Thermal performance for spot lamps

A lighting device selected from the group of a lamp and a luminaire, the lighting device comprising:

• a light generating system having a housing and a light generating device,
• wherein the light generating device has an elongated support and a plurality of LED light sources, the plurality of LED light sources are supported by the elongated support, and the plurality of LED light sources are configured to generate light source light;
• wherein the housing is thermally conductive, the housing has a reflective inner surface with a staircase profile with n stairs in which n≥2, at least one of the n stairs has a parabolic shape, at least one of the n stairs is in a plane perpendicular to a lamp axis of the light generating system, each of the n stairs have a stair length L1, and the reflective inner surface is reflective for the light source light;
• wherein the light generating device is mounted on the staircase profile over at least part of the stair length L1 and configured in thermal contact with the housing;
• wherein the light generating device is configured in physical contact with the reflective inner surface, the housing has a thermally conductive material, the elongated support has a support length L2 in which 0.5≤L2/L1≤1, and the housing has a thermal conductivity selected from the range of ≥0.8 W/(m*K);
• and
• wherein the light generating device has an elongated LED filament, the LED filament has the plurality of LED light sources encapsulated by an encapsulant with a luminescent material therein.