OPTICAL RECORDING AND REPRODUCING DEVICE

摘要

PURPOSE:To obtain a small-sized and efficient optical recording and reproducing device by providing an optical element consisting of a pair of convex lenses which receive the light reflected by a recording medium and passed through an objective lens and make said light incident to two sets of photodetectors. CONSTITUTION:Light from a light source 1 is converted to parallel light and is thereafter made incident through a half mirror 2 and an objective lens 3 to a recording body 4. The reflected light thereof is made incident through the lens 3 and the mirror 2 to an optical element 12. The element 12 is formed into the shape in which the optional part of the convex lens without contg. the optical axis is cut on the plane parallel with the optical axis of said lens and the cut faces are adhered or fixed to each other so as to make the optical axes of the convex lenses parallel with each other. Said element has thus the two optical axes. The light transmitted through the element 12 is therefore converged to two half spots, the one of which is made incident to a bisected photodetector 7 and a focus error signal is obtd. from a differential amplifier 8. The other is made incident to a photodetector 10 and an information signal and a tracking error signal are obtd. from an amplifier 11.