Pioneer Corporation

Pioneer Electronic Corporation

Pioneer Video Corporation

Other

Toshihiko Takishita

Eiji Muramatsu

Shoji Taniguchi

Masahiro Kato

Seiro Oshima

Shigenori Murakami

Kenji Suzuki

Atsushi Yamaguchi

Kunihiko Horikawa

Akiyoshi Inoue

Minemasa Ohta

Takao Tagiri

Hiroyuki Takahashi

Satoru Fukuoka

Makoto Matsukawa

Kazuo Kuroda

Yoshio Sasaki

Kiyohide Ogasawara

Hiroshi Ito

Tatsuhiro Yone

Haruyasu Sakata

Masataka Yamaguchi

Hiroshi Nishiwaki

Shinichi Hanzawa

Miki Kusama

Hirokazu Hashikawa

Tsuyoshi Hayashi

Ayumi Mitsumori

Atsushi Kondo

Tuyoshi Hayashi

An information recording medium comprising a substrate (), a recording layer () formed on the substrate in order to record information, a color filter () formed on the substrate, and a thermal reflectance variation layer () formed on the substrate in order to vary light reflectance by heat incident to irradiation of light and to reflect visible light entering from one side of the substrate through a color filter. High precision color writing or color label writing can be carried out on an information recording medium such as DVD and BD where a label can be written on the surface by irradiating light.

Information recording medium

An optical-recording medium is provided with at least a first recording layer for recording information optically; and a second recording layer for recording information optically by a light beam that passes through said first recording layer; wherein the track pitch of a recording track that is formed on said second recording layer is narrower than the track pitch of a recording track that is formed on said first recording layer.

Optical recording medium, information recording apparatus and information reproduction apparatus

A recording layer close to a disc surface is divided into at least two recording areas, a main information recording area DA and an auxiliary information area (BCA) DC. Grooves are formed in the main information recording area DA. Marks M are formed in barcode form representing identifying information in the auxiliary information recording area (BCA) DC. Track grooves Gor prepits are formed in the recording layer of the auxiliary information recording area (BCA) DC and have a depth smaller than that of the groove formed in the main information recording area DA.

Optical disc

A groove track and a land track are alternately and spirally formed on an information recording medium. On the land track neighboring the groove track, pre-information indicating position information of a track on a disc is formed as a prepit. On the information recording medium, an embossed area is formed so that information about a copyright and for preventing an illegal copy cannot be rewritten. In the embossed area, an embossed configuration including a pit and a space of predetermined depths is formed. The prepit in the embossed area is formed so that the prepit has an optimized configuration according to a pit length and a space length in the embossed area which the prepit neighbors. Consequently, interference between the embossed configuration and the prepit can be prevented even in a case that the prepit is formed in addition to the embossed configuration in the embossed area.

A rewritable type optical disc includes recording tracks formed with break portions; and recording marks corresponding to predetermined data and formed on the recording tracks. The recording marks are formed over the break portions on the recording tracks. If the predetermined data, such as control data, recorded as the recording mark is illegally altered, the position of the recording marks are changed and some break portions are not covered by the recording marks. Since the return light level of the break portion, which is not covered by the recording mark, is different from the return light level of the break portion covered by the recording mark, such illegal alteration of the predetermined data such as the control data may be detected.

Rewritable type optical disc including recording marks over break portions of recording tracks, manufacturing method and manufacturing system therefor

An optical recording medium is provided which comprises: a substrate including concentrically or spirally formed grooves each having a V-shaped cross section; a first dielectric layer formed on the substrate; a phase-change recording layer formed on the first dielectric layer; a second dielectric layer formed on the phase-change recording layer; and a metallic reflecting layer formed on the second dielectric layer. In particular, the optical recording medium is so formed that an objective lens having an aperture number of 0.55-0.70 can be used and a laser beam having a wavelength of 600-700 nm and passing through the objective lens is passed through the substrate and then converged on the recording layer, thereby recording or reproducing information on the recording layer in areas corresponding to the grooves. Specifically, the optical recording medium further comprises a third dielectric layer consisting of a nitride, the third dielectric layer being disposed between the first dielectric layer and the phase-change recording layer. In this way, it is possible to prevent a deterioration possibly caused due to a heat in the boundary between the first dielectric layer and the second dielectric layer, thereby greatly increasing the number of possible times for over-write recording.

Optical recording medium

An optical recording medium which can produce a read signal free from waveform distortion during reproduction of information. The optical recording medium comprises groove information tracks on which information pits carrying information data is to be formed, and prepit tracks provided with a plurality of previously formed land prepits connected to the groove information tracks. The groove information tracks and the prepit tracks are arranged in alternation. The groove information track has a track width smaller in at least a part of each of sections in which the land prepit exists than in sections in which no land prepit exists.

Optical recording medium having pre-formed land-prepits and method for producing same

An optical recording medium is designed to generate a read signal free from waveform distortion during reproduction of information. The optical recording medium is formed with information tracks on which data pits carrying information data is to be formed, and prepit tracks previously formed with a plurality of prepits. Each of the information tracks and each of the prepit tracks are positioned adjacent to each other, and each of the prepits is formed to be spaced apart from adjacent information tracks in at least its bottom part.

An optical recording medium has a substrate having an annular grooves, a recording layer including an organic coloring matter and formed on the substrate, and a metallic reflection layer. The recording layer has a thickness so as to have an absorbance between 0.65 and 0.75. Information is recorded in the recording layer by a laser beam having a wavelength between 600 and 700 nm, using an objective lens having a numerical aperture between 0.55 and 0.70.

Two-disc laminated optical recording medium

A recordable optical disc on which information is recorded by applying a light beam on the surface thereof, includes: a first recording area on which information is recorded and reproduced while the disc is rotated at a first linear velocity; and a second recording area on which information is recorded and reproduced while the disc is rotated at a second linear velocity. The first recording area and the second recording area include guide grooves having wobble frequency lower than frequency band of EFM signal.

Optical disk having first and second recording areas with wobble

An apparatus for recording information on a recordable optical disc by applying a light beam on the surface thereof, the disc includes a first recording area on which information is recorded and reproduced while the disc is rotated at a first linear velocity; and a second recording area on which information is recorded and reproduced while the disc is rotated at a second linear velocity. The first recording area includes a test recording area. The apparatus includes recording power determining unit for determining first optimum recording power for recording information on the first area by a test recording utilizing the test recording area, and for determining second optimum recording power for recording information on the second area by multiplying the first optimum recording power by a predetermined constant.

Apparatus for and method for determining optimum power for recording

An optical information recording medium recordable of the analogue NTSC color video signal under the conditions of a high S/N ratio and a low jitter, and capable of being played by a commercially available LD player. The medium comprises: a transparent substrate on which pre-grooves are formed with a depth of 1450-2050 angstroms; an optical absorbing layer with an absorbance of 0.7-0.9 made of palladium phthalocyanine dye formed on the substrate, the absorbing layer having pits each having a changed reflectivity being duty-cycle modulated in response to a limited waveform which is formed through the steps of: adding at least one of a second FM carrier and a third pulse carrier to a first FM carrier having a first center frequency and a first frequency band, the second FM carrier having a second center frequency lower than the first center frequency and a second frequency band spaced from the first frequency band, the third pulse carrier having a pulse-repetition frequency lower than the second center frequency and a third frequency band spaced from the second frequency band, to form a frequency-division multiplex signal; and symmetrically clipping the multiplex signal to form the limited waveform; and reflecting layer formed on the optical absorbing layer.

Information recording medium and method for recording information to the

An optical disk of the type including guide grooves is improved by regulating the width of the grooves, and thus the width of the adjacent land portion, in accordance with the type of information recorded at that part of the land.

Optical disk having narrow and wide guide grooves

In an optical disk manufacturing method in which a first photo resist layer, an intermediate resin layer, and a second photo resist layer are formed on a substrate in the stated order, a resin solution which is unsoluble in organic solvent is applied to the first photo resist layer, heated, and hardened to form the intermediate resin layer. Thereby the use of a large, expensive device such as a vacuum deposition device or sputting device is eliminated.

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Yamanashi, Japan

Toshihiko Takishita