JP2016038211A - Laser radar device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a novel laser radar device that does not require the mechanical scanning of laser luminous flux.SOLUTION: The laser radar device has: a laser luminous flux projection unit 10 for radiating n(≥2) divergent laser luminous fluxes in shape of a fan with an angle of aperture θ so that they do not separate from each other; laser light receiving units 310 and 320 for receiving return laser light radiated from the laser luminous flux projection unit and reflected by an object in such a way as to be able to identify the bearing of the object; a control arithmetic unit 61 for controlling the laser luminous flux projection unit and the laser light receiving units, identifying the bearing of the object that reflected the return laser light and a distance to the object from the light reception information of the laser light receiving units, and outputting the identified bearing and distance; and a display unit 62 for displaying the output of the control arithmetic unit.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a laser radar device.

  Various laser radar devices have been proposed and are known.

  In the laser radar device, a laser beam is emitted, and reflected laser light from an object is detected to specify “the direction of the object and the distance to the object”.

  In a conventionally known laser radar apparatus, a laser beam is scanned one-dimensionally or two-dimensionally to irradiate an object, and laser light reflected by the object is received by a light receiving element and detected.

  Then, the distance to the object is specified by “the time required for the laser light to travel back and forth the distance to the object”.

  Since the laser beam is scanned, the direction of the laser beam when reflected by the object can be determined from the change in the direction of the laser beam accompanying the scanning, and the “azimuth of the object” can be specified.

  Many conventional laser radar devices mechanically scan a laser beam with scanning means such as a rotary polygon mirror or a peristaltic mirror, and adjustment of the scanning means is necessary.

  Also, a space for arranging mechanical scanning means is required.

  A “method of avoiding a collision” using a plurality of laser beams is known (Patent Document 1).

  An object of the present invention is to realize a novel laser radar apparatus that does not require mechanical scanning of a laser beam.

  The laser radar device according to the present invention radiates n (≧ 2) divergent laser beams in a fan shape with an opening angle: θ so as not to be separated from each other, and radiates from the laser beam projection unit The laser beam receiving unit that receives the return laser beam reflected by the object so that the direction of the object can be specified, the laser beam projection unit, and the laser beam receiving unit are controlled, and the light reception information of the laser beam receiving unit Thus, a control calculation unit that specifies and outputs the azimuth of the object that reflected the return laser beam and the distance to the object, and a display unit that displays the output of the control calculation unit.

  According to the present invention, a novel laser radar device that does not require mechanical scanning of a laser beam can be realized.

It is a figure for demonstrating one example of the laser beam projection part in 1st Embodiment of a laser radar apparatus. It is a figure for demonstrating one example of the laser beam light-receiving part in 1st Embodiment of a laser radar apparatus. It is a figure for demonstrating one example of the laser beam light-receiving part in 1st Embodiment of a laser radar apparatus. It is a figure for demonstrating one Embodiment of a laser beam projection part. It is a figure for demonstrating another form of implementation of a laser beam projection part. It is a figure for demonstrating the laser beam projection part of other form of implementation of a laser radar apparatus. It is a figure for demonstrating the laser beam projection part of FIG. It is a figure which shows the system diagram of a laser radar apparatus. It is a figure for demonstrating the principle of a laser radar apparatus.

  Prior to the description of the embodiment of the invention, the principle part will be described with reference to FIG.

  FIG. 9 is a principle explanatory view of “a laser radar device that does not mechanically deflect a laser beam”.

  In FIG. 9A, reference numeral 1 denotes a “laser beam projection unit”.

  As shown in the figure, the laser beam projection unit 1 radiates a divergent laser beam OL in a “fan-shaped shape with an opening angle of θ”. That is, the laser beam OL is diverged in a fan shape with an opening angle: θ.

  For the purpose of explanation, the laser beam projection unit 1 is mounted on a vehicle and emits a “divergent laser beam” toward the front of the vehicle, and the plane of FIG. 9A is parallel to the ground. It ’s a good face.

  The divergent laser beam OL diverges in a fan shape in a plane parallel to the ground, but does not substantially diverge in the direction orthogonal to the drawing, and the two beam surfaces orthogonal to the drawing are parallel to each other. Suppose there is.

  That is, the laser light beam OL is diverged in a fan shape with an opening angle: θ in a plane parallel to the ground.

  The distance DL in FIG. 9A is the maximum distance (hereinafter referred to as “effective projection distance”) that can be effectively detected with respect to an object to be detected (such as another vehicle).

  In FIG. 9B, reference numeral 3 denotes a “laser light receiving portion”.

  The laser light receiving unit 3 is separate from the laser beam projection unit 1, but is disposed in the vicinity of the laser projection position, and includes an imaging lens 31 as a “condensing unit” and an optical position sensor 32.

  The optical position sensor 32 is, for example, an “imaging device” such as a CMOS sensor or a CCD sensor, and is arranged such that its light receiving surface coincides with the image side focal plane of the imaging lens 31.

In FIG. 9B, the symbol Ob indicates “an object to be detected (hereinafter referred to as“ test object ”)” such as another vehicle or an obstacle.
When the detection object Ob enters the projection region of the laser beam OL within the effective projection distance, the laser beam OL is reflected by the detection object Ob, and a return laser beam BKL toward the laser beam receiving unit 3 is generated.

  In the “general detection situation” of the detection object Ob, the distance between the detection object Ob and the imaging lens 31 is sufficiently larger than the focal length of the imaging lens 31.

  Therefore, the return laser beam BKL incident on the imaging lens 31 is a “substantially parallel light beam” and is condensed on the “light receiving surface of the optical position sensor 32” that coincides with the image side focal plane of the imaging lens 31 ( Image).

  As shown in FIG. 9C, the distance between the condensing position of the return laser beam BKL and the optical axis AX of the imaging lens 31 is “x”, and the focal length of the imaging lens 31 is “h”.

  Distance: x can be known from the output of the optical position sensor 32.

Then, the direction (angle: α) in which the detection object Ob exists is
tan α = X / h
From
Angle: α = arctan (X / h)
Can be calculated arithmetically as follows.

  On the other hand, as shown in FIG. 9B, the distance along the return laser beam BKL from the detection object Ob to the light receiving surface of the optical position sensor 32 is defined as “D0”.

  The distance: D0 can be obtained by knowing the time from when the laser beam is emitted from the laser beam projection unit 1 until it is received by the optical position sensor 32.

  For the sake of concreteness of description, the laser beam projection unit 1 and the laser beam receiving unit are set so that the distance from the laser beam projection unit 1 to the detection object Ob is equal to the distance from the detection object Ob to the optical position sensor 32. Assume that the positional relationship of 3 is set.

  Assuming that the time from when the laser beam OL radiated from the laser beam projection unit 1 is reflected by the detection object Ob to become the return laser beam BKL and detected by the optical position sensor 32 is “2T”, the speed of light is “C”. The distance: D0 is obtained as “C · T”.

  In this way, the azimuth: α and the distance: D0 of the detection object Ob are obtained.

  For the sake of simplicity, the optical position sensor 32 is assumed to be an “imaging device such as a CMOS sensor or a CCD sensor”. Described as what to do.

  However, the laser light receiving unit has two parts, one used for measuring the direction and the other used for measuring the distance. The "image sensor" is used for measuring the direction, and the distance is measured. It is practical to use APD (avalanche photo diode) or the like.

The above is a description of the principle, and there are various limitations when actually implemented.
First, since the projected laser beam OL is diverged in a “fan-shape having an opening angle: θ”, the intensity of the laser beam OL is rapidly attenuated with the distance from the laser beam projection unit 1.

  For this reason, the “effective projection distance: DL” by which the laser beam receiving unit 3 can receive the return laser beam BKL having “distance: D0 and direction: intensity capable of measuring α” is limited to a short distance.

  In order to increase the effective projection distance, a “high-power laser light source” is required in the laser beam projection unit.

  In addition, it is difficult to increase the “accuracy for detecting the direction” as compared with the method of scanning the laser beam.

  Embodiments of the invention will be described below.

  FIG. 1 is a diagram for explaining an example of a “laser beam projection unit” in the first embodiment of the laser radar apparatus of the present invention.

  FIG. 1A shows a state in which n (≧ 2) divergent laser light beams L1 to L5 are emitted from the laser light beam projection unit 10 in a fan shape with an opening angle of θ. It is shown in an explanatory manner.

  The distance shown in FIG. 1A: DLM indicates “effective projection distance”, that is, “maximum distance at which a detection target can be detected” by the laser radar device.

  Further, in the embodiment shown in FIG. 1, the divergent laser beams L1 to L5 are “sequentially emitted in time series”.

  The laser beam projection unit 10 includes n (= 5) laser light sources and one or more beam conversion optical systems that use laser light emitted from each of the n laser light sources as a divergent laser beam.

  Further, it has “beam combining means” for arranging n (= 5) divergent laser light beams L1 to L5 by the light beam conversion optical system in a fan shape with an opening angle: θ.

  Specific examples of these “laser light source, optical element, beam combining means” will be described later.

  The five laser light sources are driven to blink by “different light emission pulses” as shown in FIG. 1B, for example, and sequentially blink in time series.

  Due to this time-series flashing, the divergent laser beams L1 to L5 are sequentially emitted.

  These divergent laser beams L1 to L5 are arranged in a fan shape with an opening angle: θ as shown in FIG.

  The “fan-shaped array” of the divergent laser beams L1 to L5 is an array in which the divergent laser beams are not separated from each other.

  That is, the laser beam projection unit 10 shown in FIG. 1 radiates five divergent laser beams in a fan shape with an opening angle: θ so as not to “separate from each other”.

  For the sake of concreteness of explanation, it is assumed that the laser beam projection unit 10 shown in FIG. 1 is also mounted on the vehicle and emits a divergent laser beam L1 and the like toward the front of the vehicle, and the surface of FIG. A plane parallel to the ground.

  A little supplementary explanation.

  In the embodiment described above with reference to FIG. 1, five divergent laser beams L <b> 1 to L <b> 5 are sequentially emitted in time series from the laser beam projection unit 10.

  Therefore, if each of these five divergent laser beams L1 to L5 is sequentially emitted, the emitted divergent laser beam is “any one of the five”.

  However, the five divergent laser beams L1 to L5 are radiated in a fan shape with an opening angle of θ as shown in FIG. 1A as a whole.

  That is, in general, n (≧ 2) divergent laser beams are “radiated in the shape of a fan with an opening angle of θ”. As a fan-like pattern.

  Further, the n divergent laser beams emitted in a fan shape do not necessarily need to be “arranged in a fan shape within the same plane”.

  When viewed from a direction perpendicular to the drawing of FIG.

  Of course, even in this case, the divergent laser beams are close to each other in the direction orthogonal to the drawing.

  As described above, the n divergent laser beams are arranged in a fan shape having an opening angle of θ so as not to be separated from each other.

  The phrase “not separated from each other” here is not a strict meaning, and even if they are slightly separated from each other, “separation” to the extent that does not hinder the measurement of the azimuth and distance is allowed.

  In addition, since it is “not separated from each other”, it is allowed that adjacent divergent laser beams overlap each other as long as “there is no problem in detecting the direction and distance”.

  Next, the “divergence” of the divergent laser beam will be supplemented.

  In the laser radar device of the present invention, n divergent laser beams are emitted in a fan shape with an opening angle of θ.

  In other words, a fan-shaped array having an opening angle: θ is determined by “array as a whole” of n divergent laser beams.

  Number of divergent laser beams: Since n is 2 or more, the minimum number of divergent laser beams forming a fan-shaped array is two.

  Since the n divergent laser beams are arranged in a fan shape so as not to be “separated from each other”, if n divergent laser beams having the same divergence angle are arranged, the minimum value of the divergence angle is θ / n. If n = 2, the divergence angle is θ / 2.

  When the opening angle θ is 50 degrees, for example, the divergence angle of the two divergent laser beams is at least 25 degrees. The use of two divergent laser beams having a large divergence angle is effective in the case of a laser radar apparatus having a relatively short effective projection distance: DLM.

  If the opening angle θ in the fan-shaped array is about 20 degrees, for example, if the detection range of the laser radar device is “a limited opening angle area in front”, the divergence is 10 degrees. Using two laser beams, it is possible to detect an object up to a considerable effective projection distance.

  As described above, the divergence angle of the divergent laser beam and the number of divergent laser beams: n depend on the opening angle of the fan-like array of divergent laser beams: θ, that is, the spread angle at which an object is to be detected. Thus, a suitable one can be selected.

  A further supplement will be made regarding the divergence of the divergent laser beam.

  In the “principal description” described with reference to FIG. 9, the divergent laser beam OL diverges in a fan shape within a plane parallel to the ground, but substantially in a direction orthogonal to the drawing. Two light beam planes that are parallel and do not diverge substantially and are orthogonal to the drawing are substantially parallel to each other.

  This is because the energy of the laser beam is “effectively concentrated” in the direction orthogonal to the drawing.

  However, the present invention is not limited to this, and instead of a “parallel beam” in a direction orthogonal to the drawing of FIG. 9, a divergent state in which a predetermined “size of a detection target” is obtained at a predetermined distance may be used.

  When n divergent laser beams are used as in the laser radar apparatus of the present invention, when n is small and the opening angle of the fan-shaped array is large, θ, the divergence angle of the divergent laser beam is also Can be bigger.

  In such a case, it is preferable to reduce the divergence angle of each divergent laser beam in a direction orthogonal to the fan-shaped array surface.

  However, when the number of light beams: n is sufficiently large with respect to the opening angle: θ and the divergence angle of each divergent laser light beam is not large, it is necessary to reduce the divergence angle even in the direction orthogonal to the fan-shaped array surface. Is not necessarily.

  In the embodiment of FIG. 1, the divergent laser beams L1 to L5 are radiated with a slight upward angle from a direction parallel to the ground GR, as shown in FIG.

  For example, when the laser radar device is mounted and used in a light vehicle or a small vehicle, it is conceivable to attach the laser beam projection unit 10 to the lower part of the bonnet.

  In this case, as shown in FIG. 1C, the divergent laser beams L1 to L5 are preferably projected slightly upward with an angle of about several degrees with respect to the ground GR.

  Further, when the laser radar device is used by being mounted on a large vehicle such as an SUV or a truck, it is conceivable that the mounting position of the laser beam projection unit 10 is higher than the ground GR.

  In such a case, it is preferable that the projecting direction of the divergent laser beam is slightly downward (several degrees) from the direction parallel to the ground GR.

  In any case, the projecting direction of the divergent laser light beams L1 to L5 from the laser light beam projection unit 10 is “basically parallel to the ground GR”, and is appropriate depending on the specific use situation of the laser radar device. You can select the direction.

  In other words, when a laser radar device is mounted on a vehicle, there is an appropriate angle (about several degrees) in relation to the type of vehicle to be mounted, the vehicle to be detected, and a sign. Good.

  FIG. 1 (d) illustrates the state of FIG. 1 (c) as viewed from the right side of the figure, and the divergent laser beams L1 to L5 have the same divergence angles. .

  Next, an example of a “laser light receiving unit” used in combination with the laser beam projection unit 10 of FIG. 1 will be described with reference to FIG.

  In FIG. 2A, reference numeral 310 denotes an “azimuth detecting light receiving unit” that forms part of the laser light receiving unit, and includes an imaging lens 301 and an optical position sensor 302.

  Symbols ObA, ObB, and ObC in FIG. 2A indicate “detection objects” such as other vehicles and obstacles.

  As shown in FIG. 2A, the detection objects ObA and ObB are in the irradiation region of the divergent laser beam L3, and the detection object ObC is at the boundary between the divergent laser beams L4 and L5.

  The imaging lens 301 receives the return laser beam reflected by each detection object, and condenses (images) it on the optical position sensor 302 having the light receiving surface matched with the image-side focal plane.

  Each return laser beam is focused (imaged) at a different position on the light receiving surface of the optical position sensor 302, and the orientations of the detection objects ObA, ObB, ObC are detected by the method described above with reference to FIG. The

  FIG. 2B shows a state of the light receiving surface 302 </ b> A of the optical position sensor 302.

  The light receiving surface 302A corresponds to the divergent laser light beams L1 to L5 in the left-right direction in the figure, and the return laser light beam in each of the divergent laser light beams L1 to L5 is at the light receiving surface position corresponding to each divergent laser light beam. Condensate.

  In FIG. 2B, symbols ObA, ObB, and ObC illustrate the state in which the return laser beam from the detection objects ObA, ObB, and ObC forms an image on the light receiving surface 302A.

  The output of the “cc cross section” on the light receiving surface 302A is as shown in FIG. In this figure, symbols ObA, ObB, and ObC indicate outputs corresponding to these detection objects.

  In this case, the detection objects ObA and ObB are in the projection region of the same divergent laser beam L3, but the detection object ObB is closer to the azimuth detection light receiving unit 310.

  Therefore, the intensity of the return laser beam from the detection object ObB is stronger than the intensity of the return laser beam from the detection object ObA.

  Accordingly, the output intensity of the optical position sensor 302 is as shown in FIG. 2C, and the detection objects ObA and ObB can be distinguished from each other according to the magnitude of the output intensity.

  That is, even if a plurality of detection objects are irradiated with the same divergent laser beam, the detection object can be specified by the strength of the output of the optical position sensor 302, and the orientation of the specified detection object can be known.

  As described above, the optical position sensor 302 is for obtaining the orientation of the “detection object reflecting the return laser beam” by the imaging position (condensing position) of the return laser beam, specifically, An image sensor such as a CCD sensor or a CMOS sensor is used.

FIG. 2D illustrates the laser light receiving unit in an explanatory manner.
Reference numeral 320 in the figure denotes a “distance measuring light receiving unit”, which includes a condensing lens 303, a light receiving element 304, and a condensing means 305.

  The distance measuring light receiving unit 320 takes in the return laser beam by the condensing lens 303, guides it to the light receiving surface of the light receiving element 304 by the condensing unit 305, and converts it into a signal by the light receiving element 304.

  The condensing means 305 is an “optical member having a frustoconical inner peripheral surface as a reflecting surface”, and the return laser beam captured by the condensing lens 303 is reflected by the reflecting surface to the light receiving element 304. Light guide. As the light receiving means 305, the above-mentioned APD can be suitably used.

  The azimuth detecting light receiving section 310 and the distance measuring light receiving section 320 are arranged adjacent to each other in the illustrated example.

  The adjacent aspect is arbitrary, and may be adjacent in the direction orthogonal to the drawing in addition to the illustrated aspect.

  In addition, the azimuth detecting light receiving unit 310 and the distance measuring light receiving unit 320 may be formed separately and adjacent to each other, but may not be in contact with each other and may be close to each other.

  In short, it is only necessary that the azimuth detecting light receiving unit 310 and the distance measuring light receiving unit 320 are close to each other to the extent that it is not necessary to distinguish them from the return laser beam.

  Of course, the azimuth detecting light receiving unit 310 and the distance measuring light receiving unit 320 may have a “structure integrated as a whole”.

  In the example in the description, the five divergent laser beams L1 to L5 are sequentially emitted in time series.

  Therefore, it is known which of the divergent laser beams L1 to L5 is the return laser beam Li (i = 1 to 5) detected by the distance measuring light receiving unit 320.

  The direction of the return laser beam is specified by the direction detection light receiving unit 310.

  The “distance” of the object to be detected that reflected the return laser beam is the time from the moment when the divergent laser beam: Li is emitted to the time when the return laser beam is detected by the light receiving element 304, as described above. , “CT”.

  In this way, the azimuth and distance of the detection object can be obtained.

  FIG. 3 is a diagram for explaining another embodiment of the laser light receiving unit.

  In FIG. 3A, reference numeral 330 indicates a “laser light receiving unit”.

  The laser light receiving unit 330 includes an imaging lens 305 and a light receiving element array 306.

  As shown in FIG. 3B, the light receiving element array 306 is configured by an array arrangement of five light receiving elements PD1 to PD5 according to the five divergent laser beams L1 to L5.

  The five light receiving elements PD1 to PD5 are independent of each other.

  That is, the light receiving elements PD1 to PD5 are “controllable independently of each other”. As a specific example of the light receiving element PDi, APD is suitable.

  The light receiving element PDi (i = 1 to 5) is an element that converts the intensity (light quantity) of received light into a signal.

  The light receiving elements PDi (i = 1 to 5) are arranged such that their light receiving surfaces coincide with the image side focal plane of the imaging lens 305.

  Then, when the object to be detected reflects the divergent laser beam Li, the reflected light returns to become a laser beam, and is focused (imaged) on the light receiving surface of the light receiving element PDi by the imaging lens 305. The positional relationship between the lens 305 and the light receiving element array 306 is determined.

  Therefore, the state in which the return laser beam is focused on the light receiving element PDi means that the return laser beam is due to the divergent laser beam Li.

  At this time, if the time from the moment when the divergent laser beam Li is emitted to the moment when the divergent laser beam Li is received is measured by the output of the light receiving element PDi: 2T, the detection target that reflects the divergent laser beam Li is reached. Distance: Can know CT.

  Further, the state where the light receiving element PDi returns and receives the laser beam means that the detection target is within the irradiation region of the divergent laser beam Li.

  Therefore, in this case, the radiation direction of the divergent laser beam Li can be used as the “rough azimuth” of the detection target.

  In this way, the “accuracy related to the direction” of the detection target becomes slightly rough, but the “rough direction and the accurate distance” of the detection target can be known by one laser light receiving unit 330.

  In this case, the following can be considered as a method for improving the “accuracy with respect to the direction of the detection target”.

  The first is a method of increasing the “number of light receiving elements corresponding to one” of the divergent laser beam.

  For example, if there are three light receiving elements corresponding to one divergent laser beam Li and a total of 15 light receiving elements are arranged in a line on the image side focal plane of the imaging lens 305, the detection object The accuracy with respect to the azimuth can be increased to three times that in the case of FIG.

  As another method, there is a method of increasing n while making the number of divergent laser beams: n equal to the number of light receiving elements: n.

  If it does in this way, the divergence angle of each divergent laser beam will become small, and the precision to the direction of a detection subject will also improve.

  As a third method, a method of increasing the number of light receiving elements corresponding to one divergent laser beam while increasing the number of divergent laser beams: n can be considered. Even if it does in this way, the precision regarding the azimuth | direction of a detection target object can be raised.

  If a light receiving element array is configured using a plurality of independent light receiving elements PD1 and the like as in the laser light receiving unit 330 shown in FIG. 3, the individual light receiving elements are independent and can be controlled independently of each other.

  Accordingly, the five divergent laser beams L1 to L5 can be “flashed simultaneously” to detect a detection target in a fan-shaped area having an opening angle: θ.

  Specific examples will be described below.

"Example 1"
As Example 1, a specific example in the case described above with reference to FIGS. 1 and 2 will be described.

  In FIG. 1, the effective projection distance: DLM is set to 200 m, and the measurement angle: θ is set to 50 degrees.

  A semiconductor laser (hereinafter abbreviated as “LD”) is assumed as the laser light source, and a case where “intensity necessary for measurement (light quantity per unit area)” is secured at a distance of 200 m is assumed.

  Further, 0.074 degrees is assumed as the horizontal resolution. This is “like a VGA class camera”.

  As a result of an experiment, it was found that when a laser beam having an intensity necessary for measurement was obtained from one LD at a distance of 200 m, the divergence angle should be approximately 10 degrees.

  Then, in order to arrange the divergent laser beams having an opening angle of 50 degrees (the above measurement angle) “without being separated from each other”, five divergent laser beams with a divergent angle of 10 degrees are required. .

  Therefore, a laser beam projection unit as shown in FIG. 4 was prepared using five LDs as laser light sources.

  FIG. 4A shows a portion that emits the divergent laser beams L1, L3, and L5.

The three LDs 11, 13, and 15 are arranged in the holding housing H1 as shown in the figure.
The “upper surface in the drawing” of the holding housing H1 is released, and the divergent laser beams L1, L3, and L5 are emitted.

  Coupling lenses CL1, CL3, CL5 and mirrors M1, M2 are also arranged in the holding housing H1.

  The laser beams emitted from the LDs 11, 13, and 15 are divergent and are converged into light beams by the corresponding coupling lenses CL1, CL3, and CL5.

  Then, after focusing, a “divergent laser beam having a divergence angle of approximately 10 degrees” is obtained. The laser beam from the LD 11 is reflected by the mirror M1 to become a divergent laser beam L1.

  The laser beam from the LD 13 becomes a divergent laser beam L3 after convergence. The laser beam from the LD 15 is reflected by the mirror M2 to become a divergent laser beam L5.

  In this way, three divergent laser beams L1, L3, and L5 are emitted from the holding housing H1.

  FIG. 4B shows a portion that emits the divergent laser beams L2 and L4.

The two LDs 12 and 14 are arranged as shown in the holding housing H2.
The upper surface of the holding housing H2 in the drawing is released, and the divergent laser beams L2 and L4 are emitted.

  Coupling lenses CL2 and CL4 and mirrors M3 and M4 are also disposed in the holding housing H2.

  The laser light emitted from the LDs 12 and 14 is divergent and is converted into a focused light beam by the corresponding coupling lenses CL2 and CL4.

  Then, after focusing, a “divergent laser beam having a divergence angle of approximately 10 degrees” is obtained.

  The laser beam from the LD 12 is reflected by the mirror M3 to become a divergent laser beam L2.

  The laser beam from the LD 14 is reflected by the mirror M4 to become a divergent laser beam L5.

  In this way, two divergent laser beams L2 and L4 are emitted from the holding housing H2.

  The holding housings H1 and H2 are overlapped as shown in FIG. 4C, and the divergent laser beams L1 to L5 emitted from these are shown in FIG. 1A when viewed from the upper side of FIG. In such a manner, it is arranged in such a “opening angle: θ = 50 degrees fan shape”.

  As shown in the figure, the divergent laser beams L1, L3, and L5 and the divergent laser beams L2 and L4 are not in the same plane, but the plane on which they are arranged is close to the vertical direction in FIG. doing.

  Effective projection distance: Since the DLM is as long as 200 m, even if the divergent laser beams L1, L3, L5, L2, and L4 are not in the same plane, the effective projection distance is a state in which the detection target near the DLM is irradiated. Then, these irradiation areas substantially overlap and become the same area.

  That is, the “laser beam projection unit” shown in FIG. 4 emits five divergent laser beams L1 to L5 in a fan shape with an opening angle of θ (= 50 degrees) so as not to be separated from each other.

  The five LDs 11 to 15, five coupling lenses CL 1 to CL 5 that convert the laser beams from the five laser light sources into five divergent laser beams, and five coupling lenses 5. Beam combining means M1 to M4, H1, and H2 for arranging the divergent laser light beams L1 to L5 in a fan shape with an opening angle of θ are provided.

  The coupling lenses CL1 to CL5 are “a beam conversion optical system that converts laser beams from five laser light sources into five divergent laser beams”.

  On the other hand, the laser light receiving unit is configured as shown in FIG.

  As the optical position sensor 302 of the azimuth detection light receiving unit 310, a CMOS sensor having 680 pixels in the horizontal direction in the figure was used.

  As the light receiving element 304 of the distance measuring light receiving unit 320, an APD is used, and as shown in FIG. 2D, a light collecting element 305 is used to increase the amount of light received by the light receiving element 304.

  The five LD 11 to LD 15 of the laser beam projection unit are driven to blink by “different light emission pulses” as illustrated in FIG. 1B and blink in time series.

  That is, the laser light sources LD11 to LD15 were pulsed in this order.

The time for one LD to emit light was set to 2 μsec, and 10 μsec was set as one cycle, which was repeated a plurality of times.
Assuming that the detection target is at a position of 200 m, the divergent laser light beam that irradiates the detection target returns to the optical position sensor 304 and passes through a distance of 400 m.

  If the speed of light is 300,000 km / s, the time required to pass 400 m is 1.33 μsec (<2 μsec), and the laser beam is detected within the radiation time of one divergent laser beam (2 μsec). It is possible enough.

  As described above, it was possible to detect the detection target (vehicle, obstacle, etc.) 200 m ahead in both direction and distance.

"Example 2"
As Example 2, a specific example in the case described above with reference to FIGS. 1 and 3 will be described.

  As in Example 1, the effective projection distance: DLM was 200 m, and the measurement angle: θ was 50 degrees.

  Divergence angle: A “laser beam projection unit” for realizing divergent laser beams L1 to L5 of 10 degrees was configured as shown in FIG. In order to avoid confusion, the same reference numerals as in FIG. 4 are used for those that are not likely to be confused.

  FIG. 5A shows a portion that emits the divergent laser beams L1, L3, and L5.

The three LDs 11, 13, and 15 are arranged in the holding housing H1 as shown in the figure.
The upper surface of the holding housing H1 in the drawing is released, and the divergent laser beams L1, L3, and L5 are emitted.

  Coupling lenses CL1, CL3, CL5 and mirrors M1, M2 are also arranged in the holding housing H1.

  The laser light emitted from the LDs 11, 13, and 15 is divergent, and the divergent property is suppressed by the corresponding coupling lenses CL1, CL3, and CL3, and becomes a divergent laser beam having a divergence angle of about 10 degrees.

  The laser beam from the LD 11 is reflected by the mirror M1 to become a divergent laser beam L1.

The laser beam from the LD 13 becomes a divergent laser beam L3.
The laser beam from the LD 15 is reflected by the mirror M2 to become a divergent laser beam L5.

  In this way, three divergent laser beams L1, L3, and L5 are emitted from the holding housing H1.

  FIG. 5B shows a portion that emits the divergent laser beams L2 and L4.

The two LDs 12 and 14 are arranged as shown in the holding housing H2.
The upper surface of the holding housing H2 in the drawing is released, and the divergent laser beams L2 and L4 are emitted.

  Coupling lenses CL2 and CL4 and mirrors M3 and M4 are also disposed in the holding housing H2.

  The laser light emitted from the LDs 12 and 14 is divergent, and the divergent property is suppressed by the corresponding coupling lenses CL2 and CL4, so that a divergent laser beam having a divergence angle of about 10 degrees is obtained.

  The laser beam from the LD 12 is reflected by the mirror M3 to become a divergent laser beam L2.

  The laser beam from the LD 14 is reflected by the mirror M4 to become a divergent laser beam L4.

  In this way, two divergent laser beams L2 and L4 are emitted from the holding housing H2.

  The holding housings H1 and H2 are overlapped as shown in FIG. 5C, and the divergent laser beams L1 to L5 emitted from these are shown in FIG. 1A when viewed from the upper side of FIG. 5C. In such a manner, it is arranged in such a “opening angle: θ = 50 degrees fan shape”.

  As shown in the figure, the divergent laser beams L1, L3, and L5 and the divergent laser beams L2 and L4 are not in the same plane, but the plane on which they are arranged is close to the vertical direction in FIG. doing.

  Effective projection distance: Since the DLM is as long as 200 m, even if the divergent laser beams L1, L3, L5, L2, and L4 are not in the same plane, the effective projection distance is a state in which the detection target near the DLM is irradiated. Then, these irradiation areas substantially overlap and become the same area.

  That is, the laser beam projection unit shown in FIG. 5 emits five divergent laser beams L1 to L5 in a fan shape with an opening angle of θ (= 50 degrees) without being separated from each other.

  Then, five LDs 11 to 15, five coupling lenses CL 1 to CL 5 that convert the laser beams from the five laser light sources into five divergent laser beams, and five coupling lenses 5. Beam combining means M1 to M4, H1, and H2 for arranging the divergent laser light beams L1 to L5 in a fan shape with an opening angle of θ are provided.

  Also in the second embodiment, the coupling lenses CL1 to CL5 are “a light beam conversion optical system in which laser light beams from five laser light sources are converted into five divergent laser light beams”.

On the other hand, as the laser light receiving unit, the one as shown in FIG. 3 was configured.
The light receiving element array 306 of the laser light receiving unit 33 is configured using an APD as each of the independent light receiving elements PD1 to PD5.
The LDs 11 to 15 repeated “simultaneous blinking of 2 μsec cycle” of 1 μsec on and 1 μsec off several times.

  As described above, even if the object to be detected is located at a position of 200 m, the time required to pass 400 m is 1.33 μsec (<2 μsec), and returns to the same blinking cycle (2 μsec) of LD11 to LD15. Detection of the laser beam is sufficiently possible.

  Each APD was independently controlled, and as described above, the detection target (vehicle, obstacle, etc.) 200 m ahead could be detected well.

  Regarding the direction of the test object, the divergence angle of each divergent laser beam is the limit of detection, but there is no practical problem as a vehicle-mounted laser radar.

  A sufficiently well-measured value was obtained for the distance of the test object.

  In the first and second embodiments described above, the divergence angles of the plurality of divergent laser beams L1 to L5 arranged in a fan shape having an opening angle: θ are the same, but the present invention is not limited to this.

  The divergence angle of the divergent laser beam emitted from each laser light source of the laser beam projection unit can be varied according to the purpose of use of the laser radar device.

  For example, when the laser radar device of the present invention is used for in-vehicle use, out of the n divergent laser beams, the beam at the center is required to have a small divergence angle so that “the vehicle ahead can be quickly confirmed”. It is done.

  However, near a vehicle equipped with a laser radar device, pedestrians, oncoming vehicles, and the like appear to be relatively large, so a divergent laser beam having a large divergence angle in the vertical direction is required.

  An example in such a case is given as Example 3.

"Example 3"
As Example 3, a laser beam projection unit as shown in FIGS. 6 and 7 was used, and a laser beam receiving unit as shown in FIG. 2 was used. In addition, in order to avoid complication, the thing which does not seem to have a possibility of confusion is attached | subjected the same code | symbol as in FIG. 1, FIG.

  The laser radar device according to the third embodiment is for vehicle use.

  Referring to FIG. 6, the five divergent laser beams L1 to L5 radiated from the laser beam projection unit 10 radiate upward about several degrees in parallel with the ground GR as shown in FIG. 6B. Is done.

  The “divergence angles in the direction perpendicular to the ground GR” of these divergent laser beams L1 to L5 are not uniform, and the divergent angle of the central divergent laser beam L3 (the light beam traveling forward) is the smallest.

  The divergence angles of the divergent laser light beams L2 and L4 adjacent to the divergent laser light beam L3 and the divergent laser light beams L1 and L5 outside the divergent laser light beams L3 and L5 gradually increase.

  The effective projection distances of the divergent laser beams L1, L2, L4, and L5 whose divergence angles in the direction orthogonal to the ground GR are larger than the effective projection distance of the divergent laser beam L1.

  In FIG. 6A, the “length in the projection direction” of the divergent laser light beam is smaller as the light beam in the peripheral portion represents this situation.

  FIG. 7 shows the configuration of the laser beam projection unit 10 used in the laser radar apparatus of the third embodiment, following FIG. In order to avoid confusion, the same symbols as in FIG.

  The difference from the laser beam projection unit in FIG. 4 is that cylinder lenses CY1, CY2, CY4, and CY5 are arranged.

  The cylinder lenses CY1 and CY5 are held by the holding housing H1, and the cylinder lenses CY2 and CY4 are held by the holding housing H2.

  All of the four cylinder lenses CY1, CY2, CY4, and CY5 have “positive refractive power” in a direction orthogonal to the drawings of FIGS. 7A and 7B.

  The cylinder lenses CY1 and CY5 have the same optical characteristics, and the cylinder lenses CY2 and CY4 also have the same optical characteristics.

  As shown in FIG. 7A, the cylinder lens CY1 is disposed between the coupling lens CL1 and the mirror M1.

  The cylinder lens CY1 further focuses the laser light emitted from the LD 11 and converted into a focused light beam by the coupling lens CL1 in a direction orthogonal to the drawing.

  Thereby, the divergence angle of the divergent laser beam L1 in the direction orthogonal to the drawing is larger than the divergence angle in the plane parallel to the drawing.

  Similarly, the cylinder lens CY5 disposed between the coupling lens CL5 and the mirror M2 further focuses the laser light emitted from the LD 15 and converted into a focused light beam by the coupling lens CL5 in a direction orthogonal to the drawing.

  Thereby, the divergence angle of the divergent laser beam L5 in the direction orthogonal to the drawing is larger than the divergence angle in the plane parallel to the drawing.

  The cylinder lens CY2 shown in FIG. 7B is disposed between the coupling lens CL2 and the mirror M3.

  The cylinder lens CY2 further focuses the laser light emitted from the LD 12 and converted into a focused light beam by the coupling lens CL2 in a direction orthogonal to the drawing.

  Thereby, the divergence angle of the divergent laser beam L2 in the direction orthogonal to the drawing is larger than the divergence angle in the plane parallel to the drawing.

  Similarly, the cylinder lens CY4 disposed between the coupling lens CL4 and the mirror M4 further focuses the laser light emitted from the LD 14 and converted into a focused beam by the coupling lens CL4 in a direction orthogonal to the drawing.

  As a result, the divergence angle in the direction orthogonal to the drawing of the divergent laser beam L4 is larger than the divergence angle in a plane parallel to the drawing.

  In the example in the description, the cylinder lenses CY1, CY2, CY4, and CY5 have “the same positive refractive power” in the direction orthogonal to the drawing positions in FIGS.

  Each of these cylinder lenses CY1, CY2, CY4, and CY5 is a plano-convex shape having a convex cylinder surface on the side facing the light source and a flat surface on the opposite side.

  The distance between the cylinder lens CY1 and the coupling lens CL1 is equal to the distance between the cylinder lens CY5 and the coupling lens CL5. This distance is assumed to be “DA”.

  The distance between the cylinder lens CY2 and the coupling lens CL2 is equal to the distance between the cylinder lens CY4 and the coupling lens CL4. This distance is assumed to be “DB”.

  As shown in the figure, the distance: DA is larger than the distance: DB.

  Thereby, in the direction orthogonal to the drawing, the divergent laser beams L1 and L5 are closer to the light source than the divergent laser beams L2 and L4.

  Accordingly, the divergent angles in the direction orthogonal to the drawing are larger for the divergent laser beams L1 and L5 than for the divergent laser beams L2 and L4.

  The holding housings H1 and H2 are overlapped as shown in FIG. 7C, and the divergent laser beams L1 to L5 emitted from these are shown in FIG. 6A when viewed from the upper side of FIG. 7C. In this way, they are arranged in a fan shape having an opening angle: θ = 50 degrees.

  As shown in the figure, the divergent laser beams L1, L3, and L5 and the divergent laser beams L2 and L4 are not in the same plane, but the surface on which they are arranged is close to the vertical direction in FIG. doing.

  Effective projection distance: Since the DLM is as long as 200 m, even if the divergent laser beams L1, L3, L5, L2, and L4 are not in the same plane, the effective projection distance is a state in which the detection target near the DLM is irradiated. Then, these irradiation areas substantially overlap and become the same area.

  FIG. 6B illustrates the state of the divergent laser light beams L1 to L3 emitted from the laser light beam projection unit 10 when viewed from a direction orthogonal to the projection direction and parallel to the ground GR. .

  FIG. 6C is a diagram illustratively showing a state in which five divergent laser light beams L1 to L5 are viewed from the projection direction side.

  As described above, in FIG. 6B, the divergent laser light beams L1 to L5 are emitted “approximately parallel to the ground GR and upward by several degrees”, but the radiation direction of the divergent laser light beam (projection direction) ) Is not limited to this.

  In the same way as described above with reference to FIG. 1C, the projection direction of the divergent laser light beam in FIG. 6 is “essentially parallel to the ground GR”, and the specific use situation of the laser radar device An appropriate direction may be selected according to the situation.

  The “laser beam projection unit” shown in FIG. 7 emits five divergent laser beams L1 to L5 in a fan shape with an opening angle of θ (= 50 degrees) so as not to be separated from each other.

  As shown in FIGS. 7A and 7B, no cylinder lens is arranged on the optical path of the laser light emitted from the LD 13, and therefore the divergence angle of the divergent laser beam L3 is as shown in FIG. Is the same.

  In this laser beam projection unit, the coupling lenses CL1, Cl2, CL4, and CL5, and the cylinder lenses CY1, CY2, CY4, and CY5 combined therewith, together with the coupling lens CL3, “receive the laser beams from the five laser light sources. 5 "is a light beam conversion optical system that uses five divergent laser light beams.

  Also. M1 to M4 and the holding housings H1 and H2 constitute beam combining means for arranging the five divergent laser beams L1 to L5 in a fan shape having an opening angle of θ.

  As the laser light receiving unit, the one shown in FIG.

  In the same manner as in Example 1, the detection target (vehicle, obstacle, etc.) located 200 m ahead of the laser radar device could be detected with good azimuth and distance.

  In addition, detection objects (pedestrians, oncoming vehicles, etc.) in the vicinity of the device could be detected well in both direction and distance.

  In Example 3, the divergence angles in the direction orthogonal to the fan-shaped surfaces of the divergent laser beams L1 to L2 are varied, but the present invention is not limited thereto.

  For example, an object to be detected 600 m ahead can be detected by setting the divergence angle of the divergent laser beam L3 to 5 degrees, and the object to be detected 200 m ahead by setting the divergence angles of the diverging laser beams L2 and L4 in the vertical direction to 10 degrees An object can be detected, and the divergence angle in the vertical direction of the divergent laser beams L1 and L5 can be set to 20 degrees so that a test object 100 m ahead can be detected.

  When the laser radar device of the present invention is used for in-vehicle use, a plurality of laser radar devices can be arranged at the center and both sides of the area.

  Further, by combining a coupling lens CL1, CL2, CL4, CL5 of the laser beam projection unit shown in FIG. 5 with a cylinder lens having “negative refractive power” in a direction orthogonal to the ground, FIG. The same divergent laser beams L1 to L5 can be generated.

  Further, the divergence angle of the divergent laser light beam can be varied in directions orthogonal to each other in a plane orthogonal to the light beam traveling direction. For this purpose, in addition to the cylinder lens, a toroidal lens is used. And other “anamorphic lenses” can be used.

  By combining such an anamorphic lens with a coupling lens, it is possible to increase the degree of freedom for configuring the light beam conversion optical system.

Hereinafter, the system of the laser radar apparatus will be briefly described.
FIG. 8 is a system diagram of the laser radar device.
In FIG. 8, reference numeral 10 denotes the laser beam projection unit described with reference to FIGS. 1 and 6, and specifically, those shown in FIGS. 4, 5, and 7 can be used.

  Reference numeral 30 denotes a “laser light receiving portion”, which receives the return laser beam BKL.

  As the laser light receiving unit 30, a combination of the azimuth detecting light receiving unit 310 and the distance measuring light receiving unit 320 shown in FIG. 2 or the laser light receiving unit 330 shown in FIG. 3 is used.

  The control calculation unit 61 includes a microcomputer, a CPU, and interfaces, and controls the laser beam projection unit 10 and the laser light receiving unit 30.

  That is, the control calculation unit 61 controls, on the one hand, blinking of each laser light source of the laser beam projection unit 10, and on the other hand, the optical position sensor, the light receiving element of the laser light receiving unit 30, and the individual light receiving elements of the light receiving element array. Control to convert the “light-receiving state of the return laser beam” into a signal.

  Then, based on the light reception information signaled in this way, the orientation of the test object reflecting the return laser beam and the distance to the test object are specified and output.

  This output information is sent to the display 62 constituting the “display unit” and displayed on the display 62.

  As described above, according to the present invention, the following laser radar device can be realized.

[1]
A laser beam projection unit (10) that radiates n (≧ 2) divergent laser beams (L1 to L5) in a fan shape with an opening angle: θ so as not to be separated from each other, and radiation from the laser beam projection unit The laser beam receiving unit (310, 320, 330) that receives the return laser beam (BKL) reflected by the object so as to specify the direction of the object, and controls the laser beam projection unit and the laser beam receiving unit. Then, the control calculation unit (61) for specifying and outputting the direction of the object reflecting the return laser beam and the distance to the object based on the light reception information of the laser beam receiving unit, and the output of the control calculation unit And a display unit (62) for displaying.

[2]
In the laser radar device according to [1], the laser beam projection unit 10 includes n (≧ 2) laser light sources (LD11 to LD15) and n light beams from the n laser light sources. M (1 ≦ m ≦ n) light beam conversion optical systems (CL1 to CL5, CY1, CY2, CY4, CY5) as laser light beams and n divergent laser light beams by m light beam conversion optical systems, Beam combining means (M1 to M4, H1, H2) arranged in an opening angle: θ fan shape,
The laser light receiving unit includes a condensing unit that condenses the return laser beam (BKL), and a light receiving unit that receives the return laser beam condensed by the condensing unit. A laser radar device capable of specifying the direction of laser light.

[3]
In the laser radar device according to [2], m (1 ≦ m ≦ n) light beam conversion optical systems (CL1 to CL5, CY1, CY2, CY4, CY5) have a divergence angle in a direction orthogonal to the fan-shaped array. A laser radar device that forms divergent laser beams with different values.

[4]
In the laser radar device according to [2] or [3], the light receiving unit has an azimuth detecting light receiving unit (310) and a distance measuring light receiving unit (320), and the azimuth detecting light receiving unit (310). Includes an imaging lens (301) and an optical position sensor (302), and the distance measuring light receiving section (320) includes a condenser lens (303) and a light receiving element (304). .

[5]
In the laser radar device according to [2] or [3], the light receiving means (330) includes an imaging lens (305) and a light receiving element array (306), and the light receiving element array (306) includes n pieces. A laser radar device which is an array arrangement of n or more independent light receiving elements (PD1 to PD5) according to the divergent laser beam.

[6]
The laser radar device according to any one of [2] to [5], wherein the control calculation unit (61) causes the n laser light sources (LD11 to LD15) to blink sequentially in time series.

[7]
[5] The laser radar device according to [5], wherein the control calculation unit (61) causes the n laser light sources (LD11 to LD15) to blink simultaneously.

The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the specific embodiments described above, and the invention described in the claims unless otherwise specified in the above description. Various modifications and changes are possible within the scope of the above.
For example, as the “laser beam projection unit” in the first embodiment, the one in FIG. 5 or 6 can be used instead of the one in FIG. 4, and conversely, the laser beam projection unit in the second embodiment is shown in FIG. Or the one shown in FIG. 6 can be used.

  In addition, in the laser beam projection unit, the divergent laser beam from the LD is changed to a “divergent laser beam having a predetermined divergence angle”. The predetermined divergence angle can be realized while reflecting the light.

  Alternatively, the divergence angle can be adjusted by using the reflecting surfaces of the mirrors M1 to M4 in FIGS. 4 and 5 as concave surfaces or convex surfaces.

  When the laser radar device of the present invention is used for in-vehicle use, a plurality of laser radar devices can be arranged at the center and both sides of the area.

  The effects described in the embodiments of the present invention are merely a list of suitable effects resulting from the invention, and the effects of the present invention are not limited to those described in the embodiments.

10 Laser beam projection unit
L1, L2, L3, L4, L5 Divergent laser beam
310 Photodetector for direction detection
320 Light receiver for distance measurement
301 Imaging lens
303 condenser lens
330 Laser beam detector
305 Imaging lens
306 Light receiving element array

US Pat. No. 5,477,461

Claims (7)

a laser beam projection unit that radiates n (≧ 2) divergent laser beams in a fan shape with an opening angle: θ so as not to be separated from each other;
A laser beam receiving unit that receives the return laser beam emitted from the laser beam projection unit and reflected by the object so that the orientation of the object can be specified;
A control calculation unit that controls the laser beam projection unit and the laser beam receiving unit, and specifies and outputs the direction of the object reflecting the return laser beam and the distance to the object based on the light reception information of the laser beam receiving unit When,
A laser radar device comprising: a display unit configured to display an output of the control calculation unit. The laser radar device according to claim 1, wherein
The laser beam projection unit
n (≧ 2) laser light sources;
M (1 ≦ m ≦ n) light beam conversion optical systems in which the laser light beams from the n laser light sources are n divergent laser light beams,
beam combining means for arranging n divergent laser light beams by m light beam conversion optical systems in a fan shape with an opening angle of θ,
The laser beam receiver
Condensing means for condensing the return laser beam;
A light receiving means for receiving the return laser beam condensed by the light collecting means,
The laser radar device, wherein the light receiving means can identify the direction of the return laser beam. The laser radar device according to claim 2, wherein
A laser radar apparatus in which m (1 ≦ m ≦ n) light beam conversion optical systems form divergent laser beams having different divergence angles in a direction orthogonal to the fan-shaped array. The laser radar device according to claim 2 or 3,
The light receiving means has an azimuth detecting light receiving portion and a distance measuring light receiving portion separately,
The azimuth detecting light receiving unit includes an imaging lens and an optical position sensor,
The distance measuring light receiving unit includes a condensing lens and a light receiving element. The laser radar device according to claim 2, 3 or 4,
The light receiving means has an imaging lens and a light receiving element array,
The said light receiving element array is a laser radar apparatus which is an array arrangement | sequence of n or more independent light receiving elements according to n divergent laser beams. In the laser radar device according to any one of claims 2 to 5,
A laser radar device in which a control calculation unit sequentially flashes n laser light sources in time series. The laser radar device according to claim 5, wherein
A laser radar device in which a control arithmetic unit blinks n laser light sources simultaneously.

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