Abstract: An optical disc apparatus includes a laser diode for emitting a laser light, a beam splitter for dividing the laser light into a main beam and sub beam, a main photodetector for detecting the main beam to output a main push-pull signal, a sub photodetector for detecting the sub beam to output a sub push-pull signal, and a subtracter for calculating the main and sub push-pull signals to output a differential push-pull signal, in which an amplification degree of the sub push-pull signal is adjusted so that a DC offset on the differential push-pull signal is adjusted, even in the case where a laser intensity is varied.

Abstract: To provide a new recording method and recording apparatus with respect to an optical recording medium, the recording method and recording apparatus being able to deal with a high density of an optical recording medium of recent years. Recording of a recording track and a prepit is carried out by sequentially deflecting a single beam.

Abstract: Novel evaluation indexes are introduced to allow both a total evaluation of data recording and an evaluation of individual detection patterns. A data recording evaluation method includes a step of reproducing a result of data recording performed on an optical disk and identifying a predetermined detection pattern in a reproduction signal, a step of detecting a signal state of the reproduction signal associated with the predetermined detection pattern, and a first calculation step for calculating a first evaluation index value based on the detected signal state and a reference state identified from the predetermined detection pattern. When there is a plurality of predetermined detection patterns as described above, a second calculation step is further provided for calculating a second recording state evaluation index value using the first evaluation index value calculated from each of the predetermined detection patterns.

Abstract: An optical head that is restrained from becoming larger, even if it is used for an optical-information recording medium that includes a plurality of information recording layers. In this optical head, a collimating lens is formed by a concave lens disposed on the side of a light source and a convex lens disposed on the side of an objective lens. A collimating-lens actuator moves the convex lens in a direction where a spherical aberration is cancelled which is generated according to the thickness of a light transmission layer up to an information recording layer of the optical-information recording medium. An aperture stop is provided on the side of the collimating lens with respect to the objective lens, and the aperture stop is located near the focal position of the convex lens on the side of the objective lens.

Abstract: In an optical pickup capable of removing inter-layer crosstalk, a dark line that may appear in a central portion of a beam is removed. Thereby, an error in a data signal is reduced. Reflected light from a multi-layer disc is split into two parallel bundles with a splitting optical system in a way that the light is split at a central line. Thereby, when reflected light from a target layer is focused, the reflected light is not influenced from an attenuation element provided on an optical axis.

Abstract: An information recording medium 1 at least comprises a substrate 13 having a microscopic pattern 20, which is constituted by a shape of continuous substance of approximately parallel grooves formed with a groove section G and a land section L alternately, a recording layer 12 formed on the microscopic pattern 20 and a light transmission layer 11 formed on the recording layer. The microscopic pattern 20 is formed so as to satisfy a relation of P<?<NA and a thickness of the light transmission layer 11 is within a range of 0.07 to 0.12 mm, wherein P is a pitch of the groove section G or the land section L, ? is a wavelength of reproducing light beam and NA is a numerical aperture of an objective lens. Further, there provided an information recording medium, which is improved in cross erase and recorded in high density, and a reproducing apparatus and a recording apparatus for the information recording medium.

Abstract: A write once disc allowing management of a data area, a method of managing the data area of the write once disc, an apparatus recording data on the write once disc, an apparatus and method of reproducing data from a write once disc. The write once disc, includes a lead-in zone, a data area, and a lead-out zone. The write once disc includes a predetermined area storing area allocation information which indicates whether at least one section of the data area is allocated for disc defect management. In the disc and method, area allocation information specifying a structure of the data area is recorded on the disc, thus allowing a recording/reproducing apparatus to recognize the data area structure. Therefore, allocating areas, such as a spare area, for disc defect management other than an area for storing user data, to the data area is possible. The allocation of the areas for disc defect management to the data area enables effective use of the write once disc.

Abstract: A method of detection is described to be used in file system-based player devices to determine the type of compact disk that has been inserted into a player. The method automatically distinguishes between the DTS-CD format and standard audio CDs. The method allows the operating system or CPU software to take appropriate action to decode and playback the audio stream once the a decision between standard audio CD or DTS-CD is made.

Abstract: The optical disk recording apparatus has the function of correcting the timing shift of the write strategy signal caused by the change in the operating environment of the digital signal processing circuit including the write strategy generating circuit, the laser drive circuit for driving the laser at the time of recording and the flexible printed board for electrical connection between the digital signal processing circuit and the laser drive circuit. Upon determination that the timing shift correction is required, the timing shift is reduced by operating the timing shift correcting function.

Abstract: An optical pickup apparatus comprising: a laser diode; an objective lens configured to focus laser light emitted from the laser diode on a signal recording layer of an optical disc; a first aberration correction element arranged in an optical path between the laser diode and the objective lens; and a second aberration correction element arranged in the optical path between the laser diode and the objective lens and having an aberration correction speed lower than the aberration correction speed of the first aberration correction element, the first aberration correction element and the second aberration correction element being selectively operated according to the required aberration correction speed.

Abstract: A gap controller according to the present invention can set a reference level reasonably for a gap control that needs to be done to keep the gap between a solid immersion lens (SIL) and an optical disc constant. With the gap varied at a substantially regular step, gap detection signal levels are logged to find an extreme value of its second-order difference. And the gap control reference level is determined by the gap detection signal level that results in that extreme value.

Abstract: An information recording medium having at least a read only area and a recording and reproducing area is composed of at least: a substrate; a recording layer formed on the substrate so as to record and reproduce information; and a light transmission layer having transparency formed on the recording layer. The information recording medium is further characterized in that a wobbling groove corresponding to the read only area and another wobbling groove corresponding to the recording and reproducing area is formed on the substrate without overlapping with each other, the recording and light transmitting layers are continuously adhered over at least two areas of the read only area and the recording and reproducing area, reflectivity of the recording layer is more than 5%, and a push-pull signal output T3 reproduced from the read only area and another push-pull signal output T4 reproduced from the recording and reproducing area before recording satisfies relations of T3?0.1, T4?0.1 and 1.5?T3/T4?0.5.

Abstract: A write strategy for use in recording is determined from recommended write strategy parameters recorded on an optical disk (160) and the characteristics of the optical recording device used in recording; a recommended asymmetry value is determined from the difference between the numerical aperture NA1 of the objective lens, which is a recording condition of the recommended asymmetry value recorded on the optical disk (160) and the numerical aperture NA2 of the objective lens (150) of the optical recording device used in recording, and recording is carried out on the optical disk (160) according to the write strategy and asymmetry value thus determined. Optimal recording can be carried out even on an optical disk for which the optimal write strategy information has not been determined in advance, without the need to store write strategy information suitable for each and every optical disk.

Abstract: A recording medium (100) is provided with: a first recording layer (L0) and a second recording layer (L1) to record therein record information, and a control area (102, 118) in said recording layer and a control area in said second recording layer to record therein control information for controlling at least one of recording and reproduction of the record information, wherein a distance between an inner radius of the control area in the first recording layer and an outer radius of the control area in the second recording layer is larger than or equal to a first predetermined value.

Abstract: According to one embodiment, a system includes a plurality of synchronous servo channels, where each channel receives a signal from a servo reader of a magnetic head. The system also includes logic for estimating a tape velocity, logic for determining a first and second time instant representing a time at which a flag is generated by a related servo channel, logic for determining a first and second correction term representing a time difference between a time at which a peak of a correlation signal and a time at which the flag occur, logic for calculating a skew error estimate based on a reference shift value associated with a servo band pair being spanned by a head module, and logic for applying a control signal including a skew correction that corresponds to the calculated skew error estimate to the skew-following loop. Other systems and methods are disclosed as well.

Abstract: Various embodiments of the present invention provide systems and methods for reduced latency feedback in a data processing system. For example, some embodiments provide a data processing system that includes a variable gain amplifier, a processing circuit, a data detector, and an error signal calculation circuit. The variable gain amplifier amplifies a data input signal and provides an amplified signal. The processing circuit generates a signal output corresponding to the amplified signal, and includes a conditional multiplication circuit. The conditional multiplication circuit conditionally multiplies the signal output by a gain correction signal and provides the result as an interim output. The data detector applies a data detection algorithm to the signal output and provides an ideal output. The error signal calculation circuit generates a gain correction signal based at least in part on the interim output and a derivative of the ideal output.

Abstract: A method and apparatus for recording data on an optical disk calculates an optical power at a first recording speed, compares the calculated optical power to a predetermined value, and then determines whether to apply the first recording speed based on a result of the comparison. The optical power at the first recording speed is calculated based on a reference optical power and a measured optical power, and the predetermined value may correspond to the maximum allowable power of a laser pickup. The method and apparatus may be used to control the speeding, timing, and/power of a data recording operation, as well as to compensate for temperature variations and/or power margins of one or more circuits in an optical disk device.

Abstract: An optical pickup device such that the driving force of the drive unit provided on the same optical base as that of the objective lens exerts no adverse influence on controlling of the objective lens is provided. The optical pickup device 1 has an objective lens 11 that condenses laser light onto an optical disk 3, a first drive mechanism 15 that moves the objective lens 11 on the optical base 6, a second drive mechanism 8 that moves a movable member 9 different from the objective lens 11 on the optical base 6, first control means 27 that outputs a first driving signal TDS to operate the first drive mechanism 15, and second control means 25 that outputs a second driving signal EDS to operate the second drive mechanism 8. A derivative value of the second driving signal EDS is added to the first driving signal TDS and inputted to the first drive mechanism 15.

Abstract: An information recording medium (100) is provided with: a first pre-recording area, in which reproducible preformed information including physical address information is recorded in advance and in which preformed address information assigned in advance is not recorded; a second pre-recording area, which is adjacent to the first pre-recording area and in which each of the preformed address information and unreproducible preformed information is recorded in advance; a first recording area, which is adjacent to the second pre-recording area and in which first record information is recorded and which is reproduced by an information reproducing apparatus in reproduction, the first record information including physical address information which can be reproduced by the information reproducing apparatus; and a second recording area, which is adjacent to the first recording area and in which predetermined second record information is recorded.

Abstract: Disclosed is an information recording medium (100) comprising a first recording layer (L0 layer) which is provided with a first recording track for recording record information, and a second recording layer (L1 layer) which is provided with a second recording track for recording record information. Each recording zone (zone #n) including one recording area in the first recording layer and another recording area in the second recording layer which is opposite to the recording area in the first recording layer has a management information recording area (RMA) for recording management information (RMD) for recording the record information.