Method for decorating dial face, dial face, and timepiece

Abstract

To provide a dial face which is thin and is decorated to present a 3D appearance.SOLUTION: The dial face includes: a recessed part formed by laser radiation; a first trench formed by laser radiation in the bottom of the recessed part, the first trench extending in a first direction; a second trench extending in a second direction vertical to the first direction; and a decorative unit having a plurality of protrusions provided in a region defined by a plurality of first trenches and a plurality of second trenches.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a dial decorating method, a dial, and a timepiece equipped with said dial. [Background technology]

[0002] There is a known technology for decorating watch parts such as dials by laser processing. For example, Patent Document 1 discloses a decoration method that uses laser processing to create multiple grooves in watch parts, making it possible to express a variety of brightness levels. In more detail, by creating areas with shallow grooves and areas with deep grooves, the degree of light reflection is changed, making it possible to express a variety of brightness levels.

[0003] For example, FIG. 17 of the document shows the change in lightness when a plurality of grooves are formed in a grid pattern on a base material made of nickel silver and the depth of the grooves is changed. From FIG. 17, the lightness L * The brightness is about 13. * When the value is 13, the decorative portion is black, which has a high contrast with the silver-white nickel silver and can be clearly observed. Therefore, it is considered suitable for application to, for example, the hour scale of a dial. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2022-11407 Summary of the Invention [Problem to be solved by the invention]

[0005] However, there is room for improvement in the decoration method of Patent Document 1. For example, when a white dial is provided with a grid-like decorated hour scale, the black hour scale can be clearly observed on a white background, but there is an issue that it lacks a three-dimensional effect. This is because the hour scale is decorated flush with the surface of the dial. In order to achieve a three-dimensional effect, it is possible to set abbreviated characters as hour markers on the dial, but in that case, it is necessary to place the hands on top of the abbreviated characters, making it difficult to make the watch thin. In other words, there was a demand for a decoration method that was thin and had a three-dimensional feel. [Means for solving the problem]

[0006] A dial decorating method according to one embodiment of the present application includes a first step of forming a recess by irradiating a first laser, and a second step of forming a groove in at least a portion of the recess by irradiating a second laser.

[0007] The dial of one embodiment of the present application comprises a recess formed by laser irradiation, and a decorative portion formed on a bottom surface of the recess by laser irradiation, the decorative portion including a first groove extending in a first direction and a second groove extending in a second direction intersecting the first direction, and having a plurality of protrusions provided in an area partitioned by a plurality of the first grooves and a plurality of the second grooves.

[0008] A timepiece according to one aspect of the present application comprises the above-mentioned dial and hands including hour and minute hands. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a front view of the timepiece according to the first embodiment. [Diagram 2] FIG. 2 is a cross-sectional view taken along line bb in FIG. 1 . [Diagram 3] FIG. [Figure 4] FIG. 4 is a flowchart showing the flow of a method for decorating the hour scale. [Diagram 5] FIG. 1 is a schematic diagram of a laser processing device. [Figure 6] Enlarged view of part c in Figure 2. [Figure 7] FIG. 4 is a graph showing the correlation between the depth of the first groove and the brightness. [Figure 8] A close-up photo of the decorated hour scale. [Figure 9]FIG. 11 is a plan view of the hour scale according to the second embodiment. [Figure 10] FIG. 11 is a cross-sectional view of an hour scale according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] EMBODIMENT 1 ***Clock Overview*** FIG. 1 is a front view of the watch. Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0011] The timepiece 100 of this embodiment is a three-hand analog wristwatch. The timepiece 100 is composed of a case 30, a dial 5, a second hand 1, a minute hand 2, an hour hand 3, a crown 40, etc. Body 30 is a case, and is made of hard metal such as stainless steel, titanium, etc. The back of dial 5 in body 30 houses a movement (not shown) for driving the hands.

[0012] The dial 5 is provided with a logo 8, hour scale 10, minute scale 11, etc. A through hole (not shown) for passing the axis of the hands is formed in the center of the circular dial 5, and a second hand 1, minute hand 2, and hour hand 3 are attached to it. The logo 8 is a logo representing the brand name or product name of the watch 100. The 10 hour markers are marked with Roman numerals, with corresponding Roman numerals located between 1 o'clock and 12 o'clock.

[0013] The minute scale 11 is provided as a part of the railway 15. The railway 15 is configured with the minute scale 11, which corresponds to a sleeper, arranged on two rail-shaped annular parts consisting of an inner circumference circle 13 and an outer circumference circle 14. The minute scale 11 is arranged like a bar at positions corresponding to 1 minute to 60 minutes on the annular parts. The annular parts consisting of the inner circumference circle 13 and the outer circumference circle 14 are an example of a pattern. The minute scale 11 also serves as a second scale. The minute scale 11 and the hour scale 10 are collectively referred to as scales. The crown 40 is a crown head, and is provided so that the time can be adjusted by pulling it out one step. Note that the crown 40 may have other functions.

[0014] In a preferred embodiment, the dial 5 is made of nickel silver, and its surface is silver-white with metallic luster. The hour scale 10 has black minute gradations formed by applying a decorative process to a part of the dial 5 using laser irradiation, which will be described later. In particular, the black portion is engraved, so that the black hour scale 10 can be observed three-dimensionally against the silver-white base.

[0015] ***Hour scale configuration*** Fig. 2 is a cross-sectional view taken along the line bb in Fig. 1, showing a cross section of the hour scale 10 at 1 o'clock. Fig. 3 is a perspective view of the decorative portion. Each figure shows three mutually orthogonal axes, the X-axis, the Y-axis, and the Z-axis. The plane including the X-axis and the Y-axis is a plane along the surface 5b of the dial 5, and the Z-positive direction indicates the thickness direction of the dial 5. As shown in FIG. 2, the hour scale 10 is composed of a recess 12 that is dug from the surface 5b of the dial 5 along the shape of the hour scale 10, and a decorative portion 17 that includes a plurality of protrusions 19 that are formed by dug from the bottom surface 12a of the recess 12.

[0016] The recess 12 is a portion that is dug down from the surface 5b of the dial 5 along the shape of the hour scale 10, and in Fig. 2, it is dug down from the surface 5b by a dimension d1. By providing this recess 12, the hour scale 10 has a three-dimensional configuration. In other words, the recess 12 is a depression with a substantially flat bottom surface 12a. The decorative portion 17 is formed on the bottom surface 12a of the recess 12 and includes a first groove 18a extending in the Y-positive direction as a first direction, and a second groove 18b (FIG. 3) extending in the X-positive direction as a second direction intersecting with the Y-positive direction. The decorative portion 17 has a plurality of protrusions 19 provided in an area defined by the first grooves 18a and the second grooves 18b. The first grooves 18a and the second grooves 18b are dug down by a dimension d2 from the bottom surface 12a. In other words, the height of the protrusions 19 is the dimension d2. In this embodiment, the first grooves 18a and the second grooves 18b are formed on the entire bottom surface 12a of the recess 12.

[0017] In addition, the arrangement pitch p of adjacent first grooves 18a is approximately 0.035 mm in a preferred embodiment. However, this is not limited to this, and the arrangement pitch p may be 0.025 mm or more and 0.075 mm or less. The arrangement pitch of second grooves 18b (FIG. 3) is the same as the arrangement pitch p of first grooves 18a. 3, the protrusions 19 are cone-shaped as a whole, with a small hemispherical tip, and are formed in each area partitioned by the first groove 18a and the second groove 18b. In other words, a plurality of protrusions 19 are carved out by the two intersecting first grooves 18a and second grooves 18b. The first grooves 18a and the second grooves 18b are formed by multiple laser irradiations.

[0018] ***How ​​the hour scale is manufactured*** Fig. 4 is a flow chart showing the flow of the method for decorating the hour scale, and Fig. 5 is a schematic diagram of a laser processing device. Next, a method for decorating the hour scale 10 will be described with reference mainly to FIG.

[0019] In step S10, the base material 5a of the dial 5 is set in the laser processing device 50. More specifically, the operator sets the base material 5a to be processed on the processing table 45 of the laser processing device 50 shown in FIG. 5. The operator starts a decoration program in the control device 47 of the laser processing device 50 in parallel with setting the base material 5a. The base material 5a is, for example, a plate material made of nickel silver with a thickness of about 0.3 mm. Note that the material is not limited to this, and any metal may be used, for example, brass, precious metals such as gold, silver, platinum, copper, stainless steel, etc., or an alloy of these may be used.

[0020] Since the laser processing device 50 is the main operator in the steps S11 and after, the schematic configuration of the laser processing device 50 will be described first with reference to FIG. The laser processing device 50 comprises a laser oscillator 41, a transmission optical system 42, an irradiation unit 43, a processing table 45, a control device 47, and the like. A YAG (Yttrium Aluminum Garnet) laser is used as a suitable example of the laser oscillator 41. Note that any device capable of similar laser irradiation may be used, for example, a CO2 laser or a fiber laser. The transmission optical system 42 is an optical path that transmits the laser light generated by the laser oscillator 41 to the irradiation unit 43, and is configured to include a plurality of reflecting mirrors.

[0021] The irradiation unit 43 is an irradiation nozzle that focuses laser light and irradiates the workpiece, and includes a focusing lens. The processing table 45 is an XY table, and in accordance with instructions from a control device 47, moves a placed object to be processed in a plane in accordance with the scanning path pattern of laser irradiation. The control device 47 is a controller for the laser processing device 50, and is configured to include one or more processors, and controls the operation of each part. The control device 47 is equipped with a storage unit 48 including a non-volatile memory. The storage unit 48 stores a control program for controlling the operation of the laser processing device 50, a decoration program described below, various data, and the like. The decoration program specifies the order and contents for forming the recesses 12 and grooves, and the various data stores irradiation conditions and scanning path pattern data. The irradiation conditions include parameters such as output frequency, scanning speed, laser output, and scanning path pitch.

[0022] Return to Figure 4. In step S11, the recesses 12 are formed according to the decoration program. More specifically, as shown in FIG. 2, a laser is irradiated multiple times from the surface 5b of the base material 5a along the shape of the hour scale 10 to form the recesses 12 dug down to a dimension d1. In a preferred embodiment, the shape of the hour scale 10 is repeatedly scanned and irradiated with femtosecond pulsed laser to dug down to the dimension d1. In order to increase the processing efficiency, picosecond or nanosecond pulsed laser irradiation may be used, but it is preferable to use femtosecond pulsed laser irradiation for parts requiring high processing accuracy such as contour parts. The depth (dimension d1) of the recesses 12 is, for example, 50 μm. In addition, it is not limited to this, and may be set according to the desired three-dimensional effect, and is preferably 50 μm or more and 200 μm or less. In addition, step S11 corresponds to the first step, and the laser irradiation when forming the recesses 12 corresponds to the first laser irradiation.

[0023] In steps S12 and S13, laser irradiation for forming the first groove 18a and laser irradiation for forming the second groove 18b are repeated according to the decoration program. For example, as shown in FIG. 3, laser irradiation is started from a starting point 31, and when the irradiation of the first groove 18a is completed, the adjacent first groove 18a is irradiated as shown by the arrow, and when the irradiation of the first groove 18a is completed, the adjacent first groove 18a is irradiated as shown by the arrow, and so on, all of the first grooves 18a are irradiated in a zigzag manner in a single stroke. Next, laser irradiation is started from a starting point 32, and when the irradiation of the second groove 18b is completed, the adjacent second groove 18b is irradiated as shown by the arrow, and so on, all of the second grooves 18b are irradiated in a single stroke. Then, this series of single-stroke irradiation is repeated a set number of times. In this way, by performing irradiation in a single stroke, unnecessary movements are reduced and production efficiency can be improved.

[0024] Steps S12 and S13 correspond to the second step, and the laser irradiation for forming the first groove 18a and the second groove 18b corresponds to the second laser irradiation. In a preferred embodiment, the second laser irradiation is performed by femtosecond pulse laser irradiation. In other words, the decoration method includes a first step of forming the recess 12 by irradiating the first laser, and a second step of forming a groove in at least a part of the recess 12 by irradiating the second laser. The irradiation conditions are set appropriately depending on the material of the dial 5 and the depth of the groove, but for example, the conditions described in Patent Document 1 may be used.

[0025] Fig. 6 is an enlarged view of part c in Fig. 2. Fig. 7 is a graph showing the correlation between the depth of the first groove and the brightness. 6 is an enlarged cross-sectional view of the first groove 18a, and shows the tracks made by multiple laser irradiations in the shape of tree rings. In detail, the track of the groove made by the first laser irradiation is shown as track 22a, the track made by the second laser irradiation is shown as track 22b, and similarly, the track made by the third laser irradiation is shown as track 22c, the track made by the fourth laser irradiation is shown as track 22d, and so on, in multiple stages.

[0026] 6, the first groove 18a is gentle near the opening and becomes steeper as it gets deeper. Therefore, the angle 26 between the tangent line along the slope of the first-stage locus 22a and the center line 36 of the first groove 18a is larger than the angle 27 between the tangent line along the slope of the sixth-stage locus 22f and the center line 36 of the first groove 18a. The same is true for the second groove 18b. Here, most of the light incident on the first groove 18a is absorbed in the first groove 18a due to attenuation caused by repeated reflection between the side walls of the first groove 18a and absorption by the side walls. As a result, the deeper the first groove 18a, the darker the groove becomes, and therefore the darker the entire decorative part 17 having multiple grooves becomes. In other words, the higher the protrusion 19, the darker the entire decorative part 17 becomes.

[0027] Graph 33 shown in FIG. 7 shows the correlation between the depth and brightness of the first grooves 18a. The horizontal axis represents the groove depth in μm, and the vertical axis represents the brightness L * The depth of the groove corresponds to dimension d2 (Fig. 2). Here, the target brightness L at the hour scale 10 on the dial 5 * This is an indication for obtaining clear black hour scale 10 on silver-white dial 5. As shown in graph 33, the brightness decreases as the groove depth increases, and when the depth is 100 μm, the target brightness L * It can be seen that the depth approaches 13. Although it depends on the material and design of the dial 5, it is preferable that the depth (dimension d2) of the first groove 18a and the second groove 18b is 25 μm or more and 150 μm or less. Furthermore, if it is desired to make the contrast with the dial 5 clearer, it is preferable that the depth (dimension d2) of the first groove 18a and the second groove 18b is 100 μm or more and 150 μm or less.

[0028] Return to Figure 4. In step S14, since a series of processes according to the decoration program has been completed, the laser irradiation is terminated.

[0029] ***Actual appearance of hour scale*** FIG. 8 is an enlarged photograph of the decorated hour scale. 8 is an enlarged photograph of the 9 o'clock scale processed by the above-mentioned decoration method. The depth (dimension d1) of the recess 12 is 50 μm, and the depth (dimension d2) of the first groove 18a and the second groove 18b is 100 μm. As shown in FIG. 8, the hour scale 10 can be observed three-dimensionally from the surface 5b of the dial 5. Although it is difficult to tell because it is a photograph taken from the front, the hour scale 10 appears particularly three-dimensional at its upper part. The sense of three-dimensionality can be further enhanced by increasing the depth of the recess 12. It can also be seen that the black hour scale 10 has a high contrast against the silver-white base of the dial 5 and can be observed clearly.

[0030] As described above, the decoration method, dial 5, and timepiece 100 of this embodiment provide the following advantages. The decoration method of this embodiment includes step S11 as a first process of forming a recess 12 by irradiating a first laser, and steps S12 and S13 as a second process of forming a groove in at least a part of the recess 12 by irradiating a second laser.

[0031] This makes it possible to realize the hour scale 10 in which the decorative portion 17 is provided on the bottom surface 12a that is dug down one step from the surface 5b of the dial 5 by the recess 12. Therefore, unlike the conventional hour scale in which the decorative portion is provided flush with the surface 5b of the dial 5, the hour scale 10 of this embodiment makes it possible to configure a three-dimensional hour scale 10. Furthermore, since there is no need to inscribe abbreviated characters on the dial 5, the hands can be placed directly above the dial 5, allowing the timepiece 100 to be made thinner. Therefore, it is possible to provide a method for decorating a thin dial 5 having a three-dimensional effect.

[0032] Moreover, the recess 12 is preferably a depression having a substantially flat bottom surface 12a. According to this, the decorative portion 17 can be provided at a position recessed from the surface 5b of the dial 5, so that the hour scale 10 can be configured three-dimensionally.

[0033] Further, the grooves of the decorative portion 17 include a first groove 18a extending in a first direction and a second groove 18b extending in a second direction intersecting the first direction, and a protrusion portion 19 is formed in the area partitioned by the multiple first grooves 18a and the multiple second grooves 18b. According to this, by adjusting the depth of the first grooves 18a and the second grooves 18b, it is possible to form the decorative portion 17 having a desired brightness.

[0034] Further, the plurality of first grooves 18a and the plurality of second grooves 18b are formed on the entire bottom surface 12a of the recess 12. According to this, when applied to the hour scale 10, for example, the entire hour scale can have a uniform texture with the brightness of the decorative portion 17.

[0035] The depth of the recess 12 is not less than 50 μm and not more than 200 μm, and the depth of the first groove 18a and the second groove 18b from the bottom surface 12a of the recess 12 is not less than 25 μm and not more than 150 μm. According to this, the decorative portion 17 is provided in a portion that is dug down one step from the surface 5b of the dial 5 by the recess 12, so that it is possible to form the hour scale 10 with a three-dimensional effect.

[0036] Moreover, the depth of the first groove 18a and the second groove 18b from the bottom surface 12a of the recess 12 is preferably not less than 100 μm and not more than 150 μm. According to this, the brightness of the decorative portion 17 is reduced, so that the contrast with the dial 5 is increased, and the hour markers 10 can be made clearer.

[0037] Moreover, the first laser irradiation and the second laser irradiation are preferably femtosecond laser irradiation. This allows for highly accurate machining of the contour of the hour scale 10, the first groove 18a, the second groove 18b, and other fine details that require precision.

[0038] The dial 5 includes a recess 12 formed by laser irradiation, and a first groove 18a formed on a bottom surface 12a of the recess 12 by laser irradiation, the first groove 18a extending in a first direction, and a second groove 18b extending in a second direction intersecting the first direction, and is equipped with a plurality of protrusions 19 provided in an area partitioned by the plurality of first grooves 18a and the plurality of second grooves 18b. This makes it possible to provide a dial 5 equipped with hour scales 10 that are decorated with a three-dimensional effect.

[0039] The timepiece 100 has a dial 5 and hands including an hour hand 3 and a minute hand 2 . This makes it possible to provide a slim timepiece 100 equipped with a dial 5 that has a three-dimensional scale.

[0040] EMBODIMENT 2 ***Different configurations of hour scales-1*** FIG. 9 is a plan view of the hour scale according to the second embodiment, and corresponds to FIG. In the above embodiment, the decorative portion 17 is described as being provided on the entire bottom surface 12a of the recess 12, but this is not limiting, and the decorative portion 17 may be provided on only a portion of the bottom surface 12a. For example, the hour scale 70 of this embodiment has a portion that does not have the decorative portion 17. Hereinafter, the same parts as those in the above embodiment are given the same numbers, and duplicated explanations will be omitted.

[0041] The hour scale 70 shown in Fig. 9 is a 5 o'clock scale, but the bottom surface 12a is exposed on the inside of the left line. In other words, the left line has a decorative portion 17 on the outline, but the bottom surface 12a is left as is on the inside. The right line has a decorative portion 17 on the entire surface. In this case, the scale 70 allows accents to be added to the design without compromising the three-dimensional effect.

[0042] Return to Figure 1. In the above, it has been described that the recesses 12 and the decorative portions 17 are provided on the hour scale 10, but this is not limited to this, and both may be provided on the scale, pattern, or logo provided on the dial 5. For example, the recess 12 and the decorative portion 17 may be provided on the logo 8, the minute scale 11, and the railway 15 in the dial 5 in Fig. 1. The decorative portion 17 is not limited to being provided on the entire surface of the recess 12, and may be provided on a part of the recess 12. In other words, the recess 12 and the decorative portion 17 are provided on the portion of the scale, pattern, or logo.

[0043] As described above, the decoration method and watch 100 of this embodiment can provide the following effects in addition to the effects of the above embodiment. In the hour scale 70, the decorative portion 17 is provided on a part of the bottom surface 12a, and the bottom surface 12a remains in the portion without the decorative portion 17. This makes it possible to provide the hour scale 70 that accentuates the design without impairing the three-dimensional effect.

[0044] Moreover, the recesses 12 and the decorative portions 17 are provided in the areas of the scales, patterns, or logos. This allows three-dimensional and clear scales, patterns, and logos to be provided on the dial 5. In addition, by changing the depth of the recesses 12 in each area and the depth of the decorative parts 17, the three-dimensional effect and brightness can be individually adjusted, making it possible to realize a variety of designs and improving the design of the dial 5.

[0045] EMBODIMENT 3 ***Different configurations of hour scales-2*** FIG. 10 is a cross-sectional view of the hour scale according to the third embodiment, and corresponds to FIG.

[0046] As shown in Fig. 10, a clear layer 38 may be provided on the surface of the hour scale 10. Hereinafter, the same parts as those in the above embodiment are given the same numbers, and duplicated explanations will be omitted. In the hour scale 10 of this embodiment, a clear layer 38 is provided on the decorative portion 17. The other configurations are the same as those described in FIG. In a preferred embodiment, the clear layer 38 is made of an acrylic resin, which is applied onto the decorative portion 17 using a precision dispenser. The process of forming the clear layer 38 corresponds to the third process. The clear layer 38 may be made of any resin material having transparency, such as a cellulose resin, a polyurethane resin, or an acrylic lacquer resin.

[0047] As described above, the decoration method and watch 100 of this embodiment can provide the following effects in addition to the effects of the above embodiment. The decorating method of the present embodiment further includes a third step of forming a clear layer 38 that covers the first grooves 18a, the second grooves 18b and the protrusions 19. This can further enhance the three-dimensional effect of the hour scale 10. Furthermore, adhesion of dust to the hour scale 10 can be prevented. [Explanation of symbols]

[0048] 1...second hand, 2...minute hand, 3...hour hand, 5...dial, 5a...base material, 5b...surface, 8...logo, 10...hour scale, 11...minute scale, 12...recess, 12a...bottom, 13...inner circumference, 14...outer circumference, 15...railway, 17...decoration, 18a...first groove, 18b...second groove, 19...projection, 22a-22f...trajectory, 26...angle, 27...angle, 30...body, 31...starting point, 32...starting point, 33...graph, 36...center line, 38...clear layer, 40...crown, 41...laser oscillator, 42...transmission optical system, 43...irradiation unit, 45...processing table, 47...control device, 48...memory unit, 50...laser processing device, 70...hour scale, 100...clock, d1...dimension, d2...dimension.

Claims

1. a first step of forming a recess by irradiating a first laser; a second step of forming a groove in at least a part of the recess by irradiating a second laser; A method for decorating a dial, comprising:

2. The recess is a depression having a substantially flat bottom surface. The method for decorating a dial according to claim 1.

3. The groove is A first groove extending in a first direction; a second groove extending in a second direction intersecting the first direction, A protrusion is formed in an area defined by the plurality of first grooves and the plurality of second grooves. The method for decorating a dial according to claim 2.

4. The plurality of first grooves and the plurality of second grooves are formed on the entire bottom surface of the recessed portion, The method for decorating a dial according to claim 3.

5. The depth of the recess is 50 μm or more and 200 μm or less, a depth of the first groove and the second groove from the bottom surface of the recess is 25 μm or more and 150 μm or less; The method for decorating a dial according to claim 3 or 4.

6. The depth of the first groove and the second groove from the bottom surface of the recess is 100 μm or more and 150 μm or less. The method for decorating a dial according to claim 5.

7. The method further includes a third step of forming a clear layer covering the first groove, the second groove, and the protrusion. The method for decorating a dial according to claim 3 or 4.

8. The first laser irradiation and the second laser irradiation are femtosecond laser irradiations; The method for decorating a dial according to claim 3 or 4.

9. A recess formed by laser irradiation; a first groove formed on a bottom surface of the recess by laser irradiation and extending in a first direction; and a second groove extending in a second direction intersecting the first direction; a decorative portion having a plurality of protrusions provided in an area defined by the plurality of first grooves and the plurality of second grooves; Dial.

10. The recess and the decorative portion are provided in a portion of a scale, a pattern, or a logo.

10. The dial according to claim 9.

11. A dial according to claim 9 or 10; and hands including hour and minute hands. clock.

Images