JPH1172576A - Method of manufacturing case member and electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a case member capable of displaying fine patterns and letters on the surface of the outer case of a time piece by properly using plural kinds of surface processings. SOLUTION: On the surface of island-like plating layer 22a and Au plating layer 21, honing process is applied to roughen the surface. After completing the honing process, the island-like plating layer 22a is removed with an etching liquid and the Au plating layer 21 is peeled off so as to expose the surface of the outer case 10. At this moment, the mirror surface at the location where the island-like plating layer covering the surface is maintained and the surface at the location, where no island-like plating layer 22a coveres but Au plating layer 21 coveres, is made rough.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an exterior member, an electronic device, and a timepiece, and more particularly to a technique suitable for forming an external pattern of an exterior case of a timepiece.

[0002]

2. Description of the Related Art Conventionally, various surface processing techniques such as mirror finishing, streaking, and honing have been used in order to obtain a desired appearance of an external case of a timepiece. in this case,
By combining the mirror finishing with the streaking and honing, variations in the appearance of the outer case can be increased.

[0003]

By combining various surface treatments as described above, it is possible to give the appearance of the outer case a high-grade appearance or emphasize the novelty. For example, the exterior surface of the exterior case is roughly divided and processed by different processing methods, such as leaving the window frame portion of the exterior case mirror-finished and processing other than the window frame portion by streaking or honing. . This is because it is difficult to attach a highly rigid mask or the like on the surface of the outer case with high precision when applying the streaking or honing processing after the entire outer surface of the outer case is mirror-finished. This is because there is a problem that fine patterns and characters cannot be represented on the surface of the outer case by the method (1).

Accordingly, the present invention has been made to solve the above problems, and an object of the present invention is to express fine patterns and characters on the surface of an exterior member such as an exterior case of a timepiece by using different types of surface processing. It is another object of the present invention to provide a method for manufacturing an exterior member that can perform the above-described steps.

[0005]

In order to solve the above-mentioned problems, the present invention takes a step of forming a thin metal layer on the surface of an exterior member and a step of forming a partly thick metal layer on the surface of the metal layer. Forming a metal mask, performing a particle spraying process for roughening the surface of the exterior member through the metal layer from above the metal layer and the metal mask, and removing the metal mask And a method of manufacturing an exterior member.

According to this means, a thin metal layer is formed and then a thick metal mask is formed, and a particle spraying process is performed, so that a region covered with only the thin metal layer is covered with the metal layer through the metal layer. The surface of the member is roughened, and the region where the metal mask is formed is not roughened, so that the original surface state is maintained. Therefore, on the surface of the exterior member, a portion in the original surface state corresponding to the formation region of the metal mask and a roughened portion can be identifiably represented.

When the metal mask is formed to be thick, the surface of the exterior member can be surely protected during the particle spraying process, and can be easily formed into a desired pattern that can represent a fine pattern, a symbol, or a character. be able to. Further, by performing the particle spraying treatment through the thin metal layer, damage to the surface of the exterior member can be suppressed, and the surface irregularities can be smoothed, so that the corrosion resistance of the surface can be improved. . In addition, the smoothness of the surface irregularities creates a high-quality appearance and improves the feel.

Here, the metal layer is preferably made of a soft or highly ductile metal or alloy such as Au or Ni.

According to this means, by forming the metal layer using a soft or highly ductile metal or alloy, the surface of the exterior member can be surely protected while securing the effect of protecting the surface of the exterior member during the particle spraying process. Can be roughened.

It is preferable that the method further includes a step of removing the metal layer after the step of performing the particle spraying process.

According to this means, by removing the metal layer after the particle spraying treatment and exposing the surface of the exterior member, the surface of the exterior member represents a pattern, a symbol, or a character due to a portion having only a different surface state. be able to.

Further, it is preferable to provide a surface metal layer to be left on the final surface of the exterior member under the metal mask.

According to this means, by leaving the surface metal layer, it is possible to configure a design having not only the surface state but also the material texture and the color tone in the peripheral rough surface. .

After the metal layer and the metal mask are removed as described above, it is preferable that the surface of the exterior member is subjected to a dry film forming process.

By performing the surface treatment by the dry film forming method, it is possible to increase the hardness of the surface and to change the texture and color tone without changing the surface condition of the exterior member.

According to the present invention, it is possible to obtain an electronic device having an exterior member formed by the manufacturing method described in each of the above means. Here, the electronic device refers to various devices having an electronic function part, and includes a portable clock such as a wristwatch and a pocket watch, and other various clocks. In the case of watches, not only electronic watches but also mechanical watches are included.

[0017]

Next, an embodiment according to the present invention will be described with reference to the accompanying drawings.

(First Embodiment) First, FIGS.
A first embodiment according to the present invention will be described with reference to FIG. In this embodiment, an exterior formed by a metal injection molding (metal injection molding, hereinafter simply referred to as “MIM”) method using a metal such as austenitic stainless steel such as SUS304, pure titanium, or a titanium alloy as a material. Case 10 is used. FIG. 1 is a plan view showing the appearance of an outer case formed by a manufacturing method of the present embodiment described later.

On the front side of the outer case 10, there is provided a window frame portion 11 which is formed in a band shape so as to protrude slightly around a display window 10a formed in a central portion. The surface of the window frame portion 11 includes a mirror surface portion 11a processed into a mirror surface representing numbers, characters, and the like for displaying time and the like, and a rough surface portion 11b around the mirror surface portion 11a.
Parts other than the window frame part 11 in the exterior case 10 are also formed with a rough surface similarly to the rough surface part 11b. For this reason, the outer surface of the outer case 10 has an almost satin-like rough surface. The light is scattered by the rough surface, and the outer case 10 shines.
1a is configured to appear floating.

A method of manufacturing the outer case 10 shown in FIG. 1 will be described as a first embodiment with reference to FIGS.

After the outer case 10 is formed by the MIM method, the outer surface thereof is mirror-finished in advance by buffing or the like. As shown in FIG. 2, on the surface 10b of the mirror-finished outer case 10, a thin film having a thickness of about 0.5 μm or less,
An Au plating layer 21 made of u or an Au alloy is entirely formed.

The thickness of the Au plating layer 21 can be appropriately set according to the mechanical properties of Au as a material of the plating layer and honing processing conditions described later.
The range of 0.05 to 0.6 μm is preferred. This range is
In the honing treatment within the normal condition range, if the value is less than the upper limit, the surface 10b of the outer case 10 can be sufficiently roughened in a state in which the surface 10b can be visually recognized as an external appearance. The reason for this is that it is possible to alleviate the damage to the surface and the sharpness of the surface irregularities, and to achieve a good satin finish for decoration. Especially within these ranges,
About 0.2 to 0.4 μm is most desirable in view of the strength and condition of the honing treatment.

Instead of the Au plating layer 21, layers made of various metals or alloys can be used. These layers are not limited to the above-mentioned electrolytic plating, but may be formed by electroless plating, ion plating, vapor deposition, sputtering, or the like. Can be formed by various methods. As a metal material,
A relatively soft and highly ductile material such as Au or Ni is preferred. However, when finally removing from the surface of the outer case 10, the outer case 1 like the Au plating layer 21 is used.
A material having a color tone different from 0 is preferable in that the presence or absence of the residue can be easily determined. Further, it is desirable that the material is unlikely to change with time such as corrosion and deterioration even if it remains on the surface of the outer case 10 like the Au plating layer 21.

Next, as shown in FIG.
Cu plating (electrolytic plating) on the surface of 1
To provide a Cu plating layer 22 made of Cu or a Cu alloy.
To form The thickness of the Cu plating layer 22 is about 5 to 10 μm
Degree. The Cu plating layer 22 serves as a metal mask at the time of honing processing to be described later.

This metal mask can be formed of various metals or alloys of various metals in terms of physical properties. As the metal material, a relatively soft (low hardness) metal or alloy such as Au, Ni, or Ag is preferable. The thickness of the metal mask varies depending on the material, but is 3
About 50 μm is preferable. This is because a thinner plate does not function as a mask, and a thicker one increases the manufacturing cost.

The method of forming this layer is not limited to electrolytic plating.
Various methods such as electroless plating, ion plating, vapor deposition, and sputtering can be employed. However, since it is necessary to form a relatively thick metal or alloy in this step, it is desirable to select a method in which the material is inexpensive and does not require a long time in order to reduce the manufacturing cost.

Next, as shown in FIG. 4, an etching mask 23 made of a synthetic resin such as a resist is formed. The etching mask 23 may be formed by a photolithography technique such as resist coating, exposure, and development. In the present embodiment, in order to reduce the manufacturing cost, the resist is selected by a method such as tachography or screen printing. Is applied. In this case, it is desirable to prevent mask defects such as generation of pinholes by applying and printing two or more times.

Next, as shown in FIG.
The whole is immersed in a predetermined etching solution, and the Cu plating layer 22 is etched to form an island-shaped plating layer 22 a having a pattern corresponding to the pattern of the etching mask 23. In the case of this embodiment, the etching solution is a mixed aqueous solution of a hydrogen peroxide solution and sulfuric acid, and the etching can be completed in about several minutes. Thereafter, an aqueous solution of a strong alkali such as sodium hydroxide is set at about 60 ° C. for about 10 minutes.
By immersing the outer case 10 in this aqueous solution, the etching mask 23 is removed as shown in FIG.

In this state, the island-shaped plating layer 22a and the Au
A honing process is performed on the surface of the plating layer 21, and FIG.
The surface is roughened as schematically shown in FIG. In this honing treatment, mesh No. 320 (about 5 to 50 μm
) Glass beads were sprayed at a pressure of about 1 to 3 kg / mm ^{2 for} about 10 to 20 seconds, so that the outer surface on the front side of the outer case 10 was almost uniformly roughened. For the honing treatment, inorganic particles such as ceramic particles other than glass beads and other various hard particles can be used, and it is also possible to carry out the treatment by so-called sandblasting or scrub polishing. The pressure of the particles to be sprayed is preferably adjusted as appropriate depending on the case material and the thickness of the Au plating layer 21, and the particle size of the particles to be sprayed is preferably appropriately used depending on the desired appearance and the case material.

Next, after the honing process is completed, the island-shaped plating layer 22a is removed as shown in FIG. 8 by using an etching solution similar to the etching solution used in the above-described etching process shown in FIG. By exfoliating the Au plating layer 21 with a reducing agent containing cyan or the like, the surface of the outer case 10 is exposed as shown in FIG. At this time, of the surface, at the place where the island-shaped plating layer 22a was covered, the surface is maintained as a mirror surface, the island-shaped plating layer 22a is not covered, and only the Au plating layer 21 is covered. The surface is rough in the place where it was.

Finally, if necessary, the outer surface of the outer case 10 is subjected to ion plating. This processing is performed when it is necessary to increase hardness or obtain a desired color tone in order to improve the scratch resistance and abrasion resistance of the outer surface of the outer case 10.

This ion plating process was performed as follows. First, the outer case 10 is placed in a chamber of an ion plating apparatus that has been evacuated, and argon gas is introduced into the apparatus so that the pressure falls within 2.5 to 10
And a negative voltage of 0.5 kV is applied to the outer case 10.
The degree was applied, and ion bombardment was performed for 5 minutes to clean the surface of the outer case 10.

Then, argon gas is discharged from the chamber, the pressure of the chamber is reduced to about 1 to 3 × 10 ⁻² Pa, and pure Ti or pure Cr is evaporated by electron beam heating to form a reactive gas. N ₂ Gas, C ₂ H ₂ gas, O
Introduce a certain amount of at least one of the _two gases,
Finally, at a pressure of about 5 to 10 × 10 ^-2 Pa, 0.1
A voltage of about kV is applied to the outer case 10 to generate plasma, and the Ti shown in FIG.
A film 11c of a compound or a Cr compound was formed to a thickness of about 1 μm.

The thickness of the coating 11c is pure Ti or pure C
It was controlled by adjusting the evaporation time of r. This is because the hardness is almost determined by the composition of the film and the film forming conditions, but the durability and color tone also vary depending on the thickness of the film. Usually, a thickness of about 0.5 to 2 μm is desirable. As shown in Table 1 below, various colors such as gold, gray, brown, metal (similar to stainless steel) and blue depending on the material of the evaporation source and the film forming conditions are shown in Table 1 below. It is possible to get. Note that the coating may be formed by stacking two or more layers under different conditions or different materials.

[0035]

[Table 1]

In the film forming method using the ion plating method as described above, Ti, Zr, Hf, V, Nb, Ta,
A compound of W or the like and at least one of C, N and O containing these as a main component, or Au, Pt, Pd and Ag
Various colored films can be obtained by using noble metals and alloys such as. In addition, as a method of forming a colored film, in addition to the ion plating method, a vacuum evaporation method,
Various dry film formation methods such as a sputtering method can be used. By using these dry film forming methods, surface hardening and color tone can be imparted without significantly impairing the discrimination and surface state between the roughened surface portion 11b that has been subjected to the honing treatment and the mirrored surface portion 11a that has been kept in a mirrored state by a mask. It can be performed.

The outer case used in the present embodiment is made of stainless steel, pure titanium, a titanium alloy or the like, but the outer case made of another metal material such as brass, nickel silver, etc. Can also be used.
In addition to the metal material, the present invention can be applied to an outer case formed of a synthetic resin. However, if there is a problem in the adhesion between these substrates and the above-mentioned various coatings, it is necessary to form the base layer on the surface of the substrate and then perform the above-described steps.

In this embodiment, in particular, during the honing process, the hard particles used for the honing process are directly covered by the roughening while the surface of the exterior member is covered with the thin Au plating layer 21. Since it does not hit the surface of the case 10, the formation of a damaged layer on the surface of the outer case 10 can be suppressed, and the unevenness of the surface of the outer case 10 becomes smooth, so that the corrosion resistance of the outer case 10 Can be suppressed. Also,
When the surface irregularities of the outer case 10 are smoothed, a high-quality appearance is obtained and the feel is also improved in terms of appearance.

(Second Embodiment) Next, FIGS.
A second embodiment of the method for manufacturing an exterior member according to the present invention will be described with reference to FIG. In this embodiment, instead of forming a metal mask directly on the surface of the outer case 10, a metal mask previously formed in a predetermined pattern shape is pasted on the surface of the outer case 10. It was done.

This metal mask is formed as follows through the same forming process as the ornament stuck on the dial of the timepiece. First, as shown in FIG. 11, a resist is applied to a predetermined metal substrate 30, exposed in a predetermined pattern, and then developed to form a predetermined mask pattern 31. Then, after protecting the back surface of the substrate 30, N
i-plating, finish plating, etc.
To form This plating mask 32 can be
It can be formed by various platings such as Au, Ag, and Cu. Usually, a thin Au plating for finishing is performed on the surface of the thick Ni plating.

The plating mask 32 formed on the substrate 30 is transferred to a synthetic resin transfer film 33 having an adhesive layer on one surface, and is separated from the substrate 30 and the mask pattern 31. Thereafter, an adhesive 34 (see FIG. 12) is applied to the back surface (peeling surface) of the plating mask 32, and the plating mask 32 is stored with a release paper (not shown) attached to the back surface side.

An Au plating layer 21 is formed on the surface of the outer case 10 as in the first embodiment. This A
The plating mask 32 transferred to the transfer film 33 described above is bonded and arranged on the surface of the u-plated layer 21 by the bonding layer 34. After that, after peeling the transfer film 33,
Honing is performed in the same manner as in the first embodiment, and FIG.
As shown in FIG. 3, the Au plating layer 21 and the plating mask 3
The surface of No. 2 is roughened. After the honing process is completed, the plating mask 32 is peeled off as shown in FIG. 14, and the remaining adhesive layer 34 is removed with a solvent or the like. Thereafter, the removal of the Au plating layer 21 and the ion plating process are performed as in the first embodiment.

In this embodiment, the plating mask 32 is formed on the substrate 30 in advance and is transferred to the outer surface of the outer case 10 for use. There is an advantage that formation is easy. In other words, when a photolithography process for forming the plating mask 32 is performed on the substrate 30 and the shape and arrangement of the plating mask 32 are formed with high precision in advance, the plating mask is formed on the outer case 10. In comparison with this, construction, maintenance, and management of production facilities are easier, and production can be performed at low cost.

(Third Embodiment) Next, FIGS.
A third embodiment according to the present invention will be described with reference to FIG. In this embodiment, as shown in FIG. 15, after forming an Au plating layer 21 on the surface of the outer case 10, a resist is applied thereon and partially opened,
Electrolytic plating for thickening Au is applied to the opening to selectively form an Au alloy layer 35 of Au-Fe, Au-In, Au-Ni, or the like. A Cu thick plating (electrolytic plating) is further performed on the Au alloy layer 35 to obtain C
The u plating layer 36 is formed. Then, after the resist is removed, a honing process is performed from above, and the entire surface is roughened as shown in FIG.

Next, the portion of the Au plating layer 21 not covered with the Cu plating layer 36 is removed by etching.
Next, by removing the Cu plating layer 36 by etching, as shown in FIG. 16, the Au alloy layer 35 having a mirror-finished surface and the uniformly roughened substrate extending around the Au alloy layer 35 are formed. can get.

In this embodiment, the decorative property of the exterior member can be further improved by attaching the gold alloy plating layer to the portion maintained in the mirror state. In addition, various metal layers can be formed in the mirror-finished region, not limited to the gold alloy.

In each of the embodiments described above, examples in which the present invention is basically applied to an external case for a timepiece are shown. The present invention can be applied to exterior materials and decorative materials of various articles such as a board, a watch band, a crown, a ring, a lighter, a bracelet, an earring (pierced), a pendant, a brooch, a tie pin, and a cuff button. Further, a calculator using the exterior member of the present invention,
The invention can also be applied to watches such as electronic devices such as pagers and mobile phones, electronic clocks and mechanical clocks.

[0048]

As described above, according to the present invention, the following effects can be obtained.

According to the first aspect of the present invention, by forming the metal mask to be thick, it is possible to reliably protect the surface of the exterior member during the particle spraying process, and it is possible to display a fine pattern, a symbol, and the like. Pattern can be easily formed. Further, by performing the particle spraying treatment through the thin metal layer, damage to the surface of the exterior member can be suppressed, and the surface irregularities can be smoothed, so that the corrosion resistance of the surface can be improved. .
In addition, the smoothness of the surface irregularities creates a high-quality appearance and improves the feel.

According to the second aspect, by forming the metal layer using a soft metal or alloy having high ductility, the surface of the exterior member can be protected while securing the protective effect of the surface of the exterior member during the particle spraying process. The surface can be surely roughened.

According to the third aspect, by removing the metal layer after the particle spraying process and exposing the surface of the exterior member, the surface of the exterior member is provided with a pattern, a symbol, a character, or the like due to a portion having only a different surface condition. Can be represented.

According to the fourth aspect, by leaving the surface metal layer, it is possible to construct a design having not only the surface state but also the texture and the color tone of the part formed on the peripheral rough surface. it can.

According to the fifth aspect, by performing the surface treatment by the dry film forming method, the surface condition of the exterior member is not damaged and the hardness of the surface is increased, and the texture and the color tone are changed. It becomes possible.

[Brief description of the drawings]

FIG. 1 is a schematic plan view showing the appearance of an external case of a timepiece formed by a manufacturing method according to the present invention.

FIG. 2 is a schematic sectional view showing one step of the first embodiment of the method for manufacturing an exterior member according to the present invention.

FIG. 3 is a schematic cross-sectional view showing one step of the first embodiment of the method for manufacturing an exterior member according to the present invention.

FIG. 4 is a schematic cross-sectional view showing one step of the first embodiment of the method for manufacturing an exterior member according to the present invention.

FIG. 5 is a schematic sectional view showing one step of the first embodiment of the method for manufacturing an exterior member according to the present invention.

FIG. 6 is a schematic sectional view showing one step of the first embodiment of the method for manufacturing an exterior member according to the present invention.

FIG. 7 is a schematic cross-sectional view showing one step of the first embodiment of the method for manufacturing an exterior member according to the present invention.

FIG. 8 is a schematic cross-sectional view showing one step of the first embodiment of the method for manufacturing an exterior member according to the present invention.

FIG. 9 is a schematic sectional view showing one step of the first embodiment of the method for manufacturing an exterior member according to the present invention.

FIG. 10 is a schematic sectional view showing one step of the first embodiment of the method for manufacturing an exterior member according to the present invention.

FIG. 11 is a schematic cross-sectional view showing one step of a second embodiment of the method for manufacturing an exterior member according to the present invention.

FIG. 12 is a schematic cross-sectional view showing one step of a second embodiment of the method for manufacturing an exterior member according to the present invention.

FIG. 13 is a schematic cross-sectional view showing one step of a second embodiment of the method for manufacturing an exterior member according to the present invention.

FIG. 14 is a schematic cross-sectional view showing one step of a second embodiment of the method for manufacturing an exterior member according to the present invention.

FIG. 15 is a schematic sectional view showing one step of a third embodiment of the method for manufacturing an exterior member according to the present invention.

FIG. 16 is a schematic cross-sectional view showing one step of a third embodiment of the method for manufacturing an exterior member according to the present invention.

DESCRIPTION OF SYMBOLS 10 Exterior case 10a Display window 11 Window frame part 11a Mirror surface part 11b Rough surface part 11c Coating 21 Au plating layer (metal layer) 22, 36 Cu plating layer (metal mask) 23 Resist 30 substrate 31 Mask pattern 32 Metal Mask 33 Transfer film 34 Adhesive layer 35 Au alloy layer

Claims (7)

[Claims] A step of forming a thin metal layer on the surface of the exterior member; a step of forming a partially thick metal mask on the surface of the metal layer; A method for manufacturing an exterior member, comprising: a step of performing a particle spraying process for roughening the surface of the exterior member via a metal layer; and a step of removing the metal mask. 2. The method according to claim 1, wherein the metal layer is made of Au,
A method for manufacturing an exterior member, comprising a soft or highly ductile metal or alloy such as Ni. 3. The method for manufacturing an exterior member according to claim 1, further comprising a step of removing the metal layer after the step of performing the particle spraying process. 4. The method for manufacturing an exterior member according to claim 1, further comprising: providing a surface metal layer to be left on the surface of the exterior member finally under the metal mask. 5. The method for manufacturing an exterior member according to claim 3, wherein after the metal layer and the metal mask are removed, the surface of the exterior member is subjected to a dry film forming process. 6. An electronic device comprising an exterior member formed by the manufacturing method according to claim 1. 7. A timepiece comprising an exterior member formed by the manufacturing method according to claim 1.