OPTICAL INFORMATION REPRODUCING DEVICE

摘要

PURPOSE:To widen a focus error detective range in an optical information reproducing device. CONSTITUTION:Auxiliary light sources 5' and 5'' are contained beside a light source 5 and these auxiliary light sources are displaced to an opposite side to the light source 5 to a main optical system light axis, and further symmetrically shifted with the main optical system light axis in the direction perpendicular to the main optical system light axis. Auxiliary beams outgoing from these auxiliary light sources are aperture-limited by apertures 19, 19' for decreasing a focusing degree on a recording medium than a reading beam 10. Thus, though the focusing degree of the reading beam 10 is increased, the optical system with a wide focus error detection range is constituted.