Dynamic information storage or retrieval – Storage medium structure – Adjuncts or adapters
Reexamination Certificate
2000-03-14
2002-06-25
Cao, Allen (Department: 2652)
Dynamic information storage or retrieval
Storage medium structure
Adjuncts or adapters
Reexamination Certificate
active
06411596
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a magneto-optical disk cartridge housing a magneto-optical disk of a magnetic field modification recording system, and a magneto-optical disk apparatus in which the cartridge is put away.
2. Related Background Art
The direct overwriting type of magneto-optical disks are classified into two types: a light modulation type, and a magnetic field modulation type. The light modulation type magneto-optical disk records information by switching the magnetization direction of a magnetic layer by projection of a laser light beam modified in accordance with record signals on the magnetic layer under application of a constant auxiliary magnetic field. The magnetic field modulation type magneto-optical disk records information by switching the magnetization direction of the magnetic layer by application of an auxiliary magnetic field modified in accordance with record signals under projection of successive light or pulsed light. The light modulation type magneto-optical disk is effective in constructing a magneto-optical disk system having a high transfer rate, because of its capability of extremely high speed modulation of the laser beam. On the other hand, the magnetic field modulation type magneto-optical disk is effective in stabilization of the system and high density recording, because of the capability of stable precise pit formation without influence of skew of the disk.
As the magnetic field modulation type magneto-optical disk apparatus, information recording-reproducing apparatuses typified by minidisk apparatuses are known (called MD). FIG.
1
and
FIG. 2
illustrate the main portion of such an information recording-reproducing apparatus:
FIG. 1
is a plan view, and
FIG. 2
is a sectional view taken on line
2
—
2
in FIG.
1
. Main body
32
of magneto-optical disk cartridge
30
houses magneto-optical disk
33
rotatably. Cartridge main body
32
has aperture
37
A on its upper face for insertion of magnetic field modulation head
35
, and has another aperture
37
B on its lower face for introduction of the laser light beam emitted from optical pickup
36
. Apertures
37
A and
37
B are closable by shutters
34
A and
34
B, the shutters being movable in the direction parallel to the insertion direction of magneto-optical disk cartridge
30
.
Magnetic field modulation head
35
is held elastically by suspension
38
as an elastic holding means. This suspension
38
is fixed perpendicularly to the longitudinal direction of aperture
37
A. The one end of suspension
38
and optical pickup
36
are fixed to support
39
. Support
39
is moved perpendicularly to the direction of opening-closing of the shutters to move magnetic field modulation head
35
and optical pickup
36
together in the direction of the diameter of magneto-optical disk
33
. Arrow mark
50
shows the direction of insertion of disk cartridge
30
into magneto-optical disk apparatus
31
. This type of magneto-optical disk apparatus
31
can be made shorter in depth direction.
The above conventional magneto-optical disk apparatus
31
, although it can be made compact in the depth direction, has a disadvantage. Specifically, in the conventional magneto-optical disk apparatus
31
, the longitudinal direction of suspension
38
is perpendicular to the longitudinal direction of aperture
37
A, so that suspension
38
can be made longer even though the aperture
37
A has a small width. However, owing to the smaller length in the short direction (width direction) of aperture
37
A, suspension
38
is naturally slanted at a larger angle as shown in
FIG. 2
, whereby magnetic field modulation head
35
can be affected by positional deviation of the face of magneto-optical disk
33
, disadvantageously.
Suppose that suspension
38
is slanted at an angle of &thgr;1 to the face of magneto-optical disk
33
, and the face of magneto-optical disk
33
comes to deviate by a dimension &Dgr;Z as shown in FIG.
3
. Thereby, a core of magnetic field modulation head
35
(hereinafter also referred to as “head core”) will be displaced by &Dgr;X=&Dgr;Z×tan &thgr;1 as a lateral component. This displacement hinders precise access of the head core to a target track. In order to avoid this difficulty, the length of the head core may be made sufficiently longer to cover a larger range of the track. However, the larger length of the head core decreases magnetomotive force of the head core per unit area, resulting in a drop in the magnetic field intensity, which requires an increase in the driving current to compensate for a drop in the magnetic field. Further, the longer length of the head core causes an increase in the inductance L of the head core, an increase in impedance Z at high frequency, and an increase in power consumption and heat generation, disadvantageously.
SUMMARY OF THE INVENTION
The present invention has been made to solve the above problems of the prior art.
The present invention provides a magneto-optical disk cartridge which is less affected by deviation of the magneto-optical disk face, and can be made smaller in thickness.
The present invention also provides a magneto-otpical disk apparatus employing the above magneto-optical disk cartridge.
The magneto-optical disk cartridge of the present invention houses a magnetic field modulation type magneto-optical disk, and comprises a main body of the disk cartridge, an aperture provided on the main body of the cartridge, and a shutter for closing the aperture, wherein length W
1
of a side of the main body of the cartridge in an opening and closing direction of the shutter, length W
2
of a side of the main body of the cartridge in a direction perpendicular to the opening and closing direction of the shutter, length C
1
of the aperture in the opening and closing direction of the shutter, and length C
2
of the aperture in the direction perpendicular to the opening and closing direction of the shutter satisfy the following inequality relations:
C
1
<W
1
/2, C
2
>W
2
/2.
The magneto-optical disk apparatus of the present invention for recording and reproducing information to or from a magneto-optical disk housed in a disk cartridge having an aperture and a shutter for closing the aperture comprises an insertion opening for inserting the cartridge, a magnetic field modulation head to be inserted into the aperture to apply modulated magnetic field-to the magneto-optical disk, and an optical pickup movable together with the magnetic field modulation head to project a light beam onto the magnetooptical disk, wherein the directions of access of the magnetic field modulation head and the optical pickup to a target track of the magneto-optical disk, the direction of insertion of the magneto-optical disk cartridge, and the direction of movement of the shutter for opening and closing are parallel to each other.
REFERENCES:
patent: 5040167 (1991-08-01), Tanaka et al.
patent: 5850384 (1998-12-01), Ohmori et al.
patent: 6094326 (2000-07-01), Ikebe et al.
patent: 6215761 (2001-04-01), Goto et al.
patent: 6243355 (2001-06-01), Ikebe et al.
patent: 6269074 (2001-07-01), Funawatari et al.
patent: 6272094 (2001-08-01), Nishino et al.
patent: 6288999 (2001-09-01), Goto et al.
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