Optical device for access to a track carried by a data carrier and optical memory system incorporating such a device

摘要

Optical device for giving access to a track carried on a moving data carrier incorporating a moving element comprising a galvanometric mirror and a focusing objective movable relative to the data carrier and a fixed light energy source incorporating at least one laser emitter. Magnifying optical means of the afocal type are also inserted between the moving element and the light energy source. The magnification is sufficient to ensure that the beam emerging from the optical means completely covers the entrance pupil of the objective. As a result of this arrangement, the beam of light reaching the moving element remains a beam of parallel rays, no matter what the position of said element relative to the light energy source.