JPH08227629A - Manufacture of key board - Google Patents

Abstract

PURPOSE: To manufacture a die of a diversified key board, in which mixing of color phase of push buttons arranged adjacent to each other in the boundary thereof is prevented, at a reduced manufacturing cost in a short time. CONSTITUTION: Multiple single-shape dome-like rubber push buttons 1 having a preset sliding part (a) are prepared. Multiple printed boards, which are respectively provided with a fixed contact of different arrangement patterns on a flexible thin polyester film base material 10, are prepared. The push buttons 1 are fixed onto the printed board 10 through the pressure sensitive adhesive or the adhesive 5 in the condition that they are separated from each other so as to surround the fixed contact.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is useful for a method of manufacturing a keyboard, and particularly for a key input in which a single-shaped push button having one sliding portion is separately arranged and attached to one board. The present invention relates to a method of manufacturing a keyboard.

[0002]

2. Description of the Related Art Conventionally, various methods have been used for manufacturing a rubber cover member (hereinafter referred to as a cover member) for a keyboard used for key input or the like. For example, as shown in FIG. 5, a cover member carrying a movable contact is prepared in which a large number of push button portions 7 and a base portion 8 are connected and integrated, and this has a fixed contact arranged in a predetermined pattern. A method of manufacturing a keyboard, which is arranged to face a printed circuit board, is used. For the cover member 9 used at this time, a mold having a cavity matching the shape of the cover member is manufactured in advance, and a movable contact made of vulcanized conductive rubber is used as a fixed contact (not shown). ) After being embedded in the cavities corresponding to the arrangement pattern, an unvulcanized insulating rubber is placed thereon, and heated and pressed to connect and integrate a large number of push button portions 7 and base portions 8. can get. (This is called conventional method A.)

Further, in the cover member obtained by integrally molding in the same manner as in the conventional method A, perforations are provided in advance in the base portion for each push button arrangement so that the number of push button arrangements can be increased or decreased. There is also a manufacturing method in which, when the unit body of the cover member is incorporated into the device, only the unnecessary push button portion is cut off and incorporated into the case of the keyboard. (This is referred to as a conventional method B.) Further, a unit body of a cover member having a plurality of push button portions on an L-shaped base portion and a square-shaped base portion obtained by integrally molding in the same manner as in the conventional method A. In addition to preparing a unit body of a cover member having a plurality of push button parts, both unit bodies can be placed, and an insulating plastic sheet having openings in the arrangement pattern of fixed contacts is prepared. After arranging adhesives or adhesives at intervals around the opening edge of, the members formed by covering and fixing the entire surface of the insulating plastic sheet in each unit body are aligned with the printed circuit board having fixed contacts. There is also a method of manufacturing a keyboard that is incorporated into a keyboard case. (This is called the conventional method C.)

[0004]

However, in the conventional method A, if the fixed contact array pattern is different even at one place, the cover member 9 as shown in FIG. In order to obtain this, it is necessary to prepare a new mold. Moreover, one part of the arrangement of the push button part that was changed when manufacturing this new mold affects the expansion and contraction of the entire cover member after molding and the expansion and contraction during use, so repeat trial and error again. While designing, manufacturing and inspecting the mold is required. In addition, the mold of the cover member for the keyboard requires a large size of about 50 cm × 50 cm, so the material cost itself is high, and since the processing time is long, the mold cost is also high. In the case of molding by using, there is a disadvantage that a large press machine itself must be prepared.

In order to manufacture a keyboard cover member having a plurality of push button portions having different hues, which has recently been demanded, an unvulcanized portion of a different hue is formed in each of the engraved portions for forming the push button portion of the mold cavity. After placing the insulating rubber raw material at the same time, since pressure heating is performed, the hues are easily mixed at the boundary between the push button portions of the obtained cover member, and therefore the product does not have the intended hue boundary. The yield is extremely poor and it is not suitable for high-mix low-volume production.
As a result, there is a drawback that the cost becomes high.

Also in the case of the conventional method B, since the unnecessary push button portions are removed only for each row, the external dimensions of the keyboard are limited to the external dimensions of the cover member obtained by integrally molding in advance. There are disadvantages that are limited. Therefore, when it is desired to obtain a keyboard whose outer dimensions exceed the outer dimensions of the cover member, or when it is desired to obtain a keyboard having push button portions arranged in a zigzag pattern such that the push button portions are not necessarily arranged in a row. Another mold has to be manufactured, which increases the cost. It should be noted that although there are restrictions such as the combination of a unit body cut off from the perforations of the cover member and one that is not cut, it is possible to manufacture a keyboard with a larger external dimension than the original cover member. However, since there is no base body that supports each unit body in common, there is also a disadvantage that alignment is difficult when incorporating the unit body. In addition, since the base part around the push button part includes a part with perforations and a part without perforations, the holding itself of the push button part is uneven. Since it bends flexibly, it has the drawback of poor operability.

Further, in the conventional method C, since the layout change of the push button portion is limited to within the range of the combination of the unit bodies, a new mold is still required to obtain the keyboard having the push button portion arranged outside these ranges. The cost will be high. Further, the unit body of the cover member and the insulating plastic sheet are fixed with an adhesive or an adhesive at a distance, but since the range to be fixed with the adhesive or the adhesive is wide, the unit or the It is difficult to fix both of the insulating plastic sheets without causing deformation. Further, for example, even if the unit body and the insulating plastic sheet can be adhered to each other without deformation, there is a disadvantage in that the unit body and the insulating plastic sheet may be deformed due to long-term use due to a difference in thermal contraction rate between them. Both the conventional method B and the conventional method C can be avoided as a method of preventing hue mixing at the boundary of the push button portion by changing the hue for each unit body, but the boundary between adjacent push buttons on the unit body can be avoided. There is also the disadvantage that mixing of hues in parts is unavoidable.

[0008]

SUMMARY OF THE INVENTION The present invention is directed to a method of manufacturing a keyboard which overcomes the disadvantages of these prior art methods, including: 1) a dome of a single shape having one predetermined sliding portion. Process for preparing a large number of rubber push buttons, 2) a process for preparing various types of printed circuit boards having fixed contacts with different arrangement patterns on a flexible thin polyester film substrate, and 3) The push buttons are spaced apart from each other so as to surround the printed circuit board,
The present invention provides a method of manufacturing a keyboard having a plurality of types of push button arrangement patterns using a push button having a single shape, which comprises a step of fixing with a pressure sensitive adhesive or an adhesive.

The present invention relates to a method of manufacturing the above-mentioned keyboard, which will be described in more detail below. As a result of various studies on the method of manufacturing an inexpensive keyboard, which can cope with small-lot production of a wide variety of products and the hues do not mix at the boundaries of the push button parts, the present inventors have used a mold of about 5 cm × 10 cm. , A large number of single-shaped dome-shaped rubber push-buttons with one sliding part, and various types of printed circuit boards with fixed contacts with different arrangement patterns on a flexible thin polyester film substrate The push button is separated from each other so as to enclose the fixed contacts on the printed circuit board, an adhesive or an adhesive is applied to the leg board side, and it is fixed to the board by curing. By doing so, it is not necessary to manufacture a mold for each contact layout pattern, and a keyboard having push buttons with various layout patterns can be easily obtained, which also saves costs. However, if this push button is fixed to the substrate with an insulating adhesive or adhesive, it can also be used as a resist layer for the conductive pattern, and this mounting cost can be reduced. The present invention has been completed by finding that it can be applied to various kinds of printed circuit boards made of a flexible thin polyester film having different arrangement patterns of contacts, and thus can be quickly applied to various kinds of small quantities.

Further, like an example of a conventional push button, a composite conductive sheet material prepared by coating a part or all of one surface of an insulating plastic film with a conductive thin layer material is prepared,
By heat molding this with a press machine etc., leaving the flat plate base on the same sheet material, and repeatedly sliding the push button that is convexly curved from the base to the insulating plastic film side, the insulating plastic film part Due to the difference in hardness, flexibility, and heat shrinkage from the conductive thin layer material, the conductive thin layer may be peeled off from the insulating plastic film after long-term use. Therefore, since the push button of the keyboard according to the present invention has the sliding portion, it is formed of only the rubber layer, and has a unique dome shape with excellent spring characteristics.
The feeling of operation is good, and the peeling of the conductive layer from the film due to repeated pressing operations does not occur, and the push buttons are supported by the base material made of a polyester film in a state where they are spaced apart from each other. Therefore, the variation of the pressing load and the collapse of the push button in an unintended direction occur due to the irregular elastic deformation of the base portion as seen in the keyboard member in which the conventional push button portion is connected to the rubber base portion. And has the advantage that the pressing force of all the arranged push buttons is uniform and constant,
It has been found that, even if a large number of push buttons having different hues are arranged, since the push buttons are arranged separately, the hue boundary is not unclear.

The polyester film used here is flexible but has a small stretchability, and is excellent in dimensional stability, electrical insulation, physical strength, chemical resistance, heat resistance and the like. Therefore, it is optimal as a keyboard member, and because it has excellent adhesion to ink,
It has strong adhesion to the conductive pattern that forms the fixed contact, and unless a conductive pattern is provided on the sliding part, there is no fear of peeling due to repeated pressing operations, and a long-life keyboard device can be obtained. There are also advantages. Further, since this polyester film has flexibility, it has an advantage that it can be easily incorporated into the case of the keyboard device.

The thickness of this polyester film is less than 150 μm in order to ensure flexibility, and 20 μm or more in order not to cause damage during handling. In order to obtain the most preferable performance, the thickness may be around 100 μm. If the polyester film that is the base material is installed in the keyboard device, it will be blocked by the case and will not come into contact with the eyes of the operator, so it is not necessary to color it in particular, but this is a thin polyester film of 20 to 150 μm. If the thickness is in this range, the polyester film itself is thin, and therefore it is generally transparent to show a transparent or cloudy appearance even if a coloring agent is contained. Since the polyester film itself is shielded by the keyboard case and does not come into contact with the eyes of the operator, it is not necessary to consider the addition of the coloring agent.

The keyboard obtained in the present invention is transparent to the substrate itself, and the single-shaped pushbuttons fixed by an adhesive or a pressure-sensitive adhesive are separately arranged, so that the entire substrate is Since the push button is not covered with the push button, the push button has an advantage that the positioning can be easily and accurately performed, and a keyboard having no dimensional deviation can be obtained. Further, since the substrate itself is transparent and the push buttons are arranged apart from each other, there is an advantage that foreign matter can easily be found in the apparatus. In the keyboard obtained by the manufacturing method of the present invention, as long as the push button has a single shape, its hardness and hue are arbitrary, and push buttons having different hardness and hue may be appropriately combined and used. The material of the push button is arbitrary as long as it can be fixed to the polyester film as long as it has rubber elasticity, and specifically, natural rubber, polybutadiene, polyisoprene, SBR,
Diene-based synthetic rubber such as neoprene, ethylene-propylene-based, urethane-based, polyester-based, silicone-based synthetic rubber or a combination thereof may be used, which are heat resistant, weather resistant, and electrically insulating. It is preferable to use a silicone rubber having excellent properties and precision moldability.

This single-shaped dome-shaped rubber push button is 5 cm
By using a mold of about 10 cm, multiple molding by known methods such as compression molding, injection molding, transfer molding, etc. After molding, a circular or quadrangular shape so that it becomes a single shape push button with one sliding part each It should be separated from. The adhesive used for fixing the dome-shaped rubber push button and the printed circuit board made of polyester film is mainly rubber-based such as natural rubber, SBR, recycled rubber, polyisobutylene, block rubber, etc. And a copolymer of acrylic acid, methacrylic acid, acrylamide, vinyl acetate, styrene and other monomers, and a silicone-based silicone resin obtained by the condensation reaction of silicone rubber and a hydrolyzate of organochlorosilane. Examples thereof include non-crosslinking type, thermosetting type, and room temperature curing type, and examples of the adhesive include thermosetting type urea resin, phenol resin, resorcinol-formaldehyde resin, epoxy resin, polyisocyanate, and silicone. Rubber is also a thermoplastic type of polyvinyl acetate. , Polyvinyl acetal, polyvinyl alcohol, various acrylic and methacrylic acid esters, cyanoacrylic acid esters, polyamides, polyesters, polyamide imides, polybenzimidazoles, polyimides, and further composite polymer type polyvinyl acetal / phenolic resins, rubber / phenolic resins Examples thereof include epoxy resins and nylon resins.

When fixed using this adhesive,
The push button is replaceable, and when it is bonded using an adhesive, the adhesive strength is greater than that of an adhesive, so there is no misalignment and it has excellent durability, there is no tack on the surface after curing, and no dust adheres. Although it has an advantage, it is preferable to use an insulating silicone rubber because it can also be used as a resist layer among these, and this is temporarily fixed by the adhesive force of the uncured silicone rubber itself,
Then, the uncured silicone rubber is vulcanized and cured by heating, heating, pressurizing, or humidifying to fix the silicone rubber.

The silicone rubber may be of a radical reaction type, an addition reaction type or a condensation reaction type, and a silane coupling agent or a titanate coupling agent is kneaded into them in order to enhance the adhesiveness. However, it can be vulcanized by heating for a short time, and has excellent initial tackiness. It is an addition reaction type that uses an organohydrogenpolysiloxane and a platinum-based catalyst. Preferably
According to this, it is possible to improve the positional accuracy of the temporary fixing of the push button to the substrate, and it is possible to provide the advantage that the tack property is eliminated even when the push button is pressed and lowered, and the transportability is improved.

Further, the cover member obtained according to the present invention does not fix the push button and the printed circuit board only by temporary fixing by means of adhesive force, but also by vulcanization and curing using uncured silicone rubber. If fixed, there is no displacement of the push button even if the push button is operated for a long period of time, and there is provided a cover member that is no different in function from the conventionally known jointly integrated cover member. The push button and the printed circuit board may be optionally treated with an appropriate primer such as a silane coupling agent or a titanate coupling agent in advance.

Regarding the application of uncured silicone rubber to the push button or the printed circuit board, masking is placed on the contact so that it is not applied to the fixed contact, or after the pattern plate which is not applied is manufactured. The casting method, topping method, printing method, transfer method or the like may be applied on the entire surface of the substrate or only on the fixed contact peripheral edge or on the chest substrate side of the push button member. The application of the uncured silicone rubber may be normally 0.005 to 2 mm, preferably 0.02 to 0.3 mm, which enables efficient adhesive fixing.

Next, the cover member of the keyboard obtained according to the present invention will be described with reference to the accompanying drawings. Figure 1,
FIG. 2 is a vertical cross-sectional view of the main part of the cover member of the keyboard obtained by the present invention, and FIG. 1 shows a dome-shaped rubber having one sliding part a having a slanted wall structure. A push button 1 having a leg portion 2 bonded and fixed with a silicone rubber layer 5 so as to surround a fixed contact 4 on a printed circuit board 3. In FIG. 2, a dome-shaped rubber push button 1 having one sliding portion a is formed. It is shown that the leg portion 2 having the mounting groove is fitted to the protrusion 6 provided in the vicinity of the fixed contact 4 of the printed circuit board 3 and is bonded and fixed with the silicone rubber layer 5 to surround it. The first one is advantageous in that the shape of the push button portion of the keyboard cover member of this type can be diverted completely. Further, FIG. 3 shows an embodiment showing a state in which a push button member is arranged and fixed on a flexible printed circuit board having a comb tooth electrode, a wiring pattern, and a lead electrode.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of the present invention will be described based on Examples.

[0021]

【Example】

(Manufacture of standard push button 1) Silicone rubber compound K
70 parts of E742U [trade name of Shin-Etsu Chemical Co., Ltd.], 30 parts of acetylene black powder and 0.5 parts of dicumyl peroxide
The conductive rubber with added parts is molded under the conditions of 50 kg / cm ² and 170 ° C to make a conductive contact with an outer diameter of 4.0 mm. Then, this is used for forming pushbuttons that were previously manufactured for other purposes. The mold is diverted and placed at a position corresponding to the predetermined movable contact of this mold, and then silicone rubber compound KE95 is applied to this mold.
1U [Product name of Shin-Etsu Chemical Co., Ltd.] 100 parts of dicumyl peroxide 1.5 parts and colorant (white) 0.5 parts was added to the insulating rubber compound, and 50 kg / cm ² , 170
24 pushbutton members with outer diameter of 9.5 mm, inner diameter of 5 mm, dome inner diameter of 8.7 mm, height of 3.3 mm, and thickness of 0.8 mm, formed by integrally molding conductive contacts and insulative rubber in a column of 13 mm , Row
We produced a large number of pushbutton member precursors surrounded by thin-walled wires for adjusting the expansion and contraction that were provided at a parallel interval of 15 mm. One of them was a rectangle with a length of 13 mm and a width of 15 mm. Split.

(Manufacture of standard push button 2) 100 parts of ethylene propylene rubber / EPDM501A [trade name of Sumitomo Chemical Co., Ltd.], 40 parts of calcium carbonate, 3 parts of dicumyl peroxide, 1 part of vulcanization aid, colorant (Red) 0.5 parts and 40 parts of paraffinic softener were added to the insulating rubber compound in the same mold used for the standard push button 1, and 50
Molded under the conditions of kg / cm ² and 170 ℃, produced a large number of standard pushbuttons 2 in the same manner as standard pushbuttons 1, printed conductive contacts with pad printing, and then produced one of them with a length of 13 mm, It was divided into rectangles with a width of 15 mm.

(Manufacture of Standard Push Button 3) The standard push button 1 uses the same raw material except that the colorant is black, and the same mold is used as the standard push button 1 manufactured under the same molding conditions. And produced a large number of standard pushbuttons 3, one of which was vertically
It was divided into a rectangle of 13mm and 15mm in width.

Example 1 (Preparation of Printed Circuit Board A) Width 10 cm, Length 15 cm, Thickness 100
The diameter shown in Fig. 3 (b) on the polyester film 10 of μ
Conductive carbon layer 4.0 mm in diameter on 3.5 mm silver paste 11
Comb-shaped electrodes (fixed contacts) 13 on which 12 are formed are arranged in a regular lattice pattern of 8 rows and 4 columns at a pitch of 17 mm in length and width, and a total of 32 pieces are arranged, and the comb-shaped electrodes are not coated on the substrate 14 having respective extraction electrodes. Patterned plate and addition reaction type self-adhesive silicone rubber KE1800RTVABC [Shin-Etsu Chemical Co., Ltd.] with platinum catalyst added as a resist layer and adhesive
[Product name] was printed by screen printing with a thickness of 0.03 mm excluding the comb-teeth electrode portion, and a flexible printed circuit board A1 provided with a silicone rubber layer was purchased. Next, the flexible printed circuit board A1 is the same as the member, but the flexible printed circuit board shown in Table 1 below is provided except for the position of the comb-teeth electrode 13 (the comb-teeth electrode portion is not covered with the resist layer). It was

[0025]

[Table 1]

(Fixing of Standard Push Buttons to Printed Circuit Board) Next, the standard push button 1 and the standard push button 3 are arranged in the first and second stages so as to surround the comb electrodes on the printed circuit boards A1 to A5. Separate them on the 4th row and set them at 150
When the silicone rubber was cured by heating it in an oven at ℃ for 30 minutes, two types of standard pushbuttons with a single shape but different coloring were firmly bonded so as to enclose the fixed contacts on the printed circuit board. The obtained cover member was obtained. It was then incorporated into the keyboard, which was easily and accurately positionable due to the transparent nature of the printed circuit board. The keyboard thus obtained passed the repeated keystroke test 10 million times, and no peeling of the conductive pattern was observed.

Since the mold used to manufacture the standard push button of the first embodiment is small, the manufacturing cost is 50 cm × which is a combination of many conventional push button parts and push button base parts.
It is 1/5 of the manufacturing cost of a large-sized keyboard mold of 5 cm or the like, and it is not necessary to manufacture separate molds corresponding to the substrates A1 to A5. Furthermore, when the fixed contacts (of the comb-teeth electrodes) are arranged slightly differently as in the case of the substrates A1 to A5, one different point affects the entire keyboard cover member, and the expansion and contraction after molding, during use It is not necessary to newly design, manufacture, and inspect the mold by trial and error in anticipation of expansion and contraction, and neither keyboard has mixed hues at the boundary between adjacent pushbuttons.

Example 2 (Preparation of Printed Circuit Board B) Width 150 mm, Length 480 mm, Thickness
A polyester film of 50 μm and a polyester film having a wide area of 15 mm × 36 mm only in the lower right part of the polyester film are prepared, and a 4.0 mm diameter is applied to these polyester films on a silver paste having a diameter of 3.5 mm as shown in FIG. The comb-teeth electrodes (fixed contacts) formed by forming the conductive carbon layer are provided in the arrangement as shown in Table 2, and B1 to B
5 various printed circuit boards were obtained.

[0029]

[Table 2]

Then, for each of the substrates B1 to B5, a silane coupling agent layer was formed by screen printing so as to surround the comb electrodes, and then standard push buttons 1, standard push buttons 2, A commercially available epoxy resin / nylon-based adhesive was sequentially applied to each leg of the push button 3 so that the weight of the silane coupling agent layer provided earlier was applied and fixed. <The layout of the standard push buttons on the boards B1 to B5 is shown in FIG. 4 (a).
-See (e)> When these are left to stand for 2 hours at room temperature, three types of standard push buttons having a single shape but different in hue and / or hardness are adhesively fixed so as to surround the fixed contacts of the printed circuit board. A cover member was obtained.

Next, these cover members were assembled in the keyboard. The parts other than the push buttons spaced apart are transparent, and the inside of the keyboard case can be confirmed from above, so that the assembly is easy and the positioning is possible. Was also accurate. This keyboard passed the keystroke test of 10 million times and there was no peeling of the conductive pattern. Since the standard push buttons 1 to 3 commonly use the mold used in Example 1, the cost of the mold was low. In addition, trial-and-error die design, manufacturing, and inspection are not required, so many types of keyboards can be manufactured in a short period of time. There was nothing to do.

[0032]

Industrial Applicability The present invention relates to a method for manufacturing a keyboard. According to the method, a keyboard excellent in appearance without mixing of hues can be manufactured, and the keyboard has a size of 5 cm.
It is possible to manufacture a wide variety of printed circuit board keyboard members with different fixed contact arrangement patterns by simply making a small mold of about 10 cm. Therefore, there is no need to design, manufacture, or inspect a mold, so it is cheap to produce a wide variety of products in small quantities. Is possible with
Moreover, there are advantages that delivery time can be shortened and production efficiency can be improved. Since the push buttons are made of dome-shaped rubber, the push button operation is smooth, and since they are supported by the polyester film, there is an advantage that the pushing force of all the push buttons arranged is uniform and constant. further,
Since the board is flexible, it is easy to incorporate the keyboard member into the keyboard case. Moreover, in addition to the board itself of the keyboard member being transparent, the push buttons are arranged separately from each other, so that the keyboard case Since the inside can be confirmed, it has the advantage that it can be installed in the correct position.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a main part of a keyboard cover member obtained according to the present invention.

FIG. 2 is a longitudinal sectional view of an essential part of another keyboard cover member obtained according to the present invention.

FIG. 3A is a perspective view of a flexible printed circuit board used in Example 1 of the present invention, and FIG. 3B is a cross-sectional view of the comb electrode.

FIGS. 4A to 4E are plan views showing a multi-key cover member having push buttons having different arrangement patterns, which are obtained according to the present invention.

FIG. 5 is a perspective view of a conventionally known keyboard cover member.

FIG. 6 is a perspective view of another conventionally known keyboard cover member.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Push button a ... Sliding part 2 ... Leg part 3, 10 ... Polyester substrate 4 ... Fixed contact 5 ... Adhesive 6 ... Protrusion 7 ... Push button part 8 ... Base part 9 ... Keyboard cover member 11 ... Silver paste layer 12 ... Conductive carbon layer 13 ... Comb electrode 14 ... Extraction electrode

Claims (1)

[Claims] 1. A step of preparing a large number of single-shaped dome-shaped rubber push buttons having one predetermined sliding portion. 2) Different arrangement patterns on a flexible thin polyester film base material. Step of preparing various kinds of printed circuit boards provided with fixed contacts of 3) Fixing the push buttons on the printed circuit board with an adhesive or an adhesive so as to be spaced from each other so as to surround the fixed contacts. A method of manufacturing a keyboard having a plurality of types of push button arrangement patterns using a push button having a single shape, which comprises the steps of: