US Patent 9119668 Surgical lamps and methods for illuminating operating sites

A surgical lamp for illuminating an operating site includes a lamp body that includes first and second light sources that respectively generate first and second light fields of different diameter on the operating site. When a change in a distance between the lamp body and the operating site is detected, the first and second light intensities of the first and second light sources, respectively, can be controlled such that the predetermined diameter (dx) at which the preset relative central illuminance (Ecx) of the resultant light field is generated is maintained at a substantially constant value as the distance changes.