Information recording and reproducing apparatus provided with means for adding to a tracking signal offset corresponding to the positional deviation of a recording spot and a reproducing spot

An apparatus for effecting the recording of information on and reproduction of information from an information track on a recording medium, comprising:

• a first light source which emits a first light beam upon recording and which does not emit the first light beam upon reproduction;
• a second light source which emits a second light beam upon both recording and during reproduction;
• a beam splitter for combining the first and second light beams together;
• an optical system for condensing the first and second light beams to apply a first light spot and a second light spot comprising at least one light spot to the information track on the recording medium, wherein upon recording, the first and second light spots are applied to the information track to record the information with the first light spot simultaneously with detecting a tracking signal from the second light spot and upon reproduction, the information is reproduced with the second light spot simultaneously with detecting the tracking signal from the second light spot;
• means for moving the recording medium relative to the first and second light spots in the lengthwise direction of the information track;
• a photosensor for receiving reflected light from the recording medium, caused upon the application of the second light spot to the recording medium;
• a tracking control circuit for detecting a tracking signal from an output from the photosensor;
• an actuator for driving at least a part of said optical system in conformity with the tracking signal to thereby move the first and second light spots in a tracking direction orthogonal to the lengthwise direction of the information track;
• and
• means for imparting to the tracking signal an offset corresponding to a positional deviation between the center of the first light spot an the center of the second light spot in the tracking direction upon recording, wherein said offset imparting means does not impart any offset to the tracking signal upon reproduction.

An apparatus for effecting the recording and reproduction of information on a recording medium alternately provided with a plurality of information tracks and a plurality of tracking tracks, comprising:

• a first light source emitting a light beam for recording;
• a second light source emitting a light beam for reproduction and first and second light beams for tracking;
• a beam splitter for combining the light beam for recording, the light beam for reproduction and the first and second light beams for tracking together;
• an objective lens for condensing the light beam for recording, the light beam for reproduction and the first and second light beams for tracking combined together and applying these light beams as a recording spot, a reproducing spot and first and second tracking spots, respectively, to the information tracks, the recording spot and the reproducing spot being applied to one of said plurality of information tracks, the first tracking spot being applied to the tracking track disposed on one side of one of the information tracks, the second tracking spot being applied to the tracking track disposed on the other side of said one of the information tracks;
• means for moving the recording medium relative to the recording spot, the reproducing spot and the first and second tracking spots in the lengthwise direction of the information tracks;
• first and second optical sensors for receiving the reflected lights of the first and second tracking spots, respective, reflected by the recording medium;
• a tracking control circuit for differentiating the outputs of the first and second optical sensors to thereby detect a tracking signal;
• an actuator for moving the objective lens in the tracking direction orthogonal to the lengthwise direction of the information tracks in conformity with the tracking signal;
• a third optical sensor for receiving the reflected light of the reproducing spot reflected by the recording medium;
• a reproduction circuit for reproducing the information from the output of the third optical sensor;
• and
• means for providing to the tracking signal an offset corresponding to the positional deviation between the center of the recording spot and the center of a reproducing spot in the tracking direction, during recording.

A method of effecting recording of information and reproduction of information by use of an apparatus comprising means for applying a first light spot and a second light spot comprising at least one light spot to an information track on a recording medium, means for moving the recording medium relative to the first and second light spots in the lengthwise direction of the information track, means for detecting a tracking signal from a reflected light from the recording medium, caused upon the application of the second light spot to the recording medium, tracking control means for moving the first and second light spots in a tracking direction orthogonal to the lengthwise direction of the information track according to the tracking signal, and means for imparting to the tracking signal an offset corresponding to a positional deviation between the center of the first light spot and the center of the second light spot in the tracking direction, said method comprising the steps of:

• upon recording, scanning the information track with the first and second light spots to record information with the first light spot;
• upon recording, detecting the tracking signal from the reflected light caused upon the application of the second light spot;
• upon recording, imparting an offset to the detected tracking signal;
• upon recording, effecting a tracking control of the first and second light spots by the tracking signal to which the offset has been imparted;
• upon reproduction, scanning the information track on which information has been recorded with the second light spot to reproduce the information;
• upon reproduction, detecting a tracking signal from a reflected light caused upon the application of the second light spot;
• and
• upon reproduction, effecting a tracking control of the second light spot with the tracking signal to which any offset is not imparted.

An apparatus for effecting recording of information on and reproduction of information from an information track on a recording medium, comprising:

• means for applying a first light spot to the information track to record information;
• means for applying a second light spot comprising at least one light spot to the information track to reproduce information;
• means for moving the recording medium relative to the first and second light spots in the lengthwise direction of the information track;
• means for detecting a tracking signal from reflected light reflected form the recording medium, caused upon the application of the second light spot to the recording medium;
• tracking control means for moving the first and second light spots in a tracking direction orthogonal to the lengthwise direction of the information tack according to the tracking signal;
• and
• means for imparting to the tracking signal an offset corresponding to a positional deviation between the center of the first light spot and the center of the second light spot in the tracking direction, wherein said offset imparting means imparts the offset to the tracking signal when the relative velocity between the recording medium and the light spot is constant, and said offset imparting means does not impart any offset to the tracking signal when the relative velocity between the recording medium and the light spot is being increased or decreased.

An apparatus for effecting the recording of information on and the reproduction of information from an information track on a recording medium, comprising:

• means for applying a first light spot to the information track and for recording the information with the first light spot;
• means for applying a second light spot comprising at least one light spot to the information track and for reproducing the information with the second light spot;
• means for moving the recording medium relative to the first and second light spots in the lengthwise direction of the information track;
• means for detecting a tracking signal from reflected light from the recording medium, caused by the application of the second light spot to the recording medium;
• tracking control means for moving the first and second light spots in a tracking direction orthogonal to the lengthwise direction of the information track in conformity with the tracking signal;
• and
• means for selectively imparting to the tracking signal an offset corresponding to a positional deviation between the center of the first light spot and the center of the second light spot in the tracking direction according to an operating state which is a recording state or a reproduction state.

An apparatus for effecting the recording of information on and the reproduction of information from an information track on a recording medium, comprising:

• a first light source which emits a first light beam upon recording and which does not emit a light beam upon reproduction;
• a second light source which emits a second light beam upon both recording and reproduction;
• a beam splitter for combining the first and second light beams together;
• an optical system for condensing the first and second light beams to apply a first light spot and a second light spot comprising at least one light spot to the information track on the recording medium, wherein upon recording, the first and second light spots are applied to the information track to record the information with the first light spot simultaneously with detecting a tracking signal from the second light spot, and upon reproduction, the information is reproduced with the second light spot simultaneously with detecting the tracking signal from the second light spot;
• means for moving the recording medium relative to the first and second light spots in the lengthwise direction of the information track;
• a photosensor for receiving reflected light form the recording medium, caused upon the application of the second light spot to the recording medium;
• a tracking control circuit for detecting a tracking signal from an output from said photosensor;
• an actuator for driving at least a part of said optical system in conformity with the tracking signal to thereby move the first and second light spots in a tracking direction orthogonal to the lengthwise direction of the information track;
• and
• means for selectively imparting to the tracking signal an offset corresponding to a positional deviation between the center of the first light spot and the center of the second light spot in the tracking direction according to an operating state which is a recording state or a reproduction state.