Keyboard of a membrane contact type

• US 4,837,412 A
• Filed: 06/20/1988
• Issued: 06/06/1989
• Est. Priority Date: 06/29/1987
• Status: Expired due to Fees

• Current Assignee: OKI Electric Industry Company Limited
• Original Assignee: OKI Electric Industry Company Limited
• Inventors: Tachibana, Sadao
• Primary Examiner(s): Scott, J. R.
• Application Number:
  US07/208,721
• Time in Patent Office: 351 Days
• Field of Search: 200/5 R, 200/5 A, 200/6 A, 200/159 B, 200/292, 200/DIG. 1, 361/398, 400/479-479.2
• US Class Current: 200/5.00A
• CPC Class Codes: H01H 13/702 with contacts carried by or formed from layers in a multilayer structure, e.g. membrane switches
• CPC Class Codes: H01H 2207/004 Printed circuit tail
• CPC Class Codes: H01H 2229/038 Folding of flexible printed circuit
• CPC Class Codes: H05K 1/0393 Flexible materials H05K1/038 takes precedence; specific organic compositions are classified in H05K1/0313 and subgroups
• CPC Class Codes: H05K 1/118 specially for flexible printed circuits, e.g. using folded portions
• CPC Class Codes: H05K 2201/055 Folded back on itself
• CPC Class Codes: H05K 2201/09063 Holes or slots in insulating substrate not used for electrical connections
• CPC Class Codes: H05K 2201/09081 Tongue or tail integrated in planar structure, e.g. obtained by cutting from the planar structure
• CPC Class Codes: H05K 2201/09445 Pads for connections not located at the edge of the PCB, e.g. for flexible circuits
• CPC Class Codes: H05K 3/365 by abutting, i.e. without alloying process

Abstract

A keyboard of a membrane contact type comprises a membrane contact unit having movable contacts, fixed contacts disposed respectively opposite to the movable contacts, and a printed wiring board having electronic circuit elements and provided with printed wiring lines. The membrane contact unit comprises a flexible, insulating, membranous substrate having movable contacts formed in a movable contact section and fixed contacts formed in a fixed contact section demarcated by a folding line, in the same surface as the movable contacts and arranged symmetrically about the folding line. First and second wiring lines connect the movable contacts and the fixed contacts respectively in a predetermined connecting pattern. A first terminal section having first terminals is connected respectively to the first wiring lines, and a second terminal section having second terminals is connected respectively to the second wiring lines. The first and second terminal sections are formed near the folding line. U-shaped slits are formed in the substrate so as to embrace the extremities of the first and second terminal sections, respectively, so that the first and second terminal sections project from the folded edge of the membranous substrate when the same is folded along the folding line to facilitate electrically and mechanically connecting the membrane contact unit to the printed wiring board.

Claims

1. A keyboard of a membrane contact type comprising:

(a) a membrane contact unit comprising;

a flexible, insulating, membranous substrate having a movable contact section and a fixed contact section demarcated by a folding line, and folded along said folding line,

a plurality of movable contacts formed on one surface of said flexible, insulating, membranous substrate in said movable contact section and divided into a plurality of lateral lines,

a plurality of fixed contacts formed on the same surface as said movable contacts in said fixed contact section and divided into a plurality of longitudinal rows,

first wiring lines formed in said movable contact section and each connecting the movable contact on each lateral line in series,

second wiring lines formed in said fixed contact section and each connecting the fixed contact on each longitudinal row in series,

a first terminal section having a plurality of first terminals respectively connected to said first wiring lines, and formed in the vicinity of said folding line,

a second terminal section having a plurality of second terminals respectively connected to said second wiring lines, and formed in the vicinity of said folding line,

a spacer having openings and placed between said movable contact section and said fixed contact section so that said openings are aligned respectively with said movable contacts and the corresponding fixed contacts; and

(b) a printed wiring board having electronic circuit elements and provided with printed wiring pattern and terminals connected to said plurality of first and second terminals of said membrane contact unit.

2. A keyboard of a membrane contact type, according to claim 1, wherein a first U-shaped slit is formed in the vicinity of said folding line so as to embrace the extremity of said first terminal section, and a second U-shaped slit is formed in the vicinity of said folding line so as to embrace the extremity of said second terminal section.

3. A keyboard of a membrane contact type, according to claim 2, wherein said extremities of said first and . second terminal sections project from the folded edge of said membrane contact unit by said first and second U-shaped slits respectively, for connection to said terminals of said printed wiring board when said flexible, insulating, membranous substrate is folded along said folding line.