Patent Description:
The present disclosure relates to a timepiece component, a timepiece, and a method for manufacturing a timepiece component.

A timepiece component is used in which figures such as characters and marks are formed by irradiating a metal surface with a laser. In <CIT>, a femtosecond laser is used as the laser. Abrasion processing is performed to instantaneously vaporize and disperse a solid at a metal surface by irradiating a timepiece component with a femtosecond laser. By the abrasion processing, a surface having a large surface roughness and a low glossiness is formed. A groove having a low glossiness at the bottom is formed at a position irradiated with the femtosecond laser. Patterns such as figures, characters, and marks are formed in the timepiece component by the groove.

Since a femtosecond laser is used in processing disclosed in <CIT>, a surface having a low glossiness at a bottom of a groove is formed on a timepiece component. In processing of a timepiece component, it may be desired to impart gloss to a fine cutting surface formed by femtosecond laser processing. In such a case, it is necessary to provide another process different from the femtosecond laser processing. However, it is difficult to execute gloss processing on a fine cutting surface formed by a femtosecond laser, and productivity may also be reduced when another process is provided. Therefore, a manufacturing method has been desired by which an aesthetic appearance is attained by imparting gloss to any portion of a surface to be processed by a femtosecond laser.

<CIT> discloses a method of manufacturing a watch component comprising a surface to be treated, this surface being prepared beforehand by a sub-step of polishing and/or by a sub-step of adding an upper malleable layer (<NUM>), comprising surface structuring of said surface to be treated of the watch component, then second surface structuring of said surface to be treated structured by the previous step of first surface structuring.

<CIT> discloses a decorating method for decorating a metal component by laser irradiation. The method includes performing laser irradiation while scanning, with a first element as a starting point, along a direction toward the metal component, and an oxide film is formed on the front surface of the metal component by the laser irradiation. Furthermore, <CIT> discloses a method of manufacturing a watch component comprising a surface to be treated, said surface to be treated having a first processed surface having a predetermined pattern with a first laser formed during a first step, and having a second surface roughness smaller than that of the first processed surface in a second step, said first and second surfaces being at least partially superimposed.

A method for manufacturing a timepiece component includes: forming a first processed surface having a predetermined pattern by irradiating a surface of a metal component with a first laser having a pulse width of femtoseconds; and forming a second processed surface having a surface roughness smaller than that of the first processed surface by irradiating at least a part of the first processed surface with a second laser having a pulse width of femtoseconds or more, wherein when forming the first processed surface, an oxide film is formed on the first processed surface, and when forming the second processed surface, an oxide film thicker than the oxide film of the first processed surface is formed on the second processed surface.

A timepiece component includes: a base material made of metal; a first processed surface that has a predetermined pattern, that has a surface roughness of a first surface roughness, and that is formed by irradiating the base material with the first laser having a pulse width of femtoseconds; and a second processed surface that has a surface roughness of a second surface roughness smaller than the first surface roughness, and that is formed by irradiating at least a part of the first processed surface with the second laser having a pulse width of femtoseconds or more, wherein the first processed surface and the second processed surface have an oxide film on a surface thereof, and the oxide film on the surface of the second processed surface is thicker than the oxide film on the surface of the first processed surface.

A timepiece includes the above-described timepiece component.

In <FIG>, a timepiece <NUM> according to the present embodiment is a three-pointer analog wristwatch. <FIG> is a view of the timepiece <NUM> as viewed from the back side. The timepiece <NUM> is not limited to an analog timepiece. Alternatively, the timepiece <NUM> may be a timepiece provided with a metal component, and may be, for example, a digital timepiece, a combination timepiece, a smart watch, or a health watch.

The timepiece <NUM> is a wristwatch having a see-through back. Since a transparent back cover <NUM> is attached to a body <NUM>, an internal mechanism can be observed. The body <NUM> functions as a case. A material of the body <NUM> is a hard metal such as titanium or stainless steel. The body <NUM> has a substantially circular shape. The back cover <NUM> is fitted to the inner periphery of a ring-shaped wall of the body <NUM>. A material of the back cover <NUM> is sapphire glass.

A movement <NUM> for driving pointers is housed inside the body <NUM>. In <FIG>, a receiving plate <NUM> serving as a timepiece component and a metal component of the movement <NUM> is observed through the back cover <NUM>. The receiving plate <NUM> includes a base material <NUM> made of metal. The base material <NUM> is provided with a plurality of gear bearings <NUM>. A material of the base material <NUM> is titanium, a titanium alloy, or stainless steel. Alternatively, as the material of the base material <NUM>, a metal such as nickel silver, brass, duralumin, or an alloy containing iron may be used.

The base material <NUM> includes a first region <NUM>, a second region <NUM>, and a third region <NUM>. A surface of the base material <NUM> in the first region <NUM> is a first processed surface <NUM>. Shapes of the first region <NUM> and the first processed surface <NUM> form a first pattern <NUM> serving as a pattern. In other words, the first processed surface <NUM> has the first pattern <NUM>. A surface roughness of the first processed surface <NUM> is a first surface roughness. The first processed surface <NUM> and the first pattern <NUM> are formed by irradiating the base material <NUM> with a first laser having a pulse width of femtoseconds. The first laser is, for example, a femtosecond laser, and a range of the pulse width is preferably <NUM> fs to <NUM> fs.

A surface of the base material <NUM> in the second region <NUM> is a second processed surface <NUM>. The second processed surface <NUM> in the second region <NUM> includes four portions. Shapes of the four portions are a second pattern <NUM> serving as a pattern, a third pattern <NUM> serving as a pattern, a fourth pattern <NUM> serving as a pattern, and a fifth pattern <NUM> serving as a pattern. A surface roughness of the second processed surface <NUM> is a second surface roughness. The second surface roughness is smaller than the first surface roughness. The second processed surface <NUM> is formed by irradiating the first processed surface <NUM> with a second laser having a pulse width of femtoseconds or more. Therefore, the second processed surface <NUM> is a surface covering a part of the first processed surface <NUM>. According to the present embodiment, the first processed surface <NUM> has the first pattern <NUM> and the second pattern <NUM> to the fifth pattern <NUM>. The second processed surface <NUM> has the second pattern <NUM> to the fifth pattern <NUM>.

The surface roughness of the first processed surface <NUM> is the first surface roughness. The surface roughness of the second processed surface <NUM> is the second surface roughness. A surface roughness is based on a surface shape of a surface to be measured. The surface roughness is an arithmetic average roughness Sa. The first surface roughness and the second surface roughness are measured by a shape analysis laser microscope. The shape analysis laser microscope is a VK-X250 (registered trademark) manufactured by Keyence Corporation. A magnification of the shape analysis laser microscope at the time of measurement is <NUM> times.

A surface of the base material <NUM> in the third region <NUM> is a non-processed surface <NUM>. The non-processed surface <NUM> in the third region <NUM> includes four portions. Shapes of the four portions are a sixth pattern <NUM>, a seventh pattern <NUM>, an eighth pattern <NUM>, and a ninth pattern <NUM>. The non-processed surface <NUM> is a surface that is neither irradiated with the femtosecond laser nor irradiated with the second laser.

<FIG> are examples of roughness curves in line roughness measurement in which a surface roughness is measured along a predetermined line. A horizontal axis represents a measurement position at which the surface roughness is measured. Specifically, the measurement position is represented by a distance from a measurement start point. A vertical axis represents a position of a surface shape in a thickness direction of the base material <NUM>. An average position of the measurement results is <NUM>. A + direction is a direction in which the surface shape protrudes, and a - direction is a direction in which the surface shape is recessed.

As illustrated in <FIG>, in an example of a surface shape of the first processed surface <NUM>, unevenness of the surface changes between -<NUM> to +<NUM>.

As illustrated in <FIG>, in an example of a surface shape of the second processed surface <NUM>, unevenness of the surface changes between -<NUM> to +<NUM>. The second processed surface <NUM> has a surface roughness smaller than that of the first processed surface <NUM>.

The surface roughness is obtained by a surface roughness measurement, which is a measurement attained by two-dimensionally expanding the line roughness measurement. Similar to the line roughness measurement, in the surface roughness measurement, the surface roughness of the second processed surface <NUM> is also smaller than that of the first processed surface <NUM>. Therefore, the second surface roughness is smaller than the first surface roughness. The second surface roughness is preferably <NUM> or more and <NUM> or less.

According to this configuration, the surface of the base material <NUM> includes the first processed surface <NUM> and the second processed surface <NUM>. Since the first processed surface <NUM> has a surface roughness larger than that of the second processed surface <NUM>, the first processed surface <NUM> is a so-called matte surface having a low glossiness. The glossiness is measured by a gloss meter. Since the second processed surface <NUM> has a surface roughness smaller than that of the first processed surface <NUM>, the second processed surface <NUM> is a surface having a high glossiness. Since the surface of the base material <NUM> includes the first processed surface <NUM> having a low glossiness and the second processed surface <NUM> having a high glossiness, the surface of the base material <NUM> can have an aesthetic appearance as compared with a case in which the surface of the base material <NUM> only includes the first processed surface <NUM> having a low glossiness.

Next, a method for manufacturing the first processed surface <NUM> and the second processed surface <NUM> of the receiving plate <NUM> described above will be described. In the flowchart in <FIG>, step S1 is a first machining process. In this process, the surface of the base material <NUM> of the receiving plate <NUM> is irradiated with a femtosecond laser, thereby forming the first processed surface <NUM> having the first pattern <NUM> and the second pattern <NUM> to the fifth pattern <NUM>. Next, the process proceeds to step S2.

Step S2 is a second machining process. In this process, a part of the first processed surface <NUM> is irradiated with the second laser having a pulse width of femtoseconds or more, thereby forming the second processed surface <NUM> having a surface roughness smaller than that of the first processed surface <NUM> and having an oxide film thicker than that of the first processed surface <NUM>. Through processes described above, the first processed surface <NUM> and the second processed surface <NUM> are completed. Here, the pulse width of femtoseconds or more is, for example, preferably <NUM> fs or more, and more preferably <NUM> ns or more and <NUM> ns or less.

Next, a manufacturing method will be described in detail corresponding to the steps illustrated in <FIG>.

<FIG> are views corresponding to the first machining process of step S1. As illustrated in <FIG>, a laser machining apparatus <NUM> is prepared. The laser machining apparatus <NUM> includes a first laser light source <NUM> and a second laser light source <NUM>. The first laser light source <NUM> is a light source that emits a femtosecond laser <NUM>. The second laser light source <NUM> is a light source that emits a nanosecond laser. The second laser light source <NUM> may emit a laser having a pulse width of femtoseconds or more. A laser emitted by the second laser light source <NUM> is not limited to the nanosecond laser. The second laser light source <NUM> is also used as a light source that emits a picosecond laser.

The laser machining apparatus <NUM> includes an irradiation unit <NUM> that irradiates the base material <NUM> with the femtosecond laser <NUM> or the nanosecond laser. The first laser light source <NUM> and the irradiation unit <NUM> are coupled by a first optical fiber <NUM>. The femtosecond laser <NUM> emitted from the first laser light source <NUM> is supplied to the irradiation unit <NUM> through the first optical fiber <NUM>. The second laser light source <NUM> and the irradiation unit <NUM> are coupled by a second optical fiber <NUM>. The nanosecond laser emitted from the second laser light source <NUM> is supplied to the irradiation unit <NUM> through the second optical fiber <NUM>.

The irradiation unit <NUM> includes a condenser lens 29a and a shutter 29b. The condenser lens 29a condenses the femtosecond laser <NUM> and the nanosecond laser on the surface of the base material <NUM>. The diameter of a first light condensing unit 28a on which the femtosecond laser <NUM> and the nanosecond laser are condensed is not limited, and for example, is <NUM> in the present embodiment. The shutter 29b switches between irradiation and non-irradiation with the femtosecond laser <NUM> and the nanosecond laser.

The laser machining apparatus <NUM> includes an X table <NUM> that moves the irradiation unit <NUM> in an X direction. The laser machining apparatus <NUM> includes a Y table <NUM> that moves the base material <NUM> in a Y direction. The X table <NUM> and the Y table <NUM> include a servomotor (not illustrated).

The laser machining apparatus <NUM> includes a control device <NUM>. The control device <NUM> controls a moving speed and a moving amount of the X table <NUM> and the Y table <NUM>. The control device <NUM> includes a storage unit <NUM>. The storage unit <NUM> stores coordinate data of a path for irradiating the base material <NUM> with the femtosecond laser <NUM>. The control device <NUM> can perform scanning with the femtosecond laser <NUM> or the nanosecond laser within a predetermined pattern based on the coordinate data of the path.

The control device <NUM> is electrically coupled to the first laser light source <NUM>, the second laser light source <NUM>, and the irradiation unit <NUM>. The control device <NUM> controls start and stop of light emission of the first laser light source <NUM> and the second laser light source <NUM>. The control device <NUM> controls opening and closing of the shutter 29b of the irradiation unit <NUM>.

In step S1, the first laser light source <NUM> emits the femtosecond laser <NUM>, and the second laser light source <NUM> stops emitting light. The base material <NUM> is irradiated with the femtosecond laser <NUM>. Unevenness <NUM> is formed on the surface of the base material <NUM> along a trajectory for irradiation with the femtosecond laser <NUM>. Abrasion processing is performed to instantaneously vaporize and disperse metal molecules at the surface of the base material <NUM> by performing irradiation with the femtosecond laser <NUM>. By the abrasion processing, a surface having a large surface roughness and a low glossiness is formed.

As illustrated in <FIG>, a plurality of first trajectories <NUM>, which are trajectories for irradiation with the femtosecond laser <NUM>, are arranged in parallel. The first trajectories <NUM> may be curved lines or straight lines. The first trajectories <NUM> may be a figure of a combination of curve lines and straight lines. As a result, the unevenness <NUM> is provided in a predetermined pattern without gaps.

Conditions for irradiation with the femtosecond laser <NUM> are not particularly limited. According to the present embodiment, for example, a laser fluence of the first light condensing unit 28a of the femtosecond laser <NUM> is <NUM> mJ/cm<NUM> to <NUM> mJ/cm<NUM>. A frequency of a laser pulse is about <NUM>. A scanning speed is <NUM>/s. A pitch of a position irradiated with the laser pulse is <NUM>.

As illustrated in <FIG>, the first processed surface <NUM> having the first pattern <NUM>, the second pattern <NUM>, the third pattern <NUM>, the fourth pattern <NUM>, and the fifth pattern <NUM> is formed on the base material <NUM> of the receiving plate <NUM>.

<FIG> are views corresponding to the second machining process of step S2. As illustrated in <FIG>, a laser machining apparatus <NUM> is used. In step S2, the first laser light source <NUM> stops emitting light, and the second laser light source <NUM> emits a nanosecond laser <NUM> serving as the second laser. The base material <NUM> is irradiated with the nanosecond laser <NUM>. A diameter of a second light condensing unit 39a on which the nanosecond laser <NUM> is condensed is <NUM>. A laser fluence of the second light condensing unit 39a of the nanosecond laser <NUM> is <NUM> mJ/cm<NUM> to <NUM> mJ/cm<NUM>. A frequency of the laser pulse is about <NUM>. A scanning speed is <NUM>/s. A pitch of a position irradiated with the laser pulse is <NUM>. A pitch of a position irradiated with the laser pulse is not particularly limited, and when the diameter of the second light condensing unit 39a is <NUM>, the pitch is preferably <NUM> or more and <NUM> or less. A value obtained by dividing the pitch by the diameter of the second light condensing unit 39a is preferably <NUM> or more and <NUM> or less. When the pitch is less than <NUM>, productivity is low. When the pitch exceeds <NUM>, uniformity of the appearance is impaired. By performing irradiation with the nanosecond laser <NUM> at regular intervals with a constant pitch, a film thickness of an oxide film can be close to a constant value.

When the second light condensing unit 39a having a diameter of <NUM> is irradiated every <NUM>, the second light condensing unit 39a partially overlaps. An overlap ratio obtained by dividing an overlapping area by an area of the second light condensing unit 39a is preferably <NUM>% or more and <NUM>% or less. When the overlap ratio is less than <NUM>%, the uniformity of the appearance is impaired. When the overlap ratio exceeds <NUM>%, the productivity is reduced.

The unevenness <NUM> is oxidized along the trajectory for irradiation with the nanosecond laser <NUM>. The surface of the base material <NUM> is heated by performing irradiation with the nanosecond laser <NUM>. Since the base material <NUM> is heated in the air, the metal molecules are bonded to oxygen and are oxidized. In addition, it is presumed that protruding portions of the unevenness <NUM> are melted because heat is less likely to be dissipated. Therefore, by performing melting with the heat and oxidizing, a surface having a small surface roughness and a high glossiness is formed.

As illustrated in <FIG>, a plurality of second trajectories <NUM>, which are trajectories for irradiating with the nanosecond laser <NUM>, are arranged in parallel. The second trajectories <NUM> may be curved lines or straight lines. As a result, the unevenness <NUM> on a surface in a predetermined pattern is oxidized without gaps. In <FIG>, the first trajectories <NUM> and the second trajectories <NUM> intersect with each other. The arrangement is not limited thereto, and the first trajectories <NUM> and the second trajectories <NUM> may be parallel or may overlap each other. The first trajectories <NUM> and the second trajectories <NUM> may be unrelated trajectories.

As illustrated in <FIG>, the first processed surface <NUM> having the second pattern <NUM>, the third pattern <NUM>, the fourth pattern <NUM>, and the fifth pattern <NUM> is irradiated with the nanosecond laser <NUM>. As a result, the second processed surface <NUM> is formed in a manner of covering the first processed surface <NUM> in the second pattern <NUM>, the third pattern <NUM>, the fourth pattern <NUM>, and the fifth pattern <NUM>.

A surface of the first processed surface <NUM> is a surface formed by performing irradiation with the femtosecond laser <NUM>. Therefore, as illustrated in <FIG>, the first processed surface <NUM> has large unevenness <NUM> and a large first surface roughness. The surface of the first processed surface <NUM> is a surface formed by abrasion processing. Therefore, the metal molecules are not bonded to oxygen, and a film thickness of an oxide film <NUM> is small.

A surface of the second processed surface <NUM> is a surface formed by irradiating the first processed surface <NUM> with the nanosecond laser <NUM>. Therefore, as illustrated in <FIG>, the second processed surface <NUM> has the small unevenness <NUM> and a small second surface roughness. Since the surface of the second processed surface <NUM> is a surface heated in the air, the film thickness of the oxide film <NUM> is smaller than that of the first processed surface <NUM>.

The film thickness of the oxide film is measured according to, for example, the following method. The receiving plate <NUM> is hardened with resin. Next, the hardened resin and the receiving plate <NUM> are cut, and a cross section of the hardened resin is polished. A cross section of the resin and the receiving plate <NUM> is observed by a scanning electron microscope, and the film thickness of the oxide film <NUM> is measured.

According to this manufacturing method, in step S1, the surface of the base material <NUM> of the receiving plate <NUM> which is a metal component is irradiated with the femtosecond laser <NUM>. The femtosecond laser <NUM> is a laser having a pulse width of a femtosecond level. A predetermined pattern is formed by the first trajectories <NUM> of the femtosecond laser <NUM>. The pattern includes a figure, a character, a graphic, and the like. The abrasion processing is performed to instantaneously vaporize and disperse the metal by the femtosecond laser <NUM>. A surface on which a pattern is formed by the abrasion processing is the first processed surface <NUM>. A part of the first processed surface <NUM> is irradiated with the nanosecond laser <NUM> of the second laser. A pulse width of the second laser is equal to or greater than the pulse width of the femtosecond laser <NUM>. Therefore, an oxide film <NUM> is formed at a position irradiated with the second laser. A surface on which the oxide film <NUM> is formed is the second processed surface <NUM>. The oxide film <NUM> on the second processed surface <NUM> is thicker than the oxide film <NUM> on the first processed surface <NUM>. A surface roughness of a processed surface having the thicker oxide film <NUM> is smaller than that of a processed surface having the thinner oxide film <NUM>, resulting in a glossy surface. Therefore, the second processed surface <NUM> can be a glossy surface as compared with the first processed surface <NUM>. As a result, the second processed surface <NUM> is glossier than the first processed surface <NUM>, and therefore, the second processed surface <NUM> can have an aesthetic appearance.

According to this manufacturing method, the second laser used in step S2 is the nanosecond laser <NUM>. The nanosecond laser <NUM> is a laser having a pulse width of a nanosecond level. The nanosecond laser <NUM> can cause the first processed surface <NUM> to be the glossy second processed surface <NUM> without crushing the patterns formed by the femtosecond laser <NUM>.

On the second processed surface <NUM>, the film thickness of the oxide film <NUM> is more than <NUM> and <NUM> or less. According to this manufacturing method, the film thickness of the oxide film <NUM> on the second processed surface <NUM> is more than <NUM>, and therefore, the second processed surface <NUM> can be a glossy surface. Since the film thickness of the oxide film <NUM> on the second processed surface <NUM> is <NUM> or less, the patterns formed by performing irradiation with the femtosecond laser <NUM> can be seen without being crushed. Since the film thickness of the oxide film <NUM> on the second processed surface <NUM> is <NUM> or less, the oxide film <NUM> is transparent.

According to this configuration, the first processed surface <NUM> is formed by irradiating the base material <NUM> made of titanium, a titanium alloy, or stainless steel with the femtosecond laser <NUM>. Further, the second processed surface <NUM> is formed by irradiating the base material <NUM> with the nanosecond laser <NUM>. Since titanium, a titanium alloy, and stainless steel are difficult to be plated, it is difficult to change the appearance by plating. According to this configuration, even if a material of the timepiece component is titanium, a titanium alloy, or stainless steel that is difficult to be plated, multiple variations can be added to the appearance.

The timepiece <NUM> includes the above-described receiving plate <NUM>. According to this configuration, the above-described receiving plate <NUM> provided in the timepiece <NUM> has an aesthetic appearance. Therefore, the timepiece <NUM> can be a timepiece including a timepiece component having an aesthetic appearance.

The present embodiment is different from the first embodiment in that the first pattern <NUM> in the first region <NUM> illustrated in <FIG> is the second processed surface <NUM>. In addition, the same components as those according to the first embodiment are denoted by the same reference numerals, and a redundant description thereof will be omitted.

As illustrated in <FIG>, a timepiece <NUM> includes a receiving plate <NUM> serving as a timepiece component and a metal component. The receiving plate <NUM> includes a base material <NUM> made of metal. A material of the base material <NUM> is the same as that of the base material <NUM> according to the first embodiment.

The base material <NUM> has a first region <NUM>, a second region <NUM>, and a third region <NUM>. A surface of the base material <NUM> in the first region <NUM> and the second region <NUM> is the second processed surface <NUM>. A shape of the first region <NUM> is the first pattern <NUM>. The second processed surface <NUM> in the second region <NUM> includes four portions. Shapes of the four portions are the second pattern <NUM>, the third pattern <NUM>, the fourth pattern <NUM>, and the fifth pattern <NUM>.

The second processed surface <NUM> is formed by irradiating the first processed surface <NUM> with a second laser having a pulse width equal to or greater than the pulse width of the femtosecond laser <NUM>. Therefore, the second processed surface <NUM> is a surface covering the entire first processed surface <NUM>.

A surface roughness of the first processed surface <NUM> is a first surface roughness. A surface roughness of the second processed surface <NUM> is a second surface roughness. The second surface roughness is <NUM> or more and <NUM> or less. The second surface roughness is smaller than the first surface roughness. The receiving plate <NUM> includes the first processed surface <NUM> and the second processed surface <NUM>, and the second processed surface <NUM> covers the entire first processed surface <NUM>.

According to this configuration, the surface of the base material <NUM> includes the second processed surface <NUM>. The second processed surface <NUM> is a surface covering the first processed surface <NUM>. The first processed surface <NUM> is a surface having a larger surface roughness and a lower glossiness than those of the second processed surface <NUM>. The second processed surface <NUM> is a surface having a smaller surface roughness and a higher glossiness than those of the first processed surface <NUM>. The second processed surface <NUM> is a surface having a high glossiness, and can have an aesthetic appearance as compared with the first processed surface <NUM> having a low glossiness.

Next, a method for manufacturing the above-described receiving plate <NUM> will be described with reference to <FIG>. In the flowchart in <FIG>, the first machining process of step S1 is the same as that according to the first embodiment.

In the second machining process of step S2, the entire first processed surface <NUM> is irradiated with the second laser having a pulse width of femtoseconds or more, thereby forming a second processed surface <NUM> having a surface roughness smaller than that of the first processed surface <NUM> and having an oxide film <NUM> thicker than that of the first processed surface <NUM>. Through processes described above, the second processed surface <NUM> covering the first processed surface <NUM> is completed.

According to this manufacturing method, all positions of the first processed surface <NUM> is irradiated with the second laser. The oxide film <NUM> is formed at the positions irradiated with the second laser. A surface on which the oxide film <NUM> is formed is the second processed surface <NUM>. The oxide film <NUM> on the second processed surface <NUM> is thicker than the oxide film on the first processed surface <NUM>. A surface roughness of a processed surface having the thicker oxide film <NUM> is smaller than that of a processed surface having the thinner oxide film <NUM>, resulting in a glossy surface. Therefore, the second processed surface <NUM> can be a glossy surface as compared with the first processed surface <NUM>. As a result, the second processed surface <NUM> is glossier than the first processed surface <NUM>, and therefore, the second processed surface <NUM> can have an aesthetic appearance.

According to the first embodiment, the thickness of the oxide film <NUM> on the second processed surface <NUM> is set to <NUM> or less. The thickness of the oxide film <NUM> may exceed <NUM>. As illustrated in <FIG>, when the thickness of the oxide film <NUM> exceeds <NUM>, a colored surface is observed. By adjusting a color tone, an aesthetic appearance can be attained.

The nanosecond laser <NUM> can increase or decrease an amount of energy received by the base material <NUM> to control the film thickness of the oxide film <NUM>. Parameters caused by the amount of energy include a scanning speed, a frequency, and a laser fluence of the second light condensing unit 39a. The frequency indicates a frequency of the nanosecond laser <NUM> emitted from the irradiation unit <NUM>. For example, it is assumed that parameters other than the frequency are fixed. When it is desired to increase the film thickness, the frequency is increased to shorten the pitch of the second light condensing unit 39a. In addition, for example, it is assumed that parameters other than the scanning speed are fixed. When it is desired to increase the film thickness, the scanning speed is decreased to shorten the pitch of the second light condensing unit 39a. In this manner, the thickness of the oxide film <NUM> can be controlled by controlling the amount of energy received by the base material <NUM>.

According to the first embodiment, a manufacturing process is finished when the second processed surface <NUM> is formed by performing irradiation with the second laser. Further, the second processed surface <NUM> may be plated with various metals. By adjusting a color tone, an aesthetic appearance can be attained.

According to the first embodiment, the nanosecond laser <NUM> is emitted at regular intervals with a constant pitch. The nanosecond laser <NUM> may be emitted by gradually switching the pitch. Since the film thickness of the oxide film <NUM> gradually changes, gradation can be applied to the glossiness. By gradually increasing the film thickness of the oxide film <NUM>, gradation can be applied to the color tone. A trajectory along which the second light condensing unit 39a moves is referred to as a scanning line. Gradation can be applied in a direction of the scanning line.

Since the film thickness of the oxide film <NUM> gradually changes by gradually changing an interval between scanning lines, gradation can be applied to the glossiness. Gradation can be applied in a direction intersecting the scanning line.

According to the first embodiment, the first processed surface <NUM> and the second processed surface <NUM> are formed on the receiving plate <NUM>. According to the second embodiment, the first processed surface <NUM> and the second processed surface <NUM> are formed on the receiving plate <NUM>. In addition, the timepiece component on which the first processed surface <NUM> and the second processed surface <NUM> are formed may be any of a receiving member such as the receiving plate <NUM> and the receiving plate <NUM>, a circuit cover, an oscillating weight, a main plate, a back cover, a dial, a pointer, and a balance with hairspring.

Claim 1:
A method for manufacturing a timepiece component (<NUM>), the method comprising:
(S1) forming a first processed surface (<NUM>) having a predetermined pattern (<NUM>) by irradiating a surface of a metal component with a first laser having a pulse width of femtoseconds; and characterised in that the method further comprises :
(S2) forming a second processed surface (<NUM>) having a surface roughness smaller than that of the first processed surface by irradiating at least a part of the first processed surface with a second laser having a pulse width of femtoseconds or more, wherein
when forming the first processed surface, an oxide film (<NUM>) is formed on the first processed surface, and
when forming the second processed surface, an oxide film thicker (<NUM>) than the oxide film of the first processed surface is formed on the second processed surface.