JPH09171738A - Key pad and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten a molding cycle by forming upper and lower cover layers each consisting of thermoplastic elastomer on the obverse and reverse of a sheet, and making the switching place of the upper cover layer a button part. SOLUTION: A plastic sheet 2 is a soft transparent or translucent sheet consisting of, for example, polyethylene terephtharate resin, and a pattern layer 3 is made as a printed layer on either side or both sides of the obverse and reverse. For the pattern layer 3, coloring ink, which contains resin capable of forming, preferably, a soft film such as, for example, polyvinyl resin, as a binder, and a pigment or a dye in proper color, as a coloring agent, is used. An upper cover layer 4 is made on the obverse of the plastic sheet 2 having the pattern layer 3, and on the reverse a lower cover layer 6 is made of transparent or translucent thermoplastic elastomer. The molding cycle can be shortened by constituting the upper cover layer 4 of a plurality of severally independent button parts 5 in the shape of upward projection.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention has an automatic button return function and an excellent design expression.
The present invention relates to a keypad that can be used in a switch section of an audio device, a home appliance, an automobile, and the like, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, many keypads made by compressing and heat-molding silicon are used for switch parts of audios, home electric appliances, automobiles and the like.

[0003]

However, since the silicon keypad is manufactured through the steps of material injection, compression / heating, curing, cooling, and removal, the molding cycle is long and it takes time to manufacture. There is a problem.

Further, since the occurrence of burrs during compression molding is related to the molding of silicon, there is a problem that deburring is essential.

Further, since the design is formed by printing after molding the silicon, there is a problem that the design is limited.
That is, when the pattern is formed by the screen printing method, the surface of the button portion of the silicon keypad, which is the surface to be printed, is a curved surface, and therefore the pattern is limited because it is difficult to print. Further, when the pattern is formed by the coating method, the pattern is limited because the color tone is simple and the equipment is difficult. In addition, when applying a coating after screen printing and finally removing the ink film of unnecessary parts by laser etching to form a pattern, the coating is black because of the laser etching method and the pattern is limited, and the cost is high. But also.

Further, since the design is provided on the silicon keypad and is printed on the part which is touched as a keypad, there is a problem that the wear resistance of the design is not good.

Further, since silicon is a material having a small surface tension and poor adhesion, it is a special type of ink that is strongly adhered, and heat treatment is required at a high temperature of about 60 to 220 ° C., preferably 100 to 150 ° C. after printing. There is a problem.

There is also a problem that the oil resistance is poor.

Therefore, it is an object of the present invention to provide a keypad which eliminates the above-mentioned drawbacks, has a beautiful design effect, and has an automatic return function of a button portion, and a manufacturing method thereof.

[0010]

SUMMARY OF THE INVENTION A keypad and a method of manufacturing the same according to the present invention are configured as follows to achieve the above object.

That is, in the keypad of the present invention, an upper coating layer made of a transparent or semitransparent thermoplastic elastomer is formed on the surface of a flexible, transparent or translucent plastic sheet having a pattern layer, and a transparent or translucent plastic sheet is formed on the back surface. A lower coating layer made of a translucent thermoplastic elastomer was formed, and a switching portion of the upper coating layer was formed as a button portion.

In the above invention, the upper coating layer may be composed of a flat plate.

In the above invention, the upper coating layer may be composed of a plurality of independent upwardly convex button portions.

In the above invention, the upper coating layer may be composed of a plurality of upwardly convex button portions and a flat plate connecting the bottom portions of the button portions.

In the above invention, the lower coating layer may be a flat plate.

In the above invention, the lower coating layer may be composed of a plurality of independently projecting portions each having a downward convex shape at a position corresponding to the button portion.

In the above invention, the lower coating layer may be composed of a plurality of downwardly projecting projections at a position corresponding to the button portion and a flat plate connecting the bottoms of the projections.

In the above invention, the thickness of the upper coating layer around the button portion may be thinner than other portions.

In the above invention, the thickness of the lower layer covering portion around the protrusion may be smaller than that of the other portions.

The method of manufacturing a keypad according to the present invention further comprises forming an upper coating layer made of a transparent or translucent thermoplastic elastomer on the surface of a flexible, transparent or translucent plastic sheet having a pattern layer, and forming a back surface. A lower coating layer made of a transparent or translucent thermoplastic elastomer was formed on the above, and the switching portion of the upper coating layer was formed as a button portion.

In the above invention, the upper coating layer may be formed as a flat plate.

In the above invention, the upper coating layer may be formed by a plurality of button portions each having an upward convex shape and independent of each other.

In the above invention, the upper coating layer may be formed by a plurality of upwardly convex button portions and a flat plate connecting the bottom portions of the button portions.

In the above invention, the lower coating layer may be formed as a flat plate.

In the above invention, the lower coating layer may be formed in a plurality of independent protruding portions each having a downward convex shape at a position corresponding to the button portion.

In the above invention, the lower coating layer may be formed by a flat plate connecting a plurality of downwardly projecting projections and bottoms of the projections at locations corresponding to the button portions.

In the above invention, the thickness of the upper coating layer around the button portion may be made thinner than the other portions.

In the above invention, the lower layer covering portion may be formed so that the thickness around the protruding portion is thinner than other portions.

In the above invention, at least one of the upper coating layer and the lower coating portion may be formed by injection molding.

[0030]

Embodiments of the present invention will be described in detail with reference to the drawings.

1 to 8 are sectional views showing an embodiment of the keypad of the present invention. In the figure, 1 is a keypad, 2 is a plastic sheet, 3 is a design layer, 4 is an upper coating layer, 5
Is a button portion, 6 is a lower coating layer, and 7 is a protruding portion.

The keypad 1 has a pattern layer 3 and a flexible, transparent or translucent plastic sheet 2 on which an upper coating layer 4 made of a transparent or translucent thermoplastic elastomer is formed, and on the back surface thereof is transparent or translucent. The lower coating layer 6 made of a transparent thermoplastic elastomer is formed, and the switching portion of the upper coating layer 4 is the button portion 5 (see FIG. 1).

The plastic sheet 2 is a flexible transparent or translucent material, and specifically, polyethylene terephthalate, polypropylene, nylon, vinylon, polycarbonate, polybutylene terephthalate, vinyl chloride, polyethylene, polyamide, polyurethane, acrylic, etc. It is preferable to use a sheet made of the above resin.

The reason why the plastic sheet 2 needs to be flexible is that when the keypad 1 is pressed, the elastomer is not deformed and peeling or wrinkling occurs. Moreover, when the plastic sheet 2 is on the surface, there is a problem that nails, scratches, wrinkles, and dents occur. Specifically, the term “flexible” means that plastic deformation does not easily occur even if deformation such as pressing or bending is applied, and that there are few dents, sags, and wrinkles due to bending. The term “transparent or translucent” specifically means that visible light is excellently transmitted, and the printed pattern is not hidden when viewed through a sheet.

The pattern layer 3 may be formed by printing a pattern on either one surface or both surfaces of the plastic sheet 2. Therefore, the keypad 1
In order to prevent peeling between the plastic sheet 2 and the upper coating layer 4 or between the plastic sheet 2 and the lower coating layer 6 due to deformation of the elastomer or the like when pressing, the pattern layer 3 is formed on both sides. On the other hand, it must have excellent adhesion. Further, the pattern layer 3 may have a concealing portion and a light transmitting portion. By forming the design layer 3 in this way, it is possible to obtain a translucent keypad 1 configured to emit numbers and the like when a light source is arranged on the back surface.

The pattern layer 3 is usually formed as a printing layer. As the material of the printing layer, polyvinyl resin, polyamide resin, polyester resin, acrylic resin, polyurethane resin, polyvinyl acetal resin, polyester urethane resin, cellulose ester resin,
It is preferable to use a coloring ink containing a resin such as an alkyd resin or a thermoplastic elastomer, preferably a resin capable of forming a flexible film, as a binder and a pigment or dye of an appropriate color as a coloring agent. As a method for forming the printing layer, a normal printing method such as an offset printing method, a gravure printing method, or a screen printing method may be used. In particular, an offset printing method or a gravure printing method is suitable for performing multicolor printing and gradation expression. In the case of a single color, a coating method such as a gravure coating method, a roll coating method, and a comma coating method can be adopted. The printing layer may be provided entirely or partially depending on the design to be expressed.

The pattern layer 3 may be composed of a metal thin film layer or a combination of a printed layer and a metal thin film layer. The metal thin film layer is for expressing metallic luster as the pattern layer 3, and is formed by a vacuum deposition method, a sputtering method, an ion plating method, a plating method, or the like. Metals such as aluminum, nickel, gold, platinum, chromium, iron, copper, tin, indium, silver, titanium, lead, and zinc, and alloys or compounds thereof are used according to the metallic luster color to be expressed. As an example of forming a partial metal thin film layer, after forming a solvent-soluble resin layer in a portion that does not require a metal thin film layer, a metal thin film is entirely formed thereon, and solvent cleaning is performed. There is a method of removing an unnecessary metal thin film together with the solvent-soluble resin layer. The solvent often used in this case is water or an aqueous solution. As another example, there is a method in which a metal thin film is formed on the entire surface, a resist layer is formed on a portion where the metal thin film is to be left, and the resist layer is removed by etching with an acid or alkali. .

An adhesive layer may be provided on one side or both sides of the plastic sheet 2 in order to improve the adhesion with the upper coating layer 4 or the lower coating layer 6 which will be formed later. The adhesive layer may be provided on the design layer 3 or on the plastic sheet 2 in some cases. As the adhesive layer, a heat-sensitive or pressure-sensitive resin suitable for the material of the thermoplastic elastomer is appropriately used. For example, when the thermoplastic elastomer material is a polyester elastomer, a polyester resin or an epoxy resin may be used. When the thermoplastic elastomer is made of urethane resin, styrene resin, polyester resin, or vinyl chloride resin, polyamide resin having an affinity for these resins may be used. When the material of the thermoplastic elastomer is polypropylene resin, chlorinated polyolefin resin, chlorinated ethylene-vinyl acetate copolymer resin, cyclized rubber and coumarone indene resin can be used. As a method for forming the adhesive layer, a coating method such as a gravure coating method, a roll coating method, a comma coating method,
There are printing methods such as a gravure printing method and a screen printing method.

As described above, the upper layer coating layer 4 is formed on the front surface of the plastic sheet 2 having the pattern layer 3, and the lower layer coating layer 6 is formed on the back surface. Upper coating layer 4 and lower coating layer 6
Is formed of a transparent or translucent thermoplastic elastomer.

A transparent or translucent thermoplastic elastomer is used. Specifically, a styrene-based, urethane-based, polyester-based, olefin-based, or polyamide-based thermoplastic elastomer may be used. The reason why the thermoplastic elastomer needs to be transparent or translucent is to see through the pattern layer 3 or to transmit light to the transparent portion of the pattern layer 3.

The shape of the upper coating layer 4 is a flat plate (see FIGS. 7 and 8), a plurality of independent upwardly convex button portions 5 (see FIGS. 1, 2 and 3), and upward facing. It may be any of a plurality of convex button portions 5 and a flat plate connecting the bottom portions of the button portions 5 (see FIGS. 4, 5 and 6). The shape of the lower coating layer 6 is
Flat plate (see FIGS. 1 and 4), having a plurality of independent downwardly projecting protrusions 7 at locations corresponding to the button portion 5 (see FIGS. 2, 5 and 7), corresponding to the button portion 5 Any of those having a plurality of downwardly projecting protrusions 7 and a flat plate connecting the bottoms of the protrusions 7 at the positions (see FIGS. 3, 6, and 8) may be used. The button portion 5 and the protruding portion 7 may have the same shape as the button portion and the protruding portion of the conventional keypad.

Further, the thickness of the upper coating layer 4 around the button portion 5 is formed thinner than the other portions so that when the button portion 5 is pushed, it moves easily, and when the button portion 5 is released, the shape is easily changed. It may be restored (not shown). For the same reason, the thickness of the lower cover portion around the protrusion 7 may be formed thinner than other portions (not shown).

The method for providing the upper coating layer 4 and the lower coating layer 6 includes injection molding, compression molding, extrusion molding, blow molding, calendar molding, transfer molding and the like, preferably injection molding. Is. When the injection molding method is adopted, the pattern of the design layer 3 and the concave portion of the mold are aligned with the injection mold, and insert molding can be performed. In the insert molding method, the plastic sheet 2 is supplied into an injection molding die, and the upper coating layer 4
And a method in which the plastic sheet 2 is integrally attached to the upper coating layer 4 and the lower coating layer 6 simultaneously with the molding of the lower coating layer 6. With the insert molding method, the plastic sheet 2 can be attached at the same time as molding in the mold,
The manufacturing process can be greatly simplified. Further, since the plastic sheet 2 is stretched by the injection pressure of the molten resin and follows the mold, there is an advantage that the three-dimensional keypad 1 can be easily obtained.

First, the plastic sheet 2 is fed into a molding die including a movable die and a fixed die. The individual plastic sheets 2 that have been cut or preformed in a desired shape in advance may be fed one by one, or necessary portions of the long plastic sheet 2 may be intermittently fed. When a long plastic sheet 2 is used, it is preferable to use a feeder having a positioning mechanism so that the register between the design layer 3 of the plastic sheet 2 and the molding die coincides with each other. Further, when the plastic sheet 2 is intermittently fed, if the position of the plastic sheet 2 is detected by a sensor and then the plastic sheet 2 is fixed by a movable die and a fixed die, the plastic sheet 2 is always in the same position. It is convenient because it can be fixed and the pattern layer 3 is not displaced. Here, the plastic sheet 2 may be heated so that the plastic sheet 2 can easily follow the mold. For heating, an infrared heater, a nichrome heater or the like may be arranged near the plastic sheet 2.

After closing the molding die, the molten resin is injected and filled into the die from the gate provided in the fixed die to form the upper coating layer 4 or the lower coating layer 6, and at the same time, the plastic sheet 2 is bonded. To do. As the molten resin, the above-mentioned thermoplastic elastomer is used.

After cooling the molded product, the molding die is opened and the molded product of the plastic sheet 2 is taken out to complete the insert molding, whereby the keypad 1 can be obtained. In addition,
When the long plastic sheet 2 is used, since the plastic sheet 2 is integrated with the keypad 1, trimming on the outer periphery of the keypad 1 is necessary before taking out from the mold.

Further, the upper coating layer 4 and the lower coating layer 6 may be simultaneously provided on both surfaces of the plastic sheet 2 by the injection molding method. Further, the upper coating layer 4 and the lower coating layer 6 may be provided on each side of the plastic sheet 2. First, either one of the upper coating layer 4 and the lower coating layer 6 is provided on one side of the plastic sheet 2, taken out from the mold and inserted into another mold, and the other coating layer is injected on the other side of the plastic sheet 2. It may be formed by molding. When the button portion 5 or the protruding portion 7 is not connected by a flat plate and is independent of each other, it is necessary to provide the injection mold with a gate corresponding to each button portion 5 or the protruding portion 7.

[0048]

EXAMPLE A pattern layer was printed on a back surface of a polyester film having a thickness of 75 μm using a color ink containing 95% by weight of a polyester-based ink and 5% by weight of a curing agent so as to form a blank character pattern. Provided on the entire surface. An epoxy adhesive layer was also provided on the surface of the plastic sheet.

The rear surface of the plastic sheet is arranged so as to be in contact with the surface of the first mold cavity, and together with the concave core surface, the polyester elastomer is injected from the side gates, and the upper coating layer has a plurality of upward convex shapes. Was formed so as to include a button portion and a flat plate connecting the bottom portion of the button portion.

Next, the button portion is fitted into the concave portion of the surface of the second mold cavity, combined with the second mold core, and the polyester elastomer is injected from the respective pin gates corresponding to the voids to be the protrusions of the lower layer coating portion. Molded and provided with protrusions.

The keypad thus obtained has an automatic resetting function, has an excellent design effect, and has an LED inside.
It has an excellent performance of having a button portion that shields the light of the above from the blank character pattern of the concealed portion.

[0052]

Since the present invention has the above-described structure, it has the following effects.

The keypad manufacturing method of the present invention comprises a flexible, transparent or translucent plastic sheet having a pattern layer, an upper coating layer made of a transparent or translucent thermoplastic elastomer formed on the surface, and a transparent back surface. Alternatively, the lower coating layer made of a translucent thermoplastic elastomer is formed and the switching portion of the upper coating layer is used as the button portion, so that the molding cycle is short.

In the keypad of the present invention, the upper coating layer and the lower coating layer are made of thermoplastic elastomer,
Since silicon is not used for the button portion and the protruding portion, burrs do not occur, and it has excellent durability.
Also, because the design is formed on the plastic sheet,
The design is not limited and excellent design expression is possible. Further, since the design is sandwiched between the upper coating layer and the lower coating layer, the wear resistance of the design is excellent.

Also, a plastic sheet, an upper coating layer,
Since all of the lower coating layers are transparent or translucent,
A translucent keypad is easily obtained. Further, since all of the plastic sheet, the upper coating layer and the lower coating layer have flexibility, a flexible keypad having an automatic return function can be easily obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a keypad of the present invention.

FIG. 2 is a sectional view showing an embodiment of the keypad of the present invention.

FIG. 3 is a sectional view showing an embodiment of the keypad of the present invention.

FIG. 4 is a sectional view showing an embodiment of a keypad of the present invention.

FIG. 5 is a sectional view showing an embodiment of the keypad of the present invention.

FIG. 6 is a sectional view showing an embodiment of the keypad of the present invention.

FIG. 7 is a sectional view showing an embodiment of the keypad of the present invention.

FIG. 8 is a sectional view showing an embodiment of the keypad of the present invention.

[Explanation of symbols]

 1 keypad 2 plastic sheet 3 design layer 4 upper layer coating layer 5 button part 6 lower layer coating layer 7 protruding part

Claims (19)

[Claims] 1. An upper coating layer made of a transparent or translucent thermoplastic elastomer is formed on the surface of a flexible, transparent or translucent plastic sheet having a pattern layer, and a transparent or translucent thermoplastic elastomer is formed on the back surface. A keypad having a lower coating layer formed thereon and a switching portion of the upper coating layer serving as a button portion. 2. The keypad according to claim 1, wherein the upper coating layer is a flat plate. 3. The keypad according to claim 1, wherein the upper coating layer comprises a plurality of independent button portions each having an upward convex shape. 4. The keypad according to claim 1, wherein the upper coating layer comprises a plurality of upwardly convex button portions and a flat plate connecting the bottom portions of the button portions. 5. The keypad according to claim 1, wherein the lower coating layer is a flat plate. 6. The keypad according to any one of claims 1 to 4, wherein the lower coating layer comprises a plurality of independent protruding portions each having a downward convex shape at a position corresponding to the button portion. 7. The keypad according to claim 1, wherein the lower coating layer comprises a plurality of downwardly projecting protrusions at a location corresponding to the button portion and a flat plate connecting the bottoms of the protrusions. . 8. The keypad according to claim 1, wherein the thickness of the upper coating layer around the button portion is thinner than other portions. 9. The keypad according to claim 1, wherein the thickness of the lower layer covering portion around the protruding portion is thinner than the other portions. 10. An upper coating layer made of a transparent or translucent thermoplastic elastomer is formed on the surface of a flexible, transparent or translucent plastic sheet having a pattern layer, and a transparent or translucent thermoplastic elastomer is formed on the back surface. A method for manufacturing a keypad, wherein a lower coating layer is formed, and a switching portion of the upper coating layer is used as a button portion. 11. The upper coating layer is formed as a flat plate.
0. The manufacturing method of the keypad described in 0. 12. The method of manufacturing a keypad according to claim 10, wherein the upper coating layer is formed of a plurality of independent button portions each having an upward convex shape. 13. The method of manufacturing a keypad according to claim 10, wherein the upper coating layer is formed by a plurality of upwardly convex button portions and a flat plate connecting the bottom portions of the button portions. 14. The lower coating layer is formed as a flat plate.
The method for manufacturing the keypad according to any one of 0 to 13. 15. The method of manufacturing a keypad according to claim 10, wherein the lower coating layer is formed in a plurality of independent protruding portions each having a downward convex shape at a position corresponding to the button portion. 16. The keypad according to claim 10, wherein the lower coating layer is formed of a flat plate connecting a plurality of downwardly projecting projections and bottoms of the projections at locations corresponding to the button portions. Production method. 17. The thickness of the periphery of the button portion of the upper coating layer is formed thinner than other portions.
A method for manufacturing a keypad according to any one of 1. 18. The method for manufacturing a keypad according to claim 10, wherein a thickness of the lower layer covering portion around the protruding portion is formed thinner than other portions. 19. The method of manufacturing a keypad according to claim 10, wherein at least one of the upper coating layer and the lower coating portion is formed by an injection molding method.