JPH01199301A - magneto-optical storage device - Google Patents

Abstract

PURPOSE:To obtain an optical magnetic recorder to be simultaneously equipped with a high density, a large capacity and the overwrite function of a magnetic disk by forming the magnetic head of a magnetic core to impress a magnetic field to a recording carrier and a slider to float the magnetic head from different materials. CONSTITUTION:A floatation type magnetic head is composed of a head core, in which an effective magnetic field impression area is wide (0.2mmX0.5mm), and the slider in which a floating quantity is large (equal to >=1mum) even at a low linear velocity. Further, the magnetic head is made into a construction in which a magnetic substance core in a U shape is buried in the nonmagnetic slider. Namely, an optical head and the magnetic head are made opposite in sandwiching the recording carrier, simultaneously, the floatation type magnetic head is used as the magnetic head, light is projected from the substrate side of the recording carrier by means of the optical head, and the magnetic field to be polarity-inverted or intensity-modulated are impressed according to record information by means of a magnetic head from an optical magnetic recording film side. Thus, the signal of the degree of several MHz can be recorded, and the optical magnetic storage device to be equipped with both the high density and large capacity can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magneto-optical recording device, and more particularly to a magneto-optical disk device that can be overridden using a magnetic field modulation recording method.

[Prior Art] Conventionally, overridable magneto-optical disk devices are disclosed in Japanese Patent Application Laid-open No. 51-107121 and Japanese Patent Laid-Open No. 59-215.
There is a method, as described in No. 008 and Japanese Patent Publication No. 60-48806, in which the magnetic field applied to the recording film is modulated according to the information to be recorded. The present invention relates to an improvement of a magneto-optical recording device using this magnetic field modulation recording method.

[Problems to be Solved by the Invention] Conventionally, in an example of overriding using a magnetic field modulation recording method, an electromagnetic coil for generating a magnetic field is installed on a disk, and a modulated magnetic field is applied. The distance between the two is 0.1mm to 0.4m
It was fixed at about m. In this case, the recording frequency is 0.
There was a problem in that it was not possible to record signals at a frequency of about several MHz, which was 5 MHz or less.

The purpose of the present invention is to solve the above problems, to be able to record signals of about several MHz, and to have both the override function, which is an advantage of magnetic disks, and the high density and large capacity, which are advantages of optical disks. An object of the present invention is to provide a magneto-optical storage device.

[Means for Solving the Problems] In order to achieve the above object, in the present invention, an optical head and a magnetic head are opposed to each other by sandwiching a record carrier, and a floating magnetic head is used as the magnetic head, and the substrate of the record carrier is Recording is performed by irradiating light with an optical head from the side and applying a magnetic field whose polarity is reversed or whose intensity is modulated according to the recording information using the magnetic head from the magneto-optical recording film side.

The floating magnetic head has a wide effective magnetic field application area (0,2
It consists of a rad core (mm x 0.5 mm) and a slider with a large flying height (1 μm or more) even at low linear speeds. moreover,
The magnetic head is characterized by having a structure in which a U-shaped magnetic core is embedded in a non-magnetic slider.

[Function] The floating magnetic head used in the present invention has a much wider effective magnetic field application area than conventional magnetic heads, for example, 0.2
If it is about mm x 0.5 mm, it is easy to align the aperture spot and the magnetic head, and it is stable against temperature changes and vibrations.

Further, if the flying height is 1 μm or more, so-called head crashes due to dust or the like hardly occur, and the device can be used in a normal office environment. Moreover, when such a head core with a wide effective magnetic field application area is used, the magnetic field strength hardly attenuates even at a position 10 to 20 μm away from the end face of the head core, so the surface of the magneto-optical recording film has a thickness of about 5 to 10 μm. A protective film can be formed. In addition, unlike conventional coated magnetic disks, etc., a protective film can be coated purely for protection without containing magnetic powder, making the protective cord extremely durable and further improving environmental resistance and reliability. can be improved.

In the floating magnetic head of the present invention, since only the head core portion is made of a magnetic material, it is possible to reduce inductance. This shortens the magnetic field reversal time and enables high frequency recording. Further, by forming the helad core portion into a U-shape, the efficiency of applying the magnetic field can be improved. Furthermore, by making a portion of the slider from a non-magnetic material, it is possible to prevent the effective magnetic field strength applied to the magneto-optical recording film from decreasing due to the magnetic field leaking from the diaphragm lens actuator or the like.

Information is recorded by irradiating the magneto-optical recording film with high-power laser light from the substrate side using an optical head, and at the same time, from the magneto-optical recording film side, a modulated magnetic field whose polarity is reversed or whose intensity is modulated according to the recorded information is sent by a magnetic head. This is done by applying a voltage. This allows new signals to be overwritten while erasing old signals. That is, it is possible to realize a magneto-optical recording device that has both the high density and large capacity of an optical disk and the override function of a magnetic disk, without substantially impairing the non-contact characteristic of optical recording.

[Example 1] An example of the present invention will be described below with reference to FIG. In the figure, reference numeral 1 denotes a magneto-optical disk which is a rotating recording carrier, and has a magneto-optical recording film 101 having a magneto-optic effect and a protective film 102 on a disk-shaped transparent substrate 103. For example, the light emitted from the light source consisting of the semiconductor laser 2 is
The collimating lens 3 converts the light into a parallel light beam, which enters the diaphragm lens 5 via the beam splitter 4.

The light beam narrowed down by the lens 5 is directed to the disk substrate 1.
It enters the disk from the 03 side and hits the recording film 101 directly ffl
A reduced spot of approximately 1 μm is formed. Aperture lens 5
The light spot follows the vertical movement of the disk 1 so that the focus is always on the recording film, and it also follows the eccentricity of the information recording terrace on the disk so that the light spot always falls on the desired track.

It is attached to the actuator 6. The reflected light from the disk 1 passes through the aperture lens 5, is reflected by the beam splitter 4, and is transmitted by the beam splitter to the magneto-optical signal detection optical system 8 and the light spot control signal detection optical system 9, which detects defocus and track deviation. be guided.

An example of the magneto-optical signal detection optical system 8 is shown in the figure.

This is a differential signal detection method using a λ/2 plate 801 and a polarizing beam splitter 803.

The light incident on the magneto-optical signal detection optical system 8 passes through the λ/2 plate 80
1. Passes through lens 802 and polarizing beam splitter 80
3 into each polarization component of s'p and sent to a photodetector 8.
04 and 805, respectively. The signals converted into electrical signals by both photodetectors are differentiated by a differential amplifier 10 and obtained as a magneto-optical signal.

The magnetic head 12 is placed on the recording film side, sandwiching the disk 1 and facing the optical head 11. For the sake of explanation in Figure 1, the magnetic head is 90° in the disk plane from the actual arrangement.
It is rotated and enlarged as a bird's-eye view. As will be described later, the magnetic head 12 is composed of a coil portion that applies a magnetic field to a recording film and a slider portion that levitates the entire head. During disk rotation, the magnetic head 12 is levitated by air pressure generated by the disk rotation. The flying height is 1 μm or more (preferably 2 μm)
above). With this level of flying height, head crashes caused by dust and the like, which are a problem with magnetic disks, do not occur, and the device can be used in the atmosphere and media can be exchanged.

The magnetic head 12 is also. 510g due to support spring 13
It is pressed against the disk 1 with a certain amount of load. When the disk starts and stops rotating, the magnetic head is kept in contact with the disk.
You can use either the ct 5tart 5top) method or the method of keeping the magnetic head away from the disk until the disk rotation speed becomes constant. However, when replacing disk 1, regardless of which of the above two methods you use, Also, a moving mechanism 16 for moving the magnetic head 12 up and down is required.

The magnetic head 12 further includes an optical head 11 and a support arm 1.
5, and is configured to be able to operate in conjunction with the optical head, so that the distance between them is constant and at the same time the magnetic head is always placed directly above the optical spot on the disk.

It is not necessarily necessary to integrate the two as shown in the diagram, but
If the recording position is not integrally coupled and the recording position is moved in the radial direction of the disk, means for keeping the distance between the two constant and magnetic head moving means for placing the magnetic head directly above the optical spot are required.

The optical head 11 is moved in the radial direction of the disk by, for example, a linear motor or a step motor.

FIG. 2 shows a method of recording information. Information v! To record, the temperature of the magneto-optical recording film 101 on the disk 1 is heated to near the Curie temperature by continuously emitting light from the semiconductor laser 2 at high output as shown in FIG. 2(b), and the area irradiated with light is decreases the coercive force of At this time, the magnetic head 12 is driven by the magnetic head drive circuit 14, and a modulated magnetic field (FIG. 2(C)) whose polarity is reversed according to the recorded information (FIG. 2(a)) is applied to the magneto-optical recording film 101. Apply voltage and record information. The recording state is shown in FIG. 2(d). In addition, if it is necessary to change the applied magnetic field strength in order to keep the recording conditions constant regardless of changes in the inner or outer circumference of the disk or laser output, in addition to polarity reversal, one intensity modulation or a direct current bias component to the magnetic field can be applied. Add. According to this method, even if new information is recorded in the area where information is already recorded, the old recorded information will not remain, and it is possible to erase the old information by overwriting, that is, by overwriting the information. Become.

Here, the magnetic head, which is the main component of this embodiment, will be explained in detail.

The magnetic herad 12 has a large flying height even when the linear velocity is low,
In addition, a floating magnetic head with a wide effective magnetic field application area is used. From the perspective of preventing head crashes due to dust etc., the flying height should be 1 μm or more (preferably 2 μm or more), and from the perspective of alignment between the optical spot and the magnetic head, the effective magnetic field application area of the head core should be 0.1 mm x 0.1 mm or more m x 1
mm or less, preferably 0.1 mm x 0.1 mm or more, 0
．． The size shall be 2 mm x 0.5 mm or less.

FIG. 3 shows the structure of a floating magnetic head according to the present invention. FIG. 3(a) is a bird's eye view of the magnetic head.

FIG. 3(b) is a developed view thereof. The magnetic core 301 is made of a magnetic material such as Mn-Zn, and has a rectangular shape.

Furthermore, this magnetic core 301 is embedded in a slider 302 made of a non-magnetic material such as ceramic.

In conventional magnetic heads used for magnetic disks and the like, a magnetic core and a slider are integrally fabricated, and a portion of the slider is also made of a magnetic material. If this magnetic head is used as is in a magneto-optical disk, for example, the magnetic field leaking from the aperture lens actuator will concentrate on a part of the slider, so depending on the polarity of the magnetic field generated from the magnetic core, both magnetic fields will work in a direction that cancels each other out, causing recording. If the slider 302 is made of a non-magnetic material, the effective magnetic field strength applied to the film is reduced, the above phenomenon does not occur, and the magnetic field generated from the magnetic core can be efficiently applied to the recording film. .

Furthermore, since the structure can have a smaller amount of magnetic material than when the entire magnetic head is made of magnetic material, the inductance of the magnetic head can be lowered, making it possible to record higher frequencies. .

The magnetic head 12 is installed so that one end 301a of the U-shaped magnetic core is directly above the narrowing spot 501. Since the lines of magnetic force have a distribution as shown in the figure, a magnetic field in the opposite direction to 301a is generated directly below one end 301b of the U-shaped magnetic core. By utilizing this, by arranging focused spots just below both ends 301a and 301b of the U-shaped magnetic core, one can be used as a recording spot and the other as an erasing spot, allowing override using two optical spots. You can also do this.

The winding fi303 of the magnetic core is the winding of the core directly above the narrowing spot of the U-shaped magnetic core. Thereby, the strength of the magnetic field generated at the end surface 301a can be increased, and the efficiency of magnetic field generation can be increased.

The closer the winding 303 is located to the slider sliding surface, the higher the magnetic field generation efficiency and the lower the inductance of the magnetic head. From this point, the thickness of the portion of the slider 302 that supports the magnetic core 303 (
If the portion indicated by d in the figure is not sufficient from the viewpoint of mechanical strength, a structure is adopted in which both the upper and lower sides of the U-shaped magnetic core are supported as shown in FIG.

In the above description, the slider has a so-called two-rail structure, but the present invention is also applicable to sliders with other structures. Regarding the position of embedding the magnetic core, in this embodiment, it is placed on one rail near the air outflow end, but it can be placed in the center of two rails, or in the center between the outflow end and the inflow end. It goes without saying that the present invention is applicable even in the position of .

[Effects of the Invention] As explained above, according to the present invention, the magnetic field generation efficiency can be improved and the inductance of the magnetic coil can be reduced, so that high-speed magnetic field modulation recording can be performed with low current.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the overall configuration of the device according to the present invention, and FIG.
The figure is a diagram showing another embodiment of the diagram showing the recording principle of magnetic field modulation recording. DESCRIPTION OF SYMBOLS 1... Disk, 2... Semiconductor laser, 3... Collimating lens, 4... Beam splitter, 5... Stopping lens, 8... Magneto-optical signal detection system, 9... Light spot side (Wholesale signal detection system, 11...optical head, 12...
magnetic head. System 1 TiJ Nod Noko j and ≧m 9th edition Botu 22 manuscript [L No,? ? Te 2 Skuga cho (Yu 2nd (tl) Word Otsu (Jurei 4Y Gu ξne 4ya-) /j 4th Mogu θ2 Procedure Amendment Book

Claims (1)

[Claims] 1. A magnetic field whose polarity is reversed or whose intensity is modulated according to recorded information is applied to the magneto-optical recording film on the record carrier by a floating magnetic head, and the floating magnetic head is placed between the recording carrier and the magneto-optical recording film. In a magneto-optical storage device that records information by continuously irradiating high-output laser light from an optical head facing the recording medium, the magnetic head includes a magnetic core that applies a magnetic field to the recording carrier and a magnetic head that connects the magnetic core to the recording medium. A magneto-optical storage device characterized in that a floating slider is made of different materials. 2. The magneto-optical storage device according to claim 1, wherein the magnetic core is a magnetic material and the slider is a non-magnetic material. 3. The magnetic core according to claim 1, wherein the magnetic core is U-shaped, and the magnetic field is applied to the record carrier by narrowing one end of the core and placing it directly above the laser spot. Magneto-optical storage device. 4. Claim 1, characterized in that the winding of the magnetic core is provided at the end of the core on the side that applies a magnetic field to the record carrier, and is disposed close to the sliding surface of the slider. Magneto-optical storage device as described in .