Luminaire with light exit window

A luminaire, comprising

• at least one light source arranged to emit light source light,
• a light exit window, wherein the emitted light source light is arranged to exit the luminaire through the light exit window as luminaire light,
• wherein the light exit window is configured to influence or modify the luminance, L, of the light source light, for generating a profile of the luminance, LP, of the luminaire light as a function of a length dimension, x, of the light exit window, defined from a center of the light exit window to a periphery of the light exit window, wherein the profile of the luminance, LP, at least comprises
• a first interval, x1, of the length dimension, x, comprising a step function, S(x), of the luminance, LP, with a first gradient, G1=dLP/dx,
• a second interval, x2, of the length dimension, x, adjacently arranged the first interval, x1, wherein the second interval, x2, comprises a function, F(x), of the luminance, LP, with a second gradient, G2=dLP/dx, and
• a third interval, x3, of the length dimension, x, adjacently arranged one of the first interval, x1, and the second interval, x2, comprising a nominal level, Ln(x), of the luminance, LP, with a third gradient, G3=dLP/dx,
• wherein one of
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• is fulfilled,
• and wherein the profile of the luminance LP in the direction from its center of the light exit window to the periphery of the light exit window comprises a change in luminance, L, from a first luminance, L1, via the step function, S(x), in luminance comprising at least one of a maximum step luminance Lsmax, and a minimum step luminance Lsmin, to a second luminance, L2, wherein L1, L2>Lsmin and L1, L2<Lsmax.