Abstract: In an optical recording medium having a track including plural pits formed based on first data to be recorded and lands defined between neighboring pits, these pits are recorded as they are deformed based on the second data. The first and second data are synthesized and reproduced to realize audio reproduction with a broad frequency range. Moreover, the first data are adapted to be reproducible by a customary disc reproduction device. The reproduction of the first data is controlled by the second data to protect recorded data.

Abstract: In a disk-shaped recording medium such as an optical disk and the like, a reference clock with a frequency corresponding to a reproduction frequency of data reproduced from a data recording region is divided in accordance with a ratio between a record density of a header region where pre-formatted data including a sector mark for indicating a leading position of a sector is recorded, and a recording density of a data recording region subsequent to the header region, so as to produce a sampling clock. By use of thus-produced sampling clock, the sector mark is detected. Even if the header region has a recording density different from the recording density of the data region, to use a sector mark detector having the same structure as of a sector mark detector which is employed in the case where the header region has the same recording density as that of the data region.

Abstract: An information recording medium and an information reproduction apparatus that can substantially increase the capacity for recorded information. A preformat pit array 202 exists on the extension of the boundary between a concave portion 103 and a convex portion 104 and includes information on both sectors across the boundary. An adjustment pit array 201 precedes the preformat pit array 202 in the advancing direction of light that reproduces information recorded on an information recording medium. The information reproduction apparatus adjusts the amplifying rate so that the level of a signal from the adjustment pit array 201 becomes equal to a reference level required to reproduce the information correctly. The apparatus then uses this amplifying rate to correctly reproduce the information in the preformat pit array 202.

Abstract: To improve a tilt detection sensitivity and to detect a tangential tilt of recordable and rewritable optical recording media where no signal is recorded previously, An optical head assembly includes a semiconductor laser 6, an objective lens 5 which focuses a laser beam onto a disk D, and a photodetector 9 adapted to receive reflected light from the disk D.

Abstract: Audio data of 20 bits is separated into first data of upper 16 bits and second data of lower 4 bits. EFM modulation data is formed from the first data. A laser beam is on/off controlled in correspondence to the logic level of channel data obtained by NRZI modulating a serial data train. The first data, therefore, is recorded in a manner similar to the case of a compact disc. Each pit is controlled so as to have a displacement in the right/left direction for the track center in accordance with the second data and the deviated pit is formed. When data is recorded by the displacement of the pit, since a high frequency component of a tracking error signal changes upon reproduction, the second data can be extracted from the tracking error signal.

Abstract: An optical system of an optical pick-up that is capable of using thin cover type and thick cover type optical discs. The system includes a light source portion for emitting a short wavelength laser beam for the thin cover type optical disc and a long wavelength laser beam for the thick cover type optical disc, and an objective lens for converging the laser beam onto an information layer of the optical disc through the cover layer. The objective lens has a diffractive lens structure having wavelength dependence such that spherical aberration varies in the overcorrected direction as incident wavelength increases. The light source portion emits the laser beam such that divergence of the long wavelength laser beam incident on the objective lens is larger than that of the short wavelength laser beam. The objective lens converges the laser beams of an identical diffractive order without changing position thereof.

Abstract: A method for multi-track optical data recording comprising the steps of providing an optical recording medium that includes a plurality of parallel, preformatted guide tracks, with sufficient space between adjacent guide tracks for recording a plurality of data tracks; providing relative motion between the optical recording medium and an optical head in a direction generally parallel to the guide tracks; imaging a guide track onto a detector array disposed relative to the optical recording medium; and generating a first tracking error signal representing the cross-track displacement of the guide track relative to the optical head. The method further comprises driving a closed-loop servo system to reduce the residual tracking runout of the guide track and simultaneously recording a band of data tracks in the unpreformatted space adjacent to the guide track and one or more control tracks parallel to the data tracks.

Abstract: When an external disturbance that causes the corrected amount of light reflected from a glass master disk 15 to surpass a threshold value T1 is applied to the control loop, not only the main control section 38 but also the sub-control section 37 controls the corrected amount 27. In this case, the influence of the external disturbance is suppressed quickly. More specifically, the control voltage of the main control section 38 is held the moment the corrected amount 27 of light reflected surpasses the threshold value T1. The sub-control section 37 controls the corrected amount 27 while the corrected amount 27 remains greater than the threshold value T1, and the sum of the control voltages of the main control section 38 and sub-control section 37 is applied to the piezoelectric element 23, thereby suppressing the influence of the external disturbance.

Abstract: An apparatus for reading from and/or writing to optical recording media on which data markings are arranged along tracks arranged next to one another. The apparatus according to the present invention comprises a light source, a focusing means and an intensity distribution converter. In the present invention, both the extent of the focus spot of the primary beam is reduced and the disadvantages occurring due to the secondary beams are reduced. In an exemplary embodiment, the intensity distribution converter comprises a filtering strip arranged in the region of the focusing means.

Abstract: A grating mounting section 10 for mounting a laser diode 3 and a diffraction grating element 8 is formed in a frame body 2 of an optical pickup device. The diffraction grating element 8 includes a main body 83 provided with a grating face 82, a holder 84 being integral with the main body 83 while surrounding the same, and an arm portion 81 protruded outward from the outer circumferential face of the holder 84 as viewed in the radial direction. The arm portion 81 is protruded outward through a groove 22 formed in the grating mounting section 10 of the frame body side. An angular position adjustment of the diffraction grating element 8 can be carried out by turning the arm portion 81 about the optical axis.

Abstract: An actuator control device is provided for performing some modifications such as making the output of a disturbance observer zero for quickly restoring the proper tracking control if the out-of-track state takes place and if the outside force exceeding the maximum force generated by an actuator is applied to the device itself. In the actuator control device, a disturbance observer estimates disturbance added to the actuator. The second control signal corresponding to the estimated disturbance is added to the first control signal. The added signal is made to be a third control signal. Further, the second control signal is stored in a storage unit. The stored value is further added to the third control signal as the fifth control signal. By performing some modifications such as making the second control signal zero according to the abnormal state, this arrangement makes it possible to quickly restore the proper tracking control even if the out-of-track state takes place.

Abstract: A recording apparatus for an erasable optical disk, which includes: a first part which measures a modulation degree of a signal reproduced from an area of the optical disk at a time of overwriting first data recorded in the area with second data; a second part which determines a first write power level corresponding to the modulation degree measured by said first part based on a relation between write power levels and modulation degrees of signals reproduced from a test recording area of the optical disk, the signals being recorded therein with the corresponding write power levels different from one another; a third part which obtains a target modulation degree corresponding to a type of and a recording rate for the optical disk from one of tables prestoring modulation degrees corresponding to optical disk types and recording rates; and a fourth part which obtains a write power level for overwriting from the first write power level based on a comparison between the target modulation degree and the modulation

Abstract: A recording and/or reproducing apparatus for an optical disc having a pit area where data has been recorded and also having a grooved area where data is to be recorded includes an optical pickup, an error signal generating unit, a shift signal generating unit and a servo controller. The optical pickup includes an objective lens for converging a light beam on a signal surface of the optical disc, a photodetector for receiving the light beam reflected from the signal surface and an actuator for moving the objective lens in a direction perpendicular to its optical axis. The shift signal generating unit is responsive to the output signal of the photodetector to generate a lens shift signal corresponding to the amount of shift of the objective lens from its neutral position. The servo controller drives the actuator based on the lens shift signal or the error signal to move the objective lens along the radial direction of the optical disc.

Abstract: Method of registering a running time on an information carrier, the information carrier comprising main data and subcode data, the running time being indicated in a subcode channel by a subcode time expressed in accordance with a predetermined format. A pseudo-running time is described by incrementing the subcode time in accordance with a pseudo-tempo, which is different from an actual tempo, the actual tempo representing a tempo in accordance with the actual running time. The invention further relates to an information carrier and an apparatus.

Abstract: The present invention provides a method for controlling a focus speed of a pick-up head while performing a layer jump operation over a multi-layer optical disk in an optical information reproducing apparatus. The optical information reproducing apparatus includes the pick-up head, an actuator and a counter. The pick-up head has an objective lens positioned over a first focus of the multi-layer optical disk and in response to a signal reflected from the multi-layer optical disk, will generate a RF level signal and. The actuator is electronically connected to the pick-up head for driving the objective lens to perform the layer jump operation in response to a kick pulse signal. The counter generates a counter value in response to the kick pulse signal.

Abstract: In a tracking controller for an optical pickup, a photodetector having four light reception parts receives return light from an optical disc and outputs light detection electric signals. Predetermined addition and subtraction operations are performed on the light detection electric signals from the light reception parts. A phase comparator compares phases and outputs a pseudo radial contrast signal. Bringing into tracking servo control is performed based on the pseudo radial contrast signal.

Abstract: The invention relates to an optical scanning device (17) for scanning an information carrier (9), such as a CD or DVD. The scanning device comprises a radiation source (31), a lens system (43) with an optical axis (45) for focussing a radiation beam (47) supplied by the radiation source into a scanning spot (55) on the information carrier, and a focussing actuator (65) for displacing the lens system with respect to a base part (29) of the scanning device in a direction parallel to the optical axis. The lens system is elastically suspended with respect to a suspension member (63) of the scanning device, said suspension member being arranged next to the lens system, viewed in a direction transverse to the optical axis.

Abstract: An optical disc having a power calibration area for calibrating the power of a data recording laser beam. The power calibration area is provided at an inner peripheral part of the disc and has test areas and count areas. The test areas are provided to accomplish trial writing of data, and the count areas are provided to record data representing the use condition of the test areas. Data is recorded on the optical disc, while calibrating the data recording laser beam. The number of the test areas is increased in accordance with an increase in the recording density of the optical disc. The optical disc may be a double-density CD. In this case, the disc has 800 to 1200 test areas. The test areas have the smallest possible size, and the count areas are provided in the smallest possible number. Therefore, the disc can have sufficiently large data regions. Thus, the power of the data recording laser beam can be therefore adjusted many times.

Abstract: The disclosed invention relates to an optical integrated device, an optical pickup, and an optical disk apparatus, and is applicable to an optical disk apparatus for playing back a compact disk (CD) and a DVD (Digital Video Disk), thereby to access a plurality of types of optical disks with a simple arrangement. For dividing feedback light with a hologram 19A and detecting the divided feedback light with a light-detecting element 20, laser sources 15A, 15B having different wavelengths are spaced a predetermined distance D from each other in order to compensate for the difference between the diffraction angles &thgr;A1, &thgr;B of the hologram 19A.

Abstract: On an optical disc including a substrate on which pits having at least two different depths are formed, main information is recorded by the shape of the pits and additional information is recorded by the depth of the pit. It is possible to reverse polarity of a tangential push-pull signal dependent on the depth of the pit, and therefore it becomes possible to record information utilizing the depth of the pit. This improves recording density of the optical disc. Further, when information of the optical disc is to be copied, the information recorded by the depth of the pit cannot be copied. Therefore, unauthorized reproduction can be prevented.