Laser projection system based on focal depth continuation focusing

Abstract

The invention provides a laser projection system based on focal depth continuation focusing, which belongs to the technical field of laser projection and comprises a laser coupling device, an RGB (red, green and blue) light mixing device, a focal depth continuation focusing module, a sheet homogenizing device, a pattern sheet and a laser projection module which are sequentially arranged. The focal depth continuation focusing module carries out focal depth continuation and focusing on the mixed light beams to form a focal depth continuation area; and the sheet homogenizing device is arranged in the area and is used for homogenizing and mixing the laser. The optimal placement range of the pattern sheet is expanded through focal depth continuation, and the problem that the image quality is affected due to the fact that the pattern sheet cannot be close to the light-emitting surface of the light mixing device is solved; meanwhile, multi-point sub-beam arrangement is disorganized by the sheet homogenizing device, the near-field laser beam splitting phenomenon is eliminated, and the beam quality and uniformity are improved. The system is compact in structure, and is suitable for long-distance and high-definition pattern projection occasions.

Description

Technical Field

[0001] This invention relates to the field of laser projection technology, and in particular to a laser projection system based on depth-of-focus extension focusing. Background Technology

[0002] In an RGB laser three-in-one light source system, the "three" in "three-in-one light source" refers to the integration of three functions: pattern projection, small divergence beam, and color transformation. In existing solutions, the laser beam enters the RGB mixing device through a laser coupling device to achieve RGB three-color mixing. The mixed laser beam then strikes a pattern sheet (which can be a single sheet or multiple pattern sheets with different content mounted via a rotating mechanism). The laser projection module projects the content of the pattern sheet onto the pattern projection area, and the projected beam has minimal divergence, enabling long-distance projection. However, this solution has the following problems: (1) The light-emitting surface of the RGB mixing device is the projection surface, and the light-emitting area is the smallest (equivalent to the focal point). The material is optical glass, which is easily damaged and contaminated, causing the pattern to be unable to get infinitely close to the light-emitting surface of the mixing device, thus affecting the projection quality of the projected pattern.

[0003] (2) The multi-point mixing arrangement of the RGB mixing device and the projection focusing principle of the laser projection module cause the laser beam to split in the near field region of the laser beam (generally about 1-3 meters away from the light output surface of the laser projection module), which seriously affects the beam quality. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art, and proposes a laser projection system based on depth-of-focus extension focusing, which aims to solve the problems of limited pattern placement and near-field laser beam splitting in the prior art.

[0005] In a first aspect, embodiments of the present invention provide a laser projection system based on depth-of-focus extension focusing, comprising: The RGB laser beam, laser coupling device, RGB mixing device, depth-of-focus extension focusing module, thin-film homogenizing device, pattern sheet and laser projection module are arranged sequentially along the optical path; The RGB laser beam enters the RGB mixing device through the laser coupling device to achieve three-color mixing. The mixed laser beam is then extended and focused by the depth-of-focus extension and focusing module, and then homogenized and mixed by the thin-film homogenizing device. Finally, the content of the pattern sheet is projected onto the pattern projection area through the laser projection module to achieve long-distance projection.

[0006] Furthermore, the depth-of-focus extension focusing module includes: The main ray focusing component is used to focus the main rays of each field of view from the light-emitting surface of the RGB mixing device; The principal ray parallel component is used to adjust the principal rays of each field of view after focusing to be parallel to the optical axis and to focus the edge rays of each field of view at the focal plane, forming a symmetrical depth-of-focus extension area centered on the focal plane.

[0007] Furthermore, the main beam focusing component includes at least one single positive lens, selected from one of a biconvex lens, a plano-convex lens, a meniscus lens, a cemented lens, and an aspherical lens; the optical surface of the main beam focusing component is coated with a laser anti-reflection film with a transmittance >99%.

[0008] Furthermore, the working distance L1 of the main ray focusing component is 1.5 to 3.5 mm, and the working distance L1 is the distance from the light-emitting surface of the RGB mixing device to the main ray focusing component; the effective focal length f1 of the main ray focusing component is 3.5 to 4.5 mm, and the effective light-transmitting aperture d1 = 2L1*tg(θ / 2), where θ is the field divergence angle.

[0009] Furthermore, the main ray parallel component includes at least one single positive lens, selected from one of a biconvex lens, a plano-convex lens, a meniscus lens, a cemented lens, and an aspherical lens, with its optical surface coated with a laser anti-reflection coating.

[0010] Furthermore, the working distance L2 of the main ray parallel component is its own effective focal length f2, and the working distance L2 is the distance from the main ray focusing point to the main ray parallel component; the optical surface of the main ray parallel component is coated with a laser anti-reflection film with a transmittance > 99%.

[0011] Furthermore, the surface of the thin-film homogenizing device is etched to form a microscopic scattering structure, which is used to expand the divergence angle of the sub-beams and realize the beam combining of multiple sub-beams to fill the gaps.

[0012] Furthermore, the pattern piece is movably disposed within the depth-of-focus extension region, and the depth-of-focus extension focusing module achieves a depth-of-focus extension of 4mm. Within the formed depth-of-focus extension region, the movement space of the pattern piece is ≥3mm. The depth-of-focus extension region is symmetrically arranged with the focal plane as the center, and the edge focal plane height is ≤1.1H, where H is the focal plane height.

[0013] Furthermore, the depth-of-focus extension focusing module is a telecentric optical structure that controls the angle range of light rays at the edge of each field of view through ray tracing, so that the light rays at the edge of each field of view are focused at the focal plane.

[0014] Furthermore, the pattern piece can be a single piece or multiple pattern pieces with different contents mounted by a rotating mechanism.

[0015] The technical advantages of the laser projection system based on depth-of-focus extension focusing disclosed in this invention are: the optimal placement range of the pattern sheet is expanded by depth-of-focus extension, sub-beam combining is achieved by thin-film homogenization, near-field beam splitting is avoided, high quality of the projected pattern is ensured, long-distance projection is supported, beam divergence is small, and it is highly practical. Attached Figure Description

[0016] Figure 1 A schematic diagram of a laser projection system based on depth-of-focus extension focusing is provided for an embodiment of the present invention; Figure 2 This is a schematic diagram illustrating the effect of a laser projection system based on depth-of-focus extension focusing, as provided in an embodiment of the present invention. Figure 3 This is a schematic diagram of the principle of a laser projection system based on depth-of-focus extension focusing provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the optical path in a laser projection system based on depth-of-focus extension focusing, provided as an embodiment of the present invention. Detailed Implementation

[0017] To enable those skilled in the art to better understand the technical solutions of the present invention, exemplary embodiments of the present invention are described below in conjunction with the accompanying drawings, including various details of the embodiments of the present invention to aid understanding. These should be considered merely exemplary. Therefore, those skilled in the art should recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the present invention. Similarly, for clarity and brevity, descriptions of well-known functions and structures are omitted in the following description.

[0018] A laser projection system based on depth-of-focus extension focusing, reference Figures 1 to 4 As shown, it specifically includes: The system comprises a laser coupling device, an RGB mixing device, a depth-of-focus extension and focusing module, a thin-film homogenizing device, a pattern sheet, and a laser projection module. A laser beam sequentially passes through the laser coupling device, the RGB mixing device, the depth-of-focus extension and focusing module, the thin-film homogenizing device, and the pattern sheet, and is projected onto a projection area via the laser projection module. The depth-of-focus extension and focusing module extends and focuses the light beam from the RGB mixing device's output surface to form a depth-of-focus extension region. The thin-film homogenizing device is disposed within the depth-of-focus extension region and is used to homogenize and mix the focused laser light.

[0019] The laser beam, after undergoing three-color mixing via a coupling device, enters the RGB mixing device and then the depth-of-focus extension focusing module. This system focuses the principal rays of each field of view through a principal ray focusing component, and then uses a principal ray parallelizing component to ensure the principal rays are output parallel to the optical axis. Edge rays are focused at the focal plane, forming a symmetrical depth-of-focus extension region. A thin-film homogenizing device is placed within this region; its surface is etched to form a microscopic scattering structure, which expands the divergence angle of the sub-beams and achieves beam combining. A patterned patch can be placed within this region and can move within a range of at least 2 mm without affecting image quality. Finally, the beam is projected over a long distance with a small divergence angle via a laser projection module.

[0020] Through a complete optical path design, the depth-of-focus extension focusing module and the thin-film homogenizing device are integrated into the traditional RGB laser projection optical path, simultaneously solving two core defects: limited pattern placement and near-field beam splitting. The projected pattern lines have clear and sharp edges, and the brightness uniformity of long-distance projection is ≥90%, improving projection quality by 30% compared to existing technologies. Specifically, through depth-of-focus extension, the pattern can be flexibly placed within the extension area, solving the problem of being unable to approach due to the fragile light-emitting surface of the light-mixing device, thus improving projection quality; the thin-film homogenizing device disrupts the original light spot arrangement, eliminating near-field beam splitting and improving beam uniformity and quality.

[0021] A further refinement of the depth-of-focus extension focusing module includes: a master ray focusing component, used to focus the master rays of each field of view from the light-emitting surface of the RGB mixing device; and a master ray parallelizing component, used to adjust the focused master rays of each field of view to be parallel to the optical axis and to focus the edge rays of each field of view at the focal plane, forming a symmetrical depth-of-focus extension region centered on the focal plane. The combined design of the master ray focusing component and the master ray parallelizing component achieves the synergistic effect of "focusing the master ray + parallel output + edge ray focusing," providing a structural foundation for depth-of-focus extension and increasing the depth-of-focus extension from the existing 0.5mm to 4mm, significantly improving the flexibility of pattern placement.

[0022] A further improved design incorporates a meniscus lens as the main beam focusing component. The working distance L1 of the main beam focusing component is 1.5 to 3.5 mm, where L1 is the distance from the light-emitting surface of the RGB mixing device to the main beam focusing component. The effective focal length f1 of the main beam focusing component is 3.5 to 4.5 mm, and the effective aperture d1 = 2L1*tg(θ / 2), where θ is the field divergence angle. The surface is coated with an anti-reflection film, achieving a transmittance >99%.

[0023] This master beam focusing assembly features a compact structure, high optical path efficiency, and symmetrical and stable depth-of-focus extension, ensuring clear imaging of the patterned image at any position within the area. The use of single positive lenses, such as biconvex and plano-convex lenses, balances focusing performance with manufacturing costs. The optional design of spherical / aspherical lenses adapts to different precision requirements, with the use of aspherical lenses reducing aberrations by 25%, further optimizing focusing quality. Furthermore, the working distance and focal length of the master beam focusing assembly are limited to ensure a compact structure (overall dimensions ≤ 5mm × 5mm). Simultaneously, a transmittance of over 99% reduces laser energy loss, improving system luminous efficiency by 15% and preventing device overheating issues caused by energy loss.

[0024] A further improved solution employs a lens group consisting of two double meniscus lenses and one biconvex aspherical lens, with a focal length of 5.9mm and a working distance L2≈f2. The optical surfaces of the main ray parallelizing component are coated with a laser anti-reflection coating, achieving a transmittance of >99% for the three lenses and >97% for the combined lens. This lens group is compatible with the lens type of the main ray focusing component, ensuring optical path consistency and compatibility. The combined lens group uses a parallelism deviation of less than 1°, ensuring the symmetry of the depth-of-focus extension area. The working distance is close to the effective focal length, ensuring parallel output of the main ray. The over 97% transmittance, in conjunction with the focusing component, results in a total transmittance of ≥96% for the entire depth-of-focus extension focusing module, significantly improving laser energy utilization. The combination of the double meniscus lens and the biconvex aspherical lens provides excellent aberration correction capabilities, ensuring better focusing of rays at the edges of each field of view while maintaining parallel output of the main ray.

[0025] A further improved solution involves a pattern piece movably positioned within the depth-of-focus extension region. The depth-of-focus extension focusing module achieves a depth-of-focus extension of 4mm. Within this extended region, the pattern piece has a movement space ≥3mm, as the thickness of the thin-film homogenizing device is less than 1mm. The depth-of-focus extension region is symmetrically positioned around the focal plane, with an edge focal plane height ≤1.1H, where H is the focal plane height. By optimizing the lens curvature radius and thickness using optical design software, a depth-of-focus extension of 4mm is achieved, and the edge focal plane height H1=H2≤1.1H. This clearly defines the parameters of depth-of-focus extension, pattern piece movement space, and edge focal plane height, ensuring high-quality imaging within a movement range of ≥3mm. This solves the problem of precise pattern piece positioning (error ≤0.1mm) in existing technologies, improving installation and debugging efficiency by 50%.

[0026] Therefore, in laser system design, the principal rays and edge rays of each field of view can fully characterize the beam characteristics of the system. In the depth-of-focus extension focusing module, the beams of each field of view from the output surface of the RGB mixing device are focused by the principal ray focusing component, achieving quasi-parallel output of the principal rays of each field of view. The principal ray focusing component is at least one single positive lens, not limited to biconvex lenses, plano-convex lenses, meniscus lenses, spherical and aspherical lenses. The optical surface of the lens is coated with a laser anti-reflection film to ensure a transmittance >99%, ensuring high-efficiency laser transmission. The minimum limiting spot diameter of the principal ray focusing point is D1 = 2.44λf1 / d1 (λ is the laser wavelength, f1 is the effective focal length of the principal ray focusing component, and d1 is the effective aperture of the principal ray focusing component). The principal ray focusing point diameter is designed to be D≤20D1. Combined with the subsequent principal ray parallel component, this satisfies the telecentric optical path structure of near-parallel output of the principal rays in each field of view. By optimizing and modifying the lens curvature radius, center thickness, and refractive index of the lens glass material in this component or lens group, aberrations can be corrected, making the designed master ray focusing point diameter closer to the minimum limiting value. Furthermore, considering the more compact geometry of the master ray focusing component, the working distance L1 (the distance from the light-emitting surface of the RGB mixing device to the master ray focusing component) is generally around 1.5-3.5mm, corresponding to an effective aperture d1 = 2L1*tg(θ / 2) and an effective focal length f1 of 3.5-4.5mm.

[0027] After focusing, the principal rays of each field of view pass through a principal ray parallelizing component, ensuring that the principal rays of each field of view are output parallel to the optical axis, while the peripheral rays of each field of view are focused at the focal plane, forming a symmetrical depth-of-focus extension region. The principal ray parallelizing component is at least one single positive lens, not limited to biconvex lenses, plano-convex lenses, meniscus lenses, spherical lenses, and aspherical lenses. The lens optical surface is coated with a laser anti-reflection coating to ensure a transmittance >99%, guaranteeing high-efficiency laser transmission. The working distance L2 of the principal ray parallelizing component, i.e., the distance from the focal point of the principal ray to the component, is close to the effective focal length f2 of the component, thus achieving approximately parallel output of the principal rays of each field of view. Under the premise that the effective focal length of the component is f2, by optimizing and modifying the lens curvature radius, lens center thickness, and refractive index of the lens glass material in the component or lens group, the peripheral rays of each field of view are focused at the focal plane. The principal rays of each field of view are output parallel to the optical axis, and the peripheral rays of each field of view are focused at the focal plane, forming a symmetrical depth-of-focus extension region centered on the focal plane. The focal plane height is defined as H. When the edge focal plane height H1=H2≤1.1H, this area is the focal depth extension area. Placing a pattern piece in this area will not affect the projection quality of the pattern piece.

[0028] The laser beam, after being homogenized by an RGB mixing device, is split into multiple sub-beams with gaps. When projected through a laser projection module, beam splitting occurs in the near-field region of the laser beam (generally about 1-3 meters from the light-emitting surface of the laser projection module), severely affecting beam quality. This patented technology addresses this by using a depth-of-focus extension focusing module to focus the multiple sub-beams onto the surface of a thin-film homogenizing device. The surface of the homogenizing device is etched using techniques to create a microscopic scattering effect, expanding the divergence angle of the sub-beams and achieving beam filling and aggregation of the multiple sub-beams.

[0029] A further solution involves a thin-film homogenizing device. This device is a glass sheet with a micron-level roughened structure formed on its surface by laser etching. Its scattering angle is designed to be 5°-10°, allowing multiple focused sub-beams to diffuse and overlap after passing through, filling gaps and achieving homogenized beam combining. This effectively eliminates the near-field beam splitting problem caused by the multi-point sub-beam arrangement of RGB mixing devices, improving beam uniformity and light energy utilization.

[0030] A further advanced solution involves mounting multiple pattern pieces using a rotating mechanism driven by a stepper motor to control pattern switching. The pattern pieces are located within the depth-of-focus extension area and their axial positions can be finely adjusted to accommodate different projection requirements. This enables rapid switching between multiple patterns, and due to the depth-of-focus extension, the pattern piece positions allow for a certain degree of error, improving the system's assembly and usability.

[0031] A further advanced solution employs a telecentric optical structure in the depth-of-focus extension focusing module. By controlling the angle range of the edge rays in each field of view through ray tracing, the edge rays are focused at the focal plane. This telecentric optical structure and edge ray angle control ensure consistent beam characteristics across all fields of view, resulting in edge distortion of the projected pattern ≤3%. Compared to the 5% distortion rate of existing technologies, this significantly improves imaging accuracy, meeting the demands of high-precision projection scenarios. Furthermore, a laser projection module enables long-distance projection, and the projected beam has a small divergence angle, ensuring the outgoing beam divergence angle is less than 1°, achieving clear projection at long distances (e.g., over 100 meters).

[0032] A further advanced approach involves a microscopic scattering structure on the surface of the thin-film homogenizer, used to expand the divergence angle of the sub-beams and achieve beam combining of multiple sub-beams across gaps. This microscopic scattering structure is formed on the surface of the thin-film homogenizer through an etching process, expanding the divergence angle of the sub-beams and enabling beam combining of multiple sub-beams to fill gaps. The etched microscopic scattering structure precisely solves the sub-beam gap problem, resulting in a combined laser beam with no beam splitting in the 1-3 meter near-field region, exhibiting beam uniformity ≥95%. Compared to existing technologies, this represents a 40% improvement in near-field beam quality.

[0033] A further advanced solution involves using single pattern pieces or multiple pattern pieces with different content, mounted via a rotating mechanism. The rotating mounting design for multiple pattern pieces enables dynamic pattern switching with a response time of ≤0.1s, adapting to various scenarios such as stage projection and advertising displays, thus expanding the system's application scope.

[0034] The RGB laser projection module disclosed in this embodiment has its core components assembled in the following optical path order: RGB laser emitter (outputs a single or multiple RGB laser beams) → laser coupling device (model LC-808, light-passing aperture 18mm) → RGB mixing device (material is optical glass, light-emitting surface size 1.5mm×1.5mm) → depth-of-focus extension focusing module → thin film homogenizing device (thickness 1mm, substrate material is quartz) → pattern sheet (size 10mm×10mm, light transmittance 95%) → laser projection module (projection angle 1° to 30°).

[0035] The specific work process is as follows: S1. The RGB laser beam (wavelength range 440-680nm) emitted by the RGB laser emitter enters the laser coupling device. The device focuses the beam with a parallelism divergence angle <3° onto the input surface of the RGB mixing device by focusing, so that the size of the beam focusing surface is less than or equal to the size of the input surface of the RGB mixing device. S2. The focused laser beam enters the RGB mixing device, and the red, green and blue light are uniformly mixed through internal total internal reflection. The color uniformity deviation of the mixed beam is ≤±2%. S3. The mixed laser beam is incident on the depth-of-focus extension focusing module. First, it passes through the principal ray focusing component (using a crescent moon lens with a refractive index of 1.77, radii of curvature of -118.435mm and 3.176mm, and a center thickness of 2.2mm). The working distance of this component is L1=1.52mm, the effective focal length is f1=4.1mm, and the effective aperture is d1=2×2.5×tg(θ / 2) (θ=10°, calculated to be d1≈0.44mm). This component achieves the focusing of the principal rays in each field of view. The focal point diameter is D=5D1 (d1=2×1.52×tg(θ / 2) (θ=10°, calculated to be d1≈0.27mm), which is close to the minimum limit value, ensuring the focusing effect. S4. The focused principal ray enters the principal ray parallel assembly (a lens group consisting of two meniscus lenses and one biconvex aspherical lens, with an effective focal length f2 = 5.9mm. The first meniscus lens has a refractive index of 1.62 and radii of curvature of -51.16 and -4.51mm respectively; the second meniscus lens has a refractive index of 1.92 and radii of curvature of 19.78 and 4.55mm respectively; the biconvex aspherical lens has a refractive index of 1.85 and radii of curvature of 11.15 and -5.72mm respectively, and even-order aspherical conic coefficients are...). -0.785 and -0.041, fourth-order term coefficients are 1.89E-005 and -2.02E-005 respectively, sixth-order term coefficients are 0 and 7.56E-006, and eighth-order term coefficients are 0 and 2.71E-006, making the principal rays of each field of view approximately parallel to the optical axis, while the edge rays of each field of view focus at the focal plane, forming a symmetrical depth-of-focus extension region centered on the focal plane, with an extension of 4mm, a focal plane height H=3.6mm, and edge focal plane heights H1=H2=3.91mm (≤1.1H=3.96mm). S5. The laser beam in the focal depth extension region is incident on the thin-film homogenizing device. The surface of the device is formed with micron-level scattering protrusions (protrusion height 5μm, spacing 10μm) by ICP etching. After mixing, it is divided into multiple sub-beams with gaps (gap width ≤0.1mm). Through the action of the micro-scattering structure, the divergence angle of the sub-beams is expanded from several mrad to about 5° to 10°. The divergence regions of adjacent sub-beams overlap and fill the gaps to achieve beam merging. S6. The combined laser beam irradiates the pattern plate (three quartz plates with different patterns are installed using a rotating mechanism, with a rotation speed of 10r / min). The pattern plate is located in the depth-of-focus extension area and can move 2.5mm (≥2mm) along the optical axis. It can be clearly imaged no matter where it is located in this area. S7. The laser beam carrying the pattern information enters the laser projection module, is focused by the lens group and projected onto the pattern projection area. The divergence angle of the minimum projection beam is ≤1°, achieving projection over a distance of 100 meters.

[0036] Example embodiments have been disclosed herein, and while specific terminology has been used, it is for illustrative purposes only and should be construed as such, and is not intended to be limiting. In some instances, it will be apparent to those skilled in the art that features, characteristics, and / or elements described in conjunction with particular embodiments may be used alone, or in combination with features, characteristics, and / or elements described in conjunction with other embodiments, unless otherwise expressly indicated. Therefore, those skilled in the art will understand that various changes in form and detail may be made without departing from the scope of the invention as set forth in the appended claims.

Claims

1. A laser projection system based on depth-of-focus extension focusing, characterized in that, include: The RGB laser beam, laser coupling device, RGB mixing device, depth-of-focus extension focusing module, thin-film homogenizing device, pattern sheet and laser projection module are arranged sequentially along the optical path; The RGB laser beam enters the RGB mixing device through the laser coupling device to achieve three-color mixing. The mixed laser beam is then extended and focused by the depth-of-focus extension and focusing module, and then homogenized and mixed by the thin-film homogenizing device. Finally, the content of the pattern sheet is projected onto the pattern projection area through the laser projection module to achieve long-distance projection.

2. The system according to claim 1, characterized in that, The depth-of-focus extension focusing module includes: The main ray focusing component is used to focus the main rays of each field of view from the light-emitting surface of the RGB mixing device; The principal ray parallel component is used to adjust the principal rays of each field of view after focusing to be parallel to the optical axis and to focus the edge rays of each field of view at the focal plane, forming a symmetrical depth-of-focus extension area centered on the focal plane.

3. The system according to claim 2, characterized in that, The master beam focusing component includes at least one single positive lens, selected from one of a biconvex lens, a plano-convex lens, a meniscus lens, a cemented lens, and an aspherical lens; the optical surface of the master beam focusing component is coated with a laser anti-reflection film with a transmittance >99%.

4. The system according to claim 3, characterized in that, The working distance L1 of the main ray focusing component is 1.5 to 3.5 mm, and the working distance L1 is the distance from the light-emitting surface of the RGB mixing device to the main ray focusing component; the effective focal length f1 of the main ray focusing component is 3.5 to 4.5 mm, and the effective light-transmitting aperture d1 = 2L1*tg(θ / 2), where θ is the field divergence angle.

5. The system according to claim 2, characterized in that, The main ray parallel component includes at least one single positive lens, selected from biconvex lenses, plano-convex lenses, meniscus lenses, cemented lenses, and aspherical lenses, with its optical surface coated with a laser anti-reflection coating.

6. The system according to claim 2, characterized in that, The working distance L2 of the main ray parallel component is its own effective focal length f2. The working distance L2 is the distance from the main ray focusing point to the main ray parallel component. The optical surface of the main ray parallel component is coated with a laser anti-reflection film with a transmittance >99%.

7. The system according to claim 1, characterized in that, The surface of the thin-film homogenizing device is etched to form a microscopic scattering structure, which is used to expand the divergence angle of the sub-beams and realize the beam combining of multiple sub-beams to fill the gaps.

8. The system according to claim 1, characterized in that, The pattern piece is movably disposed within the depth-of-focus extension region. The depth-of-focus extension focusing module achieves a depth-of-focus extension of 4 mm. Within the formed depth-of-focus extension region, the movement space of the pattern piece is ≥3 mm. The depth-of-focus extension region is symmetrically arranged with the focal plane as the center, and the edge focal plane height is ≤1.1H, where H is the focal plane height.

9. The system according to claim 1, characterized in that, The depth-of-focus extension focusing module is a telecentric optical structure that controls the angle range of light rays at the edge of each field of view through ray tracing, so that the light rays at the edge of each field of view are focused at the focal plane.

10. The system according to claim 1, characterized in that, The pattern piece can be a single piece or multiple pattern pieces with different contents installed by a rotating mechanism.

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