JP2021071582A - Light deflector, image projection device, head-up display, laser head lamp, head-mounted display, object recognition device, and vehicle - Google Patents

Abstract

To provide a light deflector that can increase the accuracy in detecting the angle of oscillation of the light deflector.SOLUTION: A light deflector comprises: a reflection part that includes a reflection surface for reflecting light; support parts that are connected with the reflection part at one ends; a stationary part that is connected with the other ends of the support parts; piezoelectric members that deform the support parts to oscillate the reflection part; a frequency detection part that detects the frequency of a driving signal input to the piezoelectric members; a displacement amount detection part that detects the amount of displacement of the piezoelectric members; and an operation part that calculates the angle of oscillation of the reflection part based at least on frequency information on the frequency detected by the frequency detection part and displacement amount information on the amount of displacement detected by the displacement amount detection part.SELECTED DRAWING: Figure 16

Description

The present invention relates to a light deflector, an image projection device, a head-up display, a laser headlamp, a head-mounted display, an object recognition device, and a vehicle.

In recent years, a light deflector realized by MEMS (Micro Electro Mechanical Systems) technology as a small optical scanning means mounted on an image display device represented by a projector and a sensing device represented by LiDAR (Light Detection And Ranging). Development is active, and practical application has begun for some applications. Optical deflectors used in these applications are required to have a mirror diameter of 1 mm or more and a mirror runout angle of 10 degrees or more, and both the mirror size and the runout angle tend to increase as compared with conventional optical deflectors for optical communication. Is generally known.

Further, in order to correctly acquire the optical deflection angle in optical scanning and control the projection timing of LiDAR and the drive of the optical deflector, a piezoelectric sensor is provided in parallel with the piezoelectric actuator of the optical deflector, and the output signal is used as the source. A method of detecting the angle of a light deflector is generally known.

Further, for the purpose of completely matching the signal acquired by the piezoelectric sensor with the displacement amount of the piezoelectric actuator, the angle correction data measured in advance is stored in the storage circuit as a table, and the mirror swings to the maximum positive angle. A configuration is disclosed in which the maximum mirror runout angle is calculated by adding a correction to the value obtained at times, and the control is controlled to a desired runout angle. (See, for example, Patent Document 1)

However, in the conventional detection method using a piezoelectric sensor, the response of the piezoelectric actuator to the swing angle, which is the swing angle of the optical deflector, is not constant because it is affected by the drive amplitude and temperature of the optical deflector and the drive frequency. Therefore, the deflection angle of the optical deflector obtained even if the output has the same amplitude is not accurate, and there is room for improvement in improving the accuracy in calculating the mirror deflection angle in the optical deflector. That is, there has been a demand for an optical deflector having high swing angle detection accuracy.

The optical deflector according to one aspect of the disclosed technique includes a reflecting portion having a reflecting surface that reflects light, a supporting portion connected to the reflecting portion at one end, and a fixed portion connected to the other end of the supporting portion. A piezoelectric member that deforms the support portion to swing the reflective portion, a frequency detection unit that detects the frequency of a drive signal input to the piezoelectric member, and a displacement that detects the amount of displacement of the piezoelectric member. The reflection unit has an amount detection unit, and is based on at least the frequency information of the frequency detected by the frequency detection unit and the displacement amount information of the displacement amount detected by the displacement amount detection unit. It is characterized by having a calculation unit for calculating the swing angle.

According to the disclosed technique, it is possible to improve the detection accuracy of the swing angle of the optical deflector.

It is the schematic of an example of an optical scanning system. It is a hardware block diagram of an example of an optical scanning system. It is a functional block diagram of an example of a control device. It is a flowchart of an example of the process which concerns on an optical scanning system. It is a schematic diagram of an example of an automobile equipped with a head-up display device. It is a schematic diagram of an example of a head-up display device. It is a schematic diagram of an example of an image forming apparatus equipped with an optical writing apparatus. It is the schematic of an example of an optical writing apparatus. It is a schematic diagram of an example of an automobile equipped with a rider device. It is the schematic of an example of a rider device. It is the schematic explaining an example of the structure of a laser light source. It is the schematic explaining an example of the structure of a laser headlamp. It is a schematic perspective view which shows an example of the structure of the head-mounted display. It is a figure which shows an example of a part of the structure of a head-mounted display. It is the schematic which shows an example of the packaged movable device. It is a block diagram of the light deflector in 1st Embodiment. It is a block diagram of the movable device (1) in 1st Embodiment. It is a block diagram of the movable device (2) in 1st Embodiment. It is a block diagram of the movable device (3) in 1st Embodiment. It is a block diagram of the movable device (4) in 1st Embodiment. It is explanatory drawing of the light deflector in 1st Embodiment. It is a block diagram of the light deflector in 2nd Embodiment. It is a block diagram of the light deflector in 3rd Embodiment. It is a block diagram of the light deflector in 4th Embodiment. It is a block diagram of the movable device in 5th Embodiment. It is sectional drawing of the movable device in 5th Embodiment. It is a block diagram of another movable device in 5th Embodiment.

Hereinafter, embodiments of the present invention will be described in detail. The same members and the like are designated by the same reference numerals and the description thereof will be omitted.

[Optical scanning system]
First, the optical scanning system to which the movable device of the present embodiment is applied will be described in detail with reference to FIGS. 1 to 4.

FIG. 1 shows a schematic diagram of an example of an optical scanning system. As shown in FIG. 1, the optical scanning system 10 is a system in which the light emitted from the light source device 12 is deflected by the reflecting surface 14 included in the movable device 13 under the control of the control device 11 to lightly scan the scanned surface 15. is there.

The optical scanning system 10 includes a control device 11, a light source device 12, and a movable device 13 having a reflecting surface 14.

The control device 11 is an electronic circuit unit including, for example, a CPU (Central Processing Unit) and an FPGA (Field-Programmable Gate Array). The movable device 13 is, for example, a MEMS (Micro Electromechanical Systems) device having a reflecting surface 14 and capable of moving the reflecting surface 14. The light source device 12 is, for example, a laser device that irradiates a laser. The surface to be scanned 15 is, for example, a screen.

The control device 11 generates a control command for the light source device 12 and the movable device 13 based on the acquired optical scanning information, and outputs a drive signal to the light source device 12 and the movable device 13 based on the control command.

The light source device 12 irradiates the light source based on the input drive signal. The movable device 13 moves the reflecting surface 14 in at least one of the uniaxial direction and the biaxial direction based on the input drive signal.

As a result, for example, by controlling the control device 11 based on the image information which is an example of the optical scanning information, the reflecting surface 14 of the movable device 13 is reciprocated in a predetermined range in the biaxial direction and is incident on the reflecting surface 14. An arbitrary image can be projected on the surface to be scanned 15 by deflecting the irradiation light from the light source device 12 around a certain axis and scanning the light. The details of the movable device of this embodiment and the details of control by the control device will be described later.

Next, the hardware configuration of an example of the optical scanning system 10 will be described with reference to FIG. FIG. 2 is a hardware configuration diagram of an example of the optical scanning system 10. As shown in FIG. 2, the optical scanning system 10 includes a control device 11, a light source device 12, and a movable device 13, each of which is electrically connected. Of these, the control device 11 includes a CPU 20, a RAM 21 (Random Access Memory), a ROM 22 (Read Only Memory), an FPGA 23, an external I / F 24, a light source device driver 25, and a movable device driver 26.

The CPU 20 is an arithmetic unit that reads programs and data from a storage device such as the ROM 22 onto the RAM 21 and executes processing to realize overall control and functions of the control device 11.

The RAM 21 is a volatile storage device that temporarily holds programs and data.

The ROM 22 is a non-volatile storage device capable of holding programs and data even when the power is turned off, and stores processing programs and data executed by the CPU 20 to control each function of the optical scanning system 10. There is.

The FPGA 23 is a circuit that outputs a control signal suitable for the light source device driver 25 and the movable device driver 26 according to the processing of the CPU 20.

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

The light source device driver 25 is an electric circuit that outputs a drive signal such as a drive voltage to the light source device 12 according to an input control signal.

The movable device driver 26 is an electric circuit that outputs a drive signal such as a drive voltage to the movable device 13 according to an input control signal.

In the control device 11, the CPU 20 acquires optical scanning information from the external device or network via the external I / F 24. The configuration may be such that the CPU 20 can acquire the optical scanning information, and the optical scanning information may be stored in the ROM 22 or FPGA 23 in the control device 11, or the SSD or the like may be newly stored in the control device 11. A storage device may be provided and the optical scanning information may be stored in the storage device.

Here, the optical scanning information is information indicating how the surface to be scanned 15 is optical-scanned. For example, when displaying an image by optical scanning, the optical scanning information is image data. Further, for example, when optical writing is performed by optical scanning, the optical scanning information is write data indicating the writing order and the writing location. In addition, for example, when object recognition is performed by optical scanning, the optical scanning information is irradiation data indicating the timing and irradiation range of irradiating the light for object recognition.

The control device 11 can realize the functional configuration described below by the instruction of the CPU 20 and the hardware configuration shown in FIG.

Next, the functional configuration of the control device 11 of the optical scanning system 10 will be described with reference to FIG. FIG. 3 is a functional block diagram of an example of a control device for an optical scanning system.

As shown in FIG. 3, the control device 11 has a control unit 30 and a drive signal output unit 31 as functions.

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

The drive signal is a signal for controlling the drive of the light source device 12 or the movable device 13. For example, in the light source device 12, it is a drive voltage that controls the irradiation timing and irradiation intensity of the light source. Further, for example, in the movable device 13, it is a drive voltage that controls the timing and the movable range of moving the reflective surface 14 included in the movable device 13.

Next, the process of optical scanning the surface to be scanned 15 by the optical scanning system 10 will be described with reference to FIG. FIG. 4 is a flowchart of an example of processing related to the optical scanning system.

In step S11, the control unit 30 acquires optical scanning information from an external device or the like.

In step S12, the control unit 30 generates a control signal from the acquired optical scanning information and outputs the control signal to the drive signal output unit 31.

In step S13, the drive signal output unit 31 outputs a drive signal to the light source device 12 and the movable device 13 based on the input control signal.

In step 14, the light source device 12 irradiates light based on the input drive signal. Further, the movable device 13 moves the reflecting surface 14 based on the input drive signal. By driving the light source device 12 and the movable device 13, light is deflected in an arbitrary direction and light-scanned.

In the optical scanning system 10, one control device 11 has a device and a function of controlling the light source device 12 and the movable device 13, but the control device for the light source device and the control device for the movable device It may be provided separately.

Further, in the optical scanning system 10, one control device 11 is provided with a function of a control unit 30 of a light source device 12 and a movable device 13 and a function of a drive signal output unit 31, but these functions exist as separate bodies. For example, a drive signal output device having a drive signal output unit 31 may be provided separately from the control device 11 having the control unit 30. In the optical scanning system 10, a movable device 13 having a reflecting surface 14 and a control device 11 may form an optical deflection system that performs optical deflection.

[Image projection device]
Next, the image projection device to which the movable device of the present embodiment is applied will be described in detail with reference to FIGS. 5 and 6.

FIG. 5 is a schematic view of an embodiment of an automobile 400 equipped with a head-up display device 500, which is an example of an image projection device. Further, FIG. 6 is a schematic view of an example of the head-up display device 500.

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

As shown in FIG. 5, the head-up display device 500 is installed near, for example, a windshield (windshield 401, etc.) of an automobile 400. The projected light L emitted from the head-up display device 500 is reflected by the windshield 401 and heads toward the observer (driver 402) who is the user. As a result, the driver 402 can visually recognize the image or the like projected by the head-up display device 500 as a virtual image. A combiner may be installed on the inner wall surface of the windshield so that the user can visually recognize the virtual image by the projected light reflected by the combiner.

As shown in FIG. 6, the head-up display device 500 emits laser light from red, green, and blue laser light sources 501R, 501G, and 501B. The emitted laser light passes through an incident optical system composed of collimating lenses 502, 503, 504 provided for each laser light source, two dichroic mirrors 505, 506, and a light amount adjusting unit 507. It is deflected by the movable device 13 having the reflecting surface 14. Then, the deflected laser beam is projected onto the screen via a projection optical system including a free-form surface mirror 509, an intermediate screen 510, and a projection mirror 511. In the head-up display device 500, the laser light sources 501R, 501G, 501B, the collimating lenses 502, 503, 504, and the dichroic mirrors 505 and 506 are unitized by an optical housing as a light source unit 530.

The head-up display device 500 projects the intermediate image displayed on the intermediate screen 510 onto the windshield 401 of the automobile 400, so that the driver 402 visually recognizes the intermediate image as a virtual image.

The laser light of each color emitted from the laser light sources 501R, 501G, and 501B is made substantially parallel light by the collimated lenses 502, 503, and 504, and is synthesized by the two dichroic mirrors 505 and 506, which are the compositing units. The combined laser light is two-dimensionally scanned by the movable device 13 having the reflecting surface 14 after the light amount is adjusted by the light amount adjusting unit 507. The projected light L two-dimensionally scanned by the movable device 13 is reflected by the free-form surface mirror 509, corrected for distortion, and then condensed on the intermediate screen 510 to display an intermediate image. The intermediate screen 510 is composed of a microlens array in which microlenses are two-dimensionally arranged, and magnifies the projected light L incident on the intermediate screen 510 in microlens units.

The movable device 13 reciprocates the reflecting surface 14 in the biaxial direction, and two-dimensionally scans the projected light L incident on the reflecting surface 14. The drive control of the movable device 13 is performed in synchronization with the light emission timing of the laser light sources 501R, 501G, and 501B.

The head-up display device 500 as an example of the image projection device has been described above, but the image projection device may be a device that projects an image by performing optical scanning by a movable device 13 having a reflecting surface 14. .. For example, it is mounted on a projector that is placed on a desk or the like and projects an image on a display screen, or is mounted on a mounting member that is mounted on an observer's head or the like, and is projected onto a reflection / transmission screen of the mounting member, or the eyeball is used as a screen. The same can be applied to a head-mounted display device or the like that projects an image.

Further, the image projection device is not only a vehicle or a mounting member, but also a moving body such as an aircraft, a ship, or a mobile robot, or a work robot that operates a drive target such as a manipulator without moving from the place. It may be mounted on a non-moving body.

The head-up display device 500 is an example of the "head-up display" described in the claims. The automobile 400 is an example of the "vehicle" described in the claims.

[Optical writing device]
Next, the optical writing device to which the movable device 13 of the present embodiment is applied will be described in detail with reference to FIGS. 7 and 8.

FIG. 7 is an example of an image forming apparatus incorporating the optical writing apparatus 600. Further, FIG. 8 is a schematic view of an example of the optical writing device.

As shown in FIG. 7, the optical writing device 600 is used as a constituent member of an image forming device represented by a laser printer 650 or the like having a printer function using laser light. In the image forming apparatus, the optical writing device 600 performs optical writing on the photoconductor drum by lightly scanning the photoconductor drum which is the surface to be scanned 15 with one or a plurality of laser beams.

As shown in FIG. 8, in the optical writing device 600, the laser light from the light source device 12 such as a laser element passes through an imaging optical system 601 such as a collimating lens and then is transferred by a movable device 13 having a reflecting surface 14. It is deflected in the axial or biaxial direction. Then, the laser beam deflected by the movable device 13 passes through the scanning optical system 602 including the first lens 602a, the second lens 602b, and the reflection mirror portion 602c, and then passes through the surface to be scanned 15 (for example, a photoconductor drum or a photosensitive paper). ) Is irradiated and optical writing is performed. The scanning optical system 602 forms a spot-shaped light beam on the surface to be scanned 15. Further, the movable device 13 having the light source device 12 and the reflecting surface 14 is driven under the control of the control device 11.

As described above, the optical writing device 600 can be used as a constituent member of an image forming device having a printer function by laser light. Further, by making the scanning optical system different so that light scanning can be performed not only in the uniaxial direction but also in the biaxial direction, the laser beam is deflected to the thermal media to scan the light, and the laser label device for printing by heating and the like. It can be used as a constituent member of the image forming apparatus of.

Since the movable device 13 having the reflecting surface 14 applied to the optical writing device consumes less power for driving than the rotating multifaceted mirror using a polygon mirror or the like, the power saving of the optical writing device can be achieved. It is advantageous. Further, since the wind noise when the movable device 13 vibrates is smaller than that of the rotating multifaceted mirror, it is advantageous for improving the quietness of the optical writing device. The optical writing device requires an overwhelmingly smaller installation space than a rotating multifaceted mirror, and the amount of heat generated by the movable device 13 is also small, so that it is easy to miniaturize, which is advantageous for miniaturizing the image forming device. is there.

[Object recognition device]
Next, the object recognition device to which the movable device of the present embodiment is applied will be described in detail with reference to FIGS. 9 and 10.

FIG. 9 is a schematic view of an automobile equipped with a lidar (Laser Imaging Detection and Ranging) device, which is an example of an object recognition device. Further, FIG. 10 is a schematic view of an example of the rider device.

The object recognition device is a device that recognizes an object in the target direction, for example, a rider device.

As shown in FIG. 9, the rider device 700 is mounted on, for example, an automobile 701, and by light-scanning the target direction and receiving the reflected light from the object 702 existing in the target direction, the object 702 Recognize.

As shown in FIG. 10, the laser light emitted from the light source device 12 is reflected through an incident optical system composed of a collimating lens 703, which is an optical system in which divergent light is substantially parallel light, and a plane mirror 704. The movable device 13 having the surface 14 scans in one or two axial directions. Then, the object 702 in front of the apparatus is irradiated through the light projecting lens 705 or the like, which is a light projecting optical system. The drive of the light source device 12 and the movable device 13 is controlled by the control device 11. The reflected light reflected by the object 702 is photodetected by the photodetector 709. That is, the reflected light is received by the image pickup device 707 via the condenser lens 706 or the like which is an incident light detection and reception optical system, and the image pickup element 707 outputs the detection signal to the signal processing circuit 708. The signal processing circuit 708 performs predetermined processing such as binarization and noise processing on the input detection signal, and outputs the result to the distance measuring circuit 710.

FIG. 11 is a diagram showing a configuration example of a laser light source which is a light source device 12. The laser light source, which is the light source device 12, is formed of, for example, a VCSEL array 12A in which a plurality of laser element groups called "layers" are arranged in the same plane (surface emitting laser array). In the following description, the "surface emitting laser element" forming each layer of the laser light source which is the light source device 12 is abbreviated as "light emitting element". The VCSEL array 12A has layers 121-1 to 121-m, and each layer 121 has a plurality of light emitting elements 1221 to 122n (hereinafter, appropriately collectively referred to as "light emitting elements 122").

The light emitting element 122 is an element that can be integrated on the same substrate, and the optical axis of each light emitting element 122 is orthogonal to the arrangement surface of the VCSEL array 12A.

The light emission timing of each layer 121 is independently controlled by the light source device driver 25. Further, each layer 121 is controlled so that a plurality of light emitting elements 122 included in the layer 121 emit light at the same time.

In FIG. 11, a plurality of layers 121 are arranged one-dimensionally, but a VCSEL array 12A in which a plurality of layers 121 are arranged two-dimensionally may be used. The light emitting elements 122 of each layer 121 are arranged in a fine arrangement or in a honeycomb shape at a predetermined pitch, but the arrangement is not limited to this. The shape of the opening of the light emitting element 122 is not limited to a hexagon. The number of layers 121 of the VCSEL array 12A, the number of light emitting elements 122 in the layer 121, the size of the light emitting region, etc. are appropriately designed according to the angular resolution, scanning range, detection distance, etc. required for the rider device 700. ..

In the distance measuring circuit 710, the object is determined by the time difference between the timing when the light source device 12 emits the laser light and the timing when the laser light is received by the photodetector 709, or the phase difference for each pixel of the light receiving image sensor 707. The presence or absence of the 702 is recognized, and the distance information to the object 702 is calculated.

Since the movable device 13 having the reflecting surface 14 is less likely to be damaged and is smaller than the multifaceted mirror, it is possible to provide a compact radar device with high durability. Such a rider device can be attached to, for example, a vehicle, an aircraft, a ship, a robot, or the like, and can lightly scan a predetermined range to recognize the presence or absence of an obstacle and the distance to the obstacle.

FIG. 9 is a schematic view of an automobile 701 which is a moving body equipped with a rider device 700. The rider device 700 is attached to the upper part of the windshield of the automobile 701, the ceiling of the front seat, and the like. The rider device 700 recognizes the object 702 by light scanning, for example, in the traveling direction of the automobile 701 and receiving the reflected light from the object 702 existing in the traveling direction. The light projecting unit of the rider device 700, for example, suppresses the divergence angle of the laser beam in advance with an optical element such as MLA and scans the light, so that the light loss in the scanning unit of the movable device 13 or the like is reduced and the angle is high. Laser light can be projected far away with resolution.

The mounting position of the rider device 700 is not limited to the upper front of the automobile 701, and may be mounted on the side surface or the rear. The rider device 700 can be applied not only to vehicles but also to arbitrary moving objects such as aircraft, flying objects such as drones, and autonomous moving objects such as robots. By adopting the configuration of the light projecting unit 1 of the embodiment, the existence of an object and its position can be detected in a wide range.

In the above-mentioned object recognition device, the rider device 700 as an example has been described, but the object recognition device performs optical scanning by controlling the movable device 13 having the reflecting surface 14 by the control device 11, and uses a photodetector to perform optical scanning. The device may be any device that recognizes the object 702 by receiving the reflected light, and is not limited to the above-described embodiment.

For example, biometric authentication that recognizes an object by calculating object information such as shape from distance information obtained by light scanning the hand or face and referring to it as a record, or recognizing an intruder by light scanning the target range. It can also be applied to a security sensor, a component of a three-dimensional scanner that calculates and recognizes object information such as a shape from distance information obtained by optical scanning, and outputs it as three-dimensional data.

[Laser headlamp]
Next, the laser headlamp 50 in which the movable device of the present embodiment is applied to the headlight of an automobile will be described with reference to FIG. FIG. 12 is a schematic view illustrating an example of the configuration of the laser headlamp 50.

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

The light source device 12b is a light source that emits a blue laser beam. The light emitted from the light source device 12b enters the movable device 13 and is reflected by the reflecting surface 14. The movable device 13 moves the reflecting surface in the XY directions based on the signal from the control device 11, and two-dimensionally scans the blue laser light from the light source device 12b in the XY directions.

The scanning light from the movable device 13 is reflected by the mirror 51 and incident on the transparent plate 52. The front surface or the back surface of the transparent plate 52 is covered with a yellow phosphor. The blue laser beam from the mirror 51 changes to white within the legal range of the headlight color as it passes through the yellow phosphor coating on the transparent plate 52. As a result, the front of the automobile is illuminated with white light from the transparent plate 52.

The scanning light from the movable device 13 scatters in a predetermined manner when passing through the phosphor of the transparent plate 52. This alleviates the glare of the illuminated object in front of the vehicle.

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

[Head-mounted display]
Next, the head-mounted display 60 to which the movable device of the present embodiment is applied will be described with reference to FIGS. 13 to 14. Here, the head-mounted display 60 is a head-mounted display that can be worn on a human head, and can have a shape similar to, for example, eyeglasses. The head-mounted display will be abbreviated as HMD below.

FIG. 13 is a perspective view illustrating the appearance of the HMD 60. In FIG. 13, the HMD 60 is composed of a front 60a and a temple 60b provided in pairs on the left and right in a substantially symmetrical manner. The front 60a can be configured by, for example, a light guide plate 61, and an optical system, a control device, and the like can be built in the temple 60b.

FIG. 14 is a diagram partially illustrating the configuration of the HMD 60. Although the configuration for the left eye is illustrated in FIG. 14, the HMD 60 has the same configuration for the right eye.

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

As described above, the light source unit 530 is a unitization of the laser light sources 501R, 501G, and 501B, the collimating lenses 502, 503, and 504, and the dichroic mirrors 505 and 506 by an optical housing. In the light source unit 530, the three-color laser beams from the laser light sources 501R, 501G, and 501B are combined by the dichroic mirrors 505 and 506, which are the compositing units. The combined parallel light is emitted from the light source unit 530.

The light from the light source unit 530 is incident on the movable device 13 after the light amount is adjusted by the light amount adjusting unit 507. The movable device 13 moves the reflecting surface 14 in the XY directions based on the signal from the control device 11, and two-dimensionally scans the light from the light source unit 530. The drive control of the movable device 13 is performed in synchronization with the light emission timing of the laser light sources 501R, 501G, and 501B, and a color image is formed by the scanning light.

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

The half mirror 62 reflects the light from the light guide plate 61 toward the back surface of the HMD 60 and emits the light toward the eyes of the wearer 63 of the HMD 60. The half mirror 62 has, for example, a free curved surface shape. The image obtained by the scanning light is imaged on the retina of the wearer 63 by reflection by the half mirror 62. Alternatively, an image is formed on the retina of the wearer 63 by the reflection by the half mirror 62 and the lens effect of the crystalline lens on the eyeball. Further, the spatial distortion of the image is corrected by the reflection by the half mirror 62. The wearer 63 can observe the image formed by the light scanned in the XY directions.

Since 62 is a half mirror, the image of the light from the outside world and the image of the scanning light are superimposed and observed on the wearer 63. By providing a mirror instead of the half mirror 62, the light from the outside world may be eliminated and only the image by the scanning light can be observed.

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

FIG. 15 is a schematic view of an example of a packaged mobile device.

As shown in FIG. 15, the movable device 13 is attached to the attachment member 802 arranged inside the package member 801 and is packaged by covering a part of the package member 801 with the transmission member 803 and sealing the package member 801. Will be done. Further, the package is sealed with an inert gas such as nitrogen. As a result, deterioration of the movable device 13 due to oxidation is suppressed, and durability against changes in the environment such as temperature is further improved.

Details of the movable device of the present embodiment used for the light deflection system, the light scanning system, the image projection device, the light writing device, the object recognition device, the laser head lamp, and the head-mounted display described above are described in the drawings below. Will be explained with reference to. In each drawing, the same components may be designated by the same reference numerals, and duplicate description may be omitted.

In the description of the embodiment, the optical scan with the first axis as the center of rotation is the sub-scan, and the optical scan with the second axis as the center of rotation is the main scan. Further, it is assumed that rotation, rocking, and movement in the terms of the embodiment are synonymous. Further, among the directions indicated by the arrows, the X direction is a direction parallel to the first axis, the Y direction is a direction parallel to the second axis, and the Z direction is a direction orthogonal to the XY plane. The Z direction is an example of the "stacking direction".

[First Embodiment]
The light deflector in the first embodiment will be described with reference to FIG. The optical deflector 201 in this embodiment includes a movable device 13, a drive circuit 221 and a displacement amount detection unit 222, a temperature detection unit 223, an amplitude detection unit 224, a frequency detection unit 225, and a calculation unit 226. Since the drive circuit 221 generates a drive signal for driving the piezoelectric actuator 103, it may be referred to as a drive signal generation unit.

FIG. 17 shows the structure of the movable device 13 in this embodiment. The movable device 13 in the present embodiment has a movable mirror portion 101 having a reflecting surface 14 that reflects light, a spring portion 102 of a torsion bar, a piezoelectric actuator 103 that generates a driving force, and a piezoelectric that detects a twist of the spring portion 102. It has a sensor 104, a frame-shaped fixing portion 105, and the like. The piezoelectric actuator 103 and the piezoelectric sensor 104 are provided on the surface of the cantilever portion 106, and the piezoelectric actuator 103 and the piezoelectric sensor 104 are arranged in parallel. In the present application, the mirror portion 101 may be referred to as a reflecting portion.

More specifically, spring portions 102 connected to the mirror portion 101 are provided on both sides of the mirror portion 101 in the −X direction and the + X direction, respectively. Each spring portion 102 is formed long in the X direction, one end of each spring portion 102 is connected to the mirror portion 101, and the other end is connected to the cantilever portion 106. There is. Each cantilever portion 106 is formed long in the Y direction, and the other end portion of the spring portion 102 is connected to the central portion of the cantilever portion 106. The cantilever portion 106 is connected to the frame-shaped fixing portion 105 at both ends in the Y direction.

Therefore, the mirror portion 101 is supported by the support portion 107 formed by the spring portion 102 and the cantilever portion 106. In the present embodiment, by applying a voltage to the piezoelectric actuator 103 provided on the surface of the cantilever portion 106, the cantilever portion 106 vibrates, and this vibration is converted into the twist of the spring portion 102 to rotate the mirror portion 101. It rotates around the first axis, which is the driving axis.

That is, in the movable device 13 in the present embodiment, the mirror unit 101 can be swung by receiving the drive signal input from the drive circuit 221. Here, the drive signal is a sine wave, and by setting the frequency of the drive signal to a frequency close to the inherent resonance frequency f0 in the spring portion 102 of the movable device 13, the deflection angle of the mirror portion 101 in the movable device 13 is increased. can do. In the present application, the runout angle may be referred to as a swing angle.

Therefore, when a force is generated in the piezoelectric actuator 103 by the drive signal input from the drive circuit 221 and the spring portion 102 is deformed, a detection signal is output from the piezoelectric sensor 104. The detection signal is a signal indicating the deflection angle of the mirror unit 101. The displacement amount detection unit 222 detects the signal strength of this detection signal. At this time, if the signal strength of the detection signal is strong, it represents a state in which the runout angle of the mirror portion 101 is large, and if it is weak, it represents a state in which the runout angle of the mirror portion 101 is small.

Further, the temperature detection unit 223 is arranged in the vicinity of the movable device 13 and detects the ambient temperature of the piezoelectric actuator 103 in the movable device 13. The amplitude detection unit 224 detects the drive amplitude of the drive signal input to the piezoelectric actuator 103. The frequency detection unit 225 detects the drive frequency of the drive signal input to the piezoelectric actuator 103.

The calculation unit 226 includes an ambient temperature (T) which is temperature information detected by the temperature detection unit 223, an amplitude detection unit 224, and a frequency detection unit 225, a drive amplitude (A) which is drive amplitude information, and a drive frequency which is drive frequency information. From (f), an appropriate correction coefficient c (T, A, f) is calculated. Further, the correction coefficient c (T, A, f) is multiplied by the output of the displacement amount detection unit 222. As a result, the error between the output signal of the piezoelectric sensor 104 and the actual runout angle of the mirror unit 101 is corrected and output as runout angle information. In the present embodiment, more accurate correction can be performed by including the drive frequency detected by the frequency detection unit 225. The correction coefficient c (T, A, f) is calculated by, for example, an operation using a polynomial of a linear function of temperature (T), drive amplitude (A), and drive frequency (f) as shown in Equation 1 below. It may be calculated, but this is not always the case. For example, it may be calculated by calculation using a non-linear function of ambient temperature (T), drive amplitude (A), and drive frequency (f). Note that a0, a1 and a2 are coefficients, and a3 is a constant.

固定部１０５は、図１７に示されるように、枠状に一体で形成されたものであってもよいが、図１８に示されるように、固定部１０５の一部に開口部１０５ａを設けることにより、固定部１０５が分離されているものであってもよい。ミラー部１０１が設けられている部分において、第１軸に対して直交する方向、即ち、±Ｙ方向に、開口部１０５ａを設けることにより、ミラー部１０１において反射された光が、枠状の固定部１０５により遮断されることを防ぐことができる。

As shown in FIG. 17, the fixing portion 105 may be integrally formed in a frame shape, but as shown in FIG. 18, an opening 105a is provided in a part of the fixing portion 105. Therefore, the fixing portion 105 may be separated. By providing the opening 105a in the direction orthogonal to the first axis, that is, in the ± Y direction in the portion where the mirror portion 101 is provided, the light reflected by the mirror portion 101 is fixed in a frame shape. It is possible to prevent the block from being blocked by the unit 105.

Further, as shown in FIG. 19, the movable device may have a folded-back spring structure in which a plurality of cantilever portions 109 are formed in a meander shape in the support portion 108 that supports the mirror portion 101. Each cantilever portion 109 is formed long in the Y direction, and a piezoelectric actuator 103 and a piezoelectric sensor 104 are provided on the surface of each cantilever portion 109. Further, the connection position between the mirror portion 101 and the support portion 108 of the folded spring structure and the connection position between the support portion 108 and the fixed portion 105 are not limited to the positions shown in FIG. You may.

FIG. 20 shows a movable device shown in FIG. 19 having a structure in which an opening 105a is provided in the fixing portion 105 and the fixing portion 105 is separated, as in the case of FIG.

Next, the deflection angle of the mirror portion 101 of the optical deflector and the maximum value of the output of the piezoelectric sensor 104 in the present embodiment will be described.

FIG. 21 shows the frequency characteristic of the mirror runout angle (mirror runout angle characteristic) of the mirror unit 101 in the vicinity of the resonance frequency f0 of the movable device 13 and the piezoelectric sensor detected by the displacement amount detection unit 222 in the optical deflector of the present embodiment. The frequency characteristic (detection signal characteristic) of the output of 104 is shown. Each signal is standardized by the value at the resonance frequency f0.

The runout angle of the mirror unit 101 and the detection output of the piezoelectric sensor 104 are preferably in a proportional relationship, and the mirror runout angle characteristic and the detection signal characteristic are preferably overlapped without being affected by the frequency. However, when actually measured, as shown in FIG. 21, there is a discrepancy between the mirror runout angle characteristic and the detection signal characteristic. One of the causes is considered to be that signal attenuation occurs on the high frequency side due to the supply of the drive signal to the piezoelectric actuator 103, the parasitic resistance in the output signal from the piezoelectric sensor 104, and the parasitic capacitance. Therefore, in such a state, even if the runout angle of the mirror unit 101 is the same, the output of the piezoelectric sensor 104 shows a different value depending on the frequency, so that the runout angle of the mirror part 101 of the movable device must be accurately grasped. I can't.

In the optical deflector of the present embodiment, the frequency detection unit 225 is provided, and the calculation unit 226 performs correction including the frequency information obtained by the frequency detection unit 225, whereby the deflection angle of the mirror unit 101 of the movable device 13 is adjusted. Can be obtained accurately. As a result, the state of the light deflector can be accurately grasped.

From the above, in the optical deflector of the first embodiment, the mirror portion 101 having the reflecting surface 14, the fixed portion 105 around the mirror portion 101, one end is connected to the mirror portion 101, and the other end is the fixed portion 105. It is connected to the. A support portion 107 or the like that supports the mirror portion 101, and a piezoelectric actuator 103 that swings the mirror portion 101 with respect to the fixed portion 105 about a predetermined rotation axis by piezoelectric drive. It has a piezoelectric sensor 104 which is arranged around the piezoelectric actuator 103 and serves as a detection unit for detecting the displacement amount of the piezoelectric actuator 103, and a temperature detection unit 223 for measuring the ambient temperature of the piezoelectric actuator 103. It has an amplitude detection unit 224 for detecting the drive amplitude of the piezoelectric actuator drive signal and a frequency detection unit 225 for detecting the drive frequency of the piezoelectric actuator drive signal. It has a calculation unit 226 that calculates the deflection angle of the mirror unit 101 based on the displacement amount information, the temperature information, the amplitude information of the piezoelectric drive signal, and the frequency information. As a result, in the optical deflector of the present embodiment, the output signal of the piezoelectric sensor 104 can be corrected based on the correction coefficient calculated from the drive amplitude, the drive frequency, and the ambient temperature. Therefore, it is possible to accurately calculate the deflection angle of the mirror portion 101 of the optical deflector from the output of the piezoelectric sensor 104 and accurately grasp the state of the optical deflector.

[Second Embodiment]
Next, the light deflector in the second embodiment will be described with reference to FIG. The optical deflector 202 in this embodiment includes a movable device 13, a drive circuit 221 and a displacement amount detection unit 222, a temperature detection unit 223, a calculation unit 226, an amplitude information acquisition unit 227, and a frequency information acquisition unit 228.

The amplitude information acquisition unit 227 acquires the amplitude information of the drive signal generated by the drive circuit 221, that is, the amplitude information from the drive circuit 221 and outputs the correction coefficient to the calculation unit 226 based on the information. Further, the frequency information acquisition unit 228 acquires the frequency information of the drive signal generated by the drive circuit 221, that is, the frequency information from the drive circuit 221 and outputs the correction coefficient to the calculation unit 226 based on the information.

Both the amplitude information acquisition unit 227 and the frequency information acquisition unit 228 do not need to detect the value from the drive signal itself, and calculate the correction coefficient by inputting each set value from the drive circuit 221. The calculation unit 226 calculates an appropriate correction coefficient based on the information input from the amplitude information acquisition unit 227, the frequency information acquisition unit 228, and the temperature detection unit 223, and multiplies the output of the displacement amount detection unit 222. As a result, the error between the output signal of the piezoelectric actuator 103 and the actual runout angle of the mirror unit 101 is corrected.

The movable device 13, the displacement amount detection unit 222, and the temperature detection unit 223 in this embodiment are the same as those in the first embodiment.

From the above, in the second embodiment, the mirror portion 101 having the reflecting surface 14, one or two fixing portions 105 supporting the mirror portion 101, one end to the mirror portion 101, and the other end to the fixing portion 105. It has a connected support portion 107. Further, a detection unit is provided with a piezoelectric actuator 103 that swings the mirror portion 101 with respect to the fixed portion 105 about a predetermined axis by piezoelectric drive, and is arranged around the piezoelectric actuator 103 to detect the displacement amount of the piezoelectric actuator 103. It has a piezoelectric sensor 104 and the like. It has a temperature detection unit 223 for measuring the ambient temperature of the piezoelectric actuator 103, an amplitude information acquisition unit 227 for acquiring amplitude information from the drive circuit 221 and a frequency information acquisition unit 228 for acquiring frequency information from the drive circuit 221. It has a calculation unit 226 that calculates the deflection angle of the mirror unit 101 based on the displacement amount information, the temperature information, the amplitude information of the piezoelectric drive signal, and the frequency information. As a result, in the optical deflector of the present embodiment, the output signal of the piezoelectric sensor 104 can be corrected based on the correction coefficient calculated from the amplitude, frequency, and ambient temperature of the drive signal. Therefore, even if there is an influence of the drive frequency, the deflection angle of the mirror unit 101 can be accurately calculated from the output of the piezoelectric sensor 104, and the state of the optical deflector 202 can be acquired more accurately. In the present embodiment, the amplitude and frequency information of the drive signal is not detected from the drive signal itself, but is acquired from the setting information, so that the correction can be performed accurately with a simple circuit.

[Third Embodiment]
Next, the optical deflector 203 in the third embodiment will be described with reference to FIG. 23. The optical deflector 203 in the present embodiment includes a movable device 13, a drive circuit 221 and a displacement amount detection unit 222, a temperature detection unit 223, an amplitude detection unit 224, a frequency detection unit 225, a calculation unit 226, and a drive amplitude control unit 229. Have.

The drive amplitude control unit 229 compares the runout angle set value of the mirror unit 101 input from the outside with the maximum runout angle value obtained from the runout angle information of the mirror unit 101 calculated by the calculation unit 226. Then, the amplitude of the drive circuit 221 is changed so that the runout angle of the mirror unit 101 becomes equal to the mirror runout angle set value, and the runout angle of the mirror unit 101 is controlled. For control, a method such as PID (Proportional-Integral-Differential) control is generally known. PID control is a method of controlling an input value by three elements: a deviation between an output value and a target value, an integral thereof, and a derivative.

The operations of the movable device 13, the displacement amount detection unit 222, the temperature detection unit 223, the amplitude detection unit 224, the frequency detection unit 225, and the calculation unit 226 in this embodiment are the same as those in the first embodiment.

From the above, the third embodiment has a mirror portion 101 having a reflecting surface 14 and one or two fixing portions 105 supporting the mirror portion 101. A piezoelectric actuator 103 is provided, one end of which is connected to the mirror portion 101 and the other end of which is connected to the fixed portion 105, and the mirror portion 101 is swung about a predetermined axis with respect to the fixed portion 105 by piezoelectric driving. It has a drive circuit 221 that inputs a drive signal to the piezoelectric actuator 103, a drive amplitude control unit 229 that sets the drive amplitude of the drive circuit 221 and a piezoelectric sensor 104 that is a detection unit that detects the displacement amount of the piezoelectric actuator 103. .. It has a temperature detection unit 223 for measuring the ambient temperature of the piezoelectric actuator 103, an amplitude detection unit 224 for detecting the drive amplitude of the piezoelectric actuator drive signal, and a frequency detection unit 225 for detecting the drive frequency of the piezoelectric actuator drive signal. It has a calculation unit 226 that calculates the deflection angle of the mirror unit 101 based on the displacement amount information, the temperature information, the amplitude information of the piezoelectric drive signal, and the frequency information. With such a configuration, the output signal of the piezoelectric sensor 104 can be corrected based on the correction coefficient calculated from the drive amplitude, the drive frequency, and the ambient temperature. Therefore, even if there is an influence of the drive frequency, the runout angle of the mirror part 101 of the optical deflector is accurately calculated from the output of the piezoelectric sensor 104, and the runout angle of the mirror part 101 is based on the calculated runout angle. It can be controlled so that the desired runout angle is obtained.

[Fourth Embodiment]
Next, the optical deflector 204 in the fourth embodiment will be described with reference to FIG. 24. The optical deflector 204 in this embodiment includes a movable device 13, a drive circuit 221 and a displacement amount detection unit 222, a temperature detection unit 223, a calculation unit 226, an amplitude information acquisition unit 227, a frequency information acquisition unit 228, and a drive amplitude control unit 229. have.

The drive amplitude control unit 229 compares the runout angle set value of the mirror unit 101 input from the outside with the maximum runout angle value obtained from the runout angle information of the mirror unit 101 calculated by the calculation unit 226. Then, the amplitude of the drive circuit 221 is changed so that the runout angle of the mirror unit 101 becomes equal to the mirror runout angle set value, and the runout angle of the mirror unit 101 is controlled. For control, a method such as PID control is generally known.

From the above, the fourth embodiment has a mirror portion 101 having a reflecting surface 14 and one or two fixing portions 105 supporting the mirror portion 101. A piezoelectric actuator 103 is provided, one end of which is connected to the mirror portion 101 and the other end of which is connected to the fixed portion 105, and the mirror portion 101 is swung about a predetermined axis with respect to the fixed portion 105 by piezoelectric driving. A drive circuit 221 that inputs a drive signal to the piezoelectric actuator 103, a drive amplitude control unit 229 that sets the drive amplitude of the drive circuit 221 and a displacement amount that is arranged around the piezoelectric actuator 103 and detects the displacement amount of the piezoelectric actuator 103. It has a detection unit 222 and. It has a temperature detection unit 223 for measuring the ambient temperature of the piezoelectric actuator 103, an amplitude information acquisition unit 227 for acquiring amplitude information from the drive circuit 221 and a frequency information acquisition unit 228 for acquiring frequency information from the drive circuit 221. It has a calculation unit 226 that calculates the deflection angle of the mirror unit 101 based on the displacement amount information, the temperature information, the amplitude information, and the frequency information. With such a configuration, the output signal of the piezoelectric sensor 104 can be corrected based on the correction coefficients calculated from the amplitude, frequency, and ambient temperature. As a result, even if there is an influence of the drive frequency, the runout angle of the mirror part 101 of the optical deflector is accurately calculated from the output of the piezoelectric sensor 104, and the runout angle of the mirror part 101 is based on the calculated runout angle. Can be controlled to have a desired runout angle. In this embodiment, since the amplitude and frequency information of the drive signal can be acquired from the setting information without being detected from the drive signal itself, the correction can be performed accurately with a simple circuit.

The contents other than the above are the same as those in the second embodiment.

[Fifth Embodiment]
Next, a fifth embodiment will be described. The present embodiment is a movable device applicable to the light deflector according to the first to fourth embodiments. Specifically, as shown in FIG. 25, the movable device 300 in the present embodiment is a double-sided type (both end support beam) movable device that can rotate around the first axis and the second axis.

As shown in FIG. 25, the movable device 300 has a movable portion 110, first driving beams 120a and 120b, a fixing portion 140, and an electrode terminal 150. Further, the movable portion 110 includes a reflecting portion 112 including a reflecting surface 14, a supporting portion 113, torsion bars 115a and 115b, and second driving beams 116a and 116b.

The reflective portion 112 is formed of a silicon layer or the like. However, the present invention is not limited to this, and may be composed of an oxidizing material, an inorganic material, an organic material, or the like. The reflecting surface 14 is formed on the surface of the reflecting portion 112 in the positive Z direction. The reflective surface 14 is formed in a circular shape as shown by using a metal thin film containing aluminum, gold, silver, or the like or a multilayer film thereof.

A rib (not shown) for reinforcing the reflecting portion 112 is provided on the negative Z-direction surface of the reflecting portion 112. The ribs are formed of a silicon support layer, a silicon oxide layer, or the like, and by providing the ribs, deformation and distortion of the reflective portion 112 and the reflective surface 14 that occur during movement are suppressed.

The torsion bars 115a and 115b extend in the Y direction and are formed so as to sandwich the reflecting portion 112 in the Y direction. One end of the torsion bar 115a is connected to the reflecting portion 112, and one end of the torsion bar 115b is connected to the reflecting portion 112. The reflecting portion 112 is supported by torsion bars 115a and 115b.

The other end of the torsion bar 115a is connected to the second drive beam 116a, and the other end of the torsion bar 115b is connected to the second drive beam 116b. The second driving beams 116a and 116b, which are elastic beams, are provided with a piezoelectric portion on a surface in the positive Z direction. When a drive voltage is applied to the second drive beam 116a through an electrical wiring (not shown) laid out from the electrode terminal 150, the second drive beam 116a bends and deforms to cause the torsion bar 115a to twist.

Similarly, when a drive voltage is applied to the second drive beam 116b through an electrical wiring (not shown) laid out from the electrode terminal 150, the second drive beam 116b bends and deforms to cause the torsion bar 115b to twist.

The twisting of the torsion bars 115a and 115b serves as a rotational force, and the reflecting portion 112 rotates around the second axis.

On the other hand, the support portion 113 is formed so as to surround the reflection portion 112, the torsion bars 115a and 115b, and the second drive beams 116a and 116b from all sides. The support portion 113 is connected to the second drive beams 116a and 116b, and supports and restrains the second drive beams 116a and 116b. Further, the support portion 113 indirectly supports the reflection portion 112 and the torsion bars 115a and 115b via the second drive beams 116a and 116b.

A connecting portion 114a is formed at the lower left corner of the support portion 113 in the drawing, and the supporting portion 113 is connected to the first drive beam 120a via the connecting portion 114a. The connecting portion 114a extends in the positive X direction from the connection portion with the first driving beam 120a and connects the first driving beam 120a and the supporting portion 113.

A connecting portion 114b is formed at the upper right corner of the support portion 113 in the drawing, and the supporting portion 113 is connected to the first drive beam 120b via the connecting portion 114b. The connecting portion 114b extends in the negative X direction from the connection portion with the first driving beam 120b and connects the first driving beam 120b and the supporting portion 113.

The first drive beam 120a and the first drive beam 120b are supported by sandwiching the support portion 113 from both sides in the X direction.

The first drive beam 120a has a plurality of folded portions and connecting portions, and includes a meander structure in which a plurality of elastic beams are connected. Piezoelectric portions are provided on the positive Z-direction surfaces of the elastic beam formed by the folded portions. The end of the first drive beam 120a on the side not connected to the connecting portion 114a is connected to the fixing portion 140, and the fixing portion 140 fixes (supports and restrains) the first driving beam 120a.

Similarly, the first drive beam 120b has a plurality of folded portions and connecting portions, and includes a meander structure in which a plurality of elastic beams are connected. Piezoelectric portions are provided on the positive Z-side surfaces of the elastic beam formed by the folded portions. The end of the first drive beam 120b on the side not connected to the connecting portion 114b is connected to the fixing portion 140, and the fixing portion 140 fixes (supports and restrains) the first driving beam 120b. The first drive beams 120a and 120b are examples of "a pair of drive beams".

As shown in FIG. 25, the fixed portion 140 has a rectangular frame structure having four frame sides, and the movable portion 110 and the first driving beams 120a and 120b are surrounded by the four frame sides from all sides. I'm out.

On the other hand, a drive voltage is applied to the piezoelectric portions provided on the first drive beams 120a and 120b through electrical wiring (not shown) laid out from the electrode terminals 150.

Here, among the plurality of elastic beams included in the first driving beam 120a, the piezoelectric portion provided on the even-numbered elastic beam counting from the one closest to the reflecting portion 112 is referred to as the piezoelectric driving portion group 130A. Further, among the plurality of elastic beams included in the first driving beam 120b, the piezoelectric portion provided on the odd-numbered elastic beam counting from the one closest to the reflecting portion 112 is similarly referred to as the piezoelectric driving portion group 130A. The piezoelectric drive unit group 130A bends and deforms in the same direction when a drive voltage is applied to each piezoelectric unit at the same time. Using this deformation as rotational power, the movable portion 110 rotates around the first axis.

Further, among the elastic beams included in the first driving beam 120a, the piezoelectric portion provided on the odd-numbered elastic beam counting from the one closest to the reflecting portion 112 is referred to as the piezoelectric driving portion group 130B. Further, among the elastic beams included in the first driving beam 120b, the even-numbered elastic beam counting from the one closest to the reflecting portion 112 is similarly referred to as the piezoelectric driving portion group 130B. The piezoelectric drive unit group 130B bends and deforms in the same direction when a drive voltage is applied to each piezoelectric unit at the same time. Using this deformation as rotational power, the movable portion 110 rotates around the first axis in the direction opposite to the rotation by the piezoelectric drive unit group 130A.

In the first drive beams 120a and 120b, a plurality of piezoelectric portions of the piezoelectric drive unit groups 130A and 130B are flexed and deformed at the same time to accumulate the amount of rotation due to the bending deformation, and the runout angle of the movable portion 110 around the first axis. Can be increased. When the amount of rotation of the movable part 110 by the piezoelectric drive group 130A when a voltage is applied and the amount of rotation of the movable part 110 by the piezoelectric drive group 130B when a voltage is applied are balanced, the runout angle is It becomes zero.

Here, a semiconductor such as an SOI (Silicon On Insulator) substrate can be used as the substrate (wafer) forming the movable device 13. By processing with the semiconductor manufacturing technology, each component of the movable device 13 can be integrally formed. The first drive beams 120a and 120b and the second drive beams 116a and 116b may be formed after the SOI substrate is formed, or may be formed during the molding of the SOI substrate.

<How to drive a movable device>
Next, an example of the driving method of the movable device 13 will be described with reference to FIG. Due to the rotation around the second axis, the driving voltage is applied to the second driving beams 116a and 116b at the resonance frequency of the integrated structure consisting of the reflecting portion 112, the torsion bars 115a and 115b, and the second driving beams 116a and 116b. It is applied. The resonance frequency is 20 kHz or the like.

The piezoelectric portion of the second drive beam 116a to which one end of the torsion bar 115a is connected is deformed when a drive voltage is applied through the upper electrode and the lower electrode. Due to the deformation of the piezoelectric portion, the second drive beam 116a is bent and deformed, and the torsion bar 115a is twisted.

Similarly, the piezoelectric portion of the second drive beam 116b to which one end of the torsion bar 115b is connected is deformed when a drive voltage is applied through the upper electrode and the lower electrode. Due to the deformation of the piezoelectric portion, the second drive beam 116b is bent and deformed, and the torsion bar 115b is twisted.

The twisting of the torsion bars 115a and 115b serves as a rotational force, and the reflecting portion 112 reciprocates around the second axis. The waveform of the drive voltage applied to the second drive beams 116a and 116b is a sine wave or the like. The reflection unit 112 resonates and reciprocates in the cycle of the drive voltage waveform of the sine wave.

In the rotation around the first axis, the waveform of the drive voltage applied to the piezoelectric drive unit group 130A includes, for example, a sawtooth waveform. The frequency of the drive voltage is 60 Hz or the like. For the waveform of the drive voltage, let Tr be the time width of the rising period when the voltage value increases from the minimum value to the next maximum value, and Tf be the time width of the falling period when the voltage value decreases from the maximum value to the next minimum value. For example, the ratio of Tr: Tf = 9: 1 is preset. At this time, the ratio of Tr to one cycle is called the symmetry of the drive voltage.

The waveform of the drive voltage applied to the piezoelectric drive unit group 130B also includes a waveform such as a sawtooth wave. The frequency of the drive voltage is 60 Hz or the like. For the waveform of the drive voltage, for example, the ratio of Tf: Tr = 9: 1 is preset.

Further, the period of the waveform of the drive voltage applied to the piezoelectric drive unit group 130A and the period of the waveform of the drive voltage applied to the piezoelectric drive unit group 130B are set to be the same.

The sawtooth waveform of the drive voltage described above is generated by superimposing sinusoidal waves. Here, in the present embodiment, an example in which a sawtooth waveform is used as the waveform of the drive voltage is shown, but the present invention is not limited to this. The waveform may be changed according to the device characteristics of the movable device, such as the drive voltage of a waveform in which the apex of the sawtooth waveform is rounded, or the drive voltage of a waveform in which the linear region of the sawtooth waveform is curved.

The operation of the first drive beams 120a and 120b when the drive voltage is applied is as described above, and the movable portion 110 reciprocates around the first axis due to the bending deformation of the piezoelectric drive unit groups 130A and 130B.

<Cross-sectional shape of movable device>
Next, the cross-sectional shape of the movable device 13 will be described with reference to FIG. FIG. 26 is a cross-sectional view taken along the first axis in FIG. 25.

FIG. 26 shows the cross-sectional structure of the first driving beams 120a and 120b, the movable portion 110, and the fixed portion 140.

The first drive beams 120a and 120b have a silicon layer 303 and piezoelectric drive unit groups 130A and 130B formed on the positive Z-direction side surface of the silicon layer 303.

The silicon layer 303 is an elastic body that deforms according to the deformation of the piezoelectric drive groups 130A and 130B, and is composed of the silicon layer of the SOI substrate.

The piezoelectric drive groups 130A and 130B include a lower electrode 311 formed in order on the positive Z-direction surface of the silicon layer 303, a piezoelectric material 312, and an upper electrode 313. The lower electrode 311 and the upper electrode 313 are made of a metal thin film such as gold (Au) or platinum (Pt), and the piezoelectric material 312 is made of a piezoelectric material such as PZT (lead zirconate titanate).

Each of the piezoelectric drive units included in the piezoelectric drive unit groups 130A and 130B includes the same layer structure as described above. The piezoelectric drive units 130A and 130B may _{be covered with an insulating layer such as SiO 2} (silicon oxide), and electrical wiring may be provided in the positive Z direction thereof.

Next, the movable portion 110 includes a support layer 351, an interlayer film 352 laminated on the positive Z-direction surface of the support layer 351 and a movable layer 353 laminated on the positive Z-direction surface of the interlayer film 352. have.

The support layer 351 is made of single crystal silicon of an SOI substrate, an inorganic material, an organic material, or the like, and the interlayer film 352 is made of silicon oxide or the like. The movable layer 353 is an elastic body that deforms according to the deformation of the second driving beams 116a and 116b, and is composed of a silicon layer of an SOI substrate or the like. Here, as shown in FIG. 26, the support layer 351 includes a reflection surface support layer 351a on the negative Z direction side of the reflection surface 14 and a support portion support layer 351b on the negative Z direction side of the support portion 113. And are included.

Next, the fixing portion 140 includes a fixed support layer 361, an interlayer film 362 laminated on the positive Z-direction surface of the fixed support layer 361, and a silicon layer laminated on the positive Z-direction surface of the interlayer film 362. It has 363 and.

The fixed support layer 361 is made of single crystal silicon of an SOI substrate, an inorganic material, an organic material, or the like, and the interlayer film 362 is made of silicon oxide or the like. Further, the silicon layer 363 is composed of the silicon layer of the SOI substrate.

The silicon layers 303 and 363 and the movable layer 353 are not limited to the silicon layer of the SOI substrate, and may be composed of an oxidizing agent, an inorganic material, an organic material, or the like. Further, the support layer 351 and the fixed support layer 361 may be made of an inorganic material, an organic material, or the like.

By the way, the second driving beams 116a and 116b (see FIG. 25) in the movable portion 110 have a beam-shaped member and an upper electrode, a piezoelectric member, and a lower electrode in the beam-shaped member, and at least the upper electrode, the piezoelectric member, and the lower portion. The electrodes are covered with an insulating layer. Further, when the drive beam is driven, the insulating layer expands and contracts together with the piezoelectric member.

Further, the central portion of the second drive beam 116a is connected to the torsion bar 115a, and both ends of the second drive beam 116a are connected to a movable frame (support portion 113), and at least one of the upper electrode and the lower electrode is connected. The corner of the tip of the second driving beam 116a on the one end side of the electrode has a chamfered shape (for example, an arc shape or a tapered shape).

Similarly, the central portion of the second drive beam 116b is connected to the torsion bar 115b, and both ends of the second drive beam 116b are connected to a movable frame (support portion 113), and at least the upper electrode and the lower electrode are connected. The corner of the tip of one electrode on the one end side of the second driving beam 116b has a chamfered shape (for example, an arc shape or a tapered shape).

In the present embodiment, an example is shown in which the second drive beams 116a and 116b have a double-sided beam structure in which both ends are connected to the support portion 113, but as shown in FIG. 27, the second drive beam 116a and 116b may be a cantilever structure. In the cantilever structure, one end of the second drive beam 116a is connected to the support portion 113, and the other end is connected to the torsion bar 115a. Further, one end of the second drive beam 116b is connected to the support portion 113, and the other end is connected to the torsion bar 115b.

In the case of a cantilever structure, at least one of the upper electrode and the lower electrode provided on the second drive beams 116a and 116b has an arc shape or a tapered shape at the corner of the tip on the side connected to the torsion bar. Is formed in. More preferably, both the upper electrode and the lower electrode are formed in the same arc shape or taper shape.

With the above configuration, even if the dielectric strength decreases due to the driving of the second driving beams 116a and 116b, creepage discharge can be suppressed, and the durability of the movable device 13 can be improved.

Although examples of embodiments of the present invention have been described above, the present invention is not limited to such specific embodiments, and various aspects are described within the scope of the gist of the present invention described in the claims. It can be transformed and changed.

10 Optical scanning system 11 Control device 12, 12b Light source device 13, 13A, 13B, 13C, 13D, 13E, 13F Movable device 14 Reflective surface 15 Scanned surface 25 Light source device driver 26 Movable device driver 30 Control unit 31 Drive signal output unit 50 Laser head lamp 51 Mirror 52 Transparent plate 60 Head mount display 60a Front 60b Temple 61 Light guide plate 62 Half mirror 63 Wearer 101 Mirror part 102 Spring part 103 Piezoelectric actuator 104 piezoelectric sensor 105 Fixed part 106 Cantilever part 107 Support parts 201, 202 , 203, 204 Optical deflector 221 Drive circuit 222 Displacement amount detection unit 223 Temperature detection unit 224 Vibration detection unit 225 Frequency detection unit 226 Calculation unit 400 Automobile (example of vehicle)
500 Head-up display device (an example of an image projection device, an example of a head-up display)
650 Laser Printer 700 Rider Device (Example of Object Recognition Device)
702 Object 801 Package member 802 Mounting member 803 Transparent member

Japanese Patent No. 5400366

Claims (13)

A reflecting part having a reflecting surface that reflects light,
A support portion connected to the reflective portion at one end,
A fixed portion connected to the other end of the support portion and
A piezoelectric member that deforms the support portion to swing the reflective portion,
A frequency detection unit that detects the frequency of the drive signal input to the piezoelectric member, and
A displacement amount detecting unit that detects the displacement amount of the piezoelectric member, and
Have,
At least, a calculation unit that calculates the swing angle of the reflection unit based on the frequency information of the frequency detected by the frequency detection unit and the displacement amount information of the displacement amount detected by the displacement amount detection unit. An optical deflector characterized by having. It has an amplitude detection unit that detects the amplitude of the drive signal input to the piezoelectric member.
The calculation unit has at least frequency information of the frequency detected by the frequency detection unit, displacement amount information of the displacement amount detected by the displacement amount detection unit, and amplitude information of the amplitude detected by the amplitude detection unit. The optical deflector according to claim 1, wherein the swing angle of the reflecting portion is calculated based on the above. It has a temperature detection unit that detects the ambient temperature of the piezoelectric member.
The optical deflector according to claim 1 or 2, wherein the calculation unit further adds temperature information of the ambient temperature detected by the temperature detection unit to calculate the swing angle of the reflection unit. .. It has a drive signal generation unit that generates a drive signal that drives the piezoelectric member.
The second aspect of claim 2, wherein the calculation unit calculates the swing angle of the reflection unit using the frequency and amplitude of the drive signal obtained from the drive signal generation unit as the amplitude information and the frequency information. Light deflector. It has a temperature detection unit that detects the ambient temperature of the piezoelectric member.
The calculation unit calculates a correction coefficient by calculation using the temperature information of the ambient temperature detected by the temperature detection unit, the amplitude information, and the polynomial including the frequency information, and multiplies the displacement amount by the calculation unit. The optical deflector according to claim 4, wherein the swing angle of the reflecting portion is calculated. It has a drive amplitude control unit that controls a drive signal input from the drive signal generation unit to the piezoelectric member based on the swing angle information.
The light deflector according to claim 4 or 5, wherein the drive amplitude control unit controls the swing angle of the reflection unit by the piezoelectric member to be constant. The optical deflector according to any one of claims 1 to 6,
A light source that emits light and
With
An image projection device characterized in that light emitted from the light source is deflected and projected. A plurality of the light sources are provided, and the light source is provided.
The plurality of light sources emit light having different wavelengths.
Further provided with a compositing unit for synthesizing the plurality of lights emitted from the plurality of light sources.
The image projection apparatus according to claim 7, wherein the light synthesized in the synthesis unit is deflected and projected. A head-up display comprising the optical deflector according to any one of claims 1 to 6. A laser headlamp including the light deflector according to any one of claims 1 to 6. A head-mounted display comprising the light deflector according to any one of claims 1 to 6. The optical deflector according to any one of claims 1 to 6,
A light source that emits light and
With
An object recognition device characterized in that an object is recognized by deflecting light emitted from the light source, irradiating the object with the light, and detecting the reflected light reflected by the object. A vehicle having at least one of the head-up display according to claim 9, the laser headlamp according to claim 10, and the object recognition device according to claim 12.

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