Light emissive diode displays

• US 4,007,396 A
• Filed: 11/03/1975
• Issued: 02/08/1977
• Est. Priority Date: 11/06/1974
• Status: Expired due to Term

• Current Assignee: Marconi Holdings Company Limited
• Original Assignee: Marconi Holdings Company Limited
• Inventors: Kimber, Paul Kevin, Wisbey, Philip Henry
• Primary Examiner(s): Krawczewicz, Stanley T.
• Application Number:
  US05/628,224
• Time in Patent Office: 463 Days
• Field of Search: 13/500, 13/111, 13/112, 13/113, 357/17, 350/156, 350/157
• US Class Current: 313/500
• CPC Class Codes: G09F 13/22 electroluminescent electroluminescent light sources per se H05B33/00
• CPC Class Codes: G09F 2013/222 with LEDs
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 33/60 Reflective elements

Abstract

An LED display is provided with a reflective surface over those parts of the display which do not themselves emit light. This enables a polarizer to be used to enhance the display contrast under conditions of bright ambient light.

Claims

1. A light emissive diode display comprising, in combination:

a base having a plurality of light emissive diodes carried thereby;

a mirror finished conductive layer covering most of the area surrounding said light emissive diodes; and

circular polarizer means overlying said base for allowing light emitted by said diodes to pass therethrough for viewing;

said conductive layer having the characteristic of reversing the handedness of light reflected therefrom whereby light passing through said circular polarizer means and having one handedness imparted thereto will upon reflection by said conductive layer have a handedness opposite to said one handedness such that the reflected light will not pass back through the circular polarizer means.

2. A light emissive diode display as defined in claim 1 wherein said conductive layer is copper.

3. A light emissive diode display as defined in claim 1 wherein said conductive layer is aluminum.

4. A light emissive diode display as defined in claim 1 including conductor means for establishing electrical connections to said diodes, said conductive layer forming at least part of said conductor means.

5. A light emissive diode display as defined in claim 2 including conductor means for establishing electrical connections to said diodes, said conductive layer forming at least part of said conductor means.

6. A light emissive diode display as defined in claim 3 including conductor means for establishing electrical connections to said diodes, said conductive layer forming at least part of said conductor means.

7. A light emissive diode display as claimed in claim 6 wherein the conductive layer is formed on the underside of a transparent cover plate through which the display is viewed.

8. A light emissive diode display as claimed in claim 6 in which a glass encapsulation is provided for the light emissive diodes.