JP3514576B2 - Keypad manufacturing method and keypad - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a keypad used in a switch section of audio equipment, mobile phones, home appliances, automobiles, etc.

[0002]

2. Description of the Related Art A translucent button is one of the key buttons incorporated in a surface panel of an audio device, a mobile phone, a home electric appliance, an automobile, etc. and functioning as a switch button. A translucent button is a button made of transparent resin with a decorative part that displays characters, figures, etc. formed on the front or back of the button. , Letters, figures, etc. appear to shine partially,
In addition to the function as a switch button, it has an excellent display function and an excellent design effect. By the way, in most cases, a plurality of translucent buttons are provided on the front panel, and these translucent buttons are formed by adhering in advance in a desired arrangement on a sheet made of an elastomer resin. I have something to do. In this way, a plurality of translucent buttons bonded to an elastomer resin sheet is called a keypad. Since the key buttons are adhered to the keypad in a desired arrangement in advance, it is effective in that the work of arranging the key buttons when assembling the front panel can be omitted. Also, since it is a sheet, it can exert a waterproof function. Furthermore, by using an elastomer resin,
When the key button is pressed, a soft click feeling and a restoration function can be exhibited.

In the conventional keypad manufacturing method, a step of manufacturing key buttons, a step of arranging the key buttons at desired positions, a step of adhering the key buttons on an elastomer resin sheet, and a decorative portion on the surface of the key buttons. The forming process was performed separately. For example, JP-A-5-347112
The following manufacturing method is shown in the issue. First, a translucent button is formed by a molding method using a translucent material. next,
A translucent button is attached to the insert portion formed in a fixed die in the elastomer die in a predetermined arrangement with the back side facing the inside of the cavity (see FIG. 23). Next, while supplying the elastomer material, the elastomer resin sheet is integrally compression-molded with the translucent button by heating and pressurizing with the movable die of the elastomer die (see FIG. 24). After cooling, the elastomer resin sheet integrated with the translucent button is taken out of the mold, and a decorative portion including a display portion and a non-display portion is formed on the surface of the translucent button (see FIG. 25). Examples of the decorating method include chemicolor treatment, screen printing, laser marking treatment after painting, and plating treatment.

[0004]

In the conventional keypad manufacturing method, the steps of manufacturing the key buttons, the steps of arranging the key buttons at desired positions, the steps of adhering the key buttons on the elastomer resin sheet, and the key buttons. The step of forming the decorative portion on the surface was performed separately, and there were many manufacturing steps.

Although the work of arranging the key buttons at the time of assembling the front panel can be omitted, in order to bond the key buttons to a desired position on the elastomer resin sheet, a predetermined arrangement is made in the fixed die of the elastomer die. A step of arranging the key buttons was required for the insert part formed in (4). In the key button arrangement process, key button arrangement mistakes, front and back,
A defective product was generated due to an error in the vertical and horizontal directions.

Further, since the elastomer resin sheet is formed by compression molding, heating and pressing after mold closing and cooling after molding are required, and there is a problem that it takes time to take out the product from the mold.

Further, since the decorative portion is formed on the surface of the key button after molding, if the surface is a curved surface, it is difficult to decorate it by the printing means. Also, chemicolor treatment, laser marking treatment after painting, Since it is difficult to decorate complicated patterns and multi-colored patterns due to the plating process, etc., it has become a key button with little design effect.

In the keypad obtained by the conventional keypad manufacturing method, since the decorative portion is formed on the surface of the key button, the decorative portion is worn and the base is exposed by the contact when the key button is pressed. There was a problem to do.

Therefore, the present invention eliminates the above drawbacks and provides a keypad manufacturing method capable of efficiently manufacturing a keypad having a key button excellent in design effect and abrasion resistance with a small number of steps. The purpose is to do. Moreover, it aims at providing the keypad which has a key button excellent in a design effect and abrasion resistance.

[0010]

In order to achieve the above object, a method of manufacturing a key button according to the present invention comprises a pair of cavity molds for forming a plurality of independent cavities for molding a transparent resin layer. And a first core mold, a transfer material having a transfer layer for displaying a pattern formed on the base sheet is arranged so that the transfer layer faces the cavity mold side,
The mold is closed, and the resin is sent from the resin injection path provided on the cavity side to the resin gate provided at a part of the position corresponding to the thin portion inside the cavity, the resin is injected into the cavity, and Forming a transparent resin layer consisting of a protruding button portion and a thin portion around the button portion and forming a transfer layer on the back surface of the transparent resin layer, opening the mold, peeling the base sheet from the transfer layer, and then The cavity mold holding the transparent resin layer and the second core mold are closed to form a cavity for molding the common elastomer resin layer on the back surface of each button portion and each thin portion, and the elastomer is formed in the cavity. The resin was injected, and finally the mold was opened to take out the keypad. In addition, a painting film is arranged between a pair of cavity molds forming a plurality of independent cavities for molding the transparent resin layer and the first core mold,
The mold is closed, and the resin is sent from the resin injection path provided on the cavity side to the resin gate provided at a part of the position corresponding to the thin portion inside the cavity, the resin is injected into the cavity, and A cavity that forms a transparent resin layer consisting of a protruding button part and a thin part around the button part, integrates a painting film on the back surface of the transparent resin layer, opens the mold, and then holds the transparent resin layer The mold and the second core mold are closed, a cavity for molding a common elastomer resin layer is formed on the back surface of each button portion and each thin portion, and the elastomer resin is injected into the cavity. Finally, The mold may be opened and the keypad may be taken out.

The keypad of the present invention is manufactured by any one of the above keypad manufacturing methods. A keypad manufactured by any one of the above keypad manufacturing methods, comprising a button portion protruding on the front surface and a thin portion around the button portion, and the back surface of the button portion and the back surface of the thin portion are surfaces. A plurality of key buttons having a transfer layer formed on the back surface of one transparent resin layer may be held by an elastomer resin layer formed on the back side. A keypad manufactured by any one of the above keypad manufacturing methods, comprising a button portion protruding on the front surface and a thin portion around the button portion, and the back surface of the button portion and the back surface of the thin portion are surfaces. On the back surface of the transparent resin layer, which is one, a plurality of key buttons, which are integrated with a painting film, may be held by an elastomer resin layer formed on the back side.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings. 1 and 2 are schematic cross-sectional views each showing one step of the method for manufacturing a keypad of the present invention. 3, 4, and 5 are schematic cross-sectional views showing an embodiment of the keypad of the present invention. FIG. 6 is a schematic sectional view showing an example of the transfer material. FIG. 7 and FIG. 8 are schematic cross-sectional views showing an example of the painted film. 9 and 10
11 and 11 are schematic cross-sectional views each showing one step of the method of manufacturing the keypad of the present invention. 12 and 13 are schematic cross-sectional views each showing one step of the method of manufacturing the keypad of the present invention using a painting film. 14 and 15 are perspective views respectively showing an embodiment of the key button of the present invention. 16 and 17 show
It is a schematic cross section which shows each one Example of the key button of this invention. FIG. 18 is a schematic cross-sectional view illustrating the side gate. FIG. 19 is a schematic sectional view showing an example of the resin gate. 20 and 21 are schematic sectional views showing an example of the cavity. FIG. 22 is a schematic sectional view illustrating a front panel using the keypad of the present invention. In the figure, 1 is a transparent resin layer, 2 is a button portion, 3 is a thin portion, 4 is an elastomer resin layer, 5 is a protruding portion, 10 is a transfer material, 11 is a base sheet, 12 is a transfer layer, 13 is a release layer, 14 is a design layer, 15 is an adhesive layer, 20 is a paint film, 21 is a cavity, 22 is a cavity type, 23 is a first core type, 24 is a cavity, 25 is a second core type, 26
Reference numerals 28 and 28 denote resin gates, and 27 and 29 denote resin injection paths.

The keypad of the present invention has a plurality of key buttons in which a transfer layer 12 is formed on the back surface of a transparent resin layer 1 composed of a button portion 2 protruding on the front surface and a thin portion 3 around the button portion. , The elastomer resin layer 4 formed on the back side
It was held by (see FIG. 3). The keypad of the present invention has a plurality of key buttons, which are integrated with a painting film, on the back side of the transparent resin layer 1 including the button portion 2 protruding on the front surface and the thin portion 3 around the button portion. Including those held by the formed elastomer resin layer 4 (see FIGS. 4 and 5). In the keypad of the present invention, by providing the booklet portion 2 around the button portion 3, the adhesive area between the elastomer resin layer and the key button is large, and the adhesive force between the two is large.

The elastomer resin layer 4 may have a shape having a protrusion 5 on the back side of the button portion 2 (see FIGS. 3, 4 and 5). Further, the button portion 2 protruding on the front surface and the back surface of the thin portion 3 around the button portion may be flush with each other. On the same plane, the back surface of the button portion 2 and the back surface of the thin portion 3 are flat (see FIG. 16), and the button portion 2
Both the state where the back surface of (1) and the back surface of the thin portion 3 are curved surfaces (see FIG. 17) are included.

The transparent resin layer 1 is transparent or semi-transparent so that the pattern such as letters, numbers and figures formed on the back surface can be identified through the button portion 2 when viewed from the front surface. The transparent resin layer 1 may be either colorless and transparent or colored and transparent.

As the material of the transparent resin layer 1, hard resins such as acrylonitrile styrene, acrylonitrile styrene butadiene, polystyrene, vinyl chloride, acrylic, polyacrylate, polycarbonate, polyester, polyurethane and polypropylene can be used. Alternatively, a soft resin such as a styrene-based, urethane-based, polyester-based, olefin-based, polyamide-based, vinyl chloride-based plastic elastomer or polymerization-curable silicone elastomer may be used. A hard resin is effective in that the button portion is not easily scratched. A soft resin is effective in that it has cushioning properties and soft touch.

In order to express pictures such as letters, numbers and figures on the keypad, when the transparent resin layer 1 is injection-molded, the transfer material 10 or the paint film 20 is provided between the cavity mold and the first core mold. By sandwiching and encapsulating, the decorative portion is formed on the back surface of the transparent resin layer 1 simultaneously with the molding of the transparent resin layer 1.

The transfer material 10 is one in which a transfer layer 12 for displaying a picture is formed on a base sheet 11 (FIG. 6).
reference).

As the material of the base sheet 11, a resin sheet of polypropylene resin, polyethylene resin, polyamide resin, polyester resin, acrylic resin, polyvinyl chloride resin, etc., metal foil such as aluminum foil, copper foil, etc. , Cellulose sheets such as glassine paper, coated paper, cellophane, etc., or composites of the above respective sheets, which are used as a base sheet of a normal transfer material can be used.

A transfer layer 12 for displaying a picture is formed on the base sheet 11. The transfer layer 12 has a function of displaying a pattern on the key button. The transfer layer 12 has a button portion 2 protruding on the surface after the simultaneous transfer of molding.
It is formed on the back surface of the transparent resin layer 1 including the thin portion 3 around the button portion, and the pattern can be confirmed through the button portion 2 when viewed from the front surface. Further, when the key button is a translucent button, the function of displaying the pattern can be more remarkably exhibited by applying light from the back side. The transfer layer 12 includes a pattern layer 14 for displaying a pattern, a release layer 13 for releasing the base sheet from the transfer layer, an adhesive layer 15 for adhering the transfer layer to the transparent resin layer, and the like.

When the transfer layer 12 can be easily peeled from the base sheet 11, the transfer layer 12 may be directly provided on the base sheet. In order to improve the releasability of the transfer layer 12 from the base sheet 11, a release layer may be entirely formed before providing the transfer layer 12 on the base sheet (not shown).
The release layer is formed on the base sheet 1 after the transfer or the simultaneous transfer of molding.
When 1 is peeled off, it is released from the transfer layer together with the base sheet 11. The material of the release layer, melamine resin-based release agent, silicone resin-based release agent, fluororesin-based release agent, cellulose derivative-based release agent, urea resin-based release agent, polyolefin resin-based release agent, A paraffin-based release agent and a composite release agent of these may be used. Examples of the method for forming the release layer include a coating method such as a roll coating method and a spray coating method, and a printing method such as a gravure printing method and a screen printing method.

The peeling layer 13 is for peeling the base sheet 11 or the base sheet 11 and the release layer from the transfer layer 12. The release layer 13 is wholly or partially formed on the base sheet 11 or the release layer. Examples of the material of the release layer 13 include acrylic resin, polyester resin, polyvinyl chloride resin, cellulose resin, rubber resin,
In addition to polyurethane-based resins and polyvinyl acetate-based resins, vinyl chloride-vinyl acetate copolymer-based resins, ethylene-vinyl acetate copolymer-based resins and other copolymers, UV curable resins and other photo-curable resins, electron beam curable resins A radiation curable resin such as a resin or a thermosetting resin may be selected and used. As a method for forming the release layer 13, there are a coating method such as a gravure coating method, a roll coating method, and a comma coating method, and a printing method such as a gravure printing method and a screen printing method. When the pattern layer 14 has releasability with respect to the base sheet 11 or the release layer, the release layer 13 is not necessarily required.

The picture layer 14 is a layer for displaying a picture. The pattern layer 14 is formed on the release layer 13. The pattern layer 14 is the base sheet 1 when the release layer 13 is not provided.
1 or formed on the release layer.

The pattern layer 14 may be composed of, for example, a base portion and a display portion. The display of the display portion includes characters, numbers, figures, and the like. A so-called translucent button can be obtained by making a part of the pattern layer 14 translucent.

The pattern layer 14 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,
A colored ink containing a resin such as an alkyd resin as a binder and a pigment or dye of an appropriate color as a colorant may be used. As a method for forming the print 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, offset printing and gravure printing are suitable for multicolor printing and gradation expression. Further, in the case of a single color, a coating method such as a gravure coating method, a roll coating method or a comma coating method can be adopted. The print layer may be provided entirely or partially depending on the design to be expressed.

The pattern layer 14 is composed of a metal thin film layer,
Alternatively, it may be a combination of a printed layer and a metal thin film layer. Since the metal thin film layer has a high concealing property, it is effective when used in a light-shielding portion of a translucent button. For example, when the pattern layer 14 is a combination of a base portion made of a metal thin film layer and a display portion made of a translucent print layer and light is applied from the back surface, the base portion hardly transmits light. The display part that passes through can be recognized more clearly. The metal thin film layer is formed by a vacuum vapor deposition method, a sputtering method, an ion plating method, a plating method or the like. In this case, aluminum, nickel, or
Metals such as gold, platinum, chromium, iron, copper, tin, indium, silver, titanium, lead and zinc, and alloys or compounds thereof are used. 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 formed on the entire surface, 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. Further, as another example, there is a method of forming a metal thin film on the entire surface, then forming a resist layer on the portion where the metal thin film is to be left, and etching with acid or alkali to remove the resist layer. . When providing the metal thin film layer, a front anchor layer or a rear anchor layer may be provided (not shown) in order to improve the adhesion between the other transfer layer and the metal thin film layer. As the material of the front anchor layer and the rear anchor layer, two-component curing urethane resin, thermosetting urethane resin, melamine resin,
Cellulose ester resin, chlorine-containing rubber resin, chlorine-containing vinyl resin, acrylic resin, epoxy resin,
It is preferable to use a vinyl-based copolymer resin or the like. As a method of forming the front anchor layer and the rear anchor layer, there are a coating method such as a gravure coating method, a roll coating method and a comma coating method, and a printing method such as a gravure coating method and a screen printing method.

The adhesive layer 15 is for adhering the above layers to the back surface of the transparent resin layer 1. The adhesive layer 15 is formed on a portion to be bonded. That is, when the portion to be adhered is entirely, the adhesive layer 15 is entirely formed on the pattern layer 14. Further, when the portion to be adhered is partial, the adhesive layer 15 is partially formed on the pattern layer 14. Adhesive layer 15
For this, a heat-sensitive or pressure-sensitive resin suitable for the material of the transparent resin layer 1 may be appropriately used. For example, when the material of the transparent resin layer 1 is acrylic resin, acrylic resin may be used. When the material of the transparent resin layer 1 is a polyphenylene oxide / polystyrene resin, a polycarbonate resin, a styrene copolymer resin, or a polystyrene blend resin, an acrylic resin, a polystyrene resin having an affinity with these resins, A polyamide resin or the like may be used. Further, when the material of the transparent resin layer 1 is polypropylene resin, chlorinated polyolefin resin, chlorinated ethylene-vinyl acetate copolymer resin, cyclized rubber and coumarone indene resin can be used. Adhesive layer 1
Examples of the forming method of 5 include a coating method such as a gravure coating method, a roll coating method, and a comma coating method, and a printing method such as a gravure printing method and a screen printing method. When the material for the pattern layer 14 has excellent adhesiveness to the transparent resin layer 1, the adhesive layer 15 can be omitted.

The paint film 20 is formed by forming a picture layer 14 for displaying a picture, an adhesive layer 15 for adhering the picture film 20 on the transparent resin layer 1 and the like on the base sheet 11 (FIG. 7, FIG. 7). (See FIG. 8). Painting film 20
Since the pattern layer is integrated with the base sheet on the back surface of the transparent resin layer, the base sheet and the pattern layer do not require releasability. The base sheet 11 and the adhesive layer 15 can have the same structure as the transfer material. The pattern layer 14 can be selected from the constitutions listed as the pattern layer of the transfer material. That is, the pattern layer 14 has adhesiveness to the base sheet 11,
After the insert molding, a material that does not peel from the base sheet 11 may be selected. When the adhesive layer 15 is provided,
It may be provided on the design layer 14 (see FIG. 7) or on the surface of the base sheet 11 opposite to the design layer 14 (see FIG. 8).

In the method of manufacturing the keypad of the present invention, 2
Use color molding method. That is, after the key button is obtained using the pair of cavity molds 22 forming the cavity 21 for molding the transparent resin layer 1 and the first core mold 23, the cavity mold 22 holding the transparent resin layer 1 and the The two-core type 25 is used to form the elastomer resin layer 4.

First, the steps required to obtain a key button will be described. There are two processes for obtaining the key button, namely, a case where the transfer material 10 is used for simultaneous molding transfer and a case where the decorative film 20 is used for insert molding.

A case of performing the simultaneous molding transfer method using the transfer material 10 will be described. First, a pair of cavity molds 2 for forming a cavity 21 for molding the transparent resin layer 1
2 and the first core mold 23, the transfer material 10 and the transfer layer 12
Are placed so that they face the mold side of the cavity 21, and the mold is closed (see FIG. 2). Next, resin is injected into the cavity from the resin gate 26 provided at a part of the cavity 21 at a position corresponding to the thin portion 3, and the button portion 2 protruding on the surface and the thin portion 3 around the button portion are formed. The transparent resin layer 1 made of is formed and the transfer layer 12 is adhered to the back surface of the transparent resin layer 1 (see FIG. 9). After cooling, the mold is opened and the base sheet 11 is peeled from the transfer layer 12 to obtain a key button (see FIG. 10).

A case where the insert molding method is carried out using the painted film 20 will be described. First, a painting film is placed between a pair of cavity molds forming a cavity for molding a transparent resin layer and a first core mold, and the molds are closed. When arranging the decorative film, in the case of the decorative film having an adhesive layer, the adhesive layer is arranged so as to face the cavity mold side. Further, in the case of a picture-bearing film having no adhesive layer, it is arranged so that the picture layer faces the cavity mold side (not shown). Next, a resin is injected into the cavity from a resin gate provided at a part of the cavity corresponding to the thin portion, and a transparent resin layer including a button portion protruding on the surface and a thin portion around the button portion is formed. And a decorative film is integrated with the back surface of the transparent resin layer (not shown). After cooling, the mold is opened and the key button is obtained. When a plurality of key buttons are formed by a single insert molding, the picture film integrated on the back surface of the transparent resin layer is cut off along the back surface shape of the transparent resin layer 1 as shown in FIG. However, it is usually used as it is in the next step without being cut off as shown in FIG.

Hereinafter, the cavity 21, the cavity mold 22, and the first mold used in the simultaneous molding transfer method and the insert molding method.
Details of the core mold 23 and the like will be described.

The cavity 21 is a space for forming the transparent resin layer 1 and has a shape composed of a button portion 2 protruding on the surface and a thin portion 3 around the button portion. The cavity 21 includes a pair of cavity mold 22 and the first core mold 2.
3 is a space formed when the mold is closed, and the cavity mold 22 side is concave as shown in FIG. 2 and the first core mold 23 side is flat, or the cavity mold 22 and the first core mold 23 are flat as shown in FIG. When both of the core molds 23 have a concave shape,
As shown in FIG. 20, the cavity mold 22 has a concave shape.
There is a case where the core die 23 side has a protruding shape.

The depth of the cavity 21 corresponding to the button portion 2 is 0.8 to 5.0 mm, and the cavity 21 corresponding to the thin portion 3
The depth of should be 0.3-2.0mm. The thickness of the button part 2
If it is thinner than 0.8 mm, the thickness of the button part 2 will be thinner than the plastic panel overlaid on the surface of the keypad, and there will be a problem that the button part will not come out from the window part. If the thickness of the button part 2 is thicker than 5.0 mm, it will be thicker. Button part 2 for meat molding
Since there is a problem of sink marks on the surface, the above range is preferred. If the thickness of the thin portion 3 is less than 0.3 mm, there is a molding problem such as poor resin flow from the thin portion 3 to the button portion 2. If the thickness of the thin portion 3 is more than 2.0 mm, the product The above range is preferable because there is a problem that the thickness of the front panel becomes too thick when incorporated into the front panel. The button portion 2 may have a circular shape, an elliptical shape, a rectangular shape, or any other shape as viewed from the surface. Book meat department 3
Is 0.5 to the outside of the button part 2 along the periphery of the button part 2.
It is preferable to have a shape protruding by 3.0 mm. If the protruding portion is less than 0.5 mm, there will be no space to install a resin gate, and if it is more than 3.0 mm, it is necessary to increase the distance between adjacent buttons, so when installing multiple key buttons on the front panel. Causes design problems. The book meat portion 3 may be the entire periphery of the button portion 2 as shown in FIG. 15, or may be a part of the periphery of the button portion 2 as shown in FIG. At a part of the position corresponding to the thin portion 3 in the cavity 21,
A resin gate 26 for injecting resin is provided in the cavity (see FIG. 2). In the keypad manufacturing method of the present invention, since the resin gate 26 is provided at a portion of the cavity 21 at a position corresponding to the thin portion 3, it is possible to prevent a gate mark from being left on the surface of the button portion 2.

The cavity mold 22 is provided with a recess for forming a cavity 21 in a pair with the core mold when the mold is closed, and a resin injection passage 27 for feeding the resin to the resin gate 26. In the plurality of independent cavities 21,
One resin injection passage 27 is provided for each (see FIG. 2). The resin gate is preferably a pin gate (see FIG. 2). For example, if the resin gate is a side gate (see FIG. 18), the transparent resin solidified in the resin gate before the elastomer resin layer common to the back surface of the button portion and each thin portion is formed on the back surface of the transparent resin layer 1. This is because the number of steps for separating the transparent resin layer 1 from the transparent resin layer 1 increases. Further, a resin injection passage 28 for sending out an elastomer resin in a later step may be provided in the cavity mold 22 (see FIG. 2).

Next, the step of forming the elastomer resin layer 4 will be described. After obtaining the key button in the above process, the cavity mold holding the transparent resin layer and the second core mold 2
5 and 5 are closed, and a cavity 24 for molding the common elastomer resin layer 4 is formed on the back surface of each button portion and each thin portion (see FIG. 11). Next, the elastomer resin is injected into the cavity 24 (see FIG. 1). After cooling, the mold is opened and the keypad is taken out.

The cavity 24 is a space for molding the common elastomer resin layer on the back surface of each button portion and each thin portion. The cavity 24 may be a space for molding the elastomer resin layer having the protrusion 5 on the back surface side of the button portion 2 (see FIG. 11). The cavity 24 is
Cavity mold 22 and second core mold 2 holding a transparent resin layer
5 is a space formed when the mold is closed and the transparent resin layer 1
Is a space formed between the transfer layer surface and the cavity mold surface and the second core mold surface (see FIG. 11). Further, it is a space formed between the painted film surface of the transparent resin layer 1 and the cavity mold surface and the second core mold surface (see FIG. 12). In addition, it is a space portion formed between the picture-bearing film surface of the transparent resin layer 1 and the second core mold surface (see FIG. 13).

A resin gate 28 is provided in the cavity 24. Further, the resin injection passage 29 for feeding the elastomer resin to the resin gate 28 may be formed on the cavity die 22 side (see FIG. 8) or on the second core die 25 side (not shown). No). The resin gate may be either a pin gate (see FIG. 11) or a side gate (see FIG. 19). Only one resin gate 28 or a plurality of resin gates 28 may be provided in the cavity 24.

As the elastomer resin layer 4, a styrene-based, urethane-based, polyester-based, olefin-based, polyamide-based or vinyl chloride-based thermoplastic elastomer resin or a polymerization-curable silicone elastomer resin can be used. Since the thermoplastic elastomer resin is used by being melted in advance, it is not necessary to apply heat and pressure after closing the mold. Therefore, as compared with the conventional compression molding which requires heating and pressurization, the time required to take out the product from the mold can be significantly reduced. When the key button is a translucent button, the elastomer resin layer 4 is transparent or translucent.

When the keypad of the present invention is incorporated into a surface panel of an audio device, a mobile phone, a home electric appliance, an automobile, etc., a plastic panel having a window corresponding to the button portion 2 is used (see FIG. 22). The button portion 2 of the keypad projects from the window portion of the plastic panel, and the thin portion 3 around the button portion is covered with the plastic panel. Therefore, the thin portion 3 is the button portion 2.
Exerts a function as a stopper that prevents the from protruding too much from the window.

[0042]

EXAMPLE A polyester resin film is used as the base sheet. On the base sheet, there is a release layer made of acrylic resin, and on the release layer, the letter part using vinyl chloride / urethane resin as binder and ink containing pigment and vinyl chloride / urethane resin as binder and dye. The pattern layer consisting of the base part using the contained ink,
An adhesive layer made of an acrylic resin was sequentially printed on the pattern layer by a gravure printing method to obtain a transfer material.

First, a pair of cavity mold and core mold for forming a cavity for molding the transparent resin layer were prepared. The depth of the cavity corresponding to the button portion was 2.5 mm, and the depth of the cavity corresponding to the thin portion was 1.0 mm. The resin injection path was provided on the cavity side, and the resin gate was a pin gate.

The transfer material was placed between the cavity mold and the core mold so that the transfer layer faced the cavity mold side, and the mold was closed. Next, inject the resin into the cavity from the resin gate provided at a position that communicates with a part of the thin portion in the cavity,
A transparent resin layer including a button portion protruding on the surface and a thin portion around the button portion was formed, and a transfer layer was formed on the back surface of the transparent resin layer. After cooling, the mold was opened and the base sheet was peeled from the transfer layer. The molding conditions are resin temperature 240
The mold temperature was 50 ° C. A transparent and colorless acrylic resin was used for the transparent resin layer.

Next, the cavity mold holding the transparent resin layer and the second core mold are closed to form a cavity for forming a common elastomer resin layer on the back surface of each button portion and each thin portion. Then, the elastomer resin was injected into the cavity, the mold was finally opened, and the keypad was taken out. The molding conditions are: resin temperature 210 ° C, mold temperature 4
The temperature was 0 ° C. A colorless and transparent polyester elastomer resin was used for the elastomer resin layer.

In this way, the transfer layer is formed on the back surface of the transparent resin layer which is composed of the button portion protruding on the front surface and the thin portion around the button portion, and the back surface of the button portion and the back surface of the thin portion are flush with each other. A keypad was obtained in which a plurality of key buttons formed by the above were held by the elastomer resin layer formed on the back side.

On the keypad obtained in the example, a plastic panel having a window corresponding to the button was placed. When shining light from the back side of the keypad and looking from the front side, there is no gate mark on the button part, and the pattern formed on the back side can be seen through the transparent resin layer, which has an excellent display function and excellent design effect and abrasion resistance. It became wear-resistant.

[0048]

According to the method of manufacturing the keypad of the present invention,
Since the step of forming the key button and the step of forming the decorative portion on the back surface of the key button are performed simultaneously, and the step and the step of forming the elastomer resin layer on the back surface of the key button are performed continuously, the steps are Less and more efficient.

According to the method of manufacturing a keypad of the present invention, a transfer material or a paint film is arranged between a pair of cavity molds forming a plurality of independent cavities for molding a transparent resin layer and a first core mold. Then, the mold is closed and resin is injected into the cavity to form a transparent resin layer, and a transfer layer is formed on the back surface of the transparent resin layer or a picture film is integrated, and then the cavity holding the transparent resin layer is formed. The mold and the second core mold are closed to form a cavity for molding a common elastomer resin layer on the back surface of each button portion and each thin portion, and the elastomer resin is injected into the cavity to form the keypad. As a result, the step of arranging the key buttons at the desired positions is not necessary in order to bond the key buttons at the desired positions on the elastomer resin sheet. Therefore, misalignment of key buttons, front and back, top and bottom,
It is possible to significantly reduce the occurrence of defective products due to mistakes in the left and right directions.

At the same time as the injection molding of the transparent resin layer, a decorative portion is formed on the back surface of the transparent resin layer by a transfer material or a painting film. Even if the surface is a curved surface, complicated patterns and multicolors can be applied. Since it is possible to decorate the pattern, it is possible to obtain a key button that exhibits an excellent design effect.

In the keypad of the present invention, since the decorative portion is formed on the back surface of the key button, the decorative portion will not be worn by the contact when the key button is pressed.

In the keypad of the present invention, the key button is composed of the button portion and the thin portion around the button portion, and the resin is injected into the cavity from the resin gate provided at a position communicating with a part of the thin portion. As it is manufactured, the surface,
It is a key button with an excellent design, with no gate marks on the back or sides.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing one step of a method of manufacturing a keypad of the present invention.

FIG. 2 is a schematic cross-sectional view showing a step in the method of manufacturing the keypad of the present invention.

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

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

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

FIG. 6 is a schematic cross-sectional view showing an example of a transfer material.

FIG. 7 is a schematic cross-sectional view showing an example of a painted film.

FIG. 8 is a schematic cross-sectional view showing an example of a painted film.

FIG. 9 is a schematic cross-sectional view showing a step of the method of manufacturing the keypad of the present invention.

FIG. 10 is a schematic cross-sectional view showing a step of the method of manufacturing the keypad of the present invention.

FIG. 11 is a schematic cross-sectional view showing a step in the method of manufacturing the keypad of the present invention.

FIG. 12 is a schematic cross-sectional view showing one step of the method for manufacturing a keypad of the present invention using a film with a paint.

FIG. 13 is a schematic cross-sectional view showing one step of a method for manufacturing a keypad of the present invention using a film with a paint.

FIG. 14 is a perspective view showing an embodiment of a key button of the present invention.

FIG. 15 is a perspective view showing an embodiment of the key button of the present invention.

FIG. 16 is a schematic cross-sectional view showing one embodiment of the key button of the present invention.

FIG. 17 is a schematic cross-sectional view showing an embodiment of the key button of the present invention.

FIG. 18 is a schematic cross-sectional view illustrating a side gate.

FIG. 19 is a schematic sectional view showing an example of a resin gate.

FIG. 20 is a schematic cross-sectional view showing an example of a cavity.

21 and 21 are schematic cross-sectional views showing an example of the cavity.

FIG. 22 is a schematic cross-sectional view illustrating a front panel using the keypad of the present invention.

FIG. 23 is a schematic cross-sectional view showing one step of a conventional keypad manufacturing method.

FIG. 24 is a schematic cross-sectional view showing one step of a conventional keypad manufacturing method.

FIG. 25 is a schematic sectional view showing an example of a conventional keypad.

[Explanation of symbols]

1 Transparent resin layer 2 button part 3 Thin wall 4 Elastomer resin layer 5 Projection 10 Transfer material 11 Base sheet 12 Transfer layer 13 Release layer 14 picture layers 15 Adhesive layer 20 Painted film 21 cavity 22 cavity type 23 First core type 24 cavities 25 Second core type 26 resin gate 27 Resin injection path 28 Resin gate 29 Resin injection path

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI B29K 105: 32 B29K 105: 32 B29L 31:34 B29L 31:34

Claims (5)

(57) [Claims] 1. A transfer layer for displaying a pattern is formed on a base sheet between a pair of cavity molds forming a plurality of independent cavities for molding a transparent resin layer and a first core mold. The transfer material was placed so that the transfer layer faced the cavity mold side, the mold was closed, and the transfer material was provided at a part of the position corresponding to the thin portion in the cavity from the resin injection path provided on the cavity mold side. The resin is sent to the resin gate, and the resin is injected into the cavity to form a transparent resin layer consisting of a button portion protruding on the front surface and a thin portion around the button portion, and a transfer layer is formed on the back surface of the transparent resin layer. Then, the mold is opened, the base sheet is peeled off from the transfer layer, and then the cavity mold holding the transparent resin layer and the second core mold are closed, common to the back surface of each button portion and each thin portion. Molding elastomer resin layer A method for manufacturing a keypad, characterized in that a cavity for forming is formed, an elastomer resin is injected into the cavity, the mold is finally opened, and the keypad is taken out. 2. A painting film is disposed between a pair of cavity molds forming a plurality of independent cavities for molding a transparent resin layer and a first core mold, and the molds are closed to the cavity mold side. From the resin injection path provided, the resin is sent to the resin gate provided at a part of the position corresponding to the thin part in the cavity, the resin is injected into the cavity, and the button part protruding around the surface and the periphery of the button part And forming a transparent resin layer consisting of a thin part of the transparent resin layer on the back surface of the transparent resin layer, opening the mold, and then molding the cavity mold and the second core mold holding the transparent resin layer. Close to form a cavity for molding the common elastomer resin layer on the back surface of each button part and each thin part, inject the elastomer resin into the cavity, and finally open the mold and open the keypad. A method of manufacturing a keypad, characterized by taking out the keypad. 3. A keypad manufactured by the method for manufacturing a keypad according to claim 1. 4. A keypad manufactured by the method for manufacturing a keypad according to claim 1, comprising a button portion protruding on the front surface and a thin portion around the button portion, and the back surface of the button portion and the thin portion. A keypad characterized in that a plurality of key buttons having a transfer layer formed on the back surface of a transparent resin layer that is flush with the back surface of the above are held by an elastomer resin layer formed on the back side. 5. A keypad manufactured by the method for manufacturing a keypad according to claim 2, comprising a button portion protruding on the front surface and a thin portion around the button portion, and the back surface of the button portion and the thin portion. A keypad comprising a transparent resin layer, which is flush with the back surface of the above, and a plurality of key buttons, which are integrated with a painted film, held by an elastomer resin layer formed on the back side of the transparent resin layer.