Thin film wavelength converters and methods for making the same
Thin film wavelength converters and methods for making the same are disclosed. In some embodiments, the thin film converters include a first thin film layer of first wavelength conversion material, a conductive layer, and a second thin film layer of a second wavelength conversion material. In one embodiment, a photoresist mask is applied to the conductive layer to form a pattern of by which the second wavelength conversion material may be applied by electrophoretic deposition to the exposed regions of the surface of the conductive layer.
1. A thin film wavelength converter, comprising:
a substrate;
a first thin film layer, said first thin film layer comprising at least one first wavelength conversion material;
an electrically conductive layer; and
a second thin film layer deposited on said electrically conductive layer, said second thin film layer comprising at least one second wavelength conversion material;
wherein:
said first thin film layer is configured to convert incident primary light from a light source in a first wavelength range to secondary light in a second wavelength range; and
said second thin film layer is configured to convert at least one of said primary light and said secondary light to tertiary light in a third wavelength range, said second wavelength range being different from said third wavelength range; and wherein the first thin film layer has a thickness ranging from about 10 nanometers (nm) to about 20 micrometers (μm).
2. The thin film wavelength converter of claim 1 , wherein said first wavelength conversion material is selected from the group consisting of garnet phosphors, oxynitride phosphors, nitride phosphors, silicate phosphors, and combinations thereof.
3. The thin film wavelength converter of claim 1 , wherein the at least one second wavelength conversion material is chosen from Y 3 Al 5 O 12 :Ce 3+ , Lu 3 Al 5 O 12 :Ce 3+ , Tb 3 Al 5 O 12 :Ce 3+ , M 2 Si 5 N 8 :Eu 2+ MSi 2 O 2 N 2 :Eu 2+ , BaMgSi 4 O 10 :Eu 2+ , M 2 SiO 4 :Eu 2+ , MAlSiN 3 :Eu 2+ and combinations thereof, wherein M is chosen from calcium, barium, strontium, and combinations thereof.
4. The thin film wavelength converter of claim 1 , wherein said second thin film layer comprises islands of said at least of second wavelength conversion material on said conductive layer.
5. The thin film wavelength converter of claim 1 , wherein said substrate comprises an upper and lower surface and said first thin film layer is deposited on the upper surface and the conductive layer is deposited on the first thin film layer.
6. The thin film wavelength converter of claim 1 , wherein said substrate comprises an upper and lower surface and said first thin film layer is deposited on the lower surface and the conductive layer is deposited on the upper surface.
7. The thin film wavelength converter of claim 1 , wherein said substrate is formed from a material selected from the group consisting of sapphire, at least one phosphor ceramic, polycrystalline transparent alumina, aluminum nitride, yttria stabilized zirconia (YSZ), zirconium oxides, gallium nitride, aluminum gallium nitride (AlGaN), and indium gallium nitride (InGaN).
8. The thin film wavelength converter of claim 1 , wherein said conductive layer is comprised of at least one of: a metal film, indium tin oxide (ITO), aluminum-doped zinc oxide (ZnO:Al), gallium-doped zinc oxide, niobium-doped strontium titanium oxide (SrTiO 3 :Nb), indium gallium zinc oxide (IGZO).