Digital servo control apparatus

Claim 2

A digital position control apparatus for controlling a position of an object to be controlled by digital information, comprising: detecting means for detecting the position of the object to be controlled; actuators to drive the object to be controlled; and a digital signal processing section to calculate controlled variables to said actuators in correspondence to the result of the detection of said detecting means, wherein the digital signal processing section does not calculate the controlled variables to the actuators in the case where the result of the detection of the detecting means is set into a predetermined state.

Claim 3

An apparatus according to claim 1, wherein the object to be controlled is an objective lens of an optical head in an optical disc information recording/reproducing apparatus.

Claim 4

A digital servo control apparatus for servo controlling a position of an object to be controlled by digital information, comprising: detecting means for detecting a deviation of the object to be controlled for a predetermined position; actuator means for driving the object to be controlled; and a digital signal processing section to calculate controlled variables to the actuator means in correspondence to the result of the detection of said detecting means, wherein said digital signal processing section does not calculate the controlled variables to the actuator means in the case where the result of the detection by said detecting means is set into a predetermined state.

Claim 5

A digital servo control apparatus for servo controlling a position of an object to be controlled by digital information, comprising: detecting means for detecting a deviation of the object to be controlled for a predetermined position; actuator means for driving the object to be controlled; and a digital signal processing section to calculate controlled variables to the actuator means in correspondence to the result of the detection of said detecting means, wherein said digital signal processing section does not calculate the controlled variables to the actuator means in the case where the result of the detection by said detecting means is set into a predetermined state.

Claim 6

An apparatus according to claim 3, wherein said object to be controlled is an objective lens of an optical head in an optical disc information recording/reproducing apparatus.

Claim 7

An apparatus according to claim 3, further having a comparator, and wherein said comparator discriminates whether the result of the detection is set into the predetermined state or not, and if it is decided that the detection result is in the predetermined state, the detection result is not sent to the digital signal processing section, and if it is decided that the detection result is not in the predetermined state, the detection result is sent to the digital signal processing section and the calculation is executed.

Claim 8

An apparatus according to claim 5, wherein said predetermined state is a state in which the deviation of the object to be controlled for the predetermined position is set to "0".

Claim 9

An apparatus according to claim 3, wherein said actuator means comprises a plurality of actuators to respectively drive the object to be controlled in different directions, and said digital signal processing section calculates the controlled variables to said plurality of actuators and outputs.

Claim 10

Optical disk recording apparatus of the kind which has means for automatically positioning an optical head (2) in a selected position in relation to an optical disk (1) both in terms of focussing and tracking, said means including tracking (3) and focussing (4) error signal generators and tracking (12) and focussing (13) actuators, the former (3, 4) being interconnected with the latter (12, 13) through a digital processing circuit (14) the purpose of which is to process the two error signals and feed correction signals to the actuators (12, 13) to move the optical head (2) in relation to the optical disk (1), characterised in that in order to reduce the response time of the error correction system there are means (107) to ensure that any signal from the detectors (103, 104) which is equivalent to zero error by-passes the digital signal processing circuit (108).

Claim 11

Optical disk recording apparatus of the kind which has means for automatically positioning an optical head (2) in a selected position in relation to an optical disk (1) both in terms of focussing and tracking, said means including tracking (3) and focussing (4) error signal generators and tracking (12) and focussing (13) actuators, the former (3, 4) being interconnected with the latter (12, 13) through a digital processing circuit (14) the purpose of which is to process the two error signals and feed correction signals to the actuators (12, 13) to move the optical head (2) in relation to the optical disk (1), characterised in that in order to reduce the response time of the error correction system there are means (107) to ensure that any signal from the detectors (103, 104) which is equivalent to zero error by-passes the digital signal processing circuit (108).