Light emitting device, surface light source, liquid crystal display device, and method for manufacturing light emitting device

• US 9,634,203 B2
• Filed: 05/29/2009
• Issued: 04/25/2017
• Est. Priority Date: 05/30/2008
• Status: Active Grant

• Current Assignee: Shenzhen Jufei Optoelectronics Co., Ltd.
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Ito, Shin, Okada, Yutaka, Matsuo, Takanobu, Ohta, Masayuki
• Primary Examiner(s): Coughlin, Andrew
• Assistant Examiner(s): APENTENG, JESSICA MCMILLAN
• Application Number:
  US12/995,364
• Publication Number:
  US 20110085352A1
• Time in Patent Office: 2,888 Days
• Field of Search: 362561, 362 84, 362 971- 974, 362600-634
• CPC Class Codes: G02B 6/0023 provided by one optical element, or plurality thereof, placed between the light guide and the light source, or around the light source
• CPC Class Codes: G02B 6/0055 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0068 Arrangements of plural sources, e.g. multi-colour light sources
• CPC Class Codes: G02B 6/0073 Light emitting diode [LED]
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/133609 including means for improving the color mixing, e.g. white
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48137 the bodies being arranged next to each other, e.g. on a common substrate
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 33/44 characterised by the coatings, e.g. passivation layer or anti-reflective coating
• CPC Class Codes: H01L 33/50 Wavelength conversion elements
• CPC Class Codes: H01L 33/505 characterised by the shape, e.g. plate or foil
• CPC Class Codes: H01L 33/54 having a particular shape
• CPC Class Codes: H01L 33/58 Optical field-shaping elements

Abstract

A light emitting device includes: a substrate having a main surface; a phosphor layer provided on the main surface and containing an LED element that emits primary light and a fluorescent particle that absorbs a part of the primary light and emits secondary light; and a transparent resin layer having a refractive index n and covering the phosphor layer. The transparent resin layer has an outer circumferential surface that forms a boundary between the transparent resin layer and the atmosphere. When a minimum circumference that includes the overall phosphor layer and is concentric with the outer circumferential surface has a radius r in a cut surface where at least a part of the outer circumferential surface takes a shape of an arc having a radius R, a relationship of R>r·n is satisfied. With such configuration, the light extraction efficiency is enhanced.

Claims

1. A light emitting device, comprising:

a substrate having a main surface;

an inner portion provided on said main surface and containing a semiconductor light emitting element that emits primary light and a fluorescent particle that absorbs a part of the primary light and emits secondary light;

an outer portion having a refractive index n and covering said inner portion, wherein

said outer portion has an outer circumferential surface exposed to the atmosphere,

when a minimum spherical circumference that includes overall said inner portion and is concentric with said outer circumferential spherical surface has a radius r in a cut surface where at least a part of said outer circumferential spherical surface takes a shape of an arc having a radius R, a relationship of R>

r·

n is satisfied;

wherein said outer portion is formed of a single transparent layer;

said inner portion is a phosphor layer containing said fluorescent particle, and said phosphor layer is provided to be in direct contact with said semiconductor light emitting element and directly cover said semiconductor light emitting element; and

wherein said fluorescent particle is provided only in said inner portion, of said inner portion and said outer portion.

2. The light emitting device according to claim 1, wherein

said inner portion contains a plurality of said semiconductor light emitting elements.

3. The light emitting device according to claim 1, further comprising

a scattered particle dispersed in said inner portion, for scattering the primary light and the secondary light.

4. The light emitting device according to claim 1, wherein

said outer portion and said inner portion are formed in a shape of concentric hemispheres having radius R and radius r (r<

R/n), respectively.

5. The light emitting device according to claim 1, wherein

said outer portion and said inner portion are formed in a shape of concentric semicircles having radius R and radius r (r<

R/n) in said cut surface, respectively, and

the outer circumferential surface of said outer portion has a shape of a semicircular column.

6. The light emitting device according to claim 1, wherein

a center of said outer circumferential surface and said circumference is arranged on said main surface or within said substrate.

7. The light emitting device according to claim 1, wherein

said inner portion has any one of a rectangular parallelepiped shape, a columnar shape and a polygonal columnar shape.

8. The light emitting device according to claim 1, wherein

when said inner portion has a refractive index n′

, a relationship of n<

n′

is satisfied.

9. The light emitting device according to claim 1, wherein

said inner portion is formed of a transparent resin or glass.

10. The light emitting device according to claim 1, wherein

said outer portion is formed of a transparent resin or glass.

11. The light emitting device according to claim 1, further comprising

a blocking component provided at a boundary portion between said inner portion and said outer portion on said main surface.

12. A surface light source, comprising:

a line light source having a plurality of light emitting devices according to claim 1 arranged in a straight line; and

a light guide plate having an emission surface that extends in a planar shape and an incidence end surface that extends in a thickness direction of the light guide plate from a periphery of said emission surface and on which light emitted from said line light source is incident, and

upon reception of the light incident on said incidence end surface, light being emitted from said emission surface.

13. A liquid crystal display device, comprising:

the surface light source according to claim 12; and

a liquid crystal display panel arranged to face said surface light source and irradiated from a rear surface by said surface light source.

14. A surface light source, comprising a plurality of light emitting devices according to claim 1 arranged in a planar shape.

15. A liquid crystal display device, comprising:

the surface light source according to claim 14; and

a liquid crystal display panel arranged to face said surface light source and irradiated from a rear surface by said surface light source.