Methods and systems for fabricating broad spectrum light emitting devices
View Patent ↗Broad spectrum light emitting devices and methods and systems for fabricating such devices are provide. Such devices may include a light emitting element, such as a diode or laser, which emits light in a predefined range of frequencies, and luminous material on the light emitting diode. The characteristics of the luminous material, such as the amount, composition and/or doping of the luminous material or materials may be based on measured light output of the light emitting device, such as the measured output frequency and/or power of the light emitting device.
1. A method of fabricating a light emitting apparatus, comprising:
measuring light output of respective ones of a plurality of semiconductor light emitting devices; then
sorting the semiconductor light emitting devices based on the measured light output of the semiconductor light emitting devices so as to provide a plurality of groups of semiconductor light emitting devices, a respective group comprising a plurality of semiconductor light emitting devices having similar measured light output characteristics; and then
tailoring luminous material in a respective group of semiconductor light emitting devices in common.
2. The method of claim 1 , wherein tailoring luminous material comprises selectively removing a same amount of previously applied luminous material from the semiconductor light emitting devices in the respective group.
3. The method of claim 1 , wherein measuring light output of respective ones of a plurality of semiconductor light emitting devices comprises measuring a frequency of light output of respective ones of a plurality of semiconductor light emitting devices.
4. The method of claim 1 , wherein measuring light output of respective ones of the plurality of semiconductor light emitting devices is preceded by applying a common coating of luminous material to the plurality of semiconductor light emitting devices.
5. The method of claim 1 , wherein the plurality of semiconductor light emitting devices are configured to generate light from electricity and wherein the luminous material is optically excited by the light that is generated by the light emitting devices.
6. The method of claim 1 , wherein the plurality of light emitting devices are on a wafer.
7. The method of claim 1 , wherein tailoring luminous material comprises selectively applying a same amount of luminous material to the semiconductor light emitting devices in the respective group.
8. The method of claim 7 , wherein selectively applying a same amount of luminous material comprises selectively applying different compositions of the same amount of luminous material to the plurality of semiconductor light emitting devices in the respective groups.
9. The method of claim 7 , wherein selectively applying a same amount of luminous material comprises selectively applying differing doping levels of the same amount of luminous material to the plurality of semiconductor light emitting devices in the respective groups.
10. The method of claim 7 , wherein selectively applying luminous material is preceded by singulating the light emitting devices from a wafer.
11. The method of claim 7 , wherein selectively applying a same amount of luminous material comprises selectively applying a same amount of luminous material utilizing at least on of an inkjet application process, an air brush application process, a fluid application process, electrostatic deposition, electrophoretic deposition, screen printing, dipping, roll coating and/or vacuum deposition.
12. The method of claim 1 , wherein measuring light output of respective ones of a plurality of semiconductor light emitting devices comprises:
activating respective ones of the plurality of semiconductor light emitting devices; and
measuring light output of the respective ones of the plurality of semiconductor light emitting devices when the respective ones of the semiconductor light emitting devices are activated.
13. The method of claim 12 , wherein the respective ones of the plurality of semiconductor light emitting devices have two contacts accessible from a single side of the device, and wherein activating respective ones of the plurality of semiconductor light emitting devices comprises:
placing the respective ones of the plurality of semiconductor light emitting devices on a conductive foil; and
contacting the respective ones of the plurality of semiconductor light emitting devices through the foil.
14. The method of claim 1 , wherein tailoring is followed by:
further measuring light output of the semiconductor light emitting devices in the respective group;
further tailoring luminous material in the respective group of semiconductor light emitting devices in common; and
repeating the further measuring and the further tailoring until a predefined light output criteria for the respective group is reached.
15. The method of claim 14 , wherein the predefined light output criteria comprises a substantially uniform light output of the plurality of semiconductor light emitting devices in the plurality of groups.
16. The method of claim 1 , wherein the light emitting devices are gallium nitride based light emitting devices.
17. The method of claim 16 , wherein the light emitting devices include a silicon carbide substrate, wherein light is extracted through the silicon carbide substrate and wherein the luminous material is applied to the silicon carbide substrate.