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: An optical disk unit includes the following: a storage part temporarily storing data to be written to an optical disk; a processing part processing the data; an encoder part modulating and outputting the processed data; a writing control part controlling writing of the data to the optical disk; and a writing command part detecting an occurrence of a state of suspension of supply of the data to the storage part and providing an operation command to the writing control part in accordance with the detection result. In the case of suspending the writing of the data to the optical disk, the writing control part causes the processing and encoder parts to stop accessing the storage part by setting the processing and encoder parts in a wait state after the processing and encoder parts access the storage part, and causes the storing of the data in the storage part to be stopped.

Abstract: Technology for sampling optical disc data are described. A first sync tag signal and a data signal are provided, and the previous first sync tag signal is saved as a second sync tag signal. Then, the value of the first sync tag signal and the second sync tag signal are determined to be true or false so as to divide the data signal. Since the neighboring sync tag signals are detected simultaneously, and the timing for sampling the data in the frame is determined according to whether the two contiguous sync tag signals are true or false, the technology can reproduce optical disk data accurately.

Abstract: The present invention provides a method of managing a defective area of an optical disc recordable at high speed, recording/reproducing method thereof, and recording/reproducing apparatus thereof, by which an accurate decision of the defective area is provided. Moreover, as optimal recording speed is applicable to re-recording in a specific section, thereby enabling to secure high reliance of data. In an optical disc provided with a defect management area for defect management within a high-speed recordable disc, the present invention includes verifying whether the defective area is generated in performing a recording at high speed, re-verifying presence or non-presence of defect of a corresponding area by changing a recording speed into low speed if the defective area is generated at the high speed, and recording to manage in the defect management area a location information of an area decided as the defective area at the high speed but as a non-defective area at the low speed.

Abstract: A method of detecting optical disc error information on an optical disc, for applying in an optical disc drive, the method comprising: first, detecting whether the optical disc is blank, if not, perform the following: checking whether a seek error occurred, if yes, recording a seek error mark; while reading a data region, recording data error information, the data error information comprises an error count, and a corresponding data error location; finally, outputting the optical disk error information according to the data error information and the seek error mark.

Abstract: An information recording device is used for recording record information in an information recording medium at least including a first recording layer capable of forming a first recording area and a second recording layer capable of forming a second recording area. The information recording device includes: write elements; acquisition elements for acquiring offset information indicating a relative shift; calculation elements for calculating an address (“Y?=Inv Y??”) indicating a second boundary point opposing to a first boundary point according to the offset information; and control elements for controlling the write elements so as to write record information (i) while making the first boundary point a recording end or start position and (ii) making the second boundary point indicated by the calculated address a recording start or end position.

Abstract: Information recording and playback apparatus, content management method, and content management program. When data of copyright-protected content is recorded in a general-purpose HDD, illegal copying of the content is prevented. Each time when content is recorded in the HDD and when content recorded in the HDD is moved to a Blu-ray disc (BD), a random number output section outputs unique verification information (a random number) and overwrites the unique verification information in the corresponding verification files of the HDD and an EEPROM. Then, when the content recorded in the HDD is to be moved to the BD, a verification section verifies the verification information (random number) recorded in the verification file of the HDD against the verification information (the random number) recorded in the verification file of the EEPROM, and permits the movement of the associated content only when they match.

Abstract: An apparatus which stabilizes an operation of a disc driver in a mode conversion setting section includes a pickup which reads information from a disc that is inserted into the disc driver, a filter which performs a low-pass filtering of a servo error signal that is generated during an operation of the pickup, a selector which selects one of the servo error signal and the low-pass filtered servo error signal from the filter and outputs the selected servo error signal to drive the pickup using the selected servo error signal, and a control signal generator which generates a signal to control the selector to select the low-pass filtered servo error signal in a mode conversion setting section of the disc driver. Accordingly, a defocus and a detrack can be prevented in the mode conversion setting section of the disc driver.

Abstract: An optical storage device capable of operating when abnormal, includes: a control unit for controlling operations of the optical storage device; and a sensor coupled to the control unit, where in a normal mode of the optical storage device, the control unit triggers the start-up or stop of a procedure through the sensor. The control unit is capable of controlling the optical storage device to enter an abnormal mode, and triggering the start-up or stop of the procedure in the abnormal mode according to whether the procedure times out or according to a user command.

Abstract: An apparatus including a first engaging portion for holding an optical pickup, a second engaging portion to be engaged with the first engaging portion, a transfer portion for driving the second engaging portion to transfer the first engaging portion in a radial direction, a calculating portion for calculating a backlash value between the first and second engaging portions in a transfer direction of the first engaging portion, and a driving control unit. The driving control unit controls a driving portion to transfer the optical pickup based on a calculated backlash value.

Abstract: A tracking error signal detection device employing a differential phase detection method includes first and second differentiators which remove direct current components in first and second signal groups in which a phase difference between the first and second signal groups changes in accordance with a tracking error signal, and which differentiate the first and second signal groups, first and second analog/digital converters which sample and quantize signals output from the first and second differentiators, respectively, a Hilbert transformer performing a 90-degree phase shift on one of signals output from the first and second analog/digital converters, a delay circuit delaying one of the signals output from the second and first analog/digital converters by an amount of delay equal to that caused by the Hilbert transformer, and a phase comparator calculating a phase difference between a signal output from the Hilbert transformer and a signal output from the delay circuit.

Abstract: There is provided an apparatus capable of switching between a laser that emits light having a wavelength suitable for detecting samples and a laser required for reading traced data, while an analysis optical disc is being traced. In an analyzer in which an analysis disc having a sample to be analyzed which is located in a part of its track is irradiated with laser light to read the state of the sample, a selector switch alternately selects a laser having a wavelength for reading data represented by bits or wobble grooves on the disc and a laser having a wavelength suitable for detecting a sample, in response to an instruction from a control unit.

Abstract: A recording method for recording, on a write once type information recording medium, management information representing a recording state of the write once type information recording medium is provided. The information recording medium includes data including a first synchronization signal. The information recording medium has a second synchronization signal pre-recorded by cutting. The recording method includes the steps of (a) performing a recording operation for recording the management information at a predetermined position of the information recording medium based on the first synchronization signal; (b) determining whether the recording operation in step (a) is normally terminated or not; and (c) when the recording operation in step (a) is not normally terminated, performing a recording operation for recording the management information at the predetermined position of the information recording medium based on the second synchronization signal.

Abstract: With an object of executing excellent finishing processing when information is recorded to a rewritable type record medium or a write once type record medium, the finishing processing is switched by whether a kind of a medium for recording information is the rewritable type record medium or the write once type record medium and a method of executing the finishing processing is switched based on a state of supplying power.

Abstract: An information carrier apparatus for accessing an information carrier having at least one track formed therein includes a times crossed detection section for detecting the number of times that a head structured to access the information carrier has crossed the track; an eccentricity direction detection section for detecting an eccentricity direction of the information carrier based on the number of times; an eccentricity distance detection section for detecting an eccentricity distance of the information carrier based on the eccentricity direction and the number of times; and an eccentricity correction section for correcting eccentricity of the information carrier based on the eccentricity direction and the eccentricity distance.

Abstract: An environmental load information of an information recording medium is recorded on the information recording medium so as to recycle or dispose properly an information recording medium, which is not necessary any more. The information recording medium comprises a main information area (102) for recording or reproducing information and a recording area (101) for environmental load information, which is recorded with an environmental load information of the information recording medium.

Abstract: In an information recording medium recording method, recording is interrupted, in recording on an information recording medium, when a predetermined interruption condition is met. A signal recorded in a recorded area is played back and a recording signal playback waveform signal is obtained. Error information indicating an error between a reference waveform signal derived by partial response equalization of a data string and the recording signal playback waveform signal is obtained. A recording condition is corrected on the basis of the error information. A recording/playback apparatus and information recording medium are also disclosed.

Abstract: A system and method for calibrating a recording track offset of an optical storage device accessing an optical storage medium of land/groove type. The system includes: a tracking servo loop arranged to control tracking operations of an optical head of the optical storage device; a track offset control loop arranged to control the recording track offset for the tracking servo loop; a controller arranged to enable a latest value of the recording track offset to be a readout value for utilization in a recording process performed later; and a comparator arranged to compare a recording length with a threshold value and generate a flag to represent whether the recording length is a long recording length, wherein the latest value is derived from the track offset control loop.

Abstract: A digital video recorder writes data on a selected one of a first storage medium and a second storage medium. The recorder includes an abnormal state detector for detecting any abnormal event that possibly occurs while the recorder is writing the data on the first storage medium. If the abnormal state detector senses the abnormal event while the recorder is writing the data on the first storage medium, then the recorder stops writing the data on the first storage medium and starts writing the data, which should have been written on the first storage medium only, on the second storage medium instead.

Abstract: An information reproduction apparatus and method according to the present invention are provided so as to solve the problem that signal quality is degraded in a normal signal part when always performing a correction of a transient in reproducing information recorded in a medium, and the sag cancellation controller (103) detects whether the pickup output signal (S101) is normal or abnormal, and the sag cancellation part (104) performs a correction of a transient only during a period when the pickup output signal (S101) is detected as abnormal, thereby preventing degradation of signal quality, which is caused by performing a correction of a transient on a normal signal part, and an appropriate correction of a transient can be performed on an abnormal signal part, thereby enabling a stable reproduced signal (S104) to be obtained.

Abstract: An information recording and reproducing apparatus records data on and reproduces data from each of a plurality of recording layers of a recording medium. A controller (7) controls a formatting process to format the recording medium (1) by performing a first formatting process on the data area of a recording layer. The first formatting process comprises formatting the data area in a series of recording increments that progress from the inner side of the data area to the outer side of the data area. Within each recording increment the formatting is performed along a path extending from the outer side of the data area to the inner side of the data area. A second formatting process on the data area of another recording layer once the first formatting process has been completed, the second formatting process being performed along a path extending from the inner side of the data area of the other recording layer to the outer side of the data area of the other recording layer.

Abstract: Disclosed is electronic equipment enjoying improved ease of use, and a highlighting method and a program to be implemented or installed in the electronic equipment. For example, a user performs manipulations so as to reproduce a content up to the middle of the content, and then turns off a power supply. When the user turns on the power supply next, a playback selection menu screen image is displayed and “Playback from the middle thereof” is highlighted. Consequently, when the user wants to reproduce the content from the middle of the content, the user need not worry about whether to reproduce the content from the beginning or the middle thereof. The user should merely finalize the highlighted item. This would prove user-friendly and helpful. When the electronic equipment is used outdoors or the like, the number of manipulations to be performed on the equipment is smaller than the number of manipulations conventionally performed.

Abstract: The present invention comprises an illumination unit for applying illumination light to the recording medium after recording on a recording medium and a camera unit for picking up an image recorded on the recording medium to which the illumination light is applied by the illumination unit and outputting detected information. The present invention outputs reference detection information obtained by detecting a reference recording image by the camera unit after recording the reference recording data on the recording medium as input recording data, generates correction information by comparing the reference detection information with the reference recording data and generates corrected input recording data obtained by correcting the input recording data on the basis of the correction information, and also detects poor recording on the comparison result between the input recording image information and the corrected input recording data after recording the input recording data on the recording medium.

Abstract: A method of verifying defect management area (DMA) information of an optical disc upon initialization without certification, and a test apparatus for performing the same. The method includes generating as test information, defect management information, which is generated after performing initialization without certification on a blank test disc to which no data is written, and verifying the test information using reference test information for the initialization without certification to provide a test result. Accordingly, it can be easily verified that a recording and reproducing apparatus properly translates and processes DMA information which is generated after initialization without certification, using a blank test disc.

Abstract: A disc apparatus comprising: a jitter-value detection unit configured to detect a jitter value based on a signal to be read from a medium; a defocus-value setting unit configured to set a defocus value for focusing an objective lens in the medium based on the jitter value; and a defocus-value adjusting unit configured to detect the jitter value every time the defocus value is changed stepwise within a predetermined range of the defocus value including a reference value of the defocus value, to obtain an optimum defocus value to be set for the defocus-value setting unit within a predetermined time period, based on a maximum jitter value and a minimum jitter value of the detected jitter values.

Abstract: An aberration detection device of the present invention is such that an absolute value of detection sensitivity of an aberration error signal is increased, and variation in detection sensitivity of the aberration error signal is little even when displacement between the center of light beam dividing means and the center of a bundle of light beams occurs due to a shift of a condensing optical system at the time of tracking control. A hologram element (2) divides light beams reflected from an information storage medium into at least two positive first order diffracted light beams. The hologram element (2) has a line (D1) extending in a radial direction and passing through an optical axis (OZ) and a division line (D2) having segments at least both ends thereof and a bulge in a center thereof, wherein the segments are substantially parallel to the line (D1), and the bulge (44) bulges toward the periphery of the hologram element (2) so that a top (D5) of the bulge (44) is substantially parallel to the line (D1).

Abstract: This optical disc drive has an optical pickup head that emits a light beam to an optical storage medium, detects the light beam reflected from the optical storage medium, and outputs a signal based on the received reflected light; a jitter measuring unit for measuring jitter in signals output from the optical pickup head; and an evaluation unit for determining from the measured jitter if the optical storage medium is good or defective. The jitter measuring unit measures jitter in a train of 3T or longer marks or spaces from an optical storage medium to which digital information is recorded as a train of marks or spaces of length kT based on a period T and an integer k of two or more.

Abstract: A color reaction detecting device includes: a support configured to support a sensor chip, the sensor chip including a thin film which causes a color reaction by a substance released from an object under inspection; a light source configured to introduce light into the sensor chip supported by the support; a photodetector configured to sense light emitted from the sensor chip; a temperature sensor configured to measure temperature; and a control unit. The control unit computes an amount of color reaction in the sensor chip using a result of the sensing by the photodetector and a result of the measurement by the temperature sensor.

Abstract: A method and apparatus that compensates for power variations occurring in a beam (11) of reflected light from a laser (10) within optical disc recording devices. Signal multiplication techniques are applied to signals indicative of light reflected from the optical disc. The signal multiplication conditions signal indicative of the reflected light by selecting a gain factor from one of a plurality of possible constants. The constant selected by the gain factor is dependent on the determined state of the device. Factors used in determining the gain factor include of the position of the light spot from the laser is currently passing over written track or passing over unwritten tracks, and whether the laser is currently in a read mode or a write mode. These constants as determined create a gain factor corrected signal that is independent of the state of the optical pick-up.

Abstract: A disc having an updatable defect management area used by an apparatus for managing defects on the disc, the disc including a user data area which includes user data, a spare area that is a substitute area for a defect existing in the user data area, and an area in which are recorded an address of data that is last recorded in the user data area and an address of a replacement data recorded in the spare area. Accordingly, the disc defect management method and apparatus are applicable to a recordable disc such as a write-once disc while effectively using a defect management area of the disc.

Abstract: The disk carrying apparatus includes a lifting portion which carries a disk onto a turntable, a chuck which holds the carried disk on the turntable, and a third switch which detects an intermediate position between a holding operation start position where the chuck starts a disk holding operation and a holding operation end position where the chuck finishes the disk holding operation. After completion of an initial disk holding operation, the chuck returns to the intermediate position detected by the third switch and retries the disk holding operation.

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: A recording apparatus recording data on an optical disk includes a management information checking unit that determines whether or not management information on the optical disk for managing the data recorded on the optical disk exists by checking for management information on the optical disk when the optical disk is inserted in the recording apparatus; an area usage checking unit that determines whether or not a usage history of an optical disk area for optimizing recording power exists by checking a use condition of the optical disk area for optimizing recording power; and an abnormality detection unit that determines whether or not an optical disk abnormality exists in accordance with the presence or absence of management information on the optical disk and the presence or absence of a usage history of the optical disk area for optimizing recording power.

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: Provided is an optical disk apparatus which has high read retry ability and high compatibility by performing a proper verify for other apparatuses. The optical disk apparatus includes a playback system capable of arbitrarily changing playback performance, and means which detects and determines a factor causing a read error. Moreover, a read retry is performed by use of playback parameters corresponding to the factor causing the read error. Furthermore, a verify is performed with the playback performance of the playback system lowered.

Abstract: A method for recording data on an optical recording medium includes the step of receiving data to be written and control data. The control data includes status information to indicate whether or not an other sector within a block in which a sector is included is valid. The data is written in an other sector within the block. The method further includes determining whether to perform an error certification process based on the control data, and writing the data based on the result of determining step.

Abstract: The invention relates to recording of information, in particular a real-time audio and/or video signal, in a recording track (3) of a recording medium (2) divided into blocks (45). The recording medium contains a defect list (BS) of addresses of blocks (45*) which are known to be defective. This list is read and during the recording process the defective blocks are skipped. The recording process is performed without any read-after-write check so as to speed up the process. The defect list is updated by noting, during playback, which blocks give rise to reading problems and by including the addresses of these blocks in the defect list on the recording medium.

Abstract: A device for delivering a data signal at a data rate has crosstalk cancellation. The crosstalk reducing unit (14) has an adaptive filter (15) to generate a crosstalk signal corresponding to a track adjacent to a track being scanned. A subtractor (16) subtracts the crosstalk signal from a read signal. A calculating unit (17) calculates filter coefficients for the adaptive filter. The adaptive filter (15) and subtractor (16) are coupled to an asynchronous clock (18) for operating at an asynchronous sample rate. The crosstalk reducing unit (14) has a sample rate converter (19) coupled to a synchronous clock for converting the output of the subtractor to the data signal (8) at a synchronous sample rate. A timing recovery unit (11) is coupled to the data signal (8) for retrieving the synchronous clock corresponding to the data rate.

Abstract: A data assurance method controls an optical head according to the difference between the device temperature and the temperature of inserted removable optical storage media. A rate of temperature change c is calculated from the output of a temperature sensor which detects the device temperature, and then the temperature of the media is estimated. A transition is made to special processing, and a return is made from special processing in a state with a temperature difference to normal processing depending on the rate of temperature change. Consequently a return to normal processing can be made safely and quickly.

Abstract: In the tilt correction method, information about inclination of an object lens relative to an information recording medium is acquired. A direct current signal Sdc for correcting the inclination is produced based on the information. An alternating current signal Sac having a prescribed signal characteristic is superposed onto the direct current signal Sdc to produce a driving signal Sout. The driving signal Sout is supplied to a driving mechanism to correct the inclination of the object lens against friction.

Abstract: Method and apparatus for use in an optical disk tilt servo system of an optical disk drive. The tilt servo system is for adjusting an angle between a surface of an optical disk and a pick-up head of the optical disk drive. The method includes: measuring focusing results of the optical disk at multiple locations and estimating tilt angles, i.e. deviation from the horizontal, of the surface of the optical disk according to a physical model that reflects that the optical disk has different tilt angles at different locations. The tilt servo system is calibrated accordingly.

Abstract: A method of detecting a servo error, an apparatus therefor, a disk which maintains quantity of a servo error signal, a method of controlling a servo of an apparatus for recording data on and reproducing data from a disk, a method of detecting the tracking error, and a method of detecting tilt error of the apparatus.

Abstract: A storage unit with shockproof function and accessing method thereof is provided. The storage unit includes a storage media, a speed sensing device or a vibration sensing device and a control unit. The storage unit is capable of operating in an environment with strong vibration and avoiding most read/write errors at a reduced production cost.

Abstract: An optical disk unit includes the following: a storage part temporarily storing data to be written to an optical disk; a processing part processing the data; an encoder part modulating and outputting the processed data; a writing control part controlling writing of the data to the optical disk; and a writing command part detecting an occurrence of a state of suspension of supply of the data to the storage part and providing an operation command to the writing control part in accordance with the detection result. In the case of suspending the writing of the data to the optical disk, the writing control part causes the processing and encoder parts to stop accessing the storage part by setting the processing and encoder parts in a wait state after the processing and encoder parts access the storage part, and causes the storing of the data in the storage part to be stopped.

Abstract: The present invention provides a device and method for an optical disc such as a DVD which can keep proper edge position of a recording pulse to record data of high quality without depending on a fluctuation in a supply voltage and a fluctuation in a temperature. The optical disc device according to the present invention comprises a laser driver for driving a laser to record data on an optical disc, a recording pulse generator for generating a recording pulse signal by using a predetermined delay circuit, to control the switching of the laser power of the laser driver, a delay amount measuring section for measuring the delay amount of a delay circuit in the recording pulse generator, and a recording pulse position correction section for correcting the predetermined edge position of the recording pulse based on the result of the measurement.

Abstract: Provided are a method and apparatus for removing vibration due to the imbalance of weight of a disc in a disc drive, in which the allowable high multi-speed of a disc is determined based on the allowable amount of vibration in the disc drive and the disc drive is actuated within a range of the allowable high multi-speed. The method includes detecting the amount of vibration corresponding to the degree of imbalance of the weight of a disc inserted into the disc drive and increasing a set high multi-speed of the disc drive until the amount of vibration reaches an allowable amount of vibration with respect to the disc drive. Accordingly, vibration in a disc drive can be controlled such that a user cannot perceive it and damages to the disc drive due to the vibration can be minimized.

Abstract: When an error requiring a retry operation occurs, information concerning the error is stored every time. The information includes a sector number (or beginning sector number and number of sectors), the content of the command; a write or read designation, and the number of the times of error occurrence in the sector (or number of the times of retry operation), for example. In the case of recording information, like the prior art, information to be written which is stored in a buffer memory is held as is. Since the information concerning an error requiring a retry operation is stored, even though that error occurs repeatedly, a write and/or read operation of the next executable command to another track is executed without immediately switching to the retry operation. Thus, other commands are executed between the occurrence of the error requiring a retry operation and actual execution of the retry operation.

Abstract: A plurality of tracks on an optical disk are optically read to obtain a signal containing a plurality of LOW segments. Each of the plurality of LOW segments should correspond to a certification pit. Accordingly, if the interval between LOW segment Xj and nth succeeding LOW segment Xj+n exceeds the length of one track, a defect pit that could be confused with a certification pit is judged as being present between two certification pits.

Abstract: An optical media drive contains light reflective surfaces positioned about a transparent center portion of the optical media. The light reflective surfaces reflect laser light from a laser unit of the drive which is directed toward the transparent center portions of the optical media. Defects such as cracks in the optical media disturb the reflection. The disturbance is detected by a laser lens and represented by a signal corresponding to the size of the defect. Information about the cracks is used to determine a safe spin rate for the optical media.

Abstract: The present invention provides a method for adjusting the mechanical error of an optical disc reading device. The optical disc reading device consists of a driving device and an optical pickup. The driving device has a base plate for supporting and rotating an optical disc. The method consists of moving the optical pickup to surface of optical disc, the optical pickup emitting two tracking light spots onto the surface, and the optical pickup reciprocally moving relative to the surface. Next, the optical pickup reads reflected signal of two tracking light spots for generating a track crossing signal. By using the track crossing signal, the method adjusts position of optical pickup relative to the base plate.