Movable device

Abstract

The present invention provides a movable device in which the connection between the movable part and the drive unit is less likely to break, even when the range of rotation of the movable part is increased. [Solution] A movable device comprising a movable part 101, a drive unit 110a for driving the movable part, and a connecting part 120a for connecting the movable part and the drive unit, wherein the drive unit displaces the connection part 113a with the connecting part, thereby displacing the connection part 101a of the movable part with the connecting part, and thereby rotating the movable part around a pivot axis (first axis), wherein the connecting part includes a plurality of torsion deformation parts 121A, 121B, 122A, 122B that twist and deform around torsion axes O1, O2 extending in a direction substantially parallel to the pivot axis due to the displacement of the connection part in the drive unit, and connecting beam parts 123A, 123B that connect the plurality of torsion deformation parts to each other.

Description

Technical Field

[0001] The present invention relates to a movable device.

Background Art

[0002] Conventionally, there is known a movable device having a movable part, a driving part that drives the movable part, and a connecting part that connects the movable part and the driving part, wherein the driving part displaces a connection site with the connecting part, so that a connection site of the movable part with the connecting part is displaced, thereby rotating the movable part around a rotation axis.

[0003] For example, Patent Document 1 discloses a movable device having a mirror part (movable part), four driving parts each including a piezoelectric body that drives the mirror part, and four long torsion bars (connecting parts) that connect each of the four driving parts and the mirror part. In this movable device, two of the four driving parts are arranged so as to face each other with the mirror part interposed therebetween. When these driving parts are driven, a connection site of the driving part with the torsion bar is displaced, whereby one end of the torsion bar is lifted, and a connection site of the mirror part connected to the other end of the torsion bar is also lifted. By driving the two driving parts arranged to face each other so as to lift the respective connection sites of the mirror part in opposite directions, the mirror part rotates around a rotation axis orthogonal to a straight line connecting the respective connection sites.

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the conventional movable device has a problem that when trying to increase the rotation range of the movable part, the connecting part that connects the movable part and the driving part is likely to break.

Means for Solving the Problems

[0005] To solve the above-mentioned problems, the present invention provides a movable device comprising a movable part, a drive unit for driving the movable part, and a connecting part for connecting the movable part and the drive unit, wherein the drive unit displaces the connection part with the connecting part, thereby displacing the connection part of the movable part with the connecting part, and the movable part is rotated around a pivot axis, wherein the connecting part includes a plurality of torsion deformation parts that are torsionally deformed around a torsion axis extending in a direction substantially parallel to the pivot axis due to the displacement of the connection part in the drive unit, and a connecting beam part that connects the plurality of torsion deformation parts to each other. [Effects of the Invention]

[0006] According to the present invention, even if the range of rotation of the movable part is increased, it is possible to provide a movable device in which the connecting part between the movable part and the drive part is less likely to break. [Brief explanation of the drawing]

[0007] [Figure 1] A plan view showing an example of a movable device in an embodiment. [Figure 2] A cross-sectional view showing a cross-section along the second axis in Figure 1. [Figure 3] A plan view showing another example of a movable device in the embodiment. [Figure 4] A plan view showing the movable device in the comparative example. [Figure 5] A schematic plan view showing the configuration of the connection part of the movable device in the embodiment. [Figure 6] This diagram illustrates the connection point as viewed from a direction parallel to the first axis. [Figure 7] An explanatory diagram illustrating the width of the torsion deformation section and the width of the connecting beam section that constitute the connection. [Figure 8] A schematic plan view showing the configuration of the connection part of the movable device in modified example 1. [Figure 9] A schematic plan view showing the configuration of the connection part of the movable device in modified example 2. [Modes for carrying out the invention]

[0008] The embodiments for carrying out the invention will be described below with reference to the drawings. In each drawing, the same reference numerals are used for identical components, and redundant explanations may be omitted.

[0009] In the following description of the embodiments, rotation, oscillation, and movement are considered synonymous. In some figures, mutually orthogonal X-axis, Y-axis, and Z-axis directions are shown. The Z-axis direction follows the stacking direction of each layer in the piezoelectric drive unit, etc. The view from the Z-axis direction may be described as a "plan view." In addition, in some figures, parallel diagonal lines are drawn on parts that are not cross-sections.

[0010] The X-axis direction includes the direction indicated by the arrow and its reverse direction. Within the X-axis direction, the direction the arrow is pointing may be denoted as the +X direction, and the opposite direction of the +X direction as the -X direction. The Y-axis direction includes the direction indicated by the arrow and its reverse direction. Within the Y-axis direction, the direction the arrow is pointing may be denoted as the +Y direction, and the opposite direction of the +Y direction as the -Y direction. The Z-axis direction includes the direction indicated by the arrow and its reverse direction. Within the Z-axis direction, the direction the arrow is pointing may be denoted as the +Z direction, and the opposite direction of the +Z direction as the -Z direction. These directions do not restrict the orientation of the movable device 13, and the orientation of the movable device 13 is arbitrary. The movable device may also be called an "optical deflector".

[0011] An embodiment of the movable device according to the present invention will be described with reference to Figures 1 and 2. Figure 1 is a plan view illustrating the movable device 13 in this embodiment. Figure 2 is a cross-sectional view showing a cross-section along the second axis in Figure 1.

[0012] The movable device 13 according to this embodiment comprises a mirror section 101 as a movable part, four drive sections 110a to 110d, connecting sections 120a to 120d, a support frame 140, an electrode connecting section 150, and a control device 11. This movable device 13 is suitable for vector scanning and Lissajous scanning.

[0013] The mirror section 101 has a reflective surface 14 that reflects incident light. The mirror section 101 is an example of a movable part. The four drive units 110a to 110d drive the mirror section 101 to rotate around the first axis and the second axis, respectively. The connecting units 120a to 120d connect the mirror section 101 to the four drive units 110a to 110d, respectively. The support frame 140 supports the four drive units 110a to 110d. The electrode connecting unit 150 is electrically connected to the four drive units 110a to 110d and the control device 11.

[0014] The support frame 140 may be a rectangular frame in plan view. The rectangular frame has sides along the X-axis and Y-axis in plan view. The four drive units 110a to 110d are each arranged corresponding to the corners of the support frame 140. In the drive unit 110a, a piezoelectric drive unit 112a is formed on the drive unit base 111a. The piezoelectric drive unit 112a is formed to have a rectangular shape in plan view. The piezoelectric drive unit 112a deforms the drive unit 110a (drive unit base 111a) in accordance with the applied drive voltage.

[0015] Similarly, the drive unit 110b has a piezoelectric drive unit 112b formed on the drive unit base 111b. Similarly, the drive unit 110c has a piezoelectric drive unit 112c formed on the drive unit base 111c. Similarly, the drive unit 110d has a piezoelectric drive unit 112d formed on the drive unit base 111d.

[0016] In this embodiment, among the four drive units 110a to 110d, two drive units 110a and 110c located diagonally opposite to each other function as a first drive unit that rotates (swings) the mirror unit 101 around a first axis. On the other hand, among the four drive units 110a to 110d, two drive units 110b and 110d located diagonally opposite to each other function as a second drive unit that rotates (swings) the mirror unit 101 around a second axis. Since the first axis and the second axis are in a relationship where their axial directions are orthogonal to each other, the movable device 13 of this embodiment can deflect light two-dimensionally by the reflecting surface 14 of the mirror unit 101. Such a movable device 13 is suitable for vector scanning, Lissajous scanning, and spiral scanning.

[0017] Note that the driving method of the drive units 110a to 110d is not limited to piezoelectric driving. The driving method of the drive units 110a to 110d may be electrostatic driving, electromagnetic driving, or thermoelectric driving.

[0018] The movable device 13 is formed, for example, by etching a single SOI (Silicon On Insulator) substrate and forming the reflecting surface 14, piezoelectric drive units 112a to 11 , and electrode connection parts 150 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 the SOI substrate is formed, or may be performed during the formation of the SOI substrate.

[0019] As shown in FIG. 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 (+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 referred to as a BOX (Buried Oxide) layer.

[0020] A member composed only of the silicon active layer 163 functions as an elastic part having elasticity.

[0021] The SOI substrate does not necessarily have to be planar; it may have curvature or other properties. The components used to form the movable device 13 can be integrally molded by etching or the like, and may be partially elastic substrates; they are not limited to SOI substrates.

[0022] The mirror portion 101 includes, for example, a circular mirror portion base 102 and a reflective surface 14 formed on the +Z side surface of the mirror portion base. The mirror portion base 102 includes, for example, a silicon active layer 163. The reflective surface 14 includes, for example, a thin metal film containing aluminum, gold, silver, etc.

[0023] A movable thickened portion for reinforcing the mirror portion may be formed on the -Z side surface of the mirror base 102. In that case, the movable thickened portion may include, for example, a silicon support layer 161 and a silicon oxide layer 162, and can suppress distortion of the reflective surface 14 caused by movement.

[0024] As shown in Figure 2, the four drive units 110a to 110d are formed by stacking a lower electrode 301, a piezoelectric part 302, and an upper electrode 303 in that order on the +Z side surface of the drive unit substrate 111a to 111d, which consists of a silicon active layer 163 that is an elastic part, thereby forming piezoelectric drive units 112a to 112d. The upper electrode 303 and 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.

[0025] As shown in Figure 2, the support frame 140 includes a silicon support layer 161, a silicon oxide layer 162, and a silicon active layer 163. The support frame 140 is a rectangular support that surrounds the mirror portion 101, the drive portions 110a to 110d, and the connecting portions 120a to 120d.

[0026] The electrode connection section 150 is formed on the +Z side surface of the support frame 140 and is electrically connected to the upper electrodes 303 and lower electrodes 301 of the four drive units 110a to 110d, and to the control device 11 via electrode wiring made of aluminum (Al) or the like. A signal voltage is applied to the lower electrode 301, and the upper electrode 303 is connected to ground (GND). The upper electrode 303 or the lower electrode 301 may be directly connected to the electrode connection section 150, or they may be indirectly connected by connecting the electrodes to each other.

[0027] In this embodiment, the case in which the piezoelectric drive units 112a to 112d are formed only on one surface (the +Z side) of the silicon active layer 163 forming the drive unit substrate 111a to 111d has been described as an example, but they may also be provided on the other surface (the -Z side) or on both sides.

[0028] Furthermore, an insulating layer made of silicon oxide film may be formed on at least one of the +Z-side surfaces of the upper electrodes 303 of the drive units 110a to 110d or on the +Z-side surface of the support frame 140. In this case, it becomes possible to provide electrode wiring on the insulating layer, thereby increasing the design flexibility of the drive units 110a to 110d and the electrode wiring, and suppressing short circuits caused by contact between electrodes. In addition, the silicon oxide film also functions as an anti-reflective material.

[0029] The control device 11 has the function of a control unit that applies drive voltages to the four drive units 110a to 110d in the movable device 13. When a positive or negative voltage is applied in the polarization direction to the piezoelectric parts 302 of the drive units 110a to 110d, deformation (e.g., expansion and contraction) proportional to the potential of the applied voltage occurs, exhibiting a so-called inverse piezoelectric effect. The drive units 110a to 110d rotate the mirror unit 101 around the first axis and the second axis using the inverse piezoelectric effect. In this case, the angle formed by the XY plane and the reflective surface 14 when the reflective surface 14 of the mirror unit 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 defined as the positive deflection angle, and the -Z direction as the negative deflection angle.

[0030] In each drive unit 110a to 110d, when a drive voltage, which is a drive signal, is applied to the piezoelectric part 302 of each piezoelectric drive unit 112a to 112d via the upper electrode 303 and the lower electrode 301, each piezoelectric part 302 deforms. Due to the action of this deformation of the piezoelectric part 302, the piezoelectric drive units 112a to 112d are bent. This displaces the connection points (the free ends opposite to the ends supported by the support frame 140 of each drive unit 110a to 110d) with each connection part 120a to 120d, thereby lifting (displacing in the +Z direction) or pushing down (displacing in the -Z direction) each connection part 120a to 120d. As a result, the connection points of the mirror unit 101 with each connection part 120a to 120d are displaced and lifted (displacing in the +Z direction) or pushed down (displacing in the -Z direction).

[0031] The control device 11 applies, for example, predetermined sinusoidal waveform drive voltages, which are in opposite phase to each other, to the piezoelectric drive units 112a and 112c of the pair of drive units 110a and 110c, which function as first drive units that rotate (oscillate) around the first axis. As a result, for example, when a positive drive voltage is applied to the drive unit 110a, a negative drive voltage is applied to the drive unit 110c. During this time, the connection points between each drive unit 110a and each connection point 120a and 120c are lifted (displaced in the +Z direction) on one side and pushed down (displaced in the -Z direction) on the other side. Consequently, the connection points of the mirror unit 101 with the respective connection points 120a and 120c are lifted (displaced in the +Z direction) on one side and pushed down (displaced in the -Z direction) on the other side. Therefore, the mirror portion 101 rotates in one rotational direction around a first axis that extends in a direction perpendicular to the imaginary line (second axis in this embodiment) passing through the connection points of the mirror portion 101 with the respective connection portions 120a and 120c.

[0032] Furthermore, following this, for example, when a negative drive voltage is applied to the drive unit 110a, a positive drive voltage is applied to the drive unit 110c. During this time, the connection points between each drive unit 110a and 110c and the respective connection points 120a and 120c are pushed down on one side (displaced in the -Z direction) and lifted up on the other side (displaced in the +Z direction). As a result, the connection points of the mirror unit 101 to the respective connection points 120a and 120c are pushed down on one side (displaced in the -Z direction) and lifted up on the other side (displaced in the +Z direction). Therefore, the mirror unit 101 rotates in the other rotational direction around the first axis which extends in a direction perpendicular to the imaginary line (second axis in this embodiment) passing through the connection points of the mirror unit 101 to the respective connection points 120a and 120c.

[0033] In this way, by applying predetermined sinusoidal waveform drive voltages that are out of phase to each other in parallel to the pair of drive units 110a and 110c, the mirror unit 101 oscillates at the period of the drive voltage so as to repeatedly rotate in one direction and then in the other direction around the first axis. For example, if the frequency of the drive voltage is set to approximately 20 kHz, which is about the same as the resonant frequency, the mirror unit 101 can be made to resonate and vibrate at approximately 20 kHz by utilizing the mechanical resonance that occurs.

[0034] Furthermore, the control device 11 also applies, for example, predetermined sinusoidal waveform drive voltages that are in opposite phase to each of the piezoelectric drive units 112b and 112d of the pair of drive units 110b and 110d, which function as a second drive unit that rotates (oscillates) around the second axis, in parallel. Therefore, similar to the case of the pair of drive units 110a and 110c described above that function as the first drive unit, the mirror unit 101 oscillates at the period of the drive voltage so as to repeatedly rotate in one rotation direction and then in the other rotation direction around the second axis.

[0035] As shown in Figure 1, the movable device 13 according to this embodiment has four drive units 110a to 110d arranged to correspond to each corner of the rectangular support frame 140, with the first axis extending in a direction of -45° with respect to the X direction, and the first axis extending in a direction of -45° with respect to the X direction, but is not limited to this configuration. For example, as shown in Figure 3, the movable device 13 may have four drive units 110a to 110d arranged to correspond to each side of the rectangular support frame 140, with the second axis extending in a direction of 0° with respect to the X direction and the first axis extending in a direction of 90° with respect to the X direction.

[0036] Next, the configuration of the connection parts 120a to 120d of the movable device 13 in this embodiment will be described. Since the configurations of the four connection sections 120a to 120d are essentially the same, the following explanation will focus on connection section 120a, omitting the explanations for the remaining connection sections 120b to 120d. Furthermore, for the sake of simplicity, the following explanation will use the configuration shown in Figure 3, where the second axis is parallel to the X direction and the first axis is parallel to the Y direction, rather than the example shown in Figure 1.

[0037] In this embodiment, the movable device 13 rotates the mirror portion 101 around the first axis by displacing the connection portion 113a between the drive unit 110a and the connection portion 120a, thereby displacing the connection portion 101a between the mirror portion 101 and the connection portion 120a. In such a movable device 13, for example, as shown in the comparative example in Figure 4, it is conceivable to adopt a configuration in which the drive unit 110a and the mirror portion 101 are connected by a connection portion 120a' consisting of a single long elastic member (for example, a beam member formed from the silicon active layer 163 of the SOI substrate).

[0038] However, in the comparative example shown in Figure 4, when the drive unit 110a is driven, bending deformation occurs in the connecting part 120a', which has a curvature center axis parallel to the first axis of the mirror part 101. In this comparative example, in order to increase the swing angle (rotation range) of the mirror part 101, it is necessary to increase the rigidity of the connecting part 120a' against bending deformation (bending rigidity). However, if the bending rigidity of the connecting part 120a' is increased, the stress due to the bending deformation of the connecting part 120a' increases, and the connecting part 120a' becomes more prone to breaking at the point where that stress is concentrated.

[0039] Furthermore, if the bending rigidity of the connection part 120a' is reduced, the stress due to the bending deformation of the connection part 120a' will be reduced, and that stress will be distributed, making the connection part 120a' less likely to break. However, when the drive unit 110a is driven, even if the connection part 113a of the drive unit 110a with the connection part 120a' is lifted or pushed down (displaced), the connection part 120a' bends significantly, making it impossible to sufficiently increase the amount (amount of displacement) that lifts or pushes down the connection part 101a of the mirror part 101 with the connection part 120a', and thus the swing angle (rotation range) of the mirror part 101 cannot be increased.

[0040] On the other hand, instead of rotating the mirror portion 101 around the first axis by bending deformation of the connection portion by the drive unit 110a, a configuration is also conceivable in which the mirror portion 101 is rotated around the first axis parallel to the torsional axis of the connection portion by torsional deformation of the connection portion by the drive unit 110a. With such a configuration, bending deformation of the connection portion having a curvature center axis parallel to the first axis can be suppressed, while the mirror portion 101 can be rotated around the first axis by torsional deformation of the connection portion, thereby preventing the connection portion from breaking due to bending deformation.

[0041] However, in this configuration, increasing the swing angle (rotation range) of the mirror section 101 requires increasing the torsional deformation of the connection point. Therefore, when the mirror section 101 is rotated by a single torsional axis, increasing the swing angle of the mirror section 101 increases the amount of torsional deformation around the torsional axis, resulting in excessive stress due to torsional deformation, which makes the connection point prone to breaking.

[0042] Figure 5 is a schematic plan view showing the configuration of the connection portion 120a of the movable device 13 in this embodiment. In this embodiment, the connecting portion 120a includes two torsion deformation portions 121A, 121B, 122A, and 122B that are torsionally deformed around a plurality of torsion axes O1 and O2 extending in a direction substantially parallel to the first axis due to the displacement of the connecting portion 113a in the drive portion 110a, and connecting beam portions 123A and 123B that connect these torsion deformation portions to each other.

[0043] The connection portion 120a of this embodiment has a symmetrical structure with respect to a virtual line (here, the second axis) passing through the connection portion 101a of the mirror portion 101. That is, one structural portion consisting of the structural part above the second axis in Figure 5 and the other structural portion consisting of the structural part below the second axis in Figure 5 have a symmetrical structure with respect to the second axis.

[0044] Specifically, one structural part (the structural part above the second axis in Figure 5) includes a first torsional deformation part 121A that deforms torsion around the first torsional axis O1, a second torsional deformation part 122A that deforms torsion around the second torsional axis O2, and an intermediate connecting beam part 123A that connects these torsional deformation parts 121A and 122A to each other.

[0045] Of these torsional deformation sections 121A and 122A, the first torsional deformation section 121A, located on the mirror section 101 side along the displacement transmission path, has its end opposite to the end connected to the intermediate connecting beam section 123A connected to one end of the mirror section side connecting beam section 124. As a result, the end of the first torsional deformation section 121A opposite to the end connected to the intermediate connecting beam section 123A is connected to the connection portion 101a of the mirror section 101 via the mirror section side connecting beam section 124.

[0046] Furthermore, of these torsional deformation sections 121A and 122A, the second torsional deformation section 122A, located on the drive section 110a side along the displacement transmission path, has its end opposite to the end connected to the intermediate connecting beam section 123A connected to one end of the drive section side connecting beam section 125A. As a result, the end of the second torsional deformation section 122A opposite to the end connected to the intermediate connecting beam section 123A is connected to the connection portion 113a of the drive section 110a via the drive section side connecting beam section 125A.

[0047] The other structural part (the structural part below the second axis in Figure 5) is similar, and includes a first torsional deformation part 121B that deforms torsion around the first torsional axis O1, a second torsional deformation part 122B that deforms torsion around the second torsional axis O2, and an intermediate connecting beam part 123B that connects these torsional deformation parts 121B and 122B to each other.

[0048] Of these torsional deformation sections 121B and 122B, the first torsional deformation section 121B, located on the mirror section 101 side along the displacement transmission path, has its end opposite to the end connected to the intermediate connecting beam section 123B connected to one end of the mirror section side connecting beam section 124. As a result, the end of the first torsional deformation section 121B opposite to the end connected to the intermediate connecting beam section 123B is connected to the connection portion 101a of the mirror section 101 via the mirror section side connecting beam section 124.

[0049] Furthermore, of these torsional deformation sections 121B and 122B, the second torsional deformation section 122B, located on the drive section 110a side along the displacement transmission path, has its end opposite to the end connected to the intermediate connecting beam section 123B connected to one end of the drive section side connecting beam section 125B. As a result, the end of the second torsional deformation section 122B opposite to the end connected to the intermediate connecting beam section 123B is connected to the connection portion 113a of the drive section 110a via the drive section side connecting beam section 125B.

[0050] Figure 6 is an explanatory diagram showing the connection portion 120a of the movable device 13 of this embodiment as viewed from a direction parallel to the first axis. In the movable device 13 of this embodiment, as shown in Figure 6, when the drive unit 110a is driven, the connection portion 113a of the drive unit 110a is lifted and displaced, causing the connection portion 101a of the mirror unit 101 to also lift and displace, and the mirror unit 101 to rotate around the first axis.

[0051] Here, each connecting beam section 123A, 123B, 124, 125A, 125B in the connection section 120a is formed to have a bending rigidity higher than the torsional rigidity of the first torsional deformation section 121A, 121B and the second torsional deformation section 122A, 122B. Therefore, in the connection section 120a of this embodiment, when the drive section 110a is driven, torsional deformation occurs in the first torsional deformation section 121A, 121B and the second torsional deformation section 122A, 122B, but little to no bending deformation occurs in each connecting beam section 123A, 123B, 124, 125A, 125B. As a result, the displacement loss due to bending deformation of the connecting beam sections 123A, 123B, 124, 125A, and 125B (the loss of displacement at the connection point 101a of the mirror section 101 relative to the displacement at the connection point 113a of the drive section 110a) can be suppressed.

[0052] On the other hand, in this embodiment, as shown in Figure 6, when the drive unit 110a is driven, the first torsional deformation parts 121A and 121B undergo torsional deformation of an angle θ1 around the first torsional axis O1, and the second torsional deformation parts 122A and 122B undergo torsional deformation of an angle θ2 around the second torsional axis O2. As a result, the mirror part 101 can be made to rotate around the first axis with a swing angle of θ1 + θ2, as shown in Figure 6.

[0053] In other words, in this embodiment, when the mirror portion 101 is rotated around the first axis with a swing angle of θ1 + θ2, the amount of torsional deformation (torsion angle) generated in the connection portion 120a can be distributed between the torsion angle θ1 of the first torsional deformation portions 121A and 121B and the torsion angle θ2 of the second torsional deformation portions 122A and 122B. As a result, the individual amounts of torsional deformation generated in the connection portion 120a (each torsion angle θ1, θ2 in each torsional deformation portion) become smaller than the swing angle θ1 + θ2 of the mirror portion 101. Therefore, according to this embodiment, the stress due to torsional deformation generated in the connection portion 120a can be kept to a minimum, and the connection portion 120a can be made less prone to breakage.

[0054] Furthermore, in the connection portion 120a of this embodiment, it is required to obtain a characteristic in which the torsional rigidity of the torsion deformation portions 121A, 121B, 122A, and 122B is lower than the bending rigidity of each connecting beam portion 123A, 123B, 124, 125A, and 125B. In this case, it is possible to obtain the above characteristic by forming each connecting beam portion 123A, 123B, 124, 125A, and 125B and the torsion deformation portions 121A, 121B, 122A, and 122B from different materials. However, when the entire structure is manufactured from a hard material such as silicon (Si), as in the movable device 13 of this embodiment which uses micromachining technology, it is extremely difficult to manufacture only a part of the connection portion 120a (the torsion deformation portions 121A, 121B, 122A, and 122B) from a soft material.

[0055] Therefore, in the connection section 120a of this embodiment, as shown in Figure 7, the displacement transmission path widths Lt1 and Lt2 of the torsional deformation sections 121A, 121B, 122A, and 122B are configured to be shorter than the displacement transmission path widths Ls1, Ls2, and Ls3 of the connecting beam sections 123A, 123B, 124, 125A, and 125B. More specifically, in the connection section 120a of this embodiment, the displacement transmission path widths Lt1 and Lt2 of the torsional deformation sections 121A, 121B, 122A, and 122B are configured to be as narrow as possible.

[0056] The width referred to here means the width of the route (displacement transmission path) through which the displacement of the connection portion 113a of the drive unit 110a travels when the drive unit 110a is driven, via the drive unit side connecting beam portions 125A, 125B, the second torsional deformation portions 122A, 122B, the intermediate connecting beam portions 123A, 123B, the first torsional deformation portions 121A, 121B, and the mirror portion side connecting beam portion 124 of the connection portion 120a, to displace the connection portion 101a of the mirror portion 101a.

[0057] Therefore, the width Lt1 of the first torsion deformation sections 121A and 121B and the width Lt2 of the second torsion deformation sections 122A and 122B represent the lengths in a direction perpendicular to the respective torsion axes O1 and O2 and parallel to the substrate surface of the SOI substrate. In addition, the width Ls1 of the intermediate connecting beam sections 123A and 123B, the width Ls2 of the mirror section-side connecting beam section 124, and the width Ls3 of the drive section-side connecting beam sections 125A and 125B represent the lengths in a direction perpendicular to the respective longitudinal direction and parallel to the substrate surface of the SOI substrate.

[0058] With this configuration, even if each connecting beam section 123A, 123B, 124, 125A, 125B and the first torsional deformation sections 121A, 121B and the second torsional deformation sections 122A, 122B are formed from the same substrate and have the same thickness, it is possible to obtain a characteristic in which the torsional rigidity of the torsional deformation sections 121A, 121B, 122A, 122B is lower than the bending rigidity of each connecting beam section 123A, 123B, 124, 125A, 125B.

[0059] When the movable device 13 of this embodiment is manufactured integrally using a semiconductor process with an SOI substrate, the main material forming the connection portion 120a is silicon (silicon active layer 163). Therefore, both the torsion deformation portions 121A, 121B, 122A, 122B and the connecting beam portions 123A, 123B, 124, 125A, 125B are formed of silicon (Si). In this case, for example, the widths Lt1, Lt2 of the torsion deformation portions 121A, 121B, 122A, 122B are preferably about 10±5 [μm], and the widths Ls1, Ls2, Ls3 of the connecting beam portions 123A, 123B, 124, 125A, 125B are preferably about 50±20 [μm]. In terms of the ratio of the width Lt of the torsion deformation section to the width Ls of the connecting beam section, it is preferable to manufacture the structure such that the relationship 0.071 ≤ Lt / Ls ≤ 0.5 is satisfied.

[0060] Furthermore, in this embodiment, the connecting portion 120a has a folded structure in which the intermediate connecting beam portions 123A and 123B, which are connected to the drive unit side connecting beam portions 125A and 125B via the second torsional deformation portions 122A and 122B, are located on the same side as the drive unit side connecting beam portions 125A and 125B with respect to the torsional axis O2 of the second torsional deformation portions 122A and 122B. This makes it possible to shorten the longitudinal length (X-direction length in this example) of the connecting beam portion in the movable device 13 compared to a structure in which the intermediate connecting beam portions 123A and 123B are located on the opposite side from the drive unit side connecting beam portions 125A and 125B with respect to the torsional axis O2 of the second torsional deformation portions 122A and 122B.

[0061] Similarly, in this embodiment, the connecting section 120a has a folded structure in which the intermediate connecting beam sections 123A and 123B, which are connected to the mirror section-side connecting beam section 124 via the first torsional deformation sections 121A and 121B, are located on the same side as the mirror section-side connecting beam section 124 with respect to the torsional axis O1 of the first torsional deformation sections 121A and 121B. This makes it possible to shorten the longitudinal length (X-direction length in this example) of the connecting beam section in the movable device 13 compared to a structure in which the intermediate connecting beam sections 123A and 123B are located on the opposite side of the mirror section-side connecting beam section 124 with respect to the torsional axis O1 of the first torsional deformation sections 121A and 121B.

[0062] [Variation 1] Next, a modified example of the movable device 13 in the above-described embodiment (hereinafter referred to as "Modified Example 1") will be explained. In the above-described embodiment, the movable device 13 has two pivot axes on which the mirror portion 101 rotates, and the first and second axes are perpendicular to each other. Therefore, for example, in the connecting portion 120a, when the mirror portion 101 rotates around the second axis due to the driving of the drive units 110b and 110d, twisting occurs around the second axis.

[0063] At this time, since the torsional axes of the torsional deformation parts 121A, 121B, 122A, and 122B of the connection part 120a are parallel to the second axis, the twist around the second axis that occurs in the connection part 120a cannot be supported by the torsional deformation in the torsional deformation parts, and the resistance force of the connection part 120a against the twist around the second axis is large. This resistance force of the connection part 120a hinders the rotation of the mirror part 101 around the second axis by the drive of the drive parts 110b and 110d, thereby narrowing the swing angle (rotation range) of the mirror part 101 around the second axis. This also applies to the remaining connection sections 120b to 120d.

[0064] Figure 8 is a schematic plan view showing the configuration of the connection portion 120a of the movable device 13 in this modified example 1. In this modified example 1, the configuration of the four connection parts 120a to 120d is substantially the same; therefore, in the following explanation, only connection part 120a will be described, and the explanation of the remaining connection parts 120b to 120d will be omitted.

[0065] The basic configuration of the connection portion 120a in this modified example 1 is the same as that of the embodiment described above, but the connection portion 120a in this modified example 1 is further enhanced by the addition of third torsional deformation portions 126A and 126B, which are other torsional deformation portions that deform torsion around a torsion axis O3 extending in a direction substantially parallel to the second axis. In this modified example 1, the third torsional deformation portions 126A and 126B are positioned between the drive unit side connecting beam portions 125A and 125B and the second torsional deformation portions 122A and 122B. That is, one end of the third torsional deformation portions 126A and 126B is connected to the end of the drive unit side connecting beam portions 125A and 125B, and the other end of the third torsional deformation portions 126A and 126B is connected to the end of the second torsional deformation portions 122A and 122B.

[0066] The third torsional deformation sections 126A and 126B are formed to have low rigidity against torsional deformation around the torsion axis O3, similar to, for example, the first torsional deformation sections 121A and 121B and the second torsional deformation sections 122A and 122B. Specifically, the width Lt3 of the third torsional deformation sections 126A and 126B is configured to be shorter than the widths Ls1, Ls2, and Ls3 of the connecting beam sections 123A, 123B, 124, 125A, and 125B.

[0067] In this modified example 1, when the mirror section 101 rotates around the second axis due to the drive of the drive units 110b and 110d, the twist around the second axis generated in the connecting section 120a can be absorbed by the torsional deformation of the third torsional deformation sections 126A and 126B, which have a torsional axis O3 substantially parallel to the second axis. Since the torsional rigidity of the third torsional deformation sections 126A and 126B is low, the resistance force of the connecting section 120a against the twist around the second axis can be kept small. Therefore, according to this modified example 1, the rotation of the mirror section 101 around the second axis due to the drive of the drive units 110b and 110d is less likely to be hindered by the resistance force of the connecting section 120a, and the situation in which the swing angle (rotation range) of the mirror section 101 around the second axis is narrowed is suppressed.

[0068] In this modified example 1, the remaining connection parts 120b to 120d also have the same configuration as the connection part 120a described above. Therefore, the rotation of the mirror part 101 around the first axis driven by the drive parts 110a and 110c, and the rotation of the mirror part 101 around the second axis driven by the drive parts 110b and 110d, are not easily hindered by the resistance of the connection parts 120a to 120d. Thus, with the movable device 13 of this modified example 1, the mirror part 101 can be rotated in a two-dimensional direction with a large swing angle (rotation range).

[0069] [Variation 2] Next, another modification of the movable device 13 in the above-described embodiment (hereinafter referred to as "modification 2") will be explained. In the movable device 13 of the embodiment described above, the connecting portion 120a has a symmetrical structure with respect to a virtual line (second axis) passing through the connecting portion 101a of the mirror portion 101, and the remaining connecting portions 120b to 120d have a similar structure, but are not limited to this. This modified example 2 is an example in which the connecting portions 120a to 120d have an asymmetrical structure.

[0070] Figure 9 is a schematic plan view showing the configuration of the connection portion 120a of the movable device 13 in this modified example 2. In this modified example 2, the configuration of the four connection parts 120a to 120d is substantially the same; therefore, in the following explanation, only connection part 120a will be described, and the explanation of the remaining connection parts 120b to 120d will be omitted.

[0071] This modified example 2 shows an example of an asymmetrical structure of the connecting portion 120a, in which the structure is asymmetrical with respect to a virtual line (second axis) passing through the connecting portion 101a of the mirror portion 101. Specifically, compared to the connecting portion 120a with a symmetrical structure shown in Figure 5, one structural part consisting of the structural part above the second axis in Figure 5 is eliminated, and the connecting portion 120a is composed only of the other structural part consisting of the structural part below the second axis in Figure 5. Even with an asymmetrical structure of the connecting portion 120a as in this modified example 2, the same effects as the embodiment described above can be achieved.

[0072] In the embodiments described above (including modifications), the detailed shape of each component is not limited to the shape of the embodiment. Furthermore, the materials, manufacturing processes, electrical connections, and control methods are not limited to the examples of the embodiment. For example, in the embodiments described above, the movable part is an example of an optical deflector in which the mirror part 101 is used, but the movable part may have a diffraction grating, a photodiode, a light-receiving element, a heater (e.g., a heater using SiN), a light source (e.g., a surface-emitting laser), etc. instead of the mirror part.

[0073] Furthermore, when the movable device 13 of the above-described embodiment (including modified versions) is used as an optical deflector, it can also be applied to optical scanning systems equipped with the movable device 13, projection devices, mobile bodies such as automobiles equipped with the projection device, head-mounted displays, head-up displays, laser headlamps, object recognition devices, pupil or corneal position detection devices, and the like.

[0074] The above is just one example; each of the following embodiments produces its own unique effects. [First aspect] The first embodiment is a movable device 13 having a movable part (for example, a mirror part 101), drive units 110a to 110d for driving the movable part, and connecting parts 120a to 120d for connecting the movable part and the drive units, wherein the drive units displace the connection parts 113a to 113d with the connecting parts, thereby displacing the connection parts 101a to 101d of the movable part with the connecting parts, and thereby rotating the movable part around a pivot axis (for example, a first axis and a second axis), wherein the connecting parts include a plurality of torsion deformation parts 121A, 121B, 122A, 122B that twist and deform around torsion axes O1, O2 extending in a direction substantially parallel to the pivot axis due to the displacement of the connection parts in the drive units, and connecting beam parts (for example, intermediate connecting beam parts 123A, 123B) that connect the plurality of torsion deformation parts to each other. In conventional movable devices, where the drive unit displaces the connection point between the drive unit and the movable unit, causing the movable unit to rotate around its pivot axis, bending deformation occurs at the connection point between one end of the drive unit and the other end of the drive unit, with a curvature center axis parallel to the pivot axis of the movable unit. In such conventional movable devices, increasing the rigidity of the connection point to increase the range of rotation of the movable unit increases the stress due to the bending deformation of the connection point, and the connection point becomes more prone to breakage at the point where the stress is concentrated. Conversely, lowering the rigidity of the connection point against bending deformation reduces the stress due to the bending deformation of the connection point and distributes that stress, making the connection point less likely to break. However, in this case, even if the connection point between the drive unit and the drive unit is displaced, the connection point bends significantly, reducing the amount of displacement at the connection point between the movable unit and the drive unit, thus reducing the range of rotation of the movable unit. On the other hand, a movable device can be conceivable in which the drive unit displaces the connection point between the movable part and the connecting part, causing torsional deformation in the connecting part and rotating the movable part around a pivot axis parallel to the torsional axis of the connecting part. With such a movable device, the movable part can be rotated while suppressing the bending deformation of the connecting part, which has a curvature center axis parallel to the pivot axis of the movable part, thus preventing the connecting part from breaking due to bending deformation. However, in such a movable device, in order to increase the range of rotation of the movable part, the amount of torsional deformation of the connecting part must be increased. Therefore, when the movable part is rotated by only a single torsional axis, if the range of rotation of the movable part is increased, the amount of torsional deformation around the torsional axis will increase, and the stress due to torsional deformation will become too large, making the connecting part prone to breaking. Therefore, in the connection part of this embodiment, multiple torsion deformation parts are provided that deform torsionally around a torsion axis extending in a direction substantially parallel to the rotation axis of the movable part, and these multiple torsion deformation parts are connected to each other by a connecting beam. With this configuration, since the movable part is rotated by torsion deformation around multiple torsion axes, even if the range of rotation of the movable part is increased, the amount of torsion deformation of each individual torsion deformation part can be made smaller than when the movable part is rotated by torsion deformation around a single torsion axis. Thus, even if the range of rotation of the movable part is increased, the connection part is less likely to break.

[0075] [Second aspect] The second aspect is characterized in that, in the first aspect, the connecting portion includes drive-side connecting beam portions 125A, 125B that connect the end of the drive-side torsion deformation portion (for example, the second torsion deformation portion 122A, 122B) of the plurality of torsion deformation portions that is opposite to the end connected to the connecting beam portion, to the connection portion in the drive unit. According to this, it is easy to form a structure in which the torsional deformation part on the drive unit side of the multiple torsional deformation parts is connected to the connection part of the drive unit.

[0076] [Third aspect] The third aspect is characterized in that, in the second aspect, the connecting portion includes a folded structure in which the connecting beam portion on the drive unit side and the connecting beam portion connected to the torsional deformation portion on the drive unit side are located on the same side with respect to the torsional axis of the torsional deformation portion on the drive unit side. According to this, the length of the movable device in the longitudinal direction of the connecting beam can be shortened, thereby making the movable device smaller.

[0077] [Fourth aspect] The fourth aspect is characterized in that, in any of the first to third aspects, the connecting portion includes a connecting beam portion on the movable portion side (for example, a mirror portion side connecting beam portion 124) that connects the end of the torsion deformation portion on the movable portion side of the plurality of torsion deformation portions (for example, the first torsion deformation portions 121A, 121B) opposite to the end connected to the connecting beam portion with the connection portion in the movable portion. According to this, it is easy to form a structure that connects the torsion deformation part on the movable side of the multiple torsion deformation parts to the connection part of the movable part.

[0078] [Fifth aspect] The fifth aspect is characterized in that, in the fourth aspect, the connecting portion includes a folded structure in which the connecting beam portion on the movable portion side and the connecting beam portion connected to the torsion deformation portion on the movable portion side are located on the same side with respect to the torsion axis of the torsion deformation portion on the movable portion side. According to this, the length of the movable device in the longitudinal direction of the connecting beam can be shortened, thereby making the movable device smaller.

[0079] [Sixth aspect] The sixth embodiment is characterized in that, in any of the first to fifth embodiments, the connecting portion is an integral structure formed from a single substrate (e.g., an SOI substrate), and the length of the torsion deformation portion in a direction perpendicular to the torsion axis and parallel to the substrate surface of the single substrate (e.g., displacement transmission path width Lt1, Lt2) is shorter than the length of the connecting beam portion in a direction perpendicular to the longitudinal direction of the connecting beam portion and parallel to the substrate surface of the single substrate (e.g., displacement transmission path width Ls1). According to this, even when the connecting beam section and the torsion deformation section are formed from the same substrate and have the same thickness, it is possible to obtain a characteristic in which the torsion rigidity of the torsion deformation section is lower than the bending rigidity of the connecting beam section. As a result, the displacement loss due to the bending deformation of the connecting beam section can be suppressed.

[0080] [Seventh aspect] The seventh embodiment is characterized in that, in any of the first to sixth embodiments, it has second drive units 110b, 110d that drive the movable part to rotate around a second pivot axis (e.g., a second axis) having an axis direction different from the axis direction of the pivot axis (e.g., a first axis), and the connecting part includes other torsion deformation parts (e.g., third torsion deformation parts 126A, 126B) that torsion deform around a torsion axis O3 extending in a direction substantially parallel to the second pivot axis. According to this, when the movable part rotates around the second pivot axis due to the drive of the second drive unit, the twist around the second pivot axis that occurs at the connection can be absorbed by the torsional deformation of the other torsion deformation unit having a torsion axis substantially parallel to the second pivot axis. Therefore, by lowering the torsional rigidity of the other torsion deformation unit, the resistance force of the connection unit against the twist around the second pivot axis can be kept small, and the narrowing of the rotational range of the movable part around the second pivot axis due to the resistance force of the connection unit can be suppressed.

[0081] [8th aspect] The eighth aspect is characterized in that, in any of the first to seventh aspects, the connecting portion has an asymmetric structure with respect to a virtual line passing through the connecting portion of the movable portion. Even with such an asymmetrical structure, it is possible to obtain a connection that is less prone to breakage even when the range of rotation of the movable part is increased. [Explanation of Symbols]

[0082] 11: Control device 13: Movable device 14: Reflective surface 101: Mirror section 101a~101d: Connection points 110a~110d: Drive unit 111a~111d: Drive unit base 112a~112d: Piezoelectric drive unit 113a~112d: Connection points 120a~120d, 120a': Connection part 121A, 121B: First torsional deformation section 122A, 122B: Second torsional deformation section 123A, 123B: Intermediate connecting beam part 124: Mirror section side connecting beam section 125A, 125B: Drive unit side connecting beam section 126A, 126B: Third torsional deformation section 140: Support frame 150: Electrode connection part 161: Silicon support layer 162: Silicon oxide layer 163: Silicon Active Layer 301: Lower electrode 302: Piezoelectric part 303: Upper electrode O1~O3: Torsion shaft [Prior art documents] [Patent Documents]

[0083] [Patent Document 1] Japanese Patent Publication No. 2024-015968

Claims

1. Movable parts and A drive unit for driving the aforementioned movable part, It has a connecting part that connects the movable part and the drive part, A movable device in which the drive unit displaces the connection portion with the connecting portion, thereby displacing the connection portion of the movable part with the connecting portion, and thereby rotating the movable part around a pivot axis, The aforementioned connection part is Multiple torsion deformation parts that are torsionally deformed around a torsion axis extending in a direction substantially parallel to the rotation axis due to the displacement of the connection part in the drive unit, A movable device characterized by including a connecting beam portion that connects the plurality of torsion deformation portions to one another.

2. In the movable device according to claim 1, The movable device is characterized in that the connecting portion includes a connecting beam portion on the drive unit side that connects the end of the torsional deformation portion on the drive unit side of the plurality of torsional deformation portions that is opposite to the end connected to the connecting beam portion with the connection portion on the drive unit.

3. In the movable device according to claim 2, The movable device is characterized in that the connecting portion includes a folding structure in which the connecting beam portion on the drive unit side and the connecting beam portion connected to the torsional deformation portion on the drive unit side are located on the same side with respect to the torsional axis of the torsional deformation portion on the drive unit side.

4. In the movable device according to any one of claims 1 to 3, The movable device is characterized in that the connecting portion includes a connecting beam portion on the movable side that connects the end of the torsion deformation portion on the movable side of the plurality of torsion deformation portions that is opposite to the end that is connected to the connecting beam portion, and the connecting portion on the movable part.

5. In the movable device according to claim 4, The movable device is characterized in that the connecting portion includes a folding structure in which the connecting beam portion on the movable portion side and the connecting beam portion connected to the torsion deformation portion on the movable portion side are located on the same side with respect to the torsion axis of the torsion deformation portion on the movable portion side.

6. In the movable device according to any one of claims 1 to 3, The aforementioned connection portion is an integrated structure formed from a single substrate. A movable device characterized in that the length of the torsion deformation portion in a direction perpendicular to the torsion axis and parallel to the substrate surface of the single substrate is shorter than the length of the connecting beam portion in a direction perpendicular to the longitudinal direction of the connecting beam portion and parallel to the substrate surface of the single substrate.

7. In the movable device according to any one of claims 1 to 3, The device has a second drive unit that drives the movable part to rotate around a second pivot axis having an axis different from the axis of the pivot axis, The movable device is characterized in that the connecting portion includes another torsion deformation portion that deforms to the torsion around a torsion axis extending in a direction substantially parallel to the second pivot axis.

8. In the movable device according to any one of claims 1 to 3, The movable device is characterized in that the connecting portion has an asymmetric structure with respect to a virtual line passing through the connecting portion of the movable portion.

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