Abstract: There is described a method for compensation of gain variations in a multistage optical amplifier, for the amplification of an optical wavelength multiplex signal, comprising several amplifier stages in series, each with at least one pumping device. Gain variation occurring after a switching process can easily be compensated for, when the power jump expected at the second amplifier stage is determined and, depending thereon, a new pump power is calculated for the corresponding pump device, the new pump power is set for the pump device before the power jump arrives at the input of the second stage.

Abstract: A day/night weapon sight assembly that consists of daytime sight and a nighttime sight allows the use of both sights without change in eye relief even when the nighttime sight is attached to the rear end of the daytime sight. This is achieved by supporting the daytime sight moveably in the direction of the optical axis and by supporting the nighttime sight with the use of a plane-parallel motion mechanism that allows switching of the nighttime sight between the upper inoperative position and the operative position behind and coaxially with the daytime sight.

Abstract: A catadioptric projection objective for projecting a pattern arranged in the object plane of the projection objective into the image plane of the projection objective, having: a first objective part for projecting an object field lying in the object plane into a first real intermediate image; a second objective part for generating a second real intermediate image with the radiation coming from the first objective part; a third objective part for generating a third real intermediate image with the radiation coming from the second objective part; and a fourth objective part for projecting the third real intermediate image into the image plane.

Abstract: A reduction projection objective for projection lithography has a plurality of optical elements configured to image an effective object field arranged in an object surface of the projection objective into an effective image field arranged in an image surface of the projection objective at a reducing magnification ratio |?|<1. The optical elements form a dry objective adapted with regard to aberrations to a gaseous medium with refractive index n?<1.01 filling an image space of finite thickness between an exit surface of the projection objective and the image surface. The optical elements include a largest lens having a maximum lens diameter Dmax and are configured to provide an image-side numerical aperture NA<1 in an effective image field having a maximum image field height Y?. With COMP=Dmax/(Y?·(NA/n?)2) the condition COMP<15.8 holds.

Abstract: A stereomicroscope includes a microscope main body and a camera for assistant. The microscope main body includes therein an objective optical system, a zoom optical system and an eyepiece optical system. The camera for assistant is detachably mounted to the microscope main body. The microscope main body provides to a main operator a pair of optical images including a certain binocular disparity as viewed from an observation direction of the main operator. The camera for assistant provides to an assistant a pair of electron images including a certain binocular disparity as viewed from an observation direction of the assistant. The observation directions of the main operator and the assistant cross at a certain angle. The camera for assistant outputs the pair of electron images into a stereo viewer which is separated from the microscope main body.

Abstract: According to a first embodiment the invention provides for increasing the throughput and reducing the striping due to imperfections in the microlens and/or confocal aperture arrays of a Laser Confocal Scanning Microscope by increasing the number of repeat patterns in the microlens and confocal aperture arrays to more than one, and incorporating an intensity modulation function that ensures constant integrated image intensities at the image detector independent of the instantaneous speed of scanning. According to a second embodiment the invention provides for reducing the striping in a Laser Confocal Scanning Microscope by introducing a second galvanometer mirror such that the emitted laser light beam is descanned at the image (sample) plane.

Abstract: A correct image reflecting telescope with zoom capability comprised of a flat mirror, a parabolic primary mirror, and an image correcting system. The flat mirror reflects the incoming light from the telescope aperture into the parabolic primary mirror. The reflected light from the primary mirror passes back through a small centrally located opening in the flat aperture mirror and into an image correcting lens system. The image correcting system repositions the focal point of the primary mirror from a point in front of the flat aperture mirror to a point behind this mirror for observation with and eyepiece. The image correcting system makes the telescope useful in terrestrial as well as celestial applications and it can be moved with respect to the primary mirror such that a zoom feature results.

Abstract: A first toroidal ray guide defines an axis of revolution and has a toroidal entrance pupil adapted to image light incident on the entrance pupil at an angle to the axis of revolution between 40 and 140 degrees, and it also has a first imaging surface opposite the entrance pupil. A second toroidal ray guide also defines the same axis of revolution and has a second imaging surface adjacent to the first imaging surface. Various additions and further qualities of the ray guides, which form optical channels, are disclosed. In a method light emanating from a source at between 40-140 degrees from an optical axis is received at an entrance pupil of a ray guide arrangement that is circularly symmetric about the optical axis. Then the received light is redirected through the ray guide arrangement to an exit pupil in an average direction substantially parallel to the optical axis.

Abstract: A screen includes a screen main body that has a diffusion layer, a frame that is provided along the circumference of the screen main body, and to which the diffusion layer is attached through supporting members to rock, and a driving unit that is mounted on the diffusion layer and moves the diffusion layer in parallel to a surface of the diffusion layer.

Abstract: An optical multilayer film and reflective screen are provided. An optical multilayer film includes an optical laminate A including a plurality of types of optical layers having different refractive indices laminated on each other, the optical laminate A having a reflection characteristic in which the reflectance peak intensities in the red, green, and blue wavelength regions are substantially the same; and an optical laminate B including a plurality of types of optical layers having different refractive indices laminated on each other, the optical laminate B having a reflection characteristic in which the bottom of the reflectance curve lies in the green wavelength region.

Abstract: An image display apparatus includes a light source; a light modulation element modulating illumination light, coming from the light source on the basis of image data; an illumination area modification unit capable of reducing an illumination area for the light modulation element in order to illuminate a specific image-forming area in the image-forming area of the light modulation element; and an image display-processing unit having an illumination area control unit for controlling the illumination area modification unit and a resolution conversion unit for converting a resolution of the image data into a resolution corresponding to the specific image-forming area.

Abstract: A high resolution 2D/3D switchable display apparatus includes a display panel having display elements arranged in pixel units and configured to display an image. A lenticular lens array includes a plurality of lenticular lenses arranged in a horizontal direction and dividing light corresponding to a signal emitted from the display panel to visual regions of left and right eyes. A spatial optical modulator includes a plurality of cells configured to switch on or off in synchronization with a vertical scanning time of the display panel, wherein each of the plurality of cells is changed to a transparent or opaque state. The display panel sequentially displays an even field including even sequence data of a left eye image and a right eye image and an odd field including odd sequence data of the left eye image and the right eye image.

Abstract: In a display panel, a plurality of pixel sections are arranged in the form of a matrix. Each of the pixel sections includes a pixel for displaying an image for the left eye and a pixel for displaying an image for the right eye. Lenticular lens having repeated convex surfaces is disposed in front of the display panel to deflect the light emitted from each pixel in the horizontal direction from the pixel for displaying the image for the left eye to the pixel for displaying the image for the right eye in each pixel section. Reflection plate reflects the exterior light toward the display panel and has surface projections on the surface. In this case, the focal distance f of the lens is different from the distance H between the surface of the reflection plate and the apex of the lens.

Abstract: In a method of manufacturing a reflective type polarizing diffusive film, a shielding reflection layer is formed on one surface of a substrate, a plurality of grooves are then formed on the shielding reflection layer, and finally, a diffusive layer is formed on the shielding reflection layer. Each of the grooves penetrates into the substrate for light to pass therethrough. Due to the grooves on the shielding reflection layer and the electromagnetic wave, light vibrating in a direction normal to an axis of the shielding reflection layer is blocked by a reverse electric field induced by the shielding reflection layer, and light vibrating in a direction parallel to the axis of the shielding reflection layer is allowed to pass through the shielding reflection layer to produce polarized light. The blocked light is reflected by the shielding reflection layer to the original optical path for reuse, so as to provide largely enhanced brightness.

Abstract: An optical disc apparatus is disclosed that comprises a jitter value detecting circuit that detects a jitter value based on the signal read out from an optical disc; and a defocus value setting circuit that adjusts a defocus value used for moving an objective lens along the direction of a light axis when focusing of the objective lens to the optical disc is performed, based on the signal that has gone through the jitter value detecting circuit, and causes a defocus adjustment to be made based on the defocus value.

Abstract: An optical member utilizing diffraction, which comprises a substrate having a fine structure comprising microstructures with an interval of 50-1,000 nm between the adjacent microstructures on a substrate surface, wherein the substrate has a surface layer portion comprising a region containing fluorine atoms in an amount larger than that in the inner layer portion thereof. The microstructures are preferably micro-protrusions each tapering toward the tip in the direction perpendicular to the substrate surface. The optical member is manufactured by a method comprising a step of exposing the surface of the substrate having a fine structure comprising microstructures with an interval of 50-1,000 nm between the adjacent microstructures to an atmosphere containing a fluorine gas.

Abstract: An image pickup apparatus which is capable of suppressing generation of shadows even when the aperture of the photographic lens is stopped down. A digital camera as an image pickup apparatus includes a photographic lens, a image pickup element that picks up an image of an object, and an optical low-pass filter disposed between the photographic lens and the image pickup element. The filter includes a liner phase diffraction grating having unit cells which are disposed in a regular pattern at a grating pitch P and are formed by equal-width recesses and equal-width protrusions adjacent to each other. When a shortest wavelength of a reference wavelength employed is ?S, and a longest wavelength of the reference wavelength is ?L, an optical path difference ?H between lengths of optical paths of light of which a phase is varied by the phase grating is larger than ?S/2 and smaller than ?L/2.

Abstract: The invention provides a diffractive optical element that can be used as a light beam splitter device, an optical low-pass filter or the like having a two-dimensionally multi-valued fine periodic structure. The surface of a transparent substrate for the diffractive optical element is divided into fine rectangular areas of identical shape which line up in two orthogonal directions while a plurality of rows line up with ends in alignment in any one of the directions. With respect to standard wavelength light incident vertically on the surface of the transparent substrate, an l-th, and a (l+1)-th rectangular area in an l-th row, where l is an odd number, gives a phase 2p?, and a phase {(4q+1)?/2+??/2}, respectively, and an l-th, and a (l+1)-th rectangular area in a (l+1)-th row gives a phase {(4r+3)?/2+3??/2}, and a phase {(4s+2)?/2+??}, respectively. However, ?0.25???0.25, and p, q, r, and s is an integer.

Abstract: Composite mirror systems include a wideband thin film interference stack having a plurality of microlayers and an optically thick layer having a refractive index greater than air but less than the smallest refractive index of the stack. The mirror systems can provide high reflectivity for light propagating in the stack and in the optically thick layer at supercritical angles, while avoiding degradation in reflectivity if dirt or other disturbances such as absorbing materials are present at the mirror backside for example due to contact with a support structure.

Abstract: Optical filters are provided that include a coating layer formed of multiple thin film materials deposited on a visually transparent substrate, wherein the optical filters meet or exceed the physical properties and/or the spectral performance properties of comparable long-pass colored glasses regardless of the transmittance transition point of the colored glasses.

Abstract: An optical filter is provided which includes a plurality of hard coating layers of alternating high and low refractive index provided on a substrate and has an associated first transmission band. The filter also includes at least one additional plurality of hard coating layers including high and low refractive index layers and Herpin equivalent layers sandwiched therebetween. The additional plurality of layers has an associated second transmission band that substantially coincides with the first transmission band, but provides additional blocking at wavelengths outside the first transmission band. Relatively wide transmission bands and high blocking over an extended range of wavelengths can be achieved such that the filter is suitable for use in multiphoton fluorescence systems.

Abstract: A control system for one or more electrochromic elements used in an outside electrochromic (OEC) mirror used in automobiles or other vehicular applications, to control the glare of both IEC elements used as a rearview mirror (20) as well as the OEC elements (24, 26) used as sideview mirrors (24, 26). An ambient light senor (129) and glare sensor (133) operate to determine a glare level used to control both IEC and OEC electrochromic elements. The drive circuits for the OEC's elements may be controlled so as to account for various factors such as tinted glass characteristics in the vehicle.

Abstract: A synthetic micro-optic system and security device is disclosed including an in-plane image formed of an array or pattern of image icons and an array of focusing elements, the system producing at least two different synthetic images whereby one synthetic image operates to modulate or control the extent of the appearance of another synthetic image. In an exemplary form, the array of image icons forms an in-plane synthetic image, while the interaction of the array of focusing elements with the array of image icons forms a separate synthetically magnified image that serves to control the field of view of the in-plane image and, thus, serves to modulate or control the extent of appearance of the in-plane image. The appearance of the in-plane image, thus, visually appears and disappears, or turn on and off, depending upon the viewing angle of the system.

Abstract: A solid state imaging device includes a semiconductor substrate with photodiodes, transfer electrodes on the semiconductor substrate, a light shielding film with openings above the photodiodes and covering the transfer electrodes, and inner lenses located above the openings. Each inner lens has an upper convex lens surface and a lower convex lens surface which projects into the opening. The lower convex lens surface has a light exit surface, at the bottom, which faces the photodiode. Except this light exit surface, the lower convex lens surface is covered with a reflective film. The upper convex lens surface converges the incident light on the inner lens to a diameter smaller than a maximum diameter of the lower convex lens surface. In the lower convex lens surface, the reflective film reflects the light to the light exit surface.

Abstract: An apparatus and its method of use by an observer to visually determine what, if any, distortions are introduced by unexpected curvature in a personal vanity mirror. The apparatus remains simple to operate and is convenient for casual use. By providing a familiar reference pattern against which to compare the image reflected by a mirror, the observer can make more well-informed decisions.

Abstract: In a scatterometry apparatus having an illumination aperture stop, a field stop is provided at an intermediate image to control the spot size on the substrate. The field stop may be apodized, e.g. having a transmissivity in the form of a trapezium or a Gaussian shape.

Abstract: A method of generating a high precision optical surface profile includes obtaining a high precision optical surface profile which contains information of the optical path difference map of the profile. A substrate material has a known index of refraction, Ns, while a cover material has an index Nc that is more closely matched to the index Ns of the substrate material than the index of air Nair to Ns. An exaggerated surface profile is cut that is proportionally expanded from the high precision profile by a factor: (Ns-Nair) divided by (Ns-Nc). The cut surface profile is covered with the cover material.

Abstract: A focusing group G1 is disposed on an object side relative to a variator group G2. The focusing group G1 includes, in order from the object side, a first group G11 having a positive refractive power, a second group G12 having a positive refractive power, and a third group G13 having a positive refractive power. The first group G11 has, in order from the object side, at least one concave lens (L11) and at least one convex lens. When focusing from an infinitely distant object to a close object, the second group G12 and the third group G13 are moved so that with respect to a change in an object distance, an amount of movement of the second group G12 becomes large in a region near infinity, while an amount of movement of the third group G13 becomes large in a close range.

Abstract: A lens barrel includes a communicating passage that communicates between a space inside the lens barrel and outside of the lens barrel. The communicating passage includes a through hole, a circumferential groove, and a vertical groove. Light from outside the lens barrel is prevented from entering an effective optical range of a lens through the communicating passage. A partition is arranged between the effective optical range and a non-light-transmitting range. A surface of a portion outside the effective optical range is formed of a light-absorbing material, so that light is prevented from directly entering the lens through the communicating passage.

Abstract: A vehicle camera and wide-angle objective lens system are disclosed wherein the wide-angle objective lens has image aberrations or errors that do not deteriorate the detection of obstructions or obstacles in its field of view.

Abstract: It is to provide an imaging lens that can sufficiently meet demands for size and weight reduction and further improvement in optical performance, and improve productivity. The imaging lens is used for forming an image of an object on an image-taking surface of a solid image sensor element and comprises, in order from an object side to an image surface side, a diaphragm, a first lens which is a meniscus lens having a positive power whose convex surface faces the object side, and a second lens which is a meniscus lens having a positive power whose convex surface faces the image surface side, wherein a condition expressed by the following expression is to be satisfied: 1.45?(r3+r4)/(r3?r4)?3.4 (where, r3: center radius curvature of the object side face of the second lens, and r4: center radius curvature of the image surface side face of the second lens).

Abstract: The invention relates to a light-receiving element for receiving light reflected at an optical recording medium capable of preventing qualitative deterioration of an electrical signal obtained by photoelectric conversion of the light received, an optical head using the element, and an optical recording/reproducing apparatus using the element. The light-receiving element includes a light-receiving portion formed on a silicon substrate, and a cover layer disposed so as to cover an upper side of the silicon substrate, the cover layer on the light-receiving portion having a thickness of 30 ?m or less as viewed in the normal direction of the silicon substrate surface.

Abstract: A method for fabricating an array of aligned optical elements. In one embodiment, the optical elements include primary and secondary mirrors that are used to concentrate sunlight onto a photovoltaic cell for direct conversion of the sunlight into electricity. The array is formed using a front panel of plate glass or other transmissive material. The glass sheet is registered with a base tool. Subsequent tools are also registered with the base tool to deposit the primary and secondary mirrors for fabrication of the array.

Abstract: An actuator includes at least one actuator unit. The actuator unit includes a ring, a plurality of first actuator elements, and a plurality of second actuator elements disposed on the ring. Each of the first actuator elements includes a first driving piece and a second driving piece attached to each other. The first driving piece is attached to the ring and is located between the second driving piece and the ring. A coefficient of thermal expansion of the first driving piece is larger than that of the second driving piece. Each of the second actuator elements includes a third driving piece and a fourth driving piece attached to each other. The third driving piece is attached to the ring and is located between the fourth driving piece and the ring. A coefficient of thermal expansion of the third driving piece is less than that of the fourth driving piece.

Abstract: A lens assembly has a driving actuator which includes a magnet, a yoke and a coil and is formed along a lens barrel that accommodates a lens unit for focusing and an auto-focus controlling apparatus comprises the lens assembly for camera module. The magnet or the coil has an internal diameter smaller than a maximal diameter of the lens barrel. Therefore, it is possible to manufacture much smaller lens assembly according to the present invention compared to the conventional ones and to reduce the possibility of component damages in the lens assembly in operating the camera module.

Abstract: A lens barrel which is capable of attaining further reduction of thickness and size of a lens barrel by making effective use of accommodation spaces for barrier blades. In the lens barrel, barrier blades openably covers an image-taking by changing over its position between an image-taking position and a standby position. Accommodation spaces receive the barrier blades therein, respectively, when they are open. When the lens barrel is switched from the image-taking position to the standby position, a rectilinearly-moving restriction barrel relatively moves closer to the barrier blades in an optical axis direction, and at this time, arch-shaped portions of the rectilinearly-moving restriction barrel enter the accommodation spaces.

Abstract: A rear view system for a transportation device includes a rear view means, a sensor and a controller. The sensor is used for generating a movement signal according to the movement of the transportation device. The controller is used for controlling the rotation of the rear view means according to the movement signal. Moreover, a method for adjusting the visual angle of a rear view means equipped in a transportation device is also disclosed.

Abstract: This invention relates to improvements in thermal management in deformable mirrors. In particular, this invention relates to a deformable mirror comprising a heat spreader used to distribute thermal energy evenly across the mirror. Diamond material 104, on account of its extremely high thermal conductivity, is a preferred choice of heat spreader which permits build up of thermal energy in the mirror 100 to be quickly and evenly distributed across the entire mirror surface, increasing the working life of the mirror.

Abstract: A variable shape mirror includes a support substrate, a mirror substrate that is opposed to the support substrate, a fixing member that is disposed on the support substrate and fixes the mirror substrate, and a piezoelectric element that is disposed on the support substrate and is expanded or contracted so that a reflection plane of the mirror substrate can be deformed. A coefficient of linear expansion of the fixing member is larger than a coefficient of linear expansion of the piezoelectric element. A back surface of the mirror substrate is provided with a metal bonding layer that is disposed in at least a portion to be bonded to the fixing member. The metal bonding layer enables the mirror substrate and the fixing member to be bonded to each other by pressing the mirror substrate and the fixing member to each other while they are heated. The mirror substrate and the piezoelectric element are not bonded to each other.

Abstract: A variable shape mirror includes a support substrate, a mirror substrate that is opposed to the support substrate, a fixing member that is disposed on the support substrate and fixes the mirror substrate, and a piezoelectric element that is disposed on the support substrate and is expanded or contracted so as to deform a reflection plane of the mirror substrate. A bonding layer for bonding the mirror substrate and the fixing member to each other is provided to the surface of the mirror substrate opposite to the surface on which the reflection plane is formed, and the bonding layer is formed in an area that corresponds to the outside of an incident area of a light beam that enters the reflection plane.

Abstract: A manufacturing method for variable shape mirrors, which is suitable for mass production, includes a bonding step for sandwiching support pillars and piezoelectric elements between a support substrate and a mirror substrate, and bonding at least the support substrate and the support pillar to each other, the support substrate and the piezoelectric element to each other, and the mirror substrate and the support pillars to each other, respectively, and an elastic film forming step for forming a flat elastic film on the outer surface of the mirror substrate, and a reflection film forming step for forming a reflection film on the elastic film.

Abstract: A mount for an optical component is disclosed that provides the flexibility of independently adjusting the position and orientation of the optical component along and about one or more axes. In an exemplary embodiment, the mount includes a support element for supporting the optical component; one or more rotational adjustment elements for rotating said support element independently about one or more axes, respectively; and one or more linear adjustment elements for moving said support element independently along one or more axes. The adjustment elements may be manually adjustable and/or may be adjustable by an actuator. In the latter case, the actuator may be electronically controlled by a controller. The optical component may be a reflective, transmissive, or reflective/transmissive optical device, such as diffraction gratings, mirrors, beam splitters, and others.

Abstract: This invention provides an audio reproducing apparatus which reproduces plural digital audio signals and synchronizes them with each other. The audio reproducing apparatus includes a synchronization setting unit 11 which synchronizes the plural audio signals by allocating, on a time axis, plural pieces of audio reproduction time information of the audio signals and in a manner which maintains a difference between reproduction times indicated by adjacent pieces of the audio reproduction time information of each of the audio signals, and an audio synthesis unit 6 which synthesizes the plural audio signals using the plural pieces of the audio reproduction time information allocated on the time axis.

Abstract: A method for operating a tester for testing heads and disks of a magnetic recording disk drive during manufacturing calculates the readback signal amplitude asymmetry in the frequency domain without the need for measurement in the time domain with a peak detection channel. The tester first signals the write head to write a first pattern on the disk to generate a readback signal with positive pulses. The read head then detects this first recorded pattern and sends the readback signal to a spectrum analyzer connected to the tester. The tester then signals the write head to write a second pattern on the disk to generate a readback signal with negative pulses. The read head then detects this second recorded pattern and sends the readback signal to the spectrum analyzer. The spectrum analyzer measures the amplitudes of the first and second readback signals in the frequency domain using a bandpass filter.

Abstract: To measure the nonlinear distortion of a magnetic disk even at a high recording density, a nonlinear transition shift and a partial erasure are separately measured. A periodic pattern containing dibits and isolated bits, and a periodic pattern consisting only of isolated bits, are written and read in synchronism with the rotations of the magnetic disk. The reproduced waveforms of the respective periodic patterns are frequency-analyzed in a state where the phases of the periodic patterns are in agreement, thereby to obtain odd-numbered order harmonic components. The partial erasure and the nonlinear transition shift are evaluated on the basis of the ratio between the odd-numbered order harmonic components.

Abstract: A magnetic head having a tape bearing surface according to one embodiment includes a plurality of writers, each writer having first and second poles each having a pole tip positioned towards the tape bearing surface, a front gap defined between the pole tips, and a back gap defined along an electrical coupling of the poles at portions thereof positioned away from the tape bearing surface; wherein widths of the front and back gaps are defined in a direction parallel to the tape bearing surface and parallel to planes of deposition thereof, wherein a ratio of the width of the back gap to the width of the front gap is less than about 3:1. Various embodiments of a magnetic recording tape are also disclosed.

Abstract: Methods and systems for reducing read/write head track misregistration are described. According to one embodiment, a first signal is received from a first capacitive sensor that faces a surface of a disk associated with a disk drive. A second signal is received from a second capacitive sensor that faces the surface of the disk. A determination is made as to whether the disk is being moved along its axis of rotation or whether the disk is tilting. Read/write head track misregistration is reduced based on the determination of whether the disk drive is being moved along an axis of rotation or whether the disk is tilting.

Abstract: A control system controlling the tilt actuator and the tray motor of a optical disk drive includes a control device including a control unit generating control signals and a selection unit outputting a selection signal. A signal amplifier coupled to the control unit amplifies signals from the control unit. A de-multiplexer has an input node coupled to the signal amplifier and a control node coupled to the selection unit. A tilt actuator coupled to the first node of the de-multiplexer controlling the tilt angle of a pick-up head and a tray motor coupled to the second node of the de-multiplexer.

Abstract: A device and method for adjusting a distance between a magnetic head and a data storage medium are provided. In the device, a microprocessor outputs a control signal for adjusting the distance to a pre-amplifier based on a correlation between a flying height (FH) and a coefficient of a fifth tap of an adaptive digital filter included in a read/write (R/W) channel circuit or a correlation between the FH and a discrete Fourier transformed third harmonic signal output from the R/W channel circuit. The pre-amplifier outputs a voltage or current for flying on demand (FOD) to the magnetic head based on the control signal. The magnetic head adjusts the distance in real time based on the voltage or current for FOD.

Abstract: A method and apparatus to safely repress disturbances from being applied to a system from the surroundings in which the system is used. The method of adaptively repressing disturbances includes estimating frequency components of a disturbance applied to a system in a user environment; and optimizing parameter values determining characteristics of a disturbance compensating servo control loop including a disturbance observer, based on the estimated frequency components of the disturbance.