Brightness enhancement film using an array of light concentrators

• US 20060250819A1
• Filed: 07/10/2006
• Published: 11/09/2006
• Est. Priority Date: 06/03/2004
• Status: Active Grant

• Current Assignee: SKC Haas Display Films Co., Ltd. (Dow, Inc.)
• Original Assignee: SKC Haas Display Films Co., Ltd. (Dow, Inc.)
• Inventors: Kessler, David, Lee, Junwon
• Granted Patent: US 7,581,867 B2
• Time in Patent Office: Days
• 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 and illumination system provides light from a two-dimensional surface. The brightness enhancement article has a plurality of light collecting structures wherein each light collecting structure is longitudinally extended in a length direction along the surface. The structures may have various lengthwise shapes such as being curved, concentric, radial, or of varying thickness.

Claims

1. A brightness enhancement article for providing light from a surface, the brightness enhancement article comprising a plurality of light collecting structures, wherein adjacent light collecting structures are arranged to follow curved paths on the light-providing surface, each light collecting structure comprising:

(a) an input aperture optically coupled to the light-providing surface;

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

, (c) a pair of curved side walls extending along the length direction and extended 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.

2. A brightness enhancement article according to claim 1 wherein adjacent light collecting structures are arranged to follow concentric circular paths on the light-providing surface.

3. A brightness enhancement article according to claim 1 wherein light collecting structures are arranged to follow curved paths with dimensional modifications along the length thereof.

4. A brightness enhancement article according to claim 1 wherein the light-providing surface and at least one light collecting structure have the same refractive index.

5. A brightness enhancement article according to claim 1 wherein the width of the output aperture varies over the length of the light collecting structure.

6. A brightness enhancement article according to claim 1 wherein the pitch between adjacent light collecting structures is substantially equal.

7. A brightness enhancement article according to claim 1 wherein the curved side walls provide total internal reflection to direct light incident at the input aperture to the output aperture.

8. A brightness enhancement article for providing light from a surface, the brightness enhancement article comprising a plurality of light collecting structures, wherein the light collecting structures are arranged radially with respect to each other, each light collecting structure comprising:

(a) an input aperture optically coupled to the light-providing surface;

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

,

(c) a pair of curved side walls extending along the length direction and extended 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.

9. An illumination system comprising:

(a) a light providing element having an output surface for light provided by a light source;

(b) a plurality of light collecting structures, wherein adjacent light collecting structures are arranged to follow curved paths on the light-providing surface, 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.

10. An illumination system according to claim 9 wherein the light source is a point light source.

11. An illumination system according to claim 9 wherein adjacent light collecting structures are arranged to follow concentric circular paths on the light-providing surface.

12. An illumination system according to claim 9 wherein light collecting structures are arranged to follow curved paths with dimensional modifications along the lengths thereof.

13. A brightness enhancement article according to claim 9 wherein the light-providing surface and at least one light collecting structure have the same refractive index.

14. A brightness enhancement article according to claim 9 wherein the width of the output aperture varies over the length of the light collecting structure.

15. A brightness enhancement article according to claim 9 wherein the pitch between adjacent light collecting structures is substantially equal.

16. A brightness enhancement article according to claim 9 wherein the curved side walls provide total internal reflection to direct light incident at the input aperture to the output aperture.

17. An illumination system comprising a plurality of light collecting structures, wherein the light collecting structures are arranged radially with respect to each other, each light collecting structure comprising:

(a) an input aperture optically coupled to the light-providing surface;

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

,

(c) a pair of curved side walls extending along the length direction and extended 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.

18. An illumination system of claim 17 wherein the light collecting structures are arranged radially and are centered on a point source light.