JP4983293B2 - Radio clock - Google Patents

Description

  The present invention relates to a radio-controlled timepiece with a built-in antenna.

2. Description of the Related Art Conventionally, in an electronic timepiece such as an electronic wristwatch, a radio timepiece that receives time information transmitted by a standard time radio wave with an antenna and corrects the time is known.
In such a radio timepiece, even if the watch case incorporating the antenna is made of metal, in order to ensure the reception performance of the standard time radio wave, as described in Patent Document 1, a metal back cover is used. There is a configuration in which a thin thin portion corresponding to an antenna is formed to reduce shielding of magnetic flux of standard time radio waves by a metal back cover.
JP 2004-347552 A

  However, in such a conventional radio-controlled timepiece, since the case back is made of metal, when the magnetic flux of the standard time radio wave is transmitted through the timepiece case, the magnetic flux transmitted through the lower side of the timepiece case located on the case back side. This is less than the upper side of the watch case located on the watch glass side, and therefore there is a problem that the antenna cannot receive radio waves efficiently, and the antenna receiving efficiency is insufficient.

  The problem to be solved by the present invention is to provide a radio-controlled timepiece that can sufficiently increase the efficiency of radio wave reception by an antenna.

In order to solve the above problems, the present invention includes the following components.
According to the first aspect of the present invention, there is provided a metal watch case having a watch glass attached to the upper portion and a metal back cover attached to the lower portion, and an antenna disposed in the watch case and having a coil wound around a core. In the radio clock with
In the watch case, at least the thin part with the thinnest upper part located on the watch glass side is formed,
The thin-walled portion corresponds to both ends of the core of the antenna, and an inner surface of the thin-walled portion is provided with a reinforcing member having insulating properties,
The antenna is a radio-controlled timepiece which is disposed in the watch case in a state where both end portions of the core are inserted into the reinforcing member .

  According to a second aspect of the present invention, in the radio timepiece according to the first aspect, the antenna has a configuration in which both end portions of the core are bent toward an upper side of the thin portion of the timepiece case. It is.

  According to the present invention, when the magnetic flux passes through the metal watch case, the magnetic flux passing through the upper part of the watch case located on the watch glass side and entering the watch case is Pay attention to the fact that there is more compared to the lower side of the watch case located at the top, and increase the magnetic flux transmitted through the upper side of the watch case by the thin-walled part where the upper part on the watch glass side is the thinnest. Can be made.

  For this reason, the magnetic flux transmitted through the watch case can be easily captured by the antenna, and even when the watch case and the back cover are made of metal, the reception efficiency of the radio wave by the antenna can be increased. Further, since the electrical resistance in the thin wall portion 12 of the watch case 1 is increased, when an induced current flows through the coil of the antenna, eddy current is prevented from being generated in the thin wall portion, and the induced current loss generated in the coil is reduced. This can also reduce the reception efficiency of radio waves by the antenna. For this reason, it is possible to sufficiently increase the receiving sensitivity of the antenna while maintaining the high-quality feeling by securing the metallic appearance of the entire watch.

(Embodiment 1)
A first embodiment in which the present invention is applied to an electronic wristwatch will be described below with reference to FIGS.
As shown in FIG. 1, the electronic wristwatch includes a wristwatch case 1. The wristwatch case 1 is formed of a metal such as titanium or stainless steel in a hollow shape that is hollow inside and opened up and down. A watch glass 2 is attached to the upper part of the watch case 1, and a metal back cover 3 is attached to the lower part of the watch case 1. A watch module 4 is provided inside the watch case 1.

  As shown in FIG. 1, the timepiece module 4 includes various electronic components necessary for a timepiece function such as a timepiece movement 5 and an antenna 6. In the timepiece movement 5, the pointer shaft 7 protrudes above the dial plate 8, and a pointer 9 such as an hour hand or a minute hand is attached to the tip of the protruding pointer shaft 7, and the pointer 9 moves above the dial plate 8. Thus, the time is indicated. In this case, the dial 8 is made of synthetic resin, and hour letters (not shown) are provided at equal intervals on the peripheral edge of the upper surface thereof, and the upper side in the watch case 1 in a state corresponding to the lower surface of the watch glass 2. Is provided.

  The antenna 6 is configured such that an induced current is generated in the coil 11 when the coil 11 is wound around the outer periphery of the core 10 having a high magnetic permeability and a magnetic flux is transmitted through the core 10. In this case, as shown in FIG. 1, the antenna 6 is arranged on the bottom side in the wristwatch case 1 located below the dial 8, and both ends 10a of the core 10 (only one side is shown in FIG. 1). Is configured to be bent obliquely upward toward the upper side in the watch case 1, that is, the outer peripheral side of the watch glass 2. Further, the antenna 6 is arranged at the 3 o'clock side or the 9 o'clock side in the wristwatch case 1. When the antenna 6 is arranged at the 3 o'clock side, both end portions 10a of the core 10 are located near 2 o'clock and 4 o'clock. When it is located in the vicinity and is arranged on the 9 o'clock side, both end portions 10a of the core 10 are located near 8 o'clock and 10 o'clock.

  By the way, as shown in FIG. 1, the wristwatch case 1 is formed with a thin portion 12 having the thinnest upper portion located on the watch glass 2 side. The thin portion 12 is such that the thickness on the upper side of the watch case 1 is the thinnest over the entire circumference of the watch case 1 and the thickness on the lower side of the watch case 1 is gradually increased over the entire circumference. It is formed by scraping the inner peripheral surface of the case 1 into a taper shape. A reinforcing member 13 is provided on the inner peripheral surface of the thin wall portion 12, and the watch glass 2 is attached to the upper portion of the reinforcing member 13.

  The reinforcing member 13 is made of a high-strength synthetic resin having insulating properties, and the thickness on the upper side is the thickest over the entire circumference of the watch case 1, and the thickness on the lower side of the watch case 1 is that of the watch case 1. It is provided on the inner peripheral surface of the thin-walled portion 12 so as to be gradually thinner over the entire circumference, and is thereby formed so as to fill a taper-shaped portion of the inner peripheral surface of the watch case 1. Thus, the reinforcing member 13 is configured to reinforce the thin portion 12 of the watch case 1 and ensure the strength of the entire watch case 1.

  In this case, the antenna 6 has the both ends 10 a of the core 10 corresponding to the thin part 12 formed in the watch case 1 and is bent toward the upper part of the thin part 12 in the watch case 1. It is arranged at 3 o'clock side or 9 o'clock side. A bezel 14 is attached to the upper outer periphery of the watch case 1, and the bezel 14 is made of synthetic resin having high insulation and high strength, like the reinforcing member 13. Configured to decorate.

  In such an electronic wristwatch, an insulating watch is provided when the magnetic flux of the standard time radio wave is transmitted through a metal watch case 1 having a watch glass 2 attached to the top and a metal back cover 3 attached to the bottom. The magnetic flux penetrating through the upper side of the watch case 1 located on the glass 2 side and entering the watch case 1 is larger than that on the lower side of the watch case 1 located on the metal back cover 3 side. 1 is formed with the thinnest portion 12 having the thinnest wall thickness on the watch glass 2 side, the magnetic flux passing through the upper side of the watch case 1 is increased, and this increased magnetic flux is transmitted to the core 10 of the antenna 6. This makes it easier to capture, thereby improving the reception performance of the antenna 6.

  That is, the watch case 1 is provided with the watch glass 2 on the upper portion thereof by the reinforcing member 13 and the metal case back 3 on the lower portion of the watch case 1 so that the standard time as shown in FIG. When the magnetic flux of radio waves passes through the watch case 1, the watch glass 2 is generally not a metal but has an insulating property, so that the watch case passes through the upper side of the watch case 1 located on the watch glass 2 side. The magnetic flux entering 1 is greater than that on the lower side of the watch case 1 located on the back cover 3 side made of metal. Further, since the thin portion 12 having the thinnest upper portion is formed on the metal watch case 1, the thin portion 12 increases the permeability of the upper portion of the watch case 1 so that the upper portion of the watch case 1 is More magnetic flux is transmitted.

  For example, when the wristwatch case 1 is made of titanium, the magnetic permeability gradually increases as the wall thickness decreases. In other words, the radio wave permeability depends on the skin depth of the metal, and the relationship between the thickness of titanium and the radio wave transmittance is as shown in FIG. 4 when the frequency of radio waves is 40 kHz and 60 kHz, As the thickness increases, the magnetic flux transmittance gradually decreases. When the transmittance is 0.37, the skin depths of the frequencies of 40 kHz and 60 kHz are about 1.87 mm and about 1.52 mm, respectively.

  Based on this, when the wristwatch case 1 is made of titanium and has a thickness of about 3 mm, the antenna 6 disposed in the wristwatch case 1 is simulated to receive radio waves. The results shown in FIGS. 2 and 3 were obtained. In this case, FIG. 2 is a case of the first embodiment in which the thin portion 12 is formed in the watch case 1, and FIG. 3 is a conventional example in which the thin portion 12 is not provided in the watch case 1. FIGS. 2 and 3 are diagrams of simulation results showing the magnetic field inside and outside the watch case 1 with magnetic field vectors when the antenna 6 is receiving a standard radio wave of 40 kHz.

  That is, in the case of the simulation result of Embodiment 1 shown in FIG. 2, the magnetic flux of the standard radio wave enters the watch case 1 almost horizontally because the skin depth of titanium in the standard radio wave of 40 kHz is about 1.87 mm. Thus, the magnetic flux transmitted substantially horizontally through the wristwatch case 1 and the magnetic flux transmitted through the upper part of the wristwatch case 1 is concentrated on the end portion 10a of the core 10 of the antenna 6 as it is. It can be seen that most of the magnetic flux that has passed through the lower part of the wire travels along the back cover 3 and is less likely to enter the watch case 1.

  Further, in the case of the simulation result of the conventional example shown in FIG. 3, since the skin depth of titanium in the standard radio wave of 40 kHz is about 1.87 mm, the magnetic flux of the standard radio wave enters the watch case 1 from obliquely below. After passing through the watch case 1 obliquely upward, the magnetic flux transmitted through the upper part of the watch case 1 proceeds obliquely upward and then toward the end 10a of the core 10 of the antenna 6. However, it can be seen that most of the magnetic flux transmitted through the lower part of the wristwatch case 1 travels along the back cover 3 and hardly enters the wristwatch case 1.

  Comparing the simulation results shown in FIGS. 2 and 3, in the case of the first embodiment shown in FIG. 2, the optimum state when the antenna 6 receives the standard radio wave is that the magnetic flux of the standard radio wave is the watch case 1. , And the magnetic flux that has passed through the upper part of the watch case 1 and entered the watch case 1 is almost concentrated on the end 10a of the core 10 of the antenna 6 as it is. On the other hand, in the case of the conventional example shown in FIG. 3, the optimum state when the antenna 6 receives the standard radio wave is that the magnetic flux of the standard radio wave transmits through the watch case 1 obliquely from below and the watch case 1 The magnetic flux that passes through the upper part and enters the watch case 1 travels obliquely upward of the watch case 1, then turns around obliquely downward, and concentrates on the end 10 a of the core 10 of the antenna 6.

  For this reason, the magnetic flux of the standard radio wave that passes through the watch case 1 and enters the watch case 1 is received by the antenna 6 in the case of the first embodiment provided with the thin portion 12 shown in FIG. Since the magnetic flux that passes through the watch case 1 almost horizontally is captured, the magnetic flux enters the watch case 1 more efficiently than the conventional example shown in FIG. 3 in which the thin portion 12 is not provided. It can be seen that the magnetic permeability of Embodiment 1 shown in FIG. 2 is higher than that of the conventional example shown in FIG.

  Thus, according to this electronic wristwatch, when the magnetic flux of the standard time radio wave is transmitted through the metal watch case 1 with the watch glass 2 attached to the upper part and the metal back cover 3 attached to the lower part, the insulation is achieved. The magnetic flux penetrating through the upper side of the watch case 1 located on the side of the watch glass 2 having the property and entering the watch case 1 is larger than that on the lower side of the watch case 1 located on the metal back cover 3 side. In addition, since the thin part 12 having the thinnest thickness on the watch glass 2 side is formed in the watch case 1, the magnetic flux transmitted through the upper part of the watch case 1 can be increased.

  For this reason, the magnetic flux that has passed through the upper side of the watch case 1 can be easily captured by the core 10 of the antenna 6 having a high magnetic permeability, and even if the watch case 1 and the back cover 3 are made of metal, the watch glass The reception efficiency of radio waves by the antenna 6 can be increased by the magnetic flux passing through the thin portion 12 of the watch case 1 located on the second side. In particular, when the electric resistance in the thin portion 12 of the watch case 1 is increased, when an induced current flows through the coil 11 of the antenna 6, the generation of an eddy current in the thin portion 12 is suppressed, and the induction generated in the coil 11 is suppressed. The loss of current can be reduced, and the radio wave reception efficiency of the antenna 6 can also be increased. For this reason, the reception sensitivity of the antenna 6 can be sufficiently increased while the watch as a whole maintains a metallic appearance and maintains a high-class feeling.

  Further, in this electronic wristwatch, the antenna 6 has a configuration in which both end portions 10a of the core 10 are bent obliquely upward toward the upper portion of the thin portion 12 formed in the wristwatch case 1, so that the upper side of the wristwatch case 1 is transmitted. Thus, the magnetic flux of the radio wave can be efficiently concentrated on both end portions 10a of the core 10 of the antenna 6, whereby the radio wave reception efficiency of the antenna 6 can be further increased and the reception sensitivity of the antenna 6 is improved. be able to.

  Furthermore, in this electronic wristwatch, since the thin-walled portion 12 formed in the watchcase 1 is provided with a high-strength reinforcing member 13 having insulation properties, the thin-walled thin-walled portion 12 is formed in the watchcase 1. In addition, the thin portion 12 of the watch case 1 can be firmly reinforced without hindering the transmission of magnetic flux by the reinforcing member 12, and thereby the strength of the watch case 1 can be sufficiently secured.

(Embodiment 2)
Next, a second embodiment of an electronic wristwatch to which the present invention is applied will be described with reference to FIG. In addition, the same code | symbol is attached | subjected and demonstrated to the same part as Embodiment 1 shown by FIGS. 1-4.
This electronic wristwatch has a configuration different from that of the first embodiment in the configuration of the antenna 20, and has substantially the same configuration as that of the first embodiment except for this. In other words, as shown in FIG. 5, the antenna 20 has a configuration in which a core portion 21 is formed by superimposing first and second cores 22 and 23, and a coil 11 is wound around the core portion 21 to form an embodiment. 1, when a magnetic flux of radio waves passes through the core portion 21, an induced current is generated in the coil 11.

  In this case, as shown in FIG. 5, the first core 22 positioned on the upper side of the core portion 21 is an upper portion of the thin portion 12 in which both end portions 22 a (only one side is shown in FIG. 5) is formed in the watch case 1. The bent end portions 22a are bent obliquely upward toward the side, and are configured to approach the upper side of the reinforcing member 13 in the thin-walled portion 12 of the watch case 1. Further, the second core 23 positioned on the lower side of the core portion 21 has both end portions 23a (only one side is shown in FIG. 5) extending substantially horizontally toward the inner surface of the wristwatch case 1, and this extension. Both end portions 23 a are configured to approach the lower side of the reinforcing member 13 in the thin-walled portion 12 of the watch case 1.

  Such an electronic wristwatch also has the same effects as those of the first embodiment, and in particular, the core portion 21 of the antenna 20 has a configuration in which the first and second cores 22 and 23 are vertically stacked, and the first core. Both end portions 22a of 22 are bent obliquely upward toward the upper side of the thin portion 12 formed in the watch case 1, and both end portions 23a of the second core 23 extend substantially horizontally toward the inner surface of the watch case 1. Therefore, the magnetic flux of the radio wave transmitted through the upper part of the wristwatch case 1 is efficiently used by the amount that the both end portions 22a and 23a of the first and second cores 22 and 23 are opened at a predetermined angle. Therefore, the reception efficiency of the radio wave by the antenna 20 can be further enhanced as compared with the first embodiment.

  In this case, the antenna 20 has a watch case in a state in which both end portions 22a of the first core 22 located above the core portion 21 are close to the upper side of the reinforcing member 13 provided on the thin portion 12 of the watch case 1. 1, the magnetic flux of the radio wave transmitted through the upper side of the watch case 1 can be efficiently captured by the both end portions 22a of the first core 22 in the core portion 21 of the antenna 20, and this also allows the antenna 20 to Can improve the reception efficiency of radio waves.

(Embodiment 3)
Next, a third embodiment of an electronic wristwatch to which the present invention is applied will be described with reference to FIG. Also in this case, the same portions as those in the first embodiment shown in FIGS.
This electronic wristwatch has a configuration in which both end portions 31a (only one side is shown in FIG. 6) of the core 31 of the antenna 30 are inserted into the reinforcing member 13 provided on the thin-walled portion 12 of the wristwatch case 1. The configuration is almost the same as in the first embodiment.

  That is, as in the first embodiment, the antenna 30 is configured such that an induced current is generated in the coil 11 when the coil 11 is wound around the outer periphery of the core 31 having high magnetic permeability and the magnetic flux of the radio wave is transmitted through the core 31. Yes. In this case, as shown in FIG. 6, the antenna 30 is disposed on the bottom side in the wristwatch case 1 located below the dial 8, and both end portions 31 a of the core 31 (only one side is shown in FIG. 6). Is folded obliquely upward toward the reinforcing member 13 provided on the thin-walled portion 12 of the wristwatch case 1, and both the bent end portions 31a are inserted into the reinforcing member 13 while being bitten into the reinforcing member 13 obliquely from below. Arranged in the case 1.

  According to such an electronic wristwatch, the same effects as in the first embodiment are obtained, and both end portions 31a of the core 31 of the antenna 30 are obliquely attached to the reinforcing member 13 provided on the thin portion 12 of the wristwatch case 1 from below. Since the antenna 30 is arranged in the wristwatch case 1 in a state where it is inserted, the magnetic flux of the radio wave transmitted through the upper part of the wristwatch case 1 is more efficiently used than in the first embodiment, and the core 31 of the antenna 30 is used. Thus, the reception efficiency of the radio wave by the antenna 30 can be further enhanced.

  In the third embodiment, the case where both end portions 31a of the core 31 of the antenna 30 are inserted into the reinforcing member 13 provided on the thin portion 12 of the wristwatch case 1 from obliquely below has been described. For example, as in the modification shown in FIG. 7, both end portions 33a (only one side is shown in FIG. 7) of the core 33 of the antenna 30 are directed toward the upper portion of the reinforcing member 13 provided in the thin portion 12 of the watch case 1. A configuration may be adopted in which the bent end portions 33a are bent and inserted into the upper portion of the reinforcing member 13 at a substantially right angle.

  With this configuration, even if both end portions 33a of the core 33 of the antenna 30 are inserted into the reinforcing member 13, as shown in FIG. 7, the respective tip portions of the end portions 33a of the core 31 (only one side in FIG. 7). Can be sufficiently separated from the metal portion of the thin portion 12 of the wristwatch case 1 as compared with the third embodiment, so that when an induced current flows through the coil 11 of the antenna 30, the eddy current flows in the thin portion 12. Can be suppressed and the loss of the induced current generated in the coil 11 can be reduced, so that the reception efficiency of the radio wave by the antenna 30 can be improved as compared with the third embodiment.

(Embodiment 4)
Next, a fourth embodiment of an electronic wristwatch to which the present invention is applied will be described with reference to FIG. Also in this case, the same portions as those in the first embodiment shown in FIGS.
This electronic wristwatch has a configuration in which the thin-walled portion 40 is formed in the wristwatch case 1 in a shape different from that of the first embodiment, and the other configuration is substantially the same as that of the first embodiment.

  That is, as shown in FIG. 8, the thin wall portion 40 has the thinnest wall thickness on the watch glass 2 side of the watch case 1 over the entire circumference, and the wall thickness on the lower side of the watch case 1 on the entire circumference. The inner peripheral surface of the wristwatch case 1 is formed in a stepped shape so as to become gradually thicker. Also in this case, the reinforcing member 13 made of high-strength synthetic resin having insulation is provided on the inner peripheral surface of the thin portion 40.

  The reinforcing member 13 has a thickness on the upper side that is the thickest over the entire circumference of the watch case 1 and a thickness on the lower side of the watch case 1 that gradually decreases over the entire circumference. It is provided on the inner peripheral surface, and is configured so as to fill a stepped portion on the inner peripheral surface of the wristwatch case 1. In the antenna 6, as in the first embodiment, both end portions 10 a of the core 10 are bent toward the top of the thin portion 40 of the watch case 1, and the bent both end portions 10 a are close to the reinforcing member 13. The watch case 1 is arranged.

  Also in such an electronic wristwatch, a staircase is formed on the inner peripheral surface of the watch case 1 so that the thickness of the upper part of the watch case 1 on the watch glass 2 side is the thinnest and the thickness of the lower part of the watch case 1 is gradually increased. Since the thin-walled portion 40 is provided on the wristwatch case 1 and the reinforcing member 13 is provided on the inner peripheral surface of the thin-walled portion 40, the same effects as those of the first embodiment are obtained.

(Embodiment 5)
Next, a fifth embodiment of an electronic wrist watch to which the present invention is applied will be described with reference to FIG. Also in this case, the same portions as those in the first embodiment shown in FIGS.
This electronic wristwatch has a configuration in which the thin-walled portion 41 is formed in the wristwatch case 1 in a shape different from that of the first embodiment, and the other configuration is substantially the same as that of the first embodiment.

  That is, as shown in FIG. 9, the thin wall portion 41 is formed so that the thickness of the upper side of the watch case 1 is the thinnest in a substantially cylindrical shape, and the thickness of the lower side of the watch case 1 is moderate over the entire circumference. The wristwatch case 1 is formed in a shape obtained by shaving the inner peripheral surface of the wristwatch case 1 so as to bend and gradually become thicker. Also in this case, the reinforcing member 13 made of high-strength synthetic resin having insulation is provided on the inner peripheral surface of the thin portion 41.

  The reinforcing member 13 is thickest in a substantially cylindrical shape on the upper side thereof, and the thickness of the lower portion side of the watch case 1 is gently curved over the entire circumference so as to gradually become thinner. It is provided on the inner peripheral surface, and is configured to fill a portion of the shape obtained by scraping the inner peripheral surface of the watch case 1. In the antenna 6, as in the first embodiment, both end portions 10 a of the core 10 are bent toward the upper portion of the thin portion 41 of the watch case 1, and the bent both end portions 10 a are close to the reinforcing member 13. The watch case 1 is arranged.

  Such an electronic wrist watch has the same effects as those of the first embodiment, and the upper thickness of the wrist watch case 1 is formed in a substantially cylindrical shape, and the lower thickness of the wrist watch case 1 is gradually reduced. Since the thin-walled portion 41 is provided in the watch case 1 by scraping the inner peripheral surface of the watch case 1 so as to bend and gradually thicken, the magnetic flux passing through the upper side of the watch case 1 is further increased than in the first embodiment. Thus, the receiving efficiency of the antenna 6 can be further increased.

(Embodiment 6)
Next, with reference to FIG. 10, Embodiment 6 of the electronic wristwatch to which the present invention is applied will be described. Also in this case, the same portions as those in the first embodiment shown in FIGS.
This electronic wristwatch has a configuration in which the thin-walled portion 42 is formed in the wristwatch case 1 in a shape different from that of the first embodiment, and the other configuration is substantially the same as that of the first embodiment.

  That is, as shown in FIG. 9, the thin-walled portion 42 has a thickness substantially reduced to a cylindrical shape from the upper part on the watch glass 2 side to the lower part on the back cover 3 side in the watch case 1. Is formed in a shape obtained by scraping the inner circumferential surface into a substantially cylindrical shape. Also in this case, the reinforcing member 13 made of high-strength synthetic resin having insulation is provided on the inner peripheral surface of the thin portion 42.

  The reinforcing member 13 is formed in a substantially cylindrical shape on the inner peripheral surface of the watch case 1 so that the thickness increases from the upper part on the watch glass 2 side to the lower part on the back cover 3 side in the watch case 1. It is configured to fill the shaved part. In the antenna 6, as in the first embodiment, both end portions 10 a of the core 10 are bent toward the upper portion of the thin portion 42 of the watch case 1, and the bent both end portions 10 a are close to the reinforcing member 13. The watch case 1 is arranged.

  Such an electronic wristwatch also has the same effects as those of the first embodiment, and the thickness of the wristwatch case 1 is reduced to a substantially cylindrical shape from the upper portion on the watch glass 2 side to the lower portion on the back cover 3 side. In addition, since the inner peripheral surface of the watch case 1 is scraped off into a substantially cylindrical shape, the thin portion 42 having the same thickness is provided from the top to the bottom of the watch case 1. The magnetic flux passing through the case 1 can be further increased, and thereby the receiving efficiency of the antenna 6 can be further increased.

  In the above-described fourth to sixth embodiments, the case where the antenna 6 in which the coil 11 is wound around the core 10 is used has been described. However, the present invention is not limited to this. For example, as in the second embodiment illustrated in FIG. The antenna 20 in which the coil 11 is wound around the core portion 21 in which the second cores 22 and 23 are overlapped may be used. Further, as in the third embodiment shown in FIG. 6 and the modification shown in FIG. The antenna 30 may be disposed in the watch case 1 with both end portions 31 a and 33 a of the cores 31 and 33 being inserted into the reinforcing member 13.

  Moreover, although the said Embodiments 1-6 described the case where the thin part 12, 40-42 was provided over the perimeter in the inner peripheral surface of the wristwatch case 1, it is not restricted to this, For example, antenna 6, 20, The thin-walled portions 12 and 40 are provided only at locations corresponding to the both end portions 10a, 31a and 33a (or 22a and 23a) of the 30 cores 10, 31, and 33 (or the first and second cores 22 and 23 of the core portion 21). The structure provided with -42 may be sufficient. For example, when the antennas 6, 20, and 30 are arranged on the 3 o'clock side, they may be provided near 2 o'clock and around 4 o'clock, and the antennas 6, 20, and 30 are arranged on the 9 o'clock side. In such a case, it may be provided around 8 o'clock and 10 o'clock. Even if comprised in this way, there exists an effect similar to Embodiment 1-6.

  Furthermore, in the first to sixth embodiments and the modifications thereof, the case where the present invention is applied to an electronic wristwatch has been described. Can do.

It is an expanded sectional view of the important section showing Embodiment 1 of the electronic wrist watch to which this invention is applied. It is the figure of the simulation which showed the mode of the magnetic field when the antenna is receiving the electromagnetic wave in the wristwatch case of FIG. 1 by the magnetic field vector. It is the figure of the simulation which showed the mode of the magnetic field when the antenna was receiving the electromagnetic wave in the wristwatch case of the prior art example in which the thin part was not provided in the wristwatch case. It is the figure which showed the relationship between the thickness in titanium used for the wristwatch case of FIG. 1, and the transmittance | permeability of an electromagnetic wave. It is the expanded sectional view of the principal part which showed Embodiment 2 of the electronic wristwatch to which this invention is applied. It is the expanded sectional view of the principal part which showed Embodiment 3 of the electronic wristwatch to which this invention is applied. It is an expanded sectional view of the principal part which showed the modification of Embodiment 3 of this invention. It is sectional drawing of Embodiment 4 which showed the electronic wristwatch to which this invention was applied roughly. It is sectional drawing of Embodiment 5 which showed the electronic wristwatch to which this invention was applied roughly. It is sectional drawing of Embodiment 6 which showed the electronic wristwatch to which this invention was applied roughly.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Watch case 2 Watch glass 3 Back cover 4 Watch module 5 Watch movement 6, 20, 30 Antenna 8 Dial 10, 31, 33 Core 10a, 31a, 33a Core both ends 11 Coil 12 Thin part 13 Reinforcement member 21 Core part 22 1st core 22a Both ends of 1st core 23 2nd core 23a Both ends of 2nd core 40-42 Thin part

Claims (2)

In a radio-controlled timepiece comprising a metal watch case with a watch glass attached to the top and a metal back cover attached to the bottom, and an antenna that is placed in the watch case and has a coil wound around a core,
In the watch case, at least the thin part with the thinnest upper part located on the watch glass side is formed,
The thin-walled portion corresponds to both ends of the core of the antenna, and an inner surface of the thin-walled portion is provided with a reinforcing member having insulating properties,
The radio wave timepiece characterized in that the antenna is disposed in the timepiece case with both end portions of the core being inserted into the reinforcing member .   2. The radio timepiece according to claim 1, wherein both ends of the core of the antenna are bent toward an upper side of the thin portion of the watch case.

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