Color conversion arrangement, a lighting unit, a solid state light emitter package and a luminaire

A lighting unit comprising:

• a housing enclosing a cavity and comprising a light exit window, wherein at least a portion of the housing comprising a heat conductive material;
• a light emitter disposed in the cavity and configured to emit light of a first color;
• a color conversion arrangement disposed within the housing above the cavity and configured to convert the light of the first color to light of another color, the color conversion arrangement comprising:
• (i) a first luminescent layer comprising a first luminescent material configured to absorb a portion of light of a first spectral distribution comprising the first color and configured to convert at least a portion of the absorbed light towards light of a second spectral distribution;
• (ii) a supporting layer configured to support the first luminescent layer;
• and (iii) a first graphene layer configured to thermally conduct heat in a lateral direction to reduce temperature differences in the color conversion arrangement, wherein:
• i) the supporting layer is formed by a layer of the light emitter, wherein a stack of the first luminescent layer and the first graphene layer is provided on the supporting layer, and wherein a light emitting surface of the supporting layer is in contact with either the first luminescent layer or the first graphene layer;
• or
• ii) the supporting layer comprises a first side and a second side being opposite the first side, and the first graphene layer is provided at the first side of the supporting layer, wherein the first graphene layer is thermally coupled to the supporting layer, and the first luminescent layer is provided at the second side of the supporting layer, and further wherein the first luminescent layer is thermally coupled to the supporting layer;
• or
• iii) the color conversion arrangement comprises a second graphene layer, and the first luminescent layer is sandwiched between the first graphene layer and the second graphene layer, and wherein a stack of the first and second graphene layers and first luminescent layer is provided on the supporting layer;
• or
• iv) the color conversion arrangement comprises a second luminescent layer comprising a second luminescent material configured to absorb a portion of light of a third spectral distribution comprising the first color and/or light of the second spectral distribution, wherein the second luminescent material is configured to convert at least a portion of the absorbed light towards light of a fourth spectral distribution, and wherein the first graphene layer is sandwiched between the first luminescent layer and the second luminescent layer and a stack of the luminescent layers and the first graphene layer is provided on the supporting layer;
• and
• wherein the color conversion arrangement is provided at the light exit window, and the first graphene layer and/or the second graphene layer is thermally coupled to the portion of the housing of the heat conductive material.