Illumination system for illuminating a display device

• US 7,950,830 B2
• Filed: 04/11/2007
• Issued: 05/31/2011
• Est. Priority Date: 04/13/2006
• Status: Expired due to Fees

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Kosters, Paulus G. H.
• Primary Examiner(s): Ward; John A
• Application Number:
  US12/296,346
• Publication Number:
  US 20090116220A1
• Time in Patent Office: 1,511 Days
• Field of Search: 362/97.1, 362/259, 362/297, 362/296.01, 362/296.02, 362/296.05, 362/296.07
• US Class Current: 362/296.07
• CPC Class Codes: F21V 7/09 with a combination of different curvatures
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: G02B 5/10 with curved faces

Abstract

An illumination system for illuminating a display device includes a conical reflector associated with the light source for illuminating a light-exit window. The reflector is arranged for reflecting light emitted by the light source towards the light-exit window and is radially segmented into a plurality of reflector-cone segments, each including at least one convex-cone segment being convex shaped in a lateral direction with respect to a source axis for lateral distribution of light emitted by the light source over the light-exit window.

Claims

1. An illumination system for illuminating a display device, the illumination system comprising:

a light source arranged on a source axis,

a light-exit window for emitting light generated by the light source, the light-exit window arranged substantially perpendicularly to the source axis and

a conical reflector associated with the light source and arranged around the source axis for reflecting light emitted by the light source towards the light-exit window, the reflector tapering from the light-exit window towards the light source and being radially segmented into a plurality of reflector-cone segments;

wherein the light-exit window has a polygonal shape and

wherein the plurality of reflector-cone segments comprises

a plurality of convex-cone segments, each convex-cone segment being convex-shaped in a lateral direction relative to the source axis and having a convex-segment axis intersecting with the source axis and arranged in a first imaginary plane defined by the source axis and intersecting an edge line of the light-exit window, the edge line connecting two neighboring corners of the polygonal shape of the light-exit window for lateral distribution of the light generated by the light source and emitted through the light-exit window, and

a plurality of concave-cone segments being concave shaped in lateral direction with respect to the source axis, each concave-cone segment having a concave-segment axis intersecting with the source axis and being arranged in a second imaginary plane defined by the source axis and a corner of the polygonal shape of the light-exit window.

2. An illumination system as claimed in claim 1, wherein each concave-cone segment is arranged between two convex-cone segments.

3. An illumination system as claimed in claim 1, wherein the reflector comprises a smooth reflecting surface comprising the reflector-cone segments.

4. An illumination system as claimed in claim 1, wherein at least one of the reflector-cone segments is convex shaped in radial direction with respect to the light-exit window.

5. An illumination system as claimed in claim 1, wherein the light source is a light emitting diode, or a laser diode, or a light emission window of an optical waveguide.

6. A backlight illumination system for illuminating a display device, the backlight illumination system comprising an array of the illumination systems as claimed in claim 1.

7. A backlight illumination system as claimed in claim 6, wherein the light-exit window of each illumination system has a substantially polygonal shape and wherein each illumination system comprises a reflector comprising a plurality of convex-cone segments, each convex-cone segment having a convex-segment axis intersecting with the source axis and arranged in a first imaginary plane defined by the source axis and intersecting an edge line of the light-exit window, the edge line connecting two neighboring corners of the polygonal shape of the light-exit window.

8. A backlight illumination system as claimed in claim 6, wherein the light-exit window of each illumination system has a substantially polygonal shape, a corner of at least one of the polygonal shapes being illuminated by a plurality of light sources of at least one illumination systems of the array of illumination systems, and wherein each illumination system comprises a reflector comprising a plurality of convex-cone segments, each convex-cone segment having a convex-segment axis intersecting with the source axis and arranged in a first imaginary plane, at least one first imaginary plane of at least one of the illumination systems being defined by the source axis and the corner of the polygonal shape of the light-exit window.

9. A display system comprising the backlight illumination system, as claimed in claim 6.