light polarizer

Abstract

The present invention provides an optical deflector with a simple configuration that prevents damage to the drive unit when an impact is applied to the optical deflector, while also enabling smooth operation of the drive unit. [Solution] The optical deflector 2 comprises a driving element 1 and a support substrate 40 that supports the driving element 1. The driving element 1 comprises a movable part 10 provided with a reflective surface 11, a fixed part 30 installed on the support substrate 40, and a driving unit 20 installed between the movable part 10 and the fixed part 30 that rotates the movable part 10 about a pivot axis R10. The driving unit 20 comprises a plurality of vibrating parts 21 and a plurality of connecting parts 23a, 23b, 23c that connect the plurality of vibrating parts 21 in a meander manner and each have ribs that protrude downward to the height of the lower surface of the fixed part 30. The support substrate 40 has a receiving part 42 for receiving the lower surface of the rib of the connecting part 23a, and the movable part 10 is rotated by driving the plurality of vibrating parts 21 to bend only upward.

Description

Technical Field

[0001] The present invention relates to an optical deflector including a movable part having a reflecting surface.

Background Art

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

[0003] The following Patent Document 1 describes this type of optical deflector. This optical deflector includes an actuator part in which a plurality of cantilever piezoelectric actuators are connected in a meander shape. A stopper that faces the base end part of the actuator part connected to the fixed part with a predetermined gap and a stopper that faces the connection part of the first and second cantilever piezoelectric actuators in order from the base end part with a predetermined gap are disposed. Each gap is adjusted to a size that does not limit the normal operation of the cantilever piezoelectric actuator and can prevent damage to the part of the actuator part facing each stopper when an impact is applied in the vertical direction.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the optical deflector of Patent Document 1 above, it is necessary to accurately process the stopper while considering both the normal operation of the cantilever piezoelectric actuator and prevention of damage due to impact.

[0006] In view of these problems, the present invention aims to provide an optical deflector with a simple configuration that prevents damage to the drive unit when an impact is applied to the optical deflector, and that allows the drive unit to be driven smoothly. [Means for solving the problem]

[0007] The main aspect of the present invention relates to an optical deflector. The optical deflector according to this aspect comprises a driving element and a support substrate that supports the driving element. The driving element comprises a movable part provided with a reflective surface, a fixed part installed on the support substrate, and a drive unit installed between the movable part and the fixed part that rotates the movable part about a pivot axis. The drive unit comprises a plurality of vibrating parts, a plurality of connecting parts that connect the plurality of vibrating parts in a meander manner and each having a rib that protrudes downward to the height of the lower surface of the fixed part, and a piezoelectric body provided on the upper side of the plurality of vibrating parts. The support substrate has a receiving part formed thereon for receiving the lower surface of the rib of the outermost connecting part of the plurality of connecting parts that is furthest from the movable part, and the movable part is rotated by driving the plurality of vibrating parts to bend upward only.

[0008] In a configuration without a support section, if the optical deflector is subjected to an impact and the drive section is displaced excessively downward, the greatest stress is generated at the connection section connecting the drive section and the fixed section, followed by the outermost connection section, which is furthest from the movable section among the multiple connection sections. In contrast, with the optical deflector according to this embodiment, when the optical deflector is subjected to an impact, the outer connection section is supported by the support section and does not displace substantially downward. Therefore, no great stress is generated at the outer connection section, nor at the connection section on the fixed section side relative to the outer connection section. This prevents damage to the drive section due to excessive downward displacement when the optical deflector is subjected to an impact.

[0009] Furthermore, when the movable part is driven, the multiple vibrating parts are driven to bend only upward, so the outer connecting part does not displace substantially downward (towards the receiving part). Therefore, even if the lower surface of the outer connecting part is supported by the receiving part, the receiving part does not obstruct the driving of the drive part when the movable part is driven. Consequently, even if a receiving part is provided, the drive part can be driven smoothly.

[0010] Furthermore, since the outer connecting portion does not substantially move downward when the movable part is driven, the receiving portion may be in contact with or close to the lower surface of the outer connecting portion, and it is not necessary to provide a gap of a specified size between the outer connecting portion and the receiving portion to allow the drive portion to move. As a result, the receiving portion can be simply constructed as a stopper to support the lower surface of the outer connecting portion.

[0011] Therefore, according to the optical deflector of this embodiment, with a simple configuration, damage to the drive unit when an impact is applied to the optical deflector can be prevented, and the drive unit can be driven smoothly. [Effects of the Invention]

[0012] As described above, the present invention provides an optical deflector with a simple configuration that prevents damage to the drive unit when an impact is applied to the optical deflector, and also enables smooth operation of the drive unit.

[0013] The effects and significance of the present invention will become even clearer from the description of the embodiments shown below. However, the embodiments shown below are merely examples of how to implement the present invention, and the present invention is not limited in any way to those described in the embodiments below. [Brief explanation of the drawing]

[0014] [Figure 1] Figure 1 is a schematic top view showing the configuration of a drive element according to an embodiment. [Figure 2] Figure 2 is a schematic bottom view showing the configuration of the drive element according to the embodiment. [Figure 3]FIG. 3 is a top view showing the configuration of a support substrate that supports a drive element from the lower surface side according to an embodiment. [Figure 4] FIG. 4 is a top view showing the configuration of an optical deflector according to an embodiment. [Figure 5] FIG. 5 is a diagram schematically showing an end face when the optical deflector is cut in a plane parallel to the X-Z plane passing through the rotation axis according to an embodiment. [Figure 6] FIG. 6 is a diagram schematically showing an end face when the optical deflector is cut in a plane parallel to the Y-Z plane at the positions C1-C2 in FIG. 4 according to an embodiment. [Figure 7] FIG. 7 is a diagram schematically showing the configuration of an optical deflection device according to an embodiment. [Figure 8] FIGS. 8(a) and (b) are diagrams showing the first drive voltage applied to the first group of piezoelectric bodies and the second drive voltage applied to the second group of piezoelectric bodies according to an embodiment, respectively. [Figure 9] FIGS. 9(a) and (b) are diagrams schematically showing the first drive state and the second drive state according to an embodiment, respectively. [Figure 10] FIGS. 10(a) and (b) are diagrams showing the simulation results of stress distributions according to a comparative example and an embodiment, respectively. [Figure 11] FIGS. 11(a) and (b) are top views showing the configuration of a support substrate according to Modification 1. [Figure 12] FIGS. 12(a) and (b) are top views showing the configuration of a support substrate according to Modification 1. [Figure 13] FIGS. 13(a) and (b) are top views showing the configuration of a support substrate according to Modification 2. [Figure 14] FIGS. 14(a) and (b) are top views showing the configuration of a support substrate according to Modification 2. [Figure 15] FIGS. 15(a) and (b) are top views showing the configuration of a support substrate according to Modification 2. [Figure 16] FIGS. 16(a) and (b) are top views showing the configuration of a support substrate according to Modification 3.

Mode for Carrying Out the Invention

[0015] In the following embodiments, there are described a drive element 1 that scans a beam incident on a reflecting surface by rotation of the reflecting surface, an optical deflector 2 including the drive element 1, and an optical deflection device 3 that mounts the optical deflector 2 and displays a predetermined image by scanning of the beam. However, the device on which the optical deflector 2 is mounted is not limited to the optical deflection device 3. For example, the optical deflector 2 may be mounted on an object detection device that detects the presence or absence of an object and the distance to the object in the projection direction of the beam.

[0016] Hereinafter, embodiments of the present invention will be described with reference to the drawings. For convenience, X, Y, and Z axes orthogonal to each other are added to each drawing. The positive direction of the Z axis is the vertically upward direction and is the thickness direction (height direction) of the drive element 1 and the optical deflector 2. The X axis is parallel to the rotation axis R10 of the drive element 1 and the optical deflector 2.

[0017] FIG. 1 is a top view schematically showing the configuration of the drive element 1.

[0018] The drive element 1 includes a movable part 10, a pair of drive parts 20, and a fixed part 30. The drive element 1 has a point-symmetric shape about the center C10 in plan view.

[0019] The movable part 10 is circular in plan view. A reflecting surface 11 is formed on the upper surface (the surface on the positive Z-axis side) of the movable part 10. The reflecting surface 11 may be formed by mirror-finishing the upper surface of the movable part 10, or may be formed by forming a reflecting film on the upper surface of the movable part 10. The movable part 10 rotates about the rotation axis R10 by driving of the pair of drive parts 20.

[0020] The pair of drive parts 20 are arranged on the negative X-axis side and the positive X-axis side of the movable part 10, and support the movable part 10 from the negative X-axis side and the positive X-axis side. Each drive part 20 has a meander shape that snakes in the Y-axis direction in plan view. The drive parts 20 on the negative X-axis side and the positive X-axis side are configured to be point-symmetric about the center C10 in plan view.

[0021] One drive unit 20 comprises, in plan view, four vibrating parts 21, a connecting part 22, connecting parts 23a, 23b, 23c, a connecting part 24, and four piezoelectric elements 25.

[0022] The four vibrating parts 21 have a rectangular shape with their longest side parallel to the Y-axis in a plan view, and are arranged side by side with gaps in the X-axis direction. The connecting part 22 connects the fixed part 30 to the Y-axis end of the vibrating part 21 furthest from the movable part 10. The connecting parts 23a, 23b, and 23c connect the four vibrating parts 21 in a meander manner. That is, the connecting parts 23a, 23b, and 23c each connect the Y-axis ends of two adjacent vibrating parts 21 in the X-axis direction. The connecting parts 23a, 23b, and 23c have a rectangular shape with their longest side parallel to the X-axis. The connecting part 24 connects the Y-axis end of the vibrating part 21 closest to the movable part 10 to the movable part 10.

[0023] The piezoelectric element 25 has a rectangular shape in plan view, with its longer side parallel to the Y-axis direction. In one drive unit 20, four piezoelectric elements 25 are each installed above (on the positive Z-axis side of) four vibrating units 21. As will be described later with reference to Figure 5, each piezoelectric element 25 has a configuration in which a piezoelectric layer 112 is sandwiched between a lower electrode layer 111 and an upper electrode layer 113. Each piezoelectric element 25 is connected by a wiring section to an electrode pad provided on the upper surface of the fixed unit 30.

[0024] A first drive voltage with the same phase is applied to a first group, which includes the 1st and 3rd piezoelectric elements 25 from the negative X-axis side of the drive unit 20 on the negative X-axis side, and the 2nd and 4th piezoelectric elements 25 from the positive X-axis side of the drive unit 20 on the positive X-axis side. A second drive voltage with the same phase is applied to a second group, which includes the 2nd and 4th piezoelectric elements 25 from the negative X-axis side of the drive unit 20 on the negative X-axis side, and the 1st and 3rd piezoelectric elements 25 from the positive X-axis side of the drive unit 20 on the positive X-axis side. In Figure 1, for convenience, the piezoelectric elements 25 in the first group are marked with the same diagonal lines, and the piezoelectric elements 25 in the second group are marked with the same diagonal lines.

[0025] The fixed portion 30 comprises a rectangular frame portion 31 in plan view. The frame portion 31 has an opening 31a formed in the center in plan view, which penetrates the frame portion 31 in the vertical direction (Z-axis direction). Connection portions 22 of the drive unit 20 are connected to the negative X-axis end and the positive X-axis end of the opening 31a, respectively. In other words, the fixed portion 30 supports the movable portion 10 via a pair of drive units 20.

[0026] Figure 2 is a schematic bottom view showing the configuration of the drive element 1.

[0027] In Figure 2, for convenience, the active layer 101 and the base layer 103, which will be described later in Figure 5, are shown with different shaded lines. The active layer 101 and the base layer 103 are open on the lower side (negative Z-axis side) in the shaded region. Each part of the drive element 1 includes the integrally formed active layer 101. The connection part 22, connecting parts 23a, 23b, 23c, connection part 24, and fixed part 30 include the base layer 103 formed on the lower side of the active layer 101. The movable part 10 includes a ring-shaped base layer 103 formed around its lower surface. In the connection part 22, connecting parts 23a, 23b, 23c, connection part 24, fixed part 30, and movable part 10, the strength of these parts is increased by forming the base layer 103 on the lower side of the active layer 101.

[0028] Figure 3 is a top view showing the configuration of the support substrate 40 that supports the drive element 1 from the bottom side.

[0029] The support substrate 40 has an outer contour that is slightly larger than the outer contour of the drive element 1 in a plan view. The support substrate 40 has a rectangular frame portion 41 in a plan view. In a plan view, the frame portion 41 has a rectangular opening 41a formed in the center that penetrates the frame portion 41 in the vertical direction (Z-axis direction). In a plan view, the opening 41a has the same shape as the opening 31a of the fixing portion 30 of the drive element 1. Receiving portions 42 are formed at the corners of the opening 41a on the negative X-axis and negative Y-axis sides, and at the corners of the opening 41a on the positive X-axis and positive Y-axis sides. The frame portion 41 and the receiving portion 42 are integrally formed, but for convenience, the boundary between the frame portion 41 and the receiving portion 42 is shown by a dashed line in Figure 3.

[0030] Adhesive 50 (see Figures 5 and 6) is applied to the entire lower surface of the fixing portion 30 of the drive element 1, and the lower surface of the fixing portion 30 and the upper surface of the frame portion 41 are bonded together via the adhesive 50. In Figure 3, for convenience, the outer contour of the drive element 1, which is installed on top of the support substrate 40, is shown by a dashed line, and the area where the adhesive 50 is applied is shown by a diagonal line.

[0031] Figure 4 is a top view showing the configuration of the optical deflector 2.

[0032] The optical deflector 2 is completed when the lower surface of the fixing part 30 shown in Figure 1 is bonded to the upper surface of the support substrate 40 shown in Figure 3. The receiving part 42 of the support substrate 40 is positioned on the lower side of the connecting part 23a so as to include the entire area of ​​the connecting part 23a in a plan view.

[0033] Figure 5 schematically shows the end face when the optical deflector 2 is cut by a plane passing through the rotation axis R10 and parallel to the XZ plane in Figure 4. For convenience, only a portion of the drive unit 20 is shown in Figure 5.

[0034] The movable part 10, the pair of drive parts 20, and the fixed part 30 are connected by a common active layer 101. The outline of the drive element 1 in plan view is formed by etching an SOI wafer in which an active layer 101 made of silicon (Si), an intermediate oxide film 102 made of silicon dioxide (SiO2), and a base layer 103 made of silicon (Si) are stacked in that order from top to bottom.

[0035] Furthermore, the base layer 103 and the intermediate oxide film 102 are removed from the SOI wafer by etching. At this time, the base layer 103 and the intermediate oxide film 102 remain on the fixed portion 30, ensuring its thickness. The base layer 103 and the intermediate oxide film 102 also remain on the connection portion 22, connecting portions 23a, 23b, 23c, and connection portion 24 of the drive portion 20, ensuring its thickness. The base layer 103 and the intermediate oxide film 102 also remain on the outer circumference of the movable portion 10, ensuring its thickness. The base layer 103 and the intermediate oxide film 102 remaining on the connection portion 22, connecting portions 23a, 23b, 23c, connection portion 24, and the outer circumference of the movable portion 10 form ribs that protrude in the Z-axis direction relative to the active layer 101. These ribs protrude in the negative Z-axis direction (downward) to the height of the lower surface of the fixed portion 30.

[0036] The piezoelectric element 25 is formed on the vibrating section 21, which consists of the active layer 101. The piezoelectric element 25 has a laminated structure in which a lower electrode layer 111, a piezoelectric layer 112, and an upper electrode layer 113 are stacked in that order from bottom to top. The lower electrode layer 111 is made of, for example, platinum (Pt). The piezoelectric layer 112 is made of, for example, PZT (lead zirconate titanate: Pb(Zr,Ti)O3). The upper electrode layer 113 is made of, for example, gold (Au). However, the materials constituting the lower electrode layer 111, the piezoelectric layer 112, and the upper electrode layer 113 are not limited to these.

[0037] The support substrate 40 is fixed to the lower surface of the fixing portion 30 (the negative Z-axis side of the base layer 103) by adhesive 50. The support substrate 40 is made of a material such as a glass epoxy substrate, a paper phenolic substrate, a ceramic substrate, or a glass substrate. Both the lower surface of the fixing portion 30 and the upper surface of the support substrate 40 are planes parallel to the XY plane.

[0038] Figure 6 schematically shows the end face when the optical deflector 2 is cut by a plane parallel to the YZ plane at the position C1-C2 in Figure 4.

[0039] Connecting portions 23a and 23b are provided at the negative and positive Y-axis ends of the vibrating portion 21 at positions C1-C2, respectively. Ribs made of an intermediate oxide film 102 and a base layer 103 are formed on the lower surface of the connecting portion 23a. A receiving portion 42 is positioned below the connecting portion 23a. The receiving portion 42 extends from the inner side of the frame portion 41 of the support substrate 40, that is, from the positive Y-axis side of the frame portion 41 located on the negative Y-axis side in Figure 6, down to below the connecting portion 23a.

[0040] The lower surface of the connecting portion 23a, the lower surface of the fixing portion 30, and the upper surface of the support substrate 40 are all parallel to the XY plane. The lower surface of the connecting portion 23a and the lower surface of the fixing portion 30 are positioned substantially at the same location in the Z-axis direction, and the upper surface of the receiving portion 42 and the upper surface of the frame portion 41 are positioned substantially at the same location in the Z-axis direction. No other material, such as adhesive 50, is interposed between the connecting portion 23a and the receiving portion 42.

[0041] When the drive element 1 is not driven (neutral state), the receiving portion 42 only needs to substantially support the lower surface of the connecting portion 23a. That is, in the neutral state, the lower surface of the connecting portion 23a may rest on the receiving portion 42 and the lower surface of the connecting portion 23a may be in contact with the upper surface of the receiving portion 42, or the receiving portion 42 may be slightly separated from the lower surface of the connecting portion 23a.

[0042] Figure 7 is a schematic diagram showing the configuration of the optical deflection device 3.

[0043] The optical deflection device 3 comprises an optical deflector 2 and a control circuit 300. The optical deflection device 3 is, for example, a device that displays a predetermined image by scanning a beam.

[0044] The support substrate 40 of the optical deflector 2 includes a plurality of wires 210 and a connector 220. The wires 210 and connector 220 are installed on the upper surface (the positive Z-axis side) of the support substrate 40. The wires 210 electrically connect the drive element 1 and the connector 220. Electrode pads connected to eight piezoelectric elements 25 are installed on the upper surface of the fixed portion 30 of the drive element 1, and the plurality of wires 210 are electrically connected to the electrode pads of the drive element 1.

[0045] The control circuit 300 comprises a control unit 301 and a voltage application unit 302. The voltage application unit 302 is electrically connected to the connector 220. The control unit 301 controls the voltage application unit 302 to apply a first drive voltage and a second drive voltage to the first group of piezoelectric elements 25 and the second group of piezoelectric elements 25 shown in Figure 1, respectively.

[0046] Figures 8(a) and 8(b) show the first drive voltage applied to the first group of piezoelectric elements 25 and the second drive voltage applied to the second group of piezoelectric elements 25, respectively.

[0047] In the first and second drive voltages, the state in which voltage V is applied and the state in which no voltage is applied are repeated with equal periods T. The phases of the first and second drive voltages are shifted by half a period T / 2, so when voltage V is applied in the first drive voltage, no voltage is applied in the second drive voltage, and when no voltage is applied in the first drive voltage, voltage V is applied in the second drive voltage.

[0048] The piezoelectric element 25 is configured to deform due to the inverse piezoelectric effect when a voltage V is applied, causing the upper side of the piezoelectric element 25 to contract. When the upper side of the piezoelectric element 25 contracts, the vibrating section 21 on which the piezoelectric element 25 is installed bends upward. As a result, the movable section 10 rotates about the pivot axis R10 (see Figure 1), light incident on the movable section 10 is reflected by the reflective surface 11 of the movable section 10, and the reflected light is scanned in the scanning area.

[0049] Figures 9(a) and 9(b) schematically show the first drive state and the second drive state, respectively.

[0050] Hereinafter, the vibration section 21 furthest from the movable section 10 in the drive unit 20 will be referred to as the "first vibration section," and the vibration section 21 adjacent to the first vibration section will be referred to as the "second vibration section." Figures 9(a) and (b) show the first and second vibration sections of the drive unit 20 on the negative X-axis side. Also, for convenience, in Figures 9(a) and (b), the first vibration section, the connecting section 22 and the linking section 23a located on the positive and negative Y-axis sides of the first vibration section, and the piezoelectric element 25 installed on the first vibration section are shown by solid lines, while the second vibration section, the linking section 23b located on the positive Y-axis side of the second vibration section, and the piezoelectric element 25 installed on the second vibration section are shown by dashed lines.

[0051] When a voltage V is applied to the piezoelectric element 25 of the first vibrating part, as shown in Figure 9(a), the piezoelectric element 25 of the first vibrating part deforms due to the inverse piezoelectric effect, causing the first vibrating part to bend upward. At this time, the position of the connection part 22 on the positive Y-axis side of the first vibrating part does not change because it is directly connected to the fixed part 30. On the other hand, the connecting part 23a on the negative Y-axis side of the first vibrating part moves upward (away from the receiving part 42) in accordance with the deformation of the first vibrating part. Also, when a voltage V is applied to the piezoelectric element 25 of the first vibrating part, no voltage is applied to the piezoelectric element 25 of the second vibrating part. Therefore, the second vibrating part does not deform, and the connecting part 23b on the positive Y-axis side of the second vibrating part moves downward from the position of the connecting part 23b when the driving element 1 is not driven (neutral state).

[0052] When no voltage is applied to the piezoelectric element 25 of the first vibrating section, as shown in Figure 9(b), the piezoelectric element 25 of the first vibrating section is not deformed, and the lower surface of the connecting portion 23a on the negative Y-axis side of the first vibrating section is positioned substantially at the same location as the upper surface of the receiving portion 42 in the vertical direction. Also, when no voltage is applied to the piezoelectric element 25 of the first vibrating section, a voltage V is applied to the piezoelectric element 25 of the second vibrating section. As a result, the piezoelectric element 25 of the second vibrating section deforms due to the inverse piezoelectric effect, and the second vibrating section bends upward. At this time, the connecting portion 23b on the positive Y-axis side of the second vibrating section moves upward from the position of the connecting portion 23b in the neutral state.

[0053] When voltage is applied to the piezoelectric elements 25 of the first and second groups as shown in Figures 8(a) and (b), the first driving state in Figure 9(a) and the second driving state in Figure 9(b) are repeatedly alternated. At this time, the connecting portion 23a does not substantially move below the upper surface of the receiving portion 42. As a result, the pair of driving units 20 are driven without being obstructed by the receiving portion 42.

[0054] Incidentally, if an optical deflector equipped with a meander-shaped drive unit is subjected to impact, such as by dropping, damage to the drive unit may occur. For example, in the comparative example optical deflector 2 in which the receiving portion 42 is not formed, if an impact is applied, the movable portion 10 and the pair of drive units 20 will be greatly displaced in the Z-axis direction, and the pair of drive units 20 may be damaged. In contrast, in the optical deflector 2 of the embodiment, if an impact is applied, since the receiving portion 42 is positioned below the connecting portion 23a of the drive unit 20, the connecting portion 23a is supported by the receiving portion 42, and the maximum stress generated in the pair of drive units 20 is suppressed compared to the comparative example. As a result, in the embodiment, damage to the drive unit 20 can be suppressed compared to the comparative example.

[0055] Referring to Figures 10(a) and (b), the inventors' simulations of the stress distribution that occurs when an impact is applied in the comparative example and embodiment will be explained.

[0056] Figures 10(a) and 10(b) show the simulation results of the stress distribution for the comparative example and the embodiment, respectively.

[0057] In the comparative example configuration, the movable part 10 and a pair of drive units 20 of the drive element 1 were set up. In the embodiment configuration, the movable part 10 of the drive element 1, the pair of drive units 20, and a receiving part 42 were set up, and a gap of 1 μm was provided between the lower surface of the connecting part 23a and the upper surface of the receiving part 42 when the drive element 1 was not driven (neutral state). In both the comparative example and the embodiment configuration, the outside of the pair of connecting parts 22 was connected to the fixed end. A predetermined impact was then applied to the configurations of the comparative example and the embodiment to move the movable part 10 and the pair of drive units 20 in the negative Z-axis direction, and the stress generated in the movable part 10 and the pair of drive units 20 at this time was obtained by simulation. In Figures 10(a) and (b), the color simulation results are shown in grayscale for convenience.

[0058] Note that in Figure 10(b), for convenience, the receiving portion 42 is shown to be long in the direction toward the movable portion 10 and overlapping the connecting portion 23c; however, in the simulation settings, the receiving portion 42 is positioned only below the connecting portion 23a.

[0059] In the comparative example, as shown in Figure 10(a), the greatest stress occurred at the connection portion 22, followed by the connecting portion 23a, indicated by the dashed line. On the other hand, in the embodiment, as shown in Figure 10(b), the connecting portion 23a is supported by the receiving portion 42 and does not displace substantially, so no great stress occurs at the connecting portion 23a, nor at the connection portion 22. In the embodiment, the greatest stress occurred at the connecting portion 23b, indicated by the dashed line. Comparing the maximum stress that occurred at the connecting portion 23a in the comparative example with the maximum stress that occurred at the connecting portion 23b in the embodiment, the maximum stress in the embodiment was 14.9% lower than the maximum stress in the comparative example.

[0060] Furthermore, although the stress generated in the connecting portion 23b in the embodiment was greater than the stress generated in the connecting portion 23b in the comparative example, as described above, the stress generated in the connecting portion 23b in the embodiment was not as great as the stress generated in the connecting portion 23a in the comparative example.

[0061] From the above, in this embodiment, by simply providing a receiving portion 42 to the connecting portion 23a, damage to both the connecting portion 23a and the connecting portion 22 can be suppressed simultaneously. Furthermore, the stress on the other connecting portions 23b and 23c is also less likely to become excessively large due to their mass and distance from the movable portion 10. Therefore, by simply providing a receiving portion 42 to the connecting portion 23a, damage to the entire drive unit 20 can be prevented when an impact is applied.

[0062] <Effects of the Embodiment> According to the embodiment, the following effects are achieved.

[0063] As shown in Figure 4, the optical deflector 2 comprises a driving element 1 and a support substrate 40 that supports the driving element 1. The driving element 1 comprises a movable part 10 on which a reflective surface 11 is provided, a fixed part 30 installed on the support substrate 40, and a driving unit 20 installed between the movable part 10 and the fixed part 30 that rotates the movable part 10 about a pivot axis R10. The driving unit 20 comprises a plurality of vibrating parts 21, a plurality of connecting parts 23a, 23b, 23c that connect the plurality of vibrating parts 21 in a meander manner and each having ribs that protrude downward to the height of the lower surface of the fixed part 30, and a piezoelectric body 25 provided on the upper side of the plurality of vibrating parts 21. The support substrate 40 has a receiving portion 42 formed therein to receive the lower surface of the rib of the connecting portion 23a (outer connecting portion) that is furthest from the movable portion 10 among the multiple connecting portions 23a, 23b, and 23c, and the movable portion 10 is rotated by driving the multiple vibrating portions 21 to bend upward only.

[0064] As shown in the simulation results of the comparative example in Figure 10(a), in a configuration where the receiving portion 42 is not formed, if the optical deflector is subjected to an impact and the drive unit 20 is displaced excessively downward, the greatest stress is generated in the connecting portion 22 that connects the drive unit 20 and the fixed portion 30, followed by a large stress in the connecting portion 23a, which is the furthest from the movable portion 10 among the multiple connecting portions 23a, 23b, and 23c. In contrast, with the above configuration, as shown in the simulation results of the embodiment in Figure 10(b), when the optical deflector 2 is subjected to an impact, the connecting portion 23a is supported by the receiving portion 42 and does not displace substantially downward. Therefore, no large stress is generated in the connecting portion 23a, and no large stress is generated in the connecting portion 22. This prevents damage to the drive unit 20 due to excessive downward displacement when the optical deflector 2 is subjected to an impact.

[0065] Furthermore, when the movable part 10 is driven, the multiple vibrating parts 21 are driven to bend only upward, so the connecting part 23a does not displace substantially downward (towards the receiving part 42). Therefore, even if the lower surface of the connecting part 23a is supported by the receiving part 42, the receiving part 42 does not obstruct the driving of the drive unit 20 when the movable part 10 is driven. Thus, even if the receiving part 42 is provided, the drive unit 20 can be driven smoothly.

[0066] Furthermore, since the connecting portion 23a does not substantially move downward when the movable portion 10 is driven, the receiving portion 42 may be in contact with or close to the lower surface of the connecting portion 23a, and it is not necessary to provide a gap of a specified size between the connecting portion 23a and the receiving portion 42 to allow the drive portion 20 to be driven. As a result, the receiving portion 42 can be simply configured as a stopper to receive the lower surface of the connecting portion 23a.

[0067] Therefore, with the above configuration, damage to the drive unit 20 when an impact is applied to the optical deflector 2 can be prevented with a simple configuration, and the drive unit 20 can be driven smoothly.

[0068] As shown in Figure 4, the receiving portion 42 receives at least the portion of the connecting portion 23a (outer connecting portion) that is connected to the vibrating portion 21 on the movable portion 10 side of the two vibrating portions 21 to which the connecting portion 23a (outer connecting portion) is connected.

[0069] With the above configuration, when an impact is applied to the optical deflector 2 and the drive unit 20 attempts to be displaced downward, the rotational stress generated in the connecting part 23a connected to the vibrating part 21 on the movable part 10 side can be suppressed, and damage to the connecting part 23a can be reliably prevented.

[0070] As shown in Figure 4, the receiving portion 42 supports the entire connecting portion 23a (outer connecting portion).

[0071] With this configuration, when an impact is applied to the optical deflector 2 and the drive unit 20 attempts to be displaced downward, the entire connecting portion 23a is supported by the receiving portion 42, thus more reliably preventing damage to the connecting portion 23a.

[0072] As shown in Figure 2, the multiple connecting parts 23a, 23b, and 23c are thicker than the vibrating part 21.

[0073] This configuration increases the strength of the multiple connecting parts 23a, 23b, and 23c, thereby further suppressing damage to the drive unit 20.

[0074] As shown in Figures 5 and 6, the support substrate 40 is attached to the lower surface of the fixing part 30 by adhesive 50.

[0075] With this configuration, the support substrate 40 can be installed in relation to the fixing part 30 with a simple structure.

[0076] <Example of change 1> In the above embodiment, the receiving portion 42 had the shape shown in Figure 3, but it is not limited to this, and may have the shapes shown in Figures 11(a) to 12(b), for example.

[0077] In the modified example shown in Figure 11(a), the receiving portion 42 is provided below the portion of the connecting portion 23a that connects to the first vibrating portion, but not below the portion of the connecting portion 23a that connects to the second vibrating portion. For convenience, the positions of the connecting portions 23a, 23b, and 23c are shown by dashed lines in Figure 11(a).

[0078] As shown in Figures 9(a) and (b), the first vibrating part is the vibrating part 21 furthest from the movable part 10, or in other words, the vibrating part 21 that is further from the movable part 10 than the two vibrating parts 21 connected to the connecting part 23a. The second vibrating part is the vibrating part 21 adjacent to the first vibrating part, or in other words, the vibrating part 21 that is closer to the movable part 10 than the two vibrating parts 21 connected to the connecting part 23a.

[0079] In the modified example shown in Figure 11(a), the receiving portion 42 is provided at least below the connecting portion 23a, so when an impact is applied, the connecting portion 23a is supported by the receiving portion 42, and damage to the connecting portion 23a can be suppressed. However, as described above, if the receiving portion 42 is provided only below the portion of the connecting portion 23a that connects to the first vibrating portion, rotational stress may be generated in the portion of the connecting portion 23a that connects to the second vibrating portion when an impact is applied. Therefore, it is preferable that the receiving portion 42 be provided at least below the portion of the connecting portion 23a that connects to the second vibrating portion.

[0080] In the modified example shown in Figure 11(b), the receiving portion 42 is provided only below the portion of the connecting portion 23a that connects to the second vibrating portion, and not below the portion of the connecting portion 23a that connects to the first vibrating portion.

[0081] With this configuration, since the receiving portion 42 is provided below the portion of the connecting portion 23a that connects to the second vibrating portion, the rotational stress generated in the portion of the connecting portion 23a that connects to the second vibrating portion can be suppressed compared to the modified example in Figure 11(a).

[0082] In the modified example shown in Figure 12(a), the receiving portion 42 extends in the positive Y-axis direction compared to the modified example in Figure 11(a).

[0083] As explained with reference to Figures 9(a) and (b), since the first vibrating part does not deform from a state parallel to the XY plane to the negative side of the Z axis, the support part 42 may be formed below the first vibrating part, as shown in Figure 12(a). With this configuration, compared to the modified example in Figure 11(a), the strength of the support part 42 can be increased because the three sides of the support part 42 are connected to the fixing part 30.

[0084] In the modified example shown in Figure 12(b), the receiving portion 42 is located below the entire connecting portion 23a, compared to the modified example in Figure 12(a).

[0085] With this configuration, similar to the above embodiment, damage to the connecting portion 23a can be reliably prevented when the optical deflector 2 is subjected to impact, and the strength of the receiving portion 42 can be increased, similar to the modified example in Figure 12(a).

[0086] <Example of change 2> In the above embodiment, the adhesive 50 is arranged as shown in Figure 3, and the fixing part 30 and the support substrate 40 are bonded together. At this time, it is conceivable that the adhesive 50 placed between the fixing part 30 and the support substrate 40 may, due to the close contact between the fixing part 30 and the support substrate 40, protrude from the shaded area in Figure 3 in a direction parallel to the XY plane and flow into the area of ​​the receiving part 42 below the connecting part 23a. Therefore, it is preferable that the optical deflector 2 has a structure to suppress the flow of the adhesive 50 into the area of ​​the receiving part 42 below the connecting part 23a. This structure can be configured, for example, as shown in Figures 13(a) to 15(b).

[0087] In the modified example shown in Figure 13(a), openings G11 and G12 are formed, compared to the modified example in Figure 12(a).

[0088] Opening G11 is formed between the receiving portion 42 and opening 41a in the X-axis direction, and opening G12 is formed between the receiving portion 42 and opening 41a in the Y-axis direction. Openings G11 and G12 penetrate the support substrate 40 in the Z-axis direction.

[0089] As shown in Figure 13(b), the receiving portion 42 may be provided below the entire connecting portion 23a (outer connecting portion). Also, as shown in Figure 14(a), the opening G11 may be provided only in adjacent regions of the connecting portion 23a in the Y-axis direction. Furthermore, as shown in Figure 14(b), an opening G13 may be formed on the opposite side of the opening G12 in the Y-axis direction for the receiving portion 42.

[0090] In the modified example shown in Figure 15(a), a groove G2 is formed, compared to the modified example in Figure 12(b).

[0091] Groove G2 is a recess that is indented in the negative Z-axis direction from the upper surface of the support substrate 40. In plan view, groove G2 has an L-shape consisting of a portion extending in the X-axis direction and a portion extending in the Y-axis direction. In plan view, groove G2 is formed between the connecting portion 23a and the contour of the opening 41a which is located away from the movable portion 10 relative to the connecting portion 23a. In Figure 15(a), for convenience, the position of groove G2 is indicated by thick diagonal lines.

[0092] Furthermore, the portion of groove G2 extending in the Y-axis direction only needs to be provided in a portion adjacent to the connecting portion 23a in the Y-axis direction. For example, as shown in Figure 15(b), the portion of groove G2 extending in the Y-axis direction may be shorter than that shown in Figure 15(a). Alternatively, a projection G3 may be provided instead of groove G2. The projection G3 is a convex portion that protrudes from the upper surface of the support substrate 40 in the positive Z-axis direction, and in a plan view, it is formed in the same region as groove G2, for example.

[0093] In this modified example, the adhesive 50 is placed in a predetermined second region (for example, the shaded region in Figure 3) other than the first region of the receiving portion 42 below the connecting portion 23a (outer connecting portion) on the support substrate 40, and as shown in Figures 13(a) to 15(b), the light deflector 2 has openings G11, G12, G13, grooves G2 or protrusions G3 (structures) to suppress the adhesive 50 from flowing into the first region.

[0094] With this configuration, the flow of adhesive 50 into the first region of the receiving portion 42 below the connecting portion 23a (outer connecting portion) is suppressed, thereby preventing the receiving portion 42 from becoming adhered to the connecting portion 23a (outer connecting portion).

[0095] The structure for preventing the adhesive 50 from flowing into the first region of the receiving portion 42 below the connecting portion 23a is an opening G11, G12, G13, groove G2, or projection G3 formed between the first region and the second region of the support substrate 40.

[0096] With this configuration, the adhesive 50 can be prevented from flowing into the area of ​​the receiving portion 42 by simple processing such as forming openings G11, G12, G13, grooves G2, or protrusions G3 in the support substrate 40.

[0097] <Example of change 3> To prevent the adhesive 50 from flowing into the receiving portion 42 below the connecting portion 23a, a material that reduces wettability may be applied to the receiving portion 42 below the connecting portion 23a.

[0098] In the modified example shown in Figure 16(a), compared to the embodiment in Figure 3, a material 70 that reduces wettability is applied to the area of ​​the receiving portion 42 below the connecting portion 23a. In the modified example shown in Figure 16(a), in a plan view, the area of ​​the receiving portion 42 below the connecting portion 23a coincides with the area of ​​the connecting portion 23a.

[0099] In this modified example, the structure for preventing the adhesive 50 from flowing into the first region of the receiving portion 42 below the connecting portion 23a is the structure of the first region formed by applying a material 70 that reduces the wettability of the first region to the first region.

[0100] With this configuration, the flow of the adhesive 50 into the receiving portion 42 can be suppressed by a simple process such as applying a material 70 that reduces wettability.

[0101] The area to which material 70 is applied is not limited to the first area corresponding to the connecting portion 23a in a plan view. The area to which material 70 is applied does not overlap with the second area where the adhesive 50 is placed (the shaded area in Figure 3), and does not need to include the first area corresponding to the connecting portion 23a in a plan view. For example, as shown in Figure 16(b), it may be wider than the area in Figure 16(a).

[0102] <Other examples of changes> The openings, grooves, and protrusions shown in the above modification example 2 are not limited to being formed individually, but may also be formed in combination.

[0103] In the above embodiments and modified examples 1 and 2, the material that reduces wettability as shown in modified example 3 may be applied to the area of ​​the receiving portion 42 facing the lower surface of the connecting portion 23a.

[0104] In the above embodiment and its modifications, as shown in Figure 3, adhesive 50 is applied to the entire lower surface of the frame portion 31 of the fixing portion 30, thereby bonding the fixing portion 30 to the support substrate 40. However, the placement of the adhesive 50 may be limited to a portion of the lower surface of the frame portion 31 of the fixing portion 30, rather than the entire lower surface. For example, if the application of adhesive 50 is omitted near the receiving portion 42, it is possible to prevent the adhesive 50 from flowing into the receiving portion 42.

[0105] In the above embodiments and modified examples, the entire upper surface of the receiving portion 42 was parallel to the XY plane, but it is sufficient that at least the upper surface of the receiving portion 42 located below the connecting portion 23a is parallel to the XY plane.

[0106] In the above embodiments and modifications, the piezoelectric body 25 consisted only of a lower electrode layer 111, a piezoelectric layer 112, and an upper electrode layer 113, but other layers may be included between each layer.

[0107] In the above embodiments and modifications, as shown in Figures 8(a) and 8(b), a positive voltage V was alternately applied to the first group of piezoelectric elements 25 and the second group of piezoelectric elements 25, and the pair of drive units 20 were driven so that each vibrating part 21 deformed only in the upward direction, as shown in Figures 9(a) and 9(b). In contrast, if it is a problem that the lower surface of the connecting part 23a comes into contact with the receiving part 42 when the optical deflector 2 is driven, the waveform of the drive voltage shown in Figures 8(a) and 8(b) may be adjusted so that the lower surface of the connecting part 23a does not come into contact with the receiving part 42, and the control unit 301 may drive the pair of drive units 20 based on the adjusted waveform of the drive voltage. For example, the waveform of the drive voltage shown in Figures 8(a) and 8(b) may be adjusted to a waveform that is offset in the positive direction of the voltage.

[0108] In addition, the embodiments of the present invention can be modified in various ways as appropriate within the scope of the technical idea set forth in the claims.

[0109] (Note) The above description of embodiments discloses the following technologies.

[0110] (Technology 1) Driving element and The system comprises a support substrate that supports the aforementioned drive element, The aforementioned drive element is A movable part equipped with a reflective surface, The fixing part installed on the support substrate, The movable part rotates with respect to the pivot axis, and the drive unit is installed between the movable part and the fixed part, The aforementioned drive unit is Multiple vibrating parts, Multiple connecting parts are connected in a meandering manner, and each connecting part has a rib that protrudes downward to the height of the lower surface of the fixed part, The system comprises a piezoelectric body provided above the plurality of vibrating parts, The support substrate has a receiving portion formed therein for receiving the lower surface of the rib of the outermost connecting portion, which is furthest from the movable portion among the plurality of connecting portions. The movable part is rotated by driving the plurality of vibrating parts to bend only upward. A light deflector characterized by the following features.

[0111] In a configuration without a support section, if the optical deflector is subjected to an impact and the drive section is displaced excessively downward, the greatest stress is generated at the connection between the drive section and the fixed section, followed by the outermost connection section, which is furthest from the movable section among the multiple connection sections. In contrast, according to the above technology, when the optical deflector is subjected to an impact, the outer connection section is supported by the support section and does not displace substantially downward. Therefore, no great stress is generated at the outer connection section, nor at the connection section on the fixed section side relative to the outer connection section. This prevents damage to the drive section due to excessive downward displacement when the optical deflector is subjected to an impact.

[0112] Furthermore, when the movable part is driven, the multiple vibrating parts are driven to bend only upward, so the outer connecting part does not displace substantially downward (towards the receiving part). Therefore, even if the lower surface of the outer connecting part is supported by the receiving part, the receiving part does not obstruct the driving of the drive part when the movable part is driven. Consequently, even if a receiving part is provided, the drive part can be driven smoothly.

[0113] Furthermore, since the outer connecting portion does not substantially move downward when the movable part is driven, the receiving portion may be in contact with or close to the lower surface of the outer connecting portion, and it is not necessary to provide a gap of a specified size between the outer connecting portion and the receiving portion to allow the drive portion to move. As a result, the receiving portion can be simply constructed as a stopper to support the lower surface of the outer connecting portion.

[0114] Therefore, according to the above technology, with a simple configuration, damage to the drive unit when an impact is applied to the optical deflector can be prevented, and the drive unit can be driven smoothly.

[0115] (Technology 2) In the optical deflector described in Technology 1, The receiving portion receives at least the portion of the outer connecting portion that is connected to the vibrating portion on the movable side of the two vibrating portions connected by the outer connecting portion. A light deflector characterized by the following features.

[0116] According to this technology, when an impact is applied to the optical deflector and the drive unit attempts to displace downward, the rotational stress generated in the outer connecting part connected to the vibrating part on the movable side can be suppressed, thereby reliably preventing damage to the outer connecting part.

[0117] (Technology 3) In the optical deflector described in Technology 2, The receiving portion supports the entire outer connecting portion. A light deflector characterized by the following features.

[0118] According to this technology, when an impact is applied to the optical deflector and the drive unit attempts to be displaced downward, the entire outer connecting section is supported by the receiving section, thus more reliably preventing damage to the outer connecting section.

[0119] (Technology 4) In the optical deflector described in any one of the three technical specifications, The support substrate is attached to the lower surface of the fixing part with adhesive. A light deflector characterized by the following features.

[0120] This technology allows the support substrate to be installed in relation to the fixing part with a simple configuration.

[0121] (Technology 5) In the optical deflector described in Technology 4, The adhesive is placed in the support substrate in a predetermined second region other than the first region of the receiving portion below the outer connecting portion. The structure has a mechanism for preventing the adhesive from flowing into the first region. A light deflector characterized by the following features.

[0122] This technology prevents adhesive from flowing into the first region of the receiving portion below the outer connecting portion, thus preventing the receiving portion from becoming adhered to the outer connecting portion.

[0123] (Technology 6) In the optical deflector described in Technical 5, The structure is an opening, groove, or projection formed between the first region and the second region of the support substrate. A light deflector characterized by the following features.

[0124] This technology allows for the prevention of adhesive flow into the receiving area by simple processing such as forming openings, grooves, or protrusions in the support substrate.

[0125] (Technology 7) In the optical deflector described in Technology 5 or 6, The structure is a structure of the first region formed by applying a material that reduces the wettability of the first region to the first region. A light deflector characterized by the following features.

[0126] This technology allows for the prevention of adhesive flow into the receiving area through simple processes such as applying a material that reduces wettability.

[0127] (Technology 8) An optical deflector as described in any of Techniques 1 through 7, The system includes a control circuit that rotates the movable part by driving the plurality of vibrating parts to bend upward only, A light deflection device characterized by the following features.

[0128] This technology produces the same effect as the optical deflector described above. [Explanation of symbols]

[0129] 1. Driving element 2 Optical deflector 10 Moving parts 11 Reflective surface 20 Drive unit 21 Vibration section 23a Connecting part (outer connecting part) 23b, 23c connection part 25 Piezoelectric 30 Fixed part 40 Support substrate 42 Receiving part 50 Adhesives G11, G12, G13 opening (structure) G2 groove (structure) G3 protrusion (structure) R10 pivot axis

Claims

1. Driving element and The system comprises a support substrate that supports the aforementioned drive element, The aforementioned drive element is A movable part with a reflective surface, The fixing part installed on the support substrate, The movable part rotates with respect to the pivot axis, and the drive unit is installed between the movable part and the fixed part, The aforementioned drive unit is Multiple vibrating parts, Multiple connecting parts are connected in a meandering manner, and each connecting part has a rib that protrudes downward to the height of the lower surface of the fixed part, The system comprises a piezoelectric body provided above the plurality of vibrating parts, The support substrate has a receiving portion formed therein for receiving the lower surface of the rib of the outermost connecting portion, which is furthest from the movable portion among the plurality of connecting portions. The movable part is rotated by driving the plurality of vibrating parts to bend only upward. A light deflector characterized by the following features.

2. In the optical deflector according to claim 1, The receiving portion receives at least the portion of the outer connecting portion that is connected to the vibrating portion on the movable side of the two vibrating portions connected by the outer connecting portion. A light deflector characterized by the following features.

3. In the optical deflector according to claim 2, The receiving portion supports the entire outer connecting portion. A light deflector characterized by the following features.

4. In the optical deflector according to claim 1, The support substrate is attached to the lower surface of the fixing part with adhesive. A light deflector characterized by the following features.

5. In the optical deflector according to claim 4, The adhesive is placed in the support substrate in a predetermined second region other than the first region of the receiving portion below the outer connecting portion. The structure has a mechanism for preventing the adhesive from flowing into the first region. A light deflector characterized by the following features.

6. In the optical deflector according to claim 5, The structure is an opening, groove, or projection formed between the first region and the second region of the support substrate. A light deflector characterized by the following features.

7. In the optical deflector according to claim 5, The structure is a structure of the first region formed by applying a material that reduces the wettability of the first region to the first region. A light deflector characterized by the following features.

Images