JP3648431B2 - Solar dial for timepiece and method for manufacturing the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a timepiece solar dial having a decorative pattern on the surface of a resin substrate and a method for manufacturing the same.
[0002]
[Prior art]
Conventionally, a timepiece solar dial used in a solar timepiece that is configured to operate by power generation of a solar cell is disposed between a transparent cover glass and a solar cell that receives external light on a light receiving surface and generates power. In order to transmit light to the solar cell, a transparent plastic material, a transparent ceramic material, or the like is often used. Of these, plastic materials are very often used for solar dials for watches because of their low cost.
[0003]
On the other hand, solar cell has a unique dark purple color tone and does not give a pleasant sensation to the appearance. Therefore, in order to make this dark purple color difficult to see, pigments and dyes are added to plastic dials (hereinafter abbreviated as plastic dials), or patterns are printed with transparent colored ink. Various methods, such as doing, were taken.
[0004]
In order to enhance the decorativeness or increase the design variation as a dial for the watch solar dial, a desired uneven pattern on the surface of the dial substrate, such as a stripe pattern, a lattice pattern, a geometric pattern, etc. Is formed.
[0005]
To obtain such a timepiece solar dial, a desired concavo-convex pattern is provided on an injection mold and transferred to a plastic dial by an injection molding method. However, this injection molding method is difficult to mold unless the thickness is 0.3 mm or more.
[0006]
Therefore, a plastic dial plate having a thickness of 0.3 mm or less employs a method of forming a desired concavo-convex pattern by a hot press method as shown in FIG. In FIG. 4, a molding apparatus 20 includes a pattern-formed upper mold 11 in which a desired concavo-convex pattern 12 is formed on an end face, and a lower mold 21 in which a flat face 22 is formed on an end face and the heater 13 is built in. Are arranged opposite to each other.
[0007]
A method for manufacturing a timepiece solar dial will be described. Since a plastic substrate used for the dial substrate is desired to be relatively hard, polycarbonate, acrylic resin, or the like is used. In the molding apparatus 20 described above, the upper mold 11 and the lower mold 21 are heated between a predetermined temperature, for example, approximately 160 ° C. to 180 ° C., between the upper mold 11 and the lower mold 21. After supplying the substrate 5, pressing is performed for a predetermined time under a predetermined pressure. After the hot pressing, the mold is opened after waiting until the temperature of the mold cools to about 110 ° C. to 120 ° C. or less, and the press-molded plastic dial substrate 2A (FIG. 5) is taken out. In the plastic dial substrate 2A shown in FIG. 5, the upper surface 11 is transferred with the concavo-convex pattern 12 formed on the upper mold 11 to transfer the desired concavo-convex pattern 2a, and the lower surface is transferred with the flat surface 22 of the lower mold 21. A flat surface 2d is formed. The pointer mounting small hole 2c disposed in the center may be formed simultaneously with pressing.
[0008]
In order to protect the desired concavo-convex pattern 2a formed on the plastic dial substrate 2A, a protective film (see FIG. 2) is formed on the upper surface with a transparent resin, and the upper surface of the protective film is made a glossy smooth surface. Finishing, a timepiece solar dial is completed by placing an index indicating a time character at a predetermined position.
[0009]
[Problems to be solved by the invention]
However, in the above-described watch solar dial and the manufacturing method thereof, the watch solar dial has a smaller thickness than the outer diameter, and the concavo-convex pattern is formed only on one side, so that it is removed from the mold. The product has a problem that warpage occurs due to the stress strain remaining in the member.
[0010]
In addition, since the lower surface side is a flat surface and the upper surface side is a concavo-convex pattern surface, there is a problem that a clear transfer pattern cannot be obtained due to occurrence of a thin transfer portion or the like due to a small resin escape space when press molding. Have.
[0011]
In order to obtain a clear transfer pattern, the pressurization temperature may be further increased. However, the product is taken out from the mold after pressing after being cooled to approximately 110 ° C. to 120 ° C. or less. In addition, there is a new problem that the cooling time takes time and workability is deteriorated.
[0012]
Therefore, a dark purple color tone of the solar cell, in which the transfer pattern is clear and warp does not occur, is relaxed, and a timepiece solar dial plate with good workability and a method for manufacturing the same are problems.
[0013]
The present invention has been made in view of the above-described conventional problems, a beautiful decorative pattern is transferred, the flatness of the dial as a molded product is ensured, the dark purple of the solar cell is not noticeable, and the workability is excellent. The present invention provides a solar dial for timepieces and a method for manufacturing the same that are optimal for a hot press method of a plastic dial having a thickness of approximately 0.3 mm or less.
[0014]
[Means for Solving the Problems]
In order to achieve the above object, the timepiece solar dial according to the present invention is a timepiece solar dial having a resin dial substrate in which a desired concavo-convex pattern is formed on the surface of a transparent resin substrate. The dial substrate has a desired concavo-convex pattern on the upper surface side and a satin pattern on the lower surface side, and the depth of the concavo-convex pattern on the upper surface side and the concavo-convex pattern on the lower surface side. The depth is set to substantially the same depth .
[0015]
DETAILED DESCRIPTION OF THE INVENTION
The timepiece solar dial and the manufacturing method thereof according to the present invention will be described below with reference to the drawings. FIG. 1 is a plan view of a timepiece solar dial according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of main parts of FIG. 1, and FIG. 3 is a cross-sectional view of main parts of a molding apparatus showing a manufacturing method.
[0016]
In FIG. 1, reference numeral 1 denotes a transparent timepiece dial. 2 is a plug dial substrate formed of polycarbonate or acrylic resin, plastics dial group 2 is a permeable certain substrate having a desired color tone, substantially as its thickness 0.2mm~0 . About 3 mm is used. 2a is a desired concavo-convex pattern formed on the upper surface side of the plastic dial substrate 2 (FIG. 1 is a lattice pattern). Various patterns such as a stripe pattern, a lattice pattern, a piage pattern, etc. can be selected. Is done. The depth of these concavo-convex patterns is approximately 10 μm to 70 μm. Reference numeral 2b denotes a satin pattern with fine irregularities formed on the lower surface side of the plastic dial substrate 2. The depth of the unevenness of the satin pattern 2b is preferably formed to be substantially the same depth as the desired uneven pattern 2a formed on the upper surface side, that is, about 10 μm to 70 μm. Reference numeral 2 c denotes a pointer attaching small hole formed at the center of the plastic dial substrate 2.
[0017]
In FIG. 2, 3 is a transparent protective film laminated | stacked on the upper surface of the desired uneven | corrugated pattern 2a. This protective film 3 is formed of a transparent resin by a method such as painting or printing, and its upper surface is polished to a glossy smooth surface, and has a function of protecting the desired uneven pattern 2a from scratches and the like. ing.
[0018]
1 and 2, 4 is an index indicating a time character. The index 4 in the present embodiment is made of metal, and is adhered and fixed to a predetermined position on the upper surface of the protective film 3 via an adhesive. The indicator may be arranged by a printing method instead of a metal member.
[0019]
A method for manufacturing the timepiece solar dial described above will be described with reference to FIG. As shown in FIG. 3, a method of forming a desired concavo-convex pattern by a hot press method is employed as in the conventional case. The upper mold 11 constituting the molding apparatus 10 has a desired concavo-convex pattern 12 formed on the end face and has a heater 13 built therein as in the conventional case. The lower mold 15 has an uneven satin pattern 16 formed on the end surface and incorporates a heater 13.
[0020]
The plastic substrate 5 used for the dial substrate is made of polycarbonate, acrylic resin, or the like as in the conventional case. In the molding apparatus 10 described above, the upper mold 11 and the lower mold 15 are heated between a predetermined temperature, for example, approximately 160 ° C. to 180 ° C. After supplying the substrate 5, pressing is performed for a predetermined time under a predetermined pressure, and the mold is opened after waiting until the temperature of the mold cools to about 110 ° C. to 120 ° C. or less. Take out. In order to protect the desired concavo-convex pattern 2a formed on the plastic dial plate substrate 2, a transparent protective film 3 is formed on the upper surface of the plastic dial substrate 2 by a method such as painting or printing, as in the prior art. Further the upper surface of the protective film 3 finished smooth surface shiny, completing the timepiece solar dial 1 by disposing the index 4 indicating a time character in place.
[0021]
In the watch solar dial 1 formed by the above method, a desired uneven pattern 2a is formed simultaneously on the upper surface side of the plastic dial substrate 2, and a satin pattern 2b is formed on the lower surface side by embossing. Since the depth is substantially the same, the stress strain remaining on the upper and lower sides is also the same, and no warpage occurs.
[0022]
Further, since both the upper and lower surfaces have irregularities, the resin can easily escape when hot pressed, and a clear and beautiful transfer pattern can be obtained even when pressed at a relatively low heating temperature.
[0023]
Furthermore, since the mold cooling time for taking out the product after pressing can be shortened, work efficiency can be improved.
[0024]
Furthermore, by providing a textured pattern with irregularities on the lower surface side, the reflected light from the solar cell is scattered, so that the dark purple color tone peculiar to the solar cell becomes light and the uncomfortable feeling is alleviated.
[0025]
Although the present embodiment has been described with respect to a timepiece solar dial, it is not limited to a timepiece solar dial, and is particularly effective in a hot press product that forms an uneven pattern on the surface of a plastic substrate of 0.3 mm or less. Is the method.
[0026]
【The invention's effect】
As described above, by forming the concave and convex patterns on the upper and lower surfaces of the transparent plastic substrate by hot pressing at the same time, a flat timepiece solar dial plate that does not warp can be obtained.
[0027]
Further, the resin flow is good and the transferability is improved, so that a desired time-varying solar dial for a timepiece can be obtained.
[0028]
Moreover, since the heating temperature at the time of hot pressing can be lowered, the cooling time can be shortened, and the workability is improved accordingly.
[0029]
Further, since the reflected light from the solar cell is scattered by the satin pattern provided on the lower surface side, it is possible to alleviate the uncomfortable feeling of the dark purple color tone unique to the solar cell.
[Brief description of the drawings]
FIG. 1 is a plan view of a timepiece solar dial according to an embodiment of the present invention.
2 is a cross-sectional view of a main part of the timepiece solar dial of FIG. 1;
FIG. 3 is a cross-sectional view of an essential part of a molding apparatus for explaining a method for manufacturing a timepiece solar dial according to an embodiment of the present invention.
FIG. 4 is a cross-sectional view of an essential part of a molding apparatus for explaining a conventional method for manufacturing a timepiece solar dial.
5 is a cross-sectional view of a main part of a plastic dial substrate manufactured by the molding apparatus of FIG. 4. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Clock face dial 2 Plastic dial board 2a Concavity and convexity pattern 2b Paste pattern 2c Pointer attachment small hole 3 Protective film 4 Indicator 5 Plastic substrate 10 Molding device 11 Upper mold 12 Concavity and convexity pattern 13 Heater 15 Lower mold 16 Patina pattern

Claims (1)

In the timepiece solar dial having a resin dial plate in which a desired concavo-convex pattern is formed on the surface of a permeable resin substrate, the resin dial plate substrate has a desired concavo-convex pattern formed on the upper surface side, A satin pattern is formed on the lower surface side, and the depth of the unevenness on the upper surface side and the depth of the unevenness on the lower surface side are set to be substantially the same depth. Solar dial for clocks.

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