LIGHT EMITTING DEVICE AND METHOD OF MANUFACTURING SAME

• US 20180277721A1
• Filed: 03/23/2018
• Published: 09/27/2018
• Est. Priority Date: 03/24/2017
• Status: Active Grant

• Current Assignee: Nichia Corporation
• Original Assignee: Nichia Corporation
• Inventors: BANDO, Shusaku, SOGAI, Takanobu, SHICHIJO, Satoshi
• Granted Patent: US 10,873,008 B2
• Time in Patent Office: Days
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 2933/005 relating to encapsulations
• CPC Class Codes: H01L 33/382 the electrode extending partially in or entirely through the semiconductor body
• CPC Class Codes: H01L 33/387 with a plurality of electrode regions in direct contact with the semiconductor body and being electrically interconnected by another electrode layer
• CPC Class Codes: H01L 33/486 adapted for surface mounting
• CPC Class Codes: H01L 33/502 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 33/54 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

Abstract

A light emitting device including: a light emitting element, a phosphor plate, and a light guiding part. The lower face of the light emitting element has a rectangular shape. The light guiding part covers lateral faces of the light emitting element and the lower face of the phosphor plate that is exposed from the light emitting element. The light guiding part has one or more lateral faces having at least one of structures below: a height at both ends being different from the height at a central area; outer lateral faces being parallel to the lateral faces of the light emitting element.

Claims

1. A light emitting device comprising:

a light emitting element having an upper face, a lower face, lateral faces, and including a positive electrode and a negative electrode positioned on the lower face, the light emitting element emitting light from the upper face;

a phosphor plate configured with an inorganic material containing a phosphor, the phosphor plate having an upper face, lateral faces, and a lower face that is larger than the upper face of the light emitting element and is in direct contact with the upper face of the light emitting element; and

a light guiding part covering the lateral faces of the light emitting element and the lower face of the phosphor plate that is exposed from the light emitting element, wherein

the lower face of the light emitting element has a rectangular shape;

the light guiding part has a height hd defined in a cross section perpendicular to the lower face that includes one of the two diagonal lines of the rectangular shape at a position farthest from the light emitting element,

the light guiding part has a height dc in a cross section perpendicular to the lower face that includes a line passing through an intersection of the two diagonal lines of the rectangular shape and in parallel to one side of the rectangular shape at a position farthest from the light emitting element, and

the height hd is different from the height hc.

2. The light emitting device according to claim 1 further comprising

a light reflecting part that covers the lateral faces of the phosphor plate and the light guiding part.

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

the height hd and the height hc satisfy the relationship:

hd>

hc.

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

the height hd and the height hc satisfy the relationship:

hd<

hc.

5. The light emitting device according to claim 1, wherein the light emitting element is flip chip mounted on a mounting board.

6. The light emitting device according to claim 1, wherein the thickness of the phosphor plate is 50 μ

m to 300 μ

m.

7. The light emitting device according to claim 1, wherein an arithmetic average roughness of the lower face of the phosphor plate is 1 nm at most.

8. A light emitting device comprising:

a light emitting element having an upper face, a lower face, lateral faces, and including a positive electrode and a negative electrode positioned on the lower face, the light emitting element emitting light from the upper face;

a phosphor plate formed with an inorganic material containing a phosphor and having an upper face, lateral faces, and a lower face which is larger than the upper face of the light emitting element and is in direct contact with the upper face of the light emitting element;

a light guiding part covering the lateral faces of the light emitting element and the lower face of the phosphor plate that is exposed from the light emitting element; and

a light reflecting part covering the lateral faces of the phosphor plate and the light guiding part, wherein

the light guiding part has outer lateral faces being parallel to the lateral faces of the light emitting element.

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

the outer lateral faces of the light guiding part are in contact with the lower face perimeter of the phosphor plate.

10. A method of manufacturing a light emitting device comprising:

arranging a plurality of light emitting elements each having an upper face, lower face, lateral faces, and including a positive electrode and a negative electrode positioned on the lower face, the light emitting element emitting light from the upper face arranged on a support so that the lower face opposes the support;

arranging a phosphor plate that has an upper face and a lower face so that the lower face of the phosphor plate faces the upper faces of the plurality of light emitting elements, and bonding the lower face of the phosphor plate and the upper faces of the plurality of light emitting elements by direct bonding;

subsequent to removing the support, arranging a light transmissive resin between the plurality of light emitting elements while orienting the phosphor plate so that the upper face of the phosphor plate is positioned at a bottom;

obtaining a plurality of intermediates each including a light emitting element, a phosphor plate positioned on the upper face of the light emitting element, and a light guiding part formed with the light transmissive resin at the lateral faces, the plurality of intermediates obtained by cutting the phosphor plate and the light transmissive resin between the plurality of light emitting elements;

providing a mounting board and bonding the intermediates on the mounting board; and

forming a light reflecting part that covers lateral faces of the light guiding parts, the lateral faces of the phosphor plates, and the lateral faces and the lower faces of the light emitting elements in the intermediates.

11. The method of manufacturing a light emitting device according to claim 10, wherein

the direct bonding in the step of arranging the phosphor plate is any of surface activated bonding, atomic diffusion bonding, and hydroxyl bonding.

12. The method of manufacturing a light emitting device according to claim 10, wherein

the lower face of each light emitting element has a rectangular shape having two side lengths a and b, and

in the step of arranging a plurality of light emitting elements, a first group of the light emitting elements are two dimensionally arranged on the support using a prescribed point as a reference point for the first group at pitch p in a first direction along the side length a, where p satisfies 2a<

p, and pitch q in a second direction along the side length b, where q satisfies 2b<

q, and

a second group of the light emitting elements are two dimensionally arranged on the support at pitch p in the first direction along the side length a and pitch q in the second direction along the side length b using a point which is p/2 and q/2 away from the reference point for the first group in the first direction and the second direction, respectively, as a reference point for the second group.

13. The method of manufacturing a light emitting device according to claim 10, wherein

the lower face of each light emitting element has a rectangular shape having two side lengths a and b, and

in the step of arranging a plurality of light emitting elements, the plurality of light emitting elements are two dimensionally arranged on the support at pitch r in the first direction along the side length a, where r satisfies a<

r<

2a, and pitch s in the second direction along the side length b, where s satisfies b<

s<

2b.

14. The method of manufacturing a light emitting device according to claim 10, wherein

the intermediates each include two or more light emitting elements, in the step of obtaining the plurality of intermediates.

15. The method of manufacturing a light emitting device according to claim 10, wherein

the intermediates each include only one light emitting element, in the step of obtaining the plurality of intermediates.

16. The method of manufacturing a light emitting device according to claim 10, wherein

an arithmetic average roughness of the lower face of the phosphor plate is 1 nm at most, in the step of arranging the phosphor plate.