Diffuser for LED light sources

• US 8,981,405 B2
• Filed: 04/01/2013
• Issued: 03/17/2015
• Est. Priority Date: 10/24/2007
• Status: Active Grant

• Current Assignee: Switch Bulb Company, Inc.
• Original Assignee: Switch Bulb Company, Inc.
• Inventors: Lenk, Carol
• Primary Examiner(s): Lee, Eugene
• Application Number:
  US13/854,730
• Publication Number:
  US 20130214313A1
• Time in Patent Office: 715 Days
• Field of Search: 257/98
• US Class Current: 257/98
• CPC Class Codes: F21V 17/04 the fastening being onto or by the light source
• CPC Class Codes: F21V 17/06 the fastening being onto or by the lampholder
• CPC Class Codes: F21V 29/74 with fins or blades
• CPC Class Codes: F21V 29/763 the planes containing the fins or blades having the direction of the light emitting axis
• CPC Class Codes: F21V 3/00 Globes; Bowls; Cover glasses with refracting properties F21V5/00; with reflecting properties F21V7/00; characterised by cooling arrangements F21V29/506
• CPC Class Codes: F21V 5/00 Refractors for light sources characterised by cooling arrangements F21V29/504
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: G02B 5/0242 by means of dispersed particles
• CPC Class Codes: G02B 5/0278 used in transmission
• CPC Class Codes: H01L 33/58 Optical field-shaping elements

Abstract

An LED light source is described. The light source includes an LED and a diffuser. The LED emits a light having a dominant wavelength. The diffuser includes a filler material, which includes particles. The mean diameter of the particles is at least as large as the dominant wavelength of the light emitted by the LED. The particles are configured to scatter the light emitted by the LED.

Claims

1. An LED light source comprising:

at least one LED configured to emit a light, wherein the light has a dominant wavelength;

a diffuser; and

wherein the diffuser comprises a sealed panel having a first side configured to receive the light emitted by the at least one LED and a second side configured to emit light,

wherein a filler material is disposed between the first side and the second side of the sealed panel,

wherein the filler material is a fluid or gel,

wherein the filler material comprises particles,

wherein the mean diameter of the particles is at least as large as the dominant wavelength, and

wherein the particles are configured to scatter the light emitted by the at least one LED.

2. The LED light source of claim 1, wherein:

the diffuser comprises a first area with a first density of the filler material and a second area with a second density of the filler material; and

the first density is not the same as the second density.

3. The LED light source of claim 1, wherein:

the diffuser comprises a first area with a first density of the particles and a second area with a second density of the particles; and

the first density is not the same as the second density.

4. The LED light source of claim 1, wherein the particles comprise alumina trihydrate.

5. The LED light source of claim 1, wherein the at least one LED is a blue or ultraviolet LED without a phosphor, and the filler material contains at least one phosphor.

6. The LED light source of claim 1, wherein the filler material is a hydrogel.

7. The LED light source of claim 1, wherein the particles have been coated with inorganic particles.

8. An LED light source comprising:

at least one LED configured to emit a light, wherein the light has a dominant wavelength;

a diffuser; and

wherein the diffuser comprises a poly(acrylamide) hydrogel including particles, and a sealed panel having a first side configured to receive the light emitted by the at least one LED and a second side configured to emit light,

wherein a filler material is disposed between the first side and the second side of the sealed panel,

wherein the filler material is a poly(acrylamide) hydrogel,

wherein the filler material comprises particles,

wherein the mean diameter of the particles is at least as large as the dominant wavelength, and

wherein the particles are configured to scatter the light emitted by the at least one LED.

9. The LED light source of claim 8, wherein:

the diffuser comprises a first area with a first density of the particles and a second area with a second density of the particles; and

the first density is not the same as the second density.

10. The LED light source of claim 8, wherein the particles comprise alumina trihydrate.

11. The LED light source of claim 8, wherein the at least one LED is a blue or ultraviolet LED without a phosphor, and the poly(acrylamide) hydrogel contains at least one phosphor.

12. The LED light source of claim 8, wherein the particles have been coated with inorganic particles.

13. An LED light source comprising:

at least one LED configured to emit a light, wherein the light has a dominant wavelength;

a diffuser; and

wherein the diffuser comprises a sealed panel having a first side configured to receive the light emitted by the at least one LED and a second side configured to emit light,

wherein a filler material is disposed between the first side and the second side of the sealed panel,

wherein the filler material is a hydrocarbon-based oil,

wherein the filler material comprises particles,

wherein the mean diameter of the particles is at least as large as the dominant wavelength, and

wherein the particles are configured to scatter the light emitted by the at least one LED.

14. The LED light source of claim 13, wherein the diffuser further comprises a surfactant.

15. The LED light source of claim 13, wherein:

the diffuser comprises a first area with a first density of the hydrocarbon-based oil and a second area with a second density of the hydrocarbon-based oil; and

the first density is not the same as the second density.

16. The LED light source of claim 13, wherein:

the diffuser comprises a first area with a first density of the particles and a second area with a second density of the particles; and

the first density is not the same as the second density.