Method for tracking in an optical recording/reading apparatus, and corresponding apparatus

Method for tracking in an apparatus for reading from and/or writing to an optical recording medium, the apparatus having a tracking device, a photodetector having at least two light-sensitive areas and a phase comparator, the method comprising the steps of:

• using the phase comparator to compare phases of first and second input signals related to a first and a second of said at least two light-sensitive areas, respectively, and to produce first and second output signals, said output signals indicating amount of phase difference and sign of phase difference of said first and second input signals, and
• using the tracking device to control a scanning beam in a manner dependent on a tracking signal formed from both first and second output signals, and to generate a first control signal, which indicates that the scanning beam has crossed a track centre of the recording medium, and a second control signal which states whether that region of the recording medium which is currently detected by the scanning beam is a track or a region between two tracks;
• and which first and second control signals are used for controlling the tracking device during a track jump operation;
• wherein the second control signal is formed by statistically evaluating the magnitudes of individual time difference values which indicate the time differences between input signals of the phase comparator of the output signals of the phase comparator.

Method for tracking in an apparatus for reading from and/or writing to an optical recording medium, the apparatus having a tracking device, a photodetector having at least two light-sensitive areas and a chase comparator, the method comprising the steps of:

• using the phase comparator to compare phases of first and second input signals related to a first and a second of said at least two light-sensitive areas, respectively, and to produce first and second output signals, said output signals indicating amount of phase difference and sign of phase difference of said first and second input signals, and
• using the tracking device to control a scanning beam in a manner dependent on a tracking signal formed from both first and second output signals, and to generate a first control signal, which indicates that the scanning beam has crossed a track centre of the recording medium, and a second control signal, which states whether that region of the recording medium which is currently detected by the scanning beam is a track or a region between two tracks;
• and which first and second control signals are used for controlling the tracking device during a track jump operation,
• wherein the second control signal is corrected in accordance with a third control signal, the third control signal containing a statement about an edge sequence which is contained in the output signals of the phase comparator and is not intended to be taken into account in the generation of the second control signal.

Method for tracking in an apparatus for reading from and/or writing to an optical recording medium, the apparatus having a tracking device, a photodetector having at least two light-sensitive areas and a phase comparator, the method comprising the steps of:

• using the phase comparator to compare phases of first and second input signals related to a first and a second of said at least two light-sensitive areas, respectively, and to produce first and second output signals, said output signals indicating amount of phase difference and sign of phase difference of said first and second input signals, and
• using the tracking device to control a scanning beam in a manner dependent on a tracking signal formed from both first and second output signals, and to generate a first control signal, which indicates that the scanning beam has crossed a track centre of the recording medium, and a second control signal, which states whether that region of the recording medium which is currently detected by the scanning beam is a track or a region between two tracks;
• and which first and second control signals are used for controlling the tracking device during a track jump operation,
• wherein said first output signal indicates the amount of phase difference between said first input signal and said second input signal, and said second output signal indicates which of said first and second input signal leads in phase.

Apparatus for reading from and/or writing to an optical recording medium, the apparatus comprising:

• a tracking device, a photodetector having at least two light-sensitive areas and a phase comparator for tracking a scanning beam of the apparatus in accordance with the differential phase detection method, said phase comparator having first and second input signals related to a first and a second of said at least two light-sensitive areas, respectively, and providing first and second output signals indicating amount of phase difference and sign of phase difference of said first and second input signals, and
• means for generating a tracking signal from both of said first and second output signals, wherein provision is made of a first signal generation device for generating a first control signal, which indicates that the scanning beam has crossed a track centre of the recording medium, in a manner dependent on both first and second output signals of the phase comparator, and wherein provision is made of a second signal generation device for generating a second control signal, which states whether that region of the recording medium which is currently detected by the scanning beam is a track or a region between two tracks, in a manner dependent on the same first and second output signals of the phase comparator,
• wherein the tracking device is to be controlled during a track jump operation in a manner dependent on the first control signal and the second control signal,
• wherein the second signal generation device is configured in such a way that the second control signal is generated by a statistical evaluation of the magnitudes, which indicate the time differences between input signals of the phase comparator, of individual time difference values of the output signals of the phase comparator.

Apparatus for reading from and/or writing to an optical recording medium, the apparatus comprising:

• a tracking device a photodetector having at least two light-sensitive areas and a phase comparator for tracking a scanning beam of the apparatus in accordance with the differential phase detection method, said phase comparator having first and second input signals related to a first and a second of said at least two light-sensitive areas, respectively, and providing first and second output signals indicating amount of phase difference and sign of phase difference of said first and second input signals, and
• means for generating a tracking signal from both of said first and second output signals, wherein provision is made of a first signal generation device for generating a first control signal, which indicates that the scanning beam has crossed a track centre of the recording medium, in a manner dependent on both first and second output signals of the phase comparator, and wherein provision is made of a second signal generation device for generating a second control signal, which states whether that region of the recording medium which is currently detected by the scanning beam is a track or a region between two tracks, in a manner dependent on the same first and second output signals of the phase comparator,
• wherein the tracking device is to be controlled during a track jump operation in a manner dependent on the first control signal and the second control signal,
• wherein provision is made of a correction signal generation device for generating a third control signal, which contains a statement about edge sequences which are contained in the output signals of the phase comparator and are not intended to be taken into account in the generation of the second control signal.

Apparatus for reading from and/or writing to an optical recording medium, the apparatus comprising:

• a tracking device, a photodetector having at least two light-sensitive areas and a phase comparator for tracking a scanning beam of the apparatus in accordance with the differential phase detection method, said phase comparator having first and second input signals related to a first and a second of said at least two light-sensitive areas, respectively, and providing first and second output signals indicating amount of phase difference and sign of phase difference of said first and second input signals, and
• means for generating a tracking signal from both of said first and second output signal, wherein provision is made of a first signal generation device for generating a first control signal, which indicates that the scanning beam has crossed a track centre of the recording medium, in a manner dependent on both first and second output signals of the phase comparator, and wherein provision is made of a second signal generation device for generating a second control signal which states whether that region of the recording medium which is currently detected by the scanning beam is a track or a region between two tracks, in a manner dependent on the same first and second output signals of the phase comparator,
• wherein the tracking device is to be controlled during a track ump operation in a manner dependent on the first control signal and the second control signal,
• wherein said first output signal indicates the amount of a phase difference between said first input signal and said second input signal, and said second output signal indicates which of said first and second input signal leads in phase.