Claims
- 1. In a luminaire comprising a reflector of substantially transparent material and means for mounting a light source within said reflector, the reflector having a prismatic outer surface that has many double-reflecting prisms located at juxtaposed spaced locations along said outer surface, the individual prisms being characterized by having two reflecting surfaces that are disposed so that a large percentage of the rays from said source entering the individual prisms strike said reflecting surfaces at angles of incidence greater than the critical angle of incidence, thereby totally internally reflecting a large percentage of said light from said source, the improvement comprising:
- means for controlling the amount of light passing from said source through said prismatic outer surface comprising an additive in particle form dispersed at least partially randomly within said transparent reflector material and serving to divert some of the light rays from said source into paths that intersect said reflecting surfaces at angles less than said critical angle of incidence, thereby causing said diverted rays to pass through said prismatic outer surface.
- 2. A luminaire as defined in claim 1 and further comprising:
- (a) a cover of substantially transparent material for the reflector located externally of said prismatic outer surface and of a shape generally conforming to that of said reflector, and
- (b) means for mounting said transparent cover closely adjacent the prismatic outer surface of said reflector in such a manner that said cover is spaced from said prismatic outer surface at substantially all points on the prism reflecting surfaces where said prism reflecting surfaces are disposed to effect total internal reflection of the light source rays.
- 3. The combination of claim 2 in which the reflecting surfaces of each prism meet at an apex and said transparent cover engages said prisms only at the apices thereof.
- 4. A luminaire as defined in claim 1 in which the individual prisms are further characterized by having their reflecting surfaces oriented so that most of the light rays from said source entering a prism strike the reflecting surfaces at angles of incidence greater than the critical angle of incidence, thereby totally internally reflecting most of the light from said source entering the prism.
- 5. A luminaire as defined in claim 1 in which such double-reflecting prisms are further characterized by being right-angle prisms.
- 6. A luminaire as defined in claim 1 in which said substantially transparent material is a plastic material.
- 7. A luminaire as defined in claim 1 in which said substantially transparent material is a plastic material selected from the group consisting of the following resins: acrylic, polystyrene, polycarbonate, polyethylene and butyrate.
- 8. A luminaire as defined in claim 1 in which said substantially transparent material is a plastic material and said additive comprises a material having an index of refraction different enough from that of the plastic reflector material to divert light rays through said reflector material by at least three degrees when said rays encounter said additive.
- 9. A luminaire as defined in claim 8 in which said additive comprises glass beads.
- 10. A luminaire as defined in claim 1 in which said additive comprises particles of light-reflective material.
- 11. A method of controlling the amount of light from a light source passing through the prismatic outer surface of a reflector of substantially transparent solid material that is adapted to surround said source, the prismatic outer surface having many double-reflecting prisms at juxtaposed spaced locations along said outer surface, the individual prisms being characterized by having two reflecting surfaces that are disposed so that a large percentage of the rays from said source entering a prism strike said reflecting surfaces at angles of incidence greater than the critical angle of incidence, thereby totally internally reflecting a large percentage of the light from said source, the reflector being formed from a material that is initially in a miscible state, said method comprising:
- (a) adding to said reflector material while in its miscible state solid particles, and
- (b) dispersing said particles throughout said miscible-state material so that when said material is solidified to form said reflector, said dispersed particles serve to divert light rays from said source into paths that intersect said reflecting surfaces at angles less than said critical angle of incidence, thereby causing said diverted rays to pass through said prismatic outer surface and produce uplight.
- 12. The method of claim 11 in which said substantially transparent material is a plastic material.
- 13. The method of claim 11 in which said substantially transparent material is a plastic material selected from the groups consisting of the following resins: acrylic, polystyrene, polycarbonate, polyethylene, and butyrate.
- 14. The method of claim 11 in which said substantially transparent material is a plastic material and said additive is a material having an index of refraction different enough from that of the plastic reflector material to divert light rays through said reflector material by at least three degrees when said rays encounter said additive.
- 15. The method of claim 14 in which said additive comprises glass beads.
- 16. A method as defined in claim 11 in which the uplighting as a percentage the lumen output of the luminaire is controlled as a direct function of the percentage of solid particles included in the reflector material.
- 17. In a luminaire comprising a reflector of substantially transparent material and means for mounting a light source within said reflector, the reflector having a prismatic outer surface that has many double-reflecting prisms located at juxtaposed spaced locations along said outer surface, the individual prisms being characterized by having two reflecting surfaces that are disposed so that a large percentage of the rays from said source entering the individual prisms strike said reflecting surfaces at angles of incidence greater than the critical angle of incidence, thereby totally internally reflecting a large percentage of said light from said source, the improvement comprising:
- means for controlling the amount of light transmitted through said prismatic outer surface comprising an additive in particle form dispersed within said transparent reflector material and serving to divert some of the light rays from said source into paths that intersect said reflecting surfaces at angles less than the critical angle of incidence, thereby causing said diverted rays to pass through said prismatic outer surface;
- a cover of substantially transparent material disposed about the reflector and located externally of said prismatic outer surface; and,
- wherein the reflecting surfaces of each prism meet at an apex and said transparent cover engages said prisms only at the apices thereof.
- 18. A luminaire as claimed in claim 17 wherein said reflector and said cover have respective annularly formed neck portions which are sized in a complimentary manner such that the annular neck portion of said cover fits about said annular neck portion of said reflector in a sealed manner.
- 19. A luminaire as claimed in claim 18 further comprising filter means disposed on said cover and effective for filtering air flow that may occur between atmosphere and an air space formed between said cover and said reflector.
- 20. A luminaire as claimed in claim 19 wherein said air space is formed between said cover and said reflector by said cover contacting only said apices formed when said reflecting surfaces of each prism meet thereby leaving a space between said cover and all points on said reflector that are below said apices.
CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation-in-part of co-pending application Ser. No. 281,117 - Osteen et al, filed on Dec. 7, 1988 now U.S. Pat. No. 4,903,180, and to the assignee of the present invention which application is incorporated by reference into the present application.
US Referenced Citations (11)
Continuation in Parts (1)
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Number |
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281117 |
Dec 1988 |
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