Optical films and methods of making the same

• US 8,765,360 B2
• Filed: 12/09/2010
• Issued: 07/01/2014
• Est. Priority Date: 04/15/2004
• Status: Expired due to Term

• Current Assignee: Ushio Denki Kabushiki Kaisha (Ushio Incorporated)
• Original Assignee: Polarization Solutions, Llc
• Inventors: Wang, Jian Jim, Deng, Xuegong, Nikolov, Anguel N.
• Primary Examiner(s): ANGEBRANNDT, MARTIN J
• Application Number:
  US12/964,646
• Publication Number:
  US 20110279900A1
• Time in Patent Office: 1,300 Days
• Field of Search: None
• US Class Current: 430/321
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: G02B 1/113 using inorganic layer materials only
• CPC Class Codes: G02B 1/118 having sub-optical wavelength surface structures designed to provide an enhanced transmittance, e.g. moth-eye structures
• CPC Class Codes: G02B 5/18 Diffraction gratings holographic optical elements G02B5/32, G03H; integrally combined with optical fibres G02B6/02057; for coupling light guides G02B6/34; integrally combined with optical integrated light guides G02B6/12; grating systems G02B27/44
• CPC Class Codes: G02B 5/1809 with pitch less than or comparable to the wavelength
• CPC Class Codes: G02B 5/1857 using exposure or etching means, e.g. holography, photolithography, exposure to electron or ion beams
• CPC Class Codes: G02B 5/1866 Transmission gratings characterised by their structure, e.g. step profile, contours of substrate or grooves, pitch variations, materials G02B5/1809, G02B5/1828, G02B5/1833, G02B5/1838 and G02B5/1847 take precedence
• CPC Class Codes: G02B 5/3025 Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state G02B5/3008, G02B5/3016 take precedence
• CPC Class Codes: G02B 5/3083 Birefringent or phase retarding elements G02B5/3008, G02B5/3016 take precedence; systems for polarisation control G02B27/286; manufacturing phase modulating patterns by lithographic processes G03F7/001
• CPC Class Codes: G02F 1/13363 Birefringent elements, e.g. for optical compensation

Abstract

Films for optical use, articles containing such films, methods for making such films, and systems that utilize such films, are disclosed.

Claims

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 SiO₂, SiNx, Si, Al₂O₃, ZrO₂, Ta₂O₅, TiO₂, HfO₂, Nb₂O₅, and MgF₂.

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 SiO₂, SiNx, Si, Al₂O₃, ZrO₂, Ta₂O₅, TiO₂, HfO₂, Nb₂O₅, and MgF₂, 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 SiO₂, SiNx, Si, Al₂O₃, ZrO₂, Ta₂O₅, TiO₂, HfO₂, Nb₂O₅, and MgF₂.

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 SiO₂, SiNx, Si, Al₂O₃, ZrO₂, Ta₂O₅, TiO₂, HfO₂, Nb₂O₅, and MgF₂.

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.

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.

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

.