CN210572749U - Laser radar system - Google Patents
Laser radar system Download PDFInfo
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- CN210572749U CN210572749U CN201921080713.8U CN201921080713U CN210572749U CN 210572749 U CN210572749 U CN 210572749U CN 201921080713 U CN201921080713 U CN 201921080713U CN 210572749 U CN210572749 U CN 210572749U
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Abstract
The utility model discloses a laser radar system, this laser radar system includes: the light emitting unit, the perforated reflector and the MEMS galvanometer are sequentially arranged along a light path; the perforated reflector comprises a reflector body, and an opening is formed in the center of the reflector body; the MEMS galvanometer comprises a reflecting mirror surface, a substrate and a torsion shaft for connecting the reflecting mirror surface and the substrate; and the projection of the opening of the perforated reflector on the MEMS galvanometer along the optical axis direction of the optical path is positioned in the reflector. The embodiment of the utility model provides a technical scheme, reducible interference signal improves the SNR to be favorable to realizing the accurate detection to the target object.
Description
Technical Field
The embodiment of the utility model provides a relate to laser detection technical field, especially relate to a laser radar system.
Background
The radar is one of light detection and measurement systems that detect characteristic quantities such as a position, a velocity, and the like of a target object with a transmission light beam. The working principle of the radar is as follows: the method comprises the steps of transmitting a detection signal (or detection beam) to a target object, comparing a received signal (or target echo, or echo signal, or echo beam) reflected from the target object with the transmission signal, and performing appropriate processing to obtain relevant information of the target object, such as parameters of target distance, azimuth, height, speed, attitude, even shape and the like, so as to detect, track and identify the target object.
The laser radar uses a laser signal as a probe beam. With the development of the laser radar toward miniaturization, the MEMS galvanometer may be used as a mirror. However, when the MEMS galvanometer is used to realize the structure of the laser radar, more stray light is generated, and the signal-to-noise ratio is low, so that accurate detection of a target object cannot be realized.
SUMMERY OF THE UTILITY MODEL
An embodiment of the utility model provides a laser radar system to reduce interference signal, improve the SNR, thereby be favorable to realizing the accurate detection to target object.
An embodiment of the utility model provides a laser radar system, this laser radar system includes: the light emitting unit, the perforated reflector and the MEMS galvanometer are sequentially arranged along a light path;
the perforated reflector comprises a reflector body, and an opening is formed in the center of the reflector body; the MEMS galvanometer comprises a reflecting mirror surface, a substrate and a torsion shaft for connecting the reflecting mirror surface and the substrate;
and the projection of the opening of the perforated reflector on the MEMS galvanometer along the optical axis direction of the optical path is positioned in the reflector.
Further, the lidar system further comprises a collimation unit;
the collimation unit is arranged in a light path between the light emitting unit and the perforated reflector;
the collimating unit is used for collimating the light beam, so that the light spot irradiated to the perforated reflector covers the open hole of the perforated reflector.
Further, the collimation unit comprises a fast axis cylindrical mirror and a slow axis cylindrical mirror;
the fast axis cylindrical mirror is used for adjusting the divergence angle of the light beam in the fast axis direction;
the slow axis cylindrical mirror is used for adjusting the divergence angle of the light beam in the slow axis direction.
Furthermore, the number of the fast axis cylindrical mirrors is at least two, and the number of the slow axis cylindrical mirrors is at least one.
Further, the aperture size A1 of the perforated mirror is smaller than the mirror surface size A3 of the MEMS galvanometer.
Further, the aperture size a1 of the perforated mirror is smaller than the spot size a2 of the impinging perforated mirror.
Further, the size A3 of the reflecting mirror surface of the MEMS galvanometer meets the requirement that A3 is more than or equal to 3.0mm and less than or equal to 4.0 mm;
the size A2 of a light spot irradiated on the perforated reflector meets the requirement that A2 is more than or equal to 2.0mm and less than or equal to 4.0 mm;
the opening size A1 of the perforated reflector meets the condition that A1 is more than or equal to 0.8mm and less than or equal to 1.3 mm.
Further, the laser radar system further comprises a receiving unit;
the receiving unit and the light emitting unit are respectively arranged on two sides of the perforated reflector; the mirror body of the perforated mirror is used for projecting the reflected echo light beam to the receiving unit.
Further, the receiving unit includes a focusing lens and a photoelectric converter;
the focusing lens is used for focusing the echo light beam reflected by the target object to a receiving surface of the photoelectric converter;
the photoelectric converter is used for performing photoelectric conversion on the echo light beam.
Further, an optical axis of the focusing lens is perpendicular to an optical axis of the light beam passing through the perforated mirror.
The embodiment of the utility model provides a laser radar system, through setting up laser radar system and include light emission unit, perforation speculum and MEMS galvanometer that set gradually along the light path; the perforated reflector comprises a reflector body, and an opening is formed in the center of the reflector body; the MEMS galvanometer comprises a reflecting mirror surface, a substrate and a torsion shaft for connecting the reflecting mirror surface and the substrate; the projection of the opening of the perforated reflector on the MEMS galvanometer along the optical axis direction of the optical path is positioned in the reflector, so that the light rays passing through the opening of the perforated reflector are all projected into the reflector of the MEMS galvanometer and are not projected onto the torsion axis. Therefore, interference signals can be prevented from being generated due to interference of the torsion shaft on light, the signal to noise ratio can be improved, and accurate detection of the target object can be realized.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a laser radar system according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of the construction of the perforated mirror of FIG. 1;
fig. 3 is a schematic structural diagram of the MEMS galvanometer of fig. 1.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.
Fig. 1 is a schematic structural diagram of a laser radar system according to an embodiment of the present invention, fig. 2 is a schematic structural diagram of a perforated mirror in fig. 1, and fig. 3 is a schematic structural diagram of a MEMS galvanometer in fig. 1. With reference to fig. 1-3, a lidar system 10 provided by an embodiment of the present invention includes: a light emitting unit 110, a perforated mirror 120 and a MEMS galvanometer 130 sequentially arranged along a light path; the perforated mirror 120 comprises a mirror body 1201, and an opening 1202 is formed in the center of the mirror body 1201; the MEMS galvanometer 130 includes a mirror surface 1301, a substrate 1302, and a torsion axis 1303 connecting the mirror surface 1301 and the substrate 1302; the projection of the opening 1202 of the perforated mirror 120 on the MEMS galvanometer 130 along the optical axis direction of the optical path is located within the mirror surface 1301.
The light source unit 110 may be a laser emitter for generating a laser beam. Illustratively, the laser beam may have a wavelength of 905 nanometers (nm).
Wherein the laser beam exits the aperture 1202 of the perforated mirror 120. The laser beam emitted from the opening 1202 is projected to the MEMS galvanometer 130 and reflected to the target object 20 through the MEMS galvanometer 130, and the target object 20 reflects the laser beam to form an echo beam. The echo beam is transmitted to the MEMS galvanometer 130 and reflected to the perforated mirror 120 by the mirror 1301 of the MEMS galvanometer 130, and the perforated mirror 120 reflects the echo beam, and then the reflected echo beam is received by the receiving unit 150, and then data processing is performed to obtain the related information of the target object 20.
The torsion shaft 1303 may be made of a titanium alloy material, so that the torsion shaft 1303 may reflect light to some extent. In the prior art, when the probe beam or the echo beam is projected to the MEMS galvanometer 130, the mirror surface 1301 as the working surface is reflected, and the torsion axis 1303 also emits the beam, thereby forming a parasitic light interference signal.
In the embodiment of the present invention, by setting the dimension D2 of the opening 1202 of the perforated mirror 120 to be smaller than the dimension D1 of the reflective mirror 1301 of the MEMS galvanometer 130, it can be ensured that the laser beam passing through the opening 1202 is all projected onto the reflective mirror 1301 of the MEMS galvanometer 130, and is not projected onto the torsion axis 1303 located around the reflective mirror 1301, so as to avoid signal interference caused by reflection of the torsion axis 1303 on the laser beam, that is, to ensure that no parasitic light interference signal is generated, thereby improving the signal-to-noise ratio, and realizing accurate detection of the target object 20.
In fig. 2 and 3, only the opening 1202 and the mirror 1301 are circular, and the diameter of the circle represents the size, but does not limit the laser radar system 10 according to the embodiment of the present invention. In other embodiments, the shapes of the opening 1202 and the mirror 1301 can be set according to the actual requirement of the laser radar system 10, and the size of the opening 1202 and the mirror 1301 is the length value of a line segment passing through the center of the opening 1202 or the center of the mirror 1301 in the light beam transmission surface or the light beam reflection surface and respectively cut by the outline thereof, or other definition ways known to those skilled in the art, which is not limited by the embodiment of the present invention.
Next, it should be noted that fig. 3 only exemplarily shows that the number of the torsion shafts 1303 is 4, and in other embodiments, the number of the torsion shafts 1303 may also be set according to the actual requirements of the MEMS mirror 130 and the laser radar system 10, which is not limited in the embodiment of the present invention.
Optionally, with continued reference to fig. 1, lidar system 10 also includes a collimation unit 140; the collimating unit 140 is disposed in the optical path between the light emitting unit 110 and the perforated mirror 120; the collimating unit 140 is used to collimate the light beam such that the spot of light impinging on the perforated mirror 120 covers the aperture 1202 of the perforated mirror 120.
Wherein the collimating unit 140 is used for collimating the laser beam. By arranging the light spot irradiated to the perforated reflector 120 to cover the opening 1202 of the perforated reflector 120, other light rays can be prevented from penetrating through the opening 1202 and irradiating the reflecting mirror surface 1301 of the MEMS galvanometer 130, so that interference of other light rays can be avoided, and the signal to noise ratio can be improved.
Optionally, with continued reference to fig. 1, the collimating unit 140 includes a fast-axis cylindrical mirror 141 and a slow-axis cylindrical mirror 142; the fast axis cylindrical mirror 141 is used for adjusting the divergence angle of the light beam in the fast axis direction; the slow axis cylindrical mirror 142 is used to adjust the divergence angle of the light beam in the slow axis direction.
The two fast axis cylindrical mirrors 141 are used to adjust the divergence angle of the light beam in the fast axis direction, so that the adjusted divergence angle is 3mrad (full angle). The slow axis cylindrical mirror 142 is used to adjust the divergence angle of the light beam in the slow axis direction, so that the adjusted divergence angle is 10mrad (full angle), and the shape of the light spot finally projected onto the perforated mirror 120 is similar to the shape of the projection of the opening 1202 of the perforated mirror 120 on the vertical plane.
Optionally, with continued reference to fig. 1, the number of the fast-axis cylindrical mirrors 141 is at least two, and the number of the slow-axis cylindrical mirrors 142 is at least one, so as to achieve the above-mentioned adjustment of the light beam.
In other embodiments, the type and number of optical elements in collimating unit 140 may also be set according to the actual requirements of laser radar system 10, which is not limited by the embodiments of the present invention.
Optionally, to prevent the beam from impinging on the torsion axis 1303 of the MEMS galvanometer 130, the aperture size a1 (i.e., D2 in fig. 2) of the perforated mirror may be set smaller than the mirror surface size A3 (i.e., D1 in fig. 3) of the MEMS galvanometer; while the aperture size a1 of the perforated mirror is set to be smaller than the spot size a2 of the light striking the perforated mirror.
Optionally, with continued reference to FIGS. 2 and 3, the dimension A3 of the mirror surface 1301 of the MEMS galvanometer 130 satisfies 3.0mm ≦ A3 ≦ 4.0 mm. Correspondingly, the size of the light spot A2 irradiated on the perforated reflector 120 meets the requirement that the size of the light spot A2 is more than or equal to 2.0mm and less than or equal to 4.0 mm; the size A1 of the opening 1202 of the perforated mirror 120 satisfies 0.8mm < A1 < 1.3 mm. It is understood that the spot size a2 and the size a1 of the aperture 1202 of the perforated mirror 120 may increase with the size A3 of the mirror surface 1301 of the MEMS galvanometer 130, and is not limited to the size limitations of the present embodiment.
With this arrangement, it is possible to realize that the size of the opening 1202 of the perforated mirror 120 is smaller than the spot size and smaller than the size of the mirror surface 1301 in the MEMS galvanometer 130, thereby ensuring that the laser beam passing through the opening 1202 is entirely projected onto the mirror surface 1301 of the MEMS galvanometer 130 and not projected onto the torsion axis 1303. Therefore, stray light interference signals can be reduced, the signal to noise ratio is improved, and accurate detection of the target object 20 can be realized.
Optionally, with continued reference to fig. 1, lidar system 10 also includes a receiving unit 150; the receiving unit 150 and the light emitting unit 110 are respectively disposed at two sides of the perforated mirror 120, and the mirror 1201 of the perforated mirror 120 is used for projecting the echo beam formed by being reflected by the target object 20 to the receiving unit 150.
Wherein, the laser beam emitted by the light emitting unit 110 passes through the opening 1202 of the perforated mirror 120 and is projected to the mirror surface 1301 of the MEMS galvanometer 130; the echo beam formed by the reflection of the target object 20 is reflected by the mirror surface 1301 of the MEMS galvanometer 130 and the mirror body 1201 of the perforated mirror 120 in sequence, and then enters the receiving unit 150.
In this manner, the optical paths of the probe beam and the echo beam at least partially overlap, i.e., form a coaxial lidar system, which facilitates reducing the number of optical components in lidar system 10, thereby facilitating the implementation of integrated and miniaturized designs for lidar system 10.
Alternatively, with continued reference to fig. 1, the receiving unit 150 includes a focusing lens 151 and a photoelectric converter 152; the focusing lens 151 is used for focusing the echo light beam reflected by the target object 20 to a receiving surface of the photoelectric converter 152; the photoelectric converter 152 is used to photoelectrically convert the echo light beam.
The focusing lens 151 may be a lens or a lens group, and the photoelectric converter 152 may be an avalanche photodiode; in other embodiments, the receiving unit 150 may also be composed of other types of focusing lenses 151 and photoelectric converters 152 known to those skilled in the art, and may also include other components known to those skilled in the art, which is not limited by the embodiments of the present invention.
Alternatively, with continued reference to FIG. 1, the optical axis of the focusing lens 151 is perpendicular to the optical axis of the light beam passing through the perforated mirror 120.
In this manner, lidar system 10 may be made compact and detection of the echo beam may be facilitated.
In other embodiments, a mirror assembly may also be provided in the optical path of lidar system 10 to achieve compactness of the device configuration of the overall lidar system 10.
The laser radar system 10 provided by the embodiment of the invention does not generate stray light interference and has a higher signal-to-noise ratio; meanwhile, a coaxial structure can be realized, and the photoelectric converter in the receiving unit cannot be damaged.
It should be noted that the foregoing is only a preferred embodiment of the present invention and the technical principles applied. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail with reference to the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the scope of the present invention.
Claims (10)
1. A lidar system, comprising: the light emitting unit, the perforated reflector and the MEMS galvanometer are sequentially arranged along a light path;
the perforated reflector comprises a reflector body, and an opening is formed in the center of the reflector body; the MEMS galvanometer comprises a reflecting mirror surface, a substrate and a torsion shaft for connecting the reflecting mirror surface and the substrate;
and the projection of the opening of the perforated reflector on the MEMS galvanometer along the optical axis direction of the optical path is positioned in the reflector.
2. The lidar system of claim 1, further comprising a collimating unit;
the collimation unit is arranged in a light path between the light emitting unit and the perforated reflector;
the collimating unit is used for collimating the light beam, so that the light spot irradiated to the perforated reflector covers the open hole of the perforated reflector.
3. The lidar system of claim 2, wherein the collimating unit comprises a fast-axis cylindrical mirror and a slow-axis cylindrical mirror;
the fast axis cylindrical mirror is used for adjusting the divergence angle of the light beam in the fast axis direction;
the slow axis cylindrical mirror is used for adjusting the divergence angle of the light beam in the slow axis direction.
4. The lidar system of claim 3, wherein the number of fast-axis cylindrical mirrors is at least two and the number of slow-axis cylindrical mirrors is at least one.
5. The lidar system of claim 2, wherein an aperture dimension a1 of the perforated mirror is less than a mirror surface dimension A3 of the MEMS galvanometer.
6. The lidar system of claim 1 or 5, wherein an aperture size a1 of the perforated mirror is less than a spot size a2 of light impinging on the perforated mirror.
7. The lidar system of claim 6, wherein a dimension A3 of the mirror surface of the MEMS galvanometer satisfies 3.0mm ≦ A3 ≦ 4.0 mm;
the size A2 of a light spot irradiated on the perforated reflector meets the requirement that A2 is more than or equal to 2.0mm and less than or equal to 4.0 mm;
the opening size A1 of the perforated reflector meets the condition that A1 is more than or equal to 0.8mm and less than or equal to 1.3 mm.
8. The lidar system of claim 1, further comprising a receiving unit;
the receiving unit and the light emitting unit are respectively arranged on two sides of the perforated reflector; the mirror body of the perforated mirror is used for projecting the reflected echo light beam to the receiving unit.
9. The lidar system of claim 8, wherein the receiving unit comprises a focusing lens and a photoelectric converter;
the focusing lens is used for focusing the echo light beam reflected by the target object to a receiving surface of the photoelectric converter;
the photoelectric converter is used for performing photoelectric conversion on the echo light beam.
10. The lidar system of claim 9, wherein an optical axis of the focusing lens is perpendicular to an optical axis of the beam of light passing through the perforated mirror.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921080713.8U CN210572749U (en) | 2019-07-10 | 2019-07-10 | Laser radar system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921080713.8U CN210572749U (en) | 2019-07-10 | 2019-07-10 | Laser radar system |
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| Publication Number | Publication Date |
|---|---|
| CN210572749U true CN210572749U (en) | 2020-05-19 |
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| CN201921080713.8U Active CN210572749U (en) | 2019-07-10 | 2019-07-10 | Laser radar system |
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| CN (1) | CN210572749U (en) |
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- 2019-07-10 CN CN201921080713.8U patent/CN210572749U/en active Active
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