Disk device and method of manufacturing disk device

Abstract

To provide a disk device capable of improving format efficiency.SOLUTION: According to one embodiment, there is provided a disk device including a head, a disk medium, and a controller. The disk medium includes a plurality of concentric zones. The controller is configured to generate timing correction data according to a radial position of a boundary area between two adjacent zones among the plurality of zones when writing two servo patterns corresponding to the two zones to a track in the boundary area with the head. The controller writes one of the two servo patterns to a track in the boundary area. The controller writes the other servo pattern at a position shifted in the circumferential direction from one servo pattern in the track of the boundary area according to the timing correction data.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present embodiment relates to a disk device and a method for manufacturing the disk device. [Background technology]

[0002] In disk drives that use the zone servo method, the disk medium is divided into multiple concentric zones, and servo patterns are written at different write frequencies in each zone. At the radial position of the zone boundary area, two servo patterns with different write frequencies are written together. In this case, it is desirable to improve format efficiency. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-130108 [Patent Document 2] U.S. Patent No. 8,531,794 [Patent Document 3] U.S. Patent No. 1,173,520 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of one embodiment is to provide a disk device and a method for manufacturing a disk device that can improve format efficiency. [Means for solving the problem]

[0005] According to one embodiment, a disk drive is provided that includes a head, a disk medium, and a controller. The disk medium includes a plurality of concentric zones. When the controller uses the head to write two servo patterns corresponding to two adjacent zones on a track in a boundary area between two of the plurality of zones, the controller generates timing correction data according to the radial position of the boundary area. The controller writes one of the two servo patterns on the track in the boundary area. The controller writes the other servo pattern at a position circumferentially shifted from one servo pattern on the track in the boundary area according to the timing correction data. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a diagram showing the configuration of a disk device according to an embodiment. [Figure 2] FIG. 2 is a diagram showing multiple zones of a disk medium according to an embodiment. [Figure 3] FIG. 10 is a diagram showing the relationship between the radial position and the write frequency in the embodiment. [Figure 4] 5A and 5B are diagrams showing servo patterns near zone boundary areas in an embodiment. [Figure 5] 5A and 5B are diagrams showing the relationship between the radial position and the attitude of the head in the embodiment. [Figure 6] FIG. 4 is a diagram showing the relationship between the radial position and the skew angle in the embodiment. [Figure 7] FIG. 10 is a diagram showing the relationship between the radial position and the RW circumferential offset in the embodiment. [Figure 8] 10A and 10B are diagrams showing the relationship between radial position and write timing offset in the embodiment. [Figure 9] 10 is a flowchart showing a flow of self-servo writing in the embodiment. [Figure 10] 5 is a flowchart showing a flow of learning a timing correction amount in the embodiment. [Figure 11] 6A and 6B are diagrams showing a circumferential gap between two servo patterns in a zone boundary area according to an embodiment. [Figure 12]10A and 10B are diagrams showing servo patterns in zone boundary areas in a modified example of the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0007] A disk drive according to an embodiment will be described in detail below with reference to the accompanying drawings, but the present invention is not limited to this embodiment.

[0008] (Embodiment) The disk device according to the embodiment employs a zone servo system in which the disk medium is divided into multiple concentric zones, and servo patterns are written at different write frequencies for each zone, but is also designed to improve the formatting efficiency of the zone boundary areas.

[0009] The disk device 1 can be configured as shown in Figure 1. Figure 1 is a diagram showing the configuration of the disk device 1.

[0010] The disk device 1 can be connected to the host 100 via a communication line. The communication line may be a wired communication path such as a serial cable. The disk device 1 is, for example, a hard disk drive or a magneto-optical disk drive. The host 100 is, for example, a personal computer or a processor.

[0011] As shown in FIG. 1, the disk device 1 includes a disk medium 10, a spindle motor (SPM) 11, a head 12, a suspension 13, a carriage arm 14, a voice coil motor (VCM) 15, a motor driver IC 20, a head IC 30, a buffer memory 90, and a controller 130.

[0012] The disk medium 10 is a disk-shaped recording medium, such as a magnetic disk or a magneto-optical disk, for recording various types of information. The disk medium 10 is rotated by the SPM 11. The disk medium 10 has, for example, multiple concentric zones centered near the center of rotation of the SPM 11. Each zone further has multiple concentric tracks. Each track has multiple data areas and servo areas (not shown) alternately arranged in the circumferential direction.

[0013] A head 12 is disposed above the disk medium 10. The head 12 includes a read element 12R and a write element 12W. The read element 12R and the write element 12W are disposed facing the disk medium 10 at a position that is lifted a predetermined height (for example, about 10 nm) above the disk medium 10.

[0014] The head 12 is held above the disk medium 10 via a suspension 13 and a carriage arm 14. The carriage arm 14 slides the head 12 within a horizontal plane during seek operations, etc. The suspension 13 applies a downward force to the head 12 that counters the lifting force of the head 12 caused by the airflow when the disk medium 10 is rotating, thereby maintaining a constant floating amount of the head 12 above the disk medium 10. The suspension 13 is made up of, for example, a leaf spring.

[0015] The VCM 15 drives the carriage arm 14. The SPM 11 rotates the disk medium 10 around a spindle 11a. The VCM 15 and SPM 11 are fixed to the housing.

[0016] The head IC 30 has a write current control unit 30a and a read signal detection unit 30b, and amplifies and detects signals during recording and reproduction. The write current control unit 30a controls the write current flowing through the write element 12W. The read signal detection unit 30b detects the signal read by the read element 12R.

[0017] The motor driver IC 20 includes an SPM control unit 20a and a VCM control unit 20b, and drives the SPM 11 and VCM 15. The SPM control unit 20a controls the rotation of the SPM 11. The VCM control unit 20b controls the driving of the VCM 15.

[0018] The controller 130 has a head IC 30, a motor driver IC 20, a read / write channel (RWC) 40, an HDC 50, a processor 60, a volatile memory 70, and a non-volatile memory 80, and controls each part of the disk device 1. As a result, the controller 130 controls the radial positions (radial positions) of the read element 12R and the write element 12W relative to the disk medium 10, for example, based on servo information read by the read element 12R.

[0019] The RWC 40 exchanges data between the head IC 30 and the HDC 50. The data includes read data, write data, and servo information. For example, the RWC 40 converts signals reproduced by the read element 12R into a data format handled by the host 100, and converts data output from the host 100 into a signal format to be recorded by the write element 12W. The RWC 40 also decodes signals reproduced by the read element 12R and code-modulates data output from the host 100.

[0020] The HDC 50 performs read / write control based on commands from the host 100, and transfers data between the host 100 and the RWC 40, for example.

[0021] The processor 60 performs servo processing. The servo processing includes decoding servo information, reading the servo information, and determining the position of the head 12 based on the servo information. The processor 60 demodulates the position of the head 12 in response to the read signal received from the RWC 40, and determines the error (position error) of the demodulated position from the target position. The processor 60 determines a control amount corresponding to the position error.

[0022] The processor 60 has a zone servo switching unit 60a and an estimation observer 60b. The estimation observer 60b estimates the radial position of the head 12 on the disk medium 10, for example, from the past position history of the head 12. The processor 60 identifies which zone of the disk medium 10 the head 12 is in based on the estimated radial position. The zone servo switching unit 60a switches the write frequency SFG of the servo pattern in servo processing based on which zone of the disk medium 10 the head 12 is in. The zone servo switching unit 60a may switch the write frequency of each zone so that the write frequency of the outer zone is higher than that of the inner zone.

[0023] The volatile memory 70 is capable of temporarily storing data and / or information received from the HDC 50. The volatile memory 70 functions as a working area for the HDC 50.

[0024] The nonvolatile memory 80 stores various setting parameters necessary for the operation of the disk device 1, the setting value of the write frequency SFG set for each zone, and the past position history of the head 12 used by the estimation observer 60b to calculate the estimated position.

[0025] The disk device 1 reads a signal from the disk medium 10 via the head 12 while rotating the disk medium 10 with the SPM 11, and the read signal detector 30b detects the read signal as a read signal. The read signal is converted into read information by the RWC 40 and then sent to the processor 60. The processor 60 performs tracking control of the head 12 based on the servo information included in the read information.

[0026] The processor 60 calculates the current position of the head 12 based on the servo information and performs seek control so that the head 12 approaches the target position. When the head 12 reaches the target position, a signal is read from the disk medium 10 via the head 12, or data or information is written to the disk medium 10.

[0027] The disk device 1 employs a zone servo system, and the disk medium 10 is divided into a plurality of concentric zones Z1 to Z6 as shown in Figure 2. Figure 2 is a diagram showing the plurality of zones Z1 to Z6 on the disk medium 10. Figure 2 illustrates an example in which six zones Z1 to Z6 are provided on the disk medium 10, but the number of zones Z provided on the disk medium 10 may be two to five, or seven or more. Hereinafter, the direction opposite to the rotation direction of the disk medium 10 will be referred to as the circumferential direction.

[0028] The disk drive 1 rotates the disk medium 10 around the spindle 11a at a predetermined rotation speed in a clockwise direction in FIG. 2, and moves the head 12 in the circumferential direction indicated by the dashed-dotted arrow in FIG. 2. As a result, the disk drive 1 writes servo patterns SV at different write frequencies for each of the zones Z1 to Z6 using the write element 12W. For simplicity's sake, FIG. 2 illustrates an example in which a single row of servo patterns SV is aligned in the radial direction, but a similar row of servo patterns SV may be written repeatedly in the circumferential direction on the disk medium 10. The servo patterns SV may be written at a higher write frequency SFG in the zones Z closer to the outer periphery, since the speed of the head 4 in the circumferential direction increases.

[0029] For example, as shown in FIG. 3, the disk device 1 writes a servo pattern SV at a write frequency SFG1 in zone Z1. The disk device 1 writes a servo pattern SV at a write frequency SFG2 (>SFG1) in zone Z2. The disk device 1 writes a servo pattern SV at a write frequency SFG3 (>SFG2) in zone Z3. The disk device 1 writes a servo pattern SV at a write frequency SFG4 (>SFG3) in zone Z4. The disk device 1 writes a servo pattern SV at a write frequency SFG5 (>SFG4) in zone Z5. The disk device 1 writes a servo pattern SV at a write frequency SFG6 (>SFG5) in zone Z6.

[0030] At this time, the disk drive 1 mixes servo patterns SV with write frequencies SFG1 and SFG2 at radial position TR_n in the boundary region between zones Z1 and Z2. The disk drive 1 mixes servo patterns SV with write frequencies SFG2 and SFG3 at radial position TR_2n in the boundary region between zones Z2 and Z3. The disk drive 1 mixes servo patterns SV with write frequencies SFG3 and SFG4 at radial position TR_3n in the boundary region between zones Z3 and Z4. The disk drive 1 mixes servo patterns SV with write frequencies SFG4 and SFG5 at radial position TR_4n in the boundary region between zones Z4 and Z5. The disk drive 1 mixes servo patterns SV with write frequencies SFG5 and SFG6 at radial position TR_5n in the boundary region between zones Z5 and Z6. Although FIG. 3 illustrates a configuration in which each zone boundary area includes one radial position that is to become a track, each zone boundary area may include multiple radial positions that are to become tracks.

[0031] In the manufacturing process, a blank disk write (BDW) is performed to write a spiral pattern onto the disk medium 10. Spiral information in the spiral pattern defines a plurality of concentric radial positions TR on the disk medium 10. When a zone servo system is employed, the plurality of radial positions TR are grouped into a plurality of zones Z, each of which includes one or more radial positions TR.

[0032] In the self-servo write (SSW) process of a disk drive 1 employing a zone servo system, servo patterns SV with different write frequencies SFG are written in each of multiple zones Z, as shown in FIGS. 4(a) to 4(d). FIG. 4 shows servo patterns SV near zone boundary areas. In the SSW process, the disk drive 1 also writes an erase pattern ER at the circumferential end of each servo pattern SV. The disk drive 1 forms this pattern by supplying a high-frequency current to the write element 12W and performing a radial magnetic erase, i.e., AC band erase, process.

[0033] For example, if zone Z1 includes radial positions TR_1 to TR_n, and zone Z2 includes radial positions TR_n to TR_2n, then radial position TR_n is the radial position of the zone boundary region, where n is any integer of 2 or greater.

[0034] At the radial position TR_n of the zone boundary area, two types of servo patterns SV1 and SV2 are written with a circumferentially shifted timing, as shown in Fig. 4(c). Of the two types of servo patterns SV1 and SV2 at the radial position TR_n of the boundary area, the servo pattern SV1 on the upstream side in the circumferential direction is sometimes called the front servo pattern, and the servo pattern SV2 on the downstream side in the circumferential direction is sometimes called the back servo pattern.

[0035] The disk drive 1 writes the front servo pattern SV1 at a write frequency SFG1, and writes an erase pattern ER11 (shown by a dotted line in FIG. 4C) at the circumferential end of the front servo pattern SV1. The disk drive 1 may write the erase pattern ER11 with a circumferential length corresponding to the circumferential length of the postcode PC. The disk drive 1 writes the rear servo pattern SV2 at a write frequency SFG2 (>SFG1) so that the erase pattern ER11 overlaps the erase pattern ER11 from a position separated by a circumferential gap ΔG1 from the circumferential end of the front servo pattern SV1, and writes an erase pattern ER12 at the circumferential end of the rear servo pattern SV2. This leaves an erase pattern ER11a with a circumferential gap ΔG1 between the front servo pattern SV1 and the rear servo pattern SV2. The disk drive 1 may write the erase pattern ER12 with a circumferential length corresponding to twice the circumferential length of the postcode PC.

[0036] At this time, at radial position TR_n-1 adjacent to radial position TR_n on the inner peripheral side, the disk drive 1 writes a servo pattern SV1 at a write frequency SFG1 and writes an erase pattern ER1 at the circumferential end of the servo pattern SV1, as shown in Fig. 4(b). The disk drive 1 may write the erase pattern ER1 with a circumferential length corresponding to the circumferential length of the postcode PC.

[0037] At radial position TR_n+1 adjacent to radial position TR_n on the outer circumferential side, the disk drive 1 writes a servo pattern SV2 at a write frequency SFG2 and writes an erase pattern ER2 at the circumferential end of the servo pattern SV2, as shown in Fig. 4(d). The disk drive 1 may write the erase pattern ER2 with a circumferential length corresponding to the circumferential length of the postcode PC.

[0038] As shown in Figure 4(a), each servo pattern SV written in the SSW process includes a preamble PR, a sync mark SM, a Gray code GC, a burst pattern BS1, and a burst pattern BS2, arranged in that order in the circumferential direction. The preamble PR is a reference pattern for synchronizing the amplitude and phase with the servo pattern SV. The sync mark SM is a pattern that indicates a reference position in the circumferential direction on the track. The Gray code GC includes information (e.g., a number) that indicates a radial position on the disk medium 10. The burst pattern BS1 and the burst pattern BS2 include patterns that are shifted from each other in the radial direction, and are used together to detect the amount of off-track of the head 12 from the track center.

[0039] After the SSW process, the disk device 1 performs postcode writing as shown in FIGS. 4(e) to 4(g). The postcode PC is written by overwriting the erase pattern ER. The postcode PC includes information on the correction amount (such as eccentricity correction amount) for correcting off-track errors obtained from the burst patterns BS1 and BS2. The erase pattern ER corresponds to the postcode PC, and its circumferential length is slightly longer than that of the postcode PC.

[0040] For example, at radial position TR_n in the zone boundary area, the disk device 1 writes multiple postcodes PC1 and PC2 in order to overwrite the erase pattern ER12, as shown in FIG. 4(f). Postcode PC1 corresponds to servo pattern SV1, and postcode PC2 corresponds to servo pattern SV2. An erase pattern ER12a remains at the end of postcode PC2. This reduces the margin area between postcode PC1 and servo pattern SV2 compared to when servo pattern SV1, postcode PC1, servo pattern SV2, and postcode PC2 are written in order, thereby improving the format efficiency of the servo patterns SV1 and SV2.

[0041] At this time, at radial position TR_n-1 adjacent to radial position TR_n on the inner circumferential side, the disk device 1 overwrites the erase pattern ER1 with the postcode PC1, as shown in Fig. 4(e), leaving an erase pattern ER1a at the end of the postcode PC1.

[0042] At radial position TR_n+1, which is adjacent to radial position TR_n on the outer circumferential side, the disk device 1 overwrites the erase pattern ER2 with the postcode PC2, as shown in Fig. 4(g), leaving an erase pattern ER2a at the end of the postcode PC2.

[0043] Fig. 4 illustrates the configuration of a servo pattern near radial position TR_n in a zone boundary area, but the configurations of servo patterns near radial positions TR_2n, TR_3n, TR_4n, and TR_5n in the other zone boundary areas shown in Fig. 2 are similar. Also, Fig. 4 illustrates a configuration in which each zone boundary area includes one radial position that should become a track, but each zone boundary area may include multiple radial positions that should become tracks.

[0044] Here, let us consider making the circumferential gaps ΔG of the multiple servo patterns SV equal between the radial positions TR of each zone boundary region. In this case, in addition to differences in write frequency between zones, we also consider differences in the circumferential offset between the read element 12R and the write element 12W of the head 12 (hereinafter referred to as the RW circumferential offset). The circumferential offset indicates the spatial deviation in the circumferential direction between the circumferential positions of the read element 12R and the write element 12W when the head 12 is in a specified posture.

[0045] 2, the arm angle of the carriage arm 14 changes depending on the radial position (radial position TR_n, TR_2n, TR_3n, TR_4n, TR_5n) at which the head 12 is located, and therefore the skew angle α of the head 12 changes. Accordingly, the relative positional relationship between the read element 12R and the write element 12W with respect to the disk medium 10 also changes, and so the RW circumferential offset OF also changes.

[0046] When the head 12 is positioned at a radial position TR_n in the boundary region between zones Z1 and Z2 during tracking, the positional relationship between the read element 12R and the write element 12W when viewed from the disk medium 10 is as shown in Figure 5(a). That is, the skew angle α becomes a negative angle α1 (<0) tilted toward the inner periphery, and the RW circumferential offset OF becomes a relatively small value OF1. Figure 4 shows the relationship between the radial position and the attitude of the head 12.

[0047] When the head 12 is positioned at radial position TR_3n in the boundary area between zones Z3 and Z4 during tracking, the positional relationship between the read element 12R and the write element 12W when viewed from the disk medium 10 is as shown in Figure 5(b). That is, the skew angle α is approximately zero (α2) (≈0), and the RW circumferential offset OF is a relatively large value OF2 (>OF1).

[0048] When the head 12 is positioned at a radial position TR_5n in the boundary area between the zones Z5 and Z6 during tracking, the positional relationship between the read element 12R and the write element 12W when the head 12 is viewed from the disk medium 10 side is as shown in Figure 5(c). That is, the skew angle α becomes a positive angle α3 (>0) inclined toward the outer periphery, and the RW circumferential offset OF becomes a relatively small value OF3 ( <OF2)となる。

[0049] The relationship between the radial position and the skew angle α shown in Fig. 5 can be organized for each radial position as shown in Fig. 6, and the relationship between the radial position and the RW circumferential offset OF shown in Fig. 5 can be organized for each radial position as shown in Fig. 7. Fig. 6 is a diagram showing the relationship between the radial position and the skew angle α. Fig. 7 is a diagram showing the relationship between the radial position and the RW circumferential offset OF.

[0050] 6, the skew angle α can change monotonically with the change in radial position. As the radial position moves from the outer periphery to the inner periphery, the skew angle α can decrease monotonically in the positive region, become approximately zero near the radial position TR_3n, and decrease monotonically in the negative region.

[0051] 7, the RW circumferential offset exhibits a mountain-like change with respect to the change in radial position. As the radial position moves from the outer circumferential side to the inner circumferential side, the RW circumferential offset gradually increases, reaches a peak near the radial position TR_3n, and then gradually decreases.

[0052] For example, in the disk device 1, the controller 130 may experimentally obtain and store in advance the relationship of the radial position shown in FIG. 6. The controller 130 can determine the relationship between the radial position and the RW circumferential offset OF shown in FIG. 7 using the relationship between the radial position and the write frequency shown in FIG. 3 and the relationship between the radial position and the skew angle α shown in FIG. 6. The controller 130 can calculate the time influence within one rotation by the SPM 11 using the relationship between the radial position and the write frequency shown in FIG. 3 and the relationship between the radial position and the RW circumferential offset OF shown in FIG. 7. The controller 130 can determine the write timing offset for each radial position as shown in FIG. 8 based on the calculation result. FIG. 8 is a diagram showing the relationship between the radial position and the write timing offset. The write timing offset indicates a time difference in the write timing.

[0053] The controller 130 calculates the write timing offset for each radial position by taking into account dimensional variations between devices and using the results of measuring the RW circumferential offset when the device is mounted. However, it may also be calculated from theoretical mechanical dimensions. The controller 130 generates timing correction data according to the write timing offset for each radial position and stores it in a management information storage area. The management information storage area is a storage area for storing management information and may be provided in the non-volatile memory 80 or in the disk medium 10. The controller 130 may read the timing correction data for each radial position from the management information storage area during SSW in each zone and correct the write start timing of each servo pattern according to the timing correction data. Alternatively, the controller 130 may sequentially learn the write start timing of servo patterns in the same zone and correct it separately from the timing correction proposed herein.

[0054] Next, a description will be given of a manufacturing method of the disk device 1. In the manufacturing method of the disk device 1, a blank disk write (BDW) process, a self-servo write (SSW) process, and a postcode write process are carried out in this order.

[0055] In the BDW process, a blank disk medium 10 is mounted in the housing of the disk device 1, and the disk device 1 is assembled. The disk device 1 writes a spiral pattern onto the blank disk medium 10.

[0056] In the SSW process, the disk device 1 writes the servo pattern SV using a spiral pattern as shown in Fig. 9. Fig. 9 is a flowchart showing the flow of self-servo writing.

[0057] The disk device 1 causes the head 12 to seek to the SSW start position (S1).

[0058] For example, the disk device 1 selects a write target zone Z from among multiple zones Z1 to Z6. The disk device 1 sets the representative radial position TR in the write target zone Z as the SSW start position. The representative radial position TR may be the first radial position TR in the write target zone Z. The disk device 1 uses a spiral pattern to cause the head 12 to seek to the representative radial position TR.

[0059] The disk device 1 learns the amount of eccentricity correction and the amount of timing correction (S2).

[0060] For example, the disk device 1 measures the rotation-synchronous component of the housing using an acceleration sensor or the like provided in the housing, calculates the eccentricity correction amount based on the measurement result, and stores the amount in association with the current radial position. In this way, the disk device 1 learns the eccentricity correction amount.

[0061] Furthermore, the disk device 1 learns the timing correction amount as shown in Fig. 10. Fig. 10 is a flowchart showing the flow of learning the timing correction amount.

[0062] The disk device 1 measures the radial RW offset RF over the entire surface of the disk medium 10 (S21).

[0063] For example, in the disk drive 1, the controller 130 selects a radial position TR to be measured from among multiple radial positions TR in the write-target zone Z, and controls the positioning of the write element 12W to the radial center of the selected radial position TR. The controller 130 writes a predetermined pattern with the write element 12W while tracking the write element 12W to the radial center of the selected radial position TR. The controller 130 alternately shifts the head 12 in the radial direction and reads with the read element 12R. After the predetermined pattern has been read, the controller 130 determines the total radial shift amount of the head 12 as the radial RW offset RF. The controller 130 performs this measurement for each of the multiple radial positions TR.

[0064] The disk device 1 uses the measurement result of S21 to calculate the circumferential timing correction amount (S22).

[0065] For example, the controller 130 accesses the management information storage area, refers to the relationship between the radial position and the skew angle α (see FIG. 6), and calculates the skew angle α for each radial position TR. The controller 130 calculates the RW circumferential offset OF using the skew angle α and the measurement result of S21. If α≠0, the controller 130 can convert the radial RW offset RF measured by S21 into the RW circumferential offset OF using the following equation 1. OF=RF / (tanα)...Formula 1 If α≒0, the controller 130 can use the distance between the write element 12W and the read element 12R in the XY plane direction as the RW circumferential offset OF without using the radial RW offset RF measured in S21 (see Figure 5(b)).

[0066] This allows the controller 130 to obtain the relationship between each radial position and the RW circumferential offset OF as shown in FIG.

[0067] The controller 130 accesses the management information storage area, refers to the relationship between the radial position and the write frequency (see FIG. 3), and obtains the write frequency SFG for each radial position TR. At this time, for the radial positions TR_n, TR_2n, TR_3n, TR_4n, and TR_5n in the zone boundary area, the controller 130 may use any one of the values ​​of the write frequencies SFG of the multiple servo patterns SV as the write frequency SFG, or may use the average value of the write frequencies SFG of the multiple servo patterns SV.

[0068] The controller 130 calculates the write timing offset RT for each radial position TR using the write frequency SFG. The controller 130 can convert the RW circumferential offset OF into the write timing offset RT using the following Equation 2. RT = (ΔG + OF) / (SFG × K) Equation 2

[0069] In Equation 2, ΔG is a target value of the circumferential gap between the servo patterns SV, and K is a coefficient for converting frequency into speed, which can be determined experimentally in advance.

[0070] At this time, a reference zone Z may be determined, and the error of the write timing offset RT from the reference zone Z may be used as the write timing offset correction amount ΔRT for the zones Z other than the reference zone.

[0071] For example, when zone Z1 is set as the reference zone, the disk device 1 sets the write timing offset RT_1 at the leading radial position TR_1 of zone Z1 as the reference write timing offset.

[0072] The disk device 1 can obtain the write timing offset correction amount ΔRT_n for the write timing offset RT_n of the rear servo pattern SV at the radial position TR_n in the boundary area between the zones Z1 and Z2 by the following equation 3. ΔRT_n=RT_n - RT_1 Equation 3

[0073] The disk device 1 can obtain the write timing offset correction amount ΔRT_2n for the write timing offset RT_2n of the rear servo pattern SV at the radial position TR_2n in the boundary area between the zones Z2 and Z3 by the following equation 4. ΔRT_2n=RT_2n - RT_1...Formula 4

[0074] The disk device 1 can calculate the write timing offset correction amount ΔRT_3n for the write timing offset RT_3n of the rear servo pattern SV at the radial position TR_3n in the boundary area between the zones Z3 and Z4 by the following equation 5. ΔRT_3n=RT_3n - RT_1...Formula 5

[0075] The disk device 1 can obtain the write timing offset correction amount ΔRT_4n for the write timing offset RT_4n of the rear servo pattern SV at the radial position TR_4n in the boundary area between the zones Z4 and Z5 by the following equation 6. ΔRT_4n=RT_4n - RT_1 Equation 6

[0076] The disk device 1 can calculate the write timing offset correction amount ΔRT_5n for the write timing offset RT_5n of the rear servo pattern SV at the radial position TR_5n in the boundary area between the zones Z5 and Z6 by the following equation 7. ΔRT_5n=RT_5n - RT_1 Equation 7

[0077] This allows the controller 130 to determine the write timing offset correction amount ΔRT as the circumferential timing correction amount.

[0078] The disk device 1 generates timing correction data using the circumferential timing correction amount calculated in S22 and stores the data in the management information storage area (S23).

[0079] For example, the controller 130 generates timing correction data for each radial position TR using the write timing offset correction amount ΔRT calculated in S22. The controller 130 generates timing correction data in which identification information (e.g., number) of the radial position TR and the write timing offset correction amount ΔRT are associated with each other for a plurality of radial positions TR. The controller 130 stores the timing correction data in the management information storage area.

[0080] 9, the disk device 1 performs timing correction using the timing correction amount learned in S22 (S3). The disk device 1 adds the calculated circumferential timing offset RT to the baseline of the time-direction write timing learned value (timing correction data) updated at the start of SSW, and corrects the timing of the entire zone so that no deviation occurs at the zone boundary area.

[0081] For example, the disk device 1 reads the timing correction data S23 from the management information storage area and identifies the timing correction amount for each of the radial positions TR_n, TR_2n, TR_3n, TR_4n, and TR_5n in the zone boundary area. The disk device 1 uses the identified timing correction amount to correct the write start timing of the front servo pattern SV and / or the rear servo pattern SV.

[0082] When zone Z1 is set as the reference zone, the disk device 1 identifies a write timing offset correction amount ΔRT_n for a radial position TR_n in the boundary area between zones Z1 and Z2. The disk device 1 corrects the write start timing of the subsequent servo pattern SV for the radial position TR_n in the boundary area between zones Z1 and Z2 using the write timing offset correction amount ΔRT_n. The disk device 1 determines the write start timing of the subsequent servo pattern SV to be the timing obtained by adding the write timing offset correction amount ΔRT_n to the baseline of the write timing learned value. The disk device 1 also corrects the write start timing of the servo pattern SV for radial positions TR_n+1 to TR_2n-1 in zone Z2 using the write timing offset correction amount ΔRT_n. The disk device 1 determines the write start timing of the servo pattern SV to be the timing obtained by adding the write timing offset correction amount ΔRT_n to the baseline of the write timing learned value.

[0083] The disk device 1 identifies a write timing offset correction amount ΔRT_2n for a radial position TR_2n in the boundary area between zones Z2 and Z3. For the radial position TR_2n in the boundary area between zones Z2 and Z3, the disk device 1 corrects the write start timing of the front servo pattern SV using the write timing offset correction amount ΔRT_2n, and corrects the write start timing of the back servo pattern SV using the write timing offset correction amount ΔRT_n. The disk device 1 determines the write start timing of the front servo pattern SV as the timing obtained by adding the write timing offset correction amount ΔRT_2n to the baseline of the write timing learned value, and determines the write start timing of the back servo pattern SV as the timing obtained by adding the write timing offset correction amount ΔRT_n to the baseline of the write timing learned value. The disk device 1 also corrects the write start timing of the servo patterns SV for radial positions TR_2n+1 to TR_3n-1 in zone Z3 using the write timing offset correction amount ΔRT_2n. The disk device 1 sets the timing obtained by adding the write timing offset correction amount ΔRT_2n to the baseline of the write timing learned value as the write start timing for the servo pattern SV.

[0084] The disk device 1 identifies a write timing offset correction amount ΔRT_3n for a radial position TR_3n in the boundary area between zones Z3 and Z4. For the radial position TR_3n in the boundary area between zones Z3 and Z4, the disk device 1 corrects the write start timing of the front servo pattern SV using the write timing offset correction amount ΔRT_2n, and corrects the write start timing of the back servo pattern SV using the write timing offset correction amount ΔRT_3n. The disk device 1 determines the write start timing of the front servo pattern SV as the timing obtained by adding the write timing offset correction amount ΔRT_3n to the baseline of the write timing learned value, and determines the write start timing of the back servo pattern SV as the timing obtained by adding the write timing offset correction amount ΔRT_2n to the baseline of the write timing learned value. The disk device 1 also corrects the write start timing of the servo patterns SV for radial positions TR_3n+1 to TR_4n-1 in zone Z4 using the write timing offset correction amount ΔRT_3n. The disk device 1 sets the timing obtained by adding the write timing offset correction amount ΔRT_3n to the baseline of the write timing learned value as the write start timing for the servo pattern SV.

[0085] The disk device 1 identifies a write timing offset correction amount ΔRT_4n for a radial position TR_4n in the boundary area between zones Z4 and Z5. For the radial position TR_4n in the boundary area between zones Z4 and Z5, the disk device 1 corrects the write start timing of the front servo pattern SV using the write timing offset correction amount ΔRT_4n, and corrects the write start timing of the rear servo pattern SV using the write timing offset correction amount ΔRT_3n. The disk device 1 determines the write start timing of the front servo pattern SV as the timing obtained by adding the write timing offset correction amount ΔRT_4n to the baseline of the write timing learned value, and determines the write start timing of the rear servo pattern SV as the timing obtained by adding the write timing offset correction amount ΔRT_3n to the baseline of the write timing learned value. The disk device 1 also corrects the write start timing of the servo patterns SV for radial positions TR_4n+1 to TR_5n-1 in zone Z5 using the write timing offset correction amount ΔRT_4n. The disk device 1 determines the timing obtained by adding the write timing offset correction amount ΔRT_4n to the baseline of the write timing learned value as the write start timing for the servo pattern SV.

[0086] The disk device 1 identifies a write timing offset correction amount ΔRT_5n for a radial position TR_5n in the boundary area between zones Z5 and Z6. For the radial position TR_5n in the boundary area between zones Z5 and Z6, the disk device 1 corrects the write start timing of the front servo pattern SV using the write timing offset correction amount ΔRT_5n, and corrects the write start timing of the rear servo pattern SV using the write timing offset correction amount ΔRT_4n. The disk device 1 determines the write start timing of the front servo pattern SV as the timing obtained by adding the write timing offset correction amount ΔRT_5n to the baseline of the write timing learned value, and determines the write start timing of the rear servo pattern SV as the timing obtained by adding the write timing offset correction amount ΔRT_4n to the baseline of the write timing learned value. The disk device 1 also corrects the write start timing of the servo patterns SV for radial positions TR_5n+1 to TR_6n-1 in zone Z6 using the write timing offset correction amount ΔRT_5n. The disk device 1 sets the timing obtained by adding the write timing offset correction amount ΔRT_5n to the baseline of the write timing learned value as the write start timing for the servo pattern SV.

[0087] The disk device 1 starts SSW of the corresponding zone Z using the correction result of S3 (S4).

[0088] For example, as shown in Fig. 11, the disk device 1 writes a servo pattern SV1 at a timing according to the write timing offset RT for radial positions TR_1 to TR_n-1 in zone Z1. Fig. 11 is a diagram showing a circumferential gap ΔG between two servo patterns SV in a zone boundary area.

[0089] The disk device 1 writes the front servo pattern SV1 at a radial position TR_n in the boundary area between the zones Z1 and Z2 at a timing corresponding to the write timing offset RT, and writes the rear servo pattern SV2 at a timing corrected by the write timing offset correction amount ΔRT_n, thereby adjusting the circumferential gap between the servo patterns SV1 and SV2 to ΔG1.

[0090] The disk device 1 writes the servo pattern SV2 at the timing corrected by the write timing offset correction amount ΔRT_n for the radial positions TR_n+1 to TR_2n−1 in the zone Z2.

[0091] The disk device 1 writes the front servo pattern SV3 at a radial position TR_2n on the boundary between zones Z2 and Z3 at a timing corrected by the write timing offset correction amount ΔRT_2n, and writes the rear servo pattern SV2 at a timing corrected by the write timing offset correction amount ΔRT_n, thereby adjusting the circumferential gap between the servo patterns SV3 and SV2 to ΔG2 (≈ΔG1).

[0092] The disk device 1 writes the servo pattern SV3 at the timing corrected by the write timing offset correction amount ΔRT_2n for the radial positions TR_2n+1 to TR_3n−1 in the zone Z3.

[0093] The disk device 1 writes the front servo pattern SV3 at the radial position TR_3n on the boundary between the zones Z3 and Z4 at a timing corrected by the write timing offset correction amount ΔRT_2n, and writes the rear servo pattern SV4 at a timing corrected by the write timing offset correction amount ΔRT_3n, thereby adjusting the circumferential gap between the servo patterns SV3 and SV4 to ΔG3 (≈ΔG1).

[0094] The disk device 1 writes the servo pattern SV4 at the radial positions TR_3n+1 to TR_4n-1 in the zone Z4 at timing corrected by the write timing offset correction amount ΔRT_3n.

[0095] The disk device 1 writes the front servo pattern SV5 at the radial position TR_4n on the boundary between the zones Z4 and Z5 at a timing corrected by the write timing offset correction amount ΔRT_4n, and writes the rear servo pattern SV4 at a timing corrected by the write timing offset correction amount ΔRT_3n, thereby adjusting the circumferential gap between the servo patterns SV5 and SV4 to ΔG4 (≈ΔG1).

[0096] The disk device 1 writes the servo pattern SV5 at the radial positions TR_4n+1 to TR_5n-1 in the zone Z5 at timings corrected by the write timing offset correction amount ΔRT_4n.

[0097] The disk device 1 writes the front servo pattern SV5 at the radial position TR_5n on the boundary between the zones Z5 and Z6 at a timing corrected by the write timing offset correction amount ΔRT_4n, and writes the rear servo pattern SV6 at a timing corrected by the write timing offset correction amount ΔRT_5n, thereby adjusting the circumferential gap between the servo patterns SV5 and SV6 to ΔG5 (≒ΔG1).

[0098] The disk device 1 writes the servo pattern SV6 at the timing corrected by the write timing offset correction amount ΔRT_5n for the radial positions TR_5n+1 to TR_6n−1 in the zone Z6.

[0099] As shown in FIG. 11, the circumferential gap ΔG between the servo patterns in each zone boundary area can be uniform.

[0100] As described above, in the disk device 1 of this embodiment, the controller 130 writes one of the two servo patterns SV in a track in a zone-Z boundary area at a position shifted circumferentially from the other servo pattern in accordance with the timing correction data. This makes it possible to equalize the circumferential gap ΔG between the two servo patterns SV in the track in the zone-Z boundary area between the respective zone boundary areas, thereby ensuring a wide area in which data can be recorded, thereby improving format efficiency.

[0101] The disk device 1 may experimentally obtain in advance RW offset information indicating the relationship between each radial position on the disk medium 10 and the radial RW offset RF, and store the information in the management information storage area. In this case, in S21 of Fig. 10, the disk device 1 can obtain the radial RW offset RF for each of the multiple radial positions TR by reading the RW offset information from the management information storage area instead of performing measurements.

[0102] Alternatively, the disk device 1 may experimentally obtain the timing correction amount for each radial position in advance and store it in the management information storage area. In this case, before S1 in Fig. 9, for a disk device manufactured under standard manufacturing conditions, the processes of S21 to S23 in Fig. 10 are performed and the timing correction data is stored in the management information storage area. In this case, in S2 in Fig. 9, the disk device 1 can obtain the timing correction amount for each radial position by reading the timing correction data from the management information storage area instead of performing learning.

[0103] Alternatively, as a modification of the embodiment, the disk device 1 may write two servo patterns SV in succession in the circumferential direction on a track in the boundary area of ​​zone Z, as shown in FIG.

[0104] For example, in S2 of Fig. 9, a timing correction amount is learned so that two servo patterns SV are continuous in the circumferential direction on the track in the boundary area of ​​zone Z. In this case, in S22 of Fig. 10, for example, ΔG=0 is set in Equation 2, and the RW circumferential offset OF can be converted into the write timing offset RT. Otherwise, the same processing as in the embodiment is performed.

[0105] As a result, in the SSW process, the disk device 1 writes the front servo pattern SV1 and the rear servo pattern SV2 consecutively in the circumferential direction at the radial position TR_n in the zone boundary area, as shown in FIG. 12(a). The disk device 1 writes the front servo pattern SV1 at a write frequency SFG1. The disk device 1 writes the rear servo pattern SV2 at a write frequency SFG2 (>SFG1) from the circumferential end of the front servo pattern SV1. The disk device 1 writes an erase pattern ER12 at the circumferential end of the rear servo pattern SV2.

[0106] In the postcode writing process, the disk device 1 writes postcodes PC1 and PC2 continuously in the circumferential direction at radial position TR_n in the zone boundary area, as shown in FIG. 12(b). The disk device 1 writes multiple postcodes PC1 and PC2 in order by overwriting the erase pattern ER12. An erase pattern ER12a remains at the end of the postcode PC2.

[0107] Thus, in the modified embodiment, in the disk device 1, the controller 130 writes one of the two servo patterns SV in a track in the zone Z boundary area to a position adjacent to the other servo pattern in the circumferential direction in accordance with the timing correction data. This makes it possible to make the circumferential gap ΔG between the two servo patterns SV in the track in the zone Z boundary area approximately zero in each zone boundary area, thereby ensuring a wider area in which data can be recorded, thereby further improving format efficiency.

[0108] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0109] 1 disk device, 10 disk media, 12 heads, 12R read elements, 12W write elements, 130 controller.

Claims

1. Head and a disk medium including a plurality of concentric zones; a controller that, when writing two servo patterns corresponding to two adjacent zones on a track in a boundary area between the two zones by the head, generates timing correction data according to a radial position of the boundary area, writes one of the two servo patterns on the track in the boundary area, and writes the other servo pattern at a position shifted circumferentially from the one servo pattern on the track in the boundary area according to the timing correction data; A disk device comprising:

2. the head includes a read element and a write element, The controller When the write element writes two servo patterns corresponding to the two zones on the track in the boundary area, the timing correction data is generated according to the offset in the circumferential direction of the read element and the write element at the radial position in the boundary area.

2. The disk device according to claim 1.

3. The controller When two servo patterns corresponding to the two zones are written to the track of the boundary area by the write element, the write start timing is corrected according to the timing correction data, and the other servo pattern is written to the track of the boundary area in synchronization with the corrected write start timing.

3. The disk device according to claim 2.

4. The controller When one servo pattern corresponding to the zone is written by the write element to another track other than the track in the boundary area within the zone, the write start timing is corrected so as to approach the write start timing of the track in the boundary area, and the one servo pattern is written to the other track in synchronization with the corrected write start timing.

4. The disk device according to claim 3.

5. The controller A reference zone is determined from among the plurality of zones, and write start timing is corrected so that the write start positional relationship in other zones other than the reference zone among the plurality of zones approaches the circumferential positional relationship of the write start positions set for each zone boundary, and servo patterns are written on tracks in the other zones in synchronization with the corrected write start timing.

4. The disk device according to claim 3.

6. The controller When one servo pattern corresponding to the zone is written by the write element to another track other than the track in the boundary area within the zone, the write start timing is corrected according to the same timing correction data as that of the track in the boundary area, and the one servo pattern is written to the other track in synchronization with the corrected write start timing.

4. The disk device according to claim 3.

7. The controller When one servo pattern corresponding to each of the plurality of zones is written by the write element on each track of the plurality of zones, the timing correction data is generated according to a circumferential offset of the read element and the write element at the radial position, the write start timing is corrected according to the timing correction data, and the one servo pattern is written on the track in synchronization with the corrected write start timing.

4. The disk device according to claim 3.

8. The controller When two servo patterns corresponding to two adjacent zones among the plurality of zones are written by the head on a track in a boundary area between the two zones, one of the two servo patterns is written on the track in the boundary area, an erase pattern is written immediately after the one servo pattern, and the other servo pattern is written from above the erase pattern at a position shifted in the circumferential direction from the one servo pattern on the track in the boundary area according to the timing correction data.

2. The disk device according to claim 1.

9. a disk device having a head and a disk medium including a plurality of concentric zones, generating timing correction data in accordance with a radial position of a boundary area between two adjacent zones of the plurality of zones on the disk medium; writing one of the two servo patterns onto a track in the boundary area; writing the other servo pattern at a position shifted in a circumferential direction from the one servo pattern on the track in the boundary area in accordance with the timing correction data; A method for manufacturing a disk device comprising:

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