JPS6311727B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for forming a keytop composite, and more specifically, a method for forming a keytop composite in which a plurality of keytops (key buttons) are integrally formed on a single flexible insulating film. Regarding the formation method, the object is to provide a metallic key top composite body suitable for use in a thin film keyboard switch, which has good operability, is easy to assemble and manufacture, and has a metallic, high-class feel that does not erase display symbols. do.

As shown in Fig. 1, a keyboard switch used in a desktop computer etc. is made by separately forming a key top 2 made of a molded product with a symbol engraved on it, and enclosing it in the hole 1a of the cover 1, so that each key A structure in which the upper electrode 5 is brought into contact with and separated from the lower electrode 4 provided on the insulating base 3 by pressing the electrode 2 with a finger is known. However, the configuration shown in FIG. 1 has the disadvantage that each key top 2 must be individually sealed into the hole 1a of the cover 1 during assembly, making the assembly process complicated.

Further, as shown in FIG. 2, a thin keyboard switch is also known in which electrodes 9 and 9' are formed on the opposing surfaces of insulating sheets 6 and 6' that are placed vertically opposite each other with an insulating spacer 8 in between. In the figure, 10 is a base. In the configuration shown in FIG. 2, the upper insulating sheet 6 is formed of a flexible synthetic resin film such as a polyester film, and a symbol is displayed on the upper surface by printing or the like, and this is used as a pressing part. In this case, since the pressing part is flat with the other surfaces, it gives the user a feeling of anxiety as he cannot tell where he is pressing with his fingers, and also has the disadvantage that it does not give a luxurious feel. In addition, when pressed with a fingertip, a pressing force is applied to the entire pressing part, making it difficult to apply a concentrated load to the center of the pressing part, and as a result, contact reliability sometimes deteriorates.

The present invention has been made in view of the above points, and is a thin-film type keyboard switch with a key top (push button) that takes full advantage of the advantages of a thin-film type keyboard switch, namely, ease of assembly and good space factor. A method of forming a keytop composite for a keyboard switch is provided.

Hereinafter, the details of the present invention will be explained with reference to one embodiment of the present invention shown in FIGS. 3 to 5.

In FIG. 3, 11 is an insulating film made of synthetic resin that has both translucency and flexibility, for example,
Polyester, cellulose acetate materials, etc. are used. 12 is a contact pattern formed as an upper electrode on the lower surface side of the insulating film 11, and a conductive paste such as silver paste or carbon paste is applied by appropriate means such as printing or vapor deposition. In some cases, the contact pattern 12 may be a transparent electrode made of indium oxide, tin oxide, or the like.

13... is a first layer made of a known photoresist deposited on the upper surface of the insulating film 11 at a position corresponding to the contact pattern 12..., and 14... is a first layer of the first layer. 13...A second layer consisting of a thin metal film deposited on top of stainless steel,
An etched sheet metal material such as aluminum is selected.

Both layers 13 and 14 constitute a key top 15, and the second layer 14 is formed to have a larger area than the first layer 13, and a predetermined symbol 16 (fourth (see figure) is formed by etching.

Reference numeral 17 denotes a synthetic resin substrate, which is a hard insulating substrate made of a glass substrate or the like, and on its surface, contact patterns 18 on the lower side corresponding to the contact patterns 12 on the upper side are formed with conductive paste. It is formed as follows. Reference numeral 19 denotes a spacer made of a single insulating resin substrate, and holes 20 are formed at positions where the upper and lower contact patterns 12 and 18 face each other.

In order to form the key top 15 on the insulating film 11, first the insulating film 11 shown in FIG.
A first layer 13 made of photoresist on the entire surface
is applied to a uniform thickness, and then a second layer 14 of sheet metal is applied (FIG. 5b). Depending on the material and thickness, photoresist has a temperature of 5.
The second layer 14 is heated and hardened for about 20 minutes, and thus the second layer 14 is temporarily fixed on the first layer 13. In the state shown in FIG. Only the portion of layer 13 constituting keytop 15 is selectively hardened. This first
By curing the layer 13, the first layer 13 is completely adhered to the insulating film 11 and the second layer 14.

Next, as shown in FIG. 5C, a second layer 14 is formed.
A resin film 21 called a plating resist is formed on top by screen printing, and is heated and cured at around 80° C. for about 15 minutes. This resin film 21 is selected from one that can be removed with a solution that does not remove the cured photoresist and is acid-resistant. Metsuki resist M-18 is used. The resin film 21 is deposited only on the second layer 14 constituting the key top 15, and although not shown, in order to form a predetermined symbol 16 on the surface of the key top 15, the resin film 21 is applied to the area corresponding to the symbol. The film 21 is not applied.

In this state, when the second layer 14 made of a thin metal plate is etched in an acid solution, the uncured photoresist (first layer 13) is also removed at the same time, resulting in the state shown in FIG. 5d. leading to. In the state shown in FIG. 5d, it goes without saying that the symbol 16 is also formed by etching on the second layer 14, which is the surface of the key top 15. After that, the resin film 12 deposited on the second layer 14 is removed using trichloride (FIG. 5e), and finally, the contact pattern 12 is formed on the back surface of the insulating film 11. A keytop complex is formed.

In addition, in the above process, the contact pattern 12
is formed last, but with the contact pattern 12 as a transparent electrode and in the state shown in FIG. 5a, the insulating film 1 is
1. If formed in advance on the back side, the above-mentioned FIGS.
The steps can be performed similarly.

As described above in detail, the method for forming a keytop composite according to the present invention allows a plurality of keytops to be integrally formed at the same time.
and a second layer 1 on the side to be pressed with fingers.
4 is larger than the area of the first layer 13 therebelow, the pressing force is concentrated on the center, and therefore the upper electrode is loaded intensively, increasing contact reliability. can. In addition, since the second layer 14 is made of a thin metal film, it has the advantage of giving a metallic, luxurious feel, and since the symbol is formed by etching, there is no risk of the symbol disappearing due to wear. Overall, it is possible to provide a product with a key top that is easy to manufacture and has good operability as a thin film keyboard switch, and its practical value is remarkable.

[Brief explanation of the drawing]

1 and 2 are sectional views of essential parts showing different conventional examples, FIGS. 3 to 5 relate to an embodiment of the present invention, FIG. 3 is a sectional view of essential parts, and FIG. 4 is a sectional view of essential parts. The partial plan view and FIGS. 5a to 5f are explanatory diagrams showing the manufacturing process of the keytop composite. 11... Insulating film, 12... Contact pattern, 1
3... First layer (photoresist), 14... Second layer (metal thin plate), 15... Key top, 16... Symbol.

Claims (1)

[Claims] 1 A first layer made of photoresist is deposited on a single insulating film having translucency and flexibility, and a second layer made of a metal thin film is deposited on the first layer. Then, the first layer is exposed to light through a mask from the back side of the insulating film and cured into a desired pattern, and then a resin film made of a plating resist is printed in a desired pattern on the second layer. In this state, the second layer made of metal film is removed.
In addition to etching the layer in a desired pattern,
In this etching process, the first layer of partially cured photoresist is also removed in a desired pattern, and then the resin film deposited on the second layer is melted and removed, and the second layer is placed on the insulating film. A plurality of key tops each consisting of a first layer and a second laminated layer are formed at predetermined intervals, and the area of the first layer in each of the key tops is smaller than the area of the second layer. How to form a keytop complex.