Edge-lit optical system having optical elements on two surfaces

• US 7,810,982 B2
• Filed: 02/03/2009
• Issued: 10/12/2010
• Est. Priority Date: 02/23/1999
• Status: Expired due to Fees

• Current Assignee: Rambus Delaware LLC (Rambus Inc.)
• Original Assignee: Rambus International Ltd (Rambus Inc.)
• Inventors: McCollum, Timothy A., Parker, Jeffery R., Ezell, Robert M.
• Primary Examiner(s): Negron; Ismael
• Application Number:
  US12/364,637
• Publication Number:
  US 20090141517A1
• Time in Patent Office: 616 Days
• Field of Search: 362/620, 362/626, 362/622, 362/612, 362/624, 362/561, 349/65
• US Class Current: 362/620
• CPC Class Codes: A61B 2090/309 using white LEDs
• CPC Class Codes: A61M 2021/0044 by the sight sense
• CPC Class Codes: A61M 21/02 for inducing sleep or relaxation, e.g. by direct nerve stimulation, hypnosis, analgesia for massage A61H; electrotherapy A61N, e.g. applying alternating or intermittent electric currents for producing anaesthesia A61N1/36021
• CPC Class Codes: A61N 2005/063 comprising light transmitting means, e.g. optical fibres
• CPC Class Codes: A61N 2005/0652 Arrays of diodes
• CPC Class Codes: A61N 5/0621 Hyperbilirubinemia, jaundice treatment
• CPC Class Codes: F21V 11/00 Screens not covered by groups F21V1/00, F21V3/00, F21V7/00 or F21V9/00 characterised by cooling arrangements F21V29/502
• CPC Class Codes: F21V 5/10 comprising photoluminescent material
• CPC Class Codes: G02B 6/0018 Redirecting means on the surface of the light guide
• CPC Class Codes: G02B 6/002 by shaping at least a portion of the light guide, e.g. with collimating, focussing or diverging surfaces
• 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 6/0028 Light guide, e.g. taper
• CPC Class Codes: G02B 6/0031 Reflecting element, sheet or layer
• 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 6/0043 provided on the surface of the light guide
• CPC Class Codes: G02B 6/0053 Prismatic sheet or layer; Brightness enhancement element, sheet or layer
• CPC Class Codes: G02B 6/006 to produce indicia, symbols, texts or the like
• CPC Class Codes: G02B 6/0061 to provide homogeneous light output intensity
• CPC Class Codes: G02B 6/0065 Manufacturing aspects; Material aspects
• CPC Class Codes: G02B 6/0068 : Arrangements of plural sources, e.g. multi-colour light sources
• CPC Class Codes: H01H 2219/062 : Light conductor
• CPC Class Codes: H01H 2221/07 : transparent

Abstract

Optical assembly includes a light source adjacent a light input edge and generally parallel and planar first and second surfaces each comprising respective patterns of well defined optical elements that are quite small in relation to the length and width of the optical assembly. At least some of the optical elements of each pattern include a respective sloped surface for directing at least some light emitted from the light source. The respective slope angle of the sloped surface of at least some of the optical elements of one of the patterns is different from the respective slope angle of the sloped surface of at least some of the optical elements of the other pattern such that more of the light is emitted from one of the surfaces than is emitted from the other surface.

Claims

1. An optical assembly, comprising:

a light input edge;

a light source positioned adjacent the light input edge, the light source being quite small in relation to a length and width of the optical assembly;

a generally planar first surface comprising a first pattern of well defined optical elements that are projections or depressions on or in the first surface, at least some of the optical elements of the first pattern being quite small in relation to a length and width of the optical assembly;

a generally planar second surface generally parallel to the first surface, the second surface comprising a second pattern of well defined optical elements that are projections or depressions on or in the second surface;

wherein;

at least some of the optical elements of the first pattern include a first sloped surface for directing at least some light emitted from the light source, the optical elements of the first pattern varying over the first surface;

at least some of the optical elements of the second pattern include a second sloped surface for directing at least some light emitted from the light source;

the respective first sloped surface of at least some of the optical elements of the first pattern have a respective first slope angle that is different from a respective second slope angle of the respective second sloped surface of at least some of the optical elements of the second pattern such that more of the light emitted from the light source is emitted from one of the first and second surfaces than is emitted from the other one of the first and second surfaces; and

the optical assembly additionally comprises a reflector layer positioned adjacent the other one of the first and second surfaces.

2. The optical assembly of claim 1, wherein the respective first slope angle of the at least some of the optical elements of the first pattern is different from the respective second slope angle of the at least some of the optical elements of the second pattern such that the more of the light emitted from the light source is emitted from the first surface than is emitted from the second surface.

3. The optical assembly of claim 1, wherein the respective first slope angle of the at least some of the optical elements of the first pattern is different from the respective second slope angle of the at least some of the optical elements of the second pattern such that the more of the light emitted from the light source is emitted from the second surface than is emitted from the first surface.

4. The optical assembly of claim 1, wherein:

the first surface and the second surface define a first major plane and a second major plane, respectively;

the respective first slope angle of the at least some of the optical elements of the first pattern is between the first sloped surface and the first major plane, as measured along a plane perpendicular to the first major plane and that includes a virtual line connecting a center point of the light source to a center point of the optical element;

the respective second slope angle of the at least some of the optical elements of the second pattern is between the second sloped surface and the second major plane, as measured along a plane perpendicular to the second major plane and that includes a virtual line connecting the center point of the light source to a center point of the optical element; and

the optical elements of the first pattern have an average slope angle that is less than an average slope angle of the optical elements of the second pattern.

5. The optical assembly of claim 1, wherein the optical elements of the second pattern that are remote from the light input edge are configured to reduce the spread of at least some of the light emitted from the light source along a direction parallel to the light input edge and to the second surface.

6. The optical assembly of claim 1, wherein the light source comprises a light emitting diode.

7. The optical assembly of claim 1, wherein at least some of the optical elements of the first pattern intersect other optical elements of the first pattern.

8. The optical assembly of claim 1, wherein at least some of the optical elements of the second pattern intersect other optical elements of the second pattern.

9. The optical assembly of claim 1, wherein the optical elements of the first pattern have an area density that increases with increased distance from the light source.

10. The optical assembly of claim 1, wherein the optical elements of the second pattern have an area density that increases with increased distance from the light source.

11. The optical assembly of claim 1, comprising a light guide substrate and an optical sheet or film, wherein the light guide substrate includes the light input edge and the second surface, and the optical sheet or film includes the first surface.

12. The optical assembly of claim 1, wherein at least some of the optical elements of the first pattern comprise an additional sloped surface that intersects the respective first sloped surface to form a non-linear ridge that is curved towards the light source.

13. The optical assembly of claim 1, wherein at least some of the optical elements of the first pattern that are remote from the light source comprise an additional sloped surface that intersects the respective first sloped surface to form a non-linear ridge that is curved towards a direction perpendicular to the light input edge.

14. The optical assembly of claim 1, wherein the optical elements of the first pattern have a length and a width, the length being greater than the width, and the optical elements of the first pattern that are remote from the light source have a length direction that is approximately parallel to the light input edge.

15. The optical assembly of claim 1, wherein the optical elements of the first pattern that are remote from the light source are arranged in substantially the same direction.

16. The optical assembly of claim 1, wherein the light input edge is located at or near a corner of the assembly.

17. The optical assembly of claim 1, wherein the light source is configured to emit light having a greater width component than height component.

18. The optical assembly of claim 1, wherein the respective first slope angle of the at least some of the optical elements of the first pattern is different from the respective second slope angle of the at least some of the optical elements of the second pattern such that at least 60% of the light emitted from the optical assembly is emitted from the one of the surfaces.

19. The optical assembly of claim 1, comprising a light guide substrate that includes the light input edge.

20. The optical assembly of claim 19, wherein the light guide substrate includes a transition region that is in close proximity to the light input edge and configured to spread the light from the light source.

21. The optical assembly of claim 19, wherein the light guide substrate includes the second surface.

22. The optical assembly of claim 19, wherein the light guide substrate includes the first surface.

23. The optical assembly of claim 19, wherein the light guide substrate includes the reflector layer.

24. The optical assembly of claim 19, wherein the light guide substrate is a multi-layer structure including the first surface and the second surface.