JPH01146178A - cartridge - Google Patents

Abstract

PURPOSE:To apply a necessary bias magnetic field with use of a small magnet and to miniaturize the whole of the title device by providing opening parts so that a bias magnetic field generating means can be placed close to a photo- electro-magnetic recording medium housed in the internal part of the device. CONSTITUTION:For a cartridge 23, an opening 21 for a first bias magnet 15 and an opening 22 for a second bias magnet 16 are respectively provided so that the first bias magnet 15 and the second bias magnet 16 can be placed close to a photo-electro-magnetic disk 12. When the cartridge 23 is loaded, the first and the second bias magnets 15 and 16, which are under an sheltered state, are moved to be inserted into the openings 21 and 22 for the bias magnets and stopped at a prescribed distance from the disk 12. Thus, a strong bias magnetic field can be generated even with the small bias magnet 15 and 16, and the device can be miniaturized.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a Chierry point writing type magneto-optical recording medium (magneto-optical disk, etc.) that uses the magnetic Kerr effect for reproduction.
- A cartridge for a magneto-optical recording medium housed inside the cartridge.

[Background of the invention]

Magneto-optical disks are known as erasable optical disks. Magneto-optical disks have advantages over magnetic recording media using conventional magnetic heads, such as high-density recording and non-contact recording and playback, but on the other hand, the recorded area must be erased before recording. It had the disadvantage that it cannot be magnetized in one direction (it must be magnetized in one direction). In order to compensate for this drawback, methods have been proposed in which a recording/reproducing head and an erasing head are provided separately, or a method in which recording is performed while irradiating a continuous radar beam while simultaneously modulating the applied magnetic field. .

However, these methods have drawbacks such as the large size of the device, high cost, and inability to perform high-speed modulation.

Recently, magneto-optical recording devices have been developed that enable overwriting similar to magnetic recording media by simply adding a magnetic field generating means with a simple structure to the conventional device configuration.
method) has been proposed.

That is, the above method consists of a first magnetic layer having a low Curie point (TL) and a high coercive force (HH), and a relatively high Curie point (TH) and low coercive force (HL) compared to this magnetic layer.
) using a magneto-optical recording medium having a two-layer perpendicularly magnetized film on a substrate.
This is done by recording the values.

(a) With respect to the medium, at a location different from the recording head,
Applying a magnetic field B having a magnitude sufficient to magnetize the second magnetic layer having a coercive force HL in one direction and not reversing the direction of magnetization of the first magnetic layer having a coercive force H8, (b) Next, In the recording head section, a bias magnetic field having a magnetic field direction opposite to the direction of the magnetic field B is applied, and at the same time, the magnetization direction of the first magnetic layer is uniformly changed at a temperature near the low Curie point (TL). The direction of the magnetization of the second magnetic layer is changed by irradiating the medium with a laser power sufficient to raise the temperature of the medium to a temperature at which the medium can be aligned in a stable direction with respect to the direction of magnetization of the second magnetic layer. Either the first type of preliminary recording, in which the direction of magnetization of the first magnetic layer is aligned in a stable direction with respect to the second magnetic layer, while the magnetic field remains The direction of magnetization of the second magnetic layer is reversed by irradiating the medium with a laser or power that is sufficient to raise the temperature of the medium to a temperature at which the direction of magnetization of the second magnetic layer can be uniformly reversed. At the same time, a second type of preliminary recording is performed in which the first magnetic layer is also magnetized in a stable direction with respect to the second magnetic layer, according to the signal. By passing the magnetic field B through the pits formed by the magnetic field B, the direction of magnetization of the pits formed by the first preliminary recording is not changed (first type recording), and the second type preliminary recording is performed. Regarding the pits formed by recording, only the direction of magnetization of the second magnetic layer is reversed to the same direction as the magnetic field B (second type recording), and this is performed by binary recording as described above. .

The above recording method will be explained below with reference to the drawings.

FIG. 2(a) (monovalent) is a schematic cross-sectional view showing a configuration example of a magneto-optical recording medium used in each of the above-described recording methods.

The magneto-optical recording medium shown in FIG. 2(a) has a first magnetic layer 2 and a second magnetic layer 3 laminated on a transparent substrate 1 provided with a pre-group. The first magnetic layer 2 has a low Keely point (TL) and a high coercive force (TH), and the second magnetic layer 3 has a high Keely point (TH) and a low coercive force (HL).
). Here, "high" and "low" represent a relative relationship when comparing the inner magnetic layers (coercive force is compared at room temperature).

However, normally the TL of the first magnetic layer 2 is 70 to 180°C,
HH is 3 to 10 KO・, TH of the second magnetic layer 3 is 150
~400°C, and HL is preferably within the range of about 0.5 to 2KO6.

In the above-described magneto-optical recording method, the first magnetic layer 2 is mainly involved in reproduction. That is, the magneto-optic effect exhibited by the first magnetic layer 2 is mainly used for reproduction. - On the other hand, the second magnetic layer 3 plays an important role in recording.

In FIG. 2(b), 4 and 5 are protective films for improving the durability of the inner magnetic layers 2 and 3 or for improving the magneto-optical effect.

Reference numeral 6 denotes an adhesive layer for bonding the bonding substrates 7 together. If layers 2 to 6 are laminated on the laminating substrate 7 and these are adhered, recording and reproduction can be performed on the front and back sides.

The recording process will be described below with reference to FIGS. 3 to 5. Before recording, the stable magnetization directions of the inner magnetic layers 2 and 3 may be parallel or antiparallel. In FIG. 3, an example will be explained in which the stable directions of magnetization are parallel.

Reference numeral 35 in FIG. 4 is a magneto-optical disk having the configuration described above. For example, suppose that the magnetization state of a certain part of this magnetic layer is initially as shown in FIG. 3(a). The magneto-optical disk 35 is rotated by a spindle motor and passes through the magnetic field generating section 34 .

At this time, the magnitude of the magnetic field of the magnetic field generating section 34 is adjusted to the inner magnetic layer 2.
When the coercive force is set to a value between . The magnetization of the first magnetic layer 2 remains as it was at the beginning. Next, when the magneto-optical disk 35 rotates and passes the recording/reproducing head 31, two types (the first type and the second type) are generated according to the signal from the recording signal generator 32.
A laser beam with a laser power value of is irradiated onto the disk surface. The laser power of the first type is 7, which is enough to raise the temperature of the disk to around the Q, IJ- point of the first magnetic layer 2.
The second type of laser power is a power capable of heating the disk to near the Chierly point of the second magnetic layer 3. That is, in FIG. 5, which schematically shows the relationship between the coercive force and temperature of both magnetic layers 2.3, the first type laser power is near TL and the second type is L/-f-/#qua-T. It is possible to raise the temperature of the disk to around 500 yen.

The temperature of the first magnetic layer 2 increases to near the Chierly point due to the first type of laser power, but the second magnetic layer 3 has a coercive force that allows bits to stably exist at this temperature, so during recording. By setting the bias magnetic field appropriately, recording bits as shown in FIG. 3(c) are formed (first type of preliminary recording).

Setting the bias magnetic field appropriately means the following. That is, in the first type of preliminary recording, the magnetization of the first magnetic layer 2 receives a force (exchange force) that aligns it in a stable direction (here, in the same direction) as the direction of the magnetization of the second magnetic layer 3. , a bias magnetic field is not originally required. However, the bias magnetic field is set in a direction that assists the magnetization reversal of the second @-type layer 3 in preliminary recording using the second type of laser power, which will be described later.

Further, it is preferable that the bias magnetic field is set to have the same magnitude and direction in preliminary recording with either the first type or the second type of laser power.

From this point of view, it is preferable to set the bias magnetic field to the minimum magnitude necessary for preliminary recording of the second type of laser power based on the principle shown in the figure below.

When the temperature of the second magnetic layer 3 is raised to almost one point by the second type of laser power (second type of preliminary recording), the magnetization of the second magnetic layer 3 is increased by the above bias magnetic field. The direction is reversed. Subsequently, the magnetization of the first magnetic layer 2 is also aligned in a stable direction (here, in the same direction) with respect to the second magnetic layer 3. That is, recording bits as shown in FIG. 3(d) are formed.

In this way, the bias magnetic field and the first
Depending on the laser power of the seed and the second type, recording bits are recorded at each location on the magneto-optical disk in the state shown in FIG. 3(c) or (d).

Next, rotate the magneto-optical disk 35 and record the recording pitch) (c
When the magnetic field generating section 34 is set between the magnetic layers 2 and 3 as described above, when the recording pitch (1) and (d) passes through the magnetic field generating section 34 again, the recording pitch (c) remains unchanged. The state is (,). On the other hand, the recording bit (d) is the second
The magnetic layer 3 undergoes magnetization reversal and enters the state (4).

In order for the state of the recorded bit (r) to exist stably, the magnitude of saturation magnetization t-Mm and the film thickness of the second magnetic layer 3 are required.

Assuming that the domain wall energy between the magnetic layers 2 and 3 is σW, the following relationship may be satisfied.

σW −<HL<HH Msh0w72M5h indicates the strength of the exchange force acting on the second magnetic layer. This means that an attempt is made to orient the magnetization direction of the second magnetic layer 3 in a stable direction (in this case, the same direction) as the magnetization direction of the first magnetic layer 2 using a magnetic field with a magnitude of 0w72M5h. However, in order to prevent the magnetization of the second magnetic layer 3 from reversing against this magnetic field, the coercive force of the second magnetic layer 3 should be 9〉σw/2Mah as HL.

The recording bit states (・) and (f) are the radar data at the time of recording.
Since it is controlled by 74 words and does not depend on the state before recording, overwriting is possible. Then, the recorded bits (.) and (f) fl are irradiated with a laser beam for reproduction, and the reproduction source is processed by the recording signal regenerator 33, thereby reproducing the data.

In the explanation of FIG. 3, an example is shown in which the first magnetic layer 2 and the second magnetic layer 3 are stable when their magnetization directions are the same, but the same applies to magnetic layers that are stable when their magnetization directions are antiparallel. Conceivable. Figure 6 shows the magnetization state during the recording process in this example.
I will show it in correspondence with the figure. (Furthermore, Fig. 3 and Fig. 6 are diagrams showing examples of different magnetic layers.) Magneto-optical recording media (disks) used in the above recording methods are , is expected to be used with a cartridge containing the media therein.

However, when using a magneto-optical recording medium housed inside a cartridge, the above-mentioned recording method requires that two bias magnetic fields having different magnetic forces be subtly applied to the recording medium. Applying the magnetic field from above has a problem in that efficiency is poor and the device becomes larger or more expensive.

〔the purpose〕

The present invention has been made in view of the above-mentioned problems, and its purpose is to provide a cartridge for a magneto-optical recording medium that can accurately and delicately apply a bias magnetic field to the magneto-optical recording medium (disk). It's about doing.

[Means for solving problems]

According to the invention, the above object is achieved by a cartridge characterized in that it has an opening through which a bias magnetic field generating means can approach a magneto-optical recording medium housed therein.

〔Example〕

Hereinafter, embodiments of the present invention will be described specifically and in detail based on the drawings.

FIG. 1 shows the first cartridge of the magneto-optical recording medium cartridge of the present invention.
It is a side sectional view showing an example of this.

In FIG. 1, 11 indicates an optical head. Reference numeral 12 denotes a magneto-optical disk having the above-mentioned two-layer perpendicular magnetization film.

A spindle motor 13 rotates the magneto-optical disk 12. 14 is a clamper that fixes the magneto-optical disk 12 to the spindle motor shaft. Reference numeral 15 denotes a first disk located opposite to the optical head 11 across the magneto-optical disk 12.
It is a bias magnet. A second bias magnet 16 is located at a different position from the first bias magnet 15. These two magnets may be either electromagnets or permanent magnets, but rare earth permanent magnets are used in this embodiment because there is no need to switch the direction of the magnetic field and the device is simple.

The magnetic field strength of the first bias magnet 15 is set to 1000e on the disk 12, and the magnetic field strength of the second bias magnet 16 is set to 2.5e on the disk 12.
It is set to be KO@.

The operation of this embodiment will be explained below.

spindle motor 13 without first turning on the lede light.
The disk 12 is rotated at 90 rpm, and the second bias magnet 16 directs the magnetization direction of the second magnetic layer (3 in FIG. 3) of the disk 12 in a fixed direction.

Next, the radar light is turned on in the optical heald 11 and the first bias magnet 15, and preliminary recording is performed using two types of beams i4W (4 mW and 8 mW in this embodiment).

(FIGS. 3(c) and (d)) After that, when the light passes through the second bias magnet 16 again, the binary values of tel and (f) in FIG. 3 are recorded.

When reproducing, the laser beam is irradiated with a drop of 1 mW to the radar arm, and the recorded data is read out using the magneto-optic effect.

If you want to rewrite different data after that, it is possible to overwrite the data by recording it in the first bias magnet 15 and optical head 11 using a two-step radar controller and then passing it through the second bias magnet 16. becomes.

The cartridge 23 of the present invention shown in FIG. 1 has a shape as shown in the same figure. That is, the cartridge 23 of this embodiment has openings 21 for the first bias magnet and openings 21 for the second bias magnet, respectively, so that the first bias magnet 15 and the second bias magnet 16 can be brought close to the magneto-optical disk 12. An opening 22 is provided. Since the second bias magnet 16 is generally required to have a stronger magnetic force than the first noisy magnet 15, it is more efficient to place the second bias magnet 16 closer to the disk 12, and it is possible to miniaturize the magnet and the device. It becomes possible. 20 is an aperture for an optical head.

When the cartridge 23 is loaded, the first and second bias magnets 15.16 that have been retracted move to be inserted into the bias magnet openings 21.22, and stop at a predetermined distance from the disk 12. . By doing this, even a small bias magnet can generate a strong bias magnetic field.

FIG. 9 is a perspective view of the cartridge 23 shown in FIG. 1. As shown in the figure, the first bias magnet opening 21, the second
An optical head opening 20 (not shown) is provided on the back side of the bias magnet opening 22 and the first bias magnet opening 21 (on the opposite side of the IC), and a shutter 24 is provided to avoid the influence of dirt and dust. It is equipped with a lid and is supposed to be closed when not in use.

FIG. 7 is a side sectional view of a car I/J edge showing a second embodiment of an overwriting device based on the same principle. In the same figure, instead of the first bias magnet 15 in FIG. In this example, a bias magnetic field is used, and the second bias magnet 16 is also placed on the same side of the disk 12 as the optical hepat 11, which allows the number of parts to be reduced and the device to be made more compact.

FIG. 8 is a plan view of a cartridge showing a third embodiment of an overwriting device based on the same principle. In the figure, a second noisy magnet 19 is placed on the optical head 11. The first bias magnet shares the leakage magnetic field of the drive magnet of the actuator 17, as in the example shown in FIG. This embodiment allows for further miniaturization of the apparatus shown in FIG.

A perspective view of the cartridge corresponding to FIG. 7 is shown in FIG. 10. The illustrated opening 25 serves both as an opening for the optical head and as an opening for the first bias magnet.

A perspective view of the cartridge corresponding to FIG. 8 is as shown in FIG. 11. The illustrated opening 26 is wide enough to allow entry of the first bias magnet and second bias magnet 19 on the optical radar 11 in FIG. 8, and the optical radar 11. It has become.

〔Effect of the invention〕

As explained above in detail and concretely, the low Curie point (
a first magnetic layer having a high coercive force (HH);
a relatively high Curie point (TH) with respect to the first magnetic layer;
and a second magnetic layer having a low coercive force (HL).
By applying a bias magnetic field and a second bias magnetic field and irradiating a laser beam with two levels of energy intensity based on the desired recording modulation, overwriting can be easily performed. An energy-saving magneto-optical recording device with a small number of parts can be provided. It is conceivable to house the magneto-optical recording medium used in this case in a car (IJ) for protection.
At this time, the cartridge of the present invention can apply the necessary bias magnetic field using a small magnet near the magneto-optical recording medium without applying a strong bias magnetic field from outside the cartridge, so the entire device can be miniaturized. It becomes possible.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view showing a first embodiment of the cartridge of the present invention, FIGS. 2(a) and (b) are schematic sectional views showing an example of the configuration of a magneto-optical recording medium, and FIG. 3(a) 〜(f) and FIG. 6(a') 〜(f5
The first section explains each recording method. A diagram showing the magnetization direction of the bit of the second magnetic island, □ Figure 4 is a conceptual diagram of the recording/reproducing device, and Figure 5 is a diagram showing the direction of magnetization of the bit of the second magnetic island.
A schematic diagram showing the relationship between the temperature and coercive force of the second magnetic layer; FIG. 7 is a side sectional view showing the second embodiment of the cartridge; FIG. 8 is a plan view showing the third embodiment of the cartridge; 9 is a perspective view of the cartridge shown in FIG. 1, FIG. 10 is a perspective view of the cartridge shown in FIG. 7, and FIG. 11 is a perspective view of the cartridge shown in FIG.
FIG. 2 is a perspective view of the cartridge shown in the figure. 11: optical head, 12: magneto-optical disk, 15: first bias magnet, 16: second bias magnet, 20: opening for optical head, 21: opening for first bias magnet, 22:
Second bias magnet opening, 23: Cartridge. Agent: Johei Yamashita, Figure 1, Figure 2 (b), Figure 3, Figure 4, Figure 5, Figure 6 (procedural amendment form) February 26, 1986 Director General of the Patent Office Kunio Ogawa 1. Indication of the case Japanese Patent Application No. 62-303196 2. Name of the invention cartridge 3. Person making the amendment Relationship to the case Patent applicant name (100) Canon Co., Ltd. 4. Agent address Tokyo Mori Building, 40 Toranomon, 5-13-1, Toranomon, Minato-ku February 23, 1988 6, Brief description of the drawings in the specification subject to amendment and Drawing 7, Contents of amendment (1) Page 18 of the specification The 4th line "Figure 6 (a') ~ (
f') is corrected to "Fig. 6(a) to O) is". Correct to. 6th C) Fu (d) (e) (f) Tsu firefly 1 vinyl 41

Claims (2)

[Claims] (1) A cartridge characterized by having an opening through which a bias magnetic field generating means can approach a magneto-optical recording medium housed inside. (2) The bias magnetic field generating means is two types of bias magnetic field generating means having mutually different magnetic forces and with the directions of the respective magnetic fields opposite to each other. The cartridge described in (1).