Dynamic magnetic information storage or retrieval – Head – Core
Patent
1988-08-18
1990-07-17
Wolff, John H.
Dynamic magnetic information storage or retrieval
Head
Core
360119, G11B 512
Patent
active
049424904
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
The invention concerns a write/read head in thin layers and a method for manufacturing it which can be applied especially to magnetic heads.
DISCUSSION OF BACKGROUND
In the known technology for making magnetic heads in thin layers, the gap of the magnetic head is made by superimposing magnetic layers consituting the first magnetic pole, a non-magnetic layer consituting the gap itself and, finally, another succession of magnetic layers constituting the second pole.
For example, a magnetic head of this type is described in the French patent application No. 86 05238 filed on Apr. 11, 1986.
The unit is etched so as to define the height of the gap corresponding to the track width. After sawing, this gap is ground so as to adjust the depth of the gap.
The numerous types of thin layer heads differ in the nature of the substrates, superstrate and layers used as well as in the mode of manufacturing the coil. However, the mode of manufacturing the gap is always identical to the one mentioned above.
The operation for adjusting the depth of the gap is done individually and is very complex. For, this depth should not exceed about ten microns, otherwise there is the risk of excessively reducing the efficiency of the head. The sawing operation itself gives lack of precision of several tens of microns.
The known technology for thin layer magnetic heads thus comes up mainly against the difficulties entailed by a stage for the individual grinding of the heads, which is very costly and has a low success rate.
SUMMARY OF THE INVENTION
The invention therefore provides for integrating this grinding stage in the operations prior to the sawing of the substrate, thus reducing its cost by a ratio close to the level of integration of the heads on the substrate, which may reach a rate of 1000. Furthermore, according to the invention, the type of head made is more efficient than prior art heads.
The invention therefore concerns a magnetic write/read head in thin layers characterized in that it comprises: flank forming an angle with the main side; non/magnetic material located between the second pole and the main side, this second pole also having a second flank which is substantially perpendicular to the main side and defines a gap of substantially constant thickness with the first flank.
The invention also concerns a method for making a magnetic head in thin layers comprising the following successive steps: substrate, of a first magnetic pole having a flank that forms an angle with the side of the substrate; the first magnetic pole, of a layer of a non-magnetic material; non-magnetic material, of a second magnetic pole, one part of which overlaps the flank of the first pole; non-magnetic material and of the second magnetic pole.
BRIEF DESCRIPTION OF THE DRAWINGS
The various objects and features of the invention will appear more clearly from the following description, made with reference to appended fiqures, of which: in thin layers according to the invention; induction circuits; the invention; to the invention; invention wherein magnetic field induction coils are deposited on the same side of the substrate as the magnetic poles of the head; according to the invention; according to the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to a FIG. 1, we shall first describe an embodiment of a magnetic head according to the invention. This head has a substrate part or supporting part 1 with a plane side 10.
This plane side 10 has a first magnetic head pole 2 which has a flank 20 forming an angle with the plane of the side 10. According to the embodiment shown in FIG. 1, the flank 20 is substantially perpendicular to the plane of the side 10. The side 10 also bears a layer 4 of a non-magnetic material which covers the flank 20 of the first pole 2. The layer 4 has a second pole 3, a flank 30 of which is substantially perpendicular to the plane of the side 10 and parallel to the flank 20.
The flanks 20 and 30 define a gap 5 between the poles 2 and 3.
The upper sid
REFERENCES:
patent: 4399479 (1983-08-01), Meckel
"Thomson-CSF"
Wolff John H.
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