US 4,291,346 A · Optoelectronic system for determining the position of a magnetic head transducer on a flexible magnetic recording disc

Abstract

An information storage system for recording data on a flexible magnetic recording disc is provided. The information storage system includes an optoelectronic system for determining the position of a magnetic head transducer, which is used to read and/or write information on the disc, with respect to the disc. The optoelectronic system has a moveable shutter member with a plurality of apertures formed therein for moving along with the head. The shutter member moves with respect to a stationary mask member having first and second sets of apertures formed therein. As the shutter moves, selected apertures of the mask member are in registration with apertures in the shutter, thereby allowing light to pass therethrough, while other apertures of the mask member are blocked off by solid portions of the shutter, thereby blocking off light passage. The optoelectronic system senses which apertures of the mask member are open and which are blocked off and generates an electrical signal indicative thereof. Since the shutter movements correspond to head movements, the signal corresponds to the relative position of the head with respect to the disc. The disc is comprised of a flexible plastic material which is subject to expansion and contraction due to environmental changes. To more accurately determine the position of the head, the shutter member is comprised of the same flexible plastic material as the disc. In another embodiment the mask member is also comprised of the same flexible plastic material as the disc.

Claims15

Dependent claims

A system for reading and/or writing information on a sheet of flexible information storage media, said system comprising:

(a) a cartridge contaning said sheet of information storage media, said cartridge having a first opening for providing access to said media to impart rotational motion thereto and a second opening for providing access to a recording surface of said media to read and/or write information thereon;
(b) rotational means for extending through said first opening to engage said media and impart rotational motion thereto;
(c) a magnetic head transducer disposed in registration with said second opening for reading and/or writing information on the recordng surface of said media;
and
(d) an optoelectronic system for optically determining the position of the head transducer with respect to the media in generating an electrical signal indicative thereof, said optoelectronic system having a movable shutter member with a plurality of apertures formed at predetermined intervals thereon for being moved relative to a stationary mask member, light energy being permitted to pass through selected portions of said mask member in dependence upon the position of said head transducer, said shutter member being comprised of substantially the same flexible material as said media and being formed by cutting said flexible material diagonally with respect to a first axis of the flexible material so that the differences in the thermal and hygroscopic expansion coefficients of the material along the first axis from the corresponding expansion coefficients along a second axis are compensated for and the average thermal and hygroscopic expansion coefficients of the shutter member are substantially the same as those of said media.

2 more elements

In an information storage system having a magnetic head transducer for reading and/or writing information on a sheet of flexible information storage media, an optoelectronic apparatus for determining the position of said head transducer, said optoelectronic apparatus comprising:

(a) a movable shutter member having a plurality of apertures formed at predetermined intervals thereon for being moved along the said head transducer, said shutter member being comprised of substantially the same flexible material as said media and being formed by cutting a piece of said flexible material diagonally with respect to a first axis of the flexible material so that differences in the thermal and hygroscopic expansion coefficients along the first axis from the corresponding coefficients along a second axis of the material are compensated for and the average thermal and hygroscopic expansion coefficients of the shutter member are substantially the same as those of said media, to compensate for environmental changes;
(b) a stationary mask member disposed in abutting relationship with said shutter member, said mask member having first and second sets of apertures formed at predetermined intervals thereon, selected ones of said apertures of said first and second sets of apertures being in registration with said apertures in said shutter member and allowing light energy to pass therethrough and others of said first and second sets of apertures being blocked off by solid portions of said shutter member to prevent light energy from passing therethrough in dependence upon the position of said shutter member relative to said mask member;
(c) light energy emitting means positioned adjacent to said shutter member for transmitting light energy in the direction of said shutter member and said mask member;
and
(d) light energy detector means positioned adjacent to said mask member on the opposite side thereof from said light emitting means for detecting light energy that passes through selected ones of said apertures in said mask member and generating an electrical signal corresponding thereto, said electrical signal being indicative of the position of said shutter member with respect to said mask member and the corresponding position of said head transducer with respect to said media.

2 more elements

Dependencies are inferred from the claim text.

Optoelectronic system for determining the position of a magnetic head transducer on a flexible magnetic recording disc

Life of this patent

Optoelectronic system for determining the position of a magnetic head transducer on a flexible magnetic recording disc

Life of this patent

Abstract

Claims15