Directional backlighting for display panels
First Claim
Patent Images
1. A backlight system for a display panel, the backlight system comprising:
- a wedge-shaped light guide comprising a thin end opposite a thick end, the thick end of the wedge-shaped light guide comprising a cylindrical reflector with a plurality of reflecting facets, the cylindrical reflector being curved along a first direction extending between and connecting two opposing major faces at the thick end of the wedge-shaped light guide, and uncurved along a second direction extending between and connecting two opposing minor faces at the thick end of the wedge-shaped light guide;
a plurality of light sources of first and second subsets arranged along the thin end of the wedge-shaped light guide, opposite the cylindrical reflector, wherein each light source of the first subset is configured to output light of a narrower emitter angle, and each light source of the second subset is configured to output light of a wider emitter angle, and wherein the light sources of the first subset and the light sources of the second subset are arranged in an alternating relation along the thin end of the wedge-shaped light guide; and
a controller configured to switch between operating the backlight system in a narrow angle mode in which the first subset of light sources are in an on state and the second subset of light sources are in an off state, and operating the backlight system in a wide angle mode in which the second subset of light sources are in an on state.
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Abstract
Various embodiments are disclosed that relate to display panel backlight systems that output light with a narrower angular intensity distribution than a diffuse backlight. For example, one disclosed embodiment provides a backlight system comprising a wedge-shaped light guide comprising a thin end and a thick end, the thick end of the wedge-shaped light guide comprising a linear reflector with plurality of facets, and wherein the backlight system also comprises a plurality of light sources arranged along the thin end of the wedge-shaped light guide.
382 Citations
17 Claims
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1. A backlight system for a display panel, the backlight system comprising:
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a wedge-shaped light guide comprising a thin end opposite a thick end, the thick end of the wedge-shaped light guide comprising a cylindrical reflector with a plurality of reflecting facets, the cylindrical reflector being curved along a first direction extending between and connecting two opposing major faces at the thick end of the wedge-shaped light guide, and uncurved along a second direction extending between and connecting two opposing minor faces at the thick end of the wedge-shaped light guide; a plurality of light sources of first and second subsets arranged along the thin end of the wedge-shaped light guide, opposite the cylindrical reflector, wherein each light source of the first subset is configured to output light of a narrower emitter angle, and each light source of the second subset is configured to output light of a wider emitter angle, and wherein the light sources of the first subset and the light sources of the second subset are arranged in an alternating relation along the thin end of the wedge-shaped light guide; and a controller configured to switch between operating the backlight system in a narrow angle mode in which the first subset of light sources are in an on state and the second subset of light sources are in an off state, and operating the backlight system in a wide angle mode in which the second subset of light sources are in an on state. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A display device, comprising:
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a modulating image display panel; and a backlight system configured to backlight the modulating image display panel, the backlight system comprising; a substantially wedge-shaped light guide comprising two opposing major faces extending between a thin end and a thick end of the substantially wedge-shaped light guide, the thick end comprising a cylindrical reflector with a plurality of facets, the cylindrical reflector being curved along a first direction extending between and connecting the two opposing major faces and uncurved in a second direction extending between and connecting two opposing minor faces of the wedge-shaped light guide; a plurality of light sources arranged along the thin end of the backlight system and configured to be illuminated together, the plurality of light sources comprising alternating narrow-angle light sources configured to output light of a narrower emitter angle and wide-angle light sources configured to output light of a wider emitter angle; a controller configured to switch between operating the backlight system in a narrow angle mode in which the narrow-angle light sources are in an on state and the wide-angle light sources are in an off state, and operating the backlight system in a wide angle mode in which the wide-angle light sources are in an on state; and a turning structure disposed on an exit surface of the light guide to redirect light emitted from the exit surface, the turning structure comprising a plurality of facets, with a thickness between the two opposing major faces varying as a function of distance across the light guide to provide a flat power distribution of the light exiting the backlight system. - View Dependent Claims (13, 14, 15)
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16. A method of operating a backlit display device, comprising:
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illuminating a first plurality of light sources to inject light into a thin end of a wedge-shaped light guide at a plurality of locations arranged in an alternating relation with a second plurality of light sources along the thin end of the wedge-shaped light guide; internally reflecting the light via a cylindrical reflector disposed at a thick end of the wedge-shaped light guide opposite the thin end where the first plurality of light sources inject light, the cylindrical reflector being curved along a first direction extending between and connecting two opposing major faces at the thick end of the wedge-shaped light guide and uncurved along a second dimension extending between and connecting two opposing minor faces of the wedge-shaped light guide; emitting the light from the wedge-shaped light guide; directing the light emitted from the wedge-shaped light guide through a modulating display panel to produce a displayed image; pursuant to a triggering event, operating the backlit display device in a wide angle mode in which the first plurality of light sources are off and the second plurality of light sources are on, where light from each of the second plurality of light sources is injected to the wedge-shaped light guide with a wider angular intensity distribution than light from each of the first plurality of light sources. - View Dependent Claims (17)
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Specification