CN210090676U

CN210090676U - Scanning mirror and laser radar

Info

Publication number: CN210090676U
Application number: CN201822012128.6U
Authority: CN
Inventors: 陈泽
Original assignee: Beijing Awakening Technology Co Ltd
Current assignee: Beijing Awakening Technology Co Ltd
Priority date: 2018-12-03
Filing date: 2018-12-03
Publication date: 2020-02-18
Anticipated expiration: 2028-12-03

Abstract

The utility model provides a scanning mirror, reflector and shell fragment including the reflected beam. The elastic piece includes a frame portion and a vibrating portion elastically connected to the frame portion via a connecting portion and attached to the mirror. The oscillating portion reciprocates the mirror about a transverse axis relative to the frame portion, thereby scanning the light beam in a direction perpendicular to the transverse axis. Based on the technical scheme, the single scanning mirror can be used for reflecting the same light beam at different scanning angles to form a plurality of scanning light beams with different angle orientations, so that the scanning effect similar to that of a multi-line laser radar is achieved, but the cost is obviously reduced. Additionally, the utility model also provides a laser radar including this scanning mirror, it can compromise low cost, small, high performance.

Description

Scanning mirror and laser radar

Technical Field

The present application relates to scanning mirrors, and more particularly to a one-dimensional mechanical galvanometer for scanning a beam, and a lidar incorporating such a galvanometer.

Background

The vehicle may be configured to operate in an autonomous mode, in which the vehicle navigates through the environment with little or no driver intervention. Such autonomous vehicles may include one or more sensors, such as lidar, configured to detect information about the environment surrounding the vehicle.

The laser radar has a laser and a detector, the detector can detect laser light emitted by the laser and reflected by a reflecting object, and the distance to the reflecting object can be determined by measuring the flight time of the laser light. By scanning a region rapidly and repeatedly with a lidar, continuous real-time information of the distances of all reflecting objects in the region can be obtained. In combination with the distance, laser orientation and measurement time, "point cloud" data reflecting the topography, position and motion of various reflective objects may be generated, and by analyzing the "point cloud" data, autonomous operation of the vehicle may be assisted or achieved.

The prior art provides lidar in a variety of configurations. For example, the solid-state laser radar uses the MEMS two-dimensional scanning mirror to scan laser, which has the advantages of compact structure, fast scanning speed, etc., but is limited by the limitation of semiconductor process, and the cost of the MEMS scanning mirror is very high, which limits the application of the solid-state laser radar. The multi-line laser radar adopts a plurality of lasers which are arranged in a line in the vertical direction, and the plurality of lasers are rotated by the rotating structure to realize scanning in the horizontal direction.

Therefore, it is desirable to provide a new scanning mirror structure for implementing a low-cost, small-volume, high-performance lidar.

Disclosure of Invention

The utility model discloses aim at overcoming prior art's defect, provide a scanning mirror for laser radar of brand-new structure to and including the laser radar of this scanning mirror, compromise low cost, small, high performance.

According to an aspect of the utility model, a scanning mirror is provided, reflector and shell fragment including the reflected beam. The shell fragment includes: a frame portion; and a vibrating portion elastically connected to the frame portion via a connecting portion and attached to the mirror. The oscillating portion reciprocates the mirror about a transverse axis relative to the frame portion, thereby scanning the light beam in a direction perpendicular to the transverse axis. Based on the technical scheme, the single scanning mirror can be used for reflecting the same light beam at different scanning angles to form a plurality of scanning light beams with different angle orientations, so that the scanning effect similar to that of a multi-line laser radar is achieved, but the cost is obviously reduced.

Optionally, the frame portion comprises a first half and a second half symmetrically distributed on both sides of the transverse axis, the vibrating portion and the mirror being located between the first half and the second half; and the connecting part comprises a first connecting part and a second connecting part which are symmetrically distributed at two sides of the longitudinal axis, the longitudinal axis and the transverse axis are vertically crossed, and the vibrating part and the reflecting mirror are positioned between the first connecting part and the second connecting part. Based on the technical scheme, the elastic sheet can have double symmetry, so that the processing and the control are convenient.

Optionally, the first connection portion comprises: a main beam extending from the vibrating portion to an intermediate point along a lateral axis; a first secondary beam extending from the intermediate point to an end point of the first half; a second secondary beam extending from the intermediate point to an end point of the second half, the first secondary beam and the second secondary beam being symmetric about the transverse axis.

Optionally, the first secondary beam extends from a middle point to said end point of the first half via a first leg, a corner and a second leg in that order, wherein the first and second legs are parallel and opposite to each other and form an acute angle with the primary beam. Based on this technical scheme, first auxiliary girder has two segmentation kink, can show the length that prolongs its extension.

Optionally, the first secondary beam extends from the middle point to the end point of the first half through a first leg, a first corner, a second leg, a second corner and a third leg in this order, wherein the first leg, the second leg and the third leg are parallel and opposite to each other and form an acute angle with the primary beam. Based on this technical scheme, first auxiliary girder has the syllogic kink, can show the length that prolongs its extension.

Optionally, the length of the first secondary beam is 3-10 times, preferably 5 times, the straight distance from the middle point to the end point of the first half. Based on this technical scheme, the length extension of first auxiliary beam can reduce the stress concentration on the connecting portion to be convenient for regulate and control the vibration frequency of vibration portion.

Optionally, the mirror has a reflective surface with a circular shape having a diameter greater than 10 mm. Based on the technical scheme, the receiving aperture of the reflecting mirror is obviously larger than that of the MEMS scanning mirror, and the MEMS scanning mirror can be used for long-distance detection.

Optionally, the spring plate is machined from a metal plate. Based on the technical scheme, the processing of the scanning mirror gets rid of the constraint of processing the MEMS scanning mirror by a semiconductor process, and the cost can be obviously reduced.

Optionally, the vibrating portion has a groove extending along the second axis, the groove exposing a back surface of the mirror, the back surface of the mirror receiving the light beam from the measuring light source and reflecting the light beam to the linear detector, the linear detector measuring a rotation angle of the mirror around the transverse axis based on a position of the reflected light beam; the two magnets are symmetrically arranged on the back of the vibration part about the center of the reflector, and the vibration part and the reflector are driven to rotate around the transverse shaft in a reciprocating mode by the two magnets under the action of the electromagnet.

According to the utility model discloses an on the other hand provides a laser radar, include: a laser that emits emission light that generates reflected light at an object in an environment; a detector that detects the reflected light, thereby determining a distance of the object; and a scanning mirror as described above. The scanning mirror reflects the emitted light to the object, wherein a mirror of the scanning mirror rotates about a first axis such that the emitted light scans in a first direction, and an entirety of the scanning mirror rotates about a second axis such that the emitted light scans in a second direction different from the first direction. The utility model discloses a laser radar has the advantage of taking into account low cost, small, high performance.

Other aspects, embodiments, and implementations will become apparent to those of ordinary skill in the art upon reading the following detailed description and by referring appropriately to the accompanying drawings.

Drawings

Fig. 1 shows a block diagram of a lidar according to the present invention;

fig. 2 shows a perspective view of a lidar according to the present invention;

fig. 3 shows a perspective view of the optical path structure of the laser radar according to the present invention;

fig. 4 shows a perspective view of a scanning structure of a lidar in accordance with the present invention;

fig. 5 shows a front view of a galvanometer of a lidar in accordance with the present invention;

fig. 6 shows a rear view of a galvanometer of a lidar in accordance with the present invention;

fig. 7 shows a side view of a galvanometer of a lidar in accordance with the present invention;

fig. 8 shows a front view of a spring plate according to another embodiment of the invention;

fig. 9 shows a rear perspective view of a galvanometer and an electromagnet of a lidar in accordance with the present disclosure;

fig. 10 shows a perspective view of a galvanometer and a position measuring device of a lidar in accordance with the present invention;

fig. 11 shows a perspective view of a lidar according to the present invention and a laser projection surface produced thereby.

Reference numerals:

1 laser 73 linear detector

2 detector 8 second driver

3 galvanometer, scanning mirror 81 stepping motor

31 second measuring module of vibration part 9

32 connecting part 91 code disc

321 main beam 92 encoder

322 first secondary beam X vibration axis, transverse axis

324 second auxiliary beam Y rotating shaft

33 frame portion L1 emits light

331 first half L2 reflects light

332 second half P0 Main Circuit Board

4 optical structure P1 laser circuit board

41 first mirror P2 detector circuit board

42 first lens P3 first measurement circuit board

43 second mirror P4 second measuring Circuit Board

431 slit H0 main support

44 lens H1 first optical mount

45 third mirror H2 second optical mount

5 scanning structure H3 galvanometer support

6 first driver H4 mounting plate

61 electromagnet W casing

62 magnet W1 upper case

63 reflection groove W2 lower casing

7 first measuring module O window

71 light source B substrate equipment

72 steering mirror

M reflector 34 rubber strip

Length of first leg of S-clip L1

Length of Z-bend L2 corner part

Width of Z1 first leg d1 main beam

Width of Z2 second leg d2 secondary beam

The included angle between the first leg part gamma of the first corner part Z3 and the main beam

Z4 second corner X' longitudinal axis

Z5 third leg

Detailed Description

The invention is described below with reference to various embodiments with reference to the accompanying drawings. While this invention is described in terms of the best mode for achieving this invention's objectives, it will be appreciated by those skilled in the art that variations may be accomplished in view of these teachings without deviating from the spirit or scope of the invention.

SUMMARY

Fig. 1 shows a block diagram of a radar according to the present invention, which includes a laser 1 and a detector 2, the laser 1 continuously emits laser light in the form of pulses at a specific frequency (e.g., 125kHz), the wavelength of which is, for example, 905nm, the emitted light is projected to an object (e.g., a building, a pedestrian, a vehicle, a traffic sign, etc.) located at a certain distance, and reflected light is generated, the detector 2 may receive the reflected light, and the distance d of the object from the laser 1 is obtained as C △ t/2(C is the speed of light) by measuring the time difference △ t between the emission of the laser pulse and the reception of the reflected light pulse.

The radar comprises a vibrating mirror 3, wherein the vibrating mirror 3 can receive the emitted light from the laser 1 and reflect the emitted light to project the emitted light into a space to be measured; on the other hand, the galvanometer 3 may receive reflected light from an object in the space to be measured, and reflect it to project to the detector 2. By using the galvanometer 3, a coaxial optical path design can be achieved, i.e. the optical paths of the emitted light and the reflected light substantially coincide in the external optical path portion from the galvanometer 3 to the space to be measured. In the internal optical path portion from the galvanometer 3 to the laser 1 and detector 2, suitable optical structures 4 may be designed to direct the emitted and reflected light to meet specific structural and optical requirements.

The radar further comprises a scanning structure 5 for scanning the emitted light in both vertical and horizontal directions, converting point-like projected light from the laser 1 into planar projected light, so that the object can be detected in a larger spatial range. As shown in fig. 1, the scanning structure 5 includes, in addition to the galvanometer 3, a first driver 6 and a second driver 8. The first driver 6 can drive the galvanometer 3 to reciprocate up and down in a certain angle range around a vibration axis X, and the vibration axis X extends along the horizontal direction, so that one-dimensional scanning light which scans up and down in the vertical direction can be generated; further, the second driver 8 can drive the galvanometer 3 to rotate in a left-right reciprocating manner within a certain angle range around the rotating shaft Y, and the rotating shaft Y extends along the vertical direction, so that the left-right scanning movement in the horizontal direction can be superposed on the vertical direction on the basis of the up-down scanning movement, and the one-dimensional scanning light is further converted into the two-dimensional scanning light.

The scanning structure 5 further comprises a first measuring module 7 and a second measuring module 9 for measuring in real time the deflection angle of the galvanometer 3 during scanning, the first measuring module 7 measures the deflection angle α of the galvanometer 3 with respect to the axis of vibration X_iThe second measuring module 9 measures the deflection angle β of the galvanometer 3 relative to the rotation axis Y_iBy angle combination (α)_i,β_i) The specific orientation of the emitted beam of light emitted by the lidar at a time can be determined, as described above, by measuring at various orientations (α)_i,β_i) The time difference between the emitted light and the received light can be obtained to obtain various orientations (α)_i,β_i) Distance d of lower object_iThereby, a point cloud (α) representing three-dimensional environment information within the field of view of the lidar can be obtained_i,β_i,d_i). A processor may receive the point cloud, analyze and process it to perform a specific function. For example, in the case of applying a laser radar to an unmanned vehicle, the onboard computer may receive and analyze point cloud data from the laser radar to obtain the conditions of objects around the vehicle, thereby generating a specific control strategy to control the vehicle to perform functions such as steering, speed changing, start and stop, and the like, thereby achieving intelligent driving without driver intervention.

An embodiment of the lidar according to the present invention is described in detail below with reference to fig. 2 to 11.

Optical structure

Lidar comprises an optical structure for guiding the emitted and reflected light inside the radar apparatus. Fig. 3 shows the main components of the optical structure, and for clarity, fig. 3 omits components other than the optical structure compared to the general view of fig. 2. The laser 1 is electrically connected to a laser circuit board P1, and the circuitry carried on the laser circuit board P1 is adapted to drive the laser 1. The probe 2 is electrically connected to a probe circuit board P2, and the circuitry carried on the probe circuit board P2 is adapted to receive and transmit the output signal from the probe 2. The laser circuit board P1 and the detector circuit board P2 are both disposed parallel to each other and are vertically terminated on the same side to a main circuit board P0, which may carry electrical components such as a processor, memory, I/O interface, etc. on the main circuit board P0. The main circuit board P0 may be electrically connected to the laser circuit board P1 and the detector circuit board P2, whereby the processor may control the laser 1 to pulse light and process the output signal from the detector 2 to generate and output point cloud data representing the three-dimensional environmental conditions.

For convenience of description, a coordinate system is defined herein with reference to the position of the circuit board P0, including a vertical direction V, a front-rear direction F, and a lateral direction T, which are perpendicular to each other. The circuit board P0 is arranged in a plane defined by the vertical direction V and the lateral direction T, and the laser circuit board P1 and the probe circuit board P2 extend forward in the front-rear direction F.

As shown in fig. 3, the laser 1 is arranged to emit emission light L1 forward. The first mirror 41 is arranged in front of the laser 1 at an angle of 45 degrees to the emitted light L1, whereby the first mirror 41 directs the emitted light L1 to be deflected by 90 degrees so that it travels upwards in the vertical direction V. The emitted light L1 is transmitted upward through the first lens 42, the second reflecting mirror 43 in order, and then reaches the reflecting surface at the vibrating portion 31 of the galvanometer 3. The second reflecting mirror 43 is provided with a through slit 431 allowing the emitted light L1 to pass through the second reflecting mirror 43 without being reflected. The first lens 42 is disposed between the first mirror 41 and the second mirror 43, and the optical axis of the first lens 42 passes through the slit 431, whereby the emitted light L1 can be condensed and deflected to accurately pass through the slit 431. The deflecting action of the first lens 42 can cancel out the deviation of the emitted light L1 due to the mounting error, thereby reducing the requirement for mounting accuracy and simplifying the mounting process.

The mirror 3 is arranged at an angle, for example at an angle of 45 degrees, to the emitted light L1, so as to guide the emitted light L1 substantially forward into the space to be measured. As will be described in detail later, the emitted light L1 will be scanned in two dimensions with vertical vibration and horizontal rotation of the galvanometer 3. The emitted light L1 is reflected by objects in the environment to produce reflected light L2. The reflected light L2 irradiated on the reflecting surface of the galvanometer 3 is deflected by a certain angle by the galvanometer 3 and irradiated on the reflecting surface (upper surface) of the second reflecting mirror 43 in a substantially vertically downward direction. The second reflecting mirror 43 is at an angle of 45 degrees to the vertical direction V, whereby the second reflecting mirror 43 can guide the reflected light L2 to be transmitted rearward. Since the slit 431 of the second reflecting mirror 43 has a small area, most of the reflected light L2 is reflected. The reflected light L2 travels backward through the second lens 44, the third mirror 45 in order to reach the detector 2. The third mirror 45 is disposed between the circuit boards P1 and P2 and is perpendicular to the second mirror 43, thereby directing the reflected light L2 to continue to deflect and be transmitted upward in the vertical direction V to the detector 2. The second lens 44 is disposed between the second mirror 43 and the third mirror 45, and the second lens 44 may converge the divergently reflected light L2 to the detector 2.

As described above, the first reflecting mirror 41, the first lens 42, the second reflecting mirror 43, the galvanometer 3, the second lens 44, and the third reflecting mirror 45 constitute an optical structure, which can advantageously realize a coaxial optical path and give consideration to the compactness of the structure. Specifically, in the optical path from the second reflecting mirror 43 to the external space via the galvanometer mirror 3, the emitted light L1 and the reflected light L2 are arranged substantially coaxially, which contributes to elimination of optical errors existing in the paraxial optical path, improvement of accuracy of laser ranging, and simplification of the structural design. In addition, the first mirror 41 folds the optical path of the emitted light L1 and the third mirror 45 folds the optical path of the reflected light L2, which can greatly reduce the footprint of the optical structure 4 and allow the laser 1 and the detector 2 to be arranged adjacent to each other for easy electrical connection to the same main circuit board P0.

In addition, referring to fig. 2 and 3 in combination, the first optical support H1 may be used to support the first reflector 41, the first lens 42, the second reflector 43, and the mounting board 11 for mounting the laser 1, and the first optical support H1 cooperates with the first reflector 41, the second reflector 43, and the mounting board 11 to form a hollow enclosure, which effectively reduces the loss of the emitted light L1. Similarly, the second optical bracket H2 can be used to support the second lens 44, the third reflector 45 and the probe circuit board P2 for mounting the probe 2, and the second optical bracket H2 cooperates with the second lens 44, the third reflector 45 and the circuit board P2 to form a hollow closed shell, which effectively reduces the loss of the reflected light L2.

The present invention may employ one or more lasers 1 and detectors 2. The embodiment of fig. 3 shows two lasers 1 and two detectors 2. Two lasers 1 are arranged side by side on the mounting board 11, and their emitted light L1 may form an acute angle in the forward direction. The two emitted lights L1 and their respective reflected lights L2 are transmitted through the above-mentioned optical structure 4, and the two reflected lights L2 finally reach two detectors 2 respectively disposed side by side on the detector circuit board P2. Since the emitted light L1 of the two lasers 1 forms an acute angle, the laser projection planes that they respectively scan will have overlapping portions. By setting the relationship between the acute angle and the horizontal scanning rate of the galvanometer 3, the point clouds generated by the two lasers 1 can be distributed in the overlapping part in a staggered manner, so that the encryption effect is achieved, and the point cloud density is improved. Note that the width of the slit 431 on the second reflecting mirror 43 is set to allow the two emitted lights L1 to pass through simultaneously. Although the illustrated embodiment shows two lasers and two detectors, in the embodiments not shown, three, four or other numbers of lasers and detectors may be used to achieve better encryption effect, and these embodiments not shown all fall into the scope of the present invention.

Scanning structure

Fig. 4 shows a scanning structure 5 of the lidar for scanning a point-like emitted light from the laser 1 into a two-dimensional projection surface, as best shown in fig. 11. The scanning structure 5 includes a galvanometer 3 as a scanning mirror which is rotated in two directions simultaneously, thereby scanning the laser light irradiated thereon in two directions to form a two-dimensional projection surface.

Fig. 5 to 7 show a front view, a rear view and a side view of the galvanometer 3 in sequence according to one embodiment. As shown in fig. 7, the galvanometer 3 includes a mirror M and a spring S for mounting the mirror 30. Referring to fig. 5, the mirror M may be a glass mirror or other type of mirror having a circular reflective surface, and may have a diameter d0 of 20mm or other suitable dimension. The diameter of the plane of reflection that compares in MEMS galvanometer only has 1 ~ 2mm usually, the utility model discloses a mirror surface area of speculum is bigger, helps guaranteeing the roughness through machining, has the laser receiving bore who shows the increase, can be used to long distance range finding.

Referring to fig. 6 and 7, the mirror M is attached with its back surface to the front surface of the dome S, for example, adhered to the middle portion of the dome S with a glue strip having a certain thickness. The spring S has a substantially square contour with a side length of, for example, 32 mm. In other embodiments, the spring plate S may have other shapes such as a circle, a rectangle, and the like. The spring plate S may be cut from a metal plate, such as titanium alloy, stainless steel, etc., and may have a thickness of 0.8mm, for example. Referring to fig. 6, the spring sheet S may include a vibration portion 31, a connection portion 32, and a frame portion 33. The frame portion 33 includes a first half 331 and a second half 332 symmetrically arranged about the transverse axis X, and a space for accommodating the mirror M and the vibrating portion 31 is enclosed between the first half 331 and the second half 332. The mirror M is bonded with its back surface to the front surface of the vibrating portion 31. The vibrating portion 31 extends to both sides along another axis X 'perpendicular to the X axis, and may be symmetrical about the transverse axis X and the longitudinal axis X', for example.

The connecting portion 32 connects the vibrating portion 31 and the frame portion 33, and supports the vibrating portion 31 to rotate reciprocally about the transverse axis X with respect to the frame portion 33. The spring plate S includes two connecting portions 32, which are symmetrical with respect to the longitudinal axis X' and are located on opposite sides of the vibration portion 31, respectively. Moreover, each connection 32 is also symmetrical about the transverse axis X. Referring to fig. 6, taking the first connecting portion 32 on the left side of the vibrating portion 31 as an example (the following description applies equally to the second connecting portion 32 on the right side of the vibrating portion 31), the connecting portion 32 has three end points: the first end point D1 is connected to the middle point of the left side edge of the vibrating portion 31; the second end point D2 is connected to the end point on the left side of the first half 331, and the third end point D3 is connected to the end point on the left side of the second half 332. The connecting portion 32 includes a main beam 321 extending rightward in the direction of the transverse axis X from a first end point D1 to a midpoint D4 opposite the left edges of the first and

second halves

331, 332. The width d1 of the main beam 321 is constant, for example 1 mm. The joint 32 further comprises two

secondary beams

322 and 323, the first secondary beam 322 extending from an intermediate point D4 to a second end point D2, the second secondary beam 322 extending from an intermediate point D4 to a third end point D3. As shown in fig. 6, two

sub beams

322 and 323 are arranged symmetrically about the transverse axis X, wherein each sub beam has a bend Z. The bent portion Z extends between the frame member 33 and the vibrating portion 31, specifically between the frame member 33 and the mirror M.

Referring to fig. 6, a first sub-beam 322 on the upper side of the main beam 321 is taken as an example (the following description also applies to a second sub-beam 323 on the lower side of the main beam 321). The bent portion Z includes a first leg Z1 and a second leg Z2 parallel to each other, a corner portion Z3 connecting respective distal ends of the first leg Z1 and the second leg Z2, a first leg Z1 connected from one end of a corner portion Z3 to an intermediate point D4, and a second leg Z2 connected from the other end of a corner portion Z3 to a second end point D2. The angle γ of the first leg Z1 relative to the main beam 321 may be 45 degrees. In other embodiments, the angle γ of the first leg Z1 relative to the main beam 321 defines an acute angle, which may be greater or less than 45 °. In addition, the corner portion Z3 may be parallel to the transverse axis X and extend a length L2. Thus, the length L1 of the first leg Z1 is greater than the length of the second leg Z2. As described above, the first sub-beam 322 meanderingly extends from the middle point D4 to the second end point D2 at the first half 331 through the first leg Z1, the corner Z3, and the second leg Z2 in this order. In addition, although the bending portion Z in the example of the spring plate S shown in fig. 6 has two parallel leg portions, it is conceivable for those skilled in the art to include other numbers of even number of parallel leg portions, such as 4 or 6, under the teaching of this example, and these different embodiments all fall within the scope of the present invention. The width d2 of the first secondary beam 322 is constant, for example 1 mm. The width d2 of the first secondary beam 322 may be greater than, equal to, or less than the first width d1 of the primary beam. In addition, as shown, the inboard profile of the first half 331 and the configuration of the first secondary beam 322 are matched, spaced apart so as not to interfere with each other.

As described above, the distance between the middle point D4 and the second end point D2 of the sub-beam 322 of the present invention is significantly longer than the case where the sub-beam extends directly from the middle point D4 to the second end point D2 perpendicular to the transverse axis X, for example, 3 to 10 times, preferably 5 times, the straight distance between the middle point D4 and the second end point D2. Thus, when the same driving torque is applied to the vibrating portion 31, the acting force is dispersed over the longer connecting portion 32, the stress concentration on the connecting portion 32 is significantly reduced, and the service life of the entire galvanometer 3 is improved. In addition, by adjusting parameters such as the length L1 of the first leg portion Z1 of the bent portion Z, the length L2 of the corner portion Z3, and the angle γ between the first leg portion Z1 and the transverse axis X, the resonance frequency of the rotational vibration of the mirror M about the transverse axis X, for example, 600Hz, and a suitable vibration angle range, for example, 5 to 30 °, preferably 10 °, can be adjusted without changing the overall size of the spring plate S.

On the one hand, the vibrating portion 31 of the galvanometer 3 may be vibrated about a vibration axis X (shown in fig. 4) by the driving of the first driver 6, whereby the emitted light may be scanned in the vertical direction within a certain angle range, for example, within a range of 10 to 60 °, preferably 20 °. The first driver 6 may be an electromagnet 61 while a magnet 62 is provided on the back (the opposite side of the reflection surface) of the vibrating portion 31. When an alternating current is applied to the electromagnet 61, a magnetic field having an alternating direction is generated, and the magnet 62 receives an alternating attractive force or repulsive force, thereby driving the vibrating portion 31 and the mirror S bonded thereto to vibrate together around the vibration axis X. By setting the amplitude and frequency of the current in the electromagnet 61, it is possible to realize that the vibrating portion 31 vibrates just at its resonance frequency (e.g., 600Hz), thereby realizing vibration with less energy consumption

Fig. 7 shows a side view of the galvanometer 3, and the adhesive strip 34 may connect the lower surface of the mirror M and the upper surface of the elastic sheet S, specifically the upper surface of the vibrating portion 31, so that the mirror M and the vibrating portion 31 are fixed and synchronously rotate around the horizontal axis X. As shown, the adhesive strip 34 has a thickness such that the lower surface of the mirror M can be spaced apart from the upper surface of the dome S. Thus, when the mirror M is rotated about the lateral axis X, i.e., about the main beam 321, the lower surface of the mirror M does not touch the edge of the main beam 321.

Fig. 8 shows another example of the spring plate S of the galvanometer according to the invention. This example is substantially identical to the structure of the dome S described above with reference to fig. 6, and only the differences will be described below. The spring S shown in fig. 8 is symmetrical about the axes X and X'. In the upper left region, the first secondary beam 322 connects the main beam 321 and the first half 331, in particular the middle point D4 and the end point D2 of the first half 331. The end point D2 is not collinear with the intermediate point D4 along the longitudinal axis X ', but rather is closer to the longitudinal axis X'. The first secondary beam 322 includes a three-section bend Z including a first leg Z1, a second leg Z2, and a third leg Z5 that are parallel to each other, a first corner Z3 connecting the first leg Z1 and the second leg Z2, and a second corner Z4 connecting the second leg Z3 and the third leg Z5. The first leg Z1 is located outboard of the second leg Z2 and the second leg Z2 is located outboard of the third leg Z5. The spacing between the first and second legs Z1 and Z2 is equal to the spacing between the second and third legs Z2 and Z5. The acute angle subtended by the first leg Z1 and the main beam 321 may be greater than 45 °, for example 60 °. According to this example, the extension length of the sub-beam 322 between the connection intermediate point D4 and the end point D2 of the first half 331 is approximately three times the straight distance between the connection intermediate point D4 and the end point D2 of the first half 331, thereby extending the length of the connection portion. In the light of this example, it is conceivable for the person skilled in the art that the bending portion Z may comprise an odd number of parallel legs of other numbers, for example 1, 5, 7, which different embodiments are within the scope of the present invention.

Fig. 9 shows a rear perspective view of the galvanometer 3. Two cylindrical magnets 62 are symmetrically disposed at the back of the vibration part 31, and the mass of the magnets 62 and the distance from the center of the vibration part 31 can be adjusted to achieve resonance of the vibration part 31. The two electromagnets 61 are arranged opposite to each other for generating a symmetrical magnetic field. To induce stable vibration, the two magnets 62 are subjected to magnetic forces of opposite directions and equal magnitude at the same time. For this purpose, it is possible to provide two magnets 62 with opposite magnetic properties, and two electromagnets 61 with the same magnetic properties; alternatively, the two magnets 62 may be arranged to be of the same polarity and the two electromagnets 61 may be of opposite polarity.

On the other hand, the galvanometer 3 is rotatable as a whole about a rotation axis Y (as shown in fig. 4) by the driving of the second driver 8, whereby the emitted light can be scanned in the horizontal direction within an angle range, for example, within an angle range of 20 to 180 °, more preferably 40 to 90 °, more preferably 48 °. The second driver 8 may be a stepping motor 81, and by controlling the driving current, the rotation speed and the rotation direction of the stepping motor 81 can be accurately regulated. The stepping motor 81 is controlled to output reciprocating rotation within a certain angle range. As shown in fig. 4, the electromagnet 61 as the first driver 6 and the galvanometer 3 are mounted on a galvanometer holder H3. An output shaft of the stepping motor 81 is coupled to an upper end of the galvanometer holder H3, thereby driving the galvanometer holder H3 and the galvanometer 3 thereon to rotate together. As a result, the vibrating portion 31 of the galvanometer 3 also reciprocates around the rotation axis Y.

Therefore, the vibrating portion 31 of the galvanometer 3 rotates about the rotation axis Y while vibrating about the vibration axis X, and the vibration axis X and the rotation axis Y intersect perpendicularly at the center of the vibrating portion 31, as shown in fig. 4. In use, the vibration axis X may be arranged to extend in a horizontal direction parallel to the ground, so that the vibrating motion of the galvanometer 3 scans the laser in a vertical direction; meanwhile, the rotation axis Y may be set to extend in the vertical direction perpendicular to the ground, so that the laser is scanned in the horizontal direction by the rotational movement of the galvanometer 3, thereby obtaining two-dimensional scanning light.

As described above, to obtain three-dimensional point cloud data, it is necessary to measure in real time the deflection angle α of the galvanometer 3 with respect to the vibration neutral position and the deflection angle β with respect to the rotation neutral position FIG. 10 shows the first measuring module 7 for measuring the angle α and the second measuring module 9 for measuring the angle β, with other components omitted, the galvanometer 3 in FIG. 10 is in the neutral position of non-vibration and rotation with the angle α at zero and the angle β at zero.

The first measuring module 7 comprises a light source 71 and a linear detector 73, both of which can be arranged on a first measuring circuit board P3, the first measuring circuit board P3 and a main circuit board P0 are electrically connected, the light source 71 emits a light beam forward, which is deflected via a deflecting mirror 72 arranged at an angle of 45 degrees and then propagates downward to the back of the vibrating portion 31, as shown in fig. 9, the back of the vibrating portion 31 is provided with a linear reflecting groove 63, which exposes the back of the mirror M, and two electromagnets 61 are separately arranged, allowing the light beam to reach the reflecting groove 63, whereby the reflecting groove 63 can reflect the light beam to propagate to a receiving area of the linear detector 73, as shown in fig. 9, the linear detector 73 can be a photodiode array having an elongated receiving area, in this configuration, when the vibrating mirror 3 vibrates, the angle between the reflecting groove 63 and the light beam will vary with the vibrating position of the vibrating mirror 3, and accordingly, the light spot of the reflecting groove 63 falling on the linear detector 73 will vary with the vibrating mirror 3, the linear detector 73 can detect the variation of the position of the light spot, and then calculate the angle of the vibrating mirror 3, which will not disturb the measurement of the first measuring module when the vibrating mirror 3 is rotated around the first measuring module P593, which is mounted on the first measuring module P593, the inner cavity, which is mounted on the first measuring module P5910, which is mounted on the first measuring module P593, so that the first measuring module.

The second measuring module 9 includes a code wheel 91 and an encoder 92, the code wheel 91 is fixed to the upper surface of a galvanometer holder H3 (not shown in FIG. 10, see FIG. 2), the code wheel 91 is provided with a plurality of code tracks uniformly distributed in the circumferential direction, the encoder 92 is fixedly disposed with respect to the stepping motor 81 and is carried by a second measuring circuit board P4, and a second measuring circuit board P4 is electrically connected to the main circuit board P0. As shown in FIG. 10, the encoder 92 and the code wheel 91 are disposed in opposition to each other and can detect the presence of the code track facing each other and then calculate the rotational angle of the code wheel 91. since the code wheel 91 and the galvanometer 3 on the galvanometer holder H3 rotate in synchronization, the encoder 92 can detect the rotational angle β of the galvanometer 3 around the rotational axis Y. specifically, as shown in FIG. 10, the code wheel 91 is partially circular in shape and has an extension angle corresponding to the rotational angle range of the stepping motor 81. in addition, the code wheel 91 and the second measuring circuit board P4 are provided.

As described above, in the scanning structure 5 of the present invention, the galvanometer 3 is a one-dimensional mechanical galvanometer, and the galvanometer 3 vibrates under the driving of the electromagnet 61 and rotates under the driving of the stepping motor 81. Thus, scanning over a two-dimensional plane can be achieved with only a single laser 3, with a smaller number of lasers and a significantly lower cost and power consumption than in prior art multi-line radars. In addition, compare the MEMS mirror that shakes among the prior art, the utility model discloses a mechanical type shakes mirror and makes simply, low cost to have and show bigger optical reception area, can simplify optical structure and improve signal strength. Furthermore, compare the two-dimentional mirror that shakes among the prior art, the utility model discloses a mirror that shakes's axis of rotation Y does not set up in the mirror plane that shakes, but sets up along vertical direction V, and under this condition, lidar's horizontal direction scanning is more close to multi-thread radar's horizontal direction scanning, and the point cloud that obtains is the distribution on the horizontal direction, does not have the distortion, changes in the analysis and treatment point cloud, can show the detection precision that improves lidar.

Mounting structure

Referring back to the general perspective view of FIG. 2, the lidar includes a series of mounting structures for mounting various functional components. As shown, main stand H0 extends in a vertical direction, which is an inverted U-shaped frame configuration. The main circuit board P0 is fixed to the main stand H0 by bolts from the rear. The first bracket H1 is fixed to the main bracket H0 by bolts from below and extends forward for supporting the laser mounting board P1, the first mirror 41, the first lens 42, and the second mirror 43, as described above. The second bracket H2 is bolted over the first bracket H1 for supporting the probe mounting plate P1, the second lens 44 and the third mirror 45, as described above. Second stent H2 is located in the intermediate space of main stent H0 and is fixed to main stent H0 by bolts. Thus, main stent H0, first stent H1 and second stent H2 form a triangular stable connection. In addition, a mounting plate H4 is fixed to the main stand H0 by bolts from above, which extends forward perpendicular to the main stand H0, and the stepping motor 81 is mounted to the upper side of the mounting plate H4. The output shaft of the stepper motor passes through the mounting plate H4. In addition, a second measurement circuit board P4 may be mounted to the lower side of the mounting board H4. As shown in fig. 2, the main stand H0, the first stand H1, the second stand H2, and the mounting plate H4 may enclose a space in which the galvanometer stand H3 is disposed and connected to the output shaft of the stepping motor 81 at the upper end. The galvanometer holder H3 is configured to support a plurality of components such as the galvanometer 3, the electromagnet 61, the light source 71 of the first measuring module 7, the steering mirror 72 and the linear detector 73, and the code wheel 81 of the second measuring module 8, which are rotated as a whole by the driving of the stepping motor 81. The arrangement of the mounting structure as described above can satisfy both the requirements of structural stability and volume compactness.

Fig. 11 shows the external appearance of a lidar having a housing W for accommodating the internal structure of the lidar shown in fig. 2, which may be placed into a cavity of the housing W from the rear of the housing W. The casing W comprises an upper casing W1 and a lower casing W2 which can be detached, and radiating fins can be arranged on the upper casing W1 and the lower casing W2 for radiating heat of the laser radar. In addition, the front surface of the lower case W2 is provided with a window O allowing the laser light to pass therethrough without loss. The housing W can protect the laser radar from the external environment and provide a compact and aesthetically pleasing appearance.

Application example

The utility model discloses a laser radar can be arranged in the occasion that the multiple needs know the surrounding environment condition, including but not limited to fields such as unmanned vehicle, unmanned aerial vehicle, satellite. As shown in fig. 11, a laser radar may be fixed to a base device B (e.g., a vehicle, an airplane, etc.), and the laser radar may project a two-dimensional laser projection surface forward. As described above, the laser projection plane is generated by the scanning motion of the laser light from a single laser in both the horizontal and vertical directions. The embodiment of the present invention provides a laser radar, wherein the scanning frequency of the laser radar in the horizontal direction can be 5Hz, the scanning frequency in the vertical direction can be 600Hz, and the emitting frequency of the laser can be 125 KHz. In addition, the horizontal scanning angle (field of view) of the laser radar can be +/-24 degrees, and the angular resolution can be 0.2 degrees; the vertical scan angle may be ± 10 °, and the angular resolution may be 0.2 °. Taking the base device B as a road vehicle as an example, when the two-dimensional laser projection surface shown contacts an object such as a pedestrian, a vehicle ahead, a traffic sign, a building, etc., the laser radar may generate point cloud data related to the object, and a processor integrated in the road vehicle may process the point cloud data to identify information of the type, shape, position, and movement of the object, and further generate a control signal according to the information, control the vehicle to perform corresponding operations such as start-stop, steering, speed change, etc., and/or send a signal to a passenger or a remote server. Thus, it is possible to realize driving assistance or autonomous driving using the laser radar.

While various examples and embodiments have been disclosed, other examples and embodiments will be apparent to those skilled in the art. The various disclosed examples and embodiments are intended to be illustrative, but not limiting, with the true scope and spirit being indicated by the following claims.

Claims

1. A scanning mirror, comprising:

a mirror that reflects the light beam; and

the shell fragment includes:

a frame portion; and

a vibrating portion elastically connected to the frame portion via a connecting portion and attached to the mirror;

wherein the oscillating portion reciprocates the mirror about a transverse axis relative to the frame portion to scan the light beam in a direction perpendicular to the transverse axis.

2. The scanning mirror of claim 1,

the frame part comprises a first half part and a second half part which are symmetrically distributed on two sides of the transverse shaft, and the vibration part and the reflecting mirror are positioned between the first half part and the second half part;

the connecting part comprises a first connecting part and a second connecting part which are symmetrically distributed on two sides of the longitudinal axis, the longitudinal axis and the transverse axis are vertically intersected, and the vibrating part and the reflecting mirror are positioned between the first connecting part and the second connecting part.

3. The scan mirror of claim 2, wherein the first connection comprises:

a main beam extending from the vibrating portion to an intermediate point along a lateral axis;

a first secondary beam extending from the intermediate point to an end point of the first half;

a second secondary beam extending from the intermediate point to an end point of the second half, the first secondary beam and the second secondary beam being symmetric about the transverse axis.

4. The scanning mirror of claim 3,

the first secondary beam extends from a middle point to the end point of the first half through a first leg, a corner and a second leg in this order, wherein the first leg and the second leg are parallel and opposite to each other and form an acute angle with the primary beam.

5. The scanning mirror of claim 3,

the first secondary beam extends from the middle point to the end point of the first half part sequentially through the first leg part, the first corner part, the second leg part, the second corner part and the third leg part, wherein the first leg part, the second leg part and the third leg part are parallel and opposite to each other, and form an acute angle with the main beam.

6. A scanning mirror according to claim 4 or 5, wherein the length of the first secondary beam is 3-10 times the linear distance that the middle point extends to said end point of the first half.

7. A scanning mirror as claimed in claim 1, characterized in that the mirror has a circular reflecting surface with a diameter of more than 10 mm.

8. The scanning mirror according to claim 1, wherein the spring is machined from a sheet of metal.

9. The scanning mirror of claim 1,

the vibrating portion has a groove extending along the second axis, the groove exposing a back surface of the mirror, the back surface of the mirror receiving the light beam from the measuring light source and reflecting the light beam to the linear detector, the linear detector measuring a rotation angle of the mirror around the transverse axis based on a position of the reflected light beam; and is

The two magnets are symmetrically arranged on the back of the vibrating part relative to the circle center of the reflector, and the vibrating part and the reflector are driven to rotate around the transverse shaft in a reciprocating mode under the action of the electromagnet.

10. A lidar, comprising:

a laser that emits emission light that generates reflected light at an object in an environment;

a detector that detects the reflected light, thereby determining a distance of the object;

a scanning mirror that reflects the emitted light to the object according to any one of claims 1 to 9, wherein a mirror of the scanning mirror rotates about a first axis such that the emitted light scans in a first direction, and an entirety of the scanning mirror rotates about a second axis such that the emitted light scans in a second direction different from the first direction.