JP3797338B2 - Wristwatch with wireless function - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a wristwatch with a wireless function.
[0002]
[Prior art]
Conventionally, a wristwatch with a wireless function in which an antenna is built in a case has been sold. In this wristwatch, a non-conductive material such as plastic is generally used as a case material so that radio waves can reach the antenna without being shielded by the case. However, the non-conductive part material such as plastic has a problem that the luxury feeling of the wristwatch is impaired because the texture is not high-quality compared to the conductive part material such as stainless steel, brass or titanium. Therefore, in recent years, a configuration has been proposed in which a metal material is used at least on the side of the case, and the antenna is arranged at a position moved toward the center of the case so as to be arranged away from the case side (for example, Patent Document 1). reference).
[0003]
[Patent Document 1]
JP 2001-33571 (FIG. 1)
[0004]
[Problems to be solved by the invention]
However, the arrangement of the components of the movement housed in the case has already been optimized, and it is physically difficult to arrange the antenna at a position close to the center of the case. Therefore, in order to separate the antenna and the case, it is necessary to increase the diameter of the case, which not only increases the size of the wristwatch but also deteriorates the wearability and portability. .
[0005]
The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a wristwatch with a wireless function that can prevent deterioration of reception sensitivity of a built-in antenna without increasing the case diameter of the timepiece.
[0006]
[Means for Solving the Problems]
In order to achieve the above-described object, the present invention provides a back cover made of at least a part of a conductive member, a movement that is disposed on the back cover and realizes a timekeeping function, and the back cover and the movement from above. A case made of a conductive member covering; and a bar antenna housed in the case together with the movement and receiving radio waves from the outside, and both end faces of the bar antenna disposed in the case A recess is provided on the inner surface opposite to the end surface of the bar antenna. There is provided a wristwatch with a wireless function, characterized in that a space is provided between an inner surface of the case.
[0007]
According to the wireless function wristwatch of this configuration, the bar antenna is disposed in a space formed by cutting the inner surface of the case with a gap between the end surface and the inner surface of the space. It is possible to provide a gap between the bar antenna and the inner side surface of the case without increasing the size. Thereby, deterioration of the reception sensitivity of the bar antenna can be prevented.
[0008]
here, Said From the end face of the bar antenna Recess It is desirable that the separation distance to the inner surface satisfies a relationship of separation distance> L / S (S: coil cross-sectional area of the bar antenna, L: core length of the bar antenna). By providing a separation distance that satisfies this relationship, the reception sensitivity of the bar antenna can be made sufficient.
[0009]
Further, the non-conductive member of the back cover is formed by cutting at least the inner surface of the case. Said A configuration located below the recess is also desirable. With this configuration, radio waves easily pass through the non-conductive member of the back cover in the space where the bar antenna is arranged.
The back cover may be configured to include a frame material made of a metal material and a glass material fitted to the frame material, or may be formed from a ceramic material.
[0010]
Furthermore, the structure provided with the fixing member which consists of a nonelectroconductive material which fixes the bar antenna arrange | positioned in the said space may be sufficient.
Moreover, the structure provided with the inner frame which consists of a nonelectroconductive material for fixing the said movement to the said case may be sufficient.
Further, it is desirable that a dial for visually recognizing time is further provided, and the dial is made of a nonconductive member.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each of the following embodiments, as a wristwatch with a wireless function, a long wave standard radio wave (Japan JJY: 40 kHz / 60 kHz, US WWVB: 60 kHz, German DCF77: 77.5 kHz) is received, and a radio wave that corrects the time based on the received signal. An example of a modified wristwatch will be described.
[0012]
<First Embodiment>
FIG. 1 is an exploded perspective view showing a configuration of a radio wave correction wristwatch 1 according to the present embodiment, FIG. 2 is a view showing a configuration of the radio wave correction wristwatch 1, (a) is a cross-sectional view, and (b) is a cross-sectional view. It is a bottom view in the state where back pig 14 was removed. FIG. 1 shows the radio-controlled wristwatch 1 with the back side facing upward.
[0013]
As shown in FIG. 1 and FIG. 2A, the radio-controlled wristwatch 1 includes a movement (clock module) 16 that realizes a timekeeping function and a metal (for example, stainless steel or titanium) that is a conductive member. A case (also referred to as a “body”) 12, a back cover 14 that is partly made of a non-conductive member and fitted in an opening formed on the bottom surface of the case 12, and a transparent non-conductive member such as glass A cover glass 11 covering the upper surface of the case 12. Furthermore, the radio wave correction wristwatch 1 includes a dial 15 for displaying time and an antenna 17 for receiving a long wave standard radio wave. The dial 15 is disposed between the movement 16 and the cover glass 11. The antenna 17 is housed in the case 12 together with the movement 16.
[0014]
As shown in FIG. 3, the antenna 17 includes a lead wire 91 such as a copper wire around a core (bar) 171 made of an amorphous material obtained by laminating several tens of metal foils or a ferromagnetic material such as ferrite. Is a bar antenna formed by winding a coil in a coil shape. The antenna 17 has directivity that reacts to a magnetic field in a linear direction connecting the both end faces 17a and 17b of the core, and a long wave standard radio wave that penetrates each of the both end faces 17a and 17b of the core 171 (in detail, An induced electromotive force (induced electromotive voltage) is generated in the coiled lead wire 91 due to electromagnetic induction in accordance with the time variation of the magnetic field component of the long wave standard radio wave. And the fluctuation | variation of the electric potential of the both ends of a coil by an induced electromotive force is detected as a received signal.
[0015]
Here, although the antenna 17 is housed in the metal case 12 together with the movement 16, when the antenna 17 is disposed, the both end surfaces 17a and 17b are brought close to the inner wall of the case 12 so that both end surfaces of the antenna 17 are provided. Magnetic flux to be concentrated on 17a and 17b is attracted to the case 12, and the receiving sensitivity of the antenna 17 is deteriorated. Therefore, the antenna 17 needs to be arranged away from both end faces 17a and 17b. However, since the movement 16 is arranged at the center of the case 12, the arrangement position of the antenna 17 is set at the center of the case 12. In the end, it is necessary to increase the diameter of the case 12, which increases the watch size.
[0016]
Therefore, in the present embodiment, the antenna 17 is arranged as follows. Specifically, as shown in FIGS. 1 and 2B, a general case 12 has a band attaching portion (also referred to as “kan”) to which a watch band 18 wound around a user's wrist is attached. 121) is integrally molded. Therefore, in this embodiment, a portion of the side wall of the case 12 where the band mounting portion 121 is formed and thickened is cut away, and a wide gap is generated between the inner surface of the case 12 even if the antenna 17 is disposed. A space 122 is formed, and the antenna 17 is disposed in the space 122. As described above, since the antenna 17 is disposed in the space formed by cutting the thick portion of the side wall of the case 12, a gap is provided between the both end surfaces 17 a and 17 b and the inner surface of the space 122. Sensitivity deterioration can be prevented. Further, since the distance between the antenna 17 and the inner surface of the case 12 can be separated only around the antenna 17, the dimensions (outer shape) of the case 12 remain the same as those of the conventional case to ensure the antenna characteristics. It is possible to prevent the case 12 from becoming large because the antenna 17 is disposed. Furthermore, since the portion of the band attachment portion 121 of the case 12 is originally thick, even if the space 122 is formed, the case strength is hardly affected.
[0017]
Here, the dimension of the space 122 formed as described above is determined as follows. Specifically, in addition to being large enough to accommodate the antenna 17, when the antenna 17 is disposed, the separation distance from the both end surfaces 17a, 17b of the antenna 17 to the inner wall of the case 12 is small. , At least satisfying the relationship of separation distance> L / S. More specifically, the voltage V induced in the loop antenna using the magnetic core is V = Q (2πf / Δf) μnSH cos α (where Q: constant, Δf: 3 dB bandwidth, μ: effective permeability, n : The number of coil turns, S, coil cross-sectional area, H: magnetic field strength, α: angle between the magnetic field direction and the coil axis), and the more the magnetic field passes through the coil cross-sectional area S, that is, the coil cross-sectional area S increases. The better reception characteristics are obtained. In addition, the antenna directivity becomes sharper as the coil cross-sectional area S is smaller and the core 171 is longer (see FIG. 12A). Since the antenna characteristic becomes broader as the core 171 becomes shorter and the core 171 is shorter (see FIG. 12B), the magnetic field other than the antenna core axial direction is easily picked up, and the separation distance can be reduced. Therefore, the separation distance may be about separation distance> L / S (for example, core length L: 15 mm, coil cross-sectional area S: 4 mm). ² If the separation distance is maintained so as to satisfy this relationship, the reception sensitivity of the antenna 17 can be prevented from deteriorating. The space 122 may be formed by cutting after the case 12 is molded, or may be processed by metal injection molding (MIM).
[0018]
Next, the configuration of the radio wave correction wristwatch 1 according to the present embodiment will be described in detail. As shown in FIG. 1, a circular opening is formed in the center of the case 12, and a cover glass 11, which is a disk-shaped transparent glass, is fitted into the opening, as shown in FIG. The cover glass 11, the case 12, and the back cover 14 constitute a casing of the radio wave correction wristwatch 1. Note that the cross-sectional view of FIG. 2A does not show a cross section cut across the antenna 17 and the button 28. A band attaching portion 121 is integrally formed on the case 12, and the watch band 18 is attached to the band attaching portion 121 by a spring bar 181. The watch band 18 and the spring bar 181 are made of a metal material that is a conductive member such as stainless steel, brass, or titanium. As shown in FIGS. 1 and 2B, the case 12 is provided with a button 28 (operator) made of a metal material in the 3 o'clock direction of the timepiece. As described above, the watch band 18, the spring bar 181 and the button 28 are made of metal like the case 12, so that the appearance can be unified and a high-class feeling can be obtained. The number and arrangement position of the buttons 28 are arbitrary.
[0019]
As shown in FIG. 2 (a), the dial 15, the movement 16 and the antenna 17 are accommodated in the above-described casing composed of the case 12 and the back cover 14. The dial plate 15 is a flat plate member, and as shown in FIG. 2A, is fixed substantially horizontally with respect to the back lid 14 at the lower part of the cover glass 11 in the figure, and the lower part of the dial plate 15 in the figure. The movement 16 and the antenna 17 are arranged, and the entire lower surface thereof is covered with the back cover 14. The dial plate 15 is made of a non-conductive member such as a paper material or a plastic material. Further, the back cover 14 includes an outer frame 141 formed in a shape in which a metal material such as stainless steel, brass, or titanium is fitted into an opening formed below the case 12, and a glass material that is fitted into the outer frame 141. And a glass plate 142 made of a non-conductive member such as the like, and is fitted (or screwed) and fixed below the case 12.
[0020]
In this configuration, since the dial 15 is a non-conductive member as described above, radio waves pass through the cover glass 11 and the dial 15 from the upper surface of the radio-controlled wristwatch 1 (above FIG. 2A). Thus, it becomes easy to reach the inside of the housing. Similarly, since the glass plate 142 of the back cover 14 is a non-conductive member, it is easy for radio waves to reach the inside of the casing from the lower surface of the radio wave correction wristwatch 1 (below FIG. 2A). Thereby, since it becomes easy for a radio wave to reach the inside of the housing from the vertical direction of the radio-controlled wristwatch 1, the reception characteristics of the antenna 17 can be improved. Further, as shown in FIG. 1, the glass plate 142 of the back cover 14 is formed to have a size that is positioned below the space 122 formed in the case 12, whereby the antenna 17 is arranged. It is easy for radio waves to reach the space 122. The glass plate 142 is subjected to surface processing such as plating so that the inside of the housing is invisible and has a texture similar to that of a metal material, so that the portion that can be seen by the user (ie, the case 12 and the back cover). 14, the texture of the watch band 18, the spring bar 181 and the button 28) is unified with metal, thereby improving the sense of quality. Here, the area of the glass plate 142 of the back cover 14 is preferably as large as possible, and thereby the reception characteristics of the antenna 17 can be improved.
[0021]
Here, in order to prevent the reception characteristics of the antenna 17 from deteriorating, it is desirable that the antenna 17 be arranged apart from the movement 16 containing a large amount of metal material. However, in a wristwatch, the size of the housing (case 12) is limited. Therefore, in the present embodiment, as shown in FIG. 1, the movement 16 including the hand movement mechanism and the antenna 17 are arranged in parallel in the horizontal direction so as not to overlap each other, thereby reducing the thickness of the housing. By arranging the antenna 17 in the space 122 formed by cutting the band attaching portion 121, the antenna 17 is separated as much as possible from the movement 16 to prevent the reception characteristics of the antenna 17 from deteriorating.
[0022]
Next, a hand movement mechanism that is one component of the movement 16 will be described with reference to FIG. The hand movement mechanism is a mechanism that drives each of the second hand 71, the minute hand 72, and the hour hand 73, and is configured such that the second wheel 74, the second wheel 75, and the hour wheel 76 are interlocked with each other, as shown in FIG. Have a train wheel. One end of a second hand 71 is attached to the rotating shaft of the second wheel 74, and one end of a minute hand 72 is attached to the rotating shaft of the second wheel 75. Furthermore, one end of the hour hand 73 is attached to the rotation shaft of the hour wheel 76. The second wheel 74 is rotationally driven by a second motor 25 described later, and this rotation is transmitted to the second wheel 75 and the hour wheel 76, whereby each of the second hand 71, the minute hand 72, and the hour hand 73 is driven to set the time. Point to.
[0023]
On the surface of the second wheel 74, a magnetic material magnetized with a specific magnetic information pattern is attached along a circular orbit centering on the rotation axis of the second wheel 74. Further, in order to obtain the position (rotation angle) of the second hand 71, a second hand detection element 741 for reading the magnetic information pattern is fixed so that the magnetic body on the surface of the second wheel 74 faces the detection surface. Similarly, a magnetic body is affixed to the second wheel 75 and the hour wheel 76, and a minute hand detecting element 751 is fixed so as to face the magnetic body affixed to the second wheel 75, and is attached to the hour wheel 76. An hour hand detecting element 761 is fixed so as to face the magnetic body. Each of the second hand detection element 741, the minute hand detection element 751 and the hour hand detection element 761 outputs a detection signal corresponding to the read magnetic information pattern to an IC chip (not shown) of the movement 16. The IC chip includes a circuit for obtaining current pointer positions of the second hand 71, the minute hand 72, and the hour hand 73 based on detection signals from the second hand detecting element 741, the minute hand detecting element 751, and the hour hand detecting element 761, respectively, And a circuit for performing various processes such as drive control of the mechanism and time correction based on the long wave standard radio wave.
[0024]
FIG. 5 is a block diagram showing an electrical configuration of the movement 16. In this figure, an oscillation unit 21, a reception processing unit 22, a control unit 23, and a drive unit 24 are circuits formed on the above-described IC chip. The oscillation unit 21 includes an oscillation circuit (not shown) and a synthesis circuit (not shown). A crystal resonator 211 is connected to the oscillation circuit as a reference oscillation source. The oscillation circuit generates a reference pulse having a predetermined frequency and outputs it to the synthesis circuit. The synthesis circuit divides the reference pulse to generate a divided pulse, and synthesizes the divided pulse and the reference pulse to generate pulse signals having different pulse widths and edge generation timings. 23.
[0025]
The reception processing unit 22 performs various processes on the analog reception signal from the antenna 17 to obtain standard time information included in the long wave standard radio wave. As shown in FIG. 6, the reception processing unit 22 includes a tuning circuit 50, an amplification circuit 51, a bandpass filter 52, a demodulation circuit 53, an AGC (Automatic Gain Control) circuit 54, and a decoding circuit 55. ing. The tuning circuit 50 includes a plurality of tuning capacitors (not shown) connected in parallel with the coil of the antenna 17, and the capacitance of each tuning capacitor is preset so as to tune to a desired frequency. That is, a tuning capacitor connected to the antenna 17 is switched by an analog switch or the like based on a switching control signal from the control unit 23, and a reception frequency is switched, so that a plurality of stations (for example, JJY Fukushima station 40 kHz, JJY Kyushu station 60 kHz, etc.). ) To select a station to receive from. The amplifier circuit 51 amplifies the analog reception signal from the tuning circuit 50 and supplies it to the bandpass filter 52. The band pass filter 52 supplies only a predetermined frequency component of the analog reception signal to the demodulation circuit 53. The demodulation circuit 53 smoothes and demodulates the input analog reception signal. The AGC circuit 54 compares the level of the output signal of the demodulation circuit 53 with a predetermined level, and adjusts the signal amplification factor in the amplification circuit 51 so that the reception level of the long wave standard radio wave becomes constant. The decoding circuit 55 performs A / D conversion on the demodulated analog reception signal to obtain a digital signal, and decodes a time code indicating current time information from the digital signal. As is well known, this time code includes minute information indicating the current minute, hour information indicating the current time, and date information indicating the current date (the total date from January 1 of the year). These pieces of information are output from the reception processing unit 22 to the control unit 23 shown in FIG.
[0026]
The control unit 23 centrally controls each part of the movement 16. The control unit 23 includes a reception control circuit unit 41, a drive control circuit unit 42, a second counter circuit 43, and an hour / minute counter circuit 44. Further, the second counter circuit 43 includes a second position counter 431, a second time counter 432, and a second coincidence detection circuit 433. The hour / minute counter circuit 44 includes an hour / minute position counter 441, an hour / minute time counter 442, and an hour / minute coincidence. A detection circuit 443 is provided. The drive control circuit unit 42 is a circuit that generates a drive pulse signal that is a signal for moving the second hand, the minute hand, and the hour hand based on various pulse signals output from the oscillation unit 21. Normally, the drive control circuit unit 42 outputs a pulse signal for advancing the second hand at a cycle of 1 second, and outputs a pulse signal for advancing the minute hand at a cycle of 1 minute. On the other hand, when the display time is corrected, the drive control circuit unit 42 outputs a pulse signal for fast-forwarding each pointer display position at a cycle shorter than usual.
[0027]
The drive unit 24 includes a second drive circuit 31 and an hour / minute drive circuit 32. The second drive circuit 31 is a circuit that operates the second motor 25 that is a motor for driving the second hand based on various drive pulses supplied from the drive control circuit unit 42 in the control unit 23. The hour / minute drive circuit 32 is a circuit for operating the hour / minute motor 26 which is a motor for driving the minute hand based on various drive pulses supplied from the drive control circuit unit 42. In the description using FIG. 2, only the second motor 25 is illustrated, but here, the description is made with a configuration having two motors of the second motor 25 and the hour / minute motor 26. With the two-motor configuration, the second hand and the minute hand can be driven independently of each other, which has the advantage that the time required to move the hand position for time correction can be shortened. The second motor 25 and the hour / minute motor 26 are so-called stepping motors. The battery 27 supplies power to the movement 16. The battery 27 is a coin-type primary battery such as a lithium battery or a silver battery. Note that a secondary battery such as a lithium ion battery is used as the battery 27 when power is generated by a solar panel or the like.
[0028]
Here, the display time correction operation based on the time code is performed by the reception control circuit unit 41, the second counter circuit 43, and the hour / minute counter circuit 44 under the control of the drive control circuit unit 42. Specifically, when the time code is supplied, the reception control circuit unit 41 generates two data, that is, data corresponding to the second and data corresponding to the hour and minute based on the time code, and indicates the second. The data is set as the initial value of the second time counter 432 in the second counter circuit 43, and the data indicating the hour and minute are set as the initial value of the hour / minute time counter 442 of the hour / minute counter circuit 44, respectively.
[0029]
Then, the second time counter 432 increments the value set as the initial value in synchronization with the 1-second cycle pulse from the oscillation unit 21 in a 1-second cycle, and the count result is used as current second data indicating the current second. Output to the second coincidence detection circuit 433. Similarly, the hour / minute time counter 442 increments the value set as the initial value in synchronization with the one-minute period pulse from the oscillating unit 21 in a one-minute period, and the count result indicates the current hour / minute indicating the current hour / minute. The data is output to the hour / minute coincidence detection circuit 443.
[0030]
Thereafter, the drive control circuit unit 42 obtains the time indicated by the second hand, the minute hand, and the hour hand by reading a magnetic information pattern (not shown) of the hand movement mechanism, and obtains data representing the second in the second counter circuit 43. As the initial value of the second position counter 431, data representing the hour and minute are set as the initial value of the hour / minute position counter 441 in the hour / minute counter circuit 44, respectively. The second position counter 431 to which the initial value is set increments the value at a cycle of one second, and outputs the value to the second coincidence detection circuit 433 as display second data indicating the second. Similarly, the hour / minute position counter 441 increments the value at a cycle of one minute and outputs the value to the hour / minute coincidence detection circuit 443 as display hour / minute data indicating the hour / minute.
[0031]
Then, the drive control circuit unit 42 starts a current time return operation for adjusting the display time to the current time. First, the drive control circuit unit 42 sends an operation of sending a fast-forwarding pulse for second driving to the second driving circuit 31 and the second position counter 431 of the driving unit 24 and a time-minute driving circuit of the driving unit 24 for sending a fast-forwarding pulse for hour / minute driving. 32 and the operation to send to the hour / minute position counter 441 is started. As a result, the second position counter 431 starts counting fast-forwarding pulses for second driving, and the hour / minute position counter 441 starts counting fast-forwarding pulses for hour / minute driving.
[0032]
As a result, the second hand, the minute hand, and the hour hand are fast-forwarded, and the display second data gradually approaches the value of the current second data, and the display time / minute data approaches the current hour / minute data. The coincidence between the value of the display second data and the value of the current second data is detected by the second coincidence detection circuit 433, and the coincidence between the value of the display time / minute data and the value of the current hour / minute data is detected by the hour / minute coincidence detection circuit 443. When detected, the drive control circuit unit 42 stops outputting the fast-forwarding pulses for second driving and hour / minute driving, outputs a normal driving pulse, and the time correction operation based on the time code is completed.
[0033]
As described above, according to the radio wave correction wristwatch 1 of the present embodiment, the antenna 17 is disposed in the space formed by cutting the thick portion of the side wall of the case 12, and the end surface thereof is arranged with the gap between the inner surface of the space. As a result, a gap is provided between the both end faces 17a, 17b and the inner side surface of the space 122, and deterioration of reception sensitivity can be prevented. Further, since the distance between the antenna 17 and the inner surface of the case 12 can be separated only around the antenna 17, the dimensions (outer shape) of the case 12 remain the same as those of the conventional case to ensure the antenna characteristics. It is possible to prevent the case 12 from becoming large because the antenna 17 is disposed. Furthermore, the case 12 formed of a metal material which is a conductive member such as stainless steel, brass and titanium can give a high-class feeling as a watch.
[0034]
Second Embodiment
FIG. 7 is a bottom view showing the configuration of the radio wave correction wristwatch 1 according to the second embodiment of the present invention (a state where the back cover 14 is removed). The radio wave correction wristwatch 1 of this embodiment is different from the first embodiment in that a plastic resin material or the like is used as a fixing member 150 for fixing the antenna 17 after the antenna 17 is disposed in the space 122 formed in the case 12. The point is that the non-conductive member is filled in the space 122 to wrap around the antenna 17. With such a configuration, the antenna 17 can be fixed while preventing the reception characteristics of the antenna 17 from being deteriorated, and the plastic resin material functions as a buffer material. It becomes possible to improve the property. In the figure, the fixing member 150 is not disposed on the upper surface of the antenna 17, but it goes without saying that the fixing member 150 may also be disposed on the antenna 17.
[0035]
<Third Embodiment>
FIG. 8 is an exploded perspective view showing the configuration of the radio-controlled wristwatch 1 according to the third embodiment of the present invention. In the figure, the back cover 14 is shown in the upper part of the figure. The radio wave correction wristwatch 1 of the present embodiment is different from the first embodiment in that the back cover 14 is integrally formed from ceramic which is a non-conductive member, and is screwed and fixed so as to cover the opening on the lower surface of the case 12. Is a point. As the ceramic material, zirconia or the like that transmits long-wave radio waves can be used. In addition, ceramics have a gloss similar to that of metal when mixed with metal powder during sintering.
Even when the back cover 14 made of ceramic is used, the reception sensitivity of the antenna 17 can be improved by disposing the back cover 14 below the space where the antenna 17 is disposed.
[0036]
<Fourth embodiment>
FIG. 9 is an exploded perspective view showing the configuration of the radio-controlled wristwatch 1 according to the fifth embodiment of the present invention (with the back cover 14 upward), and FIG. 10 is a cross-sectional view of the radio-controlled wristwatch 1. The radio-controlled wristwatch 1 according to the present embodiment is different from the first embodiment in the following three points. That is, (1) a point provided with a middle frame 155 for fixing the movement 16, (2) a point provided with a solar panel 157 for power generation, and (3) a side wall of the case 12 in order to make the outer shape of the back cover 14 circular. Is cut out along the arc to form a space 122.
[0037]
The middle frame 155 is made of a non-conductive member such as a plastic material formed in a ring shape, and is disposed along the inner wall of the case 12 as shown in FIG. 10, and the antenna 17 and the movement 16 are arranged in the middle frame 155. Positioned and fixed inside. That is, since the antenna 17 and the case 12 have a structure sandwiching the middle frame 155, by increasing the thickness of the middle frame 155, the distance between the inner side surface of the case 12 and the end surfaces 17a and 17b of the antenna 17 is increased. The reception sensitivity characteristic is improved.
In general, when a solar panel 157 for power generation is provided on a wristwatch, the solar panel 157 is disposed below the dial 15. Here, since the base material of the solar panel 157 is a metal material, there is a concern that the reception sensitivity of the antenna 17 may deteriorate. However, since the distance between the inner surface of the case 12 and the antenna 17 is increased by using the configuration including the middle frame 155 as described above, the magnetic field component of the radio wave is transmitted to the antenna 17 through this gap (that is, the middle frame 155). And deterioration of reception sensitivity can be prevented.
On the other hand, the back pig 14 is generally a circular one. Therefore, by forming the space 122 in a shape that fits the circular back cover 14 as described above, the conventional circular back cover 14 can be diverted, and the appearance can be improved and the manufacturing cost can be reduced. It becomes possible.
[0038]
<Modification>
Each of the above-described embodiments is merely an aspect of the present invention, and can be arbitrarily modified within the scope of the present invention. Accordingly, various modifications will be described below.
[0039]
(1) In each embodiment mentioned above, you may form the space 122 for arrange | positioning the antenna 17 as follows. That is, as shown in FIG. 11, the case 12 has band attaching portions 121A and 121B at approximately 9 o'clock and 6 o'clock directions of the watch, but in each of the above-described embodiments, one of the band attaching portions 121 is provided. A space 122 was formed by scraping the inner surface of the case 12 toward the direction (see FIG. 2). On the other hand, the inner surface of the case 12 is scraped toward each of the two band mounting portions 121A and 121B to form spaces 122A and 122B, and the end surfaces 17a and 17b of the antenna 17 face the spaces 122A and 122B. A configuration in which the antenna 17 is arranged on the antenna, that is, an arrangement configuration in which the antenna arrangement shown in FIG. 2 is rotated 90 degrees clockwise may be employed.
According to this configuration, the length (full length) of the antenna 17 can be increased, and thereby the directivity of the antenna 17 can be sharpened.
[0040]
(2) In each of the above-described embodiments, as an example of the radio wave correction wristwatch 1, an analog timepiece that displays time by an hour hand is illustrated. However, the present invention is not limited thereto, and is not limited to an LED (Light Emitting Diode) or an organic EL (Electro Luminescent). It may be a digital clock that digitally displays the time.
(3) In each of the above-described embodiments, the radio-controlled wristwatch that receives a long-wave standard radio wave is illustrated as an example of a wristwatch with a wireless function. However, any wristwatch that has a built-in bar antenna that receives radio waves can be used. The present invention can be applied. For example, a wristwatch that realizes an RF-ID (Radio Frequency Identification) function by receiving radio waves in the 125 kHz band, a wristwatch that realizes a beacon function by receiving radio waves in the 457 kHz band, or a wristwatch that realizes an AM radio function In addition, the present invention can be applied.
[0041]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a wristwatch with a wireless function that can prevent deterioration of reception sensitivity of a built-in antenna without increasing the case diameter of the watch.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view showing a configuration of a radio wave correction wristwatch according to a first embodiment of the present invention.
FIGS. 2A and 2B are diagrams showing a configuration of the radio-controlled wristwatch, wherein FIG. 2A is a cross-sectional view, and FIG. 2B is a bottom view (without a back cover).
FIG. 3 is a conceptual diagram illustrating reception of a long wave standard radio wave by the antenna.
FIG. 4 is a perspective view showing a hand movement mechanism that is one component of the movement.
FIG. 5 is a block diagram showing an electrical configuration of the movement.
FIG. 6 is a block diagram showing an electrical configuration of the reception processing unit.
FIG. 7 is a bottom view (without a back cover) showing a configuration of a radio wave correction wristwatch according to a second embodiment of the present invention.
FIG. 8 is an exploded perspective view showing a configuration of a radio wave correction wristwatch according to a third embodiment of the present invention.
FIG. 9 is an exploded perspective view showing a configuration of a radio wave correction wristwatch according to a fourth embodiment of the present invention.
FIG. 10 is a cross-sectional view showing a configuration of the radio wave correction wristwatch.
FIG. 11 is a bottom view (no back cover) showing the configuration of a radio wave correction wristwatch according to a modification of the present invention.
FIG. 12 is a diagram schematically showing the relationship between the coil cross-sectional area of the loop antenna and the core length and directivity, (a) showing the directivity when the coil cross-sectional area is small and the core length is large; (B) shows the directivity when the coil cross-sectional area is large and the core length is small.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Radio wave correction wristwatch, 11 ... Cover glass, 12 ... Case, 14 ... Back cover, 15 ... Dial, 16 ... Movement, 17 ... Antenna (bar antenna), 18 ... Watch band, 121 ... Band attaching part, 122 ... Space 141 outer frame 142 glass plate 150 fixing member 155 middle frame

Claims (7)

A back cover made of at least a part of a conductive member, a movement arranged on the back cover for realizing a timekeeping function, a case made of a conductive member for covering the back cover and the movement from above, and in the case A bar antenna that is housed with the movement and receives radio waves from the outside;
A recess is provided on the inner side surface opposite to both end faces of the bar antenna disposed in the case, and a space is provided between the both end faces of the bar antenna and the inner side face of the case by the recess. Features a wireless wristwatch. The non-conductive member of the back cover is located below the recess formed by cutting at least the inner surface of the case.
The wristwatch with a wireless function according to claim 1. The said back pig is equipped with the frame material which consists of metal materials, and the glass material fitted to the said frame material.
The wristwatch with a wireless function according to claim 1. The back cover is formed from a ceramic material.
The wristwatch with a wireless function according to claim 1. A fixing member made of a non-conductive material for fixing the bar antenna disposed in the case is provided.
The wristwatch with a wireless function according to claim 1. Provided with a middle frame made of a non-conductive material for fixing the movement to the case
The wristwatch with a wireless function according to claim 1. Further equipped with a dial for visually recognizing time,
The dial is made of a non-conductive member.
The wristwatch with a wireless function according to claim 1.

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