Phosphor placement in white light emitting diode assemblies

A Light Emitting Diode (LED) assembly comprising:

• a substrate;
• a LED die disposed on the substrate;
• a first volume of a first luminescent material that surrounds the LED die in a lateral dimension, wherein no part of the first volume is disposed directly above any part of the LED die, wherein the first luminescent material comprises a first phosphor material capable of emitting light having a first peak wavelength longer than 620 nanometers, wherein the first volume comprises substantially no phosphor material capable of emitting light having a peak wavelength shorter than approximately 620 nanometers;
• and
• a second volume of a second luminescent material that is disposed at least in part directly above the LED die, wherein the second luminescent material comprises a second phosphor material capable of emitting light having a second peak wavelength shorter than 620 nanometers, wherein the second volume comprises substantially no phosphor material capable of emitting light having a peak wavelength longer than approximately 620 nanometers.

A method of manufacturing an LED assembly, wherein the LED assembly comprises an LED die disposed on a substrate, wherein the LED die defines a right rectangular prism (RRP) having four side faces, a first peripheral side of the LED die lies in a first plane that is substantially coplanar with a first side face of the RRP, a second peripheral side of the LED die lies in a second plane that is substantially coplanar with a second side face of the RRP, a third peripheral side of the LED die lies in a third plane that is substantially coplanar with a third side face of the RRP, a fourth peripheral side of the LED die lies in a fourth plane that is substantially coplanar with a fourth side face of the RRP, the method of manufacturing comprising:

• (a) forming a first volume of a first luminescent material such that the first volume is disposed entirely outside the RRP and such that the first volume surrounds the RRP in a lateral dimension, wherein the first luminescent material comprises a first phosphor material capable of emitting light having a first peak wavelength longer than 620 nanometers, wherein the first volume comprises substantially no phosphor material capable of emitting light having a peak wavelength shorter than approximately 620 nanometers;
• and
• (b) forming a second volume of a second luminescent material that is disposed at least in part above the LED die within the RRP, wherein the second luminescent material comprises a second phosphor material capable of emitting light having a second peak wavelength shorter than 620 nanometers, wherein the second volume comprises substantially no phosphor material capable of emitting light having a peak wavelength longer than approximately 620 nanometers.