| 摘要 |
<p>A laser beam delivery system has an improved focus adjustment for controlling the depth at which the beam focusses in the target. An objective lens (24) remains stationary with respect to the target (26), and focus depth is controlled by adjusting the separation between a pair of positive and negative lenses (46, 48) which are positioned a distance behind the objective lens at least one additional optical path (34) is folded onto the laser beam path upstream of the objective lens. Thus, the surgical laser axis and at least one further axis on which analysis, target imaging and other functions are performed are joined together upstream of the objective lens. In this way, the laser beam may be focussed to given depth in the target, without interrupting optics along the partially colinear axis. Also, the objective lens assembly, which may be quite massive, is not relied upon for quick-response focussing during a surgical procedure.</p> |
