Optical film having a surface with rounded structures

• US 7,416,309 B2
• Filed: 12/30/2004
• Issued: 08/26/2008
• Est. Priority Date: 12/30/2004
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Ko, Byung-Soo, Whitney, Leland R., Chae, Dongwon
• Primary Examiner(s): CARIASO, ALAN B
• Application Number:
  US11/026,940
• Publication Number:
  US 20060146562A1
• Time in Patent Office: 1,335 Days
• Field of Search: 362/19, 362/561, 362/583, 362/606, 362/607, 362/618, 362/627, 362/330
• US Class Current: 362/19
• CPC Class Codes: G02B 6/0053 Prismatic sheet or layer; Brightness enhancement element, sheet or layer
• CPC Class Codes: G02B 6/0056 for producing polarisation effects, e.g. by a surface with polarizing properties or by an additional polarizing elements

Abstract

The present disclosure is directed to optical devices including a light source and an optical film having a first surface disposed to receive light from the light source and a second surface facing away from the light source. The second surface includes a two-dimensional array of closely packed substantially hemispherically-shaped structures. In some implementations of the present disclosure, the optical film further includes a substrate portion having an optical characteristic different from optical characteristics of the second surface comprising the two dimensional array.

Claims

1. An optical device comprising:

a light source;

an optical film having a first surface disposed to receive light from the light source, the optical film comprising a polarizer and a substrate portion, the optical film further having a second surface facing away from the light source, the second surface comprising a two-dimensional array of closely packed substantially hemispherically-shaped structures having a refractive index that is lower than a refractive index of the substrate portion; and

a liquid crystal display panel disposed to receive light transmitted through the optical film;

wherein light transmitted through the optical film exhibits uniform polarization and wherein the two-dimensional array of closely packed substantially hemispherically-shaped structures redirects light transmitted through the optical device so that the film exhibits axial output luminance gain of at least about 1.1 relative to the axial output luminance of the optical device absent the optical film.

2. The optical device of claim 1, wherein the optical film comprises a linear reflective polarizer.

3. The optical device of claim 1, wherein the second surface comprises a plurality of closely packed substantially hemispherically-shaped depressions.

4. The optical device of claim 1, wherein the second surface comprises a plurality of closely packed substantially hemispherically-shaped protrusions.

5. The optical device of claim 1, wherein the second surface comprises a pluralities of closely packed substantially hemispherically-shaped structures having a radius of at least about 5 μ

m.

6. The optical device of claim 1, wherein, the second surface comprises a plurality of closely packed substantially hemispherically-shaped structures having a radius of about 10 about 50 μ

m.

7. The optical device of claim 1, wherein the second surface comprises pluralities of closely packed substantially hemispherically-shaped structures of at least two different radii.

8. The optical device of claim 1, further comprising a light distribution element optically coupled to the light source and disposed to supply light to the optical film.

9. The optical device of claim 8, wherein the light distribution element is a lightguide.

10. An optical device comprising:

a light source;

an optical film having a first surface disposed to receive light from the light source and a second surface facing away from the light source, the second surface comprising a two dimensional array including a first plurality of substantially hemispherically-shaped structures having a first radius and a second plurality of substantially hemispherically-shaped structures having a second radius different from the first radius, wherein the first and second pluralities of structures are closely packed; and

a liquid crystal display panel disposed to receive light transmitted through the optical film;

wherein the optical film comprises a substrate portion having an optical characteristic different from optical characteristics of the second surface comprising the two dimensional array; and

wherein the two-dimensional array of pluralities of substantially hemispherically-shaped structures redirects light transmitted through the optical device exhibits so that the film exhibits axial output luminance gain of at least about 1.1 relative to the axial output luminance of the optical device absent the optical film.

11. The optical device of claim 10, wherein the substrate portion comprises at least one of:

a polarizer film, a diffuser film, a brightness enhancing film, a turning film or a combination thereof.

12. The optical device of claim 10, wherein the optical film further comprises a substrate portion and wherein the closely packed substantially hemispherically-shaped structures have a refractive index that is lower than a refractive, index of the substrate portion.

13. The optical device of claim 10, wherein the closely packed substantially hemispherically-shaped structures have an average radius of at least about 5 μ

m.

14. The optical device of claim 10, further comprising a light distribution element optically coupled to the light source and disposed to supply light to the optical film.

15. The optical device of claim 14, wherein the light distribution element is a lightguide.