JP4335114B2 - Micromirror device - Google Patents

Description

  The present invention relates to a micromirror device that includes a piezoelectric actuator array as a drive mechanism and can freely change the angle of a micromirror by a displacement caused by a piezoelectric element of the piezoelectric actuator array.

  Recently, construction of an optical communication network system that does not perform photoelectric conversion has further progressed, and it is considered that network systems using light instead of electrical signals will become mainstream in the future. Under these circumstances, in order to cope with an increase in the capacity of optical communication networks, there is an expectation for an optical switch that can switch the path of an optical signal as it is, and it is suitable for use and application in the optical switch. Development of a new micromirror device is urgent.

  The micromirror device is a device that can precisely control the angles of a plurality of micromirrors arranged one-dimensionally or two-dimensionally in two axial directions. By controlling the angle of the micromirror, the reflection direction of the light beam incident on the micromirror can be switched and used as the main component of the optical switch. Such a micromirror device is generally manufactured by a MEMS (Micro Electro Mechanical System) technology using a silicon process, and uses an electrostatic actuator as a driving mechanism.

An example of a conventional micromirror device using an electrostatic actuator as a drive mechanism is shown in FIGS. 8 (a) and 8 (b). FIG. 8A is a plan view, and FIG. 8B is a diagram showing an AA ′ cross section in FIG. The illustrated micromirror device 80 is a device in which a micromirror 81 is attached to a mirror mounting portion 84 supported by a torsion bar 82 so as to be easily movable. The micromirror device 80 is a device capable of controlling the angle of the micromirror 81 by energizing the electrode 83 to apply an electrostatic force to the mirror mounting portion 84 to tilt the mirror mounting portion 84. Note that Patent Documents 1 to 3 are cited as prior documents relating to a micromirror or an optical switch including the micromirror.
US Pat. No. 5,960,132 US Pat. No. 6,072,924 JP-A-8-320441 US Patent Application Publication No. 2004/0070315

  However, since the micromirror device 80 shown in FIG. 8A and FIG. 8B uses an electrostatic force, there is a condition that the driving force is small and the micromirror 81 must be made light and thin. there were. As a result, there is a problem that the rigidity of the micromirror 81 is lowered and easily deformed, and the light beam is easily distorted after reflection. Further, the operation of changing the angle of the micromirror 81 is slow, and it is difficult to switch the optical signal at high speed.

  The present invention has been made in view of such conventional problems, and an object of the present invention is to provide a micromirror device that overcomes the disadvantages of conventional micromirror devices using electrostatic force. It is in. As a result of repeated research, a piezoelectric actuator (array) capable of precise positioning control with a large driving force that can drive a rigid (ie, heavy) micromirror at high speed is used as the driving mechanism. A micromirror device equipped with a mechanism to convert the expansion and contraction displacement caused by the piezoelectric element into a rotational displacement in the biaxial direction of the micromirror can suppress the distortion of the light beam and switch the optical signal faster. As a result, the present invention has been completed.

  That is, first, according to the present invention, a micromirror and a piezoelectric actuator array in which a plurality of piezoelectric elements that express expansion and contraction in the normal direction of the mirror surface of the micromirror are arranged, the piezoelectric actuator array is provided. A micromirror device disposed on the back surface of a micromirror, wherein an elastic member is provided between the micromirror and the piezoelectric actuator array to connect the tops of a plurality of piezoelectric elements constituting the piezoelectric actuator array. And the elastic member are connected to each other via a narrow support portion provided at the connecting portion of the elastic member, and the expansion / contraction displacement of the piezoelectric element constituting the piezoelectric actuator array is microscopic via the elastic member. A micromirror device is provided that translates into rotational displacement in the biaxial direction of the mirror.

  In the micromirror device of the present invention, the number of micromirrors is not limited and may be one or more, but a plurality of piezoelectric elements are combined with one micromirror. In order to rotate one micromirror in two axial directions, at least three or more piezoelectric elements (actuators), or two piezoelectric elements and one fixed portion (may be a non-moving piezoelectric element) may be combined. . By elastically displacing at least one or more piezoelectric elements with this combination, the elastic member that connects the tops of the piezoelectric elements bends, and the angle of the micromirror can be made variable through the deformation.

  The narrow support portion is a portion that supports the micromirror when viewed from the elastic member side, and the narrowness is not particularly limited in size, but at least a portion where each of the micromirror and the elastic member joins the narrow support portion. As long as the displacement that the piezoelectric element of the piezoelectric actuator array has sufficient strength and can be transmitted to the micromirror with good reproducibility, the area of the portion where the narrow support portion and the elastic member are joined Means to a smaller extent. This is because if the micromirror and the elastic member are connected by such a narrow support portion, the deformation of the elastic member caused by the displacement expressed by the piezoelectric element is further amplified and transmitted to the micromirror. Although a narrow support part is not limited, For example, the thing of a thin cylindrical body shape is employable.

  Further, the narrow support portion is a portion where the connection between the micromirror and the elastic member is interposed, and may be a protrusion integrated on the elastic member side or a protrusion integrated on the micromirror side. The member may be a member that is molded independently.

  Further, the position where the narrow support portion is provided is not limited as long as it is a portion of the elastic member that connects the top portions of the plurality of piezoelectric elements, but a more preferable position is the center between the top portions of the plurality of piezoelectric elements. . This is because the displacement generated by the plurality of piezoelectric elements is uniformly transmitted to the micromirror, so that the angle can be easily controlled.

  Elasticity of an elastic member means elasticity against plasticity. An elastic member is a member having a property of deforming when an external force is applied to an object and returning to its original shape when the force is removed. This corresponds to the member.

  In the micromirror device of the present invention, the piezoelectric actuator array is formed by a plurality of piezoelectric elements having a columnar shape, arranged in a matrix on one surface of the ceramic substrate, and integrally fired with the ceramic substrate. The elastic member is preferably a sheet-like member that exhibits a lattice pattern.

  As a piezoelectric actuator array using the displacement of the piezoelectric lateral effect as described above, for example, a low dust generation matrix type piezoelectric (/ electrostrictive) device described in Patent Document 4 disclosed by the present applicant is provided. Those that exhibit a displacement due to the piezoelectric lateral effect are suitable. The displacement of the piezoelectric lateral effect refers to a displacement when the piezoelectric element is deformed so as to expand and contract in a direction perpendicular to the electric field in the same direction as the polarization direction.

  The piezoelectric elements constituting the piezoelectric actuator array are displacement elements in which a piezoelectric body is sandwiched between at least a pair of electrodes, and are not limited, but each piezoelectric element includes an even number of layered piezoelectric bodies, each of which It is preferable that the layered common electrode and the layered individual electrode are alternately sandwiched on the surface of the substrate, and the layered common electrode is preferably laminated as the outermost layer, and the number of layered piezoelectric bodies is four. It is more preferable that the number is even.

  In the micromirror device of the present invention, the elastic member that connects the tops of the plurality of piezoelectric elements that constitute the piezoelectric actuator array has a plurality of piezoelectric elements that are connected to each other as compared to the vicinity of the tops of the individual piezoelectric elements. It is preferable that the strength of the portion near the center between (at the top) is small and the narrow support portion is provided in the portion near the center of the elastic member.

  The means for reducing the strength in the vicinity of the center is not limited. For example, the material strength may be partially reduced by changing the property of the material in the vicinity of the center. A method of reducing the structural strength by thinning or thinning the vicinity can be adopted.

  In the micromirror device of the present invention, it is preferable that a plurality of micromirrors are provided and the elastic member is provided independently for each micromirror.

  The fact that the elastic member is provided independently means that the elastic member that transmits the expansion / contraction displacement of the piezoelectric element to the micromirror is separated for each micromirror.

  In the micromirror device of the present invention, the surface of the micromirror is a mirror surface, and a piezoelectric actuator array as a drive mechanism is disposed on the backside of the micromirror. The shape of the micromirror is not limited and may be circular, elliptical, or the like. However, as the drive mechanism, a piezoelectric actuator array in which a plurality of piezoelectric elements are preferably arranged in a matrix is used. Therefore, a shape that can increase the effective area of the mirror surface is preferable. For example, a square or a rectangle.

  The micromirror device of the present invention uses a piezoelectric actuator (array) instead of an electrostatic actuator as a driving mechanism of the micromirror, and includes a predetermined elastic member between the micromirror and the piezoelectric actuator array. The expansion / contraction displacement of the element is converted into a rotational displacement in the biaxial direction of the micromirror via the elastic member, and the angle of the micromirror is changed, so that the rigid micromirror is driven at high speed, The angle can be changed.

  In a preferred embodiment of the micromirror device of the present invention, the predetermined elastic member is a portion near the center between the (top portions) of the plurality of piezoelectric elements connected to each other as compared with the portion near the top portion of each piezoelectric element. The narrow support portion is provided in a portion near the center of the elastic member, that is, a portion having a low strength. Therefore, since the deformation of the elastic member is concentrated on the portion where the strength is small, the expansion / contraction displacement expressed by the piezoelectric element can be more efficiently converted to the rotational displacement of the micromirror.

  In the preferred embodiment, the micromirror device of the present invention includes a plurality of micromirrors, and the elastic member is provided separately for each micromirror, so that crosstalk between rotational displacements of adjacent micromirrors is provided. The angle control of the micromirror can be performed with higher accuracy.

  Hereinafter, embodiments of the present invention will be described with appropriate reference to the drawings, but the present invention should not be construed as being limited thereto. Various changes, modifications, improvements, and substitutions can be added based on the knowledge of those skilled in the art without departing from the scope of the present invention. For example, the drawings show preferred embodiments of the present invention, but the present invention is not limited by the modes shown in the drawings or the information shown in the drawings. In practicing or verifying the present invention, the same means as described in this specification or equivalent means can be applied, but preferred means are those described below.

  The piezoelectric element and the piezoelectric actuator array constituting the micromirror device of the present invention are expressed as piezoelectric, but are elements that use strain induced by an electric field and an array-like actuator in which the elements are arranged in a narrow sense. In terms of meaning, it is not limited to elements using a piezoelectric effect that generates a strain amount that is roughly proportional to the applied electric field, but to electrostrictive effects that generate a strain amount that is roughly proportional to the square of the applied electric field, and to all ferroelectric materials. It also includes elements that utilize phenomena such as polarization reversal observed, phase transition between antiferroelectric phase and ferroelectric phase found in antiferroelectric materials, and the like. Whether or not the polarization process is performed is also appropriately determined based on the property of the material applied to the piezoelectric body of the piezoelectric element. The piezoelectric body constituting the piezoelectric element refers to a piezoelectric material (also not narrowly defined) having a fixed shape.

  The micromirror device of the present invention includes a micromirror and a piezoelectric actuator array, and the piezoelectric actuator array is disposed on the back surface of the micromirror. The piezoelectric actuator array is an array of a plurality of piezoelectric elements, and each of the piezoelectric elements develops an expansion / contraction displacement in the normal direction of the mirror surface of the micromirror. The micromirror device of the present invention includes an elastic member between the micromirror and the piezoelectric actuator array, and the elastic member connects the tops of a plurality of piezoelectric elements constituting the piezoelectric actuator array. And the micromirror and the elastic member are connected via the narrow support part provided in the part which connects the said elastic member. In the micromirror device of the present invention having such a configuration, the expansion / contraction displacement of the piezoelectric element is converted to the rotational displacement of the micromirror in two axial directions via the elastic member, and the angle of the micromirror can be changed. It is what.

  Hereinafter, the components of the micromirror device of the present invention will be sequentially described. Incidentally, the micromirror device for explaining the constituent elements is provided with four micromirrors, and four piezoelectric elements are combined with each micromirror.

  First, the piezoelectric actuator array will be described. FIG. 1 is a perspective view showing an embodiment of a piezoelectric actuator array constituting a micromirror device of the present invention, and FIG. 2 is a plan view thereof (top view in FIG. 1). In the illustrated piezoelectric actuator array 10, 16 (= 4 × 4) columnar piezoelectric elements 31 including a piezoelectric body 4 and a pair of electrodes 18 and 19 are arranged on a ceramic substrate 2 in a matrix. This is an array-like actuator formed by firing and integrating the ceramic base 2 and the piezoelectric element 31 (piezoelectric body 4). The electrode 18 is an individual electrode independent for each piezoelectric element, and the electrode 19 is a common electrode common to all piezoelectric elements.

  The individual piezoelectric elements 31 shown in FIG. 1 are expressed as being constituted by one columnar piezoelectric body 4 and a pair of electrodes 18 and 19 sandwiching the piezoelectric body 4. In the micromirror device, a more preferable piezoelectric element has an even number of layered piezoelectric bodies, and layered individual electrodes (for example, corresponding to the electrode 18) and layered common electrodes (for example, corresponding to the electrode 19) are alternately arranged on each surface. The layers are stacked so that the layered common electrode is the outermost layer, and the columnar shape is formed as a whole. Furthermore, the number of piezoelectric layers is preferably an even number of 4 or more. This is because by setting the number of layers to be an even number, the electrodes exposed on the two surfaces of the outermost layer can be made common electrodes, and electrical short-circuiting between adjacent piezoelectric elements is less likely to occur. Further, when the number of layers is 2, the straightness of the displacement may be deteriorated (moves in the left-right direction in FIG. 1) when the thicknesses of the two layers are slightly different. This is because if the number is an even number of 4 or more, the influence due to the difference in thickness of the piezoelectric body can be reduced.

  Each piezoelectric element 31 (piezoelectric body 4) is an element that generates displacement due to the piezoelectric lateral effect. When the lower end of the piezoelectric element 31 is fixed on the ceramic substrate 2 and an electric field E is applied in the same direction as the polarization direction P, , They cause expansion and contraction displacement in the direction of the arrow S (vertical direction in FIG. 1), which is the vertical direction. The piezoelectric actuator array 10 is a micromirror drive mechanism that drives the micromirrors by causing each of the piezoelectric elements 31 to cause such expansion and contraction displacement individually or simultaneously.

  In addition, in the piezoelectric element 31, the side surface on which the electrodes 18 and 19 of the piezoelectric body 4 are formed is an unprocessed fired surface that is not processed at all (see Patent Document 4). As a result, the generation of particles is suppressed for a long period of time, and the mirror surface of the micromirror due to the driving operation of the piezoelectric actuator array 10 is less likely to occur.

  Next, the elastic member will be described. FIG. 3 is a plan view showing an embodiment of an elastic member constituting the micromirror device of the present invention. As shown in the drawing, the elastic member 30 is a sheet-like member having a lattice pattern, and the lattice pattern is the top 7 of the plurality of piezoelectric elements 31 constituting the piezoelectric actuator array 10 (see FIG. 1). The intersection points Q of the 16 existing lattices are positioned at the center of the top portion 7 of the 16 piezoelectric elements 31 and are surrounded by 4 intersection points Q. Narrow support portions that connect the four micromirrors are positioned and provided at the intersection R of the lattice.

  The elastic member 30 has a lattice portion formed with a constant width. As described above, the elastic member has a lattice width in the vicinity of the top of each piezoelectric element (ie, in the vicinity of the intersection Q). Compared to the above, the width of the lattice in the vicinity of the center (ie, the vicinity of the intersection R) between the tops of a plurality of connected piezoelectric elements is narrowed (narrowed) to reduce the structural strength of that portion. May be.

  Moreover, although the elastic member 30 is represented as an integral member in which all the lattice portions are connected, as described above, the elastic member may be independent for each of the four micromirrors. That is, the lattice of the elastic member may be separated so that four intersection points Q corresponding to one micromirror and one intersection point R surrounded by the intersections become one set.

  Next, the micromirror will be described. FIG. 4 is a plan view showing an embodiment of a micromirror constituting the micromirror device of the present invention. The four micromirrors 41 shown in the figure have a square shape, one surface (front surface) is a mirror surface 43, and the other surface (back surface) is provided with a narrow support portion 42 at the center thereof.

  The narrow support portion 42 is formed as a small projection having a substantially cylindrical shape integrated with the micromirror 41, and corresponds to the intersection R of the micromirror 41 and the elastic member 30 (the center between the top portions of the plurality of piezoelectric elements). And the micromirror 41 is supported on the elastic member 30.

  FIG. 5 is a diagram showing the positional relationship of the piezoelectric actuator array 10, the elastic member 30 and the micromirror 41 superimposed on each other. In other words, the micromirror device of the present invention using these as constituent elements. It is the top view which saw through the inside. Referring to FIGS. 2, 3, and 4 together, the elastic member 30 having a lattice pattern is connected to the tops 7 of the plurality of piezoelectric elements 31 constituting the piezoelectric actuator array 10, and 16 The intersection point Q of the existing grid is positioned at the center of the top 7 of the 16 piezoelectric elements 31, and the four micromirrors 41 are connected to the intersection point R of the four grids surrounded by every four intersection points Q. It can be understood that the narrow support portion 42 is positioned.

  6 (a), 6 (b), and 7 show microscopic deformation due to expansion and contraction of four piezoelectric elements 31 (for convenience, the piezoelectric elements 31a, 31b, 31c, and 31d, respectively) constituting the piezoelectric actuator array 10. FIG. FIGS. 6A and 6B are side views and FIGS. 7A and 7B are perspective views showing how the angle of the mirror 41 (mirror surface 43) is changed.

  FIG. 6A shows a state in which none of the piezoelectric elements is OFF (no electric field is applied), and the micromirror 41 is directed substantially straight upward. In FIG. 6B, by applying an electric field to the piezoelectric elements 31a and 31b with the piezoelectric elements 31c and 31d turned off, the piezoelectric elements 31a and 31b are not displaced and the piezoelectric elements 31a and 31b are displaced upward. As a result, the elastic support member 30 that connects the tops of the piezoelectric elements 31a (31b) and 31c (31d) is bent at a portion near the center of the elastic member 30 (the portion near the intersection R). 42 is tilted, through which the angle of the micromirror 41 (of the mirror surface 43) is changed. Note that the same operation may be performed by displacing the piezoelectric elements 31c and 31d downward without displacing the piezoelectric elements 31a and 31b.

  FIG. 7 shows a state in which only the piezoelectric element 31d is not displaced and the piezoelectric elements 31a, 31b, and 31c are displaced upward (or only the piezoelectric element 31d is displaced downward without displacing the piezoelectric elements 31a, 31b, and 31c). The elastic member 30 that connects the top portions of the piezoelectric elements 31a, 31b, 31c, and 31d is bent near the center (the vicinity of the intersection R) and the narrow support portion 42 is inclined. Through this, the angle (of the mirror surface 43) of the micromirror 41 changes.

  Next, the method for producing the micromirror device of the present invention will be described together with the materials used. The micromirror device of the present invention can be obtained by fabricating and assembling a piezoelectric actuator array, an elastic member, a micromirror, and, if necessary, independent members that serve as a narrow support portion. Hereinafter, the case where the above-described piezoelectric actuator array 10, the elastic member 30, and the micromirror 41 are produced and assembled to produce a micromirror device will be described as an example.

  About the method and material which produce the piezoelectric actuator array 10, it shall follow the description of patent document 4, and description is abbreviate | omitted. It is preferable to use a green sheet lamination method as a manufacturing method, and to use a lead zirconate titanate (PZT) ceramic material or the like. Specifically, it is described in the section of Patent Document 4 on the method and material for producing a low dust generation matrix type piezoelectric (/ electrostrictive) device.

  The elastic member 30 may be obtained by obtaining a commercially available sheet-like elastic material and processing it into a lattice pattern by a processing means such as punching, etching, or laser processing. As the elastic material, a metal such as stainless steel or a resin material such as polyimide is preferably used.

  The micromirror 41 is obtained by obtaining a square mirror substrate and coating one surface thereof with a highly reflective material to form a mirror surface. As the material of the mirror substrate, metal, silicon, ceramic, or the like can be used. Silicon is more desirable because a plate-like material with high surface flatness is readily available. Gold, aluminum, or the like is preferably used as a material to be coated on the mirror substrate. As a coating method, a sputtering method, a vapor deposition method, a plating method, or the like is preferably employed.

  The narrow support portion 42 can be formed as, for example, a protrusion integrated on the micromirror 41 side. Specifically, a protrusion may be formed on the back surface of the mirror substrate by etching or the like, and this may be used as a narrow support portion 42, or the adhesive is raised only at the connection point with the elastic member 30 on the back surface of the mirror substrate. It is good also as application | coating so that a projection part may be formed and making it the narrow support part 42. FIG. Furthermore, a protrusion may be formed on the elastic member 30 (intersection R portion) side.

  Next, assembly will be described. First, the elastic member 30 having a lattice pattern is fixed to the piezoelectric actuator array 10 so that the 16 intersections Q are positioned at the centers of the tops 7 of the 16 piezoelectric elements 31. This fixing is desirably performed by adhering a portion where the elastic member 30 and the top portion 7 of the piezoelectric element 31 are in contact with each other. In this fixed state, unnecessary portions of the elastic member 30 may be separated so that the elastic member 30 is provided independently for each micromirror 41 later. As a method of separating, means such as machining such as wire saw processing and laser processing can be applied. As described above, a conversion mechanism constituted by the piezoelectric actuator array 10 and the elastic member 30 (without the micro mirror 41) for changing the expansion / contraction displacement of the piezoelectric element 31 to the rotational displacement in the biaxial direction is obtained.

  Next, four micromirrors 41 are attached to the conversion mechanism. This attachment is performed so that the narrow support portions 42 provided on the back surface of each micromirror 41 are positioned and connected to the four intersections R of the elastic member 30. As a specific desirable mounting means, four micromirrors 41 are arranged in advance on the temporary fixing means with the back side facing up, and an adhesive is applied to the narrow support portion 42 so that the rotating mechanism A method of separating the temporary fixing means after bonding can be mentioned. As the temporary fixing means, a method of fixing to a jig with wax or the like, or a method of using a UV (ultraviolet) peeling tape, a thermal foaming sheet or the like can be adopted.

  The micromirror device of the present invention is suitably used for an optical switch, an optical scanner, an image display device, and the like.

It is a perspective view which shows one Embodiment of the piezoelectric actuator array which comprises the micromirror device of this invention. FIG. 2 is a plan view of the piezoelectric actuator array shown in FIG. 1. It is a top view which shows one Embodiment of the elastic member which comprises the micromirror device of this invention. It is a top view which shows one Embodiment of the micromirror which comprises the micromirror device of this invention. FIG. 5 is a plan view in which the piezoelectric actuator array shown in FIG. 2, the elastic member shown in FIG. 3, and the micromirror shown in FIG. 4 are superimposed. It is a figure showing a mode that the angle of a micromirror is changed by expansion-contraction displacement of a plurality of piezoelectric elements which constitute a piezoelectric actuator array, and is a side view showing a state before the angle is changed. It is a figure showing a mode that the angle of a micromirror is changed by expansion-contraction displacement of a plurality of piezoelectric elements which constitute a piezoelectric actuator array, and is a side view showing the state after the angle was changed. It is a figure showing a mode that the angle of a micromirror is changed by expansion-contraction displacement of a plurality of piezoelectric elements which constitute a piezoelectric actuator array, and is a perspective view showing the state after the angle was changed. It is a top view which shows an example of the conventional micromirror device. It is a figure showing the AA 'cross section in Fig.8 (a).

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 ... Ceramic base | substrate, 4 ... Piezoelectric body, 7 ... Top part, 10 ... Piezoelectric actuator array, 18, 19 ... Electrode, 30 ... Elastic member, 31 ... Piezoelectric element, 41 ... Micromirror, 42 ... Narrow support part, 43 ... Mirror surface 80 ... (conventional) micromirror device, 81 ... micromirror, 82 ... torsion bar, 83 ... electrode, 84 ... mirror mounting part.

Claims (3)

A micro-mirror and a piezoelectric actuator array in which a plurality of piezoelectric elements that express expansion and contraction are arranged in the normal direction of the mirror surface of the micro-mirror, and the piezoelectric actuator array is disposed on the back surface of the micro-mirror A micromirror device,
Between the micromirror and the piezoelectric actuator array, an elastic member for connecting the tops of a plurality of piezoelectric elements constituting the piezoelectric actuator array is provided,
The micromirror and the elastic member are connected via a narrow support portion provided in the connecting portion of the elastic member,
A micromirror device in which the expansion and contraction displacement of the piezoelectric elements constituting the piezoelectric actuator array is converted into a rotational displacement in the biaxial direction of the micromirror via the elastic member. In the piezoelectric actuator array, the plurality of piezoelectric elements have a columnar shape, are arranged in a matrix on one surface of a ceramic base, and are integrally formed by firing with the ceramic base. Is an element that produces
The micromirror device according to claim 1, wherein the elastic member is a sheet-like member having a lattice pattern.   The elastic member that connects the tops of the plurality of piezoelectric elements constituting the piezoelectric actuator array has a strength in the vicinity of the center between the plurality of piezoelectric elements related to the connection compared to the vicinity of the tops of the individual piezoelectric elements. The micromirror device according to claim 1, wherein the narrow support portion is provided in the vicinity of the center of the elastic member.

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