Abstract: The present invention discloses a method for determining disc type. Perform a focus servo process by emitting a light beam with a specific wavelength and a focus error signal is generated. According to the overshooting value after the focus error signal forming an S curve, the disc type is determined.

Abstract: An optical disk apparatus capable of determining the type of a loaded optical disk. In accordance with an RF signal output from a pickup, an RF processing section of the optical disk apparatus generates a focus signal (an FOK signal), which is an envelope of the RF signal, and supplies the focus signal to a DSP. In the DSP, the level of the FOK signal is compared with a threshold value, and a result of comparison is supplied to a controller. The controller determines occurrence of defocus on the basis of the comparison result. Concurrently, the controller quantitatively evaluates the level of the FOK signal by means of sequentially changing the threshold value, thereby determining the type of the optical disk on the basis of the reflectivity of the optical disk.

Abstract: A method is provided for performing data-writing or data-reading with an optical data storage medium including a substrate. The method includes the following steps. The storage medium is irradiated with light from a light source via an objective lens, so that a light spot is formed on the storage medium. Then, the lens is moved from the focus point to a predetermined defocus point where the light spot has a maximum peak intensity. The defocus point is detected as a minimum depletion point regarding the aberration caused by a thickness error of the substrate.

Abstract: A method for discriminating a type of an optical recording medium including the steps of: checking a disk is mounted; performing a focus-searching by rotating a mounted disk by means of a recording/reproducing system for a specific disk to detect a focus search level, and identifying whether the currently mounted disk belongs to a specific type on the basis of the detected focus-search level; detecting an RF level and/or a focus error signal level by rotating the mounted disk, and identifying a type of the currently mounted disk on the basis of the detected signal.

Abstract: A high density optical disc that can be driven changeably with the existent optical disc by the same driving apparatus. On the recording surface of the optical disc, a light transmissive layer with a thickness of about 0.2 to 0.4 mm is formed. The recording face is accessed by allowing a light beam with a wavelength of 395 to 425 nm in a spot shape to be irradiated onto it. Also, the light beam is converged in a spot shape by an objective lens having the numerical aperture of about 0.62 to 0.68.

Abstract: In an optical disc drive, signals from two satellite spots are used to cancel DC offset from a tracking error signal, and for generating a quadrature signal for determining direction of radial movement. The two satellite spots generate signals that are out of phase with the main tracking error signal by about one-fourth period.

Abstract: An apparatus and method therefor to discriminate a type of disc including a motor rotating a disc, a pickup detecting light reflected from the disc, and a system controller. The system controller performs a control process of enabling a focusing operation on the disc while stopping an operation of the motor in a disc type discrimination mode and discriminates the type of disc according to a result of detecting a time corresponding to a distance from a surface of the disc to a data recording layer of the disc using a light reflected during the focusing operation on the disc.

Abstract: A method and apparatus identifying a type of a recordable disc according to whether a land pre-pit (LPP) is formed on the disc. The apparatus includes an RF (radio frequency) amplifier amplifying light reflected by the disc to a predetermined value; an LPP signal detector detecting an LPP (Land Pre-Pit) signal from output signals of the RF amplifier; and a system controller identifying a type of the disc according to whether the LPP signal is detected by the LPP signal detector. Since a disc type is discriminated and operational conditions of a disc drive are adequately set during an early stage of a disc driving period, a lead-in time of a disc can be reduced.

Abstract: An optical disc recorder and/or player using as a recording medium an optical disc having a plurality of recording layers formed one over another includes an optical pickup having a photodetector to direct a light beam towards any one of the plurality of recording layers and detect a return light beam from a recording layer, and an identifier to compare an output signal from the photodetector with a predetermined reference value and identify, based on a comparison result, which one of the plurality of recording layers formed in the optical disc has focused thereon the light beam from the optical pickup.

Abstract: A boundary crossing detector in a tracking and focus servo system of an optical disk drive is presented. A tracking error signal can be monitored as an optical pick-up unit of the optical disk drive is allowed to move across an optical media in the optical disk drive. If a peak-to-peak value of the tracking error signal changes by a threshold value, than the boundary crossing can be indicated.

Abstract: An apparatus and method detecting a fashion disc, which can detect fashion discs having various shapes as well as standard discs having a diameter of 12 cm and prevent instability when reproducing the fashion discs. The method includes (a) detecting the size of an optical disc inserted in an optical disc drive by sensing the weight of the optical disc and driving the optical disc drive; (b) determining the size of the optical disc by detecting an amount of data recorded on the optical disc from a lead-in area of the optical disc; (c) if the amount of data recorded on the optical disc is below a reference value, moving a pickup to a periphery area and measuring a focus error; and (d) if the measured focus error is above a constant value, detecting the optical disc as a certain optical disc and limiting the operational speed level of the optical disc drive.

Abstract: A method of detecting a servo error, an apparatus therefor, a disk which maintains quantity of a servo error signal, a method of controlling a servo of an apparatus for recording data on and reproducing data from a disk, a method of detecting the tracking error, and a method of detecting tilt error of the apparatus. The apparatus for recording data on and reproducing data from the disk in which a recording area is divided into sectors, each sector has a header for indicating an address, each header has a first header and a second header which are recorded to deviate from the center of the track in opposite directions, and the first header and the second header have address areas in which the addresses of sectors are recorded and synchronous signal areas in which synchronous signals for detecting the address signals recorded in the address area are recorded.

Abstract: The track jumping of a scanner (1) on optical storage media in which information items are stored on groove and land tracks or which have not yet been written to is intended to be made possible in a reliable manner. For this purpose, firstly a fictitious track type is defined for a regulating circuit (1, 2, 7, 8, 9, 10), which regulates the position of the scanner (1). The regulating circuit (1, 2, 7, 8, 9, 10) is then closed on the basis of the track type defined and a track scanning signal. The reaction of the scanner (1) to the closing is detected in order to obtain from this an item of information about the track type. This method is also advantageous, in principle, for closing the track following regulation in information carriers having relatively high storage densities.

Abstract: A circuit for recovering the timing reference signal includes a superheterodyne phase locked loop. The recovery circuit avoids the need for a phase linear filter with a large percentage bandwidth and allows placement of the filter at a point in the recovery circuit where the center frequency to be passed is substantially fixed. The recovery circuit thus constructed further allows the bandwidth of the filter to be narrower and tailored to match the modulation characteristics of the timing recovery signal. This further results in a better signal-to-noise ratio into a limiter and phase detector, improving the performance of the phase locked loop.

Abstract: An optical disc system for efficiently controlling a sled motor is provided. The optical disc system has a sled motor for moving an optical pick-up; a digital servo core to generate a first and a second sled control signal; a microcomputer for generating a selecting signal, a third and a fourth sled control signal for controlling the sled motor; a first and a second selecting unit for receiving the selecting signal and selecting and outputting one of the first and third sled control signals and selecting and outputting one of the second and fourth sled control signals, respectively; and a third and a fourth selecting unit for respectively receiving the outputs of a first and second digital-to-analog converters and generating the respective outputs of the first and second digital-to-analog converters in response to the selecting signal to the sled motor.

Abstract: In a focus control of an optical disk with a fast reproduction velocity and a large face deflection, the present invention can effect a mistakeless and reliable focus pull-in method. The present invention comprises: means for applying a braking signal to a focus actuator before closing a focus control loop; means for detecting a reversal of a relative velocity between an objective lens performing a focus search operation and an optical disk which effects an up-and-down motion due to the face deflection; and means for detecting the relative velocity between the objective lens and the optical disk from a focus error signal which is detected in each layer of a multi-layer disk.

Abstract: An optical disc is described for recording data, which disc has a recording area for recording data encoded in optical marks at a recording density. The recording area has circular or spiral tracks provided with a servopattern comprising headers alternating with track portions. The headers contain position information encoded in preformed marks. The track portions comprise periodic characteristics, e.g. a wobble, to synchronise the data writing and reading operations. For reliably detecting the headers the phase of the periodic characteristics comprises a phase jump at a predetermined distance before each header.

Abstract: A method and device for determining the presence or absence of a disk and/or a disk size without using FG signals, are provided. The method includes placing a pickup at a first zone on the optical recording medium, the first zone located between an outer radius of a first recording medium type and an outer radius of a second recording medium type, where the outer radius of the second recording medium type is larger than the outer radius of the first recording medium type; detecting a reflected signal based on a returned beam from the first zone of the optical recording medium; and determining at least one of a size and an absence of the optical recording medium based on the detected reflected signal. Therefore, an FG sensor that is provided in a general disk device can be eliminated, thereby reducing the size and cost of a disk device.

Abstract: The present invention measures first and second detection signals respectively obtained at two focuses during a focus search(by means of an optical head 2. Then, a type of a disk-shaped optical record medium is determined by a microcomputer in a system controller 7, from a comparison between characteristics of the first and second measured detection signals. Moreover, the present invention can measure an amplitude and a frequency of the detection signal obtained at the focus during the focus search to thereby determine the type of the disk by using the measured result. After the parameters are set in accordance with the determined result, the focus servo control is turned on.

Abstract: The present invention measures first and second detection signals respectively obtained at two focuses during a focus search by means of an optical head 2. Then, a type of a disk-shaped optical record medium is determined by a microcomputer in a system controller 7, from a comparison between characteristics of the first and second measured detection signals. Moreover, the present invention can measure an amplitude and a frequency of the detection signal obtained at the focus during the focus search to thereby determine the type of the disk by using the measured result. After the parameters are set in accordance with the determined result, the focus servo control is turned on.

Abstract: An optical disc discriminating system comprises: a tracking error signal generating means adapted to generate a tracking error signal whose amplitude level varies with a groove depth of information tracks on an optical disc; a tracking servo means for directing a laser beam along an information track on the optical disc in accordance with the tracking error signal; a comparator adapted to compare the amplitude level of the tracking error signal supplied from the tracking error signal generating means with a reference level, with a tracking servo loop of the tracking servo means in an opened condition; a discriminating means adapted to discriminate the first and second groups of optical discs in accordance with a result from the comparator.

Abstract: A method of detecting the type of optical disc inserted in an optical disc player including the steps of: i) attempting to focus a laser read head on the disc using a first set of player parameters appropriate for a first type of disc; ii) if focus is obtained: a) reading data from the disc and determining whether a sub-code representative of a second type of disc is present; b) if so changing the first set of player parameters to a second set of player parameters appropriate to a second type of disc; c) if not playing or indicating the presence of the first type of disc; iii) if focus is not obtained changing the first set of player parameters to the second set of player parameters; iv) if focus is then found playing or indicating the presence of the second type of disc.

Abstract: Disclosed is an apparatus for recording and playback data into and from an optical disc having: first tracks including a wobbled track and a non-wobbled track each implemented by either a land or a groove; and second tracks each sandwiched by the first tracks and used for recording information wherein if the first track is implemented by a groove, the second track is implemented by a land and if the first track is implemented by a land, the second track is implemented by a groove. The apparatus includes a unit for radiating a beam to a particular track on the disc; a unit for detecting a beam reflected by the particular track on the disc; and a unit for controlling the radiation unit so as to have the radiation unit trace a wobbled track adjacent to the particular track in accordance with the reflected beam. The apparatus is capable of generating a tracking-error signal by using only 1 beam.

Abstract: There is disclosed an optical disk apparatus to which a CD, DVD, and extra high density optical disk capable of recording/reproducing an information signal with a density higher than that of the CD or DVD are selectively attachable. The attached optical disk is irradiated with a laser beam for the CD from an optical pickup for the CD/DVD. A focus error signal is detected based on a return light from a signal surface, and the attached optical disk is judged to be the extra high density optical disk when an amplitude of the focus error signal is not more than a predetermined value. When the attached optical disk is judged to be the CD or DVD, a tracking error signal is detected based on the return light from the signal surface. When the amplitude of the tracking error signal is not less than another predetermined value, the attached optical disk is judged to be the CD.

Abstract: A disc has a physical factor changing a shape or a reflection coefficient in a tangential direction of a record track.

Abstract: A disc type determining apparatus in a disc recording and reproducing apparatus in which vibrations generated by rotations of a disc occur in a focus and tracking control actuator includes an error gain adjusting unit, which adjusts an amplitude of a focus and tracking error in order to maintain a constant amplitude of the focus and tracking error; a loop gain adjusting unit which compares the closed loop phase of the focus and tracking control loop and a predetermined reference closed loop phase, and maintains a constant gain of the focus and tracking control loop; a vibration measuring unit which measures vibrations using the adjusted error and the output of a controller; and a disc type determining unit which extracts a predetermined signal to determine the type of a disc using the measured vibrations, measures the deflection, eccentricity, and mass eccentricity of a disc using the extracted signal.

Abstract: A method is provided for performing data-writing or data-reading with an optical data storage medium including a substrate. The method includes the following steps. The storage medium is irradiated with light from a light source via an objective lens, so that a light spot is formed on the storage medium. Then, the lens is moved from the focus point to a predetermined defocus point where the light spot has a maximum peak intensity. The defocus point is detected as a minimum depletion point regarding the aberration caused by a thickness error of the substrate.

Abstract: In a recording medium which is circular and has first and second recording layers, the first and second recording layers each include one or more first tracks extending concentrically or spirally and one or more second tracks extending concentrically or spirally, each of the one or more first tracks and the one or more second tracks includes a plurality of first sectors and a plurality of second sectors, each of the plurality of first sectors includes first and second regions, each of the plurality of second sectors includes third and fourth regions, first and second grooves are formed in each of the second and fourth regions, the first and second grooves extending concentrically or spirally and oscillating sinusoidally, oscillation of the first groove has a first oscillation characteristic at a first prescribed position in the second region, oscillation of the second groove has a second oscillation characteristic at a second prescribed position in the fourth region, and the first and second oscillation chara

Abstract: An optical disc apparatus 10 which is compatible with a CD and a DVD has a configuration having: an optical pickup 13 which performs a scanning operation in a focus-on and track-off state to read signals from an optical disc 11; an RF amplifier 15 which, on the basis of the read signals, produces binary track-cross signals and binary mirror signals; a first edge counter 17 which counts the number of the binary track-cross signals; a second edge counter 18 which counts the number of the binary mirror signals; and a CPU 19 which discriminates between a CD or a DVD on the basis of a ratio between the number of the binary track-cross signals and the number of the binary mirror signals.

Abstract: Wobbles or a wobbling characteristic (manner, shape, configuration) of a groove track formed on a recording disc represents a type of the recording disc. Therefore, a master disc used for manufacturing such recording discs can be prepared in an easy manner.

Abstract: A recording apparatus, a recording method, and a recording medium, which allows a search operation based on a second segment information signal representing finely divided segments of a recording signal even in a player which can perform only a searching operation of a first segment information signal representing large segments of the recording signal. When a change of the second segment information signal of a signal to be recorded is detected, the first segment information signal being formed is updated and the first segment information signal is recorded together with an audio signal. That is, the second segment information signal of the signal to be recorded is converted into the first segment information signal and recorded together with the audio signal.

Abstract: An objective lens of an optical pickup is made to move from far position to near position with respect to DVD with constant speed, and a timer counts time taken for the movement of a focus of a laser beam between recording layers of the DVD on the basis of a focus error signal obtained from this movement. In the case of the DVD of the single-layer, since the recording layer is one-layer, and there is no interlayer, count value becomes small value. While, in the case of DVD of the multi-layer, the recording layer consists of a plurality of layers, thus one or plural-interlayer exists, therefore, count value becomes large value. Accordingly, if small count value is obtained, its DVD is discriminated as DVD of the single-layer. While, if large count value is obtained, its DVD is discriminated as DVD of the multi-layer.

Abstract: A method of identifying a type of optical disc, and more particularly, to a method of identifying a type of optical disc as a single-layer disc or a dual-layer disc, in which levels of high-frequency signals reflected from the optical disc are compared with reference values set according to the characteristics of the optical disc. The method of identifying the type of optical disc includes detecting a level of a predetermined first high-frequency signal from the optical disc and setting a predetermined reference value, detecting a level of a predetermined second high-frequency signal which is generated differently according to the type of the optical disc, and comparing the reference value with the level of a second high-frequency signal and identifying the type of the optical disc. The levels of high-frequency signals are compared with a reference value, and thus the optical disc is identified.

Abstract: Light emitted from a semiconductor laser is separated by a diffractive optical element into a main beam, first sub beams, and second sub beams. The distribution of the intensity of each of the first sub beams is the same as the distribution of the intensity of the main beam. The distribution of the intensity of each of the second sub beams is different from the distribution of the intensity of the main beam. The sum of the focusing error signals relating to the main beam and the first sub beams is a final focusing error signal. The difference between the tracking error signal relating to the main beam and the tracking error signal of each of the first sub beam is a final tracking error signal. The deviation of the thickness of the substrate of the disk and the radial tilt thereof are detected on the basis of the deviation of the zero crossing points of the focusing error signal and the tracking error signal relating to the main beam and each of the second sub beams.

Abstract: A laser beam is focused at positions on an optical axis of the optical pickup by a focusing device, corresponding to kinds of the discs which are different in thickness. The focusing device is moved along the optical axis. A photodetector is provided for receiving a laser beam reflected from the disc and for producing a focus error signal. A detector is provided for detecting the difference between the focus error signals, caused by the difference in thickness of the discs and the difference in focal point of the laser beam, thereby discriminating the kind of the disc.

Abstract: According to the present invention, it is possible to accurately start an optical disc apparatus and to reduce a startup time therefor, and it is possible to securely and accurately reproduce/record information with respect to a plurality of types of optical discs in accordance with the type. According to the present invention, by calculating a threshold value of quantity of reflected light for discriminating the type of optical disc on a basis of a measured value of quantity of reflected light from an optical disc of high reflectivity such as CD-ROM and CD-R and a measured value of quantity of reflected light from an optical disc of low reflectivity such as CD-RW to update the threshold value, the type of the optical disc loaded into the optical disc apparatus is discriminated securely and in short time.

Abstract: In a disc apparatus, a tracking error signal from an optical pickup is outputted to a micro-computer. The micro-computer discriminates a disc that is different in bit density (track pitch) based on amplitude and/or waveform of the tracking error signal.

Abstract: The invention relates to a disc discriminating method and an optical disc information reproducing apparatus wherein DVD-RAM which is DVD-RAM1 or DVD-RAM2 and DVDRW which is DVD-RW or DVD+RW which cannot be respectively determined based upon distance from the surface of a disc to the recording face, the number of recording faces and the reflectance can be discriminated. In case an optical disc is DVD-RAM or DVDRW, the amplitude of a push-pull tracking error signal is measured by a microcomputer in a state in which servo control is executed based upon a focus error signal. Determination is performed based upon the amplitude of the push-pull tracking error signal, when the amplitude of the push-pull tracking error signal is larger than a predetermined value, the optical disc is judged as DVD-RAM and when the amplitude is smaller than the predetermined value, the optical disc is judged as DVDRW.

Abstract: A disc discriminator of an optical disc player system is disclosed. The disc discriminator has a 4-split photo-detector for converting the beam concentrated by the optical pickup unit into an electric signal by means of a plurality of photo diodes divided into first through fourth quadrants. A push-pull signal generator is provided for amplifying a difference between signals generated from two pairs of photo diodes which are symmetrical in the upper and lower sides from the center of a track direction, and generating a push-pull signal. A comparator compares the push-pull signal generated from the push-pull signal generator with a predetermined reference voltage, and generates a digital video disc/compact disc discrimination signal discriminating between a digital video disc having the thickness of 0.6 mm and a compact disc having the thickness of 1.2 mm.

Abstract: An optical disk playing apparatus which performs at least a focusing servo operation for reading light as a servo operation and irradiates the reading light onto one optical disk, receives reflected light from the optical disk by a pickup to obtains a light receiving signal, moves an irradiated position of the reading light onto the optical disk to cross tracks on the disk; generates a tracking error signal in response to the reading signal during the track crossing; compares the tracking error signal with a threshold value; and determines the type of the optical disk in accordance with the number of pulses in the compared result signal within a predetermined period from start of the track crossing.

Abstract: A boundary crossing detector in a tracking and focus servo system of an optical disk drive is presented. A tracking error signal can be monitored as an optical pick-up unit of the optical disk drive is allowed to move across an optical media in the optical disk drive. If a peak-to-peak value of the tracking error signal changes by a threshold value, than the boundary crossing can be indicated.

Abstract: A media type detector in a tracking and focus servo system is presented. Operating parameters for a first media type are loaded and a peak-to-peak value of a tracking error signal is calculated. Whether the media type is the first media or a second media can then be determined by comparing the peak-to-peak value with a threshold value.

Abstract: A head load algorithm for an optical disk drive is presented. On startup, the optical media can be spun up. Then an optical pick-up unit can be positioned at an extreme position, for example at the inner diameter, and focus can be closed. The optical pick-up unit then can be incrementally moved away from the extreme position while the tracking error signal is monitored to locate an area of the optical media with tracks. Once the area is located, a tracking servo system can close on one of the tracks.

Abstract: Optical disks compliant with different standards are recorded or reproduced by a single recording/reproducing apparatus by a first step of determining a substrate thickness of the disk based on a focusing error signal, when a focusing section for bringing the light beam into a focus on the disk is moved in such a way as to approach or withdraw from the recording surface of the disk; a second step of performing any one step of determining the number of recording surfaces of the disk when the focusing section is moved in such a way as to approach or withdraw from the recording surface of the disk, and determining whether or not the disk can be recorded and reproduced using a tracking error signal detected when the light beam crosses the track.

Abstract: In order to reproduce signals from a double-layer optical disc having two signal recording surfaces, a focus jump that the focusing of an objective lens from the one signal recording surface to the other signal recording surface is quickly achieved, is necessary. When a focus error signal (FE) from a pickup (60, 70) reaches a predetermined threshold value (Vcomp), a deceleration signal for decelerating the objective lens (42) is supplied to an actuator (47). Preferably, a deceleration pulse voltage is lowered step by step. The deceleration pulse voltage is determined in accordance with the maximum value (DFEmax) of a differential focus error signal (DFE) generated by differentiating the focus error signal (FE). Preferably, the address seeking is done simultaneously with the focus jump. The focus jump is performed in accordance with the layertolayer distance which is measured beforehand. The focus jump is performed by using a lens (143) having a controllable focal distance.

Abstract: The invention detects the thickness error of the transparent substrate using a general focus error signal detection system employing the fact that the reflecting light from the optical disk causes distortions in diffraction image at the detection plane or unsymmetrical expansions before and after the detection plane due to spherical aberration as a result of thickness errors of the transparent substrate. The absolute amount of the thickness error of the transparent substrate and its symbol are detected by detecting the difference between the absolute value of the positive side peak and the absolute value of the negative side peak of the focus sum signal, or the difference in focus positions between the peak point of the focus sum signals and the zero point of the focus error signals using the focus error signal detection system according to the knife-edge method. This enables it to detect the thickness error of the transparent substrate without using a special optical system.

Abstract: In an optical disk apparatus, a sensitivity adjusting circuit measures a time between a reflection on a surface and a reflection on a recoding layer of an optical disk when moving an objective lens. This time is considered to be in accordance with sensitivity of an actuator during layer jumping, and thereby the magnitudes of a kick pulse and a brake pulse to be applied to the coil of the actuator is increased or decreased in accordance with the time between the reflection on the surface and the reflection on the recording layer. Thereby, the sensitivity dispersion of the actuator of the optical pickup is adjusted.

Abstract: An optical head used for recording/reproducing information signals for an optical disc having a light transmitting layer on a recording layer includes an actuator for the collimator lens. A collimator lens arranged between a light source and an objective lens is moved by the actuator for the collimator lens in a direction of cancelling the spherical aberration ascribable to thickness errors in the light transmitting layer. By this structure, the amount of generation of spherical aberration is reduced even if the numerical aperture NA of the objective lens loaded on the optical head is increased to render it possible to increase the recording capacity of the optical disc.

Abstract: The frequency components of the groove wobbles of disks are extracted from push-pull signals SPP by first and second filters in a wobble detecting section. The wobble detecting section supplies to the controller the detection levels of the frequency components. The controller identifies the kind of the mounted optical disks based on the detection levels.

Abstract: A signal generation method capable of generating a cross track signal having a predetermined phase difference from a tracking error signal even in a land and groove recording method in which a land width and a groove width are made equal, wherein a main spot is detected at a split photodetector, a first side spot is detected at a split photodetector, and a second side spot is detected at a split photodetector; a first error is calculated as an error of the optical disk in a radial direction from four detection signals detected at the photodetector, a second error is calculated as the error of two detection signals of the photodetector, a third error is calculated as the error of two detection signals of the third photodetector, and the sum of the second and third errors is subtracted from the first error to calculate a tracking error signal; and a difference between the second error and the third error is found to calculate a cross track signal having a phase shifted by 90° from the tracking error signal