Phosphor-converted light emitting device
A phosphor-converted light emitting device includes a light emitting diode (LED) on a substrate, where the LED comprises a stack of epitaxial layers comprising a p-n junction. A wavelength conversion material is in optical communication with the LED. According to one embodiment of the phosphor-converted light emitting device, a selective filter is adjacent to the wavelength conversion material, and the selective filter comprises a plurality of nanoparticles for absorbing light from the LED not down-converted by the wavelength conversion material. According to another embodiment of the phosphor-converted light emitting device, a perpendicular distance between a perimeter of the LED on the substrate and an edge of the substrate is at least about 24 microns. According to another embodiment of the phosphor-converted light emitting device, the LED comprises a mirror layer on one or more sidewalls thereof for reducing light leakage through the sidewalls.
1. A light emitting system for emitting white light, the system comprising:
(a) a first phosphor-converted light emitting device comprising a first light emitting diode (LED) die having a dominant wavelength in a range of about 425 nm to about 475 nm for blue light emission, the first LED die comprising a stack of epitaxial layers on a substrate with no intervening substrates, the stack of epitaxial layers forming a mesa region on the substrate; and
a wavelength conversion material in optical communication with the first LED die, the wavelength conversion material emitting green light when excited by the blue light from the first LED die,
wherein a perpendicular distance between a perimeter of the mesa region on the substrate and each edge of the substrate is at least about 34 microns and no greater than about 140 microns, and
wherein the first phosphor-converted light emitting device comprises a saturated color purity of at least about 95%;
(b) a second phosphor-converted light emitting device comprising:
a second LED die having a dominant wavelength in a range of about 425 nm to about 475 nm for blue light emission, and
a second wavelength conversion material in optical communication with the second LED die, the second wavelength conversion material emitting red light when excited by the blue light from the second LED die; and
(c) a third light emitting device consisting of:
a third LED die having a dominant wavelength in a range of about 425 nm to about 475 nm for blue light emission,
wherein the light emitting system emits white light.
2. The phosphor-converted light emitting device of claim 1 , wherein the perpendicular distance is at least about 44 microns.
3. The phosphor-converted light emitting device of claim 2 , wherein the perpendicular distance is at least about 64 microns.
4. The system of claim 1 , wherein the second phosphor-converted light emitting device has a saturated color purity of at least about 95%.
5. The system of claim 1 , wherein the wavelength conversion material in optical communication with the first LED die comprises an α-SiAlON ceramic doped with Eu 2+ , a β-SiAlON ceramic doped with Eu 2+ , Lu 3 Al 5 O 12 :Ce 3+ , LU 3-y Y y Al 5 O 12 :Ce 3+ , LU 3 Al 5-x Ga x O 12 :Ce 3+ , LU 3-y Gd y Al 5-x O 12 :Ce 3+ , and/or Lu 3-y Y y Al 5-x Ga x O 12 :Ce 3+ , where 0<y<3 and 0<x<5.