A laser radar optical receiving system

Abstract

The present invention discloses a laser radar optical receiving system, comprising: a laser radar receiving lens, which is used to converge the incident light signal and focus the output; a detection unit, which is used to receive the light signal focused and output by the laser radar receiving lens; the focal plane formed by the focusing of the laser radar receiving lens is located on the receiving surface of the detection unit and the focal plane is equal to or smaller than the photosensitive element area of ​​the receiving surface of the detection unit. In the system of the present invention, the laser radar lens converges and collimates the information of the large field of view angle through the lens, and then converges it to the laser radar receiving system of a single detector. It satisfies the reception of height information perpendicular to the laser radar emission plane, reduces the number of detectors used in the laser radar system, and meets the miniaturization requirements of the laser radar. In addition, the use of a single detection element allows the package size to be miniaturized, solves the high cost problem of linear or array detection units, and promotes the real civilian use of laser radar.

Description

Technical Field

[0001] The present invention belongs to the field of laser communication devices, especially to the field of laser communication devices that can be used for unmanned driving of automobiles, robot reconnaissance, unmanned aerial vehicle detection, automatic sweepers and other equipment, and specifically relates to a laser radar optical receiving system. Background Art

[0002] Laser radar is a radar that works in the optical frequency band. It uses electromagnetic waves in the optical frequency band to first transmit a detection signal to the target, and then reflects the received signal of the same wave back and processes the information with the transmitted signal, so as to obtain the target's position (distance, direction and altitude), motion state (speed, posture) and other information, and realize the detection, tracking and identification of the target. Due to its high speed, strong anti-interference ability, simple structure and easy use, laser radar has been increasingly widely used and continuously expanded in various fields of military and civilian production and life, becoming an indispensable high-tech means in social development services. With the current upsurge in the development of artificial intelligence technology, laser radar has gained unprecedented favor in the fields of unmanned driving of cars, drones, smart sweeping robots, etc., opening up a broad market for the application of laser radar.

[0003] At present, an important indicator of laser radar is the number of lines. According to the number of lines, there are common single-line, 4-line, 16-line, 32-line, 64-line, 128-line, etc. Since the data of single-line laser radar lacks a dimension, it can only describe linear information, not surface. Therefore, it is impossible to obtain the height information of the object perpendicular to the laser radar emission plane. Multi-line radar is currently the most important radar used in fields such as autonomous driving, but the price is extremely high. A 64-line laser radar costs up to tens of thousands of dollars. The main reason for its high cost is that the number of detectors required for the number of laser radars used is complicated, and the arrangement of multiple detectors is cumbersome and relatively expensive. Therefore, the price of multi-line laser radar is expensive, which also limits the development of civilian use to a certain extent. Reducing the number of detectors used as much as possible and adopting consumer-grade detectors will be the key technology to promote lasers into real civilian use. Summary of the invention

[0004] In view of the prior art, the purpose of the present invention is to provide a laser radar optical receiving system with narrow-band filtering function, which has small size, small distortion, large angle range, large light flux, high light spot uniformity and low noise interference. The system is suitable for laser radar ranging reception and laser radar mapping system reception, and is used in unmanned driving of automobiles, robot reconnaissance, drone detection, automatic sweepers, etc.

[0005] In order to achieve the above technical objectives, the technical solution adopted by the present invention is:

[0006] A laser radar optical receiving system, comprising:

[0007] The laser radar receiving lens is used to gather the incident light signal and focus the output;

[0008] A detection unit, used to receive the optical signal focused and output by the laser radar receiving lens;

[0009] The focal plane formed by focusing the laser radar receiving lens is located on the receiving surface of the detection unit and the focal plane is equal to or smaller than the photosensitive element area of ​​the receiving surface of the detection unit.

[0010] The main function of the laser radar receiving lens of this scheme is to focus the light signals received in a large field of view into a very small range of the focal plane, and its focusing range is no larger than the photosensitive element area of ​​the selected detection unit; in addition to its main function, any optical or mechanical components that improve optical performance or achieve special purposes can be added, including but not limited to optical filters, apertures, windows, etc.; and the detection unit can be a detection element of any working principle and model.

[0011] As a possible implementation mode, further, the laser radar receiving lens includes a first focusing lens group, a filter, a fixed aperture, a first collimating lens group and a second focusing lens group arranged in sequence along the optical path, wherein the first focusing lens group is a negative focal length focusing lens group, and the second focusing lens group is a positive focal length focusing lens group, and the light signal received by the first focusing lens group passes through the filter, the fixed aperture, the first collimating lens group and the second focusing lens group in sequence, and is focused and output by the second focusing lens group.

[0012] As a possible option, preferably, the first focusing lens group is used to converge light signals in a large angle range along the incident direction, and includes a first lens and a second lens arranged in sequence, the first lens is a meniscus lens, the second lens is a biconcave lens, and a first mechanical spacer is provided between the first lens and the second lens.

[0013] As a possible option, preferably, the first collimating lens group is used to collimate the optical signal input by the first focusing lens group, and includes a third lens, and the third lens is a biconvex lens.

[0014] As a possible option, preferably, the second focusing lens group is used to converge the light signal collimated by the first collimating lens group, so that the light signal is converged within a focal plane of an extremely small area and is received by the detection unit, and it includes a fourth lens and a fifth lens arranged in sequence, the fourth lens is a biconvex lens, and the fifth lens is a meniscus lens.

[0015] As a possible option, preferably, the filter is an optical flat plate.

[0016] As a possible option, preferably, the system also includes a mechanical lens barrel that relatively fixes and packages the first focusing lens group, the filter, the fixed aperture, the first collimating lens group and the second focusing lens group, and the detection unit is arranged on the end of the mechanical lens barrel corresponding to the second focusing lens group.

[0017] As a possible option, more preferably, the mechanical lens barrel is a cylindrical structure with both ends open, and the first focusing lens group, filter, fixed aperture, first collimating lens group, second focusing lens group and detection unit are arranged in sequence in the cylindrical structure of the mechanical lens barrel, and a front pressure ring is connected to the end of the mechanical lens barrel close to the first focusing lens group.

[0018] As a possible option, more preferably, a second mechanical spacer is provided between the corresponding filter and the fixed aperture in the mechanical lens barrel, a mechanical aperture spacer is provided between the fixed aperture and the first collimating lens group, and a third mechanical spacer is provided between the first collimating lens group and the second focusing lens group.

[0019] As a possible implementation manner, further, a shrinkage structure is provided between the second focusing lens group and the detection unit in the mechanical lens barrel.

[0020] As a possible implementation manner, further, the detection unit is a single APD device, and the diameter of the photosensitive element thereof does not exceed 500 um.

[0021] The principle of the laser radar optical receiving system of the present invention is as follows:

[0022] Light within the large-angle field of view at the front end of the laser radar lens is incident on the laser radar receiving lens, which converges and compresses the incident light within the large field of view, collimates the converged and compressed light, and then converges the collimated light into an extremely small light spot again, so that the light spot size is less than or equal to the detection face element of a single detector, so that a single detector can be used to receive the incident signal within the large field of view angle range, and transmit the received information to the callback detection processing system.

[0023] By adopting the above technical scheme, the present invention has the following beneficial effects compared with the prior art: the present scheme has an ultra-small size, a large angle range of the field of view of the received light, a large lens light flux, small distortion, high uniformity of the light spot, and low noise interference; the light in a large angle range at the front end of the lens is incident on the receiving lens, and after passing through the lens, it is converged within the effective photosensitive area of ​​a single detection unit (the photosensitive surface element of a conventional detector is extremely small), completing the reception of height information perpendicular to the laser radar emission plane within a large angle field of view, and the received information is converted into an electrical signal and transmitted to the back-end for processing;

[0024] Its advantages can also be briefly summarized into the following two points:

[0025] (1) The laser radar lens in the system of the present invention gathers, collimates, and then converges the wide field of view angle information to a laser radar receiving system with a single detector. This satisfies the requirement of receiving height information perpendicular to the laser radar emission plane, reduces the number of detectors used in the laser radar system, and meets the miniaturization requirements of the laser radar.

[0026] (2) The system of the present invention adopts a single detection element, which overcomes the problem of large package size caused by multiple (linear or array) detection units in conventional receiving systems. It further solves the high cost problem of linear or array detection units, and promotes the real civilian use of laser radar. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments:

[0028] Figure 1 A schematic diagram of the light path principle of the solution of the present invention;

[0029] Figure 2 A schematic diagram of the simplified coordination between the laser radar receiving lens and the inference unit of the present invention;

[0030] Figure 3 The schematic diagram is a simplified implementation structure diagram of the present invention packaged in a mechanical lens barrel. DETAILED DESCRIPTION

[0031] like Figures 1 to 3 As shown in one, the laser radar optical receiving system of the present invention comprises:

[0032] The laser radar receiving lens is used to gather the incident light signal and focus the output;

[0033] A detection unit 6, used to receive the optical signal output by the laser radar receiving lens;

[0034] The focal plane formed by focusing the laser radar receiving lens is located on the receiving surface of the detection unit 6 and the focal plane is equal to or smaller than the photosensitive element area of ​​the receiving surface of the detection unit 6.

[0035] Among them, the laser radar receiving lens includes a first focusing lens group 1, a filter 2, a fixed aperture 3, a first collimating lens group 4 and a second focusing lens group 5 arranged in sequence along the optical path, wherein the first focusing lens group 1 is a negative focal length focusing lens group, and the second focusing lens group 5 is a positive focal length focusing lens group. The optical signal received by the first focusing lens group 1 passes through the filter 2, the fixed aperture 3, the first collimating lens group 4 and the second focusing lens group 5 in sequence, and is focused and output by the second focusing lens group 5.

[0036] As a possible option, preferably, the first focusing lens group 1 is used to converge light signals in a large angle range along the incident direction, and includes a first lens 101 and a second lens 102 arranged in sequence, wherein the first lens 101 is a meniscus lens, and the second lens 102 is a double concave lens.

[0037] As a possible option, preferably, the first collimating lens group 4 is used to collimate the optical signal input by the first focusing lens group 1, and includes a third lens, and the third lens is a biconvex lens.

[0038] As a possible option, preferably, the second focusing lens group 5 is used to converge the light signal collimated by the first collimating lens group 1, so that the light signal is converged within a focal plane of an extremely small area and is received by the detection unit 6, which includes a fourth lens 501 and a fifth lens 502 arranged in sequence, the fourth lens 501 is a biconvex lens, and the fifth lens 502 is a meniscus lens.

[0039] As a possible option, preferably, the filter 2 is an optical flat plate.

[0040] In this solution, the laser radar receiving lens has a first focusing lens group 1 at the front end of the lens, which is used to receive light signals in a large field of view angle range. Finally, after passing through the second focusing lens group 5, the light signals in the entire field of view are converged within an extremely small focal plane and overlap with the photosensitive unit of the detection unit of this system solution. The detector unit 6 described in this solution can be a single APD or a single group of detector units of any other model and specification.

[0041] In this embodiment, the first lens 101, the second lens 102, the filter 2, the fixed aperture 3, the third lens, the fourth lens 501 and the fifth lens 502 are arranged in sequence, and the fourth lens 501 and the fifth lens 502 are glued together. Each lens should meet the following optical conditions:

[0042] 1.5 <n1<1.95,20<v1<65;

[0043] 1.7 <n2<1.95,20<v2<50;

[0044] 1.7 <n3<2.0,20<v3<40;

[0045] 1.55 <n4<1.65,60<v4<70;

[0046] 1.8 <n5<1.9,20<v5<35;

[0047] Wherein, n1, n2, n3, n4, n5 are refractive indices of the first lens 101, the second lens 102, the third lens, the fourth lens 501 and the fifth lens 502 respectively, and v1, v2, v3, v4, v5 are Abbe numbers of the first lens 101, the second lens 102, the third lens, the fourth lens 501 and the fifth lens 502 respectively.

[0048] As a possible option, preferably, the system also includes a mechanical barrel 7 that relatively fixes and packages the first focusing lens group 1, the filter 2, the fixed aperture 3, the first collimating lens group 4 and the second focusing lens group 5, and the detection unit 6 is arranged on the end of the mechanical barrel 7 corresponding to the second focusing lens group 5; more preferably, the mechanical barrel 7 is a cylindrical structure with two ends open, and the first focusing lens group 1, the filter 2, the fixed aperture 3, the first collimating lens group 4, the second focusing lens group 5 and the detection unit 6 are arranged in sequence in the cylindrical structure of the mechanical barrel 7, and a front pressure ring 8 is connected to the end of the mechanical barrel 7 close to the first focusing lens group, and the front pressure ring 8 plays a role in limiting the installation of the first focusing lens group 1 of the laser radar receiving lens at the front end of the mechanical barrel 7.

[0049] As a possible option, more preferably, a first mechanical spacer 12 is provided in the mechanical lens barrel 7 between the first lens 101 and the second lens 102, a second mechanical spacer 9 is provided between the filter 2 and the fixed aperture 3, and a mechanical aperture spacer 10 is provided between the fixed aperture 3 and the first collimating lens group 4. The second mechanical spacer 9 and the mechanical aperture spacer 10 work together to position the air gap between the filter 2 and the first collimating lens 4 and the aperture through which light passes. In addition, the filter 2 is placed at a relatively minimum angle of incidence of light, and a third mechanical spacer 11 is provided between the second lens 102 and the second mechanical spacer 9 and between the first collimating lens group 4 and the second focusing lens group 5. The air gap between the two is limited by the third mechanical spacer 11.

[0050] The filter 2 is placed at a position where the incident angle of the light is relatively minimum, between the second lens 102 and the second mechanical spacer 9, which is beneficial to improving the transmittance of the effective spectrum wavelength and reducing noise interference.

[0051] The first mechanical spacer 12, the second mechanical spacer 9, and the mechanical aperture spacer 10 adopt an "L"-shaped structure; the third mechanical spacer 11 adopts a "convex"-shaped structure.

[0052] As a possible implementation mode, further, a shrinkage structure is provided between the second focusing lens group 5 and the detection unit 6 in the mechanical lens barrel 7. Through this form, the laser radar receiving lens can be directly assembled by loading the components in sequence from the end of the mechanical lens 7 where the front pressure ring 8 is provided, and the front pressure ring 8 can be connected to the mechanical lens barrel 7 by means of threads, and the front pressure ring 8 is abutted against the edge of the first focusing lens group 1, so that the laser radar receiving lens is encapsulated in the mechanical lens barrel 7.

[0053] By adopting the laser radar receiving system of this embodiment, a single detection unit or a very small photosensitive area detector 6 can be used to complete the reception of height information perpendicular to the laser radar emission plane within a large angle field of view, and the received information can be converted into an electrical signal for transmission to the back-end processing.

[0054] It should be noted that variations and modifications of the embodiments disclosed herein are possible, and replacements and equivalent components of the embodiments are well known to those skilled in the art. It should be clear to those skilled in the art that the present invention may be implemented in other forms, structures, arrangements, and proportions without departing from the spirit or essential features of the present invention.

Claims

1. A laser radar optical receiving system, characterized in that: It includes: The laser radar receiving lens is used to gather the incident light signal and focus the output; A detection unit, used to receive the optical signal focused and output by the laser radar receiving lens; The focal plane formed by focusing the laser radar receiving lens is located on the receiving surface of the detection unit and the focal plane is equal to or smaller than the photosensitive element area of ​​the receiving surface of the detection unit; The laser radar receiving lens comprises a first condensing lens group, a filter, a fixed aperture, a first collimating lens group and a second condensing lens group which are sequentially arranged along the optical path, wherein the first condensing lens group is a negative focal condensing lens group, and the second condensing lens group is a positive focal condensing lens group, and the optical signal received by the first condensing lens group passes through the filter, the fixed aperture, the first collimating lens group and the second condensing lens group in sequence, and is focused and output by the second condensing lens group; The first condensing lens group is used to converge the optical signal in a large angle range along the incident direction, and comprises a first lens and a second lens arranged in sequence, the first lens is a meniscus lens, the second lens is a biconcave lens, and a first mechanical spacer is arranged between the first lens and the second lens; The first collimating lens group is used to collimate the optical signal input by the first focusing lens group, and includes a third lens, and the third lens is a biconvex lens; The second focusing lens group is used to converge the light signal collimated by the first collimating lens group, so that the light signal is converged within a focal plane with an extremely small area and is received by the detection unit. It includes a fourth lens and a fifth lens arranged in sequence, the fourth lens is a biconvex lens, and the fifth lens is a meniscus lens.

2. A laser radar optical receiving system according to claim 1, characterized in that: The filter is an optical flat plate.

3. A laser radar optical receiving system according to claim 1, characterized in that: The system also includes a mechanical lens barrel that relatively fixes and packages the first condensing lens group, the filter, the fixed aperture, the first collimating lens group and the second condensing lens group, and the detection unit is arranged on the end of the mechanical lens barrel corresponding to the second condensing lens group.

4. A laser radar optical receiving system according to claim 3, characterized in that: The mechanical lens barrel is a cylindrical structure with both ends open. The first focusing lens group, filter, fixed aperture, first collimating lens group, second focusing lens group and detection unit are arranged in sequence in the cylindrical structure of the mechanical lens barrel, and a front pressure ring is connected to the end of the mechanical lens barrel close to the first focusing lens group.

5. A laser radar optical receiving system according to claim 4, characterized in that: A second mechanical spacer is provided between the corresponding filter and the fixed diaphragm in the mechanical lens barrel, a mechanical diaphragm spacer is provided between the fixed diaphragm and the first collimating lens group, and a third mechanical spacer is provided between the first collimating lens group and the second focusing lens group.

6. A laser radar optical receiving system according to claim 5, characterized in that: A shrinkage structure is provided between the second condensing lens group and the detection unit in the mechanical lens barrel.

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