DENSE-LUMINESCENT-MATERIALS-COATED VIOLET LEDS

• US 20140175492A1
• Filed: 12/19/2013
• Published: 06/26/2014
• Est. Priority Date: 12/21/2012
• Status: Active Grant

• Current Assignee: Korrus Incorporated (MKD Electric, Inc.)
• Original Assignee: Soraa, Inc.
• Inventors: STERANKA, FRANK M., ANKIREDDI, SESHASAYEE, ALDAZ, RAFAEL, TROTTIER, TROY, MODI, ROHIT, SAHA, RAJARSHI
• Granted Patent: US 9,761,763 B2
• Time in Patent Office: Days
• US Class Current: 257/98
• 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. A method for coating violet-emitting LED die with densely-packed-luminescent-materials, comprising:

attaching an arrangement of a one or more violet-emitting LED die to a submount structure;

applying a photoresist characterized by a thickness greater than a height of at least some of the one or more violet-emitting LED die;

opening a first cavity hole in the photoresist around at least some of the one or more violet-emitting LED die;

dispensing a luminescent material into the first cavity hole; and

stripping the photoresist to provide one or more densely-packed-luminescent-materials coated violet-emitting LED die.

2. The method of claim 1, wherein the violet-emitting LEDs are grown on a bulk-GaN substrate.

3. The method of claim 1, further comprising:

applying a second photoresist over the one or more densely-packed-luminescent-materials coated LED die, wherein a height of the second photoresist is greater than a height of the one or more densely-packed-luminescent-materials coated violet-emitting LED die;

opening second cavity holes in the photoresist around at least some of the one or more violet-emitting LED die, wherein a width of the second cavity hole is greater than the width of the first cavity hole;

dispensing a second luminescent material into the second cavity hole; and

stripping the second photoresist to provide one or more densely-packed-luminescent-materials coated violet-emitting LED die comprising two luminescent-materials-containing layers.

4. The method of claim 1, wherein a height of the photoresist above the one or more violet-emitting LED die is different than a distance from an edge of the stripping the photoresist to provide one or more densely-packed-luminescent-materials coated violet-emitting LED die to a photoresist cavity wall.

5. The method of claim 1, wherein different ones of the one or more violet-emitting LED die have red, green, and blue luminescent materials deposited around different ones or more violet-emitting LED die.

6. The method of claim 1, wherein different ones of the violet-emitting LED die have cool-white, warm-white, red, green, or blue luminescent-material coatings in a selected proportion to create a color-tunable-white-light source.

7. The method of claim 1, wherein the luminescent material is deposited in a linear strip configuration around a linear arrangement of violet-emitting LED die.

8. The method of claim 1, wherein the arrangement comprises a linear array of triangular-shaped LED die, wherein at least some of the triangular-shaped violet-emitting LED die are juxtaposed in a first strip of triangular-shaped violet-emitting LED die having one side of the triangular-shaped LED die facing a narrow side of the submount.

9. The method of claim 1, wherein the arrangement comprises a first strip of triangular-shaped LED die, wherein one side of the triangular-shaped violet-emitting LED die face a wide side of the submount.

10. The method of claim 1, further comprising an additional cavity opening step being performed after the one or more violet-emitting LED die have been coated with first luminescent material, and further coating the die with a second luminescent material.

11. The method of claim 1, further comprising forming through-hole vias to the submount.

12. The method of claim 1, further comprising dicing luminescent-material-coated violet-emitting LED die out of the submount as stand-alone violet-emitting LEDs.

13. The method of claim 1, wherein a reflective dam is placed around a set of luminescent-material-coated violet-emitting LED die.

14. An apparatus comprising:

a submount;

a violet-emitting LED die attached to the submount, wherein the perimeter of the die forms an area; and

a coating covering at least one surface of the violet-emitting LED die, wherein the coating comprises at least one luminescent material.

15. The apparatus of claim 14, further comprising a second violet-emitting LED die attached to the submount.

16. The apparatus of claim 14, further comprising one or more violet-emitting LED die attached to the submount.

17. The apparatus of claim 16, wherein the one or more violet-emitting LED die form at least one linear array.

18. The apparatus of claim 17, wherein at least one face of the one or more violet-emitting LED die is aligned to be substantially parallel to a long edge of a rectangular-shaped submount.

19. The apparatus of claim 14, wherein the current density in the violet-emitting LED die is at least 175 Amps/cm².

20. An apparatus comprising:

a lamp base;

a submount;

a violet-emitting LED die attached to the submount and electrically connected to the lamp base, wherein the perimeter of the violet-emitting LED die forms a triangular area; and

a coating covering at least one surface of the violet-emitting LED die, wherein the coating comprises at least one luminescent material.