Disc device and reference pattern writing method thereof

Abstract

Provided is a disk device excellent in reliability, capable of writing a plurality of reference patterns to a disk at appropriate intervals without intersecting each other, and a reference pattern writing method thereof. Deviation of a writing position of a spiral pattern is detected, a prescribed speed is successively corrected in a direction in which the deviation disappears, and each spiral pattern is written based on the corrected prescribed speed.

Description

[0001] This application enjoys priority based on Japanese Patent Application No. 2022-142376 (filed on September 7, 2022). This application incorporates the entire contents of that basic application by reference. Technical Field

[0002] Embodiments of the present invention relate to a disk device and a method for writing a reference pattern thereto. Background Technology

[0003] In a disk device that has a disk and read / write heads for writing / reading data to that disk, a process is performed to write multiple reference patterns in the shape of curves to a disk that has no records, which will become the reference for the servo pattern writing process to the disk, also known as SSW (Self Servo Write).

[0004] Multiple reference patterns are written to the disk in a spiral pattern from the inner to the outer periphery while the disk is being rotated, with predetermined intervals between them. These reference patterns are called spiral patterns, and a set of these spiral patterns is called a multi-spiral pattern or spiral sector group.

[0005] The spacing between the spiral patterns written to the disk can become unstable due to external forces transmitted to the actuators supporting the read / write head, the flexible circuit board (EPC), and other components. In the worst case, multiple spiral patterns may even intersect each other. If this happens, servo pattern writing processing cannot be performed. Summary of the Invention

[0006] Embodiments of the present invention provide a highly reliable disk device and a method for writing reference patterns to a disk at appropriate intervals that do not overlap.

[0007] The disk device according to an embodiment of the present invention includes: a read / write head having a write element for writing data to a rotatable disk and a plurality of read elements for reading data from the disk, and freely movable in the radial direction of the disk; and a controller for controlling the rotation of the disk and the movement of the read / write head. The controller includes: a first control unit that moves the read / write head radially along the disk at a predetermined speed while writing a first reference pattern, which serves as a reference for a predetermined process on the disk, to the disk using a write element; a second control unit that moves the read / write head radially along the disk at the predetermined speed such that the first reference pattern written by the first control unit is tracked using each of the read elements; a detection unit that detects a deviation between the trajectory of the read / write head moved by the second control unit and the first reference pattern written by the first control unit using read signals from each of the read elements; a correction unit that corrects the predetermined speed in a direction that makes the deviation detected by the detection unit disappear; and a third control unit that moves the read / write head radially along the disk at the predetermined speed corrected by the correction unit while writing a second reference pattern, which serves as a reference for the predetermined process, to the disk using a write element at a predetermined interval from the first reference pattern.

[0008] Furthermore, the reference pattern writing method according to an embodiment of the present invention includes: in a disk device having a write element for writing data to a rotatable disk and a plurality of read elements for reading data from the disk and a magnetic head that moves freely in the radial direction of the disk, and a controller for controlling the rotation of the disk and the movement of the magnetic head, the magnetic head is moved radially along the disk at a predetermined speed while the write element writes a first reference pattern to the disk as a reference for a predetermined process of the disk; the magnetic head is moved radially along the disk at the predetermined speed such that the written first reference pattern is tracked by each of the read elements; a deviation between the trajectory of the magnetic head moving to track the first reference pattern and the written first reference pattern is detected by the read signal of each of the read elements; the predetermined speed is corrected in a direction that makes the detected deviation disappear; while the magnetic head is moved radially along the disk at the corrected predetermined speed, the write element writes a second reference pattern to the disk as a reference for the predetermined process at a predetermined interval from the first reference pattern. Attached Figure Description

[0009] Figure 1 This is a diagram illustrating the structure of each embodiment.

[0010] Figure 2 This is a graph showing the movement speed of the magnetic head in each embodiment.

[0011] Figure 3 This is a flowchart illustrating the control process of the first embodiment.

[0012] Figure 4 This is a diagram illustrating the case where the writing element writes the first spiral pattern in each embodiment.

[0013] Figure 5 This is a diagram illustrating how each reading element in each embodiment tracks the first spiral pattern.

[0014] Figure 6 It is a diagram showing the changes in the corresponding positions of a spiral pattern and each reading element in each embodiment, as well as the waveforms of the output signals of each reading element corresponding to the corresponding positions.

[0015] Figure 7 This is a diagram showing the correspondence between the writing positions of each spiral pattern in each embodiment.

[0016] Figure 8 This is a diagram showing the state after the first to Nth spiral patterns in each embodiment have been written.

[0017] Figure 9 This diagram is shown with reference to the correspondence of the writing positions of previous spiral patterns.

[0018] Figure 10 This is a flowchart illustrating the control process of the second embodiment.

[0019] Explanation of reference numerals in the attached figures

[0020] 1…disk, 3…actuator, 10…head, 11…write element, 12a…read element (first read element), 12b…read element (second read element), 20…controller, 30…speed gauge. Detailed Implementation

[0021] Hereinafter, various embodiments will be described with reference to the accompanying drawings. Furthermore, common structures in the embodiments will be labeled with the same reference numerals, and repeated descriptions will be omitted. Additionally, the drawings are schematic diagrams intended to facilitate the implementation and understanding of the embodiments; their shapes, dimensions, proportions, etc., may differ from actual devices, and appropriate design modifications can be made with reference to the following description and known techniques.

[0022] (First Embodiment)

[0023] The disk device of the first embodiment is in Figure 1 As shown in the image.

[0024] The center of the disc-shaped disk 1 is mounted on the rotating shaft of the spindle motor (SPM) 2, and the disk 1 is rotated in the direction of the arrow shown in the figure by the power of the spindle motor (SPM) 2. An arm-shaped actuator 3 is arranged near the disk 1.

[0025] The base of actuator 3 is pivotally supported in a rotatable manner at a position offset from disk 1, and the front end of actuator 3 extends to near the center of disk 1. A voice coil motor (VCM) 4 is arranged at a position corresponding to the base of actuator 3, and the front end of actuator 3 rotates radially between the inner and outer circumferences of disk 1 by the power of the voice coil motor 4.

[0026] A magnetic head 10 corresponding to two-dimensional recording mode (TDMR) is disposed at the front end of the actuator 3. The magnetic head 10 has a write element 11 for writing magnetic data to the disk 1 and two read elements 12a and 12b for reading magnetic data from the disk 1, and moves radially (seek) on the disk 1 as the actuator 3 rotates.

[0027] The read elements (first read element) 12a and the read element (second read element) 12b are arranged along the rotation direction of the actuator 3 (radial direction of the disk 1). The spacing between the read elements 12a and 12b in the rotation direction of the actuator 3 (radial direction of the disk 1) is smaller than the width of each of the spiral patterns D1 to D2 (described later) written by the write element 11. Therefore, it is possible to align each of the read elements 12a and 12b with one spiral pattern.

[0028] The controller 20, which serves as the control center of the disk drive, is connected to a motor driver 21 that drives the spindle motor 2, a motor driver 22 that drives the voice coil motor 4, a signal processing circuit 23 that converts the data to be written to the disk 1 supplied by the controller 20 into an analog signal and amplifies it before supplying it to the write element 11, a signal processing circuit 24 that amplifies and converts the read signals of the read elements 12a and 12b into digital signals and supplies them to the controller 20, and a speedometer 30 that determines the moving speed (seek speed) of the read head 10.

[0029] like Figure 2 As shown, the speed table 30 stores a predetermined speed for the radial movement speed of the read / write head 10 of the disk 1, based on the position (seek position) of the read / write head 10. This predetermined speed is accelerated from zero to a certain value when the read / write head 10 moves from the innermost circumference to the outermost circumference (outward movement) and from the outermost circumference to the innermost circumference (return movement), and then decelerates to zero after maintaining this certain value.

[0030] The controller 20 controls the rotation of the disk 1 and the movement of the read / write head 10. As the main function related to writing to the reference pattern of the disk 1, it has a first control unit 20a, a second control unit 20b, a detection unit 20c, a correction unit 20d, a third control unit 20e, and a fourth control unit 20f.

[0031] While the disk 1 is rotating at a predetermined speed, the first control unit 20a moves the read / write head 10 radially from the innermost circumference to the outermost circumference of the disk 1 at a predetermined speed corresponding to the predetermined speed data in the speed table 30 (seeking), and writes a first reference pattern in the shape of a curve to the disk 1, which will become the reference for the predetermined processing of the disk 1, to the disk 1 using the write element 11.

[0032] The predetermined process is, for example, the process of writing a servo pattern to disk 1, which is used to detect the relative position of each track for data recording formed in concentric circles on disk 1 with the read / write head 10. This is called servo pattern writing process.

[0033] The second control unit 20b grasps the beginning of the first reference pattern written by the first control unit 20a using the read signals of the read elements 12a and 12b. In order to track the grasped first reference pattern using the read elements 12a and 12b, while the disk 1 is rotating at the aforementioned certain speed, the read head 10 is moved radially from the innermost circumference to the outermost circumference of the disk 1 at the aforementioned predetermined speed (seek).

[0034] The detection unit 20c detects (learns) the "deviation" (including "deviation direction" and "deviation amount") of the trajectory of the magnetic head 10, which is moved by the second control unit 20b to track the first reference pattern, and the first reference pattern written by the first control unit 20a by comparing the reading signals of the reading elements 12a and 12b, which are demodulated at the same timing.

[0035] The aforementioned "deviation direction" refers to the direction in which the written first reference pattern deviates from the radial inner or outer circumference of the head 10 relative to the movement trajectory of the head 10 when the written first reference pattern and the movement trajectory of the head 10 are inconsistent. For example, if the written first reference pattern deviates from the radial inner circumference of the head 10 relative to the movement trajectory of the head 10, then the "deviation direction" is the inner circumference. If the writing position of the written first reference pattern deviates from the radial outer circumference of the head 10 relative to the movement trajectory of the head 10, then the "deviation direction" is the outer circumference.

[0036] The aforementioned "deviation amount" refers to how much the written first reference pattern deviates radially from the trajectory of the head 10 when the written first reference pattern and the trajectory of the head 10 are inconsistent, successively showing the entire trajectory of the head 10.

[0037] The correction unit 20d corrects (updates) the specified speed in the direction that makes the "deviation" ("deviation amount") detected by the detection unit 20c disappear, and stores the corrected specified speed data corresponding to the corrected specified speed in the moving speed table 30.

[0038] While the disk 1 is rotating at the aforementioned certain speed, the third control unit 20e moves the head 10 radially from the innermost circumference to the outermost circumference of the disk 1 at a predetermined speed (corresponding to the corrected predetermined speed data) after being corrected by the correction unit 20d, and writes a curved second reference pattern, which will become the reference for the aforementioned predetermined processing, to the disk 1 using the write element 11 at a predetermined interval from the first reference pattern.

[0039] The fourth control unit 20f repeatedly performs the control of the first control unit 20a, the control of the second control unit 20b, the detection of the detection unit 20c, the correction of the correction unit 20d, and the control of the third control unit 20e. As a result, the first to Nth reference patterns in the curve shape that will become the reference for the above-mentioned predetermined processing are written to the disk 1 with a predetermined interval between them.

[0040] Next, while referring to Figure 3 The flowchart and the control performed by the controller 20 are explained.

[0041] When each reference pattern is written to disk 1, controller 20 sets the number of records K to "1" (S1) as initial processing. Then, as... Figure 4 As shown, while the disk 1 is rotating at a certain speed, the controller 20 moves the read / write head 10 radially from the innermost circumference to the outermost circumference of the disk 1 at a predetermined speed corresponding to the predetermined speed data in the speed table 30, and writes the first reference pattern, the so-called spiral pattern D1, based on the first line of the line number data K (=1), to the disk 1 using the write element 11 (S2).

[0042] The spiral pattern D1 is a magnetic pattern in which the magnetic intensity varies periodically along the writing direction, and is written to the disk 1 in a curved manner as the disk 1 rotates and the read / write head 10 moves. Figure 4 The diagram shows a spiral pattern D1 with a short total length, but it is also possible to write a spiral pattern D1 with a long total length that expands spirally from the inner periphery to the outer periphery of the disk 1 while repeatedly winding around the circumference of the disk 1.

[0043] Next, controller 20 determines whether the number of data entries K is less than N (S3). Since the number of data entries K (=1) at the current time point is less than N (S3's "yes"), therefore... Figure 5 As shown, the controller 20 grasps the beginning of the inner circumference of the written spiral pattern D1 using the read signals of the read elements 12a and 12b. In order to track the grasped spiral pattern D1 from its beginning to its end using the read elements 12a and 12b, while the disk 1 is rotating at the same speed as when the spiral pattern D1 is written, the magnetic head 10 moves radially from the innermost circumference to the outermost circumference of the disk 1 at the same speed as when the spiral pattern D1 is written (S4).

[0044] The width of the spiral pattern D1 in the direction orthogonal to the writing direction is larger than the spacing between the read elements 12a and 12b. The changes in the corresponding positions of the spiral pattern D1 and the read elements 12a and 12b, and the voltage waveforms of the output signals R1 and R2 of the corresponding read elements 12a and 12b are then compared. Figure 6 As shown in the image.

[0045] The larger the relative area of ​​reading element 12a with respect to spiral pattern D1, the larger the voltage amplitude of the output signal R1 of reading element 12a. Even if spiral pattern D1 and reading element 12a are not opposite each other, the closer the spiral pattern D1 is to reading element 12a, the larger the voltage amplitude of the output signal R1 of reading element 12a. The larger the relative area of ​​spiral pattern D1 and reading element 12b, the larger the voltage amplitude of the output signal R2 of reading element 12b. Even if spiral pattern D1 and reading element 12b are not opposite each other, the closer the spiral pattern D1 is to reading element 12b, the larger the voltage amplitude of the output signal R2 of reading element 12b.

[0046] Specifically, at position P1 where the reading elements 12a and 12b deviate from the spiral pattern D1 towards the right side of the diagram, the voltage amplitude of the output signal R1 of the reading element 12a, which is closer to the spiral pattern D1, is slightly present, while the voltage amplitude of the output signal R2 of the reading element 12b is zero. At positions P2 and P3 where only the reading element 12a is opposite to the spiral pattern D1, the voltage amplitude of the output signal R1 of the reading element 12a is large, while the voltage amplitude of the output signal R2 of the reading element 12b is small.

[0047] At position P4, where reading elements 12a and 12b are opposite to the spiral pattern D1 with equal areas, the voltage amplitudes of their output signals R1 and R2 increase to approximately the same level. At positions P5 and P6, where only reading element 12b is opposite to the spiral pattern D1, the voltage amplitude of reading element 12b's output signal R2 is large, while the voltage amplitude of reading element 12a's output signal R1 is small. At position P7, where reading elements 12a and 12b are offset from the spiral pattern D1 towards the left side of the diagram, the voltage amplitude of reading element 12b's output signal R2, which is closer to the spiral pattern D1, is slightly present, while the voltage amplitude of reading element 12a's output signal R1 becomes zero.

[0048] The controller 20 detects the “deviation” (including “deviation direction” and “deviation amount”) of the trajectory of the magnetic head 10 moving in order to track the spiral pattern D1 and the actual spiral pattern D1 written by comparing the voltage amplitude of the reading signals of the reading elements 12a and 12b on the entire moving trajectory of the magnetic head 10 (S5).

[0049] The trajectory of the read / write head 10, which moves to track the spiral pattern D1, corresponds to the target write position of the spiral pattern D1 determined according to a specified speed (initial value). An example of a "deviation" between the target write position and the actual write position of the spiral pattern D1 caused by various external forces within the disk device is shown in [the following text is incomplete and requires further context]. Figure 7 As shown in the image.

[0050] exist Figure 7 In the diagram, the dashed line shows the target write position (the trajectory of the read / write head 10) of the spiral pattern D1, and the solid line shows the actual write position of the spiral pattern D1. In this example, the actual write position of the spiral pattern D1 deviates from the target write position of the spiral pattern D1 in a manner that gradually bends towards the radial inner circumference of the disk 1. The distance between the actual write position of the spiral pattern D1 and the target write position of the spiral pattern D1 in the radial direction of the disk 1 is the aforementioned "deviation amount." In this case, the "deviation amount" gradually increases and then gradually decreases due to the aforementioned bending.

[0051] If the detected "deviation" exceeds the threshold ("No" in S6), the controller 20 repeatedly performs the above-mentioned processing S4 and processing S5 based on the judgment that the trajectory of the magnetic head 10 moving in order to track the spiral pattern D1 is inappropriate.

[0052] If the detected "deviation" is below the threshold (S6 "Yes"), the controller 20, based on the judgment that the movement of the magnetic head 10 is appropriate, corrects the specified speed in the direction that makes the detected "deviation" disappear, and stores the corrected specified speed data corresponding to the corrected specified speed in the movement speed table 30 (S7). The stored corrected specified speed data is then... Figure 2 It is shown in dashed lines.

[0053] Next, the controller 20 adds "1" to the count data K (=1) (K←K+1) and determines whether the count data K (=2) is more than N (S9). Since the count data K at this time point is less than N ("2" in S9), the controller 20 returns to S2 above. While the disk 1 is rotating at the same speed as when writing the spiral pattern D1, the read / write head 10 moves radially from the innermost circumference to the outermost circumference of the disk 1 at a corrected specified speed corresponding to the corrected specified speed data in the movement speed table 30. At the same time, the second reference pattern based on the count data K (=2), the so-called spiral pattern D2, is written to the disk 1 by the write element 11 with a predetermined interval from the spiral pattern D1 (S2).

[0054] Spiral pattern D2 is a magnetic pattern with the same magnetic intensity as spiral pattern D1, which changes periodically along the writing direction and is written in a curved shape as the disk 1 rotates and the read / write head 10 moves.

[0055] exist Figure 7 In the example, the trajectory (dashed line) of the target write position of the spiral pattern D2 corresponding to the aforementioned modified specified speed, and the actual write position (solid line) of the spiral pattern D2 actually written according to the aforementioned modified specified speed, are similar to the trajectory (dashed line) of the spiral pattern D1 written while being affected by various external forces within the disk device. Therefore, the spiral pattern D2 is written in a state where it does not intersect with the adjacent spiral pattern D1 and always maintains a predetermined interval with the spiral pattern D1. In this case, the "deviation," that is, the distance between the actual write position of the spiral pattern D2 and the target write position of the spiral pattern D2, is small.

[0056] Next, the controller 20 determines whether the number of data entries K is less than N (S3). Since the number of data entries K is less than N at this time point, which is "2" ("yes" in S3), the controller 20 uses the read signals of the read elements 12a and 12b to grasp the beginning of the inner circumference of the written spiral pattern D2. In order to track the grasped spiral pattern D2 from its beginning to its end using the read elements 12a and 12b, while the disk 1 is rotating at the same speed as when the spiral pattern D2 is written, the read head 10 moves radially from the innermost circumference to the outermost circumference of the disk 1 at the same modified prescribed speed as when the spiral pattern D2 is written (S4).

[0057] Then, the controller 20 detects the “deviation” (including “deviation direction” and “deviation amount”) between the trajectory of the magnetic head 10 moving in order to track the spiral pattern D2 and the actual spiral pattern D2 written by comparing the voltage amplitude of the read signal of the read elements 12a and 12b (S5).

[0058] If the deviation between the trajectory of the magnetic head 10, which moves to track the spiral pattern D2, and the actual written spiral pattern D2 is below a threshold (S6 "Yes"), the controller 20, based on the judgment that the movement of the magnetic head 10 is appropriate, corrects the aforementioned correction speed in the direction that makes the detected deviation disappear, and updates the correction speed data corresponding to the corrected speed in the movement speed table 30 (S7).

[0059] Next, the controller 20 adds "1" to the count data K (=2) (K←K+1) and determines whether the count data K (=2) is more than N (S9). Since the count data K at this time point is less than N ("3" in S9), the controller 20 returns to S2 above. While the disk 1 is rotating at the same speed as when writing the spiral pattern D2, the read / write head 10 moves radially from the innermost circumference to the outermost circumference of the disk 1 at a corrected speed corresponding to the updated corrected speed data in the speed table 30. At the same time, the third reference pattern based on the count data K (=3), the so-called spiral pattern D3, is written to the disk 1 using the write element 11 with a predetermined interval from the spiral pattern D2 (S2).

[0060] Spiral pattern D3 is a magnetic pattern with the same magnetic intensity as spiral patterns D1 and D2, which changes periodically along the writing direction and is written in a curved shape as the disk 1 rotates and the read / write head 10 moves.

[0061] exist Figure 7In the example, the trajectory (dashed line) of the target write position of the spiral pattern D3 corresponding to the aforementioned modified specified speed, and the actual write position (solid line) of the spiral pattern D3 actually written according to the aforementioned modified specified speed, are similar to the trajectory (dashed line) of the spiral pattern D2 written while being affected by various external forces within the disk device. Therefore, the spiral pattern D3 is written in a state where it does not intersect with the adjacent spiral pattern D2 and always maintains a predetermined interval with the spiral pattern D2. In this case, the "deviation," that is, the distance between the actual write position of the spiral pattern D3 and the target write position of the spiral pattern D3, is small.

[0062] Next, the controller 20 determines whether the number of data entries K is less than N (S3). Since the number of data entries K is less than N (S3) at this time point, the controller 20 uses the read signals of the read elements 12a and 12b to grasp the beginning of the inner circumference of the written spiral pattern D3. In order to track the grasped spiral pattern D3 from its beginning to its end using the read elements 12a and 12b, while the disk 1 is rotating at the same speed as when the spiral pattern D3 is written, the read head 10 moves radially from the innermost circumference to the outermost circumference of the disk 1 at the same modified speed as when the spiral pattern D3 is written (S4).

[0063] Then, the controller 20 detects the “deviation” (including “deviation direction” and “deviation amount”) between the trajectory of the magnetic head 10 moving to track the spiral pattern D3 and the actual written spiral pattern D3 by comparing the reading signals of the reading elements 12a and 12b (comparison of voltage amplitude) (S5).

[0064] If the deviation between the trajectory of the magnetic head 10, which moves to track the spiral pattern D3, and the actual written spiral pattern D3 is below a threshold (S6 "Yes"), the controller 20, based on the judgment that the movement of the magnetic head 10 is appropriate, re-corrects the aforementioned correction speed in the direction that makes the detected deviation disappear, and updates the correction speed data corresponding to the re-corrected correction speed in the movement speed table 30 (S7).

[0065] The controller 20 repeatedly performs the processes described in S1 to S9, while successively detecting (learning) the "deviation" of the write position of the first to "N-1" spiral patterns D1 to Dn-1 and successively correcting (updating) the prescribed speed in the direction that makes the "deviation" disappear, and writing the spiral patterns D2 to Dn sequentially based on the corrected prescribed speed. Thus, the first to Nth spiral patterns D1 to Dn can be written to the disk 1 at appropriate intervals where they do not intersect. Since the spiral patterns D1 to Dn do not intersect, subsequent servo pattern write processes can be executed appropriately.

[0066] Using the correspondence of the writing positions of previous spiral patterns as a reference, Figure 9 As shown in the diagram, because the specified speed data is always fixed, the interval between the written spiral patterns is unstable. In the worst case, multiple spiral patterns may even intersect each other. If this happens, servo pattern writing processing cannot be performed. In this embodiment, such an undesirable situation can be eliminated.

[0067] (Second Implementation)

[0068] Among the first control unit 20a, the second control unit 20b, the detection unit 20c, the correction unit 20d, the third control unit 20e, and the fourth control unit 20f of the controller 20, only the fourth control unit 20f differs from the first embodiment.

[0069] After executing the control of the first control unit 20a, the control of the second control unit 20b, the detection of the detection unit 20c, and the correction of the correction unit 20d, the fourth control unit 20f repeatedly performs the control of the third control unit 20e. As a result, the first to Nth reference patterns in the curve shape, which will become the reference for servo pattern writing processing, are written to the disk 1 with a predetermined interval between them.

[0070] like Figure 10 As shown in the flowchart, the control executed by the controller 20 replaces the processing of S3 and S4 in the first embodiment and has processing of S3a and S4a.

[0071] That is, after the controller 20 writes the first spiral pattern D1 based on the number of data K (=1), it determines whether the number of data K is 1 (S3a). If the number of data K is 1 (S3a "yes"), the controller 20, in order to track the spiral pattern D1 from its beginning to its end using the read elements 12a and 12b, moves the read / write head 10 radially from the innermost circumference to the outermost circumference of the disk 1 at the same modified prescribed speed as when writing the spiral pattern D2, while the disk 1 is rotating at the same speed as when writing the spiral pattern D2 (S4a). If the number of data K exceeds 1 (S3a "no"), the controller 20 moves to S8 and adds "1" to the number of data K (K←K+1). If the number of data K is less than N (S9 "no"), the processing from S2 onwards is repeated.

[0072] The other processes are the same as in the first embodiment.

[0073] That is, the controller 20 detects (learns) the "deviation" of the write position of the first spiral pattern D1, corrects (updates) the prescribed speed in the direction that makes the "deviation" disappear, and writes the second to Nth spiral patterns D2 to Dn based on the corrected prescribed speed. Thus, the first to Nth spiral patterns D1 to Dn can be written to the disk 1 at appropriate intervals without intersecting each other. Since the spiral patterns D1 to Dn do not intersect each other, subsequent servo pattern write processing can be performed appropriately.

[0074] The other structures and effects are the same as in the first embodiment.

[0075] (Modified Example)

[0076] In the above embodiments, the following structure can also be configured: when detecting the "deviation" of the writing position of the spiral pattern, the statistical average and weighted average of the detection results are calculated, and the specified speed is corrected based on the calculated results.

[0077] In the above embodiments, the following structure may also be adopted: when reading the specified speed data and correcting the specified speed data in the moving speed table 30, the read data is used after passing through a noise filter, etc., so that the value of the read data becomes a smooth value.

[0078] This invention is not limited to the embodiments described above. During implementation, the constituent elements can be modified and embodied by variations without departing from its spirit. Furthermore, various inventions can be formed through appropriate combinations of the multiple constituent elements disclosed in the above embodiments. For example, some constituent elements may be deleted from all the constituent elements shown in each embodiment. Moreover, constituent elements from different embodiments can be appropriately combined.

Claims

1. A disk drive, comprising: The magnetic head has a write element for writing data to a rotating disk and multiple read elements for reading data from the disk, and moves freely in the radial direction of the disk; and The controller controls the rotation of the disk and the movement of the read / write heads. The controller includes: The first control unit moves the read / write head radially along the disk at a predetermined speed while writing a first reference pattern to the disk using the write element, which serves as a reference for predetermined processing of the disk. The second control unit moves the magnetic head radially along the disk at the predetermined speed so that the first reference pattern written by the first control unit is tracked using each of the read elements. The detection unit uses the reading signals of each of the reading elements to detect the deviation between the trajectory of the magnetic head moved by the second control unit and the first reference pattern written by the first control unit; The correction unit corrects the predetermined speed in a direction that causes the deviation detected by the detection unit to disappear; and The third control unit moves the read / write head radially along the disk at a predetermined speed corrected by the correction unit, while using the write element to write a second reference pattern, which becomes the reference for the predetermined processing, to the disk at a predetermined interval from the first reference pattern.

2. The disk drive according to claim 1, The plurality of read elements are a first read element and a second read element arranged along the direction of movement of the magnetic head. The detection unit detects the deviation by comparing the reading signal of the first reading element with the reading signal of the second reading element.

3. The disk drive according to claim 1, The controller further includes a fourth control unit, which repeatedly executes the processing of the first control unit, the processing of the second control unit, the processing of the detection unit, the processing of the correction unit, and the processing of the third control unit to write the first to Nth reference patterns, which serve as the reference for servo pattern writing processing, to the disk at predetermined intervals.

4. The disk drive according to claim 1, The controller further includes a fourth control unit, which repeatedly executes the processing of the third control unit after executing the processing of the first control unit, the processing of the second control unit, the processing of the detection unit, and the processing of the correction unit, and writes the first to Nth reference patterns, which serve as the reference for servo pattern writing processing, to the disk with predetermined intervals between them.

5. The disk drive according to claim 1, The predetermined process is a servo pattern writing process that writes a servo pattern to the disk for detecting the relative position of each track of the data record formed on the disk with respect to the read / write head.

6. A method for writing a reference pattern, comprising: In a disk device having a write element for writing data to a rotatable disk, a read / write head that is freely movable in the radial direction of the disk and a controller for controlling the rotation of the disk and the movement of the read / write head, While moving the read / write head radially along the disk at a predetermined speed, the write element writes a first reference pattern to the disk, which serves as a reference for a predetermined process of the disk. The read / write head is moved radially along the disk at the specified speed so that the written first reference pattern is tracked using each of the read elements; The deviation between the trajectory of the magnetic head, which moves to track the first reference pattern, and the written first reference pattern is detected using the read signals of each of the read elements; The specified speed is corrected in the direction that makes the detected deviation disappear; as well as While moving the read / write head radially along the disk at the corrected specified speed, the write element writes a second reference pattern, which becomes the reference for the predetermined process, to the disk at a predetermined interval from the first reference pattern.

7. The reference pattern writing method according to claim 6, The predetermined process is a servo pattern writing process that writes a servo pattern to the disk for detecting the relative position of each track of the data record formed on the disk with respect to the read / write head.

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