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US 5,402,293 AGranted
Magneto-optical head having a thin film coil recessed into a magnetic substrate
AssigneeSony Electronics Inc.
InventorChristopher Smith
Life of this patent
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Abstract
A magneto-optical head formed of a magnetically permeable substrate in which an annular recess is formed in a planar surface of the substrate and a plurality of thin film windings are deposited in the recess to make up the coil windings of the head.
Claims14
A thin film magnetic head for magneto-optically recording data on a recording surface of a magneto-optic recording medium, comprising:
- a magnetic substrate having a planar surface arranged parallel to the recording surface of the magneto-optic recording medium, the planar surface having an annularly shaped recess therein which defines a center magnetic pole piece extending upward from the planar surface substantially perpendicular thereto and an annularly shaped, coaxial outer magnetic pole piece separated from the center magnetic pole piece by the annularly shaped recess;
- and
- a pair of separate thin film, continuous coils of conductive material positioned in the annularly shaped recess, each coil having a plurality of continuous windings positioned coaxially about the center magnetic pole piece, and with one of the coils overlaying the other coil and being separated from the other coil by an insulating material.
A method for forming a thin film magnetic head for magneto-optically recording data on a magneto-optic recording medium, comprising the steps of:
- providing a substrate of magnetic material having a planar surface;
- forming an annular groove in the planar surface of the substrate so as to define a central magnetic pole piece and an annular magnetic pole piece coaxial with the central magnetic pole piece on the planar surface, with the central magnetic pole piece and the annular magnetic pole piece extending perpendicular to surface of the substrate and separated from each other by the annular groove;
- and
- photolithographically forming on the planar surface in the groove a first coil of thin film conductive material around the central magnetic pole piece in a continuous spiral path, an insulating layer over the first coil, and a second coil of thin film conductive material around the central magnetic pole piece in a continuous spiral path, overlaying the first coil and being separate from it.
1 more element
Dependencies are inferred from the claim text.