Patent ID: 7920444
Filing Date: 2011-04-05
Classification: G11B

Abstract:
1. An assembling method for an optical system of an optical pick-up including a semiconductor laser, a collimator lens and an objective lens, the method comprising: defining a maximum admissible astigmatism for the entire optical system; installing, on a rear side of the semiconductor laser, the collimator lens on a body case of the optical system to cause a predetermined amount of astigmatism lying within a range of up to the maximum admissible astigmatism for the entire optical system by tilting the collimator lens with respect to a center of the collimator lens from a condition where a point source of the semiconductor laser lies on an optical axis of the collimator lens; and installing, on a rear side of the collimator lens, the objective lens on the body case of the optical system to bring a total amount of astigmatism of the entire optical system to a level smaller than or equal to the maximum admissible astigmatism for the entire optical system by rotating the objective lens about an optical axis of the objective lens under a condition where the point source of the semiconductor laser and the center of the collimator lens lie on the optical axis of the objective lens.