Patent ID: 6944111
Filing Date: 2005-09-13
Classification: G11B

Abstract:
1. An information reading and recording apparatus comprising: a semiconductor laser; a collimating lens adapted to converge a divergence angle of a laser beam emitted from the semiconductor laser; two objective lenses having respective numeral apertures suitable for reading and recording two types of recording media each having a recording density different from other, and adapted to converge the laser beam onto respective recording media; a super-resolution cut-off filter comprising a light-transmissible substrate, having an annular reflecting means at a center portion of the substrate, and disposed immediately before one objective lens of the two corresponding to one recording medium of the two types with a higher recording density; and a photo-detector adapted to detect a reflected laser beam from any one of the two types of recording media, whereby information is read and recorded compatibly in the two types of recording media.