Tdk Corporation

Toshifumi Tanaka

Hideki Hirata

Naoki Hayashida

Toshihiko Ishida

Atsuko Motai

Osamu Murakami

Yasuo Ohira

Setsuko Shibuya

Satoshi Maruyama

Kazushi Tanaka

Tsuyoshi Komaki

Kazuya Ogawa

Tsuyoshi Iijima

Kazuki Suzawa

Michiki Naganawa

A method for using a low-cost artificial fingerprint liquid for quantitatively and with a good reproducibility evaluating an anti-staining property, and a fingerprint adhering property or a fingerprint removing property on the surface of an optical disk such as a reproduction-only optical disk, optical recording disk, magneto-optical recording disk, various displays such as a CRT, and various substances such as glass. A stamp is used to transfer the artificial fingerprint solution to the surface to be tested. An artificial fingerprint liquid comprising a fine-particle-form substance and a dispersion medium capable of dispersing the fine-particle-form substance. The dispersion medium preferably has a surface tension ranging from 20 to 50 mN/m at 25&#xb0; C., and preferably is selected from at least one of higher fatty acid, derivative of higher fatty acid, terpens, and derivatives of terpens. The fine-particle-form substance is at least one selected from inorganic fine particles and organic fine particles.

Artificial finger print liquid, testing method for optical information medium using it, and optical information medium

The method of charging a lithium ion secondary battery uses a lithium ion secondary battery comprising a positive electrode including a mixed metal oxide containing at least Li, Mn, and Ni as metal components as a positive electrode active material, a negative electrode, and a nonaqueous electrolytic solution containing a lithium salt; and includes a constant current charging step of carrying out constant current charging with a set charging current value Icorresponding to a set value nC satisfying the condition represented by the expression of 2C&#x2266;nC&#x2266;60C, where C is a rated capacity value of the lithium ion secondary battery, and n is a number of 2 to 60.

Method of charging lithium ion secondary battery including a constant current, charging apparatus, and power supply apparatus

A low-cost artificial fingerprint liquid for quantitatively and with a good reproducibility evaluating an anti-staining property, and a fingerprint adhering property or a fingerprint removing property on the surface of an optical disk such as a reproduction-only optical disk, optical recording disk, magneto-optical recording disk, various displays such as a CRT, and various substances such as glass including a fine-particle-form substance and a dispersion medium capable of dispersing the fine-particle-form substance.

An optical recording medium has a plurality of laminated information recording layers. The average reflectivity within a stipulated range in the unrecorded regions of at least one of the information recording layers has a value between the reflectivity in the crystalline state and the reflectivity in the amorphous state. When the focus of the laser beam is aligned to one information recording layer, the difference in reflectivity is small between the case in which those regions of the other information recording layer on which the beam spot shines is a recorded region and the case in which it is an unrecorded region, and even in the case that a boundary between a recorded region and an unrecorded region is present within the beam spot, the distribution of reflectivity within the beam spot becomes constant, so the stable recording and/or playback can be performed.

Optical recording medium and method of manufacturing same

The present invention provides a low-cost artificial fingerprint liquid for quantitatively and with a good reproducibility evaluating an anti-staining property, and a fingerprint adhering property or a fingerprint removing property on the surface of an optical disk such as a reproduction-only optical disk, optical recording disk, magneto-optical recording disk, various displays such as a CRT, and various substances such as glass. An artificial fingerprint liquid comprising a fine-particle-form substance and a dispersion medium capable of dispersing the fine-particle-form substance. The dispersion medium preferably has a surface tension ranging from 20 to 50 mN/m at 25&#xb0; C., and preferably is selected from at least one of higher fatty acid, derivative of higher fatty acid, terpens, and derivatives of terpens. The fine-particle-form substance is at least one selected from inorganic fine particles and organic fine particles. The present invention provides a testing method for an optical information medium using the artificial fingerprint. The present invention provides an optical information medium which is good in the property of wiping off an organic stain, such as a fingerprint, adhering to a surface of the optical recording medium and which can maintain good recording/reproducing property over a long period.

A testing method for an optical information medium using an artificial fingerprint. The artificial fingerprint is made of an artificial fingerprint liquid comprising a fine-particle-form substance and a dispersion medium capable of dispersing the fine-particle-form substance.

A write-once or rewritable multilayer optical recording medium according to the present invention includes an Lrecording layer and an Lrecording layer, in which data recording areas for recording data are respectively formed, laminated on one surface of a base, wherein a read-in area for recording the data management information of all the data recorded in the respective data recording areas of the Lrecording layer and the Lrecording layer is formed only in the Lrecording layer. This means that the data management information of all the data can be read out quickly by simply accessing the Lrecording layer and the recording and reading of the data can be executed quickly and easily.

Multilayer optical recording medium, method for recording data, and recorder

An optical information medium comprising a supporting substrate, an information recording area on the supporting substrate, and a light-transmitting layer covering at least the information recording area, wherein the information recording area is irradiated with the recording/reading laser beam through the light-transmitting layer, and wherein the light-transmitting layer is highly scratch resistant upon contact with the optical pickup is provided. Also provided is an optical information medium which has a scratch-resistant light transmitting layer, and which experiences reduced vibration in high-speed rotation without suffering from problems in focus servo and tracking servo. In such optical information medium, the surface of the medium on the side of the laser beam incidence at least in the part above the information recording area has a dynamic coefficient of friction of up to 0.4.

Optical information medium

An optical information medium has a light-transparent substrate and an information recording layer, wherein optical recording and/or reading is performed with a laser beam that enters the information recording layer from the light-transparent substrate side. A cured polysilazane film is disposed on the laser beam incident side of the light-transparent substrate, and the light-transparent substrate or the light-transparent substrate having the cured polysilazane film integrated thereon has a tensile modulus of at least 200 MPa. The medium on its laser beam incident side surface is improved in mar resistance.

Optical information medium and evaluation method

An optical disk substrate of resin, comprising a center hole and being composed of an inner circular-projected portion and an outer flat circumferential portion, the inner circular-projected portion having a circular projection projecting from at least one major surface of the substrate, the maximum height of the circular projection measured from the major surface of the outer flat circumferential portion being equal to or larger than 0.5 mm, the optical disk substrate is designed to satisfy the following equation or inequality: V/V.sub.0 &lt;1.5, where V stands for the volume of the circular-projected portion, and V.sub.0 stands for the volume of an annular body having the same radius as the circular-projected portion and the same thickness as the outer flat circumferential portion, and having a center hole of the same size as the center hole.

Optical disk substrate and optical disk using the same

A disc molding apparatus capable of satisfactorily accomplishing release of a molded disc without any trouble to eliminate deformation of the disc during the release and improve quality, reliability and productivity of the disc. In the disc molding apparatus, an air inlet port is provided in proximity to an outer stamper holder of an outer ring for supplying air toward a central region of a disc molded in a cavity of a mold body from a periphery of the disc and a communication passage communicating with the air inlet passage is provided at the outer ring, so that air may be more uniformly blown against the disc during release of the disc from a stamper.

Disc molding apparatus

An optical recording disk includes a resin substrate having a recording layer thereon and a protective glass substrate, which are joined into an integral disk such that the recording layer is inside. The resin substrate is formed of a resin composition comprising a specific cyclic polyolefin and an optional alkyl phenol condensate. The resulting lightweight, rigid disk is adapted for recording/reproducing operation at high rotational speeds with few focusing errors due to minimized axial runouts.

Optical recording disk

An optical recording disk is constructed using a substrate which is injection molded from a mixture of a cyclic polyolefin and up to 2% by weight of an alkyl phenol condensate. A recording layer remains firmly adhered to the substrate even in a hot humid environment.

Optical recording medium

Optical recording media include substrates of a larger diameter formed by injection molding a copolymer of ethylene with a cyclic olefin. The media are adapted for high speed rotation with the benefits of a high output, high C/N, and low noise level. When a protective substrate of glass is attached to the polyolefin substrate such that the recording layer is inside, there is obtained a light-weight rigid disk which experiences minimal axial runouts and hence, minimal focusing errors during high rotational speed operation.

An optical recording disk is constructed using an injection molded substrate of a cyclic polyolefin having a recurring structural unit of the formula: ##STR1## wherein R.sub.1 and R.sub.2 are independently selected from hydrocarbon groups. The disk has a diameter of at least 200 mm, and is rotated at 1,800 rpm or higher during recording/reproducing operation. Despite a larger diameter, the disk experiences minimized occurrence of double refraction during high speed rotation, ensuring high outputs with a high C/N and a low noise level.

Growing community of inventors

Tokyo, Japan

Toshifumi Tanaka