Dynamic magnetic information storage or retrieval – Head mounting – Disk record
Reexamination Certificate
2000-08-09
2002-10-15
Heinz, A. J. (Department: 2652)
Dynamic magnetic information storage or retrieval
Head mounting
Disk record
Reexamination Certificate
active
06466411
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a magnetic head device mounted on, for example, a magneto-optical disk apparatus and, more particularly, to a magnetic head device capable of minimizing a sway of a head body which is parallel to a surface of a recording medium, and permitting easy application of load to the head body toward the recording medium.
2. Description of the Related Art
FIG. 6
is a top plan view showing a conventional magnetic head device, and
FIG. 7
is a side view of the magnetic head device of FIG.
6
.
In the magnetic head device shown in
FIGS. 6 and 7
, a proximal end portion
1
c
of a load beam
1
, which is a supporting member, is fixed to a carriage
2
, which is a rigid member, via fixing holes
1
e
and
1
e
. A head body
3
is attached to a distal end portion
1
d
of the load beam
1
via a flexure. For the purpose of clarity, the flexure is not shown in
FIGS. 6 and 7
.
The load beam
1
is formed of a leaf spring. In the load beam
1
, rails
1
a
and
1
a
, which are rigid, are formed on both sides from a vicinity of a distal end thereof to a vicinity of the proximal end portion
1
c
. Leaf spring portions
1
b
and
1
b
, which are free of the rails
1
a
and
1
a
and have low rigidity, are provided between terminals of the rails
1
a
and
1
a
and the proximal end portion
1
c
. The load beam
1
is bent by a predetermined angle &thgr; at flexed portions
1
b
1
and
1
b
1
of the leaf spring portions
1
b
and
1
b
, the distal end portion
1
d
of the load beam
1
being close to a recording medium
4
.
The magnetic head device shown in
FIGS. 6 and 7
is used to provide, for example, a vertical magnetic field for recording in a magneto-optical disk apparatus.
The recording medium
4
of a magneto-optical disk apparatus is protected by a cartridge
5
made of a plastic constituent or the like. Hence, the load beam
1
sets the head body
3
over a front surface
4
a
of the recording medium from above an opening
5
a
, extending over the cartridge
5
located between the carriage
2
and the opening
5
a
of the cartridge
5
.
The head body
3
is subjected to an air flow generated as the recording medium
4
rotates, and lifts for a predetermined lifting distance.
FIG. 8
is a side view of an enlarged portion of a neighborhood of the lifting head body
3
.
The head body
3
includes a center core
3
b
and side cores
3
c
and
3
c
formed of a magnetic material, such as ferrite, that are installed in a cutout of a slider
3
a
formed of a nonmagnetic material, such as a ceramic constituent. A coil
3
d
is wound around the center core
3
b
. Bottom surfaces of the center core
3
b
and the side cores
3
c
and
3
c
are flush with a bottom surface of the slider
3
a
. A back core
3
e
made of a magnetic material, such as ferrite, is installed on top surfaces of the slider
3
a
, the center core
3
b
, and the side cores
3
c
and
3
c
. The head body
3
is supported by the load beam
1
via a flexure
6
joined to the back core.
A pivot
1
f
serving as a pivoting support point of the head body extends toward the recording medium
4
from a distal end portion
1
d
of the load beam
1
. The pivot
1
f
is abutted against the top surface of the head body
3
via the flexure
6
to pivotally support the head body
3
.
In the head body
3
, when the coil
3
d
is energized, a closed magnetic path including the center core
3
b
, the back core
3
e
, and the side cores
3
c
and
3
c
is formed, and a vertical magnetic field is applied from the center core
3
b
to the recording medium
4
. Energy of a laser beam
7
is applied to a rear surface
4
b
of the recording medium to record signals onto the recording medium
4
by magnetic modulation or optical modulation.
The recording medium
4
sometimes vertically teeters while rotating. The lifting distance of the head body
3
is set to a predetermined value, and the head body
3
is adapted to vertically move also. The head body
3
is able to move according to the vertical dislocation of the recording medium
4
because the load beam
1
is allowed to vertically teeter around the flexed portions
1
b
1
and
1
b
1
of the leaf spring portions
1
b
and
1
b.
The conventional magnetic device as shown in
FIGS. 6 and 7
, however, has been posing a problem in that the head body
3
is significantly dislocated in a direction parallel to the front surface
4
a
of the recording medium when the head body
3
moves according to the vertical teeter of the recording medium
4
.
When the load beam
1
vertically teeters around the flexed portions
1
b
1
and
1
b
1
, the pivot
1
f
, which is in contact with the top surface of the head body
3
to support the head body
3
so that it is allowed to teeter, moves along an arc A, having the flexed portion
1
b
1
shown in
FIG. 9
as a center thereof. When the pivot
1
f
vertically moves by R on the arc A, a teetering distance of the pivot
1
f
in a direction X of
FIG. 9
which is parallel to the front surface
4
a
of the recording medium is denoted by L.
In recent years, because of an increasing trend toward reducing a thickness of the recording medium
4
, the vertical dislocation of the recording medium
4
during rotation is increasing. Accordingly, a teetering distance R of the pivot
1
f
in direction A of the arc and a teetering distance L in the direction parallel to the front surface
4
a
of the recording medium are increasing.
The teetering distance L in the direction parallel to the front surface
4
a
of the recording medium of the pivot
1
f
must be controlled to a certain range wherein the center core
3
b
shown in
FIG. 8
stays in an area of the recording medium
4
where the center core
3
b
is activated by the energy of the laser beam
7
. However, mainly due to a trend toward higher recording density of optical disk devices, there has been a demand for reducing a width W
1
of the center core
3
b
, which requires the teetering distance L of the pivot
1
f
be further shortened.
To minimize the teetering distance L in the direction parallel to the front surface
4
a
of the recording medium when the teetering distance R of the pivot
1
f
in the circumferential direction remains unchanged, an arrangement must be made so that the pivot
1
f
vertically moves about an intersection A
1
of a straight line that passes the flexed portion
1
b
1
serving as the teeter support point of the load beam
1
and is parallel to the front surface
4
a
of the recording medium, and the arc A.
In the conventional magnetic head device, however, the head body
3
is set on the recording medium
4
through the opening
5
a
of the cartridge
5
, which protects the recording medium
4
as illustrated in
FIGS. 6 and 7
. Hence, the head body
3
is positioned below the flexed portion
1
b
1
of the load beam
1
. Especially because the load beam
1
extends in the X-direction of
FIG. 6
, in which the recording medium
4
rotates, so as to set the head body
3
on the recording medium
4
as shown in
FIGS. 6 and 7
, a total length of the load beam
1
increases, and a height difference H between the pivot
1
f
and the flexed portion
1
b
1
of the load beam
1
increases. As a result, the teetering distance L in the direction parallel to the front surface
4
a
of the recording medium when the pivot If vertically moves by R on the arc A increases. Hence, it has been increasingly becoming difficult for the conventional magnetic head device to meet the demand for reducing the thickness of the recording medium
4
and the core width of the center core
3
b
of the head body
3
.
Furthermore, as the total length of the load beam
1
increases, the load beam
1
will be more susceptible to vibrations or the like, and it will be difficult to accomplish assembly accuracy.
When the recording medium
4
is at rest, the head body
3
need to be pressed against the front surface
4
a
of the recording medium by a pressing force from the load beam
1
. To obtain the pressing force, the leaf spring por
Alps Electric Co. ,Ltd.
Brinks Hofer Gilson & Lione
Heinz A. J.
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