Light emitting device comprising micro-structures

• US 10,050,173 B2
• Filed: 02/17/2016
• Issued: 08/14/2018
• Est. Priority Date: 02/17/2015
• Status: Active Grant

• Current Assignee: Nichia Corporation
• Original Assignee: Genesis Photonics Inc.
• Inventors: Huang, Jing-En, Kang, Kai-Shun, Kuo, Yu-Chen, Lu, Fei-Lung, Lai, Teng-Hsien
• Primary Examiner(s): Monbleau, Davienne
• Assistant Examiner(s): Cruz, Leslie Pilar
• Application Number:
  US15/045,273
• Publication Number:
  US 20160247985A1
• Time in Patent Office: 909 Days
• CPC Class Codes: B28D 5/0011 with preliminary treatment, e.g. weakening by scoring
• CPC Class Codes: H01L 33/0095 Post-treatment of devices, e.g. annealing, recrystallisation or short-circuit elimination
• CPC Class Codes: H01L 33/20 with a particular shape, e.g. curved or truncated substrate
• CPC Class Codes: H01L 33/22 Roughened surfaces, e.g. at the interface between epitaxial layers

Abstract

A light emitting device includes a semiconductor light emitting unit and a light-transmitting substrate. The light-transmitting substrate includes an upper surface having two long sides and two short sides and a side surface, and the semiconductor light emitting unit is disposed on the upper surface. The side surface includes two first surfaces, two second surfaces, and rough micro-structures. Each of the first surfaces is connected to one of the long sides of the upper surface, and each of the second surfaces is connected to one of the short sides of the upper surface. The rough micro-structures are formed on the first surfaces and the second surfaces, a covering rate of the rough micro-structures on each of the first surfaces is greater than or equal to a covering rate of the rough micro-structures on each of the second surfaces. A manufacturing method of the light emitting device is also provided.

Claims

1. A light emitting device, comprising:

a semiconductor light emitting unit; and

a light-transmitting substrate, comprising;

an upper surface having two long sides and two short sides, the semiconductor light emitting unit is disposed on the upper surface; and

a side surface comprising two first surfaces, two second surfaces, and rough micro-structures, each of the first surfaces is connected to one of the two long sides, each of the second surfaces is connected to one of the two short sides, the rough micro-structures are formed on the two first surfaces and the two second surfaces, wherein an area ratio of the rough micro-structures to each of the first surfaces is greater than an area ratio of the rough micro-structures to each of the second surfaces.

2. The light emitting device according to claim 1, wherein each of the first surfaces comprises at least a first strip-shaped region, each of the second surfaces comprises at least a second strip-shaped region, the first strip-shaped regions extends along a first direction, the second strip-shaped regions extends along a second direction, the first direction and the second direction are parallel to the upper surface, and the rough micro-structures are disposed on the first strip-shaped regions and the second strip-shaped regions.

3. The light emitting device according to claim 2, wherein the first strip-shaped region of each of the first surfaces has a first width at a direction perpendicular to the first direction, the second strip-shaped region of each of the second surfaces has a second width at a direction perpendicular to the second direction, the first width is greater than or equal to the second width.

4. The light emitting device according to claim 2, wherein each of the first surfaces comprises a plurality of the first strip-shaped regions, and a quantity of the first strip-shaped regions on each of the first surfaces is greater than a quantity of the second strip-shaped regions on each of the second surfaces.

5. The light emitting device according to claim 4, wherein the first strip-shaped regions on each of the first surfaces have at least an interval region therebetween, and an area ratio of the interval region on the first surface falls within a range of 0.4 to 0.8.

6. The light emitting device according to claim 2, wherein at least one of the first strip-shaped regions of each of the first surfaces is connected to one of the second strip-shaped regions of the second surface.

7. The light emitting device according to claim 1, wherein the light-transmitting substrate satisfies:

8. The light emitting device according to claim 1, wherein the light-transmitting substrate satisfies:

9. The light emitting device according to claim 1, wherein a ratio of a length of each of the long sides to a length of each of the short sides falls within a range of 1 to 20.

10. The light emitting device according to claim 1, wherein the light-transmitting substrate is formed by a crystalline material, the crystalline material comprises a first crystal plane and a second crystal plane, the long side is perpendicular to a normal vector of the first crystal plane, the upper surface is parallel to the second crystal plane, an included angle formed by the normal vector of the first crystal plane and a normal vector of the second crystal plane is greater than 90°

.

11. The light emitting device according to claim 10, wherein the crystalline material further comprises a third crystal plane, a normal vector of the third crystal plane is perpendicular to the normal vector of the second crystal plane.

12. The light emitting device according to claim 10, wherein the first crystal plane is a (1012) crystal plane, and the second crystal plane is a (0001) crystal plane.

13. The light emitting device according to claim 10, wherein the crystalline material is sapphire.

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

providing a wafer, the wafer comprises a flat edge;

cutting the wafer along a first direction by a cutting light beam, the first direction is substantially perpendicular or nearly perpendicular to the flat edge; and

cutting the wafer along a second direction by the cutting light beam, so as to form a plurality of light emitting devices, the second direction is substantially parallel or nearly parallel to the flat edge, wherein each of the light emitting devices comprises;

a semiconductor light emitting unit; and

a light-transmitting substrate, comprising;

an upper surface having two long sides and two short sides, the two long sides are parallel to the first direction, the two short sides are parallel to the second direction, the semiconductor light emitting unit is disposed on the upper surface; and

a side surface comprising two first surfaces, two second surfaces, and rough micro-structures, each of the first surfaces is connected to one of the two long sides, each of the second surfaces is connected to one of the two short sides, the rough micro-structures are formed on the two first surfaces and the two second surfaces through the cutting light beam, wherein an area ratio of the rough micro-structures to each of the first surfaces is greater than an area ratio of the rough micro-structures to each of the second surfaces.

15. The method for manufacturing the light emitting device according to claim 14, wherein in each of the light emitting devices, the cutting light beam forms at least a first strip-shaped region on each of the first surfaces, the cutting light beam forms at least a second strip-shaped region on each of the second surfaces.

16. The method for manufacturing the light emitting device according to claim 15, wherein the cutting light beam cuts the wafer along the first direction with a first width, the cutting light beam cuts the wafer along the second direction with a second width, and the first width is greater than or equal to the second width.

17. The method for manufacturing the light emitting device according to claim 15, wherein a number of time the cutting light beam cuts the wafer in the first direction is higher than a number of time the cutting light beam cuts the wafer in the second direction.

18. The method for manufacturing the light emitting device according to claim 17, wherein the first strip-shaped regions on each of the first surfaces have at least an interval region therebetween, and an area ratio of the interval region to the first surface falls within a range of 0.4 to 0.8.

19. The method for manufacturing the light emitting device according to claim 15, wherein at least one of the first strip-shaped regions of each of the first surfaces is connected to one of the second strip-shaped regions of the second surface.

20. The method for manufacturing the light emitting device according to claim 14, wherein the light-transmitting substrate satisfies:

21. The method for manufacturing the light emitting device according to claim 14, wherein a minimum depth of the cutting light beam at a position on the wafer being cut does not exceed ⅓

of a thickness of the light-transmitting substrate at a perpendicular direction, the perpendicular direction is parallel to a normal vector of the upper surface.

22. The method for manufacturing the light emitting device according to claim 14, wherein in each of the light emitting devices, a ratio of a length of the long side to a length of the short side falls within a range of 1 to 20.

23. The method for manufacturing the light emitting device according to claim 14, wherein each of the light-transmitting substrates is formed by a crystalline material, the crystalline material comprises a first crystal plane and a second crystal plane, the first direction is perpendicular to a normal vector of the first crystal plane, the second crystal plane is parallel to the upper surface, an included angle formed by the normal vector of the first crystal plane and a normal vector of the second crystal plane is greater than 90°

.

24. The method for manufacturing the light emitting device according to claim 23, wherein the crystalline material further comprises a third crystal plane, a normal vector of the third crystal plane is parallel to the second direction.

25. The method for manufacturing the light emitting device according to claim 23, wherein the first crystal plane is a (1012) crystal plane, and the second crystal plane is a (0001) crystal plane.

26. The method for manufacturing the light emitting device according to claim 23, wherein the crystalline material is sapphire.