| abstract |
The invention provides a lighting device configured to provide red lighting device light, the lighting device comprising: (i) a first light source configured to provide first light source light having a peak wavelength (λls); (ii) a first red luminescent material configured to absorb at least part of the first light source light and to convert into first red luminescent material light having a first red emission peak wavelength (λm1), the first red luminescent material having an excitation maximum (λx1); (iii) a second red luminescent material configured to absorb at least part of the first light source light and to convert into second red luminescent material light having a second red emission peak wavelength (λm2), the second red luminescent material having a second excitation maximum (λx2); and wherein the first luminescent material and the second luminescent material are Eu2+ based, and wherein λm1<λm2, λx1<λls and λx2>λls. |