JP2005135789A - Key top of push switch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a key top having a circuit board with water tight structure, not requiring high precision molding of a case and a cover, which can be assembled easily. <P>SOLUTION: On the key top of the push switch, comprising an insulation sheet on which at least two wiring patterns to be connected to each other are formed, and a switch formed on the insulation sheet connecting the wiring patterns to each other by being pushed, constructed by pinching the insulation sheet including the switch, at least one face of the insulation sheet including the switch is water tightly covered by an insulation film. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a key top of a push switch, and more particularly to an improvement of a key top provided on a waterproof panel.

  Examples of the prior art in which the key top has a waterproof structure include the following.

JP 10-304479 A Japanese Utility Model Publication No. 7-25529

  FIG. 3 is a cross-sectional view of the main part of the “remote controller with an open / close lid” 1 disclosed in Patent Document 1. This conventional example will be briefly described. In FIG. 3, a spherical click spring type push switch 11 is mounted on the printed wiring board 10 in the casing 2 at a position corresponding to the key tops 6 and 7, and a switch type hole for detecting lid opening / closing is located near the upper edge. IC12 is arranged. The key tops 5 and 6 are respectively attached to the holes of the casing 2 and the lid 4, and resin sheets 8 and 9 are adhered to the entire surface.

FIG. 4 is a cross-sectional view of a “key top of a push switch” disclosed in Patent Document 2.
This conventional example will be briefly described.
FIG. 4 shows a casing 31 of an electronic device having a waterproof structure. A panel 33 for placing operation switches is placed on the opening of the main body 32 of the casing 31.

  A boss 34 is provided on the inner surface of the panel 33, and a substrate 35 is attached to the boss 34. A push switch 36 is provided on the panel 33 side of the substrate 35 located inside the housing 31. A key hole 38 is formed in a portion of the panel 33 facing the push switch 36 in order to provide a key top 37 for operating the push switch 36.

  A waterproof sheet 39 is overlaid on the panel 33. The waterproof sheet 39 is integrally provided with a protrusion as a key top 37 at a portion corresponding to the key hole 38 of the panel 33. The protrusion has a pressing portion 40 that protrudes inside the key hole 38 and presses the push switch 36, and an operation portion 41 that protrudes outward and is operated by a finger.

  An exterior panel 42 is overlaid on the waterproof sheet 39, and an operation portion 41 of the key top 37 projects from the key hole 43 provided corresponding to the shape of the waterproof sheet 39 on the exterior panel 42. . The main body 32, the panel 33, and the exterior panel 42 are integrally fixed by fixing means such as screws.

  FIG. 5 shows another conventional example, which is used for an electronic device having a waterproof structure, similarly to the conventional example shown in FIGS. In FIG. 5, reference numeral 50 denotes a key case having a recess 51. An insulating sheet 52 (for example, a circuit board made of PCB) is stored in the recess 51 of the key case. For example, a plurality of metal dome type switches 53 are soldered to the surface of the insulating sheet 52.

  54 is a key top made of a molded product of rubber and is arranged so as to cover the insulating sheet 52. A plurality of projections 55 are formed on the key top 54 at positions corresponding to the plurality of switches 53 described above. A key cover 56 is disposed so as to cover the key top 54, and a plurality of holes 57 are formed at positions corresponding to the plurality of protrusions 55 formed on the key top 54.

  These parts are arranged such that the key top protrusion faces the switch 53, the holes of the key cover 56 face each other so that the protrusion protrudes, and the PCB circuit board 52 is tightened by screws 58 so as to be watertight.

However, the push switch described above has the following problems.
In order to sandwich the key top made of rubber between the case and cover so that the insulation sheet (PCB circuit board) is not flooded, it is necessary to compress and seal it using the elasticity of the rubber. It is necessary to fit so that there is no. For that purpose, tightening with screws etc. from the back.
In order to prevent water from entering, it is necessary to fit the case and the cover so that the gap is minimized. Therefore, the case and cover which are plastic molded products require high accuracy.

  Therefore, the problem to be solved by the present invention is to realize a key top in which the insulating sheet itself has a watertight structure and the case and the cover do not require highly accurate molding.

In order to achieve such a problem, the invention according to claim 1 of the present invention is:
An insulating sheet on which at least two wiring patterns to be connected are formed, a switch that is formed on the insulating sheet and connects the wiring patterns by pressing, and an insulating sheet including the switch is sandwiched between the insulating sheet and the insulating sheet. On the key top of the push switch
By covering at least one surface of the insulating sheet including the switch with an insulating film in a watertight manner, there is no fear of a short circuit or corrosion even if water enters the key case and the key cover.

The invention according to claim 2 is the key top of the push switch according to claim 1,
Since an adhesive is used when water-tightly covering at least one surface of the insulating sheet including the switch with an insulating film, the configuration is simple.

The invention according to claim 3 is the key top of the push switch according to claim 1,
Since the insulating sheet is disposed between the key case and the key top, and the key case and the key cover are fitted and fixed, the structure is simple and the assembly is easy.

The present invention has the following effects.
According to the first to third aspects of the present invention, since at least one side of the key sheet including the switch is watertightly covered with the insulating film, even if water enters the key case and the key cover, there is a risk of short circuit or corrosion. Absent.

  Adhesive is used when water-tightly covering at least one side of the key sheet including the switch with an insulating film. The key sheet is disposed between the key case and the key top, and the key case and the key cover are fitted and fixed. The structure is simple and the assembly is easy. Therefore, it is not necessary to tighten the screw strongly in order to prevent the intrusion of water as in the prior art.

  Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view showing an arrangement state of a key top of a push switch according to the present invention, and FIG. 2 shows a main part of a key sheet (an assembly part of an insulating sheet 60, a switch 61 and an insulating film 62) used in the present invention. It is a perspective view.

  In FIG. 1, reference numeral 50a denotes a rectangular key case, and a wiring take-out hole 50b is formed at one end. 52a is a key sheet made of a rectangular insulating member and having a flexible wiring 52b at one end. The flexible wiring 52b is introduced into the instrument from the wiring extraction hole 50b of the key case 50a.

  FIG. 2 is a partially enlarged perspective view of the key sheet 52a. As shown in the drawing, a pattern A and a pattern B printed with, for example, a silver paste or the like are formed on one surface of the insulating sheet 60 in a non-contact state. That is, the end portion of the pattern B is formed in a U shape, and one end of the pattern A is in the vicinity of the center of the U portion.

  Reference numeral 61 denotes a metal dome that functions as a switch, in which a central portion of a thin plate formed in a cross shape is processed into a shape that rises into a dome shape. This metal dome is fixed in a state where the end of the cross portion is in contact with the U-shaped portion of the pattern B. And the pattern A and B will be in a conduction | electrical_connection state by pressing and denting a dome part.

  Reference numeral 62 denotes an insulating film formed in the same shape as the insulating sheet 60, which covers the insulating sheet 60 from above the switch 61 and is watertightly bonded with an adhesive or the like.

Returning to FIG. 1, reference numeral 54a denotes a key top in which an elastic protrusion 55a is formed at a position facing the switch 52 of the key sheet 52a, and is arranged so as to cover the key sheet 52a.
Reference numeral 56a denotes a key cover, and a hole 57a is formed at a position facing the protrusion 55a formed on the key top 54a.

  The key case 50a, the key sheet 52a, the key top 54a, and the key cover 56a are arranged in the order shown in FIG. 1, and the key case 50a is fitted and fixed to the edge portion 56b of the key cover 56a. When the projection 55a protruding from the hole 57a of the key cover 56a is pressed, the dome of the switch 52c is recessed and the patterns A and B are conducted as described above.

  According to the above configuration, since the key sheet itself has a watertight structure, even if liquid such as water enters through the key cover 56a or the key top 54a, an accident such as circuit corrosion or poor contact is prevented. can do. Therefore, it is not necessary to seal by tightening the screws, and it is not necessary to process the case or cover so that the gap between the case and the cover is minimized.

The above description merely shows a specific preferred embodiment for the purpose of explanation and illustration of the present invention. For example, the shape and circuit of each component are not limited to those illustrated. In this embodiment, the key case 50a is fitted and fixed to the edge portion 56b of the key cover 56a, but may be fixed with screws. In that case, there is no need for a watertight structure as in the prior art, so assembly is facilitated.
Therefore, the present invention is not limited to the above-described embodiments, and includes many changes and modifications without departing from the essence thereof.

It is a perspective view which shows one Example of the key top of the push switch of this invention. It is a perspective view which shows an example of the key sheet | seat used by this invention. It is sectional drawing which shows an example of the key top of the conventional push switch. It is sectional drawing which shows the other example of the key top of the conventional push switch. It is a perspective view which shows the other example of the key top of the conventional push switch.

Explanation of symbols

50a Key case 50b Wiring extraction hole 52a Key sheet 52b Flexible wiring 54a Key top 55a Projection 56a Key cover 56b Edge 57a Hole 60 Insulation sheet 61 Switch (metal dome)
62 Insulation film

Claims (3)

An insulating sheet on which at least two wiring patterns to be connected are formed, a switch that is formed on the insulating sheet and connects the wiring patterns by pressing, and an insulating sheet including the switch is sandwiched between the insulating sheet and the insulating sheet. On the key top of the push switch
A key top of a push switch, wherein at least one surface of an insulating sheet including the switch is water-tightly covered with an insulating film.   2. The key top of a push switch according to claim 1, wherein an adhesive is used when water-tightly covering at least one surface of the insulating sheet including the switch with an insulating film. 2. The key top of a push switch according to claim 1, wherein the insulating sheet is disposed between the key case and the key top, and the key case and the key cover are fitted and fixed.

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