Composite material with photoluminescent material embedded in a transparent matrix

A composite material comprising at least one photoluminescent material embedded as a light source in a transparent matrix,

• wherein a refractive index (nP) of the at least one photoluminescent material and a refractive index (nM) of the matrix differ by at most ±0.2,
• the composite material is transparent in the visible spectral range,
• an absorption maximum of the photoluminescent material lies outside a region of the spectrum visible to a human eye,
• the matrix comprises a filler material comprising particles by which the refractive index (nM) of the matrix is adjusted, and
• at least one of:
• the photoluminescent material consists of particles having an average particle diameter of ≤400 nm and/or an average particle diameter of ≥800 nm, and
• the photoluminescent material comprises at least one inorganic phosphor selected from the group consisting of
• (M1-xEux)10(PO4)6(Cl,F)2, in which M is selected from one or more elements from the group Sr, Mg, Ca and Ba and x=0.01-0.12, and the phosphors contain one or both of the elements in the parentheses,
• M1-yEuyMgAl10O17, in which M is selected from one or more elements from the group Ba, Mg, Ca and Sr and y=0.01-0.9,
• (M1-pEup)6BP5O20, in which M is selected from one or more elements from the group Sr, Mg, Ca and Ba and p=0.01-0.9,
• (Sr1-qEuq)4Al14O25, in which q=0.01-0.9,
• Mg4Ge1-rMnr(O,F)6, in which r=0.001-0.06 and the formula can contain one or both of the elements in the parentheses, and
• M1-sEus(Mg1-tMnt)Al10O17, in which M is selected from one or more elements from the group Ba, Mg, Ca and Sr, s=0.01-0.7 and t=0.05-0.5.