Subwavelength optical microstructure light collimating films

• US 6,356,389 B1
• Filed: 11/12/1999
• Issued: 03/12/2002
• Est. Priority Date: 11/12/1999
• Status: Expired due to Fees

• Current Assignee: Reflexite
• Original Assignee: Reflexite
• Inventors: Lu, Xiao-Jing, Mullen, Patrick W., Nilsen, Robert B.
• Primary Examiner(s): Ben, Loha
• Application Number:
  US09/438,912
• Time in Patent Office: 851 Days
• Field of Search: 359/619, 359/625, 359/566, 359/569, 359/571, 359/599, 359/251, 362/30, 362/31, 362/26, 362/97, 362/330, 362/331, 385/133, 385/146, 385/901
• US Class Current: 359/625
• 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 prisms, and the second side includes a plurality of subwavelength optical microstructures. Another embodiment includes a back lighting display device having a lighting means, a display panel, and a sheeting having a first side and a second side, wherein the first side includes a series of prisms, and the second side includes a plurality of subwavelength optical microstructures. A preferred embodiment includes a back lighting display device having a first collimating film having a first surface with a subwavelength optical microstructure thereon and a second surface with linear prisms having an included angle of greater than about 95 degrees, and a second collimating film having a first surface with a subwavelength optical microstructure thereon and a second surface with linear prisms having an included angle of less than about 85 degrees.

Claims

1. A light directing film comprising:

a sheeting having a first side and a second side, wherein said first side includes a series of prisms, and said second side includes a plurality of moth-eye structures.

2. The light directing film of claim 1 wherein said prisms include linear prisms.

3. The light directing film of claim 2 wherein said linear prisms run the width of the sheeting.

4. The light directing film of claim 3 wherein said linear prisms include triangular prisms arranged side-by-side.

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

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

7. The light directing film of claim 4 wherein said triangular prisms include a top angle in a range of between about 60 and 85 degrees.

8. The light directing film of claim 4 wherein said triangular prisms include a top angle in a range of between about 95 and 120 degrees.

9. The light directing film of claim 2 wherein said linear prisms are pitched at regular intervals.

10. The light directing film of claim 2 wherein said linear prisms are pitched in the range of between about 0.0005 and 0.25 inches.

11. The light directing film of claim 1 wherein said second side includes moth-eye structures spaced about 0.2 micron apart.

12. The light directing film of claim 1 wherein said moth-eye structures have depth to width ratio in a range of between about one and three.

13. A back lighting display device, comprising:

a) a lighting device;

b) a display panel disposed adjacent to the lighting device; and

c) a sheeting disposed adjacent to the display panel, the sheeting having a first side and a second side, wherein said first side includes a series of prisms, and said second side includes a plurality of moth-eye structures.

14. A light collimating structure, comprising:

a) a first collimating film having a first surface with a moth-eye structure thereon and a second surface with linear prisms having an included angle of equal or greater than about 95 degrees, and

b) a second collimating film having a first surface with a moth-eye structure thereon and a second surface with linear prisms having an included angle of equal or less than about 85 degrees.

15. The light collimating structure of claim 14 wherein the moth-eye structure of the first collimating film and the moth-eye structure of the second collimating film face each other.