Sony Corporation

Katsuhiko Ohtomo

Sohmei Endoh

Hiroshi Nakayama

Hiroyuki Takemoto

Masaki Kagawa

Hiroshi Nomura

Tadao Suzuki

Masayoshi Kanno

Masataka Shinoda

Tomiji Tanaka

Mitsuo Arima

Makoto Watanabe

Takahiro Igari

Ikuhiro Hideta

Manabu Iwai

Yuko Asano

Binary information previously recorded in an innermost rim side area is enabled to be stably reproduced. A record medium is formed by sequentially laminating a first information layer, an intermediate layer, a second information layer, and a cover layeronto a substrate. First grooves are previously formed in the innermost rim area of the substrate. Second grooves are previously formed in an area where data is recorded. The first grooves are set to be shallower and narrower than the second grooves. Thus, such a situation that a BCA signal is modulated by diffraction due to the grooves can be reduced.

Record medium, its manufacturing method, mother disc for record medium, and its manufacturing method

The stable reproduction of wobble signal without generating beats despite of an improvement in recording density by narrowing a track pitch is realized. Data by magnetooptical recording is recorded on wobbling grooves and lands between adjacent wobbling grooves. The wobbling grooves are provided to wobble both sides of the grooves in different amplitudes. Further, both the sides wobbled in different amplitudes are wobbled in phase in the track direction. These different amplitudes of both sides are preferably set to 3.3 to 40%.

Optical recording medium with grooves, optical recording medium master with grooves, apparatus for manufacturing optical recording medium master with grooves, and optical recording/reproducing apparatus

In an optical recording medium having a writable area in which grooves are formed along recording tracks and a read-only area in which pits are formed along the recording tracks, sufficient levels of signals required for data write and read can be assured even with the track pitch reduced for a higher recording density. Assuming that the refractive index of a medium provided extending from a light-incident surface to a surface in which the grooves and pits are formed is n and the wavelength of a light used for data write and read is &lgr;, the grooves and pits has a width within a range of &lgr;/7.5 n to &lgr;/6. On the assumption that the width of each of the grooves formed in the writable area is Wg and the pitch between the recording tracks in the writable area is Tp , Wg/Tp is within a range of 18.4% to 31.1%. When it is assumed that the width of each of the pitches formed in the read-only area is Wp and the pitch between the recording tracks in the read-only area is Tp , Wp/Tp is within a range of 35.7% to 44.3%.

Optical recording medium capable of assuring sufficient levels of signals required for reading/writing data, and stamper for manufacture of the same

In an optical recording medium having formed along recording tracks thereon pits indicative of information signal, a ratio Pw/Tp where Pw is the width of the pit and Tp is the pitch of the tracks is within a range of 0.4 to 0.55. The push-pull method or differential push-pull method is adopted for tracking servo control of the optical recording medium.

High density recording medium with pit width to track pitch ratio in the range of 0.4 to 0.55 for push-pull tracking servo control

Even if grooves are, in order to improve productivity, omitted from an optical recording medium having pits indicating information signals formed in at least a portion of recording tracks of the optical recording medium, signals having satisfactorily high levels required to perform tracking control are attempted to be obtained. The number of regions of the recording tracks in which the pits are formed is made to be larger than the number of regions in which no pit is formed. Specifically, since '0' has higher appearance probability than '1' in a case of a binary information signal consisting of '0' and '1', pits are formed at positions corresponding to '0' of the information signal.

Optical recording medium having a specified range of pit widths and pit

An optical recording medium capable of being reproduced by a conventional drive device which meets an optical disk having grooves and no groove in an area in which pits are formed. In the optical recording medium having pits 1 showing information signals in the shape of protruding and recessed parts, it is assumed that the depth t1 of the above mentioned pits t2 of the pits 1 is located within a range of 0.3 to 0.6 .mu.m. Herein, n designates the refractive index of the base of the optical recording medium and designates the wavelength of the light used for reproduction.

Base for optical recording medium and stamper for manufacturing base of

Method of measuring a deviation between a centerline between grooves and

Optical disc having buffering areas capable of storing a pattern for

An editing can be made in real time while data is being input. A recording and reproducing method comprises a first processing step for reading out first information (D1) on a recording medium (D) and storing the first information (D1) thus read out in a storage memory (18), a second processing step for writing third information (D3), which results from synthesizing the first information (D1) read out from the recording medium (D) and second information (D2) input from the outside, in an output memory (19), and a third processing step for reading third information (D3) of a predetermined capacity from the output memory (19) and recording the third information (D3) thus read out on the recording medium (D), wherein after a first operation cycle composed of the first processing step, the second processing step and a loop processing operation for repeating a composite operation of the second and third processing steps until the storage capacity of the storage memory (18) reaches a predetermined capacity is carried out once, a second operation cycle composed of the first processing step and a loop processing operation for repeating a composite operation of the second and third processing steps until the storage capacity of the storage memory (18) reaches a predetermined capacity is repeated until the reading is finished.

Recording and reproducing apparatus and recording and reproducing method

A rotation of an optical disk can be controlled with high accuracy to thereby reduce a rotational jitter, whereby a buffer area between sectors can be reduced to increase a storage capacity of the optical disk. In an optical disk in which a track (3) defined by a groove (2) is formed on a rotational base plate and a recording pit (4) corresponding to information is formed on the track (3) in a multi-channel fashion, the groove (2) is formed as a pattern which is fine wobbled in the optical disk radiation direction shown by an arrow (r) and address information (9) of the track (3) is provided in the groove (2).

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Miyagi, Japan

Katsuhiko Ohtomo