Asymmetric digital watch module

• US 4,157,007 A
• Filed: 12/22/1976
• Issued: 06/05/1979
• Est. Priority Date: 12/22/1976
• Status: Expired due to Term

• Current Assignee: National Semiconductor Corporation (Texas Instruments, Inc.)
• Original Assignee: National Semiconductor Corporation (Texas Instruments, Inc.)
• Inventors: Vennard, John
• Primary Examiner(s): Witkowski, Stanley J.
• Application Number:
  US05/753,364
• Time in Patent Office: 895 Days
• Field of Search: 58/23 R, 58/50 R, 58/85.5, 58/88 R, 58/90 R
• US Class Current: 368/83
• CPC Class Codes: G04G 17/02 Component assemblies

Abstract

An electronic watch module includes a circuit board having all the electronic watch components including a plurality of LED'"'"'s and a CMOS integrated circuit device mounted on one side thereof defined as the face of the board. The board is of a generally flat circular configuration and having generally rectangular cutouts at the upper side thereof for mounting a crystal oscillator and a pair of arcuate slots or cutouts along the edge thereof for mounting a pair of elastomeric switch contact members. A cover for the board includes a transparent portion defining a transparent portion sealingly enclosing the LED'"'"'s and an opaque portion defining an opaque compartment for sealingly enclosing the CMOS integrated circuit device. The cover is hermetically sealed to the board for sealing these components. The overall layout of the circuit on the board is related to guide flats to facilitate automatic testing.

The method disclosed includes the mounting of the electronic components of the watch including a plurality of LED'"'"'s and a CMOS integrated circuit on the face of a selected printed circuit board by first screening an epoxy on selected areas of the surface of the circuit board and mounting the electronic components on the selected areas, curing the epoxy in a nitrogen purged oven, and thereafter hermetically sealing the electronic components of the watch module by means of a cover including a transparent portion sealingly enclosing the LED'"'"'s and an opaque portion sealingly enclosing the CMOS integrated circuit, the cover being mounted by the step of screening epoxy on the underside thereof placing the cover on the printed circuit board clipping the board and cover together and placing in an oven purged by nitrogen and heating for a period of time sufficient to cure the epoxy.

Claims

1. An electronic watch module having a thin profile, said module comprising:

a printed circuit board having a generally flat circular configuration defining a face and a back,

electronic watch components including display means mounted on said face of said board, and

a cover permanently secured to said face and defining walls spaced from and hermetically sealing said electric watch components on the face of said board, said cover having separate hermetically sealed compartments including a transparent portion covering said display means and an opaque portion covering other components on said face, the thickness of said module being defined substantially by the sum of the thickness of said board and the thickness of said cover.

3. The watch module of claim 1 including a plurality of cut out portions around the periphery of said board, one of said cut-outs defining alignment guide means for said board.

4. The watch module of claim 1 including a plurality of guide pins and cooperating guide bores for positively locating said cover on said board.

6. The watch module of claim 3, wherein one of said cutouts is adapted to receive an oscillator crystal, and a pair of said cutouts are adapted to receive a pair of resilient switch contact members.

7. The watch module of claim 6, wherein said switch contact members are elastomeric conductive members extending along in an arc in said cutouts.

8. The watch module of claim 7, wherein said conductive members are positioned in engagement with a pair of leads on said printed circuit board and are held in place by said cover.

9. The watch module of claim 3, wherein said cutout defining said alignment guide means is substantially rectangular in configuration for receiving and mounting a crystal oscillator, and

leads on said board adjacent said cutout for electrical connection to said oscillator.

10. The watch module of claim 9, including at least one arcuate shaped cutout adjacent said rectangular cutout for mounting an elongated elastomeric switch contact member in engagement with a lead on said board for providing switch contact means for controlling said electronics components.

11. The watch module of claim 10 including a further cutout substantially diametrically across from said arcuate cutout for mounting spring contact means for providing an electrical connection between a lead on said board and a watch case in which said module is mounted, and said spring contact means biasing said module toward the opposite side of said watch case.

12. The watch module of claim 7, wherein said switch contact members are generally Z-shaped in cross-section.

13. The watch module of claim 11, wherein said further cutout is also adapted to mount a trimmer capacitor, and said board includes leads for electrical connection to said trimmer capacitor.

15. The watch module of claim 11, wherein said cover is of a generally frusto-conical configuration tapering upward from said board to said transparent portion.

2. An electronic watch module of a thin profile, said module comprising:

a printed circuit board having a thin generally flat circular configuration defining a face and a back, and having alignment guide means associated therewith.

electronic watch components including display means mounted on said face of said board,

a plurality of probe pads located on the back of said board in predetermined positions with respect to said guide means and each pad connected to one of said electronic watch components and thereby adapted for automatic external testing of said electronic watch components, and

a cover defining wall means spaced from and hermetically sealing said face of said board, said cover having a transparent portion covering said display means in spaced relation thereto and an opaque portion covering other electronic watch components on said face in spaced relation thereto, the thickness of said module consisting substantially of the thickness of said cover and the thickness of said printed circuit board.

5. The watch module of claim 2, wherein said display means includes a plurality of light emitting diodes, and said electronics includes a CMOS device having means for computing time and means for driving means with decoded time keeping signals.

14. The watch module of claim 2, wherein said transparent portion is generaly rectangular in configuration and said cover tapers upward from said printed circuit board to said transparent portion.

16. The watch module of claim 5, wherein said pads are located with respect to guide means defined on said board for loading into a slotted rectangular tube for feeding into computer controlled machines for testing.

17. The watch module of claim 16, wherein said CMOS device includes digital frequency control, and said device includes count down ratio means for compensating the frequency of said oscillator, and said frequency is trimmed during final testing by conductor means selectively connecting a selected one of a plurality of pads located on the back of said circuit board into said circuit.

18. The watch module of claim 2, wherein the back of said board includes an insulating cover covering electrical contacts thereon.

19. The watch module of claim 18 wherein said cover is an adhesive backed Mylor disc.

20. The watch module of claim 17 including a Mylor insulating disc covering the back of said module.

21. The watch module of claim 2 including a Mylor disc covering the face of said module.

22. The watch module of claim 18 including a black Mylor disc covering the face of said module.