JPH03259434A - Optical information recording and reproducing device - Google Patents

Abstract

PURPOSE:To prevent deterioration of C/N by changing simultaneously recording power of a laser and a recording pulse width corresponding to a disk inner/outer circumferential position detected by a regenerative signal from the disk. CONSTITUTION:An inner/outer circumferential position of the disk 1 is detected by a laser control driving means 80 with the regenerative signal read out of the disk 1, and the recording power and the recording pulse width of the laser 11 are changed simultaneously in accordance with the detected disk inner/outer circumferential position. For example, the recording power is lowered in an inner/outer circumference of the disk 1 by a laser control means, and also the recording pulse width is narrowed, while the recording power is raised in an outer circumference of the disk 1, and also the recording pulse width is widened, so that the recording power and the recording pulse width are worked to be corresponding to an inner/outer circumferential linear speed ratio. By this method, a signal of high C/N can be obtained, while the need for a high output is eliminated.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to optical information recording and reproducing devices such as rewritable write-once optical disk devices and magneto-optical disk devices, and in particular to optical information recording and reproducing devices such as rewritable write-once optical disk devices and magneto-optical disk devices. The present invention relates to a recording method that simultaneously switches recording power and recording pulse width to obtain a signal with a high C/N (signal/noise ratio) and to extend laser life.

(Conventional technology) Conventionally, as a technology in this field, there is a technology written by Kazuo Terada.
"Key Points of Optical Pickup System Design", C61 (1984)
-10-31> Japan Industrial Technology Center, P, 151, 1
There was one described in 52.161.

As described in this document, conventional optical information recording and reproducing devices, such as optical disk devices, irradiate a laser beam onto a disk and detect focus errors (focusing errors) and tracking errors (disk an optical pickup that detects a trace error for the track of the track and outputs a detection signal for controlling a focus servo and a tracking servo; a servo error signal generating means that outputs a focus error signal and a tracking error signal from the detection signal; A drive means that outputs a focus drive current and a tracking drive current based on an error signal and a tracking error signal, and an actuator that moves the optical pick-up in a focus direction and a tracking direction using the focus drive current and tracking drive current. It is equipped with

In this optical disk device, the disk is rotated by, for example, a spindle motor, and based on a focus error signal and a tracking error signal outputted from a servo error signal generation means, a drive means moves the light, the ncua, and the knob in the focus direction and direction through an actuator. Feedback control (servo) is performed to move in the tracking direction to eliminate focus errors and tracking errors, and information is recorded or reproduced on the disk.

Methods for recording this type of information include methods such as write-once optical discs, in which holes are heated in a focused shape by laser light, or magneto-optical discs, in which a magnetic field is applied perpendicularly to the disc. , made silent by laser light,
There is a method of reducing the perpendicular magnetic field by utilizing the characteristic that the coercive force decreases when the temperature exceeds the Curie point.

On the other hand, the innermost circumferential position of the disk (for example, γ = 30 mm>
, the linear velocity (i.e., moving speed) at the outermost circumferential position (for example, r = 60 mm) is the number of revolutions of the disk, for example, 3600
rpm, 11°3 m7/sec at the innermost circumference, 22 at the outermost circumference
．． 6m/sec, which is significantly different. Because the linear velocities differ in this way, when the disk is heated with laser light of the same power, the temperature rise at the inner periphery where the linear velocity is small is greater than the temperature rise at the outer periphery where the linear velocity is large. Therefore, when recording on the inner and outer peripheries with the same recording power, both in the conventional write-once type and in the magneto-optical type, the recording pits on the inner periphery become larger than the planned pits, or the recording pits on the outer periphery become larger than the planned pits. becomes smaller.

Therefore, in order to solve this problem, conventional methods have been adopted: ■ A method in which the recording pulse width is fixed and the recording power is varied between the inner and outer circumferences, or ■ A method in which the recording power is fixed and the recording pulse width is varied between the inner and outer circumferences. .

(Problem to be solved by the invention) However, in the above configuration, ■method of changing the recording power;
and (2) the method of changing the recording pulse width had the following drawbacks.

■ Method of changing the recording power On the inner circumference of the disk, the pit length is short and there is interference due to temperature rise between adjacent pits, so it is better to increase the recording power of the laser beam and make the recording pulse width as small as possible to reduce interference. The C/N ratio increases by, for example, 2 to 3 dB. Therefore, if the recording pulse width is made small according to the recording on the inner circumference of the disk, then on the outer circumference of the disk,
As the recording pulse width is reduced, the recording power of the laser beam must be increased, and a high power output of the laser is required at the outer periphery of the disk.

In general, lasers, such as semiconductor lasers, are expensive due to their element characteristics and large area for forming the element, and when used at high output, the life of the laser is significantly shortened due to deterioration of the element.

In this way, when only the recording power is changed while the recording pulse width is fixed, a high-output laser is required, which shortens the life of the laser, increases the price of the laser itself, and increases the circuit scale of the laser drive circuit. There was a problem.

■ A method of changing the recording pulse width while keeping the recording power fixed When the disk is rotated at high speed to increase the data transfer rate, the recording pulse width becomes shorter. For example, if the disc rotation speed is 36
At 00 rpm, the recording pulse width is 45 ns. However, laser on/off driving has rise and fall times, and even if a high-speed switching transistor is used, for example, the limit is about Ions. Therefore, it is difficult to shorten the recording pulse width to less than 20 nS in total for rising and falling pulses.

In reality, consider the margin and set the recording pulse width to a minimum of 2.
If it is 5ns, the recording pulse width that can be varied is from 25ns.
45 ns, the variable pulse width is narrow, and it is difficult to correspond to the doubling of the inner/outer circumferential linear velocity ratio at the innermost circumferential position/fi outer circumferential position (=30 mm/60 mm).

In addition, since the recording power of the laser beam is fixed according to the pulse width of the inner circumference, high power output is required on both the inner and outer circumferences, resulting in problems such as shortened laser life and increased prices, similar to the above point (■). was there.

The present invention solves the problems that the prior art had, such as shortening the lifespan of lasers, increasing prices, and C/H in recording methods (methods using fixed recording power or fixed recording pulse width) that correspond to inner and outer circumferential linear velocities. The purpose of the present invention is to provide an optical information recording/reproducing device that solves problems such as deterioration of the optical information.

(Means for Solving the Problems) In order to solve the above problems, the present invention performs servo control on the disk of laser light emitted from a laser, switches the power of the laser, and illuminates the disk with the laser light. An optical information recording/reproducing device for recording data, which is provided with a laser control drive means for simultaneously switching the recording power and recording pulse width of the laser according to the inner and outer peripheral positions of the disk detected by the reproduction signal from the disk. be.

(Function) According to the present invention, since the optical information recording and reproducing apparatus is configured as described above, when recording information on a disk,
The laser control drive means detects the inner and outer circumferential positions of the disk based on reproduction signals successively output from the disk, and simultaneously switches the recording power and recording pulse width of the laser according to the inner and outer circumferential positions of the disk. For example, the laser control means lowers the recording power and narrows the recording pulse width at the inner circumference of the disk, increases the recording power and widens the recording pulse width at the outer circumference of the disk, and adjusts the recording power and recording pulse width to the linear velocity ratio of the inner and outer circumferences. It works to make it correspond to.

This allows a high C/H signal to be obtained and eliminates the need for a high power laser. Therefore, the above problem can be solved.

(Embodiment) FIG. 1 shows an embodiment of the present invention, and is a block diagram of a configuration of a magneto-optical disk device, which is one of optical information recording and reproducing devices.

In this magneto-optical disk device, an optical pickup 10 is provided near a disk 1 rotated by a spindle motor 2. The optical pickup l○ irradiates a laser beam onto the disk 1 and uses the reflected light to output a detection signal FE for focus servo control and a detection signal TE for tracking servo control, and also reproduces information recorded on the disk 1. It has a function of outputting detection signals PDI and PD2.

This optical pickup ↓0 is the laser 11. Beam splitter 12, 14, objective lens ↓3.1/4 wavelength plate 15,
A polarizing beam splitter 16, a photodetector 17 for outputting a reproduction detection signal PCI, a photodetector ↓8 for outputting a reproduction detection signal PD2, a laser mirror 19, and a two-part photodetector 20, for example, for outputting a detection signal TE for tracking servo control. Cylindrical lens (plano-convex lens) 21. and a two-segment photodetector 22 for outputting a detection signal FE for focus servo control.

The output of the photodetector 17.18 (in principle, the signal reproducing means 30 is connected, and the output of the photodetector 20.2
Servo error signal generating means 40 is connected to the output side of 2.

Based on the reproduction detection signals PDIPD2 respectively output from the photodetectors 1718, the signal reproduction means 30
Signal reproduction processing is performed to create a preformatted signal (hereinafter referred to as I
It has a function of outputting a D signal S30a, a magneto-optical signal 53 b, etc., and is composed of an arithmetic circuit and the like. ID
The signal 530a is a signal obtained by recording signals such as track addresses, sector addresses, etc. in pits on the surface of the disk in advance using concavities and convexities, and then reproducing the signals, and is the reproduction detection signal P.
It is obtained by adding DI and PD2 (=PD 1 + PD2 >). Also, the magneto-optical signal 530b records data by recording the magnetization direction of the recording layer in the disk 1 in the form of pits, and the magnetization is caused by the Kerr effect. direction,
In other words, it is a signal obtained by regenerating "l II, IIQI+", and is the differential signal between the regenerated detection signal PDI and PD2 (=PD1-P
It is reproduced by taking D2>.

The servo error signal generation means 40 generates detection signals FE and TE.
This is a circuit that receives the input signal and generates and amplifies a focus error signal S41 and a tracking error signal S42 for focus servo and tracking servo. The servo error signal generation means 40 includes a differential amplifier 41 that generates a focus error signal S41 from the detection signal FE;
A differential amplifier 42 that generates a tracking error signal S42 from the detection signal TE, an amplifier 43 that amplifies the focus error signal S41, and a tracking error signal S42.
It is composed of an amplifier 44 that amplifies the .

A driving means 60 is connected to the output side of the amplifier 43 via a phase compensation circuit n50 that compensates for phase lag and lead, and a notch filter (narrow band filter) 52 for preventing focus high-order resonance. .

On the other hand, a driving means 60 is connected to the output side of the amplifier 44 via a phase compensation circuit 51.

The driving means 60 includes a focus side driving section 61 that performs voltage/current conversion on the output of the notch filter 52 and outputs a focusing driving current f, and a focus side driving section 61 that performs voltage/current conversion on the output of the phase compensation circuit 51 and outputs a focusing driving current f. It is composed of a tracking side drive section 62 that outputs a drive current It. On the output side of this driving means 60, an optical pickup 10 is provided.
The actuator 70 equipped with the is not connected. The actuator 70 moves the objective lens 13 in the focus direction by means of an objective lens vertical drive coil operated by a focus drive current Jf, and also moves the optical pickup 10 in the radial direction of the microscope 1 by a tracking drive current It. .

Further, the laser 11 is connected to a laser control driving means 80, which is a feature of this embodiment. The laser control driving means 80 has a function of simultaneously switching the recording power and recording pulse width of the laser 11 based on the ID signal 530a from the signal reproducing means 30, depending on the inner and outer peripheral positions of the disk.

This laser control drive means 80 is composed of a control section 81, a modulation/demodulation section 82, and a laser drive section 83. The control unit 81 receives the current track address AD from the modulation/demodulation unit 82.
Based on this, it is determined whether the irradiation position of the laser beam is on the inner or outer circumference of the disk, outputs an inner/outer circumference switching signal S81, and further outputs recording data DA consisting of the input bit string DAB and a write clock φ for modulation processing. It has a function to output.

This control section 81 is composed of a CPU (central processing unit) and the like.

The modulation/demodulation unit 82 modulates the recording data DA from the control unit 81 (e.g., 2-7 modulation/demodulation) to improve the recording density.
Recording signal S8 consisting of channel code bit string DAC
It has a function of outputting the ID signal 530a as well as demodulating the ID signal 530a and outputting the current track address AD, etc., and is composed of a modulation/demodulation circuit and the like.

The laser drive unit 83 has recording power and recording pulse width switched by an inner/outer circumference switching signal S81, and a recording signal S82.
It has a function of outputting a laser drive current 11 corresponding to the current value to cause the laser 11 to emit light.

FIG. 2 is a circuit diagram showing an example of the configuration of the laser driving section 83 shown in FIG.

This laser drive unit 83 selects either the recording signal S82 or the output signal 5100 of the delay element Q1 based on the delay element Q1 that delays the recording signal S82 from the modulation/demodulation unit 82 by about 20 ns, for example, and the inner/outer circumference switching signal S81. and an AND gate (hereinafter referred to as AND gate) Q3 that performs a logical product of the selector Q2 and the recording signal S82 and outputs a recording pulse 5101.

Further, the base and emitter of an NPN transistor TRI, which is a high-speed switching transistor, are connected to the first output of the AND gate Q3 via a base resistor R1 and a bias resistor R2.

The base of a PNP transistor TR2, which is a high-speed switching transistor, is connected to the collector of the transistor TRI via a base resistor R4. A resistor R3 is connected in parallel to the base resistor R4 via a switch SWI that is switched by an inner/outer circumference switching signal S81. The base of the transistor TR2 is connected to the power supply voltage Vcc through a bias resistor R5, and the emitter of the transistor TR2 is connected to the power supply voltage Vcc through a resistor R6. The collector of the transistor TR2 is connected to the laser 11 in the optical pickup 10, and is configured to supply a laser drive current 1 to the laser 11 by turning on and off the transistor TR2.

The servo operation of the magneto-optical disk device configured as described above will be explained below.

First, a laser beam emitted from a laser 11 in an optical pickup 10 passes through a beam splitter 12 and is focused onto a disk 1 by an objective lens 13. The reflected light from the disk l passes through the objective lens 13 and the beam splitter 1.
2, and is further split into beams for servo control and signal detection by a beam splitter 14. The separated beam for signal detection passes through the quarter-wave plate 15 and is separated by the polarizing beam splitter 16 to obtain an ID signal 530a and a magneto-optical signal 530b, which are received by a photodetector 17.18. .

In the signal reproducing means 30, the photodetectors 17 and 18
By adding (=PD1+PD2) the playback detection signals PDi and PD2 respectively output from the ID signal 5
30a and the differential between the reproduction detection signals PDI and PD2 (
=PD1-PD2>, the magneto-optical signal 530b is reproduced.

Furthermore, the beam for servo signals separated by the beam 1 wafer 14 in the optical pickup 10 is transmitted to a laser mirror 19.
, part of the beam is split into two parts for tracking and the rest for focusing.
The light is received by the split type photodetector 20. The focusing beam passes through two cylindrical lenses and is received by a two-part photodetector 22. One photodetector 20 outputs a detection signal TE for tracking servo control, and the other photodetector 22 outputs a detection signal FE for focus servo control.
are outputted and given to differential amplifiers 32 and 31, respectively.

One differential amplifier 41 inputs the detection signal FE and outputs a focus error signal S41, and the other differential amplifier 42 inputs the detection signal TE and outputs a tracking error signal S42. The focus error signal S41 is
After being amplified by the amplifier 43, a phase compensation circuit 50 performs phase delay and lead phase compensation, and the drive unit 61 is passed through a notch filter 52 to prevent focus high-order resonance.
given to. The output of the notch filter 52 is transmitted to the drive unit 6
1, a voltage/current conversion is performed, and a focus drive current If is output from the drive unit 61 and supplied to the actuator 70. The actuator 70 performs focusing control by vertically moving the objective lens 13 using an objective lens vertical drive coil provided therein.

Further, the tracking error signal S42 outputted from the other differential amplifier 42 is amplified by the amplifier 44, then phase compensated by the phase compensation circuit 5, voltage/current converted by the drive unit 62, and the drive unit 62 A tracking drive current rt is output from. The actuator 70 is driven by this tracking drive current It, and tracking control is performed.

As described above, the objective lens 13 is driven to irradiate precisely focused laser light onto the disk I in response to the surface runout of the disk I rotated by the spindle motor 2, and a focusing operation is performed. be exposed. Furthermore, a tracking operation is performed along the track pre-printed (formed) on the disk 1, and a servo is performed so that the focus error signal S41 and the tracking error signal S42 become 0, and the data is recorded. /Playback operation is executed.

Next, the recording operation will be explained with reference to FIGS. 3 to 5.

3 is an explanatory diagram of the recording operation, FIG. 4 is a signal waveform diagram of FIG. 2, and FIG. 5 is a C/N characteristic diagram at the inner and outer peripheral positions of the disk.

First, in the laser control drive means 80 of FIG. 1, the recording data DA from the control section 81 is modulated by the modulation/demodulation section 82 in order to improve the recording density. This modulation operation will be explained using the case of 2 to 7 modem in the -shell as an example.
This will be explained with reference to the table and FIG.

Table 1 2-7 Modulation/Demodulation Conversion As shown in Table 1, the modulation/demodulation section 82 modulates the input bit string DAB from the control section 81 into a channel code bit string DAC by 2-7 modulation.

For example, as shown in FIG. 3, consider a case where recording data DA consisting of an input bit string DAB is sent out from the control section 81. At this time, the control unit 81 also simultaneously sends out the write clock φ as a clock for modulation processing. The modulation/demodulation section 82 converts the input bit string DAB'"10010
", the first 10°" is converted into a channel code bit of "0100" according to Table 1, and the following input bit string "010" is converted into a channel code bit of "100100'°. In this way, the subsequent input bits are similarly converted into channel code bits according to Table 1, and the channel code bit string DAC is sent to the laser drive unit 83 in the form of a recording signal 882.

The laser drive unit 83 outputs a laser drive current 1 according to the input recording signal S82 to cause the laser 11 to emit light. As shown by the symbol INI, the laser drive current 1 is turned on when the bit is "1" and turned off when the bit is 0. Note that a circuit element is connected in parallel with the transistor TR2 in Fig. 2. This circuit element causes a low power current that does not lead to recording to flow through the laser 11.
The laser driving current as shown in the figure (Ll)2 is applied to the laser 11.
It may also be supplied to

Here, fl l of the channel code bit string DAC
I+ laser on time t. . For example, when the disk rotation speed is 3600 rpm, the basic clock (write clock φ×2) is 22.1942 MHz, and becomes (2).

Next, a method of controlling the recording power and recording pulse width in the laser control driving means 80 in order to correspond to the linear speed ratio between the inner and outer circumferences of the disk will be described.

The control unit 81 in FIG. 1 sets the current track address AD to
The signal is read through the signal reproducing means 30 and the modulation/demodulation section 82 to determine whether the laser beam irradiation position is on the inner or outer circumference of the disk, and outputs an inner one-circle switching signal S81 to the laser drive section 83 in accordance with the judgment result.

In the laser drive unit 83 in FIG.
81 switches the selector Q2 and the switch SWI. For example, if the inner/outer circumference switching signal S8↓ is the outer circumference,
The selector Q2 is switched to the recording signal S82 side, and the switch SWI is turned on. When the selector Q2 is switched to the recording signal S82 side, the recording signal S82 is switched to the selector Q
2 to the AND gate Q3, and the recording signal S82 is directly input to the AND gate Q3.

Therefore, a recording pulse 5101 having the same signal as the recording signal S81 is output from the AND gate Q3, and is input to the base resistor R1 of the transistor TRI.

When the "H" level is input to the base resistor R1, the transistor TRI is turned on, and the input terminal of the base resistor R4 of the transistor TR2 becomes the "L" level.

At this time, since the inner/outer circumference switching signal S81 is on the outer circumference side, the switch SWI is turned on, and the base resistance of the transistor TR2 is such that R3 and R4 are in parallel, and the parallel resistance RB2 is as follows. Therefore, the base voltage VB of transistor TR2
2 (outer circumference), the emitter-collector voltage when the transistor TRI is on is Vce1, and the power supply voltage is Vcc.
Then, VB2 (outer circumference) - R5+RB2 (2), transistor TR2 is turned on, and laser drive current 1 flows to laser 11.

On the other hand, when the L'' level of the recording pulse 5101 is input to the base resistance R1 of the transistor TRI, the transistor TRI is turned off, and the base resistance R of the transistor TR2 is turned off.
The input terminal of 4 becomes the power supply voltage VcC. Therefore, the base voltage of the transistor TR2 becomes the power supply voltage Vcc, the transistor TR2 is turned off, and the supply of the laser drive current 1 is stopped.

Next, when the inner/outer circumference switching signal 881 indicates the inner circumference, the selector Q2 in FIG. 2 is switched to the delay element Ql side, and the switch SWI is turned off. Then, the recording signal S8
2 is delayed by, for example, about 20 ns by delay element Q1, and its output signal 5100 is input to AND gate Q3 via selector Q2.

AND game) Q3 outputs the output signal 5 as shown in FIG.
100 and the recording signal S82, outputting a recording pulse 5101 with a recording pulse width reduced by about 20 ns,
given to the base resistor R1.

When the voltage of the base resistor R1 is at the r+Ht+ level, the transistor TRI is turned on, and the input terminal of the base resistor R4 of the transistor TR2 becomes the "L" level.

At this time, since the inner/outer circumference switching signal S81 is on the inner circumference side, the switch SWI is turned off, and the base voltage VB2 (inner circumference) of the transistor TR2 becomes as shown in the following equation.

VB2 (inner circumference>= Therefore, the transistor TR2 is turned on, and the laser drive current ■1 is supplied to the laser 11. The value of this laser drive current ■1 is such that the base voltage VB2 of the transistor TR2 is (2>, (3 ) formula, VB2 (inner circumference)>VB2 (
outer circumference). VB when the laser beam irradiation position is on the inner circumference side of the disk
The second level is large, and the laser drive current 11 is smaller than that at the outer periphery. Therefore, when the laser beam next irradiation position is on the inner circumference side of the disk, the recording power is small, and when it is on the outer circumference side, the recording power is large.

For example, as shown in FIG. 5, the inner/outer circumference switching position of the inner/outer circumference switching signal S81 is determined by the radius r' =
It is desirable to set the switching position to about 38 mm.

As described above, in this embodiment, the laser control drive means 80
Accordingly, the recording power and recording pulse width of the laser 11 are simultaneously switched according to the inner and outer peripheral positions of the disk, so that the following advantages can be obtained.

(i> As a result of experiments using the switching control of the inner and outer circumferences of this embodiment, recording is possible with a recording pulse width of 25 ns and a recording power of 11 mw on the inner circumference of the disk, and with a recording pulse width of 45 ns and a recording power of 13 mw on the outer circumference, and sufficient I got a playback signal.

In contrast, in one of the conventional methods, the recording pulse width fixed and recording power switching method, the recording pulse width is fixed on both the inner and outer circumferences, so the pulse width is 50 ns on the outer circumference, and the recording power is 1.
6 mW was required, and the number of switching stages needed to be four or more.

In addition, with the conventional fixed recording power and recording pulse width switching method, interference between pits occurs on the inner circumference, resulting in a C/N difference of 2 to 3 d.
B has deteriorated.

(ii) In this embodiment, there is little interference between pits even on the inner circumference side of the disk, and a signal with a high C/N can be obtained, and data can be recorded with low recording power on the outer circumference side as well. Therefore, the lifespan of the laser 11 can be extended and the cost can be reduced, and the circuit configuration can also be simplified because the switching control for the inner and outer peripheries can be performed by switching only the two stages of the inner and outer peripheries.

Note that the present invention is not limited to the illustrated embodiment, and various modifications are possible. Examples of such variations are as follows.

(a) The laser drive circuit 83 in the laser control drive means 80 may be configured with a circuit other than that shown in FIG. 2.

(b) In the above embodiment, the case where both focus servo control and tracking servo control are performed and data is recorded on the disk 1 by switching the power of the laser 11 was explained. Disk 1 with only servo control
In an apparatus for recording data on the same, by providing the laser control driving means 80, almost the same advantages as in the above embodiment can be obtained.

(C) Although the above embodiment has been explained using a magneto-optical disk as an example, the present invention is also applicable to a rewritable write-once optical disk device and the like. Furthermore, the optical pickup ■○ shown in FIG.

(d) In the above embodiment, control is performed by switching the inner and outer circumferences into two stages, but it is also possible to perform control by switching the inner and outer circumferences in three stages, four stages, etc., or in a so-called analog manner depending on the position of the inner and outer circumferences. It is also possible to have a configuration in which the recording power and recording pulse width are changed at the same time, and thereby it is expected that the laser life will be longer and the C/N will be improved, etc. compared to the two-stage switching of the inner and outer peripheries of the above embodiment. . When such stepless control is performed over the entire inner and outer periphery of the disk, complication of the circuit configuration can be prevented by executing the laser control driving means under program control of a microcomputer, for example.

(Effects of the Invention) As described in detail above, according to the present invention, the laser control drive means is provided and the recording power and recording pulse width of the laser are simultaneously switched according to the inner and outer circumferential positions of the disk. It is possible to lower the recording power and narrow the recording pulse width on the inner circumference side of the disk, and increase the recording power and widen the recording pulse width on the outer circumference side of the disk, thereby making it possible to correspond to the linear velocity ratio between the inner and outer circumferences. Therefore, there is little interference between pits even on the inner circumference side, and a high C/N signal can be obtained, and data can be recorded with low recording power on the outer circumference side as well. Therefore, the life of the laser can be extended and the cost can be reduced, and since a high-output laser is not required, the circuit scale of the laser drive circuit can be reduced. Furthermore, for example, since the inner and outer circumferential switching control can be performed by switching between the inner and outer circumferential stages in multiple stages, there is an effect that the circuit configuration can be simplified.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a configuration of a magneto-optical disk device showing an embodiment of the present invention, FIG. 2 is a circuit diagram of a laser drive section in FIG. 1, FIG. 3 is an explanatory diagram of recording operation, and FIG. FIG. 2 is a signal waveform diagram, and FIG. 5 is a C/N characteristic diagram at the inner and outer peripheral positions of the disk. 1...disc, 2...spindle motor, 10...optical pickup, 30...
... Signal reproduction means, 40 ... Servo error signal generation means, 60 ... Drive means, 70 ...
- Actuator, 80... Laser control drive means, 81... Control section, 82... Modulation/demodulation section, 83... Laser drive section.

Claims (1)

[Scope of Claims] An optical information recording and reproducing apparatus that performs servo control on a disk with a laser beam emitted from a laser, switches the power of the laser, and records data on the disk with the laser beam. 1. An optical information recording and reproducing apparatus, comprising: a laser control drive means for simultaneously switching the recording power and recording pulse width of the laser according to the inner and outer peripheral positions of the disk detected by reproduction signals from the optical information recording and reproducing apparatus.