Flat-Field Imaging for Optical Data Storage Using Symmetrical Optical Systems and Curved Laser Arrays
Original Publication Date: 1989-May-01
Included in the Prior Art Database: 2005-Jan-28
A technique for flat-field imaging of a laser array onto an optical recording layer is disclosed that uses a symmetrical optical imaging system and a curved laser-diode array to eliminate third-order coma and field curvature and minimize astigmatism. The number of beams that can be imaged with diffraction limited performance onto a plane recording layer is limited by coma, field curvature, and astigmatism in the optical system. The figure shows the write path of an optical storage drive where the off-axis aberrations are minimized by the use of a symmetrical optical system and a laser- source array with a curved datum. A symmetrical optical system has complete mechanical symmetry about its aperture stop. In this type of optical system the third- order coma, third-order distortion, and transverse chromatic aberration are zero.