Subwavelength optical microstructure light collimating films

• US 6,570,710 B1
• Filed: 10/06/2000
• Issued: 05/27/2003
• Est. Priority Date: 11/12/1999
• Status: Expired due to Fees

• Current Assignee: Reflexite
• Original Assignee: Reflexite
• Inventors: Nilsen, Robert B., Lu, Xiao-Jing, Mullen, Patrick W.
• Primary Examiner(s): Ben, Loha
• Application Number:
  US09/684,455
• Time in Patent Office: 963 Days
• Field of Search: 359/619, 359/625, 359/251, 359/566, 359/569, 359/571, 359/576, 359/599, 362/26, 362/30, 362/31, 362/32, 362/97, 362/330, 362/331, 385/133, 385/146, 385/901
• US Class Current: 359/625
• CPC Class Codes: G02B 1/11 Anti-reflection coatings
• CPC Class Codes: G02B 1/118 having sub-optical wavelength surface structures designed to provide an enhanced transmittance, e.g. moth-eye structures
• CPC Class Codes: G02B 5/045 Prism arrays
• CPC Class Codes: G02B 5/124 plural reflecting elements forming part of a unitary plate or sheet
• CPC Class Codes: G02B 6/0036 2-D arrangement of prisms, protrusions, indentations or roughened surfaces
• CPC Class Codes: G02B 6/0053 Prismatic sheet or layer; Brightness enhancement element, sheet or layer
• CPC Class Codes: G03B 21/62 Translucent screens

Abstract

A light collimating film has a sheeting having a first side and a second side, wherein the first side includes a series of linear optical elements having a primary axis running the length of the optical elements, and the second side includes a plurality of subwavelength optical microstructures being oriented at about 90 degrees relative to the primary axis of the linear optical elements. Another embodiment includes a back lighting display device having a lighting device, a display panel, and a sheeting having a first side and a second side, wherein the first side includes a series of linear prisms having peaks, and the second side includes a plurality of subwavelength optical microstructures being oriented at about 90 degrees relative to the peaks of the linear prisms. Yet another embodiment includes a light collimating structure having a first collimating film having a first surface with a plurality of subwavelength optical microstructures thereon and a second surface with first linear prisms having peaks, the subwavelength optical microstructures being oriented at about 90 degrees relative to the peaks of the first linear prisms, and a second collimating film having a first surface with a plurality of subwavelength optical microstructures thereon and a second surface with second linear prisms having peaks, the subwavelength optical microstructures being oriented at about 90 degrees relative to the peaks of the second linear prisms.

Claims

1. A light collimating film comprising a sheeting having a first side and a second side, wherein said first side includes a series of linear optical elements having a primary axis running the length of the optical elements, and said second side includes a plurality of moth-eye structures, said moth-eye structures being oriented at about 90 degrees relative to the primary axis of said linear optical elements.

2. The light collimating film of claim 1 wherein said linear optical elements include linear prisms that run the width of the sheeting.

3. The light collimating film of claim 1 wherein said linear optical elements include linear prisms having triangular prisms arranged side-by-side.

4. The light collimating film of claim 3 wherein said triangular prisms include a top angle in a range of between about 60 and 120 degrees.

5. The light collimating film of claim 4 wherein said linear prisms include triangular prisms that are isosceles in shape.

6. The light collimating film of claim 3 wherein said triangular prisms include a top angle in a range of between about 60 and 85 degrees.

7. The light collimating film of claim 3 wherein said triangular prisms include a top angle in a range of between about 95 and 120 degrees.

8. The light collimating film of claim 3 wherein said triangular prisms include a top angle of about 88 degrees.

9. The light collimating film of claim 3 wherein said triangular prisms include a top angle of about 89 degrees.

10. The light collimating film of claim 1 wherein said linear optical elements are pitched at regular intervals.

11. The light collimating film of claim 1 wherein said linear optical elements include lenticular linear elements.

12. The light collimating film of claim 1 wherein said linear optical elements are pitched in the range of between about 0.0127 and 6.35 millimeters.

13. The light collimating film of claim 1 wherein said moth-eye structures include linear moth-eye structures.

14. The light collimating film of claim 13 wherein said second side includes linear moth-eye structures spaced about 0.15 micrometer apart.

15. The light collimating film of claim 13 wherein said linear moth-eye structures have depth to width ratio in range of between about one and to three.

16. The light collimating film of claim 13 wherein said linear moth-eye structures include a period in the range of between about 0.15 and 10.0 micrometers.

17. A back lighting display device, comprising:

a) a lighting device;

b) a display panel; and

c) a sheeting having a first side and a second side, wherein said first side includes a series of linear prisms having peaks, and said second side includes a plurality of linear moth-eye structures, said linear moth-eye structures being oriented at about 90 degrees relative to the peaks of said linear prisms.

18. The display device of claim 17 further comprising a second sheeting having a first side and a second side, wherein said first side includes a series of linear prisms having peaks, and said second side includes a plurality of linear moth-eye structures, said linear moth-eye structures being oriented at about 90 degrees relative to the peaks of said linear prisms.

19. The display device of claim 17 wherein said linear prisms include triangular prisms having a top angle of about 88 degrees.

20. The display device of claim 17 wherein said linear prisms include triangular prisms having a top angle of about 89 degrees.

21. A light collimating structure, comprising:

a) a first collimating film having a first surface with a plurality of linear moth-eye structures thereon and a second surface with first linear prisms having peaks, the linear moth-eye structures being oriented at about 90 degrees relative to the peaks of said first linear prisms; and

b) a second collimating film having a first surface with a plurality of linear moth-eye structures thereon and a second surface with second linear prisms having peaks, the linear moth-eye structures being oriented at about 90 degrees relative to the peaks of said second linear prisms.

22. The light collimating structure of claim 21 wherein the linear moth-eye structures of the first collimating film and the linear moth-eye structures of the second collimating film face each other.

23. A method of forming a light collimating film, comprising:

forming a series of linear prisms on a first side of a sheeting, the linear prisms including peaks; and

forming a plurality of linear moth-eye structures on a second side of the sheeting with the linear moth-eye structures being oriented at about 90 degrees relative to the peaks of the linear prisms.

24. The method of claim 23 further comprising the steps of:

forming a series of linear prisms on a first side of a second sheeting, the linear prisms also including peaks; and

forming a plurality of linear moth-eye structures on a second side of the second sheeting with the linear moth-eye structures being oriented at about 90 degrees relative to the peaks of the linear prisms.

25. The method of claim 24 further comprising the step of arranging the first and second sheetings such that the moth-eye structures of the first sheeting face the linear moth-eye structures of the second sheeting.