Transparent polarized light-emitting device

• US 8,637,331 B2
• Filed: 08/27/2012
• Issued: 01/28/2014
• Est. Priority Date: 10/17/2008
• Status: Expired due to Fees

• Current Assignee: Bloominescence, LLC
• Original Assignee: Bloominescence, LLC
• Inventors: Shanks, Mark
• Primary Examiner(s): NGO, NGAN V
• Application Number:
  US13/595,771
• Publication Number:
  US 20120315714A1
• Time in Patent Office: 519 Days
• Field of Search: 438/27, 438/29, 257/E33.068, 257/E21.527
• US Class Current: 438/27
• CPC Class Codes: C09K 19/2028 containing additionally a linking group other than -COO- or -OCO-, e.g. -CH2-CH2-, -CH=CH-, -C=C-; containing at least one additional carbon atom in the chain containing -COO- or -OCO- groups, e.g. -COO-CH*-CH3
• CPC Class Codes: C09K 2019/0481 Phenylene substituted in meta position
• CPC Class Codes: H05B 33/22 characterised by the chemical or physical composition or the arrangement of auxiliary dielectric or reflective layers
• CPC Class Codes: H05B 33/28 of translucent electrodes
• CPC Class Codes: H10K 2102/3031 Two-side emission, e.g. transparent OLEDs [TOLED]
• CPC Class Codes: H10K 50/115 comprising active inorganic nanostructures, e.g. luminescent quantum dots
• CPC Class Codes: H10K 50/828 Transparent cathodes, e.g. comprising thin metal layers
• CPC Class Codes: H10K 50/856 comprising reflective means
• CPC Class Codes: H10K 50/868 Arrangements for polarized light emission H10K50/86 takes precedence
• CPC Class Codes: H10K 59/80524 Transparent cathodes, e.g. comprising thin metal layers
• CPC Class Codes: H10K 59/878 comprising reflective means
• CPC Class Codes: H10K 59/8793 Arrangements for polarized light emission H10K59/8791 takes precedence

Abstract

A polarized light-emitting device is fabricated by a method that includes forming a radiation-emitting layer. The radiation-emitting layer includes a radiation-emitting material that emits radiation having a wavelength included in an emission wavelength band. The radiation-emitting material is disposed between a transparent anode and a transparent cathode. An optically active reflective layer is disposed on the polarized light-emitting device. The optically active reflective layer is configured to reflect radiation having a wavelength included in a reflection wavelength band of the optically active reflective layer. The reflection wavelength band of the optically active reflective layer is adjusted to at least partially encompass the emission wavelength band of the radiation-emitting layer.

Claims

1. A method of fabricating a polarized light-emitting device, the method comprising:

forming a radiation-emitting layer, the radiation-emitting layer comprising a radiation-emitting material configured to emit radiation having a wavelength included in an emission wavelength band and being disposed between a transparent anode and a transparent cathode;

depositing an optically active reflective layer on the polarized light-emitting device, the optically active reflective layer being configured to reflect radiation having a wavelength included in a reflection wavelength band of the optically active reflective layer; and

adjusting the reflection wavelength band of the optically active reflective layer to at least partially encompass the emission wavelength band of the radiation-emitting layer.

2. The method of claim 1, wherein the radiation-emitting material comprises an organic light-emitting layer.

3. The method of claim 1, wherein the optically active reflective layer comprises a layer of glass-forming chiral nematic liquid crystals (GLC).

4. The method of claim 3, wherein adjusting the reflection wavelength band of the optically active reflective layer comprises:

heating the layer of glass-forming chiral nematic liquid crystals above a glass transition temperature (Tg) and near a critical point (Tc) of the glass-forming chiral nematic liquid crystals;

irradiating the optically active reflective layer with electromagnetic radiation for a time duration sufficient to alter the reflection wavelength band of the optically active reflective layer to at least partially encompass the emission wavelength band of the radiation-emitting material;

and cooling the optically active reflective layer to a temperature below the glass transition temperature (Tg).

5. The method of claim 4, wherein irradiating the optically active reflective layer comprises irradiating the optically active reflective layer with ultraviolet (UV) radiation.

6. The method of claim 3, wherein adjusting the reflection wavelength band of the optically active reflective layer comprises adjusting a molecular composition of the layer of glass-forming chiral nematic liquid crystals.

7. The method of claim 3, wherein:

the optically active reflective layer comprises a first GLC film made of a right-handed glassy cholesteric material, and a second GLC film made of a left-handed glassy cholesteric material, the second GLC film being adjacent to the first GLC film, and

adjusting the reflection wavelength band of the optically active reflective layer comprises adjusting a molecular ratio of the right-handed glassy cholesteric material to the left-handed glassy cholesteric material.

8. The method of claim 7, wherein, to adjust the reflection band of the optically active reflective layer, the molecular composition of both the first GLC film and the second GLC film are adjusted.

9. The method of claim 1, wherein adjusting the reflection wavelength band of the optically active reflective layer results in changing a width of the reflection wavelength band.

10. The method of claim 1, wherein the radiation-emitting material comprises a quantum dot layer.

11. The method of claim 1, further comprising:

depositing a second optically active reflective layer on the optically active reflective layer, the second optically active reflective layer and the optically active reflective layer having opposite chirality; and

adjusting the reflection wavelength band of the second optically active reflective layer to at least partially encompass the emission wavelength band of the light-emitting layer.

12. The method of claim 11, wherein the optically active reflective layers are deposited consecutively, the reflection wavelength band of the second optically active reflective layer is adjusted on a separate substrate, and the optically active reflective layer is bonded to one side of the polarized light emitting device after the reflection wavelength band of the second optically active reflective layer is adjusted.

13. The method of claim 1, wherein the optically active layer is deposited on a transparent substrate.

14. The method of claim 13, wherein the transparent substrate is located between the optically active reflective layer and the light-emitting layer.

15. The method of claim 1,

wherein the optically active reflective layer comprises a holographic optical recording material layer;

and

wherein adjusting the reflection wavelength band of the optically active reflective layer comprises;

irradiating a holographic optical recording material layer with two or more collimated object beams that successively interfere with a common collimated reference beam to generate several multiplexed reflection holograms on the holographic optical recording material layer,

wherein the object beams are circularly polarized, have the same chirality, have a specified wavelength to at least partially encompass the emission wavelength band of the radiation-emitting layer, and are incident to the holographic optical recording material layer at a series of angles chosen to maximize the reflection efficiency over a desired field of view at the specified wavelength.

16. The method of claim 1, wherein adjusting the reflection wavelength band of the optically active reflective layer results in changing the incident angles at which the reflection wavelength band is achieved.

17. The method of claim 1,

wherein the optically active reflective layer has a chirality, such that the optically active reflective layer is configured to reflect radiation having a chirality matching the chirality of the optically active reflective layer;

and

and wherein the method further comprises adhering a pre-fabricated broad-band circular polarization filter between the light-emitting layer and the optically active reflective layer, wherein the circular polarization filter has a chirality that is opposite the chirality of the optically active reflective filter.

18. The method of claim 1, further comprising:

adhering a prefabricated radiation-collimating layer between the radiation-emitting layer and the optically active reflective layer, wherein the radiation-collimating layer has an optical property of limiting the direction of radiation that is emitted by the radiation-emitting layer to an angle less than 40 degrees from normal relative to a surface of the polarized light emitting device.

19. The method of claim 18 wherein the prefabricated radiation-collimating layer is one of a photonic crystal composite film or a micro-louver film.

20. A method of fabricating a polarized light-emitting device, the method comprising:

forming a radiation-emitting layer, the radiation-emitting layer comprising a radiation-emitting material configured to emit radiation having a wavelength included in an emission wavelength band and being disposed between a transparent anode and a transparent cathode;

depositing an optically active reflective layer on the polarized light-emitting device, the optically active reflective layer being configured to reflect radiation having (i) a wavelength included in a reflection wavelength band of the optically active reflective layer and (ii) a chirality matching a chirality of the optically active reflective layer; and

adjusting the reflection wavelength band of the optically active reflective layer to at least partially encompass the emission wavelength band of the radiation-emitting layer.