LIGHT MODULATION CONTROL METHOD, CONTROL PROGRAM, CONTROL DEVICE AND LASER BEAM IRRADIATION DEVICE

摘要

In the control of light condensing irradiation of laser light using a spatial light modulator, the number of wavelengths, a value of each wavelength, and incident conditions of the laser light are acquired, the number of light condensing points, and a light condensing position, a wavelength, and a light condensing intensity on each light condensing point are set, and a light condensing control pattern is set for each light condensing point. Then, a modulation pattern presented in the spatial light modulator is designed in consideration of the light condensing control pattern. Further, in the design of a modulation pattern, a design method focusing on an effect by a phase value of one pixel is used, and when evaluating a light condensing state, a propagation function to which a phase pattern opposite to the light condensing control pattern is added is used.

主权项

1. A light modulation control method which controls light condensing irradiation of laser light onto a set light condensing point by a modulation pattern to be presented in a spatial light modulator by use of the phase-modulation type spatial light modulator that inputs the laser light thereto, to modulate a phase of the laser light, and that outputs the phase-modulated laser light, the method comprising:
an irradiation condition acquiring step of acquiring the number of wavelengths xt (xt is an integer of 1 or more) of the laser light to be input to the spatial light modulator, xt wavelengths λx, and incident conditions of the laser light at each wavelength to the spatial light modulator, as irradiation conditions of the laser light; a light condensing condition setting step of setting the number of the light condensing points st (st is an integer of 1 or more) on which light condensing irradiation of the laser light from the spatial light modulator is performed, and a light condensing position, a wavelength λx of the laser light to be condensed, and a light condensing intensity for each of the st light condensing points s, as light condensing conditions of the laser light; a control pattern setting step of setting a light condensing control pattern for controlling a light condensing state as a phase pattern to be provided for the laser light at the wavelength λx for each of the st light condensing points s; and a modulation pattern designing step of designing the modulation pattern to be presented in the spatial light modulator in consideration of the light condensing control pattern set in the control pattern setting step, the method wherein the modulation pattern designing step assumes a plurality of two-dimensionally arrayed pixels in the spatial light modulator, changes a phase value so as to bring a light condensing state closer to a desired state by focusing on an effect on the light condensing state of the laser light on the light condensing point by changing the phase value of one pixel in the modulation pattern to be presented in the plurality of pixels, and performs such phase value changing operations for all the pixels in the modulation pattern, thereby designing the modulation pattern, and when evaluating the light condensing state on the light condensing point, a propagation function φjs,x′
φjs,x′=φjs,x−φjs-pat,x that is, a phase pattern opposite to the light condensing control pattern φjs-pat,x which is set in the control pattern setting step is added to a wave propagation function φjs,x is used, for propagation of light at a wavelength λx from a pixel j in the modulation pattern of the spatial light modulator to the light condensing point s.