| 摘要 |
FIELD: physics.SUBSTANCE: illumination device has a plurality of light sources which provide light at different wavelengths and a collimating means. The collimating means has a receiving end and an output end, wherein light sources are placed at the receiving end. The collimating means has a first set of wavelength-selective filters in form of sub-collimators for each of the plurality of light sources. For each light source, a sub-collimator collimates light from its light source. The wavelength-selective filter of each light source is transparent for light from neighbouring light sources at different wavelengths. The collimating means has a second set of wavelength-selective filters, having compensating filters. The compensating filters are arranged symmetrically about the corresponding portion of the wavelength-selective filter of the first set around the general direction of light of the corresponding light source. The compensating filters are designed to compensate for decolouration caused by asymmetry of the collimating means.EFFECT: reduced decolouration.17 cl, 7 dwg |
