Brightness enhancement film using a linear arrangement of light concentrators

• US 7,160,017 B2
• Filed: 06/03/2004
• Issued: 01/09/2007
• Est. Priority Date: 06/03/2004
• Status: Expired due to Fees

• Current Assignee: SKC Hi-Tech & Marketing Co., Ltd.
• Original Assignee: Eastman Kodak Company
• Inventors: Kessler, David, Lee, Junwon
• Primary Examiner(s): Sember; Thomas M.
• Assistant Examiner(s): Rehm; Adam C.
• Application Number:
  US10/860,545
• Publication Number:
  US 20050270798A1
• Time in Patent Office: 950 Days
• Field of Search: 362/31, 362/606, 362/607, 362/617, 362/619, 362/620
• US Class Current: 362/620
• 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 6/0065 Manufacturing aspects; Material aspects

Abstract

A brightness enhancement article (30) provides light from a two-dimensional surface. The brightness enhancement article (30) has a plurality of light collecting structures (32), wherein each light collecting structure (32) is longitudinally extended in a length direction along the surface. Each light collecting structure (32) has an input aperture (33) optically coupled to a light-providing surface and an output aperture (35) distal from the input aperture (33), wherein the output aperture (35) has a surface area that is larger than the surface area of the input aperture (33). A pair of curved side walls (38) extend from the output aperture (35) toward the input aperture (33). In a cross section taken orthogonally with respect to the length direction, the curved side walls (38) approximate a parabolic curvature.

Claims

1. An illumination system comprising:

(a) a light providing element having an output surface;

(b) a brightness enhancement article comprising a plurality of light collecting structures, wherein each light collecting structure is longitudinally extended in a length direction along the output surface of the light providing element, each light collecting structure comprising;

(i) an input aperture optically coupled to the output surface of the light-providing element;

(ii) an output aperture distal from the input aperture, wherein the output aperture has a surface area that is larger than the surface area of the input aperture; and

,

(iii) a pair of curved side walls extending from the output aperture toward the input aperture;

wherein, in a cross section taken orthogonally with respect to the length direction, the curved side walls approximate a parabolic curvature;

(c) a reflective surface, along at least a portion of the surface of the light providing element opposite the output surface, for reflecting light back into the light providing element; and

,

(d) a prism surface optically coupled with the surface of the light providing element and opposite the output surface, the prism surface comprising prism structures longitudinally extended in a width direction, the width direction being substantially orthogonal to the length direction of the brightness enhancement article.

2. An illumination system according to claim 1, further comprising a light conditioning article for conditioning light provided from the brightness enhancement article.

3. An illumination system according to claim 2 wherein the light conditioning article comprises a reflective polarizer.

4. An illumination system according to claim 2 wherein the light conditioning article comprises a diffuser.

5. An illumination system according to claim 1 wherein adjacent light collecting structures are disposed substantially in parallel with respect to each other.

6. An illumination system according to claim 1 wherein the output surface and at least one light collecting structure are the same material.

7. An illumination system according to claim 1 wherein the width of the output aperture varies by more than 10% over the length of at least one light collecting structure.

8. An illumination system according to claim 1 wherein the pitch between adjacent light collecting structures is substantially equal.

9. An illumination system according to claim 1 wherein the pitch between any two adjacent light collecting structures is varied by more than 10% over the length of the brightness enhancement article.

10. An illumination system according to claim 1 wherein light collecting structures are arranged substantially radially with respect to a light source.

11. An illumination system according to claim 1 wherein adjacent lengths of the light collecting structure are arranged to follow a curved path.

12. An illumination system according to claim 1 wherein adjacent lengths of the light collecting structure are arranged to follow a path of varying curvature.