High aspect ratio lighting element

• US 5,190,370 A
• Filed: 08/21/1991
• Issued: 03/02/1993
• Est. Priority Date: 08/21/1991
• Status: Expired due to Term

• Current Assignee: 3M Company
• Original Assignee: 3M Company
• Inventors: Cobb, Sanford Jr., Miller, Richard A., Aho, Kenneth A.
• Primary Examiner(s): Cole, Richard R.
• Application Number:
  US07/748,030
• Time in Patent Office: 559 Days
• Field of Search: 362/31, 362/237, 362/244, 362/268, 362/309, 362/340, 362/339
• US Class Current: 362/340
• CPC Class Codes: F21S 43/239 plate-shaped
• CPC Class Codes: F21S 43/245 emitting light from one or more of its major surfaces
• CPC Class Codes: F21S 43/247 with a single light source being coupled into the light guide
• CPC Class Codes: F21S 43/249 with two or more light sources being coupled into the light guide
• CPC Class Codes: F21S 43/26 Refractors, transparent cover plates, light guides or filters not provided in groups F21S43/235 - F21S43/255
• CPC Class Codes: F21V 7/00 Reflectors for light sources characterised by cooling arrangements F21V29/505
• CPC Class Codes: G02B 6/002 by shaping at least a portion of the light guide, e.g. with collimating, focussing or diverging surfaces
• CPC Class Codes: G02B 6/0031 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0038 Linear indentations or grooves, e.g. arc-shaped grooves or meandering grooves, extending over the full length or width of the light guide
• CPC Class Codes: G02B 6/0046 Tapered light guide, e.g. wedge-shaped light guide
• CPC Class Codes: G02B 6/0055 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0071 with elongated shape, e.g. tube
• CPC Class Codes: G02B 6/0096 the lights guides being of the hollow type
• CPC Class Codes: G02F 1/133615 Edge-illuminating devices, i.e. illuminating from the side

Abstract

A lighting element has a light source positioned so as to provide a beam of light at a grazing angle to a light extractor. The extractor has a plurality linear triangular prism on the side struck by the beam of light. The prisms lie in a smooth arcuate curve.

Claims

1. A lighting element comprising:

a housing defining an optical cavity having an optical window;

a light extractor for directing light out of said optical cavity through said optical window, said light extractor having a first side and a second side, said second side having a plurality of linear triangular prisms thereon, each of said prisms having first and second facets, said prisms defining a smooth arcuate curve; and

a light source positioned so as to provide a beam of light traveling at a grazing angle to said second surface of said extractor and approaching said extractor from a first end thereof such that said light will enter each of said prisms through said prism'"'"'s first facet, be totally internally reflected by said prism'"'"'s second facet and emerge from said extractor through said first side;

wherein said curve is designed to provide collimated output from said lighting element.

2. A lighting element comprising:

a housing defining an optical cavity having an optical window;

a light extractor for directing light out of said optical cavity through said optical window, said light extractor having a first side and a second side, said second side having a plurality of linear triangular prisms thereon, each of said prisms having first and second facets, said prisms defining a smooth arcuate curve; and

a light source positioned so as to provide a beam of light traveling at a grazing angle to said second surface of said extractor and approaching said extractor from a first end thereof such that said light will enter each of said prisms through said prism'"'"'s first fact, be totally internally reflected by said prism'"'"'s second facet and emerge from said extractor through said first side, said light source comprising

a second light extractor for directing light toward said first light extractor, said second light extractor having a first side and a second side, said second side having a plurality of linear triangular prisms thereon, each of said prisms having first and second facets, said prisms defining a smooth arcuate curve; and

a second light source positioned so as to provide a beam of light traveling at a grazing angle to said second surface of said second extractor and approaching said second extractor from a first end thereof such that said light will enter each of said prisms through said prism'"'"'s first facet, be totally internally reflected by said prism'"'"'s second facet and emerge from said second extractor through said first side.

3. The lighting element of claim 2 wherein each of said curves is designed to provide collimated output from said fixture.

4. The lighting element of claim 2 wherein each of said curves is designed to provide uniform light output.

5. A lighting element comprising:

a housing defining an optical cavity having an optical window;

a light extractor for directing light out of said optical cavity through said optical window, said light extractor having a first side and a second side, said second side having a plurality of linear triangular prisms thereon, each of said prisms having first and second facets;

a first light source positioned so as to provide a beam of light traveling at a grazing angle to said second surface of said extractor and approaching said extractor from a first end thereof such that said light will enter each of said prisms through said prism'"'"'s first facet, be totally internally reflected by said prism'"'"'s second facet and emerge from said extractor through said first side; and

a second source positioned so as to provide a beam of light traveling at a grazing angle to said second surface of said extractor and approaching said extractor from a second end thereof opposite said first end such that said light will enter each of said prisms through said prism'"'"'s second facet, be totally internally reflected by said prism'"'"'s first facet and emerge from said extractor through said first side.

6. A lighting element according to claim 5 wherein said curve is designed to provide collimated output from said fixture.