Light panel with improved diffraction

• US 6,773,126 B1
• Filed: 11/27/2001
• Issued: 08/10/2004
• Est. Priority Date: 05/28/1999
• Status: Expired due to Term

• Current Assignee: Modilis Holdings LLC
• Original Assignee: Oy Modilis Ltd.
• Inventors: Rinko, Kari, Hatjasalo, Leo
• Primary Examiner(s): Sember, Thomas M.
• Assistant Examiner(s): Sawhney, Hargobind S.
• Application Number:
  US09/979,944
• Time in Patent Office: 987 Days
• Field of Search: 362/31, 362/30, 362/555, 362/231, 362/330, 362/336, 362/337, 362/26, 362/27
• US Class Current: 362/601
• CPC Class Codes: G02B 6/0036 2-D arrangement of prisms, protrusions, indentations or roughened surfaces
• CPC Class Codes: G02B 6/0038 Linear indentations or grooves, e.g. arc-shaped grooves or meandering grooves, extending over the full length or width of the light guide
• CPC Class Codes: G02B 6/0041 provided in the bulk of the light guide
• CPC Class Codes: G02B 6/0068 Arrangements of plural sources, e.g. multi-colour light sources
• CPC Class Codes: G09F 13/04 Signs, boards or panels, illuminated from behind the insignia
• CPC Class Codes: G09F 13/0409 Arrangements for homogeneous illumination of the display surface, e.g. using a layer having a non-uniform transparency arrangements of reflectors G09F13/14

Abstract

A light panel that includes a light source and a panel element operatively connected to the light source. The panel element includes a substantially transparent light transmitting material and is operative as a waveguide panel inside which light beams received from the light source propagate with total reflection. A diffractive outcoupling system is arranged on the panel element over a light surface of the panel element and is operative to outcouple the light beams from inside the panel element. The diffractive outcoupling system includes a plurality of local grating elements. The local grating elements have a plurality configurations and are optimized such that a diffraction efficiency is a function of location.

Claims

1. A light panel, comprising:

at least one light source;

a panel element operatively connected to the at least one light source, the panel element comprising a substantially transparent light transmitting material; and

a diffractive outcoupling system arranged over at least a portion of a light surface of the panel element, the diffractive outcoupling system comprising a plurality of local grating elements, each of the plurality of local grating elements having a diffraction efficiency and comprising at least one pattern of at least one of grooves and recesses, the diffraction efficiency of the local grating elements varies over the outcoupling system as a function of location by varying at least one of filling factor, shape, profile, size, and orientation of the at least one of grooves and recesses over the diffractive outcoupling system.

2. The light panel according to claim 1, further comprising:

a diffractive incoupling system operative to introduce light beams from the light source into the panel element.

3. The light panel according to claim 2, wherein the diffractive incoupling system comprises at least one of a binary beam distributor, a local grating structure, and a diffuser.

4. The light panel according to claim 2, wherein the diffractive incoupling system is arranged at a boundary surface of the panel element.

5. The light panel according to claim 2, wherein the diffractive incoupling system incouples light by means of geometrical contours of the boundary surface.

6. The light panel according to claim 2, wherein the incoupling system is arranged at a perimeter of the panel element.

7. The light panel according to claim 1, wherein the local grating elements comprise at least one of multi-shaped pixels, binary pixels, multi-shaped units and binary units.

8. The light panel according to claim 1, wherein the light source comprises at least one longitudinally successive LED operative to activate the panel element by transmitting light beams therein.

9. The light panel according to claim 1, wherein the panel element comprises a thin and optically clear material having a thickness of 0.1-4 mm.

10. The light panel according to claim 1, wherein the panel element comprises a polymeric, elastomeric, or ceramic sheet or film.

11. The light panel according to claim 1, wherein the panel element comprises at least one of a flexible and a preformed material.

12. The light panel according to claim 1, wherein the light surface of the panel element is adapted to activate by maintaining the entire panel element at a local radius of curvature that is sufficiently small, such that a threshold angle of total reflection is not exceeded as a light beam travels within the panel element.

13. The light panel according to claim 1, wherein the diffractive outcoupling system is configured such that the panel element comprises a different color in one or more sections thereof.

14. The light panel according to claim 13, wherein the different color is provided by one or more independently controlled lighting units producing light of various colors.

15. The light panel according to claim 13, wherein the different color is provided by varying at least one of an intensity and a supply voltage of the light source.

16. The light panel according to claim 1, wherein the panel element comprises a responsive surface operative to carry out at least one of eliminating light beams transmitted from the outcoupling system and preventing formation of pronounced light spots.

17. The light panel according to claim 16, wherein the responsive surface comprises at least one of a reflector and a diffuser.

18. The light panel according to claim 1, wherein the panel element is configured as a closed box-type structure, wherein the incoupling system comprises a beam distributor arranged at a front surface or a back surface of the panel element, and wherein the beam distributor is operative to focus light beams delivered from the light source to propagate with total reflection within the panel element.

19. The light panel according to claim 1, wherein the at least one panel element is operative as a waveguide panel inside which light beams received from the light source propagate with total reflection.

20. The light panel according to claim 1, wherein the a diffractive outcoupling system is operative to outcouple the light beams from inside the panel element.

21. The light panel according to claim 1, wherein the diffraction efficiency of each local grating element varies over the outcoupling system by varying at least one of filling factor, shape, profile, size, and orientation of the at least one of grooves and recesses within each local grating element.

22. The light panel according to claim 1, wherein discontinuities exist in the at least one of grooves and recesses among at least a portion of the local grating elements.

23. The light panel according to claim 1, wherein the outcoupling system uniformly outcouples light over its surface.

24. The light panel according to claim 1, wherein at least a portion of the local grating elements vary in at least one of size and shape.