Lighting apparatus having low profile
AssigneeTeledyne Lighting and Display Products, Inc.
InventorsDavid G. Pelka, John Popovich, Yong Qiao
Life of this patent
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Abstract
Disclosed is a low profile lighting apparatus that is particularly advantageous for use as a backlight for illuminating a display. The lighting apparatus includes a waveguide coupled to a light source for injecting light into the waveguide. The waveguide includes a plurality of elongate structures for ejecting light propagating within the waveguide through a predetermined surface of the waveguide. Another embodiment of the waveguide includes a central region of reduced thickness that redirects light propagating within the waveguide. The lighting apparatus has a low profile so it is particularly useful in areas of limited space.
Claims14
A lighting apparatus, comprising:
- a device that emits light;
- an optical cavity formed by diffusive reflective surfaces, said cavity having an output region through which light from said cavity passes;
- said light emitting device being mounted to supply light to said cavity while being hidden from direct view through said output region, said cavity having a diffusely reflective surface area and said output region having an area, the ratio of said area of said output region to the sum of (i) said area of said output region and (ii) said surface area of said cavity being at least 0.05, said cavity having a depth and said output region having an edge-to-edge bisector dimension, the ratio of said depth to said bisector dimension being significantly less than 0.1;
- and
- an angular spectrum restrictor positioned to restrict output illumination through said output region to a predetermined range of angles.
A method of lighting, comprising:
- producing illumination from an optical cavity formed by diffusely reflecting surfaces and outputting illumination from the cavity through an output illumination region, said producing of said illumination comprising directing light rays from a source of illumination into the cavity such that the source of the illumination is not visible through the output illumination region;
- restricting the angular spectrum of illumination from the output illumination region to a predetermined range of angles;
- said restricting comprising using a brightness enhancing film to concentrate light passing from the cavity through the output illumination region;
- and
- mounting the optical cavity to illuminate at least a portion of a room.
Dependencies are inferred from the claim text.