JP2009181628A - Write signal phase adjusting device and method for patterned medium, and magnetic disk device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a write signal phase adjusting device which achieves high density recording on a patterned medium by precisely correcting the phase of write signals. <P>SOLUTION: This device adjusting the phase of the write signals to be input to the recording head 404 flying over the magnetic dot lines 110 of a patterned medium 100 to apply magnetic fields has: a means of detecting the phase of the signals 410 obtained by reproducing the first magnetic field of the magnetic dot line 110 by using the reproducing head 402 disposed apart by the fixed distance from the recording head 404, as the first phase; a means of detecting the phase of signals 414 obtained by reproducing the resultant magnetic field, which is obtained by combining the first magnetic field and the second magnetic field for writing by the recording head 404, by using the reproducing head 402, as the second phase; and a means of changing the phase of the write signals based on the phase difference between the first and second phases. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an apparatus and method for adjusting the phase of a write signal to a recording head that floats on a magnetic dot row of a patterned medium and applies a magnetic field, and a magnetic disk apparatus.

  In the magnetic disk device, a small and large-capacity device is continuously demanded, and a high recording density is required. In order to improve the recording density, development of a recording medium in which magnetic dots are artificially arranged regularly, that is, a patterned medium, has been advanced. In patterned media, a high recording density is achieved by recording 1 bit per magnetic dot.

  FIG. 1 is a diagram showing an example of patterned media, FIG. 1A is a diagram showing an overview of a magnetic disk 100 configured as patterned media, and FIG. 1B is a diagram of FIG. FIG. 1C is an enlarged view of a portion 102 in FIG. 1, and FIG. 1C is an enlarged view of the data area 108 in FIG. 1B.

  On the disk 100, a recording track 104 is formed as a pattern in a circumferential shape in advance. The recording track 104 includes a servo area 106 for positioning the recording / reproducing head and a data area 108 for recording data. At least the data area 108 is composed of a row of magnetic dots 110 made of isolated magnetic materials. Yes.

  FIG. 2 is a diagram for explaining the recording and reproduction of data with respect to the patterned medium. FIG. 2A is a diagram showing the waveform of the write magnetic field applied to the magnetic dot 110 row, and FIG. ) Is a diagram showing the top surface of the magnetic dot 110 row, FIG. 2C is a cross-sectional view taken along the section line aa ′ in FIG. 2B, and FIG. 2D is generated from the magnetic dot 110 row. It is a figure which shows the reproduction | regeneration waveform of the magnetic field to perform.

  The magnetic dots 110 are magnetized in the vertical direction, and 1-bit data is recorded depending on whether the direction is upward or downward. Since the positions of the magnetic dots 110 are determined on the disk in advance, when recording data, it is necessary to apply a write magnetic field corresponding to the recording data at the correct recording timing in phase with the magnetic dot row. In particular, the inherent delay of the circuit that generates the write magnetic field and its temperature change also need to be corrected.

  FIG. 8A of Patent Document 1 below describes a method for obtaining an optimum phase by recording with different phases several times or by performing recording with different phases all at once. . Further, FIG. 8B of Patent Document 1 describes a method for finely adjusting the phase after the processing shown in FIG. 8A by utilizing the fact that a weak write magnetic field not recorded on the medium wraps around the reproducing head. Has been.

  Patent Document 1 proposes that a non-magnetic region is provided in a medium, a weak write magnetic field is generated when the head passes through the medium, and a phase difference between the recording circuit and the reproduction circuit is detected and used for write synchronization correction. Has been. However, in order to perform higher density recording, it is desirable that the phase relationship of the write signal can be corrected by directly detecting the phase relationship between the reproduction waveform of the magnetic field generated from the magnetic dots and the write magnetic field.

US Pat. No. 6,738,207

  The present invention has been made in view of the above-described problems, and an object of the present invention is to accurately correct the phase of the write signal in accordance with the inherent delay of the circuit that generates the write magnetic field and the temperature change thereof. Accordingly, it is an object of the present invention to provide a write signal phase adjusting apparatus and method and a magnetic disk apparatus that enable high-density recording on a patterned medium.

  In order to achieve the above object, according to the present invention, there is provided an apparatus for adjusting the phase of a write signal to a recording head that flies over a magnetic dot row of a patterned medium and applies a magnetic field, Means for detecting, as a first phase, a phase of a signal obtained by reproducing a first magnetic field, which is a magnetic field generated from the magnetic dot array, by a reproducing head provided at a certain distance from Means for detecting, as the second phase, a phase of a signal obtained by reproducing with the reproducing head a combined magnetic field of one magnetic field and a second magnetic field that is a write magnetic field from the recording head; And a means for changing the phase of the write signal based on a phase difference between the phase and the second phase.

  In one preferred embodiment, the second magnetic field has a strength that does not reverse the magnetization direction of the magnetic dots.

  In one preferred embodiment, the second magnetic field has a strength that does not saturate the read head.

  In one preferred embodiment, the write signal phase adjusting device further includes means for changing the phase of the write signal based on a distance between the recording head and the reproducing head.

  Furthermore, according to the present invention, there are provided a write signal phase adjusting method having the same technical features as the above-described technical features of the write signal phase adjusting device, and a magnetic disk device including the write signal phase adjusting device. The

  According to the disclosed write signal phase adjusting apparatus and method and magnetic disk apparatus, the phase of the write signal is corrected with high accuracy in accordance with the inherent delay of the circuit that generates the write magnetic field and the temperature change thereof. On the other hand, as a result of the write magnetic field being applied at a timing with high accuracy in phase, high-density recording on the patterned medium becomes possible.

  First, a schematic structure of a magnetic disk device to which an embodiment of a write signal phase adjusting device is applied will be described with reference to FIG. A magnetic disk device is a type of information storage device in which a read head and a head slider mounted with a recording head float on a rotary recording medium to read and write, and FIG. 3 illustrates the internal structure. Therefore, the cover attached from the direction indicated by the arrow A is shown in a removed state.

  In FIG. 3, a patterned medium 100 as a magnetic recording medium (magnetic disk) is fixed to a spindle motor by a clamp 302 and is driven by the spindle motor during operation and continues to rotate at a predetermined rotational speed. The head slider 304 floats on the patterned medium 100 in the order of nm. The reproducing head and recording head mounted on the head slider 304 operate with a predetermined interval with respect to the patterned medium 100.

  The slider 304 is connected to the drive arm 308 via a suspension 306 that applies a constant pressing force to the slider 304. The drive arm 308 is driven by the voice coil motor 310 to scan the patterned medium 100, thereby realizing reading and writing of data at a desired position. These components are attached to the base 312.

  FIG. 4 is a diagram for explaining the principle of the write signal phase adjusting device. In the figure, reference numeral 100 denotes a patterned medium (magnetic disk), reference numeral 110 denotes a magnetic dot, reference numeral 304 denotes a head slider, reference numeral 402 denotes a reproducing head (R head), and reference numeral 404 denotes a recording head (W head). . When there is no write magnetic field from the recording head 404, the output of the reproducing head 402 flying above the magnetic dot 110 row shows a reproduction waveform indicated by reference numeral 410, which reproduces the magnetic field generated from the magnetic dot 110 row.

  Here, consider a case where a magnetic field having a waveform indicated by reference numeral 412 is generated from the recording head 404 as a write magnetic field that is not recorded on the magnetic dots 110 and is not saturated with the reproducing head 402. In this case, since the minute write magnetic field 412 wraps around the reproducing head 402, the reproducing head 402 combines the magnetic field 410 generated from the magnetic dot 110 row and the write magnetic field 412 from the recording head 404. The reproduced waveform indicated by reference numeral 414 is output. In the example shown in FIG. 4, the write magnetic field waveform 412 has a phase lag of 30 ° with respect to the magnetic dot reproduction waveform 410, so that the combined magnetic field reproduction waveform 414 has a phase lag of 15 ° with respect to the magnetic dot reproduction waveform 410. Have.

  As can be seen from FIG. 4, by detecting the reproduction waveform 410 of the magnetic field using only the magnetic dot array and the reproduction waveform 414 of the combined magnetic field using the magnetic field from the magnetic dot array and the write magnetic field from the recording head, A waveform 412 of a write magnetic field that wraps around the reproducing head 402 can be obtained. Therefore, the phase delay of the write magnetic field with respect to the magnetic field due to the magnetic dot row can be known.

  FIG. 5 is a diagram showing an example of a reproduction waveform 410 of a magnetic field generated from a magnetic dot row, a waveform 412 of a write magnetic field from a recording head, and a reproduction waveform 414 of a combined magnetic field of both magnetic fields. 5A, 5B, and 5C show that the phase lag of the write magnetic field waveform 412 from the recording head with respect to the reproduction waveform 410 of the magnetic field generated from the magnetic dot row is 0 °, respectively. , 30 ° and 90 °. Since the phase of the reproduced waveform output changes according to the phase lag of the wraparound waveform of the write magnetic field, the phase lag of the write magnetic field can be obtained conversely, and as a result, the write signal to the recording head that generates the write magnetic field The phase can be adjusted.

  FIG. 6 is a diagram showing a configuration of an embodiment of a write signal phase adjusting device. In the figure, reference numeral 602 indicates a phase detector, reference numeral 604 indicates a controller, reference numeral 606 indicates a write signal generator, and reference numeral 608 indicates a head amplifier. The phase detector 602 receives the output of the reproducing head 402, detects the phase, and sends it to the controller 604. The controller 604 controls the phase of the write signal generated by the write signal generator 606 based on the detected phase. The write signal generated by the write signal generator 606 is amplified by the head amplifier 608 and sent to the recording head 404 to generate a write magnetic field.

FIG. 7 is a diagram showing an operation flow of the write signal phase adjusting device shown in FIG. First, the disk (patterned medium) 100 rotates at a predetermined rotational speed, the head slider 304 flies over the magnetic dot 110 row at a predetermined relative speed, and a write magnetic field from the recording head 404 is generated. In the absence, the reproducing head 402 reproduces the magnetic field (first magnetic field) generated from the magnetic dot 110 row. The phase detector 602 detects the phase Φ _R of the signal waveform of the first magnetic field reproduced by the reproducing head 402 and sends information on the phase Φ _R to the controller 604 (step 702). In the example of the magnetic dot reproduction waveform 410 shown in FIG. 5B, 0 ° is detected as the phase Φ _R.

Next, the controller 604 controls the write signal generator 606 so as to generate a write signal for generating a minute write magnetic field at the phase Φ _R. This write signal is amplified by the head amplifier 608 and sent to the recording head 404. Then, the recording head 404 generates a minute write magnetic field (second magnetic field) (step 704). The write magnetic field has a strength that does not reverse the magnetization direction of the magnetic dots and does not saturate the reproducing head 402.

Then, the reproducing head 402 reproduces a combined magnetic field of a magnetic field (first magnetic field) generated from the magnetic dot 110 row and a write magnetic field (second magnetic field) that goes around from the recording head 404. The phase detector 602 detects the phase Φ _{R + W} of the signal waveform of the combined magnetic field reproduced by the reproducing head 402 and sends information on the phase Φ _{R + W} to the controller 604 (step 706). In the example of the synthetic magnetic field reproduction waveform 414 shown in FIG. 5B, 15 ° is detected as the phase Φ _{R + W.}

Next, the controller 604 determines the phase of the generation of the write signal.
(Φ _{R + W} −Φ _R ) × 2
Control is performed to advance only by (step 708). Thereby, the phase of the write magnetic field can be matched with the magnetic dot reproduction waveform. In the example shown in FIG. 5B, since the phase Φ _R of the magnetic dot reproduction waveform 410 is 0 ° and the phase Φ _{R + W} of the combined magnetic field reproduction waveform 414 is 15 °, (15 ° -0 ° ) × 2 = 30 °, the phase of the write signal is advanced, and the phase delay 30 ° of the write magnetic field waveform 412 is eliminated. Thus, the intrinsic delay of the circuit that generates the write magnetic field and its temperature change can be corrected with high accuracy.

  In actual data recording, it is necessary to separately correct the phase γ corresponding to the distance d between the recording head 404 and the reproducing head 402. In the example shown in FIG. 6, the slider 304 travels in the direction of the arrow 610 with respect to the disk 100, and the recording head 404 is positioned behind the reproducing head 402. It is necessary to delay by the phase γ corresponding to d. Therefore, the controller 604 executes control to perform actual data recording by further delaying the phase of the write signal generation by the phase γ (step 710).

  Regarding the above embodiment, the following supplementary notes are disclosed.

(Appendix 1) A device that adjusts the phase of a write signal to a recording head that floats on a magnetic dot array of a patterned medium and applies a magnetic field,
Means for detecting, as a first phase, a phase of a signal obtained by reproducing a first magnetic field, which is a magnetic field generated from the magnetic dot array, by a reproducing head provided at a certain distance from the recording head; ,
Means for detecting, as a second phase, a phase of a signal obtained by reproducing with the reproducing head a combined magnetic field of the first magnetic field and a second magnetic field that is a write magnetic field from the recording head;
Means for changing the phase of the write signal based on a phase difference between the first phase and the second phase;
A write signal phase adjusting device comprising:

  (Supplementary note 2) The write signal phase adjusting device according to supplementary note 1, wherein the second magnetic field has a strength that does not reverse the magnetization direction of the magnetic dots.

  (Supplementary note 3) The write signal phase adjusting device according to supplementary note 1, wherein the second magnetic field has an intensity that does not saturate the reproducing head.

  (Supplementary note 4) The write signal phase adjusting device according to supplementary note 1, further comprising means for changing a phase of the write signal based on a distance between the recording head and the reproducing head.

(Supplementary Note 5) A method for adjusting the phase of a write signal to a recording head that floats on a magnetic dot row of a patterned medium and applies a magnetic field,
Detecting a phase of a signal obtained by reproducing a first magnetic field, which is a magnetic field generated from the magnetic dot array, by a reproducing head provided at a certain distance from the recording head as a first phase; ,
Detecting a phase of a signal obtained by reproducing a combined magnetic field of the first magnetic field and a second magnetic field, which is a write magnetic field from the recording head, by the reproducing head as a second phase;
Changing the phase of the write signal based on the phase difference between the first phase and the second phase;
Write signal phase adjustment method comprising:

  (Supplementary note 6) The write signal phase adjustment method according to supplementary note 5, wherein the second magnetic field has a strength that does not reverse the magnetization direction of the magnetic dots.

  (Supplementary note 7) The write signal phase adjustment method according to supplementary note 5, wherein the second magnetic field has an intensity that does not saturate the reproducing head.

  (Supplementary note 8) The write signal phase adjustment method according to supplementary note 5, further comprising a step of changing a phase of the write signal based on a distance between the recording head and the reproducing head.

  (Supplementary note 9) A magnetic disk device including the write signal phase adjusting device according to any one of supplementary notes 1 to 4.

It is a figure which shows the example of patterned media. It is a figure for demonstrating recording and reproduction | regeneration of the data with respect to a patterned media. 1 is a diagram illustrating a schematic structure of a magnetic disk device to which an embodiment of a write signal phase adjusting device is applied. It is a figure for demonstrating the principle of a write signal phase adjustment apparatus. It is a figure which shows the reproduction waveform of the magnetic field which generate | occur | produces from a magnetic dot row | line | column, the waveform of the write magnetic field from a recording head, and the reproduction waveform of the synthetic magnetic field of both magnetic fields. It is a figure which shows the structure of one Embodiment of a write signal phase adjustment apparatus. It is a figure which shows the operation | movement flow of the write signal phase adjustment apparatus shown by FIG.

Explanation of symbols

100 patterned media (disc)
104 Recording Track 106 Servo Area 108 Data Area 110 Magnetic Dot 302 Clamp 304 Head Slider 306 Suspension 308 Drive Arm 310 Voice Coil Motor 312 Base 402 Playback Head 404 Recording Head 602 Phase Detector 604 Controller 606 Write Signal Generator 608 Head Amplifier

Claims (7)

A device that adjusts the phase of a write signal to a recording head that levitates and travels over a magnetic dot array of patterned media and applies a magnetic field,
Means for detecting, as a first phase, a phase of a signal obtained by reproducing a first magnetic field, which is a magnetic field generated from the magnetic dot array, by a reproducing head provided at a certain distance from the recording head; ,
Means for detecting, as a second phase, a phase of a signal obtained by reproducing with the reproducing head a combined magnetic field of the first magnetic field and a second magnetic field that is a write magnetic field from the recording head;
Means for changing the phase of the write signal based on a phase difference between the first phase and the second phase;
A write signal phase adjusting device comprising:   The write signal phase adjusting device according to claim 1, wherein the second magnetic field has a strength that does not reverse the magnetization direction of the magnetic dots.   The write signal phase adjusting device according to claim 1, wherein the second magnetic field has a strength that does not saturate the reproducing head.   The write signal phase adjusting apparatus according to claim 1, further comprising means for changing a phase of the write signal based on a distance between the recording head and the reproducing head. A method of adjusting a phase of a write signal to a recording head that applies a magnetic field by flying over a magnetic dot row of a patterned medium,
Detecting a phase of a signal obtained by reproducing a first magnetic field, which is a magnetic field generated from the magnetic dot array, by a reproducing head provided at a certain distance from the recording head as a first phase; ,
Detecting a phase of a signal obtained by reproducing a combined magnetic field of the first magnetic field and a second magnetic field, which is a write magnetic field from the recording head, by the reproducing head as a second phase;
Changing the phase of the write signal based on the phase difference between the first phase and the second phase;
Write signal phase adjustment method comprising:   6. The write signal phase adjustment method according to claim 5, further comprising a step of changing a phase of the write signal based on a distance between the recording head and the reproducing head.   A magnetic disk device comprising the write signal phase adjusting device according to any one of claims 1 to 4.

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