Method for decorating timepiece component and timepiece component

Abstract

To provide a method for decorating a timepiece component for improving manufacturing efficiency and decorativeness.SOLUTION: A method for decorating a timepiece component is to decorate a first surface having a decoration surface through laser processing, and the method for decorating a timepiece component includes: an inside decoration step of irradiating, with a laser beam at a first intensity, a first area including an outer peripheral edge of the decoration surface on the first surface to perform decoration at a first degree of surface roughness; and an outside decoration step of irradiating a second area outside the decoration surface with a laser beam at a second intensity higher than the first intensity to perform decoration at a second degree of surface roughness higher than the first degree of surface roughness.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a method for decorating a watch part, and to a watch part decorated by said decorating method. [Background technology]

[0002] It is known that sandblasting is used to create matte patterns on watch parts such as dials, cases, back covers, and main plates. For example, the main plates used in watches with see-through backs are visible through the transparent back cover, so their appearance must also be decorative. The main plate is the base plate that serves as the foundation for the movement, so it has multiple holes, such as holes for bearing gears and holes for screw fastening. These holes are given a mirror-finished C-face to enhance their decorativeness. Such holes are called decorative holes.

[0003] Here, when forming a matte pattern on the surface of the base plate by sandblasting, if sandblasting is performed after the decorative holes are formed, the mirror surface of the decorative holes will also become matte, so sandblasting was performed before forming the decorative holes.Because the processing of the base plate is mainly done with NC lathes, performing sandblasting before forming the decorative holes requires changing the setup of the equipment, which is not efficient in manufacturing.

[0004] Instead of sandblasting, it is possible to form a matte pattern by laser processing. For example, Patent Document 1 discloses a method for manufacturing an ornament using laser processing. According to this document, a matte pattern such as a heart is formed by irradiating a part of the plating layer on the surface of the dial with a laser beam. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2009-78494 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, Patent Document 1 does not take into consideration, for example, a laser processing method when the dial has decorative holes. In particular, there is no description or suggestion of a method of performing laser processing on the periphery of the decorative holes while leaving the gloss of the holes intact. In other words, there was a demand for a method of decorating watch components that was both efficient in production and highly decorative. [Means for solving the problem]

[0007] One embodiment of a method for decorating a watch part according to the present application is a method for decorating a watch part by laser processing a first surface having a decorative surface, and includes an inner decoration process in which a first area of ​​the first surface including the outer peripheral edge of the decorative surface is irradiated with a laser at a first intensity to decorate with a first surface roughness, and an outer decoration process in which a second area on the outside of the decorative surface is irradiated with a laser at a second intensity stronger than the first intensity to decorate with a second surface roughness higher than the first surface roughness.

[0008] One aspect of a watch component according to the present application is a watch component having a decorative surface and a first surface decorated by laser processing around the periphery of the decorative surface, wherein a first region including the outer peripheral edge of the decorative surface has a decoration with a first surface roughness, and a second region on the outside of the decorative surface has a decoration with a second surface roughness that is higher than the first surface roughness. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a rear view of the timepiece according to the first embodiment. [Diagram 2] FIG. 2 is a cross-sectional view taken along line bb in FIG. [Diagram 3] An enlarged view of part c in Figure 2. [Figure 4] FIG. [Diagram 5] FIG. 4 is a flowchart showing the flow of a method for decorating a gear train bridge. [Figure 6] FIG. 1 is a schematic diagram of a laser processing device. [Figure 7]FIG. 4 is a plan view showing the range of a first region. [Figure 8] FIG. 4 is a plan view showing an example of a scanning pattern in a first region. [Figure 9] An enlarged view of the decorative area. [Figure 10] A table showing the degree of decorative surface processing when the angle is changed. [Figure 11] FIG. 4 is a plan view showing the range of a second region. [Figure 12] FIG. 11 is a plan view showing an example of a scanning pattern in a first region according to the second embodiment. [Figure 13] FIG. 4 is a plan view showing a different example of a scanning pattern in the first region. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] EMBODIMENT 1 ***Clock Overview*** FIG. 1 is a rear view of the timepiece according to this embodiment. The timepiece 100 of this embodiment is a three-hand analog wristwatch, and FIG. 1 is a plan view of its rear surface. The timepiece 100 is a so-called see-through back wristwatch, and a transparent back cover 2 is attached to the case 1, so that the internal mechanism can be observed.

[0011] Body 1 is the case, and is made of hard metal such as titanium or stainless steel. Body 1 is roughly circular, and back cover 2 is fitted to the inner circumference of the ring-shaped wall of body 1. In addition, a crown 25 is provided on the side of body 1. Back cover 2 is made of a transparent glass material such as sapphire glass. A movement 10 for driving the hands is housed inside case 1. In Figure 1, train wheel bridge 4, which is a receiving plate for movement 10, can be seen through case back 2. A roughly circular cutout is provided on the 12 o'clock side of train wheel bridge 4, and a circular barrel 15 can be seen through this cutout.

[0012] In a preferred example, the material of the train wheel bridge 4 is brass. However, the material is not limited to brass, and any metal may be used, for example, nickel silver or a precious metal. A matte pattern 21 is applied to a surface 41, which serves as a first surface, of the train wheel bridge 4. A plurality of holes are formed in the surface 41 of the train wheel bridge 4. More specifically, a plurality of through holes 5, jewel bearing holes 6, and screw holes 7 are provided in the surface 41 of the train wheel bridge 4. The through hole 5 is a decorative hole for observing the inside of the movement 10, and a decorative surface 5a is formed around it. The decorative surface 5a is a chamfered portion that is mirror-finished. The decorative surface 5a is also called a diamond-cut surface. Parts of the gears that make up the gear train can be observed through the through hole 5.

[0013] The jewel hole 6 is a hole into which a jewel 16 that supports the rotation shaft of the gear that constitutes the train wheel is inserted, and a decorative surface 6a is also formed around the periphery thereof. The screw hole 7 is a hole through which a screw 17 for fixing the train wheel bridge 4 is inserted, and a decorative surface 7a is formed around the screw hole 7. A similar decorative surface 4a is also formed around the periphery of the train wheel bridge 4. In this way, the gear train bridge 4 has a luxurious exterior finish in which a plurality of decorative surfaces 4a, 5a, 6a, 7a having a metallic luster are scattered within a matte, pear-skin pattern 21.

[0014] FIG. 2 is a cross-sectional view of the bb section in FIG. 1, and shows a cross section of the portion passing through the through hole 5 and the stone receiving hole 6. In FIG. As shown in FIG. 2, the movement 10 is configured to include a train wheel including a plurality of gears 14 between the main plate 3 and the train wheel bridge 4. A dial 18 is attached to one surface of the main plate 3, and a second hand 11, a minute hand 12, and an hour hand 13 are attached to the center of the dial 18. Note that it is sufficient for the hands to include the minute hand 12 and the hour hand 13.

[0015] Gear 14 is provided with a rotating shaft 14b, which is inserted into and rotatably supported by jewel 16 embedded in train wheel bridge 4. More specifically, jewel 16 is inserted into jewel bearing hole 6 formed in train wheel bridge 4, and rotating shaft 14b is inserted into the central hole of jewel 16. Note that jewel 16 is also called hole stone. A similar jewel 16 is provided on the main plate 3 side, and the multiple gears 14 are rotatably supported by jewel 16 on the main plate 3 side and jewel 16 on the train wheel bridge 4 side. The jewel 16 is driven into the jewel receiving hole 6 from the rear surface 42 of the train wheel bridge 4 so as not to damage the decorative surface 6a.

[0016] Fig. 3 is an enlarged view of part c in Fig. 2, showing a cross section of the through hole 5. Fig. 4 is a plan view of the through hole. As shown in FIG. 3, the decorative surface 5a is provided on the surface 41 side of the through hole 5. The angle θ between the surface 41 of the train wheel bridge 4 and the decorative surface 5a is, for example, 40°. The angle θ is also referred to as the decorative surface angle θ. The peripheral edge of the decorative surface 5a is referred to as the outer periphery 5b. As shown in FIG. 4, the diameter of the through hole 5 is a diameter φ1, and the diameter of the outer periphery 5b of the decorative surface 5a is a diameter φ3 that is larger than the diameter φ1.

[0017] As described above, the surface 41 of the train wheel bridge 4 is provided with a textured pattern 21, and the decorative surface 5a is mirror-finished. When providing such a pattern on both surfaces, typically the textured pattern 21 is formed on the train wheel bridge 4 with the through-hole 5 by sandblasting, and then the decorative surface 5a is formed. This is because if sandblasting is performed after the decorative surface 5a is formed, the decorative surface 5a will also be textured. This method also makes it possible to provide the above pattern, but after sandblasting with a dedicated device, it is necessary to set the train wheel bridge 4 again on a processing device such as a lathe, which requires frequent setup changes and poor work efficiency. In contrast, according to the decorating method of the present embodiment described below, decorating can be performed efficiently with minimal changeover.

[0018] ***How ​​to decorate the gear train bridge*** Fig. 5 is a flow chart showing the flow of a method for decorating a gear train bridge. Fig. 6 is a schematic diagram of a laser processing device. Fig. 7 is a plan view showing the range of a first region. Fig. 8 is a plan view showing an example of a scanning pattern in the first region. Here, a method of decorating the gear train bridge 4 will be explained mainly with reference to FIG. 5, and with other drawings as appropriate.

[0019] In step S11, the train wheel holder 4 is prepared after being machined to have a decorative surface. In a preferred embodiment, a machining center is used as the processing device. A surface-mounted board on which multiple train wheel holders 4 are mounted is set in the machining center, and the through holes 5, jewel receiving holes 6, and screw holes 7 are drilled, the outer shape is cut out, and then the decorative surfaces 4a, 5a, 6a, and 7a are formed. The decorative surfaces 4a, 5a, 6a, and 7a are polished to a mirror finish.

[0020] In step S12, the imposition board on which the multiple gear train holders 4 are imposed is set in a laser processing device. First, the configuration of the laser processing device 90 shown in FIG. The laser processing device 90 comprises a laser oscillator 81, a transmission optical system 82, an irradiation unit 83, a processing table 85, a control device 87, and the like. An infrared laser oscillator is used as the laser oscillator 81. In a preferred embodiment, a solid-state laser oscillator compatible with a nanosecond laser is used. However, the present invention is not limited to this, and any infrared laser oscillator may be used, and oscillators such as a gas laser, a semiconductor laser, or a liquid laser may also be used. The transmission optical system 82 is an optical path that transmits the laser light generated by the laser oscillator 81 to the irradiation unit 83, and is configured to include a plurality of reflecting mirrors.

[0021] The irradiation unit 83 is an irradiation nozzle that focuses laser light and irradiates the workpiece, and includes a focusing lens. The processing table 85 is an XY table, and moves the placed workpiece in a plane according to the scanning path pattern of the laser irradiation in accordance with instructions from a control device 87. As shown in FIG. 6, an imposition board 71 with three gear train receivers 4 imposed thereon is set on the processing table 85. The number of impositions is not limited to three, and any number can be used. The processing table 85 is provided with a pair of positioning pins (not shown) corresponding to the pair of reference holes 43 of the imposition board 71, and the imposition board 71 is fixed in a positioned state by the pair of positioning pins.

[0022] The control device 87 is a controller for the laser processing device 90, and is configured to include one or more processors, and controls the operation of each part. The control device 87 is equipped with a storage unit 88 including a non-volatile memory. The storage unit 88 stores a control program for controlling the operation of the laser processing device 90, various data, and the like. The various data stores data such as irradiation conditions for each processing portion and scanning patterns. The irradiation conditions include parameters such as energy density, output frequency, scanning speed, laser output, and scanning path pitch.

[0023] In step S13, a laser is irradiated onto the first region 31 including the outer circumferential edge 5b of the decorative surface 5a. Note that irradiating the first region 31 with a laser is also referred to as an inner decoration step. As shown in FIG. 7, the first region 31 is an annular region surrounded by an inner boundary 31a surrounding the through hole 5 and an outer boundary 31b surrounding the outer peripheral edge 5b of the decorative surface 5a. In a preferred embodiment, the dimension between the inner boundary 31a and the outer peripheral edge 5b is the same as the dimension between the outer peripheral edge 5b and the outer boundary 31b, but this is not limited thereto. The inner boundary 31a may be set within the surface of the decorative surface 5a, and the outer boundary 31b may be larger than the outer peripheral edge 5b of the decorative surface 5a. In particular, it is preferable that the outer boundary 31b is set to include the outer peripheral edge 5b of the decorative surface 5a, taking into account the processing tolerance of the decorative surface 5a. In a preferred embodiment, the outer boundary 31b is set to be larger than the maximum tolerance of the decorative surface 5a. The maximum tolerance includes the irradiation accuracy of the laser irradiation. In other words, the first region 31 is set to include the outer peripheral edge 5b of the decorative surface 5a, taking into account the processing tolerance of the decorative surface 5a.

[0024] In a preferred embodiment, the first region 31 is irradiated with a laser in a scanning pattern 51 as shown in Fig. 8. The scanning pattern 51 irradiates the first region 31 with a laser by sequentially rotating annular scanning line 52 along the outer circumferential edge 5b of the decorative surface 5a. The diameter φ2 of the scanning line 52 is set to be larger than the diameter φ1 of the through hole 5 and smaller than the diameter φ3 of the outer circumferential edge 5b of the decorative surface 5a. The center of the annular scanning line 52 is along the circumference of the imaginary circle 19 of radius r1 from the center of the through hole 5, and irradiation starts with a scanning line 52a centered at 0° on the 12 o'clock side of the imaginary circle 19. When the scanning by the scanning line 52a is completed, next, irradiation is performed by a scanning line 52b centered at 45° of the imaginary circle 19. Next, irradiation is performed by a scanning line 52c centered at 90° of the imaginary circle 19. Although not shown in the figure, next, a scanning line centered at 135° of the imaginary circle 19, a scanning line centered at 180°, and so on, scanning up to 360° in 45° increments. This completes one scanning pattern 51.

[0025] Here, for ease of explanation, an example has been described in which the angle of the scanning line 52 is in increments of 45°, but this is not limited to this, and the angle of the scanning line 52 may be appropriately set in increments of 3° or more and 15° or less.

[0026] Fig. 9 is an enlarged view of the periphery of the decorative surface, and is an enlarged view of the periphery of the decorative surface 5a on the right side in Fig. 3. Fig. 10 is a table showing the degree of processing of the decorative surface when the angle is changed. As shown in Fig. 9, when the first region 31 is irradiated with a laser, most of the irradiated light on the outer boundary 31b side is absorbed by the surface 41 of the train wheel bridge 4, processing the surface 41. On the other hand, most of the irradiated light on the inner boundary 31a side is reflected by the mirror-finished decorative surface 5a. The degree of reflection varies depending on the angle θ of the decorative surface 5a and the energy density of the laser irradiation. Table 95 in FIG. 10 shows the relationship between the angle θ of the decorative surface 5a and the energy density (mJ / cm 2 ) was changed. In Table 95, "Good" indicates that the decorative surface 5a was not processed even when irradiated with a laser and maintained a mirror finish, while "Bad" indicates that the decorative surface 5a was processed and roughened by the laser irradiation.

[0027] As shown in Table 95, the energy density is 570 to 850 mJ / cm 2 It can be seen that in this range, even if the angle θ of the decorative surface 5a is changed between 15° and 80°, the decorative surface 5a is not processed. On the other hand, the energy density is 1020mJ / cm 2 In this case, it can be seen that the decorative surface 5a is processed when the angle θ of the decorative surface 5a is 15°. Similarly, when the energy density is 1130 mJ / cm 2 Then, when the angle θ of the decorative surface 5a becomes 20° or less, the decorative surface 5a is processed and the energy density becomes 1410 mJ / cm 2 In this case, when the angle θ of the decorative surface 5a becomes 30° or less, the decorative surface 5a is processed. From these findings, it can be seen that there is a correlation between the angle θ of the decorative surface 5a and the energy density of the laser irradiation, and that by increasing the angle θ of the decorative surface 5a, processing of the decorative surface 5a can be prevented even if the energy density is high.

[0028] As mentioned above, the decorative surface 5a is part of the decorative pattern of the gear train bridge 4, and in order to ensure its design, the angle θ of the decorative surface 5a is preferably greater than or equal to 20° and less than or equal to 80°, and more preferably greater than or equal to 20° and less than or equal to 60°. The energy density as the first intensity of the laser irradiation with respect to the angle θ of the decorative surface 5a is set to 500 mJ / cm 2 in consideration of the above correlation. 2 Below 1500mJ / cm 2 In other words, the first intensity in the laser irradiation to the first region 31 is preferably an energy density of 500 mJ / cm 2 Below 1500mJ / cm 2 The irradiation conditions other than the energy density are, for example, a frequency of 600 kHz, a scanning speed of 3000 mm / sec, a pulse width of 4 ns, and a spot diameter of 30 μm. However, the conditions are not limited to these. In other words, in the inside decoration process, a laser is irradiated at a first intensity to a first region 31 including the outer peripheral edge 5b of the decorative surface 5a on the surface 41 of the train wheel bridge 4, and decoration is performed with a first surface roughness. The pulse width of the laser irradiation is not limited to nanoseconds, and may be either picoseconds or femtoseconds.

[0029] FIG. 11 is a plan view showing the range of the second region, and corresponds to FIG. 5, a laser is irradiated onto the second region 61. The irradiation of the laser onto the second region 61 is also referred to as an outside decoration step. As shown in Fig. 11, the second region 61 is an area outside the decorative surface 5a and does not include the outer peripheral edge 5b of the decorative surface 5a. In Fig. 11, only the inner boundary 61a of the second region 61 is shown. The inner boundary 61a is a concentric circle of the through hole 5, and its outer circumference is larger than the outer peripheral edge 5b of the decorative surface 5a and smaller than the outer boundary 31b of the first region 31. The second region 61 is an area on the surface 41 of the gear train bridge 4 outside the inner boundary 61a. The second region 61 has an overlapping portion 65 that overlaps with the first region 31. The overlapping portion 65 is a portion where the inner boundary 61a of the second region 61 extends inside the outer boundary 31b of the first region 31. In other words, the second region 61 includes the overlapping portion 65 that overlaps with the outer boundary 31b of the first region 31.

[0030] The laser irradiation to the second region 61 is performed at a second intensity that is stronger than the first intensity. In other words, the second intensity has a higher energy density than the first intensity. The scanning pattern is, for example, a scanning pattern that irradiates in a spiral shape from the inner boundary 61a to the outside. As a result, the surface 41 of the train wheel bridge 4 in the second region 61 is decorated with a second surface roughness that is higher than the first surface roughness. Note that the scanning pattern is not limited to this, and any scanning pattern that can irradiate the second region 61 evenly may be used. In other words, in the outer decoration step, the second region 61 on the outer side of the decorative surface 5a is irradiated with a laser at a second intensity stronger than the first intensity, and decoration is performed with a second surface roughness higher than the first surface roughness.

[0031] Generally, when laser processing is used to decorate the outside of the decorative surface 5a with a matte pattern 21, the laser is irradiated while avoiding the area of ​​the decorative surface 5a including the processing tolerance, but this method leaves a ring-shaped unprocessed area around the decorative surface 5a. Since this unprocessed area is a cut surface, it has a glaring appearance and impairs the design. In contrast, according to the decoration method of the present embodiment, by providing an overlapping portion 65 between the second region 61 and the first region 31, there is no unprocessed portion with cutting marks, and therefore glare caused by cutting marks can be prevented.

[0032] In the above, the decorative surface 5a of the through hole 5 has been described as an example of a decorated portion, but the decorative surface 6a of the stone receiving hole 6 and the peripheral portion of the decorative surface 7a of the screw hole 7 are also decorated in the same manner. The peripheral portion of the decorative surface 4a in the external shape of the train wheel bridge 4 is also decorated in the same manner. In detail, the region including part of the decorative surface 4a and the outer peripheral edge of the decorative surface 4a is defined as the first region, and the region outside the outer peripheral edge of the decorative surface 4a that has an overlapping portion that overlaps with the first region is defined as the second region, and the above-mentioned inner decoration process and outer decoration process can be performed.

[0033] ***Surface Roughness Index*** Return to Figure 4. Here, the surface roughness indexes will be described. In this embodiment, Sa value, Sdq value, and Sdr value are used as the surface roughness indexes. The Sa value is the average height difference of the surface irregularities from the average plane. The Sdq value is the average local gradient of the surface. The Sdr value is a value that represents the rate of increase in surface area. First, the surface roughness of the mirror surface of the decorative surface 5a can be expressed by these indices as "Sa: 0.027 μm," "Sdq: 0.521," and "Sdr: 0.128." Similarly, the second surface roughness of the surface 41 of the train wheel bridge 4 on which the pattern 21 is formed is "Sa: 0.232 μm", "Sdq: 2.079", and "Sdr: 1.483".

[0034] The surface roughness of the surface 41 of the train wheel bridge 4, in the state where the cutting marks remain before the laser processing, is "Sa: 0.097 μm", "Sdq: 1.109", and "Sdr: 0.502". The first surface roughness is greater than the surface roughness of the surface 41 having the cutting traces and is smaller than the second surface roughness. Note that these are merely examples and are not limited to these numerical values. For example, the first surface roughness may be a surface roughness that can suppress glare caused by the cutting traces.

[0035] As described above, the method for decorating a timepiece part and the train wheel bridge 4 as a timepiece part of this embodiment provide the following effects. The method of decorating the train wheel bridge 4 as a timepiece component is a method of decorating a surface 41 as a first surface of the train wheel bridge 4 having a decorative surface 5a by laser processing, and includes an inner decoration process in which a first area 31 including the outer peripheral edge 5b of the decorative surface 5a on the surface 41 is irradiated with a laser at a first intensity to decorate with a first surface roughness, and an outer decoration process in which a second area 61 on the outside of the decorative surface 5a is irradiated with a laser at a second intensity stronger than the first intensity to decorate with a second surface roughness higher than the first surface roughness.

[0036] According to this, after the mirror finishing of the decorative surface 5a is performed at the machining center, the matte pattern 21 can be applied to the surface 41 of the train wheel bridge 4 using only a laser processing device, completing the train wheel bridge 4. Therefore, unlike the conventional method which required decoration with a sandblasting processing device after processing at the machining center and then a change of setup to the machining center again, only one change of setup to the laser processing device is required, thereby reducing the number of setup steps. Furthermore, by providing an overlapping portion 65 between the second region 61 and the first region 31, the overlapping portion 65 functions as a buffer region, and glare caused by cutting marks remaining on the surface 41 of the gear train bridge 4 can be prevented. Therefore, it is possible to provide a method for decorating highly decorative timepiece components with good production efficiency.

[0037] The first intensity of the laser irradiation on the first region 31 is an energy density of 500 mJ / cm 2 Below 1500mJ / cm 2 The following is the result. This allows decoration with a first surface roughness to be applied to the first region 31 without impairing the mirror finish of the decorative surface 5a.

[0038] Moreover, the second intensity in the laser irradiation on the second region 61 has a higher energy density than the first intensity. This allows the second region 61 to be efficiently decorated with the second surface roughness.

[0039] In addition, the first region 31 is set to include the outer peripheral edge 5b of the decorative surface 5a, taking into account the processing tolerance of the decorative surface 5a, and the second region 61 includes an overlapping portion 65 that overlaps with the outer boundary 31b of the first region 31. This makes it possible to prevent glare caused by cutting marks remaining on the surface 41 of the train wheel bridge 4 due to missed processing between the first region 31 and the second region 61.

[0040] Moreover, the laser irradiation to the first region 31 is performed by pulse width control, and the pulse width includes any one of nanoseconds, picoseconds, and femtoseconds. This allows decoration with a first surface roughness to be applied to the first region 31 without impairing the mirror finish of the decorative surface 5a.

[0041] In addition, the train wheel bridge 4 as a watch component is a watch component having a decorative surface 5a and a surface 41 as a first surface that is decorated by laser processing around the periphery of the decorative surface 5a, and the first region including the outer peripheral edge 5b of the decorative surface 5a has a decoration with a first surface roughness, and the second region 61 on the outside of the decorative surface 5a has a decoration with a second surface roughness that is higher than the first surface roughness. According to this, the gear train bridge 4 has a luxurious appearance finished with a matte pear-skin pattern 21 and a plurality of decorative faces 5a with metallic luster scattered throughout. Therefore, it is possible to provide the train wheel bridge 4 as a highly decorative timepiece component.

[0042] Moreover, the decorative surface 5a is an inclined surface inclined relative to the surface 41 of the train wheel bridge 4 as the first surface, and the first surface roughness of the first region 31 on the surface 41 is higher than the surface roughness of the inclined surface of the decorative surface 5a. This makes it possible to provide a buffer region of the first surface roughness around the decorative surface 5a.

[0043] Moreover, the decorative surface 5a is an inclined surface inclined with respect to the surface 41 of the train wheel bridge 4, and the angle θ of the inclined surface is equal to or greater than 20° and equal to or less than 80°. This ensures the design of the decorative surface 5a, which is part of the decorative pattern of the gear train bridge 4.

[0044] The decorative surface 5a is provided around the through hole 5 formed in the surface 41 of the gear train bridge 4, and the first region 31 is a ring-shaped region that is concentric with the through hole 5 and surrounds the decorative surface 5a. This makes it possible to provide a train wheel bridge 4 having a through hole 5 with a decorative surface 5a around its periphery.

[0045] EMBODIMENT 2 ***Different Scanning Patterns*** 12 and 13 are plan views showing an example of a scanning pattern in the first region according to the second embodiment, and correspond to FIG. In the above embodiment, the laser irradiation to the first region is described as using a scanning pattern 51 in which an annular scanning line 52 rotates sequentially along the outer periphery 5b of the decorative surface 5a, but this is not limited thereto, and irradiation with a straight scanning line is also acceptable. Hereinafter, the same parts as those in the above embodiment are given the same numbers, and duplicated explanations will be omitted.

[0046] 12, only the inner boundary 31a of the first region 35 is shown. Note that the inner boundary 31a is the same as the inner boundary 31a of the first region 31. In other words, the first region 35 is the region on the surface 41 of the gear train bridge 4 outside the inner boundary 31a. 12, the first region 35 is irradiated with the laser in a scanning pattern 55. The scanning pattern 55 irradiates the first region 35 with the laser by alternately repeating scanning from the 12 o'clock side (upper side) to the 6 o'clock side (lower side) of the straight scanning line 53 and scanning from the 6 o'clock side to the 12 o'clock side while moving to the right.

[0047] First, in the scanning line 53a, the laser is irradiated from above to below on the left side of the decorative surface 5a, and in the scanning line 53b, the laser is irradiated from below to above on the right side of the scanning line 53a. Next, in the scanning line 53c, the laser is irradiated from above to below on the right side of the scanning line 53b, and in the scanning line 53d, the laser is irradiated from below to above on the right side of the scanning line 53c. Note that in the scanning line 53d, the laser irradiation is stopped within the inner boundary 31a. Similarly, in the scanning lines 53e to 53g, the laser is not irradiated within the inner boundary 31a, but is irradiated vertically within the first region 35. In this manner, in the scanning pattern 55, the periphery of the through-hole 5 is alternately scanned upward and downward with the straight scanning line 53, except within the inner boundary 31a, so that the first region 35 is irradiated with the laser.

[0048] Even with this scanning pattern 55, similarly to the scanning pattern 51, it is possible to impart decoration with a first surface roughness to the first region 35 without impairing the mirror finish of the decorative surface 5a.

[0049] Furthermore, the laser irradiation to the first region 35 may be performed according to a scanning pattern 56 shown in Fig. 13. Scanning pattern 56 is the same as scanning pattern 55 in that straight scanning lines 54 are alternately scanned while moving up, down, and to the right, but differs from scanning pattern 55 in that the laser is also irradiated within the inner boundary 31a. As mentioned above, much of the light irradiated onto the decorative surface 5a is reflected by the mirror-finished decorative surface 5a, so even with this scanning pattern 56, similar to scanning pattern 51, it is possible to decorate the first region 35 with a first surface roughness without damaging the mirror finish of the decorative surface 5a.

[0050] ***Variations*** Return to Figure 5. In the above decoration method, a cleaning step may be performed to remove debris such as cutting powder and dust adhering to the surface 41 of the train wheel bridge 4 prior to the inside decoration step in which the first region is laser-processed. In the cleaning step, the surface 41 of the train wheel bridge 4, including the decorative surface, is irradiated with a laser at an energy density weaker than the first intensity. Note that most of the irradiated light irradiated to the decorative surface is reflected, so the mirror finish of the decorative surface is maintained. Generally, when debris is attached, cleaning is performed in a separate process (separate device) such as washing with water, but according to this method, the cleaning process can also be performed in the laser processing device 90, eliminating the need to change the setup of the device and improving manufacturing efficiency.

[0051] In the above embodiment, the outer decoration process is performed by laser processing the second region after the inner decoration process is performed by laser processing the first region, but the order of the processes may be reversed. Specifically, the inner decoration process may be performed after the outer decoration process. Even in this order, since an overlapping portion 65 is provided between the second region 61 and the first region 31, glare caused by cutting marks remaining on the surface 41 of the train wheel bridge 4 can be prevented.

[0052] Return to Figure 4. In the above embodiment, the pattern 21 decorated on the surface 41 of the train wheel bridge 4 has been described as having a matte finish, but this is not limited thereto and may be set according to the design, and the pattern 21 may be, for example, a striped or circular grained pattern. In other words, the pattern 21 formed by decorating the second surface roughness includes at least any one of matte finish, striped finish, and circular grain. In addition, in the above embodiment, the train wheel bridge 4 is used as the timepiece part, but this is not limited to this, and any timepiece part on which a pattern can be formed can be used, such as a dial, oscillating weight, case, back cover, bezel, or band. [Explanation of symbols]

[0053] 1...body, φ1...diameter, φ2...diameter, φ3...diameter, r1...radius, 2...back cover, 3...base plate, 4...wheel train bridge, 4a...decorative surface, 5...through hole, 5a...decorative surface, 5b...periphery, 6...jewel hole, 6a...decorative surface, 7...screw hole, 7a...decorative surface, 10...movement, 11...second hand, 12...minute hand, 13...hour hand, 14...gear, 14b...rotating shaft, 15...barrel, 16...jewel, 17...screw, 18...dial, 19...virtual circle, 21...pattern, 25...crown, 31...first area, 31a...inner boundary, 31b...outer boundary, 35...first area , 41...surface, 42...back, 43...reference hole, 51...scanning pattern, 52...scanning line, 52a to 52c...scanning lines, 53...scanning lines, 53a to 53e...scanning lines, 55...scanning pattern, 56...scanning pattern, 54...scanning line, 61...second region, 61a...inner boundary, 65...overlapping portion, 71...imposition board, 81...laser oscillator, 82...transmission optical system, 83...irradiation unit, 85...processing table, 87...control device, 88...memory unit, 90...laser processing device, 95...table, 100...clock.

Claims

1. A method for decorating a watch component by laser processing a first surface having a decorative surface, comprising: irradiating a first region of the first surface, including an outer periphery of the decorative surface, with a laser beam at a first intensity; an inner decorating step of decorating with a first surface roughness; an outer decoration process of irradiating a second region outside the decorative surface with a laser at a second intensity stronger than the first intensity to decorate with a second surface roughness higher than the first surface roughness; A method for decorating a watch part, comprising:

2. The first intensity has an energy density of 500 mJ / cm or more and 1500 mJ / cm or less. The method for decorating a watch part according to claim 1.

3. the second intensity has a higher energy density than the first intensity; The method for decorating a watch part according to claim 2.

4. the first region is set as a region including a first inner boundary located inside an outer circumferential edge of the decorative surface and a first outer boundary located outside the outer circumferential edge, taking into consideration a processing tolerance of the decorative surface; a second inner boundary of the second region is set between the outer peripheral edge and the first outer boundary; The second region is disposed between the second inner boundary and the first outer boundary, and the inner decoration and the outer decoration step, The method for decorating a watch part according to claim 2.

5. After the outer decoration step, the inner decoration step is carried out. The method for decorating a watch part according to claim 1.

6. The laser irradiation is performed by pulse width control, The pulse width includes any one of nanoseconds, picoseconds, and femtoseconds. The method for decorating a watch part according to claim 1.

7. A timepiece component having a first surface including a decorative surface and decorated by laser processing around the periphery of the decorative surface, a first region including an outer peripheral edge of the decorative surface has a first decoration having a first surface roughness; a second region disposed outside the outer peripheral edge of the decorative surface has a second decoration having a second surface roughness higher than the first surface roughness; Watch parts.

8. the decorative surface is an inclined surface inclined with respect to the first surface, the first surface roughness of the first surface located outside the outer circumferential edge and inside the second region in the first region is higher than the surface roughness of the inclined surface of the decorative surface; The timepiece component according to claim 7.

9. The laser processing device further includes an overlapping portion disposed between the first decoration and the second decoration, the overlapping portion having undergone both the laser processing for forming the first decoration and the laser processing for forming the second decoration. The timepiece component according to claim 7.

10. the decorative surface is an inclined surface inclined with respect to the first surface, The angle of the inclined surface is equal to or greater than 20° and equal to or less than 80°. The timepiece component according to claim 7.

11. The pattern formed by decorating the second surface roughness includes at least one of a matte finish, a grained finish, and a circular grain.

9. A watch component according to claim 7 or 8.

12. the decorative surface is provided around a hole formed in the first surface, The first region is a circular region that is concentric with the hole and surrounds the decorative surface.

9. A watch component according to claim 7 or 8.

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