Magnetic recording and reproducing apparatus and method for adjusting same

Abstract

The invention provides a magnetic recording and reproducing apparatus including determining a change in a floating amount of a heat-assisted magnetic recording head, and a method for adjusting the same. A method of adjusting a magnetic recording / reproducing apparatus according to an embodiment is a method of adjusting a magnetic recording / reproducing apparatus in which a heat-assisted magnetic recording head and a magnetic disk are mounted, the method performing a first write operation at a first position on a recording surface, measuring a first error rate at a second position different from the first position in a radial direction, and after performing a second write operation, measuring a second error rate at a second position different from the first position. A first error rate is measured at a first position, a second error rate is measured at a second position, a first difference between the first error rate and the second error rate is obtained, a third error rate is measured at a first position, after a third write operation is performed, a fourth error rate is measured, a second difference between the third error rate and the fourth error rate is obtained, the first difference and the second difference are compared, and a change in the floating amount is determined.

Description

[0001] This application claims the priority of Japanese Patent Application No. 2023-158269 (filing date: September 22, 2023) as a basic application, and the entire contents of the basic application are incorporated herein by reference. Technical Field

[0002] Embodiments of the present invention relate to a magnetic recording and reproducing device and an adjustment method thereof. Background Art

[0003] In a heat-assisted magnetic recording head, laser light is used to raise the temperature of a magnetic disk for recording. At this time, it is known that due to the temperature rise, components believed to be from the magnetic film of the magnetic disk adhere to the tip of the near field optical element (NFT) through the lubricant and form a solid.

[0004] The generation of the lubricant solidified product cannot be prevented due to the principle of recording. On the other hand, it is known that when the lubricant solidified product is adhered and fixed, the transmittance of the laser light increases and the layer functions as a layer that improves the transmission efficiency of the laser light.

[0005] If the floating amount is reduced, the lubricant solid will be worn away by abrasion, and if the floating amount is increased, it will be rebuilt by filling the lubricant between the head and the medium. Therefore, when the floating amount changes in the disk surface, for example, when the magnetic head moves from a track with a lower floating amount to a track with a higher floating amount, the problem of decreased write performance will occur during the period until the lubricant solid is generated.

[0006] In addition, the floating amount adjustment accuracy of the write head and NFT is lower than that of the read head. Therefore, it is desirable to adjust the floating amount of the write head so that there is no difference in error rate between immediately after seek and after full writing.

[0007] Furthermore, when the temperature changes and / or regarding floating monitoring at the user side, it is desired to similarly adjust the floating amount. Summary of the invention

[0008] Embodiments of the present invention provide a magnetic recording and reproducing device including a method for determining a change in the flying height of a thermally assisted magnetic recording head and an adjustment method thereof.

[0009] The adjustment method of the magnetic recording and reproducing device of the present embodiment performs a first write operation at a first position on the recording surface of the magnetic disk using a thermally assisted magnetic recording head, causes the thermally assisted magnetic recording head to seek to a second position on the recording surface whose radial position is different from the first position, measures a first error rate, and after performing a second write operation at the second position, measures a second error rate, and obtains a first difference (difference) between the first error rate and the second error rate, causes the thermally assisted magnetic recording head to seek to the first position, measures a third error rate, and after performing a third write operation at the first position, measures a fourth error rate, and obtains a second difference between the third error rate and the fourth error rate, and compares the first difference with the second difference to determine a change in the floating amount. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 This is a block diagram showing the structure of an example of a magnetic recording and reproducing device according to the second embodiment.

[0011] Figure 2 This is a part of an exploded perspective view of the magnetic recording and reproducing device according to the second embodiment.

[0012] Figure 3 It is a side view showing the magnetic head and the suspension.

[0013] Figure 4 This is a cross-sectional view of a portion of the magnetic recording and reproducing device according to the second embodiment.

[0014] Figure 5 This is a flowchart showing an example of the adjustment method of the magnetic recording and reproducing device according to the first embodiment.

[0015] Figure 6 Yes means Figure 5 A block diagram of another example of an MPU.

[0016] Figure 7 This is a flowchart showing another example of the adjustment method of the magnetic recording and reproducing device according to the first embodiment.

[0017] Figure 8 This is a flowchart showing another example of the adjustment method of the magnetic recording and reproducing device according to the first embodiment.

[0018] Fig. 9 This is a flowchart showing another example of the adjustment method of the magnetic recording and reproducing device according to the first embodiment.

[0019] Fig.10 This is a block diagram showing the structure of another example of the magnetic recording and reproducing device according to the second embodiment.

[0020] Fig.11This is a block diagram showing the structure of another example of the magnetic recording and reproducing device according to the second embodiment.

[0021] Fig.12 This is a block diagram showing the structure of another example of the magnetic recording and reproducing device according to the second embodiment.

[0022] Description of symbols

[0023] 1…Magnetic disk, 1a…Recording surface, 10, 10W, 10R…Heat-assisted magnetic recording head, 9-1…Temperature sensor, 9-2…Humidity sensor, 9-3…Air pressure sensor, 18…Host, 19…Head position control unit, 61…Write operation control unit, 62…Error rate measurement unit, 63…Calculation unit, 64…Judgment unit, 65…Floating amount adjustment unit, 200, 201, 202…Magnetic recording and reproducing device DETAILED DESCRIPTION

[0024] The first embodiment of the adjustment method of the magnetic recording and reproducing device is an adjustment method of the magnetic recording and reproducing device equipped with a thermally assisted magnetic recording head and a magnetic disk, comprising: performing a first write operation at a first position on the recording surface of the magnetic disk using the thermally assisted magnetic recording head, causing the thermally assisted magnetic recording head to seek to a second position on the recording surface whose radial position is different from the first position, measuring a first error rate, after performing a second write operation at the second position, measuring a second error rate, and obtaining a first difference between the first error rate and the second error rate, causing the thermally assisted magnetic recording head to seek to the first position, measuring a third error rate, after performing a third write operation at the first position, measuring a fourth error rate, and obtaining a second difference between the third error rate and the fourth error rate, comparing the first difference with the second difference, and determining a change in floating amount.

[0025] The magnetic recording and reproducing device of the second embodiment is an example of a device for implementing the adjustment method of the magnetic recording and reproducing device of the first embodiment, comprising: a magnetic disk including a magnetic recording layer and a lubricant arranged on the recording surface of the magnetic recording layer; a thermally assisted magnetic recording head for performing magnetic recording on the magnetic disk; a head position control unit for configuring the thermally assisted magnetic recording head at a first position on the recording surface, or a second position whose radial position is different from the first position; a write action control unit for controlling a first write action at the first position, a second write action at the second position, and a third write action at the first position, respectively; an error rate measuring unit for measuring a first error rate before the second write action, a second error rate after the second write action, a third error rate before the third write action, and a fourth error rate after the third write action; a calculation unit for respectively calculating 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; and a determination unit for comparing the first difference with the second difference to determine a change in floating amount.

[0026] According to the first embodiment and the second embodiment, by obtaining the difference of the error rate before and after the write operation at two or more positions with different radial positions and comparing them, the floating amount change of the thermally assisted magnetic recording head can be determined. In addition, based on the obtained difference and the floating amount change, the floating amount of the thermally assisted magnetic recording head can be adjusted.

[0027] Example

[0028] Example 1

[0029] Hereinafter, embodiments will be described with reference to the drawings.

[0030] In addition, the disclosure is only an example, and appropriate changes that can be easily thought of by those skilled in the art while maintaining the main purpose of the invention are of course included in the scope of the present invention. In addition, in order to make the description clearer, the drawings sometimes schematically show the width, thickness, shape, etc. of each part compared with the actual form, but this is only an example and does not limit the interpretation of the present invention. In addition, in this specification and each figure, the same reference numerals are marked for the same elements as those previously described in the existing figures, and the detailed description is sometimes appropriately omitted.

[0031] First, refer to Figure 1 , the structure of an example of a disk drive related to the second embodiment is described. In addition, Figure 1 The structure of the disk drive as a magnetic recording and reproducing device shown above is also applicable to each embodiment described later.

[0032] like Figure 1 As shown, the disk drive 200 is a magnetic disk device of a perpendicular magnetic recording system in which a magnetic disk 1 as a perpendicular magnetic recording medium and a magnetic head 10 having a magnetic flux control layer described later are mounted.

[0033] Figure 2 This is a part of an exploded perspective view of the magnetic recording and reproducing device according to the second embodiment.

[0034] Figure 2 In the magnetic recording and reproducing device of the second embodiment, a plurality of magnetic disks 1 and a plurality of magnetic heads 10 are accommodated in a housing 51, and a cover portion is omitted.

[0035] The magnetic disk 1 is fixed to a spindle motor (SPM) 2 and is mounted so as to perform rotational movement. The magnetic head 10 is mounted on an actuator 3 and is configured to be movable in a radial direction on the magnetic disk 1. The actuator 3 is rotationally driven by a voice coil motor (VCM) 4. Figure 1For example, it is possible to show a situation where the magnetic head 10 seeks to the first position on the recording surface 1a, and it is possible to show a situation where the magnetic head 10' mounted on the actuator 3' seeks to the second position which is different from the first position in the radial direction. The magnetic head 10 includes: a write head 10W, a read head 10R, and a thermal 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 thermal assist unit 100 assists in writing data when the write head 10W writes data to the magnetic disk 1. The magnetic head 10 can include a single head or a plurality of heads.

[0036] Furthermore, the disk drive includes a head amplifier integrated circuit (hereinafter referred to as a 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 a memory 17. The R / W channel 12, the HDC 13, and the MPU 14 are incorporated into a controller 15 formed of a single-chip integrated circuit.

[0037] As described later, the head amplifier IC11 includes a circuit group for driving a laser diode for performing heat assist. Furthermore, the head amplifier IC11 includes a driver for supplying a recording signal (write current) corresponding to write data supplied from the R / W channel 12 to the recording head 10W. In addition, the head amplifier IC11 includes a read amplifier for amplifying a read signal output from the reproduction head 10R and transmitting the amplified read signal to the R / W channel 12.

[0038] The R / W channel 12 is a signal processing circuit for reading / writing data. The HDC 13 constitutes an interface between the disk drive and the host computer 18, and performs transfer control of read / write data.

[0039] MPU14 is the main control unit of the disk drive, and performs the control of the read / write action and the servo control required for the positioning of the magnetic head 10. Furthermore, MPU14 includes: a head position control unit 19, which configures the thermally assisted magnetic recording head 10 at the first position on the recording surface, or at the second position whose radial position is different from the first position; a write action control unit 61, which controls the first write action at the first position, the second write action at the second position, and the third write action at the first position; an error rate measurement unit 62, which measures the first error rate before the second write action, the second error rate after the second write action, the third error rate before the third write action, and the fourth error rate after the third write action; a calculation unit 63, which respectively 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 determination unit 64, which compares the first difference with the second difference to determine the change in the floating amount.

[0040] The memory 17 includes a buffer memory constituted by a DRAM, a flash memory, and the like.

[0041] The temperature sensor 9 - 1 can be installed in a vacant space on the bottom wall 52 a of the base 52 , for example, between a substrate unit (FPC unit) 53 on which electronic components such as a conversion connector are mounted and the magnetic disk 1 , and can be arbitrarily installed as required.

[0042] Figure 3 It is a side view showing the magnetic head 10 and the suspension.

[0043] like Figure 3 As shown in FIG. 1 , each magnetic head 10 is constructed as a floating head, and has a slider 42 of a substantially rectangular parallelepiped shape and a head 44 for recording and reproducing provided at the outflow end (trailing end) of the slider 42. The magnetic head 10 is fixed to a universal spring 41 provided at the front end of the suspension 34. Using the elasticity of the suspension 34, each magnetic head 10 is applied with a head load L toward the surface of the magnetic disk 1. Figure 2 As shown, each magnetic head 10 is connected to the head amplifier IC 11 and the HDC 13 via a wiring member (flexure) 35 fixed to the suspension 34 and the arm.

[0044] Next, the configurations of the magnetic disk 1 and the magnetic head 10 will be described in detail.

[0045] Figure 4 It is a cross-sectional view of a write head 10W and a magnetic disk 1 which are parts of a magnetic disk device.

[0046] The magnetic disk 1 has a substrate 20, and a heat sink layer 21, a crystal orientation layer 22, a perpendicular recording layer 23, and a protective film 24 with a lubricant applied on the surface, which are sequentially stacked on the substrate 20. The perpendicular recording layer 23 has a large anisotropy in a direction perpendicular to the disk surface. The crystal orientation layer 22 is arranged below the perpendicular recording layer 23 to improve the orientation of the perpendicular recording layer 23. The heat sink layer 21 is arranged below the crystal orientation layer 22 to suppress the expansion of the heating area. The protective film 24 is arranged on the upper part of the perpendicular recording layer 23 to protect the perpendicular recording layer 23.

[0047] The magnetic head 10 is a separated type magnetic head in which a recording head 10W and a reproducing head 10R are separated. The recording head 10W includes: a main magnetic pole 40 formed of a high magnetic permeability material that generates a vertical magnetic field relative to the disk surface, a trailing magnetic yoke 50 magnetically coupled to the main magnetic pole 40 to allow magnetic flux to flow through the main magnetic pole 40, a return shielding magnetic pole 60 arranged on the leading side of the main magnetic pole 40 to effectively close the magnetic circuit directly below the main magnetic pole, a coil 70 arranged to be wound around the magnetic circuit including the trailing magnetic yoke and the return shielding magnetic pole in order to allow magnetic flux to flow through the main magnetic pole 40, a heater 80 for controlling the floating height of the recording head, a near-field optical element 30 for generating near-field light that heats the vertical recording layer 23 of the magnetic disk 1 on the leading side of the main magnetic pole 40, and a waveguide 31 for transmitting light for generating near-field light. The light source is incorporated in a manner that a laser diode 32 is mounted on a slider of the actuator assembly 3. For example, Au, Pd, Pt, Rh, Ir, or an alloy formed by a combination of several of them can be used as the near field optical element 30. For example, an oxide formed of SiO2, Al2O3, etc. can be used as the insulating layer provided between the main magnetic pole and the near field optical element.

[0048] As recording methods that can be used for heat-assisted magnetic recording of the magnetic disk device 200, there are: a conventional recording method in which writing is performed on tracks at intervals in the radial direction so that adjacent tracks do not overlap, namely the so-called CMR (Conventional Magnetic Recording); a shingled recording method in which tracks overlap in sequence in the radial direction and are recorded overlapping with a portion of an adjacent track, namely the so-called SMR (Shingled Magnetic Recording); an interlaced recording method in which bottom tracks and top tracks overlap adjacent tracks differently, and after recording on the bottom track, recording is performed on an interlaced top track in an overlapping manner with the bottom track; or a combination thereof.

[0049] Figure 5 Shows that the Figure 1 FIG. 1 is a flowchart of an example of a method for adjusting the magnetic recording and reproducing device according to the first embodiment shown in FIG.

[0050] Example 1 shows an example of comparing the floating amounts between two positions having different radial positions as an example of the adjustment method using the magnetic recording and reproducing device of the first embodiment.

[0051] As shown in the figure, the adjustment method of the magnetic recording and reproducing device is started. First, at the first position of the recording surface of the magnetic disk, the thermally assisted magnetic recording head 10 is controlled by the writing operation control unit 61 to perform the first writing operation (ST1) to form a lubricant solidified product. Next, the thermally assisted magnetic recording head 10 is controlled by the head position control unit 19 to seek to the second position of the recording surface which is different from the first position in the radial direction, and the first error rate is measured by the error rate measuring unit 62 (ST2). Next, the thermally assisted magnetic recording head is controlled by the writing operation control unit 61 to perform the second writing operation (ST3) at the second position to form a lubricant solidified product. Then, the second error rate is measured by the error rate measuring unit 62 at the second position (ST4), and the first difference between the first error rate and the second error rate is obtained by the calculation unit 63 (ST5). Next, the thermally assisted magnetic recording head 10 is controlled by the head position control unit 19 to seek to the first position, and the third error rate is measured by the error rate measuring unit 62 (ST6). Then, the thermally assisted magnetic recording head 10 is controlled by the writing operation control unit 61 to perform the third writing operation at the first position (ST7) to form a lubricant solidified material. Then, the fourth error rate is measured at the first position by the error rate measuring unit 62 (ST8), and the second difference between the third error rate and the fourth error rate is obtained by the calculation unit 63 (ST9). Next, the first difference and the second difference are compared by the determination unit 64 to determine the change in the floating amount (ST10), and the process ends. Thus, the floating comparison between two different positions is performed.

[0052] The lower one of the absolute value of the first difference and the absolute value of the second difference can be determined as the upper lower one.

[0053] The radial position here can be determined by the distance from the center of the recording surface 1a of the magnetic disk 1. For example, the second position having a radial position different from the first position means that when the first position is on a concentric circle having a first distance from the center of the recording surface 1a of the magnetic disk 1, the second position is on a concentric circle having a second distance different from the first distance from the center of the recording surface 1a.

[0054] In addition, the first write operation, the second write operation, and the third write operation can be continuously written (write) for a predetermined time, for example, a time sufficient for forming a lubricant solidified material. The predetermined time of the write operation can be determined by the time until the difference in error rate disappears. For example, it can be set to 1 to 3 seconds. The predetermined time can be set to the same time in, for example, the first write operation, the second write operation, and the third write operation.

[0055] In the measurement of error rates such as the first error rate, the second error rate, the third error rate, and the fourth error rate, writing and reproduction of data for measuring the error rates can be performed.

[0056] According to an embodiment, the error rate before and after the writing operation is measured at two or more positions in different radial directions of the recording surface 1a, and the difference is calculated and compared, thereby being able to determine the change in floating amount based on the formation of lubricant solidification. In the event of a change in floating amount, it is possible to determine which floating amount to use as a reference.

[0057] For example, it is possible to determine the change in the floating amount at three positions that are different in the radial direction. In this case, in the adjustment method of the magnetic recording and reproducing device of the first embodiment, after the second difference is obtained, the head position control unit 19 controls the thermally assisted magnetic recording head 10 to seek to a third position that is different from the first position and the second position in the radial direction, and the error rate measuring unit 62 measures the fifth error rate. Then, after the fourth write action is performed at the third position by controlling the thermally assisted magnetic recording head 10 by the write action control unit 61, the sixth error rate is measured by the error rate measuring unit 62. Then, it may also include: obtaining the third difference between the fifth error rate and the sixth error rate by the calculation unit 63, comparing the first difference, the second difference and the third difference by the determination unit 64, and determining the change in the floating amount.

[0058] In addition, the floating amount can be adjusted so that there is no difference in error rate at two or more positions that are different in the radial direction. Thus, the heights of the lubricant solidified material at two or more positions that are different in the radial direction can be aligned (consistent).

[0059] In the adjustment method of the magnetic recording and reproducing device of the first embodiment, it is also possible to perform the writing operation again at an arbitrary timing, measure the error rates before and after, and obtain the difference in the error rates for comparison and determination.

[0060] Such timing can be freely set, for example, before shipment after manufacturing, after shipment, at a certain time, when the temperature changes, or when the humidity changes.

[0061] In addition, as required, after leaving the factory, for example, at the user side, the error rate before and after the write action can also be measured, and the difference can be calculated for comparison, thereby monitoring the floating amount change. And then the floating amount can be adjusted arbitrarily according to the floating amount change. Such monitoring of the floating amount change can be performed in the background when the magnetic recording and reproducing device 200 does not perform the recording and reproducing action. As the position for performing the write action, the user area on the recording surface can be used, or a test cylinder (cylinder) for setting the test can be used.

[0062] In addition, when it is determined that the floating amount has changed, it is possible to notify the host 18. In this case, the host 18 can be notified using the SMART (Self-Monitoring Analysis and Reporting Technology) function.

[0063] The magnetic disk 1 included in the magnetic recording and reproducing device 200 of the embodiment can use a perpendicular magnetic recording medium. The perpendicular magnetic recording medium can include, for example, a granular magnetic recording layer. The granular magnetic recording layer includes magnetic particles having an L10 structure as a magnetic material. As magnetic particles having an L10 structure, FePt alloy particles, CoPt alloy particles, etc. can be listed. As grain boundaries, oxides containing C, BN, SiO2, etc. can be included as grain boundary materials. The lubricant solid is considered to be: a solidified material generated by the components derived from the magnetic recording layer, such as SiO2 contained in the grain boundary, attached to the front end of the NFT with the help of a lubricant. In addition, a protective layer can be provided on the magnetic recording layer. As a protective layer, for example, carbon (C), diamond-like carbon, SiO2, and ZrO2 can be used. As a lubricant suitable for the recording surface of the magnetic disk, for example, perfluoropolyether, fluorinated alcohol, and fluorinated carboxylic acid can be used.

[0064] Example 2

[0065] Example 2 As another example of the adjustment method of the magnetic recording and reproducing device of the first embodiment, an example of adjusting the floating amount based on the determination result of the floating amount change is shown.

[0066] Figure 6 An example of an MPU used in another example of the magnetic recording and reproducing device according to the second embodiment is shown.

[0067] The MPU 14-2 has the following features in addition to the floating amount adjustment unit 65: Figure 1 The magnetic recording and reproducing device used in Example 2 is another example of the magnetic recording and reproducing device of the second embodiment, except that the MPU 14-1 is replaced with Figure 6 In addition to the MPU14-2, it has Figure 1 Same composition.

[0068] Figure 7 A flowchart showing another example of the adjustment method of the magnetic recording and reproducing device according to the first embodiment is shown.

[0069] As shown in the figure, the adjustment of the magnetic recording and reproducing device is started. First, at the first position of the recording surface 1a of the magnetic disk 1, the thermally assisted magnetic recording head 10 is controlled by the writing operation control unit 61 to perform the first writing operation (ST11) to form a lubricant solidified product. Next, the thermally assisted magnetic recording head 10 is controlled by the head position control unit 19 to seek to the second position of the recording surface 1a which is different from the first position in the radial direction, and the first error rate is measured by the error rate measuring unit 62 (ST12). Next, the thermally assisted magnetic recording head is controlled by the writing operation control unit 61 to perform the second writing operation (ST13) at the second position to form a lubricant solidified product. Then, the second error rate is measured by the error rate measuring unit 62 at the second position (ST14), and the first difference between the first error rate and the second error rate is obtained by the calculation unit 63 (ST15). Next, the thermally assisted magnetic recording head 10 is controlled by the head position control unit 19 to seek to the first position, and the third error rate is measured by the error rate measuring unit 62 (ST16). Then, the thermally assisted magnetic recording head 10 is controlled by the writing operation control unit 61 to perform the third writing operation at the first position (ST17) to form the lubricant solidified material. Then, the error rate measuring 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). The steps from ST11 to ST19 are the same as the steps from ST1 to ST9 of the adjustment method of the first embodiment.

[0070] Next, the determination unit 64 compares the first difference and the second difference to determine whether the floating amount has changed (ST20). If the result of the determination is that there is a floating amount change, the floating amount adjustment unit 65 adjusts the floating amount (ST21), and then the steps from ST11 to ST20 are repeated. On the other hand, if there is no floating amount change, the process ends. Thus, the floating amounts of two different positions can be compared and adjusted.

[0071] In addition, when the floating amount changes, for example, the lower of the absolute value of the first difference and the absolute value of the second difference can be determined as the reference radial position. In adjusting the floating amount, the floating amount can be reduced until the difference in error rate of the radial position other than the reference radial position is equal to the difference in error rate of the reference radial position. In this way, the heights of the lubricant solidified material at the two positions can be aligned.

[0072] Example 3

[0073] Example 3 As another example of the adjustment method of the magnetic recording and reproducing device of the first embodiment, an example of determining the change in the floating amount at three different positions in the radial direction is shown.

[0074] Figure 8This is a flowchart showing still another example of the adjustment method of the magnetic recording and reproducing device according to the first embodiment.

[0075] Here, the same magnetic recording and reproducing device as in Example 2 can be used.

[0076] As shown in the figure, first, the adjustment of the magnetic recording and reproducing device is started, and through ST31 to ST39, the first difference and the second difference are obtained in the same manner as ST11 to ST19 of the second embodiment.

[0077] Next, the head position control unit 19 controls the thermally assisted magnetic recording head 10 to seek to a third position different from the first position and the second position in the radial direction, and the error rate measuring unit 62 measures the fifth error rate (ST40). The writing operation control unit 61 controls the thermally assisted magnetic recording head 10 to perform the fourth writing operation at the third position (ST41). After that, the error rate measuring unit 62 measures the sixth error rate (ST42), and 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 floating amount (ST44). The error rate measuring unit 62 measures the fifth error rate before the fourth writing operation and the sixth error rate after the fourth writing operation.

[0078] In addition, if there is a change in the floating amount, the floating amount is adjusted by the floating amount adjustment unit 65 (ST45), and then the steps from ST31 to ST43 are repeated. On the other hand, if there is no change in the floating amount, the process can be terminated. Thus, the floating amounts between the three different positions are compared and adjusted. Figure 8 In the present invention, after ST44, the floating amount is adjusted in ST45 as needed, but it is also possible to complete the adjustment method of the magnetic recording and reproducing device by only performing the determination in ST44.

[0079] When the floating amount changes, for example, the lowest of the absolute value of the first difference, the absolute value of the second difference, and the absolute value of the third difference can be determined as the reference radial position. In adjusting the floating amount, the floating amount can be reduced until the difference in error rate of the radial position other than the reference radial position is equal to the difference in error rate of the reference radial position. In this way, the heights of the lubricant solidified material at the three positions can be aligned.

[0080] Example 4

[0081] Example 4 As still another example of the adjustment method of the magnetic recording and reproducing device of the first embodiment, an example of monitoring the change of the floating amount in the background is shown.

[0082] Fig. 9This is a flowchart showing still another example of the adjustment method of the magnetic recording and reproducing device according to the first embodiment.

[0083] Here, the same magnetic recording and reproducing device as in Example 2 can be used.

[0084] First, similarly to the second embodiment, a magnetic recording and reproducing device is prepared in advance which obtains the first difference and the second difference, compares the floating amounts between two positions, and adjusts the floating amounts as necessary.

[0085] After writing in the user area, it is confirmed that the thermally assisted magnetic recording head can operate in the background, and monitoring of the floating amount change is started. The state of being able to operate in the background refers to a state where the head can operate in a place not visible to the user, such as an idle state.

[0086] First, the thermally assisted magnetic recording head 10 is controlled by the head position control unit 19, so that the thermally assisted magnetic recording head 10 seeks to a position in the radial direction different from the first position and the second position, such as a position of the test cylinder, as the fourth position, and the sixth error rate is measured (ST51). Next, the thermally assisted magnetic recording head 10 is controlled by the write action control unit 61, and the fifth write action is performed at the fourth position (ST52) to form a lubricant solid. Then, the seventh error rate is measured at the fourth position by the error rate measurement unit 62 (ST53). That is, in the error rate measurement unit 62, the sixth error rate before the fifth write action and the seventh error rate after the fifth write action are measured. Next, the fourth difference between the seventh error rate and the sixth error rate is calculated by the calculation unit 63 (ST54).

[0087] Next, the determination unit 64 compares the fourth difference with the first difference and / or the second difference obtained in advance, and determines whether or not there is a change in the floating amount (ST55).

[0088] If there is a change in the floating amount, determine whether the fourth difference is a negative value (ST56). If the fourth difference is a negative value, the monitoring is abnormally terminated. If the fourth difference is not a negative value, adjust the floating amount (ST57). Then, repeat ST51 to 55.

[0089] If there is no change in the floating amount, the monitoring of the floating amount change is terminated. Fig. 9 In the embodiment, after ST55, the determination in ST56 is performed, and the floating amount is adjusted in ST57 as needed, but it is also possible to perform only the determination in ST55 and end the monitoring of the floating amount change.

[0090] For example, when it is determined that the floating amount has changed, when monitoring is abnormally terminated, and when monitoring is terminated, the host computer 18 can be notified arbitrarily. In this case, the SMART function can be used.

[0091] As a result, for example, the change in the floating amount of the magnetic recording and reproducing device can be automatically monitored in the background without being seen by the user at any time before or after shipment.

[0092] In addition, Fig. 9 In the description, an example in which the radial position is different from the first position and the second position is cited as the fourth position, but the first position or the second position may be used as the fourth position.

[0093] Example 5

[0094] Example 5 shows an example in which a comparison and determination is further performed at the timing when the temperature changes.

[0095] Fig.10 A block diagram showing the structure of still another example of the magnetic recording and reproducing device according to the second embodiment is shown.

[0096] As shown in the figure, the magnetic recording and reproducing device 201 is the magnetic recording and reproducing device used in the fifth embodiment, and has a temperature sensor 9-1 connected to the MPU 14-1. Figure 1 Same composition.

[0097] Temperature sensor 9-1 Figure 2 As shown, it is installed at an arbitrary location in the magnetic disk device in order to detect the temperature of the device atmosphere.

[0098] In the fifth embodiment, for example, instead of starting to monitor the floating amount change at the time when the background can perform the action, the comparison and determination of the floating amount change can be started at the time when the temperature information from the temperature sensor 9-1 determines that there is a temperature change. In addition, as in the fourth embodiment, Fig. 9 The steps from ST51 to ST57 can determine the change in the floating amount between two or more positions having different radial positions.

[0099] The temperature information from the temperature sensor 9-1 can be set to be acquired at a fixed time. The temperature difference between the acquired temperature information can be obtained by the calculation unit 63. The determination unit 64 can determine the presence of temperature change based on the temperature difference.

[0100] Example 6

[0101] Example 6 shows an example in which a further comparison and determination is performed at the timing when the humidity changes.

[0102] Fig.11 A block diagram showing the structure of still another example of the magnetic recording and reproducing device according to the second embodiment is shown.

[0103] like Fig.11As shown, the magnetic recording and reproducing device 202 has a humidity sensor 9-2 in addition to the MPU 14-1. Figure 1 Same composition.

[0104] The humidity sensor 9-2 is installed at any place in the magnetic disk device in order to detect the humidity of the device atmosphere. Figure 2 In the embodiment, the humidity sensor 9-2 is provided in the same manner as the temperature sensor 9-1, in the free space on the bottom wall 52a of the base 52, for example, between the substrate unit (FPC unit) 53 on which electronic components such as a conversion connector are mounted and the magnetic disk 1. In addition, an air pressure sensor not shown in the figure and a Figure 8 Same temperature sensor.

[0105] In the sixth embodiment, for example, instead of starting to monitor the floating amount change at a time when the operation can be performed in the background, the comparison and determination of the floating amount change can be started when the humidity information from the humidity sensor 9-2 determines that there is a humidity change. In addition, as in the fourth embodiment, Fig. 9 In steps ST51 to ST57, the change in floating amount between two or more positions having different radial positions is determined.

[0106] The humidity information from the humidity sensor 9-2 can be set to be acquired at a fixed time. The humidity difference between the acquired humidity information can be obtained by the calculation unit 63. The determination unit 64 can determine the presence of humidity change based on the humidity difference.

[0107] Example 7

[0108] Example 7 shows an example in which a further comparison and determination is performed at the timing when the gas pressure changes.

[0109] Fig.11 A block diagram showing the structure of still another example of the magnetic recording and reproducing device according to the second embodiment is shown.

[0110] like Fig.11 As shown, the magnetic recording and reproducing device 203 has an air pressure sensor 9-3 provided for the MPU 14-1. Figure 1 Same composition.

[0111] The air pressure sensor 9-3 is installed at any place in the magnetic disk device in order to detect the air pressure of the device atmosphere. Figure 2 In the embodiment, the air pressure sensor 9-3 is provided in the same manner as the temperature sensor 9-1, in a free space on the bottom wall 52a of the base 52, for example, between a substrate unit (FPC unit) 53 on which electronic components such as a conversion connector are mounted and the magnetic disk 1. In addition, an air pressure sensor not shown in the figure may be further provided as required. Figure 8 Same temperature sensor.

[0112] In the sixth embodiment, for example, instead of starting to monitor the change in floating amount at a time when the operation can be performed in the background, the comparison and determination of the change in floating amount can be started when it is determined that there is a change in air pressure based on the air pressure information from the air pressure sensor 9-3. In addition, as in the fourth embodiment, Fig. 9 In steps ST51 to ST57, the change in floating amount between two or more positions having different radial positions is determined.

[0113] The atmospheric pressure information from the atmospheric pressure sensor 9 - 3 can be set to be acquired at a fixed time. The atmospheric pressure difference between the acquired atmospheric pressure information can be obtained by the calculation unit 63. The determination unit 64 can determine the presence of atmospheric pressure change based on the atmospheric pressure difference.

[0114] Several embodiments of the present invention have been described, but these embodiments are provided as examples and are not intended to limit the scope of the invention. These new embodiments can be implemented in various other ways, and various omissions, substitutions, and changes can be made without departing from the gist of the invention. These embodiments and their variations are included in the scope and gist of the invention, and are included in the invention described in the claims and the scope equivalent thereto.

Claims

1. A method for adjusting a magnetic recording and reproducing device, wherein the magnetic recording and reproducing device is equipped with a thermally assisted magnetic recording head and a magnetic disk, the method for adjusting the magnetic recording and reproducing device comprising: The thermally assisted magnetic recording head performs a first writing operation at a first position on the recording surface of the magnetic disk. causing the thermally assisted magnetic recording head to seek to a second position of the recording surface that is different from the first position in the radial direction, and measuring a first error rate; After the second writing operation is performed at the second position, measuring a second error rate at the second position, calculating a first difference between the first error rate and the second error rate, causing the thermally assisted magnetic recording head to seek to the first position and measuring a third error rate, After the third writing operation is performed at the first position, measuring a fourth error rate at said first position, calculating a second difference between the third error rate and the fourth error rate, The first difference and the second difference are compared to determine the change in floating amount between the first position and the second position.

2. The adjustment method of the magnetic recording and reproducing device according to claim 1, further comprising: Before determining the change in the floating amount, causing the thermally assisted magnetic recording head to seek to a third position different from the first position and the second position in the radial direction, and measuring a fifth error rate, After the fourth writing operation is performed at the third position, the sixth error rate is measured. Calculate the third difference between the fifth error rate and the sixth error rate, In determining the floating amount change, the first difference, the second difference, and the third difference are compared to determine the floating amount changes at the first position, the second position, and the third position.

3. The adjustment method of the magnetic recording and reproducing device according to claim 1, further comprising: When the temperature in the magnetic recording and reproducing device changes, causing the thermally assisted magnetic recording head to seek to a fourth position different from the first position and the second position in the radial direction, and measuring a sixth error rate, After performing a fifth write operation at the fourth position, measuring a seventh error rate, and Calculate the fourth difference between the sixth error rate and the seventh error rate, The first difference and / or the second difference is compared with the fourth difference to determine a change in the floating amount at the fourth position.

4. The adjustment method of the magnetic recording and reproducing device according to claim 1, further comprising: When the humidity of the magnetic recording and reproducing device changes, causing the thermally assisted magnetic recording head to seek to a fourth position different from the first position and the second position in the radial direction, and measuring a sixth error rate, After performing a fifth write operation at the fourth position, measuring a seventh error rate, and Calculate the fourth difference between the sixth error rate and the seventh error rate, The first difference and / or the second difference is compared with the fourth difference to determine a change in the floating amount at the fourth position.

5. The adjustment method of the magnetic recording and reproducing device according to claim 1, further comprising: When the air pressure in the magnetic recording and reproducing device changes, causing the thermally assisted magnetic recording head to seek to a fourth position different from the first position and the second position in the radial direction, and measuring a sixth error rate, After performing a fifth write operation at the fourth position, measuring a seventh error rate, and Calculate the fourth difference between the sixth error rate and the seventh error rate, The first difference and / or the second difference is compared with the fourth difference to determine a change in the floating amount at the fourth position.

6. The adjustment method of the magnetic recording and reproducing device according to claim 1, further comprising: When the magnetic recording and reproducing device is monitored in the background, causing the thermally assisted magnetic recording head to seek to a fourth position different from the first position and the second position in the radial direction, and measuring a sixth error rate, After performing a fifth write operation at the fourth position, measuring a seventh error rate, and Calculate the fourth difference between the sixth error rate and the seventh error rate, The first difference and / or the second difference is compared with the fourth difference to determine a change in the floating amount at the fourth position.

7. The adjustment method of the magnetic recording and reproducing device according to any one of claims 1 to 6, further comprising: If it is determined as a result of the determination that there is a change in the flying amount, the flying amount of the thermally-assisted magnetic recording head is adjusted.

8. The adjustment method of the magnetic recording and reproducing device according to claim 6, further comprising: If it is determined as a result of the determination that there is a change in the floating amount, a notification is made to an externally connected host.

9. The adjustment method of the magnetic recording and reproducing device according to claim 8, The notification to the host utilizes the SMART function, namely the Self-Monitoring Analysis and Reporting Technology function.

10. A magnetic recording and reproducing device, comprising: A magnetic disk including a magnetic recording layer and a lubricant disposed on a 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 configured to dispose the thermally assisted magnetic recording head at a first position on the recording surface or at a second position different from the first position in a radial direction; a write operation control unit for controlling 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 writing operation, measures a second error rate after the second writing operation, measures a third error rate before the third writing operation, and measures a fourth error rate after the third writing operation; a calculation unit that calculates 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; and The determination unit compares the first difference and the second difference to determine a change in floating amount.

11. The magnetic recording and reproducing device according to claim 10, The head position control unit further arranges the thermally assisted magnetic recording head at a third position different in radial direction from the first position and the second position. The write operation control unit further controls a fourth write operation at the third position. The error rate measuring unit further measures a fifth error rate before the fourth write operation and measures a sixth error rate after the fourth write operation. The calculation unit further calculates a third difference between the fifth error rate and the sixth error rate; and The determination unit further compares the first difference, the second difference, and the third difference to determine a change in floating amount.

12. The magnetic recording and reproducing device according to claim 10, Also includes temperature sensor, The head position control unit causes the thermally assisted magnetic recording head to seek to a fourth position which is different from the first position and the second position in the radial direction. The write operation control unit performs a fifth write operation at the fourth position, The error rate measuring unit measures a sixth error rate before the fifth write operation and a seventh error rate after the fifth write operation, and The calculation unit obtains a temperature difference in the magnetic recording and reproducing device based on the temperature information from the temperature sensor, and obtains a fourth difference between the sixth error rate and the seventh error rate. The determination unit determines a temperature change based on the information of the temperature difference, compares the first difference and / or the second difference with the fourth difference, and determines a change in the floating amount at the fourth position.

13. The magnetic recording and reproducing device according to claim 10, Also includes humidity sensor, The head position control unit causes the thermally assisted magnetic recording head to seek to a fourth position which is different from the first position and the second position in the radial direction. The write operation control unit performs a fifth write operation at the fourth position, The error rate measuring unit measures a sixth error rate before the fifth write operation and a seventh error rate after the fifth write operation, and The calculation unit calculates the humidity difference in the magnetic recording and reproducing device based on the humidity information from the humidity sensor, and calculates the fourth difference between the sixth error rate and the seventh error rate. The determination unit determines a change in humidity based on the information on the humidity difference, compares the first difference and / or the second difference with the fourth difference, and determines a change in the floating amount at the fourth position.

14. The magnetic recording and reproducing device according to claim 10, Also includes air pressure sensor, The head position control unit causes the thermally assisted magnetic recording head to seek to a fourth position which is different from the first position and the second position in the radial direction. The write operation control unit performs a fifth write operation at the fourth position, The error rate measuring unit measures a sixth error rate before the fifth write operation and a seventh error rate after the fifth write operation, and The calculation unit obtains the air pressure difference in the magnetic recording and reproducing device based on the air pressure information from the air pressure sensor, and obtains the fourth difference between the sixth error rate and the seventh error rate. The determination unit determines a change in air pressure based on the information on the air pressure difference, compares the first difference and / or the second difference with the fourth difference, and determines a change in floating amount at a fourth position.

15. The magnetic recording and reproducing device according to claim 10, The thermally assisted magnetic recording head can operate in the background. The head position control unit causes the thermally assisted magnetic recording head to seek to a fourth position which is different from the first position and the second position in the radial direction. The write operation control unit performs a fifth write operation at the fourth position, The error rate measuring unit measures a sixth error rate before the fifth write operation and a seventh error rate after the fifth write operation, and The calculation unit obtains a fourth difference between the sixth error rate and the seventh error rate, The determination unit compares the first difference and / or the second difference with the fourth difference to determine a change in the floating amount at the fourth position.

16. The magnetic recording and reproducing device according to any one of claims 10 to 15, The thermally assisted magnetic recording head further comprises a floating amount adjusting unit, wherein the floating amount adjusting unit adjusts the floating amount of the thermally assisted magnetic recording head. The floating amount adjusting section adjusts the floating amount of the thermally-assisted magnetic recording head when it is determined that there is a floating amount change as a result of the determination.

17. The magnetic recording and reproducing device according to claim 15, Also includes external connections to the host, If it is determined as a result of the determination that there is a change in the floating amount, the host is notified.

18. The magnetic recording and reproducing device according to claim 17, The notification to the host utilizes the SMART function, namely the Self-Monitoring Analysis and Reporting Technology function.

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