Optical system, detection apparatus, and terminal

Abstract

An optical system (100), a detection apparatus, and a terminal. The optical system (100) comprises a scanning module (101), a first prism module (102) and a receiver (103), wherein the first prism module (102) comprises one or more first prisms (1021, 1022, 1023), and the first prism module (102) comprises a first incident surface and a first emergent surface; the scanning module (101) is used for reflecting a first light beam, the first light beam comprising a light beam reflected or scattered by an object; the first prism module (102) is used for adjusting the propagation direction of the reflected first light beam, the reflected first light beam being incident from the first incident surface at a first incident angle and being emitted from the first emergent surface, and the refractive index of the first light beam in the one or more first prisms (1021, 1022, 1023) being related to the first incident angle; and the receiver (103) is used for receiving the first light beam emitted from the first prism module (102). Therefore, the compensation for an offset angle in the propagation direction of an echo light beam can be realized, thereby optimizing the detection precision.

Description

Optical systems, detection devices and terminals

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of China on February 5, 2024, with application number 202410173123.9, and priority to the Chinese patent application entitled “Optical system, detection device and terminal”, all contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of detection technology, and in particular to an optical system, a detection device and a terminal. Background Art

[0003] In most current LiDAR detection scenarios, a scanning module (such as a scanning mirror) is often required to assist in scanning and complete detection. The scanning module not only needs to scan the outgoing light beam, but also needs to reflect the echo beam formed by reflection or scattering from the object. Due to the continuous movement of the scanning module, after the light beam is reflected by the object, the angle at which the scanning module receives the echo beam is already different from the angle at which the scanning beam is emitted. This will cause the angle of the propagation direction of the echo beam after passing through the scanning module to shift. This angle shift increases as the detection distance increases. For typical single-mode optical fiber or waveguide systems, this angle shift will cause the light spot on the focal plane of the lens to shift. This will reduce the light energy coupled into the optical fiber or waveguide, thereby affecting the detection accuracy of the LiDAR. Summary of the Invention

[0004] The present application provides an optical system, a detection device and a terminal, which can compensate for the offset angle of the propagation direction of the echo light beam and optimize the detection accuracy.

[0005] In a first aspect, the present application provides an optical system, comprising a scanning module, a first prism module, and a receiver, wherein the first prism module comprises one or more first prisms, and the first prism module comprises a first incident surface and a first exit surface;

[0006] The scanning module is used to reflect a first light beam, wherein the first light beam includes a light beam reflected or scattered by an object;

[0007] The first prism module is used to adjust the propagation direction of the reflected first light beam; the reflected first light beam is incident from the first incident surface at a first incident angle and is emitted from the first exit surface; the refractive index of the first light beam in the one or more first prisms is related to the first incident angle;

[0008] The receiver is used to receive the first light beam emitted from the first prism module.

[0009] Exemplarily, the first prism may be an anisotropic crystal prism. Exemplarily, the receiver includes a receiving optical fiber and a detector.

[0010] In the above scheme, the propagation direction of the echo light beam (such as the above-mentioned first light beam) is adjusted by the above-mentioned first prism module. Specifically, since the refractive index of the first prism in the first prism module can be adjusted by changing the incident angle of the light beam, a reasonable selection of the incident angle of the light beam can make the light beam emitted from the first prism module meet the requirements of propagation direction angle compensation. Thereby, the propagation direction angle deviation caused by the scanning module is compensated, and the light energy of the echo light beam received by the receiver can be increased, so as to obtain more information and improve the detection accuracy. Furthermore, compensating for the propagation direction angle deviation caused by the scanning module by the first prism has the characteristics of easy implementation and low cost, and the angle deviation can be reduced by several times.

[0011] In addition, in the above-mentioned optical system, the first prism module may include one or more first prisms. In a specific implementation, since the angle compensation of a first prism is limited, if the angle offset compensation caused by the scanning module can be achieved by using a first prism, then the first prism module may include a first prism. If the angle offset caused by the scanning module is large and the use of a first prism can no longer meet the compensation requirements, then multiple first prisms can be used. It can be seen that this solution can flexibly select the number of first prisms to meet different compensation requirements, and has a wide range of application scenarios.

[0012] In a possible embodiment, the polarization direction of the first light beam is non-perpendicular to the optical axis of the first prism. Exemplarily, the refraction caused by the reflected first light beam upon entering the first incident surface is extraordinary light refraction.

[0013] In the above solution, the first light beam incident on the first prism can produce refraction in accordance with the extraordinary light refraction law, so as to realize reasonable selection of refractive index to change the propagation direction of the first light beam and realize compensation for the propagation direction angle offset.

[0014] In a possible implementation, when the scanning module is configured to reflect the first light beam at different scanning angles, the receiver receives the first light beam emitted from the first prism module.

[0015] In the above solution, due to the different distances between the object and the scanning module, the time required for the light beam to be reflected or scattered back to the scanning module by the object varies, and thus the angle at which the scanning module moves during this process also varies. Therefore, the scanning angle of the light beam reflected by the scanning module also varies. The angular offset of the light beam after reflection from the scanning module also varies. In contrast, in the present application solution, the receiver can better receive the light beam reflected back by the scanning module at different scanning angles. That is, the first prism module can compensate for the angular offset caused by the different scanning angles of the scanning module.

[0016] In a possible implementation, if the first prism module includes a first prism, the first incident surface and the first exit surface are flat or curved surfaces of the first prism;

[0017] If the first prism module includes multiple first prisms, the first incident surface belongs to the plane or curved surface of one of the multiple first prisms, the first exit surface belongs to the plane or curved surface of another first prism, and the first light beam passes through the multiple first prisms.

[0018] In a possible embodiment, the optical system further includes a second prism module, the second prism module is used to expand the aperture of the first light beam; the second prism module includes one or more second prisms;

[0019] The aforementioned second prism module includes a second incident surface and a second exit surface; the aforementioned first light beam reflected by the aforementioned scanning module is incident from the aforementioned second incident surface, and after being emitted from the aforementioned second exit surface, it is incident on the aforementioned first prism module from the aforementioned first incident surface at the aforementioned first incident angle; the aperture of the aforementioned first light beam emitted from the aforementioned second exit surface is larger than the aperture of the aforementioned first light beam incident from the aforementioned second incident surface.

[0020] In the above scheme, since the beam aperture will be reduced after passing through the first prism, the aperture can be expanded through the second prism module, and then the beam with the expanded aperture is incident on the first prism module again, thereby achieving beam aperture compensation and further improving the echo beam light energy received by the receiver.

[0021] In one possible embodiment, the refractive index of the aforementioned first light beam in the aforementioned one or more second prisms is the same as the refractive index of the aforementioned first light beam in the aforementioned one or more first prisms; or, the deviation between the refractive index of the aforementioned first light beam in the aforementioned one or more second prisms and the refractive index of the aforementioned first light beam in the aforementioned one or more first prisms is less than a preset threshold.

[0022] Exemplarily, the second prism is an isotropic glass prism or a transparent plastic prism.

[0023] In the above solution, the refractive index of the second prism module and the first prism is the same or the deviation is small, which can optimize the aperture compensation effect.

[0024] In one possible embodiment, the optical system further includes a polarization adjuster configured to adjust the polarization direction of the first light beam to a first polarization direction; the first light beam incident on the first incident surface is a light beam polarized by the polarization adjuster. Exemplarily, the polarization adjuster is a quarter-wave plate or a half-wave plate.

[0025] In the above solution, the polarization adjuster can change the polarization direction of the light beam so that the polarization direction of the light beam incident on the first prism module is not perpendicular to the optical axis of the first prism, thereby meeting the system design requirement of generating extraordinary light refraction after the light beam enters the first prism module.

[0026] In a possible implementation, the optical system further includes a beam aperture adjuster, and the beam aperture adjuster is used to reduce the aperture of the first light beam;

[0027] The first light beam incident on the first prism module is a light beam whose aperture is reduced by the beam aperture adjuster.

[0028] Exemplarily, the aforementioned beam aperture adjuster includes a Kepler beam expansion / contraction system or a Galilean beam expansion / contraction system.

[0029] In the above solution, the beam aperture adjuster can change the aperture of the beam to meet the design requirements of the system.

[0030] In a possible implementation, the optical system further includes a polarization beam splitter, and the polarization beam splitter is configured to reflect the first light beam in the first polarization direction to the receiver.

[0031] In the above solution, the polarization beam splitter can be used to select the required polarized light to meet the design requirements of the system.

[0032] In a possible implementation, the optical system further includes a reflector, and the reflector is configured to reflect the first light beam reflected from the scanning module so that the first light beam propagates in the direction of the first prism module.

[0033] In the above solution, the propagation direction of the light beam can be changed by the reflector to meet the design requirements of the receiving light path.

[0034] In a possible implementation manner, the first light beam is emitted from the first exit surface at a first exit angle;

[0035] The optical system further includes an emitter for emitting a second light beam; the first exit surface is an incident surface for the second light beam, and the first incident surface is an exit surface for the second light beam;

[0036] The first prism module is further used to adjust the propagation direction of the second light beam; the second light beam is incident from the first exit surface at a second incident angle and is emitted from the first incident surface;

[0037] The second incident angle is the same as the first exit angle, or an angular deviation between the second incident angle and the first exit angle is less than an angle threshold.

[0038] In the above solution, the optical system is a system with a common transmission and reception path, which can save components and reduce costs. In addition, the second incident angle is the same as the first exit angle or has a small deviation, which can reduce light energy loss and improve the overall efficiency of the system.

[0039] In a possible implementation, the polarization direction of the second light beam is perpendicular to the polarization direction of the first light beam.

[0040] In the above solution, the polarization directions of the emitted light beam (second light beam) and the echo light beam (first light beam) are perpendicular, which can optimize the overall efficiency of the system.

[0041] In a possible implementation manner, the first light beam is emitted from the first emission surface at an emission angle of 90°.

[0042] In the above solution, the first light beam is emitted vertically from the first prism module, which can reduce the polarization change of the emitted light beam and optimize the overall efficiency.

[0043] In a second aspect, the present application provides a detection device, which includes an optical system as described in any one of the first aspects above.

[0044] In a third aspect, the present application provides a terminal, which includes the optical system as described in any one of the first aspects above; or, includes the detection device as described in the second aspect above. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 is a schematic diagram of birefringence;

[0046] FIG2 is a schematic diagram showing the refraction of extraordinary light in a crystal prism;

[0047] Figures 3 and 4 are schematic diagrams of the wavefront of the light beam;

[0048] FIG5 is a schematic diagram showing the change of the refractive index of extraordinary light with the angle θ;

[0049] FIG6 is a schematic diagram showing the refraction of light in an isotropic prism;

[0050] FIG7 shows a schematic diagram of the detection device system architecture;

[0051] FIG8 is a schematic diagram of the return beam deviation;

[0052] 9 , 9A, and 10 to 16 are schematic diagrams of the optical system structure provided in embodiments of the present application. DETAILED DESCRIPTION

[0053] In the embodiment of the present application, "multiple" refers to two or more. In the embodiment of the present application, "and / or" is used to describe the association relationship of associated objects, indicating three relationships that can exist independently. For example, A and / or B can be expressed as follows: A exists alone, B exists alone, or A and B exist at the same time. The description methods such as "at least one of a1, a2, ... and an" used in the embodiment of the present application include the situation where any one of a1, a2, ... and an exists alone, and also include any combination of any multiple of a1, a2, ... and an, each of which can exist alone; for example, the description method of "at least one of a, b and c" includes the situation where a is alone, b is alone, c is alone, a and b combination, a and c combination, b and c combination, or abc combination.

[0054] In this application, the terms "first," "second," and the like are used to distinguish between identical or similar items having substantially the same function or effect. It should be understood that "first," "second," and "nth" do not have a logical or temporal dependency, nor do they limit the quantity or order of execution. It should also be understood that although the following description uses the terms "first," "second," and the like to describe various elements, these elements should not be limited by these terms. These terms are simply used to distinguish one element from another.

[0055] In the various embodiments of the present application, unless otherwise specified or there is a logical conflict, the terms and / or descriptions between the various embodiments are consistent and can be referenced by each other. The technical features in different embodiments can be combined to form new embodiments according to their inherent logical relationships.

[0056] To facilitate understanding, some of the terms and the optical principles involved in the embodiments of the present application are first explained below by way of example.

[0057] 1. Detection device

[0058] The detection device mentioned in this application can be a laser radar or other optical detection device, such as a fusion detection device. Its working principle is to detect the corresponding target object by emitting a light signal and receiving a light signal from the target object.

[0059] The detection device in the embodiments of the present application can be applied to various fields such as intelligent transportation, autonomous driving, atmospheric environment monitoring, geographic surveying and mapping, and drones, and can perform one or more functions of target detection, distance measurement, speed measurement, target tracking, and image recognition. Functions such as distance measurement, speed measurement, target tracking, and image recognition are all implemented on the basis of target detection, so the subsequent description mainly uses detection as an example.

[0060] The detection device in the embodiments of the present application can be applied to a roadside detection device (e.g., an intersection fusion detection device), an on-board detection device (e.g., an on-board fusion detection device), etc., but can also be applied to other detection devices, such as detection devices installed on drones, robots, rail cars, bicycles, traffic lights, speed measuring devices, base stations, etc. This application does not limit the location where the detection device is installed.

[0061] 2. Polarization.

[0062] Polarized light refers to light whose electric vector vibrates in a regular pattern. Polarization is an inherent property of light, and its polarization state is a parameter of light. Polarization states can be categorized as linear polarization and elliptical polarization (or circular polarization in special cases). For linearly polarized light, the polarization state also includes the angle and amplitude; for circularly polarized light, the polarization state also includes the direction of polarization (clockwise or counterclockwise). For example, linearly polarized light has its electric vector vibrating back and forth in a single direction. In contrast, unpolarized light, such as natural light, has its electric vector vibrating in a chaotic manner, neither oriented in a uniform direction nor maintaining a fixed temporal relationship (no fixed phase). Therefore, its vibration is random and has no fixed pattern. To describe the relationship between vibration directions, we typically distinguish between P-polarized light and S-polarized light for basic linearly polarized light (which can be combined to form elliptical polarization). P-polarized light refers to linearly polarized light with a vibration direction parallel to the plane of incidence, while S-polarized light refers to linearly polarized light with a vibration direction perpendicular to the plane of incidence.

[0063] 3. Isotropy and anisotropy.

[0064] Isotropy means that the physical properties of a substance are the same in different directions.

[0065] Anisotropy refers to the fact that the physical properties of a substance are different in different directions.

[0066] For example, the isotropic medium mentioned in the embodiments of the present application may refer to the medium having the same optical properties in different directions. Similarly, the anisotropic medium mentioned in the embodiments of the present application may refer to the medium having different optical properties in different directions.

[0067] 4. Birefringence.

[0068] A beam of light incident on an anisotropic medium refracts into two beams, a phenomenon known as birefringence. See Figure 1 for an example. Both beams are linearly polarized. One beam obeys the laws of refraction and is called the ordinary light or o-ray, lying within the plane of incidence (the plane formed by the incident light and the normal at the point of incidence). The other beam, called the extraordinary light or e-ray, does not obey the laws of refraction and is not necessarily within the plane of incidence.

[0069] For example, the anisotropic medium may be a transparent medium such as anisotropic crystal, glass, or transparent plastic, and the embodiment of the present application does not impose any limitation on this.

[0070] 5. Refraction of e-light.

[0071] The refractive index of e-light is related to factors such as the optical axis, angle of incidence, and dielectric material. For ease of understanding, this application uses a uniaxial crystal as an example. For example, see Figure 2, which illustrates the case of light entering a uniaxial crystal wedge prism from air and then exiting the wedge prism. The wedge prism includes plane 1, plane 2, and plane 3.

[0072] In Figure 2, the plane with x=0 is the interface between the two media. The interface with z=0 is the incident plane formed by the incident light and the normal 1. The y-axis is at the intersection of the interface and the incident plane and is also on plane 1. In addition, the optical axis of the uniaxial crystal wedge prism is shown in Figure 2, where the angle between the optical axis and the z-axis is ψ (0≤ψ≤π), and the angle between the projection of the optical axis on the incident plane and the y-axis is For example, when o-light propagates in a crystal, its polarization direction is perpendicular to the optical axis, so the vibration frequency and speed along all directions are the same. Therefore, the refractive index of o-light in the crystal is the same, and the wavefront formed is a spherical surface, as shown in Figure 3 for example. When e-light propagates in different directions in a crystal, its polarization direction relative to the optical axis is different, and its vibration frequency and speed along all directions are different. Therefore, the refractive index of e-light in the crystal changes with the propagation direction, and the wavefront formed is an ellipsoidal surface, as shown in Figure 4 for example. Based on this, as long as the polarization direction of light is not perpendicular to the optical axis of the crystal, the refractive index of light in the crystal can be changed by changing the direction of light entering the crystal, and then the direction of light exiting the crystal can be adaptively changed, thereby achieving adjustment of the light propagation direction. Based on this conclusion, the relationship between the incident angle and the exit angle of e-light passing through the crystal is quantitatively analyzed below.

[0073] In Figure 2, the angle between the incident light and the normal line 1 is the incident angle, denoted by i. Normal line 1 is perpendicular to plane 1. The e-light refracted after the incident light enters the uniaxial crystal wedge prism from air is denoted by k1. The angle between the refracted light k1 and the normal line 1 is the refraction angle, denoted by β. The angle between the refracted light k1 and the optical axis is denoted by θ. Assuming that the refractive index of air is denoted by n1 and the refractive index of the e-light in the uniaxial crystal wedge prism is denoted by n2, the following calculation formula (1) is obtained: n1*sin(i)=n2(θ)*sin(β).

[0074] From the above formula 1, we can see that the refractive index n2 is a function of the angle θ between the refracted light k1 and the optical axis. For details, please refer to the following formula (2):

[0075] In the above calculation formula (2), n o It represents the refractive index of light with polarization direction perpendicular to the optical axis. Since the polarization direction of o light is perpendicular to the optical axis, n o It is also the refractive index of o light in a uniaxial crystal wedge prism. e It represents the refractive index of light whose polarization direction is parallel to the optical axis. o Less than n e .

[0076] Based on the above calculation formula (2), it can be analyzed that the refractive index n2 changes with the angle θ. The specific change relationship can be shown in Figure 5. It can be seen that the value of n2 is o and n e Furthermore, since θ is the angle between the refracted light k1 and the optical axis, and the propagation direction of the refracted light k1 is related to the incident angle i, changes in the incident angle i affect changes in the included angle θ, and changes in the included angle θ affect changes in the refractive index n2. Conversely, it can be said that the refractive index n2 is related to the incident angle i.

[0077] In addition, in FIG2 , the refracted light k1 will also be refracted when it passes through the uniaxial crystal wedge prism and enters the air. The refracted light is emitted from the uniaxial crystal wedge prism and is referred to as the output light. The polarization direction of the output light is the same as the polarization direction of the refracted light k1. The angle between the refracted light k1 and the normal 2 is the incident angle from the uniaxial crystal wedge prism to the air, represented by α. The normal 2 is perpendicular to the plane 2 of the uniaxial crystal wedge prism. The angle between the output light and the normal 2 is the refraction angle, represented by γ. Then the following calculation formula (3) is obtained: n1*sin(γ)=n2(θ)*sin(α).

[0078] Assume that the angle between plane 1 and plane 2 is s1, which is also called the wedge angle of the uniaxial crystal wedge prism. Calculation shows that α = β - s1. This gives the following equation (4): n1*sin(γ) = n2(θ)*sin(β - s1).

[0079] Based on the above calculation formula (4), we can get formula (5): γ=arcsin[(n2(θ) / n1)*sin(β-s1)]. Since the refractive index n1 of air is approximately equal to 1, we can get γ=arcsin[(n2(θ)*sin(β-s1)]. It can be seen that the output angle γ is related to the included angle θ, the included angle s1 and the refraction angle β. According to calculation formulas (1) and (2), the refraction angle β is related to the incident angle i and the included angle θ. Therefore, the output angle γ is related to the included angle θ, the included angle s1 and the incident angle i. The included angle θ is related to the refractive index n2, and the refractive index n2 is related to the incident angle i. It can be said that the output angle γ is related to the included angle s1 and the incident angle i. Based on this, if it is assumed that the included angle s1 remains unchanged, the output angle γ can be adjusted by adjusting the incident angle i.

[0080] It is understandable that the above-mentioned Figures 2 to 5 mainly take the uniaxial crystal as an example, and do not constitute a limitation to the embodiments of the present application.

[0081] 6. Refraction of light by an isotropic wedge prism.

[0082] For example, the isotropic wedge prism may include an isotropic glass wedge prism or a transparent plastic wedge prism, and the present application is not limited thereto. Light passing through the isotropic wedge prism will be refracted twice. For ease of understanding, please refer to Figure 6 for example. Figure 6 shows a schematic diagram of light entering the isotropic wedge prism from air and then exiting the isotropic wedge prism.

[0083] As can be seen in Figure 6, the isotropic wedge prism includes plane 1, plane 2 and plane 3. The angle between plane 1 and plane 2 is s2. The angle s2 is also called the wedge angle of the isotropic wedge prism. The incident light enters the wedge prism from plane 1 and exits the wedge prism from plane 2. Among them, the incident angle of the incident light entering from plane 1 (that is, the angle between the incident light and the normal 1, the normal 1 is perpendicular to plane 1) is φ1. The refracted light generated is represented by k2, and the corresponding refraction angle (the angle between the refracted light k2 and the normal 1) is φ2. The refracted light k2 is also refracted when it is emitted from plane 2. The incident angle of this refraction is (that is, the angle between the refracted light k2 and the normal 2, the normal 2 is perpendicular to plane 2) φ3. The refracted light generated is simply referred to as the output light, and the corresponding refraction angle (the angle between the output light and the normal 2) is φ4.

[0084] In FIG6 , assuming that the refractive index of air is n1 and the refractive index of the isotropic wedge prism is n2, the following calculation formula (5) is obtained: n1*sinφ1=n2*sinφ2,n2*sinφ3=n1*sinφ4.

[0085] In Figure 6, since normal 1 is perpendicular to plane 1 and normal 2 is perpendicular to plane 2, according to the principle that the sum of the angles in a triangle is π and the sum of the angles in a quadrilateral is 2π, we can obtain: φ2+φ3+π-s2=π, and φ3=s2-φ2. Based on this, combined with calculation formula (5), we can obtain:

[0086] It can be seen that the exit angle φ4 is related to the incident angle φ1, the included angle s2, the refractive index n1 and the refractive index n2.

[0087] It should be understood that the above FIG6 is merely an example and does not constitute a limitation to the embodiments of the present application.

[0088] It is understandable that the surface of the prism described in the embodiment of the present application (such as the crystal wedge prism and the isotropic wedge prism) can be a flat surface or a curved surface. The embodiment of the present application is mainly described by taking a flat surface as an example.

[0089] To facilitate understanding, the following is an exemplary analysis of the defects of current detection devices.

[0090] In a specific implementation, a detection device (such as a laser radar, etc.) can use a scanning module (such as a scanning mirror or a rotating mirror, etc.) to assist in scanning and complete detection. The echo light beam reflected or scattered by the object is generally also reflected by the scanning module and received by the detector. However, due to the continuous movement of the scanning module, the angle of the propagation direction of the echo light beam after passing through the scanning module will be offset. As a result, the light energy coupled into the optical fiber or waveguide will decrease, and the light energy received by the detector will also decrease, thereby affecting the detection accuracy of the laser radar. For ease of understanding, the following is an example of the detection device system architecture shown in Figure 7 and the echo beam offset schematic diagram in Figure 8.

[0091] For example, the working principle of the detection device is first briefly introduced in conjunction with the detection device system shown in Figure 7. Specifically, the transmitter can emit a light beam. The light beam is proportionally divided into two parts by a beam splitter (referred to as the first partial light beam and the second partial light beam, respectively). The first partial light beam is sent to the coupler. Optionally, the polarization direction of the first partial light beam can be adjusted by a polarization plate before being sent to the coupler. The second partial light beam is sent to the circulator. The circulator includes three ports: port ①, port ② and port ③. The second partial light beam enters the circulator from port ① and is output from port ② of the circulator. Then, after being expanded by a lens, the light beam is scanned onto the object to be detected by a scanning module. The echo light beam reflected or scattered by the object returns to the scanning module. After being reflected by the scanning module, the echo light beam is reduced by a lens and enters the circulator from port 2 of the circulator. Then, it is output from port ③ of the circulator to the coupler. The coupler couples the echo light beam and the aforementioned first partial light beam and outputs them to the detector for reception. The detector can be, for example, a photodetector that can convert the received light signal into an electrical signal. After the electrical signal is obtained, it is input into the signal processor for processing to achieve one or more functions of target detection, distance measurement, speed measurement, target tracking or imaging recognition.

[0092] As can be seen from the above description, the echo beam must be reflected by the scanning module before returning to the receiving side. The position of circulator port 2 remains fixed, while the scanning module moves between scanning the beam and reflecting it back to the echo beam. This causes the angular propagation direction of the echo beam to shift after passing through the scanning module. For example, see Figure 8 . In Figure 8 , the scanning module is illustrated using a reflector within the scanning module as an example. ① represents the actual position of the reflector when reflecting the echo beam from an object, and ② represents the position of the reflector when reflecting the beam toward the object. It can be seen that during the time between reflecting the beam from the object and then reflecting the echo beam, the position of the reflector rotates from ② to ①. This rotation of the reflector causes the angular propagation direction of the reflected echo beam to shift. In Figure 8 , the dashed line represents the ideal echo beam reflected by the reflector, assuming the reflector remains stationary. That is, the dashed line represents the echo beam reflected when the reflector is in position ②. The beam represented by the solid line is the offset echo beam reflected by the reflective mirror at position ①.

[0093] In addition, it can be seen in Figure 8 that the offset generated will be different depending on the distance between the object and the scanning module. Specifically, the farther the distance, the greater the offset. For example, referring to (a) and (b) in Figure 8, the distance between the object and the scanning module in Figure 8 (a) is represented as d1, and the distance between the object and the scanning module in Figure 8 (b) is represented as d2. And d1 < d2. Since the distance d2 is farther, the time from the reflector surface reflecting the light beam to the object to the reflected echo light beam is longer, so the rotation angle of the position of the reflector surface from ② to ① is larger. Therefore, the angular offset of the propagation direction of the reflected echo light beam is larger.

[0094] The angular offset in the propagation direction of the echo beam causes the beam's angle to shift after it is reduced by the lens, making it misaligned with the optical fiber at circulator port 2. This reduces the amount of light coupled into the fiber. Furthermore, the greater the angular offset, the lower the light energy coupled into the fiber, affecting the accuracy of subsequent functions.

[0095] It is understood that the above-mentioned Figures 7 and 8 are merely illustrative and do not constitute a limitation on the embodiments of the present application. In a specific implementation, the structure of the detection device system can be any other structure including a scanning module. In addition, the detection device system can be, for example, a system with a common transmission and reception path (such as the system shown in Figure 7 above) or a system with different transmission and reception paths (for example, the return beam is reflected by the scanning module into another optical path, which is different from the optical path of the transmitted beam). The embodiments of the present application do not impose any limitations on this.

[0096] Based on the above description, the embodiments of the present application provide an optical system, a detection device, and a terminal, which can compensate for the offset angle of the echo beam propagation direction and optimize the detection accuracy. An exemplary description is given below.

[0097] 9 and 10 , which exemplarily illustrate the structure of an optical system 100 provided in an embodiment of the present application. The optical system 100 may include a scanning module 101 , a first prism module 102 , and a receiver 103 .

[0098] Exemplarily, the scanning module 101 can be used to reflect the light beam reflected or scattered back by the object (referred to as the first light beam for short). In the specific implementation process, the scanning module 101 can be driven by a scanning drive device (not shown in Figures 9 and 10). Exemplarily, the scanning drive device may include a motor, for example. For example, the motor can drive the scanning module to rotate or deflect. Exemplarily, the scanning module may be a scanning mirror or a rotating mirror, etc., which is not limited in the embodiments of the present application. During the operation of the scanning module 101, the first light beam is incident on the scanning module 101, and after being reflected by the scanning module 101, it can propagate in the direction of the first prism module 102.

[0099] Exemplarily, the above-mentioned first prism module 102 may include one or more first prisms. Among them, FIG9 is shown as an example of including one first prism. FIG10 is shown as an example of including three first prisms (see first prism 1021, first prism 1022 and first prism 1023). The embodiment of the present application does not limit the number of first prisms included in the first prism module 102. Exemplarily, the first prism is an anisotropic crystal prism, a glass prism or a transparent plastic prism, etc. Exemplarily, the first prism can be, for example, a wedge-shaped prism or a prism of other shapes. The embodiment of the present application mainly introduces the wedge-shaped prism as an example.

[0100] The polarization direction of the first light beam is non-perpendicular to the optical axis of any first prism. Based on the above introduction to the refraction of e-light, it can be seen that the refractive index of a light beam whose polarization direction is not perpendicular to the optical axis of the first prism after entering the first prism can be determined based on the incident direction (i.e., the incident angle) of the light beam. Therefore, the first prism module 102 can be used to adjust the propagation direction of the reflected first light beam. That is, the refraction generated after the first light beam enters the first prism is equivalent to the refraction of e-light, which satisfies the refraction law of e-light.

[0101] For example, as shown in Figures 9 and 10, the first prism module 102 includes a first plane and a second plane. In a specific implementation, the first light beam reflected by the scanning module 101 can be incident from the first plane of the first prism module 102 along a first propagation direction. After being emitted from the second plane of the first prism module 102, it propagates along a second propagation direction. Specifically, the first light beam is incident from the first plane at a first incident angle and is emitted from the second plane at a first exit angle. The first plane serves as the incident plane for the first light beam, and the second plane serves as the exit plane for the first light beam.

[0102] Exemplarily, if the first prism module 102 includes a single first prism, the first plane and the second plane belong to the plane of the first prism, as shown in FIG9 . Alternatively, if the first prism module 102 includes multiple first prisms (see, for example, FIG10 ), the first plane belongs to the plane of one of the multiple first prisms (e.g., first prism 1021 shown in FIG10 ). The second plane belongs to the plane of another first prism (e.g., first prism 1023 shown in FIG10 ) among the multiple first prisms. The first light beam passes through the multiple first prisms. The other first prism is the first prism that the first light beam last passes through.

[0103] Exemplarily, the receiver 103 may be configured to receive the first light beam passing through the first prism module 102. Exemplarily, the receiver 103 may include a receiving optical fiber and a detector. The receiving optical fiber may be configured to receive the first light beam and transmit the first light beam to the detector for photoelectric detection. Optionally, the receiver may further include other devices. For example, taking the system shown in FIG. 7 as an example, the receiver 103 may include the circulator, coupler, and detector shown in FIG. 7 , etc., which are not limited in this embodiment of the present application.

[0104] Exemplarily, the detector may be a photodetector. The photodetector includes, but is not limited to, a single-photon avalanche diode (SPAD), a silicon photomultiplier (SiPM), a multi-pixel photon counter (MPPC), a semiconductor avalanche photodiode (APD), or a positive-intrinsic-negative (PIN) diode (or a P-type semiconductor-impurity-N-type semiconductor diode). It will be understood that this is merely an example, and the embodiments of the present application do not limit the specific form or type of the receiver.

[0105] In the above-mentioned optical system 100, the propagation direction of the echo light beam (such as the above-mentioned first light beam) is adjusted by the above-mentioned first prism module. Specifically, since the refractive index of the first prism in the first prism module can be adjusted by changing the first propagation direction (or incident angle) of the light beam, a reasonable selection of the first propagation direction (incident angle) of the light beam can make the propagation direction of the light beam emitted from the first prism module meet the propagation direction compensation (angle compensation) requirements. Thereby, the propagation direction angle deviation caused by the scanning module is compensated, and the light energy of the echo light beam received by the receiver can be increased, so as to obtain more information and improve the detection accuracy. Furthermore, compensating for the propagation direction angle deviation caused by the scanning module by the first prism has the characteristics of easy implementation and low cost, and the angle deviation can be reduced by several times.

[0106] In addition, in the above-mentioned optical system 100, the first prism module 102 may include one or more first prisms. In a specific implementation, since the angle compensation of a first prism is limited, if the angle offset compensation caused by the scanning module can be achieved by using a first prism, then the first prism module 102 may include a first prism. If the angle offset caused by the scanning module is large, and the use of a first prism can no longer meet the compensation requirements, then multiple first prisms can be used. The specific number used can be determined according to demand, and the embodiment of the present application does not impose any restrictions on this. It can be seen that the solution of the embodiment of the present application is used to achieve the angle offset compensation, and the number of first prisms can be flexibly adjusted to meet different compensation requirements, and the application scenarios are wide.

[0107] In one possible implementation, due to the different distances between the object and the scanning module, the time required for the light beam to be reflected or scattered back to the scanning module by the object is different, and thus the angle at which the scanning module moves during this process is also different. Therefore, the scanning angle of the light beam reflected by the scanning module 101 is also different. The angular offset of the light beam after being reflected by the scanning module will also be different. In an embodiment of the present application, when the scanning module 101 reflects the first light beam at different scanning angles, the receiver 103 can receive the first light beam emitted from the first prism module. For ease of understanding, please refer to FIG9A for example. Compared with FIG9 above, FIG9A shows that after the first light beam is reflected by the scanning module 101, it can be incident from the second plane at an angle different from the first incident angle. Then, it is emitted from the second plane at another exit angle. The emitted light beam can still be well received by the receiver 103. That is, the first prism module also achieves compensation for the propagation direction offset angle of the first light beam.

[0108] In a possible implementation, the optical system 100 shown in Figures 9 and 10 can be applied to a detection device with a common transmission and reception path.

[0109] As can be seen in FIG. 11 and FIG. 12 , the optical system 100 may further include a transmitter 104 , a polarization beam splitter (PBS) 105 , a polarization adjuster 106 , and a beam aperture adjuster 107 .

[0110] For example, the transmitter 104 can be used to emit a laser beam (referred to as the second light beam). The transmitter can be, for example, a laser or a laser array, etc., which is not limited in the present embodiment. For example, the frequency of the light beam emitted by the transmitter 104 can be continuously variable, such as a frequency modulated continuous wave (FMCW) laser.

[0111] Exemplarily, the above-mentioned polarization beam splitter 105 can be used to achieve the separation of polarized light. Specifically, polarized light in the first polarization direction cannot pass through the polarization beam splitter 105 and is reflected by the polarization beam splitter 105. Polarized light in the second polarization direction can pass through the polarization beam splitter 105. Exemplarily, in a possible implementation, the first polarization direction and the second polarization direction are perpendicular to each other. For example, the polarized light in the first polarization direction can be, for example, P polarized light, and the polarized light in the second polarization direction can be, for example, S polarized light. Or, for example, the polarized light in the first polarization direction can be S polarized light, and the polarized light in the second polarization direction can be, for example, P polarized light. Or, in another possible implementation, the first polarization direction and the second polarization direction can also be two other different polarization directions, and the embodiment of the present application does not limit this. The embodiment of the present application is introduced by taking the first polarization direction and the second polarization direction as an example that are perpendicular to each other.

[0112] Exemplarily, the polarization regulator 106 can be used to adjust the polarization direction of the light beam. The polarization regulator 106 can be, for example, a quarter-wave plate (QWP). The QWP can also be called a quarter phase delay plate. When the light beam passes through the QWP once, the polarization direction of the light beam rotates 45°. If the light beam passes through the QWP twice back and forth, the polarization direction of the light beam rotates 90°. It is understandable that the polarization regulator 106 can also be, for example, a wave plate of other proportions, not limited to a quarter-wave plate. For ease of description, the embodiment of the present application is introduced by taking a quarter-wave plate as an example.

[0113] For example, the beam aperture adjuster 107 can be used to expand or reduce the aperture of the beam. The beam aperture adjuster 107 can be, for example, a Puller beam expander / contractor system or a Galilean beam expander / contractor system, etc., which is not limited in this embodiment of the present application.

[0114] In one possible implementation, the polarization direction of the second light beam emitted by the emitter 104 is the second polarization direction, and thus can pass through the polarization beam splitter 105. Alternatively, by way of example, the second light beam emitted by the emitter 104 can include multiple polarization directions, such as the first polarization direction and the second polarization direction. Then, only the light beam with the second polarization direction can pass through the polarization beam splitter 105. Figures 11 and 12 illustrate an example in which the light beam emitted by the emitter 104 is the second polarization direction, and the second polarization direction is the S polarization direction. For ease of description, the light beam after passing through the polarization beam splitter 105 is still referred to as the second light beam.

[0115] The second light beam passing through the polarization beam splitter 105 is incident on the first prism module 102 along the third propagation direction. For example, referring to Figures 11 and 12, the second light beam is incident on the second plane of the first prism module 102, passes through one or more first prisms of the first prism module 102, and then exits from the first plane and continues to propagate along the fourth propagation direction. Specifically, the second light beam is incident on the second plane at a second incident angle and exits from the first plane at a second exit angle. The second plane serves as the incident plane for the second light beam, and the first plane serves as the exit plane for the second light beam.

[0116] Exemplarily, the polarization direction of the second light beam passing through the polarization beam splitter 105 is the aforementioned second polarization direction. This second polarization direction is perpendicular to the optical axis of each first prism in the first prism module 102. Therefore, the refraction of the second light beam upon entering the first prism and upon exiting the first prism into the air follows the law of refraction.

[0117] In one possible implementation, the second light beam may, for example, be incident perpendicularly on the second plane of the first prism module 102. That is, the third propagation direction is perpendicular to the second plane, and the incident angle of the second light beam from the second plane is zero. In this implementation, the second light beam does not refract when incident from the second plane. However, after the second light beam is incident on the first prism module 102 and passes through one or more first prisms in the first prism module 102, it is refracted when it is emitted from the first plane. Alternatively, in another possible implementation, the incident angle of the second light beam from the second plane may be any angle greater than zero and less than 90°. In this implementation, the second light beam is refracted once when incident from the second plane. After the second light beam passes through one or more first prisms in the first prism module 102, it is refracted a second time when it is emitted from the first plane. That is, the second light beam is refracted twice in the process of passing through the first prism module 102.

[0118] In one possible implementation, in the case where the first prism module 102 includes multiple first prisms, the multiple first prisms can be reasonably placed so that the second light beam is incident vertically on each first prism. For ease of understanding, Figure 12 is used as an example. For example, in Figure 12, the second light beam passing through the polarization beam splitter 105 is incident vertically on the second plane in the first prism module 102, that is, it is incident vertically on the first prism 1023. The second light beam undergoes a first refraction when it exits the first prism 1023, and the refracted second light beam still vertically enters the first prism 1022. The second light beam undergoes a second refraction when it exits the first prism 1022, and the refracted second light beam still vertically enters the first prism 1021. The second light beam undergoes a third refraction when it exits the first prism 1022. The propagation direction after the third refraction is the fourth propagation direction mentioned above. Exemplarily, in order to make the second light beam vertically incident on each of the multiple first prisms, the multiple first prisms can be optimized for two-dimensional arrangement. For example, the position and / or angle of each first prism can be adjusted by moving forward, backward, left, right, up, down, or rotating. The embodiment of the present application does not limit the placement position or angle of each first prism.

[0119] Alternatively, in another possible implementation, the angle of incidence of the second light beam entering each of the plurality of first prisms can be any angle greater than zero and less than 90°. In this implementation, the second light beam undergoes one refraction when entering each first prism and another refraction when exiting each first prism. The angle of incidence of the second light beam entering each first prism can be set according to actual application requirements and is not limited in the embodiments of the application.

[0120] The second light beam passing through the first prism module 102 propagates along the fourth propagation direction to the polarization adjuster 106. After passing through the polarization adjuster 106, the polarization direction of the second light beam is rotated 45°. It then continues to propagate to the beam aperture adjuster 107. After being expanded by the beam aperture adjuster 107, the second light beam is sent to the scanning module 101. It is then reflected by the scanning module 101 onto an external object.

[0121] After being reflected or scattered by the object, an echo beam (i.e., the above-mentioned first beam) is formed. The polarization direction of the first beam remains the same as the polarization direction of the second beam hitting the object. The first beam propagates back to the scanning module 101, and is reflected by the scanning module 101 to the above-mentioned beam aperture adjuster 107. After being narrowed by the beam aperture adjuster 107, the first beam is sent to the polarization adjuster 106. After passing through the polarization adjuster 106, the polarization direction of the first beam rotates 45°. At this time, compared with the second beam before entering the first prism module 102, the polarization direction of the first beam has rotated 90°. That is, after passing through the polarization adjuster 106, the polarization direction of the first beam is perpendicular to the polarization direction of the second beam before entering the first prism module 102 (i.e., the above-mentioned second polarization direction). Then the polarization direction of the first beam after passing through the polarization adjuster 106 can be the above-mentioned first polarization direction.

[0122] After passing through the polarization adjuster 106, the first light beam is incident from the first plane of the first prism module 102. Then, after passing through one or more first prisms of the first prism module 102, it is emitted from the second plane of the first prism module 102 and continues to propagate along the second propagation direction. For example, the first polarization direction is not perpendicular to the optical axis of any first prism. Based on the above introduction to the refraction of e-light, it can be seen that the refractive index of the light beam whose polarization direction is not perpendicular to the optical axis of the first prism after entering the first prism can be determined based on the incident direction (i.e., the incident angle) of the light beam. Therefore, the first prism module 102 can be used to adjust the propagation direction of the first light beam.

[0123] After exiting the second plane of the first prism module 102, the first light beam propagates to the polarization beam splitter 105. Since polarized light in the first polarization direction cannot pass through the polarization beam splitter 105, the first light beam is reflected by the polarization beam splitter 105 to the receiver 103. In Figures 11 and 12, the first polarization direction is shown as the P polarization direction as an example.

[0124] After receiving the first light beam, the receiver 103 performs photoelectric conversion to obtain an electrical signal. The electrical signal is then input into a signal processor (not shown in Figures 11 and 12) for processing to achieve one or more functions including target detection, distance measurement, speed measurement, target tracking, or image recognition.

[0125] Exemplarily, the second propagation direction is the same as the third propagation direction, i.e., the second angle of incidence is the same as the first angle of emission. Alternatively, the angular deviation between the second propagation direction and the third propagation direction is less than an angle threshold, i.e., the angular deviation between the second angle of incidence and the first angle of emission is less than an angle threshold. This angle threshold can be set based on actual application requirements and is not limited in this embodiment of the present application. The smaller the angle threshold, the higher the accuracy of compensation for the angular offset caused by the scanning module, and the better the compensation effect.

[0126] In another possible implementation, the optical system 100 shown in Figures 9 and 10 can be applied to a detection device in which the transmission and reception are not co-pathed.

[0127] As can be seen in FIG. 13 and FIG. 14 , the optical system 100 may further include a transmitter 104 , a polarization adjuster 106 , two beam aperture adjusters 107_1 and 107_2 , and two reflectors 108_1 and 108_2 .

[0128] For example, the emitter 104 may be used to emit a laser beam (referred to as the second light beam). The emitter may be, for example, a laser or a laser array, etc., which is not limited in the present embodiment.

[0129] Exemplarily, the polarization regulator 106 can be used to adjust the polarization direction of the light beam. The polarization regulator 106 can be, for example, a quarter-wave plate (QWP) or a half-wave plate (HWP). The QWP can also be called a quarter-phase delay plate. When the light beam passes through the QWP once, the polarization direction of the light beam rotates 45°. The HWP can also be called a half-phase delay plate. When the light beam passes through the HWP once, the polarization direction of the light beam rotates 90°. It can be understood that the polarization regulator 106 can also be, for example, a wave plate of other proportions, not limited to a quarter-wave plate or a half-wave plate. For ease of description, the embodiment of the present application is introduced as an example of the polarization regulator 106 being a half-wave plate.

[0130] In a possible implementation, the optical system 100 shown in FIG13 and FIG14 may not include the polarization adjuster 106. Please refer to the following description for details.

[0131] For example, the two beam aperture adjusters described above can be used to expand or reduce the aperture of a light beam. Specifically, beam aperture adjuster 107_1 is primarily used to expand the second light beam emitted by emitter 104. Beam aperture adjuster 107_2 is primarily used to reduce the return light beam (e.g., the first light beam described above) reflected by scanning module 101. The two beam aperture adjusters can be, for example, a Puller beam expander / contractor system or a Galilean beam expander / contractor system, etc., which is not limited in this embodiment of the present application.

[0132] Exemplarily, the two reflectors 108_1 and 108_2 may be used to reflect the light beam and change the propagation direction of the light beam.

[0133] In one possible implementation, the polarization direction of the second light beam emitted by the emitter 104 may be, for example, the first polarization direction, or may be, for example, the second polarization direction. Alternatively, the second light beam may be a light beam including multiple polarization directions (for example, including a first polarization direction and a second polarization direction). Exemplarily, if the second light beam is a light beam including multiple polarization directions, then a polarization beam splitter may be added between the emitter 104 and the beam aperture adjuster 107_1. The polarization beam splitter may, for example, pass light in the first polarization direction or the second polarization direction, while filtering out light in other polarization directions. For ease of description, the light beam after passing through the polarization beam splitter is still referred to as the second light beam.

[0134] After being expanded by the beam aperture adjuster 107_1, the second light beam propagates to the reflector 108_1. After being reflected by the reflector 108_1, the second light beam is sent to the scanning module 101. After being reflected by the scanning module 101, it is reflected onto an external object. After being reflected or scattered by the object, an echo beam (i.e., the first light beam described above) is formed. The polarization direction of the first light beam remains the same as the polarization direction of the second light beam that hit the object. The first light beam propagates back to the scanning module 101 and is reflected by the scanning module 101 onto the reflector 108_2. The reflector 108_2 reflects the first light beam back to the beam aperture adjuster 107_2.

[0135] In one possible implementation, if the polarization direction of the first light beam is non-perpendicular to the optical axis of any first prism in the first prism module 102, the refraction generated in the process of the first light beam passing through the first prism module 102 can satisfy the above-mentioned refraction law of e-light. There is no need to adjust the polarization direction of the first light beam. Therefore, there is no need to set the above-mentioned polarization regulator 106. After the first light beam is narrowed by the above-mentioned beam aperture regulator 107_2, it is sent to the first prism module 102. Specifically, the first light beam can be incident from the first plane of the first prism module 102 along the first propagation direction. Then, after passing through one or more first prisms of the first prism module 102, it is emitted from the second plane of the first prism module 102 and continues to propagate along the second propagation direction.

[0136] Alternatively, in another possible implementation, if the polarization direction of the first light beam is perpendicular to the optical axis of any first prism in the first prism module 102, the polarization direction of the first light beam can be adjusted by the above-mentioned polarization adjuster 106. Specifically, the first light beam is sent to the polarization adjuster 106 after being narrowed by the above-mentioned beam aperture adjuster 107_2. After the polarization direction is adjusted by the polarization adjuster 106 so as to be non-perpendicular to the optical axis, the first light beam is sent to the first prism module 102. Specifically, the first light beam can be incident from the first plane of the first prism module 102 along the first propagation direction. Then, after passing through one or more first prisms of the first prism module 102, it is emitted from the second plane of the first prism module 102 and continues to propagate along the second propagation direction.

[0137] After exiting the second plane of the first prism module 102, the first light beam is sent to the receiver 103. After receiving the first light beam, the receiver 103 performs photoelectric conversion to obtain an electrical signal. The electrical signal is then input into a signal processor (not shown in Figures 13 and 14) for processing to achieve one or more functions including target detection, distance measurement, speed measurement, target tracking, or image recognition.

[0138] In one possible implementation, the first light beam may, for example, be emitted vertically from the second plane of the first prism module 102. That is, the second propagation direction is perpendicular to the second plane, and the angle of emergence of the first light beam from the second plane is zero. In this implementation, the first light beam undergoes one refraction when incident from the first plane. After the first light beam is incident on the first prism module 102 and passes through one or more first prisms in the first prism module 102, no refraction occurs when it is emitted from the second plane. Alternatively, in another possible implementation, the angle of emergence of the first light beam from the second plane may be any angle greater than zero and less than 90°. In this implementation, the first light beam undergoes one refraction when incident from the first plane. After the first light beam passes through one or more first prisms in the first prism module 102, a second refraction occurs when it is emitted from the second plane. That is, the first light beam undergoes two refractions in the process of passing through the first prism module 102.

[0139] In one possible implementation, for the case where the first prism module 102 includes multiple first prisms, the multiple first prisms can be reasonably placed so that the first light beam is emitted vertically from each first prism. For ease of understanding, Figure 14 is used as an example. For example, in Figure 14, the above-mentioned first light beam is incident on the first plane in the first prism module 102, that is, it is incident on the first prism 1021. After emission and refraction, it is emitted vertically from the first prism 1021. The first light beam after emitting the first prism 1021 is incident on the first prism 1022, and after emission and refraction, it is emitted vertically from the first prism 1022. The first light beam after emitting the first prism 1022 is incident on the first prism 1023, and after emission and refraction, it is emitted vertically from the first prism 1023. Exemplarily, in order to make the first light beam emit vertically from each first prism of the multiple first prisms, the multiple first prisms can be optimized for two-dimensional arrangement. For example, the position and / or angle of each first prism can be adjusted by moving forward, backward, left, right, up, down, or rotating. The embodiment of the present application does not limit the placement position or angle of each first prism.

[0140] Alternatively, in another possible implementation, the angle of emission of the first light beam from each of the plurality of first prisms may be any angle greater than zero and less than 90°. In this implementation, the first light beam undergoes a single refraction upon entering each first prism and a single refraction upon exiting each first prism. The angle of emission of the first light beam from each first prism may be set based on actual application requirements and is not a limitation in the embodiments of the present application.

[0141] In the above embodiment, the propagation direction angle deviation caused by the scanning module is compensated by the first prism module 102, thereby increasing the light energy of the echo light beam received by the receiver, so as to obtain more information and improve detection accuracy.

[0142] For example, prism refraction can expand or shrink the light beam, which is related to the prism material, refractive index, and prism wedge angle. In one possible implementation, the beam aperture will become smaller after the light beam passes through the first prism module 102. In order to reduce the impact of the first prism module 102 on the beam aperture, the second prism module can be used to compensate for the beam aperture. For ease of understanding, please refer to Figures 15 and 16 for example.

[0143] FIG15 takes the optical system 100 shown in FIG11 as an example. FIG16 takes the optical system 100 shown in FIG12 as an example. It can be seen that the optical system 100 also includes a second prism module 109. The second prism module 109 may include a second prism, as shown in FIG15 . Alternatively, as shown in FIG16 , the second prism module 109 may include a plurality of second prisms (e.g., a second prism 1091, a second prism 1092, and a second prism 1093, with three prisms shown as an example). For example, the second prism may be, for example, an isotropic glass prism or a transparent plastic prism. For example, the second prism may be, for example, a wedge-shaped prism or a prism of other shapes. The embodiments of the present application are mainly introduced by taking a wedge-shaped prism as an example. Regarding the refraction of the light beam by the second prism, reference may be made to the above-mentioned introduction to the refraction of light by an isotropic wedge-shaped prism, which will not be repeated here.

[0144] For example, the shape and size of the second prism can be the same as or different from those of the first prism. For example, as shown in FIG15 or FIG16 , the arrangement of the second prism module 109 can be considered to be the result of rotating the first prism module 102 180° to the left or right and replacing the first prism in the first prism module 102 with the second prism. For example, the second prism module 109 is disposed between the polarization adjuster 106 and the first prism module 102.

[0145] Exemplarily, the refractive index of the second prism with respect to the first light beam is the same as the refractive index of the first prism in the first prism module 102 with respect to the first light beam. Alternatively, exemplarily, the deviation between the refractive index of the second prism with respect to the first light beam and the refractive index of the first prism in the first prism module 102 with respect to the first light beam is less than a preset threshold. The preset threshold can be set according to actual application and is not limited in this embodiment of the present application.

[0146] For example, since the prism wedge angle also affects the aperture of the light beam, in a specific implementation, a suitable wedge angle of the second prism can be selected according to actual application needs, and the embodiments of the present application do not limit this.

[0147] For example, in the optical system 100 shown in Figures 15 and 16, the first light beam passes through the polarization adjuster 106 and is then sent to the second prism module 109. The aperture of the first light beam output after refraction by the second prism module 109 is increased. For example, the first light beam can be incident from the third plane of the second prism module 109 (for example, the third plane of the second prism in Figure 15, or the third plane of the second prism 1091 in Figure 16), pass through one or more second prisms, and then exit the second prism module 109 from the fourth plane (for example, the fourth plane of the second prism in Figure 15, or the fourth plane of the second prism 1093 in Figure 16). Specifically, the third plane is the incident plane for the first light beam, and the fourth plane is the exit plane for the first light beam.

[0148] The first light beam, with its increased aperture, then propagates to the first prism module 102. The aperture of the first light beam is reduced after passing through the first prism module 102. With this structural design, and the refractive index of the second prism for the first light beam being the same as or slightly different from that of the first prism, the second prism module 109 can compensate for the reduced beam aperture caused by the first prism module 102.

[0149] In one possible implementation, the second prism module 109 and the first prism module 102 cooperate to ensure that the propagation direction of the light beam emitted from the first prism module 102 is parallel to the propagation direction of the light beam incident on the second prism module 109, or the deviation angle is less than a preset angle threshold. The preset angle threshold can be set according to actual conditions and is not limited in this embodiment of the present application.

[0150] Illustratively, in the optical system 100 shown in Figures 15 and 16 above, the second light beam passes through the polarization beam splitter 105 and is then sent to the first prism module 102. The aperture of the second light beam output after refraction by the first prism module 102 is reduced. Then, the second light beam with a reduced aperture propagates to the second prism module 109. Illustratively, the second light beam can be incident from the fourth plane of the second prism module 109 (e.g., the fourth plane of the second prism in Figure 15, or the fourth plane of the second prism 1093 in Figure 16), and after passing through one or more second prisms, it can be emitted from the second prism module 109 from the third plane (e.g., the third plane of the second prism in Figure 15, or the third plane of the second prism 1091 in Figure 16). Specifically, the fourth plane is the incident plane for the second light beam, and the third plane is the exit plane for the second light beam.

[0151] The aperture of the second light beam increases after passing through the second prism module 109. With this structural design, and the refractive index of the second prism for the second light beam being the same as or slightly different from that of the first prism for the second light beam, the second prism module 109 can compensate for the reduced beam aperture caused by the first prism module 102.

[0152] In one possible implementation, the second prism module 109 and the first prism module 102 cooperate to ensure that the propagation direction of the light beam emitted from the second prism module 109 is parallel to the propagation direction of the light beam incident on the first prism module 102, or the deviation angle is less than a preset angle threshold. The preset angle threshold can be set according to actual conditions and is not limited in this embodiment of the present application.

[0153] An embodiment of the present application further provides a detection device, which includes the optical system 100 described in any possible embodiment described above.

[0154] The embodiment of the present application further provides a terminal, which includes the optical system 100 described in any possible embodiment described above. Alternatively, the terminal includes the detection device described above.

[0155] Exemplarily, the terminal can be an intelligent terminal or means of transportation such as a vehicle, a drone, or a robot. Of course, the terminal can also be replaced by industrial equipment, entertainment and leisure equipment, etc. Intelligent terminals include mobile phones, tablet computers, laptops, smart bracelets, smart watches, or smart glasses. Transportation tools include vehicles, ships, aircraft, or logistics robots. Industrial equipment includes industrial robots and robotic arms. Leisure and entertainment equipment includes virtual reality (VR) equipment, mixed reality (MR) equipment, massage chairs, or 4D cinema cabins. This application does not impose strict restrictions on the devices to which the electrical connector can be applied.

[0156] In summary, the optical system, detection device and terminal provided in the present application can compensate for the offset angle of the echo light beam propagation direction and optimize the detection accuracy.

[0157] It should be understood that in the various embodiments of the present application, the size of the serial number of each process does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0158] It will also be understood that the term “comprise” (also known as “includes,” “including,” “comprises,” and / or “comprising”) when used in this specification specifies the presence of stated features, integers, steps, operations, elements, and / or components, but does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0159] It should also be understood that references throughout this specification to "one embodiment," "an embodiment," or "one possible implementation" mean that specific features, structures, or characteristics associated with that embodiment or implementation are included in at least one embodiment of the present application. Therefore, the appearance of "in one embodiment," "in an embodiment," or "one possible implementation" throughout this specification does not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0160] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. An optical system, characterized in that: The optical system includes a scanning module, a first prism module and a receiver, the first prism module includes one or more first prisms, and the first prism module includes a first incident surface and a first exit surface; The scanning module is used to reflect a first light beam, wherein the first light beam includes a light beam reflected or scattered by an object; The first prism module is used to adjust the propagation direction of the first light beam after reflection; the first light beam after reflection is incident from the first incident surface at a first incident angle and is emitted from the first exit surface; the refractive index of the first light beam in the one or more first prisms is related to the first incident angle; The receiver is used to receive the first light beam emitted from the first prism module.

2. The optical system according to claim 1, wherein: The first prism is an anisotropic crystal prism.

3. The optical system according to claim 1 or 2, characterized in that The polarization direction of the first light beam is non-perpendicular to the optical axis of the first prism.

4. The optical system according to any one of claims 1 to 3, characterized in that: The refraction generated when the reflected first light beam is incident on the first incident surface is the refraction of extraordinary light.

5. The optical system according to any one of claims 1 to 4, characterized in that: When the scanning module is used to reflect the first light beam at different scanning angles, the receiver receives the first light beam emitted from the first prism module.

6. The optical system according to any one of claims 1 to 5, characterized in that: The receiver includes a receiving optical fiber and a detector.

7. The optical system according to any one of claims 1 to 6, characterized in that: If the first prism module includes a first prism, the first incident surface and the first exit surface are flat or curved surfaces of the first prism; If the first prism module includes multiple first prisms, the first incident surface belongs to the plane or curved surface of one first prism among the multiple first prisms, the first exit surface belongs to the plane or curved surface of another first prism among the multiple first prisms, and the first light beam passes through the multiple first prisms.

8. The optical system according to any one of claims 1 to 7, characterized in that: The optical system further includes a second prism module, which is used to expand the aperture of the first light beam; the second prism module includes one or more second prisms; The second prism module includes a second incident surface and a second exit surface; the first light beam reflected by the scanning module is incident from the second incident surface, and after being emitted from the second exit surface, it is incident on the first prism module from the first incident surface at the first incident angle; the aperture of the first light beam emitted from the second exit surface is larger than the aperture of the first light beam incident from the second incident surface.

9. The optical system according to claim 8, wherein: The refractive index of the first light beam in the one or more second prisms is the same as the refractive index of the first light beam in the one or more first prisms; or A deviation between a refractive index of the first light beam in the one or more second prisms and a refractive index of the first light beam in the one or more first prisms is smaller than a preset threshold.

10. The optical system according to claim 8 or 9, characterized in that The second prism is an isotropic glass prism or a transparent plastic prism.

11. The optical system according to any one of claims 1 to 10, characterized in that: The optical system further includes a polarization adjuster, configured to adjust the polarization direction of the first light beam to a first polarization direction; The first light beam incident on the first incident surface is a light beam whose polarization is adjusted by the polarization adjuster.

12. The optical system according to claim 11, wherein: The polarization adjuster is a quarter wave plate or a half wave plate.

13. The optical system according to any one of claims 1 to 12, characterized in that: The optical system further includes a beam aperture adjuster, which is used to reduce the aperture of the first light beam; The first light beam incident on the first prism module is a light beam whose aperture is reduced by the beam aperture adjuster.

14. The optical system according to claim 13, wherein: The beam aperture adjuster includes a Kepler beam expansion / contraction system or a Galilean beam expansion / contraction system.

15. The optical system according to any one of claims 1 to 14, characterized in that: The optical system further includes a polarization beam splitter configured to reflect the first light beam in a first polarization direction to the receiver.

16. The optical system according to any one of claims 1 to 15, characterized in that: The optical system further includes a reflector, which is used to reflect the first light beam reflected from the scanning module so that the first light beam propagates in the direction of the first prism module.

17. The optical system according to any one of claims 1 to 16, characterized in that: The first light beam is emitted from the first exit surface at a first exit angle; The optical system further includes an emitter for emitting a second light beam; the first exit surface is an incident surface for the second light beam, and the first incident surface is an exit surface for the second light beam; The first prism module is further used to adjust the propagation direction of the second light beam; the second light beam is incident from the first exit surface at a second incident angle and is emitted from the first incident surface; The second incident angle is the same as the first exit angle, or an angular deviation between the second incident angle and the first exit angle is less than an angle threshold.

18. The optical system according to claim 17, wherein: The polarization direction of the second light beam is perpendicular to the polarization direction of the first light beam.

19. The optical system according to any one of claims 1 to 18, characterized in that: The first light beam is emitted from the first emission surface at an emission angle of 90°.

20. A detection device, characterized in that: The detection device comprises the optical system according to any one of claims 1-19.

21. A terminal, characterized in that: The terminal includes the optical system according to any one of claims 1 to 19; or, includes the detection device according to claim 20.

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