Abstract: A centering method for holding a lens, which has been molded using a molding die, between a pair of holders of a bell clamp system, and centering the outer circumference of the lens, this method including: a first step of using a planar part of the lens, formed using a molding surface of a molding die, to position the lens with respect to a guidance part of a positioning member configured to enable the positioning of the lens, and a second step of holding the lens between one and the other holders and another holder so that the optical axis of the lens positioned in the first step aligns with the central axis of the one holder. It is possible to prevent the optical surface of the workpiece lens and an antireflective film from being scratched when centering an aspherical lens or a spherical lens as the workpiece lens.

Abstract: An optical disk drive includes a servo control unit 7 for causing an optical disk A to be driven; an optical pickup 2 for reading recorded data from the recording surface of the optical disk A after carrying out focus pulling-in of an object lens; a CPU 8 for controlling the servo control unit 7 and optical pickup 2 to perform readout operation of data recorded on the optical disk A; and a temperature detecting unit 9 for detecting temperature in the optical disk drive. The CPU 8 calculates the focus pull-in level in accordance with the temperature detected by the temperature detecting unit 9, and carries out the focus pulling-in of the optical pickup 2 using the focus pull-in level.

Abstract: An optical disk drive includes a servo control unit 7 for causing an optical disk A to be driven; an optical pickup 2 for reading recorded data from the recording surface of the optical disk A after carrying out focus pulling-in of an object lens; a CPU 8 for controlling the servo control unit 7 and optical pickup 2 to perform readout operation of data recorded on the optical disk A; and a temperature detecting unit 9 for detecting temperature in the optical disk drive. The CPU 8 calculates the focus pull-in level in accordance with the temperature detected by the temperature detecting unit 9, and carries out the focus pulling-in of the optical pickup 2 using the focus pull-in level.

Abstract: A method of manufacturing glass materials for press molding comprising a film-forming step in which hydrocarbon is fed into a reaction chamber containing a glass material and the fed hydrocarbon is thermally decomposed to form a carbon-based film on the surface of the glass material. In the film-forming step, a cycle comprising a sub-step of feeding and thermally decomposing hydrocarbon and a sub-step of subsequently evacuating the reaction chamber is conducted two or more times. A method of manufacturing optical glass elements comprising heat softening and press molding a glass material having on the surface thereof a carbon-based film obtained by the above manufacturing method. Provided is a glass material for press molding permitting the prevention of flaws and cracks during the molding of an optical glass element and permitting the prevention of fogging of the optical glass element following molding.

Abstract: A disk reproducing device in which an error rate comparison and parameter determination block newly determines a parameter to minimize the error rate and a parameter setting block newly resets the determined parameter to a read block in accordance with the determination of readjustment determination block, when the data of use environmental information from a pickup, environmental change detection block, and vibration detection block is data showing a predetermined change and an error rate from error rate measurement block becomes worse than a minimum error rate stored in error rate storage block by a predetermined amount or more.