JPH11110842A - Read out device of magnetic recording signal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately read out the information independently of a relative velocity between a medium and a head by furnishing the light passing part on a soft magnetic film close to a magnetic recording medium for making a light beam to pass through the magnetism transfer part to be transferred from the magnetic record medium, and providing the floating area on the surface confronted with the medium. SOLUTION: A pair of rails 1a, 1b is provided on the surface confronted with a magnetic disk 8, and a chip 4 having a perpendicularly magnetizing soft magnetic film 3 of garnet film on a transparent GGG garnet substrate 2 is fitted into a part of the rail 1b. A center air path putting between the rails 1a, 1b, a side air path 1c between the rail 1a and the side edge of a slider 1, and a side air path 1e between the rail 1b and the side edge of the slider 1 are respectively provided. When the magnetic disk 8 is run, the air flows in the running direction through each air path to float the slider 1 from the magnetic disk 8, and the floating area of the slider 1 is formed by the air pathes 1c-1d, and also a light passing small hole 5 for converging the light beam 7 is provided on a magnetizing part transferred on the soft magnetic film 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention magnetically transfers a signal recorded on a magnetic recording medium to a head having a soft magnetic film,
The present invention relates to a magnetic recording signal readout device for reading this out by light.

[0002]

2. Description of the Related Art Conventionally, as a device for reading a magnetic signal recorded on a magnetic recording medium, a magnetic signal is read by an induction type head utilizing magnetic induction. As a device for reading a recorded magnetic signal, a so-called floating magnetic head which performs recording and reproduction while slightly floating on a magnetic disk is generally used.

In recent years, hard disk drives have tended to be smaller and higher in density. For this reason, the recording area per bit is becoming smaller and smaller, so that the recorded magnetic signal is also smaller and the signal-to-noise ratio is degraded. Further, the inductive head has a problem in that the signal output at the time of reading depends on the peripheral speed of the disk, so that the peripheral speed is reduced due to the miniaturization of the disk, and the sensitivity at the time of reading is reduced. For this reason, an MR head using an MR element capable of obtaining a read output without depending on the peripheral speed of a disk as a reproducing head has been used. However, the track width of the MR head becomes smaller as the track density becomes higher due to the higher density of the hard disk drive. Therefore, the leakage magnetic field of the magnetic signal recorded on the magnetic recording medium becomes weaker, and the reproduction output at the time of reading also decreases. And the signal-to-noise ratio is reduced.

As a head for reading a magnetic signal recorded on a magnetic recording medium, an inductive head as described above or an M-type head is used.
In addition to the MR head using the R element, instead of directly reading the magnetic signal recorded on the magnetic recording medium using the soft magnetic film, the signal transferred to the soft magnetic film is optically read,
The use of a soft magnetic film as a head when reading a magnetic signal is described in, for example, Japanese Patent Publication No. 4-14426, Japanese Patent Application Laid-Open No. Sho 61-214261, Japanese Patent Application Laid-Open No. 62-75955, etc. It is.

[0005] Instead of directly reading a magnetic signal recorded on a magnetic recording medium using such a soft magnetic film, a signal transferred to the soft magnetic film is optically read out, and a read head is constituted by a magnetic recording medium. Even if the leakage magnetic field of the magnetic signal recorded on the medium becomes weaker, the signal-to-noise ratio does not decrease as compared with the case of reading with the MR head, and thus it is suitable as a magnetic recording signal reading device. Further, if such a reading device is used, it is possible to cope with further higher density of a magnetic signal to be recorded on a magnetic recording medium.

[0006]

However, instead of directly reading out the magnetic signal recorded on the magnetic recording medium by using the above-mentioned soft magnetic film, the signal transferred to the soft magnetic film is optically read out, and the read head is used. A configuration relating to the reproduction of a magnetic signal recorded on a disk-shaped magnetic recording medium is described in the above-mentioned Japanese Patent Application Laid-Open No. 61-214261, but this configuration is applied to a magnetic disk used in a hard disk device. No consideration has been given to the configuration for reading the recorded magnetic signal. Japanese Patent Application Laid-Open No. 62-75955 discloses a configuration of a recording / reproducing head for a double-layer perpendicular magnetic recording medium or the like of a magnetic disk drive. The laser signal is obliquely incident on the garnet film because the magnetic signal recorded on the magnetic recording medium is transferred to the garnet film that is magnetized inside through the main magnetic pole film, for example, the permalloy film. It was unavoidable that the configuration would be complicated in a limited space, such as the necessity to make it work. The present invention has been made in view of the above circumstances,
The present invention relates to a reading device for reading a magnetic signal recorded on a magnetic recording medium, and more particularly to providing a reading device having a simple configuration for directly transferring a magnetic signal recorded on a magnetic disk used in a hard disk device to a soft magnetic film for reproduction. The purpose is to do.

[0007]

According to the present invention, in order to achieve the above object, according to the first aspect of the present invention, a signal recorded on a magnetic recording medium is magnetically transferred to a soft magnetic film and this is optically transferred. In the reading device of the magnetic recording signal read by
A soft magnetic film which is magnetically transferred in response to magnetic leakage flux recorded on a magnetic recording medium, and which is disposed on a surface of the soft magnetic film which is not opposed to the magnetic recording medium and holds the soft magnetic film. A transparent substrate, and the soft magnetic film is close to the magnetic recording medium, and has a light passing portion that passes a light beam to a magnetic transfer portion transferred from the magnetic recording medium generated on the soft magnetic film,
And a slider having a flying area formed on a surface facing the magnetic recording medium. The invention according to claim 2 is the invention according to claim 1.
Wherein the transparent substrate holding the soft magnetic film is provided in a small hole opening serving as a light transmitting portion opened in the slider, and a magnetic recording signal reading device is provided. According to a third aspect of the present invention, there is provided the magnetic recording signal reading device according to the first aspect, wherein the transparent substrate holding the soft magnetic film is made of the same material as the material constituting the slider. . According to a fourth aspect of the present invention, in the first aspect, a permalloy film that controls the magnetic domain of the soft magnetic film and serves as a reflective film is applied to a surface of the soft magnetic film facing the magnetic recording medium. And a device for reading a magnetic recording signal. According to a fifth aspect of the present invention, there is provided the magnetic recording signal according to the first aspect, wherein the soft magnetic film is a garnet film grown on a GGG (gadolinium, gallium, garnet) single crystal substrate. Of the present invention. According to a sixth aspect of the present invention, in the first aspect, the flying area is provided on a surface of the slider facing the magnetic recording medium, and is formed along the running direction of the magnetic recording medium at intervals. The present invention provides a magnetic recording signal readout device comprising a book rail and at least an air passage interposed between the rails. According to a seventh aspect of the present invention, there is provided the magnetic recording signal reading device according to the sixth aspect, wherein the soft magnetic film is provided on the rail.

[0008]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a configuration diagram of a magnetic recording signal reading device according to a first embodiment of the present invention. FIG. 2 is a perspective view showing the back surface of the slider 1 of FIG. 1 facing the magnetic recording medium. As a configuration of a device for reading a magnetic signal recorded on a magnetic recording medium, for example, a magnetic disk 8, the slider 1 has a structure in which the slider 1 flies above a predetermined rotation speed of the magnetic disk like a conventional floating magnetic head. The slider 1 is supported by a slider support (not shown) made of a well-known spring plate material.

The slider 1 is made of calcium titanate. As shown in FIG. 2, a pair of rails 1a and 1b are formed on the surface facing the magnetic disk 8, and one of the rails 1a and 1b is formed.
b, for example, GG transparent with visible light or infrared light
G garnet (gadolinium, gallium, garnet)
For example, (SmLuBi) ₃ (F
A chip 4 on which a soft magnetic film 3 made of a vertically magnetized garnet film such as eGa) ₅ O ₁₂ is mounted. A central air passage 1d is formed between the two rails 1a and 1b, a side air passage 1c is formed between the rail 1a and the side edge of the slider 1, and a side air passage 1c is formed between the rail 1b and the side edge of the slider 1. An air passage 1e is formed. FIG. 3 shows a detailed sectional structure of the chip 4. In FIG. 3, a light-transmitting protective film 2a is applied to the surface of the substrate 2 to prevent the light beam 7 from being reflected on the surface of the substrate 2 and protect the surface of the substrate 2, and the soft magnetic film 3 On the magnetic disk 8 side, a reflective film 3a made of a material that reflects light, such as an aluminum thin film, and a protective thin film 3b for protecting the same.
Is attached. The slider 1 is provided with a small hole 5 so that a light beam 7 generated from a light source generator (not shown) is converged on the soft magnetic film 3 by an objective lens 6 disposed above the slider 1. I have. As described above, in the present invention, the slider 1 has a structure such that it floats above a predetermined rotation speed of the magnetic disk as in the conventional floating magnetic head, and the structure includes the soft magnetic film 3 held by the slider. A read head A for reading a magnetic recording signal is configured.

FIG. 4 is a conceptual diagram showing an example of an entire apparatus for reading a magnetic signal recorded on the magnetic disk 8 by magnetization. The information recorded on the magnetic recording medium such as the magnetic disk 8 may be an analog signal or a digital signal. In FIG. 4, reference numeral 10 denotes a light source generator. The light source generator 10 can use, for example, a laser. 11 is a polarizing prism, 12 is a beam splitter, 13 is a polarizing prism, and 14 is a photodetector. FIG.
The operation of the apparatus shown in FIG. 1 will be described. The magnetic disk 8 is advanced in the direction of the arrow. At this time, the air near the surface of the magnetic disk 8 flows in the same direction as it travels, and flows into the side air passages 1c and 1e including the central air passage 1d. When the traveling speed of the magnetic disk 8 exceeds a predetermined value, when the air flows through these three air passages, a levitation force for floating the slider 1 from the surface of the magnetic disk 8 acts on the slider 1, and the slider 1 lifts up slightly, and the slider 1 is lifted. In a non-contact state. When the leakage magnetic flux leaking from the magnetized portion recorded on the magnetic recording layer 8a on the surface of the magnetic disk 8 passes through the soft magnetic film 3, the leakage magnetic flux magnetizes the magnetic domain of the soft magnetic film 3, and the soft magnetic film 3 The magnetization of the magnetic domain moves in the same direction as the magnetic recording layer 8a moves. The vicinity of the magnetized portion transferred onto the soft magnetic film 3 where the light beam 7 is converged is referred to as a magnetic transfer portion, and the small holes 5 of the slider 1 through which the light beam passes form a light passing portion, and a central air passage is formed. 1d, side air passages 1c, 1e
Forms a flying area of the slider 1.

On the other hand, the light beam 7 emitted from the light source generator 10 passes through a polarizing prism 11, is converted into linearly polarized light, passes through a beam splitter 12, is converged by an objective lens 6, and is converged by a soft magnetic film 3. The above magnetized portion irradiates the transferred magnetic transfer portion, passes through it, and is converged on the reflective film 3a. The converged light is reflected by the reflection film 3a, passes through the magnetized portion again in the reverse direction, is reflected by the beam splitter 12 in the direction of the polarizing prism 13, passes through the light, and reaches the photodetector 4. As described above, the light beam 7 passes through the portion where the magnetization portion of the soft magnetic film 3 moves twice, and is applied by the Faraday effect according to the magnitude of the magnetization of the magnetic domain, and the rotation angle of the polarization plane thereof Changes according to the signal of the magnetized portion. This change is read by the photodetector 14.

In the configuration shown in FIG. 3, when the magnetic disk 8 is rotated at a linear velocity of about 10 m / s, for example,
In order to make the distance between the disk and the magnetic disk 8 100 nm,
The size of the slider 1 was 2.8 mm in width * 4.5 mm in length, the rails 1a and 1b were 0.26 mm in width and 0.04 mm in depth. The reading of the magnetic signal recorded on the magnetic disk 8 is performed by converging the light beam 7 by the objective lens 6 on the portion of the soft magnetic film 3 where the state of the magnetic domain has changed by the leakage magnetic field from the magnetic signal. The magnetic signal is read out by the magneto-optical effect described above.

In this embodiment, a substrate 2 and a soft magnetic film 3 formed on the substrate 2 are formed on a GGG (gadolinium, gallium, garnet) single crystal substrate 2 by a soft magnetic film 3 made of a garnet film which is vertically magnetized. Was used after crystal growth. The garnet film was formed by a known LPE (liquid phase epitaxial) method. Garnets have high magnetic and light conversion efficiencies, which can increase the signal-to-noise ratio during playback with light. In this embodiment, a garnet film having a perpendicular magnetization is grown on a GGG single crystal substrate. However, a garnet film having an in-plane magnetization may be used.

Although the slider 1 in this embodiment is made of calcium titanate, it is not limited to this, and it goes without saying that the slider 1 may be made of barium titanate, altic, zirconia, sapphire or the like. .

FIG. 5 is a configuration diagram showing a second embodiment of the present invention. The difference from the first embodiment is that the slider 1
Are formed of the same material as the substrate 2. Therefore, a new slider material is not required, the number of components can be reduced, and an operation for attaching the substrate 2 to the slider 1 is unnecessary. In this embodiment, since the slider 1 is made of a GGG single crystal substrate, the slider 1 has good light transmittance. Therefore, without providing a small hole for allowing a light beam to pass through, the light has a refractive index that is approximately equal to that in air. Since it is twice as large, an objective lens having a shorter focal length than the objective lens 6 in the configuration of FIG. 1 can be used, so that higher resolution can be obtained. Although not shown in the figure, a reflective and protective thin film is formed on the lower surface of the soft magnetic film 3.

FIG. 6 is a configuration diagram showing a third embodiment of the present invention. The difference from the first embodiment is that the soft magnetic film 3
The difference is that a permalloy film 9 is formed thereon. Generally, an aluminum film or a titanium film is formed as a reflective film on the soft magnetic film 3 shown in FIG. 1, and a SiO ₂ film is further formed as a protective film. A thick permalloy film 9 is formed to act as a magnetic domain control film of the soft magnetic film 3 and also act as a reflection film. If the magnetic domain control is not performed, the magnetic domain of the soft magnetic film 3 is likely to be slightly moved or deformed. If the magnetic domain is slightly moved or deformed, it becomes a noise component at the time of reading and the signal-to-noise ratio is reduced. For this reason, by providing the permalloy film 9 on the soft magnetic film 3 and controlling the magnetic domain, it is possible to suppress the fine movement or deformation of the magnetic domain of the soft magnetic film 3, so that the noise component at the time of reading can be reduced. The noise ratio does not decrease. Further, the permalloy film 9 can also function as a reflection film.

Although the present invention has been described with reference to the above embodiment, various modifications and applications are possible within the scope of the present invention, and these modifications and applications are excluded from the scope of the present invention. is not.

[0018]

As described above in detail, according to the first aspect of the present invention, the information recorded on the magnetic recording medium can be accurately read regardless of the relative speed between the magnetic recording medium and the read head. In addition to being able to read, a floating area is formed on the slider of the read head,
It is easy to apply to a hard disk as a magnetic recording medium. According to the second aspect of the invention, in addition to the effect of the first aspect, it is possible to configure a reading device that can perform a reading operation smoothly even if the slider is formed of an opaque substance. According to the third aspect of the present invention, in addition to the effect of the first aspect, the slider is not provided with a small hole through which the light beam passes, and thus the configuration of the slider is simplified. According to the fourth aspect of the invention, in addition to the effect of the first aspect, since the magnetic domain control is performed by providing the permalloy film on the soft magnetic film, the fine movement or deformation of the magnetic domain of the soft magnetic film can be suppressed, and the reading can be performed. Since the noise component at the time can be reduced, the signal-to-noise ratio does not decrease. Further, the permalloy film can also function as a reflection film. According to the fifth aspect of the invention, in addition to the effect of the first aspect, since the slider is made of a GGG single crystal substrate, the slider has good light transmittance, and therefore does not have a small hole for transmitting a light beam. Since the refractive index of the light is about twice as large as that in the air, an objective lens having a shorter focal length than the objective lens 6 in the configuration of FIG. 1 can be used, so that higher resolution can be obtained. According to the sixth aspect of the invention, in addition to the effect of the first aspect, a strong flying force is generated by the plurality of rails and the air passages sandwiched between the rails, and the slider has a very small distance from the magnetic recording medium. Therefore, it is possible to read the information recorded on the magnetic recording medium without any damage due to the contact. According to the seventh aspect of the invention, in addition to the effects of the first and sixth aspects, the soft magnetic film can be brought closer to the magnetic recording medium from the air passage surface of the slider by the depth of the rail,
The information recorded on the magnetic recording medium can be read more reliably.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a magnetic recording signal reading device and its periphery according to a first embodiment of the present invention;

FIG. 2 is a perspective view showing a flying region of a slider.

FIG. 3 is a sectional view of a chip 4;

FIG. 4 is a conceptual diagram showing an example of an entire apparatus for reading a magnetized portion recorded as data on a magnetic disk.

FIG. 5 is a configuration diagram showing a magnetic recording signal reading device and its periphery according to a second embodiment of the present invention;

FIG. 6 is a configuration diagram showing a magnetic recording signal reading device and its periphery according to a third embodiment of the present invention.

[Explanation of symbols]

 A ... Read head 1 ... Slider 1a ... Rail 1b ... Rail 1c ... Side air passage 1d ... Central air passage 1e ... Side air Passage 2 ··· Substrate 2a ··· Transparent protective film 3 ···· Soft magnetic film 3a ··· Reflective film 3b ··· Protective thin film 4 ····· Chip 5 ··· ... Small hole 6 ... Objective lens 7 ... Light beam 8 ... Magnetic disk 8a ... Magnetic recording layer 9 ... Permalloy film 10 ... Light source generator 11 ···· Polarizing prism 12 ····· Beam splitter 13 ···· Polarizing prism 14 ····· Photodetector

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tomoaki Terada 173-1 Asana-machi, Asaba-cho, Iwata-gun, Shizuoka Pref. Minebea Development Technology Center (72) Inventor Tatsuo Nomura 2200-2 Toyosawa, Fukuroi-shi, Shizuoka Pref. Incorporated in Shizuoka University of Technology (72) Inventor Hiroshi Honda 173-1 Asana-cho, Asaba-cho, Iwata-gun, Shizuoka Prefecture Inside Minebea Development Technology Center (72) Inventor Rikio Tsuchiya Asana-cho, Iwata-gun, Shizuoka Prefecture 1743-1 Minebea Co., Ltd. Development Technology Center (72) Inventor Mitsuru Tomita 173-1 Asana-cho, Iwata-gun, Shizuoka Prefecture Minamibea Co., Ltd. Development Technology Center (72) Inventor Takashi Furutani Fukuroi, Shizuoka Prefecture 2200-2 Toyosawa Shizuoka Institute of Technology (72) Inventor Toshihide Kakezawa 1-3-3 Shintoda, Hamamatsu City, Shizuoka Prefecture Hamamatsu Industrial Technology Center, Shizuoka Prefecture In over (72) inventor Shingo Kato Hamamatsu, Shizuoka Prefecture Shinmiyakoda 1-3-3 Shizuoka Prefecture Hamamatsu Industrial Technology within the center

Claims (7)

[Claims] An apparatus for magnetically transferring a signal recorded on a magnetic recording medium to a soft magnetic film and reading the signal by light, wherein the signal is read in response to a magnetic flux leaking from the magnetic recording medium. A soft magnetic film to which this is magnetically transferred, a transparent substrate that is arranged on the surface of the soft magnetic film that does not face the magnetic recording medium and holds the soft magnetic film, A slider having a light passing portion for allowing a light beam to pass through a magnetic transfer portion transferred from a magnetic recording medium generated on the soft magnetic film, and having a flying area formed on a surface facing the magnetic recording medium; A magnetic recording signal reading device comprising: 2. A magnetic recording signal readout according to claim 1, wherein the transparent substrate holding the soft magnetic film is provided in a small hole opening portion serving as a light transmitting portion opened in the slider. apparatus. 3. The magnetic recording signal reading device according to claim 1, wherein the transparent substrate holding the soft magnetic film is made of the same material as that of the slider. 4. A magnetic recording medium according to claim 1, wherein a permalloy film serving as a reflection film is formed on the surface of the soft magnetic film facing the magnetic recording medium, while controlling the magnetic domain of the soft magnetic film. A device for reading recorded signals. 5. An apparatus according to claim 1, wherein said soft magnetic film is a garnet film grown on a single crystal substrate of GGG (gadolinium, gallium, garnet). 6. The flying area is provided on a surface of the slider facing the magnetic recording medium, and is provided with a plurality of rails formed along the running direction of the magnetic recording medium at intervals and at least sandwiched between these rails. 2. The magnetic recording signal reading device according to claim 1, further comprising: 7. The apparatus according to claim 6, wherein the soft magnetic film is provided on the rail.