JP2006294346A - Manufacturing method of keytop for push button switch, and keytop for push button switch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a keytop for a push button switch and the keytop for the push button switch capable of reducing environmental load and improving productivity. <P>SOLUTION: The keytop 1 for the push button switch comprises a core material 11 formed of transparent resin, a light shielding layer for shielding light irradiated from a lower part of the keytop 1, a base coat 13 formed in order to secure adhesiveness to the resin for forming the core material 11, a metal layer 14 formed by silver mirror reaction, a protection layer 15 formed for preventing discoloration by oxidization of silver, a top coat 16 for protecting a surface of the keytop 1, a coloring part 17 and a pattern part 16a formed on a part of an upper surface side of the core material 11. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a key top for a pushbutton switch used in an electronic device and a keytop for a pushbutton switch.

2. Description of the Related Art Conventionally, there are electronic devices such as mobile phones in which a metal layer is formed on the surface of an operation button (key top for a push button switch) or the like in order to increase the beauty of appearance. This metal layer is formed on the front and back surfaces of the resin that is the core of the key top for the pushbutton switch. Conventionally, plating, vapor deposition, or sputtering is employed as a method for forming a metal layer on the front and back surfaces of the resin. Patent Document 1 below discloses a key top for a pushbutton switch in which a metal layer is formed on the back surface of a resin by plating, vapor deposition, sputtering, or the like. Patent Document 2 listed below discloses a key top for a pushbutton switch in which a metal layer is formed on the surface of a resin by plating.
JP 2000-231849 A Japanese Patent Laid-Open No. 2002-241988

  By the way, when the metal layer is formed by plating, chrome plating is generally used. However, when plating with chrome plating, hexavalent chromium, which is a harmful substance, must be used, which has a large environmental impact. Moreover, when forming a metal layer by vapor deposition or sputtering, generally a metal layer must be formed in a vacuum chamber, and productivity is low.

  Accordingly, an object of the present invention is to provide a manufacturing method of a key top for a pushbutton switch and a keytop for the pushbutton switch that can reduce the environmental load and improve the productivity in order to solve the above-described problems. To do.

  The method for manufacturing a key top for a pushbutton switch according to the present invention includes a step of forming a resin core material and a step of forming a metal layer on the upper surface side or the lower surface side of the core material. It is formed by these.

  The key top for a pushbutton switch of the present invention is a keytop for a pushbutton switch having a resin core, and includes a metal layer on the upper surface side or the lower surface side of the core material, and the metal layer is formed by a silver mirror reaction. It is characterized by that.

  According to these inventions, since the metal layer can be formed by a silver mirror reaction, the key top can have a high-grade metallic luster. Moreover, since a metal layer is formed using a silver mirror reaction, it can reduce an environmental burden. Furthermore, by forming a metal layer using a silver mirror reaction, it is not necessary to form the metal layer in a vacuum chamber, so that it can be processed continuously with other processes, and productivity is improved. Can do.

  In the method for manufacturing a key top for a pushbutton switch according to the present invention, the silver mirror reaction is preferably caused by applying an aqueous ammoniacal silver nitrate solution and a reducing solution to the surface to be coated. Thereby, since the metal layer can be formed by spraying and applying the ammoniacal silver nitrate aqueous solution and the reducing solution on the surface to be coated, productivity can be further improved.

  The method for manufacturing a key top for a pushbutton switch according to the present invention further includes a step of forming a through-hole penetrating the metal layer, and the through-hole is formed to represent a pattern including letters, numbers, symbols, figures, and the like. It is preferred that In this way, a pattern including letters, numbers, symbols, figures, etc. can be made to have a transmittance different from that of the background, so that each can be illuminated with different brightness. Therefore, a key top having high pattern visibility can be formed.

  The method for manufacturing a key top for a pushbutton switch according to the present invention further includes a step of forming a light shielding layer on the lower surface side of the metal layer, and the through hole is preferably formed through the metal layer and the light shielding layer. . In this way, only the pattern including letters, numbers, symbols, figures, etc. can be illuminated, so that the visibility of the pattern can be further enhanced.

  The method for manufacturing a key top for a pushbutton switch according to the present invention further comprises a step of forming a colored portion on the upper surface side of the core material and on the lower surface side of the metal layer, and the through hole is formed on the upper surface side of the colored portion. It is preferred that In this way, patterns of different colors can be displayed on the surface of each key top.

  The method for manufacturing a key top for a pushbutton switch according to the present invention further comprises a step of forming a pattern portion on the upper surface side of the metal layer, and the pattern portion represents a pattern including letters, numbers, symbols, figures, etc. Preferably it is formed. In this way, a pattern including letters, numbers, symbols, figures, etc. can be illuminated with a transmittance different from that of the background, so that the visibility of the pattern can be improved.

  In the method for manufacturing a key top for a pushbutton switch of the present invention, it is preferable to further include a step of forming a protective layer on the surface of the metal layer opposite to the core material. In this way, discoloration of silver that is easily oxidized can be effectively prevented.

  According to the manufacturing method of the key top for the pushbutton switch and the keytop for the pushbutton switch according to the present invention, it is possible to reduce the environmental load and improve the productivity.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for manufacturing a key top for a pushbutton switch and an embodiment of the keytop for a pushbutton switch according to the present invention will be described below based on the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the same element and the overlapping description is abbreviate | omitted.

[First embodiment]
First, a key top for a pushbutton switch according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view of a key top for a push button switch, and FIG. 2 is a view of the operation unit of the mobile phone on which a plurality of key tops for push button switches are arranged as viewed from directly above. A key top 1 for a pushbutton switch shown in FIG. 1 includes a core material 11 that forms a main body of the key top, a light shielding layer 12, a base coat 13, and a metal layer that are formed so as to cover the upper surface and side surfaces of the core material 11. 14, a protective layer 15 and a top coat 16.

  The core material 11 is formed of a transparent resin. Here, in the case of forming a metal layer by plating in a conventional character illuminated key top, the core material must be molded as a two-color molded product of an opaque ABS resin and a transparent resin that can be plated. Therefore, an expensive molding die having a complicated structure is required. For this reason, when a design change including a change in character shape or the like occurs, the number of days and costs required for development increase, and it is difficult to respond in a short period of time. On the other hand, according to the present invention, since the core material 11 can be molded as a single-color molded product of transparent resin, it can be molded with an inexpensive molding die, and the design has been changed. Can respond flexibly in a short period of time.

  The light shielding layer 12 is provided to block light emitted from the lower part of the key top 1.

  The base coat 13 is a primer layer formed in order to ensure adhesion between the resin forming the core material 11 and the metal layer 14.

  The metal layer 14 is formed by depositing silver by a silver mirror reaction. By forming such a metal layer 14, the key top can have a high-grade metallic luster. A specific method for forming the metal layer 14 will be described. First, for example, an aqueous ammoniacal silver nitrate solution and a reducing solution are sprayed on the surface to be coated. Thereby, a silver mirror reaction occurs on the surface to be coated, and the reduced silver is deposited on the surface to be coated to form the metal layer 14. Examples of the reducing solution include formaldehyde, acetaldehyde, glucose, and the like.

Here, a general method for depositing silver by a silver mirror reaction will be described. First, when aqueous ammonia (2OH ⁻ ) is added to an aqueous silver nitrate solution (2Ag ⁺ ) placed in a test tube, brown silver oxide (Ag ₂ O) precipitates. Thereafter, ammonia water is continuously added until the silver oxide precipitate disappears. Thereby, an ammoniacal silver nitrate aqueous solution (2 [Ag (NH ₃ ) ₂ ] ⁺ + 2OH ⁻ ) is generated.

  Next, for example, a reducing solution such as formaldehyde, acetaldehyde or glucose is added to the aqueous ammoniacal silver nitrate solution. Thereby, silver is reduced and silver is deposited on the glass wall of the test tube.

  Thus, by depositing silver that forms the metal layer 14 using the silver mirror reaction, the metal layer 14 can be formed without using harmful substances. Therefore, the environmental load can be reduced.

  Conventionally, for example, when a metal layer is formed by vapor deposition, it has been necessary to deposit the metal in a vacuum chamber as described above. Therefore, the primer process performed before this vapor deposition process and the coating process such as the top coat performed after the vapor deposition process are separated from the vapor deposition process and are processed separately and independently. On the other hand, according to the present invention, since the metal layer 14 is formed by spraying the aqueous ammoniacal silver nitrate solution and the reducing solution, the metal layer 14 is processed continuously with the application process such as the primer process or the top coat. Can do. That is, each manufacturing process can be processed by a consistent flow operation. Thereby, productivity can be improved.

  The protective layer 15 is formed immediately after the metal layer 14 is formed in order to prevent discoloration due to oxidation of silver.

  The top coat 16 is formed at the end of the process of manufacturing the key top in order to protect the surface of the key top.

  Moreover, the coloring part 17 and the pattern part 16a are formed in a part of upper surface side of the core material 11 shown in FIG. The pattern portion 16 a is formed as a through-hole penetrating each layer (the light shielding layer 12, the base coat 13, the metal layer 14, and the protective layer 15) formed by being laminated on the upper surface side of the core material 11. Formed. The through-hole is filled with a top coat material when the top coat 16 is formed. As shown in FIG. 2, when the push button switch key top 1 is viewed from directly above, the pattern portion 16a is represented as a pattern including letters, numbers, symbols, figures, and the like. By forming such a pattern portion 16a, a pattern including letters, numbers, symbols, figures, and the like can be made to have a transmittance different from that of the background, so that each can be illuminated with different brightness. . Therefore, a key top having high pattern visibility can be formed.

  The pattern portion 16a is formed by cutting with a laser. By cutting both the light shielding layer 12 and the metal layer 14, when the key top is illuminated, only the pattern portion such as letters and symbols can be lit, thereby further improving the visibility of the pattern on the key top. Can do.

  The colored portion 17 is formed on the lower surface of the light shielding layer 12 and the pattern portion 16a. By forming the colored portion 17, it is possible to display different color patterns (characters, numbers, symbols, figures, etc.) on the surface of each key top.

  In addition, it is good also as forming the pattern part 16a by filling the through-hole after being cut with a laser with the ink which has permeability | transmittance. The ink to be filled may be colored ink or uncolored ink. However, by filling the colored ink, it is possible to display patterns of different colors on the surface of each key top without forming the colored portion 17.

  In addition, the light shielding layer 12 is not necessarily formed. However, by forming the light shielding layer 12, only the pattern including letters, numbers, symbols, figures, and the like can be illuminated, so the light shielding layer 12 is not formed. The visibility of the pattern can be improved as compared with the case. Further, the base coat 13 may be colored in a light shielding color without forming the light shielding layer 12.

  In addition, the colored portion 17 is not necessarily formed, but since the colored portion 17 can be colored for each pattern, it is possible to meet various design preferences of the user.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 3 is a cross-sectional view of the key top for a pushbutton switch in the second embodiment. The key top 2 for the pushbutton switch in the second embodiment is different from the keytop 1 for the pushbutton switch in the first embodiment. First, in the keytop 1 for the pushbutton switch in the first embodiment, the coloring portion 17 and the pattern portion. 16a is formed on a part of the upper surface side of the core material 11, whereas in the push button switch key top 2 in the second embodiment, instead of the colored portion 17 and the pattern portion 16a in the first embodiment. The provided pattern portion 18 is formed on a part of the upper surface side of the protective layer 15. Further, in the push button switch key top 1 in the first embodiment, the light shielding layer 12 is formed on the lower surface side of the metal layer 14, whereas in the push button switch key top 2 in the second embodiment, the light shielding layer 12 is formed. The difference is that 12 is not formed.

  As shown in FIG. 3, the pattern portion 18 is formed on a part of the upper surface side of the protective layer 15 formed on the upper surface of the metal layer 14. Similarly to the pattern portion 16a in the first embodiment, the pattern portion 18 is represented as a pattern including letters, numbers, symbols, figures, and the like when the key top 2 for pushbutton switch is viewed from directly above. Moreover, since the pattern part 18 is formed, for example with an ink, the effect similar to the effect at the time of forming the colored part 17 in 1st Embodiment can be show | played by using the colored ink.

  By forming such a pattern portion 18, a pattern including letters, numbers, symbols, figures, and the like can be made to have a transmittance different from that of the background, so that each can be illuminated with different brightness. . Therefore, the pattern part 18 with high visibility can be formed.

  In addition, although the light shielding layer 12 is not formed in the key top 2 for pushbutton switches in 2nd Embodiment, it is good also as providing a light shielding layer on the upper surface of the core material 11 similarly to 1st Embodiment, and a base coat. 13 may be colored in a shading color. In these cases, the reflected light from the metal layer 14 when the push button switch key top 2 is viewed from directly above can be enhanced, so that the metallic luster on the surface of the key top can be more emphasized. .

  The description of each component other than this is omitted because it is the same as the description of each component in the first embodiment.

[Third embodiment]
Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 4 is a cross-sectional view of a key top for a pushbutton switch in the third embodiment. The key top 3 for the pushbutton switch in the third embodiment is different from the keytop 1 for the pushbutton switch in the first embodiment in the keytop 1 for the pushbutton switch in the first embodiment that has a metal on the upper surface side of the core material 11. In contrast to the layer 14 and the like being laminated, the key top 3 for the pushbutton switch in the third embodiment is that the metal layer 14 and the like are laminated on the lower surface side of the core material 11. Moreover, it differs also in the point provided with the pattern part 18 instead of the coloring part 17 and the pattern part 16a in 1st Embodiment.

  The key top 3 for a pushbutton switch shown in FIG. 4 includes a core material 11, a base coat 13, a metal layer 14, a protective layer 15, a light shielding layer 12, and an undercoat 19 formed on the lower surface side of the core material 11. Have. The undercoat 19 is formed at the end of the process of manufacturing the key top in order to protect the back surface of the key top.

  A pattern portion 18 is formed on a part of the upper surface side of the undercoat 19 shown in FIG. The pattern portion 18 is formed as a through-hole penetrating each layer (the metal layer 14, the protective layer 15, and the light shielding layer 12) formed by being laminated on the upper surface side of the undercoat 19. The through hole is filled with permeable ink. The ink to be filled may be colored ink or uncolored ink. However, it is possible to display different patterns of different colors on the surface of each key top by filling with colored ink. The pattern portion 18 formed in this way is a pattern including letters, numbers, symbols, figures, and the like when the key top 3 for the pushbutton switch is viewed from directly above, like the pattern portion 16a in the first embodiment. expressed.

  The description of each component other than this is omitted because it is the same as the description of each component in the first embodiment.

It is sectional drawing of the keytop for pushbutton switches in 1st Embodiment. It is the figure which looked at the operation part of the mobile telephone by which the key top for several pushbutton switches is arrange | positioned from right above. It is sectional drawing of the keytop for pushbutton switches in 2nd Embodiment. It is sectional drawing of the keytop for pushbutton switches in 3rd Embodiment.

Explanation of symbols

1, 2, 3... Key top for pushbutton switch, 11... Core material, 12 .. light shielding layer, 13 .. base coat, 14 .. metal layer, 15. ..Top coat, 16a, 18 ... pattern portion, 17 ... colored portion, 19 ... undercoat.

Claims (8)

A step of molding a resin core;
Forming a metal layer on the upper surface side or the lower surface side of the core material,
The method for manufacturing a key top for a pushbutton switch, wherein the metal layer is formed by a silver mirror reaction.   2. The method for manufacturing a key top for a pushbutton switch according to claim 1, wherein the silver mirror reaction occurs by applying an aqueous ammoniacal silver nitrate solution and a reducing solution to the surface to be coated. Further comprising forming a through hole penetrating the metal layer,
2. The method for manufacturing a key top for a pushbutton switch according to claim 1, wherein the through hole is formed to represent a pattern including letters, numbers, symbols, figures, and the like. Further comprising a step of forming a light shielding layer on the lower surface side of the metal layer,
4. The method for manufacturing a key top for a pushbutton switch according to claim 3, wherein the through hole is formed through the metal layer and the light shielding layer. Further comprising a step of forming a colored portion on the upper surface side of the core material and on the lower surface side of the metal layer,
The method for manufacturing a key top for a pushbutton switch according to claim 4, wherein the through hole is formed on an upper surface side of the colored portion. Further comprising the step of forming a pattern on the upper surface side of the metal layer,
2. The method for manufacturing a key top for a pushbutton switch according to claim 1, wherein the pattern portion is formed to represent a pattern including letters, numbers, symbols, figures, and the like.   The method for manufacturing a key top for a pushbutton switch according to any one of claims 1 to 6, further comprising a step of forming a protective layer on a surface of the metal layer opposite to the core material. . A key top for a pushbutton switch having a resin core,
A metal layer is provided on the upper surface side or the lower surface side of the core material,
The key top for a pushbutton switch, wherein the metal layer is formed by a silver mirror reaction.

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