Laser radar

Abstract

The embodiment of the invention discloses a laser radar, which comprises a shell, a transmitter, a receiver and at least one polarization extinction module, and is characterized in that the polarization extinction module is located in a non-main light ray area, and the polarization extinction module is used for regulating and controlling the polarization state of an optical signal so as to attenuate the intensity of the optical signal emitted and / or reflected by the polarization extinction module. The polarization extinction module is located in the non-main light ray area, so that the arrangement of the polarization extinction module hardly affects the optical signals in the main light ray area, and the polarization extinction module is mainly used for processing the optical signals in the non-main light ray area. The optical signal of the non-principal ray area comprises stray light, and the polarization extinction module can regulate and control the polarization state of the stray light of the non-principal ray area so as to attenuate the intensity of the stray light emitted and / or reflected by the polarization extinction module, reduce the influence of the stray light on the detection result of the laser radar, and improve the detection precision of the laser radar.

Description

Technical Field

[0001] This application relates to the field of laser detection equipment technology, and in particular to a lidar. Background Technology

[0002] LiDAR is a radar system that uses laser beams to detect the position, velocity, and other characteristics of a target. Its working principle is to measure relevant information of the target object by transmitting laser signals through the transmitting module and receiving the echo signals detected by the receiving module. For example, parameters such as target distance, azimuth, altitude, velocity, attitude, and even shape.

[0003] Stray light exists within the lidar, and when this stray light is received by the detector, it can affect the lidar's detection results. Summary of the Invention

[0004] This application provides a lidar that addresses the problem in related technologies where stray light exists within the lidar and is received by the detector, affecting the lidar's detection results.

[0005] This application provides a lidar system, including: case; The transmitter, located inside the housing, is used to emit light. A receiver, located inside the housing, is used to receive echo light; At least one polarization extinction module is located inside the housing. The polarization extinction module is located in the non-main ray region. The polarization extinction module is used to regulate the polarization state of the light signal to attenuate the intensity of the light signal emitted and / or reflected through the polarization extinction module.

[0006] In some embodiments, the at least one polarization extinction module includes: The first polarization extinction module includes a first linear polarizer and a first quarter-wave plate distributed along the transmission direction of the optical signal.

[0007] In some embodiments, the first polarization extinction module includes: The reflector is located on the side of the first quarter-wave plate away from the first linear polarizer, along the direction of light signal transmission.

[0008] In some embodiments, the at least one polarization extinction module includes: The second polarization extinction module includes a second linear polarizer, a second polarization converter, and a third linear polarizer distributed along the transmission direction of the optical signal. The polarization direction of the third linear polarizer is parallel to the polarization direction entering the second linear polarizer. The second polarization converter is used to change the polarization state of the linearly polarized light output by the second linear polarizer.

[0009] In some embodiments, the second polarization converter includes a second quarter-wave plate, a first half-wave plate, and a third quarter-wave plate distributed along the transmission direction of the optical signal.

[0010] In some embodiments, the second polarization converter includes a second half-wave plate.

[0011] In some embodiments, the at least one polarization extinction module includes: The third polarization extinction module includes a fourth linear polarizer and a fifth linear polarizer distributed along the transmission direction of the optical signal. The polarization direction of the fourth linear polarizer is perpendicular to the polarization direction of the fifth linear polarizer, and the reflectivity of the fifth linear polarizer is less than or equal to 5%.

[0012] In some embodiments, the transmitter emits initial linearly polarized light, the polarization direction of which is parallel to the polarization directions of the first, second, and fourth linearly polarized plates.

[0013] In some embodiments, the following are included: The beam splitter, located inside the housing, includes a light-transmitting part and a reflective part connected to the light-transmitting part. The light-transmitting part is used to receive the emitted light emitted by the transmitter and emit the emitted light to a target object outside the housing. The reflective part is used to receive the echo light reflected back from the target object outside the housing and emit the echo light to the receiver. At least one of the polarization extinction modules is located on the side of the beam splitter away from the receiver.

[0014] In some embodiments, a window is included, the housing is provided with a window, the window covers the window and is connected to the housing, and at least one of the polarization extinction modules is disposed adjacent to the window.

[0015] In some embodiments, at least one of the polarization extinction modules is positioned adjacent to the transmitter.

[0016] In some embodiments, at least one of the polarization extinction modules is positioned adjacent to the receiver.

[0017] In this embodiment of the lidar, the polarization extinction module is located in the non-primary ray region. Therefore, the polarization extinction module has almost no impact on the optical signal in the primary ray region, but is mainly used to process the optical signal in the non-primary ray region. The optical signal in the non-primary ray region includes stray light. The polarization extinction module can attenuate the intensity of stray light emitted and / or reflected through the module by adjusting the polarization state of the stray light in the non-primary ray region, thereby reducing the impact of stray light on the lidar's detection results and improving the lidar's detection accuracy. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a partial structural schematic diagram of a lidar provided in some embodiments of this application; Figure 2 yes Figure 1 The diagram shown is a structural schematic of the polarization extinction module in a lidar. Figure 3 yes Figure 1 The diagram shown is a structural schematic of the polarization extinction module in a lidar. Figure 4 yes Figure 1 The diagram shown is a structural schematic of the polarization extinction module in a lidar. Figure 5 yes Figure 1 The diagram shown is a structural schematic of the polarization extinction module in a lidar. Figure 6 yes Figure 1 The diagram shown is a structural schematic of the polarization extinction module in a lidar. Figure 7 This is a partial structural schematic diagram of a lidar provided in some embodiments of this application; Figure 8 This is a partial structural schematic diagram of a lidar provided in some embodiments of this application.

[0020] Explanation of reference numerals in the attached figures: 1. LiDAR; 10. Shell; 11. Window; 20. Transmitter; 21. Transmitting lens; 30. Receiver; 31. Receiving lens; 40. Beam splitter; 41. Light-transmitting part; 42. Reflecting part; 50. Polarization extinction module; 50a, First polarization extinction module; 51a, First linear polarizer; 52a, First polarization converter; 521a, First quarter-wave plate; 53a, Reflector; 50b, Second polarization extinction module; 51b, Second linear polarizer; 52b, Second polarization converter; 521b, Second quarter-wave plate; 522b, First half-wave plate; 523b, Third quarter-wave plate; 524b, Second half-wave plate; 53b, Third linear polarizer; 50c, Third polarization extinction module; 51c, Fourth linear polarizer; 52c, Fifth linear polarizer; 60. Window film; 70. Transceiver module; 71. Optical scanner; 72. Transceiver lens. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0022] In the following description, when referring to the accompanying drawings, the same numbers in different drawings denote the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0023] Please see Figure 1 This application provides a lidar 1, which includes a housing 10, a transmitter 20, a receiver 30, and at least one polarization extinction module 50. The transmitter 20 is located inside the housing 10 and is used to emit emitted light. The receiver 30 is located inside the housing 10 and is used to receive echo light. The polarization extinction module 50 is located inside the housing 10 and is located in a non-main ray region. The polarization extinction module 50 is used to regulate the polarization state of the light signal to attenuate the intensity of the light signal emitted and / or reflected through the polarization extinction module 50.

[0024] Since the aforementioned polarization extinction module 50 is located in the non-primary ray region, its placement has almost no impact on the optical signal in the primary ray region, but primarily serves to process the optical signal in the non-primary ray region. The optical signal in the non-primary ray region includes stray light. The polarization extinction module 50 can attenuate the intensity of stray light emitted and / or reflected through it by adjusting the polarization state of the stray light in the non-primary ray region, thereby reducing the impact of stray light on the detection results of the lidar 1 and improving the detection accuracy of the lidar 1.

[0025] It should be noted that stray light includes pre-lead light. Pre-lead light refers to the light signal from the internal components of the lidar reaching the detector before it is emitted from the lidar. The presence of pre-lead light causes the detector to receive strong echo energy from the lidar's internal components for a short period, leading to detector saturation. During the detector's saturation recovery process, the detector cannot function, losing its detection capability within that time range, affecting the reception of echo light corresponding to nearby targets, thus creating a near-field blind zone. The aforementioned polarization extinction module 50 is located in the optical path of the pre-lead light. It can attenuate the intensity of the pre-lead light emitted and / or reflected through the polarization extinction module 50 by controlling the polarization state of the pre-lead light, thereby reducing the impact of the pre-lead light on the detection performance of the lidar 1, improving the detection accuracy of the lidar 1 for nearby targets, and increasing the detection field of view of the lidar 1.

[0026] Since the polarization extinction module 50 can attenuate the intensity of the lead-in light emitted and / or reflected by it, the emission power of the transmitter 20 can be appropriately increased, thereby improving the ranging energy of the lidar 1. Alternatively, the resource consumption of hardware and software can be reduced without increasing costs. Or, different hardware solutions can be adopted to avoid excessive increases in hardware costs and achieve better results.

[0027] The polarization extinction module 50 is used to regulate the polarization state of the optical signal. It can change the polarization state of the optical signal (e.g., the conversion between linearly polarized light and circularly polarized light, the change of the rotation direction of circularly polarized light, etc.) and / or filter polarized light with a certain polarization direction for the polarization extinction module 50.

[0028] In the non-main ray region, the proportion of emitted light in the optical signal is less than a first preset value, and the proportion of echo light is less than a second preset value. The first preset value can be selected according to actual needs; for example, it can be 6%, 8%, 10%, 12%, 14%, etc., without limitation. The second preset value can also be selected according to actual needs; for example, it can be 6%, 8%, 10%, 12%, 14%, etc., without limitation.

[0029] Understandably, when determining the specific installation location of the polarization extinction module 50, it is necessary to first determine the non-master ray region. This non-master ray region can be obtained by fitting the optical path using a simulation system. Specifically, the optical path can be fitted using a simulation system to obtain the energy ratio of emitted and echoed light in each region of the optical path, and the master ray region and non-master ray region can be divided based on this energy ratio. Within the master ray region, the energy ratio of emitted light is greater than or equal to a third pre-value, or the energy ratio of echoed light is greater than or equal to a fourth pre-value. The third pre-value can be selected according to actual needs; for example, it can be 86%, 88%, 90%, 92%, 94%, etc., without limitation. The fourth pre-value can also be selected according to actual needs; for example, it can be 86%, 88%, 90%, 92%, 94%, etc., without limitation.

[0030] See Figure 2 and Figure 3 At least one polarization extinction module 50 includes a first polarization extinction module 50a, which includes a first linear polarizer 51a and a first polarization converter 52a distributed along the transmission direction of the optical signal.

[0031] The first linear polarizer 51a is used to receive optical signals from non-main ray regions and output first linearly polarized light. A linear polarizer can convert multiple polarized lights into a single polarized light.

[0032] The first polarization converter 52a is used to receive first linearly polarized light and adjust its polarization state to output first circularly polarized light. The first polarization converter 52a is also used to receive at least a portion of the reflected light from the surface of the first circularly polarized light and output second linearly polarized light. The polarization direction of the second linearly polarized light intersects that of the first linearly polarized light. Thus, the second linearly polarized light cannot pass through the first linear polarizer 51a, achieving the blocking of stray light reflected by the polarization extinction module 50 and realizing an extinction isolation effect.

[0033] The first polarization converter 52a includes a first quarter-wave plate 521a. The quarter-wave plate can receive linearly polarized light and output circularly polarized light, or receive circularly polarized light and output linearly polarized light. That is, by designing the first polarization converter 52a to include the first quarter-wave plate 521a, the requirement of the first polarization converter 52a receiving first linearly polarized light and outputting first circularly polarized light can be met, resulting in a simple structure and low design cost. When circularly polarized light is reflected by the surface, its propagation direction is reversed, causing the rotation direction to reverse. When the reflected light passes through the quarter-wave plate again, it will output polarized light perpendicular to the original linear polarization direction.

[0034] Specifically, the first quarter-wave plate 521a receives the first linearly polarized light and outputs the first circularly polarized light. The first circularly polarized light is reflected by the surface and outputs the second circularly polarized light. The rotation direction of the second circularly polarized light is opposite to that of the first circularly polarized light. Thus, the second linearly polarized light received by the first quarter-wave plate 521a and output by it will be perpendicular to the polarization direction of the first linearly polarized light, preventing the second linearly polarized light from passing through the first linearly polarized plate 51a.

[0035] See Figure 2 The surface that reflects the first circularly polarized light can be the inner surface of the housing 10, the surface of the internal components of the lidar 1, etc., and is not limited thereto.

[0036] See Figure 3 The surface that reflects the first circularly polarized light is the reflecting surface of the reflector 53a. That is, the first polarization extinction module 50a includes the reflector 53a, which is located on the side of the first polarization converter 52a away from the first linear polarizer 51a along the direction of light signal transmission. Designing the reflector 53a as the surface that reflects the first circularly polarized light, compared to the inner surface of the housing 10 or the surface of the internal components of the lidar 1 as the reflecting surface, makes the surface reflectivity, shape, and placement of the reflector 53a more controllable. This is beneficial for ensuring that the first circularly polarized light is reflected by the reflector 53a toward the first polarization converter 52a (first quarter-wave plate 521a), preventing it from passing through the first linear polarizer 51a, and thus blocking stray light reflected by the polarization extinction module 50a.

[0037] See Figure 4 and Figure 5 At least one polarization extinction module 50 includes a second polarization extinction module 50b, which includes a second linear polarizer 51b, a second polarization converter 52b, and a third linear polarizer 53b distributed along the transmission direction of the optical signal. The polarization direction of the second linear polarizer 51b is parallel to the polarization direction of the third linear polarizer 53b.

[0038] The second linear polarizer 51b is used to receive optical signals from non-main ray regions and output third linearly polarized light. The second polarization converter 52b is used to receive the third linearly polarized light and adjust its polarization state to output fourth linearly polarized light. The polarization directions of the fourth linearly polarized light intersect with those of the third linearly polarized light. Thus, the fourth linearly polarized light cannot pass through the third linear polarizer 53b, effectively blocking stray light emitted via the polarization extinction module 50 and achieving an extinction isolation effect.

[0039] Even if the fourth linearly polarized light is reflected back to the second polarization converter 52b and the third linear polarization converter 53b via the third linear polarizer 53b, and exits on the side of the third linear polarizer 53b away from the second polarization converter 52b, the energy of the exited light signal will gradually weaken after passing through the devices in the second polarization extinction module 50b, and the energy will be greatly reduced compared to the original light signal entering the second linear polarizer 51b.

[0040] That is, the second polarization extinction module 50b can both block stray light emitted through it and attenuate stray light reflected through it, thus achieving a better extinction isolation effect.

[0041] See Figure 4 In some embodiments, the second polarization converter 52b includes a second quarter-wave plate 521b, a first half-wave plate 522b, and a third quarter-wave plate 523b distributed along the transmission direction of the optical signal. The quarter-wave plate is capable of receiving linearly polarized light and outputting circularly polarized light, or receiving circularly polarized light and outputting linearly polarized light. The half-wave plate is capable of receiving circularly polarized light and reversing its rotation direction.

[0042] Specifically, the second quarter-wave plate 521b receives the third linearly polarized light and outputs the third circularly polarized light. The third circularly polarized light passes through the first half-wave plate 522b and outputs the fourth circularly polarized light with reversed rotation. The fourth circularly polarized light passes through the third quarter-wave plate 523b and outputs the fourth linearly polarized light. The polarization direction of the fourth linearly polarized light is perpendicular to the polarization direction of the third linearly polarized light, so that the fourth linearly polarized light cannot pass through the third linearly polarizing plate 53b.

[0043] See Figure 5 In other embodiments, the second polarization converter 52b includes a second half-wave plate 524b. The half-wave plate is capable of receiving linearly polarized light and reversing its rotation.

[0044] Specifically, the second half-wave plate 524b receives the third linearly polarized light and outputs the fourth linearly polarized light. The polarization direction of the fourth linearly polarized light is perpendicular to the polarization direction of the third linearly polarized light, so that the fourth linearly polarized light cannot pass through the third linearly polarizing plate 53b.

[0045] See Figure 6 At least one polarization extinction module 50 includes a third polarization extinction module 50c, which includes a fourth linear polarizer 51c and a fifth linear polarizer 52c distributed along the transmission direction of the optical signal. The polarization direction of the fourth linear polarizer 51c is perpendicular to the polarization direction of the fifth linear polarizer 52c.

[0046] The fourth linear polarizer 51c is used to receive optical signals from non-main ray regions and output fifth linearly polarized light. In this way, the fifth linearly polarized light will not be able to pass through the fifth linear polarizer 52c, thereby blocking stray light emitted through the polarization extinction module 50 and achieving an extinction isolation effect.

[0047] Even if the fifth linearly polarized light is reflected back to the fourth linearly polarized light 51c by the fifth linearly polarized light 52c and exits on the side of the fourth linearly polarized light 51c away from the fifth linearly polarized light 52c, the energy of the exited light signal will gradually weaken after passing through the devices in the third polarization extinction module 50c, and the energy will be greatly reduced compared to the original light signal entering the fourth linearly polarized light 51c.

[0048] In other words, the third polarization extinction module 50c can both block stray light emitted through it and attenuate stray light reflected through it, thus achieving a better extinction isolation effect.

[0049] The reflectivity of the linear polarizers (e.g., the first linear polarizer 51a, the second linear polarizer 51b, the third linear polarizer 53b, the fourth linear polarizer 51c, and the fifth linear polarizer 52c) is less than a first preset value. This reduces the energy of the optical signal reflected by the linear polarizers, further attenuating stray light reflected by the polarization extinction module 50.

[0050] The first preset value can be selected according to actual needs; for example, the first preset value can be 1%, 2%, 3%, 4%, 5%, etc., without limitation.

[0051] It should be noted that if the transmission path of the optical signal to the linear polarizer is short, the reflectivity of the linear polarizer can be designed to be lower; for example, the reflectivity of the first linear polarizer 51a, the second linear polarizer 51b, the fourth linear polarizer 51c, and the fifth linear polarizer 52c can be designed to be lower. Specifically, the reflectivity of the first linear polarizer 51a, the second linear polarizer 51b, the fourth linear polarizer 51c, and the fifth linear polarizer 52c can be less than 1%.

[0052] Linear polarizers (e.g., first linear polarizer 51a, second linear polarizer 51b, third linear polarizer 53b, fourth linear polarizer 51c, and fifth linear polarizer 52c) can be polarizing films (linear polymer film polarizers) made of polyvinyl alcohol (PVA) sheets. During manufacturing, these sheets are stretched and iodine-dyed to allow only light of a single polarization direction to pass through. Simultaneously, light of all other directions is repelled by this polarizer, or absorbed in the case of dichroic polarizers.

[0053] The lidar 1 may include one or more of the first polarization extinction module 50a, the second polarization extinction module 50b, and the third polarization extinction module 50c. It can be designed according to actual needs and is not limited thereto.

[0054] The polarization extinction module 50 can be set at any position within the lidar 1 where extinction is required, without any limitation.

[0055] At least one polarization extinction module 50 is disposed adjacent to the transmitter 20 to attenuate stray light near the transmitter 20. For example, at least one polarization extinction module 50 is located on the side of the transmitting lens 21 closest to the transmitter 20. Alternatively, at least one polarization extinction module 50 is located on the side of the transmitting lens 21 furthest from the transmitter 20. Furthermore, when there are multiple transmitting lenses 21, a polarization extinction module 50 is disposed between adjacent transmitting lenses 21.

[0056] At least one polarization extinction module 50 is disposed adjacent to the receiver 30 to attenuate stray light near the transmitter 20. For example, at least one polarization extinction module 50 is located on the side of the receiving lens 31 closer to the receiver 30. Alternatively, at least one polarization extinction module 50 is located on the side of the receiving lens 31 furthest from the receiver 30. Furthermore, when there are multiple receiving lenses 31, a polarization extinction module 50 is disposed between adjacent receiving lenses 31.

[0057] The source light emitted from transmitter 20 can be composed of various linearly polarized lights. The stray light formed within lidar 1 is composed of various linearly polarized lights. The first linear polarizer 51a in the first polarization extinction module 50a allows the stray light with the corresponding polarization direction to pass through and attenuates it; the second linear polarizer 51b in the second polarization extinction module 50b allows the stray light with the corresponding polarization direction to pass through and attenuates it; the fourth linear polarizer 51c in the third polarization extinction module 50c allows the stray light with the corresponding polarization direction to pass through and attenuates it.

[0058] The source light emitted from transmitter 20 can consist of a single polarized light, defined as initial linearly polarized light. The polarization direction of the initial linearly polarized light is parallel to the polarization directions of the first linear polarizer 51a in the first polarization extinction module 50a, the second linear polarizer 51b in the second polarization extinction module 50b, and the fourth linear polarizer 51c in the third polarization extinction module 50c. Thus, the polarization direction of the stray light generated within lidar 1 is approximately parallel to the polarization directions of the first linear polarizer 51a in the first polarization extinction module 50a, the second linear polarizer 51b in the second polarization extinction module 50b, and the fourth linear polarizer 51c in the third polarization extinction module 50c. This allows more stray light to enter the first polarization extinction module 50a, the second polarization extinction module 50b, and the third polarization extinction module 50c, where its energy is attenuated. In this case, the second linear polarizer 51b in the second polarization extinction module 50b can be removed or retained according to the corresponding situation through simulation or experiment. If the second linear polarizer 51b in the second polarization extinction module 50b is removed, the second polarization converter 52b in the second polarization extinction module 50b is used to receive optical signals from non-main ray regions.

[0059] Emitter 20 may include a VCSEL (Vertical-Cavity Surface-Emitting Laser). The VCSEL itself outputs linearly polarized light, the polarization direction of which is typically determined by the anisotropy of the crystal structure within the laser, generally divided into two orthogonal linear polarization modes along the lattice direction. However, in free operation, its polarization direction may randomly switch due to temperature, current fluctuations, or external disturbances (polarization reversal), leading to unstable output polarization. Of course, stable polarization direction locking can also be achieved through special designs (such as surface gratings, cavity structure optimization, or external feedback control).

[0060] The lidar 1 in this application embodiment can be a coaxial architecture or an off-axis architecture, and there is no limitation on this.

[0061] If LiDAR 1 is a coaxial architecture, refer to... Figure 1 The lidar 1 includes a beam splitter 40 located inside the housing 10. The beam splitter 40 includes a light-transmitting part 41 and a reflective part 42 connected to the light-transmitting part 41. One of the light-transmitting part 41 and the reflective part 42 is used to receive the emitted light emitted by the transmitter 20 and emit the emitted light to a target object outside the housing 10. The other of the light-transmitting part 41 and the reflective part 42 is used to receive the echo light reflected back from the target object outside the housing 10 and emit the echo light to the receiver 30.

[0062] One of the aforementioned light-transmitting part 41 and reflective part 42 is used to receive the emitted light emitted by the transmitter 20, and the other is used to receive the echo light reflected back by the target object outside the housing 10. Alternatively, the light-transmitting part 41 can receive the emitted light emitted by the transmitter 20, while the reflective part 42 can receive the echo light reflected back by the target object outside the housing 10.

[0063] In this embodiment, the light-transmitting part 41 receives the emitted light emitted by the transmitter 20, while the reflective part 42 is used to receive the echo light reflected back by the target object outside the housing 10, and the reflective part 42 is located on the periphery of the light-transmitting part 41.

[0064] In actual manufacturing, light-transmitting devices (e.g., light-transmitting section 41) rarely achieve 100% transmittance and always have a certain reflectivity. This causes the emitted light to travel through the housing 10 before reaching the receiver 30, resulting in a pre-lead light. Specifically, the pre-lead light is generated because some of the emitted light from the transmitter 20 is reflected by the light-transmitting section 41 instead of passing through it, and then reflected back to the light-transmitting section 41 by a device (e.g., housing 10) along the reflection path, before being transmitted through the light-transmitting section 41 towards the receiver 30. In other words, at least a portion of the pre-lead light is emitted to the receiver 30 through the light-transmitting section 41. Based on this, this embodiment of the application designs at least one polarization extinction module 50 located on the side of the beam splitter 40 furthest from the receiver 30. In this way, the polarization extinction module 50 can attenuate the leading light before it is emitted by the beam splitter 40 toward the receiver 30, thereby improving the detection accuracy of the lidar 1 for near-range targets and increasing the detection field of view of the lidar 1.

[0065] A first polarization extinction module 50a is provided on the side of the beam splitter 40 away from the receiver 30. The first polarization extinction module 50a enables some of the polarized light in the stray light to pass through and be converted into circularly polarized light. After being reflected by the reflector 53a or the housing 10, the polarization state is changed and no energy is reflected back to be received by the receiver 30, thereby eliminating the leading light in this area.

[0066] The lidar 1 includes a window 60, and a housing 10 is provided with a window 11. The window 60 blocks the window 11 and is connected to the housing 10. The window 60 is used to receive the emitted light output by the beam splitter 40 and emit the emitted light to a target object outside the housing 10; the window 60 is also used to receive the echo light reflected back from the target object outside the housing 10 and emit the echo light to the beam splitter 40.

[0067] Since the window 60 cannot achieve 100% transmittance and will always have a certain reflectivity, the emitted light may not exit the housing 10 but instead be reflected by the window 60, reach the beam splitter 40, and then be transmitted to the receiver 30, generating a leading light. Based on this, this embodiment of the application designs at least one polarization extinction module 50 adjacent to the window 60. In this case, the polarization extinction module 50 can attenuate this portion of the leading light before it is emitted by the beam splitter 40 towards the receiver 30, improving the detection accuracy of the lidar 1 for near-range targets and increasing the detection field of view of the lidar 1.

[0068] See Figure 7 and Figure 8 The lidar 1 includes a transceiver module 70 located within a housing 10. The transceiver module 70 receives emitted light from a beam splitter 40 and transmits the emitted light to a target object outside the housing 10. The transceiver module 70 also receives echo light reflected back from the target object outside the housing 10 and transmits the echo light to the beam splitter 40. The transceiver module 70 may include an optical scanner 71 and / or a transceiver lens 72. The optical scanner 71 is rotatable to change the output direction of the emitted light and can receive echo light from multiple directions, which helps increase the emission and reception field of view of the lidar 1. The optical scanner 71 can be one or more of a rotating mirror, a galvanometer, or a prism, and is not limited thereto. The transceiver lens 72 can be used to collimate the emitted light and also to converge the echo light, facilitating the transmission of large-angle echo light to the beam splitter 40. The transceiver module 70 may include one transceiver lens 72 or multiple transceiver lenses 72, and there is no limitation on this.

[0069] The transceiver module 70 (e.g., optical scanner 71, transceiver lens 72) cannot achieve 100% transmittance and will always have a certain reflectivity. This causes the emitted light to be reflected by the transceiver module 70 inside the housing 10 before exiting the housing 10, reaching the beam splitter 40, and further transmitted to the receiver 30, generating a lead-in light. Based on this, this embodiment of the application designs at least one polarization extinction module 50 adjacent to the transceiver module 70. Thus, the polarization extinction module 50 can attenuate this portion of the lead-in light before it is emitted by the beam splitter 40 towards the receiver 30, improving the detection accuracy of the lidar 1 for near-range targets and increasing the detection field of view of the lidar 1.

[0070] In the description of this application, it should be understood that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances. Furthermore, in the description of this application, unless otherwise stated, "multiple" means at least two, for example, two, three, four, etc. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship.

[0071] The above-disclosed embodiments are merely preferred embodiments of this application and should not be construed as limiting the scope of this application. Therefore, any equivalent variations made in accordance with the claims of this application shall still fall within the scope of this application.

Claims

1. A lidar, characterized in that, include: case; The transmitter, located inside the housing, is used to emit light. A receiver, located inside the housing, is used to receive echo light; At least one polarization extinction module is located inside the housing. The polarization extinction module is located in the non-main ray region. The polarization extinction module is used to regulate the polarization state of the light signal to attenuate the intensity of the light signal emitted and / or reflected through the polarization extinction module.

2. The lidar according to claim 1, characterized in that, The at least one polarization extinction module includes: The first polarization extinction module includes a first linear polarizer and a first quarter-wave plate distributed along the transmission direction of the optical signal.

3. The lidar according to claim 2, characterized in that, The first polarization extinction module includes: The reflector is located on the side of the first quarter-wave plate away from the first linear polarizer, along the direction of light signal transmission.

4. The lidar according to claim 1, characterized in that, The at least one polarization extinction module includes: The second polarization extinction module includes a second linear polarizer, a second polarization converter, and a third linear polarizer distributed along the transmission direction of the optical signal. The polarization direction of the third linear polarizer is parallel to the polarization direction entering the second linear polarizer. The second polarization converter is used to change the polarization state of the linearly polarized light output by the second linear polarizer.

5. The lidar according to claim 4, characterized in that, The second polarization converter includes a second quarter-wave plate, a first half-wave plate, and a third quarter-wave plate distributed along the transmission direction of the optical signal.

6. The lidar according to claim 4, characterized in that, The second polarization converter includes a second half-wave plate.

7. The lidar according to claim 1, characterized in that, The at least one polarization extinction module includes: The third polarization extinction module includes a fourth linear polarizer and a fifth linear polarizer distributed along the transmission direction of the optical signal. The polarization direction of the fourth linear polarizer is perpendicular to the polarization direction of the fifth linear polarizer, and the reflectivity of the fifth linear polarizer is less than or equal to 5%.

8. The lidar according to claim 1, characterized in that, The transmitter emits initial linearly polarized light, the polarization direction of which is parallel to the polarization directions of the first, second, and fourth linearly polarized plates.

9. The lidar according to claim 1, characterized in that, include: The beam splitter, located inside the housing, includes a light-transmitting part and a reflective part connected to the light-transmitting part. The light-transmitting part is used to receive the emitted light emitted by the transmitter and emit the emitted light to a target object outside the housing. The reflective part is used to receive the echo light reflected back from the target object outside the housing and emit the echo light to the receiver. At least one of the polarization extinction modules is located on the side of the beam splitter away from the receiver.

10. The lidar according to claim 1, characterized in that, The housing includes a window, the housing is provided with a window, the window covers the window and is connected to the housing, and at least one of the polarization extinction modules is disposed adjacent to the window; And / or, at least one of the polarization extinction modules is disposed adjacent to the emitter; And / or, at least one of the polarization extinction modules is positioned adjacent to the receiver.

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