Structured optical film

Patent metadata

Field	Value
Publication number	US-9389355-B2
Application number	US-201314377204-A
Country	US
Kind code	B2
Filing date	Mar 7, 2013
Priority date	Mar 20, 2012
Publication date	Jul 12, 2016
Grant date	Jul 12, 2016

Abstract

An optical film includes a first structured major surface having a plurality of linear prisms extending along a same first direction and an opposing second structured major surface having a plurality of closely packed lenslets. The optical film exhibits a high optical uniformity and reduced sparkle.

First claim

What is claimed is:

1. An optical film, comprising:
a first structured major surface comprising a plurality of linear prisms extending along a same first direction; and
an opposing second structured major surface comprising a plurality of closely packed lenslets, each lenslet having a largest lateral dimension D, an equivalent circular diameter ECD and a finite focal length f corresponding to a focal spot, the plurality of closely packed lenslets having an average largest lateral dimension D avg , an average equivalent circular diameter ECD avg and an average focal length f avg , ECD avg /f avg being in a range from about 0.05 to about 0.20, D avg being less than about 50 micrometers, less than about 30% of the second structured major surface having a slope magnitude that is greater than about 5 degrees.

2. The optical film of claim 1 , wherein at least 90% of the second structured major surface is covered by the lenslets.

3. The optical film of claim 1 , wherein less than about 20% of the second structured major surface has a slope magnitude that is greater than about 5 degrees.

4. The optical film of claim 1 , wherein at least 80% of the lenslets in the plurality of lenslets have an equivalent circular diameter ECD that is less than about 27 micrometers.

5. The optical film of claim 1 , wherein at least 90% of the lenslets in the plurality of lenslets have a nearest neighbor focal spot distance that is less than about 25 micrometers.

6. The optical film of claim 1 , wherein the second structured major surface has an optical haze in a range from about 3% to about 25%.

7. The optical film of claim 1 , wherein an average effective transmission of the optical film is not less or is less than by no more than about 10% as compared to an optical film that has the same construction except that the second major surface is not structured.

8. The optical film of claim 1 , having an average effective transmission of at least 1.3.

9. An optical film, comprising:
a first structured major surface comprising a plurality of linear prisms extending along a same first direction; and
an opposing second structured major surface comprising a plurality of closely packed lenslets, each lenslet having an equivalent circular diameter ECD and a finite focal length f corresponding to a focal spot, the plurality of closely packed lenslets having an average equivalent circular diameter ECD avg and an average focal length f avg , ECD avg /f avg being in a range from about 0.05 to about 0.20, at least 90% of the lenslets in the plurality of closely packed lenslets having a nearest neighbor focal spot distance of less than about 30 micrometers, less than about 30% of the second structured major surface having a slope magnitude that is greater than about 5 degrees.

10. The optical film of claim 9 , wherein at least 90% of the second structured major surface is covered by the lenslets.

11. The optical film of claim 9 , wherein less than about 20% of the second structured major surface has a slope magnitude that is greater than about 5 degrees.

12. The optical film of claim 9 , wherein at least 80% of the lenslets in the plurality of lenslets have an equivalent circular diameter ECD that is less than about 27 micrometers.

13. The optical film of claim 9 , wherein at least 90% of the lenslets in the plurality of lenslets have a nearest neighbor focal spot distance that is less than about 25 micrometers.

14. The optical film of claim 9 , wherein the second structured major surface has an optical haze in a range from about 3% to about 25%.

15. An optical film, comprising:
a first structured major surface comprising a plurality of linear prisms extending along a same first direction; and
an opposing second structured major surface comprising a plurality of closely packed lenslets, each lenslet having a largest lateral dimension D, the plurality of closely packed lenslets having an average largest lateral dimension D avg , D avg being less than about 50 micrometers, at least 90% of the lenslets in the plurality of closely packed lenslets having a nearest neighbor focal spot distance of less than about 30 micrometers, less than about 30% of the second structured major surface having a slope magnitude that is greater than about 5 degrees.

16. The optical film of claim 15 , wherein at least 90% of the second structured major surface is covered by the lenslets.

17. The optical film of claim 15 , wherein less than about 20% of the second structured major surface has a slope magnitude that is greater than about 5 degrees.

18. The optical film of claim 15 , wherein at least 80% of the lenslets in the plurality of lenslets have an equivalent circular diameter ECD that is less than about 27 micrometers.

19. The optical film of claim 15 , wherein at least 90% of the lenslets in the plurality of lenslets have a nearest neighbor focal spot distance that is less than about 25 micrometers.

20. The optical film of claim 15 , wherein the second structured major surface has an optical haze in a range from about 3% to about 25%.

Assignees

• 3M Innovative Properties Co

Inventors

• Boyd Gary T

Classifications

• G02B6/0051

  Diffusing sheet or layer · CPC title

• G02B3/0043 Primary

  Inhomogeneous or irregular arrays, e.g. varying shape, size, height · CPC title

• G02B5/0221

  the surface having an irregular structure (G02B5/0226 takes precedence) · CPC title

• G02B5/0231

  the surface having microprismatic or micropyramidal shape (macroscopic prism arrays G02B5/045) · CPC title

• G02B5/0278

  used in transmission · CPC title