Abstract: An optical recording/reproduction method and device that can perform control for optimizing the amount of spherical aberration in a multilayered optical disc in a short period of time. When the objective lens is displaced in the focusing direction, the amplitude value of the focusing error signal detected just after leaving the focal position of a given first recording layer and the amplitude value of the focusing error signal detected just before passing through the focal position of a given second recording layer other than the first recording layer are measured with a particular spherical aberration, the amplitude ratio of amplitude values is calculated, the difference between spherical aberration and the optimal spherical aberration for the second recording layer is approximated as a function of the amplitude ratio, the optimal spherical aberration is calculated on the basis of this approximation, and the spherical aberration is set.

Abstract: The optical disk device can stably control an aberration correction lens even when one end of a movable range of the aberration correction lens is set as a reference position. The optical disk device comprises an optical pickup unit including the aberration correction lens and a stepping motor for moving the aberration correction lens, wherein, when an optical disk is inserted into the optical disk device, the aberration correction lens is moved to the reference position within the movable range and near one end thereof, and wherein, when moving the aberration correction lens to the reference position, driving pulses are applied to the stepping motor to press the aberration correction lens against the one end of the movable range, and thereafter a predetermined number of pulses are applied to reversely rotate the stepping motor and to set a stop position where the aberration correction lens stops as the reference position.

Abstract: An integrated circuit is provided in an optical disc apparatus for drawing a visible image on an optical disc including a discoloration layer which is discolored by heat or light by irradiating the optical disc with laser light. The integrated circuit includes a tracking direction displacement section configured to execute, when the visible image is drawn, oscillation control to oscillate a position irradiated with the laser light in a radial direction of the optical disc, and a laser modulation section configured to change, when the visible image is drawn, an intensity of the laser light so that the higher a displacement rate of the position irradiated with the laser light in the radiation direction is, the higher the intensity of the laser light becomes.

Abstract: A method for determining an optimal combination of focus bias and spherical aberration compensating value (SA value) in an optical disc drive is provided. Firstly, a first focus bias is set, the SA values are adjusted and the corresponding tracking error signal values are measured. Second-order-approximation is performed to obtain a first maximum value of tracking error signal. Secondly, a second focus bias is set, the SA values are adjusted and the corresponding tracking error signal values are measured. Second-order-approximation is performed to obtain a second maximum value of tracking error signal. Thirdly, a third focus bias is set, the SA values are adjusted and the corresponding tracking error signal values are measured. Second-order-approximation is performed to obtain a third maximum value of the tracking error signal. The three maximum values are compared to obtain the optimal combination of focus bias and SA compensating value in the optical disc drive.

Abstract: The relation between the cover layer thickness of a data recording surface and ratio ? of SCO to SCD is previously calculated and stored in a storage unit, where SCD denotes coma aberration which occurs when the data recording medium is tilted by unit angle and SCO denotes coma aberration which occurs when the objective lens is tilted by unit angle. When ?1 denotes ratio ? for a data recording surface corresponding to the smallest cover layer thickness, tilting angle ?1 of the objective lens is determined based on the ?1 and a tilt adjustment of the objective lens is made. Also, when ?2 denotes ratio a for a target data recording surface, tilting angle ?2 of the objective lens is estimated based on the ratio of ?2 to ?1 and a tilt correction of the objective lens is made.

Abstract: A multilayer optical disc which has three or more recording layers and enables easy positioning of a focused beam spot onto a particular recording layer in which a BCA is disposed. An inter-layer distance between a particular recording layer and a recording layer adjacent to the particular recording layer is larger than the other inter-layer distances in which, at the focused beam spot positioning, the focused beam spot traverses the said adjacent recording layer earlier than the other recording layer adjacent to the particular recording layer.

Abstract: A semiconductor laser emits infrared laser light for CD and red laser light for DVD. A collimator lens and a CD/DVD objective lens have optical axes thereof aligned with an optical axis of the infrared laser light. The CD/DVD objective lens is mounted on a holder to be inclined in such a direction as to suppress inherent coma aberration of the CD/DVD objective lens, and to suppress astigmatism generated in the red laser light from a state in parallel to a reference plane of the holder.

Abstract: There is proposed an optical disk recording method that can prevent degradation of recording quality due to occurrence of thermal interference, and an optical disk recording reproduction device used in this recording method.

Abstract: A new optical recording medium capable of reducing the burden in erasing data in the optical recording medium is provided. The optical recording medium includes an organic pigment recording layer 12 and a light reflecting layer 14, which are at least laminated on a substrate 11, wherein a photocatalyst layer 13 is formed in contact with the organic pigment recording layer 12.

Abstract: An optical pickup device includes a light source, a movable condensing lens, a rising prism or a rising mirror, an objective lens, and a phase plate. The light source emits laser light, and the movable condensing lens converts the laser light into converging light or diverging light. The rising prism or the rising mirror converts an optical axis of laser light passing through the condensing lens into a substantially vertical direction. The objective lens condenses the laser light, of which the optical axis is converted by the rising prism or the rising mirror, to an optical disk. The phase plate is provided between the condensing lens and the objective lens, and includes stepped portions that are formed at portions facing each other and have different thicknesses. The phase plate corrects astigmatism, which is generated by the rising prism or the rising mirror, by making a part of laser light having a size larger than a predetermined size pass through the stepped portions of the phase plate.

Abstract: An aberration correcting apparatus is provided, which is capable of suppressing occurrence of abnormal operation in an actuator for a tracking servo by reducing track cross noise caused by astigmatism in a 45-degree direction in which influence is exerted on the tracking servo. A control is performed by using a CPU 12 and a selector 3 so as to optimize an astigmatism correction amount in a liquid crystal panel in a state where a tracking servo loop is open and in a state where the tracking servo loop is closed.