HEAD STACK ASSEMBLY, HARD DISK DRIVE COMPRISING THE HEAD STACK ASSEMBLY, AND METHOD TO REDUCE OFF-TRACK IN THE HARD DISK DRIVE

1 . A head stack assembly comprising:

a swing arm rotatably mounted on a base member of a hard disk drive;

a connecting plate coupled to a front edge of the swing arm;

a suspension coupled to the connecting plate;

a pair of hinges, one located on each side of a center line of the suspension to connect the connecting plate to the suspension;

a piezoelectric material layer including a piezoelectric material located on only a first hinge of the pair of hinges, wherein the first hinge is closer than a second hinge of the pair of hinges to a center of a disk in the hard disk drive; and

a head slider mounted on the front edge of the suspension.

2 . The head stack assembly of claim 1 , wherein when a voltage is applied to the piezoelectric material layer, the piezoelectric material layer compresses the first hinge to bend the first hinge toward a surface of the disk.

3 . The head stack assembly of claim 1 , wherein the piezoelectric material layer is formed by adhering a film including the piezoelectric material onto the first hinge.

4 . The head stack assembly of claim 1 , wherein the piezoelectric material is lead zirconate titanate (PZT).

5 . A hard disk drive comprising:

a base member;

a disk that is a data storage medium to rotate on the base member at a high speed; and

a head stack assembly rotatably mounted to the base member to record data into the disk or to reproduce data stored in the disk, the head stack assembly comprising:

a swing arm rotatably mounted on a base member of a hard disk drive;

a connecting plate coupled to a front edge of the swing arm;

a suspension coupled to the connecting plate;

a pair of hinges, one located on each side of a center line of the suspension to connect the connecting plate to the suspension;

a piezoelectric material layer including a piezoelectric material located on only a first hinge of the pair of hinges, wherein the first hinge is closer than a second hinge of the pair of hinges to a center of a disk in the hard disk drive; and

a head slider mounted on the front edge of the suspension.

6 . The HDD of claim 5 , further comprising:

an off-track detection unit to detect off-track of the head slider; and

a voltage adjusting unit to adjust a magnitude of voltage applied to the piezoelectric material layer in proportion to a degree of the off-track detected by the off-track detection unit.

7 . A method to reduce off-track in a hard disk drive, the method comprising:

moving a head slider onto a certain track of a disk of the hard disk drive to record data onto the track or to reproduce data from the track;

detecting a degree of off-track by using an off-track detection unit;

adjusting a magnitude of voltage to be applied to the piezoelectric material layer by using a voltage adjusting unit in proportion to the degree of the off-track detected by the off-track detection unit; and

applying the voltage to the piezoelectric material layer.

8 . A hard disk drive, comprising:

a disk;

a magnetic head to write to or read from the disk, the magnetic head including a first side and a second side opposite the first side, the first side being closer to a center of the disk than the second side, and

an actuator to tilt the first side of the magnetic head closer to a surface of the disk than the second side of the magnetic head.

9 . The hard disk drive according to claim 8 , wherein the actuator comprises at least one hinge having a piezoelectric layer located thereon to actuate the hinge.

10 . The hard disk drive according to claim 9 , wherein the piezoelectric layer is located on a first surface of the hinge facing the disk.

11 . The hard disk drive according to claim 9 , wherein the at least one hinge comprises a first hinge and a second hinge, the first hinge located closer to a center of the disk than the second hinge, and

the piezoelectric material is located only on a first surface of the first hinge, the first surface facing a surface of the disk.

12 . The hard disk drive according to claim 9 , wherein the at least one hinge comprises a first hinge and a second hinge, the first hinge located closer to a center of the disk than the second hinge, each of the first and second hinges having a first surface facing the disk and a second surface opposite the first surface,

a first layer of piezoelectric material is located on the first surface of the first hinge, and

a second layer of piezoelectric material is located the second surface of the second hinge.

13 . The hard disk drive according to claim 9 , further comprising:

a base member to receive the disk and a head stack assembly thereon, the head stack assembly comprising:

a swing arm having a first end rotatably attached to the base;

the at least one hinge connected to a second end of the swing arm opposite the first end; and

a suspension having a first end connected to the second end of the swing arm via the hinge and having the magnetic head mounted on a second end of the suspension opposite the first end of the suspension, wherein the disk is rotatably attached to the base member.

14 . The hard disk drive according to claim 13 , further comprising:

a vibration detection unit to detect vibration of the disk; and

a voltage adjustment unit to adjust a voltage applied to the actuator when an off-track is detected.

15 . The hard disk drive according to claim 14 , wherein the vibration detection unit is an off-track detection unit to detect an off track of the magnetic head.

16 . A method to reduce off-track of a hard disk drive, the method comprising:

tilting a magnetic head to read to or write from a disk so that a first side of the magnetic head is closer to a surface of the disk than a second side opposite the first side,

wherein the first side of the magnetic head is closer to a center of the disk than the second side.

17 . The method according to claim 16 , further comprising:

detecting an off-track of the magnetic head and tilting the magnetic head when an off-track is detected.

18 . The method according to claim 16 , further comprising:

detecting a vibration of the disk and tilting the magnetic head when vibration of the disk is detected.

19 . The method according to claim 18 , wherein the magnetic head is tilted only when a vibration is detected.

20 . The method according to claim 18 , wherein a tilt angle of the magnetic head is adjusted according to a magnitude of a detected vibration.

21 . The method according to claim 18 , wherein the tilt angle of the magnetic head is maintained at a constant angle regardless of a magnitude of detected vibration.

22 . The method according to claim 16 , wherein tilting the magnetic head comprises adjusting an actuator.

23 . The method according to claim 22 , wherein the actuator comprises a piezoelectric layer on a hinge, and

tilting the magnetic head comprises applying a voltage to the piezoelectric layer.

24 . The method according to claim 22 , wherein the actuator comprises first and second hinges, each having a first surface facing the disk and a second surface opposite the first surface, the first hinge being closer to a center of the disk than the second hinge, and

adjusting the actuator comprises bending the first hinge toward the disk.

25 . The method according to claim 24 , wherein a first piezoelectric layer is located on the first surface of the first hinge, and

bending the first hinge comprises applying a voltage to the first piezoelectric layer.

26 . The method according to claim 25 , wherein a piezoelectric layer is located only on the first hinge of the first and second hinges.

27 . The method according to claim 26 , wherein a second piezoelectric layer is located on the second surface of the second hinge, and

adjusting the actuator comprises applying a voltage to the first and second piezoelectric layers.

28 . A computing unit, comprising:

a hard disk drive, comprising:

a disk,

a magnetic head to write to or read from the disk, the magnetic head including a first side and a second side opposite the first side, the first side being closer to a center of the disk than the second side, and

an actuator to tilt the first side of the magnetic head closer to a surface of the disk than the second side of the magnetic head;

a controller to control read and write operations from and to the disk; and

an interface to operate the controller to perform read and write operations.

29 . The computing unit according to claim 28 , wherein the interface includes at least one of a data transfer port, a sensory display, and a data input interface.

30 . The computing unit according to claim 29 , wherein the data input interface includes at least one of a button, a keypad, a keyboard, scroll wheel, a joystick, and a switch.

31 . The computing unit according to claim 28 , wherein the actuator comprises at least one hinge having a piezoelectric layer located thereon to actuate the hinge.

32 . The computing unit according to claim 31 , further comprising:

a vibration detection unit to detect vibration of the disk; and

a voltage adjustment unit to adjust a voltage applied to the piezoelectric layer when a vibration is detected.

33 . The computing unit according to claim 31 , wherein the at least one hinge comprises a first hinge and a second hinge, the first hinge located closer to a center of the disk than the second hinge, and

the piezoelectric material is located only on a first surface of the first hinge, the first surface facing a surface of the disk.