Methods of fabricating light emitting devices including multiple sequenced luminophoric layers
View Patent ↗An LED includes a first pedestal and may be fabricated by coating a first phosphor layer on the LED, thinning the first phosphor layer to expose the first pedestal, forming a second pedestal on the first pedestal, coating a second phosphor layer and thinning the second phosphor layer to expose the second pedestal. Alternatively, an LED having a pedestal is coated with a first phosphor layer, coated with a second phosphor layer and then planarized to expose the pedestal. Related structures are also provided.
1. A method of fabricating a light emitting device, comprising:
providing a Light Emitting Diode (“LED”) including a first conductive pedestal that protrudes away from a face thereof;
coating a first luminophoric layer on the face including on the first conductive pedestal;
thinning the first luminophoric layer to expose the first conductive pedestal;
forming a second conductive pedestal on the first conductive pedestal that was exposed;
coating a second luminophoric layer on the first luminophoric layer and on the second conductive pedestal; and
thinning the second luminophoric layer to expose the second conductive pedestal.
2. A method according to claim 1 wherein coating the first luminophoric layer and coating the second luminophoric layer are performed using different luminophoric layer coating processes.
3. A method according to claim 1 wherein coating the first luminophoric layer and coating the second luminophoric layer both comprise syringe or nozzle dispensing.
4. A method according to claim 1 :
wherein the first luminophoric layer has a first absorption and emission spectra and the second luminophoric layer has a second absorption and emission spectra, and
wherein a shorter wavelength end of the emission spectrum of the second luminophoric layer overlaps with a longer wavelength end of the absorption spectrum of the first luminophoric layer.
5. A method according to claim 1 wherein providing an LED comprises providing a wafer including the LED.
6. A method according to claim 1 wherein providing an LED comprises providing an LED chip.
7. A method according to claim 4 wherein the LED has a peak emission wavelength in the blue region, the first luminophoric layer has a peak emission wavelength in the red region and the second luminophoric layer has a peak emission wavelength in the yellow region.
8. A method of fabricating a light emitting device, comprising:
providing a Light Emitting Diode (“LED”) including a conductive pedestal that protrudes away from a face thereof;
coating a first luminophoric layer on the face including on the conductive pedestal to provide a nonplanar first luminophoric layer;
coating a second luminophoric layer on the nonplanar first luminophoric layer and on the conductive pedestal; and then
planarizing the LED to expose the conductive pedestal.
9. A method according to claim 8 wherein coating the first luminophoric layer and coating the second luminophoric layer are performed using different luminophoric layer coating processes.
10. A method according to claim 8 wherein coating the first luminophoric layer comprises spray coating the first luminophoric layer and wherein coating the second luminophoric layer comprises syringe or nozzle dispensing the second luminophoric layer.
11. A method according to claim 8 :
wherein the first luminophoric layer has a first absorption and emission spectra and the second luminophoric layer has a second absorption and emission spectra, and
wherein a shorter wavelength end of the emission spectrum of the second luminophoric layer overlaps with a longer wavelength end of the absorption spectrum of the first luminophoric layer.
12. A method according to claim 8 wherein providing an LED comprises providing a wafer including the LED.
13. A method according to claim 8 wherein providing an LED comprises providing an LED chip.
14. A method according to claim 11 wherein the LED has a peak emission wavelength in the blue region, the first luminophoric layer has a peak emission wavelength in the red region and the second luminophoric layer has a peak emission wavelength in the yellow region.
15. A method of fabricating a light emitting device, comprising:
providing a Light Emitting Diode (“LED”) including a first conductive pedestal that protrudes away from a face thereof;
coating a first layer on the face including on the first conductive pedestal;
thinning the first layer to expose the first conductive pedestal;
forming a second conductive pedestal on the first conductive pedestal that was exposed;
coating a second layer on the first layer and on the second conductive pedestal; and
thinning the second layer to expose the second conductive pedestal.
16. A method according to claim 15 wherein coating the first layer and coating the second layer are performed using different coating processes.
17. A method of fabricating a light emitting device, comprising:
providing a Light Emitting Diode (“LED”) including a conductive pedestal that protrudes away from a face thereof;
coating a first layer on the face including on the conductive pedestal to provide a nonplanar first layer;
coating a second layer on the nonplanar first layer and on the conductive pedestal; and then
planarizing the LED to expose the conductive pedestal.
18. A method according to claim 17 wherein coating the first layer and coating the second layer are performed using different coating processes.