US 5,402,402 A · Apparatus for controlling a optical disk drive

Abstract

An optical disk drive apparatus operable under track following mode and seek mode wherein, upon the detection of a track following operation error, a seek operation is initiated for seeking a new target track at a predetermined number of tracks distant from the current track. The seek operation is controlled to follow a velocity profile thus regaining control over an optical head that may have been jolted into an out of control velocity when the track following error occurred. The velocity profile provides for a reduced velocity as the target track is approached. The new target track is selected at a relatively large number of tracks distant from the current track if the head velocity is high and at a relatively small number of current tracks if the head velocity is low. If the current track is sensed to be an outer track, the new target track is selected toward the inner track and if the current track is sensed to be an inner track, the new target track is selected to be an outer track.

Claims14

Dependent claims

An optical disk drive apparatus comprising:

an optical head for projecting a laser beam onto an optical disk;
coarse actuator means connected to said optical head for moving said optical head to a target track during a track seeking operation;
fine actuator means connected to said optical head for moving said optical head to keep said head accurately positioned on said target track during a track following operation;
tracking error detection means connected to said fine actuator means for detecting the failure of the track following operation, said tracking error detection means comprising means for generating a tracking error signal (TES) and means, coupled to receive the tracking error signal, for comparing an amplitude of the TES with a range of acceptable amplitudes and generating a TES error signal if the TES amplitude is outside of the range of acceptable amplitudes, the TES error signal indicative of the failure of the track following operation;
and
processor means, connected to control said optical head, said coarse actuator means, said fine actuator means and said tracking error means and responsive to the detection of the failure of the track following operation, for initiating a new seek operation to a new target track at a predetermined distance from a current track in order to recover from the failure.

3 more elements

An optical disk drive apparatus having an optical head for projecting a laser beam onto an optical disk comprising:

seek control means for performing a seek operation to move the beam from a current track to a target track under the control of seek velocity according to information in a velocity profile;
tracking control means for making the beam follow a track;
tracking error signal generating means for generating a tracking error signal indicating a deflection of said beam from a track center;
and
tracking error detection means for comparing the amplitude of the tracking error signal with a predetermined amplitude and generating a track following error signal when the amplitude of the tracking error signal or a signal derived therefrom exceeds the predetermined amplitude, the track following error signal indicative of a failure of the track following;
and
said seek control means comprising means for initiating a new seek operation to a predetermined distant track in response to the track following error signal.

4 more elements

Dependencies are inferred from the claim text.

Apparatus for controlling a optical disk drive

Life of this patent

Apparatus for controlling a optical disk drive

Life of this patent

Abstract

Claims14