JP2002031685A - Reflection measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reflection measuring device capable of exactly self- diagnosing the functional state of a light emitting means and a light receiving means and attaining small-sizing and low cost. SOLUTION: By reflecting a laser beam from a light emitter with each reflection surface H of a rotating polygon mirror 30, the reflection light scanned in a specific angle range is emitted from an emission window 102 and is received with a photodetector 50 from an incidence window 104. A laser radar 2 measuring the distance to an object in this manner has a self-diagnosis light path in which a laser light is generated by the light emitter when each of reflection mirror surfaces H of the polygon mirror 30 faces to a specific direction, and the laser light from the reflection surface H is reflected from a transparent window plate 130 provided inside the two windows 102 and 104 and reaches the photodetector 50. Thus, the light emitter generates a laser light when each of the reflection surfaces H of the polygon mirror 30 faces to the specific direction. If the photodetector normally receives the reflection light and cannot convert to electric signal, then it is judged abnormal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of scanning a light beam, emitting the light beam, and receiving the reflected light.
The present invention relates to a reflection measurement device for detecting information such as the position and distance of an object existing in the light beam emission direction, and more particularly to a reflection measurement device having a self-diagnosis function of light emission and light reception.

[0002]

2. Description of the Related Art Conventionally, for example, in a vehicle, a system that detects an obstacle such as a preceding vehicle and issues an alarm or controls a vehicle speed so as to maintain a predetermined inter-vehicle distance with the preceding vehicle has a laser beam. And the like, scans and emits a light beam in a predetermined angle range around the vehicle, and receives a reflected wave (reflected light) of the emitted light beam, thereby detecting the position of an object existing in the emission direction of the light beam. A reflection measuring device that detects information such as a distance (distance to the object) or a relative speed (relative speed to the object) is used.

[0003] A typical example of this type of reflection measuring device is a scanning laser radar device that scans and emits a laser pulse (pulsed laser light). Here, the configuration of a conventional reflection measuring device will be described with reference to FIG. Here, the description will be made on the assumption that the reflection measuring device is a scanning laser radar device.

As shown in FIG. 7, a scanning laser radar device 200 has a front surface (see FIG.
Is provided with a window for transmitting the laser light, one of the windows serves as an emission window 202 for emitting the laser light, and the other window serves as the emission window 2.
An entrance window 203 into which the reflected light of the laser light emitted from the laser beam 02 is incident.

[0005] Inside the housing 201, foreign substances such as water and dust are contained in the exit window 202 and the entrance window 203.
In order to prevent intrusion into the interior of the device 01, a continuous window plate 204 capable of transmitting light is provided. Further, in the housing 201, a laser diode 205 as a pulse-driven light emitting element is provided behind the emission window 202 (below in FIG. 7).
A photodiode 206 serving as a light receiving element that receives the reflected light incident from the incident window 203 and converts the reflected light into an electric signal is provided at the back of the light receiving element 3. The laser diode 205 is mounted on a light emitting circuit board 207 together with a driving circuit for driving the laser diode to emit light, and the photodiode 206 amplifies an electric signal converted from light by the photodiode 206. It is mounted on a light receiving circuit board 208 together with an amplifying circuit and the like.

In such a laser radar device 200,
The laser pulse generated by the laser diode 205 is reflected on each reflecting surface of a well-known polygon mirror (not shown) rotated at a constant speed, for example, so that the laser pulse is scanned within a predetermined angle range and the emission window 202 is formed. From the housing 201
Out of the device. On the other hand, the reflected light of the laser light (emitted light) emitted from the emission window 202 enters the housing 201 from the incidence window 203, is collected by a light receiving lens (not shown), and is received by the photodiode 206.

[0007] This type of laser radar device 200
Then, from the emission timing of the laser light (that is, the timing at which the laser diode 205 is driven to generate the laser light), until the laser light hits an object existing outside the housing 201 and returns. Based on the time difference (that is, until the reflected light of the emitted laser light is received by the photodiode 206), the distance to the object or the like is detected, and the detection result is used as an electronic control device to which the device 200 is connected. Output to

On the other hand, this type of laser radar apparatus 200 has a function of self-diagnosing whether the light emitting operation of the laser diode 205 and the light receiving operation of the photodiode 206 are normally performed. As shown in FIG. 7, in this type of laser radar device 200, a laser beam generated by the laser diode 205 is used for self-diagnosis as to whether the light emitting operation of the laser diode 205 is normally performed. A light receiving element 209 for monitoring light emission is provided at a position where a part of the light leaks and reaches, and a control unit in the device 200 outputs an output indicating light reception to the light receiving element 209 at the drive timing of the laser diode 205. When it is detected that there is no light, the light emitting operation of the laser diode 205 (in other words,
5 and a driving circuit for driving the light-emitting device 5 for light emission) are determined to be abnormal.

Further, in order to perform a self-diagnosis as to whether or not the light receiving operation of the photodiode 206 is normally performed, a test laser beam is obliquely forward of the photodiode 206 and obliquely to the light receiving surface of the photodiode 206. Light-emitting element 210 for light reception monitoring for providing
The control unit in 00 causes the light emitting element 210 to emit light at an appropriate timing and monitors the output of the photodiode 206 at that time. In other words, if the output indicating light reception does not appear on the photodiode 206 in spite of causing the light-emitting element 210 for light reception monitoring to emit light, the control unit performs the light-receiving operation of the photodiode 206 (in other words, the photodiode 206 It is determined that an abnormality has occurred in the light receiving means including the amplifier and an amplifier circuit for processing the output.

[0010]

According to the conventional laser radar apparatus 200 described above, it is possible to detect an abnormality relating to the emission and reception of laser light by itself and to take appropriate measures, but the following problems arise. There is.

(A) First, a light-receiving element 20 for monitoring light emission
9 and an electronic circuit for amplifying the output of the light receiving element 209 and a light emitting element 210 for monitoring the light receiving and an electronic circuit for driving the light emitting element 210 must be additionally provided. Cost and size increase.

(B) Further, the light receiving element 20 for monitoring light emission
No. 9 must be arranged beside an original optical path for emitting laser light from the emission window 202 (hereinafter referred to as an emission optical path) so as not to hinder emission of laser light from the emission window 202. As described above, light leaks from the output optical path. For this reason, the accuracy of determining whether the laser diode 205 emits light normally cannot be increased.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and accurately self-diagnoses the operating state of a light emitting means for generating a light beam and a light receiving means for receiving reflected light of the light beam. It is an object of the present invention to provide a reflection measuring device capable of performing the measurement and reducing the size and cost of the device.

[0014]

Means for Solving the Problems and Effects of the Invention In order to achieve the above object, the reflection measuring apparatus of the present invention according to the first aspect of the present invention has a structure in which a front window is provided. A light emitting means, and a reflecting surface for reflecting the light beam generated by the light emitting means, and the direction of the reflecting surface with respect to the window is regularly changed, so that the light beam from the light emitting means is scanned. A light scanning means for emitting light from the window to the outside of the housing; and a light receiving means for receiving reflected light of a light beam emitted from the window by the light scanning means.

In the reflection measuring device, the light beam is scanned by the light emitting means and the light scanning means to the outside through the window of the housing and emitted, and the reflected light of the emitted light beam is received by the light receiving means. Thus, information on an object existing in the light beam emission direction is detected. As described above, the information on the object is the position of the object, the distance to the object, the relative speed to the object, and the like.

Here, in the reflection measuring apparatus of the present invention, the following optical path for self-diagnosis exists in the housing. That is, this self-diagnosis optical path is used to emit a light beam to the outside of the housing when the direction of the reflection surface of the light scanning means is regularly changed to scan the light beam from the light emitting means. In other words, when the light emitting means emits a light beam when the light is directed to a specific direction (not the direction corresponding to the scanning range for detecting the information), the light beam is reflected by the reflecting surface of the light scanning means. After that, the light path is reflected at a predetermined location in the housing and reaches the light receiving means.

Further, the reflection measuring device of the present invention is provided with a self-diagnosis unit, and the self-diagnosis unit sends a light beam to the light-emitting unit when the reflection surface of the optical scanning unit is in the specific direction. The operating state of the light emitting means and the light receiving means is diagnosed by monitoring whether or not a signal indicating that the reflected light of the light beam is received is output from the light receiving means.

That is, if both the light emitting means and the light receiving means are normal, when the light emitting means generates a light beam when the reflecting surface of the light scanning means is in the specific direction, the light beam is The light is received by the light receiving means via the optical path for self-diagnosis in the housing, and the light receiving means outputs a signal indicating that the reflected light of the light beam is received. On the other hand, if at least one of the light-emitting means and the light-receiving means is abnormal, the light-emitting means may generate a light beam when the reflecting surface of the optical scanning means is in the specific direction. Does not output a signal indicating that the reflected light of the light beam has been received.

Therefore, the self-diagnosis means generates a light beam in the light emitting means when the reflecting surface of the light scanning means is in the specific direction, and receives a signal indicating that the reflected light of the light beam has been received. If no signal is output from the means, it is determined that one of the light emitting means and the light receiving means is abnormal.

According to the reflection measuring apparatus of the first aspect, the light is emitted to the outside without providing the light emitting element 209 for light emission monitoring and the light emitting element 210 for light receiving monitoring as in the conventional apparatus 200 described above. The operating state of both the light emitting means for generating the light beam and the light receiving means for receiving the reflected light of the light beam emitted to the outside can be self-diagnosed. Cost reduction can be realized.

In addition, this reflection measuring device does not detect the leaked light from the output light path as in the conventional device 200, but generates the light generated by the light emitting means when diagnosing the operating state of the light emitting means and the light receiving means. Since the light beam reaches the light receiving unit almost directly via the self-diagnostic optical path in the housing, the accuracy of determining whether the light emitting unit is operating normally can be improved.

Therefore, according to the reflection measuring device of the first aspect, it is possible to accurately perform the self-diagnosis of the operating state of the light emitting means and the light receiving means, and to realize a reduction in size and cost of the apparatus. it can. Next, according to a second aspect of the present invention, there is provided the reflection measuring device according to the first aspect, wherein the window of the housing includes an emission window for emitting the light beam, and the light beam emitted from the emission window. Reflected light is incident, the light receiving means comprises an entrance window for receiving the reflected light,
Furthermore, inside the housing, its exit window and entrance window
A continuous window plate capable of transmitting light is provided.

In the reflection measuring apparatus according to the second aspect, the light beam generated by the light emitting means and reflected by the reflecting surface of the light scanning means is reflected by the window plate to receive the light in the specific direction. It is the direction to reach. That is,
In the reflection measuring device according to claim 2, a light-transmitting window plate for preventing foreign matter such as water or dust from entering the housing from the exit window and the entrance window is provided at the predetermined location in the housing (ie, The light beam generated by the light emitting means and reflected by the reflecting surface of the light scanning means is used as a part which is reflected in the housing and reaches the light receiving means.

Therefore, according to the reflection measuring apparatus of the second aspect, it is not necessary to separately provide a reflecting member for allowing the light beam from the light emitting means to reach the light receiving means in the housing, which is more effective.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A scanning laser radar device as a reflection measuring device according to an embodiment of the present invention will be described below with reference to the drawings. The scanning laser radar device described below is provided at the front of the vehicle so that the laser beam can be emitted in the traveling direction of the vehicle and the reflected light can be received. . Further, the left and right directions in the following description are directions viewed from the scanning laser radar device itself.

FIG. 1 is a perspective view showing components of a scanning laser radar device (hereinafter, simply referred to as a laser radar device) 2 of the present embodiment, and shows a state where the laser radar device 2 is disassembled into its components. , From the upper left side. FIG. 2 is a diagram showing the arrangement of components inside the laser radar device 2 from above, and FIG.
FIG. 2 is a diagram illustrating the arrangement of a reflection mirror 20, a polygon mirror 30, and the like from the right side.

As shown in FIGS. 1 to 3, the laser radar device 2 of the present embodiment has the following optical system. That is, the optical system of the laser radar device 2 includes a lens unit 10 that generates substantially parallel laser light, a reflection mirror 20 that reflects the laser light emitted from the lens unit 10 and guides the laser light in a predetermined direction, and a reflection mirror 20. Polygon mirror 30 as an optical scanning means for reflecting the laser light guided by the laser beam and continuously changing the emission direction thereof, and a light receiving lens 40 for condensing the reflected light of the laser light emitted through the polygon mirror 30 And a photodiode 50 as a light receiving element that receives the reflected light condensed by the light receiving lens 40 and converts the reflected light into an electric signal.

As shown in FIGS. 2 and 3, the lens unit 10 includes a laser diode 12 serving as a light emitting element for generating a pulsed laser beam in the infrared region, and a laser diode 12 for supplying power thereto. A light emitting circuit board 13 for generating a laser beam from the laser diode 12, and a lens unit 1 for making the laser beam generated by the laser diode 12 substantially parallel.
The collimator lens 14 includes a collimator lens 14 that emits light from a zero, and a unit housing 16 that holds these components 12, 13, and 14 and guides laser light from the laser diode 12 to the collimator lens 14.

The polygon mirror 30 has six reflecting surfaces H for reflecting the laser beam supplied from the lens unit 10 via the reflecting mirror 20, and the reflecting surface H is perpendicular to each of the reflecting surfaces H. (That is, the polygon mirror 3
The angle (the direction in the up-down direction) with respect to the direction of the rotation axis 0 is different from each other.

As shown in FIG. 1, the laser radar device 2
Has a plurality of electronic circuit boards in addition to the light emitting circuit board 13 as described below. That is, the laser radar device 2
Is a motor drive circuit board 60 for driving the polygon scanner motor 32 to rotate the polygon mirror 30.
A light-receiving circuit board 70 for amplifying and shaping an electric signal generated by the photodiode 50 and outputting it as a light-receiving signal; a light-emitting circuit board 13 and a motor driving circuit board 60
The above-described optical system is caused to perform scanning of laser light by operating the electronic circuits respectively configured on the optical circuit, while the scanning area is determined based on a light receiving signal from the light receiving circuit board 70 (ie,
A control circuit board 80 for performing various kinds of arithmetic processing for obtaining a distance to an object present in a laser light scanning area), and a light emitting circuit board 13, a motor drive circuit board 60, and a control circuit board 80, respectively. And a power supply circuit board 90 for supplying power to each electronic circuit.

The laser radar device 2 has a structure for holding and protecting the above-mentioned components at predetermined positions. That is, the laser radar device 2 has a front case 100 for accommodating each of the above components, and a laser radar device 2 that is formed to be insertable inside the front case 100 and holds the above components inside the front case 100 with high positional accuracy. An inner case 110 cast from aluminum and a rear case 120 for closing an opening at the rear of the front case 100 are provided.

On the front surface of the front case 100, an emission window 102 for emitting the laser light reflected by the polygon mirror 30 to the outside of the front case 100, and an entrance window for receiving the reflected light corresponding to the laser light. 104 are formed. An object (for example, a water drop or dust), which may cause a failure of the laser radar device 2 through the exit window 102 and the entrance window 104, is hereinafter referred to as "water drop or the like".
In this case, a window plate 130 made of a material capable of transmitting light blocks the exit window 102 and the entrance window 104 so as to block the exit window 102 and the entrance window 104 from entering the inside of the front case 100. It is arranged in. More specifically, the window plate 130 is attached to the front case 10.
The front case 100 is disposed between the front part of the inner case 110 and the front part of the front case 100 housed inside the front case 100. Note that the window plate 130 is formed of transparent glass or resin, and does not prevent light from passing through the exit window 102 and the entrance window 104.

A packing 140 with an O-ring is disposed between the window plate 130 and the front part of the front case 100 to prevent water droplets or the like from entering therethrough. The packing 140 with an O-ring is formed by integrally molding a rubber O-ring 142 having substantially the same shape as the exit window 102 and a rubber O-ring 144 having substantially the same shape as the entrance window 104. And inside the front part of the front case 100,
By pressing the inner case 110 through the packing 140 with the O-ring and the window plate 130, the hermeticity of the exit window 102 and the entrance window 104 is ensured.

On the other hand, an O-ring 146 is disposed between the front case 100 and the rear case 120 to prevent water droplets or the like from entering therethrough. A connector 150 for inputting / outputting a signal to / from the laser radar device 2 and supplying power to the laser radar device 2 is provided on an outer surface of the rear case 120.
It is inserted into the inside of the laser radar device 2 through the through-hole 122 of the zero. Then, the connector 150 and the rear case 1
An O-ring 148 for preventing water droplets or the like from entering through the through-hole 122 of the rear case 120 is disposed between the O-ring 148 and the O-ring 20.

The components of the optical system, such as the lens unit 10, the reflection mirror 20, the polygon mirror 30, the light receiving lens 40, and the photodiode 50, and the circuit boards 13 and
The lenses 60, 70, 80, and 90 are held inside the laser radar device 2 using the inner case 110 as a support (that is, held by the inner case 110). Of these, the lens unit 10 and the reflection mirror 20
The polygon mirror 30 is disposed in a space on the right side inside the laser radar device 2 as shown in FIG.

As shown in FIGS. 2 and 3, the space in which the lens unit 10, the reflection mirror 20 and the polygon mirror 30 are arranged is vertically divided by a partition wall 112 formed as a part of the inner case 110. . The lens unit 10 and the reflection mirror 20 are arranged in a space above the partition 112, and the polygon mirror 30 is arranged in a space below the partition 112. The partition 112 has
As shown in FIG.
An opening 118 for passing the laser light toward zero is formed.

The lens unit 10 includes a partition 112
Is fixed to the upper surface of the partition wall 112 by being screwed into the unit housing 16. A plurality of protrusions 115 for determining the position of the lens unit 10 are formed on the upper surface of the partition 112, and correspondingly, the unit housing 16 has a fitting hole that can be fitted with the protrusion 115. 18 are formed. When the fitting hole 18 of the unit housing 16 is externally fitted to the projection 115, the lens unit 10 is fixed on the inner case 110 so that laser light can be emitted in a certain direction.

Further, the reflection mirror 20 is provided in front of the lens unit 10 (that is, in the direction in which the laser beam is emitted when viewed from the lens unit 10).
Is fixed to the inner case 110. On the other hand, the polygon mirror 30 is attached to a rotating shaft of a polygon scanner motor 32 fixed to a motor drive circuit board 60 formed using a metal plate as a base substrate. The motor drive circuit board 60 is screwed to the inner case 1
10, the polygon mirror 30
The inner case 11 can rotate around a certain axis.
It will be held at 0.

Next, the electrical configuration of the laser radar device 2 of the present embodiment will be described with reference to FIG.
As shown in FIG. 4A, the laser radar device 2 is a microcomputer (hereinafter, referred to as a CPU) that performs a process for detecting a distance to an object existing in a scanning region of a laser beam and other various arithmetic processes. ) 160, a motor drive circuit 162 for driving the polygon scanner motor 32 according to a drive signal from the CPU 160, and the rotational position of the polygon scanner motor 32 (that is, the rotational position of the polygon mirror 30) has reached a predetermined reference position. Sometimes CPU16
3, a rotation position sensor 163 that outputs a reference position signal to
When the light emission command signal SO from the CPU 160 becomes an active level, power is supplied to the laser diode 12 (that is, the laser diode 12 is driven), and a pulsed laser beam (in this embodiment, A light emitting circuit 164 for generating a laser beam having a pulse width of about 30 ns); a light receiving circuit 166 for amplifying and waveform shaping the electric signal generated by the photodiode 50 and outputting it as a light receiving signal SI;
And a signal processing IC 168 to which the light emission command signal SO to the light receiving circuit 4 and the light receiving signal SI from the light receiving circuit 166 are input.

Then, the signal processing IC 168
As shown in (B), the light emission command signal SO from the CPU 160 is at an active level (high level in the present embodiment).
From this timing until the light receiving signal SI from the light receiving circuit 166 reaches the active level (that is, the level indicating that the photodiode 50 has received the laser beam, which is the high level in the present embodiment). The time T is measured, the measured time T is converted into digital data, and output to the CPU 160. Also, the CPU 160
Based on the digital data from the signal processing IC 168,
At least, a distance to an object present in the scanning region of the laser beam is calculated, and the result is calculated by an electronic control unit (for example, an electronic control for controlling the inter-vehicle distance) connected to the laser radar device 2 via the connector 150. Device) on a regular basis.

That is, the CPU 160 and the signal processing IC 1
Reference numeral 68 denotes a timing at which the laser diode 12 generates laser light (that is, an emission timing of laser light).
Based on the time difference T between the time when the laser light hits the object existing outside the device 2 and returns (that is, the time when the reflected light of the emitted laser light is received by the photodiode 50), the object outside the device 2 is The distance of is detected.

The signal processing IC 168 includes a CPU 160
If the light receiving signal SI from the light receiving circuit 166 does not become active level within a predetermined time limit after the light emitting command signal SO from the active level becomes active level, it indicates to the CPU 160 that distance measurement is impossible. Data (hereinafter referred to as distance-measureable data) is output. On the other hand, CPU
160 and the signal processing IC 168 are mounted on the control circuit board 80, the light emitting circuit 164 is mounted on the light emitting circuit board 13,
The light receiving circuit 166 is mounted on the light receiving circuit board 70, and the motor drive circuit 162 and the rotation position sensor 163 are mounted on the motor drive circuit board 60 together with the polygon scanner motor 32.

In the laser radar apparatus 2 of the present embodiment configured as described above, the CPU 160 drives the polygon scanner motor 32 via the motor drive circuit 162 to rotate the polygon mirror 30 at a constant speed. Further, based on the reference position signal from the rotation position sensor 163, the rotation position of the polygon mirror 30 is always grasped.

Further, as shown in FIG. 5A, the CPU 160 determines that each reflection surface H of the polygon mirror 30 is positioned above the polygon mirror 30 (specifically, from the surface direction orthogonal to the rotation axis of the polygon mirror 30). Look, front case 10
By outputting the active-level emission command signal SO to the light-emitting circuit 164 intermittently in a period immediately before and immediately after facing the emission window 102 of 0, the laser beam (laser pulse) is emitted to the laser diode 12 a predetermined number of times (laser pulse). In this embodiment, it is generated intermittently only 105 times.
FIG. 5A shows the laser radar device 2 similarly to FIG.
The arrangement of the components inside the device 2 is shown from above. In particular, the space where the polygon mirror 30 is arranged (the space on the right side inside the device 2) is the partition wall 11 described above.
2 shows a state lower than 2.

Then, each laser beam generated by the laser diode 12 is made substantially parallel by the collimator lens 14 and emitted to the reflecting mirror 20, where the reflecting mirror 2
After being reflected at 0 and passing through the opening 118 of the partition 112,
Of the six reflecting surfaces H of the polygon mirror 30, the light enters the reflecting surface H facing the exit window 102 at that time (FIG. 3).
(See the optical axis indicated by the one-dot chain line.)

Each laser beam reflected by the reflection surface H passes through the window plate 130 and is emitted from the emission window 102 to the outside of the laser radar device 2 as shown in FIG. However, since the direction of the reflection surface H of the polygon mirror 30 with respect to the emission window 102 differs at each timing when laser light is generated by the laser diode 12, the emission window 102
The laser light (laser pulse) is scanned and emitted in a predetermined angle range from the outside to the outside.

The laser light emitted from the emission window 102 to the outside is scanned in the horizontal direction on each reflection surface H of the polygon mirror 30 and is also scanned in the vertical direction for each reflection surface H. This is because, as described above, the directions of the respective reflecting surfaces H in the vertical direction are different from each other.

The laser beam emitted from the emission window 102 in this manner is applied to a vehicle or an object on the road, and the reflected light is applied to the front case 100 as shown in FIG.
When the light passes through the entrance window 104 and the window plate 130, and is further condensed by the light receiving lens 40 and reaches the photodiode 50, the light is converted into an electric signal by the photodiode 50. Then, the electric signal converted by the photodiode 50 is amplified and waveform-shaped by the light receiving circuit 166 and output to the signal processing IC 168 as the light receiving signal SI.

Then, the signal processing IC 168 and the CP
By U160, the distance from the emission window 102 to the object existing in the scanning region of the laser beam is calculated by the above-described procedure. Next, in the laser radar device 2 according to the present embodiment, the self-diagnosis is performed periodically to determine whether the light emitting function and the light receiving function of the laser beam are normal by the configuration described below and the self-diagnosis processing by the CPU 160. I am trying to do it.

First, in the laser radar device 2 of the present embodiment, as described above, the light emitting system components including the lens unit 10, the reflection mirror 20, and the polygon mirror 30 are arranged in the space on the right inside the device 2. In addition, a light receiving system component including the light receiving lens 40 and the photodiode 50 is arranged in the space on the left side inside the device 2.

The space on the right side where the light emitting system components are arranged (hereinafter referred to as light emitting side space) and the space on the left side where the light receiving system components are arranged (hereinafter referred to as light receiving side space) are basically Specifically, as shown in FIG.
10 are separated by a partition wall 116 configured as a part of the partition wall 10.
As shown in FIG. 5, a hole 117 is provided.

Further, in the laser radar device 2,
The direction of each reflecting surface H of the rotated polygon mirror 30 is
As shown in FIG. 5 (B), when the direction becomes a specific direction other than the direction for emitting the laser beam from the emission window 102,
When the laser diode 12 generates a laser beam, the laser beam is sequentially reflected by the reflection surfaces H of the reflection mirror 20 and the polygon mirror 30, passes through the hole 117 of the partition wall 116, and is further reflected by the window plate 130. , The photodiode 50.

That is, in the present laser radar device 2, when each reflection surface H of the polygon mirror 30 is oriented in the above-described specific direction, the laser beam from the laser diode 12 is emitted as shown by the dashed line in FIG. An optical path for self-diagnosis, which is reflected on the inner surface of the window plate 130 and reaches the photodiode 50, is formed.

In the laser radar apparatus 2, the CPU 160 executes the above-described processing for distance measurement (the processing for rotating the polygon mirror 30 at a constant speed and for driving the laser diode 12 to emit light). Thus, the self-diagnosis processing shown in FIG. 6 is executed.

That is, when the CPU 160 starts the self-diagnosis processing of FIG. 6, first, a step (hereinafter simply referred to as “S”) is performed.
At 110, it waits until the diagnosis execution timing comes.
The diagnosis execution timing is a timing at which the direction of each reflection surface H of the polygon mirror 30 is in the specific direction described above (the direction in which the self-diagnosis optical path of FIG. 5B is formed), and The determination is made based on the timing at which the reference position signal is output from the sensor 163 and the rotation speed of the polygon mirror 30.

When the CPU 160 determines that the diagnosis execution timing has come, it proceeds to S 120, in which the laser light is applied to the laser diode 12 via the light emitting circuit 164.
To generate times. Then, the CPU 160 further proceeds to S1
At 30, the reflected light of the laser light (hereinafter referred to as a test laser light) generated by the laser diode 12 at S120 reaches the photodiode 50 via the optical path for self-diagnosis in the device 2. It is determined whether or not the photodiode 50 has normally received the reflected light.

More specifically, in S130,
If the signal processing IC 168 outputs normal data that is not the distance measurement impossible data, an active level indicating that the reflected light of the test laser light has been received from the light receiving means including the photodiode 50 and the light receiving circuit 166. This means that the light receiving signal SI (corresponding to the signal indicating that the reflected light of the light beam has been received) is output, and it is determined that the photodiode 50 has normally received the reflected light of the test laser light. Conversely, if the distance measurement impossible data is output from the signal processing IC 168, the photodiode 50
And the light receiving means including the light receiving circuit 166 did not output the active level light receiving signal SI indicating that the reflected light of the test laser light was received. It is determined that the reflected light has not been received normally.

If it is determined in step S130 that the photodiode 50 has normally received the reflected light of the test laser beam, the process returns to step S110 and waits for the next diagnosis execution timing. On the other hand, if it is determined in step S130 that the photodiode 50 has not received the reflected light of the test laser beam normally, the light emitting unit including the laser diode 12 and the light emitting circuit 164, the photodiode 50 and the light receiving unit It is determined that at least one of the light receiving means including the circuit 166 is abnormal, and S
Go to 140. Then, in S140, abnormality determination processing such as setting a flag indicating occurrence of abnormality is performed, and thereafter, the flow returns to S110 to wait for the next diagnosis execution timing.

That is, if both the light emitting means including the laser diode 12 and the light emitting circuit 164 and the light receiving means including the photodiode 50 and the light receiving circuit 166 are normal, each reflection surface H of the polygon mirror 30 is identified as described above. When the laser beam is generated in the laser diode 12 when the direction of the laser beam is turned, the test laser beam is
The light arrives at the photodiode 50 via the self-diagnosis optical path in the inside, and the active-level light-receiving signal S from the light-receiving circuit 166.
I will be output. On the other hand, the laser diode 12, the light emitting circuit 164, the photodiode 50,
If any one of the light receiving circuit 166 and the light receiving circuit 166 is abnormal, even when the laser diode 12 emits laser light when each of the reflection surfaces H of the polygon mirror 30 is oriented in the specific direction,
The light receiving circuit SI receives an active level light receiving signal SI from the light receiving circuit 166.
Is not output.

Therefore, in this self-diagnosis processing, when each of the reflecting surfaces H of the polygon mirror 30 is oriented in the above-described specific direction, a laser beam is generated in the laser diode 12, and the active level light receiving signal SI is output from the light receiving circuit 166. If no light is output, it is determined that one of the light emitting means including the laser diode 12 and the light emitting circuit 164 and the light receiving means including the photodiode 50 and the light receiving circuit 166 is abnormal.

In the laser radar device 2 of the present embodiment, the front case 100 corresponds to a housing, and the exit window 102 and the entrance window 1 provided on the front surface of the front case 100 are provided.
04 corresponds to the window. The self-diagnosis processing of FIG. 6 executed by the CPU 160 corresponds to a self-diagnosis unit.

According to the laser radar device 2 of the present embodiment as described above, the light-emitting monitor light-receiving element 209 and the light-receiving monitor light-emitting element 2 as in the above-described conventional device 200 are used.
Even if the laser light source 10 is not provided, the operation state of the laser diode 12 and the light emitting circuit 164 for generating the laser light emitted to the outside and the photo for receiving the reflected light of the laser light emitted to the outside and converting it into an electric signal The self-diagnosis of the operating states of the diode 50 and the light receiving circuit 166 can be performed at the same time, and as a result, downsizing and cost reduction can be realized.

Moreover, the laser radar device 2 of the present embodiment
Instead of detecting the leaked light from the emission optical path as in the conventional device 200, the laser light generated by the laser diode 12 is used for the self-diagnosis during the self-diagnosis.
Since the laser beam reaches the photodiode 50 almost directly via the optical path for self-diagnosis, the accuracy of determining whether or not the emission operation of the laser beam is normal (ie, the determination accuracy of emission / non-emission) is increased. Can be.

In the laser radar device 2 of the present embodiment, the light-transmitting window plate 130 provided continuously over both the exit window 102 and the entrance window 104 is provided inside the front part of the front case 100. Since the laser light is used as a part of the optical path for self-diagnosis, the laser light reflected by the reflection surface H of the polygon mirror 30 reaches the photodiode 50 in the front case 100 during the self-diagnosis of light emission and light reception. There is no need to separately provide members. Therefore, it is more advantageous in terms of size reduction and cost reduction.

Although the embodiment of the present invention has been described above, it goes without saying that the present invention can take various forms. For example, in the laser radar device 2 of the above embodiment, the self-diagnosis of light emission and light reception is performed every time each reflection surface H of the polygon mirror 30 is in the specific direction. For example, the measurement may be performed every time one of the reflection surfaces H of the polygon mirror 30 is oriented in the specific direction. In this case, the self-diagnosis is performed once each time the polygon mirror 30 makes one rotation.

The laser radar device 2 of the above embodiment
Was provided with a polygon mirror 30 rotated in a fixed direction as an optical scanning unit. However, the present invention provides, for example, a single scanning mirror having only one reflection surface as an optical scanning unit. In addition, the present invention can be similarly applied to a reflection measuring device in which the scanning mirror is reciprocated for so-called swing scanning.

Further, the present invention can be applied not only to a vehicle-mounted device but also to a reflection measuring device such as a laser radar device for other uses.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating a configuration of a scanning laser radar device according to an embodiment.

FIG. 2 is a diagram illustrating a configuration of the scanning laser radar device according to the embodiment from above.

FIG. 3 is a diagram illustrating the configuration of the scanning laser radar device according to the embodiment from the right.

FIG. 4 is a diagram illustrating an electrical configuration of the scanning laser radar device according to the embodiment.

FIG. 5 is a diagram illustrating an operation of the scanning laser radar device according to the embodiment.

FIG. 6 is a flowchart illustrating a self-diagnosis process executed by a CPU in the scanning laser radar device according to the embodiment.

FIG. 7 is a configuration diagram illustrating a configuration of a conventional reflection measurement device.

[Explanation of symbols]

2 laser radar device (reflection measuring device), 12 laser diode, 20 reflection mirror, 30 polygon mirror, H reflection surface, 32 polygon scanner motor, 40
.., Light receiving lens, 50, photodiode, 100, front case, 102, exit window, 104, entrance window, 110
... inner case, 116 ... partition wall, 117 ... hole (hole forming self-diagnosis path), 120 ... rear case, 13
0: window plate, 160: CPU (microcomputer),
162: motor drive circuit, 163: rotational position sensor, 1
64 light emitting circuit, 166 light receiving circuit, 168 signal processing IC

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takeka Terui 1-1-1 Showa-cho, Kariya-shi, Aichi F-term in DENSO Corporation (Reference) 2F065 AA06 CC11 DD02 DD08 FF12 GG04 GG12 JJ01 JJ18 LL00 LL12 LL15 LL61 MM16 UU05 UU06 UU07 2F112 AD01 BA10 BA15 CA05 DA15 DA32 DA40 FA45 GA10 5J084 AA02 AA05 AB01 AC02 AD01 BA03 BA36 BA49 BB04 BB26 CA03 CA14 CA15 CA76 DA07 EA16 EA20 EA40

Claims (2)

[Claims] A light-emitting means for generating a light beam; and a reflecting surface for reflecting the light beam generated by the light-emitting means, inside the housing having a window provided on a front surface thereof. An optical scanning unit that scans a light beam from the light emitting unit and emits the light beam from the window unit to the outside of the housing by regularly changing an orientation with respect to the window unit; and a light beam emitted from the window unit. Light-receiving means for receiving reflected light of the light-emitting means and the light scanning means for scanning and emitting a light beam from the window to the outside of the housing, and reflecting the reflected light of the emitted light beam. In a reflection measurement device that receives information from a light receiving unit and detects information about an object present in an emission direction of the light beam, a direction of a reflection surface of the light scanning unit is set in the housing. Running light beam When the light emitting means generates a light beam when the light beam is emitted in a specific direction other than the direction for emitting the light beam to the outside of the housing when the light beam is emitted, the light beam is scanned by the light beam. There is an optical path for self-diagnosis that is reflected by a reflection surface of the means and then reflected at a predetermined position in the housing and reaches the light receiving means. Further, the reflection surface of the light scanning means has the specific orientation. A light beam is generated in the light emitting means, and by monitoring whether or not a signal indicating that the reflected light of the light beam is received is output from the light receiving means, the light emitting means and the light receiving means are monitored. A self-diagnosis means for diagnosing an operation state of the reflection measuring device. 2. The reflection measurement apparatus according to claim 1, wherein the window of the housing receives an emission window for emitting a light beam, and receives reflected light of the light beam emitted from the emission window. And an incident window for the reflected light to be received by the light receiving means, and inside the housing, the exit window and the incident window are provided with a continuous window plate capable of transmitting light. The specific direction is a direction in which the light beam generated by the light emitting unit and reflected by the reflection surface of the light scanning unit is reflected by the window plate and reaches the light receiving unit. A reflection measuring device.