ILLUMINATION SURFACES WITH REDUCED LINEAR ARTIFACTS

• US 20100208469A1
• Filed: 02/10/2010
• Published: 08/19/2010
• Est. Priority Date: 02/10/2009
• Status: Abandoned Application

• Current Assignee: Oree, Inc.
• Original Assignee: Oree, Inc.
• Inventors: Shani, Yosi
• Application Number:
  US12/703,426
• Publication Number:
  US 20100208469A1
• Time in Patent Office: Days
• US Class Current: 362/322
• CPC Class Codes: G02B 6/0036 2-D arrangement of prisms, protrusions, indentations or roughened surfaces
• CPC Class Codes: G02B 6/0055 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0078 Side-by-side arrangements, e.g. for large area displays

Abstract

Illumination surfaces according to the present invention eliminate or at least reduce linear “stitch” artifacts at edges between tiled illumination devices. As a result, light of substantially uniform intensity is emitted across the entire illumination system. This is achieved, in various embodiments, by reflecting, through the gaps between adjacent light-guide elements, light directed through the bottom surfaces of the elements.

Claims

1. A planar illumination device comprising:

first and second light-guide elements each comprising an illumination surface, an opposed bottom surface, and a plurality of externally reflective side walls perpendicular to the illumination and bottom surfaces, the first and second light-guide elements being separated by a gap; and

at least one mirror in opposition to the bottom surfaces of the light-guide elements and underlying the gap.

2. The planar illumination device of claim 1, wherein the at least one mirror is spaced apart from the bottom surfaces of the light guide elements.

3. The planar illumination device of claim 1, wherein the at least one mirror comprises first and second mirrors.

4. The planar illumination device of claim 3, wherein at least a portion of the second mirror overlaps with a portion of the first mirror under the gap.

9. The planar illumination device of claim 1, wherein each of the first and second light-guide elements has a side wall facing the gap, the side walls being externally reflective to reflect light into the gap.

10. The planar illumination device of claim 9, wherein each reflective side wall is a partly reflecting mirror whose reflectivity varies along a length thereof.

11. The planar illumination device of claim 1, wherein the at least one mirror is angled relative to the bottom surfaces.

13. The planar illumination device of claim 1, wherein the at least one mirror is a specular mirror.

14. The planar illumination device of claim 1, wherein the at least one mirror is a diffusive mirror.

15. The planar illumination device of claim 1, wherein the bottom surfaces of the light-guide elements comprise out-coupling features.

5. A planar illumination device comprising:

first and second light-guide elements each comprising an illumination surface and an opposed bottom surface, the first and second light-guide elements being separated by a gap;

at least one mirror in opposition to the bottom surfaces of the light-guide elements and underlying the gap; and

a position changer for changing a position of the at least one mirror relative to the bottom surfaces of the light guide elements.

6. The planar illuminating area of claim 5, wherein the position changer is responsive to temperature.

7. The planar illumination device of claim 5, wherein the position changer includes an expandable element positioned below the mirror.

8. The planar illumination device of claim 5, wherein the position changer comprises at least one expandable element and at least one fulcrum positioned above the mirror.

12. The planar illumination device of claim 6, wherein the angle is along a light-guiding direction.

18. A planar illumination device comprising:

first and second light-guide elements separated by a gap, each light-guide element comprising;

an illumination surface;

an opposed bottom surface; and

an externally reflective side wall facing the gap.

16. The planar illumination device of claim 19, wherein the out-coupling features comprise bumps.

19. The planar illumination device of claim 18, wherein each reflective side wall is a partly reflecting mirror whose reflectivity varies along a length thereof.

20. A method of illumination comprising the steps of:

providing first and second light-guide elements each comprising an illumination surface and an opposed bottom surface, the first and second light-guide elements being separated by a gap;

providing at least one mirror in opposition to the bottom surfaces of the light-guide elements and underlying the gap; and

changing a position of the at least one mirror relative to the bottom surfaces of the light guide elements in response to changes in a width of the gap.

17. The planar illumination device of claim 20, wherein the out-coupling features comprise grooves.