JP2019060897A - Electric wave wrist watch - Google Patents

Abstract

To provide an electric wave wrist watch capable of improving characteristics of a planar antenna.SOLUTION: An electric wave wrist watch includes a planar antenna 11 for receiving an electric wave including time information, an antenna substrate on which the planar antenna 11 is loaded, a rear cover constituted of a conductive member, a battery 10, and a body for storing the planar antenna 11 and the battery 10, where a ground of the antenna substrate is electrically connected to the rear cover through a contact point C provided in a region of the rear cover, which is overlapped on the planar antenna 11 in a plan view, and the contact point C is provided at a side closer to the body rather than the battery 10 out of the inside of a region which is overlapped on the planar antenna 11.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a radio-controlled watch that receives radio waves using a flat antenna.

  There is known a radio-controlled watch that receives radio waves transmitted from a time information source and corrects the time using time information included in the radio waves. Among such radio-controlled watches, for example, there are those using a flat antenna such as a patch antenna to receive radio waves, such as a satellite radio-controlled watch that receives radio waves from a GPS (Global Positioning System) satellite ( See, for example, Patent Document 1).

JP, 2013-40793, A

  In the radio-controlled watch as described above, it is desirable to improve the characteristics (gain) of the planar antenna in order to enhance the reception sensitivity of radio waves. The present invention has been made in consideration of such problems, and one of the objects thereof is to provide a radio-controlled watch capable of improving the characteristics of a flat antenna.

  In order to solve the above problems, the invention disclosed in the present application has various aspects, and the outline of typical ones of the aspects are as follows.

  (1) An antenna for receiving radio waves including time information, an antenna substrate on which the antenna is mounted, a back cover formed of a conductive member, a battery, and a case for housing the antenna and the battery The ground of the antenna substrate and the back cover are electrically connected to each other through a contact provided in a region of the back cover that overlaps with the antenna in plan view, and the contact is the region The radio-controlled watch which is provided on the side closer to the body than the battery among the inside.

  (2) In (1), the antenna is a planar antenna, and the contact point is disposed at a position closer to the center line in the lateral direction than the distance to both side surfaces of the planar antenna Radio wave watch characterized by.

  (3) The radio-controlled watch according to (2), wherein a plurality of the contacts are provided, and the plurality of contacts are provided so as to be symmetrical with respect to the center line.

  (4) In any one of (1) to (3), a conductive member provided with a spring for biasing the antenna substrate in the opposite direction to the back lid, between the antenna substrate and the back lid And the conductive member is electrically connected to the ground of the antenna substrate, and the back cover and the spring are electrically connected via the contact.

  (5) In any one of (1) to (4), the ground of the antenna substrate is electrically connected to the back lid through a plurality of contacts provided in the region. Radio watch.

  (6) The radio-controlled watch according to any one of (1) to (5), wherein the antenna is disposed in an area on one side of a bisector passing through the center of the radio-controlled watch.

  According to the aspects of the above (1) to (6), the gain of the antenna can be improved.

FIG. 1 is a plan view showing an appearance of a radio-controlled watch according to an embodiment of the present invention. It is the top view which looked at the movement accommodated in the case inside of a radio controlled watch from the back side. It is a schematic exploded perspective view of a movement. It is sectional drawing which shows the cross section containing the battery of a movement.

  Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

  FIG. 1 is a plan view showing a radio-controlled watch 100 according to an embodiment of the present invention. In the figure, there are shown a case 1 constituting a case (exterior) of the radio-controlled watch 100, a dial 2 disposed in the case 1 and an hour hand 3, a minute hand 4 and a second hand 5 which are hands indicating time. In addition, a crown 6 and a push button 7 for the user to perform various operations are disposed on the side of the body 1 at the 3 o'clock side. A band fixing portion 8 for fixing the band extends from the side surfaces on the 12 o'clock side and the 6 o'clock side of the cylinder 1.

  The design of the radio-controlled watch 100 shown in the figure is an example. Besides the one shown here, for example, the cylinder 1 may be square instead of round, and the presence, number, and arrangement of the push buttons 7 are arbitrary. Further, in the present embodiment, the hands are set to three of the hour hand 3, the minute hand 4 and the second hand 5, but the invention is not limited thereto. Even if the second hand 5 is omitted, the day of the week, the presence or absence of a time zone or summer time, radio waves The status of reception, remaining battery power, guidelines for various displays, date display, etc. may be added. Further, the case of the radio-controlled watch 100 is composed of a body 1 and a back cover 9 which does not appear in FIG. Both the body 1 and the back cover 9 may be made of metal, or the body 1 may be made of a material other than metal, for example, ceramic. In any case, the back cover 9 constituting the case in the present embodiment is formed of a conductive member such as metal.

  In the present specification, the term radio-controlled watch is used to indicate a radio-controlled watch and a watch. In the present embodiment, the radio-controlled watch 100 receives the satellite signal from a satellite (such as a GPS satellite) that transmits a satellite signal including information on date and time, and information on the date and time included in the received satellite signal, ie, Based on the reference time information, the internal time which is information of the time held inside the wristwatch is corrected. The radio signal received by the radio wristwatch 100 is not limited to the satellite signal, and is not particularly limited as long as it is a signal including reference time information. However, since it is a radio wave signal suitably received by the planar antenna 11 described later, it is preferable that the high frequency signal is a short wave to an ultra high frequency wave.

  Note that, in the radio-controlled watch 100, a windshield made of a transparent material such as glass is attached to the body 1 so as to cover the dial 2. In addition, on the opposite side of the windshield, a back cover 9 is attached to the cylinder 1. In the present specification, hereinafter, the direction in which the windshield of the radio-controlled watch 100 is disposed (front direction in FIG. 1) will be referred to as front side, and the direction in which the back cover 9 is disposed (back direction in FIG. 1) will be referred to as back side.

  On the back side of the dial 2, the battery 10 and the planar antenna 11 are arranged so as not to overlap in plan view. In the present embodiment, the battery 10 is a disk-shaped lithium secondary battery, and stores the power generated by the solar battery provided on the back side of the dial 2. Therefore, the dial 2 is transparent or translucent. The type of the battery 10 is not particularly limited, and may be a primary battery. In that case, the solar cell may not be provided, and the dial 2 may not have transparency. Further, in the present embodiment, the back surface and the side surface of the battery 10 constitute a positive electrode, and the front surface constitutes a negative electrode. Then, the potential of the positive electrode of the battery 10 becomes the reference potential of the radio-controlled watch 100, that is, the so-called potential of the ground.

  In the present embodiment, the planar antenna 11 is a patch antenna having a substantially rectangular flat plate shape, and is disposed parallel to the dial 2 and the back cover 9 near the 12 o'clock direction on the back side of the dial 2. The radio signal received by the planar antenna 11 is a satellite signal from a GPS satellite and is an ultra high frequency wave. In the present embodiment, the feeding electrode of the planar antenna 11 is disposed on the back side, and is connected to the electrode provided on the side surface on the 12 o'clock side to constitute a strip electrode. The feed electrode detects the current flowing in the detection target area 11 a along the left and right side surfaces of the reception surface disposed on the upper surface of the planar antenna 11. Specifically, as shown in FIG. 1, the detection target area 11 a is formed along the side of the upper surface of the planar antenna 11 in the 3 o'clock direction and the side in the 9 o'clock direction. The detection target area 11 a is mainly used for reception of radio waves by the planar antenna 11.

  FIG. 2 is a plan view of the movement 101 housed inside the case of the radio-controlled watch 100 as viewed from the back side. The movement 101 has a configuration in which the respective members are assembled to a base plate 12 made of a substantially circular insulating material that serves as a support frame. In FIG. 2, there is seen a winding stem 13 to which the crown 6 is attached so as to protrude from the movement 101 in the left direction in the drawing. Therefore, in the figure, the left direction corresponds to the 3 o'clock direction in FIG. 1, the right direction is the 9 o'clock direction, the upper direction is the 12 o'clock direction, and the lower direction is the 6 o'clock direction.

  As shown in FIG. 2, in the 6 o'clock direction on the back side of the movement 101, a battery holder 14 configured by a circular conductive member is disposed so as to cover the battery 10. Further, in the area on the back side of the movement 101 except for the battery holder 14, a magnetic shield 15 made of a substantially crescent-shaped conductive member is disposed. The battery holder 14 is in electrical contact with the positive electrode on the back side of the battery 10, and is screwed to the magnetic shield 15 by the screw 14a and is also conductive to the magnetic shield 15. As described later, the ground of the flat antenna substrate 16 on which the flat antenna 11 is mounted is also electrically connected to the positive electrode of the battery 10. Thus, the ground of the planar antenna substrate 16 is electrically connected to the magnetic shield 15.

  Furthermore, a spring 15a formed of an elastic tongue-like protrusion is disposed on the back side of the end of the antimagnetic plate 15 opposite to the battery holder 14 (i.e., 12 o'clock direction). When the movement 101 is housed in the case, the contact point C at the tip of the spring 15a contacts the surface on the front side of the back cover 9, thereby electrically connecting the antimagnetic plate 15 and the back cover 9. Further, the antimagnetic plate 15 is urged to the front side by the elasticity of the spring 15a, and the members inside the movement 101 including the planar antenna substrate 16 are pressed and fixed to the ground plate 12 side.

  In this manner, the ground of the planar antenna substrate 16 is electrically connected to the magnetic shield 15, and the magnetic shield 15 is electrically connected to the back cover 9 through the contact C, whereby the back cover 9 becomes the ground of the planar antenna 16. Electrically connected, the back cover 9 serves as a ground. Thus, the ground for the planar antenna 11 can be sufficiently secured by utilizing the back cover 9, which is a large conductive member as a ground, as compared to other members.

  Moreover, in FIG. 2, the position of the planar antenna 11 is shown by the broken line. As is clear from the figure, the tip of the spring 15a (that is, the contact point C between the antimagnetic plate 15 and the back cover 9) is located in a region overlapping with the planar antenna 11 in plan view. That is, when viewed in a direction perpendicular to the back cover 9 and the dial 2, the contact point C is in a region overlapping with the planar antenna 11. As a result, the region of the back cover 9 that faces the flat antenna 11 in particular can be reliably grounded and maintained at the reference potential. The inventors of the present application have found that the gain of the planar antenna 11 can be improved by arranging the contact point C in a region overlapping the planar antenna 11 in plan view as shown in FIG. 2 as a result of research. This is because the electric potential distribution on the back cover 9 tends to be asymmetrical with respect to the planar antenna 11 when the contact point is provided at a position away from the planar antenna 11, which adversely affects the reception characteristics of the two detection target areas 11a of the planar antenna 11. The reason is that Therefore, the gain improvement of the planar antenna 11 can be expected by providing the contact points C in an area near the two detection target areas 11a, in particular, even in the area overlapping with the planar antenna 11 in plan view of the back cover 9. Here, a center line parallel to the detection target area 11 a of the planar antenna 11 (that is, a center line in the left-right direction) is taken as a center line L. In FIG. 2, the center line L is indicated by an alternate long and short dash line. At this time, it is more preferable to arrange the contact point C at a position closer to the center line L than the distance to the left and right side surfaces of the planar antenna 11.

  Here, only one spring 15 a is provided on the magnetic plate 15. Therefore, the contact point C between the magnetic plate 15 and the back cover 9 is also only one. However, the present invention is not limited to this, and a plurality of contact points C may be provided in a region overlapping with the planar antenna 11 of the back cover 9. For example, a plurality of springs 15 a may be formed side by side on the magnetic shield plate 15, and the tips of the plurality of springs 15 a may be configured to contact the back cover 9, respectively. By so doing, the ground of the planar antenna substrate 16 and the back cover 9 can be electrically connected more reliably. Furthermore, it is more preferable that the plurality of contact points C formed by the plurality of springs 15 a be provided so as to be symmetrical with respect to the center line L.

  Next, an electrical connection path between the planar antenna substrate 16 and the magnetic shield plate 15 will be described with reference to FIGS. 3 and 4.

  FIG. 3 is a schematic exploded perspective view of the movement 101. As shown in FIG. In the figure, the upper direction is the back side, and the lower direction is the front side. The lowermost part of FIG. 3 shows a state in which a driving component such as a motor is accommodated in the main plate 12, and the timepiece circuit board 21 and the circuit pressing plate 22 are disposed in an overlapping manner. The watch circuit board 21 is a board on which various electronic components such as a control circuit for realizing a timekeeping function are mounted. A rectangular notch is provided at a position on the 12 o'clock side of the timepiece circuit board 21, and this is for accommodating the substantially rectangular planar antenna 11. The circuit pressing plate 22 is disposed so as to be electrically connected to the timepiece circuit board 21 and fixes the timepiece circuit board 21 to the ground plate 12 side. Furthermore, on the back side, the planar antenna substrate 16 is disposed. A planar antenna 11 is disposed at a position of 12 o'clock on the front side of the planar antenna substrate 16. Further, on the planar antenna substrate 16, a high frequency circuit for reception by the planar antenna 11 is also mounted. A circular notch is provided at a position on the 6 o'clock side of the flat antenna substrate 16, that is, a position opposite to the rectangular notch of the watch circuit board 21, and the roughly circular battery 10 is accommodated. ing. On the back side of the battery 10 and the planar antenna substrate 16, the above-described battery retainer 14 and the magnetic shield 15 are disposed. The members constituting the movement 101 described above are fixed by inserting a cylindrical columnar member 23 into a hole provided in each member and screwing it.

  FIG. 4 is a cross-sectional view of the movement 101 viewed from the 6 o'clock direction with the back side facing upward. That is, the front side of the drawing is the 6 o'clock direction, the back direction is the 12 o'clock direction, the right direction is the 9 o'clock direction, and the left direction is the 3 o'clock direction. 4 shows a cross section passing through the battery 10 of the movement 101, it is a schematic cross sectional view showing the positional relationship of each member constituting the movement 101. As shown in FIG. Therefore, in practice, members arranged offset in the depth direction of the drawing may be shown on the same plane in FIG.

  As shown in FIG. 3, although the magnetic shield 15 and the planar antenna substrate 16 are disposed so as to overlap each other, they are not directly conductive but insulated from each other. Instead, as shown in FIG. 4, the ground of the flat antenna substrate 16 is connected to the ground of the watch circuit substrate 21 via the conductive rubber 21 a attached to the watch circuit substrate 21. The ground of the planar antenna substrate 16 and the ground of the timepiece circuit substrate 21 are electrically connected via a columnar member 23 formed of a conductive member such as metal instead of or in addition to the conductive rubber 21a. You may do it. The ground of the timepiece circuit board 21 is electrically connected to a circuit pressing plate 22 formed of a conductive member. Further, the circuit holding plate 22 is formed with a connection terminal portion 22 a which protrudes so as to contact the positive electrode on the side surface of the battery 10. The circuit pressing plate 22 is electrically connected to the positive electrode of the battery 10 through the connection terminal portion 22a. Further, as described above, the positive electrode on the back side of the battery 10 is electrically connected to the back cover 9 via the battery holder 14 and the magnetic shield 15. As a result, the ground of the flat antenna substrate 16 is electrically connected to the back cover 9 and constitutes the reference potential of the radio-controlled watch 100 as a whole.

  According to the radio-controlled watch 100 according to the present embodiment described above, the contact point C on the back cover 9 electrically connecting the ground of the flat antenna substrate 16 and the back cover 9 overlaps the flat antenna 11 in plan view. By being disposed, the region of the back cover 9 overlapping with the planar antenna 11 can be reliably grounded, whereby the gain of the planar antenna 11 can be improved.

  The specific configuration shown in the embodiment described above is an example, and those skilled in the art may make various modifications. For example, the shape or number of each member or its portion may be changed as appropriate, and does not have to be the same as that illustrated. For example, the electrical paths shown in FIGS. 3 and 4 are merely an example, and the ground of the planar antenna substrate 16 may be electrically connected to the back cover 9 by another path. For example, similar to the electrical connection between the planar antenna substrate 16 and the clock circuit substrate 21 described above, each member in the movement 101 such as the magnetic shield plate 15 and the circuit pressing plate 22 is a columnar member made of a conductive member. It may be electrically connected through 23.

1 body, 2 letter board, 3 hour hand, 4 minute hand, 5 second hand, 6 crown, 7 push button, 8 band fixed part, 9 back cover, 10 batteries, 11 plane antenna, 11a detection target area, 12 base plate, 13 turns true , 14 battery holder, 14a screw, 15 magnetic plate, 15a
Spring, 16 flat antenna boards, 21 watch circuit boards, 21a conductive rubber, 22 circuit holding plates, 22a connection terminals, 23 pillars, 100 radio wristwatches, 101 movements.

Claims (6)

An antenna for receiving radio waves including time information;
An antenna substrate on which the antenna is mounted;
A back cover configured of a conductive member;
Battery,
A cylinder for housing the antenna and the battery;
Equipped with
The ground of the antenna substrate and the back cover are electrically connected via a contact point provided in a region of the back cover that overlaps the antenna in plan view,
The radio-controlled watch, wherein the contact point is provided on the side closer to the trunk than the battery in the area. The antenna is a planar antenna,
The radio-controlled watch according to claim 1, wherein the contact point is disposed at a position closer to the center line in the left-right direction than the distance to the left and right side surfaces of the planar antenna. Comprising a plurality of said contacts,
The radio-controlled watch according to claim 2, wherein the plurality of contacts are provided to be symmetrical with respect to the center line. Between the antenna substrate and the back cover, a conductive member provided with a spring that biases the antenna substrate toward the opposite side to the back cover is disposed.
The conductive member is electrically connected to the ground of the antenna substrate,
The radio-controlled watch according to any one of claims 1 to 3, wherein the back cover and the spring are electrically connected via the contact point. The ground of the said antenna board | substrate is electrically connected with the said back cover via the several contact provided in the said area | region. The electromagnetic wave of any one of the Claims 1-4 characterized by the above-mentioned. Watches. The radio-controlled watch according to any one of claims 1 to 5, wherein the antenna is disposed in an area on one side of a bisector passing through the center of the radio-controlled watch.

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