Patent ID: 8175841

Claim:
A method for controlling an illumination system comprising a plurality of coloured light sources, there being at least one or more light sources of a first colour and one or more light sources of a second colour, the first colour being different from the second colour, the illumination system being for emitting illumination light, the method comprising determining first drive settings for each of the plurality of coloured light sources so as to provide illumination light with a pre-determined colour point and/or a pre-determined luminance, the first drive settings generating an ON time and an OFF time of the light sources; for each of the light sources of the first colour and the light sources of the second colour performing a measuring step, the measuring step comprising changing the first drive settings so that the ON time of the light sources of a selected one of the first and second colour does not coincide with the ON time of the light sources of the other colours for at least a period of time, and during that period of time, measuring the peak luminance of the light sources of the selected one of the first and second colour; and for each of the light sources of the first colour and the second colour performing a calculation step, comprising based on the measured peak luminance for the light sources of that colour, and recalculating the drive settings into second drive settings so as to maintain pre-determined colour point.