Timepiece with wireless communication function
A timepiece with a wireless function, including a movement for displaying time; a conductive case that holds the movement; a crystal that is disposed on the face side of the case and covers the face side of the movement; a conductive plate that is electrically conductive, disposed between the movement and the crystal, and reflects radio waves; and an antenna that has a substantially annular, conductive antenna electrode, and is disposed along the outside edge of the conductive plate between the conductive plate and the crystal.
1. A timepiece with a wireless function, comprising:
a movement for displaying time;
a conductive case that holds the movement;
a crystal that is disposed on the face side of the case and covers the face side of the movement;
a dial that is made of non-conductive material;
a conductive plate that is electrically conductive, disposed between the movement and the dial, and reflects radio waves; and
an antenna that has a substantially annular, conductive antenna electrode, and is disposed along the outside edge of the conductive plate;
wherein the antenna is disposed between the dial and the crystal as seen in a lateral view.
2. The timepiece with a wireless function described in claim 1 , wherein:
the antenna has an annular dielectric substrate disposed along the outside edge of the conductive plate, a part of the annular dielectric substrate being disposed between the dial and the crystal as seen in the lateral view, and
the antenna electrode is disposed on the dielectric substrate.
3. The timepiece with a wireless function described in claim 1 , further comprising:
a solar panel that receives light and produces electrical power, and is disposed between the dial and the movement;
wherein the conductive plate further functions as a solar panel support substrate that supports the solar panel; and
wherein the dial is transparent.
4. The timepiece with a wireless function described in claim 1 , wherein:
the case has a signal reflection surface that is disposed to least one part of the end thereof on the crystal side and reflects signals entering from the crystal side to the antenna; and
the conductive plate is disposed with the outside edge thereof in contact with the inside circumference surface of the case.
5. The timepiece with a wireless function described in claim 1 , wherein:
the crystal has a face part that covers the face side of the movement when the timepiece with wireless function is seen in section view through the thickness of the timepiece, and a side part that is rendered around the outside circumference of the face part with an end surface thereof fastened to the case,
the end surface of the side part being fastened to the case at a position closer to a movement side than at least the top surface of the antenna opposing the face part.
6. The timepiece with a wireless function described in claim 1 , wherein:
the antenna has an annular dielectric substrate disposed along the outside edge of the conductive plate;
the antenna electrode includes a substantially annular main antenna unit disposed on the top surface of the dielectric substrate opposite the crystal,
one or more coupling units that branch to the side of the dielectric substrate from one or more junction nodes disposed to part of the main antenna unit, and
a power supply node that is formed contiguously to the opposite end of the coupling unit as the junction node on the bottom side of the dielectric substrate opposite the movement;
the conductive plate has a through-opening passing through the conductive plate in the timepiece thickness direction at a position opposite the power supply node; and
the timepiece further comprises a connection member that passes through the through-opening in the conductive plate, contacts the power supply node without contacting the conductive plate, and transmits to a reception unit that processes the reception signal based on radio waves received by the antenna.
7. The timepiece with a wireless function described in claim 1 , wherein:
the antenna receives circularly polarized waves.
8. The timepiece with a wireless function described in claim 1 , further comprising:
a dial ring that is made of non-conductive material and has a channel in which the antenna is held.
9. The timepiece with a wireless function described in claim 1 , further comprising:
a bezel that is made of non-conductive material and covers the antenna.
10. The timepiece with a wireless function described in claim 1 , wherein:
the antenna electrode is configured to receive radio waves reflected by the conductive plate.