WO2020142954A1

WO2020142954A1 - Distance measurement device

Info

Publication number: WO2020142954A1
Application number: PCT/CN2019/071041
Authority: WO
Inventors: 董帅; 洪小平; 黄淮; 刘祥
Original assignee: 深圳市大疆创新科技有限公司
Priority date: 2019-01-09
Filing date: 2019-01-09
Publication date: 2020-07-16
Also published as: CN111670373A

Abstract

A distance measurement device (100), comprising: a light source (103) used for emitting a light beam; and a scanning module (102) used for sequentially changing the light beam emitted by the light source (103) to different propagation directions, and emitting same, so as to form a scanning field of view, the scanning module (102) comprising a rotating first optical element (114) and a rotating second optical element (115), the first optical element (114) and the second optical element (115) rotating in the same direction or in opposite directions. The rotating first optical element (114) and the rotating second optical element (115) are used to achieve dynamic adjustment of the direction of the light beam emitted by the light source (103). Said device has a simple structure, is thus stable and reliable, has a low cost, facilitating large-scale popularization and application; and the space coverage becomes larger and larger over time, and thus the space information becomes more and more detailed.

Description

Distance detection device

Instructions

Technical field

The present invention relates generally to the field of optical detection, and more particularly to a distance detection device.

Background technique

Lidar is a perception system for the outside world. Taking lidar based on the principle of time of flight (TOF) as an example, the lidar emits pulses outwards and receives echoes from external objects. By measuring the delay of the echo, the distance between the object and the lidar in this emission direction can be calculated. By dynamically adjusting the laser emission direction, it is possible to measure the distance information between objects of different orientations and lidar, so as to realize the modeling of three-dimensional space.

In Lidar, the dynamic adjustment of the laser emission direction of the lidar is a key system function, which affects the spatial range that the system can detect (here, the field of view), and the fineness of the spatial information obtained.

Summary of the invention

A series of concepts in simplified form are introduced in the summary of the invention, which will be explained in further detail in the detailed description section. The summary of the present invention does not mean trying to define the key features and necessary technical features of the claimed technical solution, nor does it mean trying to determine the protection scope of the claimed technical solution.

In view of the shortcomings of the prior art, on the one hand, the present invention provides a distance detection device, which is characterized by comprising:

Light source, used to emit light beam;

A scanning module, configured to sequentially change the light beams emitted by the light source to different propagation directions to form a scanning field of view, wherein the scanning module includes a rotating first optical element and a rotating second optical element, the The first optical element and the second optical element rotate in the same direction or in the opposite direction.

Exemplarily, the angle of view of the scanning field of view is between [10°, 100°].

Exemplarily, the first optical element and the second optical element have different rotation speeds.

Exemplarily, the rotation speed of the first optical element and the second optical element ranges from 3000 rpm to 30,000 rpm.

Exemplarily, the first optical element and the second optical element are sequentially arranged along the propagation direction of the light beam emitted by the light source, wherein the rotation speed of the first optical element is greater than the rotation speed of the second optical element.

Exemplarily, the rotation speed of the second optical element is 50% to 90% of the rotation speed of the first optical element.

Exemplarily, as the scanning time accumulates, the points within the scanning field of view are more and more densely distributed.

Exemplarily, the scanning field of view has a first intermediate region close to a horizontal line to detect a target object with a large vertical length;

The scanning field of view has a second intermediate area close to the vertical line to detect target objects with a large lateral length.

Exemplarily, the first optical element and the second optical element each include a first surface and a second surface that is opposite to the first surface but not parallel, wherein the first surface of the first optical element It is disposed opposite to one of the second surfaces and one of the first surface and the second surface of the second optical element.

Exemplarily, the first surface of the first optical element and the first surface of the second optical element are oppositely arranged, or the second surface of the first optical element and the second surface of the second optical element The surface is set oppositely.

Exemplarily, the first optical element and the second optical element rotate around the same rotation axis, wherein the first surface and the rotation axis are perpendicular, and the second surface is inclined relative to the first surface .

Exemplarily, with the direction in which the thickness of the first optical element and the second optical element decrease fastest is its extending direction, then the relative positions of the first optical element and the second optical element are set In order to extend the second optical element and the first optical element in opposite directions or in the same direction.

Exemplarily, the angle between the two surfaces of the first optical element and the second optical element that are opposite to the exit optical axis of the light source is greater than 80 degrees.

Exemplarily, the two opposite surfaces of the first optical element and the second optical element are respectively perpendicular to the exit optical axis of the light source.

Exemplarily, the first optical element and the second optical element have a transmittance greater than 90% to the wavelength of the light beam emitted by the light source, wherein the first optical element and the second optical element The components are made of glass.

Exemplarily, the refractive index of the light beam emitted by the first optical element and the second optical element to the light source is between 1.1 and 2.2.

Exemplarily, the distance detection device further includes:

The detector is configured to receive at least part of the light beam emitted by the light source and reflected by the object, and obtain the distance between the distance detection device and the object according to the received light beam.

Exemplarily, it also includes a transceiving lens for:

Collimate the light beam emitted by the light source and then exit, and/or,

At least a part of the light beam received by the object is reflected back to the detector.

Exemplarily, the angle of view of the scanning field of view is between [40°, 80°].

Exemplarily, the included angle between the first surface and the second surface of the first optical element and/or the second optical element is between [15°, 21°].

Exemplarily, the first optical element and/or the second optical element include a wedge-shaped prism, and the aperture of the wedge-shaped prism and/or the transceiving lens is between [25 mm, 35 mm].

Exemplarily, the refractive power of the first optical element and/or the second optical element is between [7°, 11°].

Exemplarily, the angle of view of the scanning field of view is between [10°, 20°].

Exemplarily, the angle between the first surface and the second surface of the first optical element and/or the second optical element is between [5°, 9°].

Exemplarily, the first optical element and/or the second optical element include a wedge-shaped prism, and the aperture of the wedge-shaped prism and/or the transceiving lens is between [45 mm, 55 mm].

Exemplarily, the refractive power of the first optical element and/or the second optical element is between [2°, 5°].

Exemplarily, the first optical element and the second optical element are both wedge prisms.

In the distance measuring device of the present invention, the rotating first optical element and the second optical element (such as a rotating double prism) are used to dynamically adjust the direction of the light beam emitted by the light source, which has the following advantages: First, the structure is simple, so it is stable and reliable, and the cost is low , Which is convenient for large-scale popularization and application; and with the accumulation of time, the space coverage becomes larger and larger, so that the spatial information is more and more dense; in addition, the distribution of the laser emission direction on the first optical element and the second optical The rotation speed of the element is very sensitive, so there is a large room for optimization; finally, by adjusting the wedge angle of the prism and the refractive index of the material, the size of the field of view can be easily adjusted.

BRIEF DESCRIPTION

The following drawings of the present invention are used as a part of the present invention to understand the present invention. The drawings show embodiments of the present invention and their descriptions to explain the principles of the present invention.

In the drawings:

FIG. 1 shows a schematic diagram of an embodiment of the distance detection device of the present invention;

2 shows a schematic structural diagram of a scanning module in an embodiment of the present invention;

FIGS. 3A to 3C show schematic diagrams of scanning patterns formed by the first optical element and the second optical element of the scanning module rotating in the same direction at different rotation speeds in one embodiment of the present invention, wherein FIGS. 3A to 3C The four pictures contained in each increase their scanning time from left to right;

FIGS. 4A to 4C show schematic diagrams of scanning patterns formed by the first optical element and the second optical element of the scanning module in different embodiments at different rotation speeds in a reverse rotation, in which FIGS. 4A to 4C The four pictures included in the graph increase in scan time from left to right;

5A shows a schematic diagram of scanning fields of view formed by scanning modules in different ranges in an embodiment of the present invention;

FIG. 5B shows scan point cloud distribution diagrams of the scan module in different scan times in one embodiment of the present invention.

detailed description

In the following description, a large number of specific details are given in order to provide a more thorough understanding of the present invention. However, it is obvious to those skilled in the art that the present invention can be implemented without one or more of these details. In other examples, in order to avoid confusion with the present invention, some technical features known in the art are not described.

It should be understood that the present invention can be implemented in different forms and should not be interpreted as being limited to the embodiments presented herein. Rather, providing these embodiments will make the disclosure thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, the size and relative sizes of layers and regions may be exaggerated for clarity. The same reference numerals denote the same elements throughout.

It should be understood that when an element or layer is referred to as being "on", "adjacent to", "connected to" or "coupled to" another element or layer, it can be directly on the other element or layer On, adjacent to, connected to, or coupled to other elements or layers, or intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on," "directly adjacent to," "directly connected to" or "directly coupled to" another element or layer, there are no intervening elements or layers Floor. It should be understood that although the terms first, second, third, etc. may be used to describe various elements, components, regions, layers and/or portions, these elements, components, regions, layers and/or portions should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Therefore, without departing from the teachings of the present invention, a first element, component, region, layer or section discussed below can be represented as a second element, component, region, layer or section.

Spatial relationship terms such as "below", "below", "below", "below", "above", "above", etc. It can be used here for the convenience of description to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that in addition to the orientations shown in the figures, the spatial relationship terms are intended to include different orientations of the device in use and operation. For example, if the device in the drawings is turned over, then elements or features described as "below" or "below" or "below" the elements will be oriented "above" the other elements or features. Thus, the exemplary terms "below" and "below" can include both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or other orientation) and the spatial descriptors used herein interpreted accordingly.

The terminology used herein is for describing specific embodiments only and is not intended as a limitation of the present invention. As used herein, the singular forms "a", "an", and "said/the" are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms "composition" and/or "comprising", when used in this specification, determine the existence of the described features, integers, steps, operations, elements and/or components, but do not exclude one or more other The presence or addition of features, integers, steps, operations, elements, components, and/or groups. As used herein, the term "and/or" includes any and all combinations of the listed items.

In order to thoroughly understand the present invention, a detailed structure will be proposed in the following description in order to explain the technical solution proposed by the present invention. The preferred embodiments of the present invention are described in detail below. However, in addition to these detailed descriptions, the present invention may have other embodiments.

The present invention provides a distance detection device, including:

The light source is used to emit a light beam;

The scanning module is configured to sequentially change the light beams emitted by the light source to different propagation directions to form a scanning field of view, wherein the scanning module includes a rotating first optical element and a rotating second optical element, The first optical element and the second optical element rotate in the same direction or in the opposite direction.

Hereinafter, the distance detection device of the present invention will be described with reference to FIGS. 1, 2, 3A to 3C, 4A to 4C, and 5A to 5B. On the premise of no conflict, the various embodiments and examples in the present invention can be combined with each other.

FIG. 1 is a schematic diagram of an embodiment of the distance detection device 100. The distance detection device 100 can be used to measure the distance and orientation of the detection object 101 to the distance detection device 100. In one embodiment, the distance detection device 100 may include a radar, such as a laser radar. The distance detection device 100 can detect the distance between the detection object 101 and the distance detection device 100 by measuring the time of light propagation between the distance detection device 100 and the detection object 101, that is, Time-of-Flight (TOF).

The distance detection device 100 includes an optical transceiving device 110 that includes a light source 103, a transceiving lens 104, a detector 105, and an optical path changing element 106. The optical transceiver 110 is used to emit a light beam and receive the returned light, and convert the returned light into an electrical signal. The light source 103 is used to emit a light beam. In one embodiment, the light source 103 may emit a laser beam. The laser beam emitted by the light source 103 is a narrow-bandwidth beam with a wavelength outside the visible light range. The transceiver lens 104 is used to collimate the light beam emitted by the light source 103, and collimate the light beam emitted by the light source 103 into a collimated light beam 119, for example, parallel light.

In one example, the light source 103 may be a laser diode. For the wavelength of the light emitted by the light source 103, in one example, light with a wavelength between 895 nanometers and 915 nanometers can be selected, for example, light with a wavelength of 905 nanometers. In another example, light with a wavelength between 1540 nanometers and 1560 nanometers can be selected, for example light with a wavelength of 1550 nanometers. In other examples, other suitable wavelengths of light can also be selected according to application scenarios and various needs.

The distance detection device 100 further includes a scanning module 102 for sequentially changing the light beams emitted by the light source to different propagation directions to form a scanning field of view. The scanning module 102 is placed on the side of the transceiving lens 104 opposite to the light source 103. The collimated light beam 119 may be projected to the scanning module 102. The scanning module 102 is used to change the transmission direction of the collimated light beam 119 passing through the transceiver lens 104 and project it to the external environment, and project the return light to the transceiver lens 104. The scanning module 102 projects the light beam into the space around the distance detection device 100. In one embodiment, the scanning module 102 may include one or more optical elements, for example, lenses, mirrors, prisms, gratings, optical phased arrays (Optical Phased Array), or any combination of the above optical elements. In one embodiment, multiple optical elements of the scanning module 102 can rotate about a common axis 109 to project light into different directions. In another embodiment, multiple optical elements of the scanning module 102 can rotate about different axes. In yet another embodiment, at least one optical element of the scanning module 102, such as a galvanometer, can vibrate to change the direction of light propagation. In one embodiment, multiple optical elements of the scanning module 102 can rotate at different rotation speeds. In another embodiment, the multiple optical elements of the scanning module 102 can rotate at substantially the same rotational speed.

In one embodiment, the scanning module 102 includes a first optical element 114 and a drive 116 connected to the first optical element 114. The drive 116 is used to drive the first optical element 114 to rotate about a rotation axis 109 to change the first optical element 114 The direction of the collimated light beam 119. The first optical element 114 projects the collimated light beam 119 in different directions. In one embodiment, the first optical element 114 includes a wedge-angle prism that aligns the straight beam 119 for refraction. In one embodiment, the first optical element 114 is coated with an antireflection coating, which can increase the intensity of the transmitted light beam.

In the embodiment shown in FIG. 1, the scanning module 102 includes a second optical element 115, the second optical element 115 rotates about a rotation axis 109, and the first optical element 114 and the second optical element 115 rotate in the same direction or in the opposite direction Spin.

In one embodiment, the first optical element 114 and the second optical element 115 each include a first surface and a second surface that is opposite to the first surface and not parallel, and the light beam passes through the pair of surfaces, along In accordance with the extending direction of the first surface or the second surface, the thicknesses of the first optical element 114 and the second optical element 115 gradually increase from one end to the opposite end.

In one example, one of the first surface and the second surface of the first optical element is disposed opposite to one of the first surface and the second surface of the second optical element. In one example, the first optical element 114 and the second optical element 115 rotate about the same rotation axis, wherein the first surface and the rotation axis 109 are perpendicular, and the second surface is opposite to the first One surface is set obliquely. In one example, the rotation axes of the first optical element and the second optical element are parallel to or in a straight line with the optical axis of the light beam emitted by the light source.

In one example, as shown in the left diagram of FIG. 2, the second surface of the first optical element 114 and the second surface of the second optical element 115 are oppositely arranged such that the first surface faces outward, for example , The collimated light beam 119 first passes through the first surface of the first optical element 114. In another example, as shown in the right diagram shown in FIG. 2, the first surface of the first optical element 114 and the first surface of the second optical element 115 are oppositely arranged such that the second surface faces outward. In both cases shown in FIG. 2, the first optical element 114 and the second optical element 115 are arranged in reverse, that is, the thickness of the first optical element 114 and the second optical element 115 decreases most. The fast direction is its extending direction, then the relative positions of the first optical element 114 and the second optical element 115 are set such that the extending directions of the second optical element 115 and the first optical element 114 are opposite .

In another example, as shown in FIG. 1, the relative position of the first optical element 114 and the second optical element 115 is set such that the extension of the second optical element 115 and the first optical element 114 The same direction.

The rotation speed of the second optical element 115 is different from the rotation speed of the first optical element 114. The second optical element 115 changes the direction of the light beam projected by the first optical element 114. In one example, the rotation speed of the first optical element 114 and the second optical element 115 ranges from 3000 rpm to 30,000 rpm, where rpm refers to revolutions per minute. Optionally, the first optical element 114 and the second optical element 115 are sequentially arranged along the propagation direction of the light beam emitted by the light source, wherein the rotation speed of the first optical element 114 is greater than that of the second optical element The rotation speed of 115, for example, the rotation speed of the second optical element is 50% to 90% of the rotation speed of the first optical element, for example, 60%, 70%.

The rotation speeds of the first optical element 114 and the second optical element 115 can be reasonably set according to the actual needs of the scanning field of view. In one example, the first optical element 114 and the second optical element 115 rotate in the same direction , The scanning field of view consists of a plurality of approximately circular (or approximately heart-shaped) scanning trajectories intersecting the center of the scanning field of view, and the overall scanning field of view is approximately circular or elliptical, as shown in FIGS. 3A to 3C, The four scanning fields of view shown from left to right in FIG. 3A are the patterns of the scanning field of view when the scanning integration time is 100 ms, 200 ms, 400 ms, and 1000 ms. As shown in FIG. 3A, the rotation speed of the first optical element 114 When it is between [12000rpm, 12100rpm], and the rotation speed of the second optical element 115 is between [7250rpm, 7350rpm], the pattern of the scanned field of view is formed; as shown in FIG. 3B, in the first optical element 114 When the rotation speed is between [7900rpm, 8000rpm], and the rotation speed of the second optical element 115 is between [4800rpm, 4900rpm], the pattern of the scanned field of view is formed; as shown in FIG. 3C, in the first optical element When the rotation speed of 114 is between [9150rpm, 9250rpm] and the rotation speed of the second optical element 115 is between [5600rpm, 5700rpm], the pattern of the scanned field of view is formed; and, the right figure can also be seen, as the scan As time accumulates, the points in the field of view are getting denser and denser.

In another example, the first optical element 114 and the second optical element 115 rotate in opposite directions, for example, one rotates counterclockwise and the other rotates clockwise. The scanning field of view consists of multiple ellipses that intersect the center of the scanning field of view The scanning trajectory of the whole constitutes a circular or elliptical scanning field of view. One end of the elliptical scanning trajectory is located at the center of the scanning field of view and the other end extends outward in the radial direction, as shown in FIGS. 4A to 4C, and FIG. 4A The four scanning fields of view shown from left to right in the middle are the patterns of the scanning fields of view when the scanning time is 100ms, 200ms, 400ms, and 1000ms, as shown in FIG. 4A, at the rotation speed of the first optical element 114 [7750rpm , 7900rpm], when the rotation speed of the second optical element 115 is located between [5950rpm, 6050rpm], the pattern of the scanned field of view is formed; as shown in FIG. 4B, the rotation speed of the first optical element 114 is located at [ 7800rpm, 7950rpm], when the rotation speed of the second optical element 115 is located at [4750rpm, 4900rpm], the pattern of the scanned field of view is formed; as shown in FIG. 4C, the rotation speed of the first optical element 114 is located at [ 7250rpm, 7350rpm], when the rotation speed of the second optical element 115 is between [4600rpm, 4750rpm], the pattern of the scanned field of view is formed; and, the right figure can also be seen, as the scanning time accumulates, the The points in the field are getting denser and denser.

In other examples, the rotation speed of the first optical element 114 is between [7000rpm, 8000rpm,], and the rotation speed of the second optical element 115 is between [4850rpm, 4950rpm]; the rotation speed of the first optical element 114 is [9400rpm, 9500rpm], the rotation speed of the second optical element 115 is located between [6050rpm, 610rpm,]; the rotation speed of the first optical element 114 is located between [9300rpm, 9400rpm,], the rotation speed of the second optical element 115 The rotation speed is between [6000rpm, 6100rpm]; the rotation speed of the first optical element 114 is between [9300rpm, 9400rpm], the rotation speed of the second optical element 115 is between [5700rpm, 5800rpm]; the first optical element The rotation speed of 114 is between [9200rpm, 9300rpm], the rotation speed of the second optical element 115 is between [5900rpm, 6000rpm]; the rotation speed of the first optical element 114 is between [9100rpm, 9200rpm], the second optical element The rotation speed of 115 is between [5900rpm, 6000rpm]; the rotation speed of the first optical element 114 is between [9400rpm, 9500rpm], the rotation speed of the second optical element 115 is between [6050rpm, 6150rpm]; the first The rotation speed of the optical element 114 is between [9400rpm, 9500rpm], the rotation speed of the second optical element 115 is between [6050rpm, 6150rpm]; the rotation speed of the first optical element 114 is between [9400rpm, 9500rpm], the second The rotation speed of the optical element 115 is between [6050 rpm, 6150 rpm]; the rotation speed of the first optical element 114 is between [9100 rpm, 9200 rpm], and the rotation speed of the second optical element 115 is between [5850 rpm, 5950 rpm]. The combination of the above rotation speeds can also achieve a scanning field of view that meets the requirements. For example, when the first optical element 114 and the second optical element 115 rotate in reverse, a scanning field of view similar to that in FIGS. 4A to 4C is formed. The first optical element 114 It rotates in the same direction as the second optical element 115 to form a scanning field of view similar to FIGS. 3A to 3C.

In one embodiment, the second optical element 115 is connected to another driver 117, and the driver 117 drives the second optical element 115 to rotate. The first optical element 114 and the second optical element 115 can be driven by different drivers, so that the rotation speeds of the first optical element 114 and the second optical element 115 are different, so that the collimated light beam 119 is projected into different directions in the external space and can be scanned Larger spatial range. In one embodiment, the controller 118 controls the

drivers

116 and 117 to drive the first optical element 114 and the second optical element 115, respectively. The rotation speeds of the first optical element 114 and the second optical element 115 may be determined according to the area and pattern expected to be scanned in practical applications. The

drives

116 and 117 may include motors or other driving devices.

In one embodiment, the second optical element 115 includes a wedge angle prism. In one embodiment, the second optical element 115 is coated with an antireflection coating, which can increase the intensity of the transmitted light beam.

The material of the first optical element and the second optical element may be any suitable light-transmitting material with high transmittance. In one embodiment, the first optical element and the second optical element are The wavelength of the light beam emitted from the light source has a transmittance greater than 90%, wherein the first optical element and the second optical element are glass materials, for example, HK9L glass materials.

The refractive indexes of the first optical element 114 and the second optical element 115 are affected by the wavelength of the light beam emitted by the light source. The longer the wavelength, the smaller the refractive index. Optionally, the first optical element 114 and the The refractive index of the light beam emitted by the light source of the second optical element 115 is between 1.1 and 2.2, for example, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8 and so on. For example, if the wavelength of the light beam emitted by the light source is about 905 nm, the refractive index of the first optical element 114 and the second optical element 115 of the glass material to the light beam of 905 nm wavelength is 1.50895.

The angle range between the first surface and the second surface of the first optical element is 5-25°; and/or, the angle range between the first surface and the second surface of the second optical element When the first optical element 114 and the second optical element 115 are both prisms, the included angle also becomes a wedge angle. In this embodiment, the first optical element and the second optical element The wedge angle can be 18°, or another suitable angle.

In one example, the angle between the two surfaces of the first optical element and the second optical element opposite to the exit optical axis of the light source is greater than 80 degrees. In another example, the two opposite surfaces of the first optical element and the second optical element are respectively perpendicular to the exit optical axis of the light source. In yet another example, the included angle between the first surface and the second surface of the first optical element and/or the second optical element is located at [15°, 21°], thereby obtaining a scanning field of view The field of view can be located at [40°, 80°]. In other examples, the included angle between the first surface and the second surface of the first optical element and/or the second optical element is located at [5°, 9°], whereby the scan can be obtained The angle of view of the field of view is [10°, 20°].

Specifically, the wedge angle and material refractive index of the first optical element (such as a prism) and the second optical element (such as a prism) can be adjusted, thereby conveniently adjusting the size of the field of view.

The scanning field of view is formed by the above scanning module, for example, the field of view of the scanning field of view is between [10°, 100°]. In an example, as shown in FIG. 5A, scanning fields of view in different ranges are shown, where (a) in FIG. 5A is the scanning field of view when the field angle is 2°×2°, and (b) is the field of view The scanning field of view when the angle is 20°×20°, and (c) shows the scanning field of view when the field angle is 100°×100°. In one example, the field of view of the scanning field of view is located at [40°, 80°], and in other examples, the field of view of the scanning field of view is located at [10°, 20°].

In one example, the refractive power of the first optical element and/or the second optical element is located at [7°, 11°], and the angle of view of the scanning field of view is located at [40°, 80°]; In another example, the refractive power of the first optical element and/or the second optical element is located at [2°, 5°], and the angle of view of the scanning field of view is located at [10°, 20°] . The refractive power of an optical element refers to the deflection angle of the emitted light compared to the incident light when the incident light is perpendicular to the light incident surface. The difference in refractive power is less than 10 degrees, which can mean that the deflection direction of the incident light is the same when the incident light is perpendicular to the light incident surface, but the difference of the deflection angle is less than 10 degrees; or the deflection direction is different, but the deviation The angle of the folding direction is less than 10 degrees.

Due to the rotation of the specific first optical element and the second optical element (for example, a double prism), the formed scanning field of view (also referred to as a scanning pattern) has the following characteristics:

First, within a specific scanning time, the point cloud distribution in the field of view is relatively uniform;

Furthermore, as the scan time accumulates, the points in the field of view are getting denser and denser. As shown in FIG. 5B, comparing (a) in FIG. 5B with (b) in FIG. 5B, the scanning time corresponding to (b) in FIG. 5B is five times that in (a) in 5B, and the point cloud is also more Fine.

Furthermore, as shown in (a) of FIG. 5B, the scanning field of view has a first intermediate region 1 close to the horizontal line to detect a target object with a large vertical length. For example, in the When the distance detection device of the invention is applied to scenes such as automatic driving, it is convenient to detect target objects with relatively large lateral lengths such as electric wires and roadblocks. As shown in (a) of FIG. 5B, the scanning field of view has a second intermediate region 2 close to a vertical line to detect a target object with a large lateral length. For example, in the distance detection device of the present invention When applied to scenarios such as automatic driving, it is convenient to detect target objects such as pedestrians with relatively large lateral lengths.

The above-mentioned scanning module 102 can be applied not only to lidar, but also to laser guidance, space optical communication, and precision tracking systems.

The rotation of the scanning module 102 can project light into different directions, such as

directions

111 and 113, thus scanning the space around the distance detecting device 100. When the light 111 projected by the scanning module 102 hits the detection object 101, a part of the light is reflected by the detection object 101 to the distance detection device 100 in a direction opposite to the projected light 111. The scanning module 102 receives the return light 112 reflected by the detection object 101 and projects the return light 112 to the transceiver lens 104.

The transceiver lens 104 condenses at least a part of the return light 112 reflected by the probe 101. In one embodiment, the transceiving lens 104 is coated with an AR coating, which can increase the intensity of the transmitted beam. The detector 105 and the light source 103 are placed on the same side of the transceiving lens 104. The detector 105 is used to convert at least part of the returned light passing through the transceiving lens 104 into an electrical signal. In some embodiments, the detector 105 may include an avalanche photodiode. The avalanche photodiode is a high-sensitivity semiconductor device capable of converting an optical signal into an electrical signal using the photocurrent effect.

In one example, the first optical element and/or the second optical element include a wedge-shaped prism, and the aperture of the wedge-shaped prism and/or the transceiver lens is between [25 mm, 35 mm]. The angle of view of the scanning field of view is between [30°, 90°], and further may be between [40°, 80°]. The detection distance is between [100m, 360m], and even further between [200m, 300m].

In another example, the first optical element and/or the second optical element include a wedge-shaped prism, and the aperture of the wedge-shaped prism and/or the transceiver lens is between [45 mm, 60 mm]. The field of view of the scanning field of view is between [10°, 20°], the detection distance is between [400m, 650m], and further may be between [500m, 600m]. The collimator lens (that is, the transceiver lens) has a large aperture, so it can receive more echo energy, and the radar reception signal is enhanced. As the focal length of the lens increases, the spatial angle of the noise light that can be received by the avalanche photodiode (APD) will decrease, and the noise will decrease. Therefore, the ranging distance can become longer.

In some embodiments, the distance detection device 100 includes a measurement circuit, such as a TOF unit 107, which can be used to measure TOF to measure the distance of the detection object 101. For example, the TOF unit 107 can calculate the distance by the formula t=2D/c, where D represents the distance between the distance detection device and the detection object, c represents the speed of light, and t represents the light projected from the distance detection device to the detection object and from the detection The total time it takes for the object to return to the distance detection device. The distance detection device 100 may determine the time t according to the time difference between the light beam emitted by the light source 103 and the return light received by the detector 105, and then the distance D may be determined. The distance detection device 100 can also detect the orientation of the detection object 101 in the distance detection device 100. The distance and orientation detected by the distance detection device 100 can be used for remote sensing, obstacle avoidance, mapping, modeling, navigation, and the like.

In some embodiments, the light source 103 may include a laser diode through which laser light in the nanosecond level is emitted. For example, the laser pulse emitted by the light source 103 lasts for 10 ns, and the pulse duration of the return light detected by the detector 105 is substantially equal to the duration of the emitted laser pulse. Further, the laser pulse receiving time may be determined, for example, the laser pulse receiving time may be determined by detecting the rising edge time of the electrical signal pulse. In some embodiments, the electrical signal may be amplified in multiple stages. In this way, the distance detection device 100 can calculate the TOF using the pulse reception time information and the pulse emission time information, thereby determining the distance from the detection object 101 to the distance detection device 100.

In the illustrated embodiment, the optical path changing element 106, the light source 103, and the detector 105 are placed on the same side of the transceiving lens 104, and the optical path changing element 106 is used to change the optical path of the light beam emitted by the light source 103 or the return light passing through the transceiving lens 104 Light path. One of the detector 105 and the light source 103 is placed on the focal plane of the transceiver lens 104, and the other is placed on one side of the optical axis of the transceiver lens 104. The “focal plane” here refers to a plane that passes through the focal point of the transceiver lens 104 and is perpendicular to the optical axis of the transceiver lens 104. In one embodiment, the distance detection device 100 may include an optical path changing element 106. In another embodiment, the distance detection device 100 may include a plurality of optical path changing elements 106 to change the optical path of the emitted light beam or the optical path of the returning light multiple times.

The transceiver lens 104 can collimate the light beam emitted by the light source 103 and can converge back light. The light path changing element 106 can change the light path of the light beam emitted by the light source 103 or the return light, so that the light transmission and return light reception can share the transceiver lens 104, so that the distance The structure of the detection device 100 is more compact and more compact. Moreover, make full use of lenses to reduce costs.

In some embodiments, the distance detection device 100 includes a window (not shown) on the side of the scanning module 102 opposite to the transceiver lens 104, the light projected by the scanning module 102 passes through the window and projects to the outside space, and the return light can pass through Through the window to the scanning module 102. The light source 103, the detector 105, the optical path changing element 106, the transceiving lens 104, and the scanning module 102 may be packaged in the packaging device, and the window is formed in the packaging device. In one embodiment, the window may include a glass window. In one embodiment, the window is coated with a long wave pass film. In one embodiment, the long-wave pass film has a low transmittance of visible light of about 400 nm-700 nm, and a high transmittance of light in the wavelength band of the emitted light beam.

In one embodiment, at least one of the inner surface of the window, the surface of the scanning module 102, the surface of the transceiving lens 104, the surface of the optical path changing element 106, and the surface of the lens of the detector 105 is coated with a positive water film. The positive water film is a hydrophilic film. When the distance detection device 100 generates heat, the volatile oil can be spread out on the surface of the positive water film to prevent the oil from forming oil droplets on the surface of the optical element, thereby avoiding the influence of the oil droplets on light propagation. In some embodiments, the surface of the other optical elements of the distance detection device 100 may be coated with a positive water film. In the embodiment shown in FIG. 1, the relatively non-parallel surfaces of the first optical element 114 and the relatively non-parallel surfaces of the second optical element 115 of the scanning module 102 may be plated with a positive water film.

In the distance measuring device of the present invention, the rotating first optical element and the second optical element (such as a rotating double prism) are used to dynamically adjust the exit direction of the light source, which has the following advantages: first, the structure is simple, so it is stable and reliable, and the cost is low, It is convenient for large-scale popularization and application; and as time accumulates, the space coverage becomes larger and larger, so that the spatial information becomes more and more dense; in addition, the distribution of the laser emission direction is sensitive to the speed change of the double prism, thus There is more room for optimization; finally, by adjusting the wedge angle of the prism and the refractive index of the material, the size of the field of view can be easily adjusted.

The present invention has been described through the above-mentioned embodiments, but it should be understood that the above-mentioned embodiments are only for purposes of illustration and description, and are not intended to limit the present invention to the scope of the described embodiments. In addition, those skilled in the art can understand that the present invention is not limited to the above-mentioned embodiments, and more variations and modifications can be made according to the teachings of the present invention, and these variations and modifications fall within the scope of protection claimed by the present invention. Within range. The protection scope of the present invention is defined by the appended claims and their equivalent scope.

Claims

A distance detection device, characterized in that it includes:

Light source, used to emit light beam;

A scanning module, configured to sequentially change the light beams emitted by the light source to different propagation directions to form a scanning field of view, wherein the scanning module includes a rotating first optical element and a rotating second optical element, the The first optical element and the second optical element rotate in the same direction or in the opposite direction.
The distance detection device according to claim 1, wherein the angle of view of the scanning field of view is between [10°, 100°].
The distance detecting device according to claim 1, wherein the first optical element and the second optical element have different rotation speeds.
The distance detection device according to claim 1, wherein the rotation speed of the first optical element and the second optical element ranges from 3000rpm to 30000rpm.
The distance detection device according to claim 1, wherein the first optical element and the second optical element are sequentially arranged along the propagation direction of the light beam emitted by the light source, wherein the The rotation speed is greater than the rotation speed of the second optical element.
The distance detecting device according to claim 1, wherein the rotation speed of the second optical element is 50% to 90% of the rotation speed of the first optical element.
The distance detecting device according to claim 1, characterized in that, as the scanning time accumulates, the points in the scanning field of view are distributed more and more densely.
The distance detecting device according to claim 1, wherein the scanning field of view has a first intermediate region close to a horizontal line to detect a target object with a large vertical length;

The scanning field of view has a second intermediate area close to the vertical line to detect target objects with a large lateral length.
The distance detection device according to claim 1, wherein each of the first optical element and the second optical element includes a first surface and a second surface that is opposite to the first surface and not parallel to each other, wherein , One of the first surface and the second surface of the first optical element is disposed opposite to one of the first surface and the second surface of the second optical element.
The distance detection device according to claim 9, wherein the first surface of the first optical element and the first surface of the second optical element are oppositely arranged, or the second surface of the first optical element The surface is disposed opposite to the second surface of the second optical element.
The distance detecting device according to claim 9, wherein the first optical element and the second optical element rotate around the same rotation axis, wherein the first surface and the rotation axis are perpendicular, the The second surface is inclined relative to the first surface.
The distance detection device according to claim 10, characterized in that the direction in which the thickness of the first optical element and the second optical element decreases most rapidly is its extending direction, then the first optical element The relative position to the second optical element is set such that the extension directions of the second optical element and the first optical element are opposite or the same.
The distance detection device according to claim 9, characterized in that the angle between the two surfaces of the first optical element and the second optical element opposite to the exit optical axis of the light source is greater than 80 degrees .
The distance detecting device according to claim 9, wherein two surfaces of the first optical element and the second optical element opposite to each other are respectively perpendicular to the exit optical axis of the light source.
The distance detection device according to claim 1, wherein the first optical element and the second optical element have a transmittance greater than 90% to the wavelength of the light beam emitted by the light source, wherein The first optical element and the second optical element are glass materials.
The distance detection device according to claim 1, wherein the refractive index of the light beam emitted by the first optical element and the second optical element to the light source is between 1.1 and 2.2.
The distance detection device according to any one of claims 1 to 15, wherein the distance detection device further comprises:

The detector is configured to receive at least part of the light beam emitted by the light source and reflected by the object, and obtain the distance between the distance detection device and the object according to the received light beam.
The distance detection device according to claim 17, further comprising a transceiver lens for:

Collimate the light beam emitted by the light source and then exit, and/or,

At least a part of the light beam received by the object is reflected back to the detector.
The distance detecting device according to claim 1, wherein the field angle of the scanning field of view is between [30°, 90°].
The distance detection device according to claim 1 or 19, wherein the angle between the first surface and the second surface of the first optical element and/or the second optical element is located at [15°, 21°].
The distance detecting device according to claim 1 or 19, wherein the first optical element and/or the second optical element comprise a wedge-shaped prism, and the aperture of the wedge-shaped prism and/or the transceiver lens is located at [25mm, 35mm].
The distance detecting device according to claim 1 or 19, wherein the refractive power of the first optical element and/or the second optical element is between [7°, 11°].
The distance detecting device according to claim 1 or 18, wherein the distance measuring distance of the distance detecting device is between [200m, 300m].
The distance detecting device according to claim 1, wherein the angle of view of the scanning field of view is between [10°, 20°].
The distance detecting device according to claim 1 or 24, wherein the angle between the first surface and the second surface of the first optical element and/or the second optical element is located at [5°, 9°].
The distance detecting device according to claim 1 or 24, wherein the first optical element and/or the second optical element comprise a wedge-shaped prism, and the aperture of the wedge-shaped prism and/or the transceiver lens is located at [45mm, 60mm].
The distance detecting device according to claim 1 or 24, wherein the refractive power of the first optical element and/or the second optical element is between [2°, 5°].
The distance detecting device according to claim 1 or 24, characterized in that the distance measuring distance of the distance detecting device is between [500m, 600m].
The distance detecting device according to any one of claims 1 to 18, wherein the first optical element and the second optical element are both wedge-shaped prisms.