Light emitting device and fabricating method thereof

Patent metadata

Field	Value
Publication number	US-9722149-B2
Application number	US-201615008020-A
Country	US
Kind code	B2
Filing date	Jan 27, 2016
Priority date	May 30, 2005
Publication date	Aug 1, 2017
Grant date	Aug 1, 2017

Abstract

A light-emitting device includes a light-emitting element for emitting primary light, and a wavelength conversion unit for absorbing part of the primary light and emitting secondary light having a wavelength longer than that of the primary light, wherein the wavelength conversion unit includes plural kinds of phosphors having light absorption characteristics different from each other, and then at least one kind of phosphor among the plural kinds of phosphors has an absorption characteristic that can absorb the secondary light emitted from at least another kind of phosphor among the plural kinds of phosphors.

First claim

What is claimed is:

1. A light-emitting device, comprising:
a light-emitting element for emitting primary light; and
a wavelength conversion unit for absorbing part of the primary light and emitting secondary light having a wavelength longer than that of the primary light, wherein
said light-emitting element is formed of a gallium nitride-based semiconductor,
said wavelength conversion unit includes plural kinds of phosphors different in light absorption characteristic from each other that are dispersed into a transparent binder resin,
said primary light that said light-emitting element emits has a peak wavelength in the range from 400 nm to 500 nm,
said secondary light that at least one kind of phosphors among the plural kinds of phosphors emits has a peak wavelength in the range from 500 nm to 550 nm,
said secondary light that at least one other kind of phosphors among the plural kinds of phosphors emits has a peak wavelength in the range from 600 nm to 650 nm,
said plural kinds of phosphors have different median values of particle sizes from each other,
the different median diameters are adjusted so that the plural kinds of phosphors have different settling speeds, and
a concentration of the phosphor that emits the secondary light having the peak wavelength in the range from 600 nm to 650 nm adjacent the light-emitting element is higher than a concentration of the phosphor that emits the secondary light having the peak wavelength in the range from 500 nm to 550 nm adjacent the light-emitting element.

2. The light-emitting device of claim 1 , wherein
said binder resin is silicone-based resin.

3. The light-emitting device of claim 1 , wherein
said binder resin is epoxy-based resin.

4. A liquid crystal display having said light-emitting device of claim 1 as a backlight light source.

Assignees

• Sharp Kk

Inventors

• Masuda Masatsugu
• Katoh Masaaki
• Inoguchi Tsukasa

Classifications

• H10W90/756

  between a chip and a stacked lead frame, conducting package substrate or heat sink · CPC title

• H10W90/736

  between a chip and a stacked lead frame, conducting package substrate or heat sink · CPC title

• H10W72/5522

  comprising gold [Au] · CPC title

• H10W72/884

  Die-attach connectors and bond wires · CPC title

• C09K11/77214

  Aluminosilicates · CPC title