Annealing device and annealing method

An annealing apparatus adapted for annealing magnetic layers of a magneto optical recording medium,

• the annealing apparatus comprising:
• a light source for emitting light beams having a predetermined wavelength;
• diffraction optical means for optically separating light beams emitted from the light source into first light beams which are the 0 (zero)-th order diffracted light beams and second and third light beams which are the first order diffracted light beams, wherein in the case where each of beam outputs of the second and third light beams is caused to be a beam output necessary in annealing the magnetic layers, the diffraction optical means serves to adjust light quantity ratio between the first light beams and the second and third light beams so that a beam output of the first light beams is equal to the beam output necessary in performing anneal processing or less to optically separate the light beams thus obtained;
• irradiation means for converging the first light beams which have been optically separated at the diffraction optical means to irradiate the first light beams thus converged onto the magnetic layers of guide grooves or land portions forming both sides of the guide grooves which have been formed at the magneto optical recording medium, and for converging the second and third light beams to irradiate the second and third light beams which have been thus converged onto the magnetic layers in the vicinity of the boundary portions between the guide groove and the land portion;
• first intensity distribution detecting means for detecting intensity distribution of light quantities of rays of return light of the first light beams which have been irradiated onto the magnetic layers of the guide grooves;
• first tracking error signal generating means for generating a first tracking error signal on the basis of the intensity distribution of light quantities of rays of return light of the first light beams detected by the first intensity distribution detecting means;
• and
• control means for controlling the irradiation means on the basis of linear characteristic of the first tracking error signal generated by the first tracking error signal generating means in such a manner that the first light beams follow the guide grooves or the land portions.