Light directing films

• US 9,004,726 B2
• Filed: 10/26/2012
• Issued: 04/14/2015
• Est. Priority Date: 10/27/2011
• Status: Active Grant

• Current Assignee: SVV Technology Innovations, Inc.
• Original Assignee: SVV Technology Innovations, Inc.
• Inventors: Vasylyev, Sergiy Victorovich
• Primary Examiner(s): Hollweg, Thomas A
• Application Number:
  US13/662,311
• Publication Number:
  US 20140119033A1
• Time in Patent Office: 900 Days
• Field of Search: 362/606, 362/362, 362/326, 362/330, 362/331, 362/334, 362/339
• US Class Current: 362/330
• CPC Class Codes: B29D 11/00355 with a refractive index gradient
• CPC Class Codes: B29D 11/0073 Optical laminates
• CPC Class Codes: F21V 5/02 of prismatic shape F21V5/04 takes precedence
• CPC Class Codes: G02B 5/0236 the diffusion taking place within the volume of the element
• CPC Class Codes: G02B 5/0278 used in transmission
• CPC Class Codes: G02B 6/001 the light being emitted along at least a portion of the lateral surface of the fibre
• CPC Class Codes: G02B 6/0053 Prismatic sheet or layer; Brightness enhancement element, sheet or layer

Abstract

Light directing films employing at least two layers forming a continuous corrugated boundary between major surfaces of the film. Light received by a major surface of the film is internally redirected by interacting with the facets of the corrugated inter-layer boundary and is emitted from the opposing major surface towards a new propagation direction which is different from the original propagation direction by up to 90 degrees. Light directing films may have additional layers and/or layer boundaries which may provide additional bend angles to light rays or otherwise diffuse the emitted beam.

Claims

1. A light directing film having generally smooth broad-area light input surface and an opposing broad-area light output surface, comprising:

a first optically transmissive layer having a first refractive index; and

a second optically transmissive layer having a second refractive index;

wherein said first and said second optically transmissive layers are disposed in contact with each other and form a continuous corrugated boundary, said boundary comprising a first plurality of boundary facets each forming a first dihedral angle with respect to a prevailing plane of said film alternating with a second plurality of boundary facets each forming a second dihedral angle with respect to a prevailing plane of said film, said second dihedral angle being different from said first dihedral angle, wherein each of said first and second dihedral angles is between 0° and

90°

, and wherein at least one of said first and second pluralities of boundary facets is configured to redirect light by means of at least refraction or a total internal reflection.

2. A light directing film as recited in claim 1, wherein said first optically transmissive layer has a lower refractive index than said second transmissive layer and wherein the outer boundary of said first optically transmissive layer forms said light input surface of said light directing film.

3. A light directing film as recited in claim 1, wherein said boundary comprises linear prismatic corrugations adjacent to one another and extending along a pre-defined reference line.

4. A light directing film as recited in claim 1, wherein said boundary comprises periodic prismatic corrugations.

5. A light directing film as recited in claim 1, wherein said boundary comprises prismatic corrugations having a triangular cross sectional shape.

6. A light directing film as recited in claim 1, further comprising additional light directing layers having at least one corrugated boundary.

7. A light directing film as recited in claim 1, wherein said light input surface is made attachable to a surface of an optical waveguide.

8. A light directing film as recited in claim 1, wherein said light input surface is made attachable to a surface of an optical waveguide and said waveguide is planar.

9. A light directing film as recited in claim 1, wherein said light input surface is made attachable to a surface of an optical waveguide and said waveguide is cylindrical.

10. A light directing film as recited in claim 1, further comprising additional means for bending light.

11. A light directing film as recited in claim 1, wherein said light output surface comprises a light diffusing surface texture.

12. A light directing film as recited in claim 1, wherein said light output surface comprises a plurality of prismatic microstructures or corrugations.

13. A multi-layer light directing film defined by opposing major surfaces extending parallel to each other, comprising:

one or more corrugated boundaries between alternating layers of different optical materials, said boundaries disposed between said major surfaces;

wherein each of said corrugated boundaries comprises a first plurality of facets each having a first dihedral angle with respect to either one of said major surfaces alternating with a second plurality of facets each having a second dihedral angle with respect to either one of said major surfaces, said first dihedral angle being different than said second dihedral angle; and

wherein each of said first and second dihedral angles is between 0° and

90°

.