| 摘要 |
PURPOSE:To allow the varying of the spot diameter of irradiation with a laser without changing the distance between the lesion of a patient and the front end of an optical fiber by forming a condensing optical system as a zoom optical system and varying the numerical aperture of the laser luminous flux at the time of making the laser luminous flux incident to a guiding optical system. CONSTITUTION:The incident light passes the optical fiber 10 while repeating reflection in the core thereof and emits at the aperture angle nearly equal to the numerical aperture of the laser luminous flux of the time when the light enters the optical fiber at the time of emission from an exit end. The light is, therefore, emitted with the small aperture angle if the light is made incident with the small numerical aperture. The light is emitted with the large aperture angle if the light is made incident at the large numerical aperture. The device is so constituted that the aperture angle of the laser beam 22 emitted from the optical fiber 10 can be changed by the zoom optical system 3. The distance between the front end 12 of the optical fiber 10 and the lesion 15 can then be taken large as shown by L if the aperture angle A1 of the incident laser luminous flux is made small when a small spot size is desired. The perfect treatment is thus executed. |
