Rotary disc recording and readout system having capacitance controlled lens positioning means

Claim 2

In combination with a recording and reproducing system of the type having an adjustable lens assembly for focusing an energy beam on the surface of a record having a nonconductive recording film supported on a conductive substrate, a ring-shaped electrode physically connected to the lens assembly and concentrically arranged with respect to the beam, the electrode projecting from the lens assembly toward the film and being positioned in noncontacting proximity to the surface of the film, and means for adjusting the position of the lens assembly in response to the capacitance between the electrode and the conductive substrate so that the focal plane of the lens coincides with the surface of the film at all times, the improvement wherein: 1. a record and rotary turntable assembly is provided, the record being a circular disc having a conductive outer surface and the recording film comprising a thermoplastic film permanently deposited on the conductive surface of the record, the record being mounted for rotation with the turntable when information is to be recorded or read out from the record; 2. means are provided for mounting the lens assembly with respect to the turntable, said mounting means including a recording arm movable with respect to the turntable to position the lens assembly opposite to any selected one of a plurality of generally circular recording channels formed in the recording surface of the record; and 3. the electrode comprises a flat disc mounted parallel to the record on the turntable, the electrode having a circular central hole aligned concentrically with respect to the beam and having an elliptical perimeter, the major axis of the ellipse being positioned tangent to the selected recording channel.

Claim 3

means are provided for mounting the lens assembly with respect to the turntable, said mounting means including a recording arm movable with respect to the turntable to position the lens assembly opposite to any selected one of a plurality of generally circular recording channels formed in the recording surface of the record; and

Claim 4

means are provided for mounting the lens assembly with respect to the turntable, said mounting means including a recording arm movable with respect to the turntable to position the lens assembly opposite to any selected one of a plurality of generally circular recording channels formed in the recording surface of the record; and

Claim 5

In combination with a recording and reproducing system of the type having an adjustable lens assembly for focusing an energy beam on the surface of a record having a nonconductive recording film supported on a conductive substrate, an electrode physically connected to the lens assembly and projecting from the lens assembly toward the film, and means for adjusting the position of the lens assembly in response to the capacitance between the electrode and the conductive substrate so that the focal plane of the lens coincides with the surface of the film at all times, the improvement wherein: a record and rotary turntable assembly is provided, the record comprising a circular disc having a flat glass substrate, a conductive metal film deposited on the outer surface of the glass substrate and selected from the group consisting of copper, silver, and aluminum, and the recording film comprising a thermoplastic permanently deposited on the conductive film on the record, the record being mounted for rotation with the turntable when information is to be recorded or read out from the record; means are provided for mounting the lens assembly with respect to the turntable, said mounting means including an arm movable with respect to the turntable to position the lens Assembly opposite to any selected one of a plurality of generally circular recording channels formed in the recording surface of the record; and the electrode comprises a flat disc mounted parallel to the record on the turntable, the electrode having a circular central hole aligned concentrically with respect to the beam and having an elliptical perimeter, the major axis of the ellipse being positioned tangent to the selected recording channel.

Claim 6

In combination with a recording and reproducing system of the type having an adjustable lens assembly for focusing an energy beam on the surface of a record having a nonconductive recording film supported on a conductive substrate, an electrode physically connected to the lens assembly and projecting from the lens assembly toward the film, and means for adjusting the position of the lens assembly in response to the capacitance between the electrode and the conductive substrate so that the focal plane of the lens coincides with the surface of the film at all times, the improvement wherein: a record and rotary turntable assembly is provided, the record comprising a circular disc having a flat glass substrate, a conductive metal film deposited on the outer surface of the glass substrate and selected from the group consisting of copper, silver, and aluminum, and the recording film comprising a thermoplastic permanently deposited on the conductive film on the record, the record being mounted for rotation with the turntable when information is to be recorded or read out from the record; means are provided for mounting the lens assembly with respect to the turntable, said mounting means including an arm movable with respect to the turntable to position the lens Assembly opposite to any selected one of a plurality of generally circular recording channels formed in the recording surface of the record; and the electrode comprises a flat disc mounted parallel to the record on the turntable, the electrode having a circular central hole aligned concentrically with respect to the beam and having an elliptical perimeter, the major axis of the ellipse being positioned tangent to the selected recording channel.

Claim 7

In combination with a recording and reproducing system of the type having an adjustable lens assembly for focusing an energy beam on the surface of a record having a nonconductive recording film supported on a conductive substrate, an electrode physically connected to the lens assembly and projecting from the lens assembly toward the film, and means for adjusting the position of the lens assembly in response to the capacitance between the electrode and the conductive substrate so that the focal plane of the lens coincides with the surface of the film at all times, the improvement wherein: a record and rotary turntable assembly is provided, the record comprising a circular disc having a flat glass substrate, a conductive metal film deposited on the outer surface of the glass substrate and selected from the group consisting of copper, silver, and aluminum, and the recording film comprising a thermoplastic film permanently deposited on the conductive film on the record, the record being mounted for rotation with the turntable when information is to be recorded or read out from the record; the record further comprises a conductive metal hub, on which the glass disc is cemented and which is arranged for mounting concentrically on the turntable; the conductive metal film extends inwardly past the glass substrate into electrical contact with the hub; the turntable is made of conductive metal and is grounded; and the means for adjusting the position of the lens assembly includes means for applying a potential to the electrode to generate a measurable capacitance between the electrode and the grounded conductive film underlying the recording film.

Claim 8

In combination with a recording and reproducing system of the type having an adjustable lens assembly for focusing an energy beam on the surface of a record having a nonconductive recording film supported on a conductive substrate, an electrode physically connected to the lens assembly and projecting from the lens assembly toward the film, and means for adjusting the position of the lens assembly in response to the capacitance between the electrode and the conductive substrate so that the focal plane of the lens coincides with the surface of the film at all times, the improvement wherein: a record and rotary turntable assembly is provided, the record comprising a circular disc having a flat glass substrate, a conductive metal film deposited on the outer surface of the glass substrate and selected from the group consisting of copper, silver, and aluminum, and the recording film comprising a thermoplastic film permanently deposited on the conductive film on the record, the record being mounted for rotation with the turntable when information is to be recorded or read out from the record; the record further comprises a conductive metal hub, on which the glass disc is cemented and which is arranged for mounting concentrically on the turntable; the conductive metal film extends inwardly past the glass substrate into electrical contact with the hub; the turntable is made of conductive metal and is grounded; and the means for adjusting the position of the lens assembly includes means for applying a potential to the electrode to generate a measurable capacitance between the electrode and the grounded conductive film underlying the recording film.

Claim 9

the electrode comprises a flat disc mounted parallel to the record on the turntable, the electrode having a circular central hole aligned concentrically with respect to the beam and having an elliptical perimeter, the major axis of the ellipse being positioned tangent to the selected recording channel.

Claim 10

the electrode comprises a flat disc mounted parallel to the record on the turntable, the electrode having a circular central hole aligned concentrically with respect to the beam and having an elliptical perimeter, the major axis of the ellipse being positioned tangent to the selected recording channel.

Claim 11

In combination with a system of recording information in a recording surface of a moving thermoplastic film, and reading out recorded information, of the type wherein the recording surface is exposed to a focused beam of actinic radiation from a focusing lens assembly positioned in spaced relationship to the surface of the film, an improved automatically focusing recording and reproducing apparatus, which comprises: a record assembly having a central hub of electrically conductive material, a record substrate consisting of an annular circular disc secured to the hub and projecting outwardly therefrom, the substrate having a flat electrically conductive outer surface extending into electrical contact with the hub, the thermoplastic recording film being deposited on the conductive surface as a flat film defining an annular recording surface; a grounded rotary turntable of electrically conductive material having a horizontal platform and a shaft extending vertically downward from the platform, for rotating the turntable; electrically conductive means for detachably mounting the record hub on the turntable for rotation therewith when it is desired to record or reproduce from a particular record assembly, the mounting means being arranged so that the recording surface is located in a predetermined horizontal plane around the turntable, and so that the conductive surface of the substrate underlying the recording film is electrically connected to ground through the hub and the turntable; a pivoted recording arm mounted in spaced relationship to the turntable and to the recording surface of the record when placed on the turntable; a lens assembly mounted on the recording arm and including an outer holder fixed to the record arm, and a focusing lens housing for projecting a focused beam toward the recording surface, the lens housing beiNg reciprocably mounted within the lens holder for vertical movement toward and away from the recording surface of the thermoplastic film so as to permit adjustment of the focus of the beam with respect to the recording surface; means for pivoting the recording arm with respect to the record so as to select a particular generally circular track on the surface of the record for recording or reading out with the focused beam; an electrode physically connected to the lens unit for vertical movement therewith and spaced from the recording surface of the thermoplastic film, the electrode being electrically insulated from the lens unit; means for continuously applying an electrical signal to the electrode so as to establish instantaneous values of capacitance between the electrode and the grounded conductive surface of the substrate, indicating the position of the lens unit with respect to the recording surface and thus the focus distance of the beam; capacitance monitoring means for sensing the capacitance to ground between the electrode and the conductive surface and for comparing the instantaneous values of sensed capacitance with a reference capacitance based on the desired focus distance so as to generate a difference signal based on deviations from the reference capacitance; and a servomechanism responsive to the capacitance monitoring means for vertically positioning the lens unit in the holder so as to adjust the focus distance to the desired length.

Claim 12

In combination with a system of recording information in a recording surface of a moving thermoplastic film, and reading out recorded information, of the type wherein the recording surface is exposed to a focused beam of actinic radiation from a focusing lens assembly positioned in spaced relationship to the surface of the film, an improved automatically focusing recording and reproducing apparatus, which comprises: a record assembly having a central hub of electrically conductive material, a record substrate consisting of an annular circular disc secured to the hub and projecting outwardly therefrom, the substrate having a flat electrically conductive outer surface extending into electrical contact with the hub, the thermoplastic recording film being deposited on the conductive surface as a flat film defining an annular recording surface; a grounded rotary turntable of electrically conductive material having a horizontal platform and a shaft extending vertically downward from the platform, for rotating the turntable; electrically conductive means for detachably mounting the record hub on the turntable for rotation therewith when it is desired to record or reproduce from a particular record assembly, the mounting means being arranged so that the recording surface is located in a predetermined horizontal plane around the turntable, and so that the conductive surface of the substrate underlying the recording film is electrically connected to ground through the hub and the turntable; a pivoted recording arm mounted in spaced relationship to the turntable and to the recording surface of the record when placed on the turntable; a lens assembly mounted on the recording arm and including an outer holder fixed to the record arm, and a focusing lens housing for projecting a focused beam toward the recording surface, the lens housing beiNg reciprocably mounted within the lens holder for vertical movement toward and away from the recording surface of the thermoplastic film so as to permit adjustment of the focus of the beam with respect to the recording surface; means for pivoting the recording arm with respect to the record so as to select a particular generally circular track on the surface of the record for recording or reading out with the focused beam; an electrode physically connected to the lens unit for vertical movement therewith and spaced from the recording surface of the thermoplastic film, the electrode being electrically insulated from the lens unit; means for continuously applying an electrical signal to the electrode so as to establish instantaneous values of capacitance between the electrode and the grounded conductive surface of the substrate, indicating the position of the lens unit with respect to the recording surface and thus the focus distance of the beam; capacitance monitoring means for sensing the capacitance to ground between the electrode and the conductive surface and for comparing the instantaneous values of sensed capacitance with a reference capacitance based on the desired focus distance so as to generate a difference signal based on deviations from the reference capacitance; and a servomechanism responsive to the capacitance monitoring means for vertically positioning the lens unit in the holder so as to adjust the focus distance to the desired length.