Vehicle-mounted LBS projection ray machine and optical coupling method thereof

Abstract

The invention discloses a vehicle-mounted LBS projection ray machine and an optical coupling method thereof, and relates to the technical field of vehicle-mounted projection. The projection ray machine comprises a bottom shell, a PCBA-L, a support, a shell, a base, a laser, a collimating lens group, a light combination prism group, a dust cover, a PCBA-S and an MEMS scanning imaging system, the collimating lens group adopts a multi-piece adjustable doublet lens structure, the light combination prism group adopts a light splitting and light combination integrated design, and the dust cover is provided with double-layer protection and a special coating film. The optical coupling method comprises the steps of cleaning the base and fixing the laser, initially installing the optical component, accurately calibrating the collimating lens group, integrating the light source component and coupling the whole machine, detecting light spot parameters in real time through the light beam quality analyzer, and realizing high-precision optical adaptation by combining two schemes of distributed collimating coupling and simultaneous coupling. According to the invention, laser speckles are eliminated from the source, the color rendition stability is improved, the coupling precision is high, different production scenes are adapted, and the vehicle-mounted projection visual experience is effectively optimized.

Description

Technical Field

[0001] This invention relates to the field of vehicle-mounted projection technology, and in particular to a vehicle-mounted LBS projection optical engine and its optical coupling method. Background Technology

[0002] With the rapid development of intelligent connected vehicles, in-vehicle display systems have been upgraded from traditional instrument panels to multi-scenario interactive projection. Laser projection optical engines have become the core technology direction in the field of in-vehicle displays due to their advantages such as high brightness, wide color gamut, and long lifespan.

[0003] Compared to traditional mercury lamps and LED light sources, red, green, and blue laser light sources can provide a wider color coverage and higher light energy density, theoretically achieving imaging effects close to the limits of human vision. Therefore, they are widely used in scenarios such as in-vehicle head-up displays and rear-seat entertainment projections.

[0004] However, the combination of the high coherence of lasers and the complex working conditions in vehicles presents two major technical bottlenecks that need to be overcome for existing in-vehicle laser projection systems, which severely restrict their imaging quality and user experience.

[0005] First, laser speckle is an interference phenomenon caused by the combined effect of the spatial and temporal coherence of the laser. After being emitted from the laser, the laser beam naturally diffuses into an elliptical beam. During propagation, it is prone to scattering due to uneven beam spread angle. When these phase-consistent scattered lights are superimposed on the projection surface, they form a randomly distributed pattern of bright and dark particles, i.e., speckle. To solve this problem, existing technologies mainly adopt passive suppression schemes, such as adding a random phase modulator in the optical path to destroy the laser coherence, or using optical diffusers such as frosted glass to scatter the beam. However, these schemes have high phase modulator costs and are greatly affected by vehicle temperature fluctuations, which can easily lead to modulation accuracy drift. Although optical diffusers can reduce speckle contrast, they significantly increase light energy loss, resulting in a decrease in projection brightness and the introduction of image blurring. Some improvement schemes attempt to reduce the laser spread angle through a single-lens collimation structure, but the collimation capability of a single lens is limited and cannot achieve precise adaptation to the different wavelength characteristics of the three-color laser. The consistency of the beam propagation direction is difficult to guarantee, and the speckle problem can only be alleviated but not eliminated at its root. The projected image still has obvious graininess, blurred edge contours, and insufficient detail.

[0006] Secondly, there are issues with color reproduction distortion and poor stability. The accuracy of the three-color laser beam combining directly determines the color performance. The beam combining structure of existing vehicle projection systems mainly relies on dichroic filter groups or simple prism groups to achieve beam combining. Dichroic filter groups achieve wavelength selective transmission and reflection through multi-layer coating, but they have drawbacks such as complex installation and debugging and weak vibration resistance. Continuous vibration during vehicle operation can easily cause the filter light path to deviate, resulting in an imbalance in the mixing ratio of the three colors, leading to problems such as color cast and color fringing. At the same time, their beam combining efficiency is low, which can lead to excessive energy loss of some colors and harsh transitions between light and dark. Although the simple prism group has a relatively stable structure, it lacks a precise design to match the three-color laser. The angle error between the prism incident surface and the laser output direction is large, and the coating on the output surface is mostly only compatible with a single wavelength laser, which cannot achieve unbiased convergence of the three colors, and color separation or uneven mixing is likely to occur.

[0007] More significantly, existing coupling processes cannot meet the precision requirements of the light-combining structure. Traditional coupling methods often employ a single mode, either using step-by-step coupling but lacking a real-time detection mechanism, relying solely on visual observation for adjustment, which cannot guarantee the accuracy of the single-color laser transmission path, or using batch synchronous coupling but without a linkage adjustment mechanism, making it difficult to balance the light intensity and phase compatibility of the three-color lasers. This dual problem of structural design defects and insufficient process precision results in extremely poor color output stability of existing systems. Under conditions such as vehicle temperature changes and long-term vibration, color shift is particularly noticeable, with a large color deviation between the image and the original signal. Details in dark areas are masked due to uneven color mixing, and bright areas are prone to overexposure distortion, severely affecting the visual experience.

[0008] Therefore, this invention proposes an optical coupling method for a vehicle-mounted LBS projection optical engine. Summary of the Invention

[0009] One objective of this invention is to propose an in-vehicle LBS projection optical engine and its optical coupling method. This invention can fundamentally solve the problem of image degradation caused by laser speckle in existing in-vehicle laser projection systems through deep synergy between optical structure and coupling technology, while ensuring the stability and accuracy of color reproduction, and adapting to the long-term use requirements under complex in-vehicle conditions.

[0010] According to an embodiment of the present invention, an in-vehicle LBS projection optical engine includes a base, a laser, a collimating lens group, a beam combining prism group, a dust cover, a PCBA-S, a housing, and a MEMS scanning imaging system. The laser is fixed in the mounting groove of the base by dispensing adhesive, and the light emission direction of the laser is consistent with the optical axis of the subsequent optical components. The collimating lens group is located on the light-emitting side of the laser and is used to reduce the diffusion angle of the laser emitted by the laser. The collimating lens group is a multi-piece adjustable structure, with each lens arranged sequentially along the laser transmission direction and collinear with the optical axis. The collimation effect can be optimized by adjusting the relative position of each lens. The beam combining prism group is located on the light-emitting side of the collimating lens group. It adopts an integrated design of beam splitting and beam combining, and can receive red, green and blue lasers after being processed by the collimating lens group, and converge the three lasers into a single beam of polychromatic light without deflection. The beam combining prism group has a beam combining lens built in. The dust cover is installed on the outside of the light combining prism assembly. Its edge is sealed and fixed to the base by adhesive to prevent external impurities from entering the optical components. The dust cover has a light-transmitting port, which corresponds to the light-exiting path of the light combining prism assembly. The PCBA-S is electrically connected to the laser by welding, and is used to provide power support and control signals to the laser; The light source assembly, consisting of the base, laser, collimating lens group, beam combining prism group, dust cover and PCBA-S, is installed in the mounting slot inside the housing. The light-transmitting port of the dust cover is coaxially arranged with the corresponding light-transmitting port on the housing to ensure stable transmission of polychromatic light. The MEMS scanning imaging system is located on the light-emitting side of the light-transmitting port of the housing. The polychromatic light, after being converged by the light-combining prism group, is first focused and then incident on the MEMS scanning imaging system, which completes the final imaging.

[0011] Furthermore, each lens in the collimating lens group is a cemented doublet lens, and each cemented doublet lens is arranged sequentially along the laser transmission direction according to the focal length gradient. The lens closer to the laser has a smaller focal length, which is used to initially reduce the large-angle diffusion of the laser, while the lens farther away from the laser has a larger focal length, which is used to finely calibrate the transmission direction of the laser. The materials of each of the doublet lenses are selected according to the wavelength characteristics of red, green and blue lasers. The lens adapted to red light uses low dispersion optical glass, while the lenses adapted to green and blue light use high transmittance optical glass to reduce transmission loss and color difference of lasers of different wavelengths. The collimating lens group is provided with a lens fixing frame on the outside. The frame has positioning holes that are adapted to each lens. The inner wall of the positioning hole is provided with an elastic buffer ring, which can not only ensure the alignment of the lens optical axis, but also reduce the impact of vehicle vibration on the lens position.

[0012] Furthermore, the beam combining prism group includes three independent beam splitting prisms, each of which corresponds to the output path of the red, green, and blue lasers, and the three beam splitting prisms are arranged in a triangular pattern in the preset mounting area of ​​the base. The incident surface of each of the beam splitters is at a 45° angle to the output direction of the corresponding laser, and the incident surface is coated with an anti-reflection film of the corresponding wavelength to reduce the reflection loss of the laser at the incident surface. The light-emitting surfaces of the three beam splitters are on the same plane, and each light-emitting surface is coated with a three-color compatible light-combining film to ensure that the three-color lasers can converge into polychromatic light along the same optical axis after reflection and refraction. The base is provided with a positioning boss corresponding to the installation position of the beam splitter prism. The boss fits into the side of the prism and is fixed with adhesive to prevent the prism from shifting due to vehicle bumps.

[0013] Furthermore, the dust cover adopts a double-layer composite structure, with the inner layer being optical-grade transparent quartz glass and the outer layer being impact-resistant polycarbonate material. A heat dissipation gap of 0.5-1mm is reserved between the two layers, and micro heat dissipation fins are provided in the gap to assist the light-combining prism assembly in dissipating working heat. The light-transmitting opening of the dust cover is circular, and the inner edge of the light-transmitting opening of the dust cover is designed with rounded corners to avoid laser diffraction at the edge. In addition, the inner side of the light-transmitting opening of the dust cover is coated with a full-band anti-reflection film. The transmittance of the anti-reflection film to red, green and blue lasers is not less than 98%, and the film layer has high and low temperature resistance and anti-aging properties, making it suitable for long-term use in vehicles. The dust cover and the base are sealed with an annular sealing groove, which is filled with high-temperature resistant silicone. After the silicone cures, it forms a continuous sealing ring to prevent dust and moisture from entering the optical components.

[0014] Furthermore, it also includes the bottom shell, PCBA-L, and bracket; The bottom shell is made of aluminum alloy with an anodized layer on the surface, which has rust prevention and heat conduction properties. Multiple heat dissipation channels are opened inside the bottom shell, and cooling fans can be installed in the channels as needed. The bracket has a hollow structure and is integrally molded from engineering plastic. The two ends of the bracket are fixed to the upper surface of the bottom shell and the lower surface of the outer shell by bolts, respectively. The connection between the bracket and the outer shell is equipped with shock-absorbing pads to reduce the transmission of vehicle vibration to the optical components. PCBA-L is a multi-layer circuit board fixed on a circuit board bracket inside the bottom shell. PCBA-L and PCBA-S are connected by shielded wires. PCBA-L integrates a power management module, a signal processing module, and a communication module. The power management module provides a stable voltage for the entire projection optical engine. The signal processing module optimizes the control signals of the MEMS scanning imaging system. The communication module realizes bidirectional data transmission with the vehicle central control system. The bottom shell is provided with a waterproof strip along its edge, and a dustproof mesh is provided at the joint between the bottom shell and the outer shell, further enhancing the overall dustproof and waterproof capabilities of the machine.

[0015] An optical coupling method for a vehicle-mounted LBS projection optical engine includes the following steps: S1. Clean the surface of the base and the mounting groove. First, wipe the surface with anhydrous ethanol to remove oil stains, and then blow away the tiny impurities in the mounting groove with a high-pressure air gun to ensure that there are no foreign objects on the mounting surface. After evenly applying adhesive to the bottom of the laser, slowly press it into the mounting groove of the base. Use an optical alignment fixture to calibrate the laser's light output direction so that the laser's optical axis is aligned with the preset optical reference axis on the base. After calibration, apply adhesive evenly to the gap between the laser and the mounting groove, and let it stand until the adhesive cures to complete the fixation of the laser. S2. Using a multi-axis clamping fixture, place each lens of the collimating lens group in its designed position on the laser's output side. Ensure that the optical axis of each lens is initially aligned with the optical axis of the laser by using the fixture's positioning reference. Place the beam combining prism group on the prism positioning platform of the base and adjust the prism's orientation so that the prism's incident surface corresponds to the output side of the collimating lens group. Depending on the actual assembly accuracy requirements, pre-fix the collimating lens group by applying adhesive to the edge of the fixed frame and the side of the beam combining prism group to prevent the components from shifting during subsequent adjustments. S3. Secure the assembled components from step S2 horizontally onto the high-precision fixed base, ensuring no shaking during adjustment. Power on the components to allow the laser to emit laser light stably. Use a beam quality analyzer to measure the beam pattern at two different close-range positions in front of the beam combining prism assembly's output port. Calculate and determine the divergence angle of the light based on the differences in size and shape of the beam at the two positions. Adjust the fine-tuning knob of the clamping fixture to change the front-to-back position and relative spacing of each lens in the collimating lens assembly. Simultaneously, use a vacuum adsorption fixture to assist in fixing the lenses. Continuously adjust and repeatedly test the beam until the divergence angle meets the system's preset collimation requirements. Then, apply adhesive to the gaps between each lens and the fixed frame and allow it to cure to complete the fixing of the collimating lens assembly. S4. Assemble the optically coupled components from step S3 with the dust cover, ensuring that the light-passing port of the dust cover is precisely aligned with the light-emitting path of the light-combining prism group to ensure unobstructed transmission of polychromatic light. Fill the sealing groove between the dust cover and the base with sealant, press the dust cover to ensure that the sealant fully adheres to the sealing groove, and let it stand until the sealant cures to achieve a sealed and fixed connection between the dust cover and the base. Connect the assembled components to the PCBA-S using a reflow soldering process. After soldering, use a multimeter to test the circuit continuity to ensure that there are no open circuits or short circuits in the electrical signal between the PCBA-S and the laser, thus forming a complete light source component. S5. Using a vacuum clamping fixture, the light source assembly is horizontally placed into the housing mounting slot. The position of the light source assembly inside the housing is adjusted by using a laser alignment fixture to align the light passage of the dust cover with the light passage of the housing and keep them coaxial. Using a beam quality analyzer, the light source assembly is gradually moved near the theoretical optimal convergence position to observe and record the brightness, size, and uniformity of the light spot at different positions until the smallest and brightest light spot is observed. Adhesive is evenly applied to the gap between the light source assembly and the housing mounting slot and left to stand until the adhesive is completely cured to complete the fixation of the light source assembly, thereby achieving the optical coupling of the entire machine.

[0016] Furthermore, in step S, the collimation method of the collimating lens group can be selected as distributed collimation coupling or simultaneous coupling. The specific operation process of distributed collimation coupling is as follows: First, light up the red laser separately, and use a beam quality analyzer to detect the divergence angle of the red light spot after passing through the collimating lens group. Adjust the position of the lens corresponding to the red light until the divergence angle meets the standard. Then, turn on the green laser separately and repeat the above adjustment process; Finally, the blue laser is lit separately, and the blue lens is adjusted to ensure that the divergence angles of the three lasers all meet the requirements. The specific operation process for simultaneous coupling is as follows: Simultaneously illuminate red, green, and blue lasers, use a multi-channel beam quality analyzer to simultaneously detect the three-color beam spots, and use a linkage fine-tuning fixture to simultaneously adjust multiple lenses until the divergence angles of the three-color lasers all meet the system requirements. The distributed collimation coupling is suitable for small-batch, high-precision assembly scenarios, while the coupling is suitable for large-batch production scenarios. The appropriate coupling method can be selected according to actual production needs.

[0017] Furthermore, in step S1, the adhesive coated on the bottom of the laser is a conductive and thermally conductive adhesive. This conductive and thermally conductive adhesive has both good electrical conductivity and a high thermal conductivity coefficient. After curing, the conductive and thermally conductive adhesive has a certain elasticity, which can alleviate the thermal stress during laser operation. The adhesive is fixed by dispensing with UV-curing adhesive. During the dispensing process, the amount of adhesive is precisely controlled by the dispensing controller to ensure uniform adhesive layer thickness. The adhesive is cured by UV irradiation, and the irradiation time is adjusted according to the characteristics of the adhesive. After curing, the deviation between the laser optical axis and the base reference axis is detected by optical inspection fixture. If the deviation exceeds the tolerance, the adhesive can be softened by heating the fixture, and the laser position can be recalibrated until the deviation meets the requirements.

[0018] Furthermore, in step S, the adsorption head of the vacuum adsorption fixture is made of soft silicone. The shape of the adsorption head is adapted to the outer contour of the lens to avoid scratching the lens surface during adsorption. The adsorption pressure is monitored in real time by a pressure sensor and kept in a constant range of 0.02-0.05MPa. When adjusting the lens position, a piezoelectric ceramic driven fine-tuning fixture is used, and the adjustment accuracy can reach the micron level. After each adjustment, the adjustment is paused for 5-10 seconds until the detection data of the beam quality analyzer is stable before judging whether the divergence angle meets the standard. After the collimating lens group is fixed, a stability test is required. The component is powered on and works continuously for 1 hour. During this period, the beam divergence angle is checked every 15 minutes to confirm that the lens has not shifted due to the curing and shrinkage of the glue, ensuring the long-term stability of the collimation effect.

[0019] Furthermore, in step S5, when adjusting the coaxiality of the light-transmitting port of the dust cover and the light-transmitting port of the outer shell, a high-precision laser alignment instrument is used for auxiliary detection. The reference laser wavelength emitted by the alignment instrument is consistent with the laser wavelength of the projection optical engine. The detection probes of the alignment instrument are respectively set on the inner side of the light-transmitting port of the dust cover and the outer side of the light-transmitting port of the outer shell. By measuring the deviation of the reference laser signals received by the two probes, it is determined whether the centers of the two light-transmitting ports coincide. The position of the light source component is gradually adjusted until the signal deviation is less than the preset threshold, thus completing the coaxiality adjustment. During the light spot observation process, the theoretical maximum value is first determined according to the optical design parameters. Within the range of the optimal convergence position, move the beam quality analyzer along a zigzag path, pausing for 3-5 seconds after each movement to allow the data to stabilize. Record the area, brightness uniformity, and center offset of the light spot. By comparing all recorded data, select the position with the smallest light spot area, highest brightness, and best uniformity as the optimal coupling position. After the light source components are fixed, the coaxiality of the two light ports and the state of the light spot need to be checked again to confirm that there is no deviation caused by the shrinkage of the adhesive during curing. If there is a deviation, the cause of the deviation needs to be analyzed and corrective measures need to be taken to ensure that the coupling accuracy of the whole machine meets the requirements.

[0020] The beneficial effects of this invention are: 1. This invention fundamentally solves the speckle problem of laser projection through synergistic innovation in optical structure design and coupling technology. Utilizing a multi-lens adjustable collimating lens group with each lens collinearly arranged along the optical axis of the laser transmission direction, it can specifically reduce the diffusion angle of red, green, and blue lasers. After emission from the laser, the laser beam is a diffused elliptical beam. Through step-by-step calibration and relative position optimization of each lens in the collimating lens group, the consistency of the beam propagation direction is significantly improved, effectively reducing scattering and interference during laser propagation. From the coupling technology perspective, during coupling, a beam quality analyzer detects the speckle shape in real time at different close-range positions at the output port of the beam combining prism group, accurately determining the light divergence angle and adjusting the collimating lens group accordingly. This ensures that the collimation effect of each lens reaches its optimal level, allowing the laser beam to be highly concentrated. This completely changes the problem of speckle formation caused by uneven beam diffusion and interference in traditional laser projection. The resulting coupled optical imaging system projects an image without graininess, with clear edge contours and sharper details, significantly improving the visual clarity experience of in-vehicle projection.

[0021] 2. This invention achieves stable and accurate color reproduction by utilizing an integrated beam-splitting and beam-combining structure design and precise coupling technology of a beam-combining prism assembly. The beam-combining prism assembly adopts a beam-splitting prism layout corresponding to the three-color laser, with each prism's incident surface precisely matched to the laser's output direction. The output surfaces are coplanar and coated with a three-color compatible beam-combining film, enabling the collimated three-color laser to be focused into a single polychromatic beam without deflection or loss. This avoids the uneven color mixing caused by optical path offset in traditional beam-combining structures. Furthermore, it provides two schemes: distributed collimation coupling and simultaneous coupling. Distributed coupling allows for individual collimation of each color laser. Calibration and repeated testing ensure the precise transmission path of the single-color laser. At the same time, coupling through multi-channel detection and linkage adjustment achieves synchronous optimization of the collimation effect of the three-color laser. Both schemes can guarantee the light intensity and phase compatibility of the three-color laser during the light combination process, so that the color output of the coupled optical system remains stable and will not shift due to changes in the vehicle environment or long-term use. This effectively solves the problems of color reproduction distortion and harsh transition between light and dark in traditional vehicle projection optical engines, making the image color highly consistent with the original signal, and fully preserving the details in the dark areas and the layers in the bright areas, resulting in richer and more natural color performance. Attached Figure Description

[0022] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the overall assembly structure of a vehicle-mounted LBS projection optical engine proposed in this invention; Figure 2 This is a schematic diagram of the pre-assembly structure of the light source component of a vehicle-mounted LBS projection optical engine proposed in this invention; Figure 3 This is a schematic diagram of the disassembly structure of the collimating lens assembly housing of a vehicle-mounted LBS projection optical engine proposed in this invention; Figure 4 This is a schematic diagram of the overall optical coupling structure of a vehicle-mounted LBS projection optical engine proposed in this invention; Figure 5 This is a schematic diagram of the connection structure between the outer shell and the base of a vehicle-mounted LBS projection optical engine proposed in this invention. Figure 6 This is a flowchart illustrating the optical coupling method for a vehicle-mounted LBS projection optical engine proposed in this invention.

[0023] In the diagram: 1. Bottom shell; 2. PCBA-L; 3. Bracket; 4. Outer shell; 5. Base; 6. Dust cover; 7. Beam combining lens; 8. Beam combining prism group; 9. Collimating lens group; 10. Laser; 11. PCBA-S; 12. MEMS scanning imaging system; 13. Lens fixing frame; 14. Elastic buffer ring; 15. Positioning boss; 16. Sealing groove; 17. Heat dissipation fins; 18. Waterproof rubber strip; 19. Dustproof mesh. Detailed Implementation

[0024] To make the technical means and objectives and effects of the present invention easier to understand, the embodiments of the present invention will be described in detail below with reference to specific illustrations.

[0025] like Figure 1-4 As shown, this invention discloses an in-vehicle LBS projection optical engine, which aims to solve the technical problems of existing in-vehicle laser projection optical engines, such as speckle affecting clarity and unstable color calibration. By optimizing the optical structure design and coupling process, the imaging quality is improved, adapting to the complex usage requirements of the in-vehicle environment.

[0026] The vehicle-mounted LBS projection optical engine includes a base 5, a laser 10, a collimating lens group 9, a beam combining prism group 8, a dust cover 6, a PCBA-S11, a housing 4, and a MEMS scanning imaging system. Among them, the base 5, as the core installation carrier, is made of high-strength engineering plastic through one-piece injection molding. Its surface is precision machined to ensure that the flatness and perpendicularity of the installation surface meet the requirements of optical assembly. The preset installation groove is precisely matched with the outer contour of the laser 10, and the inner wall of the installation groove is provided with positioning ribs to assist the initial positioning of the laser 10.

[0027] The laser 10 is a red, green and blue semiconductor laser 10. The output power and wavelength of each color laser 10 are adapted to the brightness requirements of the vehicle projection. The laser 10 is fixed in the mounting groove of the base 5 by dispensing adhesive. The dispensing area is evenly distributed along the bottom edge of the laser 10 to ensure that the output direction of the fixed laser 10 is strictly consistent with the optical axis of the subsequent optical components without any offset deviation.

[0028] The collimating lens group 9 is located on the light-emitting side of the laser 10 and consists of three cemented doublet lenses 19. Each cemented doublet lens 19 is arranged sequentially along the laser transmission direction according to the focal length gradient. The first lens closest to the laser 10 has the smallest focal length and is mainly used to quickly reduce the large-angle diffusion of the laser. The second lens in the middle has a central focal length and plays a transitional calibration role. The third lens furthest from the laser 10 has the largest focal length and achieves fine calibration of the laser transmission direction.

[0029] The material of each cemented doublet lens 19 is selected according to the characteristics of the corresponding laser wavelength. The lens adapted to red light uses low dispersion optical glass to effectively reduce dispersion during the transmission of red light; the lens adapted to green and blue light uses high transmittance optical glass to reduce light energy loss.

[0030] The collimating lens group 9 has a lens fixing frame on its outer side. The frame is made of lightweight aluminum alloy and has positioning holes that are compatible with each lens. An elastic buffer ring is bonded to the inner wall of the positioning hole. The buffer ring is made of silicone rubber and its inner diameter is interference fit with the outer diameter of the lens. This ensures that the optical axis of each lens is accurately aligned and can also reduce the impact force in the vehicle vibration environment, thus preventing the lens position from shifting.

[0031] The beam combining prism group 8 is located on the light-emitting side of the collimating lens group 9. It includes three independent beam splitting prisms. The three beam splitting prisms are arranged in a compact triangular pattern in the preset mounting area of ​​the base 5. The mounting area is provided with positioning grooves that fit the bottom of the prisms to ensure the horizontality of the prisms after installation. The beam combining prism group 8 has a beam combining lens 7 built in.

[0032] The incident surface of each beam splitter is at a 45° angle to the output direction of the corresponding laser 10. The incident surface is coated with an antireflection film of the corresponding wavelength through a vacuum coating process. The antireflection film of the incident surface of the red light prism is optimized for wavelengths of 620-660nm, the antireflection film of the incident surface of the green light prism is optimized for wavelengths of 520-560nm, and the antireflection film of the incident surface of the blue light prism is optimized for wavelengths of 440-480nm. This greatly reduces the reflection loss of the laser at the incident surface and improves the light transmission efficiency.

[0033] The light-emitting surfaces of the three beam splitters are on the same plane, and each light-emitting surface is coated with a three-color compatible light-combining film. This light-combining film enables the three wavelengths of laser light to converge along the same optical axis after reflection and refraction to form a single beam of polychromatic light, ensuring uniform color mixing.

[0034] The base 5 is provided with an annular positioning boss at the installation position of the beam splitter prism. The boss fits tightly with the side of the prism and is fixed with edge adhesive to form a double positioning, which effectively prevents the prism from shifting due to vehicle bumps.

[0035] The dust cover 6 adopts a double-layer composite structure. The inner layer is optical-grade transparent quartz glass, which has high light transmittance and low optical distortion characteristics to ensure the transmission of polychromatic light without deviation. The outer layer is made of impact-resistant polycarbonate material, which can resist minor collisions and foreign object impacts in the vehicle environment and protect the internal optical components.

[0036] A 0.5-1mm heat dissipation gap is reserved between the two layers. Micro heat dissipation fins are integrally formed in the gap. The fins are arranged along the direction of polychromatic light transmission. While not affecting the light transmission, they can quickly dissipate the heat generated by the light combining prism group 8 during operation, avoiding the impact of high temperature on optical performance.

[0037] The light-transmitting port 17 of the dust cover is designed to be circular, and the diameter of the light-transmitting port 17 is slightly larger than the beam diameter of the polychromatic light. The inner edge of the light-transmitting port 17 of the dust cover is rounded, and the radius of the rounded corner is determined according to the optical design parameters to effectively avoid the laser from generating diffraction at the edge.

[0038] The inner side of the light-transmitting port 17 of the dust cover is coated with a full-band anti-reflection film through a vacuum coating process. The transmittance of the anti-reflection film to red, green and blue lasers is not less than 98%, and the film layer has been treated to withstand high and low temperatures and resist aging, so it can adapt to long-term use in the vehicle environment.

[0039] An annular sealing groove is provided at the sealing point between the dust cover 6 and the base 5. The cross-section of the sealing groove is trapezoidal and the groove is filled with high-temperature resistant silicone. The silicone is evenly filled by dispensing process. Pressing the dust cover 6 makes the silicone fully adhere to each surface of the sealing groove. After curing, a continuous and gapless sealing ring is formed, which can effectively prevent dust and moisture from entering the optical components and ensure stable optical performance.

[0040] In addition, the vehicle-mounted LBS projection optical engine also includes a base shell, PCBA-L and bracket. The base shell is made of aluminum alloy and the surface is anodized to form a dense oxide film, which has good rust prevention performance and can improve heat conduction efficiency.

[0041] The bottom shell has multiple interconnected heat dissipation channels inside, and the direction of the channels corresponds to the heat-generating areas of the internal components. Small cooling fans can be installed in the channels according to actual heat dissipation needs. After the fans are turned on, they can accelerate air circulation and quickly remove internal heat.

[0042] The bracket has a hollow structure and is made of engineering plastic in one piece. The hollow design reduces the overall weight without affecting heat dissipation. The two ends of the bracket are fixed to the upper surface of the bottom shell and the lower surface of the outer shell by bolts. Anti-loosening washers are provided at the bolt connection to prevent the bolts from loosening due to vehicle vibration.

[0043] The connection between the bracket and the housing 4 is equipped with a shock-absorbing pad. The shock-absorbing pad is made of nitrile rubber, which has good elasticity and shock absorption performance, and can effectively absorb vehicle vibration and reduce the transmission of vibration to optical components.

[0044] PCBA-L is a multi-layer circuit board that is fixed to the circuit board bracket inside the bottom shell by a snap-fit ​​structure, making installation and disassembly convenient. PCBA-L and PCBA-S11 are connected by shielded wires. The outer layer of the shielded wires has a metal braided shielding layer, which can effectively reduce electromagnetic interference in the vehicle environment and ensure stable transmission of electrical signals.

[0045] The PCBA-L integrates a power management module, a signal processing module, and a communication module. The power management module converts the vehicle's power supply into a stable voltage required by each component and features overvoltage and overcurrent protection. The signal processing module optimizes the control signals of the MEMS scanning imaging system, improving imaging stability and clarity. The communication module uses the CAN bus communication protocol to achieve bidirectional data transmission with the vehicle's central control system and supports real-time adjustment of projection parameters. The bottom shell has a waterproof strip along its edge, which fits tightly into the groove of the bottom shell. A dustproof mesh made of stainless steel with small mesh openings is located at the junction of the bottom shell and the outer shell 4, effectively preventing dust from entering without affecting heat dissipation and ventilation, further enhancing the overall dust and water resistance of the device.

[0046] The MEMS scanning imaging system is located on the light-emitting side of the light-transmitting port 18 of the housing and is fixed to the housing 4 by bolts. The distance between its receiving end and the light-transmitting port 18 of the housing is determined according to the optical design parameters. The polychromatic light after being converged by the light-combining prism group 8 is first focused by the built-in light-combining lens 7. The focused beam is incident on the surface of the reflector of the MEMS scanning imaging system. The MEMS reflector deflects at high speed under the control of the driving signal, scanning the beam to form a complete image and projecting it onto the target area.

[0047] like Figure 1-4 As shown, the present invention also discloses an optical coupling method for an on-board LBS projection optical engine, specifically including the following steps: S1. First, thoroughly clean the surface of the base 5 and the mounting groove. First, use a lint-free cloth dampened with anhydrous ethanol to gently wipe the surface of the base 5 and the inner wall of the mounting groove to remove oil and fingerprints. Avoid using excessive force during wiping to prevent scratching the surface. Then, use a high-pressure air gun to blow away any tiny impurities and residual ethanol vapors in the mounting groove. Adjust the air pressure of the high-pressure air gun to a suitable range to avoid damaging the positioning structure of the mounting groove with excessive air pressure, and ensure that there are no foreign objects on the mounting surface.

[0048] The bottom of the laser 10 is uniformly coated with a conductive and thermally conductive adhesive using a dispensing process. This adhesive has good electrical conductivity, which can ensure the grounding of the laser 10 and the base 5 and reduce electromagnetic interference. It also has a high thermal conductivity, which can help the laser 10 dissipate the heat generated during operation and avoid overheating damage. After curing, it has a certain degree of elasticity, which can alleviate the thermal stress of the laser 10 during operation.

[0049] The laser 10 coated with adhesive is slowly pressed into the mounting groove of the base 5. The output direction of the laser 10 is calibrated by an optical alignment fixture. The reference light emitted by the optical alignment fixture coincides with the preset optical reference axis on the base 5. By observing the relative position of the laser 10 output port and the reference light, the attitude of the laser 10 is adjusted so that the optical axis of the laser 10 is precisely aligned with the preset optical reference axis on the base 5.

[0050] After calibration, UV-curable adhesive is evenly applied through a dispensing controller at the gap between the laser 10 and the mounting slot. The dispensing controller precisely controls the amount of adhesive to ensure uniform adhesive layer thickness and prevent the laser 10 from tilting due to uneven adhesive layer. The UV-curable adhesive is then cured by irradiation with a UV lamp. The irradiation time is adjusted according to the curing characteristics of the adhesive, typically 30-60 seconds. After curing, the deviation between the optical axis of the laser 10 and the reference axis of the base 5 is detected using an optical inspection fixture, such as a laser interferometer. If the deviation exceeds the tolerance, the UV-curable adhesive is softened by heating with a heating fixture, and the position of the laser 10 is recalibrated until the deviation meets the system's preset requirements.

[0051] S2. Using a multi-axis clamping fixture 12, each lens of the collimating lens group 9 is placed in the designed position on the light-emitting side of the laser 10. The multi-axis clamping fixture 12 has adjustment functions in three directions: X, Y, and Z. The positioning reference block of the fixture ensures that the optical axis of each lens is initially aligned with the optical axis of the laser 10, and the alignment accuracy is controlled within a preset range.

[0052] Place the beam combining prism group 8 on the prism positioning protrusion of the base 5, and gently press it to make the bottom of the prism fit into the positioning groove. Adjust the prism posture by visual inspection and simple tooling to make the incident surface of the prism accurately correspond to the light output side of the collimating lens group 9, so that the laser can be smoothly incident on the incident surface of the prism.

[0053] Based on the actual assembly accuracy requirements, preliminary adhesive pre-fixation can be performed on the edge of the fixed frame of the collimating lens group 9 and the side of the beam combining prism group 8. The pre-fixation uses a low-viscosity instant adhesive with a small amount of adhesive, which only serves as a temporary fixation. During subsequent adjustments, the position can be corrected by dissolving the adhesive with a special solvent to prevent the components from shifting during subsequent adjustments.

[0054] The collimation method of collimating lens group 9 can be selected as distributed collimation coupling or simultaneous coupling. Distributed collimation coupling is suitable for small-batch, high-precision assembly scenarios. The specific operation procedure is as follows: First, light up the red laser 10 separately. Then, use a beam quality analyzer to detect the divergence angle of the red light spot after passing through the collimating lens group 9. Slowly adjust the position of the lens corresponding to the red light. After each adjustment, pause for a period of time and detect again after the spot stabilizes until the divergence angle reaches the system's preset standard. Then, turn on the green laser 10 separately and repeat the above adjustment process. When adjusting the green lens, the divergence angle of the red light spot should be re-measured at the same time to avoid the adjustment of the green lens affecting the collimation effect of the red light. Finally, the blue laser 10 is lit separately to complete the adjustment of the blue lens, ensuring that the divergence angles of the red, green, and blue lasers all meet the system requirements.

[0055] Simultaneous coupling is suitable for high-volume production scenarios. The specific operation process is as follows: The red, green, and blue lasers 10 are lit simultaneously. A multi-channel beam quality analyzer is used to simultaneously detect the divergence angle and shape of the three-color laser spots. Multiple lenses are adjusted synchronously using a linkage fine-tuning fixture. This fixture has a real-time feedback function and can display the adjustment amount of each lens, avoiding mutual interference when different lenses are adjusted. The adjustment continues until the divergence angle of the three-color lasers all meet the system preset requirements. The appropriate coupling method can be selected according to the actual production needs.

[0056] S3. Secure the assembled components from step S2 horizontally to the high-precision fixed base 13 using pressure plates and bolts. The flatness error of the high-precision fixed base 13 shall not exceed 0.01mm to ensure that the components do not shake or shift during the adjustment process.

[0057] Powering on the components provides a stable operating voltage to the laser 10 via PCBA-S11, enabling the laser 10 to emit laser light stably and preventing unstable laser parameters due to voltage fluctuations.

[0058] Using a beam quality analyzer, the beam pattern was measured at two different close-range positions in front of the light outlet of beam combining prism group 8. The size, shape and other parameters of the beam at the two positions were recorded. Based on these parameters, the divergence angle of the light was calculated and determined.

[0059] The front-to-back position and relative spacing of each lens in the collimating lens group 9 can be changed by adjusting the fine-tuning knob of the clamping fixture 12. The adjustment accuracy of the fine-tuning knob can reach the micrometer level. During the adjustment process, the vacuum adsorption fixture 14 is used to help fix the lens and prevent the lens from shifting.

[0060] The suction head of the vacuum adsorption fixture 14 is made of soft silicone. The shape of the suction head is precisely matched with the outer contour of the lens to avoid scratching the lens surface during adsorption. The adsorption pressure is monitored in real time by a pressure sensor and kept in a constant range of 0.02-0.05MPa. Excessive pressure will cause the lens to deform, while insufficient pressure will prevent the lens from being stably fixed.

[0061] After each adjustment, pause for 5-10 seconds until the beam quality analyzer's detection data stabilizes, then determine whether the divergence angle meets the standard. Continue adjusting and repeatedly detecting the beam spot until the beam divergence angle meets the system's preset collimation requirements.

[0062] Then, UV-curing adhesive is applied to the gaps between each lens and the fixed frame, and left to stand until the adhesive is completely cured, thus completing the fixation of the collimating lens group 9.

[0063] After the collimating lens group 9 is fixed, a stability test is required. The component is powered on and operates continuously for 1 hour. During this period, the beam divergence angle is checked every 15 minutes to confirm that the lens does not shift due to the curing and shrinkage of the glue, thus ensuring long-term stability of the collimation effect.

[0064] S4. Assemble the optically coupled components from step S3 with the dust cover 6, and adjust the position of the dust cover 6 so that the light-transmitting port 17 of the dust cover is precisely aligned with the light-emitting path of the light-combining prism group 8, ensuring that the polychromatic light can pass through the light-transmitting port 17 of the dust cover without obstruction or deviation.

[0065] High-temperature resistant silicone is evenly filled into the sealing groove between the dust cover 6 and the base 5 using a dispensing process. During the filling process, it is ensured that the silicone is free of air bubbles and voids. The dust cover 6 is pressed to make the silicone fully adhere to each surface of the sealing groove. The mixture is left to stand until the silicone is completely cured, thus achieving a sealed and fixed connection between the dust cover 6 and the base 5.

[0066] The assembled components are soldered to PCBA-S11 using a reflow soldering process. The temperature profile of the reflow soldering is set according to the characteristics of the soldered components to ensure that the solder joints are strong and reliable. After soldering, the continuity of the circuit is tested with a multimeter, and the connection lines between the laser 10 and PCBA-S11 are tested one by one to ensure that there are no open circuits or short circuits, thus forming a complete light source assembly 15.

[0067] S5. The light source assembly 15 is horizontally placed into the housing mounting groove 16 using a vacuum clamping fixture 12. The suction force of the vacuum clamping fixture 12 is moderate to avoid damaging the surface structure of the light source assembly 15.

[0068] The position of the light source assembly 15 inside the housing 4 is adjusted by a laser alignment fixture. The reference laser wavelength emitted by the laser alignment fixture is consistent with the laser wavelength of the projection optical engine to ensure alignment accuracy. The detection probes of the alignment instrument are respectively set inside the light-transmitting port 17 of the dust cover and outside the light-transmitting port 18 of the housing. By measuring the deviation of the reference laser signals received by the two probes, it is determined whether the centers of the two light-transmitting ports coincide. The position of the light source assembly 15 is gradually adjusted until the signal deviation is less than the preset threshold, thus completing the coaxiality adjustment.

[0069] The beam quality analyzer is used to gradually move and observe near the theoretical optimal convergence position of the beam. First, the range of the theoretical optimal convergence position is determined according to the optical design parameters. Within this range, the beam quality analyzer is moved in a zigzag path, pausing for 3-5 seconds after each movement. After the detection data stabilizes, the area of ​​the light spot, the brightness uniformity, and the center offset are recorded. By comparing all the recorded data, the position with the smallest light spot area, the highest brightness, and the best uniformity is selected as the optimal coupling position.

[0070] UV-curable adhesive is evenly applied through a dispensing process at the gap between the light source assembly 15 and the housing mounting groove 16. The application is allowed to stand until the adhesive is completely cured, thus fixing the light source assembly 15 and achieving optical coupling of the entire device. After fixing the light source assembly 15, the coaxiality and light spot status of the two sets of light ports need to be checked again to confirm that there are no deviations caused by adhesive curing shrinkage. If deviations exist, the cause needs to be analyzed and corrective measures taken, such as local heating to soften the adhesive for fine-tuning, to ensure that the overall coupling accuracy meets the requirements.

[0071] Through the above structural design and coupling method, the vehicle-mounted LBS projection optical engine can effectively reduce the laser diffusion angle, eliminate speckle phenomenon, and improve imaging clarity. At the same time, it ensures uniform and stable color mixing of the three-color lasers, improves the problems of color reproduction distortion and loss of detail, and the overall structure has good shock resistance, dustproof, waterproof and heat dissipation performance, can adapt to the complex use conditions of the vehicle environment, and has high practicality and reliability.

[0072] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A vehicle-mounted LBS projection optical engine, characterized in that, Includes a base (5), a laser (10), a collimating lens group (9), a beam combining prism group (8), a dust cover (6), a PCBA-S (11), a housing (4), and a MEMS scanning imaging system; The laser (10) is fixed in the mounting groove of the base (5) by dispensing adhesive, and the light output direction of the laser (10) is consistent with the optical axis of the subsequent optical components. The collimating lens group (9) is located on the light-emitting side of the laser (10) and is used to reduce the diffusion angle of the laser emitted by the laser (10). The collimating lens group (9) is a multi-piece adjustable structure. Each lens is arranged sequentially along the laser transmission direction and the optical axis is collinear. The collimation effect can be optimized by adjusting the relative position of each lens. The beam combining prism group (8) is located on the light-emitting side of the collimating lens group (9). It adopts an integrated beam splitting and beam combining design, and can receive red, green and blue lasers after being processed by the collimating lens group (9), and converge the three lasers into a single beam of polychromatic light without deflection. The beam combining prism group (8) has a beam combining lens (7) built in. The dust cover (6) is installed on the outside of the light combining prism group (8), and its edge is sealed and fixed to the base (5) by adhesive to prevent external impurities from entering the optical component. The dust cover (6) has a dust cover light passage (17), which corresponds to the light output path of the light combining prism group (8). The PCBA-S (11) is electrically connected to the laser (10) by welding, and is used to provide power supply support and control signals for the laser (10); The light source assembly (15), consisting of the base (5), laser (10), collimating lens group (9), beam combining prism group (8), dust cover (6) and PCBA-S (11), is installed in the mounting groove inside the housing (4). The light-transmitting port (17) of the dust cover and the corresponding light-transmitting port (18) on the housing (4) are coaxially arranged to ensure that the polychromatic light can be transmitted stably. The MEMS scanning imaging system is located on the light-emitting side of the light-transmitting port (18) of the outer shell. The polychromatic light, after being converged by the light-combining prism group (8), is first focused and then incident on the MEMS scanning imaging system, which completes the final imaging.

2. The vehicle-mounted LBS projection optical engine according to claim 1, characterized in that, Each lens in the collimating lens group (9) is a cemented doublet lens (19). Each cemented doublet lens (19) is arranged in sequence along the laser transmission direction according to the focal length gradient. The lens closer to the laser (10) has a smaller focal length, which is used to initially reduce the large-angle diffusion of the laser. The lens farther away from the laser (10) has a larger focal length, which is used to finely calibrate the transmission direction of the laser. The material of each of the doublet lenses (19) is selected according to the wavelength characteristics of red, green and blue lasers. The lens adapted to red light is made of low dispersion optical glass, and the lens adapted to green and blue light is made of high transmittance optical glass to reduce the transmission loss and color difference of lasers of different wavelengths. The collimating lens group (9) has a lens fixing frame on its outer side. The frame has positioning holes that are adapted to each lens. The inner wall of the positioning hole is provided with an elastic buffer ring, which can ensure the alignment of the lens optical axis and reduce the influence of vehicle vibration on the lens position.

3. The vehicle-mounted LBS projection optical engine according to claim 1, characterized in that, The beam combining prism group (8) includes three independent beam splitting prisms. The three beam splitting prisms correspond one-to-one with the output paths of the red, green and blue lasers (10), and the three beam splitting prisms are arranged in a triangular pattern in the preset installation area of ​​the base (5). The incident surface of each of the beam splitters is at a 45° angle to the light output direction of the corresponding laser (10), and the incident surface is coated with an anti-reflection film of the corresponding wavelength to reduce the reflection loss of the laser at the incident surface. The light-emitting surfaces of the three beam splitters are on the same plane, and each light-emitting surface is coated with a three-color compatible light-combining film to ensure that the three-color lasers can converge into polychromatic light along the same optical axis after reflection and refraction. The base (5) is provided with a positioning boss corresponding to the installation position of the beam splitter prism. The boss fits against the side of the prism and is fixed with glue to prevent the prism from shifting due to vehicle bumps.

4. The vehicle-mounted LBS projection optical engine according to claim 1, characterized in that, The dust cover (6) adopts a double-layer composite structure, with the inner layer being optical-grade transparent quartz glass and the outer layer being impact-resistant polycarbonate material. A heat dissipation gap of 0.5-1mm is reserved between the two layers, and micro heat dissipation fins are provided in the gap to assist the light-combining prism group (8) in dissipating working heat. The light-transmitting port (17) of the dust cover is circular. The inner edge of the light-transmitting port (17) of the dust cover is rounded to avoid laser diffraction at the edge. The inner side of the light-transmitting port (17) of the dust cover is coated with a full-band anti-reflection film. The transmittance of the anti-reflection film to red, green and blue lasers is not less than 98%. The film layer has high and low temperature resistance and anti-aging properties, and is suitable for long-term use in vehicles. The dust cover (6) and the base (5) are sealed with an annular sealing groove, and the annular sealing groove is filled with high-temperature resistant silicone. After the silicone is cured, it forms a continuous sealing ring to prevent dust and moisture from entering the optical component.

5. A vehicle-mounted LBS projection optical engine according to claim 1, characterized in that, It also includes the bottom shell (1), PCBA-L2 and bracket 3; The bottom shell (1) is made of aluminum alloy and has an anodized layer on the surface, which has rust prevention and heat conduction properties. Multiple heat dissipation channels are opened inside the bottom shell (1), and cooling fans can be installed in the channels as needed. The bracket 3 is a hollow structure, made of engineering plastic in one piece. The two ends of the bracket are fixed to the upper surface of the bottom shell (1) and the lower surface of the outer shell (4) by bolts, and the connection between the bracket 3 and the outer shell (4) is provided with shock-absorbing pads to reduce the transmission of vehicle vibration to the optical components. The PCBA-L2 is a multi-layer circuit board, fixed on the circuit board bracket inside the bottom shell (1). PCBA-L2 and PCBA-S (11) are connected by shielded wires. PCBA-L2 integrates a power management module, a signal processing module and a communication module. The power management module provides a stable voltage for the entire projection optical engine. The signal processing module optimizes the control signal of the MEMS scanning imaging system. The communication module realizes bidirectional data transmission with the vehicle central control system. The bottom shell (1) is provided with a waterproof strip on its edge, and a dustproof net is provided at the joint between the bottom shell (1) and the outer shell (4) to further enhance the dustproof and waterproof capabilities of the whole machine.

6. An optical coupling method for a vehicle-mounted LBS projection optical engine, characterized in that, According to any one of claims 1-5, the vehicle-mounted LBS projection optical engine includes the following steps: S1. Clean the surface of the base (5) and the mounting groove. First, wipe the surface with anhydrous ethanol to remove the oil stains. Then, blow away the small impurities in the mounting groove with a high-pressure air gun to ensure that there are no foreign objects on the mounting surface. After uniformly coating the bottom of the laser (10) with adhesive, slowly press it into the mounting groove of the base (5). Use an optical alignment tool to calibrate the light output direction of the laser (10) so that the optical axis of the laser (10) is aligned with the preset optical reference axis on the base (5). After calibration, apply glue evenly to the gap between the laser (10) and the mounting groove and let it stand until the glue cures to complete the fixation of the laser (10). S2. Using a multi-axis clamping fixture (12), each lens of the collimating lens group (9) is placed in the designed position on the light-emitting side of the laser (10). The positioning reference of the fixture ensures that the optical axis of each lens is initially aligned with the optical axis of the laser (10). The beam combining prism group (8) is placed on the prism positioning boss of the base (5). The prism posture is adjusted so that the incident surface of the prism corresponds to the light-emitting side of the collimating lens group (9). According to the actual assembly accuracy requirements, the fixed frame edge of the collimating lens group (9) and the side of the beam combining prism group (8) can be pre-fixed with glue to prevent the components from shifting during subsequent adjustments. S3. Secure the assembled components from step S2 horizontally to the high-precision fixed base (13) to ensure that the components do not shake during the adjustment process. Power on the components to make the laser (10) emit laser stably. Use a beam quality analyzer to measure the shape of the light spot at two different close-range positions in front of the light outlet of the beam combining prism group (8). Calculate and judge the size of the divergence angle of the light based on the size and shape difference of the light spot at the two positions. Change the front and rear positions and relative spacing of each lens in the collimating lens group (9) by adjusting the fine adjustment knob of the clamping fixture (12). At the same time, use the vacuum adsorption fixture (14) to assist in fixing the lens. Continuously adjust and repeatedly test the light spot until the divergence angle of the light meets the collimation requirements preset by the system. Then apply glue to the gap between each lens and the fixed frame and let it stand until the glue cures to complete the fixing of the collimating lens group (9). S4. Assemble the optically coupled components from step S3 with the dust cover (6), ensuring that the light-transmitting port (17) of the dust cover is precisely aligned with the light-emitting path of the light-combining prism group (8), so that the polychromatic light can be transmitted without obstruction. Fill the sealing groove between the dust cover (6) and the base (5) with sealant, press the dust cover (6) to make the sealant fully adhere to the sealing groove, and let it stand until the sealant cures to achieve the sealing and fixing of the dust cover (6) and the base (5). Connect the assembled components to the PCBA-S (11) through reflow soldering. After soldering, use a multimeter to test the circuit continuity to ensure that there is no open circuit or short circuit in the electrical signal between the PCBA-S (11) and the laser (10), thus forming a complete light source component (15). S5. Using a vacuum clamping fixture (12), the light source assembly (15) is horizontally placed into the housing mounting slot (16). The position of the light source assembly (15) in the housing (4) is adjusted by using a laser alignment fixture so that the light port (17) of the dust cover is aligned with the light port (18) of the housing and remains coaxial. The beam quality analyzer is used to gradually move and observe near the theoretical best beam convergence position, and the brightness, size and uniformity of the light spot at different positions are recorded until the smallest and brightest light spot is observed. Glue is evenly applied to the gap between the light source assembly (15) and the housing mounting slot (16), and left to stand until the glue is completely cured to complete the fixation of the light source assembly (15) and thus realize the optical coupling of the whole machine.

7. The optical coupling method for a vehicle-mounted LBS projection optical engine according to claim 6, characterized in that, In step S2, the collimation mode of the collimating lens group (9) can be selected as distributed collimation coupling or simultaneous coupling. The specific operation process of distributed collimation coupling is as follows: First, light up the red laser (10) separately, and use a beam quality analyzer to detect the divergence angle of the red light spot after passing through the collimating lens group (9). Adjust the position of the lens corresponding to the red light until the divergence angle meets the standard. Then turn on the green laser (10) separately and repeat the above adjustment process; Finally, the blue laser (10) is lit separately to complete the blue lens adjustment and ensure that the divergence angles of the three lasers meet the requirements. The specific operation process for simultaneous coupling is as follows: Simultaneously light up red, green and blue lasers (10), use a multi-channel beam quality analyzer to detect the three-color spots at the same time, and use a linkage fine-tuning fixture to adjust multiple lenses at the same time until the divergence angle of the three-color lasers meets the system requirements. The distributed collimation coupling is suitable for small-batch, high-precision assembly scenarios, while the coupling is suitable for large-batch production scenarios. The appropriate coupling method can be selected according to actual production needs.

8. The optical coupling method for a vehicle-mounted LBS projection optical engine according to claim 6, characterized in that, In step S1, the adhesive coated on the bottom of the laser (10) is a conductive and thermally conductive adhesive. The conductive and thermally conductive adhesive has both good conductivity and high thermal conductivity. After curing, the conductive and thermally conductive adhesive has a certain elasticity, which can alleviate the thermal stress of the laser (10) during operation. The adhesive is fixed by UV curing adhesive. During the dispensing process, the amount of adhesive is precisely controlled by the dispensing controller to ensure that the adhesive layer thickness is uniform. When the adhesive is cured, it is irradiated by UV lamp. The irradiation time is adjusted according to the characteristics of the adhesive. After curing, the deviation between the optical axis of the laser (10) and the reference axis of the base (5) is detected by optical detection fixture. If the deviation exceeds the tolerance, the adhesive can be softened by heating fixture, and the position of the laser (10) can be recalibrated until the deviation meets the requirements.

9. The optical coupling method for a vehicle-mounted LBS projection optical engine according to claim 6, characterized in that, In step S3, the adsorption head of the vacuum adsorption fixture (14) is made of soft silicone. The shape of the adsorption head is adapted to the outer contour of the lens to avoid scratching the lens surface during adsorption. The adsorption pressure is monitored in real time by a pressure sensor and kept in a constant range of 0.02-0.05MPa. When adjusting the lens position, a piezoelectric ceramic driven fine-tuning fixture is used. The adjustment accuracy can reach the micron level. After each adjustment, it is paused for 5-10 seconds. After the detection data of the beam quality analyzer is stable, it is judged whether the divergence angle meets the standard. After the collimating lens group (9) is fixed, a stability test is required. The component is powered on and works continuously for 1 hour. During this period, the beam divergence angle is detected every 15 minutes to confirm that the lens has not shifted due to the curing and shrinkage of the glue, and to ensure that the collimation effect is stable for a long time.

10. The optical coupling method for a vehicle-mounted LBS projection optical engine according to claim 6, characterized in that, In step S5, when adjusting the coaxiality of the dust cover light-transmitting port (17) and the outer shell light-transmitting port (18), a high-precision laser alignment instrument is used for auxiliary detection. The reference laser wavelength emitted by the alignment instrument is consistent with the laser wavelength of the projection optical engine. The detection probes of the alignment instrument are respectively set inside the dust cover light-transmitting port (17) and outside the outer shell light-transmitting port (18). By measuring the deviation of the reference laser signals received by the two probes, it is determined whether the centers of the two light-transmitting ports coincide. The position of the light source component (15) is gradually adjusted until the signal deviation is less than the preset threshold, thus completing the coaxiality adjustment. During the light spot observation process, the optical design parameters are first used to determine the coaxiality adjustment. Determine the range of the theoretically optimal convergence position. Within this range, move the beam quality analyzer along a zigzag path, pausing for 3-5 seconds after each movement. Once the detection data stabilizes, record the area, brightness uniformity, and center offset of the light spot. By comparing all recorded data, select the position with the smallest light spot area, the highest brightness, and the best uniformity as the optimal coupling position. After the light source assembly (15) is fixed, the coaxiality of the two light ports and the light spot status need to be checked again to confirm that there is no deviation caused by the curing shrinkage of the glue. If there is a deviation, the cause of the deviation needs to be analyzed and corrective measures need to be taken to ensure that the coupling accuracy of the whole machine meets the requirements.

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