Optical disk device

Details Optical disk device Optical disk device

2002-09-25

2003-11-04

Hindi, Nabil (Department: 2655)

Dynamic information storage or retrieval

Control of storage or retrieval operation by a control...

Control of information signal processing channel

C369S047220

Reexamination Certificate

active

06643234

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to a disk format on optical disk, and to an optical disk device that can conduct the recording and playback of such an optical disk.
BACKGROUND OF THE INVENTION
In recent years, for a rewritable optical disk with a large capacity, a land/groove recording system that a region between grooves is also used as an information track, as well as a groove provided as a guide trench on optical disk is suggested. The land and groove may be called convex part and concave part, respectively, or called inter-groove part and groove part, respectively. First, an optical disk used in the conventional land/groove recording system is explained.
FIG. 1
is a partial enlarged plan view showing a conventional optical disk that is described in Japanese patent No. 2,663,817. In
FIG. 1
, G indicates a groove region, L indicates a land region, Tp indicates a track pitch, P indicates a pre-pit, and BS indicates a focused beam spot. Also, “identification signal region” in Japanese patent No. 2,663,817 is called “header region” herein. In this disk format, a header region including address information is shared between adjacent groove G and land L, and at least a part of information signal included in header region is shifted by Tp/4 to the center line of groove G and to the center line of land L, and in at least part of optical disk, the header region and recording data region each are formed in a radial pattern.
FIG. 2
is a block diagram showing the composition of an optical disk device used for the optical disk above. In
FIG. 2
,
100
is the optical disk,
103
is a half mirror serving as a beam splitter,
104
is an objective lens to converge collimated light passed through the half mirror
103
onto the optical disk
100
,
105
is a collimator lens to collimate light from a semiconductor laser
106
, and
108
is an optical detector to receive reflected light from the optical disk
100
passing though the objective lens
104
and the half mirror
103
. The optical detector is composed of two light-receiving parts that are divided in parallel to the track direction (tangential direction of circumference) of the optical disk to obtain the tracking error signal.
102
is an actuator supporting the objective lens
104
. Meanwhile, part
101
enclosed by a dotted line in
FIG. 2
is attached to a head base (not shown), and compose an optical head.
On the other hand,
110
is a differential amplifier to which detection signal to be output from the optical detector
108
is input.
117
is a polarity inverter to which tracking error signal from the differential amplifier
110
and control signal L
4
from a system controller
118
described later are input, and which controls the polarity of tracking error signal output to a tracking controller
116
according to the control signal L
4
. Hereupon, regarding the polarity of tracking control, when tracking error signal is input, with its polarity unaltered, from the differential amplifier
110
to the tracking controller
116
, the tracking is pulled into the recording track of groove G.
116
is the tracking controller to which output signal from the polarity inverter
117
and control signal L
1
from the system controller
118
are input, and which outputs tracking control signal to a driver
122
and a traverse controller
121
.
109
is an adder amplifier to which detection signal output from the optical detector
108
is input and which outputs add signal.
112
is a waveform shaper to which a RF component from the adder amplifier is input, and which outputs digital signal to a playback signal processor
113
and a address playback circuit
114
.
113
is the playback signal processor which outputs playback data to the output terminal.
114
is the address playback circuit to which digital signal from the waveform shaper
112
is input, and which outputs address signal.
115
is an address calculator to which address signal from the address playback circuit
114
and control signal L
4
from the system controller
118
are input, and which outputs address signal to the system controller
118
.
Also,
121
is the traverse controller which outputs drive current according to control signal from the system controller
118
.
107
is a traverse motor which moves the optical head
101
in the radius direction of the optical disk
100
according to drive current from the traverse controller
121
.
119
is a record signal processor to which record data is input and which outputs record signal to a laser (LD) driver
120
.
120
is the LD driver to which control signal from the system controller
118
and record signal from the record signal processor
119
are input, and which supplies drive current to the semiconductor laser
106
.
122
is the driver to which tracking control signal from the tracking controller
116
is input and which supplies drive current to the actuator
102
. Meanwhile, the system controller
118
which outputs control signal L
1
, L
4
to the tracking controller
116
, the traverse controller
121
, the address calculator
115
, the polarity inverter
117
, the record signal processor
119
and the LD driver
120
, and to which address signal from the address calculator
115
is input.
The operation of the conventional optical disk device thus composed is explained below.
Light output from the semiconductor laser
106
is collimated by the collimator lens
105
, passed through the beam splitter
103
, converged onto the optical disk
100
by the objective lens
104
. Laser light reflected on the optical disk
100
holds the information of record track, passing through the objective lens
104
, being led through the beam splitter
103
to the optical detector
108
. The optical detector
108
converts a variation in light quantity distribution of light beam supplied into electrical signal, outputting it to the differential amplifier
110
, the adder amplifier
109
. The differential amplifier
110
current-voltage-converts (I-V conversion) currents input, taking the difference of both voltages, outputting it as push-pull signal. The polarity inverter
117
judges whether the track accessed is a land or a groove according to control signal L
4
from the system controller
118
, inverting the polarity, for example, only when the track is a land. The tracking controller
116
outputs tracking control signal to the driver
122
according to the level of tracking error signal input, the driver
122
supplies current to the actuator according to this signal to control the position of the objective lens
104
in the radius direction across the recording track. Thereby, the optical spot can scan precisely on the track.
On the other hand, the adder amplifier
109
current-voltage-converts (I-V conversion) two currents output from the light-receiving part
108
, adding both, outputting it as add signal to the waveform shaper
112
. The waveform shaper
112
shapes data signal and address signal with an analogue waveform into a pulse waveform by data-slicing by a certain threshold value, outputting it to the playback signal processor
113
and the address playback circuit
114
. The playback signal processor
113
demodulates digital data signal input, conducting the processing of error correction etc. to output it as playback data. The address playback circuit
114
demodulates digital address signal input, outputting it as position information on the disk to the address calculator
115
. The address calculator
115
calculates the address of a sector accessed from address signal read out from the optical disk
100
and land/groove signal from the system controller
118
. The calculation method is to judge referring to an address map etc. and then output the judgement signal.
The system controller
118
judges whether the light beam currently locates at a desired address based on this address signal. The traverse controller
121
outputs drive current to the traverse motor
107
according to control signal from the system controller
118
when shifting the optical head
101
, thereby the optica

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