Abstract: In a recording stop processing method according to an aspect of this invention, when a recording stop instruction is input and the data size of stream data, which is stored in a storage destination, is smaller than the predetermined data size, dummy data is added to the stream data stored in the storage destination, and the stream data with the dummy data, whose data size becomes equal to the predetermined data size, is DMA-transferred to terminate DMA transfer, thus stopping recording of stream data.

Abstract: A method and apparatus for controlling the power of a laser diode, which can prevent fluctuation in the laser power of the laser diode at a record/playback area of an optical disc. The apparatus for controlling the power of the laser diode includes a controller which controls an automatic power control of the laser diode (APC controller), interposed between an up/down counter and a laser diode driver, the APC controller latching the output of the up/down counter in synchronism with a periodic synchronization signal, and outputting the latch result to the laser diode driver. Therefore, the power level of the laser diode can be periodically controlled according to subdivided control modes, so that the laser power level remains resilient to external noise, compared to a continuous control operation through the entire mode.

Abstract: A record carrier has substantially parallel tracks having first variations of a first physical parameter and second variations of a second physical parameter of the track. The first variations represent information recorded on the record carrier, this information being recoverable by a controllable type of data processing. A modulation pattern of the second variations represents a code for controlling the type of data processing. In respect of a code track that includes the modulation pattern, the modulation pattern in the left neighboring track is aligned to the modulation pattern in the right neighboring track. Thereby crosstalk due to the second variations is decreased, and at least two tracks have the same modulation pattern. The playback device has a demodulator (50) and a control unit (56) for retrieving the code from at least two tracks.

Abstract: A drive current supply circuit is provided in which the speed of rise of the drive current to a laser diode is increased. In a drive current supply circuit for supplying drive current I to load 50 connected with the line 1R of two parallel lines 1R and 2R of a first current mirror circuit 1, this drive current supply circuit is provided with a control circuit CONT that controls the current i flowing in the other line 1L in accordance with first control signal ?ø1 and the first control signal ?ø1 comprises a steady DC component øD and a drive signal component ø1 added to the DC component øD when desired.

Abstract: A process for computing an eccentric amount of a disk upon rotating is provided. The process includes steps of starting a servo control system of a disk drive to rotate the disk at a specified angular velocity, measuring a track crossing speed of the servo control system at a focusing point on the disk, and computing the eccentric amount of the disk according to the specified angular velocity and the track crossing speed. A process for controlling rotation of a disk loaded in a disk drive is also provided. The process includes steps of realizing an eccentric amount of the disk, and rotating the disk at an operating speed corresponding to the eccentric amount.

Abstract: An optical disk apparatus configured to be compatible with a plurality of disk types includes an objective lens to focus a laser beam onto an optical disk provided in the apparatus. A drive mechanism is coupled to the objective lens to enable tilting of the objective lens to a plurality of tilt angles. A first signal detection circuit is configured to receive and process a first information signal associated with information read from the optical disk and to output a data signal derived from the first information signal. A second signal detection circuit is configured to receive and process a second information signal associated with information read from the optical disk and to generate a first track error signal. A third signal detection circuit is configured to receive and process a third information signal associated with information read from the optical disk and to generate a second track error signal.

Abstract: A method of reproducing information by scanning information marks, disposed with a predetermined mark pitch therebetween and recorded on tracks inside a predetermined information recording region, by an optical spot. The method includes detecting the size of the optical change resulting from the information mark, calculating a plurality of equalization coefficients used for an equalization processing for the size of the optical change detected for each of the information marks, and reducing the inter-symbol interference on the basis of the equalization coefficients by the equalization processing. The equalization coefficient used for the equalization processing of the size of the optical change by a first information mark is greater than said equalization coefficient used for the equalization processing of the size of said optical change by a second information mark which is longer than the first information mark.

Abstract: A method is designed for recording contents information along a track of an optical disk of a writeable type. A volume detection step is carried out for detecting an actual volume of the contents information to be recorded into the optical disk. A capacity detection step is carried out for detecting a nominal capacity of the optical disk, which indicates a rated volume of information to be recorded at maximum. A density determination step is carried out for determining a recording density of the contents information based on the detected actual volume and the detected nominal capacity. A record step is carried out for recording the contents information into the optical disk at the determined recording density such that the actual volume of the contents information can fit into the nominal capacity of the optical disk.

Abstract: An optical pickup apparatus for an optical disk drive records or reproduces data on or from an optical disk, includes an optical head section including an object lens focusing an incident light on the optical disk, a slider on which the object lens is mounted, wherein the slider floats over the optical disk by an air bearing generated between the optical disk and the slider, a bobbin on which the slider is mounted, and a flexure disposed between the slider and the bobbins elastically supporting the slider. A driving unit drives the slider in a tracking direction and a focusing direction. In the above construction, the slider floats over a recording surface of the optical disk due to an air bearing and a near field between the object lens and the optical disk can be controllably maintained.

Abstract: An optical pickup apparatus for recording and/or reproducing information for an optical information recording medium having a plurality of information recording layers, comprising: a light source to emit a light flux; and a converging optical system to converge the light flux emitted from the light source onto each information recording layer of the plurality of information recording layers. The converging optical system converges a light flux having an image side-numerical aperture of 1.0 or more onto the each information recording layer so as to conduct recording and/or reproducing information for the each information recording layer.

Abstract: An optical multi-level recording medium, having a recording layer on which a recording mark is formed by irradiating a laser beam, plural virtual recording cells being continuosly formed in a relative moving direction to the laser beam on the recording layer with an arbitrary unit length and a unit width, five stages or more irradiation times being set so that the irradiation time becomes long successively from the first to final stages, a power average value of laser beam in a specific irradiation time of the plural-stage irradiation times being set so as to become larger than a power average value of another irradiation time longer than the specific irradiation time, and recording marks being formed in the virtual recording cell and giving five stages or more different optical reflectance when the laser beam is irradiated to the virtual recording cell.

Abstract: A fast synchronization pull-in and an optimum error correction are achieved in a reproduction apparatus for reproducing data recorded on a recording medium even in the case where the quality of input data involving a seek or defect is low. A seek amount detection block 190 is provided, a seek change signal 201 is generated, and the width of a synchronization detection window pulse 161 and a correction algorithm in a correction block 230 are modified.

Abstract: An optical disc drive compatible with optical discs of different types, for example, is provided. For focusing, through an optical system used in common with the different types of optical discs, a laser beam emitted from a selected one of a plurality of light sources disposed apart from each other radially of the optical disc, the optical system is moved radially of the optical disc correspondingly to the selection of the light source for emitting the laser light. Namely, it is possible to prevent the optical property from being deteriorated when a single optical pickup is used in common with such optical discs of different types.

Abstract: A storage apparatus rotates an optical recording medium at two or more kinds of rotational speeds. The rotational speed is decreased when a read or write margin becomes less than or equal to a first predetermined value or, when a frequency of generation of a servo abnormality of a tracking servo and/or a focus servo is greater than or equal to a first predetermined frequency. On the other hand, the rotational speed is increased when the read or write margin becomes greater than or equal to a second predetermined value or, when the frequency of generation of the servo abnormality of the tracking servo and/or the focus servo is less than or equal to a second predetermined frequency.

Abstract: A digital data processor comprising a stack storage having a plurality of locations classified into two or more banks, and a stack pointer circuit pointing to one or more stack banks of the stack storage. The stack pointer circuit operates in response to decoding signals from an instruction decoder which decodes a current instruction to determine whether a one-word or a multi-word stack operation is desired.

Abstract: An optical pickup apparatus (10) for reading data from a plurality of tracks of an optical disc (34) at the same time by focussing spots (M, . . . ) of each light beam on a plurality of tracks, passing the reflected light beams of spots (M, . . . ) sequentially through an objective lens (30), a collimator lens (28), and a focus adjusting lens (50) in this order, and detecting the reflected light beams with photodiodes (52M, . . . ) disposed along a photodiode light reception plane (68). In order to make each reflected light become incident upon each photodiode (52M, . . . ), a case (72) and a bracket (78) are separated from a chassis (70), and support the focus adjusting lens (50) and the photodiodes (52M, . . . ) respectively. The case (72) and bracket (78) are made so that they can be fixed to the chassis (70) at optional positions in a predetermined area along a direction of the optical axis (66).

Abstract: An optical disc storing a copyrighted digital product has a data area in which N processed parts are provided in order to certify that the stored digital product is an original one. A BCA provided on the optical disc stores judgment criteria information as well as N pieces of physical feature information. The judgment criteria information includes a numeric value N being the total number of processed parts, and a numeric value M being an integer between 0 and N inclusive and representing the security level to be assured for the digital data stored. When a numeric value P being the total number of processed parts in a normal state exceeds the numeric value M, a reproduction device reproduces the optical disc. When the numeric value P falls short of the numeric value M, the reproduction device does not reproduce the optical disc.

Abstract: An information recording medium is provided with a wobbled track, wherein at least a part of the track is subjected to wobbling based on a wobble signal in which at least a part of recording information is randomized. Each track is wobbled at a randomized frequency, so that a frequency of a wobbling signal obtained from the wobbled track is randomized. As a result, the influence of crosstalk between adjacent track is reduced.

Abstract: Disclosed are an information recording method and an optical disk unit that maintain a good jitter even when a line velocity is variable in a mark edge system. In the case where an erasing power when erasing a record mark at a linear velocity v1 is Pe1(mW), a recording power when forming the record mark at the linear velocity v1 is Pw1(mW), an erasing power when erasing the record mark at a linear velocity v2 faster than v1 is Pe2(mW), and a power when forming the record mark at the linear velocity v2 is Pw2(mW), a relationship of Pw1/Pe1>Pw2/Pe2 is satisfied.

Abstract: A predetermined synchronization pattern (40), a so-called VFO field, in, for example, the headers 3 of an information carrier. The predetermined synchronization pattern contains a first part with marks having a first length of (d+1) times the channel bit length, and spaces having a second length of (d+1) times the channel bit length, and a second part with marks having a third length of (k+1) times the channel bit length and spaces having a fourth length of (k+1) times the channel bit length and a third part, which third part contains marks having a length of (k?d) times the channel bit length and spaces having a length of (k?d) times the channel bit length. This sequence of patterns is advantageous for setting the dynamic range of an Automatic Gain Controlled (AGC) amplifier located within a device reading the information carrier.