JP2014190986A - Hinge and mirror device with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease the stiffness of a hinge in a predetermined direction, and to increase the stiffness of the hinge in another direction.SOLUTION: A mirror device 100 includes a mirror 131, an actuator 104, and a first hinge 105 for supporting the mirror 131. The first hinge 105 has a first meandering portion 151 which is formed in a zigzag shape by a plurality of first projecting portions 155 and a plurality of first recessed portions 156, and which extends from one end portion to the other end portion while meandering; and a second meandering portion 152 which is formed in a zigzag shape by a plurality of second projecting portions 157 and a plurality of second recessed portions 158, which is arranged in parallel with the first meandering portion 151 portion, and extends from one end portion to the other end portion while meandering. The first recessed portions 156 and the second recessed portions 158 are coupled with each other.

Description

  The technology disclosed herein relates to a hinge and a mirror device including the hinge.

  Conventionally, various mirror devices are known. The mirror device disclosed in Patent Document 1 includes an actuator, a mirror, a hinge that connects the actuator and the mirror, and is elastically deformable. This mirror device tilts the mirror by tilting the actuator. At this time, the hinge is bent or stretched in the direction in which the actuator and the mirror are arranged.

JP 2009-229916 A

  By the way, the hinge as described above is required to have various characteristics according to the purpose of use. For example, there is a case where a large rigidity is required and a case where a small rigidity is required. Alternatively, it may be different depending on the direction whether the rigidity should be increased or decreased.

  For example, in the mirror device, the rigidity of the hinge in the direction connecting the one end and the other end of the hinge is small, and the rigidity of the hinge in the direction perpendicular to the direction (hereinafter referred to as “width direction”) is large. Is preferred. That is, when the mirror is tilted by tilting the actuator, the hinge is bent. At this time, the hinge extends in a direction connecting the one end and the other end of the hinge. In order not to inhibit the tilting of the actuator, the rigidity of the hinge in the direction connecting the one end and the other end of the hinge is preferably small. On the other hand, if the rigidity of the hinge in the width direction is small, the mirror is easily displaced in the width direction, and the mirror is likely to come into contact with surrounding structures. If the mirror contacts the surrounding structure, the mirror may be damaged. Therefore, it is preferable that the rigidity of the hinge in the width direction is large.

  By changing the material and thickness of the hinge, it is easy to simply increase or decrease the rigidity of the hinge. However, when the requirements for the rigidity of the hinge differ depending on the direction, it is difficult to adjust the rigidity of the hinge as required by a method of simply changing the material and thickness of the hinge. For example, by reducing the thickness of the hinge, the rigidity of the hinge in the direction in which the actuator and the mirror are arranged can be reduced, but the rigidity of the hinge in the width direction is naturally reduced.

  The technology disclosed herein has been made in view of the above points, and the object is to reduce the rigidity of the hinge in a predetermined direction and increase the rigidity of the hinge in another direction. is there.

  The mirror device disclosed herein includes a mirror, an actuator that drives the mirror, and a first hinge that supports the mirror and is elastically deformable, and the first hinges are alternately arranged. A plurality of first convex portions and a plurality of first concave portions are formed in a zigzag shape, the first meandering portions extending from the one end portion to the other end portion while meandering, and the plurality of second convex portions arranged alternately. And a plurality of second recesses formed in a zigzag shape, arranged in parallel with the first meandering portion, and having a second meandering portion extending from the one end portion to the other end portion while meandering, and at least a part of The first recess and at least a portion of the second recess are connected to each other.

  In other words, the hinges disclosed herein are connected to the first member at one end and connected to the second member at the other end, and are elastically deformable. The zigzag is formed by the convex portions and the plurality of first concave portions, and the first meander portions extending from the one end portion to the other end portion while meandering, the plurality of second convex portions and the plurality of second convex portions arranged alternately. A second meandering portion that extends from the one end to the other end while meandering, and is formed in a zigzag shape with two recesses, and at least a portion of the first recess, It is assumed that at least some of the second recesses are connected to each other.

  According to the above configuration, since the first meandering portion and the second meandering portion are formed in a zigzag shape and extend from one end portion to the other end portion while meandering, the first meandering portion and the other end portion are connected in the first direction. The rigidity of one hinge (or hinge) can be made relatively small. In addition, by connecting at least a part of the first recesses of the first meandering part and at least a part of the second recesses of the second meandering part, the first and second recesses cannot be freely displaced. Therefore, the rigidity of the first hinge in the direction in which the first meandering portion and the second meandering portion meander can be made relatively large as compared with a configuration in which the first concave portion and the second concave portion can be freely displaced. Thereby, in one hinge, the rigidity in one direction can be reduced and the rigidity in another direction can be increased.

  Further, since the first hinge is easily expanded and contracted in the direction connecting the one end and the other end, in the mirror device, the mirror can be easily driven by the actuator. On the other hand, it is possible to prevent the mirror from colliding with surrounding members by increasing the rigidity of the first hinge in the meandering direction.

  According to the mirror device, the rigidity of the hinge in a predetermined direction can be reduced, and the rigidity of the hinge in another direction can be increased.

It is a top view of a mirror array. It is sectional drawing in the II-II line | wire of FIG. 1 of a mirror array. It is the schematic of a wavelength selective switch. It is a top view of the 1st hinge. It is a top view of the hinge model of a 1st hinge. It is a top view of the comparison model of the 1st hinge. It is a table | surface which shows the material physical-property value of a hinge model and a comparison model. It is a graph which shows the relationship between each number N of a 1st convex part and a 2nd convex part, and Kx. It is a graph which shows the relationship between each number N of a 1st convex part and a 2nd convex part, and Ky. It is a top view of a comparative model when the tensile force Fy is applied. It is a top view of the mirror array which concerns on a modification. It is a top view of the 1st hinge concerning the modification 1. 10 is a plan view of a first hinge according to Modification 2. FIG. 6 is a plan view of a mirror device according to Embodiment 2. FIG. It is a top view of the mirror device which concerns on a modification.

  Hereinafter, exemplary embodiments will be described in detail with reference to the drawings.

Embodiment 1
FIG. 1 is a plan view of the mirror array 1, and FIG. 2 is a cross-sectional view of the mirror array 1 taken along line II-II in FIG.

  The mirror array 1 includes a plurality of mirror devices 100, 100,. A plurality of mirror devices 100, 100,... Are arranged in a line in a predetermined Y-axis direction.

The mirror array 1 is manufactured using an SOI (Siliconon Insulator) substrate 109 (see FIG. 2). The SOI substrate 109 includes a first silicon layer 191 formed of single crystal silicon, an oxide film layer 192 formed of SiO ₂ , and a second silicon layer 193 formed of single crystal silicon in this order. Configured.

  The mirror device 100 includes a base portion 102, a mirror 131, an actuator 104 that drives the mirror 131, a first hinge 105 that connects the mirror 131 and the actuator 104, and a second that connects the mirror 131 and the base portion 102. It has a hinge 106, a movable comb electrode 107 provided on the mirror 131, a fixed comb electrode 108 provided on the base portion 102, a reference electrode 194, and a control unit 10. The mirror array 1 has one common control unit 10 for each of several mirror devices 100, 100,. The mirror array 1 may have one control unit 10 for each mirror device 100, or may have one control unit 10 common to all mirror devices 100, 100,.

  Although the entire illustration of the base portion 102 is omitted, the base portion 102 is formed in a substantially rectangular frame shape. The base portion 102 is formed of a first silicon layer 191, an oxide film layer 192, and a second silicon layer 193.

  The mirror 131 is formed in a rectangular plate shape in plan view. The mirror 131 includes a mirror main body 132 and a mirror surface layer 133 stacked on the surface of the mirror main body 132. The mirror body 132 is formed of a first silicon layer 191 and the mirror surface layer 133 is formed of an Au / Ti film. A mirror layer 134 similar to the mirror layer 133 is also laminated on the back surface of the mirror main body 132. The mirror surface layer 134 has a function of balancing film stress caused by the mirror surface layer 133 generated on the surface of the mirror main body 132. Thereby, the flatness of the mirror main body 132, and hence the mirror surface layer 133, can be improved.

  Here, an axis passing through the center of the mirror 131 and extending in the direction in which the mirror 131 and the actuator 104 are arranged is defined as an X axis. The X axis extends parallel to the long side of the mirror 131. An axis passing through the center of the mirror 131 and extending in parallel with the short side of the mirror 131 is defined as a Y axis. The X axis and the Y axis are orthogonal. The plurality of mirrors 131, 131,... Are arranged on the Y axis. That is, the arrangement direction of the plurality of mirrors 131, 131,... Matches the Y-axis direction. An axis orthogonal to both the X axis and the Y axis is taken as a Z axis. The Z-axis direction is sometimes referred to as the up-down direction. In that case, the side of the mirror surface layer 133 is the top, and the side of the mirror body 132 is the bottom.

  The actuator 104 extends in a cantilevered manner from the base portion 102, and its tip is connected to the mirror 131 via the first hinge 105. The actuator 104 tilts the mirror 131 by bending. Specifically, the actuator 104 has an actuator main body 141 whose base end portion is connected to the base portion 102 and projects from the base portion 102 in a cantilever manner, and a piezoelectric element 142 stacked on the surface of the actuator main body 141. ing.

  The actuator main body 141 is formed in a rectangular plate shape in plan view. The actuator body 141 is formed of the first silicon layer 191. The actuator body 141 extends in the X-axis direction. The tip of the actuator main body 141 is connected to the first short side 131 a that is one short side of the mirror 131 via the first hinge 105.

The piezoelectric element 142 is provided on the front side of the actuator main body 141 (the same side as the mirror surface layer 133 of the mirror 131). A SiO ₂ layer 146 is laminated on the surface of the actuator body 141, and the piezoelectric element 142 is laminated on the SiO ₂ layer 146. The piezoelectric element 142 is formed in a plate shape having a rectangular shape in plan view, similarly to the actuator body 141. The piezoelectric element 142 includes a lower electrode 143, an upper electrode 145, and a piezoelectric layer 144 sandwiched therebetween. The lower electrode 143, the piezoelectric layer 144, and the upper electrode 145 are laminated on the SiO ₂ layer 146 in this order. The piezoelectric element 142 is formed of a member different from the SOI substrate 109. Specifically, the lower electrode 143 is formed of a Pt / Ti film. The piezoelectric layer 144 is made of lead zirconate titanate (PZT). The upper electrode 145 is formed of an Au / Ti film.

  The base portion 102 is provided with a driving terminal 121 that is electrically connected to the lower electrode 143. A voltage is applied to the piezoelectric element 142 via the upper electrode 145 and the drive terminal 121.

  In the actuator 104, when a voltage is applied to the piezoelectric element 142, the surface of the actuator main body 141 on which the piezoelectric element 142 is laminated expands and contracts, and the actuator main body 141 is bent in the vertical direction.

  The first hinge 105 connects two members, that is, the actuator 104 and the mirror 131, and is configured to be elastically deformable. The first hinge 105 is formed of the first silicon layer 191. A detailed configuration of the first hinge 105 will be described later.

  The second hinge 106 connects two members, that is, the mirror 131 and the base portion 102, and is configured to be elastically deformable. Two second hinges 106 are provided for each mirror 131. One end of the second hinge 106 is connected to the second short side 131 b of the mirror 131, and the other end is connected to the base portion 102. The second hinge 106 is bent in a zigzag shape as a whole. The second hinge 106 is formed of the first silicon layer 191.

  The movable comb electrode 107 is provided in a cantilever manner on the second short side 131 b of the mirror 131 via the arm portion 179. The arm part 179 extends between the two second hinges 106 in the X-axis direction. The movable comb electrode 107 has three electrode fingers 171, 171,. The electrode finger 171 is farther from the mirror 131 than the second hinge 106. The three electrode fingers 171, 171,... Extend in the X-axis direction in parallel with each other. The movable comb electrode 107 and the arm portion 179 are formed of the first silicon layer 191. The number of electrode fingers 171 is not limited to three.

  On the other hand, the base portion 102 is formed with a concave portion 102a into which the movable comb electrode 107 enters. A fixed comb electrode 108 is provided in the recess 102a. The fixed comb electrode 108 has two electrode fingers 181 and 181. The two electrode fingers 181 and 181 extend in the X-axis direction in parallel with each other. Each electrode finger 181 enters between the electrode fingers 171 of the movable comb electrode 107. That is, the electrode finger 171 of the movable comb electrode 107 and the electrode finger 181 of the fixed comb electrode 108 face each other. The fixed comb electrode 108 is formed of the first silicon layer 191. However, the fixed comb electrode 108 is electrically insulated from the movable comb electrode 107. The number of electrode fingers 181 is not limited to two.

  The base portion 102 is provided with a first detection terminal 122 and a second detection terminal 123 for detecting the electrostatic capacitance between the movable comb electrode 107 and the fixed comb electrode 108.

  The first detection terminal 122 is provided on the surface of the portion of the first silicon layer 191 of the base portion 102 that is electrically connected to the movable comb electrode 107. The first detection terminal 122 is common to the plurality of movable comb electrodes 107, 107,..., And only one is provided. Note that the first detection terminal 122 may be provided for each mirror device 100.

  The second detection terminal 123 is provided on the surface of the electrode portion 124. The electrode portion 124 is formed of the first silicon layer 191 of the base portion 102, is isolated from the surrounding portions on the oxide film layer 192 of the base portion 102, and is electrically insulated. The electrode portion 124 is connected to the fixed comb electrode 108. The second detection terminal 123 and the electrode unit 124 are provided for each fixed comb electrode 108.

  In addition, a reference electrode 194 is provided on the base portion 102. The reference electrode 194 includes a first electrode finger 194 a corresponding to the electrode finger 171 of the movable comb electrode 107 and a second electrode finger 194 b corresponding to the electrode finger 181 of the fixed comb electrode 108. The first electrode finger 194 a and the second electrode finger 194 b have the same configuration as the electrode finger 171 and the electrode finger 181. That is, three first electrode fingers 194a are provided, and two second electrode fingers 194b are provided. The second electrode finger 194b penetrates between the first electrode fingers 194a. That is, the first electrode finger 194a and the second electrode finger 194b face each other.

  The capacitance of the reference electrode 194 is detected via the first detection terminal 122 and the third detection terminal 125.

  The first electrode finger 194a is electrically connected to a portion of the first silicon layer 191 of the base portion 102 where the first detection terminal 122 is provided.

  The third detection terminal 125 is provided on the surface of the electrode portion 126. The electrode part 126 has the same configuration as the electrode part 124. That is, the electrode portion 126 is formed of the first silicon layer 191 of the base portion 102, is isolated from the surrounding portions on the oxide film layer 192 of the base portion 102, and is electrically insulated. The electrode part 126 is connected to the second electrode finger 194b.

  The oxide film layer 192 and the second silicon layer 193 are removed below the mirror 131, the actuator 104, the first hinge 105, the second hinge 106, the movable comb electrode 107, the fixed comb electrode 108, and the reference electrode 194. Has been.

  In addition, a partition wall 102b is provided between the fixed comb electrodes 108, 108 of the adjacent mirror devices 100, 100. That is, the adjacent recesses 102a and 102a are separated by the partition wall 102b. The partition wall 102 b is formed of a first silicon layer 191, an oxide film layer 192, and a second silicon layer 193.

The mirror array 1 configured as described above is manufactured by etching the SOI substrate 109 or forming a film on the surface thereof. For example, by forming a SiO ₂ layer 146 on the surface of the SOI substrate 109, on top of the SiO ₂ layer 146, Pt / Ti film (lower electrode 143), lead zirconate titanate (piezoelectric layer 144) and Au / Ti A film (upper electrode 145) is sequentially formed, and the piezoelectric element 142 is formed by photolithography and etching. Next, the mirror body 132, the actuator body 141, and the like are formed by performing anisotropic etching such as ICP-RIE on the first silicon layer 191. Subsequently, an Au / Ti film is formed on the surface of the mirror main body 132 to form the mirror surface layer 133. Thereafter, a predetermined voltage is applied to the piezoelectric element 142 to perform polarization processing.

-Wavelength selective switch-
The mirror array 1 is used by being incorporated in a wavelength selective switch 2, for example. FIG. 3 shows a schematic diagram of the wavelength selective switch 2.

  The wavelength selective switch 2 includes one input optical fiber 21, three output optical fibers 22 to 24, a collimator 25 provided in the optical fibers 21 to 24, a spectroscope 26 configured by a diffraction grating, The lens 27 and the mirror array 1 are provided. In this example, there are only three output fibers, but the present invention is not limited to this.

  In the wavelength selective switch 2, optical signals having a plurality of different wavelengths are input via the input optical fiber 21. This optical signal is collimated by the collimator 25. The optical signal that has become parallel light is demultiplexed by the spectroscope 26 into optical signals having a predetermined number of specific wavelengths. The demultiplexed optical signal is collected by the lens 27 and enters the mirror array 1. The number of specific wavelengths to be demultiplexed corresponds to the number of mirrors 131 in the mirror array 1. That is, the demultiplexed optical signals having specific wavelengths are incident on the corresponding mirrors 131, respectively. Then, the optical signal is reflected by each mirror 131, passes through the lens 27 again, and enters the spectroscope 26. The spectroscope 26 multiplexes the optical signals having a plurality of different wavelengths and outputs them to the output optical fibers 22 to 24. Here, the mirror array 1 adjusts the reflection angle of the optical signal by tilting each mirror 131, and switches which output optical fiber 22 to 24 the corresponding optical signal is input to. The number of mirrors 131 may be larger than the number of specific wavelengths to be demultiplexed.

-Operation of mirror array-
Next, the operation of the mirror array 1 configured as described above will be described.

  Since the piezoelectric element 142 is formed on the actuator body 141, the actuator 104 is warped (hereinafter referred to as “initial warp”) when no voltage is applied to the piezoelectric element 142. The mirror 131 is inclined due to this initial warpage. The initial warpage varies for each actuator 104. Therefore, the inclination of the mirror 131 is also different.

  Therefore, when the mirror array 1 is operated, first, initial bias is adjusted by applying a bias voltage to the piezoelectric element 142. Thereby, the inclination of the mirrors 131, 131,... Is made uniform. Specifically, the control unit 10 applies a bias voltage to the upper electrode 145 and the lower electrode 143. When the polarity of the bias voltage is the same as the polarity of the voltage during the polarization process, the piezoelectric layer 144 contracts according to the bias voltage. Accordingly, the surface of the actuator main body 141 on the piezoelectric element 142 side contracts. As a result, the warpage state of the actuator body 141 changes.

  When the warpage state of the actuator body 141 changes, the tip of the actuator body 141 is displaced. Accordingly, the first short side 131a of the mirror 131 is similarly displaced. Since the second short side 131b of the mirror 131 is connected to the base portion 102 via the second hinge 106, the second short side 131b is hardly displaced. As a result, the mirror 131 tilts so that the first short side 131a side is displaced with the second hinge 106 as a fulcrum.

  Then, the control unit 10 adjusts the bias voltage based on the electrostatic capacitance between the movable comb electrode 107 and the fixed comb electrode 108, which will be described later in detail, so that the inclination of the mirrors 131, 131,. To do.

  Thus, in the initial state, a bias voltage is applied to the piezoelectric element 142, and the inclinations of the mirrors 131, 131,... Are uniformly adjusted.

  From this state, the control unit 10 applies a drive voltage to the desired mirror device 100 to individually control the mirror 131. The mirror 131 tilts in accordance with the drive voltage, similar to when a bias voltage is applied. In other words, the mirror 131 tilts around the A axis that is parallel to the Y axis and substantially passes through the second hinge 106. At this time, the first hinge 105 is curved in a convex shape, and the second hinge 106 is curved in a concave shape.

-Detection of mirror tilt amount-
When the mirror 104 is tilted by operating the actuator 104, the movable comb electrode 107 is also tilted accordingly. Since the movable comb electrode 107 is located on the opposite side of the mirror 131 with the second hinge 106 interposed therebetween, for example, when the mirror 131 is tilted so as to raise the first short side 131a, the movable comb electrode 107 is moved to the electrode finger. Tilt to lower 171. As a result, the area of the portion where the electrode finger 171 of the movable comb electrode 107 and the electrode finger 181 of the fixed comb electrode 108 face each other changes, and the area between the movable comb electrode 107 and the fixed comb electrode 108 changes. The capacitance changes.

  The control unit 10 detects the electrostatic capacitance between the movable comb electrode 107 and the fixed comb electrode 108 via the first detection terminal 122 and the second detection terminal 123. The control unit 10 controls the tilt amount of the mirror 131 by adjusting the voltage applied to the piezoelectric element 142 based on the change in capacitance.

  At this time, the control unit 10 also detects the capacitance of the reference electrode 194 via the first detection terminal 122 and the third detection terminal 125. The control unit 10 can obtain the change in the capacitance between the movable comb electrode 107 and the fixed comb electrode 108 more accurately by referring to the capacitance of the reference electrode 194.

  Here, when the area of the electrode finger 171 facing the electrode finger 181 decreases, the capacitance between the movable comb electrode 107 and the fixed comb electrode 108 decreases. When the electrostatic capacity becomes zero, a change in the electrostatic capacity cannot be detected, so that the tilt of the mirror 131 cannot be detected. Here, as in the present embodiment, in the configuration in which the ratio of the dimension of the electrode finger 171 and the electrode finger 181 in the thickness direction of the SOI substrate 109 to the distance between the electrode finger 171 and the electrode finger 181 is small, the electrode finger 171. A fringe effect occurs in which the electric field spreads in a direction other than the direction in which the electrode fingers 181 face each other. Therefore, even if the electrode finger 171 does not face the electrode finger 181, an electric field can be generated between the electrode finger 171 and the electrode finger 181 if the electrode finger 171 and the electrode finger 181 are close to each other. However, if the electrode finger 171 and the electrode finger 181 are greatly separated from each other, the electrostatic capacity becomes zero as well. If this happens, the tilt amount of the mirror 131 cannot be detected. In other words, the range in which the tilt amount of the mirror 131 can be accurately controlled is limited to the range in which the electrostatic capacitance between the movable comb electrode 107 and the fixed comb electrode 108 can be detected.

  The movable comb electrode 107 is disposed closer to the second hinge 106 than the first hinge 105. That is, the movable comb electrode 107 is provided in the vicinity of the A axis of the mirror 131. Therefore, the amount of displacement of the movable comb electrode 107 when the mirror 131 tilts is suppressed. As a result, the tilting range of the mirror 131 that can detect the capacitance can be expanded. That is, the tilting range of the mirror 131 that can accurately control the tilting amount of the mirror 131 can be expanded.

  In such a configuration, if the tilt angle of the mirror 131 from the horizontal plane (for example, the surface of the base portion 102) is the same, the mirror 131 tilts upward even when the mirror 131 tilts downward. Even if it is, the detection result of the capacitance is the same. Therefore, in the operation of the mirror array 1 described above, the bias voltage and the drive voltage are set so that the mirror 131 does not tilt across the horizontal plane when the mirror 131 is driven. That is, (i) the actuator 104 is curved upward from the horizontal plane due to the initial warp, the warp is further adjusted upward by the bias voltage, and the actuator 104 is further curved upward by the drive voltage; and (ii) the initial A case where the actuator 104 is bent below the horizontal plane due to the warp, the actuator 104 is bent above the horizontal plane by the bias voltage, and the actuator 104 is further bent upward by the drive voltage; and (iii) the actuator is caused by the initial warp. 104 is curved below the horizontal plane, the actuator 104 is adjusted upward in the range below the horizontal plane by the bias voltage, and the actuator 104 is curved further upward in the range below the horizontal plane by the drive voltage (I.e. It is not) and sometimes Yueta 104 is curved upward than the horizontal plane. Such an operation of the actuator 104 is an example.

-Configuration of the first hinge-
Next, the configuration of the first hinge 105 will be described in detail. FIG. 4 is a plan view of the first hinge 105.

  The first hinge 105 includes a meandering portion 150, a first end 153, and a second end 154. The meandering part 150 has a first meandering part 151 and a second meandering part 152 arranged side by side. The first meandering portion 151 and the second meandering portion 152 have a line-symmetric shape with respect to the X axis. One end of the first meandering part 151 and one end of the second meandering part 152 are connected to the first end 153. The other end portion of the first meandering portion 151 and the other end portion of the second meandering portion 152 are connected to the second end portion 154. The first end 153 is connected to the actuator 104. The second end 154 is connected to the mirror 131.

  The first meandering portion 151 has three first convex portions 155, 155,... And two first concave portions 156, 156 arranged alternately, and is formed in a zigzag shape. The first meandering portion 151 extends from the first end 153 to the second end 154 in the X-axis direction while meandering in the Y-axis direction. The first convex portion 155 and the first concave portion 156 are each formed in a rectangular shape. The first convex portion 155 extends outward in the Y-axis direction, bends twice at a right angle, turns back, and extends inward in the Y-axis direction. The first recess 156 extends inward in the Y-axis direction, bends twice at a right angle, turns back, and extends outward in the Y-axis direction.

  The second meandering part 152 has three second convex parts 157, 157,... And two second concave parts 158, 158 arranged alternately, and is formed in a zigzag shape. The second meandering part 152 extends from the first end 153 to the second end 154 in the X-axis direction while meandering in the Y-axis direction. The second convex portion 157 and the second concave portion 158 are each formed in a rectangular shape. The second convex portion 157 extends outward in the Y-axis direction, bends twice at a right angle, turns back, and extends inward in the Y-axis direction. The second recess 158 extends inward in the Y-axis direction, bends twice at a right angle, turns back, and extends outward in the Y-axis direction.

  The two first recesses 156 and 156 and the two second recesses 158 and 158 are connected to each other. That is, the first meandering portion 151 and the second meandering portion 152 are connected to the first concave portion 156 and the second concave portion 158 in addition to both end portions.

  In other words, the first hinge 105 has a plurality of annular portions arranged in the X-axis direction and a connecting portion that connects the annular portions. The annular portion has a shape that is longer in the Y-axis direction than in the X-axis direction.

-Rigidity of the first hinge-
Next, the rigidity of the first hinge 105 will be described.

  In order to calculate the rigidity of the first hinge 105, a model shown in FIGS. FIG. 5 shows a hinge model M1 of the first hinge 105, and FIG. 6 shows a comparative model M2.

  The hinge model M1 has the same configuration as the first hinge 105. Specifically, the hinge model M1 includes a meandering portion 150, a first end portion 153, and a second end portion 154. The meandering part 150 has a first meandering part 151 and a second meandering part 152 arranged side by side. The first meandering part 151 has eight first convex parts 155, 155,... And seven first concave parts 156, 156,. The second meandering part 152 has eight second convex parts 157, 157,... And seven second concave parts 158, 158,. The seven first recesses 156, 156,... And the seven second recesses 158, 158,.

  The comparison model M2 includes a first meandering part 151 and a second meandering part 152. The first meandering part 151 has eight first convex parts 155, 155,... And seven first concave parts 156, 156,. The second meandering part 152 has eight second convex parts 157, 157,... And seven second concave parts 158, 158,. The seven first recesses 156, 156,... And the seven second recesses 158, 158,... Are close to each other but are not connected. The first meandering portion 151 and the second meandering portion 152 are not connected at both ends of the comparative model M2.

  Regarding the dimensions of the hinge model M1 and the comparative model M2, the width of the hinge lines is 3 μm, the distance between the hinge lines is 3 μm, the thickness of the hinge lines is 10 μm, and the total width in the Y-axis direction is 120 μm.

  The material of the hinge model M1 and the comparative model M2 is silicon, and the crystal orientation as shown in FIG. 5 is set. FIG. 7 shows material property values of the hinge model M1 and the comparative model M2.

In the X-axis direction, one end of the hinge model M1 and the comparison model M2 is a fixed end, and a tensile force Fx in the X-axis direction of 1 × 10 ⁻⁵ N is applied to the other end of the hinge model M1 and the comparison model M2. The displacement amount in the X-axis direction is defined as δx, and Kx is defined as follows.

Kx = Fx / δx
It becomes. Kx is a value corresponding to the spring constant of the hinge model M1 and the comparison model M2 in the X-axis direction. Hereinafter, Kx is referred to as “stiffness in the X-axis direction”.

In the Y-axis direction, one end of the hinge model M1 and the comparison model M2 is a fixed end, and a tensile force Fy of 1 × 10 ⁻⁵ N in the Y-axis direction is applied to the other end of the hinge model M1 and the comparison model M2. At this time, the other end of the hinge model M1 and the comparison model M2 is prohibited from displacement in the X-axis direction, and the constraint condition is set so that it can be displaced only in the Y-axis direction and the Z-axis direction. The displacement amount in the Y-axis direction is defined as δy, and Ky is defined as follows.

Ky = Fy / δy
It becomes. The reason for setting such a constraint condition is that the behavior of the model approximates the behavior of the first hinge 105 in the actual mirror device 100. Ky is a value related to the rigidity of the hinge model M1 and the comparison model M2 in the Y-axis direction. For convenience of explanation, Ky is hereinafter referred to as “Y-axis direction rigidity”.

  Under such conditions, ANSYS Workbench Mechanical version 14.0 was used, and the stiffness Kx in the X-axis direction and the stiffness Ky in the Y-axis direction were obtained by static structural analysis. At this time, the number N of the first protrusions 155 and the second protrusions 157 of the hinge model M1 and the comparison model M2 is changed, and the X-axis direction rigidity Kx and the Y-axis direction rigidity Ky for models with different numbers N. Asked. The results are shown in FIGS. FIG. 8 is a graph showing the relationship between the number N of the first protrusions 155 and the second protrusions 157 and the rigidity Kx in the X-axis direction. FIG. 9 is a graph showing the relationship between the number N of the first protrusions 155 and the second protrusions 157 and the rigidity Ky in the Y-axis direction.

  As can be seen from FIGS. 8 and 9, as the number N of the first protrusions 155 and the second protrusions 157 increases, the rigidity Kx in the X-axis direction decreases. However, regardless of the number N of the first protrusions 155 and the second protrusions 157, the rigidity Kx in the X-axis direction of the hinge model M1 and the rigidity Kx in the X-axis direction of the comparative model M2 are substantially the same. is there.

  As for the rigidity Ky in the Y-axis direction, the rigidity Ky in the Y-axis direction decreases as the number N of the first protrusions 155 and the second protrusions 157 increases, similarly to the rigidity Kx in the X-axis direction. However, the stiffness Ky in the Y-axis direction of the hinge model M1 is larger than the stiffness Ky in the Y-axis direction of the comparative model M2, regardless of the number N of the first projections 155 and the second projections 157.

  In this way, the first concave portions 156, 156,... Of the first meandering portion 151 and the second concave portions 158, 158,. Without increasing the rigidity Ky in the Y-axis direction. Specifically, the hinge model M1 has a shape that extends in the X-axis direction while meandering in a zigzag shape, thereby reducing the rigidity Kx in the X-axis direction. The effect of reducing the rigidity Kx in the X-axis direction is almost the same even if the first recesses 156, 156,... And the second recesses 158, 158,. On the other hand, the rigidity Ky in the Y-axis direction is increased by connecting the first recesses 156, 156,... And the second recesses 158, 158,.

  FIG. 10 shows a comparative model M2 when the tensile force Fy is applied. In the comparative model M2, the interval between the adjacent first convex portions 155 and 155, the interval between the adjacent first concave portions 156 and 156, the interval between the adjacent second convex portions 157 and 157, and the interval between the adjacent second concave portions 158 and 158. The interval has changed. In addition, the X-axis direction positions of the first recesses 156 and the corresponding second recesses 158 are shifted. Thus, the comparison model M2 is deformed. In the comparative model M2 before deformation shown in FIG. 6, the X-axis direction positions of the first recesses 156 and the corresponding second recesses 158 coincide with each other. That is, by connecting the first recesses 156, 156,... And the second recesses 158, 158,..., The first recesses 156 and the corresponding second recesses 158 may be displaced in the X-axis direction. become unable. As a result, the hinge model M1 is inhibited from being deformed in the Y-axis direction. As a result, the rigidity Ky in the Y-axis direction of the hinge model M1 increases.

-Rigidity of the first hinge and rigidity of the second hinge-
Next, the rigidity of the first hinge 105 and the second hinge 106 will be described.

  The rigidity of the second hinge 106 is larger than the rigidity of the first hinge 105. Specifically, the rigidity (spring constant) of the second hinge 106 in the X-axis direction is larger than the rigidity of the first hinge 105 in the X-axis direction. Thereby, when the mirror 131 tilts, the movable comb electrode 107 can be prevented from being displaced in the X-axis direction. That is, since the shape of the base portion 102 does not change, in order for the actuator 104 to bend and the mirror 131 to tilt, the first hinge 105 and the second hinge 106 need to extend in the X-axis direction. At this time, when the rigidity of the second hinge 106 is smaller than the rigidity of the first hinge 105, the mirror 131 is largely displaced toward the actuator 104. Then, the movable comb electrode 107 is also displaced toward the actuator 104, and the electrostatic capacitance between the movable comb electrode 107 and the fixed comb electrode 108 changes. That is, the electrostatic capacitance between the movable comb electrode 107 and the fixed comb electrode 108 changes due to a reason other than the tilt of the movable comb electrode 107 accompanying the tilt of the mirror 131. On the other hand, if the rigidity of the second hinge 106 in the X-axis direction is larger than the rigidity of the first hinge 105 in the X-axis direction, the first hinge 105 extends more than the second hinge 106. Thereby, the displacement of the mirror 131 toward the actuator 104 is suppressed. As a result, it is possible to suppress changes in capacitance due to causes other than the tilt of the movable comb electrode 107 accompanying the tilt of the mirror 131.

-Summary-
Therefore, the mirror device 100 includes a mirror 131, an actuator 104 that drives the mirror 131, and a first hinge 105 that supports the mirror 131 and is elastically deformable. The first hinges 105 are alternately arranged. A plurality of first convex portions 155 and a plurality of first concave portions 156 arranged in a zigzag shape and alternately arranged with first meander portions 151 extending from the one end portion to the other end portion while meandering. A plurality of second convex portions 157 and a plurality of second concave portions 158 are formed in a zigzag shape, are arranged in parallel with the first meandering portion 151, and extend from the one end portion to the other end portion while meandering. And at least a part of the first recesses 156 and at least a part of the second recesses 158 are connected to each other.

  In other words, the first hinge 105 is elastically deformable with the first end 153 connected to the first member and the second end 154 connected to the second member. The first hinge 105 is formed in a zigzag shape by a plurality of first convex portions 155, 155,... And a plurality of first concave portions 156, 156,. The first meandering portion 151 extending from the portion 153 to the second end 154, a plurality of second convex portions 157, 157,... And a plurality of second concave portions 158, 158,. A second meandering part 152 that extends from the first end 153 to the second end 154 while meandering, and is arranged in parallel with the first meandering part 151, and at least a part of the first recess 156. And at least a portion of the second recess 158 are connected to each other.

  According to this configuration, since the first meandering portion 151 and the second meandering portion 152 are formed in a zigzag shape and extend from one end to the other end while meandering, the direction connecting the one end and the other end, That is, the rigidity of the first hinge 105 in the X-axis direction can be made relatively small. By making the rigidity of the first hinge 105 in the X-axis direction relatively small, the first hinge 105 can be easily deformed when the mirror 131 is displaced. That is, when the mirror 131 is displaced, the first hinge 105 needs to be bent. If the rigidity of the first hinge 105 in the X-axis direction is large, the first hinge 105 becomes a resistance when the mirror 131 is displaced. On the other hand, if the rigidity of the first hinge 105 in the X-axis direction is small, the first hinge 105 easily expands and contracts in the X-axis direction. When the first hinge 105 easily expands and contracts in the X direction, the first hinge 105 is easily bent. That is, being easily stretchable in the X-axis direction contributes to the ease of bending. As a result, the mirror 131 can be easily displaced. As a result, the drive voltage of the actuator 104 can be reduced.

  In addition, by connecting at least a portion of the first recess 156 of the first meandering portion 151 and at least a portion of the second recessing portion 158 of the second meandering portion 152, the first recess 156 and the second recess 158 are formed. Compared with a configuration that can be freely displaced, the rigidity of the first hinge 105 in the direction in which the first meandering portion 151 and the second meandering portion 152 meander, that is, the Y-axis direction, can be made relatively large. By relatively increasing the rigidity of the first hinge 105 in the Y-axis direction, the mirror 131 can be prevented from colliding with surrounding members.

  Thus, in one hinge, the rigidity in the X-axis direction can be reduced and the rigidity in the Y-axis direction can be increased.

  The mirror device 100 further includes a base portion 102, and a second hinge 106 having one end connected to the mirror 131 and the other end connected to the base 102, and being elastically deformable. The first hinge 105 has one end connected to the mirror 131 and the other end connected to the actuator 104.

  According to this configuration, the first hinge 105 supports a portion of the mirror 131 on the actuator 104 side. A portion of the mirror 131 on the base portion 102 side is supported by the second hinge 106. Since the second hinge 106 is connected to the base portion 102, the portion of the mirror 131 to which the second hinge 106 is connected is not greatly displaced when the mirror 131 is driven. On the other hand, the portion of the mirror 131 to which the first hinge 105 is connected is greatly displaced according to the variation of the actuator 104. At that time, the first hinge 105 is curved. By reducing the rigidity of the first hinge 105 in the X-axis direction, the first hinge 105 can be easily bent, and the first hinge 105 can be prevented from hindering the displacement of the mirror 131. As a result, the drive voltage of the actuator 104 can be reduced.

  Further, the rigidity of the first hinge 105 in the direction in which the actuator 104 and the mirror 131 are aligned is smaller than the rigidity of the second hinge 106 in the direction.

  According to the above configuration, since the mirror 131 is supported by the first hinge 105 and the second hinge 106, it can be displaced relatively freely. Here, by relatively increasing the rigidity of the second hinge 106, the first hinge 105 extends more than the second hinge 106 when the mirror 131 is displaced. Therefore, when the mirror 131 is displaced, the distance between the mirror 131 and the base portion 102 does not change much. That is, even if the mirror 131 is configured to be relatively freely displaceable, the position of the mirror 131 can be stabilized.

  The first meandering portion 151 and the second meandering portion 152 have a line-symmetric shape.

  According to this configuration, the rigidity of the first hinge 105 can be symmetric with respect to the X axis. Thereby, it is possible to prevent the tilting axis of the mirror 131 from being tilted due to the asymmetry of the first hinge 105.

  The mirror device 100 further includes a base portion 102, a second hinge 106 that has one end connected to the mirror 131 and the other end connected to the base 102, and is elastically deformable. The rigidity of the first hinge 105 in the direction in which the mirror and the mirror are aligned is smaller than the rigidity of the second hinge 106 in the direction.

  According to this configuration, the position of the mirror 131 can be stabilized. When the mirror 131 is tilted by tilting the actuator 104, the first hinge 105 and the second hinge 106 need to extend. The position of the mirror 131 changes depending on the magnitude relationship between the extension amount of the first hinge 105 and the extension amount of the second hinge 106. Here, by making the rigidity of the first hinge 105 in the direction in which the actuator 104 and the mirror 131 are aligned, that is, in the X-axis direction smaller than that of the second hinge 106, the actuator 104 is tilted to tilt the mirror 131. In doing so, the first hinge 105 extends relatively greatly, and the second hinge 106 does not extend much. Therefore, the positional relationship between the mirror 131 and the base portion 102 can be maintained as much as possible, and the position of the mirror 131 can be stabilized.

  Further, the mirror device 100 further includes a movable comb electrode 107 coupled to the mirror 131, and a fixed comb electrode 108 fixed to the base portion 102 and facing the movable comb electrode 107, and the actuator 104. In the configuration controlled based on the electrostatic capacitance between the movable comb electrode 107 and the fixed comb electrode 108, by maintaining the positional relationship between the mirror 131 and the base portion 102 as much as possible, The positional relationship between the movable comb electrode 107 and the fixed comb electrode 108 can also be maintained. As a result, a change in capacitance between the movable comb electrode 107 and the fixed comb electrode 108 due to a cause other than the tilt of the movable comb electrode 107 accompanying the tilt of the mirror 131 can be reduced as much as possible. it can. As a result, the tilt of the mirror 131 can be controlled more accurately.

-Modification of mirror array-
Subsequently, a modification of the mirror array 1 will be described. FIG. 11 shows a plan view of the mirror array 201. The mirror array 201 according to the modification is different from the mirror device 100 in the configuration of the mirror device 200. Hereinafter, a description will be given focusing on a part of the configuration of the mirror array 201 that is different from the mirror array 1. A configuration peculiar to the modification may be described with reference numerals in the 200s. In the configuration having the same function as that of the mirror array 1, the numbers and symbols of the tens place are the same.

  The mirror array 201 includes a plurality of mirror devices 200, 200,. The mirror device 200 includes a base portion 202, a mirror 131, two actuators 204 and 204 that drive the mirror 131, two first hinges 205 and 205 that connect the mirror 131 to the actuator 204, a mirror 131, and a base portion. 202, a second movable comb electrode 207A and a second movable comb electrode 207B provided on the mirror 131, a first fixed comb electrode 208A and a second fixed comb electrode 208A provided on the base portion 202. Two fixed comb electrodes 208B and the control unit 10 are provided. The mirror device 200 drives the mirror 131 by two actuators 204 and 204. The mirror array 201 has a common control unit 10 for each of several mirror devices 200, 200,. The mirror array 201 may have one control unit 10 for each mirror device 200, or may have one control unit 10 common to all mirror devices 200, 200,.

  The basic configuration of the actuator 204 is the same as that of the actuator 104 of the first embodiment. A piezoelectric element 242 is laminated on the surface of the actuator body 241.

  The tip of the actuator body 241 is connected to the mirror 131 via the first hinge 205. The two first hinges 205 and 205 are connected to positions symmetrical to the X axis on the first short side 131a of the mirror 131, respectively. The first hinge 205 has two meandering portions arranged side by side. Each meandering part has the convex part and the recessed part which were arranged alternately. The concave portions of the two meandering portions are connected to each other. However, in one mirror device 200, two first hinges 205, 205 are provided. In the first hinge 205, the first meandering portion and the second meandering portion are provided near the mirror 131. In the other first hinge 205, the first meandering portion and the second meandering portion are provided near the actuator 204.

  The second hinge 206 has the same configuration as the first hinge 106. However, one second hinge 206 is provided in one mirror device 200. The second hinge 206 is connected to the center of the second short side 131b of the mirror 131.

  The first movable comb electrode 207A and the second movable comb electrode 207B are provided in a cantilever manner on the second short side 131b of the mirror 131 via the first arm portion 279a and the second arm portion 279b. The first arm portion 279a extends in the X-axis direction. The second arm part 279b branches off in the Y-axis direction from the middle of the first arm part 279a.

  The first movable comb electrode 207A has two first electrode fingers 271a and 271a. The first movable comb electrode 207A is located on the X axis. The first movable comb electrode 207A is farther from the mirror 131 than the second hinge 206 is. The two first electrode fingers 271a and 271a extend in the Y-axis direction in parallel with each other.

  The second movable comb electrode 207B has two second electrode fingers 271b and 271b. The second movable comb electrode 207B is arranged not on the X axis but at a position offset from the X axis in the Y axis direction. The second movable comb electrode 207B is located on the A axis. The two second electrode fingers 271b and 271b extend in the X-axis direction in parallel with each other.

  The first movable comb electrode 207A, the second movable comb electrode 207B, the first arm portion 279a, and the second arm portion 279b are formed of the first silicon layer 191. The number of the first electrode fingers 271a and the second electrode fingers 271b is not limited to two.

  On the other hand, the base portion 202 is formed with a recess 202a into which the first movable comb electrode 207A enters. A first fixed comb electrode 208A is provided in the recess 202a. The first fixed comb electrode 208A has two first electrode fingers 281a and 281a. The two first electrode fingers 281a and 281a extend in the Y-axis direction in parallel with each other. Each first electrode finger 281a enters between the first electrode fingers 271a of the first movable comb electrode 207A. That is, the first electrode finger 271a of the first movable comb electrode 207A and the first electrode finger 281a of the first fixed comb electrode 208A face each other.

  The base portion 202 is provided with a second fixed comb electrode 208B. The second fixed comb electrode 208B has two second electrode fingers 281b and 281b. The two second electrode fingers 281b and 281b extend in the X-axis direction in parallel with each other. Each second electrode finger 281b enters between the second electrode fingers 271b of the second movable comb electrode 207B. That is, the second electrode finger 271b of the second movable comb electrode 207B and the second electrode finger 281b of the second fixed comb electrode 208B are opposed to each other.

  The first fixed comb electrode 208 </ b> A and the second fixed comb electrode 208 </ b> B are formed of the first silicon layer 191. However, the first fixed comb electrode 208A and the second fixed comb electrode 208B are electrically insulated from the first movable comb electrode 207A and the second movable comb electrode 207B. Note that the number of the first electrode fingers 281a and the second electrode fingers 281b is not limited to two.

  The base portion 202 is provided with a first detection terminal 222, a second detection terminal 223, and a third detection terminal 224. The capacitances of the first movable comb electrode 207A and the first fixed comb electrode 208A can be detected through the first detection terminal 222 and the second detection terminal 223. The electrostatic capacitances of the second movable comb electrode 207B and the second fixed comb electrode 208B can be detected via the first detection terminal 222 and the third detection terminal 224.

  The first detection terminal 222 is provided on the surface of the portion of the first silicon layer 191 of the base portion 202 that is electrically connected to the first movable comb electrode 207A and the second movable comb electrode 207B.

  The second detection terminal 223 is provided on the surface of the first electrode part 225. The first electrode portion 225 is formed of the first silicon layer 191 of the base portion 202, is isolated from the surrounding portions on the oxide film layer 192 of the base portion 202, and is electrically insulated. The first electrode portion 225 is connected to the first fixed comb electrode 208A.

  The third detection terminal 224 is provided on the surface of the second electrode portion 226. The second electrode portion 226 is formed of the first silicon layer 191 of the base portion 202, is isolated from the surrounding portions on the oxide film layer 192 of the base portion 202, and is electrically insulated. The second electrode portion 226 is connected to the second fixed comb electrode 208B.

  The mirror array 201 is not provided with the reference electrode 194 unlike the mirror array 1. However, a reference electrode may be provided also in the mirror array 201.

  The mirror device 200 bends the actuator 204 upward by applying a driving voltage to the piezoelectric element 242. Thereby, the mirror 131 is tilted. At this time, the mirror 131 can be tilted around the A axis by making the bending amounts of the two actuators 204 and 204 connected to the one mirror 131 the same. On the other hand, the mirror 131 can be tilted around the X axis by making the bending amounts of the two actuators 204 and 204 different.

  When the mirror 131 tilts, the first movable comb electrode 207A and the second movable comb electrode 207B also tilt accordingly. Specifically, when the mirror 131 tilts around the A axis, the first movable comb electrode 207A is displaced vertically, and the capacitance between the first movable comb electrode 207A and the first fixed comb electrode 208A changes. To do. The electrostatic capacitance between the first movable comb electrode 207 </ b> A and the first fixed comb electrode 208 </ b> A can be detected via the first detection terminal 222 and the second detection terminal 223. By adjusting the drive voltage of the piezoelectric elements 242 and 242 based on the change in capacitance, the amount of tilting of the mirror 131 around the A axis can be accurately controlled. When the mirror 131 tilts around the X axis, the second movable comb electrode 207B is displaced up and down, and the capacitance between the second movable comb electrode 207B and the second fixed comb electrode 208B changes. . The capacitance between the second movable comb electrode 207B and the second fixed comb electrode 208B can be detected via the first detection terminal 222 and the third detection terminal 224. By adjusting the drive voltage of the piezoelectric elements 242 and 242 based on the change in capacitance, the tilt amount of the mirror 131 around the X axis can be accurately controlled.

  When the mirror 131 tilts around the A axis, the second movable comb electrode 207B is also displaced along with it, but the second movable comb electrode 207B is located on the A axis, so the second movable comb electrode The change in capacitance between 207B and the second fixed comb electrode 208B is small. That is, the electrostatic capacitance between the second movable comb electrode 207B and the second fixed comb electrode 208B changes mainly due to the tilt of the mirror 131 around the X axis, and around the A axis of the mirror 131. The effect of tilting is small. Further, when the mirror 131 tilts around the X axis, the first movable comb electrode 207A is also displaced along with it, but the first movable comb electrode 207A is located on the X axis. The change in capacitance between 207A and the first fixed comb electrode 208A is small. That is, the electrostatic capacitance between the first movable comb electrode 207A and the first fixed comb electrode 208A changes mainly due to the tilt of the mirror 131 around the A axis, The effect of tilting is small.

  Here, the first movable comb electrode 207 </ b> A is disposed closer to the second hinge 206 than the first hinge 205. That is, the first movable comb electrode 207A is provided in the vicinity of the A axis. Therefore, the amount of displacement of the first movable comb electrode 207A when the mirror 131 tilts around the A axis is suppressed. As a result, the tilting range of the mirror 131 that can detect the electrostatic capacitance between the first movable comb electrode 207A and the first fixed comb electrode 208A can be expanded. That is, the range in which the tilt amount of the mirror 131 around the A axis can be accurately controlled can be expanded. The second movable comb electrode 207B is provided in the vicinity of the X axis. Therefore, the amount of displacement of the second movable comb electrode 207B when the mirror 131 tilts around the X axis is suppressed. As a result, the tilting range of the mirror 131 that can detect the electrostatic capacitance between the second movable comb electrode 207B and the second fixed comb electrode 208B can be expanded. That is, the range in which the tilt amount of the mirror 131 around the X axis can be accurately controlled can be expanded.

-Modification of hinge-
Next, a modification of the hinge will be described. FIG. 12 is a plan view of the first hinge 305 according to the first modification. Hereinafter, the first hinge 305 will be described with a focus on portions different from the first hinge 105. The configuration of the first hinge 305 will be described with reference numerals in the 300s. In the configuration having the same function as that of the first hinge 105, the numbers and symbols of the tens place are the same.

  The first hinge 305 according to the first modification includes a meandering portion 350, first end portions 353 and 353, and second end portions 354 and 354. The meandering part 350 has a first meandering part 351 and a second meandering part 352 arranged side by side. The first meandering part 351 and the second meandering part 352 have a line-symmetric shape with respect to the X axis. The first end portions 353 and 353 are composed of one end portion of the first meandering portion 351 and one end portion of the second meandering portion 352. That is, one end portion of the first meandering portion 351 and one end portion of the second meandering portion 352 are not connected. The second end portions 354 and 354 are composed of the other end portion of the first meandering portion 351 and the other end portion of the second meandering portion 352. The other end of the first meandering portion 351 and the other end of the second meandering portion 352 are not connected. The first end portions 353 and 353 are connected to the actuator 104. The second end portions 354 and 354 are connected to the mirror 131.

  The first meandering part 351 has six first convex parts 355, 355,... And five first concave parts 356, 356,... Arranged in a zigzag shape. The first meandering portion 351 extends from the first end portion 353 to the second end portion 354 in the X-axis direction while meandering. The first convex portion 355 and the first concave portion 356 are each formed in a rectangular shape. The first convex portion 355 extends outward in the Y-axis direction, bends twice at a right angle, turns back, and extends inward in the Y-axis direction. The first recess 356 extends inward in the Y-axis direction, bends twice at a right angle, turns back, and extends outward in the Y-axis direction.

  The second meandering part 352 has six second convex parts 357, 357,... And five second concave parts 358, 358,... Arranged alternately, and is formed in a zigzag shape. The second meandering part 352 extends from the first end part 353 to the second end part 354 in the X-axis direction while meandering. The second convex portion 357 and the second concave portion 358 are each formed in a rectangular shape. The second convex portion 357 extends outward in the Y-axis direction, bends twice at a right angle, turns back, and extends inward in the Y-axis direction. The second recess 358 extends inward in the Y-axis direction, bends twice at a right angle, turns back, and extends outward in the Y-axis direction.

  Of the first recesses 356, 356,..., The second first recess 356 and the fourth first recess 356 from the first end 353 side, and the second of the second recesses 358 and 358 from the first end 353 side. The second recess 358 and the fourth second recess 358 are connected to each other. That is, the first recesses 356, 356,... And the second recesses 358, 358,.

  Even in such a configuration, the first hinge 305 can reduce the rigidity in the X-axis direction due to the presence of the first convex portion 355, the first concave portion 356, the second convex portion 357, and the second concave portion 358. . In addition, the first hinge 305 can increase the rigidity in the Y-axis direction by connecting a part of the first recesses 356 and 356 and a part of the second recesses 358 and 358.

  FIG. 13 is a plan view of the first hinge 405 according to the second modification. Hereinafter, the first hinge 405 will be described mainly with respect to a portion different from the first hinge 105. The configuration of the first hinge 405 will be described with reference numerals in the 400s. In the configuration having the same function as that of the first hinge 105, the numbers and symbols of the tens place are the same.

  The first hinge 405 according to the modification 2 includes a meandering portion 450, a first end 453, and a second end 454. The meandering part 450 has a first meandering part 451 and a second meandering part 452 arranged side by side. The first meandering part 451 and the second meandering part 452 have a line-symmetric shape with respect to the X axis. One end of the first meandering part 451 and one end of the second meandering part 452 are connected to the first end 453. The other end of the first meandering portion 451 and the other end of the second meandering portion 452 are connected to the second end 454. The first end 453 is connected to the actuator 104. The second end 454 is connected to the mirror 131.

  The first meandering portion 451 has five first convex portions 455, 455,... And four first concave portions 456, 456,... Arranged alternately, and is formed in a zigzag shape. The first meandering portion 451 extends from the first end 453 to the second end 454 in the X-axis direction while meandering. The 1st convex part 455 is formed in bell shape. The first convex portion 455 extends outward in the Y-axis direction, is folded back while being curved, and extends inward in the Y-axis direction. The first recess 456 is formed in a rectangular shape. The first recess 456 extends inward in the Y-axis direction, bends twice at a right angle, turns back, and extends outward in the Y-axis direction.

  The second meandering portion 452 has five second convex portions 457, 457,... And four second concave portions 458, 458,... Arranged alternately, and is formed in a zigzag shape. The second meandering portion 452 extends from the first end 453 to the second end 454 in the X-axis direction while meandering. The 2nd convex part 457 is formed in bell shape. The second convex portion 457 extends outward in the Y-axis direction, is folded back while being curved, and extends inward in the Y-axis direction. The second recess 458 is formed in a rectangular shape. The second recess 458 extends inward in the Y-axis direction, bends twice at a right angle, turns back, and extends outward in the Y-axis direction.

  Even in such a configuration, the first hinge 405 can reduce the rigidity in the X-axis direction due to the presence of the first convex portion 455, the first concave portion 456, the second convex portion 457, and the second concave portion 458. . In addition, the first hinge 405 can increase the rigidity in the Y-axis direction by connecting the first recesses 456, 456,... And the second recesses 458, 458,.

<< Embodiment 2 >>
Next, the mirror device 500 according to the second embodiment will be described. FIG. 14 shows a plan view of the mirror device 500. In the following, description will be made centering on differences from the first embodiment in the configuration of the mirror device 500. The configuration of the second embodiment will be described with reference numerals in the 500s. In the configuration having the same function as that of the first embodiment, the numbers and symbols of the tens place are the same.

  The mirror device 500 is used, for example, as a variable optical attenuator (VOA). The mirror device 500 includes a base portion 502, a mirror 531, actuators 504 and 504 that drive the mirror 531, a first hinge 505 that connects the mirror 531 and the actuators 504 and 504, a mirror 531, and the base portion 502. It has the 2nd hinges 506 and 506 to connect, the movable comb electrode 507 provided in the mirror 531, the fixed comb electrode 508 provided in the base part 502, and a control part (illustration omitted).

  The base portion 502 is formed in a frame shape having a circular opening.

  The mirror 531 is formed in a circular plate shape in plan view. The mirror 531 is located in the circular opening of the base portion 502. An annular space S is formed between the base portion 502 and the mirror 531.

  The mirror 531 is connected to the base portion 502 via two second hinges 506 and 506. A first hinge 505 is provided on a part of the mirror 531 opposite to the second hinges 506 and 506. The first hinge 505 has two meandering portions arranged side by side. Each meandering part has the convex part and the recessed part which were arranged alternately. The concave portions of the two meandering portions are connected to each other. The second hinge 506 is bent in a zigzag shape as a whole.

  The actuator 504 includes an actuator main body 541 and a piezoelectric element 542 stacked on the surface of the actuator main body 541. The actuator body 541 extends in a substantially arc shape along an annular space S between the mirror 531 and the base portion 502. One actuator body 541 is provided between the first hinge 505 and one second hinge 506. The other actuator body 541 is provided between the first hinge 505 and the other second hinge 506. One end of the actuator body 541 is connected to the base portion 502 in the vicinity of the second hinge 506. The other end of the actuator body 541 is connected to the first hinge 505. The piezoelectric element 542 is formed in a substantially arc shape like the actuator body 541.

  The actuators 504 and 504 and the second hinges 506 and 506 are symmetrical with respect to the X axis passing through the center of the mirror 531 and the first hinge 505.

  The movable comb electrode 507 is provided at the tip of an arm portion 579 extending radially outward from the mirror 531. The arm portion 579 is provided between the two second hinges 506 and 506. More specifically, the arm portion 579 is located on the X axis. The movable comb electrode 507 has three electrode fingers 571, 571,. Each electrode finger 571 extends from the arm portion 579 to both sides so as to be orthogonal to the arm portion 579. The three electrode fingers 571, 571,... Extend in parallel to each other and in a direction perpendicular to the X axis. The number of electrode fingers 571 is not limited to three.

  The fixed comb electrode 508 is provided on the base portion 502. The fixed comb electrode 508 has four electrode fingers 581, 581,. The four electrode fingers 581, 581,... Extend in a direction parallel to each other and perpendicular to the X axis. Each electrode finger 581 enters between the electrode fingers 571 of the movable comb electrode 507. That is, the electrode finger 571 of the movable comb electrode 507 and the electrode finger 581 of the fixed comb electrode 508 are opposed to each other. However, the fixed comb electrode 508 is electrically insulated from the movable comb electrode 507.

  The movable comb electrode 507 and the fixed comb electrode 508 are arranged on the X axis.

  Although not shown, the base unit 502 is provided with a detection terminal for detecting the electrostatic capacitance of the movable comb electrode 507 and the fixed comb electrode 508.

  As in the first embodiment, a reference electrode having a first electrode finger corresponding to the electrode finger 571 of the movable comb electrode 507 and a second electrode finger corresponding to the electrode finger 581 of the fixed comb electrode 508 is provided. Also good.

  Next, the operation of the mirror device 500 configured as described above will be described. When the control unit of the mirror device 500 applies a voltage to the piezoelectric elements 542 and 542, each actuator 504 is bent with the piezoelectric element 542 inside, and the end of the actuator 504 on the first hinge 505 side is displaced upward. The same voltage is applied to the piezoelectric elements 542 and 542 of the two actuators 504 and 504. As a result, the mirror 531 tilts about the second hinges 506 and 506. That is, the mirror 531 tilts around the A axis that is orthogonal to the X axis and substantially passes through the second hinges 506 and 506.

  When the mirror 531 tilts, the movable comb electrode 507 is also displaced accordingly. As a result, the area of the portion where the electrode finger 571 of the movable comb electrode 507 and the electrode finger 581 of the fixed comb electrode 508 face each other changes, and the area between the movable comb electrode 507 and the fixed comb electrode 508 changes. The capacitance changes. The control unit detects the capacitance between the movable comb electrode 507 and the fixed comb electrode 508 via the detection terminal, and adjusts the voltage applied to the piezoelectric elements 542 and 542 based on the change in the capacitance. To do. Thereby, the control unit controls the tilt amount of the mirror 531 with high accuracy.

  Here, the movable comb electrode 507 is provided closer to the second hinge 506 than the first hinge 505. That is, the movable comb electrode 507 is located in the vicinity of the A axis that becomes the center when the mirror 531 tilts. Therefore, the displacement amount of the movable comb electrode 507 when the mirror 531 tilts around the A axis is suppressed. As a result, the tilting range of the mirror 531 that can detect the electrostatic capacitance between the movable comb electrode 507 and the fixed comb electrode 508 can be expanded. That is, the range in which the tilt amount of the mirror 531 around the A axis can be accurately controlled can be expanded.

  In addition, since the actuator 504 is disposed using the annular space S, the actuator 504 is formed in a substantially arc shape, but is not limited thereto. The actuator 504 may be formed in a rectangular shape as in the first embodiment. In that case, as in the first embodiment, the actuator 504, the first hinge 505, and the mirror 531 may be arranged in a substantially straight line in this order.

-Modification of mirror device-
Subsequently, a mirror device 600 according to a modification will be described. FIG. 15 is a plan view of a mirror device 600 according to a modification. Hereinafter, a description will be given focusing on a part of the configuration of the mirror device 600 that is different from the mirror device 500. A configuration peculiar to the modified example may be described with a reference numeral 600. In the configuration having the same function as that of the mirror device 500, the numbers and symbols of the tens place are the same.

  The mirror device 600 includes a base portion 602, a mirror 531, actuators 604 and 604 that drive the mirror 531, first hinges 605 and 605 that connect the mirror 531 and actuators 604 and 604, a mirror 531, and a base portion 602. , A first movable comb electrode 607A and a second movable comb electrode 607B provided on the mirror 531, a first fixed comb electrode 608A and a second fixed comb electrode 608B provided on the base portion 602. It has a fixed comb electrode 608B and a control unit (not shown).

  The base portion 602 is formed in a frame shape having a circular opening.

  The mirror 531 has the same configuration as the mirror 531 of the mirror device 500. It is connected to the base portion 602 through one second hinge 606. The second hinge 606 is bent in a zigzag manner as a whole.

  The actuator 604 has an actuator body 641 and a piezoelectric element 642 stacked on the surface of the actuator body 641. One actuator 604 is arranged in one space when the annular space S between the mirror 531 and the base portion 602 is divided into two by the center of the mirror 531 and the X axis passing through the second hinge 606, and the other The other actuator 604 is disposed in this space. The actuator body 641 extends in a substantially arc shape along the space. One end of each actuator body 641 is connected to the base portion 602 in the vicinity of the second hinge 606. The other end of each actuator body 641 is connected to the mirror 531 via the first hinge 605. The piezoelectric element 642 is formed in a substantially arc shape like the actuator body 641.

  The first hinge 605 has two meandering portions arranged side by side. Each meandering part has the convex part and the recessed part which were arranged alternately. The concave portions of the two meandering portions are connected to each other.

  The actuators 604 and 604 and the first hinges 605 and 605 are symmetrical with respect to the X axis.

  The first movable comb electrode 607A is provided at the tip of the first arm portion 679a extending from the mirror 531 in the vicinity of the second hinge 606. The first arm portion 679a is provided in the vicinity of the second hinge 606 on the outer periphery of the mirror 531 and at a position offset from the X axis. The first arm portion 679a extends in parallel with the X axis from the mirror 531, then bends at a right angle toward the X axis, and bends at a right angle in the X axis direction when reaching the X axis. That is, the distal end portion of the first arm portion 679a extends on the X axis. The first movable comb electrode 607A has three first electrode fingers 671a, 671a,. Each first electrode finger 671a extends from the distal end portion of the first arm portion 679a to both sides so as to be orthogonal to the distal end portion of the first arm portion 679a. The three first electrode fingers 671a, 671a,... Extend in parallel to each other and in a direction perpendicular to the X axis.

  The second movable comb electrode 607B is provided at the tip of the second arm portion 679b extending from the mirror 531 in the vicinity of the second hinge 606. The second arm portion 679b extends in parallel to the X axis from the mirror 531 in the vicinity of the second hinge 606, and then bends at a right angle and extends in a direction perpendicular to the X axis. The second movable comb electrode 607B has three second electrode fingers 671b, 671b,. Each second electrode finger 671b extends from the distal end portion of the second arm portion 679b to both sides so as to be orthogonal to the distal end portion of the second arm portion 679b. Three second electrode fingers 671b, 671b,... Extend in parallel to each other and in the X-axis direction.

  Note that the number of the first electrode fingers 671a and the second electrode fingers 671b is not limited to three.

  The first fixed comb electrode 608 </ b> A is provided on the base portion 602. The first fixed comb electrode 608A has four first electrode fingers 681a, 681a,. The four first electrode fingers 681a, 681a,... Extend in parallel to each other and in a direction perpendicular to the X axis. Each first electrode finger 681a penetrates between the first electrode fingers 671a of the first movable comb electrode 607A. That is, the first electrode finger 671a of the first movable comb electrode 607A and the first electrode finger 681a of the first fixed comb electrode 608A face each other. However, the first fixed comb electrode 608A is electrically insulated from the first movable comb electrode 607A.

  The second fixed comb electrode 608 </ b> B is provided on the base portion 602. The second fixed comb electrode 608B has four second electrode fingers 681b, 681b,. The four second electrode fingers 681b, 681b,... Extend in the X-axis direction in parallel with each other. Each second electrode finger 681b enters between the second electrode fingers 671b of the second movable comb electrode 607B. That is, the second electrode finger 671b of the second movable comb electrode 607B and the second electrode finger 681b of the second fixed comb electrode 608B are opposed to each other. However, the second fixed comb electrode 608B is electrically insulated from the second movable comb electrode 607B.

  The first movable comb electrode 607A and the first fixed comb electrode 608A are arranged on the X axis. The second movable comb electrode 607B and the second fixed comb electrode 608B are disposed on the A axis that is orthogonal to the X axis and substantially passes through the second hinge 606.

  Although illustration is omitted, the base portion 602 includes capacitances of the first movable comb electrode 607A and the first fixed comb electrode 608A and the second movable comb electrode 607B and the second fixed comb electrode 608B. A detection terminal for detecting the capacitance is provided.

  Next, the operation of the mirror device 600 configured as described above will be described. When the control unit of the mirror device 600 applies a voltage to the piezoelectric elements 642 and 642, each actuator 604 is bent with the piezoelectric element 642 inside, and the end of the actuator 604 on the first hinge 605 side is displaced upward. When the same voltage is applied to the piezoelectric elements 642 and 642 of the two actuators 604 and 604, the mirror 531 tilts around the second hinge 606. That is, the mirror 531 tilts around the A axis. On the other hand, when different voltages are applied to the piezoelectric elements 642 and 642 of the two actuators 604 and 604, the mirror 531 tilts around the X axis.

  When the mirror 531 tilts, the first movable comb electrode 607A and the second movable comb electrode 607B are also displaced accordingly. As a result, the area of the portion of the first movable comb electrode 607A facing the first electrode finger 671a and the first electrode finger 681a of the first fixed comb electrode 608A changes, and the first movable comb electrode 607A. And the first fixed comb electrode 608A change in capacitance. Further, the area of the portion of the second movable comb electrode 607B facing the second electrode finger 671b and the second electrode finger 681b of the second fixed comb electrode 608B changes, and the second movable comb electrode 607B The capacitance between the second fixed comb electrode 608B changes. The control unit sets the capacitance between the first movable comb electrode 607A and the first fixed comb electrode 608A and the capacitance between the second movable comb electrode 607B and the second fixed comb electrode 608B. It detects via a detection terminal and adjusts the applied voltage of piezoelectric element 642,642 based on the change of this electrostatic capacitance. Thereby, the control unit controls the tilt amount of the mirror 531 with high accuracy.

  Here, the first movable comb electrode 607 </ b> A is provided closer to the second hinge 606 than to the first hinge 605. That is, the first movable comb electrode 607A is located in the vicinity of the A axis. Therefore, the displacement amount of the first movable comb electrode 607A when the mirror 531 tilts around the A axis is suppressed. As a result, the tilting range of the mirror 531 capable of detecting the electrostatic capacitance between the first movable comb electrode 607A and the first fixed comb electrode 608A can be expanded. That is, the range in which the tilt amount of the mirror 531 around the A axis can be accurately controlled can be expanded. The second movable comb electrode 607B is provided in the vicinity of the X axis. Therefore, the displacement amount of the second movable comb electrode 607B when the mirror 531 tilts around the X axis is suppressed. As a result, the tilting range of the mirror 531 capable of detecting the capacitance between the second movable comb electrode 607B and the second fixed comb electrode 608B can be expanded. That is, the range in which the tilt amount of the mirror 531 around the X axis can be accurately controlled can be expanded.

<< Other Embodiments >>
As described above, the embodiment has been described as an example of the technique disclosed in the present application. However, the technology in the present disclosure is not limited to this, and can also be applied to an embodiment in which changes, replacements, additions, omissions, and the like are appropriately performed. Moreover, it is also possible to combine each component demonstrated by the said embodiment and it can also be set as new embodiment. In addition, among the components described in the accompanying drawings and detailed description, not only the components essential for solving the problem, but also the components not essential for solving the problem in order to exemplify the above technique. May also be included. Therefore, it should not be immediately recognized that these non-essential components are essential as those non-essential components are described in the accompanying drawings and detailed description.

  About the said embodiment, it is good also as following structures.

  In the first embodiment, a mirror array including a plurality of mirror devices has been described. However, the present invention is not limited to this. An apparatus constituted by one mirror device, such as a galvanometer mirror, may be used. For example, the VOA may be configured using the mirror device of the first embodiment. Further, the mirror array is not limited to being applied to a wavelength selective switch, and can be incorporated into various applications.

  In the second embodiment, one mirror device has been described. However, a mirror array may be configured by arranging a plurality of mirror devices.

  Moreover, the shape, dimension, and material in the said embodiment are only illustrations, and are not restricted to these. For example, the mirror 131 does not have to be rectangular in plan view. The mirror 131 may be circular or oval. The mirror 531 may not be circular in plan view. The mirror 531 may be oval or rectangular. The shape and number of the first hinges 105, 205, 305, 405, 505, and 605 are not limited to the above configuration. The shape and number of the second hinges 106, 206, 506, and 606 are not limited to the above configuration.

  The second hinges 106, 206, 506, and 606 have two meandering portions in which convex portions and concave portions are alternately arranged, like the first hinges 105, 205, 305, 405, 505, and 605, The structure by which the recessed parts of two meandering parts were connected may be sufficient. In that case, the first hinges 105, 205, 305, 405, 505, and 605 have two meandering portions in which convex portions and concave portions are alternately arranged, and the concave portions of the two meandering portions are connected to each other. Instead, other shapes may be used.

  Further, the configurations of the movable comb electrodes 107, 207A, 207B, 507, 607A, 607B and the fixed comb electrodes 108, 208A, 208B, 508, 608A, 608B are examples, and other configurations are possible. Also good. For example, the movable comb electrodes 107, 207 A, and 207 B may be provided on an arm portion extending from the long side of the mirror 131. Further, the movable comb electrode 107 may be provided at a position aligned with the second hinge 206 in the Y-axis direction, like the second movable comb electrode 207B. Furthermore, the electrode fingers of the movable comb electrodes 107 and 207B extend in the X-axis direction, but may extend in the Y-axis direction, for example. Similarly, the electrode fingers of the movable comb electrode 207A extend in the Y-axis direction, but may extend in the X-axis direction, for example. The positions of the movable comb electrodes 507, 607A, and 607B and the fixed comb electrodes 508, 608A, and 608B and the extending direction of the electrode fingers can be arbitrarily set.

The piezoelectric element may use, as a piezoelectric layer, KNN ((K, Na) NbO ₃ ), which is a lead-free piezoelectric material, instead of PZT.

  The actuator includes a piezoelectric element, but is not limited thereto. For example, an actuator that drives a mirror using electrostatic attraction may be used.

  In addition, the above embodiment is an essentially preferable illustration, Comprising: It does not intend restrict | limiting the range of this invention, its application thing, or its use.

  As described above, the technique disclosed herein is useful for mirror devices.

100, 200, 500, 600 Mirror device 131, 531 Mirror 104, 204, 504, 604 Actuator 105, 205, 305, 405, 505, 605 First hinge 151, 351, 451 First meander 155, 355, 455 First 1 convex part 156,356,456 1st recessed part 152,352,452 2nd meander part 157,357,457 2nd convex part 158,358,458 2nd recessed part 106,206,506,606 2nd hinge 141,241 , 541, 641 Actuator body 142, 242, 542, 642 Piezoelectric element 107, 507 Movable comb electrode 207A, 607A First movable comb electrode 207B, 607B Second movable comb electrode 108, 508 Fixed comb electrode 208A, 608A First fixed comb electrode 208B, 608B Second fixed Comb electrode

Claims (6)

Mirror,
An actuator for driving the mirror;
A first hinge that supports the mirror and is elastically deformable;
The first hinge is
A first serpentine portion formed in a zigzag shape by a plurality of first convex portions and a plurality of first concave portions arranged alternately, and extending from the one end portion to the other end portion while meandering;
A plurality of second convex portions and a plurality of second concave portions arranged alternately are formed in a zigzag shape, are arranged in parallel with the first meandering portion, and extend from the one end portion to the other end portion while meandering. A meandering portion,
At least a part of the first recesses and at least a part of the second recesses are mirror devices connected to each other. The mirror device according to claim 1,
A base part;
A second hinge having one end connected to the mirror and the other end connected to the base and elastically deformable;
The first hinge is a mirror device having one end connected to the mirror and the other end connected to the actuator. The mirror device according to claim 2,
The rigidity of the first hinge in the direction in which the actuator and the mirror are aligned is smaller than the rigidity of the second hinge in the direction. The mirror device according to any one of claims 1 to 3,
The first meandering portion and the second meandering portion are mirror devices having a line-symmetric shape. One end is connected to the first member, the other end is connected to the second member, and is an elastically deformable hinge,
A first serpentine portion formed in a zigzag shape by a plurality of first convex portions and a plurality of first concave portions arranged alternately, and extending from the one end portion to the other end portion while meandering;
A plurality of second convex portions and a plurality of second concave portions arranged alternately are formed in a zigzag shape, are arranged in parallel with the first meandering portion, and extend from the one end portion to the other end portion while meandering. With meandering section,
A hinge in which at least a part of the first recess and at least a part of the second recess are connected to each other. The hinge according to claim 5,
The first meandering portion and the second meandering portion are hinges having a line-symmetric shape.

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