Magnetic recording medium

Details Magnetic recording medium Magnetic recording medium

1993-06-15

1998-08-04

Resan, Stevan A.

Stock material or miscellaneous articles

Structurally defined web or sheet

Continuous and nonuniform or irregular surface on layer or...

428323, 428333, 428336, 428329, 428 653, 428694BN, 428694BA, 428694BR, 428694BS, 428900, 360135, 3692753, 3692754, G11B 582, G11B 7007

Patent

active

057890625

DESCRIPTION:

BRIEF SUMMARY
TECHNICAL FIELD

This invention relates to a magnetic recording medium such for example as a flexible magnetic disk, and more particularly to a magnetic recording medium having recesses (hereinafter referred to as "magnetic head-tracking optical recesses" or "tracking optical recesses") enabling an optical tracking by a magnetic head, and still more specifically to a magnetic recording medium which comprises a substrate of a nonmagnetic material, and a magnetic layer formed on the substrate, the magnetic layer having a number of magnetic head-tracking optical recesses formed at predetermined intervals in its surface, and a data track for recording desired information thereon being formed between the magnetic head-tracking optical recess and the adjoining magnetic head-tracking optical recess.


PRIOR ART

Recently, with a wide spread of personal computers, wordprocessors and so on, external memory units used for them have been required to have a more compact design and a larger capacity. To meet these requirements, there has been proposed a flexible magnetic disk in which a reference track is formed at an innermost peripheral portion of a doughnut-like or annular recording region, and a number of magnetic head-tracking optical recesses of a ring shape are formed radially outwardly of the reference track at predetermined intervals in concentric relation to the reference track, and the annular region between the adjacent rings of magnetic head-tracking optical recesses serves as a data track (see, for example, Japanese Patent Unexamined Publication No. 2187969).
FIGS. 27 and 28 are an enlarged cross-sectional view and a plan view explanatory of a magnetic disk of this kind, respectively.
As shown in these Figures, a magnetic layer 101 is formed on a surface of a base film 100, and grooves 102 for tracking servo are formed, for example, by laser beam machining or the like to extend in a direction of rotation (i.e., circumferential direction) of the magnetic disk. A band-like region between the adjacent grooves 102, 102 serves as a data track 103 (see FIG. 30).
On the other hand, a magnetic recording/reproducing device comprises a light-emitting element (not shown) for emitting a light beam 104 for tracking servo to a surface of the above magnetic disk, and light-receiving elements 106a, 106b, 106c, 106d (see FIG. 30) for receiving reflection light 105 from the surface of the magnetic disk.
The light beam 104 emitted from the above light-emitting element is incident on the surface of the magnetic disk, and then the reflection light 105 is received by the light-receiving elements 106a, 106b, 106c, 106d.
As described above, since the grooves 102 for the tracking servo are formed in the magnetic layer 101, the intensity of the reflection light reflected on the data track 103 differs from the intensity of the reflection light reflected on the groove 102. In the example shown in FIG. 28, the tracking servo of a magnetic head (not shown) is carried out so that a sum of the outputs of the light-receiving elements 106a and 106b is equal to a sum of the outputs of the light-receiving elements 106c and 106d upon constant comparison of the two sums.
In the conventional magnetic disk, a thickness of the magnetic layer 101 is 1 to 3 .mu.m, and therefore the reflection light 105 of a desired intensity could stably be received from the surface of the magnetic disk by the light-receiving elements 106a, 106b, 106c, 106d at a level clearly different from the intensity of the reflection light from the groove 102.
However, the inventors of the present invention have found that when the thickness of the magnetic layer is rendered as thin as less than 1 .mu.m and particularly less than 0.9 .mu.m in order to improve overwrite characteristics of the magnetic disk, the intensity of the reflection on the data track is liable to become dispersed or varied i.e. not to become constant, which results in a problem that a proper tracking servo is hardly effected.
The inventors of the present invention have made variously studies on this poin

REFERENCES:
patent: 4935835 (1990-06-01), Goodwin et al.
patent: 4961123 (1990-10-01), Williams et al.
patent: 5049448 (1991-09-01), Ohya et al.
patent: 5319507 (1994-06-01), Umebayashi et al.
Database WPI, Derwent Publications, Ltd., AN-85-202382 & SU-A-1137513, Jan. 1985 (Abstract).

Affiliated with

Also associated with

Rating

Magnetic recording medium does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Magnetic recording medium, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Magnetic recording medium will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-1174987