Direct access apparatus and method for video disc player

Claim 1

A direct access apparatus adapted for reproducing information stored on a disc-shaped recording medium of the type defining a plurality of interconnected recording tracks on a first surface thereof, said plurality of tracks comprising a continuous path capable of being tracked by a stylus means, said tracks each storing an identification code signal, said apparatus comprising; means for rotating said medium at a constant angular velocity; an arm mechanism moveable along at least one radius of said disc-shaped recording medium above and parallel to said first surface of said medium; arm position controlling means, operatively connected to said arm mechanism, for controlling the speed and direction of movement of said arm mechanism; stylus means, supported by said arm mechanism, for reproducing at an output thereof at least a code signal stored on one of said tracks when said stylus means is moved into a first position whereat said stylus means is in contact with said first surface to track said one recording track; lifter driving means for moving said stylus means from a second position whereat said stylus means is not in contact with said first surface to said first position in response to a stylus control signal; code signal detecting means, connected to receive the output of said stylus means, for detecting the code signal reproduced by said stylus means and for rejecting any other signals reproduced by said stylus means; arm position detecting means for detecting the position of said arm mechanism; time converting means, connected to receive the detected code signal produced by said code signal detecting means and the detected arm position produced by said arm position detecting means, for calculating, from the detected code signal, indicia of the time duration necessary for said stylus means to reach the position on the plurality of interconnected tracks corresponding to said detected code signal by tracking said path from a predetermined starting position while said medium is rotating at said constant angular velocity, and alternately for calculating said indicia of duration from said detected arm mechanism position in the absence of said detected code signal; first memory means for storing said calculated indicia of duration; first data selector means, operatively connected to said first memory means, for selectively reading said stored calculated indicia of duration; desired data generating means, manipulable by a user, for generating in response to user manipulation, at an output thereof, indicia of time duration necessary for said stylus means to reach a desired position, programmable by said user, on the plurality of interconnected recording tracks by tracking said path from said predetermined starting position while said medium is rotating at said constant angular velocity; second memory means, connected to said output of said desired data generating means, for storing the indicia of duration generated by said desired data generating means; correcting means, operatively connected to said second memory means, for changing said generated duration indicia produced by said generating means in response to at least the direction of movement of said arm mechanism; second data selector means, operatively connected to said second memory means, for selectively reading said stored changed indicia; comparator means, connected to receive, at one input thereof, said calculated indicia of duration read by said first data selector means and to receive, at another input thereof, said stored changed indicia read by said second data selector means, for producing a pulse whenever the indicia applied to said one input is equal to the indicia applied to said other input; and counting means, connected to receive the pulses produced by said comparator means, for counting said pulses and for applying said stylus control signal responsive to the value of said count, causing said lifter driving means to move said stylus means into contact with said first surface of said medium whenever said comparator means detects a coincidence between the calculated indicia of duration and the changed generated indicia of duration.

Claim 10

An apparatus for positioning a stylus means at a desired position on a discoid storage medium, said medium of the type having a plurality of sequential addresses stored on a surface thereof, each of said addresses including a value indicating the position on said medium at which said address is stored relative to a predetermined initial position on said medium, said apparatus comprising: means for rotating said medium at a nominal angular velocity; stylus means for reproducing information stored on said medium; means for inputting a value representing a desired position on said medium; means for moving said stylus means between a raised position whereat said stylus means is not in contact with said medium and a lowered position whereat said stylus means is in contact with said medium; means operatively connected to said stylus means for reading a position value stored at the position on said medium in registry with said contacting stylus means and for producing said read value at an output thereof; means connected to the output of said reading means for storing said read value; means for a determiing whether the value stored in said storing means differs from the value inputted by said inputting means by more than a selected one of a first predetermined amount and a second predetermined amount less than said first predetermined amount; means, operatively connected to said determining means, for displacing said stylus means in said raised position along a path parallel to said medium surface in a direction determined by the sign of the difference between said value stored by said storing means and said value inputted by said inputting means; means for changing the value stored by said storing means in response to the distance and direction said stylus means is displaced by said displacing means; and means for controlling said moving means to move said stylus means to said lowered position and for controlling said determining means to selected said second predetermined amount in response to a determination by said determining means that the stored value differs from the inputted value by less than said first predetermined amount, and for controlling said rotating means to temporarily rotate said medium at a first angular velocity exceeding said nominal angular velocity in response to a determination by said determining means that said stored value differs from said inputted value by more than said second predtermined amount.

Claim 11

An apparatus for positioning a stylus means at a desired position on a discoid storage medium, said medium of the type having a plurality of sequential addresses stored on a surface thereof, each of said addresses including a value indicating the position on said medium at which said address is stored relative to a predetermined initial position on said medium, said apparatus comprising: means for rotating said medium at a nominal angular velocity; stylus means for reproducing information stored on said medium; means for inputting a value representing a desired position on said medium; means for moving said stylus means between a raised position whereat said stylus means is not in contact with said medium and a lowered position whereat said stylus means is in contact with said medium; means operatively connected to said stylus means for reading a position value stored at the position on said medium in registry with said contacting stylus means and for producing said read value at an output thereof; means connected to the output of said reading means for storing said read value; means for a determiing whether the value stored in said storing means differs from the value inputted by said inputting means by more than a selected one of a first predetermined amount and a second predetermined amount less than said first predetermined amount; means, operatively connected to said determining means, for displacing said stylus means in said raised position along a path parallel to said medium surface in a direction determined by the sign of the difference between said value stored by said storing means and said value inputted by said inputting means; means for changing the value stored by said storing means in response to the distance and direction said stylus means is displaced by said displacing means; and means for controlling said moving means to move said stylus means to said lowered position and for controlling said determining means to selected said second predetermined amount in response to a determination by said determining means that the stored value differs from the inputted value by less than said first predetermined amount, and for controlling said rotating means to temporarily rotate said medium at a first angular velocity exceeding said nominal angular velocity in response to a determination by said determining means that said stored value differs from said inputted value by more than said second predtermined amount.

Claim 16

A method of positioning a stylus at a desired position on a discoid storage medium rotating at a nominal angular velocity, said medium of the type having a plurality of sequential addresses stored on a surface thereof, each of said addresses including a value indicating the position on said medium at which said address is stored relative to a predetermined position on said medium, said method comprising the steps of: (1) inputting a value representing a desired position on said medium; (2) moving a stylus from a raised position whereat said stylus is not in contact with said medium to a lower position whereat said stylus is in contact with said medium; (3) reading a position value address stored at the position on said medium in registry with said contacting stylus; (4) storing the value read by said reading step (3); (5) moving said stylus from said lowered position to said raised position; (6) determining whether the value stored by said storing step (4) differs from the value inputted by said inputting step (1) by more than a first predetermined amount; (7) if the determining step (6) determines that said stored value differs from the inputted value by more than said first predetermined amount, performing the following steps: (a) displacing said stylus in said raised position along the path parallel to the surface of said medium in a direction determined by the sign of the difference between said stored value and said inputted value, (b) changing the value stored by said storing storing step (4) in response to the distance and direction said stylus is displaced by said displacing step (a), and (c) repeating said steps (6) and (7); (8) if said determining step (6) determines the value stored by said storing step (4) does not differ from said inputted value by more than said first predetermined amount, performing the following steps: (d) repeating steps (2), (3) and (4), (e) determining whether the value stored by said repeated storing step (4) differs from the value inputted by said inputting step (1) by more than a second predetermined amount less than a said first predetermined amount, and (f) if the determining step (e) determines said stored value differs from said inputted value by more than said second predetermined amount, temporarily rotating said medium at a first angular velocity exceeding said nominal angular velocity, repeating said steps (3 ) and (4), and repeating said steps (e) and (f).

Claim 17

A method of positioning a stylus at a desired position on a discoid storage medium rotating at a nominal angular velocity, said medium of the type having a plurality of sequential addresses stored on a surface thereof, each of said addresses including a value indicating the position on said medium at which said address is stored relative to a predetermined position on said medium, said method comprising the steps of: (1) inputting a value representing a desired position on said medium; (2) moving a stylus from a raised position whereat said stylus is not in contact with said medium to a lower position whereat said stylus is in contact with said medium; (3) reading a position value address stored at the position on said medium in registry with said contacting stylus; (4) storing the value read by said reading step (3); (5) moving said stylus from said lowered position to said raised position; (6) determining whether the value stored by said storing step (4) differs from the value inputted by said inputting step (1) by more than a first predetermined amount; (7) if the determining step (6) determines that said stored value differs from the inputted value by more than said first predetermined amount, performing the following steps: (a) displacing said stylus in said raised position along the path parallel to the surface of said medium in a direction determined by the sign of the difference between said stored value and said inputted value, (b) changing the value stored by said storing storing step (4) in response to the distance and direction said stylus is displaced by said displacing step (a), and (c) repeating said steps (6) and (7); (8) if said determining step (6) determines the value stored by said storing step (4) does not differ from said inputted value by more than said first predetermined amount, performing the following steps: (d) repeating steps (2), (3) and (4), (e) determining whether the value stored by said repeated storing step (4) differs from the value inputted by said inputting step (1) by more than a second predetermined amount less than a said first predetermined amount, and (f) if the determining step (e) determines said stored value differs from said inputted value by more than said second predetermined amount, temporarily rotating said medium at a first angular velocity exceeding said nominal angular velocity, repeating said steps (3 ) and (4), and repeating said steps (e) and (f).