Magnetic recording and playback device, and method for adjusting the same.

Abstract

To provide a magnetic recording / reproducing device and a method of adjusting the same for determining a flying height change of a thermally assisted magnetic recording head.SOLUTION: A method of adjusting a magnetic recording / reproducing device according to the embodiment is a method of adjusting a magnetic recording / reproducing device having a thermally assisted magnetic recording head and a magnetic disk, and includes: performing a first write operation at a first position on a recording surface; measuring a first error rate at a second position having a different radial directional position from the first position; measuring a second error rate after performing a second write operation; obtaining a first difference between the first error rate and the second error rate; measuring a third error rate at the first position; measuring a fourth error rate after performing a third write operation; obtaining a second difference between the third error rate and the fourth error rate; and determining a flying height change by comparing the first difference and the second difference.SELECTED DRAWING: Figure 1

Description

[[Technical Field]]

[0001] Embodiments of the present invention relate to a magnetic recording / reproducing apparatus and an adjustment method thereof. [[Background Art]]

[0002] In a heat-assisted magnetic recording head, recording is performed by increasing the temperature of a magnetic disk with a laser. At this time, it is known that due to the temperature increase, components believed to originate from the magnetic film of the magnetic disk adhere to the tip of a near-field optical element (NFT) via a lubricant, forming a cured product. The generation of cured lubricant is unavoidable due to the principle of recording. On the other hand, it is known that when the cured lubricant adheres, it increases the laser transmittance and functions as a layer that improves the laser transmission efficiency.

[0003] The cured lubricant is scraped off by abrasion when the flying height is reduced, and is re-formed when the flying height is increased by lubricant filling between the head and the medium. Therefore, when the flying height fluctuates within the disk surface, for example, when the head moves from a track with a low flying height to a track with a high flying height, there arises a problem that writing performance degrades until the cured lubricant is generated. Further, conventionally, regarding the flying height adjustment of a write head and an NFT, the adjustment accuracy of the flying height has been inferior to that of a read head. For this reason, it is desired to adjust the flying height of the write head such that no difference in error rate occurs between immediately after seeking and after sufficient writing. Furthermore, it is similarly desired to adjust the flying height when the temperature changes, and also for flying height monitoring at a user site. [[Prior Art Literature]] [[Patent Literature]]

[0004] [[Patent Literature 1]] US Patent Application Publication No. 2017 / 0221511 Specification [[Patent Literature 2]] US Patent No. 10410660 Specification [Patent Document 3] Japanese Patent Publication No. 2022-173700 [Patent Document 4] U.S. Patent No. 11735217 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] The embodiments of the present invention aim to determine the change in the amount of levitation of a heat-assisted magnetic recording head. [Means for solving the problem]

[0006] According to one embodiment, this is a method for adjusting a magnetic recording and playback apparatus equipped with a heat-assisted magnetic recording head and a magnetic disk, At a first position on the recording surface of the magnetic disk, the heat-assisted magnetic recording head performs a first write operation. The heat-assisted magnetic recording head is sought to a second position on the recording surface that is radially different from the first position, and the first error rate is measured. After performing the second light operation at the second position, the second error rate is measured. The first difference between the first error rate and the second error rate is calculated, The heat-assisted magnetic recording head is sought to the first position to measure the third error rate. After performing the third light operation at the first position, the fourth error rate is measured. The second difference between the third error rate and the fourth error rate is calculated. A method for adjusting a magnetic recording and playback device is provided, which includes comparing the first difference and the second difference to determine the change in the amount of levitation. [Brief explanation of the drawing]

[0007] [Figure 1] This is a block diagram showing the configuration of an example of a magnetic recording and playback device according to the second embodiment. [Figure 2] This is a partial exploded perspective view of a magnetic recording and playback device according to the second embodiment. [Figure 3] This is a side view showing the magnetic head and suspension. [Figure 4] This is a partial cross-sectional view of a magnetic recording and playback device according to the second embodiment. [Figure 5] This is a flowchart illustrating an example of an adjustment method for a magnetic recording and playback device according to the first embodiment. [Figure 6] This block diagram shows another example of the MPU in Figure 5. [Figure 7] This flowchart shows another example of an adjustment method for a magnetic recording and playback device according to the first embodiment. [Figure 8] This flowchart shows another example of an adjustment method for a magnetic recording and playback device according to the first embodiment. [Figure 9] This flowchart shows another example of an adjustment method for a magnetic recording and playback device according to the first embodiment. [Figure 10] This is a block diagram showing the configuration of another example of a magnetic recording and playback device according to the second embodiment. [Figure 11] This is a block diagram showing the configuration of another example of a magnetic recording and playback device according to the second embodiment. [Figure 12] This is a block diagram showing the configuration of another example of a magnetic recording and playback device according to the second embodiment. [Modes for carrying out the invention]

[0008] The adjustment method for a magnetic recording and playback apparatus according to the first embodiment is an adjustment method for a magnetic recording and playback apparatus equipped with a heat-assisted magnetic recording head and a magnetic disk, At a first position on the recording surface of the magnetic disk, the heat-assisted magnetic recording head performs a first write operation. The heat-assisted magnetic recording head is sought to a second position on the recording surface, which is radially different from the first position, and the first error rate is measured. After performing the second light operation at the second position, the second error rate is measured. We calculate the first difference between the first error rate and the second error rate. Seeking a heat-assisted magnetic recording head to a first position, measuring a third error rate, after performing a third write operation at the first position, measuring a fourth error rate, obtaining a second difference between the third error rate and the fourth error rate, comprising comparing the first difference and the second difference to determine a change in flying height.

[0009] A magnetic recording and reproducing apparatus according to a second embodiment is an example of an apparatus for implementing the adjustment method for the magnetic recording and reproducing apparatus according to the first embodiment, wherein a magnetic disk comprising a magnetic recording layer and a lubricant provided on a recording surface of the magnetic recording layer, a heat-assisted magnetic recording head that performs magnetic recording on the magnetic disk, a head position control unit that disposes the heat-assisted magnetic recording head at a first position on the recording surface or a second position having a radial position different from that of the first position, a write operation control unit that respectively controls a first write operation at the first position, a second write operation at the second position, and a third write operation at the first position, an error rate measuring unit that measures a first error rate before the second write operation, a second error rate after the second write operation, a third error rate before the third write operation, and a fourth error rate after the third write operation, an arithmetic unit that respectively obtains a first difference between the first error rate and the second error rate, and a second difference between the third error rate and the fourth error rate, comprising a determination unit that compares the first difference and the second difference to determine a change in flying height.

[0010] According to the first embodiment and the second embodiment, a change in the flying height of the heat-assisted magnetic recording head can be determined by obtaining and comparing differences between error rates before and after a write operation at two or more positions having different radial positions. Further, it becomes possible to adjust the flying height of the heat-assisted magnetic recording head based on the obtained difference and the determined change in flying height.

[0011] Example Example 1 The embodiments will be described below with reference to the drawings. Furthermore, the disclosure is merely an example, and any modifications that can be easily conceived by a person skilled in the art while maintaining the spirit of the invention are naturally included within the scope of the present invention. In addition, the drawings may schematically represent the width, thickness, shape, etc. of each part in order to clarify the explanation, but these are merely examples and do not limit the interpretation of the present invention. In addition, in this specification and each drawing, elements similar to those described above in previously shown drawings are denoted by the same reference numerals, and detailed explanations may be omitted as appropriate.

[0012] First, with reference to Figure 1, an example configuration of a disk drive according to the second embodiment will be described. Note that the configuration of the disk drive, which is a magnetic recording and playback device, shown in Figure 1 will also apply to each embodiment described later. As shown in Figure 1, the disk drive 200 is a magnetic disk device using a perpendicular magnetic recording method, incorporating a magnetic disk 1 which is a perpendicular magnetic recording medium, and a magnetic head 10 having a magnetic flux control layer, which will be described later.

[0013] Figure 2 is a partial exploded perspective view of a magnetic recording and playback apparatus according to the second embodiment. Figure 2 shows a magnetic recording and playback apparatus according to the second embodiment, in which a plurality of magnetic disks 1 and a plurality of magnetic heads 10 are housed within a housing 51, with the lid omitted. The magnetic disk 1 is fixed to a spindle motor (SPM) 2 and mounted to rotate. The magnetic head 10 is mounted on an actuator 3 and configured to move radially on the magnetic disk 1. The actuator 3 is rotationally driven by a voice coil motor (VCM) 4. In Figure 1, for example, the magnetic head 10 is shown seeking to a first position on the recording surface 1a, and the magnetic head 10' mounted on actuator 3' is shown seeking to a second position, which is radially different from the first position. The magnetic head 10 includes a write head 10W, a read head 10R, and a heat assist unit 100. The write head 10W writes data to the magnetic disk 1. The read head 10R reads data from the magnetic disk 1. The heat assist unit 100 assists the write head 10W when writing data to the magnetic disk 1. The magnetic head 10 may include one or more magnetic heads.

[0014] Furthermore, the disk drive includes a head amplifier integrated circuit (hereinafter referred to as head amplifier IC) 11, a read / write channel (R / W channel) 12, a hard disk controller (HDC) 13, a microprocessor (MPU) 14-1, a driver IC 16, and memory 17. The R / W channel 12, HDC 13, and MPU 14 are incorporated into a controller 15 which is a single-chip integrated circuit. The head amplifier IC11 includes a set of circuits for driving a laser diode for thermal assistance, as described later. Furthermore, the head amplifier IC11 includes a driver that supplies a recording signal (write current) to the recording head 10W in accordance with the write data supplied from the R / W channel 12. The head amplifier IC11 also includes a read amplifier that amplifies the read signal output from the playback head 10R and transmits it to the R / W channel 12.

[0015] The R / W channel 12 is a signal processing circuit for read / write data. The HDC 13 forms the interface between the disk drive and the host 18 and performs read / write data transfer control. The MPU 14 is the main control unit of the disk drive and performs servo control necessary for controlling read / write operations and positioning the magnetic head 10. Furthermore, the MPU 14 includes a head position control unit 19 that positions the heat-assisted magnetic recording head 10 at a first position on the recording surface or at a second position radially different from the first position; a write operation control unit 61 that controls the first write operation at the first position, the second write operation at the second position, and the third write operation at the first position, respectively; an error rate measurement unit 62 that measures the first error rate before the second write operation, the second error rate after the second write operation, the third error rate before the third write operation, and the fourth error rate after the third write operation; a calculation unit 63 that calculates the first difference between the first and second error rates and the second difference between the third and fourth error rates, respectively; and a determination unit 64 that compares the first and second differences and determines the change in the amount of floating. Memory 17 includes a buffer memory and flash memory, which are made up of DRAM. The temperature sensor 9-1 can be installed in the empty space on the bottom wall 52a of the base 52, for example, between the board unit (FPC unit) 53 on which electronic components such as a conversion connector are mounted and the magnetic disk 1, and can be installed as needed.

[0016] Figure 3 is a side view showing the magnetic head 10 and suspension. As shown in Figure 3, each magnetic head 10 is configured as a levitation head and has a substantially rectangular slider 42 and a recording / playback head section 44 provided at the trailing end of the slider 42. The magnetic head 10 is fixed to a gimbal spring 41 provided at the tip of a suspension 34. A head load L toward the surface of the magnetic disk 1 is applied to each magnetic head 10 by the elasticity of the suspension 34. As shown in Figure 2, each magnetic head 10 is connected to a head amplifier IC 11 and an HDC 13 via a wiring member (flexi-sha) 35 fixed on the suspension 34 and arm.

[0017] Next, the configuration of the magnetic disk 1 and the magnetic head 10 will be described in detail. Figure 4 is a cross-sectional view of the write head 10W and magnetic disk 1, which are part of the magnetic disk drive. The magnetic disk 1 has a substrate 20 and, sequentially stacked on the substrate 20, a heat sink layer 21, a crystal orientation layer 22, a vertical recording layer 23, and a protective film 24 with a lubricant applied to its surface. The vertical recording layer 23 has a large anisotropy in the direction perpendicular to the disk surface. The crystal orientation layer 22 is placed below the vertical recording layer 23 to improve its orientation. The heat sink layer 21 is placed below the crystal orientation layer 22 to suppress the spread of the heated area. The protective film 24 is placed on top of the vertical recording layer 23 and protects the vertical recording layer 23.

[0018] The magnetic head 10 is a separated magnetic head in which the recording head 10W and the playback head 10R are separated. The recording head 10W consists of a main magnetic pole 40 made of a high-permeability material that generates a magnetic field perpendicular to the disk surface, a trailing yoke 50 magnetically connected to the main magnetic pole 40 that conducts magnetic flux through the main magnetic pole 40, a return shield magnetic pole 60 located on the reading side of the main magnetic pole 40 to efficiently close the magnetic path directly beneath the main magnetic pole, a coil 70 arranged to wrap around the magnetic path including the trailing yoke and the return shield magnetic pole to conduct magnetic flux through the main magnetic pole 40, a heater 80 for controlling the levitation height of the recording head, a near-field optical element 30 located on the reading side of the main magnetic pole 40 that generates near-field light to heat the vertical recording layer 23 of the magnetic disk 1, and a waveguide 31 for propagating the light for generating near-field light. The light source is a laser diode 32 mounted on the slider of the actuator assembly 3. As the near-field optical element 30, for example, an alloy consisting of Au, Pd, Pt, Rh, or Ir, or several combinations thereof, can be used. As the insulating layer provided between the main magnetic pole and the near-field optical element, for example, an oxide consisting of SiO2, Al2O3, etc., can be used.

[0019] Examples of heat-assisted magnetic recording methods usable in the magnetic disk drive 200 include the conventional recording method, known as CMR (Conventional Magnetic Recording), in which tracks are written with radial spacing so that adjacent tracks do not overlap; the shingled magnetic recording method, known as SMR (Shingled Magnetic Recording), which has tracks stacked sequentially in the radial direction and records by overlapping parts of adjacent tracks; the interlaced magnetic recording method, known as IMR (Interlaced Magnetic Recording), which has a bottom track and a top track with adjacent tracks stacked alternately, and records on the bottom track after recording on the bottom track by overlapping the interlaced top track; or combinations thereof.

[0020] Figure 5 shows a flowchart illustrating an example of an adjustment method using the magnetic recording and playback apparatus according to the first embodiment shown in Figure 1. Example 1 shows an example of an adjustment method using the magnetic recording and playback device according to the first embodiment, which compares the amount of levitation between two positions with different radial positions. As shown in the figure, the adjustment method for the magnetic recording and playback device is started. First, at a first position on the recording surface of the magnetic disk, the heat-assisted magnetic recording head 10 is controlled by the write operation control unit 61 to perform a first write operation (ST1) and form a lubricant hardened product. Next, the head position control unit 19 controls the heat-assisted magnetic recording head 10 to seek to a second position, which is radially different from the first position on the recording surface, and the error rate measurement unit 62 measures the first error rate (ST2). Subsequently, the write operation control unit 61 controls the heat-assisted magnetic recording head to perform a second write operation at the second position (ST3) and form a lubricant hardened product. After that, the error rate measurement unit 62 measures the second error rate at the second position (ST4), and the calculation unit 63 calculates the first difference between the first error rate and the second error rate (ST5). Subsequently, the head position control unit 19 controls the heat-assisted magnetic recording head 10 to seek to the first position, and the error rate measurement unit 62 measures the third error rate (ST6). Subsequently, the light operation control unit 61 controls the heat-assisted magnetic recording head 10 to perform a third light operation at the first position (ST7) to form a lubricant hardened material. Then, the error rate measurement unit 62 measures the fourth error rate at the first position (ST8), and the calculation unit 63 calculates the second difference between the third error rate and the fourth error rate (ST9). Next, the determination unit 64 compares the first difference and the second difference to determine the change in levitation amount (ST10), and the process ends. This allows for a comparison of levitation between two different positions.

[0021] The lower of the absolute values ​​of the first difference and the second difference can be used to determine that the outflow is lower. The radial position, as used here, can be determined by the distance from the center of the recording surface 1a of the magnetic disk 1. For example, a second position having a different radial position from the first position means that, when the first position is in a concentric circle having a first distance from the center of the recording surface 1a of the magnetic disk 1, the second position lies in a concentric circle having a second distance from the center of the recording surface 1a that is different from the first distance.

[0022] Furthermore, the first, second, and third write operations can be performed continuously for a predetermined time, such as a sufficient time to form a hardened lubricant. The predetermined time for each write operation can be determined by the time it takes for the difference in error rates to disappear. For example, it can be set to 1 to 3 seconds. The predetermined time can be set to be the same for the first, second, and third write operations, for example. In measuring error rates such as the first error rate, second error rate, third error rate, and fourth error rate, data for measuring the error rate can be written and played back.

[0023] According to the embodiment, by measuring the error rate before and after the writing operation at two or more positions with different radial positions on the recording surface 1a, and calculating and comparing the difference, it becomes possible to determine the change in the amount of floating due to the formation of lubricant hardened material. If there is a change in the amount of floating, it is possible to determine which amount of floating to use as the reference.

[0024] For example, it is possible to determine the change in the amount of levitation at three positions with different radial positions. In this case, in the adjustment method of the magnetic recording and playback apparatus according to the first embodiment, after determining the second difference, the head position control unit 19 controls the heat-assisted magnetic recording head 10 to seek to a third position which has a different radial position from the first and second positions, and the error rate measurement unit 62 measures the fifth error rate. Subsequently, the write operation control unit 61 controls the heat-assisted magnetic recording head 10 to perform a fourth write operation at the third position, and then the error rate measurement unit 62 measures the sixth error rate. After that, the calculation unit 63 determines the third difference between the fifth error rate and the sixth error rate, and the determination unit 64 compares the first difference, the second difference and the third difference to determine the change in the amount of levitation. Furthermore, the amount of levitation can be adjusted so that there is no difference in error rate at two or more positions with different radial positions. This makes it possible to equalize the height of the lubricant curing material at two or more positions with different radial positions.

[0025] In the adjustment method for the magnetic recording and playback device according to the first embodiment, a write operation can be performed again at any time, the error rate before and after the operation can be measured, and the difference in the error rates can be calculated and compared for evaluation. These timings can be freely set, for example, before shipment after manufacturing, after shipment, at regular intervals, when the temperature changes, or when the humidity changes. Furthermore, if necessary, the levitation amount change can be monitored after shipment, for example at the user's site, by measuring the error rate before and after the write operation, calculating the difference, and comparing them. In addition, it is possible to arbitrarily adjust the levitation amount in accordance with the change in levitation amount. This monitoring of levitation amount changes can be performed in the background when the magnetic recording and playback device 200 is not performing recording and playback operations. The user area on the recording surface can be used as the location for the write operation, or a test cylinder can be provided for testing purposes. Furthermore, if a change in the amount of ascent is detected, the host 18 can be notified. In this case, the host 18 can be notified using the SMART (Self-Monitoring Analysis and Reporting Technology) function.

[0026] The magnetic disk 1 included in the magnetic recording and playback apparatus 200 according to this embodiment can use a perpendicular magnetic recording medium. The perpendicular magnetic recording medium can include, for example, a magnetic recording layer with a granular structure. The magnetic recording layer with a granular structure includes magnetic particles having an L10 structure as a magnetic material. Examples of magnetic particles having an L10 structure include FePt alloy particles and CoPt alloy particles. As grain boundaries, the grain boundary material can include C, BN, and oxides containing SiO2. The lubricant hardened product is thought to be a hardened product formed when components derived from the magnetic recording layer, such as SiO2 contained in the grain boundaries, adhere to the NFT tip via the lubricant. A protective layer can also be provided on the magnetic recording layer. For example, carbon (C), diamond-like carbon, SiO2, and ZrO2 can be used as the protective layer. For example, perfluoropolyether, fluorinated alcohol, and fluorinated carboxylic acid can be used as a lubricant applied to the recording surface of the magnetic disk.

[0027] Example 2 Example 2 shows another example of the adjustment method for the magnetic recording and playback apparatus according to the first embodiment, in which the amount of levitation is adjusted based on the determination result of the change in the amount of levitation. Figure 6 shows an example of an MPU used in another example of a magnetic recording and playback apparatus according to the second embodiment. MPU14-2 has the same configuration as MPU14-1 in Figure 1, except that it further includes a levitation amount adjustment unit 65. The magnetic recording and playback device used in Example 2 is another example of the magnetic recording and playback device according to the second embodiment, and has the same configuration as in Figure 1, except that MPU14-2 in Figure 6 is used instead of MPU14-1.

[0028] Figure 7 shows a flowchart illustrating another example of the adjustment method for the magnetic recording and playback apparatus according to the first embodiment. As shown in the figure, the adjustment of the magnetic recording and playback device is started. First, at a first position on the recording surface 1a of the magnetic disk 1, the write operation control unit 61 controls the heat-assisted magnetic recording head 10 to perform a first write operation (ST11) to form a lubricant hardened substance. Next, the head position control unit 19 controls the heat-assisted magnetic recording head 10 to seek to a second position on the recording surface 1a that is radially different from the first position, and the error rate measurement unit 62 measures the first error rate (ST12). Subsequently, the write operation control unit 61 controls the heat-assisted magnetic recording head to perform a second write operation at the second position (ST13) to form a lubricant hardened substance. After that, the error rate measurement unit 62 measures the second error rate at the second position (ST14), and the calculation unit 63 calculates the first difference between the first error rate and the second error rate (ST15). Next, the head position control unit 19 controls the heat-assisted magnetic recording head 10 to seek to the first position, and the error rate measurement unit 62 measures the third error rate (ST16). After that, the write operation control unit 61 controls the heat-assisted magnetic recording head 10 to perform a third write operation at the first position (ST17) to form a lubricant hardened product. After that, the error rate measurement unit 62 measures the fourth error rate at the first position (ST18), and the calculation unit 63 calculates the second difference between the third error rate and the fourth error rate (ST19). Steps ST11 to ST19 are the same as steps ST1 to ST9 of the adjustment method in Embodiment 1.

[0029] Next, the determination unit 64 compares the first difference and the second difference to determine if there is a change in the amount of buoyancy (ST20). If the determination shows a change in the amount of buoyancy, the buoyancy adjustment unit 65 adjusts the amount of buoyancy (ST21), and then the process from ST11 to ST20 is repeated. On the other hand, if there is no change in the amount of buoyancy, the process ends. This makes it possible to compare and adjust the amount of buoyancy at two different positions. Furthermore, if the amount of buoyancy changes, for example, the lower of the absolute values ​​of the first and second differences can be determined as the reference radial position. In adjusting the amount of buoyancy, the amount of buoyancy can be reduced until the difference in error rates at radial positions other than the reference radial position is the same as the difference in error rates at the reference radial position. This makes it possible to equalize the height of the lubricant curing material at two positions.

[0030] Example 3 Example 3 shows another example of the adjustment method for the magnetic recording and playback apparatus according to the first embodiment, in which the change in levitation amount is determined at three positions with different radial positions. Figure 8 is a flowchart illustrating yet another example of the adjustment method for the magnetic recording and playback apparatus according to the first embodiment. Here, a magnetic recording and playback device similar to that in Example 2 can be used. As shown in the figure, first, the magnetic recording and playback device is adjusted, and the first and second differences are determined using ST31 to ST39 in the same manner as ST11 to ST19 in Example 2.

[0031] Next, the head position control unit 19 controls the heat-assisted magnetic recording head 10 to seek to a third position which is radially different from the first and second positions, and the error rate measurement unit 62 measures the fifth error rate (ST40). The write operation control unit 61 controls the heat-assisted magnetic recording head 10 to perform a fourth write operation at the third position (ST41). After that, the error rate measurement unit 62 measures the sixth error rate (ST42). The calculation unit 63 calculates the third difference between the fifth error rate and the sixth error rate (ST43). The determination unit 64 compares the first difference, the second difference, and the third difference to determine the change in the amount of levitation (ST44). The error rate measurement unit 62 measures the fifth error rate before the fourth write operation and the sixth error rate after the fourth write operation.

[0032] Furthermore, if necessary, the levitation amount is adjusted by the levitation amount adjustment unit 65 if there is a change in the levitation amount (ST45), and then the process from ST31 to ST43 is repeated. On the other hand, if the levitation amount does not change, the process can be terminated. This allows for comparison and adjustment of the levitation amounts between three different positions. In Figure 8, after ST44, the levitation amount is adjusted in ST45 as necessary, but it is also possible to terminate the adjustment method of the magnetic recording and playback device by only performing the determination in ST44.

[0033] If the amount of buoyancy changes, for example, the lowest absolute value of the third difference between the absolute values ​​of the first and second differences can be determined as the reference radial position. In adjusting the amount of buoyancy, the amount of buoyancy can be reduced until the difference in error rates at radial positions other than the reference radial position is the same as the difference in error rates at the reference radial position. This makes it possible to equalize the height of the lubricant curing material at the three positions.

[0034] Example 4 Example 4 shows yet another example of the adjustment method for the magnetic recording and playback apparatus according to the first embodiment, in which the change in levitation amount is monitored in the background. Figure 9 is a flowchart illustrating yet another example of the adjustment method for the magnetic recording and playback apparatus according to the first embodiment. Here, a magnetic recording and playback device similar to that in Example 2 can be used. First, prepare a magnetic recording and playback device in which the first and second differences are determined in the same manner as in Example 2, a comparison of the levitation amounts between the two positions is performed, and the levitation amount is adjusted as necessary.

[0035] After performing a light operation in the user area, the system confirms that the heat-assisted magnetic recording head can operate in the background and begins monitoring changes in the levitation level. "Operating in the background" refers to a state where the system can operate without being visible to the user, such as during idle time. First, the head position control unit 19 controls the heat-assisted magnetic recording head 10 and seeks it to a fourth position, which is radially different from the first and second positions, for example, one position on a test cylinder, and measures the sixth error rate (ST51). Next, the write operation control unit 61 controls the heat-assisted magnetic recording head 10 to perform a fifth write operation at the fourth position (ST52) and form a lubricant hardened product. After that, the error rate measurement unit 62 measures the seventh error rate at the fourth position (ST53). That is, the error rate measurement unit 62 measures the sixth error rate before the fifth write operation and the seventh error rate after the fifth write operation. Next, the calculation unit 63 calculates the fourth difference between the seventh error rate and the sixth error rate (ST54).

[0036] Next, the determination unit 64 compares the fourth difference with the previously determined first difference and / or second difference to determine if there is a change in the amount of buoyancy (ST55). If there is a change in the amount of ascent, check if the fourth difference is a negative value (ST56). If the fourth difference is a negative value, terminate the monitor abnormally. If the fourth difference is not a negative value, adjust the amount of ascent (ST57). Then, repeat ST51 to 55. If there is no change in the amount of ascent, the monitoring of the amount of ascent is terminated. In Figure 9, after ST55, ST56 is determined, and if necessary, the amount of ascent is adjusted in ST57. However, it is possible to terminate the monitoring of the amount of ascent after only determining ST55.

[0037] For example, the host 18 can be optionally notified when a change in the amount of buoyancy is detected, when the monitor terminates abnormally, or when the monitor is terminated. The SMART function can be used in this case. This makes it possible to automatically monitor changes in the levitation level of the magnetic recording / playback device in the background, invisible to the user, at any time before or after shipment. In the explanation of Figure 9, an example was given in which the fourth position differs radially from the first and second positions. However, it is also possible to use either the first or second position as the fourth position.

[0038] Example 5 Example 5 shows an example where further comparison and evaluation are performed when the temperature changes. Figure 10 shows a block diagram illustrating yet another example of the configuration of a magnetic recording and playback device according to the second embodiment. As shown in the figure, the magnetic recording and playback device 201 is a magnetic recording and playback device used in Embodiment 5, and has the same configuration as in Figure 1, except that a temperature sensor 9-1 is further connected to the MPU 14-1. As shown in Figure 2, the temperature sensor 9-1 is installed at any location within the magnetic disk drive to detect the ambient temperature of the device.

[0039] In Example 5, for example, instead of starting to monitor the change in buoyancy amount at a timing that allows for background operation, the comparison and determination of the change in buoyancy amount is started at the timing when it is determined that there is a temperature change based on the temperature information from the temperature sensor 9-1. In the same manner as in Example 4, the change in buoyancy amount between two or more positions with different radial positions can be determined by the steps ST51 to ST57 in Figure 9. Temperature information from temperature sensor 9-1 can be set to be acquired at regular intervals. The temperature difference between the acquired temperature data can be calculated by the calculation unit 63. Based on the temperature difference, the determination unit 64 can determine that there is a temperature change.

[0040] Example 6 Example 6 shows an example where further comparison and evaluation are performed when the humidity changes. Figure 11 shows a block diagram illustrating yet another example of the configuration of a magnetic recording and reproducing apparatus according to the second embodiment. As shown in Figure 11, the magnetic recording and playback device 202 has the same configuration as in Figure 1, except that a humidity sensor 9-2 is provided on the MPU 14-1. The humidity sensor 9-2 is located at any location within the magnetic disk drive to detect the humidity of the device's atmosphere. In Figure 2, the humidity sensor 9-2, like the temperature sensor 9-1, is installed in the empty space on the bottom wall 52a of the base 52, for example, between the flexible printed circuit board (FPC) unit 53 on which electronic components such as conversion connectors are mounted, and the magnetic disk 1. Additionally, a pressure sensor (not shown) and a temperature sensor similar to that in Figure 8 can be provided as needed.

[0041] In Example 6, for example, instead of starting to monitor the change in the amount of ascent at a time when it can operate in the background, the comparison and determination of the change in the amount of ascent is started at the time when it is determined that there is a change in humidity based on the humidity information from the humidity sensor 9-2. In the same manner as in Example 4, the change in the amount of ascent between two or more positions with different radial positions can be determined by the steps ST51 to ST57 in Figure 9. Humidity information from the humidity sensor 9-2 can be set to be acquired at regular intervals. The humidity difference between the acquired humidity information can be calculated by the calculation unit 63. Based on the humidity difference, the determination unit 64 can determine that there is a change in humidity.

[0042] Example 7 Example 7 shows an example where further comparison and evaluation are performed when the atmospheric pressure changes. Figure 11 shows a block diagram illustrating yet another example of the configuration of a magnetic recording and reproducing apparatus according to the second embodiment. As shown in Figure 11, the magnetic recording and playback device 203 has the same configuration as in Figure 1, except that the MPU 14-1 is equipped with a pressure sensor 9-3. The pressure sensor 9-3 is located at any location within the magnetic disk drive to detect the atmospheric pressure of the device. In Figure 2, the pressure sensor 9-3, like the temperature sensor 9-1, is installed in the empty space on the bottom wall 52a of the base 52, for example, between the flexible printed circuit board (FPC) unit 53 on which electronic components such as conversion connectors are mounted, and the magnetic disk 1. Additionally, a pressure sensor (not shown) and a temperature sensor similar to those in Figure 8 may be provided as needed.

[0043] In Example 6, for example, instead of starting to monitor the change in ascent amount at a timing that allows for background operation, the comparison and determination of the change in ascent amount is started at the timing when it is determined that there is a change in atmospheric pressure based on atmospheric pressure information from the atmospheric pressure sensor 9-3. In the same manner as in Example 4, the change in ascent amount between two or more positions with different radial positions can be determined by the steps ST51 to ST57 in Figure 9. The barometric pressure information from the barometric pressure sensor 9-3 can be set to be acquired at regular intervals. The calculation unit 63 can determine the barometric pressure difference between the acquired barometric pressure data. Based on the barometric pressure difference, the determination unit 64 can determine that there is a change in barometric pressure.

[0044] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of Symbols]

[0045] 1…Magnetic disk, 1a…Recording surface, 10, 10W, 10R…Heat-assisted magnetic recording head, 9-1…Temperature sensor, 9-2…Humidity sensor, 9-3…Barometric pressure sensor, 18…Host, 19…Head position control unit, 61…Write operation control unit, 62…Error rate measurement unit, 63…Calculation unit, 64…Determination unit, 65…Floating amount adjustment unit, 200, 201, 202…Magnetic recording and playback device

Claims

1. A method for adjusting a magnetic recording and playback device equipped with a heat-assisted magnetic recording head and a magnetic disk, At a first position on the recording surface of the magnetic disk, the heat-assisted magnetic recording head performs a first write operation. The heat-assisted magnetic recording head is sought to a second position on the recording surface that is radially different from the first position, and the first error rate is measured. After performing the second light operation at the second position, The second error rate is measured at the second position. The first difference between the first error rate and the second error rate is calculated, The heat-assisted magnetic recording head is sought to the first position to measure the third error rate. After the third light operation is performed in the first position, The fourth error rate is measured at the first position, The second difference between the third error rate and the fourth error rate is calculated, A method for adjusting a magnetic recording and playback device, comprising comparing the first difference and the second difference to determine the change in the amount of levitation between the first position and the second position.

2. Before determining the change in the amount of buoyancy, The heat-assisted magnetic recording head is sought to a third position, which is radially different from the first and second positions, and the fifth error rate is measured. After performing the fourth light operation at the third position, the sixth error rate is measured. This further includes determining the third difference between the fifth error rate and the sixth error rate, The adjustment method for a magnetic recording and playback apparatus according to claim 1, wherein determining the change in the amount of levitation involves comparing the first difference, the second difference, and the third difference to determine the change in the amount of levitation at the first position, the second position, and the third position.

3. When the temperature inside the magnetic recording and playback device changes, The heat-assisted magnetic recording head is sought to a fourth position, which is radially different from the first and second positions, and the sixth error rate is measured. After performing the fifth light operation at the fourth position, the seventh error rate is measured, and The fourth difference between the sixth error rate and the seventh error rate is calculated. The adjustment method for a magnetic recording and reproducing apparatus according to claim 1, further comprising comparing the first difference and / or the second difference with the fourth difference to determine the change in the amount of levitation at the fourth position.

4. When the humidity of the magnetic recording and playback device changes, The heat-assisted magnetic recording head is sought to a fourth position, which is radially different from the first and second positions, and the sixth error rate is measured. After performing the fifth light operation at the fourth position, the seventh error rate is measured, and The fourth difference between the sixth error rate and the seventh error rate is calculated. The adjustment method for a magnetic recording and reproducing apparatus according to claim 1, further comprising comparing the first difference and / or the second difference with the fourth difference to determine the change in the amount of levitation at the fourth position.

5. When the air pressure inside the magnetic recording and playback device changes, The heat-assisted magnetic recording head is sought to a fourth position, which is radially different from the first and second positions, and the sixth error rate is measured. After performing the fifth light operation at the fourth position, the seventh error rate is measured, and The fourth difference between the sixth error rate and the seventh error rate is calculated. The adjustment method for a magnetic recording and reproducing apparatus according to claim 1, further comprising comparing the first difference and / or the second difference with the fourth difference to determine the change in the amount of levitation at the fourth position.

6. When monitoring the magnetic recording and playback device in the background, The heat-assisted magnetic recording head is sought to a fourth position, which is radially different from the first and second positions, and the sixth error rate is measured. After performing the fifth light operation at the fourth position, the seventh error rate is measured, and The fourth difference between the sixth error rate and the seventh error rate is calculated. The adjustment method for a magnetic recording and reproducing apparatus according to claim 1, further comprising comparing the first difference and / or the second difference with the fourth difference to determine the change in the amount of levitation at the fourth position.

7. A method for adjusting a magnetic recording and playback apparatus according to any one of claims 1 to 6, further comprising adjusting the amount of levitation of the heat-assisted magnetic recording head if, as a result of the above determination, it is determined that there is a change in the amount of levitation.

8. The adjustment method for a magnetic recording and playback device according to claim 6, further comprising notifying an externally connected host if, as a result of the above determination, it is determined that there is a change in the amount of levitation.

9. The notification to the host is a method for adjusting a magnetic recording and playback device according to claim 8, which utilizes the SMART function.

10. A magnetic disk comprising a magnetic recording layer and a lubricant provided on the recording surface of the magnetic recording layer, A heat-assisted magnetic recording head for performing magnetic recording on the magnetic disk, A head position control unit that positions the heat-assisted magnetic recording head at a first position on the recording surface, or at a second position that is radially different from the first position. A light operation control unit that controls the first light operation at the first position, the second light operation at the second position, and the third light operation at the first position, respectively. An error rate measuring unit that measures the first error rate before the second light operation, the second error rate after the second light operation, the third error rate before the third light operation, and the fourth error rate after the third light operation. A calculation unit that calculates the first difference between the first error rate and the second error rate, and the second difference between the third error rate and the fourth error rate, and A magnetic recording and playback apparatus including a determination unit that compares the first difference and the second difference and determines a change in the amount of levitation.

11. The head position control unit further positions the heat-assisted magnetic recording head at a third position that is radially different from the first and second positions. The light operation control unit further controls the operation of the fourth light at the third position, The error rate measuring unit further measures the fifth error rate before the fourth light operation and the sixth error rate after the fourth light operation. The calculation unit further determines the third difference between the fifth error rate and the sixth error rate, and The magnetic recording and regeneration apparatus according to claim 10, further comprising the determination unit comparing the first difference, the second difference, and the third difference to determine the change in the amount of levitation.

12. Further including a temperature sensor, The head position control unit seeks the heat-assisted magnetic recording head to a fourth position that is radially different from the first and second positions. The light operation control unit performs the fifth light operation at the fourth position. The error rate measuring unit measures the sixth error rate before the fifth light operation and the seventh error rate after the fifth light operation, and The calculation unit determines the temperature difference within the magnetic recording and playback device based on the temperature information from the temperature sensor, and determines the fourth difference between the sixth error rate and the seventh error rate. The magnetic recording and reproducing apparatus according to claim 10, wherein the determination unit determines the temperature change based on the temperature difference information, compares the first difference and / or the second difference with the fourth difference, and determines the change in the amount of levitation at the fourth position.

13. It further includes a humidity sensor, The head position control unit seeks the heat-assisted magnetic recording head to a fourth position that is radially different from the first and second positions. The light operation control unit performs the fifth light operation at the fourth position. The error rate measuring unit measures the sixth error rate before the fifth light operation and the seventh error rate after the fifth light operation, and The calculation unit determines the humidity difference within the magnetic recording and playback device based on the humidity information from the humidity sensor, and determines the fourth difference between the sixth error rate and the seventh error rate. The magnetic recording and regeneration apparatus according to claim 10, wherein the determination unit determines a change in humidity based on the humidity difference information, compares the first difference and / or the second difference with the fourth difference, and determines a change in the amount of levitation at the fourth position.

14. It further includes a barometric pressure sensor, The head position control unit seeks the heat-assisted magnetic recording head to a fourth position that is radially different from the first and second positions. The light operation control unit performs the fifth light operation at the fourth position. The error rate measuring unit measures the sixth error rate before the fifth light operation and the seventh error rate after the fifth light operation, and The calculation unit determines the pressure difference within the magnetic recording and playback device based on the pressure information from the pressure sensor, and determines the fourth difference between the sixth error rate and the seventh error rate. The magnetic recording and reproducing apparatus according to claim 10, wherein the determination unit determines a change in atmospheric pressure based on the information of the atmospheric pressure difference, compares the first difference and / or the second difference with the fourth difference, and determines the change in the amount of levitation at the fourth position.

15. The aforementioned heat-assisted magnetic recording head can operate in the background. The head position control unit seeks the heat-assisted magnetic recording head to a fourth position that is radially different from the first and second positions. The light operation control unit performs the fifth light operation at the fourth position. The error rate measuring unit measures the sixth error rate before the fifth light operation and the seventh error rate after the fifth light operation, and The calculation unit calculates the fourth difference between the sixth error rate and the seventh error rate, The magnetic recording and regeneration apparatus according to claim 10, wherein the determination unit compares the first difference and / or the second difference with the fourth difference to determine the change in the amount of levitation at the fourth position.

16. The system further includes a floating amount adjustment unit for adjusting the floating amount of the heat-assisted magnetic recording head, If, as a result of the above determination, it is determined that there is a change in the amount of levitation, the levitation amount adjustment unit adjusts the amount of levitation of the heat-assisted magnetic recording head, as described in any one of claims 10 to 15.

17. This further includes external connections to the host, The magnetic recording and playback device according to claim 15, which notifies the host if, as a result of the above determination, it is determined that there is a change in the amount of levitation.

18. The notification to the host is made using the smart function of the magnetic recording and playback device according to claim 17.

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