Abstract: The present invention provides an optical pick-up device capable of suppressing the inclination of a lens actuator in the jitter direction caused by the variation of the ambient temperature thereof to stably record or reproduce information to or from an optical disk. In the optical pick-up device, a supporting member 106 for fixing one end of each of suspension members 105 is arranged on a rear side of a suspension holder 2 fixed to a yoke base 103, and an object lens 102 is displaced by servo-controlling a lens holder 101 for holding the other ends of the suspension members in an electromagnetic driving manner to adjust the irradiation position of a beam spot on an optical disk. The suspension holder 2 is formed of a plurality of members having different coefficients of linear expansion, and the members having a higher coefficient of linear expansion are arranged on the rear side of the suspension holder 2.

Abstract: A disturbance compensation determination apparatus, a related method, a computer readable medium storing a computer program related to the method, and a disk drive comprising the apparatus are provided. The disturbance compensation determination apparatus includes a disturbance observer (DOB) receiving a control input signal and a servo output signal of a plant, wherein the DOB calculates and outputs a current estimated disturbance value. The apparatus also includes a disturbance evaluation unit selectively changing a current disturbance compensation (DC) mode, wherein selectively changing the current DC mode comprises evaluating an accumulated estimated disturbance value in accordance with a condition corresponding to the current DC mode. In addition, the apparatus includes a switching unit selectively providing the current estimated disturbance value to a control loop of the plant in accordance with the current DC mode as selectively changed by the disturbance evaluation unit.

Abstract: The present invention provides a disk playback device comprising a control circuit 7 for determining an optimum value of offset for a focus error signal based on amplitude values of a tracking error signal or an RF signal fed from an optical head 5, and making an offset adjustment with reference to the optimum value. The control circuit 7, in signal reproduction, approximates the relationship between offset values and the amplitude values to a quadratic curve with reference to three different offset values and three amplitudes at the respective offset values, repeats a calculation of an optimum offset value corresponding to the peak of the quadratic curve, and sets the three different first to third offset values respectively at an optimum value obtained in a previous optimum offset value calculation processing, and second and third offset values set in the previous optimum offset value calculation processing.

Abstract: Before each content file is recorded first to a recording medium, a flag indicating a recording state of a content file is generated corresponding to a physical area where an index file can be continuously recorded. An index file is generated which associates attribute information with the generated flag added thereto with real data of each content file, and the generated index file is recorded to the recording medium. Since fragmentation of the physical area where the index file is recorded is restrained to a minimum level, a high-speed reading operation is realized.

Abstract: The invention relates to an actuator position control method for use in a recorded information reproducing apparatus. Front, main and rear beams are directed onto a recorded track formed on a rotating optical recording medium and respective first, second and third signals are produced in response to light reflected by said recorded track when scanned by the front, main and rear beams. The control method comprises the steps of producing from a source of light said beams; scanning with said main beam the recorded track; controlling the position of said main beam with respect to the recorded track in response to position control signals generated from said first and third signals, and reading the recorded information by means of a processing operation of said second signal.

Abstract: An optical disk unit of this invention includes a defocus detecting system for detecting a defocus of an objective lens, a thickness unevenness detecting system for detecting a thickness unevenness of a transparent resin layer provided nearest the objective lens of a recording medium, and a thickness unevenness correcting mechanism for changing the focusing characteristic of light impinging upon the objective lens based on a change in the thickness of the transparent resin layer detected by the thickness detecting system.

Abstract: An auto-adjusting system for an optical incident angle comprises a memory, a linear tilt calculation unit, a non-linear tilt calculation unit, a controller, and a tilt actuator. The memory is used for storing a linear tilt compensation table and a non-linear tilt compensation table. The linear tilt calculation unit is used for calculating the corresponding linear tilt dac value by consulting the linear tilt compensation table according to a first radius and a focus output voltage. According to a predetermined comparison procedure, the non-linear tilt calculation unit is used for generating a second radius wherein the compact disc begins to generate non-linear deformation and then obtaining the corresponding non-linear tilt compensation parameter by consulting the non-linear tilt compensation table according to the first radius and the second radius. The controller is used for controlling the pickup head, the memory, the linear tilt calculation unit, and the non-linear tilt calculation unit.

Abstract: An optical disk unit of this invention includes a defocus detecting system for detecting a defocus of an objective lens, a thickness unevenness detecting system for detecting a thickness unevenness of a transparent resin layer provided nearest the objective lens of a recording medium, and a thickness unevenness correcting mechanism for changing the focusing characteristic of light impinging upon the objective lens based on a change in the thickness of the transparent resin layer detected by the thickness detecting system.

Abstract: An apparatus is provided for disc rotation control in an optical storage system, which is capable of generating a focusing error signal from light that was reflected by a loaded optical disc. The apparatus includes a focus controller for processing the focusing error signal to obtain a focus output signal, a low pass filter unit for processing the focus output signal by low pass filtering to obtain a filtered signal, a direct current level remover for removing a direct current component of the filtered signal to obtain a warp-indicating signal, and a speed controller for comparing the warp-indicating signal with a predetermined threshold value to determine extent of warping of the optical disc. The speed controller is operable to control the optical storage system so as to limit maximum rotation speed of the optical disc according to result of the comparison made by the speed controller.

Abstract: This invention relates to an optical scanning device for scanning an optical record carrier and detecting a tilt characteristic of the optical record carrier during scanning. The device includes a redirecting structure (26) arranged on an objective lens (10) to redirect a part of a radiation beam, when travelling towards the record carrier, differently to a main part of the radiation beam. The redirected beam part follows a path which is different to that of a path followed by the main beam part, towards a position sensitive detector in a detection system (16).

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

Abstract: The invention presents an optical element with which an optical head can be configured, in which there is little deterioration of the correctional effect when the objective lens shifts, as well as an optical head and an optical recording/reproducing apparatus using such an optical element. The invention also presents a novel optical recording/reproducing apparatus and optical recording/reproducing method. The optical element, includes a first voltage application electrode 13, a first opposing electrode 17 arranged in opposition to the first voltage application electrode 13, and a first phase changing layer 15 arranged between the first voltage application electrode 13 and the first opposing electrode 17. By changing a voltage between the first voltage application electrode 13 and the first opposing electrode 17, a phase that converts plane waves into spherical waves is imparted on light that is incident on the first phase changing layer 15.

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: An optical disc drive generates a control signal according to the delay of a TZC signal. The control signal can determine if an optical pickup of the optical disc drive crosses a track. When the optical pickup is reading a defective section of an optical disk, the optical disc drive cannot correct the movement of the optical pickup. Therefore, after the optical pickup passes through the defective section of the optical disc, the optical disc drive adjusts the gain of the tracking drive signal according to the control signal.

Abstract: A method of processing a defect detection signal in a recording and/or reproducing apparatus that records and/or reproduces an optical information storage medium the method including generating a defect detection signal comprising a servo hold pulse from a radio frequency (RF) signal output from an optical pickup unit; and generating an OR signal by performing an OR operation on the defect detection signal and a first pulse signal having a first pulse width. The method further includes generating an AND signal by performing an AND operation on the OR signal and a second pulse signal having a second pulse width.

Abstract: An optical disk apparatus irradiates first and second lights, which are emitted from an identical light source, on a disk-like volumetric recording medium from both sides thereof with first and second object lenses corresponding to the first and second lights, respectively, such that the lights are focused in an identical focal point position and records a standing wave. The optical disk apparatus includes an aberration adding unit that adds complementary aberrations to the first and second lights made incident on the volumetric recording medium, respectively.

Abstract: An optical pickup unit includes a light source emitting a light beam, an objective lens focusing the light beam onto an information recording medium, a light detection part receiving the light beam reflected from the information recording medium, and a light blocking part selectively blocking a part of the light beam with respect to a radial direction. The light blocking part is provided in an optical path of the light beam centered on an optical axis.

Abstract: Since a disc vibrates in a natural mode at a predetermined rotation speed, a variation in a tilt of the disc relative to an optical head is caused. As a result, the read/write performance of a disc drive is deteriorated. The disc drive has a disc tilt database for recording a relative tilt angle of the disc in a tangential direction thereof associated with the disc natural mode and the disc rotation speed at which such tilt occurs, a circuit for detecting a disc rotation speed, and a tilt drive circuit. An objective lens is tilted so that the relative tilt angle is corrected, and thus, stable read/write performance of the disc drive is achieved.

Abstract: An optical disc system and a method of managing shock while recording or playing data in the optical disc system are provided. The optical disc system includes an optical pick-up unit for applying a laser beam to a track of an optical disc and detecting reflected light, a servo unit for controlling tracking and focus of the optical pick-up unit and a monitoring unit for comparing a monitoring signal, which is output from the optical pick-up unit and the servo unit, with a reference signal and generating a blocking signal and a blocking release signal. Recording or playing of data on the optical disc is stopped in response to the blocking signal, and recording or playing of the data on the optical disc is resumed in response to the blocking release signal based on a state of the optical disc system when recording or playing was stopped.

Abstract: An apparatus for generating tracking error signals including: an optical detection unit having a plurality of divided light receiving elements to allow beams reflected from a recording surface of the optical disks to be incident; a comparator for outputting after comparing the signals from light receiving elements, which correspond to the set group of the optical detection unit, with the reference signals set for the each group; an error correction unit for correcting and outputting errors if there are any errors after mutual comparison with signals of the groups output from the comparator; a phase-difference detection unit for outputting the signals for each group that correspond to a phase-difference after mutual comparison of the signals of the groups output from the error correction unit; a subtractor for mutually subtracting the signals for each group from the phase-difference detection unit and outputting the tracking error signals.

Abstract: A disk recorder/player (1) including a skew adjusting means of a thin design is provided which includes a base (101), a disk rotation driving mechanism (102) for an optical disk (4), an optical pickup (103), first and second guide shafts (105, 106) to support the optical pickup (103) at opposite ends of the latter, an optical pickup moving means (104) guided by the first and second guide shafts (105, 106) in moving the optical pickup (103) radially of the optical disk (4), an elastic member (126) put in contact with the first and second guide shafts (105, 106) to force the first and second guide shafts (105, 106) in a direction generally perpendicular to the main side of the optical disk (4), an adjusting screw (127) put into contact with the first and second guide shafts (105, 106) from the opposite side of the elastic member (126) to move the first and second guide shafts (105, 106) in a direction opposite to the direction of forcing by the elastic member (126), and a skew adjusting means (109) which adjust

Abstract: An optical disc drive and a method of controlling the same. The optical disc drive includes: a pickup module to apply a laser beam to a surface of a record layer of an optical disc, and forming a focal point on the record-layer surface; and a servo controller to correct (e.g., iteratively or otherwise) the servo gain to allow a record-servo gain to move along a playback-servo gain of the optical disc. Therefore, the optical disc drive and associated method provide servo-control.

Abstract: An apparatus comprises a lens, an alignment feature positioned adjacent to a surface of the lens, a detector for producing an alignment signal in response to a portion of incident light reflected by the alignment feature and a portion of the incident light reflected by the surface adjacent to the alignment feature, and an actuator for controlling alignment of the incident light in response to the alignment signal. A method of controlling alignment of the beam of incident light is also provided.

Abstract: Laser light is irradiated from a lateral side of an optical disk (2) set in place to a peripheral side face of the optical disk (2), return light from the peripheral side face irradiated with the laser light is detected, and a displacement of the optical disk (2) is measured based on the detected amount of return light. Also, the focus is adjusted in relation to the information recording surface correspondingly to the measured disk displacement. Thus, a displacement of an optical disk can be measured in an extremely simple manner and with an extremely high accuracy, and information can accurately be recorded or reproduced to or from the optical disk with the focus being controlled.

Abstract: An apparatus and a method for compensating periodic signal in an optical disc drive are described. The control apparatus includes an amplitude processing unit, a phase processing unit, and a wave generator. The amplitude processing unit processes the amplitude of the input signal (Sin) based on a reference signal (Sref) for generating an amplitude signal (Sad) wherein the amplitude signal (Sad) has at least one amplitude value (Vad). The phase processing unit processes the phase of the input signal (Sin) based on the reference signal (Sref) for generating a phase signal (Spd) wherein the phase signal (Spd) has at least one phase value (Vpd) during the cycle of the reference signal (Sref). The wave generator generates a compensated wave signal (Scom) based on the amplitude value (Vad) and the phase value (Vpd) during the cycle of the reference signal (Sref), and the wave generator outputs the compensated wave signal (Scom) for compensating the periodic signal of the input signal (Sin).

Abstract: The invention relates to a method and an arrangement for compensating scanning disturbances on optical recording media such as occur in a control loop of a playback or recording unit, in particular as settling amplitude after a disk disturbance and are caused by scratches or dirt on the optical recording medium. In order to compensate the scanning disturbances, a follow-up signal counteracting the settling amplitude is coupled into the control loop as additional offset as a function of the frequency of the occurrence of a disk disturbance for a prescribed time interval. The follow-up signal is coupled into the control loop with a step width that is increased from revolution to revolution on the recording medium until the change in the direction of the settling amplitude of the control loop. Large follow-up signal values are produced in a stepwise fashion in the event of absence of the disk disturbance, in order to avoid large variations in the follow-up signal value.

Abstract: A disk drive apparatus for recording (writing) and/or reproducing (reading) information on an optical disk by rotating the optical disk, and adjusting the tilt angle of an optical pickup device with respect to the optical disk. A spindle chassis rotationally supports a turntable on which the optical disk is placed. A pickup chassis, rotationally supported on said spindle chassis, movably supports an optical pickup device that writes and/or reads the information to/from the optical disk and is movable toward and away from the turntable. A tilt mechanism adjusts the tilt angle of the optical pickup device with respect to the optical disk by rotating the pickup chassis with respect to the spindle chassis.

Abstract: In order to simplify operation control and achieve smaller-sized apparatuses, the present invention provides an object lens drive apparatus having a fixed block, a movable block holding an objective lens, support springs connecting the fixed block and the movable block, a focusing coil, tracking coils, a tilt coil, first magnets constituting a first magnetic circuit, and a second magnet constituting a second magnetic circuit and arranged in a state being inserted in the tilt coil. The objective lens and the second magnet are positioned separately in a direction orthogonal to both a focusing and tracking directions. The second magnet is polarized to an N pole and an S pole parallely in the tracking direction. Portions of the tilt coil opposed to each other in the tracking direction with the second magnet put therebetween are formed to be tilt drive portions moving the movable block in a tilt direction.

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: In an optical disk apparatus for focusing a light beam on a track of an optical disk by using a tracking control loop to perform at least one of recording and reproducing operations upon the optical disk, a loop level calculating unit calculates loop levels of the tracking control loop. A control unit calculates a loop gain of the tracking control loop in accordance with the loop levels of the tracking control loop and compensates for a radial tilt of the optical disk in accordance with the calculated loop gain of the tracking control loop.

Abstract: According to the present invention, it is intended that the recording can be executed normally even against small vibrations to which a servo error signal detecting circuit cannot respond. A recording apparatus according to the present invention includes an optical head (12) for receiving a reflected laser beam (LREF) obtained when a laser beam (LIRR) is irradiated on a CD-R (10). This recording apparatus further includes a gate circuit (31) to which an output signal (SRD) of the optical head (12) is supplied and a level comparing circuit (34) for comparing a value of an output signal (DTAU) of this gate circuit (31) with a predetermined reference value (DTH). Upon recording, the gate circuit (31) is controlled in such a manner that a signal of a predetermined period ts may be outputted from the output signal (SRD) supplied from the optical head (12) to the gate circuit (31) as the output signal (DTAU).

Abstract: An optical disc device of the present invention has a carriage opposed to an optical disc medium and capable of moving in a radial direction of the optical disc medium; a first driving section for driving the carriage; an object lens mounted in the carriage for focusing laser light on the optical disc medium; a second driving section mounted in the carriage for displacing the object lens in the radial direction of the object lens; a lens-position detecting section fixed to the carriage for detecting positional information on the object lens; an eccentricity removing section for generating a position detecting signal by removing an eccentric component of the optical disc medium from the positional information on the object lens; and a displacement detecting section for determining, using the position detecting signal, whether or not the carriage should be driven and for providing an instruction to begin driving the carriage, to the first driving section, based on a result of the determination.

Abstract: An apparatus for recording data on and reproducing data from the disk in which a recording area is divided into sectors, includes a reproducing signal generator for generating a reproducing signal including sum signals V1 and V2 of radial pairs, a sum signal RF_sum, and a push-pull signal RF_pp from an optical signal reflected from the disk, a header area detector for generating a header area signal including a header area from the reproducing signal, a first synchronous signal level detector for detecting a magnitude Ivfo1 of a first synchronous signal in the first header by being synchronized with the header area signal, a second synchronous signal level detector for detecting a magnitude Ivfo3 of a second synchronous signal in the second header by being synchronized with the header area signal, and a balance calculator for calculating the balance of the magnitude Ivfo1 and the magnitude Ivfo3.

Abstract: The method for reproducing records for the optical recording medium detects and compensates for detrack, tilt and defocus, having advantages in that: (1) the magnitude and the direction of detrack, tilt and defocus can be detected from a difference signal (for example, a read channel 2 signal or a tracking error signal obtained by processing the read channel 2 signal) between optical reflecting signals detected at the header fields staggered on the basis of the tract center, and compensates for detrack, tilt and defocus, thereby preventing deterioration of data quality caused by detrack, tilt and defocus during a recording/reproducing operation and enabling the stable operation of the system; and (2) the focus servo is rapidly stabilized to enable real-time recording as well as the stable operation of the system.

Abstract: A disk device in which at the recovery job of a focus pull-in operation, a CPU supplies servo control means with the respective correction values of the rotational speed of an optical disk and the moving speed of a lens which are described in the data table of a RAM, and performs the focus pull-in operation and determines whether or not the focus pull-in operation is successfully performed at the respective adjustment steps, and if the focus pull-in operation is successfully performed, the servo control means changes the amount of movement of the lens in response to a surface swing of the optical disk.

Abstract: An apparatus and a method of playing an optical recording medium, including a method of compensating for a tilt by a real time tilt detection before and during a playing operation of the optical recording medium. A tilt compensating apparatus includes an optical pickup, a tilt adjuster which adjust a tilt of the optical pickup, a jitter detector which detects a jittering amount of a playing signal generated from the optical pickup, and a tilt controller which controls operations of the tilt adjuster so as to have the jittering amount become minimum by comparing the jittering amount detected before a reproduction of a content of the optical recording medium with a first jittering reference value, and comparing the jittering amount detected during the reproducing of the optical recording medium, per a certain period, with a second reference value. Since the reproduction of the optical recording medium is performed after a tilt compensation, it takes a shorter time to start the reproduction operation.

Abstract: An optical head includes the following: a light beam separator (35) that includes substantial interference regions for light that is reflected from an information recording medium and travels in a straight path and ±first-order diffracted light produced by information tracks of the information recording medium, and diffracts each of plural light beams in regions (32a, 32b) of the substantial interference regions, where the amount of light is changed by a change in the relative angle between the information recording medium and the objective lens and by a shift of the objective lens in the radial direction of the information recording medium; a light-receiving element (36a, 36b) for receiving the light beam that is reflected by the information recording medium and separated by the light beam separator (35); and an arithmetic circuit that corrects a value of an electrical signal detected by the light-receiving element (36a, 36b) in accordance with a radial position signal corresponding to the amount of shift of

Abstract: A method and apparatus compensating for disc eccentricity includes extracting eccentricity data from a tracking error signal having one period, generated by a tracking servo, detecting parameter values of an eccentricity component extracted during the extraction of the eccentricity data and transforming a reference sine wave based on the detected parameter values of the eccentricity component. The eccentricity data is replaced with the transformed reference sine wave and the replaced eccentricity data is added to the tracking error signal to compensate for the disc eccentricity.

Abstract: An optical disk apparatus for enabling to suppress the time necessary for alternation process down to the minimum, as well as, for executing the alternation process with certainty, and also an alternation process method for that apparatus, for recording alternation information for a defect block detected within a user data recording area of an optical disk, into alternation areas of the optical disk 100, wherein during recording operation of user data, when detecting a defect block within the user data recording area on the optical disk, after executing the alternation process only on one side of alternation areas provided on both an inner periphery side and an outer periphery side of the optical disk, the alternation process is executed on a remaining alternation area, but after completing the recording operation of the user data.

Abstract: An optical pick-up device comprising at least one micromirror array lens. The micromirror array lens enables focusing, tracking, and/or tilt compensation in the optical pick-up device without macroscopic motions. The micromirror array lens provides the device with a simple structure, which can reduce the size, weight, and cost of the recording/reproducing system. The device is also durable for vibration. Optical pick-up devices using an array of micromirror array lenses can increase the recording/reading speed without macroscopic motions. The recording/reading speed can be increased by adding more micromirror array lenses to the lens array. The present invention can also be used to record/read information on/from a multi-layered optical disc.

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: Tilt of an optical disk is detected and controlled by detecting a tilt zone border based on a zone correspondence table expressing a ZCLV zone of the optical disk and the tilt zone including a border corresponding to the border of the ZCLV zone. The deterioration of accessibility within the ZCLV zone at the time of tilt control is reduced by the tilt zone having a border corresponding to the border of the ZCLV zone.

Abstract: A playback apparatus for reproducing data recorded on a disk medium by using an optical pickup, the playback apparatus comprising: RF signal generating means, data signal generating means, defect signal generating means, focus error signal generating means, focus servo control means, tracking error signal generating means, tracking servo control means, monitoring means, and defect period processing control means for controlling the focus servo control means and the tracking servo control means, wherein the focus servo control means and the tracking servo control means perform defect period processing when a result of the monitoring by the monitoring means indicates the defect period.

Abstract: A tracking offset is reduced. The effect of an SPP signal fluctuation is reduced by using a variable mixing ratio DPP method, and a residual tracking offset is minimized.

Abstract: The present invention discloses a tilt error detecting device for detecting a tilt error signal indicative of a tilt error between an optical disc and an optical pick-up head. The tilt error detecting device includes: a first combining module for generating a first level signal according to a first portion of a plurality of detecting signals which corresponds to a plurality of first detecting areas on a photo detector; a second combining module for generating a second level signal according to a second portion of the detecting signals which corresponds to a plurality of second detecting areas on the photo detector; and a calculating module coupled to the first combining module and the second combining module for generating the tilt error signal according to the first level signal and the second level signal.

Abstract: A tilt sensor 23 is provided on a CD optical pickup 11, and a sub-chassis 24 and a height adjustment mechanism 25 and the like are provided for adjusting the tilt of a DVD optical pickup 12. A recording or reproduction position is read in by the DVD optical pickup 12 while moving the CD optical pickup 11 and the DVD optical pickup 12 along guide shafts 18 and 26 respectively, the amount of tilt of the optical disk 16 at this position is detected by the tilt sensor 23 of the CD optical pickup 11, the tilt of the laser light axis from the DVD optical pickup 12 is adjusted in accordance with the amount of tilt that is detected, and the amount of tilt of the optical disk 16 is corrected.

Abstract: An actuator and a method of operating an optical pickup of an optical disk drive comprises a blade on which an object lens is mounted, a plurality of magnets for generating a magnetic field, a plurality of focusing coils for interacting with the magnetic field generated at the magnets to move the blade in a first direction, a tracking coil for interacting with the magnetic field generated at the magnets to move the blade in a second direction, a first supporting member for supporting the blade so that the blade is tilted by the difference in electromagnetic forces which are generated between the magnets and the focusing coils, and a second supporting member connected to the first supporting member, for movably supporting the blade in the first and the second directions. Accordingly, the blade tilts in the tangential direction by adjusting the electric current supplied to the focusing coil.

Abstract: In a tilt correction method, first information about a specific inclination of an object lens is acquired in response to an access request to an information recording medium. The specific inclination is obtained when the signal characteristic of a push-pull signal becomes a prescribed level in or near a target access area. Then, second information about the optimum inclination of the object lens is acquired for the target access area, based on the first information and tilt difference information representing a difference between a first inclination and a second inclination of the object lens defined in advance in a particular area on the information recording medium. The first inclination corresponds to an optimum reproduced signal from the particular area, and the second inclination is obtained when the signal characteristic of the push-pull signal from the particular area becomes the prescribed level. Finally, tilt correction information is estimated from the second information.

Abstract: An optical disk servo device capable of correcting spherical aberration occurring by thickness errors of a cover layer of an optical disk or disc while avoiding risks of influence by vibrations and shocks or else is disclosed. The device includes an optical head unit for writing or reading information to or from the optical disk, a tracking-servo unit, a lens for correction of spherical aberration, and a lens position detector for detecting a position change amount or displacement of the lens and for generating at its output a lens position detection signal, which is then subjected to negative feedback to the tracking-servo unit.

Abstract: An optical head that detects a tilt in an optical disk. The optical head includes a condensing means, a light receiving means, a tracking error signal detection means, and an optical tilt detecting means. The light receiving means includes at least first and second light receiving areas, the first light receiving area being a rectangle having long sides that extend in a direction perpendicular to information tracks on the optical disk. The tracking error signal detection means detect error signals corresponding to light signals received in the first and second light receiving areas. The optical disk tilt detection means compare the tracking error signals to detect a radial tilt in the optical disk. In an alternative embodiment, the long sides of first light receiving area extend in a direction parallel to the information tracks, and the optical disk tilt detecting means detect a tangential tilt in the optical disk.