Light emitting device and its method of manufacture

• US 9,202,999 B2
• Filed: 01/17/2014
• Issued: 12/01/2015
• Est. Priority Date: 01/18/2013
• Status: Active Grant

• Current Assignee: Nichia Corporation
• Original Assignee: Nichia Corporation
• Inventors: Okada, Satoshi, Kawano, Yusuke
• Primary Examiner(s): Kim, Su C
• Application Number:
  US14/158,260
• Publication Number:
  US 20140203305A1
• Time in Patent Office: 683 Days
• US Class Current: 1/1
• 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 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 2933/005 relating to encapsulations
• CPC Class Codes: H01L 33/486 adapted for surface mounting
• CPC Class Codes: H01L 33/50 Wavelength conversion elements
• CPC Class Codes: H01L 33/56 Materials, e.g. epoxy or silicone resin
• CPC Class Codes: H01L 33/58 Optical field-shaping elements

Abstract

The light emitting device is provided with a substrate, semiconductor light emitting elements mounted on the substrate, a mold frame that surrounds the periphery of the light emitting elements on the substrate, and resin layers that fill the inside of the mold frame. The mold frame includes a first mold frame, and a second mold frame formed on top of the first mold frame. The resin layers include a first resin layer that embeds the light emitting elements in resin and is formed with a height approximately equal to the height of the top of the first mold frame, and a second resin layer on top of the first resin layer that is formed with a height approximately equal to the height of the top of the second mold frame. At least one of the resin layers (which are the first resin layer and the second resin layer) includes wavelength-shifting material to change the wavelength of light emitted from the semiconductor light emitting elements.

Claims

1. A light emitting device comprising:

a substrate;

semiconductor light emitting elements mounted on the substrate;

a mold frame that surrounds the periphery of the light emitting elements on the substrate; and

resin layers that fill the inside of the mold frame,

wherein the mold frame includes a first mold frame, and a second mold frame formed on top of the first mold frame,

wherein the resin layers comprises;

a first resin layer that embeds the light emitting elements in resin and is formed with a height approximately equal to the height of the to of the first mold frame; and

a second resin layer formed on top of the first resin layer with a height approximately equal to the height of the top of the second mold frame,

wherein wavelength-shifting material to change the wavelength of light emitted from the semiconductor light emitting elements is included in at least one of the resin layers, which are the first resin layer and the second resin layer, and

wherein part of the second mold frame covers a portion of an upper surface of the edge of the first resin layer.

2. The light emitting device as cited in claim 1 wherein the substrate has an insulating planar surface, conducting material is formed on top of the insulating planar surface, and the semiconductor light emitting elements are electrically connected to the conducting material.

3. The light emitting device as cited in claim 1 wherein the first resin layer includes wavelength-shifting material to change the wavelength of light emitted from the semiconductor light emitting elements.

4. The light emitting device as cited in claim 1 wherein the second resin layer includes light diffusing material to diffuse light emitted from the semiconductor light emitting elements.

5. The light emitting device as cited in claim 1 wherein boundaries between the bottom edges of the inside surfaces of the first mold frame and the substrate are positioned further inside the mold frame than the bottom edges of the inside surfaces of the second mold frame.

6. The light emitting device as cited in claim 1 wherein part of the second mold frame covers the top of the first mold frame.

7. The light emitting device as cited in claim 1 wherein the position of the bottom edge of the inside surface of the second mold frame is further inside the mold frame than the position of interface between the first resin layer and the top of the first mold frame.

8. The light emitting device as cited in claim 1 wherein the second mold frame covers upper and outer surfaces of the first mold frame.

9. The light emitting device as cited in claim 1 wherein the walls of the second mold frame are made wider as viewed from above than the walls of the first mold frame.

11. The light emitting device as cited in claim 1 wherein the center region of the second resin layer is formed with approximately the same height as the top of the second mold frame.

12. The light emitting device as cited in claim 1 wherein the center region of the second resin layer is formed with a height exceeding the top of the second mold frame.

13. The light emitting device as cited in claim 1

wherein the wavelength-shifting material is fluorescent material that is excited by light emitted by the semiconductor light emitting elements, and

wherein the first resin layer includes a fluorescent material layer and a light-transmitting resin layer formed on top of the fluorescent material layer.

17. The light emitting device as cited in claim 1 wherein the first mold frame is formed in a dome-shape.

18. The light emitting device as cited in claim 1 wherein the second mold frame is formed in a dome-shape.

10. A light emitting device comprising:

a substrate;

semiconductor light emitting elements mounted on the substrate;

a mold frame that surrounds the periphery of the light emitting elements on the substrate; and

resin layers that fill the inside of the mold frame,

wherein the mold frame includes a first mold frame, and a second mold frame formed on top of the first mold frame,

wherein the resin layers comprises;

a first resin layer that embeds the light emitting elements in resin and is formed with a height approximately equal to the height of the top of the first mold frame; and

a second resin layer formed on top of the first resin layer with a height approximately equal to the height of the top of the second mold frame,

wherein wavelength-shifting material to change the wavelength of light emitted from the semiconductor light emitting elements is included in at least one of the resin layers, which are the first resin layer and the second resin layer,

wherein the walls of the second mold frame are made wider as viewed from above than the walls of the first mold frame, and

wherein a protection device is connected with reverse polarity in parallel with the semiconductor light emitting elements, and the protection device is embedded inside the second mold frame.

14. A method of manufacturing a light emitting device, the light emitting device comprising:

a substrate;

semiconductor light emitting elements mounted on the substrate;

a mold frame that surrounds the periphery of the light emitting elements mounted on the substrate; and

resin layers that fill the encapsulating region established inside the mold frame,

the method comprising;

forming a first mold frame on top of the substrate;

filling the encapsulating region inside the first mold frame with a first resin to a height approximately equal to the top of the first mold frame in a manner that encapsulates the light emitting elements mounted in the encapsulating region;

forming a second mold frame covering at least part of the first mold frame after solidifying the first resin to form a first resin layer such that part of the second mold frame covers a portion of an upper surface of the edge of the first resin layer;

filling the inside the second mold frame with a second resin to a height approximately equal to the top of the second mold frame; and

solidifying the second resin to form a second resin layer.

16. The method of manufacturing a light emitting device as cited in claim 14 wherein the viscosity of the resin used to form the first mold frame is higher than the viscosity of the resin used to form the second mold frame.

15. A method of manufacturing a light emitting device, the method comprising:

preparing a substrate with conducting material disposed on top of an insulating planar surface;

mounting semiconductor light emitting elements on the substrate in a manner making electrical connection with the conducting material, and to form a first mold frame around the periphery of the light emitting elements;

forming a first resin layer in the region established inside the first mold frame;

forming a second mold frame over the upper surface of the first mold frame such that part of the second mold frame covers a portion of an upper surface of the edge of the first resin layer; and

forming a second resin layer in the region established by the second mold frame.