High density optical disc and optical disc player
AssigneeSanyo Electric Co., Ltd.
InventorsYoichi Tsuchiya, Hitoshi Terasaki, Shuichi Ichiura, Toshio Ito, Yasuyuki Kano, Yoshimoto Yamaguchi, Seizo Kato, Osamu Ota
Life of this patent
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Abstract
An optical disc having a track pitch of 0.85 .mu.m, a shortest pit length of 0.49 .mu.m, a pit depth of 100 nm, and a pit width of 0.35 .mu.m is rotated at a linear velocity of 2.4-2.8 m/s such that the same is optically reproduced by a laser beam having a wavelength of 635 nm which is converged to a spot size of 0.9 .mu.m by an objective lens having a numerical aperture of 0.6, Accordingly, data is read from the optical disc at a transfer rate of 5.6 Mbps.
Claims15
An optical disc player for reproducing an information signal from one of an optical disc format and an optical disc having a track pitch of 0.7-0.85 .mu.m, a pit width of 0.20-0.35 .mu.m, and a shortest pit length of 0.42-0.49 .mu.m, comprising:
- a semiconductor laser having a wavelength of 590-770 nm;
- irradiating means for irradiating a beam from said semiconductor laser onto said optical disc with a spot size of 0.85-0.95 .mu.m;
- detecting means for detecting reflected light from said optical disc;
- and
- photo-electric conversion means for converting said detected reflected light into an electric signal and outputting said electrical signal as said information signal.
An optical disc player for reproducing an information signal from one of optical disc format and an optical disc having a track pitch of 0.8-1.00 .mu.m, a pit width of 0.20-0.35 .mu.m, and a shortest pit length of 0.42-0.49 .mu.m, comprising:
- a semiconductor laser having a wavelength of 590-770 nm;
- an objective lens having a numerical aperture of 0.5-0.6 for irradiating a beam from said semiconductor laser onto said optical disc;
- and
- detecting means for detecting reflected light from said optical disc and photo-electric conversion means for converting said detected reflected light into an electrical signal and outputting said electrical signal as said information signal.
An optical disc player for reproducing an information signal from one of an optical disc format and an optical disc having a track pitch of 0.7-0.85 .mu.m, and a shortest pit length of 0.42-0.49 .mu.m, comprising:
- a semiconductor laser having a wavelength of 590-770 nm;
- an objective lens having a numerical aperture of 0.5-0.6 for irradiating a beam from said semiconductor laser onto said optical disc;
- detecting means for detecting reflected light from said optical disc and photo-electric conversion means for converting said detected reflected light into an electrical signal and outputting said electrical signal as said information signal.
An optical disc player for reproducing an information signal from one of an optical disc format and an optical disc having a track pitch of 0.8-1.00 .mu.m, and a shortest pit length of 0.42-0.49 .mu.m, comprising:
- a semiconductor laser having a wavelength of 590-770 nm;
- an objective lens having a numerical aperture of 0.5-0.6 for irradiating a beam from said semiconductor laser onto said optical disc;
- and
- detecting means for detecting reflected light from said optical disc and photo-electric conversion means for converting said detected reflected light into an electrical signal and outputting said electrical signal as said information signal.
Dependencies are inferred from the claim text.