Information disc recording/playback apparatus, and vibration detection method for information disc recording/playback apparatus

Abstract

The present invention provides an information disc recording / playback apparatus which includes a track cross detection means (112), a track cross direction detection means (113), a rotation angle detection means (114), and a count means (115), detects the track pitch of a disc, evaluates the vibration amount, or vibration speed, or vibration acceleration considering the track pitch of the disc, and determines a maximum rotation speed that is lower than the allowable vibration amplitude, vibration speed, or vibration acceleration of the information disc recording / playback apparatus; as well as a vibration detection method for the information disc recording / playback apparatus. This information disc recording / playback apparatus can perform vibration detection using a single threshold value that is independent of the type of the disc, without using an acceleration sensor, and further, the apparatus can accurately perform vibration detection even when direction detection is difficult.

Description

[0001] This is a divisional of U.S. application Ser. No. 10 / 148,808, filed Jun. 5, 2002, which is a National Stage Application of International Application No. PCT / JP01 / 09934, filed Nov. 14, 2001.TECHNICAL FIELD [0002] The present invention relates to an information disc recording / playback apparatus having a vibration measurement means for measuring vibrations caused by an eccentricity of a disc, and a vibration detection method for the information disc recording / playback apparatus. More particularly, the invention relates to an information disc recording / playback apparatus having a construction for performing vibration detection using track counting. BACKGROUND ART [0003] In recent years, optical disc playback apparatuses have made a remarkable increase in the recording / playback speed. The optical disc playback apparatuses have achieved the increase in the playback speed by increasing the rotation speed of optical discs. [0004] However, when the rotation speed of an optical disc is...

AI Technical Summary

Benefits of technology

[0083] Furthermore, according to an information disc recording / playback apparatus and a vibration detection method for the information disc recording / playback apparatus relating to the present invention, there is provided an information disc recording / playback apparatus capable of recording or playing an information disc on which information recording tracks are formed spirally or concentrically, which apparatus comprises: a disc rotation means for rotating the information disc at a predetermined speed; a reading means for reading an information signal from the disc; a drive means for driving the reading means in the direction of the radius of the disc; a track cross detection means for generating track cross pulses on the basis of playback signals that are generated when the reading means crosses the information tracks; a variable filter means for preventing counting of pulses whose widths are narrower than a set value, among the track cross pulses; a count means for counting the pulses outputted from the variable filter means; and a control means for determining a maximum rotation speed that is lower than an allowable number of track crosses of the information disc recording / playback apparatus on the basis of the count, or determining a maximum rotation speed that is lower than an allowable track cross speed or track cross acceleration of the information disc recording / playback apparatus on the basis of the count and the current disc rotation speed, and controlling the disc rotation means so that the disc rotation means rotates the information disc at a speed lower than the allowable maximum rotation speed to record or reproduce data in / from the disc. Since setting of the track cross filter is carried out on the basis of the track cross count and the current rotation speed, even when the track cross speed varies significantly due to the eccentricity or vibration of the disc, track counting most suitable for vibration detection can be accurately carried out at all times.

[0084] Furthermore, according to an information disc recording / playback apparatus relating to the present invention, there is provided an information disc recording / playback apparatus capable of recording or playing an information disc on which information recording tracks are formed spirally or concentrically, which apparatus comprises: a disc rotation means for rotating the information disc at a predetermined speed; a reading means for reading an information signal from the disc; a drive means for driving the reading means in the direction of the radius of the disc; a track cross detection means for generating track cross signals on the basis of playback signals that are generated when the reading means crosses the information tracks; a pulse width storage means for holding the pulse width of a just-previous track cross signal; a filter means for comparing the pulse width of the just-previous track cross signal with the pulse width of the current track cross signal, and preventing the current track cross signal from being outputted when the current track cross signal is reduced by a predetermined value or more; a count means for counting the pulses which are outputted from the variable filter means; and a control means for determining a maximum rotation speed that is lower than an allowable number of track crosses of the information disc recording / playback apparatus on the basis of the obtained counts for one or more rotation, or determining a maximum rotation speed that is lower than an allowable track cross speed or track cross acceleration of the information disc recording / playback apparatus on the basis of the obtained counts for one or more rotation, and the current disc rotation speed, and controlling the disc rotation means so that the disc rotation means rotates the information disc at a speed lower than the allowable maximum rotation speed to record or reproduce data in / from the disc. Therefore, when the current pulse width is smaller than the previous pulse width by a predetermined value, this pulse is judged as one caused by false detection due to noise and is not counted, whereby track counting most suitable for vibration detection can be accurately carried out at all times, without requiring time for excess measurement.

Problems solved by technology

However, when the rotation speed of an optical disc is increased, vibration due to an eccentricity of the optical disc adversely affects control such as servo, resulting in a problem that the user of the optical disc playback apparatus might feel uncomfortable.

However, an increase in cost due to mounting of the acceleration sensor 805 and a signal amplifier for amplifying the signal from the acceleration sensor 805 is considerable.

However, the vibration of the disc device varies depending on the setting condition of the disc device on a system, and moreover, the vibration amplitude with which the user feels uncomfortable depends on the human sense and so it varies depending on the user.

However, since threshold setting varies depending on the loading condition or the like of the disc to be used on the disc device, a large amount of data must be measured, and the amount of data further increases according to the number of disc types, whereby enormous time is required.

However, in the case where the frequency and the speed change in the frequency are changed considerably due to the eccentricity of the disc or the vibration amplitude like the track count pulses for vibration detection, it is difficult to set the response speed to the change in the filter characteristics, resulting in false count when the response speed is too high or too low.

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