Patent ID: 8054553

Claim:
A method of controlling the illumination angle onto a target, comprising: illuminating onto the target with light from at least two light sources of pre-selected wavelengths; wherein each point on the target is illuminated by light from the light sources with a respective maximal illumination angle relative to a main illumination axis extending from substantially the center of the at least two light sources to the target; selecting a dichroic filter that transmits light from the at least two light sources as a function of the angle of incidence upon the filter; and positioning the dichroic filter between the at least two light sources and the target to limit the transfer of light to light of the pre-selected wavelengths; wherein said dichroic filter is selected to limit the maximal illumination angle illuminating each point on the target; wherein said dichroic filter does not form a right angle relative to the main illumination axis; and wherein the angle of the dichroic filter is user controllable.