JP2008146688A - Positioning control method of recording magnetic field and magnetic recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize positioning control of a magnetic head with satisfactory accuracy at a low cost. <P>SOLUTION: The magnetic head capable of changing a distribution of a recording magnetic field is used. In the case where information is recorded to the recording medium, the magnetic head is moved onto a target recording track by an actuator, and when a difference in position between the magnetic head and the target recording track is within a prescribed range, the recording is performed by changing the distribution of the recording magnetic field outputted by the magnetic head in such a manner that the position to maximize the recording magnetic field of the magnetic head comes to the position of the target recording track (S4, S6). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a positioning control method for a magnetic recording apparatus that performs recording by a perpendicular magnetic recording method, and more particularly to a control method for positioning with a simple configuration by changing a magnetic field distribution from a magnetic head.

  There is a magnetic recording apparatus as an apparatus used for recording and reproducing information. This magnetic recording apparatus incorporates a recording disk medium such as a magnetic disk or a magneto-optical disk, and records information at a predetermined address on the recording disk medium, or reads and reproduces information therefrom. For example, in a magnetic disk device incorporating a magnetic disk medium, this address is recorded in advance as address information on the magnetic disk. By reproducing the address information from the magnetic head, information can be recorded at a predetermined address. Perform playback. An actuator is used as a positioning mechanism for moving the magnetic head to a predetermined address.

  In recent years, due to the high recording density, the space between recording tracks has narrowed, and errors have occurred in positioning with just the actuator. Therefore, Patent Document 1 proposes a two-stage actuator having a device capable of positioning at the tip of the slider as a measure for positioning accuracy in narrowing the track.

Further, in a magnetic recording apparatus, Patent Document 2 discloses a perpendicular magnetic recording head in which two opposing head cores having a small gap have the same polarity and form a sharp magnetic flux distribution using repulsion. .
JP-A-5-47126 JP-A-57-183614

  In recent years, the recording density of magnetic recording media has been improved with the increase in capacity of magnetic recording devices. To increase the recording density, it is extremely important to accurately position the magnetic head on the target track. As a future technology related to the advancement of such positioning control, Patent Document 1 proposes a two-stage actuator. However, in a two-stage actuator, there are two parts to be controlled, and each of them influences each other, so that the design is very difficult. That is, if actuators are installed at two locations for positioning the magnetic head, problems remain in terms of design and cost. First, the number of parts increases as the actuators are installed at two locations, which increases costs. Furthermore, since the probability of failure increases as the number of parts increases, a design that takes this into consideration is necessary. From the above, it is desirable that positioning can be performed accurately with one actuator without using a two-stage actuator.

  Patent Document 2 discloses a technique for forming a sharp magnetic flux distribution in a perpendicular magnetic recording head, but does not describe a technique for simply and accurately positioning the magnetic head.

  SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described problems and to realize a positioning control with high accuracy of a magnetic head with a simple configuration without using a two-stage actuator.

  In order to solve the above problems, the present invention is characterized in that in a magnetic recording apparatus, a recording magnetic field is positioned on a recording track on a recording medium by changing a recording magnetic field distribution output by a magnetic head. To do.

  This magnetic recording device detects an error to a predetermined address from address information reproduced by a magnetic head when the magnetic head is moved by an actuator on the recording medium for recording information on the recording medium. The recording magnetic field is positioned by changing the distribution of the recording magnetic field according to the error by the recording magnetic field control means. That is, the recording magnetic field control means has a position where the recording magnetic field of the magnetic head is maximized at the position of the target recording track when the difference in position between the magnetic head and the target recording track falls within a predetermined range. As described above, the distribution of the recording magnetic field output from the magnetic head is changed.

  For example, the magnetic head has two cores made of soft magnetic material and a recording head made of separate coils that excite them, and the recording magnetic field control means determines the current amount of the coils that excite the two cores. By changing, the distribution of the recording magnetic field is changed.

  Thus, in the present invention, positioning is performed by two-stage control by changing one magnetic field distribution with one actuator. For this reason, the address information on the recording medium is reproduced by the magnetic head and moved to the target track by the actuator. Furthermore, residual vibration that occurs with movement is suppressed by changing the magnetic field distribution. At this time, for example, if a recording head comprising two cores made of a soft magnetic material and separate coils for exciting them is used, it is possible to suppress the residual vibration only by changing the current.

  Since the present invention uses only one actuator, the cost is lower than using a two-stage actuator. Furthermore, it becomes difficult to break down. In addition, the design is easy because there is only one actuator.

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

  FIG. 1 shows an example of a magnetic recording head used in the embodiment of the present invention. In FIG. 1, 1 is a core, 2 and 3 are coils for generating a magnetic field, 4 is a shield, 5 is a recording medium, and 6 is a backing layer.

  The core 1 is a portion made of a soft magnetic material having a high saturation magnetic flux density Bs, and a magnetic field is generated from the tip portion by exciting this portion. The magnetic recording head used in this embodiment has a groove like the core 1 and is opposed to the groove. The core 1 is excited by the coils 2 and 3. At this time, the amount of current flowing through the coils 2 and 3 can be individually controlled by the control circuit. Further, the coil arrangement may take any form as long as the core 1 can be excited (for example, a helical coil).

  The shield 4 is a portion made of a soft magnetic material, and has an effect of securing a magnetic path and preventing the influence of an external magnetic field. The shield 4 may be physically connected to the core 1. The recording medium 5 is a medium on which information is recorded. This medium has an area in which address data is written in addition to user data. The backing layer 6 forms a magnetic path at a portion made of a soft magnetic material.

  An example of a method for positioning the recording unit by changing the magnetic field distribution using this magnetic recording head will be described. FIG. 2 shows the flow of magnetic flux when the coils 2 and 3 are excited by flowing the same amount of current (for example, 0.1 AT). FIG. 3 shows the magnetic flux density distribution on the cross section of the recording medium 5 at the time of FIG. FIG. 3 shows that the magnetic flux density is strong at the center position.

  Next, FIG. 4 shows the flow of magnetic flux when different current amounts (for example, 0.2 AT in coil 2 and 0.075 AT in coil 3) are passed through coils 2 and 3. FIG. 5 shows the magnetic flux density distribution on the cross section of the recording medium 5 at the time of FIG. At this time, it can be seen that the portion where the magnetic flux density is strong is due to the coil 2 side. That is, by adjusting the amount of current flowing through the coil, the magnetic field distribution changes, so that residual vibration in positioning can be suppressed.

  In other words, the magnetic recording head of the present embodiment has two target recording magnetic field generation units, and does not use a two-stage actuator, but only one stage of the actuator, and flows through the two recording magnetic field generation units. By changing the amount of current, the location where the magnetic field strength is the strongest is changed, and positioning control by the magnetic field is performed.

  Next, a specific positioning control method will be described. FIG. 6 shows a control flowchart.

  If you want to record on a specific track, first. The address previously written in the recording medium 5 is reproduced by a reproducing head (for example, a TMR head) (step S1). As a result, the current location of the head is known. Next, the difference between the address of the target track (hereinafter referred to as the destination) and the current location is obtained (step S2). It is determined whether or not the difference between the destination and the current location is within a predetermined magnetic field distribution changeable area (step S3). If the difference is within the magnetic field distribution changeable area, the process proceeds to step S4, and the magnetic field distribution changeable area. If not, the process proceeds to step S5.

  In step S4, recording is performed by adjusting the position of the recording magnetic field so as to maximize the recording magnetic field at the target track position by changing the magnetic field distribution without rotating the actuator.

  When the difference between the destination and the current location exceeds the range of the magnetic field distribution changeable area, in step S5, as shown in FIG. 7, the actuator is moved so that the head moves by the difference between the destination and the current location. Rotate. If the head is moved to the target track by rotating the actuator, residual vibration occurs. At this time, as shown in FIG. 8, information on whether or not the reproducing head is following the track correctly is read, and recording is performed by changing the magnetic field distribution by the vibration (step S6). As a result, recording can be performed on the target track at high speed and stably. 7 and 8, 10 represents a head, and 11 represents an arm operated by a slider and an actuator.

  The degree to which the distribution of the recording magnetic field changes by changing the currents flowing through the coils 2 and 3 shown in FIG. 1 is measured, for example, by experiment during design, and the measured values are stored in a nonvolatile memory in the magnetic recording apparatus. And can be used for current control using the value during control. The size of the magnetic field distribution changeable area is also tested at the time of design or factory shipment, and a practical value is determined and stored in, for example, a nonvolatile memory in the magnetic recording apparatus, which can be used.

  FIG. 9 is a block diagram showing the magnetic recording apparatus according to the embodiment of the present invention. When the head 10 is moved to a target track for recording information on the recording medium 5, first, the position detector 12 reads data (address information) indicating the current location from the head 10, and the current position calculation unit 13 , Calculate the current position. The position error calculation unit 14 calculates a position error based on the difference between the current position and the target position, and passes the obtained position error data to the actuator control unit 15 and the recording magnetic field control unit 16.

  The actuator control unit 15 and the recording magnetic field control unit 16 calculate respective control amounts from the position error data, control output currents to the arm 11 and the head 10 with the obtained control amounts, and the recording magnetic field of the head 10 is maximized. Is moved to the target position.

  As described above, an example of the embodiment of the present invention has been described. However, the present invention is not limited to the above-described embodiment. If the magnetic head has a mechanism capable of changing the distribution of the recording magnetic field, other structures are possible. The present invention can also be implemented in the same manner using a magnetic head.

It is a figure which shows an example of the magnetic-recording head used by embodiment of this invention. It is a figure which shows the flow of magnetic flux when two coils of a magnetic recording head are excited with the same amount of current. It is a figure which shows magnetic flux density distribution concerning the cross section of the recording medium at the time of FIG. It is a figure which shows the flow of magnetic flux when two coils of a magnetic recording head are excited with different amounts of current. FIG. 5 is a diagram showing a magnetic flux density distribution on a cross section of the recording medium at the time of FIG. 4. It is a control flowchart of positioning of a recording magnetic field. It is a figure for demonstrating positioning of a recording magnetic field. It is a figure for demonstrating positioning of a recording magnetic field. 1 is a block diagram showing a magnetic recording apparatus according to an embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Core 2, 3 Coil 4 Shield 5 Recording medium 6 Backing layer 10 Head 11 Arm 12 Position detector 13 Current position calculation part 14 Position error calculation part 15 Actuator control part 16 Recording magnetic field control part

Claims (3)

A positioning control method for positioning a recording magnetic field to a recording track on a recording medium in a magnetic recording apparatus,
The process of moving the magnetic head onto the target recording track by the actuator,
When the difference in position between the magnetic head and the target recording track falls within a predetermined range, the position where the recording magnetic field of the magnetic head is maximized is located at the position of the target recording track. And a method of changing the distribution of the recording magnetic field output from the magnetic head. In a magnetic recording apparatus comprising a magnetic head and an actuator for moving the magnetic head on a recording medium,
An actuator control means for moving the magnetic head onto a target recording track by the actuator when recording information on the recording medium;
Position error calculation means for detecting a difference in position between the magnetic head and the target recording track;
Based on the output of the position error calculation means, when the position difference between the magnetic head and the target recording track falls within a predetermined range, the recording of the magnetic head at the position of the target recording track is performed. A magnetic recording apparatus comprising: a recording magnetic field control unit that changes a distribution of a recording magnetic field output from the magnetic head so that a position where the magnetic field is maximized is reached. The magnetic recording apparatus according to claim 2,
The magnetic head has a recording head comprising two cores made of a soft magnetic material and separate coils for exciting them.
The magnetic recording apparatus, wherein the recording magnetic field control means changes the distribution of the recording magnetic field by changing a current amount of a coil excited in each of the two cores.

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