Method and apparatus of applying light and heat to quantum dots to increase quantum yield

Patent metadata

Field	Value
Publication number	US-10544313-B2
Application number	US-201715425920-A
Country	US
Kind code	B2
Filing date	Feb 6, 2017
Priority date	Feb 4, 2016
Publication date	Jan 28, 2020
Grant date	Jan 28, 2020

Abstract

A method of increasing photo-luminescent quantum yield (PLQY) of QDs to be used as down-converters placed directly on an LED chip includes synthesizing a plurality of quantum dots, applying energy to the plurality of quantum dots to increase PLQY of the plurality of quantum dots, dispensing the plurality of quantum dots onto the LED chip, and curing the LED chip.

First claim

What is claimed is:

1. A method of increasing photo-luminescent quantum yield (PLQY) of quantum dots (QDs), comprising:
synthesizing a plurality of quantum dots; and
applying heat from a heat source and light from a light source different than the heat source, for a duration of time selected from a range from 15 minutes to 100 hours, to the plurality of quantum dots to increase PLQY of the plurality of quantum dots prior to, during, or after further processing, at any point in time between a time that the quantum dot particles are synthesized and a time that a light emitting diode (LED) chip, onto which the QDs are deposited, is first operated.

2. The method of claim 1 , further comprising:
dispensing the plurality of quantum dots onto the Light Emitting Diode (LED) chip; and
curing the LED chip.

3. The method of claim 2 , wherein dispensing the plurality of quantum dots onto the LED chip comprises:
mixing the plurality of quantum dots into a polymer slurry; and
dispensing the polymer slurry onto the LED chip.

4. The method of claim 3 , wherein applying heat and light to the plurality of quantum dots comprises applying heat and light to the plurality of quantum dots prior to mixing the plurality of quantum dots into the polymer slurry.

5. The method of claim 3 , wherein applying heat and light to the plurality of quantum dots comprises applying heat and light to the plurality of quantum dots after mixing the plurality of quantum dots into the polymer slurry.

6. The method of claim 3 , wherein applying heat and light to the plurality of quantum dots comprises applying heat and light to the plurality of quantum dots after dispensing the polymer slurry onto the LED chip.

7. The method of claim 3 , wherein the polymer slurry comprises a first part and a second part, and wherein mixing the plurality of quantum dots into a polymer slurry comprises:
mixing the plurality of quantum dots into the first part of the polymer slurry; and
mixing the plurality of quantum dots mixed with the first part of the polymer slurry into the second part of the polymer slurry.

8. The method of claim 7 , wherein applying heat and light to the plurality of quantum dots comprises applying heat and light to the plurality of quantum dots after mixing the plurality of quantum dots into the first part of the polymer slurry but before mixing the plurality of quantum dots mixed with the first part of the polymer slurry into the second part of the polymer slurry.

9. The method of claim 2 , further comprising surface mounting the LED chip onto a substrate, and wherein applying heat and light to the plurality of quantum dots to increase PLQY of the plurality of quantum dots comprises applying heat and light to the plurality of quantum dots after surface mounting the LED chip onto the substrate.

10. The method of claim 2 , further comprising drying the plurality of quantum dots to produce a plurality of quantum dots in powder form.

11. The method of claim 10 , wherein applying heat and light to the plurality of quantum dots to increase PLQY of the plurality of quantum dots comprises applying heat and light to the plurality of quantum dots prior to drying the plurality of quantum dots to produce a plurality of quantum dots in powder form.

12. The method of claim 10 , wherein dispensing the plurality of quantum dots onto the LED chip comprises:
mixing the plurality of quantum dots in powder form into a polymer slurry; and
dispensing the polymer slurry onto the LED chip.

13. The method of claim 12 , wherein applying heat and light to the plurality of quantum dots comprises applying heat and light to the plurality of quantum dots in powder form prior to mixing the plurality of quantum dots in powder form into the polymer slurry.

14. The method of claim 12 , wherein applying heat and light to the plurality of quantum dots comprises applying heat and light to the plurality of quantum dots after mixing the plurality of quantum dots in powder form into the polymer slurry.

15. The method of claim 12 , wherein applying heat and light to the plurality of quantum dots comprises applying heat and light to the plurality of quantum dots after dispensing the polymer slurry onto the LED chip.

16. The method of claim 12 , wherein the polymer slurry comprises a first part and a second part, and wherein mixing the plurality of quantum dots in powder form into a polymer slurry comprises:
mixing the plurality of quantum dots in powder form into the first part of the polymer slurry; and
mixing the plurality of quantum dots in powder form mixed with the first part of the polymer slurry into the second part of the polymer slurry.

17. The method of claim 16 , wherein applying heat and light to the plurality of quantum dots comprises applying heat and light to the plurality of quantum dots in powder form after mixing the plurality of quantum dots in powder form into the first part of the polymer slurry but before mixing the plurality of quantum dots in powder form mixed with the first part of the polymer slurry into the second part of the polymer slurry.

18. The method of claim 10 , further comprising surface mounting the LED chip onto a substrate, and wherein applying heat and light to the plurality of quantum dots to increase PLQY of the plurality of quantum dots comprises applying heat and light to the plurality of quantum dots after surface mounting the LED chip onto the substrate.

19. A method of increasing photo-luminescent quantum yield (PLQY) of quantum dots (QDs), comprising:
synthesizing a plurality of quantum dots;
applying heat from a heat source and light from a light source different than the heat source, for a duration of time selected from a range from 15 minutes to 100 hours, to the plurality of quantum dots to increase the PLQY of the plurality of quantum dots prior to, during, or after further processing;
dispensing the plurality of quantum dots onto a Light Emitting Diode (LED) chip comprising:
mixing the plurality of quantum dots into a first part of a polymer slurry;
mixing the plurality of quantum dots mixed with the first part of the polymer slurry into a second part of the polymer slurry; and
dispensing the polymer slurry onto the LED chip; and

curing the LED chip.

Assignees

• Pacific Light Tech Corp
• Osram Opto Semiconductors Gmbh

Inventors

• Mclaughlin Nathan
• Haley Kari N
• Vonnahme Morgan
• Theobald Brian
• Puetz Norbert

Classifications

• Y10S977/774

  Exhibiting three-dimensional carrier confinement, e.g. quantum dots · CPC title

• C09K11/883

  with zinc or cadmium · CPC title

• B82Y40/00

  Manufacture or treatment of nanostructures · CPC title

• C09D5/22 Primary

  Luminous paints {(luminescent compositions C09K11/00)} · CPC title

• Y10S977/95

  Electromagnetic energy · CPC title