Laser radar array transceiver without mechanical components and its alignment and determination process

Abstract

A kind of mechanical componentless laser radar array transceiver, including by laser emission channel, echo receiving channel and glass sleeve etc.The emission channel is composed of emission lens, substrate, emission bottom plate and emission optical fiber glass end, and the echo receiving channel is composed of receiving lens group, substrate, receiving bottom plate and receiving optical fiber glass end.The application relates to the fixed combination operation of the optical devices of emission and receiving channel, is made by using gluing, does not use mechanical component completely, has the characteristics such as small volume, light weight, compactness, high integration, anti-vibration, not affected by stress caused by temperature difference change, etc., is suitable for various airborne and airless platform laser communication, radar and laser countermeasure system.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of space laser engineering applications, and relates to a laser radar array transceiver device without mechanical components and its assembly, calibration and determination process. Without the intervention of mechanical components, all optical elements are assembled and adjusted by gluing, and have the characteristics of small size, light weight, compactness, high integration, anti-vibration, and no stress influence caused by temperature difference changes. BACKGROUND

[0002] Laser radar array transmission and reception technology has significant advantages in space laser applications. Array transmission technology improves the detection efficiency and coverage of laser radar by simultaneously working multiple transmitting units. Array reception technology improves the speed and accuracy of signal processing by parallel working multiple receiving modules. For example, in synthetic aperture laser radar, array balanced detectors can be used for coherent transmission and reception, which greatly expands the imaging field of view and improves the imaging resolution. This technology not only improves the sensitivity of the system, but also maintains high data acquisition speed and accuracy in complex environments. Laser radar 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 transmission and reception systems usually use mechanical fixation for installation and debugging, 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 optical axis and affect 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 frequency relative drift is 4×10 -10 . The thermal expansion coefficient of quartz material is lower, only 5×10 -7 / K, so its deformation is smaller under the same temperature change. This material characteristic determines that the deformation difference between optical glass and mechanical components will significantly affect the stability of the optical axis in an environment with large temperature changes. The consistency of multiple optical axes is difficult to guarantee when the environmental temperature changes, causing the wavefront correction reference and tracking zero to shift, affecting the establishment of the communication link.

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

[0005] In the patent of Feng Liang et al., a laser transmitter, laser receiver and laser radar scheme is proposed (see patent application number CN202322845855.1), a structure design of laser transmitter and laser receiver is proposed, by configuring the thermal expansion coefficient of the second fixing part, it is ensured that the laser transmitter and the laser receiver can still be aligned to the same target object when the working environment temperature changes, thereby improving the stability and precision of the laser radar in different working environments. In addition, some researchers propose to use a precision temperature control system to strictly control the internal temperature fluctuation of the system, reduce the influence of temperature change on performance, and establish a multi-mirror error transfer model, and the optical axis consistency of the system is analyzed in depth and verified by experiment.

[0006] Although there have been attempts to adjust the thermal expansion coefficient of the fixing part, use a precision temperature control system, and establish a multi-mirror error transfer model to alleviate the influence of temperature change on the optical axis consistency, these methods are mostly passive responses, and there are limitations, and there is an urgent need for more innovative and efficient technical means to overcome these shortcomings. SUMMARY

[0007] In order to reduce the deformation of the mechanical components used to fasten the transmitting and receiving optical arrays in the spatial laser engineering system with temperature changes and the influence of mechanical vibration on the optical system, the present application proposes a mechanical component-free laser radar array transceiver device and its installation and determination process, which completely eliminates the traditional mechanical components by using a gluing method to fix the optical devices, thereby realizing the miniaturization, lightweight, high compactness and high integration of the device. Not only improves the vibration resistance and adaptability to temperature changes of the system, but also significantly improves the aperture ratio of the optical aperture, enhances the receiving efficiency, and is particularly suitable for airborne and spaceborne platform laser communication, radar and laser countermeasure systems.

[0008] The technical scheme of the present application is as follows:

[0009] On the one hand, the present application provides a mechanical component-free laser radar array transceiver device, characterized in that it comprises:

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

[0011] N laser receiving channels (2), each of which comprises 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 transceiver lens substrate (3) for supporting the transmitting lens and the receiving lens;

[0013] a transceiver fiber multi-hole plate (4) for fixing the transmitting column (6) and the fiber glass tube of the receiving channel;

[0014] a glass sleeve (5) fixed by gluing at one end to the transceiver fiber multi-hole plate (4) and at the other end to the transceiver lens substrate (3), thereby determining the focal length of the transmitting lens and the receiving lens;

[0015] wherein the laser transmitting channel (1) is arranged at the center of the transceiver fiber multi-hole plate (4), and N laser receiving channels (2) are arranged in a ring around the laser transmitting channel (1), forming a transmitting-receiving array, and N is an integer greater than or equal to 1.

[0016] Further, the glass tube of the transmitting fiber is fixed by gluing after being adjusted to a suitable three-dimensional pose with the transceiver multi-hole plate (4), to ensure accurate alignment of the optical path.

[0017] Further, the receiving lens is glued at the center of the transceiver lens substrate (3), and the focal length of the receiving lens, i.e. the distance between the transceiver lens substrate and the transceiver multi-hole plate, is determined by the glass sleeve.

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

[0019] Further, it further comprises a fine adjustment mechanism for fine adjustment of the three-dimensional pose of each optical device, which is used to ensure the alignment accuracy of each optical device before gluing, and is removed during the gluing process.

[0020] Further, the gluing method uses ultraviolet glue or other suitable optical glue, and the position of the optical device is stabilized by appropriate auxiliary fixing devices during the gluing process until the glue is cured.

[0021] In another aspect, the present application also provides a calibration and determination process of a mechanical component-free laser radar array transceiver device, characterized in that it comprises the following steps:

[0022] A. Reference determination step, comprising:

[0023] a1) collimator calibration sub-step: by adjusting the azimuth and elevation attitude of the collimator and the focal plane position, ensure that the red light beam with a preset wavelength is perpendicular to the lens of the collimator, and accurately record the pixel position of the optical axis point; a2) 45° mirror attitude calibration sub-step: by adjusting the position and attitude of the 45° mirror, the center of the reflected light spot and the optical axis point reference coordinates of the collimator are ensured to coincide;

[0024] B. optical flat element gluing step: using dispensing method, sequentially glue the substrate and the light shielding cylinder, the substrate and the glass sleeve, and the multi-hole plate and the glass sleeve, and use plastic fastening ring and rubber band to assist curing;

[0025] C. transceiver lens array and optical fiber glass tube end installation gluing step, comprising:

[0026] c1) accurately place the lens on the substrate and adjust the two-dimensional translation by non-mechanical method;

[0027] c2) evenly apply ultraviolet glue on the periphery of the optical fiber glass tube end, gently send it into the small hole of the multi-hole plate, and adjust the focus to ensure that the observed light spot on the observation device is a small focused uniform circle with no overexposure of brightness;

[0028] C3) open the ultraviolet lamp to glue and cure the lens and the optical fiber glass tube end, and record the pixel position of the light spot centroid at this time as the reference for subsequent checking;

[0029] c4) sequentially glue the other receiving lenses and transmitting channels to ensure that the light spot centroid positions of the channels coincide with the reference;

[0030] D. additional dispensing and bonding step: additional dispensing and bonding are performed on the outer edges of the contact of each circular plate.

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

[0032] The application realizes a mechanical component-free laser radar array transceiver device, without the intervention of mechanical components, and all optical elements are assembled and adjusted by gluing. According to the array design scheme, a process flow is formulated for assembly and adjustment, and each link uses an optical pipe and a CCD for assembly and adjustment quality evaluation, and the precision can reach a micro-radian level. The assembly and adjustment process flow is simple, the assembly and adjustment mode is simple, and the operability is strong. The device has the characteristics of small size, light weight, compactness, high integration, vibration resistance, and no stress influence caused by temperature difference change. Due to the difference in thermal expansion coefficients between mechanical components and optics in the traditional mechanical assembly and adjustment mode, the optical axis of the array optics will change in the airborne high-low temperature operating environment, affecting the working performance of the laser radar or laser communication system. The optical components of the device are selected from the same glass material, have the same thermal expansion coefficient, and can ensure the stability of the overall optical axis parallelism of the system. Since the mechanical components are abandoned, the assembly of the optical elements is realized by uniform ultraviolet glue gluing, and the volume and weight are compressed and reduced, so the device can be widely applied to laser communication and ranging laser radar systems of various ground platforms and airborne platforms.

[0033] Through the mechanical component-free design, the application effectively reduces the complex mechanical structure and movable parts in the traditional laser radar device, thereby reducing the manufacturing and maintenance costs, and improving the stability and reliability of the system. The gluing fixing mode ensures the accurate alignment and stable connection between the optical devices, avoids the deviation and looseness caused by mechanical vibration or long-term use. The glass tube of the transmitting optical fiber is fixed by gluing after being adjusted to a suitable three-dimensional attitude together with the transceiving multi-hole plate, so as to ensure the accurate alignment of the optical path and improve 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 transceiving array design of one transmitting and N receiving effectively improves the data acquisition efficiency and coverage range of the laser radar, and is suitable for various application scenarios. The outer edge distance between the laser receiving channels is less than 1mm, realizing the high-density integration of the optical devices, and further improving the compactness and performance of the system. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 is a structural schematic diagram of an embodiment of the mechanical component-free laser radar array transceiver device of the application

[0035] Figure 2 is an assembly and adjustment test schematic diagram of the mechanical component-free laser radar array transceiver device of the application DETAILED DESCRIPTION

[0036] The technical solutions of the application will be further described below in combination with the drawings and embodiments, but the protection scope of the application should not be limited thereby.

[0037] Please refer to Figure 1 ,Figure 1 is a structural schematic diagram of a mechanical component-free laser radar array transceiver device embodiment of the present application. As shown in the figure, a laser radar array transceiver device completely discards mechanical components and instead uses gluing to fix all optical devices. The device is composed of the following key parts:

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

[0039] N laser receiving channels 2 surround the laser emission channel 1 and are responsible for receiving reflected laser signals; forming a one-transmitting and N-receiving transceiver array. The outer edge spacing of each laser receiving channel 2 in this embodiment is less than 1 mm.

[0040] A transceiver lens substrate 3 is used to support and precisely position the transmitting and receiving lenses.

[0041] A transceiver optical fiber multi-hole plate 4 provides a fixed channel for optical fibers, ensuring stable transmission of optical signals.

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

[0043] A transmitting column 6 connects the transmitting optical fiber plate 7 and the transceiver optical fiber multi-hole plate 4, ensuring the stability of the transmitting channel.

[0044] To ensure the high precision and stability of the device, the following process sequence needs to be followed for calibration and determination, including three links of reference determination, optical flat element gluing, and optical fiber tube end installation and gluing. The following will describe each link.

[0045] S1. Reference determination: including reference calibration of the collimator and the 45° reflector.

[0046] For the calibration of the collimator, the following steps are mainly followed:

[0047] a) A red light beam with a wavelength of 632 nm is directed at the collimator lens. The light beam passes through a paperboard with a small hole, and the reflected light spot returned by the lens is observed. The azimuth and pitch attitude of the collimator is adjusted so that multiple light spots coincide and return to the small hole, indicating that the red light beam is perpendicular to the collimator lens;

[0048] b) The position of the transmitting optical fiber end face at the collimator focal plane is adjusted again so that the red light beam hits the optical fiber end face;

[0049] c) The autocollimation transmitting optical fiber flange at the collimator focal plane is connected to a laser with a wavelength of 1550 nm or 1064 nm. The reflected laser is placed in front of the reflector cone, and the optical axis point pixel position is observed and recorded on the autocollimation camera at the collimator focal plane;

[0050] d) Keep the laser emission of working waveband unchanged, replace the corner cube in front of the light pipe lens with a mirror, adjust the posture of the mirror, so that the focused light appears on the optical axis point; then adjust the front and back positions of the collimator, observe the changes of the light spot size and shape and the circular symmetry on the focal plane camera from the defocus-focalization-defocus process, and take the minimum and most symmetrical focal plane light spot as the focalization state.

[0051] For the posture calibration of the 45° mirror, the following steps are mainly carried out:

[0052] a) Place the 45° climbing mirror and the parallel light pipe on the optical platform, so that the height of the center of the 45° mirror is consistent with the center height of the parallel light pipe and left-right symmetrical;

[0053] b) Adjust the positions and postures of the 45° mirror and the parallel light pipe, so that the 45° mirror is located in the center area of the large-area red light spot emitted by the parallel light pipe, and the lying mirror is located in the center area of the elliptical light spot reflected downward by the 45° mirror;

[0054] c) Remove the paper board with a small hole, and place it above the lying mirror and in front of the light pipe lens respectively, and observe the positions of the light passing through the paper hole and the reflected light in turn, adjust the posture of the 45° mirror, so that the reflected light returns to the original path through the paper hole; finally, observe the position of the reflected light spot on the self-collimating CCD camera of the light pipe, and slightly adjust the posture of the 45° mirror, so that the center of the light spot appears on the reference coordinates of the axis point of the light pipe.

[0055] d) Switch the reflected light of the light pipe to the working waveband, observe the change of the light spot position, if the light spot position changes, adjust the posture of the 45° mirror again, so that the center of the light spot of the working waveband appears on the reference coordinates of the axis point of the light pipe. Thus, the posture calibration of the 45° mirror is completed.

[0056] S2. Optical flat element gluing:

[0057] a) First, point the glue and glue the substrate and the light shielding cylinder;

[0058] b) Then, point the glue and glue the substrate and the glass sleeve, distribute the glue points, control the amount of glue to not overflow, rub it evenly, wipe the outer edge 3-4 times with alcohol to remove the possible overflow glue, and then use a plastic fastening ring to fold it and tighten it with a rubber band until it solidifies;

[0059] c) Finally, point the glue and glue the multi-hole plate and the glass sleeve in the same way as the previous step.

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

[0061] a) The edge of the glued substrate / sleeve / multi-hole plate combination is vertically supported on an open-hole support platform, the size of the circular hole of the support platform is slightly smaller than the outer diameter of the sleeve. The lens is placed on the substrate according to the position of the pin, ensuring that the center of the lens is vertically aligned with the small hole of the multi-hole plate below. At this time, the lens on the substrate can be adjusted in two-dimensional direction by mechanical tentacles.

[0062] b) The installation and gluing of the end of the optical fiber glass tube is carried out by inserting the end of the optical fiber glass tube into the corresponding small hole of the multi-hole plate below in an up-and-down manner. The outer periphery of the glass tube end is uniformly coated with UV glue in advance. After the end of the optical fiber glass tube is gently sent into the small hole, the light spot is first observed on the CCD behind the focal plane of the collimator. The optical adjustment platform on which the entire optical array is located is adjusted so that the centroid of the light spot coincides with the optical axis point of the collimator through the corner cube.

[0063] c) The longitudinal depth and inclined posture of the end of the optical fiber glass tube and the position of the lens on the substrate are fine-tuned so that the light spot on the CCD is a minimum focused uniform circular spot with no overexposure of brightness. At this time, the optical fiber light source and the lens on the substrate are in a focused state. After the edge of the lens on the substrate is glued, the UV lamp is turned on to glue and cure the lens on the substrate above and the end of the optical fiber glass tube below, respectively. The position change of the light spot on the CCD during the curing process is observed, and the final pixel position of the centroid of the light spot is recorded. This position is used as a reference for subsequent installation and verification of other receiving lenses and transmitting lenses.

[0064] d) The other receiving lenses are glued in the same way as in the previous step, ensuring that the centroid positions of the light spots of each channel after gluing coincide with the pixel position of the reference.

[0065] e) The installation and gluing of the transmitting channel are consistent with steps b-c above, the only difference being that the focal length of the transmitting lens in the one-transmitting-multiple-receiving optical array is greater than that of the receiving lens. Therefore, the end of the transmitting optical fiber is installed behind the multi-hole plate, and the transmitting plate is connected to the central circular hole of the multi-hole plate through a transmitting column. Before gluing, the longitudinal depth of the transmitting lens and the end of the transmitting optical fiber glass tube also needs to be fine-tuned. Ensure that the light spot on the camera behind the focal plane of the collimator is a minimum focused uniform circular spot with no overexposure of brightness, and the centroid position also coincides with the pixel position of the reference.

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

[0067] The mechanical component-free laser radar array transceiver device of the embodiment has a cylindrical appearance, the system size is about 70mm long*35mm in diameter, the weight is about 200g, and only the size of an adult's palm, which can be very light to match various airborne beam expansion optical system interfaces. The invention first designs the transmitting and receiving lens groups according to the system requirements, designs the substrate, multi-hole plate, transmitting bottom plate and light shielding sleeve for installation according to the geometric optical relationship, and uses ultraviolet glue to glue the auxiliary components and optical elements. Since it deviates from the traditional mechanical type, the gluing installation and adjustment process needs to be carried out in a specific order and adjustment method, and the step description of the specific embodiment is referred to. Since there is no mechanical component, the external spacing of each optical channel in the glued transceiver device is only 1mm, which improves the optical aperture duty cycle, reduces the volume and also reduces the system weight. The same glass material is used for each device, and the thermal expansion coefficient is consistent, which greatly reduces the influence of temperature changes. Due to its small size and light weight, it is very suitable for the beam expansion application scene of airborne laser systems.

Claims

1. A laser radar array transceiver device without mechanical components, characterized in that, include: The laser emission channel (1) includes an emission fiber plate (7), an emission column (6), and an emission lens on a transceiver lens substrate (3). The emission fiber plate (7) is glued to the emission column (6), and the other end of the emission column (6) is glued to the transceiver fiber perforated plate (4). The emission lens is glued 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) includes a receiving lens disposed on the transceiver lens substrate (3), the focal length of the receiving lens being determined by the glass sleeve (5); Transceiver lens substrate (3) is used to support the transmitting lens and the receiving lens; Transceiver fiber optic multi-hole plate (4) is used to fix the transmitting column (6) and the optical fiber glass tube of the receiving channel; The glass sleeve (5) is fixed at one end to the transceiver fiber perforated plate (4) by gluing, and at the other end to the transceiver lens substrate (3) by gluing, thereby determining the focal length of the transmitting lens and the receiving lens; The laser emitting channel (1) is located at the center of the transceiver fiber perforated plate (4), and N laser receiving channels (2) are arranged in a ring around the laser emitting channel (1) to form a transceiver array with one transmitter and N receivers, 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 transceiver porous plate (4) are adjusted to a suitable three-dimensional posture, they are glued together 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 bonded to the center of the transceiver lens substrate (3), and the focal length of the receiving lens, i.e. the distance between the transceiver lens substrate and the transceiver perforated 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 distance between the outer edges of 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 1-4, characterized in that, It also includes a fine-tuning mechanism for fine-tuning the three-dimensional orientation of each optical component, which is used to ensure the alignment accuracy of each optical component 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 1-4, characterized in that, The bonding method uses ultraviolet adhesive or other suitable optical adhesives, and during the bonding process, appropriate auxiliary fixing devices are used to ensure the stability of the optical components until the adhesive cures.

7. A calibration and evaluation process for a laser radar array transceiver device without mechanical components, characterized in that, Includes the following steps: A. The benchmark determination steps include: a1) Collimator calibration steps: By adjusting the azimuth, pitch, attitude, and focal plane position of the collimator, ensure that the red light beam with a preset wavelength is perpendicular to the collimator lens, and accurately record the pixel position of the optical axis point; a2) 45° reflector attitude calibration steps: Using the combination of collimator and reflector, by accurately adjusting the position and attitude of the 45° reflector, ensure that the center of the reflected light spot coincides with the reference coordinates of the optical tube's axis point; B. Optical flat panel component bonding steps: Using a dispensing method, the substrate is bonded to the light shielding tube, the substrate to the glass sleeve, and the perforated plate to the glass sleeve in sequence, and plastic fastening rings and rubber bands are used to assist in curing. C. The bonding and installation steps for the transceiver lens array and the fiber optic glass tube end include: c1) The lens is precisely placed on the substrate and adjusted in two dimensions by non-mechanical means; c2) Apply UV adhesive evenly to the outer periphery of the fiber optic 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. C3) Turn on the ultraviolet lamp to bond and cure the lens and the end of the fiber optic glass tube, and record the pixel position of the centroid of the light spot at this time as the benchmark for subsequent verification. c4) Sequentially cement the other receiving lenses and transmitting channels to ensure that the centroid of the light spot in each channel coincides with the reference. D. Additional adhesive bonding step: Apply additional adhesive to the outer edges where the circular plates meet.

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