HK1081674B - Radio wave wristwatch - Google Patents

Description

Radio-wave watch

The present application is a divisional application filed by the applicant at 27.6.2002 under application number 028037111(PCT/JP 02/06506).

Technical Field

The present invention relates to a Radio-wave wristwatch (Radio wristwatch/Radio christwatch) having a built-in receiving antenna in a case. Specifically, it is a radio wristwatch having a built-in antenna, capable of receiving a radio wave time signal, having high sensitivity, and employing a metal case having a weak radio wave penetration ability.

Background

Generally, most consumers believe that a metal case is preferred for watches. In elderly populations if divided by age, in japan and europe one may often find that many consumers have this taste if divided by geographical location.

For a radio wave wristwatch with a built-in antenna, plastics and ceramic materials that can be penetrated by radio waves are generally used. If metal such as stainless steel is used as the material of the case of this wristwatch, the radio wave time signal will not sufficiently penetrate the case. Therefore, the intended function of receiving radio waves cannot be realized. If plastic materials are used for the watch case, purchasers of such radio-wave watches with built-in antennas will be dominated by the young. This is primarily because they are not very sensitive to the luxury of the watch's appearance. This type of watch is practically scarcely sold in the elderly population. Moreover, if the case is made of ceramic material, the sales is sharply reduced because of the high price.

On the other hand, in a radio-wave wristwatch equipped with an external antenna, since the external antenna is mounted on a specially designed plastic case or on a leather band so that the receiving antenna can be mounted outside the case, the case itself with the movement can be made of metal. However, such a radio-wave wristwatch equipped with an external antenna is not so compact in appearance and lacks flexibility, and the connection structure between the antenna and the watch core becomes complicated, so that it is difficult to expand the sales.

Therefore, the inventors have conducted extensive studies to develop a radio wave wristwatch with a built-in antenna capable of receiving a radio wave time signal and having high sensitivity while employing a metal wristwatch case having a low penetration ability. The development process is as follows.

Fig. 6 is a sectional view showing the structural characteristics of a conventional metallic wristwatch case for a general wristwatch (a general wristwatch other than a radio wave wristwatch).

As shown in fig. 6, this metal wristwatch case 101 is composed of three elements overlapped with each other. These three elements are a metal bezel 102 for forming the exterior of a watch case, an annular metal window frame (also commonly referred to as a "watch bezel") 104 attached to the surface of the metal bezel 102 and constituting the edge of a transparent window plate 103, and a metal back cover 105 attached to the back of the metal bezel 102.

Inside the metal watch case 101, a metal dial 106 is mounted. The metal dial is opposed to the transparent window plate 103, and the watch movement 107 is housed in a space 108 formed by the metal dial 106 and the metal back cover 105.

For example, the metal raceway 102 shown in FIG. 6 is made of SUS304 stainless steel having a thickness of 4mm, an inner diameter of 32mm, and a height D1 of 6 mm. For example, a glass material having a thickness of 1mm and a diameter of 30mm is used as the transparent window plate 103; SUS304 stainless steel having a thickness of 4mm, an inner diameter of 28mm and a height of 3mm was used as the annular metal window frame 104. For example, SUS304 stainless steel having a thickness of 2mm and a diameter of 36mm can be used as the metal rear cover 105. For another example, a metal material Bs having a thickness of 0.6mm and a diameter of 30mm can be used as the metal dial 106. As another example, a conventional watch movement of 26mm diameter and 5mm height may be used as movement 107.

If the conventional wristwatch core 107 is simply replaced with a radio wave wristwatch core with a built-in antenna simply according to the configuration shown in fig. 6, it will be difficult for the radio wave wristwatch core to receive the radio wave time signal. The reason for this is that the movement of the radio-wave wristwatch is completely enclosed by the metal dial 106 located on the upper side, the metal back cover 105 located on the lower side, and the metal bezel 102 located on the periphery and relatively thick.

Therefore, the inventors have tried to replace the metal dial 106 with a dial made of a radio wave-permeable material (e.g., glass or plastic) and to replace the metal back cover 105 with a back cover made of a radio wave-permeable material (e.g., glass or plastic). Since the radio wave shielding members at the upper and lower ends of the moving part are eliminated, the radio wave time signal receiving sensitivity is significantly improved. However, the radio wave time signal reception sensitivity has not yet reached a practical level.

Next, the inventors turned their attention to the radio wave shielding member located at the side of the watch core 107, and attempted to reduce the thickness of the metal bezel 102. However, since the metal bezel 102 must maintain the strength of the watch case and be used for mounting the operation button penetrating the metal bezel 102, the reduction in thickness is limited. Therefore, although the radio wave time signal reception sensitivity is improved to some extent, it has not yet reached a practical level.

Disclosure of Invention

The present invention has been made in the light of the above-described technical background. Accordingly, an object of the present invention is to produce a radio-wave wristwatch having a metallic appearance like a general wristwatch by improving the radio-wave transmitting ability in the vertical direction and around the watch core while achieving a desired level of strength and thickness of a metal bezel constituting the watch case.

Another object of the present invention is to provide a radio-wave wristwatch having a metallic appearance and being manufactured at low cost.

The invention has other objects and advantages that will be apparent to those skilled in the art from the following description.

A radio wave wristwatch according to the present invention has a case constituted by three elements in a lap joint manner: the three elements are respectively an annular metal seat ring, an annular metal window frame which is arranged on the surface of the metal seat ring and forms the edge of a transparent window plate, and an annular metal rear cover seat ring which is arranged on the back of the metal seat ring and forms the edge of a non-metal rear cover plate. The term "annular" as used herein in describing the metal seat ring includes various shapes such as circular, square, elliptical, etc. Also, in practice, the bezel is usually provided with a locking element on the outside for mounting the wristband, buttons and elements projecting outwardly from the bezel. Thus, the term "annular" includes all such irregular annuli.

Inside the watch case, a non-metallic dial is disposed at a position opposite to the transparent window plate. The watch core with the built-in antenna is arranged between the non-metal dial and the non-metal back cover. As known to those skilled in the art, a watch movement with a built-in antenna is composed of a receiving antenna, a printed circuit board, a battery, a gear mechanism and other elements necessary for manufacturing a radio-wave wristwatch. As a receiving antenna, a ferrite bar antenna is generally manufactured by winding a coil around a ferrite core having a square bar shape. Watch movement with built-in antenna is sometimes housed in a plastic case formed with a thin-walled part mounted on a thin annular plate. In this case, the side of the receiving antenna is generally exposed outside the housing to improve the signal receiving sensitivity. The height of the watch core with the built-in antenna depends on the design idea but is usually about the thickness of the receiving antenna. That is, the minimum height of the watch core depends on the thickness of the printed circuit board and the gear mechanism stacked together. On the other hand, from the viewpoint of improving the signal reception sensitivity by enlarging the cross-sectional area of the bar, it is preferable to make the bar antenna as thick as possible. Therefore, in practice, the thickness of the printed circuit board and the gear mechanism stacked together is taken into consideration when designing the thickness of the ferromagnetic rod. In the following, the height of the watch core with the built-in antenna is to be understood directly as a synonym for the thickness of the receiving antenna.

The annular metal window frame and/or the annular metal back cover seat ring are provided with an extension part which can extend for a certain length towards the metal seat ring.

As used herein, "and/or" includes three cases: 1) the annular metal window frame extends towards the metal seat ring; 2) the metal back cover seat ring extends towards the metal seat ring; 3) the annular metal window frame extends in the direction of the metal seat ring, and the annular metal rear cover seat ring also extends in the direction of the metal seat ring.

Thus, inside the watch case, the outer ring of the watch movement with the internal antenna, arranged between the non-metallic dial and the non-metallic back cover, is enclosed, so that this area is vertically separated by the metal bezel and the extension of the annular metal window frame and/or the extension of the annular metal back cover bezel.

Here, "enclosed so that the region is vertically divided" means that, although the entire outer ring of the watch core is uniformly enclosed in a conventional manner without a gap as shown in fig. 1(a), in the present invention, as shown in fig. 1(b), 1(c) and 1(d) which are slightly exaggerated, it has a portion enclosed by one metal bezel 300 and a portion enclosed by an extension L1 under the annular metal window frame 301 or an extension L2 on the metal back bezel 302.

Fig. 1(a) shows a case structure of a general wristwatch. In this figure, reference numeral 200 denotes a metal bezel, 201 denotes an annular metal window frame, 202 denotes a metal back cover, 203 denotes a watch core of a general watch, and 205 denotes a metal dial.

In fig. 1(b), 1(c) and 1(d), each of the figures shows a typical case structure of a radio wave wristwatch designed according to the present invention. In these figures, reference numeral 300 denotes a metal bezel, 301 denotes an annular metal window frame, 302 denotes a metal back cover bezel, 303 denotes a radio wave watch movement with a built-in antenna, 304 denotes a transparent window plate, 305 denotes a non-metal dial, 306 denotes a non-metal back cover, L1 denotes an annular metal window frame lower extension, and L2 denotes a metal back cover bezel upper extension.

Specifically, as shown in fig. 1(b), 1(c) and 1(d), the following three enclosure embodiments can be designed according to the arrangement of the above-described extension portions L1 and L2.

The first embodiment is a wristwatch case characterized in that only the annular metal window frame 301 is extended downward to form a lower extension L1, as shown in fig. 1 (b). If the height of the whole watch case is kept constant, the height of the metal bezel 300 is lowered accordingly. In this case, the lower wider region of the outer band of the watch core 303 will be surrounded by the metal bezel 300, while the upper narrower region will be surrounded by the lower extension L1 of the annular metal window frame 301.

A second embodiment is a watch case characterized in that only the metal back cover bezel 302 is extended upward to form an upper extension L2, as shown in fig. 1 (d). Also in this embodiment, if the height of the whole case is kept constant, the height of the metal bezel 300 is lowered accordingly. In this case, the upper wider region of the outer band of the watch core 303 will be surrounded by the metal bezel 300, while the lower narrower region will be surrounded by the upper extension L2 of the annular metal back cover bezel 302.

A third embodiment is a watch case characterized in that not only the annular metal window frame 301 is extended downward to form a lower extension L1, but also the metal back cover bezel 302 is extended upward to form an upper extension L2, as shown in fig. 1 (c). Also in this embodiment, if the height of the whole case is kept constant, the height of the metal bezel 300 is lowered accordingly. In this case, the wider region of the middle of the outer band of the watch core 303 will be surrounded by the metal bezel 300, while the narrower region of the upper part will be surrounded by the lower extension L1 of the annular metal window frame 301 and the narrower region of the lower part will be surrounded by the upper extension L2 of the annular metal back cover bezel 302.

From another point of view, the radio-wave wristwatch case, designed according to the invention, is composed of three elements in an overlapping manner: these three elements are a metallic bezel 300, an annular metallic window frame that is located on the upper surface of the metallic bezel 300 and that becomes the edge of a transparent window panel 304, and a metallic back cover bezel 302 that is located on the lower surface of the metallic bezel 300 and that forms a non-metallic back cover 306.

In the case of a wristwatch, a non-metallic dial 305 is mounted in a position opposite to a transparent window plate 304, and a watch core 303 with a built-in antenna is housed between the non-metallic dial 305 and a non-metallic back cover 306.

In determining the dimensional relationship between the metal bezel 300 and the watch core 303 with a built-in antenna, the height D1 (see fig. 2) of the metal bezel 300 should be made smaller than the height D2 (see fig. 2) of the watch core 303 with a built-in antenna, and the upper and lower outer rings of the watch core 303 with a built-in antenna extending in the vertical direction from the metal bezel 300 should be surrounded by the lower extension L1 of the annular metal window frame 301 and the upper extension L2 of the metal back cover bezel 302.

Here, the thickness of metal bezel 300 forming the outline of the watch case, lower extension L of annular metal window frame 301 on the upper surface of metal bezel 300, and upper extension L2 of metal back cover bezel 302 on the back surface of the metal bezel should be compared. Since the metal bezel 300 is required to maintain the strength of the watch case and the operation buttons are inserted into the metal bezel 300, it is difficult to greatly reduce the thickness of the metal bezel 300. Thus, the thickness of the lower extension L1 of the annular metal window frame 301 and the upper extension L2 of the metal back cover bezel 302 can be significantly reduced, since these extensions L1 and L2 are not required to have such high strength. Therefore, the thicknesses of these extension portions L1 and L2 can be appropriately reduced as compared with the thickness of the race 300. In this way, the radio wave penetration ability of the entire outer ring of the watch core 303 can be improved, thereby bringing the radio wave time signal reception sensitivity to a level required for practical use of the radio wave wristwatch.

In the preferred embodiment of the present invention, the material of the metal seat ring 300 is a non-magnetic metal or a weakly magnetic metal. Such as SUS, Ti, Bs, Al, titanium alloy, aluminum alloy, etc., are included in the group of metals. According to the above configuration, the radio wave penetration ability is also improved by selecting appropriate material characteristics.

In a preferred embodiment of the invention, the material of the annular metal window frame 301 is a non-magnetic metal or a weakly magnetic metal. Such as SUS, Ti, Bs, Al, titanium alloy, aluminum alloy, etc., are included in the group of metals. According to the above configuration, the radio wave penetration ability is also improved by selecting appropriate material characteristics.

In a preferred embodiment of the present invention, the material of the metal back cover bezel 302 is a non-magnetic metal or a weakly magnetic metal. Such as SUS, Ti, Bs, Al, titanium alloy, aluminum alloy, etc., are included in the group of metals. According to the above configuration, the radio wave penetration ability is also improved by selecting appropriate material characteristics.

In a preferred embodiment of the present invention, the material of the non-metallic dial 305 is plastic or glass. According to the above configuration, the non-metallic dial does not shield radio waves.

In a preferred embodiment of the present invention, the material of the non-metallic back cover 306 is plastic or glass. According to the above configuration, the non-metallic back cover does not shield radio waves.

In a preferred embodiment of the invention, the metal bezel 300 has a thickness of 2.0 to 3.0mm, and the annular metal window frame 301 and the metal back cover bezel 302 have a thickness of 0.5mm or less than the thickness of the metal bezel 300. With this configuration, the radio wave penetration ability of the annular metal window frame 301 and the metal back cover bezel 302 is significantly improved as compared to the metal bezel 300. Further, in a conventional wristwatch having an inner diameter of 30 to 32mm, if the bezel 300 is made of metal (e.g., stainless steel) having a thickness of 2.0mm or less, a sleeve for inserting a button pin is projected toward the inner periphery of the bezel 300, and thus the diameter of the bezel 300 needs to be increased accordingly. Conversely, if the thickness of the metal raceway 300 exceeds 3.0mm, there is a possibility that signal reception will be hindered.

In a preferred embodiment of the present invention, a colored film is applied to the inner surface of non-metallic back cover 306. According to this configuration, the rear cover can be given a pleasant feeling.

In a preferred embodiment of the invention, the material of the transparent window panel 304 is plastic or glass.

Drawings

FIG. 1 is a schematic diagram showing features of the present invention;

FIG. 2 is a cross-sectional view showing the structural features of the watch case of the metal radio wave wristwatch according to the present invention;

FIG. 3 is an elevational view showing structural features of a watch case of a metal radio wave wristwatch according to the present invention;

FIG. 4 is a plan view showing structural features of a watch case of a metal radio wave wristwatch according to the present invention;

FIG. 5 is a schematic view showing the configuration characteristics of a metallic radio wave wristwatch reception condition testing device according to the present invention; fig. 5(a) is a plan view of the inside of the shield case, and fig. 5(b) is a sectional view of the inside of the shield case.

FIG. 6 is a sectional view showing a structural feature of a watch case of a conventional metal wristwatch;

fig. 7 is a top view of the watch core with built-in antenna, seen from above (dial side);

fig. 8 is a view showing a state where a shield plate is attached to a watch core with a built-in antenna, as viewed from above (dial side);

FIG. 9 is a top view of the watch movement with the built-in antenna, seen from below (back cover side);

figure 10 is a side view of the watch core with a built-in antenna, seen from the side.

Detailed Description

A preferred embodiment of a radio wave wristwatch designed according to the present invention will now be described in detail with reference to the accompanying drawings.

FIG. 2 is a cross-sectional view showing the structural features of a radio wave wristwatch according to the present invention; FIG. 3 is a side view thereof; fig. 4 is a plan view thereof.

As shown in these figures, a radio wave wristwatch 1 designed according to the present invention employs a case composed of three elements in a lap joint manner: these three elements are, respectively, a metal bezel 2 for forming the outer shape of the watch case, an annular metal window frame 4 attached to the upper surface of the metal bezel 2 and constituting the edge of the transparent window plate 3, and a metal back cover bezel 6 attached to the back surface of the metal bezel 2 and constituting the edge of the non-metal back cover 5.

The purpose of using the metal bezel 2, which constitutes the case outline, is to maintain the watch case strength, and it also has the function of mounting the operating buttons 10, 10 inserted inside the bezel 2. A pair of watch holders 11, 11 integrated with the bezel are provided at appropriate positions on the outer ring of the metal bezel 2, and the watch holders 11, 11 are used for fixing a band. The metal seat 2 is preferably made of a non-magnetic or weakly magnetic metal material having a relatively high radio wave transmission capability. Such as SUS, Ti, Bs, Al, titanium alloy, aluminum alloy, etc., can be used as such metal materials. In the illustrated embodiment, SUS316L stainless steel material having a thickness of 3.0mm was used. Furthermore, the metal seat ring 2 has an annular shape with an inner diameter of about 32 mm. Further, when the height D2 of the watch case 9 is about 6mm, the height D1 of the bezel 2 is about 4 mm. That is, in determining their dimensional relationship, the height D1 of bezel 2 should be less than the height D2 of bezel 9 (i.e., D1 < D2). According to the intensive studies conducted by the inventors, good effects are obtained when the height D1 of the bezel 2 is determined to be 1 to 3mm (preferably 1.5 to 2.5mm), that is, less than the height D2 of the watch core 9, under the condition that the height D2 of the watch core 9 with a built-in antenna is 5 to 7 mm. The movement with the built-in antenna used in the illustrated embodiment has the same structural features as the movement of the built-in radio wave watches MJW-100, 200, 300 previously disclosed by Maruman limited.

This dimensional relationship can strongly reverse the traditional watch case theory; the reason for this is explained below. Those skilled in the art of watch making put forward the conventional theory of: the inherent function of the bezel 2 is to surround the entire outer ring of the watch movement 9 to protect the movement from shocks and the like, and therefore the height D1 of the bezel 2, i.e. the thickness of the watch case, must be so large as to completely surround the movement 9.

As the annular metal frame 4 for the transparent window panel 3, a non-magnetic or weakly magnetic metal material having a relatively high radio wave penetration ability is selected. Such as SUS, Ti, Bs, Al, titanium alloy, aluminum alloy, etc., can be used as such metal materials. In the illustrated embodiment, SUS316L stainless steel material having a thickness of about 2.0mm is used. The transparent window panel 3 may be made of glass or plastic material as desired by the designer.

The metallic back cover bezel 6 for forming the edge of the non-metallic back cover 5 is preferably made of a non-magnetic or weakly magnetic metallic material having a relatively high radio wave penetration ability. Such as SUS, Ti, Bs, Al, titanium alloy, aluminum alloy, etc., can be used as such metal materials. In the illustrated embodiment, SUS316L stainless steel material having a thickness of about 2.0mm is used. The non-metallic rear cover 5 may be made of glass or plastic material as desired by the designer. And a colored film with, for example, a metallic color or black color may be attached to the inner surface of the non-metallic back cover 5 to give a pleasant feeling.

In the watch case, a non-metallic dial 7 is arranged in a position opposite to the transparent window plate 3. A watch movement 9 with a built-in antenna, thereby having a radio wave watch function, is mounted in a space 8 formed between the non-metallic dial 7 and the non-metallic back cover 5.

The non-metallic dial 7 may be made of glass, plastic or the like as desired by the designer. In the illustrated embodiment, the watch core 9 with the built-in antenna is disc-shaped with a height D2 of about 6mm and an outer diameter of about 25 mm.

In particular, the watch movement has a case made of a relatively thin plastic material, in the shape of a circular plate. The left side (aporation) of the outer circle of the shell is cut flat, and a ferrite magnetic rod is installed in the shell; this is a rod-shaped long wave antenna. The ferrite bar antenna is installed in a vertical direction of a disk-shaped housing.

Fig. 7 to 10 show an example of a structure of a movement 9 with a built-in antenna used in a radio wave wristwatch designed according to the present invention. Fig. 7 and 8 are plan views of the watch core 9 with the built-in antenna as viewed from above (dial side). Fig. 9 is a top view of the watch core 9 with the built-in antenna seen from below (back cover side). Fig. 10 is a side view of the watch core 9 with the built-in antenna, seen from the side.

A ferrite bar 701 is installed near the tangential direction of the outer ring of the case 704 so that both ends thereof are fixed by the case 704. Here, three faces of the antenna 701, i.e., upper, lower, and side faces on the outer edge side are exposed to the outside of the case 704. Reference numeral 701a denotes a coil, and 701b denotes a ferrite rod constituting an antenna core. The lower face (back cover side) of a circular plate-shaped plastic watch case 704 is opened, and a motor coil 702, a gear mechanism 703, a battery 705, quartz oscillators 707a and 707b, a Printed Circuit Board (PCB)708 and the like are housed in the watch case 704. Among these elements, a battery 705 is fixed to a battery holder 706. On the upper face (dial side) of the case 704, a shield sheet 709 made of stainless steel for shielding high-frequency noise generated by the motor coil 702 is provided. Fig. 10 is a side view of the watch core 9 with the built-in antenna seen from the side (in the direction of 6 o' clock). As can be seen, the height D2 of the watch core 9 with the built-in antenna is approximately equal to the thickness D3 of the antenna 701.

Now returning to fig. 2. The annular metal window frame 4 is provided with an extension 4a extending downwards, i.e. in the direction of the metal seat ring 2, over the entire circumference of its lower surface. In the illustrated embodiment, the extension 4a extends for a length of about 1 mm. The thickness of the extension 4a is about 2 mm.

The metal back cover rim 6 has an extension 6a extending upward, i.e., in the direction of the metal seat 2, over the entire circumference of the upper surface thereof. In the illustrated embodiment, the extension 6a extends for a length of about 1 mm. The thickness of the extension 6a is about 2 mm.

On the other hand, height D1 of metal bezel 2 can be reduced by the sum of the extension lengths of extension 4a and extension 6a so that the overall height of the watch case remains constant, i.e. the same height value as a conventional watch case.

Therefore, inside the watch case, the outer edge of the watch movement 9 with built-in antenna, which is arranged between the non-metallic dial 7 and the non-metallic back cover 5, should be surrounded so that this area is divided into three areas in the vertical direction by the metal bezel 2, the lower extension 4a of the annular metal window frame 4 and the upper extension 6a of the metal back cover bezel 6.

Here, "enclosed so that the area is divided into three areas in the vertical direction" means that, although the entire outer edge of the watch core is uniformly enclosed in a conventional manner, there is no gap formed by the metal bezel 102 shown in fig. 6; however, in the present invention, as shown in fig. 2, the metal bezel 2 can be divided into a portion surrounded by the lower extension 4a of the annular metal window frame 4 and a portion surrounded by the upper extension 6a of the metal back cover bezel 6.

Specifically, the watch movement 9 has a wide middle region of the outer edge surrounded by the metal bezel 2, a narrow upper region of the outer edge surrounded by the lower extension 4a of the annular metal window frame 4, and a narrow lower region of the outer edge surrounded by the upper extension 6a of the metal back cover bezel 6.

Here, the required thicknesses of the metal bezel 2 forming the case outline, the lower extension 4a of the annular metal window frame 4 located above the metal bezel 2, and the upper extension 6a of the metal back cover bezel 6 located on the back of the metal bezel 2 can be compared. Since the metal bezel 2 must maintain the strength of the watch case, it is difficult to reduce its thickness. However, the thickness of the lower extension 4a of the annular metal window frame 4 and the upper extension 6a of the metal back cover bezel 6 can be significantly reduced because there is no such high strength requirement for the extensions 4a and 6 a. Thus, the thickness of the extensions 4a and 6a may be less than the thickness of the race 2. Thereby, the radio wave penetration ability of the entire outer edge portion of the space 8 accommodating the movement 9 can be improved to achieve a sufficiently high radio wave time signal reception sensitivity, thereby enabling the radio wave wristwatch to reach a level capable of normal operation.

Although in the above-described embodiment, the extending portions 4a and 6a extend in both the upper and lower directions from the annular metal window frame 4 and the metal back cover bezel 6, respectively, in the present invention, it is also possible to extend in one direction only from the annular metal window frame 4 or only from the metal back cover bezel 6.

Specifically, the following three embodiments of the outer edge extension can be designed according to the present invention, in accordance with the above-described configuration of the extension.

The first embodiment is a wristwatch case characterized in that only the annular metal window frame 4 extends downward to form a lower extension 4 a. If the height of the whole watch case remains the same, the height of the metal bezel 2 will decrease accordingly. In this case, the lower wider region of the outer band of the watch movement 9 will be surrounded by the metal bezel 2, while the upper narrower region will be surrounded by the lower extension 4a of the annular metal window frame 4 (see fig. 1 (b)).

A second embodiment is a watch case characterized in that only the metal back cover bezel 6 is extended upward to form an upper extension portion 6 a. If the height of the whole watch case remains the same, the height of the metal bezel 2 will decrease accordingly. In this case, the upper wider region of the outer band of the watch movement 9 will be surrounded by the metal bezel 2, while the lower narrower region will be surrounded by the upper extension 6a of the annular metal back cover bezel 6 (see fig. 1 (d)).

A third embodiment is a wristwatch case characterized in that not only the annular metal window frame 4 extends downward to form a lower extension 4a, but also the metal back cover bezel 6 extends upward to form an upper extension 6 a. If the height of the whole watch case remains the same, the height of the metal bezel 2 will decrease accordingly. In this case, the wider region of the outer band middle of the watch core 9 will be surrounded by the metal bezel 2, while the narrower region of the upper part will be surrounded by the lower extension 4a of the annular metal window frame, and the narrower region of the lower part will be surrounded by the upper extension 6a of the annular metal back cover bezel (see fig. 1 (c)).

Next, using an embodiment of the radio wave wristwatch designed according to the present invention, a comparative test was performed on the effect of use of the radio wave wristwatch designed according to the present invention, against some radio wave watches.

Radio wave wristwatch embodiments designed according to this invention

According to the sectional structure shown in fig. 2, a watch case (commonly referred to as a bezel in the industry) 2, a front cover (commonly referred to as a ring-shaped metal window frame in the industry) 4 and a back cover bezel 6 were made of SUS316L stainless steel. Height D1 of case 2 was set to 4mm, and height D2 of movement 9 was determined to be 6 mm. The rear cover 5 is made of a glass plate. The front cover 4 extends downward 1mm, forming a lower extension 4 a. The rear cover bezel 6 extends upward 1mm forming an upper extension 6 a. The thickness of the seat ring 2 is reduced to 3mm in view of keeping the strength constant. The dial 7 is made of a plastic plate or a glass plate. The transparent window plate 3 is made of a glass plate. The thickness of the lower extension 4a and the upper extension 6a is 2mm, respectively.

Comparative example 1

Comparative example 1 is a general metal watch case (not a radio wave watch). A watch core with a built-in antenna is mounted in the watch case. The dial 106 is made of glass. In the cross-sectional structure shown in fig. 6, the case 102, the front cover 104 and the back cover 105 were made of SUS304 stainless steel. A conventional watch case is used as the watch case 102. Thus, the height D1 of the watch case 102 is still greater than the height D2 of the watch movement 107 (D1 > D2). The dial 106 is made of a plastic plate or a glass plate, and the transparent window plate 103 is made of a glass plate.

Comparative example 2

Comparative example 2 is a general metal watch case. A watch core with a built-in antenna is mounted in the watch case. The dial 106 is made of a glass plate or a plastic plate. And the rear cover 105 is made of a glass plate. In the cross-sectional structure shown in fig. 6, the case 102, the front cover 104 and the back cover bezel (see reference numeral 6 in fig. 2) were made of SUS316L stainless steel. A conventional watch case is used as the watch case 102. Thus, the height D1 of the watch case 102 is still greater than the height D2 of the watch movement 107 (D1 > D2). The dial 106 is made of a plastic plate or a glass plate, and the transparent window plate 103 is made of a glass plate. The rear cover is made of a glass plate (see reference numeral 5 in fig. 2).

Test method

As shown in fig. 5, each of the wristwatch embodiment and comparative examples 1 and 2 designed according to the present invention was placed in a shield case (a container capable of shielding all extraneous radio waves), and a radio time signal magnetic field having a frequency of 60Hz was generated by a radio time signal generator 13. By detecting the magnetic field intensity value at the time when each of the look-up tables receives the radio wave time signal, the magnetic field intensity can be changed, and the reception performance of each watch can be tested. Fig. 5(a) is a plan view of the inside of the shield case, and fig. 5(b) is a sectional view of the inside of the shield case. Reference numeral 14 denotes an antenna, 15 denotes a stand for placing an object to be measured, and 16 denotes an object to be measured (a wristwatch to be measured).

Test results

Magnetic field intensity of measured object (dB mu V/m)

Example 42

Comparative example 163

Comparative example 250dB or more

Here, a lower magnetic field strength value indicates a higher reception performance (easy signal reception).

Conclusion

For the embodiment, a higher reception performance can be achieved in all areas within the set reception area. It is shown that the wristwatch of the embodiment can be used as a radio wave wristwatch, and can achieve a practical application level and obtain a satisfactory effect. Because the shell is made of metal materials, the shell gives people a comfortable feeling, can meet the taste of consumers, and has sufficient material sources. In addition, the manufacturing cost of the wristwatch according to the embodiment is lower than that of a wristwatch made of a material such as ceramic.

In comparative example 1 and comparative example 2, a high receiving capability could not be obtained. It was shown that comparative examples 1 and 2 could not be used as radio wave watches and could not reach practical application levels.

With the radio wave wristwatch described in the above embodiment, not only can the movement achieve higher signal reception performance; moreover, the outer edge of the watch except the back cover part is surrounded by the metal material, so that the appearance of the watch is extremely comfortable, and the watch back cover cannot be seen after the watch is worn. Moreover, the watch can be manufactured by using the traditional metal watch manufacturing technology at lower cost. Therefore, the present invention will play an important role in popularizing such a radio wave wristwatch.

As is apparent from the above description, according to the present invention, the radio wave penetration ability of the upper face, the lower face and the circumferential face of the core of the radio wave wristwatch is improved, while the strength and thickness of the metal bezel constituting the case body are maintained at desired levels. Therefore, the radio wave wristwatch can be made to have a metallic appearance similar to that of a general wristwatch.

Claims (8)

1. A radio wave watch, comprising:

watch case formed by three elements assembled together in a lap joint, said three elements being respectively: an annular metal seat ring is arranged on the inner side of the annular metal seat ring,

an annular metal window frame which is positioned on the metal seat ring and forms the outer edge of the transparent window plate,

and an annular metal back cover seat ring which is positioned on the back surface of the metal seat ring and forms the outer edge of the non-metal back cover;

a non-metallic dial mounted in said case and disposed to face the transparent window plate; and

a watch core with a built-in antenna, which is arranged between the non-metal dial and the non-metal back cover,

the method is characterized in that:

the dimensional relationship between the metal bezel and the watch core with the built-in antenna is determined such that the height of the metal bezel is smaller than the height of the watch core with the built-in antenna, and upper and lower outer edges of the watch core with the built-in antenna, which extend in a vertical direction from the metal bezel, are surrounded by the lower extension of the annular metal window frame and the upper extension of the metal back cover bezel.

2. The radio wave wristwatch of claim 1, wherein: the material of the metal seat ring is a non-magnetic metal or a weak magnetic metal.

3. The radio wave wristwatch of claim 1, wherein: the material of the annular metal window frame is non-magnetic metal or weak magnetic metal.

4. The radio wave wristwatch of claim 1, wherein: the material of the metal back cover seat ring is non-magnetic metal or weak magnetic metal.

5. The radio wave wristwatch of claim 1, wherein: the material of the non-metal dial is plastic or glass.

6. The radio wave wristwatch of claim 1, wherein: the non-metal rear cover is made of plastic or glass.

7. The radio wave wristwatch of claim 1, wherein: and a film with a metal color or a plurality of paint films are stuck on the inner surface of the non-metal rear cover.

8. The radio wave wristwatch of claim 1, wherein: the transparent window plate is made of plastic or glass.