Laser radar array transmitting and receiving device without mechanical component and assembling, correcting and judging process thereof

Abstract

The invention relates to a laser radar array transceiver without a mechanical component. The laser radar array transceiver comprises a laser transmitting channel, an echo receiving channel, a glass sleeve and the like, the transmitting channel is composed of a transmitting lens, a substrate, a transmitting bottom plate and a transmitting optical fiber glass end, and the echo receiving channel is composed of a receiving lens group, a substrate, a receiving bottom plate and a receiving optical fiber glass end. The fixed combination operation of the optical devices of the transmitting and receiving channels is realized by gluing, no mechanical component is used, and the device has the characteristics of small size, light weight, compactness, high integration level, vibration resistance, no stress influence caused by temperature difference change and the like; the method is suitable for laser communication, radar and laser countermeasure systems of various airborne and no-load platforms.

Description

Technical Field

[0001] The present invention belongs to the field of space laser engineering applications, and relates to a laser radar array transceiver device without mechanical components and its installation, calibration and judgment process. No mechanical components are required, and all optical elements are installed and adjusted by gluing. It has the characteristics of small size, light weight, compactness, high integration, vibration resistance, and no influence of stress caused by temperature difference changes. Background Art

[0002] LiDAR array transmission and reception technology has significant advantages in space laser applications. Array transmission technology improves the detection efficiency and coverage of LiDAR by working multiple transmitting units at the same time. Array receiving technology improves the speed and accuracy of signal processing by working multiple receiving modules in parallel. For example, in synthetic aperture LiDAR, the use of array balanced detectors can achieve coherent transmission and reception, thereby greatly expanding the imaging field of view and improving imaging resolution. This technology not only improves the sensitivity of the system, but also maintains a high data acquisition speed and accuracy in complex environments. LiDAR array transmission and reception technology provides higher detection efficiency, wider coverage, and higher data processing speed and accuracy in space laser applications.

[0003] Traditional laser array transmitting and receiving systems are usually installed and debugged by mechanical fixing, which is easily affected by vibration and temperature changes. The temperature deformation stress of optical glass and mechanical components is different, which will cause changes in the optical axis, etc., thus affecting the accuracy and stability of the system. First, optical glass and mechanical components will deform differently when the temperature changes. For example, the thermal expansion coefficient of hard glass is 4×10 -6 / K, which means that when the temperature changes by 10 degrees, the relative frequency drift is 4×10 -10 The thermal expansion coefficient of quartz material is even lower, only 5×10 -7 / K, so its deformation is smaller under the same temperature change. This material property determines that in an environment with large temperature changes, the deformation difference of optical glass and mechanical components will significantly affect the stability of the optical axis. When the ambient temperature changes, the consistency of multiple optical axes is difficult to ensure, resulting in the offset of wavefront correction reference and tracking zero position, affecting the establishment of communication links.

[0004] Secondly, mechanical fixing methods are prone to stress release and deformation in a vibrating environment. In the study of the two-axis turntable for laser emission, it was found that due to the influence of environmental vibration and gravity, the mechanical devices used to fix the reflector will release stress and deform, causing the array laser to tilt and piston phase difference, reducing the phase control effect. Therefore, in a vibrating environment, the stability of the mechanical fixing method is seriously challenged.

[0005] In the patent of Feng Liang et al., a solution of laser transmitter, laser receiver and laser radar is proposed (see patent application number CN202322845855.1), and a structural design of laser transmitter and laser receiver is proposed. By configuring the thermal expansion coefficient of the second fixing part, it is ensured that when the working environment temperature changes, the laser transmitter and laser receiver can still be aimed at the same target, thereby improving the stability and accuracy of the laser radar in different working environments. In addition, some researchers proposed the use of a precision temperature control system to strictly control the internal temperature fluctuations of the system, reduce the impact of temperature changes on performance, and establish a multi-reflector error transmission model, and conducted an in-depth analysis of the optical axis consistency of the system and conducted experimental verification.

[0006] Although previous studies have attempted to mitigate the impact of temperature changes on the consistency of the optical axis by adjusting the thermal expansion coefficient of fixtures, using precision temperature control systems, and establishing multi-mirror error transfer models, these methods are mostly passive and have limitations. More innovative and efficient technical means are urgently needed to overcome these shortcomings. Summary of the invention

[0007] In order to reduce the deformation of mechanical components used to fasten the transmitting and receiving optical arrays in the space laser engineering system caused by temperature changes and the impact of mechanical vibration on the optical system, the present invention proposes a laser radar array transceiver device without mechanical components and its installation and judgment process. By fixing the optical devices by gluing, the traditional mechanical components are completely abandoned, thereby realizing the miniaturization, lightness, high compactness and high integration of the device. Not only the system's anti-vibration ability and adaptability to temperature difference changes are improved, but also the duty cycle of the optical aperture is significantly improved, and the receiving efficiency is enhanced. It is particularly suitable for laser communication, radar and laser countermeasure systems of airborne and airborne platforms.

[0008] The technical solution of the present invention is as follows:

[0009] On the one hand, the present invention provides a laser radar array transceiver device without mechanical components, which is characterized by comprising:

[0010] A laser emission channel (1), comprising an emission optical fiber plate (7), an emission column (6), and an emission lens on a transceiver lens substrate (3), wherein the emission optical fiber plate (7) is fixed to the emission column (6) by gluing, the other end of the emission column (6) is fixed to the transceiver optical fiber porous plate (4) by gluing, the emission lens is glued and fixed to the center of the transceiver lens substrate (3), and the focal length of the emission lens is determined by the sum of the lengths of the glass sleeve (5) and the emission column (6);

[0011] N laser receiving channels (2), each laser receiving channel (2) comprising a receiving lens arranged on the transceiver lens substrate (3), the focal length of the receiving lens being determined by a glass sleeve (5);

[0012] A transmitting and receiving lens substrate (3), used for supporting a transmitting lens and a receiving lens;

[0013] The transmitting and receiving optical fiber porous plate (4) is used to fix the transmitting column (6) and the optical fiber glass tube of the receiving channel;

[0014] A glass sleeve (5), one end of which is fixed to the transmitting and receiving optical fiber porous plate (4) by gluing, and the other end of which is fixed to the transmitting and receiving lens substrate (3) by gluing, so as to determine the focal length of the transmitting lens and the receiving lens;

[0015] The laser emitting channel (1) is arranged at the center of the transceiver optical fiber porous plate (4), and N laser receiving channels (2) are arranged in a ring shape around the laser emitting channel (1), forming a one-transmit-N-receive transceiver array, where N is an integer greater than or equal to 1.

[0016] Furthermore, after the glass tube of the transmitting optical fiber and the transmitting and receiving porous plate (4) are adjusted to a suitable three-dimensional posture, they are fixed by gluing to ensure the precise alignment of the optical path.

[0017] Furthermore, the receiving lens is glued to the center of the transceiver lens substrate (3), and the focal length of the receiving lens, that is, the distance between the transceiver lens substrate and the transceiver porous plate, is determined by the glass sleeve.

[0018] Furthermore, the outer edge spacing between the laser receiving channels (2) is less than 1 mm.

[0019] Furthermore, it also includes a fine-tuning mechanism for fine-tuning the three-dimensional posture of each optical device. The fine-tuning mechanism is used to ensure the alignment accuracy of each optical device before gluing and is removed during the gluing process.

[0020] Furthermore, the bonding method uses ultraviolet glue or other suitable optical adhesives, and during the bonding process, a suitable auxiliary fixing device is used to ensure the stability of the position of the optical device until the adhesive is cured.

[0021] On the other hand, the present invention also provides a calibration and determination process of a laser radar array transceiver device without mechanical components, which is characterized in that it includes the following steps:

[0022] A. Benchmarking steps include:

[0023] a1) collimator calibration sub-step: by adjusting the azimuth and elevation posture and focal position of the collimator, ensure that the red light beam with a preset wavelength is vertically pointed to the lens of the collimator, and accurately record the pixel position of the optical axis point; a2) 45° reflector posture calibration sub-step: by using the combination of the collimator and the reflector, by accurately adjusting the position and posture of the 45° reflector, ensure that the center of the reflected light spot coincides with the reference coordinate of the axis point of the collimator;

[0024] B. Optical flat plate component gluing steps: glue the substrate and the light shielding tube, the substrate and the glass sleeve, and the porous plate and the glass sleeve in sequence by dispensing, and use a plastic fastening ring and a rubber band to assist in curing;

[0025] C. The steps of installing and gluing the transceiver lens array and the optical fiber glass tube end include:

[0026] c1) accurately placing the lens on the substrate and performing two-dimensional translation adjustment by non-mechanical means;

[0027] c2) Apply UV glue evenly around the outer periphery of the optical fiber glass tube end, gently insert it into the small hole of the porous plate, and make fine adjustments to ensure that the light spot observed on the observation device is a minimum focused uniform circle with no overexposure in brightness;

[0028] C3) Turn on the UV lamp to glue and solidify the lens and the optical fiber glass tube end, and record the pixel position of the center of mass of the light spot at this time as a reference for subsequent verification;

[0029] c4) gluing other receiving lenses and transmitting channels in sequence to ensure that the centroid position of the light spot of each channel coincides with the reference;

[0030] D. Additional glue spot bonding step: Additional glue spot bonding is performed on the outer edges of each circular plate.

[0031] Compared with the prior art, the technical effects of the present invention are as follows:

[0032] The present invention realizes a laser radar array transceiver device without mechanical components. No mechanical components are required, and all optical components are assembled and adjusted by gluing. According to the array design plan, a process flow is formulated for assembly and calibration, in which light pipes and CCD are used in each link to judge the assembly and calibration quality, and the accuracy can reach the micro-arc level. The assembly and calibration process is simple, the assembly and adjustment method is simple, and the operability is strong. The device of the present invention has the characteristics of small size, light weight, compactness, high integration, vibration resistance, and no stress caused by temperature difference changes. In the traditional mechanical assembly and adjustment method, due to the different thermal expansion coefficients between mechanical components and optics, the optical axis of the array optics will change in the airborne high and low temperature operating environment, affecting the working performance of the laser radar or laser communication system. The optical components of the device of the present invention are selected using the same glass material and have the same thermal expansion coefficient, which can ensure the stability of the overall optical axis parallelism of the system. Since the mechanical components are abandoned, the assembly of optical components is glued by uniform ultraviolet glue, the volume and weight are compressed and reduced, and it can be widely used in laser communication and ranging laser radar systems of various ground-based platforms and airborne platforms.

[0033] Through the design without mechanical components, the present invention effectively reduces the complex mechanical structure and moving parts in the traditional laser radar device, thereby reducing the manufacturing and maintenance costs, while improving the stability and reliability of the system. The gluing and fixing method ensures the precise alignment and firm connection between the various optical devices, avoiding the deviation and looseness caused by mechanical vibration or long-term use. The glass tube of the transmitting optical fiber and the transceiver porous plate are fixed by gluing after being adjusted to the appropriate three-dimensional posture, ensuring the precise alignment of the optical path and improving the measurement accuracy and performance of the laser radar. The focal length of the receiving lens is accurately determined by the glass sleeve, which further ensures the stability and consistency of the optical path. The one-transmit-N-receive transceiver array design effectively improves the data acquisition efficiency and coverage of the laser radar, and is suitable for a variety of application scenarios. The outer edge spacing between the laser receiving channels is less than 1mm, which realizes the high-density integration of optical devices and further improves the compactness and performance of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a schematic diagram of the structure of an embodiment of a laser radar array transceiver device without mechanical components of the present invention.

[0035] Figure 2 This is a schematic diagram of the assembly, calibration and testing of the laser radar array transceiver device without mechanical components of the present invention. DETAILED DESCRIPTION

[0036] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments, but this should not be used to limit the protection scope of the present invention.

[0037] See also Figure 1 , Figure 1 This is a schematic diagram of the structure of an embodiment of a laser radar array transceiver device without mechanical components of the present invention. As shown in the figure, a laser radar array transceiver device completely abandons mechanical components and instead uses gluing to fix all optical devices. The device consists of the following key parts:

[0038] Laser emission channel 1 is responsible for emitting laser signals.

[0039] N laser receiving channels 2 surround the laser emitting channel 1 and are responsible for receiving the reflected laser signal, forming a one-transmit-N-receive array. In this embodiment, the outer edge spacing of each laser receiving channel 2 is less than 1 mm.

[0040] The transmitting and receiving lens substrate 3 is used to support and accurately position the transmitting and receiving lenses.

[0041] The transceiver optical fiber porous plate 4 provides a fixed channel for the optical fiber to ensure stable transmission of the optical signal.

[0042] The glass sleeve 5 cooperates with the transceiver lens substrate 3 and the transceiver optical fiber porous plate 4 to determine the focal length of the lens.

[0043] The transmitting column 6 connects the transmitting optical fiber plate 7 and the transmitting and receiving optical fiber porous plate 4 to ensure the stability of the transmitting channel.

[0044] In order to ensure the high precision and stability of the device, the installation and judgment need to follow the following process sequence, including three steps: benchmark determination, gluing of optical plate components and installation and gluing of optical fiber tube ends. The following is a technical description of each step.

[0045] S1. Benchmark determination: including benchmark calibration of collimator and 45° reflector.

[0046] The calibration of the collimator is mainly carried out in the following steps:

[0047] a) The red light beam with a wavelength of 632nm is directed to the optical tube lens. The light beam passes through a cardboard with a small hole. The reflected light spot returned by the lens is observed. The azimuth and pitch attitude of the optical tube are adjusted so that multiple light spots overlap and return to the small hole, indicating that the red light beam is vertically directed to the optical tube lens;

[0048] b) Adjust the position of the end face of the emitting optical fiber at the focal plane of the optical tube so that the red light beam hits the end face of the optical fiber;

[0049] c) The self-collimating transmitting fiber flange of the optical tube focal plane is connected to a 1550nm or 1064nm laser, the laser is reflected, a reflection angle cone is placed in front of the optical tube lens, and the optical axis point pixel position is observed and recorded on the self-collimating camera of the optical tube focal plane;

[0050] d) Keep the laser emission in the working band unchanged, replace the angle cone in front of the optical tube lens with a reflector, adjust the reflector posture so that the focused light appears on the optical axis point; then adjust the front and rear positions of the autocollimator, and observe the changes in the size, shape and circular symmetry of the spot on the focal plane camera during the process of defocusing-focusing-defocusing. The focal plane spot is in the focused state when it is the smallest and most symmetrical.

[0051] For the attitude calibration of the 45° reflector, the following steps are mainly followed:

[0052] a) Place the 45° climbing mirror and the reflector placed flat on the optical platform, so that the center height of the 45° reflector is consistent with the center height of the collimator and they are symmetrical.

[0053] b) Reflect the red light at the focal plane of the collimator, adjust the position and posture of the 45° reflector and the flat reflector, so that the 45° reflector is located in the center of the large area red light spot after beam expansion emitted by the collimator and the flat reflector is in the center of the elliptical light spot reflected downward by the 45° reflector;

[0054] c) Remove the cardboard with the small hole, and place it above the lying reflector and in front of the parallel light tube lens respectively, observe the position of the light passing through the paper hole and the reflected light in turn, adjust the posture of the 45° reflector to make the reflected light return through the paper hole along the original path; finally, observe the position of the return light spot on the light tube self-collimation CCD camera, and fine-tune the posture of the 45° reflector to make the center of the light spot appear on the reference coordinate of the axis point of the light tube.

[0055] d) Switch the backlight of the light tube to the working band and observe the change of the light spot position. If the light spot position changes, fine-tune the posture of the 45° reflector again so that the center of the light spot of the working band appears on the reference coordinate of the axis point of the light tube. At this point, the posture calibration of the 45° reflector is completed.

[0056] S2. Optical flat panel components bonding:

[0057] a) Firstly, glue the substrate and the light shielding tube together;

[0058] b) Then glue the substrate and the glass sleeve together with glue dots, distribute the glue dots at multiple points, and control the glue amount to prevent it from overflowing. After kneading, wipe the outer edge with alcohol 3-4 times to remove any possible overflowed glue, and then close it with a plastic fastening ring and tighten it with a rubber band to wait for it to solidify;

[0059] c) Finally, glue the porous plate and glass sleeve together using the same method and precautions as in the previous step.

[0060] S3. Installation and gluing of the transceiver lens array and the optical fiber glass tube end:

[0061] a) Place the edge of the glued substrate / sleeve / porous plate combination vertically on the perforated support platform. The circular hole size of the support platform is slightly smaller than the outer diameter of the sleeve. Place the receiving lens on the substrate according to the position of the pins, and ensure that the center of the lens is vertically aligned with the small hole of the porous plate below. At this time, no glue dispensing is performed. The lens can be adjusted in two-dimensional translation on the substrate by mechanical tentacles.

[0062] b) The installation and gluing of the fiber optic glass tube end is carried out by inserting the fiber optic glass tube end into the corresponding small hole on the perforated plate below the receiving lens and moving it up and down. Apply UV glue evenly on the outer periphery of the glass tube end in advance, and after gently inserting the fiber optic glass tube end into the small hole, first observe the light spot on the CCD at the rear focal plane of the collimator. Adjust the optical adjustment platform where the entire optical array is located so that the center of mass of the light spot coincides with the optical axis point of the collimator positioned by the angle cone.

[0063] c) Fine-tune the longitudinal depth and tilt of the fiber optic glass tube end and the position of the lens on the substrate, so that the light spot on the CCD is a minimum focused uniform circular light spot with no overexposure. At this time, the fiber optic light source and the lens on the substrate are in focus. After dispensing glue on the edge of the lens on the substrate, turn on the UV lamp to glue and cure the upper lens on the substrate and the lower fiber optic glass tube end, and observe the position change of the light spot on the CCD during the curing process. Record the final pixel position of the centroid of the light spot, and use this position as a reference for subsequent installation and verification of other receiving lenses and transmitting lenses.

[0064] d) Adhere to the previous step to glue the other receiving lenses in turn, and ensure that the centroid position of the light spot of each channel after gluing coincides with the reference pixel point position.

[0065] e) The installation and gluing of the emission channel is consistent with the steps bc above. The only difference is that the focal length of the emission lens in the optical array of one-transmit-multiple-receive is greater than the focal length of the receiving lens. Therefore, the glass tube end of the emission fiber is installed behind the porous plate, and the emission plate is connected to the central circular hole of the porous plate through an emission column. Before gluing, it is also necessary to fine-tune the longitudinal depth of the emission lens and the glass tube end of the emission fiber. Ensure that the light spot on the collimator focal plane camera is a minimum focused uniform circular light spot with no overexposure, and the position of the center of mass also coincides with the position of the reference reference pixel point mentioned above.

[0066] S4. Additional glue bonding: Additional glue bonding is performed on the outer edges of each circular plate contact to enhance the stability of the overall system surface contact.

[0067] The laser radar array transceiver device without mechanical components in this embodiment has an appearance close to a cylinder, and the system size is about 70mm long × Φ35mm, and the weight is about 200 grams, which is only the size of an adult's palm, and can be easily matched with various airborne beam expansion optical system interfaces. The present invention first designs the transmitting and receiving lens groups according to the system requirements, and designs the substrate, porous plate, transmitting bottom plate and shading sleeve for installation according to the geometric optical relationship. UV glue is used to glue the auxiliary components and optical elements. Since it is separated from the traditional mechanical assembly and calibration, it is necessary to follow a specific order and adjustment method during the gluing installation and adjustment process, and refer to the step description of the specific implementation method. Since there are no mechanical components, the external spacing of each optical channel in the glued transceiver is only 1mm, which increases the optical aperture duty cycle, reduces the volume and reduces the system weight. Each device uses the same glass material and has a consistent thermal expansion coefficient, which greatly reduces the impact of temperature changes. Because it is small and light, it is very suitable for the beam expansion application scenario of the airborne laser system.

Claims

1. A laser radar array transceiver device without mechanical components, characterized in that: include: A laser emission channel (1), comprising an emission optical fiber plate (7), an emission column (6), and an emission lens on a transceiver lens substrate (3), wherein the emission optical fiber plate (7) is fixed to the emission column (6) by gluing, the other end of the emission column (6) is fixed to the transceiver optical fiber porous plate (4) by gluing, the emission lens is glued and fixed to the center of the transceiver lens substrate (3), and the focal length of the emission lens is determined by the sum of the lengths of the glass sleeve (5) and the emission column (6); N laser receiving channels (2), each laser receiving channel (2) comprising a receiving lens arranged on the transceiver lens substrate (3), the focal length of the receiving lens being determined by a glass sleeve (5); A transmitting and receiving lens substrate (3), used for supporting a transmitting lens and a receiving lens; The transmitting and receiving optical fiber porous plate (4) is used to fix the transmitting column (6) and the optical fiber glass tube of the receiving channel; A glass sleeve (5), one end of which is fixed to the transmitting and receiving optical fiber porous plate (4) by gluing, and the other end of which is fixed to the transmitting and receiving lens substrate (3) by gluing, so as to determine the focal length of the transmitting lens and the receiving lens; The laser emitting channel (1) is arranged at the center of the transceiver optical fiber porous plate (4), and N laser receiving channels (2) are arranged in a ring shape around the laser emitting channel (1), forming a one-transmit-N-receive transceiver array, where N is an integer greater than or equal to 1.

2. The laser radar array transceiver device without mechanical components according to claim 1, characterized in that: After the glass tube of the transmitting optical fiber and the transmitting and receiving porous plate (4) are adjusted to a suitable three-dimensional posture, they are fixed by gluing to ensure the precise alignment of the optical path.

3. The laser radar array transceiver device without mechanical components according to claim 1, characterized in that: The receiving lens is glued to the center of the transceiver lens substrate (3), and the focal length of the receiving lens, that is, the distance between the transceiver lens substrate and the transceiver porous plate, is determined by the glass sleeve.

4. The laser radar array transceiver device without mechanical components according to claim 1, characterized in that: The outer edge spacing between the laser receiving channels (2) is less than 1 mm.

5. The laser radar array transceiver device without mechanical components according to any one of claims 1 to 4, characterized in that: It also includes a fine-tuning mechanism for fine-tuning the three-dimensional posture of each optical device. The fine-tuning mechanism is used to ensure the alignment accuracy of each optical device before gluing and is removed during the gluing process.

6. The laser radar array transceiver device without mechanical components according to any one of claims 1 to 4, characterized in that: The bonding method uses ultraviolet glue or other suitable optical adhesives, and during the bonding process, a suitable auxiliary fixing device is used to ensure that the position of the optical device is stable until the adhesive is cured.

7. A calibration and determination process of a laser radar array transceiver device without mechanical components, characterized in that: The following steps are involved: A. Benchmarking steps include: a1) collimator calibration sub-step: by adjusting the azimuth and elevation posture and focal position of the collimator, ensure that the red light beam with a preset wavelength is vertically pointed to the lens of the collimator, and accurately record the pixel position of the optical axis point; a2) 45° reflector posture calibration sub-step: by using the combination of the collimator and the reflector, by accurately adjusting the position and posture of the 45° reflector, ensure that the center of the reflected light spot coincides with the reference coordinate of the axis point of the collimator; B. Optical flat plate component gluing steps: glue the substrate and the light shielding tube, the substrate and the glass sleeve, and the porous plate and the glass sleeve in sequence by dispensing, and use a plastic fastening ring and a rubber band to assist in curing; C. The steps of installing and gluing the transceiver lens array and the optical fiber glass tube end include: c1) accurately placing the lens on the substrate and performing two-dimensional translation adjustment by non-mechanical means; c2) Apply UV glue evenly around the outer periphery of the optical fiber glass tube end, gently insert it into the small hole of the porous plate, and make fine adjustments to ensure that the light spot observed on the observation device is a minimum focused uniform circle with no overexposure in brightness; C3) Turn on the UV lamp to glue and solidify the lens and the optical fiber glass tube end, and record the pixel position of the center of mass of the light spot at this time as a reference for subsequent verification; c4) gluing other receiving lenses and transmitting channels in sequence to ensure that the centroid position of the light spot of each channel coincides with the reference; D. Additional glue spot bonding step: Additional glue spot bonding is performed on the outer edges of each circular plate.

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