JPH04308622A - Keytop for push button switch and manufacture of same - Google Patents

Abstract

PURPOSE:To disconnect penetration of moisture or water content to a contact part penetrating from the external, reduce the number of parts, and make a thin and compact device by holding and fixing a resin film with a film pressing part and a film fixing part. CONSTITUTION:A keytop 12 has a film pressing part 12c integrally formed of resin and a film pressing part 12c integrally provided with an outer circumference of the part 12b, and a resin film 10 is disposed covering the upper surface of the part 12b. The film 10 is held and fixed by the part 12c and a film fixing part 12d integrally provided at an upper part of the part 12c. A number, mark or symbol is printed at a part of the film 10 where the part 12b is positioned. The number of parts can be reduced, the keytop can be applied for a thin and compact device, a keytop having a display can be provided, and penetration of moisture or water content from the external to a contact part can be disconnected securely. In addition, the keytop 12 can be manufactured very speedily and easily.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a key top for a push button switch, which has a small number of parts and is suitable for thinning and miniaturization.
Furthermore, the present invention relates to a key top that can be used as a key top with a display and is suitable for a push button switch having a so-called drip-proof structure that prevents moisture and moisture from entering the contact portion from the outside.

0002

2. Description of the Related Art In recent years, with the miniaturization of electronic devices, there has been a demand for push button switches used in the operating sections of such devices to be smaller and thinner. Since some of these electronic devices are used in various environments, a variety of performances are required. As one of these, there is a demand for a push button switch having a so-called drip-proof structure, which blocks moisture and moisture from entering the contact portion from the outside.

[0003] In order to meet these demands, FIG.
There was a structure shown in . In FIG. 11, 61,6
2 is a sheet on which a contact pattern is formed, and the sheets 61 and 62 are arranged one above the other with a spacer 63 interposed therebetween.
By pressing the hinge-shaped key top 64 that is integrally formed with the panel 65 placed on the top of the seat 61,
A push-button switch is constructed by bringing a contact pattern (movable contact) formed on the sheet 61 into contact with a contact pattern (fixed contact) formed on the sheet 62 via a click spring 68.

[0004] In the push button switch having the above structure, the external
A drip-proof sheet 6 is provided between the sheet 61 and the key top 64 to prevent moisture and moisture from entering the cabinet 65 mainly from the key top side from penetrating into the switch contacts.
6, the drip-proof sheet 66 and the cabinet 65
A rubber packing 67 is interposed between them to provide a drip-proof structure. FIG. 11 is a plan view showing the shapes of the rubber packing 67 and the drip-proof sheet 66.

[0005]

[Problems to be Solved by the Invention] The push button switch with the above structure has a so-called drip-proof structure that prevents moisture and moisture from entering the contact portion from the outside, but it has a large number of parts and is difficult to operate according to the specified key top. It is not suitable for miniaturization because it requires a stroke, and the key top has a hinge mechanism with a predetermined length, and it is not suitable for miniaturization. It was also not perfect in terms of its so-called drip-proof property, which prevents water from penetrating the inside of the body.

The present invention has been made in view of the above-mentioned points, and has an excellent structure in which the structure of the key top itself is made difficult for moisture and water to enter from the outside, and has a small number of parts and is suitable for thinning and downsizing. An object of the present invention is to provide a key top with a drip-proof structure and a method for manufacturing the same.

[0007]

[Means for Solving the Problems] In order to solve the above problems, the present invention provides a fixed contact, a movable contact, and a key top arranged on the movable contact to press the movable contact. A key top of a push button switch comprising:
The key top has a key top part integrally formed by resin molding and a film holding part integrally provided on the outer periphery of the key top part, and the resin film is disposed so as to cover the upper surface of the key top part. , the resin film is sandwiched and fixed between a film holding part and a film fixing part integrally provided above the film holding part through a hole provided in the resin film.

[0008] The present invention is characterized in that numbers, symbols, symbol marks, etc. are printed on the surface of the resin film located above the key top portion.

Further, an upper mold having a cavity gap having the same shape as the upper part of the key top part and the film fixing part, a lower mold having a cavity having the same shape as the lower part of the key top part and the film holding part, and a resin film. By sandwiching the resin film between an upper mold and a lower mold, and injecting molten resin from a pin gate provided in either the upper mold or the lower mold, the lower part of the key top and the film are bonded. The resin film is deformed by the molten resin into a cavity having the same shape as the holding part, and is brought into close contact with the inner wall surface of the upper mold, and then flows into the cavity having the same shape as the film fixing part of the upper mold through a hole provided in the film. The method is characterized in that each cavity is filled with molten resin, and after the molten resin is solidified, the upper mold and the lower mold are removed.

0010

[Function] As described above, the upper surface of the key top part is covered with a resin film and the film is clamped and fixed by the film fixing part provided integrally with the cover film holding part, so the key top part Since the resin film is held between the film holding part and the film holding part, moisture and moisture from the outside can penetrate between the film holding part and the resin film, and further between the film holding part and the resin film, and penetrate into the contact part. Therefore, it is possible to reliably block moisture and moisture from penetrating into the contact portion from the contact portion.

Furthermore, since the key top is formed by resin molding on the resin film, the number of parts is reduced, resulting in a key top structure suitable for thinning and downsizing. Furthermore, since numbers, symbols, symbols, etc. are printed on the film surface located at the upper part of the key top part, the display becomes clear as a key top with a display.

[0012] Furthermore, as described above, by sandwiching a resin film between the upper mold and the lower mold, and injecting the molten resin through a pin gate provided in either the upper mold or the lower mold. As described above, a key top having an excellent structure can be manufactured extremely quickly and easily.

[0013]

Embodiments Hereinafter, embodiments of the present invention will be explained based on the drawings. FIG. 1 is a diagram showing the structure of a key top of a push button switch according to a first embodiment of the present invention, and FIG. 1(a) is a plan view;
FIG. 1(b) is a cross-sectional view (A-A cross-section), and FIG. 1(c) is a bottom view.

The key top 12 has a key top portion 12b integrally formed of a resin material, and a film holding portion 12c integrally provided around the outer periphery of the key top portion 12b. A resin film 10 is disposed on the upper surface of the key top part 12b so as to cover it, and the resin film 10 is held by a film holding part 12c and a film fixing part 12d integrally provided on the upper part of the film holding part 12c. It is clamped and fixed. As the resin material for the key tops 12, for example, thermoplastic polycarbonate resin or acrylic resin is used.

A pressing protrusion 12a that presses the movable contact of the key top 12 is integrally provided at the lower part of the film holding portion 12c, which is remote from the center of the bottom surface of the key top 12. Pressing protrusion 12 that presses the movable contact in this way
By providing a at a position away from the center of the bottom surface of the key top section 12, there is no need to arrange a contact section below the center of the bottom surface of the key top section 12. Therefore, by using a resin material that allows light to pass through the resin film and key tops,
By disposing a light emitting element in this portion, the key top surface can be made to stand out with the light from the light emitting element. In particular, by printing numbers, symbols, various symbols, etc. on the portion of the resin film 10 where the key top portion 12b is located, the number, symbol, or various symbols, etc. can be clearly seen from the key top portion 12b, improving the aesthetic appearance. becomes excellent.

FIG. 2 is a diagram showing an example of the structure of a push button switch using the key top 12 having the above structure. In the same figure,
A known membrane switch is formed. 16 and 17 are a movable contact pattern 16a and a fixed contact pattern 17, respectively.
The sheets 16 and 17 are fixed to the lower part of the stacked drip-proof frame 11 with their contact patterns 16a and 17a facing each other and a spacer 18 interposed therebetween. In addition, the contact pattern 16 of the sheet 16
A click spring 19 is disposed on the upper surface where a is located, and the pressing protrusion 12a of the key top 12 is located above the click spring 19. A light emitting element 23 such as a light emitting diode is arranged at the lower center of the key top portion 12b.

Numeral 11 is a drip-proof frame provided in a watertight manner surrounding the plurality of key tops 12 on the resin film 10, as will be described in detail later. The key top 12, drip-proof frame 11, sheets 16, 17, and other assemblies are housed in a housing 15. A panel 14 is disposed on the top of the housing 15. The panel 14 is provided with a long projection 14a, which is fitted into the long groove 11a of the drip-proof frame 11 in a watertight manner. The material of the drip-proof frame 11 may be either thermoplastic or thermosetting synthetic resin. In order to further improve the watertight fit, the drip-proof frame may be made of an elastic styrene elastomer or polyester elastomer.

[0018] By making the push button switch have the above-described structure, moisture and moisture that permeate through the gap between the key top 12 and the panel 14 can be prevented because the key top 12 and the drip-proof frame 11 are fixed to the resin film 10 in a watertight state. , it will not penetrate any further. In addition, the drip-proof frame 11 and the panel 14 are
As described above, since the long groove 11a and the long protrusion 14a are fitted in a watertight manner, moisture does not penetrate between the drip-proof frame 11 and the panel 14. Therefore, this push button switch has an excellent drip-proof structure.

3 to 5 are diagrams showing the structure of the operating section 1 of a push button switch in which the drip-proof frame 11 and the key top 12 are resin-molded in a resin film, and FIG. 3 is a plan view, and FIG.
is a sectional view taken along line AA in FIG. 3, and FIG. 5 is a sectional view taken along line BB in FIG. The drip-proof frame 11 has a plurality of key tops 1 as shown in the figure.
2 (six in the figure), and is provided on the resin film 10 in a watertight manner. To be more specific, as shown in FIG.
A long groove 11a having a rectangular cross section is formed on the upper surface of the upper portion 11b, and a fixing member 13 for fixing to a substrate or the like is integrally formed on the lower surface of the drip-proof frame 11. Here, the drip-proof frame 11 has a loop-shaped upper part 11b and a loop-shaped lower part 11c sandwiching the resin film 10, and the upper part 1
1b and the lower part 11c are only connected through the hole 20 shown in FIG. 6, moisture and moisture will not penetrate between the drip-proof frame 11 and the resin film 10 and further through the connection part. . That is, the resin film 10 and the drip-proof frame 11
The space between them has a watertight structure that prevents moisture and moisture from penetrating.

Next, a method of manufacturing the switch operating body 1 in which the drip-proof frame 11 and key tops are integrally formed on the resin film 10 by resin molding will be described. FIG. 6 is a plan view showing the outer shape of the resin film 10. As shown in the figure, the resin film 10 has a rectangular shape, and a plurality of holes 20 through which the molten resin passes during molding are provided at predetermined intervals in the portion forming the drip-proof frame 11. Furthermore, the portion forming the key top 12 is provided with small holes 21a (three holes in the figure) and large holes 21b through which the molten resin passes. Further, numbers, symbols, various symbols, etc. 24 are printed on the portion of the resin film 10 where the key top portion 12b is located. The printed surface may be either the top surface or the back surface of the resin film 10.

FIG. 8 is a diagram showing a structure in which a resin film is sandwiched between an upper mold and a lower mold to explain the key top manufacturing method, and FIG. 8 (a) corresponds to the B-B cross section in FIG. 1. The figure shown in FIG. 1B is a view corresponding to the AA cross section in FIG. As illustrated, a resin film is sandwiched between an upper mold 105 and a lower mold 106. The upper mold 105 has a cavity 110 having the same shape as the upper part of the key top part 12b (see FIG. 1) and a cavity 112 having the same shape as the film fixing part 12d, and the lower mold 106 has the same shape as the lower part of the key top part 12b. It has a cavity 111 having the same shape, a cavity 113 having the same shape as the film holding part, and a cavity 114 having the same shape as the pressing protrusion 12a.

As mentioned above, the lower mold 105 and the lower mold 10
The holes 21 are formed in the resin film 10 by sandwiching the resin film 10 between the holes 21 and 6 and injecting molten resin through the pin gate 107 located above the large hole 21b.
cavities 114, 111, of the lower mold 106 through b.
113 respectively.

At this time, as shown in FIG. 8(b), the cavities 111, 11 formed in the lower mold 106
Since the parts other than 3 and 114 are strongly sandwiched between the upper and lower molds, the inflowing molten resin flows into the cavity 110 of the upper mold 105 while deforming the film 10, and further flows into the holes formed in the resin film 10. It flows into the cavity 112 of the upper mold 105 through 21a. As a result, the resin film 10 is deformed and the cavity 11 of the upper mold 105 is
Closely adheres to the inner wall surface of 0. When the upper mold 105 and the lower mold 106 are removed with the molten resin solidified, the key top 1 with the surface of the key top part 12b covered with a resin film as shown in FIG. 1 is obtained.
2 is made.

In the above embodiment, the pin gate 107 is provided in the upper mold 105, and the cavities 111, 1 of the lower mold 106 are passed through the large hole 21b formed in the resin film 10.
Although the molten resin was injected into 13 and 114, it directly fell into the lower mold 10.
A pin gate may be provided in the cavity 114 of No. 6 to inject the molten resin.

The gist of the manufacturing method of the present invention is that the resin film 1
0 into the shape of the cavity 110 of the upper mold, and the key top 12 is resin-molded into a resin film, and therefore it is also influenced by the shape of the key top 12 and the injection conditions of the molten resin. In this example, the thickness of the resin film is 0.2 mm, and the height of the key top 12 is 1/2 of the outer diameter.
When manufactured as follows, the resin film 10 deformed and adhered to the inner wall surface of the cavity 100 of the upper mold 105.

When injecting the molten resin, it is necessary to appropriately set the molten resin temperature, injection (injection) pressure, injection speed, injection time, and mold temperature. In this example, the molten resin temperature was 240°C, the mold temperature was around 80°C, and the injection time was 3.
Molding with a good yield was achieved when the injection pressure of the injection molding machine was set at 1400 kg and the injection speed was set at 15 mm/sec.

The drip-proof frame 11 is formed, as shown in FIG. 9, by using an upper mold 101 having a cavity 112 having the same shape as the frame upper part 11b (see FIG. 5) and a mold having the same shape as the frame lower part 11c (see FIG. 5). By sandwiching the resin film 10 between a lower mold 102 having a cavity 113 and injecting molten resin from the pin gate 103, the molten resin flows into the cavity 112 of the upper mold 101 through the resin reservoir 22, and the resin is further poured into the cavity 112 of the upper mold 101. The cavity 11 of the lower mold 102 passes through the hole 20 of the film 10
3. By removing the upper mold 111 and the lower mold 102 with the resin solidified, a drip-proof frame 11 that surrounds a predetermined area of the resin film is formed.

FIG. 10 is a diagram showing another structure of the key top of the push button switch according to the second embodiment of the present invention.
a) is a plan view, FIG. 10(b) is a cross-sectional view (A-A cross section),
FIG. 10(c) is a bottom view.

The key top 12 has a key top portion 12b integrally formed of a resin material, and a film holding portion 12c integrally provided around the outer periphery of the key top portion 12b. A resin film 10 is disposed on the upper surface of the key top part 12b so as to cover it, and the resin film 10 is held by a film holding part 12c and a film fixing part 12d integrally provided on the upper part of the film holding part 12c. The key top is clamped and fixed in the same way as the key top shown in FIG. This key top 12 is different from the key top shown in FIG.
It is provided in the lower central part of the film holding part 12c so as to protrude from the lower surface of the film holding part 12c.

The key top 12 is also made of thermoplastic polycarbonate resin or acrylic resin, which is the same as the key top shown in FIG. Furthermore, the manufacturing method is the same as the method for manufacturing the key top shown in FIG. 1, except that the shape of the cavity of the lower mold changes depending on the shape of the key top 12, and therefore the explanation thereof will be omitted.

In this embodiment, a resin material that transmits light is used for the resin film 10 and the key top 12, and
By printing numbers, symbols, various symbols, etc. on the part of the resin film 10 where the key top portion 12b is located, the numbers, symbols, various symbols, etc. can be clearly seen from the key top portion 12b, and the appearance is improved. It will be excellent.

Note that the key top portion 12 of the key top 12
The shape of b is not limited to the above example; for example, the plane need not be circular, and may of course be rectangular or polygonal, for example. Further, in the above embodiment, four film holding parts 12c are integrally provided in a radial manner on the bottom outer periphery of the key top part 12b, but the film holding parts 12c are not limited to this, and are formed by connecting the key top 12 and the resin film. In order to increase the adhesion strength with 10, the number of radial film holding parts 12c may be further increased, or the number of film fixing parts 12d may be increased.
You can also connect them in a ring. Key top 12
The upper and lower molds 105 and 106 are used to apply the resin film 1 to the corresponding location.
The number and shape of the film holding part 12c and the film fixing part 12d are not limited as long as they can strongly hold the film.

[0033]

[Effects of the Invention] As explained above, according to the present invention, the upper surface of the key top portion is covered with a resin film, and the film is held and fixed in a watertight state by the film fixing portion provided integrally with the film holding portion. Therefore, the following excellent effects can be obtained.

(1) The number of parts is small, and the key top is suitable for thinning and miniaturization, and also has a display. (2) Moisture and moisture from the outside will not penetrate into the contact area between the film fixing part and the resin film, or between the film holding part and the resin film, and moisture and moisture from the outside will not penetrate into the contact area. This key top is suitable for drip-proof push button switches. (3) Furthermore, according to the manufacturing method of the present invention, the key top can be manufactured extremely quickly and easily.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the structure of a key top of a push-button switch according to the present invention; FIG. 1(a) is a plan view, and FIG.
-A sectional view, and FIG. 1(c) is a bottom view.

FIG. 2 is a partial cross-sectional view showing the structure of a push button switch using the key top of the present invention.

FIG. 3 is a plan view of the operating section of the push-button switch, which is composed of a resin film, a key top, and a drip-proof frame.

FIG. 4 is a sectional view taken along line AA in FIG. 3;

FIG. 5 is a sectional view taken along line BB in FIG. 3;

FIG. 6 is a plan view of a drip-proof resin film.

FIG. 7 is a diagram showing the shape of holes in the resin film of the key top forming portion.

FIGS. 8(a) and 8(b) are diagrams for explaining the resin mold of the key top.

FIG. 9 is a diagram for explaining a resin mold of the drip-proof frame.

FIG. 10 is a diagram showing the structure of another key top of the push button switch of the present invention, in which FIG. 10(a) is a plan view, FIG. 10(b) is a sectional view taken along line A-A in FIG. ) is a bottom view.

FIG. 11 is a cross-sectional view showing a structural example of a conventional push button switch having a drip-proof structure.

FIG. 12 is a plan view showing the shapes of a conventional rubber packing and a drip-proof sheet.

[Explanation of symbols]

1 Switch operating body 10
Resin film 11 Drip-proof frame 12 Key top 13 Fixing member 14 Panel 15 Housing 16 Sheet 17 Sheet 18 Spacer 19 Click spring

Claims (3)

[Claims] 1. A key top for a push button switch, comprising a fixed contact, a movable contact, and a key top disposed above the movable contact and pressing the movable contact, the key top being arranged opposite to each other. It has a key top portion integrally formed by resin molding and a film holding portion integrally provided on the outer periphery of the key top portion, and a resin film is disposed so as to cover the upper surface of the key top portion, and the A key top for a push button switch, characterized in that the resin film is clamped and fixed between a film holding part and a film fixing part integrally provided above the film holding part through a hole provided in the resin film. 2. The key top of the push button switch according to claim 1, wherein a number, symbol, symbol mark, etc. is printed on the surface of the resin film located above the key top portion. switch key top. 3. An upper mold having a cavity having the same shape as the upper part of the key top part and the film fixing part, a lower mold having a cavity having the same shape as the lower part of the key top part and the film holding part, and a resin film. The resin film is sandwiched between the upper mold and the lower mold, and a pin gate provided in either the upper mold or the lower mold is connected to the lower part of the key top and the same shape as the film holding part. By injecting the molten resin into the cavity gap of the molten resin, the resin film is deformed by the pressure and heat of the molten resin and brought into close contact with the inner surface of the cavity of the upper mold. 2. The upper mold and the lower mold are removed after the molten resin flows into cavities having the same shape as the film fixing part of the mold and fills each cavity with the molten resin, and the molten resin is solidified. A method of manufacturing key tops for push button switches.