Patent ID: 6125088
Filing Date: 2000-09-26
Classification: G02F,G11B

Abstract:
An aberration correcting apparatus for correcting an aberration of a laser beam that is emitted from a light source and focused onto an information recording medium by an optical system, the aberration correcting apparatus comprising:detecting means for detecting a radial tilt-angle and a tangential tilt-angle of an information recording medium;wave front aberration correcting means, aligned in an optical path between the light source and the information recording medium, the wave front aberration correcting means including a first layer and a second layer for correcting a wave front aberration of an incident laser beam by changing a refractive index of a first material in the first layer according to a first applied voltage corresponding to the radial tilt-angle, and by changing a refractive index of a second material in the second layer according to a second applied voltage corresponding to the tangential tilt-angle; andcontrol means for controlling the wave front aberration correcting means in correspondence with an output of the detecting means.