KR102363318B1 - Miniaturized Lidar Optical System - Google Patents

Abstract

The non-rotational 360-degree lidar optical system and the non-rotational 360-degree scanning method of the lidar optical system according to the embodiment rotate the aspherical reflector, which is a scanning mechanism composed of a four-sided cube having a reflective surface, rather than rotating the laser device itself. It scans around 360 degrees. Accordingly, it is possible to scan all around 360 degrees by the light reflected by the aspherical reflector and the beam splitter even without powering the lidar optical system.

Description

Miniaturized Lidar Optical System

It relates to a non-rotational 360-degree lidar optical system and a non-rotational 360-degree scanning method of the lidar optical system. Specifically, a non-rotational 360-degree lidar that rotates a reflector without rotating the optical system laser device itself to scan the surroundings by 360 degrees It relates to optical systems.

Unless otherwise indicated herein, the material described in this section is not prior art to the claims of this application, and inclusion in this section is not an admission that it is prior art.

Lidar is a device that precisely draws out the surroundings by emitting a laser pulse, receiving the light reflected from the surrounding target object, and measuring the distance to the object. LiDAR is used for not only the distance to the target, but also the speed and direction of movement, temperature, and analysis and concentration of surrounding atmospheric substances. It can detect non-metallic rocks, clouds, raindrops, aerosols, etc. using ultraviolet, visible light, and near-infrared rays, so it can be used for weather observation, to accurately draw terrain, to guide the landing of an aircraft, or to recognize the surroundings of an autonomous vehicle. It is used as a device and is also used to find out the chemical composition of a gas mixed in the air by using the phenomenon that the wavelength of light that scatters well for each molecule is different.

Recently, lidar has emerged as a core technology of a sensor that acquires information necessary to implement a three-dimensional image. If the topography is surveyed by analyzing the spatial location of the reflection point by measuring the return time by firing laser pulses on the ground while flying with the lidar mounted on the aircraft, the reflection and return time varies depending on the structure, so the optical image is obtained from this. It is possible to obtain a 3D model that is difficult to obtain with In addition, the ground lidar can obtain precise data by combining the position coordinates obtained by GPS with this.

In order to obtain a 3D model, it is common for a lidar system to include a scanner and a receiver. The scanner is a part that allows you to quickly scan the surroundings to obtain information, and various types of mirrors are used for scanning. The receiver is a part that detects the returning light, and the sensitivity of the receiver to the light is a major factor influencing the performance of the lidar. Essentially, the receiver detects photons and amplifies them. The positioning system is a part that confirms the position coordinates and direction where the receiver is placed in order to implement a 3D image.

The conventional lidar system requires dynamic movement such as rotation of a scanner that emits lidar for 360-degree peripheral scanning. However, when the laser radiation device itself is rotated, since a large rotational power is required, there is a problem in that the integration efficiency of the lidar system is lowered by the configuration that supplies power such as a motor.

1. Korean Patent Publication No. 10-2019-0083145 (2019.07.11)

The non-rotational 360-degree lidar optical system and the non-rotational 360-degree scanning method of the lidar optical system according to the embodiment rotate the aspherical reflector, which is a scanning mechanism composed of a four-sided cube having a reflective surface, rather than rotating the laser device itself. It scans around 360 degrees. Accordingly, it is possible to scan all around 360 degrees by the light reflected by the aspherical reflector and the beam splitter even without powering the lidar optical system.

A non-rotating 360-degree lidar optical system according to an embodiment includes: a Vertical-Cavity Surface-Emitting Laser (VCSEL) emitting a laser for scanning a three-dimensional environment; an aspherical reflector connected to the rotating device and reflecting the laser emitted from the VCSEL; a beam splitter for collecting reflected light reflected from an aspherical reflector; a light receiving unit for receiving the reflected light reflected from the beam splitter; and the aspherical reflector, the beam splitter, and the VCSEL are aligned with respect to the optical axis, which is the central axis of the aspherical reflector.

A non-rotational 360-degree scanning method of a lidar optical system including a VCSEL, an aspherical reflector, a beam splitter, and a light receiver according to another embodiment (A) For three-dimensional environment scanning in a VCSEL (Vertical-Cavity Surface-Emitting Laser) radiating a laser; (B) reflecting the laser emitted from the VCSEL in the aspherical reflector connected to the rotating device; (C) collecting the reflected light reflected from the aspherical reflector in the beam splitter (Beam Splitter); (D) receiving the reflected light reflected from the beam splitter in the light receiving unit; including, the aspherical reflector, the beam splitter, and the VCSEL are aligned with respect to an optical axis that is a central axis of the aspherical reflector.

The non-rotational 360-degree lidar optical system and the non-rotational 360-degree scanning method of the lidar optical system as described above do not require rotation of the laser device itself, so peripheral scanning is possible without a technical configuration that supplies power to the system, and the scanning speed and improve the circuit integration efficiency of the lidar optical system. In addition, since the aspherical reflector, which is the scanning mechanism according to the embodiment, can be rotated at a high speed with less force, by increasing the number of rotations and scanning of the reflector, it is possible to more precisely grasp the change in movement of the surrounding object in a short time.

In addition, since the lidar optical system can be miniaturized, it can be applied to a small robot or small equipment.

It should be understood that the effects of the present invention are not limited to the above-described effects, and include all effects that can be inferred from the configuration of the invention described in the detailed description or claims of the present invention.

1 is a view showing a non-rotating 360 degree lidar optical system according to an embodiment;
2 is a view for explaining in more detail the incident light, reflected light, and the system configuration of the non-rotation 360 degree lidar optical system according to the embodiment;
3 is a view showing components of a non-rotating 360 degree lidar optical system according to an embodiment;
4 is a diagram showing an additional configuration of a VCSEL according to an embodiment;
5 is a diagram illustrating a data processing flow of a 360-degree non-rotational scanning method of a lidar optical system according to an embodiment;
6 is a view showing an example of use of a non-rotating 360 degree lidar optical system according to an embodiment

Advantages and features of the present invention, and a method for achieving them will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms, and only these embodiments allow the disclosure of the present invention to be complete, and common knowledge in the technical field to which the present invention belongs It is provided to fully inform the possessor of the scope of the invention, and the present invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout.

In describing the embodiments of the present invention, if it is determined that a detailed description of a well-known function or configuration may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. In addition, the terms to be described later are terms defined in consideration of functions in an embodiment of the present invention, which may vary according to intentions or customs of users and operators. Therefore, the definition should be made based on the content throughout this specification.

1 is a view showing a non-rotating 360 degree lidar optical system according to an embodiment.

Referring to FIG. 1 , a non-rotational 360-degree lidar optical system according to an embodiment includes a Vertical-Cavity Surface-Emitting Laser (VCSEL) 100 , an aspherical reflector 600 , a beam splitter 300 , and a light receiver 500 . and alignment detection sensors 61 , 62 , 63 and 64 may be configured.

The VCSEL (Vertical-Cavity Surface-Emitting Laser) 100 emits a laser (irradiation light) for 3D environment scanning. In an embodiment, the VCSEL 100 is a kind of semiconductor laser diode that emits a laser in a direction perpendicular to the upper surface.

The aspherical reflector 600 is connected to a rotating device 610 that rotates the reflective surface 60a-1 of the aspherical reflector and reflects the laser emitted from the VCSEL 100 .

Alignment detection sensors 61, 62, 63, and 64 for detecting alignment of the aspherical reflector and the VCSEL may be installed on the left and right reflective surfaces of the aspherical reflector 600 in the embodiment. For example, the alignment detection sensors 61, 62, 63, and 64 are installed on the left and right sides of the reflective surface 61a-1 of the aspherical reflector 600, respectively, in relation to the on-off relationship of the sensor or the position of the reflective surface on which the laser is incident. The alignment relationship between the VCSEL 100 and the aspherical reflector 600 may be calculated by determining the amount of laser incident to each sensor.

Specifically, when the alignment of the VCSEL 100 and the aspherical reflector 600 is perfect, in the embodiment, the center between the left alignment detection sensors 61 and 63 and the center between the right alignment detection sensors 62 and 64 VCSEL ( The laser output from 100) is incident, and both the left alignment detection sensors 61 and 63 and the right alignment detection sensors 62 and 64 show an off state.

If the alignment of the VCSEL 100 and the aspherical reflector 600 is disturbed and the aspherical reflector is deflected to the left, the left alignment sensor 61 located on the left of the aspherical reflector left alignment detecting sensors 61 and 63 is turned on , the left alignment detection sensor (63) located on the right of the left alignment detection sensors (61, 63) is turned off. In the embodiment, when the on-off state of the sensor installed on the same side of the aspherical reflector is different, or the laser incident amount detected by the sensor is different from the incident amount in the alignment state, it is determined that the alignment relationship between the aspherical reflector 600 and the VCSEL is out of alignment, , it is possible to determine the direction and degree of the misalignment according to the amount of laser light incident on each of the alignment detection sensors 61, 62, 63, and 64.

In addition, when the alignment of the VCSEL 100 and the aspherical reflector 600 is disturbed and the aspherical reflector is deflected to the right, the alignment detecting sensor 62 located on the right side of the aspherical reflector right alignment detecting sensors 62 and 64 is turned on. and the left alignment detection sensor 64 among the right alignment detection sensors 62 and 64 is turned off. In the embodiment, when the on-off state of the sensor installed on the same side of the aspherical reflector is different, or the laser incident amount detected by the sensor is different from the incident amount in the perfect alignment state, it is determined that the alignment relationship between the aspherical reflector 600 and the VCSEL is out of alignment And, according to the amount of laser light incident on each of the alignment detection sensors 61, 62, 63, 64, the direction and degree of misalignment can be identified and notified.
The beam splitter 300 is disposed so that the reflected light reflected from the aspherical reflector 600 is introduced. The beam splitter 300 is a device for entering an incident light beam into an incident surface and a reflective surface, and is used for an optical element, an interferometer, and the like. In the embodiment, the beam splitter 300 includes an incident surface and a reflective surface, and may be configured as a semi-transparent mirror.
The beam splitter 300 reflects the reflected light introduced from the aspherical reflector 600 to proceed to the light receiver 500 .

delete

The light receiver 500 receives the reflected light reflected from the beam splitter.

2 is a view for explaining in more detail incident light, reflected light, and system configuration of the non-rotational 360 degree lidar optical system according to the embodiment.

As shown in FIG. 2, the aspherical reflector 600, the beam splitter 300, and the VCSEL 100 of the non-rotational 360 degree lidar optical system according to the embodiment are aligned with the optical axis c, which is the central axis of the aspherical reflector. It forms a non-rotating 360 degree lidar optical system.

Figure 2 (a) is a view showing that the non-rotation 360 degree lidar optical system according to the embodiment is installed, (b) is a non-rotation 360 degree lidar optical system shown in (a) inside is an enlarged view of

Referring to (a) of Figure 2, the actually installed non-rotation 360 degree lidar optical system may be composed of a connecting device 610, a reflector portion (W1), and a receiving portion (W2). The reflector portion W1 emits the irradiated light by the aspherical reflector rotating in the direction of the arrow to the surrounding object and collects the reflected light reflected from the surrounding object. The receiving part W2 is a part including a beam splitter, a VCSEL, and an optical receiver, and collects the reflected light reflected by the beam splitter in the optical receiver so that a 360-degree surrounding environment can be grasped.

Hereinafter, the path of the light source will be described in more detail with reference to FIG. 2B.

When the laser is irradiated from the VCSEL 100, which is the light source according to the embodiment, to the aspherical reflector 600, the aspherical reflector rotates and scans the surroundings through the irradiated laser, and the reflected light (object light) reflected by the scanned surrounding object is Enter the beamsplitter. The reflective surface of the beam splitter reflects the reflected light reflected by the surrounding object again, and the reflected light reflected by the reflective surface of the beam splitter is collected by the light receiver.
2 , a non-rotating 360 degree lidar optical system according to an embodiment; may further include a collimation lens unit 400 for checking an alignment relationship and a center line of the aspherical reflector, the beam splitter, and the VCSEL.
The collimation lens unit 400 may include a collimation lens that is a focusing lens and a plurality of Avalanche Photo Diode (APD) arrays. In an embodiment, the collimation lens 400 may be aligned at a beam splitter angle between the beam splitter 300 and the light receiver 500 . The collimation lens 400 is an electron lens used to collect the electron-emitted electron beam back to the sample surface. In the embodiment, the collimation lens 400 focuses the electron beam reflected from the beam splitter 300 to the light receiver 500 .
The non-rotating 360-degree lidar optical system according to the embodiment grasps the alignment relationship between the aspherical reflector and the optical axis, and when the aspherical reflector is tilted in one direction, such as tilted by a certain ratio, it is displayed and corrected.
In an embodiment, the light receiving unit 500 may detect an alignment error when the optical axis alignment of the VCSEL, the beam splitter, and the aspherical reflector is misaligned with the central axis of the aspherical reflector or is deviated by more than a certain level. The light receiver 500 may post-correction of the received light according to the direction and level of the detected alignment error.
Also, the light receiving unit 500 may provide an error amount to the manager so that the VCSEL, the beam splitter, and the aspherical reflector are aligned again. In addition, the light receiving unit 500 transmits the error amount to a controller (not shown) that controls each configuration of the non-rotational 360-degree lidar optical system, and the controller moves the VCSEL, the beam splitter, and the aspherical reflector according to the error amount. This allows the optical axis to be aligned.
For example, when the VCSEL 100 is biased to the right, since more light is irradiated to the right than to the left from the aspherical reflector, the light receiving unit 500 senses the deflected dose to determine which components of the non-rotational 360 degree lidar optical system freeze. It is judged whether there is a misalignment, and the misaligned components are rearranged according to the confirmed error amount.

delete

delete

delete

In addition, when the beam splitter 300 is misaligned from the alignment axis, the total amount of light incident to the light receiving unit 500 is changed or the distance between the reflective surface and the light receiving unit is changed, so that the image is deformed and the actual shape and Because different or out-of-proportion distortions occur. The light receiving unit 500 according to the embodiment senses the amount of light incident to the light receiving unit 500 in real time, and after determining the shape and proportion of the reflected object, the VCSEL 100, the beam splitter 300 and the aspherical reflector ( 600) The amount of light in a perfectly aligned state and the shape and proportion of the reflected object can be compared to determine the amount of alignment error of the beam splitter. The non-rotational 360-degree lidar optical system according to the embodiment may check according to the amount of alignment error and realign the beam splitter.

3 is a view showing the components of the non-rotation 360 degree lidar optical system according to the embodiment.

Referring to FIG. 3, the aspherical reflector (a) of the non-rotating 360 degree lidar optical system rotates 360 degrees by the rotational force of the rotating device, and a conical reflective surface that reflects the laser emitted from the VCSEL; includes

The beam splitter (c) is a reflector or other optical device that reflects part of the light beam and transmits the other part, and reflects the reflected light entering the aspherical reflector to the light receiver. The light receiving unit b may include a photodiode and an APD array. The APD array converts an optical signal into an electrical signal using the avalanche phenomenon. The VCSEL(d) may radiate a laser to an aspherical reflector as a light source, irradiate the VCSEL to the aspherical reflector, and receive reflected light reflected in the surrounding environment through a beam splitter to a light receiver. In the embodiment, the VCSEL(d) may be composed of a plurality of laser diodes and multicast listener discovery (MLD), and the multicast listener discovery (MLD) is used to manage a specific group when performing multicast of the diode layer. protocol can be used.

4 is a diagram illustrating an additional configuration of a VCSEL according to an embodiment.

The VCSEL according to the embodiment is an aspherical reflector, and in order to radiate a laser to a wider area, a lens and a microlens array may be additionally configured to extend the incident angle of the laser.

Hereinafter, a non-rotational 360-degree scanning method of the lidar optical system will be described in turn. Since the operation (function) of the 360-degree non-rotational scanning method of the lidar optical system according to the embodiment is essentially the same as the function on the non-rotational 360-degree lidar optical system, the description overlapping with FIGS. 1 to 4 will be omitted.

5 is a diagram illustrating a data processing flow of a 360-degree non-rotational scanning method of a lidar optical system according to an embodiment.

In step S100, a VCSEL (Vertical-Cavity Surface-Emitting Laser) emits a laser for 3D environment scanning. In step S100, in order to radiate the laser in all directions, the laser may be irradiated with a lens and a micro lens array.

In step S200, the aspherical reflector connected to the rotating device reflects the laser emitted from the VCSEL, and in step S300, the reflected light reflected from the aspherical reflector in the beam splitter is collected. In step S400, the light receiver receives the reflected light reflected from the beam splitter.

In the embodiment, in step S200, on the left and right reflective surfaces of the aspherical reflector 600, the on-off relationship of the sensors in the alignment detection sensors 61, 62, 63, and 64 for detecting the alignment of the aspherical reflector and the VCSEL or the reflective surface on which the laser is incident The alignment relationship between the VCSEL 100 and the aspherical reflector 600 may be calculated by grasping the position of and the amount of laser incident to each sensor.

The 360-degree non-rotational scanning method of the lidar optical system according to the embodiment may further include confirming the alignment relationship and the center line of the aspherical reflector, the beam splitter, and the VCSEL through a collimation lens. collimation lenses in embodiments; may be composed of multiple Avalanche Photo Diode (APD) arrays.

In addition, in the step S400 according to the embodiment, the optical axis alignment of the VCSEL, the beam splitter, and the aspherical reflector with respect to the central axis of the aspherical reflector in the light receiver is misaligned or the alignment error is detected when the alignment is off by more than a certain level. According to the direction and level of the error, the received light can be post-corrected, or the VCSEL, the beam splitter, and the aspherical reflector can be rearranged according to the error amount. For example, when the VCSEL 100 is biased to the right, more light is irradiated to the right than to the left from the aspherical reflector, so by sensing the deflected amount of irradiation, which components of the non-rotating 360-degree lidar optical system are misaligned by how much, Make it possible to realign the misaligned components according to the amount of error identified.

6 is a view showing an example of use of the non-rotation 360 degree lidar optical system according to the embodiment.

6 shows an example in which the 360-degree non-rotational lidar optical system according to the embodiment is installed at an elevated price and used for monitoring a vehicle traveling in a passing lane. Referring to FIG. 6 , in the embodiment, a rotating device connected to the reflector part of the non-rotating 360 degree lidar optical system is installed at a high price, and the aspherical reflector is rotated by the rotating device, and the surroundings can be scanned 360 degrees. That is, in the embodiment, not the rotation of the laser device itself, but the rotation of the scanning mechanism composed of a tetrahedral cube having a reflective surface. Through this, the non-rotational 360-degree lidar optical system and the non-rotational 360-degree scanning method of the lidar optical system according to the embodiment do not require rotation of the laser device itself, so peripheral scanning is possible without supplying power to the system, thereby increasing the scanning speed. and improve the circuit integration efficiency of the lidar optical system. In addition, since the aspherical reflector, which is the scanning mechanism according to the embodiment, can be rotated at a high speed with a small force, by increasing the number of scanning, it is possible to more precisely grasp the change in the motion of the surrounding object in a short time.

The disclosed content is merely an example, and can be variously changed and implemented by those skilled in the art without departing from the gist of the claims claimed in the claims, so the protection scope of the disclosed content is limited to the specific It is not limited to an Example.

Claims (8)

In the non-rotating 360 degree lidar optical system,
VCSELs (Vertical-Cavity Surface-Emitting Lasers) that emit lasers for scanning the three-dimensional environment;
an aspherical reflector connected to the rotating device and reflecting the laser emitted from the VCSEL;
a beam splitter for reflecting the reflected light reflected from the aspherical reflector to a light receiving unit;
the light receiving unit for receiving the reflected light reflected from the beam splitter;
a left alignment detection sensor installed on the left reflective surface of the aspherical reflector;
a right alignment sensor installed on the right reflective surface of the aspherical reflector; includes
The aspherical reflector, the beam splitter and the VCSEL are
aligned with the optical axis, which is the central axis of the aspherical reflector,
The aspherical reflector;
a conical reflective surface that rotates 360 degrees by a rotating device and reflects the laser emitted from the VCSEL; including,
The left and right alignment detection sensors,
When the alignment of the VCSEL and the aspherical reflector is normal, it is in an off state,
If the detected laser incident amount is different from the incident amount in the alignment state of the VCSEL and the aspherical reflector, it is determined that the alignment relationship is out of line,
When the VCSEL and the aspherical reflector are out of alignment,
When deflecting to the left, the left alignment detection sensor is in an on state and the right alignment detection sensor is in an off state,
LiDAR optical system, characterized in that the right alignment detection sensor is in an on state and the left alignment detection sensor is in an off state when deflecting to the right.
delete The method of claim 1, wherein the VCSEL is
A non-rotating 360 degree lidar optical system, characterized in that the laser is irradiated with a lens and a micro lens array to expand the angle of view of an aspherical reflector.
The apparatus of claim 1, further comprising: the beam splitter; Is
disposed between the VCSEL and the aspherical reflector,
It includes a reflective surface that reflects the laser and a transmissive surface that transmits the laser,
The reflective surface is inclined at a predetermined angle with respect to the optical axis so that the laser reflected from the aspherical reflector proceeds to the light receiving unit,
The transmissive surface is disposed perpendicular to the optical axis so that the laser emitted from the VCSEL proceeds to the aspherical reflector.

delete delete delete delete

Images