JP5853929B2 - Optical scanning device and warning display system - Google Patents

Description

  The present invention relates to an optical scanning device that scans a light beam, and a warning display system to which the device is applied.

In recent years, various optical scanning devices using MEMS (Micro Electro Mechanical System) technology have been proposed for the purpose of downsizing the optical scanning device.
On the other hand, the applicant of the present application intervenes a diaphragm having a scanning mirror that reflects a light beam, a pair of torsional vibrators arranged on the same straight line passing through the center of gravity of the diaphragm, and a torsional vibrator. In addition, a resonance type optical scanning device that includes a support portion that supports the diaphragm and that can bring the diaphragm into a resonance state by applying a specific periodic excitation force has been proposed.

  Such a resonant optical scanning device can be applied in various fields. When applied to the vehicle field, for example, it is used for irradiation of radar light for detecting obstacles around the vehicle. It is also used to irradiate video light for displaying an image on the windshield.

  For example, in such a vehicle field, there is a need to improve the response when the irradiation range of radar light is narrowed or the size of a display image is reduced. In order to realize this, in the optical scanning device, when the amplitude of the diaphragm in the resonance state is reduced, it is necessary to shorten the time until the amplitude reaches the target value (hereinafter referred to as “amplitude reduction time”). .

  Here, Patent Document 1 discloses a mirror displacement angle in a forced displacement type optical scanning device in which a voltage applied to a driving device used for rotationally driving a diaphragm and a scanning mirror angle (mirror angle) correspond one-to-one. By reducing the applied voltage in accordance with a drive waveform obtained by a predetermined relational expression having parameters such as moment of inertia, damping force, spring constant, and electric capacity, a mirror angle A to a target angle B (where A <B) A technique for shortening the time to reach is disclosed.

JP 2009-265608 A

  However, even if the technique described in Patent Document 1 is adopted in the resonance type optical scanning device, the energy consumed by the damping force is small in the diaphragm that is already in the resonance state, and is supplied to compensate for this consumption. When the voltage is reduced, there is a problem that it is difficult to suppress the transient vibration until the amplitude of the diaphragm reaches the target value.

  That is, in the resonance type optical scanning device, even if the technique of the forced displacement type optical scanning device described in Patent Document 1 is adopted, it is difficult to suppress the transient vibration, and therefore it is difficult to shorten the amplitude reduction time. There was a problem of being.

  The present invention has been made in view of the above problems, and it is an object of the present invention to provide a technique for suitably reducing the amplitude reduction time when the amplitude of the diaphragm in the resonance state is reduced in the resonance type optical scanning device. And

  The present invention made to achieve the above object is a so-called resonance type optical scanning device, which is arranged on the same straight line passing through the center of gravity of the diaphragm and the diaphragm having a scanning mirror for reflecting the light beam. A pair of torsional vibration parts that vibrate torsion, a support part that supports the diaphragm via the torsional vibration part, and an excitation force that is set in advance to resonate the diaphragm about the pair of torsional vibration plates as a rotation axis First driving means for generating.

  In such a configuration, in the present invention, the distance between the movable portion having the facing surface facing the side surface of the diaphragm and the facing surface and the side surface of the diaphragm is defined as a gap distance, and at least in the direction in which the gap distance changes. Second driving means for generating a preset acting force for displacing a part of the movable portion including the opposing surface.

  In the optical scanning device of the present invention, when the control means controls the first driving means and the second driving means, the amplitude in the resonance state of the diaphragm is maintained at the target value, the above-mentioned according to the target value. When the excitation force is set and the time until the amplitude reaches the target value when the amplitude is reduced (that is, the amplitude reduction time) is shortened, the above-described action force is set so that the gap distance is reduced. It was configured as follows.

  In such a configuration, in the resonance state of the diaphragm, the kinetic energy and elastic energy of the diaphragm are supplied by applying the excitation force via the first driving means, and the energy consumed by the damping force is balanced. This keeps the energy in the vibration system constant.

  As described above, in a diaphragm that is already in a resonance state, the energy consumed by the damping force is small, and when the excitation force is reduced, transient vibration until the diaphragm amplitude reaches the target value is suppressed. Difficult to do.

  On the other hand, in the present invention, in the resonance state of the diaphragm, the gap distance between the movable part (opposite surface) and the diaphragm (side surface) is reduced by applying an acting force via the second driving means. Therefore, a configuration is adopted in which the air resistance received by the diaphragm is increased and the kinetic energy loss of the diaphragm due to the damping force is increased.

  According to such a configuration, energy in the vibration system can be quickly reduced, and transient vibration can be suppressed. Therefore, according to the present invention, in the resonance type optical scanning device, the amplitude reduction time can be suitably shortened when the amplitude of the diaphragm in the resonance state is reduced.

  The side surface of the diaphragm is preferably the surface having the largest distance from the rotation axis (hereinafter referred to as “rotation axis distance maximum surface”). That is, when the amplitude reduction time is shortened when the amplitude is reduced, it is desirable to adopt a configuration in which the gap distance between the surface of the movable part and the surface having the largest distance between the rotating shaft of the diaphragm is reduced.

  According to such a configuration, the rotation axis distance maximum surface in the diaphragm is the surface having the largest speed in the diaphragm (that is, the maximum speed surface), and the shear force of the air resistance received by the diaphragm is proportional to the speed. Since it is inversely proportional to the gap distance, the shear force received by the diaphragm can be maximized, and as a result, the air resistance received by the diaphragm can be further increased. Thereby, in the resonance type optical scanning device, when the amplitude of the diaphragm in the resonance state is reduced, the amplitude reduction time can be further shortened.

  Further, in the present invention, the material of the movable part is not particularly limited. For example, when the movable part is configured to have an elastic material, the second driving means uses the elastic deformation to make the above-mentioned opposing part. Part of the movable part including the surface can be displaced.

  Specifically, the movable portion has the opposed surface disposed in the central portion and both end portions fixed to the support portion, and a portion between the central portion and the both end portions is defined as an intermediate portion. And at least one of the two end portions is constituted by an elastic body, and the second drive means has an actuator mechanism for deforming the elastic body so that the central portion of the movable portion is displaced toward the side surface of the diaphragm. Good.

  In the present invention, the arrangement of the actuator mechanism is not particularly limited. For example, when the actuator mechanism is provided in a component such as a movable portion, a support portion, or a diaphragm, or provided between these components. This is advantageous in that it is not necessary to increase the size of the optical scanning device.

  In this case, for example, the actuator mechanism is provided on at least one of the movable side electrode portion provided in at least one of the intermediate portion and the central portion of the movable portion and the movable side electrode portion with a predetermined interval therebetween. The second driving means applies a voltage between the movable side electrode portion and the fixed side electrode portion, so that the movable side electrode portion and the fixed side electrode portion are used as the acting force. A configuration in which electrostatic attraction is generated between the two may be employed.

  In such a configuration, when a voltage is applied to the actuator mechanism, the movable side electrode portion provided in at least one of the intermediate portion and the central portion of the movable portion, and the fixed side electrode provided in at least one of the support portion and the diaphragm The elastic body that forms at least one of the intermediate part and both ends of the movable part is deformed in the direction of the rotation axis of the diaphragm due to the electrostatic attractive force generated between the movable part and the central part (opposing surface) of the movable part. ) Can be suitably displaced toward the side surface of the diaphragm.

  In addition, the arrangement of the movable side electrode part and the fixed side electrode part is, for example, when the movable side electrode part is provided in the middle part of the movable part, the fixed side electrode part is fixed to the support part, and the movable side electrode part Is provided at the central portion of the movable portion, a mode in which the fixed electrode portion is provided on the side surface of the diaphragm can be employed.

  Further, for example, the actuator mechanism is a piezoelectric actuator that connects the intermediate part of the movable part and the support part, and the distortion of the actuator increases according to the applied voltage, and the second driving means applies a voltage to the piezoelectric actuator. By doing so, you may employ | adopt the structure which makes a piezoelectric actuator generate | occur | produce the tensile force with respect to the center part of the said movable part as said action force.

  In such a configuration, when a voltage is applied to the actuator mechanism, an elastic body that constitutes at least one of the intermediate portion and both end portions of the movable portion due to distortion generated in the piezoelectric actuator that connects the intermediate portion and the support portion of the movable portion. Therefore, the central portion (opposing surface) of the movable part can be suitably displaced toward the side surface of the diaphragm.

  Further, for example, the actuator mechanism is a thermal actuator that constitutes an intermediate portion of the movable portion as the elastic body described above, and is deformed toward the rotating shaft of the diaphragm in response to an increase in the environmental temperature, and the second drive means includes: A configuration may be employed in which the heater is heated to raise the environmental temperature, and the thermal actuator generates a propulsive force for the central portion of the movable portion as the acting force.

  In such a configuration, when the heater is heated in the vicinity of the actuator mechanism, the thermal actuator that constitutes the intermediate portion of the movable portion as an elastic body is deformed toward the rotation axis of the diaphragm, so that the central portion of the movable portion (opposing Surface) can be suitably displaced toward the side surface of the diaphragm. In addition, since the air resistance received by the diaphragm due to the temperature rise can be further increased, the amplitude reduction time can be further shortened when the amplitude of the diaphragm in the resonance state is reduced.

  By the way, in the present invention, when the side surface of the diaphragm and the opposing surface of the movable part are formed in a comb-tooth shape that meshes with each other at a predetermined interval, the air resistance received by the diaphragm by increasing the surface area facing each other. Therefore, when the amplitude of the diaphragm in the resonance state is reduced, the amplitude reduction time can be further shortened.

In addition, the optical scanning device demonstrated above can be suitably integrated, for example in the warning display system for vehicles.
Specifically, the warning display system of the present invention has an optical scanning device that is mounted on a vehicle and scans a light beam, and an image composed of video light emitted from the optical scanning device is displayed as a virtual image on a vehicle occupant. As a head-up display device that displays the image so as to be visually recognized, and an in-vehicle control device that performs image display control in the head-up display device.

  Among these, the in-vehicle control device outputs a reduction command for reducing the display image area when performing a warning display related to the traveling of the vehicle via the head-up display device. When a reduction command is input from the apparatus, the gap distance is reduced as described above.

  In the warning display system configured in this way, as described above, in the resonance type optical scanning device, when the amplitude in the resonance state of the diaphragm is reduced, the amplitude reduction time can be suitably shortened. When the display image area in the head-up display device is reduced, the responsiveness can be improved, and accordingly, when the warning display relating to the traveling of the vehicle is performed, the vehicle occupant can be alerted promptly.

  In addition, according to the warning display system of the present invention, the brightness of the display image is increased by reducing the display image area. It is possible to call attention in an easy-to-understand manner.

1 is a schematic diagram showing a basic configuration of an optical scanning device 10. FIG. 1 is a schematic diagram illustrating a characteristic configuration of an optical scanning device 10. FIG. 1 is a block diagram showing an electrical configuration of an optical scanning device 10 and a schematic configuration of a warning display system 1. FIG. 3 is an image diagram showing a schematic configuration of a head-up display device 2. FIG. It is explanatory drawing which shows the transient vibration in a vibration system. It is explanatory drawing which shows the pattern which reduces the amplitude of the diaphragm 11 by making small the supply energy (drive voltage) to a vibration system. (A) is explanatory drawing which shows the pattern which reduces the amplitude of the diaphragm 11 by enlarging the kinetic energy loss of a vibration system, (b) further reduces supply energy (drive voltage) to a vibration system. It is explanatory drawing which shows the pattern which reduces the amplitude of the diaphragm 11 by doing. 3 is a timing chart for explaining an operation at the time of warning display in the warning display system 1; It is the schematic which shows the structure of the actuator mechanism 31 in other embodiment. FIG. 6 is a schematic diagram illustrating configurations of a movable portion 15 and an actuator mechanism 31 in Modification Example 1. FIG. 10 is a schematic diagram for explaining an elastic body 15b in Modification 1; FIG. 10 is a first schematic diagram illustrating configurations of a movable portion 15 and an actuator mechanism 31 in Modification 2. FIG. 10 is a first schematic diagram for explaining an actuator mechanism 31 in Modification 2. FIG. 11 is a second schematic diagram for explaining an actuator mechanism 31 in Modification 2. FIG. 10 is a second schematic diagram illustrating configurations of a movable unit 15 and an actuator mechanism 31 in Modification 2.

Embodiments of the present invention will be described below with reference to the drawings.
<Basic configuration of optical scanning device>
First, the basic configuration of the optical scanning device 10 as an embodiment of the present invention will be described.

  Basically, the optical scanning device 10 includes a diaphragm 11 having a scanning mirror 10a that reflects a light beam, and a pair of torsional vibration units 12 that are arranged on the same straight line passing through the center of gravity JS of the diaphragm 11 and torsionally vibrate. And a support portion 13 that supports the diaphragm 11 with the torsional vibration portion 12 interposed therebetween.

  Specifically, as shown in FIG. 1, the optical scanning device 10 of the present embodiment constitutes a three-degree-of-freedom torsional vibrator, and as the diaphragm 11, a light reflecting portion 11 a, an inner gimbal 11 b, and an outer A gimbal 11c is provided. Further, as a pair of torsional vibration parts, a first torsion elastic member 12a that connects the light reflecting part 11a and the inner gimbal 11b, a second torsion elastic member 12b that connects the inner gimbal 11b and the outer gimbal 11c, and the outer gimbal 11c. And a third torsion elastic member 12c that connects the fixed end 13c of the optical scanning device 10 to each other.

  Further, in the optical scanning device 10 of the present embodiment, the fixed end 13a of the inner gimbal 11b supports the light reflecting portion 11a via the first twist elastic member 12a, and the fixed end 13b of the outer gimbal 11c is second twist elastic. The inner gimbal 11b is supported via the member 12b, and the fixed end 13c of the optical scanning device 10 is configured to support the outer gimbal 11c via the third twisted elastic member 12c. That is, the fixed end 13a of the inner gimbal 11b functions as a support portion 13 for the light reflecting portion 11a, the fixed end 13b of the outer gimbal 11c functions as a support portion 13 for the inner gimbal 11b, and the fixed end 13c of the optical scanning device 10 is It functions as a support portion 13 for the outer gimbal 11c.

  The light reflecting portion 11a includes a scanning mirror 10a and a mirror fixing frame 14. The scanning mirror 10a has a circular shape, and a mirror surface portion of an aluminum thin film is formed on the surface. The mirror fixing frame 14 has a rectangular shape such as a hexagonal shape on the outside and a circular shape on the inside, and fixes the scanning mirror 10a in the frame.

  Further, as described above, in the optical scanning device 10 of the present embodiment, the inner gimbal 11b supports the light reflecting portion 11a within the rectangular frame, and the outer gimbal 11c supports the inner gimbal 11b within the rectangular frame. Is. In FIG. 1, the inner gimbal 11b and the outer gimbal 11c are illustrated in a quadrangular shape, but may be other rectangular shapes such as a hexagonal shape.

  The first torsion elastic member 12a, the second torsion elastic member 12b, and the third torsion elastic member 12c are made of an elastically deformable material. Among these, the 1st twist elastic member 12a is arrange | positioned on the same straight line which passes through the gravity center JS of the light reflection part 11a, and becomes the rotating shaft h of the light reflection part 11a. Thereby, the light reflection part 11a is comprised so that a torsional vibration is possible centering | focusing on the rotating shaft h. The second torsion elastic member 12b is disposed on the same straight line passing through the center of gravity JS of the light reflecting portion 11a and the inner gimbal 11b, and becomes a rotation axis i orthogonal to the rotation axis h. Thus, the inner gimbal 11b is configured to be able to twist and vibrate about the rotation axis i. The third torsion elastic member 12c is arranged on the same straight line passing through the center of gravity JS of the light reflecting portion 11a, the inner gimbal 11b, and the outer gimbal 11c, and intersects with the rotation axis h and the rotation axis i at 45 °. This is the rotation axis j. As a result, the outer gimbal 11c is configured to be able to twist and vibrate about the rotation axis j.

Further, the optical scanning device 10 includes a first drive unit 20 for resonating the light reflecting unit 11a, the inner gimbal 11b, and the outer gimbal 11c with the rotation axes h, i, j as the center.
The first driving unit 20 applies a voltage to the so-called stepped electrostatic comb actuator 21 and the stepped electrostatic comb actuator 21 arranged in parallel to the rotation axis j along the left and right outer surfaces of the outer gimbal 11c. The first voltage applying unit 22 (see FIG. 3) to be applied is configured.

  The stepped electrostatic comb actuator 21 is formed in a comb-like shape that meshes with a movable comb tooth 21a formed on the left and right outer surfaces of the outer gimbal 11c with a certain distance from the movable comb tooth 21a. And a fixed comb tooth 21b arranged with a step, and when a voltage is applied, an electrostatic attractive force is generated between the movable comb tooth 21a and the fixed comb tooth 21b.

Here, the operation principle of the optical scanning device 10 of this embodiment will be briefly described. For details, refer to, for example, Japanese Patent Application Laid-Open No. 2008-129069.
As described above, the optical scanning device 10 of this embodiment is a three-degree-of-freedom twisted vibrator having a degree of freedom of twisting about the rotation axes h, i, and j.

  A three-degree-of-freedom torsional vibrator theoretically has three vibrators. That is, the three vibration modes have different resonance frequencies, and the ratio of the angular amplitude (hereinafter simply referred to as “amplitude”) of the torsional vibration of each frame to each resonance frequency is different (this is called a vibration mode).

  For example, the movable comb tooth 21a comes closest to the fixed comb tooth 21b twice while the outer gimbal 11c vibrates for one cycle. For this reason, if a periodic electrostatic attraction force close to twice the resonance frequency is applied, the three-degree-of-freedom torsional vibrator can be brought into a resonance state (hereinafter, the periodic electrostatic attraction force applied to make the resonance state is “periodically applied”). Called "vibration force"). Further, every time the movable comb teeth 21a approach the fixed comb teeth 21b, a periodic vibration force can be applied.

  If a periodic excitation force having a frequency corresponding to each of vibration mode A, vibration mode B, vibration mode C,... Different from each other is applied, each vibration mode can be excited. In addition, if a plurality of periodic excitation forces with a plurality of frequencies are superimposed and applied, a plurality of vibration modes can be excited simultaneously.

  For this reason, for example, the laser beam is reflected by the scanning mirror 10a of the light reflecting portion 11a, and the vibration mode A and the vibration mode B are simultaneously excited with the vibration mode A as the main scanning direction and the vibration mode B as the sub-scanning direction. Thus, the scanning mirror 10a can vibrate and scan the laser beam two-dimensionally.

  Specifically, when a driving voltage is applied to the stepped electrostatic comb actuator 21 and a periodic electrostatic attractive force is generated between the movable comb teeth 21a and the fixed comb teeth 21b, the third torsion elastic member 12c is elastic. By deforming and twisting, the outer gimbal 11c reciprocally vibrates about the third twisted elastic member 12c as the rotation axis j.

  Here, the first voltage application unit 22 (see FIG. 3) outputs a drive voltage signal having a frequency twice the resonance frequency of the vibration mode in which the amplitude of the light reflection unit 11a is larger than that of the inner gimbal 11b and the outer gimbal 11c. As a result, the vibration system composed of the diaphragm 11 and the torsional vibrator 12 resonates, and the diaphragm 11 reciprocates at the resonance frequency.

  When the outer gimbal 11c reciprocally vibrates, the second torsion elastic member 12b is elastically deformed and twisted by the power, so that the outer gimbal 11c and the inner gimbal 11b reciprocate with the second torsion elastic member 12b as the rotation axis i. As the first torsional elastic member 12a is elastically deformed and twisted, the inner gimbal 11b and the light reflecting portion 11a reciprocally vibrate about the first torsional elastic member 12a as the rotation axis h.

  In this state, when a light beam is irradiated onto the light reflecting portion 11a from a laser light source 3 (see FIG. 4), which will be described later, the light beam is emitted by being reflected by the mirror surface of the scanning mirror 10a, and light is emitted. Along with the reciprocating vibration of the reflecting portion 11a, scanning is performed in a direction corresponding to the rotation angle of the light reflecting portion 11a.

  On the other hand, with the reciprocating vibration of the outer gimbal 11c, the distance between the movable comb teeth 21a and the fixed comb teeth 21b also periodically changes. Thereby, the electrostatic capacitance between the movable comb teeth 21a and the fixed comb teeth 21b changes according to the rotation angle of the outer gimbal 11c. Based on these capacitances, the rotation angle of the outer gimbal 11c can be detected. Note that, in the resonance state of the three-degree-of-freedom torsional vibrator, the phase angle between the frames is theoretically 0 degree or 180 degrees. Therefore, by detecting the rotation angle of the outer gimbal 11c, The rotation angle can be detected. The optical scanning device 10 of the present embodiment includes the amplitude sensor 40 that detects the amplitude based on the rotation angle of the light reflecting portion 11a in this way.

<Characteristic configuration of optical scanning device>
Next, a characteristic configuration of the optical scanning device 10 of the present embodiment will be described.
In addition to the above basic configuration, the optical scanning device 10 of the present embodiment includes a movable portion 15 having a facing surface 15a facing the side surface 11d of the diaphragm 11, and a facing surface 15a of the movable portion 15 and the side surface of the diaphragm 11. And a second drive unit 30 that displaces at least a part of the movable unit 15 including the facing surface 15a in a direction in which the distance to the 11d (hereinafter referred to as “gap distance d”) changes.

  Specifically, as shown in FIGS. 2 (a) and 2 (b), the movable portion 15 of the present embodiment is parallel to the torsional vibration portion 12, the opposing surface 15a is disposed at the center portion, and both ends The portion is fixed to the support portion 13, and a portion (hereinafter referred to as "intermediate portion") between the central portion and both end portions is made of a material that can be elastically deformed. Hereinafter, the elastically deformable portion of the movable portion 15 is referred to as an elastic body 15b. In addition, the movable portion 15 is arranged on the same plane without a step with the diaphragm 11.

  Here, the diaphragm 11 refers to any of the light reflecting portion 11a, the inner gimbal 11b, and the outer gimbal 11c, and the support portion 13 refers to the inner portion when the diaphragm 11 refers to the light reflecting portion 11a. It means the fixed end 13a of the gimbal 11b. When the diaphragm 11 points to the inner gimbal 11b, it means the fixed end 13b of the outer gimbal 11c, and when the diaphragm 11 points to the outer gimbal 11c, the above-mentioned fixed end 13c. Means. The torsional vibration part 12 here means the first torsion elastic member 12a when the diaphragm 11 indicates the light reflecting part 11a, and the second torsion when the diaphragm 11 indicates the inner gimbal 11b. It means the elastic member 12b, and when the diaphragm 11 points to the outer gimbal 11c, it means the third twisted elastic member 12c. In the following, the rotation axis k means the rotation axis h when the diaphragm 11 points to the light reflecting portion 11a, and means the rotation axis i when the vibration plate 11 points to the inner gimbal 11b. When the diaphragm 11 points to the outer gimbal 11c, it means the rotation axis j.

  On the other hand, the second drive unit 30 includes an actuator mechanism 31 that deforms the elastic body 15b so that the central portion (that is, the facing surface 15a) of the movable portion 15 is displaced toward the side surface 11d of the diaphragm 11, and the actuator mechanism 31. The second voltage applying unit 32 (see FIG. 3) that generates a predetermined acting force.

  The actuator mechanism 31 of the present embodiment includes a movable side electrode portion 32a projecting toward the torsional vibration portion 12 at an intermediate portion of the movable portion 15, and a fixed interval between the movable side electrode portion 32a fixed to the support portion 13. The fixed-side electrode portion 32b disposed at a distance is constituted by a comb-shaped electrostatic actuator disposed on the same plane as the diaphragm 11, and when a voltage is applied, the movable-side electrode portion 32a and the fixed-side electrode An electrostatic attractive force is generated between the portion 32b. The movable side electrode portion 32a is connected to a portion that is substantially the center of the elastic body 15b, and the fixed side electrode portion 32b is disposed in parallel to the torsional vibration portion 12.

  The movable part 15 and the actuator mechanism 31 described above have a time (amplitude reduction time) until the amplitude reaches the target value when reducing the amplitude of the light reflecting part 11a in the resonance state of the three-degree-of-freedom torsional vibrator. In order to shorten it, it is provided for at least one diaphragm 11.

  More specifically, in the resonance state of the three-degree-of-freedom torsional vibrator, the energy consumed by the damping force of the diaphragm 11 is small, and this consumed amount is used as the driving voltage by the first voltage applying unit 22 (see FIG. 3). Since the amplitude of the light reflecting portion 11a is maintained at a predetermined constant value, it is difficult to suppress the transient vibration of the diaphragm 11 when only the drive voltage is reduced.

  In addition, as shown in FIG. 5, the transient vibration here means that the amplitude of the diaphragm 11 is reduced from a certain amplitude A to an amplitude B that is a target value (where A> B). It means that the amplitude does not immediately reach a value corresponding to the drive voltage, but gradually decreases over time.

  On the other hand, in the optical scanning device 10 of the present embodiment, in the resonance state of the three-degree-of-freedom torsional vibrator, by applying a certain acting force via the second drive unit 30, the movable unit 15 and the diaphragm 11 By reducing the gap distance d, the air resistance received by the diaphragm 11 is increased, thereby increasing the kinetic energy loss of the diaphragm 11.

  Specifically, the second voltage application unit 32 (see FIG. 3) of the present embodiment does not apply a drive voltage to the actuator mechanism 31 during normal driving. Thereby, as shown in FIG. 2A, since the electrostatic attractive force does not act between the movable side electrode portion 32a and the fixed side electrode portion 32b, the elastic body 15b becomes parallel to the torsional vibration portion 12. Therefore, the gap distance d is maintained at the default distance.

  On the other hand, a drive voltage is applied to the actuator mechanism 31 during excessive vibration. Accordingly, as shown in FIG. 2B, the movable electrode portion 32a is displaced toward the fixed electrode portion 32b by the electrostatic attractive force generated between the movable electrode portion 32a and the fixed electrode portion 32b. When the elastic body 15b is deformed in the direction of the rotation axis k while being pulled by this, the central portion (that is, the facing surface 15a) of the movable portion 15 is displaced toward the side surface 11d of the diaphragm 11, and the gap distance d becomes smaller.

  Here, the side surface 11d of the diaphragm 11 refers to a surface having the longest distance from the rotation axis formed by the torsional vibration unit 12 (hereinafter referred to as “rotation axis distance maximum surface”). In other words, the rotation axis distance maximum surface is the surface having the largest speed in the diaphragm 11, and the shearing force of the air resistance received by the diaphragm 11 is proportional to the speed and inversely proportional to the gap distance d. Can effectively increase the shearing force applied to.

  Therefore, by reducing the gap distance d, it is possible to increase the shearing force that the diaphragm 11 receives, that is, the air resistance that the diaphragm 11 receives, and hence the kinetic energy loss of the diaphragm 11. And by increasing the kinetic energy loss of the diaphragm 11, the transient vibration of the diaphragm 11 can be suppressed, and the amplitude reduction time can be shortened. Please refer to R. Byron Bird et al. “TRANSPORT PHENOMENA” (WILEY INTERNATIONAL EDITION) P3-5 for the relational expression of shear force.

<Electrical configuration of optical scanning device>
Next, the electrical configuration of the optical scanning device 10 of the present embodiment will be described.
As shown in FIG. 3, the optical scanning device 10 of the present embodiment includes a diaphragm that is input from the amplitude sensor 40 in addition to the first voltage application unit 22, the amplitude sensor 40, and the second voltage application unit 32 described above. 11, an amplitude control circuit 50 that outputs a first drive command signal for controlling the first voltage application unit 22 based on information indicating the amplitude of 11 (amplitude information), and a damping force adjustment start command from the amplitude control circuit 50 And a damping force adjustment circuit 60 that outputs a second drive command signal for controlling the second voltage application unit 32 based on amplitude information from the amplitude sensor 40.

  Among these, the amplitude control circuit 50 excites the torsional vibrator having three degrees of freedom as described above, or energy consumed by the damping force of the diaphragm 11 in the resonance state (hereinafter also referred to as “consumption energy of the vibration system”). Is applied to the stepped electrostatic comb actuator 21 to set a periodic excitation force for maintaining the amplitude of the diaphragm 11 at a target value, and this set periodic vibration is set. A first drive command signal including information indicating the excitation force is output to the first voltage application unit 22.

  In addition, when an amplitude reduction command is input from the control circuit 70 of the HUD device 2 described later, the amplitude control circuit 50 reduces the drive voltage corresponding to the target value of amplitude as shown in FIG. 6 (in other words, The first drive command signal for reducing the amplitude of the diaphragm 11 is reduced by reducing the energy supplied to the vibration system), and a damping force adjustment start command is sent to the amplitude control circuit 50. It is designed to output. For details on the relationship between the amplitude of the vibration system in the resonance state, the energy consumed by the vibration system, and the energy supplied to the vibration system, see, for example, Hideo Saito, “Industrial Fundamental Vibration” Yokendo, P55-57. I want to be.

  On the other hand, when the damping force adjustment circuit 60 receives the damping force adjustment start command from the amplitude control circuit 50, the damping force adjustment circuit 60 sets the electrostatic attractive force for reducing the amplitude of the diaphragm 11 by applying a drive voltage to the actuator mechanism 31. Then, a second drive command signal including information indicating the set electrostatic attraction is output to the second voltage application unit 32. As a result, the gap distance d between the movable portion 15 and the diaphragm 11 is reduced, and the air resistance received by the diaphragm 11 is increased, thereby increasing the kinetic energy loss of the vibration system.

  That is, the damping force adjustment circuit 60 increases the kinetic energy loss of the vibration system, thereby increasing a curve (consumption energy curve) indicating the correlation between the energy consumption and amplitude of the vibration system as shown in FIG. By temporarily increasing the inclination, the damping force is adjusted so that the amplitude of the diaphragm 11 reaches the target value earlier.

  In order to further shorten the amplitude reduction time in this way, the amplitude X indicating the intersection of the curve (supply energy curve) indicating the correlation between the energy supplied to the vibration system and the amplitude (supply energy curve) and the consumption energy curve is temporarily set. It is advantageous to make it smaller.

  Therefore, the amplitude control circuit 50 applies the drive voltage smaller than the drive voltage corresponding to the target value of the amplitude to the stepped electrostatic comb actuator 21 to supply energy as shown in FIG. 7B. By temporarily reducing the slope of the curve, the damping force can be adjusted so that the amplitude of the diaphragm 11 reaches the target value more quickly.

<Schematic configuration of head-up display device>
Next, a schematic configuration of a head-up display device (hereinafter referred to as “HUD device”) 2 on which the optical scanning device 10 of the present embodiment is mounted will be described. Note that the HUD device 2 of the present embodiment is installed in a passenger compartment and causes an image of the image light scanned by the optical scanning device 10 to be visually recognized by a vehicle occupant as a virtual image. Specifically, the occupant visually recognizes that the virtual image exists at the position of the display image 3a in the foreground of the vehicle.

  As shown in FIG. 4A, the HUD device 2 is a known laser light source 3 used in a scanning image display device, and an optical scanning device that scans laser light (image light) emitted from the laser light source 3. 10 and a far-expanding optical system 4 composed of a lens or the like that magnifies and reflects a screen image composed of video light emitted from the optical scanning device 10. The image light emitted from the far-expanding optical system 4 is reflected by the windshield 5 and reaches the eye range 6 of the vehicle occupant. As a result, the occupant visually recognizes that the virtual image of the image light exists at the position of the display image 3a on the opposite side of the occupant with the windshield 5 interposed therebetween.

  As shown in FIG. 3, the HUD device 2 according to the present embodiment is connected to an electronic control device (hereinafter referred to as “ECU”) 7 in an in-vehicle network system built in a vehicle, and various types are sent from the ECU 7. An image is displayed based on information and various commands. Note that the ECU 7 of this embodiment determines that the vehicle is dangerous to some extent in advance so that the vehicle does not collide with the target based on a distance (for example, an inter-vehicle distance) with a target located around the vehicle as described later. In this case, a part of the image display control in the HUD device 2 is performed by transmitting warning information related to the traveling of the vehicle and an image reduction command for reducing the display image area. In other words, since the brightness of the display image is increased by reducing the display image area, as shown in FIG. 4B, the display image area is reduced compared to the normal display when the warning is displayed. It is possible to call attention in a manner that is easy for the vehicle occupant to understand.

<Configuration of warning display system>
Next, the configuration of the warning display system 1 to which the HUD device 2 of the present embodiment is applied will be described.
As shown in FIG. 3, the warning display system 1 of the present embodiment is installed near the center of the front end of the vehicle, radiates radar waves (laser light, radio waves, ultrasonic waves, etc.), and receives the reflected waves. A target exploration device 8 that detects a target existing in a preset exploration area (and thus an irradiation range), an ECU 7 in the in-vehicle network system, and a HUD device 2 installed in the vehicle interior. Is done.

  The target searcher 8 detects a target existing in a search area around the vehicle at every preset search cycle (radar wave irradiation cycle). Target information including at least the detected exploration area, “distance to the target”, and “relative speed with respect to the target” is generated and supplied to the ECU 7.

  For example, the target probe 8 is configured to include a light source that generates laser light to be a radar wave, a light receiving unit that receives the laser light, and a scanning unit that scans the laser light emitted from the light source. The distance to the target can be measured based on the round-trip time of the radar wave until the radar wave irradiated through the scanning unit is reflected by the target and reaches the light receiving unit.

  The ECU 7 is composed of one or a plurality of electronic control units. For normal display, the ECU 7 displays, for example, an image relating to the traveling of the vehicle such as a sign for guiding the vehicle to the destination, timing of turning left and right, and vehicle speed. Various information is transmitted to the HUD device 2.

  In addition, when the ECU 7 determines that the distance to the target (for example, the inter-vehicle distance) is less than a preset threshold distance based on the target information input from the target searcher 8, be careful of the vehicle occupant. An image reduction command for reducing the display image area is transmitted to the HUD device 2 as shown in FIG. For example, when it is determined that the inter-vehicle distance again exceeds the threshold distance, the image display based on the warning information is canceled, and a cancel command for returning the display image area to the normal size is transmitted to the HUD device 2. It is configured.

  As described above, the HUD device 2 includes the control circuit 70 that displays an image based on various information and various commands sent from the ECU 7. Further, when receiving an image reduction command from the ECU 7, the control circuit 70 outputs an amplitude reduction command to the amplitude control circuit 50 of the optical scanning device 10, and when receiving a release command from the ECU 7, the amplitude control circuit of the optical scanning device 10. 50 outputs a normal drive command.

  Accordingly, in the HUD device 2, when the amplitude control circuit 50 receives an amplitude reduction command from the control circuit 70 (in other words, an image reduction command from the ECU 7), as shown in FIG. Until a drive command (in other words, a release command from the ECU 7) is input, the drive voltage is set to be small, and the damping force adjusting circuit 60 generates a damping force by applying the driving voltage. As a result, when the warning is displayed by the HUD device 2, the amplitude of the diaphragm 11 decreases more quickly and reaches the target value. Thereafter, by receiving a release command from the ECU 7, the amplitude of the diaphragm 11 gradually returns to a value corresponding to a predetermined vibration mode.

<Effect>
As described above, in the warning display system 1 of the present embodiment, when the amplitude of the diaphragm 11 in the resonance state is reduced in the resonance type optical scanning device 10, the amplitude reduction time can be suitably shortened. Therefore, the responsiveness at the time of reducing the display image area in the HUD device 2 can be improved, and thus, when the warning display relating to the traveling of the vehicle is performed, the vehicle occupant can be alerted promptly. Further, according to such a warning display system 1, the brightness of the display image is increased by reducing the display image area. Therefore, when a warning display related to the traveling of the vehicle is performed, a change in the brightness causes a vehicle occupant. It is possible to call attention in an easily understandable manner.

  Further, in the diaphragm 11 already in a resonance state, the energy consumed by the damping force is small, and when the drive voltage supplied to compensate for this consumption is reduced, the amplitude of the diaphragm 11 reaches the target value. It is difficult to suppress the transient vibration up to. On the other hand, in the optical scanning device 10 of the present embodiment, the movable portion 15 (opposing surface 15a) and the diaphragm are applied by applying an electrostatic attractive force via the second drive unit 30 in the resonance state of the diaphragm 11. 11 (side surface 11d), the air resistance received by the diaphragm 11 is increased by reducing the gap distance d, thereby increasing the kinetic energy loss of the diaphragm 11. Therefore, energy in the vibration system can be quickly reduced, and transient vibration can be suppressed. Therefore, in the resonance type optical scanning device 10, when the amplitude of the diaphragm 11 in the resonance state is reduced, the amplitude reduction time can be suitably shortened.

  Further, in the optical scanning device 10, the side surface 11 d of the vibration plate 11 is disposed so as to face the facing surface 15 a of the movable portion 15 on the surface having the largest distance from the rotation axis (the rotation axis distance maximum surface). In other words, the rotation axis distance maximum surface in the diaphragm 11 is the surface having the largest speed in the diaphragm 11 (maximum speed surface), and the shearing force of the air resistance received by the diaphragm 11 is proportional to the gap distance d. Therefore, the shearing force applied to the diaphragm 11 can be effectively increased. As a result, the air resistance received by the diaphragm 11 is further increased, and in the resonant optical scanning device 10, when the amplitude of the diaphragm 11 in the resonance state is decreased, the amplitude reduction time can be further shortened. it can.

  Further, in the optical scanning device 10, the movable portion 15 has the opposed surface 15a disposed in the center portion, both end portions are fixed to the support portion 13, and the intermediate portion is constituted by the elastic body 15b. The second drive unit 30 includes an actuator mechanism 31 that deforms the elastic body 15 b so that the central portion of the movable unit 15 is displaced toward the side surface 11 d of the diaphragm 11.

  Specifically, the actuator mechanism 31 includes a movable side electrode portion 32a provided at an intermediate portion of the movable portion 15, and a fixed side electrode portion 32b provided on the support portion 13 with a predetermined interval from the movable side electrode portion 32a. Electrostatic attractive force is generated by applying a voltage between them, thereby causing the intermediate part (elastic body 15b) of the movable part 15 to deform in the direction of the rotation axis k of the diaphragm 11, The central portion (opposing surface 15 a) of the movable portion 15 can be suitably displaced toward the side surface 11 d of the diaphragm 11.

<Other embodiments>
As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment, In the range which does not deviate from the summary of this invention, it is possible to implement in various aspects.

  For example, in the actuator mechanism 31 of the above embodiment, the movable side electrode portion 32a is provided in the intermediate portion of the movable portion 15, and the fixed side electrode portion 32b is provided in the support portion 13. However, the present invention is not limited to this. Instead, as shown in FIG. 9, for example, the movable side electrode portion 32 a may be provided in the central portion of the movable portion 15, and the fixed side electrode portion 32 b may be provided on the side surface 11 d of the diaphragm 11.

  In this case, as shown in FIG. 9, the side surface 11 d of the diaphragm 11 and the opposing surface 15 a of the movable portion 15 are formed in a comb-teeth shape that meshes with each other at a predetermined interval. That is, since the shear force of the air resistance received by the diaphragm 11 is proportional to the surface area, the shear force received by the diaphragm 11 can be increased more effectively. As a result, the air resistance received by the diaphragm 11 is further increased, and in the resonant optical scanning device 10, when the amplitude of the diaphragm 11 in the resonance state is decreased, the amplitude reduction time can be further shortened. It becomes possible.

  In addition, the second drive unit 30 including the actuator mechanism 31 and the second voltage application unit 32 and the movable unit 15 according to the above-described embodiment can employ various modes as described in the following modifications. In addition, the 2nd drive part 30 is not limited to the following modifications, For example, you may be comprised so that the movable part 15 may be displaced with a motor etc.

<Modification 1>
Next, the 2nd drive part 30 and the movable part 15 as the modification 1 of this embodiment are demonstrated.
In the second drive unit 30 according to the first modification, as shown in FIGS. 10A and 10B, the actuator mechanism 31 is disposed on the same plane as the diaphragm 11, and is intermediate between the movable unit 15. The intermediate portion and the central portion (including the facing surface 15a) of the movable portion 15 are provided at both ends of the movable portion 15 so as to be displaced toward the side surface 11d of the diaphragm 11. This is a mechanism for deforming the elastic body 15b.

  Note that the elastic body 15 b of the first modification is configured as an elastic link portion that connects the intermediate portion of the movable portion 15 and the support portion 13 at both ends of the movable portion 15. Specifically, while the torsional vibration part 12 is twisted and deformed around the rotation axis k, the elastic body 15b as the elastic link part is operated substantially linearly with one degree of freedom as shown in FIG. It is configured. In the first modification, the elastic body 15b as the elastic link portion is arranged so as to operate substantially linearly in the direction of the rotation axis k on the same plane as the diaphragm 11.

  On the other hand, the actuator mechanism 31 according to the first modification is a rod-like structure in which a large number of piezoelectric elements are stacked on an elastic member, and is configured as a well-known piezoelectric actuator that increases its strain in the thickness direction in accordance with the applied voltage. Yes.

  The second voltage application unit 32 (see FIG. 3) of this modification is configured not to apply a drive voltage to the actuator mechanism 31 during normal driving. Thereby, since the actuator mechanism 31 as a piezoelectric actuator does not deform | transform, as shown to Fig.10 (a), the clearance gap distance d is maintained by default distance.

  On the other hand, a drive voltage is applied to the actuator mechanism 31 during excessive vibration. As a result, the actuator mechanism 31 as the piezoelectric actuator is deformed in the thickness direction, so that the movable portion 15 as the elastic link portion moves substantially linearly toward the rotation axis k as shown in FIG. Thus, the intermediate portion and the central portion (including the facing surface 15a) of the movable portion 15 are displaced toward the side surface 11d of the diaphragm 11, and the gap distance d can be reduced. In addition, the actuator mechanism 31 of the first modification may use a thermal actuator described in the following second modification, instead of the piezoelectric actuator.

<Modification 2>
Next, the 2nd drive part 30 and the movable part 15 as the modification 2 of this embodiment are demonstrated.
In the second drive unit 30 of the second modification example, as shown in FIGS. 12A and 12B, the actuator mechanism 31 forms an intermediate portion of the movable unit 15 as an elastic body 15b, and the ambient temperature is reduced. It is configured as a thermal actuator that deforms in the direction of the rotation axis k of the diaphragm 11 in accordance with the rise. The actuator mechanism 31 according to the second modification is provided with a heater 55.

  In addition, as shown in FIG. 13A, the actuator mechanism 31 according to the second modification includes a first rod-shaped member 51 formed in a rod shape using silicon as a material, and a second rod formed in a rod shape using silicon oxide as a material. The rod-shaped member 52 is configured to be stacked along a direction orthogonal to the longitudinal direction (hereinafter referred to as a stacking direction D1). In addition, the actuator mechanism 31 is formed so that the first rod-shaped member 51 and the second rod-shaped member 52 have, for example, a linear shape as an initial shape under a situation where the temperature is room temperature. The initial shape of the actuator mechanism 31 is not limited to this.

  The thermal expansion coefficients of silicon and silicon oxide are (2.6 × 10 −6) and (0.5 × 10 −6), respectively. For this reason, under the condition where the temperature is lower than the room temperature, as shown in FIG. 13B, silicon contracts more than silicon oxide (see arrow D2). Thus, when the temperature of the actuator mechanism 31 is lower than room temperature, the outer surface of the second rod-shaped member 52 (silicon oxide) is convex with the joint surface between the first rod-shaped member 51 and the second rod-shaped member 52 interposed therebetween. Bend.

  On the other hand, under a situation where the temperature is higher than room temperature, as shown in FIG. 13C, silicon expands more than silicon oxide (see arrow D3). Thereby, when the temperature becomes higher than the room temperature, the actuator mechanism 31 is configured such that the outer surface of the first rod-shaped member 51 (silicon) is convex with the joint surface between the first rod-shaped member 51 and the second rod-shaped member 52 interposed therebetween. Bend.

  In the second modification, the actuator mechanism 31 as a thermal actuator is arranged so that the stacking direction D1 faces the rotation axis k on the same plane as the vibration plate 11, and the second rod-shaped member 52 is twisted and vibrated. The first rod-like member 51 is disposed on the side closer to the portion 12 and on the side farther from the torsional vibration portion 12.

  In the above example, the first rod-like member 51 is a member made of silicon, and the second rod-like member 52 is a member made of, for example, silicon oxide formed by thermally oxidizing silicon. However, for example, the following configuration of the actuator mechanism 31 as a thermal actuator is also conceivable.

  Specifically, as shown in FIGS. 14A to 14C, an actuator mechanism 31 as a thermal actuator includes a silicon member 52a as a second rod-shaped member 52 formed in a rod shape using silicon as a material, It is comprised from the piezoelectric material member 51a as the 1st rod-shaped member 51 laminated | stacked on the surface of the 2 rod-shaped member 52 along the lamination direction D1.

  The piezoelectric member 51a includes a thin film piezoelectric element made of an insulator, and two electrodes stacked along the stacking direction D1 on the surface of the thin film piezoelectric element. Note that these electrodes are formed with a thickness smaller than that of the thin film piezoelectric element. Moreover, in the piezoelectric member 51a, platinum (Pt) is used as an electrode in contact with the upper surface of the silicon member 52a and the lower surface of the thin film piezoelectric element, and the electrode in contact with the upper surface of the thin film piezoelectric element. Gold (Au) is used. A constant voltage is applied with the Au electrode as the positive electrode and the Pt electrode as the negative electrode (GND).

  In the piezoelectric member 51a configured as described above, for example, in a situation where the temperature is room temperature, when a constant voltage is applied between the pair of electrodes, the thin film piezoelectric element expands. By adjusting the applied voltage, as shown in FIG. 14B, the magnitude of distortion of the piezoelectric member 51a under the room temperature condition can be determined as an initial value.

  On the other hand, a piezoelectric d constant (piezoelectric strain constant) is defined as a coefficient in the case of expressing the magnitude of strain generated when a constant voltage is applied in a state where no external stress is applied. In particular, among the piezoelectric strain constants, the d31 constant represents the rate at which the length of the thin film piezoelectric element changes, and is known to increase as the temperature increases (for example, “Tadao Shiogama,” Application ”See CMC Publishing, 2002”).

  That is, the d31 constant is not a constant value but has temperature dependence. For this reason, under a situation where the temperature is higher than room temperature, the thin film piezoelectric element can be expanded from the state at room temperature as shown in FIG. 14A (see arrow D4). Thereby, in the actuator mechanism 31, when the temperature becomes higher than room temperature, the outer surface of the piezoelectric member 51a is bent so as to be larger than the initial value across the joining surface between the piezoelectric member 51a and the silicon member 52a. Mu

  On the other hand, under the condition where the temperature is lower than room temperature, the thin film piezoelectric element can be contracted from the state at room temperature as shown in FIG. 14C (see arrow D5). As a result, when the temperature is lower than room temperature, the actuator mechanism 31 bends so that the outer surface of the piezoelectric member 51a is smaller than the initial value with the joint surface between the piezoelectric member 51a and the silicon member 52a interposed therebetween. Mu

  In the following, in order to avoid duplication of explanation, the actuator mechanism 31 will be described on the assumption that the first rod-like member 51 and the second rod-like member 52 are provided. The first rod-like member 51 is composed of the piezoelectric member 51a and the second rod-like member. It is assumed that the member 52 can be replaced with the silicon member 52a.

  Here, the second voltage application unit 32 (see FIG. 3) of the present modification does not apply a drive voltage to the heater 55 during normal driving. As a result, the ambient temperature becomes a temperature close to room temperature, and the actuator mechanism 31 as a thermal actuator is not deformed, so that the gap distance d is maintained at the default distance as shown in FIG.

  On the other hand, during excessive vibration, the environmental temperature is raised by applying a drive voltage to the heater 55. Thereby, at the time of high temperature, in the actuator mechanism 31 as a thermal actuator, the outer surface of the first rod-shaped member 51 (silicon) is convex with the joint surface between the first rod-shaped member 51 and the second rod-shaped member 52 interposed therebetween. By deforming, as shown in FIG. 12B, the central portion (including the facing surface 15a) of the movable portion 15 is displaced toward the side surface 11d of the diaphragm 11, and the gap distance d can be reduced. .

  Further, in the configuration in which the environmental temperature is raised by the heater 55 in this way, the viscosity increases as the temperature rises, so that the air resistance received by the side surface 11d of the diaphragm 11 can be further increased. When the amplitude in the state is reduced, the amplitude suspension time can be further shortened.

  In the second modification, for example, as shown in FIG. 15, the side surface 11 d of the diaphragm 11 and the facing surface 15 a of the movable portion 15 may be formed in a comb-teeth shape that meshes with each other with a predetermined interval. In this case, since the shear force of the air resistance received by the diaphragm 11 is proportional to the surface area, the shear force received by the diaphragm 11 can be increased more effectively. As a result, the air resistance received by the diaphragm 11 is further increased, and in the resonance type optical scanning device 10, when the amplitude of the diaphragm 11 in the resonance state is decreased, the amplitude reduction time can be further shortened. It becomes possible.

  DESCRIPTION OF SYMBOLS 1 ... Warning display system, 2 ... HUD apparatus, 3 ... Laser light source, 4 ... Distant expansion optical system, 8 ... Target probe, 10 ... Optical scanning apparatus, 10a ... Scanning mirror, 11 ... Diaphragm, 11a ... Light reflection 11b: inner gimbal, 11c: outer gimbal, 11d: side surface, 12 ... torsional vibration part, 12a ... first torsion elastic member, 12b ... second torsion elastic member, 12c ... third torsion elastic member, 13 ... support part , 13a, 13b, 13c ... fixed end, 14 ... mirror fixing frame, 15 ... movable part, 15a ... opposing surface, 15b ... elastic body, 20 ... first drive part, 21 ... electrostatic comb actuator with step, 21a ... Movable comb teeth, 21b ... fixed comb teeth, 22 ... first voltage application unit, 30 ... second drive unit, 31 ... actuator mechanism, 32 ... second voltage application unit, 32a ... movable side electrode unit, 32b ... fixed side electrode 40, amplitude sensor, 5 ... Amplitude control circuit, 51 ... first rod member, 51b ... thin film piezoelectric element, 52 ... second rod member, 52a ... silicon member, 55 ... heater, 60 ... damping force adjustment circuit, 70 ... control circuit, JS ... center of gravity, d: Clearance distance, h, i, j, k: Rotating shaft.

Claims (10)

A diaphragm having a scanning mirror for reflecting the light beam;
A pair of torsional vibration parts that are arranged on the same straight line passing through the center of gravity of the diaphragm and torsionally vibrate;
A support part for supporting the diaphragm via the torsional vibration part;
First driving means for generating a preset excitation force to resonate the diaphragm with the pair of torsional vibration portions as rotation axes;
A movable part having a facing surface facing the side surface of the diaphragm;
An actuator mechanism for displacing at least a part of the movable part including the facing surface in a direction in which the gap distance changes, wherein a distance between the facing surface and the side surface of the diaphragm is a clearance distance; Second driving means for generating a preset acting force by applying a voltage or heating a heater to increase the environmental temperature of the actuator mechanism ;
Control means for controlling the first drive means and the second drive means;
With
The control means sets the excitation force according to the target value when the amplitude of the diaphragm in the resonance state is maintained at the target value, and the amplitude reaches the target value when the amplitude is decreased. In the case of shortening the time until the optical scanning device, the acting force is set so that the gap distance is reduced.   The optical scanning device according to claim 1, wherein a side surface of the diaphragm is a surface having the largest distance from the rotation shaft. The movable portion has the opposed surface arranged in the center portion, and both end portions are fixed to the support portion, and a portion between the center portion and both end portions is defined as an intermediate portion. At least one of them is constituted by an elastic body,
It said second drive means, said as the actuator mechanism, according to claim 1, characterized in that it comprises the Ru Organization deforming the elastic member so that the central portion is displaced toward the side surface of the vibration plate of the movable portion Alternatively, the optical scanning device according to claim 2. The actuator mechanism is provided on at least one of the movable side electrode portion provided in at least one of the intermediate portion and the central portion of the movable portion, and the support portion and the diaphragm at a predetermined interval from the movable side electrode portion. The fixed-side electrode portion formed,
The second driving means applies a voltage between the movable side electrode portion and the fixed side electrode portion, thereby electrostatically acting between the movable side electrode portion and the fixed side electrode portion as the acting force. The optical scanning device according to claim 3, wherein an attractive force is generated. The movable electrode part is provided in an intermediate part of the movable part,
The optical scanning device according to claim 4, wherein the fixed-side electrode portion is fixed to the support portion. The movable electrode portion is provided in a central portion of the movable portion,
The optical scanning device according to claim 4, wherein the fixed-side electrode portion is provided on a side surface of the diaphragm. The actuator mechanism is a piezoelectric actuator that connects an intermediate part of the movable part and the support part, and increases its own strain according to an applied voltage,
4. The light according to claim 3, wherein the second driving unit applies a voltage to the piezoelectric actuator to cause the piezoelectric actuator to generate a tensile force with respect to a central portion of the movable portion as the acting force. Scanning device. The actuator mechanism is a thermal actuator that constitutes an intermediate part of the movable part as the elastic body, and is deformed toward the rotation axis of the diaphragm in response to an increase in environmental temperature,
The said 2nd drive means generates the driving force with respect to the center part of the said movable part to the said thermal actuator as said action force by heating a heater in order to raise environmental temperature, The said actuator is characterized by the above-mentioned. The optical scanning device described.   9. The light according to claim 1, wherein a side surface of the diaphragm and a facing surface of the movable portion are formed in a comb-teeth shape that meshes with each other at a predetermined interval. Scanning device. A head-up display device that has an optical scanning device that is mounted on a vehicle and scans a light beam, and displays an image made of video light emitted from the optical scanning device so that a passenger of the vehicle can visually recognize the image as a virtual image; ,
An in-vehicle control device that performs image display control in the head-up display device;
With
The in-vehicle control device outputs a reduction command for reducing the display image area when performing a warning display related to the traveling of the vehicle via the head-up display device,
The optical scanning device includes:
A diaphragm having a scanning mirror for reflecting the light beam;
A pair of torsional vibration parts that are arranged on the same straight line passing through the center of gravity of the diaphragm and torsionally vibrate;
A support part for supporting the diaphragm via the torsional vibration part;
First driving means for generating a preset excitation force to resonate the diaphragm with the pair of torsional vibration portions as rotation axes;
A movable part having a facing surface facing the side surface of the diaphragm;
An actuator mechanism for displacing at least a part of the movable part including the facing surface in a direction in which the gap distance changes, wherein a distance between the facing surface and the side surface of the diaphragm is a clearance distance; Second driving means for generating a preset acting force by applying a voltage or heating a heater to increase the environmental temperature of the actuator mechanism ;
Control means for controlling the first drive means and the second drive means;
With
When the control means maintains the amplitude in the resonance state of the diaphragm at a target value, the excitation means according to the target value is set, and by inputting a reduction command from the in-vehicle control device, A warning display system, wherein when the amplitude is reduced, when the time until the amplitude reaches a target value is shortened, the acting force is set so that the gap distance becomes small.