Wavelength-converting casting composition and light-emitting semiconductor component
View Patent ↗The wavelength-converting casting composition is based on a transparent epoxy casting resin with a luminous substance admixed. The composition is used in an electroluminescent component having a body that emits ultraviolet, blue or green light. An inorganic luminous substance pigment powder with luminous substance pigments is dispersed in the transparent epoxy casting resin. The luminous substance is a powder of Ce-doped phosphors and the luminous substance pigments have particle sizes ≦20 μm and a mean grain diameter d 50 ≦5 μm.
1. Apparatus comprising:
a semiconductor body configured to emit electromagnetic radiation in a first wavelength range; and
a wavelength-converting casting composition positioned to receive the electromagnetic radiation from the semiconductor body and configured to convert some of the electromagnetic radiation from the first wavelength range to a second wavelength range,
wherein the casting composition comprises luminous substance pigments selected from the group consisting of garnets doped with rare earths; thiogallates doped with rare earths; aluminates doped with rare earths; and orthosilicates doped with rare earths, and
wherein the luminous substance pigments having grain sizes ≦20 μm and a median diameter ≦5 μm, wherein 50% of the pigments have a grain diameter greater than said median diameter and 50% of the pigments have a grain diameter less than said median diameter.
2. The apparatus of claim 1 , wherein the median diameter of the luminous substance pigments is between 1 and 2 micrometers.
3. The apparatus of claim 1 , wherein the luminous substance pigments comprise Ce-doped garnet material.
4. The apparatus of claim 1 , wherein the luminous substance pigments comprise YAG:Ce material.
5. The apparatus of claim 1 , wherein iron content in the casting composition is ≦20 ppm.
6. The apparatus of claim 1 , wherein the casting composition comprises epoxy resin and where the luminous substance pigments are dispersed within the epoxy resin.
7. The apparatus of claim 1 , wherein the luminous substance pigments are configured to convert the electromagnetic radiation from a ultraviolet, blue or green spectral range to a relatively longer wavelength.
8. The apparatus of claim 1 , wherein the casting composition further comprises light-scattering particles.
9. The apparatus of claim 1 , wherein the first spectral range emitted by the semiconductor body comprises a maximum at a wavelength between 420 nm and 460 nm.
10. The apparatus of claim 1 , wherein the first spectral range comprises ultraviolet, blue, or green.
11. The apparatus of claim 1 , wherein during operating the electromagnetic radiation remaining in the first spectral range mixes with the converted electromagnetic radiation in the second spectral range to produce a mixed color electromagnetic radiation output for the apparatus.
12. The apparatus of claim 11 , wherein the mixed color electromagnetic radiation output appears as white light.
13. The apparatus of claim 12 , wherein the first spectral range comprises blue and the second spectral range comprises yellow, which mix to produce the appearance of the white light.
14. The apparatus of claim 12 , wherein the first spectral range comprises blue and the second spectral range comprises green and red, all of which mix to produce the appearance of the white light.
15. The apparatus of claim 1 , wherein the casting composition is spaced from the semiconductor body.
16. The apparatus of claim 1 , wherein the casting composition is applied to the semiconductor body.
17. The apparatus of claim 16 , wherein the casting composition is applied directly to the semiconductor body as a layer.
18. The apparatus of claim 1 , further comprising a housing with a recess, and wherein the semiconductor body is positioned within the housing.
19. The apparatus of claim 16 , wherein the casting composition covers the semiconductor body in the recess.