Varifocal laser processing system and method based on variable light spot diffractive element

A varifocal laser processing method based on a variable light spot diffractive element, comprising the following steps:

• S1:
• selecting a laser device for generating a laser, a collimating lens for changing a light path and a diffractive optical element module for controlling light spot focal point distribution, arranging the collimating lens between the laser device and the diffractive optical element module, and selecting different characteristic functions according to lens array sizes, image element sizes and varifocal intervals of the DOE lenses to set a lens outline function of DOE lenses;
• S2:
• selecting, by the diffractive optical element module, at least two DOE lenses oppositely distributed in an axial direction and a rotary actuator driving the DOE lenses to rotate, and driving, by the rotary actuator, at least one DOE lens to rotate by an angle θ with an optical axis of the DOE lens as a rotating center, thereby enabling the at least two DOE lenses to mutually rotate so as to change optical power of the DOE lenses, and a position of a focal point generated after the laser is focused by the diffractive optical element module;
• and
• S3:
• starting the laser device, enabling, by the collimating lens, the laser emitted by the laser device to irradiate the diffractive optical element module, enabling the laser focused by the diffractive optical element module to irradiate a to-be-processed workpiece, and controlling, by the diffractive optical element module, the optical power of the DOE lenses and focal point distribution of the laser so that a focal point generated by the diffractive optical element module can move along a preset processing track so as to finish processing of the to-be-processed workpiece,
• wherein, step S2 further comprises a step of dynamic evaluation of transverse stagger deviation of the DOE lenses:
• arranging a transverse actuator, and driving, by the transverse actuator, at least one DOE lens to move in a radial direction perpendicular to the central axis so that the two DOE lenses can transversely move in a stagger manner, thereby measuring an influence degree of transverse stagger deviation of the two DOE lenses on the focal point position, wherein the two DOE lenses transversely move in a stagger manner with the precision being 0.1-1 micron.