Abstract: A tilt correcting apparatus makes a tilt correction in an information recording apparatus or the like capable of recording record information onto an information recording medium, on an information recording surface of which a track having a wobble is formed, by emitting laser light thereonto. The tilt correcting apparatus is provided with: a correcting device for changing an irradiation angle of the laser light; a controlling device for controlling the correcting device such that the irradiation angle is set to be each of a plurality of predetermined angles before the record information is recorded; a wobble detecting device for detecting a wobble signal corresponding to the wobble from a photo-detection signal of light from the track caused by the laser light; and a tilt determining device for determining an amount of tilt of the information recording surface, on the basis of the detected wobble signal.

Abstract: An information recording apparatus (300) is for recording record information onto an information recording medium (100) comprising a first recording layer (L0 layer) and a second recording layer (L1 layer) to record therein the record information by irradiating laser light. The information recording apparatus is provided with: a recording device (352) for recording the record information into at least one of the first recording layer and the second recording layer by irradiating the laser light; and a controlling device (354) for controlling the recording device to record the record information into a target area (115a), which is a recording area of the second recording layer corresponding to a recording area (105a) of the first recording layer in which the record information is recorded, if the record information is recorded into the second recording layer.

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.

Abstract: An example hologram recording/reproduction device reproduces recorded information from a holographic recording medium where interference fringes formed by a reference light and an object light corresponding to the recording information are recorded. The example hologram recording/reproduction device irradiates the reference light to a holographic recording medium; generates detection information data (Ddet) according to the detection light generated by irradiation of the reference light; sets a target irradiation position of the reference light on the surface of the holographic recording medium according to the detection information data; and moves the irradiation means with respect to the holographic recording medium along its surface so that the reference light is irradiated to the target irradiation position.

Abstract: A warpage angle measurement apparatus and a warpage angle measurement method are provided that can measure an angle of warpage of an optical disc and a cartridge for the optical disc caused by a rapid environmental change such as a temperature change or a humidity change in a short time. The warpage angle measurement apparatus 10 includes: a constant temperature chamber 22 for accommodating an optical recording medium 20 formed by mounting the optical disc 16 as an object to be measured in the cartridge 18 and for adjusting a surrounding of the optical recording medium 20 to have a predetermined environmental condition; a laser oscillator 24 for causing laser oscillation to emit laser light to the optical disc 16; and a light-receiving unit 26 for receiving the laser light reflected from the optical disc 16 and detecting a relative angle of an optical path L2 of the reflected laser light with respect to an optical path L1 of the emitted laser light.

Abstract: An optical disc drive apparatus includes: a laser beam source; a collector device disposed as facing a disc that can record a signal, which collects a laser beam emitted from the laser beam source onto the disc; a record processing module which records the signal on the disc through the collector device while modulating laser power of the laser beam source; a reflecting light level detecting module which receives the reflecting light when the signal is recorded and detects a level of the reflecting light; a laser power control module which controls the laser power when the signal is recorded based on the detected level of the reflecting light; a tilt control module which controls a tilt angle between the disc and the collector device based on the detected level of the reflecting light; and a switching module which switches between control of the laser power and the tilt angle.

Abstract: There are provided an optical disk device and tilt correction processing method for performing recording/reproduction by rapidly acquiring an optimal tilt correction value for an optical disk having a plurality of recording/reproducing layers. In an optical disk device capable of recording or reproducing information by irradiating a laser beam to each of a plurality of recording/reproducing layers of an optical disk, the tilt value is stepwise set within a predetermined range at a predetermined radius position of the recording/reproducing layer located at the farthest distance from the laser beam irradiation side so that an optimal tilt correction value can be obtained from the quadratic function by the method of least squares of the jitter or the like obtained from the disk. By applying the optimal tilt value obtained to the other recording/reproducing layer, it is possible to start recording or reproduction in a short time.

Abstract: When the tilt of an optical disk is detected using a light source of an optical head, the optical head cannot be simplified enough and an optical-disk tilt cannot be detected adequately. The optical head includes: an LED chip; a light-converging element that converges the light which is emitted from the LED chip upon an optical disk; a light-converging element driving means which drives the light-converging element; and a sensor which detects a tilt or a positional shift of the optical disk. In the sensor, the LED chip is placed on a semiconductor substrate which is provided with a plurality of light-receiving chips; the light emitted from the LED chip irradiates the optical disk; the light which is reflected from the optical disk is received by the plurality of light-receiving chips; and based upon the quantity of light which is received at the plurality of light-receiving chips, a tilt or a positional shift of the optical disk is detected.

Abstract: An optical disk device that has a tilt correction unit for performing tilt correction to incline the optical axis of laser light based on a tilt between the recording layer of an optical disk and the optical axis of said laser light. The tilt is detected when the optical disk is activated. The optical disk device has a memory for storing a difference in temperature in accordance with the amount of the detected tilt. The difference in temperature is utilized for updating the tilt. The optical disk device engages said tilt correction unit to update said tilt, when a difference in temperature between activation of said optical disk and writing/reading information onto/from said optical disk is detected and when the detected difference in temperature has exceeded the stored difference in temperature corresponding to the amount of the detected tilt.

Abstract: The invention relates to a tilt controller for controlling the tilt (radial and/or tangential) of an actuator relative to a recording surface of an optical storage medium, compensation for the radial to tilt crosstalk being effected by feeding a filtered version of the radial control signal (r) into the tilt branch, and/or compensation for the focus to tilt crosstalk being effected by feeding a filtered version of the focus control signal (f) into the tilt branch.

Abstract: An optical recording-reproducing apparatus comprises a laser beam source; an objective lens for focusing a laser beam from the laser beam source on a disk medium; an actuator for positional control of the objective lens; a tilt-compensating mechanism for adjusting inclination of the objective lens relative to the disk medium; a detecting element for detecting an amount of a change of the power of the laser beam for recording of information on the disk medium, wherein the tilt-compensating mechanism adjusts inclination of the objective lens according to the amount of the change of the power of the laser beam when the recording is carried out.

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 optical pickup actuator, including a lens holder movably installed on a base, and mounted with an objective lens to transmit an incident light to an optical information recording medium, and a magnetic circuit to independently drive the lens holder in a focusing direction, a tilting direction and a tracking direction, respectively.

Abstract: An optical scanning device for scanning a record carrier (22), the record carrier has an outer face (24) and the optical scanning device comprises a radiation source system (2) arranged to generate a radiation beam; an objective system (20) having an exit face (76) and which is arranged between the radiation source system and the record carrier and provides for evanescent coupling of the radiation across a gap between the exit face of the objective system and the outer face of the record carrier; and a radiation detector arrangement for detecting radiation after interaction with the record carrier. The radiation detector arrangement is arranged to produce a tilt error signals (?, ?) representing a tilt misalignment between the exit face of the objective system and the outer face of the record carrier.

Abstract: Embodiments of a method and apparatus for controlling tilt in an optical disc device such as a DVD recorder can select dynamic tilt control mode if the current operating mode of the device is record mode, and select static tilt control mode if the current operating mode is play mode thereby enabling tilt control selected for the current operating mode. Further, the device can maintain dynamic tilt control mode when data recording is resumed after being suspended, which enables the device to quickly perform tilt control preferred for the current optical pickup location. The device also can check the type of optical disc and whether a host supports defect management to select a preferred tilt control mode.

Abstract: An optical pickup device comprising at least a light source, an optical unit for irradiating an optical recording medium with a plurality of lights from this light source, a head unit located in an opposing relation to the optical recording medium and converging a plurality of lights emitted from the light source on a recording surface of the optical recording medium as near field light, a photo-detecting unit for detecting an angle between the head unit and the recording surface of the optical recording medium based on quantities of returned lights from the optical recording medium and a tilt control unit for controlling the tilt driving unit based on an angle detected by the photo-detecting unit so that an angle of the head unit relative to the recording surface is held constant. Then, an optical pickup device, an optical recording and reproducing apparatus and a tilt detection method are able to automatically control a tilt without requiring setting up an external sensor independently of an optical pickup.

Abstract: [Problems] To effectively perform optimal tilt adjustment. [Means for Solving the Problems] A tilt adjusting method adjusts a tilt angle of an actual incident light and reflected light with respect to an incident light and a reflected light under optimal tilt when recording and reproducing data onto/from an information recording medium. Two or more output signals having a balance between a signal component and a noise component changing with respect to a parameter of a correction object are extracted from the reproduction signal of the information recording medium and the signal component and the noise component are evaluated for performing signal correction, thereby calculating a first and a second coefficient. When the first coefficient is out of a set reference range, the tilt adjustment is performed by the first coefficient and when the first coefficient in the set reference range, the tilt adjustment is performed by the second coefficient.

Abstract: A tilt sensor for detecting information related to a tilt of an object to a reference plane is disclosed. The tilt sensor includes a diffraction element disposed that diffracts an incident light at diffraction efficiency depending on the incident angle, and a photo detector that detects a diffraction light diffracted by said diffraction element and outputs an photoelectric signal. Since the diffraction efficiency of the diffraction element changes as the incident angle changes, the intensity of the diffraction light from the diffraction element changes. As a result, the photoelectric signal output from the photo detector contains the information related to the tilt of the object.

Abstract: An optical recording medium tilt compensation device having a tilt compensation unit is disclosed that is able to compensate for a tilt error in servo control when recording or reproducing data in an optical recording medium.

Abstract: A tilt amount detector includes inputting means for inputting a reproduction signal supplied from an optical disc, a first filter portion and a second filter portion for correcting an optical transfer characteristic of the reproduction signal, a reference clock extracting means for extracting a reference clock signal from the input reproduction signal, a first jitter meter and a second jitter meter for measuring jitter amounts of output signals from the filter portions and the extracted reference clock signal and outputting the measured jitter amounts, and a difference calculating means for calculating a difference between the jitter amount measured by the first jitter measuring means and the jitter amount measured by the second jitter measuring means.

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 a ? value is detected from an RF signal that is played back. When a signal is recorded for which the detected ? value 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: In a near-field optical recording/reproducing system and a method of controlling a tilt, the near-field optical recording/reproducing system includes: a light source; an objective lens to focus light emitted from the light source to transmit near-field light to an information storage medium; a PD (photodetector) to receive a portion of the light that is transmitted from the objective lens to the information storage medium and is reflected from the information storage medium, to detect a GES (gap error signal) used for controlling an air gap formed between the objective lens and the information storage medium; a signal processor/determiner to obtain an edge voltage using the GES detected by the PD and determine a tilt control point using the edge voltage; and an adjuster to control a relative tilt between the objective lens and the information storage medium in the tilt control position.

Abstract: An optical pickup includes a lens holder body having a first surface and a second surface opposing to each other, tracking coils, a focusing coil, and tilt coils which are formed on a pair of flat panels respectively disposed on the first and second surfaces, and first and second magnetic bodies respectively disposed to face the first and second surfaces of the lens holder body and each constituting a planar closed magnetic circuit.

Abstract: A tilt detecting apparatus is provided with: a first changing device for changing a focus position of laser light in a lamination direction of recording layers; a second changing device for changing the focus position in a radial direction of the information recording medium; and a tilt detecting device for detecting an amount of tilt, on the basis of a photo-detection signal. Its controlling device controls the first changing device to set the focus position onto one recording layer, controls the second changing device to displace the focus position to a j-th radial direction position (wherein j is a natural number) on the information recording medium, and controls the tilt detecting device to detect the j-th amount of tilt for the one recording layer.

Abstract: A multi-layer data storage medium includes a plurality of recording layers in which a guide groove, where data is stored, is formed in a spiral manner, and each center of the plurality of the recording layers is eccentric to a center of the multi-layer data storage medium in a different direction.

Abstract: An optical disc player for recording/reproducing data on an optical disc, including an optical pickup unit emitting a laser beam to the surface of the optical disc and extracting an RF signal corresponding to the recorded data, a signal size computing unit computing an envelope size of the RF signal, a tilt adjuster adjusting a tilt of the optical disc, and a controller for designating the tilt at a maximum envelope size as an optimal tilt, and controlling the tilt adjuster to change a present tilt based on the optimal tilt. Similarly, it is also possible to designate an optimal skew based on the skew at a maximum envelope size. Accordingly, embodiments of the present invention make it possible to obtain the optimal tilt/skew using the RF envelope.

Abstract: An optical pickup device comprising: a tilting mechanism for tilting an objective lens in accordance with tilt of an optical information disc disposed above the objective lens; a wavelength-selecting opening-regulating filter disposed immediately below the objective lens and moving integrally with the objective lens; and a turning mirror for guiding light beams from a light source toward the opening-regulating filter, wherein a stopper for regulating an amount of downward movement of a holder for holding the objective lens and the opening-regulating filter is provided in the vicinity of a plane including the axis of tilting operation of the tilting mechanism and center of the objective lens and at substantially the same height level as that of the opening-regulating filter, and at least one of the opening-regulating filter and the turning mirror has a contact avoiding part for avoiding contact between the opening-regulating filter and the turning mirror.

Abstract: An optical disk recording and reproducing apparatus includes a focus unit that focuses an irradiation light beam on an optical disk having data recording layers and tracks; a drive unit that changes a direction of the beam by moving the focus unit; a tilt control unit that detects a tilt amount of the optical disk, computes a control operation amount in a band wider than a rotation frequency of the optical disk based on the tilt amount, and controls the drive unit to move the focus unit based on the control operation amount. The tilt control unit holds a control state of the control at an immediate pre-state of an inter-layer jump in which the beam is moved to a different data recording layer or a track jump in which the beam is moved to a different track during the inter-layer jump or the track jump.

Abstract: An optical disc drive apparatus includes a rotatably supporting drive unit supporting an optical disc, an optical pickup, an angular velocity sensor detecting the magnitude and direction of an angular velocity, a skew estimating section estimating disc skew from the result of detection by the angular velocity sensor, such that one estimated skew value in a case where the angular velocity is applied in a direction in which the optical disc moves away from the optical pickup differs from another estimated skew value in a case where the angular velocity of the same magnitude but in the opposite direction, in which the optical disc approaches the optical pickup, is applied, and a tilt drive section changing the tilt of the light beam in accordance with the estimated skew value and correcting a shift, occurring because of the angular velocity, in a light beam applying position on the optical disc.

Abstract: An optical disc apparatus, and a method of driving the same, includes a light focusing element disposed to focus light emitted from a light source onto a disc; an actuator to move the light focusing element toward or away from the disc according to a voltage applied to the actuator; a light intensity detection unit to detect the intensity of light reflected from the disc ; a servo unit to generate a gap error signal and a third voltage, the third voltage being the sum of a first voltage and a second voltage, and to apply the generated third voltage to the actuator; and a control unit to control the servo unit to perform a gap pull-in operation when the light focusing element is moved toward the disc according to the gap error signal and the third voltage.

Abstract: A method and apparatus for controlling the tilt between the optical axis of an optical pick-up head and an optical disc applied in an optical disc drive is provided. A trapezoidal-wave signal in a radio frequency signal is received, wherein the trapezoidal-wave signal includes a rising edge and a falling edge. And a slope sum is calculated and so is an amplitude or a time domain area of the trapezoidal-wave signal. Then, a tangential tilt control parameter is generated according to the slope sum, and a radial tilt control parameter is generated according to the amplitude or the time domain area of the trapezoidal-wave signal. Thus, the optical disc drive is controlled according to the tangential tilt control parameter and the radial tilt control parameter for the optical axis of the optical pick-up head to be perpendicular to the optical disc.

Abstract: An apparatus for scanning a track on a record carrier has a head for scanning the track and generating a read signal. The tilt between the head and the record carrier (11) is compensated via a tilt servo loop. Thereto the head is provided with tilt compensating actuators (42). A measure of the tilt is jitter in the read signal generated by a front end (43) and filter (44). A wobble generator (40) provides a wobble signal to the actuators and to an input of multiplier (45) for synchronous detection of the jitter. The output of the multiplier (45) is coupled to a low pass filter (46) for generating a tilt error signal coupled to a tilt controller (47) for generating a tilt control signal.

Abstract: A pick-up angle adjustment apparatus in provided for adjusting an angle of an optical pick-up mounted in an optical disk apparatus. In the pick-up angle adjustment apparatus, a first guide shaft has a first length between a pair of ends thereof for guiding and supporting the optical pick-up. A second guide shaft has a second length between a pair of ends thereof for guiding and supporting the optical pick-up. A first adjustment member is operable for vertically moving one end of the first guide shaft so as to adjust the angle of the optical pick-up. The first adjustment member is capable of moving the one end of the first guide shaft by a first distance when the first adjustment member is operated by a given operation amount. A second adjustment member is operable for vertically moving one end of the second guide shaft so as to adjust the angle of the optical pick-up.

Abstract: A method and apparatus for compensating tilt. The tilt compensation method includes: obtaining one of a jitter best, an RF envelope, and a focus DC offset (FODC) from a detection signal of the ROM data region and determining whether the obtained value is within a tolerance range; and obtaining an initial skew compensation value using the obtained value when the obtained value is within the tolerance, changing the magnitude of current applied to an actuator designed to perform driving in at least three-axis directions to drive an objective lens of an optical pickup assembly in a radial tilt direction when the obtained value is not within the tolerance range, and repeating the obtaining of one of the jitter best, the RF envelope, and the FODC and changing the magnitude of the current until the obtained value is within the tolerance range.

Abstract: An optical disk apparatus detects a predetermined tilt angle and a predetermined focus bias at least two detection points on an inner and an outer circumferences of the optical disk. On the basis of the predetermined tilt angle detected at the detection points, the apparatus estimates the predetermined tilt angle at a radial position of the optical disk, and also estimates a focus bias. The apparatus controls the tilt angle according to a radial position of target track and a focus bias on the basis of estimation results at the time of recording and reading data on the optical disk.

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: Disclosed is a tilt controlling method and apparatus in which an FE signal track at a point where an RF signal is the maximum or an RE signal track at a point where a jitter is the minimum is detected as a tilt control signal to induct a DC component according to the disk shape and an AC component according to the surface vibration of the disk. Further, the fact is used that an RF envelope has a maximum value when the disk is parallel to an object lens or there is no tilt. Thus, in a tilt initialization step, a tilt track as the RF Max. is obtained for one rotation and the central potential of this track is set as a tilt control reference voltage, and when the RF envelope becomes a phase corresponding to a condition of a controller or a differential value of the RF envelope in the tilt window signal becomes a desired phase, tilt control is started so that the RF envelope always has the maximum value.

Abstract: An optical disk apparatus includes an objective lens that condenses light on an information recording layer of an optical disk that has a first area with a first track pitch and a second area with a second track pitch, to form an optical spot. The apparatus also includes a tilt driver that inclines the objective lens; a positioning unit that positions the optical spot on a target track; a position error detector that detects a position error of the optical spot from the target track; a tilt detection correcting unit that calculates a tilt error signal based on a first position error detected when the optical spot is positioned on a target track in the first area and a second position error detected when the optical spot is positioned on a target track in the second area; and a tilt controller that controls an inclination based on the tilt error signal.

Abstract: A disk motor which rotationally drives an optical disk; a rotational phase detector which detects a rotational phase thereof; an optical head having a collecting lens which collects an optical bean; a light detector and an LE signal generator which detect a position of the collecting lens in the optical head as a position signal; an LE signal memory recorder and an LE signal memory which store, in synchronization with a rotational phase to be detected by the rotational phase detector, the positional signal from the LE signal generator; an LE signal memory regenerator which outputs as a correction signal, in synchronization with a rotational phase to be detected, the positional signal which has already been detected; a subtractor; an LE signal filter, a drive circuit and a Tk actuator which move the collecting lens using a signal from the subtractor; and a low pass filter which reduces a high-frequency component of the correction signal are provided.

Abstract: A device is arranged for scanning an optical record carrier (11), which has a data layer with parallel data tracks. The device has an optical head (22) comprising a detector for receiving radiation reflected from a data track, the detector having sub-detectors arranged in a quadrant. The device has a tilt unit (32) for generating a tilt signal representing a tilt angle (204) between an optical axis (202) of the optical head and a perpendicular (203) of the data layer. The tilt unit (32) generates a diagonal push-pull signal based on a difference of a first signal of a first diagonally positioned pair of sub detectors and second signal of a second diagonally positioned pair of sub detectors, and processes the diagonal push-pull signal for generating the tilt signal.

Abstract: A method is used for adjusting a tilt of an optical pickup head. The method includes: identifying initial coordinates of the first static spot, the second static spot, and the dynamic spot in an image generated from three reflected light beams from the optical pickup head; turning one of the adjustable screws a predetermined calibrated rotation angle; recording current coordinates of the first static spot, the second static spot, and the dynamic spot in another image generated from three reflected light beams from the optical pickup head; calculating a total needed rotation angle of the one adjustable screw according to the initial coordinates, the predetermined calibrated rotation angle, and the current coordinates; and turning the one adjustable screw a remaining rotation angle computed by subtracting the predetermined calibrated rotation angle from the total needed rotation angle. An adjusting system is also disclosed.

Abstract: A tilt detection apparatus for a medium comprises a tilt detection beam generator that makes a tilt detection beam incident ion a medium to detect whether the medium is tilted with respect to a reference position; a light reception unit that receives the tilt detection beam that after striking the medium, has come from the medium; and a correction output unit that outputs a signal to correct a tilt of the medium, based on a difference in light reception position on the light reception unit between a position at which the light reception unit receives the tilt detection beam and a position at which the light reception unit is to receive the tilt detection beam when the medium is in the reference position.

Abstract: A method and device for measuring the tilt in an optical disc drive (1) is disclosed. The optical disc drive (1) comprises two lasers (31, 41) generating two laser beams (32, 42) having mutually different optical characteristics. One of these laser beams (32) is continuously ON, and is used for writing or reading data to or form the disc. The other laser beam (42) is repeatedly switched ON and OFF. Tilt is measured by comparing a normalized error signal (RES(ON)) during the ON-phase (TON) with a normalized error signal (RES(OFF)) during the OFF-phase.

Abstract: In a method of obtaining a reproduction signal with good quality from a data recording medium, two actual signals are generated as first and second signals I1 and I2 from detection signals obtained from the data recording medium. A coefficient k which has linear correlation with a tilt is calculated based on the first and second signals I1 and I2. A reproduction signal in which influence of the tilt is eliminated, is reproduced by using the coefficient k and the first and second signals I1 and I2.

Abstract: A method and an apparatus of adjusting the tilt-angle of the lens in the optical pick-up head. The apparatus includes a position detecting unit for detecting a position deviation of the lens against the sled, a parameter generating unit for generating a tilt control parameter according to the position deviation, and a tilt control unit for controlling the lens according to the tilt control parameter so that the lens maintains horizontal with reference to the sled.

Abstract: An electronic apparatus with level detecting capability has an electronic component, a light-sensing device for sensing light, a light source for emitting light onto the light-sensing device, a light blocker for blocking light emitted by the light source from projecting onto the light-sensing device when the electronic component is tilted and has a tilt angle within a predetermined range, and a control circuit electrically connected to the light-sensing device for controlling the electronic component to selectively operate in one of a plurality of operating modes according to the intensity of light received by the light-sensing device.

Abstract: A tilt detection system includes an optical disk having a series of data recorded therein, the series of data having a pulse width smaller than the minimum pulse width of data recorded in an ordinary optical disk; a reproducing part reproducing a signal from the optical disk by emitting a light beam onto the optical disk; and a tilt detecting part detecting a tilt of the light beam with respect to the optical disk based on a reproduced RF signal provided by the reproducing part when the series of data having the smaller pulse width is reproduced.

Abstract: A method for controlling a tilt servo in an optical disc device is provided. The method includes (a) detecting a specific signal associated with a focus servo, and (b) generating a tilt servo control signal for an objective lens according to a variation amount of the specific signal.

Abstract: For optical data storage applications a near field optical system can be used. In near field optical systems an accurate control of the distance between the solid immersion lens and the disc surface is crucial. After the correction of a tilt between the lens and the disc, the laser beam may not always be parallel to the optical axis. This has a detrimental effect on the gap signal used for the distance control. The optical head of the invention comprises a gap signal correcting unit to take care of such detrimental effects.