Light emitting device having wavelength conversion layer with filling particles

• US 10,230,025 B2
• Filed: 11/21/2017
• Issued: 03/12/2019
• Est. Priority Date: 12/10/2015
• Status: Active Grant

• Current Assignee: Nichia Corporation
• Original Assignee: Nichia Corporation
• Inventors: Iwata, Hiroshi, Hosokawa, Shoji
• Primary Examiner(s): Jahan, Bilkis
• Application Number:
  US15/818,740
• Publication Number:
  US 20180097153A1
• Time in Patent Office: 476 Days
• Field of Search: None
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2933/0041 relating to wavelength conversion elements
• CPC Class Codes: H01L 2933/005 relating to encapsulations
• CPC Class Codes: H01L 2933/0058 relating to optical field-shaping elements
• CPC Class Codes: H01L 2933/0066 relating to arrangements for conducting electric current to or from the semiconductor body
• CPC Class Codes: H01L 33/504 Elements with two or more wavelength conversion materials
• CPC Class Codes: H01L 33/54 having a particular shape
• CPC Class Codes: H01L 33/56 Materials, e.g. epoxy or silicone resin
• CPC Class Codes: H01L 33/60 Reflective elements
• CPC Class Codes: H01L 33/62 Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls

Abstract

A light emitting device includes a light emitting element and a wavelength conversion layer covering the light emitting element. The wavelength conversion layer includes first wavelength conversion particles, second wavelength conversion particles, and filling particles. The first wavelength conversion particles contains aluminum. The second wavelength conversion particles have outer surfaces covered with covering material which contains aluminum. The filling particles contain aluminum. The filling particles are provided among the first wavelength conversion particles and the second wavelength conversion particles. The filling particles have particle sizes smaller than particle sizes of the first wavelength conversion particles and particle sizes of the second wavelength conversion particles. The filling particles have aspect ratios smaller than aspect ratios of the first wavelength conversion particles and aspect ratios of the second wavelength conversion particles.

Claims

1. A light emitting device comprising:

a light emitting element; and

a wavelength conversion layer covering the light emitting element and comprising;

first wavelength conversion particles containing aluminum;

second wavelength conversion particles having outer surfaces covered with covering material containing aluminum; and

filling particles containing aluminum and provided among the first wavelength conversion particles and the second wavelength conversion particles, the filling particles having particle sizes smaller than particle sizes of the first wavelength conversion particles and particle sizes of the second wavelength conversion particles and having aspect ratios smaller than aspect ratios of the first wavelength conversion particles and aspect ratios of the second wavelength conversion particles.

2. The light emitting device according to claim 1,

wherein a surface of the light emitting element is covered with a second covering layer containing aluminum.

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

a light-transmissive resin covering the wavelength conversion layer.

4. The light emitting device according to claim 1, comprising:

a base on which the light emitting element, the base including a conducting member to be bonded to the light emitting element.

5. The light emitting device according to claim 4, comprising:

a reflecting layer covering the wavelength conversion layer provided on the conductive member.

6. The light emitting device according to claim 1, wherein the particle size of the second wavelength conversion particles is larger than the particle size of the first wavelength conversion particles.

7. The light emitting device according to claim 1, wherein the aspect ratio of the second wavelength conversion particles is larger than the aspect ratio of the first wavelength conversion particles.

8. The light emitting device according to claim 1, wherein the particle size of the first wavelength conversion particles is in a range of 3.0 μ

m to 9.5 μ

m.

9. The light emitting device according to claim 1, wherein the particle size of the second wavelength conversion particles is in a range of 5.5 μ

m to 12.0 μ

m.

10. The light emitting device according to claim 1, wherein the particle size of the filling particles is in a range of 0.3 μ

m to 9.0 μ

m.

11. The light emitting device according to claim 1, wherein the aspect ratio of the filling particles is in a range of 1.0 to 1.3.

12. The light emitting device according to claim 1, wherein the first wavelength conversion particles are made of YAG.

13. The light emitting device according to claim 1, wherein a base material of the second wavelength conversion is SCASN.

14. The light emitting device according to claim 1, wherein the filling particles are made of aluminum oxide.

15. The light emitting device according to claim 1, wherein the covering material is aluminum oxide.

16. The light emitting device according to claim 1, wherein the wavelength conversion layer has substantially uniform thickness.