Device for altering material structure using pulsed light beam - coagulation o biological tissues is produced in spatially limited region by using pulsing laser light beam with pref. light strength

摘要

In a system for treating materials with a light beam, a time or spatial switching (3,4 or 5) of the light source (1) produces a repeated pulsing of the light beam (2) to limit the area of structural change in the subject material to the structure which directly absorbs the light and the material immediately surrounding it. This may be obtd by moving the light beam (2) over the material surface so each part of the surface is repeatedly exposed to the light. The subject material for the process is biological tissue. The light source (1) may take the form of a laser whose beam is controlled by an external switching device, by a switching device in the laser resonator, or by a switching device in the pumping system of the laser. The light pulsing may be dosed so obtd material changes are of a simple thermal nature - ie only temp changes in the light-absorbing structure and the immediately surrounding material are produced, or so changes are of an acoustical-mechanical- or a photochemical-nature. USE/ADVANTAGE - Used in the treatment of material, and esp thermal alteration - ie coagulation - of biological tissues, by a light beam, where it is required to treat limited part of it. The system described provides a high deg of spatial selectivity in the material alteration produced.