Patent ID: 6751175
Filing Date: 2004-06-15
Classification: G11B

Abstract:
An aberration correcting device to be placed in an optical path extending from a light source of an optical pickup apparatus for irradiating an incident light beam onto an optical disk having a light-permeable layer, up to the optical disk, comprising:a receiving light-transmission plate having a first surface receiving a light beam from said light source and a second surface emitting said light beam, and said second surface having an aspherical curved shape; and an emitting light-transmission plate having a first surface receiving a light beam from said receiving light-transmission plate and a second surface emitting said light beam, being positioned apart from said receiving light-transmission plate along an optical axis of said optical path, and said first surface having a complementary aspherical curved surface to said second surface of said receiving light-transmission plate; wherein said aspherical curved surfaces have a shape to apply such a wavefront aberration that does not change the advancing direction of the light beam to said light beam passing through said aberration correcting device, and said receiving and emitting light-transmission plates are held freely movable relative to each other in a direction transverse to the optical path.