ENCAPSULATED SOLID STATE LIGHT EMITTING DEVICE

• US 3,821,590 A
• Filed: 02/24/1972
• Issued: 06/28/1974
• Est. Priority Date: 03/29/1971
• Status: Expired due to Term

• Current Assignee: Boivin L, Kosman K
• Original Assignee: Boivin L, Kosman K
• Inventors: KOSMAN K, BOIVIN L
• Application Number:
  US05/229,140
• Time in Patent Office: 855 Days
• US Class Current: 313/499
• CPC Class Codes: H01L 33/54 having a particular shape
• CPC Class Codes: H01L 33/60 Reflective elements
• CPC Class Codes: H05B 33/04 Sealing arrangements , e.g. against humidity
• CPC Class Codes: H05B 33/20 characterised by the chemical or physical composition or the arrangement of the material in which the electroluminescent material is embedded
• CPC Class Codes: H05B 33/22 characterised by the chemical or physical composition or the arrangement of auxiliary dielectric or reflective layers
• CPC Class Codes: Y10S 362/80 Light emitting diode

Abstract

A light emitting device containing an encapsulated light emitting diode, in which the light from the diode is collimated by a reflector and in which the front face of the encapsulated diode is formed with a plurality of lenses which disperse the collimated light. The device can be viewed over a wide angle, for example + OR - 45*, without a readily apparent reduction in brilliance or size. An optical filter-for increased contrast for example-can be used. More than one diode can be positioned in a device. Variation in the form of the lenses provides increased luminous intensity for particular viewing angles and by accepting some loss in effectiveness, for example some sectoring, the viewing angle can be increased up to approximately + OR - 90*.

Claims

1. A solid state light emitting device for producing widely diffused light, comprising:

- a body of transparent insulating material having a front surface and a rear surface, said front surface having formed thereon a polylenticular lens formation and said rear surface having formed thereon a parabolic light reflecting surface;

a semiconductor light emitting diode mounted within said body of transparent insulating material in engagement with and at the focus of said parabolic reflecting surface, said reflecting surface being formed of electrically conducting material and forming one electrical lead to said diode, said diode emitting light laterally toward said reflecting surface and said reflecting surface reflecting said light toward said front surface to issue through said front surface, said polylenticular lens formation comprising a central cavity and a plurality of spherical cavities surrounding said central cavity, said cavities dispersing said light issuing through said front surface.

2. A device as claimed in claim 1, wherein said central cavity is of concial form, the apex of the conical form extending inward toward the semiconductor element and having an included angle such that the light incident on the central recess from the semiconductor element is reflected outwards towards the reflector.

3. A device as claimed in claim 1, said front surface being of convex form, and an internal reflector positioned between said light emitting diode and said front surface, the internal reflector being of conical formation with its apex toward said light emitting diode and its base at said front surface, said polylenticular lens formation comprising a plurality of annular lens formations extending around the base of the internal reflector, the internal reflector arranged to deflect light outward through said lens formation.

4. A device as claimed in claim 3, the internal reflector comprising a plurality of conical sections in sequence, the section nearest said light emitting diode being of largest included angle with each succeeding section being of a smaller included angle.