Optical reflection element

Abstract

An optical reflection element (1) includes a movable part (40) provided with a reflection surface; and a pair of drive parts (20) that are disposed so as to sandwich the movable part (40) in parallel with a rotation axis (R10) and that rotate the movable part (40) around the rotation axis (R10). Each of the drive parts (20) includes: a vibration plate (21) in which ends of a plurality of vibration units (101) extending in a direction substantially orthogonal to the rotation axis (R10) in plan view are connected, in a meandering manner, by a plurality of connection units (112) extending in a direction substantially parallel to the rotation axis (R10); and a rib (122) disposed in each of the connection units (112). Gaps (G2, G5, G8), which are larger than a gap (G1) between adjacent vibration units (101), are present on the movable part (40) side of each rib (122).

Description

Optical Reflective Elements

[0001] The present invention relates to an optical reflecting element having a movable portion on which a reflecting surface is formed.

[0002] An optical reflecting element having a movable part on which a reflective surface is formed is known. In this type of optical reflecting element, for example, the reflective surface is disposed on a movable part that rotates about a rotation axis, and a beam incident on the reflective surface is scanned as the movable part rotates.

[0003] The following Patent Document 1 describes an optical deflector equipped with a meander-shaped actuator (drive unit). The actuator includes a plurality of piezoelectric cantilevers arranged in parallel at intervals, a connecting portion connecting the ends of adjacent piezoelectric cantilevers on the same side, and a rib provided on the inside (piezoelectric cantilever side) of the connecting portion. The rib is arranged over a range in the width direction of the two piezoelectric cantilevers connected by the connecting portion that is wider than the range of the gap between the two piezoelectric cantilevers. By providing the rib on the connecting portion, deformation of the connecting portion is reduced, and the swing angle of the mirror unit around the axis caused by the actuator is increased.

[0004] JP 2014-235298 A

[0005] In the optical reflecting element described in Patent Document 1, the thickness of the portion where the ribs are formed is greater than the thickness of the other portions. Therefore, when forming a meander shape by an etching process, the distance between adjacent ribs becomes greater than the processing limit width of these ribs. As a result, if adjacent ribs extend to the end of the connecting portion, the distance between adjacent cantilevers cannot be made smaller than the processing limit width of the ribs, and as a result, the size of the optical reflecting element becomes large.

[0006] In view of the above problem, an object of the present invention is to provide an optical reflecting element that can be reduced in size.

[0007] The optical reflecting element according to a main aspect of the present invention includes a movable part provided with a reflective surface, and a pair of drive parts arranged parallel to a rotation axis so as to sandwich the movable part and rotate the movable part about the rotation axis. Each of the drive parts includes a vibration plate in which ends of a plurality of vibration parts extending in a direction substantially perpendicular to the rotation axis in a plan view are connected in a meandering shape by a plurality of connecting parts extending in a direction substantially parallel to the rotation axis, and a rib arranged on each of the connecting parts. A gap larger than the gap between adjacent vibration parts exists on the movable part side of each of the ribs.

[0008] In the optical reflecting element according to this aspect, since there is a gap on the movable part side of the rib that is larger than the gap between adjacent vibrating parts, in the etching process, the gap between adjacent vibrating parts can be made smaller than the processing limit width of the rib, thereby making it possible to reduce the size of the optical reflecting element in the direction parallel to the rotation axis.

[0009] As described above, according to the present invention, it is possible to provide an optical reflecting element that can be reduced in size.

[0010] The effects and significance of the present invention will become more apparent from the following description of the embodiments, however, the embodiments shown below are merely examples of how the present invention can be implemented, and the present invention is not limited to the embodiments described below.

[0011] FIG. 1 is a schematic plan view of the configuration of an optical reflecting element according to an embodiment, as seen from the front side. FIG. 2 is a schematic bottom view of the configuration of an optical reflecting element according to an embodiment, as seen from the back side. FIG. 3 is a schematic side view of the C1-C2 cross section of FIG. 2 according to an embodiment. FIG. 4 is a schematic bottom view of gaps between vibration units and gaps between ribs according to an embodiment. FIG. 5 is a schematic bottom view of the vicinity of the end of the X-axis negative side drive unit on the Y-axis positive side according to an embodiment. FIG. 6 is a schematic bottom view of the configuration of an optical reflecting element according to Modification Example 1, as seen from the back side. FIG. 7 is a schematic bottom view of the vicinity of the Y-axis positive side end of the X-axis negative side drive unit according to Modification Example 1. FIG. 8 is a schematic bottom view of the configuration of an optical reflecting element according to Modification Example 2, as seen from the back side. FIG. 9 is a schematic bottom view of the vicinity of the Y-axis positive side end of the X-axis negative side drive unit according to Modification Example 2. FIG. 10 is a bottom view schematically showing the configuration of an optical reflecting element according to Modification Example 3, as viewed from the back surface side. FIG. 11 is a bottom view schematically showing the vicinity of the end of the drive section on the negative side of the X axis on the positive side of the Y axis, as viewed from the back surface side, as viewed from the back surface side, according to Modification Example 3. FIG. 12 is a bottom view schematically showing the configuration of an optical reflecting element according to Modification Example 4, as viewed from the back surface side. FIG. 13 is a bottom view schematically showing the vicinity of the end of the drive section on the negative side of the X axis on the positive side of the Y axis, as viewed from the back surface side, according to Modification Example 4. FIG. 14 is a bottom view schematically showing the configuration of an optical reflecting element according to Modification Example 5, as viewed from the back surface side. FIG. 15 is a bottom view schematically showing the vicinity of the end of the drive section on the negative side of the X axis on the positive side of the Y axis, as viewed from the back surface side, according to Modification Example 5. FIG. 16 is a bottom view schematically showing the configuration of an optical reflecting element according to Modification Example 6, as viewed from the back surface side.

[0012] However, the drawings are for illustrative purposes only and do not limit the scope of the present invention.

[0013] Hereinafter, embodiments of the present invention will be described with reference to the drawings. For convenience, each drawing is labeled with X, Y, and Z axes that are orthogonal to each other. The positive direction of the Z axis is the vertically upward direction.

[0014] FIG. 1 is a schematic plan view of the configuration of an optical reflecting element 1 as viewed from the front surface side (in the negative direction of the Z axis).

[0015] The optical reflecting element 1 includes a fixed portion 10, a pair of drive portions 20, a pair of connecting beams 30, and a movable portion 40. The optical reflecting element 1 is configured to be point-symmetrical with respect to a center C10 in a plan view. Hereinafter, "inside" refers to the side closer to the center C10, and "outside" refers to the side farther from the center C10. The optical reflecting element 1 is formed by processing an SOI wafer, and each portion of the optical reflecting element 1 is integrally connected by an active layer 201, which will be described later.

[0016] The fixed part 10 is configured in a frame shape. In a plan view, the pair of drive parts 20 and the pair of connecting beams 30 are located in an opening 11 that penetrates the fixed part 10 in the Z-axis direction at the center of the fixed part 10, and are disposed between the fixed part 10 and the movable part 40. A pair of drive parts 20 and connecting beams 30 is disposed on each of the positive and negative sides of the X-axis of the movable part 40.

[0017] Movable portion 40 has a circular outline in a plan view. Movable portion 40 is supported by fixed portion 10 so as to be rotatable about rotation axis R10 via a pair of drive portions 20 and a pair of connecting beams 30. The center of movable portion 40 coincides with the position of center C10 of optical reflecting element 1.

[0018] The upper surface of the movable part 40 (the upper surface of the active layer 201 described later) is a reflective surface 40a that reflects light. Typically, the upper surface of the active layer 201 has sufficient reflectivity due to the generation of an SOI wafer, so the upper surface of the active layer 201 can be used as the reflective surface 40a. The reflectivity of the reflective surface 40a may be increased by polishing the upper surface of the active layer 201 of the movable part 40. Alternatively, an optical reflective film may be separately formed on the upper surface of the active layer 201 of the movable part 40, and the upper surface of the optical reflective film may be used as the reflective surface 40a.

[0019] The driving section 20 includes a vibration plate 21 having a meandering shape in a plan view, and four piezoelectric elements 22 .

[0020] The diaphragm 21 includes four vibration parts 101, one connection part 111, three linking parts 112, and one connection part 113. All four vibration parts 101 extend in a direction perpendicular to the rotation axis R10 (Y-axis direction) and are arranged side by side with a predetermined gap between them. The connection part 111 connects the fixed part 10 and an end of the outermost vibration part 101. The linking part 112 connects the ends of two adjacent vibration parts 101. The connection part 113 connects the end of the innermost vibration part 101 and the connecting beam 30.

[0021] The linking portion 112 and the connecting portions 111, 113 have a rectangular shape extending in the direction of the rotation axis R10 (X-axis direction) in a plan view. This allows the linking portion 112 to firmly connect two adjacent vibrating portions 101, the connecting portion 111 to firmly connect the fixed portion 10 and the outermost vibrating portion 101, and the connecting portion 113 to firmly connect the innermost vibrating portion 101 and the connecting beam 30.

[0022] The position of the inner end of the connecting portion 111 in the X-axis direction coincides with the position of the inner end of the outermost vibrating portion 101 in the X-axis direction. The positions of both ends of the linking portion 112 in the X-axis direction coincide with the positions of the inner and outer ends in the X-axis direction of the two vibrating portions 101 connected by the linking portion 112. The position of the outer end of the connecting portion 113 in the X-axis direction coincides with the position of the outer end of the innermost vibrating portion 101 in the X-axis direction.

[0023] The piezoelectric bodies 22 are formed on the upper surfaces of the eight vibrating members 101 provided in the pair of driving units 20. The piezoelectric bodies 22 are so-called piezoelectric transducers. Piezoelectric transducers are also called piezoelectric actuators. The piezoelectric bodies 22 have a layer structure consisting of a lower electrode layer 211, a piezoelectric layer 212, and an upper electrode layer 213, which will be described later. When a driving voltage is applied to the piezoelectric bodies 22, the piezoelectric layer 212 within the piezoelectric bodies 22 deforms due to the inverse piezoelectric effect, causing the vibrating members 101 in which the piezoelectric bodies 22 are formed to vibrate so as to bend. The piezoelectric bodies 22 are connected to electrodes on the fixed unit 10 via wiring on the vibrating members 101, the connecting members 111, and the linking members 112. For example, a cable (external wiring) connected to an external device is connected to the electrodes on the fixed unit 10 by wire bonding.

[0024] Of the four vibration portions 101 of one vibration plate 21, a first drive voltage of the same phase is applied to the piezoelectric bodies 22 on the first and third vibration portions 101 from the outside, and a second drive voltage of the same phase is applied to the piezoelectric bodies 22 on the second and fourth vibration portions 101 from the outside. At this time, the first drive voltage and the second drive voltage are opposite in phase to each other. As a result, the meandering vibration plate 21 rotates about the rotation axis R10, and the movable portion 40 supported by the pair of vibration plates 21 rotates about the rotation axis R10.

[0025] FIG. 2 is a bottom view schematically showing the configuration of optical reflecting element 1 as viewed from the rear surface side (positive direction of the Z axis).

[0026] In Fig. 2, ribs formed on the back surface (negative side of the Z axis) of optical reflecting element 1 so as to protrude in the negative Z direction are shown by dots for convenience. As will be described later, the ribs of optical reflecting element 1 are composed of intermediate oxide film 202 and base layer 203. That is, in Fig. 2, optical reflecting element 1 is composed of active layer 201, intermediate oxide film 202, and base layer 203 in the dotted areas, and is composed of only active layer 201 in the areas other than the dotted areas. Piezoelectric body 22 shown in Fig. 1 is formed on the front surface side of vibrating section 101.

[0027] A rib 12 is formed on the back surface of the fixed portion 10. One rib 121, three ribs 122, and one rib 123 are formed on the back surface of one vibration plate 21. The rib 121 is formed on the back surface of the connection portion 111, the rib 122 is formed on the back surface of the linking portion 112, and the rib 123 is formed on the back surface of the connection portion 113. A rib 31 is formed on the back surface of the connection beam 30. A rib 41 having a circular ring shape in a plan view is formed on the back surface of the movable portion 40. The ribs 12 and 121 are integrally formed, and the ribs 123, 31, and 41 are integrally formed.

[0028] FIG. 3 is a side view schematically showing a cross section taken along the line C1-C2 of FIG.

[0029] The optical reflecting element 1 is formed by processing a single SOI wafer in which an active layer 201, an intermediate oxide film 202, and a base layer 203 are stacked in the negative direction of the Z axis. The active layer 201 and the base layer 203 are made of, for example, silicon (Si), and the intermediate oxide film 202 is made of, for example, silicon dioxide (SiO ２ ) is composed of

[0030] First, a lower electrode layer 211, a piezoelectric layer 212, and an upper electrode layer 213 are stacked in the positive direction of the Z axis on the upper surface of the SOI wafer. Then, the lower electrode layer 211, the piezoelectric layer 212, and the upper electrode layer 213 are processed by etching so that the piezoelectric body 22 is formed on the upper surface of the vibration section 101. After that, the active layer 201 is processed, and the intermediate oxide film 202 and the base layer 203 are processed in this order. The active layer 201 is processed by etching from the upper side (positive side of the Z axis), and the intermediate oxide film 202 and the base layer 203 are processed by etching from the lower side (negative side of the Z axis). The thickness of the rib (the sum of the thicknesses of the intermediate oxide film 202 and the base layer 203) is greater than the thickness of the active layer 201.

[0031] The fixed portion 10, the vibrating portion 101, and the connecting portion 112 are formed of an active layer 201. The ribs 12 and 122 are formed of an intermediate oxide film 202 and a base layer 203. In addition, the connecting portions 111 and 113 are also formed of the active layer 201. The ribs 121, 123, 31, and 41 are also formed of the intermediate oxide film 202 and the base layer 203.

[0032] When processing active layer 201, etching is performed from the upper side of the SOI wafer, and active layer 201 in each part of optical reflecting element 1 is simultaneously processed. When processing intermediate oxide film 202 and base layer 203, etching is performed from the lower side of the SOI wafer, and intermediate oxide film 202 and base layer 203 in each part of optical reflecting element 1 are simultaneously processed.

[0033] Here, the thickness of active layer 201 is sufficiently small, so the processing limit width of active layer 201 can also be sufficiently small. However, the thickness of the rib (the total thickness of intermediate oxide film 202 and base layer 203) is several times larger than the thickness of active layer 201, so the processing limit width of the rib is larger than the processing limit width of active layer 201. For this reason, for example, when the position of the end of diaphragm 21 is to be aligned with the position of the end of the rib provided on the back surface of diaphragm 21, the spacing between vibrating parts 101 cannot be made smaller than the processing limit width of the rib, resulting in a problem of an increase in the size of the optical reflecting element.

[0034] In contrast to this, in this embodiment, the gap between adjacent ribs is larger than the gap between adjacent vibration parts 101. This allows the gap between adjacent vibration parts 101 to be made smaller than the processing limit width of the rib in the etching process, thereby making it possible to reduce the size of optical reflecting element 1.

[0035] FIG. 4 is a bottom view that schematically shows the gap G1 between the vibrating portions 101 and the gaps G2 to G10 between the ribs.

[0036] The gap G1 between two adjacent vibrating parts 101 is set to, for example, the processing limit width of the active layer 201. Therefore, the gap between adjacent connecting parts 111 and linking parts 112 is also G1, the gap between two adjacent linking parts 112 is also G1, and the gap between adjacent linking parts 112 and connecting parts 113 is also G1. In addition, the gap between the outermost vibrating part 101 and linking part 112 and the fixed part 10 facing them is also G1.

[0037] The gap G2 between two adjacent ribs 122 is set, for example, to be equal to or greater than the processing limit width of the ribs (intermediate oxide film 202 and base layer 203). Similarly, the gap G3 between the outermost rib 122 and the rib 12 of the fixed part 10 facing the rib 122 in the X-axis direction, the gap G4 between adjacent ribs 121 and 122, and the gap G5 between adjacent ribs 122 and 123 are also set, for example, to be equal to or greater than the processing limit width of the ribs. In this embodiment, the gaps G2 to G5 are all set to the processing limit width of the ribs.

[0038] Furthermore, a gap G6 between the rib 31 of the connecting beam 30 and the rib 41 of the movable portion 40 is equal to or larger than the gaps G2 to G5. A radial gap G7 on the inner side of the rib 41 is several times larger than the gaps G2 to G5. A gap G8 between the rib 31 of the connecting beam 30 of one drive portion 20 and the rib 122 of the connecting portion 112 of the other drive portion 20 is several times larger than the gaps G2 to G5. A gap G9 between the rib 31 of the connecting beam 30 and the rib 12 of the fixed portion 10 is several times larger than the gaps G2 to G5. A gap G10 between the ribs 12 facing each other across the opening 11 of the fixed portion 10 is several times larger than the gaps G2 to G5.

[0039] Thus, if there is variation in the gaps between adjacent ribs, when attempting to form ribs by etching the SOI wafer from the underside, the processing limit width of the rib becomes larger than the processing limit width of the active layer 201. In contrast, in this embodiment, gaps G2 to G5 are set at the processing limit width of the active layer 201 as described above, and as shown in FIG. 4 , regions where ribs are not formed are provided on the back side of the linking portion 112 and the connecting portion 113. In this embodiment, because ribs are not formed in these regions, two vibrating portions 101 adjacent in the X-axis direction can be arranged with a gap G1 narrower than the processing limit width of the rib without being restricted by the processing limit width of the rib, and the vibrating portion 101 and the fixed portion 10 adjacent in the X-axis direction can be arranged with a gap G1 narrower than the processing limit width of the rib. This allows the eight vibrating portions 101 to be closely spaced within the opening 11 of the fixed portion 10, thereby reducing the width of the optical reflecting element 1 in the X-axis direction.

[0040] Furthermore, in this embodiment, in the second and third outermost vibrating units 101, the distances from the rotation axis R10 to the ribs 122 arranged on the connecting units 112 located at both ends of the vibrating unit 101 are equal. Similarly, in the outermost vibrating unit 101, the distances from the rotation axis R10 to the ribs 122 arranged on the connecting units 112 located at both ends of the vibrating unit 101 and the ribs 121 arranged on the connecting units 111 are equal. In the innermost vibrating unit 101, the distances from the rotation axis R10 to the ribs 122 arranged on the connecting units 112 located at both ends of the vibrating unit 101 and the ribs 123 arranged on the connecting units 113 are equal. This allows the weight balance of the ribs in the vibrating unit 101 to be balanced about the rotation axis R10, thereby allowing the movable unit 40 to rotate in a balanced manner about the rotation axis R10.

[0041] FIG. 5 is a bottom view schematically showing the vicinity of the end portion on the Y-axis positive side of the drive unit 20 on the X-axis negative side.

[0042] As shown in Fig. 5, two connecting portions 112 are adjacent to each other in the X-axis direction near the end of the drive unit 20 on the X-axis negative side and on the Y-axis positive side, and a rib 122 is formed on each connecting portion 112. Here, the connecting portion 112 on the X-axis negative side shown in Fig. 5 is referred to as the "first connecting portion 301," and the connecting portion 112 on the X-axis positive side shown in Fig. 5 is referred to as the "second connecting portion 302." The rib 122 formed on the first connecting portion 301 is referred to as the "first rib 311," and the rib 122 formed on the second connecting portion 302 is referred to as the "second rib 312."

[0043] The entire first rib 311 extends to the end 301a of the first connecting portion 301 on the second connecting portion 302 side. In the region A20 of the second connecting portion 302, which is positioned parallel to the rotation axis R10 with respect to the portion 311a of the first rib 311 that extends to the end 301a, the second rib 312 of the second connecting portion 302 is not arranged at the end A21 on the first connecting portion 301 side. Furthermore, the second rib 312 is arranged in the range of the region A20 other than the end A21.

[0044] <Effects of the embodiment> According to the embodiment, the following effects are achieved.

[0045] 2, each drive unit 20 includes a vibration plate 21 in which the ends of a plurality of vibration units 101 extending in the Y-axis direction (a direction perpendicular to the rotation axis R10) in a plan view are connected in a meandering shape by a plurality of connecting units 112 extending in the X-axis direction (a direction parallel to the rotation axis R10), and ribs 122 arranged on each connecting unit 112. As shown in Fig. 4, gaps G2, G5, and G8 larger than the gap G1 between adjacent vibration units 101 exist on the movable unit 40 side of each rib 121 arranged on each connecting unit 112.

[0046] With this configuration, gaps G2, G5, and G8 larger than gap G1 between adjacent vibrating parts 101 exist on the movable part 40 side of rib 121, so that in the etching process, gap G1 between adjacent vibrating parts 101 can be made smaller than the processing limit width of the rib. Therefore, the size of optical reflecting element 1 in the direction parallel to rotation axis R10 can be reduced.

[0047] As shown in Figure 5, the first rib 311 arranged on the first connecting portion 301 extends to the end 301a on the second connecting portion 302 side, and of the region A20 of the second connecting portion 302 that is positioned parallel to the rotation axis R10 with respect to the portion 311a of the first rib 311 that extends to the end 301a, the second rib 312 on the second connecting portion 302 is not arranged at the end A21 on the first connecting portion 301 side.

[0048] With this configuration, the first rib 311 and the second rib 312 can be arranged on the first connecting portion 301 and the second connecting portion 302, respectively, while making the gap G1 between adjacent first connecting portion 301 and second connecting portion 302 smaller than the processing limit width of the rib.

[0049] As shown in FIG. 5, the second rib 312 is disposed in the area A20 of the second connecting portion 302 except for the end A21.

[0050] According to this configuration, the second ribs 312 can be arranged over a wide range of the second connecting portion 302. This increases the rigidity of the second connecting portion 302, and the resonance frequency of the drive portion 20 can be increased.

[0051] As shown in FIG. 4, the distances from the rotation axis R10 to the ribs 122 arranged on the connecting portions 112 located at both ends of the vibrating portion 101 are equal to each other.

[0052] According to this configuration, the weight balance of the ribs 122 in each vibrating section 101 can be balanced about the rotation axis R10, so that the movable section 40 can be rotated in a well-balanced manner about the rotation axis R10.

[0053] The optical reflecting element 1 includes a fixed portion 10 that supports a pair of drive units 20. As shown in Figure 4, a gap G3 larger than the gap G1 between the connecting portion 112 and the fixed portion 10 exists on the fixed portion 10 side of the rib 122 disposed on the connecting portion 112 adjacent to the fixed portion 10.

[0054] According to this configuration, the gap G3 between the fixed portion 10 and the connecting portion 112 adjacent to the fixed portion 10 can also be reduced, and therefore the size of the optical reflecting element 1 in the direction parallel to the rotation axis R10 can be further reduced.

[0055] 5 , in the above embodiment, the first rib 311 entirely extends to the end 301 a of the first connecting portion 301, and the second rib 312 entirely recedes from the end of the second connecting portion 302 on the first connecting portion 301 side. However, this is not limiting, and the portion extending to the end of the first rib 311 and the portion extending to the end of the second rib 312 may be misaligned in the Y-axis direction.

[0056] FIG. 6 is a bottom view schematically showing the configuration of optical reflecting element 1 according to this modified example, as viewed from the rear surface side (positive direction of the Z axis).

[0057] 2, in the gap between two adjacent ribs 122, the portion where one rib 122 extends to its end and the portion where the other rib 122 extends to its end are offset in the Y-axis direction. In this case, the gap between two adjacent ribs 122 in the X-axis direction is set to be G2 or larger.

[0058] Similarly, in the gap between adjacent ribs 12, 122, the portion where rib 12 extends to the end and the portion where rib 122 extends to the end are misaligned in the Y-axis direction. At this time, the rib 12 formed on the fixed part 10 has a recess 12a where no rib 12 is formed at a position opposite rib 122, and the gap in the X-axis direction between two adjacent ribs 12, 122 is set to be G3 or more.

[0059] In addition, in the gap between adjacent ribs 121, 122, the portion where rib 121 extends to its end and the portion where rib 122 extends to its end are offset in the Y-axis direction. At this time, the gap between adjacent ribs 121, 122 in the X-axis direction is set to be G4 or larger. In addition, in the gap between adjacent ribs 122, 123, the portion where rib 122 extends to its end and the portion where rib 123 extends to its end are offset in the Y-axis direction. At this time, the gap between adjacent ribs 122, 123 in the X-axis direction is set to be G5 or larger.

[0060] FIG. 7 is a bottom view schematically showing the vicinity of the end portion on the Y-axis positive side of the drive unit 20 on the X-axis negative side according to this modified example.

[0061] 5, in this modified example, a portion of the first rib 311 extends to the end 301a. In the region A20 of the second connecting portion 302, which is positioned parallel to the rotation axis R10 with respect to the portion 311a of the first rib 311 that extends to the end 301a, the second rib 312 is not arranged at the end A21 on the first connecting portion 301 side. Furthermore, the second rib 312 is arranged in the range of the region A20 other than the end A21.

[0062] Similarly, a portion of the second rib 312 extends to the end 302a of the second connecting portion 302 on the first connecting portion 301 side. Of the region A10 of the first connecting portion 301 that is positioned parallel to the rotation axis R10 with respect to the portion 312a of the second rib 312 that extends to the end 302a, the first rib 311 is not arranged at the end A11 on the second connecting portion 302 side. Furthermore, the first rib 311 is arranged in the range of the region A10 other than the end A11.

[0063] In other words, only a portion of the first rib 311 extends to the end 301 a on the second connecting portion 302 side, and only a portion of the second rib 312 extends to the end 302 a on the first connecting portion 301 side. The portion 311 a of the first rib 311 extending to the end 301 a and the portion 312 a of the second rib 312 extending to the end 302 a are misaligned in a direction perpendicular to the rotation axis R10 in a plan view.

[0064] In this case, the gap between the first rib 311 and the second rib 312 is G2 at the end on the positive side of the Y axis and the end on the negative side of the Y axis, and the gap near the center position in the Y axis direction is 2×G2−G1.

[0065] <Effects of Modified Example 1> As shown in Figure 7, a portion of the first rib 311 arranged in the first connecting portion 301 extends to the end 301a on the second connecting portion 302 side, and of the region A20 of the second connecting portion 302 that is positioned parallel to the rotation axis R10 with respect to the portion 311a of the first rib 311 that extends to the end 301a, the second rib 312 in the second connecting portion 302 is not arranged at the end A21 on the first connecting portion 301 side.

[0066] With this configuration, the first rib 311 and the second rib 312 can be arranged on the first connecting portion 301 and the second connecting portion 302, respectively, while making the gap G1 between adjacent first connecting portion 301 and second connecting portion 302 smaller than the processing limit width of the rib.

[0067] 7, only a portion of the first rib 311 extends to the end 301a on the second connecting portion 302 side, and only a portion of the second rib 312 extends to the end 302a on the first connecting portion 301 side. The portion 311a of the first rib 311 extending to the end 301a on the second connecting portion 302 side and the portion 312a of the second rib 312 extending to the end 302a on the first connecting portion 301 side are misaligned in the Y-axis direction (the direction perpendicular to the rotation axis R10) in a plan view.

[0068] According to this configuration, the first rib 311 can be disposed up to the end 301 a, while the second rib 312 can be disposed up to the end 302 a. This increases the rigidity of both the first connecting portion 301 and the second connecting portion 302 up to the ends 301 a and 302 a, thereby suppressing unnecessary vibrations in the first connecting portion 301 and the second connecting portion 302 when the movable portion 40 rotates.

[0069] <Modification 2> In modification 1, as shown in FIG. 7 , the portion 311 a of the first rib 311 extending to the end 301 a of the first connecting portion 301 and the portion 312 a of the second rib 312 extending to the end 302 a of the second connecting portion 302 are offset in the Y-axis direction, but the entire first rib 311 and the entire second rib 312 may be offset in the Y-axis direction.

[0070] FIG. 8 is a bottom view schematically showing the configuration of optical reflecting element 1 according to this modified example, as viewed from the rear surface side (positive direction of the Z axis).

[0071] In this modified example, the lengths in the Y-axis direction of the linking portion 112 and the connecting portions 111, 113 are longer than in the first modified example shown in Fig. 6. In the first and second linking portions 112 from the outside, the rib 122 is disposed close to the rotation axis R10, and in the innermost linking portion 112, the rib 122 is disposed far from the rotation axis R10. Furthermore, in the connecting portion 111, the rib 121 is disposed far from the rotation axis R10, and in the connecting portion 113, the rib 123 is disposed far from the rotation axis R10.

[0072] Furthermore, the rib 122 is arranged across both ends of the coupling portion 112 in the X-axis direction and has a rectangular shape in a plan view. The rib 121 is arranged across both ends of the connection portion 111 in the X-axis direction and has a rectangular shape in a plan view. The rib 123 is arranged across both ends of the connection portion 113 in the X-axis direction and has a rectangular shape in a plan view.

[0073] In two adjacent linking portions 112, two ribs 122 are not adjacent to each other in the X-axis direction. In adjacent connecting portions 111 and linking portions 112, the ribs 121 and 122 are not adjacent to each other in the X-axis direction. In adjacent linking portions 112 and linking portions 113, the ribs 122 and 123 are not adjacent to each other in the X-axis direction.

[0074] FIG. 9 is a bottom view schematically showing the vicinity of the end portion on the Y-axis positive side of the drive unit 20 on the X-axis negative side according to this modified example.

[0075] 7, in this modified example, the entire first rib 311 extends to the end 301a. The second rib 312 is not arranged in a region A20 of the second connecting portion 302, which is located parallel to the rotation axis R10 with respect to the portion 311a of the first rib 311 that extends to the end 301a. The second rib 312 is arranged in the range of the second connecting portion 302 other than the region A20.

[0076] Similarly, the entire second rib 312 extends to the end 302a. The first rib 311 is not disposed in an area A10 of the first connecting portion 301, which is parallel to the rotation axis R10 with respect to the portion 312a of the second rib 312 that extends to the end 302a. The first rib 311 is disposed in a range other than the area A10.

[0077] In other words, the first rib 311 extends entirely to the end 301 a on the second connecting portion 302 side, and the second rib 312 extends entirely to the end 302 a on the first connecting portion 301 side. The first rib 311 and the second rib 312 are misaligned in a direction perpendicular to the rotation axis R10 in a plan view.

[0078] In this case as well, the gap between the first rib 311 on the positive side of the X axis and the gap between the second rib 312 on the negative side of the X axis are larger than G2.

[0079] <Effect of Modified Example 2> As shown in Figure 9, the entire first rib 311 arranged on the first connecting portion 301 extends to the end 301a on the second connecting portion 302 side, and the second rib 312 in the second connecting portion 302 is not arranged in the region A20 of the second connecting portion 302 which is positioned parallel to the rotation axis R10 with respect to the portion 311a of the first rib 311 which extends to the end 301a.

[0080] With this configuration, the first rib 311 and the second rib 312 can be arranged on the first connecting portion 301 and the second connecting portion 302, respectively, while making the gap G1 between adjacent first connecting portion 301 and second connecting portion 302 smaller than the processing limit width of the rib.

[0081] <Modification Example 3> In Modification Example 2, as shown in Figure 9, the first connecting portion 301 and the second connecting portion 302 are adjacent to each other in the X-axis direction, but this is not limited to this, and they do not have to be adjacent to each other in the X-axis direction.

[0082] FIG. 10 is a bottom view schematically showing the configuration of optical reflecting element 1 according to this modified example, as viewed from the rear surface side (positive direction of the Z axis).

[0083] In this modification, compared to modification 2 shown in Fig. 8, the size and position of coupling portion 112 and connecting portions 111 and 113 are the same as those of rib 122 and ribs 121 and 123, respectively, in plan view. As a result, outer coupling portion 112 and inner coupling portion 112 are arranged to be offset in the Y-axis direction in plan view. Also, connecting portion 111 and the second outermost coupling portion 112 are arranged to be offset in the Y-axis direction in plan view, and the second outermost coupling portion 112 and connecting portion 113 are arranged to be offset in the Y-axis direction in plan view.

[0084] FIG. 11 is a bottom view schematically showing the vicinity of the end portion on the Y-axis positive side of the drive unit 20 on the X-axis negative side according to this modified example.

[0085] In this modification, compared to the first modification shown in Fig. 9, the first connecting portion 301 and the second connecting portion 302 are arranged side by side, but are not aligned in the X-axis direction. That is, the first connecting portion 301 and the second connecting portion 302 are offset in the Y-axis direction in a plan view. The first rib 311 arranged on the first connecting portion 301 extends to the end 301a on the second connecting portion 302 side, and the second rib 312 arranged on the second connecting portion 302 extends to the end 302a on the first connecting portion 301 side.

[0086] 11 , the first connecting portion 301 (one connecting portion) and the second connecting portion 302 (another connecting portion) beside it are offset in the Y-axis direction (direction perpendicular to the rotation axis R10) in a plan view. The first rib 311 (rib) arranged on the first connecting portion 301 (one connecting portion) extends to the end 301 a on the second connecting portion 302 (another connecting portion) side, and the second rib 312 (rib) arranged on the second connecting portion 302 (another connecting portion) extends to the end 302 a on the first connecting portion 301 (one connecting portion) side.

[0087] According to this configuration, the first rib 311 arranged on the first connecting portion 301 can be arranged to extend to the end 301 a on the second connecting portion 302 side, and the second rib 312 arranged on the second connecting portion 302 can be arranged to extend to the end 302 a on the first connecting portion 301 side. This increases the rigidity of both the first connecting portion 301 and the second connecting portion 302, thereby suppressing unnecessary vibrations from occurring in the first connecting portion 301 and the second connecting portion 302 when the movable portion 40 rotates.

[0088] 5 , in the above embodiment, the second rib 312 is not formed across both ends in the X-axis direction of the second connecting portion 302. However, this is not limiting, and a protrusion may be provided from the end 302 a of the second connecting portion 302 in a direction away from the rotation axis R10, and the second rib 312 may be disposed on this protrusion, so that the second rib 312 is formed across both ends in the X-axis direction of the second connecting portion 302.

[0089] FIG. 12 is a bottom view schematically showing the configuration of optical reflecting element 1 according to this modified example, as viewed from the rear surface side (positive direction of the Z axis).

[0090] 2, in this modified example, a protrusion 112a is formed on the outer end of the connecting portion 112 in a direction away from the rotation axis R10. The protrusion 112a is also made of the active layer 201. In addition, the protrusion 112a has a rib 122 formed across both ends of the protrusion 112a in the X-axis direction. The rib 122 of the protrusion 112a is also made of an intermediate oxide film 202 and a base layer 203.

[0091] Similarly, a protrusion 113a is formed on the outer end of the connecting portion 113 in a direction away from the rotation axis R10. The protrusion 113a is also made of an active layer 201. Furthermore, a rib 123 is formed on the protrusion 113a, extending across both ends of the protrusion 113a in the X-axis direction. The rib 123 of the protrusion 113a is also made of an intermediate oxide film 202 and a base layer 203. The recess 12a of the rib 12 formed on the back surface of the fixed portion 10 is formed in a position facing the outer end of the outermost rib 122 in the X-axis direction.

[0092] FIG. 13 is a bottom view schematically showing the vicinity of the end portion on the Y-axis positive side of the drive unit 20 on the X-axis negative side according to this modified example.

[0093] 5 , in this modified example, the second connecting portion 302 has a protrusion 302b that protrudes from the end 302a on the first connecting portion 301 side in a direction away from the rotation axis R10, and the second rib 312 arranged on the second connecting portion 302 has a portion 312b that extends to the protrusion 302b. Similarly, the first connecting portion 301 has a protrusion 301b that protrudes from the end on the fixed portion 10 side in a direction away from the rotation axis R10, and the first rib 311 arranged on the first connecting portion 301 has a portion 311b that extends to the protrusion 301b.

[0094] <Effects of Modified Example 4> As shown in Figure 13, the second connecting portion 302 has a protrusion 302b that protrudes from the end 302a on the first connecting portion 301 side in a direction away from the rotation axis R10, and the second rib 312 arranged on the second connecting portion 302 has a portion 312b that extends to the protrusion 302b.

[0095] According to this configuration, the second rib 312 can be disposed up to the end 302a of the second connecting portion 302 located on the first connecting portion 301 side, thereby increasing the rigidity of the second connecting portion 302. This makes it possible to suppress unnecessary vibrations from occurring in the first connecting portion 301 and the second connecting portion 302 when the movable portion 40 rotates.

[0096] <Modification 5> In modification 4, as shown in FIG. 13 , in the second connecting portion 302 excluding the protrusion 302 b, the second rib 312 has a rectangular shape in a plan view, but this is not limited thereto, and the width of the second rib 312 in the Y-axis direction may change in stages depending on the position in the X-axis direction.

[0097] FIG. 14 is a bottom view schematically showing the configuration of optical reflecting element 1 according to this modified example, as viewed from the rear surface side (positive direction of the Z axis).

[0098] 12, in this modification, the width of the rib 122 in the Y-axis direction changes stepwise in the connecting portion 112 excluding the protrusion 112a. Similarly, the width of the rib 123 in the Y-axis direction changes stepwise in the connecting portion 113 excluding the protrusion 113a.

[0099] FIG. 15 is a bottom view schematically showing the vicinity of the end portion on the Y-axis positive side of the drive unit 20 on the X-axis negative side according to this modified example.

[0100] 13 , the first rib 311 has a first portion 311c extending parallel to the rotation axis R10 in a region A12 on the rotation axis R10 side of the first connecting portion 301, and a second portion 311d extending from both ends of the first portion 311c in a direction away from the rotation axis R10. Similarly, the second rib 312 has a first portion 312c extending parallel to the rotation axis R10 in a region A22 on the rotation axis R10 side of the second connecting portion 302, and a second portion 312d extending from both ends of the first portion 312c in a direction away from the rotation axis R10.

[0101] <Effects of Modification 5> As shown in FIG. 14, the width of the rib 122 in the Y-axis direction (direction perpendicular to the rotation axis R10) changes in stages.

[0102] This configuration can suppress the weight increase due to the ribs compared to arranging ribs on all of the connecting portions 112, and can effectively reinforce the connecting portions 112. This makes it possible to simultaneously suppress vibrations of the connecting portions 112 and improve the drive characteristics of the drive unit 20.

[0103] The first rib 311 (rib) has a first portion 311c extending parallel to the rotation axis R10 in the region A12 on the rotation axis R10 side of the first connecting portion 301 (connecting portion), and a second portion 311d extending from both ends of the first portion 311c in a direction away from the rotation axis R10.

[0104] According to this configuration, since the first portion 311c is disposed in the region A12 on the rotation axis R10 side of the first connecting portion 301, the first portion 311c can be brought closer to the rotation axis R10, and an increase in the moment of inertia due to an increase in the weight of the second portion 311d can be suppressed, thereby enabling the drive unit 20 to be driven efficiently.

[0105] 14, in Modification 5, the width of ribs 122, 123 in the Y-axis direction changes stepwise, and ribs are provided on protrusions 112a, 113a. However, this is not limiting, and the width of ribs 122, 123 in the Y-axis direction may change stepwise without providing protrusions 112a, 113a.

[0106] FIG. 16 is a bottom view schematically showing the configuration of optical reflecting element 1 according to this modified example, as viewed from the rear surface side (positive direction of the Z axis).

[0107] In this modification, compared to the fourth modification shown in FIG. 14, the protrusions 112a and 113a are omitted, and the ribs disposed on the protrusions 112a and 113a are also omitted.

[0108] In this case, too, gap G1 between two adjacent vibrating parts 101 can be made smaller than the processing limit width of the rib, so the size of optical reflecting element 1 in the direction parallel to rotation axis R10 can be reduced. Furthermore, because the Y-axis direction (width in the direction perpendicular to rotation axis R10) of rib 122 changes in stages, it is possible to suppress vibration of connecting part 112 and improve the drive characteristics of drive part 20 at the same time.

[0109] <Other Modifications> In the above embodiment, of two adjacent ribs 122, only the outer rib 122 may be recessed relative to the gap between the two connecting portions 112, or both ribs 122 may be recessed relative to the gap between the connecting portions 112. Furthermore, of adjacent ribs 121, 122, only the rib 121 may be recessed relative to the gap between the connecting portion 111 and the connecting portion 112, or both ribs 121, 122 may be recessed relative to the gap between the connecting portion 111 and the connecting portion 112. Furthermore, of adjacent ribs 122, 123, only the rib 122 may be recessed relative to the gap between the connecting portion 112 and the connecting portion 113, or both ribs 122, 123 may be recessed relative to the gap between the connecting portion 112 and the connecting portion 113. Furthermore, of adjacent ribs 12 , 122 , only the rib 12 may be recessed relative to the gap between the fixed portion 10 and the connecting portion 112 , or both the ribs 12 , 122 may be recessed relative to the gap between the fixed portion 10 and the connecting portion 112 .

[0110] Similarly, in modified examples 4 to 6, of the two opposing ribs, only the inner rib may be recessed relative to the gap, only the outer rib may be recessed relative to the gap, or both ribs may be recessed relative to the gap.

[0111] In the above embodiment and modified examples 1 to 6, the vibrating unit 101 extends in a direction perpendicular to the rotation axis R10, but this is not a limitation and the vibrating unit 101 may extend in a direction substantially perpendicular to the rotation axis R10. For example, the vibrating unit 101 may extend in a direction slightly tilted from a direction perpendicular to the rotation axis R10. Furthermore, the linking unit 112 and the connecting units 111, 113 extend in a direction parallel to the rotation axis R10, but this is not a limitation and the vibrating unit 101 may extend in a direction substantially parallel to the rotation axis R10. For example, the linking unit 112 and the connecting units 111, 113 may extend in a direction slightly tilted from a direction parallel to the rotation axis R10.

[0112] 5 and 7, in the above embodiment and modified example 1, the second ribs 312 are arranged in the entire region A20 of the second connecting portion 302 except for the end A21 on the first connecting portion 301 side, but this is not limiting, and it is sufficient that the second ribs 312 are not arranged at least on the end A21 of the region A20. For example, the second ribs 312 do not have to be arranged on the end A21 on the first connecting portion 301 side and the end opposite the first connecting portion 301 in the region A20.

[0113] In the above-described modified examples 4 and 5, the protrusions 112a and 113a protrude in a direction perpendicular to the rotation axis R10, but this is not limiting and the protrusions 112a and 113a may extend in a direction away from the rotation axis R10. For example, the protrusions 112a and 113a may extend in a direction slightly inclined with respect to the direction perpendicular to the rotation axis R10.

[0114] In the above-described modified examples 5 and 6, the second portions 311d, 312d (see FIG. 15) extend perpendicular to and away from the rotation axis R10, but the present invention is not limited to this and may extend in any direction away from the rotation axis R10. For example, the second portions 311d, 312d may extend in a direction away from the rotation axis R10 while being slightly tilted in a direction perpendicular to the rotation axis R10.

[0115] In addition, the embodiments of the present invention can be modified in various ways as appropriate within the scope of the technical ideas set forth in the claims.

[0116] (Additional Notes) The above description of the embodiments discloses the following techniques.

[0117] (Technology 1) An optical reflecting element comprising: a movable part provided with a reflective surface; and a pair of drive parts arranged parallel to a rotation axis to sandwich the movable part and rotate the movable part about the rotation axis, wherein each of the drive parts comprises: a vibration plate in which ends of a plurality of vibration parts extending in a direction substantially perpendicular to the rotation axis in a plan view are connected in a meandering shape by a plurality of connecting parts extending in a direction substantially parallel to the rotation axis; and a rib arranged on each of the connecting parts, wherein a gap larger than the gap between adjacent vibration parts exists on the movable part side of each of the ribs.

[0118] According to this technique, since there is a gap on the movable part side of the rib that is larger than the gap between adjacent vibrating parts, the gap between adjacent vibrating parts can be made smaller than the processing limit width of the rib in the etching process, thereby reducing the size of the optical reflecting element in the direction parallel to the rotation axis.

[0119] (Technology 2) An optical reflecting element according to Technology 1, characterized in that: the drive unit has a first connecting unit and a second connecting unit that are adjacent to each other; at least a portion of a first rib arranged on the first connecting unit extends to the end on the second connecting unit side; and the second rib on the second connecting unit is not arranged at least at the end on the first connecting unit side of the region of the second connecting unit that is positioned parallel to the rotation axis relative to the portion of the first rib that extends to the end.

[0120] According to this technique, the first rib and the second rib can be disposed on the first connecting portion and the second connecting portion, respectively, while the gap between the adjacent first connecting portion and the second connecting portion is made smaller than the processing limit width of the rib.

[0121] (Technology 3) The optical reflecting element according to Technology 2, wherein the second rib is disposed in a range other than the end of the region of the second connecting portion.

[0122] This technique allows the second ribs to be disposed over a wide area of ​​the second connecting portion, thereby increasing the rigidity of the second connecting portion and increasing the resonance frequency of the drive portion.

[0123] (Technology 4) An optical reflecting element according to Technology 2 or 3, characterized in that: only a portion of the first rib extends to the end on the second connecting portion side; only a portion of the second rib extends to the end on the first connecting portion side; and the portion of the first rib extending to the end on the second connecting portion side and the portion of the second rib extending to the end on the first connecting portion side are offset in a direction perpendicular to the rotation axis in a planar view.

[0124] According to this technology, the first rib can be disposed up to the end on the second connecting part side, while the second rib can be disposed up to the end on the first connecting part side. This increases the rigidity of both the first connecting part and the second connecting part up to the ends, thereby suppressing unnecessary vibrations in the first connecting part and the second connecting part when the movable part rotates.

[0125] (Technology 5) An optical reflecting element described in any one of technologies 2 to 4, characterized in that the second connecting portion has a protrusion that protrudes from the end on the first connecting portion side in a direction away from the rotation axis, and the second rib arranged on the second connecting portion has a portion that extends to the protrusion.

[0126] This technology allows the second rib to be disposed up to the end of the second connecting part located on the first connecting part side, thereby increasing the rigidity of the second connecting part, thereby suppressing unnecessary vibrations in the first connecting part and the second connecting part when the movable part rotates.

[0127] (Technology 6) An optical reflecting element described in Technology 1, characterized in that one of the connecting portions and another connecting portion next to it are offset in a direction perpendicular to the rotation axis in a planar view, the rib arranged on the one connecting portion extends to the end on the other connecting portion side, and the rib arranged on the other connecting portion extends to the end on the one connecting portion side.

[0128] According to this technology, the rib arranged on one connecting part can be arranged to extend to the end on the other connecting part side, and the rib arranged on the other connecting part can be arranged to extend to the end on the one connecting part side. This increases the rigidity of both the one connecting part and the other connecting part, thereby suppressing unnecessary vibrations in the one connecting part and the other connecting part when the movable part rotates.

[0129] (Technology 7) The optical reflecting element according to any one of Technologies 1 to 6, wherein the width of the rib in the direction perpendicular to the rotation axis changes stepwise.

[0130] This technology can suppress the weight increase caused by ribs compared to placing ribs on all of the connecting parts, and can effectively reinforce the connecting parts, thereby achieving both vibration suppression at the connecting parts and improved drive characteristics of the drive unit.

[0131] (Technology 8) In the optical reflecting element described in Technology 7, the rib has a first portion extending parallel to the pivot axis in the region on the pivot axis side of the connecting portion, and a second portion extending from both ends of the first portion in a direction away from the pivot axis.

[0132] According to this technology, since the first portion is disposed in the region on the pivot axis side of the connecting portion, the first portion can be brought closer to the pivot axis, and an increase in the moment of inertia due to an increase in the weight of the second portion can be suppressed, thereby enabling the drive unit to be driven efficiently.

[0133] (Technology 9) An optical reflecting element according to any one of technologies 1 to 8, characterized in that the distances from the rotation axis to the ribs arranged on the connecting portions at both ends of the vibration portion are equal to each other.

[0134] This technique allows the weight balance of the ribs in each vibrating section to be balanced about the rotation axis, thereby allowing the movable section to rotate in a well-balanced manner about the rotation axis.

[0135] (Technology 10) An optical reflecting element described in any one of technologies 1 to 9, characterized in that it comprises a fixed portion that supports the pair of driving portions, and on the fixed portion side of the rib arranged on the connecting portion adjacent to the fixed portion, there is a gap that is larger than the gap between the connecting portion and the fixed portion.

[0136] According to this technique, the gap between the fixed portion and the connecting portion adjacent to the fixed portion can also be reduced, and therefore the size of the optical reflecting element in the direction parallel to the rotation axis can be further reduced.

[0137] REFERENCE SIGNS LIST 1 Optical reflecting element 10 Fixed portion 20 Drive portion 21 Vibration plate 40 Movable portion 40a Reflecting surface 101 Vibration portion 112 Connecting portion (first connecting portion, second connecting portion) 112a Projection 122 Rib (first rib, second rib) 301 First connecting portion (connecting portion) 301a End 301b Projection 302 Second connecting portion (connecting portion) 302a End 302b Projection 311 First rib (rib) 311a, 311b Part 311c First portion 311d Second portion 312 Second rib (rib) 312a, 312b Part 312c First portion 312d Second portion A10, A20 Area A11, A21 End A12, A22 Area G2 clearance G3 clearance G2, G5, G8 clearance R10 rotation axis

Claims

1. An optical reflecting element comprising: a movable part provided with a reflective surface; and a pair of drive parts arranged parallel to a rotation axis to sandwich the movable part and rotate the movable part about the rotation axis, wherein each of the drive parts comprises: a diaphragm in which ends of a number of vibration parts extending in a direction substantially perpendicular to the rotation axis in a planar view are connected in a meandering shape by a number of connecting parts extending in a direction substantially parallel to the rotation axis; and a rib arranged on each of the connecting parts, wherein a gap exists on the movable part side of each of the ribs that is larger than the gap between adjacent vibration parts.

2. An optical reflecting element as described in claim 1, characterized in that the driving section has a first connecting section and a second connecting section which are adjacent to each other, a first rib arranged on the first connecting section extends at least partially to the end on the second connecting section side, and in the region of the second connecting section which is positioned parallel to the rotation axis relative to the portion of the first rib which extends to the end, at least the end on the first connecting section side is not provided with a second rib on the second connecting section.

3. An optical reflecting element as described in claim 2, characterized in that the second rib is arranged in an area other than the end of the region of the second connecting portion.

4. An optical reflecting element as described in claim 2, characterized in that: only a portion of the first rib extends to the end on the second connecting part side; only a portion of the second rib extends to the end on the first connecting part side; and the portion of the first rib extending to the end on the second connecting part side and the portion of the second rib extending to the end on the first connecting part side are offset in a direction perpendicular to the rotation axis in a planar view.

5. An optical reflecting element as described in claim 2, characterized in that the second connecting portion has a protrusion that protrudes from the end on the first connecting portion side in a direction away from the rotation axis, and the second rib arranged on the second connecting portion has a portion extending to the protrusion.

6. An optical reflecting element as described in claim 1, characterized in that one of the connecting parts and another connecting part beside it are offset in a direction perpendicular to the rotation axis in a planar view, the rib arranged on the one connecting part extends to the end on the other connecting part side, and the rib arranged on the other connecting part extends to the end on the one connecting part side.

7. An optical reflecting element as claimed in claim 1, characterized in that the width of said rib in the direction perpendicular to said rotation axis changes stepwise.

8. An optical reflecting element as described in claim 7, characterized in that the rib has a first portion extending parallel to the pivot axis in the region on the pivot axis side of the connecting portion, and a second portion extending from both ends of the first portion in a direction away from the pivot axis.

9. An optical reflecting element as claimed in claim 1, characterized in that the distances from the rotation axis to the ribs arranged on the connecting parts at both ends of the vibration part are equal to each other.

10. An optical reflecting element as claimed in any one of claims 1 to 9, comprising a fixed portion supporting the pair of driving portions, and wherein a gap exists on the fixed portion side of the rib arranged on the connecting portion adjacent to the fixed portion, the gap being larger than the gap between the connecting portion and the fixed portion.

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