Flexible, high contrast, non-glare, polarizing filter for an illuminated switch assembly

• US 4,318,958 A
• Filed: 08/25/1980
• Issued: 03/09/1982
• Est. Priority Date: 03/19/1979
• Status: Expired due to Term

• Current Assignee: United States Of America As Represented By The Secretary Of The Army (Government of the United States of America)
• Original Assignee: The United States Of America As Represented By The Secretary Of The Army
• Inventors: Piatt, David M.
• Primary Examiner(s): Herbert, Jr., Thomas J.
• Application Number:
  US06/181,460
• Time in Patent Office: 561 Days
• Field of Search: 200/46, 200/313, 200/1 R, 200/5 R, 340/365 S, 428/215, 428/332, 428/426
• US Class Current: 428/332
• CPC Class Codes: G02B 27/281 used for attenuating light intensity, e.g. comprising rotatable polarising elements
• CPC Class Codes: Y10T 428/26 Web or sheet containing structurally defined element or component, the element or component having a specified physical dimension

Abstract

An optically coated, flexible glass plate cemented to a sheet of polarizingaterial combine to provide a high contrast, non-glare, polarizing filter that can be used in combination with an illuminated switch assembly such as with conventional membrane switches.

Claims

1. A filter for a membrane switch array having selectively illuminated indicia, the filter comprising:

(a) a flexible glass sheet of sufficient thinness to permit touch actuation of a selected individual membrane switch of said array, said sheet having its obverse surface coated with a non-glare coating having properties specifically adapted for use with glass,

(b) a flexible polarizer sheet of sufficient thinness for said touch actuation, and

(c) transparent bonding material joining the reverse side of said glass sheet to said polarizer sheet so that the resulting filter when associated with the switch substantially reduces glare and enhances contrast in the illuminated indicia.

2. The filter of claim 1 in which said polarizer is a circuit or polarizer.

3. The filter of claim 1 in which said polarizer has a thickness of up to 10 mils.

4. The filter of claim 1 in which said transparent bonding material is epoxy cement.

5. The filter of claim 1 in which said non-glare coating is a high efficiency, anti-reflective coating for glass having the properties of that known by the trade name HEA.