Optical record medium reading apparatus having a de-focussed light beam projected on an optical record medium

摘要

An apparatus for reading information out of an optical record medium including a semiconductor laser diode for emitting a laser beam, a collimator lens, a beam splitter, an objective lens, converging lens and a photodetector. The laser beam emitted from the laser diode is made incident upon the optical record medium via the collimator lens, beam splitter and objective lens, and a light flux reflected by the optical record medium is made incident upon the photodetector via the objective lens, beam splitter and converging lens. The laser diode and collimator lens are arranged such that the laser beam is projected upon the optical record medium in a de-focused condition, while the objective lens is in- focused on the optical record medium.