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EP-4075206-B1 - TIMEPIECE DIAL, TIMEPIECE, AND METHOD FOR MANUFACTURING TIMEPIECE DIAL

EP4075206B1EP 4075206 B1EP4075206 B1EP 4075206B1EP-4075206-B1

Inventors

  • KOBAYASHI, SHOGO

Dates

Publication Date
20260506
Application Date
20220413

Claims (8)

  1. A timepiece dial (10; 70) comprising a base (7) having a first region (11) having a coating film (61) provided at a surface of the base, a second region (21; 22; 8; 23; 24, 25) where the coating film is absent, and a third region (31; 32; 33), in part of the first region, where the coating film is penetrated and the base is dug down, wherein surface roughness of the third region is smaller than surface roughness of the second region, and characterised in that the third region has a cross-sectional shape with an apex.
  2. The timepiece dial (10; 70) according to claim 1, wherein optical reflectance of a surface of the third region (31; 32; 33) is greater than optical reflectance of a surface of the second region (21; 22; 8; 23; 24, 25).
  3. The timepiece dial (10; 70) according to claim 1, wherein the third region (31; 32; 33) is surrounded by the first region (11).
  4. The timepiece dial (10; 70) according to claim 1, wherein the first region (11) is provided between the second region (21; 22; 8; 23; 24, 25) and the third region (31; 32; 33).
  5. The timepiece dial (10; 70) according to claim 1, wherein at least one of the second region (21; 22; 8; 23; 24, 25) and the third region (31; 32; 33) includes a plated layer (71; 74).
  6. The timepiece dial (10; 70) according to claim 1, wherein the coating film (61) in the first region (11) is a nonconductor.
  7. A timepiece (100; 110) comprising the timepiece dial (10; 70) according to claim 1.
  8. A method for manufacturing the timepiece dial (10; 70) according to any one of claims 1 to 6, the method comprising: preparing the base (7); forming the first region (11) where the coating film (61) is provided by painting a surface of the base; forming the second region (21; 22; 8; 23; 24, 25) where the base is exposed by radiating laser light to remove the coating film; and forming the third region (31; 32; 33) where the coating film is penetrated and the base is dug down with a cutting tool (43).

Description

The present application is based on, and claims priority from JP Application Serial Number 2021-068906, filed April 15, 2021. BACKGROUND 1. Technical Field The present disclosure relates to a timepiece dial, a timepiece including the timepiece dial, and a method for manufacturing the timepiece dial. 2. Related Art It has been proposed that the dial, which is the face of a wristwatch, is devised to enhance the decorativeness and appearance thereof. For example, JP-A-2000-155181 discloses a technique for enhancing the decorativeness of a dial by forming a variety of uneven patterns on the surface of the dial. According to JP-A-2000-155181, the dial has a configuration in which an adhesive resin layer, a thin metal film, and a transparent plate are laminated on a base substrate, and the adhesive resin layer is so coated with the thin metal film that the thin metal film follows an uneven surface formed at the surface of the adhesive resin layer. The JP-A-2000-155181 describes that a large number of uneven patterns are formed at the uneven surface of the adhesive resin layer by placing a flat plate on the resin layer, evenly pressing the flat plate against the resin layer before the resin layer is cured, and then pulling the flat plate upward to cause the flat plate to pull the surface of the resin layer. The JP-A-2000-155181 further describes that the transparent plate provided on the thin metal film amplifies the three-dimensional effect of the uneven pattern. The dial described in JP-A-2000-155181, however, has a problem of a difficulty in creating an intended uneven pattern. In detail, in the method of the related art, which depends on the viscosity of the adhesive resin layer, the material of the flat plate, the pulling speed, and other factors, the formed uneven pattern is not regular, and it is difficult to quantitatively control the positions, number, size, shape, and height of the unevenness. In other words, it is required to provide a timepiece dial having high decorativeness and excellent appearance that allow expression of an intended pattern. EP 3 709 102 A1 discloses a method of manufacturing a watchmaking or jewelry component with a ceramic base and structured decoration. According to the method, the ceramic base is provided and mirror polished and machining is then carried out to produce a surface relief, at least part of which is covered with a first layer of a first metallic or/and colored decorative treatment material, and, before or after this covering, a deep engraving is carried out with a first hollow decoration of a depth greater than the thickness of said first layer, and penetrating into said base under its surface aspect and under the recesses of said surface relief. Laser ablation of said first layer is carried out at pockets at the bottom of which the ceramic material of said base is revealed. SUMMARY According to a first aspect of the present invention, there is provided a timepiece dial according to claim 1. According to another aspect of the present invention there is provided a timepiece according to claim 7. According to still another aspect of the present invention, there is provided a method according to claim 8. Preferable features are set out in the remaining claims. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of a timepiece according to a first embodiment.FIG. 2 is a flowchart showing the procedure of a method for manufacturing a dial.FIG. 3 is a plan view of a base.FIG. 4 is an enlarged view of a mark.FIG. 5 shows processes of manufacturing the dial.FIG. 6 shows processes of manufacturing the dial.FIG. 7 is an enlarged photograph of a scale.FIG. 8 is a plan view of a timepiece according to a second embodiment.FIG. 9 is a cross-sectional view of the dial.FIG. 10 is a cross-sectional view of a variation of the dial. DESCRIPTION OF EXEMPLARY EMBODIMENTS First embodiment *** Overview of timepiece *** FIG. 1 is a plan view of a timepiece according to the present embodiment. A timepiece 100 according to the present embodiment is a three-hand analog wristwatch. The timepiece 100 is formed of a case band 5, a dial 10, a second hand 1, a minute hand 2, an hour hand 3, a crown 50, and other components. The case band 5 is a case and is made of metal, such as stainless steel or titanium. A movement (not shown) for driving the hands is accommodated behind the dial 10 in the case band 5. The dial 10 is a circular, timepiece dial having an insertion hole (not shown) provided at the center thereof. Hand shafts are inserted into the insertion hole, and the second hand 1, the minute hand 2, and the hour hand 3 are attached to the hand shafts. The dial 10 has an appearance that imitates the starry sky. In detail, a starry sky is drawn against a dark blue first region 11, which represents a night sky, as a background, with a plurality of small round stars 21, large stars 22 each formed of a star-shaped pentagon, and shallow-blind-hole-shaped circular twinkling stars 31 intersperse