Beam track position control apparatus for optical disk apparatus

Claim 2

A beam track position control apparatus for an optical disk apparatus including a rotatable optical disk on which means for guiding a beam spot projected thereon are formed an optical head including light source means for emitting first and second beams of light and means for focusing the first and the second beams onto the optical disk, and track actuator means for moving the focusing means in the radial direction, said beam track position control apparatus comprising: first photodetector means for detecting light of the first beam reflected from said optical disk and producing a first output signal; second photodetector means for detecting light of the second beam reflected from said optical disk and producing a second output signal; first control means for controlling said track actuator means based on a track error signal obtained from the first output signal from said first photodetector means; and second control means for controlling the position of a beam spot of said second beam on said optical disk based on another track error signal obtained from the second output signal from said second photodetector means.

Claim 3

A beam track position control apparatus for an optical disk apparatus including a rotatable optical disk on which means for guiding a beam spot projected thereon are formed, an optical head including a light source means for emitting first and second beams of light and means for focusing the first and the second beams onto the optical disk, and track actuator means for moving the focusing means in the radial direction, said beam track position control apparatus comprising: first photodetector means for detecting light of the first beam reflected from said optical disk and producing a first output signal; second photodetector means for detecting light of the second beam reflected from said optical disk and producing a second output signal; means for inclining the optical axis of the second beam passing through said focusing means and changing the position of the second beam incident on said optical disk; actuator means for driving said optical axis inclining means; third photodetector means for detecting a current position of said optical axis inclining means and producing a third output signal; first control means for controlling said track actuator means based on a track error signal obtained from the first output signal from said first photodetector means; and second control means for controlling said actuator means based on another track error signal obtained from the second output signal from said second photodetector means and a current position signal obtained from the third output signal from said third photodetector means to thereby change the position of the second beam incident on said optical disk.

Claim 4

A beam track position control apparatus for an optical disk apparatus including a rotatable optical disk on which means for guiding a beam spot projected thereon are formed, an optical head including a light source means for emitting first and second beams of light and means for focusing the first and the second beams onto the optical disk, and track actuator means for moving the focusing means in the radial direction, said beam track position control apparatus comprising: first photodetector means for detecting light of the first beam reflected from said optical disk and producing a first output signal; second photodetector means for detecting light of the second beam reflected from said optical disk and producing a second output signal; means for inclining the optical axis of the second beam passing through said focusing means and changing the position of the second beam incident on said optical disk; actuator means for driving said optical axis inclining means; third photodetector means for detecting a current position of said optical axis inclining means and producing a third output signal; first control means for controlling said track actuator means based on a track error signal obtained from the first output signal from said first photodetector means; and second control means for controlling said actuator means based on another track error signal obtained from the second output signal from said second photodetector means and a current position signal obtained from the third output signal from said third photodetector means to thereby change the position of the second beam incident on said optical disk.

Claim 5

A beam track position control apparatus according to claim 2, wherein said optical axis inclining means is a mirror pivotally mounted about a pivot axis.

Claim 6

A beam track position control apparatus according to claim 1,2 or 3, wherein said first beam is a write beam and said second beam is a read beam.

Claim 7

A beam track position control apparatus according to claim 2,3 or 4, wherein said first photodetector means comprises a four-division photo­detector and said second and third photodetectors each comprises a two-division photodetector.

Claim 8

A beam track position control apparatus as claimed in any preceding claim, for an optical disk apparatus in which said means for guiding a beam spot comprises a plurality of guide grooves spirally formed along a direction of rotation of the optical disk, in which said light source means comprises respective first and second light sources for the first and second beams of light, and in which said focusing means for focusing the first and second beams comprises an object lens.

Claim 9

A beam track position control method for an optical disk apparatus including a rotatable optical disk on which means for guiding a beam spot projected thereon are formed, and means for focusing light beams onto the optical disk, comprising the steps of: projecting first and second beams onto said optical disk simultaneously through said focusing means ; obtaining a first signal by detecting light of said first beam reflected from said optical disk; producing a track error signal from said first signal; controlling the movements of beam spots of said first and second beams on said optical disk based on said track error signal; obtaining a second signal by detecting light of said second beam reflected from said optical disk; producing another track error signal from said second signal; and controlling the movement of the beam spot of said second beam on said optical disk based on said another track error signal.

Claim 10

A beam track position control method for an optical disk apparatus including a rotatable optical disk on which means for guiding a beam spot projected thereon are formed, and means for focusing light beams onto the optical disk, comprising the steps of: projecting first and second beams onto said optical disk simultaneously through said focusing means ; obtaining a first signal by detecting light of said first beam reflected from said optical disk; producing a track error signal from said first signal; controlling the movements of beam spots of said first and second beams on said optical disk based on said track error signal; obtaining a second signal by detecting light of said second beam reflected from said optical disk; producing another track error signal from said second signal; and controlling the movement of the beam spot of said second beam on said optical disk based on said another track error signal.

Claim 11

A beam track position control method according to claim 7, wherein said means on the optical disk for guiding a beam spot comprise a plurality of guide grooves spirally formed along a direction of rotation of the optical disk, and wherein said focusing means comprises an object lens.