High-density capacitive information records and playback apparatus therefor

Claim 2

A high-density information record playback system comprising: a disc record having a constant-width spiral groove in a surface thereof, the center-to-center spacing of successive convolutions thereof being substantially constant and independent of recorded information; said groove containing an information track constituted by variations in the geometry of the bottom of the groove representative of recorded information, and having sidewalls of a configuration which is substantially constant throughout said successive convolutions and independent of the groove bottom geometry variations representative of recorded information; a stylus having a tip subject to reception in said disc groove during playback use; said stylus including a support of insulating material, and an electrode of conductive material secured to said insulating support, said electrode presenting a surface of the disc groove bottom when said tip is received in said disc groove, which surface has a greater dimension in a lateral direction extending between said groove sidewalls and a lesser dimension in a longitudinal direction along said groove and normal to said lateral direction; a turntable for supporting said disc in a playing position permitting said disc groove reception of said stylus tip; means for rotating said turntable to establish relative motion between said disc groove and said stylus tip; and means electrically connected to said stylus electrode for developing an electrical signal representative of groove bottom geometry variations passing beneath said stylus electrode surface when said relative motion occurs.

Claim 3

A video signal record playback system comprising: a disc record having a constant-width spiral groove in the surface thereof, the center-to-center spacing of successive convolutions thereof being substantially constant and independent of recorded information; said groove containing an information track constituted by variations in the geometry of the bottom of the groove representative of video signal information, and having sidewalls of a configuration which is substantially constant throughout said successive conVolutions and independent of the groove bottom geometry variations representative of recorded video signal information; a stylus having a tip subject to reception in said disc groove during playback use; said stylus including a support of insulating material, and an electrode of conductive material secured to said insulating support, said electrode presenting a surface to the disc groove bottom when said tip is received in said disc groove, which surface has a greater dimension in a lateral direction extending between said groove sidewalls and a lesser dimension in a longitudinal direction along said groove and normal to said lateral direction; a turntable for supporting said disc in a playing position permitting said disc groove reception of said stylus tip; means for rotating said turntable to establish relative motion between said disc groove and said stylus tip; and means electrically connected to said stylus electrode for developing an electrical signal representative of groove bottom geometry variations passing beneath said stylus electrode surface when said relative motion occurs.

Claim 4

A video signal record playback system comprising: a disc record having a constant-width spiral groove in the surface thereof, the center-to-center spacing of successive convolutions thereof being substantially constant and independent of recorded information; said groove containing an information track constituted by variations in the geometry of the bottom of the groove representative of video signal information, and having sidewalls of a configuration which is substantially constant throughout said successive conVolutions and independent of the groove bottom geometry variations representative of recorded video signal information; a stylus having a tip subject to reception in said disc groove during playback use; said stylus including a support of insulating material, and an electrode of conductive material secured to said insulating support, said electrode presenting a surface to the disc groove bottom when said tip is received in said disc groove, which surface has a greater dimension in a lateral direction extending between said groove sidewalls and a lesser dimension in a longitudinal direction along said groove and normal to said lateral direction; a turntable for supporting said disc in a playing position permitting said disc groove reception of said stylus tip; means for rotating said turntable to establish relative motion between said disc groove and said stylus tip; and means electrically connected to said stylus electrode for developing an electrical signal representative of groove bottom geometry variations passing beneath said stylus electrode surface when said relative motion occurs.

Claim 5

A grooved high-density information record playback system comprising: a disc record having a spiral groove in a surface thereof of a substantially constant width independent of recorded information, the center-to-center spacing of successive convolutions thereof being substantially constant and independent of recorded information; said groove containing an information track constituted by variations in the geometry of the bottom of the groove representative of recorded information, and having sidewalls of a configuration which is substantially constant throughout said successive convolutions and independent of the groove bottom geometry variations representative of recorded information; a stylus having a tip subject to reception in said disc groove during playback use; said stylus including a support of insulating material, and an electrode of conductive material secured to said insulating support, said electrode presenting a surface to the disc groove bottom when said tip is received in said disc groove, which surface has a greater dimension in a lateral direction extending between said groove sidewalls and a lesser dimension in a longitudinal direction along said groove and normal to said lateral direction; the substantially constant configuration of said groove sidewalls limiting the depth of stylus tip entry in said groove to a dimension which is substantially constant throughout said successive convolutions and independent of the contents of said information track; a turntable for supporting said disc in a playing position permitting said disc groove reception of said stylus tip; means for rotating said turntable to establish relative motion between said disc groove and said stylus tip; and means electrically connected to said stylus electrode for developing an electrical signal representative of groove bottom depth variations passing beneath said stylus electrode surface when said relative motion occurs.

Claim 6

A grooved high-density information record playback system comprising: a disc record having a spiral groove in a surface thereof of a substantially constant width independent of recorded information, the center-to-center spacing of successive convolutions thereof being substantially constant and independent of recorded information; said groove containing an information track constituted by variations in the geometry of the bottom of the groove representative of recorded information, and having sidewalls of a configuration which is substantially constant throughout said successive convolutions and independent of the groove bottom geometry variations representative of recorded information; a stylus having a tip subject to reception in said disc groove during playback use; said stylus including a support of insulating material, and an electrode of conductive material secured to said insulating support, said electrode presenting a surface to the disc groove bottom when said tip is received in said disc groove, which surface has a greater dimension in a lateral direction extending between said groove sidewalls and a lesser dimension in a longitudinal direction along said groove and normal to said lateral direction; the substantially constant configuration of said groove sidewalls limiting the depth of stylus tip entry in said groove to a dimension which is substantially constant throughout said successive convolutions and independent of the contents of said information track; a turntable for supporting said disc in a playing position permitting said disc groove reception of said stylus tip; means for rotating said turntable to establish relative motion between said disc groove and said stylus tip; and means electrically connected to said stylus electrode for developing an electrical signal representative of groove bottom depth variations passing beneath said stylus electrode surface when said relative motion occurs.

Claim 7

A stylus, for use in playback of a grooved disc recording, said stylus comprising: a support of insulating material providing the tip of said stylus with insulating sidewalls dimensioned for disc groove sidewall engagement; and a conductive electrode, affixed to said insulating support in a location substantially centered with respect to said insulating sidewalls, and having a surface exposed at the bottom of said stylus tip, said conductive electrode having a lateral dimension, in a direction extending between said insulating sidewalls, which is foreshortened relative to the distance between said insulating sidewalls to a degree precluding disc groove sidewall engagement by said conductive electrode.

Claim 8

A stylus, for use in playback of a grooved disc recording, said stylus comprising: a support of insulating material providing the tip of said stylus with insulating sidewalls dimensioned for disc groove sidewall engagement; and a conductive electrode, affixed to said insulating support in a location substantially centered with respect to said insulating sidewalls, and having a surface exposed at the bottom of said stylus tip, said conductive electrode having a lateral dimension, in a direction extending between said insulating sidewalls, which is foreshortened relative to the distance between said insulating sidewalls to a degree precluding disc groove sidewall engagement by said conductive electrode.

Claim 9

A stylus, for use in playback of a grooved disc recording, said stylus comprising: a stylus tip having insulating sidewalls for disc groove sidewall engagement, said insulating sidewalls beinG constituted by opposite edges of a support element of insulating material; and a conductive electrode, embedded within said insulating support element, and having a surface exposed at the bottom of said stylus tip, said conductive electrode having a lateral dimension, in a direction extending between said insulating sidewalls, which is foreshortened relative to the distance between said insulating sidewalls whereby disc groove sidewall engagement of said conductive electrode is precluded.

Claim 10

A stylus, for use in playback of a grooved disc recording, said stylus comprising: a stylus tip having insulating sidewalls for disc groove sidewall engagement, said insulating sidewalls beinG constituted by opposite edges of a support element of insulating material; and a conductive electrode, embedded within said insulating support element, and having a surface exposed at the bottom of said stylus tip, said conductive electrode having a lateral dimension, in a direction extending between said insulating sidewalls, which is foreshortened relative to the distance between said insulating sidewalls whereby disc groove sidewall engagement of said conductive electrode is precluded.

Claim 11

A stylus, for use in playback of a grooved disc recording, said stylus comprising: a stylus tip having insulating sidewalls for disc groove sidewall engagement, said insulating sidewalls being constituted by opposite edges of a support element of insulating material; and a conductive electrode, affixed to said insulating support element, said conductive electrode having a lateral dimension, in a direction extending between said insulating sidewalls, which is foreshortened relative to the distance between said insulating sidewalls whereby disc groove sidewall engagement by said conductive electrode is precluded, said conductive electrode terminating in a surface at the bottom of said stylus tip having a greater dimension in said lateral direction extending between said stylus sidewalls and a lesser dimension in a direction transverse to said lateral direction.

Claim 12

A stylus, for use in playback of a grooved disc recording, said stylus comprising: a stylus tip having insulating sidewalls for disc groove sidewall engagement, said insulating sidewalls being constituted by opposite edges of a support element of insulating material; and a conductive electrode, affixed to said insulating support element, said conductive electrode having a lateral dimension, in a direction extending between said insulating sidewalls, which is foreshortened relative to the distance between said insulating sidewalls whereby disc groove sidewall engagement by said conductive electrode is precluded, said conductive electrode terminating in a surface at the bottom of said stylus tip having a greater dimension in said lateral direction extending between said stylus sidewalls and a lesser dimension in a direction transverse to said lateral direction.

Claim 13

A stylus, for use in playback of a grooved disc recording, said stylus comprising: a support of insulating material providing the tip of said stylus with insulating sidewalls, the spacing therebetween being such as to permit disc groove sidewall engagement of said insulating sidewalls in said playback use; and a conductive electrode, secured to said insulating support in a location substantially centered with respect to said insulating sidewalls, and having a surface exposed at the bottom of said stylus tip, said conductive electrode having a lateral dimension, in a direction extending between said insulating sidewalls, which is foreshortened relative to the distance between said insulating sidewalls whereby disc groove sidewall engagement by said conductive electrode is precluded, said electrode terminating at the bottom of said stylus tip in said exposed surface which has a greater dimension in said lateral direction extending between said stylus sidewalls and a lesser dimension in a direction transverse to said lateral direction.

Claim 14

A stylus, for use in playback of a grooved disc recording, said stylus comprising: a support of insulating material providing the tip of said stylus with insulating sidewalls, the spacing therebetween being such as to permit disc groove sidewall engagement of said insulating sidewalls in said playback use; and a conductive electrode, secured to said insulating support in a location substantially centered with respect to said insulating sidewalls, and having a surface exposed at the bottom of said stylus tip, said conductive electrode having a lateral dimension, in a direction extending between said insulating sidewalls, which is foreshortened relative to the distance between said insulating sidewalls whereby disc groove sidewall engagement by said conductive electrode is precluded, said electrode terminating at the bottom of said stylus tip in said exposed surface which has a greater dimension in said lateral direction extending between said stylus sidewalls and a lesser dimension in a direction transverse to said lateral direction.

Claim 15

In combination: a high-density information record disc of thermoplastic material; said disc having a constant-width spiral groove in a surface thereof, the center-to-center spacing of successive convolutions thereof being substantially constant and independent of recorded information; said groove containing an information track constituted by variations in the geometry of the bottom of the groove representative of recorded information, and having sidewalls of a configuration which is substantially constant throughout said successive convolutions and independent of the groove bottom geometry variation representative of recorded information; a stylus having a tip subject to reception in said disc groove; said stylus including a support of insulating material providing the tip of said stylus with insulating sidewalls for disc groove sidewall engagement when said tip is received in said disc groove, and a conductive electrode, affixed to said insulating support in a location substantially centered with respect to said insulating sidewalls, and presenting a surface to the bottom of said stylus tip, said conductive electrode having a lateral dimension in a direction extending between said insulating sidewalls, which is sufficiently foreshortened relative to the distance between said insulating sidewalls to preclude disc groove sidewall engagement by said conductive electrode when said stylus tip is received in said disc groove; means for establishing relative motion between said disc groove and said stylus tip under conditions of reception of said stylus tip within said disc groove; conductive means in proximity to said information track; and means responsive to capacitance variations exhibited between said stylus electrode and said conductive means during said motion for providing an electrical signal representative of said recorded information.

Claim 16

In combination: a high-density information record disc of thermoplastic material; said disc having a constant-width spiral groove in a surface thereof, the center-to-center spacing of successive convolutions thereof being substantially constant and independent of recorded information; said groove containing an information track constituted by variations in the geometry of the bottom of the groove representative of recorded information, and having sidewalls of a configuration which is substantially constant throughout said successive convolutions and independent of the groove bottom geometry variation representative of recorded information; a stylus having a tip subject to reception in said disc groove; said stylus including a support of insulating material providing the tip of said stylus with insulating sidewalls for disc groove sidewall engagement when said tip is received in said disc groove, and a conductive electrode, affixed to said insulating support in a location substantially centered with respect to said insulating sidewalls, and presenting a surface to the bottom of said stylus tip, said conductive electrode having a lateral dimension in a direction extending between said insulating sidewalls, which is sufficiently foreshortened relative to the distance between said insulating sidewalls to preclude disc groove sidewall engagement by said conductive electrode when said stylus tip is received in said disc groove; means for establishing relative motion between said disc groove and said stylus tip under conditions of reception of said stylus tip within said disc groove; conductive means in proximity to said information track; and means responsive to capacitance variations exhibited between said stylus electrode and said conductive means during said motion for providing an electrical signal representative of said recorded information.

Claim 17

A high-density information record playback system comprising the combination of: a disc of thermoplastic material; said disc having a constant-width spiral groove in a surface thereof, the center-to-center spacing of successive convolutions thereof being substantially constant and independent of recorded information; said groove containing an information track constituted by variations in the geometry of the bottom of the groove representative of recorded information, and having sidewalls of a configuration which is substantially constant throughout said successive convolutions and independent of the groove bottom geometry variation representative of recorded information; a stylus having a tip subject to reception in said disc groove; said stylus including a support of insulating material providing the tip of said stylus with insulating sidewalls for disc groove sidewall engagement when said tip is received in said disc groove, and a conductive electrode, affixed to said insulating support in a location substantially centered with respect to said insulating sidewalls, and presenting a surface to the bottom of said stylus tip, said conductive electrode having a lateral dimension in a direction extending between said insulating sidewalls, which is sufficiently foreshortened relative to the distance between said insulating sidewalls to preclude disc groove sidewall engagement by said conductive electrode when said stylus tip is received in said disc groove; means for establishing relative motion between said disc groove and said stylus under conditions of substantially constant-depth reception of said stylus tip within said disc groove; conductive means in proximity to said information track; a resonant circuit incorporating the capacitance exhibited between said stylus electrode surface and said conductive means; a source of oscillations; means for applying oscillations from said source to said resonant circuit; and means including an amplitude detector coupled to said resonant circuit for developing a signal representative of said recorded information as said capacitance varies during said motion.

Claim 18

A high-density information record playback system comprising the combination of: a disc of thermoplastic material; said disc having a constant-width spiral groove in a surface thereof, the center-to-center spacing of successive convolutions thereof being substantially constant and independent of recorded information; said groove containing an information track constituted by variations in the geometry of the bottom of the groove representative of recorded information, and having sidewalls of a configuration which is substantially constant throughout said successive convolutions and independent of the groove bottom geometry variation representative of recorded information; a stylus having a tip subject to reception in said disc groove; said stylus including a support of insulating material providing the tip of said stylus with insulating sidewalls for disc groove sidewall engagement when said tip is received in said disc groove, and a conductive electrode, affixed to said insulating support in a location substantially centered with respect to said insulating sidewalls, and presenting a surface to the bottom of said stylus tip, said conductive electrode having a lateral dimension in a direction extending between said insulating sidewalls, which is sufficiently foreshortened relative to the distance between said insulating sidewalls to preclude disc groove sidewall engagement by said conductive electrode when said stylus tip is received in said disc groove; means for establishing relative motion between said disc groove and said stylus under conditions of substantially constant-depth reception of said stylus tip within said disc groove; conductive means in proximity to said information track; a resonant circuit incorporating the capacitance exhibited between said stylus electrode surface and said conductive means; a source of oscillations; means for applying oscillations from said source to said resonant circuit; and means including an amplitude detector coupled to said resonant circuit for developing a signal representative of said recorded information as said capacitance varies during said motion.

Claim 19

A high-density information record playback system comprising the combination of: a disc of thermoplastic insulating material; said disc having a constant-width spiral groove in a surface thereof, the center-to-center spacing of successive convolutions thereof being substantially constant and independent of recorded information; said groove containing an information track constituted by variations in the geometry of the bottom of the groove below groove s1dewalls of substantially invariant geometry; a stylus, including a support of insulating material providing the tip of said stylus with insulating sidewalls for disc groove sidewall engagement, and a conductive electrode, secured to said insulating support, said conductive electrode having a lateral dimension in a direction extending between said insulating sidewalls, which is sufficiently foreshortened relative to the distance between said insulating sidewalls to preclude disc groove sidewall engagement by said conductive electrode when said stylus tip is received in said disc groove and having a surface exposed at the bottom of said stylus tip, said electrode surface having a greater dimension in said lateral direction extending between said stylus sidewalls and a lesser dimension in a direction transverse to said lateral direction; means for establishing relative motion between said disc groove and said stylus tip under conditions of substantially constant-depth reception of said stylus tip within said disc groove, said Motion establishing means including a disc-supporting turntable having a conductive surface; and means responsive to capacitance variations exhibited between said stylus electrode surface and said conductive turntable surface during said motion for providing an electrical signal representative of recorded information.

Claim 20

A high-density information record playback system comprising the combination of: a disc of thermoplastic insulating material; said disc having a constant-width spiral groove in a surface thereof, the center-to-center spacing of successive convolutions thereof being substantially constant and independent of recorded information; said groove containing an information track constituted by variations in the geometry of the bottom of the groove below groove s1dewalls of substantially invariant geometry; a stylus, including a support of insulating material providing the tip of said stylus with insulating sidewalls for disc groove sidewall engagement, and a conductive electrode, secured to said insulating support, said conductive electrode having a lateral dimension in a direction extending between said insulating sidewalls, which is sufficiently foreshortened relative to the distance between said insulating sidewalls to preclude disc groove sidewall engagement by said conductive electrode when said stylus tip is received in said disc groove and having a surface exposed at the bottom of said stylus tip, said electrode surface having a greater dimension in said lateral direction extending between said stylus sidewalls and a lesser dimension in a direction transverse to said lateral direction; means for establishing relative motion between said disc groove and said stylus tip under conditions of substantially constant-depth reception of said stylus tip within said disc groove, said Motion establishing means including a disc-supporting turntable having a conductive surface; and means responsive to capacitance variations exhibited between said stylus electrode surface and said conductive turntable surface during said motion for providing an electrical signal representative of recorded information.

Claim 21

Apparatus in accordance with claim 10 wherein said information track comprises a succession of relatively raised and relatively lowered regions of said insulating material along the length of said groove bottom, the relative dimensioning of said stylus sidewalls and said disc groove sidewalls and the dimensioning of said information track being such as to substantially preclude mechanical disturbance of said stylus tip by said groove bottom regions during said motion.

Claim 22

Playback apparatus, for use with a grooved video disc, comprising the combination of: a stylus including a tip having insulating sidewalls for disc groove sidewall engagement when received in a video disc groove, said insulating sidewalls being constituted by opposite edges of a support element of insulating material; said stylus tip also including a conductive electrode, secured to said insulating support element in a location centrally positioned with respect to said insulating sidewalls, and having a surface exposed at the bottom of said stylus tip, said conductive electrode having a lateral dimension, in a direction extending between said insulating sidewalls, which is foreshortened relative to the distance between said insulating sidewalls so as to preclude disc groove sidewall engagement by said conductive electrode when said tip is received in a video disc groove; a turntable for supporting a video disc in a playing position permitting disc groove reception of said stylus tip; means for rotating said turntable for establishment of relative motion between said disc groove and stylus tip; and means electrically coupled to said stylus electrode for developing an electrical signal representative of information recorded on said video disc when said relative motion occurs.

Claim 23

Playback apparatus, for use with a grooved video disc, comprising the combination of: a stylus including a tip having insulating sidewalls for disc groove sidewall engagement when received in a video disc groove, said insulating sidewalls being constituted by opposite edges of a support element of insulating material; said stylus tip also including a conductive electrode, secured to said insulating support element in a location centrally positioned with respect to said insulating sidewalls, and having a surface exposed at the bottom of said stylus tip, said conductive electrode having a lateral dimension, in a direction extending between said insulating sidewalls, which is foreshortened relative to the distance between said insulating sidewalls so as to preclude disc groove sidewall engagement by said conductive electrode when said tip is received in a video disc groove; a turntable for supporting a video disc in a playing position permitting disc groove reception of said stylus tip; means for rotating said turntable for establishment of relative motion between said disc groove and stylus tip; and means electrically coupled to said stylus electrode for developing an electrical signal representative of information recorded on said video disc when said relative motion occurs.

Claim 24

Playback apparatus, for use with a grooved video disc, comprising the combination of: a stylus including a tip having insulating sidewalls for disc groove sidewall engagement when received in a video disc groove, said insulating sidewalls being constituted by opposite edges of a support element of insulating material; said stylus tip also including a conductive electrode, secured to said insulating support element in a location centrally positioned with respect to said insulating sidewalls, and having a surface exposed at the bottom of said stylus tip, said conductive electrode having a lateral dimension, in a direction extending between said insulating sidewalls, which is foreshortened relative to the distance between said insulating sidewalls so as to preclude disc groove sidewall engagement by said conductive electrode when said tip is received in a video disc groove; means, including a turntable, for supporting a video disc in a playing position permitting disc groove reception of said stylus tip and for presenting a reference conductive surface in proximity to said disc when in said playing position, said turntable being rotatable to establish relative motion between disc groove and stylus tip; and means electrically coupled to said stylus electrode and to said reference conductive surface for developing signal variations when said relative motion occurs.

Claim 25

Playback apparatus, for use with a grooved video disc, comprising the combination of: a stylus including a tip having insulating sidewalls for disc groove sidewall engagement when received in a video disc groove, said insulating sidewalls being constituted by opposite edges of a support element of insulating material; said stylus tip also including a conductive electrode, secured to said insulating support element in a location centrally positioned with respect to said insulating sidewalls, and having a surface exposed at the bottom of said stylus tip, said conductive electrode having a lateral dimension, in a direction extending between said insulating sidewalls, which is foreshortened relative to the distance between said insulating sidewalls so as to preclude disc groove sidewall engagement by said conductive electrode when said tip is received in a video disc groove; means, including a turntable, for supporting a video disc in a playing position permitting disc groove reception of said stylus tip and for presenting a reference conductive surface in proximity to said disc when in said playing position, said turntable being rotatable to establish relative motion between disc groove and stylus tip; and means electrically coupled to said stylus electrode and to said reference conductive surface for developing signal variations when said relative motion occurs.

Claim 26

Playback apparatus, for use with a grooved video disc, comprising the combination of: a stylus including a tip having insulating sidewalls for disc groove sidewall engagement when received in a video disc groove, said insulating sidewalls being constituted by opposite edges of a support element of insulating material; said stylus tip also including a conductive electrode, secured to said insulating support element in a location centrally positioned with respect to said insulating sidewAlls, and having a surface exposed at the bottom of said stylus tip, said conductive electrode having a lateral dimension, in a direction extending between said insulating sidewalls, which is foreshortened relative to the distance between said insulating sidewalls so as to preclude disc groove sidewall engagement by said conductive electrode when said tip is received in a video disc groove; means, including a turntable, for supporting a video disc in a playing position permitting disc groove reception of said stylus tip and for presenting a reference conductive surface in proximity to said disc when in said playing position, said turntable being rotatable to establish relative motion between disc groove and stylus tip; and an inductive element connected between said stylus electrode and said reference conductive surface; a source of relatively fixed-frequency oscillations coupled to said inductive element; and means for detecting variations in the amplitude of oscillations appearing across said inductive element when said motion occurs.

Claim 27

Playback apparatus, for use with a grooved video disc, comprising the combination of: a stylus including a tip having insulating sidewalls for disc groove sidewall engagement when received in a video disc groove, said insulating sidewalls being constituted by opposite edges of a support element of insulating material; said stylus tip also including a conductive electrode, secured to said insulating support element in a location centrally positioned with respect to said insulating sidewAlls, and having a surface exposed at the bottom of said stylus tip, said conductive electrode having a lateral dimension, in a direction extending between said insulating sidewalls, which is foreshortened relative to the distance between said insulating sidewalls so as to preclude disc groove sidewall engagement by said conductive electrode when said tip is received in a video disc groove; means, including a turntable, for supporting a video disc in a playing position permitting disc groove reception of said stylus tip and for presenting a reference conductive surface in proximity to said disc when in said playing position, said turntable being rotatable to establish relative motion between disc groove and stylus tip; and an inductive element connected between said stylus electrode and said reference conductive surface; a source of relatively fixed-frequency oscillations coupled to said inductive element; and means for detecting variations in the amplitude of oscillations appearing across said inductive element when said motion occurs.

Claim 28

A grooved video signal record playback system comprising: a video disc having, in a surface thereof, a spiral groove of a width which is substantially constant and independent of recorded information, the center-to-center spacing of successive convolutions of said spiral groove being independent of recorded information; said groove containing an information track constituted by variations in the geometry of the bottom of the groove representative of recorded video information, and having sidewalls of a configuration which is substantially constant throughout said successive convolutions and independent of the groove bottom geometry variations representative of recorded information; a stylus having a tip subject to reception in said disc groove during playback use; said stylus including a support of insulating material, and an electrode of conductive material secured to said insulating support, said electrode presenting a surface to the disc groove bottom when said tip is received in said disc groove, which surface has a greater dimension in a lateral direction extending between said groove sidewalls and a lesser dimension in a longitudinal direction along said groove and normal to said lateral direction; the substantially constant configuration of said groove sidewalls limiting the magnitude of attainable depth of stylus tip reception in said groove to a value which is the same for all regions of said groove throughout said successive convolutions and which is independent of the contents of said information track; a turntable for supporting said disc in a playing position permitting said disc groove reception of said stylus tip; means for rotating said turntable to establish relative motion between said disc groove and said stylus tip; and means electrically connected to said stylus electrode for developing an electrical signal representative of groove bottom geometry variations passing beneath said stylus electrode surface when said relative motion occurs.

Claim 29

A grooved video signal record playback system comprising: a video disc having, in a surface thereof, a spiral groove of a width which is substantially constant and independent of recorded information, the center-to-center spacing of successive convolutions of said spiral groove being independent of recorded information; said groove containing an information track constituted by variations in the geometry of the bottom of the groove representative of recorded video information, and having sidewalls of a configuration which is substantially constant throughout said successive convolutions and independent of the groove bottom geometry variations representative of recorded information; a stylus having a tip subject to reception in said disc groove during playback use; said stylus including a support of insulating material, and an electrode of conductive material secured to said insulating support, said electrode presenting a surface to the disc groove bottom when said tip is received in said disc groove, which surface has a greater dimension in a lateral direction extending between said groove sidewalls and a lesser dimension in a longitudinal direction along said groove and normal to said lateral direction; the substantially constant configuration of said groove sidewalls limiting the magnitude of attainable depth of stylus tip reception in said groove to a value which is the same for all regions of said groove throughout said successive convolutions and which is independent of the contents of said information track; a turntable for supporting said disc in a playing position permitting said disc groove reception of said stylus tip; means for rotating said turntable to establish relative motion between said disc groove and said stylus tip; and means electrically connected to said stylus electrode for developing an electrical signal representative of groove bottom geometry variations passing beneath said stylus electrode surface when said relative motion occurs.

Claim 30

A grooved video signal record playback system comprising: a video disc record of thermoplastic material; said disc record having, in a surface thereof, a spiral groove of a width which is substantially constant and independent of recorded information, the center-to-center spacing of successive convolutions of said spiral groove being independent of recorded information; said groove containing an information track constituted by variations in the geometry of the bottom of the groove representative of recorded video information, and having sidewalls of a configuration which is substantially constant throughout said successive convolutions and independent of the groove bottom geometry variations representative of recorded information; a stylus having a tip subject to reception in said disc groove during playback use; said stylus including a support of insulating material, and an electrode of conDuctive material secured to said insulating support, said electrode presenting a surface to the disc groove bottom when said tip is received in said disc groove, which surface has a greater dimension in a lateral direction extending between said groove sidewalls and a lesser dimension in a longitudinal direction along said groove and normal to said lateral direction; the substantially constant configuration of said groove sidewalls limiting the magnitude of attainable depth of stylus tip reception in said groove to a value which is the same for all regions of said groove throughout said successive convolutions and which is indepenent of the contents of said information track; said groove bottom geometry variations in the groove of said thermoplastic disc comprising variations in the depth of said groove in a region centrally disposed relative to said sidewalls, said depth variations being limited to a range of depths exceeding said magnitude of attainable depth of stylus tip reception; a turntable for supporting said disc in a playing position permitting said disc groove reception of said stylus tip; means for establishing relative motion between said disc groove and said stylus tip under conditions of substantially constant depth reception of said stylus tip within said disc groove, said motion establishing means comprising means for rotating said disc-supporting turntable; and means electrically connected to said stylus electrode for developing an electrical signal representative of groove bottom depth variations passing beneath said stylus electrode surface when said relative motion occurs.

Claim 31

A grooved video signal record playback system comprising: a video disc record of thermoplastic material; said disc record having, in a surface thereof, a spiral groove of a width which is substantially constant and independent of recorded information, the center-to-center spacing of successive convolutions of said spiral groove being independent of recorded information; said groove containing an information track constituted by variations in the geometry of the bottom of the groove representative of recorded video information, and having sidewalls of a configuration which is substantially constant throughout said successive convolutions and independent of the groove bottom geometry variations representative of recorded information; a stylus having a tip subject to reception in said disc groove during playback use; said stylus including a support of insulating material, and an electrode of conDuctive material secured to said insulating support, said electrode presenting a surface to the disc groove bottom when said tip is received in said disc groove, which surface has a greater dimension in a lateral direction extending between said groove sidewalls and a lesser dimension in a longitudinal direction along said groove and normal to said lateral direction; the substantially constant configuration of said groove sidewalls limiting the magnitude of attainable depth of stylus tip reception in said groove to a value which is the same for all regions of said groove throughout said successive convolutions and which is indepenent of the contents of said information track; said groove bottom geometry variations in the groove of said thermoplastic disc comprising variations in the depth of said groove in a region centrally disposed relative to said sidewalls, said depth variations being limited to a range of depths exceeding said magnitude of attainable depth of stylus tip reception; a turntable for supporting said disc in a playing position permitting said disc groove reception of said stylus tip; means for establishing relative motion between said disc groove and said stylus tip under conditions of substantially constant depth reception of said stylus tip within said disc groove, said motion establishing means comprising means for rotating said disc-supporting turntable; and means electrically connected to said stylus electrode for developing an electrical signal representative of groove bottom depth variations passing beneath said stylus electrode surface when said relative motion occurs.

Claim 32

A stylus, for use in playback of a grooved disc recording, said stylus comprising: a support of insulating material providing the tip of said stylus with insulating sidewalls, the spacing therebetween being such as to permit disc groove sidewall engagement by said insulating sidewalls in said playback use; and a conductive electrode, secured to said insulating support in a location substantially centered with respect to said insulating sidewalls, and having a surface exposed at the bottom of said stylus tip, said conductive electrode having a lateral dimension, in a direction extending between said insulating sidewalls, which is reduced relative to the distance between said insulating sidewalls whereby disc groove sidewall engagement by said conductive electrode is precluded, said electrode terminating at the bottom of said stylus tip in said exposed surface which has a greater dimension in said lateral direction extending between said stylus sidewalls and a lesser dimension in a direction transverse to said lateral direction, said lesser dimension being of the order of one micrometer.

Claim 33

A stylus, for use in playback of a grooved disc recording, said stylus comprising: a support of insulating material providing the tip of said stylus with insulating sidewalls, the spacing therebetween being such as to permit disc groove sidewall engagement by said insulating sidewalls in said playback use; and a conductive electrode, secured to said insulating support in a location substantially centered with respect to said insulating sidewalls, and having a surface exposed at the bottom of said stylus tip, said conductive electrode having a lateral dimension, in a direction extending between said insulating sidewalls, which is reduced relative to the distance between said insulating sidewalls whereby disc groove sidewall engagement by said conductive electrode is precluded, said electrode terminating at the bottom of said stylus tip in said exposed surface which has a greater dimension in said lateral direction extending between said stylus sidewalls and a lesser dimension in a direction transverse to said lateral direction, said lesser dimension being of the order of one micrometer.

Claim 34

In combination: a disc of thermoplastic material; said disc having, in a surface thereof, a spiral groove of a width which is substantially constant and independent of recorded information, the center-to-center spacing of successive convolutions of said spiral groove being independent of recorded information; said groove containing an information track constituted by variations in the geometry of the bottom of the groove representative of recorded information, and having sidewalls of a configuration which is substantially constant throughout said successive convolutions and independent of the groove bottom geometry variation representative of recorded information; a stylus having a tip subject to reception in said disc groove; said stylus including a support of insulating material providing the tip of said stylus with insulating sidewalls dimensioned for disc groove sidewall engagement, and a conductive electrode, affixed to said insulating support in a location substantially centered with respect to said insulating sidewalls, and having a surface exposed at the bottom of said stylus tip, said conductive electrode having a lateral dimension, in a direction extending between said insulating sidewalls, which is reduced relative to thE distance between said insulating sidewalls to a degree precluding disc groove sidewall engagement by said conductive electrode when said stylus tip is received in said disc groove; the substantially constant configuration of said disc groove sidewalls limiting the depth of stylus tip reception in said groove to a magnitude which is the same for all regions of said groove throughout said successive convolutions and which is independent of the contents of said information track; said groove bottom geometry variations in the groove of said thermoplastic disc comprising variations in the depth of said groove in a region centrally disposed relative of said sidewalls, said depth variations being limited to a range of depths exceeding said limited magnitude of depth of stylus tip reception; a turntable for supporting said disc in a playing position permitting said disc groove reception of said stylus tip; means for rotating said turntable for establishment of relative motion between disc groove and stylus tip; and means, including a conductor connected to said stylus electrode, for developing an electrical signal representative of said recorded information when said relative motion occurs.

Claim 35

In combination: a disc of thermoplastic material; said disc having, in a surface thereof, a spiral groove of a width which is substantially constant and independent of recorded information, the center-to-center spacing of successive convolutions of said spiral groove being independent of recorded information; said groove containing an information track constituted by variations in the geometry of the bottom of the groove representative of recorded information, and having sidewalls of a configuration which is substantially constant throughout said successive convolutions and independent of the groove bottom geometry variation representative of recorded information; a stylus having a tip subject to reception in said disc groove; said stylus including a support of insulating material providing the tip of said stylus with insulating sidewalls dimensioned for disc groove sidewall engagement, and a conductive electrode, affixed to said insulating support in a location substantially centered with respect to said insulating sidewalls, and having a surface exposed at the bottom of said stylus tip, said conductive electrode having a lateral dimension, in a direction extending between said insulating sidewalls, which is reduced relative to thE distance between said insulating sidewalls to a degree precluding disc groove sidewall engagement by said conductive electrode when said stylus tip is received in said disc groove; the substantially constant configuration of said disc groove sidewalls limiting the depth of stylus tip reception in said groove to a magnitude which is the same for all regions of said groove throughout said successive convolutions and which is independent of the contents of said information track; said groove bottom geometry variations in the groove of said thermoplastic disc comprising variations in the depth of said groove in a region centrally disposed relative of said sidewalls, said depth variations being limited to a range of depths exceeding said limited magnitude of depth of stylus tip reception; a turntable for supporting said disc in a playing position permitting said disc groove reception of said stylus tip; means for rotating said turntable for establishment of relative motion between disc groove and stylus tip; and means, including a conductor connected to said stylus electrode, for developing an electrical signal representative of said recorded information when said relative motion occurs.

Claim 36

In combination: a disc of thermoplastic material; said disc having, in a surface thereof, a spiral groove of a width which is substantially constant and independent of recorded information, the center-to-center spacing of successive convolutions of said spiral groove being independent of recorded information; said groove containing an information track constituted by variations in the geometry of the bottom of the groove representative of video signal information, and having sidewalls of a configuration which is substantially constant throughout said successive convolutions and independent of the groove bottom geometry variations, said groove bottom geometry variations comprising variations in the depth of said groove in a region centrally disposed relative to said groove sidewalls; a stylus having a tip subject to reception in said disc groove; said stylus tip having insulating sidewalls for disc groove sidewall engagement when said tip is received in said disc groove, said insulating sidewalls being constituted by opposite edges of a support element of insulating material, and a conductive electrode, supported by said insulating support element, and having a surface exposed at the bottom of said stylus tip, a turntable for supporting said disc in a playing position permitting said disc groove reception of said stylus tip; means for rotating said turntable for establishment of relative motion between disc groove and stylus tip; and means conductively connected to said stylus electrode for developing an electrical signal representative of said recorded information when said relative motion occurs.

Claim 37

In combination: a disc of thermoplastic material; said disc having, in a surface thereof, a spiral groove of a width which is substantially constant and independent of recorded information, the center-to-center spacing of successive convolutions of said spiral groove being independent of recorded information; said groove containing an information track constituted by variations in the geometry of the bottom of the groove representative of video signal information, and having sidewalls of a configuration which is substantially constant throughout said successive convolutions and independent of the groove bottom geometry variations, said groove bottom geometry variations comprising variations in the depth of said groove in a region centrally disposed relative to said groove sidewalls; a stylus having a tip subject to reception in said disc groove; said stylus tip having insulating sidewalls for disc groove sidewall engagement when said tip is received in said disc groove, said insulating sidewalls being constituted by opposite edges of a support element of insulating material, and a conductive electrode, supported by said insulating support element, and having a surface exposed at the bottom of said stylus tip, a turntable for supporting said disc in a playing position permitting said disc groove reception of said stylus tip; means for rotating said turntable for establishment of relative motion between disc groove and stylus tip; and means conductively connected to said stylus electrode for developing an electrical signal representative of said recorded information when said relative motion occurs.

Claim 38

Playback apparatus, for use with a grooved video disc, comprising the combination of: a stylus having a tip subject to reception in the groove of a video disc; said stylus including a support of insulating material providing the tip of said stylus with insulating sidewalls, the spacing therebetween being such as to permit disc groove sidewall engagement by said insulating sidewalls in said playback use; said stylus tip also including a conductive electrode, secured to said insulating support, said electrode presenting a surface to the disc groove bottom when said tip is received in said disc groove, which surface has a greater dimension in a lateral direction extending between said stylus sidewalls and a lesser dimension in a direction transverse to said lateral direction, said lesser dimension being approximately 1 micrometer; a turntable for supporting a video disc in a playing position permitting disc groove reception of said stylus tip; means for rotating said turntable for establishment of relative motion between disc groove and stylus tip; and means conductively connected to said stYlus electrode for developing an electrical signal representative of information recorded on said video disc when said relative motion occurs.

Claim 39

Playback apparatus, for use with a grooved video disc, comprising the combination of: a stylus having a tip subject to reception in the groove of a video disc; said stylus including a support of insulating material providing the tip of said stylus with insulating sidewalls, the spacing therebetween being such as to permit disc groove sidewall engagement by said insulating sidewalls in said playback use; said stylus tip also including a conductive electrode, secured to said insulating support, said electrode presenting a surface to the disc groove bottom when said tip is received in said disc groove, which surface has a greater dimension in a lateral direction extending between said stylus sidewalls and a lesser dimension in a direction transverse to said lateral direction, said lesser dimension being approximately 1 micrometer; a turntable for supporting a video disc in a playing position permitting disc groove reception of said stylus tip; means for rotating said turntable for establishment of relative motion between disc groove and stylus tip; and means conductively connected to said stYlus electrode for developing an electrical signal representative of information recorded on said video disc when said relative motion occurs.