JPH03162748A - Magneto-optical recorder - Google Patents

Abstract

PURPOSE:To prevent a fluctuation of impressing magnetic field intensity of a magnetic field generating device upon a magneto-optical recording information carrier at the time of recording information by holding information of a regenerative signal for a signal recorded with a different intensity light beam in a prescribed position of the magneto-optical recording information carrier to a holding circuit and recording a data signal with a light beam of corresponding intensity. CONSTITUTION:Reflected light from the magneto-optical recording information carrier 11 is detected by an optical head 31 and converted into a regenerative signal, and the regenerative signal amplified by an amplifier 32 is detected in its max. level by an AM detecting circuit 33. Then, a max. value is detected from the signal level by a max. value detecting circuit 34, and also a position in a test signal recording area of the information carrier 11 is obtained and specified, and then this information is sent to a recording level value holding circuit 35. Afterward, a code corresponding to the detected max. value is converted into an analog signal by a D/A converting circuit 36 and given to an output level control terminal of an ALPC 37, and a signal to be recorded is recorded at an optimum level to the information carrier 11. By this method, the impressing magnetic field intensity of the magnetic field generating device 18 can be prevented from fluctuating.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a magneto-optical recording device for recording information on a magneto-optical recording information carrier (magneto-optical disk). Magneto-optical recording information Il! has a so-called optical modulation overwrite function that allows new information to be written directly to the memory.
Concerning information recording methods on carriers. [Prior Art] The present inventors have previously proposed a magneto-optical recording information medium having an optical modulation overwrite function, namely a magneto-optical disk and a magneto-optical recording device, in the invention of Japanese Patent Application No. 1-119244. ．． The magneto-optical recording information carrier and magneto-optical recording device according to the present invention are briefly as follows. "A first magnetic layer having perpendicular magnetic anisotropy; and a second magnetic layer provided on this eleventh! magnetic layer, having perpendicular magnetic anisotropy, and coupled to the first magnetic layer by exchange force. In the second &i-type layer, the magnetization is maintained in a constant direction without reversing the magnetization during recording and reproduction of (al), and satisfies [blTc.<Tel (ClHe,>H at room temperature). A magneto-optical recording information carrier characterized by satisfying Hcl>Hwt+Hb, Hcl>Hwt+Hb.
A magneto-optical recording information carrier in which the magnetization direction of one layer is in a constant direction and the magnetization does not reverse during recording and reproduction, a beam emitting element that irradiates this magneto-optical recording information carrier to record and reproduce information, and the beam termination element. A magneto-optical recording device equipped with a magnetic field generator that applies a magnetic field in a fixed direction to a portion of a magneto-optical recording information carrier that is irradiated. ” A more detailed explanation will be given below with reference to the drawings. Figure 10 (
8) is a schematic diagram showing the external appearance of the magneto-optical recording information carrier proposed in the invention of Japanese Patent Application No. 1-119244 mentioned above, as well as the structure of the main parts of the magneto-optical recording device for recording information on the carrier. , ℃》 is a partial sectional view along the circumferential direction of the magneto-optical recording information carrier showing the state of optical recording and reproducing on the magneto-optical recording information carrier, and IC) is a partial cross-sectional view along the circumferential direction of the magneto-optical recording information carrier showing the power change of the laser beam for information recording on the magneto-optical recording information carrier. This is a graph showing the characteristics of. Figure 10(a). (In bl, l1
is a magneto-optical recording information carrier; 20 is a magneto-optical recording information carrier 11;
The laser beam 16 from the beam emitting element for recording and reproducing information is focused by the objective lens 5 to form a magneto-optical recording information carrier l1.
This is the beam spot irradiated. Summer 8 is the laser beam 20 of the magneto-optical recording information carrier II.
This is a magnetic field generator that generates a magnetic field in which the magnetic field applied to the irradiated area is oriented in a fixed direction. 2 is a substrate made of glass or plastic. 13 is a first magnetic layer, which is laminated on the substrate 2 and has perpendicular magnetic anisotropy. Reference numeral 14 denotes a second magnetic layer, which is aNed to the Im-type 7113, has perpendicular magnetic anisotropy, and is coupled to the first magnetic layer 13 by exchange force, so that the magnetization does not reverse during recording and reproduction. It is kept oriented in a certain direction. 7 is the information recorded in the lm-th property Nl3, and the magnetization direction of the first magnetic layer l3 is the lO-th figure t.
In this case, the upward part on bl is “l” of the binarized data.
The area is shown as . The first magnetic layer l3 and the second magnetic layer l4 are Tc, < ”
l”c, (where Tc. and Tc. are respectively the first magnetic J
! 13. Chierly temperature of the second magnetic layer) and l{ at room temperature
c 1 > il w 1+Hb. HCI>Hw=
+Hb (however, Hc+ and Hct are respectively the first magnetic layer 1
3. Coercive force of the second magnetic layer near room temperature, HI1+
+ Hwx are the first magnetic layer 13. The exchange coupling force of the second magnetic layer near room temperature, Hb, is the magnetic field generator 18
For example, this relationship is expressed in the combination of rare earth metals and transition metal alloys. In addition, to perform so-called light modulation direct overwrite,
It is necessary to control the intensity of the laser beam 20 from the beam emitting element to at least three levels: high, medium, and low. Among them, in 2{a of a pulse beam with a high level of laser intensity and a pulse beam with an intermediate level of laser intensity, when the magnetic layer other than the magnetic layer that does not cause magnetization reversal is at a high level,
Either a pit with upward magnetization or a pit with downward magnetization is formed, and the other pit is formed when it is at a medium level. Information is then read using a low-level laser beam. Next, we will explain the operation. The magneto-optical recording information carrier 1l is rotated in the direction of arrow a in the figure. As mentioned above, the magneto-optical recording information carrier 11 has two magnetic layers 13. 14, the substrate 2, the first magnetic layer 13 . This is the second Vi layer 14. Here the first
The magnetic layer 13 is a recording layer for holding the magnetization orientation representing information 0" and "1", and is also a readout layer, and the second magnetic layer 14 is provided to perform an overwrite function. The second magnetic layer l4 is also called an initialization layer and has a function of 4l!, which functions as a conventional auxiliary layer and an initialization magnet.Here, the characteristics of the first magnetic layer l3 and the second magnetic layer 114 are , whose Curie temperatures are Tc1 and Tcg, respectively, T
There is a relationship: c,<'rl:, and each coercive force is expressed as Hc. Hc
When the exchange coupling force of both layers is Hi(1-1.2), the following relationship exists. He, > HM, + Hb...(1) Hc
@> l{M. + Hb - (21 Equation +11 is effective at a temperature between room temperature and a certain temperature T. lower than Tc. That is, in the temperature range between room temperature and T.
The coercive force He. of the magnetic layer l3. is the shadow of the exchange coupling force 'IiHH
1 and the applied magnetic field Hb from the magnetic field generator rt1B during recording, which means that it is possible to maintain the magnetization direction representing recorded information without being influenced by the magnetization direction of the second ift property 7114. do. Equation (2) holds true throughout the operating condition range. That is, within the range of operating conditions, the coercive force He. is larger than the sum of the shadow of the exchange coupling force 1pHw= and the magnetic field Hb applied by the magnetic field generator 1B during recording. Therefore, once the second magnetic layer 14 is initialized, for example, the 10th
If the magnet is initialized upward as shown in Figure (b), the magnetization will not be reversed and the upward magnetization state can be maintained. First, a case where information recorded on the first magnetic field 113 is repopulated will be explained. As shown in FIG. During reproduction, the first magnetic layer l3 is irradiated with a beam spot l6, and the magnetization direction of the irradiated portion of the first magnetic layer 13 is converted into optical information by the conventionally well-known optical Kerr effect, thereby creating a magneto-optical recording information carrier. 11. At this time, the laser intensity irradiated to the magneto-optical recording information carrier l1 is an intensity corresponding to point A in the graph of FIG.
At this intensity, the IWl of the irradiated part of the beam
The maximum temperature rise of the magnetic layer 13 and the second magnetic layer 14 is the Curie temperature Tc of the first magnetic layer 13 and the second magnetic layer 14,
, it does not reach Tc. Therefore, beam spot 16
Magnetization information is not erased by irradiation. 1st magnetic F! The characteristics of the temperature change of the reversal magnetic field of No. 13 are
The graph in Figure 12 shows the relationship between the intensity of the laser beam of the magneto-optical recording information medium and the temperature change of the magnetic film within the laser substrate 7, respectively. The reversal magnetic field is the minimum required magnetic field to reverse magnetization, and is given by HC+-Hwl. Figure 1O (In Cl, laser intensity (power) is R+
The solid line in FIG. 11 shows the temperature change of the reversal magnetic field when the laser intensity is R. Each case is indicated by a dashed line. First, a recording operation when recording information "O", that is, when the magnetization direction of the first magnetic layer 13 is directed downward, will be explained. When the laser beam 20 of intensity R1 is irradiated, the temperature inside the beam pants 6 rises to "rr+" in FIG.
Then, when the disk rotates and the laser beam 20 is no longer irradiated onto the beam spot 6, the l iff characteristic layer 1
The temperature of 3 falls. As can be seen from the solid line in FIG. 11, Hb > Hwl-Hc, in the entire temperature range between Tc+ and room temperature, so the magnetization direction of the 1st & 11th element 1113 is! 11
A world has emerged! The direction of the magnetic field generated by a '1 1 8, that is, the bias magnetic field Hb, is downward. Next, when recording the news “l゜”, that is, the first magnetic first raw layer 13
We will explain the recording operation when the magnetization direction is directed upward. Strength R. When the laser beam 20 is irradiated, the temperature within the beam spot 16 rises to Tro as shown in FIG. Then, when the disk rotates and the beam spot l6 is no longer irradiated with the laser beam 20, the temperature of the first magnetic layer 13 drops. As can be seen from the broken line in FIG. 11, for example, around temperature T9, Hbl<Hga1-Hc. Therefore, the magnetization direction of the first magnetic JI 13 is upward, which is the direction in which the exchange force acts, that is, the magnetization direction of the second magnetic layer 14. Through the above-described operation, during overwriting, the laser beam intensity is changed to intensity R1 and intensity R. corresponding to each point C and H in FIG. If the intensity is modulated to At the intensity corresponding to this point A, the maximum temperature rise of the first magnetism J!13 and the second magnetism N14 of the beam spot 16 is the Curie temperature Tc. of the first magnetism N13 and the second magnetism 71!114. Tc.
It does not reach. Therefore, the magnetization direction, that is, the recorded information will not be erased by the irradiation with the beam ribbon 16. Next, the laser intensity is R. In the case of R1 and the case of R1, the 11th
As shown in the figure, the reason why the temperature change of the reversal magnetic field of the first magnetic layer l3 differs as shown by the solid line will be explained. By laser irradiation, both magnetic layers 13. 14, the temperature rises in both cases, but the subsequent heat dissipation rate is higher in the first magnetic layer l3 than in the second magnetic layer l3.
Greater than 4. This is according to Rizan below. Since the (+) laser beam 20 is irradiated from the first magnetic JW 13 side, the highest temperature of the first magnetic JW 13 is the same as that of the second magnetic JW 13.
Magnetic layer! It is higher than that of 4, so the heat dissipation rate is also faster. (ii) The first magnetic M13 is in contact with the substrate 2, and the first magnetic M13 is in contact with the substrate 2.
Heat is radiated through. (iii) The thickness of the first magnetic layer 13 is extremely thin, and therefore the amount of heat dissipated is large. In this way, the heat dissipation rate of the first magnetic Jil3 is higher than that of the second magnetic Nl4. Strength R. laser beam 2
0, the temperature of the first magnetic layer 13 becomes Tr. After that, the temperature of the first magnetic layer l3 increases to ? T in figure 1
Let Tzre be the temperature of the second Mi Jil4 at the time when it drops to around p. Further, after the temperature of the first magnetic Nl3 rises to Tr in FIG. 11 by the laser beam 20 with the intensity R1, the temperature of the first lift Jil3 increases to
If the temperature of the second magnetic Jlil4 at the time when it drops to around p is T■rl, then T lrl < T lrl due to the difference in heat dissipation rate mentioned above. That is, when the laser beam 20 with a large intensity R is irradiated, the temperature of the second magnetic layer [14] becomes higher when the temperature of the first magnetic layer 13 is around 'rp. Considering that the exchange coupling force tends to decrease as the magnetic layer becomes hotter, the exchange coupling force becomes smaller when irradiated with the laser beam 20 having a large intensity R1. Therefore, there is a difference between the solid line and the broken line in the temperature change of the reversal magnetic field of the first magnetic layer l3 in FIG. 11. This causes hysteresis in magnetization with respect to temperature, making overwriting possible. “Example 1” The magneto-optical recording information carrier 11 is prepared by depositing, for example, a first magnetic M 13 : Tbt3FetzCos (
Film thickness SOO) 2nd G4i N14: Gd+4Tb
It is obtained by sequentially laminating ferrimagnetic materials of +nC (its film thickness), and the magnetic layers are connected by exchange force. has a magnetization reversal magnetic field of 1 kOe or more from room temperature to 250°C, and the second magnetic layer does not cause magnetization reversal within the operating temperature range.
When the exchange force becomes larger than the coercive force, and the difference between the exchange force and the coercive force is the largest, the difference is expressed as the magnetic field lko
It is about e. The magnetic field generator 1B always generates a magnetic field of approximately 1 kOe in a fixed direction. The second magnetic recording information barrier 11 is exposed to a magnetic field greater than or equal to the reversal magnetic field of the second magnetic layer 14 to generate a second magnetic layer 1'.
! 14 is first uniformly magnetized only once, for example, in an upward direction. At this point, the direction of the magnetic field generated by the magnetic field generator l8 is upward, and the first magnetic layer 13 and the second magnetic layer Jl5
14 has the above-mentioned relationship. In the magneto-optical recording information carrier 11 configured as described above, optical modulation direct overwriting is possible by modulating only the laser intensity through the above operation. Specifically, the focus length is 0.8 to 5 at a linear speed of 5 m/sec.
The magnetic field generated by the magnetic field generator 18 is 10,000 μm signal.
e. The laser power was optically modulated to a peak power of 16 Kakuichi and a bottom power of 5 Ichiga, respectively, and a characteristic with an extinction ratio of 25 dB or more was obtained. Laser power during playback is 1.5mW
I went there. "Examples 2 to 8" It is sufficient that the coercive force of the second magnetic layer l4 is sufficiently large near the Chierly temperature of the first magnetic layer l3. Similarly to 1, various magneto-optical records as shown in Table 1 are used. When using the magneto-optical recording information carrier shown in Table 1 and at a linear velocity of 6 ml sec, the light is recorded as shown in Table 2. Except for modulation, the same procedure as in "Example 1" was carried out, and characteristics of an erasure ratio of 20 dB or more and an optimum power of about 23 to 35 dB were obtained.
Light modulation direct overwriting similar to "Example 2" was possible. Table 2 "Example 9" As yet another example of the magneto-optical recording information carrier, an amorphous alloy of a transition metal and a rare earth metal exhibiting ferrimagnetism is suitable, such as lm-th NTb. Fe&ffCOl@ (Membrane J'!
500 people) Second magnetic layer (:d+zTb+tCOti
(v. Thickness: 1500 A) Good overwriting can be achieved in the same manner as in ``Example 1'' with the combination of assembly and film thickness. Note that each magnetic layer is made of DyPeCo, TbCo
, TbFe/GdCo, GdDyCo, TbDyC
The second magnetic layer l4 and the first magnetic layer 11 may be made of a ferrimagnetic material such as o, DyCo, etc., and the magnetization does not reverse in the operating region.
The magneto-optical recording information carrier 11 may include a magnetic layer in which 13 and 13 are involved only near room temperature.
A dielectric layer may be included to reduce oxidation corrosion of the magnetic layer. FIG. 13 is a schematic diagram showing the configuration of the optical system of the above-mentioned magneto-optical recording device. In the figure, ■! is the aforementioned magneto-optical recording information TG carrier, and the laser beam 20 emitted from the beam emitting element 3l passes through the collimating lens 32. The beam is irradiated through a beam splinter 33 and an objective lens 34. The reflected light of the laser beam 20 on the magneto-optical recording information carrier 11 passes through the objective lens 34 and reaches the beam splitter 33, where the direction is changed by 90 degrees and passes through the A wavelength plate 35 and the beam splinter 36 to the tracking servo. At the same time as reaching the river detector 37, a portion of the light is changed in direction by 90 degrees by the beam splinter 36, passes through the condensing lens 38, and reaches the focusing servo detector 39. FIG. 13 fbl is a schematic diagram showing a configuration for extracting a reproduced signal from the magneto-optical recording information carrier I1 using the above-mentioned optical system. That is, the detection signal ε of the tracking servo detector 37 is input to one terminal of the operational amplifier 40, and the detection signal of the force-singing servo detector 39 is input to the ten terminal of the operational amplifier 40. For the purpose of further improving the information recording ability of the above-mentioned magneto-optical recording information carrier having two magnetic layers, they filed a patent application for a magneto-optical recording information carrier having a magnetic layer of 3N or more. It was published as No. 1-154918 or Japanese Patent Application No. 1-1175591.
The invention of Japanese Patent Application No. 1-154918 regarding a magneto-optical recording information carrier having three magnetic layers is briefly as follows. "A first magnetic layer having perpendicular magnetic anisotropy, a second magnetic layer provided on the first Kt layer and coupled to the first magnetic layer by exchange force."
a magnetic layer, a third magnetic layer provided on the second ifi layer and coupled to the second magnetic layer by exchange force; Tct < TCt < Tc3, where Tc. :Curie temperature Tcl of the first magnetic layer
: Curie temperature of the second magnetic layer Tc3: Satisfies the Chierie temperature of the third magnetic layer and at room temperature HC+ > Hbh lH+ Hc3 > H@s+
and Hew<H between room temperature and Tc+
wits+ H@tu+ <However, Hc. : Coercive force of the first magnetic layer, He. : Coercive force of the second magnetic layer, Hc3: Coercive force of the third ffi layer, Hwi(j): The temperature that satisfies the shift amount of the switching magnetic field of the i-th layer due to the exchange coupling force acting between the j-th and the 11-th It is characterized by the fact that it exists. Also,
The invention of Japanese Patent Application No. 1-1175591 regarding a magneto-optical recording WJ carrier having a 4N magnetic layer is briefly as follows. "A first magnetic layer having perpendicular magnetic anisotropy; a second magnetic layer provided on the first magnetic layer and coupled to the first magnetic layer by exchange force; a second magnetic layer provided on the second magnetic layer having the first magnetic layer; a third magnetic layer coupled to the third magnetic layer by exchange force; .Tc.<Tca.T
c<Tea However, Tc+: Curie temperature of the III-th layer Tc.
: Curie temperature of the second magnetic layer Tcz: Curie temperature of the third magnetic layer Tc4: Satisfies the Curie temperature of the fourth magnetic layer and at room temperature Hc+ > Hw+ +x++ Hca> HHa+s
+ and from room temperature T c. and Tc. HCz < HID(ff) HIDl1), H
C3< Hws+a+ Hw. 1 wealth》. However, Hc. :First! Coercive force of the fi layer, Hc@: Coercive force of the second magnetic layer, Hc3: Coercive force of the third fff layer, Hca: Coercive force of the fourth Mi layer, Hwi(j): Between the j-th layer and the i-th layer The characteristic is that there exists a temperature that satisfies the shift amount of the reversal magnetic field of the IN-th due to the exchange coupling force acting on the magnetic field. 14th
The figure shows magneto-optical recording information with three magnetic layers! ■It is a schematic diagram to show the body posture and its movements. In FIG. 14, 24 is the first magnetic layer. 25 is a second magnetic layer, and 26 is a third RDI layer. The rest is the same as Figure 1O. Each magnetic layer is composed of a transition metal-rare earth alloy,
Furthermore, both layers are ↑H rich. The first magnetic layer 24 and the second magnetic N25 are coupled by exchange coupling force, and this exchange coupling force acts to equalize the direction of TM sublattice magnetization in both layers. Second magnetic J! 25 and the third magnetic N26 are also coupled by the same exchange coupling force. Further, the magnetization of the third magnetic Ji 26 is initialized upward in advance in FIG. 14 by an electromagnet or the like. First magnetic N24
is the sublattice magnetization representing the signals “0” and “l” (here ↑
This is a recording layer for retaining the M sublattice magnetization), and the second
The magnetic layer 25 and the third magnetic layer 26 are provided to exhibit overwrite ati. In particular, the second magnetic layer 25 is called an auxiliary layer, and the sublattice magnetization direction of the second magnetic layer 25 is transferred to the lift property [24], that is, the first magnetic layer 24
The sublattice magnetization direction is the second! Utilizing the fact that the ft property is aligned with that of FJ25, it is possible for the first magnetism [24] to have a desired magnetization direction. Further, the third magnetic layer 26 is an initialization layer, and by utilizing the fact that its sublattice magnetization direction is transferred to the second magnetic layer 25,
This makes it possible to align the sublattice magnetization direction of the second magnetic layer 25 in a constant direction at room temperature. Each magnetic! 24.25
．． The characteristics of 26 are as follows. The Chierly temperature of each layer is Tct. If Tex, Tcs, then Tc+ < Tc, < Tc3. Furthermore, since all three layers are TM lynch, the following conditions must be met at room temperature. Hc+-Hw++t+〉O'...《3》H
cs Hb HI13 +t) > O −
151 There is a temperature between room temperature and Tc that satisfies the following conditions. Hcg+ Hwzn+ Hottext < O −
+41 Here, Hci: Coercive force of the first layer Hwi (j): Shift of the reversal magnetic field of the i-th layer due to the exchange coupling force acting between the j-th layer and the first Hb: Magnetic field generator (bias magnet ) The second magnetic layer 2 is applied between the second magnetic layer 25 and the third magnetic layer N26 of the magneto-optical recording information carrier having three magnetic layers.
If one or more magnetic layers having a Curie temperature lower than that of 5 are provided, more stable recording/reproduction becomes possible, and it is also possible to improve the C/N ratio of the reproduced signal. FIG. 15 is a schematic side sectional view showing the structure of such a magneto-optical recording information carrier having four magnetic layers. In FIG. 15, 27, 28, and 29 are the second magnetic layers. These are the third magnetic layer and the fourth magnetic layer. Here, the third magnetic JW28 is a newly provided layer, and the fourth magnetic J!
29 is the third magnetic J! of the magneto-optical recording information carrier having the aforementioned 3N magnetic layer. It corresponds to 26. A magneto-optical recording information carrier having such a 4JW magnetic layer is a glass-based Fi. 2
For example, using the span method, etc., Im magnetic layer: DyxJeoCOw 500 [Compensation composition (room temperature)] Second magnetic Ji: Tbl5FeoCo+s 700 (RE rich) Third magnetic 7I: Tb+iFe*a
200 people (TM Lynch) Fourth magnetism [1: Tb
s*Cots 700 people [R[! Each magnetic layer is coupled to the adjacent magnetic layer by exchange force. Note that RE Lynch indicates that the rare earth metal sublattice magnetic moment is predominant, and TM Lynch indicates that the transition metal sublattice magnetic moment is predominant. The fourth magnetic layer 29 has a temperature of 70° C. from room temperature to about 300° C.
It has a coercive force of 0 0 e or more, and the two fourth magnetic layers do not undergo magnetization reversal within the operating range when the temperature rises due to laser beam irradiation. ? The 2nd ■1 Mori layer 27 has a guaranteed temperature above room temperature. The magnetic field generator l8 generates a magnetic field of 200 to 4000 e. The fourth magnetic layer 29 is first uniformly magnetized only once, for example, upward, by exposing the four magneto-optical recording information bodies to a magnetic field greater than the magnetization switching field of the fourth magnetic WJ 29. On this occasion,
The magnetic field generated by the magnetic field generator 18 is generated in two directions. The temperature characteristics of each layer and the magnetic characteristics between each layer are as follows. Tca>TC! > TCI > Tc= > (
room temperature) − Hw, (1) + Hc+ − Hb >
(Room temperature) 11w+tz+ Hc+ l-1b>
(Reference temperature: a certain temperature from room temperature to Tc+) Hwtt3, H-■. +Hcg+Hb > (room temperature)H
w4t3, + HC4> O (all operating temperature ranges) 4J like this! The recording operation of a magneto-optical recording information carrier having a magnetic layer is as follows. During reproduction, the laser output is increased and the part inside the focused spon [6 exceeds the reference temperature, the magnetization reversal temperature of the second magnetic layer 27, that is, the magnetization holding force becomes smaller than the external magnetic field, and the magnetization direction is reversed in the direction of the external magnetic field. If the temperature does not reach that temperature, TM and R of the second magnetic layer 27
The sub-elliptic magnetization direction of E does not change, and the first magnetic layer M24 is at the reference temperature and the magnetization direction of the second &t magnetic layer 1i27 is the same as that of the first magnetic layer 24.
The magnetization direction of the TM sublattice of the first magnetic Ji 24 is directed downward as shown in FIG. 16 (111). At the reference temperature, the first magnetic layer 24 is TM-rich ("
0° record). At this time, the third magnetic layer 28. Fourth magnetic layer 29
has no particular contribution to the operation, and the third! Even if the magnetization of the f1 layer 28 disappears, it is magnetized again in the same direction due to the exchange force with the fourth Mi layer 29. After this, the condensing spont l6 is removed, and the first magnetic layer 24 is cooled to about room temperature and returns to the guaranteed composition. If the magnetization reversal temperature of the second magnetic layer J127 is exceeded but the magnetization reversal temperature of the fourth magnetic layer 29 is not reached, the first magnetic [24, third magnetic J528
The magnetization of the fourth magnetic layer 29 disappears, but the sublattice magnetization direction of the fourth magnetic layer 29 does not change. Also, since the temperature exceeds the guaranteed temperature of the second magnetic layer 27, the temperature of the second magnetic layer 27 is higher than the temperature shown in FIG.
I have become M-rich. At the magnetization reversal temperature of the second magnetic layer 27, the magnetization direction of the second magnetic layer 27 is directed upward as shown in FIG. and further the second magnetic layer 2
The magnetization direction of 7 is transferred to the first magnetic layer 24, and the 6R direction of the first magnetic layer 24 becomes upward. The first magnetic layer 24 and the second magnetic layer 27, the second magnetic P! 27 and the third magnetic layer 28, and the third magnetic layer 285 and the fourth magnetic layer 29, the third magnetic layer 2
8 is below the Curie temperature, the sublattice magnetization direction of the third magnetic layer 28 is aligned with the fourth magnetic layer 29 as shown in FIG. 16 (5),
When the temperature further decreases and the exchange force increases, the second
Magnetic J? The sublattice magnetization direction of il27 is aligned with the sublattice magnetization direction of the fourth magnetic layer 29 via the third magnetic layer 28, and
The initial state is restored as shown in Figure (6). Through the above operations, optical modulation direct overwriting is achieved by modulating only the laser beam intensity in the magneto-optical recording information Ig carrier having a 4N magnetic layer. [Problem to be Solved by the Invention] By the way, when using the magneto-optical recording information carrier as described above, if the distance between the magnetic field generating device and the magneto-optical recording information carrier changes during recording of information. , when that information is reproduced, the reproduction signal level may fluctuate, leading to erroneous reproduction. For example, as a former prisoner whose distance fin between the magnetic field generator and the magneto-optical recording information body fluctuates, Surface wobbling occurs because the magnetic recording information carrier is not perfectly flat, or because the optical recording information carrier l1 is not correctly mounted on the rotating shaft (not shown). Furthermore, there is a possibility that the reproduced signal level may fluctuate due to subtle differences in the magnetic properties of individual magneto-optical recording information media. The present invention was made in view of these circumstances, and
Fluctuations in the magnetic field intensity applied by the magnetic field generator to the magneto-optical information carrier during information recording on the magneto-optical information carrier or differences in the magnetic properties of individual magneto-optical information carriers affect the reproduction of information. The purpose of the present invention is to provide an optical recording device that can avoid such problems. (Means for Solving Problem Ll) The first aspect of the present invention is to determine the maximum level of a reproduced signal of a signal recorded at a predetermined position of a magneto-optical recording information carrier using light beams of different intensities. The signal is held in a holding circuit, and a signal is recorded with a light beam of a corresponding intensity.The second invention is a signal recorded at a predetermined position of a magneto-optical recording information carrier with a light beam of a successive intensity. The sick minimum value of the reproduced signal is held in a holding circuit, and the signal is recorded with a light beam of intensity corresponding to this.The third invention provides an inverted signal of the tracking error signal to the control circuit, and The fourth invention is to control the maximum level of the reproduced signal ε of the signal fε recorded at a predetermined position of the magneto-optical recording information carrier under different magnetic field intensities. The jitter of the reproduced signal of the signal recorded at a predetermined position of the magneto-optical recording information carrier under different magnetic field intensities is maintained in a holding circuit and the magnetic field generating device is controlled accordingly. The minimum value of is held in a holding circuit, and the magnetic field generator is controlled in accordance with this.
The output signal of the inversion circuit is given to the magnetic field strength generation circuit, and the magnetic field generation device is controlled accordingly. [Operation] In the first aspect of the present invention, the maximum level of the reproduced Is number of the IS number recorded at a predetermined position of the magneto-optical recording information carrier with light beams of different intensities is held in the holding circuit. , a signal is recorded with a light beam of corresponding intensity. In the second invention, magneto-optical recording information fIIi! ! The minimum jitter value of the reproduced signal of the signal recorded at predetermined positions on the body using light beams of different intensities is held in a holding circuit, and the signal is recorded using light beams of the corresponding intensities. In the third invention, an inverted signal of the tracking error signal is given to the control circuit, and the intensity of the light beam is controlled accordingly. In the fourth invention, the maximum level of the reproduced signal of {No. The generator is controlled. In the fifth invention, the minimum value of the jitter of the reproduction signal No. 13 recorded at a predetermined position of the magneto-optical recording information Ig carrier under different magnetic field intensities is held in the holding circuit, and the magnetic field is The generator is controlled.
In the sixth invention, the output ε of the inverting circuit is given to the magnetic field strength generating circuit, and the magnetic field generating device is controlled accordingly. [Embodiments of the Invention] Hereinafter, the present invention will be described in detail based on drawings showing embodiments thereof. FIG. 1 shows the relationship between the magnetic field strength (wL axis) of the magnetic field generator 18 applied to the magneto-optical recording information carrier l1 during information recording and the level of the reproduced signal. In this case, the power P read of the laser beam projected onto the magneto-optical recording information carrier 11 for signal reproduction is constant fmW,
Laser power P for information recording. 9. 10, 1
There are three types: 1■1. For example, magnetic field generator l
If the magnetic field strength of 8 is 1000 0 e, then 10
It is desirable to record information with a laser power of m-. However, if the distance between the magnetic field generator l8 and the magneto-optical recording information carrier l1 increases due to surface runout, for example, and the magnetic field strength applied to the magneto-optical recording information carrier ll decreases to 9500e, the laser power By recording with 11-, it is possible to avoid a drop in the playback signal level. Conversely, if the magnetic field strength applied to the magneto-optical recording information carrier 11 increases to, for example, 10500 e, it is possible to avoid a drop in the level of the reproduced signal by recording with the laser power set to 9-. It becomes possible. In order to utilize the above principle, in the magneto-optical recording device of the present invention, a test signal recording area is set in a specific area of the magneto-optical recording information carrier 11. Then, a test signal is recorded in this test signal recording area, the recorded test signal is reproduced, and a signal recording condition that provides the optimum, that is, the maximum reproduced signal level, is detected. FIG. 2 is a block diagram showing an example of the structure of a magneto-optical recording device according to the present invention. In the figure, reference numeral 31 denotes an optical head, which detects the reflected light from the magneto-optical recording carrier 11 of a reproduction laser beam irradiated from a laser diode 38, which will be described later, and converts it into an electrical signal, that is, a reproduction signal. The reproduced signal output from the optical head 31 is amplified by a single width amplifier 32 and sent to a static detection circuit 33.
is given to. ^M detection circuit 33 receives the reproduction signal ε given from the amplifier 32.
The level of the reproduced signal is detected by moxibusting the signal, and the maximum value of the levels of the reproduced signal is detected. The maximum value detection circuit 34 detects the magneto-optical recording signal carrier 1 on which the reproduction signal of the maximum level detected by the AM detection circuit 33 has been recorded.
The optimum recording level is detected by detecting the test fε recording area of No. 1. In the recording level value holding circuit 35,
A code indicating the optimum recording level detected by the maximum value detection circuit 34 is held and output to the D/A conversion circuit 36. The D/A conversion channel 36 converts the code given from the recording level value holding circuit 35 into an analog signal. 37 is A
This is an LPC (automatic laser power control circuit), and the output of the D/A conversion circuit 36 is applied to its output level control terminal, and a signal representing information to be recorded is input to its signal input terminal. Then, the LPC 37 converts the pulse signal input to the No. 13 human power terminal to the level input to the output level control terminal, and drives the laser diode 38 according to this pulse signal. 38 is a laser diode whose emission is controlled by ALPC37. The operation of the magneto-optical recording device of the present invention, which has been widely used in this way, is as follows. First, for example, when the magneto-optical recording information carrier 1l is installed in the device, a signal representing the level of a pulse signal is sent to the output level control terminal of the LI'C37, and a predetermined pulse signal is sent to the g input terminal. input. At this time, by changing and controlling the signal input to the output level control terminal in several stages, the signal recorded on the magneto-optical recording information carrier 11,
In other words, the test number S is as shown in Figure 3.<Level (Pulse height)
becomes a different pulse signal. Such a test signal is converted from an electrical signal by a laser diode 38 into a laser beam having a power corresponding to the level thereof, and is installed in the innermost trunk 110 of the magneto-optical recording information body 11, for example, as shown in FIG. The test signal is recorded in the test signal recording area. After the test signal is recorded, the laser diode 38 irradiates the test signal recording area of the magneto-optical recording information carrier l1 with a laser beam having a power for reproducing the signal. The reflected light from the magneto-optical recording information carrier l1 is detected by the optical head 3l, converted into an electric signal as a reproduction signal, and amplified by the amplifier 32. amplifier 32
The reproduced signal amplified by ^H detection circuit 33^
The MJ eclipse wave is detected, its level is detected, and the maximum level is detected. The maximum value detection circuit 34 determines the position in the test signal recording area of the information carrier 11 where the maximum level of the reproduced signal detected by the ^H detection circuit 33 is detected, and specifies the test signal recorded at that position. , the code at that level is sent to the recording level value holding circuit 35 as the optimum recording level. Thereafter, when recording actual signals, the optimum recording level code held in the recording level value holding [i71 path 35 is converted into an analog signal by the 0/^ conversion circuit 36 and applied to the output level control terminal of the ALPC 37. Also, since the signal to be recorded is given to the input terminal A ε of the LPC 37, the signal to be recorded is recorded on the magneto-optical recording information carrier l1 at the transmission level. FIG. 5 is a block diagram showing an example of the second invention of the magneto-optical recording TJ1 device of the present invention. In the figure, 31 is the same optical head as before, and the error signal S[! is output to the amplifier 40. The amplifier 40 receives the error signal SE output from the optical head 31.
is amplified and fed to the inverter 4l. Inverter 4! gives the inverted fS signal SE of the error iε signal SE to the output level control terminal of the ALPC37. ^LPC 37 and laser diode 38 are the same as those in the first invention shown in FIG. 2 above. The operation of the magneto-optical recording t1 device of the second invention is as follows. When the magneto-optical recording information carrier l1 is installed and signals are being recorded and reproduced, the magneto-optical recording information +a t
If there is surface wobbling in the O-body 11, the distance between the magneto-optical recording information carrier 11 and the magnetic field generator l8 changes. However, if a signal is recorded in a state where there is vibration, the level of the reproduced signal will fluctuate (decrease).Also, if a normally recorded signal is reproduced in a state with surface vibration, the reproduction level will still fluctuate. (
descend. In such a case, the error signal SE for the focus servo is proportional to the surface runout of the magneto-optical recording information carrier 11. Therefore, when a signal SE with the opposite polarity of the error signal SH for focus servo is applied to the output level control '4n terminal of the ^LPC 37, the level of the output signal of the ALPC 37 is proportional to the amount of surface runout of the magneto-optical recording information carrier 1l. It increases. By performing such control, it is possible to record and reproduce signals in optimal conditions both during recording and reproduction. By the way, what is important when actually reproducing a signal from the magneto-optical recording information carrier l1 is how to minimize the jitter in the reproduced signal. As a third aspect of the magneto-optical recording apparatus of the present invention, the configuration of 'A'll that minimizes the jitter of the reproduced signal is shown in the bronch diagram of FIG. The side shown in this Figure 6 or basically the first side shown in Figure 2
The structure is the same as that of the invention described above, and a jitter detection circuit 53 is provided in place of the ^H detection circuit 33, a minimum {a detection circuit 54 is provided in place of the maximum value detection circuit 34, and the other features are as shown in FIG. It is the same as the configuration. The operation of the magneto-optical recording device of the third invention shown in FIG. 6 is as follows. The test signal is recorded in the test signal recording area of the magneto-optical recording information carrier 11 in the same manner as in the first invention. After the test signal is recorded, the laser diode 38 irradiates the test signal recording area of the magneto-optical recording information carrier 11 with a laser beam having the power to reproduce the signal. Magneto-optical recording information carrier 11
The reflected light from the optical head 3l is detected by the optical head 3l, converted into an electric signal which is a reproduced signal, and then converted into an electric signal by the width converter 32. Jitter in the reproduced signal amplified by the 1-sampler 32 is detected by a jitter detection circuit 53. The minimum value detection circuit 54 determines the position in the test signal recording area of the information carrier 11 where the minimum value of jitter detected by the jitter detection circuit 53 is detected, identifies the test signal recorded at that position, and detects the test signal recorded at that position. The level code is sent to the HQ recording level value holding circuit 35 as the most frequently recorded level. Thereafter, when recording actual signals, the code of the optimum recording level held in the recording level value holding circuit 35 is converted into an analog signal by the D/A conversion circuit 36.
It is given to the output level control terminal of LPC37, and AL
Since the signal to be recorded is given to the signal input terminal of the PC 37, the signal to be recorded is at the optimum level for magneto-optical recording. [! Recorded in in body 11. FIG. 7 is a block diagram showing an example of the configuration of the fourth invention of the magneto-optical recording device of the present invention. Here, whereas the first invention shown in FIG. 2 controls the laser power during signal recording by giving the output signal of the D/^ variable 1 negative circuit 36 to the ALPC 37, the D/A conversion circuit The output signal 36 is given to a magnetic field strength control circuit 39 that controls the strength of the magnetic field generated by the magnetic field generator l8. By adopting such a configuration, when the magneto-optical recording information carrier 1l is attached to the device, magnetic fields of various strengths are generated from the magnetic field generator l8 and are applied to the test signal recording area of the magneto-optical recording information tg world l1. It is possible to record a test signal and determine in advance the optimum magnetic field strength for recording the signal in substantially the same manner as in the case of the first invention. FIG. 8 is a block diagram showing an example of the structure of the fifth invention of the magneto-optical recording device of the present invention. Here, the second invention shown in FIG.
The output signal SE of is given to the LPC 37 to control the laser power during signal recording, whereas the inverter 41
By providing the output signal SE to the magnetic field strength control circuit 39 that controls the generated magnetic field strength of the magnetic field generator [18], by adopting such a configuration, the magnetic field can be generated when the magneto-optical recording FG carrier l1 is attached to the device. A test signal is recorded in the test signal recording area of the magneto-optical recording information fg carrier 11 while generating a magnetic field of various strengths from the device l8, and the Ria during recording of the signal is determined in substantially the same manner as in the second invention. It is possible to determine the magnetic field strength in advance. FIG. 9 is a block diagram showing a configuration example of the sixth invention of the magneto-optical recording device of the present invention. Here, the third invention shown in FIG. 6 converts the output signal of the 078 conversion circuit 36 into ^LPC3? Give it to IS issue! ! L!
While the laser power during recording is controlled, 07^
The output signal of the conversion circuit 36 is applied to a magnetic field strength control circuit 39 that controls the strength of the magnetic field generated by the magnetic field generator l8. By adopting such a structure, the test signal t! of the magneto-optical recording information carrier 11 is generated while generating magnetic fields of various intensities from the magnetic field generator l8 at the time of vt@ to the device of the magneto-optical recording information carrier 1l. It is possible to record a test signal in the eM region and obtain in advance the optimum magnetic field strength for recording the signal in substantially the same manner as in the third invention. [Effects of the Invention] As described above, according to the magneto-optical recording device of the present invention, a test signal is once written on a magneto-optical recording information carrier, and the test signal is reproduced from the maximum level of the reproduced signal or the minimum jitter of the reproduced signal. ,
Alternatively, the transmission strength of the light beam during Iδ recording or the optimal magnetic field strength applied by the magnetic field generator can be detected from the inverted signal of the tracking error signal, so the reproduced signal is always reproduced at the optimal level and magneto-optical recording is performed. This eliminates the negative influence on the reproduced signal due to vibrations caused by the flatness of the information carrier itself or incomplete attachment to the device.

[Brief explanation of the drawing]

Fig. 1 is a graph for illustrating the principle of the present invention, and shows the relationship between the magnetic field strength applied to the magneto-optical recording information carrier when recording a signal and the level when the signal is reproduced. is a block diagram showing the structure of the first invention of the magneto-optical recording device of the present invention, FIG. 3 is a schematic diagram showing the level of the test signal, and FIG. 4 is a diagram showing the test signal provided on the magneto-optical recording information carrier. Schematic diagram showing the recording area, Fig. 5. Figure 6. Figures 7 and 8
9 and 9 are the second and third embodiments of the present invention, respectively. 4th, 5th
, a block diagram showing an example of the configuration of the sixth invention, FIG.
l is a schematic diagram showing the configuration of the magneto-optical recording information F&I carrier to be processed by the apparatus of the present invention and the main parts of the apparatus of the present invention;
is a partial cross-sectional view along the circumferential direction of the magneto-optical recording information carrier,
Cl is a graph showing the power change characteristics of a laser beam for information recording on a magneto-optical recording information carrier, and FIG. Figure 12 is a graph showing the characteristics of temperature change, and Figure 13 is a graph showing the relationship between the intensity of the laser beam of the magneto-optical recording information carrier and the temperature change of the magnetic film within the laser spot. Figure 13 is a schematic diagram showing the structure of the optical system shown in U Schematic diagram showing power, Figure 15 is 4
NO) A schematic diagram showing the structure of a magneto-optical recording information carrier having a magnetic layer. FIG. 16 is a schematic diagram for explaining its operation. l1... Magneto-optical recording information carrier 18... Magnetic field generator 3l... Optical hand 33... AM detection circuit
34... Maximum value detection circuit 35... Recording level value holding circuit 36... D/Affi conversion circuit 37
...^LPC (automatic laser power control circuit) 38.
...Laser diode 39...Magnetic field strength control circuit 4l...Inverter 53...Jitter detection circuit 54...jiJ={a detection circuit Note that the same reference numerals in each figure indicate the same or equivalent parts.

Claims (6)

[Claims] (1) Magneto-optical recording information carrier Two types of signals are recorded by irradiating light beams of two types of intensities while applying a magnetic field, and the light beams are reflected by irradiating a light beam with a lower intensity than the two types of intensities. A magneto-optical recording device configured to obtain a reproduction signal of a signal recorded on the magneto-optical recording information carrier from light, comprising: a level detection circuit for detecting the level of the reproduction signal; and a level detection circuit for detecting the level of the reproduction signal. a maximum value detection circuit that detects a maximum value; a holding circuit that holds the maximum value detected by the maximum value detection circuit; and a value that is recorded on the magneto-optical recording information carrier in accordance with the value held by the holding circuit. a control circuit for converting the level of the signal, and a light beam generating means for generating a light beam under the control of the control circuit; 1. A magneto-optical recording device, characterized in that a maximum level of a reproduced signal of a recorded signal is held in the holding circuit, and this is applied to the control circuit to record the signal. (2) Magneto-optical recording information carrier Two types of signals are recorded by irradiating light beams of two types of intensities while applying a magnetic field, and the light beams are reflected by irradiating a light beam with a lower intensity than the two types of intensities. A magneto-optical recording device configured to obtain a reproduction signal of a signal recorded on the magneto-optical recording information carrier from light, comprising: a jitter detection circuit for detecting jitter in the reproduction signal; and a jitter detection circuit for detecting jitter in the reproduction signal; a maximum value detection circuit that detects the minimum value; a holding circuit that holds the minimum value detected by the minimum value detection circuit; and a value that is recorded on the magneto-optical recording information carrier in accordance with the value held by the holding circuit. a control circuit for converting the level of the signal, and a light beam generating means for generating a light beam under the control of the control circuit; 1. A magneto-optical recording device characterized in that a minimum value of jitter of a reproduced signal of a recorded signal is held in the holding circuit, and this is applied to the control circuit to record the signal. (3) Magneto-optical recording information carrier Two types of signals are recorded by irradiating light beams with two types of intensities while applying a magnetic field, and a light beam with a lower intensity than the two types of intensities is irradiated onto the signal recording area. A magneto-optical recording device configured to obtain an error signal for the signal recording area of the light beam from the reflected light, comprising: an inversion circuit for inverting the error signal; A control circuit that converts the level of a signal to be recorded on a magneto-optical recording information carrier, and a light beam generating means that generates a light beam under the control of the control circuit, and the output signal of the inversion circuit is converted to the control circuit. What is claimed is: 1. A magneto-optical recording device characterized in that the device is configured to record signals by applying signals to the magnetic field. (4) Magneto-optical recording information carrier Two types of signals are recorded by irradiating light beams of two types of intensities while applying a magnetic field, and the light beams are reflected by irradiating a light beam with a lower intensity than the two types of intensities. A magneto-optical recording device configured to obtain a reproduction signal of a signal recorded on the magneto-optical recording information carrier from light, comprising: a level detection circuit for detecting the level of the reproduction signal; and a level detection circuit for detecting the level of the reproduction signal. a maximum value detection circuit for detecting a maximum value; a holding circuit for holding the maximum value detected by the maximum value detection circuit; and a holding circuit for holding the maximum value detected by the maximum value detection circuit; and a magnetic field strength control circuit for causing the magnetic field generator to generate a magnetic field strength to be applied to the magneto-optical recording information carrier according to the magnetic field strength, the magnetic field intensity control circuit causing the magnetic field generating device to generate a magnetic field strength to be applied to the magneto-optical recording information carrier at a predetermined position of the magneto-optical recording information carrier under different magnetic field intensities. 1. A magneto-optical recording device, characterized in that a maximum level of a reproduced signal of a recorded signal is held in the holding circuit, and this is applied to the magnetic field strength control circuit to record the signal. (5) Magneto-optical recording information carrier Two types of signals are recorded by irradiating light beams of two types of intensities while applying a magnetic field, and the light beams are reflected by irradiating a light beam with a lower intensity than the two types of intensities. A magneto-optical recording device configured to obtain a reproduction signal of a signal recorded on the magneto-optical recording information carrier from light, comprising: a jitter detection circuit for detecting jitter in the reproduction signal; and a jitter detection circuit for detecting jitter in the reproduction signal; a minimum value detection circuit that detects a minimum value; a holding circuit that holds the minimum value detected by the minimum value detection circuit; and a minimum value that is held in the holding circuit when recording a signal on the magneto-optical recording information carrier. and a magnetic field strength control circuit for causing the magnetic field generator to generate a magnetic field strength to be applied to the magneto-optical recording information carrier according to the magnetic field strength, the magnetic field intensity control circuit causing the magnetic field generating device to generate a magnetic field strength to be applied to the magneto-optical recording information carrier at a predetermined position of the magneto-optical recording information carrier under different magnetic field intensities. 1. A magneto-optical recording device characterized in that a minimum value of jitter of a reproduced signal of a recorded signal is held in the holding circuit, and this is applied to the magnetic field strength control circuit to record the signal. (6) Magneto-optical recording information carrier Two types of signals are recorded by irradiating light beams with two types of intensities while applying a magnetic field, and a light beam with a lower intensity than the two types of intensities is irradiated onto the signal recording area. A magneto-optical recording device configured to obtain an error signal for the signal recording area of the light beam from the reflected light, comprising: an inversion circuit for inverting the error signal; comprising: a control circuit that converts the level of a signal to be recorded on a magneto-optical recording information carrier; and a light beam generating means that generates a light beam under the control of the control circuit; A magneto-optical recording device characterized in that it is configured to record a signal by applying it to a generating circuit.