Electronic timepiece with internal antenna

• US 8,570,838 B2
• Filed: 11/10/2011
• Issued: 10/29/2013
• Est. Priority Date: 11/12/2010
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Fujisawa, Teruhiko
• Primary Examiner(s): Miska, Vit W
• Application Number:
  US13/293,183
• Publication Number:
  US 20120120772A1
• Time in Patent Office: 719 Days
• Field of Search: 368/47, 343/718, 343/767
• US Class Current: 368/47
• CPC Class Codes: G04C 10/02 the power supply being a radioactive or photovoltaic source
• CPC Class Codes: G04R 60/06 Antennas attached to or integrated in clock or watch bodies
• CPC Class Codes: G04R 60/10 inside cases
• CPC Class Codes: G04R 60/12 inside metal cases
• CPC Class Codes: H01Q 1/273 Adaptation for carrying or wearing by persons or animals
• CPC Class Codes: H01Q 13/10 Resonant slot antennas
• CPC Class Codes: H01Q 9/0421 with a shorting wall or a shorting pin at one end of the element H01Q9/0414 takes precedence

Abstract

An electronic timepiece with internal antenna maintains sufficiently high reception performance of circularly polarized waves even when having a metal external case. The timepiece has a cylindrical case; a crystal that covers the opening on the face side of the case; a drive mechanism that arranged inside the case; a metal antenna; and a dielectric. The antenna houses the drive mechanism and has a cylindrical side part, a bottom part that covers the opening on the back side of the side part, and an antenna electrode that contacts the inside of the side part. The back cover covers the back side of the case and is also the bottom part. The dielectric extends circumferentially to the side part, and contacts the antenna electrode in the face-back cover direction. A slot extending circumferentially is formed in the antenna electrode. Part or all of the slot is covered by the dielectric.

Claims

1. An electronic timepiece with internal antenna, comprising:

a cylindrical external case;

a crystal that covers one of the two openings of the external case;

a drive mechanism that drives a hand inside the external case;

an antenna that has a cylindrical side part made of metal, a metal bottom part that covers one of the two openings of the side part, and a metal top part that extends transversely to the center axis of the side part inside the external case, and contacts the inside surface of the side part,

holds the drive mechanism between the bottom part and the top part, and has the top part disposed between the drive mechanism and the crystal; and

an annular dielectric that extends circumferentially to the side part and contacts the top part in the axial direction of the side part;

wherein the external case has a metal part that is made of metal,

the bottom part is a back cover that covers the other of the two openings of the external case,

the top part has a slot part that extends circumferentially to the side part and contacts the dielectric,

a slot that extends circumferentially to the side part is formed in the slot part, and

the dielectric covers part or all of the slot in the axial direction of the side part.

2. The electronic timepiece with internal antenna described in claim 1, wherein:

the metal part includes part or all of the side part.

3. The electronic timepiece with internal antenna described in claim 1, wherein:

the electronic timepiece further includes a dial disposed between the hand and the top part; and

the slot is disposed between the dial and the side part when seen from a direction perpendicular to the crystal.

4. The electronic timepiece with internal antenna described in claim 1, wherein:

the hand rotates on a center shaft;

the top part has a center part surround by the slot part; and

a hole through which the center shaft passes is open in the center part.

5. The electronic timepiece with internal antenna described in claim 4, further comprising:

an image display unit that displays an image and is disposed between the top part and the bottom part; and

a window for viewing the image is opened in the center part.

6. The electronic timepiece with internal antenna described in claim 1, further comprising:

a photovoltaic conversion panel that extends transversely to the center axis of the side part, and converts light energy to electrical energy, and

is disposed between the top part and the hand inside the slot part when seen from the axial direction of the side part.

7. The electronic timepiece with internal antenna described in claim 1, wherein:

the shape of the slot is a C-shape; and

the antenna has a power supply node at a specific position referenced to an end of the slot.