JP3646990B2 - Master information magnetic recording apparatus and method of manufacturing magnetic recording medium - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a master information magnetic recording apparatus and a master information carrier for pre-recording a predetermined information signal using a master information carrier on a magnetic recording medium used in a magnetic recording / reproducing apparatus having a large capacity and a high recording density. The present invention relates to a method of manufacturing a magnetic recording medium used.
[0002]
[Prior art]
In order to realize a small-sized and large-capacity magnetic recording / reproducing apparatus, it is increasingly required to increase the recording density. In a hard disk drive which is a typical magnetic recording / reproducing apparatus, an apparatus having a surface recording density exceeding 1 Gbit / in 2 (1.55 Mbit / mm 2) has already been commercialized, and after several years, a surface recording density of 10 Gbit / As the in 2 (15.5 Mbit / mm 2) device is expected to be put into practical use, rapid technological progress is recognized.
[0003]
The technological background that made it possible to achieve such high recording density is the emergence of new signal processing methods such as improved media performance, head / disk interface performance, and partial response. It has greatly contributed to increasing the recording density. However, in recent years, the trend of increasing track density has greatly exceeded the trend of increasing linear recording density. This is due to the practical application of a magnetoresistive element type head, which has much better reproduction output performance than conventional induction type magnetic heads. Currently, by using a magnetoresistive element type head, a signal recorded with a track width of only a few μm can be reproduced with a good S / N ratio. With further improvement in head performance, the track pitch is expected to reach the submicron range in the near future.
[0004]
The head tracking servo technology plays an important role in order for the head to accurately scan such a narrow track and reproduce the signal with a good S / N ratio. Details of such tracking servo technology are disclosed in, for example, Journal of Japan Society of Applied Magnetics, Vol. 20, No. 3, p. 771 (1996), Yamaguchi, “High-precision servo technology for magnetic disk drives”. Has been. According to this document, the current hard disk drive is provided with an area where tracking servo signals, address information signals, reproduction clock signals, etc. are recorded at regular angular intervals in one round of the disk, that is, at an angle of 360 degrees. ing. Recording such information signals in advance is called preformat recording. The magnetic head reproduces these signals at regular intervals, thereby confirming the position of the head and accurately scanning the track while correcting as necessary.
[0005]
The tracking servo signal, the address information signal, the reproduction clock signal, and the like described above are reference signals for the head to accurately scan the track, and therefore high head positioning accuracy is required for recording. For example, according to the content described in the 93rd meeting of the Japan Society of Applied Magnetics, 93-5, p. 35 (1996), Uematsu et al. In a hard disk drive, after the disk is incorporated in the drive, preformat recording is performed while strictly controlling the position of the magnetic head using a dedicated servo recording device.
[0006]
Preformat recording of such servo signals, address information signals, reproduction clock signals, etc., is also possible for removable hard disk media to which a large-capacity flexible disk or disk cartridge which has been commercialized in recent years can be attached and removed. It is done using.
[0007]
Preformat recording by a magnetic head using such a dedicated servo recording device has the following problems.
[0008]
First, since the recording by the magnetic head is basically linear recording by relative movement between the head and the medium, the above-described method for recording while strictly controlling the position of the magnetic head using a dedicated servo recording device is used. Therefore, a lot of time is required for preformat recording. Furthermore, a dedicated servo recording device is quite expensive. Therefore, the cost required for preformat recording increases.
[0009]
This problem becomes more serious as the track density of the magnetic recording apparatus is improved. In addition to the increase in the number of tracks in the disk radial direction, the time required for preformat recording becomes longer due to the following reasons. In other words, the higher the track density, the higher the accuracy required for head positioning. Therefore, it is necessary to reduce the angular interval in which a servo area for recording an information signal such as a tracking servo signal is provided in one round of the disk. For this reason, the higher the recording density, the greater the amount of signal to be preformatted on the disc, which requires more time.
[0010]
Further, although magnetic disk media tend to be reduced in diameter, there is still a great demand for large diameter disks of 3.5 inches and 5 inches. The larger the recording area of the disc, the greater the amount of signal to be preformatted. The time required for preformat recording has a great influence on the cost performance of such a large-diameter disk.
[0011]
The second problem in conventional preformat recording is that the recording magnetic field spreads due to the spacing between the head and the medium, and the tip pole shape of the recording head. That is, it lacks steepness.
[0012]
Since recording by a magnetic head is basically dynamic linear recording by relative movement between the head and the medium, a certain amount of head-medium spacing must be provided from the viewpoint of the interface performance between the head and the medium. Absent. Also, current magnetic heads usually have two elements that handle recording and reproduction separately, so that the leading edge side pole width of the recording gap corresponds to the recording track width, and the trailing edge side pole width is several times the recording track width. More than that.
[0013]
The above two points both cause the recording magnetic field to spread at the end of the recording track, and as a result, the magnetization transition at the end of the preformat-recorded track lacks steepness, or the erase areas on both sides of the track end Result. In the current tracking servo technology, the head position is detected based on the amount of change in reproduction output when the head scans off the track. Therefore, not only is the signal-to-noise ratio excellent when the head scans the track accurately as in the case of reproducing the data signal recorded between the servo areas, but also the reproduction output when the head scans off the track. The change amount, that is, the off-track characteristic is required to be steep. Therefore, if the magnetization transition at the track end portion prerecorded as described above lacks steepness, it becomes difficult to realize an accurate tracking servo technique in future submicron track recording.
[0014]
Various techniques have already been proposed for solving the two problems in preformat recording by the magnetic head as described above.
[0015]
For example, Japanese Patent Laid-Open No. 63-183623 discloses a copying technique such as a tracking servo signal using a magnetic transfer technique as a solution to the first problem. It is a fact that the productivity at the time of preformat recording can be improved by using this magnetic transfer technology. However, this magnetic transfer technology is effective for a magnetic disk medium having a relatively low coercive force and a small areal recording density, such as a flexible disk. It cannot be used for a high coercive force medium having a resolution for recording density.
[0016]
In the magnetic transfer technique, in order to ensure transfer efficiency, it is necessary to apply an AC bias magnetic field having an amplitude of about 1.5 times the coercivity of the transferred disk. Since the master information recorded on the master disk is a magnetization pattern, in order to prevent the master information from being demagnetized by this AC bias magnetic field, the coercive force of the master disk is about three times or more of the coercivity of the transferred disk. It is required to be. The coercive force of the current high-density hard disk medium is 1500 to 2500 oersted to bear a high surface recording density. Furthermore, this value is expected to reach 3000 to 4000 Oersted in order to bear the future surface recording density on the order of 10 gigabits. That is, the master disk is required to have a coercive force of 4500 to 7500 oersted in the present state and 9000 to 12000 oersted in the future.
[0017]
Realizing such a coercive force in the master disk is difficult from the viewpoint of selection of a magnetic material. Furthermore, with current magnetic recording technology, master information cannot be recorded on a master disk having such a high coercive force. Therefore, in the magnetic transfer technology, the coercive force value that can be realized in the master disk is inevitably limited by the coercive force of the transfer target disk.
[0018]
Also, for example, in JP-A-7-153060, a disk medium substrate having a concavo-convex shape corresponding to a tracking servo signal, an address information signal, a reproduction clock signal, etc. is formed by a stamper, and a magnetic layer is formed on the substrate. A pre-embossed disk technology to form is disclosed. This technique is an effective solution to both of the above two problems. However, it is expected that the uneven shape of the disk surface will affect the flying characteristics of the head during recording and playback (or the contact state with the medium in the case of contact recording), resulting in problems with the head / medium interface performance. Is done. Further, since the substrate manufactured by the stamper is basically a plastic substrate, the substrate cannot be heated at the time of forming the magnetic layer necessary for ensuring the medium performance, and the necessary medium SN ratio cannot be ensured. is there.
[0019]
As described above, the technique described in Japanese Patent Application Laid-Open No. 63-183623 or Japanese Patent Application Laid-Open No. 7-153060 has other important issues such as medium SN ratio, interface performance, etc. At the expense of performance, it is not a truly effective solution.
[0020]
Another preformat recording technique is described in the specification of Japanese Patent Application No. 8-191889. In this recording technique, the surface of the master information carrier is formed with a concavo-convex shape corresponding to an information signal on the surface of the substrate, and at least the surface of the concavo-convex shape is formed of a ferromagnetic material. The magnetic pattern corresponding to the irregular shape on the surface of the master information carrier is recorded on the magnetic recording medium.
[0021]
As the ferromagnetic material for forming the convex surface of the master information carrier, a soft magnetic film having a high saturation magnetic flux density, or a hard or semi-hard magnetic film having an in-plane coercive force of 40 kA / m or less is preferably used. More preferably, when the surface of the master information carrier is brought into contact with the surface of the magnetic recording medium, the direct current magnetic field for exciting the ferromagnetic material forming the convex surface of the master information carrier or the recording of the magnetization pattern is assisted. Apply an AC bias magnetic field. As a result, the above-described problems relating to the technique described in Japanese Patent Laid-Open No. 63-183623 or Japanese Patent Laid-Open No. 7-153060 can be solved.
[0022]
The recording technique described in the specification of the above Japanese Patent Application No. 8-191889 is a problem in preformat recording by a magnetic head using a conventional dedicated servo recording device, or Japanese Patent Application Laid-Open No. 63-183623 or Regarding the problems of the technique disclosed in Japanese Patent Application Laid-Open No. 7-153060, it has the following characteristics.
[0023]
In the recording technique described in the specification of Japanese Patent Application No. 8-191889, the recording magnetic field generated by the ferromagnetic material of the convex portion on the surface of the master information carrier magnetized in one direction corresponds to the uneven shape of the master information carrier. The magnetized pattern is recorded on the magnetic recording medium. That is, by forming an uneven shape corresponding to a tracking servo signal, address information signal, reproduction clock signal, etc. on the surface of the master information carrier, preformat recording of these information signals can be performed on a magnetic recording medium.
[0024]
In this recording technique, recording is performed by a leakage magnetic field generated from the ferromagnetic material of the convex portion due to a change in magnetoresistance due to the uneven shape. Therefore, the recording mechanism is basically the same as the recording using the conventional magnetic head that performs recording by the leakage magnetic field generated from the recording gap of the magnetic head. However, while the recording by the conventional magnetic head is the dynamic linear recording by the relative movement between the head and the medium, the recording by the above configuration is a static surface recording without the relative movement between the master information carrier and the medium. It can be said that. Due to such characteristics, the recording technique described in the specification of Japanese Patent Application No. 8-191889 provides the following effective solution to the above-mentioned problems related to preformat recording.
[0025]
First, since this recording technique is surface recording, the time required for preformat recording is very short compared to recording by a conventional magnetic head. Further, an expensive servo recording apparatus for performing recording while strictly controlling the position of the magnetic head is not required. Therefore, productivity related to preformat recording can be greatly improved and production cost can be reduced.
[0026]
Secondly, since this recording technique is a static recording that does not involve relative movement between the master information carrier and the medium, the master information carrier surface and the magnetic recording medium surface are brought into close contact with each other during recording. Pacing can be minimized. Furthermore, the recording magnetic field does not spread due to the pole shape of the recording head, unlike the recording by the magnetic head. For this reason, the magnetization transition at the track end portion where the preformat recording has been performed has a steepness superior to the recording by the conventional magnetic head. As a result, more accurate tracking is possible.
[0027]
The recording technique described in the specification of Japanese Patent Application No. 8-191889 is the magnetic transfer technique disclosed in Japanese Patent Laid-Open No. 63-183623 and the pre-embossed technique disclosed in Japanese Patent Laid-Open No. 7-153060. It does not cause the problems described for disk technology. That is, there is no restriction on the configuration and magnetic characteristics of the magnetic recording medium on which preformat recording is performed.
[0028]
For example, in the magnetic transfer technique disclosed in Japanese Patent Application Laid-Open No. 63-183623, a master disk having master information recorded by a magnetization pattern is a magnetic recording medium itself, and therefore has a corresponding magnetic recording medium resolution. I need. For this reason, the magnetic flux density and film thickness of the master disk magnetic layer cannot be sufficiently increased, and the magnitude of the generated transfer magnetic field becomes very small. Further, since the master information is recorded by the magnetization pattern, demagnetization occurs due to the butt magnetization of the dibit, and the transfer magnetic field gradient in the magnetization transition region is also gentle. In order to ensure sufficient transfer efficiency even with such a weak transfer magnetic field, in the magnetic transfer technique, it is necessary to apply an AC bias magnetic field having an amplitude of about 1.5 times the coercivity of the transferred disk. As a result, as described above, the coercive force of the transfer target disk is limited, and can only be used for a flexible disk having a relatively low recording density.
[0029]
On the other hand, the master information carrier described in the specification of Japanese Patent Application No. 8-191889 has the master information as a concavo-convex pattern, and the convex portion is caused by the change in magnetoresistance due to the concavo-convex shape. Recording is performed by a leakage magnetic field generated from a ferromagnetic material, which is similar to recording by a magnetic head. Since the resolution as a magnetic recording medium is not required unlike the master disk in the magnetic transfer technology, the magnetic flux density and volume of the ferromagnetic material forming the convex surface of the master information carrier should be increased to the same level as the conventional magnetic head. Thus, a large recording magnetic field equivalent to that of the magnetic head can be generated. As a result, it is possible to exhibit sufficient recording capability for all magnetic recording media, from ordinary flexible disks, hard disks, and high coercivity media that will be responsible for future gigabit recording.
[0030]
In addition, the pre-embossed disc technology disclosed in Japanese Patent Application Laid-Open No. 7-153060 is restricted by the substrate material and shape of the disc medium to be preformatted as described above, so that the substrate temperature at the time of film formation of the medium is limited. The head-medium interface performance was sacrificed in relation to the medium S / N ratio performance and the head flying characteristics (contact state with the medium in the case of contact recording). In contrast, the recording technique described in the specification of Japanese Patent Application No. 8-191889 is not subject to any restrictions on the substrate material or surface shape of the magnetic recording medium to be preformatted as described above.
[0031]
[Problems to be solved by the invention]
As described above, the recording technique described in the specification of Japanese Patent Application No. 8-191889 can perform static surface recording regardless of the configuration and magnetic characteristics of the magnetic recording medium to be preformatted. The present invention provides a technique, and is an excellent technique capable of efficiently performing good preformat recording without sacrificing other important performance such as medium SN ratio and interface performance.
[0032]
However, in order to make this recording technique truly effective, it is necessary to realize uniform adhesion between the master information carrier and the magnetic recording medium. If uniform adhesion is not realized between the two, sufficient recording signal intensity cannot be obtained due to spacing loss, and therefore there is a possibility that a good SN ratio cannot be ensured. Furthermore, due to the spread of the recording magnetic field, the magnetization transition at the track end lacks steepness and there is a possibility that sufficient off-track characteristics cannot be obtained.
[0033]
Accordingly, the present invention provides a technique for statically recording information on a recording medium using a master information carrier having master information as a concavo-convex shape pattern, in which the magnetic recording medium is uniformly adhered to the master information carrier, and reliable. It is an object of the present invention to provide a means capable of performing highly preformat recording.
[0034]
[Means for Solving the Problems]
  In the master information magnetic recording apparatus according to the present invention, a region made of a ferromagnetic thin film and having a concavo-convex pattern corresponding to an information signal formed on a surface of a substrate and a region where the concavo-convex pattern is not formed are predetermined. An apparatus for recording information signals of the master information carrier on a magnetic recording medium having a ferromagnetic layer using master information carriers arranged alternately at an angular interval ofThe
[0035]
  AndA first master information magnetic recording apparatus according to the present invention.StructureThe formation is performed using a master information carrier in which a through hole is provided in at least a part of a region where the uneven pattern is not formed.Configured as beforeWith the master information carrier and the magnetic recording medium in contact with each other, the through hole of the master information carrier is formed.As an exhaust passageBy exhausting the gas existing between the master information carrier and the magnetic recording medium, the concave-convex pattern of the master information carrier and the magnetic recording medium are brought into close contact with each other.A magnetic field for applying a magnetic field for exciting a ferromagnetic thin film formed on a convex surface of the master information carrier; and a means for aligning the master information carrier with the magnetic recording medium. Application meansIt is characterized by that.
[0036]
  The second of the master information magnetic recording apparatus according to the present invention.StructureUsing a master information carrier in which the surface height of at least a part of the region where the uneven pattern is not formed is lower than the surface height of the region where the uneven pattern is formedConfigured as beforeIn a state where the master information carrier and the magnetic recording medium are in contact with each other, the area between the master information carrier where the irregular shape is not formed and the magnetic recording mediumBetween the master information carrier and the magnetic recording medium using an air gap as an exhaust passage.By exhausting the gas present in the magnetic recording medium, the concave and convex pattern of the master information carrier and the magnetic recording medium are brought into close contact with each other.Applying a magnetic field for exciting a ferromagnetic thin film formed on a convex surface of the master information carrier, and a means for aligning the master information carrier with the magnetic recording medium. Magnetic field applying meansIt is characterized by that.
[0037]
By using the master information magnetic recording apparatus as described above, the magnetic recording medium can be uniformly adhered to the master information carrier, and highly reliable preformat recording can be performed.
[0038]
Preferably, the contact means includes a pair of flanges for sandwiching the master information carrier and the magnetic recording medium, and means for fastening the peripheral portions of the pair of flanges to each other. The close contact means by the exhaust also includes the mechanical fastening means, whereby a more uniform close contact between the master information carrier and the magnetic recording medium can be obtained. In other words, the master information is usually obtained by mechanically tightening the peripheral portion so as to compensate for the attractive force (atmospheric pressure) that tends to concentrate on the central portion of the master information carrier and the magnetic recording medium by the exhaust duct provided in the central portion. Warpage of the carrier and the magnetic recording medium is suppressed, and both are in close contact with each other. Further, an elastic member is interposed between at least one of the pair of flanges and the master information carrier and the magnetic recording medium, so that the master information carrier and the magnetic recording medium are more closely adhered to each other.
[0039]
In addition, it is preferable that a marker is disposed on the master information carrier as means for aligning the master information carrier with the magnetic recording medium.
[0040]
  The method of manufacturing a magnetic recording medium according to the present invention includes a region formed of a ferromagnetic thin film on a surface of a substrate and having a concavo-convex pattern corresponding to an information signal, and a region where the concavo-convex pattern is not formed. A method of recording information signals of the master information carrier on a magnetic recording medium having a ferromagnetic layer using master information carriers alternately arranged at predetermined angular intervals.The
[0041]
  And1st of the manufacturing method of the magnetic-recording medium by this inventionStructureThe composition uses a master information carrier provided with a through hole in at least a part of the region where the uneven pattern is not formed,An alignment step of aligning the master information carrier and the magnetic recording medium;With the master information carrier in contact with the magnetic recording body, the through hole of the master information carrier is formed.As an exhaust passageThe gas existing between the master information carrier and the magnetic recording medium is exhausted.And a magnetic field applying step of applying a magnetic field for exciting the ferromagnetic thin film of the master information carrier.It is characterized by that.
[0042]
  2nd of the manufacturing method of the magnetic-recording medium by this inventionStructureThe composition uses a master information carrier in which the surface height of at least a part of the region where the concavo-convex pattern is not formed is lower than the surface height of the region where the concavo-convex pattern is formed,An alignment step of aligning the master information carrier and the magnetic recording medium;In a state where the master information carrier and the magnetic recording medium are in contact with each other, the area between the master information carrier where the uneven pattern is not formed and the magnetic recording mediumBetween the master information carrier and the magnetic recording medium using an air gap as an exhaust passage.Exhausting the gas present inA step of closely contacting the concave-convex pattern of the master information carrier and the magnetic recording medium, and a magnetic field applying step of applying a magnetic field for exciting the ferromagnetic thin film of the master information carrier.It is characterized by that.
[0043]
According to the method for manufacturing a magnetic recording medium as described above, the magnetic recording medium can be uniformly adhered to the master information carrier, and highly reliable preformat recording can be performed.
[0044]
In the contact step, it is preferable that the master information carrier and the magnetic recording medium are sandwiched between a pair of flanges and the peripheral portions of the pair of flanges are fastened together. In addition to the close contact by the exhaust, the mechanical information is also tightened to obtain a more uniform close contact between the master information carrier and the magnetic recording medium.
[0045]
Further, in the alignment step, it is preferable that alignment between the master information carrier and the magnetic recording medium is performed using a marker disposed on the master information carrier.
[0046]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to FIGS.
[0047]
(Embodiment 1)
FIG. 3 is a sectional view showing a first embodiment of an apparatus according to the invention for recording an information signal formed on a master information carrier on a magnetic recording medium. In the figure, 31a and 31b are master information carriers, 32 is a hard disk, 33 is an upper flange, 34 is a lower flange, 35a and 35b are permanent magnets, 36a and 36b are exhaust devices, 37a and 37b are three-way valves, and 30 is an O-ring. It is. The magnetization directions of the permanent magnets 15a and 15b are directions from the back of the paper to the front.
[0048]
On the surfaces of the master information carriers 31a and 31b, for example, as shown in FIG. 1, regions 12 in which fine concavo-convex shapes corresponding to information signals are formed are provided at predetermined angular intervals. FIG. 2 shows an enlarged part of this region 12 (region A in FIG. 1). The tracking servo signal, clock signal, and address information signal areas are sequentially arranged in the track length direction. In FIG. 2, the hatched portion is a convex portion, and the surface of the convex portion is formed of a ferromagnetic material such as Co.
[0049]
A method of forming a fine uneven shape corresponding to such an information signal on the surface of the master information carrier will be described below. First, a ferromagnetic thin film made of Co or the like is formed on a glass substrate surface with fine surface roughness and good flatness by sputtering. Next, for example, the resist film is exposed and developed using a lithography technique using a laser beam or an electron beam such as a photolithography method, and then an uneven shape is formed by dry etching or the like. Alternatively, after forming and patterning a resist film on the surface of the substrate, an uneven shape is formed by a so-called lift-off method in which a ferromagnetic thin film made of Co or the like is formed and the resist film is removed.
[0050]
Note that the method for forming the uneven shape is not limited thereto, and the fine uneven shape may be directly processed using, for example, a laser, an electron beam, an ion beam, or by machining. The method for forming the ferromagnetic thin film on the glass substrate is not limited to the sputtering method, and a conventional thin film forming method such as a vacuum deposition method, an ion plating method, a CVD method, or a plating method is used. be able to.
[0051]
The level difference between the convex and concave surface and the bottom surface of the concave corresponding to the information signal depends on the surface property of the magnetic recording medium on which the master information is recorded and the bit size of the master information. 05 μm or more, preferably 0.1 μm or more. In one embodiment, it was 0.5 μm.
[0052]
The ferromagnetic thin film material that forms the uneven surface is not limited to Co. Many kinds of magnetic materials can be used regardless of hard magnetic material, semi-hard magnetic material, and soft magnetic material. In order to generate a sufficient recording magnetic field regardless of the type of magnetic recording medium on which master information is recorded, it is better that the saturation magnetic flux density of the magnetic material is larger. Particularly for a high coercivity magnetic disk exceeding 2000 Oersted and a flexible disk having a large magnetic layer thickness, sufficient recording may not be performed when the saturation magnetic flux density is 0.8 Tesla or less. A magnetic material having a saturation magnetic flux density of 0.8 Tesla or higher, preferably 1.0 Tesla or higher is used.
[0053]
As shown in FIG. 1, a through-hole 13 is provided in a region other than the region 12 where the uneven shape corresponding to the information signal of the master information carrier 11 is formed. When the substrate of the master information carrier is glass, the through hole 13 can be formed using a known processing method such as ultrasonic processing, laser processing, or wet etching. It is preferable that the diameter of the through hole is as small as possible and the number of through holes is as large as possible. In one example, through holes having a diameter of 1 mm were formed at a ratio of 3 mm square by ultrasonic processing.
[0054]
When the information signal formed on the master information carrier is recorded on the hard disk as a magnetic recording medium, it is necessary to bring the center of the master information pattern into close contact with the center of the hard disk. In order to facilitate this alignment, a marker 14 is formed on the inner periphery of the master information carrier 11 as shown in FIG. The marker 14 is formed simultaneously with the concavo-convex shape corresponding to the information signal. The marker 14 formed on the inner periphery of the master information carrier 11 is formed so as to align the inner periphery of the hard disk. However, the marker 14 is formed on the outer periphery of the master information carrier 11 so as to align the outer periphery of the hard disk. Markers may be formed.
[0055]
In the present embodiment, the procedure for recording the information signal formed on the master information carrier on the hard disk as a magnetic recording medium will be described with reference to FIGS. In the present embodiment, the master information carriers 31a and 31b and the hard disk 32 are brought into close contact with each other using atmospheric pressure. By exhausting the air existing between the master information carriers 31a, 31b and the hard disk 32 through the through holes 39 provided in the master information carriers 31a, 31b, the hard disk 32 is pressed against the master information carriers 31a, 31b. The convex surface of the concavo-convex pattern formed on the information carriers 31a and 31b and the hard disk 32 are in close contact with each other. Thereafter, the permanent magnets 35a and 35b are used to magnetize the ferromagnetic thin film on the convex surface of the concave / convex pattern formed on the master information carriers 31a and 31b, whereby an information signal corresponding to the concave / convex shape is transferred to the hard disk 32. Record. The procedure is described in detail below.
[0056]
First, as shown in FIG. 5, the hard disk 32 is magnetized in advance in the direction of the arrow 51 along the circumferential direction using a permanent magnet 52. An electromagnet may be used instead of the permanent magnet. Next, as shown in FIG. 3, the O-ring 30 is mounted in the groove of the lower flange 34, and the master information carrier 31b and the hard disk 32 are stacked thereon. At this time, since the marker (14 in FIG. 1) for aligning the center of the master information pattern and the center of the hard disk 32 is provided on the master information carrier 31b as described above, this marker is aligned with the inner periphery of the hard disk 32. . Further, a master information carrier 31a and an upper flange 33 having an O-ring 30 mounted in the groove are overlaid on the hard disk 32. At this time, the marker provided on the inner periphery of the master information carrier 31a is aligned with the inner periphery of the hard disk 32 in the same manner as described above.
[0057]
The upper three-way valve 37a is operated to suck air between the upper flange 33 and the master information carrier 31a by the exhaust device 36a. The lower three-way valve 37b is switched so that the space between the lower flange 34 and the master information carrier 31b becomes atmospheric pressure. When the air between the master information carrier 31a and the hard disk 32 is exhausted through a through hole 39 provided in the master information carrier 31a, the hard disk 32 is pressed against the master information carrier 31a, and the two are in close contact with each other. Next, as shown in FIG. 4A, a DC exciting magnetic field 41a is applied by turning the permanent magnet 35a parallel to the upper flange and centering on the exhaust duct 38a. By this operation, the ferromagnetic thin film on the convex surface of the concave / convex pattern formed on the master information carrier 31a is magnetized, and an information signal corresponding to the concave / convex shape is recorded on the hard disk 32. As described above, the hard disk 32 is initially magnetized in advance along the circumferential direction using a permanent magnet or the like, and this initial magnetization direction and the direction of the magnetic field applied by the permanent magnet 35a when recording an information signal. May be the same or opposite. In one embodiment, the direction is reversed.
[0058]
Next, the lower three-way valve 37b is operated to suck air between the lower flange 34 and the master information carrier 31b by the exhaust device 36b. The upper three-way valve 37a is switched so that the space between the upper flange 33 and the master information carrier 31a becomes atmospheric pressure. When the air between the master information carrier 31b and the hard disk 32 is exhausted through the through-hole 39 provided in the master information carrier 31b, the hard disk 32 is pressed against the master information carrier 31b, and both are in close contact with each other.
[0059]
As shown in FIG. 4B, a DC excitation magnetic field 41b is applied by turning the permanent magnet 35b parallel to the lower flange 34 and centering on the exhaust duct 38b. By this operation, the ferromagnetic thin film on the convex surface of the concave / convex pattern formed on the master information carrier 31b is magnetized, and an information signal corresponding to the concave / convex shape is recorded on the hard disk 32. In one embodiment, the initial magnetization direction of the hard disk 32 and the direction of the magnetic field applied by the permanent magnet 35b when recording an information signal are reversed.
[0060]
With the above procedure, preformat recording can be performed on both surfaces of the hard disk 32 in a short time. Instead of using a permanent magnet to magnetize the ferromagnetic thin film on the convex surface of the concave-convex pattern formed on the master information carrier, an electromagnet may be used. Further, since the ferromagnetic thin film on the surface of the master information carrier is magnetized with the upper flange 33 or the lower flange 34 interposed between the permanent magnet and the master information carrier, the upper flange 33 and the lower flange 34 The material is preferably a non-magnetic material such as brass steel.
[0061]
In this embodiment, when the magnetic recording medium is not a hard disk but a flexible disk, if the through hole provided in the master information carrier is large, the flexible disk is sucked into the through hole and deformed, and preformat recording is performed at an accurate location. Or a signal to be recorded will be lost. Therefore, as described above, it is preferable that the size of the through hole is as small as possible and that as many through holes as possible are provided. By doing so, it is possible to perform highly reliable preformat recording not only on the hard disk but also on a flexible disk. Further, in this embodiment, since the master information carrier is disposed on both sides of the magnetic recording medium, preformat recording can be efficiently performed on both sides of the magnetic recording medium in a short time, which can contribute to improvement of productivity.
[0062]
(Embodiment 2)
FIG. 7 is a cross-sectional view showing a second embodiment of the device according to the invention for recording an information signal formed on a master information carrier on a magnetic recording medium. In the figure, 71 is a master information carrier, 72 is a hard disk, 73 is an upper flange, 74 is a lower flange, 75 is a permanent magnet, and 70 is an elastic plate. Further, 76 is an exhaust device, 77 is a three-way valve, 78 is an exhaust duct, and 79 is a bolt for fixing the upper flange 73 and the lower flange 74.
[0063]
On the surface of the master information carrier 71, for example, as shown in FIG. 6A, regions 62 in which fine irregularities corresponding to information signals are formed are provided at predetermined angular intervals. A specific example of the information signal recorded in this area is shown in FIG. 2 as in the first embodiment. As described in the first embodiment, such a concavo-convex shape is obtained by forming a ferromagnetic thin film made of Co or the like on the surface of a glass substrate with fine surface roughness and good flatness by sputtering, for example, photo The resist film is exposed and developed using a lithography technique using a laser beam or an electron beam such as a lithography method, and then formed by dry etching or the like.
[0064]
As shown in FIG. 6, in this embodiment, the surface height of the region 62 and the outer peripheral portion (white blank portion in FIG. 6A) where the irregular shape corresponding to the information signal of the master information carrier 61 is formed. In comparison, the surface height of the other region 63 (the hatched portion in FIG. 6A) is lowered. Hereinafter, this region 63 is referred to as a recessed region. FIG. 6B shows a cross section taken along the one-dot chain line AA in the circumferential direction in FIG. On the region 62, for example, an uneven shape corresponding to an information signal as shown in FIG. 2 is formed. After this uneven shape is formed as described above, the recessed region 63 is formed using a known processing method such as machining, ultrasonic processing, or laser processing. The level difference between the concave / convex region 62 and the concave region 63 is several tens of μm or more, preferably 100 μm or more, depending on the thickness of the substrate of the master information carrier 61.
[0065]
When an information signal formed on the master information carrier 61 is recorded on a hard disk, which is a magnetic recording medium, the center of the master information pattern needs to be brought into close contact with the center of the hard disk. Similar to the first embodiment, a marker 64 as shown in FIG. 6 is formed on the inner periphery of the master information carrier 61 of the present embodiment, thereby aligning the inner periphery of the hard disk. Also in this case, the marker formation position is not limited to the inner periphery of the master information carrier 61, and the marker may be formed on the outer periphery of the master information carrier 61 so as to align the outer periphery of the hard disk.
[0066]
In the present embodiment, the procedure for recording the information signal formed on the master information carrier on the hard disk as a magnetic recording medium will be described with reference to FIGS. In this embodiment, the hard disk 72 is uniformly brought into close contact with the hard disk 72 by using the atmospheric pressure, and the area where the irregular shape corresponding to the information signal of the master information carrier 71 is formed, and the master information carrier 71 and the hard disk 72 are mechanically connected. Pressure contact. By setting the surface height of the recessed area where the uneven shape corresponding to the information signal is not formed lower than the surface height of the area where the uneven shape is formed, between the master information carrier 71 and the hard disk 72. There is a void in By exhausting the air in the gap, the hard disk 72 is brought into intimate contact with the region where the irregular shape corresponding to the information signal of the master information carrier 71 is formed. Thereafter, by using the permanent magnet 75 to magnetize the ferromagnetic thin film on the convex surface of the concave / convex pattern formed on the master information carrier, an information signal corresponding to the concave / convex shape is recorded on the hard disk 72. The procedure is described in detail below.
[0067]
First, as shown in FIG. 5, the hard disk 72 is previously magnetized in the direction of the arrow 51 along the circumferential direction using the permanent magnet 52. Next, as shown in FIG. 7, the elastic plate 70, the hard disk 72, and the master information carrier 71 are sequentially stacked on the lower flange 74. A through hole having the same size as the hard disk 72 is formed in the center of the elastic plate 70. When the master information carrier 71 is overlaid on the hard disk 72, the aforementioned marker (64 in FIG. 6) is aligned with the inner periphery of the hard disk 72. Finally, the elastic plate 70 and the upper flange 73 are overlaid on the master information carrier 71. Various materials having elasticity such as silicon rubber can be used for the elastic plate 70.
[0068]
The three-way valve 77 is operated to exhaust the air between the hard disk 72 and the concave region where the concave and convex shape corresponding to the information signal of the master information carrier 71 is not formed by the exhaust device 76. As a result, the hard disk 72 is brought into close contact with the region where the irregular shape corresponding to the information signal is formed. In the present embodiment, since the exhaust duct 78 is arranged at the center of the apparatus, the exhaust conductance at the center of the master information carrier 71 is large. Accordingly, the negative pressure due to the exhaust from the central hole of the hard disk 72 greatly acts on the central part of the master information carrier 71, but does not act so strongly on the outer peripheral part. As a result, the outer peripheral part of the master information carrier 71 and the hard disk There is a possibility that the adhesion of will deteriorate.
[0069]
Therefore, in the present embodiment, elastic plates 70 are provided between the upper flange 73 and the master information carrier 71 and between the lower flange 74 and the hard disk 72, respectively, and the upper flange 73 and the lower flange 74 are connected to the bolt 79. Is connected. Then, by adjusting the tightening torque of the bolt 79, the master information carrier 71 and the hard disk 72 are appropriately pressed. In this manner, the hard disk 72 is in intimate contact with the area where the concavo-convex shape corresponding to the information signal of the master information carrier 71 is formed.
[0070]
Finally, as shown in FIG. 8, a DC excitation magnetic field 81 is applied by rotating the permanent magnet 75 in parallel with the upper flange 73 and along the circumferential direction. By this operation, the ferromagnetic thin film on the convex-concave surface corresponding to the information signal formed on the master information carrier 71 is magnetized, and the information signal corresponding to the concave-convex shape is recorded on the hard disk 72. As described above, the hard disk 72 is initially magnetized in the circumferential direction using a permanent magnet or the like in advance. The initial magnetization direction and the direction of the magnetic field applied by the permanent magnet 75 when recording an information signal are as follows. It may be the same or vice versa. In one embodiment, the direction is reversed. As described in the first embodiment, since the ferromagnetic thin film on the surface of the master information carrier is magnetized with the upper flange 73 interposed between the permanent magnet and the master information carrier, the upper flange The material 73 is preferably a nonmagnetic material such as brass steel.
[0071]
As described above, in this embodiment, by making the surface height of the region where the uneven shape corresponding to the information signal of the master information carrier is not formed lower than the surface height of the region where the uneven shape is formed, Create a gap between the master information carrier and the hard disk. And the area | region where the uneven | corrugated shape is formed is closely_contact | adhered with a hard disk by exhausting the air of this space | gap. Furthermore, by providing means for mechanically pressing the master information carrier and the hard disk, preformat recording with higher reliability is possible.
[0072]
【The invention's effect】
According to the master information magnetic recording apparatus of the present invention, by having means for aligning the master information carrier and the magnetic recording medium, and means for closely contacting, the master information carrier and the magnetic recording medium are uniformly adhered, Reliable preformat recording can be realized.
[0073]
Further, by using a master information carrier provided with a through hole in at least a part of a region where the uneven shape is not formed, and exhausting air existing between the master information carrier and the magnetic recording medium from the through hole, Alternatively, a master information carrier in which the surface height of at least a part of the region where the uneven shape is not formed is lower than the surface height of the region where the uneven shape is formed, and the region where the uneven shape is not formed and the magnetic recording medium By exhausting the gas existing between the two, the effect of bringing the master information carrier and the magnetic recording medium into uniform contact with each other can be further enhanced, and more reliable preformat recording can be realized.
[Brief description of the drawings]
FIG. 1 is a plan view schematically showing the structure of a master information carrier according to a first embodiment of the invention.
FIG. 2 is an enlarged view of part A in FIG. 1, showing an example of an uneven pattern corresponding to an information signal formed on the surface of a master information carrier;
FIG. 3 is a diagram showing the configuration of a master information magnetic recording apparatus for recording the information signal of the master information carrier of FIG. 1 on a magnetic recording medium.
4 is a diagram showing a method for recording an information signal of a master information carrier on a magnetic recording medium using the master information magnetic recording apparatus of FIG. 3;
FIG. 5 is a diagram showing an example of a method for initial magnetization of a magnetic recording medium in advance.
FIG. 6 is a diagram schematically showing a planar structure and a sectional structure of a master information carrier according to a second embodiment of the present invention.
7 is a diagram showing the configuration of a master information magnetic recording apparatus that records information on the master information carrier of FIG. 6 on a magnetic recording medium.
8 is a view showing a method for recording an information signal of a master information carrier on a magnetic recording medium using the master information magnetic recording apparatus of FIG. 7;
[Explanation of symbols]
11, 31a, 31b, 61, 71 Master information carrier
12 62 Region in which concave and convex shapes corresponding to information signals are formed
13,39 Through hole
14,64 Hard disk inner circumference alignment marker
32, 72 hard disks
33, 73 Upper flange
34, 74 Lower flange
35a, 35b, 75 Permanent magnet
36a, 36b, 76 Exhaust device
37a, 37b, 77 Three-way valve
38a, 38b, 78 Exhaust duct
30 O-ring
41a, 41b, 81 DC exciting magnetic field
63 Recessed area
70 Elastic plate
79 volts

Claims (9)

A master made of a ferromagnetic thin film on the surface of a substrate, and a region in which a concavo-convex pattern corresponding to an information signal is formed and a region in which the concavo-convex pattern is not formed are alternately arranged at predetermined angular intervals A master information magnetic recording apparatus for recording an information signal of the master information carrier on a magnetic recording medium having a ferromagnetic layer using an information carrier,
Wherein at least a portion in the through hole of the uneven pattern is not formed region is configured so that using a master information carrier provided,
While in contact with the front SL master information carrier and the magnetic recording medium, by evacuating the gas existing between the master information carrier and the magnetic recording medium through hole as an exhaust passage of the master information carrier A contact means configured to bring the concave-convex pattern of the master information carrier into close contact with the magnetic recording medium ;
Means for aligning the master information carrier with the magnetic recording medium;
A master information magnetic recording apparatus comprising: a magnetic field applying unit that applies a magnetic field for exciting a ferromagnetic thin film formed on a convex surface of the master information carrier . A master made of a ferromagnetic thin film on the surface of a substrate, and a region in which a concavo-convex pattern corresponding to an information signal is formed and a region in which the concavo-convex pattern is not formed are alternately arranged at predetermined angular intervals A master information magnetic recording apparatus for recording an information signal of the master information carrier on a magnetic recording medium having a ferromagnetic layer using an information carrier,
Is configured so that using a master information carrier that is lower than the surface height of the concavo-convex at least a portion surface height of the shape pattern is not formed region the uneven pattern formed region,
Before Symbol kept in contact with the master information carrier and the magnetic recording medium, and the master information carrier a gap between the master information carrier area that irregularities are not formed between said magnetic recording medium as an exhaust passage A contact means configured to bring the concave / convex pattern of the master information carrier into close contact with the magnetic recording medium by exhausting a gas existing between the magnetic recording medium and the magnetic recording medium ;
Means for aligning the master information carrier with the magnetic recording medium;
A master information magnetic recording apparatus comprising: a magnetic field applying unit that applies a magnetic field for exciting a ferromagnetic thin film formed on a convex surface of the master information carrier . 3. The master information magnetic recording according to claim 1, wherein the contact means includes a pair of flanges for sandwiching the master information carrier and the magnetic recording medium, and means for fastening the peripheral portions of the pair of flanges to each other. apparatus. 4. The master information magnetic recording apparatus according to claim 3 , further comprising an elastic member interposed between at least one of the pair of flanges and the master information carrier and the magnetic recording medium. 3. The master information magnetic recording apparatus according to claim 1, wherein a marker is arranged on the master information carrier as means for aligning the master information carrier with the magnetic recording medium. A master made of a ferromagnetic thin film on the surface of a substrate, and a region in which a concavo-convex pattern corresponding to an information signal is formed and a region in which the concavo-convex pattern is not formed are alternately arranged at predetermined angular intervals A method of manufacturing a magnetic recording medium using an information carrier to record an information signal of the master information carrier on a magnetic recording medium having a ferromagnetic layer,
Using a master information carrier provided with a through hole in at least a part of the region where the uneven pattern is not formed,
An alignment step of aligning the master information carrier and the magnetic recording medium;
While in contact with the front SL master information carrier and the magnetic recording medium, by evacuating the gas existing between the master information carrier and the magnetic recording medium through hole as an exhaust passage of the master information carrier An adhesion process for closely attaching the concave-convex pattern of the master information carrier and the magnetic recording medium;
Method of manufacturing a magnetic recording medium having a magnetic field application step of applying a magnetic field for exciting the ferromagnetic film of the master information carrier. A master made of a ferromagnetic thin film on the surface of a substrate, and a region in which a concavo-convex pattern corresponding to an information signal is formed and a region in which the concavo-convex pattern is not formed are alternately arranged at predetermined angular intervals A method of manufacturing a magnetic recording medium using an information carrier to record an information signal of the master information carrier on a magnetic recording medium having a ferromagnetic layer,
Using a master information carrier in which the surface height of at least a part of the region where the uneven pattern is not formed is lower than the surface height of the region where the uneven pattern is formed,
An alignment step of aligning the master information carrier and the magnetic recording medium;
While in contact with the front SL master information carrier and the magnetic recording medium, the master information carrier a gap between the master information carrier uneven pattern is not formed region between said magnetic recording medium as an exhaust passage A step of closely contacting the magnetic recording medium with the concavo-convex shape pattern of the master information carrier by exhausting the gas existing between the magnetic recording medium and the magnetic recording medium;
And a magnetic field applying step of applying a magnetic field for exciting the ferromagnetic thin film of the master information carrier . The magnetic recording medium manufacturing according to claim 6 or 7 , wherein, in the adhesion step, the master information carrier and the magnetic recording medium are sandwiched between a pair of flanges, and peripheral portions of the pair of flanges are fastened to each other. Method. 8. The magnetic recording medium according to claim 6 , wherein in the alignment step, alignment of the master information carrier and the magnetic recording medium is performed using a marker disposed on the master information carrier. 9. Production method.

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