Flush lighted flat keyboard assembly

• US 4,163,138 A
• Filed: 03/17/1978
• Issued: 07/31/1979
• Est. Priority Date: 03/17/1978
• Status: Expired due to Term

• Current Assignee: Bowmar Instrument Corp. (Microchip Technology Incorporated)
• Original Assignee: Bowmar Instrument Corp. (Microchip Technology Incorporated)
• Inventors: Harden, Phillip L.
• Primary Examiner(s): Ross, Herbert F.
• Application Number:
  US05/887,742
• Time in Patent Office: 501 Days
• Field of Search: 200/308, 200/310, 200/317, 200/5 A
• US Class Current: 200/310
• 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 2205/026 Adhesive sheet
• CPC Class Codes: H01H 2209/006 Force isolators
• CPC Class Codes: H01H 2219/016 programmable
• CPC Class Codes: H01H 2219/044 Edge lighting of layer
• CPC Class Codes: H01H 2219/0622 only an illuminated ring around keys
• CPC Class Codes: H01H 2221/002 integral with membrane
• CPC Class Codes: H01H 2221/07 transparent

Abstract

A flush lighted flat keyboard assembly including a printed circuit board having conductors on one side. Resilient dome switch elements are supported on the one side of the board in spaced-apart relationship in peripheral contact with certain conductors to make center contact with other conductors upon the application of force thereon. Another printed circuit board has one side in facing relationship with the first board and has openings therein respectively in alignment with the switch elements. Light sources are mounted on the other side of the second board which has conductors thereon connected to energize the light sources. A flexible switch-actuating member has one side in facing relationship with the other side of the second board and has switch-actuating projections extending therefrom through the second board openings toward the switch elements. The one side of the actuating member also has isolator projections thereon intermediate the switch-actuating projections, which extend toward the second board. A flexible, flat keyboard member has one side abutting the other side of the actuator member. The actuator member is formed of light-transmissive material and selected areas of the keyboard member are light-transmissive so as to be selectively illuminated by the light sources.

Claims

1. In a flat keyboard assembly comprising a support member having flat opposite sides, at least two spaced switches on one side of said support member each including a resilient, metallic momentary-contact switch element selectively actuatable from a first to a second position in response to force exerted thereon, a flexible switch actuator member having flat opposite sides with one side thereof in spaced facing relationship with said one side of said support member and said switch elements, said one side of said actuator member having at least two switch-actuating projections thereon respectively extending toward and in alignment with said switch elements, and a flexible keyboard member having flat opposite sides, one side of said keyboard member abutting the other side of said actuator member whereby force exerted on said keyboard member in general alignment with a said switch element deflects said keyboard member and actuator member thereby causing a said projection to apply actuating force on the respective switch element, a light source;

means for mounting said light source adjacent said one side of said actuator member in the space between said switches and said one side of said actuator member and between said projections;

conductors connected to said light source for energizing the same;

said actuator member being formed of light-transmissive material, at least one selected area of said keyboard member being light-transmissive thereby being illuminated by said light source; and

means for maintaining said support member and keyboard member in assembled relation.

2. The assembly of claim 1 wherein said light source comprises a matrix of selectively energizable light-emitting elements thereby to provide an alpha-numeric display.

3. The assembly of claim 1 wherein said keyboard member has an opaque area surrounding said light-transmissive area, said light-transmissive area defining a selected indicia.

4. The assembly of claim 1 wherein said mounting means comprises another support member positioned between said first-named support member and said actuator member, said other support member having first and second flat opposite sides respectively facing and spaced from said one side of said first support member and said switch elements, and said one side of said actuator member, said other support member having at least two spaced openings formed therethrough, said switch-actuating projections respectively extending through said openings;

said light source being mounted on said second side of said other support member;

said conductors being on one side of said other support member.

5. The assembly of claim 4 wherein there is at least one light source adjacent each said other support member opening.

6. The assembly of claim 4 wherein there are at least two of said light sources respectively on opposite sides of each said other support member opening.

7. The assembly of claim 4 wherein there is a first group of a plurality of said light sources disposed in a line on one side of said other support member opening and a second group of a plurality of said light sources disposed in a line on the other side of said opening, said lines being parallel.

8. The assembly of claim 4 wherein said one side of said actuator member has at least one isolator projection intermediate said switch-actuating projections and extending toward said second side of said other support member whereby force exerted on said keyboard member in general alignment with one of said switch elements is isolated from other switch elements, there being at least two said light sources respectively intermediate said isolator projection and said switch-actuating projections.

9. The assembly of claim 4 wherein said support members are formed of rigid material.

10. The assembly of claim 4 further comprising a third member having first and second flat opposite sides, said first side of said third member abutting said second side of said other support member, said second side of said third member being spaced from said one side of said actuator member, said third member having at least two openings therethrough respectively aligned with said other support member openings and having said switch-actuating projections respectively extending therethrough, said third member having at least one cavity formed in said first side thereof with said light source being disposed therein, said third member being formed of light-transmissive material.

11. The assembly of claim 10 wherein said other support member and third member form a rigid sub-assembly, said first-named support member being formed of rigid material.

12. The assembly of claim 10 wherein there are a plurality of cavities formed in said first side of said third member surrounding each said opening, there being a plurality of said light sources respectively disposed in said cavities.

13. The assembly of claim 1 wherein said mounting means includes an opening therein, said light source being disposed in said opening, said conductors being on the other side of said support member.

14. The assembly of claim 13 further comprising another support member positioned between said first-named support member and said actuator member, said other support member having first and second opposite sides with said first side facing and spaced from said one side of said actuator member and said second side abutting said one side of said first-named support member, said second side of said other support member having cavities therein respectively accommodating said switch elements, said other support member having at least two openings formed therethrough respectively communicating with said cavities, said switch-actuating projections respectively extending through said openings, said other support member having another opening formed therein aligned with and communicating with said opening in said first-named support member, said light source extending into said other opening.

15. The assembly of claim 14 wherein said other opening is a cavity formed in said second side of said other support member, said other support member being formed of light-transmissive material.