JPH0948626A - Wristwatch cover glass and method of manufacturing the same - Google Patents

Abstract

(57) [Abstract] [Purpose] A method of coloring not only the surface of the glass but also the inside of the glass, and a method of decorating a new cover glass for a wristwatch that can handle a three-dimensional effect or a design with depth when combined with a dial. I will provide a. [Structure] A special crystallized glass is used as the processing material for the cover glass, and the crystallized glass molded into the shape of the cover glass is partially heat treated at a temperature around or above the softening point to obtain extremely fine crystals. After forming the nuclei, re-heat treatment is performed at a temperature slightly higher than the strain point and lower than the softening point to grow crystal nuclei to obtain a partially colored or opaque cover glass.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cover glass for a wristwatch, and particularly to widen the variety of wristwatch design designs.

[0002]

2. Description of the Related Art Conventionally, various kinds of materials for a cover glass for a wristwatch are used from a low-priced plastic material to a crystal glass (common name: blue plate, white plate, BK-7, alumina-added glass) and a high-class wristwatch. There are many sapphire glasses that use sapphire single crystals, and various materials are used as cover glass for their respective purposes.

Furthermore, in recent years, not only the difference in glass material but also the aesthetic appearance and design of the display portion, so-called printed glass, that is, a wristwatch in which the inside of the glass is decorated with organic printing or metal vapor deposition film Many cover glasses have been manufactured for a wide variety of designs and colorful colors compared to transparent cover glasses.

However, as this printed glass for wristwatches, an originally transparent glass whose inner surface is subjected to a surface treatment such as organic printing or metal vapor deposition is used. According to this method, the inner surface of the glass is colored. Since only the printing process of application is performed, the width of the design is limited to a flat display, and there is a drawback that, for example, a three-dimensional uneven display cannot be obtained. For this reason, there has been a demand for a method of coloring not only the glass surface portion but also the inside of the glass material, and a new decoration method capable of coping with a three-dimensional effect or a design of a cover glass for a wrist watch having a depth when combined with a dial.

[0005]

In view of the above problems, the present invention uses a special crystallized glass as a material for processing the cover glass, and partially crystallizes the crystallized glass molded into the shape of the cover glass. After forming an extremely fine crystal nucleus by heat treatment at a temperature around or above it, reheat it at a temperature slightly lower than the strain point and below the softening point, and grow the crystal nucleus to make it partially colored or opaque. To obtain a perfect cover glass.

[0006] In order to use this crystallized glass as a cover glass for a wristwatch, it is necessary to partially crystallize (heat-treat) even though it is a small glass with a diameter of about 30 mm and a thickness of about 1 to 3 mm, and it is necessary to heat the cooled portion and the heated portion. It is necessary to perform the crystallization treatment by dividing it into portions or by giving a certain temperature difference.

[0007]

Example 1 A manufacturing process of a cover glass of the present invention will be described with reference to FIG. First, Li ₂ O as the base material for glass
-Al ₂ O ₃ -SiO ₂ material, and a crystallized glass 1 with a transparent nucleating material (TiO ₂ ) added in a glass state, having a thickness of 2.5 mm,
Cut to an external diameter of 40 mm, place it on a preheating table, and
After heating to 0 ° C, turntable 2 of press molding machine (set temperature 4
(00 ℃) Set the glass in the center, rotate it at low speed, and heat the outer circumference with the left and right burners 3 to reach a predetermined temperature of about 830 ℃.
Heated up. At this time, heating was continued until the outer peripheral portion of the crystallized glass 1 was softened by the flame of the burner 3 (glass working area temperature). Simultaneously, a press die 4 made of a cemented carbide material (WC: tungsten carbide) having a glass-contacting surface portion mirror-finished in a shape as shown in the figure is press-formed while being heated by an electric heater. The temperature was set to about 520 ° C, which is close to the strain point temperature.

After the processing temperatures of both the crystallized glass 1 and the press die 4 have been set, the press die 4 is lowered for press forming, and pressure is applied to the softened crystallized glass 1 from above to press. The outer peripheral portion of the crystallized glass 1 is press-molded while being cooled on the inner slope of the mirror surface concave portion of the mold 4. In this press molding process, the press pressure was 15 to 20 kg / cm ² and the molding holding time was about 8 seconds.

At this time, the outer peripheral portion of the crystallized glass 1 heated by the burner 3 has reached the glass softening point or higher and is ready for press molding, and a large temperature difference occurs from the central portion. Further, at the contact point between the A portion of the press die 4 and the outer peripheral portion of the crystallized glass 1 during press forming, the glass working area temperature is rapidly cooled to the die temperature, and finally about 500 to 6
Molding was completed at 00 ° C, and milky white coloring showing that crystal nuclei were generated was observed in the outer peripheral portion of the crystallized glass by these series of steps.

The crystallized glass 1 press-molded by this procedure is heat-treated at about 550 ° C., and the outer diameter is ground into a shape (finished size φ32 mm) as shown in FIG. 1 (a: side section, b: upper surface). Then, about 320 box-shaped cover glasses (box glass 5) were prepared. All of these box glasses 5 were in a stained glass tone with a uniform outer peripheral portion, had no color variations, and had the same design and shape pattern.

Further, the completed box glass 5 was chemically strengthened by an ion exchange method to secure sufficient breaking strength as a windshield window for a wristwatch. Also, the cover glass made of the completed crystallized glass material is a cover glass with a stained glass-like design in which the central part of the glass window is transparent and the outer peripheral part is milky white, unlike the conventional cover glass in appearance. When incorporated as a windshield for a wristwatch, a unique display design with depth in the hour display was obtained.

[0012]

[Embodiment 2] As another embodiment of the present invention, a cover glass using an ultraviolet-sensitive type crystallized glass will be described with reference to FIG. First, the ultraviolet-sensitive type crystallized glass 7 is formed into a thickness of 1.5 mm and an outer diameter of φ30 mm (finished finished size), and then a mask material 6 (resist film) is screen-printed on the glass surface other than the portion to be crystallized. And irradiate the glass surface with ultraviolet rays UV from the direction perpendicular to the arrow for 3 minutes, and after removing the mask material 6 with a solvent,
It was heat-treated at a temperature of 500 to 600 ° C. to be crystallized, and the outer peripheral portion of the glass was colored brown.

In order to further increase the strength, the cover glass was chemically strengthened by an ion exchange method to secure sufficient breaking strength as a windshield for a wristwatch.

In appearance, the completed cover glass has a transparent glass center part and a brown outer peripheral part in a stained glass design, and when combined with a white dial, it has a deep color as a wristwatch display. A rich and unique design was obtained.

[0015]

INDUSTRIAL APPLICABILITY The present invention uses a special crystallized glass as a processing material for the cover glass, and partially heat-treats the crystallized glass formed into the shape of the cover glass to crystallize a part of the transparent cover glass. For example, it is possible to partially color only the outer peripheral edge of the glass, and in the appearance, a cover glass with a transparent central glass window and a stained glass outer peripheral design was obtained, and combined with the dial. At that time, a unique design with colorful depth was obtained as the wristwatch display part, which is the face of the wristwatch.

[Brief description of drawings]

FIG. 1 is a side sectional view and a top view of a watch cover glass of the present invention.

FIG. 2 is a schematic view showing a manufacturing process of a watch cover glass of the present invention.

FIG. 3 is a schematic view showing a manufacturing process of another example of the wristwatch cover glass of the present invention.

[Explanation of symbols]

 1 Crystallized glass 2 Rotating table 3 Burner 4 Press die 5 Box glass 6 Mask material 7 Crystallized glass

Claims (3)

[Claims] 1. In a windshield used for a wristwatch, a so-called cover glass, crystallized glass is used as a glass material, and a specific portion of the molded glass is heat-treated to crystallize a part of the transparent glass to obtain a glass. A cover glass for a watch, characterized in that it is partially colored in a stained tone. 2. The crystallized glass is molded and processed at a softening point temperature or higher, and in order to crystallize into fine crystals, re-heat treatment is performed at a glass strain point or higher and a softening point or lower to partially form a glass molding part. The method according to claim 1, wherein the cover glass is colored. 3. A method of manufacturing a cover glass for a wristwatch, characterized in that a part of crystallized glass is colored in a stained glass tone by using ultraviolet irradiation.