Remote fine positioning mechanism

摘要

A remote fine positioning mechanism of an optical storage device (10) includes a stationary galvanometer-controlled mirror (galvo minor) (49) and an imaging lens (54), the imaging lens positioned to provide an image of the galvo mirror at the front focal point of an objective lens (38) mounted to an optical head assembly (30). The galvo mirror functions as a beam steering element that is rotated about a steering axis to change the angle of incidence of a collimated laser beam (15) with respect to the objective lens during track selection operations. Thus, for rotation of the galvo minor to change the direction of the laser beam, the system operates as though the mirror were physically located at that focal point. To perform the imaging function, the imaging lens decollimates the beam. A collimation-correction lens (44) is therefore provided to ensure, in combination with the imaging lens, that the laser beam remains collimated when it reaches the objective lens.