JP2017049097A - Laser radar device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser radar device with which it is possible to detect the dirt of a housing window and suppress the occurrence of a time in which an object on the outside of the device becomes non-detectable due to the dirt of the housing window.SOLUTION: Provided is a laser radar device 1 comprising a laser diode 10 for projecting an irradiation light L0, a housing window 82 which the irradiation light L0 and an external reflectance L1 generated as the irradiation light L0 is reflected by an external object pass through, and a first photodiode 20 for receiving the external reflectance L1, the laser radar device further including a second photodiode 45, separately from the first photodiode 20, at a position where it is possible to receive, with distinguishable strength of received light, a dirt diffuse reflectance L3 which, when an impermeable dirt 84 is stuck to a portion of the housing window 82 which the irradiation light L0 passes through, is generated as the irradiation light L0 is reflected by the dirt 84, and a regular diffuse reflectance L2 which, when there is no dirt sticking to the portion of the housing window 82 which the irradiation light L0 passes through, is generated when the irradiation light L0 passes through the housing window 82.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a laser radar device, and more particularly to a technique for detecting dirt adhering to a housing window provided in the laser radar device.

  The laser radar device irradiates the outside while scanning with laser light, and receives the reflected light generated by reflecting the irradiated laser light with an external object. Hereinafter, the laser light emitted by the laser radar apparatus may be referred to as irradiation light in order to distinguish it from the reflected light that is generated when the laser light is reflected by an object. The laser radar device calculates the distance to the object from the time from the irradiation light irradiation until the reflected light is received and the speed of light.

  The entire laser radar device is covered with a housing, and a light transmissive housing window that protects internal components while allowing irradiation light and reflected light to pass therethrough is provided in a portion of the housing. If impermeable dirt adheres to the housing window, it becomes impossible to irradiate the irradiation light to the outside of the apparatus, and the distance to the object cannot be calculated.

  Therefore, a technique for determining whether or not dirt is attached to the housing window is known. For example, in Patent Document 1, when the measurement time is shorter than a predetermined measurement time and is equal to or higher than a predetermined light reception intensity, it is determined that dirt is attached to the housing window.

Japanese Patent Laying-Open No. 2005-10094

  In Patent Document 1, it is determined whether or not dirt is attached to the housing window using a light receiving sensor that receives externally reflected light that is reflected by an object outside the apparatus. Dirt adheres to the housing window, and the reflected light generated by reflection from the dirt is less attenuated because the optical path length is short. Therefore, since the light reception intensity is high, the light reception sensor may be saturated. The case where the light receiving sensor is saturated is not limited to the case where dirt is attached to the entire range through which the irradiation light from the housing window passes. Even when dirt is attached to a part of the range through which the irradiation light passes, there is a possibility that the light receiving sensor is saturated with the reflected light due to the dirt.

  Therefore, in the technique of Patent Document 1, dirt is partially attached to the range through which the irradiation light passes in the housing window, and even if a part of the irradiation light is irradiated to the outside of the apparatus, the irradiation light Since the remaining part of the light is reflected by the dirt adhering to the housing window and received by the light receiving sensor, there is a possibility that a time during which reflected light from an external object cannot be detected may occur.

  The present invention has been made based on this situation, and the object of the present invention is to detect the dirt on the casing window and not to detect an object outside the apparatus due to the dirt on the casing window. An object of the present invention is to provide a laser radar device that can suppress the occurrence of time.

  The above object is achieved by a combination of the features described in the independent claims, and the subclaims define further advantageous embodiments of the invention. Reference numerals in parentheses described in the claims indicate a correspondence relationship with specific means described in the embodiments described later as one aspect, and do not limit the technical scope of the present invention. .

The invention according to claim 1 for achieving the above object includes a light projecting unit (10) for generating and projecting laser light,
A housing window (82) through which laser light projected by the light projecting unit and external reflected light generated by reflecting the laser light on an external object pass;
A light receiving sensor (20) for externally reflected light that receives externally reflected light;
A laser radar device (1, 100, 200, 300, 400) comprising:
When the opaque light is attached to the part of the housing window where the laser light passes, the laser light of the housing window passes through the diffuse diffuse reflection light that is reflected when the laser light is reflected by the dirt. The external reflected light receiving sensor at a position where it can be received with a light receiving intensity distinguishable from normal diffuse reflected light that is reflected light when the laser light passes through the housing window when no dirt is attached Is provided with another light receiving sensor (45) for detecting dirt.

  The dirt diffuse reflection light is generated by Lambertian diffuse reflection by impermeable dirt adhering to the housing window. On the other hand, normal diffuse reflected light is reflected light that has been diffusely reflected with an intensity distribution similar to the normal distribution. Therefore, if the dirt detection light receiving sensor is disposed at a position where the reflected light traveling in the direction where the angle with respect to the maximum reflection direction, which is the direction in which the intensity of the diffuse reflected light is the strongest, is large, is detected, Diffuse reflected light can be received with a received light intensity that is distinguishable from normal diffuse reflected light. Therefore, it is possible to determine whether or not impermeable dirt is attached to the housing window from the detection value of the dirt detection light receiving sensor.

  The dirt detection light receiving sensor is a light receiving sensor provided in addition to the external reflected light receiving sensor. Therefore, it is not necessary to detect the contamination of the housing window using the external reflected light receiving sensor. Accordingly, it is possible to reduce the gain of the external reflected light light receiving sensor from when the laser light is projected until the dirt diffuse reflected light reaches the external reflected light light receiving sensor. As a result, it is possible to prevent the detection value of the light receiving sensor for external reflected light from being saturated by the dirt diffuse reflected light, thereby preventing the occurrence of a time during which an object outside the apparatus cannot be detected due to dirt on the housing window. it can.

According to the second aspect of the present invention, the rotating mirror (50) reflects the laser light projected by the light projecting unit in the direction of the housing window while rotating and reflects the externally reflected light in the incident direction of the laser light. With
The dirt detection light receiving sensor is characterized in that the rotating mirror is arranged in a direction to reflect the external reflection light.

  According to the present invention, a part of the dirt diffused reflection light generated by the reflection of the laser beam by the impermeable dirt attached to the housing window is reflected by the rotating mirror, so that the external reflected light is reflected by the rotating mirror. As in the case of reflection, the light is reflected in the incident direction of the laser beam, that is, in a certain direction, regardless of the angle at which the dirt is attached.

  Therefore, it is possible to detect dirt diffused reflected light generated at a plurality of locations of the casing window by the same dirt detection light receiving sensor. Therefore, it is not necessary to prepare a dirt detection sensor for each angle at which it is necessary to detect impermeable dirt in the housing window, so that the number of dirt detection sensors can be reduced.

The invention according to claim 3 has a through-hole (42) through which the laser light projected by the light projecting unit passes and reaches the rotating mirror between the light projecting unit and the rotating mirror. It has a reflecting surface (41), and includes a perforated mirror (40) that reflects externally reflected light reflected by the rotating mirror in the direction of the light receiving sensor for externally reflected light,
The housing window is usually inclined so that the maximum intensity direction of diffuse reflected light is in the direction of the perforated mirror rather than the rotating mirror,
The dirt detection light receiving sensor is arranged on the optical path of dirt diffused reflected light on the light projecting unit side with respect to the perforated mirror.

  The laser beam reflected by the rotating mirror and directed to the housing window is somewhat reflected by the housing window even if the housing window is not dirty. That is, normally diffuse reflected light is generated. Normally, diffused reflected light returns to the rotating mirror, is reflected by the perforated mirror, and is detected by the light receiving sensor for externally reflected light. For this reason, the casing window of the laser radar device provided with the perforated mirror is inclined so that normally diffuse reflected light does not face the direction of the rotating mirror. Similar to the inclination of a general casing window, in the invention according to claim 3, the inclination of the casing window is an inclination in which the direction of the maximum intensity of diffuse reflected light is usually a perforated mirror direction rather than a rotating mirror. . For this reason, if the dirt detection light-receiving sensor is located on the rotating mirror side of the perforated mirror, the dirt detection light-receiving sensor may receive normal diffuse reflected light.

  However, in the invention according to claim 3, the dirt detection light receiving sensor is arranged closer to the light projecting portion than the perforated mirror. Accordingly, since the normal diffuse reflection light is blocked by the perforated mirror, it is possible to prevent the dirt detection light receiving sensor from receiving the normal diffuse reflection light.

  On the other hand, since the dirt diffuse reflected light undergoes Lambert diffuse reflection, a part thereof is reflected by the rotating mirror and passes through the through hole of the perforated mirror. Therefore, the dirt diffuse reflected light can be detected by the dirt detecting light receiving sensor disposed on the optical path of the dirt diffuse reflected light on the light projecting portion side of the perforated mirror.

The invention according to claim 4 includes a diffuse reflection member (44) disposed on the optical path of the dirt diffuse reflected light and having a surface shape that further diffuses and reflects the dirt diffuse reflected light.
The dirt detection light receiving sensor is arranged at a position facing the diffuse reflection member.

  According to the fourth aspect of the present invention, the dirt diffuse reflection light is diffusely reflected by the diffuse reflection member. Therefore, if the dirt detection light receiving sensor is disposed at a position facing the diffuse reflection member, the dirt diffuse reflection light is detected. Can be received. This eliminates the need for detailed calculations to determine the position of the dirt detection sensor, facilitating the design, and allows the dirt diffuse reflected light to be received even if the dirt detection sensor mounting position is slightly shifted. Assembling is also easy.

In the invention which concerns on Claim 5, the housing | casing window is formed in a part of the perimeter of a laser radar apparatus,
The rotating mirror is usually located in a direction that is not the direction of maximum intensity of diffuse reflected light and reflects dirt diffuse reflected light,
The light receiving sensor for detecting dirt has a light receiving surface facing in a direction in which the housing window is not formed,
A reflection member (44) is provided on the optical path of the dirt diffuse reflected light reflected by the rotating mirror and reflects the dirt diffuse reflected light toward the dirt detection light receiving sensor.

  According to this invention, the light receiving surface of the dirt detection light receiving sensor faces the direction in which the housing window is not formed. Therefore, the normal diffuse reflection light reflected by the housing window is not directly received by the dirt detection sensor.

  Further, the rotating mirror is usually arranged in a direction that is not the direction of the maximum intensity of the diffuse reflected light. Normally diffused reflected light is diffusely reflected with an intensity distribution similar to the normal distribution, so if the rotating mirror is placed in a direction that is not in the direction of the maximum intensity of the normally diffused reflected light, it is reflected by the rotating mirror. The light intensity is low. Therefore, the normal diffuse reflected light is also prevented from being reflected by the rotating mirror and received by the dirt detection light receiving sensor.

  On the other hand, since the dirt diffuse reflected light is reflected light that has been subjected to Lambert diffuse reflection, a part of the dirt diffuse reflected light is reflected by the rotating mirror while maintaining a high intensity. In the present invention, since the reflecting member for reflecting the dirt diffuse reflected light reflected by the rotating mirror is provided in the direction of the dirt detecting light receiving sensor, the dirt diffuse reflected light can be detected by the dirt detecting light receiving sensor.

It is a schematic sectional drawing of the laser radar apparatus 1 of 1st Embodiment. It is a figure which shows arrangement | positioning and shape of the diffuse reflection member 44 of FIG. It is a figure which shows a part of the direction in which the stain | pollution | contamination diffuse reflection light L3 arises with the stain | pollution | contamination 84 adhering to the housing | casing window 82. It is a block diagram of the laser radar apparatus 100 of 2nd Embodiment. It is a block diagram of the laser radar apparatus 200 of 3rd Embodiment. It is a block diagram of the laser radar apparatus 300 of 4th Embodiment. It is a block diagram of the laser radar apparatus 400 of 5th Embodiment.

<First Embodiment>
Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, the laser radar device 1 of the first embodiment receives a laser diode 10 that is a light projecting unit and reflected light (hereinafter referred to as external reflected light) L1 from an object outside the device. This device includes a diode 20 and detects the distance and direction to an object outside the device. The laser radar device 1 is installed outdoors and detects an object that moves within the monitoring area of the laser radar device 1.

  In FIG. 1, a laser diode 10 is supplied with a pulse current from a drive circuit and projects pulsed laser light (hereinafter referred to as irradiation light L0). The first photodiode 20 corresponds to an example of a light receiving sensor for externally reflected light, and detects the externally reflected light L1 generated by the irradiation light L0 being reflected by an object outside the apparatus and converts it into an electrical signal.

  A collimating lens 30 and a perforated mirror 40 are provided on the optical axis of the laser diode 10. The collimating lens 30 converts the irradiation light L0 projected by the laser diode 10 into parallel light.

  The perforated mirror 40 has a flat plate shape and is disposed on the optical axis of the laser diode 10 at an angle with respect to the optical axis. The lower surface of the perforated mirror 40, that is, the surface on the rotating mirror 50 side is a reflecting surface 41, and penetrates the center of the perforated mirror 40 in the vertical direction, that is, in the optical axis direction of the laser diode 10. A through-hole 42 is formed. The perforated mirror 40 is arranged so that the through hole 42 is positioned on the optical axis of the laser diode 10.

  A diffuse reflection member 44 and a second photodiode 45 are disposed on a surface 43 (hereinafter referred to as a light projecting portion side surface) 43 of the perforated mirror 40 on the laser diode 10 side. As shown in FIG. 2, the diffuse reflection member 44 protrudes from the light projecting portion side surface 43 of the perforated mirror 40 and is disposed around the through hole 42 so as to surround at least a half circumference of the through hole 42. ing. The direction in which the diffuse reflection member 44 is disposed with respect to the through hole 42 is opposite to the housing window 82 with respect to the through hole 42. In other words, the direction of the through hole 42 that is not surrounded by the diffuse reflection member 44 is the direction of the housing window 82. The diffuse reflection member 44 is made of paper in this embodiment. Since it is made of paper, the surface is not a mirror surface. Since the surface shape is not a mirror surface, it diffusely reflects when light strikes the diffuse reflection member 44.

  The second photodiode 45 is disposed on the front side of the laser radar device 1 with respect to the diffuse reflection member 44. The direction of the second photodiode 45 is the direction in which the light receiving surface faces the direction of the diffuse reflecting member 44, that is, the direction in which the light receiving surface faces the diffuse reflecting member 44. Therefore, the direction of the light receiving surface of the second photodiode 45 in the horizontal plane is the direction of the back surface 81 of the housing 80, that is, the direction in which the housing window 82 is not formed. The second photodiode 45 is an example of a dirt detection light receiving sensor.

  A rotating mirror 50 is provided on the optical axis of the irradiation light L0 passing through the perforated mirror 40. The rotating mirror 50 is disposed so as to be rotatable about a central axis extending in the optical axis direction of the laser diode 10, and deflects the irradiation light L0 by a concave mirror 51 whose focal position is set on the central axis. The irradiation light L0 is irradiated toward the outside of the apparatus. The concave mirror 51 deflects the external reflected light L1 in the direction of the perforated mirror 40.

  Further, a motor 60 that rotates the rotating mirror 50 is provided. The motor 60 rotates the rotating shaft 61 to rotate the rotating mirror 50 connected to the rotating shaft 61. The rotating shaft 61 is a rotating shaft of the motor 60, and the rotating mirror 50 is rotated by the rotation of the rotating shaft 61.

  The rotation angle position sensor 62 detects the rotation angle position of the rotation shaft 61 (that is, the rotation angle position of the concave mirror 51). As the rotation angle position sensor 62, various types of sensors can be used as long as they can detect the rotation angle position of the rotation shaft 61, such as a rotary encoder.

  The circuit unit 70 acquires the detection value of the driving circuit that drives the laser diode 10, the distance calculation circuit that calculates the distance to the object based on the detection signal detected by the first photodiode 20, and the rotation angle position sensor 62. A motor drive circuit that rotates the motor 60 at a predetermined rotation speed while determining the rotation position and rotation speed of the rotary mirror 50 is provided. Further, a stain determination circuit for determining whether or not impermeable stain (hereinafter simply referred to as stain) 84 is attached to the housing window 82 based on a signal detected by the second photodiode 45 is also provided.

  These configurations are accommodated in the internal space of the apparatus formed by the casing 80 and the casing window 82. The housing 80 has a box shape in which a portion to which the housing window 82 is attached is opened. The casing window 82 is made of a light transmissive member and is attached to the casing 80. The range around the horizontal plane to which the housing window 82 is attached is a scan angle range or an angle range larger than the scan angle range with the front direction of the laser radar device 1 as the center. The scanning angle range is, for example, 190 degrees. The front direction of the laser radar device 1 is a direction from the inside of the laser radar device 1 toward the housing window 82 in a vertical section that bisects the housing window 82.

  The casing window 82 is a plate-like body, and the horizontal sectional shape is partially curved in an arc shape. Further, the housing window 82 is inclined so that the distance to the rotating shaft 61 in the plane orthogonal to the rotating shaft 61 becomes longer toward the upper side.

  The reason why the housing window 82 is inclined in this way is that the reflected light partially reflected by the housing window 82 is not detected by the first photodiode 20 when the irradiation light L0 passes through the housing window 82. It is for doing so.

  Hereinafter, the dirt 84 does not adhere to the portion of the casing window 82 through which the irradiation light L0 passes, and a part of the irradiation light L0 is reflected by the casing window 82 when passing through the casing window 82. The reflected light thus generated is referred to as normal diffuse reflected light L2.

[Explanation of optical path]
The irradiation light L0 is periodically projected from the laser diode 10, converted into parallel light by the collimating lens 30, passes through the through hole 42 of the perforated mirror 40, is reflected by the rotary mirror 50, and is reflected by the housing window. Irradiates outside the apparatus through 82. Further, since the rotating mirror 50 rotates at a predetermined speed, the direction in which the irradiation light L0 is irradiated changes at a constant angular velocity.

  When the irradiation light L0 is reflected by an object outside the apparatus, external reflection light L1 is generated. The externally reflected light L1 passes through the housing window 82 and enters the apparatus, is reflected by the concave mirror 51 of the rotating mirror 50, and is deflected in the direction of the reflecting surface 41 of the perforated mirror 40. Further, the light is reflected by the reflecting surface 41 and enters the first photodiode 20.

  When the irradiation light L0 passes through the unstained casing window 82, a part of the irradiation light L0 is reflected by the casing window 82 to generate normal diffuse reflection light L2. Normally, the diffusely reflected light L2 is reflected at the maximum intensity in the direction shown in FIG. 1 according to the law of reflection. Hereinafter, the direction shown in FIG. The inclination of the casing window 82 is set so that the maximum reflection direction does not become the direction toward the rotary mirror 50.

  However, the normal diffuse reflected light L2 is also generated in directions other than the maximum reflection direction. The normal diffuse reflected light L2 has a shape similar to the normal distribution in the relationship between the angle and the intensity with respect to the maximum reflection direction with the maximum reflection direction as the center. Since the shape is similar to the normal distribution, a part of the normal diffuse reflected light L2 is reflected in the direction of the rotating mirror 50, but the intensity of the normal diffuse reflected light L2 reflected by the rotating mirror 50 is weak. Therefore, the normal diffuse reflected light L2 is not detected by the first photodiode 20 or the second photodiode 45, or is detected with a sufficiently low intensity even if it is detected.

  On the other hand, if the dirt 84 adheres to the portion of the housing window 82 irradiated with the irradiation light L0, the irradiation light L0 is reflected by the dirt 84. The reflected light generated at this time is referred to as dirt diffuse reflected light L3.

  The dirt diffuse reflected light L3 undergoes Lambert diffuse reflection. The reflection center of the dirt diffuse reflected light L3 is the same as that of the normal diffuse reflected light L2, but because of Lambert diffuse reflection, the dirt diffuse reflected light L3 in a direction having a large angle with respect to the maximum reflection direction has a relatively strong intensity.

  Therefore, the dirt diffuse reflected light L3 is generated with strong intensity in various reflection directions. As a result, as shown in FIG. 3, a part of the dirt diffuse reflection light L3 is reflected by the concave mirror 51 and passes through the through hole 42 of the perforated mirror 40 at various positions of the diffuse reflection member 44. Reflected. Therefore, the diffuse reflection member 44 is disposed on the optical path of the dirt diffuse reflection light L3. In FIG. 3, the optical path is mainly shown for the dirt diffuse reflected light L3 passing through the through hole 42.

  Further, since the diffuse reflection member 44 is made of paper, the dirt diffuse reflection light L3 is diffusely reflected by the diffuse reflection member 44. Dirt diffuse reflection light L3 diffusely reflected by the diffuse reflection member 44 is detected by the second photodiode 45.

  As described above, the normal diffusion reflected light L2 is not detected by the second photodiode 45 or is detected with a sufficiently low intensity even if it is detected. It is arranged at a position where L2 and dirt diffuse reflected light L3 can be received with a received light intensity that can be distinguished.

  The optical path length of the dirt diffuse reflected light L3 can be calculated in advance. Therefore, the circuit unit 70 projects the irradiation light L0 from the laser diode 10 and then the second photodiode during the dirt determination time determined based on the time during which the laser light propagates the optical path length of the dirt diffuse reflected light L3. 45 is activated, and the detection value of the second photodiode 45 is acquired.

  If the detected value of the second photodiode 45 is equal to or greater than the predetermined dirt determination intensity, it is determined that the dirt 84 is attached to the housing window 82 at the irradiation angle of the irradiation light L0. On the contrary, if the detection value of the second photodiode 45 is smaller than the dirt determination intensity, it is determined that the dirt 84 is not attached at the angle at which the irradiation light L0 of the housing window 82 is irradiated.

  On the other hand, the circuit unit 70 reduces the gain of the first photodiode 20 until the laser light propagates through the optical path length of the dirt diffused reflected light L3 after the irradiation light L0 is projected from the laser diode 10. In addition, after the lapse of time, the gain of the first photodiode 20 is set as a gain at the time of object detection. As a result, the first photodiode 20 does not saturate even when it receives the dirt diffuse reflected light L3, so that it is possible to suppress the occurrence of a time during which the external reflected light L1 cannot be received.

[Summary of First Embodiment]
As described above, in the first embodiment described above, the second photodiode 45 can detect the dirt diffuse reflected light L3 with a received light intensity distinguishable from the normal diffuse reflected light L2. Therefore, it can be determined from the detection value of the second photodiode 45 whether or not the impermeable dirt 84 is attached to the housing window 82.

  Since the second photodiode 45 is provided separately from the first photodiode 20 for detecting an object outside the apparatus, it is necessary to detect the contamination of the housing window 82 using the first photodiode 20. Absent. Therefore, since the detection value of the first photodiode 20 can be suppressed from being saturated by the dirt diffused reflected light L3, it is possible to prevent the time when the object outside the apparatus cannot be detected due to the dirt of the housing window 82. it can.

  In the present embodiment, the second photodiode 45 is fixed to the perforated mirror 40. The perforated mirror 40 is a member that reflects the externally reflected light L <b> 1 reflected by the rotating mirror 50 in the direction of the first photodiode 20. Therefore, in the present embodiment, the second photodiode 45 is arranged in a direction in which the rotary mirror 50 reflects the external reflected light L1.

  The rotating mirror 50 reflects the externally reflected light L1 reflected from various directions in the direction of the perforated mirror 40. As a result of the reflection of the part of the dirt diffused reflected light L3 reflected by the dirt 84 attached to the housing window 82 by the rotating mirror 50, the external reflected light L1 is reflected by the rotating mirror 50. Irradiation light L0 is reflected in the incident direction regardless of the angle at which dirt 84 is attached.

  Therefore, the dirt diffused reflected light L3 generated at various locations of the housing window 82 can be detected by one second photodiode 45. Therefore, since it is not necessary to prepare the second photodiode 45 for each angle at which the dirt 84 needs to be detected in the housing window 82, the second photodiode 45 can be reduced. In addition, by detecting the direction of the rotating mirror 50, it is possible to determine which direction the dirt 84 is attached.

  Further, since the second photodiode 45 is disposed on the light projecting portion side surface 43 of the perforated mirror 40, the second photodiode 45 is disposed closer to the laser diode 10 than the perforated mirror 40 is. With this arrangement, the maximum reflection direction component of the normal diffuse reflected light L2 is easily blocked by the perforated mirror 40, so that the second photodiode 45 is prevented from receiving the normal diffuse reflected light L2.

  On the other hand, since the dirt diffused reflected light L3 undergoes Lambertian diffuse reflection, a part of the dirt diffused reflected light L3 is reflected by the rotating mirror 50 and passes through the through hole 42 of the perforated mirror 40. Therefore, the dirt diffuse reflected light L3 can be received by the second photodiode 45 even when the second photodiode 45 is disposed on the light projecting portion side surface 43 of the perforated mirror 40.

  In the present embodiment, the diffuse reflection member 44 that diffusely reflects the dirt diffuse reflection light L3 is provided. Therefore, as long as the second photodiode 45 faces the diffuse reflection member 44, the dirt diffuse reflection light L3 can be received. Therefore, design and assembly are facilitated.

  In the present embodiment, the second photodiode 45 is arranged such that the light receiving surface faces the direction in which the housing window 82 is not formed. Therefore, the second photodiode 45 does not directly receive the normal diffuse reflected light L2 reflected by the housing window 82.

  The rotating mirror 50 is disposed in a direction that is not the direction of the maximum intensity of the normal diffuse reflected light L2. Since the normal diffuse reflected light L2 is diffusely reflected with an intensity distribution similar to the normal distribution, if the rotating mirror 50 is arranged in a direction other than the maximum intensity direction of the normal diffuse reflected light L2, it is reflected by the rotating mirror 50. The intensity of the normal diffuse reflected light L2 is low. Therefore, it is also suppressed that the normal diffuse reflected light L2 is reflected by the rotating mirror 50 and received by the second photodiode 45 with a strong intensity.

  On the other hand, since the dirt diffused reflected light L3 is reflected light subjected to Lambert diffused reflection, a part of the dirt diffused reflected light L3 is reflected by the rotating mirror 50 while maintaining a high intensity. Since the dirt diffused reflected light L3 reflected by the rotating mirror 50 is reflected by the diffuse reflecting member 44, the dirt diffused reflected light L3 can be received by the second photodiode 45.

Second Embodiment
Next, a second embodiment will be described. In the following description of the second embodiment, elements having the same reference numerals as those used so far are the same as elements having the same reference numerals in the previous embodiments unless otherwise specified. Further, when only a part of the configuration is described, the above-described embodiment can be applied to the other parts of the configuration.

  In the first embodiment, the diffuse reflection member 44 is fixed to the perforated mirror 40. However, as shown in FIG. 4, the laser radar device 100 of the second embodiment places the diffuse reflection member 44 in the through hole 42. It is located above and near the laser diode 10. When the diffuse reflection member 44 is disposed at the position shown in FIG. 4, the diffuse reflection member 44 is fixed to the housing 80 with a fixing member (not shown).

  Since the position of the diffuse reflection member 44 is above the through hole 42, the dirt diffuse reflection light L3 hits the diffuse reflection member 44 even at the position shown in FIG. The light is received by the second photodiode 45 by being diffusely reflected. In FIG. 4, the second photodiode 45 is disposed at the same position as in the first embodiment, but the light receiving surface of the second photodiode 45 may be directed toward the diffuse reflection member 44.

  As shown in the second embodiment, the diffuse reflection member 44 may not be fixed to the perforated mirror 40.

<Third Embodiment>
As shown in FIG. 5, in the laser radar device 200 of the third embodiment, the diffuse reflection member 44 is arranged around the through hole 42 on the light projecting portion side surface 43 of the perforated mirror 40 as in the previous embodiments. Has been. However, the arrangement of the diffuse reflection member 44 with respect to the through hole 42 is different from the previous embodiments. In the laser radar device 200 of the third embodiment, the diffuse reflection member 44 is disposed in the front direction of the laser radar device 200 with respect to the through hole 42.

  On the other hand, the second photodiode 45 is disposed at the end opposite to the housing window 82 on the light projecting portion side surface 43 of the perforated mirror 40.

  Even in this arrangement, as shown in FIG. 5, the diffuse reflection member 44 is struck with the dirt diffuse reflection light L3, and the dirt diffuse reflection light L3 reflected by the diffuse reflection member 44 is received by the second photodiode 45. The

<Fourth embodiment>
As shown in FIG. 6, the laser radar device 300 according to the fourth embodiment differs from the previous embodiments in the inclination direction of the perforated mirror 40. In the fourth embodiment, the perforated mirror 40, the diffuse reflection member 44, the second photodiode 45, and the first photodiode 20 are rotated 180 degrees with the optical axis of the laser diode 10 as the axis of symmetry.

  Therefore, the perforated mirror 40 is inclined such that the reflection surface 41 is positioned downward as it is farther from the housing window 82. Further, the first photodiode 20 is arranged in the front direction of the laser radar device 300 with respect to the perforated mirror 40.

  The diffuse reflection member 44 is disposed around the through hole 42 and on the housing window 82 side on the light projecting portion side surface 43 of the perforated mirror 40. The second photodiode 45 is disposed at the rear surface 81 side end of the housing 80 on the light projecting portion side surface 43 of the perforated mirror 40.

  Even in such an arrangement, as shown in FIG. 6, the diffuse reflection member 44 is struck with the dirt diffuse reflection light L 3, and the dirt diffuse reflection light L 3 reflected by the diffuse reflection member 44 is received by the second photodiode 45. .

<Fifth Embodiment>
As shown in FIG. 7, the laser radar device 400 according to the fifth embodiment does not include the perforated mirror 40 but includes a deflection mirror 402 instead. Further, the arrangement of the laser diode 10 and the first photodiode 20 is the reverse of the previous embodiments.

  As shown in FIG. 7, in the laser radar device 400 of the fifth embodiment, the irradiation light L <b> 0 projected from the laser diode 10 in the front direction of the laser radar device 400 is directed toward the rotary mirror 50 by the deflection mirror 402. Deflected.

  The externally reflected light L1 is reflected by the concave mirror 51 of the rotary mirror 50 and deflected in the direction toward the upper side of the apparatus. Since the first photodiode 20 is disposed above the rotating mirror 50, the externally reflected light L1 is received by the first photodiode 20.

  In the fifth embodiment, the second photodiode 45 is arranged above the rotating mirror 50 in a posture in which the light receiving surface faces the direction of the concave mirror 51. Accordingly, the dirt diffused reflected light L3 reflected by the concave mirror 51 is received by the second photodiode 45.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to the above-mentioned embodiment, The following modification is also contained in the technical scope of this invention, Furthermore, the summary other than the following is also included. Various modifications can be made without departing from the scope.

<Modification 1>
In the above-described embodiment, the diffuse reflection member 44 is used. However, a reflection member whose surface is a mirror surface (hereinafter, a mirror reflection member) may be used. When the specular reflection member is used, the angle of the specular reflection member is adjusted so that the dirt diffuse reflection light L3 can be reflected in the direction of the second photodiode 45 in accordance with the law of reflection.

<Modification 2>
The shape of the diffuse reflection member is not limited to the shape of the above-described embodiment. For example, the diffuse reflection member may have a flat plate shape. Moreover, the shape where several flat plate shape was connected may be sufficient. Moreover, the diffuse reflection member 44 of the above-described embodiment has a shape that surrounds a half or more of the through hole 42. However, the diffuse reflection member 44 may have a shorter length than that of the above-described embodiment. Since the dirt diffuse reflected light L3 is generated by Lambertian diffuse reflection, there are components directed in various directions. Therefore, even if the length of the diffuse reflection member is short, a part of the dirt diffuse reflection light L3 hits the diffuse reflection member. The diffuse reflection member diffusely reflects the dirt diffuse reflected light L3. Therefore, even if the length of the diffuse reflection member is short, the diffuse reflection member can reflect the dirt diffuse reflection light L3 in the direction of the second photodiode 45.

<Modification 3>
The material of the diffuse reflection member is not limited to paper, and the material is not limited as long as the surface shape is not a mirror surface.

<Modification 4>
In the above-described embodiment, the scanning angle range is 180 degrees, but the scanning angle range may be wider than 180 degrees. The scanning angle range may be 360 degrees, for example. Conversely, the scanning angle range may be narrower than 180 degrees.

DESCRIPTION OF SYMBOLS 1: Laser radar apparatus 10: Laser diode 20: 1st photodiode 30: Collimating lens 40: Perforated mirror 41: Reflecting surface 42: Through-hole 43: Light projecting part side surface 44: Diffuse reflection member 45: 2nd photodiode 50 : Rotating mirror 51: concave mirror 60: motor 61: rotating shaft 62: rotation angle position sensor 70: circuit unit 80: housing 81: back surface 82: housing window 100: laser radar device 200: laser radar device 300: laser radar device 400: Laser radar device 402: Deflection mirror L0: Irradiation light L1: External reflection light L2: Normal diffuse reflection light L3: Diffuse reflection light

Claims (5)

A light projecting unit (10) for generating and projecting laser light;
A housing window (82) through which the laser light projected by the light projecting unit and external reflected light generated by reflecting the laser light on an external object pass;
A light receiving sensor (20) for externally reflected light that receives the externally reflected light;
A laser radar device (1, 100, 200, 300, 400) comprising:
When the opaque light is attached to a portion of the housing window through which the laser light passes, the diffused diffused reflected light, which is reflected light generated by the laser light reflected by the dirt, is converted into the housing window. In a position where the laser beam can be received with a light receiving intensity that is distinguishable from the normal diffuse reflected light that is reflected when the laser beam passes through the housing window when no dirt is attached to the portion through which the laser beam passes. A laser radar apparatus comprising a dirt detection light receiving sensor (45) different from the external reflection light receiving sensor. In claim 1,
A rotating mirror (50) that reflects the laser light projected by the light projecting unit in the direction of the housing window while rotating, and reflects the externally reflected light in the incident direction of the laser light,
The laser radar apparatus according to claim 1, wherein the dirt detection light receiving sensor is arranged in a direction in which the rotating mirror reflects the externally reflected light. In claim 2,
Between the light projecting unit and the rotating mirror, there is a through hole (42) through which the laser light projected by the light projecting unit passes and reaches the rotating mirror, and the rotating mirror side is a reflecting surface. (41), provided with a perforated mirror (40) for reflecting the externally reflected light reflected by the rotating mirror in the direction of the light receiving sensor for externally reflected light,
The housing window is inclined such that the maximum intensity direction of the normal diffuse reflected light is the perforated mirror direction rather than the rotating mirror,
The laser radar apparatus according to claim 1, wherein the dirt detection light receiving sensor is disposed on an optical path of the dirt diffuse reflected light on the light projecting unit side with respect to the perforated mirror. In any one of Claims 1-3,
A diffusive reflecting member (44) disposed on an optical path of the dirt diffuse reflected light and having a surface shape for further diffuse reflecting the dirt diffuse reflected light;
The laser radar apparatus according to claim 1, wherein the dirt detection light receiving sensor is disposed at a position facing the diffuse reflection member. In claim 2,
The housing window is formed on a part of the entire circumference of the laser radar device,
The rotating mirror is a direction that is not the maximum intensity direction of the normal diffuse reflected light, and is disposed at a position that reflects the dirt diffuse reflected light,
The dirt detection light receiving sensor has a light receiving surface facing a direction in which the housing window is not formed,
A reflection member (44) is provided on the optical path of the dirt diffused reflected light reflected by the rotating mirror and reflects the dirt diffused reflected light toward the dirt detecting light receiving sensor. Laser radar device.

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