JP2013068582A - Laser radar device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a constitution capable of effectively preventing an erroneous detection caused by an external disturbance light by attaining a sure constraint against that an internal reflection light (external disturbance light) generated by a cover is entered into a photo-sensor.SOLUTION: In a laser radar device 1, a filter member 90 is arranged at a front and lower side of a light receiving surface 20a of a photo-diode 20, and this filter member 90 is configured to have an angle dependence for restricting a transmission in proportion as an angle made with a lower surface 90a of the filter member 90 becomes smaller, and so as to restrict the transmission of the external disturbance light in an oblique direction toward the photo-sensor side from a transmission plate 80. With regard to a normal reflection light (reflection light from a subject in the external space) to be guided upward by a concave mirror 41, since the filter member 90 is constituted so as to transmit as for the light in the vertical direction, it becomes hard to be restricted when transmitting through the filter member 90.

Description

  The present invention relates to a laser radar device.

  Currently, as a technique for detecting an object using laser light, for example, an apparatus as disclosed in Patent Document 1 is provided. In the apparatus of Patent Document 1, an optical isolator is provided on the optical axis of the laser light from the laser light generating means, and the optical isolator transmits the laser light from the laser light generating means and reflects it from the detection object. Light is reflected on the light receiving sensor side. Further, on the optical axis of the laser beam that has passed through the optical isolator, a concave mirror that can rotate 360 ° about the central axis in the optical axis direction is provided, and this concave mirror reflects the laser beam toward the space. At the same time, 360 ° horizontal scanning is possible by reflecting the reflected light from the object toward the light receiving sensor. Then, by calculating the rotational position of the concave mirror when the object is irradiated with the laser beam and calculating the time until the laser beam is received by the calculation unit (object position calculation unit) provided in the apparatus, The direction and distance of the object are calculated.

Japanese Patent Laid-Open No. 10-20035 JP 2008-216238 A

  By the way, many of the above laser radar devices are provided with a cover for the purpose of dustproofing, dripproofing, etc. on the irradiation path of the laser light irradiated to the external space from the deflecting unit (for example, a concave mirror). Is provided with a light-transmitting cover (light-transmitting cover) so that the laser light irradiated toward the external space can be transmitted. However, when the cover is provided on the irradiation path of the laser light in this way, a part of the laser light irradiated to the space from the deflecting unit (that is, the laser light trying to pass through the cover) is reflected on the surface of the cover. Therefore, the reflected light (disturbance light) may be received by a light receiving sensor disposed in the apparatus. When disturbance light is received by the light receiving sensor in this way, the calculation means (object position calculation means) misrecognizes the detected disturbance light as reflected light from the object, and the object is detected in the external space. There is a concern of misjudging it.

  In addition, if a part of the laser light radiated to the external space is specularly reflected by the cover (light-transmitting cover), the amount of received light is equivalent when disturbance light generated by the specular reflection is received by the light receiving sensor. There is a possibility that the light receiving sensor reaches a saturation state (light receiving state exceeding a light receiving amount that generates the maximum light receiving signal). In particular, in the above laser radar device, it is necessary to set the sensitivity of light reception at the light receiving sensor to a certain level so that diffuse reflected light can be detected when an object existing in the external space is irradiated with laser light. When specularly reflected light (disturbance light) having a significantly larger light quantity than the reflected light is received, the possibility that the light receiving sensor will be saturated becomes extremely high. Once the light reception is saturated in this way, a large light reception signal continues to be output from the light reception sensor until a certain amount of time elapses even after specular reflection light (disturbance light) does not enter the light reception sensor. Since the saturated state continues (delays), the reflected light that should be detected may not be detected correctly until the saturated state is canceled.

  In addition, a method of removing specular reflection light (disturbance light) generated by the cover (light transmissive cover) as noise can be considered. However, with such a method alone, the light reception timing of the specular reflection light (disturbance light) is as described above. It is not possible to deal with cases where disturbance light is difficult to remove, such as when the reflected light timing of normal reflected light is close (such as when a detection object is present near the cover).

For the above reasons, a laser radar device is desired to have a configuration in which specular reflection light (disturbance light) generated by a cover (light transmissive cover) is not easily received by a light receiving sensor.
In order to deal with such problems, the inventor considered that the disturbance light is not easily received by the light receiving sensor, and arranged a member on the disturbance light path to block the disturbance light incident path. However, it has also been found that demerit is great if a simple shielding member is disposed on the path from the cover (light transmissive cover) to the light receiving sensor. For example, when the ambient light is blocked by the shielding member as described above, the shielding member needs to be configured to be somewhat large in order to more reliably block the light. In addition, it is difficult to dispose the shielding member by removing it from the light receiving path, and it is unavoidable to increase the size of the apparatus configuration if it is attempted to avoid the light projecting path or the light receiving path. Although a method of reducing the size by interposing a part of the shielding member in the light receiving path is also conceivable, in such a configuration, a part of the reflected light (reflected light from the detection object) taken into the apparatus is used. Cannot be used as a light receiving signal, and the light receiving sensitivity is reduced.

  The present invention has been made to solve the above-described problems, and in a laser radar device in which a light-transmitting cover is disposed on a laser light irradiation path, internally reflected light (disturbance light) generated by the cover. It is an object of the present invention to provide a configuration that can more reliably prevent light from entering the light receiving sensor and can effectively prevent erroneous detection due to ambient light.

The present invention has been made to solve the above problems,
A laser light generating means comprising a laser light source for generating laser light, and configured to guide the laser light from the laser light source in a predetermined vertical direction;
A deflection unit configured to be rotatable about a central axis along the vertical direction; and a driving unit that rotationally drives the deflection unit, and the laser beam generation unit rotates the deflection unit and moves the vertical direction. The deflecting unit deflects the laser light guided to the external space around the deflecting unit, and the deflected laser light is reflected by an object existing in the external space to generate reflected light. Rotational deflection means that reflects upward and guides it to the light receiving path,
A light receiving sensor for receiving the reflected light guided to the light receiving path by the deflection unit;
A case in which at least the light receiving sensor and the deflection unit are accommodated, and the laser beam scanning path is blocked by a transmission plate capable of transmitting the laser beam at least in a circumferential direction around the deflection unit; ,
With
The light receiving sensor is disposed above the position where the laser light emitted from the deflection unit is incident on the transmission plate,
The portion of the transmission plate on which the laser light is incident is disposed such that the incident surface of the laser light is inclined with respect to the central axis and faces upward.
The direction of a virtual line orthogonal to the axis of the central axis and passing through the center of the light receiving surface of the light receiving sensor is the front-rear direction, the side facing the light receiving surface of the light receiving sensor is the front side, and the side opposite to the light receiving surface Is a front side and a lower side of the light receiving surface, and a part of the laser light from the deflection unit is reflected by the transmission plate on the light receiving path above the deflection unit. A filter member that suppresses disturbance light generated by
The filter member has an angle dependency that transmits light in the vertical direction and suppresses transmission as light having a smaller angle with the filter member, and the reflection guided upward from the deflection unit. It is configured to transmit light and suppress transmission of the disturbance light in an oblique direction from the transmission plate toward the light receiving sensor side.

In the first aspect of the invention, since the inner surface (laser beam incident surface) of the laser beam incident portion of the transmission plate is arranged so as to be inclined with respect to the central axis and directed upward, the laser beam from the deflection unit When a part of the light is reflected by the transmission plate and disturbing light is generated, the disturbing light is directed in the upper direction (obliquely upward) inclined with respect to the central axis.
In such a configuration, it is difficult for disturbance light generated by reflection from the transmission plate to directly enter the deflecting unit, but disturbance light generated by the transmission plate when the laser beam is irradiated from the deflection unit to the front side. There is a concern that light will be received by the light receiving sensor on the rear side and the obliquely upper side.
Therefore, in the present invention, a filter member having a property (angle dependency) that suppresses transmission as light having a smaller angle with the lower surface is disposed on the front side and the lower side of the light receiving surface of the light receiving sensor. Transmission of disturbance light in an oblique direction toward the light receiving sensor side is suppressed.
In this configuration, the regular reflected light (reflected light from the object in the external space) guided upward by the deflecting unit is incident on the lower surface of the filter member in a highly transmissive direction (a direction close to the vertical direction). Therefore, it is difficult to be suppressed by the filter member, and the light can be guided more reliably to the light receiving sensor side. On the other hand, disturbance light reflected by the transmission plate and traveling obliquely upward is incident on the lower surface of the filter member in a direction with low transparency (an inclined direction shifted by a certain angle from the vertical direction). The filter member can more reliably block the transmission upward.
In particular, in this configuration, the arrangement relationship between the transmission plate and the filter member is a characteristic arrangement relationship, and the functions of the filter member having an angle dependency (the function of transmitting normal light and the function of blocking disturbance light) are provided. In order to make full use, the transmission plate arranged around the deflection unit is inclined, and the incident direction in which the regular reflected light is incident on the lower surface of the filter member and the disturbance light reflected by the transmission plate and directed obliquely upward are generated. An angle difference is easily generated depending on the direction of incidence when entering the lower surface of the filter member. And since the filter member is arrange | positioned in the characteristic place where the angle difference becomes very remarkable, the permeation | transmission effect of regular light and the blocking effect of disturbance light can each be made conspicuous.

According to a second aspect of the present invention, in the cut surface obtained by cutting the laser radar device along a plane passing through the central axis and passing through the center of the light receiving surface, the deflecting unit extends from the deflection unit to the external space. A virtual first extension line extending upward through the incident position of the laser beam when irradiated on the inner surface of the transmission plate and the front end of the filter member on the cut surface is set, and A virtual second extension extending upward through the incident position of the laser beam on the inner surface of the transmission plate and the rear end of the filter member in the cut surface when the external space is irradiated along the cut surface When a line is set, the light receiving surface of the light receiving sensor is disposed at a position deviating from the first extension line in a region below the first extension line, and an area above the second extension line In the second It is configured to be disposed out of the long line position.
According to this configuration, in the irradiation direction in which the influence of disturbance light is most concerned (that is, when the laser beam is irradiated from the deflecting unit to the front side), the disturbance light directed directly from the transmission plate to the light receiving surface of the light receiving sensor. Can be reliably suppressed by the filter member. In addition, even if there is disturbance light that goes in a direction away from the filter member, the disturbance light does not directly enter the light receiving sensor, so that it is easier to suppress the influence of the disturbance light on the light receiving sensor. .

According to a third aspect of the present invention, the filter member is disposed on a path of specular reflection light when a part of the laser light irradiated forward from the deflecting unit along the cut surface is specularly reflected by the transmission plate. Has been.
In this configuration, the specular reflection component having a large energy can be reliably suppressed in the irradiation direction in which the influence of disturbance light is most concerned (that is, when the laser beam is irradiated from the deflection unit to the front side). A large shielding action can be produced.

According to a fourth aspect of the present invention, the front end portion of the filter member is located at a part of the path of the laser light guided in the vertical direction by the laser light generating means, or deviates to the rear side from the path. Is arranged.
In this configuration, since the filter member does not intervene in the entire laser light projection path and all of the laser light from the laser light generation means does not enter the filter member, attenuation during light projection caused by the filter member is suppressed. Can do.

In the invention of claim 5, the filter member is formed with a through hole or a notch communicating in the vertical direction, and the laser beam guided in the vertical direction by the laser light generating means is in the through hole or the It passes through the notch and is configured to enter the deflection unit.
In this configuration, since the laser light from the laser light generating means does not pass through the inside of the filter member, attenuation during light projection caused by the filter member can be more effectively suppressed. In addition, the filter member can be arranged evenly around the light projecting path rather than being disposed only on one side of the light projecting path.

According to a sixth aspect of the present invention, a passage hole through which the laser light guided in the vertical direction by the laser light generating means passes is formed above the deflection unit in the light receiving path, and the reflected light from the deflection unit A reflection mirror that reflects the light from the rear is provided, the light receiving sensor is provided on the rear side of the reflection mirror, and the filter member is provided at a position between the reflection mirror and the deflection unit.
In this configuration, the light receiving sensor can be arranged on the side of the reflecting mirror, and the light receiving sensor does not have to be arranged so much in the upper position. If the light receiving sensor is disposed on the lower side to some extent in this way, the degree of disturbance light that travels from the transmission plate toward the light receiving sensor is increased, and the transmission suppressing effect of the filter member is further enhanced.

FIG. 1 is a cross-sectional view schematically illustrating the overall configuration of the laser radar apparatus according to the first embodiment. FIG. 2 is a cross-sectional view schematically showing a cross section of the laser radar device of FIG. 1 cut in the horizontal direction. FIG. 3 is an enlarged view schematically showing a part of the laser radar device of FIG. FIG. 4 is an explanatory diagram for explaining the relationship between the disturbance light generated by reflection on the transmission plate and the filter member in the laser radar apparatus of FIG. FIG. 5 is a cross-sectional view schematically illustrating a part of the laser radar device according to the second embodiment. FIG. 6 is a cross-sectional view schematically illustrating a part of the laser radar device according to the third embodiment.

[First embodiment]
Hereinafter, a first embodiment of a laser radar device according to the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view schematically illustrating the overall configuration of the laser radar apparatus according to the first embodiment. FIG. 2 is a cross-sectional view schematically showing a cross section of the laser radar device of FIG. 1 cut in the horizontal direction. FIG. 3 is an enlarged view schematically showing a part of the laser radar device of FIG. FIG. 4 is an explanatory diagram for explaining the relationship between the disturbance light generated by reflection on the transmission plate and the filter member in the laser radar apparatus of FIG.

(overall structure)
First, the overall configuration of the laser radar device according to the first embodiment will be described with reference to FIGS. 1 and 2.
FIG. 1 schematically shows a cut surface obtained by cutting the laser radar device 1 along the central axis 42a so as to pass through the center position P2 of the light receiving surface 20a of the photodiode 20 and the central axis 42a. 1 schematically shows an enlarged part of the cut surface of FIG. In the following description, the cross section of the transparent plate is shown in white.

  As shown in FIG. 1, the laser radar device 1 includes a laser diode 10 and a photodiode 20 that receives reflected light L2 from a detection object, and is configured as a device that detects the distance and direction to the detection object. Yes.

  The laser diode 10 corresponds to an example of a “laser light source”, receives a pulse current from a drive circuit (not shown) under the control of the control circuit 100, and generates a pulse laser beam (laser beam L1) corresponding to the pulse current. It emits intermittently. In the present embodiment, laser light from the laser diode 10 to the detection object is conceptually indicated by symbol L1, and reflected light from the detection object to the photodiode is conceptually indicated by symbol L2. Yes.

The photodiode 20 is composed of, for example, an avalanche photodiode. When the laser light L1 is generated from the laser diode 10 and the laser light L1 is reflected by a detection object (not shown), the photodiode 20 receives the reflected light L2 and converts it into an electrical signal. In addition, about the reflected light from a detection object, the thing of a predetermined area | region is taken in into the concave mirror 41, and in FIG. 1, the reflected light of the area | region between two lines (two-dot chain line) shown with the code | symbol L2 is taken in. An example is shown. In the example shown in FIGS. 1, 3, etc., the photodiode 20 is disposed on the rear side of a reflection mirror 30 to be described later, is located below the laser diode 10, and is lower than a filter member 90 and a concave mirror 41 to be described later. It is arranged in the upper position.
The photodiode 20 corresponds to an example of a “light receiving sensor” and functions to receive reflected light from an external object guided to a light receiving path by a concave mirror 41 described later.

  A lens 60 is provided on the optical axis of the laser light L1 emitted from the laser diode 10. The lens 60 is configured as a collimating lens, and converts the laser light L1 from the laser diode 10 into parallel light. In the present embodiment, the laser diode 10 and the lens 60 correspond to an example of “laser light generating means”, and the laser light from the laser diode 10 is directed in a predetermined vertical direction (Y-axis direction shown in FIG. 1). It functions to guide.

  In the present embodiment, a direction parallel to a later-described central axis 42a is the vertical direction (vertical direction), and in FIG. 1 and the like, the vertical direction is indicated as the Y-axis direction. A direction parallel to a plane orthogonal to the central axis 42a is defined as a horizontal direction. Further, a direction perpendicular to the axis of the central axis 42a and parallel to an imaginary line A1 (FIG. 3) passing through the center P2 of the light receiving surface 20a of the photodiode 20 is a front-rear direction, and the side on which the light receiving surface 20a of the photodiode 20 faces. Is the front side, the side opposite to the light receiving surface 20a is the rear side, and the front-rear direction is shown as the X-axis direction.

  A reflection mirror 30 is provided in the vicinity of the optical path of the laser light L1 that has passed through the lens 60. The reflection mirror 30 is disposed on the light receiving path above the concave mirror 41 described later, and a reflection surface 30a inclined at a predetermined angle with respect to the optical axis of the laser light L1 is formed on the lower surface side. The reflecting surface 30a is configured to reflect the reflected light L2 (reflected light from the external object) coming from the concave mirror 41 toward the reflecting mirror 30 backward. Further, a passage hole 32 in a direction intersecting with the reflecting surface 30a is provided, and the laser light L1 guided in the vertical direction by the above-described laser light generation means passes through the passage hole 32. . In this way, the reflection mirror 30 allows the laser light L1 from the laser diode 10 to pass through the passage hole 32, while reflecting the reflected light L2 from the external object (more specifically, the reflected light reflected by the concave mirror 41). It functions so as to be reflected toward the diode 20. Between the reflection mirror 30 and the photodiode 20, an optical filter 64 that allows light of a predetermined wavelength to pass therethrough and a condenser lens 62 that further collects light from the reflection mirror 30 are disposed.

  A rotary reflection device 40 is provided on the optical axis of the laser beam L1 that passes through the reflection mirror 30. The rotary reflection device 40 corresponds to an example of a “rotation deflecting unit”, and includes a concave mirror 41 configured to be rotatable about a central axis 42 a extending in the vertical direction, and a shaft portion 42 coupled to the concave mirror 41. And a bearing (not shown) that rotatably supports the shaft portion 42 and a motor 50 that rotationally drives the concave mirror 41, while the concave mirror 41 is rotated by the laser light generating means (laser diode 10 and lens 60) described above. The laser beam L1 guided in the vertical direction functions to be deflected by the concave mirror 41 toward an external space around the concave mirror 41 (a space outside the laser radar device 1). In addition, the rotary reflection device 40 reflects the reflected light L2 that is generated when the laser beam L1 deflected by the concave mirror 41 and applied to the external space is reflected by an object existing in the external space, and reflected by the concave mirror 41 upward. Is functioning to lead to.

  The concave mirror 41 corresponds to an example of a “deflection unit”, and includes a concave reflection surface 41a disposed on the optical axis of the laser light L1 that has passed through the reflection mirror 30, and a central axis 42a (predetermined center). The laser beam L1 from the laser diode 10 is deflected (reflected) toward the space outside the case 3 and from an object existing in the space outside the case 3 (external space). The reflected light L <b> 2 is deflected (reflected) toward the photodiode 20.

  The direction of the central axis 42a that is the rotation center of the concave mirror 41 substantially coincides with the direction of the laser light L1 that passes through the reflecting mirror 30 and enters the concave mirror 41, and the laser light L1 enters the concave mirror 41. The incident position P1 is a position on the central axis 42a. In the present embodiment, the portion near the position P1 on the reflection surface 41a of the concave mirror 41 is inclined at an angle of 45 ° with respect to the vertical direction (the direction of the laser beam L1 incident on the reflection surface 41a). The laser beam L1 reflected by the reflection surface 41a of 41 is irradiated in the horizontal direction. Further, since the concave mirror 41 rotates around the central axis 42a in the direction coinciding with the direction of the incident laser light L1, the incident angle of the laser light L1 is always maintained at 45 ° regardless of the rotational position of the concave mirror 41, The direction of the laser beam L1 from P1 is configured to be always in the horizontal direction (direction orthogonal to the central axis 42a).

  The motor 50 corresponds to an example of “driving means”, and rotates the shaft portion 42 to rotationally drive the concave mirror 41 connected to the shaft portion 42 around the central shaft 42a. The motor 50 is constituted by, for example, a known DC motor or a known AC motor. When a drive instruction is issued from the control circuit 100, the motor 50 is driven by a motor driver (not shown) (for example, rotation timing or rotation speed). Is controlled, and at this time, it is rotated constantly at a predetermined constant rotational speed.

  In the motor 50, for example, a rotational drive shaft is configured integrally with the shaft portion 42, and the shaft portion 42 and the concave mirror 41 are configured to rotate regularly around the central shaft 42a. The concave mirror 41 is arranged so that the angle θ formed between the deflection surface (reflection surface 41a) and the central axis 42a is a constant angle (for example, 45 °) as described above, and receives the driving force of the motor 50. Further, the rotation is performed while maintaining the angle θ at a constant angle.

  In the present embodiment, as shown in FIG. 1, a rotation angle sensor 52 that detects the rotation angle position of the shaft portion 42 of the motor 50 (that is, the rotation angle position of the concave mirror 41) is provided. Various types of rotation angle sensors 52 can be used as long as they can detect the rotation angle position of the shaft portion 42, such as a rotary encoder.

  In the laser radar device 1, the laser diode 10, the photodiode 20, the reflection mirror 30, the lens 60, the rotary reflection device 40, and the like are accommodated in the case 3 so that dust protection and impact protection are achieved. The case 3 includes a main case portion 5 and a transmission plate 80, and is configured in a box shape as a whole. The laser beam L1 is scanned on the scanning path of the laser beam L1 at least at a part in the circumferential direction around the concave mirror 41. Is configured to be closed by a transmissive plate 80 that can transmit light. The main case portion 5 is arranged such that the upper wall portion 5a and the lower wall portion 5b are opposed to each other in the vertical direction, the front wall portion 5c and the rear wall portion 5d are arranged opposed to each other in the front-rear direction, and the side wall portions 5e and 5f are left and right. They are arranged to face each other and have a box-like shape that is partially opened so that light can be guided.

  In the main case portion 5, a window portion 4 that allows the laser light L <b> 1 and the reflected light L <b> 2 to pass therethrough is formed around the concave mirror 41. The window portion 4 is a portion opened so as to allow light to enter and exit from the main case portion 5, and is formed in a groove shape from the front wall portion 5c of the main case portion 5 to both side wall portions 5e and 5f. ing. A transmission plate 80 is provided so as to close the window portion in the form of the opening.

  The transmission plate 80 is made of, for example, a transparent resin plate, a glass plate, or the like, and is a window disposed on the scanning path of the laser light L1 over approximately a half circumference around the concave mirror 41 as shown in FIG. It arrange | positions by the structure which obstruct | occludes the part 4. FIG. The transmission plate 80 is disposed over a predetermined range in the circumferential direction on the scanning path of the laser light L1 from the concave mirror 41, closes the window 4 and transmits the laser light L1 projected from the concave mirror 41. It has a configuration.

(Configuration of filter member)
Next, the filter member 90, which is one of the features of the laser radar device 1, and the configuration related thereto will be described.
First, the arrangement relationship of the photodiode 20, the transmission plate 80, and the filter member 90 will be described. As shown in FIGS. 1 and 3, in the laser radar device 1, the laser light L <b> 1 emitted from the concave mirror 41 is incident on the transmission plate 80 in the inner region of the case 3 when the direction of the central axis 42 a is the vertical direction. The photodiode 20 is arranged in a region above the position to be positioned (a position on a virtual plane orthogonal to the central axis 42a and passing through the position P3).

  A filter member 90 is disposed on the front side and the lower side of the photodiode 20. The filter member 90 is disposed on the light receiving path above the concave mirror 41 on the front side and the lower side of the light receiving surface 20a. In the present embodiment, when the reflected light generated by reflecting the laser beam irradiated from the concave mirror 41 to the external space by the object in the external space is taken into the concave mirror 41, it is reflected while being collected by the concave mirror 41. It has become. In such a configuration, the reflected light travels from the concave mirror 41 to the reflecting mirror 30 and is reflected by the reflecting mirror 30 to reach the photodiode 20 as a light receiving path. In such a light receiving path, a filter member 90 is provided at a position between the reflecting mirror 30 and the concave mirror 41.

  As shown in FIGS. 1 and 2, the transmission plate 80 is disposed on the scanning path of the laser light L1 emitted from the concave mirror 41, and is approximately half a circumference around the concave mirror 41 as shown in FIG. The concave mirror 41 is surrounded. In this embodiment, as shown in FIG. 2, when the laser beam L1 is irradiated to the position Lb from the rotation angle when the laser beam L1 is irradiated in the direction of the position La out of all the rotation angles of the concave mirror 41 that can rotate 360 °. The angle range up to the rotation angle is a detection range, and when the concave mirror 41 is in this detection range, the laser light L1 from the concave mirror 41 enters the inner surface 80a (incident surface) of the transmission plate 80. Yes. The transmission plate 80 has a laser beam L1 incident surface inclined at an angle with respect to the central axis 42a at any position in the circumferential direction around the central axis 42a. It is arranged to face the side. That is, in any of the circumferential directions, the incident position of the laser beam L1 is inclined obliquely upward.

  More specifically, even if the cut surface cut at a position on the central axis 42a is cut so as to pass through any position in the circumferential direction of the transmission plate 80, the inner shape of the transmission plate 80 at the cut surface is as shown in FIG. It has such a fixed shape. The tangent line Lc at the position where the laser beam L1 is incident on the inner surface 80a of the transmission plate 80 (P3 position in the case of FIG. 3) is inclined at a certain angle with respect to the horizontal direction in any direction of the cut surface passing through the central axis 42a. α (see FIGS. 3 and 4).

  Further, in the present embodiment, the reflecting mirror 30 and the concave mirror 41 are arranged at a predetermined interval, and the laser beam L1 from the transmission plate 80 is incident on any position in the circumferential direction of the transmission plate 80. The shape (particularly the inclination angle of the inner surface 80a) and arrangement of the transmission plate 80, and the concave mirror 41 and the reflection mirror 30 so that the specular reflection component (regular reflection component) of the disturbance light passes between the reflection mirror 30 and the concave mirror 41. The shape and arrangement are defined. In FIG. 1, FIG. 3, and FIG. 4, the specular reflection component (regular reflection component) of the reflected light (disturbance light) in which part of the laser light L1 is reflected by the inner surface 80a of the transmission plate 80 is denoted by reference numeral L3. It shows conceptually.

Next, the configuration of the filter member 90 will be described in detail.
The filter member 90 is disposed on the light receiving path above the concave mirror 41 on the front side and the lower side of the light receiving surface 20a, and disturbance light generated by part of the laser light L1 from the concave mirror 41 being reflected by the transmission plate 80. It functions to suppress. The filter member 90 is configured in a plate shape, and the lower surface 90a and the upper surface opposite thereto are disposed substantially parallel to the horizontal direction (a plane direction orthogonal to the vertical direction (Y-axis direction)), and the vertical direction ( As the light that transmits light in the Y-axis direction and the angle formed with the lower surface 90a of the filter member 90 becomes smaller, the light has an angle dependency that suppresses transmission. Then, the reflected light guided upward from the concave mirror 41 (reflected light generated when the laser beam L1 is reflected by the object in the external space and reflected by the concave mirror 41) is transmitted, and the photo is transmitted from the transmission plate 80. It is configured to suppress transmission of disturbance light in the oblique direction toward the diode 20 (reflected light generated when the laser light L1 is reflected by the transmission plate 80). The filter member itself having angle dependency is known, and a known multilayer filter, bandpass filter (interference filter), high-pass filter, low-pass filter, or the like can be used as the filter member 90.

  In other words, in this configuration, the reflecting mirror 30 is disposed directly above the concave mirror 41, and the direction of the reflected light when the reflected light from the object in the external space is reflected toward the reflecting mirror 30 while being collected by the concave mirror 41 Since there is a lot of light with a small angle with the vertical direction or with the vertical direction (that is, there is a lot of light with a large angle with the lower surface 90a of the filter member 90), part of the light has entered the filter member 90. However, the filter member 90 transmits light without being suppressed so much. On the other hand, since the transmissive plate 80 is disposed on the side of the concave mirror 41 and is disposed on the side of the filter member 90 to some extent, a part of the laser beam L1 from the concave mirror 41 is reflected by the transmissive plate 80. When the disturbance light generated in this way directly enters the filter member 90, the angle formed by the direction of the disturbance light and the lower surface 90a of the filter member 90 becomes small.

  More specifically, than the angle formed between the direction of the reflected light when the regular reflected light from the concave mirror 41 (reflected light from the object in the external space) enters the lower surface 90a of the filter member 90 and the lower surface 90a, The angle between the direction of the ambient light generated when the ambient light reflected by the transmission plate 80 directly enters the filter member 90 and the angle between the lower surface 90a of the filter member 90 is much smaller, and the ambient light is reliably attenuated. It can be made to. More specifically, when the regular reflected light from the concave mirror 41 (reflected light from the object in the external space) enters the lower surface 90a of the filter member 90, the component of the reflected light that is inclined most with respect to the vertical direction. The disturbance light generated when the disturbance light reflected by the transmission plate 80 directly enters the filter member 90 is larger than the angle formed by the direction (the component having the largest angle with the vertical direction) and the lower surface 90a. The direction of the component that is not inclined relative to the vertical direction (the component that has the smallest angle with the vertical direction) and the angle formed with the lower surface 90a of the filter member 90 are smaller.

  Specifically, as shown in FIG. 3, when the laser beam L1 is irradiated forward, the positional relationship as shown in FIG. The angle between the reflection direction La and the horizontal direction at the end P4 when light from outside (reflected light) enters the horizontal with respect to the concave mirror 41 is θ1, and the angle between the reflection direction La and the vertical direction is θ1. When A1 is A1, A1 = 90−θ1, and A1 is an incident angle when reflected light traveling upward from the end P4 is incident on the lower surface 90a. It is desirable that the configuration of the reflection direction La and the filter member 90 is adjusted so that the light in the reflection direction La is transmitted almost 100%.

  Further, as shown in FIG. 4, when the angle between the direction (front-rear direction) when the laser light L1 is emitted forward from the concave mirror 41 and the specular reflection light L3 generated by specular reflection at the position P3 is X1. X1 = 180−2α. The incident position P1 of the laser light L1, the inclination angle α of the transmission plate 80, and the arrangement of the filter member 90 are adjusted so that the mirror reflection light L3 is in a positional relationship to enter the filter member 90. desirable. Further, it is desirable that the filter member 90 has a configuration in which the transmittance is substantially zero when the angle formed between the incident light and the lower surface 90a is X1 (that is, when X1 = 180-2α).

  In addition, assuming that Gaussian diffusion is performed in the range of an angle β around the path L3 of the specular reflection light, the direction (front-rear direction) when the laser light L1 is emitted forward from the concave mirror 41 and the Gaussian diffusion light The angle X2 formed with the upper boundary route L4 is X2 = 180-2α + β. The incident position P1 of the laser light L1, the inclination angle α of the transmission plate 80, and the arrangement of the filter member 90 are adjusted so that the light is incident on the filter member 90 in such a positional relationship. desirable. Further, it is desirable that the filter member 90 has a configuration in which the transmittance is substantially zero when the angle formed between the incident light and the lower surface 90a is X2 (that is, when X2 = 180-2α + β). Θ2 is an incident angle when the light of the path L4 is incident on the lower surface 90a, and has a relationship of θ2 = 90− (X1 + β). In other words, the filter member 90 has θ2 of 90− (X1 + β). ), The transmittance is preferably zero.

  In the above variable, α can be set to 80 °, for example, and may be an angle other than this. Β is a value that varies depending on the material, surface roughness, and the like of the transmission plate 80, and can be set to about 10 °, for example. Further, θ1 can be set to about 75 °, for example. In this case, since X2 is 30 ° and θ2 is 60 °, it is desirable that the filter member 90 has a configuration such that the transmittance is substantially 0 when the incident angle θ2 is 60 °. Further, since the incident angle A1 is 15 °, it is desirable that the filter member 90 is configured to have a transmittance of almost 100% when the incident angle A1 is 15 °.

  1 and 3 is a cut surface obtained by cutting the laser radar device 1 along a plane passing through the central axis 42a and passing through the center P2 of the light receiving surface 20a. In FIG. When the laser beam is irradiated from the concave mirror 41 to the external space along the cut surface, it extends upward through the incident position P3 of the transmission plate inner surface 80a of the laser beam and the front end 90b of the filter member 90 on the cut surface. A virtual first extension line B1 is set. In addition, the laser beam L1 is incident on the inner surface 80a of the transmission plate when irradiated from the concave mirror 41 along the cut surface, and the rear end 90c of the filter member 90 on the cut surface. An imaginary second extension line B2 is set. When such a virtual first extension line B1 and second extension line B2 are set, the light receiving surface 20a of the photodiode 20 is deviated from the first extension line B1 in the region below the first extension line B1. It is the structure arrange | positioned in the position and the position which remove | deviated from 2nd extension line B2 in the area | region above 2nd extension line B2. That is, in the region between the first extension line B1 and the second extension line B2, the light receiving surface 20a is arranged so as not to reach the first extension line B1 and the second extension line B2.

  Further, the filter member 90 is on the path L3 of the specular reflection light when a part of the laser light L1 irradiated forward from the concave mirror 41 along the cut surface (FIG. 3 and the like) is specularly reflected by the transmission plate 80. Is arranged. Further, in the cut surface shown in FIG. 3, the front end portion 90b of the filter member 90 is disposed so as to be located at a part of the path of the laser beam L1 guided in the vertical direction (Y-axis direction) by the above-described laser beam generating means. Has been. “The front end 90b of the filter member 90 is located at a part of the path of the laser light L1” means that a part of the laser light L1 emitted from the laser diode 10 enters the front end of the filter member 90 and is transmitted therethrough. In addition, this means a positional relationship in which other portions pass so as not to enter the front end portion of the filter member 90. The configuration is not limited to such a configuration, and almost all of the laser light L1 emitted from the laser diode 10 may enter the vicinity of the front end portion of the filter member 90 and pass therethrough.

(Main effects of the first embodiment)
In the above configuration, the inner surface (laser light incident surface) of the laser light incident portion of the transmission plate 80 is disposed so as to be inclined with respect to the central axis 42a and directed upward, so that the laser light L1 from the concave mirror 41 is provided. When a part of the light is reflected by the transmission plate 80 and disturbing light is generated, the disturbing light is directed obliquely upward. In such a configuration, it is difficult for disturbance light generated by reflection from the transmission plate 80 to directly enter the concave mirror 41. However, disturbance generated by the transmission plate 80 when laser light is irradiated from the concave mirror 41 to the front side. There is a concern that the light may be received by the photodiode 20 on the rear side and the diagonally upper side. However, in the present invention, the filter member 90 is disposed on the front side and the lower side of the light receiving surface 20a of the photodiode 20, and the filter member 90 transmits light that has a smaller angle with the lower surface 90a of the filter member 90. In addition, it is configured so as to suppress the transmission of disturbance light in the oblique direction from the transmission plate 80 toward the photodiode 20 side, so that the disturbance light is transmitted through the filter member 90 and the photodiode. Therefore, it is possible to reliably prevent the light from traveling to the side 20, and it becomes difficult for ambient light to enter the photodiode 20.

  On the other hand, since the filter member 90 is configured to transmit light in the vertical direction (Y-axis direction), regular reflected light guided upward by the concave mirror 41 (reflected light from an object in the external space). Is difficult to be suppressed when passing through the filter member 90, and can be more reliably guided to the photodiode 20 by suppressing attenuation in the light receiving path in the apparatus. In particular, among the reflected light that enters the filter member 90 from the concave mirror 41, the component having the largest incident angle (the smallest angle formed with the lower surface 90a) is also substantially transmitted, so that the light receiving sensitivity is lowered. Can be maintained.

  Further, since the filter member 90 can be arranged on the light receiving path from the concave mirror 41, it is not necessary to dare to place the filter member 90 away from the light receiving path, and the arrangement space of the filter member 90 is reduced to the light receiving path. This is very advantageous for downsizing. In particular, in the configuration in which the photodiode 20 is arranged on the side of the reflection mirror 30, it is desirable to make the filter members 90 close to the reflection mirror 30 as close as possible in order to reduce the size. Therefore, it is difficult to dispose the filter member 90. In this regard, in the present invention, the filter member 90 can be disposed on the light receiving path without significantly reducing the light receiving sensitivity, which is extremely advantageous in terms of downsizing.

  Further, according to the above configuration, the light receiving surface 20a of the photodiode 20 from the transmission plate 80 in the irradiation direction in which the influence of disturbance light is most concerned (that is, when the laser beam is irradiated forward from the concave mirror 41). The disturbance light that goes directly to the light can be reliably suppressed by the filter member 90. Further, even if there is disturbance light that goes in a direction away from the filter member 90, the disturbance light does not directly enter the photodiode 20, so that the influence of the disturbance light on the photodiode 20 is further increased. It becomes easy to suppress.

  Further, the filter member 90 is disposed on the path L3 of the specular reflection light when a part of the laser light L1 irradiated forward from the concave mirror 41 along the cut surface of FIG. Yes. In this configuration, a specular reflection component having a large energy can be reliably suppressed when the irradiation direction is most concerned about the influence of disturbance light (that is, when laser light is irradiated forward from the concave mirror 41). A large shielding action can be produced.

  Further, the front end portion 90b of the filter member 90 is disposed so as to be located at a part of the path of the laser light guided in the vertical direction by the laser light generating means. In this configuration, since the filter member 90 does not intervene in the entire laser light projection path and the entire laser light from the laser light generation means does not enter the filter member 90, the attenuation at the time of light projection caused by the filter member 90 is reduced. Can be suppressed.

  In addition, according to the above configuration, the photodiode 20 can be disposed on the side of the reflecting mirror 30, and the photodiode 20 does not need to be disposed so much in the upper position. If the photodiode 20 is arranged on a lower side in this way, the degree of inclination of disturbance light from the transmission plate 80 toward the photodiode 20 is increased, and the effect of suppressing transmission through the filter member 90 is further increased.

[Second Embodiment]
Next, a second embodiment of the present invention will be described.
FIG. 5 is a cross-sectional view schematically illustrating a part of the laser radar device according to the second embodiment. In the present embodiment, only the shape and the arrangement position of the filter member 90 are different from those of the first embodiment, and other than that is the same as the first embodiment. Therefore, the same points as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and detailed description thereof is omitted.

  As shown in FIG. 5, in the laser radar device 1 according to the second embodiment, the filter member 90 is formed with a through hole 91 communicating in the vertical direction, and laser light generating means (laser diode 10 and lens 60). The laser beam L1 guided in the vertical direction by the laser beam passes through the through hole 91 and is incident on the concave mirror 41.

  In this configuration, since the laser light from the laser light generating means does not pass through the filter member 90, attenuation during light projection caused by the filter member 90 can be more effectively suppressed. Further, the filter member 90 can be arranged evenly around the light projecting path instead of being disposed only on one side (rear side) of the light projecting path.

  In addition, the material itself of the filter member 90 can use the same thing as 1st Embodiment. The filter member 90 has the same function as that of the first embodiment, and transmits light in the vertical direction (Y-axis direction) and light having a small angle with the lower surface 90a of the filter member 90. When the reflected light generated by reflecting the laser beam L1 from the concave mirror 41 by an object in the external space is taken into the concave mirror 41 and guided upward by the concave mirror 41 Further, it is configured to transmit the reflected light directed upward. Further, similarly to the first embodiment, it is configured to suppress transmission of disturbance light in an oblique direction from the transmission plate 80 toward the photodiode 20 side.

[Third embodiment]
Next, a third embodiment of the present invention will be described.
FIG. 6 is a cross-sectional view schematically illustrating a part of the laser radar device according to the third embodiment. In the present embodiment, only the shape and the arrangement position of the filter member 90 are different from those of the first embodiment, and other than that is the same as the first embodiment. Therefore, the same points as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and detailed description thereof is omitted.

  As shown in FIG. 6, in the laser radar device 1 according to the third embodiment, the entire filter member 90 is disposed at a distance from the center axis 42 a to some extent toward the front. In other words, the front end portion 90b of the filter member 90 is disposed so as to deviate rearward from the path of the laser light L1 guided in the vertical direction by the laser light generating means (the laser diode 10 and the lens 60).

  Even in this configuration, since the laser light from the laser light generating means does not pass through the filter member 90, attenuation during light projection caused by the filter member 90 can be more effectively suppressed.

  Even in this configuration, the material of the filter member 90 can be the same as that of the first embodiment. The filter member 90 also has the same function as that of the first embodiment, and transmits light in the vertical direction (Y-axis direction) while reducing the angle formed with the lower surface 90a of the filter member 90. When the reflected light generated by reflecting the laser beam L1 from the concave mirror 41 by an object in the external space is taken into the concave mirror 41 and guided upward by the concave mirror 41 Further, it is configured to transmit the reflected light directed upward. Further, similarly to the first embodiment, it is configured to suppress transmission of disturbance light in an oblique direction from the transmission plate 80 toward the photodiode 20 side.

[Other Embodiments]
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.

  In the above embodiment, the concave mirror 41 whose reflection surface is configured as a concave surface is exemplified as the deflecting unit, but a plane mirror whose reflection surface is configured as a flat surface may be used. In this case, it is desirable to provide a lens for collecting the reflected light from the plane mirror on the light receiving path from the plane mirror to the photodiode 20.

  In the second embodiment, a through hole is formed in the filter member 90 and the laser light L1 passes through the through hole 91. However, the filter member 90 may not be configured as a complete hole. For example, a notch portion that is notched so as to be recessed rearward at the front end portion of the filter member 90 may be provided, and the laser light L1 may pass through the notch portion.

DESCRIPTION OF SYMBOLS 1 ... Laser radar apparatus 3 ... Case 10 ... Laser diode (laser light source, laser beam generation means)
20 ... Photodiode (light receiving sensor)
20a ... Light receiving surface 30 ... Reflecting mirror 32 ... Passing hole 40 ... Rotating reflection device (rotating deflection means)
41 ... deflection unit 50 ... motor (driving means)
60 ... Lens (Laser light generating means)
80: Transmission plate 80a: Inner surface (incident surface)
DESCRIPTION OF SYMBOLS 90 ... Filter member 90a ... Lower surface 91 ... Through-hole A1 ... Virtual line B1 ... First extension line B2 ... Second extension line L3 ... Path of specular reflected light

Claims (6)

A laser light generating means comprising a laser light source for generating laser light, and configured to guide the laser light from the laser light source in a predetermined vertical direction;
A deflection unit configured to be rotatable about a central axis along the vertical direction; and a driving unit that rotationally drives the deflection unit, and the laser beam generation unit rotates the deflection unit and moves the vertical direction. The deflecting unit deflects the laser light guided to the external space around the deflecting unit, and the deflected laser light is reflected by an object existing in the external space to generate reflected light. Rotational deflection means that reflects upward and guides it to the light receiving path,
A light receiving sensor for receiving the reflected light guided to the light receiving path by the deflection unit;
A case in which at least the light receiving sensor and the deflection unit are accommodated, and the laser beam scanning path is blocked by a transmission plate capable of transmitting the laser beam at least in a circumferential direction around the deflection unit; ,
With
The light receiving sensor is disposed above the position where the laser light emitted from the deflection unit is incident on the transmission plate,
The portion of the transmission plate on which the laser light is incident is disposed such that the incident surface of the laser light is inclined with respect to the central axis and faces upward.
The direction of a virtual line orthogonal to the axis of the central axis and passing through the center of the light receiving surface of the light receiving sensor is the front-rear direction, the side facing the light receiving surface of the light receiving sensor is the front side, and the side opposite to the light receiving surface Is a front side and a lower side of the light receiving surface, and a part of the laser light from the deflection unit is reflected by the transmission plate on the light receiving path above the deflection unit. A filter member that suppresses disturbance light generated by
The filter member has an angle dependency that transmits light in the vertical direction and suppresses transmission as light having a smaller angle with the lower surface of the filter member, and is guided upward from the deflection unit. A laser radar device configured to transmit the reflected light and suppress the transmission of the disturbance light in an oblique direction from the transmission plate toward the light receiving sensor. In the cut surface obtained by cutting the laser radar device along a plane passing through the central axis and passing through the center of the light receiving surface,
An imaginary portion extending upward through the incident position of the laser beam on the inner surface of the transmission plate and the front end of the filter member on the cut surface when the external space is irradiated from the deflection unit along the cut surface. Set the first extension line,
An imaginary portion extending upward through the incident position of the laser beam on the inner surface of the transmission plate and the rear end of the filter member on the cut surface when the external space is irradiated along the cut surface from the deflecting unit. When setting a second extension line
The light receiving surface of the light receiving sensor is disposed at a position deviating from the first extension line in a region below the first extension line, and from the second extension line in a region above the second extension line. The laser radar device according to claim 1, wherein the laser radar device is arranged at a position away from the laser radar device.   The filter member is disposed on a path of specular reflection light when a part of laser light irradiated forward from the deflection unit along the cut surface is specularly reflected by the transmission plate. The laser radar device according to claim 2.   The front end portion of the filter member is disposed so as to be located at a part of the path of the laser light guided in the vertical direction by the laser light generating means, or to be disengaged rearward from the path. The laser radar device according to any one of claims 1 to 3, wherein the laser radar device is characterized in that:   The filter member has a through hole or a notch communicating in the vertical direction, and the laser light guided in the vertical direction by the laser light generating means passes through the through hole or the notch and The laser radar device according to any one of claims 1 to 3, wherein the laser radar device is configured to be incident on a deflection unit. In the light receiving path, on the upper side of the deflecting unit, a reflection hole is formed to pass a laser beam guided in the vertical direction by the laser beam generating means, and reflects the reflected light from the deflecting unit backward. Is provided,
The light receiving sensor is provided on the rear side of the reflecting mirror,
The laser radar device according to any one of claims 1 to 5, wherein the filter member is provided at a position between the reflection mirror and the deflection unit.

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