KR20240052420A - Lidar device of coaxial structure - Google Patents

Abstract

A lidar device with a coaxial structure that can improve the light reception efficiency of laser light reflected by an external object is provided. The LiDAR device can split and provide reflected laser light received from the outside through a light receiving unit and a polarization separator to each of two detection units so that external objects can be detected through each detection unit.

Description

Lidar device of coaxial structure}

The present invention relates to a lidar device with a coaxial structure that can improve the light reception efficiency of laser light received after being reflected by an external object.

LIDAR (Light Detection And Ranging; LIDAR) devices are used to measure objects (targets) such as surrounding terrain, objects, and obstacles. This LiDAR device uses a pulsed laser to measure the time it takes to reflect from an object and return to obtain information about the object. Information about an object obtained through a LIDAR device includes information about the existence of the object, the type of the object, and the distance to the object.

LiDAR devices are used in various fields such as automobiles, mobile robots, ships, security systems, assembly lines, unmanned aerial vehicles, drones, etc., and their field of use is expanding in various fields.

The LiDAR device has an optical structure that collects the diffused beam output from a high-power laser diode through a light transmitting lens and outputs it to the outside, and receives light reflected from an object through a light receiving lens and detects it with a detector.

These LiDAR devices can be divided into coaxial and biaxial structures depending on the method of transmitting and receiving laser light. Among these, the coaxial structure LiDAR device transmits and receives light on the same axis, so the light transmitting and receiving axes of the laser coincide, which is advantageous for miniaturization, and has the advantage of equalizing the amount of incident light from the light receiving lens according to the angle of view. there is.

However, in the coaxial structure of the LiDAR device, a path through which the externally output laser passes must be formed in the light receiving lens, so the amount of light provided to the detector through the light receiving lens is reduced depending on the object position, thereby lowering the accuracy of object recognition. There is a problem that the maximum detectable distance is reduced.

In other words, the beam size of the laser reflected from an object located at a short distance becomes small, and because of this, in the conventional coaxial structure LiDAR device, the laser reflected from the object and received passes through the passage formed in the light receiving lens, resulting in loss. .

Accordingly, in the conventional coaxial structure LiDAR device, the amount of laser light provided from the light receiving lens to the detector is reduced, which reduces the accuracy of object recognition and distance detection using the LiDAR device, and reduces the maximum detectable distance.

Korean Patent Publication No. 10-2022-0080350 (2022.06.14.)

The purpose of the present invention is to provide a LiDAR device with a coaxial structure that can improve the light reception efficiency of laser light received after being reflected by an external object.

A lidar device having a coaxial structure according to an embodiment of the present invention includes a light source that generates laser light; Outputs the laser light to the outside, receives reflected laser light reflected from an external object with respect to the laser light, passes some of the reflected laser light among the received reflected laser light, and passes the remaining reflected laser light through one side. A light receiving unit for re-reflection; It is disposed between the light source and the light receiving unit, transmits the laser light and outputs it to the outside through the light receiving unit, and transmits the reflected laser light of the first polarization among the partially reflected laser light that has passed through the light receiving unit to a first optical path. a polarization separator for outputting a second polarized laser light among the partially reflected laser light and reflecting the reflected laser light to a second optical path; a first detection unit disposed on one side of the light receiving unit and receiving and detecting the remaining reflected laser light re-reflected from the light receiving unit; and a second detection unit disposed on one side of the polarization separation unit and receiving and detecting the laser light of the second polarization reflected from the polarization separation unit.

At this time, the coaxial lidar device of this embodiment outputs the final detection result for the object by adding the output of the first detector and the output of the second detector.

Here, the light receiving part has one surface formed of a concave mirror, and a hole through which the laser light and part of the reflected laser light passes is formed in the central part.

In addition, the light receiving unit has one surface formed of a flat mirror, and a hole through which the laser light and part of the reflected laser light passes is formed in the central part.

Additionally, the light receiving unit is a prism with a reflective surface formed in the direction of the polarization separator to re-reflect the laser light and some of the reflected laser light.

In addition, the LiDAR device of this embodiment further includes a phase delay unit disposed between the polarization separator and the light receiving unit to generate a phase difference in each of the laser light and the partially reflected laser light.

Here, the phase delay unit is a quarter-wave plate.

The first detection unit includes a first filter that transmits the remaining reflected laser light re-reflected from the light receiving unit; And a first lidar sensor that receives the remaining reflected laser light that has passed through the first filter and generates a three-dimensional depth map for the object.

In addition, the first detection unit is a first condensing lens disposed between the first filter and the first lidar sensor and concentrating the remaining reflected laser light that has passed through the first filter onto the first lidar sensor. It further includes.

The second detection unit includes a second filter that transmits the reflected laser light of the second polarization output from the polarization separator to the second optical path; a second condenser lens that focuses the reflected laser light of the second polarization that has passed through the second filter; And a second lidar sensor that generates a three-dimensional depth map for the object by receiving the reflected laser light of the second polarization condensed by the second condenser lens.

Additionally, the reflected laser light of the first polarization has the same polarization state as the laser light.

The LiDAR device of the present invention divides the reflected laser light received from the outside through the light receiving unit and the polarization splitter and provides it to each of the two detection units, thereby enabling detection of external objects through each detection unit.

Therefore, the LiDAR device of the present invention can increase light receiving efficiency by preventing loss of reflected laser light received from the outside, thereby increasing the accuracy of object recognition and improving the accuracy of distance detection and 3D depth map generation. And the maximum detectable distance of the LIDAR device can be increased.

Figure 1 is a block diagram of a coaxial LiDAR device of the present invention.
Figure 2 is a diagram showing an optical output path in a coaxial LiDAR device according to an embodiment of the present invention.
FIG. 3 is a diagram showing a light reception path in the coaxial structure LiDAR device of FIG. 2.
Figure 4 is a diagram showing a light reception path in a coaxial LiDAR device according to another embodiment of the present invention.
Figure 5 is a diagram showing an optical output path in a coaxial LiDAR device according to another embodiment of the present invention.
FIG. 6 is a diagram showing a light reception path in the coaxial structure LiDAR device of FIG. 5.
Figure 7 is a diagram showing the output of the coaxial structure LiDAR device of the present invention.

The advantages and features of the present invention and methods for achieving them will become clear by referring to the embodiments described in detail below along with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below and may be implemented in various different forms. The present embodiments are merely provided to ensure that the disclosure of the present invention is complete and to be understood by those skilled in the art in the technical field to which the present invention pertains. It is provided to fully inform those who have the scope of the invention, and the present invention is only defined by the scope of the claims.

In describing embodiments of the present invention, if a detailed description of a known function or configuration is judged to unnecessarily obscure the gist of the present invention, the detailed description will be omitted. The terms described below are defined in consideration of functions in the embodiments of the present invention, and may vary depending on the intention or custom of the user or operator. Therefore, the definition should be made based on the contents throughout this specification.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings.

Figure 1 is a block diagram of a coaxial LiDAR device of the present invention.

Referring to FIG. 1, the LIDAR device 100 of this embodiment may include a light source 110, an optical module, and a detection module. Here, the optical module may include a polarization separator 120, a phase delay unit 130, a light receiving unit 140, and a spatial scanner 150. The detection module may include a first detection unit 160 and a second detection unit 170.

In addition, the LiDAR device 100 of this embodiment is a LiDAR with a coaxial structure in which the optical axis of the light output from the light source 110 and the optical axis of the light incident on the polarization separator 120 or phase delay unit 130 of the optical module are the same. It may be device 100.

The light source 110 may generate and output single-polarized laser light in the form of a pulse having a predetermined wavelength. For example, the light source 110 may generate and output one of monopolarized P-wave laser light and S-wave laser light. Here, the P wave may refer to light that vibrates vertically based on the incident surface, and the S wave may refer to light that vibrates parallel to the incident surface.

This light source 110 includes a light source (not shown) that generates laser light, a collimating lens (not shown) that ensures that the laser light output from the light source is parallel without being dispersed, and a laser that passes through the collimating lens. It may include a beam shaping optics (not shown) that expands the beam size of light and outputs it, and a relay lens (not shown) that inputs the expanded size laser light into the polarization separator 120, which will be described later. You can.

The polarizing beam splitter (120) of the optical module may have a cube shape in which two prisms formed of birefringent crystals are bonded together, and a representative example may be a Wollaston prism, but is not limited thereto.

The polarization separator 120 may convert the optical path of the incident light by reflecting light of a specific polarization among the incident light and transmitting the remaining light except for the light of the specific polarization.

For example, the polarization separator 120 may transmit the single-polarization laser light output from the light source 110 and output it to the outside.

In addition, the polarization separator 120 receives reflected laser light reflected by an external object 10 in response to the laser light output to the outside, and transmits a portion of the reflected laser light according to the polarization state to the first optical path. It can be output, and the rest can be re-reflected and output through the second optical path. Here, the reflected laser light output through the first optical path by the polarization separator 120 may have the same polarization state as the laser light generated by the light source 110.

The phase delay unit 130 of the optical module may be disposed between the polarization separator 120 and the light receiving unit 140. The phase delay unit 130 may generate and output a predetermined phase difference, for example, a phase difference of 1/4λ, in the laser light output from the polarization separator 120. Additionally, the phase delay unit 130 may generate a phase difference of 1/4λ in the reflected laser light received from the outside and output it to the polarization separator 120. This phase delay unit 130 may be a quarter-wave plate, but is not limited thereto.

Meanwhile, the phase delay unit 130 of this embodiment can change the wavelength of the reflected laser light reflected and received by the object 10 to change the polarization.

For example, first polarization by single polarization, for example, laser light of P wave component may be output from the light source 110. The polarization separator 120 transmits the laser light of the first polarization and outputs it to the phase delay unit 130, and the phase delay unit 130 generates a phase difference of 1/4λ in the laser light of the first polarization and outputs it. You can.

When the laser light of the first polarization is output to the outside, it is reflected by the object 10 and reflected laser light may be received. This reflected laser light may include reflected laser light of a first polarization including a P-wave component and reflected laser light of a second polarization including an S-wave component.

At this time, the phase delay unit 130 generates a phase difference of 1/4λ in the reflected laser light, which may cause the polarization of the reflected laser light to change. In other words, since the laser light of the first polarization output to the outside generates a phase difference of 1/4λ, the reflected laser light reflected by the object 10 and received may also generate a phase difference of 1/4λ. When this reflected laser light is received and input to the phase delay unit 130, a phase difference of 1/4λ may be generated again by the phase delay unit 130. As a result, the polarization state of the reflected laser light of the first polarization among the reflected laser lights is converted to the reflected laser light of the second polarization, and the polarization state of the reflected laser light of the second polarization is converted to the reflected laser light of the first polarization. You can.

Meanwhile, when the external object 10 is a reflector such as a mirror, the reflected laser light reflected and received by the object 10 may have the same polarization state as the already output laser light.

That is, if the laser light output to the outside is first polarized laser light with a phase difference of 1/4λ, the reflected laser light received from the outside may also be reflected laser light of the first polarization with a phase difference of 1/4λ. .

This reflected laser light is input to the phase delay unit 130, and a phase difference of 1/4λ can be generated once again by the phase delay unit 130. Therefore, the polarization state of the reflected laser light of the first polarization can be converted to the reflected laser light of the second polarization.

The light receiving unit 140 of the optical module outputs the laser light output from the phase delay unit 130 to the outside through the spatial scanner 150, and transmits the reflected laser light reflected by the external object 10 to the spatial scanner 150. ) can be received through.

The light receiving unit 140 passes some of the received reflected laser light and provides it to the phase delay unit 130, and re-reflects the rest through one surface, that is, a reflective surface, and provides it to the first detection unit 160, which will be described later. .

As shown in Figures 2 and 3, the light receiving unit 140 according to an embodiment of the present invention may be a concave mirror with one surface, that is, a reflection surface, having a concave shape. Additionally, as shown in FIG. 4, the light receiving unit 141 according to another embodiment of the present invention may be a flat mirror whose reflecting surface is in the shape of a flat plate.

In addition, as shown in FIGS. 2 to 4, the light receiving units 140 and 141 receive some reflected laser light among the laser light LR1 output from the phase delay unit 130 and the reflected laser light LR2 received from the outside. , for example, holes 145 and 146 through which the first reflected laser light LR2-1 can pass may be formed. At this time, the remaining reflected laser light (LR2), for example, the second reflected laser light (LR2-2), may be re-reflected by one surface of the light receiving units 140 and 141, that is, the reflecting surface.

Therefore, among the reflected laser light LR2 received by the light receiving units 140 and 141, the first reflected laser light LR2-1 is provided to the phase delay unit 130 through the holes 145 and 146, and the second reflected laser light LR2-1 is provided to the phase delay unit 130 through the holes 145 and 146. The laser light LR2-2 may be re-reflected by the reflective surface and provided to the first detection units 160 and 160' of the detection module.

Additionally, as shown in FIGS. 5 and 6, the light receiving unit 142 according to another embodiment of the present invention may be a prism with a reflective surface formed in the direction of the phase delay unit 130. Here, the light receiving unit 142, or prism, of this embodiment may be formed in a size smaller than one surface of the spatial scanner 150.

Accordingly, among the reflected laser light LR2 output from the spatial scanner 150, the first reflected laser light LR2-1 is re-reflected by the reflective surface of the light receiving unit 142 and provided to the phase delay unit 130, The second reflected laser light LR2-2 may be provided to the first detection unit 160' through both sides of the light receiving unit 142.

Referring again to FIG. 1, the spatial scanner 150 of the optical module adjusts the direction of the laser light provided through the light receiving unit 140 within a preset angle range in up and down/left and right directions, for example, in the x-axis and y-axis directions. It can be output externally. In addition, the spatial scanner 150 can adjust the direction of the reflected laser light reflected and received from the external object 10 within a preset angle range in the up and down/left and right directions and output it to the light receiving unit 140.

The first detector 160 of the detection module is disposed on one side of the light receiver 140, and detects the distance to the external object 10 by receiving reflected laser light from the light receiver 140 or the spatial scanner 150. , Accordingly, a 3D depth map for the object 10 can be generated.

Here, as shown in FIGS. 3 and 4, when the light receiving units 140 and 141 are concave mirrors or flat mirrors, the first detection units 160 and 160' are located on the reflecting surfaces of the light receiving units 140 and 141. The second reflected laser light (LR2-2) that is re-reflected can be received. In addition, as shown in FIG. 6, when the light receiving unit 142 is in the form of a prism, the first detection unit 160' is a second reflection laser provided from the space scanner 150 through both sides of the light receiving unit 142. Light (LR2-2) can be received.

This first detection unit 160 may include a first filter 161 and a first lidar sensor 165.

The first filter 161 may be a band-pass filter that passes the wavelength band of the laser light among the light provided by being re-reflected from the light receiving unit 140. Accordingly, the first filter 161 can pass the second reflected laser light.

The first LIDAR sensor 165 receives the second reflected laser light that has passed through the first filter 161 to detect the distance to the external object 10, and accordingly detects the three-dimensional You can create a depth map.

In addition, according to an embodiment of the present invention, the first detection unit 160' may further include a first condenser lens 163 disposed between the first filter 161 and the first lidar sensor 165. . The first condenser lens 163 can collect the second reflected laser light that has passed through the first filter 161 and provide it to the first lidar sensor 165.

Here, the first condensing lens 163 may be included in the first detection unit 160' when the light receiving units 141 and 142 are in the form of a flat mirror or a prism, as shown in FIGS. 4 and 5. On the other hand, as shown in FIG. 2, when the light receiving unit 140 is in the form of a concave mirror, the reflecting surface of the light receiving unit 140 is concave, so the second reflected laser light re-reflected from the light receiving unit 140 is condensed. Since it can be provided in the first detection unit 160, the first condensing lens 163 can be omitted.

The second detection unit 170 of the detection module is disposed on one side of the polarization separation unit 120, and receives the reflected laser light of the second polarization that is re-reflected by the polarization separation unit 120 and output to the second optical path. Thus, the distance to the external object 10 is detected, and a 3D depth map for the object 10 can be generated accordingly.

This second detection unit 170 may include a second filter 171, a second converging lens 173, and a second lidar sensor 175.

The second filter 171 may be a band-pass filter that passes the wavelength band of the laser light among the light provided from the polarization separator 120. Accordingly, the second filter 171 can pass the reflected laser light of the second polarization.

The second condenser lens 173 may converge and output the reflected laser light of the second polarization that has passed through the second filter 171.

The second LIDAR sensor 175 detects the distance to the external object 10 by receiving the reflected laser light of the second polarization collected by the second condenser lens 173, and accordingly detects the distance to the object 10 You can create a 3D depth map for .

In this way, each of the first detection unit 160 and the second detection unit 170 of the detection module receives divided reflected laser light reflected from the external object 10 through the optical module and receives the reflected laser light from these reflected laser lights. It is possible to recognize an external object 10, detect the distance, and generate a 3D depth map.

Accordingly, the LIDAR device 100 of this embodiment can increase detection accuracy for the object 10 by matching and adding the signal output from the first detection unit 160 and the signal output from the second detection unit 170. And, the detection distance of the object 10 can be increased.

As shown in (a) of FIG. 7, the first detection unit 160 may output a first signal DS1 of a predetermined amplitude from reflected laser light provided through an optical module. Additionally, as shown in (b) of FIG. 7, the second detection unit 170 may output a second signal DS2 of a predetermined amplitude from the reflected laser light provided through the optical module. Accordingly, as shown in (c) of FIG. 7, the LIDAR device 100 of this embodiment matches and adds the first signal DS1 and the second signal DS2, and then As a result of the detection, for example, a sum signal DSt including the distance of the object 10 and a 3D depth map may be output.

Here, the summed signal DSt finally output from the LIDAR device 100 appears as the sum of the amplitude of the first signal DS1 and the amplitude of the second signal DS2. Therefore, the LIDAR device 100 of the present invention can not only increase the accuracy of distance detection and 3D depth map generation for an external object 10, but also increase the maximum detectable distance for the object 10. You can.

Meanwhile, in order to accurately match the first signal DS1 output from the first detection unit 160 and the second signal DS2 output from the second detection unit 170, the first detection unit 160 and the second detection unit ( 170), specifically, the first lidar sensor 165 of the first detection unit 160 and the second lidar sensor 175 of the second detection unit 170 are connected to the external object 10, the light receiving unit 140, and They may be arranged to have the same distance, that is, the same optical path, based on at least one of the polarization separators 120.

In this way, the LiDAR device 100 of the present invention divides the reflected laser light reflected and received from the external object 10 through the light receiving unit 140 and the polarization separator 120 to generate the first detection unit 160 and the polarization separation unit 120. It can be provided to each of the second detection units 170, detect the distance and generate a 3D depth map for the object 10 through each detection unit 160 and 170, and then match and add them to output as the final result. .

Accordingly, the lidar device 100 of the coaxial structure of the present invention prevents the reflected laser light reflected and received by the object 10 from being lost by the light receiving unit 140 and reducing the light receiving efficiency, thereby The accuracy of distance detection and 3D depth map generation can be improved, and the maximum detectable distance for the object 10 can be increased.

In addition, the lidar device 100 of the coaxial structure of the present invention detects the reflection reflected by the object 10 through the phase delay unit 130 even if the external object 10 is a reflector that maintains the polarization of the output laser light. By changing the polarization state of the laser light, loss of reflected laser light by the polarization separator 120 can be prevented.

FIG. 2 is a diagram showing an optical output path in a coaxial LiDAR device according to an embodiment of the present invention, and FIG. 3 is a diagram illustrating an optical reception path in the coaxial LiDAR device of FIG. 2 .

First, referring to FIG. 2, in the lidar device 100 of the coaxial structure of this embodiment, the light source 110 generates a single polarized laser light, for example, a laser light LR1 of the first polarization having a P wave component. You can.

The laser light LR1 of the first polarization output from the light source 110 is provided to the polarization separator 120, and the polarization separator 120 transmits all of the laser light LR1 of the first polarization to the phase delay unit. It can be output as (130).

The phase delay unit 130 may generate a phase difference of 1/4λ in the laser light LR1 of the first polarization provided from the polarization separator 120 and output this to the light receiving unit 140.

The light receiving unit 140 may be a concave mirror having a concave reflection surface. A hole 145 through which laser light passes may be formed in this light receiving unit 140. Accordingly, the laser light LR1 of the first polarization output from the phase delay unit 130 may pass through the hole 145 of the light receiving unit 140 and be provided to the spatial scanner 150.

The spatial scanner 150 may output the first polarized laser light LR1 to the outside by adjusting the direction of the light within a preset angle range.

In addition, referring to FIG. 3, the laser light of the first polarization output to the outside is reflected by the object 10, and the spatial scanner 150 of the LIDAR device 100 is reflected by the object 10. Laser light (LR2) can be received. The spatial scanner 150 can adjust the direction of the reflected laser light LR2 within a preset angle range and output it to the light receiving unit 140.

Here, the reflected laser light LR2 may include reflected laser light of the P wave component, that is, reflected laser light of the first polarization, and reflected laser light of the S wave component, that is, reflected laser light of the second polarization.

Some of the reflected laser light LR2 provided to the light receiving unit 140, that is, the first reflected laser light LR2-1, passes through the light receiving unit 140 through the hole 145 of the light receiving unit 140 and passes through the phase delay unit ( 130). Additionally, the remainder of the reflected laser light LR2, that is, the second reflected laser light LR2-2, may be re-reflected by the reflective surface of the light receiving unit 140 and provided to the first detection unit 160.

The first detector 160 receives the second reflected laser light LR2-2 provided from the light receiver 140, detects the distance to the object 10, and creates a three-dimensional depth map for the object 10 accordingly. can be created.

Here, since the light receiving unit 140 of this embodiment is in the form of a concave mirror with a concave reflection surface, the second reflected laser light LR2-2 can be focused and provided to the first detection unit 160. Accordingly, the first detection unit 160 of this embodiment may be configured to include a first filter 161 and a first lidar sensor 165.

In addition, the phase delay unit 130 generates a phase difference of 1/4λ in the first reflected laser light LR2-1 that has passed through the hole 145 of the light receiving unit 140, thereby reducing the first reflected laser light LR2-1. ) can be converted to polarization. The phase delay unit 130 may output the first reflected laser light (LR2-1) whose polarization has been converted to the polarization separator 120.

For example, since the first polarized laser light LR1 output to the outside is light with a phase difference of 1/4λ generated by the phase delay unit 130, the reflected laser light LR2 reflected by the object 10 is also light. It may be light in which a phase difference of 1/4λ is generated. Accordingly, when the first reflected laser light (LR2-1) of the reflected laser light (LR2) with a phase difference of 1/4λ is provided to the phase delay unit 130, the phase delay unit 130 once again provides 1 A phase difference of /4λ may occur. As a result, the reflected laser light of the first polarization among the first reflected laser light (LR2-1) is converted into the reflected laser light of the second polarization, and the reflected laser light of the second polarization is converted into the reflected laser light of the first polarization. Polarization can be converted.

The polarization separator 120 transmits the reflected laser light of the first polarization among the first reflected laser light (LR2-1) provided through the phase delay unit 130 and outputs it through the first optical path, and reflects the second polarized light. The laser light can be reflected again and output through a second optical path.

The second detection unit 170 receives the reflected laser light of the second polarization output from the polarization separator 120 to the second optical path, detects the distance to the object 10, and detects the distance to the object 10 accordingly. A 3D depth map can be created.

Here, since the reflected laser light of the second polarization output from the polarization separator 120 is output in the form of a parallel beam, the second detection unit 170 includes the second filter 171, the second converging lens 173, and the second converging lens 173. It may be configured to include 2 lidar sensors 175. The second condenser lens 173 may collect the reflected laser light of the second polarization that has passed through the second filter 171 and provide it to the second lidar sensor 175.

Additionally, as described above, the LIDAR device 100 of this embodiment may add the output of the first detector 160 and the output of the second detector 170 and output the final result. Figure 4 is a diagram showing a light reception path in a coaxial LiDAR device according to another embodiment of the present invention.

The LiDAR device 101 shown in FIG. 4 is composed of a flat mirror in which the reflecting surface of the light receiving unit 141 has a flat plate shape, compared to the LiDAR device 100 previously described with reference to FIGS. 2 and 3, Accordingly, they are substantially the same except that the first condensing lens 163 is included in the first detection unit 160'. Accordingly, like members are denoted by like symbols and detailed description thereof will be omitted.

In addition, although not shown in FIG. 4, the path through which the laser light of the first polarization generated by the light source 110 in the LiDAR device 101 of this embodiment is output to the outside is substantially the same as that described above with reference to FIG. 2. Therefore, description thereof is omitted.

Referring to FIG. 4, the laser light of the first polarization output to the outside is reflected by the object 10, and the spatial scanner 150 receives the reflected laser light LR2 reflected by the object 10 and The direction of light can be adjusted within a set angle range and then output to the light receiving unit 141.

Among the reflected laser lights LR2 provided to the light receiving unit 141, the first reflected laser light LR2-1 passes through the hole 146 of the light receiving unit 141 to the phase delay unit 130. can be provided. Additionally, the second reflected laser light LR2-2 of the reflected laser light LR2 may be re-reflected by the reflective surface of the light receiving unit 141 and provided to the first detection unit 160'.

The first detector 160' receives the second reflected laser light LR2-2 provided from the light receiver 141, detects the distance to the object 10, and creates a three-dimensional depth map of the object 10 accordingly. can be created.

Here, since the light receiving unit 141 of this embodiment is in the form of a flat mirror with a flat reflection surface, the first detection unit 160' includes the first filter 161, the first converging lens 163, and the first lidar sensor 165. ) may be configured to include. Accordingly, the second reflected laser light LR2-2 condensed by the first converging lens 163 may be provided to the first lidar sensor 165.

In addition, the phase delay unit 130 generates a phase difference of 1/4λ in the first reflected laser light LR2-1 passing through the hole 146 of the light receiving unit 141, thereby reducing the first reflected laser light LR2-1. ) can be converted to polarization. The phase delay unit 130 may output the first reflected laser light (LR2-1) whose polarization has been converted to the polarization separator 120.

The polarization separator 120 transmits the reflected laser light of the first polarization among the first reflected laser light (LR2-1) provided through the phase delay unit 130 and outputs it through the first optical path, and reflects the second polarized light. The laser light can be reflected again and output through a second optical path.

The second detection unit 170 receives the reflected laser light of the second polarization output from the polarization separator 120 to the second optical path, detects the distance to the object 10, and detects the distance to the object 10 accordingly. A 3D depth map can be created.

Additionally, the LIDAR device 101 of this embodiment may add the output of the first detector 160' and the output of the second detector 170 and output the final result.

FIG. 5 is a diagram showing an optical output path in a lidar device having a coaxial structure according to another embodiment of the present invention, and FIG. 6 is a diagram showing a light receiving path in the lidar device having a coaxial structure of FIG. 5 .

First, referring to FIG. 5, in the lidar device 102 having a coaxial structure of this embodiment, the light source 110 may generate laser light LR1 of the first polarization.

The laser light LR1 of the first polarization output from the light source 110 is provided to the polarization separator 120, and the polarization separator 120 transmits all of the laser light LR1 of the first polarization to the phase delay unit. It can be output as (130).

The phase delay unit 130 may generate a phase difference of 1/4λ in the laser light LR1 of the first polarization provided from the polarization separator 120 and output this to the light receiving unit 142.

The light receiving unit 142 may be a prism whose reflective surface is arranged to correspond to the optical path of the first polarized laser light LR1 output from the phase delay unit 130. Accordingly, the laser light LR1 of the first polarization output from the phase delay unit 130 may be re-reflected by the reflective surface of the light receiving unit 142 and provided to the spatial scanner 150.

In this way, the light receiving unit 142 of this embodiment is composed of a prism with a reflective surface formed on one side, so that there is no need to form a hole through which the laser light passes through the light receiving unit 142, thereby increasing the convenience of manufacturing the light receiving unit 142.

The spatial scanner 150 can output the first polarized laser light LR1 to the outside by adjusting the direction of the light within a preset angle range.

Referring to FIG. 6, the laser light of the first polarization output to the outside is reflected by the object 10, and the spatial scanner 150 of the LIDAR device 102 detects the reflected laser light reflected by the object 10. (LR2) can be received. The spatial scanner 150 can adjust the direction of the reflected laser light LR2 within a preset angle range and output it to the light receiving unit 142.

Here, the reflected laser light LR2 may include reflected laser light of the first polarization and reflected laser light of the second polarization.

Some of the reflected laser light LR2 provided to the light receiving unit 142, that is, the first reflected laser light LR2-1, may be re-reflected by the reflective surface of the light receiving unit 142 and provided to the phase delay unit 130. . Additionally, the remainder of the reflected laser light LR2, that is, the second reflected laser light LR2-2, may be provided to the first detection unit 160' through both sides of the light receiving unit 142.

At this time, as described above, since the light receiving unit 142 has a smaller size than one side of the spatial scanner 150, the second reflected laser light LR2-2 is transmitted to both sides of the light receiving unit 142 without interference from the light receiving unit 142. It can be provided to the first detection unit 160' through.

The first detector 160' may receive the second reflected laser light LR2-2, detect the distance to the object 10, and generate a three-dimensional depth map for the object 10 accordingly. This first detection unit 160' may include a first filter 161, a first converging lens 163, and a first lidar sensor 165.

In addition, the phase delay unit 130 generates a phase difference of 1/4λ in the first reflected laser light (LR2-1) provided by being re-reflected from the light receiving unit 142, thereby polarizing the first reflected laser light (LR2-1). can be converted. The phase delay unit 130 may output the first reflected laser light (LR2-1) whose polarization has been converted to the polarization separator 120.

The polarization separator 120 transmits the reflected laser light of the first polarization among the first reflected laser light (LR2-1) provided through the phase delay unit 130 and outputs it through the first optical path, and reflects the second polarized light. The laser light can be reflected again and output through a second optical path.

The second detection unit 170 receives the reflected laser light of the second polarization output from the polarization separator 120 to the second optical path, detects the distance to the object 10, and detects the distance to the object 10 accordingly. A 3D depth map can be created. The second detection unit 170 may be configured to include a second filter 171, a second condenser lens 173, and a second lidar sensor 175.

Additionally, the LIDAR device 102 of this embodiment may add the output of the first detector 160' and the output of the second detector 170 and output the final result.

As described above, the LiDAR devices 100, 101, and 102 according to various embodiments of the present invention receive reflected laser light from the outside through the light receiving units 140, 141, 142 and the polarization separation unit 120. A part of LR2) is provided to the first detection units 160 and 160' to detect the object 10, and the remainder of the reflected laser light LR2 is provided to the second detection unit 170 to detect the object 10. It can be detected.

Then, the LIDAR devices 100, 101, and 102 match and add the output of the first detectors 160 and 160' and the output of the second detector 170, and use the summed signal as the final signal for the object 10. It can be output as a detection result.

Therefore, the LiDAR devices 100, 101, and 102 of the present invention can increase light reception efficiency by preventing loss of reflected laser light LR2 received from the outside, thereby accurately detecting the external object 10. Distance detection and accurate three-dimensional depth maps can be generated, and the maximum detectable distance for an object 10 can be increased.

The above description is merely an illustrative explanation of the technical idea of the present invention, and those skilled in the art will be able to make various modifications and variations without departing from the essential quality of the present invention. Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention, but are for illustrative purposes, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention shall be interpreted in accordance with the claims below, and all technical ideas within the scope equivalent thereto shall be construed as being included in the scope of rights of the present invention.

The LiDAR device according to an embodiment of the present invention can split the laser light reflected by an external object and detect the object through each of two detection units. Therefore, the LiDAR device of the present invention can prevent the loss of received laser light, thereby increasing the recognition accuracy of the object that is the detection target, and thereby increasing the accuracy of detecting the distance to the object and generating a 3D depth map. The lidar device of the present invention can be used in control systems or security systems and their related technical fields.

100, 101, 102: LiDAR device
110: light source
120: Polarization separation unit
130: Phase delay unit
140, 141, 142: light receiving unit
150: Space scanner
160: First detection unit
170: Second detection unit

Claims (10)

A light source that generates laser light;
Outputs the laser light to the outside, receives reflected laser light reflected from an external object with respect to the laser light, passes some of the reflected laser light among the received reflected laser light, and passes the remaining reflected laser light through one side. A light receiving unit that re-reflects;
It is disposed between the light source and the light receiving unit, transmits the laser light and outputs it to the outside through the light receiving unit, and transmits the reflected laser light of the first polarization among the partially reflected laser light that has passed through the light receiving unit to a first optical path. a polarization separator for outputting a second polarized laser light among the partially reflected laser light and reflecting the reflected laser light to a second optical path;
a first detection unit disposed on one side of the light receiving unit and receiving and detecting the remaining reflected laser light re-reflected from the light receiving unit; and
A second detection unit disposed on one side of the polarization separator and receiving and detecting the laser light of the second polarization reflected from the polarization separator,
A lidar device with a coaxial structure that adds the output of the first detector and the output of the second detector to output a final detection result for the object. According to paragraph 1,
The light receiving unit,
A lidar device having a coaxial structure in which one surface is formed of a concave mirror and a hole through which the laser light and part of the reflected laser light passes is formed in the central portion. According to paragraph 1,
The light receiving unit,
A lidar device having a coaxial structure in which one surface is formed of a flat mirror and a hole through which the laser light and part of the reflected laser light passes is formed in the central portion. According to paragraph 1,
The light receiving unit,
A lidar device with a coaxial structure, which is a prism in which a reflective surface is formed in the direction of the polarization separator to re-reflect the laser light and some of the reflected laser light. According to paragraph 1,
A lidar device having a coaxial structure further comprising a phase delay unit disposed between the polarization separator and the light receiving unit to generate a phase difference in each of the laser light and the partially reflected laser light. According to clause 5,
The phase delay unit is a coaxial LiDAR device in which the phase delay unit is a quarter-wave plate. According to paragraph 1,
The first detection unit,
a first filter that transmits the remaining reflected laser light re-reflected from the light receiving unit;
a first condenser lens that condenses the remaining reflected laser light that has passed through the first filter; and
A lidar device with a coaxial structure including a first lidar sensor that receives the remaining reflected laser light collected by the first condenser lens and generates a three-dimensional depth map for the object. According to paragraph 1,
The second detection unit,
a second filter transmitting the reflected laser light of the second polarization output from the polarization separator to the second optical path;
a second condenser lens that focuses the reflected laser light of the second polarization that has passed through the second filter; and
A lidar device of a coaxial structure including a second lidar sensor that receives reflected laser light of the second polarization condensed by the second condenser lens and generates a three-dimensional depth map for the object. According to paragraph 1,
The first detection unit and the second detection unit,
A lidar device with a coaxial structure disposed at the same distance from at least one of the object, the light receiving unit, and the polarization separator. According to paragraph 1,
A lidar device having a coaxial structure in which the reflected laser light of the first polarization has the same polarization state as the laser light.