Abstract: An optical pickup actuator and an optical pickup using the same, wherein the optical pickup actuator has: a lens holder, on which an objective lens is mounted; and a tilt photodetector, which is installed in the lens holder and receives a portion of light used to record and/or to reproduce information on and/or from a recording medium according to a relative tilt between the objective lens and the recording medium. The optical pickup actuator moves the objective lens in a tracking direction, a focusing direction, and a tilting direction. The optical pickup actuator can detect both tilt of the recording medium and tilt of the objective lens using the tilt photodetector, so the optical pickup can be applied to an optical recording and/or reproducing apparatus of high-density and/or high-speed.

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: The object of the present invention is to propose an optical disk driving apparatus, an optical disk driving method and an optical disk apparatus capable of reducing the occurrence of disturbance to focus servo control and tracking servo control. In the optical disk driving apparatus, a tilt driving section (27) is provided with waveform shaping unit for shaping a driving current waveform driving a tilt motor (28) for changing the angle of an optical pickup (3) with respect to the rotating surface of an optical disk. Thus, it is possible to prevent the vibration of the optical pickup (3), to reduce disturbance derived from the vibration of an objective lens (8) to focus control and tracking control and to suppress mechanical noise while tilt driving is being performed. Besides, since there is no need to provide a tilt sensor, the optical pickup (3) can be made small in size and therefore, the smaller-sized optical disk driving apparatus can be provided.

Abstract: An offset adjustment signal is recorded in a test recording area provided on the inner side of a disc while modifying the level of a driving signal for offset detection that is supplied to a tilt adjustment coil. Thereafter, an operation to play back the offset adjustment signal is performed, and the peak level of an RF signal that is played back is detected. When a signal is recorded for which the detected peak level reaches a maximum, the level of the driving signal supplied to the tilt adjustment coil is set as an offset value. Tilt control is then performed by adding the offset value to a tilt signal for performing tilt control.

Abstract: An aberration correcting device is placed in an optical path extending from a light source of an optical pickup apparatus for irradiating a light beam onto an optical disk to the optical disk. The device includes a pair of light-transmission substrates at least one of which is held freely movable in a way that a major surface thereof moves in a direction vertical to the optical path, and which have complementary curved surfaces facing, and apart from, each other. The curved surfaces are formed in such a manner as to cause the optical path length of a light beam transmitting the pair of light-transmission substrates to be changed by movement of the light-transmission substrates, thus imparting a phase difference to a transmitting light beam, while allowing the phase difference to keep an advancing direction of the light beam thereby to minimize a comatic aberration caused by the optical disk.

Abstract: A system and method for adjusting optical drives. Rotating disc datum, and leader pin datum, must be adjusted to a specific position during a packaging process. An autocollimator according to the present invention senses tilt and sway of the rotating disc, outputting a first bright spot through a switch box to a monitor. In addition, an optimum tilt angle of the optical pickup head is obtained by a reader through calculation by a host, outputting a second bright spot through the switch box to the monitor. Therefore, the first bright is coincided with the second bright spot by a adjustment mechanism and according to picture switch by the switch box, reading optimum tilt angle adjustment. Furthermore, individual tilt angle of each optical pickup head is calculated by a host for satisfying adjustment of different tilt angles with different optical paths in reading CD and DVD discs.

Abstract: A data recording method according to one aspect of this invention comprises specifying a plurality of regions with different radial positions on a disk, and detecting the tilt amounts of the respective regions with respect to the optical axis of a light beam on the basis of a focus control signal used to just-focus the light beam on a recording surface of the disk, calculating tilt correction amounts for the respective regions in accordance with the tilt amounts of the respective regions, correcting a tilt of the optical axis with respect to a predetermined region on the basis of the tilt correction amount corresponding to the predetermined region, and recording data on the predetermined region while the tilt of the optical axis with respect to the predetermined region is corrected.

Abstract: A pickup moving mechanism for making it difficult to generate a deviation between an optical axis of an optical pickup and a target position on a disk. This mechanism is constituted to comprise: an elevation member tilting a guide member based on an angle deviation of the optical axis of the optical pickup in a disk diameter direction, and inclining the optical pickup supported by the guide member in a direction in which the angle deviation of the optical axis decreases; a cam follower; a tilt motor; an eccentric cam; an urging means; and a controller for controlling a pickup motor operating a screw member and an engagement member so as to move the optical pickup in a direction in which the deviation of the optical axis in the disk diameter direction generated by inclination of the optical pickup decreases.

Abstract: An optical information recording and reproducing apparatus capable of recording and reproducing information data accurately with respect to an optical recording medium. The optical information recording and reproducing apparatus includes an aberration correction part which corrects aberration of the optical system. The apparatus determines whether or not an aberration correction by the aberration correction part is completed based on the signal level read from the optical recording medium, while changing a spherical aberration correction amount of the aberration correction part. The apparatus commences a recording operation or a reproducing operation of the optical information recording and reproducing apparatus if it is determined that the aberration correction was completed.

Abstract: An optical disk having a data recording surface, which is prepared by the process, in which two metal molds having curvature surfaces on their cavity sides are used for making substrates having predetermined curvatures, for the optical disk by injection molding, and the substrates are adhered together such that convex surfaces of the substrates are adhered surfaces.

Abstract: An optical-pickup device includes a plurality of light sources, an objective lens for converging light from the plurality of light sources on an optical disc, and at least one light-receiving element for receiving light reflected by the optical disc. A light source of the plurality of light sources, which light source is not used for recording/reproducing, is used for detecting relative tilt between the optical disc and the objective lens.

Abstract: Prior to recording/reproducing information to/from an optical disk rotationally driven by a spindle motor, an optical pickup is moved to a plurality of measuring positions set beforehand in a radial direction of the optical disk. A relative tilt between the optical disk and the optical pickup is detected with the spindle motor being rotated so that a linear velocity at each of the measuring positions equals a linear velocity upon actually recording or reproducing the information thereat. The tilt detected at each of the measuring positions is stored as tilt detection data corresponding to each of the measuring positions.

Abstract: A focus offset setting portion gives a predetermined quantity of offset to a focus control quantity used to reduce a focus error signal to zero based on the focus error signal generated by a focus error generation portion, and outputs a result. An adaptive equalizer including an adaptive control portion and an FIR filter subjects a reproduction signal RF provided from an optical pickup to waveform equalization based on a signal decoded by a Viterbi decoder. A controller obtains an optimum point of a focus offset by using a tap coefficient of the adaptive equalizer, and changes a set value of a focus offset setting portion.

Abstract: An objective lens drive having an optical axis adjustment function. An objective lens is supported by a lens holder, and the lens holder is supported on a suspension holder by way of a suspension. The suspension holder is supported so as to be rotatable about an axis extending in a direction in which the suspension extends, whereby the suspension holder is supported laterally by means of multilayer piezoelectric elements. When a drive voltage is applied to the multilayer piezoelectric elements, the piezoelectric elements are displaced vertically, whereupon the suspension holder is rotated about the axis, to thus adjust the optical axis of the objective lens.

Abstract: An optical disk device has a recording information management portion which detects a distribution of a recorded region R and an unrecorded region M based on reflection light received by an optical head and an access target setting circuit which determines an access target of an optical head so as to make access to a target position of a recording layer of an optical disk while avoiding the unrecorded region M based on the detected distribution of the regions. Since an access is made while passing through only the recorded region R, a servo operation can be stabilized.

Abstract: In an optical disk apparatus in accordance with the present invention, a tilt chassis (3, 201) to which a main shaft (6) and a sub shaft (7), being parallel with each other and serving to guide the movement direction of an optical pickup (50), are secured is disposed rotatably with respect to a traverse chassis (4) to which a spindle motor (2) is secured, and the tilt chassis (3, 201) is configured so as to be tilt-adjustable with respect to the traverse chassis (4) by tilt adjustment means having two tilt adjustment portions (30, 31), whereby tilt adjustment work for adjusting the movement face of the optical pickup so as to be parallel with the recording face of an optical disk is made easy.

Abstract: When an optical disk is tilted in its radial direction, coma aberration may occur to cause a phase shift in a tracking signal, thereby making tracking control less accurate. There are provided an optical head that records information on an optical disk and/or reproduces information written in the optical disk, the optical head comprising an objective lens 4 that condenses light on the optical disk, light receiving means 8 of receiving a reflected beam from the optical disk to obtain a received light signal, tracking error signal detecting means 9 of detecting a tracking error signal in the received light signal, and optical means 6 of attenuating the quantity of light in a central area of a tracking error signal detecting beam of the reflected beam incident on the light receiving means 8, the tracking error signal detecting beam being used to detect the tracking error signal.

Abstract: A wire-suspended objective lens actuator structure and a method of assigning current pathways. The lens holder on the actuator structure has a group of focusing coils, a group of tracking coils and a group of slant adjustment coils. The coils are connected to four conductive wires. A first conductive wire controls the focusing coil and a second conductive wire controls the tracking coil. Similarly, a third conductive wire controls the slant adjustment coil. The ground terminals of all three groups of coils are connected in parallel to a fourth conductive wire. The fourth conductive wire serves as a common ground terminal. The control terminal of each group of coils is connected to a differential voltage-output current amplifier circuit or a differential voltage-output voltage amplifier circuit. Hence, the focusing, the tracking and the slant adjustment coils can be driven by differential voltages.

Abstract: A method for calibrating a tilt in a disc player includes a disc insertion judgment step, a focus error output time judgment step, a subtraction step, a disc recording surface judgment step, and a tilt calibration step. In the focus error output time judgment step, an optical pickup unit is made to ascend and then descend for a predetermined time, to then judge a first focus error output time at which a focus error is output during ascending and a second focus error output time at which a focus error is output during descending. A focus error output difference time is obtained by subtracting the FET1 from the FET2. In the tilt calibration step, if the FET is not same as a reference focus error output difference time (FETrf), the turntable is made to rotate, to calibrate a tilt between the optical pickup unit and the disc.

Abstract: A method of, and an apparatus for detecting a radial tilt of a disc. Phases of summed signals obtained from signals that external light-receiving units of an octant photo diode receive are compared to generate an external phase comparison signal Do. Phases of other summed signals obtained from other signals, that internal light-receiving units of the octant photo diode receive, are compared to generate the internal phase comparison signal Di. The radial tilt is detected based on the internal and external phase comparison signals Di and Do obtained when a laser beam crosses a track formed the disc. Thus, the radial tilt can be more precisely detected.

Abstract: In a state in which an optical disk having a warping amount equal to or smaller than a predetermined amount is attached to a spindle motor, an output of tilt detection result is stored as a reference tilt value in a memory. At this time, a control signal corresponding to a driving inclining amount in which inclining the objective lens by the driving inclining amount minimizes the inclination of the objective lens from the attached optical disk is stored as a reference control value in the memory. An CPU a multiplies difference between a detection result of the tilt detection and the reference tilt value by a control constant, and adds the reference control value to the multiplied difference, and provides the thus-obtained control signal to a tilt driving circuit.

Abstract: A method for adjusting an optical axis of an optical disc drive. The method includes the following steps. A first reflecting member is disposed on a turntable of the optical disc drive, and is rotated along with the turntable. A laser light is emitted on the first reflecting member by a laser collimator, and a normal vector of the turntable is measured based on a light point reflected to the laser collimator from the first reflecting member. A second reflecting member and a third reflecting member are disposed on a guide bar of the optical disc drive. A first initial vector and a second initial vector are measured based on a light point reflected to the laser collimator from the second reflecting member and the third reflecting member.

Abstract: Disclosed is an optical pick-up actuator including a tilt-compensating magnetic circuit adapted to conduct a tilt compensation depending on current flowing a focusing coil attached to a lens holder maintained in a suspended state. The tilt-compensating magnetic circuit includes magnets or electromagnets for generating a tilt-compensating magnetic field. Alternatively, the tilt-compensating magnetic circuit is configured to allow focusing and tracking magnets and a tracking coil to be movable toward the outer periphery of a disk, to which the optical pick-up actuator is applied. In either configuration, the tilt-compensating magnetic circuit generates a tilt-compensating magnetic field depending on the current flowing through the focusing coil. In accordance with the optical pick-up actuator of the present invention can conduct a tilt compensation depending on a control current flowing the focusing coil at the point of time when a focusing control is required.

Abstract: An object of the present invention is to provide an optical head apparatus which are capable of detecting correctly a radial tilt of an optical recording medium, without allowing offsets in radial tilt signals, even when an objective lens is shifted in a radial direction. A beam emitted from a semiconductor laser is divided into 0th order main beam and ±1st order sub beams. The three beams are shifted in the radial direction of the disc. The three beams reflected from the disc are diffracted by a holographic element, and are received by a photo detector. With respect to the main beam and the sub beams, a radial tilt of the disc is detected on the basis of a difference between intensities of the main and sub beams diffracted from a plurality of regions of the holographic element.

Abstract: An apparatus and method determining an optimum recording power suitable for a disc loaded in a disc drive. The apparatus includes a pickup unit and a control unit. The pickup unit records data in a predetermined area on the disc and reproduces the recorded data from the disc. The control unit controls the disc drive to record data in the predetermined area of the disc using a preset reference recording power. The control unit detects a plurality of recording powers using reproduction signals of the predetermined area reproduced from the pickup unit and one or more reference values, and decides an optimum recording power for the disc based on the detected plurality of recording powers. Thus, the recording power used by an active layer of the disc can be prevented from varying due to hardware error in the disc drive with respect to various kinds of discs.

Abstract: This optical disk device includes an objective lens (7) for condensing radiated light from a light source on an optical disk (8), an optical detecting unit for detecting reflected light from the optical disk (8), and a control unit for performing the tracking control and/or the tilt control of the objective lens (7) by utilizing the output from the optical detecting unit, in which the control unit uses the off-track quantity and/or the tilt quantity of the objective lens (7) when performing the above described control.

Abstract: A tilt of a light beam to be radiated onto an information recording disk is corrected without using a dedicated tilt sensor. The correction is performed based on the characteristic that an offset amount between a tilt amount maximizing an RF signal amplitude and a further tilt amount maximizing an LPP signal amplitude is constant and independent of positions on the same disk. A pre-pit signal indicative of an existence/nonexistence of a pre-pit formed on the disk is produced from returned light of the light beam, while an RF signal is produced from bits of information recorded on the disk on the basis of the returned light. An optimum tilt-correcting amount is decided by making use of a relationship between the pre-pit signal and the RF signal at a particular tilt amount. The tilt amount is corrected using the optimum tilt-correcting amount.

Abstract: A DC voltage value is obtained at least at an inside position, an intermediate position, and an outside position on a disc (1) from a drive signal that is supplied to a focusing coil (4) built into an optical pickup (2). From the DC voltage values is obtained a relationship of a position between the respective positions and the DC voltage value, and this relationship is stored into a memory circuit (12). Then, during recording or playback, the DC voltage value that is calculated on the basis of the recording or playback position of the signal at that time and the AC signal included in the drive signal that is supplied to the focusing coil (4) are added to create a signal to be supplied to a tilt adjustment coil (6).

Abstract: A data recording/reproduction apparatus is provided, which apparatus includes a spindle motor which is held by a base body and rotates an optical disk, an optical pickup which projects a laser beam into a spot on the optical disk for data recording/reproduction, first and second support mechanisms provided on the base body, and a seek mechanism which is held by the first and second support mechanisms so as to be freely tilted with respect to the base body and actuates the optical pickup in radial directions of the optical disk. The first support mechanism is vertically movable in directions of a thickness of the optical disk so that a tilt of the optical pickup with respect to the optical disk is adjusted.

Abstract: An apparatus for driving a record carrier according to the invention comprises a transducer for generating a read signal in response to patterns recorded at the record carrier and displacement means for displacing the transducer and the record carrier with respect to each other. Out of the read signal an auxiliary signal having a relatively low frequency content is generated. The apparatus comprises binary signal generating means for generating a binary signal out of the auxiliary signal including first hold means for generating a first hold signal, second hold means for generating a second hold signal, signal combination means for generating a slicing signal out of the first hold signal and the second hold signal, and comparing means for comparing the auxiliary signal with the slicing signal and outputting a binary output signal. The first hold means are adapted for temporarily maintaining the first hold signal at a value substantially corresponding to a top value of the auxiliary signal.

Abstract: To record information, a recording/reproducing optical system in an optical head irradiates a recording medium with information light and reference light for recording so that two-dimensional image information is recorded on the recording medium by means of interference between the information light and the reference light for recording. To reproduce information, the recording/reproducing optical system irradiates the recording medium with reference light for reproduction, and collects and detects reproduction light occurring from the recording medium. An optical information recording/reproducing apparatus comprises a tilt detector and an image deviation correction circuit. The tilt detector detects a tilt of the recording medium with respect to a predetermined reference position.

Abstract: A tilt detecting device detects and corrects a disc tilt without a dedicated tilt sensor. There is a correlation between an amplitude level of a prepit detection signal and a disc tilt quantity on a disc on which prepits are formed in advance. Namely, the amplitude level of the prepit signal becomes maximum when the disc tilt quantity is zero. Therefore, by controlling a tilt correction quantity such that the amplitude level of the prepit detection signal becomes maximum, the tilt correction can be executed without utilizing a dedicated tilt sensor and the like.

Abstract: The optical pickup moving mechanism includes: a feed screw and a guide shaft, which are arranged in parallel with each other, for movably supporting an optical pickup; and a drive motor for giving a drive force to the feed screw so that the optical pickup can be moved along a recording medium. The skew adjusting mechanism of the optical pickup for adjusting a skew of the optical pickup adjusts a skew of the optical pickup when the feed screw and the guide shaft are respectively moved and adjusted.

Abstract: A tilt servo apparatus which can correct a tilt error at a high speed and with high precision irrespective of a magnitude of the tilt error even if a response speed of a liquid crystal device decreases is provided. An amount of change and an increase/decrease of a signal intensity are detected by changing a correction value of a tilt error correcting arrangement by a first correction width, and a correction width of the correction value and a correcting direction are determined on the basis of the detection result. When the amount of change of the signal intensity is smaller than a predetermined amount of change, the correction width is changed to a second correction width which is smaller than a first correction width. When it is larger than the predetermined amount of change, the correction width is changed to a third correction width larger than the first correction width. The correction width is also determined in accordance with a change in environmental temperature.

Abstract: A tilt adjusting method and apparatus use jitter feedback. The tilt adjusting apparatus includes a jitter detection unit, which detects the jitter quantity of a reproduction signal picked up by a pickup unit, a jitter data preprocessing unit, which filters the jitter quantity in a predetermined window interval unit and obtains a value of an objective function from the filtered jitter data in each predetermined time unit, and a tilt control unit, which obtains a tilt adjusting value by performing tilt control using the value of the objective function and feeds the obtained tilt adjusting value back to a tilt driving unit. According to the tilt-adjusting method and apparatus, when data on an optical disc with a tilt defect is reproduced, quantified jitter values being fed back are adjusted.

Abstract: A tilt servo apparatus of an optical disc recording/reproducing apparatus, which includes sampling portion for sampling an RF envelope signal at every predetermined rotational angle on the basis of a rotation signal being synchronous with a rotation of the optical recording medium, calculating portion for calculating an average value of the sampled envelope intensities, and control portion for controlling a tilt error correction. The control portion determines the amount of the tilt error correction on the basis of the average value.

Abstract: This invention relates to an optical disk apparatus for optically reproducing information recorded on an information carrier by an optical beam emitted by a light source, the optical disk apparatus comprising: a converging section for directing the optical beam to the information carrier in a converged state; a light detection section for generating a reproduction signal corresponding to the optical beam reflected by or transmitted through the information carrier; a waveform equalization section for varying a frequency characteristic of the reproduction signal generated by the light detection section; a jitter measuring section for measuring a jitter of a signal output from the waveform equalization section; and a minimum jitter value searching section for determining a minimum value of the jitter in an initial area of an X-Y plane defined by a variable x and a variable y which can vary the jitter measured by the jitter measuring section. A PLL circuit is disclosed.

Abstract: The present invention relates to an apparatus for reading from and/or writing to optical recording media with optical scanner, light source, focusing means, tilting-detection device and tilting-compensation device. The object of the invention is to propose an apparatus and a method, which enables optimum compensation of tilting using as few apparatus functions as possible. This is achieved according to the invention by using a tilting-detection device comprising an optical grating, a detector element, a control device for controlling light source and the focusing means and a control device controlling for the tilting-compensation device.

Abstract: An apparatus for manufacturing a disc drive comprises an adjusting element, put in contact with a disc table engaged with a rotational shaft of a drive motor via an engaging portion, for varying an inclination of the disc table which is swingable with a point of support at the engaging portion, a non-contact displacement measuring unit for detecting, the inclination of the disc table varied by the adjusting element, control unit for receiving a detection signal from the non-contact displacement measuring unit and stopping rotation of the drive motor when the inclination of the disc table has decreased to a predetermined value or less, and an adhesive supply unit for fixing the disc table to the rotational shaft of the drive motor which has been stopped by the control unit.

Abstract: A recording apparatus capable of recording an optical disk obtained by adhering two substrates having predetermined curvatures with the convex surfaces of the substrates being adhered, wherein a light source irradiates light through an optical set to the optical disk via a converging lens. Plural light detectors are provided for photoelectrically converting reflection light from the data recording surface of the optical disk and returning through the optical set to output respective signals corresponding to a difference in distance between the lens and the data recording surface, a difference between the center of a light beam spot formed at a focal point position of the lens in a center of either one of a track and a pit line on the data recording surface, and a degree of tilt of the data recording surface. Lens movement mechanisms are provided to move the lens perpendicular and parallel to the data recording surface and to cancel the tilt.

Abstract: A method for optical axis adjustment of an optical driver is provided for decreasing interference, providing a reliable sensitive determination with respect to the variation of incident angle for facilitating inspection, and precisely adjusting the incident angle to an optimum. An apparatus for optical axis adjustment of an optical driver including a spindle module for rotating disc, a plurality of adjustment devices for adjusting the oblique angle of spindle module, a read/write device for emitting an incident light signal to disc, receiving a reflected light signal from disc, and outputting a reflected voltage signal, a control circuit device for outputting a rotation control signal to the spindle module for rotating the spindle module, outputting a read/write control signal to the read/write device for emitting/receiving incident light signal, and receiving and outputting the reflected voltage signal, and a feedback device for rotating the adjustment devices in response to reflected voltage signal.

Abstract: A light-emitting element emits a light toward an optical disk. A plurality of light-receiving elements receives the light reflected from the optical disk. A light-shielding member is provided between the optical disk and at least one of the light-emitting element and the light-receiving elements so as to shield parts of the light at both sides in a radial direction of the optical disk. A tilt of the optical disk is detected according to an intensity distribution of the light on the light-receiving elements.

Abstract: A tilt compensating device and method of performing normal tilt compensation in the event of a servo emergency which may occur during reproduction of data from an optical recording medium are provided. The tilt compensating device includes: an optical pickup; a tilt adjusting unit that adjusts a tilt angle of the optical pickup; a jitter detecting unit that detects an amount of jitter in a reproduction signal output from the optical pickup; and a controlling unit that monitors speed at which the optical recording medium operates using a phase-locked loop (PLL) signal generated from the reproduction signal and the degree of focus of the optical pickup, performs an operation to return to a normal state if any abnormality occurs, and controls operation of the tilt adjusting unit by comparing an amount of jitter detected at regular intervals against a reference.

Abstract: Tilt which is inclination of a normal of optical disk relative to optical axis of optical head is corrected with a liquid crystal element. In a driver for the liquid crystal element, a periodic waveform generator generates periodic waveform and an inverting element inverts the periodic waveform. The periodic waveform and the inverted waveform are connected to two ends of a potential divider which provides partial voltages. The periodic waveform is connected to a common electrode of the liquid crystal element, and the partial voltages of the potential divider are connected to electrodes opposing the common electrode. A structure of a driver circuit for each direction is simple. Tilt in a plurality of directions can be performed independently of each other. Spherical aberration is also corrected. When the liquid crystal element is mounted to a fixed component, deterioration due to jitters is reduced.

Abstract: Tilt of an optical storage medium is stably detected even when then the guide groove pitch is reduced and recording capacity is increased. On a disk with continuous grooves of a pitch Gp, part of tracks Gn−1 and Gn+1 adjacent to opposite sides of an n-th track Gn is eliminated, forming an area where the groove pitch is equivalent to 2·Gp. A push-pull signal from the area of groove pitch Gp and a push-pull signal from the area of groove pitch 2·Gp are differentiated to obtain a tilt error signal. Tilt can therefore be detected even when groove pitch Gp is reduced and storage capacity is increased, and a highly reliable data recording and reproducing apparatus can be provided at low cost.

Abstract: A method for compensating for tilt in reproducing an optical reproducing medium is performed by determining an initial tilt driving direction so as to not interrupt a reproducer when tilt compensation is performed on the optical recording medium. The tilt compensation method involves comparing the amount of jitter detected over a certain period of time when the optical recording medium is reproduced with a reference value; determining the direction of tilt compensation in the direction of reproducing a track of the optical recording medium, before performing tilt compensation, when the amount of jitter detected, according to a comparison result of the comparator, exceeds a reference value; and resuming reproduction of the optical recording medium after performing tilt compensation so that the jitter decreases in the direction of the determined tilt compensation.

Abstract: An optical disk apparatus includes a tilt detection unit detecting the tilt value of an optical disk medium with respect to an optical system. A tilt compensation unit compensates for the tilt of the optical disk medium by adjusting a relative angle between the optical system and the optical disk medium according to the tilt value detected by the tilt detection unit. A tilt detection error estimation unit estimates tilt detection error of the tilt detection unit with respect to a radial position of the optical disk medium at which information is recorded/reproduced by the optical systems by referring to tilt values that are previously detected at a plurality of radial positions of the optical disk medium by the tilt detection unit. The tilt compensation unit has a correction unit that corrects the tilt value according to the tilt detection error estimated by the tilt detection error estimation unit.

Abstract: An objective lens (1) for focusing light on an optical recording medium (not shown) and irradiating the same with the focused light is held on a lens holder (2). A support member (10) is provided on a base member (9) as a foundation of a device for driving optical system. The lens holder (2) is supported on the support member (10). Six linear elastic bodies (7a through 7f) of the same length are cylindrically shaped. The lens holder (2) is supported on the support member (10) by the linear elastic bodies (7a through 7f). A center of a circle formed by the ends of the linear elastic bodies (7a through 7f) is an axis of point symmetry thereof. Distances between adjacent ones of the ends of the linear elastic bodies (7a through 7f) are all the same.

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: An automatic tilt compensator senses and automatically compensates for a disc deformation while an optical recording and/or reproducing apparatus operates. The automatic tilt compensator of an optical recording/reproducing apparatus has a disc deformation detecting section for sensing a deformation direction and a deformation degree of a disc seated and rotated on a disc rotation unit of a deck base and for outputting a predetermined signal, and a level adjustment section for elevating and lowering a pair of guide shafts movably supporting a pickup unit on the deck base while being operated by the signal from the disc deformation detecting section, to thereby adjust the level of the pickup unit corresponding to the deformation degree of the disc. According to this, the level of the pickup unit according to the deformation direction or the deformation degree of the disc can be automatically adjusted while the optical recording/reproducing device is operated.