Abstract: A polarizing beam splitter for separating an upstream beam from a downstream beam according to the polarization of an incident beam is provided between first and second light sources emitting laser beams at respective wavelength and an objective lens. A phase plate for providing a phase difference to a beam incident on the polarizing beam splitter is provided between the polarizing beam splitter and the light sources. A portion of the laser beam incident on the polarizing beam splitter is reflected by the polarizing beam splitter and caused to be incident on a photo-detecting unit, so as to prevent an unnecessary portion of the laser beam is incident on the photo-detecting unit. According to the invention, the laser beam is used efficiently and the cost of fabricating an optical disk apparatus is reduced by eliminating a need for a gain controlling circuit in the photo-detecting unit.

Abstract: An information playback apparatus is provided to obtain editing effects using an optical disc in the same sense as an analog record disc is manipulated. An audio editing apparatus for playing back an optical disc such as a CD is provided with a rotatable jog dial, detecting device for detecting the amount of rotation of the jog dial, and sensing device for sensing the presence or absence of a pressing force on the jog dial. When the jog dial is rotated while being depressed with a predetermined pressing force, processing for providing sound effects is performed on the playback data to be played back from the optical disc in response to the amount of rotation detected by the detecting device. It is thereby possible to provide the same feeling of operation as provided by rotating an analog record disc through hand operations to produce playback sounds.

Abstract: An information storage medium according to an aspect of this invention comprises a rewritable area, the rewritable area comprises a user area to store user data, and a defect management area to store defect management information used to manage defective areas on the rewritable area, the defect management area comprises first and second defect management reserved areas, the first defect management reserved area being used to store the defect management information in an initial state, and the second defect management reserved area being used to store the defect management information which is transited at a predetermined timing.

Abstract: First data representing user data and third data use the same error correction codes. The first data has a first error correction block structure and the third data has a second error correction block structure. That is to say, the first data and the third data have their respective error correction block structures proper for them. In particular, the recording density of the third data is made less dense than the recording density of the first data, and the number of correction codes in the first error-correction block is set at a multiple of m whereas the number of correction codes in the second error-correction block is set at n/m times the number of correction codes in the first error-correction block so that a data-piece count in the second error-correction block is also n/m times a data-piece count in the first error-correction block. As a result, it is possible to provide a good technique of recording shipping-time information onto a high-recording-density disc.

Abstract: An optical disc and a method of making the same are provided in which the tracks on the disc are not numbered in strict numeric sequence. For example, a disc may contain only odd or only even numbered tracks, or tracks numbered 11 to 20. This is accomplished by providing invisible tracks in the positions of the tracks missing from the listing. Invisible tracks are of minimal length such that the invisible tracks are counted by a disc playing device, but will seem to a listener to be missing when the device plays the disc.

Abstract: A header of a nano storing apparatus is disclosed. If some cantilevers of the header are defective, an additional extra cantilever array is substitutively used. The header of a nano storing apparatus including: a cantilevery array including cantilevers each having a probe that is able to read and write information of the ‘n’ number of rows and the ‘m’ number of columns, an X-redundancy cantilever array to be used as a substitute when cantilever probes of a specific row in the cantilever array are defective; a Y-redundancy cantilever array to be used as a substitute when cantilever probes of a specific column in the cantilever array are defective; and a header controller for controlling each part.

Abstract: The optical disc drive reads and/or writes data from/on an optical disc having an information storage layer. In an optical disc drive 100, light from a light source 3 is focused by a focusing section 1, and each of the peripheral and non-peripheral part of light reflected by the information storage layer is received by a photodetector 4. Then, for each part of light, the drive 100 generates a focus signal and a light quantity signal, and normalizes the focus signal based on the light quantity signal. As a result, it is possible to generate a spherical aberration signal according to a quantity of spherical aberration produced at the focusing position of the light. Hence, the signal is not affected by defocusing and thus it is possible to precisely detect a spherical aberration caused by an uneven thickness of the disc and to detect a spherical aberration with high accuracy.

Abstract: In an optical disk medium, land recording tracks (1) are coupled by first and second coupling portions (3 and 4) at a particular radial position to form a tilt detecting mark SM.

Abstract: In a rewritable compact disc having a wobble groove on a substrate, crystal and amorphous states of a phase-change recording layer are an unrecorded/erased state and a recorded state, respectively. When the recording layer is exposed to recording light, amorphous marks assuming the recorded state are formed. At any of 2-, 4- and 8-times velocities with respect to a reference velocity (1-times velocity) whose linear velocity is 1.2-1.4 m/s, modulation m11 of a recorded signal when the recording light of approximately 780 nm in wavelength irradiates the recording layer via an optical system with NA=0.5 or 0.55 is 60-80%. A topmost level Rtop of reflectivity of the eye pattern of the recorded signal during retrieving at the 1-times velocity is 15-25%, and a jitter of the individual length of marks and inter-mark spaces during retrieving at 1-times velocity is 35 ns or less.

Abstract: An error correction circuit for determining an error in rotational speed of a recordable disk of a disk drive includes a sinusoidal error calculation portion adapted to generate a true oscillation error signal, and a summation portion adapted to combine the true oscillation error with a spindle error signal to generate a total error signal. The sinusoidal error calculation portion is adapted to generate a new true oscillation error based on the total error signal.

Abstract: The present invention provides CD-RW which makes high velocity recording at a level of at least 24-times velocity possible, rewritable DVD which makes high velocity recording at a level of at least 6-times velocity possible, and a recording method therefor, while maintaining interchangeability with conventional CD-RW standards and rewritable DVD standards. A rewritable optical recording medium comprising a substrate and a phase-change type recording layer, wherein a portion in a crystalline state corresponds to an unrecorded or erased state, and a portion in an amorphous state correspond to a recorded state, to record EFM modulated information by forming amorphous marks by irradiating the recording layer with a recording laser beam, and wherein recording is carried out by irradiating a recording laser beam having a wavelength of about 780 nm through an optical system having a numerical aperture NA of 0.5 or 0.

Abstract: A disk drive device capable of satisfactorily detecting address information recorded by land prepits even after data is recorded is provided. When address information recorded by land prepits is detected from a disk on which lands and grooves as recording tracks are formed and address information is recorded as land prepits on the lands, a window signal is generated by binarizing a push-pull signal (window generation circuit 31), the push-pull signal is integrated in a period based on the window signal (integration circuit 32), and the address information by the land prepits is extracted from the integrated signal (33, 34, 35, and 26).

Abstract: An optical disc drive includes an objective lens for focusing light on an optical disc with five or more stacked data storage layers and a tilt control mechanism for controlling a tilt angle defined between the optical axis of the light and a normal to the storage layers. The drive reads and/or writes data from/on a selected one of the storage layers by focusing the light on the selected layer. The numerical aperture NA of the objective lens is defined so as to fall within the range of 1.3009×D3?2.9315×D2+2.3133×D?0.0502 to 1.3009×D3?2.9315×D2+2.3133×D+0.2028, where D is a distance (mm) from a light incident side of the disc to the deepest one of the storage layers, which is located most distant from the light incident side.

Abstract: An optical disk drive includes drive current generation unit for supplying a mark forming semiconductor laser drive current and a space forming semiconductor laser drive current; first high-frequency superimposition unit for superimposing a high-frequency component on the space forming semiconductor laser drive current; and high-frequency superimposition control unit for controlling the first high-frequency superimposition unit to stop the superimposition of the high-frequency component for a predetermined duration prior to a timing at which to switch from the space forming semiconductor laser drive current to the mark forming semiconductor laser drive current, eliminating positional variations on the disk of the mark leading and trailing edges due to the high frequency superimposition.

Abstract: A plurality of types of recording pulse control rules for which the recording pulse waveform is determined according to the information signals to be recorded are stored in advance in an optical disk. When recording to the optical disk, information is recorded using a recording pulse where, due to the focused laser beam, the temperature in the recording layer cools more rapidly at a second information recording layer closer to the side where light is incident than at a first information recording layer farther away from the side where light is incident.

Abstract: A tracking error detection apparatus comprises a photodetector comprising plural photoreceptor elements; zerocross detection circuits for detecting zerocross points at which two sequences of digital signals intersect the center levels of the respective digital signals, which digital signals are generated according to the amounts of light received by the respective photoreceptor elements and are outputted from the photodetector; a phase difference detection circuit for performing phase comparison using a distance between zerocross points of the two sequences of digital signals, and outputting a result of phase comparison; and a low-pass filter for performing band restriction to a signal outputted from the phase difference detection circuit. When a phase difference between the two sequences of digital signals, which is detected by the phase difference detection circuit, is larger than a maximum value of a theoretical tracking error signal, the output from the phase difference detection circuit is limited.

Abstract: An optical recording/reproducing apparatus includes an optical pickup and a signal processor. The optical pickup includes an optical splitting device which splits light emitted from a first light source into a main light beam and sub-light beams which are symmetrical with respect to the main light beam and irradiates the split light beams on a recording medium, and a light detection device which receives the main light beam and the sub-light beams reflected by the recording medium, so as to detect a tracking error signal in a three-beam method and one of a push-pull method and an improved push-pull method.

Abstract: There is provided an optical disk drive capable of appropriately effecting recording and reproducing operations without being affected by offset values and a laser output value, which are set at startup of the disk drive, even when changes have arisen in the internal temperature of the disk drive because of changes in ambient temperature. In an optical disk drive, a temperature sensor provided on a pickup measures a temperature. When changes in temperature are greater than a predetermined level, a focus offset value, a tracking offset value, and a value of laser output from the pickup are reset.

Abstract: The present invention relates to a method of writing audio data to a rewritable recording medium as grouping the written audio data into each Audio Object Unit (AOBU). This method changes AOBU grouping criterion such as time or size if a bit rate of input audio data being written to the rewritable disk is changed, and groups written audio data into each AOBU in accordance with the changed AOBU grouping criterion while recording. As a result, an amount of management information to be created for each AOBU is reduced remarkably even if the bit rate of input audio data is relatively low.

Abstract: An optical head in which pre-formatted signals may be detected as variations in the amplitude or the phase in the pre-formatted signals are suppressed, and a recording and/or reproducing apparatus employing the optical head, are disclosed. The optical head includes a light source 212, an objective lens 220 for condensing a light beam radiated from the light source 212 on a recording track of an optical recording medium 102, and a photodetector unit 223 for receiving the light beam reflected back from said recording track. The photodetector unit 223 includes a first light receiving section 230b and a second light receiving section 230c.