet 30 and the like can be peeled off during reflow. Occurrence is suppressed. Also in the push switch 2, the region where the upper sheet 50 and the lower sheet 30 are bonded is expanded toward the center of the recess 16, or at least a part of the upper surface and side surface of the pressing member 40 (reference numeral 41 in FIG. 7). The upper sheet 50 may be fixed, or the thickness of the adhesive sheet 60 may be increased to about 20 μm to 50 μm. Thereby, also in the push switch 2, the part which the upper sheet | seat 50 is twisted decreases, and generation | occurrence | production of the noise by the twist of the upper sheet | seat 50 is prevented.

DESCRIPTION OF SYMBOLS 1, 2 Push switch 10 Board | substrate 11 Mold frame 12 Center contact 14 Outer contact 16 Recessed part 20 Tact spring 30 Lower sheet 40 Pressing member 50 Upper sheet 60 Adhesive sheet 62 Air hole

Claims (5)

A case having a recess;
First and second fixed contacts disposed on the bottom surface of the recess;
The first and second fixed contacts have a convex dome shape, are arranged on the bottom surface so that the end portions thereof are in contact with the first fixed contact, and the dome shape is reversed when pressed. Movable members that conduct each other;
A first sheet enclosing the movable member in the recess;
A pressing member disposed on top of the first sheet to press down the movable member;
A second sheet covering the pressing member and fixing the pressing member in cooperation with the first sheet;
An air hole communicating the space between the first sheet and the second sheet to the outside;
A push switch characterized by comprising: An adhesive sheet that adheres the first sheet and the second sheet except for a part of the outer peripheral part in the outer peripheral part of the first sheet;
2. The push switch according to claim 1, wherein the air hole is formed by a gap between the first sheet and the second sheet in a part of the outer peripheral portion that is not bonded by the adhesive sheet.   3. The push switch according to claim 2, wherein the adhesive sheet extends from a side wall of the case to an inner periphery of the recess to bond the first sheet and the second sheet.   The push switch according to claim 2 or 3, wherein the adhesive sheet has a thickness of 20 µm or more and 50 µm or less.   The push switch according to any one of claims 1 to 4, wherein at least a part of an upper surface and a side surface of the pressing member is fixed in contact with the second sheet.

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