Patent ID: 7733759
Filing Date: 2010-06-08
Classification: G11B

Abstract:
1. An optical pickup comprising: a laser light source for irradiating an optical disc with a light beam; an objective lens for focusing the light beam emitted from the laser light source on the optical disc; a first lens for correcting astigmatism; a second lens for correcting coma aberration; and a photodetector for receiving the light beam reflected from the optical disc; wherein the astigmatism and the coma aberration are corrected independently of each other by using the first lens or the second lens, wherein at least one of: a Root Mean Square (RMS) value of the astigmatism that occurs when the first lens is moved in a direction perpendicular to an optical axis is greater than an RMS value of the coma aberration, and the RMS value of the coma aberration that occurs when the second lens is moved in a direction perpendicular to the optical axis is greater than the RMS value of the astigmatism.