Wristwatch with pressure sensor

• US 4,783,772 A
• Filed: 02/29/1988
• Issued: 11/08/1988
• Est. Priority Date: 03/19/1985
• Status: Expired due to Term

• Current Assignee: Citizen Watch Co Limited (Citizen Electronics Company Limited)
• Original Assignee: Citizen Watch Co Limited (Citizen Electronics Company Limited)
• Inventors: Hiruta, Toshio, Yamada, Masato, Umemoto, Toshio, Mochida, Kunikazu, Uehara, Hideo
• Primary Examiner(s): Miska, Vit W.
• Application Number:
  US07/165,361
• Time in Patent Office: 253 Days
• Field of Search: 368/10, 368/11, 368/71, 368/278, 368/294, 368/295, 73/291, 73/384, 73/386, 73/437, 73/753-754
• US Class Current: 368/11
• CPC Class Codes: B63C 11/02 Divers' equipment
• CPC Class Codes: G01C 5/06 by using barometric means
• CPC Class Codes: G04B 47/066 with a pressure sensor
• CPC Class Codes: G04G 21/02 Detectors of external physical values, e.g. temperature

Abstract

An electronic diving wristwatch having a pressure sensing depth meter provided in a projection on a case of the watch without interferring with the existing crown, pushbuttons, etc. The depth meter has a piezoelectric type sensing element which produces electrical output in response to the water pressure. The output is converted to a water depth which is displayed in a digital display window of the watch.

Claims

1. A wristwatch having a case, and an internal module provided in the case, said module comprising a face portion having means for displaying the time and detected depth or altitude, the improvement comprising a projection exending laterally from said face portion in a plane substantially normal to the axis of said face portion, a pressure sensor which is provided in said projection and which is functionally connected to the module, means for detecting a depth or an altitude in response to the measurement of pressure by the pressure sensor, means for displaying the detected depth or altitude, and a protective plate mounted in a major surface of said projection and defining gap within said projection between said protective plate and said pressure sensor, with said pressure sensor being located below said gap and opposite a center portion of said protective plate, said protective plate being provided with openings through which the pressure acts on the pressure sensing element, said openings being located in the vicinity of an outer periphery of the protective plate.

2. A wristwatch according to claim 1, wherein said module comprises a printed circuit board having a predetermined conductor pattern and electronic elements thereon for controlling said time displaying means and wherein said pressure sensor comprises means for receiving a pressure acting thereon and means for producing electrical output in response to the pressure and means for sending the output to the printed circuit board.

3. A wristwatch according to claim 2, wherein said pressure receiving means comprises a layer made of soft resin material responsive to the pressure acting thereon and wherein said electrical output producing means comprises a semiconductor pressure sensr element.

4. A wristwatch according to claim 3 wherein said pressure sensing element is embedded in a gelled resin on which a rubber upper layer is located.

5. A wristwatch according to claim 4, wherein said semiconductor pressure sensing element comprises a bridge circuit including four piezo resistances, the output of which changes in response to the change of the pressure acting thereon through the soft resin layer.

6. A wristwatch according to claim 2, further comprising means for sealing the pressure sensor from the module in a fluid-tight fashion.

7. A wristwatch according to claim 6, wherein the displaying means comprises a digital display portion and an analog display portion.

8. A wristwatch according to claim 7, further comprising means for selecting information to be displayed in the digital display portion.

9. A wristwatch according to claim 8, further comprising means for converting the output of the pressure sensor to a depth or an attitude of water.

10. A wristwatch according to claim 9, wherein the depth or altitude of water is displayed in the digital display portion.

11. A wristwatch according to claim 7, further comprising a dial having 12 marks in the case which represent the hours of time and wherein said digital display portion comprises a display window and a liquid crystal cell displaying the information, said display window partially overlapping at least one of the marks.

12. A wristwatch according to claim 11, further comprising a rotatable register ring around the 12 marks, said register ring being partially overlapped above the protective plate in plan view.

13. A wristwatch according to claim 11, wherein said at least one mark is partially shifted from the circle on which the remaining marks are located, so that the at least one marks which is overlapped by the display window is visible.

14. A wristwatch according to claim 1, wherein said projection is located in a vicinity of the mark representing nine o'"'"'clock.

15. A wristwatch according to claim 1, wherein said means for displaying the time comprises a digital display without analog display, and wherein said projection is located on the periphery of the case in the direction of around the northwest in plan view.

16. A wristwatch according to claim 1, further comprising a plurality of external actuation members provided on the case, including a crown for adjusting the time and pushbuttons for selecting the information to be displayed in the digital display portion.

17. A wristwatch according to claim 5, wherein said gap is within a range of approximately 200 to 1000 μ

m.

18. A wristwatch according to claim 11, wherein said analog display portion comprises an hour hand, a minute hand which is longer than the hour hand, and a second hand, said minute hand having a length that it does not extend up to displayed numerals in the liquid crystal cell in the display window.