Abstract: An optical disc device includes: an optical pickup including a first laser light source that emits laser light, an objective lens that focuses the laser light emitted from the first laser light source onto an optical disc, and a light receiving element that receives reflected light from the optical disc, and performs photoelectric conversion on the reflected light received to output a received-light signal; an FS signal generator that generates an FS signal indicating the light amount of the reflected light from the optical disc, based on the received-light signal from the light receiving element; and a dirt determiner that determines that dirt is present in the optical pickup, when the peak level of the FS signal is less than a dirt determination threshold, and controls the light receiving element to increase the peak level of the received-light signal from the light receiving element.

Abstract: An optical disc device is configured to reproduce an optical disc. The optical disc device includes an optical pickup, a high-frequency production component, a driver and a controller. The optical pickup includes a laser emission component configured to emit a laser beam, and a light receiver configured to receive returning light of the laser beam. The high-frequency production component is configured to produce a high-frequency signal. The driver is configured to produces a drive signal for driving the laser emission component by superposing the high-frequency signal produced by the high-frequency production component onto a specific drive signal. The controller is configured to control the high-frequency production component to adjust an amplitude of the high-frequency signal.

Abstract: An optical disc device that reads information recorded in an optical disc medium includes an objective lens that focuses light on the optical disc medium, a spherical aberration correction mechanism that changes an amount of spherical aberration of the objective lens according to a setting value of a predetermined parameter, and an evaluation value measurement section that measures an evaluation value indicating the accuracy of reading of information from the optical disc medium. The optical disc device further includes a control section that executes adjustment processing in which the control section carries out plural times of measurement of the evaluation value by the evaluation value measurement section concurrently with changing the amount of spherical aberration of the objective lens by the spherical aberration correction mechanism and calculates an optimum setting value of the parameter based on plural evaluation values obtained by the plural times of measurement.

Abstract: Disclosed herein is an optical disc apparatus including: an optical pickup radiating light having a first wavelength provided for an optical disc medium of a first type and light having a second wavelength which is smaller than the first wavelength and provided for another optical disc medium of a second type; a signal outputting section outputting a signal according to light reflected by the optical disc medium to reflect light radiated by the optical pickup; and a type determination section requesting the optical pickup to radiate light having the first wavelength to an object optical disc medium to acquire the signal output by the signal outputting section and determining the type of the object optical disc medium in accordance with the number of peaks appearing in the acquired output signal output by the signal outputting section while moving the optical pickup in a direction to the object optical disc medium.

Abstract: Disclosed herein is an optical disc apparatus capable of reading out information stored in an optical disc medium, the optical disc apparatus including: a light emitting device radiating light; an object lens converging light radiated by the light emitting device on the optical disc medium; and a control section carrying out control to shift the center position of the object lens with respect to the optical-axis position of light radiated by the light emitting device in an operation to read out information from the optical disc medium.

Abstract: An optical recording device that records to a multi-layer disk having multiple recording layers includes a controller which sets a data area in which user data is recorded, and a calibration area including a main calibration area and at least one sub-calibration area which are used to calibrate the intensity of laser light for recording, with the same layout among the plurality of recording layers, conducts first calibration for performing initial recording in the data area by using the main calibration area, records dummy data in the remainder of the main calibration area, and conducts second calibration for performing additional recording in the data area by using the sub-calibration area.

Abstract: A multi-layer recording medium is constituted by guide layer-equipped optical disks having a plurality of recording layers and guide layers are integrated by bonding said disks to one another so as to produce a double-sided disk, both sides of which may be used for recording. With regards to the lead-in areas for the guide layers of the guide layer-equipped optical disks for both sides, single-sided disks and double-sided disks are identified, and face-management information for identifying the side surfaces in the case of a double-sided disk is recorded in advance in said lead-in areas using wobbles or the like. As a result, the likelihood of the occurrence of defective products caused by the inability to read the face information can be reduced.

Abstract: A system and method for adjusting the radial tilt, tangential tilt, or a combination of radial and tangential tilt of an optical detection unit in an optical disc reading system can include applying different weighting factors to different signal components depending on which detection area detects the component, measuring a value of a signal characteristic, such as signal-to-noise ratio, of two signals with different sets of weighting factors, and determining an adjustment factor to the radial tilt as a function of the of the measured signal characteristic values.

Abstract: A tracking control method relates to an optical pickup 11 including an object lens 11a for focusing laser light on an information recording surface of an optical disc 40, and a light receiving element 11b that receives reflected light from the information recording surface of the optical disc 40 and converts the light to an electric signal. The tracking control method includes a lens middle point control step (S4) of controlling a position of the object lens 11a so as to suppress vibration of the object lens 11a based on a signal obtained by feedback of a lens error signal generated from the electric signal, a tracking pull-in step (S9) of performing tracking pull-in processing to control a position of the object lens 11a to follow a track of the optical disc 40, and a step (S7) of lowering a loop gain of the feedback of a lens middle point control in the lens middle point control step before the tracking pull-in step is started.

Abstract: A device and associated method of use can have at least an object with a work surface that contacts a lapping surface of a tool. Topography of the lapping surface can be mapped in-situ by an adjacent sensor array and the topography stored in a memory. The sensor array may be configured with a plurality of sensors positioned on opposite sides of the object.

Abstract: An optical pickup is configured such that light split by a light-splitting element is received by light-receiving elements provided on a light-receiving surface of a light-receiving unit, has on the light-receiving surface of the light-receiving unit quartered light-receiving portions that detect position-adjustment light and configured by equal quartering so as to be arranged in two dimensions, and in which the position of the light-splitting element is adjusted based on the position-adjustment light received by each of the quartered light-receiving portions.

Abstract: According to one embodiment, a magnetic disk apparatus includes a magnetic disk, a slider including a head element, a heater which heats the slider and vary a protrusion amount of the head element toward the magnetic disk, a controller which performs DFH control to vary a control amount for power applied to the heater at a fixed period of time, a sensor which outputs a signal corresponding to the protrusion amount of the head element, and a determination unit which determines a touchdown of contact between the magnetic disk and part of the slider, based on a peak value of a DC output signal of the sensor.

Abstract: Provided are an optical information recording/reproduction device and an optical information recording/reproduction method with which retry data during verify error detection can be efficiently recorded. In the optical information recording/reproduction device for recording data on an optical information recording media and reproducing data from an optical information recording medium, if verify error data is detected at a first cure unit region on the optical information recording medium, verify error retry data is recorded at a second cure unit region which is different to the first cure unit region.

Abstract: The present invention relates to an optical information processing apparatus and to a method for controlling same. Provided is an optical information processing apparatus and a method for controlling same, the optical information processing apparatus comprising: a light source for irradiating light; an optical modulator for modulating the light irradiated from the light source; an optical system for collecting the light modulated by the optical modulator and enabling the modulated light to be incident to an optical medium; a stage on which the optical medium is placed; an optical detection unit for detecting the pattern of the light reflected from the optical medium; and a control unit for analyzing the pattern of the light detected by the optical detection unit so as to control the optical system and the location of the stage.

Abstract: An optical information processing apparatus includes: a unit that radiates light onto an optical disc and detects the reflected light to output a reproduced signal; a unit that corrects spherical aberration of the light; a unit that adjusts a focus position of the light based on a focus adjustment value; and an adjustment unit that measures a characteristic of the reproduced signal at each of at least three positions on each of at least three straight lines on a plane with coordinate axes representing an amount of spherical aberration correction and focus adjustment value, obtains, from the measurements, as estimated positions, at least five positions on the plane at which the characteristic has substantially the same value, performs an ellipse approximation on the estimated positions, obtains a center of the ellipse, and determines the amount of spherical aberration correction and focus adjustment value based on the center of the ellipse.

Abstract: A photodetector outputs a first signal and a second signal corresponding to light amounts of the received first light flux and the received second light flux, first and second low band extraction circuits extract low band components of the first signal and the second signal, first and second high band extraction circuits extract high band components of the first signal and the second signal, a differential circuit calculates a difference signal between a high band component difference signal as a difference between the high band component of the first signal and the high band component of the second signal and a low band component difference signal as a difference between the low band component of the first signal and the low band component of the second signal, and a control signal processing section generates a tilt control signal based on the calculated difference signal.

Abstract: An optical disk device including: an optical pickup which includes a collimator and an object lens for focusing parallel light beams from the collimator at a position on an optical disc; a collimator driver unit which moves the collimator in an optical axis direction; a movement mechanism driver unit which moves the optical pickup in the radial direction; and a drive control unit which performs an adjustment process for adjusting the positions of the object lens and the collimator. In the adjustment process, the drive control unit causes the collimator driver unit to operate after stopping the movement mechanism driver unit or a spindle motor, and causes the movement mechanism driver unit or the spindle motor to re-start operating after the collimator driver unit finishes moving the collimator.

Abstract: A control mechanism may control the height and/or position of a read/write head configured to interact with a rotating information storage surface. A computation unit may compute a detected topography from gap measurements using a dynamic filter including a model of read/write head dynamics. A sensor may detect gap measurements of a side read/write track while the read/write head is interacting with a current read/write track. A memory may store the detected topography. The control mechanism may adjust the height of the read/write head based on the detected and/or stored topography. The control mechanism may be a reactionless control mechanism configured to apply a counterforce to offset movements of the read/write head and/or a slider.

Abstract: A control mechanism may control the height and/or position of a read/write head configured to interact with a rotating information storage surface. A computation unit may compute a detected topography from gap measurements using a dynamic filter including a model of read/write head dynamics. A sensor may detect gap measurements of a side read/write track while the read/write head is interacting with a current read/write track. A memory may store the detected topography. The control mechanism may adjust the height of the read/write head based on the detected and/or stored topography. The control mechanism may be a reactionless control mechanism configured to apply a counterforce to offset movements of the read/write head and/or a slider.

Abstract: Some of the embodiments of the present disclosure provide a method for operating a disc drive system, the method comprising based at least in part on a first injector signal, oscillating a focusing apparatus of the disc drive system; while oscillating the focusing apparatus of the disc drive system and rotating a disc placed within the disc drive system, estimating an amplitude of a track crossing speed signal; generating a second injector signal having a frequency that is substantially the same as a frequency of the first injector signal; and based at least in part on the estimated amplitude of the track crossing speed signal and the second injector signal, estimating a sign of the track crossing speed signal.

Abstract: A control mechanism may control the height and/or position of a read/write head configured to interact with a rotating information storage surface. The control mechanism may be a reactionless control mechanism configured to apply a counterforce to offset movements of the read/write head and/or a slider. A topography detection mechanism may detect topography of a side read/write track while the read/write head is interacting with a current read/write track. A memory may store the detected topography. The control mechanism may adjust the height of the read/write head based on the stored topography. The topography detection mechanism may compute the detected topography from gap measurements using a dynamic filter including a model of read/write head dynamics.

Abstract: An optical-information reproducing apparatus for reproducing information from an optical-information storage medium where an interference pattern between a signal beam and a reference beam is recorded as page data by being angle-multiplexed, the optical-information reproducing apparatus, including a light-source for emitting a light beam, an optical element for splitting the light beam into the reference beam and the signal beam, an angle-controlling element for controlling the reference beam into a direction which is perpendicular to the angle-multiplexed direction, the reference beam being guided to enter the optical-information storage medium, an optical detector for detecting a reproduced image which is reproduced by the reference beam, and a position-controlling circuit for controlling position relationship between the reference beam and the optical-information storage medium.

Abstract: An optical information recording/reproduction device includes a detection unit which detects a focus-direction height of a recording medium, a focus adjustment unit which adjusts a focus-direction distance between the recording medium and a signal light optical system and a reference light system, and a control unit which controls the focus adjustment unit so that a relative distance between the object lens of the signal light optical system and the recording medium is adjusted according to the focus-direction height of the recording medium detected by the detection unit.

Abstract: An optical information recording medium includes a recording layer in which a track is formed, the track having recording marks linearly arranged thereon. Each recording mark has a dimension corresponding to a reference mark length, which serves as a reference, in a track direction along which the track extends, the dimension being smaller than dimensions of the recording mark in two directions perpendicular to the track direction.

Abstract: A system and method for adjusting the radial tilt, tangential tilt, or a combination of radial and tangential tilt of an optical detection unit in an optical disc reading system can include applying different weighting factors to different signal components depending on which detection area detects the component, measuring a value of a signal characteristic, such as signal-to-noise ratio, of two signals with different sets of weighting factors, and determining an adjustment factor to the radial tilt as a function of the of the measured signal characteristic values.

Abstract: There is proposed an optical disk recording method that can prevent degradation of recording quality due to occurrence of thermal interference, and an optical disk recording reproduction device used in this recording method.

Abstract: An optical-information reproducing apparatus for reproducing information from an optical-information storage medium where an interference pattern between a signal beam and a reference beam is recorded as page data by being angle-multiplexed, the optical-information reproducing apparatus, including a light-source for emitting a light beam, an optical element for splitting the light beam into the reference beam and the signal beam, an angle-controlling element for controlling the reference beam into a direction which is perpendicular to the angle-multiplexed direction, the reference beam being guided to enter the optical-information storage medium, an optical detector for detecting a reproduced image which is reproduced by the reference beam, and a position-controlling circuit for controlling position relationship between the reference beam and the optical-information storage medium.

Abstract: An optical recording/reproducing device which minimizes the number of home-in operations to move a pickup to a predetermined reference position of a disc, and a method of controlling the same. The optical recording/reproducing device includes a pickup to record or reproduce information on or from a disc, a pickup movement motor to move the pickup along the disc, a main power supply controller to detect whether power is initially supplied so as to output a home-in control signal, and a drive controller to perform a home-in operation, only when power is initially supplied according to the home-in control signal of the main power supply controller. Since the home-in operation is performed only when power is initially supplied, the number of home-in operations is minimized.

Abstract: A disc inspecting method includes: forming recording marks on a disc; scanning the recording marks from inside to outside or from outside to inside of the disc by a pickup unit to read a reproduction signal while rotating a spindle to move a slider by each predetermined width; acquiring reproduction data from the reproduction signal in a signal acquiring unit; and determining whether or not the reproduction data is proper in a calculation unit, and optimizing a formation condition of the recording marks when it is determined that the reproduction data is not proper.

Abstract: An optical pickup device corresponding to an optical recording medium having a plurality of recording layers, and an optical drive using the device are provided. The optical pickup device includes a collimator lens disposed between an object lens and a light source. The collimator lens adjusts a focal length with respect to the optical recording medium, and the object lens focuses light passing through the collimator lens, on the optical recording medium. The object lens is optically optimized for an upper or second-upper recording layer of the optical recording medium.

Abstract: A method for calibrating a tilt of an actuator includes the following steps: focusing a light beam projected from an objective lens onto a data layer of an optical disc; utilizing a digital signal processor to output control voltages through an analog driving circuit for driving the actuator to tilt the objective lens, and accordingly recording corresponding displacement signals of the objective lens; fitting a tilt curve through the recorded control voltages and the displacement signals; utilizing the digital signal processor to output a zero control voltage, not through the analog driving circuit, for tilting the objective lens, and accordingly measuring a standard displacement signal; acquiring a bias voltage from the tilt curve according to the standard displacement signal; and calibrating the tilt of the actuator by offsetting a control voltage outputted from the digital signal processor according to the bias voltage for controlling the analog driving circuit.

Abstract: Method and apparatus for writing repeating patterns of features to a substrate, such as a data storage medium. In accordance with some embodiments, a multi-dimensional pattern of discrete features of different sizes to be written to a substrate is divided into a plurality of contiguous regions. A unique set of compensation values is assigned to each region. A write beam of a write system is used to write the features to the substrate responsive to said unique sets of compensation values so that all of the features having a common size in at least one region are written using the same compensation values from the associated set.

Abstract: An electron beam writing method for writing a fine pattern that includes servo patterns and groove patterns, the method including the step of adjusting an exposure amount of the resist by changing, when controlling application timing of the electron beam by an ON/OFF signal to a blanking unit that blocks the electron beam, an application duty ratio of the electron beam by the ON/OFF signal with respect to each writing radius position for each pattern based on sensitivity variation data of the resist with respect to post exposure delay for each pattern.

Abstract: In optical recording and/or reproduction using an SIL optical system that performs a tilt servo using light for recording and/or reproduction, the SIL and an optical recording medium have a high probability of colliding with each other before the tilt servo is started. To prevent the collision, an optical recording/reproduction method performs a gap servo that controls a gap between a surface of an optical recording medium and a bottom surface of an SIL using reflected light that is generated from light traveling from the bottom surface of the SIL and reflecting on the optical recording medium, a focus servo that controls a distance between a focal point of the light and the bottom surface of the SIL, and a tilt servo that controls a tilt of the bottom surface of the SIL relative to the surface of the optical recording medium using the reflected light.

Abstract: Aspects of the disclosure provide a method for mounting a storage disc. The method includes receiving data stored at a location on the storage disc. The location on the storage disc used for providing a structure of the storage disc as a result of a previous recording on the storage disc. Then, the method includes determining a medium type based on a parameter in the structure that is indicative of the medium type.

Abstract: A system and method for adjusting the radial tilt, tangential tilt, or a combination of radial and tangential tilt of an optical detection unit in an optical disc reading system can include applying different weighting factors to different signal components depending on which detection area detects the component, measuring a value of a signal characteristic, such as signal-to-noise ratio, of two signals with different sets of weighting factors, and determining an adjustment factor to the radial tilt as a function of the of the measured signal characteristic values.

Abstract: An optical information recording medium includes a recording layer in which a track is formed, the track having recording marks linearly arranged thereon. Each recording mark has a dimension corresponding to a reference mark length, which serves as a reference, in a track direction along which the track extends, the dimension being smaller than dimensions of the recording mark in two directions perpendicular to the track direction.

Abstract: Focus control is performed for an optical disc having at least two data layers. One data layer is located closer than the other to a beam-incident surface of the disc. Maximum levels in positive and negative sides on a characteristic curve of a focus error signal obtained from the disc are obtained for both data layers. First and second focus balance values are obtained based on the maximum levels for the data layers, respectively. It is determined whether a difference between the first and second focus balance values satisfies at least either a first requirement or a second requirement. The first requirement requires that the difference exceed a predetermined threshold value. The second requirement requires that the second focus balance value be smaller than a predetermined threshold value. A focus balance value is selected depending on a result of the determination, for focus control.

Abstract: A super resolution medium (1) is provided with an information signal region (11) where a content, such as a video or audio content, is recorded and a test read region (12) where reproduction setting value adjustment information is recorded for adjusting a setting value for reproduction. A shortest mark length on a first prepit row formed in the information signal region (11) is shorter than a length of an optical system resolution limit of a playback apparatus. The types of mark lengths, recorded in the test read region (12), on the second prepit row for adjusting the setting value are the same as part or all types of mark lengths on the first prepit row. Further, the second prepit row includes a prepit having a mark length shorter than the length of the optical system resolution limit of the payback apparatus. Still further, each of the first and second prepit rows has at least three types of mark lengths.

Abstract: A disc-shaped information recording medium includes a laminate of recording layers on and from which an information signal can be optically recorded and reproduced from one side of the medium. Data areas are provided in the recording layers, respectively. The information signal can be recorded on and reproduced from the data areas while a laser beam emitted from an optical pickup is applied to the data areas. Optical recording test areas are provided in the recording layers, respectively. A test signal can be recorded on and reproduced from the optical recording test areas to decide optimum power values of the laser beam for signal recording. The test areas are out of overlap as viewed in a direction of propagation of the laser beam.

Abstract: An optical disc drive apparatus (100) of the present invention rotates an optical disc (1) at a predetermined rotation speed using a motor (2). An optical pickup (3) irradiates the optical disc (1) with a laser beam (5) emitted from an internal semiconductor laser (4) included therein, and obtains a reproduction signal (7) based on a laser beam reflected from the optical disc (1). A laser driving unit (8) controls a driving current (9) of the semiconductor laser (4) to a predetermined level, and superimposes a high-frequency current (11) having a predetermined level on the driving current (9). In a high-speed reproduction mode, a control unit (12) sets the rotation speed of the optical disc (1) higher, the power of the laser beam (5) irradiating the optical disc (1) higher, and the level of the high-frequency current (11) lower than in a normal reproduction mode.

Abstract: A network-based real-time optic disc writer device has at least two disc writer assemblies and a monitoring unit. Each of the disc writer assemblies has a disc writer unit and host controller with a detection unit. The disc writer unit is electrically connected to the host controller and has a robotic arm, at least two disc writers, and an optic disc deposition zone. The at least two disc writers and the optic disc deposition zone are arranged at one side of the robotic arm to allow the robotic arm to selectively pick up and deposit optic discs and also to allow the at least two disc writers to perform continuous writing to optic discs. The monitoring unit communicates with the host controller of each of the disc writer assemblies, so as to enable ready communication through networks, real-time notification and monitoring and continuous, un-interrupted writing operation of optic discs.

Abstract: An optical pickup device, an optical disk drive and method of controlling light performed by the optical pickup device are provided. The optical pickup device includes: a light transmitting system including an object lens for facing a medium having a multi recording layer for storing information, a light source system for providing a plurality of beams used to record information on or reproduce information from the multi recording layer via the light transmitting system, a light-receiving system disposed on a path of a beam reflected from the medium, and a light controller including a light control device for controlling stray light generated in the medium such that the stray light does not reach the light-receiving device.

Abstract: According to one embodiment, an information reproduction apparatus includes an information acquisition unit, an error detection unit, and a control unit. The information acquisition unit is configured to irradiate a reference beam, convert the reference beam into a luminance signal, and output the luminance signal when reproducing an information recording Medium. The error detection unit is configured to detect at least one selected from a first error and a second error by extracting a feature extraction quantity from the luminance signal. The first error is of an irradiation angle of the reference beam. The second error is of at least one selected from a temperature and a wavelength of the reference beam. The control unit is configured to control at least one selected from the irradiation angle and the at least one selected from the reproduction temperature and the wavelength of the reference beam using the second error.

Abstract: There is provided a control device including a recording portion that records data on a disk by shining a laser beam onto a recording surface of the disk, a reading portion that reads the data on the disk, a control parameter computation portion that computes a control parameter, a differential computation portion that computes a differential between the control parameter and a value that is set in advance for the disk, a determination portion that determines whether the differential that the differential computation portion has computed is within a range of a dead band, an output value computation portion that computes an output value for the laser beam, an output control portion that controls the laser beam, a storage portion that stores a plurality of combinations of the dead band and the gain, and a selecting portion that selects one of the combinations of the dead band and the gain.

Abstract: A multilayer optical disc which has three or more recording layers and enables easy positioning of a focused beam spot onto a particular recording layer in which a BCA is disposed. An inter-layer distance between a particular recording layer and a recording layer adjacent to the particular recording layer is larger than the other inter-layer distances in which, at the focused beam spot positioning, the focused beam spot traverses the said adjacent recording layer earlier than the other recording layer adjacent to the particular recording layer.

Abstract: A method for inspecting an optical information storage medium includes the steps of: irradiating the storage medium with a laser beam and rotating the medium by a constant linear velocity control technique by reference to the radial location at which the laser beam forms a spot on the medium; changing the rotational velocities according to the radial location on the medium between at least two linear velocities that include a first linear velocity Lv1 and a second linear velocity Lv2 higher than the first linear velocity Lv1; generating a focus error signal and/or a tracking error signal based on the light reflected from the medium; performing a focus control and/or a tracking control on the laser beam that irradiates the medium based on the focus and/or tracking error signal(s); and passing the branched outputs of control loops for the focus and/or tracking error signal(s) through predetermined types of frequency band-elimination filters for the focus and/or tracking error signal(s) to obtain residual errors

Abstract: In an optical information reproduction method for reproducing information using holography from a medium which records an interference pattern generated when overlapping a signal beam and a reference beam, the reference beam is radiated to the medium at a reference beam angle with a predetermined range for reproducing the information, a reproduction beam is generated by diffracting the reference beam with the interference pattern, the reproduction beam is detected by a photodetector; and the information is reproduced by processing a signal detected by the photodetector.

Abstract: To provide an optical disc device 1, and similar, equipped with a new mechanism to reduce laser light noise due to optical feedback. In an optical disc device 1 in which a laser diode is driven by a high frequency modulation method, optical feedback is returned to the laser diode at a timing at which the phase of the injected carrier density is within one of the following ranges: (1) equal to or greater than the peak phase of the injected carrier density of the laser diode, and equal to or less than the peak phase of the injected carrier density of the laser diode plus 3?/8 (radians); or (2) equal to or greater than the peak phase of the injected carrier density of the laser diode plus 9?/8 (radians), and equal to or less than the peak phase of the injected carrier density of the laser diode plus 2? (radians).

Abstract: A method and apparatus for detecting a touch-down and contact between a head and a storage medium by using a signal generated by a data storage device, specifically by a sensor installed in a slider. The method includes: separating a signal detected by a sensor into a direct current (DC) component and an alternating current (AC) component, wherein the sensor has an electrical characteristic that changes according to temperature; using the DC component to detect a touch-down state of the head during a touch-down test to determine a value of a control signal for adjusting the flying height of the head; and using the AC component to detect a contacting state between the head and the storage medium in an operating state of the apparatus.