LIGHT GUIDE AND LIGHT-OUTPUT DEVICE

• US 20100046219A1
• Filed: 04/09/2008
• Published: 02/25/2010
• Est. Priority Date: 04/12/2007
• Status: Active Grant

• Current Assignee: Signify Holding B.V. (Signify N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Vissenberg, Michel Cornelis Josephus Marie, Willemsen, Oscar Hendrikus, Ijzerman, Willem Lubertus, Krijn, Marcellinus Petrus Carolus Michael, Cornelissen, Hugo Johan, Van Gorkom, Ramon Pascal, Pijlman, Fetze
• Granted Patent: US 8,414,162 B2
• Time in Patent Office: Days
• US Class Current: 362/235
• CPC Class Codes: F21W 2131/40 Lighting for industrial, commercial, recreational or military use
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: G02B 5/045 Prism arrays
• CPC Class Codes: G02B 6/0021 for housing at least a part of the light source, e.g. by forming holes or recesses
• CPC Class Codes: G02B 6/0036 2-D arrangement of prisms, protrusions, indentations or roughened surfaces
• CPC Class Codes: G02B 6/0053 Prismatic sheet or layer; Brightness enhancement element, sheet or layer
• CPC Class Codes: G02B 6/0055 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0068 Arrangements of plural sources, e.g. multi-colour light sources
• CPC Class Codes: G02B 6/0073 Light emitting diode [LED]

Abstract

A light guide (11; 101; 111) comprising first and second oppositely arranged faces, an in-coupling portion (13a-f) for in-coupling of light from a light-source (12a-f; 95a-f; 102; 106a-c; 112a-f), and an out-coupling portion (15a-f; 103; 113a-f) located adjacent to the in-coupling portion (13a-f). The out-coupling portion (15a-f; 103; 113a-f) is configured to out-couple a primary light beam having a direction of propagation directed from a position in the in-coupling portion (13a-f) with a lower out-coupling efficiency than a secondary light beam having a direction of propagation directed from a position in the light guide (11; 101; 111) outside the in-coupling portion (13a-f). In this manner, a good mixing of light in the light guide can be achieved without imposing any particular requirements on the collimation of the in-coupled light.

Claims

1. A light guide comprising

first and second oppositely arranged faces;

an in-coupling portion for in-coupling of light from a light-source; and

an out-coupling portion located adjacent to said in-coupling portion, wherein

said out-coupling portion is configured to out-couple a primary light beam having a direction of propagation directed from a position in said in-coupling portion with a lower out-coupling efficiency than a secondary light beam having a direction of propagation directed from a position in the light guide outside said in-coupling portion;

said out-coupling portion comprises a plurality of out-coupling structures, and

said out-coupling structures include a plurality of grooves formed on at least one of said first and second faces of the light guide, each of said grooves essentially extending along a projection of a respective one of said primary light beams in said face of the light guide in said out-coupling portion.

2. The light guide according to claim 1, further comprising redirecting means for redirecting said primary light beam, thereby converting said primary light beam into a secondary light beam.

3. The light guide according to claim 1, further comprising an in-coupling structure formed at said in-coupling portion.

4. The light guide according to claim 3, wherein said in-coupling structure comprises beam-shaping means for collimating said in-coupled light.

5. The light guide according to claim 3, wherein said in-coupling structure comprises a recess formed in said light guide from said first or second face.

6. The light guide according to claim 5, wherein said recess has a substantially rectangular cross-section in a plane parallel to said light guide, thereby enabling collimation of in-coupled light in a plane parallel with said light guide.

8. The light guide according to claim 1, comprising a plurality of collimating structures being aligned with a corresponding plurality of said out-coupling structures.

10. The light guide according to claim 1, further comprising a reflective layer arranged on one side thereof at least at said out-coupling portion.

11. The light guide according to claim 1, comprising a plurality of in-coupling portions, each being adapted to in-couple light from an associated light-source, and a plurality of out-coupling portions, each being adjacent to a corresponding one of said in-coupling portions and configured to out-couple a primary light beam having a direction of propagation directed from a position in said corresponding in-coupling portion with a lower out-coupling efficiency than a secondary light beam having a direction of propagation directed from a position in the light guide outside said corresponding in-coupling portion.

12. The light guide according to claim 11, further comprising at least one guiding portion located between neighboring out-coupling portions to prevent cross-talk therebetween.

13. The light guide according to claim 11, wherein said in-coupling portions are arranged in an array forming a rectangular grid pattern.

14. A light output device comprising a light guide according to claim 1 and at least one light-source arranged at said in-coupling portion.

15. A light-output device comprising a light-guide according to claim 11 having redirecting means arranged between adjacent out-coupling portions, said light-output device further comprising a plurality of light-sources each being arranged at a respective one of said in-coupling portions, wherein neighboring ones of said light-sources are adapted to emit differently colored light, thereby improving color uniformity of light output by said light-output device.

16. The light-output device according to claim 14, wherein the light-source comprises at least one light-emitting diode.

7. (canceled)

9. (canceled)