Granted Patent B2

US 7,265,488 · App. 10/954,399 · Granted Sep 4, 2007

Abstract

Claims (25)

1. A method for generating visible light, comprising:

a) generating primary light using a light-emitting semiconductor device;

b) receiving the primary light with a first body of wavelength converting material;

c) absorbing a first portion of the primary light by a plurality of phosphor particles in the first body of wavelength converting material and emitting secondary light while transmitting a second portion of the primary light;

d) receiving the secondary light and the second portion of the primary light with a second body of wavelenoth converting material;

e) absorbing the second portion of the primary light by a plurality of phosphor nano-particles in the second body of wavelength converting material and emitting tertiary light; and

f) transmitting the secondary light through the second body of wavelength converting material;

wherein the secondary light and the tertiary light combine to form white light.

2. The light-emitting device of claim 1 , wherein the larger phosphor particles have a mean size greater than 5 μm, and the phosphor nano-particles have a mean size less than 0.1 μm.

3. The light-emitting device of claim 1 , wherein the larger phosphor particles have a mean size greater than 5 μm, and the phosphor nano-particles have a mean size less than 0.1 μm.

4. The light-emitting device of claim 1 , wherein the phosphor nano-particles comprise quantum dots.

5. The light-emitting device of claim 1 , wherein the primary light is ultraviolet light.

6. The light-emitting device of claim 1 , wherein the light-emitting semiconductor device is selected form the group consisting of an LED and a laser diode.

7. The light emitting device of claim 1 , wherein the light-emitting semiconductor device is a blue LED.

8. A light emitting device comprising:

A light-emitting semiconductor device operable to emit a primary light having an ultraviolet component;

a first coating converting material applied to a surface of the light-emitting semiconductor device and operable to receive at least a portion of the primary light and emit a secondary light in response; and

a second coating of wavelength converting material applied to the first coating of wavelength converting material and operable to reduce radiation of the primary light and to transmit the secondary light;

wherein the first coating of wavelength converting material comprises phosphor particles having a mean size greater than 2 μm, and the second coating of wavelength converting material comprises phosphor nano-particles having a mean size less than 1 μm, the second coating of wavelength converting material being operable to convert the primary light into tertiary light, the second and tertiary lights combining to form white light.

9. The light-emitting device of claim 8 , wherein the larger phosphor particles have a mean size greater than 5 μm, and the phosphor nano-particles have a mean size less than 0.1 μm.

10. The light-emitting device of claim 8 , wherein the larger phosphor particles have a mean size greater than 5 μm, and the phosphor nano-particles have a mean size less than 0.1 μm.

11. The light-emitting device of claim 8 , wherein the phosphor nano-particles comprise quantum dots.

12. The light-emitting device of claim 8 , wherein the primary light is ultraviolet light.

13. The light-emitting device of claim 8 , wherein the light-emitting semiconductor device is selected form the group consisting of an LED and a laser diode.

14. The light emitting device of claim 8 , wherein the light-emitting semiconductor device is a blue LED.

Assignments (8)