JP2002175738A - Decorated key top - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a decorated key top superior in appearance having iridescence by a diffraction grating. SOLUTION: In this decorated key top having iridescence, the diffraction grating 7 which is a metal mold transfer layer is formed in a surface and/or a rear face of a resin key top 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-quality decorative key top which is used for mobile phones, portable information terminals, remote controllers for various home appliances, card remote controllers, and various keyboards. .

[0002]

2. Description of the Related Art Conventionally, as a method of decorating a key top portion of a push button switch with a metallic gloss or a pearl gloss,
There are a method of dispersing a metal powder and a pearl pigment in a resin and a rubber of the key top, and a method of providing a layer of a metallic gloss or a pearl gloss on the surface of the key top. The latter method of providing a layer on the surface of the key top includes a method of providing a coating layer by a screen printing method or a spray coating method with a paint containing metal powder or pearl pigment, a vacuum evaporation method of aluminum or chromium, or a sputtering method. For example, there is known a method of providing a metal thin film layer by nickel plating or the like, a method of providing a plating layer by electroless plating or electrolytic plating of nickel or chromium, or the like. For resin key tops incorporated in push button switches of recent mobile phones, mobile terminal devices, remote controllers for various home appliances, card remote controllers, and various keyboards, there is an extremely high demand for a beautiful, high-quality iris-colored luster. Is getting stronger.

[0003]

However, the method of dispersing a metal powder or a pearl pigment in a resin or a rubber of a key top is difficult to uniformly disperse the metal powder or the pearl pigment. There have been problems such as the occurrence of striped patterns and uneven color tone, making characters and symbols difficult to see. Also, in the method of providing a layer on the surface of the key top, a coating layer using a paint containing a metal powder or a pearl pigment does not have a uniform and high-quality iris luster. Although the metal thin film layer or the plating layer using No. 1 exhibited metallic luster, it did not have iris luster.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems and provides a decorative key top having an iris gloss by a diffraction grating and having an excellent appearance. That is, it is a decorative keytop having an iris luster in which a diffraction grating is formed on the front surface and / or the back surface of the resin keytop. Further, the diffraction grating is a decorative keytop which is a mold transfer layer. Further, the diffraction grating is a decorative key top which is a transfer layer of a film having a diffraction grating structure. Furthermore, the decorative key top is provided with an inorganic thin film layer made of an inorganic material or a polymer layer made of a polymer material in which inorganic powder is dispersed on the back surface of the diffraction grating.

[0005] The diffraction grating of the present invention is obtained by engraving a large number of grooves on the same surface at substantially equal intervals. For example, FIG.
The enlarged view from the top as shown in FIG.
A groove serving as a lattice line group or a concentric line group may be used. The presence of materials having different refractive indexes through the surface of the diffraction grating causes iris gloss.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. A decorative key top according to a typical embodiment of the present invention is such that a diffraction grating is formed on a front surface and / or a back surface of a molded resin key top by die transfer, and a back surface side of the diffraction grating is formed of an inorganic material. A decorative keytop having an iris-like gloss provided with an inorganic thin film layer or a polymer layer made of a polymer material in which an inorganic powder is dispersed. For example, as shown in FIG. 1, an iris color in which a diffraction grating is formed on the back surface of a resin keytop 1 molded by a mold having a diffraction grating, and an inorganic thin film layer 2 made of an inorganic substance is provided on the back surface of the diffraction grating. Decorated key tops having luster are exemplified.

Alternatively, as shown in FIG. 2, a diffraction grating transfer thin film 7 made of a liquid resin or a paint on which a diffraction grating structure is transferred is formed on the back surface of the resin key top 1, and an inorganic powder is further applied on the back surface. A decorative keytop having an iris gloss provided with a polymer layer 6 made of a dispersed polymer material is exemplified.

Alternatively, as shown in FIG. 3, a diffraction grating transfer thin film 7 made of a liquid resin or paint having a diffraction grating structure transferred on the surface of a resin key top 1 and an inorganic thin film layer 2 made of an inorganic material on the back surface. A decorative key top having an iris luster provided with a thermoplastic adhesive 8 is used.

Alternatively, as shown in FIG. 4, a diffraction grating transfer thin film 7 made of a liquid resin or paint having a diffraction grating structure transferred thereon is formed on the surface of the resin key top 1, and further, on the back surface of the resin key top 1, A decorative keytop having an iris gloss provided with a polymer layer 6 made of a polymer material in which an inorganic powder is dispersed is exemplified. FIGS. 1 to 4 show a push button switch in which a base member 5 made of a rubber-like elastic body is provided on the back surface of the decorative key top with an adhesive layer 4 interposed therebetween. The configuration using the top is not limited to this mode.

[0010] The decorative key top of the present invention has an iris gloss by forming a diffraction grating on the surface and / or the back surface of the key top made of resin. Although there is no particular limitation on the uneven shape of the cross section of the diffraction grating, for example, there is a shape in which the cross section is formed by a repetitive pattern of saw-toothed unevenness. The height of the irregularities is usually 0.2 μm to 3
μm, particularly preferably 0.5 to 1 μm, and its width (period).
Is usually 0.05 to 3 μm, particularly preferably 0.1 to 1 μm.

The formation of the diffraction grating on the front surface and / or the back surface of the resin key top is performed at an appropriate stage. For example,
A method of forming a thermoplastic polymer coating film on the front and / or back surface of the molded resin key top, embossing and transferring using the uneven pattern of the diffraction grating in the mold, and diffracting in the cavity. There is a method of molding a resin key top using an injection mold having a lattice pattern.
Alternatively, after applying an uncured liquid resin or paint to the front or back surface of the resin key top, a film having a diffraction grating structure is overlaid and pressed, and after further curing the liquid resin or paint, the film is peeled off. There is a method of transferring the unevenness of the diffraction grating.

The method of forming the pattern of the diffraction grating on the mold is not particularly limited, but a method of directly forming a concavo-convex pattern by fine electric discharge machining, mechanical engraving, or the like, and a method of forming a metal plate coated with a photoresist in advance. After forming a concavo-convex pattern by electron beam drawing, there is a method of conducting a treatment such as vacuum evaporation, a method of transferring a structure by electrolytic plating, and then removing a metal plate.

The resin keytop used in the present invention is a resin keytop formed by molding or a resin keytop obtained by reacting and curing an uncured liquid resin. More specifically, using a mold of a desired key top shape, injection molding,
It can be manufactured by filling a mold with a resin or a liquid uncured resin heated and melted by compression molding, transfer molding, rotational molding or the like, and then solidifying the resin.

Although there is no particular limitation on the composition and type of the resin, the elastic modulus and the color tone, polymethyl methacrylate, polycarbonate, silicone resin, amorphous polyester, polyvinyl chloride, polystyrene, polyarylate, amorphous polyolefin, etc. Particularly preferred are polymethylpentene, amorphous nylon, polyurethane, polyester-based thermoplastic elastomer, styrene-based thermoplastic elastomer, and nylon-based thermoplastic elastomer. Polyethylene, polypropylene, acrylonitrile butadiene styrene resin, crystalline polyester such as polyethylene terephthalate and polybutylene terephthalate, crystalline nylon, polyphenylene ether, polyacetal, polyacetal, polysulfone, polyether sulfone, polyphenylene sulfide, polyimide, polyether, polyketone, poly Translucent or slightly colored resins such as ether ketone, polyether ether ketone, polyether nitrile, polyether imide, liquid crystal polymer, and fluororesin may be used.
In addition, thermosetting, photo-curing, such as silicone resin, epoxy resin, phenol resin, unsaturated polyester, diallyl phthalate, acrylic resin, urethane resin, etc.
It is also possible to use a resin such as a moisture-curable resin.

These resin key tops are attached to a base member of a push button switch formed of a synthetic rubber such as silicone rubber or ethylene propylene rubber or a thermoplastic elastomer with an adhesive or a double-sided tape to form a push button switch structure. be able to. Further, a resin key top structure formed by two-color molding of a thermoplastic elastomer and a hard resin, or a different thermoplastic elastomer is also included.
Further, a base member made of a resin film can be used.

The present invention is a decorative key top provided with an inorganic thin film layer made of an inorganic substance or a polymer layer made of a polymer material in which inorganic powder is dispersed, on the back side of the diffraction grating. The inorganic substance that can be used in the present invention is a metal selected from titanium, magnesium, tungsten, aluminum, chromium, cobalt, tin, nickel, zinc, gold, silver, and platinum, or titanium oxide, silicon oxide, iron oxide, and oxide. Magnesium, tungsten oxide, aluminum oxide, chromium oxide, cobalt oxide, tantalum oxide, indium oxide, tin oxide, nickel oxide, manganese oxide, zirconium oxide, vanadium oxide, cerium oxide, bismuth oxide, antimony oxide, zinc oxide, hafnium oxide, It is preferably any one of metal compounds selected from silicon nitride, aluminum nitride, titanium nitride, magnesium fluoride, cerium fluoride, lead fluoride, silicon carbide, titanium carbide, and zinc sulfide. In the case where the inorganic thin film layer and the polymer layer have a light-transmitting property, a light-transmitting decorative key top and a push button switch can be obtained.

The method of forming the inorganic thin film layer made of an inorganic material includes, for example, a vapor deposition method, a plating method, a foil transfer method and the like. Examples of a method for forming a polymer layer made of a polymer material in which an inorganic powder is dispersed include printing and application of a paint made of a polymer material in which an inorganic powder is dispersed. Hereinafter, the present invention will be described specifically with reference to Examples and Comparative Examples. However, the present invention is not limited to the following examples.

[0018]

Embodiment 1 FIG. 5 is a longitudinal sectional view of an injection mold for molding a resin key top according to Embodiment 1 of the present invention. A diffraction grating metal plate 10 having a fine concavo-convex pattern of the diffraction grating is fixed to the mold body 9 with fixing screws 11 so that the pattern faces the cavity 13. FIG. 6A is an enlarged view of a pattern of the diffraction grating metal plate, and FIG. 7 is a longitudinal sectional view of a fine uneven pattern of the diffraction grating metal plate. Cross section is 3μ groove interval
A diffraction grating metal plate 2 was used in which a fine uneven pattern formed of a group of parallel lines having a sawtooth shape with a groove depth of 1 μm was machined.

FIG. 1 is a vertical sectional view of a push button switch provided with a decorative key top. Polycarbonate (Panlite L1225L manufactured by Teijin Chemicals Ltd.) was injection-molded using the above-mentioned mold to produce a polycarbonate resin keytop 1 having a fine uneven pattern of a diffraction grating on the back surface. Furthermore, washed back surface of the resin key top with ethanol, in a vacuum evaporation apparatus, a bell jar internal pressure 5 × 10 ^{- 4} torr, deposition rate of 5 nm / min for 10 min, aluminum was vacuum-evaporated to a thickness of 50nm Then, an inorganic thin film layer 2 made of aluminum having a total light transmittance of 90% was formed, and a decorative key top having an iris color gloss of a diffraction grating was obtained.

Further, an acrylic urethane-based ink was screen-printed on the back surface of the inorganic thin film layer 2 to form a protective print layer 3. A base member 5 made of transparent silicone rubber is attached to the protective printing surface of the resin keytop via a thermosetting silicone-based adhesive layer 4 to obtain a pushbutton switch provided with a decorative keytop having an iris color. Was.

[0021]

Embodiment 2 FIG. 2 is a vertical sectional view of a push button switch provided with a resin key top according to Embodiment 2 of the present invention. Using a mold, polycarbonate (Iupilon H-3000R)
(Mitsubishi Engineering Plastics) was injection molded to produce a resin key top 1 having a smooth back surface. Further, after applying an ultraviolet curable acrylic paint to the back surface of the resin key top 1, a film having a diffraction grating structure was repeatedly pressed and cured by ultraviolet rays. Thereafter, the film was peeled off to form a diffraction grating transfer thin film 7 to which a fine uneven pattern was transferred.

Further, a high-brightness reflective acrylic ink in which aluminum fine powder was dispersed was screen-printed to form a polymer layer 6 to obtain a decorative key top.
A base member 5 made of transparent silicone rubber is attached to the protective printing surface of the resin keytop via a thermosetting silicone-based adhesive layer 4 to obtain a pushbutton switch provided with a decorative keytop having an iris color. Was.

[0023]

Third Embodiment FIG. 3 is a longitudinal sectional view of a push button switch provided with a resin key top according to a third embodiment of the present invention. First, after applying a thermosetting acrylic paint on the release sheet,
The paint surface was overlaid and pressed against a mold having a diffraction grating structure, heated and cured, and then peeled off from the mold to form a diffraction grating transfer thin film 7 on which a fine uneven pattern was transferred. Further, in a vacuum deposition apparatus, aluminum was vacuum-deposited at a bell jar internal pressure of 5 × 10 ⁻⁴ torr and a film formation rate of 5 nm / min for 10 minutes to form an inorganic film made of aluminum having a thickness of 50 nm and a total light transmittance of 90%. The thin film layer 2 was formed, and the thermoplastic adhesive 8 was further applied thereto to prepare a thermal transfer sheet.

Next, polycarbonate (Iupilon H-3000R manufactured by Mitsubishi Engineering-Plastics Co., Ltd.) was injection-molded using a mold to produce a resin key top 1. The thermal transfer sheet prepared above was superposed on the surface of the resin key top 1 so as to face each other, and the laminate of the diffraction grating transfer thin film 7 and the inorganic thin film layer 2 was transferred by a hot stamping method. The resin keytop was peeled off from the release sheet, and a decorative keytop having an iris color tone gloss of the diffraction grating was obtained in which the laminated layer of the diffraction grating transfer thin film 7 and the inorganic thin film layer 2 was transferred only to the top surface of the resin keytop. Further, a base member 5 made of transparent silicone rubber was adhered through a thermosetting silicone-based adhesive layer 4 to obtain a push button switch provided with a decorative key top having an iris color.

[0025]

Embodiment 4 FIG. 4 is a longitudinal sectional view of a push button switch provided with a resin key top according to Embodiment 4 of the present invention. Using a mold, polycarbonate (Iupilon H-3000R)
A resin key top 1 was produced by injection molding of Mitsubishi Engineering Plastics. Furthermore, after applying an ultraviolet curable acrylic paint on the surface of the resin key top 1, a film having a diffraction grating structure is overlaid and pressed,
It was further cured by ultraviolet light. After this, peel off the film,
The diffraction grating transfer thin film 7 to which the fine concavo-convex pattern was transferred was formed.

Further, a polymer layer 6 is formed on the back surface of the resin key top 1 by screen printing a high-brightness reflective acrylic ink in which aluminum fine powder is dispersed, and an acrylic urethane is formed on the back surface of the polymer layer 6. The protective printing layer 3 was formed by screen printing of the system ink, and a decorative key top having an iris color tone gloss of the diffraction grating was obtained. A base member 5 made of transparent silicone rubber is attached to the protective printing surface of the resin keytop via a thermosetting silicone-based adhesive layer 4 to obtain a pushbutton switch provided with a decorative keytop having an iris color. Was.

[0027]

According to the present invention, by providing a diffraction grating structure on the front surface and / or the back surface of the resin key top, it is possible to obtain an iris-colored luster, which has not been obtained conventionally, and has a high-quality appearance. A decorative key top and a push button switch provided with the decorative key top can be provided.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view of a push button switch provided with a decorative key top according to a first embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of a push button switch provided with a decorative key top according to a second embodiment of the present invention.

FIG. 3 is a longitudinal sectional view of a push button switch provided with a decorative key top according to a third embodiment of the present invention.

FIG. 4 is a vertical sectional view of a push button switch provided with a decorative key top according to a fourth embodiment of the present invention.

FIG. 5 is a longitudinal sectional view of an injection mold for molding a resin key top according to the first embodiment of the present invention.

FIG. 6 is an enlarged view showing a pattern example of the diffraction grating of the present invention.

FIG. 7 is a longitudinal sectional view of the diffraction grating metal plate according to the first embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Resin keytop 2 Inorganic thin film layer 3 Protective printing layer 4 Base member 5 Adhesive layer 6 Polymer layer 7 Diffraction grating transfer thin film 8 Thermoplastic adhesive 9 Mold main body 10 Diffraction grating metal plate 11 Fixing screw 12 Gate 13 Cavity

Claims (4)

[Claims] 1. A decorative key top having an iris luster, wherein a diffraction grating is formed on the front surface and / or the back surface of the resin key top. 2. The decorative key top according to claim 1, wherein the diffraction grating is a mold transfer layer. 3. The decorative key top according to claim 1, wherein the diffraction grating is a transfer layer of a film having a diffraction grating structure. 4. The method according to claim 1, wherein an inorganic thin film layer made of an inorganic material or a polymer layer made of a polymer material in which inorganic powder is dispersed is provided on the back surface of the diffraction grating. The decorative key top according to claim 3.