JPS63153722A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To permit recording of an upper layer without affecting the recording data of a lower layer by intersecting orthogonally the orientation directions of laminated magnetic recording layers. CONSTITUTION:The magnetic layers 2 have the two-layered structure consisting of the lower layer 2a and the upper layer 2b. The orientation directions (a), (b) of the lower layer 2a and the upper layer 2b form a specified angle to the longitudinal direction of the magnetic layer 2 and both intersect with each other at the angle theta. For example, the angle is specified to theta=90 deg. and may be any angle if is is about the angle at which the interference with each other is prevented. The coercive forces of the upper and lower layers 2b, 2a may be equal; the coercive forces are more preferably so adjusted as to be larger in the lower layer 2a than in the upper layer 2b and to have ideally about iota3 times difference therebetween. The azimuth recording meeting the orientation directions is executed by providing the upper and lower layers 2b, 2a having such intersecting orientation directions to the recording medium, by which the recording of the upper layer 2b without affecting the recording data of the lower layer 2a is permitted and the reading of the data is indepenedently executable with the respective layers.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic recording medium having a structure in which magnetic recording layers are laminated.

[Prior Art] Conventionally, in a magnetic recording medium having a two-layer structure with different coercive forces, regular data is recorded in the lower layer with high coercive force, and then dummy data is recorded in the upper layer with low coercive force.
A recording method for preventing data duplication has been proposed (Japanese Unexamined Patent Publication No. 115201/1983).

In a magnetic recording medium using such a recording method, normal data is read after dummy data in the upper layer is erased.

[Problems to be Solved by the Invention] However, in the conventional magnetic recording medium described above, even if the recording current of the four magnetic heads is changed when recording or erasing dummy data in the upper layer, the influence on the lower layer cannot be avoided. First, it has the problem of increasing the possibility of errors in legitimate data.

[Means for Solving the Problems] The magnetic recording medium according to the present invention is characterized in that the orientation directions of the stacked magnetic recording layers are substantially orthogonal.

[Function] Since the orientation directions of each layer are orthogonal in this way, by performing azimuth recording according to the orientation direction, it is possible to perform recording on the upper layer without affecting the recorded data on the lower layer. Data can also be read independently in each layer.

[Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic plan view of an embodiment of a magnetic recording medium according to the present invention.

In the figure, the magnetic layer 2 consists of a lower layer 2a and an upper layer 2b.
It has a layered structure. The orientation directions a and b of the lower layer 2a and the upper layer 2b form a constant angle with respect to the longitudinal direction of the magnetic layer 2, and both form an angle of θ. In this embodiment, 0=900, but of course it is sufficient if the angle is such that they do not interfere with each other.

Since the orientation directions are orthogonal in the upper and lower layers, the coercive forces of the upper and lower layers 2b and 2a may be the same, but the upper layer 2b and 2a may have the same coercive force.
It is desirable to make the coercive force of the lower layer 2a larger than that of b.
Ideally, there should be a difference of about 3 times.

To record data using this embodiment, data Da is first recorded in the lower layer 2a in accordance with the orientation direction a, and then data Db is recorded in the upper layer 2b in accordance with the orientation direction A, using the azimuth recording method. .

In this embodiment, since the data Da and Db can be read independently, the recording density of one magnetic layer 2 can be doubled compared to the conventional one.

Furthermore, if one of the data is used as dummy data, there is no need to erase and rewrite the dummy data as in the past when reading the regular data.

Furthermore, since both data Da and Db can be used as dummy data, it is difficult to distinguish between legitimate data even if a magnet viewer or the like is used.

FIG. 2(A) is a schematic plan view showing an example of a magnetic card using this embodiment, and FIG. 2(B) is a sectional view thereof.

In each figure, a high coercive force lower layer 2a, a low coercive force upper layer 2b, and a protective film 3 are laminated on a base material 1, and the upper and lower layers 2a and 2b constitute a magnetic layer 2. Then, data Da and Db are recorded in accordance with the orientation directions a and b of the upper and lower layers 2a and 2b, respectively. That is, 1
It is now possible to record twice as much data on one magnetic layer as before, significantly increasing the recording capacity of magnetic cards, etc., which have limited capacity.

[Effects of the Invention] As explained in detail above, in the magnetic recording medium according to the present invention, since the orientation directions of each layer are substantially orthogonal, by performing azimuth recording in accordance with the orientation direction, Recording can be performed on the upper layer without affecting recorded data, and data can also be read independently in each layer.

In this way, since there is little interference between data in each layer, data can be recorded in each layer, and twice the normal amount of data can be recorded in one data track.

[Brief explanation of the drawing]

FIG. 1 is a schematic plan view of one embodiment of a magnetic recording medium according to the present invention, FIG. 2(A) is a schematic plan view showing an example of a magnetic card using this embodiment, and FIG. B) is a sectional view thereof. 1. Middle substrate 2... Magnetic layer 2aφ... Lower layer 2b... Upper layer 3. Protective film a... Orientation direction of lower layer b... Orientation direction of upper layer Da, Db... Data

Claims (1)

[Claims] (1) A magnetic recording medium characterized in that the orientation directions of the stacked magnetic recording layers are substantially orthogonal.