Multi-beam optical pickup assembly and methods using a compact

Abstract

Apparatus and methods for reading an optical disk are provided that use a compact two-dimensional arrangement of beams, with each beam aligned with a track on an optical disk, to provide a compact assembly having a reduced degree of aberration of the outermost beams while maintaining specified minimum distances between the beams. A preferred embodiment uses a two-dimensional diffractive element to split an illumination beam into a plurality of reading beams aligned with the tracks in a two-dimensional arrangement. In an alternative embodiment, a two-dimensional diffractive element is used to stagger the beams so that some tracks on the disk are skipped, further reducing the area of the beams and increasing the number of tracks that may be read simultaneously.