JP2892327B2 - Disk recording and playback device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] [0001] The present invention relates to a magneto-optical disk or the like.
Disk for recording and reproducing data using the
The present invention relates to a recording / reproducing apparatus. [0002] 2. Description of the Related Art Conventionally, large rewritable data can be used.
A magneto-optical disk is known as a recording medium having a large capacity.
Writing and reading data to and from the magneto-optical disk
For erasing and erasing, laser diodes are usually used.
The light is used. Conventionally, data write and erase operations
During operation, the period during which laser light must be actually irradiated
Always keep the laser diode operating during periods other than
The life of the laser diode is short,
Needed to replace the laser diode. Tracks on a magneto-optical disk are duplicated.
Is divided into a number of sectors, and each sector absorbs time errors, etc.
To provide synchronization for each sector.
Data is recorded on a sector-by-sector basis.
Management is being done. [0004] As described above, in the prior art,
However, there is a problem with the life of the laser diode.
Each sector of the track on the magneto-optical disk
The gap area provided becomes an invalid recording area,
There is a problem that the effective capacity is reduced. Accordingly, the present invention has been made to solve the above-mentioned conventional problems.
In view of the above, it is possible to extend the life of the laser diode.
And effective use of disk capacity
To provide a disk recording / reproducing apparatus having the above configuration
It is assumed that. [0006] DISCLOSURE OF THE INVENTION A disk storage device according to the present invention is provided.
The recording / reproducing apparatus includes a plurality of pits formed in advance.
And the data area where data is written
Disc-shaped notes alternately provided along the circumferential direction
By irradiating the recording medium with at least laser light
For disk recording / reproducing devices that reproduce or record data
Playback of the data recorded in the data area
Read operation mode and write data to the data area.
The above laser light is applied in accordance with the write operation mode for recording.
A laser that controls the drive current to the emitting laser diode
The read operation mode and the write operation
Detect pits in the above pit area during operation mode
A detection circuit and a plurality of pits detected in the pit area;
Unique pattern detection cycle to detect a specific unique pattern from
Path and detection output obtained by the unique pattern detection circuit
Synchronize with a predetermined pit among the above plurality of pits based on
A pulse generation circuit for generating a reference clock,
The laser drive circuit operates during the write operation mode.
During the period corresponding to the pit area,
The operation mode is synchronized with the reference clock.
Drive with a drive current controlled to correspond to the
And during the period corresponding to the data area
From the above read operation mode synchronized with the reference clock
Pulsed laser diode with large drive current
By driving, the data following the pit area is
Data is recorded in the data area. [0007] [0008] BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described.
This will be described in detail with reference to the drawings. FIG. 1 shows a disk according to an embodiment of the present invention.
Pattern of Magneto-Optical Disk Used as Shaped Recording Medium
Is schematically shown. In FIG. 1, a magneto-optical disk 1 is
For example, the diameter is about 13cm, and 300M
Memory capacity. This disk 1 has a square
It rotates at a constant speed, and as one track per rotation,
For example, data is recorded by forming a track 2 concentrically.
It is. The number of tracks on one side is about 18,000 to 20,000
Each track is divided into, for example, 32 sectors.
Have been. Each of the above tracks is enlarged in FIG.
As shown, a pit area 2a having servo pits
And a data area 2b to which data is written.
These are alternately provided along the circumferential direction.
Each length of the pit area 2a and the data area 2b is
When converted to a unit, for example, the pit area 2a is 2 bytes.
The data area 2b is 16 bytes. As shown in FIG.
U, three pits P_A, P_B, P_CAre each formed
Have been. Pit P_A, P_BIs formed on the disc 1
Off the center line of the track
Formed and the pit P_CIs formed on the center line
ing. Each of these pits P_A, P_B, P_CHas a diameter of 0.
5 to 1.0 μm, and the actual length L of the pit area
Is about 15 to 30 μm. FIG. 4 shows the disk 1 in the radial direction (FIG. 1).
Each pit P in the direction of the arrow at_A, P_B, P_CArrangement
The row state is shown. That is, each of the pits P_B, P
_CAre arranged linearly, and the pit P_AIs every 16
Are arranged in the longitudinal direction of the track.
You. Pit P shifted position every 16 above_AArray of
Determines the track number currently being scanned by the optical pickup.
Used to perform a traverse count described below
Is done. The pit P_AIs the sample pulse SP
₁Or sample pulse SP_TwoSampled by
And each pit P_B, P_CIs the sample pulse S
P_Three, SP_FiveSampled at
The pit P_BAnd pit P_CSpecular area between samples
Pulse SP_FourSampled by each
Used for various kinds of servos and clock generation. FIG. 5 shows a magneto-optical disk drive to which the present invention is applied.
1 shows the overall configuration of the device. In this magneto-optical disk drive, the input terminal
The child 11 has an interface from a computer or the like.
Data D to be recorded via_IIs supplied. This de
Data D_IIs transmitted to the modulation circuit 12 and includes bit conversion and the like.
After the predetermined modulation is performed, the data is sent to the laser drive circuit 13.
It is. The laser drive circuit 13 is connected to the interface
Control of each mode of writing, reading or erasing from
Control signal is given, and the optical pickup is
Signal for driving the laser diode 21 of the pump 20
Output and becomes the reference clock when recording and erasing data.
Drive in accordance with the channel clock CCK
Pulse signal and high-frequency drive signal for reading
Is supplied to the laser diode 21. The optical pickup 20 is provided with the laser
In addition to the diode 21, the photodiode 22 and it
The two photodetectors 23 and 24 divided into four parts respectively
Consists of The photodiode 22 is connected to the photodiode
The intensity of the laser light emitted from the laser diode 21 is detected.
Things. In addition, the photodetectors 23 and 24
Reflects the reflected light of the laser beam from the magneto-optical disk 1.
Each is detected via an analyzer, one of which is
The plus direction component of the rotation angle is detected, and the other is
A negative component has been detected. The motor 14 has a motor servo circuit 1
5, for example by PLL (Phase Locked Loop)
Servo is performed, and the disk 1 is moved at a predetermined speed.
(Angular velocity) to rotate accurately. Then, the laser diode 21
When the laser light is applied to the magneto-optical disk 1,
Both enter the photodiode 22. Above
Of the photodiode 22 according to the light intensity of the laser light.
The force is sampled and held via the DC amplifier circuit 16.
(S / H) circuit 17. This S / H circuit 17
Then, sample pulse SP_Four(See FIG. 4)
A pull-hold operation is performed, and this output is APC (Auto
matic Power Control)
It is supplied to the drive circuit 13 as an APC control signal. This
As a result, the laser diode 21 outputs
The light intensity of the laser beam is maintained at a predetermined value.
You. Reflection of the laser beam by the disk 1
The above optical pick-up where light enters through an analyzer (not shown)
Output of photo detectors 23 and 24 of backup 20
Are sent to the preamplifier circuit 31, respectively. This prefix
From the width circuit 31, the photodetectors 23 and 24
A light detection signal S which is a sum signal of outputs from the respective light receiving regions._A
(S_A= A + B + C + D + A '+ B' + C '+ D')
(Including DC component) directly to the focus servo circuit 32
As well as output from each light receiving area
Light detection signal S_B[S_B= (AC-BD) + (A'C'-
B′D ′)] is the sample pulse SP_FourAccording to the sump
Via the S / H circuit 33 which performs a full hold operation.
It is sent to the focus servo circuit 32. And the above
Each of the signals S_A, S_BBased on
The focus servo control signal generated during
Is sent to the backup 20 for focus control.
It has become so. Further, light detection from the preamplifier circuit 31 is performed.
Signal S_C(S_C= A + B + C + D + A '+ B' + C '+
D ′) is a peak value detection circuit 41, S / H circuits 51 and 5
2, 53 and the sampling clamp circuit 61 respectively
Sent. The light detection signal SC is the pit of the disk 1.
It is a detection signal of a concavo-convex pattern in a region 2a. the above
In the peak value detection circuit 41, the peak of the light detection signal SC is obtained.
Is detected, and further transmitted to the unique pattern detection circuit 42.
The pit P on the disk 1_B, P_COnly in between
Detect pit patterns with given intervals
The pit P_CIs detected, and this detection output is
The signal is sent to the pulse generation circuit 44 via 43. And
The pulse generation circuit 44 detects the unique pattern
Based on the detection output obtained on the road 42, the pit P_C
Channel clock CC as the reference clock synchronized with
Generates K, byte clock SBC, servo
Byte clock SBC and sample pulse SP₁, SP
_Two, SP_Three, SP_Four, SP_FiveIs formed and output (FIG. 4)
reference). The channel clock CCK is not shown.
However, it is supplied to all circuit blocks. Above sun
Pull pulse SP₁Is supplied to the S / H circuit 51,
Lupulse SP_TwoIs supplied to the S / H circuit 52, and the sample
Pulse SP_ThreeAre supplied to the S / H circuit 53. Ma
Sample pulse SP_FourAre the S / H circuits 17, 33
And a sampling clamp circuit 6
1,62. Note that the sample pulse SP
_FiveIs used for detecting the moving direction of the optical pickup 20, for example.
Used. Further, the peak value detection circuit 41 and the
The pattern detection circuit 42 includes the pulse generation circuit 44
Are supplied with gate pulses. In each of the S / H circuits 51, 52, 53,
The supplied light detection signal S_CAbout each sample pal above
SP₁, SP_Two, SP_ThreeSample and hold operation
Is performed. The output from the S / H circuit 51 and the S / H
The output from the H circuit 52 is leveled by the comparator 54.
Comparisons are made. This comparison output is based on the pit P_A
16 tracks in relation to the radial arrangement on the disc 1
The signal is inverted every time the signal is
It is sent to the King Servo / Seek circuit 55 and
It is sent to the multiplexer 56. This multiplexer 56
From among the signals from the S / H circuits 51 and 52
, The higher level signal is selectively output and the subtraction circuit 5
7 In the subtraction circuit 57, the multiple
And the signal from the S / H circuit 53
The difference signal of
It is sent to the tracking servo / seek circuit 55. So
Then, this tracking servo / seek circuit 55
Tracking control and feed control of the optical pickup 20
I do. The sampling clamp circuit 61
Has the light detection signal S_CHowever, the sampling
The lamp circuit 62 has a light detection signal S_D[S_D= (A + B +
C + D)-(A '+ B' + C '+ D')]
It is supplied from the preamplifier circuit 31.
The light detection signal S_CIs the disc 1
7 is a detection signal of a concavo-convex pattern in the scanning region 2a. Ma
In addition, the light detection signal S_DIs the data area 2 of the disk 1
This is a detection signal of the data written in b. Each of the above
The sampling clamp circuits 61 and 62
Pulse SP_FourEach signal is clamped by
The signal is sent to the multiplexer 63. This multiplexer 6
No. 3 indicates that the switching selection operation is performed for sync detection / address decoding.
Controlled by a control signal from the code circuit 64
Has become. For example, first, the light detection signal SC is
Through the clamping clamp circuit 61 and the multiplexer 63
Sent to the analog / digital (A / D) converter 65
After being converted to a digital quantity, it is sent to the demodulation circuit 66.
Then, the output from the demodulation circuit 66 is sync detected / added.
Sent to the decoding circuit 64,
Detection is performed and address information is decoded.
Done. And from a computer etc.
Address information of the data to be read supplied through the
Information and the actual address match.
Switching control of the multiplexer 63
As a result, the light detection signal S for the data area 2b_DIs A /
Sent to the D converter 65 and the demodulation circuit 66,
7 obtained by performing demodulation processing including bit conversion.
Data D_OIs output. This data D
O is sent to a computer etc. through the interface
You. When writing data, the sync detection /
The control signal is sent from the address decode circuit 64 to the modulation circuit 12.
Is sent from the modulation circuit 12 in response to the control signal.
Data to be written is sent to the laser drive circuit 13.
It has become. Here, the specific structure of the laser drive circuit 13 is described.
An example is shown in FIG. FIG. 6 shows a laser diode.
1 and the APC circuit system are shown together. In this configuration example, a read operation is instructed.
Control pulse is supplied to the terminal 71,
A control pulse for instructing an operation or an erasing operation is supplied to terminal 75.
It is supplied to. The terminal 71 is connected to the transistor Q₁Through
Transistor Q_TwoConnected to the base. This tiger
Transistor Q_TwoIs the transistor Q_ThreeAnd collector and Emi
Are commonly connected. The above transistor Q
_ThreeIs the transistor Q_FourBase and resistance R₁
It is connected to the. The above transistor Q_FourThe emitter is
Through the diode 72, the transistor Q_ThreeBase of
It is connected to the. Each of the above transistors Q_Three, Q_Fouras well as
The diode 72 forms a ring oscillator.
Also, the transistor Q_ThreeTransistor Q_FiveIs
The transistor Q for the current source₆Connection to all collectors
And the transistor Q₆Of the resistor R_Two
Is connected to the power supply terminal 73 via the. In addition,
Transistor Q_FiveHas a predetermined base voltage V_BBgive
Terminal 74. The terminal 75 is connected to the transistor Q₇To
Through the transistor Q₈Connected to the base. This
Transistor Q₈Is a laser diode 2
1 and the transistor Q_Fiveof
Connected to collector. Also, the transistor Q
₉Means that the collector is a resistor R_ThreeGrounded through
The base is connected to the terminal 74. the above
Each transistor Q₈, Q₉Means that each emitter is
Transistor Q_TenAre connected in common to the
Transistor Q_TenOf the resistor R_FourThrough the power end
Child 73. Radiated from the laser diode 21
Photodiode 22 for detecting the intensity of laser light
Is the resistance R_FiveAnd for DC amplification
Connected to the switching element 77 via the operational amplifier 76
Have been. The switching element 77 includes a capacitor C
₁Amplification as a buffer with high input impedance
Unit 78. The switching element 77
Is the sample pulse SP_FourIs supplied and the above
The above photo diode supplied via an operational amplifier 76
Output of the sample pulse SP_FourSampler at
The capacitor C₁Sample to hold
・ Perform a hold operation. The output of the operational amplifier 78 is
The power terminal is connected to each inverting input terminal of each of the operational amplifiers 79 and 80 by a resistor.
R₆Connected through. Each of the operational amplifiers 79,
80 is a reference voltage V at each non-inverting input terminal._REFGiven
And one output terminal is the transistor Q₆At the base of
Connected, and the other output terminal is connected to the transistor Q_TenBee
Connected to the Further, the inversion of the operational amplifier 80 is performed.
The input end is a resistor R₇Connected to the terminal 81 via
You. The terminal 81 has a write operation mode and an erase operation.
Switching control of output of laser diode 21 between modes
A control signal is supplied to perform the operation. Next, the laser driving circuit having the above-described configuration will be described.
The operation will be described. When the terminal 71 is at a low (L) level
Is the transistor Q₁, Q_TwoIs kept off,
Each transistor Q_Three, Q_FourRing oscillator
For example, a high-frequency oscillation operation of about 700 MHz to 1 GHz is performed.
U. As a result, the laser diode 21 becomes a current source transistor.
Transistor Q₆Current i_CSHWith high peak
Wave current is transistor Q_FiveSupplied via the high frequency drive
Be moved. When the terminal 71 is at a high (H) level,
Each transistor Q₁, Q_TwoIs on
As a result, the transistor Q₆Current i
_CSHIs the transistor Q_TwoThrough the resistor R₁Flows to
When the drive of the laser diode 21 is stopped,
Then, the oscillation operation of the ring oscillator is also stopped. The high frequency current of the laser diode 21
Drive is controlled to L level in the read operation mode.
The control pulse is supplied to the terminal 71.
You. When the terminal 75 is at the L level,
Each transistor Q₇, Q₈Is held off for the current source
Transistor Q_TenCurrent i_CSSIs transistor Q
₉Through the resistor R_ThreeAnd the laser diode 21
Not flowing. When the terminal 75 is at the H level,
Transistor Q₇ , Q₈Is turned on for the above current source
Transistor Q_TenCurrent i_CSS Is above Transis
TA Q₈ Flows to the laser diode 21 through. Soshi
In this embodiment, for example, the write operation mode
Sometimes, a control pulse corresponding to the data is supplied to the terminal 75.
To supply the laser diode 21 to the
Write data by pulse driving according to the data
I'm trying to do it. Further, the operation of the laser drive circuit will be described.
This will be specifically described with reference to FIG. Note that this
FIG. 7 shows a current value i supplied to the laser diode 21._LD
Shows the waveform of the current in the write operation mode.
The waveforms are shown in FIG.
The current waveform is shown in FIG.
FIG. 7 (C) shows the current waveform in the standby operation mode.
The current waveform in the mode is shown in FIG. In the write operation mode, the above-mentioned pit area
During the period corresponding to the region 2a, both terminals 71 and 75 are at L level.
As shown in FIG. 7 (A),
As described above, the laser diode 21 is driven by a high-frequency current.
Is done. Also, during the period corresponding to the data area 2b,
While holding the terminal 71 at H level,
By supplying a data pulse corresponding to the write data
By driving the laser diode 21 in pulses,
Write data. This write operation timing
That is, the timing of the data pulse is determined by the pit P_Cof
The channel clock C formed based on the detection output
The timing coincides with CK. Here, the period corresponding to the pit area 2a is set.
During this time, various operation modes other than this write operation mode
The laser diode 21 is always high frequency current
, And a reading operation is always performed. In the erase operation mode, the data area 2b is
During the corresponding period, the terminal 71 is held at the H level,
By repeatedly supplying a pulse to the terminal 75,
As shown in FIG. 7B, the laser diode
21 is pulse-driven to perform a data erasing operation. this
The timing of the erase operation, that is, the
The timing also coincided with the channel clock CCK.
It's time. In the read operation mode, the pit area 2a
And the period corresponding to the data area 2b, that is, during the entire period
To keep both terminals 71 and 75 at L level.
As shown in FIG. 7C, the laser diode
Drive 21 with a high-frequency current to read data.
Do. Further, in the standby operation mode,
As shown in (D), during the period corresponding to the data area 2b
While the terminal 75 is held at the L level,
The drive of the arm 21 is stopped, and the pit area 2a is stopped.
Perform only reading. Here, in any of the above operation modes,
However, the APC circuit composed of the photodiode 22 etc.
By the operation of the road system, the transistor Q₆ And transi
Star Q_TenAPC is controlled for each base of
So that the output (light intensity) of Aether 21 is maintained at a predetermined value
Has become. In the erase operation mode, the recording operation mode is set.
Drive current larger than that at the time of
So that the erasing operation is performed reliably.
Control signal voltage to be applied to the write operation mode and the erase operation mode.
The value is set differently with the code. As described above, the data write operation mode
The laser diode 21 during
By efficiently pulse driving the laser diode,
The life of the card 21 can be extended, and power saving can be achieved.
At the same time, radio interference and the like can be reduced. Next, another specific example of the laser driving circuit 13 will be described.
FIG. 8 shows a configuration example. It should be noted that in FIG.
The diode 21 and the APC circuit system are shown together.
is there. Also, the components corresponding to the configuration example shown in FIG.
For the minutes, the same reference numerals are given in FIG.
Detailed description is omitted. In this configuration example, the control pulse is supplied.
Terminal 91 is a transistor Q₁₁Through the transistor
Q₁₂And transistor Q₁₃Connected to each base
You. The above transistor Q₁₂The collector of the resistor R₈Through
And grounded. Also, the transistor Q₁₄Is that
The collector is connected to the laser diode 21 and
Has a predetermined base voltage V_BBTerminal 92
Has been continued. Each of the above transistors Q₁₂, Q₁₄Is
Mitter is transistor Q for current source_TenCommon to all collectors
It is connected. The above transistor Q_TenThe base of
Laser diode 2 between recording operation mode and erasing operation mode
The control signal for switching and controlling the drive current flowing in
It is connected to the terminal 93 to be supplied. The transistor Q_FifteenThe collector is a tiger
Transistor Q₁₆Base and resistance R₉It is connected to the.
The above transistor Q₁₆Is via a diode 94
And the transistor Q_FifteenConnected to the base.
Each of the above transistors Q_Fifteen, Q₁₆And the diode 94
It constitutes a ring oscillator. Also transistors
Q₁₇Has its collector connected to the laser diode 21.
And its base is a predetermined base voltage V_B´_BTo
The terminal 95 is connected to the input terminal 95. The above transistor Q
_FifteenAnd transistor Q₁₇Means that each emitter is a transistor Q
₁₃Are commonly connected to the collector. Also Transis
TA Q₁₈Is the collector of the laser diode 21
The base is connected to the terminal 92.
ing. Further, each transistor Q₁₃, Q₁₈Is
Mitter is transistor Q for current source₆Common to all collectors
It is connected. Next, in the laser driving circuit having the above-described configuration,
The operation will be described. When the terminal 91 is at the L level,
Transistor Q₁₁, Q₁₂, Q₁₃Is off and each transistor Q
₁₄, Q₁₈Is turned on. Therefore, laser diode
The transistor Q includes the transistor Q₁₄Electricity flowing through
Flow i_CSSAnd the transistor Q₁₈Current flowing through
i_CSHAre supplied. That is, the laser diode
Do 21 contains (i_CSS+ I_CSH) Becomes the driving current supplied
From the APC circuit system.₆At the base of
Write operation mode is controlled by the supplied APC control signal.
APC is also performed during the operation and the erase operation mode. When the terminal 91 is at the H level,
Each of the above transistors Q₁₁, Q₁₂, Q₁₃Is on and each tiger
Transistor Q₁₄, Q₁₈Is turned off. And each tiger
Transistor Q_Fifteen, Q₁₆But high frequency as a ring oscillator
Performs oscillation operation. As a result, the laser diode 21
Transistor Q for current source₆Current i_CSHThe peak
The value of the high-frequency current is transistor Q₁₃, Q₁₇Through
It is supplied and driven at high frequency. At this time, the transistor Q
_TenCurrent i_CSSIs the transistor Q₁₂Through the resistance
R₈Flows to Further, the operation of the laser drive circuit will be described.
This will be specifically described with reference to FIG. Note that this
FIG. 9 shows a current value i supplied to the laser diode 21._LD
Shows the waveform of the current in the write operation mode.
The waveform is shown in FIG.
The current waveform is shown in FIG.
FIG. 9 (C) shows the current waveform at this time. In the write operation mode, the data area 2b
During the period corresponding to the
9A is supplied to the terminal 91 so that the terminal shown in FIG.
As described above, the laser diode 21 is pulse-driven.
Thus, data is written to the data area 2b. This
Here, the terminal where the data pulse does not exist is at the H level.
During the period of the transistor Q_Fifteen, Q₁₆Ring
By performing the oscillation operation as an oscillator,
The user diode 21 is driven by the high-frequency current. This
High-frequency drive for actual data write operation
On the other hand, by giving the preheating effect by the so-called pre-heat,
A writing operation can be performed. In the erasing operation mode, as shown in FIG.
As described above, while driving the laser diode 21 at a high frequency,
A predetermined repetition period during a period corresponding to the data area 2b
By supplying the erase pulse of
The laser diode 21 is pulsed and the data
The erasing operation of the area 2b is performed. Further, in the read operation mode,
By holding the child 91 at the H level, the state shown in FIG.
As shown in FIG.
To read data. In the circuit shown in FIG.
Transistor Q_TwoAnd transistor Q₈Connect each base
Even if one input control pulse is supplied,
Operations similar to those shown in FIG. 9 can be performed. [0051] As described above, the disk storage according to the present invention is described.
In the recording / reproducing device, detection and detection of pits in the pit area
Read operation for reproducing data recorded in the data area
Operation mode and a write operation for recording data in the data area.
Laser that emits laser light according to the operating mode
Drive current to diode is controlled by laser drive circuit
In the write operation mode,
The laser diode in read mode during
Driven by the corresponding drive current and detected in the pit area
Of a plurality of pits synchronized with a predetermined pit
The quasi-clock is generated by the pulse generation circuit and the data
Synchronized with the reference clock during the period corresponding to the area
Due to the larger drive current than in the read mode,
Pulse the laser diode to the above data area.
And record the data. That is, each area
The drive current of the laser diode in response to
Laser without using unnecessary laser power
The life of the diode can be extended by reducing the load on the diode.
You. Also, servo pits in the pit area provided on the disc
The laser die is synchronized with the reference clock timing synchronized with the
By pulse driving the arm, the same
To write data to the data area
Is necessary for conventional magneto-optical discs.
This eliminates the need for a gap region for absorbing
The effective capacity of the disk can be increased. Further, a disk recording / reproducing apparatus according to the present invention
From the pits detected in the pit area
A unique pattern detection circuit that detects a predetermined unique pattern
Based on the detection output obtained from the plurality of pits,
The reference clock synchronized with the predetermined pit in
It can be generated reliably by the generation circuit,
The reference clock synchronized with the servo pits in the pit area
Pulses the laser diode at the timing of the
Data to the data area by synchronizing the entire disk
Can be written.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing a recording pattern of a magneto-optical disk used as a disk-shaped recording medium in a disk recording / reproducing apparatus according to the present invention. FIG. 2 is a schematic diagram showing a configuration of each track on the magneto-optical disk. FIG. 3 is a schematic diagram showing a configuration of each pit area in the magneto-optical disk. FIG. 4 is a schematic diagram showing an arrangement state of pits existing along a radial direction of the magneto-optical disk. FIG. 5 is a block diagram showing an overall configuration of a disk recording / reproducing apparatus according to the present invention. FIG. 6 is a circuit diagram showing a specific configuration example of a laser drive circuit in the disk recording / reproducing apparatus. FIG. 7 is a timing chart for explaining the operation of the laser drive circuit. FIG. 8 is a circuit diagram showing another specific configuration example of the laser drive circuit. FIG. 9 is a timing chart for explaining the operation of the laser drive circuit shown in FIG. [Description of Signs] 1 magneto-optical disk, 2a pit area, 2b data area, 12 modulation circuit, 13 laser drive circuit, 14
Motor, 15 motor servo circuit, 21 laser diode, 41 peak value detection circuit, 42 unique pattern detection circuit, 44 pulse generation circuit

Claims (1)

(57) [Claims] A pit area composed of a plurality of pits formed in advance and a data area in which data is written are at least irradiated with a laser beam onto a disk-shaped recording medium provided alternately along the circumferential direction. In the disk recording / reproducing apparatus for reproducing or recording, the laser beam is emitted according to a read operation mode for reproducing data recorded in the data area and a write operation mode for recording data in the data area. A laser drive circuit for controlling a drive current to the laser diode; a detection circuit for detecting pits in the pit area in the read operation mode and the write operation mode; and a predetermined unique pattern from a plurality of pits detected in the pit area A unique pattern detection circuit for detecting the A pulse generation circuit that generates a reference clock synchronized with a predetermined pit of the plurality of pits based on a detection output obtained on a road. During the period corresponding to the region, the laser diode is driven by a drive current controlled to correspond to the read operation mode in synchronization with the reference clock, and during the period corresponding to the data region, the laser diode is driven by the reference clock. A disk recording / reproducing apparatus for recording data in the data area following the pit area by pulse-driving the laser diode with a larger drive current than in the synchronized read operation mode.