JPS61123002A - Bias magnetic field applying device - Google Patents

Abstract

PURPOSE:To generate a homogeneous bias magnetic field with a minimum constitution without generating a large power loss due to a large-sized coil or the like by providing bias magnetic field generating coils on both dies of a recording medium. CONSTITUTION:A bias magnetic field generating part 107 consists of a yoke 107a and 107b, and the coil is fixed into the yoke by fitting or adhesion, and they are attached onto an actuator part 105. A bias magnetic field generating part 11 which faces the actuator 105 through a disc consists of a yoke 11a and a coil 12, and the yoke is a rectangular yoke provided with two side plates 11b and a center coil iron core 11c, and the rectangular ring-shaped coil is fitted to this yoke and is stuck to it, and this bias magnetic field generating part 11 is arranged in the radial direction of the disc. Since two bias magnetic field generating parts take equally charge of a magnetic field of the same intensity, problems of countermeasure against heating, increase of the size of a power source, etc. are resolved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for applying a bias magnetic field to a disk-shaped recording medium in a perpendicular magnetization type magneto-optical recording system.

'G Nail Conventionally, there are two types of bias magnetic field application methods used in perpendicular magnetization type magneto-optical recording devices: a bias magnetic field moving type and a fixed type. Since the head for applying a bias magnetic field must be moved in the radial direction of the disk depending on the position, the moving mechanism is complicated, and an absent bias magnetic field applying device is known, which leads to an increase in the size of the magnetic recording device (Japanese Patent Application Laid-Open No. 5
7-178505).

In the system shown in FIG. 8, a large coil 4 is installed around the outer periphery of the disk 2, and a bias magnetic field is applied over the entire area of the disk 2.

This has the advantage that it does not require a complicated movement mechanism compared to a method using a moving head, but the coil installed around the outer periphery of the disk 2 is large and has to be used to obtain the magnetic field strength necessary for recording or erasing information on the disk. requires a large amount of power,
This causes many problems, such as heat generation in the coil, an increase in the size of the power supply, and difficulty in obtaining a uniform magnetic field strength.

The system shown in FIG. 8 has been developed to solve these problems, in which permanent magnets 5 are arranged in parallel in the radial direction of the disk 2 as means for generating a noisy magnetic field, and a motor 6 is used to generate a magnetic field. By rotating the permanent magnet 5 and adjusting the magnetic field strength and direction as desired, this method attempts to eliminate the power loss caused by the head moving mechanism and large coil, which are the problems of the conventional technology. However, there are still unresolved problems such as the need for a permanent magnet and the need for a mechanical part to rotate the permanent magnet, and there is still room for improvement as a practical bias magnetic field application method. have

Eyes of the Invention - In view of the above-mentioned problems with the bias magnetic field application method of the conventional perpendicular magnetization type magneto-optical recording device, the present invention provides a method for applying a large coil to the bias magnetic field hend etc. without requiring a special moving mechanism. It is an object of the present invention to provide a practical bias magnetic field applying device that generates a homogeneous bias magnetic field with a minimum configuration without causing large power loss due to such factors.

The present invention provides a bias magnetic field generating coil provided around a perpendicular magnetization type magneto-optical recording or erasing pickup lens or at a position opposite to the pickup lens to sandwich the disk, in which the bias magnetic field generating coil is located near the disk. It has a bias magnetic field applying device having a rectangular annular coil in the radial direction.

1' - Example Hereinafter, the present invention will be specifically explained with reference to Examples.

FIG. 1 is a schematic perspective view showing the arrangement of bias magnetic field generating coils in an embodiment of the present invention. 106 is a disk-shaped magnetic recording material (
(hereinafter simply referred to as a disk), 105 is a focusing;
The actuator section 107 and 11 of the pickup equipped with a tracking mechanism are bias magnetic field generating sections.

+01 is a semiconductor laser light generator, 102 is a collimator,
Reference numeral 103 indicates a shaped prism, and 104 indicates a total reflection prism. The laser beam emitted from the semiconductor laser light generator 101 is received by a collimator lens 102, and the beam is shaped by the shaped prism 103, followed by a half prism.
The light passes through the actuator 108 and is reflected into the actuator 105 by the total reflection prism 104, and is focused into a sudt light by the objective lens in the actuator 105 to irradiate the disk 108 for recording, erasing, or reproduction.

The light reflected by disk 10B is totally reflected prism +0
4, the light from the other surface of the half prism 108 is reflected, and the light is focused by a lens +10 and converted into a signal by an APD (avalanche, photodiode) 111.

On the other hand, part of the light that passed through the half prism lO8 is
Total reflection on the other surface of prism 109, critical angle prism
112 and enters a four-part detector 113, where it becomes a tracking signal and a focusing signal.

In the series of actions described above, the bias magnetic field generating section 10
Numerals 7 and 11 generate a bias magnetic field when recording or erasing on a disk, and a bias magnetic field generating unit 107
As shown in FIG. 2, the yoke 107a and the coil 107b
It consists of a coil inside the yoke! It is attached to the upper part of the actuator section 105 by fixing it by inserting it or gluing it.

As is clear from the figure, the yoke 107a has a through hole 10 in the center. A groove having a U-shape in radial cross section is provided, and a donut-shaped annular coil 107b is fitted into the groove.

In addition, a bias magnetic field generating section 11 is provided at a position facing the actuator 105 so as to sandwich the disk therebetween.
As shown in Fig. 3, the yoke consists of a yoke Ila and a coil 2, which is a rectangular yoke having two side plates 11b and a coil core +1c in the center, into which a rectangular annular coil is fitted and fixed. It is what was done. As shown in FIG. 1, this bias magnetic field generating section 11 is arranged along the radial direction of the disk by a supporting device which will be described later.

FIG. 4 shows a support device for a bias magnetic field generating coil in this embodiment, in which the coil is attached to a disk clamp support plate of a disk exchange type.

38 is a disk clamp support plate, which protrudes laterally 4
A wooden guide bin 38 is provided, and its vertical movement is controlled by the cam portion 35 of the disc jacket guide member 32 and the guide groove 41 provided in the side plate of the device, which is shown surrounded by diagonal lines.

15 indicates the center of the disk (not shown); 14
indicates a disc clamp.

Reference numeral 12 indicates a bias magnetic field generating coil of a bias magnetic field generating section fixed to the disk clamp support.

In such a configuration, when the well-known disc jacket 31 containing a disc is inserted into the guide member 32, the guide member 32 first inserts the guide bin 3 protruding from the side surface of the guide member 32.
3 and along the horizontal portion of the guide groove 34, which is indicated by an inverted diagonal line on the side plate of the device. At the same time, the disk clamp support plate 38 begins to gradually descend due to the cam portion 35 and guide groove 41 provided in the guide member.

When the bottle 33 of the guide member 32 reaches the end of the guide groove 34,
The guide pin 39 of the disk clamp support plate 38 also has a spring 4.
2 and reaches the lowest part of the cam portion of the guide member 32, and the disc clamp 14 is set in a predetermined position relative to the disc within the disc jacket 31. After that, the disk clamp support plate 38 and the guide member 32 are further attached to the spring 4.
3, it descends vertically along guide grooves 41 and 34,
A positioning means (not shown) determines the distance between the pickup and the cutter, and the clamping action is completed, completing preparations for recording or erasing the disc.

FIG. 5 is a schematic cross-sectional view showing the positional relationship between the actuator, the bias magnetic field generating coil, and the disk in a state where recording or erasing preparations are completed, and 12 is the bias magnetic field generating coil attached to the disk clamp support plate. ,
105 is an actuator mounted on a pickup moving carriage (not shown); 10? 106 is a disk, 14 is a disk clamp, and 31 is a disk jacket.

6 and 7 show cross sections of main parts of the actuator and the bias magnetic field generating section provided above in the embodiment of the present invention, and FIG. 6 shows the position facing the actuator with the disk 108 in between.

The one in which bias magnetic field generating coils 114b and 107b are provided both around the objective lens 105a of the actuator, and FIG. 7 shows the one in which the bias magnetic field generating coil 114b is provided only in a position facing the actuator, and the arrows indicate the magnetic field distribution. This shows that.

According to the present invention, compared to the bias magnetic field applying device of a conventional perpendicular magnetization magneto-optical recording device, a large coil is not required, power consumption is low, and a bias magnetic field is uniformly distributed only in the area where the bias magnetic field is required. can be applied, eliminating problems such as heat generation and increasing the size of the power supply.The number of components is small, and the space is not taken up.
This has the effect of making it possible to obtain a smear field applying device.

Furthermore, by attaching a rectangular annular bias magnetic field generating coil to the disk clamp support plate, even in disk exchange type devices, there is no need for a special mechanism for moving the bias magnetic field generating coil, making it uniform and efficient with low power consumption. Thus, a bias magnetic field applying device can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a schematic perspective view showing the arrangement of a bias magnetic field generating coil according to an embodiment of the present invention, Fig. 2 is an exploded perspective view of a bias magnetic field generating section on an actuator, and Fig. 3 is a coil provided opposite to the actuator. FIG. 4 is an exploded side view of the bias magnetic field generation section, FIG. 4 is a support device for the bias magnetic field generation coil facing the actuator, FIG. 5 is a schematic sectional view showing the positional relationship of the actuator, the bias magnetic field generation coil, and the disk; 8 and 7 are sectional views of the main parts of the bias magnetic field generating section in this embodiment, and FIGS. 8 and 9 are explanatory views of the main parts showing the prior art, respectively. 10B・・・・・・・・・・・・Disk-shaped recording medium 105・・・・・・・・・・・・Actuator 107.11・・・・・・・・・/ Heiame magnetic field generation part +05a・・・・・・・・・Objective lens +2
, l07a... Bias magnetic field generation coil 3
8・・・・・・・・・・・・・・・Disc clamp support plate 11a, +07a-・=Yoke Figure 1 section ① Procedure amendment (voluntary) April 15, 1985 Patented in 1988 Application No. 245488 2, Name of the invention Bias magnetic field application device 3, Relationship to the case of the person making the amendment Patent applicant address 2-43-2-4 Hatagaya, Shibuya-ku, Tokyo, Agent 6, Specification subject to amendment Full text 7, Description of amendments Document 1, Title of the invention Bias magnetic field applying device 2, Claims (1) Bias magnetic field generating coils are provided on both sides of the recording medium in a perpendicular magnetization type magneto-optical recording device. A bias magnetic field applying device characterized by being provided. 3. Detailed Description of the Invention Technical Field of the Invention The present invention relates to an apparatus for applying a bias magnetic field to a disk-shaped recording medium in a perpendicular magnetization type magneto-optical recording system. BACKGROUND ART Conventionally, as a bias magnetic field applying method used in a perpendicular magnetization type magneto-optical recording device, a bias magnetic field applying device as shown in FIGS.
(See Publication No. 78505). In the system shown in FIG. 11, a large coil 4 is installed around the outer periphery of the disk 2, and a bias magnetic field is applied over the entire area of the disk 2. In addition, in FIG. 12, permanent magnets 5 are arranged in parallel to each other in the radial direction of the disk 2 as means for generating a bias magnetic field, and the permanent magnets 5 are rotated by a motor 6 to adjust the desired magnetic field strength and direction. are doing. Both methods require a large amount of power to generate a magnetic field over the entire area of the disk, and require cooling means to handle the heat generated by the coil. Have room. Purpose of the Invention In view of the above-mentioned problems with the bias magnetic field application method of the conventional perpendicular magnetization type magneto-optical recording device, the present invention provides a bias magnetic field head, etc., without causing large power loss due to large coils, etc. The present invention aims to provide a practical bias magnetic field applying device that generates a homogeneous bias magnetic field with a minimum configuration. Summary of the Invention The present invention improves efficiency in perpendicular magnetization type magneto-optical recording by providing bias magnetic field generating coils at both a pickup and a position facing the actuator of the pickup, with a magnetic disk sandwiched therebetween. It is something. EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples. FIG. 1 is a schematic perspective view showing the arrangement of bias magnetic field generating coils in an embodiment of the present invention. 10B is a disk-shaped magnetic recording material (
(hereinafter simply referred to as a disk), 105 is a focusing;
The actuator section 107 and 11 of the pickup equipped with a tracking mechanism are bias magnetic field generating sections. 101 is a semiconductor laser light generator, 102 is a collimator, 103 is a shaped prism, and 104 is a total reflection prism. After forming, it passes through a half prism 108 and is reflected into an actuator 105 by a total reflection prism 104.
A spot light is focused by an objective lens inside the disc 10B and irradiated onto the disc 10B for recording, erasing, or reproducing. The light reflected by the disk 106 passes through the total reflection prism 10
4, a portion of the light is reflected by the other surface of the half prism 108, and the light is focused ξ by a lens 110 and converted into a signal by an APD (avalanche photodiode) 111. On the other hand, a part of the light that has passed through the half prism 108 is totally reflected on the other surface of the prism 109 and passes through the critical angle prism 11.
2 and enters the four-part detector 113, where it becomes a tracking signal and a focusing signal. In the series of actions described above, the bias magnetic field generating section 10
Numerals 7 and 11 generate a bias magnetic field when recording or erasing on a disk, and bias magnetic field generating units 10?
As shown in FIG. 2, the yoke 107a and the coil 107b
The coil is fitted into the yoke or fixed by adhesive, and is attached to the second part of the actuator section 105. As is clear from FIG. 1, the yoke l07a has a through hole 107d in the center, and is provided with a concave groove having a U-shaped radial cross section, and a donut-shaped annular coil 107b is installed in the concave groove. is now inserted. In addition, a bias magnetic field generating section 11 is provided at a position facing the actuator 105 so as to sandwich the disk therebetween.
As shown in FIG. 3, the yoke consists of a yoke lla and a coil 12, and the yoke is a rectangular yoke having two side plates 11b and a coil core 11c at the center, into which a rectangular annular coil is fitted and fixed. It is something that and,
As shown in FIG. 1, this bias magnetic field generating section 11 is arranged along the radial direction of the disk by a supporting device which will be described later. FIG. 4 shows a support device for a bias magnetic field generating coil in this embodiment, in which the coil is attached to a disk clamp support plate of a disk exchange type. Reference numeral 38 denotes a disc clamp support plate, which is provided with four guide pins 38 projecting laterally, and is connected by a cam part 35 of the disc jacket guide member 32 and a guide groove 41 provided in the side plate of the device shown surrounded by diagonal lines. The downward movement is controlled by -. 15 indicates the center of the disk (not shown); 14
indicates a disc clamp. Reference numeral 12 indicates a bias magnetic field generating coil of a bias magnetic field generating section fixed to the disk clamp support. In such a configuration, when a well-known disk jacket (31) containing a built-in disk is inserted into the guide member 32, the guide member 32 first inserts the guide pin 3 protruding from the side surface of the guide member 32.
3 and along the horizontal portion of the guide groove 34, which is indicated by an inverted diagonal line on the side plate of the device. At the same time, the disk clamp support plate 38 begins to gradually descend due to the cam portion 35 and guide groove 41 provided in the guide member. When the pin 33 of the guide member 32 reaches the end of the guide groove 34,
The guide pin 38 of the disk clamp support plate 38 also has a spring 4.
2 and reaches the lowest part of the cam portion of the guide member 32, and the disc clamp 14 is set in a predetermined position relative to the disc within the disc jacket 31. After that, the disk clamp support plate 38 and the guide member 32 are attached to the spring 4.
3, it directly descends F along guide grooves 41 and 34,
A positioning means (not shown) determines the distance between the pickup and the actuator, completes the clamping action, and completes preparations for recording or erasing the disc. FIG. 5 is a schematic cross-sectional view showing the positional relationship between the actuator, the bias magnetic field generating coil, and the disk in a state where recording or erasing preparations are completed, and 12 is a bias magnetic field generating coil attached to the disk clamp support plate. 105 is an actuator placed on a carriage for moving the pickup (not shown); +07 is a bias magnetic field generator provided in a part of the actuator 1; 106 is a disk; 14 is a disk clamp; 31 is a disk jacket. 6 and 7 are cross-sectional views of main parts of the bias magnetic field generating section provided at the actuator and the actuator in the embodiment of the present invention, and FIG. 6 shows the position facing the actuator with the disk 1013 in between. , a bias magnetic field generating coil 1 is placed both around the objective lens 105a of the actuator.
14b and 107b, the one in FIG. 7 has the bias magnetic field generating coil 1 only at the position facing the actuator.
14b, and the arrows indicate the magnetic field distribution. Note that the bias magnetic field generating section 11 is replaced by the bias magnetic field generating section 1.
The bias magnetic field generating section 107 has the same shape as 07, so that the magnetic field can be applied to the same location as the bias magnetic field generating section 107.
may be coupled to means for moving the actuator 105 in the disk radial direction. Effects of the Invention According to the present invention, compared to the bias magnetic field applying device of a conventional perpendicular magnetization type magneto-optical recording device, since coils for applying a bias magnetic field are provided on both sides of the disk, the same strength can be achieved. Since the generation of the magnetic field can be shared equally between two devices, problems such as heat generation countermeasures and increasing the size of the power supply have been solved. This has the effect of making it possible to obtain a bias magnetic field applying device. 4. Brief description of the drawings Fig. 1 is a schematic perspective view showing the arrangement of the bias magnetic field generating coil according to the embodiment of the present invention, Fig. 2 is an exploded perspective view of the bias magnetic field generating part of the actuator 1-, Fig. 3 4 is an exploded perspective view of the bias magnetic field generating section provided facing the actuator, FIG. 4 is a support device for the bias magnetic field generating coil facing the actuator, and FIG. 5 is the positional relationship between the actuator, the bias magnetic field generating coil, and the disk. FIGS. 6 and 7 are sectional views of the main parts of the bias magnetic field generating section in this embodiment, and FIGS. 8 and 8 are explanatory views of the main parts of the prior art, respectively. 10B......Disk-shaped recording medium 105...Actuator 107.11...Bias Magnetic field generating section 105a... Objective lens 12
, l07a... Bias magnetic field generation coil 3
8・・・・・・・・・・・・Disc clamp support plate 11a, 1G7a=-Yoke Patent applicant Olympus Optical Industry Co., Ltd. Procedural amendment (voluntary) 1. Display of the case 1982 Patent Application No. 245488 2, Name of the invention Bias magnetic W applying device 3, Person making the amendment Relationship to the case Patent applicant address 2-43-2-4 Hatagaya, Shibuya-ku, Tokyo, Japan 6. In the description subject to amendment, column ``Detailed Description of the Invention'', drawing 7, content of amendment, page 7, line 2, page 7, line 18, the description ``disc jacket toyo'' has been changed to (2) In the drawings, Figure 6 is corrected as shown in the attached sheet. 8. List of attached documents

Claims (3)

[Claims] (1) In a perpendicular magnetization type magneto-optical recording device, in a bias magnetic field applying device, a bias magnetic field generating coil is provided at a position facing an actuator of a pickup and sandwiching a disk-shaped recording medium; A bias magnetic field applying device characterized in that the bias magnetic field generating coil is an annular coil fitted in a rectangular yoke along the radial direction of a disk-shaped recording medium. (2) The bias magnetic field applying device according to claim 1, wherein the actuator is provided with a bias magnetic field generating coil around the objective lens. (3) The bias magnetic field generating coil provided opposite to the actuator is attached to a disk clamp support plate of a disk exchange type device, as set forth in claim 1 or 2. Bias magnetic field application device.