Dynamic information storage or retrieval – Storage or retrieval by simultaneous application of diverse... – Magnetic field and light beam
Reexamination Certificate
2000-01-13
2002-08-13
Korzuch, William (Department: 2653)
Dynamic information storage or retrieval
Storage or retrieval by simultaneous application of diverse...
Magnetic field and light beam
C369S112230, C369S112240, C369S044140, C369S044230, C369S300000
Reexamination Certificate
active
06434088
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention generally relates to recording and reproducing apparatus such as magnetooptical recording and reproducing apparatus using a magnetooptical head or the like. More particularly, the present invention relates to a magnetooptical head capable of reducing the diffraction limit of the spot diameter of the laser beam irradiated on a recording medium, and to a recording and reproducing apparatus capable of recording at a higher density by use of the magnetooptical head unit.
DESCRIPTION OF RELATED ART
Recently, as multimedia have become popular, a magnetooptical recording medium which is able to record and reproduce a large amount of data rapidly and at a higher density has attracted a great deal of public attention. For example, with regard to recording on a magnetooptical recording medium capable of overwrite recording, a laser beam is irradiated on the magnetooptical recording medium, while a magnetic field corresponding to input information is applied to the positions on the medium at which the laser beam has been irradiated. When this magnetooptical recording medium is reproduced, a laser beam weaker than that at the time of recording is applied to the medium, and the polarizing angle of the reflected light from the medium, which has the polarizing angle of the reflected light depending on the recording magnetization direction, is detected so that the information can be reproduced.
As to the head mechanism used in this magnetooptical recording and reproducing apparatus, an optical head
2
and a magnetic head
3
as shown in
FIG. 1
have been provided to oppose each other along their center line on both sides of a disk recording medium
1
. In this case, since each of the optical head
2
and magnetic head
3
has a large shape and weight, the heads
2
,
3
are supported by a support member
7
, and moved along the sides of the disk recording medium
1
by the rotation of a screw rotating shaft
4
driven by a drive motor
6
, so that the information can be recorded, reproduced or erased. This system has a drawback in that it has a large three-dimensional shape and a large weight. Thus, it is not suitable for small-size, light weight, large-capacity, and high-speed access for recording, reproduction and erasion which the disk recording medium and recording and reproducing apparatus are requested to have. On the other hand, a magnetooptical head mechanism
20
as shown in
FIG. 2
is known as the technology for combining the optical head
2
and magnetic head
3
into one unit, thereby reducing the size of the recording and reproducing apparatus. That is, a drive
13
for an object lens
10
of an optical head system
12
and a magnetic head/slider
14
in which a magnetic head coil
21
is provided are integrally combined. The magnetic head/slider
14
has an aperture
43
formed therethrough for focused light
32
of a laser beam
11
emitted from the optical head. The recording and reproducing apparatus using this kind of magnetooptical head is considerably small in its solid volume, but still not satisfactory enough to meet the small-size, light weight, large-capacity, and high-speed access for recording, reproduction and erasion which the disk recording medium and recording and reproducing apparatus of today are requested to have.
In addition, another system is known in which the head is secured to the tip of an arm with its fulcrum positioned around the disk recording medium. The arm is swung in parallel to the surface of the disk recording medium, thereby recording, reproducing or erasing information on or from the disk recording medium. The drive system for moving the optical head in parallel to the surface of the disk recording medium by a swing arm or linear motor is proposed in Japanese Patent Laid-open Gazette No. 5-54457. The system for driving an optical head by a swing arm is also proposed in Japanese Patent Laid-open Gazettes Nos. 8-7309 and 3-203848. Moreover, the construction having a laser beam reflecting surface formed on the magnetic head is disclosed in Japanese Patent Laid-open Gazette No. 3-280233. The problem with this system is that it is not able to achieve the suitable small size and light weight which the recording and reproducing apparatus of today is requested to have. The recording and reproducing drive capable of answering the remarkable demand for small size and high-density recording capability of a magnetooptical recording medium must be more compact, lighter in weight, and have higher-speed access for recording, reproduction and erasion. If the optical head and magnetooptical head are driven by the known swing arm system, the heads will hit the disk recording medium, causing head crash with the result that the head and disk recording medium are broken, or destroyed.
SUMMARY OF THE INVENTION
The recording and reproducing drive is required to have a small volume, be as compact as possible, make much faster access for the recording, reproduction and erasing, and have high-performance recording, reproducing and erasing functions capable of reading, recording and erasing more highly fine information signal pits, magnetic domains or domain signals on/from the recording medium than in the prior art. In addition, the head unit should be light in weight, and as a result the weight of the whole recording and reproducing drive must be light. In this connection, recording media such as magnetooptical disks are also required to have smaller diameters, light weights, higher recording capacities capable of recording at higher densities, and higher performance functions to record, reproduce and erase at a higher speed. These features have been gradually developed so far. The important thing for reducing the volume of the recording and reproducing drive is to decrease the thickness of the drive. In order to achieve this object, it is necessary that the record/reproduce head for the access to the magnetooptical disk be chiefly moved in parallel to the recording surface of the magnetooptical disk, and moved as little as possible in the perpendicular direction relative to the recording surface of the magnetooptical disk or reduce the volume to a minimum. Also, in order to make the access of the record/reproduce head to the recording medium more rapid, it is necessary to use a head mechanism capable of quick movement, and to control the record/reproduce head and magnetooptical disk to prevent collision, or crashing with each other.
Accordingly, it is an object of the invention to provide a recording and reproducing drive apparatus capable of recording, reproducing and erasing a large amount of information at high speed on/from a disk-like information recording medium that is able to record information at a high density, and particularly a recording and reproducing drive apparatus having a swing arm of which the tip end has securely mounted thereon an optical head or a magnetooptical head produced by combining an optical head and a magnetic head into a unitary body. The swing arm/head according to the invention is mounted at the fulcrum near the outer periphery of the disk recording medium loaded in the recording and reproducing drive apparatus. Thus, this swing arm/head function to pivotally move around this fulcrum in a fan shape in parallel to the recording surface of the disk recording medium, and to record/reproduce/erase information on/from the disk recording medium. The swing arm/optical head or swing arm/magnetooptical head according to the invention is a head mechanism that has the function to irradiate an extremely fine “laser beam spot” unit signal or a highly fine “magnetic field” unit signal to a small-sized high-density recording disk medium to fast record/reproduce/erase a high-density information signal such as an ultra-fine “pit” unit signal or ultra-fine “magnetic domain or domain” unit signal or to fast make information processing for record/reproduce/erase operation on this high-density information signal. The recording and reproducing apparatus of the invention has a swing arm that is formed of at le
Imai Susumu
Ishizaki Osamu
Shimazaki Katsusuke
Sugiyama Toshinori
Yoshihiro Masafumi
Birch & Stewart Kolasch & Birch, LLP
Chu Kim-Kwok
Hitachi Maxell Ltd.
Korzuch William
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