Abstract: An optical scanning device includes a mirror that oscillates to scan incident visible light. The mirror includes a substrate, a metal film formed on the substrate, and an reflection enhancing film stacked on the metal film.

Abstract: An optical reflection element according to the present invention includes a fixed frame, a pair of first oscillation parts, a movable frame, a pair of second oscillation parts, and a mirror part. One-side ends of the first oscillation parts are connected to the inside of the fixed frame. The movable frame is connected to and held by the other-side ends of the pair of first oscillation parts to be pivotable. One-side ends of the pair of second oscillation parts are connected to the inside of the movable frame and the pair of second oscillation parts are disposed to be substantially perpendicular to the pair of first oscillation parts. The mirror part is connected to and held by the other-side ends of the pair of second oscillation parts to be pivotable. The second oscillation parts have a meandering shape in which a plurality of straight portions and a plurality of folded portions are formed, and a stepped structure portion is provided in part of the folded portion.

Abstract: A vibrating mirror element includes a drive control portion configured to control the driving of a correction drive portion to keep the turning angle velocity of a mirror portion substantially constant by oscillating the mirror portion about an axis at a non-resonance frequency in a direction opposite to a direction in which a resonant drive portion oscillates the mirror portion.

Abstract: In an optical deflector apparatus, an optical deflector chip includes a mirror, an actuator adapted to rock the mirror, and first pads on a front surface of the optical deflector chip and connected to the actuator. A first substrate includes second pads on a back surface of the first substrate, and an opening is formed in the first substrate. The front surface of the optical deflector chip is adhered to the back surface of the first substrate in such a way that the first pads of the optical deflector chip are in contact with respective ones of the second pads of the first substrate and the mirror opposes the opening. A back surface of said optical deflector chip is adhered to a front surface of a second substrate.

Abstract: A light field display device comprising an array of light field display elements, each display element comprising: a beam generator for generating an output beam of light; a radiance modulator for modulating the radiance of the beam over time; a focus modulator for modulating the focus of the beam over time; and a scanner for scanning the beam across a two-dimensional angular field, the scanner comprising a biaxial electromechanical scanning mirror comprising: a mirror, a platform, an inner frame, and an outer frame; the mirror attached to the platform via a post, the platform attached to the inner frame via a first pair of hinges, and the inner frame attached to the outer frame via a second pair of hinges; the first pair of hinges arranged substantially orthogonally to the second pair of hinges, thereby to allow biaxial movement of the mirror; the extent of the mirror larger than the extent of the inner frame.

Abstract: Provided is a light-scanning device may be designed to have a high resonance frequency and a large scanning angle. A mirror unit vibrates by using an arbitrary straight line as a rotation axis. A pair of first beam portions are disposed on a straight line that is parallel to the rotation axis, and support the mirror unit. A pair of second beam portions are disposed so as to be line-symmetrical to the pair of the first beam portions about the rotation axis as an axis of symmetry, and support the mirror unit. A pair of first arm portions respectively support the pair of first beam portions. A pair of second arm portions respectively support the pair of second beam portions. A pair of third beam portions support the mirror unit between the first beam portions and the second beam portions.

Abstract: An optical scanning device includes an oscillating mirror part, a torsion bar part, a piezoelectric element (driving part), a housing, and an optical element part. The oscillating mirror part includes a reflective surface capable of reflecting light from a first light source and a mass adjustment part formed on an opposite surface of the oscillating mirror part to the reflective surface and configured to be capable of reducing a mass thereof by exposure to laser light. The torsion bar part supports the oscillating mirror part. The piezoelectric element is configured to torsionally oscillate the oscillating mirror part about the torsion bar part. The housing accommodates the oscillating mirror part, the torsion bar part, and the piezoelectric element. The optical element part is configured to reflect or transmit the laser light from a second light source disposed outside of the housing to expose the mass adjustment part to the laser light.

Abstract: A magnetic force drive device (7) has the first movable part (100) and the first driving unit (200). The first movable part (100) has the first movable plate (111), and a permanent magnet (120) that is magnetized in a direction substantially parallel to the first movable plate (111), and is supported by the first frame body (112) and the first pair of beam parts (113), so as to be able to oscillate around the Y axis, which is substantially parallel to the first movable plate (111) and substantially perpendicular to the direction in which the permanent magnet (120) is magnetized. The first driving unit (200) has a yoke (210), and a coil (220) that magnetizes the yoke (210). The yoke (210) has the first end part (211a), and a second end part (212a) that is placed on substantially the opposite side of the first end part (211a) against one magnetic pole of the permanent magnet (120).

Abstract: Motion control system and method for biosensor scanning that include inputting to a multi-axis motion controller move commands associated with the scan path as defined by multiple axes. The multiple axes including an x-baseline coordinate x0, a y-baseline coordinate y0, an x-direction oscillation amplitude x1, a y-direction oscillation amplitude y1, an oscillation frequency f and a phase ?. The multi-axis motion controller outputs digital commanded positions for each of the multiple axes. A post-processor receives the commanded positions and generates parameterized commanded positions x and y that each include a baseline motion component and an oscillating motion component. The parameterized commanded positions cause the scanning optical system to deflect the light beam to scan the beam spot over the scan path to scan the biosensor.

Abstract: A light scanning apparatus includes torsion beams supporting a mirror supporting portion on opposite sides of the mirror supporting portion along an axis direction, the mirror supporting portion being swung around the axis direction by the torsion beams; a pair of drive beams sandwiching the mirror and the mirror supporting portion in a direction orthogonal to the axis direction; connection beams that connect mutually facing sides of each drive beam with the torsion beams; and a piezoelectric sensor formed on the connection beams and detecting displacement of the connection beams caused by a swing of the torsion beams around the axis when the mirror swings by a drive voltage, wherein a first bias voltage having a positive or negative polarity is applied to an upper electrode of the piezoelectric sensor, and a second bias voltage having an opposite polarity is applied to a lower electrode.

Abstract: In a MEMS device (1), a first drive portion (40) is divided into a first drive section (41) and a second drive section (42). A second drive portion (50) is divided into a third drive section (51) and a fourth drive section (52). The first drive section, the second drive section, the third drive section, and the fourth drive section are controlled for driving independently of each other to incline an optical component (10).

Abstract: A micromechanical component has a light window; a mirror element adjustable with respect to the light window from a first position into at least one second position about at least one axis of rotation, an optical sensor having a detection surface designed to ascertain a light intensity on the detection surface and to provide a corresponding sensor signal. The light window, the mirror element in the first position and the detection surface are situated in relation to one another in such a way that a portion of a light beam reflected on the light window strikes the detection surface at least partially; and an evaluation unit designed to define, on the basis of the sensor signal, information regarding an instantaneous position of the mirror element and/or an instantaneous intensity of the deflected light beam.

Abstract: A scanning beam projection system includes a scanning mirror having a fast-scan axis and a slow-scan axis. Movement on the fast-scan axis is controlled by a fast-scan scanning mirror control system. The control system receives position information describing angular displacement of the mirror. A fast-scan drive signal is generated that causes the scanning mirror to oscillate at a resonant frequency with a varying amplitude.

Abstract: An imaging device scan unit, including an oscillator oscillating in a predetermined oscillation pattern; a light source generating a light beam for deflection by the oscillator and including a forward sweep portion when the oscillator moves in a first direction of the oscillation pattern and a reverse sweep portion when the oscillator moves in a second direction different from the first direction thereof; and components defining at least two optical paths for the light beam, the forward sweep portion of the light beam passes through a first optical path and the reverse sweep portion of the light beam passes through a second optical path, the second optical path reverses a sweep direction of the reverse sweep portion of the light beam such that the forward sweep portion and the reverse sweep portion of the light beam are in the substantially same direction when exiting the scan unit.

Abstract: Provided is a Micro-Electro-Mechanical Systems (MEMS) device for actuating a gimbaled element, the device including a symmetric electromagnetic actuator for actuating one degree of freedom (DOF) and a symmetric electrostatic actuator for actuating the second degree of freedom.

Abstract: An optical scanning device, having: a substrate main body; two cantilever beams protruded from the respective side portion of one side of the substrate main body; a mirror supported by torsion bars from the respective side, between the cantilever beams; a drive source to causes the substrate main body to vibrate; and a light source to project light onto the mirror, wherein a fixed end of the substrate main body is fixed to a supporting member, on the opposite side from the mirror side, and wherein the mirror resonantly vibrates according to vibration applied to the substrate by the drive source, thereby to change a direction of reflection light of the light projected onto the mirror from the light source according to the vibration of the mirror, characterized in that a Si mirror is attached to and fixed on the mirror.

Abstract: An optical reflection element includes a frame, a meandrous vibrating part having an outer end connected with an inside of the frame, and a mirror part supported by an inner end of the meandrous vibrating part. The meandrous vibrating part has a meandrous shape that includes curved portions and vibrating beams alternately connected with the curved portions. A curvature of respective one of the curved portions is smaller than a curvature of at least one of the curved portions which is located closer to the inner end than the respective one of the curved portions. This optical reflection element has a large deflection angle of the mirror part.

Abstract: A display system includes a substrate guided relay and a scanning projector. The scanning projector exhibits a brightness variation on a resonant scanning axis, and the substrate guided relay exhibits a brightness variation along a length of an output coupler. The scanning projector includes a brightness compensation circuit to compensate for both the brightness variation caused by the resonant scanning and the brightness variation along the length of the output coupler.

Abstract: A component having a mounting support, a displaceable part, which is joined to the mounting support by at least one flexible joining component, and an actuator device. The actuator device is configured to set at least one subunit of the displaceable part and/or of the at least one flexible joining component into a first oscillatory motion along a first axis in such a manner, that the displaceable part may be set into an angular oscillatory motion about a first rotational axis. The actuator device is additionally configured to set the same and/or another subunit into a second oscillatory motion having a motion component along a second axis at an inclination to the first axis, in such a manner, that, in addition to the angular oscillatory motion, the displaceable part is displaceable about a second rotational axis.

Abstract: Disclosed is an optical scanning device, including a mirror, a first drive beam configured to swing the mirror around a first axis, and a second drive beam configured to swing the mirror around a second axis, wherein the second drive beam is provided in such a manner that a plurality of beams extending in a direction intersecting with a direction of the second axis are joined with adjacent beams at edge portions thereof, and thereby has a zigzag shape, and each of the plurality of beams includes a rib extending in a direction of a width of the beam.

Abstract: A mirror axis (MA) is displaced by deformation of a holder (HD) and with resonance of an optical scanner (LS) itself according to the frequency of a voltage applied to a piezoelectric element (PE). The frequency of the applied voltage for causing a resonance deforms the holder (HD) so as to generate at least one node intersecting with respect to the length of the holder (HD) itself.

Abstract: An image forming apparatus includes a light output unit that outputs light and a light scanning unit that includes at least one light reflection part reflecting the light output from the light output unit, and scans a display surface in a first direction at a first speed and scans the surface in a second direction orthogonal to the first direction at a second speed lower than the first speed with the light reflected by the light reflection part, wherein a drawable region in which an image can be formed on the display surface by scanning with the light has at least two parts of a part in which a length of the drawable region in the first direction increases, a part in which the length decreases, and a part in which the length is maintained constant from a first side toward a second side in the second direction.

Abstract: In a moving structure, stability of swing motion of a moving plate is increased by enhancing tensional rigidity or flexural rigidity while restraining torsion rigidity of the hinge units. The hinge units of ladder shape with honeycombed portions are formed by twin supporting rods and crosspieces bridged between the twin supporting rods so as to support the moving plate rotatably. The tensional rigidity or the flexural rigidity is increased while restraining the torsion rigidity of the hinge units by the honeycombed portions of the hinge units.

Abstract: A taut-band resonant scanner is disclosed that includes an elongated band and a sub-assembly. The elongated band has a length in an elongated direction, a width in a width direction that is orthogonal to the elongated direction, and a thickness in a thickness direction that is orthogonal to both the width direction and the elongated direction, wherein the thickness is substantially smaller than the width and wherein the width direction and elongated direction define a band width/length plane. The sub-assembly is attached to a portion of the band, and includes at least one mounting structure.

Abstract: An optical scanning device includes: a first scanning; a first scanning mirror driving unit; a light emission signal output unit; a light receiving unit; and a phase control unit which controls the first scanning mirror driving unit so as to delay a phase of the oscillation of the first scanning mirror when the light receiving unit outputs the detection signal before intermediate time in a case where the light receiving unit does not output the detection signal during a predetermined period of time, the phase control unit controlling the first scanning mirror driving unit so as to advance a phase of the oscillation of the first scanning mirror when the light receiving unit outputs the detection signal after the intermediate time in the case where the light receiving unit does not output the detection signal during the predetermined period of time.

Abstract: The power and response curves of one or more beams or primaries of beams of a laser projection system illuminating an image on a viewing surface are controlled to desired characteristics during exhibition by monitoring the scanning beams in real time by using at least part of the horizontal blanking time during the scanning of a motion or still image to project a test pattern with one or more of the beams onto a sensor or sensors. The system and method permits real-time balancing and maintenance of the response curves and power levels of each of the beams, and of primary beams of combined beams, to desired targets so as to produce a display field without artifacts and at desired brightness on the viewing surface.

Abstract: Implementations of actuators and capacitor-based position sensors for monitoring and controlling positioning of the actuators are provided, including implementations of actuators that use flexures to provide support to actuators and pivoting mechanisms to the actuators. Such actuators can be electromagnetically activated actuators that include a magnet stator and a coil rotor mounted on a flexure. A positioning sensor, such as a capacitor sensor, is provided to measure and monitor positioning of the actuator and is coupled to a feedback circuit which uses the measured positioning of the actuator to control the actuator.

Abstract: The oscillation element according to the present invention includes a torsion bar mounted on a base, and an oscillating member having a light reflection surface for reflecting light from a light source, which is fixed on the torsion bar protruding from the base. The oscillating member oscillates about a longitudinal axis of the torsion bar with an elastic deformation of the torsion bar, thereby deflecting the light that reflects at the light reflection surface in a direction intersecting the longitudinal axis. The oscillating member has two plates that are joined together so as to sandwich the torsion bar. On joining surfaces of the plates are provided with grooves for receiving the torsion bar, respectively. The plates have a symmetrical shape that the longitudinal axis serves as the axis of symmetry.

Abstract: In a wavelength swept light source using a polygon mirror in a well-known art, an oscillation wavelength roughly linearly varies in an upwardly slight convex shape with respect to time. On the other hand, in a wavelength swept light source of SS-OCT, the wavelength is required to vary so that a wavenumber (inverse of wavelength) linearly varies on a time axis. The wavelength swept light source of the well-known art has had a drawback that such wavelength variation cannot be implemented; non-linear distortion occurs in a resultant OCT image; and thereby, a point spread function cannot be kept sharp.

Abstract: The present invention is a sweeping or reciprocating laser scanning device. The reciprocation or sweeping motion is cam driven. As the cam rotates, a lever arm is reciprocated or oscillated between two positions, which causes the laser or beam of light to move linearly, thus creating a triangular plane of light resulting in a reciprocating linear reference across the hypotenuse of the triangular plane of light.

Abstract: Optical scanning device 10 according to the present invention includes: plate-like movable mirror 11 having reflection surface 12 for reflecting light on one surface, and piezoelectric unit 13 including a plurality of piezoelectric elements on the other surface; a pair of torsionally deformable torsion beams 2 and 3 arranged opposite to each other at both ends of movable mirror 11 and swingably supporting movable mirror 11; driving units 4 and 5 for driving movable mirror 11 to oscillate; and compensating voltage application means 8 for applying a compensating voltage that is an alternating-current voltage to piezoelectric unit 13 when movable mirror 11 oscillates, thereby causing compensatory deformation in movable mirror 11 to compensate for deformation that occurs in movable mirror 11 due to the oscillation of movable mirror 11.

Abstract: An optical scanner capable of preventing breakage of a shaft section due to stress concentration is provided. A mirror frame 13 is shaped so as to enclose a mirror 11, and holds the mirror 11, via torsion bars 121 and 122, so as to be vibratable. A unimorph 15 is constituted by four unimorphs 151, 152, 153, and 154 formed on upper left, lower left, upper right, and lower right sides, and holds the mirror frame 13, via a shaft section 14, so as to be vibratable. The shaft section 14 has a connection section 144. On the mirror frame 13, an adjustment member 16 for increasing a moment of inertia m1 of the mirror frame 13 is provided.

Abstract: An optical scanner includes a light source, a scan-deflecting portion including a resonance mirror to scan and deflect along a scan line, a plurality of light receiving sensors for synchronous detection provided on the scan line, a phase controller, an amplitude controller, and an offset controller. The phase controller obtains a difference between a true phase and a target phase, and generates a drive signal incorporating the difference between the true phase and the target phase. The amplitude controller incorporates the difference between a value equivalent of a true amplitude and a value equivalent of a target amplitude into the drive signal generated by the phase controller. The offset controller calculates an offset value by obtaining the difference between each of the time intervals, incorporates the difference between the offset value and a target offset value in the amplitude-controlled drive signal, and supply the drive signal to a driving device.

Abstract: A module configured to deflect light in an image forming apparatus. A torsion bar supports a mirror and defines a rotational axis of the mirror. A controller is configured to apply electronic pulses to at least one driving device to oscillate the mirror in the module around the rotational axis at a scanning frequency different than a resonance frequency of the mirror.

Abstract: A scanning projector includes a MEMS device with a scanning mirror that sweeps a light beam in two dimensions. A laser limit comparison circuit determines a metric from measured peak scan angles and measured light output. The metric is compared to a threshold and a light source is shut down when the metric exceeds the threshold.

Abstract: This vibrating mirror element includes a mirror portion reflecting light, a torsionally deformable beam portion connected to the mirror portion for supporting the mirror portion in a vibratile manner, and a driving portion having a connecting portion connected with the beam portion for driving the mirror portion through the torsionally deformable beam portion. The width of the connecting portion of the driving portion is rendered smaller than the width of a portion of the driving portion other than the connecting portion in plan view.

Abstract: A MEMS device includes a mirror substrate (200), an electrode substrate (301) arranged so as to face the mirror substrate (200), a mirror (230) serving as a movable member rotatably supported in an opening portion of the mirror substrate (200) via support members, a driving electrode (101) arranged on an insulating film (104) on a surface of the electrode substrate (301) facing the mirror substrate (200) so as to face the mirror (230) across a gap and drive the mirror (230), and a lower electrode (103) made of a metal or a semiconductor and formed under the insulating film (104) exposed to the gap so as to be in contact with the insulating film (104).

Abstract: An optical reflection element has a frame-shaped supporting body, a first oscillator and a second oscillator each having a meander shape, and a mirror portion. A line segment connecting a joining position between the mirror portion and the first oscillator to a joining position between the supporting body and the first oscillator, and a line segment connecting a joining position of the mirror portion and the second oscillator to a joining position of the supporting body and the second oscillator cross a mirror portion central axis. As one illustrative condition to be satisfied, an outer circumference of at least any one of turn portions of the first oscillator and the second oscillator is deviated from a first end portion axis that is parallel to the mirror portion central axis and extends along a first side of the mirror portion.

Abstract: A method of manufacturing an oscillator device having first and second oscillators being driven at first and second driving resonance frequencies gf1 and gf2, the method including a first step for processing the two oscillators, wherein, when the two oscillators are going to be processed as oscillators having first and second resonance frequencies different from the two driving resonance frequencies with a certain dispersion range, the two oscillators are so processed that the first and second resonance frequencies different from the two driving resonance frequencies become equal to first and second resonance frequencies f1 and f2, respectively, which are included in adjustable resonance frequency ranges, respectively, and a second step for adjusting the first and second resonance frequencies f1 and f2 so that they become equal to the first and second driving resonance frequencies gf1 and gf2, respectively.

Abstract: A biaxial scanning mirror for an image forming apparatus includes a first wafer, a second wafer, and a spacer. The first wafer includes a mirror unit, a rectangular rotating unit, a permanent magnet, and a magnetically permeable layer. The second wafer has at least two cores each surrounded by a planar coil applied with an AC current for switching magnetic polarization of the cores such that the cores are attracted to or repelled from the rotating unit alternatively, thereby driving the rotating unit to rotate.

Abstract: An image forming apparatus includes an optical scanning unit, a measurement unit, a first adjustment unit and a second adjustment unit. The optical scanning unit includes a plurality of light sources to emit laser beams, a single oscillating mirror deflector to deflect the laser beams used for scan processing in a main scanning direction, and a scan-focusing member to focus the deflected laser beams onto a plurality of photoconductors. The measurement unit measures a resonance frequency of the oscillating mirror deflector. The first adjustment unit adjusts a speed of the photoconductors in a sub-scanning direction. The second adjustment unit adjusts a magnification ratio of image data in the sub-scanning direction. The first adjustment unit and the second adjustment unit adjust the image magnification ratio of image data in the sub-scanning direction depending on the resonance frequency as measured by the measurement unit.

Abstract: A first oscillating portion is provided with a first piezoelectric element having a first drive electrode. A second oscillating portion has a central axis different from that of the first oscillating portion and is provided with a second piezoelectric element having a second drive electrode. The first drive electrode and the second drive electrode are connected together.

Abstract: A micro-structure produced by utilizing a MEMS technology or the like includes: a frame including a portion having a first layer and a portion having a second layer on the lower side of the first layer; a movable body including a portion having the first layer and a portion having the second layer; and at least one swing supporting portion which is having the first layer, and connects the portion having the first layer in the frame and the portion having the first layer in the movable body, to support the movable body to be capable of swinging. A frame side end portion of the swing supporting portion is supported from underneath by the portion having the second layer in the frame, and a movable body side end portion of the swing supporting portion is supported from underneath by the portion having the second layer in the movable body.

Abstract: An optical scanning apparatus includes a plate member, having a rotation axis and a reflection surface, that deflects and scans a laser beam emitted from a light source by performing reciprocating-rotation around the rotation axis, an actuator configured to drive the plate member, an f?-lens configured to focus the laser beam deflected by the plate member on a surface of a photosensitive drum, and an optical box configured to house the plate member, the actuator, and the f?-lens. The actuator is provided nearer to a side of the optical box toward which the laser beam is reflected by the reflection surface than the reflection surface of the plate member is.

Abstract: An apparatus includes a substrate and a mirror. The mirror is attached to the substrate via a spring. An electro-mechanical driver is operable to cause the mirror to rotationally oscillate about first and second non-collinear axes at different first and second frequencies.

Abstract: An optical scanning device includes an optical scanning element which has a reflection mirror and is configured to perform reciprocating scanning of an optical flux radiated from a light source by resonance oscillations of the reflection mirror; a photo detector which is arranged at a position which a portion of the optical flux scanned by the optical scanning element in a reciprocating manner passes in both outgoing-path scanning and incoming-path scanning, and is configured to output a pulse signal having a predetermined width at a point of time that the scanned optical flux is detected; and the reference signal generator which is configured to detect timing between rising edge timing of one pulse signal and falling edge timing of the other pulse signal out of two pulse signals continuously outputted from the photo detector, and to generate the reference signal based on intermediate timing between the edge timings.

Abstract: This vibrating mirror element includes a pair of first beam portions supporting a mirror portion in a vibratile manner, a pair of second beam portions connected with the pair of first beam portions respectively, and a pair of driving portions connected with the pair of second beam portions respectively. The mirror portion is arranged in a region surrounded by the pair of second beam portions and the pair of driving portions. The width of the pair of first beam portions and the width of the pair of second beam portions are rendered smaller than the width of the pair of driving portions.

Abstract: A laser projector is provided. A laser light source is configured to emit laser light. A scanning section is configured to scan a projection surface in a horizontal direction and a vertical direction with the laser light emitted from the laser light source, thereby forming an image on the projection surface. A generating section is configured to generate a pulse signal. A driving section is configured to reciprocate the scanning section in the horizontal direction in accordance with the pulse signal generated by the generating section. An adjusting section is configured to adjust a pulse pattern of the pulse signal generated by the generating section so as to change a scanning angle range of the scanning section in the horizontal direction.

Abstract: An illuminator includes: a light source section including a laser light source; an optical element through which a laser beam from the laser light source passes; a driving section oscillating the optical element; and a control section controlling, in a driving operation performed by the driving section, the driving operation to allow an oscillating amplitude value of the optical element in a startup period of the optical element to be equal to or less than the oscillating amplitude value of a steady-state operation period of the optical element that is subsequent to the startup period.

Abstract: Disclosed is an oscillator device that includes an oscillating system having a first oscillator, a second oscillator, a first torsion spring for connecting the first and second oscillators each other, and a second torsion spring being connected to the second oscillator and having a common torsional axis with the first torsion spring; a supporting system for supporting the oscillating system; a driving system for driving the oscillating system so that at least one of the first and second oscillators produces oscillation as can be expressed by an equation that contains a sum of a plurality of time functions; a signal producing system for producing an output signal corresponding to displacement of at least one of the first and second oscillators; and a drive control system for controlling the driving system on the basis of the output signal of the signal producing system so that at least one of amplitude and phase of the time function takes a predetermined value.