Patent Description:
Timepieces are required to have excellent aesthetics as an ornament in addition to functionality as a useful article. To enhance a feel and quality of the appearance of the timepiece, it is known that precious metal materials are used to form a dial, a case, and other timepiece parts. However, precious metal materials are generally expensive, and excessive use of precious metal materials is required to be controlled due, for example, to the amount of reserves.

In view of the points described above, the present applicant has proposed, for example, the technologies described in <CIT>, <CIT>, and <CIT>. In <CIT>, timepiece parts having a feel and quality of the appearance comparable to those of timepiece parts made of precious metal materials are achieved by layering a color toning layer formed of a plurality of oxide films on a base having a metallic luster. Such timepiece parts are achieved by layering a plurality of oxide films to adjust the optical reflectance and a tint so that a color tone having intended brightness, saturation, and hue while making use of the metallic luster of the base. A color tone having intended brightness, saturation, and hue is also referred to as an intended color tone. Similarly, the technologies described in <CIT> and <CIT> have the following point in common with <CIT>: a color toning layer formed of a plurality of oxide films is layered on a base.

The technologies described in <CIT>, <CIT>, and <CIT>, however, have room for improvement. In detail, to obtain an intended color tone, at least <NUM> oxide films need to be layered in some cases. In such cases, the color toning layer has a complicated configuration, resulting in a problem of low productivity and film reliability. That is, there is a need for timepiece parts each having a simple configuration but exhibiting an intended color tone.

<CIT> discloses a part for a timepiece that sequentially includes a silicon-based base body, an underlying layer and an optical reflection layer. The underlying layer at least includes a first nickel layer in a surface of the base body. The optical reflection layer has a multilayer structure in which a niobium oxide layer and a silicon oxide layer are alternately deposited on each other from the side of the underlying layer, or in which the silicon oxide layer and the niobium oxide layer are alternately deposited from the side of the underlying layer.

A timepiece part according to the invention is defined in claim <NUM>.

A timepiece according to the invention includes the timepiece part described above.

<FIG> is a plan view of a timepiece according to the present embodiment.

A timepiece <NUM> according to the present embodiment is a three-hand analog wristwatch.

The timepiece <NUM> is formed of a case band <NUM>, a dial <NUM>, a second hand <NUM>, a minute hand <NUM>, an hour hand <NUM>, a crown <NUM>, and other components. The dial <NUM> corresponds to a timepiece part.

The case band <NUM> is a case and is made of hard metal, such as stainless steel or titanium. A movement <NUM> (<FIG>) that drives the indicating hands is accommodated behind the dial <NUM> in the case band <NUM>.

The dial <NUM> has a logo <NUM> and a scale <NUM> provided thereon. An insertion hole (not shown) through which shafts of the indicating hands are inserted is formed at the center of the dial <NUM>, which has a circular shape, and the second hand <NUM>, the minute hand <NUM>, and the hour hand <NUM> are attached to the shafts. The dial <NUM> does not necessarily have a circular shape and may have any shape according to the design of the dial <NUM>. For example, the dial <NUM> may have an elliptical shape or a rectangular shape or any other polygonal shape.

The crown <NUM> is provided so as to allow time correction when pulled one step. The crown <NUM> may have other functions.

The dial <NUM> includes a color toning layer <NUM> (<FIG>), which will be described later, and therefore has a luxurious appearance exhibiting a metallic luster and a deep blue color. In the present embodiment, the deep blue color having a metallic luster will be described as an example of the intended color tone. The intended color tone is a color tone having intended brightness, saturation, and hue.

<FIG> is a cross-sectional view of the dial. <FIG> is a flowchart showing the procedure of a method for manufacturing the dial. <FIG> is a plan view of a base.

The cross-sectional configuration of the dial <NUM> and the method for manufacturing the dial <NUM> will be described with reference to <FIG>.

The dial <NUM> has a configuration in which the color toning layer <NUM> is layered on a base <NUM>, as shown in <FIG>. The color toning layer <NUM> is formed of a plurality of functional films layered on each other. In detail, the color toning layer <NUM> is formed of a first oxide film <NUM>, a first metal film <NUM>, a protective film <NUM>, and a second oxide film <NUM>. In other words, the color toning layer <NUM> includes the first oxide film <NUM> and the second oxide film <NUM>, and the first metal film <NUM> and the protective film <NUM> are provided in this order between the first oxide film <NUM> and the second oxide film <NUM>.

The method for manufacturing the dial <NUM> will subsequently be described primarily with reference to <FIG> along with <FIG> and <FIG> as appropriate.

In step S1, the base <NUM> is prepared. The base <NUM> shown in <FIG> is a metal substrate that will form the base of the dial <NUM>. In the initial state, the base <NUM> has a substantially square shape, and a central portion thereof is an area where the circular dial <NUM> is formed, as shown in <FIG>. In a preferable example, the base <NUM> is a brass plate having a thickness of about <NUM>. The material of the base <NUM> is not limited to brass, and it is preferable to use a base metal as compared with precious metals, such as nickel silver, Al, Ti, V, Cr, Fe, Co, Ni, Cu, Zn, Zr, Nb, Mo, In, Sn, Hf, Ta, W, Bi, and Mg, or an alloy containing at least one of the elements described above. It is noted that inclusion of a small amount of precious metals is not precluded.

The base <NUM> is provided with two reference holes <NUM> on a diagonal line thereof, as shown in <FIG>. In a manufacturing step, the base <NUM> is placed in a jig provided with reference pins corresponding to the reference holes <NUM>, and the positioned base <NUM> is processed in the following manufacturing steps.

In a preferable example, a film deposition process in each of step S2 and the following steps is carried out by using a vacuum evaporation apparatus. The vacuum evaporation apparatus has an ion assist function and a plasma function. The ion assist function causes an ion gun to radiate ionized gas molecules that press evaporation material molecules onto a deposition receiving surface, improving adhesion of the evaporation material molecules. The plasma function facilitates an oxide reaction with the aid of introduced gas plasma to provide a sputtering effect at the deposition receiving surface. In each of the following film deposition processes, film deposition is performed with the functions described above selectively activated in accordance with the characteristics of the functional film. In the following description, using the ion assist function is referred to an ion assist activated state, and using the plasma function is referred to a plasma activated state. Furthermore, a mixture of argon and oxygen is used as a treatment gas in the plasma treatment.

In step S2, the first oxide film <NUM> is formed at the surface of the base <NUM> by using the vacuum evaporation apparatus. The first oxide film <NUM> is preferably made of an oxide of a metal material. For example, Ta<NUM>O<NUM> is deposited to form the first oxide film <NUM>.

The thickness of the first oxide film <NUM> is, for example, set at about <NUM>. The first oxide film <NUM> is not necessarily made of tantalum pentoxide and may instead be made of any other metal oxide. The first oxide film <NUM> may still instead be a laminate of a plurality of oxide films. The first oxide film <NUM> may still instead be a laminate of a plurality of oxide films. For example, the first oxide film <NUM> may be made of a material containing at least one selected from the group consisting of Ta<NUM>O<NUM>, SiO<NUM>, TiO<NUM>, Al<NUM>O<NUM>, ZrO<NUM>, Nb<NUM>O<NUM>, and HfO<NUM>. In other words, the first oxide film <NUM> includes one or more metal oxide films.

In step S3, the first metal film <NUM> is formed on the first oxide film <NUM> by using the vacuum evaporation apparatus. In a preferable example, Cr is deposited to form the first metal film <NUM>. In a preferable example, the first metal film <NUM> has a thickness of, for example, about <NUM>. The first metal film <NUM> does not necessarily have the thickness described above and may have a thickness that provides a moderate brightness adjustment effect, for example, a thickness greater than or equal to <NUM> but smaller than or equal to <NUM>. The moderate brightness adjustment effect refers to a brightness adjustment function that allows see-through observation and making use of the appearance of the base <NUM> at the intended color tone. The first metal film <NUM> is not necessarily made of Cr and may instead be made of a material containing at least one selected from the group consisting of Al, Ti, V, Cr, Fe, Co, Ni, Cu, Zn, Zr, Nb, Mo, In, Sn, Hf, Ta, W, Bi, and Mg.

In step S4, the protective film <NUM> is formed on the first metal film <NUM>. According to the invention as defined in the attached claim set, Al<NUM>O<NUM> is deposited to form the protective film <NUM>. In this process, the vacuum evaporation apparatus may be caused to operated in the ion assist deactivated state and the plasma activated state. The plasma function is activated to facilitate the alumina reaction and improve the accuracy of the refractive index of the film through the facilitated reaction. In a preferable example, the protective film <NUM> has a thickness of, for example, about <NUM>. The protective film <NUM> does not necessarily have the thickness described above and may have a thickness large enough to protect the first metal film <NUM> from the effect of the plasma treatment during the formation of the second oxide film <NUM> in the next step. A thickness greater than or equal to <NUM> is preferred for the protective film <NUM>. In devices outside the scope of protection of the attached claim set because no protective film <NUM> is provided, the first metal film <NUM> is damaged by the plasma treatment, resulting in a change in the color tone, which will be described later in detail.

In step S5, the second oxide film <NUM> is formed on the protective film <NUM>. In a preferable example, the second oxide film <NUM> is formed of two layers, an Nb<NUM>O<NUM> film and a SiO<NUM> film. Since the second oxide film <NUM> is the top layer of the color toning layer <NUM>, the vacuum evaporation apparatus preferably is caused to operate in the ion assist activated state and the plasma activated state for high-density film deposition. In a preferable example, the Nb<NUM>O<NUM> and SiO<NUM> films are both deposited in the ion assist activated state and the plasma activated state. In other words, the second oxide film <NUM> is formed of a plurality of oxide films, and the oxide films include one or more metal oxide films. The second oxide film <NUM> may instead be made of a material containing at least one selected from the group consisting of Ta<NUM>O<NUM>, SiO<NUM>, TiO<NUM>, Al<NUM>O<NUM>, ZrO<NUM>, Nb<NUM>O<NUM>, and HfO<NUM>, as the first oxide film <NUM> is. The thickness of the second oxide film <NUM> is, for example, set at about <NUM>. The second oxide film <NUM> does not necessarily have the thickness described above and may have a thickness greater than or equal to <NUM> but smaller than or equal to <NUM>.

The steps described above cause the color toning layer <NUM>, which is formed of the first oxide film <NUM>, the first metal film <NUM>, the protective film <NUM>, and the second oxide film <NUM>, to be formed on the base <NUM>, as shown in <FIG>.

The above description has been made with reference to the case where the deep blue having a metallic luster is the intended color tone, but not necessarily. The intended color tone can be any of other color tones having a variety of types of brightness, saturation, and hue according to the design of the dial, such as dark red and purple having a metallic luster.

The above description has been made with reference to the case where the base <NUM> is made of metal, but not necessarily. For example, the base <NUM> may be formed of a resin substrate. The first metal film <NUM> is a thin film having a brightness adjustment effect of transmitting a certain amount of light, but still has a certain metallic luster because the first metal film <NUM> is made of metal. Therefore, when the metallic luster required for the intended color tone is satisfied by the metallic luster of the first metallic film <NUM>, the base <NUM> may be made of a material having no metallic luster such as resin. In this case, the base material <NUM> can be made, for example, of a glass material such as sapphire glass, soda glass, crystalline glass, quartz glass, lead glass, potassium glass, borosilicate glass, and alkali-free glass, a ceramic material such as alumina and titania, or a plastic material such as a variety of thermoplastic resins and a variety of curable resins.

<FIG> is a graphical diagram for comparing spectral data produced by different toning layers. In <FIG>, the horizontal axis represents the wavelength in nm and the vertical axis represents the reflectance.

A graph <NUM> in <FIG> shows spectral data on the spectrum produced by the dial <NUM> including the color toning layer <NUM> in <FIG>. A graph <NUM> is Comparative Example and shows spectral data in a case where the protective film <NUM> is not provided. A graph <NUM> is Comparative Example and shows spectral data in a case where neither the first metal film <NUM> nor the protective film <NUM> is provided. The graphs were derived from results of a simulation based on results of experiments conducted by the inventor and others.

First, the intended color tone of the dial <NUM> including the color toning layer <NUM> is the deep blue having a metallic luster, as described above, which, when profiled in <FIG>, has a peak at a wavelength of about <NUM>, and the reflectance at the peak needs to be greater than or equal to <NUM>% but smaller than or equal to <NUM>%. The reflectance at a wavelength of about <NUM> is preferably smaller than or equal to <NUM>%.

In view of the requirements described above, the graph <NUM>, which peaks at the wavelength of about <NUM>, where the reflectance is <NUM>%, matches the intended profile. Furthermore, since the reflectance at the wavelength of about <NUM> is smaller than <NUM>%, it is recognized that the intended color tone is substantially reproduced.

In contrast, the graph <NUM> in Comparative Example peaks at a wavelength of about <NUM>, where the reflectance is about <NUM>%, and therefore does not match the intended profile and results in a bright purplish color tone. The reason for this is that during the formation of the second oxide film <NUM> in step S5 in the absence of the protective film <NUM>, the Nb<NUM>O<NUM> film was formed directly on the first metal film <NUM> in the plasma-activated state, so that the refractive index of the Cr film changed due to alterations including oxidation of the Cr film itself, which changed how the interference occurred in the entire color toning layer <NUM>, resulting in a deviation from the intended color tone.

The graph <NUM> in Comparative Example, which peaks at a wavelength of about <NUM>, where the reflectance is about <NUM>%, does not match the intended profile and results in a bright purple color tone. Furthermore, the reflectance at the wavelength of about <NUM> is about <NUM>%, so that a bright color tone is provided over the entire wavelength range. The reason for this is that the absence of the first metal film <NUM> having a brightness adjustment function makes the color tone too bright over the entire wavelength range, so that none of the intended brightness, saturation, and hue can be obtained.

As described above, the dial <NUM> and the timepiece <NUM> according to the present embodiment can provide the effects below.

The dial <NUM> as the timepiece part includes the base <NUM> and the color toning layer <NUM> provided on the base <NUM>. The color toning layer <NUM> includes the first oxide film <NUM>, the first metal film <NUM>, the protective film <NUM>, and the second oxide film <NUM>. The first oxide film <NUM> is provided between the base <NUM> and the second oxide film <NUM>. Between the first oxide film <NUM> and the second oxide film <NUM>, the first metal film <NUM> and the protective film <NUM> are provided in this order from the side facing the first oxide film <NUM>.

According to the configuration described above, unlike the related-art technology in which the color toning layer is formed of a plurality of oxide films, providing the first metal film <NUM> having a brightness adjustment function between the first oxide film <NUM> and the second oxide film <NUM> allows formation of a color toning layer formed of fewer films than in the related-art color toning layer but having a comparable color toning function. In other words, the fewer films allows excellent productivity and high reliability in the individual functional films.

The intended color tone can therefore be provided by the color toning layer <NUM> having the simple configuration.

The dial <NUM> having the simple configuration but exhibiting the intended color tone can therefore be provided.

It is preferable that the first metal film <NUM> has a thickness greater than or equal to <NUM> but smaller than or equal to <NUM>.

Therefore, when the first metal film <NUM> has an optimum thickness according to the intended color tone but being greater than or equal to <NUM> but smaller than or equal to <NUM>, an optimum brightness adjustment function that allows transmission of a fixed amount of light can be provided. In other words, a first metal film <NUM> having an optimal brightness adjustment function that makes use of the appearance of the base <NUM> can be formed.

It is further preferable that the first oxide film <NUM> includes one or more metal oxide films.

The thus configured first oxide film <NUM> can optimize the brightness adjustment properties of the color toning layer <NUM>.

It is further preferable that the second oxide film <NUM> is formed of a plurality of oxide films, and that the oxide films include one or more metal oxide films.

The thus configured second oxide film <NUM> can optimize the brightness adjustment properties of the color toning layer <NUM>.

It is further preferable that the metal oxide film is made of a material containing at least one selected from the group consisting of Ta<NUM>O<NUM>, SiO<NUM>, TiO<NUM>, Al<NUM>O<NUM>, ZrO<NUM>, Nb<NUM>O<NUM>, and HfO<NUM>.

The thus configured metal oxide film can optimize the brightness adjustment properties of the color toning layer <NUM>.

It is further preferable that the first metal film <NUM> is made of a material containing at least one selected from the group consisting of Al, Ti, V, Cr, Fe, Co, Ni, Cu, Zn, Zr, Nb, Mo, In, Sn, Hf, Ta, W, Bi, and Mg.

The thus configured first metal film <NUM> can allow selection of a metallic luster in accordance with the intended color tone.

According to the invention as defined in the attached claim set, the protective film <NUM> is made of Al<NUM>O<NUM>.

The thus configured protective film <NUM> can protect the first metal film <NUM>, whereby the intended color tone can be obtained.

The timepiece <NUM> includes the dial <NUM>.

The timepiece <NUM> including the dial <NUM> exhibiting the intended color tone can therefore be provided.

<FIG> is a cross-sectional view of a dial <NUM> according to the present embodiment and corresponds to <FIG>. The aforementioned embodiment has been described with reference to the case where the color toning layer <NUM> forms the top surface of the dial, however, a clear layer <NUM> may be provided on the color toning layer <NUM>. In the following description, the same constituent portions as those in the first embodiment have the same reference characters and will not be redundantly described.

The dial <NUM> according to the present embodiment includes a buffer layer <NUM>, the color toning layer <NUM>, and the clear layer <NUM> layered in this order on the base <NUM>, as shown in <FIG>. In a preferable example, the clear layer <NUM>, which forms the top surface, is made of acrylic resin. Acrylic resin has a coefficient of linear expansion greater than that of the oxide films that form the color toning layer <NUM> and therefore shrinks by a large amount due to a change in temperature. In view of the fact described above, providing the buffer layer <NUM>, which has a coefficient of linear expansion close to that of the clear layer <NUM>, between the base <NUM> and the color toning layer <NUM> prevents the color toning layer <NUM> from peeling off due to the shrinkage of the clear layer <NUM>.

The buffer layer <NUM> is formed of a SiO<NUM> film in a preferable example. The SiO<NUM> film is formed by using the vacuum evaporation apparatus operating in the ion assist activated state and the plasma activated state. In a preferable example, the buffer layer <NUM> has, for example, a thickness of about <NUM>. The buffer layer <NUM> does not necessarily have the thickness described above and may have a thickness that allows reduction in the thermal shrinkage resulting from a change in the temperature of the clear layer <NUM>, for example, a thickness greater than or equal to about <NUM>. Furthermore, the buffer layer <NUM> is not necessarily formed of an SiO<NUM> film and may be made of any light transmissive material having a coefficient of linear expansion close to the coefficient of linear expansion of the clear layer <NUM>.

In a preferable example, the clear layer <NUM> is formed by applying acrylic resin onto the entire surface of the base <NUM> by using a paint liquid discharger. After the application, the base <NUM> may be rotated to allow the resultant centrifugal force to perform diffusive application of the paint liquid across the entire surface of the base <NUM>. Still instead, the clear layer <NUM> may be formed by spray painting, spin coating, ink jetting, screen printing, or any other method.

The paint liquid is not limited to acrylic resin and may be any non-conducting transparent resin material, for example, cellulose resin, polyurethane resin, and acrylic lacquer resin.

As described above, the dial <NUM> according to the present embodiment can provide the following effects in addition to the effects provided by the first embodiment described above.

The dial <NUM> includes the clear layer <NUM> at the top surface of the dial <NUM>, and the buffer layer <NUM> is provided between the base <NUM> and the color toning layer <NUM>.

Therefore, even when the clear layer <NUM> shrinks, the buffering effect of the buffer layer <NUM> prevents the color toning layer <NUM> from peeling off.

Furthermore, providing the clear layer <NUM> at the top surface of the dial <NUM> increases three-dimensionality and transparency, making the appearance of the dial <NUM> more luxurious.

<FIG> is a cross-sectional view of a dial <NUM> according to the present embodiment and corresponds to <FIG>.

In the configuration shown in <FIG>, a second metal film <NUM> may be provided between the buffer layer <NUM> and the color toning layer <NUM>. The second metal film <NUM> is provided to cancel the tinge of the color of the base <NUM>. In the following description, the same constituent portions as those in the first embodiment have the same reference characters and will not be redundantly described.

The dial <NUM> according to the present embodiment includes the buffer layer <NUM>, the second metal film <NUM>, the color toning layer <NUM>, and the clear layer <NUM> layered in this order on the base <NUM>, as shown in <FIG>. In a preferable example, the second metal film <NUM> is a Cr film. The Cr film is formed by using the vacuum evaporation apparatus. In a preferable example, the second metal film <NUM> has, for example, a thickness of about <NUM>. The second metal film <NUM> does not necessarily have the thickness described above and may have a thickness that prevents see-through observation of the underlying base <NUM>, for example, a thickness greater than or equal to about <NUM>. The second metal film <NUM> is not necessarily formed of a Cr film, and may be formed of any metal film having a tinge according to the intended color tone. For example, the second metal film <NUM> can be made of the same material of the first metal film <NUM>.

As described above, the dial <NUM> according to the present embodiment can provide the following effect in addition to the effects provided by the embodiments described above.

The dial <NUM> includes the second metal film <NUM> between the buffer layer <NUM> and the color toning layer <NUM>.

Therefore, providing the second metal film <NUM> allows expression of a tinge different from that of the color of the base <NUM>. The dial <NUM> exhibiting a greater variety of color tones can therefore be provided.

<FIG> is a cross-sectional view of a timepiece taken along the line b-b in <FIG>.

The timepiece <NUM> according to the present embodiment is formed of the case band <NUM>, a windshield <NUM>, the crown <NUM>, a case back <NUM>, a case back glass plate <NUM>, and the like. The case band <NUM> accommodates the dial <NUM>, the movement <NUM>, a main plate <NUM>, an oscillating weight <NUM>, and other components.

The timepiece <NUM> is a skeleton model that allows observation of the oscillating weight <NUM> and the main plate <NUM> inside the case band <NUM> through the case back glass plate <NUM>.

The aforementioned embodiments have been described with reference to the dial <NUM>, which includes the color toning layer <NUM>, as an example of the timepiece part, but not necessarily, and the present disclosure is applicable to a variety of timepiece parts. For example, the case band <NUM>, the crown <NUM>, the case back <NUM>, and a band (not shown), which are each made of a metal material, may be provided with the color toning layer <NUM>.

The oscillating weight <NUM> and the main plate <NUM> are internal mechanical parts each made of a metal material. In the case of the skeleton model, the parts described above are part of the appearance and may therefore be provided with the color toning layer <NUM> or the clear layer <NUM>. Screws that fix the oscillating weight <NUM>, wheel trains, and bearings (none of which are shown) may also be provided with the color toning layer <NUM> or the clear layer <NUM>.

Claim 1:
A timepiece part (<NUM>) comprising:
a base (<NUM>); and
a color toning layer (<NUM>) provided on the base,
wherein the color toning layer includes a first oxide film (<NUM>), a first metal film (<NUM>), a protective film (<NUM>), and a second oxide film (<NUM>),
the first oxide film (<NUM>) is provided between the base (<NUM>) and the second oxide film (<NUM>), and
between the first oxide film (<NUM>) and the second oxide film (<NUM>), the first metal film (<NUM>) and the protective film (<NUM>) are provided in a presented order from a side facing the first oxide film,
characterized in that the protective film (<NUM>) is made of Al<NUM>O<NUM>.