KR20090036461A - Hard disk drive having controller to control flying height of magnetic head - Google Patents

Hard disk drive having controller to control flying height of magnetic head Download PDF

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Publication number
KR20090036461A
KR20090036461A KR1020070101666A KR20070101666A KR20090036461A KR 20090036461 A KR20090036461 A KR 20090036461A KR 1020070101666 A KR1020070101666 A KR 1020070101666A KR 20070101666 A KR20070101666 A KR 20070101666A KR 20090036461 A KR20090036461 A KR 20090036461A
Authority
KR
South Korea
Prior art keywords
flying height
head
magnetic head
hard disk
disk drive
Prior art date
Application number
KR1020070101666A
Other languages
Korean (ko)
Inventor
신규식
Original Assignee
삼성전자주식회사
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 삼성전자주식회사 filed Critical 삼성전자주식회사
Priority to KR1020070101666A priority Critical patent/KR20090036461A/en
Publication of KR20090036461A publication Critical patent/KR20090036461A/en

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Classifications

    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B21/00—Head arrangements not specific to the method of recording or reproducing
    • G11B21/16—Supporting the heads; Supporting the sockets for plug-in heads
    • G11B21/20—Supporting the heads; Supporting the sockets for plug-in heads while the head is in operative position but stationary or permitting minor movements to follow irregularities in surface of record carrier
    • G11B21/21—Supporting the heads; Supporting the sockets for plug-in heads while the head is in operative position but stationary or permitting minor movements to follow irregularities in surface of record carrier with provision for maintaining desired spacing of head from record carrier, e.g. fluid-dynamic spacing, slider
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/02—Recording, reproducing, or erasing methods; Read, write or erase circuits therefor
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/48—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed
    • G11B5/58—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed with provision for moving the head for the purpose of maintaining alignment of the head relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
    • G11B5/60—Fluid-dynamic spacing of heads from record-carriers
    • G11B5/6005—Specially adapted for spacing from a rotating disc using a fluid cushion
    • G11B5/6011—Control of flying height
    • G11B5/6017—Control of flying height using capacitive measurement
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B2220/00—Record carriers by type
    • G11B2220/20—Disc-shaped record carriers
    • G11B2220/25—Disc-shaped record carriers characterised in that the disc is based on a specific recording technology
    • G11B2220/2508—Magnetic discs
    • G11B2220/2516—Hard disks

Landscapes

  • Adjustment Of The Magnetic Head Position Track Following On Tapes (AREA)
  • Supporting Of Heads In Record-Carrier Devices (AREA)

Abstract

Disclosed is a hard disk drive having a flying height control means of a magnetic head. The disclosed hard disk drive includes a magnetic head having a recording head and a playback head; A heater formed in the magnetic recording head; A flying height measuring unit measuring a flying height between the magnetic head and the disk; And a controller configured to control a current supplied to the heater coil to maintain the flying height measured from the flying height measuring unit.

Description

 Hard disk drive having controller to control flying height of magnetic head

The present invention relates to a hard disk drive, and more particularly, to a hard disk drive having means for controlling the flying height of a magnetic head.

A hard disk drive is a recording device used for storing information, and records information on concentric tracks on at least one side of the hard disk. The disk is rotatably mounted on the spindle motor, and information is accessed by a magnetic head mounted on an actuator arm that is rotated by a voice coil motor. The voice coil motor moves the magnetic head by application of a current.

The magnetic head has a recording head and a reproduction head. When a recording current is applied to the recording head, the recording head magnetizes the disk surface of the adjacent area to store information. The playhead senses the change in magnetism coming from the surface of the disc and reads the information recorded on the surface of the disc.

Since the disk of a hard disk drive rotates at high speed, the magnetic head is in direct contact with the disk, causing damage to the disk and the magnetic head. The magnetic head will fly while floating against the disk due to the dynamic air pressure generated by the disk's rotation. In this case, the height at which the magnetic head is flying is referred to as a flying height, and the flying height may be determined by a load acting in the direction of the disk by the suspension and a lift due to air flow due to the rotation of the disk.

In order to make a high capacity hard disk drive, track per inch (TPI) and bits per inch (BPI) must be increased, resulting in a narrower track width. The narrower the track, the smaller the strength of the magnetic field, and the higher the flying height, the more difficult it is to detect the magnetic field.

Therefore, in order to control flying height low, the technique which installs a heater coil in a magnetic head and controls the flying height of a magnetic head by thermal expansion has been developed.

The present invention provides a hard disk drive having a system for controlling the flying height of a magnetic head.

Hard disk drive having a system for controlling the flying height of the magnetic head according to an embodiment of the present invention,

A magnetic head having a recording head and a reproduction head;

A heater formed in the magnetic recording head;

A flying height measuring unit measuring a flying height between the magnetic head and the disk; And

And a controller configured to control a current supplied to the heater coil to maintain the flying height measured from the flying height measuring unit.

According to an aspect of the invention, the flying height measuring unit may be a capacitor measuring unit for measuring the capacitance between the disk and the magnetic head.

The capacitor measuring unit may include a capacitor measuring plate installed on an air bearing surface (ABS) formed by the recording head and the reproduction head.

According to the present invention, the capacitor measuring plate may be installed in the area of 100 ~ 500 ㎛ 2 in the ABS surface.

The capacitor measuring plate may be installed to face the recording head with respect to the playhead.

The heater may be formed in close proximity to the recording head and the reproduction head, and preferably may be formed in a coil shape.

According to the hard disk drive having the system for controlling the flying height of the magnetic head of the present invention, the flying height can be accurately controlled.

Hereinafter, the configuration and operation of the present invention will be described in detail with reference to the accompanying drawings.

 1 is a plan view illustrating an example of a hard disk drive 100 to which the present invention is applied. The disk drive 100 includes a disk 102 that is rotated by the spindle motor 104. The spindle motor 104 is mounted to the base plate 106. Actuator arm assembly 108 is also mounted to base plate 106. Actuator arm assembly 108 includes a magnetic head 110 mounted to suspension 112. Suspension 112 is attached to actuator arm 114, which can rotate in bearing assembly 116. Assembly 108 includes voice coil 118 coupled with a magnet mounted on base plate 106. Current is applied to the voice coil 118 to move the magnetic head 110 relative to the disk 102. In general, there can be one head for each disk face. The spindle motor 104, the voice coil 118 and the head 110 are connected with a plurality of electronic circuits 120 mounted on the printed circuit board 122. The electronic circuit 120 includes a play / write channel circuit, a servo driver, and a spindle motor driver. The servo driver controls the voice coil 118 to control the position of the magnetic head. The spindle motor driver controls the spindle motor 104 to control the rotation of the disk 102. The reproducing / recording channel circuit receives and transmits a recording current applied to the magnetic head from the control section, and delivers a reproduction current read from the magnetic head to the control section.

2 is a cross-sectional view illustrating a vertical magnetic head of a hard drive according to an embodiment of the present invention.

Referring to Fig. 2, the vertical magnetic head 200 includes a magnetic recording head portion W, a reproduction head portion R, and flying height control means.

The magnetic recording head portion W applies a magnetic field toward the recording medium 202 in order to record information on the recording medium (or disc) 202 spaced a predetermined distance from the air bearing surface (ABS). The main pole 210, a coil C to which a current for generating a magnetic field is applied, and a return yoke 220 forming a magnetic path of the magnetic field together with the main pole 210 is provided. The recording head portion W may further include a sub yoke 230 that helps the magnetic flux to be focused on the ABS end of the main pole 210.

The reproduction head unit R may include a magnetoresistive element 240 positioned between the two magnetic shield layers 250 and the magnetic shield layer 250 to read information recorded on the recording medium.

In FIG. 2, the coil C is illustrated in a structure surrounding the main pole 210 and the sub yoke 230 three times in the form of a solenoid. However, the shape of the coil C, the number of turns, and the like are exemplary, and any structure may be used as long as it can form a magnetic field directed to the recording medium at the ABS end of the main pole 140.

The flying height control means includes a heater 260 that locally heats the magnetic head 200, and a flying height measuring unit.

The heater 260 may be formed between the recording head and the reproduction head, but is not necessarily limited thereto. That is, the heater 260 may be formed in proximity to the recording head or the reproduction head. The heater 260 may be formed to be close to the ABS. The heater 260 may be a coil. The heater 260 receives current to generate joule's heat to cause the ABS to expand in the direction of the disk, thereby reducing the flying height FH between the ABS and the disk 202 of the magnetic head 200.

The flying height measuring unit includes a capacitor plate 270 formed to face the disk 202 on the side of the magnetic shield layer 250 on the ABS surface. The capacitor plate 270 makes it possible to measure the capacitance due to the flying height FH with the magnetic film of the disk 202. When the flying height FH becomes small, the capacitance is largely measured.

The capacitor plate 270 may be formed of a metal film, for example, a copper film or a tantalum film. By measuring the capacitance between the capacitor plate 270 and the disk 202 using a capacitor measurement circuit not shown, it is possible to measure the flying height FH between the ABS of the magnetic head and the disk 202. In particular, the flying height FH measured by the capacitor plate 270 indicates the actual flying height between the magnetic head 200 and the ABS side.

The capacitance between the capacitor plate 270 and the disk 202 is related to the area of the capacitor plate 270 in ABS, and the larger the area of the capacitor plate 270, the larger the capacitance value. The area of the capacitor plate 270 may be 100 μm 2 to 500 μm 2 . When the capacitor plate area is 100 μm 2 or less, the capacitance amount is as small as 0.01 pF, making it difficult to detect the size of the flying height FH. When the capacitor plate area is 500 μm 2 or more, the size of the magnetic head 200 can be increased.

3 is a block diagram showing some components of an electronic circuit 300 according to a preferred embodiment of the present invention. It is omitted for the servo drive and spindle motor drive well known in the art.

Referring to FIG. 3, the electronic circuit 300 includes a preamplifier 310, a play / write channel circuit 320, a controller 330, and a capacitance measurement circuit 340.

The reproduction / recording channel circuit 320 decodes the recording data input from the control unit 330 and transfers the recording data to the magnetic head 200 through the preamplifier 310 to record information on the disc. The information is transmitted to the control unit 330 via the preamplifier 320 and the reproduction / recording channel circuit 320, and the information is interpreted by the control unit 330 to decode the information.

The capacitor measuring circuit 340 transmits an electric signal measured through the capacitor plate 270 to the control unit 330, and the control unit 330 calculates a flying height corresponding to the electric signal to determine a predetermined flying height setting value. In comparison, a current for correcting the difference is applied to the heater 260 to maintain the flying height at a constant height. The control logic of the controller 330 may use well-known feedback control, PID control, and the like, and a detailed description thereof will be omitted.

The hard disk drive having the flying height control means of the magnetic head according to the present invention constantly controls the flying height between the magnetic head and the recording medium, thereby increasing the signal-to-noise ratio (SNR) and keeping the flying height low. As a result, recording performance and reproduction performance can be improved.

In addition, since the performance of the hard disk drive can be maintained uniformly, the productivity and the life of the hard disk drive can be improved.

While the foregoing has been described with reference to preferred embodiments of the present invention, those skilled in the art will be able to variously modify and change the present invention without departing from the spirit and scope of the invention as set forth in the claims below. It will be appreciated.

The hard disk drive having the flying height control means of the magnetic head according to the present invention can be usefully used in the hard disk drive industry having a vertical recording head.

 1 is a plan view illustrating an example of a hard disk drive to which the present invention is applied.

2 is a cross-sectional view illustrating a vertical magnetic head of a hard drive according to an embodiment of the present invention.

3 is a block diagram showing some components of an electronic circuit according to a preferred embodiment of the present invention.

Claims (7)

A magnetic head having a recording head and a reproduction head; A heater formed in the magnetic recording head; A flying height measuring unit measuring a flying height between the magnetic head and the disk; And And a controller for controlling a current supplied to the heater coil to maintain the flying height measured from the flying height measuring unit. The method of claim 1, The flying height measuring unit may include a capacitor measuring unit measuring a capacitance between the disc and the magnetic head. The method of claim 2, And the capacitor measuring unit includes a capacitor measuring plate provided on an ABS (air bearing surface) formed by the recording head and the reproduction head. The method of claim 3, wherein The capacitor measuring plate is a hard disk drive, characterized in that installed on the ABS surface 100 ~ 500 ㎛ 2 area. The method of claim 3, wherein And the capacitor measuring plate is installed to face the recording head with respect to the playhead. The method of claim 1, And the heater is formed in proximity to the recording head or the reproduction head. The method of claim 6, The heater is a hard disk drive, characterized in that the coil shape.
KR1020070101666A 2007-10-09 2007-10-09 Hard disk drive having controller to control flying height of magnetic head KR20090036461A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
KR1020070101666A KR20090036461A (en) 2007-10-09 2007-10-09 Hard disk drive having controller to control flying height of magnetic head

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
KR1020070101666A KR20090036461A (en) 2007-10-09 2007-10-09 Hard disk drive having controller to control flying height of magnetic head

Publications (1)

Publication Number Publication Date
KR20090036461A true KR20090036461A (en) 2009-04-14

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
KR1020070101666A KR20090036461A (en) 2007-10-09 2007-10-09 Hard disk drive having controller to control flying height of magnetic head

Country Status (1)

Country Link
KR (1) KR20090036461A (en)

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E902 Notification of reason for refusal
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