Aberration-correcting method, laser processing method using said aberration-correcting method, laser irradiation method using said aberration-correcting method, aberration-correcting device and aberration-correcting program

A laser processing method for a laser processing device including a light source for generating a laser beam, a spatial light modulator for modulating the phase of a laser beam from the light source, and a condenser lens for focusing the laser beam from the spatial light modulator on a processing position inside a processing target, comprising:

• setting the processing position inside the processing target;
• setting a relative movement distance of the processing target so that the processing position is positioned within a range in which longitudinal aberration is present inside the processing target when the aberration is not corrected;
• calculating a correction wavefront so that the laser beam is focused on the processing position, and displaying the correction wavefront on the spatial light modulator;
• relatively moving the focal position so that the distance between the processing target and the condenser lens becomes the relative movement distance;
• and
• irradiating the laser beam from the light source onto the processing position in the processing target.

A laser irradiation method for a laser irradiation device including a light source for generating a laser beam, a spatial light modulator for modulating the phase of a laser beam from the light source, and a condenser lens for focusing the laser beam from the spatial light modulator on a predetermined focal position inside a medium, comprising:

• setting the focal position inside the medium;
• setting a relative movement distance of the medium so that the focal position is positioned within a range in which longitudinal aberration is present inside the medium when the aberration is not corrected;
• calculating a correction wavefront so that the laser beam is focused on the focal position, and displaying the correction wavefront on the spatial light modulator;
• relatively moving the focal position so that the distance between the medium and the condenser lens becomes the relative movement distance;
• and
• irradiating the laser beam from the light source onto the focal position in the medium.

An aberration-correcting method for a laser irradiation device which focuses a laser beam on the inside of a transparent medium, comprising:

• a first correction wavefront generation step for obtaining a plurality of correction wavefronts which are for correcting aberration of a laser beam so that a focal point of the laser beam is positioned within a range in which longitudinal aberration is present inside a medium when the aberration is not corrected, and correspond to a plurality of processing positions inside the medium, and a plurality of distances, which are correspond to the plurality of processing positions inside the medium, from a medium surface to the positions of the focal points when the medium is absent;
• a first polynomial approximation step for obtaining a first high-order polynomial by performing high-order polynomial approximation of the plurality of distances from the medium surface to the positions of the focal points when the medium is absent;
• a second polynomial approximation step for obtaining a plurality of second high-order polynomials by performing high-order polynomial approximation of the plurality of correction wavefronts;
• a third polynomial approximation step for obtaining a plurality of third high-order polynomials including the processing positions as parameters by performing high-order polynomial approximation of a plurality of coefficient sequences consisting of coefficients of the same order terms in the plurality of second high-order polynomials;
• a storing step for storing coefficients of a plurality of order terms in the first high-order polynomial and coefficients of a plurality of order terms in the plurality of third high-order polynomials;
• and
• a second correction wavefront generation step for obtaining a correction wavefront of an arbitrary processing position by using a second high-order polynomial by obtaining the second high-order polynomial of the arbitrary processing position equivalent to the plurality of second high-order polynomials by using coefficients of a plurality of order terms in the first high-order polynomial, the first high-order polynomial, coefficients of a plurality of order terms in the plurality of third high-order polynomials, and the plurality of third high-order polynomials.

An aberration-correcting device for a laser irradiation device which focuses a laser beam on the inside of a transparent medium, comprising:

• a first correction wavefront generation means for obtaining a plurality of correction wavefronts which are for correcting aberration of the laser beam so that a focal point of the laser beam is positioned within a range in which longitudinal aberration is present inside the medium when the aberration is not corrected, and correspond to a plurality of processing positions inside the medium, and a plurality of distances, which are correspond to the plurality of processing positions inside the medium, from a medium surface to a positions of the focal points when the medium is absent;
• a first polynomial approximation means for obtaining a first high-order polynomial by performing high-order polynomial approximation of the plurality of distances from the medium surface to the positions of the focal points when the medium is absent;
• a second polynomial approximation means for obtaining a plurality of second high-order polynomials by performing high-order polynomial approximation of the plurality of correction wavefronts;
• a third polynomial approximation means for obtaining a plurality of third high-order polynomials including the processing positions as parameters by performing high-order polynomial approximation of a plurality of coefficient sequences consisting of coefficients of the same order terms in the plurality of second high-order polynomials;
• a storing means for storing coefficients of a plurality of order terms in the first high-order polynomial and coefficients of a plurality of order terms in the plurality of third high-order polynomials;
• and
• a second correction wavefront generation means for obtaining a correction wavefront of an arbitrary processing position by using a second high-order polynomial by obtaining the second high-order polynomial of the arbitrary processing position equivalent to the plurality of second high-order polynomials by using coefficients of a plurality of order terms in the first high-order polynomial, the first high-order polynomial, coefficients of a plurality of order terms in the plurality of third high-order polynomials, and the plurality of third high-order polynomials.

A non-transitory computer readable storage medium storing an aberration-correcting program for a laser irradiation device which focuses a laser beam on the inside of a transparent medium, making a computer function as:

• a first correction wavefront generation means for obtaining a plurality of correction wavefronts which are for correcting aberration of the laser beam so that a focal point of the laser beam is positioned within a range in which longitudinal aberration is present inside the medium when the aberration is not corrected, and correspond to a plurality of processing positions inside the medium, and a plurality of distances, which are correspond to the plurality of processing positions inside the medium, from a medium surface to a positions of the focal points when the medium is absent;
• a first polynomial approximation means for obtaining a first high-order polynomial by performing high-order polynomial approximation of the plurality of distances from the medium surface to the positions of the focal points when the medium is absent;
• a second polynomial approximation means for obtaining a plurality of second high-order polynomials by performing high-order polynomial approximation of the plurality of correction wavefronts;
• a third polynomial approximation means for obtaining a plurality of third high-order polynomials including the processing positions as parameters by performing high-order polynomial approximation of a plurality of coefficient sequences consisting of coefficients of the same order terms in the plurality of second high-order polynomials;
• a storing means for storing coefficients of a plurality of order terms in the first high-order polynomial and coefficients of a plurality of order terms in the plurality of third high-order polynomials;
• and
• a second correction wavefront generation means for obtaining a correction wavefront of an arbitrary processing position by using a second high-order polynomial by obtaining the second high-order polynomial of the arbitrary processing position equivalent to the plurality of second high-order polynomials by using coefficients of a plurality of order terms in the first high-order polynomial, the first high-order polynomial, coefficients of a plurality of order terms in the plurality of third high-order polynomials, and the plurality of third high-order polynomials.

An aberration-correcting method for a light irradiation device, which focuses irradiation light on the inside of a transparent medium, including a focusing means for focusing an irradiation light on the inside of a medium and a spatial light modulator for correcting aberration of an irradiation light, comprising:

• setting a focal position inside the medium;
• setting a relative movement distance of the medium so that a focal point of the irradiation light is positioned within a range in which longitudinal aberration is present inside the medium when the aberration is not corrected;
• calculating a correction wavefront so that the irradiation light is focused on the focal position, and displaying the correction wavefront on the spatial light modulator;
• relatively moving the focal position so that the distance between the medium and the focusing means becomes the relative movement distance;
• and
• irradiating the irradiation light onto the focal position in the medium.