JP4695956B2 - Micro electromechanical modulation element, micro electro mechanical modulation element array, and image forming apparatus - Google Patents

Description

  The present invention relates to a microelectromechanical modulation element and a microelectromechanical modulation element array and an image forming apparatus having a movable part that is displaced in both directions, and more particularly to an improved technique for braking the movable part.

  2. Description of the Related Art In recent years, with the rapid advancement of MEMS technology (MEMS: Micro-Electro Mechanical systems), development of micro electromechanical modulation elements that electrically displace and move micro structures on the order of μm has been actively conducted. Examples of the micro electro mechanical modulation element include a digital micro mirror device (DMD) that tilts a micro mirror to deflect light. DMD is widely used in the field of optical information processing, such as projection displays, video monitors, graphic monitors, televisions, and electrophotographic prints.

  A microelectromechanical modulation element generally includes a movable portion that is supported so as to be elastically displaceable and that is displaced in both directions, and the movable portion mainly performs a modulation operation. Therefore, the braking control of the movable part is particularly important for good switching operation.

  For example, a micromirror device disclosed in Patent Document 1 below applies a voltage to one electrode of a pair of drive electrodes, and a movable part having a mirror disposed by hinge connection between these electrodes is defined as a drive electrode. It is made into the structure rotated by the electrostatic attraction according to the electric potential difference and electrostatic capacitance between.

  In addition, a method for attenuating a ribbon element in a micromechanical lattice device disclosed in Patent Document 2 below defines an electromechanical ribbon element on a channel having a bottom surface and having a bottom conductive layer formed below the bottom surface. In the damping method, providing at least one constant amplitude voltage pulse to at least one ribbon element and providing at least one braking pulse separated from the constant amplitude voltage pulse by a narrow temporary gap to the ribbon element. And have. That is, a driving voltage for causing the electrostatic force to act in a single direction and pulling the ribbon element toward the lower electrode side by one movable part electrode and one fixed electrode of the parallel plate system element, and an initial application immediately before the driving voltage The vibration is to be controlled by two braking drive voltages, that is, a braking voltage or a final braking voltage applied immediately after the driving voltage.

  An optical path switching device disclosed in Patent Document 3 includes a mechanical optical switch that switches a light path by applying a signal voltage to an electromagnetically driven actuator, and a control circuit that supplies the signal voltage to the optical switch. The signal voltage is 2/3 VH or less with respect to the rising amplitude VH and the signal width T of the signal when T / 2 has elapsed from the rising edge of the signal. In the signal voltage applied to the actuator, when T / 2 has elapsed from the rise of the signal of the vibration width T, the signal voltage is reduced to 2/3 times or less of the rise amplitude to suppress vibration.

  Further, in the method for controlling a micromachine element disclosed in Patent Document 4 below, the first control signal and the second control signal are supplied to the micromachine element, and the second control signal sets the micromachine element to an active state. The first control signal is configured to maintain this state. Then, the micromachine element is controlled using the control signal for setting the micromachine element to the pull-in state, the other control signal for holding the micromachine element in the pull-in state, and at least two control signals. This enables control of the micromachine element at a low voltage level.

JP-A-8-334709 JP 2001-174720 A JP 2002-169109 A JP 2002-36197 A

  However, in the micromirror device disclosed in Patent Document 1, a voltage is applied to one of the drive electrodes to generate an electrostatic attraction according to the potential difference and capacitance between the movable part and the drive electrode, Rotate the moving part. For this reason, as shown in FIG. 21A, vibration is generated by receiving a reaction force from the contact member immediately after the micromirror transits to the contact position by application of the voltage Va and lands on the contact position. Further, even in the case of a non-contact structure in which the micromirror does not land at the contact position, as shown in FIG. 21 (b), the overshoot occurs beyond the desired rotation angle (convergence position), thereby causing vibration. It took time to calm down. These vibrations and overshoots have hindered speeding up in the switching operation of the microelectromechanical modulation element.

  In the micromechanical lattice device disclosed in Patent Document 2, as shown in FIG. 22A, the constant amplitude voltage pulse 1 is a function of time, and has a duration of 2 μsec and a voltage value of 10V. Immediately after the constant amplitude voltage pulse 1, a narrow braking pulse 5 separated from the constant amplitude voltage pulse 1 by a narrow gap 3 is applied. Furthermore, as shown in FIG. 22B, when the adjacent constant amplitude voltage pulse 7 has the opposite polarity, the polarity of the braking pulse 9 is also opposite to the related voltage pulse 7. However, this micromechanical lattice device is a so-called parallel plate type microelectromechanical modulation element that translates a ribbon that is a movable portion in parallel to the substrate side, and includes one movable portion side electrode and one fixed side that faces the movable portion side electrode. Since braking is performed by applying pulses to the electrodes, there is a disadvantage that the diversity of vibration control methods is poor. For example, when the movable part is displaced by suction with respect to the substrate, a braking force in the opposite direction cannot be applied simultaneously. In other words, vibration could not be reduced actively.

  Further, the optical path switching device disclosed in Patent Document 3 reduces the attractive force due to the coil magnetic field when the movable part approaches the tip of the yoke, that is, when the attractive force due to the permanent magnet magnetic field becomes strong in an electromagnetically driven actuator. The movable part is moved to the fiber connection position so that the total suction force does not become too strong. As shown in FIG. 23A, the waveform output by the signal generation circuit is a signal voltage that rapidly decreases after rising at a rising voltage VH = 7V. The signal width T is 5 ms, and the signal termination voltage is 0.5V. The voltage after lapse of T / 2 from the rising edge is 2.8v. In FIG. 23B, the rising voltage is 7 V, the signal width T is 5 ms, and the time TO when the amplitude changes stepwise is TO = 1.5 ms. In FIG. 23C, the rising voltage is 5 V, and the time T until the reduced amplitude becomes 1 V is 2 ms. Time T corresponds to the signal width. After time T, the voltage of 1V is continuously applied until the next switching is performed. FIG. 23 (d) shows a waveform in which the amplitude decreases stepwise to a constant value of 0.5V at a rising voltage of 5V and a time TO = 3ms until the stepped amplitude changes. These signal voltages increase the rising amplitude to speed up the movement (switching speed) of the movable part, and when the movable part begins to move, the signal voltage is sharply reduced to reduce the force applied to the movable part. Could be suppressed. However, this optical path switching device displaces the block that is the movable part in both directions in parallel, but it is trying to suppress vibration by changing the driving force acting in the forward direction, so the diversity of vibration control methods is poor. There was a disadvantage. In addition, basically the attraction force by the coil magnetic field is reduced and the signal voltage is reduced so that the total attraction force does not become too strong, and as described above, the vibration cannot be actively reduced.

  The micromachine element control method disclosed in Patent Document 4 performs control using one or more control signals. Typical waveforms of this control signal are shown in FIGS. 24 (a) to (h). As can be seen from FIGS. 24A and 24B, the control signal may be a pulse train that changes the state of the micromachine element. Similarly, in the case of at least two control signals, these signals are superimposed signals shown in FIGS. 22C and 22D and amplitude modulation (AM) signals shown in FIG. Or the frequency modulation (FM) signal depicted in FIG. 24 (f), the pulse width modulation (PWM) signal depicted in FIG. 24 (g), or as depicted in FIG. 24 (h). It may be a signal synthesized in a simple pulse density modulation (PDM) signal. However, this control method has the purpose of reducing the holding voltage in the pull-in state, reducing the on / off delay due to the discharge of the residual charge, increasing the amplitude of the output signal, etc., and can actively reduce the vibration. could not.

  The present invention has been made in view of the above situation, and a microelectromechanical modulation element and a microelectromechanical device capable of actively reducing a vibration of a movable part by applying a physical attractive force in a direction opposite to a transition direction of the movable part. An object of the present invention is to provide an optical modulation element array and an image forming apparatus, and to increase the switching operation speed.

In order to achieve the above object, a microelectromechanical modulation element of the present invention includes a movable portion that is supported so as to be elastically displaceable and that is displaced in both directions of a first direction and a second direction. A first electromotive force modulator that applies a physical acting force to the movable portion to displace the movable portion in the first direction; and the movable portion in the second direction. the physical acting force for displacing and a second drive source applied to the movable portion, said movable portion by adding the physical acting force against said movable part by said first drive source the braking upon displacing the first direction, while the movable portion is transitioning to the first direction, the movable portion by adding the physical acting force to the movable part by a second drive source characterized in that it.

  In this microelectromechanical modulation element, a physical attractive force acts in the direction opposite to the transition direction during the transition before the movable part reaches the final displacement position, and immediately before the movable part reaches the final displacement position. Will slow down. As a result, vibration due to a collision that occurs when the movable portion reaches the final displacement position at a high speed and overshoot when reaching the final displacement position by non-contact driving are suppressed. That is, vibration at the time of contact of the movable part can be actively reduced.

Further, in the micro electro mechanical modulation element of the present invention, the movable portion is displaced in the first direction and brought into contact with the stop member, and then the movable portion is caused by a reaction force due to contact with the stop member. During the transition to the second direction, a physical acting force is applied to the movable part in the first direction by the first driving source.

  In this microelectromechanical modulation element, the movable portion is driven to move in the first direction, and after reaching the final position of the displacement, the movable portion is further moved in the second direction by a reaction force or an elastic force caused by contacting the stop member. During the transition to, the physical acting force in the first direction is applied to the movable part, so that the movement of the movable part to be separated from the final position of the displacement is actively braked.

The micro electro mechanical modulation element of the present invention is characterized in that the physical action force is applied to a plurality of action points of the movable part.

  In this microelectromechanical modulation element, since there are a plurality of action points, for example, in a swing type movable part whose center is the rotation center, physical action force is applied to both sides sandwiching the rotation center. As a result, braking forces of different magnitudes can be applied to the respective action points at different timings, and various braking effects can be obtained.

The micro electro mechanical modulation element of the present invention is characterized in that when the movable part reaches the final position of displacement in a specific direction, the speed of the movable part becomes substantially zero.

  In this micro electromechanical modulation element, the speed at the moment when the movable part arrives at the final displacement position becomes substantially zero, and the vibration caused by the collision caused by the conventional movable part reaching the final displacement position at a high speed, No overshoot occurs when reaching the final displacement position in the case of contact drive.

The micro electro mechanical modulation element of the present invention is characterized in that the physical acting force is an electrostatic force.

  In this microelectromechanical modulation element, a high-speed vibration suppressing force can be obtained because the physical acting force that displaces the movable portion becomes an electrostatic force.

The micro electro mechanical modulation element of the present invention is characterized in that the physical acting force is applied in a pulse waveform with the intensity on the vertical axis and the time on the horizontal axis.

  In this microelectromechanical modulation element, the physical acting force is generated in the voltage range specified by the pulse waveform, and various braking effects can be obtained. Here, the pulse waveform includes a rectangular wave, a sine wave, a cosine wave, a sawtooth wave, a triangular wave, and a synthesized wave thereof.

The micro electro mechanical modulation element of the present invention is characterized in that the physical acting force is generated by a plurality of pulse waveforms.

  In this micro electromechanical modulation element, physical acting force is applied at different magnitudes and at different timings, and various braking effects can be obtained.

The micro electro mechanical modulation element of the present invention is characterized in that two or more physical acting forces can be set in each transition direction of the movable part.

  In this microelectromechanical modulation element, for example, in an oscillating type movable portion whose center is the rotation center, two or more physical acting forces are applied to each side of both sides sandwiching the rotation center. Thereby, different magnitudes of braking force can be applied to one side of the movable part at different timings, and various braking effects can be obtained.

Further, the micro electro mechanical modulation element of the present invention is characterized in that when the movable part reaches the final position of the displacement in the specific direction, it is stopped in contact with the stop member.

  In this micro electromechanical modulation element, when the movable part reaches the final position, it comes into contact with the stop member (landing site) and is stopped. That is, the micro electro mechanical modulation element is operated as a so-called contact type. In this case, the movable portion receives a reaction force from the stop member immediately after landing, but is braked and forcibly controlled by the physical action force.

A micro electro mechanical modulation element array according to the present invention is characterized in that one of the above micro electro mechanical modulation elements is arranged one-dimensionally or two-dimensionally.

  In this microelectromechanical modulation element array, microelectromechanical modulation elements that are capable of high-speed switching operation are arrayed, and it is possible to reduce the time to calm down the vibration. It becomes possible.

In the micro electro mechanical modulation element array of the present invention, each of the micro electro mechanical modulation elements includes a drive circuit including a memory circuit, and the first drive source of each of the micro electro mechanical modulation elements. , And the second drive source is composed of a pair of electrodes respectively provided on the movable portion and a fixed portion facing the movable portion, and any one of the pair of electrodes is It is a signal electrode to which an element displacement signal from the drive circuit is input, and the other electrode is a common electrode.

  In this micro electro mechanical modulation element array, a memory circuit is provided, so that an element displacement signal can be written to the memory circuit in advance. A plurality of micro electro mechanical modulation elements are applied by applying an element displacement signal previously written in the memory circuit to the signal electrode at the same time as applying a constant voltage common to the common electrode to the common electrode. Can be driven at high speed.

Further, the micro electro mechanical modulation element array of the present invention is characterized in that a control section for modulating and driving each of the movable sections is provided.

  In this micro electromechanical modulation element array, the movable part is driven and controlled by the control part, so that the absolute value of the voltage between the movable electrode and the fixed electrode before the movable part reaches the final displacement position. Is decreased, increased, or increased and decreased, and vibrations and overshoots caused by a collision caused by the movable part reaching the final displacement position can be suppressed.

The image forming apparatus according to the present invention includes a light source, any one of the micro electro mechanical modulation element arrays, and a plurality of micro electro mechanical modulation elements included in the micro electro mechanical modulation element array. An illumination optical system that irradiates the element, and a projection optical system that projects light emitted from the microelectromechanical modulator array modulated by each of the plurality of microelectromechanical modulator elements onto an image forming surface. It is characterized by having.

  In this image forming apparatus, the micro electro mechanical modulation element array according to any one of claims 10 to 12 is provided in a main part of the configuration, so that vibration can be actively reduced. The driving cycle is shortened. As a result, high-speed photosensitive material exposure and display of a projector having a higher number of pixels are possible. In addition, in an image forming apparatus (exposure apparatus) in which gradation control is performed by turning on and off exposure light, the on / off time can be shortened, so that higher gradation can be realized.

  According to the microelectromechanical modulation element of the present invention, there are a plurality of drive sources that apply a physical acting force to the movable part, and when the movable part is driven to be displaced in the first direction by the drive source, the movable part is While the transition to the direction 1 is performed, a physical acting force that suppresses the vibration of the movable part is applied to the movable part in a second direction different from the first direction by the drive source. It is possible to actively reduce the vibration at the time of contact of the movable part by applying a physical attractive force in the reverse direction. As a result, the switching operation in the micro electromechanical modulation element can be speeded up.

  According to the microelectromechanical modulation element array according to the present invention, vibration after the movable part reaches the final displacement position is suppressed. Accordingly, it is possible to eliminate or drastically shorten the vibration soothing time, and it is possible to write the address voltage without waiting for the vibration to settle. As a result, the driving cycle can be shortened and the switching operation can be speeded up.

  According to the image forming apparatus of the present invention, the light source, the microelectromechanical modulation element array according to any one of claims 10 to 12, and the light from the light source into the microelectromechanical modulation element array. Since the illumination optical system for irradiation and the projection optical system for projecting the light emitted from the micro electro mechanical modulation element array onto the image forming surface are provided, the switching operation can be shortened as compared with the conventional apparatus. As a result, it is possible to perform high-speed photosensitive material exposure and display of a projector with higher pixels.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of a microelectromechanical modulation element, a microelectromechanical modulation element array, and an image forming apparatus according to the invention will be described with reference to the drawings.
FIG. 1 is a conceptual diagram showing a first embodiment of a micro electro mechanical modulation element according to the present invention, and FIG. 2 shows the vibration damping process of the micro electro mechanical modulation element shown in FIG. FIG. 3 is an explanatory diagram showing the behavior of the movable part to which the pulse waveform is applied.
A microelectromechanical modulation element (hereinafter also simply referred to as a “modulation element”) 100 according to the present embodiment is arranged in parallel with a substrate 21 and a substrate 21 via a gap 23 as basic components. A small piece-like movable portion 27, hinges 29 and 29 extending from both edges of the movable portion 27, and spacers 31 and 31 that support the movable portion 27 on the substrate 21 through the hinges 29 and 29 are provided. . With such a configuration, the movable portion 27 can be rotationally displaced by twisting of the hinges 29 and 29.

  In addition, the modulation element according to the present invention can also modulate sound waves, fluids, and heat rays by appropriately selecting the material of the movable 27. When the modulation element 100 is used as an optical element, the movable part 27 serves as a light reflector (mirror part) to modulate light by a deflecting action. This modulation method uses the structure and material of the movable part 27 as appropriate. By selecting, modulation by a transmission type, a shutter method, an interference method, a diffraction method, or a total reflection method can be made possible.

  In the present embodiment, the movable portion 27 is stopped in contact with a stop member (not shown) when reaching the final position of displacement in a specific direction. That is, a contact-type modulation element is configured. Therefore, when the movable part 27 reaches the final position, it comes into contact with a stop member (so-called landing site) and is stopped.

  On the upper surface of the substrate 21, the first address electrode 35 a and the second address electrode 35 b are provided on both sides with the hinges 29, 29 as the center. The movable part 27 is also provided with a movable electrode (not shown) in a part thereof. The modulation element 100 swings and displaces the movable portion 27 by applying a voltage to the first address electrode 35a, the second address electrode 35b, and the movable portion 27 as a basic operation. That is, if the movable part 27 is a mirror part, the reflection direction of light is deflected.

  In the modulation element 100, when a potential difference is applied to the first address electrode 35a and the second address electrode 35b with respect to the movable portion 27, electrostatic force is generated between the respective electrodes and the movable portion 27, and the hinges 29, 29 are generated. Rotational torque works around The electrostatic force generated at this time depends on the dielectric constant in vacuum, the area of the movable part 27, the applied voltage, and the distance between the movable part 27 and the address electrode.

  Therefore, when the dielectric constant in vacuum, the area of the movable portion 27, the distance between the movable portion 27 and the address electrode, and the elastic coefficients of the hinges 29 and 29 are constant, the movable portion 27 controls the potential of each electrode. Thus, it can be rotated and displaced to the left and right. For example, when Va> Vb, the electrostatic force generated at the first address electrode 35a and the movable portion 27 is larger than the electrostatic force generated at the second address electrode 35b and the movable portion 27, and the movable portion 27 tilts to the left. On the other hand, when Va <Vb, the electrostatic force generated at the second address electrode 35b and the movable portion 27 is larger than the electrostatic force generated at the first address electrode 35a and the movable portion 27, and the movable portion 27 is on the right side. Lean on.

  As described above, the movable electrode of the movable portion 27, the first address electrode 35a, and the second address electrode 35b serve as a drive source for rotationally displacing the movable portion 27. Such a physical acting force applied from the drive source to the movable portion 27 becomes an electrostatic force, whereby high-speed rotational displacement is possible.

  The physical acting force that acts on the movable portion 27 may be a physical acting force other than the electrostatic force. As other physical acting force, for example, an effect by a piezoelectric body and an electromagnetic force can be cited. In this case, a piezoelectric actuator using a piezoelectric element or an electromagnetic actuator using a magnet / coil is employed as a drive source.

  The modulation element 100 includes a movable portion 27 that is displaced in both directions, and the movable portion 27 has a modulation function. The movable portion 27 is rotationally displaced by a plurality of drive sources (movable electrodes of the movable portion 27, the first address electrode 35a, the second address electrode 35b) that apply a physical acting force. Here, when the movable element 27 is driven to be displaced in the left direction (first direction) in FIG. 1 by the drive source, the modulation element 100 is driven while the movable part 27 is shifted in the first direction. Thus, a physical acting force that suppresses vibration of the movable portion 27 is applied to the movable portion 27 in a second direction different from the first direction.

  As shown in FIG. 2A, first, the drive voltage Va is applied to the first address electrode 35a in the left rotation direction. Next, as shown in FIG. 2B, the vibration suppression voltage Vb is applied to the second address electrode 35b immediately before the left end of the movable portion 27 contacts the stop member. As a result, as shown in FIG. 2C, an electrostatic force is generated in the movable portion 27 and the second address electrode 35b by the vibration suppression voltage Vb, and this electrostatic force moves the right end of the movable portion 27 toward the substrate 21. Draw. This electrostatic attraction force acts as a vibration absorption effect, and the movable portion 27 comes to rest simultaneously with the contact with the stop member.

  As described above, when the movable portion 27 reaches the final position of the displacement in the specific direction, the speed at that moment becomes substantially zero, so that the conventional movable portion has reached the final displacement position at a high speed. Vibration due to a collision will not occur.

  Further, when the movable portion 27 reaches the final position, the movable portion 27 comes into contact with the stop member (landing site) and receives a reaction force from the stop member immediately after landing, but is braked by the electrostatic attraction force and forcedly Damped. And since the physical action force which acquires a vibration absorption effect is an electrostatic force, a high-speed vibration suppression force is obtained.

  Furthermore, physical action force is applied to a plurality of action points of the movable part 27 (left and right of the movable part 27 in the present embodiment), so that, for example, in the oscillating type movable part 27 whose center is the rotation center, Physical action force can be applied to both sides of the center of rotation, and different magnitudes of braking force can be applied to each action point at different timings, so that various braking effects can be obtained. .

  The vibration suppression voltage Vb for generating the electrostatic attraction force, that is, the voltage applied to the movable portion 27 and the second address electrode 35b is expressed by the vertical axis shown in FIG. A pulse waveform with the axis as time can be obtained. In this example, one pulse waveform p1 in the reverse direction is applied immediately before the movable portion 27 contacts the stop member. Hereinafter, the pulse wave applied to the movable part 27 and the second address electrode 35b as the vibration suppression voltage Vb is applied to the "reverse pulse wave", and the drive voltage Va is applied to the movable part 27 and the first address electrode 35a. This pulse wave is referred to as “forward pulse wave”.

  By setting the vibration suppression voltage Vb to such a pulse waveform, an electrostatic attractive force is generated in a voltage range specified by the pulse waveform, and various braking effects can be obtained. Here, the pulse waveform includes a rectangular wave, a sine wave, a cosine wave, a sawtooth wave, a triangular wave, and a synthesized wave thereof.

  In this modulation element 100, during the transition before the movable portion 27 reaches the final displacement position, a physical attractive force acts in the direction opposite to the transition direction, and the movable portion 27 immediately before reaching the final displacement position. The speed is reduced. As a result, vibration due to a collision that occurs when the movable portion reaches the final displacement position at a high speed and overshoot when reaching the final displacement position by non-contact driving are suppressed. That is, vibration at the time of contact of the movable portion 27 can be actively reduced.

Next, modifications of various pulse waveforms applied to the vibration suppression voltage Vb and the drive voltage Va in order to generate an electrostatic attraction force that obtains a vibration absorption effect will be described.
FIG. 4 is an explanatory view showing Modification 1 in which two rectangular pulse waveforms are applied.
In the following embodiments and modifications, the same members / parts are denoted by the same reference numerals, and redundant description will be omitted.
In this modification, a plurality of pulse waves P <b> 2 and P <b> 3 in opposite directions are applied immediately before the movable portion 27 contacts. Although two pulse waves P2 and P3 are illustrated in the figure, the number of pulse waveforms may be two or more.
According to this modification, the electrostatic attractive force, which is a physical acting force, is applied at different magnitudes and at different timings, and various braking effects can be obtained.

FIG. 5 is an explanatory view showing Modification 2 in which a triangular pulse waveform is applied.
In this modification, the pulse wave P4 is a triangular wave. As described above, the pulse wave may be a triangular wave, a sine wave, or another waveform.
According to this modification, an electrostatic attraction force, which is a physical acting force, is applied at a steep timing that cannot be obtained with a rectangular wave.

FIG. 6 is an explanatory diagram showing a third modification in which two triangular pulse waveforms are applied.
In this modification, a plurality of triangular pulse waves P <b> 5 and P <b> 6 in opposite directions are applied immediately before the movable portion 27 contacts. In the figure, two triangular pulse waves P5 and P6 are illustrated, but two or more triangular pulse waveforms may be provided.
According to this modification, a steep electrostatic attraction force is applied at different magnitudes and at different timings.

FIG. 7 is an explanatory diagram showing a fourth modification in which a pulse waveform is applied to the drive voltage Va.
In this modification, after the pulse wave P2 in the reverse direction is applied immediately before the movable portion 27 comes into contact with the stop member, the movable portion 27 moves away from the stop member by a reaction force after coming into contact with the stop member. A forward pulse wave P7 is applied to the drive voltage Va. That is, after the movable portion 27 is driven to be displaced in the left rotation direction (first direction), the drive source (first address electrode 35a) is moved while the movable portion 27 is shifted in the right rotation direction (second direction). The physical acting force is applied to the movable part 27 in the first direction by the movable part 27).
According to this modification, after the movable portion 27 is driven to move in the first direction and reaches the final position of the displacement, the movable portion 27 is further moved in the second direction by the reaction force or the elastic force caused by contacting the stop member. During the transition, the physical acting force in the first direction is applied to the movable portion 27, so that the movement of the movable portion 27 that is going to move away from the final position of the displacement is actively braked.

FIG. 8 is an explanatory view showing Modification 5 in which a pulse waveform is applied to the braking electrode after a pulse waveform is applied to the drive voltage Va.
In this modification, the pulse wave P2 in the reverse direction and the pulse wave P7 in the forward direction are applied in the reverse order to the modification example shown in FIG. That is, the forward pulse wave P7 is applied immediately after the movable part 27 comes into contact and moves away, and the reverse pulse wave P2 is applied immediately before the movable part 27 comes into contact with the stop member again.
According to this modification, after the movable portion 27 reaches the final position of displacement, the first direction is changed while the transition is made in the second direction by the reaction force or the elastic force caused by contacting the stop member. Is applied to the movable portion 27, and the movement of the movable portion 27 that attempts to move away from the final position of the displacement is actively braked. Further, immediately before the movable part 27 that cannot be stopped by this braking tries to contact the stop member again, the pulse wave P <b> 2 in the reverse direction is applied and the movable part 27 is reliably stopped.

FIG. 9 is an explanatory diagram showing a sixth modification in which the drive voltage Va is reduced at predetermined intervals.
In this modified example, the pulse wave P8 in the reverse direction is applied immediately before the movable portion 27 contacts the stop member, and at the same time, the pulse wave P9 in the forward direction with a reduced voltage is applied.
According to this modification, immediately before the movable part 27 comes into contact with the stop member, braking is performed by the pulse wave P8 in the reverse direction, and the driving voltage Va at that time is canceled by the pulse wave P9, thereby moving the movable part 27. The portion 27 is braked with a greater force. In this case, the pulse wave P9 is lowered to 0V in the drawing, but the reduced voltage of the forward pulse wave P9 may not be 0V.

FIG. 10 is an explanatory diagram showing a modified example 7 in which a plurality of driving voltages Va are reduced at predetermined intervals.
In this modification, a plurality of reverse-direction pulse waves P2 and P3 are applied, and at the same time, forward-direction pulse waves P9 and P10 with a reduced voltage are applied.
According to this modification, the operation of the modification shown in FIG. 9 is repeated, and the movable portion 27 is braked more reliably.

FIG. 11 is an explanatory view showing a modified example 8 in which a constant voltage is applied after the pulse waveform is applied.
In this modification, the pulse wave P1 in the reverse direction is applied immediately before the movable portion 27 contacts the stop member, but thereafter, a constant voltage Vb1 is continuously applied. In other words, the pulse wave in the reverse direction does not necessarily have to be 0 V at the normal time.
According to this modification, the movable portion 27 is biased in the reverse direction after contacting. Therefore, the movable part 27 can be driven with a small voltage difference.

FIG. 12 is an explanatory view showing Modification 9 in which a constant voltage is applied after applying a plurality of pulse waveforms.
In this modification, a plurality of pulse waves P2 and P3 in opposite directions are applied immediately before the contact of the movable portion 27, and the constant voltage Vb1 is continuously applied during and after that.
According to this modification, a reliable vibration absorption effect can be obtained, and the movable portion 27 can be driven with a small voltage difference.

FIG. 13 is an explanatory diagram showing a modified example 10 in which a constant voltage is applied before a pulse waveform is applied.
In this modification, a pulse wave P1 in the reverse direction is applied to a straight line where the movable portion 27 contacts the stop member, and then a constant voltage Vb1 is continuously applied, but a pulse wave P1 in the reverse direction is applied. Even before, the constant voltage Vb1 is applied as the vibration suppression voltage Vb.
According to this modification, the movable part 27 is always biased in the reverse direction, and the movable part 27 can be driven with a small voltage difference. The vibration of the movable part 27 is always a balance between the electrostatic force in the forward direction and the reverse direction, and in the case of the contact type, it is pulled in (retracted) in the reverse direction of the range where the movable part 27 maintains the contact state. If the voltage is constant, there is no problem even if it is always applied.

  Therefore, according to the microelectromechanical modulation element described above, there are a plurality of drive sources that apply a physical acting force to the movable portion 27, and when the movable portion 27 is driven to be displaced in the first direction by the drive source, the movable portion Since the physical acting force is applied to the movable part 27 in the second direction different from the first direction by the drive source while the 27 is transiting in the first direction, the direction opposite to the transition direction of the movable part 27 is applied. Thus, it is possible to actively reduce the vibration at the time of contact of the movable portion 27 by applying a physical attractive force. As a result, the switching operation in the modulation element 100 can be speeded up.

Next, a second embodiment of the microelectromechanical modulation element according to the present invention will be described.
FIG. 14 is a conceptual diagram showing a second embodiment of a micro electro mechanical modulation device according to the present invention.
The modulation element 200 according to the present embodiment is configured such that two or more physical acting forces can be set for each transition direction of the movable portion 27. That is, the main first address electrode 35a1, the sub first address electrode 35a2, the main second address electrode 35b1, and the sub second address electrode 35b2 are arranged on the left and right sides of the hinges 29 and 29 on the substrate 21 in the center. Is provided. The drive voltage Va1 is applied to the main first address electrode 35a1 and the movable portion 27, and the drive voltage Va2 is applied to the sub first address electrode 35a2 and the movable portion 27. Further, the vibration suppression voltage Vb1 is applied to the main second address electrode 35b1 and the movable portion 27, and the vibration suppression voltage Vb2 is applied to the sub second address electrode 35b2 and the movable portion 27.

  According to this modulation element 200, in the swingable movable portion 27 whose center is the rotation center, two or more physical acting forces are applied to each side of both sides sandwiching the rotation center. As a result, braking forces of different magnitudes can be applied to one side of the movable portion 27 at different timings, and various braking effects can be obtained.

Next, a third embodiment of the micro electro mechanical modulation device according to the present invention will be described.
FIG. 15 is a conceptual diagram showing a third embodiment of a micro electro mechanical modulation device according to the present invention.
In the modulation element 300 according to the present embodiment, one end of the movable portion 41 is supported and fixed to the substrate 21 via hinges 29 and 29 and spacers 31 and 31. That is, the movable part 41 is configured in a cantilever shape with the other end being a free end. A first address electrode 35a is provided on the substrate 21 so as to face the free end of the movable portion 41, and is formed on a counter substrate (not shown) on the opposite side of the first address electrode 35a across the movable portion 41. A second address electrode 35b is provided.

  Also in the modulation element 300 having such a configuration, the drive voltage Va is applied to the first address electrode 35a and the movable portion 41, and the vibration suppression voltage Vb is applied to the second address electrode 35b and the movable portion 41, thereby being movable. During the transition before the portion 27 reaches the final displacement position (in this case, the stop member on the first address electrode 35a side), an electrostatic attraction force is applied in the direction opposite to the transition direction, so that the movable portion 27 The speed immediately before reaching the final displacement position can be reduced.

  Thereby, it is possible to suppress the vibration caused by the collision that has occurred when the movable portion 27 reaches the final displacement position at a high speed. That is, vibration at the time of contact of the movable portion 27 can be actively reduced.

Next, a fourth embodiment of the microelectromechanical modulation element according to the present invention will be described.
FIG. 16 is a conceptual diagram showing a fourth embodiment of a micro electro mechanical modulation element according to the present invention.
The modulation element 400 according to the present embodiment is a so-called parallel plate type element, and both ends of a plate-like movable portion 43 having conductivity and flexibility are formed on the insulating film 45 formed on the substrate 21 with a predetermined amount. The gap 47 is fixed. A first address electrode 35 a is disposed below the movable portion 43 of the substrate 21 via an insulating film 45, and a second address electrode is disposed above the movable portion 43 via an insulating film 49. 35b is disposed. In other words, the movable portion 43 is configured as a doubly supported beam in which both ends are supported between the first address electrode 35a and the second address electrode 35b.

  Also in such a parallel plate type modulation element 400, the drive voltage Va is applied to the first address electrode 35 a and the movable portion 41, and the vibration suppression voltage Vb is applied to the second address electrode 35 b and the movable portion 41. During the transition before the movable portion 43 reaches the final displacement position (in this case, the stop member on the first address electrode 35a side), an electrostatic attraction force is applied in the direction opposite to the transition direction, and the movable portion 43 The speed immediately before 43 reaches the final displacement position can be reduced.

  Further, the direction, structure, and driving of the elements are not limited to the configuration of the modulation element in each of the above embodiments, and the present invention can be applied to all elements that are driven bidirectionally. .

Next, a result of simulation performed on the modulation element having the configuration of the first embodiment will be described.
FIG. 17 is an explanatory diagram showing the operation of a microelectromechanical modulation element having a configuration equivalent to that of the first embodiment confirmed by simulation.
With respect to the rotary hinge type micromachine element as shown in FIG. 1, the vibration after the transition of the moving part was analyzed by simulation, where Va is the forward potential difference and Vb is the reverse potential difference.
As a result, the movable portion when the potential difference of Va = V1 is applied after time t1 is greatly oscillated, but the potential difference of Va = V1 is applied after time t1, and then Vb is applied between times t2 and t3. It was found that when a potential difference of = V2 was applied, vibration of the movable part was suppressed.

Next, the result of manufacturing a modulation element having the configuration of the first embodiment and actually operating it will be described.
FIG. 18 is an explanatory view of actually fabricating a micro-electromechanical modulation element having a configuration equivalent to that of the first embodiment and confirming its operation.
With respect to the rotating hinge micromachine element as shown in FIG. 1, the forward potential difference is Va and the reverse potential difference is Vb, and the vibration after the moving part transition by the actual element was analyzed.
As a result, as shown in FIG. 18 (a), the movable part vibrates greatly when a potential difference of Va = V1 is applied after time t1, but as shown in FIG. 18 (b), Va is reached after time t1. = V1 potential difference is applied, and then when the potential difference of Vb = V2 is applied between time t2 and t3, it can be seen that the vibration of the movable part is suppressed (the input waveform has a delay) Due to the performance limit of the function generator).

FIG. 19 is an explanatory diagram showing the behavior of the movable part when the present invention is applied to a non-contact type microelectromechanical modulation element.
In each of the above-described embodiments and modifications, the case where the modulation element is a contact type has been described as an example. However, even when the present invention is applied to a non-contact type modulation element, the same operations and effects as described above are achieved. It is what you play.

  That is, when the movable part 27 is driven to be displaced in the first direction by the drive source, while the movable part 27 is transitioning to the first direction, the drive source is different from the first direction with respect to the movable part 27. By applying a physical acting force in the direction 2 by the pulse wave P1, a physical attractive force can be exerted in a direction opposite to the transition direction of the movable portion 27, and the overshoot of the movable portion 27 can be actively reduced. As a result, the switching operation in the non-contact drive modulation element can be speeded up.

Each of the modulation elements 100, 200, and 300 disclosed in the above embodiments is arranged in a one-dimensional or two-dimensional manner to form a micro electromechanical modulation element array (hereinafter simply referred to as “modulation element array”). Can be configured.
In such a modulation element array, the modulation elements 100, 200, and 300 capable of high-speed switching operation are arrayed, and it is possible to shorten the time for the vibration to calm down and to write address voltage faster than before. It becomes.
Therefore, the vibration after the movable part reaches the final displacement position is suppressed, and it becomes possible to eliminate the vibration soothing time or to greatly reduce it, and to write the address voltage without having to wait for the vibration to settle. be able to. As a result, the switching operation can be speeded up and the driving cycle can be shortened.

Further, as shown in FIG. 20 as an example of the drive circuit of the modulation element array 100 of FIG. 1, the modulation element array preferably has a drive circuit including a memory circuit. By providing such a memory circuit, an element displacement signal can be written to the memory circuit in advance. That is, an element displacement signal is written in advance in the memory circuit. When switching the modulation element, the drive voltage of the present invention is modulated at a desired timing by the element displacement signal stored in the memory circuit of each modulation element and the drive voltage control circuit that controls the voltage applied to the modulation element. Output to the signal electrode. At this time, a desired voltage is also output to the common electrode (movable part).
As described above, when the element is driven using the memory circuit, each of the plurality of modulation elements can be easily operated with an arbitrary driving pattern, and higher-speed active driving is possible. Here, the configuration of the light modulation element array 100 of FIG. 1 is shown, but the present invention is not limited to this, and modulation elements having other configurations may be used.

The modulation element array is preferably provided with a control unit that modulates and drives each movable unit.
In the modulation element array provided with such a control unit, the movable unit is driven and controlled by the control unit, so that the gap between the movable electrode and the fixed electrode is reduced before the movable unit reaches the final displacement position. The absolute value of the voltage is decreased, increased, or increased and decreased, and vibrations and overshoots caused by a collision caused by the movable part reaching the final displacement position can be suppressed.

The modulation element array having the above-described configuration includes a light source, an illumination optical system that irradiates light from the light source onto the modulation element array, and a projection optical system that projects light emitted from the modulation element array onto an image forming surface. Thus, an image forming apparatus can be configured.
In the image forming apparatus provided with the modulation element array, vibration can be actively reduced, and the driving cycle is shortened as compared with the conventional apparatus. As a result, high-speed photosensitive material exposure and display of a projector having a higher number of pixels are possible. In addition, in an image forming apparatus (exposure apparatus) in which gradation control is performed by turning on and off exposure light, the on / off time can be shortened, so that higher gradation can be realized.
Note that the timing and waveform of the voltage drive to each electrode described above are not limited to this, and can be appropriately changed as long as they do not depart from the gist of the present invention.

It is a conceptual diagram showing 1st Embodiment of the micro electro mechanical modulation element which concerns on this invention. FIG. 3 is an operation explanatory diagram illustrating a vibration damping process of the micro electro mechanical modulation device illustrated in FIG. 1 by (a), (b), and (c). It is explanatory drawing showing the behavior of the movable part to which the pulse waveform was applied. It is explanatory drawing showing the modification 1 to which two rectangular pulse waveforms are applied. It is explanatory drawing showing the modification 2 to which a triangular pulse waveform is applied. It is explanatory drawing showing the modification 3 to which two triangular pulse waveforms are applied. It is explanatory drawing showing the modification 4 by which a pulse waveform is applied to the drive voltage Va. It is explanatory drawing showing the modification 5 by which a pulse waveform is applied to a braking electrode after a pulse waveform is applied to the drive voltage Va. It is explanatory drawing showing the modification 6 by which the drive voltage Va is reduced by a predetermined space | interval. It is explanatory drawing showing the modification 7 by which the drive voltage Va is reduced by two or more by predetermined space | interval. It is explanatory drawing showing the modification 8 to which a fixed voltage is applied after a pulse waveform application. It is explanatory drawing showing the modification 9 to which a fixed voltage is applied after several pulse waveform application. It is explanatory drawing showing the modification 10 to which a fixed voltage is applied before a pulse waveform is applied. It is a conceptual diagram showing 2nd Embodiment of the micro electro mechanical modulation element which concerns on this invention. It is a conceptual diagram showing 3rd Embodiment of the micro electro mechanical modulation element which concerns on this invention. It is a conceptual diagram showing 4th Embodiment of the micro electro mechanical modulation element which concerns on this invention. It is explanatory drawing which confirmed the operation | movement confirmation by the simulation of the micro electro mechanical modulation | alteration element which has the structure equivalent to 1st Embodiment. It is explanatory drawing which actually manufactured the micro electro mechanical modulation element which has the structure equivalent to 1st Embodiment, and confirmed operation | movement. It is explanatory drawing showing the behavior of the movable part at the time of applying this invention to a non-contact-type microelectromechanical modulation element. It is explanatory drawing which shows the structure with which each of the modulation | alteration element had the drive circuit containing a memory circuit. It is explanatory drawing showing the vibration of the movable part which arises in the conventional micro electromechanical modulation element. It is explanatory drawing of the braking pulse applied in the conventional micro mechanical lattice apparatus. It is explanatory drawing of the signal voltage waveform applied in the conventional optical path switching apparatus. It is explanatory drawing of the control signal applied in the control method of the conventional micromachine element.

Explanation of symbols

27, 41 ... movable part 35a ... first address electrode 35b ... second address electrode 100, 200, 300, 400 ... minute electromechanical modulation elements P1-P10 ... pulse waveform

Claims (12)

A microelectromechanical modulation element that includes a movable part that is supported so as to be elastically displaceable and that is displaced in both directions of the first direction and the second direction, the movable part having a modulation function;
A first driving source that applies a physical acting force to the movable portion to displace the movable portion in the first direction, and a physical acting force to displace the movable portion in the second direction to the movable portion. A second drive source to be added,
While applying the physical acting force to the movable part by the first drive source and displacing the movable part in the first direction toward the final position of the displacement in the first direction, A micro electromechanical modulation element that applies the physical action force to the movable part by the second driving source to brake the movable part.   2. The micro electro mechanical system according to claim 1, wherein when the movable part reaches a final position of displacement in the first direction or the second direction, the speed of the movable part becomes substantially zero. Modulation element.   The physical acting force applied to the movable part by the first driving source and the physical acting force applied to the movable part by the second driving source are electrostatic forces. The microelectromechanical modulation element according to claim 1 or 2.   The physical acting force applied to the movable part by the first drive source and the physical acting force applied to the movable part by the second drive source are intensity on the vertical axis and time on the horizontal axis. 4. The micro electro mechanical modulation device according to claim 1, wherein the micro electro mechanical modulation device is applied like a pulse waveform.   The physical acting force applied to the movable part by the first drive source and the physical acting force applied to the movable part by the second drive source are generated by a plurality of pulse waveforms. The micro electro mechanical modulation device according to claim 4. The first driving source includes two or more driving units that independently generate a physical acting force that displaces the movable unit in the first direction;
The said 2nd drive source contains two or more drive parts which produce | generate the physical action force which displaces the said movable part to the said 2nd direction independently of each other. 6. The microelectromechanical modulation element according to any one of 5 above. Said movable part, upon reaching the final position of displacement of the first direction or the second direction, any one of claims 1 to 6, characterized in that the stop in contact with the stop member 2. A microelectromechanical modulation element according to item 1.   After the movable part is driven to move in the first direction and brought into contact with the stop member, the movable part is displaced in the second direction by a reaction force due to contact with the stop member. 8. The micro electro mechanical modulation element according to claim 7, wherein a physical acting force is applied to the movable part in the first direction by the first driving source.   9. A micro electro mechanical modulator array, wherein the micro electro mechanical modulator elements according to claim 1 are arranged one-dimensionally or two-dimensionally. Each of the micro electro mechanical modulation elements has a drive circuit including a memory circuit,
Each of the first drive source and the second drive source of each of the micro electro mechanical modulation elements includes a pair of electrodes provided on the movable portion and a fixed portion facing the movable portion, respectively. Has been
10. The microelectromechanical machine according to claim 9, wherein one of the pair of electrodes is a signal electrode to which an element displacement signal is input from the drive circuit, and the other electrode is a common electrode. Type modulation element array.   11. The micro electro mechanical modulation element array according to claim 9, further comprising a control unit that modulates and drives each of the movable units. A light source;
A microelectromechanical modulation element array according to any one of claims 9 to 11,
An illumination optical system for irradiating light from the light source to a plurality of micro electro mechanical modulation elements included in the micro electro mechanical modulation element array;
A projection optical system for projecting light, which is modulated by each of the plurality of microelectromechanical modulation elements and emitted from the microelectromechanical modulation element array, onto an image forming surface; apparatus.

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