Dynamic information storage or retrieval – Storage or retrieval by simultaneous application of diverse... – Magnetic field and light beam
Reexamination Certificate
1998-03-13
2002-06-11
Neyzari, Ali (Department: 2653)
Dynamic information storage or retrieval
Storage or retrieval by simultaneous application of diverse...
Magnetic field and light beam
C369S013170, C369S053280
Reexamination Certificate
active
06404705
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a magneto-optical disk apparatus and a position adjustment method of a head mechanism which is mounted in the magneto-optical disk apparatus. More particularly, the present invention relates to the magneto-optical disk apparatus which is preferable to improvement of a recording frequency and the position adjustment method of a head mechanism which is arranged to adjust a relative position of a magnetic head against an optical head, both of which heads are mounted in the magneto-optical disk apparatus.
Like a magnetic disk such as a floppy disk, the magneto-optical disk has been heretofore put into practice as an information recording medium from or on which information may be repetitively recorded, reproduced and erased. This magneto-optical disk is arranged to magnetically record data on a magnetic layer by virtue of an external magnetic field with heat caused by a laser beam. The magneto-optical disk apparatus for this type of magneto-optical disk generally includes an optical head for focusing a laser beam as a beam spot on the magnetic layer of the magneto-optical disk and a magnetic head for applying an external magnetic field onto the magnetic layer, the magnetic head located as opposed to the optical head.
The laser beam spot applied onto the magnetic layer has a diameter of 1 to 3 &mgr;m, while the main magnetic pole composing the magnetic head is sized to be as large as 100 to 300 &mgr;m. In this composition, it has been enough to position the magnetic head in the specific range of the laser beam target section where the necessary magnetic field for recording or erasing information may be applied without having to strictly match the axial center of the main magnetic pole to the optical axis of the optical head.
Hereafter, the description will be oriented to the construction of the head mechanism of the conventional magnetic-optical disk apparatus and the adjustment method of the magnetic head against the optical axis of the optical head with reference to
FIGS. 7A and 7B
showing the plan view and the front view.
As shown in
FIGS. 7A and 7B
, the optical head
1
is mounted at one tip of an arm
3
formed in a horseshoe manner and the magnetic head
2
is mounted at the other tip of an arm
3
. The optical head
1
is opposed to the magnetic head
2
. The optical head
1
is secured to a lower arm
3
a
with an objective lens
1
a
directed upward. The objective lens
1
a
provides an actuator (not shown) for auto-focusing and tracking control. By operating the actuator, it is possible to properly change the position of the laser beam spot. On the other hand, the magnetic head
2
is mounted on a slider
4
. The slider
4
is mounted on the upper end of the arm
3
with a gimbal spring
5
laid therebetween.
The gimbal spring
5
is fixed on the upper end of the arm
3
by means of a screw
6
. The gimbal spring
5
has a through hole
5
a
whose diameter is far larger than that of the screw
6
. Hence, a larger washer (not shown) than the through hole
5
a
is fitted into the through hole
5
a
. Before fastening the screw, the setting position of the magnetic head
2
against the optical head (more strictly, the objective lens
1
a
) may be adjusted in the allowance range. Further, the arm
3
is linearly moved in the radial direction of the magneto-optical disk
7
by means of the driving device (not shown). Or, the arm
3
is driven arcuately so that the head setting section is moved substantially in the radial direction of the magneto-optical disk
7
with the arm end linked at the given position of the magneto-optical disk apparatus as a supporting point.
In this construction, the adjustment of the setting position of the magnetic head
2
is carried out by mounting the magneto-optical disk
7
to the magneto-optical disk apparatus and repeating the recording of information on the magneto-optical disk
7
and the reproduction of information therefor. That is, when the assembly of the magneto-optical disk apparatus is terminated, the magneto-optical disk
7
is mounted to the magneto-optical disk apparatus so that the magnetic head
2
operates to generate a magnetic field of a predetermined recording intensity as the optical head
1
is applying a laser beam of a recording intensity, for recording information on the magneto-optical disk
7
. Next, the drive of the magnetic head
2
is stopped and then the intensity of the laser beam applied from the magneto-optical disk
7
is switched into a reproducing intensity on which the recorded information is reproduced. If the output of the reproduction signal detected by the optical head
1
does not reach a predetermined value, it is grasped that the external magnetic field of the predetermined intensity is not applied to the magnetic layer because of the improper setting position of the magnetic head
2
. Then, the mounting location of the gimbal spring
5
against the upper arm
3
b
is changed by loosening the screw
6
. Until the reproduction signal reaches the output of the predetermined value or more, the foregoing operations are repeated.
In the field of the magneto-optical recording, one of the most significant technical issues is improvement of a recording frequency. For improving the recording frequency, it is indispensable to reduce the magnetic head
2
in size. The reduced magnetic head
2
leads to narrowing the distribution of a magnetic field generated by the magnetic pole, which needs to more precisely position the magnetic head
2
against the optical axis of the optical head.
However, the conventional mechanism for adjusting the position of the magnetic head does not provide a fine adjustment mechanism for the magnetic head. It means that the conventional adjustment mechanism has difficulty in positioning the magnetic head
2
against the optical axis of the optical head with precision, so that the position adjustment of the magnetic head is not made high-efficient. Moreover, the foregoing conventional adjustment method of the magnetic head needs to actually record information on the magneto-optical disk, which may suffer from erroneous erasion of information to be saved.
SUMMARY OF THE INVENTION
The present invention is made to overcome the foregoing difficulties, and it is an object of the present invention to provide a magneto-optical disk apparatus and an adjustment method of a head mechanism which are arranged to strictly and quickly adjust the setting position of a magnetic head against an optical axis of an optical head.
In order to overcome the foregoing difficulties, according to the invention, at first, a magneto-optical disk apparatus for locating an optical head for focusing a laser beam as a beam spot on a magnetic layer of each side of the magneto-optical disk as opposed to the magnetic head for applying an external magnetic field on the magnetic layer is constructed to provide a fine adjustment mechanism for adjusting the setting position of the magnetic head against the optical axis of the optical head in an arm mechanism for holding the magnetic head.
As the fine adjustment mechanism, there may be considered a member containing a gimbal spring in parallel to the magnetic head and the slider is slidably mounted with the arm mechanism so that the member may be slid by the arm mechanism. This type of fine adjustment mechanism of the magnetic head allows the magnetic head to move in the desired direction step by step. Hence, this type of fine adjustment mechanism enables to adjust the setting position of the magnetic head against the optical axis of the optical head more quickly and precisely than the conventional adjustment mechanism in which the setting position of the magnetic head is changed by using a clearance of the screw through hole opened in the gimbal spring.
Second, like the above, the magneto-optical disk apparatus is constructed to mount a plurality of magnetic heads adjacently to one slider and provide a head driving device for individually driving these magnetic heads.
The mount of these magnetic heads adjacen
Ohta Norio
Suenaga Masashi
Watanabe Hitoshi
Hitachi Maxell Ltd.
Neyzari Ali
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