Audio-visual playback apparatus and a sound and picture disc adapted therefor

Claim 2

An audio-visual playback apparatus for transparent picture images and sound recordings disposed in a spiral strip around the center of a disc which is rotatable at a constantly varying speed corresponding to a uniform playing speed, comprising a pickup arm for a picture pickup, leadscrews located adjacent one side of said disc for advancing said arm synchronously with disc rotation radially of the spiral, a light source positioned adjacent the opposite side of said disc, a pickup head on said pickup arm to pick up both the picture and sound signals, a control track running along said disc parallel to and immediately alongside a picture track and a sound track, a pickup provided on said pickup arm for transforming into electrical pulses optical control signals from said control track, a picture transmitting objective, and means for displacing said picture transmitting objective axially by magnetic fields modulated by said signals so that the distance between the picture plane in said disc and the objecTive is held constant against disc movements in the direction of the optical axis.

Claim 3

A playback apparatus as claimed in claim 1, comprising a. a lid and a rod-shaped light source fixed rigidly in said lid and subtending the radius of the disc and emitting three parallel strips of light at right angles to the disc surface; b. a rotatably mounted disc disposed under said light source and carrying the picture track, the sound track and the control track; c. said pickup head being guidably mounted on said pickup arm under said disc and incorporating, one behind the other in the direction of disc movement and registering with the corresponding sound, picture and control tracks on said disc, a picture pickup and a sound pickup, so that a picture on said picture track and the corresponding sections of said sound track and said control track are all picked up simultaneously; d. an aperture for said control track, a surface of said pickup head in which said aperture is located, to admit a short section of said control track, which constitutes a continuous transparent strip of constant width, a cylindrical lens disposed under said aperture at an angle of 45* to said control track, to form an image of said short section of the control track in the plane of two photodetectors so disposed that an increasing amount of light falls on one of them when said disc moves away from said cylindrical lens and on the other when said disc moves nearer thereto; e. two solenoids disposed round said picture-transmitting objective and controlled by said photodetectors, whose magnetic fields displace said objective axially in the direction of the optical axis, in the two opposite directions corresponding to the movements of said disc; and f. a condenser in a same mounting as the objective and movable axially therewith, to collimate the divergent beam from said objective.

Claim 4

A playback apparatus as claimed in claim 2, wherein a rotatable prism with an even number of sidefaces is placed in the path of the beam from said picture pickup to compensate the picture movement.

Claim 5

A playback apparatus as claimed in claim 3, wherein said collimated beam from said picture pickup is directed on to a television camera for black-and-white pictures or a triple-tube camera derived in its image plane from the picture formed from said picture pickup by interposing color-filter mirrors to split up the original picture.

Claim 6

A playback apparatus as claimed in claim 1, wherein a common driving system is provided for a disc table and said pickup arm controlling the rotary speed so that the playing speed for said tracks on said disc can be regulated.

Claim 7

A playback apparatus as claimed in claim 1, comprising a driving shaft, a spool fitted on said driving shaft, a tape wound or unwound onto or from said spool by a motor rotatable at a constant angular speed, which motor drives said disc table and said leadscrews.

Claim 8

A playback apparatus as claimed in claim 6, wherein said disc table is provided with a magnetic core.

Claim 9

A playback apparatus as claimed in claim 6, wherein said disc table is provided with driving pins.

Claim 10

A playback apparatus as claimed in claim 1, wherein said sound track is of the optical type.

Claim 11

A playback apparatus as claimed in claim 1, wherein said control track is of the optical type.

Claim 12

A playback apparatus as claimed in claim 9, wherein the information-carrying layer of said disc is protected on both sides by a sealing film of completely transparent material.

Claim 13

A playback apparatus as claimed in claim 7, wherein said disc is provided with a central sheet metal element.

Claim 14

A playback apparatus as claimed in claim 8, provided with non-interchangeable perforations.