Optical films and methods of making the same
View Patent ↗Films for optical use, articles containing such films, methods for making such films, and systems that utilize such films, are disclosed.
1. An optical retarder having a retardation film comprising:
a grating having a period of less than 0.5λ, where λ is between 400 and 700 nm, inclusive;
a grating material having an index of refraction of n g at λ;
a fill material disposed by atomic layer deposition between and conformally coating adjacent lines of the grating material, the fill material having an index of refraction n f at λ, and n g differs from n f by more than zero but less than 1;
wherein at least one trench in which the fill material is disposed is at least 90% filled; and
the period, grating material and fill material chosen such that the film is form birefringent at λ.
2. The retarder of claim 1 , wherein the fill material in the trench contains a nanolaminate.
3. The retarder of claim 1 , wherein the fill material has a layer that comprises a material selected from the group consisting of SiO 2 , SiNx, Si, Al 2 O 3 , ZrO 2 , Ta 2 O 5 , TiO 2 , HfO 2 , Nb 2 O 5 , and MgF 2 .
4. The retarder of claim 1 , wherein the fill material has a first layer that comprises a first material selected from the group consisting of SiO 2 , SiNx, Si, Al 2 O 3 , ZrO 2 , Ta 2 O 5 , TiO 2 , HfO 2 , Nb 2 O 5 , and MgF 2 , and a second layer having a different composition from the first layer.
5. The retarder of claim 1 , wherein the fill material has at least one layer derived in situ from a precursor, the layer comprising a composition selected from the group consisting of SiO 2 , SiNx, Si, Al 2 O 3 , ZrO 2 , Ta 2 O 5 , TiO 2 , HfO 2 , Nb 2 O 5 , and MgF 2 .
6. The retarder of claim 1 , wherein the fill material has a refractive index of at least 1.3 at λ.
7. The retarder of claim 1 , wherein the fill material has a refractive index of at least 1.6 at λ.
8. The retarder of claim 1 , wherein the fill material has a refractive index of at least 2.0 at λ.
9. The retarder of claim 1 , wherein the grating material is selected from the group consisting of SiO 2 , SiNx, Si, Al 2 O 3 , ZrO 2 , Ta 2 O 5 , TiO 2 , HfO 2 , Nb 2 O 5 , and MgF 2 .
10. The retarder of claim 1 , wherein the grating material comprises a glass.
11. The retarder of claim 1 , wherein the grating material comprises a polymer.
12. The retarder of claim 1 , wherein the grating material comprises a semiconductor.
13. The retarder of claim 1 , wherein retarder has an optical retardation of at least 5 nm for light of wavelength λ propagating through the retarder.
14. The retarder of claim 1 , wherein retarder has an optical retardation of at least 10 nm for light of wavelength λ propagating through the retarder.
15. The retarder of claim 1 , wherein retarder has an optical retardation of at least 20 nm for light of wavelength λ propagating through the retarder.
16. The retarder of claim 1 , wherein retarder has an optical retardation of at least 50 nm for light of wavelength λ propagating through the retarder.
17. The retarder of claim 1 , wherein the at least one trench has a depth of at least 10 nm.
18. An optical retarder having a retardation film comprising:
a grating having a period of less than 0.5λ, where λ is between 150 and 2000 nm, inclusive;
a grating material having an index of refraction of n g at λ;
a fill material disposed by atomic layer deposition between and conformally coating adjacent lines of the grating material, the fill material having an index of refraction n f at λ, and n g differs from of by more than zero but less than 1;
wherein at least one trench in which the fill material is disposed is at least 90% filled; and
the period, grating material and fill material chosen such that the film is form birefringent at λ.
19. The retarder of claim 1 , wherein the at least one trench in which the fill material is disposed is at least 90% filled and less than 100% filled.
20. The retarder of claim 1 , wherein the at least one trench in which the fill material is disposed is 100% filled.