Optical deflector, image projection device, head-up display, laser headlamp, head-mounted display, distance measuring device and moving body

Abstract

To suppress reduction of a resonance frequency that is generated when a mobile body is increased.SOLUTION: The optical deflector according to an embodiment of the present invention includes: a mobile unit; a supporting unit connected to the mobile unit at one end, the supporting unit elastically supporting the mobile unit; a driving beam connected to the supporting unit at another end, the driving beam deforming the supporting unit to rock the mobile body around a predetermined rocking axis; a connection unit for connecting the supporting unit and the driving beam to each other; and a supporting frame for supporting the driving beam by a fixing unit. The supporting unit has a supporting thick unit and the connection unit has a connection thick unit. The supporting thick unit and the connection thick unit are connected together.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to an optical deflector, an image projection device, a head-up display, a laser headlamp, a head-mounted display, a distance measuring device, and a moving object. [Background technology]

[0002] In recent years, with the advancement of micromachining technology that utilizes semiconductor manufacturing technology, there has been progress in the development of MEMS (Micro Electro Mechanical Systems) devices that are manufactured by microfabricating silicon or glass.

[0003] A MEMS device disclosed has a configuration including first and second actuators that oscillate a mirror portion (movable portion) around a first axis and a second axis that are perpendicular to each other, and drives the first actuator based on a drive signal having a frequency component near the resonant frequency related to the oscillating vibration of the mirror portion to oscillate and vibrate the mirror portion around the first axis, thereby scanning a light beam reflected by the mirror portion in a horizontal direction related to a raster scan (see, for example, Patent Document 1). Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the configuration of Patent Document 1, when the movable part such as the movable plate becomes large, the moment of inertia increases, and there is a concern that the resonance frequency of the optical deflector may decrease.

[0005] An object of the present invention is to suppress a decrease in resonance frequency that occurs when the moving part is made larger. [Means for solving the problem]

[0006] An optical deflector according to one aspect of the present invention includes a movable part, a support part having one end connected to the movable part and elastically supporting the movable part, a drive beam connected to the other end of the support part and causing the movable part to swing around a predetermined swing axis by deforming the support part, a connection part connecting the support part and the drive beam, and a support frame supporting the drive beam via a fixed part, A support thin portion and a support frame having a thickness that is thicker than the support thin portion and the same thickness as the support frame. Support thick part and, is provided at the connection portion. A connecting thin part and a supporting thick part having a thickness equal to that of the connecting thin part and being thicker than the connecting thin part. Thick connection part and, is provided, and the supporting thick portion and the connecting thick portion are connected to each other.

[0007] An optical deflector according to one aspect of the present invention includes a movable section, a support section having one end connected to the movable section and supporting the movable section, a drive beam connected to the other end of the support section and causing the movable section to swing around a predetermined swing axis by deforming the support section, a connection section connecting the support section and the drive beam, and a support frame supporting the drive beam via a fixed section, wherein the connection section is provided with a thick connection section, and the drive beam includes: A driving thin portion and a driving frame having a thickness equal to that of the supporting frame and thicker than the driving thin portion. A first driving thick portion and a second driving thick portion are provided, and the first driving thick portion and the second driving thick portion extend in a direction perpendicular to the oscillation axis. Effect of the Invention

[0008] According to the present invention, it is possible to suppress a decrease in resonance frequency that occurs when the movable part is enlarged. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a plan view illustrating the movable device according to the first embodiment. [Diagram 2] FIG. 2 is an end view of the moveable device along a second axis of FIG. 1. [Diagram 3] FIG. 2 is an end view of the movable device taken along the line PP in FIG. 1; [Figure 4] 11 is a plan view illustrating a movable device according to a modified example of the first embodiment. FIG. [Diagram 5]FIG. 2 is a top view illustrating an example of a configuration around a torsion bar. [Figure 6] FIG. 4 is a bottom view illustrating an example of the configuration around the torsion bar. [Figure 7] 11A and 11B are diagrams illustrating examples of configurations for suppressing abrupt changes in shape. [Figure 8] FIG. 11 is a diagram showing the relationship between the diameter of the mirror portion, the moment of inertia, and the resonance frequency. [Figure 9] FIG. 13 is a bottom view of the periphery of a torsion bar of a movable device according to a first modified example. [Figure 10] FIG. 11 is a bottom view of the periphery of a torsion bar of a movable device according to a second modified example. [Figure 11] FIG. 13 is a diagram showing the offset of the torsion bar twisting central axis relative to the center of the mirror portion. [Figure 12] 12A and 12B are diagrams showing an example of the relationship between frequency and oscillation angle, in which FIG. 12A is a diagram showing the case where the resonant frequency of the mirror part is higher than the resonant frequency of the first piezoelectric driving part, and FIG. 12B is a diagram showing the case where the resonant frequency of the mirror part is lower than the resonant frequency of the first piezoelectric driving part. [Figure 13] 13A is a diagram of the bending mode shape of the first piezoelectric driver and the twisting mode shape of the torsion bar, and FIG. 13B is a diagram of the twisting mode shape of the torsion bar. FIG. [Figure 14] FIG. 11 is a bottom view showing a first example of a movable device according to a second embodiment. [Figure 15] FIG. 11 is a bottom view showing a second example of the movable device according to the second embodiment. [Figure 16] 16A and 16B are diagrams showing an example of the relationship between the offset, the length of the first piezoelectric driving part, and the oscillation center position, where FIG. 16(a) is a diagram showing a case in which none of the driving thick part, the first driving thick part, and the second driving thick part is provided in the first piezoelectric driving part, and FIG. 16(b) is a diagram showing this embodiment. [Figure 17] 13 is a diagram showing an example of the relationship between the offset, the length of a first piezoelectric driving part, and surface deformation. FIG. [Figure 18] 13A and 13B are diagrams illustrating modified examples of the surface of the mirror portion. [Figure 19] FIG. 11 is a bottom view showing a third example of the movable device according to the second embodiment. [Figure 20] FIG. 13 is a bottom view showing a fourth example of the movable device according to the second embodiment. [Figure 21] 1 is a schematic diagram of an example optical scanning system. [Figure 22] FIG. 2 is a diagram illustrating a hardware configuration of an example of an optical scanning system. [Diagram 23] FIG. 2 is a functional block diagram of an example of a control device. [Figure 24] 13 is a flowchart of an example of a process related to the optical scanning system. [Diagram 25] 1 is a schematic diagram of an example of an automobile equipped with a head-up display device. [Figure 26] 1 is a schematic diagram of an example of a head-up display device. [Figure 27] 1 is a schematic diagram of an example of an image forming apparatus equipped with an optical writing device. [Figure 28] FIG. 1 is a schematic diagram of an example of an optical writing device. [Figure 29] 1 is a schematic diagram of an example of an automobile equipped with a laser radar device. [Diagram 30] FIG. 11 is a schematic diagram of another example of an automobile equipped with a laser radar device. [Diagram 31] FIG. 1 is a schematic diagram of an example of a laser radar device. [Diagram 32] FIG. 1 is a schematic diagram of an example laser headlamp. [Diagram 33] FIG. 1 is a perspective view of the appearance of an example of a head mounted display. [Diagram 34] FIG. 1 is a diagram illustrating a partial configuration of a head mounted display. [Diagram 35] 1 is a schematic diagram of an example of a packaged movable device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and duplicated explanations may be omitted.

[0011] In the following description of the embodiment, rotation, swinging, and movement are synonymous. Among the directions indicated by arrows, the stacking direction of each layer in the piezoelectric drive unit and the like is the Z direction, and the directions perpendicular to the Z direction in a plane perpendicular to the Z direction are the X direction and the Y direction. Planar view refers to viewing an object from the Z direction.

[0012] Additionally, the direction in which the arrow points in the X direction is denoted as the +X direction and the opposite direction of the +X direction is denoted as the -X direction, the direction in which the arrow points in the Y direction is denoted as the +Y direction and the opposite direction of the +Y direction is denoted as the -Y direction, the direction in which the arrow points in the Z direction is denoted as the +Z direction and the opposite direction of the +Z direction is denoted as the -Z direction. However, these do not limit the orientation of the optical deflector, and the orientation of the optical deflector is arbitrary.

[0013] Hereinafter, the embodiment will be described by taking an optical deflector as an example of the movable device.

[0014] [First embodiment] <Configuration example of movable device 13> The configuration of the movable device 13 according to the first embodiment will be described with reference to Fig. 1 to Fig. 3. Fig. 1 is a plan view illustrating the movable device 13. Fig. 2 is an end view of the movable device 13 taken along the second axis in Fig. 1. Fig. 3 is an end view of the movable device 13 taken along the cutting line PP in Fig. 1.

[0015] As shown in FIG. 1, the movable device 13 includes a mirror portion 101, first drive portions 110a and 110b, a first support frame 120, second drive portions 130a and 130b, a second support frame 140, an electrode connection portion 150, and a control device 11.

[0016] The mirror unit 101 has a reflecting surface 14 and is an example of a movable unit that reflects incident light. Each of the first driving units 110a and 110b is connected to the mirror unit 101 and swings the mirror unit 101 around a first axis parallel to the Y axis. The support frame 120 supports the mirror unit 101 and the first driving units 110a and 110b.

[0017] The second driving units 130a and 130b are connected to the first support frame 120 and swing the mirror unit 101 and the first support frame 120 around a second axis parallel to the X-axis. The second support frame 140 supports the second driving units 130a and 130b. The electrode connection unit 150 is electrically connected to the first driving units 110a and 110b, the second driving units 130a and 130b, and the control device 11.

[0018] The movable device 13 is formed, for example, by forming a single SOI (Silicon On Insulator) substrate by etching or the like, and forming the reflecting surface 14, first piezoelectric driving units 112a and 112b, second piezoelectric driving units 131a-131f and 132a-132f, electrode connection unit 150, etc., on the formed substrate, so that each component is integrally formed. Note that the formation of each of the above components may be performed after or during the formation of the SOI substrate.

[0019] 2, the SOI substrate on which the movable device 13 is formed includes a silicon support layer 161 made of single crystal silicon (Si), a silicon oxide layer 162 formed on the silicon support layer 161 (on the +Z direction side), and a silicon active layer 163 made of single crystal silicon formed on the silicon oxide layer 162. The silicon oxide layer 162 can also be called a BOX (Buried Oxide) layer.

[0020] Since the silicon active layer 163 has a smaller thickness in the Z direction than in the X or Y direction, a member constituted only by the silicon active layer 163 functions as an elastic portion having elasticity.

[0021] The SOI substrate does not necessarily have to be flat, and may have a curvature, etc. Also, the material used to form the movable device 13 is not limited to the SOI substrate, as long as it can be integrally molded by etching or the like and can be partially made elastic.

[0022] The mirror section 101 includes, for example, a circular mirror section base 102 and a reflecting surface 14 formed on the +Z side surface of the mirror section base. The mirror section base 102 includes, for example, a silicon active layer 163. The reflecting surface 14 includes, for example, a metal thin film including aluminum, gold, silver, or the like.

[0023] A movable thick portion 103 for reinforcing the mirror portion is formed on the -Z side surface of the mirror portion base 102. The movable thick portion 103 includes, for example, a silicon support layer 161 and a silicon oxide layer 162, and can suppress distortion of the reflecting surface 14 caused by movement.

[0024] As shown in FIG. 1, the first actuators 110a and 110b include torsion bars 111a and 111b and first piezoelectric actuators 112a and 112b.

[0025] Each of the torsion bars 111a and 111b has one end connected to the mirror portion 101, and is an example of a support portion that extends in the first axial direction and elastically supports the mirror portion 101.

[0026] One end of each of the first piezoelectric actuators 112a and 112b is connected to the torsion bars 111a and 111b, and is an example of an actuator beam that deforms the torsion bars 111a and 111b to cause the mirror section 101 to oscillate around a first axis. The first axis is an example of a predetermined oscillation axis. The other end of each of the first piezoelectric actuators 112a and 112b is connected to an inner periphery of the first support frame 120. The first actuators 110a and 110b also include detection piezoelectric elements 160a and 160b.

[0027] 3, the torsion bars 111a and 111b include a silicon active layer 163. In addition, the first piezoelectric driving parts 112a and 112b have a lower electrode 301, a piezoelectric part 302, and an upper electrode 303 laminated in this order on the +Z side surface of the silicon active layer 163, which is an elastic part. The upper electrode 303 and the lower electrode 301 include, for example, gold (Au) or platinum (Pt). The piezoelectric part 302 includes, for example, PZT (lead zirconate titanate), which is a piezoelectric material.

[0028] As shown in FIGS. 1 to 3, the first support frame 120 is a rectangular support body that is composed of a silicon support layer 161, a silicon oxide layer 162, and a silicon active layer 163 and is formed so as to surround the mirror section 101.

[0029] The second driving units 130a and 130b include a plurality of second piezoelectric driving units 131a-131f and 132a-132f that are connected in a folded manner. One end of the second driving units 130a and 130b is connected to the outer periphery of the first support frame 120, and the other end is connected to the inner periphery of the second support frame 140.

[0030] The connection point between the second driving unit 130a and the first support frame 120 and the connection point between the second driving unit 130b and the first support frame 120 are point symmetrical with respect to the center of the reflecting surface 14. In addition, the connection point between the second driving unit 130a and the second support frame 140 and the connection point between the second driving unit 130b and the second support frame 140 are point symmetrical with respect to the center of the reflecting surface 14.

[0031] 2, in the second driving units 130a and 130b, a lower electrode 201, a piezoelectric unit 202, and an upper electrode 203 are laminated in this order on the +Z side surface of a silicon active layer 163, which is an elastic unit. The upper electrode 203 and the lower electrode 201 include, for example, gold (Au) or platinum (Pt). The piezoelectric unit 202 includes, for example, PZT (lead zirconate titanate), which is a piezoelectric material.

[0032] 1 and 2, the second support frame 140 includes a silicon support layer 161, a silicon oxide layer 162, and a silicon active layer 163. The second support frame 140 is a rectangular support formed to surround the mirror unit 101, the first drive units 110a and 110b, the first support frame 120, and the second drive units 130a and 130b.

[0033] The electrode connection part 150 is formed on the surface on the +Z side of the second support frame 140, and is electrically connected to the first piezoelectric driving parts 112a and 112b, the upper electrodes 203 and lower electrodes 201 of the second piezoelectric driving parts 131a to 131f, and the control device 11 via electrode wiring such as aluminum (Al). A signal voltage is applied to the lower electrode 201, and the upper electrode 203 is grounded (GND).

[0034] The upper electrode 203 or the lower electrode 201 may be directly connected to the electrode connector 150, or may be indirectly connected by connecting the electrodes together, for example.

[0035] In this embodiment, an example has been described in which the piezoelectric portion 202 is formed only on one surface (the surface on the +Z side) of the silicon active layer 163, which is the elastic portion. However, the piezoelectric portion 202 may be provided on another surface (for example, the surface on the -Z side) of the elastic portion, or may be provided on both one surface and the other surface of the elastic portion.

[0036] In addition, as long as the mirror unit 101 can be driven around the first axis or the second axis, the shape of each component is not limited to the shape of the embodiment. For example, the torsion bars 111a and 111b and the first piezoelectric drive units 112a and 112b may have a shape with a curvature.

[0037] Furthermore, an insulating layer made of a silicon oxide film may be formed on at least one of the +Z side surface of the upper electrode 303 of the first driving units 110a and 110b, the +Z side surface of the first support frame, the +Z side surface of the upper electrode 203 of the second driving units 130a and 130b, and the +Z side surface of the second support frame.

[0038] In this case, electrode wiring is provided on the insulating layer, and the insulating layer is partially removed or not formed as an opening only at the connection spot where the upper electrode 203, the upper electrode 303, the lower electrode 201, or the lower electrode 301 is connected to the electrode wiring. This increases the design freedom of the first driving units 110a and 110b, the second driving units 130a and 130b, and the electrode wiring, and can suppress short circuits due to contact between electrodes. The silicon oxide film also functions as an anti-reflection material.

[0039] A detection piezoelectric element 160a for detecting elastic deformation of the first driving section 110a is provided adjacent to the first piezoelectric driving section 112a. A detection piezoelectric element 160b for detecting elastic deformation of the first driving section 110b is provided adjacent to the first piezoelectric driving section 112b.

[0040] The first piezoelectric driving unit 112a is provided in the first driving unit 110a and deforms the first driving unit 110a in response to an applied driving voltage. The first piezoelectric driving unit 112b is provided in the first driving unit 110b and deforms the first driving unit 110b in response to an applied driving voltage.

[0041] The detection piezoelectric element 160a generates a detection signal by the piezoelectric effect in response to the deformation of the first driving unit 110a, and outputs the detection signal to the control device 11 via the electrode connecting unit 150. The detection piezoelectric element 160b generates a detection signal by the piezoelectric effect in response to the deformation of the first driving unit 110b, and outputs the detection signal to the control device 11 via the electrode connecting unit 150.

[0042] <Control by control device 11> Next, the control by the control device 11 that drives the first drive units 110a and 110b of the movable device will be described.

[0043] When a positive or negative voltage is applied in the polarization direction to the piezoelectric portion 302 of the first driving portions 110a and 110b and the piezoelectric portion 202 of the second driving portions 130a and 130b, deformation (e.g., expansion and contraction) occurs in proportion to the potential of the applied voltage, thereby exerting the so-called inverse piezoelectric effect. The first driving portions 110a and 110b and the second driving portions 130a and 130b move the mirror portion 101 by utilizing the inverse piezoelectric effect.

[0044] In this case, the angle formed by the XY plane and the reflecting surface 14 when the reflecting surface 14 of the mirror section 101 is tilted in the +Z direction or the -Z direction with respect to the XY plane is called the deflection angle. The +Z direction is a positive deflection angle, and the -Z direction is a negative deflection angle.

[0045] In the first driving sections 110a and 110b, when a driving voltage is applied in parallel to the piezoelectric sections 302 of the first piezoelectric driving sections 112a and 112b via the upper electrode 303 and the lower electrode 301, the respective piezoelectric sections 302 are deformed.

[0046] The first piezoelectric actuators 112a and 112b are bent and deformed by the deformation of the piezoelectric section 302. As a result, a driving force about the first axis acts on the mirror section 101 via the twist of the two torsion bars 111a and 111b, and the mirror section 101 swings about the first axis. The driving voltage applied to the first actuators 110a and 110b is controlled by the control device 11.

[0047] The control device 11 applies a driving voltage having a predetermined sinusoidal waveform in parallel to the first piezoelectric driving units 112a and 112b of the first driving units 110a and 110b, so that the mirror unit 101 can be moved around the first axis at a period of the driving voltage having a predetermined sinusoidal waveform.

[0048] For example, when the frequency of the driving voltage is set to approximately 20 kHz, which is similar to the resonant frequency of the torsion bars 111a and 111b, the mirror portion 101 can be made to resonate at approximately 20 kHz by utilizing the mechanical resonance caused by the twisting of the torsion bars 111a and 111b.

[0049] Furthermore, the control device 11 can control the oscillation of the first drive sections 110a and 110b based on information about the oscillation of the first drive sections 110a and 110b acquired based on the detection signals output by the detection piezoelectric elements 160a and 160b, respectively.

[0050] <Modification of the first embodiment> 1, the movable device 13 according to this embodiment is of a cantilever type in which the first piezoelectric drive units 112a and 112b extend from the torsion bars 111a and 111b in the +X direction. However, the present invention is not limited to this as long as the mirror unit 101 can be oscillated by the piezoelectric unit 202 to which a drive voltage is applied. For example, the movable device may be of a double-supported type.

[0051] Here, Fig. 4 is a plan view illustrating a movable device 13a according to a modified example of the first embodiment. The same components as those of the movable device 13 are denoted by the same reference numerals, and duplicated explanations are omitted. As shown in Fig. 4, the movable device 13a has first driving units 210a and 210b.

[0052] The first driving portion 210a has a torsion bar 211a, a first piezoelectric driving portion 212a extending from the torsion bar 211a in the +X direction, and a first piezoelectric driving portion 212c extending from the torsion bar 211a in the -X direction.

[0053] The first driving section 210b has a torsion bar 211b, a first piezoelectric driving section 212b extending from the torsion bar 211b in the +X direction, and a first piezoelectric driving section 212d extending from the torsion bar 211b in the -X direction.

[0054] The embodiment can also be applied to such a double-supported type movable device 13a.

[0055] <Details of the configuration around the torsion bars 111a and 111b> Next, the configuration around the torsion bars 111a and 111b will be described in detail with reference to Fig. 5 and Fig. 6. Fig. 5 is a top view showing an example of the configuration around the torsion bars 111a and 111b, as viewed from the +Z direction. Fig. 6 is a bottom view showing an example of the configuration around the torsion bars 111a and 111b, as viewed from the -Z direction.

[0056] 5 and 6, one end of each of the torsion bars 111a and 111b is connected to both ends of the mirror section 101 along the Y direction, and elastically supports the mirror section 101. The other end of the torsion bar 111a is connected to one end of the first piezoelectric driving section 112a via a connecting section 113a. The other end of the torsion bar 111b is connected to one end of the first piezoelectric driving section 112b via a connecting section 113b. The other ends of each of the first piezoelectric driving sections 112a and 112b are supported by the first support frame 120 via a fixing section 121.

[0057] The mirror section 101 is oscillated by using the torsion bars 111a and 111b at a frequency of, for example, 20 kHz. As an example, the diameter of the reflecting surface 14 is 1 mm, the thickness of the silicon active layer 163 is approximately 50 μm, and the width of the torsion bars 111a and 111b along the X direction is approximately 50 μm. It is preferable that the aspect ratio (width / thickness) of the cross section of the torsion bars 111a and 111b is approximately 1.

[0058] 6, a thick support portion 114a is provided on the surface (hereinafter referred to as the lower surface) on the -Z direction side of the torsion bar 111a. A thick support portion 114b is provided on the lower surface of the torsion bar 111b. The thick support portions 114a and 114b are made of a silicon support layer 161 formed on the lower surface of the silicon active layer 163 in the torsion bars 111a and 111b, and are thicker than the portions of the torsion bars 111a and 111b made only of the silicon active layer 163.

[0059] The width of the thick support portion 114a in the X direction is formed to be slightly narrower than the width of the torsion bar 111a in the X direction, which allows for the misalignment of the masks used to form the silicon active layer 163 and the silicon support layer 161 during the manufacture of the movable device 13.

[0060] Further, a movable thick portion 103 is formed on the lower surface of the mirror portion 101. The movable thick portion 103 is composed of a silicon support layer 161 formed on the lower surface of the silicon active layer 163 in the mirror portion 101, and is thicker than the portion of the mirror portion 101 composed only of the silicon active layer 163. The movable thick portion 103 suppresses deformation of the mirror portion 101 when the mirror portion 101 oscillates, and functions as a reinforcing rib for keeping the reflecting surface 14 flat.

[0061] Furthermore, a thick connection portion 115a is provided on the lower surface of the connection portion 113a, and a thick connection portion 115b is provided on the lower surface of the connection portion 113b. The thick connection portions 115a and 115b are formed of a silicon support layer 161 formed on the lower surface of the silicon active layer 163 in the connection portions 113a and 115b, and are thicker than the portions of the connection portions 113a and 113b that are formed only of the silicon active layer 163.

[0062] Here, the movable thick portion 103 and the supporting thick portion 114a are connected, and the movable thick portion 103 and the supporting thick portion 114a are connected. Also, the supporting thick portion 114a and the connecting thick portion 115a are connected, and the supporting thick portion 114b and the connecting thick portion 115b are connected. "Connected" means that they are continuously formed so that the thicknesses are approximately equal.

[0063] Since the movable thick portion 103 is connected to each of the supporting thick portions 114a and 114b, there is no portion where the thickness changes suddenly between the movable thick portion 103 and each of the supporting thick portions 114a and 114b.

[0064] Similarly, because support thick portion 114a and connection thick portion 115a are connected, there is no portion where the thickness changes suddenly between support thick portion 114a and connection thick portion 115a. Also, because support thick portion 114b and connection thick portion 115b are connected, there is no portion where the thickness changes suddenly between support thick portion 114b and connection thick portion 115b.

[0065] As a result, when the mirror portion 101 is oscillated, stress occurring in a portion where the thickness changes suddenly is suppressed.

[0066] Furthermore, the width Wa1 along the first axis of the portion of the connection portion 113a close to the torsion bar 111a is wider than the width Wa2 along the first axis of the portion of the connection portion 113a far from the torsion bar 111a. Similarly, the width Wb1 along the first axis of the portion of the connection portion 113b close to the torsion bar 111b is wider than the width Wb2 along the first axis of the portion of the connection portion 113b far from the torsion bar 111a. This configuration improves the rigidity of the torsion bars 111a and 111b.

[0067] In addition, it is preferable to suppress abrupt changes in shape as much as possible in the portion where each thick portion is connected to another. Fig. 7 is a diagram showing an example of a configuration for suppressing abrupt changes in shape. Fig. 7 is an enlarged view of the portion where the movable thick portion 103 and the supporting thick portion 114a are connected. As shown in region A of Fig. 7, it is preferable that the connecting portion between the movable thick portion 103 and the supporting thick portion 114a is smoothly connected at an obtuse angle, not at an acute angle.

[0068] <Effects of the movable device 13> Next, the function and effect of the movable device 13 will be described.

[0069] In a movable device including a support such as a torsion bar, in order to increase the oscillation frequency using a large mirror, it is preferable to increase the rotational rigidity of the support. In addition, a two-layer silicon wafer such as an SOI substrate is used in a typical movable device. When oscillating in two axial directions that are approximately perpendicular to each other, it is preferable that the support that oscillates around the first axis and the second drive units such as the second drive units 130a and 130b that oscillate around the second axis have the same substrate thickness.

[0070] It is sometimes difficult to optimize the thickness because a thicker thickness is preferable to increase the rotational rigidity of the support unit, and a thinner thickness is preferable to increase the drive sensitivity of the second drive unit. Note that drive sensitivity refers to the oscillation angle per unit voltage.

[0071] Here, Fig. 8 is a diagram showing the relationship between the diameter of the mirror part, the moment of inertia, and the resonance frequency. As shown in Fig. 8, as the mirror part becomes larger, the moment of inertia increases rapidly. If the torsional rigidity (rotational rigidity) of the torsion bar remains the same, the resonance frequency decreases, so in order to maintain the resonance frequency, it is necessary to increase the torsional rigidity in proportion to the moment of inertia.

[0072] To increase the torsional rigidity of the torsion bar, the width and thickness of the torsion bar can be increased and the length shortened. However, increasing the thickness also increases the thickness of the second drive unit, increasing the moment of inertia, lowering the resonance frequency and decreasing the drive sensitivity. Also, the shorter the length of the torsion bar, the larger the twist angle per unit length becomes, so the fracture stress is reached at a small swing angle, and the fracture limit angle becomes smaller.

[0073] If the width of the torsion bar is increased to increase the fracture limit angle, the width of the torsion bar may become larger than the diameter of the mirror depending on the diameter of the mirror and the resonant frequency, and the layout may not be valid. Even if the layout is valid, the aspect ratio will be very large.

[0074] In addition, if the width of the torsion bar is widened, the mirror part is pulled at the connection part with the torsion bar, which increases the deformation of the mirror surface. In addition, if the cross-sectional aspect ratio of the torsion bar is large, the fracture stress increases and the nonlinearity between the oscillation angle and the driving voltage becomes large, making the behavior unstable. Furthermore, in the case of a cantilever support structure, it becomes difficult to generate a moment due to the offset.

[0075] The movable device 13 according to this embodiment includes a mirror section 101 (movable section), and torsion bars 111a and 111b (support sections) that are connected to the mirror section 101 at one end and support the mirror section 101. The movable device 13 also includes first piezoelectric actuators 112a and 112b (drive beams) that are connected to the other ends of the torsion bars 111a and 111b, respectively, and that deform the torsion bars 111a and 111b to cause the mirror section 101 to oscillate around a first axis (a predetermined oscillation axis).

[0076] The movable device 13 also has a connection portion 113a that connects the torsion bar 111a and the first piezoelectric driving portion 112a, a connection portion 113b that connects the torsion bar 111b and the first piezoelectric driving portion 112b, and a first support frame (support frame) that supports the first piezoelectric driving portions 112a and 112b via a fixed portion 121.

[0077] The torsion bar 111a is provided with a supporting thick portion 114a, the torsion bar 111b is provided with a supporting thick portion 114b, the connecting portion 113a is provided with a connecting thick portion 115a, and the connecting portion 113b is provided with a connecting thick portion 115b. The supporting thick portion 114a and the connecting thick portion 115a, and the supporting thick portion 114b and the connecting thick portion 115b are each connected to each other.

[0078] By providing the torsion bars 111a and 111b with the thick supporting portions 114a and 114b, the torsional rigidity (rotational rigidity) of the torsion bars 111a and 111b is increased, and a high resonance frequency can be obtained with the large mirror portion 101.

[0079] Furthermore, by compensating for the thickness of the torsion bars 111a and 111b with the thick support portions 114a and 114b made of the silicon support layer 161, the thickness of the silicon active layer 163 can be made thin, thereby ensuring high drive sensitivity of the second drive portions 130a and 130b.

[0080] In addition, the supporting thick portion 114a is connected to the connecting thick portion 115a, and the supporting thick portion 114b is connected to the connecting thick portion 115b. In addition, the movable thick portion 103 is connected to the supporting thick portions 114a and 114b. This makes it possible to suppress abrupt changes in shape, thereby suppressing stress concentration. As a result, the fracture limit angle of the torsion bars 111a and 111b can be increased.

[0081] In this embodiment, the width Wa1 along the first axis of the connection portion 113a close to the torsion bar 111a is wider than the width Wa2 along the first axis of the connection portion 113a far from the torsion bar 111a. Similarly, the width Wb1 along the first axis of the connection portion 113b close to the torsion bar 111b is wider than the width Wb2 along the first axis of the connection portion 113b far from the torsion bar 111a.

[0082] This configuration can improve the rigidity of the torsion bars 111a and 111b. In addition, the torsional rigidity of the torsion bars 111a and 111b can be improved, and a decrease in the resonance frequency when the mirror portion 101 is enlarged can be suppressed.

[0083] Furthermore, since the silicon active layer 163 of the torsion bars 111a and 111b and the silicon support layer 161 are bonded by the silicon oxide layer 162, insufficient bonding strength may cause the silicon active layer 163 and the silicon support layer 161 to peel off. By making the width Wa1 wider than the width Wa2 and making the width Wb1 wider than the width Wb2, the bonding strength can be increased, and therefore the silicon active layer 163 and the silicon support layer 161 can be prevented from peeling off.

[0084] <Modification> Here, FIG. 9 is a bottom view of the periphery of torsion bars 1111a and 111b of a movable device 13a according to the first modified example.

[0085] If the mirror portion 101 is large and the resonant frequency is high, damage may occur at the connection portion 113a or 113b when the mirror portion 101 swings at a large angle.

[0086] In contrast, in the movable device 13a, the first piezoelectric driving part 112a is provided with a driving thick part 116a, which is connected to the connecting thick part 115a. The first piezoelectric driving part 112b is provided with a driving thick part 116b, which is connected to the connecting thick part 115b. The connecting thick parts 115a and 115b each extend in the direction of the fixed part 121.

[0087] The driving thick portions 116a and 116b are composed of a silicon support layer 161 formed on the underside of the silicon active layer 163 in the first piezoelectric driving portions 112a and 112b, and are thicker than the portions composed only of the silicon active layer 163 in the first piezoelectric driving portions 112a and 112b.

[0088] This configuration increases the mechanical strength of the connection parts 113a and 113b, making it possible to prevent breakage at the connection parts 113a and 113b. In addition, by suppressing a sudden change in thickness between the driving thick part 116b and the connection thick part 115b, stress concentration can be suppressed and the breakage limit angle can be increased.

[0089] Furthermore, by providing the driving thick parts 116a and 116b extending in the direction in which the deformation amount changes during oscillation in the first piezoelectric driving parts 112a and 112b, i.e., in the direction substantially perpendicular to the first axis, the rigidity of the first piezoelectric driving parts 112a and 112b can be increased. As a result, the resonance frequency of the bending mode of the first piezoelectric driving parts 112a and 112b can be increased to the vicinity of the resonance frequency of the mirror part 101, and the bending mode of the first piezoelectric driving parts 112a and 112b and the torsional mode of the mirror part 101 are coupled, thereby increasing the driving sensitivity.

[0090] In addition, in the movable device 13a, an L-shaped configuration has been exemplified in which the connecting thick portions 115a and 115b are connected at the Y-direction ends of the supporting thick portions 114a and 114b, and the connecting thick portions 115a and 115b extend toward the fixed portion 121 in a direction approximately perpendicular to the extension direction of each of the supporting thick portions 114a and 114b, but this is not limited to the above.

[0091] For example, a T-shaped configuration may be used in which the connecting thick portions 115a and 115b are connected at a position closer to the mirror portion 101 than the ends of the supporting thick portions 114a and 114b in the Y direction, and the connecting thick portions 115a and 115b extend toward the fixed portion 121 in a direction approximately perpendicular to the directions in which the supporting thick portions 114a and 114b extend. By forming the connecting thick portions 115a and 115b in a T-shape, the rigidity can be further improved and a decrease in the resonant frequency can be further suppressed.

[0092] Next, FIG. 10 is a bottom view of the periphery of torsion bars 111a and 111b of a movable device 13b according to a second modified example.

[0093] In the movable device 13b, a width Wa1 along the first axis of a portion of the connecting portion 113a close to the torsion bar 111a is wider than a width Wa2 along the first axis of a portion of the connecting portion 113a far from the torsion bar 111a. Similarly, a width Wb1 along the first axis of a portion of the connecting portion 113b close to the torsion bar 111b is wider than a width Wb2 along the first axis of a portion of the connecting portion 113b far from the torsion bar 111a.

[0094] In this way, even in the configuration in which the driving thick portions 116a and 116b are provided, by making the width Wa1 wider than the width Wa2 and making the width Wb1 wider than the width Wb2, the torsional rigidity of the torsion bars 111a and 111b can be improved. Also, the silicon active layer 163 and the silicon support layer 161 in the torsion bars 111a and 111b can be prevented from peeling off.

[0095] [Second embodiment] Next, a movable device 13c according to a second embodiment will be described. Note that the same components as those in the first embodiment are given the same reference numerals, and duplicated descriptions will be omitted as appropriate.

[0096] The movable device 13c has a cantilever support structure that supports the torsion bars 111a and 111b from one side, and by offsetting the torsional central axes of the torsion bars 111a and 111b from the center of the mirror section 101, the amplitude of the first piezoelectric drive sections 112a and 112b is converted into a moment to oscillate the mirror section 101.

[0097] Fig. 11 is a diagram for explaining the offset of the torsion central axis of the torsion bar 111a with respect to the center of the mirror section 101. In Fig. 11, G indicates the center of gravity of the mirror section 101, H indicates the torsion central axis of the torsion bar 111a, and ΔS indicates the offset. By applying a voltage to the piezoelectric section 302, distortion occurs in the direction of the arrow σ. As a result, the tips of the first piezoelectric drive sections 112a and 112b and the torsion bar oscillate by ΔZ in the Amp direction. As a result, a moment M is generated, and the mirror section 101 oscillates at an amplitude angle θ.

[0098] By setting the bending mode resonance frequency of the first piezoelectric driving parts 112a and 112b close to the oscillation mode resonance frequency of the mirror part 101 (the twisting mode resonance frequency of the torsion bars 111a and 111b), the oscillation angle of the mirror part 101 becomes large, and a large oscillation angle can be obtained with a low driving voltage.

[0099] Fig. 12 is a diagram showing an example of the relationship between frequency and oscillation angle, Fig. 12(a) shows a case where the torsion-twisting mode resonance frequency is higher than the bending mode resonance frequency of the first piezoelectric driving parts 112a and 112b, and Fig. 12(b) shows a case where the torsion-twisting mode resonance frequency is lower than the bending mode resonance frequency of the first piezoelectric driving parts 112a and 112b.

[0100] In Fig. 12(a), 301 indicates the bending mode resonance frequency of the first piezoelectric actuators 112a and 112b, and 302 indicates the torsion-twisting mode resonance frequency. In Fig. 12(b), 303 indicates the torsion-twisting mode resonance frequency, and 304 indicates the bending mode resonance frequency of the first piezoelectric actuators 112a and 112b. In either case, a large rocking angle can be obtained by driving the mirror at the torsion twisting mode resonance frequency.

[0101] Fig. 13 is a diagram showing the shapes of the bending mode of the first piezoelectric actuators 112a and 112b and the torsion mode of the torsion bars 111a and 111b. Fig. 13(a) shows the bending mode shapes of the first piezoelectric actuators 112a and 112b, and Fig. 13(b) shows the torsion mode shapes of the torsion bars 111a and 111b.

[0102] Here, when the mirror section 101 becomes large, the mass of the tips of the first piezoelectric driving sections 112a and 112b increases, and the resonance frequency of the bending mode of the first piezoelectric driving section decreases. In order to maintain the resonance frequency, it is preferable to shorten the length of the first piezoelectric driving sections 112a and 112b along the first axis. However, when the length of the first piezoelectric driving sections 112a and 112b along the first axis is shortened, the amplitude of the tips of the first piezoelectric driving sections 112a and 112b decreases, so that the amount of amplitude of the tips of the first piezoelectric driving sections decreases, and it may be difficult to align the oscillation center with the center of the mirror section 101. In addition, if the amount of amplitude is increased while the length is shortened, the deformation per unit length of the piezoelectric driving section increases, and it becomes more likely to break.

[0103] Therefore, in this embodiment, the first driving thick parts 117a and 117b and the second driving thick parts 118a and 118 are respectively extended on the lower surfaces of the first piezoelectric driving parts 112a and 112b along the direction in which the deflection of the primary bending in the first piezoelectric driving parts 112a and 112b increases and decreases. With this configuration, the bending rigidity of the first piezoelectric driving parts 112a and 112b increases, so that the resonance frequency of the bending mode of the first piezoelectric driving parts 112a and 112b can be set close to the frequency of the torsion mode resonance of the torsion bars 111a and 111b while maintaining a sufficient length of the first piezoelectric driving parts 112a and 112b.

[0104] 14 is a bottom view illustrating the movable device 13c according to the present embodiment. As shown in FIG 14, the movable device 13c has first driving thick portions 117a and 117b and second driving thick portions 118a and 118b.

[0105] The first driving thick portions 117a and 117b and the second driving thick portions 118a and 118b are composed of a silicon support layer 161 formed on the underside of the silicon active layer 163 in the first piezoelectric driving portions 112a and 112b, and are thicker than the portions composed only of the silicon active layer 163 in the first piezoelectric driving portions 112a and 112b.

[0106] The first driving thick portions 117a and 117b and the second driving thick portions 118a and 118b each extend along a direction B perpendicular to the first axis. This direction B corresponds to the direction in which the deflection of the primary bending of the first piezoelectric driving portions 112a and 112b increases and decreases.

[0107] The first driving thick portion 117a is connected to the connecting thick portion 115a provided at the connecting portion 113a, extends from the connecting portion 113a to the fixed portion 121 along the B direction, and is connected to the fixed portion 121. The first driving thick portion 117b is connected to the connecting thick portion 115b provided at the connecting portion 113b, extends from the connecting portion 113b to the fixed portion 121 along the B direction, and is connected to the fixed portion 121.

[0108] The second driving thick portion 118a is provided on the mirror portion 101 side of the first driving thick portion 117a, extends along the B direction, and is connected to the fixed portion 121. The second driving thick portion 118b is provided on the mirror portion 101 side of the first driving thick portion 117b, extends along the B direction, and is connected to the fixed portion 121.

[0109] This configuration increases the bending rigidity of the first piezoelectric driving parts 112a and 112b, and while maintaining a sufficient length of the first piezoelectric driving parts 112a and 112b, the resonance frequency of the bending mode of the first piezoelectric driving parts 112a and 112b can be set close to the resonance frequency of the twisting mode of the torsion bars 111a and 111b. As a result, the oscillation center is made to substantially coincide with the center of the mirror part 101, and the surface deformation of the mirror part 101 can be reduced.

[0110] When the torsion bars 111a and 111b are provided with the supporting thick portions 114a and 114b, it is preferable that the first driving thick portion 117a is connected to the supporting thick portion 114a, and the first driving thick portion 117b is connected to the supporting thick portion 114b.

[0111] 15 is a bottom view illustrating a movable device 13d according to a modified example of this embodiment. The movable device 13d has a first driving thick portion 117da and a first driving thick portion 117db. The first driving thick portion 117da is connected to the supporting thick portion 114a, and the first driving thick portion 117db is connected to the supporting thick portion 114b. With this configuration, there is no portion where the thickness changes suddenly, so that stress concentration can be suppressed and the fracture limit angle can be increased.

[0112] Here, Fig. 16 is a diagram showing an example of the relationship between the offset ΔS, the length of the first piezoelectric driving parts 112a and 112b, and the position of the oscillation center. Fig. 16(a) shows a case where none of the driving thick parts 116a and 116b, the first driving thick parts 117a and 117b, and the second driving thick parts 118a and 118b are provided on the first piezoelectric driving parts 112a and 112b, and Fig. 16(b) shows this embodiment.

[0113] As shown in FIG. 16(a), when none of the driving thick portions 116a and 116b, the first driving thick portions 117a and 117b, and the second driving thick portions 118a and 118b are provided in the first piezoelectric driving portions 112a and 112b, even if the offset ΔS is increased, the oscillation center does not become zero, i.e., the center of the mirror portion 101 does not coincide with the oscillation center.

[0114] On the other hand, as shown in Fig. 16(b), in this embodiment, the combination of the offset ΔS and the first piezoelectric driving units 112a and 112b can cause the oscillation center to become zero. In Fig. 16, the point where the oscillation center becomes zero is the optimal design solution, and the mirror can be rotated appropriately. In addition, by doing so, the surface deformation of the mirror unit 101 can be minimized.

[0115] Here, Fig. 17 is a diagram showing an example of the relationship between the offset ΔS, the lengths of the first piezoelectric drive parts 112a and 112b, and the surface deformation. The vertical axis in Fig. 17 is a plot of the Peak to Peak [nm] of the surface deformation shown in Fig. 18. Fig. 18 is a diagram showing an example of the surface deformation of the mirror part 101.

[0116] <Effects of the movable device 13c> Next, the function and effect of the movable device 13c will be described.

[0117] Conventionally, the length of the piezoelectric driving section has been adjusted in order to set the first bending mode resonance frequency of the piezoelectric driving section close to the resonance frequency of the mirror section.

[0118] In this embodiment, the first driving thick parts 117a and 117b and the second driving thick parts 118a and 118b are respectively extended on the lower surfaces of the first piezoelectric driving parts 112a and 112b in the direction in which the deflection of the first bending of the first piezoelectric driving parts 112a and 112b increases and decreases. This makes it possible to freely adjust the first bending mode resonance frequency of the first piezoelectric driving parts 112a and 112b while keeping the length of the first piezoelectric driving parts 112a and 112b along the direction perpendicular to the first axis fixed.

[0119] Since the shorter the length of the first piezoelectric driving units 112a and 112b, the more compact the first support frame 120 can be, the shorter the length of the first piezoelectric driving units 112a and 112b is, the more preferable it is to increase the resonance frequency of the oscillation around the second axis. However, even if the length is made shorter than the diameter of the mirror unit 101, the first support frame 120 does not become small.

[0120] Furthermore, when the first piezoelectric driving units 112a and 112b are shortened, the area in which the piezoelectric unit 302 can be arranged becomes smaller, and the generated driving force decreases, so that the amplitude angle of the mirror also decreases. Furthermore, to make the oscillation center of the mirror unit 101 coincide with the center of the mirror unit 101, that is, to make the amplitude ΔZ in the Z direction of the center of the mirror unit 101 zero, the amplitude of the tips of the first piezoelectric driving units 112a and 112b according to the offset ΔS is required.

[0121] In addition, the shorter the first piezoelectric driving parts 112a and 112b are, the sharper the bend becomes, so that the stress applied to the first piezoelectric driving parts 112a and 112b increases, making them more likely to break. Therefore, it is preferable that the first piezoelectric driving parts 112a and 112b have a certain degree of length.

[0122] Furthermore, as the mirror portion 101 becomes larger, the load applied to the first piezoelectric driving portions 112a and 112b increases, so that when the bases of the first piezoelectric driving portions 112a and 112b reach their breaking limit, it is preferable to increase the width of the first piezoelectric driving portions 112a and 112b and increase the width at which they are fixed to the first support frame 120.

[0123] From the above viewpoints, it is preferable to set the length of the first piezoelectric actuators 112a and 112b so that the first piezoelectric actuators 112a and 112b on both sides are connected at the end of the mirror section 101 on the -Y direction side.

[0124] With the length of the first piezoelectric actuators 112a and 112b set in this way, the number and width of the thick driving parts can be adjusted to adjust the primary bending mode resonance frequency of the first piezoelectric actuators 112a and 112b. Then, the oscillation center and surface deformation of the mirror part 101 can be adjusted to optimally design the movable device 13c.

[0125] As a modification of the second embodiment, a configuration like a movable device 13e shown in Fig. 19 or a movable device 13f shown in Fig. 20 can be used. Here, Fig. 19 is a bottom view illustrating the movable device 13e, and Fig. 20 is a bottom view illustrating the movable device 13f.

[0126] As shown in Fig. 19, the movable device 13e has second driving thick portions 118ea and 118eb extending in a direction intersecting the first axis. The second driving thick portion 118ea is connected to the first driving thick portion 117a, and the second driving thick portion 118eb is connected to the first driving thick portion 117b. The rigidity of the first piezoelectric driving portions 112a and 112b can be adjusted by changing the distance D shown in Fig. 19, the width and angle of the first driving thick portions 117a and 117b, or the second driving thick portions 118ea and 118eb.

[0127] If the resonant frequency becomes too high, the resonant frequency may be lowered by providing a gap E between the support frame 120 as shown in FIG.

[0128] [Other Preferred Embodiments] The movable device 13 according to the embodiment described above can be applied to various systems and devices. Application examples of the movable device 13 to various systems and devices will be described below.

[0129] [Optical scanning system] First, an optical scanning system to which the movable device of this embodiment is applied will be described in detail with reference to Fig. 21 to Fig. 24. Fig. 21 shows a schematic diagram of an example of an optical scanning system. As shown in Fig. 21, an optical scanning system 10 is a system that optically scans a scanned surface 15 by deflecting light irradiated from a light source device 12 by a reflecting surface 14 of a movable device 13 under the control of a control device 11.

[0130] The optical scanning system 10 comprises a control device 11, a light source device 12, and a movable device 13 having a reflective surface 14.

[0131] The control device 11 is, for example, an electronic circuit unit including a CPU (Central Processing Unit) and an FPGA (Field-Programmable Gate Array), etc. The movable device 13 is, for example, a MEMS device having a reflective surface 14 that is movable.

[0132] The light source device 12 is, for example, a laser device that irradiates a laser. The scanned surface 15 is, for example, a screen.

[0133] The control device 11 generates control commands for the light source device 12 and the movable device 13 based on the acquired optical scanning information, and outputs drive signals to the light source device 12 and the movable device 13 based on the control commands. The light source device 12 performs light emission based on the input drive signal. The movable device 13 rotationally vibrates the reflection surface 14 in at least one of one axial direction or two axial directions based on the input drive signal.

[0134] Thereby, for example, by controlling the control device 11 based on image information, which is an example of optical scanning information, the reflection surface 14 of the movable device 13 is rotated and vibrated back and forth in two axial directions within a predetermined range, and as a result, the irradiation light from the light source device 12 incident on the reflection surface 14 is deflected around one axis to perform optical scanning, so that an arbitrary image can be projected onto the scanned surface 15. Details of the movable device of this embodiment and details of the control by the control device will be described later.

[0135] Next, a hardware configuration of an example of the optical scanning system 10 will be described with reference to Fig. 22. Fig. 22 is a hardware configuration diagram of an example of the optical scanning system 10. As shown in Fig. 22, the optical scanning system 10 includes a control device 11, a light source device 12, and a movable device 13, which are electrically connected to each other. Among these, the control device 11 includes a CPU 20, a RAM 21 (Random Access Memory), a ROM 22 (Read Only Memory), an FPGA 23, an external I / F 24, a light source device driver 25, and a movable device driver 26.

[0136] The CPU 20 is a calculation device that reads out programs and data from a storage device such as a ROM 22 onto a RAM 21 and executes processing to realize the overall control and functions of the control device 11.

[0137] The RAM 21 is a volatile storage device that temporarily stores programs and data.

[0138] The ROM 22 is a non-volatile storage device that can retain programs and data even when the power is turned off, and stores processing programs and data that the CPU 20 executes to control each function of the optical scanning system 10.

[0139] The FPGA 23 is a circuit that outputs control signals suitable for the light source device driver 25 and the movable device driver 26 in accordance with the processing of the CPU 20 .

[0140] The external I / F 24 is, for example, an interface with an external device, a network, etc. The external device includes, for example, a higher-level device such as a PC (Personal Computer), and a storage device such as a USB memory, an SD card, a CD, a DVD, a HDD, an SSD, etc. Furthermore, the network is, for example, a CAN (Controller Area Network) or a LAN (Local Area Network) of an automobile, the Internet, etc. The external I / F 24 may have a configuration that enables connection or communication with an external device, and an external I / F 24 may be provided for each external device.

[0141] The light source device driver 25 is an electric circuit that outputs a drive signal such as a drive voltage to the light source device 12 in accordance with an input control signal.

[0142] The movable device driver 26 is an electric circuit that outputs a drive signal, such as a drive voltage, to the movable device 13 in accordance with the input control signal.

[0143] In the control device 11, the CPU 20 acquires optical scanning information from an external device or a network via the external I / F 24. Note that any configuration may be used as long as the CPU 20 can acquire the optical scanning information, and the optical scanning information may be stored in the ROM 22 or FPGA 23 in the control device 11, or a storage device such as an SSD may be newly provided in the control device 11 to store the optical scanning information in the storage device.

[0144] Here, the optical scanning information is information indicating how to optically scan the scanned surface 15. For example, when an image is displayed by optical scanning, the optical scanning information is image data. For example, when optical writing is performed by optical scanning, the optical scanning information is writing data indicating the writing order and writing locations. For example, when object recognition is performed by optical scanning, the optical scanning information is irradiation data indicating the timing and irradiation range of irradiating light for object recognition.

[0145] The control device 11 can realize the following functional configuration by instructions from the CPU 20 and the hardware configuration shown in FIG.

[0146] Next, a functional configuration of the control device 11 of the optical scanning system 10 will be described with reference to Fig. 23. Fig. 23 is a functional block diagram of an example of the control device 11 of the optical scanning system.

[0147] As shown in FIG. 23, the control device 11 has a control section 30 and a drive signal output section 31 as functions.

[0148] The control unit 30 is realized by, for example, the CPU 20, the FPGA 23, etc., and acquires optical scanning information from an external device, converts the optical scanning information into a control signal, and outputs it to the drive signal output unit 31. For example, the control unit 30 acquires image data from an external device, etc. as optical scanning information, generates a control signal from the image data by performing a predetermined process, and outputs it to the drive signal output unit 31. The drive signal output unit 31 is realized by the light source device driver 25, the movable device driver 26, etc., and outputs a drive signal to the light source device 12 or the movable device 13 based on the input control signal.

[0149] The drive signal is a signal for controlling the drive of the light source device 12 or the movable device 13. For example, in the light source device 12, the drive signal is a drive voltage for controlling the timing and intensity of irradiation of the light source. Also, in the movable device 13, the drive signal is a drive voltage for controlling the timing and range of movement of the reflective surface 14 of the movable device 13.

[0150] Next, a process of optically scanning the surface 15 to be scanned by the optical scanning system 10 will be described with reference to Fig. 24. Fig. 24 is a flowchart of an example of a process related to the optical scanning system.

[0151] In step S11, the control unit 30 acquires optical scanning information from an external device or the like. In step S12, the control unit 30 generates a control signal from the acquired optical scanning information and outputs the control signal to the drive signal output unit 31. In step S13, the drive signal output unit 31 outputs a drive signal to the light source device 12 and the movable device 13 based on the input control signal. In step S14, the light source device 12 performs light irradiation based on the input drive signal. Also, the movable device 13 performs rotational vibration of the reflection surface 14 based on the input drive signal. By driving the light source device 12 and the movable device 13, light is deflected in an arbitrary direction and optical scanning is performed.

[0152] In the above-described optical scanning system 10, one control device 11 has devices and functions for controlling the light source device 12 and the movable device 13, but the control device for the light source device and the control device for the movable device may be provided separately.

[0153] In the optical scanning system 10, the function of the control unit 30 of the light source device 12 and the movable device 13 and the function of the drive signal output unit 31 are provided in one control device 11, but these functions may exist separately, for example, a drive signal output device having the drive signal output unit 31 may be provided separately from the control device 11 having the control unit 30. Note that, in the optical scanning system 10, the movable device 13 having the reflective surface 14 and the control device 11 may constitute an optical deflection system that performs optical deflection.

[0154] In this way, by applying the movable device 13 of the embodiment to an optical scanning system, it is possible to suppress the decrease in resonance frequency that occurs when the movable part is made larger, and it is possible to provide an optical scanning system capable of optical scanning with high precision.

[0155] [Image projection device] Next, an image projection device to which the movable device of this embodiment is applied will be described in detail with reference to FIGS.

[0156] Fig. 25 is a schematic diagram of an embodiment of an automobile 400 equipped with a head-up display device 500, which is an example of an image projection device. Fig. 26 is a schematic diagram of an example of the head-up display device 500. The automobile 400 is an example of a moving body.

[0157] The image projection device is a device that projects an image by optical scanning, and is, for example, a head-up display device.

[0158] 25, the head-up display device 500 is installed, for example, near the windshield (windshield 401, etc.) of an automobile 400. Projection light L emitted from the head-up display device 500 is reflected by the windshield 401 and directed toward an observer (driver 402) who is a user. This allows the driver 402 to visually recognize an image projected by the head-up display device 500 as a virtual image. Note that a combiner may be installed on the inner wall surface of the windshield, and the user may visually recognize a virtual image by the projection light reflected by the combiner.

[0159] As shown in FIG. 26, in the head-up display device 500, laser light is emitted from red, green, and blue laser light sources 501R, 501G, and 501B. The emitted laser light passes through an incidence optical system including collimator lenses 502, 503, and 504 provided for each laser light source, two dichroic mirrors 505 and 506, and a light amount adjustment unit 507, and is then deflected by a movable device 13 having a reflecting surface 14. The deflected laser light passes through a projection optical system including a free-form surface mirror 509, an intermediate screen 510, and a projection mirror 511, and is projected onto a screen. In the head-up display device 500, the laser light sources 501R, 501G, and 501B, the collimator lenses 502, 503, and 504, and the dichroic mirrors 505 and 506 are unitized as a light source unit 530 by an optical housing.

[0160] The head-up display device 500 projects an intermediate image displayed on an intermediate screen 510 onto a windshield 401 of an automobile 400, thereby allowing a driver 402 to visually recognize the intermediate image as a virtual image.

[0161] The laser beams of the respective colors emitted from the laser light sources 501R, 501G, and 501B are converted into substantially parallel beams by collimator lenses 502, 503, and 504, respectively, and are combined by two dichroic mirrors 505 and 506. The dichroic mirrors 505 and 506 are each an example of a combining unit. The combined laser beams are two-dimensionally scanned by a movable device 13 having a reflecting surface 14 after the light amount is adjusted by a light amount adjusting unit 507. The projection light L two-dimensionally scanned by the movable device 13 is reflected by a free-form surface mirror 509, whereby distortion is corrected, and then the projection light L is focused on an intermediate screen 510 to display an intermediate image. The intermediate screen 510 is composed of a microlens array in which microlenses are arranged two-dimensionally, and the projection light L incident on the intermediate screen 510 is magnified in units of the microlenses.

[0162] The movable device 13 reciprocates the reflective surface 14 in two axial directions, thereby two-dimensionally scanning the projection light L incident on the reflective surface 14. The drive control of this movable device 13 is performed in synchronization with the emission timing of the laser light sources 501R, 501G, and 501B.

[0163] The above describes the head-up display device 500 as an example of an image projection device, but the image projection device may be any device that projects an image by performing optical scanning with the movable device 13 having the reflective surface 14. For example, the present invention can be similarly applied to a projector that is placed on a desk or the like and projects an image onto a display screen, or a head-mounted display device that is mounted on a mounting member that is mounted on the observer's head or the like and projects an image onto a reflective / transmissive screen of the mounting member or projects an image using the observer's eye as a screen.

[0164] In addition, the image projection device may be mounted not only on a vehicle or a mounting member, but also on a moving body such as an aircraft, a ship, or a mobile robot, or on a non-moving body such as a work robot that operates a drive object such as a manipulator without moving from its location.

[0165] In this way, by applying the movable device 13 of the embodiment to an image projection device, it is possible to suppress the decrease in resonance frequency that occurs when the movable part is made larger, and it is possible to provide an image projection device capable of optical scanning with high precision.

[0166] [Optical writing device] Next, an optical writing device to which the movable device of this embodiment is applied will be described in detail with reference to FIGS.

[0167] Fig. 27 shows an example of an image forming apparatus incorporating an optical writing device 600. Fig. 28 is a schematic diagram of an example of the optical writing device.

[0168] 27, the optical writing device 600 is used as a component of an image forming apparatus such as a laser printer 650 having a printer function using laser light. In the image forming apparatus, the optical writing device 600 optically writes on a photosensitive drum, which is a scanned surface 15, by optically scanning the photosensitive drum with one or more laser beams.

[0169] As shown in FIG. 28, in an optical writing device 600, a laser beam from a light source device 12 such as a laser element passes through an imaging optical system 601 such as a collimator lens, and is then deflected in one or two axial directions by a movable device 13 having a reflecting surface 14. The laser beam deflected by the movable device 13 then passes through a scanning optical system 602 consisting of a first lens 602a, a second lens 602b, and a reflecting mirror portion 602c, and is irradiated onto a surface 15 to be scanned (e.g., a photosensitive drum or photosensitive paper), thereby performing optical writing. The scanning optical system 602 forms an image of the light beam in a spot shape on the surface 15 to be scanned. The light source device 12 and the movable device 13 having the reflecting surface 14 are driven under the control of the control device 11.

[0170] In this way, the optical writing device 600 can be used as a component of an image forming device having a printer function using laser light. In addition, by changing the scanning optical system to enable optical scanning not only in one axis direction but also in two axes directions, the optical writing device 600 can be used as a component of an image forming device such as a laser label device that deflects a laser light onto a thermal medium, optically scans the medium, and prints by heating the medium.

[0171] The movable device 13 having the reflecting surface 14 applied to the optical writing device consumes less power to drive than a rotating polygon mirror using a polygon mirror or the like, which is advantageous for saving power in the optical writing device. Also, the wind noise generated by the movable device 13 when vibrating is smaller than that of a rotating polygon mirror, which is advantageous for improving the quietness of the optical writing device. The optical writing device requires an overwhelmingly smaller installation space than a rotating polygon mirror, and the amount of heat generated by the movable device 13 is small, making it easy to reduce the size, which is advantageous for reducing the size of the image forming device.

[0172] In this way, by applying the movable device 13 of the embodiment to an optical writing device, it is possible to suppress the decrease in resonance frequency that occurs when the movable part is made larger, and it is possible to provide an optical writing device capable of optical scanning with high precision.

[0173] [Distance measuring device] Next, a distance measuring device to which the movable device of the present embodiment is applied will be described in detail with reference to FIGS.

[0174] Fig. 29 and Fig. 30 are schematic diagrams of an automobile in which a laser radar device, which is an example of a distance measuring device, is mounted in a lamp unit that mounts the automobile's headlights, and Fig. 31 is a schematic diagram of an example of a laser radar device.

[0175] A distance measuring device is a device that measures the distance to an object in a target direction, such as a laser radar device.

[0176] 29 and 30, a laser radar device 700 is mounted on, for example, an automobile 701, performs optical scanning in a target direction, and receives reflected light from an object 702 present in the target direction, thereby measuring the distance to the object 702. The automobile 701 is an example of a moving body.

[0177] As shown in FIG. 31, the laser light emitted from the light source device 12 passes through an incident optical system consisting of a collimator lens 703, which is an optical system that converts divergent light into approximately parallel light, and a plane mirror 704, and is scanned in one or two axial directions by a movable device 13 having a reflecting surface 14. Then, the laser light passes through a projection lens 705, which is a projection optical system, and is irradiated onto an object 702 in front of the device. The light source device 12 and the movable device 13 are controlled by the control device 11. The reflected light reflected by the object 702 is optically detected by a photodetector 709. That is, the reflected light passes through a condenser lens 706, which is an incident light detection and light receiving optical system, and is received by an image sensor 707, which outputs a detection signal to a signal processing device 708. The signal processing device 708 performs predetermined processing, such as binarization and noise processing, on the input detection signal, and outputs the result to a distance measurement circuit 710.

[0178] The distance measurement circuit 710 recognizes the presence or absence of the target object 702 based on the time difference between when the light source device 12 emits laser light and when the laser light is received by the photodetector 709, or the phase difference between each pixel of the image sensor 707 that receives the light, and further calculates distance information to the target object 702.

[0179] The movable device 13 having the reflective surface 14 is less likely to break than a polygonal mirror and is small, making it possible to provide a small, highly durable radar device. Such a laser radar device can be attached to, for example, a vehicle, an aircraft, a ship, a robot, etc., and can optically scan a specified area to determine the presence or absence of an obstacle and the distance to the obstacle.

[0180] The above distance measuring device has been described as an example of a laser radar device 700, but the distance measuring device may be any device that performs optical scanning by controlling a movable device 13 having a reflective surface 14 with a control device 11, and measures the distance to the target object 702 by receiving reflected light with a photodetector, and is not limited to the above-mentioned embodiment.

[0181] For example, the present invention can be similarly applied to biometric authentication that calculates object information such as shape from distance information obtained by optically scanning a hand or face, and recognizes the target object by referring to a record, security sensors that recognize intruding objects by optically scanning a target range, and components of 3D scanners that calculate and recognize object information such as shape from distance information obtained by optical scanning, and output it as 3D data.

[0182] In this way, by applying the movable device 13 of the embodiment to a distance measuring device, it is possible to suppress the decrease in resonance frequency that occurs when the movable part is made larger, and it is possible to provide a distance measuring device capable of optical scanning with high accuracy.

[0183] [Laser headlamp] Next, a laser headlamp 50 in which the movable device of the present embodiment is applied to an automobile headlight will be described with reference to Fig. 32. Fig. 32 is a schematic diagram for explaining an example of the configuration of the laser headlamp 50.

[0184] The laser headlamp 50 includes a control device 11, a light source device 12b, a movable device 13 having a reflective surface 14, a mirror 51, and a transparent plate 52.

[0185] Light source device 12b is a light source that emits blue laser light. The light emitted from light source device 12b is incident on movable device 13 and reflected by reflection surface 14. Movable device 13 moves the reflection surface in the XY directions based on a signal from control device 11, and performs two-dimensional scanning in the XY directions with the blue laser light from light source device 12b.

[0186] The scanning light from the movable device 13 is reflected by the mirror 51 and enters the transparent plate 52. The front or back surface of the transparent plate 52 is covered with a yellow phosphor. When the blue laser light from the mirror 51 passes through the yellow phosphor coating on the transparent plate 52, it changes to white within the legally defined color range for headlights. As a result, the front of the car is illuminated with white light from the transparent plate 52.

[0187] The scanning light from the movable device 13 is scattered in a predetermined manner when passing through the phosphor of the transparent plate 52. This reduces glare on the illumination target in front of the automobile.

[0188] When the movable device 13 is applied to a headlight of an automobile, the colors of the light source device 12b and the phosphor are not limited to blue and yellow, respectively. For example, the light source device 12b may be near ultraviolet light, and the transparent plate 52 may be covered with a uniform mixture of phosphors of blue, green, and red, which are the three primary colors of light. Even in this case, the light passing through the transparent plate 52 can be converted to white light, and the front of the automobile can be illuminated with white light.

[0189] In this way, by applying the movable device 13 of the embodiment to a laser headlamp, it is possible to suppress the decrease in resonance frequency that occurs when the movable part is made larger, and it is possible to provide a laser headlamp that is capable of optical scanning with high precision.

[0190] [Head-mounted display] Next, a head mounted display 60 to which the movable device of the present embodiment is applied will be described with reference to Figs. 33-34. Here, the head mounted display 60 is a head mounted display that can be mounted on a human head, and can be shaped like glasses, for example. The head mounted display will be abbreviated to HMD hereinafter.

[0191] Fig. 33 is a perspective view illustrating an example of the appearance of the HMD 60. In Fig. 33, the HMD 60 is composed of a front 60a and a temple 60b, which are provided approximately symmetrically on the left and right sides. The front 60a can be composed of, for example, a light guide plate 61, and the optical system, control device, etc. can be built into the temple 60b.

[0192] Fig. 34 is a diagram illustrating a portion of the configuration of the HMD 60. Note that, although Fig. 34 illustrates the configuration for the left eye, the HMD 60 has a similar configuration for the right eye.

[0193] The HMD 60 includes a control device 11 , a light source unit 530 , a light amount adjustment section 507 , a movable device 13 having a reflecting surface 14 , a light guide plate 61 , and a half mirror 62 .

[0194] As described above, the light source unit 530 is a unit formed by unitizing the laser light sources 501R, 501G, and 501B, the collimator lenses 502, 503, and 504, and the dichroic mirrors 505 and 506 using an optical housing. In the light source unit 530, the three color laser beams from the laser light sources 501R, 501G, and 501B are combined by the dichroic mirrors 505 and 506. The light source unit 530 emits a combined parallel light.

[0195] The light from the light source unit 530 is adjusted in amount by the light amount adjustment section 507 and then enters the movable device 13. The movable device 13 moves the reflection surface 14 in the XY directions based on a signal from the control device 11, and performs two-dimensional scanning with the light from the light source unit 530. The drive control of this movable device 13 is performed in synchronization with the emission timing of the laser light sources 501R, 501G, and 501B, and a color image is formed by the scanning light.

[0196] The scanning light from the movable device 13 is incident on a light guide plate 61. The light guide plate 61 reflects the scanning light on its inner wall surface and guides the light to a half mirror 62. The light guide plate 61 is made of a resin or the like that is transparent to the wavelength of the scanning light.

[0197] The half mirror 62 reflects the light from the light guide plate 61 to the rear side of the HMD 60 and emits it in the direction of the eyes of a wearer 63 of the HMD 60. The half mirror 62 has, for example, a free curved surface shape. An image formed by the scanning light is formed on the retina of the wearer 63 by reflection from the half mirror 62. Alternatively, an image is formed on the retina of the wearer 63 by reflection from the half mirror 62 and the lens effect of the crystalline lens in the eyeball. Furthermore, spatial distortion of the image is corrected by reflection from the half mirror 62. The wearer 63 can observe the image formed by the light scanned in the XY directions.

[0198] Since 62 is a half mirror, an image based on light from the outside world and an image based on the scanning light are superimposed and observed by the wearer 63. By providing a mirror instead of the half mirror 62, it is possible to eliminate light from the outside world and to configure so that only the image based on the scanning light can be observed.

[0199] In this way, by applying the movable device 13 of the embodiment to a head mounted display, it is possible to suppress the decrease in resonance frequency that occurs when the movable part is made larger, and it is possible to provide a head mounted display capable of optical scanning with high precision.

[0200] [Packaging] Next, packaging of the movable device of this embodiment will be described with reference to FIG.

[0201] FIG. 35 is a schematic diagram of an example of a packaged movable device.

[0202] 35, the movable device 13 is attached to an attachment member 802 disposed inside a packaging member 801, and a part of the packaging member is covered with a transparent member 803 and sealed, thereby being packaged. Furthermore, an inert gas such as nitrogen is sealed inside the package. This suppresses deterioration of the movable device 13 due to oxidation, and further improves durability against environmental changes such as temperature.

[0203] Although examples of embodiments of the present invention have been described above, the present invention is not limited to such specific embodiments, and various modifications and variations are possible within the scope of the gist of the present invention described in the claims.

[0204] In the above-described embodiment, a configuration in which a reflective surface is provided on the movable part is exemplified, but this is not limited to this. The movable part may be provided with other optical elements such as a diffraction grating, a photodiode, a heater (e.g., a heater using SiN), a light source (e.g., a surface-emitting laser), etc., or may be provided with both a reflective surface and other optical elements. [Explanation of symbols]

[0205] 10 Optical Scanning System 11 Control device 12, 12b Light source device 13 Mobile Devices 14 Reflective surface 15 Scanned surface 25 Light source driver 26 Mobile Device Driver 30 Control section 31 Drive signal output section 50 Laser Headlamp 51 Mirror 52 Transparent plate 60 Head-mounted display 60a Front 60b Temple 61 Light guide plate 62 Half Mirror 63 Wearer 101 Mirror part (an example of a moving part) 102 Mirror base 110a, 110b First drive unit 111a, 111b Torsion bar (an example of a support part) 112a, 112b First piezoelectric actuator (an example of an actuator beam) 113a, 113b Connection 114a, 114b Support thick wall part 115a, 115b Connection thick part 116a, 116b Thick drive section 117a, 117b First driving thick part 118a, 118b Second driving thick portion 120 First support frame (an example of a support frame) 121 Fixed part 130a, 130b Second drive unit 140 2nd Support Slot 150 Electrode connection part 160a, 160b Piezoelectric element for detection Wa1, Wa2 width [Prior art documents] [Patent documents]

[0206] [Patent Document 1] Patent No. 5292880

Claims

1. A movable part; a support part having one end connected to the movable part and elastically supporting the movable part; a drive beam connected to the other end of the support portion and configured to deform the support portion to swing the movable portion around a predetermined swing axis; a connection portion that connects the support portion and the actuation beam; a support frame that supports the drive beam via a fixed portion, The support portion is provided with a thin support portion and a thick support portion that is thicker than the thin support portion and has the same thickness as the support frame, the connection portion is provided with a connection thin portion and a connection thick portion that is thicker than the connection thin portion and has the same thickness as the support thick portion, 2. An optical deflector, wherein the supporting thick portion and the connecting thick portion are connected to each other.

2. The drive beam is provided with a drive thin portion and a drive thick portion that is thicker than the drive thin portion, 2. The optical deflector according to claim 1, wherein the driving thick portion and the connecting thick portion are connected to each other with the same thickness.

3. the movable portion is provided with a movable thin portion and a movable thick portion that is thicker than the movable thin portion, 3. The optical deflector according to claim 1, wherein the movable thick portion and the supporting thick portion are connected to each other with the same thickness.

4. An optical deflector as described in Claim 3, wherein a connection portion between the movable thick portion and the supporting thick portion includes an obtuse angle when viewed in a plane.

5. 5. The optical deflector according to claim 1, wherein the thick connecting portion extends in a direction toward the fixed portion.

6. 6. The optical deflector according to claim 5, wherein a width along the oscillation axis of a portion of the connection portion closer to the support portion is wider than a width along the oscillation axis of a portion of the connection portion farther from the support portion.

7. A movable part; a support part having one end connected to the movable part and supporting the movable part; a drive beam connected to the other end of the support portion and configured to deform the support portion to swing the movable portion around a predetermined swing axis; a connection portion that connects the support portion and the actuation beam; a support frame that supports the drive beam via a fixed portion, The connection portion is provided with a connection thick portion, the drive beam is provided with a drive thin portion, a first drive thick portion, and a second drive thick portion, each of which is thicker than the drive thin portion and has the same thickness as the support frame; 13. An optical deflector, comprising: said first driving thick portion and said second driving thick portion extending in a direction perpendicular to said oscillation axis.

8. An optical deflector according to any one of claims 1 to 7; A light source that emits light, An image projection device which projects light emitted from the light source by deflecting the light.

9. The light source is provided in plurality, The plurality of light sources emit light of different wavelengths, A combining unit that combines the plurality of light beams emitted from the plurality of light sources is further provided, 9. The image projection device according to claim 8, wherein the light combined in the combining section is deflected and projected.

10. A head-up display comprising the optical deflector according to claim 1 .

11. A laser headlamp comprising the optical deflector according to any one of claims 1 to 7.

12. A head mounted display comprising the optical deflector according to claim 1 .

13. An optical deflector according to any one of claims 1 to 7; A light source that emits light, A distance measuring device comprising: a light source that is deflected; a light source that is reflected by the light source; a light source that is reflected by the light source; and a distance to the object that is detected by the light source.

14. A moving object comprising at least one of the head-up display according to claim 10, the laser headlamp according to claim 11, and the distance measuring device according to claim 13.

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