LIGHT EMITTING DEVICE AND MANUFACTURING METHOD THEREOF

• US 20180123001A1
• Filed: 10/19/2017
• Published: 05/03/2018
• Est. Priority Date: 05/14/2014
• Status: Active Grant

• Current Assignee: Nichia Corporation
• Original Assignee: Genesis Photonics Inc.
• Inventors: Hung, Cheng-Wei, Tu, Long-Chi, Chang, Jui-Fu, Tseng, Chun-Ming, Chen, Yun-Chu
• Granted Patent: US 10,439,111 B2
• Time in Patent Office: Days
• CPC Class Codes: H01L 2224/18 High density interconnect [HDI] connectors; Manufacturing methods related thereto
• 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 2933/0091 Scattering means in or on the semiconductor body or semiconductor body package H01L33/22 takes precedence
• CPC Class Codes: H01L 33/486 adapted for surface mounting
• CPC Class Codes: H01L 33/505 characterised by the shape, e.g. plate or foil
• CPC Class Codes: H01L 33/508 having a non-uniform spatial arrangement or non-uniform concentration, e.g. patterned wavelength conversion layer, wavelength conversion layer with a concentration gradient of the wavelength conversion material
• 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 including at least one light-emitting unit, a wavelength conversion adhesive layer, and a reflective protecting element is provided. The light-emitting unit has an upper surface and a lower surface opposite to each other. The light-emitting unit includes two electrode pads, and the two electrode pads are located on the lower surface. The wavelength conversion adhesive layer is disposed on the upper surface. The wavelength conversion adhesive layer includes a low-concentration fluorescent layer and a high-concentration fluorescent layer. The high-concentration fluorescent layer is located between the low-concentration fluorescent layer and the light-emitting unit. The width of the high-concentration fluorescent layer is W_H. The width of the low-concentration fluorescent layer is W_L. The width of the light-emitting unit is W_E. The light-emitting device further satisfies the following inequalities: W_E<W_L, W_H<W_L and 0.8<W_H/W_E≤1.2. Furthermore, a manufacturing method of the light-emitting device is also provided.

Claims

1. A light-emitting device, comprising:

at least one light-emitting unit, wherein the light-emitting unit has an upper surface and a lower surface opposite to each other, the light-emitting unit comprises two electrode pads, and the two electrode pads are located on the lower surface of the light-emitting unit;

a wavelength conversion adhesive layer, disposed on the upper surface of the light-emitting unit, wherein the wavelength conversion adhesive layer comprises a low-concentration fluorescent adhesive layer and a high-concentration fluorescent adhesive layer, and the high-concentration fluorescent adhesive layer is located between the low-concentration fluorescent adhesive layer and the light-emitting unit; and

a reflective protecting element, covering the light-emitting unit and a portion of the wavelength conversion adhesive layer and at least exposing the two electrode pads of the light-emitting unit and the low-concentration fluorescent layer,

wherein a width of the high-concentration fluorescent adhesive layer is W_H, a width of the low-concentration fluorescent adhesive layer is W_L, a width of the light-emitting unit is W_E, and the light-emitting device further satisfies the following inequalities;

W_E<

W_L, W_H<

W_L; and

0.8<

W_H/W_E≤

1.2.

2. The light-emitting device of claim 1, wherein the wavelength conversion adhesive layer further comprises a first mesa portion and a plurality of second mesa portions, the first mesa portion comprises the high-concentration fluorescent adhesive layer and a first portion of the low-concentration fluorescent adhesive layer, each of the second mesa portions comprises a second portion of the low-concentration fluorescent adhesive layer, and the first portion of the low-concentration fluorescent adhesive layer is connected to the second portion of the low-concentration fluorescent adhesive layer.

3. The light-emitting device of claim 1, wherein the reflective protecting element has a concave surface, and the concave surface is recessed toward the wavelength conversion adhesive layer.

4. The light-emitting device of claim 1, further comprising a translucent adhesive layer, wherein the light-emitting unit further comprises a side surface connected to the upper surface and the lower surface, and the translucent adhesive layer is disposed on the low-concentration fluorescent adhesive layer and extended to the side surface of the light-emitting unit.

5. The light-emitting device of claim 1, wherein the reflective protecting element covers the wavelength conversion adhesive layer and exposes a portion of a side of the wavelength conversion adhesive layer.

6. The light-emitting device of claim 1, wherein the reflective protecting element has a reflective surface, and the reflective surface is in contact with the light-emitting unit.

7. The light-emitting device of claim 6, wherein a first side of the reflective surface is in contact with the light-emitting unit, and a second side of the reflective surface is extended toward the wavelength conversion adhesive layer and away from the light-emitting unit.

8. The light-emitting device of claim 6, wherein the reflective surface is a curved surface.

9. A manufacturing method of a light-emitting device, comprising:

forming a wavelength conversion adhesive layer, wherein the wavelength conversion adhesive layer comprises a low-concentration fluorescent layer and a high-concentration fluorescent layer;

providing a plurality of light-emitting units;

forming a plurality of trenches in the wavelength conversion adhesive layer to define a plurality of bonding regions between the trenches, wherein in the bonding regions, a width of the high-concentration fluorescent adhesive layer is W_H, a width of the low-concentration fluorescent adhesive layer is W_L, a width of the light-emitting unit is W_E, and the step further satisfies the following inequalities;

W_E<

W_L, W_H<

W_L, and 0.8<

W_H/W_E≤

1.2;

respectively bonding the light-emitting units to the high-concentration fluorescent adhesive layers in the bonding regions;

forming a reflective protecting element on the wavelength conversion adhesive layer and between the light-emitting units to completely fill the trenches, wherein the reflective protecting element exposes the electrode pads of the light-emitting units; and

performing a cutting process along the trenches to form a plurality of light-emitting devices.

10. The manufacturing method of the light-emitting device of claim 9, wherein in the step of forming the trenches in the wavelength conversion adhesive layer further comprises:

removing a portion of the high-concentration fluorescent adhesive layer and a portion of the low-concentration fluorescent adhesive layer to form a plurality of first sub-trenches, wherein the first sub-trenches respectively form a plurality of first mesa portions in the bonding regions, and each of the first mesa portions further comprises a first portion of the high-concentration fluorescent adhesive layer and a first portion of the low-concentration fluorescent adhesive layer; and

removing a portion of the low-concentration fluorescent adhesive layer to form a plurality of second sub-trenches in the first sub-trenches, wherein the second sub-trenches respectively form a plurality of second mesa portions in the bonding regions, each of the second mesa portions further comprises a second portion of the low-concentration fluorescent adhesive layer, and the first portion of the low-concentration fluorescent adhesive layer and the second portion of the low-concentration fluorescent adhesive layer are connected to each other,

wherein the trench comprises the first sub-trench and the second sub-trench.

11. The manufacturing method of the light-emitting device of claim 9, further comprising, before the step of respectively bonding the light-emitting units to the high-concentration fluorescent adhesive layers in the bonding regions:

respectively forming a plurality of translucent adhesive layers on the high-concentration fluorescent adhesive layers in the bonding regions.

12. The manufacturing method of the light-emitting device of claim 11, wherein in the step of respectively bonding the light-emitting units to the high-concentration fluorescent adhesive layers in the bonding regions, the light-emitting units are respectively bonded to the high-concentration fluorescent adhesive layers via the translucent adhesive layers.

13. The manufacturing method of the light-emitting device of claim 9, further comprising, after the step of forming the reflective protecting element on the wavelength conversion adhesive layer and between the light-emitting units to completely fill the trenches:

leaving the reflective protecting element to stand such that the reflective protecting element forms a concave surface recessed toward the wavelength conversion adhesive layer; and

curing the reflective protecting element.