JPH0612718A - Magneto-optical information recording and reproducing device - Google Patents

Abstract

PURPOSE:To enable good high-density recording and reproducing by providing a means for detecting prescribed patterns in a recording signal in order to decrease the inter-code interference generated at the time of reproducing in magneto-optical recording and reproducing in a magnetic modulation recording system. CONSTITUTION:The shortest pattern is detected in a shortest pattern detecting circuit 9 from the recording signal inputted to a recording compensation circuit 13 via an endic 8 from a CPU 7 in the case of reproducing the recording pit patterns on a magneto-optical disk 1. The recording compensation to move forward the front edge of the shortest pattern in the recording signal is executed in a timing adjustment circuit 10 if the other pattern exists before the front edge of the shortest pattern. The rear edge of the shortest pattern in the recording signal is similarly moved backward if the other pattern exists behind the rear end of the shortest pattern. A floating magnetic head 11 is controlled via a magnetic head driver 12 by these recording signals after the edge movement processing. Then, the good recording and reproducing are executed and the capacity is increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magneto-optical information recording / reproducing apparatus, and more particularly to a magnetic field modulation recording type magneto-optical information recording / reproducing apparatus.

[0002]

2. Description of the Related Art Conventionally, the problems to be solved by the invention
Research and development of an optical memory that performs recording and reproduction by using laser light as a high-density and large-capacity memory has been actively conducted, and among them, a magneto-optical recording medium has attracted much attention as a rewritable memory.

In a magneto-optical recording medium, information is recorded as an array of magnetic domains (information track) having a magnetization direction different from that of a recording pit, that is, by heating a magnetic layer locally by irradiating a spot of laser light. Will be recorded. Further, the information thus recorded as the recording pit row is reproduced by using the magneto-optical effect by scanning with a laser beam focused in a spot shape and detecting the reflected light of this laser beam through an analyzer. be able to.

With the recent demand for large capacity, the recording pits must be made as small as possible in order to achieve high density of the magneto-optical recording medium. As a method for forming such a small recording pit, there is a magnetic field modulation recording method in which a recording pit is formed by modulating a magnetic field according to a recording signal while continuously irradiating a laser beam. According to this magnetic field modulation recording method, it is possible to form a recording pit smaller than the spot diameter of laser light.

FIG. 12 shows a schematic explanatory diagram of the magnetic field modulation recording method. When recording a recording signal like (a), (c)
As described above, the laser light intensity is used as the recording power, and the modulation magnetic field (b) corresponding to the recording signal is applied to the recording portion. as a result,
A recording pit pattern as shown in (d) is formed and recording is performed. When this recording pit pattern is reproduced, a reproduction waveform as shown in (e) is read out as a magneto-optical signal. By binarizing this reproduced waveform (e) by, for example, a slice level, a reproduced signal as shown in (f) is obtained, and this reproduced signal corresponds to the recorded signal (a). According to such a magnetic field modulation recording method, by appropriately selecting the magnetic layer structure of the recording medium, information can be overwritten regardless of the presence or absence of recording pits before writing.

In the magneto-optical recording / reproducing as described above, when the magnetization reversal interval of the recording pit pattern becomes smaller than the reproducing light beam spot diameter determined by the laser wavelength and the performance of the condenser lens, the space becomes spatial. , The inter-code interference occurs in the track direction of the recording pit, and the amplitude of the reproduced waveform decreases. There is a problem in that an edge shift occurs in the reproduced signal obtained by binarizing such a reproduced waveform and the error rate increases.

FIG. 13 is a schematic explanatory view of the edge shift generation of the reproduction signal. When the recording pits are smaller than the laser beam spot diameter for reproduction, the recording pits before and after are reproduced at the same time, and the reproduction waveform becomes like the broken line of (e), which is the original ideal shown by the solid line. The amplitude is smaller than that of a normal playback waveform. A reproduced signal obtained by binarizing this reproduced waveform at a certain slice level has front and rear edges τ _L and τ _T from the original edge position, respectively, as shown in (f).
The pulse length becomes shorter (edge shift) and the pulse length becomes shorter. This edge shift is a major drawback in pit edge recording due to the demand for high density recording.

It is known that the recording pit width has a recording pit length dependency. When the recording pit length is short, the recording pit width becomes narrow, and when the recording pit length is overwritten with a short pit length. There was a problem that the amount of unerased material increased. Furthermore, when overwriting occurs due to fluctuations in recording power or detracking during overwriting, the amplitude of the reproduced waveform decreases due to intersymbol interference, which makes it more susceptible to amplitude fluctuations due to unerasing and increasing edge shift. That is, there is a problem that the error rate is increased.

[0009]

According to the present invention, in order to solve the above problems, a light spot formed by irradiating a light beam onto a magneto-optical recording medium is scanned on the recording medium. While applying a magnetic field modulated according to a recording signal to a light spot forming portion of the recording medium, a magnetic domain array having a magnetization direction corresponding to the recording signal is applied to the recording medium on the optical spot scanning path. An information track is formed to record information, and the information track is scanned with an optical spot formed by irradiating the recording medium with a light beam to detect the light subjected to the magneto-optical effect by the magnetization of the magnetic domains. A magneto-optical information recording / reproducing apparatus for reproducing information by means of a magneto-optical information recording / reproducing apparatus, comprising: predetermined pattern detecting means for detecting a predetermined pattern in the recording signal. Device, is provided.

In one aspect of the present invention, the predetermined pattern detecting means outputs a signal including position information of front and rear edges of the predetermined pattern.

In another aspect of the present invention, the predetermined pattern is the shortest pattern.

In still another aspect of the present invention, when the shortest pattern detecting means detects that a pattern other than the shortest pattern exists before the front edge of the shortest pattern, the shortest pattern in the recording signal is detected. When the presence of a pattern other than the shortest pattern after the shortest pattern rear edge is detected by the shortest pattern detection means, the rear edge of the corresponding shortest pattern in the recording signal is moved forward. Is moved to the rear, and the recording operation is performed using the recording signal after the edge moving processing. Here, the movement amount of the front edge and the movement amount of the rear edge can be made variable.

In another aspect of the present invention, when recording the predetermined pattern, the intensity of the light beam is higher than when recording a pattern other than the predetermined pattern. here,
An isolated or continuous shortest pattern can be selected as the predetermined pattern, and the timing of increasing the intensity of the light beam at the time of recording the predetermined pattern,
This can be earlier than the timing of modulating the magnetic field according to the recording signal.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a schematic configuration of a first embodiment of the present invention. In FIG. 1, reference numeral 1 is a magneto-optical disk which is a magneto-optical recording medium, 2 is a spindle motor for rotating the magneto-optical disk 1 at a predetermined number of revolutions, and 3 is information recording on the magneto-optical disk 1 using laser light. This is an optical head for performing and reading the information recorded on the magneto-optical disk 1. Reference numeral 4 is a head amplifier for amplifying a signal from an information reading optical sensor built in the optical head 3.
Is a waveform equalization circuit for reducing intersymbol interference during reproduction, particularly when the shortest pattern of the reproduction signal from the head amplifier is continuous, 6 is an analog signal waveform output from the waveform equalization circuit 5, which is "1", A binarization circuit for converting into a digital signal of "0", 7 is a CPU, 8 is an endeck for encoding and decoding, and 9 is pattern detection for finding a predetermined pattern from a recording data signal. A circuit 10 is a timing adjustment circuit for advancing or delaying the timing of the recording signal based on the detection signal of the detection circuit 9. The recording compensation circuit 13 is composed of the detection circuit 9 and the timing adjustment circuit 10. Reference numeral 11 is a flying magnetic head that switches the polarity of the magnetic field applied to the magneto-optical disk 1 according to a recording signal, and reference numeral 12 is a magnet for supplying a current according to the recording signal to a coil wound around the core of the floating magnetic head. It is a head driver.

Next, as a pattern requiring recording compensation, there is a shortest pattern continuous with other patterns. For example, in the case of (1-7) NRZ code, when the shortest pattern 2T and other patterns are continuous, that is, 2T-.
This is the case of a combination of 3T, 2T-4T, ..., 2T-8T.

FIG. 2 shows an example of the pattern detection circuit 9 for detecting the shortest pattern 2T. 3 and 4 are timing charts for explaining the operation of this shortest pattern detection circuit.

First, the detection of the shortest pattern 2T on the negative side of the recording signal will be described with reference to FIGS. The recording data signal is input to the shift register to obtain signals A, B, C and D that are shifted by 1 bit. When A and B are input to the OR circuit, the output becomes E, and when C and D are input to the OR circuit, the output becomes F. AND with E and F
Input to the circuit to obtain G, and take the AND output of this and H which is the inverted signal of C. 2T on the negative side corresponding to signal C
Leading edge signal I is detected. When this I is further shifted by 2 bits by the shift register, the trailing edge signal J of 2T on the negative side is obtained.

Next, the detection of the shortest pattern 2T on the positive side of the recording signal will be described with reference to FIGS. The recording data signal is input to the shift register to obtain a signal shifted by 1 bit, and the inverted signal A ′ of these signals,
Obtain B ', C', D '. When A'and B'are input to the OR circuit, the output becomes E'and C'and D'are ORed.
When input to the circuit, its output will be F '. E'and F '
And are input to the AND circuit to obtain G ', and C and H'
When the AND output of and is taken, 2 on the positive side corresponding to signal C
The leading edge signal I ′ of T is detected. When this I'is further shifted by 2 bits in the shift register, the positive side 2T
The trailing edge signal J'is obtained.

Therefore, as shown in FIG. 2, the detection signal of the leading edge of the pattern 2T is obtained by ORing I and I ', and the pattern is obtained by ORing J and J'. A detection signal of the trailing edge of 2T is obtained.

Next, the recording timing adjusting circuit 10 is shown in FIG.
For example: The recording data signal is transferred to three delay lines D
Input to L1, DL2, DL3. Assuming that the time at the time of this input is t ₀ , the time of each output X, Y, Z is X
= T ₀ + τ ₁ , Y = t ₀ + τ ₂ , Z = t ₀ + τ ₃ (0 <
τ ₁ <τ ₂ <τ ₃ ). Here, when Y is the reference recording signal, it is possible to regard X as an advanced signal and Z as a delayed signal, and the front edge signal and the rear edge signal which are the shortest pattern detection signals obtained by the pattern detection circuit 9 are obtained. Is used as a control signal of the multiplexer to select each of the signals X, Y and Z, so that the recording timing can be adjusted (recording compensation). That is, when the presence of the front edge is indicated by the front edge signal, the signal X is selected and output for the signal portion having the front edge, and the presence of the rear edge is indicated by the rear edge signal. For the signal portion having the trailing edge, the signal Z is selected and output, and otherwise the signal Y is output. Thereby, the width of the shortest pattern can be widened.

Next, the relationship between the edge movement of the recording signal and the reproduction signal as described above will be described with reference to FIG. When the recording pits indicated by the solid line in (b) recorded according to the shortest pattern recording signal before the recording compensation indicated by the solid line in (a) are reproduced by irradiating the laser light spot shown in (b), intersymbol interference occurs. As a result, the reproduced waveform becomes as shown by the broken line in (c), and the reproduced signal obtained by binarizing this becomes shorter than the width of the recording signal as shown by the broken line in (d). Therefore, as described above, the front edge of the shortest pattern recording signal is moved to the front and the rear edge is moved to the rear to lengthen the pulse width of the shortest pattern recording signal to perform the recording compensation as shown by the broken line in (a). To do. As a result, the length of the recording pit formed on the recording medium becomes longer than that before recording compensation as shown by the broken line in (b). When the recorded pits after the compensation are reproduced by irradiating the laser light spot shown in (b), the reproduced waveform becomes as shown by the solid line in (c) due to intersymbol interference, and this is binarized. The reproduced signal thus obtained has the same width as that of the recording signal before compensation as shown by the solid line in (d).
Set ₁ , τ ₂ , τ ₃ ).

The recording compensation as described above has a great effect when it is applied when patterns other than the shortest recording pattern exist before and after the shortest recording pattern. However, even when a pattern other than the shortest recording pattern exists before or after the shortest recording pattern, the error rate is reduced by moving the shortest recording pattern edge on the side of the pattern other than the shortest recording pattern. be able to.

FIG. 7 is a diagram showing a schematic configuration of the second embodiment of the present invention. In the figure, the same parts as those in FIG. 1 are designated by the same reference numerals.

ZCAV is one of further techniques for high-density recording on a magneto-optical disk. In ZCAV, the magneto-optical disk is divided into several zones in the radial direction, and the recording frequency is changed for each zone to make the size of corresponding recording pits formed in all zones constant and within a reproducible range. Make it as small as possible to increase recording capacity. The conventional CAV is disadvantageous in increasing the capacity because the size of the corresponding recording pit changes depending on the radial position of the disk.

In this embodiment, a recording compensation circuit compatible with ZCAV is used. That is, FIG. 7 is different from FIG. 1 in that the adjustment time (τ ₁ , τ ₂ , τ ₃ ) of the recording timing adjustment circuit 10a can be arbitrarily changed. The variable timing adjustment circuit 10a will be described with reference to FIG. In ZCAV, since the recording frequency changes for each zone, the optimum compensation amount also changes for each zone. The variable timing adjustment circuit makes it possible to adjust this compensation amount for each zone. Specifically, it is a circuit that can adjust the amount of movement of the leading edge and trailing edge of the recording signal of the shortest pattern according to the recording frequency that differs depending on the recording zone. That is, as shown in FIG. 7, the recording data is transferred to three programmable delay lines PDL1 and PDL.
2, input to PDL3. These programmable delay lines can change the delay amount according to the zone information from the CPU 7. The time at the time of input is t
_If 0'is set, the time of each output X ', Y', Z'is
_{X '= t 0' + τ} 1 ', Y' = t 0 '+ τ 2', Z '=
t ₀ '+ τ ₃ ' (0 <τ ₁ '<τ ₂ '<τ ₃ '; τ
_{1 ', τ 2', τ} 3 ' becomes variable). Here, when Y'is the reference recording signal, X'can be regarded as the advanced signal and Z'can be regarded as the delayed signal, and the recording compensation can be performed in the same manner as in the first embodiment. Of course, the above τ
₁ ', τ ₂ ' and τ ₃ 'can be changed appropriately depending on the recording zone.

A recording area for testing is provided on the recording medium, and a recording / reproducing test is conducted in advance to obtain
It is also possible to set ₁ , τ ₂ , τ ₃ and τ ₁ ′, τ ₂ ′, τ ₃ ′ to be optimal under the conditions at that time.

FIG. 9 is a diagram showing a schematic configuration of the third embodiment of the present invention. In FIG. 9, reference numeral 21 denotes a magneto-optical disk in which a substrate 22 made of glass or plastic is coated with a magnetic layer 23 and a protective film 24 is further formed thereon. The magneto-optical disk 21 is supported by a spindle motor (not shown) by magnet chucking or the like, and has a structure rotatable about a rotation shaft. 25 is an actuator, 2
6 is a semiconductor laser, 27 is a condenser lens, 28 is a beam shaping lens, 29 is a beam splitter, 30 is a half-wave plate, 31 is a polarization beam splitter, 32 is a condenser lens,
33 is an optical sensor. The above 25 to 33 are members constituting an optical head for spot-irradiating the magneto-optical disk 21 with laser light and further obtaining information from the reflected light.

Laser light emitted from the semiconductor laser 26 is applied to the magneto-optical disk 21 via a beam shaping lens 28, a beam splitter 29, and a condenser lens 27.
At this time, the condensing lens 27 is controlled by the actuator 25 so as to move in the focusing direction and the tracking direction so that the laser light is focused on the magnetic layer 23 of the magneto-optical disk 21, and is also marked on the magneto-optical disk. It is configured to track along a rare guide groove. The laser beam reflected by the magneto-optical disk 21 has its optical path changed to the polarization beam splitter 31 by the beam splitter 29, and the magnetic layer 23 of the magneto-optical disk is magnetized via the half-wave plate 30 and the polarization beam splitter 31. The respective polarities of are collected by the lens 32 on the sensor 33 respectively. The output of each sensor is the differential amplifier 34.
Is differentially amplified by and outputs a magneto-optical signal.

The controller 37 controls the LD driver 38 for driving the semiconductor laser 26 by using the output of the temperature sensor 36, the rotational speed of the magneto-optical disk and the radial position of the recording portion as input information. Further, the controller 37 determines the recording channel frequency from the radial position and the rotational speed at which the recording operation is performed, and provides the predetermined pattern detection and phase adjustment circuit 41 with the phase switching information of the power of the recording laser light and the phase information of the modulation magnetic field. It is what is output. The predetermined pattern detection and phase adjustment circuit 41 is a circuit that detects a predetermined pattern of the recording signal and determines a period for increasing the recording laser power, and also the controller 3
7 is a circuit that sets the phase of the laser power switching timing and the phase of the modulation magnetic field to a predetermined value according to the phase information of the recording laser power switching timing and the modulation magnetic field output from the recording medium 7. Therefore, the predetermined pattern detection and phase adjustment circuit 41 outputs the recording laser power modulation signal to the LD driver 38 and the modulation magnetic field signal to the magnetic field modulation driver 40.

Reference numeral 39 denotes a floating magnetic head for applying a modulating magnetic field to the laser light irradiation portion of the magneto-optical disk at the time of recording operation, sandwiching the magneto-optical disk 21 and condensing lens 2.
It is arranged so as to face 7. This floating magnetic head 39
The magnetic field modulation driver 40 generates magnetic fields having different polarities in accordance with the timing of the recording signal output from the predetermined pattern detection and phase adjustment circuit 41. The flying magnetic head 39 moves in the radial direction of the magneto-optical disk 21 in conjunction with the optical head, and at the time of recording, information is recorded by sequentially applying a magnetic field to the laser light irradiation portion of the magnetic layer 23 of the magneto-optical disk 21. It is supposed to do.

FIG. 10 is a timing chart of the operation in this embodiment. (A) is a recording signal, (b) is a modulating magnetic field,
(C) is the recording laser light intensity, (d) is the recording pit pattern, (e) is the reproduction magneto-optical signal waveform, and (f) is the reproduction binary signal.

When recording a signal as shown in (a), a recording signal is first sent from the controller 37 to the predetermined pattern detecting and phase adjusting circuit 41. At this time, the controller 37 calculates a predetermined recording laser power from the radial position for performing the recording operation and the number of rotations, and further detects the temperature in the vicinity of the magneto-optical disk 21 by the temperature sensor 36 to change the recording sensitivity depending on the ambient temperature. In consideration of the above, two optimum predetermined recording power information are finally sent to the LD driver 38. Further, the controller 37 sends to the predetermined pattern detection and phase adjustment circuit 41 predetermined phase information to be shifted between the recording laser power switching timing and the modulation magnetic field under this condition. When recording a predetermined recording pattern (here, the shortest pattern of the minimum magnetization reversal interval), the predetermined pattern detecting and phase adjusting circuit 41 outputs a signal to the LD driver 38 so as to output a high laser power during that period. At this time, the predetermined pattern detecting and phase adjusting circuit 41 according to the phase information output from the controller 37, the phase of the recording signal output to the magnetic field modulation driver 40 and the phase of the recording laser power switching signal output to the LD driver 38. Are set so that the switching timing of the recording laser power is advanced with respect to the magnetic field modulation signal, as shown in (b) and (c) of FIG. This is because when the recording laser power is increased, it takes some time for the temperature of the magnetic film on which the recording is performed to rise, so that the switching timing of the recording laser power and the modulation magnetic field are changed so that the width of the magnetic domain in the predetermined pattern widens. The phase is corrected. When recording is performed with the combination of the modulation magnetic field and the recording laser power thus determined, the recording pits schematically shown in (d) are formed. Here, the white part is a state in which a magnetic domain having a downward magnetization direction is formed, and the shaded portion is a state in which a magnetic domain having a upward magnetization direction is formed. As shown here,
In this embodiment, the width of the recording pit becomes large only when a predetermined recording pattern (shortest pattern of the minimum magnetization reversal interval) is recorded.

Therefore, as shown in FIG. 11, in the conventional method, when the pit pattern shown by the broken line in (d) is reproduced, the magneto-optical signal amplitude decreases as shown by the broken line in (e) (f).
Although an edge shift occurs in the reproduction binarized signal as shown by the broken line in FIG. 3, in the present embodiment, since the pit pattern shown by the solid line in (d) is reproduced, the conventional method is shown as shown by the solid line in (e). As compared with the result (f) in which the amplitude of the magneto-optical signal is increased, the edge shift of the reproduced binarized signal can be sufficiently reduced, and the error rate can be prevented from increasing.

Further, when the amplitude of the magneto-optical signal increases, even if there is an unerased portion due to fluctuations in recording power or detrack, it is less susceptible to the fluctuation in the amplitude of the magneto-optical signal due to the unerased portion, and the error rate is reduced. The increase can be reduced. Further, when a predetermined pattern is further recorded, since the width of the recording pit is large in the width direction, it is possible to prevent the generation of the unerased portion itself.

In this embodiment, the predetermined pattern is the shortest pattern with the minimum magnetization reversal interval, and the recording laser power is 2
However, as the predetermined pattern, it is possible to target all patterns in which intersymbol interference occurs, and by controlling the recording laser power with different values according to the edge shift and with no value, a greater effect can be obtained. Obtainable.

[0037]

As described above, according to the present invention, when there is a pattern other than the shortest pattern in front of, in the back of, or in front of the shortest pattern in which intersymbol interference is significant, before the recorded signal of the shortest pattern is present. By performing recording compensation by moving the edge forward and the rear edge backward, the edge position and pulse width of the binarized pulse signal at the time of reproduction can be made appropriate, and stable recording / reproduction can be performed by this. It is possible to increase the capacity. Furthermore, ZCAV
Corresponding to the above, by adjusting the movement amount of the leading edge and the trailing edge of the recording signal of the shortest pattern according to the recording frequency of each zone, it is possible to stably increase the capacity further.

Further, according to the present invention, when recording a pit pattern having an isolated or continuous minimum magnetization reversal interval, the recording laser power is recorded when another pit pattern is recorded by the means for modulating the recording laser power. The predetermined pit pattern is recorded large in the width direction by increasing the laser power higher than the laser power and the timing for increasing the recording laser power earlier than the phase of the modulation magnetic field, and the reproduction magneto-optical property due to the intersymbol interference of the predetermined pit pattern is recorded. This has the effect of suppressing a decrease in signal amplitude and reducing edge shift. Furthermore, by increasing the amplitude of the reproduced magneto-optical signal, it is possible to reduce the edge shift due to the influence of the amplitude fluctuation that occurs when the unerased residue occurs, and by recording the magnetic domain wide in the width direction in the case of a predetermined pit pattern, Even if the pit length of the overwrite is short, there is an effect that the erased portion itself can be reduced.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of a first embodiment of the present invention.

FIG. 2 shows an example of a shortest pattern detection circuit.

FIG. 3 is a timing chart for explaining the operation of the shortest pattern detection circuit.

FIG. 4 is a timing chart for explaining the operation of the shortest pattern detection circuit.

FIG. 5 is a diagram showing an example of a recording timing adjustment circuit.

FIG. 6 is a diagram showing a relationship between an edge movement of a recording signal and a reproduction signal.

FIG. 7 is a diagram showing a schematic configuration of a second embodiment of the present invention.

FIG. 8 is a diagram showing an example of a variable timing adjustment circuit.

FIG. 9 is a diagram showing a schematic configuration of a third embodiment of the present invention.

FIG. 10 is a timing diagram of the operation of the embodiment of FIG.

FIG. 11 is a timing diagram of the operation of the embodiment of FIG.

FIG. 12 is a schematic explanatory diagram of a magnetic field modulation recording method.

FIG. 13 is a schematic explanatory diagram of edge shift generation of a reproduction signal.

[Explanation of symbols]

 1 Magneto-optical disk 2 Spindle motor 3 Optical head 4 Head amplifier 5 Waveform equalization circuit 6 Binarization circuit 7 CPU 8 Endec 9 Pattern detection circuit 10, 10a Timing adjustment circuit 11 Levitation magnetic head 12 Magnetic head driver 13 Recording compensation circuit 21 Magneto-optical disk 25 Actuator 26 Semiconductor laser 27 Condensing lens 28 Beam shaping lens 29 Beam splitter 30 1/2 wavelength plate 31 Polarizing beam splitter 32 Condensing lens 33 Optical sensor 34 Differential amplifier 36 Temperature sensor 37 Controller 38 LD driver 39 Levitation Magnetic head 40 Magnetic field modulation driver 41 Predetermined pattern detection and phase adjustment circuit

Claims (8)

[Claims] 1. A magnetic field modulated according to a recording signal to a light spot forming portion of the recording medium while scanning the recording medium with a light spot formed by irradiating a light beam onto the magneto-optical recording medium. Is applied to the recording medium to form an information track in the optical spot scanning path as a row of magnetic domains having a magnetization direction according to a recording signal to record information, and the recording medium is spot-irradiated with a light beam. In a magneto-optical information recording / reproducing apparatus for sequentially detecting light that has undergone a magneto-optical effect due to magnetization of the magnetic domains while scanning the information track with a light spot formed by A magneto-optical information recording / reproducing apparatus having a predetermined pattern detecting means for detecting the pattern. 2. The magneto-optical information recording / reproducing apparatus according to claim 1, wherein the predetermined pattern detecting means outputs a signal including position information of both front and rear edges of the predetermined pattern. 3. The magneto-optical information recording / reproducing apparatus according to claim 1, wherein the predetermined pattern is a shortest pattern. 4. When the shortest pattern detecting means detects that a pattern other than the shortest pattern exists before the front edge of the shortest pattern, the front edge of the corresponding shortest pattern in the recording signal is moved forward. When the presence of a pattern other than the shortest pattern after the rear edge of the shortest pattern is detected by the shortest pattern detecting means, the rear edge of the shortest pattern in the recording signal is moved backward, The magneto-optical information recording / reproducing apparatus according to claim 3, wherein a recording operation is performed using the recording signal after the edge movement processing. 5. The magneto-optical information recording / reproducing apparatus according to claim 4, wherein the moving amount of the front edge and the moving amount of the rear edge are variable. 6. The magneto-optical information recording / reproducing apparatus according to claim 1, wherein the intensity of the light beam is higher when recording the predetermined pattern than when recording a pattern other than the predetermined pattern. 7. The magneto-optical information recording / reproducing apparatus according to claim 6, wherein the predetermined pattern is an isolated or continuous shortest pattern. 8. The magneto-optical information recording / reproducing according to claim 6, wherein the timing of increasing the intensity of the light beam when recording the predetermined pattern is earlier than the timing of modulating the magnetic field according to the recording signal. apparatus.