A design method and device for a polarizing lens of an LED street lamp based on free-form surface optics

Abstract

This invention relates to the field of road lighting optical design technology, specifically to a method and apparatus for designing LED streetlight polarizing lenses based on freeform surface optics. The method includes: acquiring actual LED light distribution data, target illumination surface data, road polarization control data, and lens design constraint data; establishing a light energy mapping relationship between the LED emitted light energy and the target illumination area; performing directional polarization correction based on the road polarization control data to generate an asymmetric target mapping relationship; calculating the optical refraction relationship at various positions on the lens surface based on this mapping relationship and constraint data to generate freeform surface shape data; evaluating illuminance against the surface shape data and comparing it with the target, providing feedback compensation mapping and iteratively updating the surface shape until termination conditions are met; and outputting freeform surface polarizing lens design data that meets the conditions. This invention can improve the light energy utilization rate and illuminance uniformity in road areas and reduce light energy waste in non-target areas.

Description

Technical Field

[0001] This invention relates to the field of road lighting optical design technology, and in particular to a design method and device for LED streetlight polarizing lenses based on freeform surface optics. Background Technology

[0002] Currently, LED road lighting has become mainstream. To achieve batwing light distribution curves and rectangular light spots that meet road lighting standards, secondary optical lenses are usually installed in front of the LED light source. Existing lens design methods mainly fall into three categories: First, the geometric construction method, which relies on the experience of optical engineers to manually adjust the lens profile and repeatedly simulate it. This method has a long design cycle and the results vary from person to person. Second, the partial differential equation method, which constructs free-form surfaces by solving the Monge-Ampère equation or the optimal transmission problem. This method is theoretically sound but computationally complex and difficult to implement numerically, making it difficult for ordinary engineers to master. Third, the energy mapping iteration method, which divides the solid angle of the light source equally and uses Snell's law to calculate the lens generatrix point by point. Although this method is computationally simple and easy to program, its current implementation has obvious defects. Specifically, traditional methods typically employ simple discrete mapping, failing to consider the nonlinear variations in the actual light distribution curve of the light source, resulting in illuminance distribution errors on the target surface exceeding 15%. Furthermore, existing algorithms are all open-loop unidirectional iterative, where initial mapping deviations accumulate during iterations, ultimately distorting the lens generatrix. Regarding polarization control, current designs only achieve this by simply translating the target light spot, failing to finely allocate light energy according to the actual needs of the road surface. In addition, traditional planar projection methods use a fixed step size, which easily produces step-like abrupt changes in large-angle regions, increasing the difficulty of mold manufacturing. Therefore, there is an urgent need for a polarizing lens design method that incorporates a feedback compensation mechanism, is based on rigorous integral mapping, and possesses adaptive step size and composite polarization control capabilities. Summary of the Invention

[0003] This invention aims to address at least the technical problems existing in the prior art, such as the reliance on manual experience in the design process of LED streetlight polarizing lenses, insufficient accuracy of target light spot mapping, coarse polarization control methods, and difficulty in correcting illuminance errors due to open-loop calculations. This invention provides a design method and apparatus for LED streetlight polarizing lenses based on freeform surface optics. It can jointly process the actual light distribution data of the LED light source, target illumination surface data, road polarization control data, and lens design constraint data to obtain freeform surface polarizing lens design data that meets the road polarization lighting requirements. During the lens design process, a light energy mapping relationship between the emitted light energy and the target illumination area can be established based on the actual light distribution data of the LED light source. Road polarization correction is performed on the target mapping position according to the road polarization control data, and feedback compensation is applied to the asymmetric target mapping relationship through illuminance evaluation results. This achieves iterative updates of the freeform surface shape data, thereby improving the light energy utilization rate and illuminance uniformity in the road area, reducing light energy waste on the sidewalk side and in areas outside the road, and achieving the technical effect of improving the design accuracy and stability of LED streetlight polarizing lenses.

[0004] In a first aspect, embodiments of the present invention provide a method for designing a polarizing lens for LED streetlights based on freeform surface optics, the method comprising:

[0005] S1. Obtain actual light distribution data, target illumination surface data, road polarization control data, and lens design constraint data of the LED light source. The target illumination surface data includes the target illumination area and target illuminance distribution. The lens design constraint data includes the refractive index of the lens material and the initial position data of the lens. S2. Based on the actual light distribution data and the target illumination surface data, establish a light energy mapping relationship between the light energy emitted by the LED light source and the target illumination area; S3. Based on the road polarization control data, the target mapping position in the light energy mapping relationship is corrected for road direction polarization to generate an asymmetric target mapping relationship; S4. Based on the asymmetric target mapping relationship and the lens design constraint data, determine the optical refraction relationship at each design position on the lens surface, and generate freeform surface shape data according to the optical refraction relationship; S5. Perform illuminance evaluation processing on the freeform surface shape data to obtain the actual illuminance distribution of the target illumination surface. Based on the difference between the actual illuminance distribution and the target illuminance distribution, perform feedback compensation on the asymmetric target mapping relationship. Update the freeform surface shape data based on the asymmetric target mapping relationship after feedback compensation until the preset design termination condition is met. S6. Output the design data of the freeform polarizing lens that meets the preset design termination conditions.

[0006] Optionally, S2 includes: A design coordinate system is established to describe the LED light source, the target lighting surface, and the lens surface, with the road extension direction as the road direction, the direction perpendicular to the road direction as the lateral direction, and the direction perpendicular to the target lighting surface as the height direction. The coordinate range of the target lighting area is determined based on the position of the LED light source, the range of the target lighting area in the road direction, and the range of the target lighting area in the lateral direction. The emission space of the LED light source is divided into multiple emission areas according to the emission angle and azimuth direction; Establish the correspondence between each emission area and the target mapping position in the target illumination area to obtain the light energy mapping relationship.

[0007] Optionally, S2 includes: Using the actual light distribution data of the LED light source and the emission angle range corresponding to each emission area as input, the light intensity value corresponding to each emission angle sampling position is obtained; According to the solid angle weight corresponding to each emission angle sampling position, the light intensity value in the current emission area is weighted and accumulated to obtain the cumulative emitted light energy corresponding to the current emission area. According to the solid angle weight corresponding to each emission angle sampling position, the light intensity value of the LED light source in the entire emission area is weighted and accumulated to obtain the total emitted light energy. The ratio of the cumulative emitted light energy corresponding to the current emission area to the total emitted light energy is processed to obtain the light energy distribution ratio corresponding to the current emission area. The target mapping position of the current emission area in the target illumination area is determined based on the light energy distribution ratio.

[0008] Optionally, determining the target mapping position in the light energy mapping relationship includes: Using the light energy distribution ratio in the light energy mapping relationship, the range of the target illumination area in the road direction, and the range of the target illumination area in the lateral direction as inputs, the radial mapping position corresponding to the current emission area is determined. Based on the radial mapping position and the range of the target lighting area in the road direction, determine the road direction coordinates of the target mapping position; Based on the radial mapping position, the range of the target illumination area in the lateral direction, and the azimuth position corresponding to the current emission area, the lateral coordinates of the target mapping position are determined. By combining the road direction coordinates, the lateral direction coordinates, and the position of the target illumination surface, the target mapping position corresponding to the current emission area is obtained.

[0009] Optionally, S3 includes: Using the light energy allocation ratio, maximum polarization data, polarization growth control data and mid-range polarization compensation data in the light energy mapping relationship as input, the light energy allocation ratio is mapped to a first offset component that increases as the light energy allocation ratio increases. Based on the mid-range polarization compensation data, the light energy distribution ratio is subjected to quadratic order offset compensation processing to obtain the second offset component. The first offset component and the second offset component are superimposed, and the superposition result is used as the polarization offset corresponding to the current target mapping position; The coordinates of the current target mapping position in the road direction are corrected using the polarization offset to obtain the corresponding asymmetric target mapping position; The asymmetric target mapping relationship is generated based on the mapping positions of each asymmetric target.

[0010] Optionally, S4 includes: Using the position of the LED light source and the current lens design position as input, determine the direction of incident light from the LED light source to the current lens design position; Using the current lens design position and the corresponding asymmetric target mapping position as input, determine the direction of the emitted light from the current lens design position to the asymmetric target mapping position; The incident light direction is weighted according to the refractive index of the lens material, and the direction difference between the weighted incident light direction and the outgoing light direction is processed to obtain the normal vector direction of the current lens design position. The normal vector direction is normalized to obtain the surface normal vector of the current lens design position; Generate the freeform surface shape data corresponding to the current lens design position based on the surface normal vector.

[0011] Optionally, generate freeform surface shape data, including: Obtain the surface normal vector of the current lens design position and the surface normal vectors of adjacent generated lens design positions; The surface normal vector of the current lens design position is compared with the surface normal vectors of adjacent generated lens design positions to obtain the change in the normal vector. The lens point sampling density is determined based on the change in the normal vector, so that the region with a larger change in the normal vector has a higher lens point sampling density than the region with a smaller change in the normal vector. The step distance corresponding to the current lens design position is determined based on the lens point sampling density. Based on the current incident light direction and the surface normal vector of the current lens design position, determine the projection direction located in the tangent plane of the current lens design position; Using the current lens design position, the step distance, and the projection direction as inputs, the next lens design position is updated and obtained. The lens design position is repeatedly updated according to the preset spatial traversal order to generate freeform surface shape data.

[0012] Optionally, S5 includes: Ray tracing processing is performed on the freeform surface data to obtain the actual illuminance values ​​at each detection position on the target illumination surface; Using the actual illuminance value and the target illuminance value at the corresponding detection position as input, difference processing is performed to obtain the illuminance error at each detection position; Based on the illumination error and preset relaxation data at each detection location, the road direction coordinates and lateral direction coordinates of the corresponding asymmetric target mapping location are proportionally corrected to obtain the corrected asymmetric target mapping location. The asymmetric target mapping relationship is updated according to the corrected asymmetric target mapping position, and the freeform surface shape data is regenerated based on the updated asymmetric target mapping relationship; When the illuminance error meets the preset error condition, or the number of iterations meets the preset number condition, it is determined that the preset design termination condition is met; Before outputting the freeform polarizing lens design data, the optical extension corresponding to the LED light source emission space and the optical extension corresponding to the target illumination area are constrained and compared. When the constraint comparison result does not meet the preset optical realizable conditions, the road polarization control data or lens design constraint data are adjusted, and the freeform surface shape data is regenerated based on the adjusted road polarization control data or lens design constraint data.

[0013] Secondly, embodiments of the present invention provide a design device for a polarizing lens of an LED street light based on freeform surface optics, the device comprising: The data acquisition module is used to acquire actual light distribution data of LED light source, target illumination surface data, road polarization control data and lens design constraint data. The target illumination surface data includes target illumination area and target illuminance distribution. The lens design constraint data includes lens material refractive index and lens initial position data. The light energy mapping module is used to establish a light energy mapping relationship between the light energy emitted by the LED light source and the target illumination area based on the actual light distribution data and the target illumination surface data; The polarization correction module is used to perform road direction polarization correction on the target mapping position in the light energy mapping relationship based on the road polarization control data, and generate an asymmetric target mapping relationship. The surface shape generation module is used to determine the optical refraction relationship at each design position on the lens surface based on the asymmetric target mapping relationship and the lens design constraint data, and to generate freeform surface shape data according to the optical refraction relationship. The feedback compensation module is used to perform illuminance evaluation processing on the freeform surface shape data to obtain the actual illuminance distribution of the target illumination surface, perform feedback compensation on the asymmetric target mapping relationship based on the difference between the actual illuminance distribution and the target illuminance distribution, and update the freeform surface shape data based on the feedback-compensated asymmetric target mapping relationship until the preset design termination condition is met. The output module is used to output the design data of the freeform polarizing lens that meets the preset design termination conditions.

[0014] Optionally, an optical realizability verification module may also be included; The optical feasibility verification module is used to perform a constraint comparison between the optical expansion amount corresponding to the LED light source emission space and the optical expansion amount corresponding to the target illumination area. When the constraint comparison result does not meet the preset optical realizability conditions, the optical realizability verification module adjusts the road polarization control data or lens design constraint data, and outputs the adjusted road polarization control data or lens design constraint data to the polarization correction module or the surface generation module. When the constraint comparison result meets the preset optical realizable conditions, the output module outputs the corresponding freeform surface polarizing lens design data.

[0015] The LED street light polarizing lens design method and apparatus based on freeform surface optics according to the present invention have at least the following beneficial effects: The method of this invention establishes a light energy mapping relationship based on actual light distribution data of LED light sources, and combines road polarization control data to correct the road direction polarization of the target mapping position, enabling the lens design to allocate light energy according to actual light output characteristics and road lighting needs. Compared with traditional design methods that rely on experience-based adjustments, simple discrete mapping, or overall translation of the light spot, this method can improve the accuracy of light energy allocation, reduce light waste on the sidewalk and in areas outside the road, and improve the effective illuminance and light utilization rate of the road surface area.

[0016] Meanwhile, the method of this invention provides feedback compensation for the asymmetric target mapping relationship based on the difference between the actual illuminance distribution corresponding to the freeform surface shape data and the target illuminance distribution, and iteratively updates the freeform surface shape data. This suppresses the problem of error accumulation in open-loop calculations, improves the illuminance uniformity and light distribution stability of the target illumination surface, and makes the final output freeform surface polarizing lens design data more consistent with the preset road lighting target. The technical disclosure also records the effect of this technology in increasing the proportion of road surface light, improving average illuminance, and illuminance uniformity through polarization design.

[0017] The device of this invention, through the coordinated processing of a data acquisition module, a light energy mapping module, a polarization correction module, a surface shape generation module, a feedback compensation module, and an output module, forms a closed-loop process for the design of LED streetlight polarizing lenses, from actual light distribution input, light energy mapping, road direction polarization correction, freeform surface shape generation to illuminance feedback compensation. Compared to the traditional method of manually adjusting the lens profile repeatedly and relying on simulation verification, this device can improve the degree of automation in the design and the repeatability of the design results.

[0018] Furthermore, this device can correct the mapping relationship of asymmetric targets based on the illuminance evaluation results and output freeform polarizing lens design data that meets the preset design termination conditions. This reduces manual adjustments and data conversion errors during the design process, improves the matching degree between the lens design results and the target road lighting effect, and facilitates subsequent 3D modeling, simulation verification, and manufacturing.

[0019] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the LED street light polarizing lens design method based on freeform surface optics in Example 1; Figure 2 This is a schematic diagram of the lens polarization direction generatrix in Example 2; Figure 3 This is a schematic diagram of the three-dimensional structure of the freeform surface polarizing lens in Example 2; Figure 4 This is a schematic diagram of the light density distribution on the target surface under the symmetrical lens design of Example 2; Figure 5 This is a schematic diagram of the light density distribution on the target surface under the polarizing lens design in Example 2; Figure 6 This is a schematic diagram of the horizontal illuminance distribution in the road lighting area under the symmetrical lens design of Example 2; Figure 7This is a schematic diagram of the horizontal illuminance distribution in the road lighting area under the freeform surface non-rotationally symmetric polarizing lens design of Example 2; Figure 8 This is a schematic diagram of the symmetrical light distribution design in Example 2; Figure 9 This is a schematic diagram of the asymmetric polarization design in Example 2. Detailed Implementation

[0021] The present invention will be further described in detail below with reference to experimental examples and specific embodiments. However, this should not be construed as limiting the scope of the above-mentioned subject matter of the present invention to the following embodiments. All technologies implemented based on the content of the present invention fall within the scope of protection of the present invention.

[0022] Unless otherwise specified, the use of terms such as "upper," "lower," "left," "right," "center," "inner," "outer," and "side" to indicate orientation or positional relationships in the description of specific embodiments of the present invention is based on the orientation or positional relationships shown in the accompanying drawings, or the orientation or positional relationship in which the product / equipment / device is typically placed during use. These terms are merely for the purpose of facilitating the description of the present invention or simplifying the description in specific embodiments, enabling those skilled in the art to quickly understand the solution, and do not indicate or imply that a particular device / component / element must have a specific orientation, or be constructed and operated in a specific positional relationship. Therefore, they should not be construed as limitations on the present invention.

[0023] In the description of the embodiments of this invention, technical terms such as "first" and "second" only distinguish one entity or operation from another, and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary or secondary relationship of the indicated technical features. In the description of the embodiments of this invention, "multiple" means two or more, unless otherwise explicitly defined.

[0024] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0025] Example 1 This embodiment provides a design method for LED street light polarizing lenses based on freeform surface optics. During their research on secondary optical lens design for LED street lights, the inventors discovered that in road lighting applications, the actual light distribution characteristics of the LED light source, the target lighting area of ​​the road, and the freeform surface shape of the polarizing lens typically belong to different types of design objects. To achieve effective lighting in the road direction, reduce light energy waste in non-target areas, and further generate design data for lens 3D modeling and manufacturing, it is necessary to first solve the problem of accurate mapping between the emitted light energy of the LED light source and the target lighting area of ​​the road. Especially when the actual light distribution of the LED light source exhibits nonlinear variations, the road lighting area requires asymmetrical polarization distribution, the lens surface needs to meet refractive constraints, and the illuminance distribution needs to meet uniformity requirements, relying solely on manual adjustment or conventional open-loop mapping methods for lens design can easily lead to problems such as large target light spot mapping errors, insufficient light energy distribution in the road direction, inability to correct illuminance deviations, and unstable lens surface shape results. These issues, in turn, affect the lighting effect and design repeatability of the LED street light polarizing lens.

[0026] Figure 1 A flowchart illustrating the LED street light polarizing lens design method based on freeform surface optics provided in this embodiment is shown. Figure 1 As shown, the method includes: acquiring actual light distribution data of the LED light source, target illumination surface data, road polarization control data, and lens design constraint data; establishing a light energy mapping relationship between the emitted light energy of the LED light source and the target illumination area based on the actual light distribution data and target illumination surface data; performing road direction polarization correction on the target mapping position in the light energy mapping relationship based on the road polarization control data to generate an asymmetric target mapping relationship; generating freeform surface shape data based on the asymmetric target mapping relationship and lens design constraint data; evaluating the illuminance of the freeform surface shape data and performing feedback compensation and surface shape update based on the evaluation results; and outputting freeform polarizing lens design data after meeting the preset design termination conditions.

[0027] Based on the above understanding, this embodiment first obtains the input data required for the design of LED street light polarizing lenses. The input data includes actual light distribution data of the LED light source, target illumination surface data, road polarization control data, and lens design constraint data. Specifically, the actual light distribution data of the LED light source characterizes the light intensity distribution of the LED light source in different emission directions; the target illumination surface data includes the target illumination area and target illuminance distribution, used to characterize the lighting requirements of the road surface and its related lighting areas; the road polarization control data characterizes the control requirements for the distribution of light energy towards the road direction; and the lens design constraint data includes the refractive index of the lens material and the initial position data of the lens, used to constrain the surface shape generation process of the freeform lens. By obtaining the above input data, the subsequent lens design process can simultaneously consider the actual light emission characteristics of the light source, the road lighting target, and the lens optical constraints, rather than designing solely based on an ideal light source model or empirical profile.

[0028] After acquiring the aforementioned input data, this embodiment establishes a light energy mapping relationship between the emitted light energy of the LED light source and the target illumination area based on the actual light distribution data of the LED light source and the target illumination surface data. Specifically, a design coordinate system can be first established to describe the LED light source, the target illumination surface, and the lens surface. Within this design coordinate system, the position of the LED light source, the range of the target illumination area in the road direction, and the range of the target illumination area in the lateral direction are determined. Then, based on the light intensity distribution in different emission directions represented by the actual light distribution data of the LED light source, the emission space of the LED light source is divided into regions, and the correspondence between each emission region and each target mapping position in the target illumination area is determined. Through this processing method, the emitted light from the LED light source can be allocated to the target illumination area according to the actual light distribution characteristics, reducing the mapping deviation caused by the traditional simple discrete mapping not fully considering actual light distribution changes.

[0029] After establishing the light energy mapping relationship, this embodiment corrects the target mapping position in the light energy mapping relationship by applying road-direction polarization correction based on road polarization control data, generating an asymmetric target mapping relationship. Specifically, the polarization offset corresponding to different outgoing light energy distribution positions is determined based on the road polarization control data, and the coordinates of the target mapping position in the road direction are corrected using the polarization offset, so that the target mapping position is adjusted from the original symmetrical distribution to an asymmetric distribution offset towards the road direction. Through this processing method, some of the light energy originally allocated to the sidewalk or areas outside the road can be transferred to the road surface area, increasing the effective light energy ratio received by the road lighting area and reducing light energy waste in non-target areas.

[0030] During further research into the design process of LED streetlight polarizing lenses, the inventors discovered that simply establishing an asymmetric target mapping relationship is insufficient to directly obtain a usable lens structure. It is also necessary to determine the surface shape of the freeform lens based on the LED light source emission direction, the asymmetric target mapping position, and the refractive properties of the lens material. Therefore, this embodiment, based on the asymmetric target mapping relationship and combined with lens design constraint data, determines the optical refraction relationship at each design position on the lens surface and generates freeform surface shape data based on the optical refraction relationship.

[0031] Specifically, for the current design position on the lens surface, this embodiment uses the LED light source position and the current design position as input to determine the incident light direction from the LED light source to the current design position; it uses the current design position and the corresponding asymmetric target mapping position as input to determine the outgoing light direction from the current design position to the asymmetric target mapping position; then, it performs refractive constraint processing on the incident light direction and the outgoing light direction according to the refractive index of the lens material to determine the surface normal information corresponding to the current design position. Subsequently, the design position on the lens surface is updated according to the surface normal information, and freeform surface shape data is generated point by point. Through this processing method, the lens surface shape generation process can be matched with the light source emission direction, target illumination position, and lens material refractive characteristics, so that the generated freeform surface shape data has a clear optical design basis.

[0032] In the process of generating freeform surface data, this embodiment can also adjust the sampling density of lens points according to the surface normal variation between adjacent design positions. Specifically, the surface normal information of the current design position and the surface normal information of adjacent generated design positions are obtained, and the difference between the two is compared to obtain the normal variation. Based on the normal variation, the lens point sampling density of the corresponding region is determined, so that regions with larger normal variations have higher sampling densities, and regions with smaller normal variations have lower sampling densities. Then, the step distance of the current design position is determined based on the sampling density, and the next design position is generated along the corresponding surface update direction. Thus, the lens point distribution density can be increased in regions with drastic surface changes, reducing the risk of abrupt changes or local discontinuities in the surface, and improving the adaptability of the freeform surface data to subsequent modeling and processing.

[0033] In practical design, the inventors also discovered that if the lens surface shape is generated only once based on the initial mapping relationship, the initial mapping deviation, surface discretization error, or light propagation error may accumulate in subsequent results, leading to inconsistencies between the actual illuminance distribution on the target illumination surface and the preset target illuminance distribution. To address this issue, this embodiment performs illuminance evaluation processing on the freeform surface shape data after generating it, obtaining the actual illuminance distribution of the target illumination surface, and provides feedback compensation for the asymmetric target mapping relationship based on the difference between the actual illuminance distribution and the target illuminance distribution.

[0034] Specifically, this embodiment can perform ray tracing processing on the freeform surface shape data to obtain the actual illuminance values ​​at each detection position on the target illumination surface; compare the difference between the actual illuminance values ​​at each detection position and the corresponding target illuminance values ​​to obtain the illuminance error at each detection position; correct the corresponding asymmetric target mapping position according to the illuminance error to obtain the corrected asymmetric target mapping relationship; and then regenerate the freeform surface shape data based on the corrected asymmetric target mapping relationship. Through the above feedback compensation process, the lens design process can be transformed from a one-time open-loop calculation to a closed-loop correction process based on the illuminance evaluation results, thereby reducing error accumulation and improving the illuminance uniformity and light distribution stability of the target illumination surface.

[0035] During the feedback compensation and surface shape update process, this embodiment determines whether to stop the iteration based on a preset design termination condition. The preset design termination condition may include the illumination error meeting a preset error condition, or the number of iterations meeting a preset number condition. When the preset design termination condition is not met, this embodiment continues to update the freeform surface shape data based on the asymmetric target mapping relationship after feedback compensation; when the preset design termination condition is met, this embodiment outputs the corresponding freeform polarizing lens design data. The freeform polarizing lens design data may include freeform surface shape data, lens generatrix point cloud data, or lens design data used for 3D modeling.

[0036] In one optional implementation, this embodiment can further compare the optical extension corresponding to the LED light source emission space and the optical extension corresponding to the target illumination area before outputting the freeform surface polarizing lens design data. When the constraint comparison result does not meet the preset optical realizability conditions, the road polarization control data or lens design constraint data is adjusted, and the freeform surface shape data is regenerated based on the adjusted road polarization control data or lens design constraint data; when the constraint comparison result meets the preset optical realizability conditions, the corresponding freeform surface polarizing lens design data is output. This reduces the risk of ineffective refraction, unrealizable light distribution, or failure to meet optical propagation constraints in freeform surface lens design.

[0037] Through this embodiment, the design of LED streetlight polarizing lenses can sequentially complete the input of actual light distribution data, the establishment of light energy mapping relationships, road direction polarization correction, freeform surface shape generation, illuminance evaluation, feedback compensation, and design data output. Therefore, this embodiment enables the lens design process in LED road lighting applications to simultaneously consider the actual light output characteristics of the LED light source, the road direction polarization lighting requirements, and the target illuminance feedback results. Compared to traditional design methods that rely on manual experience adjustments or open-loop discrete mapping, this approach can improve the light energy utilization rate in road areas, reduce light energy waste on sidewalks and in areas outside the road, improve the illuminance uniformity of the target lighting surface, and enhance the repeatability and engineering applicability of the freeform surface polarizing lens design results.

[0038] The LED street light polarizing lens design method based on freeform surface optics provided in this invention can be applied to a wide range of road and regional lighting technologies, such as urban road lighting, park road lighting, bridge road lighting, tunnel entrance and exit lighting, parking lot lighting, factory road lighting, smart street light distribution design, and LED secondary optical lens design. In the above implementation, when designing the freeform surface shape of the LED street light polarizing lens, a light energy mapping relationship between the emitted light energy of the LED light source and the target lighting area can be established based on the actual light distribution data of the LED light source. Road polarization control data can be used to correct the road direction polarization of the target mapping position. Furthermore, feedback compensation can be performed on the asymmetric target mapping relationship using illuminance evaluation results, and the freeform surface shape data can be updated based on the asymmetric target mapping relationship after feedback compensation. Therefore, the design process of the LED street light polarizing lens can simultaneously adapt to the actual light emission characteristics of the light source, the road direction polarization lighting requirements, and the target illuminance distribution requirements, thereby achieving directional distribution of light energy to the target road area, reducing light energy waste on the sidewalk side and in areas outside the road, and improving the light energy utilization rate, illuminance uniformity, and repeatability of the lens design results in the road lighting area.

[0039] Example 2 This embodiment provides a design method for LED street light polarizing lenses based on freeform surface optics. This embodiment is a specific implementation of the overall scheme described in Embodiment 1, mainly used to illustrate how, during the design process of an asymmetric polarizing lens for LED street lights, design data for a freeform surface polarizing lens used for road polarized lighting is generated based on the actual light distribution data of the LED light source, target illumination surface data, road polarization control data, and lens design constraint data.

[0040] The polarizing lens design method of this embodiment may include the following main steps: establishing a coordinate system and initializing parameters; energy integral mapping based on the actual light distribution curve; constructing a composite polarization offset function; calculating point-by-point normal vectors and projecting dynamic tangent planes; detecting the illuminance distribution of the target surface and iterating coordinate feedback compensation; and outputting the busbar point cloud and creating a 3D model. These steps correspond to the establishment of light energy mapping relationships, road direction polarization correction, freeform surface shape generation, illuminance evaluation feedback, and freeform surface polarizing lens design data output processes in this application.

[0041] II. Coordinate System and Design Parameters This embodiment first establishes a design coordinate system to describe the LED light source, the target illumination surface, and the lens surface. Specifically, the road direction is taken as the positive x-axis, pointing towards the far end of the road; the direction perpendicular to the road direction is taken as the y-axis, i.e., the horizontal direction; and the vertically upward direction is taken as the z-axis. The luminaire S (including the LED light source) is located 10mm directly above the origin of the coordinate system. mm. The target illumination surface is located at mm plane (lamp post height z=10m). The range of the target light spot in the road direction is determined by whether or not a polarization offset function is introduced. When no polarization design is used, the target light spot is symmetrical in the road direction; when a polarization offset function is introduced... Subsequently, the target light spot's range along the road direction is adjusted to an asymmetric range offset towards the road, thereby distributing more light energy to the road surface area. In this embodiment: (1) The target light spot is in the direction of the road ( The range of the direction is: when the light is not polarized, the symmetrical range is... In this embodiment, mm. After introducing the polarization offset function, the range becomes... This achieves an asymmetric distribution.

[0042] (2) Horizontal ( (Direction) Range: ,Pick mm (total width 40m).

[0043] (3) Refractive index of lens material (PC polycarbonate).

[0044] (4) Divide the light source emission space into equal solid angles. Parts: Radial division into The azimuth is divided into several rings. One partition. Usually taken. , .

[0045] By dividing the space into the above sections, the continuous LED light source emission space can be converted into multiple calculable and mappable emission units, which facilitates the subsequent establishment of the light energy mapping relationship between the emitted light energy and the target illumination area.

[0046] III. Improved Energy Integral Mapping Equation Traditional energy mapping methods typically employ Determining the radial mapping ratio using a simple discrete approximation method The current processing mainly relies on equal mapping based on the emission region number, without fully considering the nonlinear characteristics of the actual light distribution curve of the LED light source as it changes with the emission angle. For LED streetlights, the actual light intensity may vary significantly in different emission angle directions. If a simple discrete mapping is still used, it can easily lead to a mismatch between the initial illuminance distribution on the target illumination surface and the actual light distribution capability.

[0047] To address the aforementioned issues, this embodiment strictly adheres to the principle of energy conservation. Using the actual light distribution curve of the LED light source as input, it integrates and accumulates the light intensity distribution across different emission angle ranges, ensuring that the accumulated emitted light energy corresponding to each radial ring zone matches the target mapping position within the target illumination area. In other words, this embodiment does not simply distribute light energy evenly according to ring zone numbers, but rather determines the position to which each ring zone should be allocated to the target illumination area based on the actual light intensity distribution of the LED light source.

[0048] Specifically, let the first The polar angle corresponding to each ring The following energy integral mapping relationship is satisfied:

[0049] Where j represents the radial ring number, j=1,2,...,N; This represents the maximum emission angle of the LED light source; The actual light distribution curve of an LED light source is used to represent the light intensity distribution of the LED light source in different emission angle directions. When the LED light source is approximately a Lambertian light source, the Lambertian light intensity distribution can be used as the specific form of the actual light distribution curve. , The light intensity is the center light intensity of the LED. From this, the polar angle corresponding to the j-th radial ring can be accurately calculated. Then, the initial radial mapping ratio corresponding to the current radial annular zone can be obtained. :

[0050] After obtaining the initial radial mapping ratio, this embodiment determines the initial mapping point on the target illumination surface based on the initial radial mapping ratio, the road-direction lighting range, and the lateral lighting range. Specifically, the initial coordinates of the target mapping point in the road direction are determined according to the initial radial mapping ratio. The initial coordinates of the target mapping point in the lateral direction are determined based on the initial radial mapping ratio and the azimuth partition position. :

[0051]

[0052] Where i represents the azimuth zone number, i=1,2...M; Correction factor for non-lateral light energy distribution; Let be the polarization offset function corresponding to the j-th ring.

[0053] Through the above-described energy integral mapping process, this embodiment enables the emitted light energy from the LED light source to be distributed to the target illumination area according to the actual light distribution curve, reducing the nonlinear mapping error caused by the traditional discrete approximation, reducing the initial illuminance distribution deviation to within 5%, and providing a more accurate initial target mapping basis for the subsequent freeform surface shape generation.

[0054] IV. Construction of Composite Polarization Offset Function After completing the initial light energy mapping, this embodiment further corrects the target mapping position for road-direction polarization based on road polarization control data. Traditional polarization designs typically use a constant offset to shift the target light spot as a whole. While this method can shift the light spot as a whole towards the road, paraxial rays and large-angle rays have the same offset, making it impossible to finely allocate light energy according to the actual lighting needs of the road surface, sidewalk, and mid-to-long-distance areas.

[0055] This embodiment proposes a composite polarization offset function that varies nonlinearly with the radial annular zone, allowing the polarization offset to change with the radial mapping ratio or the ray angle. This composite polarization offset function can be expressed as:

[0056] in: Maximum polarization offset (mm): This is used to limit the maximum polarization distance in the road direction. In this embodiment, it is taken as... mm; Nonlinear offset rate factor (range 1.5~3.0), used to control the rate of offset growth. In this embodiment, it is set to... ; The secondary fine-tuning coefficient (range -500 to 500) is used to compensate for the position of the mid-range light spot. In this embodiment, it is taken as... .

[0057] The composite polarization shift function has the following characteristics: (1) When the radial mapping ratio When the value is small, the corresponding paraxial ray polarization shift is... It's small enough to retain basic sidewalk lighting; (2) When the radial mapping ratio When the value is large, it corresponds to a large angle of light, and the polarization shift is... A rapid increase in size can concentrate and direct light onto the road surface; (3) Quadratic term It can compensate for the position of the light spot at medium distance, so that the light spot distribution in the medium distance lighting area is more in line with the needs of road lighting.

[0058] Therefore, this embodiment utilizes composite polarization offset to correct the coordinates of the initial target mapping point in the road direction, adjusting the target mapping position from its original symmetrical distribution to an asymmetrical distribution offset towards the road direction, thus generating an asymmetrical target mapping relationship. This asymmetrical target mapping relationship serves as the basis for the target points in the subsequent freeform surface shape generation, guiding the lens to distribute more light energy to the road surface area.

[0059] V. Iterative Calculation of Lens Generatrix Point by Point After obtaining the asymmetric target mapping relationship, this embodiment iteratively calculates the lens generatrix point by point and generates freeform surface shape data based on the lens generatrix.

[0060] (a) Determining the starting point To avoid coinciding with the light source, the starting point is located slightly offset directly above the light source:

[0061] Right now mm.

[0062] (ii) For each pair Repeat the following steps For each group of radial rings and azimuth zones, this embodiment repeats the lens point update process. Let the current lens point be... The corresponding target point is .

[0063] (1) Based on the position of the LED light source Using the current lens point as input, determine the direction of incident light from the LED light source pointing to the current lens point. :

[0064] (2) Using the current lens point and the corresponding asymmetric target mapping point as input, determine the direction of the outgoing light from the current lens point to the asymmetric target mapping point. :

[0065] (III) Calculate the normal vector of the lens surface After determining the incident and outgoing light directions, this embodiment calculates the lens surface normal vector according to the vector form of Snell's law. Specifically, the normal vector is calculated using the refractive index of the lens material. Unit incident light direction and the direction of unit emitted light As input, establish refractive constraint relationships, and determine the surface normal vector of the current lens point based on these refractive constraint relationships.

[0066] According to the vector form of Snell's Law:

[0067] in, As a scalar, Let be the unit normal vector. Solving for , we get:

[0068] Through the above processing, the surface normal vector of the current lens point can simultaneously satisfy the constraints of the LED light source emission direction, the position of the asymmetric target mapping point, and the refractive index of the lens material. The resulting lens generatrix is ​​no longer a simple geometric fit, but rather a freeform surface with a clearly defined refractive control relationship.

[0069] (iv) Dynamic step size and curvature smoothing projection (different from traditional fixed step size) In the process of calculating the lens generatrix point by point, if a fixed step size is used... When projecting onto a tangent plane, abrupt, step-like changes can easily occur in large-angle regions or areas with drastic normal variations, affecting the continuity of the lens generatrix point cloud and potentially increasing the difficulty of subsequent mold processing. Therefore, this embodiment introduces a local curvature adjustment factor to achieve adaptive stepping based on the changes in the surface normal vectors of adjacent lens points.

[0070] in, The curvature sensitivity coefficient (ranging from 0.1 to 0.5) is used in this embodiment. ; This indicates the dynamic step size of the current lens point; This represents the base step size, i.e., the fixed reference step size; This represents the surface unit normal vector at the current lens point; Represents the surface unit normal vector of adjacent generated lens points; This represents the change in the normal vector (a measure of curvature change). When the normal vector changes drastically, the sampling density of lens points in that region can be increased to refine the local surface; when the normal vector changes gradually, the sampling density of lens points in that region can be decreased to improve computational efficiency. This processing method can reduce abrupt changes in the generatrix point cloud in regions with large local curvature changes, improving the continuity of freeform surface data.

[0071] After determining the dynamic step size, this embodiment uses the tangent plane projection method to determine the stepping direction. Specifically, the current incident light direction is projected onto the tangent plane of the current lens point, and the projected direction is taken as the stepping direction of the current lens point. :

[0072] Then, using the current lens point, dynamic step size, and tangent plane projection direction as input, the next lens point is updated and obtained. :

[0073] In this embodiment, to ensure spatial continuity, the iteration order can be set to traverse the outer loop in radial band order and the inner loop in azimuth partition order. When the radial band is fixed, traversing from the first azimuth partition to the last azimuth partition is equivalent to scanning around the z-axis once. Through this spatial traversal method, the polarizing lens generatrix point cloud can be generated point by point.

[0074] (v) Iteration order To ensure spatial continuity, the iteration order is as follows: the outer loop follows a radial ring pattern. The inner loop is based on azimuth angle. .when When fixed, from arrive Traversal is equivalent to going around One axis scan.

[0075] VI. Closed-loop feedback compensation and iterative mechanism (the most inventive core element) Traditional lens design methods typically conclude after a single calculation, lacking verification and correction of the actual illuminance results on the target illumination surface. When there is a deviation in the initial light energy mapping, this deviation accumulates during subsequent lens point recursion, thus affecting the final illuminance distribution of the target illumination surface. To address this issue, this embodiment adds a closed-loop feedback compensation iteration mechanism. Specifically: (1) in the After the second iteration, the actual illuminance distribution on the target surface is calculated using ray tracing. In other words, the current freeform surface data is used as the object to be evaluated, the propagation path of LED light after refraction through a lens is simulated, and the actual illuminance values ​​at each detection position on the target illumination surface are statistically analyzed.

[0076] (2) The difference between the actual illuminance value and the target illuminance value at the corresponding detection location is compared to obtain the illuminance error. :

[0077] Where k represents the iteration round number; This represents the actual illuminance value at the detection position on the target illumination surface after the k-th iteration; Indicates the target illuminance value; This represents the relative illumination error at the detection location during the k-th iteration.

[0078] (3) Introduce relaxation factor (Value range 0.3~0.7), correct the mapping coordinates for the next round:

[0079]

[0080] in, This represents the road direction coordinates of the asymmetric target mapping position corresponding to the detection position at the k-th iteration; The lateral coordinates of the asymmetric target mapping position corresponding to the detection position are determined during the k-th iteration.

[0081] The relaxation factor controls the magnitude of each coordinate correction, preventing excessive single corrections that could lead to iterative oscillations. The corrected asymmetric target mapping position serves as the target point for the next round of lens point updates, used to redetermine the incident light direction, outgoing light direction, surface normal vector, and freeform surface shape data.

[0082] (4) When the maximum error (Error convergence threshold) (Take 0.01) or the number of iterations The loop terminates when the maximum number of iterations is 50.

[0083] Through the aforementioned feedback compensation mechanism, the illuminance uniformity can be improved from the traditional open-loop method. Upgraded to This method can transform a one-time open-loop calculation into a closed-loop correction process based on illuminance evaluation results, thereby improving the illuminance uniformity and light distribution stability of the target illumination surface.

[0084] VII. Optical Expansion Constraints To ensure the physical realizability of the freeform surface shape, this embodiment can also introduce an étendue constraint during the iteration process. Specifically, the étendue corresponding to the LED light source emission space and the étendue corresponding to the target illumination surface receiving area are compared to determine whether the current polarization design and freeform surface shape meet the realizability conditions for optical propagation.

[0085] in, The angle between the emitted ray and the normal direction of the emitting surface of the light source; The range of solid angles from which the light source exits; Indicates the angle between the incident ray and the direction of the normal to the target illumination surface; Indicates the area of ​​the target illumination region; This indicates the optical spread of the LED light source's emission space. It represents the optical spread of the target illumination surface receiving area.

[0086] If the current design does not meet the optical extension constraint, the program can automatically adjust the polarization offset parameter or step parameter and iterate again until the physical realizability condition is met. This process can reduce the risk of total internal reflection, ineffective refraction, or the target area failing to receive the corresponding light energy in freeform lens design.

[0087] VIII. Busbar Features and 3D Modeling The lens generatrix calculated by the above iterative algorithm exhibits significant non-rotational symmetry. Specifically, the generatrix of the streetlight lens in the polarization direction is non-rotational symmetric, and the lens width in the sidewalk direction is significantly narrower than the generatrix width in the road direction. For example... Figure 2 As shown in the schematic diagram of the lens polarization direction generatrix, the light source is located in the lower center, and the sidewalk direction and the road direction are located on both sides of the light source, respectively. Since this embodiment guides more light energy to the road direction, the lens generatrix presents an asymmetrical shape in the road direction and the sidewalk direction.

[0088] Importing the above busbar point cloud data into SolidWorks or other 3D modeling software for lofting modeling yields the corresponding freeform surface polarizing lens 3D model, such as... Figure 3 As shown, this 3D model is used to characterize the final output freeform polarizing lens design data, which can be further used for optical simulation, structural design, or manufacturing.

[0089] IX. Simulation Verification and Technical Effects To verify the beneficial effects of this invention in "increasing the light utilization rate of road surfaces and reducing light waste," the above algorithm was implemented using Python, and simulation calculations were performed using typical parameters. The parameter settings are as follows: Light fixture position S(0,0,10) mm Target surface height H = 10000 mm Symmetrical half-width L_x = 7500 mm, polarization offset D = 4000 mm, actual road direction range [-3500, 7500] mm Horizontal half-width L_y = 20000 mm (total width 40m) The nonlinearity factor α = 1.6, and the lateral compressibility coefficient γ = 0.4. The lens has a refractive index of n=1.58, a grid of N=100, M=100, and a step size Δs = 1.0 mm. (1) Comparison of light energy distribution In the comparison of light energy distribution, the light density of the target surface in the symmetrical design and the polarized design of this embodiment can be integrally statistically analyzed separately. For the symmetrical design, such as... Figure 4 As shown, in the region x < 0, i.e., the area around the sidewalk, the proportion of light received is 50.2%, and in the region x ≥ 0, i.e., the road surface area, the proportion of light received is 49.8%. Figure 4 It is evident that only a portion of the area with the strongest central energy falls on the road, with a significant amount of light energy still distributed to the sidewalk and areas beyond it.

[0090] For the polarization design in this embodiment, such as Figure 5 As shown, in the region x < 0, i.e., the area around the sidewalk, the proportion of light received decreases to 24.8%, while in the region x ≥ 0, i.e., the road surface area, the proportion of light received increases to 75.2%. Figure 5 It is evident that areas with stronger central energy fall more within the road area, with light energy shifting towards the positive direction of the road. Therefore, by introducing a road-direction polarization offset, this embodiment can reduce light energy waste in the area on and outside the sidewalk from 50.2% to 24.8%, and increase the light energy received by the road surface from 49.8% to 75.2%, thereby improving the light utilization rate of the road surface.

[0091] (2) Improved road surface illumination To improve road surface illuminance, street light distribution IES files can be imported into DIALUX to simulate road illuminance distribution. Simulation results show that the average illuminance in the road surface area with x≥0 is 35.7 lx under the symmetrical design and 46.8 lx under the polarized design in this embodiment, an increase of approximately 31%; the overall illuminance uniformity in the road direction is improved from 0.37 to 0.49.

[0092] In the design of road lighting distribution using symmetrical lenses, such as Figure 6 As shown, Figure 6This diagram illustrates the horizontal illuminance distribution in a road lighting area under a symmetrical lens design, showing the distribution at different measuring points within the road lighting area. Overall, the illuminance is higher in the lower-middle region, with a maximum value of approximately 74.4 lx; and lower in the upper-middle region, with a minimum value of approximately 13.3 lx. Table 1 presents the numerical system of horizontal illuminance maintenance values ​​under the symmetrical lens design. The horizontal and vertical coordinates in the table correspond to the measuring point locations on the target lighting surface, and the values ​​in each cell represent the horizontal illuminance maintenance values ​​at the corresponding measuring point.

[0093] As shown in Table 1, the illuminance distribution under the symmetrical lens design is generally lower in the middle and higher on both sides and near the luminaire, indicating that the light energy distribution in the target area is not balanced. Table 2 shows the point illuminance statistics of the horizontal illuminance maintenance values ​​under the symmetrical lens design. The table lists the evaluation indicators such as average illuminance, minimum illuminance, maximum illuminance, overall uniformity, and longitudinal uniformity.

[0094] Table 1 Maintenance values ​​[lx] for horizontal illuminance streetlights (numerical system)

[0095] As shown in Table 2, the average illuminance of the target lighting area under the symmetrical lens design is 35.7 lx, the minimum illuminance is 13.3 lx, the maximum illuminance is 74.4 lx, and the overall uniformity is 0.37. This indicates that although the design can form road lighting in a certain range, there is still room for further improvement in the uniformity of illuminance distribution.

[0096] Table 2 Maintenance values ​​[lx] (point illuminance value) for horizontal illuminance streetlights

[0097] In this embodiment, the road illuminance distribution is designed using a freeform surface non-rotationally symmetric polarizing lens, such as... Figure 7 As shown, Figure 7 This is a schematic diagram of the horizontal illuminance distribution in the road lighting area under the freeform surface non-rotationally symmetric polarizing lens design of this embodiment. The values ​​in the figure represent the horizontal illuminance values ​​at different measuring points within the target lighting area. Overall, the visible light energy is mainly distributed towards the road, resulting in a high illuminance level within the target road area. Compared to the symmetric lens design, this reduces the waste of light energy on the sidewalk side and in areas outside the road.

[0098] Table 3 presents the numerical system of horizontal illuminance maintenance values ​​under the freeform surface non-rotationally symmetric polarizing lens design of this embodiment. The horizontal and vertical coordinates in the table correspond to the measurement point positions on the target illumination surface, and the values ​​in each cell represent the horizontal illuminance values ​​at the corresponding measurement point. As can be seen from Table 3, the polarizing lens design of this embodiment can distribute more light energy to the road lighting area, resulting in a higher illuminance level within the target area and improving the uniformity of illuminance distribution.

[0099] Table 3 Maintenance values ​​[lx] for horizontal illuminance streetlights (numerical system)

[0100] Table 4 presents the statistical results of the horizontal illuminance maintenance values ​​under the freeform surface non-rotationally symmetric polarizing lens design of this embodiment. The table lists evaluation indicators such as average illuminance, minimum illuminance, maximum illuminance, overall uniformity, and longitudinal uniformity. As shown in Table 4, the average illuminance of the target lighting area under the polarizing lens design of this embodiment is 46.8 lx, the minimum illuminance is 23.0 lx, the maximum illuminance is 79.3 lx, and the overall uniformity is 0.49, indicating that this design can improve the illuminance level and illuminance uniformity of the road lighting area.

[0101] Table 4 Maintenance values ​​[lx] (point illuminance value) for horizontal illuminance streetlights

[0102] (3) Light distribution curve Regarding the light distribution profile, such as Figure 8 As shown, the light intensity peak of the symmetrical light distribution design is mainly located at approximately 0°, and the light energy distribution is relatively symmetrical; as Figure 9 As shown, in this embodiment, the peak light intensity of the asymmetric polarization design is shifted from approximately 0° to approximately 26°, with a significant reduction in light intensity in the negative direction, thus achieving a transfer of light energy towards the positive direction of the road. Therefore, this embodiment can reduce light energy wastage on sidewalks and areas outside the sidewalks, improving illuminance and light utilization in the road area.

[0103] Through this embodiment, the design of LED streetlight polarizing lenses can sequentially complete the following steps: coordinate system and parameter initialization, energy integral mapping based on the actual light distribution curve, construction of the composite polarization offset function, point-by-point normal vector calculation and dynamic tangent plane projection, target surface illuminance distribution detection and coordinate feedback compensation iteration, and busbar point cloud output and 3D modeling. Therefore, this embodiment can concentrate more light energy onto the road surface area while retaining the basic pedestrian lighting, improving the average illuminance and illuminance uniformity of the road lighting area, and enhancing the repeatability and engineering applicability of the freeform surface polarizing lens design results.

[0104] This embodiment provides a design device for LED street lamp polarizing lenses based on freeform surface optics. This device can be used to execute the LED street lamp polarizing lens design method based on freeform surface optics described in Embodiment 1 or Embodiment 2. The device can be deployed on computer equipment, an optical design workstation, a server, or integrated into LED street lamp lens design software. It is used to generate freeform surface polarizing lens design data that meets the road polarization lighting requirements based on actual LED light source light distribution data, target illumination surface data, road polarization control data, and lens design constraint data.

[0105] The device described in this embodiment may include a data acquisition module, a light energy mapping module, a polarization correction module, a surface shape generation module, a feedback compensation module, and an output module. These modules can be connected sequentially according to the data processing flow, or they can be implemented using different functional units within the same processor or software program. The data transmitted between the modules may include actual light distribution data, target illumination surface data, light energy mapping relationships, asymmetric target mapping relationships, freeform surface shape data, actual illuminance distribution, feedback compensation results, and final freeform polarizing lens design data.

[0106] The data acquisition module is used to acquire actual light distribution data of the LED light source, target illumination surface data, road polarization control data, and lens design constraint data. The target illumination surface data includes the target illumination area and target illuminance distribution. The target illumination area defines the range of the road illumination area in the road direction, lateral direction, and height direction. The target illuminance distribution represents the expected illuminance at each detection location within the road illumination area. The road polarization control data represents the control requirements for the distribution of light energy towards the road direction. The lens design constraint data includes the refractive index of the lens material and the initial position data of the lens, used to constrain the surface shape generation process of the freeform lens. Through the data acquisition module, the actual light output characteristics of the light source, the road illumination target, and the lens optical design conditions can be uniformly input into the device, providing a data foundation for subsequent light energy mapping, polarization correction, and surface shape generation.

[0107] The light energy mapping module is used to establish a light energy mapping relationship between the emitted light energy of the LED light source and the target illumination area based on actual light distribution data and target illumination surface data. Specifically, the light energy mapping module can first establish a design coordinate system to describe the LED light source, the target illumination surface, and the lens surface. Then, based on the position of the LED light source, the range of the target illumination area in the road direction, and the range of the target illumination area in the lateral direction, the light energy mapping module determines the coordinate range of the target illumination area. Subsequently, the light energy mapping module divides the emission space of the LED light source into multiple emission areas according to the emission angle and azimuth directions. Based on the light intensity distribution represented by the actual light distribution data of the LED light source, the module accumulates the emitted light energy corresponding to each emission area to obtain the light energy allocation ratio corresponding to each emission area. The light energy mapping module determines the target mapping position of each emission area in the target illumination area according to the light energy allocation ratio, thereby obtaining the light energy mapping relationship between the emitted light energy of the LED light source and the target illumination area.

[0108] The polarization correction module is used to correct the road-direction polarization of target mapping positions in the light energy mapping relationship based on road polarization control data, generating an asymmetric target mapping relationship. Specifically, the polarization correction module can use the light energy distribution ratio, maximum polarization data, polarization growth control data, and mid-range polarization compensation data in the light energy mapping relationship as inputs to determine the polarization offset corresponding to the current target mapping position. Then, the polarization correction module uses the polarization offset to correct the coordinates of the current target mapping position in the road direction, obtaining the corresponding asymmetric target mapping position, and generating an asymmetric target mapping relationship based on multiple asymmetric target mapping positions. Through the polarization correction module, the originally symmetrically distributed target mapping positions can be adjusted to an asymmetric distribution offset towards the road direction, allowing more light energy to be distributed to the road surface area.

[0109] The surface shape generation module is used to determine the optical refraction relationship at each design position on the lens surface based on the asymmetric target mapping relationship and lens design constraint data, and to generate freeform surface shape data according to the optical refraction relationship. Specifically, the surface shape generation module can use the position of the LED light source and the current lens design position as input to determine the incident light direction from the LED light source to the current lens design position; and use the current lens design position and the corresponding asymmetric target mapping position as input to determine the outgoing light direction from the current lens design position to the asymmetric target mapping position. Subsequently, the surface shape generation module performs refraction constraint processing on the incident light direction and the outgoing light direction according to the refractive index of the lens material to obtain the surface normal vector of the current lens design position, and updates the lens design position according to the surface normal vector, generating freeform surface shape data point by point.

[0110] Furthermore, the surface shape generation module can determine the lens point sampling density based on the surface normal vector changes between adjacent lens design positions. Specifically, the module obtains the surface normal vector of the current lens design position and the surface normal vectors of adjacent generated lens design positions, compares the differences between them to obtain the normal vector change; it then determines the lens point sampling density of the corresponding region based on the normal vector change, ensuring that regions with larger normal vector changes have higher lens point sampling densities and regions with smaller normal vector changes have lower lens point sampling densities; finally, it determines the step distance corresponding to the current lens design position based on the lens point sampling density, and updates the next lens design position by combining it with the projection direction in the tangent plane. Through this processing method, the surface shape generation module can improve the continuity of freeform surface shape data and reduce the impact of local surface abrupt changes on subsequent 3D modeling and manufacturing.

[0111] The feedback compensation module performs illuminance evaluation processing on the freeform surface data to obtain the actual illuminance distribution of the target illuminated surface. It then compensates for the asymmetric target mapping relationship based on the difference between the actual and target illuminance distributions. Specifically, the feedback compensation module performs ray tracing processing on the freeform surface data to obtain the actual illuminance values ​​at each detection location on the target illuminated surface. It then performs difference processing between the actual illuminance values ​​and the target illuminance values ​​at the corresponding detection locations to obtain the illuminance error at each detection location. Based on the illuminance error and preset relaxation data, the feedback compensation module proportionally corrects the road direction coordinates and lateral direction coordinates of the corresponding asymmetric target mapping location to obtain the corrected asymmetric target mapping location. This corrected asymmetric target mapping location is then output to the surface generation module, enabling the surface generation module to regenerate the freeform surface data based on the updated asymmetric target mapping relationship.

[0112] The feedback compensation module is also used to determine whether the preset design termination conditions are met. Specifically, when the illuminance error meets the preset error condition, or the number of iterations meets the preset number condition, the feedback compensation module determines that the current freeform surface data meets the preset design termination conditions; when the preset design termination conditions are not met, the feedback compensation module continues to feed back the corrected asymmetric target mapping relationship to the surface generation module. Thus, the device can form a closed-loop design process from surface generation, illuminance evaluation, error correction to surface update, reducing the problem of accumulated illuminance deviation caused by one-time open-loop calculations.

[0113] The output module outputs design data for freeform polarizing lenses that meet preset design termination conditions. This design data may include freeform surface shape data, lens generatrix point cloud data, 3D modeling data, or lens design data for optical simulation and manufacturing. Through the output module, designers can import the lens design data that meets the design termination conditions into 3D modeling software, optical simulation software, or manufacturing data generation software for subsequent modeling, verification, and manufacturing of the freeform polarizing lenses.

[0114] In an optional embodiment, the device described in this embodiment may further include an optical feasibility verification module. The optical feasibility verification module is used to perform a constraint comparison between the optical extension corresponding to the LED light source emission space and the optical extension corresponding to the target illumination area, to determine whether the current road polarization control data and freeform surface shape data meet preset optical feasibility conditions. When the constraint comparison result does not meet the preset optical feasibility conditions, the optical feasibility verification module adjusts the road polarization control data or lens design constraint data, and outputs the adjusted road polarization control data or lens design constraint data to the polarization correction module or surface shape generation module; when the constraint comparison result meets the preset optical feasibility conditions, the output module outputs the corresponding freeform surface polarizing lens design data. Through this optical feasibility verification module, the risk of invalid refraction, total internal reflection, or the target illumination area failing to receive the corresponding light energy during the design process can be reduced.

[0115] The device provided in this embodiment enables the design process of LED streetlight polarizing lenses to be completed collaboratively by a data acquisition module, a light energy mapping module, a polarization correction module, a surface shape generation module, a feedback compensation module, and an output module. This device integrates the actual light distribution input of the LED light source, light energy mapping of the target illumination area, road-direction polarization correction, freeform surface shape generation, illuminance feedback compensation, and design data output into a continuous modular processing flow. Compared to the traditional design method that relies on manual experience to adjust the lens profile and repeatedly simulates and verifies, this embodiment improves the automation and repeatability of LED streetlight polarizing lens design, reduces light energy waste on the sidewalk side and in areas outside the road, and improves the light energy utilization rate and illuminance uniformity of the road lighting area.

[0116] It should be understood that the design of each module of the LED street light polarizing lens design device based on freeform surface optics provided in the above embodiments is only illustrated by the division of each functional module in the above description. In practical applications, the above functions can be assigned to different functional modules as needed. That is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above.

[0117] The functional modules in the above embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of the embodiments of the present invention.

[0118] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects.

[0119] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0120] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A design method for LED street light polarizing lenses based on freeform surface optics, characterized in that, Includes the following steps: S1. Obtain actual light distribution data, target illumination surface data, road polarization control data, and lens design constraint data of the LED light source. The target illumination surface data includes the target illumination area and target illuminance distribution. The lens design constraint data includes the refractive index of the lens material and the initial position data of the lens. S2. Based on the actual light distribution data and the target illumination surface data, establish a light energy mapping relationship between the light energy emitted by the LED light source and the target illumination area; S3. Based on the road polarization control data, the target mapping position in the light energy mapping relationship is corrected for road direction polarization to generate an asymmetric target mapping relationship; S4. Based on the asymmetric target mapping relationship and the lens design constraint data, determine the optical refraction relationship at each design position on the lens surface, and generate freeform surface shape data according to the optical refraction relationship; S5. Perform illuminance evaluation processing on the freeform surface shape data to obtain the actual illuminance distribution of the target illumination surface. Based on the difference between the actual illuminance distribution and the target illuminance distribution, perform feedback compensation on the asymmetric target mapping relationship. Update the freeform surface shape data based on the asymmetric target mapping relationship after feedback compensation until the preset design termination condition is met. S6. Output the design data of the freeform polarizing lens that meets the preset design termination conditions.

2. The LED street light polarizing lens design method according to claim 1, characterized in that, S2 include: A design coordinate system is established to describe the LED light source, the target lighting surface, and the lens surface, with the road extension direction as the road direction, the direction perpendicular to the road direction as the lateral direction, and the direction perpendicular to the target lighting surface as the height direction. The coordinate range of the target lighting area is determined based on the position of the LED light source, the range of the target lighting area in the road direction, and the range of the target lighting area in the lateral direction. The emission space of the LED light source is divided into multiple emission areas according to the emission angle and azimuth direction; Establish the correspondence between each emission area and the target mapping position in the target illumination area to obtain the light energy mapping relationship.

3. The LED street light polarizing lens design method according to claim 2, characterized in that, S2 include: Using the actual light distribution data of the LED light source and the emission angle range corresponding to each emission area as input, the light intensity value corresponding to each emission angle sampling position is obtained; According to the solid angle weight corresponding to each emission angle sampling position, the light intensity value in the current emission area is weighted and accumulated to obtain the cumulative emitted light energy corresponding to the current emission area. According to the solid angle weight corresponding to each emission angle sampling position, the light intensity value of the LED light source in the entire emission area is weighted and accumulated to obtain the total emitted light energy. The ratio of the cumulative emitted light energy corresponding to the current emission area to the total emitted light energy is processed to obtain the light energy distribution ratio corresponding to the current emission area. The target mapping position of the current emission area in the target illumination area is determined based on the light energy distribution ratio.

4. The LED street light polarizing lens design method according to claim 3, characterized in that, Determining the target mapping position in the light energy mapping relationship includes: Using the light energy distribution ratio in the light energy mapping relationship, the range of the target illumination area in the road direction, and the range of the target illumination area in the lateral direction as inputs, the radial mapping position corresponding to the current emission area is determined. Based on the radial mapping position and the range of the target lighting area in the road direction, determine the road direction coordinates of the target mapping position; Based on the radial mapping position, the range of the target illumination area in the lateral direction, and the azimuth position corresponding to the current emission area, the lateral coordinates of the target mapping position are determined. By combining the road direction coordinates, the lateral direction coordinates, and the position of the target illumination surface, the target mapping position corresponding to the current emission area is obtained.

5. The LED street light polarizing lens design method according to claim 1, characterized in that, S3 includes: Using the light energy allocation ratio, maximum polarization data, polarization growth control data and mid-range polarization compensation data in the light energy mapping relationship as input, the light energy allocation ratio is mapped to a first offset component that increases as the light energy allocation ratio increases. Based on the mid-range polarization compensation data, the light energy distribution ratio is subjected to quadratic order offset compensation processing to obtain the second offset component. The first offset component and the second offset component are superimposed, and the superposition result is used as the polarization offset corresponding to the current target mapping position; The coordinates of the current target mapping position in the road direction are corrected using the polarization offset to obtain the corresponding asymmetric target mapping position; The asymmetric target mapping relationship is generated based on the mapping positions of each asymmetric target.

6. The LED street light polarizing lens design method according to claim 1, characterized in that, S4 includes: Using the position of the LED light source and the current lens design position as input, determine the direction of incident light from the LED light source to the current lens design position; Using the current lens design position and the corresponding asymmetric target mapping position as input, determine the direction of the emitted light from the current lens design position to the asymmetric target mapping position; The incident light direction is weighted according to the refractive index of the lens material, and the direction difference between the weighted incident light direction and the outgoing light direction is processed to obtain the normal vector direction of the current lens design position. The normal vector direction is normalized to obtain the surface normal vector of the current lens design position; Generate the freeform surface shape data corresponding to the current lens design position based on the surface normal vector.

7. The LED street light polarizing lens design method according to claim 1, characterized in that, Generate freeform surface shape data, including: Obtain the surface normal vector of the current lens design position and the surface normal vectors of adjacent generated lens design positions; The surface normal vector of the current lens design position is compared with the surface normal vectors of adjacent generated lens design positions to obtain the change in the normal vector. The lens point sampling density is determined based on the change in the normal vector, so that the region with a larger change in the normal vector has a higher lens point sampling density than the region with a smaller change in the normal vector. The step distance corresponding to the current lens design position is determined based on the lens point sampling density. Based on the current incident light direction and the surface normal vector of the current lens design position, determine the projection direction located in the tangent plane of the current lens design position; Using the current lens design position, the step distance, and the projection direction as inputs, the next lens design position is updated and obtained. The lens design position is repeatedly updated according to the preset spatial traversal order to generate freeform surface shape data.

8. The LED street light polarizing lens design method according to claim 1, characterized in that, S5 include: Ray tracing processing is performed on the freeform surface data to obtain the actual illuminance values ​​at each detection position on the target illumination surface; Using the actual illuminance value and the target illuminance value at the corresponding detection position as input, difference processing is performed to obtain the illuminance error at each detection position; Based on the illumination error and preset relaxation data at each detection location, the road direction coordinates and lateral direction coordinates of the corresponding asymmetric target mapping location are proportionally corrected to obtain the corrected asymmetric target mapping location. The asymmetric target mapping relationship is updated according to the corrected asymmetric target mapping position, and the freeform surface shape data is regenerated based on the updated asymmetric target mapping relationship; When the illuminance error meets the preset error condition, or the number of iterations meets the preset number condition, it is determined that the preset design termination condition is met; Before outputting the freeform polarizing lens design data, the optical extension corresponding to the LED light source emission space and the optical extension corresponding to the target illumination area are constrained and compared. When the constraint comparison result does not meet the preset optical realizable conditions, the road polarization control data or lens design constraint data are adjusted, and the freeform surface shape data is regenerated based on the adjusted road polarization control data or lens design constraint data.

9. A design device for a polarizing lens for LED streetlights based on freeform surface optics, characterized in that, include: The data acquisition module is used to acquire actual light distribution data of LED light source, target illumination surface data, road polarization control data and lens design constraint data. The target illumination surface data includes target illumination area and target illuminance distribution. The lens design constraint data includes lens material refractive index and lens initial position data. The light energy mapping module is used to establish a light energy mapping relationship between the light energy emitted by the LED light source and the target illumination area based on the actual light distribution data and the target illumination surface data; The polarization correction module is used to perform road direction polarization correction on the target mapping position in the light energy mapping relationship based on the road polarization control data, and generate an asymmetric target mapping relationship. The surface shape generation module is used to determine the optical refraction relationship at each design position on the lens surface based on the asymmetric target mapping relationship and the lens design constraint data, and to generate freeform surface shape data according to the optical refraction relationship. The feedback compensation module is used to perform illuminance evaluation processing on the freeform surface shape data to obtain the actual illuminance distribution of the target illumination surface, perform feedback compensation on the asymmetric target mapping relationship based on the difference between the actual illuminance distribution and the target illuminance distribution, and update the freeform surface shape data based on the feedback-compensated asymmetric target mapping relationship until the preset design termination condition is met. The output module is used to output the design data of the freeform polarizing lens that meets the preset design termination conditions.

10. The LED street light polarizing lens design device according to claim 9, characterized in that, It also includes an optical realizability verification module; The optical feasibility verification module is used to perform a constraint comparison between the optical expansion amount corresponding to the LED light source emission space and the optical expansion amount corresponding to the target illumination area. When the constraint comparison result does not meet the preset optical realizability conditions, the optical realizability verification module adjusts the road polarization control data or lens design constraint data, and outputs the adjusted road polarization control data or lens design constraint data to the polarization correction module or the surface generation module. When the constraint comparison result meets the preset optical realizable conditions, the output module outputs the corresponding freeform surface polarizing lens design data.

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