Light diffusing optical fibers for emitting white light

Patent metadata

Field	Value
Publication number	US-11059747-B2
Application number	US-201816496625-A
Country	US
Kind code	B2
Filing date	Mar 28, 2018
Priority date	Mar 28, 2017
Publication date	Jul 13, 2021
Grant date	Jul 13, 2021

Abstract

A light diffusing optical fiber includes a glass core, a cladding, a phosphor layer surrounding the cladding, and a plurality of scattering structures positioned within the glass core, the cladding, or both. The phosphor layer includes two or more phosphors and is configured to convert guided light diffusing through the phosphor layer into emission light such that the color of the emission light has a chromaticity within a u′-v′ chromaticity region on a CIE 1976 chromaticity space defined by: a first u′-v′ boundary line and a second u′-v′ boundary line that extend parallel to a planckian locus at a distance of ±0.02 Duv from the planckian locus, a third u′-v′ boundary line that extends along an isothermal line for a correlated color temperature of about 2000 K, and a fourth u′-v′ boundary line that extends along an isothermal line for a correlated color temperature of about 10000 K.

First claim

What is claimed is:

1. A light diffusing optical fiber comprising:
a glass core;
a cladding surrounding the glass core;
a phosphor layer surrounding the cladding; and
a plurality of scattering structures positioned within the glass core, the cladding, or both the glass core and the cladding, wherein:
the plurality of scattering structures are configured to scatter guided light toward the phosphor layer of the light diffusing optical fiber such that a portion of the guided light diffuses through the phosphor layer along a diffusion length of the light diffusing optical fiber, and
the phosphor layer comprises two or more phosphors and is configured to convert guided light diffusing through the phosphor layer into emission light such that the color of the emission light comprises a chromaticity within a u′-v′ chromaticity region on a CIE 1976 chromaticity space defined by:
a first u′-v′ boundary line that extends parallel to a planckian locus at a distance of 0.02 Duv from the planckian locus;
a second u′-v′ boundary line that extends parallel to the planckian locus at a distance of −0.02 Duv from the planckian locus;
a third u′-v′ boundary line that extends between the first u′-v′ boundary line and the second u′-v′ boundary line along an isothermal line for a correlated color temperature of about 2000 K; and

a fourth u′-v′ boundary line that extends between the first u′-v′ boundary line and the second u′-v′ boundary line along an isothermal line for a correlated color temperature of about 10000 K;

wherein the phosphor layer comprises a buffer tube.

2. The light diffusing optical fiber of claim 1 , wherein the light diffusing optical fiber emits light having an intensity along the diffusion length that does not vary by more than about 40%.

3. An illumination system comprising the light diffusing optical fiber of claim 1 optically coupled to a light output device comprising a light source.

4. The illumination system of claim 3 , wherein light output by the light source and propagating along the light diffusing optical fiber comprises a wavelength from about 300 nm to about 520 nm.

5. The light diffusing optical fiber of claim 1 , wherein the two or more phosphors comprise a red phosphor and a yellow phosphor.

6. The light diffusing optical fiber of claim 1 , wherein the two or more phosphors comprise phosphorescent or fluorescent materials.

7. The light diffusing optical fiber of claim 6 , wherein the phosphorescent or fluorescent materials comprise Ce-YAG, Nd-YAG, nitride, orthosilicate, sulfoselenide, quantum dots, nanoparticles, or a combination thereof.

8. The light diffusing optical fiber of claim 1 , wherein:
the phosphor layer further comprises a polymer base material; and
the two or more phosphors are disposed within the polymer base material.

9. A light diffusing optical fiber comprising:
a glass core;
a cladding surrounding the glass core;
a phosphor layer surrounding the cladding; and
a plurality of scattering structures positioned within the glass core, the cladding, or both the glass core and the cladding, wherein:
the plurality of scattering structures are configured to scatter guided light toward the phosphor layer of the light diffusing optical fiber such that a portion of the guided light diffuses through the phosphor layer along a diffusion length of the light diffusing optical fiber, and
the phosphor layer comprises two or more phosphors and is configured to convert guided light diffusing through the phosphor layer into emission light such that the color of the emission light comprises a chromaticity within an x-y chromaticity region on a CIE 1931 chromaticity space defined by:
a first x-y boundary line that extends from a first x-y chromaticity point located between about (0.15, 0.0) and (0.25, 0.0) and a second x-y chromaticity point located at about (0.4, 0.6); and
a second x-y boundary line that extends from the first x-y chromaticity point and a third x-y chromaticity point located at about (0.6, 0.4);

wherein a scattering material is disposed within the phosphor layer, and wherein the phosphor layer comprises a buffer tube.

10. The light diffusing optical fiber of claim 9 , wherein the two or more phosphors comprise a red phosphor and a yellow phosphor.

11. The light diffusing optical fiber of claim 9 , wherein the two or more phosphors comprise phosphorescent or fluorescent materials.

12. The light diffusing optical fiber of claim 11 , wherein the phosphorescent or fluorescent materials comprise Ce-YAG, Nd-YAG, nitride, orthosilicate, sulfoselenide, quantum dots, nanoparticles, or a combination thereof.

13. The light diffusing optical fiber of claim 9 , wherein the chromaticity of the emission light is located within the x-y chromaticity region defined by the first x-y boundary line and the second x-y boundary line located on the CIE 1931 chromaticity space for all viewing angles from about 15° to about 170° relative to a propagation direction of the guided light.

14. The light diffusing optical fiber of claim 9 , wherein the light diffusing optical fiber emits light having an intensity along the diffusion length that does not vary by more than about 20%.

15. An illumination system comprising the light diffusing optical fiber of claim 9 optically coupled to a light output device comprising a light source.

16. The illumination system of claim 15 , wherein light output by the light source and propagating along the light diffusing optical fiber comprises a wavelength from about 300 nm to about 520 nm.

17. A light diffusing optical fiber comprising:
a first end, a second end opposing the first end,
a length between the first end and the second end,
a glass core extending along the length; and
a cladding surrounding at least a portion of the glass core;
a polymer layer surrounding the cladding; and
wherein the fiber is configured to scatter a guided light propagating along the light diffusing optical fiber toward an outer surface of the light diffusing optical fiber such that a portion of the guided light diffuses through the polymer layer along a diffusion length of the light diffusing optical fiber;
wherein, after the light diffusing fiber is aged by placing the fiber in a chamber having a temperature of 85° C. and 85% relative humidity for 100 hours, and after a light source is optically coupled to the first end, the light diffusing fiber exhibits any one of:
an optical loss that changes about 20% or less,
a scattering efficiency in a spectral range from 420 nm to 800 nm that changes about 10% or less, and
a brightness at any given portion of the fiber along the length that changes less than 25%;

wherein the polymer layer comprises two or more phosphors; and
wherein the polymer layer comprises a buffer tube.

18. The light diffusing optical fiber of claim 17 comprises a plurality of scattering structures positioned within the glass core, the cladding, or both the glass core and the cladding, wherein the plurality of scattering structures are configured to scatter guided light toward the outer surface of the light diffusing optical fiber such that a portion of the guided light diffuses through the polymer layer along a diffusion length of the light diffusing optical fiber that is converted into emission light having a color point in Duv units in the CIE 1976 chromaticity space, wherein after aging the color point shifts about 0.02 or less.

19. The light diffusing optical fiber of claim 17 , wherein the polymer layer configured to convert guided light diffusing thr

Assignees

• Corning Inc

Inventors

• Logunov Stephan Lvovich
• Ocampo Manuela

Classifications

• G02B6/001

  the light being emitted along at least a portion of the lateral surface of the fibre · CPC title

• G02B6/0003 Primary

  the light guides being doped with fluorescent agents · CPC title

• G02B6/03694

  Multiple layers differing in properties other than the refractive index, e.g. attenuation, diffusion, stress properties · CPC title

• G02B6/023

  having different index layers arranged around the core for guiding light by reflection, i.e. 1D crystal, e.g. omniguide · CPC title

• G02B6/02366

  Single ring of structures, e.g. "air clad" · CPC title