CN1701464B

CN1701464B - Electronic device having metal package unit having built-in antenna unit

Info

Publication number: CN1701464B
Application number: CN2004800010436A
Authority: CN
Inventors: 池田家信; 伊原隆史; 小林稔; 前川泰雄
Original assignee: Citizen Watch Co Ltd
Current assignee: Citizen Watch Co Ltd
Priority date: 2003-05-15
Filing date: 2004-05-17
Publication date: 2011-01-19
Anticipated expiration: 2024-05-17
Also published as: CN1701464A; JP2004340700A

Abstract

An electronic device comprises at least an antenna, an information processing apparatus for the purpose of processing information captured by the antenna, and a metal exterior parts capable of housing therewithin the antenna and the information processing apparatus, wherein the metal exterior parts is configured so that the antenna can receive magnetic flux from outside the metal exterior parts that has passed through the metal exterior parts and can resonate, and wherein at least a part of the metal exterior parts has an electrical resistance value that is different from another part of the metal exterior parts.

Description

Electronic device having metal exterior member with built-in antenna unit

Technical Field

The present invention relates to an electronic device having the following functions: receiving a radio signal, transmitting prescribed information (including time information), and displaying or giving a notification about the displayed prescribed information, and correcting the time information to accurate time information. In particular, the present invention relates to an electronic device in which a metal exterior member, such as a metal case, is used and which has improved radio signal receiving performance.

Further, more particularly, the present invention relates to an electronic device configured such that its antenna performance for receiving a radio signal does not deteriorate even if a resonance antenna is in the vicinity of a metal object or placed in a metal exterior part, or more particularly, to a radio-controlled timepiece in which an antenna is disposed in a metal exterior part.

Background

In recent years, many electronic devices such as watches, mobile phones, radio communication apparatuses, etc., which receive a long-wave standard radio signal containing a time code therein, have appeared on the market, and have a radio signal correction function of automatically adjusting the time of a time holding circuit in the electronic device to a time of standard time during operation.

In the past, it has been known that the formats for displaying time in watches (a watch is a special case of such electronic devices) include analog, digital and combination. In the simulation mode, time is represented by two or three hands; in digital fashion, time is represented using electro-optical devices, such as LCDs or LEDs; the combination method is a combination of the above two methods.

As for these methods, in the analog timepiece, it is also known that a user can select the timepiece according to the user's preference, such as whether the timepiece has a second hand or a calendar, and also whether the timepiece has such a second time keeping function as a time recording function, an alarm function, a lunar calendar indication function, and the like.

Further, although the accuracy of the electronic timepiece in the past is generally determined by the accuracy of a circuit block (such as a quartz oscillator) in the movement, with the establishment of transmission equipment for standard time radio signals in countries in recent years, a radio-controlled timepiece capable of performing automatic time correction by receiving these standard time signals has come into use.

As for these radio-controlled timepieces, there have been many patent applications (such as examined japanese patent publication No. 11-304973 and unexamined japanese patent publication No. 2001-33571).

In general, a radio-controlled timepiece automatically corrects a time error held by an internal counter in the timepiece itself by receiving a standard time radio signal, and it is possible to realize an indication error of a hand to be extremely close to 0 as long as the timepiece is in an environment capable of receiving a radio signal. The frequency of the standard time radio signal and the format of the data are established by the transmitting facility, and currently, there are transmissions other than japan, such as germany and the united states, for which radio-controlled timepieces are widely used. The radio signal used in the current radio-controlled timepiece is a long-wave signal because it can cover a wide area with a small transmission facility. Furthermore, in japan, to avoid interference on the boundary between radio signals at standard time, two transmitting stations in japan currently transmit different frequencies: 40 khz and 60 khz.

The following describes problems encountered in the past, and for example, a timepiece having a radio signal correction function (hereinafter referred to as a radio-controlled timepiece) is taken as a typical electronic device.

Specifically, a known radio-controlled timepiece receives a standard radio signal, which is a standard radio signal (carrier wave) containing time information, as described above, and extracts the time information from the radio signal, whereby accurate time can be obtained. The frequency of the radio signal containing time information is different for different countries, and for example, as in the above-mentioned japan, standard radio signals of 40 khz and 60 khz are transmitted under the control of the "general office" and the "postal department".

Fig. 20 is a general functional block diagram showing a specific example of such a radio-controlled timepiece. Such a radio-controlled timepiece is formed of an antenna 1, a radio-controlled timepiece 2, a CPU3, a display driving section 4, and an input device 5 and the like.

Further, although not shown in the drawings, the timepiece further includes hour, minute and second hands, or a display portion using a liquid-gas shield or the like.

In such a radio-controlled timepiece, first, a radio signal containing time information is received through the antenna 1.

The receiver 2 of the radio-controlled timepiece amplifies and detects the radio signal received by the antenna 1, and extracts and outputs time information from the radio signal. The CPU3 outputs current time data based on the time information output from the receiver 2 of the radio-controlled timepiece. The display driving section 4 causes the display section to display the current time based on the current time data output from the CPU 3. The input device 5 is used, for example, to input operation information such as reset or the like to the CPU 3.

The time information (time code) contained in the radio signal is a pulse signal having a period of 60 seconds, and although this pulse signal is different for different countries (such as japan), a pulse having a pulse width of any one of 200, 500, and 800 milliseconds per second is always superimposed on this pulse signal. The combination of these pulses can achieve a time of 60 seconds. The CPU3 can obtain time information (current time) by reading out the pulse width of this pulse every 1 second from the received pulse signal. The CPU generates the time displayed on the display section via the display driving section 4 using the obtained time information. Therefore, the radio-controlled timepiece can correct the displayed time for each prescribed time interval based on the received time information, thereby enabling the time to be displayed accurately at all times.

There is a wristwatch in which an antenna, a radio-controlled timepiece, a CPU, a display driving portion, and a display portion are mounted in a case enclosing the antenna. In order to enable the antenna to receive radio signals, the material used for the housing is usually a non-conductive material, such as synthetic resin or ceramic. That is, if the antenna is mounted in a case made of a conductive material such as metal, magnetic flux generated in the vicinity of the antenna is absorbed by the conductive material, hindering the generation of a resonance phenomenon, resulting in a significant deterioration in the receiving performance of the antenna.

Fig. 35 shows an overall structure of another specific example of the analog type radio controlled timepiece.

Specifically, in fig. 35, reference numeral 101 denotes an antenna that receives a radio signal, reference numeral 102 is a watch movement that drives hands, reference numeral 103 is a case that houses the watch movement 102 and the antenna 101, reference numeral 104 is a back cover, reference numeral 105 is a dial having time scales, and reference numeral 106 is glass.

In fig. 35, an antenna 101 is formed of an antenna core 101a (e.g., a ferrite or amorphous alloy) having a high magnetic permeability and a coil portion 101b wound around the antenna core 101a, and the antenna 101 is placed together with a watch movement 102 in a closed space 107 formed by a case 103, a rear cover 104 and a dial 105.

In this timepiece, when a radio signal 109 passing through the case 103 reaches and passes through the antenna core 101a, a current is generated in the coil portion 101 b. A circuit module (not shown) forming part of the watch movement 102 is electrically coupled across the coil portion 101b of the antenna, and the current generated by the coil portion 101b of the antenna is sent to a circuit via this coupling. The current sent to the circuit generates a resonance at the same frequency as that predetermined by the standard time radio signal and filtered by the quartz resonator, from which only the time information is extracted by a decoding circuit (not shown).

In this case, the watch movement 102 has a counter in its circuitry for time keeping, this time being separate from the time information mentioned above. The watch movement 102 compares the time corresponding to the time keeping counter with the filtered time information and, in the case of a difference therebetween, outputs a hand correction command to a motor module (not shown) to rotate a motor to correct the hands to the time information from the standard time radio signal. By such an action procedure, the time displayed by the timepiece is corrected to the correct time at the time point when the standard time radio signal is received.

However, the antenna 101 and the watch movement 102 in fig. 35 are both accommodated in an enclosed space 107 enclosed by the case 103, the back cover 104, and the dial 105, and the antenna 101 can receive only an extraneous radio signal 109 in this enclosed space 107.

For this reason, in fig. 35, the substance forming the housing 103 and the back cover 104 has a high eddy current loss, and this material is typically a high polymer resin. In this way, the radio signal 109 can reach the antenna 101 housed in the enclosed space 107 without being attenuated by the housing 103 and the rear cover 104.

However, in the case where the case 103 is formed of a high polymer resin, there is a significant loss in hardness as compared with metals such as stainless steel or titanium used in ordinary watches. For this reason, in order to prevent the breakage caused by the fall of the wristwatch in normal use, it is necessary to make the material thickness of the case 103 and the back cover 104 larger than the thickness of the case and the back cover formed of metal, which causes a problem that the wristwatch itself becomes large.

Fig. 36 shows a previous example of an improvement to the above-described situation. Fig. 36 shows a plan view of a previous modified example, in which the same reference numerals are assigned with respect to the same components as those in fig. 35, and their description will not be repeated here. As shown in fig. 36, this is a commercially produced structure in which the housing 103 and the back cover 104 are formed of metal and the antenna case 110 is made of high polymer resin, and the structure is fixed to a part thereof which is not stacked in a planar relationship with the metal housing 103 and the back cover 104, thereby coupling the sealed antenna 101 to the watch movement 102. With this product, since the antenna 101 is disposed outside the closed space 107, the closed space 107 being formed by the case 103, the back cover 104 and the dial 105, the radio signal incident to the antenna 101 tends to be unaffected by metal parts such as the case 103, and thus the radio signal 109 is likely to be received.

However, in this case, the shape of the final timepiece is very peculiar, and there is a problem that the design of the final timepiece is severely restricted.

In addition, since the case 103 and the antenna case 110 are made of high polymer resin and the antenna is also sealed inside the case 103 and the antenna case 110, the texture of the case 103 and the antenna case 110 is large and it is difficult to adapt to the design, and thus there is a problem in that its design is inevitably a design which is difficult for a user to receive.

Further, in the case where the case 103 and the rear cover 104 are made of a high polymer resin, it is disadvantageous in that texture is deteriorated compared to metal. Although it is possible to achieve metallic gloss by surface treatment of a high polymer resin, there is still an undeniable disadvantage in terms of gloss and texture in comparison with metals.

Although there is a particularly useful product corresponding to the above, in which, as shown in fig. 35, only a part of the dial face 105 which is directly visible to the user, i.e., the front bezel 111 is made of metal, and the case 103 and the back cover 104 of the side thereof are formed of high polymer resin, the total thickness of the final timepiece is increased and texture is deteriorated as compared with a universal timepiece having a metal exterior part. With a high polymer resin, there is a possibility that plastic deformation tends to occur, for example, due to fastening of the back cover 104, and therefore, there is a problem that the water seal of the joint portion between the back cover 104 and the case 103, and further, there is a problem that it is impossible to include in a timepiece production group of a diver's watch having high waterproof performance.

Although there is a practical product in which the housing and the rear cover are formed of a material other than a high polymer resin, such as a ceramic-type non-metallic material, which requires sintering to maintain the rigidity of the ceramic, corresponding to the above, there is a problem in that accurate processing cannot be achieved after sintering or polishing into a complicated shape cannot be performed. Therefore, there is a serious limitation on the design of the external component. Further, due to the brittleness of ceramics, there is a problem that chipping and cracking are caused by impact.

In order to avoid such problems concerning antenna reception, the use of a case made of synthetic resin leads not only to the impairment resistance and the chemical resistance being impaired, but also to the attractive appearance and strong texture required for accessories of the timepiece being impaired. For this reason, a radio controlled timepiece having a metal case is proposed.

Fig. 21 is a sectional view showing an example of a structure of a radio-controlled timepiece in which a part of a case is made of metal. The case 10 of this watch generally comprises: a main body 11, a rear cover 12 and a wind shield 13. The watch movement 14 is arranged in a body which is connected to the watch band by means of well-known devices. The dial 15 and hands 16 are also arranged above the watch movement 14 by well-known means. The strip antenna 17 is a long-wavelength magnetic antenna, and the strip antenna 17 is provided below the watch movement 14 so as to be positioned above the back cover 12. The strip antenna 17 is formed by a magnetic core member 18 and a coil 20 surrounding the magnetic core member 18, and is fixed to an upper surface of a holding member made of synthetic resin.

The watch movement 14 has: as with the radio-controlled watch receiver, CPU and display driver section described above, the watch movement 14 is electrically coupled to the bar antenna 17 through the conductor 21. Therefore, according to the standard radio signal received by the bar antenna 17, the CPU of the watch movement 14 moves a gear mechanism (not shown) in the display driving section to drive the positions of the hands 16 of the display section, thereby constantly correcting these hands. In this specification, the vertical direction represents the vertical direction in fig. 21.

The body 11 is made of a non-hollow, i.e. solid, electrically conductive material, such as solid stainless steel. The windshield 13 is made of glass, which is a nonconductive material, and the windshield 13 is fixed to the outermost portion of the body 11 by a known means such as an adhesive or the like. The dial 15 is made of synthetic resin or ceramic which is a non-conductive material. The case back cover 12 is formed by a ring-shaped peripheral frame 22, which is made of stainless steel and is fixed to the main body 11, and a glass 23 is fixed to the inside of the peripheral frame 22. In this way, although the non-conductive material can be seen on the upper and lower surfaces of the main body of this wristwatch, since the side portions of the case are made of metal, there is an advantage in that the attractive appearance and strong texture of the timepiece accessory are not sacrificed (refer to, for example, unexamined japanese patent publication No. 2001-33571).

Specifically, as adopted in japanese unexamined patent publication No.2001-33571, in the case of forming the back cover from a non-conductive material (such as a high polymer resin, glass or ceramic in general), although having the advantages described above, there are many restrictions in selecting materials, difficulties in manufacturing, and problems in achieving a pleasant appearance of the final timepiece, and it is therefore desirable to form the case back cover made of metal.

For these reasons, there have been great restrictions on the materials of the external parts when developing radio-controlled timepieces in the past, that is, it is extremely difficult to miniaturize the final timepiece.

In the radio-controlled timepiece, it can be considered that the reception performance can be determined by the antenna characteristic and the reception circuit characteristic.

This means that, according to the general technical knowledge in the past, the lower limit of the input signal of the receiving circuit or the receiving integrated circuit is actually about 1 microvolt signal amplitude, and in order to obtain the actual receiving performance, it is necessary to obtain an output signal having an amplitude of about 1 microvolt and an electric field strength (radio signal strength) of the signal receiving antenna of 40 to 50 db · microvolt/m.

For this reason, for the case where there is a size limitation, a resonance type antenna capable of achieving a large signal output is generally used.

Since a radio signal is long-wavelength, a strip antenna in which a wire is wound around a core is generally used as this type of antenna.

In this type of receiving antenna, since the output of the receiving antenna is substantially proportional to the size of the receiving antenna, the antenna cannot be excessively small in order to obtain a practically usable receiving performance, which causes problems in the receiving performance and the receiving position of a small timepiece such as a wristwatch.

Further, when the receiving antenna is accommodated in the metal exterior part, the output of the receiving antenna drops sharply.

For this reason, in order to utilize a radio signal, a wristwatch must have a component structure or design completely different from that of a past timepiece, and further, must consider that a reception performance cannot be hindered.

Important items for a wristwatch are light weight, thinness, portability, high degree of freedom in design, good texture (high-quality feeling), and a built-in antenna unit and a metallic exterior member are desired.

As described above, in the past radio-controlled timepiece, the main method is to install an antenna in an external closed space or to incorporate the antenna.

In the case where the material of the rear cover and the side wall is metal, the receiving antenna is generally mounted on the outside.

In this case, since the antenna case of the receiving antenna is made of a non-metal such as plastic so as not to deteriorate the receiving performance, the antenna case is in the form of a large ridge, resulting in a great deterioration in compactness, thinness and portability, and freedom of design.

In the case where the receiving antenna is built-in, although ceramics or plastics are used as materials of exterior parts (back cover and side wall) of the timepiece so as not to degrade the receiving performance, the strength of these materials is low, the thickness of the timepiece is increased, and thus, the storability and the portability are sacrificed, and a great restriction is imposed on the design.

In addition, the result obtained is a watch with little texture of the external texture.

For this reason, as seen in japanese unexamined patent publication No.2-126408, for example, there is a case where a metal antenna is provided in the strap of the wristwatch.

Further, a timepiece as disclosed in japanese unexamined patent publication No.5-81787, in which an antenna is provided between a dial and a wind shield, and a coil of this antenna is wound around a magnetic core, not only eliminates the antenna from a disturbing radio signal metal case, but also provides a unique design. In addition, in international patent application WO 95/27928, a watch is disclosed, in the construction of which an antenna is mounted on the side of the watch case.

Further, a timepiece such as disclosed in european patent publication 0382130, in which an antenna is provided on an upper surface such as a case in a ring shape.

However, in the conventional structure in which the antenna is provided in the band, since the antenna is provided in the band, it is necessary to electrically connect the antenna to the electronic device itself, and it is impossible to impart sufficient flexibility to the joint portion between the antenna and the electronic device.

Furthermore, since it is impossible to use a metal strap that interferes with radio signals, it is necessary to use a special strap, which imposes restrictions on materials and design.

Further, in the timepiece in which the antenna is provided on the upper surface of the timepiece or on the side surface of the timepiece, since the antenna is separated from the metal part of the timepiece itself, there is a problem that the thickness or the size of the whole timepiece is increased, which imposes a limitation on the design.

Further, european patent publication 0382130 discloses a timepiece in which an antenna is provided on an upper surface of a case in a ring shape. A problem with such a timepiece is that if there is metal in the annular portion, it is essentially necessary to provide an antenna separate from the timepiece since reception is not possible.

Further, although japanese unexamined patent publication No.11-064547 discloses a timepiece in which a coil is provided in a concave portion in a peripheral portion of a circuit board, and a magnetic core is provided in a curved portion in a circumferential direction of the printed circuit board. However, this will cause the following problems: not only is the manufacturing process complicated, but also assembly is difficult during the manufacturing process.

In the publications such as Japanese unexamined patent publication No.2001-33571 or Japanese unexamined patent publication No.2001-30524, a structure of a timepiece is shown. In which the wind shield and the back cover part of the timepiece are made of a non-metallic material such as glass or ceramic, and the middle part of the timepiece is made of a metallic material, like in the past watches, so that a sufficient number of radio signals can reach the antenna.

Japanese unexamined patent publication No.2001-208875 discloses a technique relating to an identification mark of a timepiece. The basic technical composition of the disclosed identification system is as follows: when boarding a ski lift or the like, an identification mark is provided in a wristwatch held by the user, and information in the identification mark is exchanged with an identification device provided on the elevator door, whereby it is possible to determine whether the user is an authorized passenger.

In this patent publication, however, the basic idea is that a strong high-frequency radio signal is emitted from the identification means, the watch with the identification mark is brought into its vicinity, and the integrated circuit in the watch is excited, and the information of said identification mark is read by the identification means.

That is to say, in the above-mentioned publication, the configuration of the watch is such that, when a high-frequency radio signal is received by an antenna provided in the timepiece, then resonance occurs in an integrated circuit in the timepiece, resulting in the following: the integrated circuit receives the electromotive force, energizes the integrated circuit, and reads out identification mark information in the timepiece while giving a radio notice to the identification device.

Thus, this patent publication, while giving the following teaching: the information can be converted by the operation of the antenna, which is also present in a watch having a metallic external part. However, with respect to the present application, the obvious differences in technical ideas are: an identification device for transmitting a high-frequency radio signal is provided, which requires a timepiece having an identification mark to be brought close to the identification device, an antenna provided in the timepiece being based on a strip antenna so that the high-frequency radio signal transmitted by the identification device can be sufficiently received. Moreover, since it is necessary to make this reception as thin and large as possible in the watch, it is necessary to use a square antenna of the thin and straight type, which is clearly different from the present application. In addition, a specific relationship is established between the antenna element and the metallic exterior element.

Further, in japanese unexamined utility model publication No.57-131042, there is a proposal relating to a wristwatch in which an antenna is provided that uses a circular magnetic strip that is a C-shaped ferromagnetic body surrounding a conductor member. However, this known example relates to an antenna for a wristwatch having a radio device, which antenna is arranged only on the outside of the wristwatch, obviously without an antenna being arranged in the metal outer part.

Further, although japanese unexamined patent publication No.6-215942 says that the effect of the inductor core as a discrete component is a chip inductor, it is obvious not only from the aspect of the technical field but also from the aspect of the object and technical constitution of the invention, as well as from the aspect of the antenna of the wristwatch of the present invention.

In japanese unexamined patent publication No.11-74138, although a transformer is referred to in which a dust core is a combination of a U-shaped member and an I-shaped member; the secondary winding is wound around said U-shaped element, which involves the process of obtaining a high voltage transformer, which differs not only significantly from the antenna of the watch of the invention in terms of technical field, but also substantially in terms of the purpose and technical constitution of the invention.

In the same manner, japanese unexamined utility model publication No.61-203516 discloses a structure in which the abutting surface of the core is inclined with respect to the vertical magnetic path direction, which involves the process of obtaining an inductance element, which is not only significantly different from the antenna of the wristwatch of the present invention in the technical field, but also substantially different in the object and technical constitution of the invention.

A proposal is found in japanese unexamined patent publication No.2002-184637 that this known example, relating to a high-voltage transformer, not only differs significantly in the technical field from the antenna of the wristwatch of the present invention, but also differs substantially in the object and technical constitution, with respect to tapering the gap of the coil core and changing the surface area.

Furthermore, although the above known references make reference to a structure in which the core of the inductor is made as a single element, this is in relation to high-voltage transformers or chip inductors, and is not only significantly different from the antenna of the watch of the invention in terms of technical field, but also substantially different in terms of object and technical constitution.

That is, the above-mentioned conventional examples are for the reason that the output of the antenna is drastically reduced by placing the antenna in the metal exterior part, and therefore, they aim to alleviate the drastic reduction of the output by making the material of the rear cover a non-metal material and to use a metal side having a high texture.

However, in the above conventional examples, since glass or ceramic is used, there is a problem that the thickness of the watch is increased.

Thus, in the past, since a large-sized high-sensitivity antenna structure had to be used for the radio-controlled timepiece, or since it was only possible to use the radio-controlled timepiece in an area where the radio signal field strength was large, so that its convenience was lost, it was inevitable to increase the manufacturing cost of the antenna structure including the design cost of the actual antenna.

Further, in the wristwatch of such a structure, if it is possible to make the radio signal reach the antenna and the rear cover is plated with a thin metal plating to give the user an impression of the metal material used, but in this way, the weight of the watch and the texture of the appearance lose significance, there is a problem that the image of the high-quality timepiece is lost.

Further, since the antenna is provided in the metal side wall, the output of the antenna is reduced and the reception performance is deteriorated.

For this reason, it has been difficult to realize a radio-controlled timepiece having all metal exterior parts and having a strong tactile sensation in the past.

In order to solve these problems in the prior art, the present inventors have found out the problems in Japanese patent application No. 2001-297095: when the antenna is provided in an enclosed space of a timepiece having a metal side wall or a metal back cover, the Q value is lowered, resulting in a reduction in the output of the antenna structure and a significant deterioration in the receiving performance. In order to solve this problem, a technical structure is proposed in which an antenna is made to have a special structure so that the reduction of the Q value of the antenna structure is made as small as possible, whereby the degradation of the reception performance of the antenna can be prevented.

However, in the method of making the antenna have a special structure, we have known that there is a limit to improvement in the receiving performance of the antenna structure, and as a result of further effective investigation, we have also known that the above-mentioned problems can be further improved by specifying the structure or characteristics of the metal exterior member including the terminal of the antenna structure.

Furthermore, as a result of effective investigation, it has been confirmed that: as for the conventional idea, in the case of bringing a metal object having conductivity into proximity or contact with an antenna element for receiving a radio signal, the radio signal is absorbed by the metal object, the radio signal does not reach the antenna element, and therefore the resonance output of the antenna element is reduced, and for example, the Q value is lowered, and in fact, the understanding of this problem in the past is wrong. And also confirmed that: even in the case where a metal object having conductivity is in proximity to or in contact with the antenna part, the radio signal has actually reached the antenna part, and in the case of non-resonance, the radio signal has reached the antenna substantially without hindrance since the magnetic flux flow generated by the external radio wave is trying to enter the timepiece, of course with some attenuation (e.g. about 3 db) therein.

Obviously, the problems that arise when an antenna resonates are: magnetic lines of force (magnetic flux) emitted from the magnetic core of the antenna element are drawn into the metal object, where the magnetic lines of force cause eddy currents, which attenuate the magnetic energy, thereby causing a problem of a decrease in the output of the antenna element, and also preventing normal reception.

That is, in the conventional radio-controlled timepiece as shown in fig. 21, there is no problem in terms of large radio signal receiving performance when used in a portable manner. However, since the glass 23 is fixed to the peripheral frame 22 of the back cover 12, there arises a problem that the glass 23 is broken in case of an impact such as dropping of the wristwatch. Furthermore, since the back cover 12 is in close contact with the wrist, sweat and the like may cause the glass 23 to fall from the peripheral frame 22 in long-term use, and therefore there is a significant risk that sweat, moisture, dust, and the like may intrude into the movement of the wristwatch (the antenna 1, the radio-controlled wristwatch receiver 2, the CPU3, the display drive section 4, and the like), thereby causing a significant reduction in the function of the wristwatch.

Further, since the rear cover 12 is provided with the glass 23, there is a problem that the number of steps of assembly is increased and the cost is increased in addition to the increase in the number of parts. Since the exterior member uses a non-metallic material, the wristwatch lacks a weight feeling, and there is a problem in a high-quality feeling and an eye-catching feeling.

The present invention has been made in view of the above-mentioned problems of the prior art. The present invention aims to provide an electronic device which can receive prescribed information such as time information even with a conventional metal case, and which does not present any problem when used in a portable manner. And this kind of electronic device still has waterproof quality, not only can improve the appearance quality, can also expand the change of design, the mode of expansion is the same with general type timepiece.

Further, as an object of the present invention, it is to provide an electronic device which can solve the above-mentioned problems in the past, has excellent radio signal receiving performance, and has a metal exterior part. In which an antenna component is provided which does not face restrictions in terms of material nor in terms of design.

In addition to the above object, in applying the present invention to a radio-controlled timepiece which is just a specific example of applying the present invention to an electronic device. Another object of the present invention is to provide a radio-controlled timepiece which can not only avoid an increase in volume of the wristwatch due to an increase in thickness but also provide a good feeling when worn on the wrist.

Further, the present invention provides a radio-controlled timepiece which can maintain the same receiving performance as that of a case and a back cover made of a high polymer or ceramics, and is compact and thinned, although it employs a metal exterior member and a metal back cover made of titanium or stainless steel and having a high magnetic permeability, similarly to the conventional timepiece.

Disclosure of Invention

To achieve the above object, the present invention adopts the following basic technical structure. Specifically, according to a first aspect of the present invention, an electronic apparatus has: at least one antenna, an information processing device for processing information captured by the antenna, and a metal exterior member for accommodating the antenna and the information processing device therein. The metal shell is configured to receive magnetic flux from outside the metal shell and through the metal shell and to resonate. And the resistance value of at least one part of the metal surface component is different from the resistance value of another part of the metal surface component.

According to a second aspect of the present invention, an electronic device has: at least one antenna, an information processing device for processing information captured by the antenna, and a metal exterior member for accommodating the antenna and the information processing device therein. The metal exterior member is constructed so that the antenna can receive magnetic flux which passes through the metal exterior member from the outside thereof and can resonate, and is formed of a main body (side wall) member and a back cover member. And, the main body (side wall) member and the back cover member are joined to each other, and the mutual peel strength range between the main body (side wall) member and the back cover member is: 10^-4N · m to 6.0N · m.

According to a third aspect of the present invention, an electronic apparatus has: at least one antenna, an information processing device for processing information captured by the antenna, and a metal exterior member for accommodating the antenna and the information processing device therein. The metal exterior member is structured such that the antenna can receive magnetic flux which comes from the outside of the metal exterior member, passes through the metal exterior member, and can resonate, and is formed of a main body (side wall) member and a back cover member. And, the body (side wall) member and the back cover member are engaged with each other via a screw mechanism, and a torque range in which the body (side wall) member and the back cover member are disengaged from each other is: 0.1N.m to 6.0 N.m, preferably 0.2 N.m to 3.5 N.m.

According to a fourth aspect of the present invention, there is provided an electronic apparatus having the above-described configuration, wherein an insertion member having a resistance value different from that of a metal forming the exterior metal member is provided in at least a part of a plurality of members joined to each other constituting the exterior metal member. According to a fifth aspect of the present invention, an electronic device having the above-described configuration, wherein a part of the joining surface of one of at least two metal members constituting the joining member is removed, and a gap is formed between the two joining members.

According to a sixth aspect of the present invention, a radio controlled timepiece has a case and a back cover each made of a metal material. The antenna is enclosed by the outer box, the back cover and the dial, the antenna is arranged to be overlapped with the dial in a plane, and the dial is usually made of non-metal materials.

Drawings

FIG. 1 is a view showing a structure of a specific example of an electronic apparatus according to the present invention;

FIG. 2 is a cross-sectional view of another embodiment of an electronic device according to the present invention;

FIG. 3 is a partial cross-sectional view of a specific example of an electronic device according to the present invention;

FIG. 4(A) is a schematic view showing an example of the shape of the joining surface between the body member and the back cover member, and FIG. 4(B) is a partial sectional view of FIG. 4 (A);

fig. 5(a) is a partial cross-sectional view showing a different specific example of the metallic exterior member of the present invention, and fig. 5(B) is a graph showing a relationship between a central angle of a sector and an antenna gain;

FIG. 6(A) is a partial cross-sectional view showing a different specific example of the metallic exterior member of the present invention, and FIG. 6(B) is a drawing for describing a sector;

FIG. 7(A) is a partial cross-sectional view showing another metal skin component of the present invention, and FIG. 7(B) is a drawing illustrating a sector;

FIG. 8(A) is a plan view showing a specific example of the case where a part of the engaging part in the sector of the metal exterior part of the present invention is left, and FIG. 8(B) is a drawing showing experimental data describing the effect of the structure of FIG. 8 (A);

FIG. 9 is a structural view showing a specific example of the antenna structure of the present invention;

fig. 10 is a graph showing a relationship between an inductance value and a gain in the antenna structure;

fig. 11 is a graph showing the relationship between the number of turns (T) and the gain of the antenna structure;

fig. 12(a) is a graph showing a relationship between a coil resistance value (Ω) and a gain of the antenna structure, and fig. 12(B) is a view showing an example of the coil structure;

fig. 13 is a graph showing a relationship between a coil resistance value (Ω) and a gain of the antenna structure:

FIG. 14 is a view showing an example of a component positioning structure in a radio-controlled wristwatch which is a specific example of the electronic device of the present invention;

fig. 15(a) and 15(B) are a plan view and a sectional view describing a positional relationship between the metal exterior part and the antenna;

FIG. 16 is a graph showing the relationship between the thickness of the main body part and the gain of the antenna in the electronic device of the present invention;

FIG. 17 is a graph showing the relationship between the gain of an antenna and the distance between a main body section and the antenna in the present invention;

FIG. 18 is a graph showing the relationship between the thickness of the back cover member and the gain of the antenna in the present invention;

FIG. 19 is a graph showing the gain of the antenna in relation to the distance between the antenna and the back cover member in the present invention;

FIG. 20 is a view showing a general structure of a radio controlled timepiece as a specific example of an electronic device of the invention;

fig. 21 is a view for describing details of a structure of a conventional radio-controlled timepiece;

fig. 22 is a view for describing the details of a radio-controlled timepiece structure as an example of an electronic device of the invention;

fig. 23 is a graph showing the relationship between torque and antenna gain;

FIG. 24 is a data diagram showing changes in the characteristic values of an antenna in an electronic device of the present invention due to the presence or absence of a contact point between a Vdd contact spring and a back cover member;

fig. 25 is a data diagram showing a change in the characteristic value of the antenna in the electronic device according to the present invention, which is caused by the presence or absence of the contact point between the movement and the back cover member;

fig. 26(a) is a partial sectional view showing a specific example structure in which an insulator is inserted between a main body member and a back cover member in an electronic device according to the present invention, and fig. 26(B) is a data diagram showing a change in characteristic value of an antenna caused by the insertion or non-insertion of the insulator;

fig. 27 is a graph showing the relationship between torque and antenna gain;

figure 28 is a plan view showing the positional relationship between the sectors and the antennas in the electronic device of the present invention;

FIG. 29 is a data diagram illustrating changes in antenna characteristic values for various specific examples of the electronic device of the present invention;

FIG. 30 is a data diagram illustrating changes in antenna characteristic values in another particular example of the electronic device of the invention;

fig. 31 is a drawing for describing the experimental results in which the antenna position effect is obtained in the case where a gap is provided in the joint part between the main body part and the back cover part constituting the metal exterior part;

fig. 32 is a view for describing the relationship among the antenna position, the gap length, and the central angle of the sector in the case where a gap is provided in the joint part between the main body part and the back cover part which constitute the metal exterior part;

FIG. 33 is a drawing illustrating an example of a structure for eliminating the influence of Vdd contact points in a metal exterior part;

FIG. 34 is a drawing illustrating an example of a structure for eliminating the influence of movement in a metal exterior part;

FIG. 35 is a sectional view showing a general structure of another specific example of the conventional radio-controlled timepiece;

FIG. 36 is a sectional view showing a general structure of another specific example of the conventional radio-controlled timepiece;

FIG. 37 is a cross-sectional view showing the general structure of another specific example of the radio-controlled timepiece of the invention;

FIG. 38 is a plan view showing a general structure of still another specific example of the radio-controlled timepiece of the invention;

fig. 39 is a view describing another example of the joint structure between the back cover member and the body member;

fig. 40 is a view describing another different example of the joint structure between the back cover member and the body member;

fig. 41 is a view describing still another example of the joint structure between the back cover member and the body member.

Detailed Description

The electronic device of the present invention can provide good receiving performance by adopting the above structure and using the antenna part having a simple structure without making a large change in the structure, material or design of the existing timepiece, mobile phone and radio communication apparatus, and can obtain a degree of freedom of design without a difference in the size or thickness of the electronic device itself from the prior art, and can easily realize an electronic device using the external part having good texture.

The structure of an example of an antenna structure of the invention and a radio-controlled timepiece using the antenna structure will be described in detail with reference to the drawings.

Specifically, fig. 1 is a cross-sectional view showing a general structure of a specific example of an electronic device according to the present invention. The figure shows an electronic device 30 having: an antenna 32, an information processing apparatus 33 for processing information captured by the antenna 32, and a metal exterior part 31 in which the antenna 32 and the information processing apparatus 33 are accommodated. The metal shell 31 is configured so that the antenna 32 receives magnetic flux from outside the metal shell 31 and through the metal shell and is resonant. In addition, the resistance value of at least a part of the metal exterior member 31 is different from the resistance value of another part of the metal exterior member 31.

Preferably, the electronic apparatus 30 is selected from a group of electronic apparatuses 30 including, for example, a timepiece, a mobile phone, and a wireless communication device.

Reference numeral 34 in fig. 1 denotes a computing device for driving the functions of the control electronics 30, such as a computer; reference numeral 35 is an information display/notification device such as a liquid-gas barrier display device or a speaker, etc., which can give a notification or produce a display of the prescribed information which has been calculated and processed.

Further, according to the present invention, it is preferable that the metallic exterior member 31 is made of one or more materials selected from the group consisting of: stainless steel, titanium alloy, gold alloy, silver alloy, copper alloy, brass, aluminum alloy, zinc alloy, manganese alloy, and super hard alloy (an alloy containing tungsten carbide and titanium carbide), and the structure must be capable of suppressing generation of eddy current when the antenna 32 resonates.

That is, because it is known that the reason why the receiving performance of the antenna 32 provided in the metal exterior part 31 is degraded according to the prior art is that: when the antenna resonates, electric lines of force (magnetic flux) from the antenna core are drawn into the metal object, generating eddy currents in the metal object, thereby causing magnetic energy to be attenuated, resulting in a decrease in the antenna output to cause abnormal reception. In the structure incorporating the basic idea of the present invention, it is necessary to introduce a structure into the metal exterior part 31 of the electronic device 30 such that eddy currents in the metal exterior part 31 are as small as possible when the antenna 32 resonates.

Thus, one practical structure for implementing the above technical idea of the present invention is: a structure is introduced such that the magnetic flux from the antenna 32 trapped in the metal exterior part 31 when the antenna 32 resonates is reduced, as an example of which is a structure in which the resistance value of at least a part of the metal exterior part 31 is different from the resistance value of another part of the metal exterior part 31.

More specifically, it may be desirable that the resistance value of a part of the metal exterior part is larger than the resistance value of another part constituting the metal exterior part.

Furthermore, the metal skin member 31 may be of a single piece type, but is preferably formed by joining at least two metal members.

In the latter case, it may be desirable to form the metal exterior part 31, for example, from a body part (sidewall part) 45 and a back cover part 41, in which case it may be desirable that the body part (sidewall part) 45 and the back cover part 41 are joined or fixed to each other, or detachably joined together at a prescribed position.

In the metal exterior part 31 of the present invention, in the case where the body part (side wall part) 45 and the back cover part 41 form an integral metal exterior part 31, it is contemplated that the body part (side wall part) 45 is formed of two or more side wall sub-parts 451, 452, and such a structure may be that the side wall sub-parts 451, 452 are joined to each other.

In the same way, the present invention has a case: the body member (side wall member) 45 and the back cover member 41 constitute a one-piece metal exterior member 31, and the body member 45 thereof is also formed of an inner body member and an outer body member. In this case, the body member 45 may be formed of an inner body member and an outer body member joined to each other.

That is, in the electronic apparatus 30 of the present invention, the joint member 39 of the exterior metal member 31 is not limited to the joint member 39 described above, and, in the main body member or the side wall member 45 of the exterior metal member 31, the joint member 39 in the present invention, which joint member 39 is provided by a stub shaft, an operation button, an operation pin, or the like penetrating the main body member or the side wall member 45 and at the inner surface of one passage hole 48 in the main body member or the side wall member 45, surrounds the connecting portion between each of the

operation processing mechanisms

33 and 34.

Reference numeral 47 in fig. 1 necessarily represents a switching circuit.

That is, in part of the body member 45, at least one insert or abutment member is provided, the insert or abutment member being selected from the group consisting of: the rod, tube, glass plate, front frame, inner positioning ring and dial opening, all of the above-mentioned joint parts, including the joint surfaces between these parts and the main body part or side wall part of the metal exterior part 31, are all candidates for the resistance value change for positioning in the present invention.

Specifically, the structure is such that: among the plurality of members constituting the metal exterior member 31, the resistance value of the metal forming one member is different from the resistance value of the metal forming the other member. For example, in the joint part 39 between the body part 45 and the back cover part 41, the joint part 39 is a contemplated joint part, and the structure is such that: the resistance value of the body member 45 is different from that of the back cover member 41, and for example, the resistance value of the back cover member 41 may be larger than that of the body member 45.

In this case, it is possible to make the metal material forming each member different.

As another example, for the structure may occur: the resistance value of the inter-joint member 39 between the plurality of members forming the exterior metal member 31 is different from the resistance value of the metal forming the exterior metal member 31.

In this particular embodiment, for example, a gap or space is provided with appropriate spacing in the engagement member 39, or the structure may be made: an intervening insertion member 49 is inserted, the intervening insertion member 49 being made of a film, a sheet, or an adhesive formed of a material having a resistance value larger than that of the metal material forming the metal exterior member 31.

In the electronic device 30 of the present invention, the method of forming the joining member 39 on the metal exterior member 31 is a suitable method for joining two metal members, and although no particular method is specified, the method used may be one or more methods selected from the following methods: bolting, internal threading, quick-connect, welding, brazing, crimping, slotted reverse taper, solid state diffusion bonding, and the like.

The method of forming the joint member 39 in the present invention is a packing clamping method, and a specific example of the packing clamping method that can be used is a packing clamping method shown in fig. 39 and is generally referred to as GN-4.

Specifically, the prior art uses the GN-4 filler clamping method as a method of clamping between the wind shield and the side wall member in an electronic device (including a timepiece), and of course, this method is also used in the present invention as a method of effecting clamping between the rear cover and the main body.

GN-4 packing is well known as a method of clamping between components to achieve high pressure water resistance, and in particular, inserting a highly elastic material 391 (e.g., made of glass) between a body 392 and a back 393 (typically made of glass)

) The method of (1), the body 392 and the back cap 393 are compressed with a highly elastic material to increase the sealability against water and the clamping force on the back cap 393, so that the dimensional accuracy and surface quality are required in filling, including the body 392, the back cap 393 and the highly elastic material (e.g., the back cap 393))。

Of course, in the present invention, although it is also possible to manufacture the back cover 393 from glass, it is particularly preferred in the present invention that the back cover 393 is not manufactured from glass, but is made from a metal material similar to the body 392.

Further, as another specific example of the packing clamping method in the present invention, a GN-7 packing clamping method as shown in FIG. 40 can be used.

The GN-7 packing clamping method is substantially similar to GN-4 packing clamping method, and is mainly used for high-quality timepieces to provide a thin high-pressure waterproof structure.

Specifically, similar to the GN-4 filler clamp method, a highly elastic material 401 (e.g., made of glass) is inserted between a body 402 and a back cover 402 (typically made of glass)

) The highly elastic material 401 is compressed between the side walls of the body 402 and the rear cover 402 to increase sealability against water and a clamping force on the rear cover 403.

As shown in fig. 40, the difference between the GN-4 packing clamping method and the GN-7 packing clamping method is that in the GN-7 packing clamping method, a groove covering member 404 is provided in an end surface portion of a joint member between a main body 402 and a rear cover 403, the groove covering member 404 covers a groove between the main body 402 and the rear cover 403, a filling material composed of a highly elastic member 401 is disposed in the groove between the main body 402 and the rear cover 403, and press-fitted, so that the filling material is extruded from between an inclined surface 405 and the groove covering member 404, the inclined surface 405 being provided at an end portion of the rear cover 403.

Also in this particular case, the present invention contemplates the use of a metallic material for rear cover 403.

Further, in the present invention, a tenon-and-mortise holding method as shown in fig. 41, which is another method of forming the engaging member 39, may be used. As shown in fig. 41, a particular example of this method is to provide a plurality of tongues 410 on the back cover 413, with the projections 415 of the tongues 410 fitting into the grooves 414 provided in the body 412, clamped between the body 412 and the back cover 413 by means of a suitable packing 411.

While fig. 41 illustrates an internal dovetail gripping method, an external dovetail gripping method may be used, wherein the structure is similar to the internal dovetail gripping method but in the opposite direction.

In the present invention, it is desirable to provide the joint member 39 as close as possible to the antenna 32, or stated differently, it is desirable to provide the antenna 32 as close as possible to the joint member 39.

Although in the present invention, the joining member 39 of the above-described structure is provided at one position on the exterior metal member 31, a plurality of joining members 39 may be provided, and in addition, it is desirable to provide the joining members 39 so as to have a predetermined width, a predetermined length, and a predetermined surface area.

Next, fig. 2 is a general sectional view showing an example of a structure of the radio-controlled timepiece 30 of the invention applied to the radio-controlled timepiece 30 which is a specific example of the electronic device 30 of the invention.

Specifically, metal exterior part 31 in fig. 2 is formed by a main body part 45 and a rear cover part 41, the main body part 45 being substantially tubular in shape, a windshield 43 being mounted on the top opening of the main body part 45, as shown in fig. 2, an inserted filler 46 being formed on a step 37a on the inner periphery of the main body part, a prescribed joining part 39 being formed between the peripheral part of the main body part 45 and the peripheral part of the rear cover part 41, the joining being performed by, for example, tight fitting, threaded engagement, or using screws on the bottom of fig. 2.

As shown in fig. 2, the back cover member 41 is mounted to the body member 45 by a screw-coupling method, and the packing 44 is fitted between its elevated portion 50 and the inner side surface 37c of the body member 45.

As shown in fig. 20 and 21, the body member 45 houses a movement 42, and the movement 42 is provided with the radio-controlled watch receiver 2, a CPU3, and a display driving section.

In the upper part of the movement 42 of fig. 2, a dial 35 (i.e., a time display part) and a hand 36 are provided. The movement 42 is positioned by the dial 35 so as to be in contact with the lower surface (as shown in the drawing) of the inner projecting portion 37b of the metallic exterior member 31 forming the step 37a, and the movement 42 is held in place by being fitted between the lower surface of the inner projecting portion 37b and the main body member 45 provided on the upper surface of the raised portion 50 of the metallic exterior member 41.

Between the movement 42 and the back cover member 41, a prescribed space 51 is provided, and the antenna 32 is disposed in this space 51. The antenna 32 is formed of a strip-shaped magnetic core material 38 and a coil 42 wound around the magnetic core material 38, and the antenna 32 is held on the lower surface of the core 42.

Both the main body member 45 and the back cover member 41 in this embodiment are made of titanium. In this particular example of the invention, the thickness of the body member 45 is set to 1600 microns and the distance from the antenna 32 to the inner surface of the body member 45 is set to 2000 microns. Further, the thickness of the back cover member 41 was set to 800 micrometers, and the distance from the antenna 32 to the back cover member 41 was set to 3000 micrometers.

In the radio-controlled timepiece constructed as described above, the CPU (not shown) in the movement 42 operates the display driving section (not shown) in accordance with the standard radio signal received by the antenna 32, so that the hands 36 can be constantly corrected. In this operation, although the main body member 45 and the back cover member 41 are made of metal in this specific example, since each of the thickness of the main body member, the thickness of the back cover member, and the distances between the antenna and the main body member and the back cover member is specified in advance in accordance with experimental data in order to obtain an optimum reception sensitivity, the interference of the resonance phenomenon in the vicinity of the antenna is reduced, and the sensitivity is improved.

If a non-magnetic metal such as gold, gold alloy, silver alloy, copper alloy, brass, aluminum alloy, zinc alloy, manganese alloy having a resistivity of 7.0 micro-ohm cm or less is mounted on the inner surface of the back cover part 41 or the inner surface of the body part 45 of the metal exterior part 31, the gain can be improved by about 2-3 db.

The following describes in detail the insertion of the insertion member 49 into the joining member 39 of the present invention.

Specifically, according to a specific example of the electronic device 30 of the present invention, the insertion member 49 is inserted into one of the plurality of members forming the metallic exterior member 31, for example, the mutual joining member between the main body member 45 and the back cover member 41, which is the case, for example, where the joining member 39 is formed at a position closest to the antenna 32, and the resistance value of the insertion member 49 is different from that of the metal forming the metallic exterior member 31.

In this case, it is desirable that the plurality of parts forming the metal exterior part 31, such as the metal parts forming both the main body part 45 and the back cover part 41, are the same, but they may be different as an alternative.

In this particular example, it is desirable that the resistance value of the material forming the insertion member 49 for insertion into the joining member 39 is selected to be larger than the resistance values of all the metal members forming the exterior metal member 31.

Although there is no limitation on the material of the interventional insert 49, it is desirably a substantially insulating substance.

The joining member 39 shown in fig. 2 and 3 may be a structure in which the insertion-type insertion member 49 as an insulator is inserted by means of the filling member 44.

If the position of the engagement member 39 in this particular example of the invention is viewed in plan view, it is desirable to locate the insertion member 49 along the entire engagement member 39, since the engagement member 39 between the main body member 45 and the back cover member 41 is generally circular, oval or rectangular.

In the present invention, in the case where the structure of the electronic device 30 can be made waterproof, it is of course also possible to provide the insertion means 49 only on a part of the periphery of the engagement means 39, for example, to provide the insertion means 49 only at one position near the antenna 32.

Thus, the insertion member 49 of the present invention is disposed and fixed between the engaging members 39.

The position of inserting the insertion-type insertion part 49 is not limited to the specific example described above, and as described above, the insertion may be effected with respect to all the engagement parts 39. For example, the intrusive insert parts 49 may be provided at a joint formed by mating together the body parts 45 and the front frame, or such as between upper and lower body parts, or at a joint between inner and outer body parts.

The intrusive insertion part 49 used in the present invention is a part formed separately from one or more parts forming the metal exterior part 31. For example, it may be a film-like member or a sheet-like member made of synthetic resin or rubber (organic substance), it may be an insulator such as an oxide or the like, or a thin film member having an oxide film, it may also be ink, paint, adhesive, or paste.

Further, the insertion member 49 used in the present invention may be one or more members forming the metal exterior member 31, which may be a thin film formed on the member contacting the joining member 39.

Specifically, such a film may be formed on one or more members forming the metal skin member 31 by an appropriate surface treatment or hardening treatment process.

The surface treatment process may be, for example, a method selected from the following methods: wet plating, dry plating, and heat treatment.

It is desirable that the resistance value of the insertion member used in the present invention is larger than the resistance values of the plurality of members forming the metal exterior member 31.

As a description of the effects of the present invention described above, in the prior art structure as described above, since the metallic exterior part 31 of the electronic device 30 is circular, the metallic exterior part 31 as shown in fig. 4(B) is formed by the main body part 45 and the back cover part 41, and the two parts are fitted and fixed to each other by the screw 52, as shown in fig. 4 (a). Thus, the engagement member 39 of the present invention is formed on the mutually mating surfaces S1 of the threads 52 and the engagement surface S2 between the main body member 45 and the back cover member 41.

Thus, the main body part 45 and the rear partThe joint member 39 formed by the joint surface S2 between the cover members 41 is circular as shown in fig. 4(a), and considering an example in which the antenna 32 is disposed near a part of the joint member 39 as shown in fig. 4(B), eddy currents 54 are generated from both ends of the magnetic core 38 of the antenna 32 as shown by arrows A, B, C0. However, as shown in FIG. 3, since the interposition insertion part 49 made of an insulator is inserted between the back cover part 41 and the main body part 45, which are in contact with each other via a part of the rubber packing 44, as shown in FIG. 4(B), any eddy current C is not generated₀Thus, the amount of eddy currents is reduced, thereby reducing energy losses.

Next, in another specific example of the electronic device 30 of the present invention, a structure is adopted in which a non-bonded portion is formed on at least a portion where the metal exterior part 31 is formed, for example, on at least a portion of the bonding part 39 between the main body part 45 and the back cover part 41, that is, more specifically, on a portion of the bonding part 39 formed at a position near the antenna 32.

In this particular example, in order to make the resistance value of the joining member 39 larger than that of the metal material forming the metal exterior member 31, a gap 55 is formed to introduce air instead of the insertion-type insertion member 49.

In this particular example of the invention, the gap 55 is formed in the joining member 39 by removing a portion of the joining surface where at least one of the least two metal members forming the joining member 39 is located.

Specifically, a gap 55 of the present invention, which is a non-contact portion, is formed by removing an appropriate width and length of a joining surface of two metal members and making them face each other to form the joining member 39.

As another alternative, in the particular example described above, a portion of the intervening insert member 49 may be removed to form the gap 55.

It may be desirable to use a gap 55 of a height of, for example, from 0.1 to 1000 microns, preferably 60 to 160 microns in this particular example.

As shown in fig. 6(a), the gap 55 is formed by removing a portion of the joint member 39 between the back cover member 41 and the main body member 45 forming the metal exterior member 31. In the specific example shown in fig. 6(a), the gap 55 is formed by removing only a part of the back cover member 41. As shown in the plan view of fig. 6(B), the gap 55 forms a non-contact portion on a portion 57 of the joining surface of the annular joining member 39.

As shown in fig. 6, it may be desirable to form the gap 55 near the antenna 32.

According to another specific example of the present invention, as shown in fig. 4(B), in the metal exterior member, for example, the main body member 45 and the back cover member 41 forming the metal exterior member 31 are engaged with each other by the screw mechanism 52, and in the case where the engaging member 39 is formed by a screw surface, the gap 55 can be formed by removing a part of the screw mechanism 52.

Specifically, as shown in fig. 7(a), the gap 55 may be formed by removing a part of the screw mechanism portion of the at least one screw mechanism 52 of the engaging member 39.

In this particular example, as shown in fig. 7(B), it may be desirable to provide the gap 55 in the vicinity of the antenna 32.

Specifically, in this specific example, the structure shown in fig. 7(a) is: a portion of the screw mechanism 52 of the body member 45 is removed so that a gap 55 is formed between the screw mechanism of the back cover member 41 and the side wall surface of the body member 45 which are mated with each other.

As shown in fig. 7(B), there is a gap 55 formed as a non-contact portion in the engaging member 39 by removing a part of the screw mechanism 52 of the main body member 45 in a part 56 of the engaging surface of the engaging member 39, which has an annular engaging surface formed by means of the screw mechanism, as indicated by viewing the figure from above.

In the particular case shown in fig. 7, it is also possible to share said gap 55 with the above-mentioned interposed element 49 and the filler element 44, although this is not shown in the figure.

In the above-described specific example using the gap 55, since the space of the gap 55 can be filled with air, there can be an effect of an insulator, which is equivalent to the case of inserting the intervention insertion member 49 in the joining member 39.

In this particular example, the insulator described above may also be inserted within the gap 55.

The gap 55 is not limited to the position shown in fig. 7, and as described above, it is apparent that the gap 55 may be applied to any position where at least two metal members having any joining structure formed in the metal exterior member 31 are joined to each other.

To confirm the above, the experimental results shown in fig. 31 are given.

In the experiment shown in fig. 31, the characteristic value of each antenna was measured at two selected frequencies, one in which a gap 55 was not formed in the joint part 39 between the back cover part 41 and the main body part 45 of the metal exterior part 31 having a ring-shaped structure (experiment 1: no notch), the second in which a gap 55 was provided in the joint part 39 in the vicinity of the antenna (experiment 2), and the third in which a gap 55 was provided in a part of the joint part 39 on the opposite side of the antenna (experiment 3).

As can be appreciated from the experimental results shown in fig. 31, although there is no great difference in the antenna characteristics with respect to the location of the gap 55, the two cases where the cut-out portions are provided show: the gain effect in the case of having the notch is superior to the case of not providing the notch, that is, superior to the case of the structure without the gap 55.

Next, the positional relationship between the insertion part 49 or the gap 55 provided in the metal exterior part 31 of the electronic device 30 or both of these parts and the antenna 32 provided in the metal exterior part 31 is described in detail.

First, although there is no particular limitation in the structure of the antenna 32 used in the present invention, it may be desirable that the antenna be a coil wound around a straight or curved magnetic core having a maximum longitudinal length smaller than the diameter of the metallic exterior member 31 as shown in fig. 1 to 7.

Of course, in the present invention, the core may be in the shape of a loop or a closed loop, and may be the antenna 32 having a structure as shown in fig. 14.

In the present invention, as described above and shown in fig. 4 to 7, it may be desirable to provide the antenna 32 near the outer periphery of the metallic exterior member 31, specifically, near the above-described joining member 39.

In the case where the antenna 32 is provided inside the metal exterior member 31, the antenna 32 may be provided virtually anywhere near the outer peripheral portion of the joining member 39 of the metal exterior member 31.

To best achieve the objects of the present invention, it may be desirable to locate the antenna 32 near the location for positioning the interventional insert 49 or the gap 55, as described in the specific examples above.

Specifically, as shown in fig. 6, the insertion-type insertion part 49 or the gap 55 of the metal exterior part 31 is continuously formed in the engagement part 56 surrounded by the sector 57; or as shown by reference numeral 60 in fig. 8(a), is formed intermittently. The sector 57 is formed by both end portions of the magnetic core of the antenna 32 having a prescribed length and the central portion of the metallic exterior member 31, and the antenna 32 is provided in the vicinity of the position where the interposing member 49 or the gap 55 is provided.

Since the length of the sector 57 is determined by the core length a of the antenna 32 and the installation position of the antenna 32, it is desirable to make the installation position of the antenna 32 within a range represented by the ratio (B/a) of the core length a of the antenna 32 and the angle between the engaging members 39.

Fig. 32(a) shows the positioning of the antenna 32 in the metal exterior part 31. Fig. 32(B) shows the relationship between the length of the gap 55 and the angle, and the length of the gap 55 is: a length B of the sector 57 in a case where the antenna 32 having the prescribed length a is moved in the direction of the gap 55 from the central portion of the metal exterior part 31. Fig. 32(C) shows an example of the ratio of the length B of the sector 57 to the length a of the antenna 32.

It will be understood in essence that for the case where no contact point is provided within the sector, and where a central angular range within the sector is expected to be 30-180 °, the angular ratio (B/a) must be 0.64-2.5; and under the same conditions, it is expected that in the case where the central angle in the sector is in the range of 50 ° to 120 °, then the angle ratio (B/a) must be 1.05 to 2.16.

Further, when the central angle in the sector is 10 ° or less, it is understood that the angle ratio (B/a) must be 0.21 or less in the case where no contact point is provided in the sector.

Therefore, by summarizing the data of fig. 32(C) and the information on the preferred angle range shown in fig. 5(B), it is possible to predict a preferred position where the antenna 32 having a prescribed length should be placed.

The angular extent of the sectors 57 in the present invention is in the range of 30-180 deg., preferably 50-120 deg., more preferably 60-90 deg..

In order to investigate the preferable range of the central angle of the sector 57 as shown in fig. 5(a), a specific example as shown in fig. 5(a) was constructed, and the condition of the change of the antenna gain (decibel) was measured while changing the central angle (θ) of the sector 57 in which the screw groove was removed as shown in fig. 6(a), and the result was shown in fig. 5 (B).

As is clear from the graph of fig. 5(B), since the gain (decibel) of the antenna 32 increases as the angle of the removed area of the engagement member 39 in the threaded portion increases, it can be understood that the effects of the present invention can be achieved within the angular range of interest, which is preferably 60-90 °.

In the specific example of the present invention shown in fig. 8(a), in the above-mentioned sector 57, the antenna characteristics obtained in the case where the whole of the engaging member 39 formed at the central angle of 120 ° or the whole of the screw groove formed in the same region is removed entirely, and the antenna characteristics obtained in the case where the part of the screw groove included in the above-mentioned sector 57 is left without being removed therefrom (particularly, the screw groove positioned in the region determined by the central angle of 10 °, which is produced by extending the two end edge lines 5 ° to the left and right, respectively, from the center line of the sector 57) are compared with the antenna characteristics obtained by the conventional method, i.e., without providing the removed portion or without providing the cut-out portion or without inserting the interposing interposition member 49 in the whole of the engaging member.

From this comparison, it can be seen that although there is a significant effect in the former structure as compared with the former structure, on the other hand, although there is some effect in the latter structure as seen in the former structure, the effect of the latter structure is small as compared with the former structure but is very practical.

As described above, in the present invention, it is possible to provide the antenna 32 at a position corresponding to the above-described sector 57.

Next, a preferred structure of the antenna 32 used in the present invention will be described.

Specifically, the antenna 32 used in the present invention is substantially a strip antenna, and it is preferable that the inductance value of the antenna is 1600 millihenries or less, and the resistance value of the antenna coil is 1 kilo-ohm or less, and further, it is desirable that the number of turns of the antenna coil is 1000 or more.

A preferred specific example of the antenna structure of the present invention is described in detail below.

Specifically, fig. 9 shows a schematic plan view of a specific example of the antenna 32 of the present invention, which shows the antenna 32 capable of receiving a radio signal and provided in a timepiece constituted by a side wall member 44 and a back cover member 41 made of metal.

In the above-described conventional example, in the case where an antenna is provided in a metal exterior member having a metal side wall or a metal cover, since the metal exterior member hinders a resonance phenomenon (a change in magnetic flux to a change in electric power to magnetic energy) generated by the antenna, specifically, since magnetic lines of force generated by the resonance phenomenon are absorbed in the metal member, eddy currents are induced therein, and as a result, almost all the magnetic lines of force are consumed (due to iron loss), so that the gain and Q value of the antenna are greatly reduced, which shows a problem of a radio controlled timepiece in which the antenna is inside the metal exterior member.

In general, although the gain increases as the number of turns of the coil increases, it is understood that when the number of turns reaches a certain number, the resistance (copper loss) of the coil becomes large and the gain decreases.

Specifically, since the output of the antenna is composed of an output conforming to faraday's law and an output of a resonance phenomenon in the antenna, when the antenna is placed in a metal exterior part, the gain is also greatly reduced because the Q value is significantly lowered.

Stated differently, the antenna is not generally located near the metal object, and almost all of the gain obtained from the antenna is due to the resonance phenomenon described above, which increases the coil resistance (copper loss) of the antenna coil, hampers the progress of the resonance phenomenon, and results in a decrease in gain (Q value), so that it is not possible to use a very large number of coil turns, or to make the wire of the coil too thin.

In contrast, in the case of placing the antenna in a metal exterior part, since iron loss (metal exterior part) is large, the reduction of the Q value is large, and the reduction of the gain is large.

For this reason, the inventors of the present invention conducted an investigation of a method of improving antenna gain, in which it is assumed that: when the antenna is placed inside a metal exterior part, the Q value is inevitably reduced.

Specifically, in the present invention, when the antenna is placed inside a metal exterior member, as a result of an effort to determine how the obtained gain is likely to be maximized, the gain is increased not only by the Q value (resonance) as in the past but also sufficiently by faraday's law.

In order to confirm the above technical idea, the present inventors first conducted experiments to measure the relationship between the inductance L value (millihenry) and the gain (decibel) of a specific antenna, as shown in fig. 10.

Specifically, a curve a in fig. 10 shows a relationship between the inductance value L and the gain (decibel) at the time of receiving 77.5 khz in the case where a specific antenna is not inserted into the exterior metal member, and a curve B shows a relationship between the inductance value L and the gain (decibel) at the time of receiving 77.5 khz in the case where an antenna of the same structure is inserted into the exterior metal member 31.

In this experiment, a coil was wound on a conventional straight magnetic core using a known method, and the change in the inductance value L was adjusted by changing the number of coil turns and changing the coil resistance.

As can be understood from fig. 10, it has been found that, in the antenna not placed in the metal exterior part, although the gain increases with an increase in the inductance value L, when the inductance value L exceeds 10 millihenries, the gain gradually saturates. However, for the antenna inserted into the metal exterior part, the above-described saturation phenomenon does not occur, and the gain linearly increases in proportion to the increase in the inductance value L.

That is, the above experimental results show that, although the gain accompanying the resonance phenomenon has a significant drop in the case of placing the antenna in a metal exterior member, it is only an extremely small attenuation value with respect to the gain due to faraday's law.

After another investigation, the inventors determined that, from the results shown in fig. 10, with the antenna 32 used in the metal exterior member, since the gain increases linearly with the increase in the inductance value, the number of coil turns and the inductance value L that can be expected become large.

However, when the number of turns of the coil becomes large, since the capacitance of the antenna itself increases, there is a limit imposed by the resonance point of the antenna, which inevitably produces an upper limit.

As described above, the present inventors made a judgment: if the capacitance value of the antenna coil is normally approximately 10pF and since the lowest frequency used is 40 khz, the inductance value L of the antenna 32 is 1584 and 1600 millihenries calculated from the equation f 1/2 pi vlc, and therefore 1600 millihenries or less is desirable.

In practice, if we consider that the parasitic capacitances of the substrate and the integrated circuit are included in addition to the capacitance of the antenna coil, and since the inductance value L is determined to be from 792 and 800 millihenries in the case where the parasitic capacitance that can be expected is about 20pF, it is expected to use an antenna having an inductance value L of 800 millihenries or less.

Furthermore, if it is considered that the highest frequency currently in practical use is 77.5 kilohertz (germany), and the decision is made on the assumption used in this frequency band: the inductance value L of the antenna 32 in those cases determined from the above capacitance values and frequencies may be approximately 211-220 millihenries, and it is also contemplated to use an antenna 32 having an inductance value L of 220 millihenries or greater.

Further, it is contemplated that the lower limit of the inductance value L of the antenna 32 of the present invention is about 20 millihenries.

Although the minimum output required for the antenna depends on the capacitance of the receiving integrated circuit, it is expected that if the minimum output required for the antenna is 50 db, the lower limit of the inductance value L from fig. 10 is expected to be 25 mh; the lower limit of the inductance value L obtained from fig. 10 is expected to be 20 millihenries if the minimum output required for the antenna is 51 decibels, and is expected to be 15 millihenries if the minimum output required for the antenna is 52 decibels.

If it is considered that the inductance value L of the antenna in the prior art radio-controlled timepiece is 2-13 millihenries at most, it is considered that the inductance value L considered to be preferable in the above invention should be a special value.

Next, we examined the relationship between the number of coil turns (turns) and the antenna gain (decibel), and the result of this examination is shown in fig. 11.

Specifically, in fig. 11, similarly to the experiment in fig. 10, curve C shows the relationship between the number of coil turns (turns) and the antenna gain (decibels) at 77.5 khz reception in the case where a specific antenna is not inserted into the exterior metal part; curve D shows the relationship between the number of coil turns (turns) and the antenna gain (decibel) at 77.5 khz reception with the same configuration of antenna inserted into the metallic cover 31.

As can be understood from fig. 11, it can be seen that in the antenna which is not put in the metal exterior part, although the gain increases as the number of turns (turns) of the coil increases, the gain gradually saturates when the number of turns of the coil exceeds 1000. However, for an antenna inserted into a metal exterior part, the above-described saturation phenomenon does not occur, and the gain linearly increases in proportion to an increase in the number of turns (turns) of the coil.

Therefore, in the present invention, it can be concluded that in the radio-controlled timepiece in which one or both of the side wall and the back cover of the exterior part are metal, the number of coil turns (turns) of the antenna 32 can be expected to be 1000 turns or more.

Further, as can be understood from fig. 11, in the case where the antenna 32 is used alone without being put into a metal exterior member, when the number of turns (turns) of the coil is 1500 or more, the gain is saturated. Of course, in the case where the antenna 32 is put into a metal exterior member, even when the number of coil turns (turns) is 1500 or more, the gain is increased, and in a radio-controlled timepiece in which one or both of the side wall and the back cover are metal, a judgment is made: if the number of coil turns of the antenna 32 is 1500 or more, the antenna is more effective.

However, when the number of turns (turns) of the coil of the antenna is increased, there is a limit to the number of turns (turns) of the coil because the resistance value of the antenna is also increased.

As given above, the present inventors completed an experiment as shown in fig. 12, which was performed similarly to the experiment as shown in fig. 10, under the condition that a specific antenna was not inserted into the exterior metal part, and plotted a curve E of a relationship between a coil resistance (ohm) and a gain (db) of the antenna 32 when receiving a radio signal of 77.5 khz.

In addition, the present inventors have described the same relationship F when receiving a radio signal of 77.5 khz under the condition that an antenna having the same structure as described above is inserted into a metal enclosure.

Curve G depicts the relationship between the coil resistance (ohms) and the gain (decibels) of the antenna 32, and the relationship between the coil resistance (ohms) and the gain differential of the antenna 32, which is the difference between the gain obtained when the antenna is near a metal skin component and the gain obtained when the antenna is not near a metal skin component.

In the experiment shown in fig. 12, the coil resistance (ohm) was adjusted by appropriately combining the resistance values shown in fig. 12 (B).

As can be understood from fig. 12(a), even if only the antenna 32 without the metal exterior member is used, and even in the case where the antenna 32 is provided in the metal exterior member, the gain is reduced as the coil resistance value (ohm) increases.

When looking at curve G (curve G representing the gain difference between curves E and F above), we can see that when the coil resistance value (ohm) reaches or exceeds 1 kilo-ohm, there is no change in the gain difference between the case of using a metal skin component for the antenna 32 and the case of using the antenna in a metal skin component, which is constant in the region of about 3-4 db.

Unlike the past thought, in the case where a metal object having conductivity is placed near the antenna or in contact with the antenna in order to receive a radio signal, the radio signal is absorbed by the metal object, with the result that the radio signal does not reach the antenna, thereby reducing the resonant output of the antenna and lowering the Q value; as compared with such past thought, the results of effective investigations conducted by the present inventors are: the above understanding of this problem in the past was wrong, and even in the case where a metal object having electrical conductivity was placed near or in contact with the antenna, the radio signal had substantially reached the antenna, and in the case of non-resonance, although the flow of magnetic flux caused by an external radio signal trying to enter the timepiece was somewhat attenuated (e.g. about 3 db), the radio signal had reached the antenna without being impeded, and this has been confirmed to be true.

The problems are that: when the antenna resonates, the magnetic lines (magnetic flux) leaving the antenna core are pulled back to the metal object, and eddy currents are generated in the metal object, thereby causing attenuation of magnetic energy, reducing the output of the antenna, and making normal reception impossible.

It has been found by means of the detailed description of the above-mentioned problems in fig. 4 that, for example, in the case of placing the antenna 32 in the metal exterior part 31 of the timepiece 30 having the metal-made back cover and attempting to receive a radio signal, although the flow of the magnetic flux J caused by the radio signal attempting to enter the electronic timepiece 30 is somewhat attenuated (for example, about 3 db), the radio signal has reached the antenna 32 without being hindered, the antenna 32 has received the magnetic flux of the radio signal, and the resonant flow of the magnetic flux A, B, C outputted from both ends of the magnetic core 38 of the antenna 32 when the antenna is resonant, that is, when there is a mutual substitution between electric energy and magnetic energy₀And is pulled back into the metal exterior part 31, the metal exterior part 31 being made of a metal material, eddy currents are generated in the metal exterior part 31, thereby causing resonant magnetic flux flowThe absorption of the energy of the mover 7 results in a reduction in the resonant output of the antenna 32.

That is, if the characteristic value of the antenna 32 is defined as a Q value, since the Q value represents the ratio of the output to the input of the antenna, and Q100 represents the output characteristic of the effect that the output is 100 in the case where the input is 1; the higher the Q value, the more excellent the antenna performance is considered to be.

That is, the higher the Q value, the better the antenna performance is considered, or stated differently, the Q value is an index of the magnitude of the energy loss.

A specific example of a method which can be used for measuring the Q value is described, for example, in the specification of Japanese patent application 2002-264985, which was filed by the present inventors.

As can be seen from the above results, if the value of the coil resistance (ohm) is 1 kiloohm or less, since it can be expected that: the contribution of the coil resistance value to the gain effect of the antenna 32 used in the metal exterior member is certainly larger than that of the antenna 32 without using the metal exterior member, so that the coil resistance (ohm) value of the antenna 32 used in the present invention is expected to be 1 kiloohm or less.

In general, the thickness of the timepiece is considered to be about 10mm, and 25000 turns is a limit value of the number of turns of the coil in the case where the width of the antenna coil is 20mm, the thickness of the coil core is 1mm, the wire and conductor diameters of the coil wire are 60 micrometers and 65 micrometers, respectively, and the coil resistance is considered to be about 1 kiloohm.

More precisely, replacing the number of coil turns in the data of fig. 10 with the coil resistance values of these samples shown in fig. 13, and combining the data of fig. 13 with that of fig. 12, plot H the relationship between the coil resistance (ohm) value and the gain (decibel) of the antenna 32 when receiving a radio signal of 77.5 khz, without the antenna 32 being placed inside the metal skin 31; and plots the value of the coil resistance (ohms) against the gain (decibels) of the antenna 32 when receiving a 77.5 kilohertz radio signal, with the antenna 32 inside the metal skin.

These curves H, I are substantially the same as the curves E, F of fig. 12.

A curve J in fig. 13 represents the relationship between the coil resistance (ohm) value and the gain (decibel) of the antenna 32 when receiving a radio signal of 77.5 khz in the case where the antenna 32 is inserted into the metal exterior part 31. The number of coil turns was changed from 1000 turns to 2000 turns and shows an improvement in gain as the number of coil turns was increased.

The curve K is a curve approximately fitted to the curve J.

Curve M acts as a curve representing the balance between the rate of gain reduction due to an increase in the value of coil resistance (ohms), as shown by curve I, and the rate of gain increase due to an increase in coil resistance due to an increase in the number of coil turns (turns).

As is clear from the curve M of fig. 13, when the coil resistance (ohm) is greater than about 396 ohms, the balance between the increase and decrease of the gain is saturated, so that it can be understood that the effect cannot be achieved by increasing the coil resistance (ohm) to be more than 400 ohms.

Therefore, it is desirable that the coil resistance (ohm) of the antenna 32 in the present invention be 400 ohm or less.

Further, in the present invention, in the case of using a metal exterior member, if it is considered that the use of the antenna 32 is most effective in a region where the gain is not only high but also has little variation, it is expected and, as can be seen from the curve F in fig. 12, it is expected that the coil resistance (ohm) of the antenna 32 is used under the condition of 100 ohm or less.

It may also be desirable for the lower limit of the coil resistance (ohms) of the antenna 32 to be about 18 ohms.

Specifically, if the minimum output required for the antenna is-51 db, then as can be seen from fig. 11, the number of coil turns is 1400 turns; further, for a commonly used coil, the wire diameter thereof is 110 μm, the diameter of a conductor wound on an antenna is 100 μm, the width of a winding portion of the antenna is 20mm, the thickness of a core is 1mm, and the resistance is 18 ohm; this resistance becomes 22 ohms for a wire diameter of 85 microns and a conductor diameter of 80 microns; this resistance becomes 30 ohms for a wire diameter of 70 microns and a conductor diameter of 65 microns; for a wire diameter of 65 microns and a conductor diameter of 60 microns, this resistance becomes 38 ohms, taking this resistance range as a limit.

The coil resistance (ohm) of the prior art radio controlled timepiece antenna is only about 20 ohm, whereas the value of the coil resistance (ohm) used in the present invention is significantly larger than this value.

As can be seen from the above experimental results, in the case of placing the antenna 32 in the exterior metal member of the present invention, the decrease in the Q value is extremely small even if the coil resistance (copper loss) of the antenna increases, or put another way, the changes in the Q value and the gain G are extremely small even if the wire diameter is small and the number of turns is the same.

The antenna gain of the antenna 32 is improved by increasing the number of turns of the coil.

Accordingly, in the case of placing the antenna in a metal exterior member, the gain can be improved by making the wire of the coil thin and increasing the number of turns of the coil.

In the condition that the antenna 32 of the related art is not inserted into the metal exterior part, although a better gain can be obtained in the case where the coil wire diameter is large (e.g., the coil wire diameter of 0.1 mm) with a smaller resistance value than in the case where the coil wire diameter is small (e.g., the coil wire diameter of 0.06 mm) with a larger resistance value, as in the case where the antenna 32 is placed in the metal exterior part in the present invention, there is no difference in the gain characteristic.

Therefore, in the present invention, it is desirable that the structure of the antenna 32 has a thin coil wire, and therefore the antenna 32 can be formed in a smaller size.

Therefore, according to another embodiment of the antenna of the present invention, it may be desirable that the coil wire diameter is 0.1mm or less, preferably 0.06mm diameter.

Although the above-described antenna 32 is essentially an antenna of a form in which a prescribed number of turns (turns) of coil wire is wound around a generally flat antenna core portion, the antenna 32 is not limited to this structure and may be applied to any form of antenna, in particular, to the structure disclosed in japanese patent application 2002-.

Further, in the present invention, the structural relationship and the positional relationship between the antenna 32 and the metal exterior part 31 are important factors.

Accordingly, preferred structural and mutual positional relationships between the antenna 32 and the metal skin 31 are described in detail below.

Specifically, according to the electronic device 30 of the present invention, it is contemplated that, among the relationships between the metal exterior part 41 and the antenna 32 accommodated in the closed space, the main body part thickness of the metal exterior part (such as the thickness of the main body part 45 or the thickness of the back cover part 41) and the distance from the antenna to the main body part 45 or the back cover part 41 are established in accordance with the reception sensitivity.

If the thickness of the main body part or the thickness of the back cover part 41 and the distance from the antenna to the main body part 45 or the back cover part 41 have been established in accordance with the reception sensitivity, since it is possible to reduce the disturbance of the resonance phenomenon caused by the metal material in the vicinity of the antenna, the reception sensitivity can be improved even for the metal exterior part. By doing so, even for a radio controlled timepiece, it is possible to make the main body member, the back cover member, the front frame, and the like using titanium, stainless steel, or the like, and therefore, it is possible to improve the function of the radio controlled timepiece in terms of mechanism and appearance without reducing the receiving sensitivity.

Further, it is possible to achieve further improvement of the reception sensitivity by means of the material of the main body member 45 or the back cover member 41, the shape of the back cover member, the positional relationship between the antenna 32 and the main body member 45 or the back cover member 41, and by adding a non-magnetic material or the like. The most effective values for the thickness of the body part or back cover part and the distance from the antenna to the body part or back cover part were determined by repeated experimental verification.

The following references specifically describe the structure of the antenna 32 of the metallic exterior member 31 used in the present invention.

First, in order to investigate the relationship between the reception sensitivity and the wristwatch case, as shown in fig. 15(a) and 15(B), a main body part thickness T1 of the main body part 45, a distance D1 between the antenna 32 and the inner surface of the main body part 45, a back cover part thickness T2 of the back cover part 41, and a distance D2 from the antenna 32 to the inner surface of the back cover part 41 were selected as parameters, and the relationship between these 4 parameters and a gain, which is the peak height of the signal received by the antenna 32, was experimentally determined.

The body member 45, the antenna 32, and the back cover member 41 used in each experiment to be described below were made for these experiments, and their shapes were suitable for use in the electronic apparatus 30 (including a timepiece).

The body member 45 and the back cover member 41 are selected from the following materials: stainless steel, titanium alloy, gold alloy, silver alloy, copper alloy, brass, aluminum alloy, zinc alloy, manganese alloy, super hard alloy (an alloy comprising tungsten carbide and titanium carbide); also, in all the experiments, although there was a difference of several decibels from top to bottom, stainless steel was used as a representative member used in the case of using the main body member 45 and the back cover member 41 (because austenitic stainless steel such as SUS304, SUS304L, SUS316L, etc. is preferable) since there was no substantial change in the relationship of the gain with respect to any parameter (curve shape) in all the experiments below.

According to a first experiment, the gain of the received signal was measured while varying the body part thickness T1 from 0 to 5000 microns. In this experiment, an experimental antenna having a coil with 1500 turns and a conductor diameter of 65 μm was used, the antenna was placed in the body member 45, the distance between the body member 45 and the antenna 32 was set to a constant value of 1000 μm, and the thickness used for the back cover member 41 was 800 μm. The experiment was started by setting the distance between the antenna 32 and the back cover member 41 to a constant value of 100 μm and transmitting a signal of 40 khz from a transmitting antenna installed at a prescribed position.

The results of the above experiments are shown in fig. 16, where the gain of the received signal gradually decreased from-50 db as the body member thickness T1 increased from 0 micron (i.e., in the absence of the body member 45), and the decrease was saturated as the body member thickness T1 reached 5000 microns. The solid line shown in fig. 16 is an approximate curve determined from experimental data.

According to a first experiment it has been found that when the body part thickness T1 exceeds 5000 microns, the gain reduction reaches saturation and becomes constant, the value being the minimum. For this reason, if the body member thickness T1 is set to 0 to 5000 μm, it is possible to improve the gain with respect to the above-described minimum value. Within the above range, if considering the strength practically usable as a watch case, it is preferable to set the body member thickness T1 to the range of 300 μm to 5000 μm, which is the largest practical value. In order to form the most suitable body member in consideration of the appearance, workability, corrosion resistance, and the like of the housing of the electronic device 30, that is, the metal exterior member, it is preferable to set the body member thickness T1 to the range of 500 to 2000 μm.

According to a second experiment, the gain of the received signal was measured while varying the distance D1 between the antenna 32 and the body member 45 to be between 0 and 40000 micrometers. Fig. 17 shows the results of the above experiment from 0 to 20000 microns. In this experiment, an experimental antenna having an antenna coil of 1500 turns and a conductor diameter of 65 μm was used, the antenna was placed in the main body member 45, the thickness used for the main body member 45 was 2000 μm, the thickness used for the back cover member 41 was 800 μm, the distance from the antenna 32 to the back cover member 41 was set to a constant value of 100 μm, and a signal of 40 khz was radiated from a transmitting antenna installed at a prescribed position, whereby the experiment was started.

The results of the above experiments have shown that as the distance D1 increases, the gain of the received signal gradually increases from-54.5 db at a distance D1 of 0 microns (this condition is the case where part of the antenna 32 is in contact with the body member 45), as shown in fig. 17. In this experiment, since the gain of the received signal is-50.34 db when only the back cover part 41 is used (i.e., the case where the main body part 45 is removed), the gain increase at the distance D1 between the antenna 32 and the main body part 45 reaches saturation when the gain is gradually increased to this value. The distance D1 at which the gain is saturated in this way is 40000 μm, and further moving the antenna 32 away from the body member 45 does not cause an increase in gain. The solid line shown in fig. 17 is an approximate curve determined from experimental data.

According to the second experiment, it has been found that, although the gain is also increasing and the reception sensitivity becomes better and better as the distance D1 between the antenna 32 and the main body part 45 is increased, when the distance D1 exceeds 40000 μm, the increase in gain reaches saturation and the gain becomes constant.

For this reason, if the distance D1 is set in the range of 0 to 40000 μm, it is possible to improve the gain. Within the above range, if the size and the like actually used in the watch case are taken into consideration, it is preferable to set the distance D1 within the range of 500-10000 μm.

According to a third experiment, the gain of the received signal was measured while varying the back cover thickness T2 to be between 0 and 5000 micrometers. FIG. 18 shows the results of the above experiments at 0-3000 microns. In this experiment, an experiment was conducted by using an experimental antenna 32 having an antenna coil with 1500 turns, a conductor diameter of 65 μm, a distance from the antenna 32 to the back cover member 41 set to a constant value of 1000 μm, a thickness of the main body member 45 used was 2000 μm, a distance from the antenna 32 to the main body member 45 was set to 1000 μm, and a signal of 40 khz was radiated from a transmitting antenna mounted at a prescribed position.

From the results of the above experiment shown in fig. 18, it can be understood that the gain of the received signal is drastically reduced when the thickness T2 of the back cover member 41 is changed from 0 micrometers (which is a condition where the gain is about-43.4 db without the back cover member 41) to 800 micrometers, while it can be understood that the gain is not so greatly changed when the thickness T2 of the back cover member 41 is changed from 800 micrometers to 5000 micrometers. That is, it has been found that the minimum value occurs when the thickness T2 of the back cover member 41 is 800 micrometers. The solid line shown in fig. 18 is an approximate curve determined from experimental data.

In practical use, the above-mentioned minimum value does not represent any problem, and, in the above-mentioned range, in view of the practical strength of the metal exterior part 31 of the electronic device 30, it is preferable to set the back cover part thickness T2 to a range from 100 micrometers to a value of 5000 micrometers, where a maximum value can be generated. In order to form the most suitable back cover in consideration of the appearance, workability, corrosion resistance, and the like of the metal exterior member 31, it is preferable that the back cover member thickness T2 be set in the range from 300 to 2000 μm.

According to the fourth experiment, the gain of the received signal was measured while changing the distance D2 between the antenna 32 and the back cover member 41 to be between 0 and 5000 micrometers. In this experiment, the experiment was started by using the experiment antenna 32, the antenna coil having 2000 turns, the conductor diameter being 65 micrometers, the thickness used for the main body member 45 being 2000 micrometers, the thickness used for the back cover member 41 being 800 micrometers, the distance from the antenna 32 to the main body member 45 being set to a constant value of 1000 micrometers, and a signal of 40 kilohertz was emitted from the transmission antenna mounted at a prescribed position.

As a result of the above experiment shown in fig. 19, when the distance D2 was increased, the gain of the received signal was gradually increased from 0 μm (which is the case where part of the antenna 32 was in contact with the back cover member 41), and the gain under this condition was-49.6 db. In this experiment, since the gain is-38.8 db in the case where only the main body part 45 is used (i.e., the case where the back cover part 41 is removed), the increase in gain reaches saturation at the distance D2 formed between the antenna 32 and the back cover part 41 as the gain is gradually increased to this value.

The distance D2 at which the gain is increased to saturation in this way is 5000 microns, and the antenna 32 is further away from the back cover part 41 without an increase in gain. The solid line shown in fig. 19 is an approximate curve determined from experimental data.

According to the fourth experiment, although the gain is also increased when the distance D2 from the antenna 32 to the back cover member 41 is increased, resulting in excellent reception sensitivity, the increase in gain is saturated when the distance D2 exceeds 5000 μm. For this reason, if the distance D2 is set in the range of 0 to 5000 micrometers, the gain can be improved. Within the above range, if the size or the like actually used in the watch case is taken into consideration, it is preferable to set the distance D2 within the range from 100 to 700 μm.

Next, a specific example of the electronic device 30 of the present invention is described with reference to fig. 2 and based on the above experimental results.

Fig. 2 is a sectional view showing a radio controlled timepiece of the invention, the basic structure of which has been described above.

A prescribed space 51 is provided between the movement 42 and the rear cover 41, and the antenna 32 is disposed in this space. The antenna 32 is fixed to the lower surface of the movement 42.

In the present invention, the antenna 32 may be designed to be in contact with the inner surface of the metal exterior part 31, and as an alternative, the antenna 32 may be provided in a space between the antenna 32 and the inner surface of the metal exterior part 31.

In this specific example, austenitic stainless steel (such as SUS316) is used for both the main body member 45 and the back cover member 41. According to the above experimental results, the thickness of the body member 45 was set to 1600 micrometers, and the distance between the antenna 32 and the inner surface of the body member 45 was set to 2000 micrometers. The back cover member thickness of the back cover member 41 is designed to be 800 micrometers, and the distance from the antenna 32 to the inner surface of the back cover member 41 is set to 3000 micrometers.

In the electronic device 30 configured as described above, the CPU in the movement 42 operates the display driving section to drive in accordance with the radio signal received by the antenna 32, so that the hands 36 can be always corrected. In doing so, although the main body member 45 and the back cover member 41 are made of metal in this specific example, since each set value among the main body member thickness, the back cover member thickness, and the distances between the antenna 32 and the main body member 45 and the back cover member 41 is a value obtained from the experimental result that the optimum reception sensitivity can be obtained, the interference of the resonance phenomenon in the vicinity of the antenna is reduced.

Further, if a non-magnetic material such as gold, gold alloy, silver alloy, copper alloy, brass, aluminum alloy, zinc alloy, manganese alloy is provided on the inner surface of the back cover member 41 or the inner surface of the main body member 45 of the metal exterior member 31, and their specific resistance is 7.0 micro ohm · cm, it is possible to improve the gain by about 2 to 3 db.

Further, a hardening treatment such as a carburizing treatment may be performed on one or both of the main body member 45 and the back cover member 41 without any reduction in gain, which can be described by the performance of the carburizing treatment.

In another specific example of the present invention different from the above specific example, although the basic structure shown in fig. 2 is the same, the materials of the main body member 45 and the back cover member 41, the thickness of the main body member 45, the distance between the antenna 32 and the main body member 45, the thickness of the back cover member 41, and the distance between the antenna 32 and the back cover member 41 are set to be different from the above specific example.

Specifically, in this particular example, the main body member 45 and the back cover member 41 are formed of titanium.

For the case where both the main body member 45 and the back cover member 41 are made of titanium, if a standard for high-pressure waterproofing is adopted, the main body member thickness is set to a thickness of 2000 μm, and in the same manner, the back cover thickness is set to 1000 μm.

Since there is a relationship with the materials of the main body member 45 and the back cover member 41, even if the distance between the antenna 32 and the main body member 45 and the back cover member 41 is small, since it is possible to obtain a reception sensitivity that is not problematic, it is possible to set the distance between the antenna 32 and the main body member 45 to 500 micrometers and the distance between the antenna 32 and the back cover member 41 to 400 micrometers.

Also for this specific example, if a non-magnetic material is provided on the inner surface of the back cover part 41 or the back surface of the body part 45, it is possible to improve the gain by about 2-3 db, similarly to the case of the above specific example.

In this particular example, there may also be a hardening treatment, such as a nitriding treatment, on one or both of the body member 45 and the back cover member 41, without any reduction in gain, as may be dictated by the performance of such hardening treatment.

Another specific example of the radio controlled timepiece of the invention shown in fig. 22 has substantially the same structure as that shown in fig. 2, but different materials are used for the main body member 45 and the back cover member 41.

Specifically, in the structure of fig. 2, the main body member 45 and the back cover member 41 are made of brass, and then they are mirror-polished, after which, as shown in fig. 22, plating

layers

221, 222 of Pd or the like are formed thereon by wet plating, thereby polishing them. Brass is a non-magnetic material having a resistivity value of 7.0 micro ohm cm or less, which is experimentally confirmed to produce excellent reception sensitivity conditions, and this set value is used together with a set value of the thickness of the body part to improve reception sensitivity.

The body member 45 and the back cover member 41 of this specific example were the same as those of the above specific example except that the plating was performed, and the body member thickness was set to 1600 μm and the back cover member thickness was set to 800 μm. The distance between the antenna 32 and the main body member 45 is set to 2000 micrometers, and the distance from the antenna 32 to the back cover member 41 is set to 3000 micrometers.

The plating layers 221, 222 of the main body member 45 and the back cover member 41 are formed by a wet plating method as described below.

First, in order to form a lower layer to be plated, in a plating bath (composition: Na)₂SnO₃.3H₂O60 g/l (g/l), CuCN 20g/l, K₂SO₃H10 g/l, KCN (optional) 30g/l, KOH 60g/l, Zn (CN)₂5g/l) of the

body parts

300 and 301 were plated at a temperature of 50 ℃ and a current density of 2.4A/dm²pH 12.5, precipitation rate 0.33 micron/min for 6 minutes. By doing so, an under-plating layer of Cu-Sn-Zn alloy is formed on the surfaces of the

body members

300 and 301 to a thickness of about 2 μm.

Then, an Sn-Cu-Pd alloy was formed on the lower plating layer under the following conditions. Electroplating bath: (composition: Na)₂SnO₃·3H₂O60 g/l (equivalent to an amount of Sn of 26.7 g/l), CuCN 20g/l (equivalent to an amount of Cu of 14.2 g/l), K₂SO₃H10 g/l, KCN (optional) 30g/l, KOH 60g/l, K₂Pd(CN)₄3H2O 30g/l (equivalent to an amount of Pd of 9.3 g/l)). Conditions of electroplating are as follows: the temperature of the cell is 50-55 ℃, and the current density is 2.0A/dm²Current efficiency was 47.8%, PH 12.5, precipitation rate 0.33 micron/min, time 9 min. By such plating, an Sn-Cu-Pd alloy having a hardness (Hv) of about 300 and a density of 9.6g/cm and having a thickness of about 3 μm was formed on the lower plating layer³. After simple quantification of the composition of the coating using a scanning electron microscope and an X-ray micro analyzer, it was confirmed that the composition was a three-element alloy consisting of, by weight, 17.12% Sn, 44.22% Cu, and 38.66% Pd.

After the above step, the plating was further performed on the Sn-Cu-Pd alloy plating layer using the following conditionsAnd forming a polished plating layer. Plating bath: (Parabiright SSS (product name) of pure chemical Co., Ltd., Japan). Electroplating conditions are as follows: the temperature is 55 ℃ and the current density is 1.5A/dm²pH 7.6, precipitation rate 0.33 micron/min, time 6 minutes. By such plating, a Pd plating layer having a white luster and a thickness of about 2 μm is formed, thereby completing the plating layers 221 and 222.

The body member 45 and the back cover member 41, on which the above-described plating layers 221, 222 were formed, were immersed in a synthetic solder oil for 24 hours, and then subjected to a corrosion resistance test, without exposing a surface color, with good corrosion resistance. Wherein the components of the welding oil comprise 9.9g/l of sodium chloride, 0.8g/l of sodium sulfate, 7.1g/l of urea, 0.19g/l of ammonium hydroxide, 0.2g/l of cane sugar and 0.8g/l of lactic acid (50%). The body member 45 and the back cover member 41 never peel off even when subjected to a heating test at 200 ℃ for 5 hours, and therefore have good heat resistance.

Also in this specific example, although the main body part 45 and the back cover part 41 are formed of metal, since each of the main body part thickness, the back cover thickness, and the distance between the antenna 32 and the main body part 45 and the back cover part 41 is based on the experimental result that the optimum reception sensitivity can be achieved, interference with the resonance phenomenon in the vicinity of the antenna is minimized, and the reception sensitivity is improved. Further, since the surface treatment is performed to the body member 45 and the back cover member 41, corrosion resistance and heat resistance required for use as a radio-controlled timepiece are provided, and since white gloss having a sense of weight and high texture is provided, a high-quality appearance is obtained as a result.

In all of the above-described specific examples, as shown in the back cover member 41 of fig. 22, if the inner surface of the back cover member 41 is made flat without a protruding portion and the shape of the secondary plane is provided to the back cover member 41, it is possible to reduce interference with the resonance phenomenon in the vicinity of the antenna 32 and to improve the reception sensitivity by about 2 db as compared with the case where the protruding portion is present.

In order to realize a more compact and thinner timepiece, the direction of the antenna 32 may be additionally considered, and the distance between the antenna 32 and the main body member 45 or the back cover member 41 may be made 0.

Further, the directivity of the antenna 32 may be considered when the antenna 32 is disposed so that the outer surface of the antenna 32 is parallel to the inner surface of the main body member 45 or the inner surface of the main body member 45, or when the antenna 32 is disposed so that one end surface of the antenna is substantially upright perpendicular to the inner surface of the back cover member 41.

Although the metallic exterior member 31 in the above-described specific example is formed by the body member 45 and the back cover member 41, a front frame or a ring may be provided on the top of the body member 45. Further, if any one of the main body, the front frame and the back cover member is formed of a non-metallic material, it is possible to further improve the reception sensitivity. By separating the front frame or the like from the main body member 45, it is possible to improve the reception sensitivity.

If not all of the main body part, the front frame and the back cover part are formed of a non-magnetic material, even if a part of them is formed of a non-magnetic material, the reception sensitivity can be improved.

In the above case, it is effective and preferable that a portion of the antenna 32 protruding in a planar manner or only an end portion of the antenna 32 is made of a non-magnetic material.

It may be the case that not only one type of metal and non-magnetic material is used, but a combination of multiple types of metal and non-magnetic materials may be used.

Similarly to the experiment described above, among the materials selected for the main body part 45 and the back cover part 41, an antenna to be actually used was placed in the main body part 45 and the back cover part 41, actually formed with the material to be used, and an experiment was performed in which a signal was emitted from a transmitting antenna installed at a prescribed position.

The results of this experiment show that: for gold, gold alloy, silver alloy, copper alloy, brass, aluminum alloy, zinc alloy, manganese alloy, cemented carbide (an alloy comprising tungsten carbide and titanium carbide), the gain is increased by 2-3 db compared to the gain for stainless steel, titanium alloy, tantalum carbide. Similar experiments have shown that, not only for an external part made of metal having good reception sensitivity but also for an external part made of metal having poor reception sensitivity, by providing a portion of metal having good reception sensitivity, the reception sensitivity of the antenna inside the external part can be improved.

Comparing the resistance values of the metals used in the experiments, it was found that the resistivity having a value of 7 micro ohm cm or less can maintain good receiving sensitivity. As a result, it has been found that if a non-magnetic material, gold alloy, silver alloy, copper alloy, brass, aluminum alloy, zinc alloy, manganese alloy, cemented carbide is used as all or a part of the metal exterior member, it is possible to achieve good reception sensitivity even with the metal exterior member.

Further, it has been confirmed that even for a metal exterior part of an electronic device composed of a metal having a high specific resistance (e.g., stainless steel, titanium alloy, tantalum carbide), a certain receiving sensitivity can be achieved if a part thereof is a part made of the above-mentioned nonmagnetic material.

In addition, as for the material of the main body member 45 and the back cover member 41, there are cases where: in order to achieve partial area coloring, a resin member is employed in the front frame or the like, or in the case of such a structure, even a resin garnish is mounted to the side wall of the main body member as the garnish, but it is obvious that the case of using metal in the basic structure falls within the scope of the metal exterior member of the present invention.

In the present invention, it is also desirable that the structure is: the inner surface of the metal skin component and the outer surface of the antenna are substantially parallel, or the inner surface of the back cover of the metal skin component and the outer surface of the antenna are substantially parallel.

In addition, it is preferable that the rear cover member of the metal exterior member has a secondary planar shape.

It is also preferable in the present invention that one end face of both ends of the antenna is substantially perpendicular to the inner surface of the back cover member 41 of the metal exterior member 31.

In the present invention, it may be desirable that at least one nonmagnetic member having a resistivity of 7.0 micro-ohm-cm is fixed to the inner surface of the metallic exterior member 31, and it may be further desirable that the nonmagnetic material is at least one of gold, silver, copper, brass, aluminum, zinc, manganese, or an alloy thereof.

Furthermore, it is preferred in the present invention that the antenna 32 is constituted by a core 38 and a coil 40 composed of a plurality of turns wound around the core 38, and a member is made of a non-magnetic material, so that the antenna 32 projects on this member at least along a plane containing the axis of the core 38 or a member to which the member projects.

Preferably, in the present invention, the antenna 32 is constituted by a core 38 and a coil 40 composed of a plurality of turns wound around the core 38, and one end portion of the antenna 32 or a part corresponding to the antenna or a part corresponding to the part is made of a non-magnetic material.

In addition to each of the above-described specific examples, it is necessary to provide antistatic measures, and in the present invention, it is also preferable to provide at least a part of the metal exterior member 31 with a conductive member.

As the electrostatic processing mechanism of the present invention, for example, it is contemplated that a suitable conductive member is provided on a part of the body member 45 or the back cover member 41 and is provided at a predetermined distance from the antenna 32, and further, it is also contemplated that a conductive method such as soldering, silver paste, conductive ring, or conductive resin, or crimping, etc. may be employed.

For example, in an electronic or radio controlled timepiece, the structure should be such that, in the case of pushing or pulling a part of the push button or the stub, there is mutual contact between suitable contact points, thus allowing electrostatic discharge, or it should be possible to insert a suitable conductive ring into the electronic or radio controlled timepiece.

Further, in the radio controlled timepiece, at least one position on the main body member or the front frame member may be welded, or silver paste may be added to at least one position between the main body member and the front frame member.

Next, another structure may be realized for the electronic device 30 of the present invention, which aims to make the resistance value of at least a part of the bonding member 39 different from that of another position, and the method used for this purpose is: at least a portion of the joining member 39 formed by joining at least two metal members of the metal exterior member 31 is made smaller in planar surface area than the remaining portion of the joining member.

This may also be achieved by making at least the part of the body part 45 and/or the back cover part 41 over which the coil 40 of the antenna 32 protrudes thinner in material thickness than the other part of the body part 45 and the back cover part 41.

In the course of research to achieve practical use of the present invention, the present inventors studied that, in the electronic device 30, the bonding pressure of the bonding member 39 formed between the plurality of metal members constituting the metal exterior member 31 having the plurality of metal members causes a change in the gain of the antenna 32.

Specifically, the present inventors have studied that in the case where the metal exterior part 31 is constituted by two or more metal parts, such metal parts are actually joined together at a prescribed position, usually a peripheral portion, by one or more methods, for example, by bringing them into contact with each other and welding them together with a predetermined pressure; a plurality of bolts are used to put them in place with a predetermined fastening force, and they are assembled with each other by a crimping method, i.e., first forming separate male and female threads, and then screwing them together and fixing them in a threaded manner using a predetermined fastening force. Or by using an internal thread method, a filler fixing method, a tenon engagement fixing method, a quick-connect method, a welding method, a brazing method, a grooved reverse taper connecting method, a solid diffusion bonding method, and the like.

The present inventors studied that, in the metal exterior part 31, a change in contact pressure of the joining surfaces of the plurality of metal parts will change the gain of the antenna 32.

That is, in the exterior metal member 31 in which the main body member 45 and the back cover member 41 are connected to each other in the electronic device, if the fastening torque of the back cover member 41 is changed, there is a change in the gain (decibel) of the antenna 32, as shown in fig. 23.

Specifically, it has been studied that when the tightening torque is changed from 0 to 6N · m, the stronger the tightening torque becomes, the more the antenna gain decreases, and the maximum gain decrease is 3 db.

In addition, when the tightening torque exceeds 6N · m, although no measurement is performed because no measuring device is actually available, as can be seen from fig. 23, in the metal exterior part 31, when the contact pressure between the main body part 45 and the back cover part 41 is made stronger, the antenna gain is lowered.

Therefore, it is predicted that, in the metal exterior member 31, in addition to the joining of the main body member 45 and the back cover member 41 using the screw method, the same effects as described above can be achieved using one or more of the above-described welding method, fixing method using a plurality of bolts, crimping method, filler clamping method described previously, tenon-and-mortise method, quick-joining method, welding method, brazing method, grooved reverse-taper joining method, solid-state diffusion joining method, and the like.

For this reason, the present inventors have completed the following experiments with the object of studying the cause of the above phenomenon.

First, as shown in fig. 33(a) and 33(B), the characteristic values of the antenna 32 are compared in the case where one Vdd contact spring R is used in the electronic device 30 and in the case where the contact with the back cover member 41 is interrupted by removing or bending the Vdd contact spring R.

The results of the experiment are shown in fig. 24.

In fig. 24, data measurement is performed for data before the change under the condition that the Vdd contact spring R is normally used, and data measurement is also performed for data after the change under the condition that the contact between the Vdd contact spring R and the back cover member is interrupted.

If the two data are compared and the characteristic values of the antenna 32, including the gain data, are observed at the same time, it can be seen that there is no substantial difference between the two data.

However, even if the back cover member 41 is fastened by removing the Vdd contact spring R, the influence of the Vdd contact spring R caused by the fastening force can be eliminated.

Then, as shown in fig. 34(a) and (B), the present inventors compared characteristic values of the antenna 32 in the case where the contact point between the core 42 and the back cover member 41 is removed and the influence of deformation caused by the fastening force of the core 42 to the back cover member 41 is eliminated.

Fig. 25 shows that, as shown in fig. 34(a), the contact point between the movement 42 and the back cover member 41 is held by the cushion member P, and data measurement is performed on data before change at the contact point. And data measurement is performed on the data after the change as shown in fig. 34(B), when the contact point between the movement 42 and the back cover member 41 is removed.

If the two data are compared and the characteristic values of the antenna 32, including the gain data, are observed at the same time, it can be seen that there is no substantial difference between the two.

However, even if the back cover member 41 is fastened by removing the cushion member P, the influence on the movement 42 due to the fastening force can be eliminated.

Further, as shown in fig. 26(a), the inventors have inserted a suitable insulator between the main body member 45 of the metal exterior member 31 and the back cover member 41, and have studied the influence generated when the range of pressure values caused by pressing the movement 42 against the back cover member 41 is reduced.

The results are shown in fig. 26 (B).

In fig. 26(B), data measurement is performed on data before the change under the condition where the insulator is not inserted, and data measurement is performed on data after the change under the condition where the insulator is inserted.

If these two data are compared, it is difficult to assume that the fastening force of the back cover member 41 deforms the movement 42 and reduces the gain of the antenna 32, because no increase in gain is seen even when the fastening force on the movement 42 is reduced.

In this case, the present inventors have repeatedly studied the experimental results of fig. 6 and 8.

The experiments of fig. 6 and 8 were performed using a screw tightening torque of 3N · m.

If there are some of the splice components left in the sector as shown in figure 8, then the fact that the gain of the antenna 32 is slightly reduced can be appreciated as described above.

The present inventors have also completed another experiment.

Specifically, in the structure of fig. 6, a metal exterior member 31 is used, and the structure of the metal exterior member 31 is such that the sector providing the gap 55 is set to have a central angle of 90 °, and the gain of the antenna 32 is measured while changing the fastening force of the back cover member 41.

The results are shown in FIG. 27.

In fig. 27, the curve of 90 ° is a curve representing the gain of the antenna obtained in this experiment, and the "current curve" represents a curve representing the gain of the antenna used in the metal exterior part 31 in which the gap 55 is not formed.

From these experimental results, it can be seen that the amount of attenuation of the antenna gain caused by the fastening torque of the back cover part 41 is greatly reduced for the structure of this experiment compared to the structure in the past.

From these results, it is conceivable that since the antenna gain can be improved by cutting the threaded portion around the antenna, by making the fastening torque of the back cover member high, magnetic coupling can be generated using the threaded portion around the antenna, thereby generating an eddy current that hinders the occurrence of a resonance phenomenon in the antenna, and thus reducing the antenna gain.

Therefore, in the present invention, since it is considered not preferable to set the joining force between the main body member 45 of the metal exterior member 31 and the back cover member 41 to be excessively large, a proper fastening torque or joining force is required depending on a particular joining method.

However, even though the tightening torque of all the samples used in this experiment was constant, this unstable torque varied after the waterproofing test.

For example, in the case where the tightening torque is set to 2N · m, the maximum loosening torque is 1.6N · m, the minimum loosening torque is 0.8N · m, and the average loosening torque is 1.1N · m after the waterproof test (30 samples are measured). For the case of setting the tightening torque to 3N · m, the maximum loosening torque was 3.5N · m, the minimum and stabilization torque was 1.7N · m, and the average loosening torque was 2.5N · m after the waterproof test (30 samples were measured).

Samples with a tightening torque of less than 0.1N · m fail the waterproof test, regardless of the value of the tightening torque.

As can be seen from the above, since it is difficult to measure the tightening torque larger than 6N · m, and also since it is unnecessary for the antenna gain to be larger than 6N · m, it can be considered that the loosening torque of 6N · m or less is acceptable.

As can be seen from the above, the loosening moment may be 0.1-6 N.m, preferably 0.2-3.5 N.m in practice.

Further, in the filler clamping method, the tenon-and-mortise clamping method, and the like, a force (hereinafter referred to as a peeling force) for detaching the main body member and the back cover member is 10^-4N m, there is no problem in the water repellency test.

However, since it is also difficult to measure a mutual peeling force of more than 6N · m, and since a mutual peeling force of more than 6N · m is also not required for antenna gain, the mutual peeling force may be 10^-4N·m-6N·m。

Therefore, an electronic device according to another embodiment of the present invention includes: at least one antenna, an information processing device for processing information captured by the antenna, and a metal exterior member in which the antenna and the information processing device are accommodated. Wherein the metal shell is configured to receive magnetic flux from outside the metal shell and through the metal shell, and to resonate. And, the metal exterior member includes a main body (sidewall) member and a back cover member, wherein the main body (sidewall) member and the back cover member are joined to each other, and a mutual peel force range between the main body (sidewall) member and the back cover member is: 10^-4N · m to 6.0N · m.

Further, another embodiment of the present invention is an electronic device including: at least one antenna, an information processing device for processing information captured by the antenna, and a metal exterior member in which the antenna and the information processing device are accommodated. Wherein the metal shell is configured to receive magnetic flux from outside the metal shell and through the metal shell, and to resonate. And, the metal exterior member includes a main body (side wall) member and a back cover member, wherein the main body (side wall) member and the back cover member are engaged with each other by a screw mechanism, and a mutual peeling force range between the main body (side wall) member and the back cover member is: 0.1N.m to 6.0 N.m, preferably 0.2 N.m to 3.5 N.m.

Next, the following experiment was conducted in order to confirm the difference in effect of the present invention, which is related to the difference in the joining part of the exterior metal part 31 of the electronic device.

Specifically, the body member 45 of the metal exterior member 31 was formed by the upper body member and the middle body member, and after the upper body member and the middle body member were press-fitted and filled, they were closed by the back cover member, and the fastening torque for joining them to the back cover member was 3N · m, whereby the sample A, B, C, F could be obtained; sample D, E was obtained by joining the upper body member and the middle body member by laser welding, closing the upper body member and the middle body member by the back cover member, and joining them to the back cover member with a fastening torque of 3N · m. In each sampling, the same antenna 32 is disposed at the same position as shown in fig. 28, and the characteristic curve of the antenna is measured.

The experimental results are shown in fig. 29.

As is clear from the comparative experiment result of fig. 29, the antenna gains of the sample D made of titanium and the sample E made of stainless steel were reduced.

The reason for the reduction in the antenna gain can be considered to be the strong magnetic coupling formed on the joining surface between the upper body section and the middle body section.

For this reason, in samples D and E, in the laser welding portion 39 formed on the joining surface between the upper body member and the middle body member as shown in fig. 28, a portion corresponding to the portion determined by the center angle of 90 ° in the sector 57 was removed to form the gap 55 to obtain the insulating function, and thus the same gain as that of the other samples was obtained.

The results of the experiment are shown in fig. 30.

Although the above example is an example in which the joint member between the upper body member and the middle body member is joined by welding, laser welding may be used in combination with the joining member between the body member and the back cover member in the present invention.

In this case, the inter-joint part between the body part and the back cover part as shown in fig. 4(a) may be used to form substantially the same shape as the annular joint part 39, the entire surface of the annular joint part 39 may be laser-welded, or, similarly to the above, among the annular joint part 39, it is expected that the part of the joint part 39 opposite to the antenna is left intact without laser-welding this part.

Next, specific examples related to still another embodiment of the present invention are described.

Specifically, this embodiment is a radio-controlled timepiece having: antenna, watch movement, dial, housing and back cover. The casing and the rear cover are made of metal, and the antenna is surrounded by the casing, the rear cover and the dial plate; an antenna is disposed in a space formed by the case, the back cover, and the dial together with the watch movement, the back cover, and the dial in the case, and disposed so that the antenna overlaps the dial in a planar manner, and wherein the dial is made of a non-magnetic material.

Furthermore, in this embodiment, between the dial and the movement there is a solar cell, which serves as the drive power source for the movement, this solar cell being substantially formed of a non-magnetic and magnetically permeable material.

In this embodiment, it may be desirable that this solar cell is formed of amorphous silicon as a main material.

A specific example of the radio controlled timepiece of the above embodiment of the invention is described below with reference to fig. 37 and 38.

Specifically, fig. 37 and 38 show a radio-controlled timepiece which is an embodiment of the above-described invention, fig. 37 is a sectional view showing mainly the constituent parts in outline, and fig. 38 is an overall plan view seen from the dial side.

In fig. 37 and 38, both the housing 503 and the rear cover 504 are formed of metal. In this way, it is possible to realize a radio-controlled timepiece as thin as a conventional wristwatch.

In this case, the antenna 501 is accommodated in a cylindrical closed space 507, said closed space 501 being formed by a metal housing 503, a back cover 504, which is also metal, a dial 505, and a solar cell 508. The solar cell 508 generates electric energy by light passing through the dial 505, and the solar cell 508 is disposed between the watch movement 502 and the antenna 501 and the dial 505.

In this structure, in the case where the back cover 504 of the case 503 is formed of metal, when the dial 505 is also formed of metal, since this structure is a structure in which the antenna 501 is accommodated in a closed space completely shielded by metal parts, the radio signal 509 reaching the antenna 501 is attenuated by these metal parts. Then, there is a problem that the reception sensitivity cannot be sufficiently achieved to be used as a final wristwatch.

Specifically, when a radio signal 509 impacts the antenna 501, a magnetic field may be generated in a region surrounding the antenna 501 and a current may be generated in the antenna coil 501b because the antenna core 501a may pass the radio signal. However, there is a problem that, in the case where a large metal part which easily passes a magnetic field is located in this region of the antenna 501, a part of the magnetic field generated around the antenna 501 as the center of this region is absorbed into this metal part, thereby causing a resonance phenomenon in the antenna 501 to be hindered, and a sufficient reception sensitivity cannot be achieved.

In this embodiment of the present invention, the dial 505 forming one surface of the closed space 507 accommodating the antenna 501, and the solar cell 508 sandwiched between the dial 505 and the movement 502 are formed of a nonmagnetic material which easily passes through a magnetic field, correspondingly to the above. Specifically, the dial 505 is formed of a high polymer resin that can pass light. Since the time is represented and the dial scale for decoration occupies only a very small proportion of the entire dial 505, even if it is metallic or plated, it has hardly any effect on reception. Of course, they are also preferably the same high polymer resins as the base material.

The solar cell 508 is formed of a non-magnetic material, typically amorphous silicon. An alternative frequently used is a film formed by depositing amorphous silicon, such as a high polymer resin or the like, onto a non-metallic sheet. In this way, since the material of the solar cell 508 is a non-metallic material that can pass a magnetic field, similarly to the dial 505, there is no influence on the radio signal 509 that is incident from the direction of the dial 505 and passes through the non-metallic glass 506.

Thus, as shown in fig. 37, the enclosed space 507 is a cylindrical space which accommodates the antenna in the form of a complete wristwatch in this embodiment, and since a magnetic space can be formed by opening one surface thereof to reduce the magnetic flux absorbed by nearby metal parts, the antenna 501 can be used to receive the radio signal 509.

Specifically, in this embodiment, the antenna is not placed in a completely magnetically shielded enclosure, and a part thereof is opened. In doing so, although the radio signal 509b incident from the direction of the metal case 503 and the back cover member 504 is attenuated, the radio signal 509a incident from the direction of the dial 505 can pass through the glass 506, the dial 505, and the solar cell 508, and can reach the antenna 501.

By adopting such a structure, the radio signal 509 can be received even when the housing 503 and the back cover member 504 are both made of metal.

As described above, in the radio-controlled timepiece of the invention, as for the radio-controlled wristwatch in which the case and the back cover are both made of a metal material, by opening the magnetic circuit of one side thereof, the radio-controlled wristwatch with a desired sensitivity can be realized; even for metal exterior parts.

Specifically, in a radio-controlled wristwatch using a metal case and a metal back cover, a magnetically permeable non-magnetic material is used for a dial and a solar cell laminated with the dial. In doing so, the resulting structure is one in which radio signals can reach the antenna housed in the closed space formed by the case and the back cover and the dial, so that the metal exterior member and the back cover can be used.

By doing so, it is possible to realize the whole thickness of the final timepiece to be thin, which is difficult in the prior art, and thus it is possible to realize a wide range of products.

It is also possible to realize a radio-controlled timepiece capable of utilizing the metal exterior member to the maximum extent with a high-quality tactile quality.

By utilizing metal exterior components, the present invention greatly increases efficiency and can be applied to watches such as divers' waterproof watches.

Further, with the above-described structure, the present invention solves the problems of the prior art described above, and can achieve excellent reception efficiency with a simple antenna structure, in which no large modification is required for the structure, metal exterior parts, design, or the like of the corresponding radio-controlled timepiece, and at the same time, no large thickness is required for the electronic device itself, so that the degree of freedom in design can be improved, and the manufacturing cost of the electronic device can be reduced.

Claims

1. An electronic device, comprising: an antenna, an information processing apparatus for processing information captured by the antenna, and a metal exterior member for accommodating the antenna and the information processing apparatus therein; wherein,

the metal appearance part comprises a metal shell and a metal rear cover;

the metal exterior part inserts a high elastic material between the main body part and the metal back cover and compresses the high elastic material between the main body and the metal back cover to increase sealability against water, and,

the antenna is in the vicinity of the information processing device, and is surrounded by the metal housing and the metal back cover;

a metal case and a metal back cover of at least a part of the metal exterior member, the metal case and the metal back cover having different resistance values from those of the metal case or the metal back cover, so that the antenna can receive magnetic flux from the outside of the metal exterior member and passing through the metal exterior member, and can resonate;

the antenna is disposed close to the engagement member.

2. The electronic device of claim 1, wherein, in the case where the electronic device is an electronic watch, the electronic watch further comprises: watch movement and dial;

the antenna and the watch movement are arranged in a space enclosed by the metal case, the metal back cover and the dial, so that the antenna overlaps the dial in a planar manner, and the dial is made of a non-magnetic material.

3. The electronic device according to claim 2, further comprising a solar cell formed of a nonmagnetic material that is easily permeable to a magnetic field between the dial and the watch movement, the solar cell serving as a driving power source of the watch movement.

4. The electronic device of claim 3, wherein: the solar cell is in the shape of a film using a non-metallic sheet.

5. The electronic device according to claim 1, wherein a part of the joining member having the resistance value different from that of the metal case or the metal back cover is an insertion member inserted in at least a part of the joining member.

6. The electronic device according to claim 5, wherein the insertion member is a film formed on at least one of the metal case and the metal back cover.

7. The electronic device according to claim 6, wherein the film is formed by appropriate surface treatment and/or hardening treatment of at least one of the metal housing and the metal back cover.

8. The electronic device of claim 7, wherein the film is formed by a method selected from the group consisting of: a wet plating method, a dry plating method, and a heat treatment.

9. The electronic device of any of claims 5-8, wherein the electrical resistance of the insert component is greater than the electrical resistance of a plurality of components forming the metal skin component.

10. The electronic device of claim 1, wherein: the bonding member having a part of the resistance value different from the resistance value of the metal case or the metal back cover is a gap formed at least in a part of the bonding member.

11. The electronic device of claim 10, wherein the gap is formed by removing a portion of the threads that engage the side wall member of the metal exterior member and the metal back cover.

12. The electronic device according to claim 5 or 10, wherein the insertion part or the gap of the metal exterior part is continuously or intermittently formed within the engagement part surrounded by a sector formed by both end portions of a magnetic core of the antenna and a central portion of the metal exterior part.

13. The electronic device of claim 1, wherein the antenna is provided with a gap between the antenna and an inner surface of the metal housing.