Original Publication Date: 1989-Oct-01
Included in the Prior Art Database: 2005-Jan-29
Astigmatism is adjusted out of the optical head of an optical disk drive data storage device by slightly defocusing the head's collimator lens. This correction is possible due to the fact that when a non- collimated light beam is passed through an anamorphic beam expander, a change in astigmatism is introduced into the beam. Therefore, a single correct position can be found for the collimator lens which is down stream of the beam expander. The collimator is moved axially to correct for the beam's astigmatism. This adjustment can be automated and controlled by a computer.