JP2000105277A - Vehicle-to-vehicle distance holding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle-to-vehicle distance holding device capable of holding the vehicle-vehicle distance by scanning in a wide range even in a road with many curves or gradient during high speed traveling. SOLUTION: The optical axis is scanned to oscillate in the X-axis direction and in the Y-axis direction of the next car ahead by a galvanomirror 25, to scan in a wide range. CCDs (solid state image pickup device) 27, 28 detect a light signal corresponding to the vehicle-to-vehicle distance reflected by the galvanomirror 25 to heighen the detection accuracy. A phase comparing part 32 compares the phases of an incident signal of the light signal detected by the CCDs 27, 28 and a reflection signal to more quicken response. A distance calculating part 33 calculates the vehicle-to-vehicle distance according to the comparison results of the phase comparing part 32 to quickly calculate the accurate the vehicle-to-vehicle distance. CPU 31 gives a rumbling command when the vehicle-to-vehicle distance is not held according to the time infomration on the X-axis scanning of the galvanometer 25 and the time information on the Y-axis scanning thereof and the inter-vehicle distance information calculated by the distance calculating part 33, thereby informing a driver that the inter-vehicle distance between the next car ahead and the following vehicle is not held.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inter-vehicle distance maintaining device, and more particularly to an inter-vehicle distance maintaining device having a galvanomirror in an inter-vehicle distance detecting device.

[0002]

2. Description of the Related Art Conventionally, an inter-vehicle distance maintaining device has a time interval between the time when a laser beam emitted from a succeeding traveling vehicle is applied to the preceding traveling vehicle and the light reflected by the traveling vehicle returns to the succeeding traveling vehicle. There is one that detects the distance between vehicles by detecting the distance.

[0003] An example of the configuration of such an inter-vehicle distance holding device will be described below. FIG. 6 is a block diagram of a conventional inter-vehicle distance maintaining apparatus. Some laser units 100 include a light emitting unit 101 and a light receiving unit 102. The light emitting unit 101 includes a laser diode driving circuit 103, a laser diode 104, and a light emitting lens 105, and emits laser light in a pulsed manner at regular intervals. The light receiving unit 101
A light receiving lens 106 for receiving a laser beam reflected by a reflector of a preceding traveling vehicle, a photodiode 10
7, an amplifier 108, a signal processor 109 and the like. The inter-vehicle distance is calculated by the distance detection circuit 110 based on the time difference between the light emission by the light-emitting unit 101 and the light reception by the light-receiving unit 102, and an alarm is issued so that the inter-vehicle distance between the succeeding traveling vehicle and the preceding traveling vehicle can be kept constant. Is notified by the device 111. As a result, the inter-vehicle distance can be maintained within a certain range.

[0004] An example of this type of inter-vehicle distance holding device is disclosed in Japanese Patent Application Laid-Open No. Hei 4-232130, entitled "Inter-vehicle distance detection / warning device". Cancel the auto cruise when the occurrence of. For this purpose, the incident light of the laser output emitted from the following traveling vehicle is reflected from the preceding traveling vehicle when scanning the reflector of the rear bumper of the preceding traveling vehicle and returns to the following traveling vehicle. Then, the inter-vehicle distance is determined by detecting the time corresponding to the output light, and an alarm is issued when the inter-vehicle distance becomes smaller than the safe inter-vehicle distance determined based on the braking distance and idle running distance of the following traveling vehicle.

[0005]

However, the conventional inter-vehicle distance maintaining device uses a laser beam emitted from a laser diode 104 emitted by a subsequent traveling vehicle to scan the laser beam from the preceding traveling vehicle. Depending on the traveling speed and the traveling road conditions, there is a range in which the preceding traveling vehicle cannot be scanned, and there is a problem that a stable inter-vehicle distance cannot be maintained. Such a problem is particularly remarkable when traveling on a highway, traveling on a winding road or a road with many gradients, and cannot maintain a stable inter-vehicle distance. It can also cause rear-end collisions.

An object of the present invention is to scan a preceding traveling vehicle over a wide range two-dimensionally from a following traveling vehicle even on a high-speed traveling road, a winding road, or a road with many gradients, based on the result of this scanning. An object of the present invention is to provide an inter-vehicle distance holding device that stably holds an inter-vehicle distance by performing arithmetic processing.

[0007]

According to a first aspect of the present invention, a light emitted from a light source is scanned while being applied to a preceding traveling vehicle by changing a rotation angle, and reflected by the traveling vehicle. An inter-vehicle distance maintaining device for maintaining an inter-vehicle distance between a preceding traveling vehicle and a succeeding traveling vehicle based on the arrival time of the light, wherein scanning means for scanning the optical axis of the traveling vehicle in a two-dimensional direction; A light detecting means for detecting a light signal corresponding to the inter-vehicle distance reflected by a preceding traveling vehicle near the scanning means and outputting a two-dimensional light signal; and incidence of the light signal detected by the light detecting means. Phase comparing means for comparing the phases of the signal and the reflected signal, inter-vehicle distance generating means for generating an inter-vehicle distance based on the comparison result of the phase comparing means, and scanning in two-dimensional directions based on the output of the scanning means. Time Characterized by comprising a multi-address, and control means for ringing command based on the calculated inter-vehicle distance information by the distance calculation means.

[0008] The preceding traveling vehicle is scanned over a wide area while applying light emitted to the vehicle body of the preceding traveling vehicle from the light source on the following traveling vehicle side. When scanning the preceding traveling vehicle,
The inter-vehicle distance between the preceding traveling vehicle and the following traveling vehicle is maintained based on the time at which the reflected light arrives at the following traveling vehicle.

The scanning means of the inter-vehicle distance maintaining device scans the traveling vehicle two-dimensionally by swinging the optical axis of the traveling vehicle in the two-dimensional direction, thereby making it possible to scan the traveling vehicle over a wide range. In addition to this, the light detecting means detects an optical signal corresponding to the inter-vehicle distance reflected by the scanning means and outputs a two-dimensional optical signal, thereby performing a wide range of scanning, thereby increasing detection accuracy. can do. Further, the phase comparing means makes the response faster over a wide range by comparing the phases of the incident signal and the reflected signal of the optical signal detected by the light detecting means. The inter-vehicle distance generating means generates an accurate inter-vehicle distance quickly by generating the inter-vehicle distance based on the comparison result of the phase comparing means. The control means issues a sounding command when the inter-vehicle distance is not held based on the time information obtained by scanning in the two-dimensional direction based on the output of the scanning means and the inter-vehicle distance information generated by the inter-vehicle distance generation means. This informs the driver that the inter-vehicle distance between the preceding traveling vehicle and the following traveling vehicle is not sufficiently maintained.

According to a second aspect of the present invention, the light detecting means is a two-dimensional area sensor which photoelectrically converts the detected optical signals in the two directions of the X-axis and the Y-axis and outputs the signals as electric signals.

The light detecting means is a two-dimensional area sensor, and photoelectrically converts the detected optical signals in the two directions of the X-axis and the Y-axis and outputs them as electric signals, thereby improving detection accuracy over a wide range. can do.

In the third aspect, the phase comparing means sets the phases of the incident signal and the reflected signal corresponding to the incident light and the reflected light of the optical signal detected by the light detecting means, respectively, with reference to the frequency-divided signal of the reference frequency. It is characterized by comparing.

The phase comparing means compares the phases of the incident signal and the reflected signal corresponding to the incident light and the reflected light of the optical signal detected by the light detecting means with reference to the frequency-divided signal of the reference frequency, respectively. Phase comparison can be performed in a short time over a wide range.

According to a fourth aspect of the present invention, the distance generating means generates an inter-vehicle distance corresponding to the vehicle speed based on the comparison result of the phase comparing means, the phase information and the inter-vehicle distance information stored in the storage means. I do.

The inter-vehicle distance generating means calculates the inter-vehicle distance in accordance with the vehicle speed based on the comparison result of the phase comparing means and the phase information and the inter-vehicle distance information stored in the storage means, so that the inter-vehicle distance can be accurately calculated in a short time. The inter-vehicle distance between the following traveling vehicle and the preceding traveling vehicle can be obtained by calculation.

According to a fifth aspect of the present invention, the control means determines the distance between the vehicles based on the time information obtained by scanning in the X-axis and Y-axis directions based on the output of the scanning means and the distance between the vehicles calculated by the distance calculating means. A sounding command is output when the sound is not held.

The control means holds the inter-vehicle distance based on the time information of the scanning means scanning in the X-axis direction and the time information obtained by scanning in the Y-axis direction, and the inter-vehicle distance information calculated by the distance calculation means. By outputting the ringing command when the sound is not output, the driver can be notified accurately and quickly.

According to the present invention, the scanning means has a silicon substrate, and an outer movable plate formed in a frame shape on the silicon substrate;
A flat movable plate comprising an inner movable plate axially supported inside the outer movable plate is provided, and the upper surface of the outer movable plate is provided with a pair of first torsion bars on a pair of outer electrode terminals formed on the upper surface of the silicon substrate. A first planar coil whose both ends are electrically connected to each other is provided, and the upper surface of the inner movable plate passes through the outer movable plate portion from the second torsion bar to a pair of inner electrode terminals formed on the silicon substrate. A second planar coil electrically connected to each other via the other side of the first torsion bar, and a driving current of the first planar coil is controlled to rotate the outer movable plate by one cycle. The driving current of the second planar coil is controlled, the inner movable plate is displaced by a fixed angle, and this operation is repeated periodically to swing the optical axis two-dimensionally.

The scanning means is provided with a flat movable plate comprising an outer movable plate formed in a frame shape on a silicon substrate and an inner movable plate pivotally supported inside the outer movable plate. Both ends are electrically connected to the first planar coil via a first torsion bar portion to a pair of outer electrode terminals formed on the upper surface of the silicon substrate. The upper surface of the inner movable plate of the silicon substrate is electrically connected to the pair of inner electrode terminals through the outer movable plate portion from the second torsion bar and to the second planar coil via the other side of the first torsion bar. Connect to Thereby, after controlling the drive current of the first planar coil and rotating the outer movable plate for one cycle, controlling the drive current of the second planar coil, the inner movable plate is displaced by a fixed angle, This operation can be repeated periodically to swing the optical axis two-dimensionally.

[0020]

Next, an inter-vehicle distance holding apparatus according to an embodiment of the present invention will be described.

FIG. 1 is a diagram showing an installation example of an inter-vehicle distance holding device according to the present invention.
1 on the front bumper 12 while the preceding vehicle 13
An example in which a reflector 15 is installed on the rear bumper 14 of FIG. The installation position of the inter-vehicle distance holding device 20 is not limited to the front bumper 12, and the installation position of the reflector 15 is not limited to the rear bumper 14.

FIG. 2 is a diagram for explaining the main configuration of the present invention. In the description of FIG. 2, reference is made to the reference numerals used in the configuration of FIG.

The inter-vehicle distance maintaining device 20 includes a galvanomirror 25 (a specific structure of the galvanomirror 25 will be described later) as a means for emitting light in the X and Y axis directions to scan the preceding vehicle, a lens 26, and a two-dimensional mirror. CCD as an area sensor
(Solid-state imaging devices) 27 and 28, a semiconductor laser 29 as a light source, a driver 30 for driving a galvanometer mirror, a CPU 31 as a control center, a phase comparison unit 32 for comparing phases of detection signals of the CCDs 27 and 28, an inter-vehicle distance generating means Calculation unit 33, storage unit 34, and pulse generation circuit 35
Mainly composed of The inter-vehicle distance holding device 20 can be configured with a small installation space because each element can be configured compactly.

The overall operation of the following distance keeping apparatus 20 is as follows.
This is based on a command from the CPU 31. The CPU 31 issues a light emission instruction to the semiconductor laser 29 and a rotation instruction via the driver 30 to the galvanometer mirror 24, and also issues a switching control instruction such as a mode switching switch (not shown). CP
U31 operates based on the scanning angle signal, the light emission timing signal, and the measurement time signal. When the CPU 31 issues a light emission command to the pulse generation circuit 35, the pulse generation circuit 35 starts generating a series of light emission pulses having a fixed period.
The emission pulse output from the pulse generation circuit 35 is input to the semiconductor laser 29. The period of the light emission pulse is longer than the time required for light to reciprocate the maximum measurable distance.

When the CPU 31 issues a galvanometer mirror rotation command to the driver 30, the driver 30 causes the driver 30 to move the projection light scanning mirror to a predetermined angle range, for example, 2 degrees.
The galvanomirror 25 is rotated so as to be able to reciprocate in the horizontal direction within 00 mrad. The rotation speed of the galvanometer mirror 25 is
This is such that a plurality of, for example, 20 to 30 projection lights are projected within one scanning angle range.

The semiconductor laser 29 is pulse-driven by a drive circuit in response to a light-emitting signal, and emits a collimated laser beam having a vertically long cross section extending in the vertical direction, for example, about 15 mrad in the vertical direction. .

Although the details of the structure of the galvanometer mirror 25 will be described later, a first and a second torsion bar are provided to make the torsion bars orthogonal to each other so as to be able to swing in two dimensions.

The phase comparator 26 converts the phases of the incident wave signal and the reflected wave signal corresponding to the incident wave and the reflected wave of the laser light detected by the CCDs (solid-state imaging devices) 27 and 28 into the divided signals of the reference frequency. Compare with each other.

The distance calculation section 33 calculates an inter-vehicle distance based on the comparison result of the phase comparison section 32. The inter-vehicle distance is calculated on the basis of the inter-vehicle distance information and the phase information stored in advance in a memory (not shown).

The CPU 31 scans the galvanometer mirror 25 in the X-axis direction, calculates time information in the X-axis direction and the Y-axis direction corresponding to the arrival time of the light reflected by the reflector 15 of the preceding vehicle 13, and calculates the distance. When the inter-vehicle distance is not held based on the inter-vehicle distance information calculated by the unit 33, the CP
A sound command is issued from the U31 to the alarm 36 to notify the driving vehicle that the inter-vehicle distance is not sufficient.

FIG. 3 is an exploded perspective view of the galvanomirror employed in the present invention. The galvanomirror 25 is formed by bonding upper and lower glass substrates 41 and 42 as upper and lower insulating substrates made of borosilicate glass or the like on the upper and lower surfaces of a silicon substrate 40 as a semiconductor substrate as shown by arrows, respectively. The upper and lower glass substrates 41 and 42 have a three-layer structure, and have a structure in which square concave portions 41A and 42A formed by, for example, ultrasonic processing are provided at the central portions, respectively. When bonding to the silicon substrate 40, the upper glass substrate 41 is bonded to the silicon substrate 40 with the concave portion 41 </ b> A facing down. The lower glass substrate 42 is joined so that the concave portion 42A is located on the lower side of the silicon substrate 42. Thereby, a swing space of the movable plate 43 on which the reflection mirror 46 is provided is ensured, and the movable plate 43 is sealed.

The silicon substrate 40 is provided with a flat movable plate 43 composed of an outer movable plate 43a formed in a frame shape and an inner movable plate 43b pivotally supported inside the outer movable plate 43A. The outer movable plate 43a includes a first torsion bar 44
a, 44a to support the silicon substrate 40. The inner movable plate 43b includes first torsion bars 44a, 44a.
Torsion bars 44b, 44 whose axial direction is orthogonal to
b supports the inside of the outer movable plate 43a. Movable plate 43
a, 43b and the first and second torsion bars 44a,
44b is formed integrally with the silicon substrate 40 by anisotropic etching and is made of the same material as the silicon substrate 40.

The upper surface of the outer movable plate 43a is connected to a pair of outer electrode terminals 47a, 47b formed on the upper surface of the silicon substrate 40.
A planar coil 45a whose both ends are electrically connected to each other via a portion of one first torsion bar 44a is provided by being covered with an insulating layer. The upper surface of the inner movable plate 43B is connected to a pair of inner electrode terminals 47b, 4 formed on the silicon substrate 40.
7b, the first torsion bar 44A passes from the second torsion bar 44b through the outer movable plate 43a.
The planar coils 45b electrically connected to each other via the other side of the first coil are provided by being covered with an insulating layer.

The upper and lower glass substrates 41, 42
Eight disk-shaped permanent magnets 48a to 51a and 48b to 51b are arranged in pairs. The permanent magnets 48a and 48b of the upper glass substrate 41 facing each other.
The magnetic field acts on the planar coil 45a of the outer movable plate 43a with the permanent magnets 49a and 49b of the lower glass substrate 42 to rotate the outer movable plate 43a by interaction with a drive current flowing through the planar coil 45a. It is for.

The permanent magnets 50a and 50b of the upper glass substrate 41 facing each other are combined with the permanent magnets 51b and 51b of the lower glass substrate 44 by the flat coil 4 of the inner movable plate 43b.
This is for rotating the inner movable plate 43b by interaction with a drive current flowing through the planar coil 45b by applying a magnetic field to 5b. Permanent magnets 48 facing each other
When the upper surfaces of the a and 49a are S-poles, the upper surfaces of the permanent magnets 49a are provided so as to be N-poles, and the magnetic flux is arranged so as to cross in parallel with the plane coils 45a and 45b of the movable plate 43. Other facing permanent magnets 49a,
49b, permanent magnets 50a, 50b, permanent magnets 51a, 5
1b is also the same.

The lower surface of the lower glass substrate 42 is patterned and provided with detection coils 51a and 51b and detection coils 52a and 52b which are arranged to be electromagnetically coupled to the planar coils 45a and 45b, respectively. Detection coils 51a, 51b
Are provided symmetrically with respect to the first torsion bar 44a, and form a pair. Detection coils 52a, 52
b are provided at symmetrical positions with respect to the second torsion bar 44b and form a pair.

The pair of detection coils 51a and 51b detect the displacement angle of the outer movable plate 43a.
Mutual inductance between the planar coil 45a and the detection coils 52a and 52b based on the detection current flowing by superimposing the drive current on 5a changes due to the angular displacement of the outer movable plate 43a, and an electric signal corresponding to the angle change is generated. Output. The displacement angle of the outer movable plate 43a can be detected from the electric signal. The pair of detection coils 52a and 52b detect the displacement angle of the inner movable plate 43b in the same manner.

FIG. 4 is a plan view of the galvanomirror employed in the present invention. When a driving current is applied to the planar coil 45a of the outer movable plate 43a, the first torsion bars 44a, 44 will be described.
b, the outer movable plate 43a rotates in accordance with the current direction, and accordingly, the inner movable plate 43b also moves to the outer movable plate 43b.
It rotates integrally with a. Planar coil 4 of inner movable plate 43b
5b, the inner movable plate 4a is moved relative to the outer movable plate 43a in a direction perpendicular to the rotation direction of the outer movable plate 43a.
3b rotates about the second torsion bars 44b, 44b as a fulcrum. By controlling the drive current of the plane coil 45a,
After rotating the outer movable plate 43a for one cycle, the drive current of the planar coil 45b is controlled, and the inner movable plate 43b is displaced by a fixed angle. Can be swung two-dimensionally, and the preceding vehicle, which is the target vehicle, can be scanned two-dimensionally.

In the above embodiment, the galvanomirror 25-2
The inter-vehicle distance between the preceding vehicle 13 and the following vehicle 11 shown in FIG. 1 is reliably detected by the inter-vehicle distance holding device 20 by dimensional scanning, and an alarm can be sounded.

FIG. 5 is an operation diagram of the inter-vehicle distance maintaining device according to the present invention. In FIG. 5, the road 60 includes lanes L1 and L2.
, And the lane L1 is on the overtaking lane side. The preceding vehicles 13A and 13B preceding the following vehicle 11 are running, the preceding vehicle 13A runs on the lane L1, and the preceding vehicle 13B runs on the lane L2. In this case, the preceding vehicles 13A and 13B are scanned in the X and Y axis directions within the range of the angle A by the inter-vehicle distance maintaining device 20 of the following vehicle 11 running on the lane L1, and reflected by the reflectors 15A and 15B of the preceding vehicles 13A and 13B. The inter-vehicle distance is calculated from the time until the light returns to the inter-vehicle distance holding device 20 of the following vehicle 11. By the way, the conventional inter-vehicle distance holding device scans only the preceding vehicle 13A only in the range of the angle B.
The inter-vehicle distance to B cannot be measured, and the inter-vehicle distance may not be able to be ensured when driving at high speed or on a road with many turns.

The inter-vehicle distance holding device 20 of the above embodiment can reliably measure the inter-vehicle distance between the preceding vehicles 13A and 13B. Therefore, the inter-vehicle distance between not only the preceding vehicle 13A but also the preceding vehicle 13B can be held. Can be. As a result, the inter-vehicle distance from the succeeding vehicle 11 to the preceding vehicles 13A and 13B can be maintained over a wide range even when traveling on a highway, a winding road, or a road with many gradients, and the safe traveling distance can be maintained. Can be secured.

The above embodiment uses a CCD as the light detecting means.
Although 27 and 28 are used, the present invention is not limited to this. Any sensor may be used as long as it can detect light in the X-axis direction or the Y-axis direction. It may be provided in the axial direction.

In the above embodiment, the semiconductor laser 29 is used as the light source. However, the present invention is not limited to this.
A device using a laser diode or the like may be used.

In the above embodiment, the case where the inter-vehicle distance maintaining device is installed in the automobile has been described.
However, the present invention is not limited to this. For example, even when an inter-vehicle distance holding device is attached to a train, the inter-vehicle distance can be maintained by a similarly compact inter-vehicle distance holding device. By
Train accidents can be prevented beforehand. Thereby, a train accident at the time of overcrowded timetable can be prevented.

[0045]

According to the first aspect of the present invention, the emitted light is scanned while oscillating it against the preceding traveling vehicle while varying the rotation angle of the reflection mirror, and is based on the arrival time of the light reflected by the traveling vehicle. In order to maintain the inter-vehicle distance between the traveling vehicle and the own vehicle, the optical axis of the galvanomirror is two-dimensionally scanned and the preceding traveling vehicle is two-dimensionally scanned, and then an optical signal corresponding to the inter-vehicle distance is detected. Calculate an accurate inter-vehicle distance by comparing the phases of the incident signal and the reflected signal of the detected optical signal, and issue a sounding command when the inter-vehicle distance is not held based on the calculated inter-vehicle distance information, and It can indicate that the following distance is not sufficiently maintained, and can scan a wide area even when driving at high speeds, on winding roads, or on steep roads. It can be held from an inter-vehicle distance maintaining device apparatus.

According to the second aspect, in the light detecting means, 2
By using the dimensional area sensor to photoelectrically convert the detected optical signals in the two directions of the X-axis and the Y-axis and outputting them as electric signals, the detection accuracy can be improved over a wide range.

According to the third aspect, in the phase comparing means, the phases of the incident signal and the reflected signal respectively corresponding to the incident light and the reflected light of the optical signal detected by the light detecting means are based on the divided signal of the reference frequency. By comparing each
Phase comparison can be performed over a wide range in a short time.

According to the fourth aspect, the distance calculating means calculates the inter-vehicle distance according to the vehicle speed based on the comparison result of the phase comparing means and the phase information and the inter-vehicle distance information stored in the storage means. The distance between the following vehicle and the preceding vehicle can be accurately calculated in a short time.

According to the fifth aspect, the control means uses the time information for scanning the galvanomirror in the X-axis direction and the time information for scanning in the Y-axis direction, and the inter-vehicle distance based on the inter-vehicle distance information calculated by the distance calculation means. By outputting a sounding command when the vehicle is not held, the driver can be notified accurately and quickly, and a safe inter-vehicle distance can be maintained.

According to the sixth aspect, the driving current of the first planar coil is controlled to rotate the outer movable plate for one cycle, and then the driving current of the second planar coil is controlled. By repeating this operation periodically and shaking the optical axis two-dimensionally, a wide range of scans can be performed on high-speed running roads, even on roads with lots of meanders, and on roads with many gradients. Can be kept in range.

[Brief description of the drawings]

FIG. 1 is an installation example of an inter-vehicle distance holding device according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration of a main part of the embodiment.

FIG. 3 is an exploded perspective view of the galvanomirror of the embodiment.

FIG. 4 is a plan view of the galvanomirror of the embodiment.

FIG. 5 is an operation diagram of the embodiment of the present invention.

FIG. 6 is a block configuration example of a conventional inter-vehicle distance holding device.

[Explanation of symbols]

11: trailing vehicle, 12: front bumper, 13: preceding vehicle, 14: rear bumper, 15: reflector, 20: inter-vehicle distance holding device, 5: galvanometer mirror, 27, 28 ... C
CD, 29: semiconductor laser, 30: driver, 31: C
PU, 32: phase comparison unit, 33: distance calculation unit, 34: storage unit, 36: alarm device, 40: silicon substrate, 41, 42
... Lower glass substrate, 43 movable plate, 44 torsion bar, 45 planar coil.

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Claims (6)

[Claims] 1. A method according to claim 1, wherein the light emitted from the light source is scanned while being applied to a preceding traveling vehicle by changing a rotation angle, and based on a time at which light reflected by a vehicle body of the preceding traveling vehicle arrives. An inter-vehicle distance holding device that maintains an inter-vehicle distance between a traveling vehicle and a succeeding traveling vehicle, a scanning unit that scans the preceding traveling vehicle by swinging an optical axis in a two-dimensional direction, and a vicinity of the scanning unit. A light detecting means for detecting an optical signal corresponding to the time of arrival of light and outputting inter-vehicle distance information from the two-dimensional optical signal; an inter-vehicle distance corresponding to the phase of the incident signal and the reflected signal of the detected optical signal Phase comparison means for comparing information, inter-vehicle distance generation means for generating inter-vehicle distance information based on the comparison result of the phase comparison means, arrival of light reflected and scanned in the two-dimensional direction by the scanning means And time information of Rusorezore, the inter-vehicle distance control means for ringing command based on the generated inter-vehicle distance information generating means, the inter-vehicle distance retaining device characterized by comprising a. 2. The two-dimensional area sensor according to claim 1, wherein the light detecting means is a two-dimensional area sensor that photoelectrically converts the detected optical signals in the two directions of the X-axis and the Y-axis and outputs them as electric signals. The inter-vehicle distance holding device according to the above. 3. The phase comparing means compares the phases of the incident signal and the reflected signal respectively corresponding to the incident light and the reflected light of the optical signal detected by the light detecting means with reference to the frequency-divided signal of the reference frequency. The inter-vehicle distance maintaining device according to claim 1 or 2, wherein: 4. An inter-vehicle distance generating means for generating an inter-vehicle distance according to a vehicle speed based on a comparison result of the phase comparing means, phase information and inter-vehicle distance information stored in a storage means. The vehicle-to-vehicle distance maintaining device according to claim 1 or 3, wherein: 5. The inter-vehicle distance is determined based on time information for scanning in the X-axis direction and time information for scanning in the Y-axis direction of the scanning means, and inter-vehicle distance information generated by the inter-vehicle distance generation means. The inter-vehicle distance holding device according to claim 1 or 4, wherein a sounding command is output when the distance is not held. 6. The scanning means has a silicon substrate, and has a flat plate shape comprising an outer movable plate formed in a frame shape on the silicon substrate and an inner movable plate pivotally supported inside the outer movable plate. A movable plate is provided, and the upper surface of the outer movable plate is provided with a first planar coil having both ends electrically connected to a pair of outer electrode terminals formed on the upper surface of the silicon substrate via a first torsion bar. The upper surface of the inner movable plate is electrically connected to a pair of inner electrode terminals formed on the silicon substrate from the second torsion bar through the outer movable plate portion and through the other side of the first torsion bar. A second planar coil that is electrically connected, and controls a drive current of the first planar coil to control the drive current of the second planar coil after rotating the outer movable plate by one cycle. And the above And the movable plate by a predetermined angular displacement, the inter-vehicle distance retaining device according to claim 1, wherein the shake this operation in a two-dimensional periodically repeated optical axis.