Light redirecting film systems having pattern of variable optical elements

US 7,914,196 B2
Filed: 03/25/2008
Issued: 03/29/2011
Est. Priority Date: 06/27/1995
Status: Expired due to Fees

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1. A light redirecting film system comprising a backlight including at least one input edge for receiving light from a light source, and at least one light output surface for emitting light, the backlight having deformities that cause most of the light entering the input edge to be emitted from the light output surface at relatively low angles, and a light redirecting film in close proximity to the light output surface for receiving light emitted from the light output surface, the light redirecting film having a pattern of individual optical elements of well-defined shape that vary at different locations on the film to redistribute the light emitted from the light output surface toward a direction normal to the film.

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Abstract

Light redirecting film systems comprise a backlight having deformities that cause a majority of the light entering the input edge of the backlight to be emitted from a light output surface of the backlight. In close proximity to the light output surface is a light redirecting film that has a pattern of individual optical elements of well-defined shape to redistribute the light emitted by the light output surface toward a direction normal to the film.

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25 Claims

1. A light redirecting film system comprising a backlight including at least one input edge for receiving light from a light source, and at least one light output surface for emitting light, the backlight having deformities that cause most of the light entering the input edge to be emitted from the light output surface at relatively low angles, and a light redirecting film in close proximity to the light output surface for receiving light emitted from the light output surface, the light redirecting film having a pattern of individual optical elements of well-defined shape that vary at different locations on the film to redistribute the light emitted from the light output surface toward a direction normal to the film.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
- - 2. The system of claim 1 wherein the deformities of the backlight cause most of the light to be emitted from the light output surface at angles substantially greater than ninety degrees away from the input edge.
  - 3. The system of claim 1 wherein the size or shape of the optical elements are tailored to redistribute more of the light emitted from the light output surface of the backlight within a desired viewing angle.
  - 4. The system of claim 1 wherein at least some of the optical elements are oriented at different angles.
  - 5. The system of claim 1 wherein at least some of the optical elements have different slope angles.
  - 6. The system of claim 1 wherein at least some of the optical elements are oriented at different angles across the film to redistribute the light along two different axes.
  - 7. The system of claim 1 wherein the size of at least some of the optical elements varies across the film.
  - 8. The system of claim 1 wherein the density of the optical elements varies across the film.
  - 9. The system of claim 1 wherein the optical elements comprise depressions in or projections on the film.
  - 10. The system of claim 1 further comprising a liquid crystal display in close proximity to the film, wherein the variations in the pattern of optical elements on the film cause a change in angle of a light ray output distribution from the light output surface to make the light ray output distribution more acceptable to travel through the liquid crystal display.
  - 11. The system of claim 1 wherein the optical elements on the film are randomized in size, shape, position, depth, orientation, angle or density.
  - 12. The system of claim 1 wherein at least some of the optical elements include a combination of planar and curved surfaces.
  - 13. The system of claim 12 wherein the ratio of the areas of the planar and curved surfaces is selected to produce a desired viewing angle.
  - 14. The system of claim 1 wherein at least some of the optical elements overlap each other.
  - 15. The system of claim 14 wherein at least some of the optical elements intersect each other.
  - 16. The system of claim 14 wherein at least some of the optical elements interlock each other.
  - 17. The system of claim 14 wherein at least some of the optical elements are staggered with respect to each other.
  - 18. The system of claim 1 wherein the deformities of the backlight partially collimate light along one axis, and the optical elements of the film partially collimate the light emitted by the backlight along another axis perpendicular to the one axis.
  - 19. The system of claim 18 wherein at least some of the optical elements are quite small in relation to the width and length of the film and differ in size or shape to redistribute more of the light emitted by the backlight.
  - 20. The system of claim 18 wherein at least some of the optical elements are oriented at different angles relative to each other to redistribute more of the light emitted by the backlight within a desired viewing angle.
  - 21. The system of claim 18 wherein at least some of the optical elements are randomly distributed across the film.

22. A light redirecting film system comprising a backlight including at least one input edge for receiving light from a light source, and at least one light output surface for emitting light, the backlight having individual optical deformities of well-defined shape for causing 60 to 70% or more of the light received through the input edge to be reflected or refracted out of the light output surface, and a light redirecting film in close proximity to the light output surface for receiving light emitted from the light output surface, the light redirecting film having a pattern of individual optical elements of well-defined shape to redistribute the light emitted by the backlight toward a direction normal to the film.
- View Dependent Claims (23, 24, 25)
- - 23. The system of claim 22 wherein at least some of the deformities have rounded side walls for scattering the light in different directions within the backlight before the light is reflected or refracted out of the one output surface of the backlight.
  - 24. The system of claim 22 wherein a plurality of focused light sources are positioned in laterally spaced relation along the input edge.
  - 25. The system of claim 24 wherein the focused light sources are LEDs.

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Current Assignee
Delaware Display Group LLC (Acacia Research Corporation)
Original Assignee
Rambus International Ltd (Rambus Inc.)
Inventors
Parker, Jeffery R., McCollum, Timothy A., Ezell, Robert M.
Primary Examiner(s)
Negron, Ismael

Application Number

US12/054,680
Publication Number

US 20080239755A1
Time in Patent Office

1,099 Days
Field of Search

362/615, 362/618, 362/619, 362/620, 362/624, 362/625, 362/626, 362/606, 362/608, 362/627, 385/131, 349/65, 349/69, 349/70
US Class Current

362/618
CPC Class Codes

A61B 2090/309   using white LEDs

A61M 2021/0044   by the sight sense

A61M 21/02   for inducing sleep or relax...

A61N 2005/063   comprising light transmitti...

A61N 2005/0652   Arrays of diodes

A61N 5/0621   Hyperbilirubinemia, jaundic...

F21V 11/00   Screens not covered by grou...

F21V 5/10   comprising photoluminescent...

G02B 6/0018   Redirecting means on the su...

G02B 6/002   by shaping at least a porti...

G02B 6/0021   for housing at least a part...

G02B 6/0028   Light guide, e.g. taper

G02B 6/0031   Reflecting element, sheet o...

G02B 6/0036   2-D arrangement of prisms, ...

G02B 6/0038   Linear indentations or groo...

G02B 6/0043   provided on the surface of ...

G02B 6/0053   Prismatic sheet or layer; B...

G02B 6/006   to produce indicia, symbols...

G02B 6/0061   to provide homogeneous ligh...

G02B 6/0065   Manufacturing aspects; Mate...

G02B 6/0068 : Arrangements of plural sour...

H01H 2219/062 : Light conductor

H01H 2221/07 : transparent

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Light redirecting film systems having pattern of variable optical elements

First Claim

6 Assignments

Litigations

3 Petitions

Accused Products

Abstract

75 Citations

25 Claims

Specification

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Light redirecting film systems having pattern of variable optical elements

First Claim

6 Assignments

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Litigations

3 Petitions

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Accused Products

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Abstract

75 Citations

25 Claims

Specification

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Use Cases

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Others