WAVELENGTH CONVERTING LAYER PATTERNING FOR LED ARRAYS

• US 20190198721A1
• Filed: 12/19/2018
• Published: 06/27/2019
• Est. Priority Date: 12/22/2017
• Status: Active Grant

• Current Assignee: Lumileds LLC (Apollo Global Management, Inc.)
• Original Assignee: Lumileds LLC (Apollo Global Management, Inc.)
• Inventors: CHAMBERLIN, Danielle Russell, ROELING, Erik Maria, ROITMAN, Daniel Bernardo, SHIMIZU, Kentaro
• Granted Patent: US 10,879,431 B2
• Time in Patent Office: Days
• CPC Class Codes: C09K 11/025 non-luminescent particle coatings or suspension media
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 2933/0041 relating to wavelength conversion 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 33/24 of the light emitting region, e.g. non-planar junction
• CPC Class Codes: H01L 33/32 containing nitrogen
• CPC Class Codes: H01L 33/44 characterised by the coatings, e.g. passivation layer or anti-reflective coating
• CPC Class Codes: H01L 33/46 Reflective coating, e.g. dielectric Bragg reflector
• CPC Class Codes: H01L 33/501 characterised by the materials, e.g. binder
• CPC Class Codes: H01L 33/502 Wavelength conversion materials
• CPC Class Codes: H01L 33/505 characterised by the shape, e.g. plate or foil

Abstract

A wavelength converting layer is disclosed that includes a plurality of phosphor grains 50-500 nm in size and encapsulated in cerium free YAG shells and a binder material binding the plurality of phosphor grains, the wavelength converting layer having a thickness of 5-20 microns attached to the light emitting surface.

Claims

1. A method comprising:

depositing a wavelength converting layer onto a surface, the wavelength converting layer comprising a photoinitiator and a binder material; and

patterning the wavelength converting layer by applying a nanoimprint lithography process to the wavelength converting layer, the nanoimprint lithography process comprising;

applying a nanoimprint mold on the wavelength converting layer;

curing the wavelength converting layer such that the photoinitiator experiences decarboxylation; and

removing the nanoimprint mold from the wavelength converting layer after the curing.

2. The method of claim 1, wherein the decarboxylation produces a super base.

3. The method of claim 2, wherein the super base causes catalytic action on one of a reactive chain ends and a crosslinkable substrates of the binder material.

4. The method of claim 1, wherein the binder material experiences one of a condensation polymerization and a ring opening polymerization during the curing.

5. The method of claim 1, wherein the wavelength converting layer is cured with ultraviolet (UV) light.

6. The method of claim 1, wherein the photoinitiator is a salt generated by interactions of one or more bases with an acid.

7. The method of claim 2, further comprising removing the super base using one of a thermal cure and a postbake.

8. The method of claim 1, further comprising applying a first converter film to a first light emitting device and a second converter film to a second light emitting device such that the first converter film and the second converter film are segments of the wavelength converting layer generated by patterning the wavelength converting layer.

9. The method of claim 1, wherein the binder material comprises one or more of a siloxane material, a polysilazane, or a sol-gel material.

10. The method of claim 1, wherein the wavelength converting layer further comprises a plurality of optically isolating particles.

11. A device comprising:

a plurality of GaN mesas;

a mesh wall in contact with the GaN mesas; and

a wavelength converting layer deposited into a plurality of cavities in the mesh wall.

12. The device of claim 11, wherein the converter material is deposited into a first cavity and a second cavity, of the plurality of cavities, by at least one of die coating, blade coating, spray coating, or lamination.

13. The device of claim 11, wherein the wavelength converting layer comprises phosphor particles.

14. The device of claim 11, wherein the mesh wall'"'"'s structure is created by one of a direct ultraviolet (UV) nanoimprint lithography process, a thermal nanoimprint lithography process, and a contact print process

15. The device of claim 11, wherein a first cavity of the plurality of cavities is less than 100 micro meters wide.

16. A device comprising:

a first wavelength converting layer on a surface, the first wavelength converting layer comprising a photoinitiator, and a binder material selected from one or more of a siloxane material, a polysilazane, and a sol-gel material;

a second wavelength converting layer on the surface, the second wavelength converting layer comprising a plurality of optically isolating particles, a decarboxylated photoinitiator, and a binder material selected from one or more of a siloxane material, a polysilazane, and a sol-gel material; and

a super base.

17. The device of claim 16, further comprising a nano-imprint mold.

18. The device of claim 16, wherein the first wavelength converting layer and the second wavelength converting layer are part of the same original wavelength converting layer and the second wavelength converting layer is a portion of the original wavelength converting layer that experienced curing via decarboxylation.

19. The device of claim 16, wherein the decarboxylated photoinitiator is decarboxylated via UV light.

20. The device of claim 16, wherein the super base is created by decarboxylation.