Circuit unit for electronic instrument having key-pad arrangement

• US 5,357,065 A
• Filed: 07/09/1993
• Issued: 10/18/1994
• Est. Priority Date: 07/10/1992
• Status: Expired due to Term

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Inagaki, Mitsuo, Mitamura, Fumio
• Primary Examiner(s): Scott, J. R.
• Application Number:
  US08/088,344
• Time in Patent Office: 466 Days
• Field of Search: 200/5 R,5 A, 200/512-517, 200/292, 361/748-751, 174/250, 174/253, 174/254, 174/255, 174/259, 174/268
• US Class Current: 200/5.00A
• CPC Class Codes: H01H 13/7006 comprising a separate movable contact element for each switch site, all other elements being integrated in layers
• CPC Class Codes: H01H 2207/02 Solder
• CPC Class Codes: H01H 2207/04 Details of printed conductors
• CPC Class Codes: H01H 2221/062 Damping vibrations
• CPC Class Codes: H01H 2229/02 Laser
• CPC Class Codes: H01H 2229/028 Adhesive
• CPC Class Codes: H04B 1/401 for selecting or indicating operating mode
• CPC Class Codes: H04M 1/0214 Foldable telephones, i.e. with body parts pivoting to an open position around an axis parallel to the plane they define in closed position combined with translation movement H04M1/0235
• CPC Class Codes: H04M 1/23 Construction or mounting of dials or of equivalent devices; Means for facilitating the use thereof by improving visibility H04M1/22

Abstract

A circuit unit is used in an electronic instrument having a key-pad arrangement, such as a portable telephone, and comprises a printed circuit board, a flexible switch circuit sheet attached to the printed circuit board and having a plurality of switch pads arranged thereon, and at least one circuit pattern formed in the flexible switch circuit sheet so as to construct a switch circuit together with the switch pads. The circuit pattern includes a plurality of line sections extended between the switch pads, and a plurality of terminals provided along a peripheral edge of the flexible switch circuit sheet for establishing an electrical connection between the printed circuit board and the flexible switch circuit sheet.

Claims

1. A circuit unit incorporated in an electronic instrument having a key-pad arrangement, which unit comprises:

a printed circuit board;

a flexible switch circuit sheet attached to said printed circuit board and having a plurality of switch pads arranged thereon; and

at least one circuit pattern formed in said flexible switch circuit sheet so as to construct a switch circuit together with said switch pads, said circuit pattern including a plurality of line sections extended between said switch pads, and a plurality of terminals provided along a peripheral edge of said flexible switch circuit sheet for establishing electric connection between said printed circuit board and said flexible switch circuit sheet.

2. A circuit unit as set forth in claim 1, wherein said flexible switch circuit sheet is adhered to said printed circuit board through the intermediary of a self-adhesive or pressure sensitive adhesive layer.

3. A circuit unit as set forth in claim 1, wherein each of said terminals is soldered to a corresponding terminal pad formed on said printed circuit board.

4. A circuit unit as set forth in claim 1, wherein said terminals are formed in substantially the same manner as a via-hole or through-hole is formed in a printed circuit board or sheet.

5. A circuit unit as set forth in claim 1, wherein each of said switch pads comprises a diaphragm pad formed of a suitable metal material such as copper.

6. A circuit unit as set forth in claim 1, wherein said flexible switch circuit sheet has a multi-layer structure, a central film layer of which has two circuit patterns formed on sides thereof for constructing said switch circuit.

7. A circuit unit as set forth in claim 6, wherein said multi-layer structure is adhered to said printed circuit board through the intermediary of a self-adhesive or pressure-sensitive adhesive layer.

8. A circuit unit as set forth in claim 6, wherein each of said terminals is soldered to a corresponding terminal pad formed on said printed circuit board.

9. A circuit unit as set forth in claim 6, wherein said terminals are formed in substantially the same manner as a via-hole or through-hole is formed in a printed circuit board or sheet.

10. A circuit unit as set forth in claim 6, wherein each of said switch pads comprises a diaphragm pad formed of a suitable metal material such as copper.