Patent ID: 8388174

Claim:
Lighting arrangement for illuminating an area under mesopic conditions comprising: one or more LEDs emitting substantially monochromatic light in a first wavelength region; one or more LEDs emitting substantially monochromatic light in a second wavelength region; such that, in use, the light provided by the lighting arrangement has an S/P-ratio greater than 2, wherein the S/P-ratio refers to the ratio between scotopic efficacy V′(λ) and photopic efficacy V(λ), and wherein emitted light in the first wavelength region in combination with emitted light in the second wavelength region results in light with chromaticity x-coordinates in the CIE 1931 color space chromaticity diagram between 0.290 and 0.330, and with chromaticity y-coordinates in the CIE 1931 color space chromaticity diagram between 0.550 and 0.590.