| 摘要 |
PURPOSE:To obtain a uniform state of initial crystallization over the whole recording layer by irradiating the information recording medium with a beam for initial crystallization in a manner that the irradiation power of the beam differs for the outer circumferential area and for the center area of the medium. CONSTITUTION:Laser light from a semiconductor laser source 13 is changed into a parallel beam by a collimator lens 14, directed to enter an objective lens 16 by a beam splitter 15, and focused on a recording layer of a disk substrate 10. A position detector 17 detects the position of the optical unit 12 and sends signals according to the detected position to a controller 18. The controller 18 controls output of the semiconductor laser source 3 according to the input signal from the detector, for example, the output of the laser light gradually increases from the center part of the disk substrate to the outer circumference. By this method, the recording layer of the disk substrate can be uniformly irradiated with the beam in a constant energy density. Thus, the whole recording layer can be initially crystallized at the same level. |
