Tdk Corporation

Takashi Horai

Hiroyuki Arioka

Syuji Tsukamoto

Narutoshi Fukuzawa

Hiroshi Take

Hiroyuki Yamada

Hideki Sasaki

Shirou Ootsuki

Motohiro Inoue

Takayuki Maruyama

Shuji Tsukamoto

A gas detection material having a Hofmann type porous coordination polymer of {Fe(pz)[Ni(CN)]} (wherein, pz=pyrazine) which contains ferrous ion, tetracyanonickelate ion and pyrazine as the essential ingredients and has a pillared crystal shape. Also a lithium ion secondary battery, wherein, the outer package of the lithium ion secondary battery is covered by the gas detection material mentioned above.

Gas detection material, gas detection tape and lithium ion secondary battery

The present invention provides an optical recording medium that includes a recording layer composed mainly of an organic compound and can utilize blue-violet semiconductor laser light (390 to 420 nm in wavelength) as recording/reproducing laser light. The present invention also provides an optical recording/reproducing method using the optical recording medium. The optical recording mediumcomprises at least a supporting substrate; a recording layeron the supporting substrate, the recording layercontaining an organic compound as a major component; and a light-transmitting layeron the recording layer, the light-transmitting layerbeing capable of transmitting laser light with a wavelength of 390 to 420 nm for recording and reproducing information. The organic compound in the recording layerincludes a trimethine cyanine dye that has the minimum value nof its refractive index n (real part of the complex refractive index) within the range of 370 to 425 nm and has a refractive index n of 1.2 or lower with respect to the wavelength of the recording/reproducing laser light. The organic compound, when absorbing the laser light, melts or degrades to bring about a change in the refractive index, thereby effecting recording of the information.

Optical recording medium and optical recording/reproducing method

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

A method is provided for recording data in a write-once type optical recording medium which can record data by forming a recording mark having a desired length and reduce jitter of a reproduced signal. The method comprises determining a pulse train pattern so that a level of a pulse is switched from the level corresponding to the level of the recording power Pw to the level corresponding to the level of the bottom power Pb in accordance with the length of a blank region to be formed immediately after formation of a first recording mark and the length of a second recording mark formed subsequent to the formation of the first recording mark.

Method for recording data on optical recording medium, device for recording data on optical recording medium, and optical recording medium

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

Magnetic read/write system and magnetic recording medium

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.

Growing community of inventors

Tokyo, Japan

Takashi Horai