Radial tilt detector

Abstract

A radial tilt detector which is capable of detecting a tilt in a radial direction of an optical disc at a high degree of precision and being cost-effective and simple in head part. A radial tilt detector of an optical disc information recording / reproduction apparatus is used for detecting the radial tilt, which is the amount of radial inclination on the recording surface of the disc. The detector comprises a velocity detector responsive to the drive signal from the driver for detecting a velocity in a direction depending on an optical axis of the light heat at the position focused by the focus actuator, and a radial tilt calculation processor for calculating the radial tilt on the basis of the velocity detected by the velocity detector and the number of rotations of the optical disc.

Description

technical field [0001] The present invention generally relates to a tilt detector of an optical head tilt servo device in an optical disc player, and more particularly, to a radial tilt detector for detecting the tilt of an optical disc in the radial direction. Background technique [0002] An optical disc device generally projects a small and narrow light beam onto an optical disc through an objective lens, and scans fine marks (recording marks) on the disc, thereby reproducing information recorded thereon. At the same time, due to disc distortion, surface vibration, etc., the surface of the disc may be inclined relative to the beam from the optical head. In this case, when the light beam from the optical head is incident on the surface of the optical disc to reproduce the information recorded thereon, since the light beam is inclined relative to the surface of the optical disc, it is difficult to accurately read the recorded information. [0003] Figure 5 The variation o...

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Problems solved by technology

[0008] However, in the head of the above-mentioned structure, since the light spot and the tilt sensor cannot be precisely aligned with each other, errors will inevitably occur in the value detected by the tilt sensor.

Therefore, when high-precision tilt correction is required due to the demand for densification of optical disc recording, sufficient accuracy cannot be guaranteed

[0009] In addition, since the optical head and the tilt detection device are provided separately, the number of components increases, resulting in an increase in the cost and the complexity of the structure of the optical head components.

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