Illumination system for spot illumination

An illumination system for spot illumination comprising:

• a tubular reflector having a substantially polygonal cross-section with a reflective inner surface, said tubular reflector having an entrance aperture and an exit aperture being larger than the entrance aperture;
• a light-source array comprising a plurality of light-sources arranged to emit light into the tubular reflector at the entrance aperture thereof;
• and
• a light-diffusing optical member arranged to diffuse light emitted by said illumination system,
• wherein said light-diffusing member is configured to exhibit an increasing diffusing capability with increasing distance from an optical axis of the illumination system,
• wherein at least one of said tubular reflector and said light-source array is configured in such a way that each ordinary non-bisecting symmetry state of said light-source array is different from an ordinary symmetry state of said tubular reflector.