Conductive video disc

Claim 2

A video information record, adapted for use with a playback stylus to effect recovery of signals occupying a bandwidth of at least several megaherz when relative motion at a desired rate is established between said record and said stylus, said record comprising a disc of a moldable plastic material containing a sufficient amount of finely divided conductive particles so that the material has a bulk resistivity below about 500 ohm-centimeters at 900 MHz and having a layer of dielectric material at the disc surface, said surface having a spiral groove therein, said groove dimensioned for reception therein of said playback stylus and containing an information track constituted by a surface relief pattern in said groove of such dimension to accommodate recovery of signals of said bandwidth upon establishment of said motion at said rate.

Claim 3

An information record according to claim 1 wherein said conductive particles are carbon black.

Claim 4

An information record according to claim 1 wherein the bulk resistivity is below about 100 ohm-centimeters.

Claim 5

An information record according to claim 2 wherein said carbon black has an apparent bulk density of about 150 grams per liter.

Claim 6

An information record according to claim 1 which has a spiral groove containing an information track on both major surfaces.

Claim 7

An information record according to claim 1 wherein said plastic is a polymer of vinyl chloride.

Claim 8

A video information record, adapted for use with a playback stylus to effect recovery of signals occupying a bandwidth of at least several megahertz when relative motion at a desired rate is established between said record and said stylus, said record comprising a disc of a moldable plastic material containing a sufficient amount of finely divided conductive particles so that the material has a bulk resistivity below about 500 ohm-centimeters at 900 MHz and having a layer of dielectric material at the disc surface and containing an information track constituted by a surface relief pattern of such dimension to accommodate recovery of signals of said bandwidth upon establishment of said motion at said rate.

Claim 9

A video information record, adapted for use with a playback stylus to effect recovery of signals occupying a bandwidth of at least several megahertz when relative motion at a desired rate is established between said record and said stylus, said record comprising a disc of a moldable plastic material containing a sufficient amount of finely divided conductive particles so that the material has a bulk resistivity below about 500 ohm-centimeters at 900 MHz and having a layer of dielectric material at the disc surface and containing an information track constituted by a surface relief pattern of such dimension to accommodate recovery of signals of said bandwidth upon establishment of said motion at said rate.

Claim 10

An information record according to claim 7 wherein said conductive particles are carbon black.

Claim 11

An information record according to claim 8 wherein said carbon black has an apparent bulk density of about 150 grams per liter.

Claim 12

An information record according to claim 7 wherein the bulk resistivity is below about 100 ohm-centimeters.

Claim 13

An information record according to claim 10 wherein said conductive particles are carbon black having an apparent bulk density of about 150 grams per liter.

Claim 14

In a recording means comprising a conductive disc having a layer of dielectric material at the disc surface and an information track containing video information in the form of a surface relief pattern and a uniform conformal lubricant layer disposed on the surface of said disc, the improvement which comprises employing as the disc material a plastic molding composition containing from about 10 to about 20 parts by weight of finely divided conductive carbon particles having an apparent bulk density of about 150 grams per liter per 100 parts by weight of the molding composition.

Claim 15

In a recording means comprising a conductive disc having a layer of dielectric material at the disc surface and an information track containing video information in the form of a surface relief pattern and a uniform conformal lubricant layer disposed on the surface of said disc, the improvement which comprises employing as the disc material a plastic molding composition containing from about 10 to about 20 parts by weight of finely divided conductive carbon particles having an apparent bulk density of about 150 grams per liter per 100 parts by weight of the molding composition.

Claim 16

A recording means according to claim 12 wherein about 15 parts by weight of carbon black per 100 parts by weight of the molding composition is present.

Claim 17

A recording means according to claim 12 wherein the plastic is a polymer of vinyl chloride.

Claim 18

A recording means according to claim 12 wherein said information track is in the form of a spiral groove adapted to receive a playback stylus.

Claim 19

A recording means according to claim 12 wherein said lubricant is a methyl alkyl siloxane of the formula ##STR6## wherein R is an alkyl group of 4-20 carbon atoms and x is an integer.

Claim 20

In a capacitive recording means comprising a conductive disc of a moldable plastic having a layer of a dielectric material at the disc surface and containing an information track containing video information in the form of a surface relief pattern, the improvement which comprises employing as the moldable plastic a polymer of vinyl chloride containing from about 10 to about 20 parts by weight of conductive carbon particles having a particle size below about 500 angstroms and an apparent bulk density of about 150 grams per liter, per 100 parts by weight of the molding composition.

Claim 21

In a capacitive recording means comprising a conductive disc of a moldable plastic having a layer of a dielectric material at the disc surface and containing an information track containing video information in the form of a surface relief pattern, the improvement which comprises employing as the moldable plastic a polymer of vinyl chloride containing from about 10 to about 20 parts by weight of conductive carbon particles having a particle size below about 500 angstroms and an apparent bulk density of about 150 grams per liter, per 100 parts by weight of the molding composition.

Claim 22

A recording means according to claim 17 wherein about 15 parts by weight of carbon black is present per 100 parts by weight of the molding composition.

Claim 23

A recording means according to claim 17 wherein said information track is in the form of a spiral groove adapted to receive a playback stylus.

Claim 24

A video information record, adapted for use with a playback stylus to effect recovery of signals occupying a bandwidth of at least several megahertz when relative motion at a desired rate is established between said record and said stylus, said record comprising a disc of a moldable plastic material containing a sufficient amount of finely divided conductive particles so that video signals can be reconstituted on playback with said stylus and having a layer of dielectric material at the disc surface, said surface containing an information track constituted by a surface relief pattern of such dimension to accommodate recovery of signals of said bandwidth upon establishment of said motion at said rate.

Claim 25

A video information record, adapted for use with a playback stylus to effect recovery of signals occupying a bandwidth of at least several megahertz when relative motion at a desired rate is established between said record and said stylus, said record comprising a disc of a moldable plastic material containing a sufficient amount of finely divided conductive particles so that video signals can be reconstituted on playback with said stylus and having a layer of dielectric material at the disc surface, said surface containing an information track constituted by a surface relief pattern of such dimension to accommodate recovery of signals of said bandwidth upon establishment of said motion at said rate.

Claim 26

An information record according to claim 20 wherein said conductive particles are carbon black.

Claim 27

An information record according to claim 21 wherein the carbon black particles have a particle size of less than about 500 angstroms.

Claim 28

An information record according to claim 21 wherein said carbon black has an apparent bulk density of about 150 grams per liter.

Claim 29

An information record according to claim 23 wherein said moldable plastic material contains up to about 20 parts by weight of said carbon black for 100 parts of the moldable material.

Claim 30

An information record according to claim 21 containing up to 35 percent by weight of carbon black by weight of the molding composition.

Claim 31

An information record according to claim 20 which has a spiral groove containing an information track on both major surfaces.

Claim 32

An information record according to claim 20 wherein said plastic is a polymer of vinyl chloride.

Claim 33

In a recording medium of electrostatic capacitance type on which an information signal has been recorded as variation of geometrical shape of the recording surface part of the recording medium, and from which the signal is reproduced by the variation, in response to said variation of geometrical shape, of the electrostatic capacitance between an electrode of a reproducing stylus tracing relatively the recording surface of the medium and said recording surface part, the improvement comprising; that at least said surface part of the recording medium has the geometric shape variation molded from a thermoplastic synthetic resin into which an electroconductive material in powder or particle form has been admixed; and said synthetic resin forming an outer surface cover of said surface part of the medium, to thereby prevent exposure of said electroconductive material to the outside.

Claim 34

In a recording medium of electrostatic capacitance type on which an information signal has been recorded as variation of geometrical shape of the recording surface part of the recording medium, and from which the signal is reproduced by the variation, in response to said variation of geometrical shape, of the electrostatic capacitance between an electrode of a reproducing stylus tracing relatively the recording surface of the medium and said recording surface part, the improvement comprising; that at least said surface part of the recording medium has the geometric shape variation molded from a thermoplastic synthetic resin into which an electroconductive material in powder or particle form has been admixed; and said synthetic resin forming an outer surface cover of said surface part of the medium, to thereby prevent exposure of said electroconductive material to the outside.