ABERRATION CORRECTOR AND OPTICAL PICKUP DEVICE USING THE SAME

摘要

PROBLEM TO BE SOLVED: To prevent the deflection of irradiation optical axis and to satisfactorily remove a time fluctuation noise component by forming the optical path length of a light beam passing through a pair of light transmission substrates so that a phase difference maintains the travel direction of the light beam while a phase difference is given to the light transmission light beam. SOLUTION: This aberration correction 100 consisting of a first correction board 101 and a second correction board 102 is arranged between a collimator lens and an objective lens in an optical path from a semiconductor laser to an optical disk 5 or an optical path from the optical disk 5 to a photodetector, for example. Curved surfaces 101a and 102a being complementary aspheric surfaces which are detached and face each other give a phase difference by permitting the optical path length of the transmission light beam to change with the movement of one of the two correction boards so as to minimize the frame aberration of a tangent direction, which is given to the light beam passing through the transparent substrate of the optical disk. The phase difference is formed to maintain the travel direction of the light beam.