OPTICAL SPOT GENERATION DEVICE FOR RECORDING MEDIUM

摘要

The size of a collimator lens (28) is reduced to make compact an optical pickup device (10). The collimator lens (28) has a size which allows an object lens to receive collimated light on the whole surface thereof. Although the objective lens (30) is displaced in a radial direction R (perpendicular to a track) by track servo control, it is not displaced in a tangential direction T (track direction). Therefore, the length of the collimator lens in the tangential direction T can be made shorter than that in the radial direction R.