Abstract: In a recording medium, an extension address is obtained without changing the number of bits of the address embedded in the wobble. The wobble address is partially or wholly encoded to embed the address information. At the time of reproducing the address information, the original address information is obtained by restoring the embedded information by the decoding process.

Abstract: The controller includes a deflection signal generator for generating a deflection signal for causing the electron beam to deflect and perform overwriting so that a beam spot of the electron beam follows the translation of the substrate over a period during which the substrate is rotated over a predetermined number of overwriting cycles; and a data output unit for outputting the drawing data, wherein, the deflection signal generator generates a deflection adjustment signal for irradiating the electron beam at a starting position for drawing a concentric circle to be subsequently overwritten after a predetermined deflection adjustment period has elapsed since overwriting of concentric circles based on the drawing data has completed.

Abstract: In a recording medium, an extension address is obtained without changing the number of bits of the address embedded in the wobble. The wobble address is partially or wholly encoded to embed the address information. At the time of reproducing the address information, the original address information is obtained by restoring the embedded information by the decoding process.

Abstract: A configuration for reading out disc management information easily without errors from a disc in which recording is conducted with data recording densities of a plurality of kinds. An optical disc includes a plurality of data recording areas in which information is recorded with data recording densities which are different from each other. Information of the data recording densities in the data recording areas is recorded in a management information recording area (a BCA area or a PIC area) by using a unique format which does not depend upon the data recording densities of the data recording areas. The divided data recording areas are disposed in the same plane of the disc, or disposed over a plurality of recording layers.

Abstract: The present invention enables a comprehensive evaluation from both of data read from a disk and a servo signal of a servo controller. The present invention provides a semiconductor integrated circuit mountable to a disk recording and reproducing drive, which comprises a signal processor of an RF signal read from a pickup, a servo controller responsive to a servo error signal read from the pickup, a memory controller, and an external interface. The memory controller is supplied with read data and a servo signal and stores the read data and the servo signal in a buffer memory according to a time division process. The read data and the servo signal stored in the buffer memory can be transferred to an external device via the external interface by the memory controller.

Abstract: Recording capacity per layer is detected from a disc and bit allocation of wobble addresses in a conventional optical disc and bit allocation in a high-density optical disc are controlled selectively to detect physical position addresses on the disc. Address detection can be performed for two kinds of discs which are equal in structure of addresses embedded in wobbles but different in bit allocation of addresses.

Abstract: A magnetoresistive element according to an embodiment includes: a base layer; a first magnetic layer formed on the base layer, and including a first magnetic film having an axis of easy magnetization in a direction perpendicular to a film plane, the first magnetic film including MnxGa100-x (45?x<64 atomic %); a first nonmagnetic layer formed on the first magnetic layer; and a second magnetic layer formed on the first nonmagnetic layer, and including a second magnetic film having an axis of easy magnetization in a direction perpendicular to a film plane, the second magnetic film including MnyGa100-y (45?y<64 atomic %). The first and second magnetic layers include different Mn composition rates from each other, a magnetization direction of the first magnetic layer is changeable by a current flowing between the first magnetic layer and the second magnetic layer via the first nonmagnetic layer.

Abstract: A technique for investigating differences of composition and structural state of a recording layer of an optical disc along with other defects, such as scratches, contamination, warp and distortion, prior to video recording and for setting up appropriate recording conditions in compliance with this result to thereby perform recording is disclosed. In an optical disc recording device capable of recording information on an optical disc, a region to be investigated is defined based on the video recording reservation contents. Then, investigate and evaluate the disc state which can affect the recording quality in a target disc region to be recorded. Next, based on investigation/evaluation results, perform recording setup, recording speed setup, servo control setup and recording position setup to thereby perform the recording. By appropriately modifying the recording setup on a case-by-case basis, it is possible to achieve high-quality recording.

Abstract: Recording capacity per layer is detected from a disc and bit allocation of wobble addresses in a conventional optical disc and bit allocation in a high-density optical disc are controlled selectively to detect physical position addresses on the disc. Address detection can be performed for two kinds of discs which are equal in structure of addresses embedded in wobbles but different in bit allocation of addresses.

Abstract: According to one embodiment, a magnetoresistive element includes a first magnetic layer with a variable magnetization and an easy-axis in a perpendicular direction to a film surface, a second magnetic layer with an invariable magnetization and an easy-axis in the perpendicular direction, and a first nonmagnetic layer between the first and second magnetic layers. The first magnetic layer comprises a ferromagnetic material including an alloy in which Co and Pd, or Co and Pt are alternately laminated on an atomically close-packed plane thereof. The first magnetic layer has C-axis directing the perpendicular direction. And a magnetization direction of the first magnetic layer is changed by a current flowing through the first magnetic layer, the first nonmagnetic layer and the second magnetic layer.

Abstract: There is a need to accurately lock focus of a laser beam onto a target data layer of a multilayer optical disc. The above need can be addressed by, for example, performing a focus lock operation after a spherical aberration correction amount is set in such a way as to make smaller the ratio of the focus error signal waveform amplitude at the data layer adjacent to a target data layer through which a laser beam passes earlier than through the target data layer to the focus error signal waveform amplitude at the target data layer than that when the spherical aberration correction amount is set so as to be optimal for the target data layer.

Abstract: According to one embodiment, a magnetoresistive element includes a first magnetic layer with a variable magnetization and an easy-axis in a perpendicular direction to a film surface, a second magnetic layer with an invariable magnetization and an easy-axis in the perpendicular direction, and a first nonmagnetic layer between the first and second magnetic layers. The first magnetic layer comprises a ferromagnetic material including an alloy in which Co and Pd, or Co and Pt are alternately laminated on an atomically close-packed plane thereof. The first magnetic layer has C-axis directing the perpendicular direction. And a magnetization direction of the first magnetic layer is changed by a current flowing through the first magnetic layer, the first nonmagnetic layer and the second magnetic layer.

Abstract: A data reproduction method and apparatus includes first circuitry to produce an information signal from a storage medium. The information signal includes copy control information. Detection circuitry is provided to detect the copy control information. Control circuitry is provided to operate the first circuitry to selectively output the information signal based on the detection result of the detection circuitry.

Abstract: Recording capacity per layer is detected from a disc and bit allocation of wobble addresses in a conventional optical disc and bit allocation in a high-density optical disc are controlled selectively to detect physical position addresses on the disc. Address detection can be performed for two kinds of discs which are equal in structure of addresses embedded in wobbles but different in bit allocation of addresses.

Abstract: A multilayer optical disc has dimples and/or bumps on a surface of at least one of the layers. Dimensions of the dimples and/or bumps, such as size, frequency and pitch, are selected to generate frequency components in light reflected from the surface that are different from frequency of servo and/or information signals. A disc drive can then use an appropriate filter to remove signals produced by light reflections of an unintended layer.

Abstract: According to one embodiment, a magnetoresistive effect element includes a first magnetic layer including perpendicular anisotropy to a film surface and an invariable magnetization direction, the first magnetic layer having a magnetic film including an element selected from a first group including Tb, Gd, and Dy and an element selected from a second group including Co and Fe, a second magnetic layer including perpendicular magnetic anisotropy to the film surface and a variable magnetization direction, and a nonmagnetic layer between the first magnetic layer and the second magnetic layer. The magnetic film includes amorphous phases and crystals whose particle sizes are 0.5 nm or more.

Abstract: A magnetoresistive element according to an embodiment includes: a first and second magnetic layers having an easy axis of magnetization in a direction perpendicular to a film plane; and a first nonmagnetic layer interposed between the first and second magnetic layers, at least one of the first and second magnetic layers including a structure formed by stacking a first and second magnetic films, the second magnetic film being located closer to the first nonmagnetic layer, the second magnetic film including a structure formed by repeating stacking of a magnetic material layer and a nonmagnetic material layer at least twice, the nonmagnetic material layers of the second magnetic film containing at least one element selected from the group consisting of Ta, W, Hf, Zr, Nb, Mo, Ti, V, and Cr, one of the first and second magnetic layers having a magnetization direction that is changed by applying a current.

Abstract: According to one embodiment, a magnetoresistive element includes a first magnetic layer with a variable magnetization and an easy-axis in a perpendicular direction to a film surface, a second magnetic layer with an invariable magnetization and an easy-axis in the perpendicular direction, and a first nonmagnetic layer between the first and second magnetic layers. The first magnetic layer comprises a ferromagnetic material including an alloy in which Co and Pd, or Co and Pt are alternately laminated on an atomically close-packed plane thereof. The first magnetic layer has C-axis directing the perpendicular direction. And a magnetization direction of the first magnetic layer is changed by a current flowing through the first magnetic layer, the first nonmagnetic layer and the second magnetic layer.

Abstract: It is an object of the invention to provide a multi layer optical disc that can be used effectively and an optical disc apparatus that can cope with the multi layer optical disc. The object described above can be accomplished by providing redundancy to the number of layers of the multi layer optical disc. The object can also be accomplished by providing reproducing/recording unit of the multi layer optical disc to the optical disc apparatus.

Abstract: A magneto-resistive device has a magnetic free layer (33), a magnetic pinned layer (31) having a magnetic moment larger than that of the magnetic free layer, and an intermediate layer (32) provided between the magnetic free layer and the magnetic pinned layer. The negative-resistance device is characterized in that the negative-resistance device shows negative resistance by making the magnetic free layer continually change the magnetization direction along with the increase of the voltage which is applied to a magneto-resistive device so that electrons flow into the negative-resistance device from a magnetic free layer side.