CN117665764A

CN117665764A - Multi-wavelength scanning device, transmitting module and laser radar

Info

Publication number: CN117665764A
Application number: CN202211042629.3A
Authority: CN
Inventors: 周权; 潘政清; 向少卿
Original assignee: Hesai Technology Co Ltd
Current assignee: Hesai Technology Co Ltd
Priority date: 2022-08-29
Filing date: 2022-08-29
Publication date: 2024-03-08

Abstract

A multi-wavelength scanning device, a transmitting module, and a lidar, the scanning device comprising: the first element deflects the first light to form the second light, and the direction of the optical axis of the light path incident to the first element is a first direction; the second element deflects the second light to form an emergent third light, and an included angle between the third light and the first direction is smaller than an included angle between the second light and the first direction; the first element is one of a grating and a prism; the second element is the other of the grating and the prism. The combination of the grating and the prism can realize the functions of scanning and beam expanding at the same time; and the included angle between the third light and the first direction is smaller than the included angle between the second light and the first direction, and the emergent direction of the third light is close to the first direction, so that the light path size can be effectively controlled, and the miniaturization of the laser radar is facilitated.

Description

Multi-wavelength scanning device, transmitting module and laser radar

Technical Field

The invention relates to the field of laser detection, in particular to a multi-wavelength scanning device, a transmitting module and a laser radar.

Background

The laser radar is a commonly used ranging sensor, has the characteristics of long detection distance, high resolution, small environmental interference and the like, and is widely applied to the fields of intelligent robots, unmanned aerial vehicles and the like. The laser radar works on the principle that information such as the distance or speed of a target is estimated by using the time taken for laser light to travel between the radar and the target, or the frequency shift generated by frequency modulated continuous light traveling between the radar and the target.

In order to obtain a larger field of view, lidar is typically scanned using a scanning device. The scanning modes commonly used by the laser radar include mechanical rotation, mirror scanning, optical Phased Array (OPA) scanning, flash scanning and the like.

In addition, another scanning method is wavelength scanning. The scanning device for wavelength scanning uses a first element such as a grating, a prism and the like to separate light generated by a multi-wavelength light source by different angles based on wavelength so as to achieve the scanning effect.

However, the existing scanning device for scanning wavelength often has the problems of large volume and inconvenient assembly.

Disclosure of Invention

The invention solves the problem of how to reduce the assembly difficulty of the scanning device for wavelength scanning.

In order to solve the above problems, the present invention provides a multi-wavelength scanning apparatus, comprising:

the first element deflects the first light to form the second light, and the direction of the optical axis of the light path incident to the first element is a first direction; the second element deflects the second light to form an emergent third light, and an included angle between the third light and the first direction is smaller than an included angle between the second light and the first direction; the first element is one of a grating and a prism; the second element is the other of the grating and the prism.

Optionally, the third light ray with the central wavelength is parallel to the first direction.

Optionally, the second element is a prism, and the first element is a grating.

Optionally, a preset included angle is formed between the third light rays with different wavelengths.

Optionally, the included angles between adjacent third light rays are substantially equal.

Optionally, the method further comprises: a third element located in an optical path between the first element and the second element; the third element reflects the second light to the second element.

Optionally, the angle between the reflecting surface of the third element and the first direction is in the range of 10 ° to 45 °.

Optionally, the third element includes at least one of a mirror, a galvanometer, and a turning mirror.

Optionally, the reflective surface of the third element rotates about a rotation axis.

Optionally, the reflecting surface rotates at a preset first angular velocity to achieve field of view stitching, wherein the first angular velocity is set based on a maximum included angle between the plurality of third light rays.

Optionally, the reflecting surface rotates at a preset second angular velocity to increase the angular resolution, wherein the second angular velocity is set based on an included angle between third light rays of adjacent wavelengths.

Optionally, the method further comprises: and a fourth element disposed in an optical path downstream of the optical path of the second element to reflect the third light, the reflection surface of the fourth element rotating about the rotation axis.

Optionally, the rotation axis of the reflecting surface of the fourth element is parallel to the incident surface of the first element, and the first light is incident to the incident surface of the first element.

Correspondingly, the invention also provides a transmitting module, which comprises:

a multi-wavelength light source adapted to generate light of multiple wavelengths; a collimating optic adapted to transmit light generated by the multi-wavelength light source to form a first light; the scanning device is the scanning device of the invention.

Optionally, the first element deflects the second light rays with different wavelengths formed by the same first light ray, and the second light rays are all located in the first plane; the emission module includes a plurality of multi-wavelength light sources at least partially distributed within the first plane.

Optionally, the multiple multi-wavelength light sources are further distributed in the second plane, and the second plane is perpendicular to the first plane.

Optionally, the multi-wavelength light source includes: a plurality of lasers of different wavelengths, or at least 1 wavelength tunable laser; the detection element comprises a light detector.

Furthermore, the present invention provides a laser radar including:

a multi-wavelength light source adapted to generate light of multiple wavelengths; a collimating optic adapted to transmit light generated by the multi-wavelength light source to form a first light; the scanning device is provided by the invention; the emergent third light is reflected by the object to be detected to form echo light; a detection element adapted to receive the echo light.

Optionally, the laser radar comprises a transceiver; the transceiver device comprises the transmitting module and a receiving module, and the receiving module comprises the detecting element.

Optionally, the method further comprises: and the light splitting element is positioned on the light path between the multi-wavelength light source and the collimating optical device.

Compared with the prior art, the technical scheme of the invention has the following advantages:

in the technical scheme of the invention, the grating and the prism are simultaneously used, wherein the grating has the function of wavelength scanning, the angle of light is changed based on diffraction, and the prism can expand beams and change the angle of the light based on refraction; therefore, the combination of the grating and the prism not only can realize the functions of scanning and beam expanding at the same time, but also can make the light rays deflect at least twice in different directions, so that the included angle between the third light rays and the first direction is smaller than the included angle between the second light rays and the first direction, and the emergent direction of the third light rays is close to the first direction, thereby effectively controlling the light path size and being beneficial to the miniaturization of the laser radar; meanwhile, in the combination of the grating and the prism, the angle distribution of the grating is uneven and is just compensated by the opposite angle distribution uneven of the prism, so that the uniform scanning angle interval can be realized.

Drawings

FIG. 1 is a schematic view of the optical path of a scanning device for wavelength scanning;

FIG. 2 is a schematic diagram of a multi-wavelength scanning device according to an embodiment of the present invention;

FIG. 3 is a schematic view of the optical path of the embodiment of the multi-wavelength scanning device of FIG. 2 at the first element location;

FIG. 4 is a schematic view of the optical path in the second element of the multi-wavelength scanning device sub-embodiment of FIG. 2;

FIG. 5 is a schematic diagram of an optical path of a first light incident on the first element and the second element in the embodiment of the multi-wavelength scanning device shown in FIG. 2;

FIG. 6 is a schematic diagram of a multi-wavelength scanning device according to another embodiment of the present invention;

FIG. 7 is a schematic diagram of a multi-wavelength scanning device according to another embodiment of the present invention;

FIG. 8 is a schematic diagram of a structure of a multi-wavelength scanning device according to another embodiment of the present invention;

FIG. 9 is a schematic diagram of a structure of a multi-wavelength scanning device according to another embodiment of the present invention;

FIG. 10 is a top view of the structure of the embodiment of the multi-wavelength scanning device of FIG. 9;

FIG. 11 is a top view of an embodiment of a transmitter module of the present invention;

FIG. 12 is a schematic top view of a transceiver device according to an embodiment of the present invention;

fig. 13 is a schematic structural view of another embodiment of the lidar of the present invention.

Detailed Description

As known from the background art, the scanning device for scanning wavelength in the prior art has the problem of inconvenient assembly. The reason for the inconvenient assembly of the scanning device combined with the wavelength scanning is now analyzed by the light path structure of the scanning device:

fig. 1 shows a schematic optical path of a scanning device for wavelength scanning.

As shown in fig. 1, the light source 11 is a multi-wavelength light source, that is, the light source 11 can generate light rays with different wavelengths; the first element 12 comprises a grating. Light rays of different wavelengths generated by the light source 11 are incident on the first element 12 at the same incident angle. According to the diffraction equation of the grating, the diffraction angles of the light rays with different wavelengths after passing through the grating are different. Therefore, the light rays with the same angle are emitted from the first element 12 after being deflected by the grating, so as to separate the light rays with different wavelengths, thereby realizing the scanning effect.

Since the diffraction efficiency of the grating-1 order is highest, as shown in fig. 1, the grating-1 order diffraction light is typically used for scanning, i.e., the diffraction light and the incident light are on the same side of the normal. It is not possible for the light deflected by the grating in the first element 12 to be parallel to the incident light, the deflected light being deflected downwards.

In the application of the laser radar, the diffracted light with different wavelengths is distributed in a plane vertical to the horizontal plane, namely, the laser radar scans different vertical angles by diffracting the light with different wavelengths to different angles. Therefore, in order to bring the exit direction of the multibeam diffracted light close to the horizontal plane to achieve scanning of a range of positive and negative angles of the vertical 0 ° and the vertical direction, as shown in fig. 1, a mirror 13 is typically provided in the optical path downstream of the first element 12. However, the included angle between the reflecting surface of the reflecting mirror 13 and the horizontal direction is larger, so that the arrangement of the reflecting mirror 13 increases the dimension of the light path along the vertical direction, so that the height of the laser radar in the vertical direction is increased, and the size of the laser radar is not reduced. In addition, different optical elements on the optical path of the laser radar are arranged on the horizontal planes with different heights, so that the laser radar is inconvenient to install.

In order to solve the technical problem, the present invention provides a multi-wavelength scanning device, including:

In the technical scheme of the invention, the grating and the prism are simultaneously used, wherein the grating has the function of wavelength scanning, and the prism can expand beams; therefore, the combination of the grating and the prism can realize the functions of scanning and beam expanding at the same time, the included angle between the third light and the first direction is smaller than the included angle between the second light and the first direction, the emergent direction of the third light is close to the first direction, the size of a light path can be effectively controlled, and the miniaturization of the laser radar is facilitated.

In order that the above objects, features and advantages of the invention will be readily understood, a more particular description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings.

Referring to fig. 2, a schematic structural diagram of an embodiment of a multi-wavelength scanning device according to the present invention is shown.

The scanning device includes: a first element 111, wherein the first element 111 deflects a first light ray 121 to form a second light ray 122, and the direction of an optical axis of an optical path of the first element 111 is a first direction; a second element 112, the second element 112 deflects the second light 122 to form an outgoing third light 123, and an angle between the third light 123 and the first direction is smaller than an angle between the second light 122 and the first direction; the first element 111 is one of a grating and a prism; the second element 112 is the other of a grating and a prism.

The first element 111 receives and deflects the first light 121 to form a second light 122; the second element 112 receives and deflects the second light ray 122 to form a third light ray 123.

In some embodiments of the present invention, as shown in fig. 2, the first element 111 is a grating, and the second element 112 is a prism. Therefore, after receiving the first light ray 121, the first element 111 deflects the first light ray 121 with different wavelengths to different angles based on the grating diffraction principle to form a second light ray 122 with different propagation directions; the second element 112 receives the second light ray 122 and deflects the second light ray 122 based on the principle of refraction to form a third light ray 123.

It should be noted that, the first light ray 121 includes a plurality of wavelengths. The first light rays 121 of different wavelengths are therefore deflected by different angles, thereby forming second light rays 122 having different propagation directions.

Specifically, as shown in fig. 3, at the position of the first element 111, according to the grating equation:

d(sinθ _i +sinθ _d1 )＝mλ (1)

wherein d is the grating period, θ _i And theta _d1 The incidence angle and diffraction angle of the beam on the grating, m is the diffraction order and λ is the wavelength, respectively. The grating-1 order diffraction efficiency is usually the highest, i.e. taking m= -1, "-" indicates that the incident light is on the same side of normal as the diffracted light. Therefore, after light of different wavelengths is diffracted by the grating, diffraction angles of the diffracted light are different, and the diffracted light is deflected downward.

As shown in fig. 4, in the second element 112, the prism may deflect the outgoing light in the opposite direction with respect to the incoming light with respect to the horizontal direction according to the refraction principle of the prism. The incident angle α is inversely related to the exit angle γ, and in combination with fig. 2, the incident angles of light beams of different wavelengths to the prism from top to bottom are sequentially reduced, and the exit angle γ is sequentially increased. The beams with the central wavelength can be emitted horizontally through position and angle design, and the beams with other wavelengths are emitted to positive angles and negative angles in the vertical direction respectively, so that the scanning in the vertical direction is realized.

Further, referring to fig. 5 in combination, for the first light ray of the same propagation path, sin θ _i For the constant value, taking the differential according to the grating equation (1) can obtain:

as can be derived from equation (1) and equation (2), for a predetermined angle θ _i The larger the wavelength lambda of the first light ray of the incident grating is, the diffraction angle theta _d1 The larger the first light of the same wavelength difference dλ, but the larger the wavelength, the more the second light formed by diffraction of the first light of adjacent two wavelengths is separated by an angle dθ _d1 The larger. It can be seen that the first light beams with multiple wavelengths are incident on the grating at the same predetermined angle, and the light beams are unevenly separated by the grating, i.e. as shown in fig. 5, the included angle Δθ of the two second light beams 322 with larger wavelengths _d1 ' an included angle delta theta greater than the two second light rays 322 with smaller wavelength _d1 。

With continued reference to fig. 5, when the second light enters the prism, the incident angle and refraction angle conform to fresnel's law as follows:

sinθ _i2 ＝n·sinθ _d2 (3)

wherein θ _i2 Is the incident angle sin theta _d2 N is the refractive index of the prism for the angle of refraction.

Taking the derivative of equation (3) yields:

cosθ _i2 ·dθ _i2 ＝n·cosθ _d2 dθ _d2 (4)

derivation of equation (4) to obtain dθ _d2 /dθ _i2 As a monotonically decreasing function, i.e. with dθ _i2 Increase, dθ _d2 And (3) reducing.

When the wavelength of the first light increases, the second light formed by diffraction of the first light with adjacent two wavelengths is separated by an angle dθ _d1 Increasing; dθ _d1 Increased simultaneous dθ _i2 Increase d theta _d2 And thus the angle at which third light rays of adjacent wavelengths are separated after passing through the prism is reduced. As shown in fig. 5, although the second light ray Δθ _d1 ’＞Δθ _d1 The included angle delta theta between the third light rays with different wavelengths after being refracted by the prism _d2 ’＝Δθ _d2 . It can be seen that the grating andin the combination of the prisms, the angle distribution of the grating is uneven and is just compensated by the opposite angle distribution uneven of the prism, so that the included angles between the third light rays formed by the first light rays with uniform wavelength intervals are basically the same, and the uniform scanning angle interval can be realized.

In some embodiments of the present invention, the second light 122 is directly projected onto the second element 112, that is, the first element 111 deflects the first light 121 such that the formed second light 122 propagates toward the second element 112 and is directly projected onto the second element 112, and no other optical element is present in the optical path between the second element 112 and the first element 111.

In the embodiment shown in fig. 2, the first element 111 is a grating, so that after the first light 121 with different wavelengths is split by the first element 111, a second light 122 with different propagation directions is formed; the second light rays 122 with different wavelengths and different propagation directions are obliquely incident to the second element 112, so that the emergent directions of the third light rays 123 formed by refracting the second light rays 122 with different wavelengths are also different, thereby realizing scanning with different view field directions.

The surface of the second element 112 that receives the second light ray 122 is an incident surface of the second element 112, and the surface of the third light ray 123 that exits the second element 112 is an exit surface of the second element 112. In some practical examples of the present invention, an intersection line of the incident surface of the second element 112 and the exit surface of the second element 112 is perpendicular to the first direction. By making the intersection line perpendicular to the first direction, the incident surface of the first light ray 121 and the incident surface of the second light ray 122 can be made coplanar, so that the second light ray 122 with different wavelengths and the third light ray 123 with different wavelengths can be made coplanar.

In some practical examples of the present invention, as shown in fig. 2 and 4, in the incident plane of the second element 112, the incident plane of the second element 112 intersects the exit plane of the second element 112 on a side far from the first element 111, so that the second light ray 122 deflects toward the first direction when transmitting the second element 112, and the formed third light ray 123 forms a smaller included angle with the first direction.

In some embodiments of the present invention, the third light ray 123 with a central wavelength is parallel to the first direction. The third light ray 123 with the central wavelength is parallel to the first direction by an angle design, i.e. a preset positional relationship between the first element 111 and the second element 112.

In some embodiments of the present invention, the third light rays 123 with different wavelengths form a predetermined included angle. The third light rays 123 with different wavelengths form a preset included angle through angle design, i.e. according to the grating equation and the material and shape of the second element 112.

In some embodiments of the present invention, the angles between adjacent third light rays 123 are substantially equal, thereby achieving uniform scan angle spacing. Specifically, the included angles between any two adjacent third light rays 123 are all equal preset angles, so that the scanning angle intervals of the laser radar are uniform, certain errors exist in practical application, and the difference between the included angles between the adjacent third light rays 123 and the preset angles is not more than 10% of the preset angles, and is regarded as basically equal.

Specifically, in the embodiment shown in fig. 2, the collimated first light ray 121 is incident to the first element 111 along a horizontal direction, that is, the first direction is a horizontal direction; the first element 111 separates the first light rays 121 with different wavelengths to form a second light ray 122 with different propagation directions deviating from the first direction; the second element 112 deflects the second light ray 122 of a different wavelength in opposite directions, so that the propagation direction of the formed third light ray 123 is closer to the horizontal direction.

Moreover, the distance between the first element 111 and the second element 112 is smaller and is basically at the same height, so that the cooperation of the grating and the prism can realize wavelength scanning without excessively increasing the height and volume of the scanning device, thereby being beneficial to miniaturization of the laser radar.

In addition, based on refraction principle, in the deflection of prism to light, the emergent direction and the incident direction of light are different, can arouse the change of beam width simultaneously, consequently when the grating carries out the beam split, cooperate the deflection effect of prism, can play the effect of expanding the beam to the light, can increase laser radar's bore, increase laser radar can receive the light energy, promote the remote measurement ability.

In the foregoing embodiment, the first element 111 is a grating, and the second element 112 is a prism. But this arrangement is merely an example. In other embodiments of the present invention, the first element 111 may be a prism, and the second element 112 may be a grating, so that the same technical effect can be achieved.

Referring to fig. 6, a schematic structural diagram of another embodiment of the multi-wavelength scanning device of the present invention is shown.

The same points as the foregoing embodiments are not repeated here. Unlike the previous embodiments, in some embodiments of the present invention, the scanning device further includes: a third element 213, the third element 213 being located in the optical path between the first element 211 and the second element 212; the third element 213 reflects the second light ray 222 to the second element 212. The third element 213 reflects the second light beam 222 to the second element 212, so that the optical path can be further folded, and the optical path volume can be further reduced, which is beneficial to miniaturization of the laser radar.

In some embodiments of the present invention, an angle between a line between the geometric center of the third element 213 and the geometric center of the first element 211 and the first direction is greater than 45 °, that is, the projection of the first element 211 and the projection of the third element 213 are close to each other along the first direction, which is advantageous for miniaturization of the device.

In some embodiments of the present invention, the angle between the reflecting surface of the third element 213 and the first direction is in the range of 10 ° to 45 °. Limiting the angle between the third element 213 and the first direction can reduce the projection area of the third element 213 in the vertical plane of the first direction, thereby being beneficial to compressing the optical path size and miniaturizing the laser radar. Specifically, as shown in fig. 6, in some embodiments of the present invention, the third element 213 is a mirror, and a reflecting surface of the mirror faces the first element 211 and the second element 212.

In other embodiments of the present invention, as shown in fig. 7, the reflective surface of the third element 213 rotates about a rotation axis. The reflector rotates around the rotating shaft, the rotating shaft is perpendicular to the first direction, and the reflecting angle of the second light ray is changed along with the change of the rotating angle of the reflector around the shaft, so that the scanning view field range can be enlarged, or the scanning resolution can be improved. Specifically, the third element 213 may include at least one of a galvanometer, a turning mirror, and a swinging mirror.

Referring to fig. 7 in combination, the reflecting surface 213a rotates at a preset first angular velocity to achieve field of view stitching, where the first angular velocity is set based on an angle between the third light ray 223 with the largest wavelength and the third light ray 223 with the smallest wavelength. The solid line in the third light ray in fig. 7 represents the third light ray formed by the reflection surface 213a reflecting the second light ray of different wavelength at the first angle, and the broken line in the third light ray represents the third light ray formed by the reflection surface 213a reflecting the second light ray at the second angle. It can be seen that the rotation speed of the reflecting surface 213a is relatively fast, so that the fields of view of the second light rays 222 reflected by the reflecting surface 213a in different emission periods are spliced, thereby expanding the scanning field of view range.

Referring to fig. 8 in combination, the reflecting surface 213b rotates at a preset second angular velocity to increase the angular resolution, wherein the second angular velocity is set based on the included angle between the third light rays 223 of adjacent wavelengths. The solid line in the third light ray in fig. 8 represents the third light ray formed by the reflection surface 213b reflecting the second light ray of a different wavelength at the first angle, and the broken line in the third light ray represents the third light ray formed by the reflection surface 213a reflecting the second light ray at the second angle. It can be seen that the rotation speed of the reflecting surface 213b is slower, and the fields of view corresponding to the second light rays 222 reflected by the reflecting surface 213b in different emission periods are staggered, so that the angular resolution of scanning can be improved.

Referring to fig. 9, a schematic structural view (side view) of a further embodiment of the multi-wavelength scanning device of the present invention is shown. Fig. 10 shows a structural top view of the embodiment of the multi-wavelength scanning device shown in fig. 9.

The same points as the foregoing embodiments are not repeated here. Unlike the previous embodiments, in some embodiments of the present invention, the scanning device further includes: a fourth element 314, the fourth element 314 being located downstream of the second element 312 in the optical path to reflect the third light ray 323, the reflecting surface of the fourth element 314 rotating about a rotation axis.

As shown in fig. 9, the reflecting surface of the fourth element 314 has an included angle with the plane on which the third light ray 323 is distributed, and the rotation axis is parallel to the incident surface of the first light ray 321 on the first element 311, so that the third light ray 323 reflected by the fourth element 314 rotates in a plane perpendicular to the incident surface of the first light ray 321 on the first element 311 along with the rotation of the reflecting surface of the fourth element 314.

In some embodiments of the present invention, as shown in fig. 9 and 10, the rotation axis is perpendicular to the horizontal plane, so that the third light 323 reflected by the fourth element 314 is deflected in the horizontal plane as the reflection surface of the fourth element 314 rotates, thereby realizing scanning in the horizontal direction.

Correspondingly, the invention further provides a transmitting module.

Referring to fig. 9, a schematic diagram of the structure of an embodiment of the transmitting module of the present invention is shown.

The transmitting module includes: a multi-wavelength light source 315, the multi-wavelength light source 315 being adapted to generate light of multiple wavelengths; a collimating optic 316, said collimating optic 316 being adapted to transmit light generated by said multi-wavelength light source 315 to form a first light ray 321; a scanning device 310, wherein the scanning device 310 is a transmitting module of the present invention.

The multi-wavelength light source 315 is configured to generate light for detection.

The light generated by the multi-wavelength light source 315 is multi-wavelength light, that is, the light generated by the multi-wavelength light source 315 includes a plurality of wavelengths. Specifically, in some embodiments, the multi-wavelength light source 315 includes: a plurality of lasers of different wavelengths, or at least 1 wavelength tunable laser. Wherein the wavelength tunable laser may include, but is not limited to, dye lasers, solid state lasers, excimer lasers, and the like.

Specifically, the light generated by the multi-wavelength light source 315 is transmitted to form a first light 321.

The collimating optics 316 are adapted to collimate the light generated by the multi-wavelength light source 315.

Specifically, the collimating optical device 316 includes: at least one collimating lens.

The scanning device 310 is adapted to change the propagation direction of the outgoing light rays to effect scanning.

The scanning device 310 is the scanning device 310 of the present invention, and the specific technical scheme of the scanning device 310 refers to the foregoing embodiment of the scanning device 310, and the disclosure is not repeated herein.

The multi-wavelength light source 315 sequentially outputs light rays with different wavelengths, and the light rays with different wavelengths are respectively deflected to different angles in the vertical direction by the scanning device 310, so that sequential scanning with a plurality of vertical angles is realized.

Specifically, the second light rays 322 formed by deflecting the same first light ray 321 by the first element 311 and having different wavelengths are all located in the first plane; in some embodiments of the present invention, the emission module includes a plurality of multi-wavelength light sources 315, where the plurality of multi-wavelength light sources 315 are at least partially distributed in the first plane, that is, the plurality of multi-wavelength light sources 315 are arranged coplanar. A plurality of multi-wavelength light sources 315 are arranged in a coplanar manner in the first plane, and light rays generated by each multi-wavelength light source 315 also emit in different directions in the same plane; further, by scanning the wavelengths of the scanning device 310, the light rays with different wavelengths are separated in the same plane, and under the condition that the number of the wavelengths is unchanged, the combination of the multiple multi-wavelength light sources 315 and the scanning device 310 of the present invention can multiply increase the number of the scanning lines under the condition that the number of the wavelengths is unchanged, and can greatly improve the scanning field range and/or the scanning field resolution.

In the embodiment shown in fig. 9, the first plane is vertical to the horizontal plane, that is, the second light ray 322 formed by the same first light ray 321 and having a different wavelength is separated in the direction of the vertical horizontal plane; therefore, the multiple multi-wavelength light sources 315 are at least partially distributed and separated in a plane vertical to the horizontal plane, and the light rays generated by different multi-wavelength light sources 315 in the plane are separated in the plane vertical to the horizontal plane and are emitted towards different directions; the scanning device 310 scans the wavelength of light generated by the different multi-wavelength light sources 315, and the light of different wavelengths generated by the same light source is further separated in the vertical direction to scan the vertical direction with a larger field of view range and/or field of view resolution.

Referring to fig. 11, a structural top view of another embodiment of the transmitting module of the present invention is shown.

The same points as the foregoing embodiments are not repeated here. Unlike the previous embodiments, in some embodiments of the present invention, the plurality of multi-wavelength light sources 415 are also distributed in the second plane, which is perpendicular to the first plane.

As shown in fig. 11, the second plane is perpendicular to the first plane where the second light beams with different wavelengths formed by the same first light beam 421 are located together, and the multi-wavelength light sources 415 in different second planes are located at different positions on the focal plane of the collimating lens assembly 416, so that the first light beam 421 collimated by the collimating lens assembly 416 exits in parallel to the first direction, and the third light beam 423 formed by the transmission of the scanning device 410 exits in different directions in the second plane, thereby realizing scanning in the second plane.

Specifically, the second plane is a horizontal plane, so that portions of the multiple wavelength light sources 415 are distributed in the same horizontal plane, and the multiple wavelength light sources 415 in the same horizontal plane are located at different positions of the focal plane of the collimating lens assembly 416, so that the formed third light beam 423 is emitted in different directions in the horizontal plane, and further horizontal scanning is achieved.

It should be noted that, in other embodiments of the present invention, the multi-wavelength light source may be a two-dimensional array to directly implement a wide-range two-dimensional scanning, that is, the wide-range two-dimensional scanning may be directly implemented without a fourth element.

In addition, the invention also provides a laser radar. The laser radar includes: the transmitting module is provided by the invention; the emergent third light is reflected by the object to be detected to form echo light; a detection element adapted to receive the echo light.

The emitting module is suitable for emitting light for detection. The transmitting module is the transmitting module of the present invention, so the specific technical scheme of the transmitting module refers to the foregoing embodiment of the transmitting module, and the present invention is not repeated herein.

The detection element is adapted to receive the echo light to obtain point cloud data. In some embodiments of the invention, the lidar comprises a transceiver. The transceiver device comprises the transmitting module and a receiving module, and the receiving module comprises the detecting element. The detection element comprises a light detector. Wherein the photodetector includes, but is not limited to, at least one of a PIN PD, APD, siPM, SPAD, CMOS, CCD.

As shown in fig. 12, in other embodiments of the present invention, the transceiver 510 includes a plurality of packaging structures 520, and each packaging structure 520 includes: a transmitting unit 521 having a multi-wavelength light source and a receiving unit 522 having a detecting element. By integrating the transmitting unit 521 and the receiving unit 522 through the package structure 520, the same package structure 520 can realize transmitting and receiving at the same time, thereby forming a coaxial optical path.

It should be noted that, in other embodiments of the present invention, the package structure 520 may also be a transceiver waveguide, that is, the corresponding transmitting unit 521 and the receiving unit 522 are both coupled to the same transceiver waveguide, the third light emitted for detection exits from the transceiver waveguide, and the echo light is also coupled and received by the transceiver waveguide. A spectroscopic device connected to the transmitting-receiving waveguide performs spectroscopic of the transmitted light beam and the received light beam.

Referring to fig. 13, a schematic structural view of another embodiment of the lidar of the present invention is shown.

The same points as the foregoing embodiments are not repeated here. Unlike the foregoing embodiments, in some embodiments of the present invention, the lidar further includes: a light splitting element 640, the light splitting element 640 being located on the optical path between the multi-wavelength light source and the collimating optical means.

In some embodiments of the present invention, the lidar is a coaxial optical path lidar. The transmitting module 610 and the receiving module 620 are separated, and the optical paths of the first light and the echo light are separated by the beam splitting element 640, such as a polarization beam splitter. Such a coaxial optical path enables transmit-receive decoupling.

In summary, a grating and a prism are used simultaneously, wherein the grating has the function of wavelength scanning, and the prism can expand beams; therefore, the combination of the grating and the prism not only can realize the functions of scanning and beam expanding at the same time; and the included angle between the third light and the first direction is smaller than the included angle between the second light and the first direction, and the emergent direction of the third light is close to the first direction, so that the light path size can be effectively controlled, and the miniaturization of the laser radar is facilitated.

Although the present invention is disclosed above, the present invention is not limited thereto. Various changes and modifications may be made by one skilled in the art without departing from the spirit and scope of the invention, and the scope of the invention should be assessed accordingly to that of the appended claims.

Claims

1. A multi-wavelength scanning device, comprising:

the first element deflects the first light to form the second light, and the direction of the optical axis of the light path incident to the first element is a first direction;

the second element deflects the second light to form an emergent third light, and an included angle between the third light and the first direction is smaller than an included angle between the second light and the first direction;

the first element is one of a grating and a prism; the second element is the other of the grating and the prism.

2. The scanning device of claim 1, wherein a third ray of center wavelength is parallel to said first direction.

3. The scanning device of claim 1, wherein said second element is a prism and said first element is a grating.

4. A scanning device as claimed in claim 1 or 3, characterized in that the third light rays of different wavelengths form a predetermined angle.

5. The scanning device of claim 4, wherein the included angles between adjacent third light rays are substantially equal.

6. The scanning device of claim 1, further comprising: a third element located in an optical path between the first element and the second element;

the third element reflects the second light to the second element.

7. The scanning device of claim 6, wherein the angle of the reflective surface of said third element with respect to said first direction is in the range of 10 ° to 45 °.

8. The scanning device of claim 6, wherein said third element comprises at least one of a mirror, a galvanometer, and a turning mirror.

9. The scanning device of claim 6, wherein the reflective surface of said third element rotates about a rotational axis.

10. The scanning device of claim 9, wherein said reflective surface rotates at a predetermined first angular velocity to achieve field of view stitching, wherein said first angular velocity is set based on a maximum included angle between a plurality of said third rays.

11. The scanning device of claim 10, wherein said reflective surface rotates at a predetermined second angular velocity to increase angular resolution, wherein said second angular velocity is set based on an included angle between third light rays of adjacent wavelengths.

12. The scanning device of claim 1, further comprising: and a fourth element disposed in an optical path downstream of the optical path of the second element to reflect the third light, the reflection surface of the fourth element rotating about the rotation axis.

13. The scanning device according to claim 12, wherein a rotation axis of the reflecting surface of said fourth element is parallel to an incident surface of said first element upon which said first light is incident.

14. A transmit module, comprising:

a multi-wavelength light source adapted to generate light of multiple wavelengths;

a collimating optic adapted to transmit light generated by the multi-wavelength light source to form a first light;

scanning device according to any one of claims 1 to 13.

15. The emissive module of claim 14, wherein the first element deflects a second light ray of a different wavelength from the same first light ray, all lying in a first plane;

the emission module includes a plurality of multi-wavelength light sources at least partially distributed within the first plane.

16. The emissive module of claim 15, wherein the plurality of multi-wavelength light sources are further distributed in a second plane, the second plane perpendicular to the first plane.

17. The emissive module of claim 14, wherein the multi-wavelength light source comprises: a plurality of lasers of different wavelengths, or at least 1 wavelength tunable laser.

18. A laser radar is characterized in that,

a transmitting module as claimed in any one of claims 14 to 17;

the emergent third light is reflected by the object to be detected to form echo light;

a detection element adapted to receive the echo light.

19. The lidar of claim 18, wherein the lidar comprises a transceiver device;

the transceiver device comprises the transmitting module and a receiving module, and the receiving module comprises the detecting element.

20. The lidar of claim 19, further comprising: and the light splitting element is positioned on the light path between the multi-wavelength light source and the collimating optical device.