Polarizing lighting systems

Patent metadata

Field	Value
Publication number	US-9529228-B2
Application number	US-201113883701-A
Country	US
Kind code	B2
Filing date	Nov 6, 2011
Priority date	Nov 5, 2010
Publication date	Dec 27, 2016
Grant date	Dec 27, 2016

Abstract

An optically active structure ( 100 ) is provided, comprising at least two different groups (G 1 , G 2 ) of optically active nanorods ( 104 A, 104 B). The groups of nanorods differ from one another in at least one of wavelength and polarization of light emitted thereby in response to pumping light. The nanorods of the same group are homogeneously aligned with a certain axis of alignment being substantially parallel or substantially perpendicular to an axis of alignment of the nanorods of at least one other group, such that the nanorods of said at least two groups have one or two axes of alignment. The optically active structure is used as color polarized light source for displays.

First claim

The invention claimed is:

1. An optically active structure comprising:
a plurality of optically active nanorods formed by the nanorods arranged in at least two groups differing from one another in at least one of wavelength, and axis of alignment and thereby polarization of light emitted therefrom in response to pumping light, such that the nanorods of the same group are homogeneously aligned with a certain first axis of alignment substantially parallel or substantially perpendicular to a second axis of alignment of the nanorods of at least one other group, such that said plurality of nanorods of said at least two groups have one or two axes of alignment being substantially parallel or substantially perpendicular to one another; and
at least one light extracting feature configured to preserve said polarization of the emitted light.

2. The structure of claim 1 , comprising the nanorods which emit light of substantially the same wavelength and are oriented along the two perpendicular axes of alignment thereby producing light of orthogonal polarizations.

3. The structure of claim 1 , comprising at least one region thereof which contains a mixture of the homogeneously aligned nanorods of said at least two groups, and nanorods of said at least two groups being configured for emitting light of at least two different wavelengths, respectively.

4. The structure of claim 1 , comprising at least one pair of spaced-apart regions, containing the nanorods of the two groups respectively.

5. The structure of claim 1 , comprising an array of regions arranged along at least one axis in a spaced-apart relationship, each two adjacent regions aligned along said at least one axis containing the nanorods of the different groups.

6. The structure of claim 1 , wherein said nanorods are arranged in at least one layer.

7. The structure of claim 1 , wherein the nanorods are embedded in a carrier.

8. The structure of claim 1 , wherein the nanorods are deposited on a substrate carrier.

9. The structure of claim 1 , wherein the nanorods are made of one or more semiconductor materials.

10. The structure of claim 1 , wherein the nanorods have an elongated geometry with an aspect ratio of at least 1.8.

11. The structure of claim 1 , wherein the nanorods have a core-shell configuration.

12. The structure of claim 1 , wherein the nanorods are configured as seeded rods.

13. A lighting device comprising the optically active structure of claim 1 , and a pumping light source.

14. A lighting device configured as a colored display device comprising the optically active structure of claim 1 , a pumping light source for exciting said optically active structure and a pixel arrangement exposed to light emitted by said optically active structure.

15. The structure of claim 1 , wherein said at least one light extracting feature comprises at least one of reflective, diffusing and refractive structures or interfaces configured to preserve polarization of light passing therethrough.

16. The structure of claim 7 , wherein the carrier is optically transparent for the pumping light and emitted light.

17. The structure of claim 7 , wherein the carrier with the embedded nanorods has a thickness ranging between 10 micrometers and 1 millimeter.

18. The structure of claim 7 , wherein said at least one light extracting feature comprises a light director interfacing with a side of said carrier and is configure to direct emitted light towards a desired direction.

19. The structure of claim 7 , wherein said carrier is selected from at least one of polymer, epoxy, silicone, glass and a hybrid of silicone and epoxy.

20. The structure of claim 8 , wherein the substrate carrier is optically transparent for the pumping light and emitted light.

21. The structure of claim 8 , wherein the nanorods deposited on said substrate carrier form a layer of nanorods having a thickness ranging between 10 nanometers and 2 micrometer.

22. The structure of claim 12 , wherein a seed in the seeded nanorod has a spherical or rod-like geometry.

23. The lighting device of claim 13 , wherein the optically active structure is configured and operable as a back lighting unit.

24. The lighting device of claim 13 , configured to direct the emitted light along a first general direction of propagation, the device comprising a light source of said pumping light defining a second general direction of propagation of the pumping light towards the optically active structure, wherein said second direction is along an axis intersecting with an axis defined by said first general direction of propagation of the output light.

25. The lighting device of claim 13 , comprising at least one light deflecting surface located in an optical path of the light emitted by the optically active structure.

26. The lighting device of claim 13 , comprising at least one light refracting surface located in an optical path of the light emitted by the optically active structure.

27. An optically active structure, comprising at least two different groups of optically active nanorods differing in at least wavelength of light emitted therefrom in response to the pumping light, said at least two groups of nanorods being located, respectively, in at least two layers spaced apart along a predetermined axis defined by general direction of propagation of emitted light, thereby forming a cascaded arrangement of the optically active structure; the nanorods of the same group being homogeneously aligned with a certain axis of alignment being substantially parallel or substantially perpendicular to an axis of alignment of the nanorods of at least one other group, such that the nanorods of said at least two groups have one or two axes of alignment.

28. The structure of claim 27 , wherein said at least two groups of nanorods are arranged in said at least two layers such that the nanorods emitting light of relatively shorter wavelength of said at least two wavelengths of emitted light are located downstream of the nanorods emitting light of relatively longer wavelength, with respect to a direction of propagation of the pumping light.

29. An optically active structure comprising:
a plurality of optically active nanorods formed by nanorods of two groups, the nanorods of the same group being homogeneously aligned with an axis of alignment being substantially perpendicular to an axis of alignment of the nanorods of the other group thereby emitting orthogonally polarized light; and
at least one light extracting feature configured to preserve said polarization of the emitted light;
thereby providing said optically active structure emitting light of two orthogonally polarizations.

30. The structure of claim 29 , wherein the nanorods comprise nanorods emitting light of at least two different wavelengths.

31. The structure of claim 29 , wherein said two groups of nanorods are located in at least two spaced-apart regions, such that each region comprises the nanorods of one group and is adjacent to at least one region comprising the nanorods of the other group.

32. An optically active structure comprising:
a plurality of optically active nanorods formed by at least two groups of the nanorods differing from one another in a wavelength of light emitted therefrom in response to pumping light, said plurality of optically active nanorods bei

Assignees

• Banin Uri
• Arbell Hagai
• Yissum Res Dev Co
• Qlight Nanotech Ltd

Inventors

• Banin Uri
• Arbell Hagai

Classifications

• G02F1/133617 Primary

  Illumination with ultraviolet light; Luminescent elements or materials associated to the cell · CPC title

• G02F1/133621

  providing coloured light (G02F1/133617, G02F1/133533 take precedence) · CPC title

• G02F1/1336 Primary

  Illuminating devices · CPC title

• G02F2203/34

  Colour display without the use of colour mosaic filters · CPC title

• G02F1/13362 Primary

  providing polarized light, e.g. by converting a polarisation component into another one · CPC title