Dense-luminescent-materials-coated violet LEDs

• US 9,761,763 B2
• Filed: 12/19/2013
• Issued: 09/12/2017
• Est. Priority Date: 12/21/2012
• Status: Active Grant

• Current Assignee: Korrus Incorporated (MKD Electric, Inc.)
• Original Assignee: Soraa, Inc.
• Inventors: Steranka, Frank M., Aldaz, Rafael, Ankireddi, Seshasayee, Trottier, Troy, Modi, Rohit, Saha, Rajarshi
• Primary Examiner(s): Cao, Phat X
• Assistant Examiner(s): Hoque, Mohammad M
• Application Number:
  US14/135,098
• Publication Number:
  US 20140175492A1
• Time in Patent Office: 1,363 Days
• Field of Search: 257 98, 438 28
• CPC Class Codes: F21K 9/233 specially adapted for generating a spot light distribution, e.g. for substitution of reflector lamps
• CPC Class Codes: F21S 41/155 Surface emitters, e.g. organic light emitting diodes [OLED]
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• 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 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/12044 OLED
• CPC Class Codes: H01L 2933/0041 relating to wavelength conversion elements
• CPC Class Codes: H01L 33/20 with a particular shape, e.g. curved or truncated substrate
• CPC Class Codes: H01L 33/44 characterised by the coatings, e.g. passivation layer or anti-reflective coating
• CPC Class Codes: H01L 33/50 Wavelength conversion elements

Abstract

Techniques for fabricating and using arrays of violet-emitting LEDs coated with densely-packed-luminescent-material layers together with apparatus and method embodiments thereto are disclosed.

Claims

1. An apparatus comprising:

a submount;

at least one LED die attached to the submount, wherein the perimeter of the LED die defines a plurality of sides; and

a conformal coating over the plurality of sides to define a thickness on each of the sides, and comprising at least one luminescent material;

wherein at least one of the LED die or the thickness of the conformal coating on the sides of the LED die is configured such that light emitted from each of the sides has a chromaticity with a Du′

v′

that varies by no more than 0.015 from the Du′

v′

of the light of the other sides.

2. The apparatus of claim 1, wherein the thickness of the conformal coating varies among the plurality of sides.

3. The apparatus of claim 2, wherein the plurality of sides comprises a top side and a plurality of lateral sides, wherein the thickness of the conformal coating on the lateral sides is thicker than the top side.

4. The apparatus of claim 3, wherein the thickness of the conformal coating varies among the lateral sides.

5. The apparatus of claim 1, wherein the LED die is a violet-emitting die.

6. The apparatus of claim 5, wherein the current density in the at least one LED die is 175 Amps/cm².

7. The apparatus of claim 1, wherein the at least one LED die comprises a first LED die and a second LED die having different spectra.

8. The apparatus of claim 1, further comprising reflective dam around the at least one LED die.

9. The apparatus of claim 8, wherein a portion of the conformal coating is between at least one of the plurality of sides and the reflective dam.

10. The apparatus of claim 1 further comprising at least one optical element disposed over the at least one LED die.

11. The apparatus of claim 10, wherein the at least one optical element is a lens.

12. The apparatus of claim 11, wherein the lens is a silicone encapsulant.

13. The apparatus of claim 12, wherein the silicone encapsulant is at least partially spherical.

14. The apparatus of claim 1, where the at least one LED die comprises at least a first LED die and a second LED die forming at least one linear array.

15. The apparatus of claim 1, wherein at least one face of the at least one LED die is aligned to be substantially parallel to a long edge of the submount.