Abstract: A head-slider configured to fly in proximity to a recording surface of a magnetic-recording disk. The head-slider includes a write element including a main pole configured to generate a magnetic-recording field from a pole tip of the main pole in a first localized portion of the magnetic-recording disk. The head-slider also includes a magnetic-recording assistance element configured to provide energy to a second localized portion of the magnetic-recording disk in order to increase reversibility of a magnetization in a first localized portion of the magnetic-recording disk. A width of the pole tip of the main pole on a leading-edge side is wider than a width of the pole tip of the main pole on a trailing-edge side.

Abstract: A multi-layered information recording medium including a plurality of recording layers, the multi-layered information recording medium comprising: a user data area for recording user data; and a plurality of spare areas including at least one replacement region, wherein when the user data area includes at least one defect region, the at least one replacement region may be used in place of the at least one defect region, wherein a first spare area of the plurality of spare areas is positioned so as to be contiguous to a first user data area of a first recording layer, a second spare area of the plurality of spare areas is positioned so as to be contiguous to a second user data area of a second recording layer, and the first spare area and the second spare area are positioned approximately at the same radial position on the multi-layered information recording medium.

Abstract: A method of performing writable optical recording of a medium to form multilevel oriented nano-structures therein, comprises steps of providing a disc-shaped, writable recording medium having a planar surface; and encoding data/information in the medium by forming a plurality of multilevel nano-structured pits in the surface by scanning with a focused spot of optical energy to form at least one data track therein, including scanning the optical spot in a cross-track direction while rotating the disc about a central axis.

Abstract: A writing method for a multilayer optical disc. The method includes: measuring and recording optimum internal gains obtained when the objective lens is located on each inner side of the pick-up head, respectively, checking the writing direction based on the specific writing direction on each data layer of the disc, selecting the inner optimum internal gain when the writing direction is toward outside, and selecting the opposite inner optimum internal gain when the writing direction is toward inside to minimize the offset of the tracking error signal.

Abstract: A method is described for writing an optical disc (2) having a multi-layered storage space (30) comprising at least a first storage layer (31) and a second storage layer (32) below the first layer (31). The method comprises the step of preventing a write operation to a portion of the second storage layer (32) located below a maiden portion of said first storage layer (31). In one embodiment, all blocks (40) which are physically located in the second storage layer (32) are incorporated in a defect list (DL) until a sufficiently large portion of the first storage layer (31) has been written at least once. In another embodiment, all blocks (40) which are physically located in the second storage layer (32) are covered by a system file with a predetermined name (“DUMMY”) until a sufficiently large portion of the first storage layer (31) has been written at least once.

Abstract: An information recording medium according to the present invention includes at least three information recording layers. If the readout power of a laser beam in reading information from an information recording layer L(n) is identified by Pw(n), and if the readout power of the laser beam in reading information from an information recording layer L(n+a) is identified by Pw(n+a), then a base thickness between the information recording layers is determined so that the intensity of the light when the information recording layer L(n+a) is irradiated with a laser beam having the readout power Pw(n) becomes equal to or lower than that of the light when the information recording layer L(n+a) is irradiated with a laser beam having the readout power Pw(n+a).

Abstract: A method and a device are disclosed for reducing a perceived discontinuity in a continuous digital information stream read back from a first (LO) and a second (L1) layer of a multi-layer record carrier (104), said discontinuity occurring during the transition from the first (LO) to the second (L1) layer. The method comprises the steps of monitoring (S1) said digital information stream to be recorded on said multi-layer record carrier (104), determining (S2) a time (ti) corresponding to a point in said digital information stream where an effect of a perceived discontinuity is reduced, and recording (S3) said digital information stream such that a transition from recording on the first layer (LO) to recording on the second layer (L1) of the multi-layer record carrier (104) occurs at said determined time (ti), thereby reducing perceived discontinuity that occurs in, for example, a read back device with a relatively small data buffer.

Abstract: Information is recorded on a multi-layered optical recording medium by irradiating it with a laser beam. The recording medium can form a first information recording layer that is the farthest from a light incident surface, a second information recording layer that is the second farthest from the light incident surface, and at least one third information recording layer that is located closer to the light incident surface than the second information recording layer is. At this time, if all the information recording layers other than the first information recording layer are either blank or have been completely recorded, then information is recorded on the first information recording layer. This allows for stabilizing the energy of a recording laser beam during recording and thereby providing improved recording quality.

Abstract: A multilayer optical recording medium includes three or more recording layers formed in a thickness direction. Trial writing areas provided in the respective recording layers to adjust the power of recording laser are formed not to overlap at a position in a planar direction in adjacent ones of the recording layers. Further, the trial writing areas are formed to have an overlapping portion at a position in the planar direction in one of the recording layers and at least another one of the recording layers not adjacent to the one of the recording layers.

Abstract: Provided is an optical disk apparatus which optimizes a frequency of a high frequency superimposing operation upon reproduction so that good reproduction performance is realized in a wide irradiation power range of a laser power. The optical disk apparatus includes: a semiconductor laser device; an optical disk discrimination circuit for performing laser discrimination; a driver device including a drive circuit for supplying direct drive current to the semiconductor laser device and a high frequency superimposing circuit for superimposing high frequency current on the drive current; and a high frequency superimposing variable circuit for changing a frequency of the high frequency current in which when information is reproduced, the high frequency superimposing variable circuit sets the frequency of the high frequency current for reproducing a multi-layer disk to be higher than the frequency of the high frequency current for reproducing a single-layer disk.

Abstract: A method of recording data in a multilayered recordable optical recording medium is disclosed. When test recording is executed in a multilayered recordable optical recording medium having N recording layers (N is an integer of 2 or more), a test recording range in a test recording area of an (m+1)th recording layer is shifted relative to a test recording range in a test recording area of an mth recording layer by an amount greater than a difference of decentration amounts between the mth and the (m+1)th recording layers or a maximum decentration amount in the N recording layers. The shifting direction is inverse to a test recording range adding direction in a radius direction of the recording medium.

Abstract: An information recording device (300) is provided with (i) a recording unit (301 or the like) for recording first information in a first recording layer (L0 layer) and for recording second information in a second recording layer (L1 layer) by a laser beam transmitted through the first recording layer, and (ii) a control unit (305 or the like) for controlling the recording unit to record dummy data as the second information, in a recording area of the second recording layer other than an area facing one recording area of the first recording layer, at the time of recording the first information in the one recording area.

Abstract: An information recording apparatus (300) is provided with: a first recording device (302 etc.) for recording the first information into a first area of the first layer; a second recording device (302 etc.) for recording the second information into a predetermined area of the second layer; and a controlling device (305) for controlling the second recording device to record the second information by the laser light, while displacing an edge indicating an innermost or outermost circumference of the predetermined area in which a penetrated area penetrated by the laser light is included in the first area, in a direction to approach an edge of the predetermined area in which the penetrated area is not included in the first area, only by a predetermined length corresponding to a tolerance of a change amount indicating a change in the reproduction quality.