Dielectric film coating for full conversion ceramic platelets
A wavelength converter may include a phosphor layer and a filter layer where the filter layer may be directly attached to the phosphor layer. The wavelength converter may have an overall thickness ranging from 20 μm to 80 μm. A light emitting device assembly and methods for preparing a wavelength converter and methods for preparing a light emitting device assembly are also disclosed.
1. A wavelength converter comprising:
a phosphor layer; and
a filter layer;
wherein the filter layer is directly attached to the phosphor layer and wherein the filter layer comprises:
a first plurality of sublayers comprising at least one first metal oxide and,
a second plurality of sublayers comprising at least one second metal oxide,
wherein the at least one first metal oxide is different from the at least one second metal oxide,
wherein a first sublayer of the first plurality of sublayers is arranged furthest away from the phosphor layer and comprises a first thickness,
wherein at least one second sublayer of the first plurality of sublayers comprises a second thickness,
wherein the first thickness is at least 200% of the second thickness;
wherein the wavelength converter has an overall thickness ranging from 20 μm to 80 μm, and
wherein the at least one second sublayer comprising the second thickness is directly attached to the phosphor layer.
2. The wavelength converter of claim 1 , wherein a phosphor of the phosphor layer is selected from the group consisting of (Ba,Sr) 2 Si 5 N 8 :Eu 2+ , Ca-α-SiAlON:Eu 2+ , YAG:Ce+CaAlSiN 3 :Eu, (Ca,Sr)AlSiN 3 :Eu 2+ , (Sr,Ca)Al 2 Si 2 N 6 :Eu 2+ , (Ba,Sr,Ca) 2 Si 5 N 8 :Eu 2+ and Sr(LiAl 3 N 4 ):Eu 2+ .
3. The wavelength converter of claim 1 , wherein the at least one first metal oxide and the at least one second metal oxide are selected from the group consisting of SiO 2 , Al 2 O 3 , TiO 2 , Nb 2 O 5 , Ta 2 O 5 , HfO 2 , or Y 2 O 3 .
4. The wavelength converter of claim 1 , further comprising an absorption layer.
5. The wavelength converter of claim 4 , wherein the absorption layer comprises an ion doped color filter glasses selected from the group comprising MoS 2 dyed glasses, Ce-doped Gallium-Gadolinium-YAG, or selected from semiconductor materials.
6. The wavelength converter of claim 5 , wherein the semiconductor materials are selected from the group comprising GaP, AIP, AlAs, CdSe, or CdS; wherein the semiconductor materials comprise thin layers, nanoparticles, or combinations thereof.
7. The wavelength converter of claim 1 , wherein the first plurality of sublayers further comprises at least one third sublayer with a third thickness, wherein the third thickness is between 150% and 200% of the second thickness and wherein the first thickness is between 150% and 200% of the third thickness.
8. The wavelength converter of claim 7 , wherein the third sublayer of the first plurality of sublayers is arranged between the first sublayer and the at least one second sublayer.
9. The wavelength converter of claim 1 , wherein the second thickness comprises the smallest sublayer thickness of the first plurality of sublayers.