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Readback Head for High Density Recording

IP.com Disclosure Number: IPCOM000094186D
Original Publication Date: 1966-Jul-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 22K

Publishing Venue

IBM

Related People

Morrison, JR: AUTHOR [+3]

Abstract

A thin-film head is provided for detecting information recorded at high densities. This head overcomes the problems of other thin-film heads by providing well-defined detectable signals. Adequate switching of the film also occurs to permit magneto-optic readout.

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Readback Head for High Density Recording

A thin-film head is provided for detecting information recorded at high densities. This head overcomes the problems of other thin-film heads by providing well-defined detectable signals. Adequate switching of the film also occurs to permit magneto-optic readout.

To form the thin-film head, layer 1 of a soft magnetic material, such as permalloy, is deposited on glass substrate 2. Nonmagnetic material 3 is then deposited on layer 1 to form the transducing gap of the head. Material 3 has a thickness approximating 10 microinches and a depth of less than.01 inch. Then another layer of soft magnetic material 4 is deposited over material 3 and layer 2.

In operation, detection of a bit of information causes the flux in layers 1 and 4 to switch in the direction of the arrow around gap 3. This causes switching of the entire magnetic material surface, including region 5. If the next bit of detected information is of the opposite type, the flux path around gap 3 is in the opposite direction. If the next detected bit is the same type, there is no change in the path of the flux around gap 3.

To complete the readout, a coil can be wrapped around the film to carry a signal generated by the flux changes in the film. Alternately, magneto-optic readout is accomplished by directing a finely-defined light beam at region 5 of the head. Observation is then made of the reflected light patterns to determine the detected information.

To further inc...