Self-supporting wavelength-converting phosphor layer
A layer of multiple phosphor particles is formed on a surface of a substrate, and inorganic material is formed or deposited to embed at least partially the layer of phosphor particles on the substrate. A wavelength-converting layer is thus formed, including the phosphor particles and the inorganic material, that is then separated from the substrate. The inorganic material binds together the phosphor particles so that the wavelength-converting layer is self-supporting. In some examples, before separating the wavelength-converting layer from the substrate, a release member can be adhered to a surface of the wavelength-converting layer opposite the substrate; the wavelength-converting layer can remain adhered to the release member after separation from the substrate. In some examples the wavelength-converting layer can be adhered to a light-emitting surface of a semiconductor light-emitting device.
1. A method comprising:
forming on a surface of a substrate a layer of multiple phosphor particles;
forming or depositing inorganic material that at least partially embeds the layer of phosphor particles on the substrate so as to form a wavelength-converting layer comprising the phosphor particles and the inorganic material, the wavelength-converting layer having a first surface against the substrate surface and a second surface opposite the first surface; and
separating the wavelength-converting layer from the substrate, the inorganic material binding together the phosphor particles so that the wavelength-converting layer is self-supporting.
2. The method of claim 1 further comprising adhering the wavelength-converting layer to a light-emitting surface of a semiconductor light-emitting device.
3. The method of claim 2 further comprising:
before separating the wavelength-converting layer from the substrate, adhering to the second surface of the wavelength-converting layer a release member, the wavelength-converting layer remaining adhered to the release member after separation from the substrate; and
after adhering the wavelength-converting layer to the light-emitting device with the first surface of the wavelength-converting layer against the light-emitting surface, separating the release member from the wavelength-converting layer, the wavelength-converting layer remaining adhered to the light-emitting device after separation from the release member.
4. The method of claim 2 , the wavelength-converting layer being adhered to the light-emitting surface by only one of: (i) an intervening layer of polymeric adhesive; (ii) an intervening layer of inorganic material having substantially the same chemical composition as the inorganic material binding together the phosphor particles of the wavelength-converting layer, and having a mean thickness between the light-emitting surface and those phosphor particles nearest the light-emitting surface that is substantially less than a mean thickness between adjacent phosphor particles within the wavelength-converting layer; or (iii) an intervening layer of inorganic material that differs in chemical composition from the inorganic material binding together the phosphor particles of the wavelength-converting layer.
5. The method of claim 4 , wherein:
forming or depositing the inorganic material binding together the phosphor particles comprises employing an Atomic Layer Deposition process that includes one or both of at least one stage of providing a metal or metal oxide precursor or at least one stage of providing an oxygen source; and
one or more of the metal or metal oxide precursor, the oxygen source, or a reaction condition of one or more of the corresponding stages of the Atomic Layer Deposition process are damaging to the semiconductor light-emitting device or the light-emitting surface thereof.
6. The method of claim 2 , wherein separating the wavelength-converting layer from the substrate and adhering the wavelength-converting layer to the light-emitting surface of the semiconductor light-emitting device includes employing a substrate-free transfer process.
7. The method of claim 1 , the wavelength-converting layer having a non-zero mean thickness less than about 0.10 millimeters.
8. The method of claim 1 , at least a portion of the substrate surface exhibiting low wettability or negligible reactivity with respect to reagents employed for forming or depositing the inorganic material binding together the phosphor particles.
9. The method of claim 1 , the substrate surface including one or more of polytetrafluoroethylene, at least one perfluoroalkoxy alkane, or at least one fluorinated ethylene propylene.
10. The method of claim 1 , a D50 value of a particle size distribution of the phosphor particles being between about 1.0 μm and about 50. μm.
11. The method of claim 1 , wherein forming or depositing the inorganic material binding together the phosphor particles comprises employing an Atomic Layer Deposition process that includes one or both of at least one stage of providing a metal or metal oxide precursor or at least one stage of providing an oxygen source.
12. The method of claim 1 , the wavelength-converting layer including a plurality of voids, the plurality of voids occupying between about 1.0% and about 30.% of overall volume of the wavelength-converting layer.
13. A wavelength-converting layer comprising:
a multitude of phosphor particles;
inorganic material, different from material of the phosphor particles, arranged so as to embed at least partially the phosphor particles and form the wavelength-converting layer, the inorganic material binding together the phosphor particles so that the wavelength-converting layer is self-supporting.
14. The wavelength-converting layer of claim 13 further comprising a release member adhered to a first surface of the wavelength-converting layer, a second, opposite surface of the wavelength-converting layer being exposed and free of any attached layer, member, or device.
15. A wavelength-converted light-emitting device incorporating the wavelength-converting layer of claim 13 , comprising:
a semiconductor light-emitting device having a light-emitting surface;
the wavelength-converting layer of claim 13 adhered to the light-emitting surface of the semiconductor light-emitting device; and
an intervening layer of polymeric adhesive positioned between the light-emitting surface and the wavelength-converting layer and adhering the wavelength-converting layer to the light-emitting surface.
16. A wavelength-converted light-emitting device incorporating the wavelength-converting layer of claim 13 , comprising:
a semiconductor light-emitting device having a light-emitting surface;
the wavelength-converting layer of claim 13 adhered to the light-emitting surface of the semiconductor light-emitting device; and
an intervening layer positioned between the light-emitting surface and the wavelength-converting layer and adhering the wavelength-converting layer to the light-emitting surface, the intervening layer comprising inorganic material having (i) substantially the same chemical composition as the inorganic material binding together the phosphor particles of the wavelength-converting layer and (ii) a mean thickness between the light-emitting surface and those phosphor particles nearest the light-emitting surface that is substantially less than a mean thickness between adjacent phosphor particles within the wavelength-converting layer.
17. A wavelength-converted light-emitting device incorporating the wavelength-converting layer of claim 13 , comprising:
a semiconductor light-emitting device having a light-emitting surface;
the wavelength-converting layer of claim 13 adhered to the light-emitting surface of the semiconductor light-emitting device; and
an intervening layer positioned between the light-emitting surface and the wavelength-converting layer and adhering the wavelength-converting layer to the light-emitting surface, the intervening layer comprising inorganic material that differs in chemical composition from the inorganic material binding together the phosphor particles of the wavelength-converting layer.
18. The wavelength-converting layer of claim 13 , the wavelength-converting layer having a non-zero mean thickness less than about 0.10 millimeters.
19. The wavelength-converting layer of claim 13 , a D50 value of a particle size distribution of the phosphor particles being between about 1.0 μm and about 50. μm.
20. The wavelength-converting layer of claim 13 , the wavelength-converting layer including a plurality of voids, the plurality of voids occupying between about 1.0% and about 30.% of overall volume of the wavelength-converting layer.