JPH11191332A - Sheet-like key top and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet-like key top capable of providing a display part with a high quality without enlargement and strain of letters and symbols printed on a synthetic resin film and to provide a method for manufacturing the sheet-like key top. SOLUTION: This sheet-like key top is produced by using a flexible synthetic resin film 2 having a through hole in the center and arranged above the contact film and integrally forming a key top 1 and a projected part 3 made of a light transmissive or non-transmissive thermoplastic resin while sandwiching the film 2 between the key top and the projected part 3 from up and down sides and keeping key top 1 and the projected part 3 continuous through the through hole of the film 2. After that, a display part 5 for letters and symbols is formed on the surface of the thermoplastic resin key top 1 produced by such a manner.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a push-button switch for use in an input section of a portable device / device control section, which is arranged above a switch contact and which presses the switch contact from above to turn it on / off. The present invention relates to a sheet-like key top and the like.

[0002]

2. Description of the Related Art Characters and symbols are printed on the upper or lower surface of a transparent or translucent synthetic resin film having flexibility and are curved upward, and at the same time, a thermoplastic resin body is directly fused into the curved portion. A structure of a push-button switch in which a key top is formed by bonding through a bonding agent or an adhesive layer is known as described in JP-A-7-326252.

[0003]

However, after printing characters and symbols on the synthetic resin film, the synthetic resin film is bent upward at high temperature and high pressure by thermoplastic resin molding. And distortion occur. In addition, the expansion of characters and symbols, and the provision of a film elongation prevention layer as a way to avoid distortion, is carried out, but the elongation rate of the film varies slightly depending on the resin temperature and injection pressure during molding of the thermoplastic resin. A phenomenon in which the enlargement ratio of the character is different occurs, and a sufficient effect is not always obtained.

[0004]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention uses a flexible synthetic resin film having a through hole in the center disposed on the upper portion of a contact film, and uses a light-transmitting synthetic resin film. The key top and the protruding portion are made integrally with each other by sandwiching the film up and down and continuously through the through holes of the film, and then the surface of the formed thermoplastic resin key top is made of a transparent or non-translucent thermoplastic resin. And a display section for characters, symbols, etc. By this manufacturing method, a high-quality display portion can be obtained.

Further, by providing a protective layer on the display of characters, symbols and the like on the surface of the key top portion, the display is prevented from disappearing due to wear during use.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A description will be given with reference to a schematic sectional view of a mold used in a method of manufacturing a sheet-like key top according to the present invention shown in FIG.

According to the present invention, the upper mold 7 and the lower mold 8 sandwich the flexible synthetic resin film 2 having at least one through hole 6 in the center, and the lower mold 7 is projected. A light-transmitting or non-light-transmitting thermoplastic resin is injected from a resin injection port 13 provided in the cavity a for forming a child portion. The injected thermoplastic resin passes through the through-hole 6 of the resin film, fills a cavity for forming a key top of the upper mold 7, forms a protrusion and a key top, and forms a surface of the formed key. In addition, a display portion 5 of characters, symbols, patterns, etc. is formed by screen printing or PAD printing, and a protective layer 4 is provided by painting or printing to avoid abrasion of the display portion 5, and a sheet-like sheet shown in FIG. I made a key top.

According to the present invention, since the display unit 5 is printed after the key top 1 is molded, a high quality display unit without enlargement and distortion of printed characters and symbols can be formed.

The synthetic resin film having flexibility used in the present invention includes polyester-based thermoplastic films, polyolefin-based thermoplastic films, polystyrene-based thermoplastic films, polyurethane-based thermoplastic films, polyamide-based thermoplastic films, and silicone-based thermoplastic films. The thermoplastic film is selected from a thermoplastic film, a 1,2-polybutadiene-based thermoplastic film, a polyethylene vinyl acetate-based thermoplastic film, a polyvinyl chloride-based thermoplastic film, and a polyvinyl alcohol-based thermoplastic film.

Here, the reason for using the flexible synthetic resin film is that a mechanical key switch (disc spring, polydome, contact rubber) having a click feeling is disposed below the lower surface protrusion of the sheet-like key top, The moving distance of the mechanical key switch is 0.2 mm to 1.5 mm, and the mechanism operates by depressing the sheet-like key top. Therefore, a soft material is desirable in consideration of a touch feeling and operability.

The translucent or non-translucent thermoplastic resin key top is made of polymethyl methacrylate (PMM).
A), polycarbonate (PC), acrylonitrile butadiene styrene (ABS), polypropylene (PP),
It is selected from polystyrene (PS) and the like.

The protective layer is formed by painting, screen printing,
The method of formation, such as pad printing, dropping with a dispenser or jig, is not specified.

The material of the protective layer is suitably a liquid resin, such as an acrylic resin, a urethane resin, a silicone resin, an epoxy resin, and a diallyl phthalate resin. Resin.

The protective layer has a thickness of 5 to 100.
If the thickness is smaller than 5 μm, the mechanical properties are weak, and peeling due to cracking or chipping is likely to occur. If the thickness is larger than 100 μm, the visibility of characters and symbols on the display portion is deteriorated. Preferably, the range is 15 to 50 μm.

[0015]

Embodiment 1 FIG. 3 is a schematic sectional view showing a method of manufacturing a sheet-like key top using a flexible synthetic resin film 12 provided with a plurality of through holes 16.

In the first embodiment, a sheet-like key top was manufactured in the same manner as in the first embodiment except that a plurality of through holes 16 were provided in the synthetic resin film 12 having flexibility.

The key top 11 and the protrusion 1 of the first embodiment
3 is integrated at corresponding positions of the plurality of through holes 16, so that rotation of the key top 11 can be prevented. By providing an adhesive layer on the surface of the flexible synthetic resin film 12 in advance, the flexible synthetic resin film 1
Advantageously, the adhesion between the key top 11 and the thermoplastic resin key top 11 becomes stronger.

[0018]

Second Embodiment FIG. 4 is a cross-sectional view of a surface-coated sheet-like key top according to a second embodiment.

In the second embodiment, after the translucent colored layer 15 is printed on the surface of the thermoplastic resin keytop 11 formed in the first embodiment, the entire sheet-like keytop is painted with a light-shielding paint to form a light-shielding layer. Then, the light-shielding layer 9 is removed by irradiating a laser beam in a predetermined character or symbol shape (removed portion 16), and a protective layer 4 is painted or printed on the surface thereof as a measure against abrasion of the display portion. A key top was made.

Other configurations are the same as in the first embodiment.

[0021]

Third Embodiment FIG. 5 is a cross-sectional view of a sheet-like key top in which light-shielding printing is provided on a flexible synthetic resin film of a third embodiment.

In Example 3, a flexible synthetic resin film 2 having a light-shielding printing layer 10 formed by performing light-shielding printing on the front or back surface in advance was used. Other configurations are the same as those in the first or second embodiment.

Incidentally, instead of forming the light-shielding printing layer 10, the synthetic resin film itself may be formed of a light-shielding material.

According to the sheet-like key top on which the light-shielding printing layer 10 is formed according to the third embodiment, when the height of the key top is high or the key top is adjacent to the key top, the rise of the key top occurs in the painting process. The problem of light-shielding property such as light leakage due to insufficient application of the light-shielding paint at the part can be avoided, and the light-shielding property can be enhanced.

[0025]

Fourth Embodiment FIG. 6 is a cross-sectional view of a light-colored sheet-type key top according to a fourth embodiment.

In the fourth embodiment, a translucent colored layer 5 is provided on the surface of the thermoplastic resin keytop 1 molded in the first embodiment by painting, and a light-shielding layer 9 is painted thereon with a black paint. , And then a surface colored layer 1 with a desired light-colored paint thereon.
4 is formed by painting, and the light-shielding layer 5 and the surface coloring layer 14 are simultaneously removed by irradiating a laser beam to form predetermined characters and symbols (removed portions 16).
As a measure against abrasion of the display portion, a protective layer 4 was provided by painting or printing to complete a color key top. Other configurations are the same as those of the above-described embodiment.

With the color keytops that have been completed, the color tops can be provided according to the market needs for colorization as the products become more colorized.

[0028]

According to the present invention, a display portion for characters and symbols on the surface of the key top is provided in a post-process of the thermoplastic resin molding, so that the molding quality of the thermoplastic resin reduces the print quality of characters and symbols and the like. A thin and lightweight keypad that avoids the problem of character enlargement can be realized. This is also true for key shapes that are limited due to print quality and character enlargement problems of the display portion of characters, symbols, etc., the present invention provides key shapes such as height and size, colorization, characters, symbols, etc. It is possible to provide a keypad capable of responding to a wide range of design variation needs with a high degree of design freedom for a display section such as.

Further, according to the present invention, since the key top and the projection are integrated at a plurality of locations, a sheet-like key top free from twisting rotation can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a mold used for a method of manufacturing a sheet-like keytop.

FIG. 2 is a sectional view of a sheet-like key top.

FIG. 3 is a schematic cross-sectional view of a method for manufacturing a sheet-like keytop using a flexible synthetic resin film provided with a plurality of through holes according to the first embodiment.

FIG. 4 is a cross-sectional view of a surface-coated sheet-like key top according to the second embodiment.

FIG. 5 is a cross-sectional view of a sheet-like key top in which light-shielding printing is provided on a synthetic resin film of Example 3.

FIG. 6 is a cross-sectional view of a light-colored sheet-like key top of Example 4.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Thermoplastic resin key top 2 Flexible synthetic resin film 3 Protrusion part 4 Protective layer 5 Key top surface printing layer 6 Film through hole 6 Plural provided film through holes 7 Black paint layer 8 Upper mold 9 Lower Mold 10 Flexible light-shielding printing layer of synthetic resin film 11 Light-colored coating layer 13 Resin injection port 14 Surface coloring layer

Claims (12)

[Claims] 1. An upper mold and a lower mold having at least one center in the center.
The molten resin is injected through a resin injection port provided in a cavity for forming a protrusion of a lower mold, with a flexible synthetic resin film having a plurality of through holes formed therebetween. Sheet-shaped key top that fills the cavity for forming the key top of the upper mold through the through hole of the synthetic resin film, integrally forms the protrusion and the key top, and prints the display unit on the surface of the molded key Manufacturing method. 2. The method according to claim 1, wherein the synthetic resin film has a light-shielding layer on at least one side or is of a light-shielding type. 3. The method according to claim 1, wherein a protective layer is further provided on at least the surface of the key after printing the display portion. 4. A synthetic resin film comprising a polyester thermoplastic film, a polyolefin thermoplastic film, a polystyrene thermoplastic film, a polyurethane thermoplastic film, a polyamide thermoplastic film, a silicone thermoplastic film, 4. The film according to claim 1, which is selected from at least one of a polybutadiene-based thermoplastic film, a polyethylene vinyl acetate-based thermoplastic film, a polyvinyl chloride-based thermoplastic film, and a polyvinyl alcohol-based thermoplastic film. A method for producing the sheet-like keytop according to the above. 5. An upper mold and a lower mold having at least one central part.
A transparent thermoplastic resin is injected through a resin injection port provided in a cavity for forming a presser of a lower mold by sandwiching a flexible synthetic resin film having a plurality of through holes, and the injected resin is formed. Fill the cavity for forming the key top of the upper mold through the through hole of the synthetic resin film, integrally form the protrusion and the key top, and provide a translucent colored layer on the surface of the molded key. After that, a light-shielding layer is formed on the entire surface of the key, and a surface-colored layer is further formed thereon with a desired light paint. A method for manufacturing a sheet-like key top which is removed to form a light-transmitting portion. 6. The method according to claim 3, wherein the synthetic resin film has a light-shielding layer on at least one side or is of a light-shielding type. 7. A key and a protective layer are provided on at least the surface of the key after irradiating a laser beam to simultaneously remove the light-shielding layer and the surface coloring layer into a predetermined character or symbol shape to form a light-transmitting portion. The method for producing a sheet-like keytop according to claim 5. 8. A synthetic resin film comprising a polyester thermoplastic film, a polyolefin thermoplastic film, a polystyrene thermoplastic film, a polyurethane thermoplastic film, a polyamide thermoplastic film, a silicone thermoplastic film, a 1,2- 8. The film according to claim 5, which is selected from at least one of a polybutadiene-based thermoplastic film, a polyethylene vinyl acetate-based thermoplastic film, a polyvinyl chloride-based thermoplastic film, and a polyvinyl alcohol-based thermoplastic film. A method for producing the sheet-like keytop according to the above. 9. A translucent thermoplastic resin key top and a projection are integrally formed with a flexible synthetic resin film having at least one through hole formed in the center therebetween, and the surface of the key top is formed. After forming a light-transmitting colored layer, a light-shielding layer is formed on the entire surface of the key, and a light-transmitting portion is formed by irradiating a laser beam to remove the light-shielding layer into a predetermined character or symbol shape. Top. 10. The sheet-like key top according to claim 9, wherein the synthetic resin film has a light-shielding layer on at least one surface or is a light-shielding type. 11. The sheet-like key top according to claim 9, wherein a protective layer is provided on at least the surface of the key. 12. A synthetic resin film comprising a polyester-based thermoplastic film, a polyolefin-based thermoplastic film,
Polystyrene-based thermoplastic film, polyurethane-based thermoplastic film, polyamide-based thermoplastic film, silicone-based thermoplastic film, 1,2-polybutadiene-based thermoplastic film, polyethylene vinyl acetate-based thermoplastic film, polyvinyl chloride-based thermoplastic film, or The sheet-like key top according to claim 9, 10 or 11, wherein the key top is selected from at least one of a polyvinyl alcohol-based thermoplastic film.