Movable device, projection device, moving body, head-mounted display, head-up display, laser headlamp, object recognition apparatus, position detection apparatus, and movable method

Abstract

To further reduce the oscillation of a movable part.SOLUTION: A movable device 13 comprises: a movable part; a drive part that drives the movable part; and a control part that applies a drive voltage to the drive part. The drive voltage includes a basic periodic waveform comprising: a first waveform that has a continuously increasing amplitude during a first period Ta; a second waveform that has a continuously decreasing amplitude during a second period Tb that follows the first period Ta; and a third waveform that is shorter than the total of the first period and the second period, and that has a waveform with a continuously increasing amplitude and a waveform with a continuously decreasing amplitude during a third period Tc that follows the second period Tb.SELECTED DRAWING: Figure 11

Description

Technical Field

[0001] The present invention relates to a movable device, a projection device, a moving body, a head-mounted display, a head-up display, a laser headlamp, an object recognition device, a position detection device, and a moving method.

Background Art

[0002] A method for driving a scanning beam device including a scanning element is known (see, for example, Patent Document 1). In the method described in Patent Document 1, a driving signal including an amplitude part (first part) and an amplitude part (second part) is used to drive the scanning element. In this method, for the increasing amplitude part (first part) of the driving signal, a decreasing amplitude part (second part) of the driving signal with a phase inversion is provided relatively, for the purpose of quickly removing the energy stored in the resonating scanning element and stopping the scanning of the scanning element in a short time.

Summary of the Invention

Problems to be Solved by the Invention

[0003] In the prior art, when reducing the oscillation of a movable part, the reduction of the oscillation may be insufficient.

[0004] An object of the present invention is to provide a movable device capable of further reducing the oscillation of a movable part.

Means for Solving the Problems

[0005] A movable device according to an aspect of the present invention includes: a movable part; a driving part for driving the movable part; a control part for applying a driving voltage to the driving part, and the driving voltage is a first waveform whose amplitude continuously increases in a first period; a second waveform whose amplitude continuously decreases in a second period after the first period; In a third period after the second period, there is a third waveform having a waveform in which the amplitude continuously increases and is shorter than the sum of the first period and the second period, and a waveform in which the amplitude continuously decreases. It includes a basic periodic waveform including the above.

Effect of the Invention

[0006] According to the present invention, it is possible to provide a movable device capable of further reducing the swing of the movable part.

Brief Description of the Drawings

[0007]

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Embodiments for Carrying Out the Invention

[0008] Hereinafter, embodiments for carrying out the invention will be described with reference to the drawings. In each drawing, the same reference numerals are assigned to the same constituent parts, and redundant explanations may be omitted.

[0009] In the following description of the embodiments, rotation, oscillation, and movement are considered synonymous. In each figure, the X-axis direction, Y-axis direction, and Z-axis direction that are orthogonal to each other may be shown. The Z-axis direction is along the stacking direction of each layer in the piezoelectric drive unit or the like. The case of viewing in the Z-axis direction may be described as "plan view". Also, in each figure, parallel hatching may be applied to a portion that is not a cross-section.

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

[0011] [Movable device 13 according to the first embodiment] With reference to FIGS. 1 to 3, the movable device 13 according to the first embodiment will be described. FIG. 1 is a plan view illustrating the movable device 13 according to the first embodiment of the present invention. FIG. 2 is an end view of the movable device 13 along the second axis in FIG. 1. FIG. 3 is a cross-sectional view showing a cut surface along line III-III in FIG. 1.

[0012] As shown in FIG. 1, the movable device 13 includes a mirror unit 101, drive units 110a, 110b, a first support frame 120, drive units 130a, 130b, a second support frame 140, an electrode connection unit 150, and a control device 11.

[0013] The mirror unit 101 has a reflecting surface 14 that reflects incident light. The mirror unit 101 is an example of a movable part. 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.

[0014] 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 part 150 is electrically connected to the first driving units 110a and 110b, the second driving units 130a and 130b, and the control device 11.

[0015] The movable device 13 is formed, for example, by etching a single SOI (Silicon On Insulator) substrate and forming the reflecting surface 14, the first piezoelectric driving units 112a and 112b, the second piezoelectric driving units 131a to 131f and 132a to 132f, the electrode connection part 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 the SOI substrate is formed, or may be performed during the formation of the SOI substrate.

[0016] As shown in FIGS. 2 and 3, the SOI substrate on which the movable device 13 is formed includes a silicon support layer 161 made of single-crystalline 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-crystalline silicon formed on the silicon oxide layer 162. The silicon oxide layer 162 can also be referred to as a BOX (Buried Oxide) layer.

[0017] The member composed only of the silicon active layer 163 has a function as an elastic part having elasticity.

[0018] The SOI substrate does not necessarily have to be planar and may have curvature or the like. The member used for forming the movable device 13 can be integrally formed by an etching process or the like, and may be a substrate having partial elasticity, and is not limited to the SOI substrate.

[0019] The mirror unit 101 includes, for example, a circular mirror unit base 102 and a reflecting surface 14 formed on the surface of the mirror unit base on the +Z side. The mirror unit base 102 includes, for example, a silicon active layer 163. The reflecting surface 14 includes, for example, a metal thin film containing aluminum, gold, silver, or the like.

[0020] A movable thick portion 103 for reinforcing the mirror unit is formed on the surface of the mirror unit base 102 on the -Z side. The movable thick portion 103 includes, for example, a silicon support layer 161 and a silicon oxide layer 162, and can suppress the distortion of the reflecting surface 14 caused by movement.

[0021] As shown in FIG. 1, the first drive units 110a and 110b include torsion bars 111a and 111b and first piezoelectric drive units 112a and 112b.

[0022] Each of the torsion bars 111a and 111b has one end connected to the mirror unit 101, and is an example of a support portion that extends in the first axial direction and elastically supports the mirror unit 101.

[0023] Each of the first piezoelectric drive units 112a and 112b has one end connected to the torsion bars 111a and 111b, and is an example of a drive beam that swings the mirror unit 101 around the first axis by deforming the torsion bars 111a and 111b. The first axis is an example of a predetermined swing axis. The other ends of each of the first piezoelectric drive units 112a and 112b are respectively connected to the inner peripheral portion of the first support frame 120. The first drive units 110a and 110b also include detection piezoelectric elements 160a and 160b.

[0024] As shown in FIG. 3, the torsion bars 111a and 111b include a silicon active layer 163. Further, in the first piezoelectric drive units 112a and 112b, a lower electrode 301, a piezoelectric part 302, and an upper electrode 303 are 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 contain, for example, gold (Au) or platinum (Pt). The piezoelectric part 302 contains, for example, PZT (lead zirconate titanate) which is a piezoelectric material.

[0025] As shown in FIGS. 1 and 3, the first support frame 120 is a rectangular support formed 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 part 101.

[0026] The second drive units 130a and 130b include a plurality of second piezoelectric drive units 131a to 131f and 132a to 132f connected so as to be folded back. One end of the second drive units 130a and 130b is connected to the outer peripheral part of the first support frame 120, and the other end is connected to the inner peripheral part of the second support frame 140.

[0027] The connection point between the second drive unit 130a and the first support frame 120 and the connection point between the second drive unit 130b and the first support frame 120 are point-symmetrical with respect to the center of the reflection surface 14. Further, the connection point between the second drive unit 130a and the second support frame 140 and the connection point between the second drive unit 130b and the second support frame 140 are point-symmetrical with respect to the center of the reflection surface 14.

[0028] As shown in FIG. 2, in the second piezoelectric drive units 131a to 131f and 132a to 132f, a lower electrode 201, a piezoelectric part 202, and an upper electrode 203 are laminated in this order on the +Z side surface of the silicon active layer 163 which is an elastic part. The upper electrode 203 and the lower electrode 201 contain, for example, gold (Au) or platinum (Pt). The piezoelectric part 202 contains, for example, PZT (lead zirconate titanate) which is a piezoelectric material.

[0029] As shown in FIGS. 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 so as to surround the mirror part 101, the first drive parts 110a and 110b, the first support frame 120, and the second drive parts 130a and 130b.

[0030] The electrode connection part 150 is formed on the +Z side surface of the second support frame 140, and is electrically connected to each upper electrode 303 and each lower electrode 301 of the first piezoelectric drive parts 112a and 112b, each upper electrode 203 and each lower electrode 201 of the second piezoelectric drive parts 131a to 131f and 132a to 132f, and the control device 11 via electrode wirings such as aluminum (Al). A signal voltage is applied to the lower electrode 201, and the upper electrode 203 is grounded (GND).

[0031] Note that each of the upper electrode 203 or the lower electrode 201 may be directly connected to the electrode connection part 150, or may be indirectly connected by connecting the electrodes to each other or the like.

[0032] In this embodiment, the case where the piezoelectric part 202 is formed only on one surface (+Z side surface) of the silicon active layer 163 which is an elastic part has been described as an example, but it may be provided on another surface of the elastic part (for example, -Z side surface), or may be provided on both one surface and the other surface of the elastic part.

[0033] Further, if the mirror part 101 can be driven around the first axis or the second axis, the shapes of the respective components are not limited to the shapes of the embodiment. For example, the torsion bars 111a and 111b, and the first piezoelectric drive parts 112a and 112b may have a shape with curvature.

[0034] Furthermore, an insulating layer made of a silicon oxide film may be formed on at least any one of the +Z side surfaces of the upper electrodes 303 of the first drive parts 110a and 110b, the +Z side surface of the first support frame, the +Z side surfaces of the upper electrodes 203 of the second drive parts 130a and 130b, and the +Z side surface of the second support frame.

[0035] In this case, electrode wirings are provided on the insulating layer, and only connection spots where the upper electrodes 203, 303, the lower electrodes 201 or 301 and the electrode wirings are connected are formed as openings by partially removing the insulating layer or not forming the insulating layer. This increases the design freedom of the first driving units 110a, 110b, the second driving units 130a, 130b, and the electrode wirings, and can suppress short circuits due to contact between electrodes. Further, the silicon oxide film also functions as an antireflection material.

[0036] Further, a detection piezoelectric element 160a for detecting elastic deformation of the first driving unit 110a is provided close to the first piezoelectric driving unit 112a. Further, a detection piezoelectric element 160b for detecting elastic deformation of the first driving unit 110b is provided close to the first piezoelectric driving unit 112b.

[0037] The first piezoelectric driving unit 112a is provided in the first driving unit 110a and deforms the first driving unit 110a according to the applied driving voltage. The first piezoelectric driving unit 112b is provided in the first driving unit 110b and deforms the first driving unit 110b according to the applied driving voltage.

[0038] The detection piezoelectric element 160a generates a detection signal by the piezoelectric effect according to the deformation of the first driving unit 110a and outputs it to the control device 11 via the electrode connection unit 150. The detection piezoelectric element 160b generates a detection signal by the piezoelectric effect according to the deformation of the first driving unit 110b and outputs it to the control device 11 via the electrode connection unit 150.

[0039] <Control by the control device 11> Next, the control by the control device 11 will be described. The control device 11 has a control unit 30 (see FIG. 28) that applies driving voltages to the first driving units 110a, 110b and the second driving units 130a, 130b of the movable device of the movable device 13.

[0040] The piezoelectric parts 302 included in the first drive parts 110a and 110b, and the piezoelectric parts 202 included in the second drive parts 130a and 130b exhibit the so-called inverse piezoelectric effect in which deformation (for example, expansion and contraction) proportional to the potential of the applied voltage occurs when a positive or negative voltage is applied in the polarization direction. The first drive parts 110a and 110b, and the second drive parts 130a and 130b move the mirror part 101 using the inverse piezoelectric effect.

[0041] In this case, the angle formed by the XY plane and the reflecting surface 14 when the reflecting surface 14 of the mirror part 101 is inclined 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 is defined as the negative deflection angle.

[0042] In the first drive parts 110a and 110b, when drive voltages are applied in parallel to the piezoelectric parts 302 included in the first piezoelectric drive parts 112a and 112b via the upper electrodes 303 and the lower electrodes 301, the respective piezoelectric parts 302 are deformed. Due to the action caused by the deformation of the piezoelectric parts 302, the first piezoelectric drive parts 112a and 112b are bent and deformed. As a result, a driving force around the first axis acts on the mirror part 101 through the twisting of the two torsion bars 111a and 111b, and the mirror part 101 swings around the first axis. The drive voltages applied to the first drive parts 110a and 110b are controlled by the control device 11.

[0043] By the control device 11 applying drive voltages having a predetermined sine wave waveform in parallel to the first piezoelectric drive parts 112a and 112b included in the first drive parts 110a and 110b, the mirror part 101 can be moved around the first axis at the period of the drive voltage having the predetermined sine wave waveform.

[0044] The control device 11 can also control the swinging of the first drive parts 110a and 110b based on information regarding the swinging of the first drive parts 110a and 110b obtained from the detection signals output by the detection piezoelectric elements 160a and 160b respectively.

[0045] For example, when the frequency of the driving voltage is set to approximately 20 kHz which is about the same as the resonance frequency of the torsion bars 111a and 111b, the mirror unit 101 can be resonantly vibrated at approximately 20 kHz by utilizing the mechanical resonance caused by the twisting of the torsion bars 111a and 111b.

[0046] The movable device 13 according to the first embodiment may be 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. The movable device 13 is not limited thereto. The movable device 13 only needs to be able to swing the mirror unit 101 by the piezoelectric unit 202 to which a driving voltage is applied. The movable device 13 may be of, for example, a type with both ends supported (both-cantilever).

[0047] [Movable Device 13 According to the Second Embodiment] Next, the movable device 13 according to the second embodiment will be described. FIG. 4 is a plan view illustrating the movable device 13 according to the second embodiment of the present invention. The difference between the movable device 13 of the second embodiment and the movable device 13 according to the first embodiment is that it includes first drive units 210a and 210b instead of the first drive units 110a and 110b. In the description of the second embodiment, the same description as that of the first embodiment will be omitted.

[0048] The first drive unit 210a includes a torsion bar 211a and first piezoelectric drive units 212a and 212c. The first piezoelectric drive unit 212a extends from the torsion bar 211a in the +X direction. The first piezoelectric drive unit 212c extends from the torsion bar 211a in the -X direction.

[0049] The first drive unit 210b includes a torsion bar 211b and first piezoelectric drive units 212b and 212d. The first piezoelectric drive unit 212b extends from the torsion bar 211b in the +X direction. The first piezoelectric drive unit 212d extends from the torsion bar 211b in the -X direction. Thus, the movable device 13 may be of a both-cantilever type. The movable device 13 may also be one that moves the reflecting surface 14 only in one axial direction.

[0050] [Movable device 13 according to the third embodiment] Next, the movable device 13 according to the third embodiment will be described. FIG. 5 is a plan view illustrating the movable device 13 according to the third embodiment of the present invention. The movable device 13 includes four drive units 110a to 110d and is capable of two-dimensionally deflecting light. The movable device 13 according to the third embodiment is suitable for vector scan, Lissajous scan, and spiral scan. The drive units 110a to 110d are examples of the first drive unit and the second drive unit.

[0051] In the description of the third embodiment, the same description as that of the movable device 13 according to the above first and second embodiments may be omitted. The driving method of the driving body is not limited to piezoelectric driving. The driving method of the driving body may be electrostatic driving, electromagnetic driving, or thermoelectric driving. In the movable device 13, the movable part and the drive units 110a to 110d are formed on the same substrate. The movable part and the drive part can be implemented, for example, in the silicon active layer of an SOI substrate, but the in-plane and thickness-direction configurations are not limited to the description of the embodiment.

[0052] The movable device 13 shown in FIG. 5 includes a mirror part (movable part) 101, a support part 140, and drive units 110a to 110d. The support part 140 may be a frame body having a rectangular shape in plan view. The rectangular frame body has sides along the X-axis direction and the Y-axis direction in plan view.

[0053] The drive units 110a to 110d are respectively arranged corresponding to the corner parts of the support part 140. The drive unit 110a has a torsion bar 111a and a piezoelectric drive unit 112a. The piezoelectric drive unit 112a is formed to have a rectangular shape in plan view. The torsion bar 111a projects from the piezoelectric drive unit 112a toward the mirror part 101. Similarly, the drive unit 110b has a torsion bar 111b and a piezoelectric drive unit 112b. The drive unit 110c has a torsion bar 111c and a piezoelectric drive unit 112c. The drive unit 110d has a torsion bar 111d and a piezoelectric drive unit 112d.

[0054] [Movable device 13 according to the fourth embodiment] Next, the movable device 13 according to the fourth embodiment will be described. FIG. 6 is a plan view illustrating the movable device 13 according to the fourth embodiment of the present invention. The difference between the movable device 13 according to the fourth embodiment shown in FIG. 6 and the movable device 13 according to the third embodiment shown in FIG. 5 is that the detection piezoelectric elements 160a to 160d are provided. The detection piezoelectric elements 160a to 160d are collectively referred to as the detection piezoelectric element 160. In the description of the fourth embodiment, the same descriptions as those of the first to third embodiments are omitted.

[0055] The first drive unit 110a includes a torsion bar 111a, a first piezoelectric drive unit 112a, and a detection piezoelectric element 160a. The detection piezoelectric element 160a is formed on the first piezoelectric drive unit 112a. The longitudinal direction of the detection piezoelectric element 160a may be the same as the longitudinal direction of the torsion bar 111a. The detection piezoelectric element 160a may be disposed, for example, on an extension line of the torsion bar 111a. A plurality of detection piezoelectric elements 160a may be formed on the first piezoelectric drive unit 112a.

[0056] Similarly, the first drive unit 110b includes a torsion bar 111b, a first piezoelectric drive unit 112b, and a detection piezoelectric element 160b. The first drive unit 110c includes a torsion bar 111c, a first piezoelectric drive unit 112c, and a detection piezoelectric element 160c. The first drive unit 110d includes a torsion bar 111d, a first piezoelectric drive unit 112d, and a detection piezoelectric element 160d.

[0057] The detection piezoelectric element 160a outputs a detection signal corresponding to the deformation of the first drive unit 110a to the control device 11. The detection piezoelectric element 160b outputs a detection signal corresponding to the deformation of the first drive unit 110b to the control device 11. The detection piezoelectric element 160c outputs a detection signal corresponding to the deformation of the first drive unit 110c to the control device 11. The detection piezoelectric element 160d outputs a detection signal corresponding to the deformation of the first drive unit 110c to the control device 11.

[0058] [Drive signal for spiral scan according to the comparative example] Next, the drive signal for the spiral scan according to the comparative example will be described. FIG. 7 is a waveform diagram showing the drive signal for the spiral scan according to the comparative example. After FIG. 7, as an example, for a movable device having four piezoelectric drive units, the drive waveforms applied to the respective piezoelectric drive units are shown. The movable device has a plurality of piezoelectric drive units and can apply drive signals of the types necessary to swing the plurality of piezoelectric drive units. For example, in the movable device shown in FIGS. 1 to 4, a drive waveform may be applied to the piezoelectric drive unit.

[0059] In FIG. 7, the horizontal axis represents the passage of time, and the vertical axis represents the amplitude normalization amount of the drive waveform. The "amplitude normalization amount" is a value proportional to the amplitude of the drive waveform, and the maximum value of the amplitude of the drive waveform is set to "1". In FIG. 6, the drive waveform corresponding to the basic period is shown. In FIG. 7, the drive waveforms applied to the piezoelectric drive units 112a to 112d are respectively illustrated. The phases of the four high-speed signals supplied to the piezoelectric drive units 112a to 112d are shifted by 90 degrees each. The basic period refers to the minimum unit of repetition of the drive waveform input to the movable device 13.

[0060] The drive waveform corresponding to the basic period has a plurality of high-speed signal period waveforms. The wavelength of the high-speed signal period waveform is shorter than the wavelength of the basic period waveform. The basic period waveform has a first period and a second period. In the first period, the amplitude of the high-speed signal period waveform continuously increases. When the amplitude of the high-speed signal period waveform reaches the maximum, the first period ends. After the end of the first period, the second period starts. In the second period, the amplitude of the high-speed signal period waveform continuously decreases.

[0061] [Problems of the spiral scan according to the comparative example] FIG. 8 is a graph showing changes in the mirror swing amount in the X-axis direction when a drive signal for spiral scan according to a comparative example is input. In FIG. 8, the horizontal axis represents time, and the vertical axis represents a value obtained by normalizing the mirror swing amount in the X-axis direction with the maximum value. In FIG. 8, the maximum value of the mirror swing amount is set to "1". The resonant vibration energy of the high-speed signal periodic waveform does not completely drop to 0, and the mirror swing amount does not return to the angular resolution of 0 within one period of the basic period. As a result, the resolution on the center side within the angular resolution region becomes low and cavitation occurs, while the resolution on the outer peripheral side of the angular resolution region becomes high. "Angular resolution 0" means the case where the mirror swing amount is 0. "The center side within the angular resolution region" refers to the vicinity of the angular resolution center O.

[0062] When spiral scan is used for image projection, it is considered desirable that the resolution of the angular resolution center O corresponding to the center of the field of view be high. It is desirable that the resolution of the light trajectory within the angular resolution region be controllable.

[0063] FIG. 9 is a graph showing the ratio of the cavity diameter to the overall angular resolution of the movable device according to the comparative example. FIG. 9 is a graph showing the ratio of the Q value to the high-speed signal frequency fs and the ratio of the cavity diameter to the overall angular resolution of the movable device according to the comparative example. The high-speed signal frequency fs is defined as the frequency of the high-speed signal periodic waveform. In FIG. 9, the horizontal axis represents Q value / fs, and the vertical axis represents the ratio of the cavity diameter to the overall angular resolution. "Overall angular resolution" refers to the case where the mirror swing amount is the maximum value. "Cavity diameter" refers to the outer diameter of the region where the resolution of the light trajectory is low and cavitation occurs in the vicinity of the angular resolution center O. In FIG. 8, the cases where the high-speed signal frequency fs is 1000 Hz or less, 2500 Hz or less, 5000 Hz or less, and 10000 Hz or less are shown.

[0064] According to the ratio of the cavity diameter to the overall imaging angle shown in FIG. 9, it can generally be seen that, regardless of the high-speed signal frequency fs, by decreasing Q / fs, it is possible to increase the resolution at the imaging angle center O. However, it is difficult to selectively design the Q value of the movable device. Also, designing the Q value can cause problems such as a significant change in the size of the movable structure in the movable device 13 or a large decrease in the swing angle. Therefore, it is desirable that the resolution can be controlled by the drive waveform rather than the movable structure itself of the movable device 13.

[0065] [Drive Signal for Spiral Scan According to the First Reference Example] FIG. 10 is a waveform diagram showing the drive signal for spiral scan according to the first reference example. In FIG. 10, the horizontal axis represents the passage of time, and the vertical axis represents the amplitude normalization amount of the drive waveform. In FIG. 10, the drive signals applied to the piezoelectric drive units 112a to 112d are each illustrated. The phases of the four drive signals supplied to the piezoelectric drive units 112a to 112d are shifted by 90 degrees each. The drive signal shown in FIG. 9 is a drive waveform corresponding to the basic period.

[0066] [Amplitude Modulation] FIG. 11 is a diagram showing the drive signal of the basic period applied to the piezoelectric drive unit 112a. The amplitude modulation in the high-speed signal period waveform shown in FIG. 11 will be described. In FIG. 11, the horizontal axis represents the passage of time, and the vertical axis represents the amplitude normalization amount of the drive waveform. The drive signal shown in FIG. 11 is a drive waveform corresponding to the basic period, and within the basic period, it includes a first period Ta, a second period Tb, and a fourth period Tc in this order.

[0067] The first period Ta is a period in which the amplitude of the drive voltage continuously increases and continues until the amplitude becomes maximum. The second period Tb is a period in which the amplitude of the drive voltage continuously decreases. The fourth period Tc is a period in which the amplitude of the drive voltage is a predetermined value. The predetermined value of the amplitude in the fourth period Tc is equal to or less than the value of the smallest amplitude in the second period immediately before the fourth period. In the fourth period Tc, the amplitude of the drive voltage may be 0.

[0068] The drive signal includes a first waveform within a first period Ta. The drive signal includes a second waveform within a second period Tb. The drive signal includes a fourth waveform within a fourth period Tc. The phases of the drive signals of the first waveform and the second waveform may be in-phase or in antiphase. The fourth waveform may be a DC waveform. In the case of a drive waveform with a constant amplitude of the drive voltage in the fourth waveform, it may be in-phase or in antiphase with the phase of the second waveform.

[0069] Also, it is preferable that the transition of the amplitude of the drive waveform from the first period Ta to the second period Tb is continuous. Similarly, it is preferable that the transition of the amplitude of the drive waveform from the second period Tb to the fourth period Tc is continuous. In the first period Ta, the amplitude of the drive waveform increases, the swing of the reflecting surface 14 increases, and the energy of the resonant vibration accumulates. In the second period Tb, the amplitude of the drive waveform decreases, and the swing of the reflecting surface 14 attenuates. In the second period Tb, the amplitude of the drive signal input to the piezoelectric drive unit 112a is smoothly decreased. In the fourth period Tc, the period during which the amplitude of the drive signal is a predetermined value continues for a certain time. The certain time is set to be one cycle or more of the high-speed signal period.

[0070] [Effect of the drive signal according to the first reference example] In this way, by having the drive signal (drive voltage) of the basic periodic waveform include a first waveform whose amplitude continuously increases within the first period Ta, a second waveform whose amplitude continuously decreases within the second period Tb, and a fourth waveform whose amplitude is a predetermined value within the fourth period Tc, it is possible to attenuate the swing of the reflecting surface 14 toward the center O of the angular range without increasing unnecessary resonant energy during the time other than the effective scanning period. Also, when using the first period Ta during the effective scanning period for projecting an image, by making the first period Ta longer than the second period Tb, a large amount of resonant energy can be obtained, and a high angular resolution can be achieved. The "effective scanning period" is the period of the range in which the trajectory of light is drawn while the reflecting surface 14 is irradiated with light.

[0071] FIG. 12 is a graph showing the ratio of the amplitude increase period to the amplitude decrease period according to the first reference example and the ratio of the cavity diameter to the overall angular field of view of the movable device 13. In FIG. 12, when the length of the basic period and the length of the first period Ta, which is the amplitude increase period, are fixed, the horizontal axis shows the ratio of the length of the first period Ta to the length of the second period Tb, and the vertical axis shows the ratio of the cavity region diameter to the overall angular field of view. When the length of the second period Tb is short, that is, when the length of the fourth period Tc, where the amplitude is a predetermined value, is long, the ratio of the cavity diameter to the overall angular field of view is smaller compared to the case where the length of the second period Tb is long, that is, when the length of the fourth period Tc is short. "When the length of the basic period and the length of the first period Ta are fixed" means that the ratio of the "first period Ta" to the "basic period" is constant and does not change.

[0072] When the ratio of the "first period Ta" to the "basic period" is constant, by shortening the second period Tb and lengthening the fourth period Tc, the resolution of the angular field center O can be increased. Thereby, by changing the ratio of the "fourth period Tc" to the "basic period", it is possible to control the resolution of the trajectory of the reflected light by the reflecting surface 14.

[0073] FIG. 13 is a diagram showing the actual trajectory of light when a drive signal according to the comparative example is input. The trajectory is the trajectory drawn by the light reflected by the reflecting surface 14 on the irradiation surface in response to the drive of the mirror part 101, which is the movable part, when light is incident on the reflecting surface 14. The light reflected by the reflecting surface 14 spreads while swirling spirally outward from the angular field center O, and then draws a trajectory that narrows while swirling spirally inward toward the angular field center O. When a drive signal for spiral scan according to the comparative example is input, the resolution near the angular field center O is rough. When a drive signal for spiral scan according to the comparative example is input, the resolution near the angular field center O is rougher than the resolution at a position away from the angular field center O. When a drive signal for spiral scan according to the comparative example is input, the reduction of the swing of the movable part is insufficient, and it is difficult to achieve a high frame rate.

[0074] FIG. 14 is a diagram showing the trajectory of light when a drive signal for spiral scan according to the first reference example is input. As shown in FIG. 14, when a drive signal for spiral scan according to the first reference example is input, the resolution on the side of the imaging angle center O can be increased as compared with the case of the drive signal of the comparative example shown in FIG. 13.

[0075] According to the drive signal for spiral scan according to the first reference example, since the mirror swing amount converges to the imaging angle center O, it is possible to draw a spiral with an interval substantially equal to the interval between the spirals in other regions even near the imaging angle center O. As a result, the aperture diameter of the imaging angle center O can be reduced, so that the resolution of the image formed on the irradiation surface can be increased by using the light reflected by the reflecting surface 14.

[0076] The drive signal for spiral scan according to the first reference example can be applied to, for example, the movable device 13 according to the third embodiment. The movable device 13 according to the third embodiment includes a mirror unit (movable unit) 101, a support unit that supports the mirror unit 101, a frame body to which the support unit is connected, drive units 110a to 110d that are disposed on the support unit and drive the mirror unit 101, and a control device (control unit) 11 that applies a drive signal (drive voltage) including a predetermined waveform to the drive units 110a to 110d at a predetermined basic period. The drive signal for spiral scan according to the first reference example may be applied to, for example, the movable device 13 according to the first and second embodiments, or may be applied to the movable device 13 of other forms.

[0077] The drive signal of the basic period according to the first reference example includes a first waveform whose amplitude continuously increases in the first period Ta, a second waveform whose amplitude continuously decreases in the second period Tb after the first period Ta, and a fourth waveform whose amplitude is a predetermined value in the fourth period Tc after the second period Tb. The predetermined value in the amplitude of the fourth waveform is set to be equal to or less than the value of the smallest amplitude among the second waveforms in the second period immediately before the fourth period.

[0078] In the movable device 13, by applying a drive signal including a third waveform to the drive units 110a to 110d, the swing amount of the mirror unit 101 can be made smaller than at the end of the second period Tb. In the movable device 13, the swing of the mirror unit 101 can be further reduced. As a result, since the mirror swing amount easily returns to the angular resolution of 0 within one cycle of the basic period, the resolution on the side of the angular resolution center O can be increased.

[0079] In the fourth period Tc, the amplitude of the fourth waveform is a predetermined value, and the predetermined value may be equal to or less than the value of the smallest amplitude among the second waveforms in the second period Tb immediately before the fourth period Tc. As shown in FIG. 11, in the drive waveform according to the first reference example, the amplitude of the fourth waveform in the fourth period Tc is equal to or less than the value of the smallest amplitude among the second waveforms in the second period Tb. By setting the amplitude of the fourth waveform to be equal to or less than the value of the smallest amplitude among the second waveforms in the second period immediately before the fourth period, the swing of the mirror unit 101 can be reduced more efficiently.

[0080] The fourth waveform may be a DC waveform or have an amplitude of 0. By setting the fourth waveform to be a DC waveform or having an amplitude of 0, the swing of the mirror unit 101 can be reduced more efficiently.

[0081] The length of the second period Tb is preferably shorter than the length of the first period Ta. In other words, the length of the first period Ta is preferably longer than the length of the second period Tb. In the drive waveform according to the first reference example, the first period Ta is longer than the second period Tb.

[0082] [Drive Signal for Spiral Scan According to the First Embodiment] FIGS. 15 and 16 are waveform diagrams showing drive signals for spiral scan according to the first embodiment. In FIG. 15, drive signals applied to the piezoelectric drive units 112a to 112d are shown. FIG. 16 shows a drive signal of the basic period applied to the piezoelectric drive unit 112a. In FIGS. 15 and 16, the horizontal axis represents the passage of time, and the vertical axis represents the amplitude normalization amount of the drive waveform. The drive signals shown in FIGS. 15 and 16 are drive waveforms corresponding to the basic period. In the description of the first embodiment, the same description as that of the first reference example may be omitted.

[0083] The drive signal shown in FIG. 16 includes a first period Ta, a second period Tb, and a third period Th within a basic period. The first period Ta, the second period Tb, and the third period Th follow in this order. The first period Ta is a period in which the amplitude of the drive waveform continuously increases. The second period Tb is a period in which the amplitude of the drive waveform continuously decreases. The third period Th includes a period Te and a period Tf in this order. The third period Th is shorter than the sum of the first period Ta and the second period Tb, and is a period having a waveform in which the amplitude continuously increases and a waveform in which the amplitude continuously decreases. Note that, among the third period Th, the period Te is a period in which the amplitude of the drive waveform continuously increases, and the period Tf is a period in which the amplitude of the drive waveform continuously decreases.

[0084] The drive signal includes a first waveform within the first period Ta. The drive signal includes a second waveform within the second period Tb. The drive signal includes a third waveform within the third period Th. The phases of the drive signals of the first waveform and the second waveform may be in phase or in antiphase.

[0085] The phase of the third waveform shown in FIG. 16 is shifted by 180 degrees with respect to the phase of the first waveform. That is, the third waveform is in antiphase with respect to the first waveform. By having the drive signal with the antiphase third waveform, the oscillation of the mirror unit 101 can be reduced more efficiently than in the first reference example.

[0086] Further, the control device 11 may determine the drive waveform of the third waveform based on the information regarding the oscillation of the mirror unit 101 acquired from the detection signal generated by the detection piezoelectric element 160. The control device 11 may estimate the oscillation of the mirror unit 101 from the detection signal and determine the phase of the third waveform so as to cancel the unintended oscillation of the mirror unit 101. As a result, the unintended oscillation of the mirror unit 101 can be suppressed more accurately. When using this method, the phase of the third waveform may be in phase or in antiphase with the phase of the first waveform.

[0087] The maximum amplitude of the third waveform may be the same as the maximum amplitude of the first waveform, or may be smaller than the maximum amplitude of the first waveform.

[0088] Also, it is preferable that the change in amplitude from the first period Ta to the second period Tb is continuous. Similarly, it is preferable that the change in amplitude from the second period Tb to the period Te is continuous. It is preferable that the change in amplitude from the period Te to the period Tf is continuous.

[0089] [Effect of the drive signal according to the first embodiment] FIG. 17 is a diagram showing the trajectory of light when a drive signal for spiral scan according to the first embodiment is input. As shown in FIG. 17, when a drive signal for spiral scan according to the first embodiment is input, the resolution on the side of the imaging angle center O can be increased as compared with the case of the drive signal of the comparative example shown in FIG. 13.

[0090] In the first embodiment, by applying a periodic waveform signal having a phase difference of approximately 180 deg with respect to the oscillation of the resonated mirror unit 101 to the piezoelectric drive units 112a to 112d, the piezoelectric drive units 112a to 112d can be moved so as to cancel the oscillation of the resonance. As a result, the vibration of the mirror unit 101 can be quickly attenuated, the cavity of the light trajectory near the imaging angle center O can be reduced, and the imaging angle center O can be made to have a high resolution. By applying the drive signal according to the first embodiment to the piezoelectric drive units 112a to 112d, the resolution of the trajectory can be controlled.

[0091] The drive signal according to the first embodiment includes a third waveform having, in the third period Th after the second period Tb, a waveform (period Te) in which the amplitude continuously increases and a waveform (period Tf) in which the amplitude continuously decreases, and is shorter than the sum of the first period Ta and the second period Tb. In the drive signal of the first embodiment, the resonance vibration can be suppressed more efficiently.

[0092] In the drive signal according to the first embodiment, the maximum amplitude of the third waveform in the periods Te and Tf may be the same as the maximum amplitude of the first waveform in the first period Ta, or may be smaller than the maximum amplitude of the first waveform. For example, if the amplitude of the third waveform is made excessively large, there is a possibility that the resonant vibration of the mirror unit 101 will increase during the period Te. However, by making the maximum amplitude of the third waveform smaller than the maximum amplitude of the first waveform, it is possible to suppress an increase in the vibration of the mirror unit 101 during the period Te.

[0093] The drive signal for spiral scan according to the first embodiment can be applied, for example, to the movable device 13 according to the third and fourth embodiments. The movable device 13 according to the third and fourth embodiments includes a first drive unit that swings the mirror unit 101 around the first axis 1 and a second drive unit that swings the mirror unit 101 around the second axis 2. The control device 11 can control the phase difference between the drive signal applied to the first drive unit and the drive signal applied to the second drive unit. Thereby, the locus of the light reflected by the mirror unit 101 can be controlled. The piezoelectric drive units 112a to 112d are examples of the first drive unit and the second drive unit. The drive signal for spiral scan according to the first embodiment may be applied, for example, to the movable device 13 according to the first and second embodiments, or may be applied to movable devices 13 of other forms.

[0094] [Drive Signal for Spiral Scan According to the Second Embodiment] FIGS. 18 and 19 are waveform diagrams showing the drive signal for spiral scan according to the second embodiment. FIG. 18 shows the drive signals applied to the piezoelectric drive units 112a to 112d. FIG. 19 shows the drive signal of the basic period applied to the piezoelectric drive unit 112a. In FIGS. 18 and 19, the horizontal axis represents the passage of time, and the vertical axis represents the amplitude normalization amount of the drive waveform. The drive signals shown in FIGS. 18 and 19 are drive waveforms corresponding to the basic period. In the description of the second embodiment, the same description as the above first embodiment may be omitted.

[0095] The drive signal shown in FIG. 19 includes a first period Ta, a second period Tb, a third period Th, and fourth periods Td and Tg within a basic period. The third period Th includes a period Te and a period Tf. The first period Ta, the second period Tb, and the periods Te and Tf follow in this order. The fourth periods Td and Tg may be provided as the fourth period Td between the second period Tb and the period Te, or may be provided as the fourth period Tg after the period Tf. The fourth periods Td and Tg are periods in which the amplitude of the drive waveform is a predetermined value. It is preferable that the transition of the amplitude from the second period Tb to the fourth period Td is continuous. Similarly, it is preferable that the transition of the amplitude from the period Tf to the fourth period Tg is continuous.

[0096] The drive signal includes a fourth waveform within the fourth periods Td and Tg. In the fourth waveform, the fourth period Td and the fourth period Tg may have different drive waveforms. The predetermined value of the amplitude of the fourth waveform in the fourth period Td is equal to or less than the value of the smallest amplitude among the second waveforms of the second period Tb immediately preceding the fourth period Td. The predetermined value of the amplitude of the fourth waveform in the fourth period Tg is equal to or less than the value of the smallest amplitude among the third waveforms of the third period Tf immediately preceding the fourth period Tg.

[0097] In the drive signal shown in FIG. 18, the phase of the third waveform is shifted by 180 degrees with respect to the phase of the first waveform. The phase of the third waveform may be in phase with the phase of the first waveform, similar to the first embodiment.

[0098] [Effect of the Drive Signal According to the Second Embodiment] FIG. 20 is a diagram showing the trajectory of light when the drive signal for spiral scanning according to the second embodiment is input. As shown in FIG. 20, when the drive signal for spiral scanning according to the second embodiment is input, the resolution on the side of the imaging angle center O can be increased as compared with the case of the drive signal of the comparative example shown in FIG. 13.

[0099] In the second embodiment, similar to the first embodiment, the vibration of the mirror unit 101 can be quickly attenuated, the cavity of the light trajectory near the imaging angle center O can be reduced, and the imaging angle center O can be made to have a high resolution.

[0100] The drive signal according to the second embodiment is different from the first embodiment in that it includes a fourth period Td after the second period Tb and a fourth period Tg after the third period Tf. With the drive signal of the second embodiment, resonance vibration can be suppressed more efficiently.

[0101] Note that in the drive signal according to the modification, the fourth periods Td and Tg may include a period in which a constant amplitude continues and a period in which the drive waveform becomes a DC waveform. By setting the fourth periods Td and Tg in the drive signal, resonance vibration can be suppressed more efficiently. In the drive signal according to the modification, only one of the fourth period Tg and the fourth period Td may be set.

[0102] Similar to the first embodiment, the drive signal for spiral scan according to the second embodiment can be applied to the movable device 13 according to, for example, the third and fourth embodiments. Thereby, the locus of the light reflected by the mirror unit 101 can be controlled. The drive signal for spiral scan according to the second embodiment may be applied to the movable device 13 according to, for example, the first and second embodiments, or may be applied to the movable device 13 of other forms.

[0103] In the modification, the fourth waveform may be a DC waveform. Or the amplitude of the fourth waveform may be 0. By making the fourth waveform a DC waveform or making the amplitude of the fourth waveform 0, the swing of the mirror unit 101 can be reduced more efficiently.

[0104] [Relationship between high-speed signal frequency fs, fundamental frequency ffps, first resonance frequency f1, and second resonance frequency f2] When the frequency of the basic periodic waveform is the basic frequency \(f_{fps}\), the relationships among the high-speed signal frequency \(f_s\), the first resonance frequency \(f_1\), and the second resonance frequency \(f_2\) will be described. The first resonance frequency \(f_1\) is the resonance frequency at which the mirror unit 101 oscillates around the first axis 1. The second resonance frequency \(f_2\) is the resonance frequency at which the mirror unit 101 oscillates around the second axis 2. The basic frequency \(f_{fps}\) is preferably set such that \(f_s + Nf_{fps}\) and \(f_s - Nf_{fps}\) do not coincide with \(f_1\) and \(f_2\). Here, \(N\) is an arbitrary natural number. The first resonance frequency \(f_1\) and the second resonance frequency \(f_2\) are preferably the same value.

[0105] [Basic Frequency and High-Speed Signal Frequency in the First Embodiment] In the first embodiment, the basic period includes large waves (Ta and Tb) and small waves (Te and Tf). In the first embodiment, the frequency with respect to the basic period is the basic frequency. When waves of the same magnitude occur, one period is defined there. In the first embodiment, the high-speed signal frequencies of the large waves and the small waves are the same. Therefore, there is no problem whichever frequency is used as the high-speed signal frequency.

[0106] [Relationship among High-Speed Signal Frequency \(f_s\), Basic Frequency \(f_{fps}\), First Resonance Frequency \(f_1\), and Second Resonance Frequency \(f_2\) (Case 1)] FIG. 21 is a schematic diagram showing an example (Case 1) of the relationship among the high-speed signal frequency \(f_s\), the basic frequency \(f_{fps}\), the first resonance frequency \(f_1\), and the second resonance frequency \(f_2\).

[0107] The high-speed signal frequency \(f_s\) is a value between the first resonance frequency \(f_1\) and the second resonance frequency \(f_2\). The second resonance frequency \(f_2\) is a frequency higher than the first resonance frequency \(f_1\). The first resonance frequency \(f_1\) is greater than the value obtained by subtracting the high-speed signal frequency \(f_s\) from the basic frequency \(f_{fps}\). The second resonance frequency \(f_2\) is less than the value obtained by adding the high-speed signal frequency \(f_s\) to the basic frequency \(f_{fps}\).

[0108] The control device 11 can apply a drive signal that satisfies the above conditions to the piezoelectric drive units 112a to 112d. When the first resonance frequency f1 or the second resonance frequency f2 coincides with the frequency obtained by subtracting an exponentially multiplied value of the fundamental frequency ffps from the high-speed signal frequency fs, the distortion in the trajectory of the spiral scan light becomes strong. According to the drive signal that satisfies the above conditions, the distortion in the trajectory of the spiral scan light can be suppressed.

[0109] [Relationship among the high-speed signal frequency fs, the fundamental frequency ffps, the first resonance frequency f1, and the second resonance frequency f2 (Case 2)] FIG. 22 is a schematic diagram showing an example (Case 2) of the relationship among the high-speed signal frequency fs, the fundamental frequency ffps, the first resonance frequency f1, and the second resonance frequency f2.

[0110] The high-speed signal frequency fs is a value higher than both the values of the first resonance frequency f1 and the second resonance frequency f2. The first resonance frequency f1 and the second resonance frequency f2 are values that do not coincide with the frequency obtained by subtracting an integer multiple value of the fundamental frequency ffps from the high-speed signal frequency fs.

[0111] The control device 11 can apply a drive signal that satisfies the above conditions to the piezoelectric drive units 112a to 112d. According to the drive signal that satisfies the above conditions, the distortion in the trajectory of the spiral scan light can be suppressed.

[0112] [Relationship among the high-speed signal frequency fs, the fundamental frequency ffps, the first resonance frequency f1, and the second resonance frequency f2 (Case 3)] FIG. 23 is a schematic diagram showing an example (Case 3) of the relationship among the high-speed signal frequency fs, the fundamental frequency ffps, the first resonance frequency f1, and the second resonance frequency f2.

[0113] The high-speed signal frequency fs is a value lower than both the values of the first resonance frequency f1 and the second resonance frequency f2. The first resonance frequency f1 and the second resonance frequency f2 are values that do not coincide with the frequency obtained by adding an integer multiple value of the fundamental frequency ffps to the high-speed signal frequency fs.

[0114] The control device 11 can apply a drive signal that satisfies the above conditions to the piezoelectric drive units 112a to 112d. According to the drive signal that satisfies the above conditions, distortion in the trajectory of the light during spiral scanning can be suppressed.

[0115] [Movable device 13 according to the fifth embodiment] FIG. 24 is a plan view illustrating the movable device 13 according to the fifth embodiment. In the description of the movable device 13 according to the fifth embodiment, descriptions similar to those of the movable device 13 according to the above embodiment may be omitted. The movable device 13 according to the fifth embodiment includes a support portion 120 and drive portions 110a to 110c. The support portion 120 is a frame body that forms a circle in plan view. The drive portions 110a to 110c are arranged with a 120° shift from each other.

[0116] The drive portion 110a has a torsion bar 111a and a piezoelectric drive portion 112a. The drive portion 110b has a torsion bar 111b and a piezoelectric drive portion 112b. The drive portion 110c has a torsion bar 111c and a piezoelectric drive portion 112c. The piezoelectric drive portions 112a to 112c are arranged, for example, in an arc shape.

[0117] The movable device 13 according to the fifth embodiment includes a first drive portion 110a that swings the mirror portion 101 around the first axis U, a second drive portion 110b that swings the mirror portion 101 around the second axis V, and a third drive portion 110c that swings the mirror portion 101 around the third axis W. The first axis U and the second axis V intersect at 120°. The second axis V and the third axis W intersect at 120°. The third axis W and the first axis U intersect at 120°.

[0118] The control device 11 can control the phase differences of the drive signals applied to the first drive unit 110a, the drive signal applied to the second drive unit 110b, and the drive signal applied to the third drive unit 110c. Thereby, the trajectory of the light reflected by the mirror unit 101 can be controlled. The piezoelectric drive units 112a to 112c are examples of the first drive unit, the second drive unit, and the third drive unit. The movable device 13 according to the fifth embodiment may include, for example, a three-phase movable structure. The three-phase movable structure is a structure including the first drive unit, the second drive unit, and the third drive unit. The movable device 13 having a three-phase movable structure can obtain a natural vibration that draws a circle, and thus is suitable for spiral scanning.

[0119] The movable device 13 according to the modification may have, for example, a six-phase movable structure. The six-phase movable structure is a structure including the first drive unit, the second drive unit, the third drive unit, the fourth drive unit, the fifth drive unit, and the sixth drive unit. The first drive unit, the second drive unit, the third drive unit, the fourth drive unit, the fifth drive unit, and the sixth drive unit may be shifted by, for example, 60 degrees each. The movable device 13 having a six-phase movable structure can obtain a natural vibration that draws a circle, and thus is suitable for spiral scanning.

[0120] [Movable Device 13 According to the Sixth Embodiment] FIG. 25 is a plan view illustrating the movable device 13 according to the sixth embodiment of the present invention. In the description of the movable device 13 according to the sixth embodiment, the description similar to that of the movable device 13 according to the above embodiment may be omitted. The movable device 13 according to the sixth embodiment includes a mirror unit 101, a support unit 120, and drive units 110a and 110b. The support unit 120 is a frame body that forms a circle in plan view.

[0121] The drive unit 110a includes a torsion bar 111a, piezoelectric drive units 112a and 113a, and a connection part 114a. The drive unit 110b includes a torsion bar 111b, piezoelectric drive units 112b and 113b, and a connection part 114b. The torsion bars 111a and 111b elastically support the mirror unit 101. The connection parts 114a and 114b are formed so as to project inward from the support part 120. The connection part 114a connects the piezoelectric drive units 112a and 113a to the support part 120. The connection part 114b connects the piezoelectric drive units 112b and 113b to the support part 120.

[0122] The piezoelectric drive units 112a and 113a and the piezoelectric drive units 112b and 113b are arc-shaped in a plan view. The piezoelectric drive units 112a and 113a and the piezoelectric drive units 112b and 113b are formed concentrically with the mirror unit 101. The piezoelectric drive units 112a and 113a form a meander structure connected in a folded-back manner. The piezoelectric drive units 112b and 113b form a meander structure connected in a folded-back manner. Note that the "piezoelectric drive unit" may be referred to as a "drive beam".

[0123] The movable device 13 according to the sixth embodiment may have a meander structure. According to the movable device 13 according to the sixth embodiment, complex resolution control is possible as compared with a conventional movable device. The "resolution control" may be control of the drive displacement of the mirror unit 101.

[0124] [Optical Scanning System] Next, an optical scanning system 10 to which the movable device 13 is applied will be described. FIG. 26 is a schematic diagram of an example of the optical scanning system. The optical scanning system 10 is a system that deflects the light irradiated from the light source device 12 according to the control of the control device 11 by the reflecting surface 14 of the movable device 13 and optically scans the surface to be scanned 15.

[0125] The optical scanning system 10 includes the movable device 13. The movable device 13 has a control device 11, a light source device 12, and a reflecting surface 14.

[0126] The control device 11 is an electronic circuit unit including, for example, a CPU (Central Processing Unit) and an FPGA (Field-Programmable Gate Array). The movable device 13 is, for example, a MEMS device having a reflecting surface 14, and the reflecting surface 14 is movable.

[0127] The light source device 12 is, for example, a laser device that irradiates a laser. The surface to be scanned 15 is, for example, a screen.

[0128] The control device 11 generates control commands for the light source device 12 and the movable device 13 based on the acquired light scanning information. The control device 11 outputs drive signals to the light source device 12 and the movable device 13 based on the control commands. The light source device 12 irradiates light from the light source based on the input drive signal. The movable device 13 can swing the reflecting surface 14 around the X-axis based on the input drive signal. The movable device 13 can swing the reflecting surface 14 around the Y-axis based on the input drive signal. The movable device 13 may swing the reflecting surface 14 around an axis extending in other directions.

[0129] The optical scanning system 10 can project the light reflected by the reflecting surface 14 onto the surface to be scanned 15 by swinging the reflecting surface 14 and perform optical scanning. The optical scanning system 10 can project an arbitrary image onto the surface to be scanned 15.

[0130] [Hardware Configuration of Optical Scanning System 10] Next, a hardware configuration of an example of the optical scanning system 10 will be described. FIG. 27 is a hardware configuration diagram of an example of the optical scanning system 10. The control device 11, the light source device 12, and the movable device 13 are electrically connected to each other. 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.

[0131] The CPU 20 is an arithmetic unit that reads programs and data from a storage device such as the ROM 22 onto the RAM 21, executes processing, and realizes the overall control and functions of the control device 11. The RAM 21 is a volatile storage device that temporarily holds programs and data. The ROM 22 is a non-volatile storage device that can hold programs and data even when the power is turned off. The ROM 22 stores the processing programs and data that the CPU 20 executes to control the respective functions of the optical scanning system 10.

[0132] The FPGA 23 is a circuit that outputs control signals suitable for the light source device driver 25 and the movable device driver 26 according to the processing of the CPU 20. The external I / F 24 is an interface with, for example, an external device or a network. The external devices include, for example, upper devices such as a PC (Personal Computer), storage devices such as a USB memory, an SD card, a CD, a DVD, an HDD, and an SSD. The network is, for example, an automotive CAN (Controller Area Network), a LAN (Local Area Network), the Internet, etc. The external I / F 24 may be configured to enable connection or communication with an external device, and an external I / F 24 may be prepared for each external device.

[0133] The light source device driver 25 is an electric circuit that outputs drive signals such as a drive voltage to the light source device 12 according to the input control signal. The movable device driver 26 is an electric circuit that outputs drive signals such as a drive voltage to the movable device 13 according to the input control signal.

[0134] 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 as long as the CPU 20 can acquire optical scanning information, the configuration may be such that the optical scanning information is stored in the ROM 22 or the FPGA 23 in the control device 11, or a new storage device such as an SSD may be provided in the control device 11 and the optical scanning information may be stored in that storage device.

[0135] The light scanning information is information indicating how to perform light scanning on the scanned surface 15. For example, when displaying an image by light scanning, the light scanning information may be image data. Also, for example, when performing light writing by light scanning, the light scanning information is writing data indicating the writing order and writing location. For example, when performing object recognition by light scanning, the light scanning information is irradiation data indicating the timing and irradiation range for irradiating light for object recognition.

[0136] The control device 11 can realize the functional configuration described later according to the instructions of the CPU 20 and the hardware configuration.

[0137] [Functional Configuration of Control Device 11] Next, the functional configuration of the control device 11 of the light scanning system 10 will be described. FIG. 28 is a functional block diagram of an example of the control device 11. The control device 11 includes a control unit 30 and a drive signal output unit 31. The control unit 30 is realized by, for example, the CPU 20, the FPGA 23, etc. The control unit 30 acquires light scanning information from an external device, converts the light 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 as light scanning information from an external device or the like, generates a control signal from the image data by a predetermined process, and outputs it to the drive signal output unit 31. The drive signal output unit 31 is realized by a light source device driver 25, a movable device driver 26, etc. The drive signal output unit 31 outputs a drive signal to the light source device 12 or the movable device 13 based on the input control signal.

[0138] The drive signal is a signal for controlling the drive of the light source device 12 or the movable device 13. For example, the drive signal output to the light source device 12 is a drive voltage for controlling the irradiation timing and irradiation intensity of the light source. The drive signal output to the movable device 13 is a drive voltage for controlling the timing and movable range for moving the reflecting surface 14. The drive signal output to the movable device 13 may be the drive signal according to the above-described first embodiment or the drive signal according to the second embodiment.

[0139] [Process of Light Scanning] Next, the process of the optical scanning system 10 for optically scanning the scanned surface 15 will be described. FIG. 29 is a flowchart of an example of the process related to the optical scanning system.

[0140] 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 drive units 110a to 1110d of 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 drive units 110a to 110d of the movable device 13 swing the reflecting surface 14 based on the input drive signal. According to the optical scanning system 10, by driving the light source device 12 and the movable device 13, light is deflected in an arbitrary direction and optically scanned.

[0141] Note that the optical scanning system 10 may separately include a control device 11 that controls the drive units 110a to 110d of the movable device 13 and a control device that controls the light source device 12.

[0142] According to the optical scanning system 10, a decrease in the resonance frequency that occurs when enlarging the mirror unit 101, which is a movable part, can be suppressed. According to the optical scanning system 10, optical scanning can be performed with high precision.

[0143] [Head-up display device] Next, the head-up display device 500 will be described. FIG. 30 is a schematic diagram of an example of an automobile 400 equipped with the head-up display device 500. The automobile 400 is equipped with the head-up display device 500. The head-up display device 500 is an image projection device that projects an image by optical scanning. The automobile 400 is an example of a moving body.

[0144] As shown in FIG. 30, the head-up display device 500 is installed, for example, near the windshield (such as the front glass 401) of the automobile 400. The projection light L emitted from the head-up display device 500 is reflected by the front glass 401 and directed toward the observer (driver 402) who is the user. Thereby, the driver 402 can visually recognize an image or the like 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 be made to visually recognize a virtual image by the projection light reflected by the combiner.

[0145] FIG. 31 is a schematic diagram of an example of the head-up display device 500. The head-up display device 500 includes laser light sources 501R, 501G, and 501B. The laser light source 501R emits red laser light. The laser light source 501G emits green laser light. The laser light source 501B emits blue laser light.

[0146] The head-up display device 500 includes an incident optical system. The incident optical system includes collimator lenses 502, 503, and 504, two dichroic mirrors 505 and 506, and a light quantity adjustment unit 507. The collimator lenses 502 to 504 are provided for the laser light sources 501R, 501G, and 501B. The laser light emitted from the laser light sources 501R, 501G, and 501B enters the movable device 13 through the incident optical system. The laser light that has entered the movable device 13 is reflected by the reflection surface 14. The laser light is deflected by the movable device 13.

[0147] The head-up display device 500 includes a projection optical system. The projection optical system includes a free-form surface mirror 509, an intermediate screen 510, and a projection mirror 511. The laser light deflected by the movable device 13 is projected onto the front glass 401 through the projection optical system. The head-up display device 500 may project the laser light onto the screen. The head-up display device 500 may include a light source unit 530 that has an optical housing and is unitized. The optical housing houses, for example, laser light sources 501R, 501G, 501B, collimator lenses 502, 503, 504, and dichroic mirrors 505, 506.

[0148] The head-up display device 500 can project the intermediate image displayed on the intermediate screen 510 onto the front glass 401. According to the head-up display device 500, the intermediate image projected onto the front glass 401 can be visually recognized by the driver 402 as a virtual image.

[0149] The laser light of each color emitted from the laser light sources 501R, 501G, 501B is made into substantially parallel light by the collimator lenses 502, 503, 504, respectively, and is combined by two dichroic mirrors 505, 506. The dichroic mirrors 505, 506 may each be an example of a combining unit. After the combined laser light is adjusted in light quantity by the light quantity adjustment unit 507, it is two-dimensionally scanned by the movable device 13. The projection light L two-dimensionally scanned by the movable device 13 is reflected by the free-form surface mirror 509 to correct distortion, and then is condensed onto the intermediate screen 510. The intermediate screen 510 displays an intermediate image. The intermediate screen 510 is composed of a microlens array in which microlenses are two-dimensionally arranged. The intermediate screen 510 enlarges the incident projection light L in units of microlenses.

[0150] The movable device 13 swings (reciprocally moves) the reflecting surface 14 in two axial directions. The movable device 13 two-dimensionally scans the projection light L incident on the reflecting surface 14. The drive control of the movable device 13 is performed in synchronization with the light emission timings of the laser light sources 501R, 501G, 501B.

[0151] The image projection device can project an image by performing optical scanning with a movable device 13 having a reflecting surface 14. The image projection device may be, for example, a projector placed on a desk or the like and projecting an image on a display screen. The image projection device may also be a head-mounted display device mounted on a wearing member worn on the head of an observer or the like, and projecting an image on a reflective-transmissive screen of the wearing member or projecting an image using the eyeball as a screen.

[0152] The image projection device is not limited to being mounted on a vehicle or a wearing member. The image projection device may be, for example, mounted on a moving body such as an aircraft, a ship, a mobile robot, etc. The image projection device may also be mounted on a non-moving body such as a working robot that operates a drive target such as a manipulator without moving from its position.

[0153] The image projection device including the movable device 13 can suppress a decrease in the resonance frequency that occurs when enlarging the movable part and can perform optical scanning with high precision. According to the image projection device including the movable device 13, the resolution of the light locus near the center O of the angular field of view can be improved.

[0154] [Optical writing device 600] Next, the optical writing device 600 including the movable device 13 will be described. FIG. 32 is a schematic diagram of an example of an image forming apparatus equipped with the optical writing device 600. The image forming apparatus may be a laser printer 650. The laser printer 650 has a printer function using laser light. The laser printer 650 includes the optical writing device 600. The optical writing device 600 optically scans a photoreceptor drum, which is a surface to be scanned 15, with one or a plurality of laser beams. The optical writing device 600 performs optical writing on the photoreceptor drum by performing optical scanning. The optical writing device 600 includes the movable device 13.

[0155] FIG. 33 is a schematic diagram of an example of the optical writing device. In the optical writing device 600, the laser light emitted 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-axis direction or two-axis direction by the movable device 13.

[0156] The optical writing device 600 includes a scanning optical system 602. The scanning optical system has a first lens 602a, a second lens 602b, and a reflection mirror unit 602c. The laser beam deflected by the movable device 13 is irradiated onto the surface to be scanned 15 (for example, a photoreceptor drum or a photosensitive paper) through the scanning optical system 602. Thereby, the optical writing device 600 performs optical writing on the surface to be scanned 15. The scanning optical system 602 forms an image of the light beam in a spot shape on the surface to be scanned 15. As described above, the control device 11 applies a drive signal to the drive units 110a to 110d of the movable device 13 to swing the reflection surface 14.

[0157] In this way, the optical writing device 600 can be applied to an image forming device having a printer function using a laser beam. The image forming device equipped with the optical writing device 600 may be a laser label device. The optical writing device 600 includes a scanning optical system capable of optical scanning in two axial directions, and may be mounted on an image forming device such as a laser label device that deflects a laser beam onto a thermal medium for optical scanning and printing by heating.

[0158] The movable device 13 having the reflection surface 14 consumes less power for driving compared to a rotating polygon mirror using a polygon mirror or the like. According to the optical writing device 600 including the movable device 13, power saving can be achieved. The wind noise during the vibration of the movable device 13 is smaller than that of the rotating polygon mirror. Therefore, according to the optical writing device 600 including the movable device 13, the quietness can be improved. The installation space of the movable device 13 is overwhelmingly smaller compared to the installation space of the rotating polygon mirror. The heat generation amount of the movable device 13 is overwhelmingly smaller compared to the heat generation amount of the rotating polygon mirror. According to the image forming device including the optical writing device 600, the entire device can be easily miniaturized.

[0159] In this way, by applying the movable device 13 of the embodiment to the optical writing device 600, it is possible to suppress a decrease in the resonance frequency that occurs when enlarging the movable part, and to provide an optical writing device capable of optical scanning with high precision. According to the optical writing device 600 including the movable device 13, the resolution of the light trajectory near the center O of the angular field can be improved.

[0160] [Laser Radar Device] Next, the laser radar device 700 will be described. FIGS. 34 and 35 are schematic views of an example of an automobile equipped with the laser radar device 700. FIG. 36 is a schematic view of an example of the laser radar device 700. The laser radar device 700 is a distance measuring device that measures the distance to an object in the target direction. The distance measuring device is an example of an object recognition device. The laser radar device 700 has a movable device 13. The laser radar device 700 is mounted on, for example, an automobile 701, scans the target direction with light, and receives the reflected light from the object 702 existing in the target direction, thereby measuring the distance to the object 702. The automobile 701 is an example of a moving body.

[0161] As shown in FIG. 36, the laser radar device 700 includes an incident optical system. The incident optical system has a collimator lens 703 and a plane mirror 704. The collimator lens 703 is an optical system that makes divergent light into substantially parallel light. The laser light emitted from the light source device 12 passes through the incident optical system and is scanned in one-axis or two-axis directions by the movable device 13.

[0162] The laser radar device 700 includes a light projecting optical system having a light projecting lens 705. The light reflected by the reflecting surface 14 of the movable device 13 passes through the light projecting lens 705 and irradiates the object 702 in front. The control device 11 drives and controls the light source device 12 and the movable device 13. The reflected light reflected by the object 702 is detected by the photodetector 709. The reflected light is received by the imaging element 707 through a condensing lens 706 or the like which is an incident light detection and light receiving optical system. The imaging element 707 outputs a detection signal to the 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 the distance measurement circuit 710.

[0163] The distance measurement circuit 710 recognizes the presence or absence of the object 702 based on the time difference between the timing when the light source device 12 emits laser light and the timing when the photodetector 709 receives the laser light, or the phase difference for each pixel of the received imaging device 707, and calculates the distance information to the object 702.

[0164] The movable device 13 having the reflecting surface 14 is less likely to be damaged compared to a polygonal mirror and is small in size, so a small and highly durable radar device can be provided. Such a lidar device can be attached to, for example, vehicles, aircraft, ships, robots, etc., and can optically scan a predetermined range to measure the presence or absence of obstacles and the distance to the obstacles.

[0165] The distance measurement device performs optical scanning by controlling the movable device 13 having the reflecting surface 14 with the control device 11, and measures the distance to the object 702 by receiving the reflected light with a photodetector. The object recognition device is not limited to the distance measurement device. The object recognition device may include the movable device 13, perform optical scanning, and be able to detect the object 702 by receiving the reflected light with a photodetector.

[0166] The object recognition device may be, for example, a biometric authentication device that calculates object information such as shape from the distance information obtained by optically scanning a hand or face, and recognizes the object by recording and referring to it. The object recognition device may be a security sensor that recognizes an intruder by optical scanning of a target range. The object recognition device may also be a 3D scanner that calculates and recognizes object information such as shape from the distance information obtained by optical scanning and outputs it as 3D data.

[0167] By providing such a distance measurement device with the movable device 13, it is possible to suppress a decrease in the resonance frequency that occurs when enlarging the movable part, and to perform optical scanning with high precision. According to the distance measurement device provided with the movable device 13, it is possible to improve the resolution of the light trajectory near the center O of the angular field of view.

[0168] [Laser headlamp] Next, the laser headlamp 50 including the movable device 13 will be described. FIG. 37 is a schematic diagram of an example of the laser headlamp 50. The laser headlamp 50 may be a headlight of an automobile. The laser headlamp 50 includes a light source device 12b, a movable device 13, a mirror 51, and a transparent plate 52. The movable device 13 may include a control device 11 which is a control unit.

[0169] The light source device 12b is a light source that emits blue laser light. The light emitted from the light source device 12b enters the movable device 13 and is reflected by the reflecting surface 14. The drive units 110a to 110d of the movable device 13 swing the reflecting surface 14 based on a signal from the control device 11. The movable device 13 swings the reflecting surface 14 to two-dimensionally scan the laser light in the XY directions.

[0170] The scanned light by the movable device 13 is reflected by the mirror 51 and enters the transparent plate 52. The transparent plate 52 is coated with a yellow phosphor on its front or back surface. When the blue laser light reflected by the mirror 51 passes through the coating of the yellow phosphor on the transparent plate 52, it changes to white within the range defined as the color of the headlight. Thereby, the front of the automobile equipped with the laser headlamp 50 is illuminated with white light.

[0171] The scanned light by the movable device 13 undergoes predetermined scattering when passing through the phosphor of the transparent plate 52. Thereby, the glare in the illumination target in front of the automobile is alleviated.

[0172] In the laser headlamp 50, the colors of the light source device 12b and the phosphor are not limited to blue and yellow respectively. The laser headlamp 50 may include a light source device 12b that emits near-ultraviolet light. In the laser headlamp 50, the transparent plate 52 may be coated with a mixture of phosphors of blue, green, and red which are the primary colors of light. According to the laser headlamp 50 having this configuration, the light passing through the transparent plate 52 can be converted to white, and the front of the automobile can be illuminated with white light.

[0173] By providing such a laser head lamp 50 with the movable device 13, it is possible to suppress a decrease in the resonance frequency that occurs when increasing the movable part, and perform optical scanning with high precision. According to the laser head lamp 50 provided with the movable device 13, it is possible to improve the resolution of the optical trajectory near the center O of the angle of view.

[0174] [Head-Mounted Display] Next, the head-mounted display 60 will be described. FIG. 38 is a perspective view of the appearance of an example of the head-mounted display. FIG. 39 is a diagram partially illustrating the configuration of the head-mounted display. The head-mounted display 60 is a head-mounted display that can be worn on a human head. The head-mounted display 60 can have, for example, a shape similar to glasses. Hereinafter, the head-mounted display may be abbreviated as HMD. The HMD 60 includes the movable device 13.

[0175] The HMD 60 includes a front 60a and a temple 60b provided in a substantially symmetric manner in a pair on the left and right. The front 60a has, for example, a light guide plate 61. The temple 60b can incorporate an optical system, a control device 11, and the like.

[0176] In FIG. 39, the left-eye part of the HMD 60 is illustrated. Among the HMD 60, the right-eye part has the same configuration as the left-eye part. The HMD 60 includes a light source unit 530, a light quantity adjustment unit 507, a movable device 13, a light guide plate 61, and a half mirror 62. The movable device 13 may include the control device 11 as a control unit.

[0177] As described above, the light source unit 530 is unitized by the optical housing. The optical housing houses the laser light sources 501R, 501G, 501B, the collimator lenses 502, 503, 504, and the dichroic mirrors 505, 506. In the light source unit 530, the three-color laser lights emitted from the laser light sources 501R, 501G, 501B are combined by the dichroic mirrors 505, 506. The light source unit 530 emits the combined parallel light.

[0178] The light emitted from the light source unit 530 is adjusted in light quantity by the light quantity adjuster 507 and then enters the movable device 13. The movable device 13 swings the reflecting surface 14 based on the drive signal input from the control device 11. The movable device 13 two-dimensionally scans the light incident from the light source unit 530. The control device 11 drives and controls the drive units 110a to 110d of the movable device 13 in synchronization with the light emission timings of the laser light sources 501R, 501G, 501B. The HMD 60 forms a color image with the scanned light.

[0179] The scanned light by the movable device 13 is incident on the light guide plate 61. The light guide plate 61 guides the scanned light to the half mirror 62 while reflecting it on the inner wall surface. The light guide plate 61 is formed of a resin or the like having transparency with respect to the wavelength of the scanned light.

[0180] The half mirror 62 reflects the light from the light guide plate 61 to the back side of the HMD 60 and emits it in the direction of the eyes of the wearer 63 of the HMD 60. The half mirror 62 has, for example, a free-form surface shape. The image by the scanned light is formed on the retina of the wearer 63 by reflection by the half mirror 62. Alternatively, the HMD 60 forms an image on the retina of the wearer 63 by reflection by the half mirror 62 and the lens effect of the crystalline lens in the eyeball. In the HMD 60, the spatial distortion in the image is corrected by reflection by the half mirror 62. The wearer 63 can observe the image formed by the light scanned in the XY directions.

[0181] By including the half mirror 62, the HMD 60 enables the wearer 63 to observe an image in which an image formed by light from the outside world and an image formed by the scanning light are superimposed. The HMD 60 may include a mirror instead of the half mirror 62. According to the HMD 60 configured in this way, by blocking the light from the outside world, the wearer 63 can observe only the image formed by the scanning light.

[0182] As described above, by applying the movable device 13 of the embodiment to the head-mounted display, it is possible to suppress a decrease in the resonance frequency that occurs when increasing the size of the movable part, and to provide a head-mounted display capable of performing optical scanning with high precision.

[0183] Such an HMD 60 includes the movable device 13, so that it is possible to suppress a decrease in the resonance frequency that occurs when increasing the size of the movable part, and to perform optical scanning with high precision. According to the HMD 60 including the movable device 13, it is possible to improve the resolution of the light trajectory near the center O of the viewing angle.

[0184] [Device for detecting the tilting position of the eyeball (device 80 for detecting the position of the pupil or cornea)] Next, an apparatus for detecting the tilting position of the eyeball including the movable device 13 will be described. The apparatus for detecting the tilting position of the eyeball is a device 80 for detecting the position of the pupil or cornea that detects the position of the pupil or cornea. FIG. 40 is a schematic configuration diagram showing an example of the device 80 for detecting the position of the pupil or cornea.

[0185] In the present embodiment, the "tilting position of the eyeball" is the position of the pupil or cornea of the eyeball, or the direction of the user's line of sight. Hereinafter, the "tilting position of the eyeball" will be described as the position of the pupil or cornea, and the "apparatus for detecting the tilting position of the eyeball" will be described as the "apparatus for detecting the position of the pupil or cornea". In addition, the apparatus for detecting the position of the pupil or cornea described below is synonymous with a line-of-sight direction tracking device (eye tracking device) that continuously detects or tracks the direction of the user's line of sight with or without a time interval.

[0186] The device 80 for detecting the position of the pupil or cornea shown in FIG. 40 includes a light source 82, a first light deflection unit 83, a movable device 13, a second light deflection unit 85, and a light receiving unit 86.

[0187] The light source 82 includes, for example, laser light sources 82r, 82g, 82b that emit red, green, and blue laser light, and an infrared laser light source 82ir that emits infrared laser light. The laser light sources 82r, 82g, 82b may be any one or a combination of two of them. The laser light sources 82r, 82g, 82b emit light for drawing an image by the movable device 13.

[0188] The infrared laser light source 82ir emits light for detecting the position of the pupil or the cornea. Note that the light for detecting the position of the pupil or the cornea is not limited to infrared light and may be visible light. From the viewpoint of improving the visibility of the drawn image, invisible light is preferable for the light for detecting the position of the pupil or the cornea.

[0189] The first light deflector 83 is, for example, a dichroic mirror, and deflects the light emitted from the light source 82 toward the reflecting surface 14 of the movable device 13 while combining the light. The pupil or corneal position detector 80 may include a plurality of first light deflectors 83-1, 83-2, 83-3, 83-4, 83-5 according to the number of the laser light sources 82r, 82g, 82b and the infrared laser light source 82ir. The first light deflector 83 includes the plurality of first light deflectors 83-1, 83-2, 83-3, 83-4, 83-5. The plurality of first light deflectors 83-1, 83-2, 83-3, 83-4, 83-5 deflect the respective lights while combining them.

[0190] The movable device 13 includes a reflecting surface 14, and scans the light deflected by the first light deflector 83 in a two-dimensional direction toward the second light deflector 85. At this time, the movable device 13 scans the light deflected by the first light deflector 83 by, for example, raster scanning to form an image. The movable device 13 can scan the light deflected by the first light deflector 83 by spiral scanning (spiral scan).

[0191] The second light deflector 85 is, for example, a holographic optical element that deflects the light L1 scanned by the movable device 13 toward the user's eyeball 87. At least a part of the light L2 deflected by the second light deflector 85 enters the user's eyeball 87 as display image light. Also, the second light deflector 85 may include a plurality of light deflecting members. For example, a configuration may be adopted in which a plurality of types of light deflecting members that reflect specific light among the light emitted from the light source 82 are used, and the reflecting surfaces are different for each light emitted from the light source 82. As a specific example, in the order closer to the eyeball 87, a configuration in which light deflecting members that reflect the light emitted by the laser light sources 82r, 82g, and 82b and a light deflecting member that reflects the light emitted from the infrared laser light source 82ir are laminated may be mentioned.

[0192] The light receiving unit 86 receives the light L3 reflected by the user's eyeball 87 from among the light L2 deflected by the second light deflector 85, and outputs a detection signal SD corresponding to the received light. The light receiving unit 86 is, for example, an image sensor capable of detecting infrared rays. Also, a plurality of light receiving units 86 may be provided at positions capable of receiving the light L3 reflected by the user's eyeball 87. The light received by the light receiving unit 86 changes in light intensity depending on the position change of the eyeball (pupil, cornea, etc.), that is, the change in the line-of-sight direction. Therefore, the pupil or cornea position detection device 80 in the present embodiment detects or estimates the pupil or cornea position based on the intensity of the light received by the light receiving unit 86. Also, the light receiving unit 86 may be configured to image the eyeball 87 irradiated with the light L2 deflected by the second light deflector 85. In this case, the pupil or cornea position detection device 80 detects or estimates the tilt position of the eyeball based on the position of the pupil or cornea included in the captured image (detection signal SD) and the position where the light L2 deflected by the second light deflector 85 is reflected in the eyeball 87.

[0193] As described above, the pupil or corneal position detection device 80 according to the present embodiment can detect the position of the pupil or the cornea while forming an image with the movable device 13. Further, since the movable device 13 is configured to be able to scan light more efficiently, image formation and detection of the position of the pupil or the cornea can be realized with lower power. Furthermore, the movable device 13 can obtain the above-described effects without changing the area required for mounting on the pupil or corneal position detection device 80 compared to the configuration of the prior art. Thereby, the pupil or corneal position detection device 80 can be configured not to increase in size.

[0194] In addition, the pupil or corneal position detection device 80 can be mounted on a head-mounted display as, for example, a gaze direction tracking (eye tracking) device to detect or track the gaze direction of the user. In this case, for example, by reducing the resolution of the image displayed in other regions with respect to the image displayed in the region near the gaze direction of the user (foveal rendering), the image processing can be speeded up compared to the case of displaying a high-resolution image over the entire area.

[0195] FIG. 41 is a schematic configuration diagram showing an example of the pupil or corneal position detection device 80. As shown in FIG. 41, the pupil or corneal position detection device 80 includes a light source 82, first light deflecting units 83-1 to 83-4, a lens 92, a lens 93, a scanning mirror 94, a deflecting mirror 95, a second light deflecting unit 85, a light receiving unit 86, and a control unit 96.

[0196] The lens 92 is an optical system that converts the light emitted by the light source 82 into substantially parallel light. The lens 93 is an optical system that shapes the light converted into substantially parallel light by the lens 92 into a desired laser beam state. In the present embodiment, a configuration having the lens 92 and the lens 93 is shown, but the lens 92 and the lens 93 are not necessarily provided.

[0197] The light formed by lenses 92 and 93 is incident on the scanning mirror 94 (the movable device 13). The scanning mirror 94 scans the incident light to form image light. The formed image light is incident on the deflection mirror 95 and is reflected in the direction toward the second light deflection unit 85. The deflection mirror 95 corresponds to the first light deflection unit 83-5 described with reference to FIG. 34, and preferably has a configuration capable of scanning the light provided with the movable device 13. By configuring the deflection mirror 95 to be capable of light scanning, an image can be projected over a wider range.

[0198] In the above description, the configuration in which the deflection mirror 95 is disposed between the scanning mirror 94 and the second light deflection unit 85 is illustrated. However, the pupil or corneal position detection device 80 is not limited thereto. In the pupil or corneal position detection device 80, the scanning mirror 94 may be disposed between the deflection mirror 95 and the second light deflection unit 85, and the light reflected by the deflection mirror 95 may be scanned in two axial directions by the scanning mirror 94 and incident on the second light deflection unit 85.

[0199] The control unit 96 detects the position of the user's pupil or cornea based on the detection signal SD output by the light receiving unit 86 and obtains information indicating the line-of-sight direction. Further, the control unit 96 gives a formation drive signal SL1 to the light source 82 to control the light emission and light intensity of the light source 82, and gives a scanning drive signal SS to the scanning mirror 94 to drive the scanning mirror 94 in order to form an image projected on the retina 32. When the deflection mirror 95 has a configuration capable of light scanning, the control unit 96 gives a deflection drive signal ST to the deflection mirror 95 to drive the deflection mirror 95 in order to control the projection position of the image according to the acquired line-of-sight information.

[0200] As described above, examples of the embodiments of the present invention have been described. However, the present invention is not limited to such specific embodiments, and various modifications and changes are possible within the scope of the gist of the present invention described in the claims.

[0201] In the above-described embodiments, a configuration in which a reflecting surface is provided on the movable part has been illustrated. However, the present invention is not limited to this, and the movable part may include other optical elements such as a diffraction grating, a photodiode, a heater (for example, a heater using SiN), a light source (for example, a surface-emitting laser), or may include both a reflecting surface and other optical elements.

[0202] [Processing circuit] Each function of the above-described embodiments can be realized by one or a plurality of processing circuits. Here, the "processing circuit" in this specification means a processor programmed to execute each function by software like a processor implemented by an electronic circuit, an ASIC (Application Specific Integrated Circuit) designed to execute each function described above, a DSP (digital signal processor), an FPGA (field programmable gate array), or a device such as a conventional circuit module.

[0203] One aspect of the present invention may be as follows. <1> A movable part, A driving part for driving the movable part, A control part for applying a driving voltage to the driving part, and The driving voltage is A first waveform in which the amplitude continuously increases in a first period, A second waveform in which the amplitude continuously decreases in a second period after the first period, In a third period after the second period, a movable device including a basic period waveform including a third waveform having a waveform in which the amplitude continuously increases and a waveform in which the amplitude continuously decreases, which are shorter than the sum of the first period and the second period. <2> The movable device according to <1> above, wherein the third waveform is in antiphase with the first waveform. <3> The basic period waveform is During the second period and the third period, or in a fourth period after the third period, it includes a fourth waveform whose amplitude is a predetermined value. The movable device according to <1> or <2> above, wherein the predetermined value is equal to or less than the value of the smallest amplitude among the second waveform or the third waveform immediately before the fourth period. <4> The movable device according to <3> above, wherein the fourth period is in at least one of between the second period and the third period, or after the third period. <5> The movable device according to <3> or <4> above, wherein the fourth waveform is a DC waveform. <6> The drive unit includes a detection piezoelectric element that generates a detection signal based on the movement of the movable unit. The control unit determines the drive waveform of the third waveform based on information regarding the swing of the movable unit obtained from the detection signal, and the movable device according to any one of <1> to <5> above. <7> The drive unit includes a first drive unit that swings the movable unit around a first axis, and a second drive unit that swings the movable unit around a second axis intersecting the first axis. When the frequency of the basic periodic waveform is ffps, the frequency of the high-speed signal periodic waveform constituting the basic periodic waveform is fs, the first resonance frequency at which the movable unit swings around the first axis is f1, the second resonance frequency at which the movable unit swings around the second axis is f2, and an arbitrary natural number is N, The movable device according to <6> above, wherein ffps is a value such that fs + Nffps and fs - Nffps do not coincide with f1 and f2. <8> The movable device according to <7> above, wherein the first resonance frequency f1 and the second resonance frequency f2 are the same value. <9> A projection device having an optical scanning system including the movable device according to any one of <1> to <8> above. <10> A moving body including the projection device according to <9> above. <11> A head-mounted display including the movable device according to any one of <1> to <9> above. <12> A head-up display including the movable device according to any one of <1> to <9> above. <13> A laser headlamp including the movable device according to any one of <1> to <9> above. <14> An object recognition device including the movable device according to any one of <1> to <9> above. <15> A pupil or corneal position detection device including the movable device according to any one of <1> to <9> above. <16> A movable method of driving a movable part by applying a drive voltage from a control part to a drive part for driving the movable part, wherein the drive voltage includes a first waveform whose amplitude continuously increases in a first period, a second waveform whose amplitude continuously decreases in a second period after the first period, and a third waveform having a waveform whose amplitude continuously increases and a waveform whose amplitude continuously decreases, which are shorter than the sum of the first period and the second period, in a third period after the second period, and the movable method is characterized by including a basic period waveform. <17> The drive part includes a detection piezoelectric element that generates a detection signal based on the drive of the drive part, and the control part determines the drive waveform of the third waveform based on information regarding the swing of the movable part acquired from the detection signal. The movable method according to <16> above.

Description of Reference Numerals

[0204] 10 Optical Scanning System 11 Control Device 13 Movable Device 14 Reflective Surface 30 Control Part 50 Laser Headlamp 60 Head-Mounted Display 101 Mirror Unit (Movable Unit) 110a, 110b, 110c, 110d First Driving Unit (Driving Unit) 130a, 130b Second Driving Unit 400 Automobile (Moving Body) 500 Head-Up Display Device (Projection Device) 700 Laser Radar Device (Object Recognition Device) Ta First Period Tb Second Period Tc Fourth Period Td Fourth Period Te Period Tf Period Tg Fourth Period Th Third Period

Prior Art Documents

Patent Documents

[0205]

Patent Document 1

Claims

1. A movable part; A drive unit that drives the movable unit; A control unit that applies a drive voltage to the drive unit, The driving voltage is a first waveform whose amplitude increases continuously during a first period; a second waveform whose amplitude continuously decreases in a second period subsequent to the first period; a third waveform having a waveform whose amplitude continuously increases and a waveform whose amplitude continuously decreases in a third period that is shorter than the sum of the first period and the second period; A movable device including a fundamental periodic waveform including:

2. 2. The movable device of claim 1, wherein the third waveform is in antiphase with the first waveform.

3. The fundamental period waveform is a fourth waveform having an amplitude of a predetermined value in a fourth period between the second period and the third period or after the third period, The movable device according to claim 1 , wherein the predetermined value is equal to or smaller than the smallest amplitude value of the second waveform or the third waveform immediately before the fourth period.

4. The movable device of claim 3 , wherein the fourth period of time is at least one of between the second period of time and the third period of time and after the third period of time.

5. 4. The movable device of claim 3, wherein the fourth waveform is a DC waveform.

6. the driving unit includes a detection piezoelectric element that generates a detection signal based on the movement of the movable part, The movable device according to claim 1 , wherein the control unit determines the drive waveform of the third waveform based on information regarding the oscillation of the movable part obtained from the detection signal.

7. The drive unit is A first drive unit that swings the movable unit around a first axis; a second drive unit that swings the movable unit around a second axis that intersects with the first axis, When the frequency of the fundamental periodic waveform is ffps, the frequency of the high-speed signal periodic waveform constituting the fundamental periodic waveform is fs, a first resonance frequency that causes the movable part to oscillate around the first axis is f1, a second resonance frequency that causes the movable part to oscillate around the second axis is f2, and N is an arbitrary natural number, 7. The movable device according to claim 6, wherein ffps is a value such that fs+Nffps and fs-Nffps are not equal to f1 and f2.

8. The movable device according to claim 7 , wherein the first resonance frequency f1 and the second resonance frequency f2 have the same value.

9. A projection device having an optical scanning system comprising a movable device according to any one of claims 1 to 4.

10. A moving object comprising the projection device according to claim 9.

11. A head mounted display comprising the movable device according to any one of claims 1 to 4.

12. A head-up display comprising the movable device according to any one of claims 1 to 4.

13. A laser headlamp comprising a movable device according to any one of claims 1 to 4.

14. An object recognition device comprising the movable device according to any one of claims 1 to 4.

15. A pupil or cornea position detection device comprising the movable device according to any one of claims 1 to 4.

16. A method for moving a movable part by a control unit applying a drive voltage to a drive unit that drives the movable part, the method comprising: The driving voltage is a first waveform whose amplitude increases continuously during a first period; a second waveform whose amplitude continuously decreases in a second period subsequent to the first period; and a third waveform in a third period that is shorter than the sum of the first period and the second period and that has a waveform whose amplitude continuously increases and a waveform whose amplitude continuously decreases, the third waveform being shorter than the sum of the first period and the second period and that is subsequent to the second period.

17. the driving unit includes a detection piezoelectric element that generates a detection signal based on driving of the driving unit, The moving method according to claim 16 , wherein the control unit determines the drive waveform of the third waveform based on information about the oscillation of the movable part acquired from the detection signal.

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