Dynamic magnetic information storage or retrieval – Fluid bearing head support – Disk record
Reexamination Certificate
2000-07-05
2003-07-08
Nguyen, Hoa T. (Department: 2652)
Dynamic magnetic information storage or retrieval
Fluid bearing head support
Disk record
Reexamination Certificate
active
06590744
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field of the Invention
The present invention relates to a disk drive used for recording or reproducing data on or from a disk including a substrate made from a high polymer material. In particular, the present invention relates to a disk drive including a head slider having a configuration optimum to record or reproduce data on or from a disk including a high polymer substrate.
2. Description of the Prior Art
Along with the recent growth of information processing technology, it has become increasingly necessary to develop disk drives capable of realizing large recording capacities and high-speed recording/reproducing of data. In particular, magnetic disks and magneto-optical disks, which can be manufactured on large scales at low costs, are expected to be used not only for large-sized computers and personal computers, but also for devices to meet requirements of the recent multi-media age, such as image/audio communication systems, facsimile transmitters/receivers, printers, displays, image displays, and other information memories associated with various apparatuses.
Of various disk drives, such as a magnetic disk drive, a magneto-optical disk drive, and an optical disk drive, the magnetic disk drive is most popular. A configuration example of such a magnetic disk drive is shown in FIG.
1
. Referring to
FIG. 1
, the magnetic disk drive includes a housing
101
, a spindle motor
102
, and a magnetic disk
200
rotated by the spindle motor
102
. In operation of the magnetic disk drive, a head slider
104
is located at a desired position on the magnetic disk
200
by a movable actuator
103
, to allow a head mounted on the head slider
104
to write or read data on or from the magnetic disk
200
.
The housing
101
made from an aluminum alloy, a hard plastic resin, or the like has a substantially flat upper surface on which the spindle motor
102
is disposed.
The spindle motor
102
is configured as a flat brushless motor, which is driven with its angular velocity controlled at a constant value for rotating the magnetic disk
200
in the direction R
1
.
The magnetic head mounted on the head slider
104
is flied in such a manner as to face to the disk, to write or read data on or from the disk. The head slider is driven by the movable actuator
103
. A configuration of the movable actuator
103
is shown in FIG.
2
.
The movable actuator
103
shown in
FIG. 2
includes the flying type head slider
104
, an elastic member
105
for supporting the head slider
104
, an arm
106
for supporting the elastic member
105
, a vertical shaft
107
for movably supporting one end of the arm
106
, and a motor
108
for turning the arm
106
around the vertical shaft
107
.
An air flow passage, allowing flow-in/flow-out of air, is formed in the back surface of the head slider
104
and, upon rotation of the magnetic disk
200
, the head slider
104
is flied from the surface of the magnetic disk
200
with a slight spacing formed between the back surface of the head slider
104
and the front surface of the magnetic disk
200
. In such a state, data is written on or read from, that is, recorded on or reproduced from, the magnetic disk
200
by the head mounted on the head slider
104
.
The flight height of the head slider has been generally set in a range of about 0.1 &mgr;m or less; however, it tends to become gradually smaller along with the increased capacity of a magnetic disk. At present, a disk drive with the flight height reduced to a value in a range of about 20 nm to about 40 nm is being developed.
The arm
106
, which is made from a rigid material, is turned around the vertical shaft
107
to move the head slider
104
in the radial direction R
3
(see
FIG. 1
) of the magnetic disk
200
for seeking operation, so that the magnetic head mounted on the head slider
104
accesses a desired track of the magnetic disk
200
.
The motor
108
includes a voice coil
109
mounted to the other end of the arm
106
, and a magnet
110
fixed on the housing
101
. A drive voltage is supplied from an external source to the voice coil
109
, to drive the voice coil
109
in the direction R
2
.
When a drive current is supplied from an external source to the voice coil
109
, the arm
106
is turned around the vertical shaft
107
on the basis of a force generated by a magnetic field of the magnet
110
and a current flowing in the voice coil
109
. As a result, the head slider
104
mounted to the other end of the arm
106
is moved substantially in the radial direction of the magnetic disk
200
as shown by the arrow R
3
in
FIG. 1
, and the magnetic head mounted on the head slider
104
records or produces information on or from a specific track of the magnetic disk
200
.
A detailed configuration of the head slider
104
is shown in FIG.
3
. The head slider
104
retains a magnetic head
301
as a recording/reproducing element at a position close to the disk, and causes the magnetic head
301
to write or read signals on or from the disk. A surface, facing to the disk, of the head slider
104
, that is, the upper surface of the head slider
104
in
FIG. 3
has rails
302
which receive the pressure of air flowing between the head slider
104
and the disk, thereby slightly flying the head slider
104
from the disk. The related art head slider
104
is generally formed into a rectangular parallelopiped shape having a width W of 1.6 mm or more, a length L of 2.05 mm or more, and a height H of 0.43 mm or more.
FIG. 4
is a conceptual view showing a state that the head slider
104
is flied from the disk
200
for allowing the head to write or read data on or from the disk
200
, and also showing an air flow generated on the surface of the disk. The head slider
104
is supported by the elastic member
105
, which is in turn supported by the rigid arm
106
. The head
301
is fixed to the tip of the head slider
104
. The disk is rotated in the direction shown by an arrow from the arm
106
side to the head slider
104
. In this case, as shown in
FIG. 4
, an air flow based on the viscosity of air is generated on the surface of the disk, and accordingly the head slider
104
is controlled by the air flow to be slightly flied from the surface of the disk
200
, and in such a state, the head slider
104
causes the head
301
to write or read data on or from the disk
200
.
A general structure of a magnetic disk used for a magnetic disk drive will be described with reference to FIG.
5
. Referring to
FIG. 5
, the previously proposed magnetic disk
200
has an under layer
202
, a magnetic recording layer
203
, and a protective layer
204
sequentially formed on each of polished front and back surfaces of a substrate
201
made from an aluminum alloy or glass.
The substrate
201
, which has been mainly made from an aluminum alloy or glass, is to be made from a high polymer material such as polycarbonate, polyolefin, polystyrene, or poly methyl methacrylate (PMMA) and is widely available not only for magnetic disks but also for magneto-optical disks.
The disk having such a configuration differs in rigidity depending on the kind of substrate material and may cause various kinds of deformation in service environments. For example, the mounting configuration of the disk to a spindle motor by using a damper gives stress to the disk, which may cause distortion and waviness, and high-speed rotation of the disk causes the runout of the disk surface at the outer periphery. In particular, the disk including a high polymer substrate tends to cause large waviness and large runout of the disk surface.
On the other hand, as described above, the flight height of a head slider from the surface of a disk has been required to be reduced to 0.1 &mgr;m or less, and recently, to the order of about 20 nm to about 40 nm. To realize such a flight height, the surface of a disk made from an aluminum alloy or glass is polished during the manufacturing process of the disk for improving the smoothness of the surface of the disk; however, it is difficult to polish the surface
Kawazoe Kazushige
Ohuchi Hironobu
Maioli Jay H.
Nguyen Dzung C.
Nguyen Hoa T.
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