PURPOSE: To reduce inertia, to accelerate a scanning speed, to widen a scanning range and to improve the accuracy of scanning by putting a convergence optical system in circulating motion and making a scan.
CONSTITUTION: A laser beam 9a emitted by a laser oscillator 9 passes through the convergence optical system 10 which is put in circulating motion and converged by an optical system which makes the beam incidence of the convergence optical system to illuminate a work 12. The convergence optical system 10 is in rotary motion, so its inertial becomes small and its scanning speed is made larger than that of a conventional mechanical means. Further, a wide scanning range is obtained as compared with a device which uses an expensive optical system such as a rotary polygon mirror and a galvanometer and a lens with short focal length is usable for the convergence optical system 10, so there is advantages such as reduction in converged spot diameter. A scanning track is a circulating track, so a countermeasure for preventing an unnecessary part from being irradiated with the laser beam 9a, i.e. to provide a mask is necessary.
MAKINO MASASHI
UESUGI YUJI
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