Osamu Ota

High density digital videodisc using 635 nm laser diode

By developing a high resolution pick-up using a red laser diode with a wavelength of 635 nm and by examining the disc parameters, we have developed a CD-ROM which has a recording density four times that of existing CDs. The track pitch of this CD-ROM is 0.85 /spl mu/m and the recording linear velocity is 0.7 m/s. With these disc parameters, a storage capacity of 2.2 GB was obtained. We recorded digital motion pictures with a data transfer rate of 4 Mbps onto the disc and succeeded in the realization of a high quality digital videodisc with one hour of playback time. >

High Density Muse Videodisc

A MUSE (multiple sub-Nyquist sampling encoding) video disc with 60 min. of playback time per side of CLV disk has been developed. The recording density of the disc is double that of the NTSC video disc. A visible-laser diode with a wavelength of 670 nm and an objective lens with a numerical aperture of 0.6 are used for playing the disc. A fine played-back image with a signal-to-noise ratio of 44 dB was obtained. Two kinds of audio signals are recorded, frequency-division multiplexed PCM (pulse code modulation) and time-division multiplexed PCM. In both systems, a low error rate which presents no practical problems was obtained. >

2.5-inch quadruple-density CD-ROM using visible laser diode

We have achieved a 2.5 inch (64 mm) quadruple density CD-ROM by developing a high resolution pick-up with our newly-developed visible laser diode whose wavelength is 635 nm, and also developing a disk cutting machine using a Kr ion laser with a wavelength of 407 nm.

High-density HDVD system using visible laser diode

We have presented a high density MUSE videodisc with 60 minutes of playback time per side. It has been developed by doubling the disc recording density. We have continued examining the system mainly the optical pickup and the signal parameters and we determined the newly specifications. To reduce the influence of uneven thickness and tilt of disc we changed an N. A. of the objective lens to 0. 55 and to make the optical pickup smaller we employed a small packaged (

High-density optical MUSE disk

5. 6mm) visible laser diode. The visible laser diode has a low aspect ratio ( 0 32 0 11 0 / 0 2. 9 ). And to make the SN ratio of the playback signal higher we widened the FM deviation and lowered the FM carrier frequency. Under new conditions we made PMMA replica discs. As a result a high quality played back image without crosstalk noise was obtaind. 1.

3-d model providing device

A high-definition videodisc with 60 minutes of playback time per side has been developed by doubling the disc recording density and using an optical pick-up employing laser diode with a wavelength of 670 nm. MUSE (Multiple Sub-Nyquist Sampling Encoding) video signal and two kinds of PCM sounds are recorded. In the disc with a linear velocity of 14 m/s and a track pitch of 1.12 micrometers , a playback image without cross-talk noise was obtained. In this paper, the development of a disc recording and playback system, and the optimization of recording conditions, which were carried out to achieve 60 minutes of playback time per side, are described.