Light emitting device

• US 10,355,175 B2
• Filed: 01/31/2017
• Issued: 07/16/2019
• Est. Priority Date: 03/10/2016
• Status: Active Grant

• Current Assignee: Panasonic Intellectual Property Management Co., Ltd. (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Intellectual Property Management Co., Ltd. (Panasonic Holdings Corporation)
• Inventors: Lee, Youshin, Oshio, Shozo, Okuno, Tatsuya, Abe, Takeshi, Nakamura, Masahiro
• Primary Examiner(s): Patel, Vip
• Application Number:
  US16/071,906
• Publication Number:
  US 20190027656A1
• Time in Patent Office: 896 Days
• Field of Search: None
• CPC Class Codes: C09K 11/08 containing inorganic luminescent materials
• CPC Class Codes: C09K 11/7774 Aluminates
• CPC Class Codes: F21S 2/00 Systems of lighting devices, not provided for in main groups F21S4/00 - F21S10/00 or F21S19/00, e.g. of modular construction
• CPC Class Codes: F21V 13/14 the elements being filters or photoluminescent elements, reflectors and refractors
• CPC Class Codes: F21V 9/32 characterised by the arrangement of the photoluminescent material
• CPC Class Codes: F21V 9/38 Combination of two or more photoluminescent elements of different materials
• CPC Class Codes: G02B 5/20 Filters polarising elements G02B5/30
• CPC Class Codes: H01L 33/16 with a particular crystal structure or orientation, e.g. polycrystalline, amorphous or porous
• CPC Class Codes: H01L 33/50 Wavelength conversion elements
• CPC Class Codes: H01L 33/502 Wavelength conversion materials
• CPC Class Codes: H01L 33/58 Optical field-shaping elements
• CPC Class Codes: H01S 5/0087 for illuminating phosphorescent or fluorescent materials, e.g. using optical arrangements specifically adapted for guiding or shaping laser beams illuminating these materials
• CPC Class Codes: H01S 5/02212 Can-type, e.g. TO-CAN housings with emission along or parallel to symmetry axis
• CPC Class Codes: H01S 5/32341 blue laser based on GaN or GaP
• CPC Class Codes: Y02B 20/00 Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps

Abstract

A light emitting device 1 includes: a substrate 30; and a phosphor layer 40 composed in such a manner that a large number of phosphor particles 60 are adhered onto a flat surface 32 of the substrate 30. At least one of the phosphor particles 60 is a polyhedral phosphor particle 65 that is monodispersed, is derived from a crystal structure of garnet and has facets, and a median particle size D₅₀ of the polyhedral phosphor particle 65 is 30 μm or more and a maximum thickness of the phosphor layer 40 or less. It is preferable that at least one of the phosphor particles 60 adhered onto the flat surface 32 of the substrate 30 is the polyhedral phosphor particle 65 that is monodispersed, is derived from the crystal structure of the garnet, and has the facets.

Claims

1. A light emitting device comprising:

a substrate; and

a phosphor layer composed in such a manner that a large number of phosphor particles are adhered onto a flat surface of the substrate,

wherein at least one of the phosphor particles is a polyhedral phosphor particle that is monodispersed, is derived from a crystal structure of garnet and has facets, and

a median particle size D₅₀ of the polyhedral phosphor particle is 30 μ

m or more and a maximum thickness of the phosphor layer or less.

2. The light emitting device according to claim 1, at least one of the phosphor particles adhered onto the flat surface of the substrate is the polyhedral phosphor particle that is monodispersed, is derived from the crystal structure of the garnet, and has the facets.

3. The light emitting device according to claim 1, wherein, in at least one of the polyhedral phosphor particles adhered onto the flat surface of the substrate, an area of at least one of the facets exceeds 200 μ

m².

4. The light emitting device according to claim 1, wherein the facets of the polyhedral phosphor particles and the flat surface of the substrate are adhered to each other in a surface contact manner.

5. The light emitting device according to claim 4, wherein a plurality of portions where the facets of the polyhedral phosphor particles and the flat surface of the substrate are adhered to each other in a surface contact manner are provided.

6. The light emitting device according to claim 1, wherein the facets of the adjacent polyhedral phosphor particles are adhered to one another in a surface contact manner.

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

substrate-phosphor adhesion portions which adhere the flat surface of the substrate and the facets of the polyhedral phosphor particles in the phosphor layer to each other,

wherein the substrate-phosphor adhesion portions are made of an inorganic binding agent.

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

inter-phosphor particle adhesion portions which adhere the facets of the adjacent polyhedral phosphor particles to one another,

wherein the inter-phosphor particle adhesion portions are made of an inorganic binding agent.

9. The light emitting device according to claim 7, wherein the inorganic binding agent is nanoparticles made of at least one inorganic oxide selected from the group consisting of Al₂O₃, ZnO, MoO₃ and ZnMoO₄.

10. The light emitting device according to claim 7, wherein the inorganic binding agent is nanoparticles with a median particle size D₅₀ of 1 nm or more and 100 nm or less.

11. The light emitting device according to claim 1, wherein the phosphor particles are excited by a laser beam.