JP2000276743A - Method and device for recording and reproduction for magneto-optical disk - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain best data signals during a reproducing and a writing by optimizing the amount of an offset of focus during a focus adjustment. SOLUTION: Every time a focus current is increased, voltages having amplitudes of difference signals corresponding to address information are successively taken in. When address information data in a certain magneto-optical disk 1 are detected at a peak of the signal amplitudes by a prescribed threshold value, a voltage DA1 of a D/A converter 11a is stored during the detection. Similarly, every time a focus current is increased, the voltages of signal amplitudes of the difference signals corresponding to main information are successively taken in. When main information data in the certain magneto- optical disk 1 are detected at a peak of the signal amplitudes by a prescribed threshold value, a voltage DA2 of the detector 11a is stored during the detection. Then, (DA1+DA2)/2 is computed from the two values, outputted and an offset voltage is set by a motor driver/tracking focus control circuit 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording / reproducing method and a recording / reproducing apparatus for a magneto-optical disk for recording, reproducing or erasing information by using optical means such as a laser beam. More specifically, the present invention relates to a method of adjusting a focus position by a focus servo of a recording / reproducing apparatus.

[0002]

2. Description of the Related Art In recent years, with the rapid increase in the amount of processing information due to the development of information processing systems and the increasing density of video discs and digital audio discs due to digitization of video and audio information, optical disc drive devices have recently been developed. There is a need for a more accurate focus servo adjustment method.

Generally, in an information recording / reproducing apparatus as an optical disk apparatus for recording and reproducing data on a magneto-optical disk such as an MD (mini disk) or a PC (phase change type) disk in a predetermined block time unit, At the time of recording,
The output power (hereinafter referred to as "laser power") of a laser that gives a light beam spot to the disk is adjusted in a plurality of steps according to the wattage specified by the disk. Also, at the time of reproduction, the laser power is made variable in a plurality of stages with respect to several types of disks (pre-mastered and MO) having different reflectivities, and the gain is switched to make the reproduction light appropriate. Is performed, the offset is adjusted. In this case, the offset of the tracking error signal or the focus error signal must be accurately adjusted in consideration of the compatibility between another apparatus and the disk.

In particular, in an optical disk apparatus, the optical disk fluctuates in a direction parallel to the laser beam due to surface deflection or the like, so that focus servo control for accurately following the focal position of the laser on the surface of the optical disk is indispensable. It is.

When adjusting the offset in such focus servo control, in a conventional optical disk device, is it necessary to set a focus offset amount so as to maximize the modulation degree of a reproduction signal (Japanese Patent Laid-Open No. 4-85728).
The focus offset amount is set so that the peak of the tracking error signal is maximized (see Japanese Patent Application Laid-Open No. 3-296924).

[0006]

However, in the above-mentioned conventional method, the lens of the actuator of the optical pickup is lowered by about 0.2 mm with respect to the disk by its own weight depending on the direction of the optical disk apparatus with respect to the ground. Therefore, an accurate tracking error signal or focus error signal cannot be obtained, and as a result, there is a problem that the best data signal cannot be obtained at the time of reproduction or writing.

In particular, for a CD or MD disc, the thickness from the disc signal surface to the disc surface is 1.2 mm.
Because the positional relationship between the optical pickup and the disc may vary by about 0.4 mm due to the tolerance of ± 0.1 mm, or due to the runout of the disc or the backlash of the spindle of the spindle motor for fixing the disc, The focus is displaced and the offset of the focus position cannot be adjusted accurately. Furthermore, if the apparatus is to be constructed at low cost, the mechanism will vary widely, and if the NA (numerical aperture) is increased to increase the recording density, the focal length will decrease, and adjustments can be made at more and more constant positions. It will be difficult.

Further, when the laser power is different, there is a problem that the offset including the stray light component cannot be adjusted. For example, when the optical pickup generates the focus error signal FE by the astigmatism method, if the laser power is constant, the tracking error signal F
Signals A and B for detecting E (= A + C-B-D)
The stray light components C and D are constant. However, if the laser power is different, the stray light component also changes, and this change in the stray light component becomes remarkable when the optical pickup uses the hologram method.

[0009] Further, as a big problem that arises as a result, an ADI is actually used in a recording / reproducing apparatus for an optical disk.
When address information is detected using a wobble signal of a guide groove such as a P signal, there is a problem that the signal amplitude or the error rate depends on the focus offset amount depending on the groove shape of the guide groove. This is different from the optimum point of the signal amplitude when the focus offset of the differential signal of the main signal is performed. Therefore, the focus offset learning method of setting the focus offset amount so as to maximize the modulation degree of the reproduction signal of the main information. Then, ADIP
There is a problem that an address error occurs when the characteristic of the signal with respect to the focus offset changes. Also,
In the case of a recording / reproducing apparatus that controls the rotation of a motor based on the frequency of ADIP, there is a problem that a failure such as the motor on which the disk is mounted does not rotate occurs.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems in the prior art, and it is an object of the present invention to optimize the amount of focus offset at the time of focus adjustment and obtain the best data signal at the time of reproduction or writing. An object of the present invention is to provide a recording and reproducing method and a recording and reproducing apparatus for a magnetic disk.

[0011]

In order to achieve the above object, a first recording / reproducing method for a magneto-optical disk according to the present invention comprises a spiral or concentric guide groove or pit having address information. A magneto-optical disk recording / reproducing method, comprising: a disk substrate; and a recording film formed on the disk substrate and capable of recording and reproducing an information signal of main information according to a magnetization direction of a perpendicular magnetization film. At the time of focus control when recording and reproducing information by condensing laser light on a disk, the polarization plane of the reflected light of the condensed laser light is rotated in accordance with the direction of magnetization of the perpendicular magnetization film, and the polarization direction is changed. The first focus offset amount detected by the differential signal at the light receiving unit divided into a plurality of light receiving units in accordance with Using a second focus offset of the signal detected by the differential signal, the first
The reproduction of the address information and the recording / reproduction of the main information are performed by setting a focus offset amount between the focus offset amount of the second and the second focus offset amount.

Further, the second aspect of the magneto-optical disk according to the present invention is as follows.
The recording / reproducing method of (1) includes a disk substrate having a spirally or concentrically formed guide groove or pit having address information, and an information signal of main information formed on the disk substrate, the main information signal being determined by the direction of magnetization of the perpendicular magnetization film. A recording / reproducing method for a magneto-optical disk comprising: a recording film capable of recording / reproducing; and a focus control when performing recording / reproducing of information by condensing a laser beam on the magneto-optical disk; A first focus offset amount detected by a differential signal at a light receiving unit divided into a plurality of portions according to a polarization direction by rotating a polarization plane of the reflected light of the condensed laser light according to a direction of magnetization. And a second focus offset amount in a signal detected by an addition signal in the light receiving unit divided into a plurality of light receiving units, and the first focus offset amount and the second focus offset amount are used. Set the focus offset amount between the focus offset amount and performing recording and reproduction of the reproduction and the main information of the address information.

According to the first or second recording / reproducing method of the present invention, a focus offset amount detected by a differential signal of a main information reproduction signal and a wobble signal of a guide groove such as an ADIP signal are used. When detecting address information or detecting address information by pre-pits, the focus offset amount is detected, and when the focus position for each signal is different, the focus offset that minimizes the bit error rate of each reproduced signal Since the amount can be set, accurate focus control, reproduction of address information at an optimal focus position, and recording and reproduction of main information can be performed.

In the first or second recording / reproducing method of the present invention, it is preferable to use, as the first focus offset amount, a focus offset amount at which the amplitude of the modulated signal of the main information is maximized. According to this preferred example, since the detection is easy, the optimum focus offset amount can be detected in a short time.

In the first or second recording / reproducing method according to the present invention, the first focus offset amount is a focus offset amount that minimizes a jitter of a binarized information signal of a reproduction signal. Is preferred. According to this preferred example, since the change in the jitter value when offsetting is large, the focus offset amount can be accurately detected.

In the first or second recording / reproducing method of the present invention, the error rate of the main information signal demodulated after binarizing the reproduced signal is minimized as the first focus offset amount. It is preferable to use the focus offset amount. According to this preferred example, it is possible to set an optimum focus offset amount in an actual demodulated signal.

In the first recording / reproducing method according to the present invention, it is preferable to use, as the second focus offset amount, a focus offset amount at which the amplitude of the modulated signal of the address information is maximized. According to this preferred example, the focus offset amount can be efficiently detected in a short time.

In the first recording / reproducing method of the present invention, it is preferable to use, as the second focus offset amount, a focus offset amount that minimizes a jitter of a binarized information signal of the reproduced signal. According to this preferred example, the focus offset amount can be detected with high accuracy.

In the first recording / reproducing method of the present invention, the second focus offset amount is a focus offset amount at which the error rate of the address information signal demodulated after binarizing the reproduction signal is minimized. It is preferable to use According to this preferred example, it is possible to set an optimum focus offset amount in an actual use state.

In the first recording / reproducing method according to the present invention, the second focus offset amount is determined from a focus position at which the error rate of the address information signal demodulated after binarizing the reproduction signal starts to increase. It is preferable to use a focus offset amount set by offsetting by a predetermined value in the focus direction. According to this preferred example, it is possible to reduce the measurement time when the optimum offset amount is detected based on the error rate. In this case, it is preferable that the second focus offset amount is 1.0 μm or more.

In the above case, the difference or the addition signal in the rotation direction of the magneto-optical disk is further used to make the second
Is preferably set. According to this preferred example, even when a photodetector divided in the rotation direction is used, the signal reception amount can be detected efficiently.

Further, in the first or second recording / reproducing method of the present invention, the reproduction of the address information and the main reproduction are performed by setting the focus offset to an intermediate value between the first focus offset and the second focus offset. It is preferable to record and reproduce information.

In the first or second recording / reproducing method of the present invention, the setting of the focus offset amount may be
It is preferable to perform this at the time of inserting the magneto-optical disk. According to this preferred example, it is possible to prevent a problem caused by a difference in characteristics between magneto-optical disks.

In the first or second recording / reproducing method of the present invention, the setting of the focus offset amount may be
It is preferably performed at the start of recording of the main information. According to this preferred example, it is possible to prevent a defect at the time of recording the main information.

In the first or second recording / reproducing method according to the present invention, the setting of the focus offset amount may be
It is preferable to perform the process for each predetermined radius or predetermined address in the magneto-optical disk. According to this preferred example, even when the groove shape distribution or the distribution of the characteristics of the address information signal is present in the magneto-optical disk, the main information is obtained by using the optimum focus offset amount at each radial position. Recording and reproduction can be performed.

In the first or second recording / reproducing method of the present invention, the setting of the focus offset amount is
It is preferable to perform the process for each predetermined radius or each predetermined address in the magneto-optical disk and store the set focus offset amount.

In the first or second recording / reproducing method according to the present invention, the setting of the focus offset amount may be
It is preferable to carry out at regular time intervals. According to this preferred example, even when the characteristics of the recording / reproducing device with respect to the focus offset change due to the direction of the recording / reproducing device, the use environment, etc., it is possible to perform recording / reproducing using the optimal focus offset amount. Become.

In the first or second recording / reproducing method according to the present invention, the second focus offset amount is detected when the magneto-optical disk is inserted, and the detected second focus offset amount is stored. Is preferred.

In the first or second recording / reproducing method according to the present invention, it is preferable to detect the focus offset amount by switching the laser power of the laser beam applied to the magneto-optical disk a plurality of times. According to this preferred example, it is possible to detect the optimum focus offset amount with the respective laser powers at the time of recording and at the time of reproduction.

In the first or second recording / reproducing method of the present invention, the focus offset amount is detected by switching the laser power of the laser beam applied to the magneto-optical disk a plurality of times, and the detected focus offset amount is determined. It is preferable to memorize.

In the first or second recording / reproducing method of the present invention, the detection of the first focus offset amount is performed using the maximum amplitude value or the minimum jitter value based on the main information after waveform equalization. Is preferred. According to this preferred example, it is possible to set an optimum focus offset amount according to the setting of the waveform equivalent circuit.

A first configuration of the magneto-optical disk recording / reproducing apparatus according to the present invention comprises: a disk substrate having a spirally or concentrically formed guide groove or pit having address information; What is claimed is: 1. A magneto-optical disc recording / reproducing apparatus comprising a recording film formed and capable of recording / reproducing main information, wherein focus control is performed when recording / reproducing information by condensing a laser beam on said magneto-optical disc. A first focus offset amount detected by a differential signal at a light receiving unit divided into a plurality of light-receiving units in accordance with a polarization direction of main information of the magneto-optical disk; The first focus offset amount and the second focus offset value using a second focus offset amount detected by a difference signal in the light receiving unit divided into two. Set the focus offset between the offset amount and performing recording and reproduction of the reproduction and the main information of the address information.

A second configuration of the magneto-optical disk recording / reproducing apparatus according to the present invention comprises: a disk substrate having a spirally or concentrically formed guide groove or pit having address information; What is claimed is: 1. A magneto-optical disc recording / reproducing apparatus comprising a recording film formed and capable of recording / reproducing main information, wherein focus control is performed when recording / reproducing information by condensing a laser beam on said magneto-optical disc. In some cases, a first focus offset amount detected by a differential signal at a plurality of light receiving units divided according to the polarization direction of the main information of the magneto-optical disk, A focus between the first focus offset and the second focus offset using a second focus offset detected by the addition signal. Set the offset amount and performing recording and reproduction of the reproduction and the main information of the address information.

In the first or second configuration of the recording / reproducing apparatus for a magneto-optical disk according to the present invention, the set offset amount of at least one of the first focus offset amount and the second focus offset amount may be set. It is preferable to have a storage area.

[0035]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described more specifically with reference to embodiments.

FIG. 1 is a block diagram showing an MD recording / reproducing apparatus as a recording / reproducing apparatus for a magneto-optical disk to which the focus offset adjusting method according to the present invention is applied, and FIG. 2 is a block diagram showing a configuration of an optical head part in FIG. FIG. 3 is a block diagram showing the configuration of the preamplifier of FIG.

In FIG. 1, on the disk substrate 1a of the magneto-optical disk 1, there is formed a guide groove 101 consisting of a meandering wobble groove having address information spirally from the inner peripheral side toward the outer peripheral side (ie, from the inner peripheral side). , A track meandering spirally is formed) (FIG. 5).
(See (a)). Further, on the disk substrate 1a, a recording film 1b capable of recording and reproducing an information signal of main information by the direction of magnetization of the perpendicular magnetization film is formed. The optical pickup 2 optically records bibliographic information, audio information, and video information in a predetermined format on the track, and optically reproduces the information recorded on the track. The magneto-optical disk 1 is rotated at a CLV (constant linear velocity) by a spindle motor 3 and a motor driver / tracking / focus control circuit 4 based on a signal reproduced by the optical pickup 2 from the magneto-optical disk 1. The optical pickup 2 includes a superimposing device 5 and a traverse motor 6, and a magnetic field modulation head 7
And work together.

As shown in FIGS. 1 and 2, the optical pickup 2 emits laser light from a laser diode (LD) 16, converts the laser light into parallel light by a collimating lens 17, and passes through a polarizing beam splitter 18. After that, the laser light is focused on the signal surface of the magneto-optical disk 1 by the objective lens 19. Then, the magneto-optical disk 1
The light reflected by rotating the polarization plane according to the state of the signal (direction of magnetization of the perpendicular magnetization film) is reflected by the polarization beam splitter 18, and is reflected by the half mirror 21 as the main information R.
The light is separated into light for detecting the F signal and light for detecting the servo. The light separated on the RF signal side is rotated in the polarization plane by the λ / 4 wavelength plate 22, and then the polarization beam splitter 2
3 separates according to the polarization direction. The light amounts of the respective lights separated by the polarization beam splitter 23 are RF1 and RF1 by photodetectors 24 and 25, respectively.
2, and the signal of the main information is reproduced by the differential signal. The light separated in the servo direction is supplied to a photodetector 26 having a plurality of divided light receiving portions.
Is detected as a focus error signal and a tracking error signal. That is, signals A to A for detecting a focus error signal from the quadrant sensor by the astigmatism method.
D and two signals E and F for detecting two types of tracking error signals by the three-beam method are output (see FIG. 3).

These signals RF1, RF2, AF are:
The signal is amplified by the head amplifier 8 and output to the preamplifier 9 which operates as a detecting / adjusting means. Further, the optical pickup 2 is connected to the head amplifier 8 from the preamplifier 9.
A signal for driving the laser diode 16 is applied.

The preamplifier 9 sends the reproduced EFM signal, ADIP signal, and the like to the EFM modulation / demodulation / error correction / ADIP (address implement groove) / servo circuit 10.
It outputs a focus error signal FEO, a tracking error signal TEO, and the like. The servo circuit of the circuit 10 is constituted by, for example, a DSP (Digital Signal Processor).

At the time of recording, the EFM modulation / demodulation / error correction / ADIP / servo circuit 10 encodes recording data, modulates it into an EFM signal, and outputs it to the magnetic field modulation head 7 via the driver 7a. Also, EFM modulation / demodulation / error correction /
During reproduction, the ADIP / servo circuit 10 demodulates the EFM signal from the preamplifier 9 to perform error correction decoding, and based on the focus error signal FEO and the tracking error signal TEO, the optical pickup 2 moves the track of the magneto-optical disk 1. The optical pickup 2 is controlled via a motor driver / tracking / focus control circuit 4 so that tracking and focusing are performed.

Further, the microcomputer 11 performs a write operation
The optical pickup 2 is moved near the innermost circumference of the magneto-optical disk 1 (T
OC: Table Of Contents and UT
OC: User Table Of Content
Move to s) and read out the necessary ID information.

The microcomputer 11 includes an A / D converter 11a for receiving various signals A to F, FEO, TEO, and the like from the preamplifier 9, and a laser diode 16 in the optical pickup 2.
For controlling the output power of the laser diode 16 by driving, for example, a signal corresponding to a 12-bit PWM signal.
An M section 11b, a RAM 11c for a work area and the like, a ROM 11d for a program and the like, and a CPU 11e for performing control as described later, etc.
a to 11e are connected via a bus. Also, RA
M11c has an area for storing measurement data and the like used by the CPU 11e to perform offset adjustment described later.

The PWM signal from the PWM section 11b is converted into a DC voltage by a low-pass filter (LPF) 12, and the DC voltage is applied to the laser diode 1 in the optical pickup 2 via a preamplifier 9 and a head amplifier 8.
6 is driven. In FIG. 1, reference numeral 13 denotes a focus offset adjustment circuit.

Next, the preamplifier 9 will be described in detail with reference to FIGS. First, each of the balances output from the microcomputer 11 via the D / A converter 35 to the signals A to D for detecting the focus error signal FE of the four-division sensor by the astigmatism method in the optical pickup 2. The adjustment values are added by the adders 31A to 31D to adjust the balance of the signals A to D and to perform I / V conversion. Next, the adders 31A to 31D
Are applied to the computing unit 32F, and a focus error signal is generated based on the computing equation (A + CBD). Next, the focus error signal and the offset adjustment value also output from the microcomputer 11 via the D / A converter 35 are added by the adder 33F to adjust the offset, and the focus error signal FE
Is output as

Also, signals E and F for detecting the tracking error signal TE by the three-beam method in the optical pickup 2 are provided with respective balance adjustment values output from the microcomputer 11 via the D / A converter 35, respectively. Are added by the adders 31E and 31F to adjust the balance between the signals E and F, and I / V converted. Next, the output signals E and F of the adders 31E and 31F are applied to the subtractor 32T, and a tracking error signal is generated based on the arithmetic expression (EF). Next, the tracking error signal and the offset adjustment value output from the microcomputer 11 via the D / A converter 35 are added by the adder 33T to adjust the offset, and output as the tracking error signal TE.

The output signals A to F of the adders 31A to 31F, the focus error signal FE, and the eight signals of the tracking error signal TE are converted to digital values by the A / D converter 11a, 11, the balance and offset of the focus error signal FE and the tracking error signal TE are adjusted, and the respective adjustment values are added via the D / A converter 35 to the adder 31A.
To 31F, 33F, and 33T.

Next, the focus offset adjusting method of the present invention will be described in more detail with reference to FIGS.

<First Embodiment> FIG. 4 is a flow chart showing a focus offset adjusting method according to a first embodiment of the present invention.

First, the optical pickup 2 is placed at the initial position, and the rotation of the magneto-optical disk 1 is started (111). Then, the focus position is set by setting a voltage value corresponding to the set voltage of the focus offset based on a table (hereinafter, referred to as a “ROM table”) written in the ROM 11d in advance (112).
When the setting of the focus position is completed (113), laser light is emitted from the laser diode 16 (114), and rotation control is performed on the magneto-optical disk 1 in a state where the focus and tracking are applied (115). Here, each voltage of the focus error signal FE and the tracking error signal TE is measured, and these voltages are output to the D / A converter 35. Thereby, focus control is started (11).
6). That is, in the focus offset adjusting circuit 13, when the magneto-optical disk 1 is inserted, the focus servo loop is closed, and while the offset value to the focus servo based on the ROM table is changed, the focus detector is divided into a plurality of parts of the photodetector 26. The light is added in the tangential direction by the light receiving section, and
The focus offset value at which the modulated signal of the light detected by the difference in the radial direction becomes the maximum is measured. And
When the focus control based on the difference signal of the address information is completed (117), the measured focus offset value is stored in a predetermined area of the RAM 11c (11).
8). The main information signal is detected by the photo detectors 24 and 25 with respect to the focus offset value. Here, when detecting the signal of the main information, the reproduced signal of the main information reproduced by the differential signal in which the low frequency component due to the birefringence of the substrate or the surface deflection of the disk is removed by the high-pass filter in which the low frequency is attenuated Is measured. When the focus control based on the main information differential signal is completed (119), the measured peak value is stored in a predetermined area of the RAM 11c as a focus offset value based on the main information differential signal (12).
0). Next, an intermediate value between the two offset values in the focus direction is output as a focus offset value. As a result, an optimum focus position is obtained (12
1).

In this embodiment, the focus offset voltage is increased by the D / A converter 35 to increase the focus current, and each time the focus current increases, the signal amplitude of the difference signal corresponding to the address information is increased. Voltage is taken in sequentially. When the data of the address information in the magneto-optical disk 1, which is the peak of the signal amplitude, is detected at a predetermined threshold, the voltage DA1 of the D / A converter 35 at the time of the detection is stored. Similarly, each time the focus current increases, the voltage of the signal amplitude of the differential signal according to the main information is sequentially taken into the A / D converter 11a. When the main information data in the magneto-optical disk 1 at the peak of the signal amplitude is detected at a predetermined threshold value, the voltage DA2 of the D / A converter 35 at the time of the detection is stored. Next, an arithmetic operation of (DA1 + DA2) / 2 is performed from these two values, and this is output. The motor driver / tracking / focus control circuit 4 sets an offset voltage. This allows
The focus position for focusing on the signal surface of the magneto-optical disk 1 is adjusted.

When the focus offset adjustment is completed as described above (122), reproduction of address information and recording / reproduction of main information are performed (123).

FIG. 7A is a characteristic diagram showing the relationship between the focus offset amount and the RF signal amplitude amount of the main information, and FIG.
FIG. 7A is a characteristic diagram illustrating a relationship between a focus offset amount and a wobble amplitude amount of address information when a groove width is changed.

As shown in FIG. 7A, the focus position at which the signal amplitude of the differential signal according to the main information is maximum is −
0.3 μm. On the other hand, as shown in FIG. 8A, the dependence of the signal amplitude of the difference signal on the focus offset amount according to the address information changes with the change in the groove shape. That is, when the groove width increases, the focus offset amount at which the signal amplitude of the difference signal corresponding to the address information reaches a peak greatly changes in the + direction, and when the groove width is 1.0 μm or more, the focus offset amount becomes +.
It becomes 0.5 μm or more.

As can be seen from the above characteristics, according to the present embodiment, the difference between the peak value of the signal amplitude of the differential signal according to the main information and the peak value of the signal amplitude of the differential signal according to the address information is obtained. By setting the focus offset value, the focus offset value is optimized in the reproduction of the address information signal and the recording and reproduction of the main information signal, and the allowable range of the focus offset including both of them is maximized. it can.

In the present embodiment, when performing focus control based on the difference signal of the address information, first, addition is performed in the tangential direction by a plurality of divided light receiving portions of the photodetector 26 ( 3 in FIG.
2A), and the difference may be obtained in the tangential direction.

Next, a description will be given of a focus offset adjusting method according to the second to fifth embodiments of the present invention.

<Second Embodiment> In this embodiment, when the magneto-optical disk 1 is inserted, the focus offset is adjusted as follows. That is, the focus offset voltage initially set in the drive is set to D
By increasing the current by the / A converter 35, the focus current is increased, and the reproduction signal of the address information is binarized every time the focus current increases, and the noise jitter when the focus offset is changed is sequentially taken in. Then, when a reproduced signal of the address information is detected at a predetermined threshold value that minimizes the jitter as shown in FIG. 8C, the voltage DA1 of the D / A converter 35 at the time of this detection is stored. Here, when the groove depth is small, as shown in FIG.
The dependence of IP jitter on focus offset changes.

Similarly, each time the focus current increases, the reproduced signal of the main information is binarized, and the noise jitter when the focus offset is changed is sequentially taken in. When the reproduction signal of the main information is detected at a predetermined threshold at which the jitter is minimized as shown in FIG.
The voltage DA2 of the / A converter 35 is stored.

Next, DA2 + α (D
A2-DA1) / 2 is calculated and output, and the motor driver / tracking / focus control circuit 4 sets the focus offset voltage. Thus, the focus position for focusing on the signal surface of the magneto-optical disk 1 is adjusted, and the reproduction of the address information and the recording and reproduction of the main information are performed. Here, α may be set to a constant as an initial value of the drive.

Note that, as shown in FIG.
If it deviates from that, the shape of the light spot becomes elliptical and the jitter value changes greatly. Therefore, by measuring the jitter value while setting the focus offset current, a more accurate focus offset amount can be set.

<Third Embodiment> In this embodiment, when the magneto-optical disk 1 is inserted, the focus offset is adjusted as follows. That is, the focus offset voltage initially set in the drive is set to D
The focus current is increased by the / A converter 35, and the reproduction signal of the address information is binarized each time the focus current increases. The offset amount at which the rate starts increasing is detected. In this case, as shown in FIG. 8D, the increase in the error rate starts only when the focus is offset in one direction. This is because, as shown in FIG. 6, since the major axis direction of the ellipse is different depending on the direction shifted from the focal point position 201, the error rate sharply increases when the major axis direction expands in the radial direction. is there. Therefore, the amount offset by +1 μm from the start of the error rate increase is stored as the voltage DA1 of the D / A converter 35.

Similarly, every time the focus current increases, the reproduction signal of the main information is binarized, and then the block error rate of the signal subjected to the EFM demodulation is sequentially taken in to detect the offset amount at which the error rate starts to increase. I do. In this case, as shown in FIG. 7E, the error rate starts increasing regardless of the focus offset in either direction, so that the D / A at the time of detecting the offset amount at the center is used.
It is stored as the voltage DA2 of the converter 35.

Then, from these two values, (DA1 + DA
2) / 2 is calculated and output, and the motor driver / tracking / focus control circuit 4 sets a focus offset voltage. Thus, the focus position for focusing on the signal surface of the magneto-optical disk 1 is adjusted, and the reproduction of the address information and the recording and reproduction of the main information are performed.

<Fourth Embodiment> In this embodiment, when the magneto-optical disk 1 is inserted, the focus offset is adjusted as follows. That is, the focus offset voltage initially set in the drive is set to D
The focus current is increased by the / A converter 35, and the read signal of the address information is binarized every time the focus current increases, and the noise jitter in the window is sequentially taken in. Then, FIG.
When the reproduction signal of the address information is detected at a predetermined threshold value which minimizes the jitter as shown in (1), the voltage DA1 (r1) of the D / A converter 35 at the time of this detection is stored. Further, the radial offset in the magneto-optical disk 1 is changed, and the focus offset amount at which the jitter is similarly minimized at different locations is stored as a table such as a voltage DA1 (r2, r3,...).

When recording and reproducing the main information signal, the reference signal recorded on the magneto-optical disk 1 or the already recorded main information signal is reproduced while changing the focus offset amount. Then, the reproduced signal of the main information is binarized after waveform equalization, and the noise jitter when the focus offset is changed is sequentially taken in. When the reproduction signal of the main information is detected at a predetermined threshold value that minimizes the jitter, the voltage DA2 of the D / A converter 35 at the time of the detection is stored. In this case, the signal of the main information is measured as the jitter value of the reproduced signal after waveform equalization as shown in FIG.

Next, the focus offset voltage DA1 (r1, r2,...) At which the jitter of the address information of the table stored when the magneto-optical disk 1 is inserted is minimized.
And the focus offset voltage DA2 that minimizes the jitter detected from the main information, and sets the focus offset amount between them at each measurement position. Thus, the focus position for focusing on the signal surface of the magneto-optical disk 1 is adjusted, and the reproduction of the address information and the recording and reproduction of the main information are performed.

<Fifth Embodiment> In the present embodiment, it is assumed that the initial position is unknown at the time of insertion of the magneto-optical disk 1, so that the focus current is gradually increased and the tracking error signal TE is increased. Are sequentially taken in. Then, in order to apply servo at the center of the S curve of the focus error signal FE, the focus servo is turned on when the data recording surface is detected at a predetermined threshold.

In order to set the focus offset amount, the focus offset amount is changed while reproducing the address information, and the address information at the light receiving portion of the photodetector 26 divided into a plurality in the radial direction of the magneto-optical disk 1 is obtained. D / A converter 35 that maximizes the degree of signal modulation
Is detected and stored.

When recording the main information signal,
A D / A converter that records a reference signal or a data signal for test recording on the magneto-optical disk 1 in advance, reproduces the signal while changing the focus offset amount, and reproduces a signal with the maximum modulation degree of the reproduced signal. The voltage DA2 of 35 is detected and stored. A method may be used in which test recording and reproduction are performed while changing the focus offset amount, and the offset amount at which the amplitude of the reproduction signal becomes maximum is detected.

Then, from these two values, (DA1 + DA
2) The operation of / 2 is performed, and this is output, and set as a focus offset voltage by the motor driver / tracking / focus control circuit 4.

In the case where only the main information signal is reproduced,
The signal of the main information may be reproduced by setting the focus offset amount by the stored offset voltage DA1.

As described above, according to the first to fifth embodiments, the focus offset amount obtained from the address information and the focus offset amount obtained from the main information are used to determine the difference between the two focus offset amounts. Since the focus offset is adjusted by setting the focus offset amount, an accurate focus position can be obtained. As a result, the best data signal can be obtained when reproducing the address information and when reproducing or writing the main information.

<Sixth Embodiment> Next, a sixth embodiment of the present invention will be described.

At the time of reproducing the main information, an offset amount with respect to the focus recorded in the ROM area is set in advance, or when the magneto-optical disk 1 is inserted, the offset with respect to the focus obtained from the reproduction signal of the address information and the main information is detected. Then, the main information is reproduced by setting the focus offset amount during that period.

At the start of recording of the main information, a reference signal previously recorded on the magneto-optical disk 1 for adjusting the focus offset of the main information is used. The focus offset amount at which the amplitude becomes maximum is detected. Similarly, while changing the focus offset amount, the focus offset amount that maximizes the signal amplitude for the address information is detected. Then, the focus offset amount is set to an intermediate value between the focus offset amount obtained from the main information and the focus offset amount obtained from the address information, and recording of the main information is started.

In this embodiment, the reference signal recorded in advance on the magneto-optical disk 1 is used for detecting a signal obtained by changing the focus offset amount of the main information.
An information signal that has already been recorded or an information signal that has been trial-recorded for offset adjustment may be used.

When adjusting the focus offset, the offset amount may be detected within a predetermined time or within a predetermined range in the radial direction, and an averaged value may be used as the set value of the focus offset.

<Seventh Embodiment> Next, a seventh embodiment of the present invention will be described.

By the way, when the focus is offset,
The shape of the light spot is, as shown in FIG.
In the case of 01, the shape is almost circular. In particular, the address information formed as a wobble groove is easily affected by an adjacent track due to the change in the shape of the light spot, and when the major axis of the elliptical light spot spreads in the radial direction of the magneto-optical disk 1. , The error rate increases sharply.
As shown in FIGS. 8A and 8B, the dependence of the wobble amplitude amount on the focus offset amount greatly changes depending on the groove shape such as the groove width or the groove depth. Therefore, when the groove shape is uniform, the focus offset amount that minimizes the jitter or error rate of the address signal is almost constant in the magneto-optical disk 1.

In this embodiment, the operation of setting the focus offset when the magneto-optical disk 1 is inserted is the same as in the first to fifth embodiments.

In this embodiment, the optical pickup 2 is controlled so as to reciprocate within a range where the focus is not deviated by a triangular waveform focus current which increases linearly and then decreases linearly, and signals A to F, Although the FE or the circuit is not shown, A + D, B + C, etc. are taken into the A / D converter 11a for several to several tens of positions within a uniform range of the focus offset movement range at a constant sampling cycle and measured.

Then, the D / A converter 35 changes the linear current with respect to the focus offset amount, for example, to 0, 20, 40, 60, 80, 100, 120, 1
Output like 10 places of 40, 160, 180 mA,
A / D conversion is performed on the wobble amplitude amount in a short time at each current value position, and A1, A2, A3, A4,...
Is stored as a block in a predetermined area of the RAM 11c.

Next, one block having the smallest wobble amplitude is compared and extracted from each of the stored blocks, and this is set as a value of an offset amount with respect to a target focus by the address information signal. Then, the offset amount is stored in a predetermined area of the RAM 11c as a focus offset amount optimal for the address information of the magneto-optical disk 1. Corresponding to the value of this offset amount,
The value is set so as to be output as the voltage value of the D / A converter 35 determined by the ROM table so that the value becomes a predetermined reference voltage.

Further, in the RAM area in the magneto-optical disk 1 on which the main information is recorded, the main information is recorded and reproduced first by actually inserting the magneto-optical disk 1 or in the sixth embodiment. Similarly, when recording of the main information is newly started, similarly to the case of setting the focus offset amount of the address information, the light is increased by a triangular waveform focus current which increases linearly and then linearly decreases. The pickup 2 is controlled so as to reciprocate in a range where the focus is not deviated, and detects a focus offset amount at which the modulation degree of the reproduction signal of the main information is maximum.

The focus offset voltage is set to a value between the focus offset amount at which the wobble amplitude is minimized when reproducing the address signal set when the magneto-optical disk 1 is inserted and the focus offset amount obtained from the main information. And start recording. If only the main information is reproduced, the focus offset voltage set before the operation is maintained.

Therefore, according to this embodiment, the focus offset amount obtained from the address information can be changed in a shorter time than in the sixth embodiment.
Adjustment processing and adjustment time can be reduced.

Further, when recording and reproducing compressed main information such as an MD, the focus adjustment of the main information can be performed within the processing time for modulation and demodulation of the information. It is possible to perform processing such as modulation and demodulation of information without performing the above. Further, the magneto-optical disk 1
Since the focus offset amount can be obtained by the optimal adjustment for each time, the best data signal can be obtained at the time of reproduction or writing.

<Eighth Embodiment> Next, an eighth embodiment of the present invention will be described.

In this embodiment, similarly to the seventh embodiment, when the magneto-optical disk 1 is inserted, the focus current having a triangular waveform that increases linearly and then decreases linearly causes the optical pickup 2 to move. Control is performed so as to reciprocate in a range where the focus is not deviated, and signals A to F, FE or a circuit during this period are not shown. A few to several tens of points are taken into the A / D converter 11a and measured.

At this time, as shown in FIGS. 8A and 8B, the dependence of the wobble amplitude on the focus offset greatly changes depending on the groove shape such as the groove width or groove depth. I have. Therefore, when the groove shape is uniform, the offset amount at which the jitter or error rate of the address signal is minimized is substantially constant in the magneto-optical disk 1, but the groove shape is distributed in the magneto-optical disk 1. In such a case, the optimum focus offset amount differs depending on the location of the magneto-optical disk 1.

Therefore, in this embodiment, the optical pickup 2 is moved in the radial direction of the magneto-optical disk 1 to detect the focus offset amount at which the jitter of the reproduced signal due to the address information is minimized, and the inserted light is detected. The information on the radial position, which is a characteristic unique to the magnetic disk 1, and a table of the value of the focus offset voltage are stored in a predetermined area of the RAM 11c. At this time, the method of comparing and extracting the focus offset amount that minimizes the jitter of the address information signal is the same as in the case of the seventh embodiment.

When the main information is recorded / reproduced first by actually inserting the magneto-optical disk 1 in the RAM area in the magneto-optical disk 1 where the main information is recorded, or
As in the case of the seventh embodiment, when recording of new main information is started, similarly to the case of setting the focus offset amount of the address information described above, a triangle that increases linearly and then decreases linearly is used. The optical pickup 2 is controlled to reciprocate in a range where the focus is not deviated by the waveform focus current, and a focus offset amount at which the modulation degree of the reproduction signal of the main information is maximized is detected.

When the magneto-optical disk 1 is inserted, RA
The focus offset amount at which the jitter of the address information signal at the radial position corresponding to the address where the main information of the table stored in the predetermined area of M11c is to be recorded is minimized, the focus offset amount obtained from the main information, The recording is started by setting the focus offset voltage to an intermediate value between. When only the main information is reproduced, the focus offset amount may be set using the focus offset amount of the main information set before the operation and the focus offset amount at the address to be reproduced. It is possible.

Therefore, according to the present embodiment, even when the groove shape distribution or the distribution of the characteristics of the address information signal is present in the magneto-optical disk 1, the optimum focus offset amount at each radial position is obtained. The main information can be recorded / reproduced by using.

The table of the focus offset amount which minimizes the jitter of the reproduction signal due to the radial position of the magneto-optical disk 1 and the address information is a table of the offset amount with respect to the address of the magneto-optical disk 1, By performing the optimal adjustment for each of the predetermined positions, an optimal focus offset amount can be obtained,
As a result, the best data signal can be obtained at the time of reproduction or writing.

<Ninth Embodiment> Next, a ninth embodiment of the present invention will be described.

When the recording / reproducing apparatus for a magneto-optical disk is used for portable use, the direction of the recording / reproducing apparatus, the use environment, and the like change. The positional relationship changes, which may cause a problem.

Therefore, in the present embodiment,
As in the fifth embodiment, when the magneto-optical disk 1 is inserted,
The focus offset amount at which the signal amplitude of the address information signal becomes maximum when the focus is offset and the focus offset amount at which the signal amplitude of the main information signal becomes maximum are detected. Set. When the main information signal is continuously reproduced, the same focus offset amount adjustment as described above is performed every 30 minutes. When the main information signal is continuously recorded, every 15 minutes. The same adjustment of the focus offset amount is performed. By adjusting the recording / reproducing apparatus at a fixed time interval in this manner, even if the characteristics of the recording / reproducing apparatus with respect to the focus offset change due to the direction of the recording / reproducing apparatus, the use environment, etc., the recording / reproducing is performed using the optimal focus offset amount. It is possible to do.

In this embodiment, as in the seventh and eighth embodiments, the focus offset amount is stored in the address information when the magneto-optical disk 1 is inserted, and the focus offset amount is stored in the main information at fixed time intervals. A configuration in which only the focus offset amount is detected and the offset amount is set may be used. The time interval for adjusting the focus offset amount can be arbitrarily set according to the use environment or the characteristics of the recording / reproducing apparatus with respect to the environment.

<Tenth Embodiment> Next, the tenth embodiment of the present invention will be described.
An example will be described.

The optical pickup 2 in the magneto-optical disk recording / reproducing apparatus may include a stray light component depending on the set laser power, and the laser power changes depending on the temperature characteristics. In particular, when reproducing the ROM area and the RAM area in the magneto-optical disk 1 by changing the reproducing power,
The power of the laser light emitted from the objective lens 19 of the optical pickup 2 changes in a range from 0.2 mW to 5 mW or more. At this time, a problem may occur in the focus characteristics depending on the laser power.

Therefore, in the present embodiment, the above-described first to first embodiments will be described.
As in the fifth embodiment, when the magneto-optical disk 1 is inserted,
The laser power is set to the reproduction power of 0.2 mW, and the address information signal when the focus is offset is 2
A focus offset amount at which the jitter when binarized is minimized and a focus offset amount at which the jitter is binarized when the main information is binarized are detected, and the focus offset amount at the time of recording / reproducing is set between them. . Next, the laser power is set to 5 mW of the recording power, and the characteristics of the address information with respect to the focus offset and the characteristics of the main information with respect to the focus offset are detected by the same method,
Adjust the focus offset. Then, the set amount of the offset for each detected power is calculated as RA
It is stored as a table in a predetermined area of M11c.

In the above adjustment operation, the focus offset amount is set when the magneto-optical disk 1 is inserted, and stored as a table of the offset amount with respect to the laser power. The offset amount with respect to the focus is adjusted each time the laser power changes. May be.

Further, in the present embodiment, similarly to the seventh and eighth embodiments, the address information when the laser power is changed when the magneto-optical disk 1 is inserted using the triangular waveform focus current is used. The configuration may be such that the focus offset amount is stored, and only the focus offset amount for the main information is detected each time the laser power is changed, and the offset amount is set.

In the above adjustment operation, the case where the laser power at the time of reproduction is constant has been described as an example. However, in the case of MD, 0.25 mW during reproduction of the ROM area in the disk and reproduction of the RAM area. At the time of recording, the form of the offset may change each time the laser power changes, such as 0.5 mW and 5 mW, respectively. Therefore, the offset may be adjusted each time the laser power changes.

In this embodiment, the laser power is set to 0.25 mW (at the time of reproduction in the TOC area), 0.5 mW
(When reproducing the data area) Thus, the offset can be adjusted without setting the laser power (for example, 5 mW or the like) at the time of recording in the RAM area in the disk. Therefore, the normal laser power is 5 m
There is no danger of erasing necessary data as in the case of adjusting offset by setting to W,
There is also an advantage that the measurement is completed in a short time. Also,
Although a method using a table has been described as an example, the method may be simplified, or may be switched to an arithmetic expression instead.

In the first to tenth embodiments, the case where the focus offset amount of the address information signal is adjusted by detecting the ADIP signal (= A + DBC) has been described as an example. But A to F, RF
The focus offset amount may be adjusted when an address information signal using a signal obtained by adding a combination of RF signals and RF2 or a signal in which a combination is changed such as a difference signal in the tracking direction is used.

<Eleventh Embodiment> Next, an eleventh embodiment of the present invention for adjusting the focus offset amount of an address information signal by using an addition signal will be described.

FIG. 5B is a sectional view of the pit portion of the address information and a diagram showing the signal amplitude of the total reflection light amount.
As shown in FIG. 5B, on the disk substrate of the magneto-optical disk, pits 102 having at least address information are formed at the center of the track in a spiral shape from the inner side to the outer side. Regarding the address information based on the pits, the relationship between the focus offset and the signal amount is detected by the same method as the method of detecting the focus offset amount of the address information signal based on the difference signal in FIG.

In this embodiment, when the magneto-optical disk 1 is inserted, the optical pickup 2 reciprocates in a range where the focus is not deviated by a triangular waveform focus current which increases linearly and then decreases linearly. Although the signal during this period is not shown, the addition signal of A + B + C + D is converted to A by several to several tens of points at a uniform position in the moving range of the focus offset at a constant sampling cycle.
It is taken into the / D converter 11a and measured.

At this time, as shown in FIG. 5 (b), the signal amplitude of the address information signal, that is, the total reflection light amount signal changes greatly depending on the shape of the pit 102 and the position of the laser beam. In addition, since it has a dependency on the focus offset, it differs from the maximum value of the signal amplitude of the differential signal depending on the polarization direction of the main information.

Here, the signal amplitude of the address information signal is
If the shape of the pits 102 is uniform, it becomes almost constant in the magneto-optical disk 1. Therefore, it is only necessary to adjust the focus offset when the magneto-optical disk 1 is inserted. When the distribution is within the range, the optimum focus offset amount for the address information signal differs depending on the location of the magneto-optical disk 1. In this case, the optical pickup 2 is moved in the radial direction of the magneto-optical disk 1 to detect the focus offset amount at which the jitter of the reproduction signal due to the address information is minimized. It is stored in a predetermined area of the RAM 11c as a table of information on the radial position and the value of the focus offset voltage, which are characteristics.

When the main information is actually recorded and reproduced by inserting the magneto-optical disk 1, the main information is increased in a straight line and then increased in a straight line, as in the case of setting the focus offset amount of the address information. The optical pickup 2 is controlled so as to reciprocate in a range in which the focus is not deviated by a focus current having a triangular waveform decreasing like a triangle, and detects a focus offset amount at which the modulation degree of the reproduction signal of the main information is maximized.

When the magneto-optical disk 1 is inserted, the RA
The focus offset amount at which the jitter of the address information signal at the radial position corresponding to the address where the main information of the table stored in the predetermined area of M11c is to be recorded is minimized, the focus offset amount obtained from the main information, The recording is started by setting the focus offset voltage to an intermediate value between. When only the main information is reproduced, the focus offset amount may be set using the focus offset amount of the main information set before the operation and the focus offset amount at the address to be reproduced. It is possible.

The table of the focus offset amount that minimizes the jitter of the reproduction signal due to the radial position of the magneto-optical disk 1 and the address information is a table of the offset amount with respect to the address of the magneto-optical disk 1, By performing the optimal adjustment for each of the predetermined positions, an optimal focus offset amount can be obtained,
As a result, the best data signal can be obtained at the time of reproduction or writing.

The offset adjustment may be performed by adjusting the offset while changing the offset amount instead of using the ROM table.
Instead of using the converter 35, the PWM signal may be converted into a DC voltage and applied.

In this embodiment, the case where the pit 102 is formed at the center of the guide groove or track has been described as an example. However, a wobble in which pits are arranged between tracks without using a guide groove is described. A configuration using the pit and the address pit at the center of the track, or a configuration using at least one of the guide groove and the pit and having address information may be used.

Although the above embodiment has been described using an infinite system optical head, even if a finite system optical head having a configuration excluding the collimator lens 17 in FIG. 2 is used, An equivalent effect can be obtained.

Further, in the above embodiment, FIG.
The method of adjusting the focus offset when a magneto-optical disk is inserted or at the time of recording / reproducing is described as shown in the flowchart of FIG. 7. However, the same effect can be obtained by using the method as an adjusting method at the time of adjusting the assembly of the recording / reproducing apparatus.

Further, in the above-described embodiment, the description has been given by taking as an example the disk substrate on which the guide grooves 101 or pits 102 formed of meandering wobble grooves having address information in a spiral shape are formed. Are the same effects can be obtained even when the disk substrate is a concentric disk substrate.

Further, in the above-described embodiment, the distributed type having the address information on the entire surface of the disk substrate has been described as an example, but the centralized information having the address information only on a part of the track for recording the main information is described. Even in the case of the addressing method of the type, the same effect can be obtained by using the method for adjusting the characteristic with respect to the offset of the address information signal of the present invention.

[0123]

As described above, according to the present invention,
Focus offset when detecting address information by using a focus offset amount detected by a differential signal of a reproduction signal of main information and a wobble signal of a guide groove such as an ADIP signal, or detecting address information by prepits When the offset amount is detected and the focus position for each signal is different, it is possible to set the focus offset amount that minimizes the bit error rate of each reproduction signal, so that accurate focus control and optimal Reproduction of the address information at the focus position and recording and reproduction of the main information become possible.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an MD recording / reproducing apparatus as a magneto-optical disk recording / reproducing apparatus to which a focus offset adjusting method according to an embodiment of the present invention is applied.

FIG. 2 is a block diagram showing a configuration of the optical head of FIG. 1;

FIG. 3 is a block diagram showing a configuration of a preamplifier in FIG. 1;

FIG. 4 is a flowchart illustrating a focus offset adjustment method according to the first embodiment of the present invention.

FIG. 5A is an explanatory diagram showing a shape of an address portion formed by a guide groove according to an embodiment of the present invention; and FIG. 5B is an explanatory diagram showing a shape of an address portion formed by a pit according to the embodiment of the present invention.

FIG. 6 is a diagram illustrating a shape of a light spot when focus offset is performed according to an embodiment of the present invention.

FIG. 7A is a characteristic diagram illustrating a relationship between a focus offset amount and an RF signal amplitude amount of main information according to an embodiment of the present invention; and FIG. 7B is a characteristic diagram illustrating a focus offset amount and main information according to an embodiment of the present invention. Characteristic diagram showing relationship with signal carrier level (c) Characteristic diagram showing relationship between focus offset amount and jitter of EFM signal of main information in one embodiment of the present invention (d) Embodiment of the present invention FIG. 4 is a characteristic diagram showing the relationship between the focus offset amount and the jitter of the EFM signal after waveform equalization in FIG. 5 (e) is a characteristic diagram showing the relationship between the focus offset amount and the block error rate of the demodulated EFM signal in one embodiment of the present invention.

8A is a characteristic diagram showing a relationship between a focus offset amount and a wobble amplitude amount of address information when a groove width is changed according to an embodiment of the present invention; FIG. 7C is a characteristic diagram showing the relationship between the focus offset amount when the groove depth is changed and the wobble amplitude amount of the address information in (c). The focus offset amount when the groove shape is changed according to an embodiment of the present invention. Characteristic diagram showing relationship between ADIP signal and jitter (d) Characteristic diagram showing relationship between focus offset amount and error rate of ADIP signal when groove shape is changed in one embodiment of the present invention

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Magneto-optical disk 1a Disk substrate 1b Recording film 2 Optical pickup 16 Laser diode 24, 25, 26 Photodetector 35 D / A converter 101 Guide groove 102 Pit

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5D075 AA03 CC12 CC24 CD10 EE03 5D118 AA18 BA01 BB02 BB06 BF02 BF03 CA11 CA13 CB01 CB03 CD02 CD03 CD08 CD11 DC03

Claims (24)

[Claims] 1. A disk substrate having a spirally or concentrically formed guide groove or pit having address information, and an information signal of main information formed on the disk substrate, the information signal of main information being recorded by the direction of magnetization of a perpendicular magnetization film. A recording / reproducing method for a magneto-optical disc comprising a reproducible recording film, wherein a laser beam is condensed on the magneto-optical disc to perform recording and reproduction of information; A first focus offset amount detected by a differential signal at a light receiving unit divided into a plurality of portions according to the polarization direction by rotating the polarization plane of the reflected light of the condensed laser light according to the direction of the laser beam. Using the second focus offset amount detected by the difference signal at the light receiving unit divided into a plurality of parts in the radial direction of the magneto-optical disk, and A method for recording / reproducing a magneto-optical disk, wherein the reproduction of the address information and the recording / reproduction of the main information are performed by setting a focus offset amount between the set amount and the second focus offset amount. 2. A disk substrate having a spirally or concentrically formed guide groove or pit having address information thereon, and an information signal of main information formed on the disk substrate and recorded according to the direction of magnetization of a perpendicular magnetization film. A recording / reproducing method for a magneto-optical disc comprising a reproducible recording film, wherein a laser beam is condensed on the magneto-optical disc to perform recording and reproduction of information; A first focus offset amount detected by a differential signal at a light receiving unit divided into a plurality of portions according to the polarization direction by rotating the polarization plane of the reflected light of the condensed laser light according to the direction of the laser beam. The first focus offset amount and the second focus offset value, using a second focus offset amount detected by an addition signal in a plurality of divided light receiving units. A method for recording / reproducing a magneto-optical disk, wherein the reproduction of the address information and the recording / reproduction of the main information are performed by setting a focus offset amount between the offset amount and the focus offset amount. 3. A first focus offset amount,
3. The recording / reproducing method for a magneto-optical disk according to claim 1, wherein a focus offset amount at which a modulated signal amplitude of the main information is maximized is used. 4. The method according to claim 1, wherein the first focus offset amount is:
3. The method for recording / reproducing a magneto-optical disk according to claim 1, wherein a focus offset amount that minimizes a jitter of a binarized information signal of the reproduction signal is used. 5. The method according to claim 1, wherein the first focus offset amount is:
3. The recording / reproducing method for a magneto-optical disk according to claim 1, wherein a focus offset amount that minimizes an error rate of a main information signal demodulated after binarizing the reproduction signal is used. 6. A second focus offset amount,
2. The method according to claim 1, wherein a focus offset amount at which the amplitude of the modulated signal of the address information is maximized is used. 7. A second focus offset amount,
2. The recording and reproducing method for a magneto-optical disk according to claim 1, wherein a focus offset amount that minimizes a jitter of a binarized information signal of the reproduction signal is used. 8. A second focus offset amount,
2. The method according to claim 1, wherein a focus offset amount that minimizes an error rate of a signal of address information demodulated after binarizing the reproduction signal is used. 9. The method according to claim 9, wherein the second focus offset amount is:
2. The magneto-optical disk according to claim 1, wherein a focus offset amount set by offsetting a predetermined value in a focus direction from a focus position at which the error rate of the address information signal demodulated after binarizing the reproduction signal starts increasing is used. Recording and playback method. 10. The method according to claim 1, wherein the second focus offset amount is 1.
The recording / reproducing method for a magneto-optical disk according to claim 9, wherein the thickness is 0 µm or more. 11. The recording / reproducing method for a magneto-optical disk according to claim 6, wherein the second focus offset amount is set by using a difference or an addition signal in the rotation direction of the magneto-optical disk. 12. A first focus offset amount and a second focus offset amount.
3. The recording / reproducing method for a magneto-optical disk according to claim 1, wherein the reproduction of the address information and the recording / reproduction of the main information are performed by setting the focus offset amount to an intermediate value of the focus offset amount. 13. The method according to claim 1, wherein the setting of the focus offset amount is performed when the magneto-optical disk is inserted. 14. The method according to claim 1, wherein the setting of the focus offset amount is performed at the start of recording of the main information. 15. The magneto-optical disk recording / reproducing method according to claim 1, wherein the setting of the focus offset amount is performed for each predetermined radius or predetermined address in the magneto-optical disk. 16. The recording / reproducing of the magneto-optical disk according to claim 1, wherein the setting of the focus offset amount is performed for each predetermined radius or predetermined address in the magneto-optical disk, and the set focus offset amount is stored. Method. 17. The method according to claim 1, wherein the setting of the focus offset amount is performed at regular time intervals. 18. A method of detecting a second focus offset amount when a magneto-optical disk is inserted, and detecting the detected second focus offset amount.
3. The recording / reproducing method for a magneto-optical disk according to claim 1, wherein the focus offset amount is stored. 19. The recording / reproducing method for a magneto-optical disk according to claim 1, wherein the focus offset amount is detected by switching the laser power of the laser light applied to the magneto-optical disk a plurality of times. 20. The recording / reproduction of a magneto-optical disk according to claim 1, wherein a focus offset amount is detected by switching a laser power of a laser beam applied to the magneto-optical disk a plurality of times, and the detected focus offset amount is stored. Method. 21. The magneto-optical disk recording / reproducing method according to claim 1, wherein the first focus offset amount is detected using a maximum amplitude value or a minimum jitter value based on main information after waveform equalization. 22. A light source comprising: a disk substrate having a spirally or concentrically formed guide groove or pit having address information; and a recording film formed on the disk substrate and capable of recording and reproducing main information. A recording / reproducing apparatus for a magnetic disk, wherein when performing focus control when recording and reproducing information by condensing a laser beam on the magneto-optical disk, a plurality of magnetic disks are provided according to the polarization direction of main information of the magneto-optical disk. A first focus offset amount detected by a differential signal at a divided light receiving unit and a second focus detected by a differential signal at a plurality of light receiving units divided in a radial direction of the magneto-optical disk. And setting the focus offset amount between the first focus offset amount and the second focus offset amount by using the offset amount. A recording / reproducing apparatus for a magneto-optical disk, which reproduces address information and records / reproduces the main information. 23. A light source comprising: a disk substrate having a spirally or concentrically formed guide groove or pit having address information; and a recording film formed on the disk substrate and capable of recording and reproducing main information. A recording / reproducing apparatus for a magnetic disk, wherein when performing focus control when recording and reproducing information by condensing a laser beam on the magneto-optical disk, a plurality of magnetic disks are provided according to the polarization direction of main information of the magneto-optical disk. Using a first focus offset amount detected by a differential signal at the divided light receiving unit and a second focus offset amount detected by an addition signal at the plurality of divided light receiving units, A focus offset amount between the first focus offset amount and the second focus offset amount, and reproduction of the address information and reproduction of the main information. A recording and reproducing apparatus for a magneto-optical disk, which performs recording and reproduction. 24. The magneto-optical disk recording / reproducing apparatus according to claim 22, further comprising an area for storing at least one of the first focus offset amount and the second focus offset amount.