JP4335220B2 - Magnetic disk formatting device - Google Patents

Description

  The present invention relates to a formatting device that gives magnetic information for servo control to a magnetic disk, and is useful, for example, for preformatting a discrete track magnetic disk.

  As a disk structure type suitable for increasing the recording density of a magnetic disk, a discrete track type is known in which a portion having a small magnetic permeability called a guard band is provided between adjacent recording tracks. In the discrete track type magnetic disk, magnetic interference between adjacent recording tracks is suppressed by the guard band, so that the recording track width and the array pitch can be reduced to increase the recording track density.

  As a prior art document relating to a discrete track type magnetic disk, for example, there is Japanese Patent Application Laid-Open No. 4-310621. Patent Document 1 discloses a structure in which a recording layer made of a magnetic material is partially etched to provide a recess, and a nonmagnetic material serving as a guard band is embedded in the recess, and a recess (void) without embedding the nonmagnetic material. Describes a perpendicular recording magnetic disk structure in which is used as a guard band.

  Similar to the conventional type without a guard band, even in a discrete track type magnetic disk, a disk surface is divided into a user data area and a servo area in such a manner that one round is divided by a predetermined angle, and a plurality of radial lines are arranged. A magnetically readable servo pattern is provided in each servo area. The servo pattern includes a mark for tracking, a mark for clock generation, and address information.

  In the discrete track type magnetic disk, a servo pattern is formed in the servo area in the same manner as the guard band formation in the user data area. That is, the servo pattern is formed by partially removing the magnetic layer in the servo region and embedding or removing only the nonmagnetic material. The servo pattern by such a forming method is composed of a magnetic part and a non-magnetic part. The magnetic part is a remaining part of the magnetic layer, and the non-magnetic part is a part where a non-magnetic material is embedded or a void generated by removing the magnetic layer. A servo pattern composed of a magnetic part and a non-magnetic part can be read as an array pattern with or without magnetism in a state where the magnetization directions of the magnetic parts in the pattern are aligned.

Patent Document 2 (Japanese Patent Application Laid-Open No. 9-138925) is a prior art document related to a magnetic disk format having a servo pattern composed of a magnetic material and a non-magnetic material, that is, magnetic processing for aligning the magnetization direction of the magnetic part in the servo pattern. Gazette). In Patent Document 2, a magnetic field applying operation for moving the magnetic head in the radial direction from the inner circumference to the outer circumference or from the outer circumference to the inner circumference so as to trace one servo area is performed one area at a time for many servo areas. Sequential formatting methods are described. In Patent Document 2, the magnetic head is translated in the case of a magnetic disk having a servo area extending straight in the radial direction, and the arc locus is drawn in the case of a magnetic disk having an arc-shaped servo area. An apparatus for formatting for moving a magnetic head is proposed.
JP-A-4-310621 JP 9-138925 A

  As described above, the format for moving the magnetic head in the radial direction requires less time and the productivity of the magnetic disk compared to the linear recording format in which the magnetic head is moved in the circumferential direction so as to trace the recording track one track at a time. Useful for enhancing.

  However, in the conventional formatting method in which the magnetic head is moved straight in the radial direction of the disk or in a circular arc locus, there is a problem that the area to which the magnetic field is applied by the magnetic head is limited to a band having a certain width. . That is, when the width (circumferential dimension) of the servo area varies depending on the radial position, such as a CAV (constant angular velocity) type magnetic disk, the shape of the area to which the magnetic field is applied by the magnetic head in the format And the shape of the servo area do not match. Unlike a conventional magnetic disk, a magnetic disk in which the position of the servo area is already determined at the stage of formatting like the discrete track type needs to selectively apply a magnetic field to the servo area. If the area to which the magnetic field is applied does not match the servo area, the servo pattern becomes incomplete and the magnetization state of the user data area is disturbed.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a format device capable of correctly giving magnetic information to a predetermined servo area in a disk surface.

  A formatting device for achieving the above object is a formatting device for a magnetic disk in which a plurality of servo areas having a servo pattern composed of a magnetic material and a non-magnetic material are arranged radially, and the magnetic disk is rotated. A motor, a magnetic head having a magnetized portion that is long in one direction, an arm that rotatably supports the magnetic head, and an arrangement of the arm so that the magnetic head moves in a radial direction with respect to the magnetic disk A first actuator that changes the position of the actuator, a second actuator that is attached to the arm and that rotates the magnetic head, and a controller that controls operations of the motor, the magnetic head, the first actuator, and the second actuator. The magnetic disk stops rotating, and one servo area and the magnetic head face each other In this state, the magnetic head is moved in the radial direction while changing the crossing angle between the movement locus of the rotation center of the magnetic head and the longitudinal direction of the magnetized portion, and a magnetic field is applied to the entire servo area. The first operation and the second operation of rotating the magnetic disk so that the other servo area and the magnetic head face each other are repeated until a magnetic field is applied to all the servo areas.

  By rotating the magnetic head in the radial direction with respect to the magnetic disk, the servo area does not protrude from the servo area even if the servo area has a different width (circumferential dimension) depending on the radial position. In addition, a magnetic field for formatting can be applied to the entire servo area so as not to become partial.

  According to the first or second aspect of the present invention, magnetic information can be correctly given to the already determined servo area in the disk surface.

  Hereinafter, an embodiment of the present invention will be described as applied to a format of a discrete track type magnetic disk.

  FIG. 1 is a plan view showing a schematic configuration of a magnetic disk. In the magnetic disk 1 of FIG. 1, the annular disk surface excluding the outer end area 35 and the inner end area 36 has a plurality of user data areas 31 and a plurality of servo areas in such a manner that one round is divided by a predetermined angle. It is divided into 32. The user data area 31 and the servo area 32 are arranged radially and are alternately arranged in the circumferential direction. The user data area 31 is provided with recording tracks 13 at a constant pitch in the radial direction along a concentric circle group, and the servo area 32 is provided with a servo pattern to be described later.

  The configuration of the illustrated magnetic disk 1 is suitable for access (recording / reproducing) in a state of rotating at a constant angular velocity (CAV) and a seek operation by a rotary arm, and the shapes of the user data area 31 and the servo area 32 are as follows. The outer surface of the disk surface expands toward the outer periphery and is curved along the movement path of the tip of the access arm.

In this example, a plurality of magnetically readable marks 18 indicating the circumferential positions of the plurality of servo areas 32 are formed in the outer end area 35 of the magnetic disk 1. The marks 18 have a one-to-one correspondence with the servo areas 32, and the number of marks 18 is the same as the number of servo areas 32. The marks 18 may be formed in the inner end region 36, or the same number of marks 18 as the servo regions 32 may be formed in both the outer end region 35 and the inner end region 36. FIG. 2 is an enlarged view of a portion AA surrounded by a broken line in FIG. 1, and schematically shows configurations of a user data area 31 and a servo area 32.

  The user data area 31 has a recording track 13 made of a magnetic material (white horizontal line portion in the figure) and a guard band 14 made of a non-magnetic material (black horizontal line part in the drawing). In the user data area 31, the recording tracks 13 and the guard bands 14 are alternately arranged in the vertical direction in the figure, and the adjacent recording tracks 13 are magnetically separated by the guard bands 14.

  The servo area 32 has a servo pattern 15. The servo pattern 15 is an arrangement pattern of a magnetic part 16 (white part in the figure) and a non-magnetic part 17 (black part in the figure). The magnetic part 16 is made of a magnetic material made of the same material as the recording track 13, and the non-magnetic part 17 is made of a non-magnetic material made of the same material as the guard band 14.

  FIG. 3 is a cross-sectional view taken along the line aa in FIG. 2 and shows the layer structure of the magnetic disk.

  The magnetic disk 1 includes a substrate 10 as a support, a soft magnetic backing layer 11 for increasing the density of perpendicular recording, and a magnetic recording layer 12 having magnetic anisotropy that can be easily magnetized in the perpendicular direction. The magnetic recording layer 12 is partially filled with a nonmagnetic material, thereby forming a servo pattern 15 and a guard band 14 (not shown in FIG. 3).

  An intermediate layer for matching the crystal structure may be provided between the soft magnetic backing layer 11 and the magnetic recording layer 12, and the magnetic recording layer 12 may be covered with a protective film. 3 illustrates a single-sided configuration in which the magnetic recording layer 12 is disposed on one side of the substrate 10, but a double-sided configuration in which the soft magnetic backing layer 11 and the magnetic recording layer 12 are disposed on both sides of the substrate 10 may be employed.

  In the magnetic disk 1 having the above-described configuration, the magnetic state of the magnetic recording layer 12 that has been formed and has not been subjected to magnetic treatment is an irregular state in which the direction of magnetization differs depending on the part. This state is preferable as the initial state of the user data area 31. However, in order to make the servo pattern 15 magnetically readable in the servo area 32, it is necessary to align the magnetization directions of the magnetic domains in the area. Magnetic processing for aligning the magnetization direction is a format in the magnetic disk 1. The format will be described below.

  FIG. 4 is a block diagram of the formatting device.

  The formatting device 100 supports a spindle motor 110 that rotates the magnetic disk 1 in the direction of the arrow M1, a magnetic head 120 that applies a magnetic field locally to the magnetic disk 1, and supports the magnetic head 120 in a rotatable manner. A possible arm 130, a voice coil motor 140 that is an actuator that rotates the arm 130, and a controller 150 that controls these operations are provided. The controller 150 includes hardware including a processor that executes a program and software including a control program.

  The formatting device 100 applies a magnetic field to the servo area 32 by moving the magnetic head 120 in the radial direction while the rotation of the magnetic disk 1 is stopped and the one servo area 32 and the magnetic head 120 face each other. Thereafter, the magnetic disk 1 is rotated so that the servo area 32 adjacent to the servo area 32 to which the magnetic field is applied and the magnetic head 120 face each other. The application of the magnetic field and the rotation of the magnetic disk 1 are repeated until the magnetic field is applied to all the servo areas 32. The direction of the applied magnetic field is the perpendicular direction of the disk surface.

  By such an operation, a formatted magnetic recording layer 12 having a uniform magnetization direction in the servo area 32 and an irregular magnetization direction in the user data area 31 is obtained.

  In the formatting apparatus 100, the mark 18 of the magnetic disk 1 is used for positioning the magnetic head 120 in the circumferential direction with respect to the magnetic disk 1. That is, the rotation control of the magnetic disk 1 is performed based on the detection signal of the mark 18, thereby causing the magnetic head 120 to face the servo area 32. The mark 18 is detected by a magnetic sensor incorporated in the magnetic head 120.

  FIG. 5 shows how the magnetic head moves.

  As the arm 130 rotates, the magnetic head 120 moves in the radial direction so as to trace one servo area 32. At this time, the magnetic head 120 rotates to match the magnetic field application range with the width of the servo region 32.

  FIG. 6 shows the configuration of the tip of the arm viewed from the disk surface side.

  The arm is assembled with a magnetic head 120 and an actuator 160 that rotates the magnetic head 120. The magnetic head 120 includes an elongated magnetized portion 122 and a mark sensor 124 that magnetically detects the mark 18. The actuator 160 is made of a piezoelectric element, for example. By the operation of the actuator 160, the crossing angle a1 between the movement locus (circular imaginary line) LG of the rotation center G of the magnetic head 120 and the longitudinal direction M5 of the magnetized portion 122 changes. The movement locus LG is a path of the rotation center G when the arm 130 rotates (in this case, an arc), and the crossing angle a1 is strictly an inclination angle in the longitudinal direction M5 with respect to the tangent to the movement locus LG at a certain point in time. is there.

  By rotating the magnetic head 120 in the radial direction with respect to the magnetic disk 1, the servo area 32 does not protrude from the servo area 32 even if the servo area 32 has a shape whose width varies depending on the radial position. A magnetic field for formatting can be applied to the entire servo area so as not to become partial.

  FIG. 7 is a flowchart of format control performed by the controller.

  The controller 150 arranges the magnetic head 120 so that the mark sensor 124 faces the outer end region 35 of the magnetic disk 1 (# 11). That is, the mark 18 can be detected. The magnetic disk 1 is rotated and the output of the mark sensor 124 is monitored. That is, it waits for the mark 18 to arrive at one point (sensor arrangement position) on the rotational movement path of the mark 18 (# 12). When the mark sensor 124 detects the mark 18, the magnetic disk 1 stops rotating (# 13, # 14).

  The magnetic head 120 is moved from the outer circumference side to the inner circumference side so as to trace the servo area 32, and a magnetic field is applied to the servo area 32 (# 15). At this time, the actuator 160 is appropriately driven to rotate the magnetic head 120 so that the circumferential magnetic field application range corresponds to the width of the servo region 32.

  When the application of the magnetic field to one servo area 32, that is, one seek operation is completed, the count value of the set number of seeks (the same number as the number of servo areas) is incremented by one (# 16). The magnetic head 120 is returned from the inner end side to the outer end side (# 17), and the count value is checked (# 18). If the count value has not reached the set value, the process returns to step number # 12. Steps # 12 to # 18 are repeated until the count value reaches the set value.

  When the count value reaches the set value, the magnetic field application to all the servo areas 32 is completed, and the formatting is completed.

  FIG. 8 shows a modification of the mark arrangement on the magnetic disk. Components corresponding to the example of FIG. 1 are given the same reference numerals as in FIG.

The magnetic disk 2 in FIG. 8 is also an annular magnetic disk in which a plurality of servo areas 32 having a servo pattern composed of a magnetic material and a non-magnetic material are arranged radially. In the magnetic disk 2, a plurality of marks 18 indicating the circumferential position of the servo region 32 are formed in the outer end region 35 along the outer peripheral edge, and the periphery of the servo region 32 is also formed in the inner end region 36 along the inner peripheral edge. A plurality of marks 19 indicating the directional positions are formed. The mark 18 in the outer end region 35 is formed at a rate of one for two servo regions 32, and the mark 19 in the inner end region 36 is also formed at a rate of one for two servo regions 32. Has been. However, the servo area 32 corresponding to each mark 18 does not correspond to the mark 19. That is, the mark 18 is disposed in the outer end region 35 on the outer peripheral side for one of the two servo regions 32 adjacent in the circumferential direction, and the mark 19 is disposed in the inner end region 36 on the inner peripheral side for the other. In the format of the magnetic disk 2 shown in FIG. 8, the magnetic sensor 120b having two mark sensors 124 and 125 is used as shown in FIG. The magnetic head is positioned with respect to the servo area 32.

  FIG. 10 is a flowchart showing an example of format control applied to the magnetic disk of FIG.

  The controller 150 arranges the magnetic head 120b at a predetermined position so that either the outer peripheral mark 18 or the inner peripheral mark 19 can be detected. In this example, the outer peripheral mark 18 is first detected (# 21). The magnetic disk 2 is rotated and the output of the mark sensor 124 is monitored. That is, it waits for the mark 18 to arrive at one point (sensor arrangement position) on the rotational movement path of the mark 18 (# 22). When the mark sensor 124 detects the mark 18, the rotation of the magnetic disk 2 is stopped (# 23, # 24).

  The magnetic head 120b is moved from the outer circumference side to the inner circumference side so as to trace the servo area 32, and a magnetic field is applied to the servo area 32 (# 25). At this time, the actuator 160 is appropriately driven to rotate the magnetic head 120 b so that the circumferential magnetic field application range corresponds to the width of the servo region 32.

  When the application of the magnetic field to one servo area 32, that is, one seek operation is completed, the count value of the set number of seeks (the same number as the number of servo areas) is incremented by one (# 26).

  The magnetic disk 2 is rotated and the output of the mark sensor 125 is monitored. That is, it waits for the arrival of the mark 19 at one point (sensor arrangement position) on the rotational movement path of the mark 19 (# 27). When the mark sensor 125 detects the mark 19, the rotation of the magnetic disk 2 is stopped (# 28, # 29).

  The magnetic head 120b is moved from the inner circumference side to the outer circumference side so as to trace the servo area 32, and a magnetic field is applied to the servo area 32 (# 30). Also at this time, the actuator 160 is appropriately driven, and the magnetic head 120 b is rotated so that the circumferential magnetic field application range corresponds to the width of the servo region 32. When the seek operation ends, the count value of the number of seeks is incremented by 1 (# 31), and the count value is checked (# 32). If the count value has not reached the set value, the process returns to step number # 22. Steps # 22 to # 32 are repeated until the count value reaches the set value.

  According to this example, since the magnetic field is applied to the servo area in both the seek operation from the outside to the inside and the seek operation from the inside to the outside, the magnetic field is not applied in the return path of the reciprocal seek operation. The time required for formatting can be shortened. Further, every other mark 18, 19 may be arranged for each of the plurality of servo areas 32 in each of the outer end area 35 and the inner end area 36 of the magnetic disk 2. This makes it possible to increase the mark interval as compared with the case where the marks 18 and 19 are arranged one-on-one in the servo area 32, and it is easy to correctly detect each adjacent mark.

  FIG. 11 shows an example of a method for manufacturing a magnetic disk. An imprint technique can be used for manufacturing the magnetic disk 1. The magnetic disk 2 can also be manufactured in the same procedure as the magnetic disk 1.

  A soft magnetic backing layer 11 and a magnetic layer 12a serving as a magnetic recording layer are sequentially laminated on a glass substrate 6 having a diameter of 63.5 mm (2.5 inches) to obtain a conventional magnetic disk 1a having no guard band. . A Ta film 41 is formed as a metal mask material on the magnetic disk 1a, and a thermoplastic resin 42 is provided to a thickness of about 100 nm. Then, a separately prepared stamper 43 is overlaid on the thermoplastic resin 42 (FIG. 11A).

  The manufacturing procedure of the stamper 43 is as follows. For example, a resist coated on the surface of a silicon plate is patterned by electron beam drawing, and the resulting concavo-convex surface is subjected to a conductive treatment to perform electroplating. In manufacturing the stamper 43, the unevenness 431 corresponding to the mark 18 is formed. For example, an uneven pattern having a size of about several μm square is formed on the outer side of the outermost guard band by 0.3 mm.

  While the thermoplastic resin 42 is heated, the stamper 43 is pressed against the thermoplastic resin 42, and the pattern of the stamper 43 is transferred to the thermoplastic resin 42B [FIG. 11B]. Then, a thin portion (residue) 421 of the thermoplastic resin 42B is etched by, for example, oxygen plasma to partially expose the Ta film 41 [FIG. 11C].

  The Ta film 41 and the magnetic layer 12a are partially removed by Ar etching, for example, using the remaining thermoplastic resin 42C as a mask. As a result, a recording track 13 is formed in the user data area, and a magnetic part of a servo pattern is formed in the servo area (not shown). A mark 18 is also formed [FIG. 11D].

The metal mask 41B which is a part of the Ta film 41 is removed, and then SiO ₂ is deposited on the disk surface having the unevenness by sputtering to fill the unevenness [FIG. 11E].

Finally, excess SiO ₂ is removed by polishing and the surface is flattened to obtain a discrete track type magnetic disk 1 having a guard band 14 (FIG. 11F). Formatting is performed by the above-described formatting apparatus 100 on the magnetic disk 1 thus manufactured.

  12 and 13 show other examples of the mark sensor.

  In FIG. 12, a concave portion is formed as a mark 18b indicating the circumferential position of the servo area 32 in the magnetic disk 1b. In this case, a capacitance sensor or an optical sensor can be used as the mark sensor 126. The mark sensor 126 may be attached to the magnetic head 120c for formatting as shown, or may be fixed at a predetermined position.

  In FIG. 13, the mark sensor 127 includes a laser light source 271, a mirror 272, a beam splitter 273, and a photodetector 274, and optically detects the mark 18.

  Light emitted from the laser light source 271 passes through the beam splitter 273 and enters the mirror 272. The mirror 272 is fixed at a position facing the outer end region of the magnetic disk 1 and guides light from the laser light source 271 to the surface of the magnetic disk 1. Reflected light having an intensity corresponding to the reflectance of the surface of the magnetic disk 1 is sequentially reflected by the mirror 272 and the beam splitter 274 and enters the photodetector 274. The mark 18 can be detected by setting the reflectance of the mark 18 to be larger or smaller than the surrounding reflectance. The mirror 272 may be attached to the magnetic head 120.

  In the above embodiment, the shape of the servo region 32 is not limited to the example. For example, when seeking on a translational arm is assumed, the fan shape is formed by straight lines and arcs. Further, it is not always necessary to continue in the radial direction from the inner periphery to the outer periphery of the annular region in which the recording track group is arranged.

  The shape, number, and arrangement position of the marks 18 and 19 are not limited to the examples. The magnetic disk manufacturing method may be a method in which the magnetic layer is partially etched using a resist patterned by electron beam drawing as a mask, and a nonmagnetic material is embedded in the etched portion.

  INDUSTRIAL APPLICABILITY The present invention is useful for preformatting that is a format at the manufacturing stage of a magnetic disk in which a magnetic recording layer is composed of a magnetic material and a nonmagnetic material, such as a discrete track type and a discrete bit type. The present invention contributes to an improvement in the productivity of high recording density magnetic disks.

It is a top view which shows schematic structure of a magnetic disc. It is a figure which shows typically the structure of a user data area | region and a servo area | region. It is a figure which shows the layer structure of a magnetic disc. It is a block diagram of a formatting device. It is a top view which shows the mode of the movement of a magnetic head. It is a schematic diagram which shows the structure of the front-end | tip part of the arm seen from the disc surface side. It is a flowchart of the format control which a controller performs. It is a top view which shows the modification of the mark arrangement | positioning in a magnetic disc. It is a figure which shows the modification of a magnetic head. 10 is a flowchart showing an example of format control applied to the magnetic disk of FIG. It is a figure which shows an example of the manufacturing method of a magnetic disc. It is a figure which shows the other example of a mark sensor. It is a figure which shows the other example of a mark sensor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Format device 1, 2 Magnetic disk 32 Servo area 15 Servo pattern 16 Magnetic part 17 Nonmagnetic part 110 Spindle motor 120 Magnetic head 122 Magnetization part 130 Arm 140 Voice coil motor (1st actuator)
160 Actuator (second actuator)
150 Controller G Magnetic head rotation center LG Movement locus a1 Crossing angle

Claims (2)

A format device for a magnetic disk in which a plurality of servo areas having a servo pattern composed of a magnetic material and a non-magnetic material are arranged radially,
A motor for rotating the magnetic disk;
A magnetic head having a long magnetized portion in one direction;
An arm that rotatably supports the magnetic head;
A first actuator that changes the arrangement of the arms so that the magnetic head moves in a radial direction with respect to the magnetic disk;
A second actuator attached to the arm for rotating the magnetic head;
A controller for controlling operations of the motor, the magnetic head, the first actuator, and the second actuator;
While the rotation of the magnetic disk is stopped and one servo area and the magnetic head face each other, the crossing angle between the movement locus of the rotation center of the magnetic head and the longitudinal direction of the magnetized portion is changed. A first operation of moving the magnetic head in the radial direction to apply a magnetic field to the entire servo region, and a second operation of rotating the magnetic disk so that the other servo region and the magnetic head face each other. A format device for a magnetic disk, characterized by repeating until a magnetic field is applied to all servo areas. The formatting device for a magnetic disk according to claim 1, wherein the arm and the first actuator constitute a rotary head moving mechanism that moves the magnetic head so as to draw an arcuate locus.