Patent ID: 7270431

Claim:
An illumination device for use in a laser scanning microscope to provide a profiled illumination beam that is essentially homogeneous in at least one cross-sectional direction, the illuminating device comprising: means for transmitting an original beam which is inhomogeneous in cross-section and which has a point of incidence, and a mirror for expanding the original beam, the mirror being more strongly curved in the area of the point of incidence of the original beam than in the areas removed from the point of incidence to provide a profiled illumination beam that is essentially homogeneous in at least one cross-sectional direction, wherein the surface of the mirror has a top and the surface satisfies in Cartesian (x, y, z)-coordinates y 2 /[c+(c 2 −(1+Q)y 2 ) 1/2 ], where c is a radius of curvature of the top and Q is the conical constant, and wherein the mirror satisfies the equation f(x,y)=√{square root over ((a(y)−r x ) 2 −x 2 )}−r x , where r x is the radius of curvature along the longitudinal axis of the top and a(y) is the function of y 2 /[c+(c 2 −(1+Q)y 2 ) 1/2 ].