Tdk Corporation

Adk Corporation

Hiroyuki Arioka

Masaharu Nishimatsu

Toshiaki Ide

Yuichi Kubota

Takashi Horai

Syuji Tsukamoto

Suguru Takayama

Junji Tominaga

Narutoshi Fukuzawa

Toshiki Aoi

Hideki Ishizaki

Kazuki Suzawa

Akio Ogawa

Tomoki Ushida

Shirou Ootsuki

Motohiro Inoue

Hiroshi Take

Shigeru Shimada

Atsuko Motai

Yoshiaki Saito

Koji Kobayashi

Kiyoshi Noguchi

Tsuyoshi Komaki

Keiji Koga

Mamoru Usami

Susumu Haratani

Toshihiko Ishida

Tokuhiko Handa

Akio Watanabe

Kenji Uchiyama

Shuji Tsukamoto

Hideki Sunohara

Hideki Dohi

Tetuji Takamizawa

Koji Yasukawa

Yasukawa Koji

Megumi Yoshimura

Masharu Nishimatsu

A multi-level optical recording medium according to the present invention is a multi-level optical recording medium () which is capable of recording record data according to multi-level recording that defines light reflection ratios of recording portions () into multiple levels by switching the irradiation amount of a recording laser beam between multiple levels, wherein light reflection ratio information enabling identification of a light reflection ratio dynamic range within which respective light reflection ratios of the recording portions () should be included is readably recorded. Due to this construction, when record data are recorded, it is only required to record the record data such that the respective light reflection ratios of the recording portions () are included within the light reflection ratio dynamic range identified from the light reflection ratio information, and it is unnecessary to perform the operation of checking the characteristics of the multi-level optical recording medium () prior to recording the record data. Therefore, it is possible to record the record data promptly and easily without wastefully using a data-recording area.

Multi-level optical recording medium, multi-level recording method, and multi-level reproduction method

It is an object of the present invention to provide a multilevel optical recording medium in which influence of variation in characteristics of a recording layer in a plane of the recording layer on reproduced data can be corrected The multilevel optical recording medium according to the present invention includes at least a recording layerand is constituted so that data can be recorded therein in a multilevel manner by controlling a state of the recording layeramong multiple stages and the multilevel optical recording medium according to the present invention is characterized in that a plurality of calibration signals are stored in the recording layerAccording to the thus constituted multilevel optical recording medium, since an optical data recording and reproducing apparatus can detect and correct for the variation in characteristics of the recording layerin the plane thereof, even in the case where variation in characteristics of the recording layerin the plane thereof is present, data recorded in the multilevel optical recording medium in a multilevel manner can be read in a desired manner.

Multilevel optical recording medium with calibration signals

A reproduction method for a multi-level optical recording medium according to the present invention rotates an optical recording medium, on which recording data has been recorded according to a multi-level recording method which sets several levels for light reflectivity of virtual recording cells, emits a reproduction laser beam towards the optical recording medium, and reproduces the recording data based on an electric signal generated in accordance with a received level of reflected light, the method setting the emission power of the reproduction laser beam in a range of 1.0 mW to 2.5 mW inclusive when the optical recording medium is rotated at a linear velocity in a range of 9 m/s to 25 m/s inclusive. By doing so, it is possible to improve the read accuracy for recording data while suppressing the reproduction deterioration of the optical recording medium to a level where deterioration effectively does not occur.

Multi-level optical recording medium reproducing method and reproducing device

On a recording layer () of a disc-shaped optical recording medium (), a plurality of virtual recording cells () are assumed contiguously in a spiral or concentric fashion in a groove (). The irradiation time of the laser beam is modulated in five stages or more for each of the virtual recording cells () in response to information to be recorded, thereby forming recording marks (A toG) of different sizes in five stages or more. The optical reflectivity of the virtual recording cell () is modulated in multi-stages to thereby vary the reflection level of a reading laser beam for reading operations in five stages or more. The length of the virtual recording cells () in the rotational direction of the disc is set to be equal to that of an arc having the same center angle with respect to the center of the disc.

Optical recording medium and optical recording method by irradiation

An optical recording medium can be recorded at a high linear velocity of at least 10 m/s while maintaining an excellent light stability and favorable reflectance. A recording medium is constructed of a recording layer on a substrate, the recording layer including a first dye with a maximum absorption wavelength in a thin-film state of 450 nm to 620 nm inclusive as a first dye and being formed so as to include a second dye with an extinction coefficient of at least 0.5 for a recording wavelength. In this case, it is preferable for the second dye to have a maximum absorption wavelength of 620 nm to 750 nm inclusive in a thin-film state.

Optical recording medium

Virtual recording cells are assumed within a groove on a recording layer of an optical recording medium. Recording marks with five or more different sizes are formed on each of the virtual recording cells by means of modulating the irradiation time of the laser beam in five levels or more in correspondence to the information to be recorded. The reflectance of the virtual recording cells modulates in many levels and the reflection level of the readout laser beam during regeneration is modulated in five levels or more.

Optical recording medium and optical recording method

The invention provides an optical recording medium having excellent weatherability and a process for producing the same. The optical recording medium is provided with an organic dye layer, a reflecting layer and a protective layer in this order on a light-transmittable substrate. The organic dye layer contains an organic solvent in an amount of 2% to 15% by weight based on the organic dye. A solution, prepared by dissolving an organic dye in an organic solvent, is applied onto the light-transmittable substrate by a spin coating method to form an organic dye layer. A reflecting layer is formed on the organic dye layer without performing a drying treatment of the organic solvent in the organic dye layer, followed by forming the protective layer on the reflecting layer. The result is an optical recording medium containing an organic solvent in an organic dye layer in an amount of 2% to 15% by weight based on an organic dye.

Process for producing optical recording medium and optical recording medium

An optical recording medium is provided with a recording layer and a reflecting film on an optically transparent substrate. The principal component of the recording layer is a dye. Virtual recording cells are assumed within grooves on the recording layer and recording marks with five different levels or more of increasing size are formed on each of the virtual recording cells by modulating the irradiation time of the laser beam in five levels or more in correspondence to the information to be recorded. The reflectance of the virtual recording cells modulates in many levels and the reflection level of the reading laser beam during regeneration is changed in five levels or more. The optically transparent substrate is made of a plastic with a glass transition point (Tg) of 160&deg; C. or less. The reflecting film is a metal with a coefficient of thermal conductivity of 300 k/W&middot;m &middot;K or more and a film thickness of 50 nm or more.

The irradiation time and/or the irradiation power of a laser beam is varied to perform multi-level recording on a recording layer in five stages or more. On the recording layer of an optical recording medium , defined contiguously are virtual recording cells within a groove along tracks arranged at track pitches of 1 to 1.5 &mgr;m. The time and/or the irradiation irradiation power of the laser beam is modulated in five stages or more corresponding to the information to be recorded on each of the virtual recording cells in order to form recording marks A- G having five stages or more of different sizes and/or optical transmittance. The overall optical reflectivity of each of the virtual recording cells is modulated in multi-stages to vary in five stages or more the entire reflectivity level of the reading laser beam used upon reading in the virtual recording cell including the outside of the recording mark.

An optical recording medium ( ) is adapted such that information is recorded by forming recording marks on a recording layer ( ) that covers grooves ( ) of an optical transparent substrate ( ). In the recording layer ( ), contiguously defined along a feed direction S of irradiation are virtual recording cells ( ) which have a given unit length in the feed direction S of irradiation along the groove and a given unit width in the direction orthogonal thereto. In addition, the groove width W is set so that 0.20&times;(&lgr;/NA)<W<0.50&times;(&lgr;/NA), where &lgr; is the wavelength of a laser beam to be irradiated with and NA is the numerical aperture of the objective lens for the laser beam in a irradiation optical system. The irradiation time is set in five stages or more to radiate the laser beam, thereby making it possible to record information in multi-levels.

There are provided a spin coating method and an apparatus for forming a thin film having a uniform thickness on a substrate at a low cost in a process for manufacturing semiconductors, optical disks and the like. A coating solution is dropped onto the surface of a substrate ( ) to be coated, mounted on a horizontal turn table ( ) through a discharge nozzle ( ) and the substrate is turned to form a thin film. After the coating solution is dropped through the nozzle, a stand-by nozzle tip ( ) is soaked and held in a nozzle soaking solution ( ) having a composition near or equivalent to that of the coating solution. The crystal deposition of the solute is suppressed. Inter alia, the present invention is useful when a solution containing a solute having high crystallizability is coated.

Spin coating method and coating apparatus

Fluorinated alcohol for manufacturing optical recording medium and optical recording medium using the same

Optical recording medium and process for producing the same

In an optical disc, a first cover layer comprising a filler and a binder is formed on a protective coat, and a second cover layer of at least 0.1 .mu.m thick comprising at least 80% by weight of vinyl pyrrolidone polymer having Mw.gtoreq.30,000 is formed on the first cover layer. The second cover layer is printable with water-based ink. There is obtained an optical disc having a label surface which is printable with water-based ink to form characters and images which are erasable for correction.

Optical disc having printable label layer

In an optical recording disk comprising a reflective layer in close contact with a recording layer, the recording layer contains a phthalocyanine dye and a second dye having a lower heat decomposition temperature than the phthalocyanine dye. By virtue of a depression of heat decomposition temperature, recording sensitivity is improved.

Optical recording disk

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Tokyo, Japan

Hiroyuki Arioka