JPH01277351A - Magneto-optical recording and reproducing device - Google Patents

Abstract

PURPOSE:To suppress the generation of a unerased area by setting up the energy of pulse-like laser beams irradiating at timings close to the positive maximum value of an AC magnetic field differently from that of pulse-like laser beams irradiating at timings close to the negative maximum value. CONSTITUTION:The energy of pulse-like laser beams irradiating to a magneto- optical recording medium 4 at the prescribed timings t1, t3, t5, t7,... close to the positive maximum value of the AC magnetic field HW is set up differently from that of pulse-like laser beams irradiating to the medium 4 at the prescribed timings t0, t2, t4, t6,... close to the negative maximum value of the AC magnetic field HW. Consequently, the area of an unerased area AR10 can be reduced at the time of forming new recording patterns PTN2, PTN30 corresponding to recording data to the surface of recording patterns PTN0, PTN10 formed on the medium 4 and overwriting them.

Description

[Detailed description of the invention] The present invention will be explained in the following order.

A: Industrial field of application B: Outline of the invention C: Prior art (Figs. 4 and 5) D: Problems to be solved by the invention (Figs. 4 and 5) E: Means for solving the problems (Fig. 1 to Fig. 4) F action (Fig. 1 to Fig. 4) G embodiment (G1) First embodiment (Fig. 1 and Fig. 4) (G2) Second embodiment (Fig. 4) (Figures 2 and 4) (G3) Third embodiment (Figures 3 and 4) (G4) Other embodiments H Effects of the invention A Industrial field of application The present invention relates to magneto-optical recording and reproducing devices. For example, the present invention is suitable for application to a magneto-optical disk device that is capable of overwriting recorded data on a magneto-optical disk.

B Summary of the Invention The present invention applies an alternating magnetic field with a single frequency to a magneto-optical recording medium, and generates light at a predetermined timing near the maximum positive or negative value of the alternating magnetic field depending on recorded data. In a magneto-optical recording and reproducing apparatus that records recorded data on a magneto-optical recording medium by irradiating a magnetic recording medium with a pulsed laser beam, the first invention provides a magneto-optical recording and reproducing apparatus that records data on a magneto-optical recording medium by irradiating the magnetic recording medium with a pulsed laser beam. The energy of the pulsed laser beam to be irradiated and the energy of the pulsed laser beam to be irradiated at a timing near the negative maximum value of the alternating current magnetic field are made different, and in the second invention, depending on the recorded data,
A pulsed laser beam is applied to the magneto-optical recording medium at a timing when the alternating magnetic field is delayed by a predetermined period from the point when the alternating magnetic field reaches its maximum positive value, and a timing when the alternating current magnetic field is advanced by a predetermined period from when the alternating magnetic field reaches its negative maximum value. By irradiating the
When a new recording pattern corresponding to recording data is formed and overwritten on a recording pattern formed on a magneto-optical recording medium, the area of the unerased area can be reduced.

Furthermore, in the third invention, the energy of the pulsed laser light is emitted at a timing delayed by a predetermined period from the point in time when the alternating current magnetic field reaches its maximum positive value, and By changing the energy of the pulsed laser light that is emitted at a timing that is a predetermined period ahead of the value point, new information corresponding to the recorded data is created on the recording pattern formed on the magneto-optical recording medium. When forming a recording pattern and overwriting it, it is possible to substantially prevent unerased areas from occurring.

C. Prior Art Conventionally, in this type of magneto-optical recording and reproducing apparatus, an alternating current magnetic field of a single frequency is applied to a magneto-optical disk as a magneto-optical recording medium, and a magnetic field corresponding to one period of this alternating magnetic field is applied. When the recorded data to be recorded has the value "1", the pulsed laser beam is irradiated to the magneto-optical disk at a predetermined timing when the alternating current magnetic field is near the maximum positive value, and when the recorded data has the value "0". In this case, by irradiating a pulsed laser beam at a predetermined timing when this alternating magnetic field is near its maximum negative value, a new record is created on the recording pattern formed on the magneto-optical disk according to new recorded data. It has been proposed that patterns can be formed and overwritten (Japanese Unexamined Patent Application Publication No. 61-276103, Japanese Patent Application No. 1983).
1-180416).

That is, as shown in FIG. 4, in this magneto-optical disk device 1, a magneto-optical disk 4 is formed by coating a perpendicular magnetization [3 on a transparent protective substrate 2 made of polycarbonate, glass, etc., for example, by a spindle motor 5. It is configured to rotate around an axis O.

An electromagnet 6 is arranged above the magneto-optical disk 4, and a capacitor 7 is inserted in series with the coil of the electromagnet 6 to form a resonant circuit 8, and the coil of the electromagnet 6 is used as an oscillation coil. It is connected to the oscillation circuit 9. In this case, the resonant frequency f0 of the resonant circuit 8 is the C of the capacitor 7.
The highest frequency f of the recorded signal is given by f. The frequency 2f is twice that of
It is selected so that w.

Further, the oscillation circuit 9 is inputted with a clock signal 5cK (Fig. 5 (A)) obtained from the clock generation circuit 10, so that the oscillation circuit 9 is synchronized with the clock signal S0 at a frequency of 2f%, l. The alternating current magnetic field H%I (FIG. 5(B)) reversed in the directions of arrows H1 and H5 can be supplied to the perpendicularly magnetized film 3 of the magneto-optical disk 4.

(Then, this alternating magnetic field H, is the time tl St=% t,, t?, tv, 111 when the clock signal S0 rises.
It has a maximum positive value at the timing of . . . and the falling point of the clock signal Set L@, L! ,j4,it
, tl, jto, etc., and its strength is near the positive and negative maximum values and exceeds a value that can orient the magnetization direction of the perpendicularly magnetized film 3 in the direction of the magnetic field. It is set.

Here, the clock signal S0 obtained from the clock generation circuit 10 is input to the laser modulation circuit 11 into which the recording data set is input in addition to the oscillation circuit 9, so that the laser modulation circuit 11 is synchronized with the clock signal S0. do,
'When the recorded data S1 corresponding to one predetermined period of the AC magnetic field H8 applied to the magneto-optical disk 4 is the value rlJ, it rises at the timing when the AC magnetic field Hw reaches its maximum positive value, and conversely, the recorded data S When □ has the value "0", the recording signal S has a pulse waveform that rises at the timing when the AC magnetic field H1 reaches its negative maximum value. occurs.

That is, for example, if the recording data S0 is the value rl11101
If J is input sequentially, time 1. ,*s,L5,
A recording signal SwI (FIG. 5(C)) rising at timings t, , too and t is generated, and is sent to the semiconductor laser 1 of the optical pickup 13 via the laser drive circuit 12.
Supply to 4.

Thereby, the recording pulsed laser beam LPw emitted from the semiconductor laser 14 is transmitted from above by the electromagnet 6 to the magneto-optical disk 4 via the collimator lens 15, the polarizing beam splitter 16, and the objective lens 17 in the optical pickup 13. A light spot is formed from below at a position where the alternating current magnetic field H1 is applied.

Therefore, as described above, the value rl 1 is used as the recording data S1.
When 1101J is input sequentially, the perpendicular magnetization film 3 of the magneto-optical disk 4 is at the time! I', si! ,js,l? and tll, an elliptical recording pattern PT magnetized downward, for example, on the track center TRK.
NO (shown with diagonal lines in FIG. 5(D)), and an elliptical recording pattern PTN+ (shown with diagonal lines in FIG. 5(D)) which is magnetized upward at time t1°.
(shown in white) is formed so that a record data set can be recorded on the magneto-optical disk 4.

At this time, the laser beam reflected by the magneto-optical disk 4 is bent by the polarizing beam splitter 16 via the objective lens 17 and sent to the optical detector 19 by the condensing lens 18.
The received light output S obtained by concentrating the light on the ut is supplied to the clock generation circuit 10.

The clock generation circuit 10 has a light receiving output S. For example, the sample format included in the UL is reproduced and the magneto-optical disk 4 is
The rotational position information, etc. of the magneto-optical disk 4 is detected, and a clock signal SCI is generated in accordance with this information, thereby making it possible to prevent adverse effects on recording and reproducing operations due to uneven rotation of the magneto-optical disk 4. ing.

In this magneto-optical disk device 1, the value r1001 as the record data S0 is placed at the same position on the magneto-optical disk 4 on which the recording patterns P T N o and PTN of the value rllll101J are formed as the record data set as described above.
11J, the laser modulation circuit 11 operates in the same manner as described above to record time t+, LAN "h, tt,
The recording signal Swz rises at the timing of tw and t.
(FIG. 5(E)) and sends it to the laser drive circuit 12.
The light is supplied to the semiconductor laser 14 of the optical pickup 13 via.

As a result, the value [1111
In the recording pattern PTN of 01J and above PTN, the perpendicular magnetization film 3 of the magneto-optical disk 4 is at time 1.01J. ．． 1. ．． 1.
and a new elliptical recording pattern p'rNz that is magnetized downward at timing t9 (Fig. 5 (F)
(shown with diagonal lines) are formed and magnetized upward at time points t4 and t, creating a new elliptical recording pattern PTNs (shown in outline in FIG. 5(F)). are formed, and the recording patterns PTN@ and PTN are thus formed on the magneto-optical disk 4.

Recorded data Sll on top? New recording pattern P according to
T N and PTN2 can be overwritten.

Problems to be solved by the invention D By the way, the above-mentioned new recording patterns p'rNz and P
On the magneto-optical disk 4 overwritten with T N s,
As shown in FIG. 5(F), there is a problem in that there is an unerased area in which the previous recorded patterns PTN@ and P T N r remain.

In this magneto-optical disk device 1, the recording patterns p'rNz and P T formed on the magneto-optical disk 4 are
Sequentially sampling the recorded information consisting of N s (P T No and PTN,) with a reproduction pulsed laser beam L□ (Fig. 5 (G)) that rises at the same timing as when recording the value "1", for example. It is designed to obtain a reproduced signal by using this method, and is therefore particularly special.

At a predetermined position on the magneto-optical disk 4 where the recording pattern PTN6 having the value "1" is formed, a large unerased area A R+ is generated at the position where the recording pattern PTN3 having the value "0" is first formed. As a result, for example, it was not possible to avoid the possibility that the reproduction signal obtained by the reproduction pulsed laser beam LPII rising at the timing t3 would be contaminated with noise and the like and a reproduction error would occur.

The present invention has been made in consideration of the above points, and when a new recording pattern corresponding to new recording data is formed and overwritten on a recording pattern formed on a magneto-optical disk, as much as possible of the erased data is left on the recording pattern formed on the magneto-optical disk. This paper attempts to propose a magneto-optical disk device that prevents the generation of areas.

Means for Solving Problem E In order to solve this problem, in the first invention, an alternating current magnetic field H having a single frequency is applied to the magneto-optical recording medium 4.
1, H□, and pulsed laser beams LP1. ．． In the magneto-optical recording and reproducing apparatus 1 which records recording data S□ on the magneto-optical recording medium 4 by irradiating the magnetic field, the alternating current magnetic fields Hw, HwI are set at predetermined timings t1, ts, tS, tl, near the positive maximum value. The energy of the pulsed laser beam LPw irradiated onto the magneto-optical recording medium 4 and the predetermined timing t@, tl, j4, th, . . . . The energy of the pulsed laser beam L1 irradiated onto the magneto-optical recording medium 4 was made different.

Moreover, in the second invention, recorded data SD? According to the value of
xs, t□, tz't,... and AC magnetic field H
@, a predetermined period Δ with respect to the time when Hwl is the negative maximum value
Timing t2・, t 11St, advanced by τ! 4,
At t8..., the magneto-optical recording medium 4 was irradiated with the pulsed laser beam L□.

Furthermore, in the third invention, according to the value of the recording data S
The energy of the pulsed laser beam L7 irradiated onto the magneto-optical recording medium 4 and the alternating current magnetic fields Hw and Hw+ are at their negative maximum values only for a predetermined period. In the first invention, the F effect is such that the energy of the pulsed laser beam LPW irradiated onto the magneto-optical recording medium 4 differs at advanced timing t2°, ttffisig 1t..., the AC magnetic field H61 , a predetermined timing tISL! near the positive maximum value of Hw+! ,ts,t9
The energy of the pulsed laser beam irradiated onto the magneto-optical recording medium 4 and the alternating current magnetic field H,,8%1
1. A predetermined timing t@, jt near the negative maximum value
,'L4,j! By making the energy of the pulsed laser beam tpw irradiated onto the magneto-optical recording medium 4 different in ,..., the recording patterns formed on the magneto-optical recording medium 4 are recorded on PTN@, PTNIo. New recording pattern PTN according to data set! , P
When forming TN3° and overwriting, unerased area A
The area of R, , can be made small.

Further, in the second invention, timings tt, t, which are delayed by a predetermined period Δτ from the point in time when the alternating current magnetic fields H8, Hl, and lI are at their maximum positive values, according to the value of the recording data S air.
o, t□, to, ... and AC magnetic field Hw, H
A timing t8 is reached by a predetermined period Δτ with respect to the point in time when wI reaches its negative maximum value. S tt 1, I...
- Recording patterns PTNao, PTN@ formed on the magneto-optical recording medium 4 by irradiating the magneto-optical recording medium 4 with the pulsed laser beam L□. Above is a new recording pattern P T N according to the recording data SOT.
When forming and overwriting ar, PTNs+, the area of the unerased region AR2° can be made smaller.

Furthermore, in the third invention, recorded data S! Depending on the value of lT, the timing t is delayed by a predetermined period Δτ from the point in time when the alternating current magnetic fields Hw and Hw+ reach their maximum positive values! 1%
Ezss t□, txt, . . . with respect to the energy of the pulsed laser beam LPw irradiated to the magneto-optical recording medium 4 and the AC magnetic field H1, , H□ at the negative maximum value. Timing two, tz advanced by period Δτ
z, ts4, t! By making the energy of the pulsed laser beam L7 irradiated onto the magneto-optical recording medium 4 different, the recording pattern P TNioSP TN''l formed on the magneto-optical recording medium 4 was created. New recording pattern PTN, PTN□ according to recording data S□
When forming and overwriting, it is possible to substantially prevent the unerased area AR1° from occurring.

G example An embodiment of the present invention will be described in detail below with reference to the drawings.

(G1) First Embodiment In the first invention, the peak value of the energy of the recording pulsed laser beam L□ irradiated onto the magneto-optical disk 4 at the timing of the maximum positive value of the alternating current magnetic field H- is compared. hand,
The peak value of the energy of the recording pulse-shaped laser beam irradiated at the timing of the negative maximum value of the AC magnetic field H1 was set to a large value.

That is, in FIG. 1, in which parts corresponding to those in FIG. AC magnetic field H1 applied to the disk 4 (Fig. 1(B)
) Recorded data SD corresponding to one period of period? is the value rl
In the case of J, the first pulse waveform that rises at the timing when the AC magnetic field H, reaches its maximum positive value is generated, and conversely, when the recorded data S□ is the value "0", the AC magnetic field H@ A recording signal 51113, SWa, which rises at the timing of the negative maximum value and has a peak value larger than the first pulse waveform by ΔX, is generated, and is sent to the optical pickup 13 via the laser drive circuit 12. It is designed to be supplied to the semiconductor laser 14.

Therefore, the value rllll is recorded as the recording data SOW.

1" are input sequentially, the recording signal S. (FIG. 1(C)) is time t3, t3, t3, t-I.

It rises at the timing of til+ and tll, and at time t. becomes a pulse waveform in which the peak value of the waveform is larger by a predetermined amount ΔX, thereby causing the vertical magnetization film 3 of the magneto-optical disk 4 to appear at the time Lls it, js, j? It is magnetized downward at timings t and t, and an elliptical recording pattern PTNo (shown with diagonal lines in FIG. 1(D)) similar to the conventional one is formed. . At the timing of , it is magnetized upward and the conventional recording pattern PTNo.
, an elliptical recording pattern P that is a predetermined amount larger than PTNI.
TN+o (shown in outline in FIG. 1(D)) is formed,
This allows the recording data SDT to be recorded on the magneto-optical disk 4.

Furthermore, as mentioned above, the recorded data SD? as the value [111
Recording patterns PTN and PTNl of 101J. Recorded data S□ is placed at the same position on the magneto-optical disk 4 where
When sequentially recording the value r100111J as
A recording signal Swa (FIG. 1(E)) is generated which rises at timings a, tb, t7, tq, and tll, and whose peak values at time points t4 and t6 are larger by a predetermined amount ΔX, and is transmitted through the laser drive circuit 12. and supplies it to the semiconductor laser 14 of the optical pickup 13.

As a result, the above recorded data SI)? as value '11
1101J recording pattern P T No and PTN,
. Above, the perpendicular magnetization film 3 of the magneto-optical disk 4 is shown at the time jl.
A new elliptical recording pattern PTN that is magnetized downward at the timings of sL%, L'l, and t! (
(shown with diagonal lines in FIG. 1(F)) is formed, and at the timings t4 and t, it is magnetized upward and a new recording pattern with an oval shape larger than the conventional recording patterns PTNo and PTNI is formed. PTNs. (Figure 1 (F
) are formed, and thus the recording patterns PTN@ and PTN, of the magneto-optical disk 4 are formed. Above is a new recording pattern PTN according to the recording data set! and P
TNl. It is possible to overwrite.

The new recording pattern PTN thus formed!
and PTNs. In this method, a recording pattern P of value "0" is first formed at a predetermined position on the magneto-optical disk 4 on which a recording pattern P T N o of value "1" is formed compared to the conventional method.
T.N. The unerased area AR, which occurs when
. This reduces noise when obtaining a reproduction signal by sequentially sampling with the reproduction pulsed laser beam L□ (Fig. 1 (G)) that rises at the same timing as when recording the value "1". This is designed to prevent the risk of playback errors occurring due to contamination.

According to the above configuration, the alternating current magnetic field H8 of a single frequency is applied to the magneto-optical disk 4, and the recording data S□
A magneto-optical disk device that records recording data SDy on the magneto-optical disk 4 by irradiating the magneto-optical disk 4 with a pulsed laser beam L7 at the timing of the maximum positive or negative value of the AC magnetic field H1 according to 1, the alternating magnetic field H,l
is the maximum positive value timing t+ s ts, tsS t
With respect to the pulsed laser beam irradiated onto the magneto-optical disk 4 at t, tg, .
By increasing the pulsed laser beam pw irradiated onto the magneto-optical disk 4, the recording patterns PTNo and PTN of the magneto-optical disk 4 are obtained.

A new recording pattern p'r corresponding to the recording data S□ is shown above.
It is possible to realize a magneto-optical disk device 1 in which an unerased area AR, . is avoided as much as possible when forming Ng and PTN3° and overwriting.

In this way, it is possible to easily realize a magneto-optical disk device 1 that can prevent reproduction errors from occurring due to unerased areas during reproduction.

(G2) Second Embodiment In the second invention, the timing 11st8, tS, when the AC magnetic field H□ has the maximum positive value, according to the recorded data S□
Timing delayed by a predetermined period with respect to ... and timing L@, jl when the AC magnetic field H□ has the negative maximum value
,! The recording pulsed laser beam Lr, 4 is irradiated onto the magneto-optical disk 4 at a timing that is advanced by a predetermined period from 4, . . . .

That is, in FIG. 2, in which parts corresponding to those in FIG. AC magnetic field H% applied to the disk 4, 11 (Fig. 2 (B
)) If the recorded data S corresponding to one period of
Timing t2to, l t%s delayed by a predetermined time Δτ from tI, tco, tS, Ll, Ll, ......
j It rises at t7, to9, etc., and conversely, when the recording data set is the value "0", the AC magnetic field
is the maximum negative value at the timing t0, tt1t4, t4, t
Timing t, which is advanced by a predetermined time Δτ from . ,t! ts L 24, t, itt,...
Recording signal 5w5s consisting of a pulse waveform that rises at ...
Sub is generated and supplied to the semiconductor laser 14 of the optical pickup 13 via the laser drive circuit 12.

In the case of this embodiment, the AC magnetic field H□ applied to the magneto-optical disk 4 is set at the timing tl of the maximum positive and negative values.
% t, , Lss “”” and i@, j2, t4,・
Timing 1 delayed by a predetermined period with respect to...
1+, to, j! ! ISL l? , ttq, ...
...and advanced timing j tIs, j 1N, tt
a,t! &, tts, ...... generate a magnetic field larger than the conventional alternating current magnetic field H@ so that its intensity is greater than a value that can orient the magnetization direction of the perpendicularly magnetized film 3 in the direction of the magnetic field. It is made to be.

Therefore, when the value "rllll101" is sequentially input as the recording data S1, the recording signal 5w5 (FIG. 2(C)
) is the time t2to, t□, t□, which is delayed by a predetermined time Δτ with respect to the time LHs Ls, Ls,'' and tll.
The timing of tr+ and the time t,. A time point t, which has advanced by a predetermined time Δτ. As a result, the perpendicular magnetization film 3 of the magneto-optical disk 4 is magnetized downward at the timings t□, tI3, t2, t□, and t□, forming an ellipse similar to the conventional one. Shape recording pattern PTN. (shown with diagonal lines in FIG. 2(D)) is formed, whereas at time t,. At the timing of , the recording pattern P T N s is magnetized upward and has an oval shape similar to the conventional one. (shown in white in FIG. 2(D)) is formed so that recording data SST can be recorded on the magneto-optical disk 4.

Furthermore, as mentioned above, the value "1111" is set as the recording data S□.
01J recording pattern P T N a. and PTN,.

When sequentially recording the value rlo0111J as recording data SOT at the same position on the magneto-optical disk 4 where the
21%t! 4.t! th, txt, t□ and ti
Recording signal S rising at timing t.

(FIG. 2(E)) and sends it to the laser drive circuit 12.
The light is supplied to the semiconductor laser 14 of the optical pickup 13 via.

As a result, the value "1111" is set as the above-mentioned recorded data S
Recording pattern PTN of 01J. and PTN,. Above, the perpendicular magnetization film 3 of the magneto-optical disk 4 is exposed at time t! 1%!
A new elliptical recording pattern PTN that is magnetized downward at the timings of g"l, tffi9, and tI1.
.
) is formed, thus forming the recording pattern PTN of the magneto-optical disk 4. and p'rNs. Above is a new recording pattern P T N according to the recording data SOT.
a I and P T N s I can be overwritten.

The new recording pattern P T formed in this way
In N a s and P T N s r, the recording pattern P T N a has a value of “1” compared to the conventional one. At a predetermined position on the magneto-optical disk 4 on which the
It is possible to significantly reduce the area of the unerased area AR1° that occurs when the recording pattern P T N s I of “0” is formed. !・*R1% jl? s j goose 1 and te
Reproduction pulsed laser beam LP that rises at the timing of l
□ (FIG. 2 (G)) When sequentially sampling to obtain a reproduction signal, it is possible to prevent the possibility that noise will be mixed in and reproduction errors will occur.

According to the above structure, an alternating current magnetic field H□ of a single frequency is applied to the magneto-optical disk 4, and the recording data S1
The pulsed laser beam L□ is irradiated onto the magneto-optical disk 4 at a timing when the alternating current magnetic field H1 is near its positive or negative maximum value, and the recorded data SD is transferred to the magneto-optical disk 4.
In the magneto-optical disk device 1 for recording data, the time point when the alternating current magnetic field 1w+ reaches its maximum positive value according to the recording data set 1. , "2, *%Sjy, Lq, . . ., the time t□, tts, t□ is delayed by a predetermined period Δτ
, txt, t19, ...... timing and the time point t,% t,, tg, 6, t when the AC magnetic field has the maximum negative value
A time point t when a predetermined period Δτ has passed with respect to l, . . . Ito, tea, 1t tea,...
By irradiating the magneto-optical disk 4 with pulsed laser light and rw at the timing of , the recording patterns PTN4° and p'rNs of the magneto-optical disk 4 are recorded. Above is a new recording pattern according to recording data S1 P T
It is possible to realize a magneto-optical disk device 1 in which an unerased area A Rt @ is avoided as much as possible when forming and overwriting N a + and PTN, 1.

In this way, it is possible to easily realize a magneto-optical disk device 1 that can prevent reproduction errors from occurring due to unerased areas during reproduction.

(G3) Third embodiment The third invention is a combination of the first and second inventions, in which, according to the recorded data S Compared to the energy of the recording pulsed laser beam LPw that is irradiated onto the magneto-optical disk 4 at a timing delayed by a period of The energy of the recording pulsed laser beam L□ irradiated onto the magnetic disk 4 was set to a large value.

That is, in FIG. 3, in which parts corresponding to those in FIGS. 1 and 2 are given the same reference numerals, the laser modulation circuit 11 (the fourth
Figure) shows recorded data corresponding to one period of the alternating current magnetic field H□ (Figure 3 (B)) applied to the magneto-optical disk 4 in synchronization with the clock signal Sc* (Figure 3 (A)). When SIT has the value "1", the timing 1. when the AC magnetic field H□ has the maximum positive value. ,j$s Ls,tq,Lq,...
The timing is 1t delayed by a predetermined time Δτ from to,
t□, t□, t! 9. Generates the first pulse waveform that rises at... and conversely records data SD? is the value "0"
In the case of , the timing of the maximum negative value of the AC magnetic field HVN to, tg , tg , L 4 , ! @ ,...
...means a timing that is a predetermined time Δτ earlier than...
tss, t! 4. Rise at to, tss, . . . and generate recording signals Sw, , So having a pulse waveform whose peak value is larger by ΔX than the first pulse waveform,
This is passed through a laser drive circuit 12 to an optical pickup 13.
The laser beam is supplied to the semiconductor laser 14 of.

Therefore, the recorded data SO? When the values ``rllllO1'' are input sequentially, the recording signal Sw, (Fig. 3 (C
)) is the time Lls Lq, LSSL? and time t8 delayed by a predetermined time Δτ with respect to t, tg3, t□, tg
The recording pattern PTN is magnetized downward at the timing 'y, t□ and has an oval shape similar to the conventional one. (Figure 3 (D
) is formed, whereas the point in time t, is formed. A time point t, which has advanced by a predetermined time Δτ. At the timing of PT, it is magnetized upward and the conventional recording pattern PT
N@, PTN, an elliptical recording pattern P T N t larger than PTN by a predetermined amount. (Shown in white in Figure 3 (D))
is formed, thereby recording data SS? on the magneto-optical disk 4. It is designed so that it can be recorded.

Furthermore, as mentioned above, the value "1111" is set as the recording data S□.
01J recording pattern PTN&. and PTN,. Recorded data S□ is placed at the same position on the magneto-optical disk 4 where
When sequentially recording the value rlo0111J as
a, t2 tl, t! .

and rises at the timing of tst, time t, 4, t
Recording signal 5w5 where the peak value of th is larger by a predetermined amount ΔX
(31st!l(E)'') and supplies it to the semiconductor laser 14 of the optical pickup 13 via the laser drive circuit 12.

As a result, the value "1111" is set as the above-mentioned recording data S1.
On the recording patterns PTN&@ and PTN7° of 01J, the perpendicular magnetization film 3 of the magneto-optical disk 4 is exposed at time i! l,j
*A new elliptical recording pattern PTN&I that is magnetized downward at the timings of 'l, tss and tst.
(shown with diagonal lines in FIG. 3(F)) is formed, and at the timings t24 and txh, it is magnetized upward to create a new record with an oval shape larger than the conventional recording pattern PTN@, PTNI. Pattern PTN? I (3rd
A recording pattern P T N & of the magneto-optical disk 4 is formed. and P T
N? . New recording patterns PTN&l and PTN? corresponding to the recording data of 5 liters are shown above. It is possible to overwrite I.

The new recording pattern P T formed in this way
N & + and P T N 'r, the value "0" is first recorded at a predetermined position on the magneto-optical disk 4 on which the recording pattern PTN&+1 of the value rlJ is formed compared to the conventional case.
” recording pattern PTN? The unerased area AR, which occurs when , is formed. This makes it possible to practically eliminate the area of , which is the same point in time as when the value "1" was recorded! *Is
! N'%L 1%Si! Reproduction pulsed laser beam LP□ rises at the timing of fsLZ and t31
When a reproduced signal is obtained by sequential sampling (FIG. 3(G)), it is possible to prevent the possibility that noise will be mixed in and a reproduction error will occur.

According to the above configuration, the alternating current magnetic field H□ of a single frequency is applied to the magneto-optical disk 4, and the recording data SI
The alternating current magnetic field (according to T) is applied in a pulsed manner to the magneto-optical disk 4 at a timing when 1wt is near its maximum positive or negative value.
In a magneto-optical disk device 1 that records a set of record data on a magneto-optical disk 4 by irradiating a laser beam, the time point when the alternating current magnetic field 14w+ reaches its maximum positive value is tl,'3, depending on the set of record data. 'Ls, L'1s t,%...
A time t31 delayed by a predetermined period Δτ with respect to...
tts, tzs, to,,t! 9. The point in time when the AC magnetic field has the maximum negative value compared to the peak value of the pulsed laser beam L□ irradiated onto the magneto-optical disk 4 at the timing of ill, j! , t4, t6, tl, .
By selecting a large peak value of the pulsed laser beam LPw irradiated onto the magneto-optical disk 4 at the timings 4, tgi, tzs, . . . , the recording pattern of the magneto-optical disk 4 P T N h . and PTN? . Above is a new recording pattern PTN& according to the recording data set.
It is possible to realize a magneto-optical disk device 1 in which almost no unerased area AR1° is generated when overwriting is performed by forming 1 and PTNy+.

In this way, it is possible to easily realize a magneto-optical disk device l that can prevent the occurrence of reproduction errors due to unerased areas during reproduction.

(G4) Other embodiments (11) In the first and third embodiments described above, the peak value of the recording pulsed laser beam irradiated onto the magneto-optical disk at a predetermined timing near the negative maximum value of the AC magnetic field is , the alternating current magnetic field is set to a value larger than the peak value of the recording pulsed laser beam irradiated onto the magneto-optical disk at a predetermined timing near the maximum positive value by a predetermined amount ΔX, but the present invention is not limited to this. In a magneto-optical disk device that irradiates a magneto-optical disk with a pulsed laser beam at a predetermined timing near the maximum negative value of the AC magnetic field, the value may be set to a value larger by -Δχ.

Furthermore, instead of the peak value of the recording pulsed laser beam, the irradiation time of the recording pulsed laser beam may be different.
In short, recording that irradiates the magneto-optical disk with the energy of a pulsed laser beam at a predetermined timing when the alternating current magnetic field is near the maximum negative value, and irradiates the magneto-optical disk with the energy of a pulsed laser beam at a predetermined timing when the alternating current magnetic field is near the maximum positive value. If the energy of the pulsed laser beam is made to differ by a predetermined amount, the same effect as in the above embodiment can be obtained.

(2) In the second and third embodiments described above, the timing at which the AC magnetic field is delayed by a predetermined period from the timing at which the AC magnetic field reaches its maximum positive value and the timing at which the AC magnetic field reaches its negative maximum value are determined according to the recorded data. Although the magneto-optical disk is irradiated with recording pulsed laser light at a timing that is a predetermined period ahead of the timing, the present invention is not limited to this. The recording pulsed laser beam may be irradiated onto the magneto-optical disk at a timing when the alternating current magnetic field has advanced by a predetermined period and at a timing which is delayed by a predetermined period with respect to the maximum negative value of the AC magnetic field. Similar to the above embodiment, the phase timing of the recording pulsed laser beam irradiated onto the magneto-optical disk is arbitrarily selected according to the value of the recorded data so that the phase is not 180 degrees with respect to the frequency of the alternating current magnetic field. effect can be obtained.

(3) In the above-mentioned embodiments, a case has been described in which the application is applied to a magneto-optical disk device using a magneto-optical disk as a magneto-optical recording medium, but the present invention is not limited to this. It can be widely applied to magneto-optical recording and reproducing devices using recording media.

H Effects of the Invention As described above, according to the present invention, an alternating magnetic field having a single frequency is applied to a magneto-optical recording medium, and the alternating magnetic field has a positive or negative maximum value near the maximum value depending on the recorded data. In a magneto-optical recording and reproducing apparatus that records recorded data on a magneto-optical recording medium by irradiating the magneto-optical recording medium with a pulsed laser beam at a predetermined timing, the first invention provides a magneto-optical recording and reproducing apparatus in which the alternating current magnetic field is positive. The energy of the pulsed laser beam that is irradiated onto the magneto-optical recording medium at a predetermined timing near the maximum value when the alternating current magnetic field is negative, compared to the energy of the pulsed laser light that is irradiated onto the magneto-optical recording medium at a predetermined timing near the maximum value. By making the recording patterns different, the area of the unerased area is reduced when a new recording pattern is formed on the recording pattern formed on the magneto-optical recording medium in accordance with the recorded data and overwritten. .

Further, in the second invention, the timing is delayed by a predetermined period from the time when the AC magnetic field has a maximum positive value and by a predetermined period from the time when the AC magnetic field has a negative maximum value, depending on the recorded data. By irradiating the magneto-optical recording medium with pulsed laser light at advanced timing, a new recording pattern corresponding to the recorded data is formed and overwritten on the recording pattern formed on the magneto-optical recording medium. When doing so, the area of the unerased area is now smaller.

Furthermore, in the third invention, the energy of the pulsed laser beam irradiated onto the magneto-optical recording medium at a timing delayed by a predetermined period with respect to the point in time when the AC magnetic field reaches its maximum positive value, and A recording pattern formed on a magneto-optical recording medium by varying the energy of the pulsed laser light that is irradiated onto the magneto-optical recording medium at a timing a predetermined period has elapsed from the point when the magnetic field reaches its maximum negative value. When a new recording pattern corresponding to recording data is formed on top and overwritten, unerased areas are practically prevented from occurring.

In this way, it is possible to easily realize a magneto-optical recording and reproducing apparatus that can prevent the occurrence of reproduction errors due to unerased areas during reproduction.

[Brief explanation of the drawing]

FIG. 1 is a timing chart showing overwriting recording and reproducing operations according to an embodiment of the first invention, FIG. 2 is a timing chart showing overwriting recording and reproducing operations according to an embodiment of the second invention, and FIG. The figure is a timing chart showing overwriting recording and reproducing operations according to an embodiment of the third invention, FIG. 4 is a system diagram showing a magneto-optical disk device, and FIG. 5 is a timing chart showing conventional overwriting recording and reproducing operations. It is a chart. 1... magneto-optical disk device, 4... magneto-optical disk, 8... resonant circuit, 9...
・Oscillation circuit, 10...Clock generation circuit, 11
. . . Laser modulation circuit, 12 . . . Laser drive circuit, 13 . . . Optical pickup, LPW,
L□...Pulsed laser light, H,,,H,,1
......AC magnetic field, set...recorded data.

Claims (3)

[Claims] (1) An alternating current magnetic field having a single frequency is applied to the magneto-optical recording medium, and the alternating current magnetic field is applied to the magneto-optical recording medium at a predetermined timing near the maximum positive or negative value depending on the recorded data. By irradiating pulsed laser light on
In the magneto-optical recording/reproducing apparatus for recording the record data on the magneto-optical recording medium, the energy of the pulsed laser beam irradiated onto the magneto-optical recording medium at a predetermined timing when the alternating current magnetic field is near the maximum positive value; . A magneto-optical recording and reproducing apparatus, characterized in that the energy of the pulsed laser beam irradiated onto the magneto-optical recording medium at a predetermined timing near the maximum negative value of the alternating magnetic field is different. (2) Applying an alternating magnetic field having a single frequency to the magneto-optical recording medium, and applying the alternating current magnetic field to the magneto-optical recording medium at a predetermined timing near the maximum positive or negative value of the alternating magnetic field depending on the recorded data. By irradiating pulsed laser light on
In a magneto-optical recording and reproducing apparatus that records the recorded data on the magneto-optical recording medium, the timing is delayed by a predetermined period from the point in time when the alternating current magnetic field reaches its maximum positive value, and A magneto-optical recording and reproducing apparatus characterized in that the magneto-optical recording medium is irradiated with the pulsed laser beam at a timing when the alternating current magnetic field has advanced by a predetermined period with respect to the point at which the alternating current magnetic field reaches its maximum negative value. (3) Applying an alternating magnetic field having a single frequency to the magneto-optical recording medium, and at a predetermined timing near the maximum positive or negative value of the alternating magnetic field depending on the recorded data, By irradiating pulsed laser light on
In a magneto-optical recording/reproducing device that records the recorded data on the magneto-optical recording medium, the alternating current magnetic field is set at a timing delayed by a predetermined period from the time when the alternating current magnetic field reaches its maximum positive value, depending on the value of the recorded data. The energy of the pulsed laser beam irradiated onto the magneto-optical recording medium and the pulsed laser beam irradiated onto the magneto-optical recording medium at a timing advanced by a predetermined period with respect to the point in time when the alternating current magnetic field reaches its negative maximum value. A magneto-optical recording and reproducing device characterized in that the energies of laser beams are different.