JPH0646498B2 - Magnetic bubble expander - Google Patents

Description

The present invention relates to a magnetic bubble expander, and more particularly to a magnetic bubble expander for expanding magnetic bubbles.

[Background of the Invention]

Magnetic bubble expanders are commonly used in magnetic bubble memory devices in combination with magnetic bubble detector lines that convert the magnetic bubbles into electrical signals. Usually, in order to obtain a large electric signal from the magnetic bubble detector line, a method of expanding the magnetic bubble into a string-shaped bubble of 200 to 500 times and detecting the expanded magnetic bubble in the magnetic bubble detector line is used. The magnetic bubble expander according to the present invention expands the magnetic bubble into a string-like bubble in this manner.

FIG. 1 is a plan view of an essential part when this magnetic bubble expander is used in combination with a magnetic bubble detector. In the figure, S is a magnetic bubble expander, and D is a magnetic bubble detector line for detecting the string-like bubbles expanded by the magnetic bubble expander S. The patterns of the magnetic bubble expander S and the magnetic bubble detector line D are formed of a soft ferromagnetic material such as permalloy. Also, in the figure, H
_R is a magnetic field applied to rotate the magnetic bubble expander S and the magnetic bubble detector line D in the pattern plane to transfer the magnetic bubble in the direction of arrow p, and H _B acts in the direction perpendicular to the pattern plane. Is a magnetic field applied to make magnetic bubbles stably exist, and both of these magnetic fields are applied from the outside.

In such a configuration, the rotating magnetic field H _R causes the magnetic bubbles to be transferred on the magnetic bubble expander S in the arrow p direction. During this transfer process, the magnetic bubble is expanded in the lateral direction, and is expanded (full stretch) until the width of the magnetic bubble expander S becomes wide. When the fully-stretched string-shaped bubble passes under the magnetic bubble detector line D, a large electric signal proportional to the length of the string-shaped bubble is obtained as a detection output.

FIG. 2 is an enlarged plan view showing an example of a conventional pattern of the above-mentioned magnetic bubble expander, in which FIG. 2 (a) has a symmetrical Sieplon pattern 1 as a basic element and is stacked in multiple layers to form an expander 1
An example of a symmetric Sieplon type magnetic bubble expander forming a step (column) S is shown, and FIG. 1 (b) shows an asymmetric Sieplon pattern 2 as a basic element. 2 is an example of an asymmetric Sieplon-shaped magnetic bubble expander forming a. It is formed with such a cieplon pattern as a basic element.

Further, as a basic element forming the magnetic bubble expander, a pattern as shown in the enlarged plan view of FIG. 3 has been conventionally used. That is, the magnetic domain width d of the expanding magnetic bubble is about 3
When it is as large as .mu.m or more, the pattern having the pattern period .lambda. of the basic element as shown in FIG. On the other hand, the magnetic domain width d is about 2μ
When miniaturized to m or less, a pattern having a pattern period λ of 3 to 4 times as long as 12d to 16d has been used as shown in FIG. When the magnetic domain width d of the magnetic bubbles is reduced in this way, mutual interference between the magnetic bubbles becomes stronger. Furthermore, recently, in order to increase the data reading speed to twice as fast as the conventional one, in the conventional case, one magnetic bubble detector line reads a magnetic bubble train transferred at two-hit intervals. A method of reading magnetic bubble trains that are continuously transferred has come to be used. In this case, mutual interference between magnetic bubbles becomes stronger. And
As the malfunction due to the mutual interference between the magnetic bubbles, the deterioration of the transfer characteristics of the magnetic bubbles and the detection output noise from the adjacent magnetic bubbles occur. In order to prevent malfunction due to mutual interference, the pattern period λ of the basic element is 3
Double-length to quadruple-length periodic patterns have been used. Further, in the case of this 3-fold to 4-fold long periodic pattern, a basic pattern having a plurality of bending points C in the middle portion of the pattern as shown in FIGS. 1'has been used.

However, the conventional magnetic bubble expander composed of such a 3-fold to 4-fold long period pattern has the problem as shown in FIG. In the figure, the horizontal axis represents the strength of the rotating magnetic field H _R and the vertical axis represents the strength of the bias magnetic field H _B , and the results are obtained by obtaining a region in which the magnetic bubble expander stably transfers the magnetic valve. That is, as shown in the figure, a transfer error occurs in the lower limit side of the bias magnetic field, that is, in the range of the region I,
There is a problem that a large margin loss occurs and the normal transfer area II on the upper limit side becomes narrow.

[Object of the Invention]

Therefore, the object of the present invention is to solve the above-mentioned problems of the conventional magnetic bubble expander, to prevent a transfer error on the lower limit side of the bias magnetic field H _B , and to detect output noise from an adjacent magnetic bubble. It is to provide a magnetic bubble expander with less power consumption.

[Outline of Invention]

According to the present invention, the period of the latter stage of the detector is set larger than that of the former stage (2
By doubling the above, it is possible to improve both the transfer characteristic and the noise resistance characteristic, which are in a dilemma, that is, if it is not established, it cannot be established.

According to the present invention, it is provided with a magnetic bubble detector and a magnetic bubble expander arranged before and after the magnetic bubble detector in the magnetic bubble transfer direction. There is provided a magnetic bubble expander in which the basic period of the magnetic bubble expander arranged immediately after the magnetic bubble detector is set to twice the basic cycle of the magnetic bubble expander arranged immediately before the magnetic bubble detector. It

Example of Invention

 Next, the present invention will be described in detail with reference to the drawings.

First, in order to examine the error mode generated in the transfer error region I of the magnetic bubble expander section described with reference to FIG. 4, a pattern as shown in FIG. 5 was prototyped and examined by experiment. In this case, the prototype pattern forms a part of the front side of the magnetic bubble detector line D with a quadruple length cycle pattern to form the magnetic bubble expander S _4, and the rear side of the magnetic bubble detector line D has a double length cycle pattern. To form a magnifier S ₂ . Then, as a result of investigating the portion where the transfer error occurs, it was found that the error occurred at the following location. That is, as shown in the figure, there are two locations, an outlet side portion of the magnetic bubble expander S ₄ consisting of a quadruple length period pattern and an outlet side portion of the magnetic bubble detector line D.
Further, in order to investigate the detection output noise from the adjacent bubble, which is the second problem described above, a pattern as shown in FIGS. 6 (a) and 6 (b) was prototyped and examined by an experiment. In the figure (a), one stage before the magnetic bubble detector line D forms a magnetic bubble detector S ₄ with a quadruple length cycle pattern, and the other part forms a magnetic bubble detector S ₂ with a double length cycle pattern. did. Then, as a result of examining the detection output noise from the adjacent magnetic bubbles,
In the case of FIG. 7A, a large amount of noise was output, whereas in the case of FIG. 3B, almost no noise was output. As a result, the noise from the adjacent magnetic bubble is dominated by the magnetic bubble immediately after the magnetic bubble detector line D. Therefore, by making the pattern of the magnetic bubble expander S immediately after that four times longer, This noise can be reduced.

The present invention will be described in detail below with reference to specific examples.

FIG. 7 is a diagram showing an example of a magnetic bubble expander according to the present invention, and the same symbols as those in the above-mentioned figures are the same elements, and therefore their explanations are omitted. In the figure, at least immediately after the magnetic bubble detector line D is characterized in that a magnetic bubble expander S ₄ consisting of a quadruple long period pattern is used. The magnetic bubble expander S ₄ subsequent to the magnetic bubble expander S ₄ uses the magnetic bubble expander S ₂ having a double-long period pattern. On the other hand, in front of the magnetic bubble detector line D, a magnetic bubble expander S ₂ having a double length period pattern is used.

With such a configuration, it is possible to solve the above-mentioned two problems of the related art. That is, first, the detection output noise from the adjacent magnetic bubbles can be greatly reduced as is clear from the experimental results described in FIG. Regarding the transfer characteristics of the magnetic bubble, there is no problem on the front side since the magnetic bubble expander S ₄ consisting of a quadruple long period pattern does not exist before the magnetic bubble detector line D. Further, the transfer error at the exit side B of the magnetic bubble detector line D described in FIG. 5 is caused by the magnetic bubble expander S ₄ consisting of a large quadruple long period pattern immediately after the magnetic bubble detector line D. By adopting this, the transfer force of the magnetic bubble becomes large and can be eliminated. Immediately after the magnetic bubble detector line D, a magnetic bubble expander S ₄ consisting of a quadruple long period pattern
The transfer error of the portion corresponding to the portion A described in FIG. 5 on the exit side of the above occurs in this embodiment. However, this error is an error after the magnetic bubble has passed through the magnetic bubble detector line D, and it is a magnetic bubble that is eventually swept to the outside of the guardrail after this, so even if an error occurs in this portion. It's an acceptable error with no real harm, and it's perfectly fine.

〔The invention's effect〕

As described above, according to the present invention, it is possible to obtain a magnetic bubble expander capable of suppressing magnetic bubble detector noise from adjacent magnetic bubbles and having no bias magnetic field margin loss due to transfer error. Have.

[Brief description of drawings]

FIG. 1 is a plan view of the essential parts showing the structure of the magnetic bubble expander, FIG. 2 is an enlarged plan view of the essential parts showing the basic element patterns forming the magnetic bubble expander, and FIG. 3 is a conventional pattern of the basic elements. FIG. 4 is an enlarged plan view of an essential part, FIG. 4 is a characteristic diagram showing problems of the conventional magnetic bubble expander, and FIGS. 5 and 6 are magnetic bubbles using an experimental pattern prototyped to investigate the conventional problems. FIG. 7 is a plan view of an essential part showing an expander, and FIG. 7 is a plan view of an essential part showing an example of the magnetic bubble expander according to the present invention. D ...... magnetic bubble detector line, S ...... magnetic bubble magnifier, S ₂ ...... ₂ Long period pattern magnetic bubble expansion instrument, S ₄ ...
… Magnifier with 4 times longer period pattern, 1,1 ′ ……
pattern.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mitsuru Sekino 3300 Hayano, Mobara-shi, Chiba Inside the Mobara factory, Hitachi, Ltd. (72) Inventor Naoki Miyamoto 3300 Hayano, Mobara-shi, Chiba Inside the Hitachi, Ltd. Mobara factory (72) 56) References JP-A-57-212683 (JP, A)

Claims (1)

[Claims] 1. A magnetic bubble detector comprising: a magnetic bubble detector; and a magnetic bubble expander arranged in front of and behind the magnetic bubble detector with respect to the magnetic bubble transfer direction. A magnetic bubble magnifier, wherein the basic period of the magnetic bubble expander arranged immediately after the bubble detector is set to twice the basic period of the magnetic bubble expander arranged immediately before the magnetic bubble detector. vessel.