JP2008226370A - Head and disk storage device having the head - Google Patents

Abstract

A highly reliable head with reduced risk of head crash and a disk storage device having the head are provided.
A head 2 having an air bearing slider surface facing a disk medium and having a write element 42 for writing data to the disk medium 1 and an element portion as a read element for reading data. The thermal expansion bodies 43a and 43b arranged at a predetermined interval from the element section, the resistance bodies 45a and 45b arranged in the vicinity of the thermal expansion body and in the vicinity of the air bearing slider surface, the element section and A heating element 46 is disposed continuously in the vicinity of the thermal expansion body and controls the spacing between the element portion and the resistor and the disk medium by heat generation.
[Selection] Figure 2

Description

  The present invention relates to a head and a disk storage device having the head, and more particularly to a technique for controlling the spacing between the head and the disk medium.

  In general, a disk storage device represented by a hard disk drive (hereinafter sometimes referred to as a disk drive) records or reproduces data on a disk medium by a magnetic head (hereinafter referred to as a head). To do. The head is mounted on the actuator, and writes or reads data in a state where it floats with respect to the disk medium surface so as to have a minute spacing (spacing).

  Incidentally, the flying height of the head, that is, the spacing between the head and the disk medium, is preferably as narrow as possible in order to improve the data recording / reproducing characteristics. On the other hand, however, a certain amount of spacing is required to prevent a collision between the head and the disk medium.

2. Description of the Related Art Conventionally, a method has been developed in which a heating element (heater) is provided in a head and the head portion is expanded (pultrusion) by the heat generation to adjust the spacing (see, for example, Patent Document 1). Here, the head has a structure having a head portion on which a read element and a write element are mounted at a front end portion of a main body called a slider. The slider is a member that floats due to air pressure generated between the rotating disk medium.
JP 2005-56447 A

  As described above, in the conventional method, the heat generation of the heating element provided in the head is controlled by the current supplied from the control circuit provided in the preamplifier circuit. However, in the above-described case, the heating element is provided directly above the read element and the write element, that is, on the side where the read element and the write element are sandwiched with respect to the air bearing slider surface. As a result, the read element and the write element protrude most from the air bearing slider surface.

  In this case, if an external impact is applied to the disk drive, there is a high possibility that the read / write element of the head will first collide with the disk medium, and a large collision (this collision is called touchdown) occurs. It can be considered that the read element and the write element are destroyed.

  Accordingly, an object of the present invention is to detect the touchdown of the head without damaging the read element or the write element while maintaining a stable head operation with a low flying height, thereby reducing the risk of head crash. An object of the present invention is to provide a highly reliable head and a disk storage device having the head.

  A head according to an aspect of the present invention has an air bearing slider surface facing a disk medium, and an element portion which is a write element for writing data to the disk medium and a read element for reading the data A thermal expansion body disposed at a predetermined interval from the element section, a resistor disposed in the vicinity of the thermal expansion body and in the vicinity of the air bearing slider surface, and the element section And a heating element arranged continuously in the vicinity of the thermal expansion body and for controlling the spacing between the element section and the resistor and the disk medium by heat generation.

  A disk storage device according to the present invention includes the head and an energization control unit for controlling the supply of power to the heating element of the head.

  According to the present invention, the thermal expansion body is disposed at a predetermined interval from the element portion, and the resistance body is disposed in the vicinity of the thermal expansion body and in the vicinity of the air bearing slider surface. By controlling so that the resistor protrudes from the air bearing slider surface rather than the element portion by heating, a structure is adopted in which the resistor contacts the disk medium before the element at the time of touchdown.

  This makes it possible to detect the touchdown of the head without damaging the read element or write element while maintaining stable head operation with a low flying height, and a highly reliable head that reduces the risk of head crashes. And a disk storage device having the same can be provided.

Embodiments of the present invention will be described below with reference to the drawings.
[First Embodiment]
FIG. 1 is a block diagram showing a main part of a disk drive according to each embodiment.
The disk drive includes a disk medium 1 that is a magnetic recording medium, a head 2, a spindle motor (SPM) 3 that rotates the disk medium 1, and an actuator 4 that is mounted on the head 2 and moves in the radial direction on the disk medium 1. And have. As will be described later, the head 2 includes a read element that performs a data read operation (reproduction operation) and a write element that performs a data write operation (record operation).

  The actuator 4 has an arm (including a suspension) on which the head 2 is mounted as a main body, and is rotationally driven by a voice coil motor (VCM) 5. The VCM 5 is driven and controlled by a VCM driver 17 included in the motor driver 15. The motor driver 15 also includes an SPM driver 16 for driving and controlling the spindle motor 3.

  The disk drive has a control / signal processing circuit system in addition to the head and disk assembly described above. The control / signal processing circuit system includes a head amplifier circuit 6, a read / write channel 10, a disk controller (HDC) 11, a microprocessor (CPU) 13, a memory 14, and a motor driver 15. Recently, it has become common to integrate several of these circuits as one IC chip.

  The HDC 11 constitutes an interface between the disk drive and the host system (personal computer or digital device) 12. The HDC 11 performs user data transfer control with the host system 12 during a read / write operation. The HDC 11 controls the read / write operation of the read / write channel 10 via a bidirectional control signal line (RWC_CTL) 27 formed of a bus interface. Further, the HDC 11 synchronizes read / write data (write data WD, read data RD) 30 of a predetermined format with the read / write channel 10 in synchronization with the write gate (WG) 28 and the read gate (RG) 29. Send and receive between them.

  Further, the HDC 11 controls the read / write operation of the head amplifier circuit 6 via a bidirectional control signal line (AMP_CTL) 21 formed of a serial interface. Further, the HDC 11 sends a gate signal WG22 to the head amplifier circuit 6. The gate signal WG22 is sent simultaneously with the write gate (WG) 28 indicating the timing of the write operation.

  When the read / write channel 10 receives the write gate (WG) 28 and the write data (WD) 30 from the HDC 11, the read / write channel 10 sends the write data (WD) 23 having a predetermined format to the head amplifier with a certain timing delay. Send to the write driver 8 of the circuit 6. At this time, the gate signal WG22 is a gate signal whose timing is adjusted by the write data (WD) 23.

  The HDC 11 sends a servo gate (SG) 31 that is a timing signal for servo control (head positioning control) to the read / write channel 10. The read / write channel 10 decodes the servo data (SD) 32 from the reproduction signal (RS) 24 that is the output signal of the read amplifier 7 at the timing of the servo gate (SG) 31 and outputs it to the HDC 11.

  The head amplifier circuit 6 includes a read amplifier 7, a write driver 8, and a heater control circuit 9. The read amplifier 7 amplifies the reproduction signal (RS) 24 read by the read element included in the head 2 and outputs the amplified signal to the read / write channel 10. The write driver 8 outputs a write current signal (WS) 25 to the write element of the head 2 in response to the gate signal WG22 from the HDC 11.

  The heater control circuit 9 is a circuit for controlling power supply to the heating elements provided in the head 2 as will be described later. The heater control circuit 9 includes a register, and the heater control signal 34 output from the HDC 11 sets the enable / disable of heat generation control and the power value in the register. The heater control circuit 9 supplies a heater current (HI) 26 based on the set power value to the heating element 46 of the head 2 in response to the input of the gate signal WG22.

  Here, the heater control circuit 9 can set different power values according to the high / low (Hi / Low) state of the gate signal WG22. That is, for example, in the high (Hi) state of the gate signal WG22, the heater control circuit 9 supplies a relatively high power to the heating element to generate heat. Further, the heater control circuit 9 may stop the power supply to the heating element according to either the high or low state of the gate signal WG22 or both.

  Further, it is possible to control any of electric power, voltage, and current value as a parameter for the heating element. In the first embodiment, the heater control circuit 9 performs control to change the power supplied to the heating element in accordance with the gate signal WG22. Depending on the configuration of the head amplifier 6, for example, a data enable line, a data input / output line, a data clock line, or a control signal line provided exclusively may be used to change the power supplied to the heating element.

  The CPU 13 is a main controller of the disk drive, and executes positioning control (servo control) of the head 2 and spacing control of the head 2. In the servo control, the CPU 13 controls the seek operation and the track following operation in accordance with the servo data SD32 reproduced from the disk medium 1. The memory 14 includes a RAM, a ROM, and a flash EEPROM, and stores a control program for the CPU 13 and various control data.

  The CPU 13 controls the drive of the VCM 5 by controlling the input value (control voltage value) of the VCM driver 17. As a result, the CPU 13 moves the head 2 mounted on the actuator 4 to a target position on the disk medium 1.

  Further, the disk drive is provided with an impact sensor (shock sensor) 18 either inside or outside the housing. When the shock sensor 18 detects an impact (disturbance) applied from the outside to the disk drive and exceeds a preset threshold value, the shock sensor 18 sends the signal to the HDC 11 through the signal line (SS) 33. The HDC 11 notifies the CPU 13 of the detection of the disturbance and outputs a write stop signal (Write Fault signal) to the host system 12. In this case, the HDC 11 sets the write gate (WG) 28 to low to prevent an unstable signal from being recorded on the disk medium 1 during application of impact.

(Head structure)
FIG. 2 is a view of the magnetic head slider 2 according to the first embodiment of the present invention as viewed from the substrate surface 41. Here, only the layer in the vicinity of the recording head main magnetic pole 42 is shown.
A pair of thermal expansion bodies 43a and 43b are installed on the same layer as the recording head main magnetic pole 42 at positions separated from each other in the track width direction. Resistors 45a and 45b are provided in the vicinity of the air bearing slider surface 44 on the thermal expansion bodies 43a and 43b via insulating films, respectively.

  Further, a heater 46 as a heating element for projecting the recording head main magnetic pole 42 and the thermal expansion bodies 43a and 43b by thermal expansion is installed on the recording head main magnetic pole 42 and the respective thermal expansion bodies 43a and 43b via an insulating film. It is. Here, the heater 46, which is a heating element, is formed so as to be particularly dense in the vicinity of the thermal expansion bodies 43a and 43b.

FIG. 3 is a diagram for explaining a second embodiment of the present invention.
The difference from FIG. 2 is that the heater 46, which is a heating element, and the resistors 45a and 45b are connected in series. With this configuration, it is not necessary to prepare a separate terminal for monitoring the resistors 45a and 45b, so that the number of terminals can be reduced.

  In the magnetic head 2 according to the second embodiment, when the heater 46 which is a heating element is energized and heated, the recording head main magnetic pole 42 and the thermal expansion bodies 43a and 43b are thermally expanded as shown in FIG. It protrudes from the bearing slider surface 44. At that time, the thermal expansion bodies 43a and 43b have a larger temperature rise, and thus the protrusion amount becomes larger.

  Therefore, in the case of a conventional magnetic head that employs a method of reducing the effective flying height by utilizing thermal expansion, the functional portion of the magnetic head (here, the recording head main pole) is recorded by the heating of the heater as a heating element. Although there is a concern that the characteristics may be deteriorated or destroyed by colliding with the surface of the disk medium, which is a medium, if the magnetic head 2 in the first embodiment and the second embodiment of the present invention is used, the heating element Due to the heating of the heater 46, the functional portion of the magnetic head 2, that is, the portion other than the recording head main magnetic pole 42, can first collide with the surface of the disk medium 1 as the recording medium.

  At the same time, by monitoring the resistance values of the resistors 45a and 45b, it is possible to detect an increase in resistance caused by a temperature increase due to frictional heat when this portion collides with the surface of the disk medium 1 as a recording medium. Thus, it is possible to detect the collision between the magnetic head 2 and the disk medium 1 as a recording medium. Accordingly, it is possible to prevent the heater 46 that is a heating element from being excessively heated, and it is possible to prevent the recording head main magnetic pole 42 that is a functional part of the magnetic head 2 from being deteriorated or destroyed.

FIG. 5 is a diagram for explaining a third embodiment of the present invention.
Here, only the layer near the reproducing head element 47 is shown. A pair of thermal expansion bodies 43a and 43b are installed in the same layer as the reproduction shield 48 at positions separated from each other in the track width direction.

  Resistors 45a and 45b are provided in the vicinity of the air bearing slider surface 44 on the thermal expansion bodies 43a and 43b via insulating films. Here, the resistors 45a and 45b are used for the reproducing head element 47. The magnetoresistive effect element is formed.

  Further, a heater 46 as a heating element for projecting the reproducing head shield 48 and the thermal expansion bodies 43a and 43b by thermal expansion is installed on the reproducing head shield 48 and the respective thermal expansion bodies 43a and 43b via an insulating film. is there. Here, the heater 46, which is a heating element, is formed so as to be particularly dense in the vicinity of the thermal expansion bodies 43a and 43b. Further, a heater 46 as a heating element and magnetoresistive effect elements as the resistors 45a and 45b are connected in series.

  In such a magnetic head 2 according to the third embodiment of the present invention, the recording is first performed by heating the heater 46 which is a heating element, similarly to the magnetic head 2 in the first and second embodiments described above. Other than the functional part of the magnetic head 2 (here, the reproducing head element 47) can collide with the surface of the disk medium 1 as a medium.

  Furthermore, by monitoring the resistances of the resistors 45a and 45b, by detecting the increase in resistance caused by the temperature increase due to frictional heat when this part collides with the surface of the disk medium 1 as a recording medium, It can be detected that the magnetic head 2 and the disk medium 1 which is a recording medium collide with each other.

  Therefore, it is possible to prevent the heater 46 that is a heat generating element from being heated excessively, and it is possible to prevent the reproducing head element 47 that is a functional part of the magnetic head 2 from being deteriorated or destroyed. Further, by using the magnetoresistive effect element formed by the resistors 45a and 45b as a resistor for collision detection, it is not necessary to separately provide a layer for the resistors 45a and 45b, so that the structure can be simplified.

FIG. 6 is a diagram for explaining a fourth embodiment of the present invention.
In this figure, the layers of the thermal expansion bodies 43 a and 43 b are provided in a layer different from the recording unit 42 and the reproducing unit 47 of the magnetic head 2. In particular, here, the thermal expansion bodies 43 a and 43 b and the resistance bodies 45 a and 45 b are provided on the leading edge side 49 of the slider 41.

  Thus, by providing the magnetic head 2 in a layer different from the recording unit 42 and the reproducing unit 47, even when the magnetic head 2 collides with the surface of the disk medium 1 as a recording medium due to atmospheric pressure fluctuation, the resistors 45a, Since it can be detected by a resistance increase of 45b, this configuration may be adopted.

(Floating height adjustment method)
FIG. 7 is a flowchart for explaining an example of a method for adjusting the flying height of the magnetic disk device using the magnetic head 2 in each embodiment of the present invention described above by heating with a heater using a resistance monitor.

  First, the magnetic disk drive is turned on (step S1), and the magnetic head slider 2 is moved to a predetermined data area (step S2). Then, the heater 46, which is a heating element, is turned on, and first, a low value current is set (step S3). Then, the resistance values of the resistors 45a and 45b are monitored to check whether a contact signal with the disk medium 1, that is, an increase in resistance due to a temperature increase due to a collision is detected (step S4).

When the contact signal is not detected (No in Step S4), the current of the heater 46 is slightly increased (Step S5), and the resistance values of the resistors 45a and 45b are monitored.
This operation is repeated until a contact signal is detected. If the contact signal can be detected (Yes in step S4), the heater current is decreased by a predetermined current value (step S5). By doing so, the effective flying height of the head 2 can be reduced by utilizing thermal expansion, and at the same time, the functional part of the magnetic head 2 due to the collision of the head 2 with the surface of the disk medium 1 as a recording medium can be obtained. Deterioration or destruction can be prevented.

  As described above, in the present embodiment, the thermal expansion body is disposed at a predetermined interval from the element portion, and the resistance body is disposed in the vicinity of the thermal expansion body and in the vicinity of the air bearing slider surface. The structure in which the resistor comes into contact with the disk medium prior to the element at the time of touchdown by controlling the resistor so that it protrudes from the air bearing slider surface rather than the element portion by heating them with a heating element. Take.

  This makes it possible to detect the touchdown of the head without damaging the read element or write element while maintaining stable head operation with a low flying height, and a highly reliable head that reduces the risk of head crashes. And a disk storage device having the same can be provided.

A thermal expansion body is disposed at a predetermined interval from the element section, a resistor is disposed in the vicinity of the thermal expansion body and in the vicinity of the air bearing slider surface, and these elements are heated by a heating element to thereby form the element section. By controlling the resistor so that it protrudes from the air bearing slider surface, the resistor contacts the disk medium prior to the element during touchdown.

  This makes it possible to detect the touchdown of the head without damaging the read element or write element while maintaining stable head operation with a low flying height, and a highly reliable head that reduces the risk of head crashes. And a disk storage device having the same can be provided.

  Note that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

The block diagram which shows the principal part of the disk drive regarding each embodiment of this invention. 1 is a cross-sectional view of a magnetic head slider according to a first embodiment of the present invention when viewed from a substrate surface. Sectional drawing which looked at the magnetic head slider which concerns on the 2nd Embodiment of this invention from the substrate surface. Sectional drawing which looked at the magnetic head slider from the substrate surface when energizing and heating the heater which is a heat generating element in the magnetic head in the 2nd embodiment of the present invention. Sectional drawing which looked at the magnetic head slider which concerns on the 3rd Embodiment of this invention from the board | substrate surface. Sectional drawing which looked at the magnetic head slider which concerns on the 4th Embodiment of this invention from the side surface. The flowchart explaining the flying height adjustment method in each embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Disk medium, 2 ... Head, 3 ... Spindle motor (SPM), 4 ... Actuator, 5 ... Voice coil motor (VCM), 6 ... Head amplifier circuit, 7 ... Read amplifier, 8 ... Write driver, 9 ... Heater control Circuits: 10: Read / write channel, 11: Disk controller (HDC), 12: Host system, 13: Microprocessor (CPU), 14: Memory, 15: Motor driver, 16: SPM driver, 17: VCM driver, 18 DESCRIPTION OF SYMBOLS ... Shock sensor, 41 ... Slider base, 42 ... Recording head, 43a, b ... Thermal expansion body, 44 ... Air bearing slider surface (ABS surface), 45a, b ... Resistance body (magnetoresistance effect element), 46 ... Heating element (Heater), 47 ... reproducing element (magnetoresistance effect element), 48 ... reproducing shield part, 49 ... lead Nguejji

Claims (9)

A head having an air bearing slider surface facing the disk medium, and having a write element for writing data to the disk medium and an element part which is a read element for reading the data;
A thermal expansion body disposed at a predetermined interval from the element portion;
A resistor disposed in the vicinity of the thermal expansion body and in the vicinity of the air bearing slider surface;
A head having a heating element that is continuously arranged in the vicinity of the element portion and the thermal expansion body and controls the spacing between the element portion and the resistor and the disk medium by heat generation. The head according to claim 1, wherein the resistor and the heating element are connected in series. The head according to claim 1, wherein the heat generating elements are formed more densely in the vicinity of the thermal expansion body than in the vicinity of the element portion. The head according to claim 1, wherein a thermal expansion coefficient of the thermal expansion body is larger than a thermal expansion coefficient of the recording element. The head according to claim 1, wherein the resistor includes a magnetoresistive effect element whose internal resistance changes due to magnetism. The element part, the thermal expansion body, and the resistor are arranged side by side on a surface that is orthogonal to the air bearing slider surface and that is orthogonal to a traveling surface of the disk medium. Described in the head. A head having an air bearing slider surface facing the disk medium, and having a write element for writing data to the disk medium and an element part which is a read element for reading the data;
A thermal expansion body disposed on the leading edge side of the head with a predetermined distance from the element portion;
A resistor disposed in the vicinity of the thermal expansion body and in the vicinity of the air bearing slider surface;
A head having a heating element for controlling the spacing between the element section and the resistor and the disk medium by heat generation. A head according to any one of claims 1 to 7;
And a power supply control means for controlling power supply to the heating element of the head. The energization control means controls the supply of electric power to the heating element such that the protruding amount of the resistor from the air bearing slider surface is larger than the protruding amount of the element portion from the air bearing slider surface. The disk storage device according to claim 8.

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