Dynamic information storage or retrieval – Storage medium structure – Optical track structure
Reexamination Certificate
2000-01-11
2004-10-26
Neyzari, Ali (Department: 2655)
Dynamic information storage or retrieval
Storage medium structure
Optical track structure
C369S275400, C369S044260
Reexamination Certificate
active
06810002
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an information storing medium, such as a magnetic disk or a magnetic tape, an optical disk, an optical card, or an optomagnetic disk, having information tracks for recording or reproducing information, and separate guide tracks for generating a tracking signal for performing tracking control. The present invention also relates to an information recording/reproducing apparatus for recording/reproducing information with respect to such an information storing medium, and to a tracking method using such an information storing medium.
2. Description of the Prior Art
FIG. 14
shows an example of the structure of a conventional magnetic tape serving as an information storing medium. Several series of information (three in
FIG. 14
) are recorded on this magnetic tape
601
. These series of information are called information tracks
602
. The spacing between an information track and its neighboring information track is called information track spacing, and is denoted as Tp. Guide tracks
603
for optical tracking control also are arranged on the magnetic tape
601
. The spacing between a guide track
603
and its neighboring guide track
603
is called guide track spacing, and is denoted as Gp. On the guide tracks
603
, grooves are arranged as tracking marks, having a suitable depth and width for being read optically.
There is a one-to-one correspondence between the guide tracks
603
and the information tracks
602
, and the values for Tp and Gp are identical. Three light beams, emitted from an optical head, form three spots
701
,
702
and
703
on the magnetic tape
601
. The three spots
701
,
702
and
703
are arranged obliquely with respect to the guide tracks
603
on the magnetic tape
601
, and are irradiated at different positions in the Y-direction. The three light beams reflected from the magnetic tape
601
return to the optical head and enter a photo-detector.
FIG. 15
is a circuit diagram showing a conventional example of obtaining a tracking signal. The photo-detectors
801
,
802
and
803
receive the light beams
704
,
705
and
706
, and output a signal corresponding to the irradiated light amount. Here, the light beam
704
corresponds to the spot
701
on the magnetic tape
601
, the light beam
705
corresponds to the spot
702
, and the light beam
706
corresponds to the spot
703
. The signals output from the photo-detectors
801
to
803
are sent to I-V amps
804
to
806
, which give out a voltage signal. The signal given out by the I-V amp
804
is called S
10
, the signal given out by the I-V amp
805
is called SMO, and the signal given out by the I-V amp
806
is called S
20
. The differential amplifier circuit
807
receives the signals S
10
and S
20
and gives out a differential signal. The signal given out by the differential amplifier circuit
807
is the tracking signal, which is given out from a terminal
808
.
This method for obtaining a tracking signal from the three light beams, is known as the three-beam method, for example in optical disk drives.
As shown in
FIG. 3
of the present invention explained below, the optical head
300
and the magnetic head
301
lie on the same base and can be moved into the Y-direction of the magnetic tape with a transfer system
302
. Based on the tracking signal obtained from the terminal
808
, the magnetic head
301
performs a tracking control so that the magnetic head
301
is positioned above the information track
602
of the magnetic tape
601
.
Recording/reproduction with other information tracks is performed by track jumping to different guide tracks.
A method for obtaining a tracking signal of high density with a conventional spot size is disclosed in Publication of Unexamined Japanese Patent Application (Tokkai) No. Hei 6-096453 (U.S. Pat. Nos. 5,406,545 and 5,650,987). In this method, the track spacing of the servo pattern region is twice the track spacing of the pit rows of the data region, two tracking signals with different phase are generated from the servo pattern region, and the product of the two tracking signals is calculated to obtain a tracking signal that is suitable for reproducing the pit rows of the data region. Consequently, the structure and the disclosed technological principle is different from the present invention.
FIG. 5
of Tokkai Hei 6-096453 is structurally similar to the present invention, but the information tracks and guide tracks of the present invention are coplanar, so that its configuration is different from the present invention.
Tokkai Hei 6-052551 contains similar disclosures as Tokkai Hei 6-96453, but its configuration and principle are different from the present invention.
The track spacing of the guide tracks is determined by the spot size of the beams irradiated from the optical head. If the spot size is not made small, there is the problem that the track spacing of the information tracks cannot be made small, and it is not possible to raise the recording density.
SUMMARY OF THE INVENTION
It is an object of the present invention to achieve higher density with a simple optical system in the optical tracking signal detection of, for example, a magnetic tape, and in light of the problems of conventional apparatuses, to provide an information storing medium with high recording density allowing reliable tracking control with conventional spot sizes, an information recording/reproducing apparatus for recording/reproducing information on such an information storing medium, and a tracking method for performing tracking control with such an information storing medium.
To achieve these objects, a first information storing medium in accordance with the present invention has a guide track and an independent information track for storing information, the information storing medium being partitioned into different kinds of zones, the guide tracks being provided with tracking marks, and the tracking marks being selectively located in the zones depending on the kind of zone.
Furthermore, to achieve these objects, a second information storing medium in accordance with the present invention is partitioned in N kinds of zones, and tracking marks in a first kind of zone are located in a first guide track and then every N tracks starting with the first guide track, i.e. on the (n·N+1)-th guide tracks (wherein n is a natural number), tracking marks in a second kind of zone are located in a second guide track adjacent to the first guide track and then every N tracks starting with the second guide track, i.e. on the (n·N+2)-th guide tracks, and in this order, tracking marks in an N-th kind of zone are located in an N-th guide track and then every N tracks starting with the N-th guide track, i.e. on the (n·N+2)-th guide tracks.
In the first and second information storing medium, it is preferable that the tracking marks are either one of concave portions and convex portions on the information storing medium.
It is also preferable that the tracking marks have a reflectivity that is different from that of another portion of the information storing medium.
It is also preferable that the information storing medium further comprises an optomagnetic recording film, wherein the tracking marks are formed in the optomagnetic recording film.
To achieve the above-mentioned objects, an information recording/reproducing apparatus in accordance with the present invention comprises:
an optical head for irradiating light onto an information storing medium having a guide track and an independent information track for storing information, wherein the information storing medium is partitioned into different kinds of zones, and tracking marks on the guide tracks are selectively located in the zones depending on the kind of zone;
a tracking signal generation means for outputting a tracking signal based on a signal that is output from the optical head;
a control means for performing tracking control based on the tracking signal; and
a recording/reproducing means for performing at least one of recor
Kadowaki Shin-ichi
Sano Kousei
Matsushita Electric - Industrial Co., Ltd.
Merchant & Gould P.C.
Neyzari Ali
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