JP7318240B2 - optical deflection element, optical deflection system, optical scanning system - Google Patents

Description

The present invention relates to an optical deflection element, an optical deflection system, an optical scanning system, an image projection device, a head-up display, a laser headlamp, a head-mounted display, an object recognition device, and a moving object.

2. Description of the Related Art In recent years, with the development of micromachining technology applying semiconductor manufacturing technology, MEMS (Micro Electro Mechanical Systems) devices have been developed as light deflection elements manufactured by microfabrication of silicon or glass.

An example of the MEMS device is a head-mounted display having a configuration in which the movable portion and the shaft portion are formed or coated with an oxide of zirconium (Zr), aluminum (Al), or yttrium (Y) (for example, See Patent Document 1).

By the way, in order to further improve the performance of MEMS devices, it is often required that the movable portion be large and move quickly. However, if one tries to move the movable part by a large amount, there is concern that stress will be concentrated on the movable part corresponding to the displacement, and it is difficult to move the movable part by a large amount if an attempt is made to move the movable part quickly using resonance.

For example, in a MEMS mirror that uses a metal material for its beams, it is possible to expand the deflection angle due to the characteristics of the material. I had to. In order to pattern a metal with a thickness of several tens of micrometers, dry etching, which is often used in semiconductor processes, is difficult, and laser processing and wet etching, which is difficult to control dimensions, must be used.

In addition, many metals have a relatively low melting point and a large coefficient of thermal expansion compared to silicon. Therefore, a special process that minimizes the temperature load during the semiconductor process for forming the MEMS must be used. Thus, metal materials have problems in terms of processing. On the other hand, in the method of adding a layer of different material to the beam that supports the mirror, although it is possible to control the operating frequency, the deflection angle depends on the mechanical properties of silicon, which is the main material of the beam. Couldn't expand. As described above, there is a problem that it is difficult to achieve both an increase in deflection angle (movable range) and a high speed without impairing workability.

In the head-mounted display described above, a material with high breaking strength is used for the beam portion, but it is not possible to achieve both expansion of the movable area and speeding up.

SUMMARY OF THE INVENTION The present invention has been made in view of the above, and an object of the present invention is to make it possible to expand the movable region and increase the speed of an optical deflection element without impairing workability.

The present optical deflection element rotates a movable portion having a reflecting surface to deflect light incident on the reflecting surface , is connected to the movable portion, and is connected to the movable portion so as to move the movable portion along the first axis. a first driving portion that drives around; and a first supporting portion that supports the movable portion and the first driving portion, wherein the first driving portion is a beam that rotatably supports the movable portion. wherein the movable portion is composed of a first layer and a second layer, the first layer has the reflective surface, and all of the first layer excluding the reflective surface and the beam portion are carbonized It is composed only of silicon, alumina, sapphire, silicon nitride, zirconia, diamond, or compounds containing these as main materials.

According to the disclosed technology, it is possible to achieve both expansion of the movable region and high speed operation without impairing workability in the optical deflection element.

1 is a schematic diagram of an example optical scanning system; FIG. 1 is a hardware configuration diagram of an example of an optical scanning system; FIG. It is a functional block diagram of an example of a control device. 4 is a flowchart of an example of processing related to an optical scanning system; 1 is a schematic diagram of an example of a vehicle equipped with a head-up display device; FIG. 1 is a schematic diagram of an example of a head-up display device; FIG. 1 is a schematic diagram of an example of an image forming apparatus equipped with an optical writing device; FIG. 1 is a schematic diagram of an example of an optical writing device; FIG. 1 is a schematic diagram of an example vehicle equipped with a lidar device; FIG. 1 is a schematic diagram of an example lidar device; FIG. It is a schematic diagram explaining an example of composition of a laser headlamp. It is a schematic perspective view which shows an example of a structure of a head mounted display. It is a figure which shows an example of a part of structure of a head mounted display. 1 is a schematic diagram illustrating an example of a packaged mobile device; FIG. It is a top view which illustrates the movable device which concerns on 1st Embodiment. FIG. 16 is a cross-sectional view taken along line AA of FIG. 15; FIG. 16 is a cross-sectional view taken along line BB of FIG. 15; It is a figure (1) explaining the simulation of a movable apparatus. It is a figure (2) explaining the simulation of a movable apparatus. It is a figure (3) explaining the simulation of a movable apparatus. It is a figure (4) explaining the simulation of a movable apparatus. It is a figure (5) explaining the simulation of a movable apparatus. It is a figure (6) explaining the simulation of a movable apparatus. It is a top view which illustrates the movable device which concerns on 2nd Embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail.

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

A schematic diagram of an example of an optical scanning system is shown in FIG. As shown in FIG. 1, an optical scanning system 10 is a system that optically scans a surface 15 to be scanned by deflecting light emitted from a light source device 12 by a reflecting surface 14 of a movable device 13 under the control of a control device 11 . be.

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 emits laser light. Note that the scanned surface 15 is, for example, a screen.

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

The light source device 12 irradiates the light source based on the input drive signal. The movable device 13 moves the reflecting surface 14 in at least one of the directions of one axis and the directions of two axes based on the input drive signal.

As a result, for example, the reflecting surface 14 of the movable device 13 is reciprocally moved in two axial directions within a predetermined range under the control of the control device 11 based on image information, which is an example of optical scanning information, and the light is incident on the reflecting surface 14 . An arbitrary image can be projected onto the surface 15 to be scanned by deflecting the irradiation light from the light source device 12 around a certain axis and performing optical scanning. In addition, the detail of the movable apparatus of this embodiment and the detail of control by a control apparatus are mentioned later.

Next, a 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. 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, which are electrically connected to each other. Among 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 device that reads programs and data from a storage device such as a ROM 22 onto a RAM 21 and executes processing to achieve 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 nonvolatile storage device that can retain programs and data even when the power is turned off, and stores processing programs and data that the CPU 20 executes to control each function of the optical scanning system 10 . there is

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

The external I/F 24 is, for example, an interface with an external device, network, or the like. External devices include, for example, host devices such as PCs (Personal Computers), and storage devices such as USB memories, SD cards, CDs, DVDs, HDDs, and SSDs. 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 be configured to enable connection or communication with an external device, and the external I/F 24 may be prepared for each external device.

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

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

In the control device 11 , the CPU 20 acquires optical scanning information from an external device or network via the external I/F 24 . It should be noted that any configuration may be used as long as the CPU 20 can acquire the optical scanning information. 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 to optically scan the surface 15 to be scanned. For example, when an image is displayed 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 writing data indicating the writing order and 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 irradiation with light for object recognition.

The control device 11 can implement the functional configuration described below by means of commands from the CPU 20 and the hardware configuration shown in FIG.

Next, the functional configuration of the controller 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 the controller of the optical scanning system.

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

The control unit 30 is implemented by, for example, the CPU 20 and the FPGA 23 , acquires optical scanning information from an external device, converts the optical scanning information into control signals, and outputs the control signals 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 through predetermined processing, 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, etc., 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 driving of the light source device 12 or the movable device 13 . For example, in the light source device 12, it is a driving voltage for controlling the irradiation timing and irradiation intensity of the light source. Further, for example, in the movable device 13 , it is a drive voltage for controlling the timing and movable range for moving the reflecting surface 14 of the movable device 13 .

Next, a process of optically scanning the surface 15 to be scanned 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 S<b>12 , the control section 30 generates a control signal from the acquired optical scanning information and outputs the control signal to the drive signal output section 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 S14, the light source device 12 performs light irradiation based on the input drive signal. Also, 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 optically scanned.

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

In the optical scanning system 10, one control device 11 is provided with the functions of the control section 30 of the light source device 12 and the movable device 13 and the function of the drive signal output section 31, but these functions exist as separate entities. Alternatively, for example, a configuration in which a drive signal output device having a drive signal output section 31 is provided separately from the control device 11 having the control section 30 may be employed. In the optical scanning system 10, the movable device 13 having the reflecting surface 14 and the control device 11 may constitute an optical deflection system that deflects the light.

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

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

An image projection device is a device that projects an image by optical scanning, such as a head-up display device.

As shown in FIG. 5, the head-up display device 500 is installed near the windshield (windshield 401 etc.) of the automobile 400, for example. The projection light L emitted from the head-up display device 500 is reflected by the windshield 401 and travels toward the observer (driver 402) who is the user. Accordingly, 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 projected light reflected by the combiner.

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

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 can visually recognize the intermediate image as a virtual image.

Color laser beams emitted from laser light sources 501R, 501G, and 501B are collimated by collimator lenses 502, 503, and 504, respectively, and combined by two dichroic mirrors 505 and 506, respectively. 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 projection light L that has been two-dimensionally scanned by the movable device 13 is reflected by the free-form surface mirror 509 and corrected for distortion, and then converged 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 projection light L incident on the intermediate screen 510 in microlens units.

The movable device 13 reciprocates the reflecting surface 14 in two axial directions, and two-dimensionally scans the projection light L incident on the reflecting surface 14 . The drive control of this movable device 13 is performed in synchronization with the light emission timings of the laser light sources 501R, 501G, and 501B.

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

In addition, the image projection device is used not only for vehicles and mounting members, but also for mobile objects such as aircraft, ships, and mobile robots, or working robots that operate objects to be driven such as manipulators without moving from the spot. It may be mounted on a non-moving object.

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

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

FIG. 7 shows an example of an image forming apparatus in which the optical writing device 600 is incorporated. Also, FIG. 8 is a schematic diagram of an example of an optical writing device.

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

As shown in FIG. 8, in an optical writing device 600, a laser beam from a light source device 12 such as a laser element passes through an imaging optical system 601 such as a collimator lens, and then passes through a movable device 13 having a reflecting surface 14. Axially or biaxially deflected. The laser beam deflected by the movable device 13 then passes through a scanning optical system 602 consisting of a first lens 602a, a second lens 602b, and a reflecting mirror portion 602c, and passes through the surface to be scanned 15 (for example, a photosensitive drum or photosensitive paper). ) to perform optical writing. The scanning optical system 602 forms a spot-like light beam on the surface 15 to be scanned. Also, the movable device 13 having the light source device 12 and the reflecting surface 14 is driven based on the control of the control device 11 .

Thus, the optical writing device 600 can be used as a component of an image forming apparatus having a printer function using laser light. In addition, by making the scanning optical system different so that optical scanning can be performed not only in one axial direction but also in two axial directions, a laser label device or the like that prints by deflecting a laser beam onto a thermal medium, performing optical scanning, and heating the media. can be used as a component of the image forming apparatus.

The movable device 13 having the reflecting surface 14 applied to the optical writing device consumes less power for driving than a rotating polygonal mirror using a polygon mirror or the like, so it contributes to power saving of the optical writing device. Advantageous. In addition, since wind noise when the movable device 13 vibrates is smaller than that of the rotating polygon mirror, it is advantageous for improving the quietness of the optical writing device. The optical writing device requires an overwhelmingly smaller installation space than the rotary polygon mirror, and the amount of heat generated by the movable device 13 is also very small. be.

[Object recognition device]
Next, an 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.

FIG. 9 is a schematic diagram of a vehicle equipped with a LiDAR (Laser Imaging Detection and Ranging) device, which is an example of an object recognition device. Also, FIG. 10 is a schematic diagram of an example of a lidar device.

An object recognition device is a device that recognizes an object in a target direction, such as a lidar device.

As shown in FIG. 9, the lidar device 700 is mounted on, for example, an automobile 701, optically scans a target direction, and receives reflected light from a target object 702 existing in the target direction. to recognize

As shown in FIG. 10, the laser light emitted from the light source device 12 passes through an incident optical system composed of a collimator lens 703, which is an optical system that converts divergent light into substantially parallel light, and a plane mirror 704, and is reflected. A movable device 13 having a surface 14 is scanned in one or two axes. Then, the light is projected onto an object 702 in front of the device through a projection lens 705 or the like, which is a projection optical system. The light source device 12 and the movable device 13 are driven and controlled by the control device 11 . Reflected light reflected by the target object 702 is photodetected by a photodetector 709 . That is, the reflected light is received by an imaging device 707 via a condensing lens 706 or the like, which is an incident light detecting and receiving optical system, and the imaging device 707 outputs a detection signal to a 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 measurement circuit 710 .

The distance measuring circuit 710 detects the target object based on the time difference between the timing at which the light source device 12 emits laser light and the timing at which the photodetector 709 receives the laser light, or the phase difference for each pixel of the image sensor 707 that receives the light. The presence or absence of the object 702 is recognized, and distance information to the target object 702 is calculated.

Since the movable device 13 having the reflecting surface 14 is less likely to be damaged than a polygonal mirror and is small, it is possible to provide a compact radar device with high durability. Such a lidar device is attached to a vehicle, for example, and can recognize the presence or absence of an obstacle and the distance to the obstacle by optically scanning a predetermined range.

A lidar device is mounted not only on a vehicle but also on a mobile object such as an aircraft, a ship, a mobile robot, or a non-mobile object such as a working robot that operates a driven object such as a manipulator without moving from its place. may

In the above object recognition device, the lidar device 700 has been described as an example. Any device may be used as long as it recognizes the target object 702 by receiving reflected light, and is not limited to the above-described embodiments.

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

[Laser headlamp]
Next, a laser headlamp 50 in which the movable device of the present embodiment is applied to an automobile headlight will be described with reference to FIG. FIG. 11 is a schematic diagram illustrating an example of the configuration of the laser headlamp 50. As shown in FIG.

The laser headlamp 50 has a control device 11 , a light source device 12 b , 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 blue laser light. Light emitted from the light source device 12 b 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 a 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 enters the transparent plate 52 . The transparent plate 52 is coated with a yellow phosphor on its front or back surface. As the blue laser light from the mirror 51 passes through the yellow phosphor coating on the transparent plate 52, it changes to white within the legal headlight color range. 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 undergoes predetermined scattering when passing through the phosphor of the transparent plate 52 . This alleviates the glare in the illuminated object in front of the vehicle.

When applying the movable device 13 to a headlight of a car, 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 the three primary colors of light, namely blue, green, and red phosphors. Even in this case, the light passing through the transparent plate 52 can be converted into white light, and the front of the automobile can be illuminated with white light.

Note that the laser headlamp 50 can be used not only in vehicles, but also in mobile objects such as aircraft, ships, and mobile robots, or non-moving robots such as working robots that operate a driven object such as a manipulator without moving from the spot. It may be mounted on the body.

[Head-mounted display]
Next, a head mounted display 60 to which the movable device of the present embodiment is applied will be described with reference to FIGS. 12 and 13. FIG. Here, the head-mounted display 60 is a head-mounted display that can be worn on a person's head, and can have a shape similar to eyeglasses, for example. The head-mounted display will hereinafter be abbreviated as HMD.

FIG. 12 is a perspective view illustrating the appearance of the HMD 60. FIG. In FIG. 12, the HMD 60 is composed of a front 60a and a temple 60b, which are provided approximately symmetrically in pairs on the left and right sides. The front 60a can be composed of, for example, a light guide plate 61, and the optical system, control device, and the like can be incorporated in the temple 60b.

FIG. 13 is a diagram partially illustrating the configuration of the HMD 60. As shown in FIG. Although FIG. 13 illustrates the configuration for the left eye, the HMD 60 has the same configuration for the right eye.

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

The light source unit 530 unitizes the laser light sources 501R, 501G and 501B, the collimator lenses 502, 503 and 504, and the dichroic mirrors 505 and 506 with an optical housing as described above. In the light source unit 530, the three-color laser beams from the laser light sources 501R, 501G, and 501B are synthesized by the dichroic mirrors 505 and 506. 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 section 507 . The movable device 13 moves the reflecting surface 14 in the XY directions based on a signal from the control device 11 and two-dimensionally scans the light from the light source unit 530 . The driving 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 scanning light.

Scanning light from the movable device 13 enters the light guide plate 61 . The light guide plate 61 guides the scanning light to the half mirror 62 while reflecting it on the inner wall surface. The light guide plate 61 is made of 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 side 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. An image of the scanning light is reflected by the half mirror 62 and formed on the retina of the wearer 63 . Alternatively, an image is formed on the retina of the wearer 63 by the reflection on the half mirror 62 and the lens effect of the crystalline lens in the eyeball. Further, the spatial distortion of the image is corrected by the reflection on the half mirror 62 . The wearer 63 can observe an image formed by light scanned in the XY directions.

Since 62 is a half mirror, the wearer 63 observes an image of light from the outside and an image of scanning light superimposed. By providing a mirror in place of the half mirror 62, the light from the outside may be eliminated and only the image by the scanning light may be observed.

[Packaging]
Next, the packaging of the movable device of this embodiment will be described with reference to FIG. 14 .

FIG. 14 is a schematic diagram of an example of a packaged mobile device.

As shown in FIG. 14 , the movable device 13 is attached to an attachment member 802 arranged inside a package member 801, and a part of the package member 801 is covered with a transparent member 803 to be hermetically sealed. be done. Furthermore, the inside of the package is sealed with an inert gas such as nitrogen. As a result, deterioration due to oxidation of the movable device 13 is suppressed, and durability against environmental changes such as temperature is improved.

Details of the movable device of the present embodiment used in the optical deflection system, the optical scanning system, the image projection device, the optical writing device, the object recognition device, the laser headlamp, and the head mounted display described above are shown in the drawings below. will be described with reference to. In addition, in each drawing, the same code|symbol may be attached|subjected to the same component part, and the overlapping description may be abbreviate|omitted.

In the description of the embodiments, sub-scanning is optical scanning with the first axis as the center of rotation, and main scanning is optical scanning with the second axis as the center of rotation. Also, the terms "rotation", "swing" and "movability" in the terms of the embodiment are synonymous. Furthermore, among the directions indicated by the arrows, the X direction is the direction parallel to the first axis, the Y direction is the direction parallel to the second axis, and the Z direction is the direction perpendicular to the XY plane. Note that the Z direction is an example of the “stacking direction”.

[First embodiment]
<Structure of movable device>
15 is a plan view illustrating the movable device according to the first embodiment; FIG. 16 is a cross-sectional view taken along line AA of FIG. 15. FIG. 17 is a cross-sectional view taken along line BB of FIG. 15. FIG.

The movable device 13 shown in FIG. 15 is a cantilever that rotates a movable portion having a reflecting surface by resonance vibration and deflects light incident on the reflecting surface in two axial directions (around the first axis and the second axis). type optical deflector.

The movable device 13 has a structure that enables rotation of the mirror section 101 about a first axis corresponding to the main scanning direction and rotation of the mirror section 101 about a second axis corresponding to the sub-scanning direction. I have. That is, the movable device 13 can deflect incident light while scanning in two axial directions by rotating the mirror section 101 in two axial directions. The structure of the movable device 13 will be described in detail below.

The movable device 13 includes a mirror portion 101 that reflects incident light, and first driving portions 110a and 110b that are connected to the mirror portion 101, which is a movable portion, and drive the mirror portion 101 around a first axis parallel to the Y axis. , a first supporting portion 120 that supports the mirror portion 101 and the first driving portions 110a and 110b, and a mirror portion 101 and the first supporting portion 120 connected to the first supporting portion 120 parallel to the X axis (first axis a second drive portion 130a and 130b driving about a second axis (perpendicular to and perpendicular to the axis); a second support portion 140 supporting the second drive portion 130a and 130b; and an electrode connection portion 150 electrically connected to the portions 130a and 130b.

The movable device 13 is formed by, for example, forming a SOS (Sapphire On Silicon) substrate having a sapphire/silicon structure by etching or the like. By forming the portions 131a to 131f and 132a to 132f, the electrode connection portion 150, and the like, each constituent portion is integrally formed. The formation of each component described above may be performed after the SOS substrate is molded, or may be performed during the molding of the SOS substrate.

The SOS substrate is a substrate in which a silicon oxide layer is provided on a first silicon layer made of single crystal silicon (Si), and an active layer made of sapphire is further provided on the silicon oxide layer. Hereinafter, the first silicon layer will be referred to as a support layer 161 and the sapphire active layer will be referred to as an active layer 163 . Note that the silicon oxide layer 162 may be omitted.

The active layer 163 is made of, for example, silicon carbide (SiC), aluminum oxide ( _{Al2O3 , alumina} , sapphire), silicon nitride ( _Si3N4 ), diamond, aluminum nitride (AlN), zirconium oxide ( _ZrO2 ), or the like. It is not limited to sapphire, as long as it is a material that has greater fracture toughness, elastic limit, and Young's modulus than silicon. In addition, since the active layer 163 has a smaller thickness in the Z-axis direction than in the X-axis direction or the Y-axis direction, the member composed only of the active layer 163 functions as an elastic portion having elasticity.

Note that the SOS substrate does not necessarily have to be planar, and may have a curvature or the like. In addition, if the material of the active layer 163 is a material that can be integrally molded by etching treatment or the like, can be partially elastic, and has higher fracture toughness, elastic limit, and Young's modulus than silicon, as described above. For example, the member used to form the movable device 13 is not limited to the SOS substrate.

The mirror section 101 is a movable section, and includes, for example, a circular mirror section base 102 and a reflecting surface 14 formed on the +Z side surface of the mirror section base 102 . The mirror section substrate 102 is composed of an active layer 163 . The reflecting surface 14 is composed of a metal thin film containing, for example, aluminum, gold, silver, or the like.

Further, the mirror portion 101 may have ribs for reinforcing the mirror portion formed on the −Z side surface of the mirror portion base 102 . The ribs are composed of the support layer 161 and the silicon oxide layer 162, or only the support layer 161, and can suppress distortion of the reflecting surface 14 caused by movement.

The first drive portions 110a and 110b have two torsion bars 111a and 111b each having one end connected to the mirror portion base 102 and extending in the first axis direction to movably support the mirror portion 101, and one end connecting the torsion bar 111a. or 111b and the other end of which is connected to the inner periphery of the first support 120.

As shown in FIG. 16, the torsion bars 111a and 111b are composed of an active layer 163. As shown in FIG. The first piezoelectric drive portions 112a and 112b are formed in the order of the lower electrode 201, the piezoelectric portion 202, and the upper electrode 203 on the +Z side surface of the active layer 163, which is the elastic portion. The upper electrode 203 and the lower electrode 201 are made of, for example, gold (Au) or platinum (Pt). The piezoelectric portion 202 is made of, for example, PZT (lead zirconate titanate), which is a piezoelectric material.

Returning to FIG. 15, the first support section 120 is composed of, for example, three layers of a support layer 161, a silicon oxide layer 162, and an active layer 163, or two layers of a support layer 161 and an active layer 163. It is a rectangular support formed to surround.

The second driving portions 130a and 130b are composed of, for example, a plurality of second piezoelectric driving portions 131a to 131f and 132a to 132f connected in a folded manner. One ends of the second drive portions 130 a and 130 b are connected to the outer peripheral portion of the first support portion 120 , and the other ends are connected to the inner peripheral portion of the second support portion 140 .

At this time, the connection point between the second drive portion 130a and the first support portion 120, the connection point between the second drive portion 130b and the first support portion 120, the connection point between the second drive portion 130a and the second support portion 140, and the The connection point between the second driving portion 130b and the second supporting portion 140 is symmetrical with respect to the center of the reflecting surface 14. As shown in FIG.

Here, the second piezoelectric drivers 131b, 131d, and 131f, and 132a, 132c, and 132e constitute a piezoelectric driver group 170A. The piezoelectric driving section group 170A bends and deforms in the same direction when drive voltages are simultaneously applied to the piezoelectric sections. Using this deformation as a turning force, the mirror section 101 turns around the first axis.

Further, the second piezoelectric drive units 131a, 131c, 131e, and 132b, 132d, and 132f constitute a piezoelectric drive unit group 170B. The piezoelectric driving section group 170B bends and deforms in the same direction when drive voltages are simultaneously applied to the piezoelectric sections. Using this deformation as a turning force, the movable part 110 turns around the first axis in a direction opposite to the turning by the piezoelectric driving part group 170A.

As shown in FIG. 17, the second drive portions 130a and 130b are formed in the order of the lower electrode 201, the piezoelectric portion 202, and the upper electrode 203 on the +Z side surface of the active layer 163, which is the elastic portion. The upper electrode 203 and the lower electrode 201 are made of, for example, gold (Au) or platinum (Pt). The piezoelectric portion 202 is made of, for example, PZT (lead zirconate titanate), which is a piezoelectric material.

Returning to FIG. 15, the second support section 140 is composed of, for example, three layers of a support layer 161, a silicon oxide layer 162, and an active layer 163, or two layers of a support layer 161 and an active layer 163. It is a rectangular support formed to surround the first drive portions 110a and 110b, the first support portion 120, and the second drive portions 130a and 130b.

The electrode connection portion 150 is formed, for example, on the +Z side surface of the second support portion 140, and connects the upper electrodes 203 and the lower electrodes 201 of the first piezoelectric drive portions 112a and 112b and the second piezoelectric drive portions 131a to 131f. is electrically connected to the control device 11 via electrode wiring made of aluminum (Al) or the like. The upper electrode 203 or the lower electrode 201 may be directly connected to the electrode connection portion 150, or may be indirectly connected by connecting the electrodes to each other.

In the present embodiment, the case where the piezoelectric portion 202 is formed only on one surface (the surface on the +Z side) of the active layer 163, which is the elastic portion, has been described as an example. However, the piezoelectric portion 202 may be provided on the other surface of the elastic portion (for example, the surface on the -Z side), or the piezoelectric portion 202 may be provided on both one surface and the other surface of the elastic portion.

Further, the shape of each component is not limited to the shape of the embodiment as long as the mirror portion 101 can be driven around the first axis or around the second axis. For example, the torsion bars 111a and 111b and the first piezoelectric drive portions 112a and 112b may have curved shapes.

Furthermore, on the +Z side surfaces of the upper electrodes 203 of the first driving portions 110a and 110b, on the +Z side surfaces of the first support portions 120, on the +Z side surfaces of the upper electrodes 203 of the second driving portions 130a and 130b, An insulating layer made of a silicon oxide layer may be formed on at least one of the +Z side surfaces of the second support portion 140 .

At this time, the electrode wiring is provided on the insulating layer, and only the connection spots where the upper electrode 203 or the lower electrode 201 and the electrode wiring are connected are partially removed or not formed as openings. As a result, the degree of freedom in designing the first drive units 110a and 110b, the second drive units 130a and 130b, and the electrode wiring can be increased, and short circuits due to contact between electrodes can be suppressed. The silicon oxide layer also functions as an antireflection material.

<simulation>
Analysis results of the movable area in the X-axis direction of the mirror unit 101, that is, the mirror deflection angle and the operation speed, are shown. In addition, in this embodiment, since driving is performed by resonance, the operating speed corresponds to the resonance frequency.

In order to facilitate the explanation, the model 1 of the movable device as shown in FIGS. 18 to 20 was used for the analysis. A model 1 has an active layer 2, a support layer 3, and a piezoelectric section 6 for driving. The active layer 2 includes a movable mirror portion 4 , two beams (torsion bars) 5 that movably support the movable mirror portion 4 , and a diaphragm portion 7 . The active layer 2 is a representative example of the first layer according to the invention, and the support layer 3 is a representative example of the second layer according to the invention.

Since the movable mirror portion 4, the beam portion 5, and the diaphragm portion 7 are integrated as the active layer 2, the movable mirror portion 4, the beam portion 5, or the diaphragm portion that occurs when only the material of the beam portion 5 is changed. The problem of adhesion between the portion 7 and the movable mirror portion 4 does not arise. The support layer 3 consists of ribs 8 that reinforce the movable mirror portion 4 .

Regarding the material of the active layer 2, since the movable mirror section 4 is driven by resonance, high-speed driving is possible if the resonance frequency is high. Generally, the resonance frequency f of the beam is represented by Equation (1).

式（１）において、Ｌは梁の長さ［ｍ］、Ｅはヤング率［Ｎ／ｍ^２］、ρは密度［ｋｇ/ｍ^３］、Ａは断面積［ｍ^２］、Ｉは断面二次モーメント［ｍ^４］、ｋｎは境界条件やモード等によって決まる定数である。

In formula (1), L is the length of the beam [m], E is the Young's modulus [N/m ² ], ρ is the density [kg/m ³ ], A is the cross-sectional area [m ² ], and I is the cross-sectional area The second moment [m ⁴ ], kn is a constant determined by boundary conditions, modes, and the like.

The geometric moment of inertia I is expressed by Equation (2), for example, when the cross section is a rectangle with a width of b and a thickness of h.

式（１）から、高速駆動、つまり共振周波数を大きくするためにはヤング率は大きく、密度は小さい材料が望ましい。一方、振れ角はできるだけ大きくしたいため、大きな力まで耐えられるよう破壊靭性、弾性限界、曲げ強度は大きい材料が好ましく、ヤング率は小さい材料が好ましい。

From equation (1), a material with a large Young's modulus and a small density is desirable for high-speed driving, that is, for increasing the resonance frequency. On the other hand, since it is desirable to increase the deflection angle as much as possible, a material with high fracture toughness, elastic limit, and bending strength is preferable so that it can withstand a large force, and a material with a low Young's modulus is preferable.

From the viewpoint of Young's modulus, there is a trade-off relationship between the resonance frequency and the deflection angle, but considering workability, the thickness of the active layer 2 should be as thin as possible. If the thickness of the active layer 2 is thin, the resonance frequency will be lower than the equations (1) and (2), so a material with a high Young's modulus is selected.

In summary, the preferred material for the active layer 2 is a material that has greater fracture toughness, elastic limit, and Young's modulus than silicon, which is currently a common material, and preferably has a low density and is compatible with semiconductor processes. be. Silicon carbide (SiC), silicon nitride (Si ₃ N ₄ ), diamond, aluminum nitride (AlN), zirconium oxide (ZrO ₂ ), and the like are desirable as such materials, for example.

Many of these materials are difficult to etch, and it is difficult to etch a thick film. However, since the Young's modulus is high, a high resonance frequency can be realized even with a thin film from equations (1) and (2). Therefore, workability issues are also minimized.

As the material of the support layer 3, silicon, silicon with an oxide film, or the like is desirable in consideration of process aspects such as workability and heat conduction.

Specific simulation results of workability, operating frequency, and deflection angle will be described with reference to FIGS. 21 to 23 and Tables 1 to 4.

In model 1, the diameter of the movable mirror portion 4 is 1 mm, the length of the beam portion 5 is 500 μm, the width is 50 μm or 100 μm, the thickness of the piezoelectric portion 6 is 2 μm, and the thickness of the rib 8 is 200 μm.

The material of the active layer 2 is silicon (reference) or silicon carbide (SiC) or alumina (Al ₂ O ₃ , polycrystalline or amorphous of aluminum oxide) or sapphire (Al ₂ O ₃ , single crystal of aluminum oxide). , silicon nitride (Si ₃ N ₄ ) or zirconia (ZrO ₂ , zirconium oxide), and diamond, the material of the support layer 3 is silicon, and the piezoelectric body 6 is PZT (lead zirconate titanate). Simulations are performed using ANSYS (analysis software).

Table 1 summarizes the physical properties of each active layer material. Regarding Young's modulus and Poisson's ratio, materials other than silicon were treated as isotropic materials. Materials other than silicon have higher fracture toughness, elastic limit and Young's modulus than silicon.

Workability will be explained. A dry-etchable material with easy dimensional accuracy is preferred. Silicon carbide and silicon nitride are dry-etched with fluorine-based gas, alumina, sapphire, and zirconia with chlorine-based gas, and diamond with oxygen gas. Silicon carbide and sapphire have a track record of deep etching of several tens of μm by dry etching.

21 and 22 show the dependence of the resonance frequency on the active layer thickness for each material when the beam width is 50 μm or 100 μm. For each active layer material, the film thickness that can realize a resonance frequency of 32 kHz, for example, is obtained as shown in Table 2. When the beam width is 50 μm, silicon: 108 μm, silicon carbide: 56 μm, alumina: 67 μm, sapphire: 58 μm, silicon nitride: 77 μm, diamond: 34 μm, and when the beam width is 100 μm, silicon: 52 μm, silicon carbide: 34 μm, alumina: 37 μm, sapphire: 35 μm, silicon nitride: 41 μm, zirconia: 58 μm, diamond: 24 μm, and zirconia. It can be seen that other materials can achieve 32 kHz resonance with a film thickness thinner than that of silicon. Zirconia should be thicker than Si due to its higher density.

Operation speed will be explained. Table 3 shows the resonance frequency of each material when the beam width is 50 μm and the thickness of the active layer 2 is 40 μm, or when the beam width is 100 μm and the thickness of the active layer 2 is 40 μm. When the beam width is 50 μm and the thickness of the active layer 2 is 40 μm, silicon: 15.4 kHz, silicon carbide: 24.7 kHz, alumina: 22.1 kHz, sapphire: 24.2 kHz, silicon nitride: 20.2 kHz, zirconia: When 14.2 kHz, diamond 37.8 kHz, beam width 100 μm, active layer 2 thickness 40 μm, silicon: 24.0 kHz, silicon carbide: 39.4 kHz, alumina: 35.2 kHz, sapphire: 38.2 kHz, Silicon nitride: 31.9 kHz, zirconia: 22.4 kHz, diamond 43.1 kHz, materials other than zirconia can be driven at a higher speed than silicon.

A swing angle will be explained. In Model 1, a state in which the ends of the diaphragm portion 7 in the ±Y direction and the center of the movable mirror portion 4 are constrained is assumed, and a concentrated load is applied to one end of the movable mirror portion 4 in the −Z direction. A deflection angle θ is calculated from the amount of displacement of the movable mirror section 4 in the ±Z directions using Equation (3).

式（３）において、Ｚはミラー端のＺ方向の変位量、Ｌはミラー直径である（図２３）。

In equation (3), Z is the amount of displacement of the mirror edge in the Z direction, and L is the diameter of the mirror (FIG. 23).

The maximum deflection angle is defined as the deflection angle when the maximum value of the first principal stress applied to the beam portion 5 coincides with the maximum stress of the material of the active layer 2 by changing the applied concentrated load. The maximum stress is a hypothetical fracture stress obtained by multiplying the documented values of fracture toughness and elastic limit by a coefficient, based on a model in which both the active layer 2 and the support layer 3 are made of Si.

Table 4 shows the maximum deflection angle for each active layer material in a structure capable of high-speed driving, for example, a 32 kHz resonant structure as shown in Table 3, obtained by the above method. When the beam width is 50 μm, silicon: 9.3°, silicon carbide: 19.8°, alumina: 17.5°, sapphire: 22.0°, silicon nitride: 22.1°, diamond: 55.6° When the beam width is 100 μm, silicon: 7.8°, silicon carbide: 15.5°, alumina: 19.7°, sapphire: 17.1°, silicon nitride: 16.5°, zirconia: 24.4°. °, diamond: 82.7°, any material can achieve a deflection angle about twice or more than silicon in a 32 kHz resonant structure.

As described above, the entire active layer 2 except for the reflecting surface is made of silicon carbide, alumina, sapphire, silicon nitride, zirconia, or diamond, which has higher fracture toughness, higher elastic limit, and higher Young's modulus than silicon. It is preferably composed of Also, the support layer 3 is preferably made of silicon.

In this case, silicon carbide, alumina, sapphire, silicon nitride, and diamond are thinner than silicon, can be driven at high speed, and have a larger deflection angle than silicon. Angular realizations are possible. As for zirconia, a thick film is required for high-speed driving due to its high density, and the etching time is long, but it can move more than silicon.

That is, since the entire active layer 2 except for the reflecting surface is made of only one of the above materials, unlike the impact resistance improvement described in Patent Document 1, the resonance frequency is increased and the deflection angle is increased. There exists an effect which is not described in Patent Document 1.

In the above simulation, it is possible to achieve a higher speed and a larger movable area than silicon by using a material for the active layer 163 that has a higher fracture toughness, a higher elastic limit, and a higher Young's modulus than silicon in the second axis direction of FIG. Although the results are shown, the same can be said in the case of driving by resonance in the first axis direction of FIG. 15 as well. Therefore, by using a material having a higher fracture toughness, a higher elastic limit, and a higher Young's modulus than silicon for the active layer 163, it is possible to increase the speed in two axial directions and expand the movable region.

Also, the simulation results for pure silicon carbide, alumina, sapphire, silicon nitride, zirconia, and diamond have been shown above. However, if it is a compound that uses them as the main material and has higher fracture toughness, higher elastic limit, and higher Young's modulus than silicon, it can be used for the movable device 13 . Here, the main material refers to a main material, and is a material formed by adding other materials so as not to impair the fracture toughness, elastic limit, or Young's modulus of the original material.

Specific examples of the above compounds include silicon/silicon carbide composite materials, ruby, mullite, spinel, sialon, cubic zirconia, zircon, polycrystalline diamond, cermet, and the like.

Silicon/silicon carbide composites have a fracture toughness of 3 MPa/√m, an elastic limit of 300-420 MPa, and a Young's modulus of 280-350 GPa. Ruby has a fracture toughness of 5 MPa/√m, an elastic limit of 689 MPa, and a Young's modulus of 470 GPa. Mullite has a fracture toughness of 7 MPa/√m, an elastic limit of 280 MPa, and a Young's modulus of 210 GPa.

Spinel has a fracture toughness of 1.7 MPa/√m, an elastic limit of 400 MPa, and a Young's modulus of 440 GPa. Sialon has a fracture toughness of 6-7 MPa/√m, an elastic limit of 980-1200 MPa, and a Young's modulus of 300-330 GPa. Cubic zirconia has a fracture toughness of 7 MPa/√m, an elastic limit of 711 MPa, and a Young's modulus of 210 GPa.

Zircon has a fracture toughness of 2.6 MPa/√m, an elastic limit of 320 MPa, and a Young's modulus of 330 GPa. Polycrystalline diamond has a fracture toughness of 9.5 MPa/√m, an elastic limit of 1100-2600 MPa, and a Young's modulus of 776-920 GPa. Cermet has a fracture toughness of 440 MPa/√m, an elastic limit of 1470 MPa, and a Young's modulus of 440 GPa.

The mirror section 101, the first support section 120, and the second support section 140 have a fracture toughness of 3 MPa/√m or more and 7 MPa/√m or less, an elastic limit of 525 MPa or more and 2930 MPa or less, and a Young's modulus of 210 GPa or more and 1050 GPa or less. Preferably. By satisfying these requirements, it is possible to increase the frequency and increase the contact angle. Furthermore, by satisfying this condition, it is possible to suppress dynamic surface deformation of the reflecting mirror surface caused by the movement of the movable portion.

In this way, all of the active layer 2 except for the reflective surface is made of silicon carbide, alumina, sapphire, silicon nitride, zirconia, diamond, or the like, which have higher fracture toughness, higher elastic limit, and higher Young's modulus than silicon. By using only one of the compounds as materials, it is possible to increase the speed in two axial directions and expand the movable area.

[Second embodiment]
2nd Embodiment shows the example of a movable device different from 1st Embodiment. In addition, in the second embodiment, the description of the same components as those of the already described embodiment may be omitted.

FIG. 24 is a plan view illustrating a movable device according to the second embodiment; A movable device 13A shown in FIG. 24 is an optical deflection element capable of optical deflection only in one axial direction. The movable device 13A is, for example, an optical scanner, and more specifically, for example, a MEMS scanner.

13 A of movable apparatuses have the movable part 144 which has the reflecting mirror 145, and a pair of meandering beam part 146 which supports the movable part 144 on the both sides of the movable part 144. As shown in FIG. Each meandering beam portion 146 has one end fixed to the support substrate 143 and the other end connected to the movable portion 144 .

The serpentine beam portion 146 and the support substrate 143 preferably have a silicon layer or a laminated portion in which a silicon oxide layer is formed on a silicon layer.

In each meandering beam portion 146, first piezoelectric members 147a and second piezoelectric members 147b are alternately arranged to form a meandering pattern through a plurality of folded portions. Voltage signals having opposite phases are applied to the first piezoelectric member 147a and the second piezoelectric member 147b adjacent to each other, and the meandering beam portion 146 warps in the Z direction.

The first piezoelectric member 147a and the second piezoelectric member 147b, which are adjacent to each other, bend in opposite directions. The bending in the opposite direction is accumulated, and the movable part 144 having the reflecting mirror 145 reciprocates about the rotation axis A as the rotation center. That is, in the movable device 13A, the reflecting mirror 145 performs optical scanning along one axis (X direction).

A large rotation angle can be obtained at a low voltage by applying a sine wave having a drive frequency matching the mirror resonance mode with the rotation axis A as the rotation center in opposite phases to the first piezoelectric member 147a and the second piezoelectric member 147b. can be done.

Regarding the second embodiment, the same can be said for the movable device 13 according to the first embodiment when it is driven by resonance. That is, in the movable device 13A, the support substrate 143, the movable portion 144, and the meandering beam portion 146 are made of a material having a higher fracture toughness, a higher elastic limit, and a higher Young's modulus than silicon. can be increased.

The movable portion 144, the meandering beam portion 146, and the support substrate 143 have a fracture toughness of 3 MPa/√m or more and 7 MPa/√m or less, an elastic limit of 525 MPa or more and 2930 MPa or less, and a Young's modulus of 210 GPa or more and 1050 GPa or less. preferable. By satisfying these requirements, it is possible to increase the frequency and increase the contact angle. Furthermore, by satisfying this condition, it is possible to suppress dynamic surface deformation of the reflection mirror surface caused by the movement of the movable portion.

Although the preferred embodiments and the like have been described in detail above, the present invention is not limited to the above-described embodiments and the like, and various modifications and substitutions can be made to the above-described embodiments and the like without departing from the scope of the claims. can be added.

For example, in a vibrating gyroscope (angular rate sensor), the moving part may be made of a material that has a higher fracture toughness, a higher elastic limit, and a higher Young's modulus than silicon. As a result, in a vibrating gyroscope (angular rate sensor), a high Q value can be achieved due to the high Young's modulus, and in addition to achieving higher sensitivity and higher S/N than silicon, high fracture toughness and high elastic limit can be achieved. By being, it is possible to improve the impact resistance of the movable portion.

In addition, by forming the moving part from a material that has higher fracture toughness, higher elastic limit, and higher Young's modulus than silicon, not only is it possible to achieve both high speed and a large moving range, but also impact resistance and dynamic deformation of the moving part. It also has the effect of suppressing

REFERENCE SIGNS LIST 1 model 2 active layer 3 support layer 4 movable mirror section 5 beam section (torsion bar)
6 Piezoelectric Part 7 Diaphragm Part 8 Reinforcing Rib 10 Optical Scanning System 11 Control Device 12, 12b Light Source Device 13, 13A Movable Device 14 Reflecting Surface 15 Scanned Surface 25 Light Source Device Driver 26 Movable Device Driver 30 Control Section 31 Drive Signal Output unit 50 Laser headlamp 51 Mirror 52 Transparent plate 60 Head mount display 60a Front 60b Temple 61 Light guide plate 62 Half mirror 63 Wearer 101 Mirror unit 102 Mirror unit substrate 110a, 110b First driving unit 111a, 111b Torsion bar 112a, 112b First Piezoelectric Driving Section 120 First Supporting Sections 130a, 130b Second Driving Sections 131a to 131f and 132a to 132f Second Piezoelectric Driving Section 140 Second Supporting Section 144 Movable Section 145 Reflecting Mirror 146 Meandering Beam Section 143 Support Substrate 147a First Piezoelectric Driving Section 140 Piezoelectric member 147b Second piezoelectric member 150 Electrode connecting portion 161 Supporting layer 162 Silicon oxide layer 163 Active layer 170A, 170B Piezoelectric drive unit group 201 Lower electrode 202 Piezoelectric unit 203 Upper electrode 400 Automobile 500 Head-up display device 650 Laser printer 700 Lidar device 702 target object 801 package member 802 attachment member 803 transparent member

JP 2017-102232 A

Claims (16)

An optical deflection element that deflects light incident on the reflecting surface by rotating a movable part having a reflecting surface,
a first drive unit connected to the movable unit for driving the movable unit about a first axis;
a first supporting portion that supports the movable portion and the first driving portion;
The first drive section includes a beam section that rotatably supports the movable section,
The movable part is composed of a first layer and a second layer,
The first layer has the reflective surface,
All of the first layer except for the reflecting surface and the beams are made of silicon carbide, alumina, sapphire, silicon nitride, zirconia, diamond, or compounds containing these as main materials. element. 2. The optical deflection element according to claim 1 , wherein said second layer is formed with ribs for reinforcing said reflecting surface, and is made of either silicon or silicon with an oxide film. a second driving section connected to the first supporting section for driving the movable section and the first supporting section around a second axis perpendicular to the first axis;
3. The optical deflection element according to claim 1, further comprising a second supporting portion that supports the second driving portion. 4. The optical deflection element according to claim 3 , wherein the first supporting portion and the second supporting portion have a silicon layer or a lamination portion in which a silicon oxide layer is formed on a silicon layer. The movable portion, the first support portion, and the second support portion each have a fracture toughness of 3 MPa/√m or more and 7 MPa/√m or less, an elastic limit of 525 MPa or more and 2930 MPa or less, and a Young's modulus of 210 GPa or more and 1050 GPa or less. Item 5. The optical deflection element according to item 4 . An optical deflection element that deflects light incident on the reflecting surface by rotating a movable part having a reflecting surface,
Having a pair of meandering beams supporting the movable part on both sides of the movable part,
one end of each of the meandering beam portions is fixed to a support substrate and the other end is connected to the movable portion;
The reflecting surface performs uniaxial optical scanning,
The movable part is composed of a first layer and a second layer,
The first layer has the reflective surface, and all of the first layer excluding the reflective surface and the serpentine beam portion are made of silicon carbide, alumina, sapphire, silicon nitride, zirconia, diamond, or a material thereof. A light deflection element composed only of any one of the compounds. 7. The optical deflection element according to claim 6 , wherein the supporting substrate has a silicon layer or a lamination portion in which a silicon oxide layer is formed on the silicon layer. 8. The movable portion, the meandering beam portion, and the support substrate have a fracture toughness of 3 MPa/√m or more and 7 MPa/√m or less, an elastic limit of 525 MPa or more and 2930 MPa or less, and a Young's modulus of 210 GPa or more and 1050 GPa or less. A light deflection element as described. An optical deflection system comprising the optical deflection element according to any one of claims 1 to 8 . An optical scanning system comprising the optical deflection element according to any one of claims 1 to 8 . An image projection device comprising the optical deflection element according to any one of claims 1 to 8 . A head-up display comprising the optical deflection element according to any one of claims 1 to 8 . A laser headlamp comprising the light deflection element according to any one of claims 1 to 8 . A head mounted display comprising the optical deflection element according to any one of claims 1 to 8 . An object recognition device comprising the optical deflection element according to any one of claims 1 to 8 . A moving object comprising at least one of the head-up display according to claim 12 , the laser headlamp according to claim 13 , and the object recognition device according to claim 15 .

Images