Fully illuminated backlit membrane touch switch

• US 4,262,182 A
• Filed: 01/11/1980
• Issued: 04/14/1981
• Est. Priority Date: 01/11/1980
• Status: Expired due to Term

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Schwehr, Gregory D., Basler, Peter H.
• Primary Examiner(s): Shepperd, John W.
• Application Number:
  US06/111,156
• Time in Patent Office: 459 Days
• Field of Search: 200/5 A, 200/159 B, 200/310, 200/314, 200/317, 200/311
• US Class Current: 200/314
• CPC Class Codes: H01H 13/83 characterised by legends, e.g. Braille, liquid crystal displays, light emitting or optical elements

Abstract

A printed wire board has lamp socket holes and switch contact pairs adjacent the holes on the top surface of the board and lamp socket contacts adjacent the holes on its bottom surface. An insulating spacer sheet is adhered to the board and has apertures which are congruent with the switch contact pairs. A membrane, adhered to the top surface of the spacer, has lamp holes and short circuiting contacts on its bottom surface for being flexed through the apertures to bridge gaps between the contact pairs on the board. An apertured rigid plate is superposed over and spaced from the membrane. Combination light channel and switch operating plunger elements fit in the plate apertures and contact the membrane. A film on which switch operating touch zones are delineated is adhered to the plate.

Claims

1. A backlit membrane touch switch panel comprising:

an insulating board having a hole for receiving a light source and having a pair of contacts with a gap between them disposed on the nominally top surface of said board adjacent said hole,

a thin insulating spacer sheet arranged with its bottom surface facing said board, said spacer sheet having an aperture aligned with said contacts,

an insulating flexible membrane having a hole aligned substantially with the hole in said board and arranged with its bottom surface facing the top surface of said spacer sheet, said membrane having a thin contact disposed on its bottom surface and aligned with said spacer aperture, said contact becoming engageable with said pair of contacts to bridge said gap when said membrane is pressed and flexed through said aperture, said membrane restoring to its unflexed condition when it is not pressed,

a rigid plate member arranged with its bottom surface in substantial parallelism with said membrane and spaced from said membrane, said plate member having an aperture that aligns substantially with said aperture in said spacer sheet,

means for maintaining said plate member at a fixed spacing from said membrane,

a rigid combination switch plunger and light channel element having its nominally upper end loosely fit in said plate aperture and its lower end bearing on said membrane in the vicinity of the contact on its bottom,

a film having its bottom surface interfaced with the top surface of said plate member and having a translucent zone disposed over said plunger and light channel element such that force produced by touching said zone will be transmitted by said element to flex said membrane and cause said contacts to engage, and

a lamp and a socket for the lamp, said socket having exposed contacts extending from it and leading to said lamp, said socket having means for interlocking it with said board and said socket holding lamp for it to extend into said combination light channel and plunger element, said exposed socket contacts engaging respectively with said contacts on the bottom surface of the board when said socket is interlocked.

2. The touch switch panel as in claim 1 wherein:

said combination plunger and light channel element is a hollow element having a bottom end opening bearing on the nominally top surface of said membrane and having a top end opening extending into the aperture of said plate member, and

a light diffuser disposed over one of said end openings.

3. The touch switch panel as in claim 1 wherein:

said combination plunger and light channel element is a prism of light conductive material having nominally bottom, top and side surfaces, said bottom surface bearing on the top surface of said membrane and said top surface extending into the aperture of said plate member, said side surfaces being opaque and said bottom surface having a cavity for receiving a light source.

4. The touch switch panel as in claim 1 wherein:

each contact in the pair of contacts on said top surface of said board comprises a plurality of thin conductive strips and the strips of one contact are interdigitated with the strips on the other but have insulating gaps between them.

5. The touch switch panel as in any of claims 1, 2, 3 or 4 including:

thin pairs of contacts with a gap between them disposed on the nominally bottom surface of said board and arranged adjacent said hole in said board.