JPH02152016A - Recording of reproducing method of information recording medium - Google Patents

Abstract

PURPOSE:To keep the gap between an optical head and an information recording medium constant with a high precision by using a slider provided with an electrode part and giving positive or negative electric charged in accordance with the variance of the quantity of reflected light to correct the vertical position of the information recording medium. CONSTITUTION:The laser light emitted from a semiconductor laser 31 is condensed through a collimator lens 34, a polarizing prism splitter 37, and an objective lens 36 and is focused on an information recording medium 35. The laser light reflected on the information recording medium 35 passes the objective lens 36 again and is polarized by the polarizing prism splitter 37 and is turned at right angles. This laser light is condensed by a cylindrical lens 38 and the focus error is detected by a four-divided photodetector 39. This detection signal is fed back to a voltage source 33, and electric charge is given from the voltage source 33 to a transparent electrode 31 provided on the surface of the slider 32 for the purpose of correcting the position of the information recording medium 35 to the focusing distance, and the vertical position of the information recording medium 35 is corrected.

Description

[Detailed Description of the Invention] [Field of the Invention] Ungenerated IJ is a recording or +IT production method of an information recording medium comprising a recording layer on which information can be read, written and/or erased by a laser. It is related to.

More specifically, the present invention relates to a method for recording or reproducing an information recording medium in which the recording layer is formed on the surface of a flexible resin film.

[Technical Background of the Invention A] In recent years, disc-shaped information recording media using high energy density beams such as laser beams have been developed and put into practical use. This information recording medium is called an optical disk, and can be used as a video disk, an audio disk, a large-capacity still image file, and a large-capacity computer disk/memory.

The basic structure of an optical disk is a disk-shaped transparent substrate made of plastic or the like, and a recording layer provided thereon from which information can be read, written, and/or erased. The surface of the substrate on which the recording layer is provided is coated with an undercoat layer or an intermediate layer made of a polymeric material in order to improve the flatness of the substrate, improve the adhesion with the recording layer, and improve the sensitivity of the optical disc. Sometimes it is provided.

In recent years, disc-shaped information recording media (optical discs) have been developed in which a flexible resin film is used as a substrate and the recording layer is formed thereon. Information recording media using such flexible resin films are also rotated at high speed in the same way as conventional video conference discs, audio φ discs, etc.
It is used to write, read, or erase information.

Furthermore, the flexible resin film described above is also used as a substrate for magneto-optical recording media, and in this case, the focusing servo that maintains a constant distance between the disk and lens, which is used in ordinary optical disks, is not used. do not have. Therefore, during recording and reproduction, etc., it is necessary to maintain a distance of 1 mm or more between the disk (perpendicular magnetization ll2) and the optical fiber or coil, especially the distance between the disk and the coil, to avoid contact between them. In this way, when the distance between the disk and the optical head or coil is 1 mm or more, it is necessary to increase the coil current f1, electric power, etc. in order to record on the magneto-optical recording medium, and for this reason, the circuit that drives the coil needs to be increased. The disadvantage is that it becomes complicated and complicated.

In order to stably bring the distance between the above-mentioned magneto-optical disk (perpendicular magnetization v) and the optical head and coil,
The following method is proposed in Japanese Patent No. 632. In this method, for example, information is recorded using an apparatus having a configuration as shown in FIG. 5. The apparatus shown in FIG. The heated recording and reproducing light beam 52 and the light irradiated from it.
A slider 55 that makes the disk 54 float by forming a circulating gas layer between the light beam 59 and the disk.
, a coil 53 embedded in a slider 55, and a fixing plate 56 which is an auxiliary means for stably floating the disk 54. When the disk 54 rotates, the air between the disk 54 and the fixed plate 56 is expelled to the outside due to the centrifugal force of the air, and the disk 54 is moved away from the fixed plate 56.
is attracted to. On the other hand, in the slider 55, air is forced into the wedge-shaped gap formed between the slider surface and the disk 54, forming a circulating gas layer, and positive pressure is generated, causing the disk 54 to
4 floats up from the slider 55.

The disk 54 receives negative pressure from the fixed plate 56 and the slider 55.
The distance from the slider 55 is several μm. In this way, the slider forms a circulating gas layer between the optical disk and the optical head, and as a result, the distance is stabilized to several ILm.

The above theory of forming a flowing gas layer can also be applied to ordinary flexible optical discs that do not use magnetic materials, and by using the above slider, the distance between the optical disc and the optical head can be reduced to a range of several gm. Since it is stable at , good focusing of the information recording medium is possible. However, although such stable focusing is performed with good accuracy near the radial center of the disc-shaped optical disc, this distance becomes unstable the closer you get to the outside and inside of the disc; for example, the distance becomes larger on the outside. easy. Therefore, in the above method, the area on the optical disc where recording is performed is extremely small, and it cannot be said that the size of the optical disc is effectively utilized.

[Object of the invention] The unreleased IJi can be recorded on or reproduced from an information recording medium by a simple method without using a conventional focusing servo while maintaining a constant distance between an optical head and the information recording medium with high precision. The purpose is to provide a method for

Furthermore, the present invention provides a recording or reproducing method for an information recording medium that makes it possible to expand the recording area of the information recording medium by using the above-mentioned focusing control method that is different from the conventional focusing servo. purpose.

[Summary of the Invention] The present invention provides an optical head having a light emitting part and a light receiving part, and a slider on the top, which is arranged close to one surface of a rotating flexible information recording medium. A circulating gas layer is formed between the slider and the optical disk, and the gap therebetween is maintained substantially constant, thereby emitting light from one light emitting portion while maintaining the height of the information recording medium substantially constant. , a method for recording or reproducing an information recording medium, which includes receiving reflected light from the information recording medium with a light receiving section, in which a slider provided with an electrode part is used as the slider, and a slider having an electrode section is used as the slider; Accordingly, a change in the distance between the one-nuclear slider and the information recording medium is read, and a positive or negative charge corresponding to the change in the amount of reflected light is applied to the electrode of the slider so as to compensate for this change, A method for recording or reproducing an information recording medium is characterized in that the distance between the slider and the information recording medium is maintained constant with high precision by varying the height of the information recording medium.

The recording or reproducing method of the information recording medium of the present invention is as follows.

1) The method for recording or reproducing information on an information recording medium, characterized in that the slider is a slider in which a thin film of a transparent II electrode is provided on the surface of a convex portion of a plano-convex lens made of glass.

2) The variation in the distance between the slider and the information recording medium is 2
．． The above method for recording or reproducing an information recording medium, characterized in that the recording or reproducing method is controlled to be 5JLm or less.

[Effects of the Invention] The recording or reproducing power method of the information recording medium of the present invention uses a flexible information recording medium and utilizes the theory of the formation of a flowing gas layer to solve the disadvantage of disc-shaped optical disks. This eliminates the problem of poor focusing on the inner or outer circumferential side.

That is, the present invention reads fluctuations in the amount of reflected light from the recording layer of an information recording medium, and applies positive or negative charges according to the fluctuations to the surface of the slider by providing, for example, a transparent +J'N electrode. As a result, the slider surface is charged with an electric charge, and electrostatic attraction (or repulsion) with the electric charge on the information recording medium surface is used to move the slider, whether it is on the inner circumference side or the outer circumference side, of the disc-shaped optical disk. Recording or reproduction is performed while adjusting the distance between the information recording medium and the slider so as to maintain it constant with high precision, that is, to achieve a good focusing state.

In this way, by applying an electric charge to the slider, it is possible to perform good focusing on either the inner or outer circumferential side of the disc-shaped optical disc, and even with a simple focusing control method, it is possible to achieve excellent focusing71. You can perform precise focusing. Therefore, according to the present invention, information can be recorded and reproduced in a good focusing state in a simple manner by utilizing the above-mentioned focusing control without using the conventional focusing servo. Further, it is a recording or reproducing method for an information recording medium that allows a wide range of recording areas from the inner circumferential side to the outer circumferential side of the information recording medium to be set as a recording area.

[Detailed Description of the Invention] Thu) i:, [j The information recording medium used in I is basically a flexible resin film on one surface of which information can be recorded and reproduced using light. This is an information recording medium provided with a recording layer.

The method for recording or reproducing information on an information recording medium is to stably control the distance between the information recording medium and the optical head in an extremely close state where focusing is possible (so-called focusing control). By utilizing the theory of layer formation, this drawback has been further eliminated.

Regarding the recording or reproducing method of the information recording medium of the present invention,
This will be described in detail with reference to the attached FIGS. 1, 2-A, 2-B, 2-C, 2-D and 3.

FIG. 1 is a schematic cross-sectional view of an example of an optical disk drive equipped with an information recording medium for explaining a method for recording or reproducing one missing IJI.

FIG. 1 shows a flexible information recording medium 15, an optical disc 11 for recording and reproducing arranged under the flexible information recording medium 15. A slider 12 that floats the information recording medium 15 based on the theory of forming a circulating gas layer, a motor 14 that rotates the information recording medium 15, and a window 1 that is an opening for bringing the optical head close to the information recording medium.
6 and a cartridge 13 that covers an information recording medium 15.

FIG. 2-A is a plan view of the optical disk device used in FIG. 1. Fig. 2-A shows that a step is provided so that a circulating gas layer is easily generated between the optical disc and the upper and lower plates of the cartridge when the optical disc is mounted.
It is composed of a non-step portion 22, a step bearing portion 23 which is a step portion between the step portion and the non-step portion, an air circulation groove 24, and a window portion 26.

FIG. 2-B is a sectional view taken along the line B-B′ of FIG. 2-A, and shows a step portion 21 and a non-step portion 22 corresponding to FIG.
and air circulation grooves 24.

Figure 2-C is a cross-sectional view taken along the line CC' in Figure 2-A.
- Shows the state in which the information recording medium is installed in the device shown in Figure A,
Step part 21 and non-step part 2 corresponding to Fig. 2-A
2. Consists of a step bearing part 23 and a window part 26,
The positions of the information recording medium 25 and the slider 29 are also shown. Air flow 27 with respect to the traveling direction 25d of the medium
occurs.

2-D are cross-sectional views taken along the line DD' in FIG. 2-A, showing a state in which an information recording medium is attached to the apparatus in FIG. 2-A, and steps corresponding to those in FIG. 2-A. It consists of a section 21, a non-step section 22, an air circulation groove 24, and an information recording medium 25. Air flow 28 is generated in the traveling direction 25d of the medium.

FIG. 3 is an enlarged sectional view of the optical head 11 and its surroundings in FIG. 1. That is, the laser incidence path in the optical helad 11 consists of a semiconductor laser 31 that emits laser light, a collimator lens 34 that guides the emitted laser light, a polarizing prism splitter 37, and an objective lens 36. is condensed by the objective lens 36 and focused onto the information recording medium 35.

The reflection path includes an objective lens 36. which guides the laser beam reflected by the information recording medium 35 to detect it. It consists of a polarizing prism splitter 37, a cylindrical lens 38, and a quarter-M photodetector 39. Furthermore, the voltage @i33 to which this detection signal is fed back and its voltage source 33
charge from (charge to correct focusing distance)
A transparent electrode 30 is provided on the surface of the slider 32 to receive the signal.

In FIG. 1, when the flexible information recording medium 15 rotates, the air between the information recording medium 15 and the L side plate of the cartridge 13 is pushed out by the centrifugal force of the air.
The information recording medium 15 is sucked into the upper part of the cartridge 13. Negative pressure is thus generated between the upper plate of the cartridge and the information recording medium, and positive pressure is generated between the lower plate of the cartridge and the information recording medium, but the pressure between the two is balanced with +1 fl. The rotation becomes stable.

In order to quickly obtain such stable rotation, there is a step inside the cartridge as shown in Figures 2-A-D.
It is preferable that the iQ be eclipsed. That is, the step section 21
Due to the difference in level created by the non-step portion 22 and the function of the air circulation groove 24, when the optical disk is mounted and rotated, air flow is easily generated, and pressure is generated quickly. Thereby, stable rotation of the information recording medium can be easily obtained.

On the other hand, in the slider 12, according to the theory of flowing gas layer formation, air is forced into the wedge-shaped gap formed between the slider surface and the information recording medium 15, generating positive pressure, and the information recording medium 15 floats from the slider 12. do. The information recording medium 15 is stabilized at a point where the positive pressure generated in the space above the cartridge 13 and the positive pressure generated in the space with the slider 12 are balanced, and the distance from the slider 12 is several μm. - The focusing method described in F is performed with good viscosity near the center of the disc-shaped optical disc in the radial direction, but this distance becomes unstable as it approaches the outside and inside of the disc. It tends to get bigger. In the case of ungenerated IJ1, for example, a transparent 11 electrode as shown in FIG. 3 is provided on the surface of the slider 12 and an electric charge is applied to the electrode. By using attraction (or repulsion), the distance between the information recording medium 15 and the slider 13 is maintained constant with high precision. As a result, adjustment is carried out to achieve the above-mentioned favorable force effect, whether on the inner circumferential side or on the outer circumferential side of one disc-shaped optical disk.

That is, in FIG. 3, the laser beam emitted from the semiconductor laser 31 passes through the collimator lens 34, the polarizing prism splitter 37, and the objective lens 36.
! The light is focused on the information recording medium 35. In the information recording medium, the side facing the optical head is the recording layer side (by changing the focal length of the optical head, the side facing the optical head may be the substrate side). After the laser beam reflected by the information recording medium 35 passes through the objective lens 36 again, it is polarized by the polarizing prism splitter 37, and the laser beam is bent at a right angle. The bent laser beam is condensed by a cylindrical lens 38, and a focus error of the condensed laser beam is detected by a four-division photodetector 39. This detection signal is fed back to the voltage [33, and a charge is applied from the voltage source 33 to the transparent IJI electrode 31 provided on the surface of the slider 32 in order to correct the position of the information recording medium to the focusing distance. In this way, control is performed so that the height position of the information recording medium is corrected and the distance between the high information recording medium 15 and the slider 13 is maintained constant with high precision.

The variation in the distance between the slider and the information recording medium is 2.51.
It is preferable to control it to Lm or less for good recording and reproduction, and it is particularly preferable to control it to 2 gm or less.

Specifically, when adjusting the position of the optical head, when the information recording medium is negatively charged, if the information recording medium and the slider come too close together, a negative charge is applied to the slider and the information recording medium is moved away. Furthermore, if the information recording medium and the slider are too far apart, a positive charge is applied to the slider and the slider is controlled to approach them. By applying electric charge to the slider in this way, good focusing is possible fE whether on the inner or outer circumferential side of the disk-shaped optical disk, and extremely accurate focusing can be performed using a simple control method. can.

Note that the above explanation describes one aspect of the focusing control method used for recording or reproducing information on the information recording medium of the present invention, and includes the following! For example, a protective layer etc. may be provided on the recording layer, an intermediate layer etc. may be provided between the recording layer and the substrate, and the laser beam irradiation may be performed as described above. The optical head may be located above the information recording medium or below the information recording medium as described above.

As the resin film, recording layer, undercoat layer, etc. constituting the information recording medium of the present invention, known ones can be arbitrarily used except for the parts that are characteristic of the present invention, so these will be briefly described below. explain. [Materials for the disc-shaped resin film used in JL include acrylic resin, vinyl chloride resin, polystyrene resin, polyamide resin, polyolefin resin (e.g. polypropylene, polyethylene), polycarbonate, polyester resin ( Examples include thermoplastic resins such as polyethylene terephthalate), and polyvinylidene chloride. Preferred are polyolefin resins, polycarbonate resins, and polyester resins.

The surface of the substrate on which the recording layer is provided has improved flatness,
For the purpose of improving the adhesive strength and preventing deterioration of the recording layer, an undercoat layer (and/or intermediate layer) may be provided, and examples of the materials for the undercoat layer (and/or intermediate layer) include:
Polymer substances such as polymethyl methacrylate, acrylic acid/methacrylic acid copolymers, nitrocellulose, polyethylene, chlorinated polyolefins, polypropylene, polycarbonate, etc. UV-curable resins made of acrylic monomers, etc. Organic substances such as nidiran coupling agents: and inorganic oxides (Si02, A, 03, etc.), inorganic fluorides (M
Examples include inorganic substances such as gF2). Using the above materials, for example, a layer made of UV curable resin may be provided as an undercoat layer, and an inorganic oxide layer may be further provided thereon as an intermediate layer, or the above materials may be combined to form a single layer. More than one layer can be provided as appropriate.

In the present invention, the recording layer formed on the information recording medium is of a type (write-once type or DRAW [Direct R
(ead After Write type), and a type that allows repeated recording and erasing by utilizing phase change or changes in the direction of magnetization in the case of magneto-optical recording (Erase Machado type, that is, E-DRA W [ Eras
able-Direct Read After Wr.
ite] type).

Examples of materials used for the DRAW type recording layer include T.
e, Zn, In, Sn, Zr, An, Ti, Cu, Ge
, Au, Pt and other metals; Bi, As, Sb and other metalloids;
Semiconductors such as Si; and alloys thereof or combinations thereof can be mentioned. Compounds such as sulfides, oxides, borides, silicon compounds, carbides, and nitrides of these metals, semimetals, or semiconductors; and mixtures of these compounds and metals can also be used in the recording layer. The recording layer may further contain various known metals, semimetals, or compounds thereof as recording layer materials.

Alternatively, the recording layer may be made of a dye such as a cyanine dye.

The recording layer may be a single layer or a multilayer, and the thickness of the recording layer is generally from 100 to 50 mm in terms of optical density required for optical information recording.
In the range of 500X, preferably 150~xoooz
is within the range of

Further, when the recording layer is of the E-DRAW type, a recording layer made of the following material, which is a substance capable of causing a phase change due to temperature, is provided. At this time, a light-absorbing substance may be dispersed and contained if necessary.

Examples of the phase change include a change between a crystalline state and an amorphous state, and a change between a compatible state and a phase-separated state.

An example of a substance that can cause a state change between a crystalline state and an amorphous state is S b 100-X T e X(40(X
(60), 5b2Se, TeaX (0<x<2), 5b
Examples include metal and metalloid compounds such as -Te-Ge and 5n-Te-5e. For example, 5b
2Se is relatively in a crystalline state at room temperature and has high reflectance and low transmittance, but at high temperatures it becomes an amorphous state, resulting in lower reflectance and higher transmittance. Conversely, TeO,1 is in an amorphous state at room temperature and becomes crystalline at high temperatures. In addition to these, known metals, semimetals, and compounds thereof that undergo a state change between a crystalline state and an amorphous state can be used.

Furthermore, a typical example of a substance that can undergo a state change between a compatible state and a phase-separated state is a polymer blend consisting of a mixture of two or more types of polymers. However, a combination of a polymer and a monomer may exhibit similar behavior, and such a composition is also included in the polymer blend in the present invention.

As the material used for the recording layer (perpendicular magnetization FF2) of magneto-optical recording, GdFeCo, TbFeC0, etc. can be used.

If the recording layer is made of a metal or the like, or if the substance that can cause a phase change is an inorganic substance such as the metal,
It can be formed on the substrate by vapor deposition, sputtering, or ion blasting on the substrate surface. The recording layer may be a medium layer or a multilayer, but its layer thickness is generally 100-15 mm in terms of optical density required for optical information recording.
00X, preferably 150-100OX
within the range of

In addition, when the recording layer is an organic compound such as a dye or the above-mentioned polymer blend, the substance and, if necessary, a light-absorbing substance are dissolved in an appropriate solvent to prepare a uI+j liquid, and this coating liquid is applied to a spin code. method, roll coat method, etc.? It can be formed on a substrate by applying it to the substrate surface by the Uai method and then drying it.

It is preferable that a tracking guide layer is provided on the recording layer L in order to particularly improve tracking performance during recording. A photographic halogenated emulsion is used as a material for forming the tracking guide layer. Servo marks and the like are formed on the tracking guide layer to perform tracking control.

Further, if desired, an adhesion layer made of a silane coupling agent or the like may be provided in order to improve the adhesion between the recording layer and the storage layer.

On the tracking guide layer or between the recording layer and the tracking guide layer, an inorganic substance such as 5in2, MgF2.5n02 or an organic substance such as UV curable resin is used to physically and chemically protect the recording layer. A protective layer may also be provided.

In addition, silicon dioxide, tin oxide, fluoride, etc. may be added to the substrate side of the recording layer, both sides of the recording layer, or the surface opposite to the substrate in order to improve the scratch resistance, moisture resistance, deformation and deterioration resistance of the recording layer. A thin film of organic materials such as magnesium and zinc sulfide may also be provided.

In addition, on the surface of the recording layer on the substrate side or on the opposite side to the substrate, a light beam made of metals such as An, Cr, and Ni is coated for the purpose of improving the S/N ratio during information reproduction and improving the sensitivity during recording. A reflective layer may also be provided.

Further, the slider used in the optical disk device used in the present invention is a plano-convex lens made of a transparent material and a thin film of a transparent electrode provided on the surface of the convex portion, or a plano-convex lens made of a transparent electrode. be. ”Mizuki Transparent 1
! 1 materials are preferably glass and polymethyl methacrylate, and the thin film of the transparent electrode is 5n02, In
20x and metal or carbon particulate dispersed polymers are preferred.

The pressure applied to the above slider varies depending on the type of electrode of the slider and the material of the surface layer of the information recording medium. In the case of a tracking guide layer formed from an emulsified emulsion, in order to increase the distance between the slider and the information recording medium by Xpm,
It is preferred to maintain a charge within the range of 0 x V/g m.

Next, Examples and Comparative Examples of the present invention will be described. However, the following items do not limit the present invention.

[Example 1] A strip-shaped (web-shaped) polyethylene terephthalate film with a thickness of 75 gm.Secondly, as an undercoat layer, a polyethylene terephthalate film with a thickness of 800
A UV curable resin (3070 Varnish manufactured by IJ-Pond Co., Ltd.) was applied using a roll. A layer of zinc sulfide was formed on the film by electron beam evaporation to a thickness of 700×. Furthermore, a reversible amorphous-ocrystalline phase change is caused by laser irradiation on top of this, and S b 53T e 4 is formed to have a thickness of 700 mm as a recording layer that can be erased and rewritten.
One layer was formed by a dual co-evaporation method. Then, a layer of zinc sulfide was formed on this recording layer by the deuteron beam deposition method to a layer thickness of 1500H.

Next, a silane coupling agent (K
BM-403: Shin-Etsu Chemical [)no1ffi7, H% (
Solvent: Isopropanol) using a roll to 21+jL
Then, a photographic halogenated emulsion (mainly containing gelatin and silver bromide) is applied to the film using a roll to a dry layer thickness of 1 gm, pattern exposure, development and fixing are carried out, followed by servo printing. A tracking guide layer having marks was formed.

The information recording disk film wound into a roll of 11 tons was punched out into a disk shape with an outer diameter of 86 mm and an inner diameter of 25 mm to produce an information recording medium.

Focusing control in Example 1 uses the obtained information recording medium to rotate the information recording medium as shown in the attached FIG. 1. Then, as shown in the attached FIG. 3, a focus error is detected by a four-split photodetector 39, and this detection signal is fed back to a voltage source 33, and a transparent electrode 31 provided on the surface of the slider 32 is connected to an information recording medium. In order to correct the position to the focusing distance, a charge (60 V/μm) converted from the detection signal is applied from the voltage source 33. In this way, the position of the information recording medium was adjusted and focusing control was performed.

[Comparative Example 1] The same information recording as in Example 1 was carried out in the same manner as in Example 1 except that the focus error signal detected by the quarter;:3 photodetector 29 was not fed back to the voltage source 23 in Example 1. Focusing control was performed using a medium.

[Method for Evaluating Focusing Control] A method for evaluating focusing in Example 1 and Comparative Example 1 will be described with reference to the attached FIGS. 1 and 2.

In FIG. 1, a cartridge 13 is manufactured from a transparent material, and an optical head (slider) portion is observed from the top surface of the cartridge 13. 90Orpm information recording medium
If you rotate it and irradiate a monochromatic flash in synchronization with the rotation, interference fringes will appear. By counting the number of interference fringes, the distance between the slider and the information recording medium (recording layer) was measured. By gradually changing the timing of this flash emission from the rotation synchronization signal, it is possible to determine whether or not the above-mentioned distance varies within one revolution, and the amount of variation can be determined by measuring the number of interference fringes.

In addition, since the slider and the information recording medium are in contact with the rotating stationary surface, the rotation speed can be changed from a stationary state to 90 rpm.
By counting the number of interference fringes that pass while raising the slider L, the distance between the slider and the information recording medium can be measured.

Using the L measurement method, determine the amount of variation in the distance between the slider and the information recording medium (recording layer) in the radial direction (range of 20 mm to 40 mm from the center) of each of the above information recording media and the average value of the modulus. Ta.

Regarding the above measurement results, Fig. 4-A shows the variation in the distance between the slider and the information recording medium (recording layer), and Fig. 4-B shows the average value of the distance between the slider and the information recording medium (recording layer). Shown below.

As is clear from Fig. 4-A and Fig. 4-B, the focusing control method used in the present invention (Example 1)
Both the amount of variation and the average value are always constant regardless of whether they are on the inner or outer circumference. In Comparative Example 1 in which feed puncture of the error signal was not performed, both the amount of variation and the average value were large on the inner and outer circumference sides.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing an example of an optical disk device equipped with an information recording medium for explaining the recording or reproducing method of the present invention. FIG. 2-A is a plan view of the optical disk device used in FIG. 1. Figure 2-B is a sectional view taken along the line B-B' of Figure 2-A. Figure 2-C is a cross-sectional view of the second-line diagram with the information recording medium attached.
It is a sectional view taken along the line CC' in figure A. Fig. 2-D shows a state in which the information recording medium is installed.
It is a sectional view taken along the line DD' in figure A. FIG. 3 is an enlarged cross-sectional view of the optical head 11 of FIG. 1 and its surroundings. FIG. 4-A is a graph showing the amount of variation in the distance between the slider and the information recording medium (recording layer) in the radial direction of the information recording medium. :fS4-B is a graph showing the average value of the distance between the slider and the information recording medium (recording layer) in the radial direction of the information recording medium. FIG. 5 is a sectional view showing an example of a conventional drive device for a magneto-optical recording medium. Optical head: ll, 52 Slider: 12.55 Cartridge = 13 Motor = 14 Flexible information recording medium: 15.25.35 Window: 16.
26 Step part = 21 Non-step part: 22 Step bearing part = 23 Air circulation groove = 24 Traveling direction of medium = 25d Air flow = 27.28 Slider = 29 Transparent] JI electrode: 30 Semiconductor laser = 31 Slider: 32 Voltage Source: 33 Collimator lens: 34 Objective lens = 36 Polarizing prism splinter = 37 Cylindrical lens: 38 Quadrant photodetector: 39 Coil = 53 Flexible disk with overlapping magnetized films: 54 Fixed plate: 5
6 Light beam: 59

Claims (1)

[Claims] 1. An optical head having a light emitting part and a light receiving part and having a slider on the top is arranged close to one surface of a rotating flexible information recording medium. , forming a circulating gas layer between the slider and the optical disk, and emitting light from the light emitting part while maintaining the height of the information recording medium substantially constant by maintaining the gap therebetween substantially constant; In a method for recording or reproducing an information recording medium, which includes receiving reflected light from the information recording medium with a light receiving section, a slider having an electrode section is used as the slider, and a slider is used as the slider, and according to the variation in the amount of reflected light. , reads the variation in the distance between the slider and the information recording medium, and applies a positive or negative charge to the electrode of the slider according to the variation in the amount of reflected light to compensate for this variation, thereby recording the information. A method for recording or reproducing an information recording medium, characterized in that the distance between the slider and the information recording medium is maintained constant with high precision by varying the height of the medium.