EP4600759A1 - Timepiece component, timepiece, and method of manufacturing timepiece component - Google Patents

Timepiece component, timepiece, and method of manufacturing timepiece component

Info

Publication number
EP4600759A1
EP4600759A1 EP25156163.5A EP25156163A EP4600759A1 EP 4600759 A1 EP4600759 A1 EP 4600759A1 EP 25156163 A EP25156163 A EP 25156163A EP 4600759 A1 EP4600759 A1 EP 4600759A1
Authority
EP
European Patent Office
Prior art keywords
base
nonconductive
hole
nonconductive base
timepiece component
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP25156163.5A
Other languages
German (de)
French (fr)
Inventor
Koki Takasawa
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Seiko Epson Corp
Original Assignee
Seiko Epson Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Seiko Epson Corp filed Critical Seiko Epson Corp
Publication of EP4600759A1 publication Critical patent/EP4600759A1/en
Pending legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G04—HOROLOGY
    • G04B—MECHANICALLY-DRIVEN CLOCKS OR WATCHES; MECHANICAL PARTS OF CLOCKS OR WATCHES IN GENERAL; TIME PIECES USING THE POSITION OF THE SUN, MOON OR STARS
    • G04B19/00—Indicating the time by visual means
    • G04B19/06—Dials
    • G04B19/12—Selection of materials for dials or graduations markings
    • G—PHYSICS
    • G04—HOROLOGY
    • G04B—MECHANICALLY-DRIVEN CLOCKS OR WATCHES; MECHANICAL PARTS OF CLOCKS OR WATCHES IN GENERAL; TIME PIECES USING THE POSITION OF THE SUN, MOON OR STARS
    • G04B19/00—Indicating the time by visual means
    • G04B19/06—Dials
    • G04B19/10—Ornamental shape of the graduations or the surface of the dial; Attachment of the graduations to the dial

Definitions

  • the present disclosure relates to a timepiece component, a timepiece, and a method of manufacturing a timepiece component.
  • a timepiece dial disclosed in JP-T-2021-510820 includes a support and a mother-of-pearl sheet.
  • the mother-of-pearl sheet has a front surface and a rear surface.
  • the rear surface with a pattern printed thereon faces the support.
  • the thickness of the mother-of-pearl sheet is such that the pattern printed on the rear surface of the mother-of-pearl sheet can be seen through the mother-of-pearl sheet under normal illumination conditions.
  • a timepiece includes the timepiece component.
  • a method of manufacturing a timepiece component includes: preparing a conductive base and a nonconductive base separately; bonding together the conductive base and the nonconductive base; perforating the nonconductive base with a through-hole from a front surface side of the nonconductive base bonded to the conductive base, the through-hole extending at least through the nonconductive base to the conductive base; and electrolytically plating the through-hole in the nonconductive base by feeding an electric current to the conductive base while the conductive base and the nonconductive base are immersed in an electrolyte solution.
  • a method of manufacturing a timepiece component includes: preparing a conductive base and a nonconductive base separately; perforating the nonconductive base with a through-hole; bonding together the conductive base and the nonconductive base having the through-hole; and electrolytically plating the through-hole in the nonconductive base by feeding an electric current to the conductive base while the conductive base and the nonconductive base are immersed in an electrolyte solution.
  • FIG. 1 is a front view of a timepiece 1.
  • the timepiece 1 includes a dial 3, which is a timepiece component according to a first embodiment.
  • the timepiece 1 is a wristwatch that is to be worn on the user's wrist.
  • the timepiece 1 includes an outer case 2, which is cylindrical in shape.
  • the dial 3 is located in the region enclosed by the inner periphery of the outer case 2.
  • the outer case 2 is open on both sides.
  • the opening on the front side is covered with a cover glass, and the opening on the back side is closed with a case back.
  • the timepiece 1 further includes a movement (not illustrated), an hour hand 4A, a minute hand 4B, a seconds hand 4C, indices 5, and a crown 7.
  • the movement is housed in the outer case 2.
  • the hour hand 4A, the minute hand 4B, and the seconds hand 4C are hands that indicate time information.
  • the indices 5 are fixed to the dial 3.
  • the indices 5 of the timepiece 1 according to the present embodiment are Roman numerals, the indices 5 are not limited to Roman numerals and may come in various forms, including Arabic numerals and bar indices.
  • the front surface of each constituent element described below refers to a surface on the cover-glass side, and the back surface of the constituent element refers to a surface on the case-back side.
  • a conductive base 10 and a nonconductive base 20 are bonded together to constitute the dial 3.
  • the conductive base 10 is closer than the nonconductive base 20 to the back face of the timepiece 1, that is, the conductive base 10 is located on the case-back side.
  • the nonconductive base 20 is closer than the conductive base 10 to the front face of the timepiece 1, that is, the nonconductive base 20 is located on the cover-glass side.
  • the conductive base 10 is a metal plate and has a flat circular shape or any other shape that is the shape of the dial 3 viewed in plan.
  • the conductive base 10 in the present embodiment is made of brass.
  • the nonconductive base 20 is a plate made of a nonconductive material and has a flat circular shape or any other shape that is the shape of the dial 3 viewed in plan. Although it is required that the nonconductive base 20 be made of a nonconductive material, the material of the nonconductive base 20 is not limited to a particular nonconductive material.
  • the nonconductive base 20 in the present embodiment is made of mother-of-pearl. Mother-of-pearl herein refers to a plate-like member obtained by slicing a shell of a pearl oyster (e.g., Pinctada maxima) used for the culture of pearls. In some embodiments, however, the nonconductive base 20 is made of a synthetic resin, such as polycarbonate.
  • the nonconductive base 20 be a plate of, for example, mother-of-pearl or polycarbonate with light-transmissive properties.
  • the nonconductive base 20 may be made of an opaque material.
  • the nonconductive base 20 may be an insulator, such as coating or a ceramic material.
  • the surface closer than the other surface of the conductive base 10 to the nonconductive base 20 or, in other words, to the front face of the timepiece 1 is hereinafter referred to as a front surface 11.
  • the surface closer than the other surface of the nonconductive base 20 to the front face of the timepiece 1 is hereinafter referred to as a front surface 21, and the other surface closer to the conductive base 10 is hereinafter referred to as a back surface 22.
  • the front surface 11 of the conductive base 10 and the back surface 22 of the nonconductive base 20 are bonded together with double-sided tape or an adhesive.
  • the nonconductive base 20 has through-holes of three kinds denoted by 31, 32, and 33.
  • the through-holes 31, 32, and 33 extend from the front surface 21 to the back surface 22.
  • the shape of the through-holes 31, 32, and 33 viewed in plan is illustrated in FIG. 2 , which is also a sectional view of the dial 3.
  • Each through-hole 31 is in the form of a cylinder that is circular when viewed in plan.
  • the opening defined by each through-hole 31 is smaller in area than the opening defined by each through-hole 32 and is also smaller in area than the opening defined by each through-hole 33.
  • Each through-hole 32 has a large-diameter portion 321 on the front surface 21 side and a small-diameter portion 322 on the back surface 22 side.
  • the through-hole 32 has a stepped inner surface.
  • the large-diameter portion 321 and the small-diameter portion 322 are cylindrical in shape.
  • the opening defined by the large-diameter portion 321 is larger in area than the opening defined by each through-hole 31.
  • the opening defined by the small-diameter portion 322 is smaller in area than the opening defined by the large-diameter portion 321.
  • the opening defined by the small-diameter portion 322 is equal in area to the opening defined by each through-hole 31.
  • the opening defined in the front surface 21 by the through-hole 32 is larger in area than the opening defined in the back surface 22 by the through-hole 32.
  • Each through-hole 33 is shaped like a star when viewed in plan. That is, the openings on the front surface 21 side and the back surface 22 side of each through-hole 33 are each shaped like a star.
  • the through-hole 33 viewed in cross section has the same star-like shape throughout its entire depth.
  • the through-holes 31, 32, and 33 are electrolytically plated with decorative layers 41, 42, and 43, respectively.
  • the decorative layers 41, 42, and 43 are made of a material that can be deposited by electrolytic plating.
  • the decorative layers 41, 42, and 43 each may, for example, be a layer of Ag, Ni, Au, or Cr.
  • the front surface 11 of the conductive base 10 may be covered with, for example, a Cu or Ni underlayer formed by base plating, depending on what is used as the material of the conductive base 10.
  • the decorative layers 41, 42, and 43 of the dial 3 constitute groups of stars that form patterns representing constellations.
  • the decorative layers 41, 42, and 43 in the region between the 12 o'clock position and the 2 o'clock position on the dial 3 constitute a group of seven stars that form a pattern 51, which represents the Big Dipper.
  • Lines connecting the decorative layers 41, 42, and 43 are drawn on the dial 3 to help the pattern 51 resemble the image of the Big Dipper.
  • the decorative layers 42 and 43 in the region between the 7 o'clock position and the 8 o'clock position on the dial 3 constitute a group of five stars that form a pattern 52, which represents Cassiopeia.
  • Lines connecting the decorative layers 42 and 43 are drawn on the dial 3 to help the pattern 52 resemble the image of Cassiopeia.
  • the lines that connect the decorative layers 41, 42, and 43 constituting the patterns 51 and 52 may be drawn on the front surface 21 of the nonconductive base 20 by, for example, inkjet printing.
  • the lines may be formed in like manner with the through-holes 31, 32, and 33; that is, narrow through-grooves formed from the front surface 21 to the back surface 22 may be electrolytically plated with decorative layers to form the lines.
  • the conductive base 10 and the nonconductive base 20 are prepared separately in a preparation step.
  • the conductive base 10 is stamped out of a brass plate or any other metal plate.
  • a center hole for insertion of the hand shafts is also formed by stamping.
  • the dial 3 may be a dial with a date window, in which case the date window may also be formed by stamping.
  • a mother-of-pearl sheet is cut into the nonconductive base 20.
  • the nonconductive base 20 prepared in the present embodiment is equal in shape and size to the conductive base 10 when viewed in plan. As in the case with the conductive base 10, a center hole is also formed in the nonconductive base 20.
  • the front surface 11 of the conductive base 10 and the back surface 22 of the nonconductive base 20 are bonded together with double-sided tape or an adhesive in a bonding step (see FIG. 3A ).
  • the nonconductive base 20 bonded to the conductive base 10 is then perforated in a perforation step (see FIG. 3B ).
  • the through-holes 31, 32, and 33 in the front surface 21 of the nonconductive base 20 extend at least through the nonconductive base 20 to the conductive base 10.
  • the through-holes 31, 32, and 33 may be formed by, for example, laser processing, machining, or blasting. This means that an appropriate processing method may be selected on the basis of the material of the conductive base 10 and the shape and size of the through-holes 31, 32, and 33 that are to be formed.
  • an electrolytic plating step is performed (see FIG. 4 ).
  • the conductive base 10 and the nonconductive base 20 bonded together in the bonding step are cleaned or pretreated in any other predetermined manner.
  • a plating metal 62 e.g., Ni
  • the conductive base 10 and the nonconductive base 20 bonded together are then immersed in an electrolyte solution 61 in a plating bath 60.
  • an electric current is fed from a direct-current power supply 63 with its anode and cathode connected to the plating metal 62 and the conductive base 10, respectively.
  • a reduction reaction occurs at the cathode, namely, the conductive base 10, where metal ions in the electrolyte solution 61 gain electrons.
  • the plating layer grows on only part of the nonconductive base 20 or, more specifically, in the through-holes 31, 32, and 33 where the conductive base 10 is exposed and, as a result, the decorative layers 41, 42, and 43 are formed in the through-holes 31, 32, and 33.
  • the back and side surfaces of the conductive base 10 that are in contact with the electrolyte solution 61 are also coated with layers of, for example, Ni plating.
  • An oxidation reaction occurs at the anode, namely, the plating metal 62, where metal (e.g., Ni) in the anode dissolves in the electrolyte solution 61 and, as a result, metal ions are resupplied into the electrolyte solution 61.
  • the thickness of the decorative layers 41, 42, and 43 in the through-holes 31, 32, and 33 can be controlled by adjusting, for example, the duration of metal plating. With such adjustments made, the top surface of each of the decorative layers 41, 42, and 43 in the present embodiment is located between the top and bottom of the corresponding one of the through-holes 31, 32, and 33 in the penetration direction.
  • the nonconductive base 20 being disposed on the front surface side, the metallic color of the decorative layer 45 in the recessed section 352 is seen through the nonconductive base 20, that is, through the coloration of mother-of-pearl with light-transmissive properties, thus producing a softened image.
  • an electrolytic plating step is then performed.
  • the electrolytic plating step is as described above in relation to the first embodiment and will not be further elaborated on here.
  • the decorative layer 45 is formed in each through-hole 35.
  • the thickness of the decorative layer 45 can be controlled by adjusting, for example, the duration of metal plating. With such adjustments made, the top surface of the decorative layer 45 in the present embodiment is located between the top and bottom of the opening section 351 of the through-hole 35 in the penetration direction.
  • the dial 3B according to the second embodiment produces advantageous effects similar to those attainable in the first embodiment. Furthermore, the nonconductive base 20 of the dial 3B and the decorative layer 45 in the recessed section 352 on the back surface side of the nonconductive base 20 overlap each other. Adding the decorative layer 45 serving as metallic decoration to the natural coloration of a pearl oyster leads to the creation of novel designs. Thus, the dial 3B can vary widely in design and has enhanced aesthetic appearance.
  • the through-holes 35 are formed in the nonconductive base 20, and the conductive base 10 and the nonconductive base 20 are then bonded together. After that, the decorative layer 45 is formed in the through-hole 35 by electrolytic plating. This procedure provides additional degrees of flexibility in, for example, the shape of the through-holes 35, enables cost reduction, and leads to ease of manufacturing.
  • the structure of the dial that is a timepiece component is not limited to those in the embodiments described above. It is not required that the top surface (height position) of each of the decorative layers 41, 42, 43, and 45 in the through-holes 31, 32, 33, and 35 be located between the top and bottom of the corresponding one of the through-holes 31, 32, 33, and 35 as in the embodiments described above.
  • a decorative layer in the through-hole 31 is taken as an example to illustrate some variations.
  • flash plating may be used to form a decorative layer 41A, which a thin layer on the front surface 11 of the conductive base 10. As illustrated in FIG.
  • a decorative layer 41B whose top surface is flush with the front surface 21 of the nonconductive base 20 may be formed by metal plating.
  • a decorative layer 41C whose top surface is located at a level above the front surface 21 of the nonconductive base 20 may be formed.
  • the decorative layer 41C rises to a greatest height at the center of the through-hole 31 viewed in plan.
  • the top side of the decorative layer 41C is a bulge in the shape of a spherical cap.
  • the thickness (height dimension) of the decorative layers can be controlled by adjusting, for example, the duration of metal plating. Therefore, dials can come in various designs with different three-dimensional effects.
  • the nonconductive base 20 may be composed of two or more nonconductive plates bonded together. This is particularly helpful in forming the through-holes 32, the through-holes 35, or any other through-hole whose diameter changes at a point in the distance in the penetration direction. In such a case, a plate having the large-diameter portion 321 or the opening section 351 formed therein and a plate having the small-diameter portion 322 or the recessed section 352 formed therein may be bonded together. This leads to increased efficiency of perforation.
  • the shapes of the through-holes are not limited to those in the embodiments described above. For example, the through-holes each may have an inclined inner surface.
  • Such a through-hole may be shaped like a truncated cone that increases in diameter in the direction from the front surface 21 to the back surface 22 of the nonconductive base 20 or a truncated cone that decreases in diameter in the direction from the front surface 21 to the back surface 22 of the nonconductive base 20. It is not required that the through-holes viewed in plan be circular or be shaped like a star when viewed in plan.
  • the through-holes each may have a triangular, rectangular, or any other polygonal shape or may, for example, have a vehicle- or character-themed shape.
  • the through-holes or the decorative layers formed therein by electrolytic plating may, for example, constitute a grid pattern, a concentric circular pattern, a scroll pattern, or an insular pattern when viewed in plan, with the front surface of the nonconductive base 20 being exposed to view.
  • the front surface 11 of the conductive base 10 may have recesses extending from the through-holes in the nonconductive base 20.
  • the recesses in the front surface 11 of the conductive base 10 may be electrolytically plated with decorative layers. This eliminates the need to form the recessed section 352 defining a larger opening in the back surface 22 of the nonconductive base 20 in the second embodiment. The reason for this is decorative layers can be stacked on the back surface 22 side of the nonconductive base 20.
  • the design represented by the decorative layer in the small-diameter portion 322, the design represented by the nonconductive base 20 and the conductive base 10 under the large-diameter portion 321, and the design represented by the nonconductive base 20 and the conductive base 10 outside the through-hole 32 constitute a three-stage design, thus providing a design for the external appearance with a combination of three-dimensional effects and metallic decoration.
  • Examples 1 to 12 and Comparative Examples 1 to 6 in FIG. 10 are presented with the evaluation results under different conditions concerning through-holes, plating, and so on.
  • circles in the columns defining the respective conditions indicate that the conditions concerned are applicable.
  • the header "shapes of through-holes in nonconductive base" in the column defining the conditions refers to the shapes of the through-holes formed in the nonconductive base 20.
  • Those identifiable as "through-holes” are straight through-holes (e.g., the through-holes 31).
  • Those identifiable as “blind holes 3D processed” are recessed grooves that are formed by three-dimensional processing and that do not penetrate the nonconductive base 20.
  • a decorative layer cannot be formed by electrolytic plating in such a blind hole.
  • Those identifiable as “through-holes 3D processed (front surface side)" are through-holes (e.g., the through-holes 32) whose diameter changes at a point in the distance in the penetration direction in such a manner that the opening in the front surface 21 of the nonconductive base 20 is larger in area than the opening in the back surface 22 of the nonconductive base 20.
  • through-holes 3D processed (back surface side) are through-holes (e.g., the through-holes 35) whose diameter changes at a point in the distance in the penetration direction in such a manner that the opening in the front surface 21 of the nonconductive base 20 is smaller in area than the opening in the back surface 22 of the nonconductive base 20.
  • the header "thickness of decorative layers” in the column defining the conditions refers to classification by the thickness of the decorative layers that are formed in the through-holes by electrolytic plating.
  • flash color only are thin-film decorative layers (e.g., the decorative layer 41A in FIG. 8A ) formed by flash plating.
  • nonconductive base in-between height are decorative layers (e.g., the decorative layer 41 in FIG. 2 ) each with a top surface located between the top and bottom of the corresponding through-hole.
  • decorative layers e.g., the decorative layer 41C in FIG. 8C
  • decorative layers e.g., the decorative layer 41B in FIG. 8B
  • metal vapor deposition involves forming a metal film on the nonconductive base 20 by vapor deposition, not by electrolytic plating. This process forms a metal film not only in the through-holes but also on the front surface 21 of the nonconductive base 20.
  • the column header "evaluation” refers to results of evaluations performed on dials that are the timepiece components manufactured in accordance with the respective conditions.
  • the dials were subjected to sensory evaluations based on the examiner's visual perception and were evaluated for three-dimensional effects, metallic decoration, and originality.
  • three-dimensional effects the dials visually identified as exhibiting significant three-dimensional effects were evaluated as "Excellent”, the dials visually identified as exhibiting moderate three-dimensional effects were evaluated as "Good”, the dials visually identified as exhibiting slight three-dimensional effects were evaluated as "Fair”, and the dials visually identified as exhibiting no three-dimensional effects were evaluated as "Poor”.
  • the dials with easily visible metallic decoration were evaluated as “Good”, the dials with less visible metallic decoration were evaluated as “Fair”, and the dials with no visible metallic decoration were evaluated as "Poor".
  • originality the dials visually identified as exhibiting great originality were evaluated as “Excellent”
  • the dials visually identified as exhibiting moderate originality were evaluated as “Good”
  • the dials visually identified as lacking originality were evaluated as “Poor”.
  • costs the dials were evaluated by comparison of manufacturing costs.
  • the levels of the rating scale for the lowness of cost are, in ascending order: “Poor”, “Fair”, “Good”, and “Excellent”.
  • the product evaluation refers to the evaluation of product value based on the four criteria under the column header "evaluation”.
  • the levels of the rating scale for product value are, in ascending order: "Poor", “Fair”, “Good”, and "Excellent”.
  • Examples 1 to 3 varied in the thickness of the decorative layer 41 in the through-holes 31. The results of evaluation revealed that the degree of three-dimensional effects was higher for thicker decorative layers.
  • Examples 4 to 6 varied in the thickness of the decorative layer 42 in the through-holes 32. The results of evaluation revealed that thicker decorative layers produced higher degrees of three-dimensional effects. It was also found that the decorative layer thinner than the nonconductive base 20 produced enhanced three-dimensional effects, which were due to the fact that each through-hole 32 included the large-diameter portion 321 and the small-diameter portion 322.
  • Examples 7 to 9 each involved forming decorative layers in two different kinds of through-holes, that is, in the through-holes 31 and the through-holes 32.
  • Examples 7 to 9 and the corresponding one of Examples 4 to 6 yielded the same evaluation result.
  • Examples 10 to 12 varied in the thickness of the decorative layer 45 in the through-holes 35. The area of the opening section 351 exposed at the front surface of the nonconductive base 20 was small, which weakened the three-dimensional effects. Meanwhile, the decorative layer 45 in the recessed section 352 was visible through the nonconductive base 20. This feature leads to the creation of novel designs, which make the dial 3B highly original.
  • Examples 1 to 12 involved the process of electrolytic plating to form decorative layers and were thus somewhat costly. Examples 1 to 12 each provided a dial with high product value evaluated as "Good” or a dial with superior product value evaluated as "Excellent". Comparative Examples 1 to 6, in contrast, failed to increase the product value.
  • a timepiece component according to the present disclosure includes a conductive base and a nonconductive base bonded to the conductive base.
  • the nonconductive base has at least one through-hole extending from a back surface to a front surface of the nonconductive base, with the back surface being bonded to the conductive base.
  • the at least one through-hole is electrolytically plated with a decorative layer. That is, the timepiece component according to the present disclosure is obtained in the following manner.
  • the conductive base and the nonconductive base are bonded together, and the through-hole extending from the back surface to the front surface of the nonconductive base is formed.
  • the conductive base and the nonconductive base are then immersed in an electrolyte solution, with the conductive base being connected to the cathode of a direct-current power supply.
  • the timepiece component can vary widely in design and has enhanced aesthetic appearance.
  • the decorative layer on the conductive base may have a top surface located between top and bottom of the at least one through-hole.
  • the top surface of the decorative layer on the conductive base is located between the top and bottom of the through-hole, that is, below the top of the through-hole.
  • the decorative layer is thinner than the nonconductive base.
  • the decorative layer on the conductive base may have a top surface located at a level flush with or above the front surface of the nonconductive base.
  • the timepiece component disclosed herein can exhibit three-dimensional effects created by a bulge of the decorative layer.
  • the at least one through-hole may have a stepped or inclined inner surface, and an opening defined in the front surface by the at least one through-hole may be larger in area than an opening defined in the back surface by the at least one through-hole.
  • the metallic decoration of the timepiece component according to the present disclosure stands out.
  • the volume of the through-hole can be smaller in this case than in the case where the area of the opening defined by the through-hole is constant throughout the distance from the front surface to the back surface. This translates into a reduction in the amount of metal plating applied to form the decorative layer, thus leading to cost reduction.
  • the at least one through-hole may have a stepped or inclined inner surface, and an opening defined in the back surface by the at least one through-hole may be larger in area than an opening defined in the front surface by the at least one through-hole.
  • the area of the decorative layer exposed at the front surface of the nonconductive base is smaller than the area of the decorative layer exposed at the back surface of the nonconductive base, part of the nonconductive base is underlain by the decorative layer. The overlap between the nonconductive base and the decorative layer adds novel designs to the timepiece component according to the present disclosure.
  • the at least one through-hole may include a plurality of through-holes defining openings having different areas in the front surface of the nonconductive base. Provided that the through-holes defining openings having different areas are formed, different kinds of decorative layers with exposed surfaces that are different in size can be formed in the through-holes.
  • the timepiece component according to the present disclosure can vary widely in design and can also be complex in design.
  • the nonconductive base may be made of mother-of-pearl.
  • the decorative layer serving as metallic decoration is added to the natural coloration of a pearl oyster.
  • the timepiece component according to the present disclosure has enhanced aesthetic appearance.
  • the timepiece component according to the present disclosure is preferably a dial with the nonconductive base disposed on a front surface side.
  • the timepiece component according to the present disclosure is a dial that can vary widely in design and has enhanced aesthetic appearance.
  • a timepiece according to the present disclosure includes the timepiece component.
  • the timepiece according to the present disclosure is an aesthetically designed timepiece with the timepiece component having enhanced aesthetic appearance.
  • the timepiece component according to the present disclosure can vary widely in design and has enhanced aesthetic appearance.
  • the nonconductive base is perforated after the conductive base and the nonconductive base are bonded together. This means that the nonconductive base is perforated in the state in which the nonconductive base is reinforced with the conductive base.
  • a method of manufacturing a timepiece component includes: preparing a conductive base and a nonconductive base separately; perforating the nonconductive base with a through-hole; bonding together the conductive base and the nonconductive base having the through-hole; and electrolytically plating the through-hole in the nonconductive base by feeding an electric current to the conductive base while the conductive base and the nonconductive base are immersed in an electrolyte solution.
  • a decorative layer serving as metallic decoration is added to the nonconductive base of the timepiece component.
  • the timepiece component according to the present disclosure can vary widely in design and has enhanced aesthetic appearance.
  • the nonconductive base is perforated before the conductive base and the nonconductive base are bonded together. This means that the opening defined in the back surface by the through-hole can be larger in area than the opening defined in the front surface by the through-hole.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Electroplating Methods And Accessories (AREA)

Abstract

A dial that is a timepiece component includes a conductive base and a nonconductive base bonded to the conductive base. The nonconductive base has a through-hole extending from a back surface to a front surface of the nonconductive base, with the back surface being bonded to the conductive base. The through-hole is electrolytically plated with a decorative layer. The decorative layer serving as metallic decoration is added to the nonconductive base exposed at a front surface of the dial that is a timepiece component. Thus, the timepiece component can vary widely in design and has enhanced aesthetic appearance.

Description

    BACKGROUND 1. Technical Field
  • The present disclosure relates to a timepiece component, a timepiece, and a method of manufacturing a timepiece component.
    • 2. Related Art
  • A timepiece dial disclosed in JP-T-2021-510820 includes a support and a mother-of-pearl sheet. The mother-of-pearl sheet has a front surface and a rear surface. The rear surface with a pattern printed thereon faces the support. The thickness of the mother-of-pearl sheet is such that the pattern printed on the rear surface of the mother-of-pearl sheet can be seen through the mother-of-pearl sheet under normal illumination conditions.
  • The coloration of the mother-of-pearl sheet of the dial disclosed in JP-T-2021-510820 makes the dial visually appealing; nevertheless, the entire design of the dial tends to be monotonous. This leads to demands for timepiece components and timepieces that can vary widely in design and have enhanced aesthetic appearance.
    • SUMMARY
  • According to an aspect of the present disclosure, a timepiece component includes a conductive base and a nonconductive base bonded to the conductive base. The nonconductive base has at least one through-hole extending from a back surface to a front surface of the nonconductive base, with the back surface being bonded to the conductive base. The at least one through-hole is electrolytically plated with a decorative layer.
  • According to another aspect of the present disclosure, a timepiece includes the timepiece component.
  • According to still another aspect of the present disclosure, a method of manufacturing a timepiece component includes: preparing a conductive base and a nonconductive base separately; bonding together the conductive base and the nonconductive base; perforating the nonconductive base with a through-hole from a front surface side of the nonconductive base bonded to the conductive base, the through-hole extending at least through the nonconductive base to the conductive base; and electrolytically plating the through-hole in the nonconductive base by feeding an electric current to the conductive base while the conductive base and the nonconductive base are immersed in an electrolyte solution.
  • According to yet still another aspect of the present disclosure, a method of manufacturing a timepiece component includes: preparing a conductive base and a nonconductive base separately; perforating the nonconductive base with a through-hole; bonding together the conductive base and the nonconductive base having the through-hole; and electrolytically plating the through-hole in the nonconductive base by feeding an electric current to the conductive base while the conductive base and the nonconductive base are immersed in an electrolyte solution.
    • BRIEF DESCRIPTION OF THE DRAWINGS
    • FIG. 1 is a front view of a timepiece including a dial that is a timepiece component according to a first embodiment.
    • FIG. 2 is a sectional view of the dial according to the first embodiment.
    • FIG. 3A illustrates a bonding step of a method of manufacturing the dial according to the first embodiment.
    • FIG. 3B illustrates a perforation step of the method of manufacturing the dial according to the first embodiment.
    • FIG. 4 illustrates an electrolytic plating step of the method of manufacturing the dial according to the first embodiment.
    • FIG. 5 is a front view of a dial that is a timepiece component according to a second embodiment.
    • FIG. 6 is a sectional view of the dial according to the second embodiment.
    • FIG. 7A illustrates a perforation step of a method of manufacturing the dial according to the second embodiment.
    • FIG. 7B illustrates a bonding step of the method of manufacturing the dial according to the second embodiment.
    • FIG. 7C illustrates the bonding step of the method of manufacturing the dial according to the second embodiment.
    • FIG. 8A is a sectional view of a decorative layer presented as a variation.
    • FIG. 8B is a sectional view of a decorative layer presented as another variation.
    • FIG. 8C is a sectional view of a decorative layer presented as still another variation.
    • FIG. 9 is a sectional view of a decorative layer presented as yet still another variation.
    • FIG. 10 is a table in which conditions involved in Examples, conditions involved in Comparative Examples, and evaluation results are presented.
    DESCRIPTION OF EMBODIMENTS First Embodiment
  • FIG. 1 is a front view of a timepiece 1. The timepiece 1 includes a dial 3, which is a timepiece component according to a first embodiment. The timepiece 1 is a wristwatch that is to be worn on the user's wrist. The timepiece 1 includes an outer case 2, which is cylindrical in shape. The dial 3 is located in the region enclosed by the inner periphery of the outer case 2. The outer case 2 is open on both sides. The opening on the front side is covered with a cover glass, and the opening on the back side is closed with a case back. The timepiece 1 further includes a movement (not illustrated), an hour hand 4A, a minute hand 4B, a seconds hand 4C, indices 5, and a crown 7. The movement is housed in the outer case 2. The hour hand 4A, the minute hand 4B, and the seconds hand 4C are hands that indicate time information. The indices 5 are fixed to the dial 3. Although the indices 5 of the timepiece 1 according to the present embodiment are Roman numerals, the indices 5 are not limited to Roman numerals and may come in various forms, including Arabic numerals and bar indices. The front surface of each constituent element described below refers to a surface on the cover-glass side, and the back surface of the constituent element refers to a surface on the case-back side.
  • Referring to FIG. 2, a conductive base 10 and a nonconductive base 20 are bonded together to constitute the dial 3. The conductive base 10 is closer than the nonconductive base 20 to the back face of the timepiece 1, that is, the conductive base 10 is located on the case-back side. The nonconductive base 20 is closer than the conductive base 10 to the front face of the timepiece 1, that is, the nonconductive base 20 is located on the cover-glass side. The conductive base 10 is a metal plate and has a flat circular shape or any other shape that is the shape of the dial 3 viewed in plan. The conductive base 10 in the present embodiment is made of brass.
  • The nonconductive base 20 is a plate made of a nonconductive material and has a flat circular shape or any other shape that is the shape of the dial 3 viewed in plan. Although it is required that the nonconductive base 20 be made of a nonconductive material, the material of the nonconductive base 20 is not limited to a particular nonconductive material. The nonconductive base 20 in the present embodiment is made of mother-of-pearl. Mother-of-pearl herein refers to a plate-like member obtained by slicing a shell of a pearl oyster (e.g., Pinctada maxima) used for the culture of pearls. In some embodiments, however, the nonconductive base 20 is made of a synthetic resin, such as polycarbonate. It is not required that the nonconductive base 20 be a plate of, for example, mother-of-pearl or polycarbonate with light-transmissive properties. The nonconductive base 20 may be made of an opaque material. For example, the nonconductive base 20 may be an insulator, such as coating or a ceramic material.
  • The surface closer than the other surface of the conductive base 10 to the nonconductive base 20 or, in other words, to the front face of the timepiece 1 is hereinafter referred to as a front surface 11. The surface closer than the other surface of the nonconductive base 20 to the front face of the timepiece 1 is hereinafter referred to as a front surface 21, and the other surface closer to the conductive base 10 is hereinafter referred to as a back surface 22. The front surface 11 of the conductive base 10 and the back surface 22 of the nonconductive base 20 are bonded together with double-sided tape or an adhesive.
  • The nonconductive base 20 has through-holes of three kinds denoted by 31, 32, and 33. The through-holes 31, 32, and 33 extend from the front surface 21 to the back surface 22. The shape of the through-holes 31, 32, and 33 viewed in plan is illustrated in FIG. 2, which is also a sectional view of the dial 3. Each through-hole 31 is in the form of a cylinder that is circular when viewed in plan. The opening defined by each through-hole 31 is smaller in area than the opening defined by each through-hole 32 and is also smaller in area than the opening defined by each through-hole 33. Each through-hole 32 has a large-diameter portion 321 on the front surface 21 side and a small-diameter portion 322 on the back surface 22 side. The through-hole 32 has a stepped inner surface. The large-diameter portion 321 and the small-diameter portion 322 are cylindrical in shape. The opening defined by the large-diameter portion 321 is larger in area than the opening defined by each through-hole 31. The opening defined by the small-diameter portion 322 is smaller in area than the opening defined by the large-diameter portion 321. In the present embodiment, the opening defined by the small-diameter portion 322 is equal in area to the opening defined by each through-hole 31. Thus, the opening defined in the front surface 21 by the through-hole 32 is larger in area than the opening defined in the back surface 22 by the through-hole 32. Each through-hole 33 is shaped like a star when viewed in plan. That is, the openings on the front surface 21 side and the back surface 22 side of each through-hole 33 are each shaped like a star. The through-hole 33 viewed in cross section has the same star-like shape throughout its entire depth.
  • The through-holes 31, 32, and 33 are electrolytically plated with decorative layers 41, 42, and 43, respectively. The decorative layers 41, 42, and 43 are made of a material that can be deposited by electrolytic plating. The decorative layers 41, 42, and 43 each may, for example, be a layer of Ag, Ni, Au, or Cr. The front surface 11 of the conductive base 10 may be covered with, for example, a Cu or Ni underlayer formed by base plating, depending on what is used as the material of the conductive base 10.
  • As illustrated in FIG. 1, the decorative layers 41, 42, and 43 of the dial 3 according to the present embodiment constitute groups of stars that form patterns representing constellations. Specifically, the decorative layers 41, 42, and 43 in the region between the 12 o'clock position and the 2 o'clock position on the dial 3 constitute a group of seven stars that form a pattern 51, which represents the Big Dipper. Lines connecting the decorative layers 41, 42, and 43 are drawn on the dial 3 to help the pattern 51 resemble the image of the Big Dipper. The decorative layers 42 and 43 in the region between the 7 o'clock position and the 8 o'clock position on the dial 3 constitute a group of five stars that form a pattern 52, which represents Cassiopeia. Lines connecting the decorative layers 42 and 43 are drawn on the dial 3 to help the pattern 52 resemble the image of Cassiopeia. The lines that connect the decorative layers 41, 42, and 43 constituting the patterns 51 and 52 may be drawn on the front surface 21 of the nonconductive base 20 by, for example, inkjet printing. Alternatively, the lines may be formed in like manner with the through-holes 31, 32, and 33; that is, narrow through-grooves formed from the front surface 21 to the back surface 22 may be electrolytically plated with decorative layers to form the lines.
  • A method of manufacturing the dial 3, which is a timepiece component, is described below with reference to FIGs. 3A, 3B, and 4. First, the conductive base 10 and the nonconductive base 20 are prepared separately in a preparation step. For example, the conductive base 10 is stamped out of a brass plate or any other metal plate. A center hole for insertion of the hand shafts is also formed by stamping. The dial 3 may be a dial with a date window, in which case the date window may also be formed by stamping. Meanwhile, a mother-of-pearl sheet is cut into the nonconductive base 20. The nonconductive base 20 prepared in the present embodiment is equal in shape and size to the conductive base 10 when viewed in plan. As in the case with the conductive base 10, a center hole is also formed in the nonconductive base 20.
  • Then, the front surface 11 of the conductive base 10 and the back surface 22 of the nonconductive base 20 are bonded together with double-sided tape or an adhesive in a bonding step (see FIG. 3A). The nonconductive base 20 bonded to the conductive base 10 is then perforated in a perforation step (see FIG. 3B). The through-holes 31, 32, and 33 in the front surface 21 of the nonconductive base 20 extend at least through the nonconductive base 20 to the conductive base 10. The through-holes 31, 32, and 33 may be formed by, for example, laser processing, machining, or blasting. This means that an appropriate processing method may be selected on the basis of the material of the conductive base 10 and the shape and size of the through-holes 31, 32, and 33 that are to be formed.
  • Then, an electrolytic plating step is performed (see FIG. 4). In the electrolytic plating step, the conductive base 10 and the nonconductive base 20 bonded together in the bonding step are cleaned or pretreated in any other predetermined manner. Together with a plating metal 62 (e.g., Ni), the conductive base 10 and the nonconductive base 20 bonded together are then immersed in an electrolyte solution 61 in a plating bath 60. In this state, an electric current is fed from a direct-current power supply 63 with its anode and cathode connected to the plating metal 62 and the conductive base 10, respectively. A reduction reaction occurs at the cathode, namely, the conductive base 10, where metal ions in the electrolyte solution 61 gain electrons. This results in the deposition of metal and, by extension, the growth of a plating layer. The plating layer grows on only part of the nonconductive base 20 or, more specifically, in the through-holes 31, 32, and 33 where the conductive base 10 is exposed and, as a result, the decorative layers 41, 42, and 43 are formed in the through-holes 31, 32, and 33. The back and side surfaces of the conductive base 10 that are in contact with the electrolyte solution 61 are also coated with layers of, for example, Ni plating. An oxidation reaction occurs at the anode, namely, the plating metal 62, where metal (e.g., Ni) in the anode dissolves in the electrolyte solution 61 and, as a result, metal ions are resupplied into the electrolyte solution 61. The thickness of the decorative layers 41, 42, and 43 in the through-holes 31, 32, and 33 can be controlled by adjusting, for example, the duration of metal plating. With such adjustments made, the top surface of each of the decorative layers 41, 42, and 43 in the present embodiment is located between the top and bottom of the corresponding one of the through-holes 31, 32, and 33 in the penetration direction. In other words, the top surfaces of the decorative layers 41, 42, and 43 are located above the back surface 22 of the nonconductive base 20 and are not at a level flush with or above the front surface 21 of the nonconductive base 20. That is, the decorative layers 41, 42, and 43 are recessed relative to the front surface 21 of the nonconductive base 20. Upon the lapse of a plating time necessary for forming the decorative layers 41, 42, and 43, the conductive base 10 and the nonconductive base 20 are lifted out of the electrolyte solution 61 and are then subjected to a predetermined aftertreatment involving, for example, the removal of the electrolyte solution 61 left on the conductive base 10 and the nonconductive base 20. This is followed by putting finishing touches to the dial 3. For example, the indices 5 are affixed to the dial 3 to obtain the dial 3 in finished form.
    • Advantageous Effects of First Embodiment
  • The decorative layers 41, 42, and 43 serving as metallic decoration are added to the front surface 21 of the nonconductive base 20 to form the patterns 51 and 52 on the dial 3. Thus, the dial 3 can vary widely in design and has enhanced aesthetic appearance. Specifically, the decorative layers 41, 42, and 43 exposed at the front surface 21 of the nonconductive base 20 differ from each other in area and shape and can thus provide distinguishability among stars of different magnitudes when representing stars that constitute constellations. The layers of metal plating applied to the back and side surfaces of the conductive base 10 by electrolytic plating improve the corrosion resistance of the conductive base 10 that is made of brass. The decorative layers 41, 42, and 43 are formed in the following manner: the conductive base 10 and the nonconductive base 20 are bonded together, and the through-holes 31, 32, and 33 are then formed in the nonconductive base 20 and are then electrolytically plated. This enables cost reduction and leads to ease of manufacturing. The conductive base 10 and the nonconductive base 20 are bonded together before the through-holes 31, 32, and 33 are formed. This means that the through-holes are formed in the state in which the nonconductive base 20 is reinforced with the conductive base 10. This eliminates or reduces the possibility that the nonconductive base 20 will become damaged when it is perforated.
    • Second Embodiment
  • FIG. 5 is a front view of a dial 3B, which is a timepiece component according to a second embodiment. Some constituent elements of the dial 3B according to the second embodiment may be identical or similar to those of the dial 3 according to the first embodiment. Each of these elements in the second embodiment and the corresponding element in the first embodiment are denoted by the same reference sign and will not be further elaborated on here or will be described in a simplified way. The dial 3B according to the second embodiment is marked with a pattern 55, which is different from the patterns formed on the dial 3 according to the first embodiment. The pattern 55 is evocative of an image of a flower and is formed around a center hole 30 of the dial 3B. Referring to FIG. 6, the conductive base 10 and the nonconductive base 20 are bonded together to constitute the dial 3B. As in the first embodiment, the conductive base 10 is a metal plate made of, for example, brass and will not be further elaborated on here.
  • The nonconductive base 20 is made of mother-of-pearl as in the first embodiment and has through-holes 35, which extend from the front surface 21 to the back surface 22. Each through-hole 35 has an opening section 351 on the front surface 21 side and a recessed section 352 on the back surface 22 side. The opening section 351 defines an opening in the front surface 21 and includes more than one opening 351A and five openings 351B. The openings 351A are located in the midsection of the pattern 55 viewed in plan and are flat circular in shape when viewed in plan. The openings 351B extend radially from around the openings 351A and are substantially triangular in shape when viewed in plan. The recessed section 352 is a recessed groove which defines an opening in the back surface 22. When viewed in plan, the recessed section 352 has a shape evocative of an image of petals. Thus, the recessed section 352 is formed in a range larger, when viewed in plan, than a range in which the opening section 351 is formed. The opening defined in the back surface 22 by the through-hole 35 is therefore larger in area than the opening defined in the front surface 21 by the through-hole 35.
  • Each through-hole 35 is electrolytically plated with a decorative layer 45. The decorative layer 45 is made of a material that can be deposited by electrolytic plating. As in the first embodiment, the decorative layer 45 may, for example, be a layer of Ag, Ni, Au, or Cr. As in the first embodiment, the front surface 11 of the conductive base 10 may be covered with, for example, a Cu or Ni underlayer formed by base plating, depending on what is used as the material of the conductive base 10. The decorative layer 45 in the opening section 351 is exposed and directly visible on the front surface side of the dial 3B and thus takes on the color of the plating metal deposited in the opening section 351. With the nonconductive base 20 being disposed on the front surface side, the metallic color of the decorative layer 45 in the recessed section 352 is seen through the nonconductive base 20, that is, through the coloration of mother-of-pearl with light-transmissive properties, thus producing a softened image.
  • A method of manufacturing the dial 3B, which is a timepiece component, is described below with reference to FIGs. 7A, 7B, and 7C. First, the conductive base 10 and the nonconductive base 20 are prepared separately in a preparation step. The preparation step is as described above in relation to the first embodiment and will not be further elaborated on here.
  • Then, the nonconductive base 20 is perforated in a perforation step (see FIG. 7A), in which each through-hole 35 is formed by, for example, laser processing. Given that the recessed section 352 defining an opening in the back surface 22 of the nonconductive base 20 is to be larger than the opening section 351 defining an opening in the front surface 21 of the nonconductive base 20, the nonconductive base 20 can be conveniently subjected to perforation with the front surface 21 and the back surface 22 facing a machine table and a processing machine, respectively, as illustrated in FIG. 7A. The recessed section 352 on the back surface 22 side is formed ahead of the opening section 351 and can thus be larger in area than the opening section 351.
  • Then, the front surface 11 of the conductive base 10 and the back surface 22 of the nonconductive base 20 are bonded together with double-sided tape or an adhesive in a bonding step (see FIGs. 7B and 7C). Each through-hole 35 in the nonconductive base 20 in the resultant state has the recessed section 352 on the conductive base 10 side and the opening section 351 on the front surface 21 side.
  • As in the first embodiment, an electrolytic plating step is then performed. The electrolytic plating step is as described above in relation to the first embodiment and will not be further elaborated on here. As illustrated in FIG. 6, the decorative layer 45 is formed in each through-hole 35. The thickness of the decorative layer 45 can be controlled by adjusting, for example, the duration of metal plating. With such adjustments made, the top surface of the decorative layer 45 in the present embodiment is located between the top and bottom of the opening section 351 of the through-hole 35 in the penetration direction. In other words, the recessed section 352 is filled with the decorative layer 45, and the top surface of the decorative layer 45 in the opening section 351 is located above the back surface 22 of the nonconductive base 20 and is not at a level flush with or above the front surface 21 of the nonconductive base 20. In the recessed section 352, the decorative layer 45 is located on the back surface side of the nonconductive base 20, whereas in the opening section 351, the decorative layer 45 is recessed relative to the front surface 21 of the nonconductive base 20. After that, the conductive base 10 and the nonconductive base 20 are lifted out of the electrolyte solution 61 and are then subjected to a predetermined aftertreatment involving, for example, the removal of the electrolyte solution 61 left on the conductive base 10 and the nonconductive base 20. This is followed by putting finishing touches to the dial 3B. For example, the indices 5 are affixed to the dial 3B to obtain the dial 3B in finished form.
    • Advantageous Effects of Second Embodiment
  • The dial 3B according to the second embodiment produces advantageous effects similar to those attainable in the first embodiment. Furthermore, the nonconductive base 20 of the dial 3B and the decorative layer 45 in the recessed section 352 on the back surface side of the nonconductive base 20 overlap each other. Adding the decorative layer 45 serving as metallic decoration to the natural coloration of a pearl oyster leads to the creation of novel designs. Thus, the dial 3B can vary widely in design and has enhanced aesthetic appearance. The through-holes 35 are formed in the nonconductive base 20, and the conductive base 10 and the nonconductive base 20 are then bonded together. After that, the decorative layer 45 is formed in the through-hole 35 by electrolytic plating. This procedure provides additional degrees of flexibility in, for example, the shape of the through-holes 35, enables cost reduction, and leads to ease of manufacturing.
    • Variations
  • The structure of the dial that is a timepiece component is not limited to those in the embodiments described above. It is not required that the top surface (height position) of each of the decorative layers 41, 42, 43, and 45 in the through-holes 31, 32, 33, and 35 be located between the top and bottom of the corresponding one of the through-holes 31, 32, 33, and 35 as in the embodiments described above. A decorative layer in the through-hole 31 is taken as an example to illustrate some variations. As illustrated in FIG. 8A, flash plating may be used to form a decorative layer 41A, which a thin layer on the front surface 11 of the conductive base 10. As illustrated in FIG. 8B, a decorative layer 41B whose top surface is flush with the front surface 21 of the nonconductive base 20 may be formed by metal plating. As illustrated in FIG. 8C, a decorative layer 41C whose top surface is located at a level above the front surface 21 of the nonconductive base 20 may be formed. When being deposited, the decorative layer 41C rises to a greatest height at the center of the through-hole 31 viewed in plan. Thus, the top side of the decorative layer 41C is a bulge in the shape of a spherical cap. As can be seen from the decorative layers 41, 41A, 41B, and 41C, the thickness (height dimension) of the decorative layers can be controlled by adjusting, for example, the duration of metal plating. Therefore, dials can come in various designs with different three-dimensional effects.
  • As illustrated in FIG. 9, through-holes 36 may be formed in the nonconductive base 20, and a decorative layer 41D may be formed in the through-holes 36. When being deposited, the decorative layer 41D is allowed to rise above the front surface 21 of the nonconductive base 20 so that there will be no gap between the part extending over one through-hole 36 and the part extending over another through-hole 36. Thus, the decorative layer 41D formed by electrolytic plating is continuous, creating a wave-like design for the external appearance.
  • The nonconductive base 20 may be composed of two or more nonconductive plates bonded together. This is particularly helpful in forming the through-holes 32, the through-holes 35, or any other through-hole whose diameter changes at a point in the distance in the penetration direction. In such a case, a plate having the large-diameter portion 321 or the opening section 351 formed therein and a plate having the small-diameter portion 322 or the recessed section 352 formed therein may be bonded together. This leads to increased efficiency of perforation. The shapes of the through-holes are not limited to those in the embodiments described above. For example, the through-holes each may have an inclined inner surface. Such a through-hole may be shaped like a truncated cone that increases in diameter in the direction from the front surface 21 to the back surface 22 of the nonconductive base 20 or a truncated cone that decreases in diameter in the direction from the front surface 21 to the back surface 22 of the nonconductive base 20. It is not required that the through-holes viewed in plan be circular or be shaped like a star when viewed in plan. The through-holes each may have a triangular, rectangular, or any other polygonal shape or may, for example, have a vehicle- or character-themed shape. The through-holes or the decorative layers formed therein by electrolytic plating may, for example, constitute a grid pattern, a concentric circular pattern, a scroll pattern, or an insular pattern when viewed in plan, with the front surface of the nonconductive base 20 being exposed to view. The front surface 11 of the conductive base 10 may have recesses extending from the through-holes in the nonconductive base 20. The recesses in the front surface 11 of the conductive base 10 may be electrolytically plated with decorative layers. This eliminates the need to form the recessed section 352 defining a larger opening in the back surface 22 of the nonconductive base 20 in the second embodiment. The reason for this is decorative layers can be stacked on the back surface 22 side of the nonconductive base 20. Provided that the nonconductive base 20 is made of a light-transmissive material, the decorative layer in the through-hole 32 or any other through-hole having a step portion or a sloping portion may be formed by flash plating or short-time plating so that the decorative layer is deposited in the small-diameter portion 322 only. The overlapping part of the nonconductive base 20 that overlaps the large-diameter portion 321 in the thickness direction is thinner than the nonperforated part of the nonconductive base 20. Thus, the color of the material of the conductive base 10 serving as the underlayer or the color of metal applied by base plating can be seen through the thinner part of the nonconductive base 20. The design represented by the decorative layer in the small-diameter portion 322, the design represented by the nonconductive base 20 and the conductive base 10 under the large-diameter portion 321, and the design represented by the nonconductive base 20 and the conductive base 10 outside the through-hole 32 constitute a three-stage design, thus providing a design for the external appearance with a combination of three-dimensional effects and metallic decoration.
  • Examples of the timepiece component are not limited to dials. Although the timepiece component may be any constituent element of a timepiece, it is particularly preferred that the timepiece component be visible from outside the timepiece. The timepiece component may, for example, be a dial, an outer case, a bezel, a dial ring, a case back, a bracelet, a hand shaft, a train wheel bridge, or an oscillating weight.
    • Examples
  • Hereinafter, the present disclosure is described by way of examples with reference to FIG. 10. Examples 1 to 12 and Comparative Examples 1 to 6 in FIG. 10 are presented with the evaluation results under different conditions concerning through-holes, plating, and so on. Referring to FIG. 10, circles in the columns defining the respective conditions indicate that the conditions concerned are applicable. The header "shapes of through-holes in nonconductive base" in the column defining the conditions refers to the shapes of the through-holes formed in the nonconductive base 20. Those identifiable as "through-holes" are straight through-holes (e.g., the through-holes 31). Those identifiable as "blind holes 3D processed" are recessed grooves that are formed by three-dimensional processing and that do not penetrate the nonconductive base 20. A decorative layer cannot be formed by electrolytic plating in such a blind hole. Those identifiable as "through-holes 3D processed (front surface side)" are through-holes (e.g., the through-holes 32) whose diameter changes at a point in the distance in the penetration direction in such a manner that the opening in the front surface 21 of the nonconductive base 20 is larger in area than the opening in the back surface 22 of the nonconductive base 20. Those identifiable as "through-holes 3D processed (back surface side)" are through-holes (e.g., the through-holes 35) whose diameter changes at a point in the distance in the penetration direction in such a manner that the opening in the front surface 21 of the nonconductive base 20 is smaller in area than the opening in the back surface 22 of the nonconductive base 20. The header "thickness of decorative layers" in the column defining the conditions refers to classification by the thickness of the decorative layers that are formed in the through-holes by electrolytic plating. Those identifiable as "flash color only" are thin-film decorative layers (e.g., the decorative layer 41A in FIG. 8A) formed by flash plating. Those identifiable as "nonconductive base in-between height" are decorative layers (e.g., the decorative layer 41 in FIG. 2) each with a top surface located between the top and bottom of the corresponding through-hole. Those identifiable as "not thinner than nonconductive base" are decorative layers (e.g., the decorative layer 41C in FIG. 8C) thicker than the nonconductive base 20 or decorative layers (e.g., the decorative layer 41B in FIG. 8B) each with a top surface flush with the front surface 21 of the nonconductive base 20. The process herein referred to as "metal vapor deposition" involves forming a metal film on the nonconductive base 20 by vapor deposition, not by electrolytic plating. This process forms a metal film not only in the through-holes but also on the front surface 21 of the nonconductive base 20.
  • The column header "evaluation" refers to results of evaluations performed on dials that are the timepiece components manufactured in accordance with the respective conditions. The dials were subjected to sensory evaluations based on the examiner's visual perception and were evaluated for three-dimensional effects, metallic decoration, and originality. With regard to three-dimensional effects, the dials visually identified as exhibiting significant three-dimensional effects were evaluated as "Excellent", the dials visually identified as exhibiting moderate three-dimensional effects were evaluated as "Good", the dials visually identified as exhibiting slight three-dimensional effects were evaluated as "Fair", and the dials visually identified as exhibiting no three-dimensional effects were evaluated as "Poor". As for metallic decoration, the dials with easily visible metallic decoration were evaluated as "Good", the dials with less visible metallic decoration were evaluated as "Fair", and the dials with no visible metallic decoration were evaluated as "Poor". As for originality, the dials visually identified as exhibiting great originality were evaluated as "Excellent", the dials visually identified as exhibiting moderate originality were evaluated as "Good", and the dials visually identified as lacking originality were evaluated as "Poor". As for costs, the dials were evaluated by comparison of manufacturing costs. The levels of the rating scale for the lowness of cost are, in ascending order: "Poor", "Fair", "Good", and "Excellent". The product evaluation refers to the evaluation of product value based on the four criteria under the column header "evaluation". The levels of the rating scale for product value are, in ascending order: "Poor", "Fair", "Good", and "Excellent".
  • Examples 1 to 3 varied in the thickness of the decorative layer 41 in the through-holes 31. The results of evaluation revealed that the degree of three-dimensional effects was higher for thicker decorative layers. Examples 4 to 6 varied in the thickness of the decorative layer 42 in the through-holes 32. The results of evaluation revealed that thicker decorative layers produced higher degrees of three-dimensional effects. It was also found that the decorative layer thinner than the nonconductive base 20 produced enhanced three-dimensional effects, which were due to the fact that each through-hole 32 included the large-diameter portion 321 and the small-diameter portion 322. Examples 7 to 9 each involved forming decorative layers in two different kinds of through-holes, that is, in the through-holes 31 and the through-holes 32. Each of Examples 7 to 9 and the corresponding one of Examples 4 to 6 yielded the same evaluation result. Examples 10 to 12 varied in the thickness of the decorative layer 45 in the through-holes 35. The area of the opening section 351 exposed at the front surface of the nonconductive base 20 was small, which weakened the three-dimensional effects. Meanwhile, the decorative layer 45 in the recessed section 352 was visible through the nonconductive base 20. This feature leads to the creation of novel designs, which make the dial 3B highly original. Examples 1 to 12 involved the process of electrolytic plating to form decorative layers and were thus somewhat costly. Examples 1 to 12 each provided a dial with high product value evaluated as "Good" or a dial with superior product value evaluated as "Excellent". Comparative Examples 1 to 6, in contrast, failed to increase the product value. This was due to the lack of decorative layers formed in through-holes by electrolytic plating. The procedure employed in the present disclosure is as follows: the conductive base 10 and the nonconductive base 20 are bonded together, and the through-holes are then formed in the nonconductive base 20 and are electrolytically plated with decorative layers. The findings above demonstrate that the present disclosure can provide dials of great product value.
    • Summary of Present Disclosure
  • A timepiece component according to the present disclosure includes a conductive base and a nonconductive base bonded to the conductive base. The nonconductive base has at least one through-hole extending from a back surface to a front surface of the nonconductive base, with the back surface being bonded to the conductive base. The at least one through-hole is electrolytically plated with a decorative layer. That is, the timepiece component according to the present disclosure is obtained in the following manner. The conductive base and the nonconductive base are bonded together, and the through-hole extending from the back surface to the front surface of the nonconductive base is formed. The conductive base and the nonconductive base are then immersed in an electrolyte solution, with the conductive base being connected to the cathode of a direct-current power supply. As a result, a plating layer is deposited in the through-hole by electrolytic plating and is formed into the decorative layer. In this way, the decorative layer serving as metallic decoration is added to the nonconductive base of the timepiece component. Thus, the timepiece component can vary widely in design and has enhanced aesthetic appearance.
  • In the timepiece component according to the present disclosure, the decorative layer on the conductive base may have a top surface located between top and bottom of the at least one through-hole. With the decorative layer being formed in the through-hole as above, the top surface of the decorative layer on the conductive base is located between the top and bottom of the through-hole, that is, below the top of the through-hole. Thus, the decorative layer is thinner than the nonconductive base. The timepiece component disclosed herein can therefore exhibit three-dimensional effects created by a recess underlain by the decorative layer.
  • In the timepiece component according to the present disclosure, the decorative layer on the conductive base may have a top surface located at a level flush with or above the front surface of the nonconductive base. Provided that the top surface of the decorative layer is located at a level flush with or above the front surface of the nonconductive base, the timepiece component disclosed herein can exhibit three-dimensional effects created by a bulge of the decorative layer.
  • In the timepiece component according to the present disclosure, the at least one through-hole may have a stepped or inclined inner surface, and an opening defined in the front surface by the at least one through-hole may be larger in area than an opening defined in the back surface by the at least one through-hole. Provided that the area of the decorative layer exposed at the front surface of the nonconductive base is large, the metallic decoration of the timepiece component according to the present disclosure stands out. In addition, the volume of the through-hole can be smaller in this case than in the case where the area of the opening defined by the through-hole is constant throughout the distance from the front surface to the back surface. This translates into a reduction in the amount of metal plating applied to form the decorative layer, thus leading to cost reduction.
  • In the timepiece component according to the present disclosure, the at least one through-hole may have a stepped or inclined inner surface, and an opening defined in the back surface by the at least one through-hole may be larger in area than an opening defined in the front surface by the at least one through-hole. Provided that the area of the decorative layer exposed at the front surface of the nonconductive base is smaller than the area of the decorative layer exposed at the back surface of the nonconductive base, part of the nonconductive base is underlain by the decorative layer. The overlap between the nonconductive base and the decorative layer adds novel designs to the timepiece component according to the present disclosure.
  • In the timepiece component according to the present disclosure, the at least one through-hole may include a plurality of through-holes defining openings having different areas in the front surface of the nonconductive base. Provided that the through-holes defining openings having different areas are formed, different kinds of decorative layers with exposed surfaces that are different in size can be formed in the through-holes. Thus, the timepiece component according to the present disclosure can vary widely in design and can also be complex in design.
  • In the timepiece component according to the present disclosure, the nonconductive base may be made of mother-of-pearl. Provided that the nonconductive base is made of mother-of-pearl, the decorative layer serving as metallic decoration is added to the natural coloration of a pearl oyster. Thus, the timepiece component according to the present disclosure has enhanced aesthetic appearance.
  • The timepiece component according to the present disclosure is preferably a dial with the nonconductive base disposed on a front surface side. The timepiece component according to the present disclosure is a dial that can vary widely in design and has enhanced aesthetic appearance.
  • A timepiece according to the present disclosure includes the timepiece component. The timepiece according to the present disclosure is an aesthetically designed timepiece with the timepiece component having enhanced aesthetic appearance.
  • According to still another aspect of the present disclosure, a method of manufacturing a timepiece component includes: preparing a conductive base and a nonconductive base separately; bonding together the conductive base and the nonconductive base; perforating the nonconductive base with a through-hole from a front surface side of the nonconductive base bonded to the conductive base, the through-hole extending at least through the nonconductive base to the conductive base; and electrolytically plating the through-hole in the nonconductive base by feeding an electric current to the conductive base while the conductive base and the nonconductive base are immersed in an electrolyte solution. In this way, a decorative layer serving as metallic decoration is added to the nonconductive base of the timepiece component. Thus, the timepiece component according to the present disclosure can vary widely in design and has enhanced aesthetic appearance. The nonconductive base is perforated after the conductive base and the nonconductive base are bonded together. This means that the nonconductive base is perforated in the state in which the nonconductive base is reinforced with the conductive base.
  • According to yet still another aspect of the present disclosure, a method of manufacturing a timepiece component includes: preparing a conductive base and a nonconductive base separately; perforating the nonconductive base with a through-hole; bonding together the conductive base and the nonconductive base having the through-hole; and electrolytically plating the through-hole in the nonconductive base by feeding an electric current to the conductive base while the conductive base and the nonconductive base are immersed in an electrolyte solution. In this way, a decorative layer serving as metallic decoration is added to the nonconductive base of the timepiece component. Thus, the timepiece component according to the present disclosure can vary widely in design and has enhanced aesthetic appearance. The nonconductive base is perforated before the conductive base and the nonconductive base are bonded together. This means that the opening defined in the back surface by the through-hole can be larger in area than the opening defined in the front surface by the through-hole.

Claims (10)

  1. A timepiece component, comprising:
    a conductive base; and
    a nonconductive base bonded to the conductive base, wherein
    the nonconductive base has at least one through-hole extending from a back surface to a front surface of the nonconductive base, with the back surface being bonded to the conductive base, and
    the at least one through-hole is electrolytically plated with a decorative layer.
  2. The timepiece component according to claim 1, wherein the decorative layer on the conductive base has a top surface located between top and bottom of the at least one through-hole.
  3. The timepiece component according to claim 1, wherein the decorative layer on the conductive base has a top surface located at a level flush with or above the front surface of the nonconductive base.
  4. The timepiece component according to claim 1, wherein
    the at least one through-hole has a stepped or inclined inner surface, and
    an opening defined in the front surface by the at least one through-hole is larger in area than an opening defined in the back surface by the at least one through-hole.
  5. The timepiece component according to claim 1, wherein
    the at least one through-hole has a stepped or inclined inner surface, and
    an opening defined in the back surface by the at least one through-hole is larger in area than an opening defined in the front surface by the at least one through-hole.
  6. The timepiece component according to claim 1, wherein the at least one through-hole comprises a plurality of through-holes defining openings having different areas in the front surface of the nonconductive base.
  7. The timepiece component according to claim 1, wherein the nonconductive base is made of mother-of-pearl.
  8. The timepiece component according to claim 1, wherein the timepiece component is a dial with the nonconductive base disposed on a front surface side.
  9. A timepiece comprising the timepiece component according to claim 1.
  10. A method of manufacturing a timepiece component, comprising:
    preparing a conductive base and a nonconductive base separately;
    bonding together the conductive base and the nonconductive base;
    before or after the bonding step, perforating the nonconductive base with a through-hole; and
    electrolytically plating the through-hole in the nonconductive base by feeding an electric current to the conductive base while the conductive base and the nonconductive base are immersed in an electrolyte solution.
EP25156163.5A 2024-02-08 2025-02-06 Timepiece component, timepiece, and method of manufacturing timepiece component Pending EP4600759A1 (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2024017664A JP2025122306A (en) 2024-02-08 2024-02-08 Clock parts, clocks and methods for manufacturing clock parts

Publications (1)

Publication Number Publication Date
EP4600759A1 true EP4600759A1 (en) 2025-08-13

Family

ID=94598823

Family Applications (1)

Application Number Title Priority Date Filing Date
EP25156163.5A Pending EP4600759A1 (en) 2024-02-08 2025-02-06 Timepiece component, timepiece, and method of manufacturing timepiece component

Country Status (3)

Country Link
EP (1) EP4600759A1 (en)
JP (1) JP2025122306A (en)
CN (1) CN120447324A (en)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040196742A1 (en) * 2003-04-01 2004-10-07 Christophe Gouthier Dial
CN1629362A (en) * 2003-12-16 2005-06-22 精工爱普生株式会社 Decorative part, manufacturing method of decorative part, clock and part to be decorated
JP2021510820A (en) 2018-02-05 2021-04-30 モントレー・ラドー・エス アー Watch dials and methods for making them
JP2022163835A (en) * 2021-04-15 2022-10-27 セイコーエプソン株式会社 Dial for watch, and watch
WO2023012036A1 (en) * 2021-08-02 2023-02-09 Rolex Sa Method for manufacturing a timepiece component

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040196742A1 (en) * 2003-04-01 2004-10-07 Christophe Gouthier Dial
CN1629362A (en) * 2003-12-16 2005-06-22 精工爱普生株式会社 Decorative part, manufacturing method of decorative part, clock and part to be decorated
JP2021510820A (en) 2018-02-05 2021-04-30 モントレー・ラドー・エス アー Watch dials and methods for making them
JP2022163835A (en) * 2021-04-15 2022-10-27 セイコーエプソン株式会社 Dial for watch, and watch
WO2023012036A1 (en) * 2021-08-02 2023-02-09 Rolex Sa Method for manufacturing a timepiece component

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CN120447324A (en) 2025-08-08

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