Light enhancing structures with a plurality of arrays of elongate features

• US 20070091617A1
• Filed: 11/08/2006
• Published: 04/26/2007
• Est. Priority Date: 01/13/2006
• Status: Active Grant

• Current Assignee: Avery Dennison Corporation
• Original Assignee: Avery Dennison Corporation, Optical Research Associates (Synopsys Incorporated)
• Inventors: Chapman, Steven, Cassarly, William, Couzin, Dennis
• Granted Patent: US 7,866,871 B2
• Time in Patent Office: Days
• US Class Current: 362/341
• CPC Class Codes: G02B 19/0028 refractive and reflective surfaces, e.g. non-imaging catadioptric systems
• CPC Class Codes: G02B 19/0052 the light source comprising a laser diode coupling into light guides using intermediate optical elements G02B6/4204; semiconductor lasers having optical devices external to the laser cavity H01S5/005
• CPC Class Codes: G02B 19/0061 the light source comprising a LED semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission H01L33/00
• CPC Class Codes: G02B 27/0994 Fibers, light pipes optical fibers per se G02B6/02
• CPC Class Codes: G02B 27/1006 for splitting or combining different wavelengths G02B27/1086, G02B27/141 take precedence
• CPC Class Codes: G02B 5/021 the diffusion taking place at the element's surface, e.g. by means of surface roughening or microprismatic structures
• CPC Class Codes: G02B 5/0278 used in transmission
• CPC Class Codes: G02B 5/045 Prism arrays
• CPC Class Codes: G02B 6/0025 Diffusing sheet or layer; Prismatic sheet or layer
• CPC Class Codes: G02B 6/0028 Light guide, e.g. taper
• CPC Class Codes: G02B 6/0046 Tapered light guide, e.g. wedge-shaped light guide
• CPC Class Codes: G02B 6/0053 Prismatic sheet or layer; Brightness enhancement element, sheet or layer

Abstract

Various embodiments comprise light recycling films comprising an array of parallel ridges and grooves that form prisms that selectively reflect or transmit light. In some embodiments, the light recycling film may be used in displays that include spatial light modulators comprising a plurality of pixels. The light recycling film can limit the field-of-view of the display and enhance the luminance within that field-of-view. Various embodiments comprising multiple arrays of ridges and/or grooves can enhance uniformity of illumination of the pixels in the spatial light modulator and reduce Moiré effects.

Claims

1. An optical member comprising an array of total internal reflection structures, said optical member comprising:

an optically transmissive film having a surface;

a first plurality of non-intersecting elongate features formed in said surface; and

a second plurality of non-intersecting elongate features formed in said surface, said first plurality of non-intersecting elongate features being oriented at an angle with respect to said second plurality of non-intersecting elongate features that is less than 30°

,

wherein each of said non-intersecting elongate features in said first plurality extends across said multiple non-intersecting elongate features in said second plurality thereby defining said total internal reflection structures.

2. The optical member of claim 1, wherein at least two of said non-intersecting elongate features comprise substantially parallel linear features.

3. The optical member of claim 1, wherein at least one of said non-intersecting elongate features varies in height or depth along its length.

4. The optical member of claim 1, wherein at least one of said non-intersecting elongate features comprises non-linear features.

5. The optical member of claim 4, wherein said non-linear feature undulates laterally.

6. The optical member of claim 1, wherein said non-intersecting elongate features comprise grooves.

7. The optical member of claim 1, wherein said non-intersecting elongate features comprise ridgelines.

8. The optical member of claim 1, wherein at least one of said total internal reflection structures comprises a prism having planar facets.

9. The optical member of claim 8, wherein said prism comprises a pyramid.

10. The optical member of claim 8, wherein said planar facets have rounded edges.

11. The optical member of claim 8, wherein each of said facets in said prisms has substantially the same projected area.

12. The optical member of claim 1, wherein said total internal reflection structures comprise inverted pyramids.

13. The optical member of claim 1, wherein said total internal reflection structures comprise everted pyramids.

14. The optical member of claim 1, wherein at least one of said total internal reflection structures comprises curved surfaces that totally internally reflect light.

15. The optical member of claim 1, wherein said film comprises a polymer.

16. The optical member of claim 1, wherein at least one of said first plurality and second plurality of non-intersecting elongate features has a vertex angle of about 89.25°

.

17. The optical member of claim 1, further comprising a diffuser on either side of said surface.

18. The optical member of claim 1, wherein at least one of said non-intersecting elongate features is linear.

19. An optical apparatus comprising the optical member of claim 1 and an illumination apparatus that backlights said optical member.

20. The optical member of claim 1, wherein each of said non-intersecting elongate features in said first plurality intersect each of said non-intersecting elongate features in said second plurality only once.

21. The optical member of claim 1, wherein said angle a is less than 10 degrees.

22. The optical member of claim 1, wherein said first plurality and second plurality of uniformly spaced prisms have pitches greater than 30.5 μ

m.

23. The optical member of claim 1, wherein said film has a thickness of 0.2 mm or less.