Abstract: A recording/reproducing apparatus includes: a light source; a first correction section to correct a position of an objective lens that collects laser light from the light source on a surface of an optical disc based on a focus bias setting value obtained from a focus bias value; a second correction section to correct an aberration of the laser light based on an aberration correction setting value obtained from an aberration correction value; an evaluation value generation section to generate an evaluation value; a focus bias adjustment section to change plus/minus of the focus bias value and calculate a new focus bias value based on the evaluation value every time a first cycle passes; and an aberration adjustment section to change plus/minus of the aberration correction value and calculate a new aberration correction value every time a second cycle passes, in parallel with an update of the focus bias value.

Abstract: The whole reflection signal and a tracking error signal are detected while an objective lens is being moved in the radial direction of an optical disk, and the temporal difference between a time at which the value of the whole reflection signal becomes a maximum and a time at which the value of the tracking error signal becomes zero is detected in a predetermined time period. In addition, a value which is obtained by dividing the temporal difference by the time period of one cycle of the tracking error signal is acquired as a tilt appearance magnitude. Relational information in which a tilt appearance magnitude and a tilt correction magnitude corresponding to the tilt appearance magnitude are associated is read out, and the relational information read out and the current tilt appearance magnitude detected by a tilt-appearance-magnitude detection circuit are compared, thereby to determine the tilt correction magnitude necessary for a tilt correction.

Abstract: A servo control system and method is provided, comprising: a controller outputting a parameter control signal; a device having a parameter controlled based on the parameter control signal; a sensing circuit sensing the parameter of the device and generating a parameter error signal; a sinusoidal signal generator generating a sinusoidal signal; and a adder combining the parameter error signal and the sinusoidal signal, wherein the controller includes a servo equalizer that equalizes the added parameter error signal and the sinusoidal signal to output an equalized parameter control signal to adjust the parameter.

Abstract: An optical pick-up device in which two object lenses correct comatic aberration with respect to object lenses. First and second optical systems converge either one of light beams having first, second and third wavelengths onto an optical disc. Object lenses are displaced in three axial focusing directions including a direction perpendicular to the recording surface of the optical disc, a tracking direction radial to the optical disc, and either one of a radial tilt direction in a circular arc form on the axis of the radial direction and a tangential tilt direction in a circular arc form on the axis in a tangential direction perpendicular to the radial direction. Comatic aberration of the second optical system is corrected relative to the first optical system in the other direction of the radial tilt direction and the tangential tilt direction, which is not controlled by the object lens drive unit, is corrected.

Abstract: An optical pickup device includes: a light source; an objective lens which condenses a light beam that is emitted from the light source on a recording layer of an optical recording medium; and a photo detector which receives reflected light that is reflected by the optical recording medium. Further on an optical path between the light source and the objective lens, a liquid lens which performs correction of spherical aberration by changing state of convergence or divergence of the input light beam and a liquid crystal element on which a plurality of phase shift regions are formed to adjust phase of the input light beam, and which performs correction of the spherical aberration by phase adjustment of the phase shift regions are arranged.

Abstract: A method of adjusting spherical aberration correction and focus offset of a light beam. A first approximate straight line is detected indicating a first relationship between the spherical aberration correction and the focus offset according to a first evaluation index indicating a quality of cross-track signal. A second approximate straight line is detected indicating a second relationship between the spherical aberration correction and the focus offset according to a second evaluation index indicating a quality of a reproduced signal. A spherical aberration correction value and a focus offset value, to be adjusted, are determined from an intersection of the first approximate straight line and the second approximate straight line.

Abstract: The present invention relates to a method for operating an optical drive system capable of reproducing/recording information from/to an optical carrier (30), wherein a position error and a speed error of a radiation spot (12, 53) on the carrier has been created due to an unreliable error signal which has been generated due to a surface defect (52). The method includes the steps of registering values of e.g. servo signals, determining the occurrence of a defect using a defect detector DEFO (22), generating a first and a second compensation signal and applying these compensation signals to the control system (10) of the optical drive system. The first compensation signal is capable of reducing the speed error and the second compensation signal is capable of reducing the position error. Thus, the application of the compensation signals immediately after the unreliable error signals reduces the position error and the speed error of the focussed radiation spot (12, 53).

Abstract: An optical pick-up actuator includes a lens holder having tracking and focusing coils which substantially extend in two parallel planes at a side of the lens holder. A magnet system cooperates with the tracking and focusing coils and is arranged separately from the lens holder and extends beyond the planes. The coils are arranged for effecting tilt through cooperation with the magnet system and may be provided at each of two opposite sides of the lens holder.

Abstract: A method for tuning a plurality of write strategy parameters of an optical storage device includes detecting a plurality of lengths, each length corresponding to a pit or a land on an optical storage medium accessed by the optical storage device, performing calculations corresponding to a plurality of data set types and generating a plurality of data-to-clock edge deviations respectively corresponding to the data set types, and utilizing the data-to-clock edge deviations for tuning the write strategy parameters corresponding to the data set types respectively.

Abstract: An optical disk drive capable of detecting occurrence of tooth jump in a mechanism for transferring an optical pickup. The optical pickup is transferred in a radial direction of an optical disk by means of a stepping motor. A control section having received a seek operation command from a host machine drives the stepping motor by way of a controller, to thus cause the optical pickup to perform seek up to a target address. The amount of displacement between a current address achieved after seek operation and a target address is computed. When the amount of displacement is equal to or greater than a pitch P of the transfer mechanism; namely, the pitch P of a lead screw, the tooth jump is determined to have arisen. Seek conditions are changed, and seek is reperformed.

Abstract: An optical disk drive includes a pickup apparatus and a servo error correction unit. The pickup apparatus reads data recorded on an optical disk or records encoded data on the optical disk. The pickup apparatus includes a servo control unit. The servo error correction unit generates, based upon data read by the pickup apparatus, a tilt control signal to correct the tilt of the pickup apparatus generated as a result of the eccentricity of the optical disk and the tilt of the optical disk,. The servo control unit of the pickup apparatus controls the tilt of the optical disk and the tilt of the pickup apparatus in response to the tilt control signal.

Abstract: An optical pickup actuator includes a lens holder on which a plurality of object lenses to use in recording/reproducing information onto/from different kinds of optical media are mounted, a tilting unit tilting the lens holder, and a controller controlling the tilting unit to tilt the lens holder about one of the object lenses that is appropriate to use in recording/reproducing information onto/from a kind of optical medium to be used.

Abstract: Fifth order spherical aberration in addition to third order spherical aberration for an optical information recording medium of which thickness of a light transmission layer changes greatly is corrected. An objective lens collects a laser beam emitted from a semiconductor laser on an optical information recording medium. A spherical aberration correcting portion corrects spherical aberration generated according to a thickness of the light transmission layer of the optical information recording medium, in which the spherical aberration correcting portion includes a collimator lens, a lens holder and a stepping motor for correcting the third order spherical aberration and a liquid crystal element and an applied voltage control portion for correcting the fifth order spherical aberration.

Abstract: A method for tuning a plurality of write strategy parameters of an optical storage device includes detecting a plurality of lengths, each length corresponding to a pit or a land on an optical storage medium accessed by the optical storage device, performing calculations corresponding to a plurality of data set types and generating a plurality of data-to-clock edge deviations respectively corresponding to the data set types, and utilizing the data-to-clock edge deviations for tuning the write strategy parameters corresponding to the data set types respectively.

Abstract: An optimum method for adjusting the physical position or angle of an optical pickup (a1) is automatically selected for each optical disc signal processing device so that a control target value after adjusted is included in a previous margin measurement result which is stored in a nonvolatile memory, thereby providing an optical disc signal processing device, an optical disc signal processing method, an optical disc reproduction and recording device, and an optical disc reproduction and recording method, which can reduce the start-up time and the recording start time, and enhance the user's convenience.

Abstract: There is provided an optical disc control device which can perform stable repetitive control without deteriorating the followability of a target value when performing jumping, retry, and long seek.

Abstract: An optical disk device includes an optical pickup, a measurement unit and a control unit. The optical pickup is configured to emit laser light to a disk to record data. The measurement unit is operatively coupled to the optical pickup to measure a peak value of a RF signal outputted from the optical pickup, a fluctuation amplitude of the peak value of the RF signal and an amplitude of the focus drive signal of the optical pickup. The control unit is operatively coupled to the measurement unit to correct the peak value of the RF signal measured during a second recording based on the fluctuation amplitude of the peak value of the RF signal and the amplitude of the focus drive signal measured during a first recording prior to the second recording.

Abstract: A reproducing apparatus includes a head unit operable to direct a laser light beam onto a recording medium, the head unit having a focus servo mechanism and a spherical aberration correction mechanism for laser light; an evaluation signal generating unit operable to generate an evaluation signal serving as an index of quality of a reproduced signal; a focus servo unit operable to perform a focus servo operation by driving the focus servo mechanism in response to a focus error signal; a spherical aberration correction unit operable to perform spherical aberration correction by driving the spherical aberration correction mechanism in response to a spherical aberration correction value; a focus bias unit operable to add a focus bias to a focus loop containing the focus servo unit; and a control unit operable to control adjustment of a spherical aberration correction value and a focus bias value to be set in the spherical aberration correction unit and the focus bias unit, respectively.

Abstract: An optical information recording and reproducing apparatus includes a light source for emitting a light beam, a head unit, including an objective lens and a solid immersion lens, that allows a light beam from the light source to reach an optical recording medium as evanescent light, and a photodetector that detects returning light that returns from a bottom surface of the solid immersion lens for detecting a gap and a tilt between the optical recording medium and the solid immersion lens. The photodetector has a first section and a second section, along a direction in which the returning light is moved in the photodetector, when the solid immersion lens is driven in a tracking direction with respect to the optical recording medium. An area of the returning light in the first section and an area of the returning light in the second section is constant, even when the solid immersion lens is driven in the tracking direction.

Abstract: A kind of an optical disc is discriminated by a disc discriminating section, an order of aberrations to be corrected is set by an order setting section by the kind of the optical disc, drive of a liquid crystal optical element is controlled by a drive control section through a liquid crystal driver, and an aberration of an optical beam is corrected based on the order of the aberration. The level of importance of the aberration correction differs by the kind of the optical disc, and the order of the aberration is set by the level of importance of the aberration correction.

Abstract: A system and methods for evaluating the response of an optical digital disk player to anomalies in optical digital disks are provided. The system includes a simulator configured to provide digital simulated output signals simulating the output of an optical digital disk player during playback of an optical digital disk having an anomaly. The system also includes digital-to-analog converter circuitry to convert the digital simulated output signals to analog simulated output signals and provide the analog simulated output signals to processing circuitry. The processing circuitry generates control signals based on the value of the analog simulated output signals, and provides the control signals as outputs.

Abstract: The light emitted from a semiconductor laser is divided by a diffractive optical element into three light beams which are 0th-order light as the main beam and ±1st-order diffracted lights as the sub-beams, and the track error signals by the main beam and the sub-beams are detected, respectively, by a differential phase detection method. By the effect of the diffractive optical element, the light intensity distributions of the main beam and the sub-beams become different when making incidence on an objective lens. Therefore, when there is radial tilt in a disk, the phases of the track error signals by the main beam and the sub-beams are shifted with each other. Based on the shift in the phases of the track error signals, radial tilt of the disk is detected.

Abstract: A method and apparatus for controlling tilt in an optical disc device are provided. The method includes determining tilt offset values corresponding to different positions of an optical disc for a first tilt control mode, and deciding whether to switch to a static tilt control mode, based on a difference between the detected tilt offset values. If the disc is subject to defect management, a static tilt control mode is selected so that stable focus and tracking servo operations are maintained. If the disc is not subject to defect management, a dynamic tilt control mode is selected so that tilt control optimal for the skew of the optical disc, which gradually increases towards the outer perimeter of the disc, is performed. If the difference between tilt offset values detected respectively for inner and outer peripheral areas of the disc is small when the dynamic tilt control mode is selected, the device determines that the skew is low and changes the tilt control mode to the static tilt control mode.

Abstract: A system that generates vibrations within a computer system. During operation, the system receives a desired vibration profile. Next, the system determines a sequence of disk operations for one or more disk drives within the computer system that generates vibrations which substantially matches the desired vibration profile. The system then performs the sequence of disk operations on the one or more disk drives to generate the vibrations.

Abstract: A servo control of an optical disk apparatus increases a suppression degree of an iterative learning control system, against a frequency disturbance of integer multiple of rotation frequency in a predetermined rotation phase range including a range, in which a servo deviation is detected, of the rotation phase.

Abstract: An optical pickup unit for recording information on and/or reproducing information from a multilayer information recording medium including multiple recording surfaces in each of which a guide groove on which the information is to be recorded is spirally formed is disclosed. The optical pickup unit includes a light source, a diffraction element configured to split the light beam emitted from the light source into a main light beam and first and second sub light beams, an objective lens for focusing the main and sub light beams onto a recording surface of the multilayer information recording medium, and multiple light receiving elements each divided into light receiving parts so as to receive the main and sub light beams reflected from the recording surface. The focused first and second sub light beams are disposed at respective positions at least 3/2 tracks away from the focused main light beam on the recording surface.

Abstract: An optical head comprising a light source, objective lens, light splitting means, light receiving element, tracking error signal detection means, and spherical aberration detection means. Light splitting means has six regions divided by a first splitting line parallel to a longitudinal direction of information tracks, and second and third splitting lines perpendicular to the first line. Spherical aberration detection means compares a first focal point shift amount obtained by detecting a light spot size formed by focusing light fluxes, created by laser light passing through two regions between the second and third splitting lines, onto the light receiving element, and a second focal point shift amount obtained by detecting light spot size formed by focusing light fluxes, created by laser light passing through the four regions, on the outer side of second and third splitting lines, generating a spherical aberration error signal for detecting spherical aberration at the objective lens.

Abstract: A holographic memory system is disclosed. The holographic memory system comprises: a light source configured to generate a light beam; a photosensitive holographic storage medium configured to at least partially reflect the light beam; and an alignment module configured to determine an angular orientation of the storage medium based on the reflected light beam.

Abstract: The present invention relates to a device (1) for scanning an optical recording medium (3), comprising an optical unit (5) for reading data from and/or writing data to said recording medium (3) by scanning said recording medium (3) with a radiation beam (21), said radiation beam (21) being positioned on said recording medium (3) in response to a tracking error signal, a tracking means (7) for generating said tracking error signal and a position control means (11) for controlling a radial scanning position of said radiation beam (21) in respect to a track on said recording medium (3).

Abstract: This optical disk device includes a pickup head, a spindle motor, a signal generation unit, a runout amount calculation unit, and an out of balance disk detection unit. The signal generation unit generates a tracking error signal. The runout amount calculation unit controls the rotational speed of the spindle motor to first and second disk rotational speeds, and obtains, at these rotational speeds, runout amounts TE1 and TE2 of a tracking error signal, and runout amounts FE1 and FE2 of a focus error signal. And an out of balance disk detection unit detects that this optical disk is an out of balance disk, if the absolute value of (TE2×FE2)/(TE1×FE1) is greater than or equal to a threshold value.

Abstract: In a method for compensating recording power, being suitable for an optical disk apparatus, applying the WOPC therein, as a means for compensating recording power during recording operation, and also an optical disk apparatus applying the same therein, wherein the recording operation is interrupted, when a predetermined amount of data is recorded continuously, to determine the recording power for when recoding next, from the recoding condition onto the optical disk just before interruption thereof, and thereby starting the recording, with the recording power determined from that just after said interruption thereof, wherein an adjustment is made on a tilt angle of an optical pickup when the recording power, which is determined when interrupting the recording operation, exceeds a predetermined threshold value, and the recording is started just after said interruption, with the recording power onto the optical disk just before it is interrupted.

Abstract: A beam spot position control device, for controlling multiple beam spot positions irradiated onto an optical recording medium so as to be disposed linearly, includes a light detecting unit for detecting the amount of return light for each of a plurality of beam spots disposed linearly, a tracking control unit for performing tracking control based on tracking error signals of at least one of the beam spots detected with the optical detecting unit, and a rotation control unit for rotating the plurality of beam spots which are disposed linearly, based on the DC offset amount of the tracking error signals of at least two of the beam spots detected with the optical detecting unit.

Abstract: A disclosed optical pickup includes an aberration correction unit with a phase shifter surface. On the phase shifter surface, rectangular or staircase-like steps are formed in a concentric manner around an optical axial center, in certain regions where a light beam passes through. The steps have different heights in the optical axial direction. A light beam having a wavelength of 405 nm is directly transmitted through the steps so that a phase difference is applied for correcting spherical aberration that occurs on a first optical recording medium. A light beam that passes through an annular region without any steps is focused on a second optical recording medium. A light beam that passes through an outside region is focused by an object lens on the second optical recording medium, and is not focused on the first optical recording medium.

Abstract: A method for adjusting a tilt angle of a light beam emitted by an optical pickup unit of an optical disc drive, the method includes steps of adjusting the tilt angle of the light beam according to test parameters preinstalled in the optical disc drive; detecting focusing error signals, the focusing error signals being generated based on the light beam reflected from an optical disc; generating current parameters based on the focusing error signals; storing the current parameters; adjusting the tilt angle of the light beam according to the current parameters.

Abstract: An optical disc drive apparatus may include an optical pickup that moves along a transportation shaft provided along a radial direction of an optical disc and picks up reflected light after emitting an optical beam via an objective lens to the optical disc; a drive section that controls the objective lens to adjust an angle of the optical beam; an angular velocity detection section that detects an angular velocity around the transportation shaft; storage means for storing coefficients from which the skew of the optical disc around a virtual axis perpendicular to the transportation shaft is calculated using the angular velocity; a skew estimation section that calculates a skew estimate value by multiplying the coefficient by the angular velocity; and a drive signal generation section that generates a drive signal based on the skew estimate value to enable the drive section to adjust the angle of the optical beam.

Abstract: An optical disc device recording method, which includes determining whether or not a recording process that records information on a label surface of an optical disc has failed, detecting a recording failure position at which the recording process has failed when the determining step determines the recording process has failed, and resuming the recording process from the detected recording failure position.

Abstract: An optical pickup which includes first to third light sources each emitting a light beam each having a first to third wavelength; an objective lens condensing each of the light beams emitted from the light sources on a signal recording face of an optical disc; a collimator lens provided between the light sources and the objective lens to convert a divergent angle of each of the light beams emitted from the light sources so as to obtain a parallel light beam; and a diffractive optical element provided between the collimator lens and the objective lens. The diffractive optical element includes first and second diffractive parts which respectively diffract the light beam having the second wavelength and the third wavelength. The second diffractive part has a diffraction structure formed by a plurality of concentric ring zones, having first to fourth optical faces, each having a different height in an optical axis direction.

Abstract: An optical information reproducing apparatus and an optical information reproducing method using the same are provided. The optical information reproducing apparatus includes: a light source; a beam splitter which splits a beam emitted from the light source into a reference beam and a temporary beam; a temporary beam splitter which splits the temporary beam into a pair of assistant beams; an incident optical system which inputs the reference beam and the assistant beams to a recording medium in which optical information is recorded; a reproduction beam detector which detects reproduction beams reproduced in response to the reference beam, sets the position of the reproduction beam having the largest light intensity as a reference position, and sets a signal region on the basis of the reference beam; and an assistant beam detector which compares the light intensity of the assistant beams incident on the signal region with each other and sets an incident angle of the reference beam.

Abstract: An optical disk apparatus includes a movable part having an objective lens for focusing a laser beam onto an optical disk. A lens-holding member holds the objective lens. A protecting member prevents contact of the objective lens with the optical disk. The protecting member is spaced apart from the optical disk. An elastic supporting member supports the movable part, and an actuator drives the movable part toward or away from the optical disk. The apparatus is constructed so as to maintain the protecting member spaced apart from the optical disk, even when the elastic supporting member is bent by gravity toward the optical disk.

Abstract: The invention provides an optical disk drive. In one embodiment, the optical disk drive comprises a feeding device, a power driver, and a controller. The feeding device comprises a spherical aberration (SA) lens and a stepping motor, wherein the SA lens corrects spherical aberration of a light beam emitted by a pickup head, and the stepping motor moves the SA lens according to a plurality of control signals. The power driver generates the control signals to drive the stepping motor to move the SA lens. The controller directs the power driver to drive the stepping motor to move the SA lens with only stable steps when the SA lens is required to move, so that the stepping motor is in a stable state without inducing step errors after the stepping motor rotates with the stable steps.

Abstract: An optical pickup and an optical information recording and reproducing device in which spherical aberration correction control after a disc is loaded can be efficiently made in a short time. Before an information recording medium is loaded into a drive, an optical axis direction position of a concave lens is preset to a state so as to optimize a converging spot on a recording surface of a single-layered medium of as a first recording medium or a predetermined layer (first layer having a substrate thickness of 0.1 mm) of a medium having two or more layers to which the recording/reproduction is executed by a laser light source. After the information recording medium is loaded, if it is determined to be a second (third) recording medium to which the recording/reproduction is executed by a laser light source, setting of the optical axis direction position of the concave lens is changed.

Abstract: A disk drive apparatus includes: head means for performing laser irradiation to and detection of reflected light from an optical disk recording medium and having a focus bias mechanism and a spherical aberration correction mechanism; focus bias means for driving the focus bias mechanism to add a focus bias to a focus servo loop; spherical aberration correction means for driving the spherical aberration correction mechanism based on a spherical aberration correction value; evaluation value creating means for creating an evaluation value based on reflected light information obtained by the head means; adjustment means for adjusting the focus bias and the spherical aberration correction value; and control means for determining whether data is written on at least one track of the tracks adjacent to an adjustment use range on the recording medium and controlling an adjustment operation on the focus bias and the spherical aberration correction value by the adjustment means based on the determination result.

Abstract: There is provided an optical disc drive including a light axis deviation detection means (13) which detects a light axis deviation amount of an emission light, a tilt correction control means (15) which determines and outputs a tilt correction amount on the basis of an output of the light axis deviation detection means (13), a microcomputer (10B) which corrects an output of the tilt correction control means (15) and a warpage of a disc, and an addition means (16) which adds an output of the microcomputer (10B) and the output of the tilt correction control means (15), wherein a tilt actuator (2-9) is driven by an output of the addition means (16) through a tilt drive means (11) to control a tilt of an objective lens which focuses a light beam on the disc.

Abstract: An optical pickup module with enhanced aberration correctability is disclosed. This pickup includes more than two different types of laser light sources, an objective lens for collecting and focusing any one of the laser beams leaving the light sources onto an optical disc, and an aberration correction device of the liquid crystal (LC) type, which is disposed between the light sources and the objective lens. The aberration corrector has a surface on which multiple spaced-apart electrodes are patterned for enabling aberration correction relative to incident beams. The corrector controls the potential of a voltage being applied to each electrode in deference to incident beam properties and variations occurrable thereto, e.g., wavelength, effective beam diameter and relative incidence position offsets, thereby to optimally correct beam aberrations, such as coma aberration or wavefront aberration. An optical information reproduction apparatus using the pickup is also disclosed.

Abstract: An optical pickup (20) projects a read beam onto an optical disc (40) as an optical storage medium which is driven to rotate by a spindle motor (30) and receives its reflection. A laser beam from a laser producing element (21) passes through a liquid crystal panel (25) and guided to an objective lens (26). The panel (25) is provided to correct spherical aberration caused by an irregular thickness of a transparent substrate of the optical disc (40). A control circuit (50) changes a spherical aberration correction signal SA to carry out sampling more than once, covering a range of the output of an optical sensor (31) where the output shows large changes. The circuit (50) determines the position of a peak of an approximation curve through calculation and designates that position as the magnitude of correction. Thus, the optical pickup (20) can quickly and accurately detect the magnitude of the correction of the spherical aberration caused by an irregular thickness of the optical disc (40).

Abstract: An object of the present invention is to provide a focus out detecting apparatus which detects focus out with accuracy during reproducing or recording of data from/on an optical disc having a plurality of recording layers. Further, another object of the present invention is to provide an optical disc apparatus in which a recording or reproducing performance of data is improved by use of the focus out detecting apparatus. A focus out detection signal is output when a level of a focus error signal exceeds a first predetermined level, then reflected light quantity from the optical disc becomes lower than a third predetermined level in a predetermined period, and then the level of the focus error signal exceeds a second predetermined level of an opposite polarity to the first predetermined level.

Abstract: An optical disc apparatus reliably executes a seek operation even if an optical disc is warped. Tilt adjustment values spanning from the inner circumference to the outer circumference of an optical disc are stored. When seeking from a start address to a destination address, a tilt adjustment value A at the start address and a tilt adjustment address C at the destination address are not directly used. A tilt adjustment value k·C (k<1) is used during a coarse seek operation until the neighborhood of the destination address and a tilt adjustment value C is used during a fine seek operation from the neighborhood of the destination address to the destination address.

Abstract: An optical pickup apparatus includes an objective lens that focuses light on an optical recording medium; an actuator that drives the objective lens in a direction of an optical axis of the objective lens toward or away from an optical recording medium in response to an input voltage applied to the actuator; an actuator driven distance sensor that senses a distance the actuator moves according to time or the input voltage applied to the actuator; an input voltage calculator that calculates an input voltage to be applied to the actuator that compensates for a hysteresis phenomenon that occurs during movement of the actuator based on the distance sensed by the actuator driven distance sensor; and a controller that controls operation of the actuator according to the input voltage calculated by the input voltage calculator.

Abstract: An optical pickup device for recording and reproducing information by tilting and horizontally driving a lens holder, holding an objective lens, to irradiate an optical disk with a recording/reproducing laser light from a light source. The optical pickup device has a reflector for reflecting a portion of the recording/reproducing laser light led to the lens holder from the light source; a detector fixedly placed at a position at which the amount of received light for detection, which is the recording/reproducing laser light reflected by the reflector, varies according to the tilt angle of the lens holder; and tilt angle acquisition means for acquiring the tilt angle of the objective lens from the light receiving amount detected by the detector.

Abstract: A system controller of an optical disk recording and reproducing device writes test data in a test writable area of a loaded optical disk if it is an unused disk and calculates a maximum amplitude value of an RF signal at an inner radius. Then, it calculates the maximum amplitude value of a tracking error signal at the inner radius and further calculates the maximum amplitude value of the tracking error signal at the outer radius. After that, it calculates a primary approximate expression about a tilt from the maximum amplitude value of the tracking error signal at the inner radius and the maximum amplitude value of the tracking error signal at the outer radius. It further offsets the primary approximate expression by a difference between the tilt values that is obtained by subtracting the maximum amplitude value of the tracking error signal at the inner radius from the maximum amplitude value of the RF signal at the inner radius.