JP2003005123A - Optical scanner and driving method for optical scanner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the cost of an optical scanner and to place the scanner continuously in stable operation. SOLUTION: The laser light emitted by a laser diode 10 is reflected by a mirror part 20 supported in a cantilever state by a cantilever beam part 32 to irradiate an object. When a scan is made with the laser light by vibrating the mirror part 20, 1st and 2nd piezoelectric elements 21a and 21b detect the bending deformation quantity and torsional deformation quantity of the mirror part 20. According to an operation frequency and an operation amplitude computed from the detection results, a magnetic field applying means 22 which drives and vibrats the mirror part 20 is driven. At this time, the resonance frequency of the mirror frequency is tuned to a specified value according to the vibration frequency of the mirror part 20 computed from the deformation quantities detected when 1st and 2nd interrupters 46a and 46b intermittently drive the magnetic field applying means 22 and stopped driving and vibrating them.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention reflects the light emitted from a light source through an elastically deformable member by a mirror portion supported in a cantilever shape to irradiate an object and vibrates the mirror portion. The present invention relates to an optical scanner device that scans the light to be applied to the object by doing so, and a driving method of such an optical scanner device.

[0002]

2. Description of the Related Art Conventionally, a laser beam emitted from a light source is
An optical scanner device for irradiating an object while scanning in the dimensional direction has been proposed, and is applied to, for example, a two-dimensional laser radar for vehicles. 2D laser radar for vehicles
The relationship between the emitted laser light from the optical scanner device and the reflected return light from the object is detected by irradiating the object around the vehicle with laser light using the optical scanner device and detecting the reflected return light from this object. Based on the above, the distance to the object, the horizontal direction, the horizontal angle, and the like are detected. If such a two-dimensional laser radar for a vehicle is mounted on a vehicle, the situation around the vehicle can be appropriately and surely grasped, and therefore, it has been attracting attention as a technique for improving safety when the vehicle is running.

As a conventional optical scanner device, a configuration disclosed in, for example, Japanese Patent Application Laid-Open No. 9-101474 is known. This conventional example relates to a two-dimensional optical scanner device driven by resonance, in which two mutually-supporting beam-like torsional vibrating beams which are orthogonal to each other are arranged around a reflection mirror. Then, by arranging a piezoelectric actuator at the base of these two torsion vibrating beams that function as a vibration axis, and by applying an AC voltage corresponding to the resonance frequency of bending and torsion of the vibration axis to the piezoelectric actuator by combining them, Bending and torsional vibrations are applied to the reflecting mirror at the same time, which enables two-dimensional scanning.

Further, in this conventional example, a piezoelectric sensor is arranged at the base of the torsional vibration beam. The piezoelectric sensor detects the deflection angle of the reflection mirror as a stress signal, applies the stress signal to the self-excited oscillation circuit, amplifies the feedback to the piezoelectric actuator, and feeds back the oscillation frequency of the piezoelectric actuator. The oscillation natural frequency is matched with the torsional natural frequency, and the oscillation amplitude is controlled to a constant value. This makes it possible to stably vibrate the reflecting mirror in response to changes in the damping coefficient and the resonance frequency due to changes in temperature, etc.
It is possible to realize dimensional scanning.

[0005]

By the way, in the above-mentioned conventional optical scanner device, the reflection mirror is supported by two double-supported beams of bending and twisting, and the vibration of the twisting of these two double-supporting beams is supported. The structure is used. Therefore, the amplitude (that is, the deflection angle) of the beam is uniformly attenuated in the frequency range before and after the resonance frequency, and it is easy to obtain good resonance characteristics. Therefore, a simple control circuit such as a self-oscillation circuit can be used to continue the resonance of the reflection mirror while maintaining the frequency matched with the natural frequency of the beam.

However, since the optical scanner device in the above-mentioned conventional example has a structure in which the reflection mirror is supported by two double-supported beams, the device configuration is complicated,
There is a limit to the cost reduction.

Therefore, as a method of simplifying the apparatus structure and realizing a large cost reduction, for example, a reflecting mirror is supported by a single cantilever, and the cantilever vibrates in the bending direction and the torsional direction, respectively. By doing so, a method of performing two-dimensional scanning has been considered. However, in this case, when trying to obtain a large torsional vibration in response to a wide range of scanning, a phenomenon called a so-called hard spring effect occurs as shown in FIG. 16, and a frequency range before and after the resonance frequency is generated. However, there was a problem in that the damping characteristics of the amplitude of the beam became asymmetric, resulting in an extremely non-linear vibration mode. It is difficult to stably operate such resonance vibration having a strong non-linearity by feedback control using a self-excited oscillation circuit.

Therefore, in the optical scanner device in the conventional example, when a disturbance such as a vibration including a high frequency component occurs, the feedback control system diverges, so that the optical scanner device vibrates in a frequency range slightly higher than the resonance frequency. Resonance may stop when the control circuit operates. Further, when the operation is restarted after the resonance is stopped, the feedback control system tends to have an unstable resonance mode due to an excessive response.

Therefore, when the conventional optical scanner device is applied to, for example, a two-dimensional laser radar for a vehicle, the operation is likely to be unstable due to the vibration of the vehicle including high frequency components, and the resonance frequently stops. Therefore, it is difficult to obtain sufficient reliability.

On the other hand, in the optical scanner device, for example, in order to drive the beam that supports the reflection mirror, a magnetostrictive film that generates a stress that changes according to a magnetic field applied from the outside is formed on the back surface of the beam. It is possible to
In this case, as shown in FIG. 17, the effect of the hysteresis generated in the magnetostrictive film becomes remarkable.

Specifically, for example, when the operation is restarted after the resonance is stopped by shifting to a frequency range higher than the resonance frequency, a reflection mirror from a frequency much lower than the original resonance frequency to the resonance frequency. It is necessary to adopt a method of sequentially sweeping the frequency that drives the magnetic field or a method of resuming the resonance after reversing the magnetic moment inside the magnetostrictive film to the state before the resonance stopped by applying a DC magnetic field. . However, with either method, the vibration operation of the reflection mirror is temporarily stopped.

Therefore, it is difficult to apply such an optical scanner device to a two-dimensional laser radar for a vehicle which is required to constantly detect an object around the vehicle.

The present invention has been made in view of the above-mentioned conventional circumstances, and realizes an optical system which simplifies the apparatus configuration and realizes a significant cost reduction, and which is capable of continuously performing stable scanning. It is an object of the present invention to provide a scanner device and a method for driving such an optical scanner device.

[0014]

According to a first aspect of the present invention, light emitted from a light source is reflected by a mirror portion supported in a cantilever shape via an elastically deformable member to illuminate an object. At the same time, in an optical scanner device that scans the light irradiating the object by vibrating the mirror unit, a driving unit that deforms the elastically deformable member to vibrate the mirror unit, and the driving unit is intermittently provided. Drive control means for operating, deformation amount detection means for detecting the deformation amount of the elastic deformation member, and frequency detection means for processing the signal output from the deformation amount detection means to detect the vibration frequency of the mirror section. And adjusting the operating frequency of the driving means based on the vibration frequency detected by the frequency detecting means when the operation of the driving means is stopped by the drive control means. And by and is characterized in that it comprises a frequency tuning means for tuning the resonant frequency of the mirror portion to a predetermined value.

The invention described in claim 2 is the same as claim 1.
In the optical scanner device according to, the frequency tuning means subtracts a predetermined value from the value of the vibration frequency detected by the frequency detecting means when the operation of the drive means is stopped by the drive control means, The operating frequency of the drive means is adjusted based on the subtracted frequency value.

The invention described in claim 3 is the same as claim 1
Or the optical scanner device according to 2, further comprising pulse voltage applying means for applying a pulse voltage to the driving means at least when the power is turned on, and the frequency tuning means applies the pulse voltage to the driving means. It is characterized in that the operating frequency of the drive means is adjusted based on the vibration frequency detected by the frequency detection means at a time point after a lapse of a predetermined time.

The invention according to claim 4 is the same as claim 1.
The optical scanner device according to claim 1, wherein the drive unit includes a first drive unit that deforms the elastically deformable member in a twisting direction, and a second drive unit that deforms the elastically deformable member in a bending direction, The deformation amount detection means includes a torsional deformation amount detection unit that detects a torsional deformation amount of the elastic deformation member, and a bending deformation amount detection unit that detects a bending deformation amount of the elastic deformation member, and the frequency detection unit includes A torsion frequency detection unit that processes a signal output from the torsion deformation amount detection unit to detect a torsion vibration frequency, and a bending frequency that processes a signal output from the bending deformation amount detection unit to detect a bending vibration frequency. A detection unit, wherein the driving unit deforms the elastically deformable member in a twisting direction and a bending direction, respectively, so that light from a light source is two-dimensionally scanned with respect to the object. It is.

The invention according to claim 5 is the invention according to claim 4
In the optical scanner device described in the paragraph (1), the frequency tuning unit drives the first drive based on a torsional vibration frequency detected by the torsional frequency detecting unit when the operation of the drive unit is stopped by the drive control unit. By adjusting the operating frequency of the section, the torsional resonance frequency of the mirror section is tuned to a predetermined value, and the drive control means is configured to adjust the first resonance frequency based on the output from the frequency tuning means.
In addition to controlling the operation of the driving unit, the operation of the second driving unit is controlled based on the signal generated by the self-excited oscillation circuit.

The invention according to claim 6 is the same as claim 4
Alternatively, in the optical scanner device according to the fifth aspect, the frequency tuning unit has a predetermined value from the value of the torsional vibration frequency detected by the torsional frequency detecting unit when the operation of the driving unit is stopped by the drive control unit. Is subtracted, and the operating frequency of the first drive unit is adjusted based on the value of the subtracted frequency, whereby the torsional resonance frequency of the mirror unit is tuned to a predetermined value. .

The invention according to claim 7 is the same as that according to claim 4.
The optical scanner device according to any one of claims 1 to 6, further comprising a pulse voltage applying unit that applies a pulse voltage to the first driving unit at least when the power is turned on, and the frequency tuning unit includes the first tuning unit. The operating frequency of the first drive unit is adjusted based on the torsional vibration frequency detected by the torsional frequency detection unit at a time point after a predetermined time has elapsed since the pulse voltage was applied to the drive unit. It is a thing.

Further, in the invention described in claim 8, the light emitted from the light source is reflected by a mirror portion supported in a cantilever shape via an elastically deformable member to illuminate the object, and the mirror is also provided. In a driving method of an optical scanner device for scanning light irradiating the object by vibrating a section, a mirror section intermittent driving step of intermittently deforming and driving the elastic deformation member to vibrate the mirror section, A vibration frequency detecting step of detecting a vibration frequency of the mirror section based on the deformation amount of the elastically deformable member, and an operating frequency of the mirror section is adjusted based on the vibration frequency detected when the driving of the mirror section is stopped. By doing so, there is provided a frequency tuning step of tuning the resonance frequency of the mirror portion to a predetermined value.

The invention described in claim 9 is the same as claim 8.
In the method of driving the optical scanner device according to the item (1), in the frequency tuning step, a predetermined value is subtracted from the value of the vibration frequency detected when the driving of the mirror unit is stopped, and the subtracted frequency value is obtained. The operating frequency of the mirror section is adjusted based on the above.

According to a tenth aspect of the present invention, there is provided an optical scanner device driving method according to the eighth or ninth aspect, wherein:
At least when the power is turned on, pulse drive the mirror unit,
The method may further include a pulse driving step of adjusting an operating frequency of the mirror unit based on a vibration frequency detected after a predetermined time has elapsed after the mirror unit is pulse-driven.

The invention according to claim 11 is the method for driving an optical scanner device according to claim 8, wherein in the intermittent driving step of the mirror portion, the elastically deformable member is respectively twisted and bent. In addition to deforming, in the vibration frequency detecting step, the torsional vibration frequency and the bending vibration frequency are respectively detected based on the torsional deformation amount and the bending deformation amount of the elastically deformable member, and the light from the light source is emitted from the object. It is characterized in that it is two-dimensionally scanned.

According to a twelfth aspect of the present invention, in the method of driving the optical scanner device according to the eleventh aspect, in the frequency tuning step, the vibration frequency detecting step is performed when the driving of the mirror section is stopped. By adjusting the operating frequency of the mirror section in the torsional direction based on the torsional vibration frequency detected in the above, the torsional resonance frequency of the mirror section is tuned to a predetermined value and a signal generated by a self-excited oscillation circuit. Based on the above, the operating frequency in the bending direction of the mirror portion is controlled.

According to a thirteenth aspect of the present invention, in the method of driving the optical scanner device according to the eleventh or twelfth aspect, in the frequency tuning step, the vibration frequency when the driving of the mirror section is stopped. Subtract a predetermined value from the torsional vibration frequency detected in the detection step,
It is characterized in that the torsional resonance frequency of the mirror portion is tuned to a predetermined value based on the value of the subtracted frequency.

According to a fourteenth aspect of the present invention, in the method of driving the optical scanner device according to any one of the eleventh to thirteenth aspects, at least when the power is turned on, the mirror portion is pulse-driven in the twisting direction to cause the mirror It is characterized by further comprising a pulse driving step of adjusting the operating frequency of the mirror portion in the twisting direction based on the torsional vibration frequency detected after a predetermined time has elapsed since the portion was pulse-driven.

[0028]

According to the optical scanner device of the first aspect, the driving means for vibrating the mirror portion is intermittently driven by the drive control means, and when the operation of the driving means is stopped, the frequency detecting means is used. By adjusting the operating frequency of the drive means based on the detected vibration frequency, even when the hard spring effect occurs in the elastically deformable member that supports the mirror portion, for example, a magnetostrictive film with a relatively small hysteresis is driven. By using it as a means, it is possible to always maintain stable resonant operation in response to temperature changes. In addition, since the mirror portion is supported in a cantilever shape, the device configuration can be simplified and the cost can be reduced. Therefore, particularly when used in a laser radar for a vehicle, it is possible to effectively prevent the stop of the scanning operation due to the vibration of the vehicle, improve the reliability of the device, and improve the safety during traveling of the vehicle. You can secure enough.

According to the optical scanner device of the second aspect, in addition to the effect of the first aspect, a sudden disturbance vibration is applied by using a magnetostrictive film having a relatively small hysteresis as the driving means. Even if the operating frequency of the driving means can be adjusted based on the value of the frequency obtained by subtracting a predetermined value from the value of the vibration frequency detected by the frequency detecting means, the influence of this disturbance vibration can be effectively suppressed. As a result, stable resonance operation can be maintained. Therefore, particularly when used in a laser radar for a vehicle, it is possible to more effectively reduce the influence of the vibration of the vehicle and more appropriately prevent the inconvenience that the operation of the device is stopped.

Further, according to the optical scanner device of the third aspect, in addition to the effect of the first or second aspect, the extreme temperature such as when the ambient temperature around the device is extremely high or extremely low is used. Even in an operating environment, the resonance operation of the mirror section can be reliably and stably performed when the power is turned on. Therefore, the reliability of the device can be sufficiently ensured even when the device is used by being installed in a vehicle provided in a tropical region or a cold region.

According to the optical scanner device of the fourth aspect, in addition to the effect of the first aspect, the mirror portion can be driven and controlled in the twisting direction and the bending direction, respectively, and the light from the light source is targeted. Two-dimensional scanning can be performed on an object.

According to the optical scanner device of the fifth aspect, in addition to the effect of the fourth aspect, the detected vibration is only for the torsional vibration in which the influence of the hard spring effect and the magnetic hysteresis becomes remarkable. Tuning control based on frequency can be performed, and feedback control can be performed with respect to bending vibration by an inexpensive self-oscillation circuit. Therefore, the scale of the circuit mounted on the device can be reduced, the size and weight can be reduced, and the cost can be further reduced.

According to the optical scanner device of the sixth aspect, in addition to the effect of the fourth or fifth aspect, when a rapid disturbance vibration is applied by using a magnetostrictive film having a relatively small hysteresis as a driving means. However, since the operating frequency of the driving means can be adjusted based on the frequency value obtained by subtracting a predetermined value from the vibration frequency value detected by the frequency detecting means, the effect of this disturbance vibration is effective. Therefore, stable resonance operation can be maintained. Therefore, particularly when it is used for a two-dimensional laser radar for a vehicle, it is possible to effectively reduce the influence of the vibration of the vehicle and more appropriately prevent the inconvenience that the operation of the device is stopped.

According to the optical scanner device of the seventh aspect, in addition to the effect of any of the fourth to sixth aspects, for example, when the ambient temperature around the device is extremely high or extremely low. Even under such extreme operating environment, the resonance operation of the mirror section can be reliably and stably performed when the power is turned on. Therefore, the reliability of the device can be sufficiently ensured even when it is mounted on a vehicle provided in a tropical region or a cold region, for example.

According to the driving method of the optical scanner device according to the eighth aspect, the mirror section is intermittently oscillated and driven based on the vibration frequency detected when the driving of the mirror section is stopped. Even if the elastically deformable member that supports the mirror section has a hard spring effect by adjusting the frequency, for example, by driving the mirror section with a magnetostrictive film having a relatively small hysteresis, it is possible to respond to the temperature change. It is possible to maintain stable resonance operation at all times. In addition, since the mirror portion is supported in a cantilever shape, the device configuration can be simplified and the cost can be reduced. Therefore, particularly when the optical scanner device is used for a laser radar for a vehicle, it is possible to prevent the stop of the scanning operation due to the vibration of the vehicle, and to improve the reliability and safety of the optical scanner device when the vehicle is traveling. You can secure enough.

Further, according to the driving method of the optical scanner device of the ninth aspect, in addition to the effect of the eighth aspect, abrupt disturbance vibration is applied by driving the mirror portion by the magnetostrictive film having a relatively small hysteresis. Even if it is, the operating frequency of the mirror unit can be adjusted based on the value of the frequency obtained by subtracting the predetermined value from the value of the detected vibration frequency, thus suppressing the influence of this disturbance vibration, It is possible to maintain stable resonance operation. Therefore, particularly when the optical scanner device is used in a laser radar for a vehicle, it is possible to reduce the influence of the vibration of the vehicle and more appropriately prevent the inconvenience that the operation of the optical scanner device is stopped.

According to the optical scanner device driving method of the tenth aspect, in addition to the effect of the eighth or ninth aspect, for example, when the ambient temperature around the device is extremely high or extremely low. Even under such extreme operating environment, the resonance operation of the mirror section can be reliably and stably performed when the power is turned on. Therefore, even when the optical scanner device is used by being mounted on a vehicle provided in, for example, a tropical region or a cold region, the reliability of the optical scanner device can be sufficiently ensured.

Further, according to the driving method of the optical scanner device of the eleventh aspect, in addition to the effect of the eighth aspect, the mirror portion can be driven and controlled in the twisting direction and the bending direction, respectively, and the light source The light can be two-dimensionally scanned with respect to the object.

According to the driving method of the optical scanner device of the twelfth aspect, in addition to the effect of the eleventh aspect, only the torsional vibration, which is significantly affected by the hard spring effect and the magnetic hysteresis, Tuning control based on the detected vibration frequency can be performed, and feedback control by an inexpensive self-excited oscillation circuit can be performed on bending vibration. Therefore, it is possible to reduce the scale of the circuit mounted on the optical scanner device, reduce the size and weight of the optical scanner device, and realize further cost reduction.

According to the driving method of the optical scanner device of the thirteenth aspect, in addition to the effect of the eleventh or twelfth aspect, the magnetostrictive film having a relatively small hysteresis drives the mirror portion to cause a sudden disturbance vibration. Even if the vibration is added, the operating frequency of the mirror part can be adjusted based on the frequency value obtained by subtracting the predetermined value from the detected vibration frequency value, so the effect of this disturbance vibration is effective. Therefore, stable resonance operation can be maintained. Therefore, particularly when the optical scanner device is used for a two-dimensional laser radar for a vehicle, it is possible to effectively reduce the influence of the vibration of the vehicle and more appropriately prevent the inconvenience that the operation of the optical scanner device is stopped. You can

According to the driving method of the optical scanner device of the fourteenth aspect, in addition to the effect of any one of the eleventh to thirteenth aspects, for example, when the ambient temperature around the optical scanner device is extremely high or extremely high. Even under an extreme operating environment such as a low temperature, the resonant operation of the mirror portion can be reliably and stably performed when the power is turned on. Therefore, the reliability of the optical scanner device can be sufficiently ensured even when the optical scanner device is mounted on a vehicle provided in a tropical region or a cold region.

[0042]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. Below, the example which applied this invention to the two-dimensional laser radar apparatus for vehicles is demonstrated concretely.

(First Embodiment) As shown in FIG. 1, a two-dimensional laser radar device shown as a first embodiment includes a laser diode 10 for emitting a laser beam for illuminating an object 100, and a laser diode 10 for emitting the laser beam. A laser diode drive circuit 11 that drives the laser diode 10 and a control circuit 12 that outputs the emission timing of the laser diode 10 to the laser diode drive circuit 11 are provided.

Further, in this two-dimensional laser radar device, the laser light emitted from the laser diode 10 is applied to the object 1
The photodetector 13 receives the return light reflected by 00 and returns, and the light receiving circuit 14 that performs various signal processing on the output signal from the photodetector 13. The light receiving circuit 14 outputs a predetermined signal to the control circuit 12 based on the output signal from the photo detector 13. Then, the control circuit 12 reflects the laser light from the laser diode 10 and then reflects it on the object 100 in accordance with the output signal from the light receiving circuit 14, and then the photo detector 1
Based on the propagation delay time until detected by 3
The position information of the target object 100 such as the distance to the target object 100 existing around the vehicle and the angles in the horizontal and vertical directions is calculated. Further, the control circuit outputs the light emission timing of the laser diode 10 to the laser diode drive circuit 11 based on the calculated position information of the object 100.

Further, the two-dimensional laser radar device is scanned by the scanner unit 15 which reflects the laser light emitted from the laser diode 10 in the horizontal and vertical directions and scans it in a two-dimensional manner, and the scanner unit 15. A reflection mirror 16 that reflects the laser light and irradiates the front of the vehicle, for example.
With.

As shown in FIGS. 1 to 3, the scanner section 15 includes a mirror section 20 that reflects laser light, and a magnetostrictive element (FIGS. 1 to 3) that drives the mirror section 20 in a twisting direction and a bending direction. (Not shown in the figure), and the mirror unit 2
First to detect the torsional deformation amount and the bending deformation amount of 0 respectively
Piezoresistive element 21a and second piezoresistive element 21
b and a magnetic field applying means 22 for applying an external magnetic field to the magnetostrictive element.

In addition, this two-dimensional laser radar device includes the first piezoresistive element 21a and the second piezoresistive element 2
A drive control circuit 23 is provided which detects the torsional vibration frequency and the bending vibrational frequency of the mirror section 20 based on the output signal from 1b and controls the external magnetic field applied by the magnetic field applying means 22 according to the detection result. Further, in this two-dimensional laser radar device, the drive control circuit 23 has the control circuit 12
The control circuit 12 controls the operation of the entire apparatus.

Next, the structure of the scanner section 15 will be described in detail with reference to FIGS.

As shown in FIGS. 2 and 3, the scanner section 15 has an outer shape formed into a substantially rectangular flat plate shape, and is formed in a U-shape by processing a silicon wafer by various micromachining processing techniques. The mirror portion 20 is divided by the slit portion 30 and the frame portion 31 surrounding the mirror portion 20. One end of the mirror portion 20 is formed integrally with the frame portion 31, and is supported by the frame portion 31 in a cantilever shape. The boundary portion between the mirror portion 20 and the frame portion 31 (hereinafter referred to as the cantilever beam portion 32) is elastically deformable in the twisting direction and the bending direction.

The mirror section 20 is formed, for example, by applying a highly reflective coating on the main surface of a silicon wafer by vapor deposition of aluminum, and has a sufficient reflectance with respect to the emitted laser light.

Further, a magnetostrictive element (not shown) is formed in a thin film shape on the surface of the cantilever portion 32 opposite to the surface on which the mirror portion 20 is formed. This magnetostrictive element is formed under a predetermined magnetic field, so that the easy axis of magnetization is set in a direction having an inclination angle of approximately 22.5 degrees with respect to the direction of arrow A shown in FIG. 2, for example.

The cantilever portion 32 has a first piezoresistive element 2 for detecting displacements of the mirror portion 20 in the bending direction and the twisting direction with respect to the direction of arrow D shown in FIG.
1a and a second piezoresistive element 21b are formed. These first and second piezoresistive elements 21a, 21
The output signal from b is output to the outside via the electrode portion 33 formed at the end of the frame portion 31.

As shown in FIG. 3, the scanner section 15 has the magnetic field applying means 22 arranged around the outer frame section 34 with the frame section 31 attached to the outer frame section 34. . Note that FIG. 3A is a plan view in a state where the scanner unit 15 is attached to the outer frame unit 34, and FIG. 3B is a side view in this state.

The magnetic field applying means 22, under the control of the drive control circuit 23, is an alternating magnetic field in which two components of the respective resonance frequencies in the bending direction and the twisting direction in the mirror portion 20 with respect to the arrow D direction shown in FIG. Is applied to the magnetostrictive element.

The scanner section 15 constructed as described above
Means that the magnetostrictive element is driven by applying an alternating magnetic field by the magnetic field applying means 22, and the cantilever portion 32 moves in the bending direction shown by the arrow B in FIG. 2 and in the twisting direction shown by the arrow C in FIG. Deform. As a result, the mirror section 20 vibrates in the bending direction and the twisting direction. The vibration of the mirror section 20 is detected by the first and second piezoresistive elements 21 a and 21 b formed on the cantilever section 32 and output to the drive control circuit 23.

Here, a specific configuration example of the scanner section 15 will be described. The outer shape of the mirror portion 20 supported in a cantilever shape by the cantilever portion 32 is, for example, 10 mm in length, 5 mm in width, and about 20 μm in thickness. The mirror section 20 has a torsional resonance frequency of 2 kHz and a bending resonance frequency of 200 Hz, for example. Further, the displacement angle of the mirror portion 20 with respect to the frame portion 31 at each resonance frequency is, for example, 5 degrees in the twisting direction and 20 degrees in the bending direction. These displacement angles can be freely controlled according to the alternating magnetic field applied by the magnetic field applying means 22.

In the above description, the inclination angle of the easy axis of magnetization of the magnetostrictive element is set to 22.5 degrees, but it is not limited to this value. However, from the mechanical characteristics of the cantilever portion 32, it is desirable that the inclination angle of the easy axis of magnetization of the magnetostrictive element be 45 degrees with respect to torsional vibration, and the inclination angle be 0 degrees with respect to bending vibration. Is desirable. In this example, since the mirror portion 20 is vibrated in both the twisting direction and the bending direction, it is desirable to select 22.5 degrees which is an intermediate value between 0 degree and 45 degrees.

In the above explanation, the mirror portion 20 is vibrated by the magnetostrictive element formed on the cantilever beam portion 32 and the magnetic field generating means 22. The configuration is not limited to this, and for example, a piezoelectric element may be used, or various driving forces such as Coulomb force may be used.

Further, as shown in FIG. 3, the scanner unit 1
When attaching 5 to the outer frame portion 34, it is desirable to provide various spacers or the like having a predetermined thickness (for example, 3 mm). As a result, even when the mirror section 20 vibrates at a large deflection angle, it is possible to prevent the mirror section 20 from interfering with the outer frame section 34 and other members of the two-dimensional laser radar device. it can.

As the magnetic field applying means 22 described above, for example, a coil formed by winding an enameled wire having a diameter of 0.1 mm 500 times can be used.

Next, an example of a specific circuit configuration of the drive control circuit 23 described above will be described below.

The drive control circuit 23, as shown in FIG.
First and second signal conditioners 41a and 41b for amplifying output signals from the first and second piezoresistive elements 21a and 21b formed in the scanner unit 15, respectively.
And these first and second signal conditioners 41
The signals amplified by a and 41b are respectively input, and the first and second frequency detectors 42 for detecting the bending vibration frequency and the torsional vibration frequency of the mirror section 20 are detected.
a, 42b and the first and second frequency detectors 42
The CPU 4 in which the values of the vibration frequencies detected by a and 42b are input to the input terminal ch1 and the input terminal ch2, respectively.
3 and 3. The CPU 43 is connected to a memory unit 44 that stores a program showing a processing procedure described later. Then, the CPU 43 performs various arithmetic processes according to the value of the input vibration frequency according to the program stored in the memory unit 44 to obtain the voltage value and the frequency value for driving the bending vibration and the torsional vibration of the mirror unit 20, It outputs from the output terminal ch3 and the output terminal ch4, respectively.

The drive control circuit 23 receives the voltage value and the frequency value output from the output terminal ch3 and the output terminal ch4 of the CPU 43, respectively, and outputs the sine wave corresponding to the input signal. 2 oscillators 4
5a, 45b, and the first and second interrupters 4
6a, 46b and the first and second output amplifiers 47a, 4
7b and an adder 48.

The sine waves output from the first and second oscillators 45a and 45b are the first and second interrupters 4 respectively.
First and second output amplifiers 47 via 6a and 46b
a, 47b. First and second output amplifier 4
7 a and 47 b amplify the input sine waves and output the amplified sine waves to the adder 48. The adder 48 adds the sine waves input from the first and second output amplifiers 47 a and 47 b and outputs the added sine waves to the magnetic field applying unit 22. As a result, in the optical scanner device, an alternating magnetic field is applied from the magnetic field applying means 22 to the magnetostrictive element, and the mirror section 20 vibrates in the bending direction and the twisting direction, respectively.

On the other hand, the signals output from the first and second signal conditioners 41a and 41b are the control circuit 1
It is also output to 2. Then, the control circuit 12 detects from which direction or distance the return light detected by the photodetector 13 is reflected, based on the input signal. Accordingly, the two-dimensional laser radar device is capable of detecting positional information regarding the target object 100, such as the distance to the target object 100 and the angles in the horizontal and vertical directions.

Further, the first and second interrupters 46a, 46
b is the output terminal ch5 and the output terminal ch6 of the CPU 43.
The signals output from are input respectively.
According to control from the PU 43, the first and second oscillators 4
The outputs of the sine waves output from 5a and 45b to the first and second output amplifiers 47a and 47b can be appropriately cut off.

Here, an example of the processing by the drive control circuit 23 provided in the two-dimensional laser radar device configured as described above will be specifically described with reference to FIGS. 5 and 6.

When the power of the two-dimensional laser radar device is turned on and the operation is started, in step S10 in FIG. 5, the output terminal ch5 of the CPU 43 is connected to the first interrupter 46.
A signal for cutting off a is output. The vibration amplitude of the mirror section 20 at this point is indicated by time T1 in FIG. After this time T1, a magnetic field for exciting the mirror section 20 only in the torsional direction is applied to the magnetostrictive element from the magnetic field applying means 22, but the mirror section 20 is affected by reverberation resonance before the time T1. While gradually attenuating the amplitude while gradually approaching the bending natural vibration frequency from the frequency,
Continue to vibrate.

Next, in step S11, the CPU 4
3 is a predetermined time (for example, 20 msec) from time T1
Determines whether or not has elapsed. As a result, if the predetermined time has elapsed, the process proceeds to the next step S12, and if not, the determination process of step S11 is repeated.

Here, from step S11 to step S1
Setting the elapsed time until the transition to 2 to 20 msec is the optimum value empirically determined by the inventor of the present invention. Specifically, when the displacement angle of the mirror section 20 is set to 20 degrees at a bending resonance frequency of about 200 Hz,
20 m after the drive in the torsional direction is cut off at time T1
The vibration amplitude of the mirror portion at the time point of sec was about 16 degrees. If a bending angle of 16 degrees is obtained when the drive in the torsional direction is cut off in this way, a horizontal scanning angle of 32 degrees can be secured for the laser light, which is a sufficient horizontal level for a laser radar device for a vehicle. The scan angle can be secured.

On the other hand, when the transition time from step S11 to step S12 in this example is set to be shorter than 20 msec, the transition to the bending natural vibration frequency in the mirror section 20 is not completed, and the erroneous vibration frequency in the next step S12. It causes a problem such as measuring.
Further, if the transition time in this example is set to be longer than 20 msec, the bending angle of the mirror section 20 due to reverberation becomes too small, and the horizontal scanning angle of the laser light cannot be sufficiently secured, so that the detection function of the object 100 can be achieved. Will be restricted.

For the above reasons, in this example,
20 msec was set as the optimum elapsed time for accurately measuring the detection of the bending natural vibration frequency of the mirror section 20 in the next step S12. The vibration damping rate of the mirror section 20 in this example was 20%.

Next, in step S12, the bending natural vibration frequency and the vibration amplitude of the mirror section 20 are detected by the first frequency detector 42a based on the output signal from the first piezoresistive element 21a. The vibration amplitude of the mirror section 20 at this time is shown by time T2 in FIG.
Indicate. The bending natural vibration frequency and vibration amplitude detected at this time are temporarily stored in the memory unit 44 by the CPU 43.

Next, in step S13, the CPU 4
3 calculates the difference by comparing the bending natural vibration frequency and the vibration amplitude detected in step S12 with the initial value recorded in advance in the memory unit 44, and obtains the optimum amplitude value adjusted based on this difference. .

Next, in step S14, the CPU 4
3 outputs the bending natural vibration frequency detected in step S12 and the optimum amplitude value obtained in step S13 to the first oscillator 45a via the output terminal ch3. At this point,
The mirror section 20 vibrates only in the twisting direction by the magnetic field applied by the magnetic field applying means 22.

Next, in step S15, the CPU 4
3 outputs a request to connect the first interrupter 46a via the output terminal ch5. Thereby, the magnetic field applying means 22
Therefore, the alternating magnetic field corresponding to the bending vibration as well as the torsional vibration is applied to the magnetostrictive element, and the mirror unit 20 is
It vibrates in two directions, a twisting direction and a bending direction. The vibration amplitude of the mirror section 20 at this time is shown at time T3 in FIG.

Next, in step S16, the CPU 4
3 outputs a signal for cutting off the second interrupter 46b from the output terminal ch6. In the operation of shutting off the second interrupter 46b described below, the change in the vibration amplitude of the mirror section 20 changes as described above.
Since this is almost the same as the case of shutting off, the vibration amplitude of the mirror section 20 at the time of this step S16 is shown at time T1 used in the above description for convenience in FIG. After this time T1, the magnetic field applying means 22 applies a magnetic field that excites the mirror section 20 only in the bending direction to the magnetostrictive element. However, the mirror section 20 is affected by reverberation resonance before the time T1. Vibration is continued while gradually asymptotically approaching the natural vibration frequency from the frequency and weakening the amplitude.

Next, in step S17, the CPU 4
3 is a predetermined time (for example, 10 msec) from time T1
Determines whether or not has elapsed. As a result, if the predetermined time has elapsed, the process proceeds to the next step S18, and if not, the determination in step S17 is repeated.

Here, from step S17 to step S1
Setting the elapsed time until the transition to 8 to 10 msec is the optimum value empirically determined by the inventor of the present invention. Specifically, the torsional displacement angle of the mirror portion 20 having the outer shape in this example is 5 degrees, and the vibration amplitude of the mirror portion at the time point 10 msec after the driving in the bending direction is interrupted at time T1 is It was about 4 degrees. If a twist angle of 4 degrees is obtained when the drive in the bending direction is cut off in this way, the scan angle of the laser beam is 8 in the vertical direction.
Therefore, it is possible to secure a sufficient vertical scanning angle as a laser radar device for a vehicle.

On the other hand, if the transition time from step S17 to step S18 in this example is set to be shorter than 10 msec, the transition to the torsional natural vibration frequency in the mirror section 20 is not completed, and the erroneous vibration frequency in the next step S18. It causes a problem such as measuring.
Further, if the transition time in this example is set to be longer than 10 msec, the twist angle of the mirror section 20 due to reverberation becomes too small, and the vertical scan angle of the laser light is not sufficiently secured, and the detection function of the target object 100 is not achieved. Will be restricted.

For the above reasons, in this example,
In the next step S17, 10 msec was set as the optimum elapsed time for accurately measuring the detection of the torsional natural vibration frequency of the mirror section 20. The vibration damping rate of the mirror section 20 in this example was 20%.

Next, in step S18, the torsional natural vibration frequency and vibration amplitude of the mirror section 20 are detected by the second frequency detector 42b based on the output signal from the second piezoresistive element 21b. The vibration amplitude of the mirror section 20 at this time is shown by time T2 in FIG.
Indicate. The torsional natural vibration frequency and the vibration amplitude detected at this time are temporarily stored in the memory unit 44 by the CPU 43.

Next, in step S19, the CPU 4
3 compares the torsional natural vibration frequency and vibration amplitude detected in step S18 with the initial value recorded in advance in the memory unit 44 to calculate the difference, and obtains the optimum amplitude value adjusted based on this difference. .

Next, in step S20, the CPU 4
3 outputs the bending natural vibration frequency detected in step S18 and the optimum amplitude value obtained in step S19 to the second oscillator 45b via the output terminal ch4. At this point,
The mirror section 20 vibrates only in the bending direction by the magnetic field applied by the magnetic field applying means 22.

Next, in step S21, the CPU 4
3 outputs a request to connect the second interrupter 46b via the output terminal ch6. Thereby, the magnetic field applying means 22
From this, an alternating magnetic field corresponding to bending vibration and torsional vibration is applied to the magnetostrictive element, and the mirror unit 20 is
It vibrates in two directions, a bending direction and a twisting direction. The vibration amplitude of the mirror section 20 at this time is shown at time T3 in FIG.

Next, in step S22, the CPU 4
3 is a predetermined time (for example, 1
(00 sec) is determined. As a result,
If the predetermined time has passed, the process proceeds to step S1.
After returning to 0, the vibration control in the bending direction and the twisting direction of the mirror section 20 is repeated. It should be noted that when the above-described processing is repeated again in this manner, the above-mentioned times T1, T2, T
The time corresponding to 3 is the time T in FIG.
Shown as 1 ', T2', T3 '. Also, as a result of the judgment,
If the predetermined time has not elapsed, step S
The determination at 22 is repeated.

In the two-dimensional laser radar device of this example, the drive control circuit 23 performs the above-described processing to independently detect the resonance state of the bending vibration and the torsional vibration in the mirror section 20, and detect the resonance state. Based on the result, it is possible to optimally control the vibration of the mirror section 20 in both the bending direction and the twisting direction. As a result, the mirror unit 2
Even when the hard spring effect is generated in the cantilever portion 32 as the elastically deformable member that supports 0, for example, by using a magnetostrictive film having a relatively small hysteresis, it is always stable in response to temperature changes. Resonant operation can be maintained. Further, since the mirror portion 20 is supported in a cantilever shape, the device configuration can be simplified and the cost can be reduced. Therefore,
Particularly when mounted on a vehicle and used, it is possible to prevent the stop of the scanning operation due to the vibration of the vehicle, improve the reliability of the device, and sufficiently secure the safety during traveling. .

In the above example, the case where the laser light is two-dimensionally scanned has been described as the structure in which the mirror portion 20 is oscillated and driven in two directions of bending and twisting. However, the present invention is not limited to this. The invention is not limited to the above, but can be widely applied to various optical scanner devices. For example, the present invention may be applied to a one-dimensional optical scanner device that linearly scans laser light.

(Second Embodiment) Next, as a second embodiment, the first and / or second frequency detectors 42a, 4a will be described.
A two-dimensional laser radar device configured to control the vibration state of the mirror unit 20 based on the frequency value obtained by subtracting a predetermined value from the vibration frequency value detected by 2b will be described.

The two-dimensional laser radar device according to this example is, for example, the first and / or second frequency detectors 42a and 42b and the CPU 43 in the drive control circuit 23 shown in FIG.
It can be realized by arranging a subtraction circuit composed of, for example, various electronic circuits and the like between the two and. It can also be realized by performing a software subtraction process from the frequency values input from the first and second frequency detectors 42a and 42b in the arithmetic processing in the CPU 43. The value to be subtracted is
For example, it may be set by combining electronic elements or the like that form the subtraction circuit, or may be described in a program indicating the processing procedure of the CPU 43.

Here, an example of the processing in the drive control circuit 23 included in the two-dimensional laser radar device of the second embodiment configured to perform the subtraction processing by software will be concretely described with reference to FIG. explain. Note that the processing in the drive control circuit 23 is different from the processing described in the above-described first embodiment only in that the subtraction processing is performed. Therefore, the same processing as the processing described in the first embodiment is performed. Will not be described in detail here.

In the processing by this drive control circuit 23, as shown in FIG.
Step S in which the CPU 43 subtracts a predetermined value (for example, 3 Hz) from the bending vibration frequency detected in step S12.
Have 30. Then, the bending vibration frequency after being subtracted in step S30 is output to the first oscillator 45a in step S14. In addition, before the step S20, C is calculated from the torsional vibration frequency detected in the step S18.
It has a step S31 of subtracting a predetermined value (for example, 30 Hz) by the PU 43. Then, the torsional vibration frequency after the subtraction in step S31 is calculated in step S2.
At 0, it is output to the second oscillator 45b.

The value thus subtracted may be stored in the memory unit 44 in advance, or the CP
You may make it calculate suitably in the program which shows the process sequence of U43.

In the two-dimensional laser radar of the second embodiment, the vibration of the mirror section 20 is based on the frequency value obtained by subtracting a predetermined value from the detection value of the vibration frequency in the mirror section 20 as described above. It is configured to perform control. As a result, even when vibration having a frequency higher than the natural vibration frequency in the bending direction and the twisting direction of the mirror portion 20 is applied as the disturbance, the influence of the disturbance vibration is suppressed and the stable resonance operation is maintained. can do. Therefore, particularly when mounted on a vehicle for use, it is possible to reduce the influence of vibration of the vehicle and sufficiently prevent the operation of the device from stopping.

The specific examples (3 Hz and 30 Hz) of the subtraction values given in the above description are the optimum values experimentally obtained by the present inventor on the basis of vibration or the like generated in the mounted vehicle. That is, the value to be subtracted may be set appropriately in advance.

Further, step S30 and step S31
The subtraction process in does not have to be always performed,
For example, the first and second signal conditioners 41
The output signals from a and 41b may be monitored by the CPU 43, and may be performed only when the output signal falls below a predetermined value. Alternatively, for example, after the resonance operation of the mirror section 20 is stopped due to excessive disturbance vibration, the resonance operation may be restarted.

(Third Embodiment) Next, as a third embodiment, the same vibration control as described above is performed in the mirror portion 20 only in the twisting direction, and in the bending direction, a relatively simple feedback is performed by a self-excited oscillator. A two-dimensional laser radar device configured to perform control will be described with reference to FIGS. 8 and 9. The two-dimensional laser radar device according to the third embodiment differs from the two-dimensional laser radar device according to the first embodiment described above only in the vibration control in the bending direction. The same parts as those in 1 are denoted by the same reference numerals in the drawings, and detailed description thereof will be omitted.

In this two-dimensional laser radar device, as shown in FIG. 8, in the drive control circuit 23, the output signal from the first signal conditioner 41a is the self-excited oscillator 5.
0, and the first oscillator 45a and the first interrupter 46b are omitted. In this two-dimensional laser radar device, relatively simple feedback control is performed by the self-excited oscillator 50 with respect to the vibration of the mirror section 20 in the bending direction, and the mirror is processed according to the processing procedure in the drive control circuit 23 shown in FIG. Only about the vibration of the part 20 in the torsion direction
Vibration control is performed based on the frequency detected by the piezoresistive element 21a.

In the two-dimensional laser radar device configured as described above, it is possible to perform tuning control based on the detected vibration frequency with respect to torsional vibration that is significantly affected by the hard spring effect and magnetic hysteresis. In addition, feedback control by the inexpensive self-excited oscillator 50 can be performed for bending vibration that is relatively less affected by the hard spring effect and magnetic hysteresis.
Therefore, it is possible to reduce the scale of the circuit mounted on the device, reduce the size and weight of the device, simplify the device configuration, and realize further cost reduction.

In this two-dimensional laser radar device, for example, the first frequency detector 42a and the input / output terminals ch1, ch5, ch3 in the CPU 43 can be further omitted, which further lowers the frequency. It is possible to achieve cost reduction, size reduction, and weight reduction.

Further, in this two-dimensional laser radar device, as shown in FIG. 10, in the same manner as in the second embodiment, before the step S20, the CPU 43 determines a predetermined value from the torsional vibration frequency detected in the step S18. It is also possible to have a step S31 of subtracting the value of (for example, 30 Hz), and to output the torsional vibration frequency after being subtracted in this step S31 to the second oscillator 45b in a step S20. As a result, when vibration control in the twisting direction is performed on the mirror section 20, it is possible to suppress the influence of disturbance vibration and maintain stable resonance operation.

(Fourth Embodiment) Next, as a fourth embodiment, a two-dimensional laser radar in which the drive control circuit 23 is provided with a pulse generator for applying a pulse voltage to the magnetic field applying means 22. The device will be described with reference to FIGS. 11 and 12. The two-dimensional laser radar device according to the fourth embodiment is different from the above-described two-dimensional laser radar device according to the first embodiment only in that the drive control circuit 23 includes a pulse generator. The same parts as those in the first embodiment are designated by the same reference numerals in the drawings, and detailed description thereof will be omitted.

In this two-dimensional laser radar device, as shown in FIG.
As shown in FIG. 3, the drive control circuit 23 is provided with first and second pulse generators 60a and 60b which respectively output predetermined pulse voltages. These first and second
The pulse generators 60a and 60b are configured to receive the timing signals output from the output terminals ch7 and ch8 of the CPU 43, respectively. When the timing signals are input, a predetermined pulse voltage is applied to each of the first and second pulse signals. And to the second output amplifiers 47a and 47b.

Further, in this two-dimensional laser radar device,
For example, as shown in FIG. 12, immediately after the power is turned on and the operation is started, the drive control circuit 23 performs a series of pulse drive processing to stabilize the vibration drive of the mirror section 20, and then the first It is configured to perform the same processing as that of the above embodiment.

That is, in this two-dimensional laser radar device, when the power is turned on in step S40 shown in FIG. 12, the output terminal ch7 of the CPU 43 of the drive control circuit 23 outputs to the first pulse generator 60a in step S41. A request to apply the pulse voltage is output.

Next, in step S42, the first pulse generator 60a outputs a voltage value of about 5 times the initial amplitude value stored in advance in the memory section 44, for example, 5 m.
A rectangular wave pulse voltage having a pulse width of about sec is output to the first output amplifier 47a. Here, the voltage value of the pulse voltage is 5 times the initial amplitude value, and the pulse width is 5 ms.
The reason for setting ec is that since the resonance frequency in the bending direction of the mirror section 20 is 200 Hz, the pulse width is set to 5 msec, which corresponds to the length of one resonance cycle, and a pulse voltage of this pulse width As the voltage value for generating the deflection angle in the bending direction in the mirror section 20, five times the initial amplitude value was set.

The voltage values and pulse widths of the pulse voltages output from the first and second pulse generators 60a and 60b may be appropriately set according to the resonance characteristics of the mirror section 20 and the like. The vibration amplitude of the mirror section 20 at the time of step S42 is indicated by time T4 in FIG.

Next, in step S43, the CPU 4
3 determines whether or not a predetermined time (for example, 20 msec) has elapsed since the pulse voltage was output in step S42. As a result, if the time has passed, the next step S
The routine proceeds to 44, and when it has not elapsed, the determination of step S43 is repeated.

Next, in step S44, the bending natural vibration frequency of the mirror section 20 is detected by the first frequency detector 42a based on the output signal from the first piezoresistive element 21a. The mirror unit 20 at this point
The vibration amplitude of is shown at time T5 in FIG. Also,
The bending natural vibration frequency detected at this time is calculated by the CPU 43.
Is temporarily stored in the memory unit 44 by the.

Next, in step S45, the CPU 4
3 outputs a predetermined waveform signal to the first oscillator 45a via the output terminal ch3 based on the bending natural vibration frequency detected in step S44 and the initial amplitude value recorded in advance in the memory section 44.

Next, in step S46, the CPU 4
3 is the second pulse generator 6 from the output terminal ch8
A request to apply a pulse voltage to 0b is output.

Next, in step S47, the second pulse generator 60b outputs a voltage value of about 2 times the initial amplitude value stored in advance in the memory section 44 for 2 m.
A rectangular wave pulse voltage having a pulse width of about sec is output to the second output amplifier 47b. Here, the voltage value of the pulse voltage is twice the initial amplitude value, and the pulse width is 2 ms.
The reason for setting ec is that the resonance frequency of the mirror portion 20 in the twisting direction is 2 kHz, so the pulse width is set to 1 of the resonance period.
Considering the length of the cycle (0.5 msec) and the responsiveness of the circuit forming the second pulse generator 60b,
It was set to 2 msec. Further, as the voltage value for causing the mirror section 20 to generate the normal deflection angle in the twisting direction with the pulse voltage having this pulse width, twice the initial amplitude value is set. In addition,
The vibration amplitude of the mirror section 20 at the time of this step S47 is shown at time T4 for convenience in FIG.

Next, in step S48, the CPU 4
3 determines whether or not a predetermined time (for example, 10 msec) has elapsed since the pulse voltage was output in step S47. As a result, if the time has passed, the next step S
The process proceeds to 49, and when it has not elapsed, the determination of step S48 is repeated.

Next, in step S49, the torsional natural vibration frequency of the mirror section 20 is detected by the second frequency detector 42b based on the output signal from the second piezoresistive element 21b. The mirror unit 20 at this point
The vibration amplitude of is shown at time T5 in FIG. Also,
The torsional natural vibration frequency detected at this time is the CPU 43
Is temporarily stored in the memory unit 44 by the.

Next, in step S50, the CPU 4
3 outputs a predetermined waveform signal to the first oscillator 45a via the output terminal ch4 based on the torsional natural vibration frequency detected in step S49 and the initial amplitude value recorded in the memory unit 44 in advance.

As shown in FIG. 12, the processing after step S50 is the same as that of the above-described second embodiment, and therefore its explanation is omitted here.

In the two-dimensional laser radar device as described above, at least when the power is turned on, the magnetic field applying means 22
A pulse voltage is applied to the mirror unit 20, the vibration frequency of the mirror unit 20 is detected when a predetermined time has elapsed after the pulse voltage was applied, and vibration control for the mirror unit 20 is performed based on the detection result. Therefore, the resonance operation of the mirror section 20 can be reliably and stably performed when the power is turned on even in an extreme operating environment such as when the environmental temperature around the device is extremely high or extremely low. . Therefore, the reliability of the device can be sufficiently ensured even when it is mounted on a vehicle provided in a tropical region or a cold region, for example.

In this two-dimensional laser radar device, for example, steps S30 and S31 shown in FIG. 12 may be omitted. However, as described in the second embodiment, steps S30 and S
When the subtraction process is performed in 31, it is possible to suppress the influence of the disturbance vibration and maintain the resonance operation more stably.

(Fifth Embodiment) Next, as a fifth embodiment, the same vibration control as that described above is performed on the mirror section 20 only in the twisting direction, and in the bending direction, a relatively simple feedback is performed by a self-excited oscillator. A two-dimensional laser radar device configured to include a pulse generator that applies a pulse voltage to the magnetic field applying unit 22 while performing control will be described with reference to FIGS. 14 and 15. The two-dimensional laser radar device of the fifth embodiment corresponds to a case where the above-described third embodiment and fourth embodiment are combined,
The same parts as those in the third and fourth embodiments are designated by the same reference numerals in the drawings, and detailed description thereof will be omitted.

In this two-dimensional laser radar device, as shown in FIG.
As shown in FIG. 7, in the drive control circuit 23, the output signal from the first signal conditioner 41a is input to the self-excited oscillator 50, and the first oscillator 45a and the first interrupter 46b are omitted. . Then, in this two-dimensional laser radar device, relatively simple feedback control is performed by the self-excited oscillator 50 for the vibration of the mirror section 20 in the bending direction, and the mirror is processed according to the processing procedure in the drive control circuit 23 shown in FIG. Only for the vibration of the portion 20 in the torsional direction, vibration control is performed based on the frequency detected by the first piezoresistive element 21a. Further, in this two-dimensional laser radar device, the drive control circuit 23 outputs a predetermined pulse voltage to the second output amplifier 47b in response to a request output from the output terminal ch8 of the CPU 43. Is provided.

In this two-dimensional laser radar device, as shown in FIG. 15, when the power is turned on in step S40, the drive control circuit 23 performs a series of pulse drive processing in steps S46 to S50.
This is performed only in the twisting direction of the mirror section 20. Then, when this series of pulse drive processing is completed and the mirror section 20 starts stable vibration operation, as in the third embodiment, with respect to vibration in the bending direction of the mirror section 20,
A relatively simple feedback control is performed by the self-excited oscillator 50, and the first piezoresistive element 21 is used only for the vibration of the mirror section 20 in the twisting direction as in the processing procedure shown in FIG.
Vibration control is performed based on the frequency detected by a.

In the two-dimensional laser radar device as described above, the magnetic field applying means 22 is provided at least when the power is turned on.
A pulse voltage is applied to the mirror unit 20, the vibration frequency of the mirror unit 20 is detected when a predetermined time has elapsed after the pulse voltage was applied, and vibration control for the mirror unit 20 is performed based on the detection result. Therefore, the resonance operation of the mirror section 20 can be reliably and stably performed when the power is turned on even in an extreme operating environment such as when the environmental temperature around the device is extremely high or extremely low. . Therefore, the reliability of the device can be sufficiently ensured even when it is mounted on a vehicle provided in a tropical region or a cold region, for example.

Further, for torsional vibration, which is significantly affected by the hard spring effect and magnetic hysteresis, tuning control based on the detected vibration frequency can be performed, and the hard spring effect and magnetic hysteresis can be used. Feedback control by the inexpensive self-excited oscillator 50 can be performed with respect to bending vibration having a relatively small influence. Therefore, it is possible to reduce the scale of the circuit mounted on the device, reduce the size and weight of the device, simplify the device configuration, and realize further cost reduction.

Therefore, the two-dimensional laser radar device not only enables more stable and highly accurate scanning of laser light due to these synergistic effects, but also further reduces the cost of the entire device. , The reliability can be significantly improved.

[Brief description of drawings]

FIG. 1 is a block diagram schematically showing an overall configuration of a two-dimensional laser radar device according to a first embodiment.

FIG. 2 is a plan view schematically showing a scanner unit included in the two-dimensional laser radar device.

3A and 3B are diagrams showing a scanner unit included in the two-dimensional laser radar device, FIG. 3A is a plan view seen from a side where a mirror unit is formed, and FIG. 3B is a side view.

FIG. 4 is a circuit configuration diagram showing a drive control circuit included in the two-dimensional laser radar device.

FIG. 5 is a flowchart showing an example of processing in a drive control circuit included in the two-dimensional laser radar device.

FIG. 6 is a schematic diagram showing a relationship between a vibration amplitude of a mirror section controlled by the drive control circuit and an elapsed time.

FIG. 7 is a flowchart showing an example of processing in a drive control circuit included in the two-dimensional laser radar device according to the second embodiment.

FIG. 8 is a circuit configuration diagram showing a drive control circuit included in a two-dimensional laser radar device according to a third embodiment.

FIG. 9 is a flowchart showing an example of processing in a drive control circuit included in the two-dimensional laser radar device of the third embodiment.

FIG. 10 is a flowchart showing another example of processing in the drive control circuit included in the two-dimensional laser radar device of the third embodiment.

FIG. 11 is a circuit configuration diagram showing a drive control circuit included in the two-dimensional laser radar device of the fourth embodiment.

FIG. 12 is a flowchart showing an example of processing in a drive control circuit included in the two-dimensional laser radar device according to the fourth embodiment.

FIG. 13 is a schematic diagram showing a relationship between a vibration amplitude of a mirror unit controlled by a drive control circuit included in the two-dimensional laser radar device of the fourth embodiment and elapsed time.

FIG. 14 is a circuit configuration diagram showing a drive control circuit included in a two-dimensional laser radar device according to a fifth embodiment.

FIG. 15 is a flowchart showing an example of processing in a drive control circuit included in the two-dimensional laser radar device of the fifth embodiment.

FIG. 16 is a problem in the conventional optical scanner device,
It is a figure explaining the hard spring effect which arises in a reflective mirror, and is a schematic diagram which shows the relationship between the vibration frequency and vibration amplitude of a reflective mirror.

FIG. 17 is a problem in the conventional optical scanner device,
It is a figure explaining the hysteresis which arises in the magnetostrictive film for driving a reflective mirror, and is a mimetic diagram showing the relation between the vibration frequency and vibration amplitude of a reflection mirror.

[Explanation of symbols]

10 Laser diode 11 Laser diode drive circuit 12 Control circuit 13 Photo detector 14 Light receiving circuit 15 Scanner 16 reflective mirror 20 Mirror section 21 Piezoresistive element 22 Magnetic field applying means 23 Drive control circuit 30 slit part 31 frame part 32 cantilever 33 Electrode part 34 Outer frame 41 signal conditioner 42 Frequency detector 43 CPU 44 memory section 45 oscillator 46 Interrupter 47 output amplifier 48 adder 50 Self-excited oscillation circuit 60 pulse generator

Claims (14)

[Claims] 1. The object irradiated by a light source is reflected by a mirror portion supported in a cantilever shape via an elastically deformable member to irradiate the object, and the object is oscillated by vibrating the mirror portion. In an optical scanner device that scans the light irradiating to the device, a driving unit that deforms the elastic deformation member to vibrate the mirror unit, a drive control unit that intermittently operates the driving unit, and a deformation of the elastic deformation member. Deformation amount detection means for detecting the amount, frequency detection means for processing the signal output from the deformation amount detection means to detect the vibration frequency of the mirror section, and operation of the drive means by the drive control means. The resonance frequency of the mirror section is adjusted by adjusting the operating frequency of the driving unit based on the vibration frequency detected by the frequency detecting unit when stopped. Light scanner device, characterized in that it comprises a frequency tuning means for tuning to a predetermined value. 2. The frequency tuning means subtracts a predetermined value from the value of the vibration frequency detected by the frequency detecting means when the operation of the driving means is stopped by the drive control means, and subtracts the value. The optical scanner device according to claim 1, wherein the operating frequency of the drive means is adjusted based on the value of the frequency. 3. A pulse voltage applying means for applying a pulse voltage to said driving means at least when the power is turned on, wherein said frequency tuning means has passed a predetermined time after applying the pulse voltage to said driving means. The optical scanner device according to claim 1 or 2, wherein the operating frequency of the drive means is adjusted based on the vibration frequency detected by the frequency detection means at a later point in time. 4. The drive means includes a first drive section for deforming the elastically deformable member in a torsion direction and a second drive section for deforming the elastically deformable member in a bending direction, and the deformation amount detection means. The means includes a torsional deformation amount detection unit that detects an amount of torsional deformation of the elastically deformable member, and a bending deformation amount detection unit that detects an amount of bending deformation of the elastically deformable member, and the frequency detection unit includes the torsional deformation member. A torsion frequency detecting unit that processes a signal output from the amount detecting unit to detect a torsional vibration frequency; and a bending frequency detecting unit that processes a signal output from the bending deformation amount detecting unit to detect a bending vibration frequency. 2. The object according to claim 1, wherein the driving means deforms the elastically deformable member in a twisting direction and a bending direction, respectively, so that the light from the light source is two-dimensionally scanned with respect to the object. Light of Canner device. 5. The frequency tuning means operates the first drive section based on a torsional vibration frequency detected by the torsion frequency detection section when the drive control means stops the operation of the drive means. By adjusting the frequency, the torsional resonance frequency of the mirror section is tuned to a predetermined value, and the drive control means controls the operation of the first drive section based on the output from the frequency tuning means. With
Based on the signal generated by the self-excited oscillation circuit, the second
The optical scanner device according to claim 4, wherein the operation of the driving unit is controlled. 6. The frequency tuning means subtracts a predetermined value from the value of the torsional vibration frequency detected by the torsional frequency detecting section when the operation of the driving means is stopped by the drive control means, and subtracts the value. 6. The torsional resonance frequency of the mirror section is tuned to a predetermined value by adjusting the operating frequency of the first drive section on the basis of the value of the generated frequency. Optical scanner device. 7. A pulse voltage applying means for applying a pulse voltage to the first drive section at least when the power is turned on, the frequency tuning means applying the pulse voltage to the first drive section. 7. The operating frequency of the first drive section is adjusted based on the torsional vibration frequency detected by the torsional frequency detection section after a predetermined time has elapsed after the operation. The optical scanner device according to. 8. The object irradiated by a light source is reflected by a mirror portion supported in a cantilever shape via an elastically deforming member to irradiate the object, and the object is vibrated to oscillate the object. In a method of driving an optical scanner device that scans light to be radiated onto a mirror, an intermittent mirror drive step of vibrating the mirror section by intermittently deforming and driving the elastically deformable member, A vibration frequency detection step of detecting a vibration frequency of the mirror section, and a resonance frequency of the mirror section by adjusting an operating frequency of the mirror section based on the vibration frequency detected when the driving of the mirror section is stopped. A frequency tuning step of tuning the frequency to a predetermined value. 9. In the frequency tuning step, a predetermined value is subtracted from a vibration frequency value detected when driving of the mirror section is stopped, and the operation of the mirror section is performed based on the subtracted frequency value. 9. The method of driving an optical scanner device according to claim 8, wherein the frequency is adjusted. 10. The operating frequency of the mirror section is pulse-driven at least when the power is turned on, and the operating frequency of the mirror section is determined based on a vibration frequency detected at a time point after a predetermined time has elapsed since the mirror section was pulse-driven. 10. The method of driving an optical scanner according to claim 8, further comprising a pulse driving step of adjusting. 11. In the intermittent driving step of the mirror section, the elastically deformable member is deformed in each of a twisting direction and a bending direction so that light from a light source is two-dimensionally scanned with respect to the object, and the vibration frequency is obtained. 9. The method for driving an optical scanner device according to claim 8, wherein in the detecting step, the torsional vibration frequency and the bending vibrational frequency are respectively detected based on the torsional deformation amount and the bending deformation amount of the elastically deformable member. . 12. In the frequency tuning step, based on the torsional vibration frequency detected in the vibration frequency detecting step when the driving of the mirror section is stopped,
By adjusting the operating frequency of the mirror section in the twisting direction, the torsional resonance frequency of the mirror section is tuned to a predetermined value, and the bending direction of the mirror section is adjusted based on the signal generated by the self-excited oscillation circuit. 12. The method for driving an optical scanner according to claim 11, wherein the operating frequency is controlled. 13. In the frequency tuning step, a predetermined value is subtracted from the torsional vibration frequency detected in the vibration frequency detecting step when the driving of the mirror section is stopped, and the frequency is subtracted based on the subtracted frequency value. 13. The method for driving an optical scanner device according to claim 11, wherein the torsional resonance frequency of the mirror portion is tuned to a predetermined value. 14. The mirror unit is pulse-driven in a twisting direction at least when the power is turned on, and the mirror unit is based on a torsional vibration frequency detected after a predetermined time has elapsed after the mirror unit was pulse-driven. 14. The method of driving an optical scanner according to claim 11, further comprising a pulse driving step of adjusting the operating frequency in the twisting direction.