System and method for aligning components of optical head

Abstract

Extremely small optical heads are being developed for use in optical storage devices. The heads typically include a light source, a lens and a photodetector array. The beam of light generated by the light source must be aligned precisely with central axis of the lens and with the photodetector array. Because the heads are so small, their components are fixed permanently together; no adjustments are possible after assembly. A system of this invention includes a rotational stage, a pair of X-translation stages, and a pair Y-translation stages. The stages are mounted in a mechanical path between first and second holding devices. One component of the head, which would typically include the light source, is held in the first holding device. Another component, which would typically include the lens, is held in the second holding device. The stages are adjusted until the light beam exits the first component on an axis that coincides with the center of rotation of the rotational stage. The position of the second component is adjusted until the light beam coincides with the axis of the lens. The first component is then rotated until the light beam strikes the photodetector array at an optimal position. The optimal position can be obtained by directing the light beam at a media driven by a tracking actuator and optimizing the output signal from the head.