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(11) | EP 1 286 234 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
| published in accordance with Art. 158(3) EPC |
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| (54) | RADIOWAVE WRISTWATCH CASE |
| (57) A casing of a radio-controlled wristwatch comprises a casing base body through which
a radio wave can transmit, and a thin film covering all or part of an exterior surface
of the casing base body and having a surface assuming a metallic color. The casing
base body comprises a casing main body portion and a back lid portion, all or a substantial
part of the casing main body portion and/or all or a substantial part of the back
lid portion being made of a material having a radio wave transmissive property. The
material having a radio wave transmissive property consists of a ceramic or glass.
The thin film having a surface assuming a metallic color consists of a metal or metallic
compound. Thus, it is possible to accommodate not only a watch unit but also an antenna
unit in the casing to thereby provide a radio-controlled wristwatch with a built-in
antenna that has a luxurious appearance and allows for a greater freedom of design. |
TECHNICAL FIELD
[0001] The present invention relates to a casing of a radio-controlled wristwatch that can provide an air of luxury, a method for manufacturing such a casing, and a radio-controlled wristwatch having a built-in antenna and using such a casing to offer a luxurious appearance.
BACKGROUND TECHNOLOGY
[0002] A base body of a casing of a luxury wristwatch is generally made of a metallic material (such as stainless steel, for example). In order to enhance the luxurious appearance of the watch, an ornamental metal such as platinum, palladium, gold, silver, etc., is often deposited on a surface of the casing base body by means of plating, for example. Besides, luxury watch fanciers have a strong tendency to prefer a wristwatch appearance assuming a metallic color (inclusive of a metallic luster). For this reason, it is difficult to sell wristwatches using a non-metallic material such as a plastic or ceramic on their exterior at high prices even though the watches have a high quality in performance. The tendency of preferring wristwatches having a metallic color appearance is common between the consumers worldwide, and particularly can be seen among the consumers in Japan or Europe.
[0003] Radio-controlled watches, which operate under a basic mechanism of receiving a radio wave time signal and automatically adjusting the time displayed on the wristwatches according to the received signal, can theoretically achieve the most precisely controlled time display. In addition, if the time information carried on the radio wave time signal is properly controlled, it is possible, for example, to beneficially remove the inconvenience of adjusting the time of the watches at each transition between the summertime and the wintertime when the daylight-saving-time system is adopted. Considering these features, the radio-controlled wristwatches should be classified into luxury or high-quality wristwatches.
[0004] Even with such high-quality, however, the sales prices of the radio-controlled wristwatches are relatively low because their appearance tends to be insufficient in view of luxury. The main reason for this is that the casing of the radio-controlled wristwatch need be made of such materials as a plastic or ceramic that does not prevent the radio wave time signal from passing through the casing. In other words, if a metallic material such as stainless steel were used as the material for forming the casing base body, the radio wave time signal could not sufficiently pass through the casing base body, to thereby cause a problem in the time calibration function.
[0005] Thus, in order to allow a metallic casing having luxurious appearance to be used in the radio-controlled wristwatch, several proposals have been made in the past.
[0006] In one such proposal (a first proposal), a metallic material such as stainless steel or titanium that can offer an air of luxury is used as the material of the base body of the watch casing, while an antenna for receiving the radio wave time signal is provided with a special shape so that the antenna is embedded in a wristband made of a radio wave-transmissive material such as a leather or nylon.
[0007] In another proposal (a second proposal), the watch casing comprises two parts that are joined to each other, wherein one of the two parts accommodates an antenna unit while the other of the two parts accommodates a watch unit, and the part that accommodates the antenna unit is made of a plastic through which a radio wave can pass. The part for accommodating the watch unit is made of a metallic material that offers a feeling of luxury.
[0008] As to the first proposal, however, the following problems have been pointed out: 1) the cost for the antenna is quite high because of its special shape; 2) the reliability of the connection between the watch unit inside the casing and the antenna unit inside the wristband tends to be low; 3) the wristband, in which the antenna is embedded, cannot be made of a metallic material, which imposes undesired limitation to the freedom of ornamentation and design thereof; and 4) replacement of the wristband would be quite cumbersome because it would require removing the antenna out of the used wristband; setting the removed antenna into the new wristband; connecting the antenna to the watch unit, etc. (it should be noted that the wristband made of a leather or nylon can be easily stained or damaged by the dust, trash, sweat, etc., and usually need be replaced every half-year or every year at the longest when it is worn by a user at all times).
[0009] As to the second proposal, the following problems have been pointed out: 1) the ornamentation or design incompatibility between the plastic part of the casing for accommodating the antenna unit and the metallic part of the casing for accommodating the watch unit cannot be resolved even when the plastic part of the casing is processed by painting or the like; and 2) the connection between the metallic part and plastic part of the casing tends to be complicated and thus expensive.
[0010] The present invention is made to solve the above problems, and an object of the present invention is to provide a casing of a radio-controlled wristwatch that is suitable for implementing a radio-controlled wristwatch having a luxurious appearance.
[0011] Another object of the present invention is to provide a method for manufacturing a casing of a wristwatch that is suitable for implementing a radio-controlled wristwatch having a luxurious appearance.
[0012] A yet another object of the present invention is to provide a radio-controlled wristwatch having a luxurious appearance.
[0013] Other and further objects and effects of the present invention will be appreciated easily by a person having ordinary skill in the art from the following description of the present invention.
DISCLOSURE OF THE INVENTION
[0014] A casing of a radio-controlled wristwatch according to the present invention comprises a casing base body through which a radio wave can transmit, a thin film covering all or part of an exterior surface of the casing base body and having a surface assuming a metallic color.
[0015] The "casing base body" herein broadly refers to an outer body constituting a wristwatch casing. The casing base body generally comprises a casing main body portion and a back lid portion. As described more fully below, the casing main body portion is a portion for accommodating a watch unit and an antenna unit all together, and generally has a front side formed with an opening for exposing a time display member such as a dial (in case of an analogue watch) or a liquid crystal display (in case of a digital watch) and a back side formed with an opening for allowing maintenance and the like. Generally, a window glass is fitted into the front side opening of the casing main body, while the back lid is fitted into the back side opening of the casing main body.
[0016] As is apparent from the language "a casing base body through which a radio wave can transmit", the casing base body must have a radio wave transmissive property. It should be noted, however, that the meaning of "a radio wave can transmit" must be interpreted on a basis of a criteria that if or not an antenna inside the casing can successfully receive a radio wave time signal in an assumed reception area. Also, so long as the casing can allow a radio wave to be transmitted therethrough, it is not necessary that the whole part of the casing base body is made of a radio wave transmissive material (e.g., plastic or ceramic). Further, the casing base body of the present invention may not have to be made of a single material. In other words, the casing base body of the present invention does not particularly exclude a two-layer or multi-layer structure comprising different materials or a structure partly comprising a two-color-part configuration as long as the casing can allow radio wave to be transmitted therethrough.
[0017] All or part of an exterior surface of the casing base body is covered by a thin film having a surface assuming a metallic color. Herein, the "thin film having a surface assuming a metallic color" is provided in order to achieve an object of the present invention of providing a luxurious appearance to the casing. Thus, so long as the thin film has a surface assuming a metallic color, any material or internal structure thereof (such as a single layer or multi-layer) may be used. However, taking into account the characteristics of currently available materials, it is considered at this time that the thin film can be preferably embodied by a thin metallic film or a thin metallic compound film. The term "thin film" herein is intended to mean that the thin film does not hinder the radio wave transmission through the casing in a general meaning. Therefore, the thickness of the thin film should be judged based on a criteria that if or not an antenna inside the casing can successfully receive a radio wave time signal in an assumed reception area.
[0018] As is apparent from the language "all or part of an exterior surface of the casing base body", the thin film having a surface assuming a metallic color may not be necessarily deposited on all of the exterior surface of the casing base body. Where on the exterior surface of the casing base body and to what extent of area the thin film assuming a metallic color should be deposited is considered a design matter that should be determined depending on a particular shape of a wristwatch or a particular design concept of a designer. In order to meet the preoccupation of the consumers that the casing of luxury wristwatches should assume a metallic color, however, it would be required for the thin film to cover a substantial part of the exterior surface of the casing base body which may include all or an exposed part of the exterior surface of the casing base body.
[0019] According to the configuration of the present invention described above, neither of the casing base body nor the metallic color assuming thin film deposited on the casing base body hinders the radio wave time signal transmission, and therefore, not only the watch unit but also the antenna unit is allowed to be accommodated in the casing, whereby it is possible to provide a radio-controlled wristwatch that has a built-in antenna and assumes a satisfactorily luxurious appearance, without imposing any undesirable limitation to the wristwatch design. In such a radio-controlled wristwatch with a built-in antenna, it should be appreciated that, unlike the conventional wristwatch with an external antenna (referring to the antenna of a type that is accommodated in a leather wristband or a plastic case specifically made therefor), there is no concern about such problems as undesirable design limitation to the wristband or the outer shape of the casing, bad connection between the antenna unit and the watch unit, cumbersome work required for antenna removing and setting in a wristband replacement, etc.
[0020] In one preferred embodiment of the present invention, the casing base body comprises a casing main body portion and a back lid portion, with all or a substantial part of the casing main body portion and/or all or a substantial part of the back lid portion being made of a material having a radio wave transmissive property.
[0021] Selection of the material of the casing base body should be done based on comprehensive consideration of not only the radio wave transmissive property of the material but also to the strength as a watch casing, molding efficiency, and the material of the metallic color assuming thin film deposited on the casing base body as well as the method of the deposition.
[0022] According to an intensive research of the inventors of the present invention, ceramics are considered preferable as the material of the casing base body (e.g., the casing main body or the back lid) since the ceramics have a favorable radio wave transmissive property, are easy to mold into an arbitrary shape, and have a good heat-resistant property that would be required in a thin film deposition process. Among the ceramics, zirconia (ZrO2) and the like is particularly preferred as the material of the casing base body when such properties as toughness and shock-resistance are also considered. The inventors have also found that the back lid, which does not require a very high strength, can be constituted by a stainless steel ring forming an outer frame and a glass plate fitted therein.
[0023] According to an intensive research of the inventors of the present invention, although the thin film on the casing base body can consist of a metal or an alloy thereof, metallic compounds are particularly preferred as the thin film material because they assume a metallic color or metallic luster, have little or no magnetic properties, and have a small electron mobility. Further, considering the radio wave transmissive property, it has been concluded that the thickness of the film is preferably in a rage of 0.01 to 5.0µm. If the film thickness were less than 0.01µm, the film of any material would be easily removed due to abrasion, while if the thin film thickness were greater than 5.0 µm, the surface texture would be rough, resulting in a poor appearance.
[0024] According to an intensive research of the inventors of the present invention, among the metallic compounds, TiN, TiC, TiO, TiCN, CrN, TaC, with or without Au, Ag, Rh, Pd or Pt being added thereto, are particularly preferred because they have a favorable hardness (HV800-3,200) and are preferable in an aesthetic point of view (they assume a color of gold, silver-white, blue, purple, etc. with metallic luster). Among the metals, Au, Ag, Pd, Pt, Rh, Ti, Ta, Cr, Al, Ni, Cu or an alloy thereof can be used.
[0025] According to an intensive research of the inventors of the present invention, in order to enhance the feeling of luxury even more by providing a rare-metal tinge to the casing surface, it is preferable that the thin film on the surface of the casing base body has a two-layer structure comprising a lower layer consisting of a metal or a metallic compound and an upper layer consisting of an ornamental metal.
According to an intensive research of the inventors of the present invention, in view of the radio wave transmission, it is preferable that the lower layer consisting of a metal or a metallic compound has a thickness of 0.01-5.0µm and the upper layer consisting of an ornamental metal has a thickness of 0.1-8.0 µm. If the thickness were less than 0.1µm, the layer of any material would be easily removed due to abrasion, while if the thickness were greater than 8.0 µm, the radio wave receiving sensitivity of the antenna would be significantly lowered.
According to an intensive research of the inventors of the present invention, it is preferable that in the case that the lower layer consists of a metal, the metal is Au, Ag, Pd, Pt, Rh, Ti, Ta, Cr, Al, Ni, Cu or an alloy thereof while in the case that the lower layer consists of a metallic compound, the metallic compound is TiN, TiC, TiO, TiCN, CrN or TaC with or without Au, Ag, Rh, Pd or Pt being added thereto, and the upper layer consisting of an ornamental metal consists of Pt, Pd, Ag, Rh, Cr or Au.
In a manufacturing method according to the present invention, a PVD (Physical Vapor Deposition) technique or CVD (Chemical Vapor Deposition) technique is preferably used in forming a thin film of a metallic compound on all or part of an exterior surface of the radio wave transmissive casing base body. The PVD technique can include: vapor deposition; sputtering; ion plating, etc. The CVD technique can include: thermal CVD; plasma CVD; optical CVD, etc.
In one preferred embodiment of the manufacturing method of the present invention, an ion plating technique is used in depositing a thin film consisting of a metallic compound on all or part of an exterior surface of a radio wave transmissive casing base body using a ceramic as its material.
The "ion plating technique" herein refers to a thin film deposition technique in which part of vaporized particles are ionized in a vacuum condition in order to give high kinetic energy to the ionized particles, whereby the formed thin film can more strongly adhere to the casing base body and have an improved quality, with a higher reactivity with a reaction gas.
As described above, in such a manufacturing method, the ceramic used as the material of the casing preferably consists of ZrO2 or the like. Also, the thickness of the thin film of a metallic compound is preferably 0.01-5.0 µm. Further, it is preferable that the metallic compound is TiN, TiC, TiO, TiCN, CrN or TaC, with or without Au, Ag, Rh, Pd or Pt being added thereto.
In another manufacturing method according to the present invention, it is preferred that a PVD technique or CVD technique is used in forming a lower thin film layer consisting of a metallic compound on all or part of an exterior surface of a radio wave transmissive casing base body, and then, a wet plating technique is used to form an upper thin film layer of an ornamental metal on the metallic compound film layer.
In a preferred embodiment of the manufacturing method of the present invention, an ion plating technique is used in forming a thin film consisting of a metallic compound on all or part of an exterior surface of a radio wave transmissive casing base body using a ceramic as its material, and subsequently a wet plating is used to form a thin film of an ornamental metal on the metallic compound film layer.
As described above, in such a method, the ceramic used as the material of the casing preferably consists of ZrO2 or the like. Also, it is preferred that the thickness of the metallic compound thin film is 0.01-5.0 µm and the thickness of the ornamental metal thin film is 0.1-8.0 µm. Further, it is preferable that the metallic compound is TiN, TiC, TiO, TiCN, CrN or TaC, with or without Au or Pt being added thereto, and the ornamental metal is Pt, Pd, Ag, Rh, Cr or Au. A radio-controlled wristwatch according to the present invention is such one with a built-in antenna that comprises a watch unit and an antenna unit accommodated in a common casing so that the antenna unit can receive a radio wave time signal through the casing that is embodied by either one of the above described casings assuming a metallic color.
Accordingly, since the radio-controlled wristwatch of the present invention has an appearance assuming a metallic color or metallic luster, it can satisfy the preference of luxury wristwatch fanciers, and thus rendering it easy to trade the wristwatch at a proper price corresponding to the high performance of the wristwatch.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026]
Figure 1 is a drawing for showing a first embodiment (before thin film deposition) of a casing of a radio-controlled wristwatch according to the present invention;
Figure 2 is a drawing for showing a first embodiment (after thin film deposition) of a casing of a radio-controlled wristwatch according to the present invention;
Figure 3 is a drawing for showing a second embodiment (before thin film deposition) of a casing of a radio-controlled wristwatch according to the present invention;
Figure 4 is a drawing for showing a second embodiment (after thin film deposition) of a casing of a radio-controlled wristwatch according to the present invention;
Figure 5 is a drawing for showing a third embodiment (before thin film deposition) of a casing of a radio-controlled wristwatch according to the present invention;
Figure 6 is a drawing for showing a third embodiment (after thin film deposition) of a casing of a radio-controlled wristwatch according to the present invention;
Figure 7 is an enlarged cross-sectional view of a front surface of a casing for explaining an example of a thin film structure;
Figure 8 is an enlarged cross-sectional view of a front surface of a casing for explaining another example of a thin film structure;
Figure 9 is a flowchart for schematically showing a first embodiment of a method for manufacturing a casing of a radio-controlled wristwatch according to the present invention;
Figure 10 is a flowchart for schematically showing a second embodiment of a method for manufacturing a casing of a radio-controlled wristwatch according to the present invention;
Figure 11 is a cross-sectional view for showing a structure of a radio-controlled wristwatch manufactured by applying the present invention;
Figure 12 is a drawing for showing an assembled state of a radio-controlled wristwatch manufactured by applying the present invention; and
Figure 13 is an explanatory drawing for showing a configuration of an apparatus for testing the wristwatch according to the present invention.
BEST MODE FOR PRACTICING THE INVENTION
[0027] In the following, preferred embodiments of the present invention are described with reference to the appended drawings.
[Embodiments of a Casing of a Radio-controlled Wristwatch]
[0028] A first embodiment of a casing of a radio-controlled wristwatch according to the present invention is shown in Figures 1 and 2. Figures 1(a)-(c) are a front view (a), side view (b) and back view (c), respectively, of a casing base body in a state that a thin film assuming a metallic color has not yet been deposited on a surface of the casing base body, while Figures 2(a)-(c) are a front view (a), side view (b) and back view (c), respectively, of the casing base body in a state that a thin film assuming a metallic color has been deposited on a surface of the casing base body.
[0029] A second embodiment of a casing of a radio-controlled wristwatch according to the present invention is shown in Figures 3 and 4. Figures 3(a)-(c) are a front view (a), side view (b) and back view (c), respectively, of a casing base body in a state that a thin film assuming a metallic color has not yet been deposited on a surface of the casing base body, while Figures 4(a)-(c) are a front view (a), side view (b) and back view (c), respectively, of the casing base body in a state that a thin film assuming a metallic color has been deposited on a surface of the casing base body.
[0030] A third embodiment of a casing of a radio-controlled wristwatch according to the present invention is shown in Figures 5 and 6. Figures 5(a)-(c) are a front view (a), side view (b) and back view (c), respectively, of a casing base body in a state that a thin film assuming a metallic color has not yet been deposited on a surface of the casing base body, while Figures 6(a)-(c) are a front view (a), side view (b) and back view (c), respectively, of the casing base body in a state that a thin film assuming a metallic color has been deposited on a surface of the casing base body.
[0031] In Figures 1-6, a reference numeral 1 refers to a main body portion of the casing base body, a reference numeral 2 refers to a window for time display into which a glass plate is fitted, a reference numeral 3 refers to a back lid portion of the casing base body, a reference numeral 4 refers to an opening for accommodating operation buttons, and a reference numeral 5 refers to an opening for attachment of a wristband.
[0032] In Figures 2, 4 and 6, shaded regions indicate areas in an outer surface of the casing base body covered by a thin film that assumes a metallic color, and a white regions indicate areas in the outer surface of the casing base body not covered by the thin film that assumes a metallic color (i.e., in those regions the ceramic material is exposed to the surface).
[0033] As is apparent from the first to third embodiments, the outer shape of the casing base body may be selected from various shapes having different thickness and designs such as a square, rectangle, circle, ellipse, etc. according to various needs.
[0034] The material of the casing base body may be a ceramic such as zirconia (ZrO2) or the like that has a favorable toughness and shock-resistance and would not hinder transmission of radio wave time signals.
As a molding process of the casing base body, injection molding technique, which can achieve higher dimensional accuracy easily and allow a greater design freedom with respect to the shape, may be used.
The thin film of which surface assumes a metallic color is deposited at least on an outer surface of the casing base body (as the case may be, also on an inner surface of the casing base body) in such a manner that the thin film covers all of the outer surface of the casing base body in the embodiment of Figures 1 and 2, the thin film covers all of the outer surface of the casing main body portion 1 but does not cover the back lid portion 3 of the casing base body in the embodiment of Figures 3 and 4, and the thin film covers only an outer marginal portion surrounding the glass plate of the outer surface of the casing base body in the embodiment of Figures 5 and 6. Thus, which part of the casing base body and to what extent the metallic color assuming thin film should cover is determined by comprehensive consideration of the radio wave time signal transparency, ornamental effect of the thin film in offering luxurious feeling, etc.
Figure 7 schematically shows an enlarged cross-sectional view of a casing surface for explaining an example of a structure of the thin film. This drawing shows a band attachment bracket portion of the casing in Figures 5 and 6, and a reference numeral 6 refers to a ceramic layer constituting the casing base body and a reference numeral 7 refers to the thin film assuming a metallic color deposited on the outer surface of the casing base body.
In this example, the thin film 7 consists of a metallic compound formed by means of an ion plating technique. The thickness of the thin film 7 is set at 0.01-5.0 µm to achieve sufficient radio wave time signal transparency. If the film thickness were less than 0.01 µm, the film of any material would be easily removed due to abrasion, while if the thin film thickness were greater than 5.0 µm, the surface texture would be rough, resulting in an unsatisfactory appearance.
A particular metallic compound to be adopted is determined according to a desired tint of metallic color. The following table 1 and table 2 show the relationship between metals or metallic compounds and their metallic color.
[Table 1]
| Relationship between Metals and Their Metallic Color | |
| - metal- | - color - |
| Au | gold |
| Ag | silver-white with warm tinge |
| Pd | silver-white |
| Pt | grayish silver-white |
| Rh | grayish silver-white |
| Ti | gray |
| Ta | light gray |
| Cr | cold silver-white |
| Al | silver |
| Ni | silver-white |
| Cu | copper |
[Table 2]
| Relationship between Metallic Compounds and Their Metallic Color | |
| - metallic compound- | - color - |
| titanium nitride (TiN) | gold |
| titanium carbide (TiC) | gray through black |
| titanium oxide (TiO) | violet, indigo |
| chromium nitride (CrN) | silver-white |
| (TiCN) | purple |
| (1)-(5) with Au added thereto | light gold with luxurious feeling |
| (1)-(5) with Ag added thereto | silver-white with warm tinge |
| (1)-(5) with Rh added thereto | silver-white with luxurious feeling |
| (1)-(5) with Pt added thereto | silver-white with warm tinge |
[0035] Figure 8 schematically shows an enlarged cross-sectional view of a casing surface for explaining another example of the thin film structure. In this drawing, a reference numeral 6 refers to a ceramic layer constituting the casing base body and a reference numeral 8 refers to a thin film having a two-layer structure deposited on the outer surface of the casing base body.
In this example, the thin film 8 comprises a lower layer 8a consisting of a metallic compound formed by means of an ion plating technique and an upper layer 8b consisting of an ornamental metal formed by means of a wet plating technique. The thickness of the lower layer 8a is set at about 0.4 µm. In determining a particular metallic compound to be adopted to constitute the lower layer 8a, consideration is made as to a desired tint of metallic color as well as its function as a base electrode in the wet plating.
As the material for constituting the lower layer 8a, TiN or the like may be used, for example. On the other hand, the thickness of the upper layer 8b consisting of an ornamental metal is set at about 2.0 µm. In determining a particular ornamental metal to be adopted to constitute the upper layer 8b, consideration is made as to a desired tint of metallic color and an abrasion-resistant property, etc. Table 3 shows the relationship between metallic compounds and their metallic color.
[Table 3]
| Relationship between Ornamental Metals and Their Metallic Color | |
| - ornamental metal- | - color - |
| platinum (Pt) | silver-white through silver-gray |
| palladium (Pd) | silver-white |
| gold (Au) | gold |
[Embodiments of a Method for Manufacturing a Casing of a Radio-controlled Wristwatch]
[0036] Figure 9 is a flowchart for schematically showing a first embodiment of a method for manufacturing a casing of a radio-controlled wristwatch according to the present invention.
The first embodiment of the method of manufacturing a casing comprises a process for manufacturing a casing base body (Figure 9(a)), a process for cleaning the casing base body (Figure 9(b)), and a process for depositing a metallic color thin film (Figure 9(c)).
[1] Casing Base Body Manufacturing Process
[0037] As shown in Figure 9(a), in this process, injection molding and sintering techniques are used to obtain a casing base body made of a ceramic. Specifically, the casing base body manufacturing process comprises steps of heating and mixing the molding material, injection molding, degreasing, sintering, and polishing (steps 901-905). The molding material for injection mold should preferably consist of a material having excellent toughness and shock-resistance, such as ZrO2 or the like.
[2] Casing Base Body Cleaning Process
[0038] As shown in Figure 9(b), in this process, an ultrasonic cleaning technique is used to clean the surface of the ceramic base body by using a liquid alkaline cleaner. Specifically, the casing base body cleaning process comprises steps of attaching a jig, degreasing (two steps), washing, and drying (steps 911-915). More specifically, in the first degreasing step, the casing base body is immersed into a heated liquid alkaline cleaner to thereby conduct alkaline degreasing (step 912). The liquid alkaline cleaner preferably has a degreasing property, and in this example, a heated NaOH aqueous solution (NaOH 50g/L) is used. In the subsequent second degreasing step, an ultrasonic wave is applied to the liquid alkaline cleaner to further carry out degreasing (step 913). Subsequently, in the washing step, the casing base body is washed by water to remove the alkaline cleaner (step 914), and then, in the drying step, the casing base body is dried in a drying oven (step 915). The drying temperature is preferably at 100°C-120°C.
[3] Metallic Color Thin Film Deposition Process
[0039] As shown in Figure 9(c), in this process, an ion plating technique is used to form a thin film made of a metallic compound on a surface of the ceramic casing base body prepared in the preceding process. Specifically, the ceramic casing base body (casing main body portion, back lid portion and operation buttons, etc.) is placed inside an ion plating apparatus (step 921), and after a vacuum is established inside the apparatus (step 922), an Argon gas is injected into the apparatus (step 923). Then, an electron gun is used to vaporize and energize Ti or the like in a crucible so as to ionize the same (step 924). At this time, a gas such as N2,C2H2, etc. is introduced into the apparatus as a reaction gas (step 925). As a result, a metallic compound such as TiN, TiC, TiCN, etc. is deposited on the surface of the ceramic base body as a thin film. The thickness of the thin film is preferably about 0.01-5.0 µm. Lastly, the casing is cooled down (step 926) and then, the pressure is returned to a normal pressure and the jig is detached (step 927).
Figure 10 is a flowchart for schematically showing a second embodiment of a method for manufacturing a casing of a radio-controlled wristwatch according to the present invention.
Like the first embodiment, this second embodiment of the casing manufacturing method also comprises a casing base body manufacturing process, casing base body cleaning process and metallic color thin film deposition process. However, the second embodiment differs from the first embodiment in that the metallic color thin film deposition process in the second embodiment comprises two processes (see Figure 10).
[1] Casing Base Body Manufacturing Process
[2] Casing Base Body Cleaning Process
[3] Metallic Color Thin Film Deposition Process
[0042] This metallic color thin film deposition process comprises a process for depositing a metallic compound thin film (Figure 10(a)) and a process for depositing an ornamental metal thin film (Figure 10(b)).
As shown in Figure 10(a), an ion plating technique is used to form a thin film made of a metallic compound on a surface of the ceramic casing base body prepared in the preceding process. Specifically, the ceramic casing base body (casing main body portion, back lid portion and operation buttons, etc.) is placed inside an ion plating apparatus (step 1001), and after a vacuum is established inside the apparatus (step 1002), an Ar gas is injected into the apparatus (step 1003). Then, an electron gun is used to vaporize and energize Ti or the like in a crucible so as to ionize the same (step 1004). At this time, a gas such as N2,C2H2, etc. is introduced into the apparatus as a reaction gas (step 1005). As a result, a metallic compound such as TiN, TiC, TiCN, etc. is deposited on the surface of the ceramic base body as a thin film. The thickness of the thin film is preferably about 0.01-5.0 µm. The formed metallic compound thin film will serve as a conductive material in a following wet plating step. Lastly, the casing is cooled down (step 1006) and then, the pressure is returned to a normal pressure and the jig is detached (step 1007). As shown in Figure 10(b), in the process for depositing an ornamental metal, a wet plating technique is used to further form a thin film made of an ornamental metal on a surface of the metallic compound thin film formed in the above process. Specifically, after the steps of attaching a jig (step 1011), degreasing (step 1012) and activating (step 1013), the casing base body formed with the metallic compound thin film is immersed in an electrolytic solution in a plating bath (step 1014). The deposited metal may be a precious metal such as Au, Pd, Pt, etc. As a result, the ornamental metal is deposited as a thin film on the metallic compound thin film over the casing base body surface. The thickness of the ornamental metal thin film is preferably about 0.1-8.0 µm. Subsequently, two cleaning steps (steps 1015, 1016) and a drying step (step 1017) are carried out before the jig is detached and the finished product is removed (step 1018).
[Embodiments of a Radio-controlled Wristwatch of the Present Invention]
[0043] Figure 11 is a schematic cross-sectional view showing a configuration of a radio-controlled wristwatch actually manufactured by applying the present invention. In this drawing, a reference numeral 9 refers to a casing main body, a reference numeral 10 refers to a casing back lid, a reference numeral 11 refers to a sapphire glass fitted into a window of the casing main body, a reference numeral 12 refers to a dial, a reference numeral 13 refers to an hour hand, a reference numeral 14 refers to a minute hand, a reference numeral 15 refers to a second hand, a reference numeral 16 refers to operation buttons and a reference numeral 17 refers to a movement comprising unified watch and antenna units so as to be adapted for radio control. A ceramic is used as the material of the base body constituting the casing main body 9 and the casing back lid 10.
Figures 12(a), 12(b) and 12(c) are a front view, side view and back view, respectively, of an assembled state of a radio-controlled wristwatch actually manufactured by applying the present invention. In these drawings, the shaded areas indicate the portion covered by the thin film formed by TiN ion plating, of which thickness is set at 0.4 µm. The white areas indicate the ceramic part (ceramic color, when it is white). Thus, the outer appearance of the casing main body assumes a combination of gold having a metallic color or metallic luster and white. The outer appearance of the casing back lid assumes the ceramic color (white). If a wristband of the watch, which is referred to in the drawings with a reference numeral 18, is made of a ceramic, a color combination similar to that of the casing main body can be achieved.
In manufacturing the base body constituting the casing main body and the casing back lid, after the mixing process, an injection molding was carried out. And then, the temperature was raised to 600°C for degreasing, followed by sintering conducted at 1,500°C.
[Control Examples]
[0044] In order to conduct a performance test of the radio-controlled wristwatch according to the present invention, control examples were made. The particulars of the material, specification and configuration of the control examples are as follows:
Control Example 1:
Control Example 2:
[0046] A finished product in that a dial, hands, movement (inclusive of an antenna), etc. are contained in a casing comprising a casing main body made of a brass (Bs) of which surface is plated with a gold (Au) and a casing back lid made of a stainless steel (SUS).
Control Example 3:
[0047] A finished product in that a dial, hands, movement (inclusive of an antenna), etc. are contained in a casing comprising a casing main body made of a stainless steel (SUS) and a casing back lid made of a stainless steel (SUS).
Control Example 4:
[0048] A finished product in that a dial, hands, movement (inclusive of an antenna), etc. are contained in a casing comprising a casing main body made of a plastic and a casing back lid made of a plastic.
Control Example 5:
[0049] A finished product in that a dial, hands, movement (inclusive of an antenna), etc. are contained in a casing comprising a casing main body made of a ceramic and a casing back lid made of a ceramic.
Control Example 6:
[0050] A finished product in that a dial, hands, movement (inclusive of an antenna), etc. are contained in a casing comprising a casing main body made of a ceramic and covered with a 0.4 µm thickness film made by ion plating and a casing back lid made of a ceramic and covered with a 0.4 µm thickness film made by ion plating.
Control Example 7:
[0051] A finished product in that a dial, hands, movement (inclusive of an antenna), etc. are contained in a casing comprising: a casing main body made of a ceramic and covered by a two-layer film having a 0.4 µm thickness lower layer made by ion plating and a 1 µm thickness upper layer made by partial gold (Au) plating; and a casing back lid made of a ceramic and covered with a 0.4 µm thickness film made by ion plating.
Control Example 8:
[0052] A finished product in that a dial, hands, movement (inclusive of an antenna), etc. are contained in a casing comprising: a casing main body made of a ceramic and covered by a two-layer film having a 0.4 µm thickness lower layer made by ion plating and a 1 µm thickness upper layer made by partial gold (Au) plating; and a casing back lid consisting of a glass plate fitted into a an annular frame made of a stainless steel.
[Test Method]
[0054] As shown in Figure 13, the above control examples are placed inside a shielded box 19 (which can shut out the outside electromagnetic wave) one at a time, and a electric field strength of a radio wave time signal of 40 KHz from a radio wave time signal generator 20 is varied to determine the value of electric field strength when each of the control examples detects the radio wave time signal so that the electric field strength value indicates the radio wave receiving ability of the control examples. Thus, a smaller value of the electric field indicates a higher radio wave receiving ability (or more sensitive). Figure 13(a) is a plan view showing the inside arrangement and Figure 13(b) is an elevational view showing the inside arrangement, in which a reference numeral 21 refers to an antenna, a reference numeral 22 refers to a table on which the tested objects are placed, and a reference numeral 23 refers to tested objects (tested watches).
[Test Results]
[0055]
| Tested Object | Electric Field Strength (dB µV/m) |
| Control Example 1 | 40 |
| Control Example 2 | 54 |
| Control Example 3 | 63 |
| Control Example 4 | 40 |
| Control Example 5 | 40 |
| Control Example 6 | 40 |
| Control Example 7 | 40 |
| Control Example 8 | 44 |
[Conclusion]
[0056] Control Examples 2 and 3 are considered inappropriate. Control Examples 4, 5, 6, 7 provided the same value as Control Example 1 which contained only the movement. It should be noted that Control Examples 6, 7 presented the same value as Control Example 1 even though they assumed a metallic color appearance. Thus, it was confirmed that Control Examples 6, 7 are such products as not deteriorating the radio wave receiving ability while offering an ornamental value compatible with a general luxury watches. As to Control Example 8, in which the back lid comprises a stainless steel ring forming an outer frame into which a glass plate is fitted, it was confirmed that there was no problem in the radio wave reception, which can be attributed to the radio wave transmissive property of the glass.
Industrial Applicability
[0057] As may be apparent from the above description, according to the present invention, it is possible to provide a casing of a radio-controlled wristwatch that is suitable for implementing a radio-controlled wristwatch having a luxurious appearance.
1. A casing of a radio-controlled wristwatch, comprising:
a casing base body through which a radio wave can transmit; and
a thin film covering all or part of an exterior surface of the casing base body and having a surface assuming a metallic color.
2. A casing of a radio-controlled wristwatch according to claim 1, wherein the casing
base body comprises a casing main body portion and a back lid portion, all or a substantial
part of the casing main body portion and/or all or a substantial part of the back
lid portion being made of a material having a radio wave transmissive property.
3. A casing of a radio-controlled wristwatch according to claim 2, wherein the material
having a radio wave transmissive property consists of a ceramic or glass.
4. A casing of a radio-controlled wristwatch according to claim 3, wherein the ceramic
consists of ZrO2.
5. A casing of a radio-controlled wristwatch according to any one of claims 1-4, wherein
the thin film having a surface assuming a metallic color comprises a metal or metallic
compound.
6. A casing of a radio-controlled wristwatch according to claim 5, wherein a thickness
of the metal or metallic compound is 0.01-5.0 µm.
7. A casing of a radio-controlled wristwatch according to claim 5 or claim 6, wherein
the metal consists of Au, Ag, Pd, Pt, Rh, Ti, Ta, Cr, Al, Ni, Cu or an alloy thereof,
and the metallic compound consists of TiN, TiC, TiO, TiCN, CrN or TaC, with or without
Au, Ag, Rh, Pd or Pt being added thereto.
8. A casing of a radio-controlled wristwatch according to any one of claims 1-4, wherein
the thin film having a surface assuming a metallic color has a two-layer structure
comprising a lower layer consisting of a metal or a metallic compound and an upper
layer consisting of an ornamental metal.
9. A casing of a radio-controlled wristwatch according to claim 8, wherein the lower
layer consisting of a metal or a metallic compound has a thickness of 0.01-5.0 µm
and the upper layer consisting of an ornamental metal has a thickness of 0.1-8.0 µm.
10. A casing of a radio-controlled wristwatch according to claim 8 or claim 9, wherein
in a case that the lower layer consists of a metal, the metal is Au, Ag, Pd, Pt, Rh,
Ti, Ta, Cr, Al, Ni, Cu or an alloy thereof while in the case that the lower layer
consists of a metallic compound, the metallic compound is TiN, TiC, TiO, TiCN, CrN
or TaC with or without Au, Ag, Rh, Pd or Pt being added thereto, and the upper layer
consisting of an ornamental metal consists of Pt, Pd, Ag, Rh, Cr or Au.
11. A method for manufacturing a casing of a radio-controlled wristwatch, comprising a
step of forming a thin film of a metallic compound on all or part of an exterior surface
of a radio wave transmissive casing base body by using a PVD technique or CVD technique.
12. A method for manufacturing a casing of a radio-controlled wristwatch, comprising a
step of using an ion plating technique to deposit a thin film consisting of a metallic
compound on all or part of an exterior surface of a radio wave transmissive casing
base body using a ceramic as its material.
13. A method for manufacturing a casing of a radio-controlled wristwatch according to
claim 12, the ceramic used as the material of the casing consists of ZrO2.
14. A method for manufacturing a casing of a radio-controlled wristwatch according to
any one of claims 11-13, a thickness of the thin film of a metallic compound is 0.01-5.0
µm.
15. A method for manufacturing a casing of a radio-controlled wristwatch according to
any one of claims 11-13, wherein the metallic compound is TiN, TiC, TiO, TiCN, CrN
or TaC with or without Au, Ag, Rh, Pd or Pt being added thereto.
16. A method for manufacturing a casing of a radio-controlled wristwatch, comprising the
steps of:
using a PVD technique or CVD technique to form a thin film layer consisting of a metallic compound on all or part of an exterior surface of a radio wave transmissive casing base body, and subsequently using a wet plating technique to form an thin film layer of an ornamental metal on the metallic compound film layer.
17. A method for manufacturing a casing of a radio-controlled wristwatch, comprising the
steps of:
using an ion plating technique to form a thin film consisting of a metallic compound on all or part of an exterior surface of a radio wave transmissive casing base body using a ceramic as its material, and subsequently using a wet plating to form a thin film of an ornamental metal on the metallic compound film layer.
18. A method for manufacturing a casing of a radio-controlled wristwatch according to
claim 17, wherein the ceramic used as the material of the casing consists of ZrO2.
19. A method for manufacturing a casing of a radio-controlled wristwatch according to
any one of claims 16-18, wherein a thickness of the metallic compound thin film is
0.01-5.0 µm and a thickness of the ornamental metal thin film is 0.1-8.0 µm.
20. A method for manufacturing a casing of a radio-controlled wristwatch according to
any one of claims 16-18, wherein the metallic compound is TiN, TiC, TiO, TiCN, CrN
or TaC with or without Au, Ag, Rh, Pd or Pt being added thereto, and the ornamental
metal is Pt, Pd, Ag, Rh, Cr or Au.
21. A radio-controlled wristwatch with a built-in antenna, comprising a watch unit and
an antenna unit contained in a common casing, the antenna unit being adapted to receive
a radio wave time signal through the casing,
wherein a casing according to any one of claims 1-10 is used as the casing.
wherein a casing according to any one of claims 1-10 is used as the casing.
Amended claims under Art. 19.1 PCT
1. A radio-controlled wristwatch having a wristwatch casing and a movement with a built-in
antenna, the movement being contained in the casing, wherein:
the wristwatch casing comprises a casing main body portion and a back lid portion;
a ceramic is used as a material of a base body of the casing main body portion, and a ceramic or glass is used as a material of a base body of the back lid portion; and
a thin film of a metal or metallic compound is deposited on all or a substantial part of an exterior surface of the base body of the casing main body portion with a film thickness of 0.01-5.0 µm by using an ion plating technique.
2. A radio-controlled wristwatch according to claim 1, wherein the metal constituting
the thin film consists of Au, Ag, Pd, Pt, Rh, Ti, Ta, Cr, Al, Ni, Cu or an alloy thereof.
3. A radio-controlled wristwatch according to claim 2, wherein the metallic compound
constituting the thin film consists of TiN, TiC, TiO, TiCN, CrN or TaC, with or without
Au, Ag, Rh, Pd or Pt being added thereto.
4. A radio-controlled wristwatch according to claim 2 or claim 3, wherein the ceramic
used as the material of the base body of the casing main body portion consists of
a zirconia.
5. A radio-controlled wristwatch having a wristwatch casing and a movement with a built-in
antenna, the movement being contained in the casing, wherein:
the wristwatch casing comprises a casing main body portion and a back lid portion;
a ceramic is used as a material of a base body of the casing main body portion, and a ceramic or glass is used as a material of a base body of the back lid portion; and
a thin film is deposited on all or a substantial part of an exterior surface of the base body of the casing main body portion, the thin film having a two-layer structure comprising a lower layer consisting of a metal or a metallic compound and deposited by means of an ion plating technique and an upper layer consisting of an ornamental metal and deposited by means of a wet plating technique, and the lower layer having a thickness of 0.01-5.0 µm and the upper layer having a thickness of 0.1-8.0 µm.
6. A radio-controlled wristwatch according to claim 5, wherein the metal constituting
the lower layer consists of Au, Ag, Pd, Pt, Rh, Ti, Ta, Cr, Al, Ni, Cu or an alloy
thereof.
7. A radio-controlled wristwatch according to claim 5, wherein the metallic compound
constituting the lower layer consists of TiN, TiC, TiO, TiCN, CrN or TaC with or without
Au, Ag, Rh, Pd or Pt being added thereto.
8. A radio-controlled wristwatch according to claim 5, wherein the ornamental metal
constituting the upper layer consists of Pt, Pd, Ag, Rh, Cr or Au.
9. A radio-controlled wristwatch according to any one of claims 6-8, wherein the ceramic
used as the material of the base body of the casing main body portion consists of
a zirconia.
Statement under Art. 19.1 PCT
In claims 1 and 2, it is made clear that a radio-controlled wristwatch in that a movement with a built-in antenna is accommodated in a wristwatch casing is a prerequisite for the present invention.
The first reference cited (Japanese Patent Application Laid-Open Publication No. 60-137882) has disclosed a wristwatch casing having a base body consisting of a zirconia ceramic covered by a thin film mainly consisting of a titanium nitride. The fourth, fifth and sixth references cited (Japanese Patent Application Laid-Open Publication No. 62-238375, Japanese Patent Application Laid-Open Publication No.62-245182,and Japanese Patent Application Laid-Open Publication No.60-50177) have disclosed a wristwatch casing having a plastic base body on which a plating thin film having a single or double-layer structure is deposited. However, none of these references have disclosed or indicated to accommodate a movement with a built-in antenna in the wristwatch casing to thereby constitute a radio-controlled wristwatch. Further, when the base body consists of a plastic, the strength is insufficiently weak, and the appearance lacks a metallic air and thus cannot offer a sufficient luxurious feeling.
According to the structure defined in the claims, the present invention can provide a wristwatch having a luxurious metallic appearance and a sufficient strength as well as a high radio wave receiving sensitivity.