Light redirecting film having surface nano-nodules

1 . A light redirecting optical device comprising a polymeric film containing a light entry and a light exit surface and bearing on the light exit surface convex macrostructures that have a length, diameter, or other major dimension of at least 25 micrometers, wherein a major portion of the macrostructure surfaces is covered with nano-nodules having an average maximum cord length in a plane perpendicular to the direction of light travel of less than 1200 nm.

2 . The device of claim 1 wherein the nano-nodules have an average diameter size between 400 and 1200 nm.

3 . The device of claim 1 wherein the nano-nodules have an average diameter size between 600 and 1000 nm.

4 . The device of claim 1 wherein the nano-nodules are concave.

5 . The device of claim 1 wherein the nano-nodules are convex.

6 . The device of claim 1 wherein the macro-structures comprise a prism.

7 . The device of claim 1 wherein the nano-nodules comprise polymer

8 . The device of claim 1 wherein the nano-nodules are integral to the macro-structures.

9 . The device of claim 1 wherein the macro-structures comprise individual optical elements.

10 . The device of claim 1 wherein the macrostructures have a height to width aspect ratio between 0.5 and 5.0.

11 . The device of claim 1 wherein the optical gain of the optical film is between 1.15 and 1.30.

12 . The device of claim 1 wherein the nano-nodules are integral to the macro-structures and cover between 40 and 60% of the surface area of the macrostructures.

13 . The device of claim 1 wherein the nano-nodules are randomly distributed over the surface of the macro-structures and the diameter of the nano-nodules overlap by at least 5%.

14 . The device of claim 1 wherein the nano-nodules cover greater than 95% of the macro-structure surface.

15 . The device of claim 1 wherein the nano-nodules cover between 65 and 85% of the macro-structure surface.

16 . The device of claim 1 further comprising nano-nodules on a surface opposite the light exit surface.

17 . An optical film comprising a film bearing convex macrostructures on the light exit surface wherein the macrostructures have a length, diameter, or other major dimension of at least 25 micrometers and wherein the surfaces of the macrostructures exhibit a R a value of not more than 1200 nanometers.

18 . The optical film of claim 17 wherein the R a value of the surface of the macro-structures is between 600 and 1000 nanometers.

19 . The optical film of claim 17 wherein the macrostructures have a height to width aspect ratio between 0.5 and 5.0.

20 . The optical film of claim 17 wherein the macrostructures have a repeating pattern.

21 . The optical film of claim 17 wherein the macrostructures have a length, diameter, or other major dimension of at least 100 micrometers.

22 . An optical film comprising a film bearing convex or concave macrostructures on the light exit surface wherein the macrostructures have a length, diameter, or other major dimension of at least 25 micrometers and wherein the surfaces of the macrostructures exhibit an R a value low enough to provide a reduction in on-axis optical gain of at least 25% compared to the same macrostructure arrangement without the surface roughness.

23 . The optical film of claim 22 wherein the reduction in optical gain is between 37 and 63%.

24 . The optical film of claim 22 wherein a major portion of the macrostructure surfaces being covered with nano-nodules having an average maximum cord length in a plane perpendicular to the direction of light travel of less than 1200 nm.

25 . The optical film of claim 22 wherein the macrostructures have a height to width aspect ratio between 0.5 and 5.0.

26 . A process for making a metal form comprising a surface having a morphology of macrostructures comprising the steps of electro-mechanically engraving on the surface of the metal form and plating the surface of the metal form to provide a metallic nano-nodule coating on the surface of the macrostructures.

27 . The process of claim 26 wherein the macrostructure has an apex angle between 88 and 92 degrees.

28 . The process of claim 26 wherein the metallic coating comprises thin dense chrome.

29 . The process of claim 26 wherein the thickness of the metallic nano-nodule coating is between 0.25 and 4.0 micrometers.

30 . The process of claim 26 wherein the form comprises metallic copper.

31 . The process of claim 26 wherein the metallic nano-nodule coating has a mechanical hardness between 70 to 80 Rockwell C.