JPH09251637A - Information recording medium and information recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an information recording medium having high accuracy in the shape by forming a projecting part provided along the circumferential direction at least on the outer peripheral part corresponding to a projecting part formed along the radial direction. SOLUTION: A data zone consisting of the recessed and projection parts and a servo zone are radially formed respectively on a substrate of a magnetic disk 3, and further an anchor zone is formed on the outermost circumference, then magnetic films are formed on these surfaces. That is, the data zone is concentric and formed so that the data tracks DT thereon are in the projected state. Servo patterns SP are formed in the servo zone. On the anchor zone, an annular anchor pattern AP concentric with the tracks DT is formed to be the projected part. Since the anchor zone, in which the direction of pattern on the recessed and projection part is the circumferential direction, is thus provided outside the servo pattern, the contraction of a molded substance in the radial direction on the servo zone is controlled by the anchor zone in the case the substrate of the magnetic disk 3 is constituted with a synthetic resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording medium for recording and reproducing information such as data and programs by utilizing magnetism and light, and an information recording apparatus provided with the information recording medium.

[0002]

2. Description of the Related Art For example, in a computer system, a hard disk device, a magneto-optical disk device or the like is used as an information recording device. In recent years, in order to realize a compact hard disk device having a large recording capacity, the applicant has proposed a hard disk device incorporating a magnetic disk as an information recording medium as described below (Japanese Patent Laid-Open No. 6-259709). See the bulletin).

FIG. 8 is a plan view showing an example of the magnetic disk, FIG. 9 (A) is a sectional view in the radial direction, and FIG. 9 (B).
[FIG. 3] is a cross-sectional structural view in the circumferential direction. This magnetic disk 30
Substrate 31 made of synthetic resin, glass, aluminum, etc.
In this area, a data recording area (data zone) and a control signal recording area (servo zone) each formed of an uneven portion are radially formed, and a magnetic film 32 is formed on the surface thereof.
That is, in the data zone, concentric circular data tracks DT for recording data and the like are formed as convex portions, and guard bands GB for separating adjacent data tracks DT are concave portions. Is formed. Further, in the servo zone, servos such as gray code for specifying the data track DT, a clock mark serving as a reference for generating a servo clock, and a wobbled mark for tracking control of the magnetic head are provided. A pattern SP is formed. This servo pattern SP may be formed by a convex portion or a concave portion.

At least one of the gray code, the clock mark, and the wobbled mark is formed along the rotation trajectory of the magnetic head, and is obtained by reproducing the gray code, the clock mark, or the wobbled mark. The operation of recording / reproducing data or the like by the magnetic head is controlled in accordance with the received signal. Also, the magnetic head measures the amount of change corresponding to the eccentricity of the magnetic disk from the signal obtained by reproducing the gray code, clock mark or wobbled mark, and in accordance with the measurement result, data by the magnetic head, etc. The recording / reproducing operation of is controlled.

According to the magnetic disk 30 having such a structure, since the guard band GB is formed as a physical concave portion with respect to the data track DT, the guard band G is formed.
The possibility that data or the like is reproduced from B is reduced. Therefore, in order to reduce the crosstalk, the guard band GB
Since it is not necessary to increase the width of the track, the track pitch can be reduced to increase the recording capacity.

When the substrate 31 of the magnetic disk 30 having such a structure is made of synthetic resin, a stamper having a negative pattern in which the concavo-convex portion is inverted is formed on the surface is made of nickel or the like and used as a mold. Set and pour the molten synthetic resin along the negative pattern of the stamper. Then, the solidified molded article of the synthetic resin is peeled off from the stamper, so that the substrate 31 on the surface of which the irregularities are formed.
Is being made.

[0007]

When the substrate 31 of the magnetic disk 30 described above is made of synthetic resin, as shown in FIG. 10, the temperature of the sub-mirror surface die 47 on which the stamper 46 is mounted is set to the temperature of the substrate 31. It is adjusted to be lower than the glass transition temperature of the constituent synthetic resin. For example, when the glass transition temperature of the synthetic resin is 140 ° C, the temperature of the lower mirror surface mold 47 is 13
It is adjusted to 0 ° C. The stamper 46 is placed on the under-mirror surface mold 47, and is held until the temperature of the stamper 46 becomes the same as the temperature of the under-mirror surface mold 47.

After that, when the synthetic resin melted at, for example, 320 ° C. to 350 ° C. is injected, the synthetic resin is cooled to about the same temperature as the stamper 46 while being in contact with the stamper 46 and solidified. Into a molded product 31a. The molded product 31a and the stamper 46 contract with this cooling and solidification, but the thermal expansion coefficient (for example, 7e-5 / deg to 12e-5 / deg) of the synthetic resin forming the molded product 31a is nickel that constitutes the stamper 46. Coefficient of thermal expansion (for example, 12.8
e-6 / deg), the shrinkage amount of the molded product 31a after cooling and solidification is larger than the shrinkage amount of the stamper 46. The molded product 31a in such a state is peeled off from the stamper 46 to form the substrate 31, but the uneven portion formed on the surface of the molded product 31a becomes a problem here.

As shown in FIG. 11, the uneven portion is concentric in the data zone and radial in the servo zone. Therefore, in the data zone, since the pattern direction of the uneven portion is the circumferential direction, the radial contraction of the molded product 31a is suppressed. However, in the servo zone, since the pattern direction of the concavo-convex portion is substantially radial, the radial contraction of the molded product 31a easily occurs. Therefore, a large gap is formed between the center side edge of the convex portion of the servo zone formed on the surface of the molded article 31a and the center side edge of the concave portion formed on the stamper 46 corresponding to this convex portion. Stress is generated.

When the molded product 31a in such a state is peeled off from the stamper 46, the stress thereof causes the edge of the convex portion of the servo zone formed on the surface of the molded product 31a on the center side, particularly near the outer periphery away from the center. There is a problem in that the edge of 1 may be broken as shown in FIG.
For example, FIG. 13 is a diagram showing an example of measuring the shape of the convex portion of the servo zone formed on the surface of the molded article 31a. In this way, the edge on the center side of the convex portion is broken and the axial height 2
The protrusion 31b of 4 nm is generated.

In view of the above points, an object of the present invention is to provide an information recording medium having a high shape accuracy and an information recording apparatus provided with the information recording medium.

[0012]

According to the present invention, there is provided an information recording medium having a surface on which intermittent projections along the radial direction are formed, at least the projections along the radial direction. This is achieved by forming a convex portion along the circumferential direction on the outer peripheral portion corresponding to the formation portion of.

According to the above-mentioned structure, the stress of the intermittent convex portions along the radial direction generated at the time of producing the information recording medium covers the portion where the intermittent convex portions along the radial direction are formed. It can be relaxed by the formed convex portion along the circumferential direction. Therefore, it is possible to prevent the intermittent breakage of the convex portion along the radial direction and improve the shape accuracy.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. The embodiments described below are preferred specific examples of the present invention, and therefore, various technically preferable limitations are added. However, the scope of the present invention is not limited to the following description. It is not limited to these forms unless otherwise stated.

FIG. 1 is a perspective view showing a configuration example of a hard disk device which is an embodiment of the information recording apparatus of the present invention. In the hard disk drive 1, a spindle motor 9 is disposed on the back side of a plane portion of a housing 2 formed of an aluminum alloy or the like, and a magnetic disk 3 rotated at a constant angular velocity by the spindle motor 9 is provided.
Is provided. Further, the housing 2 includes an arm 4
Is swingably mounted around the vertical axis 4a.
A voice coil 5 is attached to one end of the arm 4, and a head slider 6 is attached to the other end of the arm 4. Magnets 7a and 7b are mounted on the housing 2 so as to sandwich the voice coil 5. A voice coil motor 7 is formed by the voice coil 5 and the magnets 7a and 7b.

In such a configuration, the voice coil 5
When an electric current is supplied from the outside to the arm 4, the arm 4 rotates around the vertical axis 4a based on the force generated by the magnetic fields of the magnets 7a and 7b and the electric current flowing through the voice coil 5. Thereby, the head slider 6 attached to the other end of the arm 4 moves substantially in the radial direction of the magnetic disk 3. Therefore, the magnetic head 8 mounted on the head slider 6 performs a seek operation on the magnetic disk 3 to record and reproduce data on a predetermined data track of the magnetic disk 3.

FIG. 2 is a plan view showing a magnetic disk which is the first embodiment of the information recording medium of the present invention, and FIG. 3 is a partially enlarged perspective view thereof. A data recording area (data zone) and a control signal recording area (servo zone), which are uneven portions, are radially formed on the substrate 31 made of synthetic resin, glass, aluminum or the like of the magnetic disk 3, and the anchor zone is further formed. Is formed on the outermost periphery, and the magnetic film 32 is formed on the surface thereof. That is, in the data zone, concentric circular data tracks DT for recording data and the like are formed as convex portions, and a guard band GB for partitioning adjacent data tracks DT is formed.
Are formed to be concave portions. Further, in the servo zone, servo patterns SP such as a gray code for specifying the data track DT, a clock mark serving as a reference when generating a servo clock, and a wobbled mark for tracking control of the magnetic head are formed. ing. This servo pattern SP may be formed by a convex portion or a concave portion. An annular anchor pattern AP, which is concentric with the data track DT, is formed in the anchor zone so as to form a convex portion.

The above-mentioned magnetic disk 3 can be manufactured by utilizing the optical technique, and its manufacturing method will be described with reference to FIGS.
Will be described. First, the surface of the glass master 41 is coated with, for example, a photoresist 42. The glass master 41 coated with the photoresist 42 is mounted on a turntable 43 and rotated. For example, only a portion of the photoresist 42 which forms a concave portion is irradiated with a laser beam 44 to perform pattern cutting. After irradiating the laser beam 44, the photoresist 42 is developed to form a photoresist 4
The exposed portion 2 is removed. The surface of the glass master 41 from which the exposed portions of the photoresist 42 have been removed is plated with nickel 45. The nickel 45 is transferred to the glass master 4
The stamper 46 is peeled off from the stamper 1.

Next, the stamper 46 is set in a mold provided with a mirror lower mold 47 and a mirror upper mold 48 which are opposed to each other. That is, the stamper 46 is placed on the under-mirror surface mold 47 and pressed by the outer peripheral ring 49, and the over-mirror surface mold 48 is closed to hold the temperature of the stamper 46 until the temperature of the under-mirror surface mold 47 becomes the same temperature. . Then, the molten synthetic resin is injected into the mold, and the synthetic resin is cooled to a temperature substantially the same as the temperature of the stamper 46 and solidified to form the molded product 3a. The molded product 3a is taken out of the mold to form a substrate 31, and a magnetic film 32 is formed on the surface of the substrate 31 by sputtering or the like to form the magnetic disk 3. Then, the magnetic disk 3 is set in the magnetizing device 50 and magnetized by the magnetizing magnetic head 51.

According to the magnetic disk 3 having such a structure, the anchor zone having the pattern direction of the concavo-convex portion in the circumferential direction is provided outside the servo zone in which the pattern direction of the concavo-convex portion is substantially radial direction. Therefore, when the substrate 31 of the magnetic disk 3 is made of synthetic resin, radial contraction of the molded product 3a in the servo zone is suppressed by the anchor zone. Therefore, there is a large gap between the center side edge of the convex portion of the servo zone formed on the surface of the molded product 3a and the center side edge of the concave portion formed in the stamper 46 corresponding to this convex portion. No stress is generated.

The molded product 3a in such a state is stamper 4
Even if it is peeled off from 6, the edge on the center side of the convex portion of the servo zone formed on the surface of the molded product 3a, especially the edge near the outer periphery away from the center is not destroyed. For example, in FIG.
FIG. 6 is a diagram showing an example of measuring the shape of the convex portion of the servo zone formed on the surface of the molded product 3a. In this way, the edge on the center side of the convex portion is not destroyed, and the convex portion with high accuracy is Has been formed. Therefore, when the head slider 6 floats,
It is possible to eliminate the collision between the protrusion 31b and the magnetic head 8 which has occurred conventionally, and it is possible to improve the accuracy of signal recording and reproduction.

FIG. 7 is a partially enlarged perspective view of a magnetic disk which is a second embodiment of the information recording medium of the present invention.
This magnetic disk 3 has substantially the same structure as that of the magnetic disk 3 shown in FIG. 3, but the anchor pattern AP is formed in the anchor zone only in the servo zone. That is, this anchor pattern AP is
It is not formed in the data zone portion and has a shape in which an annular pattern concentric with the data track DT is divided.

Even in the magnetic disk 3 having such a structure, an anchor zone having a pattern direction of the concavo-convex portion is provided outside the servo zone in which the pattern direction of the concavo-convex portion is substantially radial direction. Therefore, when the substrate 31 of the magnetic disk 3 is made of synthetic resin, radial contraction of the molded product 3a in the servo zone is suppressed by the anchor zone. Therefore, there is a large gap between the center side edge of the convex portion of the servo zone formed on the surface of the molded product 3a and the center side edge of the concave portion formed in the stamper 46 corresponding to this convex portion. No stress is generated. Therefore, even if the molded product 3a in such a state is peeled off from the stamper 46, the edge on the center side of the convex portion of the servo zone formed on the surface of the molded product 3a, especially the edge near the outer periphery away from the center is destroyed. It will not be done.

In each of the above-described embodiments, the anchor pattern AP is provided in only one row, but the invention is not particularly limited to this, and an arbitrary number of rows of anchor patterns AP may be provided. Further, although the magnetic disk is used as the information recording medium and the hard disk device is used as the information recording device, the information recording medium is not limited to this. For example, the information recording medium is an optical disk such as a CD or a magneto-optical disk such as an MO or MD, The information recording device can be applied to an optical disk device and a magneto-optical disk device.

[0025]

As described above, according to the present invention,
Since it is possible to reduce the occurrence of shape defects, it is possible to significantly reduce the manufacturing cost.

[Brief description of drawings]

FIG. 1 is a perspective view showing a configuration example of a hard disk device that is an embodiment of an information recording device of the present invention.

FIG. 2 is a plan view showing a magnetic disk which is the first embodiment of the information recording medium of the present invention.

3 is a partially enlarged perspective view of the magnetic disk shown in FIG.

FIG. 4 is a first diagram illustrating a method for manufacturing the magnetic disk shown in FIG. 2;

FIG. 5 is a second diagram illustrating the method for manufacturing the magnetic disk shown in FIG. 2;

FIG. 6 is a diagram showing an example of shape measurement of the magnetic disk shown in FIG.

FIG. 7 is a partially enlarged perspective view of a magnetic disk which is a second embodiment of the information recording medium of the present invention.

FIG. 8 is a plan view showing an example of a magnetic disk which is a conventional information recording medium.

9 is a sectional side view of the magnetic disk shown in FIG.

FIG. 10 is a diagram for explaining a problem of the magnetic disk shown in FIG.

11 is a partially enlarged perspective view of the magnetic disk shown in FIG.

12 is an enlarged cross-sectional side view showing a problem of the magnetic disk shown in FIG.

13 is a diagram showing an example of measuring the shape of the magnetic disk shown in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Hard disk device, 2 ... Housing, 3, 30
... Magnetic disks, 3a, 31a ... Molded products, 4.
..Arms, 4a ... Vertical axis, 5 ... Voice coil, 6 ... Head slider, 6a ... Rail, 6b
... Rail, 6c ... Tapered part, 6d ... Tapered part, 7 ... Voice coil motor, 7a ... Magnet, 7b ... Magnet, 8 ... Magnetic head, 9 ...
..Motor, 10 ... Control unit, 11 ... Clock signal generation unit, 12 ... Tracking servo unit, 13 ...
・ Playback unit, 14 ... Recording unit, 31 ... Substrate, 32 ...
..Magnetic film, 41 ... glass master, 42 ... photoresist, 43 ... turntable, 44 ... laser light, 45 ... nickel, 46 ... stamper, 47
・ ・ ・ Mirror surface mold, 48 ・ ・ ・ Mirror surface mold, 49 ・ ・ ・
Outer ring, 50 ... Magnetizing device, 51 ... Magnetic head for magnetizing, AP ... Anchor pattern

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location // G11B 7/007 9464-5D G11B 7/007

Claims (4)

[Claims] 1. An information recording medium having a surface on which intermittent projections along the radial direction are formed, wherein at least the outer peripheral portion corresponding to the formation portion of the projections along the radial direction has a circumferential direction. An information recording medium characterized in that a convex portion is formed along it. 2. The information recording medium according to claim 1, wherein the convex portion along the circumferential direction is formed over the entire outermost circumference. 3. An information recording apparatus for recording / reproducing information on an information recording medium having a surface on which intermittent projections are formed along the radial direction, wherein at least a portion corresponding to the projections along the radial direction is formed. An information recording apparatus characterized in that a convex portion along the circumferential direction is formed on an outer peripheral portion of the information recording apparatus. 4. The information recording apparatus according to claim 3, wherein the convex portion along the circumferential direction is formed over the entire outermost circumference.