HK1081673B

HK1081673B - Radio-controlled clock/watch

Info

Publication number: HK1081673B
Application number: HK06101787.9A
Authority: HK
Inventors: 伊藤静枝; 小林稔; 伊原隆史; 高桥重之
Original assignee: 西铁城时计株式会社
Priority date: 2002-12-27
Filing date: 2003-12-26
Publication date: 2010-04-16

Description

Radio controlled watch

Technical Field

The present invention relates to a radio controlled timepiece for receiving a predetermined radio wave including time information and displaying a time. More particularly, the present invention relates to a case structure of a radio controlled watch for improving radio wave receiving performance and antimagnetic performance against external magnetism in the case of using a general metal case.

Background

There is known an electronic timepiece for receiving a standard radio wave, i.e., a radio-controlled timepiece, which is capable of receiving a standard radio wave (a carrier wave) including time information and acquiring the time information from the radio wave, thereby obtaining an accurate time. The radio wave including the time information has a frequency that varies with each country. For example, in japan, standard radio waves of 40kHz and 60kHz are emitted under the management of the ministry of foreign affairs and communications (MIC) and the postal service.

Fig. 26 schematically shows a block diagram of the functions of such a radio control table. The radio-controlled watch is constituted by an antenna 1, a radio-controlled watch receiver 2, a CPU3, a display driving section 4, an input device 5, and the like. Further, an hour hand, minute hand, and second, or a display portion composed of liquid crystal or the like (not shown) is included.

In the radio-controlled watch, a radio wave including time information is first received by the antenna 1. The receiver 2 of the radio-controlled watch amplifies and detects the radio waves received by the antenna 1, and acquires and outputs time information from the radio waves. The CPU3 outputs the current time based on the time information output from the receiver 2 of the radio-controlled watch. The display driving section 4 causes the display section to display a current time based on the current time data output from the CPU 3. For example, if operation information such as a reset to the CPU3 is input, the input device 5 is used.

Time information (time code) included in a radio wave is a pulse signal having a period of 60 seconds and varying depending on each country. In japan, one pulse has a width of 200, 500, or 800 milliseconds per second. By the combination of these pulses, time information is obtained within 60 seconds.

The CPU3 reads the width of the pulse per second from the received pulse signal, thereby obtaining time information (a current time). The CPU corrects the time displayed in the display section by the display driving section 4 based on the obtained time information. Therefore, the radio-controlled watch can always display an accurate time by correcting the displayed time every predetermined time interval based on the received time information.

A watch, which is accommodated in a watch case serving as an antenna case, an antenna, a receiver of a radio controlled watch, a CPU, a display driving section and a display section, has been provided as the radio controlled watch. A non-conductive material such as a synthetic resin or ceramic has been mainly used for the material of the watch case so as to receive a radio wave through the antenna.

Specifically, if the antenna is housed in a case formed of a conductive material such as metal, a magnetic flux generated in the vicinity of the antenna is absorbed into the conductive material, and thus a resonance phenomenon is prevented. For this reason, the receiving function of the antenna is significantly impaired, so that the antenna cannot receive a standard radio wave.

However, in order to avoid the failure of the antenna reception, if a watch case formed of a synthetic resin is used, the deterioration resistance or chemical resistance of the watch case is reduced. In addition, the high-grade feel and fine appearance required as a pocket watch would also be impaired. For this reason, a radio controlled watch has been proposed which uses a metal as the case.

Fig. 27 is a sectional view showing an example of the structure of a radio control watch using a metal as a part of a watch case.

A watch case 10 is schematically composed of a case 11, a back cover 12 and a windshield 13. A movement 14 is disposed within the housing and a belt (not shown) is attached to the movement by known means. Similarly, a clock panel 15 and hands 16 serving as a time display section are provided above the movement 14 by a known method.

An antenna mast 17 of a magnetic long-wave antenna is provided, which is positioned below the movement 14 and above the back cover 12. The antenna rod 17 includes a core member 18 formed of a ferromagnetic material and a coil 20 wound around the core member 18, and is fixed to an upper surface of a holder formed of a synthetic resin.

The movement 14 includes the radio-controlled watch receiver 2, the CPU3, and the display drive section 4 shown in fig. 26 described above, and is electrically conducted with the antenna 17 through a conductor 21.

Therefore, based on a standard radio wave received by the antenna stick 17, the CPU of the movement 14 operates a gear mechanism (not shown) in the display drive section, thereby driving the gear mechanism so as to always correct the position of the pointer 16 in the display section. A vertical direction indicates the upper and lower portions in fig. 27.

The watch case 11 is formed of an electrically conductive material that is not hollow, i.e., a solid metal, such as solid stainless steel. A windshield 13 formed of glass of a non-conductive material is fixed to the uppermost portion of the case band 11 by a known method such as adhesion. The clock panel 15 is formed of a non-conductive synthetic resin, ceramic, or the like. The back cover 12 is composed of an annular edge frame 22 formed of stainless steel, which is fixed to the case band 11, and a glass 23 fixed into the edge frame. Thus, a non-conductive material can be seen in the watch on the upper and lower surfaces of the case, while the side surface portion of the case is composed of a metal. Therefore, there is an advantage in that: it is possible to prevent the high-class feeling and the fine appearance of the accessories from being impaired (see japanese laid-open patent publication No. 2001-33571).

However, the table shown in fig. 27 has no great problem in radio wave reception performance for portable use. The glass 23 is fixed to the edge frame 22 of the back cover 12. For this reason, there is a problem in that the glass 23 is broken if an impact is applied, for example, the watch is dropped.

Further, the back cover 12 is disposed in close contact with the arm. Therefore, the glass 23 may slip out of the edge frame 22 due to sweat or the like in long-term use. Furthermore, there is also the possibility of: sweat, water, dust, etc. may enter into the movement (the antenna 1, the radio-controlled watch receiver 2, the CPU3, the display drive section 4, etc.) in the watch, causing the watch function to drop significantly.

Further, a glass 23 is provided inside the back cover 12. For this reason, there is a problem in that the number of parts increases, the man-hour (labor) of assembly also increases, and the cost increases. In addition, a non-metallic member is used for an outer member. Therefore, the watch lacks the feeling of weight and thickness, and also has deficiencies in high-class feeling and appearance quality.

In addition, the watch shown in fig. 27 uses a metal for the case band. For this reason, it is impossible to eliminate the disadvantage that the antenna is disposed close to a metal member. The receiving performance of the antenna rod of the watch is thus reduced by about 40% compared to a watch case in which the whole of the case is made of a non-conductive material. In an environment where standard radio wave reception is difficult, for example, in a place far from a standard radio wave transmitting station, in many cases, a radio-controlled watch cannot receive the standard radio wave.

On the other hand, in a watch in which a hand is driven by a motor, the driving operation of the hand is generally affected by external magnetism, so that the accuracy of the watch is impaired in some cases. For this reason, a magnetism preventive plate that blocks the external magnetism is provided in the case, thereby maintaining the accuracy of the watch.

Fig. 28 is a sectional view showing a watch structure in which a magnetism preventing plate for preventing the influence of external magnetism as described above is provided between a middle frame for holding a movement and a back cover.

In this structure, a middle frame 6 for fixing the movement 4 is provided in the wristwatch case 2, and an upward U-shaped antimagnetic plate 10 is attached to the back cover 8 side of the middle frame 6, thereby surrounding the movement 4 (see japanese utility model registration No. 2505967).

The antimagnetic plate 10 is fixed to a module with a screw or a slope as described above, or is inserted between the core 8a of the back cover 8 and the middle frame 6, and is thus fixed, or is bonded and fixed to the inner surface of the back cover 8 with an adhesive, and is fixed with a fixing structure corresponding to a space in the case, and a structure of the module, etc.

In a radio-controlled table having the same structure as that of a general table for driving hands, likewise, a countermeasure against the magnetic resistance is required to maintain the accuracy of the table. However, the radio-controlled watch is used to receive a standard radio wave (carrier wave) including time information and to take out the time information from the radio wave, thereby obtaining and displaying an accurate time. When the movement is surrounded by the antimagnetic plate so as to block the external magnetism, there is a possibility that the reception performance may be degraded. For this reason, the antimagnetic plate may not be used in the radio-controlled watch.

In view of the problems of the conventional art, it is an object of the present invention to provide a watch case of a radio controlled watch capable of receiving radio waves including predetermined information such as time information, not hindering portability even if an ordinary metal watch case is used, improving stable waterproof quality and appearance quality with a high quality feeling, and increasing variations of the same design as the design of an ordinary watch.

Further, it is an object of the present invention to provide a radio-controlled watch capable of receiving radio waves including predetermined information such as time information even if a wristwatch case having a magnetism-preventing plate provided in the wristwatch case is used, and maintaining a predetermined accuracy of time in some environments having an external magnetism.

Disclosure of Invention

In order to solve the above problems and achieve the objects in the above conventional art, the present invention is particularly proposed, and a radio-controlled watch according to the present invention includes:

an antenna for receiving a radio wave including time information;

a watch device for causing the display section to display time information such as the current time of a radio wave received by the antenna;

a case for housing the antenna and the watch device; and

at least one non-magnetic member fixed to an inner surface of the case has a resistivity set to 7.0 [ mu ] omega-cm or less.

Further, in the radio-controlled watch of the present invention, the watch case is formed of at least one material selected from the group consisting of: titanium, titanium alloys, stainless steel, tungsten carbide and tantalum carbide, and

the non-magnetic member is fixed to an inner surface of the case.

In addition, in the radio-controlled watch of the present invention, the watch case includes a case band,

the case band is formed of at least one material selected from the following materials: titanium, titanium alloys, stainless steel, tungsten carbide and tantalum carbide, and

the non-magnetic member is fixed to an inner surface of the case band.

Further, in the radio controlled watch of the present invention, the wristwatch case includes a case band and a back cover attached and fixed to the case band,

the back cover is formed of at least one material selected from the following materials: titanium, titanium alloys, stainless steel, tungsten carbide and tantalum carbide, and

the non-magnetic member is fixed to an inner surface of the back cover.

Thus, a non-magnetic member having a resistivity of 7.0 μ Ω -cm or less is provided in a case housing the antenna and the watch device. Therefore, it is possible to reduce interference of a resonance phenomenon in the vicinity of the antenna caused by the metal material. Therefore, sufficient reception sensitivity can be obtained also in the metal wristwatch case.

By using a non-magnetic member having a resistivity of 7.0 mu omega-cm or less, since a non-magnetic member is fixed in a watch case, for example, at the inner surfaces of a case body and a back cover of a radio controlled watch, a metal having excellent appearance quality, for example, titanium alloy, stainless steel or tantalum carbide, which has a low reception sensitivity, a low frequency selectivity and a high resistivity like the watch case, for example, the case body and the back cover, can be used without sacrificing the reception sensitivity. Therefore, the function of the case mechanism and the appearance can be improved.

Further, in the radio-controlled watch of the present invention, the non-magnetic member is formed of at least one material selected from the following materials: gold, silver, copper, brass, aluminum, magnesium, zinc, and alloys thereof.

Further, in the radio-controlled watch of the present invention, the non-magnetic member is formed by bonding at least two materials selected from the following materials: gold, silver, copper, brass, aluminum, magnesium, and alloys thereof.

Gold, silver, copper, brass, aluminum, magnesium, or alloys thereof are a metal having a resistivity of 7.0 μ Ω -cm or less. By using such a metal as a nonmagnetic member fixed to the inner surface of the case band or the back cover of the watch case, the reception sensitivity and the frequency selectivity can be improved so as to reduce the interference of the resonance phenomenon in the vicinity of the antenna caused by the metal material. Therefore, sufficient reception sensitivity can be obtained also in the metal wristwatch case.

Further, in the radio-controlled watch of the present invention, a resin member is provided in close contact with the inner surface of the non-magnetic member.

With such a structure, the antenna can be prevented from being damaged due to contact with the nonmagnetic member, resulting in deterioration of the reception state.

Further, in the radio-controlled watch of the present invention, the antenna is constituted by a magnetic core and a coil wound around the magnetic core by a plurality of turns, and

the non-magnetic member is disposed at a position of the case band, wherein the antenna protrudes in parallel on the inner surface of the case band along at least one plane including the axis of the magnetic core member.

the nonmagnetic member is provided at a position of the back cover, wherein the antenna protrudes in parallel on the inner surface of the watch case along at least one plane including the axis of the magnetic core member.

the nonmagnetic member is provided at a position on the inner surface of the case opposite to at least one end in the axial direction of the antenna.

The non-magnetic member is disposed at such a position. Therefore, the non-magnetic member is positioned in the vicinity of the antenna, and thus, it is possible to reduce interference of a resonance phenomenon in the vicinity of the antenna caused by the metal material. Therefore, sufficient reception sensitivity can be obtained also in the metal wristwatch case.

Further, in the radio-controlled watch of the present invention, the watch case is composed of a cladding material obtained by bonding a non-magnetic member in pressure contact with at least one material selected from titanium, titanium alloys and stainless steel.

the watch case is composed of a clad material obtained by bonding a non-magnetic member in pressure contact with at least one material selected from titanium, titanium alloys, and stainless steel.

the back cover is composed of a clad material obtained by bonding a non-magnetic member in pressure contact with at least one material selected from titanium, titanium alloy and stainless steel.

With such a structure, it is also possible to integrally bond and fix the nonmagnetic member to the case band and the back cover while the case is in the material stage, and then, adjust the shape thereof. Therefore, it can correspond to a complicated shape of the wristwatch case, and moreover, the manufacturing process is simplified, thereby reducing the cost.

Further, in the radio controlled watch of the present invention, the non-magnetic member is fixed to the watch case by at least one method such as press-fitting, caulking, welding, brazing, and adhesive.

Further, in the radio-controlled watch of the present invention, the watch case includes a case band, and

the non-magnetic member is fixed to the case band by at least one method such as press-fitting, caulking, welding, brazing, and adhesive.

Further, in the radio-controlled watch of the invention, the wristwatch case includes a case band and a back cover attached and fixed to the case band, and

the non-magnetic member is fixed to the back cover by at least one method such as press-fitting, caulking, welding, brazing, and an adhesive.

With such a structure, the non-magnetic member can be easily fixed to the inner surfaces of the watch case, for example, the inner surfaces of the case band and the back cover.

Further, in the radio controlled watch of the present invention, the non-magnetic member fixed to the watch case is formed by a method such as a wet coating method or a metal spraying method.

the non-magnetic member fixed to the case band is formed by a method such as a wet coating method or a metal spraying method.

the non-magnetic member fixed to the back cover is formed by a method such as a wet coating method or a metal spraying method.

With such a structure, the non-magnetic member can be easily fixed to the inner surface of the case, for example, to the inner surfaces of the case band and the back cover by a wet coating method or a metal spraying method. Therefore, it is possible to correspond to a complicated shape of the wristwatch case, and further, to simplify the manufacturing process, thereby reducing the cost.

Further, in the radio controlled watch of the present invention, the thickness of the non-magnetic member is 50 μm to 2000 μm.

If the non-magnetic member has a thickness in such a range, the antenna has a high gain, high reception sensitivity and excellent frequency sensitivity. Further, such a thickness is optimum in view of the distance between the case band or the back cover and the movement or the antenna, or in view of the convenience of handling the non-magnetic member in manufacturing and assembling.

Further, the radio-controlled watch according to the present invention includes:

an antenna for receiving a radio wave including time information;

a watch device for causing the display section to display time information such as the current time of a radio wave received by the antenna; and

a case for housing the antenna and the watch device;

wherein the watch case has at least one portion constituted by a non-magnetic member having a resistivity of 7.0 [ mu ] omega-cm or less, and

one surface of the watch case is subjected to surface polishing.

Further, in the radio controlled watch of the present invention, the case comprises a case band, a back cover and a bezel,

at least one of the case band, the back cover and the bezel is formed of a non-magnetic member, an

The watch case other than the watch case composed of the non-magnetic member is formed of at least one material selected from the group consisting of: titanium, titanium alloys, stainless steel, tungsten carbide, tantalum carbide, and resins.

With such a structure, a part of the wristwatch case, for example, a part of the case band, the back cover, the bezel, etc., or at least one of them, is formed of a non-magnetic member having a resistivity of 7.0 μ Ω -cm or less. Therefore, interference of the resonance phenomenon in the vicinity of the antenna caused by the metal material can be reduced by the nonmagnetic material. Therefore, sufficient reception sensitivity can be obtained also in the metal wristwatch case.

By using a non-magnetic member having a resistivity of 7.0 μ Ω -cm or less for a part of a case of a radio controlled watch, for example, a part of a case body, a back cover, a bezel, or the like, or at least one of them, a metal having excellent appearance quality such as titanium, a titanium alloy, stainless steel, or tantalum carbide having low reception sensitivity, low frequency selectivity, and high resistivity can be used as a case body part other than a case body part formed of the non-magnetic member without sacrificing the reception sensitivity. Thus, the function of the watch case in terms of mechanics and appearance can be improved.

Further, surface polishing is performed on the surface of the case portion formed of the non-magnetic member. Therefore, it is possible to design and manufacture a watch case having corrosion resistance, heat resistance, mechanical strength, etc., and having a color feeling such as a metallic color, which has a high-class feeling and high appearance quality, for example, a case band, a back cover, a bezel, etc., in the same manner as a general watch which is not a radio-controlled watch. Thus, variations in the design of the watch case in a radio controlled watch can be improved to be comparable to a normal watch.

Further, in the radio-controlled watch of the present invention, the non-magnetic member is composed of at least one material selected from the following materials: gold, silver, copper, brass, aluminum, magnesium, zinc, and alloys thereof.

Gold, silver, copper, brass, aluminum, magnesium, or alloys thereof are a metal having a resistivity of 7.0 μ Ω -cm or less. By using such a metal as a non-magnetic member of a part of the watch case, for example, a part of the case band, the back cover, the bezel, or the like, or at least one of them, it is possible to improve the reception sensitivity and the frequency selectivity so as to reduce interference of the resonance phenomenon in the vicinity of the antenna caused by the metal material. Therefore, sufficient reception sensitivity can be obtained also in the metal wristwatch case.

Further, in the radio-controlled watch of the present invention, the antenna is constituted by a core member and a coil wound around the core member by a plurality of turns, and

a part of the case on which the antenna projects parallel along at least one plane including the axis of the core, or a portion on which the projecting part of the case projects, the part of the case or said portion being constituted by a non-magnetic element.

a part of the case opposite to at least one end in the axial direction of the antenna, or a part thereof opposite to a part of the case opposite to one end in the axial direction, the part of the case or the part thereof being constituted by a non-magnetic member.

Further, in the radio-controlled watch of the present invention, the surface polishing is constituted by at least one surface polishing process selected from the following forms: a mirror-polished surface, a matte-polished surface, a hairline pattern, a pattern, and a symbol.

Thus, the surface finish is composed of a mirror-finished surface, a matte-finished surface, hair patterns, figures, and symbols. Therefore, it is possible to design and manufacture a watch case having a high-class feeling and high appearance quality, for example, a case band, a back cover, a bezel, and the like in the same manner as a general watch which is not a radio-controlled watch. Thus, variations in the design of the watch case in a radio controlled watch can be improved to be comparable to a normal watch.

In addition, in the radio-controlled watch of the present invention, the surface polishing treatment is constituted by a metal coating film,

the metal coating film is provided by at least one method selected from the following methods: wet coating, evaporative precipitation, ion coating, arc, and cathode sputtering.

Therefore, the surface polishing treatment is constituted by a metal coating film. Therefore, it is possible to design and manufacture a watch case having corrosion resistance, heat resistance, mechanical strength, etc., and having a color feeling such as a metallic color, which has a high-class feeling and high appearance quality, for example, a case band, a back cover, a bezel, etc., in the same manner as a general watch which is not a radio-controlled watch. Thus, variations in the design of the watch case in a radio controlled watch can be improved to be comparable to a normal watch.

Further, such a metal coating film is formed by a wet coating method, an evaporation method, an ion coating method, an arc method, and a cathode sputtering method. Therefore, it can correspond to a complicated shape of the watch case, and therefore, the manufacturing process is simplified, thereby reducing the cost.

Further, in the radio-controlled watch of the present invention, the surface of the non-magnetic member is subjected to a surface polishing treatment.

Therefore, the surface polishing treatment is performed on the surface of the non-magnetic member. Therefore, it is possible to design and manufacture a watch case having corrosion resistance, heat resistance, mechanical strength, etc., and having a color feeling such as a metallic color, which has a high-class feeling and high appearance quality, for example, a case band, a back cover, a bezel, etc., in the same manner as a general watch which is not a radio-controlled watch. Thus, variations in the design of the watch case in a radio controlled watch can be improved to be comparable to a normal watch.

an antenna for receiving a radio wave including time information;

a case for housing the antenna and the watch device,

wherein the watch case is made of metal.

Further, in the radio-controlled timepiece of the invention, the antenna is provided in contact with the inner surface of the case.

Further, in the radio-controlled watch of the present invention, the antenna is disposed away from the inner surface of the case.

Therefore, the wristwatch case is made of metal, and the distance between the antenna and the wristwatch case, that is, the body thickness T1 of the case body of the wristwatch case, the back cover thickness T2 of the back cover of the wristwatch case, the gap D1 from the inner surface of the wristwatch case to the antenna, and the gap D2 from the inner surface of the back cover to the antenna are set in accordance with the reception sensitivity. Therefore, interference of a resonance phenomenon in the vicinity of the antenna caused by the metal material can be reduced. Therefore, the receiving sensitivity can be improved also in the metal wristwatch case. Therefore, a metal having excellent appearance quality, such as titanium, titanium alloy, stainless steel or tantalum carbide, which has a low reception sensitivity, a low frequency selectivity and a high specific resistance as in a watch case, such as a watch case, a back cover, a bezel, etc., can be used without sacrificing the reception sensitivity. Therefore, the function of the case mechanism and the appearance can be improved.

Further, in the radio-controlled watch of the present invention, the watch case and the antenna are set in such a manner that: the body thickness T1 of the case body of the watch case ranges from 300 μm to 5000 μm.

Further, in the radio-controlled watch of the present invention, the watch case and the antenna are set in such a manner that: the body thickness T1 of the case body of the watch case ranges from 500 μm to 2000 μm.

Therefore, the body thickness T1 of the case band of the wristwatch case is set to 300 μm to 5000 μm. Therefore, it is possible to have a high antenna gain and excellent reception sensitivity while maintaining strength effective for the case and the like.

In particular, the body thickness T1 of the case band of the wristwatch case is set to 500 μm to 2000 μm. Therefore, it is possible to have a high antenna gain and excellent reception sensitivity while maintaining strength effective for the case and the like. Furthermore, a better case is obtained, considering the aspects of appearance, workability, corrosion resistance, etc. of the watch case.

Further, in the radio-controlled watch of the present invention, the watch case and the antenna are set in such a manner that: the gap D1 from the inner surface of the case of the watch case to the antenna is in the range of 0 to 40000 μm.

Further, in the radio-controlled watch of the present invention, the watch case and the antenna are set in such a manner that: the gap D1 from the inner surface of the case of the watch case to the antenna is in the range of 500 μm to 10000 μm.

By setting the positional relationship between the case of the wristwatch case and the antenna, that is, the gap D1 from the inner surface of the case of the wristwatch case to the antenna at 0 to 40000 μm, it is possible to obtain a high antenna gain and excellent reception sensitivity.

By setting the gap D1 from the inner surface of the case of the wristwatch case to the antenna at 500 μm to 10000 μm, in particular, a high antenna gain, an excellent receiving sensitivity, a strength suitable for the wristwatch case, and the like can be maintained. Furthermore, a better case can be obtained, considering aspects of the appearance, workability, corrosion resistance, etc. of the watch case.

Further, in the radio-controlled watch of the present invention, the watch case and the antenna are set to: the back cover thickness T2 of the back cover of the watch case is in the range of 100 μm to 5000 μm.

Further, in the radio-controlled watch of the present invention, the watch case and the antenna are set to: the back cover thickness T2 of the back cover of the watch case is in the range of 300 μm to 2000 μm.

By setting the back cover thickness T2 of the back cover of the wristwatch case in the range of 100 μm to 5000 μm, a high antenna gain, an excellent receiving sensitivity, a strength suitable for the wristwatch case, and the like can be maintained.

By setting the back cover thickness T2 of the back cover of the wristwatch case in the range of 300 μm to 2000 μm, in particular, a high antenna gain, an excellent receiving sensitivity, a strength suitable for the wristwatch case, and the like can be maintained. Furthermore, a better back cover of the watch case is obtained, taking into account the aspects of appearance, workability, corrosion resistance, etc. of the watch case.

Further, in the radio-controlled watch of the present invention, the watch case and the antenna are set to: the gap D2 from the inner surface of the back cover of the watch case to the antenna is in the range of 0 to 5000 μm.

Further, in the radio-controlled watch of the present invention, the watch case and the antenna are set to: the gap D2 from the inner surface of the back cover of the watch case to the antenna is in the range of 100 μm to 700 μm.

By setting the positional relationship between the back cover of the case and the antenna, that is, the gap D2 from the inner surface of the back cover of the case to the antenna at 0 to 50000 μm, therefore, a high antenna gain and an excellent receiving sensitivity, a strength suitable for the case, and the like can be obtained.

By setting the gap D2 from the inner surface of the back cover of the watch case to the antenna at 100 μm to 700 μm, in particular, a high antenna gain, an excellent receiving sensitivity, a strength suitable for the watch case, and the like can be maintained. Furthermore, a better back cover of the watch case is obtained, taking into account the aspects of appearance, workability, corrosion resistance, etc. of the watch case.

In the radio-controlled watch of the present invention, the case body of the watch case is formed of at least one material selected from the group consisting of: titanium, titanium alloys, stainless steel, tungsten carbide, and tantalum carbide.

In the radio-controlled watch of the present invention, the back cover of the watch case is formed of at least one material selected from the group consisting of: titanium, titanium alloys, stainless steel, tungsten carbide, and tantalum carbide.

By setting the distance between the antenna and the wristwatch case, that is, the body thickness T1 of the case body of the wristwatch case, the back cover thickness T2 of the back cover of the wristwatch case, the gap D1 from the inner surface of the wristwatch case to the antenna, and the gap D2 from the inner surface of the back cover to the antenna according to the above-described reception sensitivity, the interference of the resonance phenomenon in the vicinity of the antenna caused by the metal material can be reduced.

Therefore, a metal having excellent appearance quality such as titanium, a titanium alloy, stainless steel, or tantalum carbide having low reception sensitivity, low frequency selectivity, and high resistivity can be used as the watch case, for example, a watch case, a back cover, a bezel, or the like, without sacrificing reception sensitivity. Thus, the function of the watch case in terms of mechanics and appearance can be improved.

Further, in the radio-controlled watch of the present invention, the case band of the watch case is formed of at least one material selected from the following materials: gold, silver, copper, brass, aluminum, magnesium, zinc, and alloys thereof.

Further, in the radio-controlled watch of the present invention, the case band of the watch case is formed by bonding at least two materials selected from the following materials: gold, silver, copper, brass, aluminum, magnesium, zinc, and alloys thereof.

Further, in the radio-controlled watch of the present invention, the back cover of the watch case is formed of at least one material selected from the following materials: gold, silver, copper, brass, aluminum, magnesium, zinc, and alloys thereof.

Further, in the radio-controlled watch of the present invention, the back cover of the watch case is formed by bonding at least two materials selected from the following materials: gold, silver, copper, brass, aluminum, magnesium, zinc, and alloys thereof.

Gold, silver, copper, brass, aluminum, magnesium, or alloys thereof are a metal having a resistivity of 7.0 μ Ω -cm or less. By using such a metal as a case, for example, a case band, a back cover, a bezel, and the like, it is possible to improve the reception sensitivity and the frequency selectivity so as to reduce interference of a resonance phenomenon in the vicinity of an antenna caused by a metal material. Therefore, sufficient reception sensitivity can be obtained also in the metal wristwatch case.

Further, in the radio-controlled watch of the present invention, the case band of the watch case is formed of a hard metal.

Further, in the radio-controlled watch of the present invention, the back cover of the watch case is formed of a hard metal.

By constructing the wristwatch case, for example, a case band, a back cover, a bezel, etc., of hard metal, the receiving sensitivity can be improved also in the wristwatch case using metal. Further, abrasion and damage can be prevented, and mechanical strength and the like can be improved.

Further, in the radio-controlled watch of the present invention, at least one of the case body and the back cover of the watch case is subjected to a surface treatment and/or a hardening treatment.

Therefore, a surface treatment and/or a hardening treatment is performed on the case band or the back cover in the case. Therefore, it is possible to design and manufacture a watch case having corrosion resistance, heat resistance, mechanical strength, etc., and having a color feeling such as a metallic color, which has a high-class feeling and high appearance quality, for example, a case band, a back cover, a bezel, etc., in the same manner as a general watch which is not a radio-controlled watch. Thus, variations in the design of the watch case in a radio controlled watch can be improved to be comparable to a normal watch.

Further, in the radio-controlled watch of the present invention, the inner surface of the case band of the watch case and the outer side surface of the antenna are disposed substantially in parallel to each other as a plane.

Further, in the radio-controlled timepiece of the invention, one end faces of both ends in the axial direction of the antenna are disposed substantially parallel to the inner face of the back cover of the case.

Further, in the radio-controlled watch of the present invention, the outer side surface of the antenna is disposed substantially perpendicular to the inner surface of the back cover of the watch case.

Specifically, even if the antenna is disposed in a vertically erected state (in the vertical direction) within the watch case, it is possible to reduce the interference of the resonance phenomenon in the vicinity of the antenna caused by the metal material by setting the distance between the antenna and the watch case, that is, the body thickness T1 of the case of the watch case, the back cover thickness T2 of the back cover of the watch case, the gap D1 from the inner surface of the case to the antenna, and the gap D2 from the inner surface of the back cover to the antenna, in accordance with the reception sensitivity as described above.

Further, in the radio-controlled watch of the present invention, the inner surface of the back cover of the watch case and the outer side surface of the antenna are arranged substantially parallel to each other.

Further, in the radio-controlled watch of the present invention, the inner surface of the case band of the watch case and the outer side surface of the antenna are arranged substantially parallel to each other as a plane.

Specifically, even if the antenna is disposed so as to lie flat in the horizontal direction within the watch case, it is possible to reduce the interference of the resonance phenomenon in the vicinity of the antenna caused by the metal material by setting the distance between the antenna and the watch case, that is, the body thickness T1 of the case of the watch case, the back cover thickness T2 of the back cover of the watch case, the gap D1 from the inner surface of the case to the antenna, and the gap D2 from the inner surface of the back cover to the antenna, in accordance with the reception sensitivity as described above.

Further, in the radio-controlled timepiece of the invention, the back cover of the case is two-dimensionally planar.

When the above portion is not formed on the back cover but the inner surface is made flat so that the back cover has a two-dimensional planar shape, interference of the resonance phenomenon around the antenna can be more reduced and the reception sensitivity can be more improved, as compared with the case in the watch case in which the rising portion is provided.

Further, in the radio-controlled watch of the present invention, at least one nonmagnetic member having a resistivity of 7.0 μ Ω -cm or less is fixed to the inner surface of the watch case.

Thus, a non-magnetic member having a resistivity of 7.0 μ Ω -cm or less is provided on the inner surface of the watch case. Therefore, interference of a resonance phenomenon in the vicinity of the antenna caused by the metal material can be reduced. Therefore, sufficient reception sensitivity can be obtained also in the metal wristwatch case.

By using a non-magnetic member having a resistivity of 7.0 μ Ω -cm or less as the non-magnetic member fixed to the watch case, for example, the inner surfaces of the case and the back cover in the radio-controlled watch, it is possible to use a metal having excellent appearance quality such as titanium, a titanium alloy, stainless steel or tantalum carbide having low reception sensitivity, low frequency selectivity and high resistivity as the watch case, for example, the case, the back cover, without sacrificing the reception sensitivity. Thus, the function of the watch case in terms of mechanics and appearance can be improved.

a part of a watch case to which the antenna projects in parallel along at least one plane including an axis of the magnetic core, or a portion to which the projecting part of the watch case projects, said part or portion being constituted by a non-magnetic element.

a part of the case opposite at least one end in the axial direction of the antenna, or a portion thereof opposite a part of the case opposite the one end in the axial direction, said part or portion being constituted by a non-magnetic member.

The non-magnetic member is disposed at such a position. Therefore, the non-magnetic member is positioned in the vicinity of the antenna, so that interference of a resonance phenomenon in the vicinity of the antenna caused by the metal material can be reduced. Therefore, sufficient reception sensitivity can be obtained also in the metal wristwatch case.

an antenna for receiving a radio wave including time information;

a magnetic shielding plate for shielding external magnetic influence; and

a case for accommodating the antenna, the watch device and the antimagnetic plate;

wherein the antimagnetic plate provided in the case has an opening portion in a portion opposed to the antenna.

Therefore, the antimagnetic plate provided in the case has an opening portion in a portion opposed to the antenna. Therefore, the antenna can receive radio waves through the opening portion without the influence of the antimagnetic plate. Therefore, in the radio-controlled timepiece as well, the timepiece device can be prevented from being affected by external magnetism without degrading the reception characteristics of radio waves. Therefore, accuracy can be improved in the table without affecting the driving operation of the pointer.

an opening portion is provided in a position on the antimagnetic plate, wherein the antenna protrudes in parallel along at least one plane including the axis of the magnetic core member.

an opening portion is provided on the antimagnetic plate in a position opposite to at least one end in the axial direction of the antenna.

The opening portion is provided in a position on the antimagnetic plate, i.e., in a position opposite to the antenna. Therefore, the antenna can receive radio waves through the opening portion without the influence of the antimagnetic plate. Therefore, in the radio-controlled timepiece as well, the timepiece device can be prevented from being affected by external magnetism without degrading the reception characteristics of radio waves. Therefore, accuracy can be improved in the table without affecting the driving operation of the pointer.

Further, in the radio-controlled watch of the present invention, an antenna is provided to be positioned on the outer face of the magnetism preventing plate.

Further, in the radio-controlled watch of the present invention, the antenna has at least a part protruding from the opening portion of the antimagnetic plate and positioned on the inner surface side of the case band of the watch case.

Further, in the radio-controlled watch of the present invention, the antenna has at least a portion protruding from the opening portion of the antimagnetic plate and positioned on the back cover side of the watch case.

Further, in the radio-controlled timepiece of the invention, the antenna has at least a portion protruding from the opening portion of the magnetism preventing plate and positioned on the one display plate side.

The antenna is disposed in such a position as to partially or entirely protrude from the opening portion. Therefore, the antenna can receive radio waves without the influence of the antimagnetic board. Therefore, in the radio-controlled timepiece as well, the timepiece device can be prevented from being affected by external magnetism without degrading the reception characteristics of radio waves. Therefore, accuracy can be improved in the table without affecting the driving operation of the pointer.

Further, in the radio-controlled watch of the present invention, the magnetism preventing plate is formed of at least one material selected from pure iron and permalloy.

Thus, the antimagnetic plates are formed of pure iron or permalloy. Therefore, high magnetic permeability can be obtained, and the watch device can be protected from external magnetism, and the accuracy of the watch can be improved without affecting the driving operation of the pointer.

Further, in the radio-controlled watch of the present invention, a non-magnetic member having a resistivity of 7.0 μ Ω -cm or less is provided on the inner surface of the antimagnetic plate.

With such a structure, a non-magnetic member having a resistivity of 7.0 μ Ω -cm or less is provided on the inner surface of the antimagnetic plate. Accordingly, the gain of the antenna can be increased, and the reception sensitivity and the frequency selectivity can be increased, so that the reception characteristics and the accuracy of the table can be improved.

Further, in the radio-controlled watch of the present invention, the non-magnetic member is provided in the opening portion of the magnetism prevention plate.

Therefore, the non-magnetic member is disposed in the opening portion of the antimagnetic plate at a position corresponding to the antenna. Accordingly, the reception sensitivity and the frequency selectivity can be improved, and the gain of the antenna can be increased, and the reception sensitivity and the frequency selectivity can be improved so as to improve the reception sensitivity and the accuracy of the table.

Further, in the radio-controlled watch of the present invention, the non-magnetic member is formed by bonding at least two materials selected from the following materials: gold, silver, copper, brass, aluminum, magnesium, zinc, and alloys thereof.

Gold, silver, copper, brass, aluminum, magnesium, or alloys thereof are a metal having a resistivity of 7.0 μ Ω -cm or less. By using such a metal as a nonmagnetic member fixed to the inner surface of the case band or the back cover of the watch case, the gain of the antenna can be increased, the reception sensitivity and the frequency selectivity can be improved, and the reception sensitivity and the accuracy of the watch can be improved.

Further, in the radio-controlled watch of the present invention, the non-magnetic member has a rising portion standing in the direction of the display panel, an

The rising portion abuts on a portion of the case, thereby controlling the rotation of the antimagnetic plate.

With such a structure, the rotation of the antimagnetic plate can be prevented, whereby the antimagnetic plate is easily positioned, and the assembly of the antenna, the watch case, and the antimagnetic plate is simplified. Therefore, the manufacturing process can be simplified and the cost can be reduced.

an antenna for receiving a radio wave including time information;

a case for accommodating the antenna and the watch device;

wherein the watch case is composed of a non-conductive material or a material having a low resistivity, and

an outer member formed of an electrically conductive material is provided, the material being attached to the outside of the watch case.

Further, in the radio-controlled timepiece of the invention, the exterior part covers an outer side surface of the case band of the case.

Further, in the radio-controlled watch of the present invention, the exterior part covers the upper surface of the case band of the watch case.

With such a structure, the case for housing the antenna is formed of a material having a non-conductive property or a low resistivity, and the outer member attached to the outside of the case, in particular, the outer member for covering the outside surface of the case body is conductive, for example, a metal.

Compared with a case in which the case for housing the antenna itself is formed of a conductive material, therefore, the distance between the antenna and the (e.g., a metal) external member as the conductive material can be increased. Therefore, it is difficult to cause failure of antenna reception. Therefore, the antenna can receive radio waves well, and thus, the reception performance and the accuracy of the watch can be improved.

By means of the electrically conductive outer part, such as a metal, it is furthermore possible to give the radio-controlled watch a metallic appearance. Thus, the visual perception appears to be that the case is formed of a solid metal. Therefore, by using a non-conductive material such as synthetic resin for the watch case, deterioration of the high-class feeling and the delicate appearance can be prevented.

Further, in the radio-controlled watch of the present invention, the non-conductive material constituting the watch case is formed of at least one non-conductive material selected from synthetic resin, rubber, and ceramics.

Therefore, the watch case, for example, a case band, a back cover, a bezel, and the like are made of a non-conductive material such as synthetic resin, rubber, or ceramics. Therefore, the antenna can receive radio waves well, and thus, the reception performance and the accuracy of the watch can be improved.

Further, in the radio-controlled watch of the present invention, the material having a low resistivity constituting the watch case includes at least one material having a low resistivity selected from the group consisting of gold, silver, copper, brass, aluminum, magnesium and alloys thereof.

Therefore, the watch case, for example, the case band, the back cover, the bezel, and the like are made of a material having a low resistivity such as gold, silver, copper, brass, aluminum, magnesium, zinc, or an alloy thereof. Therefore, the antenna can receive radio waves well, and thus, the reception performance and the accuracy of the watch can be improved.

Further, in the radio-controlled watch of the present invention, the conductive material constituting the outer member includes at least one conductive material selected from stainless steel, titanium, and a titanium alloy.

Therefore, the outer member may be composed of a conductive material such as stainless steel, titanium, or a titanium alloy, which is a metal having excellent appearance quality. Thus, the exterior part can be designed and manufactured in the same manner as a general watch which is not a radio-controlled watch. Thus, the design variants of the case of a watch that can be enhanced with radio control are comparable to those of a conventional watch.

Brief description of the drawings

Fig. 1 is a sectional view showing a case structure of a radio controlled watch according to an example of the present invention.

Fig. 2 is a graph for explaining an example of calculating a gain and a Q value of an antenna indicating the good or bad reception state.

Fig. 3 is an explanatory view showing an apparatus for performing a receiving test using an outer member for test.

Fig. 4 is an exploded perspective view showing a case structure of a radio controlled watch according to another example of the present invention.

Fig. 5 is a sectional view taken along the axis of a rod in fig. 4.

Fig. 6 is a sectional view showing a case structure of a radio controlled watch according to another example of the present invention.

Fig. 7 is a sectional view showing a case structure of a radio controlled watch according to another example of the present invention.

Fig. 8 is a sectional view showing a case structure of a radio controlled watch according to another example of the present invention.

Fig. 9 is a sectional view showing a case structure of a radio controlled watch according to another example of the present invention.

Fig. 10 is a plan view for explaining a state of setting a watch case and an antenna according to the present invention.

Fig. 11 is a sectional view for explaining a state of setting a back cover and an antenna according to the present invention.

Fig. 12 is a graph showing a relationship between the gain of the received signal and the case thickness according to the results of the experiment.

Fig. 13 is a graph showing a relationship between a gain of a received signal and a distance from an antenna to a case according to a result of an experiment.

Fig. 14 is a graph showing a relationship between the gain of the received signal and the thickness of the back cover according to the results of the experiment.

Fig. 15 is a graph showing a relationship between a gain of a received signal and a distance from an antenna to a back cover according to a result of an experiment.

Fig. 16 is a sectional view showing a case structure of a radio controlled watch according to another example of the present invention.

Fig. 17 is a sectional view showing a case structure of a radio controlled watch according to another example of the present invention.

Fig. 18 is a sectional view showing a case structure of a radio controlled watch according to another example of the present invention.

Fig. 19 is a sectional view showing a case structure of a radio controlled watch according to another example of the present invention.

Fig. 20 is a plan view, which is a view seen in the direction of the back cover of the magnetism preventing plate shown in fig. 19.

Fig. 21 is a sectional view showing a case structure of a radio controlled watch according to another example of the present invention.

Fig. 22 is a sectional view showing a case structure of a radio controlled watch according to another example of the present invention.

Fig. 23 is a sectional view showing a case structure of a radio controlled watch according to another example of the present invention.

Fig. 24 is a sectional view showing a case structure of a radio controlled watch according to another example of the present invention.

Fig. 25 is a plan view, which is a view seen in the direction of the back cover of the magnetism preventive plate shown in fig. 24.

Fig. 26 is a block diagram schematically showing the function of the radio-controlled table.

Fig. 27 is a sectional view showing a conventional example of a radio controlled watch structure using metal in a part of a watch case.

Fig. 28 is a sectional view showing a conventional example of the structure of a general watch using a magnetism preventing plate.

Fig. 29 is a sectional view showing a back cover according to an example in which a non-magnetic member is formed by electroforming.

Fig. 30 is a diagram for explaining a state of an antenna for setting a radio controlled watch according to the present invention.

Detailed Description

An embodiment (example) of the present invention will be described in more detail below with reference to the accompanying drawings.

(example 1)

As shown in fig. 1, a watch case a is constituted by: a case band 30, a back cover 33 attached to the lower surface of the case band 30, a bezel (not shown), and the like.

The case band 30 has a substantially cylindrical shape, and a glass 32 is attached to a shoulder portion 30a provided on the inner peripheral edge of the upper opening portion in the drawing through a seal gasket 31. Further, a back cover 33 is fixed to the lower opening portion in the drawing by a method such as press-fitting, screwing or screwing.

The back cover 33 shown in fig. 1 is attached to the case band 30 by press-fitting. Further, a packing 44 is interposed between a rising portion 33a and an inner side surface 30c of the watch case 30. Further, the case band 30 is formed of a metal, and the material of the metal will be described later.

The watch case 30 houses a movement 34 including a receiver, a CPU, a display driving portion, and the like of the radio-controlled watch, which are shown in fig. 26 as described above. A clock panel 35 and hands 36 as a time display section are provided above the movement 34 in the drawing.

The movement 34 is positioned by abutment of the face 35 on the lower surface of the internal projecting portion 30b, in the figures the projecting portion 30b forming a shoulder 30a of the watch case 30. Further, the movement 34 is inserted between the clock panel 35 and the resin intermediate frame 45 provided on the upper surface of the rising portion 33a of the back cover 33, and is thereby fixed.

Further, a predetermined space is provided between the movement 34 and the back cover 33, and an antenna 37 is provided in the space. The antenna 37 is constituted by a rod-shaped core member 38, the core member 38 is formed of a ferrite material, and a coil 40 is wound around the core member 38 and fixed to the lower surface of the core 34.

Further, in the present example, the nonmagnetic members 42 and 43 are provided on the inside surface 30c of the case band 30 and the inside surface 33c of the back cover 33. The non-magnetic member 42 has a plate shape, and is provided on an inner surface 33c at an inner side of the rising portion 33a of the back cover 33 opposite to the movement 34. Further, the non-magnetic member 42 is opposed to a plane including the axis AX of the core member 38, and is disposed in a position in which the antenna 37 protrudes in parallel.

Specifically, in fig. 1, the nonmagnetic member 42 is opposed to a horizontal plane including the axis AX of the core member 38, and is disposed in a position in which the antenna 37 protrudes in parallel, i.e., on the upper surface of the back cover 33.

However, the position of arrangement is not limited to the position in fig. 1, and the non-magnetic member may be arranged in a position in which the antenna 37 protrudes in parallel on the inner surface of the wristwatch case along at least one plane including the axis AX of the core member 38, for example, a position in which the case 30 protrudes, or a position in which the back cover 33 protrudes.

Further, the non-magnetic member 43 has a ring shape along the inside surface 30c of the case band 30, or has an arc plate shape constituting a part thereof, and is disposed in a position (a relative position) opposite to one end in the axial direction of the antenna 37.

The nonmagnetic members 42 and 43 are formed of a material having a resistivity of 7.0 μ Ω -Cm or less, which will be described later.

In the radio-controlled watch having the above-described structure, the CPU in the movement 34 operates the display driving section in accordance with the standard electric wave received by the antenna 37, thereby driving to always correct the pointer 36.

At this time, in the structure of the wristwatch case according to the present example, the nonmagnetic members 42 and 43 are disposed between the back cover 33 and the antenna 37. Therefore, interference of a resonance phenomenon located in the vicinity of the antenna by the case band 30 and the back cover 33 formed of metal can be reduced, and thus, the reception sensitivity can be improved.

1. A test for selecting the materials of the case band 30, the back cover 33 and the nonmagnetic members 42 and 43:

next, experiments related to selection of materials of the case band 30, the back cover 33, and the nonmagnetic members 42 and 43 and results thereof will be described.

1-1. selecting a metal with small reduction in reception sensitivity:

in order to select a metal having a small reduction in the reception sensitivity of the antenna 37, first, an antenna for test having a coil of 2000 turns with a wire diameter of 65 μm was disposed on a metal plate having a thickness of 0.5mm, and then a test was conducted, which transmitted a 40kHz signal from a transmitting antenna disposed at a predetermined position.

By comparing the gain of the peak height of the received signal with the Q value, the latter Q ═ fo/. DELTA.f is obtained from a frequency bandwidth. DELTA.f and a peak frequency fo, a reception state can be calculated.

It can be noted that the reception sensitivity is more improved if the gain is increased, and the frequency selectivity is more improved if the Q value is increased.

As a result of the experiment, in the case where the antenna is provided on gold, silver, copper, brass, aluminum, magnesium, zinc, or an alloy thereof, the gain is high (the reception sensitivity is high) by 2 to 3dB (decibel) as compared with the case where the antenna is provided on titanium, a titanium alloy, or stainless steel.

1-2 test using an external part for testing to select a material:

next, the same test was performed using an outer member for test corresponding to the case band 30 and the back cover 33.

Specifically, as shown in fig. 3, an exterior part 50 for test corresponding to the case band 30 and the back cover 33 accommodates an antenna 51 for test corresponding to the antenna 37, the exterior part 50 being mounted on a resin plate 52. In this state, an electric wave having a constant frequency is radiated from the transmitting antenna 53 disposed at a predetermined position to measure the receiving state of the antenna 51 for the test.

As a result of the experiment, as shown in table 1 below, when a case portion 50a corresponding to the case band 30 and a cover portion 50b corresponding to the back cover 33 were formed of a metal such as stainless steel (which is known to have reduced receiving sensitivity), it was seen that the Q value was reduced to 5, which is not preferable for the radio-controlled watch (experimental example 1).

When the case portion 50a is formed of a metal such as stainless steel (which is known to have a reduced reception sensitivity) and the cover portion 50b is formed of a metal such as brass (which is known to have a high reception sensitivity), the Q value is about 8, so that the reception sensitivity can be improved (example 2 of the experiment).

Thus, assuming for a watch, an exterior part is used whose case portion 50a remains formed of a metal such as stainless steel, while the cover portion 50b is formed of a metal such as stainless steel on the outside and of a metal such as brass on the inside. Thus, the Q value is 8 to 9, which is set in a preferred state. In addition, the gain of the antenna can also be improved by 1 to 2dB, compared with the case where only a metal such as stainless steel is used (example 3 of the experiment).

Table 1 test results using outer member for test

	Shell part 50a	Cover part 50b	Q value
	Shell part 50a	Cover part 50b	Q value	Test example 1	Metals such as stainless steel	Metals such as stainless steel	5
Test example 2	Metals such as stainless steel	Metal such as brass	Is approximately 8	Test example 1	Metals such as stainless steel	Metals such as stainless steel	5
Test example 2	Metals such as stainless steel	Metal such as brass	Is approximately 8	Test example 3	Metals such as stainless steel	Outside: metal interiors such as stainless steel: metal such as brass	8 to 9

From the results of the experiment, it was confirmed that even if the case band 30 and the back cover 33 are formed of a metal having a reduced reception sensitivity, wherein a metal having a high reception sensitivity is provided on the inside, the reception sensitivity of the antenna 37 provided on the inside of the case band can be improved.

1-3 relationship between resistivity and receive sensitivity:

on the other hand, the resistivities of the metals used in the tests were compared with each other. With reference to titanium or stainless steel, which decreases the reception sensitivity, it can be found that the resistivity is high, i.e., 55 to 74 μ Ω -Cm. With reference to aluminum, which has a high reception sensitivity, it can be found that the resistivity is low, i.e., 2.69 μ Ω -Cm.

In order to confirm the relationship between the resistivity and the reception sensitivity, metals disposed on the outside and the inside were combined according to the resistivity. Therefore, it has been found that a high reception sensitivity can be maintained even if the resistivity of the metals combined is high by setting the resistivity of the metal having a high reception sensitivity to 7 μ Ω -Cm or less.

As a result, it was confirmed that even though the case band 30 and the back cover 33 are formed of a metal having a reduced reception sensitivity, a small Q value (low frequency selectivity) and a high resistivity, for example, titanium alloy, stainless steel or tantalum carbide, which has excellent appearance quality, while the non-magnetic members 42 and 43 are formed of a metal having a high reception sensitivity, a high Q value (excellent frequency selectivity) and a low resistivity and a resistivity of 7 μ Ω -Cm or less, for example, gold, silver, copper, brass, aluminum, magnesium, zinc or an alloy thereof, the reception sensitivity can be improved.

1-4 relationship between thickness and reception sensitivity in the nonmagnetic members 42 and 43:

in order to examine the relationship between the thickness and the reception sensitivity in the non-magnetic members 42 and 43, a test was conducted for forming the case portion 50a and the lid portion 50b shown in fig. 3 by stainless steel (austenite type), and a thin aluminum material was provided on the inside of the lid portion 50b so as to gradually increase the thickness thereof from zero (no aluminum material).

Therefore, it was found that the Q value increased from 9.9 at a thickness of 0 to 14.3 at a thickness of 500. mu.m, and it was also found that 14.6 was obtained at a thickness of 1000. mu.m while maintaining an accurate value with the increase in thickness. Further, it was also found that the gain of the antenna was improved by about 3dB at a thickness of 500 μm as compared with the case of 0.

As a result, when the thickness of the aluminum material reaches 50 μm, the gain and Q value increase, and thus, become constant and maximum at a thickness of about 1000 μm. Therefore, it has been found that the thickness of the nonmagnetic members 42 and 43 is preferably set to 50 μm or more.

Further, with reference to the upper limit of the thickness, it is preferable that the thickness should be set to 2000 μm or less in consideration of the distance between the case band 30 or the back cover 33 and the movement or the antenna 37 and the convenience of handling the non-magnetic members 42 and 43 during manufacturing and assembling, etc.

1-5 consideration of the results of the test

According to the results of the respective experiments and the like, it is preferable that the case body 30 and the back cover 33 should be formed of titanium, titanium alloy, stainless steel, tungsten carbide or tantalum carbide having a reduced reception sensitivity, a small Q value (a low frequency selectivity), and an excellent appearance quality, and the non-magnetic members 42 and 43 should be formed of gold, silver, copper, brass, aluminum, magnesium, zinc or their alloys having a high reception sensitivity, a large Q value (an excellent frequency selectivity), a low resistivity, and a resistivity of 7 μ Ω -Cm or less, and further, the thickness should be set to 50 to 2000 μm.

Further, the nonmagnetic members 42 and 43 need not be formed of only one of the metals, but the same advantages can be obtained even if they bond at least two of the metals by diffusion bonding, brazing, bonding, caulking, or the like.

Next, the fixing of the case band 30 and the back cover 33 to the nonmagnetic members 42 and 43 will be described.

In the case where the case band 30 and the back cover 33 are formed as separate members from the nonmagnetic members 42 and 43, respectively, they are usually connected by press-fitting, caulking, welding, brazing, or an adhesive.

Further, the non-magnetic members 42 and 43 may be integrally bonded and fixed in the state of the material of the case band 30 and the back cover 33, and then, various shapes may be arranged.

In this case, a clad material is used, which is heated, diffused and bonded in a state where a non-magnetic member formed of gold, silver, copper, brass, aluminum, magnesium, zinc or an alloy thereof is in press contact with materials of the case 30 and the back cover 33 formed of titanium, a titanium alloy, stainless steel or the like, and further, is bonded to have a predetermined thickness by rolling.

The case body 30 and the back cover 33 are formed of a clad material, and the case body 30 and the back cover 33 and the nonmagnetic members 42 and 43 are thus formed in an integrated bonded state.

Further, the non-magnetic members 42 and 43 may be formed and fixed so as to be bonded to the case band 30 and the back cover 33.

In this case, the nonmagnetic members 42 and 43 are formed in predetermined positions of the case band 30 and the back cover 33 by electroforming using a wet coating method, a metal spraying method, or the like.

Referring to the electroforming method, a case will be described as an example, in which copper is deposited on the back cover 33 composed of stainless steel to form the nonmagnetic member 42.

First, as shown in fig. 29, a mask 60 made of an organic material such as an epoxy resin is formed on the surface of the back cover 33, excluding a predetermined portion inside the rising portion 33a of the back cover 33.

Next, electrolytic degreasing is performed on the inner surface of the back cover 33 where the mask 60 is not formed, and rinsing is performed with water. Then, a cathode is connected to the back cover 33, and then electroforming is performed in a copper sulfate bath to precipitate copper 61.

At this time, the composition and conditions in the tank were set as follows.

250g/l copper sulfate, 60g/l sulfuric acid,

the temperature is between 20 and 50 ℃,

current density 2 to 20A/dm²，

A time of 20 to 30 hours, (which is set corresponding to the thickness of the precipitate, under which condition a thickness of about 150 μm is obtained in six hours), and

the pH value is 0.8 to 1.1.

After the copper 61 is thus deposited to have a predetermined thickness, the back cover 33 is immersed in an organic solvent to peel off the mask 60. Thereafter, the back cover 33 is rinsed with water and dried so that the non-magnetic member 42 is formed in a predetermined position of the back cover 33.

Although the nonmagnetic members 42 and 43 are provided on the case band 30 and the back cover 33, respectively, in the case structure shown in fig. 1, the reception sensitivity can be improved even if the nonmagnetic members are simply provided on the case band 30 or the back cover 33.

Therefore, it is not necessary to always provide a non-magnetic member on the case band 30 and the back cover 33.

Further, it is also possible to have a structure in which a resin plate is provided between the nonmagnetic members 42 and 43 and the antenna 37, or the surfaces of the nonmagnetic members 42 and 43 are covered with a resin layer, thereby preventing the antenna 37 and the nonmagnetic members 42 and 43 from contacting each other to damage the antenna 37.

According to example 1, the reception sensitivity can be improved without using a special structure such as a glass for a case structure, for example, the case band 30 and the back cover 33. Therefore, a radio controlled watch can be provided to receive electric waves including time information and the like without hindering the portability thereof.

Further, titanium, stainless steel, or the like can be used for the watch case such as the case band 30 and the back cover 33. Therefore, a wristwatch case can be used which has stable waterproof quality and appearance quality with a high quality feeling.

Further, the watch case such as the case band 30 and the back cover 33 may be designed and manufactured in a manner similar to an ordinary watch which is not a radio-controlled watch. Thus, the design variants of the watch case in a radio controlled watch can be improved as compared to a conventional watch.

(example 2)

Fig. 4 is an exploded perspective view showing a case structure of a radio controlled watch according to another example of the present invention, and fig. 5 is a sectional plan view taken along an axis of a bar.

The radio controlled watch according to the present example has two sets including a first outer member 53 and a second outer member 54 in a case a composed of a watch case 50, a back cover 51 and a windshield 52.

In this example, a structure in which a resin plate is provided between the nonmagnetic members 42 and 43 and the antenna 37 and the surfaces of the nonmagnetic members 42 and 43 are covered with a resin layer to prevent the antenna 37 and the nonmagnetic members 42 and 43 from contacting each other to damage the antenna is applied to the wristwatch case as in example 1.

Specifically, a non-conductive material such as a resin plate, or a material having a low resistivity is used for the case band 50 and the back cover 51, and the antenna is surrounded by these components, thereby preventing the antenna from being damaged.

The case band 50 and the back cover 51 are formed of a non-conductive material, for example, a synthetic resin, rubber, or ceramic or a material having a low resistivity such as gold, silver, copper, brass, aluminum, magnesium, or an alloy thereof. Further, the windshield 52 is formed of a glass, which is a non-conductive material and is fixed to the shoulder portion of the case band 50 by a gasket.

As shown in fig. 4, the watch case 50 has a cylindrically projecting rod 56. As shown in fig. 5, a clock face, a hand (not shown), and a movement 60 and a rod antenna 61 are accommodated in the watch case.

The clock face is formed of a non-conductive material such as synthetic resin or ceramic. The movement 60 is provided with a shoulder portion 63 which includes a large lower portion having a small diameter. The back cover 51 has an annular projection 66 and is fixed to the case band by a packing 65 with screws 64, and the annular projection 66 is pushed up to the shoulder portion 63 of the movement 60 to press and fix the movement and the clock face to the shoulder portion of the case band 50.

The rod antenna 61 is constituted by a core member 67 and a coil 68 wound around the core member and bonded to the lower portion of the large shoulder portion 63 of the core 60 in parallel with the rod 56. That is, the rod antenna is accommodated in a low position in the lower part of the case as shown in fig. 5.

The first outer member 53 and the second outer member 54 are formed of a thin conductive material such as stainless steel, titanium, or a titanium alloy.

As shown in fig. 4, the first outer member 53 has a circular disk shape and includes a slope 53a provided outwardly and downwardly in the upper portion and a shoulder portion 53b on the lower surface, and the first outer member 53 is bonded to a flat portion 50d of an annular projecting portion on the upper surface of the case band 50.

On the other hand, the second outer member 54 is composed of a side surface covering portion 54a having a cylindrical shape and covering the side surface of the case band, and an engaging portion 54b projecting inward in the upper portion. Further, the upper surface of the engaging portion 54b is a slope having the same slope as that of the slope 53a of the first outer member 53, thereby forming an appearance.

As shown in fig. 4, further, a band attaching leg portion 76 is formed on both ends. The side surface covering portion 54a is fixed to the side surface of the case band 50 with a screw 71. Further, the side surface covering portion 54a is provided with an opening portion 73, and the rod 56 protrudes into the opening 73. The engaging portion 54b engages with the shoulder portion 50c of the case band 50 with press-fit contact.

The side surface covering portion 54a has a small thickness in the radial direction, and the case band 50 has a large thickness. Therefore, the side surface covering portion 54a is disposed away from the rod antenna 61.

Although the case band has a large thickness, in particular, the side surface covering portion 54a of the second outer member 54 is large enough to cover the side surface of the case band 50, and therefore, the drawback of the reception is greatly alleviated.

According to example 2, a watch case such as a case 50 and a back cover 51 housing an antenna 61 is formed of a non-conductive material or a material having a low resistivity. Further, the first outer member 53 and the second outer member 54 attached to the outside of these watch cases, in particular, the second outer member 54 for covering the outside surface of the watch case, are a conductive material such as metal.

Compared with a case in which the case itself for accommodating the antenna 61 is formed of a conductive material, therefore, the distance between the antenna 61 and the first and second outer members 53 and 54 (e.g., conductive metal) can be increased. Therefore, it is difficult to cause a reception defect of the antenna 61. Therefore, the antenna 61 can receive the electric wave well and can improve the reception characteristic and accuracy in the watch.

Further, a non-conductive material such as a resin plate or a material having a low resistivity is applied to the case band 50 and the back cover 51, and the antenna is surrounded by these components. Therefore, the damage of the antenna can be prevented.

Furthermore, the radio-controlled watch is given a metallic appearance by the first outer member 53 and the second outer member 54 of conductive metal. The watch case can thus be visually seen as a solid metal. Although a non-conductive material such as synthetic resin is used for the watch case, the high quality feeling and the fine visual sense can be prevented from being deteriorated.

(example 3)

According to "1. result of experiment of the case band 30, the back cover 33 and the nonmagnetic members 42 and 43 selected according to example 1", wherein the case band and the back cover are formed of a nonmagnetic member such as gold, silver, copper, brass, aluminum, magnesium, zinc or an alloy thereof, the metal having a resistivity of 7 μ Ω -Cm or less, the reduction of the reception sensitivity can be suppressed, and a metal case can be used for a radio-controlled watch.

If a part of the case band and the back cover is formed of a non-magnetic member and even if the other part is formed of titanium, a titanium alloy, stainless steel, tungsten carbide, tantalum carbide, or the like, the receiving sensitivity can be brought into an excellent state.

Further, the non-magnetic member need not be formed of only one of the metals, and the same advantages can be obtained even if the wristwatch case or a part thereof is formed by bonding at least two of the metals by diffusion bonding, brazing, an adhesive, caulking, or the like.

Next, an example will be described based on the results of the above-described experiments and the like.

A watch case 30 has an almost cylindrical shape, and a glass 32 is attached to a shoulder portion 30a provided on the inner periphery of the upper opening portion in the drawing through a seal gasket 31. Further, a back cover 33 is attached to the lower opening portion in the drawing by a method such as press-fitting, screwing or screwing.

The back cover 33 shown in fig. 6 is attached to the case band 30 by a press-fitting method, and a packing 44 is interposed between the annular portion 33a and the inner side surface 30c of the case band 30.

The case band 30 and the back cover 33 according to the present example were formed of body portions 30d and 33d composed of brass material having a resistivity of 7.0 μ Ω -Cm or less, which brought the reception sensitivity to an excellent state in the above test, and mirror-finished, and then, plating layers 30e and 33e such as palladium (Pd) were formed on the surfaces by a wet plating method and thereby finished.

The plating layers 30e and 33e of the case band 30 and the back cover 33 are formed by a wet plating method, which will be described later.

To form a base plating layer, first, the plating on the body portions 30d and 33d is performed under the following conditions:

electroplating bath (component: NaSnO)₃·3H₂O 60g/l，CuCN 20g/l，K₂SO₃H10 g/l, KCN (free) 30g/l, KOH 60g/l, Zn (CN)₂ 5g/l)，

The temperature of the tank is 50 ℃,

current density 2.4A/dm²，

pH 12.5，

A precipitation rate of 0.33 μm/min, and

the time is 6 minutes.

Thus, a base plating layer of Cu-Sn-Zn alloy having a thickness of about 2 μm is formed on the surfaces of the body portions 30d and 33 d.

Next, plating on the base plating layer was performed under the following conditions, thereby forming a plating layer of Sn-Cu-Pd alloy.

Electroplating bath:

(composition: NaSnO₃·3H₂60g/l of O (Sn conversion 26.7g/l), 20g/l of CuCN (Cu conversion 14.2g/l), K₂SO₃H10 g/l, KCN (free) 30g/l, KOH 60g/l, K₂Pd(CN)₄·3H₂O30 g/l (Pd conversion amount 9.3g/l)),

electroplating conditions are as follows:

the temperature of the tank is 50 to 55 ℃,

current density 2.0A/dm²，

The current efficiency is 47.8 percent,

the pH value of the mixture is 12.5 to 13,

a precipitation rate of 0.33 μm/min, and

the time is 9 minutes.

By electroplating, the thickness was about 3 μm, the hardness (Hv) was about 300 and the density was 9.6g/cm³Is formed on the base plating layer.

The composition of the coating is determined in a simplified manner by means of a scanning electron microscope and an X-ray microanalyzer. Thus, a ternary alloy, Sn: 17.12% (by weight), Cu: 44.22% (by weight), Pd: 38.66% (by weight).

Then, plating was performed on the Sn-Cu-Pd alloy under the following conditions to form a plating layer for polishing treatment. Electroplating bath:

(PALLABARRIGHT-SSS (trade name) manufactured by JAPAN PURE CHEMICAL CO., LTD).

Electroplating conditions are as follows:

the temperature of the cell was 55 c,

current density 5A/dm²，

pH 7.6，

A precipitation rate of 0.33 μm/min, and

the time is 6 minutes.

By the electroplating, a white and glossy Pd plating layer having a thickness of about 2 μm was formed, and thus, the plating layers 30e and 33e were completed.

Even if a corrosion resistance test is performed, that is, the case body 30 and the back cover 33 provided with the plating layers 30e and 33e as described above are immersed in artificial sweat (at a temperature of 40 ℃) for 24 hours, the surface does not discolor, but has an excellent corrosion resistance, the artificial sweat containing the following components:

9.9g/l of sodium chloride,

0.8g/l of sodium sulfate,

7.1g/l of urea,

0.19ml/l of ammonia water,

sucrose 0.2g/l, and

lactic acid (50%) 0.8 ml/l.

Even if a heating test is conducted, leaving the case 30 and the back cover 33 at a temperature of 200 ℃ for 5 hours, peeling of the plating layers 30e and 33e is not observed at all, and therefore the heat resistance thereof can be improved.

The watch case 30 houses a movement 34 including a receiver, a CPU, a display driving portion, and the like of the radio-controlled watch, which are shown in fig. 26 as described above.

A clock panel 35 and hands 36 serving as a time display section are provided above the movement 34 in the figure. In the drawing, the movement 34 is positioned abutting against the clock panel 35 on the lower surface of the inner projecting portion 30b forming the shoulder portion 30a of the case band 30, and is inserted between the clock panel 35 and the resin intermediate frame 45 provided on the upper surface of the rising portion 33a of the back cover 33, and is thereby fixed.

Further, a predetermined space is provided between the movement 34 and the back cover 33, and the antenna 37 is provided in the space. The antenna 37 is constituted by a core member 38 (formed of a ferrite material or the like) in a rod shape and a coil 40 wound around the core member 38, and is fixed to the lower surface of the core 34.

In the radio-controlled watch having the structure as described above, the CPU in the movement 34 operates the display driving section, whereby the pointer 36 is always driven to be corrected in accordance with the standard electric wave received by the antenna 37. At this time, according to the present example, the case band 30 and the back cover 33 are formed of a non-magnetic member in the watch case. Accordingly, interference of a resonance phenomenon in the vicinity of the antenna can be reduced, whereby the reception sensitivity can be improved.

Further, as described above, the case band 30 and the back cover 33 are subjected to the surface polishing treatment. Thus, corrosion resistance and heat resistance necessary for use in a watch case are provided, and furthermore, a white base metal gloss gives a sense of quality and a sense of high quality. Therefore, the quality of the appearance can also be improved.

(example 4)

The structure according to this example is the same as that of example 3 described above, and the materials and surface polishing treatments of the case band 30 and the back cover 33 are different from each other. For this reason, the material and surface polishing process will be described in detail.

The case band 30 according to the present example is formed of a body portion 30f composed of a tungsten carbide material (a hard material) and subjected to mirror-finish processing, whereas a plating layer 30g is formed on the surface by dry plating and thus surface-processed.

On the other hand, the back cover 33 is formed of a brass material, which is a non-magnetic member having a resistivity of 7 μ Ω -Cm or less, and subjected to mirror polishing, the base plating layer of Cu-Sn-Zn alloy and the plating layer of Sn-Cu-Pd alloy, which have been described in example 3, are formed by a wet plating method, and a plating layer 33i (the same as the plating layer formed on the case band 30) is formed on the surface by a dry plating method, and thus surface-treated.

Plating was performed by the following procedure to form plating layers 30g and 33 i.

First, a base plating layer of a Cu-Sn-Zn alloy is formed on the surface of the back cover 33, and a plating layer of a Sn-Cu-Pd alloy is formed on one surface thereof, by an electroplating bath and the conditions described in example 3.

Next, the back cover 33 and the body portion 30f formed of tungsten carbide are degreased, washed, and dried. Thereafter, the body portion 30f and the back cover 33 were set in an ion plating apparatus, the inside of the apparatus was evacuated, and then, argon arc was introduced to set the degree of vacuum in the apparatus to 1.0X 10^-2And (4) supporting.

A thermionic filament and a plasma electrode disposed within the apparatus operate to generate an argon plasma, thereby cleaning the surface with an ion bombardment for 10 minutes.

Thereafter, a nitrogen gas was introduced into the apparatus, and the degree of vacuum in the apparatus was maintained at 2.0X 10^-3In torr, plasma was generated by a plasma gun of the apparatus, and Ti was simultaneously evaporated for 5 minutes, whereby a TiN layer having a thickness of 0.25 μm was formed on the surfaces of the case 30 and the back cover 33.

Further, the evaporation of Ti and the introduction of nitrogen gas were stopped, and then, an Au-Ti alloy plating layer having a thickness of 0.3 μm was formed on the TiN layer by the evaporation of Ti containing 50 atomic percent, thereby completing the plating layers 30g and 33 i.

The case band 30 and the back cover 33 provided with the plating layers 30g and 33i as described above have the color and luster of gold, and as the color tone thereof, a uniform dedicated gold color tone of 1N to 14 colors satisfying the swiss gold plating color standard can be displayed.

The color tones actually measured by the colorimeter were L ' 80, a ' 1.0, and b ' 15.0. According to the results obtained by the analysis by the X-ray photoelectron spectroscopy method, the plating layers 30g and 33i thus formed were constituted: 88 atomic percent gold, 6.5 atomic percent titanium, 0.5 atomic percent nitrogen, 2 atomic percent oxygen, and 3 atomic percent carbon.

Referring to the case body 30 and the back cover 33, even if the corrosion resistance test was performed for 24 hours using the same artificial sweat as in example 3, no corrosion and discoloration were found at all.

In the wristwatch case according to the present example, even if the case band 30 is formed of tungsten carbide, the back cover 33 is formed of a nonmagnetic member. Therefore, interference of the resonance phenomenon near the antenna can be reduced, and thus, the reception sensitivity can be improved.

Further, as described above, the plating layer is formed on the case band 30 and the back cover 33, and is subjected to the surface polishing treatment. Thus, the use as a watchcase or the like provides a necessary corrosion resistance. Further, the color tone of gold has a high-class feeling. Therefore, the appearance quality can also be improved.

In some cases in which tungsten carbide as in the present example is used for the case band 30, the surface is simply subjected to mirror polishing treatment, and can thus be used as a case even without performing dry plating.

(example 6)

The structure according to this example is also the same as that of example 3 described above, and the materials and surface polishing treatments of the case band 30 and the back cover 33 are different from each other. For this reason, the material and surface polishing process will be described in detail.

The case band 30 according to the present example is entirely formed of a stainless steel material (austenite type), and a hair line pattern polishing process is performed on the surface.

On the other hand, in the back cover 33, the body portion 33f is formed of a stainless steel material (austenite type), and the filler 33g buried and brazed in the opening portion provided on the body portion 33f is formed of a brass material having a non-magnetic member with a resistivity of 7 μ Ω -Cm or less. Further, then, a plating layer 33h is formed on a surface by a wet plating method and a dry plating method and thus surface treatment is completed.

The plating layer 33h is formed by performing electroplating in the following process.

First, electroplating was performed under the same conditions as described in example 3 above, and a plating layer of a Cu-Sn-Zn alloy, a plating layer of a Sn-Cu-Pd alloy, and a Pd plating layer were continuously formed on the surface of the filler 33g composed of a brass material.

Next, the body portion 30f formed of a stainless steel material is washed with an organic solvent together with the filling member 33g provided with the plating layer, and set in the ion plating apparatus.

Thereafter, the inside of the apparatus was evacuated to 1.0X 10^-5Then introducing argon gas to 3X 10^-3And (4) supporting. Then, the thermionic filament and a plasma electrode disposed within the apparatus are driven to form an argon plasma.

At this time, -50V potential is applied to the back cover 33 to perform an ion bombardment cleaning for 10 minutes. Thereafter, the introduction of argon gas was stopped, and a nitrogen gas was introduced into the apparatus, and the degree of vacuum in the apparatus was maintained at 1.0X 10^-3Torr, plasma was generated by a plasma gun disposed within the apparatus, and Ti evaporation lasted for 10 minutes. As a result, a coating film formed of Ti nitride having a nitriding degree of 0.2 was formed on the surface of the back cover 33 with a thickness of 0.5 μm, and the inside of the apparatus was evacuated to 1.0X 10^-5And (4) supporting.

Next, argon gas was introduced into the apparatus to 1.0X 10^-3Thus, a plasma was generated, and then, a gold-cobalt mixture having 55 atomic% of gold and 45 atomic% of cobalt was evaporated, and when the thickness of the precipitated gold-cobalt alloy film reached 0.3 μm, the evaporation of the gold-cobalt mixture was stopped.

As a result of analysis by X-ray photoelectron spectroscopy, the plating layer 33h thus formed contained 63 atomic% of gold and 37 atomic% of cobalt. Further, the back cover 33 provided with the plating layer 33h has a bright and uniform white tone.

In the wristwatch case according to the present example, even if a part of the case band 30 and the back cover 33 is formed of a stainless material, the back cover 33 may have a part formed of a non-magnetic member. Therefore, interference of the resonance phenomenon near the antenna can be reduced, and thus, the reception sensitivity can be improved.

However, as described above, the plating layer 33h is formed on the filler 33g and the body portion 33f in the back cover 33, and surface polishing can be performed. Thus providing the necessary corrosion resistance for the watch case. Further, there is a high-quality white tone. Therefore, the appearance quality can also be improved.

Preferably, the opening portion of the body portion 33f of the back cover 33 according to the present example should be formed slightly larger than the outer shape of the antenna 37.

(example 7)

Watch case 30 according to the present example is formed entirely of an 18K alloy material (containing silver and copper) which is a non-magnetic member having a resistivity of 7 μ Ω -Cm or less, and the surface is subjected to mirror polishing treatment.

The back cover 33 is entirely formed of a stainless steel material (austenite type), and in the wristwatch case according to the present example, the case band 30 can be formed of a nonmagnetic member even if the back cover 33 is formed of a stainless steel material. Therefore, interference of the resonance phenomenon near the antenna can be reduced, and thus, the reception sensitivity can be improved.

The wristwatch case according to each of examples 3 to 7 is constituted by a case band 30 and a back cover 33, and it is also possible to use a wristwatch case in which a bezel and a ring are provided in an upper part of the case band 30. In this wristwatch case, if any one of the body, the bezel and the back cover is formed of a non-magnetic member, the receiving sensitivity can be improved.

Further, in addition to the entire structure being formed of the non-magnetic member, even if only a part of the body, the bezel, and the back cover is formed of the non-magnetic member, the reception sensitivity can be improved. In this case, it is effective that only a portion to which the antenna 37 protrudes in parallel, or an opposite portion to the end of the antenna 37 is formed of a non-magnetic member, which is preferable.

Further, in addition to using only one kind of non-magnetic member, a combination of a plurality of non-magnetic members may be used.

(example 8)

First, an experiment for checking the relationship between the reception sensitivity and a wristwatch case was performed in the following manner.

2. A test for checking the relationship between the reception sensitivity and the case:

2-1 summary of the experiments

As shown in fig. 10 and 11, the body thickness T1 of case band 25, the distance D1 between antenna 26 and the inner surface of case band 25, the back cover thickness T2 of back cover 27, and the distance D2 between antenna 26 and the inner surface of back cover 27 are selected as parameters.

The relationships between the four parameters and the gain as the peak height of the signal received by the antenna 26 were obtained from experiments, respectively.

The case 25, the antenna 26 and the back cover 27 in each test to be described below are the same as those for the test formed on the assumption that they are used as a watch case.

Further, as for the material of the case band 25 and the back cover 27, stainless steel, titanium alloy, gold, silver, copper, brass, aluminum, zinc, magnesium, or an alloy thereof, and an alloy of tungsten carbide and tantalum carbide containing a hard metal are selected in consideration of high workability, life, corrosion resistance, high appearance quality of the product, price, and the like.

In all experiments, there was an error of several dB gain. However, the relationship between the individual parameters and the gain (curve of the graph) changes little. Therefore, in various tests (to be described later), various values are shown in using stainless steel as the case band 25 and the back cover 27 (particularly, austenitic stainless steel is preferable, for example, SUS304L, SUS316L, and the like).

2-2 relationship between body thickness T1 and receive sensitivity:

in this test, the gain of the received signal was measured as a function of the satellite thickness T1 from 0 to 5000 μm.

In this test, as the antenna provided in the case band 25, an antenna for test having 1500 turns of a wire diameter of 65 μm was used.

Further, a distance D1 between case band 25 and antenna 26 is set to be constant 1000 μm, while a back cover thickness T2 for back cover 27 is 800 μm, and a distance D2 between antenna 26 and back cover 27 is set to be constant 100 μm. Then, an experiment was conducted in which a 40kHz signal was transmitted from a transmitting antenna disposed at a predetermined position.

As a result, as shown in fig. 12, when the body thickness increases, the gain of the received signal gradually decreases from about-50 dB, where the body thickness T1 is 0 μm (a state where the case band is not provided). This reduction reaches saturation when the bulk thickness T1 reaches 5000 μm.

The solid line shown in fig. 12 is an approximate curve obtained from the experimental data.

According to the above-described experiments, it has been found that when the bulk thickness T1 exceeds 5000 μm, the gain decreases to saturate to a constant, and the value obtained at this time is minimal. By setting the bulk thickness T1 to 0 to 5000 μm, the gain can be improved for the minimum value.

In view of the strength of the wristwatch case used in the above range, it is preferable that the body thickness T1 should be set within a range of 300 μm to 5000 μm of the practical maximum value. Further, in order to form an optimum body in consideration of appearance, workability, corrosion resistance and the like of the wristwatch case, the body thickness T1 should preferably be set in the range of 500 to 2000 μm.

2-3 relationship between the distance D1 from the antenna 26 to the case band 25 and the reception sensitivity:

in this test, the gain of the received signal was measured as a function of the distance D1 between the antenna 26 and the case band 25 from 0 to 40000 μm.

Fig. 13 shows the measurement results from 0 to 20000 μm.

Further, the body thickness T1 for the case band 25 is 2000 μm, and the back cover thickness T2 for the back cover 27 is 800 μm, and the distance D2 between the antenna 26 and the back cover 27 is set to be constant, that is, 100 μm. Then, an experiment was conducted in which a 40kHz signal was transmitted from a transmitting antenna disposed at a predetermined position.

As a result, as shown in fig. 13, when the distance D1 increases from about-54.5 dB, which is 0 μm (a state where a part of the antenna 26 is in contact with the case band 25), the gain of the received signal gradually decreases.

In this test, the gain of the received signal was-50.34 dB in the case with only back cover 27 (i.e., in the case with case 25 removed). When the gain has the same value as described above, the distance D1 between the antenna 26 and the case band 25 is obtained, and therefore, the rise in gain reaches saturation.

The distance D1 by which the gain is thus saturated is 40000 μm, which is not shown in fig. 13. Even if the antenna 26 and the case band 25 are separated from each other by a large distance, the gain is not increased. The solid line shown in fig. 13 is an approximate curve obtained from the experimental data.

From the above-described experiments, it has been found that the gain can be improved and the reception sensitivity can be improved if the distance D1 between the antenna 26 and the case band 25 is increased, and the gain is saturated to a constant value if the distance D1 exceeds 40000 μm.

If the distance D1 is set to 0 to 40000 μm, the gain can be improved. Considering a size usable as a watch case in the above range, the distance D1 should preferably be set to 500 to 10000 μm.

2-4 relationship between back cover thickness T2 and receive sensitivity:

in this experiment, the gain of the received signal was measured as a function of the back cover thickness T2 from 0 to 5000 μm.

Fig. 14 shows the measurement results from 0 to 30000 μm.

In this test, an antenna for test having 1500 turns of a wire diameter of 65 μm was used as an antenna.

Further, a distance D1 between case band 25 and antenna 26 is set to be constant, i.e., 1000 μm, while a body cover thickness T1 for case band 25 is 2000 μm, and a distance D2 between antenna 26 and back cover 27 is set to be constant, i.e., 100 μm. Then, an experiment was conducted in which a 40kHz signal was transmitted from a transmitting antenna disposed at a predetermined position.

As a result, as shown in fig. 14, it has been found that the gain of the received signal suddenly decreases from 0 μm (the state where the back cover 27 is not provided) to about-43.4 dB of 800 μm, and the gain does not vary greatly with the thickness of the back cover of 800 μm to 5000 μm. 5000 μm is not shown in FIG. 14.

In other words, it has been found that the back cover thickness T2 has a minimum value of 800 μm. The solid line shown in fig. 14 is an approximate curve obtained from the experimental data.

The minimum value is practically allowable, and the back cover thickness T2 should preferably be set in the range of 100 μm to the practical maximum value 50000 μm in consideration of the strength of the wristwatch case used in the above range.

Further, in order to form an optimum back cover in consideration of appearance, workability, corrosion resistance and the like of the wristwatch case, the body thickness T2 should preferably be set in the range of 300 to 2000 μm.

2-5 distance D2 from antenna 26 to back cover 27 and reception sensitivity:

in this experiment, the gain of the received signal was measured as a function of the distance D2 between the antenna 26 and the back cover 27 from 0 to 5000 μm.

In this test, 2000 turns of an antenna for test having a wire diameter of 65 μm was used as an antenna for setting.

Further, the body thickness T1 for the case band 25 is 2000 μm, and the distance D1 between the case band 25 and the antenna 26 is set to 10000 μm. Then, an experiment was conducted in which a 40kHz signal was transmitted from a transmitting antenna disposed at a predetermined position.

As a result, as shown in fig. 15, when the distance D2 increases from 0 μm (a state where a part of the antenna 26 is in contact with the back cover 27) at about-49.6 dB, the gain of the received signal gradually increases.

In this test, the gain of the received signal was-38.8 dB in the case of the watch case only with the watch case 25 (i.e., in the case with the back cover 27 removed). When the gain has the same value as described above, the distance D2 between the antenna 26 and the back cover 27 is obtained, and therefore, the rise in gain reaches saturation.

The distance D2 by which the gain rises and thereby reaches saturation is 5000 μm. The gain can be improved even if the antenna 26 and the back cover 27 are separated from each other by a large distance. The solid line shown in fig. 15 is an approximate curve obtained from the experimental data.

From the above-described experiments, it has been found that if the distance D2 between the antenna 26 and the back cover 27 is increased, the gain can be improved, and the reception sensitivity can be improved. However, if the distance D2 exceeds 5000 μm, the gain rises to saturate to a constant value.

If the distance D2 is set to 0 to 5000 μm, the gain can be improved. Considering a size usable as a watch case in the above range, the distance D2 should preferably be set to 100 to 700 μm.

Next, an example will be described based on the test results.

Fig. 16 is a cross-sectional view showing a radio controlled table according to another example of the present invention.

A watch case 30 has a substantially cylindrical shape, and a glass 32 is attached to a shoulder portion 30a provided on the inner periphery of the upper opening portion in the drawing through a seal gasket 31. Further, a back cover 33 is fixed to the lower opening portion in the drawing by, for example, press fitting, screw threads, or screws.

The back cover 33 shown in fig. 16 is attached to the case band 30 by press-fitting, and the packing 44 is interposed between a rising portion 33a and the inside surface 30c of the case band 30.

Further, the watch case 30 accommodates a movement 34 including a receiver, a CPU, a display driving portion, and the like of the radio-controlled watch, which are shown in fig. 26 described above.

A clock panel 35 and hands 36 serving as a time display section are provided above the movement 34 in the figure. The movement 34 is positioned by abutment of the clock face 35 on the lower surface of the inner projecting portion 30b forming the shoulder portion 30a of the watch case 30 in the drawing. As a result, the movement 34 is inserted between the clock panel 35 and the resin intermediate frame 45 provided on the upper surface of the rising portion 33a of the back cover 33, and is thereby fixed.

Further, a predetermined space is provided between the movement 34 and the back cover 33, and the antenna 37 is provided in the space. The antenna 37 is constituted by a rod-shaped magnetic core piece 38 and a coil 40 wound around the magnetic core piece 38, and is fixed to the lower surface of the movement 34.

In the present example, the case band 30 and the back cover 33 are formed of austenitic stainless steel (e.g., SUS 316L).

Further, according to the test results, the body thickness T1 of the case band 30 was set to 1600 μm, and the distance D1 from the antenna 37 to the inner surface of the case band 30 was set to 2000 μm.

Further, the back cover thickness T2 of the back cover 33 is set to 800 μm, and the distance D2 from the antenna 37 to the inner surface of the back cover 33 is set to 3000 μm.

In the radio-controlled watch having the above-described structure, the CPU in the movement 34 operates the display driving section in accordance with the standard radio waves received by the antenna 37, thereby driving to always correct the pointer 36.

At this time, in the present example, the case band 30 and the back cover 33 are formed of a metal such as stainless steel having a low reception sensitivity as described in example 1, and further, the body thickness, the back cover thickness, and the distance between the antenna and the body and the back cover are set to have values according to the test results, which can be respectively set to the optimum reception sensitivities. Therefore, interference of the resonance phenomenon in the vicinity of the antenna can be reduced, and thus, the reception sensitivity can be improved.

It has been determined from the experiment of example 1 that the gain is improved by about 2 to 3dB if a non-magnetic member having a resistivity of 7.0 μ Ω -cm or less, for example, gold, silver, copper, brass, aluminum, zinc, magnesium or an alloy thereof, is attached to the inner surface of the back cover 33 or the inner surface of the case 30.

Further, hardening treatment such as carburizing treatment may also be performed on the case band 30 or the back cover 33, or both. The reduction in the reception sensitivity caused by performing the hardening process is not seen.

(example 9)

Fig. 17 is a cross-sectional view showing a radio control table according to another example of the present invention.

In this example, the basic structure concerning the shapes of the case band 30 and the back cover 33 and the like is the same as that of example 8. In addition, the materials of the case band 30 and the back cover 33, the body thickness T1 of the case band 30, the distance D1 between the antenna 37 and the case band 30, the back cover thickness T2 of the back cover 33, and the distance D2 between the antenna 37 and the back cover 33 are all different. For this reason, these will be described in detail.

The case band 30 and the back cover 33 according to the present example are formed of titanium. In the wristwatch case of the case 30 and the back cover 33 formed of titanium, assuming a standard corresponding to a high pressure of waterproofness, the body thickness T1 is set to 20000 μm, which is larger than that in example 8, and likewise, the back cover thickness T2 is set to 1000 μm.

However, depending on the relationship between the materials of the case body 30 and the back cover 33, an allowable reception sensitivity can be obtained even if the distance between the antenna 37 and the case body 30 and the back cover 33 is increased. Therefore, the distance D1 between the antenna 37 and the case band 30 is set to 500 μm, and the distance D2 between the antenna 37 and the back cover 33 is set to 400 μm.

Also in the present example, the case band 30 and the back cover 33 are formed of a metal such as titanium having low reception sensitivity as described in example 1. However, the body thickness, the back cover thickness, and the distance between the antenna and the body and the back cover are set to have values according to experimental results, which can respectively obtain the optimal receiving sensitivity. Therefore, interference of the resonance phenomenon in the vicinity of the antenna can be reduced, and thus, the reception sensitivity can be improved.

Also in this example, the same nonmagnetic member as in example 8 described above is attached to the inner surface of the back cover 33 or the inner surface of the case band 30. Thus, the gain can be improved by about 2 to 3 dB.

Further, hardening treatment such as nitriding treatment may also be performed on the case band 30 or the back cover 33, or both of them. The reduction in the reception sensitivity caused by performing the hardening process is not seen.

(example 10)

Fig. 18 is a cross-sectional view showing a radio control table according to another example of the present invention.

In this example, the basic structure concerning the shapes of the case band 30 and the back cover 33 and the like is substantially the same as that of each of examples 8 and 9. And the material of the case band 30 and the back cover 33 are different. For this reason, these will be described in detail.

The case band 30 and the back cover 33 according to the present example are formed of the body portions 30d and 33d composed of a brass material, and mirror-finished, and then, the plating layers 30e and 33e such as Pd are formed on the surface by a wet plating method and thus surface treatment is completed.

The brass material was a non-magnetic member having a resistivity of 7.0 μ Ω -cm or less, which brought the reception sensitivity to the optimum state in the experiment according to example 1, and the integral thickness and the like could be set, and further, the reception sensitivity could be further improved.

The case watch 30 and the back cover 33 according to the present example are the same as those in example 8 except that plating is performed. Further, the body thickness T1 was set to 1600 μm, and the back cover thickness T2 was set to 800 μm.

Further, referring to the distance between the antenna 37 and the case body 30 and the back cover 33, the distance D1 between the antenna 37 and the case body 30 is set to 2000 μm, and the distance D2 between the antenna 37 and the back cover 33 is set to 3000 μm.

The plating layers 30e and 33e of the case body 30 and the back cover 33 are formed by a wet plating method, which will be described below.

To form the base plating layer, first, electroplating is performed on the body portions 30d and 33d under the following conditions:

electroplating bath:

(composition: NaSnO₃·3H₂O 60g/l，CuCN 20g/l，K₂SO₃H10 g/l, KCN (free) 30g/l, KOH 60g/l, Zn (CN)₂ 5g/l)，

The temperature of the tank is 50 ℃,

current density 2.4A/dm²，

pH 12.5，

A precipitation rate of 0.33 μm/min, and

the time is 6 minutes.

Electroplating bath:

electroplating conditions are as follows:

the temperature of the tank is 50 to 55 ℃,

current density 2.0A/dm²，

The current efficiency is 47.8 percent,

the pH value of the mixture is 12.5 to 13,

a precipitation rate of 0.33 μm/min, and

the time is 9 minutes.

By electroplating, a Sn-Cu-Pd alloy plating layer having a thickness of about 3 μm, a hardness (Hv) of about 300, and a density of 9.6g/cm was formed on the base plating layer³。

Then, plating was performed on the Sn-Cu-Pd alloy under the following conditions to form a plating layer for polishing treatment.

Electroplating bath:

(PALLABARRIGHT-SSS (trade name) manufactured by JAPAN PURE CHEMICAL CO., LTD).

Electroplating conditions are as follows:

the temperature of the cell was 55 c,

current density 1.5A/dm²，

pH 7.6，

A precipitation rate of 0.33 μm/min, and

the time is 6 minutes.

9.9g/l of sodium chloride,

0.8g/l of sodium sulfate,

7.1g/l of urea,

0.19ml/l of ammonia water,

sucrose 0.2g/l, and

lactic acid (50%) 0.8 ml/l.

Also in the present example, the case band 30 and the back cover 33 are formed of metal. However, the thickness of the body, the thickness of the back cover, and the distance between the antenna and the body and the back cover are set to have values according to experimental results, which can respectively obtain the optimal receiving sensitivity. Therefore, interference of the resonance phenomenon in the vicinity of the antenna can be reduced, and thus, the reception sensitivity can be improved.

Further, the case band 30 and the back cover 33 are subjected to surface polishing treatment. Thus, corrosion resistance and heat resistance necessary for a watch are provided, and in addition, a white background metallic luster having quality and a high-grade feeling is provided.

Also in examples 8 to 10, if a rising portion is not formed on the back cover 33 in the back cover 33 as shown in fig. 18, but the inner surface is rendered flat, rendering the back cover 33 in a planar two-dimensional shape, it is possible to more reduce the interference of the resonance phenomenon around the antenna 37 and to more improve the reception sensitivity by about 2dB, as compared with the case in which the rising portion is provided.

Further, in order to further reduce the size and thickness of the watch, the distance between the antenna 37 and the watch case 30 or the back cover 33 may be set to zero in consideration of the directivity of the antenna 37.

Further, in consideration of the directivity of the antenna 37, the antenna 37 may be set in such a manner that: the outer surface of the antenna 37 and the inner surface of the case band 30 or the inner surface of the back cover 33 are parallel to each other, or one of the end surfaces of the antenna 37 may be disposed in a direction substantially perpendicular to the inner surface of the back cover 33 in the vertically raised state.

Although the wristwatch cases according to respective examples 8 to 10 are constituted by the case band 30 and the back cover 33, the wristwatch cases in which a bezel or a ring is provided in an upper portion of the case band 30 can also be used.

Further, in this wristwatch case, if any one of the body, the bezel and the back cover is formed of a non-magnetic member (to be described later), the receiving sensitivity can be more improved. By providing the bezel separately from the body, the reception sensitivity can be improved.

Further, in addition to the entire structure being constituted by the non-magnetic member, even if only a part of the main body, the bezel, and the back cover is formed by the non-magnetic member, the reception sensitivity can be improved. In this case, it is effective that only a part on which the antenna 37 protrudes in parallel or an opposite part of the end of the antenna 37 is formed of a non-magnetic member, which is preferable.

Further, instead of using only one type of metal and non-magnetic member, a combination of a plurality of metal and non-magnetic members may be used.

As for the materials selected for the case band 30 and the back cover 33, in the same manner as in the above-described test, an antenna for test was provided in the body and the back cover for test, which were formed of the materials used, and the test of transmitting a signal from the transmitting antenna provided at a predetermined position was carried out.

In the case of gold, silver, copper, brass, aluminum, zinc, magnesium, their alloys or tungsten carbide, the results of the tests showed that the gain was improved by 2 to 3dB (decibel) compared with the case of stainless steel, titanium alloy and tantalum carbide. Further, it was also confirmed from the same experiment that the reception sensitivity of the antenna provided on the inner side of the case can be improved not only in the case in which the case is formed of a metal having a high reception sensitivity but also in the case in which the case is formed of a metal having a reduced reception sensitivity with the metal having a high reception sensitivity provided in a part thereof.

Further, as a result of comparing the resistivity of the metals used for the test, it has been found that the metals having a resistivity of 7 μ Ω -Cm or less can maintain high reception sensitivity. As a result, it has been found that a watch case using metal can have improved reception sensitivity if the whole of the watch case or a part thereof is formed of a nonmagnetic member such as gold, silver, copper, brass, aluminum, zinc, magnesium, or an alloy thereof and a hard metal.

Further, it was confirmed that if the wristwatch case was formed of a metal having high reception sensitivity, such as stainless steel, titanium alloy or tantalum carbide, the appearance quality of these materials was excellent, and a part of them had a portion formed of a non-magnetic member, the reception sensitivity could be improved.

Referring to the materials of the body, the back cover, etc., further, a resin member is used for the bezel, etc., so as to appear vivid, or a resin garnish is attached to the side surface of the body for the purpose of decoration. Obviously, such a structure using a metal in the basic part is included in the scope of the metal watch case according to the present invention.

(example 11)

Fig. 19 is a sectional view showing a radio controlled watch according to another example of the present invention, and fig. 20 is a plan view showing the magnetism preventing plate 38 shown in fig. 19, which is a view seen in the direction of the back cover.

A wristwatch case 12 according to the present example is constituted by a case band 14, a back cover 16 and a glass 18.

The case band 14 has a substantially cylindrical shape, and the glass 18 is attached to a shoulder portion 14a provided on the inner peripheral edge of the upper opening portion in the drawing through a seal gasket 20. Further, a back cover 16 is fixed to the lower opening portion in the drawings by a method such as press-fitting, screwing or screwing.

Back cover 16 shown in fig. 19 is attached to case band 14 by press-fitting. A seal 22 is interposed between a rising portion 16a and an inner side surface 14c of the case band 14.

In addition, the watch case 14 houses a movement 24 including a receiver, a CPU, a display driving portion, and the like of the radio-controlled watch. A clock panel 26 and hands 28, which serve as a time display section, are provided above the movement 24 in the drawing.

The movement 24 is positioned on the lower surface of the internal projecting portion 14b by abutment of the face plate 26, in the drawing, the projecting portion 14b forming the shoulder portion 14a of the watch case 14. The movement 24 is inserted between the clock panel 26 and a resin intermediate frame 30 provided on the upper surface of the rising portion 16a of the back cover 16, and is fixed thereby.

Further, a predetermined space is provided between the movement 24 and the back cover 16, and an antenna 32 is provided in the space.

The antenna 32 is constituted by a rod-shaped magnetic core member 34, the magnetic core member 34 is formed of a ferrite material, and a coil 36 is wound around the magnetic core member 34 and fixed to the lower surface of the core 24.

Further, in the present example, the magnetism preventing plate 38 is provided in the space between the movement 24 and the back cover 16.

The magnetism preventing plate 38 is formed of ferrite-type stainless steel (for example, SUS430), and has a circular planar shape so as to approximate the planar shape of the movement 24, a sectional shape thereof being an upward U-shape, and a raised portion 38a at an outer peripheral portion (as shown in a plan view viewed in the direction of the back cover in fig. 20).

In the magnetism preventing plate 38 according to the present example, the tip end portion of the rising portion 38a is fixed to the movement 24 by a slope or a screw.

Further, the magnetism preventing plate 38 is provided with an opening portion 38 b. When the magnetism preventing plate 38 is attached to the movement 24, the opening portion 38b is provided to be positioned at a portion (an opposing portion) opposing the antenna 32.

In this example, the antenna 32 is disposed at a corner of the lower surface of the movement 24 so that the axis of the core member 34 is rotated in a direction orthogonal to the double-sided direction of the watch.

For this reason, the opening portion 38b of the magnetism preventing plate 38 is provided at a position where the antenna protrudes onto the magnetism preventing plate 38 in a direction parallel to the plane of the antenna 32 including the axis of the magnetic core member 34. Further, the inner dimension of the opening portion 38b is set to be equal to or slightly larger than the outer dimension of the antenna 32.

In the radio-controlled watch having the above-described structure, the CPU in the movement 24 operates the display driving section in accordance with the standard radio waves received by the antenna 32, thereby driving to always correct the pointer 28.

At this time, in this example, the movement 24 is surrounded by the magnetism preventing plate 38. Therefore, the driving operation of the pointer is not affected by the external magnetism. Further, the magnetism preventing plate 38 is provided with an opening portion 38 b. Thus, the antenna 32 is directed toward the back cover 16 so that radio signals can be received without being shielded by the magnetic shielding plate 38.

(example 12)

Fig. 21 is a cross-sectional view showing a radio controlled table according to another example of the present invention.

In this example, the basic structure concerning the wristwatch case 12, the magnetism preventing plate 38, and the like is the same as that of example 1, and the relationship between the magnetism preventing plate 38 and the antenna 32 is different from that in example 11. For this reason, the differences will be described in detail.

In this example, a magnetism preventing plate 38 formed of pure iron is assembled into a lower portion of the movement 24 so as to be in contact with a lower surface of the movement 24. At this time, the antenna 32 protrudes from the opening portion 38b of the magnetism preventing plate 38 in a direction toward the back cover 16, and is positioned on the outer side of the magnetism preventing plate 38.

Therefore, the antenna 32 is positioned at a place not surrounded by the antimagnetic plate 38. Thus, radio waves can be received without being affected by the magnetism prevention plate 38.

In this example, the magnetic shield 38 and the movement 24 are arranged to contact on a number of components. Therefore, the antimagnetic plate 38 can also be bonded and fixed to the movement 24 with an adhesive.

(example 13)

Fig. 22 is a cross-sectional view showing a radio controlled table according to another example of the present invention.

In this example, the basic structure of the positional relationship such as between the watch case 12 or the magnetism preventing plate 38 and the antenna 32 is the same as that of example 11, and the arrangement of the nonmagnetic member 40 is different from that of example 11. For this reason, the non-magnetic member 40 will be described in detail.

The non-magnetic member 40 is formed of a metal material having a resistivity of 7.0 μ Ω -Cm or less, for example, gold, silver, copper, brass, aluminum, magnesium, zinc, or an alloy thereof, in this example, a plate-shaped copper material.

Further, the magnetism preventive plate 38 is formed of YUS material (a clad material) and positioned between the movement 24 and the back cover 16 in the same manner as in example 11. Further, an antenna 32 is provided positioned on the movement 24 away from the magnetic shield 38.

The non-magnetic member 40 is disposed between the antimagnetic plate 38 and the antenna 32 as described above, in this example and attached to the inner surface of the antimagnetic plate 38 facing the antenna 32.

Therefore, the non-magnetic member 40 is disposed opposite the antenna 32, or the non-magnetic member 40 is disposed near the antenna. Therefore, it has been confirmed from experiments that the reception gain of the radio signal can be improved by about 2 to 3 dB.

Further, the non-magnetic member 40 according to the present example is provided with an opening portion 40b at a position corresponding to the opening portion 38b of the magnetism preventing plate 38. Further, the non-magnetic member 40 has a structure that does not block reception of radio signals in the same manner as the magnetism preventive plate 38.

Further, in order to prevent corrosion, surface treatment such as plating on the nonmagnetic member 40 may be performed. No reduction in reception sensitivity due to the execution of the surface treatment was seen.

(example 14)

Fig. 23 is a cross-sectional view showing a radio controlled table according to another example of the present invention.

In this example, the basic structure of the positional relationship such as between the watch case 12 or the magnetism preventing plate 38 and the antenna 32 is the same as that of example 11, and further, the nonmagnetic member 42 is provided in the opening portion 38b of the magnetism preventing plate 38, which is different from example 11. For this reason, the differences will be described in detail.

The nonmagnetic member 42 is formed of a metal material having a resistivity of 7.0 μ Ω -Cm or less, which is the same as that of example 13, in this example, a brass material.

Further, the magnetism preventing plate 38 according to the present example is formed of ferrite-type stainless steel (e.g., SUS 430). Further, a magnetic shield 38 is provided between the movement 24 and the back cover 16 in the same manner as in the above example 11, and has an opening portion 38b at a position opposed to the antenna 32 attached to the lower surface of the movement 24.

The non-magnetic member 42 is attached to the opening portion 38b of the magnetism preventing plate 38, opposite to the antenna 32, by caulking, soldering, adhesive, or the like. When the non-magnetic member 42 is thus provided, interference of a resonance phenomenon near the antenna can be reduced, and thus, the reception sensitivity can be improved. Therefore, the gain of radio signal reception can be improved by about 2 to 3 dB.

Further, a surface treatment such as plating may also be performed on the nonmagnetic member 42 in the same manner as the nonmagnetic member 40 according to example 13. In this wristwatch case, the reduction in the reception sensitivity caused by performing the surface treatment was not seen.

(example 15)

Fig. 24 is a sectional view showing a radio controlled watch according to another example of the present invention, and fig. 25 is a plan view showing a magnetism preventing plate 38 shown in fig. 24, which is a view seen in the direction of a back cover.

In this example, the basic structure of the positional relationship between the antenna 32 and the like such as the case 12 or the antimagnetic plate 38 is the same as that of example 1. Further, a click is provided on the magnetism preventing plate 38, and fixing of the magnetism preventing plate 38 is performed by being inserted between the upper surface of the rising portion 16a of a screw type back cover 16 and the lower surface of the movement 24, which is different from example 11. For this reason, the differences will be described in detail.

The antimagnetic plate 38 is provided with a rising portion 38a erected to surround the movement 24.

In this example, a groove portion 38c is provided on a part of the rising portion 38 a. Further, the groove portion 38c is fitted in the inner end of the side pipe 44 passing through the case band 14, whereby the rotation of the magnetism preventing plate 38 is prevented to easily achieve positioning.

Since the back cover 16 is fixed to the case band 14 with a screw, it is assumed that the magnetism preventing plate 38 provided on the upper surface of the rising portion 16a of the back cover 16 is also rotatable. Since the side pipe 44 is fitted in the groove portion 38c as described above, the rotation of the magnetism preventing plate 38 can also be prevented.

Case 12 of any material suitable for a radio-controlled watch, for example, stainless steel, plastic, and the like, may also be used, and case 12 is constituted by case 14, back cover 16, and the like according to each of examples 11 to 15.

Further, in each of examples 11 to 15, the antenna 32 is provided on a corner of the lower surface of the movement 24 so that the axis of the core piece 34 is rotatable in a direction orthogonal to the double-sided direction of the watch.

In the case of a longitudinal section visible from the case in consideration of the directivity of the antenna 32, one of the end faces may also be provided substantially parallel to the inner surface of the back cover 16 of the case (see fig. 30(B)) in the axial direction of the antenna 32. Further, the outer side surface of the antenna 32 may be provided substantially perpendicularly to the inner surface of the back cover 16 of the watch case (see fig. 30(B)) so as to provide the antenna 32 in a longitudinally erected state (in the vertical direction).

Further, in the wristwatch case in which the case band 14 has a rectangular shape (seen in plan view), for example, the inner surface of the case band 14 of the wristwatch case and the outer side surface of the antenna 32 (i.e., the outer side surface in the transverse direction of the antenna) may also be provided substantially in parallel with each other (seen in plan view), thereby providing the antenna 32 in a longitudinally erected state (in the vertical direction) (see fig. 30 (a)).

In the case of the longitudinal section visible from the case in consideration of the directivity of the antenna 32, one of the end faces may be provided substantially perpendicularly to the inner surface of the back cover 16 of the case (see fig. 30(D)) in the axial direction of the antenna 32. Further, the inner surface of the case 14 of the watch case and the outer side surface of the antenna 32 (see fig. 30(C)) may be disposed substantially in parallel (as viewed in plan view) so as to provide a state in which the antenna 32 is overlapped in the horizontal direction.

Further, in the case of the watch case 14 having a rectangular shape (seen in plan view), for example, the inner surface of the back cover 16 of the case and the outer side surface of the antenna 32 (i.e., the outer side surface in the longitudinal direction of the antenna) may also be provided substantially in parallel with each other (see fig. 30(D)), thereby providing the antenna 32 in an overlapped state in the horizontal direction.

In this watch case, the opening portion 38b of the magnetism preventing plate 38 may be formed with respect to the entire shape of the antenna 32 as in the above-described examples 11 to 15, or may be formed on the rising portion 38a so as to be opposed to the end of the antenna 32.

Further, instead of using only one type of material among the materials for the magnetism prevention plate 38 and the nonmagnetic members 40 and 42, a plurality of types of metal and nonmagnetic members may be used in combination.

Referring to the selection of the metal for the nonmagnetic members 40 and 42, the nonmagnetic member formed of the material used and the antenna for the test were disposed in a watch case for the test, and a test for transmitting a signal from a transmitting antenna disposed at a predetermined position was conducted to make the selection (see the test according to example 1).

As a result of this test, in the watch case of gold, silver, copper, brass, aluminum, magnesium, zinc or their alloys, the gain can be increased by 2 to 3dB (decibel) higher than that of the watch case of titanium, titanium alloy, stainless steel and tantalum carbide.

Further, from the results of the resistivity comparison of the metals used for the test (see the test according to example 1), it is apparent that the metals having a resistivity of 7.0 μ Ω -Cm or less can maintain a high reception sensitivity.

As a result, it is apparent that if the non-magnetic members 40 and 42 are formed of a material such as gold, silver, copper, brass, aluminum, magnesium, zinc, or an alloy thereof, the receiving sensitivity can be improved also when the magnetism preventing plate 38 is used.

According to each of examples 11 to 15, a magnetism prevention plate is provided in a radio-controlled watch to protect the watch device from external magnetism. Therefore, the accuracy of time display can be improved.

Further, even if the magnetism preventing plate is provided, the deterioration of the radio receiving performance for the time information can be significantly slowed down because the opening portion and the non-magnetic member are provided on the magnetism preventing plate. Thus, a antimagnetic structure can be implemented without affecting the original performance of the radio-controlled watch.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto. Although the case band, back cover and bezel in the wristwatch case of the present invention have been described, the present invention is also applicable to other watches having a case such as a ring. Furthermore, the invention is applicable not only to radio-controlled watches but also to wall clocks, desk clocks, alarm clocks, etc. Accordingly, various changes may be made without departing from the scope of the invention.

(Effect of the invention)

According to the invention, a non-magnetic member having a resistivity of 7.0 [ mu ] omega-Cm or less is provided in a watch case housing an antenna and a watch device. Therefore, interference of a resonance phenomenon in the vicinity of the antenna caused by the metal material can be reduced. Therefore, sufficient reception sensitivity can be obtained also in the metal wristwatch case.

By using a nonmagnetic member having a resistivity of 7.0 μ Ω -Cm or less as a nonmagnetic member fixed to a case of a radio-controlled watch, for example, inner surfaces of a case body and a back cover, it is possible to use a metal having excellent appearance quality, for example, titanium alloy, stainless steel or tantalum carbide, which has a low reception sensitivity, a low frequency selectivity and a high resistivity like the case body, for example, the case body and the back cover, without sacrificing the reception sensitivity. Therefore, the function of the case mechanism and the appearance can be improved.

Further, according to the present invention, a part of the wristwatch case, for example, a part of the case band, the back cover, the bezel and the like, or at least one of them is formed of a non-magnetic member having a resistivity of 7.0 μ Ω -Cm or less. Therefore, interference of a resonance phenomenon near the antenna caused by the metal material can be reduced by the non-magnetic member. Therefore, sufficient reception sensitivity can be obtained also in the metal wristwatch case.

If a non-magnetic member having a resistivity of 7.0 μ Ω -Cm or less is used for at least one of a part of a watch case, for example, a part of a watch case, a back cover, a bezel, etc., or the above-mentioned part of a radio-controlled watch, therefore, a metal having a high appearance quality, for example, titanium, a titanium alloy, stainless steel, or tantalum carbide, which has a low reception sensitivity, a low frequency selectivity, and a high resistivity as that of a part of the watch case other than the part of the watch case formed of the non-magnetic member can be used without sacrificing the reception sensitivity. Therefore, the function of the case mechanism and the appearance can be improved.

Further, a surface polishing treatment is performed on the surface of the case portion formed of the non-magnetic member. Therefore, it is possible to design and manufacture a watch case having corrosion resistance, heat resistance, mechanical strength, etc., and having a color feeling such as a metallic color, which has a high-class feeling and high appearance quality, for example, a case band, a back cover, a bezel, etc., in the same manner as a general watch which is not a radio-controlled watch. Thus, variations in the design of the watch case in a radio controlled watch can be improved to be comparable to a normal watch.

According to the present invention, the wristwatch case is made of a metal, and the distances between the antenna and the wristwatch case, that is, the body thickness T1 of the case body of the wristwatch case, the back cover thickness T2 of the back cover of the wristwatch case, the gap D1 from the inner surface of the wristwatch case to the antenna, and the gap D2 from the inner surface of the back cover to the antenna, are set in accordance with the reception sensitivity. Therefore, interference of a resonance phenomenon in the vicinity of the antenna caused by the metal material can be reduced. Therefore, the receiving sensitivity can be improved also in the metal wristwatch case. Therefore, a metal having high appearance quality, such as titanium, titanium alloy, stainless steel or tantalum carbide, which has a low reception sensitivity, a low frequency selectivity and a high specific resistance as in the case of a watch, such as a watch case, a back cover, a bezel, etc., can be used without sacrificing the reception sensitivity. Therefore, the function of the case mechanism and the appearance can be improved.

Further, according to the present invention, the antimagnetic plate provided in the case has an opening portion in a portion opposed to the antenna. Therefore, the antenna can receive radio waves through the opening portion without the influence of the antimagnetic plate. Therefore, the watch device can be protected from external magnetism without degrading the reception characteristics of radio waves in the radio-controlled watch. Therefore, accuracy can be improved in the table without affecting the driving operation of the pointer.

The case for housing the antenna is formed of a material having a non-conductive property or a low resistivity, and an exterior member attached to the outside of the case, and particularly, the exterior member for covering the outside surface of the case is conductive, for example, a metal.

Compared to a case in which the case itself for accommodating the antenna is formed of a conductive material, therefore, the distance between the antenna and the conductive exterior member can be increased. Therefore, it is difficult to cause failure of antenna reception. Therefore, the antenna can receive radio waves well, and thus, the reception performance and the accuracy of the watch can be improved.

By means of the electrically conductive outer part, such as a metal, it is furthermore possible to give the radio-controlled watch a metallic appearance. Thus, the visual perception appears to be that the case is formed of a solid metal. Therefore, by using a non-conductive material such as synthetic resin for the watch case, deterioration of the high-class feeling and the delicate appearance can be prevented. Thus, the present invention can produce many significant and unique functions and effects, which are excellent.

Claims

1. A radio controlled watch comprising:

an antenna for receiving a radio wave including time information;

a timepiece means for causing the display section to display time information of a current time of the radio wave received by the antenna; and

a case for housing the antenna and the watch device,

wherein the watch case is made of metal,

the wristwatch case includes a case band and a back cover attached and fixed to the case band,

the body thickness T1 of the watch case ranges from 300 μm to 5000 μm.

2. A radio controlled watch as claimed in claim 1, characterised in that the watch case and the antenna are set in such a way that: the body thickness T1 of the case body of the watch case ranges from 500 μm to 2000 μm.

3. A radio controlled watch as claimed in claim 1 or 2, characterised in that the watch case and the antenna are set in such a way that: the gap D1 from the inner surface of the case of the watch case to the antenna is in the range of 0 to 40000 μm.

4. A radio controlled watch as claimed in claim 1 or 2, characterised in that the watch case and the antenna are set in such a way that: the gap D1 from the inner surface of the case of the watch case to the antenna is in the range of 500 μm to 10000 μm.

5. A radio controlled watch as claimed in claim 1 or 2, characterised in that the case and the antenna are configured to: the back cover thickness T2 of the back cover of the watch case is in the range of 100 μm to 5000 μm.

6. A radio controlled watch as claimed in claim 1 or 2, characterised in that the case and the antenna are configured to: the back cover thickness T2 of the back cover of the watch case is in the range of 300 μm to 2000 μm.

7. A radio controlled watch as claimed in claim 1 or 2, characterised in that the watch case and the antenna are set in such a way that: the gap D2 from the inner surface of the back cover of the watch case to the antenna is in the range of 0 to 5000 μm.

8. A radio controlled watch as claimed in claim 1 or 2, characterised in that the watch case and the antenna are set in such a way that: the gap D2 from the inner surface of the back cover of the watch case to the antenna is in the range of 100 to 700 μm.

9. The radio-controlled watch as claimed in claim 1 or 2, characterized in that the watch case is formed of at least one material selected from the group consisting of: titanium, titanium alloys, stainless steel, tungsten carbide, and tantalum carbide.

10. The radio-controlled watch as claimed in claim 1 or 2, characterized in that the watch case is formed of at least one material selected from the group consisting of: gold, silver, copper, brass, aluminum, magnesium, zinc, and alloys thereof.

11. Radio controlled watch as claimed in claim 1 or 2, characterized in that at least one of the watch case and the back cover of the watch case is subjected to a surface treatment and/or a hardening treatment.

12. A radio controlled watch as claimed in claim 1 or 2, characterised in that the back cover of the watch case is two-dimensional planar.

13. A radio controlled watch comprising:

an antenna for receiving a radio wave including time information;

a timepiece means for causing the display section to display time information of a current time of the radio wave received by the antenna;

a magnetic shielding plate for shielding external magnetic influence; and

a case for accommodating the antenna, the watch device and the antimagnetic plate,

14. The radio-controlled watch of claim 13, wherein the antenna is constituted by a magnetic core member and a coil wound around the magnetic core member by a plurality of turns, and

an opening portion is provided in a position on the antimagnetic plate where the antenna protrudes in parallel along at least one plane including the axis of the magnetic core member.

15. The radio-controlled watch of claim 13, wherein the antenna is constituted by a magnetic core member and a coil wound around the magnetic core member by a plurality of turns, and

16. The radio-controlled watch of claim 13, wherein the antenna is positioned on the outside of the antimagnetic plate.

17. The radio-controlled watch of claim 13, wherein the antimagnetic plate is located on the watch device side between the watch device and the back cover.

18. The radio-controlled watch of claim 13, wherein the antimagnetic plate is located on the back cover side between the watch device and the back cover.