Laser apparatus and laser machining apparatus using same

1 . A laser apparatus comprising:

a laser oscillator configured to omit laser light;

an optical path changing component disposed on an optical path of the laser light and configured to change the optical path of the laser light;

an actuator coupled to the optical path changing component and configured to displace the optical path changing component;

an optical axis deviation detector surrounding the optical path of the laser light and configured to detect an optical axis deviation of the laser light from an optical axis of the optical path; and

a controller configured to drive the actuator based on a detection result of the optical axis deviation detector to displace the optical path changing component and thereby correct the optical axis deviation of the laser light,

wherein the optical axis deviation detector includes:

an annular aperture; and

a plurality of photodetectors on a first surface of the aperture at predetermined intervals, the first surface facing a traveling direction of the laser light,

wherein an inner diameter of the annular aperture is larger than a diameter of an area through which a mode component of the laser light necessary for machining passes, and each of the plurality of photodetectors is disposed outside the area, and

wherein the optical axis deviation detector is configured to detect the optical axis deviation of the laser light by detecting magnitudes of output signals transmitted from the plurality of photodetectors, and by determining whether the magnitudes of the output signals indicate that the optical path of the laser light has approached one or more of the plurality of photodetectors of the optical axis deviation detector.

2 . The laser apparatus according to claim 1 , wherein the plurality of photodetectors includes a first photodetector and a second photodetector respectively provided at positions facing each other in a first direction in the first surface with an optical axis of the laser light interposed between the first photodetector and the second photodetector, and a third photodetector and a fourth photodetector respectively provided at positions facing each other in a second direction substantially orthogonal to the first direction with the optical axis of the laser light interposed between the third photodetector and the fourth photodetector.

3 . The laser apparatus according to claim 1 , wherein:

a deviation amount of the optical axis of the laser light and an output range of each of the plurality of photodetectors are associated in advance, and

the controller is configured to drive the actuator to displace the optical path changing component, and to keep the output range of each of the plurality of photodetectors within a predetermined allowable range.

4 . The laser apparatus according to claim 1 , wherein:

the laser oscillator includes at least a plurality of laser modules, a beam combiner configured to couple module laser beams respectively emitted from the plurality of laser modules and emit the coupled module laser beams as the laser light, and a condensing optical unit including a condensing lens configured to reduce the laser light emitted from the beam combiner at a predetermined magnification and condense the laser light, and

the optical path changing component is disposed in at least one of an inside of the beam combiner and an inside of the condensing optical unit.

5 . The laser apparatus according to claim 4 , wherein the optical axis deviation detector is disposed between a laser light incident port of the condensing optical unit and the condensing lens.

6 . The laser apparatus according to claim 4 , wherein:

the condensing optical unit is connected to a transmission fiber to transmit the laser light,

the transmission fiber has a mode stripper near a connection with the condensing optical unit, and

the optical axis deviation detector surrounds the mode stripper.

7 . The laser apparatus according to claim 1 , wherein:

the optical path changing component is one of a plurality of optical path changing components on the optical path of the laser light, and

the optical axis deviation detector is one of a plurality of optical axis deviation detectors arranged at predetermined intervals along the optical axis of the laser light according to a number of the plurality of the optical path changing components coupled to the actuator.

8 . The laser apparatus according to claim 7 , wherein each of the plurality of optical path changing components comprises at least one of:

a reflection mirror configured to reflect in a predetermined direction the laser light inputted,

a lens configured to shape the laser light inputted into a predetermined shape, and

a parallel flat plate having a refractive index larger than 1 with respect to the laser light and configured to transmit the laser light.

9 . The laser apparatus according to claim 1 , wherein the actuator is a piezoelectric actuator.

10 . A laser machining apparatus comprising:

the laser apparatus according to claim 1 ;

a transmission fiber configured to transmit the laser light emitted from the laser apparatus; and

a laser processing head attached to an emission end of the transmission fiber and configured to illuminate the laser light toward a workpiece.