Collimation system with light recovery function

Abstract

The embodiment of the invention provides a collimation system with a light recovery function, and relates to the technical field of optics. The collimation system with the light recovery function sequentially comprises a first lens, a second lens and a third lens from an object side to an image side along an optical axis, the second lens is provided with a first object side surface and a first image side surface, the first object side surface is a plane lens surface, and the first image side surface is a curved surface with degree of freedom design; the third lens is provided with a second object side surface and a second image side surface, the second object side surface is a curved surface with degree of freedom design, and the second image side surface is a plane lens surface; a reflecting mirror is arranged behind a partial region of the second image side surface; wherein the collimation system comprises two light paths: light of the first light path is collimated and output to a receiving end after being transmitted by a first lens, a second lens and a third lens in sequence; and the light of the second light path is sequentially collimated by the first lens, the second lens and the third lens, reflected by the reflector and returned to the surface of the light source along the original path. High-efficiency light recovery can be realized.

Description

Technical Field

[0001] This invention relates to the field of optical technology, and more specifically, to a collimation system with light recovery function. Background Technology

[0002] In modern optical applications such as optical measurement, lidar, fiber optic communication, and precision sensing, it is often necessary to convert divergent beams emitted by light sources (such as laser diodes and light-emitting diodes) into collimated or focused beams for transmission and utilization. The performance of the collimation system, such as collimation accuracy, spot quality, and energy efficiency, directly determines the accuracy and efficiency of the entire optical system.

[0003] Traditional collimation systems typically use a combination of one or more lenses to achieve beam collimation and focusing. However, such systems suffer from a common problem: not all the light emitted by the light source can be effectively utilized. Some light rays, due to aberrations, assembly errors, or design limitations, deviate from the main optical path, forming stray light or resulting in energy loss that cannot be collected by the receiver, thus reducing the system's light energy utilization efficiency. Summary of the Invention

[0004] This invention provides a collimation system with light recovery function, which can achieve efficient light recovery, improve light energy utilization efficiency, and reduce energy loss.

[0005] The embodiments of the present invention can be implemented as follows: Embodiments of the present invention provide a collimation system with light recovery function, comprising: Along the optical axis from the object side to the image side, it includes, in sequence, a first lens, a second lens, and a third lens, wherein the first lens, the second lens, and the third lens are spaced apart from each other; The first lens is a spherical lens, which is used to initially focus the diverging light emitted by the light source; The second lens has a first object-side surface and a first image-side surface. The first object-side surface is a planar lens surface, and the first image-side surface is a curved surface with a degree of freedom of design. The third lens has a second object-side surface and a second image-side surface. The second object-side surface is a curved surface with a degree of freedom in design, and the second image-side surface is a planar lens surface. A reflecting mirror is disposed behind a portion of the second image-side surface. The collimation system includes two optical paths: The first optical path, in which the light rays pass through the first lens, the second lens and the third lens in sequence, and are then collimated and output to the receiving end; The second optical path, after being collimated by the first lens, the second lens and the third lens in sequence, is reflected by the mirror and returns to the surface of the light source along the original path.

[0006] In an optional implementation, the first image-side surface and the second object-side surface are designed using optical algorithms so that the light path can return to the surface of the light source along the original path after being reflected by the mirror.

[0007] In an optional implementation, the optical algorithm design principle includes: establishing a rectangular coordinate system with the light source as the starting coordinate point; the light from the light source passes through the inner surface I point of the first lens, is refracted and incident on the first object-side surface J point of the second lens, is deflected inside the second lens to the first image-side surface K point, and is then refracted to the second object-side surface L point of the third lens. Since the first lens is a spherical lens, the coordinates of point I can be obtained according to the spherical coordinate formula; By applying the partial derivative formula for the equation of a two-dimensional circle and substituting the coordinates of point I, we obtain the equations of the corresponding tangent line and normal line, thus yielding the normal vector. ; Then, according to Fresnel's law, we can derive... Thus, the equation of line IJ is obtained; the coordinates of point J are determined based on the equation of line IJ. Similarly, according to Fresnel's law, we can derive... and And obtain the equations of the tangents at points K and L.

[0008] In an optional implementation, obtaining the coordinates of point I according to the spherical coordinate formula includes: according to the formula:

[0009] The coordinates of point I are obtained; where the radius r and the initial divergence angle θ are known quantities, determined by the first lens.

[0010] In an optional implementation, the normal vector is obtained by substituting the partial derivative of the equation of a two-dimensional circle into the coordinates of point I to obtain the corresponding tangent equation and normal equation. Specifically: according to , The equation of the tangent line is derived as follows: ; And the equation of the normal line: .

[0011] In an optional implementation, the statement derived from Fresnel's law... Thus, the equation of line IJ is obtained; based on the equation of line IJ, the coordinates of the corresponding point J are specifically as follows: According to Fresnel's law: ; Simplifying the above equation yields And the equation of line IJ: ; The equation of the straight line IJ is: ; The coordinates of point J are obtained from the equation of line IJ; Where n0 is the refractive index of air and n1 is the refractive index of the first lens.

[0012] In an optional implementation, the statement derived from Fresnel's law... and And the equations of the tangents at points K and L are obtained as follows: According to the formula: , and thus ; According to the formula: , and thus ; Simplifying the two equations above, we obtain the equations of the tangent lines at points K and L: ; Where n0 is the refractive index of air and n2 is the refractive index of the second lens.

[0013] In an optional implementation, the optical algorithm design principle further includes: using Euler's formula to calculate the corresponding iterative coordinate points of the discrete trajectories on the first image-side surface and the second object-side surface based on the initial point.

[0014] In an optional embodiment, after the second light path is refracted to point L, it is refracted inside the third lens to point E on the second image side. After being collimated and emitted, it is reflected back to the surface of the light source along the original path by the mirror.

[0015] In an optional implementation, the first optical path is collimated to the receiving end via a variable aperture.

[0016] The beneficial effects of the collimation system with light recovery function in this embodiment of the invention include, for example: This collimation system with light recovery function comprises, along the optical axis from the object side to the image side, a first lens, a second lens, and a third lens, which are spaced apart from each other. The first lens is a spherical lens used for initial focusing of the diverging light emitted from the light source. The second lens has a first object-side surface and a first image-side surface; the first object-side surface is a planar lens surface, and the first image-side surface is a curved surface with degrees of freedom. The third lens has a second object-side surface and a second image-side surface; the second object-side surface is a curved surface with degrees of freedom, and the second image-side surface is a planar lens surface. A reflector is positioned behind a portion of the second image-side surface. The collimation system includes two optical paths: the light in the first optical path is transmitted through the first, second, and third lenses sequentially and then collimated before being output to the receiving end; the light in the second optical path is collimated through the first, second, and third lenses sequentially, reflected by the reflector, and returns to the surface of the light source along its original path. Through ingenious design and optimized optical structure, this collimation system achieves efficient light recovery, improves light energy utilization efficiency, and reduces energy loss. Meanwhile, the compact three-piece structure not only facilitates integration and installation, but also effectively reduces manufacturing costs and system complexity, meeting the demands of modern optical applications for miniaturization and high efficiency. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of a collimation system with light recovery function provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the optical algorithm design principle of the entire collimation system provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the first optical path optical algorithm design provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the design principle of the second optical path optical algorithm provided in an embodiment of the present invention.

[0019] Icons: 1000 - Collimation system with light recovery function; 100 - First lens; 200 - Second lens; 210 - First object side; 220 - First image side; 300 - Third lens; 310 - Second object side; 320 - Second image side; 400 - Reflector; 500 - Receiver; 600 - Light source; 1 - First optical path; 2 - Second optical path. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0021] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0022] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0023] In the description of this invention, it should be noted that if terms such as "upper," "lower," "inner," or "outer" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this invention is usually placed, they are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0024] Furthermore, the terms "first" and "second" are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0025] It should be noted that, where there is no conflict, the features in the embodiments of the present invention can be combined with each other.

[0026] In modern optical applications such as optical measurement, lidar, fiber optic communication, and precision sensing, it is often necessary to convert diverging beams emitted by light sources (such as laser diodes and light-emitting diodes) into collimated or focused beams for transmission and utilization. The performance of the collimation system, such as collimation accuracy, spot quality, and energy utilization rate, directly determines the accuracy and efficiency of the entire optical system. Traditional collimation systems typically use a combination of one or more lenses to achieve beam collimation and focusing. However, such systems have a common problem: not all the light emitted by the light source can be effectively utilized. Some light rays, due to aberrations, assembly errors, or design limitations, deviate from the main optical path, forming stray light or resulting in energy loss that cannot be collected by the receiver, leading to a reduction in the system's light energy utilization efficiency.

[0027] In modern optical systems, light energy utilization efficiency is one of the key indicators for evaluating their performance. However, traditional optical systems generally face the problem of light loss, especially in fields such as precision optics, lasers, optical communication, and photoelectric detection. Light recovery technology is an important solution to this problem. Its core idea is to collect and utilize light that has not been effectively utilized due to scattering, absorption, or escape. By introducing mirrors, diffuse reflection cavities, or special optical structures, the light that was originally lost can be redirected back to the working area or light source, thereby significantly improving light output efficiency, brightness uniformity, and energy conversion efficiency. Currently, similar light recovery concepts have been validated in multiple applications. For example, in LCD light guide plates and micro-projection optical engines, microprisms or reflective sheets are often embedded to "reflect" light leaking from the panel edges back to the effective display area; in laser processing or laser amplification links, a dual-zone structure of "cutting area + recovery area" is used to send laser light that has not been absorbed by the material back to the gain medium through mirrors, achieving secondary amplification. Nevertheless, existing technologies still generally suffer from problems such as large system size, complex structure, and limited improvement in light energy utilization.

[0028] Based on this, please refer to Figure 1 and Figure 2 The collimation system 1000 with light recovery function provided in the embodiments of the present invention can effectively improve the aforementioned technical problems. This collimation system 1000 with light recovery function can achieve efficient light recovery, improve light energy utilization efficiency, and reduce energy loss. Furthermore, it has a simple structure, is easy to integrate and install, and can reduce manufacturing costs and system complexity, meeting the demands of modern optical applications for miniaturization and high efficiency.

[0029] Figure 1 This is a schematic diagram of a collimation system 1000 with light recovery function provided in an embodiment of the present invention; Figure 2 This is a schematic diagram illustrating the optical algorithm design principle of the entire collimation system provided in an embodiment of the present invention. Figure 1 and Figure 2As shown, the collimation system 1000 with light recovery function in this embodiment includes, along the optical axis from the object side to the image side: a first lens 100, a second lens 200, and a third lens 300, which are spaced apart from each other. The first lens 100 is a spherical lens, used for preliminary focusing of the diverging light emitted by the light source 600. The second lens 200 has a first object-side surface 210 and a first image-side surface 220. The first object-side surface 210 is a planar lens surface, and the first image-side surface 220 is a curved surface with degrees of freedom. The third lens 300 has... The system comprises a second object-side surface 310 and a second image-side surface 320. The second object-side surface 310 is a curved surface with a degree of freedom in its design, while the second image-side surface 320 is a planar lens surface. A reflecting mirror 400 is positioned behind a portion of the second image-side surface 320. The collimation system includes two optical paths: light rays from the first optical path 1 are transmitted sequentially through the first lens 100, the second lens 200, and the third lens 300 before being collimated and output to the receiving end 500; light rays from the second optical path 2 are collimated sequentially through the first lens 100, the second lens 200, and the third lens 300, then reflected by the reflecting mirror 400 and returning along their original path to the surface of the light source 600. Through ingenious design and optimized optical structure, this collimation system achieves efficient light recovery, improves light energy utilization efficiency, and reduces energy loss. Furthermore, the compact three-piece structure not only facilitates integration and installation but also effectively reduces manufacturing costs and system complexity, meeting the demands of modern optical applications for miniaturization and high efficiency.

[0030] The object side mentioned above refers to the surface of the lens facing the light source at a 60° angle; the image side refers to the surface of the lens facing the imaging direction.

[0031] In use, the light source 600 is placed on the side of the first lens 100 away from the second lens 200. In this embodiment, the light source 600 is an LED. This collimation system is suitable for LED chips of any wavelength, and is especially suitable for high power density LED applications. Light emitted from the surface of the LED chip is reflected by the designed collimation module and returns to the surface of the LED chip along its original path. Because the surface of the LED chip is relatively flat and has a certain scattering rate, the re-reflected light will be superimposed with the newly emitted light in the same phase space. The reduction in phase space results in an increase in power density.

[0032] Neglecting system and Fresnel losses, the light rays from both the first optical path 1 and the second optical path 2 will eventually reach the target illumination area. Therefore, algorithmic design is necessary for the second lens 200 and the third lens 300 in the system to achieve an integrated collimation system 1000 with light recovery function. Since the second optical path 2 must have sufficient collimation to ensure that the light rays return to the light source 600 along the original path after being reflected by the mirror 400, the compact three-element lens design can be considered as a whole for algorithmic design. In summary, through optical algorithm design, the first image-side surface 220 and the second object-side surface 310 in this embodiment enable the light rays to return to the surface of the light source 600 along the original path after being reflected by the mirror 400.

[0033] Figure 3 This is a schematic diagram illustrating the optical algorithm design principle of the first optical path 1 provided in an embodiment of the present invention. Please refer to [link / reference]. Figure 3 and combined Figure 2 In this embodiment, the first optical path 1 is based on geometric optics, the law of conservation of energy, and Fresnel's law, establishing a Cartesian coordinate system. The LED light source 600 is located at point O. The LED light is refracted at point I on the inner surface of the first lens 100 and then incident on point 210 on the first object-side surface of the second lens 200. After being deflected inside the second lens 200, it is refracted to point 220 on the first image-side surface, and then refracted again to point 310 on the second object-side surface of the third lens 300, finally collimating and incident on the receiving surface. The incident light... Transmitted light is formed after refraction by the inner surface of the first lens 100. The normal vector is The tangent vector is Then transmitted light The incident light, after being refracted again at the inner surface of the second lens 200, forms transmitted light. Deflected to the outer surface, the normal vector is The tangent vector is Then transmitted light After refraction, transmitted light is formed. The normal vector is The tangent vector is Finally, it is deflected by the inner surface of the third lens 300. The light is collimated and incident on a plane 500° from the receiver, with a normal vector of... The tangent vector is .

[0034] Figure 4 This is a schematic diagram illustrating the design principle of the second optical path 2 optical algorithm provided in an embodiment of the present invention. Please refer to [link / reference]. Figure 4 and combined Figure 2Similarly, in this embodiment, the second optical path 2 is based on geometric optics, the law of conservation of energy, and Fresnel's law, establishing a rectangular coordinate system. The LED light source 600 is located at point O. The LED light is refracted at point A on the inner surface of the first lens 100 and then incident on the first object-side surface 210 of the second lens 200. After being deflected inside the second lens 200, it is incident on the first image-side surface 220, and then refracted to the second object-side surface 310 of the third lens 300. It is then collimated to the reflecting mirror 400 and returns to point O along the same path, forming the entire light recovery function. The incident light... Transmitted light is formed after refraction by the inner surface of the first lens 100. The normal vector is The tangent vector is Then transmitted light The incident light, refracted again by the second lens 200, forms transmitted light. Deflected to the outer surface, the normal vector is The tangent vector is Then transmitted light After refraction, transmitted light is formed. The normal vector is The tangent vector is Finally, it is deflected by the inner surface of the third lens 300. The collimated incident mirror returns to point O via the original path at point 400, with the normal vector being... The tangent vector is .

[0035] Specifically, the optical algorithm design principle in this embodiment includes: establishing a rectangular coordinate system with the light source 600 as the starting coordinate point O; the light from the light source 600 passes through the inner surface I of the first lens 100, is refracted and incident on the first object side surface 210 of the second lens 200, is deflected inside the second lens 200 to the first image side surface 220, and then refracted to the second object side surface 310 of the third lens 300. Since the first lens 100 is a spherical lens, the coordinates of point I can be obtained according to the spherical coordinate formula. The coordinates of point I, derived from the spherical coordinate formula, include: (Based on the formula:)

[0036] The coordinates of point I are obtained; where the radius r and the initial divergence angle θ are known quantities, determined by the first lens 100.

[0037] By applying the partial derivative formula for the equation of a two-dimensional circle and substituting the coordinates of point I, we obtain the equations of the corresponding tangent line and normal line, thus yielding the normal vector. ; By applying the partial derivative formula for the equation of a two-dimensional circle and substituting the coordinates of point I, we obtain the equations of the corresponding tangent line and normal line, thus yielding the normal vector. Specifically: according to , The equation of the tangent line is derived as follows: ; And the equation of the normal line: .

[0038] Then, according to Fresnel's law, we can derive... Thus, the equation of line IJ is obtained; the coordinates of point J are determined based on the equation of line IJ. According to Fresnel's law, Thus, the equation of line IJ is obtained; based on the equation of line IJ, the coordinates of the corresponding point J are specifically as follows: According to Fresnel's law: ; Simplifying the above equation yields And the equation of line IJ: ; The equation of the straight line IJ is: ; The coordinates of point J are obtained from the equation of line IJ; Where n0 is the refractive index of air and n1 is the refractive index of the first lens 100.

[0039] Similarly, according to Fresnel's law, we can derive... and And obtain the equations of the tangents at points K and L.

[0040] According to Fresnel's law, and And the equations of the tangents at points K and L are obtained as follows: According to the formula: , and thus ; According to the formula: , and thus ; Simplifying the two equations above, we obtain the equations of the tangent lines at points K and L: ; Where n0 is the refractive index of air and n2 is the refractive index of the second lens 200.

[0041] The algorithm for point 2 of the second optical path is the same as the algorithm for point 1 of the first optical path. The algorithm for point 2 of the second optical path is the same as the algorithm for point 1 of the first optical path. The algorithm for point 2 of the second optical path is the same as the algorithm for point 1 of the first optical path. The algorithm for point 2 of the second optical path is the same as the algorithm for point 1 of the first optical path. All of them are obtained by using the above-mentioned optical algorithm design principle.

[0042] In this embodiment, after the second optical path 2 is refracted to point L, it is refracted inside the third lens 300 to point 320 on the side of the second image. After being collimated and emitted, it is reflected back to the surface of the light source 600 along the original path by the reflector 400. ,Right now The algorithm and the result derived from Fresnel's law and The algorithm for obtaining the tangent equations at points K and L is the same, and will not be repeated here.

[0043] Furthermore, the optical algorithm design principle in this embodiment also includes: using Euler's formula to calculate the corresponding iterative coordinate points of the discrete trajectories on the first image side 220 and the second object side 310 based on the initial point. This yields the designed second lens 200 and third lens 300, ensuring that the light rays from the second optical path 2 are collimated sequentially by the first lens 100, the second lens 200, and the third lens 300, and then reflected by the mirror 400, returning along the original path to the surface of the light source 600, thus ensuring that the entire collimation system has a light recovery function.

[0044] Optionally, in this embodiment, the first optical path 1 is collimated and output to the receiver 500 via a variable aperture. The variable aperture is essentially an adjustable aperture stop. By changing the opening and closing size of the aperture, the portion of the collimated beam with lower energy and poorer light quality (such as larger aberrations or larger angles) at the edge can be physically trimmed. This allows for the direct output of a collimated beam of a specified diameter without replacing the entire optical system.

[0045] This collimation system allows for the design of second lens 200 and third lens 300 with different degrees of freedom based on the refractive index of different lenses. The specific design is determined by the actual application and is not limited here. After trimming away stray light from the edges, the output beam is closer to ideal parallel light, with a smaller beam divergence angle, better uniformity, and improved beam quality. Different optical receiving devices have different requirements for the size and energy density of the input light spot. The first optical path 1 outputs to the receiver 500 through variable aperture collimation, flexibly adapting to the needs of different receivers 500.

[0046] This invention achieves the following beneficial effects by introducing a light recovery device and lens co-designed structure into the optical system: By introducing a light recovery device at the rear end of the lens, the originally scattered or escaping light is guided back to the emitting surface and emitted again by specular reflection, thereby significantly improving the light energy utilization efficiency. Actual processing and testing have verified that, under the conditions of 385 nm wavelength and 15 mm output aperture, the measured far-field power density is increased by 47.5% compared to the system without light recovery. Through optical path folding and secondary utilization, the energy distribution of the far-field spot is improved, enhancing the uniformity of the light field, while reducing the need for over-driving the light source 600, thus helping to extend the lifespan of the light source 600. Since light energy reuse replaces the method of simply increasing the number or power of the light source 600, high energy efficiency output can be achieved within a limited volume, which is beneficial for the miniaturization design of the system. The light recovery device in this solution has strong adaptability, maintaining the power density enhancement effect even with changes in the output aperture. Although the proportion of the reflection area decreases under large aperture conditions, the overall performance is still superior to the structure without light recovery. This invention, through the overall structural design of the lens light recovery device, not only significantly improves the efficiency of light energy utilization, but also brings a series of advantages such as improved light field uniformity, extended light source lifespan (600), and reduced system size. Overall, it has significant practical value and promotional significance.

[0047] In summary, the collimation system 1000 with light recovery function includes, along the optical axis from the object side to the image side, a first lens 100, a second lens 200, and a third lens 300, which are spaced apart from each other. The first lens 100 is a spherical lens, used for preliminary focusing of the diverging light emitted by the light source 600. The second lens 200 has a first object-side surface 210 and a first image-side surface 220. The first object-side surface 210 is a planar lens surface, and the first image-side surface 220 is a curved surface with degrees of freedom. The third lens 300 has... The second object side surface 310 and the second image side surface 320 are separate entities. The second object side surface 310 is a curved surface with a degree of freedom in its design, while the second image side surface 320 is a planar lens surface. A reflector 400 is positioned behind a portion of the second image side surface 320. The collimation system includes two optical paths: light rays from the first optical path 1 are transmitted sequentially through the first lens 100, the second lens 200, and the third lens 300 before being collimated and output to the receiving end 500; light rays from the second optical path 2 are collimated sequentially through the first lens 100, the second lens 200, and the third lens 300, then reflected by the reflector 400 and return along their original path to the surface of the light source 600. Through ingenious design and optimized optical structure, this collimation system achieves efficient light recovery, improves light energy utilization efficiency, and reduces energy loss. Furthermore, the compact three-piece structure not only facilitates integration and installation but also effectively reduces manufacturing costs and system complexity, meeting the demands of modern optical applications for miniaturization and high efficiency.

[0048] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A collimation system with light recovery function, characterized in that, Along the optical axis from the object side to the image side, it includes, in sequence, a first lens (100), a second lens (200), and a third lens (300), wherein the first lens (100), the second lens (200), and the third lens (300) are arranged at intervals from each other; The first lens (100) is a spherical lens, and the first lens (100) is used to initially focus the diverging light emitted by the light source (600); The second lens (200) has a first object-side surface (210) and a first image-side surface (220), wherein the first object-side surface (210) is a planar lens surface and the first image-side surface (220) is a curved surface with degrees of freedom design; The third lens (300) has a second object-side surface (310) and a second image-side surface (320). The second object-side surface (310) is a curved surface with a degree of freedom of design, and the second image-side surface (320) is a planar lens surface. A reflecting mirror (400) is disposed behind a portion of the second image-side surface (320). The collimation system includes two optical paths: The light from the first optical path (1) is transmitted through the first lens (100), the second lens (200) and the third lens (300) in sequence, and then collimated and output to the receiving end (500). The second optical path (2) is collimated by the first lens (100), the second lens (200) and the third lens (300) in sequence, and then reflected by the mirror (400) and returned to the surface of the light source (600) along the original path.

2. The collimation system with light recovery function according to claim 1, characterized in that, The first image side (220) and the second object side (310) are designed by optical algorithms so that the light path can return to the surface of the light source (600) along the original path after being reflected by the mirror (400).

3. The collimation system with light recovery function according to claim 2, characterized in that, The optical algorithm design principle includes: establishing a rectangular coordinate system with the light source (600) as the starting coordinate point; the light from the light source (600) passes through the inner surface I point of the first lens (100), is refracted and incident on the first object side surface (210) J point of the second lens (200), is deflected inside the second lens (200) to the first image side surface (220) K point, and is then refracted to the second object side surface (310) L point of the third lens (300); Since the first lens (100) is a spherical lens, the coordinates of point I can be obtained according to the spherical coordinate formula; By applying the partial derivative formula for the equation of a two-dimensional circle and substituting the coordinates of point I, we obtain the equations of the corresponding tangent line and normal line, thus yielding the normal vector. ; Then, according to Fresnel's law, we can derive... Thus, the equation of line IJ is obtained; the coordinates of point J are determined based on the equation of line IJ. Similarly, according to Fresnel's law, we can derive... and And obtain the equations of the tangents at points K and L.

4. The collimation system with light recovery function according to claim 3, characterized in that, The method for obtaining the coordinates of point I based on the spherical coordinate formula includes: according to the formula: The coordinates of point I are obtained; where the radius r and the initial divergence angle θ are known quantities, determined by the first lens (100).

5. The collimation system with light recovery function according to claim 3, characterized in that, The method involves using the partial derivative formula of the equation of a two-dimensional circle and substituting the coordinates of point I to obtain the corresponding tangent line equation and normal line equation, thereby obtaining the normal vector. Specifically: according to , The equation of the tangent line is derived as follows: ; And the equation of the normal line: .

6. The collimation system with light recovery function according to claim 3, characterized in that, The above is derived from Fresnel's law. Thus, the equation of line IJ is obtained; based on the equation of line IJ, the coordinates of the corresponding point J are specifically as follows: According to Fresnel's law: ; Simplifying the above equation yields And the equation of line IJ: ； The equation of the straight line IJ is: ; The coordinates of point J are obtained from the equation of line IJ; Where n0 is the refractive index of air and n1 is the refractive index of the first lens (100).

7. The collimation system with light recovery function according to claim 3, characterized in that, The above is derived from Fresnel's law. and And the equations of the tangents at points K and L are obtained as follows: According to the formula: , and thus ; According to the formula: , and thus ; Simplifying the two equations above, we obtain the equations of the tangent lines at points K and L: ； Where n0 is the refractive index of air and n2 is the refractive index of the second lens (200).

8. The collimation system with light recovery function according to any one of claims 3-7, characterized in that, The optical algorithm design principle also includes: using Euler's formula to calculate the corresponding iterative coordinate points of the discrete trajectories on the first image side surface (220) and the second object side surface (310) based on the initial point.

9. The collimation system with light recovery function according to claim 2, characterized in that, After the second light path (2) is refracted to point L, it is refracted inside the third lens (300) to point E on the second image side (320). After being collimated and emitted, it is reflected back to the surface of the light source (600) along the original path by the mirror (400).

10. The collimation system with light recovery function according to claim 1, characterized in that, The first optical path (1) is collimated and output to the receiving end (500) through a variable aperture.

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