Abstract: A method for checking the existence of an optical disk using a focusing signal is provided. The method in accordance with the present invention prevents misjudgement of the existence of an optical disk which is caused by noise contained in a focus error signal or by the low reflection ratio of a disk.

Abstract: The present invention provides an information storage apparatus that generates a tracking error signal based on a detection signal, and performs various control operations based on the tracking error signal. When the operation mode is a seek operation mode, the information storage apparatus generates a tracking error signal by holding the peak value of the detection signal. When the operation mode is a tracking operation mode, the information storage apparatus generates a tracking error signal directly from the detection signal. With this information storage apparatus, stable control operations can be performed, regardless of changes of conditions.

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: An optical disk apparatus for recording and reproducing data using a grove and a land of an optical disk. For data recording and reproducing using a groove, a groove focus position is used. For data recording and reproducing using a land, a land focus position is used. When shifting from a groove to a land or vice versa, a boost amount of an equalizer or power of a laser beam is temporarily increased for compensation of delay in response of a focus actuator.

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: The amount of light reflected from a disk is detected, and it is determined according to the amount of reflected light whether the disk is a recordable disk or a rewritable disk. The disk is controlled according to the result of determination such that it is rotated at a constant angular velocity (CAV) or at a constant linear velocity (CLV) and recording is executed. Further, rotation driving control of the disk is selected according to factors other than the type of the disk, such as according to whether random recording is allowed or not, according to a recording state in the disk, according to whether an alternative area is provided or not, according to a recording start position, or according to whether initialization is required or not. CLV control or CAV control is appropriately selected for a disk at recording to suppress a reduction in accessibility and a reduction in data transmission rate.

Abstract: The amount of light reflected from a disk is detected, and it is determined according to the amount of reflected light whether the disk is a recordable disk or a rewritable disk. The disk is controlled according to the result of determination such that it is rotated at a constant angular velocity (CAV) or at a constant linear velocity (CLV) and recording is executed. Further, rotation driving control of the disk is selected according to factors other than the type of the disk, such as according to whether random recording is allowed or not, according to a recording state in the disk, according to whether an alternative area is provided or not, according to a recording start position, or according to whether initialization is required or not. CLV control or CAV control is appropriately selected for a disk at recording to suppress a reduction in accessibility and a reduction in data transmission rate.

Abstract: A tracking control method measures an optimum offset by measuring a light beam irradiation state of a light beam while offsetting a tracking target position of the light beam on a recording medium so that an optimum light beam irradiation state is obtained at the tracking target position, and carries out a tracking control by setting the measured optimum offset.

Abstract: An apparatus for and a method of detecting a defocus error signal. First, second and third light receiving regions of a photodetector are arranged in a radial direction of a recording medium to independently perform photoelectric conversion with respect to incident light which is reflected/diffracted by the recording medium. A subtractor subtracts a sum signal of detection signals from the first and third light receiving regions and a detection signal of the second light receiving region to output a defocus error signal, to detect defocus and/or a change in thickness of the recording medium. The defocus error signal and a push-pull tracking error signal are compared in a state in which a predetermined amount of defocus is applied to a light spot to detect a seek direction of the recording medium having a land/groove structure.

Abstract: A tilt servo control device of an apparatus for recording information on and reproducing information from an optical recording medium set in the apparatus, the apparatus comprising an optical system for leading a laser beam emitted from a light source to a recording surface of the optical recording medium and a laser beam reflected by the recording surface of the recording medium to a photo detector and a read signal generator for generating a read signal in accordance with an output signal of the photo detector. The tilt servo control device determines a type of the optical recording medium, generates a tilt drive signal so as to reduce a tilt angle at a position of the laser beam irradiating the recording surface and an optical axis of the laser beam by a method for generating a tilt drive signal corresponding to the recording medium type, and drives a tilt angle adjuster for adjusting the tilt angle in accordance with the tilt drive signal.

Abstract: An optical disc apparatus which is compatible with a compact disc (CD) and a Digital Versatile Disc (DVD) has a configuration of an optical pickup which performs a scanning operation in a focus-on and track-off state to read signals from an optical disc; an RF amplifier which, on the basis of the read signals, produces binary track-cross signals and binary mirror signals; a first edge counter which counts the number of the binary track-cross signals; a second edge counter which counts the number of the binary mirror signals; and a central processing unit (CPU) 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: A tracking error signal calculating unit (221) detects a tracking error signal of light with respect to a mark recorded on a wobbled groove in a focused-on state from the light reflected back from the wobbled groove. A pull-in signal calculating unit (225) detects a total light volume signal PI of the mark, recorded on the wobbled groove, from the reflected light. A D-flipflop discriminating circuit (244) compares the phase of a binary coded version of a tracking error signal TE detected by the tracking error signal calculating unit to the phase of a binary coded version of the total light volume signal PI as detected by the pull-in signal calculating unit to discriminate the sorts of the optical discs having the same outer shape and the same optical system but differing in the UTOC recording system.

Abstract: A plurality of light receiving detectors receive a plurality of segments of a beam returning from an optical disc when a reading beam of light is radiated to the optical disc. An optical pickup assembly produces a plurality of signals from the beam segments in accordance with, for instance, optical intensities of the beam segments. A level adjusting circuit adjusts signal levels of these signals such that each of the signal levels of the signals becomes equal to a reference level. The reference level is determined from at least one of the signal levels of the received beam segments.

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: The present invention relates to an optical head device and an optical disk unit using the same. The optical head device includes a relay lens control unit to control at least one of lenses of a relay lens unit based on an output signal outputted from a first optical detector and a power control circuit to control an intensity of a light beam emits from a light source.

Abstract: A method for exposing an optical disk master includes rotating a substrate disk coated with a photoresist, focusing a beam on the photoresist for exposure through an objective lens, and exposing the photoresist so as to form tracks on the substrate disk in its circumferential direction. At this time, the beam is deflected at least temporarily by passing through a deflector. The beam is divided into a first beam and a second beam after passing through the deflector, and the first beam is focused on the photoresist. A difference between the current position and the target position of an optical path of the second beam is detected, and the deflection operation of the deflector is corrected based on the difference so that the optical path of the second beam is located at the target position. This method can improve the track pitch accuracy of an optical disk having a narrow track pitch.

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: Focusing control for maintaining a distance between an objective lens and a recording medium constant is executed using light whose wavelength is longer than that of recording light and whose detection sensitivity is better than that of the recording light, and a deviation of a focal point of the recording light is detected using reflected light which is reflected by the recording medium to thereby correct a control target position for a focusing control circuit, whereby the distance between the objective lens and the recording medium is corrected to a desirable distance throughout recording. In this manner, excellent focusing control is performed on recording light which has a low detection sensitivity and belongs to the UV range, while correcting a focusing control position for the recording light throughout recording.

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: Apparatus and method of power compensation and optical device using the same. The power compensation apparatus is used to compensate a write power of the optical device. The power compensation apparatus has a signal extraction circuit, a gain setting unit, and an adder. The signal extraction circuit is used to extract a absolute value of a portion of a servo error signal over a threshold voltage. The gain setting unit is used to generate a compensation signal using a gain thereof to adjust the absolute value of the portion of the servo error signal over the threshold voltage. The adder is used to add the compensation signal into the write power.

Abstract: A track servo control perform follow-up control of an optical beam to a track of an optical disk, and control the vibration of the optical beam due to the ID pit noise of the optical disk. The control system is comprised of a feedback control block for feedback-controlling the actuator by the track error signal from the actuator and the learning control block. Since the optical disk ID pit noise is periodic noise, the learning control block learns this, inputs the learning result to the feedback control system. The learning result is subtracted from the learning input, and the signal after subtraction is learned in order to converge the learning. Therefore even if the periodic ID pit noise is applied, this noise can be removed from the control loop and the vibration of the actuator due to periodic noise can be decreased, making a stable track follow-up operation possible.

Abstract: In a system using a pickup including a bifocal lens which is one lens having two focal points, mere judgment by the number of peaks of a focus error signal does not achieve a clear judgment of the type of an optical disc, especially whether it is a CD or a DVD. Therefore, it is required to perform a judgment based on a difference in recording density of the optical disc. According to the present invention, when detecting a tracking error by the phase difference method, a pulse width limit circuit 35 in a tracking error detecting circuit 7 provides such limitations that a pulse of a width larger than a predetermined pulse width should not appear in a pulse train of a phase error signal. Disc type judgment is then performed for discs having different recording densities, for instance, whether it is a CD or a DVD, based on the phase error signal after the pulse width limitation or that before and after the pulse width limitation.

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 method and device for recording information signals on a partly recorded writable record carrier (11), e.g. an optical disc. An information signal represents at least one information unit. The record carrier has a recording track which comprises preformed track position information indicative of locations for recording the information units. From the information signal a modulated signal is generated, and the recording track is scanned for recording the modulated signal. If recording is after and adjacent an existing recorded unit, linking information is read from an end boundary area of the existing recorded unit and used for logically generating the modulated signal. If recording is before and adjacent to an existing unit, linking information is read from a begin boundary area of the existing unit and thereafter used for logically generating the modulated signal.

Abstract: An optical pickup device includes a detection-use condenser lens for focusing a reflected light from a disk of a light emitted from a light source; a hologram element for dividing a light passed through the detection-use condenser lens into a light passed through a high numerical aperture region and a light passed through a low numerical aperture region; and a photodetector including at least a first light receiving element for detecting the laser beam which passed through the high numerical aperture region and a second light receiving element for detecting the laser beam which passes through the low numerical aperture region. Based on output signals from the first light receiving element and the second light receiving element, a focus error signal FE1 and a focus error signal FE2 are prepared respectively. According to an output value of the photodetector, a focus control is performed based on the error signal FE1 or the focus error signal FE2.

Abstract: A disc drive apparatus for recording or playing back data onto and from an optical-disc recording medium having a plurality of signal surface areas outputting detected information as reflected detection signals with different amplitudes, the disc drive apparatus including: reflected-light quantity detection means for detecting a total quantity of a light reflected by a signal surface of the optical-disc recording medium and outputting a reflected-light quantity detection signal representing the total quantity; integration means for integrating the reflected-light quantity detection signal and providing an integration output representing a result of integration of the reflected-light quantity detection signal; and identification-signal generation means for comparing the level of the reflected-light quantity detection signal with the level of the integration output used as a threshold value and for outputting an identification signal identifying a specific signal surface area among the signal surface areas as a

Abstract: The present invention provides a method for guiding a pick-up head to follow an information track. The method comprises the steps of sensing and sending notification of displacement between the pick-up head and the center of the information track, generating a first correction directly proportional to the displacement, generating from the first correction a second correction non-proportional to the displacement, generating a third correction from an amplified tracking error signal and generating a driving force proportional to the sum of the second and third corrections, driving the pick-up head to follow the information track.

Abstract: Disclosed herein are a high-density recording medium, such as a high-density optical disc and a recording and/or reproducing device therefor. At a transition area of the high-density optical disc allocated between a clamping area and an information area of the high-density optical disc is formed a step having a prescribed slope so that the high-density optical disc does not collide with an objective lens of an optical pickup provided in an optical disc device although the objective lens of the optical pickup is upwardly moved toward a recording layer of the high-density optical disc until it moves to the maximum working distance when the high-density optical disc, such as a Blu-ray disc, is improperly placed on a turntable provided in the optical disc device, e.g., when the high-density optical disc is placed upside down on the turntable. The thickness of the information area is smaller than that of the clamping area by the provision of the step at the transition area.

Abstract: A radiation detector array for radial tracking error detection and focus error detection, including a first plurality of spot detectors (100, 102, 104) for conducting multiple-spot radial tracking error detection, said first plurality of spot detectors including a first spot detector (100) arranged substantially centrally thereof. The array further includes a second spot detector (106) for conducting spot-size focus error detection in combination with said first spot detector.

Abstract: Disclosed are an optical information recording/reproducing apparatus and an optical information recording/reproducing method for simultaneously optimizing a distance between lenses constituting a two-objective lens and an offset in focus control. The apparatus includes a first electromagnetic actuator and a second electromagnetic actuator for cyclically moving a first lens and a second lens in the direction of the optical axis thereof; and a position control circuit for performing, upon focusing operation, the positional adjustment of the first lens and the second lens after start-up of focus control, on the basis of reproducing signals obtained from an optical disk at both ends of the cyclic movement of the first and second lenses by the first and second electromagnetic actuators.

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: An optical disk drive capable of detecting a surface deviation of a disk during a very short period includes an analog-to-digital converter (ADC) converting a focus error signal output from a pickup into digital data, and a central processing unit (CPU) writing an output of the ADC to a memory during one rotation of a motor according to a timing of a pulse signal output from a spindle motor. After that, the CPU reads data written to the memory and obtains a sine curve that minimizes the sum of squares of errors among data by a least square method. The CPU obtains a peak-to-peak value of the obtained sine curve and compares the peak-to-peak value to a predetermined threshold value, thereby determining the existence of the surface deviation of the disk.

Abstract: A method for adjusting a focus bias in an optical disc drive comprises the steps of: rotationally driving an optical disc in a state that only focus servo is engaged without engaging tracking servo; driving an actuator of an optical pick-up so that a laser beam projected from the optical pick-up is moved in a tracking direction to obtain an HF signal; and determining a focus bias by which a proper focusing point can be obtained based on the HF signal. The driving of the actuator is carried out by supplying an actuator drive control signal to a tracking actuator of the optical pick-up in a state that tracking servo is not engaged.

Abstract: A plurality of types of writable discs on which wobbles having a predetermined frequency containing absolute addresses and/or various pieces of information on the writable discs can be discriminated by controlling only focusing and using an amplitude of a wobble signal or a wobble PLL lock signal that has passed through a phase locked loop. Accordingly, a discrimination time can be reduced and a disc in an unrecorded state can also be discriminated.

Abstract: The invention relates to an optical scanning device (17) for scanning an information track which is present on an information carrier (9). The scanning device comprises a radiation source (31), a lens system (43) with an optical axis (45) for focusing a radiation beam (47) supplied by the radiation source into a scanning spot (55) on the information carrier, and a focusing actuator (65) for displacing the lens system relatively to a basic part (29) of the scanning device in a direction parallel to the optical axis. The actuator comprises an electric coil (69) which is arranged around the lens system and provided with a passage (95) for a radiation beam path (49) which extends in a direction perpendicular to the optical axis.

Abstract: An optical head includes an integrated unit (9) having a light-receiving portion for converting reflected light from a disc-shape recording medium (13) into an electric signal and a light source, an objective lens (11), a tracking coil (18a) for driving the objective lens (11) in a radial direction of the disc-shape recording medium (13), a focusing coil (18b) for driving the objective lens (11) in a focus direction of the disc-shape recording medium (13), a signal generation portion (102) for generating a focus error signal and a tracking error signal from the electric signal converted at the light-receiving portion, and a control portion (101) for controlling the tracking coil (18a) and the focusing coil (18b) on the basis of the focus error signal and the tracking error signal.

Abstract: A drive reads and/or writes data from/on an optical data storage medium, including first and second data storage layers stacked in this order toward the depth thereof, by radiating light through the surface. The drive includes a light source, a lens, a light detector, and a layer sensor. The light source emits the light. The lens produces a focal spot. The light detector includes at least one photodetector for receiving the light and generating a light quantity signal. The photodetector is used as a layer-sensing photodetector not receiving the light from the second data storage layer when the focal spot is located on the first data storage layer and receiving the light from the first data storage layer when the focal spot is located on the second data storage layer. The layer sensor determines, by the light quantity signal, where the focal spot is now located.

Abstract: An error signal detection apparatus for an optical recording/reproducing system including a light source emitting a light beam and an objective lens focusing the light beam to form a light spot on a recording medium, the apparatus including: a photodetecting unit dividing at least a part of the light beam passed through the objective lens after being reflected/diffracted from an information stream of the recording medium into light beam portions, and detecting the light beam portions; and a signal processor detecting phase differences between detection signals from the light beam portions to detect a tangential error signal, a defocus error signal, and/or a radial tilt error signal.

Abstract: Provided are an apparatus and method for stably generating a tracking error signal in an optical recording/reading system irrespective of a disc track pitch.

Abstract: A method and apparatus for realizing a stable focus jump operation even in a case where a waveform of an S-curve of a focus error signal fluctuates due to aberration due to fluctuation of a multilayer optical disk substrate thickness or the level of the S-curve fluctuates due to reflectance fluctuation are provided.

Abstract: A follow-up control system follows up a head of a storage device to a storage medium. A sine wave signal learning section (82) which learns sine wave signals according to follow-up error signals which are input to a feedback control system (80), and performs time lead compensation corresponding to a delay of the feedback system (80), is provided. Since the time lead compensation is used for the sine wave signal learning model which can learn at high-speed, frequency disturbance of high frequency, for which phase lag must be considered, can be a compensation target, and the present invention contributes to the improvement of follow-up accuracy of the storage device.

Abstract: A focus control process (S2), a spherical aberration correcting process (S4), and a focus offset adjusting process (S7 to S9) are performed in this order. In the focus control process, an output of a focus error signal obtained by detecting focal point displacement that occurs in a direction of an optical axis of a light beam focused through a two-element object lens is controlled so that the output becomes close to zero. In the spherical aberration correcting process, spherical aberration that occurs with respect to the light beam is corrected. In the focus offset adjusting process, offset of the focus error signal is adjusted. In this way, it is possible to provide a focal point adjusting method and an optical pickup device in which focus control can be performed stably by eliminating the offset.

Abstract: A focus error detecting apparatus and a focus error detecting method of an optical pickup in which the system is not easily influenced by track transversal noises and an optical disc thickness error and which can be used together with a 3-beam system or a DPD system. The return light from an optical disc is divided to a first optical path and a second optical path by a hologram device, a predetermined astigmatism is applied to the light on each divided optical path, the light is received and detected by a first detector and a second detector, and a focusing error signal is obtained by predetermined arithmetic operations.

Abstract: A tracking error signal calculating unit (221) detects a tracking error signal of light with respect to a mark recorded on a wobbled groove in a focused-on state from the light reflected back from the wobbled groove. A pull-in signal calculating unit (225) detects a total light volume signal PI of the mark, recorded on the wobbled groove, from the reflected light. A D-flipflop discriminating circuit (244) compares the phase of a binary coded version of a tracking error signal TE detected by the tracking error signal calculating unit to the phase of a binary coded version of the total light volume signal PI as detected by the pull-in signal calculating unit to discriminate the sorts of the optical discs having the same outer shape and the same optical system but differing in the UTOC recording system.

Abstract: A method of selecting laser beam in an optical disk drive is disclosed. A first laser beam (such as CD laser beam) is used to read an optical disk and generate a first testing result. Whether the first testing result is normal is then determined. The first laser beam is used to read data from the optical disk if the first testing result is normal, and a second laser beam (such as DVD laser beam) is, in stead, used to read data from the optical disk if the first testing result is abnormal.

Abstract: A method is provided for discriminating the type of a multi-layer optical disc. This method can accurately discriminate the type of a multi-layer optical disc loaded in an optical disc player such as a DVD player, based on the detection time interval between successive focus OK signals. The multi-layer optical disc may have diverse types such as a DVD-dual layer type and a hybrid super audio CD type. In accordance with this method, it is possible to achieve normal servo and signal processing operations according to the type of the multi-layer optical disc.

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: A DVD recognition method and apparatus is disclosed. First, a disc recognition apparatus uses a laser with a specific wavelength to irradiate an inner area of the DVD, thereby obtaining an inner TE signal. Then, the disc recognition apparatus uses the laser to irradiate an outer area of the DVD, thereby obtaining an outer TE signal. Afterward, the type of the DVD is recognized according to the inner and outer TE signals.

Abstract: A method for correcting disc type determination is disclosed. The method detects a tracking error signal, and verifies accuracy of a disc type determination according thereto.

Abstract: A method of one embodiment of the invention is disclosed that determines optical disc vertical displacement information at a number of positions on an optical disc. The method interpolates optical disc vertical displacement information at a number of other positions on the optical disc from the vertical displacement information determined.