Light emitting device

• US 11,043,620 B2
• Filed: 12/31/2019
• Issued: 06/22/2021
• Est. Priority Date: 12/26/2016
• Status: Active Grant

• Current Assignee: Nichia Corporation
• Original Assignee: Nichia Corporation
• Inventors: Yamamoto, Atsushi, Ono, Keiko
• Primary Examiner(s): Sabur, Alia
• Application Number:
  US16/731,310
• Publication Number:
  US 20200135993A1
• Time in Patent Office: 539 Days
• CPC Class Codes: F21V 7/0083 Array of reflectors for a cluster of light sources, e.g. arrangement of multiple light sources in one plane combination of two or more reflectors F21V7/0025
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/133605 including specially adapted reflectors
• CPC Class Codes: G02F 1/133606 including a specially adapted diffusing, scattering or light controlling members
• CPC Class Codes: G02F 1/133611 including means for improving the brightness uniformity
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 2933/0091 Scattering means in or on the semiconductor body or semiconductor body package H01L33/22 takes precedence
• CPC Class Codes: H01L 33/46 Reflective coating, e.g. dielectric Bragg reflector
• CPC Class Codes: H01L 33/504 Elements with two or more wavelength conversion materials
• CPC Class Codes: H01L 33/505 characterised by the shape, e.g. plate or foil
• CPC Class Codes: H01L 33/507 the elements being in intimate contact with parts other than the semiconductor body or integrated with parts other than the semiconductor body
• CPC Class Codes: H01L 33/58 Optical field-shaping elements
• 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 mounting board, light sources, a light diffuser, a wavelength conversion layer, and scatter reflection portions. Each of the light sources has an upper face on which a light reflecting layer is disposed. The light diffuser is arranged above the plurality of light sources. The wavelength conversion layer is located at least between the light sources and the light diffuser. The wavelength conversion layer is configured to absorb at least a portion of light from the light sources and to emit light having a wavelength which is different from a wavelength of the light from the light sources. The scatter reflection portions are arranged on a surface of the wavelength conversion layer that is closer to the light diffuser. Each of the scatter reflection portions is arranged above at least a portion of the upper face of a corresponding one of the light sources.

Claims

1. A light emitting device comprising:

a mounting board;

a plurality of light sources arranged on the mounting board;

a light diffuser arranged above the plurality of light sources;

a plurality of scatter reflection portions each being arranged above at least a portion of an upper face of a corresponding one of the light sources, each of the scatter reflection portions containing particles of reflective material, and each of the scatter reflection portions having a single-layered or multi-layered structure in a cross-sectional view;

a partitioning member that is light-reflective, the partitioning member including walls defining each of a plurality of regions and surrounding each of the light sources on the mounting board, with each of the walls having an apex in a cross section; and

a wavelength conversion member located at least between the light sources and the light diffuser, the wavelength conversion member being configured to absorb at least a portion of light from the light sources and to emit light having a wavelength which is different from a wavelength of the light from the light sources,

wherein the apex of each of the walls is in contact with a lower face of the wavelength conversion member,

the walls of the partitioning member defining each of the plurality of regions include a first wall and a second wall, the first wall and the second wall extending along a first direction, and the first wall and the second wall opposing each other along a second direction which is different from the first direction,

each of the plurality of light sources include a first light source located between the first wall and the second wall defining the corresponding one of the plurality of regions, the first light source having a first width along the second direction, and

in a cross section of each of the plurality of regions along the second direction, the scatter reflection portion that is arranged above the first light source has a second width which is greater than the first width, the second width being smaller than a distance between the apex of the first wall and the apex of the second wall.

2. The light emitting device of claim 1, wherein

the wavelength conversion member covers lateral faces of each of the light sources.

3. The light emitting device of claim 1, further comprising

a protection layer covering at least lateral faces of each of the light sources.

4. The light emitting device of claim 1, further comprising

a conductor wiring layer which includes a plurality of interconnection patterns each connected to one or more of the light sources.

5. The light emitting device of claim 1, wherein

an array pitch between adjacent ones of the light sources is not less than 0.1 mm but less than 5 mm.

6. The light emitting device of claim 1, wherein

a distance from a surface of the mounting board, on which the light sources are arranged, to each of the scatter reflection portions is 1.5 mm or less.

7. The light emitting device of claim 1, wherein

a ratio of a distance from a surface of the mounting board, on which the light sources are arranged, to each of the scatter reflection portions with respect to an array pitch between adjacent ones of the light sources is not less than 0.1 and not more than 0.5.

8. The light emitting device of claim 1, wherein

each of the light sources has the upper face on which a light reflecting layer is disposed.

9. The light emitting device of claim 1, wherein

the plurality of scatter reflection portions are arranged on a surface of the wavelength conversion member that is closer to the light diffuser.

10. The light emitting device of claim 9, wherein

each of the scatter reflection portions includes

a first region arranged immediately above the corresponding one of the light sources, and

a second region surrounding the first region in a plan view,

with a density of the particles of the reflective material in the second region being smaller than a density of the particles of the reflective material in the first region.

11. The light emitting device of claim 10, wherein

each of the plurality of scatter reflection portions includes a first layer arranged on the surface of the wavelength conversion member continuously in the first region and in the second region in the plan view, and a second layer arranged on the first layer in the first region in the plan view.

12. The light emitting device of claim 10, wherein

a size of the first region is equal to or larger than a size of the light source in the plan view.

13. The light emitting device of claim 9, further comprising

a light-transmitting layer arranged between the wavelength conversion member and the light diffuser and covering the plurality of scatter reflection portions, the light-transmitting layer having a flat upper surface.

14. The light emitting device of claim 1, wherein

the wavelength conversion member is spaced apart from the mounting board.

15. The light emitting device of claim 1, wherein

a shape of each of the plurality of scatter reflection portions is a circle which is centered around an optical axis of the corresponding one of the light sources.

16. The light emitting device of claim 1, wherein

each of the light sources includes a light-emitting element including a nitride semiconductor.

17. The light emitting device of claim 1, wherein

the mounting board includes a metal layer arranged on a lower face opposite to an upper face on which the plurality of light sources are arranged.

18. The light emitting device of claim 1, further comprising

a protection layer covering at least lateral faces of each of the light sources.

19. The light emitting device of claim 18, wherein

the wavelength conversion member is arranged on or above the protection layer.

20. The light emitting device of claim 1, wherein

the partitioning member further includes planar bottoms each extending, in parallel with a surface of the mounting board, from bottom parts of the walls toward a corresponding one of the light sources.