JP6883015B2 - Radio watch - Google Patents

Description

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

There is known a radio-controlled wristwatch that receives radio waves transmitted from a time information source and corrects the time using the time information contained in the radio waves. Some such radio-controlled wristwatches use a flat antenna such as a patch antenna to receive radio waves, such as a satellite radio-controlled wristwatch that receives radio waves from a GPS (Global Positioning System) satellite (for example). For example, see Patent Document 1).

Japanese Unexamined Patent Publication No. 2013-40793

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

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

(1) An antenna for receiving radio waves including time information, an antenna substrate on which the antenna is mounted, a back cover made of a conductive member, a battery, and a body for accommodating the antenna and the battery. The ground of the antenna substrate and the back cover are electrically connected via a contact provided in a region of the back cover that overlaps with the antenna in a plan view, and the contact is formed in the region. A radio wave watch characterized in that it is provided on the side closer to the body than the battery.

(2) In (1), the antenna is a planar antenna, and the contacts are arranged at positions where the distance to the center line in the left-right direction is closer than the distance to the left and right side surfaces of the planar antenna. A radio wave watch featuring.

(3) The radio-controlled wristwatch 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 urging the antenna board toward the opposite side of the back cover between the antenna board and the back cover. Is arranged, 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 cover via a plurality of contacts provided in the region. Radio-controlled wristwatch.

(6) In any of (1) to (5), the radio-controlled wristwatch is characterized in that the antenna is arranged in a region on one side of a dichotomized line passing through the center of the radio-controlled wristwatch.

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

It is a top view which shows the appearance of the radio-controlled wristwatch which concerns on embodiment of this invention. It is a top view of the movement housed inside the case of a radio-controlled wristwatch as seen from the back side. It is a schematic exploded perspective view of the movement. It is sectional drawing which shows the cross section including the battery of a movement.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

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

The design of the radio-controlled wristwatch 100 shown in the figure is an example. In addition to the ones shown here, for example, the body 1 may be square instead of round, and the presence / absence, number, and arrangement of push buttons 7 are arbitrary. Further, in the present embodiment, the pointers are three, the hour hand 3, the minute hand 4, and the second hand 5, but the present invention is not limited to this, and the second hand 5 may be omitted, or the day of the week, the presence or absence of the time zone or daylight saving time, and the radio wave. You may add a guideline for displaying the reception status of the radio wave, the remaining battery level, various displays, a date display, and the like. Further, the case of the radio-controlled wristwatch 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 made of a conductive member such as metal.

In this specification, the term radio-controlled wristwatch is used to refer to a radio-controlled wristwatch and a wristwatch. In the present embodiment, the radio wave watch 100 receives the satellite signal from a satellite (GPS satellite or the like) that transmits a satellite signal including information on the date and time, and the information on the date and time included in the received satellite signal, that is, Based on the reference time information, the internal time, which is the time information held inside the watch, shall be corrected. The radio wave signal received by the radio-controlled 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 signal preferably received by the planar antenna 11 described later, it is preferably a high frequency signal from a short wave to an ultra high frequency.

In the radio-controlled wristwatch 100, a windshield made of a transparent material such as glass is attached to the body 1 so as to cover the dial 2. Further, on the opposite side of the windshield, the back cover 9 is attached to the body 1. Hereinafter, in the present specification, the direction in which the windshield of the radio-controlled wristwatch 100 is arranged (the direction toward the front of the paper surface in FIG. 1) is referred to as the front side, and the direction in which the back cover 9 is arranged (the direction toward the back of the paper surface in FIG. 1) is referred to as the back side.

On the back side of the dial 2, the battery 10 and the flat antenna 11 are arranged so as not to overlap each other in a plan view. In the present embodiment, the battery 10 is a disk-shaped lithium secondary battery, and it is assumed that the electric power generated by the solar cell provided on the back side of the dial 2 is stored. 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 form the positive electrode, and the front surface constitutes the negative electrode. Then, the potential of the positive electrode of the battery 10 becomes the reference potential of the radio-controlled wristwatch 100, that is, the so-called ground potential.

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

FIG. 2 is a plan view of the movement 101 housed inside the case of the radio-controlled wristwatch 100 as viewed from the back side. The movement 101 has a configuration in which each member is assembled to a main plate 12 made of a substantially circular insulating material that serves as a support frame. In FIG. 2, the winding stem 13 to which the crown 6 is attached so as to protrude from the movement 101 can be seen 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 upward direction is the 12 o'clock direction, and the downward direction is the 6 o'clock direction.

As shown in FIG. 2, a battery retainer 14 composed of a circular conductive member is arranged so as to cover the battery 10 at 6 o'clock on the back side of the movement 101. Further, in the region excluding the battery retainer 14 on the back side of the movement 101, a magnetic resistance plate 15 composed of a substantially crescent-shaped conductive member is arranged. The battery retainer 14 is in contact with the positive electrode on the back side of the battery 10 and is electrically connected, and is further screwed to the magnetic resistant plate 15 by a screw 14a and is electrically connected to the magnetic resistant plate 15. As will be 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. As a result, the ground of the flat antenna substrate 16 is electrically connected to the magnetic resistance plate 15.

Further, at the end of the magnetic resistance plate 15 on the opposite side (that is, in the 12 o'clock direction) of the battery retainer 14, a spring 15a formed by elastic tongue-shaped protrusions is arranged so as to project to the back side. When the movement 101 is housed in the case, the contact C at the tip of the spring 15a comes into contact with the front surface of the back cover 9, whereby the magnetic resistance plate 15 and the back cover 9 become conductive. Further, the magnetic resistance plate 15 is urged to the front side by the elasticity of the spring 15a, and each member inside the movement 101 including the flat antenna substrate 16 is pressed against the main plate 12 side to be fixed.

In this way, the ground of the flat antenna substrate 16 is electrically connected to the anti-magnetic plate 15, and the anti-magnetic plate 15 conducts with the back cover 9 via the contact C, so that the back cover 9 becomes the ground of the flat antenna 16. It is electrically connected and the back cover 9 serves as a ground. By using the back cover 9, which is a large conductive member as compared with other members, as a ground in this way, a sufficient ground for the flat antenna 11 can be secured.

Further, in FIG. 2, the position of the planar antenna 11 is indicated by a broken line. As is clear from the figure, the tip of the spring 15a (that is, the contact point C between the magnetic resistance plate 15 and the back cover 9) is located in the region overlapping the flat antenna 11 in a plan view. That is, the contact C is in the region overlapping the flat antenna 11 when viewed from the direction perpendicular to the back cover 9 and the dial 2. As a result, the region of the back cover 9 facing particularly the flat antenna 11 can be reliably grounded and maintained at the reference potential. As a result of research, the inventors of the present application have found that the gain of the planar antenna 11 can be improved by arranging the contact C in a region overlapping the planar antenna 11 in a plan view as shown in FIG. This is because if the contact is provided at a position away from the flat antenna 11, the potential distribution on the back cover 9 tends to be asymmetric with respect to the flat antenna 11, which adversely affects the reception characteristics of the two detection target regions 11a of the flat antenna 11. Because it exerts. Therefore, among the regions that overlap with the planar antenna 11 in the plan view of the back cover 9, the gain of the planar antenna 11 can be expected to be improved by providing the contact C in a region close to an equidistant distance from the two detection target regions 11a. Here, the center line parallel to the detection target region 11a of the planar antenna 11 (that is, the center line in the left-right direction) is defined as the 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 C at a position where the distance to the center line L is shorter than the distance to the left and right side surfaces of the flat antenna 11.

Here, it is decided that only one spring 15a is provided on the anti-magnetic plate 15. Therefore, there is only one contact C between the magnetic resistance plate 15 and the back cover 9. However, the present invention is not limited to this, and a plurality of contacts C may be provided in the region of the back cover 9 that overlaps with the flat antenna 11. For example, the magnetic resistance plate 15 may be formed with a plurality of springs 15a arranged side by side, and the tips of the plurality of springs 15a may be configured to come into contact with the back cover 9, respectively. In this way, the ground of the flat antenna substrate 16 and the back cover 9 can be more reliably connected electrically. Further, it is more preferable that the plurality of contact points C formed by the plurality of springs 15a are provided so as to be symmetrical with respect to the center line L.

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

FIG. 3 is a schematic exploded perspective view of the movement 101. In the figure, the upper direction is the back side and the lower direction is the front side. At the bottom of FIG. 3, a drive component such as a motor is housed on the main plate 12, and a clock circuit board 21 and a circuit holding plate 22 are arranged on top of the main plate 12. The clock circuit board 21 is a board on which various electronic components such as a control circuit that realizes a timekeeping function are mounted. A rectangular notch is provided at a position on the 12 o'clock side of the clock circuit board 21, and this is for accommodating a substantially rectangular flat antenna 11. The circuit holding plate 22 is arranged so as to be electrically connected to the clock circuit board 21, and the clock circuit board 21 is fixed to the main plate 12 side. Further, a flat antenna substrate 16 is arranged on the back side thereof. A flat antenna 11 is arranged at a position on the front side of the flat antenna substrate 16 on the 12 o'clock side. Further, a high frequency circuit for reception by the flat antenna 11 is also mounted on the flat antenna substrate 16. A circular notch is provided at a position on the flat antenna board 16 on the 6 o'clock side, that is, a position opposite to the rectangular notch on the clock circuit board 21, and accommodates a substantially circular battery 10. ing. The battery holder 14 and the magnetic resistance plate 15 described above are arranged on the back side of the battery 10 and the flat antenna substrate 16, respectively. Each member constituting the movement 101 described above is fixed by inserting a cylindrical columnar member 23 into a hole provided in each member and screwing the member.

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 direction of the paper is 6 o'clock, the back direction is 12 o'clock, the right direction corresponds to 9 o'clock, and the left direction corresponds to 3 o'clock. Although FIG. 4 shows a cross section of the movement 101 passing through the battery 10, it is a schematic cross-sectional view showing the positional relationship of each member constituting the movement 101. Therefore, the members that are actually arranged offset in the depth direction of the drawing may be shown on the same plane in FIG.

As shown in FIG. 3, the magnetic resistance plate 15 and the flat antenna substrate 16 are arranged so as to be overlapped with each other, but they are not directly conductive and are 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 clock circuit board 21 via the conductive rubber 21a attached to the clock circuit board 21. The ground of the flat antenna substrate 16 and the ground of the clock circuit board 21 are conductive in place of or in addition to the conductive rubber 21a via a columnar member 23 formed of a conductive member such as metal. It may be that. The ground of the clock circuit board 21 is electrically connected to the circuit holding plate 22 made of a conductive member. Further, the circuit holding plate 22 is formed with a connection terminal portion 22a that projects so as to come into contact with the positive electrode on the side surface of the battery 10. The circuit holding plate 22 is electrically connected to the positive electrode of the battery 10 via 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 resistance plate 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 wristwatch 100 as a whole.

According to the radio wave watch 100 according to the present embodiment described above, the contact C on the back cover 9 that electrically connects the ground of the flat antenna substrate 16 and the back cover 9 is located in a region where the contact C on the back cover 9 overlaps with the flat antenna 11 in a plan view. By arranging the arrangement, the area of the back cover 9 overlapping with the flat antenna 11 can be reliably grounded, whereby the gain of the flat antenna 11 can be improved.

The specific configuration shown in the above-described embodiment is an example, and those skilled in the art may make various modifications. For example, the shape and number of each member or a portion thereof may be changed as appropriate, and it is not necessary that the members are the same as those shown in the figure. For example, the electrical path shown in FIGS. 3 and 4 is only an example, and the ground of the flat antenna substrate 16 may be electrically connected to the back cover 9 by another path. For example, similar to the electrical connection between the flat antenna board 16 and the clock circuit board 21 described above, each member in the movement 101 such as the magnetic resistance plate 15 and the circuit holding plate 22 is a columnar member made of a conductive member. It may be electrically connected via 23.

1 body, 2 dial, 3 hour hand, 4 minute hand, 5 second hand, 6 crown, 7 push button, 8 band fixing part, 9 back cover, 10 battery, 11 flat antenna, 11a detection target area, 12 base plate, 13 rolls , 14 Battery holder, 14a screw, 15 anti-magnetic plate, 15a
Spring, 16 flat antenna board, 21 clock circuit board, 21a conductive rubber, 22 circuit holding plate, 22a connection terminal, 23 columnar member, 100 radio-controlled wristwatch, 101 movement.

Claims (6)

An antenna that receives radio waves including time information,
The antenna board on which the antenna is mounted and
And batteries,
The body that houses the antenna and the battery,
A back cover made of a conductive member, which is provided so as to overlap the antenna substrate and the battery in a plan view and is attached to the body.
A contact that electrically connects the ground of the antenna board and the back cover,
With
A radio-controlled wristwatch characterized in that the contact is provided in a region overlapping the antenna in a plan view and is provided closer to the body than the battery. The antenna is a planar antenna.
The radio wave watch according to claim 1, wherein the contacts are arranged at a position where the distance to the center line in the left-right direction is closer than the distance to the left and right side surfaces of the flat antenna. With a plurality of the above contacts
The radio-controlled wristwatch according to claim 2, wherein the plurality of contacts are provided so as to be symmetrical with respect to the center line. A conductive member having a spring for urging the antenna board toward the opposite side of the back cover is arranged between the antenna board and the back cover.
The conductive member is electrically connected to the ground of the antenna substrate.
The radio-controlled wristwatch according to any one of claims 1 to 3, wherein the back cover and the spring are electrically connected via the contact point. The radio wave according to any one of claims 1 to 4, wherein the ground of the antenna substrate is electrically connected to the back cover via a plurality of contacts provided in the region. Watches. The radio-controlled wristwatch according to any one of claims 1 to 5, wherein the antenna is arranged in a region on one side of a dichotomy line passing through the center of the radio-controlled wristwatch.

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