JP6938900B2 - Light deflector, image projection device, optical writing unit, object recognition device - Google Patents

Description

The present invention relates to a light deflector, an image projection device, an optical writing unit, and an object recognition device.

Conventionally, an optical deflector that scans a laser beam emitted from a light source in a two-dimensional direction has been known (see Patent Document 1).

The optical deflector includes a sub-scanning swing portion that swings around the sub-scanning swing axis and a mirror portion that swings around the circumferential swing shaft, and the sub-scan swing portion is provided with an arm in the sub-scanning direction. The mirror portion is supported by the support portion so as to be swingable, and the mirror portion is supported by the sub-scanning swing portion so as to be swingable around the main scanning swing axis by a plurality of beam portions. A piezoelectric part including a piezoelectric element is attached to the surface of each beam part, and the beam part is elastically deformed by the expansion and contraction of the piezoelectric element to swing the mirror part around the main scanning swing axis, and the sub-scanning swing. By swinging the portion around the sub-scanning axis, the laser beam incident on the mirror portion is scanned (deflected) in the two-dimensional direction.

By the way, in such an optical deflector, when an actuator such as a piezoelectric part fails, the scanning of the laser beam is stopped, the laser beam continues to be irradiated to one point in the scanning range, and the laser beam is emitted to one point in the predetermined range. There was a problem that if the laser was continuously irradiated, it would affect the device in the subsequent stage.

An object of the present invention is to prevent the light such as a laser beam from being continuously irradiated to a point within a predetermined range which is a scanning range when the actuator is abnormal.

The present invention includes a mirror unit having a reflecting surface, a plurality of actuators for driving the mirror unit around a predetermined axis, a drive control unit for controlling the drive of the plurality of actuators, and at least one of the plurality of actuators. one of the abnormality detecting unit for detecting an abnormality of the actuator, an optical deflecting device Ru wherein the actuator includes a first actuator which drives the mirror unit about a first axis, the second axis the mirror portion It has a second actuator that is driven around, and the abnormality detecting unit has a first abnormality detecting unit that detects an abnormality of the first actuator and a second abnormality detecting unit that detects an abnormality of the second actuator. and a failure detection unit, the drive control unit may detect one of an abnormality of the first abnormality detection portions and the second by the abnormality detecting unit Ri before Symbol first actuator or the second actuator when an optical deflecting device for controlling to deflect outside different predetermined range from the predetermined range of light beam incident on the mirror portion with the other actuator.

According to the present invention, when the actuator is abnormal, it is possible to prevent a point within a predetermined range, which is a scanning range, from being continuously irradiated with light such as a laser beam.

It is a top view which showed the structure of the light deflector used in the light deflector of 1st Example. It is a block diagram which showed the structure of the light deflecting apparatus of 1st Example provided with the optical deflector of FIG. It is explanatory drawing which showed typically the connection relationship of the electrode plate of the drive piezoelectric part. (A) is an explanatory diagram showing the positional relationship between the mirror portion and the base portion in the normal state, and (B) is an explanatory diagram showing the positional relationship between the mirror portion and the base portion in the abnormal state. It is explanatory drawing which showed the state which the laser beam is removed from the exit port at the time of abnormality. It is explanatory drawing which showed the other example of the light deflector. It is a block diagram which showed the structure of the head-up display device of 2nd Example. As a third embodiment, it is a schematic diagram schematically showing the configuration of the automobile equipped with the head-up display device provided with the light deflection device of the first embodiment. FIG. 5 is an optical layout diagram showing a configuration of the head-up display device shown in FIG. It is an optical layout diagram which showed the structure of the optical writing unit of 4th Example. It is explanatory drawing which showed the schematic structure of the image forming apparatus of 5th Example. It is a block diagram which showed the structure of the object recognition apparatus of 6th Example. It is explanatory drawing which showed the modification which provided the light receiving part as an abnormality detection part. It is explanatory drawing which showed the optical deflector when the piezoelectric part for forced drive is not provided. It is a flowchart which shows the flow of the anomaly processing performed by using the optical deflector of FIG. It is explanatory drawing which showed the other different example of a light deflector. It is explanatory drawing which showed the further different example of the light deflector.

Hereinafter, examples of embodiments of the light deflection device, the image projection device, the light writing unit, and the object recognition device according to the present invention will be described with reference to the drawings.

[First Example]
FIG. 1 shows the configuration of the light deflector 1 used in the light deflector 120 (see FIG. 2). The optical deflector 1 is a so-called MEMS device. The optical deflector 1 is supported by a frame-shaped substrate 2, a pair of elastic portions (second elastic portions) 3 and 4 formed in a meandering shape by a plurality of notches Ka and Kb, and the elastic portions 3 and 4. It has a pair of bases 5A and 5B. Further, a pair of mirror support portions (first elastic portions) 6A and 6B supported by the pair of base portions 5A and 5B, and a pair of torsions provided on the pair of mirror support portions 6A and 6B and supporting the mirror portion M. It has bars 7A and 7B. The substrate 2, the elastic portions 3, 4 and the base portions 5A and 5B, the mirror support portions 6A and 6B, and the torsion bars 7A and 7B are formed of one SOI substrate. Further, the mirror portion M is formed, for example, by depositing a metal thin film such as Ag or Al on the mirror base as a reflective surface, and the mirror base is formed from the above SOI substrate and integrally formed with the torsion bars 7A and 7B. There is.

A plurality of terminals T1 to T16 for driving a drive piezoelectric portion, which will be described later, are provided on the surface of one end side (right end side in FIG. 1) of the substrate 2.

The drive piezoelectric portion has, for example, a laminated structure of an upper electrode, a piezoelectric element, and a lower electrode, and when a driving voltage is applied to the piezoelectric element by the upper electrode and the lower electrode, the piezoelectric element deforms (expands and contracts). Then, the elastic portion is deformed to drive the mirror portion M.
[Elastic part 3]
The elastic portion 3 has a plurality of beam portions 3A1 to 3A4 arranged in parallel, one end (left end in FIG. 1) of the beam portion 3A1 is fixed to the substrate 2, and the left end portion of the beam portion 3A4 is the upper portion of the base portion 5A. It is fixed to. Further, the right end portions of the beam portions 3A1, 3A3 and the beam portions 3A2, 3A4 are connected by the connecting portion 3R1, and the left end portions of the beam portion 3A2 and the beam portion 3A3 are connected by the connecting portion 3R2.

A driving piezoelectric part (second driving part: auxiliary driving part) A1 is attached to the surface of the beam parts 3A1 and 3A3, respectively, and a driving piezoelectric part (second driving part: second driving part:) is attached to the surface of the beam parts 3A2 and 3A4. Auxiliary drive unit) B1 is attached to each.
[Elastic part 4]
The elastic portion 4 has a plurality of beam portions 4A1 to 4A4 arranged in parallel, the right end portion of the beam portion 4A1 is fixed to the substrate 2, and the right end portion of the beam portion 4A4 is the lower portion of the base portion 5B (in FIG. 1). It is fixed to. Further, the left end portions of the beam portions 4A1, 4A3 and the beam portions 4A2, 4A4 are connected by the connecting portion 4R1, and the right end portions of the beam portion 4A2 and the beam portion 4A3 are connected by the connecting portion 4R2.

Drive piezoelectric portions (second drive unit: sub-drive unit) B2 that elastically deform the beam portions 4A1 and 4A3 are attached to the surfaces of the beam portions 4A1 and 4A3, respectively. On the surface of the beam portions 4A2 and 4A4, a drive piezoelectric portion (second drive portion: auxiliary drive portion) A2 that elastically deforms the beam portions 4A2 and 4A4 is attached.

Different drive voltages are applied to the drive piezoelectric portions A1 and A2 and the drive piezoelectric portions B1 and B2. As a result, the beam portions 3A1 to 3A4, 4A1 to 4A4 are warped, and the adjacent beam portions 3A1 to 3A4, 4A1 to 4A4 are bent in different directions. This deflection is accumulated and the mirror portion M is greatly rotated around the X axis (second axis).

The rotation of the mirror unit M around the X axis enables scanning (deflection) of the reflected light of the mirror unit M in the vertical direction (Y-axis direction: sub-scanning direction). That is, the mirror portion M rotates around the X axis (second axis) orthogonal to the Y axis (first axis).

In this embodiment, four beam portions 3A1 to 3A4 and 4A1 to 4A4 are provided, but in reality, a larger number is provided, and only four are shown for convenience of explanation. Further, the drive piezoelectric portion need only be provided independently on each beam portion, and the size, shape, and arrangement are not limited to the above embodiment.

[Bases 5A, 5B]
Piezoelectric parts (forced drive parts) A3 and B3 for forced drive that forcibly elastically deform the bases 5A and 5B are attached to the bases 5A and 5B, respectively.

The base portions 5A and 5B support the mirror support portions 6A and 6B, and the mirror support portions 6A and 6B have a drive piezoelectric portion (first drive portion: main drive portion) that elastically deforms the mirror support portions 6A and 6B. ) A4 and B4 are attached respectively.

The mirror support portions 6A and 6B support the mirror portion M so as to be rotatable around the Y axis (first axis) via the torsion bars 7A and 7B. Due to the elastic deformation of the mirror support portions 6A and 6B, the mirror portion M swings around the Y axis (first axis) by resonance using the torsion bars 7A and 7B and the mirror support portions 6A and 6B. Due to this fluctuation, the reflected light of the laser beam (luminous flux) incident on the mirror portion M is scanned (deflected) in the X direction (main scanning direction) within a predetermined range.

Further, the base portions 5A and 5B are elastically deformed by the drive of the forced drive piezoelectric portions A3 and B3 to deflect the laser beam incident on the mirror portion M out of the above-mentioned predetermined range.

[Terminals T1 to T16]
The terminals T1 to T16 are for applying a voltage to the drive piezoelectric portions A1, A2, A4, B1, B2, B4 and the forced drive piezoelectric portions A3, B3. Drive power supplies 31 to 34 of the drive power supply unit 60 are connected to predetermined terminals of the terminals T1 to T16 via ammeters 41 to 44. The drive piezoelectric portions A1, A2, B1 and B2 are driven by these drive power supplies 31 to 34, and the forced drive piezoelectric portions A3 and B3 are driven by the forced drive power supply unit 35 (see FIG. 2). .. The forced drive power supply unit 35 is omitted in FIG.

The forced drive power supply unit 35 applies a voltage to the forced drive piezoelectric units A3 and B3 via predetermined terminals of the terminals T1 to T16. Similarly, the driving piezoelectric units A4 and B4 are also driven by the driving power supply unit 60 (see FIGS. 1 and 2). The drive power supply unit 60 applies a voltage to the drive piezoelectric units A4 and B4 via predetermined terminals different from the above among the terminals T1 to T16.

[Light deflector 120]
FIG. 2 is a block diagram schematically showing the configuration of the light deflector 120. The optical deflector 120 includes an optical deflector 1 shown in FIG. 1 and an optical scanning drive control unit 16.

The optical scanning drive control unit 16 includes an abnormality detection unit 70 for detecting an abnormality in the drive piezoelectric units A1, A2, B1, B2, A4, and B4, a drive power supply unit 60, a forced drive power supply unit 35, and a drive control unit. Has 80 and.

The drive power supply unit 60 has drive power supplies 31 to 34 (see FIG. 1) and drives the drive piezoelectric units A1, A2, B1, B2, A4, and B4. The forced drive power supply unit 35 drives the forced drive piezoelectric units A3 and B3. The drive control unit 80 is realized by, for example, a CPU, ROM, RAM, FPGA, or the like, and drives and controls the drive power supply unit 60 and the forced drive power supply unit 35 based on a signal or the like input from the outside.

[Abnormality detection unit 70]
The abnormality detection unit 70 includes a current detection unit (first abnormality detection unit) 50 and a current detection unit (second abnormality detection unit) 51 to 54. The current detection unit 50 detects an abnormality by detecting the current flowing through the drive piezoelectric units A4 and B4, which are the main drive units.

The current detection units 51 to 54 detect abnormalities in the drive piezoelectric units A1, A2, B1 and B2, which are sub-drive units, and are based on the current flowing through the ammeters 41 to 44, that is, the potential difference generated at both ends of the resistor. It detects anomalies. Similarly, the current detecting unit 50 also detects the potential difference generated at both ends of the resistor to detect the abnormality of the driving piezoelectric units A4 and B4.

[Drive control unit 80]
The drive control unit 80 controls the drive power supply unit 60 to swing the mirror unit M of the optical deflector 1 in the X-axis direction (see FIG. 1) and the Y-axis direction, and causes the mirror unit M of the optical deflector 1 to swing. The laser beam incident on the is scanned (deflected) in the X and Y directions. At this time, the mirror support portions 6A and 6B and the drive piezoelectric portions A4 and B4 function as the first actuator for driving the mirror portion M around the axis (Y-axis) parallel to the Y-axis, and the elastic portions 3 and 3 4 and the drive piezoelectric portions A1, A2, B1 and B2 function as a second actuator that drives the mirror portion M around an axis parallel to the X axis (around the X axis).

When the abnormality detection unit 70 detects an abnormality, the forced drive power supply unit 35 is turned on to drive the forced drive piezoelectric units A3 and B3, which are the forced drive units.

At this time, the forced drive piezoelectric portions A3 and B3 and the base portions 5A and 5B function as a third actuator for driving the mirror portion M.

When the forced drive piezoelectric portions A3 and B3 are driven, the base portions 5A and 5B are elastically deformed and the laser light incident on the mirror portion M is out of the predetermined range, that is, the laser light is emitted from the laser light emission port 9 (see FIG. 5). Is not displayed.

[Operation of light deflector 120]
Next, the operation of the light deflector 120 configured as described above will be described.

When a start switch (not shown) is operated, the drive control unit 80 outputs a drive voltage of a predetermined drive frequency from the drive power supply unit 60 to drive the drive piezoelectric units A4 and B4, and causes the mirror unit M to be Y-axis. Rotate it around. Further, the drive control unit 80 outputs a predetermined drive voltage from the drive power supplies 31 to 34 of the drive power supply unit 60 to drive the drive piezoelectric units A1, A2, B1 and B2.

By driving the drive piezoelectric parts A1, A2, B1 and B2, the mirror part M is rotated around the X axis. Then, due to the rotation of the mirror unit M around the Y axis and the X axis, the laser beam incident on the mirror unit M is reflected by the mirror unit M and scanned in the X and Y directions within a predetermined range. (Normal operation).

By the way, FIG. 3 schematically shows the connection relationship between the electrode plates of the driving piezoelectric portions A1 and B1, and the electrode plates A1b and B1b of the driving piezoelectric portions A1 and B1 are wired from the contact holes AP and BP. It is connected in series by the wiring AD and BD. Further, the electrode plates A1g and B1g for the ground of the driving piezoelectric portions A1 and B1 are connected in series by the wiring GD wired from the contact holes APg and BPg.

The piezoelectric films (piezoelectric elements) AU and BU of the drive piezoelectric parts A1 and B1 are dielectric layers and usually have a high resistance value, but when there is aged deterioration or initial failure, an internal defect occurs and the piezoelectric part May cause a short circuit and malfunction. In particular, the above-mentioned defects are likely to occur in an in-vehicle environment where the product is used in a high temperature environment.

As a defective mode, it is considered that the stress applied to the piezoelectric films AU and BU becomes non-uniform due to the decrease in the adhesion between the electrode plates A1b, A1g, B1b and B1g and the piezoelectric films AU and BU. In addition, cracks exist as initial defects inside the piezoelectric films AU and BU, cracks grow due to repeated expansion and contraction of the piezoelectric films AU and BU, and there are parts with non-uniform polarization as initial defects during operation. It is conceivable that the internal stress of the

Further, since the current is concentrated at the joint portion between the wiring AD, BD, GD and the electrode plates A1b, A1g, B1b, B1g, the amount of heat generated is large, and the wiring AD, BD, GD may be short-circuited.

These defects are the same for the driving piezoelectric parts A2 and B2 and the driving piezoelectric parts A4 and B4.

When the above-mentioned defect occurs, the power supply to the piezoelectric films AU and BU is stopped. Further, when the electrode plate (not shown) for the ground of the driving piezoelectric parts A4 and B4 is shared by the wiring GD, the piezoelectric film (not shown) of the driving piezoelectric parts A4 and B4 is applied. Since the power supply is also stopped, the operation of the mirror unit M is stopped.

When the operation of the mirror unit M is stopped, there is a problem that the laser beam continues to be irradiated to one point within a predetermined range which is a scanning range.

However, when the above-mentioned defect occurs, the current value increases significantly in the case of a short circuit, the current value detected by the current detection units 51 to 54 increases, and the detected current becomes zero when the wire breaks.

When any of the currents flowing through the driving piezoelectric parts A1, A2, B1, B2, A4, and B4 fluctuates significantly with respect to the fluctuation of the applied voltage of the driving piezoelectric parts A1, A2, B1, B2, A4, and B4. The drive control unit 80 determines that an abnormality has occurred. In this judgment, for example, when the fluctuation is 10% or more with respect to the current value when the voltage is applied, it is judged that there is an abnormality.

When the drive control unit 80 determines that an abnormality has occurred, it turns on the forced drive power supply unit 35 to apply a forced drive voltage to the forced drive piezoelectric units A3 and B3 (see FIG. 1). As a result, the forced drive piezoelectric portions A3 and B3 are driven, and the base portions 5A and 5B are elastically deformed from the position shown in FIG. 4A to the position shown in FIG. 4B. Due to this elastic deformation, as shown in FIG. 4B, the mirror portion M is greatly tilted. For example, by applying a positive voltage to one electrode of the forced drive piezoelectric portion A3 and applying a negative voltage to one electrode of the forced drive piezoelectric portion B3, the base portion 5A is elastically deformed downward in FIG. However, the base portion 5B can be elastically deformed upward. As a result, the mirror portion M can be greatly tilted.

As shown in FIG. 5, the laser light reflected by the mirror unit M due to the inclination of the mirror unit M moves on the laser light detection CCD 81 outside the exit port (predetermined range) 9 which is a predetermined scanning range (as shown in FIG. 5). Be biased). That is, the laser beam is deflected out of the predetermined range. In FIG. 5, reference numeral 14 denotes an optical system for irradiating the mirror unit M with laser light emitted from a laser light source (not shown). Further, by moving the laser light detection CCD 81 onto the laser light detection CCD 81, it is possible to confirm from the signal of the laser light detection CCD 81 whether the laser light source is on or off by deflecting out of the predetermined range.

Here, the relationship between the displacement amount of the base portions 5A and 5B and the inclination of the mirror portion M is such that the center of the mirror portion M is located between the center of the mirror portion M and the base portions 5A and 5B (the center of the mirror portion M is located between the base portions 5A and the base portion 5B). It depends on the distance to the forced drive piezoelectric parts A3 and B3. For example, when this distance is 1 mm, the displacement amount of the forced drive piezoelectric portions A3 and B3 = tanθ. Therefore, when the mirror portion M is tilted by, for example, θ = 10 degrees, the laser beam deviates from the outlet 9. The forced drive piezoelectric portions A3 and B3 may be displaced by 0.17 mm.

In this way, when an abnormality occurs in any of the driving piezoelectric portions A1, A2, B1, B2, A4, and B4, the forced driving piezoelectric portions A3 and B3 are driven to forcibly elasticize the base portions 5A and 5B. Transform. Therefore, the laser light incident on the mirror portion M can be deflected out of the predetermined range by an operation different from the normal operation, and it is possible to prevent the problem that the laser light continues to irradiate one point within the predetermined scanning range. be able to.

Further, the base portions 5A and 5B of the optical deflector 1 are provided with the piezoelectric portions A3 and B3 for forced driving, and the base portions 5A and 5B are elastically deformed to deflect the laser beam incident on the mirror portion M out of the predetermined range. The light deflector 120 is inexpensive because it is only made in this way.

In the above embodiment, the optical deflector 1 that scans in the two-dimensional directions, which are the X and Y directions, is provided with the piezoelectric parts A3 and B3 for forced driving, but the optical deflector that scans in the one-dimensional direction is also used. Applicable.

[Other examples]
FIG. 6 shows another example of the light deflector 1. The optical deflector 1 shown in FIG. 6 is reinforced with reinforcing ribs (reinforcing members) 90 so that the base portions 5A and 5B and the mirror support portions 6A and 6B maintain the same surface. This is because it is premised that the mirror support portions 6A and 6B are tilted according to the elastic deformation of the base portions 5A and 5B, so that the rigidity of the substrate 2 of the optical deflector 1 may not be sufficient. Therefore, the mirror support portions 6A and 6B may be twisted, and in order to prevent this, the mirror support portions 6A and 6B are reinforced with the reinforcing ribs 90.

[Second Example]
FIG. 7 is a block diagram showing a configuration of a head-up display device 100 including the light deflection device 120 of the first embodiment.

The head-up display device 100 of the second embodiment includes an optical deflector 1, a laser light source 12 that emits laser light, a light source drive control unit 13 that controls the laser light source 12, an optical system 14, and a control unit 19. , A light detection unit 20 is provided.

The light source drive control unit 13 controls on / off of the laser light source 12 and the like based on the image signal and the synchronization signal from the control unit 19.

The control unit 19 includes an image signal calculation unit 18, a detection signal calculation unit, 101, and an optical scanning drive control unit 16.

The image signal calculation unit 18 separates the horizontal synchronization signal and the vertical synchronization signal from the image signal.

The detection signal calculation unit 101 determines the timing at which the photodetection unit 20 receives the light scanned by the mirror unit M (see FIG. 1 and the like).

The optical scanning drive control unit 16 is a mirror unit M of the optical deflector 1 so that the horizontal synchronization signal from the image signal calculation unit 18 and the light reception timing of the light detection unit 20 obtained by the detection signal calculation unit 101 match. Controls the swing around the Y axis. Further, the swing of the mirror portion M of the optical deflector 1 around the X axis is controlled based on the vertical synchronization signal.

Then, the optical deflector 1 and the optical scanning drive control unit 16 of the control unit 19 constitute an optical deflector 120 similar to that of the first embodiment. Since the light deflector 120 operates in the same manner as in the first embodiment, the description thereof will be omitted.

The head-up display device 100 scans the reflected light of the laser beam incident from the optical system 14 in the main scanning direction and the sub-scanning direction by swinging the mirror portion M of the optical deflector 1 around the Y-axis and the X-axis. Is. As a result, the image of the image signal input to the image signal calculation unit 18 is projected on the projection surface 15.

Since the head-up display device 100 includes the light deflection device 120, the same effect as that of the first embodiment can be obtained. That is, when an abnormality occurs in any of the driving piezoelectric portions A1, A2, B1, B2, A4, and B4 (see FIG. 1), the forced driving piezoelectric portions A3 and B3 elastically deform the base portions 5A and 5B. , The laser beam incident on the mirror portion M is deflected out of a predetermined range. Therefore, it is possible to prevent a problem that the laser beam continuously irradiates one point of the projection surface 15 which is a predetermined scanning range.

[Third Example]
FIG. 8 is a schematic view schematically showing the configuration of an automobile equipped with a head-up display device 200, which is an image projection device provided with the light deflector 1 of the first embodiment, as a third embodiment. Further, FIG. 9 is a schematic view schematically showing the internal configuration of the head-up display device 200.

The head-up display device 200 of the third embodiment is installed in the dashboard of the automobile 301, for example, as shown in FIG. The projected light L, which is the image light emitted from the head-up display device 200 in the dashboard, is reflected by the windshield 302 and directed toward the observer (driver 300) who is the user. As a result, the driver 300 can visually recognize the image projected by the head-up display device 200 as a virtual image. A combiner may be installed on the inner wall surface of the windshield 302 so that the user can visually recognize the virtual image by the projected light reflected by the combiner.

As shown in FIG. 9, the head-up display device 200 of the third embodiment includes red, green, and blue laser light sources 201R, 201G, 201B, and collimator lenses 202, 203, 204 provided for each laser light source. It is composed of two dichroic mirrors 205 and 206, a light amount adjusting unit 207, a light deflector 1, a free curved mirror 209, a screen 210, and a projection mirror 211. In the light source unit 230 as the light source device in this embodiment, the laser light sources 201R, 201G, 201B, the collimator lenses 202, 203, 204, and the dichroic mirrors 205, 206 are unitized by an optical housing.

The head-up display device 200 of this embodiment projects an intermediate image displayed on the screen 210 (corresponding to the projection surface 15 shown in FIG. 7) onto the windshield 302 of the automobile 301, thereby displaying the intermediate image to the driver. Make 300 visually recognize it as a virtual image. The laser light of each color emitted from the laser light sources 201R, 201G, and 201B is regarded as substantially parallel light by the collimator lenses 202, 203, and 204, respectively, and is combined by the two dichroic mirrors 205 and 206. The combined laser light is two-dimensionally scanned by the light deflector 1 after the light amount is adjusted by the light amount adjusting unit 207. The projected light L two-dimensionally scanned by the light deflector 1 is reflected by the free-form surface mirror 209 to correct the distortion, and then is condensed on the screen 210 to display an intermediate image. The screen 210 is composed of a microlens array in which microlenses are two-dimensionally arranged, and magnifies the projected light L incident on the screen 210 in microlens units.

The optical deflector 1 is driven and controlled in the same manner as in the first embodiment, the mirror unit M is reciprocally rotated in the main scanning direction and the sub-scanning direction, and the projected light L incident on the mirror unit M is two-dimensionally scanned (raster scan). )do. The drive control of the light deflector 1 is performed in synchronization with the light emission timing of the laser light sources 201R, 201G, and 201B.

Further, the light source unit 230 of the third embodiment is a unitization of the laser light source 12 (see FIG. 7) and the optical system 14 of the second embodiment. The head-up display device 200 of the third embodiment is the head-up display device 100 of the second embodiment provided with a light amount adjusting unit 207, a free-form surface mirror 209, and a projection mirror 211.

The head-up display device 200 is not limited to a vehicle, but is, for example, a moving body such as an aircraft, a ship, or a mobile robot, or a non-moving body such as a working robot that operates a drive target such as a manipulator without moving from the place. It can also be applied as an image projection device mounted on the.

Further, in the third embodiment described above, the head-up display as an example of the image projection device has been described, but the device that projects an image by performing optical scanning using the optical deflector 1 of the first embodiment. It suffices, and is not limited to the above-described embodiment. For example, it can be similarly applied to a projector that projects an image on a display screen, a head-mounted display that projects an image on a screen such as a reflection / transmission member of a mounting member mounted on an observer's head or the like. can.

According to the third embodiment, by providing the light deflector 1, the same effect as that of the first embodiment can be obtained. That is, when an abnormality occurs in any of the driving piezoelectric parts A1, A2, B1, B2, A4, and B4 (see FIG. 1), the forced driving piezoelectric parts A3 and B3 are driven to force the bases 5A and 5B. Elastically deforms. Therefore, the laser light incident on the mirror portion M can be deflected out of the predetermined range, and it is possible to prevent the problem that the laser light continues to irradiate one point of the screen 210 which is the predetermined scanning range. As a result, it is possible to prevent the laser beam that continuously irradiates one point from entering the eyes of the driver 300.

[Fourth Example]
FIG. 10 shows the optical writing unit 1000 of the fourth embodiment. In the optical writing unit 1000, the laser light from the light source unit 1020 such as a laser element is deflected by the optical deflector 1022 after passing through the imaging optical system 1021 such as a collimator lens. As the optical deflector 1022, the optical deflector 1 (see FIG. 1) of the first embodiment is used, and the optical deflector 120 (see FIG. 2) of the first embodiment is used. In this case, the optical scanning drive control unit 16 drives and controls only the driving piezoelectric units A4 and B4 of the mirror support portions 6A and 6B of the optical deflector 1 (1022) so that the reflected light of the laser beam is directed only in the main scanning direction. Make it scan. As the optical deflector 1022, the optical deflector 1 of another example shown in FIG. 6 can also be used.

Then, the laser beam deflected by the light deflector 1022 passes through the scanning optical system 1023 including the first lens 1023a, the second lens 1023b, and the reflection mirror portion 1023c, and then the beam of the photoconductor drum 1002, which is the surface to be scanned. The scanning surface is irradiated. The scanning optical system 1023 forms a spot-shaped light beam on the beam scanning surface, which is the surface to be scanned.

Each electrode of the piezoelectric portion of the optical deflector 1022 is electrically connected to a mirror driving means such as an external power supply, and the mirror driving means applies a driving voltage between the upper electrode and the lower electrode of the piezoelectric portion. , Drives the light deflector 1022. As a result, the mirror portion M of the optical deflector 1022 reciprocates to deflect the laser beam, and the light is scanned on the beam scanning surface of the photoconductor drum 1002, which is the surface to be scanned.

As described above, the optical writing unit 1000 of this embodiment can be used as an optical writing unit for an image forming apparatus such as a printer or a copying machine using a photoconductor. In addition, by making the scanning optical system different so that light can be scanned not only in the uniaxial direction but also in the biaxial direction, the laser beam is deflected to the thermal media to irradiate the thermal media, and the light of the laser label device that prints by heating is applied. It can be used as a constituent member of the scanning unit.

In this fourth embodiment, the optical deflector 1 shown in FIG. 1 is used, but a dedicated optical deflector that scans the reflected light of the laser beam only in the main scanning direction may be used.

According to the fourth embodiment, since the optical writing unit 1000 uses the optical deflector 120 (see FIG. 2) provided with the optical deflector 1 as in the first embodiment, the driving piezoelectric portions A1, A2, When an abnormality occurs in any of B1, B2, A4, and B4 (see FIG. 1), the forced driving piezoelectric portions A3 and B3 are driven to forcibly elastically deform the base portions 5A and 5B. The laser beam incident on the mirror portion M can be deflected out of a predetermined range. Therefore, it is possible to prevent a problem that the laser beam is continuously irradiated to one point on the photoconductor drum 1002.

[Fifth Example]
FIG. 11 shows an example of the image forming apparatus 1300 of the fifth embodiment using the optical writing unit of the fourth embodiment.

In the image forming apparatus 1300 of the fifth embodiment shown in FIG. 11, the optical writing unit 1301 emits a laser beam to the surface to be scanned to write an image. The photoconductor drum 1302 is an image carrier that provides a surface to be scanned as a scanning target by the optical writing unit 1301. The optical writing unit 1301 scans the surface of the photoconductor drum 1302, which is the surface to be scanned, with one or a plurality of laser beams modulated by the recording signal in the axial direction of the drum. The photoconductor drum 1302 is rotationally driven in the direction of the arrow, and an electrostatic latent image is formed by light scanning the surface charged by the charging means 303 with the optical writing unit 1301. This electrostatic latent image is visualized as a toner image by the developing means 304, and the toner image is transferred to the recording paper P by the transfer means 305. The transferred toner image is fixed on the recording paper P by the fixing means 306. Residual toner is removed from the surface portion of the photoconductor drum 1302 that has passed through the transfer means 305 by the cleaning unit 307. It is also possible to use a belt-shaped photoconductor instead of the photoconductor drum 1302. It is also possible to transfer the toner image to a transfer medium other than the recording paper once, and then transfer the toner image from the transfer medium to the recording paper to fix the toner image.

The optical writing unit 1301 includes a light source 308 that emits one or a plurality of laser beams modulated by a recording signal, a light source driving means 309 that modulates the light source 308, and an optical deflector 310 (1022) of the above embodiment. An imaging optical system 311 for forming an image of a laser beam modulated by a recording signal from a light source 308 on the mirror surface of the mirror substrate of the light deflector 310, and one or more reflected on the mirror surface. It is composed of a scanning optical system 312 or the like, which is a means for forming a laser beam on the surface of a light source drum (light source) 1302, which is a surface to be scanned. The optical deflector 310 is incorporated in the optical writing unit 1301 in a form of being mounted on the circuit board 314 together with the integrated circuit 313 for driving the optical deflector 310.

The integrated circuit 313 includes the optical scanning drive control unit 16 shown in FIG. 2, and the optical deflector 310 has the same configuration as the optical deflector 1 of the first embodiment, and is the same as that of the first embodiment. Is driven and controlled.

Since the light deflector 310 according to the present embodiment consumes less power for driving than the rotary multifaceted mirror, it is advantageous for power saving of the image forming apparatus. Since the wind noise during vibration of the mirror substrate of the optical deflector is smaller than that of the rotating multifaceted mirror, it is advantageous for improving the quietness of the image forming apparatus. The installation space of the optical deflector is overwhelmingly smaller than that of the rotating multi-sided mirror, and the amount of heat generated by the optical deflector 310 is small, so that it is easy to miniaturize, which is advantageous for miniaturization of the image forming apparatus. be. The recording paper transport mechanism, the photoconductor drum drive mechanism, the developing means, the control means such as the transfer means, the drive system of the light source unit, and the like are omitted in the drawing because they may be the same as those of the conventional image forming apparatus.

According to the fifth embodiment, the optical deflector 310 has the same configuration as the optical deflector 1 of the first embodiment, and is driven and controlled in the same manner as that of the first embodiment. When an abnormality occurs in any of A2, B1, B2, A4, and B4 (see FIG. 1), the forced drive piezoelectric portions A3 and B3 are driven to forcibly elastically deform the bases 5A and 5B. Therefore, the laser beam incident on the mirror portion M can be deflected out of the predetermined range. Therefore, it is possible to prevent a problem that the laser beam is continuously irradiated to one point on the photoconductor drum 1302.

[Sixth Example]
FIG. 12 shows the object recognition device 600 of the sixth embodiment using the light deflector of the first embodiment.

The object recognition device 600 of the sixth embodiment lightly scans the laser beam (measured luminous flux) in the target direction using an optical deflector, and receives the reflected light from the object existing in the target direction to receive the object. It is a device that recognizes objects. FIG. 12 is a schematic diagram schematically showing the configuration of a laser radar which is an example of the object recognition device 600 of this embodiment.

As shown in FIG. 12, the laser light emitted from the laser light source 601 is scanned in the uniaxial or biaxial direction by the light deflector 610 through the collimating lens 602, which is an optical system in which the divergent light is substantially parallel light. , The object 650 in front of the vehicle is irradiated. The photodetector 605 receives the laser beam reflected by the object 650 and passed through the condenser lens 606, and outputs a detection signal. The laser driver 603, which is a light source driving unit, drives the laser light source 601 and the deflector driver 607, which is an optical deflector driving unit, drives the optical deflector 610. The light deflector 610 has the same configuration as the light deflector 1 of the first embodiment.

The controller 604 controls the laser driver 603 and the deflector driver 607 and processes the detection signal output from the photodetector 605. That is, the controller 604 calculates the distance to the object 650 based on the difference between the timing at which the laser beam is emitted and the timing at which the laser beam is received by the photodetector 605. By scanning the laser beam with the light deflector 610, the distance to the object 650 in a one-dimensional or two-dimensional range can be obtained. As described above, the radar device can be provided by using the light deflector 610 which is hard to be damaged. Such an object recognition device 600 is attached to, for example, the front side of the vehicle, and can monitor the front of the vehicle to recognize the presence or absence of obstacles in the front direction.

Further, the controller 604 and the deflector driver 607 constitute the optical deflector 120 of the first embodiment, and the optical deflector 610 is driven and controlled by the controller 604 in the same manner as in the first embodiment.

According to the sixth embodiment, the optical deflector 610 has the same configuration as the optical deflector 1 of the first embodiment, and is driven and controlled by the controller 604 in the same manner as in the first embodiment. Effect can be obtained.

That is, when an abnormality occurs in any of the driving piezoelectric parts A1, A2, B1, B2, A4, and B4 (see FIG. 1), the forced driving piezoelectric parts A3 and B3 are driven to force the bases 5A and 5B. Since it is elastically deformed, the laser beam incident on the mirror portion M can be deflected out of a predetermined range. Therefore, it is possible to prevent a problem that the laser beam is continuously irradiated to one point of the object 650.

In the sixth embodiment described above, the laser radar as an example of the object recognition device has been described, but the reflected light is emitted by performing light scanning in the target direction using the optical deflector 1 of the first embodiment and other examples. Any device that recognizes an object by receiving light may be used, and the device is not limited to the above-described embodiment. For example, biometric authentication that recognizes an object by referring to the information obtained by optical scanning of the hand or face as a record, a security sensor that recognizes an intruder by optical scanning in the direction of the object, and optical scanning are obtained. The same can be applied to constituent members of a three-dimensional scanner that recognizes the shape of an object from the distance information and outputs it as three-dimensional data. Further, the presence / absence and shape of the object may be recognized from the light intensity of the reflected light received by the light receiving unit, the change in wavelength due to the reflection, and the like.

The second to sixth embodiments have been described above as a mode in which light scanning is performed using the optical deflector 1 of the first embodiment. However, a device that deflects light to perform light scanning one-dimensionally or two-dimensionally. If so, it is possible to apply the optical deflector 1 of the first embodiment.

The present invention is not limited to the above-described embodiment, and design changes and additions are permitted as long as the gist of the invention is not deviated from the scope of claims.

For example, in each of the embodiments described above, the abnormality of each actuator is detected by the current detection units 50 to 54, but as the abnormality detection unit, a light receiver (for example, a CCD for laser light detection) is placed on the scanned surface of the photodetector. Or a photodiode, etc.), the light from the light source may be reflected by the mirror unit M, and the reflected light may be received by the photoreceiver to detect an abnormality in the actuator.

For example, as shown in FIG. 13, the surface to be scanned of the scanning light L'from the optical deflector (for example, the optical deflector 1 of the first embodiment can be used) can be scanned by the optical deflector. Receivers 703a to 703d are provided in a region 702 of the scanning region 700, which is outside a predetermined region (region externally output as an image) 701 used for image drawing by the optical deflector. At this time, when a predetermined applied signal is applied to the actuator, the drive control unit determines whether or not both the light receiver 703a and the light receiver 703b receive light in the main scanning direction (X direction in FIG. 13). When the light receivers 703a and 703b cannot receive light in the predetermined applied signal range, it detects that the actuator in the main scanning direction is abnormal. In the sub-scanning direction (Y direction in FIG. 13), the receivers 703c and 703d similarly detect an abnormality. At this time, the photoreceivers 703a and 703b function as a first abnormality detecting unit for detecting an abnormality in the main scanning direction, and the photoreceivers 703c and 703d function as a second abnormality detecting unit for detecting an abnormality in the sub-scanning direction.

It suffices if an abnormality in the actuator can be detected using the light receiver. For example, when the light receiver 703a receives light twice, the time of each light reception is recorded, and the time difference and the predetermined time difference in the predetermined applied signal are recorded. If the deviation is larger than the threshold value, it may be detected as abnormal.

Further, in each of the examples described above, a method of providing the forced drive piezoelectric portions A3 and B3 in the optical deflector 1 as a method of deflecting the laser beam incident on the mirror portion M out of the predetermined range has been described. However, the method is not limited to this method. For example, in the case of the optical deflector 1 that scans in the two-dimensional directions of the main scanning direction and the sub-scanning direction as shown in FIG. 14, the piezoelectric portion in the main scanning direction fails. A method of deflecting the laser beam incident on the mirror portion M to the outside of the predetermined range by the piezoelectric portion in the sub-scanning direction when the above is detected may be applied. As a result, the laser beam can be deflected to a non-predetermined position without newly providing the forced drive piezoelectric portions A3 and B3.

In the case of an optical deflector that scans in a two-dimensional direction by the above-mentioned plurality of actuators, when an abnormality in one actuator is detected, the laser beam incident on the mirror portion M is deflected out of a predetermined range by using the other actuator. An example of the modification to be performed will be described in detail below.

As shown in FIG. 14, the optical deflector 1 includes a first actuator (mirror support portions 6A and 6B and drive piezoelectric portions A4 and B4) for moving the mirror portion M around an axis parallel to the X axis, and a mirror. It has a second actuator (elastic portions 3 and 4 and drive piezoelectric portions A1, A2, B1, B2) that move the portion M around an axis parallel to the Y axis. As the first and second abnormality detection units, current detection units 50 to 54 similar to those of the optical deflector 1 of the first embodiment may be used, or receivers 703a to 703d shown in FIG. 13 may be used. ..

The flow of the abnormal processing performed by the optical deflector 1 will be described with reference to the flowchart of FIG. As shown in FIG. 15, first, the first and second abnormality detection units detect whether or not the first and second actuators are abnormal (step S1). When an abnormality is detected in any one of the actuators (determination in step S2 is YES), the laser beam is deflected outside the predetermined region by the other actuator in which no abnormality is detected (step S3). On the other hand, when no abnormality is detected in any of the first and second actuators (determination in step S2 is NO), the abnormality processing ends.

More specifically, when the abnormality of the first actuator is detected by the first abnormality detection unit and the abnormality of the second actuator is not detected by the second abnormality detection unit, the second actuator is used. The mirror portion M is tilted in the sub-scanning direction to deflect the laser beam out of the predetermined region.

Further, when the abnormality of the second actuator is detected by the second abnormality detecting unit and the abnormality of the first actuator is not detected by the first abnormality detecting means, the mirror unit M is detected by the first actuator. It is tilted in the main scanning direction to deflect the laser beam out of the predetermined area. In this way, by deflecting the laser beam outside the predetermined region that easily affects the subsequent device, it is possible to prevent the laser beam from concentrating at one point in the predetermined region.

At this time, even outside the predetermined region, it is preferable to use an actuator in which no abnormality is detected to perform optical scanning within a range that does not enter the predetermined region. Further, it is preferable that the light receiver (for example, the light receivers 703a to 703d shown in FIG. 13) is included in this optical scanning range. As a result, it is possible to suppress the concentration of the laser light at one point even outside the predetermined region and suppress the influence on the subsequent parts, and it is possible to detect the state of the light source by receiving the laser light with the light receiver.

In each of the above embodiments, the actuator is a piezoelectric drive type actuator using a piezoelectric element, but the actuator is not limited to this. For example, an electromagnetic drive type actuator using an electromagnetic force or an electrostatic drive type actuator using an electrostatic force may be adopted.

Further, a detection actuator having a detection piezoelectric portion is provided separately from the actuator having the drive piezoelectric portion, and when the drive control unit detects an abnormality of the actuator, the detection piezoelectric portion is used for optical scanning. You may go. For example, as in another different modification shown in FIG. 16, the detection piezoelectric portions C1 and D1 are provided in the elastic portions 3 and 4 in parallel with the driving piezoelectric portions A1 and B1. In this case, the driving piezoelectric portions A1 and B1 and the elastic portions 3 and 4 function as the first actuator for driving the mirror portion M around a predetermined axis, and the detecting piezoelectric portions C1 and D1 and the elastic portions 3 and 4 function. However, it functions as a detection actuator (second actuator) that drives the mirror unit M in an operation different from the normal operation. The detection piezoelectric units C1 and D1 also function as abnormality detection units. The detection piezoelectric units C1 and D1 utilize the piezoelectric effect. As the elastic portions 3 and 4 are deformed by the expansion and contraction of the drive piezoelectric portions A1 and B1, the detection piezoelectric portions C1 and D1 are deformed to generate an electric charge. The amount of warpage of the elastic portions 3 and 4 and the inclination angle of the movable portion are calculated. Further, the drive control unit monitors each of the elastic units 3 and 4, so that the total amount of displacement generated by the drive piezoelectric units A1 and B1 can be detected.

At this time, the detection piezoelectric units C1 and D1 are connected to a drive power supply separate from the drive power supply connected to the drive piezoelectric units A1 and B1, and the separate drive power supply is connected to the drive control unit. .. Then, the drive voltage can be applied to the detection piezoelectric units C1 and D1 by the control of the drive control unit. As a result, when the drive control unit detects an abnormality in the first actuator, the drive control unit applies a voltage to the detection piezoelectric units C1 and D1 of the second actuator to move the mirror unit M and perform optical scanning. .. Therefore, it is possible to prevent the laser beam from concentrating at one point in a predetermined region. When optical scanning is performed by the detection piezoelectric units C1 and D1, it is preferable to project an image indicating that an abnormality has occurred. As a result, even when the light from the light source cannot be deflected to the outside of the predetermined region by the detection piezoelectric units C1 and D1, it is possible to prevent the light from being concentrated on one point by scanning the light and to project an image showing an abnormality. Allows the user to notice the anomaly.

In an actuator in which a plurality of beam portions 3A are connected in a serpentine manner by a folded-back portion 3R as in the optical deflector 1 of a further modified example shown in FIG. 17, the driving piezoelectric portions A1 and A2 are connected to each beam portion 3A. , ..., B1, B2, ... And the detection piezoelectric portions C1, C2, ..., D1, D2, ... May be provided in parallel to perform the same operation as described above.

1 Optical deflector 3 Elastic part (second elastic part, second actuator)
A1, A2 Drive piezoelectric part (second drive part, second actuator)
4 Elastic part (second elastic part, second actuator)
5A, 5B base (movable support)
6A, 6B Mirror support (first elastic part, first actuator)
B1, B2 Drive piezoelectric part (second drive part, second actuator)
A3, B3 Piezoelectric part for forced drive (forced drive part, third actuator)
A4, B4 drive piezoelectric part (first drive part, first actuator)
C1, C2 detection piezoelectric part (piezoelectric drive part, second actuator)
Piezoelectric part for D1 and D2 detection (piezoelectric drive part, second actuator)
M Mirror unit 12 Laser light source 16 Optical scanning drive control unit (drive control unit)
50 Current detection unit (first abnormality detection unit)
51-54 current detection unit (second abnormality detection unit)
80 Drive control unit 90 Reinforcing rib (reinforcing member)
100,200 head-up display device (image projection device)
120 Photodetector 311 Imaging optical system 312 Scanning optical system 600 Object recognition device 605 Photodetector 610 Photodetector 703a to 703d Receiver (photodetector, first and second abnormality detectors)
1000 Optical writing unit 1021 Imaging optical system 1022 Optical deflector 1300 Image forming apparatus 1302 Photoreceptor drum (photoreceptor, surface to be scanned)

Japanese Unexamined Patent Publication No. 2013-173465

Claims (9)

A mirror part with a reflective surface and
A plurality of actuators that drive the mirror unit around a predetermined axis,
A drive control unit that controls the drive of the plurality of actuators,
An optical deflection device including an abnormality detection unit for detecting an abnormality in at least one of the plurality of actuators.
When the abnormality detection unit does not detect an abnormality, the light deflector deflects the light to a predetermined range.
The actuator has a first actuator that drives the mirror portion around the first axis and a second actuator that drives the mirror portion around the second axis.
The abnormality detection unit includes a first abnormality detection unit that detects an abnormality of the first actuator and a second abnormality detection unit that detects an abnormality of the second actuator.
When the drive control unit detects an abnormality in one of the first actuator or the second actuator by the first abnormality detecting unit or the second abnormality detecting unit, the drive control unit uses the other actuator to obtain the abnormality. An optical deflector that controls a light beam incident on a mirror unit so as to deflect it out of a predetermined range different from the predetermined range. The light deflection device according to claim 1.
The drive control unit includes a first drive power supply unit that applies a drive voltage to the first actuator, and a second drive power supply unit that applies a drive voltage to the second actuator.
The first abnormality detection unit detects an abnormality by detecting a current between the first actuator and the first drive power supply unit.
The second abnormality detection unit is an optical deflection device that detects an abnormality by detecting a current between the second actuator and the second drive power supply unit. The light deflector according to claim 1 or 2.
A mirror support portion that supports the mirror portion and
A movable support portion for supporting the first actuator is provided.
The mirror portion is connected to the first actuator via the mirror support portion.
The second actuator is connected to the first actuator via the movable support portion, and is connected to the first actuator.
The first actuator has a first elastic portion connected to the mirror support portion and a first drive portion that elastically deforms the first elastic portion.
The second actuator is an optical deflector having a second elastic portion connected to the movable support portion and a second drive portion that elastically deforms the second elastic portion. The light deflection device according to claim 3.
The second elastic portion is formed by connecting a plurality of beam portions in a meandering manner.
The second drive unit has a plurality of piezoelectric drive units individually provided on the plurality of beam portions.
The drive control unit controls the drive by applying different drive voltages to the two piezoelectric drive units individually provided on the two adjacent beams.
The second abnormality detecting unit detects a current between the two piezoelectric drive units individually provided on the two adjacent beams and the drive control unit, and detects an abnormality in each of the piezoelectric drive units. Light deflection device. The light deflector according to any one of claims 1 to 4 and a light source unit that emits light are provided.
An image projection device that projects an image formed by light scanning light from the light source unit with the light deflector. The image projection device according to claim 5.
When the first abnormality detecting unit or the second abnormality detecting unit detects an abnormality, the drive control unit deflects the light flux incident on the mirror unit to a region outside the scanning region projected as an image. Image projection device. The image projection device according to claim 5.
It is provided outside the area through which the light in the scanning area projected as an image passes, and is provided with a photodetector that detects the light.
The drive control unit is an image projection device that deflects a light flux incident on the mirror unit to the light detection unit when the first abnormality detection unit or the second abnormality detection unit detects an abnormality. A light comprising the light deflecting device according to any one of claims 1 to 4 and an imaging optical system that forms a spot-like image of the reflected light scanned by the light deflecting device on a surface to be scanned. Write unit. The photodetector comprising the light deflector according to any one of claims 1 to 4 for scanning a measured luminous flux toward an object and a photodetector for receiving the reflected light from the object. An object recognition device characterized by recognizing an object based on the light received by the device.

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