Patent Application
20050221058
The present invention relates to a key sheet member for facilitating the recognition of translucent pattern sections of characters, symbols and so on by illuminating them even in the nighttime or a dark room by irradiation from a back surface by means of a light source and a manufacturing method therefor and relates to a key sheet member including a multipoint input key of a portable telephone or the like and a manufacturing method therefor. The present invention can be applied to pushbutton switches and so on of home electric appliances, automobile components, business equipment and telecommunications equipment besides portable telephones.
In order to improve the visibility of characters and symbols when the pushbutton switches of portable telephones and the like are backlighted, there have been a demand for providing a key sheet member that expresses the characters and symbols by forming a light-shielding decoration layer partially into character patterns with a light-transmitting decoration layer served as a ground and a demand for providing a key sheet member that has luxurious feeling by making the light-transmitting decoration layer have a metallic luster with gloss somewhat suppressed.
As a method for obtaining a key sheet member of the aforementioned construction, there has been a method for plating the surface of a resin material molded by means of molding dies that have a cavity surface on which minute pits and projections are provided and subsequently bonding a plurality of button sections, which have been formed by overcoating a transparent resin by a spray coating method or the like, onto a plastic sheet.
Moreover, there have conventionally been adopted multicontact keys called the multi-function keys or multi-scroll keys capable of accepting multi-directional inputs in upward, downward, rightward, leftward and other directions in portable telephones and so on. Normally, these keys constitute a key sheet member 91 that has a center key capable of accepting a depthwise input independently at the center. For example, the multicontact key shown in
This conventional key sheet member, whose overcoat layer is formed of coating, has had an issue that the surface strength of the button sections has been insufficient and the metallic luster pattern of the portions frequently touched during long-term use has been impaired. There has been a further issue that control for obtaining the desired matted pattern or hairline pattern metallic luster has been difficult due to variation in the plating process.
Accordingly, the object of the present invention is to solve the aforementioned issues and provide a key sheet member that has excellent surface strength and a uniform metallic luster and a manufacturing method therefor.
In accomplishing the aforementioned object, the present invention is constructed as follows.
According to a first aspect of the present invention, there is provided a key sheet member which can be obtained by setting a decoration sheet in a prescribed position, preforming the sheet into a three dimensional configuration so that the sheet is protruded on a translucent substrate sheet side and a plurality of key button sections are formed, subsequently placing the sheet in molding dies and injecting a molten resin to integrate the transparent molten resin comprised of the plurality of key button sections with the decoration sheet,
However, with regard to the multicontact key, when the translucent substrate sheet is made of biaxially oriented polyethylene terephthalate or the like having no deep drawing characteristic, it is sometimes the case where the translucent substrate sheet is forcibly extended in the preforming stage and becomes thin to break or, if the thickness is increased so as to cause no break, it is sometimes the case where a long time is required until heating to an optimum preforming state, resulting in a degraded production efficiency.
Therefore, the following second aspect of the present invention is preferable when there is a multicontact key.
That is, according to the second aspect of the present invention, there is provided the key sheet member as defined in the first aspect, wherein the translucent substrate sheet is a resin film that has a thickness of 50 to 250 μm and is selected from a group consisting of polyamide, polyimide, olefin, urethane, polycarbonate/polybutylene terephthalate alloy resin, and polycarbonate/polyethylene terephthalate alloy resin; and an extension rate of the decoration sheet preformed so that the key button sections are formed in a three dimensional configuration falls within a range of 200 to 300%.
However, if a key sheet member to be frequently used as in a portable telephone is formed by printing on a substrate sheet, there still occasionally occurs a trouble that the mechanical characteristics of the substrate sheet deteriorate due to repetitive bending actions and the effects of a printing solvent during long-term use and cracks are generated at the peripheries of the key button sections of the decoration sheet (see the reference numeral 99 in
In the above case, according to the third aspect of the present invention, there is provided the key sheet member as defined in the second aspect, wherein the key button sections are reinforced by being backed with a rubber elastic layer in a vicinity of peripheries thereof.
In concrete, according to the fourth aspect of the present invention, there is provided the key sheet member as defined in the third aspect, wherein the rubber elastic layer is comprised of a mold resin layer and positioned so as to extend over outside portions of peripheries of the key button sections of the decoration sheet and a back surface of a molded piece for maintaining a configuration of the button.
Further, according to the fifth aspect of the present invention, there is provided the key sheet member as defined in the third aspect, wherein the rubber elastic layer is comprised of a printed layer and positioned so as to extend over outside portions of peripheries and inside portions of peripheries of the key button sections of the decoration sheet on a surface located on a patterned layer side of the substrate sheet.
According to the sixth aspect of the present invention, there is provided the key sheet member as defined in any one of the first through fifth aspects, wherein the translucent substrate sheet contains one to thirty percent by weight of a light diffusion material.
According to the seventh aspect of the present invention, there is provided the key sheet member as defined in the sixth aspect, wherein the translucent substrate sheet is laminated with a light diffusion layer that contains one to thirty percent by weight of a light diffusion material on an upper surface side of a transparent substrate sheet.
According to the eighth aspect of the present invention, there is provided the key sheet member as defined in any one of the first through fifth aspects, wherein the metal thin film layer has a visible light transmittance of one to thirty percent and is formed partially or overall.
According to the ninth aspect of the present invention, there is provided the key sheet member as defined in the seventh aspect, wherein the light diffusion layer is formed on the decoration sheet, and a visible light transmittance of three layers of the translucent substrate sheet, the metal thin film layer, and the light diffusion layer falls within a range of 10 to 30%.
According to the 10th aspect of the present invention, there is provided the key sheet member as defined in any one of the first through fifth aspects, wherein the translucent substrate sheet has a minute pits-and-projections portion on the surface thereof.
These and other aspects and features of the present invention will become clear from the following description taken in conjunction with the preferred embodiments thereof with reference to the accompanying drawings, in which:
Before the description of the present invention proceeds, it is to be noted that like parts are designated by like reference numerals throughout the accompanying drawings.
Embodiments of the present invention will be described in detail with reference to the drawings.
The key sheet member 1 according to the aforementioned construction is mounted so that each of the key button sections 19 is positioned on a metal dome 71 that is a movable contact arranged above a fixed contact of a push switch. If the key button section 19 is depressed by a finger, then the key button section 19 moves from an undepressed position (see the undepressed position II of
With regard to the key sheet member 1 of the first embodiment of the present invention, the decoration sheet 2 constructed by laminating at least the metal thin film layer 7 on the back surface side of the translucent substrate sheet 3, which has a visible light transmittance of 80 to 93% and a haze of 5 to 50%, is integrated with the plurality of transparent resin members 11 that constitute the plurality of key button sections 19 (see
The decoration sheet 2 is laminated with at least the metal thin film layer 7 via the anchor layer 6 on the back surface side of the translucent substrate sheet 3, which has a visible light transmittance of 80 to 93% and a haze of 5 to 50% (see
In the key sheet member 1 according to the first embodiment of the present invention, it is important that the translucent substrate sheet 3 has a visible light transmittance of 80 to 93% and a haze of 5 to 50%. As a material of the above-mentioned kind, there is a film fabricated by mixing and kneading a light diffusion material in, for example, the resin of the substrate sheet 3. If the visible light transmittance is within the range of 80 to 93%, an excellent metallic luster of a matted pattern, a hairline pattern or the like can be expressed. If the visible light transmittance falls short of 80%, no metallic luster is reproduced by the metal thin film layer 7. If the visible light transmittance exceeds 93%, minute scratches received on the substrate sheet 3 when the sheet is brought in contact with something tends to be conspicuous. If the haze is within the range of 5 to 50%, an excellent metallic luster of a matted pattern, a hairline pattern, or the like can be expressed. If the haze falls short of 5%, no metallic luster is reproduced by the metal thin film layer 7. If the haze exceeds 50%, light is excessively dispersed during backlighting, and the appearance becomes totally dark.
As the resin of the substrate sheet 3, there can be used a single layer or a laminate of two or more layers of a polyethylene terephthalate based resin, a polycarbonate based resin, an acrylic based resin, an olefin based resin, an urethane based resin, and a polycarbonate/polybutylene terephthalate alloy resin. However, if there is a multicontact key, it is preferable to use a film of a resin selected from the group consisting of polyamide, polyimide, olefin, urethane, a polycarbonate/polybutylene terephthalate alloy resin, and a polycarbonate/polyethylene terephthalate alloy resin.
As the light diffusing material contained in the substrate sheet 3, there can be used minute particles of titanium oxide, aluminum hydroxide, barium sulfate, a polystyrene based resin, and a styrene-methyl methacrylate copolymer based resin; an extender of silica or alumina; resin beads; or the like. The light diffusion material content is preferably one to thirty percent by weight. If the light diffusion material content in the resin of the substrate sheet 3 is within the range of one to thirty percent by weight, an excellent metallic luster of a matted pattern, a hairline pattern, or the like can be expressed. If the light diffusion material content falls short of one percent by weight, the metallic luster feeling is excessively enhanced as a consequence of the shortage of matted feeling and the like. Accordingly, there is concern about the impairment of visibility when a pattern of a character or the like is additionally expressed. If the light diffusion material content exceeds thirty percent by weight, there is concern about no reproduction of metallic luster by the metal thin film layer 7.
Moreover, a sheet with a minute pits-and-projections portion on the sheet surface provided by being put through a space between metal rollers on which the desired minute pits-and-projections configuration is formed during the film fabrication of the substrate sheet 3 can be used as the translucent substrate sheet 3. In this case, the desired minute pits-and-projections portion is the portion that has pits and projections to the extent that the same effects as those in the case where a light diffusion material is included can be obtained, or in concrete, the portion that has a mean surface roughness Ra of 5 to 100 μm. Moreover, the translucent substrate sheet 3 is not limited to the one constructed of a single layer as shown in
As the transparent substrate sheet 4, a resin sheet similar to the resin sheet of the translucent substrate sheet 3 can be used. As the resin of the light diffusion layer 5, there can be used an ionizing radiation curing resin, a thermoplastic resin, a thermosetting resin, or the like. As the light diffusion material contained in the resin of the light diffusion layer 5, a material similar to the light diffusion material used in the translucent substrate sheet 3 can be used.
The translucent substrate sheets 3 of FIGS. 2 and 3 preferably have a thickness of about 15 to 250 μm. If the thickness of the translucent substrate sheet 3 falls short of 15 μm, the film fabrication process of the translucent substrate sheet 3 becomes difficult and poor at handling in each process. Moreover, the translucent substrate sheet 3 cannot follow the extension thereof in the preforming stage and highly possibly break in a portion of a small thickness. If the thickness of the translucent substrate sheet 3 exceeds 250 μm, a long time will be required until the decoration sheet 2 is heated to an optimum preforming state, leading to a poor production efficiency. Even if the role of the key sheet member 1 as a surface protection layer is taken into consideration, a thickness greater than the above value is unnecessary and leads to a cost increase.
However, when a multicontact key as shown in
The evaluation methods of click feeling, key stroke property, and restoration property are as follows. It is to be noted that the key sheet member 110 for evaluation is formed as follows. That is, by sucking the decoration sheet 2 that employs the aforementioned substrate sheet 3 of the optimum construction of
<Evaluation of Click Feeling>
The key sheet member 110 for evaluation was set so as to be placed between an upper section 112A and a lower section 112B of a jig 112 for evaluation (see
<Evaluation of Key Stroke Property>
The key sheet member 110 for evaluation was set on the jig 112 for evaluation having the metal dome 113 so that the center key 54 of the display section 110 was positioned above the metal dome 113, and thereafter, a key stroke test was conducted on the center key 54 with a cylindrical key stroke jig 114 having a diameter φ of 10 mm with a load of 400 g/cm2 and a depression stroke of 0.4 mm at a rate of two times per second. The key stroke property was determined according to whether or not the connection section 59 located at the periphery of the center key 54 broke before the number of strokes exceeds the standard frequency of 50000 times.
<Evaluation of Restoration Property>
After surviving the aforementioned key stroke test, the restoration property was determined according to whether or not the center key 54 was restored into the original position.
The evaluation results are shown in Table 1 below.
As understood from the evaluation results, with the decoration sheet 2 employing the translucent substrate sheet 3 of the optimum construction shown in
Moreover, with regard to the key sheet member 1 of the first embodiment of the present invention, the key sheet member 1 to be frequently used may be reinforced by backing the substrate sheet 3 with the rubber elastic layer 21 or 29 in the vicinity of the peripheries of the key button sections 19 as shown in
In order to form the key sheet member 1 of the first mode by utilizing the decoration sheet 2 of the aforementioned construction, it is proper to do as follows as shown in
First of all, as shown in
Next, the decoration sheet 2 three-dimensionally molded is placed between metal dies 32 and 33 for injection molding of the molded pieces 23 for maintaining the button configuration. In the above case, it is acceptable to feed separated decoration sheets 2 one by one in sheet form or intermittently feed the necessary portions of an elongated decoration sheet 2.
Next, as shown in
Next, the metal dies 32 and 33 are opened so as to leave the decoration sheet 2 integrated with the button configuration maintaining molded pieces 23 inside the metal die 32. When the metal dies 32 and 33 are opened, either one movable side metal die among the metal dies 32 and 33 is moved in a direction in which the die moves apart from the fixed metal die located on the other side to open both the metal dies 32 and 33. After the metal dies 32 and 33 are opened, the metal die 33 that has the gate portions 33a is replaced by a different metal die 39 that has gate portions 39a. As shown in
In the process of molding the rubber elastic layer 21, the metal die 33 that has the gate portions 33a used in the process of molding the button configuration maintaining molded pieces 23 is merely replaced by the different metal die 39 that has the gate portions 39a. However, it is also acceptable to once take the decoration sheet 2 integrated with the button configuration maintaining molded pieces 23 out of the pair of the metal dies 32 and 33 after the molding of the button configuration maintaining molded pieces 23 and subsequently place the sheet between a different pair of metal dies for the molding of the rubber elastic layer 21.
Moreover, in order to obtain the key sheet member 1 of the second mode, it is proper to do as follows as shown in
First of all, as a decoration sheet 2, there is fabricated one in which the rubber elastic layer 29 is provided in the position where the layer extends over the outside portions of the peripheries and the inside portions of the peripheries of the recess portions 36 on the surface located on the patterned layer (e.g., any one of the metal thin film layer 7, the light-shielding colored layer 9, and the bonding layer 10) side of the substrate sheet 3 in addition to the aforementioned construction. This rubber elastic layer 29 may be provided between the substrate sheet 3 and a printed layer or a coated layer formed on the sheet or provided between any ones of the layers. As shown in
Subsequently, similarly to the first mode, three-dimensional forming is carried out by means of the three-dimensional forming die 26 so as to form the key button sections 19 protruding in prescribed positions on the substrate sheet 3 side located on the upper surface side as shown in
Next, similarly to the first mode, the decoration sheet 2, which has been three-dimensionally molded, is placed between metal dies 40 and 41 for injection molding of the button configuration maintaining molded pieces 23.
Next, similarly to the first mode, the metal dies 40 and 41 are closed as shown in
Moreover, in either the first mode or the second mode, the key sheet member 1 is obtained, and this is thereafter taken out of the metal dies. However, it is possible to trim the decoration sheet 2 of the key sheet member 1 as needed after taking the key sheet member out of the metal dies. If the decoration sheet 2 is punched into the desired configuration before the decoration sheet 2 is placed in the metal dies, there is no need to trim the decoration sheet 2. Moreover, the aforementioned metal dies for injection molding can be applied to either a vertical injection molding press or a horizontal injection molding press.
In the key sheet member 1 of the first embodiment of the present invention, as described above, the substrate sheet 3 is reinforced by being backed with the rubber elastic layer 21 or 29 in the vicinity of the peripheries of the key button sections 19 as shown in
The metal thin film layer 7 is a layer for expressing a metallic luster color. According to the metallic luster color desired to be expressed, it is proper to form the metal thin film layer 7 by a vacuum deposition method, a sputtering method, an ion plating method, a plating method, or the like while using a metal of aluminum, nickel, gold, platinum, chromium, iron, copper, tin, indium, silver, titanium, lead, zinc, or the like; or an alloy or a compound of these materials.
The metal thin film layer 7 is preferably formed with a thickness such that the visible light transmittance falls within a range of 1 to 30%. This is because the optical transparency at the time of backlighting is hindered if the visible light transmittance of the metal thin film layer 7 falls short of one percent and the metallic luster feeling is impaired if the visible light transmittance of the metal thin film layer 7 exceeds thirty percent. It is to be noted that the visible light transmittance of the metal thin film layer 7 of the present invention means the visible light transmittance of the single body of the metal thin film layer 7 unless otherwise specified. Moreover, in terms of the manufacturing process, the metal thin film layer 7 is preferably formed with a film thickness of 10 to 40 nm. This is because film thickness control during the deposition process is difficult when the film thickness of the metal thin film layer 7 falls short of ten nanometers and there is concern about corrosion when the film thickness of the metal thin film layer 7 exceeds forty nanometers.
The metal thin film layer 7 is formed overall or partially. By partially forming the metal thin film layer 7, patterns of characters, symbols, and so on can be expressed when a light source is arranged on the back surface side of the key sheet member 1. As a method for partially forming the metal thin film layer 7, there is an etching method for partially forming a masking layer on the metal thin film layer 7 formed overall on the substrate sheet 3 by the screen printing method or the like, thereafter immersing the sheet in an acid or alkali aqueous solution and then removing the metal layer other than the laminated portion. Moreover, there is a laser marking method for forming the metal thin film layer 7 and a light-shielding layer overall on the substrate sheet 3 and thereafter removing the metal thin film layer 7 and the light-shielding layer to the desired pattern configuration by a laser beam. Moreover, it is acceptable to form the light-shielding colored layer 9 in order to give a certain light-shielding property to the metal thin film layer 7. The light-shielding colored layer 9 may be formed by concurrently using the layer as the masking layer when the metal thin film layer 7 is partially formed (see
Moreover, when there is required interlayer close adhesion reinforcement between the substrate sheet 3 and the metal thin film layer 7, it is acceptable to provide an anchor layer 6 (see
Moreover, it is acceptable to express characters, symbols, patterns, and so on by providing a patterned layer (e.g., any one of the metal thin film layer 7, the light-shielding colored layer 9, and the bonding layer 10). As a material for the patterned layer, it is proper to use a resin such as a polyvinyl based resin, a polyamide based resin, a polyester based resin, an acrylic based resin, a polyurethane based resin, a polyvinyl acetal based resin, a polyesterurethane based resin, a cellulose ester based resin, or an alkyd resin as a binder and use a coloring ink that contains a pigment or dye of the appropriate color as a coloring agent. As a method for forming the patterned layer, it is proper to use an ordinary printing method such as the offset printing method, the gravure printing method, or the screen printing method. It is proper to partially form the patterned layer according to the pattern desired to be expressed.
Moreover, when the metal thin film layer 7 is partially formed, it is proper to provide a light-transmitting colored layer 8 that has a visible light transmittance of 50 to 95% to be formed in the other portions (see
Moreover, the bonding layer 10 may be formed as needed (see
The decoration sheet 2 constructed as above becomes the key sheet member 1 by being integrated with the plurality of transparent resin members 11 that become the key button sections 19. In order to obtain the key sheet member 1, it is proper to arrange the decoration sheet 2 inside the metal dies 12 where the cavities are formed by one metal die 12 that has the recess portions 36 forming the key button sections 19 of the key sheet member 1 and the other metal die 12 that has the gates for forming the transparent resin members 11 positioned on the back surface of the key sheet member 1, and inject a molten resin into the metal dies 12, integrating the decoration sheet 2 with the molten resin.
First of all, as shown in
The metal dies 12 to be used are able to constitute cavities 12c of one metal die 12A that has recess portions 12a forming the key button sections 19 of the key sheet member 1 and the other metal die 12B that has gates 12b for forming the transparent resin members 11 positioned on the back surface of the key sheet member 1. In the above case, it is acceptable to provide a metal die embossing 13 on the surface of each recess portion 12a of the metal die 12A as needed.
The decoration sheet 2 is placed between the metal dies 12A and 12B by means of a decoration sheet feed unit or the like and then fixed by means of a clamp or the like. It is acceptable to soften by heating the decoration sheet 2 with a heat source and make the sheet closely adhere to the cavity surface by vacuum suction.
Next, as shown in
For the transparent resin members 11, it is preferable to use a polycarbonate resin that has excellent transparency, heat resistance, and impact resistance. Moreover, it is possible to employ a general resin such as acrylonitrile-butadiene-styrene copolymer resin, which can be used as the transparent resin members 11 of the key sheet member 1.
By solidifying the molten resin and thereafter opening the metal dies, the key sheet member 1 of
Moreover, insert molding can be carried out as follows. First of all, the decoration sheet 2 is fixed to a preforming die that has recess portions of a configuration identical to that of the key button sections by means of a clamp or the like, and the decoration sheet 2 is next softened by heating with a heat source and concurrently subjected to vacuum suction to make the sheet closely adhere to the surface of the preforming die. Next, the vacuum suction is released, and the decoration sheet 2 is taken out of the preforming die. As described above, the preformed decoration sheet 2 can be obtained. Next, the preformed decoration sheet 2 is arranged between the metal dies 12 and fixed by means of a clamp or the like. Next, the metal dies 12 are tightly closed, and the molten resin is injected to mold a mold resin. By solidifying the transparent resin members 11 and thereafter opening the dies, the key sheet member 1 in which the decoration sheet 2 is integrated with the transparent resin members 11 can be obtained.
A 130-μm thick polycarbonate/polybutylene terephthalate alloy film (Bayfol film produced by Bayer Ltd.), which had a visible light transmittance of 80% and a haze of 10% and on the surface of which minute pits and projections were formed, was served as a translucent substrate sheet, and an anchor layer made of acrylic polyol was formed on it. Next, aluminum was deposited overall to form a metal thin film layer. Next, a light-shielding colored layer was formed overall by the screen printing method using a black ink (SG410 produced by Seiko Advance Ltd.) made of a two-part curing type urethane based resin and dried with hot blast at a temperature of 80° C. for five minutes. Next, an adhesive layer made of a vinyl chloride-vinyl acetate copolymer based resin was formed overall by the screen printing method and dried at a temperature of 80° C. for two hours to obtain a decoration sheet.
The thus-obtained decoration sheet was preformed into a three dimensional configuration by a high-pressure molding method. Next, the sheet was placed in molding dies that have a cavity configuration corresponding to this three dimensional configuration, and a polycarbonate resin (Makrolon 2205 produced by Bayer Ltd.) was injected as a molten resin and solidified by cooling to obtain a key sheet member.
The surface of the thus-obtained key sheet member had a uniform matted tone metallic luster and excellent surface strength.
A 100-μm thick polyethylene terephthalate film, which had a visible light transmittance of 90% and a haze of 8% and was blended with twenty percent by weight of titanium oxide fine particles as a light diffusing material, was served as a translucent substrate sheet, and a two-part curing type urethane based resin was coated on the translucent substrate sheet to carry out an easy bonding process. Next, an anchor layer made of acrylic polyol was formed on it. Next, aluminum was deposited overall to form a metal thin film layer. Next, a light-shielding colored layer was partially formed by the screen printing method using a black ink (SG410 produced by Seiko Advance Ltd.) made of a two-part curing type urethane based resin and dried with hot blast at a temperature of 80° C. for five minutes. Next, the sheet and layers were immersed in an alkaline solution to remove the metal thin film layer in the portions that were not covered with the light-shielding colored layer to form a light-transmitting pattern. Next, a light-transmitting colored layer was formed with a two-part curing type urethane ink so as to cover the light-transmitting pattern. Next, an adhesive layer made of a vinyl chloride-vinyl acetate copolymer based resin was formed overall by the screen printing method and dried at a temperature of 80° C. for two hours to obtain a decoration sheet.
The thus-obtained decoration sheet was preformed into a three dimensional configuration by the high-pressure molding method. Next, the sheet was placed in molding dies that have a cavity configuration corresponding to this three dimensional configuration, and a polycarbonate resin (Makrolon 2205 produced by Bayer Ltd.) was injected as a molten resin and solidified by cooling to obtain a key sheet member.
The surface of the thus-obtained key sheet member had a uniform matted tone metallic luster and excellent surface strength.
The present invention constructed as above therefore has the effects as follows.
In the key sheet member of the present invention, the decoration sheet, in which at least the metal thin film layer is laminated on the back surface side of the translucent substrate sheet that has a visible light transmittance of 80 to 93% and a haze of 5 to 50%, is integrated with the plurality of transparent resin members that become the plurality of key button sections. This key sheet member therefore has excellent surface strength also capable of tolerating the long-term use thereof.
The key sheet member manufacturing method of the present invention includes arranging the decoration sheet, in which at least the metal thin film layer is laminated on the back surface side of the translucent substrate sheet that has a visible light transmittance of 80 to 93% and a haze of 5 to 50%, in the metal dies that constitute the cavities defined by one metal die that has the recess portions for forming the key button sections of the key sheet member and the other metal die that has the gates for forming the transparent resin member positioned on the back surface of the key sheet member, and injecting the molten resin into the metal dies, thereby integrating the decoration sheet with the molten resin. With this arrangement, there can easily be obtained a key sheet member that has a metallic luster of a uniform matted pattern, a hairline pattern, or the like and excellent surface strength also capable of tolerating the long-term use thereof.
By properly combining the arbitrary embodiments of the aforementioned various embodiments, the effects possessed by the embodiments can be produced.
Although the present invention has been fully described in connection with the preferred embodiments thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications are apparent to those skilled in the art. Such changes and modifications are to be understood as included within the scope of the present invention as defined by the appended claims unless they depart therefrom.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2001-400612 | Dec 2001 | JP | national |
| 2002-12643 | Jan 2002 | JP | national |
| 2002-47524 | Feb 2002 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP02/13751 | 12/27/2002 | WO | 6/24/2004 |
