Dynamic information storage or retrieval – Binary pulse train information signal – Format arrangement processing for auxiliary information
Reexamination Certificate
2000-10-25
2002-01-08
Young, W. R. (Department: 2651)
Dynamic information storage or retrieval
Binary pulse train information signal
Format arrangement processing for auxiliary information
C369S275300, C369S124070
Reexamination Certificate
active
06337839
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an optical disk and an optical disk drive apparatus. More specifically, the invention relates to an optical disk for recording data both onto the recording tracks in depressed portions formed by guide grooves and onto the recording tracks in protruding portions between the guide grooves, and an optical disk drive apparatus which uses the optical disk according to the present invention. In recent years, in order to enhance a recording density of a large-capacity rewritable optical disk, a data recording method of recording data both onto guide grooves and onto lands therebetween has been studied. This method is generally referred to as a land-groove recording method. When this recording method is used, a higher recording density can be obtained. This is because the track pitch can be reduced by half compared to the case where only groove tracks are used for data recording. Now, a conventional optical disk drive apparatus which uses the land-groove recording method is described.
FIG. 9
is a block diagram showing a structure of an optical disk drive apparatus which is described in Japanese Unexamined Patent Publication 6-176404. Referring to
FIG. 9
, the optical disk drive apparatus is shown schematically for use with an optical disk
100
. The optical disk drive apparatus includes a semiconductor laser
101
for emitting a laser beam. A collimator lens
102
converts the laser beam from the semiconductor laser
101
into a parallel beam. A half mirror
103
receives the beam and directs it toward an objective lens
104
, which focuses the beam onto the optical disk
100
. A photodetector
105
receives the reflected beam from the optical disk
100
. The photodetector
105
includes two light-receiving parts divided by a boundary line parallel to the tracks of the optical disk
100
so as to obtain a tracking error signal. The optical disk drive apparatus further includes an actuator
106
for driving the objective lens
104
, an optical head
107
enclosed by a dotted line and mounted on a head base, and a differential amplifier
108
for receiving a detection signal from the photodetector
105
. A tracking polarity reversal circuit
109
receives the tracking error signal from the differential amplifier
108
and does or does not reverse the polarity of the tracking error signal, in response to a control signal T
1
from a system controller
121
. When the tracking error signal is supplied from the differential amplifier
108
to the tracking controller
110
without having its polarity reversed, the beam spot is pulled into a groove track. The tracking controller
110
receives an output signal from the tracking polarity reversal circuit
109
and a control signal T
2
from the system controller
121
and supplies tracking control signals to a driving circuit
120
and a traverse motor controller
116
.
A summing amplifier
111
receives detection signals from the photodetector
105
and supplies the sum of the signals. A waveform shaping circuit
112
receives a high-frequency component of the sum of the signals from the summing amplifier
111
and supplies digital signals to a reproduced signal processor
113
and an address reproduction circuit
114
respectively. The reproduced signal processor
113
supplies reproduced data to an output terminal. The address reproduction circuit
114
receives the digital signal from the waveform shaping circuit
112
and supplies an address signal to an address calculator
115
. The address calculator
115
receives the address signal from the address reproduction circuit
114
and the control signal T
1
from the system controller
121
and supplies the correct address signal to the system controller
121
. The traverse motor controller
116
provides a driving current to a traverse motor
117
in response to a control signal T
3
from the system controller
121
. The traverse motor
117
moves the optical head
107
in the radial direction of the optical disk
100
. A recording signal processor
118
receives recording data and supplies a recording signal to a laser diode (LD) driving circuit
119
. The LD driving circuit
119
receives a control signal T
4
from the system controller
121
and the recording signal from the recording signal processor
118
and supplies a driving current to the semiconductor laser
101
. The driving circuit
120
supplies a driving current to the actuator
106
. The system controller
121
supplies the control signal T
1
to the address calculator
115
and the tracking polarity reversal circuit
109
, the control signal T
2
to the tracking controller
110
, the control signal T
3
to the traverse motor controller
116
, and the control signal T
4
to the recording signal processor
118
and the LD driving circuit
119
.
The operation of the conventional optical disk drive apparatus having the above-mentioned structure is described with reference to FIG.
9
. The laser beam emitted from the semiconductor laser
101
is made to be parallel by the collimator lens
102
, passed through the half mirror
103
which is used as a beam splitter, and focused onto the optical disk
100
by the objective lens
104
. The beam reflected from the optical disk
100
contains data on data recording tracks. The reflected beam is passed through the objective lens
104
and directed to the photodetector
105
by the half mirror
103
. The photodetector
105
detects the strength and distribution of light in the incoming beam, converts it to electrical signals, and supplies them to the differential amplifier
108
and the summing amplifier
111
. The differential amplifier
108
applies a current-to-voltage conversion to the input currents, and in response to a potential difference between the input terminals thereof, produces a push-pull signal representing the difference between the two input signals. In response to the control signal T
1
from the system controller
121
, the tracking polarity reversal circuit
109
determines whether a track being accessed by the optical head is a land track or a groove track and reverses a tracking polarity only when the track being accessed by the optical head is a land track, for example. The tracking controller
110
supplies a tracking control signal to the driving circuit
120
according to the level of the tracking error signal received. In response to the tracking control signal, the driving circuit
120
supplies a driving current to the actuator
106
and controls the position of the objective lens
104
perpendicularly to the direction of the data recording tracks. The beam spot thereby scans the data recording tracks accurately.
The summing amplifier
111
receives output currents from the photodetector
105
, applies a current-to-voltage conversion to them, and supplies the sum of the input signals to the waveform shaping circuit
112
. The waveform shaping circuit
112
binarizes a data signal and an address signal in analog waveform in accordance with a predetermined threshold value and supplies the digital data signal and the digital address signal to the reproduced signal processor
113
and the address reproduction circuit
114
, respectively. The reproduced signal processor
113
demodulates the input digital data signal, applies an error correction to the demodulated digital data, and supplies resultant data as reproduced data.
The address reproduction circuit
114
demodulates the input digital address signal and supplies disk position data to the address calculator
115
. The address calculator
115
calculates the address of a sector being accessed by the optical head based on the address read from the optical disk
100
and the control signal T
1
from the system controller
121
indicating whether a track being accessed is a land track or a groove track. The manner of address calculation will be described later. Based on the address signal, the system controller
121
determines whether the light beam is scanning a desired sector.
In response to the control signal T
3
from the system controller
Gotoh Kenji
Ishida Yoshinobu
Nagasa Masato
Nakane Kazuhiko
Ohata Hiroyuki
Mitsubishi Denki & Kabushiki Kaisha
Young W. R.
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