Control apparatus and optical disk apparatus

A tracking control apparatus for controlling an optical head comprising a converging part for converging and irradiating an optical beam onto an information storage medium having a first address and a second address shifted from an information track toward the inner radius side and outer radius side by approximately ½ track, respectively to perform optical recording and/or reproduction on the information storage medium, an optical detecting part for dividing and detecting reflected light of the optical beam obtained from the information storage medium and a moving part for moving the converging part across the information track, the tracking control apparatus comprising:

• a difference signal generating part for generating a difference signal of each detected signal divided and detected by the optical detecting part;
• a first gate generating part for comparing the output of the difference signal generating part with a predetermined first level and generating a gate;
• a second gate generating part for comparing the output of the difference signal generating part with a predetermined second level and generating a gate;
• a lens position characteristic measuring part for successively generating offset set values for moving the position of the converging part using the moving part at predetermined spatial intervals and determining a measuring count based on the number of gates generated by the first gate generating part and the number of gates generated by the second gate generating part at respective positions to which the converging part has been moved;
• and
• a lens shift adjusting part for searching for the measuring count when a position shift of the converging part with respect to the optical detecting part reaches a minimum and moving the converging part using the moving part based on the offset set value corresponding to the searched measuring count.

A tracking control apparatus for controlling an optical head comprising a converging part for converging and irradiating an optical beam onto an information storage medium having a first address and a second address shifted from an information track toward the inner radius side and outer radius side by approximately ½ track, respectively to perform optical recording and/or reproduction on the information storage medium, an optical detecting part for dividing and detecting reflected light of the optical beam obtained from the information storage medium and a moving part for moving the converging part across the information track, the tracking control apparatus comprising:

• a difference signal generating part for generating a difference signal of each detected signal divided and detected by the optical detecting part;
• a peak detecting part for detecting a maximum value of the output of the difference signal generating part;
• a bottom detecting part for detecting a minimum value of the output of the difference signal generating part;
• a lens position characteristic measuring part for successively generating offset set values for moving the position of the converging part using the moving part at predetermined spatial intervals and obtaining a calculation value based on the detected value of the peak detecting part and the detected value of the bottom detecting part at respective positions to which the converging part has been moved;
• and
• a lens shift adjusting part for searching for the calculation value when a position shift of the converging part with respect to the optical detecting part reaches a minimum and moving the converging part using the moving part based on the offset set value corresponding to the searched calculation value.

A tracking control apparatus for controlling an optical head comprising a converging part for converging and irradiating an optical beam onto an information storage medium having a first address and a second address shifted from an information track toward the inner radius side and outer radius side by approximately ½ track, respectively to perform optical recording and/or reproduction on the information storage medium, an optical detecting part for dividing and detecting reflected light of the optical beam obtained from the information storage medium and a moving part for moving the converging part across the information track, the tracking control apparatus comprising:

• a difference signal generating part for generating a difference signal of each detected signal divided and detected by the optical detecting part;
• a first address amplitude detecting part for detecting an amplitude of the first address section from the output of the difference signal generating part;
• a second address amplitude detecting part for detecting an amplitude of the second address section from the output of the difference signal generating part;
• a lens position characteristic measuring part for successively generating offset set values for moving the position of the converging part using the moving part at predetermined spatial intervals and calculating a difference between the output of the first address amplitude detecting part and the output of the second address amplitude detecting part at their respective positions to which the converging part has been moved;
• and
• a lens shift adjusting part for searching for the output difference which is zero or a value closest to zero and moving the converging part using the moving part based on the offset set value when the output difference becomes zero or reaches a maximum value closest to zero.

A tracking control apparatus for controlling an optical head comprising a converging part for converging and irradiating an optical beam onto an information storage medium having a first areas and a second area exhibiting different reflection characteristics when an optical beam is irradiated to perform optical recording and/or reproduction on the information storage medium, an optical detecting part for dividing and detecting reflected light of the optical beam obtained from the information storage medium and a moving part for moving the converging part across the information track, the tracking control apparatus comprising:

• a difference signal generating part for generating a difference signal of each detected signal divided and detected by the optical detecting part;
• an offset measuring part for measuring an average value during a predetermined period of the difference signal;
• a lens position characteristic measuring part for successively generating offset set values for moving the position of the converging part using the moving part at predetermined spatial intervals and calculating the average value at their respective positions to which the converging part has been moved for the first area and second area of the information storage medium;
• and
• a lens shift adjusting part for searching for the average value when the position shift of the converging part with respect to the optical detecting part reaches a minimum from a relationship between the offset set value obtained in the first area of the information storage medium and the average value and a relationship between the offset set value obtained in the second area and the average value and moving the converging part using the moving part based on the offset set value corresponding to the searched average value.

A tracking control method for controlling an optical head which comprises a converging part for converging and irradiating an optical beam onto an information storage medium having a first address and a second address shifted from an information track toward the inner radius side and outer radius side by approximately ½ track, respectively to perform optical recording and/or reproduction on the information storage medium, an optical detecting part for dividing and detecting reflected light of the optical beam obtained from the information storage medium and a moving part for moving the converging part across the information track, the tracking control method comprising the steps of:

• generating a difference signal of each detected signal divided and detected by the optical detecting part;
• comparing the difference signal with a first level and a second level and generating a first gate and a second gate when the difference signal exceeds the first level and the second level;
• successively generating offset set values for moving the position of the converging part using the moving part at predetermined spatial intervals and determining a measuring count based on the generated first gate and the generated second gate at respective positions to which the converging part has been moved;
• and
• searching for the measuring count when a position shift of the converging part with respect to the optical detecting part reaches a minimum and moving the converging part using the moving part based on the offset set value corresponding to the searched measuring count.

A tracking control method for controlling an optical head which comprises a converging part for converging and irradiating an optical beam onto an information storage medium having a first address and a second address shifted from an information track toward the inner radius side and outer radius side by approximately ½ track, respectively to perform optical recording and/or reproduction on the information storage medium, an optical detecting part for dividing and detecting reflected light of the optical beam obtained from the information storage medium and a moving part for moving the converging part across the information track, the tracking control method comprising the steps of:

• generating a difference signal of each detected signal divided and detected by the optical detecting part;
• detecting a maximum value and a minimum value of the difference signal;
• successively generating offset set values for moving the position of the converging part using the moving part at predetermined spatial intervals and obtaining a calculation value based on the maximum value and the minimum value;
• and
• searching for the calculation value when a position shift of the converging part with respect to the optical detecting part reaches a minimum and moving the converging part using the moving part based on the offset set value corresponding to the searched calculation value.

A tracking control method for controlling an optical head which compares a converging part for converging and irradiating an optical beam onto an information storage medium having a first address and a second address shifted from an information track toward the inner radius side and outer radius side by approximately ½ track, respectively to perform optical recording and/or reproduction on the information storage medium, an optical detecting part for dividing and detecting reflected light of the optical beam obtained from the information storage medium and a moving part for moving the converging part across the information track, the tracking control method comprising the steps of:

• generating a difference signal of each detected signal divided and detected by the optical detecting part;
• detecting an amplitude of the difference signal at the first address section and an amplitude of the difference signal at the second address section;
• successively generating offset set values for moving the position of the converging part using the moving part at predetermined spatial intervals and calculating a difference between the amplitude at first address section and the amplitude at the second address section, at their respective positions to which the converging part has been moved;
• and
• searching for the output difference which is zero or a value closest to zero and moving the converging part using the moving part based on the offset set value when the output difference becomes zero or reaches a maximum value closest to zero.

A tracking control method for controlling an optical head which comprises a converging part for converging and irradiating an optical beam onto an information storage medium having a first areas and a second area exhibiting different reflection characteristics when an optical beam is irradiated to perform optical recording and/or reproduction on the information storage medium, an optical detecting part for dividing and detecting reflected light of the optical beam obtained from the information storage medium and a moving part for moving the converging part across the information track, the tracking control method comprising the steps of:

• generating a difference signal of each detected signal divided and detected by the optical detecting part;
• measuring an average value of the difference signal during a predetermined period;
• successively generating offset set values for moving the position of the converging part using the moving part at predetermined spatial intervals and calculating the average value at their respective positions to which the converging part has been moved for the first area and second area of the information storage medium;
• and
• searching for the average value when the position shift of the converging part with respect to the optical detecting part reaches a minimum from a relationship between the offset set value obtained in the first area of the information storage medium and the average value and a relationship between the offset set value obtained in the second area and the average value and moving the converging part using the moving part based on the offset set value corresponding to the searched average value.