Optical information recording medium and a reproducing apparatus for the recording medium

摘要

An optical information recording medium, to and from which information can be recorded or reproduced at a high density, uses more number of kinds of pits than those of a conventional optical disc. A reproducing apparatus for such a medium also is devised. Information is recorded onto the recording medium by using a plurality of pit lengths which are obtained by dividing a whole frequency band below a cut-off frequency of MTF characteristic of a reproducing system into a plurality of bands in correspondence to the band characteristic and by allocating a plurality of spatial frequencies to the divided bands. The reproducing apparatus of the invention comprises an optical pickup to read out the recording information from the optical recording medium and signal demodulating means for demodulating the original data from the pulse width and amplitude value of the reproduction signal which is supplied from the optical pickup, wherein the optical pickup is designed to have an MTF characteristic such as to have one or a plurality of peaks at certain frequency positions.