JP3473737B2 - Vehicle speed measurement device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle speed measuring device for measuring the vehicle speed of a running vehicle.

[0002]

2. Description of the Related Art In a conventional vehicle speed measuring device, radio waves are emitted toward a vehicle traveling on a road, the frequency difference between the returning radio waves and the emitted radio waves is measured, and the Doppler effect for measuring speed is measured. What to use is known.

Further, in the conventional vehicle speed measuring device,
Multiple infrared rays are projected from an infrared type speed sensor installed on the road, the vehicle passing under it is detected by the reflected light of the infrared sensor, and the speed is determined by the time difference of the reflected light detection time between two points in the traveling direction. It is also known to measure.

FIG. 5 shows a conceptual diagram of an example of a conventional infrared sensor type vehicle speed measuring device. In FIG. 5, the speed measurement sensor 20 is composed of an infrared light emitting unit, a reflected infrared light receiving unit, a phase difference detecting unit, a computing unit and the like.

The speed measuring sensor 20 having the above-mentioned structure
Is an emission beam (R
a, Rb, Rc, Rd) and outputs the reflected beam (Ra
r, Rbr, Rcr, and Rdr) are respectively received by four independent reflection infrared ray receiving sections.

The velocity measuring sensor 20 constantly detects the phase difference between the emission beams (Ra, Rb, Rc, Rd) of each of these four systems and the reflected beams (Rar, Rbr, Rcr, Rdr) by the phase difference detection section. , The distance between the speed measurement sensor 20 and the reflection surface is calculated. The measurement vehicle 12 is a vehicle that measures speed.

When the measuring vehicle 12 does not exist in the vehicle speed measuring area, the emission beam is reflected on the road surface, and the phase difference from the reflected beam is always a constant value. Measuring vehicle 12
However, if the vehicle enters the vehicle speed measurement area and passes any one of the four emission beams, for example, the emission beam Ra
Is reflected by the measurement vehicle 12, and the phase difference between the emission beam Ra and the reflected beam Rar becomes small.

This phase difference is detected by the phase difference detecting section, the distance between the speed measuring sensor 20 and the reflecting surface of the measuring vehicle 12 is calculated by the calculating section, and the distance and the measuring vehicle 12 when the measuring vehicle 12 is not present. And the distance between the road surface and the reflecting surface of the road surface. When the distance of the reflecting surface is equal to or less than the set value, it is detected that the measurement vehicle 12 has entered the measurement area, and two points in the traveling direction, for example, the reflected beams Rar, R
If the time difference at the time of vehicle detection by cr or the reflected beams Rbr, Rdr is obtained, the emission beams Ra, Rb, R can be obtained in advance.
Since the distance between the radiating points c and Rd is known, the speed of the measuring vehicle 12 can be calculated by dividing the distance R between the radiating points at two locations in the traveling direction by the transit time difference Δt at two locations (R / Δt) by the calculation unit. Is required.

R represents the distance between the road surfaces of the emission beams Ra and Rc or the distance between the road surfaces of the emission beams Rb and Rd, and Δt represents the distance between the emission beams Ra and Rc of the measurement vehicle 12 or the emission beams Rb and Rd. Represents the time difference between passages.

In addition, considering that the width of one lane road is 3.3 m, this vehicle speed measurement area has 1.2
Measurement vehicle 1 by making a square measurement area of m
A speed of 2 is reliably detected in this area. Thus, the conventional infrared sensor type vehicle speed measuring device,
The vehicle speed of the passing measuring vehicle 12 can be measured by the time difference of the measuring vehicle 12 crossing the optical axes of the projected infrared rays at a plurality of points in the designated area.

[0011]

The conventional vehicle speed measuring apparatus using the Doppler effect speed measuring method has a problem that it is difficult to adjust it by installing an antenna for receiving the emitted radio waves.

Further, since the conventional vehicle speed measuring device using the infrared method for projecting a plurality of infrared rays detects the measuring vehicle 12 only at the four corners of the measurement area, the two wheels even when entering the measurement area. In the case of the measurement vehicle 12 such as a car that does not cross the infrared optical axis, there is a problem that the speed cannot be detected.

Further, since four sets of infrared type light emitting and receiving sensors are required, there is a problem that the device becomes large and complicated and the cost is high. Further, since infrared rays are emitted and the reflected light is always received, the installation place must be installed above the road surface, which poses a problem that installation work and maintenance are difficult.

The present invention has been made to solve the above problems, and an object thereof is to install a device easily and to measure a running vehicle speed with high accuracy. To provide.

[0015]

In order to solve the above problems, a vehicle speed measuring device according to the present invention comprises a light emitting means for generating a light beam, and a deflecting means for deflecting the light beam into a two-dimensional predetermined range. Light receiving means for receiving the reflected light of the light beam reflected from the two-dimensional predetermined range, control means for calculating the vehicle speed based on the reflected light received by the light receiving means, and information of this vehicle speed to the outside. And a display control means for displaying and outputting.

The vehicle speed measuring device according to the present invention comprises a light emitting means for generating a light beam, a deflecting means for deflecting the light beam into a two-dimensional predetermined range, and a light beam reflected from the two-dimensional predetermined range. Since the light receiving means for receiving the reflected light of, the control means for calculating the vehicle speed based on the reflected light received by the light receiving means, and the display control means for displaying and outputting the information of the vehicle speed to the outside, The light beam can be deflected in a two-dimensional predetermined range (detection area), and the speed of all passing vehicles such as two-wheeled vehicles and four-wheeled vehicles that pass through the detection area can be measured.

In the vehicle speed measuring device according to the present invention, the control means is provided with the deflection drive means for supplying the deflection means with a deflection drive signal in a two-dimensional predetermined range, and the light emitting means for emitting light at a constant cycle. And a phase difference detecting means for detecting a phase difference by receiving information from the light receiving means, and a speed is calculated based on a synchronization signal of a predetermined cycle and a signal from the phase difference detecting means. And a speed processing means.

Further, in the vehicle speed measuring device according to the present invention, the control means is provided with a deflection drive means for supplying the deflection means with a deflection drive signal in a two-dimensional predetermined range, and the light emitting means for emitting light at a constant cycle. And a phase difference detecting means for detecting a phase difference by receiving information from the light receiving means, and a speed is calculated based on a synchronization signal of a predetermined cycle and a signal from the phase difference detecting means. Since the speed measurement means is provided, the speed of the measurement vehicle can be measured with high accuracy with a simple configuration.

Further, the deflecting means according to the present invention is characterized in that it is a galvanometer mirror capable of periodically deflecting in a two-dimensional direction using a semiconductor manufacturing process.

Since the deflecting means according to the present invention is a galvano mirror capable of periodically deflecting in a two-dimensional direction by using a semiconductor manufacturing process, the light source is compactly constructed and the projection of light within a predetermined range is highly precise in two dimensions. Can be deflected.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings. The present invention can measure the speed of a running vehicle with high accuracy by a compact device by deflecting a light beam.

FIG. 1 is an installation image diagram of a vehicle speed measuring device according to the present invention. In FIG. 1, the vehicle speed measuring device 1 is installed on a pillar 101 provided in an L-shape from the side of the road above the road 102 such that the center part of the vehicle speed measuring device 1 is above the center of the road 102. To do.

The vehicle speed measuring device 1 is installed such that the light emitting part and the light receiving part are located on the road surface of the road 102, and the measurement range ABCD (two-dimensional range) of the light emission beam is the speed of all vehicles passing through this range. Can be measured.

When the measuring vehicle 12 enters the measuring range ABCD, the light beam projected from the vehicle speed measuring device 1 is
The phase difference between the reflected beam that is reflected by the measurement vehicle 12 and received by the vehicle speed measuring device 1 and the projected light beam is the phase difference between the projected light beam and the received reflected beam when the measurement vehicle 12 is not present. Is smaller than that of the measurement vehicle 12
Is detected.

The vehicle speed measuring device 1 measures the time difference between the time of passing the measuring range AB line and the time of passing the CD line, and the distance between AC or BD is known in advance. The speed of the measurement vehicle can be found by dividing by the time difference between the AB line and the CD line.

When the vehicle speed measuring device 1 measures the speed of the measuring vehicle 12, the vehicle speed measuring device 1 sends the transmission line 103
The speed data is transmitted to the display means 13 via the, and is stored in the display means 13, and the speed is displayed on a display provided on the display means 13 and a display device such as an LED.

Further, in FIG. 1, the vehicle speed measuring device 1 is installed at the center of the road 102 in the upward direction as an example, but it may be installed at an arbitrary position higher than the vehicle in the upright portion of the pillar 101.

FIG. 2 is a block diagram of the essential parts of the vehicle speed measuring device according to the present invention. In FIG. 2, the vehicle speed measuring device 1 includes a control unit 2, a light emitting unit 4, a light receiving unit 5, a deflecting unit 6, and a display control unit 7. The light emitting means 4
The deflecting means 6 constitutes the light emitting part of the device, and the light receiving means 5
Constitutes the light receiving part of the device.

The control means 2 is composed of various arithmetic means, processing means, memory, etc. based on a microprocessor, and generates a timing signal or various control signals based on a reference clock.

Further, the control means 2 drives the deflection means 6 by the deflection drive signal Vs so that the range of the angle of the laser beam to be irradiated within the measurement range can be set arbitrarily.

Further, the control means 2 takes in the reflection signal Lc of the reflected light Lr received by the light receiving means 5, and receives the reflection signal Lc.
The phase difference is calculated based on the above, and the measurement vehicle is detected. Further, the control means 2 supplies the speed information Vm to the display control means 7.

The light emitting means 4 is composed of, for example, a laser oscillation circuit, generates laser beam light corresponding to the light emission control signal Lk supplied from the control means 2, and projects the optical signal Ls to the deflecting means 6. As the laser beam light, for example, an infrared laser beam light having high convergence is used. The optical signal Ls is pulse-modulated so that which optical signal Ls corresponds can be determined by the reflected light Lr.

The light receiving means 5 is composed of a light receiving element such as a photodiode, receives the reflected light Lr of the optical signal Ls emitted in the measurement range ABCD, and receives the reflected signal Lc of the electric signal.
And is supplied to the control means 2.

The display control output means 7 is a buffer memory,
A display output signal Vo for displaying the speed of the measurement vehicle 12 is output to the external display means 13 based on the speed information Vm supplied from the control means 2, which is constituted by a modem or the like.

The deflecting means 6 is a galvano-mirror which is manufactured by a semiconductor process and can be easily deflected in a two-dimensional direction, and the galvano-mirror is two-dimensional in XY based on the deflection drive signal Vs supplied from the control means 2. Direction,
The light signal Ls emitted from the light emitting means 4 is deflected to detect the measurement vehicle 12 within the measurement range ABCD.
The deflecting means 6 reflects the reflected light Lr of the optical signal Ls emitted from the light emitting means 4 and inputs it to the light receiving means 5.

FIG. 3 is a block diagram of the essential parts of another embodiment of the vehicle speed measuring device according to the present invention. The same components as those shown in FIG. 2 are designated by the same reference numerals. In FIG. 3, the vehicle speed measuring device 1 includes a control unit 2, a light emitting unit 4, a light receiving unit 5, a display control unit 7, and a light emitting deflection unit 1.
4. The light receiving deflecting means 15 is provided.

Only parts different from the embodiment of FIG. 2 will be described with reference to FIG. 3. In FIG. 3, the light emission deflecting means 14 is a galvanometer mirror manufactured by a semiconductor process and capable of easily deflecting in a two-dimensional direction. An optical signal L emitted from the light emitting means 4 by displacing the galvano mirror in the two-dimensional XY direction based on the deflection drive signal Vs supplied from the means 2.
s is deflected to detect the measuring vehicle 12 within the measuring range ABCD.

The light receiving deflecting means 15 is the light emitting deflecting means 1.
As in the case of 4, a two-dimensional galvano mirror using a semiconductor process is used to reflect the reflected light Lr of the optical signal Ls emitted from the light emitting means 4 and input it to the light receiving means 5.

FIG. 3 shows the light emitting deflecting means 14 and the reflected light L.
Light receiving deflecting means 15 for reflecting r and inputting it to the light receiving means 5.
Are provided separately, and a common deflection drive signal V from the control means 2 is provided.
By s, the light emitting deflecting means 14 and the light receiving deflecting means 15 are deflected in synchronization with each other, and the reflected light Lr is input to the light receiving means 5. By performing the deflection separately, the response becomes faster and accurate vehicle speed measurement becomes possible.

As described above, the vehicle speed measuring means 1 according to the present invention includes the light emitting means 4 for generating a light beam and the deflecting means 6 (or the light emitting deflecting means 14) for deflecting the light beam into a predetermined two-dimensional range. ), The light receiving means 5 (or the light receiving deflecting means 15) for receiving the reflected light Lr of the optical signal Ls, and the reflected light Lr received by the light receiving means 5 (or the light receiving deflecting means 15), the vehicle speed is calculated. Since the control means 2 is provided, the vehicle speed of the measurement vehicle 12 passing through the measurement range can be measured from the optical signal Ls and the reflected light Lr.

FIG. 4 is a block diagram of the essential parts of the control means according to the present invention. In FIG. 4, the control unit 2 includes a speed processing unit 8, a deflection drive unit 9, a light emission control unit 10, and a phase difference detection unit 11. The speed processing means 8 is composed of a crystal oscillator, a frequency divider, a synchronizing signal generating means, various calculating means, a memory, etc., and performs synchronization control, speed calculation, and display control.

Further, the speed processing means 8 determines the scanning time,
In order to accurately measure the phase difference, a reference frequency is generated by a crystal oscillator, and a synchronization control signal Vt is generated based on a frequency obtained by dividing the reference frequency by a frequency divider, and the synchronization control signal Vt is deflected and driven. 9, the light emission control means 10 and the phase difference detection means 11 are supplied to perform synchronization control.

Further, the speed processing means 8 detects the measuring vehicle 12 entering and passing into the measurement range ABCD by the vehicle detection signal Vc inputted from the phase difference detecting means 11, and further detects the measurement range AB line and the CD line. From the time required to pass between the two points, the distance between the two points on the AB and CD lines is divided by the time difference between the points AB and CD to calculate the speed, and the display control means 7 is supplied with the speed information Vm. .

The deflection driving means 9 is composed of a signal generating means such as a sweep generator, and the reflection plate of the deflection means 6 is covered with the deflection driving signal Vs so as to cover the measurement range ABCD in FIG. Drives deflection in the axial direction. The deflection drive means 9 may be configured to drive the deflection means 6 intermittently so that the deflection of the deflection means 6 hits the measurement ranges A to E shown in FIG. Good.

The light emission control means 10 is composed of, for example, a pulse generation circuit, and in accordance with the synchronization control signal Vt from the speed processing means 8, causes the light emission means 4 to emit the laser beam light at a constant cycle. It is controlled by Lk.

The phase difference detecting means 11 is composed of an arithmetic circuit, a buffer memory and the like, and is based on the reflection signal Lc supplied from the light receiving means 5 and the synchronization control signal Vt supplied from the speed processing means 8. The measurement vehicle 12 is detected by detecting the phase difference, and the vehicle detection signal Vc is output to the speed processing means 8. The phase difference is always a constant value when there is no measurement vehicle 12, and it is determined that the measurement vehicle 12 has entered when the phase difference has continuously changed.

Thus, the control means 2 according to the present invention
Is a deflection drive means 9 for controlling the deflection means 6, a light emission control means 10 for controlling the light emission means 4, and a phase difference detection for detecting the measurement vehicle 12 by detecting a phase difference from the reflection signal Lc from the light receiving means 5. Since the means 11 and the speed at which the measuring vehicle 12 is detected are used to measure the time for passing the measuring range ABCD of FIG. 1 and to calculate the speed of the measuring vehicle 12, the speed is passed through the measuring range. The speed of the measurement vehicle 12 can be measured with high accuracy.

FIG. 5 is a block diagram of a galvanometer mirror used as the deflecting means according to the present invention. In FIG. 5, a galvano mirror 30 is a silicon substrate 32 which is a semiconductor substrate.
The upper and lower surfaces of the upper glass substrate 33 and the lower glass substrate 34, which are made of borosilicate glass or the like, are superposed in a sandwich shape from above and below and bonded to each other to form a three-layer structure.

The upper glass substrate 33 and the lower glass substrate 34 are provided with recesses 33A and 34A formed by ultrasonic processing, for example, in the central portions thereof, and the silicon substrate 32 is provided.
In the case of joining to, the concave portions 33A and 34A are arranged so as to be on the silicon substrate 32 side. With such an arrangement, a swinging space for the movable plate 35 on which the reflection mirror 38 is provided is formed, and a sealed structure is formed.

The silicon substrate 32 is provided with a flat plate-shaped movable plate 35 including an outer movable plate 35A formed in a frame shape and an inner movable plate 35B axially supported inside the outer movable plate 35A. The outer movable plate 35A includes the first torsion bar 3
The inner movable plate 35B is rotatably supported by the silicon substrate 32 by 6A and 36A, and the inner movable plate 35B includes the first torsion bars 36A and 36A.
A second torsion bar 36B, 3 whose axial direction is orthogonal to A
6B, it is pivotally supported inside the outer movable plate 35A. The outer movable plate 35A, the inner movable plate 35B, the first torsion bar 36A, and the second torsion bar 36B are integrally formed on the silicon substrate 32 by anisotropic etching, and are formed of the same material as the silicon substrate 32.

On the upper surface of the outer movable plate 35A, a pair of outer electrode terminals 39A, 39 formed on the upper surface of the silicon substrate 32.
A planar coil 37A, both ends of which are electrically connected to A through one portion of the first torsion bar 36A, is formed by being covered with an insulating layer. On the other hand, the inner movable plate 35
On the upper surface of B, the second torsion bar 3 is formed on the pair of inner electrode terminals 39B, 39B formed on the upper surface of the silicon substrate 32.
A planar coil 37B, which is electrically connected from 6B through the external movable plate 35A and via the other of the first torsion bars 36A, is formed by being covered with an insulating layer.

The plane coil 37A and the plane coil 37B are
It is formed by an electroformed coil method by electrolytic plating. The outer movable plate 35A and the inner electrode terminal 39B are connected to the silicon substrate 3
The flat coils 37A and 37B are simultaneously formed on the surface 2 by electroforming. A reflection mirror 38 is formed at the center of the inner movable plate 35B surrounded by the plane coil 37B.

Cylindrical permanent magnets 40A to 43A and 40B to 43B, each pair of two, are arranged on the upper glass substrate 33 and the lower glass substrate 34 as shown in the figure. Permanent magnets 40 facing the upper glass substrate 33
A, 41A and the permanent magnets 40B, 41B facing the lower glass substrate 34, the planar coil 3 on the outer movable plate 35A.
A magnetic field is applied to 7A, and the outer movable plate 35A is rotated by the interaction with the drive current flowing in the planar coil 37A.

On the other hand, the opposing permanent magnets 42A and 43A of the upper glass substrate 33 and the opposing permanent magnets 42B and 43B of the lower glass substrate 34 cause a magnetic field to act on the plane coil 37B on the inner movable plate 35B, thereby causing a flat surface. The inner movable plate 35B is rotated by the interaction with the drive current passed through the coil 37B.

The opposing permanent magnets 40A and 41A have opposite polarities in the upper and lower sides, for example, the upper surface of the permanent magnet 40A is S.
If it is a pole, the upper surface of the permanent magnet 41A is arranged so as to be an N pole, and further, the magnetic flux is arranged so as to cross the plane coil portion of the movable plate 35 in parallel. Other facing permanent magnets 42A and 43A, permanent magnets 40B and 41B, permanent magnet 4
The same applies to 2B and 43B.

Permanent magnets 40A and 40 facing each other in the vertical direction
The relationship with B is that the upper and lower polarities are the same, for example, the permanent magnet 40
If the upper surface of A is the S pole, the upper surface of the permanent magnet 40B is also arranged to be the S pole. Other permanent magnets 41A and 41B facing each other in the vertical direction, permanent magnets 42A and 42B, permanent magnet 4
3A and 43B are similarly arranged. Thereby, the movable plate 3
Forces act in opposite directions at both ends of 5.

On the lower surface of the lower glass substrate 34, the detection coils 45A and 45B and the detection coils 46A and 46, which are arranged to electromagnetically couple with the plane coils 37A and 37B, respectively.
B is formed in a pattern. Detection coils 45A, 45B
Are symmetrically arranged with respect to the first torsion bar 36A, and the detection coils 46A and 46B are symmetrically arranged with respect to the second torsion bar 36B.

The pair of detection coils 45A and 45B are for detecting the displacement angle of the outer movable plate 35A, and the flat coil 37A is generated on the basis of the detection current which is superposed on the drive current passed through the flat coil 37A. And detection coil 45
Mutual inductance with A and 45B is the outer movable plate 35A.
The displacement angle of the outer movable plate 35A can be detected from the change in the mutual inductance.

On the other hand, the pair of detection coils 46A and 46B can also detect the displacement angle of the inner movable plate 35B in the same manner. The displacement of the outer movable plate 35A corresponds to the displacement in the X-axis direction, and the displacement of the inner movable plate 35B corresponds to the displacement in the Y-axis direction, whereby the two-dimensional displacement of the reflection mirror 38 becomes possible. .

As described above, the deflection means 6 according to the present invention is
Since the galvanometer mirror 30 is capable of easily performing two-dimensional deflection using a semiconductor manufacturing process, it is possible to perform highly accurate two-dimensional deflection even in a small space on the road on which the vehicle travels.

In this embodiment, the vehicle speed measuring device 1 is integrated as shown in FIG.
The deflecting means 6 and the light receiving means 5 may be integrated and installed on the column 101 shown in FIG. Further, the light receiving means 5 may be arranged separately from the light emitting means 4 and the deflecting means 6.

[0062]

As described above, the vehicle speed measuring device according to the present invention includes a light emitting means for generating a light beam, a deflecting means for deflecting the light beam into a two-dimensional predetermined range, and
Light receiving means for receiving the reflected light of the light beam reflected from a predetermined range of dimensions, control means for calculating the vehicle speed based on the reflected light received by the light receiving means, and information of this vehicle speed is displayed outside Since the display control means for outputting is provided, the light beam can be deflected in a two-dimensional predetermined range (detection area), and the speed of all passing vehicles such as two-wheeled vehicles and four-wheeled vehicles that pass through the detection area can be detected. It is possible to measure and monitor the traffic situation of the vehicle such as vehicle speed violation and traffic jam.

In the vehicle speed measuring device according to the present invention, the control means is provided with the deflection drive means for supplying the deflection means with a deflection drive signal in a two-dimensional predetermined range, and the light emitting means for emitting light at a constant cycle. And a phase difference detecting means for detecting a phase difference by receiving information from the light receiving means, and a speed is calculated based on a synchronization signal of a predetermined cycle and a signal from the phase difference detecting means. Since the speed measurement means is provided, the speed of the measurement vehicle can be measured with high accuracy and the economy is excellent with a simple configuration.

Further, since the deflecting means according to the present invention is a galvanometer mirror capable of periodically deflecting in a two-dimensional direction using a semiconductor manufacturing process, it is possible to obtain a highly accurate two-dimensional image in a small space on a road on which a vehicle travels. Can be deflected.

Therefore, it is possible to provide a vehicle speed measuring device which is easy to install and can measure the speed of a running vehicle with high accuracy.

[Brief description of drawings]

FIG. 1 is an installation image diagram of a vehicle speed measuring device according to the present invention.

FIG. 2 is a block diagram of a main part of a vehicle speed measuring device according to the present invention.

FIG. 3 is a block diagram of the main part of another embodiment of the vehicle speed measuring device according to the present invention.

FIG. 4 is a block diagram of a main part of a control means according to the present invention.

FIG. 5 is a configuration diagram of a galvanometer mirror used as a deflection unit according to the present invention.

FIG. 6 is a conceptual diagram of an example of a conventional infrared sensor type vehicle speed measuring device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Vehicle speed measuring device, 2 ... Control means, 4 ... Light emitting means, 5 ... Light receiving means, 6 ... Deflection means, 7 ... Display control means,
8 ... Speed processing means, 9 ... Deflection drive means, 10 ... Emission control means, 11 ... Phase difference detection means, 12 ... Vehicle, 13 ... Display means, 14 ... Emission deflection means, 15 ... Light reception deflection means,
20 ... Speed measurement sensor, 30 ... Galvanometer mirror, 101
... Pillars, 102 ... Roads, 103 ... Transmission lines, Lc ... Reflected signals, Lk ... Emission control signals, Lr ... Reflected light, Ls ... Optical signals, Ra to Rd ... Emitted beams, Rar to Rdr ... Reflected beams, Vc ... Vehicles Detection signal, Vm ... Speed information, Vo ... Display output signal, Vr ... Speed measurement sensor, Vs ... Deflection drive signal, Vt ... Synchronous control signal.

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G01P 3/68 G01S 7/48 G01S 17/88 G08G 1/052

Claims (3)

(57) [Claims] 1. A vehicle speed measuring device for measuring the speed of a vehicle traveling on a road, comprising: a light emitting means for generating a light beam; a deflecting means for deflecting the light beam into a two-dimensional predetermined range; Light receiving means for receiving the reflected light of the light beam reflected from a predetermined range of dimensions, control means for calculating the vehicle speed based on the reflected light received by the light receiving means, and information of this vehicle speed is displayed outside A vehicle speed measuring device comprising: a display control unit for outputting. 2. The deflection means for supplying a deflection drive signal within a predetermined two-dimensional range to the deflection means, and a light emission control means for controlling the light emission means so as to emit light at a constant cycle. A phase difference detecting means for detecting a phase difference by receiving information from the light receiving means, and a speed processing means for calculating a speed based on a synchronization signal having a predetermined cycle and a signal from the phase difference detecting means. The vehicle speed measuring device according to claim 1, further comprising: 3. The vehicle speed measuring device according to claim 1, wherein the deflecting means is a galvanometer mirror capable of periodically deflecting in a two-dimensional direction using a semiconductor manufacturing process.