Light redirecting films having a pattern of dome-shaped optical elements

• US 8,668,371 B2
• Filed: 10/26/2012
• Issued: 03/11/2014
• Est. Priority Date: 02/23/1999
• Status: Expired due to Fees

• Current Assignee: Rambus Delaware
• Original Assignee: Rambus Delaware LLC (Rambus Inc.)
• Inventors: Parker, Jeffery R., McCollum, Timothy A., Ezell, Robert M.
• Primary Examiner(s): Negron, Ismael
• Application Number:
  US13/661,429
• Publication Number:
  US 20130107543A1
• Time in Patent Office: 501 Days
• Field of Search: 362/618, 362/620, 362/622, 362/624, 362/626, 362/627, 362/330, 362/337, 362/339, 359/599, 359/615, 359/837, 385/130
• US Class Current: 362/618
• CPC Class Codes: F21V 5/002 using microoptical elements for redirecting or diffusing light
• CPC Class Codes: G02B 27/00 Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
• CPC Class Codes: G02B 3/0043 Inhomogeneous or irregular arrays, e.g. varying shape, size, height
• CPC Class Codes: G02B 3/08 with discontinuous faces, e.g. Fresnel lens diffractive Fresnel lenses G02B5/1876
• CPC Class Codes: G02B 5/045 Prism arrays
• 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 6/0053 Prismatic sheet or layer; Brightness enhancement element, sheet or layer
• CPC Class Codes: G02B 6/0061 to provide homogeneous light output intensity
• CPC Class Codes: G02B 6/0065 Manufacturing aspects; Material aspects

Abstract

Light redirecting film comprises a thin optically transparent substrate having a pattern of individual optical elements formed as projections on a light exit surface of the film. At least some of the projections comprise a dome-shaped surface on the light exit surface.

Claims

1. A light redirecting film comprising:

a thin optically transparent substrate having a light entrance surface and a light exit surface opposite the light entrance surface; and

a pattern of individual optical elements formed as projections on the light exit surface, the individual optical elements having a width and length substantially smaller than a width and length of the substrate, at least some of the projections comprising a dome-shaped top surface on the light exit surface, the light entrance surface being in close proximity to a light guide for receiving light from the light guide and redirecting the light passing through the light redirecting film out through the light exit surface, wherein the individual optical elements are randomized on the light exit surface, and wherein the individual optical elements randomly intersect each other over an intersection volume of the intersecting optical elements.

2. The light redirecting film of claim 1, wherein the individual optical elements randomly differ in density, size, height, position, slope or orientation on the light exit surface.

3. The light redirecting film of claim 1, wherein the individual optical elements substantially cover a portion of the light exit surface.

4. A light redirecting film comprising:

a thin optically transparent substrate having a light entrance surface and a light exit surface opposite the light entrance surface; and

a pattern of individual optical elements formed as projections on a major surface of the substrate, the individual optical elements having a width and length many times smaller than a width and length of the substrate, at least some of the projections comprising a transversely rounded or curved top surface, the light entrance surface being in close proximity to a light guide for receiving light from the light guide and redirecting the light passing through the light redirecting film out through the light exit surface, wherein the individual optical elements are randomized on the major surface, and wherein the individual optical elements randomly intersect each other on the major surface over an intersection volume of the intersecting optical elements.

5. The light redirecting film of claim 4, wherein the individual optical elements randomly differ in density, size, height, position, slope or orientation on the major surface.

6. The light redirecting film of claim 4, wherein the individual optical elements substantially cover a portion of the major surface.

7. The light redirecting film of claim 4, wherein the major surface comprises the light exit surface.

8. The light redirecting film of claim 4, wherein the major surface comprises the light entrance surface.

9. The light redirecting film of claim 4, wherein at least some of the projections additionally comprise a side surface curved along a length thereof.

10. The light redirecting film of claim 9, wherein the side surface of at least some of the projections intersects the major surface of the substrate.

11. The light redirecting film of claim 10, wherein the intersection of the side surface of at least some of the projections with the major surface of the substrate forms at least a portion of a curved or circular perimeter.

12. The light redirecting film of claim 10, wherein the major surface comprises the light exit surface.