Sony Corporation

Hideo Kawachi

Tadao Yoshida

Jun Nakano

Tetsuhiro Sakamoto

Toshiyuki Arai

Chiaki Nonaka

Teruaki Higashihara

Takayuki Asahina

Katsuichi Sakurai

Toshiharu Kondo

Etsuo Shibasaki

Yoshitake Yanagisawa

Koji Ishiwata

Makoto Tsukahara

Inho Cho

An information signal area on an information signal recording surface is provided as pits on a mirror in accordance with modulated information data, and is covered with a metal alloy reflective film. Sections that do not include pits corresponding to the information data are provided in the information signal area, and portions of the metal alloy reflective film on the sections are formed as perforated marks corresponding to the information data. In this case, the reproduction signal amplification level of a prepit signal and the reproduction signal amplitude level of a perforated mark signal can be obtained as substantially equal values by adjusting the depth and width of pits and/or adjusting the width and length of perforated marks. Hence, waveform distortion due to a waveform equalization circuit and variations in binary signals due to displacement of the slice level are reduced so that signals can be stably and reliably detected with the same reading apparatus.

Method for manufacturing read-only optical disc medium and read-only optical disc medium

An optical disk read only memory having an information recording surface with a concave-convex pattern formed on the basis of a first signal and a reflective film covering the surface. The disc medium includes: an additional information recording section formed on a recording track of a first data string; and a second data string including a mark of removing or reducing the reflective film. The modulation methods of the first and the second data strings are identical, and Lh(n)&#x3e;Lp(n) and Wh(n)&#x3e;(Wp(n)+Wp(n))/2 are satisfied, where a reference clock cycle is T, a data length is nT, a length and a width of the mark are Lh(n) and Wh(n), a length and a width of a base of the pit are Lp(n), and Wp(n), a length and a width of a top face of the pit is Lp(n) exceeding Lp(n), and Wp(n) exceeding Wp(n).

Optical disk read only memory

In a reproducing system, a reproducing start position of recording information is set in a first reproducing device reproducible in a second reproducing device. The reproducing start position set in the first reproducing device is stored in a detachable external storage medium. The external storage medium is detached from the first reproducing device, attached to a second reproducing device, and the reproducing start position stored in the external storage medium is read into the second reproducing device. Thus the reproducing start position set by the first reproducing device will be reproduced in the second reproducing device to control a location of selection, such as musical numbers.

Reproducing system with detachable storage medium for storing selected

A disk player for use of playback of both of the single body of a digital optical disk and another digital optical disk encased in a cartridge by a single player. The disk player comprises a disk tray which is mounted on a main chassis and adapted to make its reciprocating movement in the fore-and-aft direction of the player to carry the single body of the disk to a predetermined position in the player. A cartridge carrier is mounted on a sub-chassis connected to and located above the main chassis and makes its reciprocating movement in the fore-and-aft direction to carry the cartridge encasing therein the disk to another predetermined position in the player. A mechanical chassis is tiltably connected to and located below the main chassis and movable upwardly and downwardly. A turntable is rotatably mounted on the mechanical chassis and driven by a motor supported to the mechanical chassis. Either one of the disks carried at the predetermined position is mounted on the turntable to be played back. An optical pickup is movably mounted on the mechanical chassis to pick a digital optical signal from the surface of the disk on the turntable.

Apparatus for carrying out recording and/or reproducing signals for

A disc player is shown which can play both a naked disc and a disc encased in a cartridge. A disc tray is movable on a single horizontal way to take at least first, second and third positions which are respectively the position for receiving or ejecting the naked disc, the position for practically playing the naked disc and the position which is distant from the second and third positions. When playing of the cartridge is intended, the disc tray is moved to the third position to permit the cartridge to take a loaded position at which the cartridge is practically played.

Disc player for playing both naked disc and cartridge-encased disc

In an apparatus for reproducing digitized signals recorded in successive, substantially circular tracks on a rotated disc by means of a pickup of the optical type which, in a normal scanning state, scans the tracks in succession; a first or prepare-to-play command signal causes the pickup to reproduce the digitized signals for a predetermined interval corresponding to more than one of the tracks on the disc starting from a desired position on such one track and the digitized signals reproduced in that predetermined interval are stored, desirably in a random access memory (RAM), whereupon a standby state of the pickup is established in which the pickup traces a closed loop on the rotated disc within a range corresponding to the previously mentioned predetermined interval. Upon reception of a second or play command signal, the pickup is released from its standby state at the completion of the tracing of the closed loop during which the play command signal occurred and the normal scanning state of the pickup is reestablished. Further, in response to the second or play command signal, the stored digitized signals are read out from the RAM and transmitted, starting with the signals corresponding to the desired position irrespective of the rotational position of the disc at the time of the play command signal, and the digitized signals reproduced by the pickup on the reestablishment of its normal scanning state and, more particularly, commencing with the digitized signals following the predetermined interval, are sequentially stored in the RAM and then sequentially read out and transmitted therefrom.

Disc reproducing apparatus

An apparatus for playing information recorded on a disc in substantially circular tracks on the latter includes a device for rotating the disc; a pickup for reproducing the information recorded on the disc; a tracking control circuit for adjusting the tracking position of the pickup in forward and reverse transverse directions with respect to the tracks; and a circuit operative through the tracking control circuit for selectively establishing a slow-playback mode and a reverse slow-playback mode in each of which, after the pickup reproduces a respective first predetermined number of the tracks while moving in the forward transverse direction, the tracking position of the pickup is moved in the reverse transverse direction a respective second predetermined integral number of tracks, the second predetermined number of tracks being less than twice the first predetermined number of tracks.

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Tokyo, Japan

Hideo Kawachi