CURVED SIDED CONE STRUCTURES FOR CONTROLLING GAIN AND VIEWING ANGLE IN AN OPTICAL FILM

• US 20100128351A1
• Filed: 11/21/2008
• Published: 05/27/2010
• Est. Priority Date: 11/21/2008
• Status: Abandoned Application

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Hoffend, Thomas R. JR., Keyes, Michael P., Hebrink, Timothy J., Ehnes, Dale L., Epstein, Kenneth A., Corrigan, Thomas R., Hoyle, Charles D., Bay, Randy S.
• Application Number:
  US12/275,631
• Publication Number:
  US 20100128351A1
• Time in Patent Office: Days
• US Class Current: 359/613
• CPC Class Codes: B29D 11/0074 Production of other optical elements not provided for in B29D11/00009- B29D11/0073
• CPC Class Codes: G02B 5/02 Diffusing elements; Afocal elements

Abstract

A method of making an optical film includes the steps of making a substrate having a first major surface and a second major surface opposite the first surface and forming a plurality of curved sided cone structures on the first surface. Each of the curved sided cone structures include a base located on the first surface, a vertex, and a curved side formed from an arc extending between the base and the vertex. The optical gain and viewing angle for the film can be controlled by adjusting angles representing a shape of each curved sided cone structure at its vertex and base.

Claims

1. A method of making an optical film, comprising the steps of:

making a substrate having a first major surface and a second major surface opposite the first surface; and

forming a plurality of curved sided cone structures on the first surface, each of the curved sided cone structures comprising a base located on the first surface, a vertex, and a curved side formed from an arc extending between the base and the vertex,

wherein the making and forming steps are performed using a microreplication process.

2. The method of claim 1, wherein the forming step includes forming the base of each of the curved sided cone structures in contact with the base of another one of the curved sided cone structures.

3. The method of claim 1, wherein the forming step includes forming the base of each of the curved sided cone structures separated by a space from the base of another one of the curved sided cone structures.

4. The method of claim 1, wherein the forming step includes forming the curved side of the curved sided cone structures as convex.

5. The method of claim 1, wherein the forming step includes forming the curved side of the curved sided cone structures as concave.

6. The method of claim 1, wherein the forming step includes forming the curved side of each of the curved sided cone structures as a plurality of discrete curved sides joined by ridges.

7. The method of claim 1, wherein the forming step includes forming the curved side of each of the curved sided cone structures as a plurality of curved segments joined by ridges.

8. The method of claim 1, wherein the forming step includes forming the curved side of each of the curved sided cone structures as a plurality of curved segments joined by flat portions.

9. The method of claim 1, wherein the forming step includes forming the curved side of each of the curved sided cone structures as symmetrical.

10. The method of claim 1, wherein the forming step includes forming the curved sided cone structures integral with the substrate.

11. An optical film, comprising:

a substrate having a first major surface and a second major surface opposite the first surface; and

a plurality of curved sided cone structures on the first surface, each of the curved sided cone structures comprising a base located on the first surface, a vertex, and a curved side formed from an arc extending between the base and the vertex,

wherein an optical gain and a viewing angle of the film are controlled by adjusting a first angle between a radius of the arc and a first axis perpendicular to the base and extending through the vertex and adjusting a second angle between the radius of the arc and a second axis perpendicular to the base and extending through the base.

12. The film of claim 11, wherein the first and second angles are adjusted to provide for a maximum optical gain of the film.

13. The film of claim 11, wherein the first and second angles are adjusted to provide for a maximum viewing angle of the film.

14. The film of claim 11, wherein the curved sided cone structures are arranged in a hexagonal lattice pattern on the substrate.