Optical disk device and adjusting method therefor

Abstract

There provide an optical disk system where occurrence of crosstalk between error signals is prevented without adding a correction circuit in order to detect a focusing error signal by an astigmatism method, and to provide an adjusting method thereof. In the optical disk system, a sensor lens 47 used for generating the focusing error signal by the astigmatism method is rotated around an optical axis L to correct inclination of the spot of return light on an optical detector 3 caused by the aberration of the other optical elements.

Description

field of invention [0001] The present invention relates to an optical disc device for reproducing information recorded on an optical disc or / and recording information. Background technique [0002] Various schemes have been proposed as a structure for signal detection of an optical disc, but even in the case of adopting any of the structures, the optical disc device basically has: a laser light source, a photodetector, and a An optical system that guides emitted laser light to the outgoing path of the optical disc and guides the return light reflected by the optical disc to the incoming path of the photodetector. [0003] In such an optical disc device, based on a signal detected by a photodetector, information recorded on the optical disc is reproduced, and a focus error signal and a tracking error signal are simultaneously generated. In such signal detection, a push-pull method (Push-Pull) is often used as a method for detecting tracking errors. Also, if the push-pull me...

AI Technical Summary

Problems solved by technology

However, the aberration of optical components may fluctuate depending on the manufacturing lot number, etc. When the aberration of the optical components used in the optical system differs greatly from the estimated amount, as shown on the right side of the figure (c), the The direction of the light and dark pattern is skewed

Therefore, although the objective lens is at the in-focus position, as a focus error signal, for example, a positive value signal is generated, and as a result, the objective lens is read as being out of focus.

Such push-pull crosstalk to the focus error signal, known as focus error / tracking error crosstalk (crosstalk), creates problems that cause focus servo instability

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