JP2010140578A - Flying height control method and magnetic storage device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flying height control method with which flying height of a magnetic head can be controlled with respect to the variation in atmospheric pressure, and to provide a magnetic storage device. <P>SOLUTION: The method includes: a temperature-obtaining step (S201) for obtaining ambient temperature being temperature of a measured magnetic storage device; a signal value obtaining step (S202) obtaining a signal value which is a value based on the signal of the prescribed frequency read from a magnetic recording medium by a magnetic head; and deciding steps (S203, S204, S205, S206, S208) for deciding the control height for controlling flying height of the magnetic head, on the basis of relation information which is previously generated information and which indicates the correspondence relation between ambient temperature and the signal value under the prescribed atmospheric pressure, with the obtained temperature being the ambient temperature obtained by the temperature obtaining step, and a first signal value being the signal value obtained by signal obtaining step. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a technique for controlling the flying height of a magnetic head.

Conventionally, in a magnetic storage device, a technique for controlling the flying height of a magnetic head with respect to a storage medium is known. As an example of such a technique, the flying height is maintained at a design value prepared in advance by controlling the current applied based on the measured temperature for a mechanism that adjusts the flying height by having a heat source in the magnetic head. The technique to do is known (refer patent document 1).
JP 2006-164388 A

  However, the fluctuation factors of the flying height of the magnetic head include atmospheric pressure fluctuation, slider thermal deformation due to temperature fluctuation, and gap deformation due to temperature fluctuation. The above-described conventional technique has a problem that it can cope only with the fluctuation of the flying height due to the fluctuation of temperature, and cannot cope with the fluctuation of the flying height with respect to the fluctuation of atmospheric pressure.

  The present invention has been made to solve the above-described problems, and provides a flying height control method and a magnetic storage device capable of controlling the flying height of a magnetic head with respect to fluctuations in atmospheric pressure. It is aimed.

  In order to solve the above-described problem, a flying height control method is a method for controlling a flying height of the magnetic head in a magnetic storage device that records a signal on a magnetic recording medium by a magnetic head, and the measured magnetic storage device A temperature acquisition step of acquiring an ambient temperature that is a temperature of the signal; a signal value acquisition step of acquiring a signal value that is a value based on a signal of a predetermined frequency read from the magnetic recording medium by the magnetic head; Relation information that is information indicating a correspondence relationship between the environmental temperature and the signal value under a predetermined atmospheric pressure, an acquisition temperature that is an environmental temperature acquired by the temperature acquisition step, and the signal A determination step for determining a control amount for controlling the flying height of the magnetic head based on the first signal value that is the signal value acquired in the value acquisition step. And a flop.

  The magnetic storage device is a device that records a signal on a magnetic recording medium by a magnetic head and controls the flying height of the magnetic head, and obtains an environmental temperature that is a measured temperature of the magnetic storage device. An acquisition unit; a signal value acquisition unit that acquires a signal value that is a value based on a signal having a predetermined frequency read from the magnetic recording medium by the magnetic head; and a predetermined atmospheric pressure that is generated in advance. The relationship information is information indicating the correspondence between the environmental temperature and the signal value below, the acquisition temperature is the environmental temperature acquired by the temperature acquisition unit, and the signal value acquired by the signal value acquisition unit And a determining unit that determines a control amount for controlling the flying height of the magnetic head based on a certain first signal value.

  According to the present invention, the flying height of the magnetic head can be controlled with respect to fluctuations in atmospheric pressure.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Embodiment 1 FIG.
First, the hardware configuration of the magnetic storage device according to the present embodiment will be described. FIG. 1 is a diagram showing a hardware configuration of the magnetic storage device according to the present embodiment.

  As shown in FIG. 1, the magnetic storage device 1 according to the present embodiment includes a head IC 10, an MPU (Micro Processing Unit) 11, a memory 12, a magnetic disk 13 as a storage medium, a temperature sensor 14, and a magnetic head 15. Is.

  The magnetic disk 13 is a magnetic storage medium in the present embodiment and records reference information (related information) described later in a predetermined storage area. The magnetic head 15 is a magnetic head that writes a recording signal on the magnetic disk 13 and reads the signal written on the magnetic disk 13 as a reproduction signal. The temperature sensor 14 is a sensor that measures the environmental temperature of the magnetic storage device 1. The temperature sensor 14 may be provided outside the magnetic storage device 1.

  Next, the configuration of the head IC will be described. FIG. 2 is a diagram illustrating a hardware configuration of the head IC. FIG. 3 is a diagram showing the configuration of the magnetic head. FIG. 4 is a diagram showing the configuration of the magnetic head when a piezoelectric element is used.

  As shown in FIG. 2, the head IC 10 includes a read amplifier 101, a write amplifier 102, a level measurement unit 103, a register 104, a D / A converter 105, and a heater amplifier 106. As shown in FIG. 3, the magnetic head 15 includes a slider attached to the arm and an insulating film at the tip of the slider. In addition, a recording / reproducing element 151 and a heater 152 are provided in the insulating film.

  The read amplifier 101 amplifies a reproduction signal when the magnetic head 15 reads from the magnetic disk 13. The write amplifier 102 amplifies the recording signal when the magnetic head 15 writes to the magnetic disk 13. The recording / reproducing element 151 is an element that converts a current as a recording signal into a magnetic field and records it on the magnetic disk 13 and converts a magnetic field generated from the magnetic disk 13 into an electric signal. The recording / reproducing element 151 may be composed of a recording element and a reproducing element. The level measuring unit 103 measures the level of the read signal amplified by the read amplifier 101. The heater 152 generates heat according to the input current. The insulating film expands due to the heat from the heater 152, and as a result, the flying height of the recording / reproducing element 151 relative to the magnetic disk 13 is adjusted. The adjustment of the flying height by the heater 152 is an example. For example, as shown in FIG. 4, a slider may be provided with a piezoelectric element, and the flying height may be adjusted by warping the slider with this piezoelectric element. The register is for inputting a set value of current to the heater 152. The D / A converter 105 converts the set value (digital value) input to the register into an analog value. The heater amplifier 106 amplifies the analog value converted by the D / A converter and supplies a current to the heater 152.

  Next, the configuration and operation of the level measurement unit will be described. FIG. 5 is a diagram illustrating a configuration of the level measurement unit. FIG. 6 is a diagram showing a waveform of a read signal and a substantially peak voltage.

  As shown in FIG. 5, the level measuring unit 103 includes a peak hold circuit 103a and an A / D converter 103b. The peak hold circuit 103a is a circuit including a diode D, a resistor R1, a resistor R2, and a capacitor C. The peak hold circuit 103a attenuates the sine wave as a readout signal shown in FIG. 6 with the voltage on the vertical axis and the time on the horizontal axis by the time constant of the resistor R1 and the capacitor C. As a result, a substantially peak voltage indicated by a broken line in FIG. 6 is extracted from the sine wave. The substantially peak voltage is converted into a digital value by the A / D converter, whereby level measurement data is obtained.

  The frequency of the read signal as the measurement signal is preferably as high as possible so that a temperature change based on a coercive force Hc of the magnetic disk 13 described later appears with high sensitivity. Therefore, in the present embodiment, the F2 signal, which is half the Nyquist frequency F1 of the partial response maximum likelihood detection (PRML) system, is used for level measurement in the preamble of the data portion written on the magnetic disk 13. It is used as a signal for In the level measurement of the F2 signal, the accuracy can be increased by increasing the number of measurements and averaging the level measurement values. The position where the F2 signal is written is not limited to the preamble. For example, the level measurement of the F2 signal can be realized by providing a dedicated track for writing the F2 signal and applying a format dedicated to level measurement. Further, the measurement signal is not limited to the F2 signal, and any signal in which similar signals are written in a plurality of locations may be used. For example, the preamble of the servo signal may be measured.

  Next, characteristics used in the present invention will be described. The present invention is realized by utilizing the characteristic that the coercive force Hc of a magnetic recording medium such as the magnetic disk 13 in the present embodiment varies greatly with temperature. FIG. 7 is an example of a graph showing the relationship between Hc and temperature. FIG. 8 is a diagram showing the relationship between the magnitude of Hc and the half-value width of the solitary wave. FIG. 9 is an example of a graph showing the relationship between the environmental temperature and the read signal level.

  The level of the F2 signal described above varies due to variations in the flying height of the magnetic head 15 due to atmospheric pressure, temperature variations during writing, and variations in the magnetic characteristics of the magnetic disk 13 due to temperature variations. In the present invention, among these fluctuation factors of the F2 signal level, the temperature fluctuation at the time of writing and the magnetic characteristic fluctuation (temperature fluctuation at the time of reading) are excluded by using the following characteristics, and the atmospheric pressure which is the remaining fluctuation factor is excluded. The flying height of the magnetic head 15 is controlled.

  As shown in FIG. 7, the coercive force Hc (vertical axis) of the magnetic disk 13 increases as the temperature (horizontal axis) decreases, and decreases as the temperature increases. Further, the level of the solitary wave hardly changes with respect to the change in Hc, but the half-value width Pw50 of the solitary wave changes. Further, the half-value width Pw50 of the solitary wave 302 when Hc indicated by P in FIG. 8 is large is smaller than the half-value width Pw50 of the solitary wave 301 when Hc indicated by Q is small. Furthermore, the smaller the half width Pw50, the better the resolution and the higher the signal level of the high frequency. From these facts, as shown in FIG. 9, the lower the environmental temperature (horizontal axis) of the magnetic storage device 1 is, the larger the Hc (vertical axis) of the magnetic disk 13 is. growing.

  Further, the relationship between the environmental temperature and the level of the read signal as shown in FIG. 9 is the effect of the temperature in signal writing if saturation recording is performed at any temperature during signal writing to the magnetic disk 13. Is a relationship found by determining the read signal level only by the temperature at the time of signal read.

  The magnetic storage device 1 according to the present embodiment can eliminate the influence of the temperature at the time of signal writing by writing a signal to the preamble of the magnetic disk 13 by saturation recording. Further, in the magnetic storage device 1, a read signal of a signal written in advance by saturation recording is measured for each environmental temperature, and the corresponding relationship is recorded in advance on the magnetic disk 13 as reference information. In this embodiment, the relationship between the environmental temperature and the read signal level shown in FIG. 9 is used as reference information. This reference information is created, for example, by measuring read signal levels at a plurality of temperatures under a predetermined atmospheric pressure using a thermostatic chamber and interpolating or extrapolating the measured values. The reference information may be information in which the environmental temperature and the read signal level are associated with each other.

  Next, the functional configuration of the magnetic storage device according to the present embodiment will be described. FIG. 10 is a diagram showing a functional configuration of the magnetic memory device according to the present embodiment.

  As shown in FIG. 10, the magnetic storage device 1 according to the present embodiment functions as an acquisition unit 201 (temperature acquisition unit, signal value acquisition unit), a calculation unit 202 (determination unit), and a control unit 203 (determination unit). It is prepared as. The acquisition unit 201 acquires the read signal level as the ambient temperature measured by the temperature sensor 14 and the level of the reproduction signal of the F2 signal measured by the level measurement unit 103. The calculation unit 202 determines a reference signal level at the measured environmental temperature based on the environmental temperature measured by the temperature sensor 14 and reference information stored in advance. The reference signal level is a reference signal level at each temperature, and is a signal level used as a determination reference by the control unit 203. In addition, the control unit 203 gives the heater 152 such that the difference (signal level difference) between the reference signal level at the measured ambient temperature and the read signal level measured by the level measurement unit 103 is within a predetermined range. The current is controlled. Note that these units are substantially functions realized by the MPU 11 and the memory 12.

  Next, the operation of the magnetic memory device according to this embodiment will be described. FIG. 11 is a flowchart showing an operation of basic information generation processing according to the present embodiment. This basic information generation process is a process for generating the reference information shown in FIG. 9 and is performed in advance before controlling the flying height of the magnetic head. Note that the following processing is performed at a plurality of environmental temperatures in a thermostatic chamber under a predetermined atmospheric pressure.

  First, the control unit 203 sets a predetermined bias value as the current to the heater 152 (S101). Next, the acquisition unit 201 acquires the read signal level from the level measurement unit 103 (S102), acquires the environmental temperature from the temperature sensor 14 (S103), associates them with each other, and stores them in the memory 12 (S104). The reference information is generated by interpolating or extrapolating the correspondence between other temperatures and readout signal levels based on readout signal levels at a plurality of environmental temperatures stored in association with each other in this manner.

  Next, the flying height control process will be described. FIG. 12 is a flowchart showing the operation of the flying height control process according to the present embodiment. This flying height control process is a process for controlling the flying height of the magnetic head based on the read signal level and the reference signal level.

  First, the acquisition unit 201 acquires the environmental temperature from the temperature sensor 14 (S201, temperature acquisition step), and acquires the read signal level (first signal value) from the level measurement unit 103 (S202, signal value acquisition step). Next, the calculation unit 202 determines a reference signal level (second signal value) based on the acquired environmental temperature and reference information prepared in advance (S203, determination step). Specifically, in the reference information, the signal level corresponding to the environmental temperature acquired by the acquisition unit 201 is set as the reference signal level. Next, the control unit 203 determines whether or not the difference between the read signal level and the reference signal level is within a predetermined value (S204, determination step).

  When the difference between the read signal level and the reference signal level is larger than the predetermined value (S204, NO), the control unit 203 determines whether the read signal level is larger than the reference signal level (S205, determination step).

  When the read signal level is equal to or lower than the reference signal level (S205, NO), the control unit 203 gives a set value (control amount) to the register 104 so that the current to the heater 106 increases by a predetermined amount (S206, determination step). ). That is, the flying height of the magnetic head 15 is lowered by a predetermined amount. Next, the acquisition unit 207 acquires the read signal level from the level measurement unit 103 (S207, signal value acquisition step), and the control unit 203 again determines whether the difference between the read signal level and the reference signal level is within a predetermined value. It is determined whether or not (S204, determination step).

  On the other hand, when the read signal level is higher than the reference signal level (S205, YES), the control unit 203 gives a set value to the register 104 so that the current to the heater 106 decreases by a predetermined amount (S208, determination step). That is, the flying height of the magnetic head 15 is increased by a predetermined amount. Next, the acquisition unit 201 acquires the read signal level from the level measurement unit 103 (S207, signal value acquisition step), and the control unit 203 again determines whether the difference between the read signal level and the reference signal level is within a predetermined value. It is determined whether or not (S204, determination step).

  In step S204, when the difference between the read signal level and the reference signal level is within a predetermined value (S204, YES), the control unit 20 ends the flying height control process.

  As described above, by controlling the flying height of the magnetic head 15 so that the read signal level is matched with the reference signal level measured under a predetermined atmospheric pressure, the flying height of the magnetic head 15 is increased by a fluctuation in temperature. It is kept constant against atmospheric pressure fluctuations. The timing for executing the flying height control process includes a fixed time interval by a timer, when an error occurs, when a command is received, and the like. Thus, by performing the flying height control process at an arbitrary timing, precise control can be performed.

  It is also possible to store the relationship between the fluctuation of the reference signal level and the heater current as shown in FIG. 13 as a table and set the current to be given to the heater based on this table. Specifically, in this table, the flying height is controlled to be constant by setting the heater current corresponding to the read signal level as the current applied to the heater 152.

  In the flying height control process, the environmental temperature may be periodically acquired. In the present embodiment, the heater 152 is controlled by current, but may be controlled by electric power.

Embodiment 2. FIG.
This embodiment is different from the first embodiment in the generation method of reference information. The operation of the reference information generation process according to the present embodiment that is different from the first embodiment will be described below. FIG. 14 is a flowchart showing the operation of the reference information generation process according to the present embodiment. Note that the following processing is performed at a plurality of ambient temperatures under a predetermined atmospheric pressure in a thermostatic chamber, as in the first embodiment.

  First, the control unit 203 gives a set value to the register 104 so that the current to the heater 152 increases by a predetermined amount (S301). That is, the control unit 203 reduces the flying height of the magnetic head 15 by a predetermined amount. Next, the acquisition unit 201 acquires the read signal level from the level measurement unit 103 and stores it in the memory 12 (S302). Further, the acquisition unit 201 determines whether there are a plurality of read signal levels stored in the memory 12 (S303).

  When there are a plurality of read signal levels stored in the memory 12 (S303, YES), the calculation unit 202 calculates a change in the read signal level as a differential value (S304), and determines whether the differential value is within a predetermined range. Judgment is made (S305). That is, it is determined whether or not the magnetic head 15 has contacted the magnetic disk 13 based on the amount of change.

  When the differential value is within the predetermined range (S305, YES), the calculation unit 202 stores the read signal level (final signal level) finally stored in the memory 12 in the memory 12 as TAA1 (S306). . Next, the control unit 203 gives a set value to the register 104 so that the current to the heater 152 decreases by a predetermined amount (S307). That is, the control unit 203 increases the flying height of the magnetic head 15 by a predetermined amount.

Next, the acquisition unit 201 acquires the read signal level from the level measurement unit 103 and stores it in the memory 12 as TAA2 (S308). Next, the calculation unit 202 calculates the flying height based on TAA1 and TAA2 stored in the memory 12 (S309). Specifically, the flying height is calculated by the Wallace equation shown below. In the following equation, r is the disk radial position (m), rpm is the disk rotation speed (/ min), and f is the signal frequency (Hz).
Flying height = r / f × rpm / 60 × 1n (TAA1 / TAA2)

  Furthermore, the calculation unit 202 determines whether or not the calculated flying height is equal to or greater than a predetermined amount (S310). Here, the predetermined amount includes a flying height as a design target of the magnetic storage device.

  When the flying height is equal to or greater than the predetermined amount (S310, YES), the calculation unit 202 stores TAA2 (reference signal value) in the reference information on the magnetic disk 13 (S311), and is set in association with this TAA2. The heater current is stored (S312).

  On the other hand, when the flying height is less than the predetermined amount (S310, NO), the control unit 203 again gives a set value to the register 104 so that the current to the heater 152 decreases by a predetermined amount (S307).

  In step S305, when the differential value is outside the predetermined range (S305, NO), the control unit 203 again gives a set value to the register 104 so that the current to the heater 152 increases by a predetermined amount (S301). ).

  In step S303, when there are not a plurality of signal levels stored in the memory 12 (S303, NO), the control unit 203 gives a set value to the register 104 so that the current to the heater 106 increases again by a predetermined amount. (S301).

  The above-described processing is repeated at a plurality of environmental temperatures, and the correspondence information between other environmental temperatures and signal levels is interpolated or extrapolated to generate reference information. Also, at each environmental temperature, the current applied to the heater at the time when the flying height reaches a predetermined amount (heater current, practically a set value given to the register) is saved, thereby controlling the flying height of the heater current. It can be used as an initial heater current in the process. Specifically, the heater current stored at the temperature closest to the environmental temperature acquired in step S201 in the flying height control process is set as the initial heater current, and the flying height is increased in a shorter time by increasing or decreasing the initial heater current. Can be controlled. Further, in the case of the magnetic storage device 1 having a plurality of magnetic heads 15, by performing the reference information generation processing according to the present embodiment, the flying height of all the magnetic heads 15 is a constant value with respect to the atmospheric pressure fluctuation. Alternatively, it can be maintained within a predetermined range. Further, when the flying height varies depending on the radial position of the magnetic disk 13, the area is divided by the radial position of the magnetic disk 13, and the reference information is created for each area, thereby maintaining a constant flying height in any area. can do.

Embodiment 3 FIG.
This embodiment is different from the first and second embodiments in the generation method of reference information. The present embodiment is similar to the above-described embodiment in that the measurement of the readout signal in generating the reference information is performed in a constant temperature bath at a plurality of environmental temperatures under a predetermined atmospheric pressure. The difference is that the same reference information generation processing is not performed at the temperature of. Specifically, the reference information generation process of the second embodiment is executed at a predetermined temperature, and the reference information generation process of the first embodiment is executed at other temperatures. Further, when the reference information generation process of the first embodiment is executed, the heater current stored in step S312 of the reference information generation process of the second embodiment is used. As described above, in the present embodiment, the reference information is generated by performing interpolation or extrapolation based on the read signal level acquired by the reference information generation process using a different method. In the flying height control process according to the present embodiment, the heater current obtained by the reference information generation process of the second embodiment is used as the initial heater current for all temperatures.

Embodiment 4 FIG.
In the present embodiment, the heater current is determined, that is, the flying height is determined based on the control signal level of an AGC (Automatic Gain Control) circuit instead of the read signal level. Different. Hereinafter, configurations and operations different from the above-described embodiment will be described. FIG. 15 is a diagram showing a configuration of the magnetic memory device according to the present embodiment. FIG. 16 is a block diagram showing the configuration of the AGC circuit.

  As shown in FIG. 15, the magnetic storage device 1 according to the present embodiment is different from the first and second embodiments in that an AGC circuit 16 and an A / D converter 17 are provided.

  As shown in FIG. 16, the AGC circuit unit 16 includes a GCA circuit 161 and a control signal output unit 162. The GCA circuit 161 adjusts the amplifier gain of the reproduction signal (read signal) based on the control signal output from the control signal output unit 162, and amplifies and outputs the read signal with the adjusted amplifier gain. The control signal output unit 162 generates and outputs a control signal for keeping the signal level of the read signal constant. Note that the method disclosed in Japanese Patent Application Laid-Open No. 54-091165 can be used to create a control signal by the control signal output unit 162. In the present embodiment, since it is not necessary to measure the read signal level, the head IC 10 may not include the level measuring unit 103.

  The A / D converter 17 converts the control signal output from the control signal output unit 162 into a digital value.

  In the present embodiment, the reference information is recorded on the magnetic disk 13 by measuring the control signal level instead of the read signal level at a plurality of environmental temperatures under a predetermined atmospheric pressure in the thermostatic chamber. Information. In step S202 of the flying height control process, the control signal level is acquired instead of the read signal level. In step S203, the control signal level associated with the measured environmental temperature in the reference information is determined as the reference signal level.

  Also in the reference information generation method shown in the second embodiment, the control signal level can be used instead of the read signal level.

  As described above, according to the present embodiment, the flying height of the magnetic head 15 can be determined with respect to fluctuations in atmospheric pressure based on the control signal level by the AGC circuit 16 instead of the read signal level. .

Embodiment 5 FIG.
This embodiment is different from the above-described embodiment in that the flying height is determined based on the result of Fourier transform with respect to the read signal level. Hereinafter, configurations and operations different from the above-described embodiment will be described. FIG. 17 is a diagram showing a configuration of the magnetic memory device according to the present embodiment.

  As shown in FIG. 17, the magnetic storage device 1 according to the present embodiment is different from the above-described embodiment in that the configuration includes an A / D converter 18 and a sample timing generator 19.

  The sample timing generator 19 outputs a predetermined sample timing. Based on this sample timing, the A / D converter 18 digitally converts the reproduction signal level (read signal level) output from the head IC 10 and outputs a discretized digital sampling value. Note that the sampling frequency may be at least twice the frequency of the F2 signal as the readout signal, but in this embodiment, the sampling frequency is four times the frequency of the F2 signal. The operation of the sample timing generator 19 is performed according to a method disclosed in Japanese Patent Application Laid-Open No. 2004-71060, for example.

  The calculation unit 202 performs Fourier transform on the digital sampling value signal output from the A / D converter 18 to calculate the amplitude value of the first fundamental wave of F2. For the calculation of the amplitude value, for example, a method disclosed in Japanese Patent Laid-Open No. 9-312073 is used. That is, the calculation unit 202 calculates the cosine coefficient and sine coefficient of the F2 signal component based on the digital sampling value, and calculates the square root of the sum of squares of these coefficients, thereby calculating the amplitude level (first basic fundamental) of the F2 signal. Wave amplitude level).

  Further, in the present embodiment, the reference information is calculated by the calculation unit 202 at a plurality of environmental temperatures at a predetermined atmospheric pressure in the thermostatic chamber, instead of the read signal level, at the first fundamental wave amplitude level. This is information recorded on the magnetic disk 13. In step S202 of the flying height control process, the amplitude level of the primary fundamental wave is acquired instead of the read signal level. In step S203, the amplitude level of the primary fundamental wave associated with the measured ambient temperature in the reference information is determined as the reference signal level.

  Also in the reference information generation method shown in the second embodiment, the amplitude level of the primary fundamental wave can be used instead of the read signal level.

  As described above, according to the present embodiment, the flying height of the magnetic head 15 can be determined based on the amplitude level of the primary fundamental wave calculated by the calculation unit 202 instead of the read signal level. .

  In each of the embodiments described above, the basic information is recorded in advance on the magnetic disk 13. However, for example, when the magnetic storage device 1 includes a nonvolatile memory, the basic information is stored in the nonvolatile memory. It may be recorded.

  The present invention can be implemented in various other forms without departing from the gist or main features thereof.

As mentioned above, according to this Embodiment, the technical idea shown with the following additional remarks is disclosed.
(Appendix 1) A flying height control method for controlling a flying height of the magnetic head in a magnetic storage device that records a signal on a magnetic recording medium by a magnetic head,
A temperature acquisition step of acquiring an environmental temperature that is the measured temperature of the magnetic storage device;
A signal value acquisition step of acquiring a signal value that is a value based on a signal of a predetermined frequency read from the magnetic recording medium by the magnetic head;
Information generated in advance, relationship information that indicates a correspondence relationship between the environmental temperature and a signal value under a predetermined atmospheric pressure, an acquisition temperature that is an environmental temperature acquired by the temperature acquisition step, and A flying height control method comprising: a determining step for determining a control amount for controlling the flying height of the magnetic head based on the first signal value that is the signal value acquired in the signal value acquiring step.
(Supplementary note 2) The flying height control method according to supplementary note 1,
The determining step determines a control amount of the magnetic head so that a difference between a second signal value that is a signal value corresponding to the acquired temperature in the relation information and the first signal value is within a predetermined range. A flying height control method characterized by:
(Supplementary Note 3) The flying height control method according to Supplementary Note 1 or Supplementary Note 2, wherein
In the relationship information, each of a plurality of different ambient temperatures is associated with a signal value acquired at each of the plurality of different ambient temperatures under a predetermined atmospheric pressure, and each of the associated signal values and The flying height control characterized by being generated by interpolating or extrapolating a plurality of signal values and a correspondence relationship between the environmental temperature different from the plurality of signal values and the environmental temperature based on the correspondence relationship between the environmental temperatures Method.
(Supplementary Note 4) The flying height control method according to Supplementary Note 1 or Supplementary Note 2, wherein
The relationship information includes a predetermined flying height based on a control amount of the magnetic head that the magnetic head contacts with the magnetic recording medium at a plurality of different environmental temperatures under a predetermined atmospheric pressure. Is calculated as a reference control amount, and a reference signal value that is a signal value based on the level of a signal read by the magnetic head controlled by the reference control amount, and the plurality of different environmental temperatures Correspondence between signal values and environmental temperatures that are different from the plurality of reference signal values and the environmental temperature based on the correspondence relationship between the plurality of reference signal values and the environmental temperature, respectively. A flying height control method, wherein the relationship is generated by interpolation or extrapolation.
(Supplementary Note 5) The flying height control method according to Supplementary Note 1 or Supplementary Note 2, wherein
The relationship information is based on a control amount of the magnetic head that makes contact with the magnetic recording medium at a first environmental temperature that is a predetermined environmental temperature under a predetermined atmospheric pressure. A control amount that is a flying height is calculated as a reference control amount, a reference signal value that is a signal value based on the level of a signal read by the magnetic head controlled by the reference control amount, and the first environmental temperature. Are read out by the magnetic head controlled by the reference control amount at a second environmental temperature that is at least one environmental temperature different from the first environmental temperature under the predetermined atmospheric pressure. The reference signal value is associated with the second environmental temperature, and the reference signal is based on the correspondence between the reference signal value and the first environmental temperature and the correspondence between the signal value and the second environmental temperature. And a correspondence relationship between the first ambient temperature and a correspondence relationship between the signal value and the ambient temperature different from the correspondence relationship between the signal value and the second ambient temperature are generated by interpolation or extrapolation. Quantity control method.
(Supplementary note 6) The flying height control method according to any one of supplementary notes 1 to 5,
The flying height control method according to claim 1, wherein the predetermined frequency is a half of the Nyquist frequency.
(Supplementary note 7) The flying height control method according to any one of supplementary notes 1 to 6,
The flying height control method according to claim 1, wherein the signal value is based on a preamble signal recorded on the magnetic recording medium.
(Supplementary note 8) The flying height control method according to any one of supplementary notes 1 to 7,
The flying height control method according to claim 1, wherein the signal value is a level measured by holding a peak value of a signal read from the magnetic recording medium by the magnetic head.
(Supplementary note 9) The flying height control method according to any one of supplementary notes 1 to 7,
The flying height control method, wherein the signal value is a level of a control signal for making a level of a signal read from the magnetic recording medium by the magnetic head constant.
(Supplementary note 10) The flying height control method according to any one of supplementary notes 1 to 7,
The flying height control method, wherein the signal value is a Fourier transform result of a level of a signal read from the magnetic recording medium by the magnetic head.
(Supplementary Note 11) A magnetic storage device that records a signal on a magnetic recording medium by a magnetic head and controls the flying height of the magnetic head,
A temperature acquisition unit that acquires an environmental temperature that is the measured temperature of the magnetic storage device;
A signal value acquisition unit that acquires a signal value that is a value based on a signal of a predetermined frequency read from the magnetic recording medium by the magnetic head;
Information generated in advance, relationship information that indicates a correspondence relationship between the environmental temperature and a signal value under a predetermined atmospheric pressure, an acquisition temperature that is an environmental temperature acquired by the temperature acquisition unit, and A magnetic storage device comprising: a determining unit that determines a control amount for controlling the flying height of the magnetic head based on a first signal value that is a signal value acquired by the signal value acquiring unit.
(Supplementary note 12) The magnetic storage device according to supplementary note 11, wherein
The determining unit determines a control amount of the magnetic head so that a difference between a second signal value that is a signal value corresponding to the acquired temperature in the relationship information and the first signal value is within a predetermined range. A magnetic storage device.
(Supplementary note 13) The magnetic storage device according to Supplementary note 11 or Supplementary note 12,
In the relationship information, each of a plurality of different ambient temperatures is associated with a signal value acquired at each of the plurality of different ambient temperatures under a predetermined atmospheric pressure, and each of the associated signal values and A magnetic storage device, wherein a plurality of signal values and environmental temperature correspondences different from the plurality of signal values and environmental temperature are generated by interpolation or extrapolation based on the environmental temperature correspondences .
(Supplementary note 14) The magnetic storage device according to supplementary note 11 or supplementary note 12,
The relationship information includes a predetermined flying height based on a control amount of the magnetic head that the magnetic head contacts with the magnetic recording medium at a plurality of different environmental temperatures under a predetermined atmospheric pressure. Is calculated as a reference control amount, and a reference signal value that is a signal value based on the level of a signal read by the magnetic head controlled by the reference control amount, and the plurality of different environmental temperatures Correspondence between signal values and environmental temperatures that are different from the plurality of reference signal values and the environmental temperature based on the correspondence relationship between the plurality of reference signal values and the environmental temperature, respectively. A magnetic storage device characterized in that the relationship is generated by interpolation or extrapolation.
(Supplementary note 15) The magnetic storage device according to Supplementary note 11 or Supplementary note 12,
The relationship information is based on a control amount of the magnetic head that makes contact with the magnetic recording medium at a first environmental temperature that is a predetermined environmental temperature under a predetermined atmospheric pressure. A control amount that is a flying height is calculated as a reference control amount, a reference signal value that is a signal value based on the level of a signal read by the magnetic head controlled by the reference control amount, and the first environmental temperature. Are read out by the magnetic head controlled by the reference control amount at a second environmental temperature that is at least one environmental temperature different from the first environmental temperature under the predetermined atmospheric pressure. The reference signal value is associated with the second environmental temperature, and the reference signal is based on the correspondence between the reference signal value and the first environmental temperature and the correspondence between the signal value and the second environmental temperature. And a correspondence relationship between the first ambient temperature and a correspondence relationship between the signal value and the ambient temperature different from the correspondence relationship between the signal value and the second ambient temperature are generated by interpolation or extrapolation. Storage device.
(Supplementary note 16) The magnetic storage device according to any one of supplementary notes 11 to 15,
2. The magnetic storage device according to claim 1, wherein the predetermined frequency is half the Nyquist frequency.
(Supplementary note 17) The magnetic storage device according to any one of supplementary notes 11 to 16, wherein
The magnetic storage device according to claim 1, wherein the signal value is based on a preamble signal recorded on the magnetic recording medium.
(Supplementary note 18) The magnetic storage device according to any one of supplementary notes 11 to 17,
The magnetic storage device according to claim 1, wherein the signal value is a level measured by holding a peak value of a signal read from the magnetic recording medium by the magnetic head.
(Supplementary note 19) The magnetic storage device according to any one of supplementary notes 11 to 17,
The magnetic storage device according to claim 1, wherein the signal value is a level of a control signal for making a level of a signal read from the magnetic recording medium by the magnetic head constant.
(Supplementary note 20) The magnetic storage device according to any one of supplementary notes 11 to 17,
The magnetic storage device according to claim 1, wherein the signal value is a Fourier transform result of a level of a signal read from the magnetic recording medium by the magnetic head.

1 is a diagram illustrating a hardware configuration of a magnetic storage device according to a first embodiment. It is a figure which shows the hardware constitutions of a head IC. It is a figure which shows the structure of a magnetic head. It is a figure which shows the structure of the magnetic head at the time of using a piezoelectric element. It is a figure which shows the structure of a level measurement part. It is a figure which shows the waveform of a read signal and a substantially peak voltage. It is an example of the graph which shows the relationship between Hc and temperature. It is a figure which shows the relationship between the magnitude | size of Hc, and the half value width of a solitary wave. It is an example of the graph which shows the relationship between environmental temperature and the level of a read signal. 1 is a diagram illustrating a functional configuration of a magnetic storage device according to a first embodiment. 5 is a flowchart showing an operation of basic information generation processing according to the first embodiment. 4 is a flowchart showing an operation of a flying height control process according to the first embodiment. It is a figure which shows the relationship between the fluctuation | variation of a reference signal level, and heater current. 10 is a flowchart illustrating an operation of reference information generation processing according to the second embodiment. FIG. 6 is a diagram showing a configuration of a magnetic storage device according to a fourth embodiment. It is a block diagram which shows the structure of an AGC circuit. FIG. 6 is a diagram illustrating a configuration of a magnetic storage device according to a fifth embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Magnetic storage device, 10 head IC, 11 MPU, 12 Memory, 13 Magnetic disk, 14 Temperature sensor, 15 Magnetic head, 16 AGC circuit part, 101 Read amplifier, 102 Write amplifier, 103 Level measurement part, 104 Register, 105 D / A converter, 106 heater amplifier, 201 acquisition unit, 202 calculation unit, 203 control unit.

Claims (6)

A flying height control method for controlling a flying height of the magnetic head in a magnetic storage device that records a signal on a magnetic recording medium by a magnetic head,
A temperature acquisition step of acquiring an environmental temperature that is the measured temperature of the magnetic storage device;
A signal value acquisition step of acquiring a signal value that is a value based on a signal of a predetermined frequency read from the magnetic recording medium by the magnetic head;
Information generated in advance, relationship information that indicates a correspondence relationship between the environmental temperature and a signal value under a predetermined atmospheric pressure, an acquisition temperature that is an environmental temperature acquired by the temperature acquisition step, and A flying height control method comprising: a determining step for determining a control amount for controlling the flying height of the magnetic head based on the first signal value that is the signal value acquired in the signal value acquiring step. The flying height control method according to claim 1,
The determining step determines a control amount of the magnetic head so that a difference between a second signal value that is a signal value corresponding to the acquired temperature in the relation information and the first signal value is within a predetermined range. A flying height control method characterized by: The flying height control method according to claim 1 or 2,
In the relationship information, each of a plurality of different ambient temperatures is associated with a signal value acquired at each of the plurality of different ambient temperatures under a predetermined atmospheric pressure, and each of the associated signal values and The flying height control characterized by being generated by interpolating or extrapolating a plurality of signal values and a correspondence relationship between the environmental temperature different from the plurality of signal values and the environmental temperature based on the correspondence relationship between the environmental temperatures Method. The flying height control method according to claim 1 or 2,
The relationship information includes a predetermined flying height based on a control amount of the magnetic head that the magnetic head contacts with the magnetic recording medium at a plurality of different environmental temperatures under a predetermined atmospheric pressure. Is calculated as a reference control amount, and a reference signal value that is a signal value based on the level of a signal read by the magnetic head controlled by the reference control amount, and the plurality of different environmental temperatures Correspondence between signal values and environmental temperatures that are different from the plurality of reference signal values and the environmental temperature based on the correspondence relationship between the plurality of reference signal values and the environmental temperature, respectively. A flying height control method, wherein the relationship is generated by interpolation or extrapolation. The flying height control method according to claim 1 or 2,
The relationship information is based on a control amount of the magnetic head that makes contact with the magnetic recording medium at a first environmental temperature that is a predetermined environmental temperature under a predetermined atmospheric pressure. A control amount that is a flying height is calculated as a reference control amount, a reference signal value that is a signal value based on the level of a signal read by the magnetic head controlled by the reference control amount, and the first environmental temperature. Are read out by the magnetic head controlled by the reference control amount at a second environmental temperature that is at least one environmental temperature different from the first environmental temperature under the predetermined atmospheric pressure. The reference signal value is associated with the second environmental temperature, and the reference signal is based on the correspondence between the reference signal value and the first environmental temperature and the correspondence between the signal value and the second environmental temperature. And a correspondence relationship between the first ambient temperature and a correspondence relationship between the signal value and the ambient temperature different from the correspondence relationship between the signal value and the second ambient temperature are generated by interpolation or extrapolation. Quantity control method. A magnetic storage device that records a signal on a magnetic recording medium by a magnetic head and controls the flying height of the magnetic head,
A temperature acquisition unit that acquires an environmental temperature that is the measured temperature of the magnetic storage device;
A signal value acquisition unit that acquires a signal value that is a value based on a signal of a predetermined frequency read from the magnetic recording medium by the magnetic head;
Information generated in advance, relationship information that indicates a correspondence relationship between the environmental temperature and a signal value under a predetermined atmospheric pressure, an acquisition temperature that is an environmental temperature acquired by the temperature acquisition unit, and A magnetic storage device comprising: a determining unit that determines a control amount for controlling the flying height of the magnetic head based on a first signal value that is a signal value acquired by the signal value acquiring unit.

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