| 摘要 |
PROBLEM TO BE SOLVED: To only externally attach a universal IC having no correcting means for tracking error signals and to make it possible to easily adjust the balance of the tracking error signals. SOLUTION: This element has an adder means 112 for obtaining the signals α, β relating to the tracking error of a push-pull system from the signals relating to the respective photodetectors of a first photodetector group PD1 and second photodetector group PD2 through a current-voltage conversion means 110. The element contains the correction means 120 for correcting the signals relating to the tracking error of the push-pull system and adding the DC offset component of the signals relating to the tracking error. |
