Facet angle parameter automatic calculation and process parameter mapping method and system

Abstract

The application discloses a kind of facet angle parameter automatic calculation and process parameter mapping method and system, it is related to digital parameter processing technical field;Method includes: the angle difference of each facet junction of lens is acquired in advance;For each facet junction, in the minimum transition bandwidth reference data acquired in advance, according to the corresponding angle difference, form transition bandwidth lower limit list;Based on the optical sensitivity distribution data acquired in advance, form transition bandwidth upper limit list;Based on transition bandwidth lower limit list and transition bandwidth upper limit list, conflict determination and solution are carried out, and form final transition bandwidth list;Based on facet angle matrix and final transition bandwidth list, transition band geometry is generated for each facet junction, and new lens surface model is obtained;The application can consider the dual needs of facet angle keeping and step elimination, so that transition bandwidth adapts to the optical and processing requirements of different regions.

Description

Technical Field

[0001] This invention relates to the field of digital parameter processing technology, and more specifically, to a method and system for automatic calculation of facet angle parameters and mapping of process parameters. Background Technology

[0002] As a core optical component for vehicle safety, the lens's surface array structure directly determines the sharpness of the low beam cutoff line, the high beam focusing ratio, and the anti-glare effect. Precise control of the facet angle parameters is necessary to meet national and European light distribution standards. During the lens facet grinding process, to achieve the preset light distribution performance, an array of facets must be machined on the lens substrate surface. Each facet must have specific angle parameters to adapt to the optical functional requirements of different areas, ensuring that light, after refraction, forms a light pattern distribution that meets safety standards.

[0003] Because of the angular differences between adjacent facets, steps and edges are easily formed at the facet junctions after machining. Such structures can cause light scattering, affecting the optical performance of the lens and compromising the appearance integrity. Therefore, existing technologies typically incorporate transition zones between adjacent facets. By making the angles of the facets continuous, steps and edges are eliminated, ensuring the continuity of the machined surface. The core function of the transition zone is to connect adjacent facets through a gradual change in angle, weakening abrupt changes in shape at the junctions and avoiding grooves and flange defects caused by the superposition of tool influence functions during machining.

[0004] However, the optical sensitivity of the lens surface exhibits a highly non-uniform distribution, with significant differences in tolerance to angle changes across different regions. Optically sensitive areas require extremely high angular accuracy, and excessive smoothing of the angle is unacceptable, otherwise it will deviate from the preset light distribution trajectory. Non-sensitive areas, on the other hand, require sufficient transition width to completely eliminate the step. Current technologies use a uniform width for the transition band, which cannot accommodate this non-uniform optical sensitivity. If the transition band is too narrow, the abrupt angle change at the junction of adjacent facets cannot be completely eliminated, still forming ridges, causing localized light scattering and surface whitening, thus compromising appearance and optical consistency. If the transition band is too wide, the original angle of the facets will be diluted, introducing equivalent angular attenuation in the optically sensitive areas, resulting in a systematic light distribution shift. More importantly, this light distribution shift caused by an improperly wide transition band is difficult to identify in conventional geometric inspection, only revealing itself in the final light pattern inspection or glare index test, making it impossible for current technologies to predict such defects in advance.

[0005] The aforementioned problems directly lead to a large number of defective products that pass geometric inspection but fail in optical performance during lens processing. This not only increases rework costs and raw material losses and reduces mass production efficiency, but may also affect driving safety due to light distribution deviation and glare issues, failing to meet the stringent requirements of automotive headlights for optical performance and processing stability.

[0006] In view of this, the present invention proposes a method and system for automatic calculation of facet angle parameters and mapping of process parameters to solve the above problems. Summary of the Invention

[0007] To overcome the aforementioned deficiencies of the prior art and achieve the above objectives, the present invention provides the following technical solution: a method for automatically calculating facet angle parameters and mapping process parameters, comprising:

[0008] Pre-obtain the angular difference at the junction of each facet of the lens;

[0009] For each facet junction, the minimum width of the transition zone is obtained from the pre-acquired minimum transition zone width reference data based on the corresponding angle difference, forming a list of lower limits for the transition zone width;

[0010] Based on the pre-acquired optical sensitivity distribution data, the maximum width of the transition zone at the junction of each facet is determined, forming a list of upper limits for the width of the transition zone;

[0011] Conflict determination and solution are performed based on the lower limit list and the upper limit list of transition band width to determine the final optimized width of the transition band at the intersection of each facet and form the final transition band width list.

[0012] Based on the facet angle matrix and the final transition band width list, a transition band geometry is generated for each facet junction, and a new lens surface model is obtained.

[0013] Based on the new lens surface model, an array of facets and a transition zone structure are machined on the lens substrate surface to obtain the machined lens.

[0014] Furthermore, the optical sensitivity of each facet boundary is calculated based on the optical sensitivity distribution data; the optical sensitivity of the facet boundary is the one with the larger optical sensitivity value on both sides of the boundary.

[0015] Furthermore, an optical sensitivity threshold is set. When the optical sensitivity at the boundary is not less than the optical sensitivity threshold parameter, it is determined to be an optically sensitive area; otherwise, it is determined to be a non-sensitive area.

[0016] Furthermore, in order to control the angle dilution effect caused by the transition zone within a set range, an allowable equivalent angle deviation parameter is set;

[0017] The angle continuity process within the transition zone is simulated by linear angle gradient, and the equivalent dilution of the transition zone to the facet angle is defined as the equivalent angle deviation.

[0018] The upper limit of the optical constraint angle difference is obtained by limiting the equivalent angle deviation based on the allowable equivalent angle deviation parameter.

[0019] Furthermore, a reference maximum width of the transition zone is set as the reference upper limit for the maximum width of the transition zone in the optically sensitive area;

[0020] When the facet junction is within the optically sensitive area, the maximum width of the transition zone is set to be equal to the maximum width of the reference transition zone, and an angle difference constraint correction is introduced. An angle difference contraction coefficient parameter is set to combine with the upper limit of the optical constraint angle difference to reduce the maximum width of the transition zone.

[0021] Furthermore, when the facet boundary belongs to a non-sensitive area, a maximum width of the extended transition band is set to quantify the maximum allowable width of the transition band in the non-sensitive area;

[0022] The maximum width of the transition band in the non-sensitive area is based on the maximum width of the extended transition band, and an angle difference gain correction is introduced to take into account the influence of the angle difference. That is, the angle difference gain coefficient parameter is set to be combined with the upper limit of the optical constraint angle difference to improve the maximum width of the transition band.

[0023] Furthermore, when the minimum width of the transition zone is less than or equal to the maximum width of the transition zone, the final optimized width of the transition zone is taken as the minimum width of the transition zone; when the minimum width of the transition zone is greater than the maximum width of the transition zone, the final optimized width of the transition zone is taken as the maximum width of the transition zone.

[0024] Furthermore, in the new lens surface model, the angles of the facets on both sides are continuously transitioned within the optimized width range of the final transition zone at each facet junction.

[0025] Furthermore, for each facet junction, a region is taken on both sides and a higher-order surface is used to smoothly blend the facets, so that the angle in the transition zone gradually changes from the angle of the previous facet to the angle of the next facet.

[0026] An automatic calculation system for facet angle parameters and a mapping system for process parameters, comprising:

[0027] The lower limit acquisition module is used to pre-acquire the angle difference at the junction of each facet of the lens; for each facet junction, the minimum width of the transition band is obtained from the pre-acquired minimum transition band width reference data according to the corresponding angle difference, forming a lower limit list of transition band widths;

[0028] The upper limit acquisition module determines the maximum width of the transition zone at the junction of each facet based on the pre-acquired optical sensitivity distribution data, forming a list of upper limits for the transition zone width;

[0029] The width calculation module performs conflict determination and solution based on the lower limit list and the upper limit list of transition band width, determines the final optimized width of the transition band at the intersection of each facet, and forms the final transition band width list.

[0030] The model generation module generates transition zone geometry for each facet junction based on the facet angle matrix and the final transition zone width list, thus obtaining a new lens surface model.

[0031] The processing module is used to process array facets and transition zone structures on the surface of the lens substrate according to the new lens surface model, so as to obtain the processed lens.

[0032] Compared with existing technologies, the technical effects and advantages of the automatic calculation method and process parameter mapping method and system for facet angle parameters proposed in this invention are as follows:

[0033] The present invention first obtains the angular difference at the junction of each facet of the lens, determines the minimum width of the transition zone by combining the minimum transition zone width reference data and forms a lower limit list, then distinguishes between optically sensitive areas and non-sensitive areas based on optical sensitivity distribution data, determines the maximum width of the transition zone in a targeted manner and forms an upper limit list, obtains the final optimized width of the transition zone at each junction through conflict judgment and solution, and then generates a new lens surface model with differentiated transition zones, and finally processes the array facets and transition zone structure according to the model.

[0034] This invention effectively solves the problem in existing technologies where a uniform transition band width cannot adapt to the non-uniform distribution of optical sensitivity on the lens surface. It avoids edge scattering and surface whitening caused by an excessively narrow transition band, and light distribution shift in the optically sensitive area caused by an excessively wide transition band. Its advantages lie in its ability to balance the dual requirements of maintaining facet angles and eliminating steps, allowing the transition band width to adapt to the optical and processing requirements of different areas. This improves the consistency of optical performance and appearance integrity in lens processing, reduces rework costs and raw material waste, increases mass production efficiency, and ensures that the product meets the light distribution standards and driving safety requirements of automotive headlights. Attached Figure Description

[0035] Figure 1 This is a block diagram of an automatic calculation system for facet angle parameters and a mapping system for process parameters according to an embodiment of the present invention;

[0036] Figure 2 This is a flowchart of a method for automatically calculating facet angle parameters and mapping process parameters according to an embodiment of the present invention. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be described in detail, clearly, and completely below with reference to the accompanying drawings. It should be particularly noted that the specific embodiments described below are only for better illustrating and explaining the technical solutions of the present invention, and are intended to enable those skilled in the art to better understand and implement the present invention, and should not be construed as limiting the scope of protection of the present invention. Without departing from the spirit and substance of the present invention, those skilled in the art can modify, adjust, or make equivalent substitutions based on the content disclosed in the present invention, and these should all be considered within the scope of protection of the present invention.

[0038] Example 1:

[0039] Please see Figure 1 As shown, this embodiment discloses an automatic calculation system for facet angle parameters and a mapping system for process parameters, including a lower limit acquisition module, an upper limit acquisition module, a width calculation module, a model generation module, and a processing module. Each module is connected via wired or wireless means to achieve data transmission.

[0040] The lower limit acquisition module is used to pre-acquire the angle difference at the junction of each facet of the lens; for each facet junction, the minimum width of the transition zone is obtained from the pre-acquired minimum transition zone width reference data according to the corresponding angle difference, forming a lower limit list of transition zone widths.

[0041] The original lens facet design angle parameters are directly derived from the existing optical design and are used to characterize the nominal spatial orientation of each facet of the lens surface in the lens coordinate system. Each facet corresponds to a facet normal vector, which is determined by the nominal tilt angle and the nominal azimuth angle. The nominal tilt angle represents the angle between the facet normal vector and the normal axis of the lens coordinate system, and the nominal azimuth angle represents the projection direction angle of the facet normal vector in the lens coordinate system plane. To ensure the deterministic calculation of the angle difference between adjacent facets, the lens coordinate system is fixed as a right-handed coordinate system established with the lens assembly reference plane. The origin of the lens coordinate system is taken at the geometric center of the lens assembly reference plane, and the normal axis of the lens coordinate system is set along the light output direction of the lens.

[0042] The original design model of the automotive headlight lens is a three-dimensional geometric model containing arrayed facet segmentation information. Each facet in this model has a unique facet identifier and a computable facet boundary. Based on the original design model, geometric angle parameters are extracted for each facet. Specifically, within the effective area of ​​the facet, a set of surface sampling points for fitting is extracted according to the facet identifier. The number of points in the sampling point set is determined by a sampling point quantity parameter, for example, a value of 25, to achieve a balance between computational complexity and fitting stability. Planar least-squares fitting is performed on the sampling point set to obtain the fitting plane for the facet, and the facet normal vector is calculated from the fitting plane. Subsequently, the facet normal vector is converted into nominal tilt angle and nominal azimuth angle consistent with the original lens facet design angle parameters, serving as the geometric angle parameters for the facet. This ensures that the geometric angle parameters retain the expression form of the original lens facet design angle parameters while also originating from the computable geometric results of the original automotive headlight lens design model.

[0043] After obtaining the geometric angle parameters of each facet, a facet angle matrix is ​​formed. The facet angle matrix is ​​a two-dimensional matrix structure organized according to the array positions of the lens surface. Its row and column indices correspond to the row and column positions of the facets in the lens surface array, respectively. The matrix elements are the geometric angle parameter vectors of the facets at that array position, which consist of the nominal tilt angle and the nominal azimuth angle. The facet angle matrix is ​​obtained by first calculating the coordinates of the geometric center of each facet in the lens coordinate system based on the array segmentation boundaries of each facet in the original design model of the automotive headlight lens. Then, according to the sorting rules of the geometric centers in the lens coordinate system plane, the facets are mapped to the row and column indices. The sorting rules are limited by the array mapping resolution parameter, for example, a value of 0.5 mm. This parameter is used to divide the projection of the lens surface in the lens coordinate system plane into a regular grid, and the grid cell into which the geometric center of each facet falls is taken as the array position of that facet. This ensures that adjacent elements in the facet angle matrix correspond to adjacent facets in space, facilitating subsequent calculation of the angle difference between adjacent facets.

[0044] The facet angle matrix records the nominal tilt angle and nominal azimuth angle of each facet at each array position, and corresponds one-to-one with the array position of the lens surface. It serves as the basic input for subsequent calculation of the angle difference between adjacent facets and for determining the lower limit list and upper limit list of the transition zone width.

[0045] The matrix elements of the facet angle matrix are the geometric angle parameter vectors of the corresponding facets. These vectors consist of the nominal tilt angle and the nominal azimuth angle. To ensure consistent geometric interpretation of the angle difference calculations, before calculating the angle difference between adjacent facets, each geometric angle parameter vector in the facet angle matrix is ​​converted into a facet normal vector. The facet normal vector is represented as a three-dimensional unit vector in the lens coordinate system. The conversion relationship is as follows: for any facet, the normal axis component of its facet normal vector is equal to the cosine of the nominal tilt angle, its projection length in the lens coordinate system plane is equal to the sine of the nominal tilt angle, and the components projected onto the two orthogonal axes of the lens coordinate system are equal to the product of the sine of the nominal tilt angle and the cosine of the nominal azimuth angle, and the product of the sine of the nominal tilt angle and the sine of the nominal azimuth angle, respectively. This yields the facet normal vector for each facet in the lens coordinate system.

[0046] When traversing adjacent cells of the facet angle matrix, an adjacency definition parameter is used to determine the adjacency relationship. For example, the adjacency definition parameter can be set to 4, indicating that the angle difference is calculated only for the vertically adjacent and horizontally adjacent facets sharing a common edge, so that the angle difference between adjacent facets corresponds one-to-one with the facet boundary and avoids non-true boundaries caused by diagonal adjacency. For each element of the facet angle matrix, it forms a pair of adjacent facets with its right-hand and lower-hand elements, and the angle difference Δθ is calculated for each pair of adjacent facets. The angle difference Δθ is calculated using the angle between the facet normal vectors. For any adjacent facet, the angle difference Δθ is equal to the inverse cosine of the dot product of the facet normal vectors of the two facets, and this inverse cosine is converted into an angle form as the angle difference Δθ. To suppress out-of-bounds in the inverse cosine input caused by numerical errors, a dot product truncation parameter is set. For example, the dot product truncation parameter can be 0.999999999999, i.e., 1-ε, where ε is a very small positive number used to truncate the dot product result between the negative dot product truncation parameter and the dot product truncation parameter, thereby ensuring the effectiveness and stability of the inverse cosine operation.

[0047] After traversal, the calculated angle difference Δθ for each pair of adjacent facets is associated with its corresponding facet boundary index and stored to form the angle difference between adjacent facets. The facet boundary index consists of the row and column indices of the facet angle matrix and adjacent direction identifiers. The adjacent direction identifiers are used to distinguish between left-right and top-bottom boundaries, ensuring that the angle difference between adjacent facets can uniquely locate each boundary of the lens and facilitate subsequent table lookup to obtain the minimum width of the transition zone. And determine the maximum width of the transition band based on optical sensitivity distribution data. Provides the foundation for indexing.

[0048] The minimum transition band width reference data is used to characterize the minimum transition band width required to eliminate steps and edges at the junction of adjacent facets and suppress grooves and flanges caused by the superposition of tool influence functions, given an angle difference Δθ. This data is obtained through machining simulation or process experiments and compiled into a table mapping angle difference Δθ to the minimum transition band width. To ensure the table can be directly used in subsequent calculations, the minimum transition band width reference data is sorted in ascending order of angle difference Δθ, and each record contains at least the angle difference Δθ and the corresponding minimum transition band width.

[0049] For each boundary between adjacent facets, the angle difference Δθ at the boundary is first obtained based on the angle difference between adjacent facets. Then, using Δθ as an index, the initial minimum transition band width at that boundary is calculated from the minimum transition band width reference data. To balance data accuracy and computational stability, an interpolation enable threshold parameter is set, for example, a value of 0.1 degrees, to determine whether to use lookup or interpolation. When the difference between Δθ and a certain angle difference record in the minimum transition band width reference data does not exceed the interpolation enable threshold parameter, a lookup method is used. Specifically, the angle difference record with the smallest difference from Δθ is selected, and the corresponding minimum transition band width is used as the initial minimum transition band width, thus avoiding interpolation errors when the angle difference is sufficiently close to the reference point. When the difference between Δθ and any angle difference record in the minimum transition band width reference data is greater than the interpolation enable threshold parameter, a linear interpolation method is used. Specifically, the minimum transition band width is found in the minimum transition band width reference data that satisfies the interpolation enable threshold parameter. ≤Δθ≤ Record the difference between two adjacent angles, and based on the scaling factor (Δθ- ) / ( - Linear interpolation is performed on the minimum width of the transition band corresponding to the two records to obtain the initial minimum width of the transition band, thus maintaining the continuous change of the minimum width of the transition band with the angle difference when the angle difference falls between the reference points; where, and These are the angle difference values ​​of the two angle difference records adjacent to the current angle difference Δθ in the minimum transition band width reference data, respectively. i is the index of the angle difference record, used to represent the i-th record in the minimum transition band width reference data after being sorted in ascending order by angle difference Δθ.

[0050] After obtaining the initial minimum width of the transition zone, it needs to be corrected based on machining capabilities to ensure that the width allows for a continuous transition in manufacturing and can be stably executed by the CNC machining program. For this purpose, tool radius and minimum feed step parameters are set; for example, the tool radius parameter can be set to 2 mm, and the minimum feed step parameter can be set to 0.02 mm. The correction process includes tool geometric reachability correction and feed discretization correction. Tool geometric reachability correction is used to avoid the minimum width of the transition zone being less than the effective coverage scale of the tool contact patch, which would prevent the formation of a continuous gradient surface. The correction rule is to take the maximum value of the lower limit of the product coefficient between the initial minimum width of the transition zone and the tool radius parameter. The product of the lower limit of the product coefficient and the tool radius parameter is the corrected tool radius parameter. For example, the lower limit of the product coefficient can be set to 0.5, meaning that the minimum width of the transition zone reachable by the tool is the larger of the initial minimum width of the transition zone and the corrected tool radius parameter. Feed discretization correction is used to ensure that the transition band width can be covered by the CNC interpolation trajectory with integer step distances. The correction rule is to divide the minimum width of the transition band that the tool can reach by the minimum feed step distance parameter and round it up, and then multiply it back by the minimum feed step distance parameter to obtain the corrected minimum width of the transition band. This ensures that the transition band area corresponding to the corrected minimum width of the transition band can be stably generated by discrete path points that are not less than the minimum feed step distance parameter, and avoids the actual width of the transition band being less than the design value due to interpolation rounding.

[0051] After completing the above index retrieval and processing capability correction, the minimum width of the corrected transition zone obtained at each facet junction is associated with the facet junction index and stored to form a lower limit list of transition zone widths. The lower limit list of transition zone widths contains the minimum width of the corrected transition zone at each facet junction of the lens and the corresponding facet junction index, which serves as the direct input for subsequent conflict determination and solution with the upper limit list of transition zone widths to determine the final transition zone width list.

[0052] The upper limit acquisition module determines the maximum width of the transition zone at the junction of each facet based on the pre-acquired optical sensitivity distribution data, forming a list of upper limits for the transition zone width.

[0053] Optical sensitivity distribution data characterizes the sensitivity of different regions on the lens surface to changes in facet angles. It is obtained by establishing an optical model of the lens and luminaire, applying subtle angular perturbations to the facet angles of specified regions within the optical model, and performing light distribution calculations. The rate of change of key light distribution indicators to these angular perturbations is then obtained, resulting in optical sensitivity distribution data that corresponds one-to-one with the array positions on the lens surface. To ensure alignment of the optical sensitivity distribution data with the facet boundary index, the data is organized into array positions consistent with the facet angle matrix, and the optical sensitivity value for each region is recorded at each array position.

[0054] Determine the maximum width of the transition zone at each facet junction A list of upper limits for transition band widths is then generated. First, the optical sensitivity of each facet boundary is calculated based on the optical sensitivity distribution data. The boundary optical sensitivity is taken as the larger of the corresponding optical sensitivity values ​​on both sides of the boundary, ensuring that the upper limit of the transition band width is dominated by the more sensitive side, thereby avoiding the introduction of unacceptable equivalent angular attenuation on the sensitive side of the transition band. Subsequently, an optical sensitivity threshold is set, for example, an optical sensitivity threshold of 0.6, to distinguish between optically sensitive and non-sensitive areas. When the boundary optical sensitivity is not less than the optical sensitivity threshold parameter, it is determined to be an optically sensitive area; otherwise, it is determined to be a non-sensitive area. The logic for setting the optical sensitivity threshold is that, under the premise that the optical sensitivity is normalized to 0 to 1, a value of 0.6 is used so that areas with a higher response to angular disturbances are classified as optically sensitive areas, in order to prioritize the stability of light distribution and reduce the risk of light pattern shift.

[0055] To maximize the width of the transition zone Directly related to the risk of beam pattern shift, an allowable equivalent angle deviation parameter is set. For example, the allowable equivalent angle deviation parameter can be set to 0.05 degrees to limit the effective angular deviation of the facets introduced by the transition zone from exceeding this allowable range. The logic for setting the allowable equivalent angle deviation parameter is to control the angular dilution effect caused by the transition zone within a small angular range, while meeting optical performance standards. This keeps the changes in key light distribution indicators within the standard allowable range and shifts the risk of beam pattern shift, which is difficult to detect by geometric inspection, forward. Calculation Phase. The angular continuity process within the transition zone is simulated using a linear angular gradient. The equivalent dilution of the facet angle by the transition zone is defined as the coupling result of half the boundary angle difference and the distribution of the transition zone width on both sides. For this purpose, a transition zone distribution ratio parameter is set; for example, a value of 0.5 indicates that the transition zone width is proportionally distributed on both sides of the boundary, thus obtaining the constraint relationship between the equivalent angular deviation and the transition zone width. Based on the allowable equivalent angular deviation parameter, this equivalent angular deviation is limited, resulting in the upper limit of the optical constraint angle difference. upper limit of optical constraint angle difference This is equal to the allowable equivalent angle deviation parameter divided by the transition band allocation ratio parameter, thus ensuring that when the angle difference Δθ is greater than the upper limit of the optical constraint angle difference... It is necessary to restrict This is to suppress the optical pattern shift caused by the accumulation of equivalent angle deviation. Substituting the numerical example, allowing an equivalent angle deviation parameter of 0.05 degrees and a transition zone allocation ratio parameter of 0.5, the upper limit of the optical constraint angle difference can be obtained. It is 0.1 degrees.

[0056] Based on this, optically sensitive areas are constructed respectively. Determination method and non-sensitive area Method for determination. Set the maximum width of the reference transition zone, for example, a maximum width of 0.3 mm, to be used as the optically sensitive area. The logic for setting the upper limit and maximum width of the reference transition band is to control the width of the transition band to a smaller scale while ensuring the continuity of the transition band, thereby reducing the angular dilution range and avoiding systematic deviations from the preset light distribution trajectory of the optically sensitive area. When the facet boundary belongs to the optically sensitive area, let... Equal to the maximum width of the reference transition band Furthermore, an angle difference constraint correction is introduced, and an angle difference contraction coefficient is set. For example, the angle difference shrinkage coefficient can be set to 0.7, which is used to further tighten the area when the angle difference Δθ is large. The correction rule can be determined by the following formula:

[0057] ;

[0058] in, , and when At that time, due to Through the outer minimum value function Limit the results to no more than This ensures that the larger the angle difference, the less likely the transition band is to expand, thus suppressing the equivalent angle attenuation caused by angle continuity. The reason for this correction is that the optically sensitive area has low tolerance to angle changes; the larger the angle difference, the more likely the transition band is to introduce measurable light distribution drift. Therefore, a nonlinear contraction mechanism is necessary to reduce this. .

[0059] When the facet boundary belongs to a non-sensitive area, set the maximum width of the extended transition band. For example, the maximum width of the extended transition band can be 0.8 mm, allowing for a larger value for quantizing the non-sensitive area. The logic behind setting the maximum width of the extended transition zone is that non-sensitive areas have a weaker response to angular disturbances. Appropriately increasing the width of the transition zone can more effectively eliminate steps and edges and reduce the probability of groove and flange defects, thereby improving appearance consistency and process stability. (Non-sensitive areas) Based on the maximum width of the extended transition band, and introducing an angle difference gain correction to account for the influence of the angle difference Δθ, the angle difference gain coefficient parameter is set. For example, the angle difference gain coefficient parameter can be set to 0.25 to improve... The maximum spread factor parameter for the non-sensitive region is ,in , Used to prevent Unbounded growth can lead to an excessively wide transition zone, introducing uncontrollable surface shape changes. When the facet boundary falls within a non-sensitive region, the maximum width of the transition zone... It can be determined using the following formula:

[0060] ;

[0061] Among them, with The width of the transition zone, serving as the base for the non-sensitive area, ensures sufficient geometric continuity; then, a dimensionless scale is used. The relative intensity of the angle abrupt change at the current boundary is represented. A larger angle difference indicates a stronger morphological abrupt change at the boundary and a higher risk of edges and steps. Therefore, a gain term is used to characterize this. The width of the transition zone is increased proportionally to allow more space for gradual angular changes, thus reducing the risk of residual edges and local scattering; at the same time, an upper bound is used. Cut off to prevent large angle differences. The transition band is widened linearly to avoid introducing excessive surface shape changes and subsequent processing instability. This enhancement mechanism is based on the fact that non-sensitive areas allow for stronger continuous processing, and that larger angle differences are more prone to abrupt morphological changes and edge scattering at the interface; therefore, a moderate increase in the transition band is beneficial. This allows the transition zone to have sufficient width to achieve a smooth transition and reduce visible defects.

[0062] To ensure output Meeting optical performance standards requires additional constraint verification. This verification is necessary because changes in the transition band width alter the effective angle distribution of the facets, thus affecting the near-beam cutoff line position and sharpness, the high-beam focusing ratio, and glare performance. Failure to comply with these constraints will result in adverse effects. If this effect is constrained during the determination phase, defective products may occur where geometric continuity meets the standard but the light distribution deviates from the standard permissible range. Therefore, the calculated values ​​at each facet junction are... Substitute the optical model and at this junction... A local angle continuity perturbation is generated and light distribution calculations are performed to obtain the changes in key light distribution indicators. These changes are then compared to the permissible changes specified in optical performance standards. If the changes exceed the permissible limits, then... The band is contracted proportionally until the change in key light distribution parameters falls within the permissible range, thus ensuring that the upper limit of any transition band width is ultimately constrained by meeting optical performance standards.

[0063] The resulting list of upper limits for transition band width includes the maximum width of the transition band at the junction of each facet of the lens. The corresponding facet boundary index is used to determine and solve for conflicts with the lower limit list of transition band widths to determine the final list of transition band widths, and is used to suppress systematic light distribution shift caused by equivalent angle attenuation in the optically sensitive area.

[0064] The width calculation module performs conflict determination and calculation based on the lower limit list and the upper limit list of transition band widths, determines the final optimized width of the transition band at the intersection of each facet, and forms the final transition band width list.

[0065] The list of minimum transition zone widths provides the minimum corrected transition zone width required at each facet junction to eliminate steps and edges and suppress grooves and flange defects. The list of upper limits for transition band widths gives the maximum allowable width of the transition band at each facet junction under the constraints of optical sensitivity and optical performance standards. These two constraints correspond to manufacturability and optical availability, respectively, and both must be satisfied at the same facet junction to avoid defective products that pass geometric inspection but fail optically. Therefore, conflict determination and resolution are required at each facet junction to determine the final optimized transition band width while satisfying both manufacturability and optical availability constraints. And generate the final list of transition band widths.

[0066] The rules for conflict determination and resolution are based on the feasible region as the core logic. For any intersection of facets, if... ≤ Then, at the intersection of the facets, there exists a feasible region that satisfies both types of constraints, with the lower bound being... The upper bound of the interval is In this case, take = , To prioritize the selection of the transition band width that minimizes optical disturbance within the feasible region, thereby ensuring the transition band possesses the minimum necessary ability to eliminate steps and edges while limiting the scope of angular continuity to a minimum scale, this reduces the risk of equivalent angular attenuation caused by the transition band and decreases the probability of systematic light distribution shift in the optically sensitive area. The effect of this rule is to minimize the transition band width while maintaining processing continuity, thus achieving geometric continuity with minimal surface modification, and prioritizing light distribution stability.

[0067] For any intersection of facets, if > If the boundary of the facet does not simultaneously satisfy both the manufacturability and optical usability constraints, then the transition band width is selected as... = To prioritize optical availability constraints and mitigate the risk of light distribution shift when two types of constraints cannot be simultaneously satisfied, optical performance failure directly leads to failure to meet optical performance standards and poses a driving safety risk. While residual fine edges may cause local scattering or surface whitening, they still offer room for assessment and correction in subsequent manufacturing verification feedback and optical performance testing data. By strictly limiting the width of the transition band in the conflict area within the optically permissible range, irreversible systemic light distribution shifts caused by the accumulation of effective facet angle deviations due to an excessively wide transition band are avoided. Simultaneously, the risk of geometric defects is made explicit and incorporated into subsequent closed-loop processing.

[0068] To facilitate targeted tracking of conflict areas during subsequent manufacturing verification feedback, a conflict marking parameter is set with a value of 1, and a conflict mark is generated at each facet boundary. > When, the collision marker at the interface of the facets is set to the collision marker parameter value of 1. ≤ When this happens, the conflict flag at the facet junction is set to 0. The logic for setting the conflict flag is to explicitly encode infeasibility cases and separately attribute local surface defects and light distribution shifts in that region. For example, when a facet junction... It is 0.6 mm and When the value is 0.3 mm, it meets the requirements. > ,Pick With a diameter of 0.3 mm and a collision mark of 1, at the junction of a certain facet... 0.2 mm and When the value is 0.3 mm, it meets the requirements. ≤ ,Pick It is 0.2 mm and the collision mark is 0.

[0069] The resulting list of final transition band widths includes the optimized final transition band widths at the junctions of each lens facet. The corresponding facet boundary index and conflict marker are used to generate new lens surface models and to conduct key evaluation and closed-loop correction of conflict areas during the manufacturing verification feedback stage.

[0070] The model generation module generates transition zone geometry for each facet junction based on the facet angle matrix and the final transition zone width list, thus obtaining a new lens surface model.

[0071] The facet angle matrix is ​​used to provide the geometric angle parameter vector for each facet and determine the spatial adjacency of adjacent facets in the lens surface array. The final transition band width list is used to provide the optimized final transition band width at the interface of each facet. And the corresponding facet boundary index, so that the transition zone geometry can be constructed according to the differentiated width at the facet boundary and remain consistent with the preceding computation link.

[0072] Optimize width based on final transition band A transition zone geometry is generated for each facet junction to obtain a new lens surface model. First, the facets corresponding to the facet junction indices are located on both sides of the CAD model, and the transition zone boundaries are determined on each facet. To ensure the transition zone width is geometrically reproducible, a transition zone half-width parameter is set to 0.5 × 10⁻⁶. The half-width parameter of the transition zone is offset along the normal direction of the facet boundary line on both facet surfaces, resulting in two transition zone boundary lines. One transition zone boundary line is located on the first facet surface of the facet boundary line, and the other transition zone boundary line is located on the second facet surface of the facet boundary line. This method of determining the transition zone boundary ensures that the transition zone expands to a uniform width on both sides of the facet boundary line, thus maintaining consistency with the transition zone allocation ratio parameter and facilitating subsequent control of the continuous effect range of the transition zone angle. Inside.

[0073] After obtaining the two transition zone boundary lines, the boundary tangent and boundary normal of each facet are extracted at the transition zone boundary lines, and the facet normal vectors of both facets are obtained based on the facet angle matrix. To ensure that the transition zone can simultaneously eliminate steps and edges and avoid secondary bends in the transition zone region, the transition zone is constructed using a high-order surface with first-order continuity, so that the transition zone satisfies tangential continuity with the facets on both sides at the two transition zone boundary lines. For this purpose, an end tangential continuity order parameter is set, with a value of 1, indicating that the transition zone surface satisfies at least first-order continuity with the adjacent facets at the two transition zone boundary lines, thereby eliminating abrupt changes in geometric normals at the facet junctions and reducing the risk of light scattering and surface whitening. The transition zone surface is constructed by establishing local parametric coordinates along the width direction of the transition zone. The width parameter varies from 0 to 1, with 0 corresponding to the first transition zone boundary and 1 corresponding to the second transition zone boundary. Then, the facet normal vectors of both sides are continuously interpolated within this parametric coordinate system to obtain the target normal vector field for each point within the transition zone. This target normal vector field is then integrated to generate the transition zone surface. To ensure that the interpolated normal vectors remain unit vectors and to avoid the influence of normal vector length drift introduced by interpolation on the surface morphology, a normal vector normalization parameter is set. The normalization parameter is set to 1, indicating that each interpolated normal vector is normalized to a length of 1. This ensures that the slope variation of the transition zone surface originates only from the angle difference between the two facets without introducing additional scale distortion.

[0074] To further control the dilution effect of the transition zone on the facet angles on both sides and to automatically match the transition between the optically sensitive and non-sensitive areas, a transition curvature control coefficient parameter is set. For example, the transition curvature control coefficient parameter can be set to a value of 2, which is used to optimize the width of the same final transition zone. The distribution of angle changes within the transition zone is adjusted. Specifically, a nonlinear reparameterization is applied to the width direction parameter. The width direction parameter is first mapped using a power function to obtain the reparameterized parameter, where the reparameterized parameter is equal to the transition curvature control coefficient parameter of the width direction parameter raised to a power. This reparameterized parameter is then used as the interpolation weight for continuous interpolation of the normal vector, making the angle change smoother near the boundary and concentrated in the middle. This reduces residual edges at the boundary and lowers the risk of grooves and flanging caused by the superposition of tool influence functions while maintaining tangential continuity at the ends. The reason for this treatment is that the boundary of the transition zone is the most sensitive location for machining trajectory switching and contact patch overlap. By shifting the angle change from the boundary to the middle of the transition zone, the abrupt morphological changes at the boundary can be reduced and machining stability can be improved. In the numerical example, when the transition curvature control coefficient parameter is 2, the reparameterized parameter corresponding to a width direction parameter of 0.5 is 0.25, allowing the middle of the transition zone to bear a larger angle change, thereby weakening the slope change at the boundary.

[0075] After generating the transition zone surface, the transition zone surface at each facet junction is topologically fused with the facets on both sides. Then, in the CAD model, the original facets of the junction region are replaced with the facet junction index, resulting in a new lens surface model containing the variable transition zone. Due to the final optimized transition zone width... The optically sensitive area has been determined by the final transition band width list. A smaller size reduces the range of continuity in the transition zone, thus achieving a steep but continuous transition while maintaining tangential continuity at the ends. This suppresses systematic light distribution shift caused by equivalent angular attenuation, and the non-sensitive area corresponds to... A larger transition zone allows for a wider range of continuity, resulting in a smoother transition that more effectively eliminates steps and edges and reduces the risk of surface scattering.

[0076] The new lens surface model includes the transition zone geometry generated at the junctions of each facet based on the final transition zone width list, and maintains a spatial organization consistent with the facet angle matrix and facet junction index. This model is used for subsequent generation of CNC machining programs and for the closed loop of feedback between optical simulation results data verification and manufacturing verification.

[0077] The processing module is used to process array facets and transition zone structures on the surface of the lens substrate according to the new lens surface model, so as to obtain the processed lens.

[0078] The new lens surface model includes an array of facets and transition zone geometry generated based on a final transition zone width list, which contains the optimized final transition zone widths at the interfaces of each facet. The facet boundary index is used to constrain the consistency of machining trajectory density and process parameters at different facet boundaries when generating CNC machining programs, so as to ensure that the transition zone geometry can be stably reproduced in actual machining.

[0079] The new lens surface model was converted into an executable CNC machining program, and the array facets and transition zone structure were machined on the lens substrate material. First, the new lens surface model was discretized. A surface discretization distance parameter of 0.05 mm was set to discretize the new lens surface model into a regular sampling grid in the lens coordinate system and output a set of tool positions, thereby controlling the CNC program length while ensuring surface fitting accuracy. Then, the tool axis posture was calculated for each tool position. The tool axis posture was determined based on the surface normal vector at that tool position, ensuring that the tool and the new lens surface model follow the normal vector during local contact, thereby reducing cutting force fluctuations and lowering the risk of surface scratches on transparent parts. To prevent abrupt changes in the tool axis posture at the facet junction, a tool axis posture continuity threshold parameter is set with a value of 1.00 degrees. When the tool axis posture change at adjacent tool points exceeds the tool axis posture continuity threshold parameter, the tool axis posture is interpolated and smoothed to ensure a continuous transition between adjacent tool points, thereby ensuring that the machining trajectory does not introduce additional posture abrupt changes near the facet junction.

[0080] When generating the machining trajectory for the array facets, the new lens surface model is divided into facet machining regions and transition zone machining regions using the array position corresponding to the facet angle matrix as an index, and trajectories are generated separately for each. The facet machining region uses an isoparametric scanning method to generate the machining path, setting the facet machining step distance parameter, for example, a value of 0.1 mm, to ensure uniform material removal and surface shape consistency in the facet region. The transition zone machining region is constrained by the final transition zone width list; for each facet boundary index, the width range of the transition zone machining region is determined as the final optimized transition zone width. Within this width range, a densified trajectory is generated, and a transition zone densification ratio parameter is set. For example, the transition zone densification ratio parameter can be set to 2, which is used to set the actual step distance of the transition zone processing area to the facet processing step distance parameter divided by the transition zone densification ratio parameter, thereby making the step distance of the transition zone processing area 0.05 mm. This improves the processing resolution of the continuous surface area of ​​the transition zone and reduces the risk of step residue. The logic of this densification setting is that the transition zone area undertakes the facet angle continuity, and the local slope changes are more concentrated, requiring higher trajectory resolution to avoid discretization marks and residual edges caused by excessive step distance.

[0081] After forming a complete set of tool position points and a tool axis posture sequence, a CNC machining program is generated based on the interpolation format of the CNC system. The CNC machining program includes at least coordinate position commands and tool axis posture commands, and outputs the faceted machining area trajectory and the transition zone machining area trajectory sequentially according to the machining sequence. To ensure the reproducibility of the transition zone width in actual machining, a transition zone width verification parameter is set. For example, the transition zone width verification parameter can be set to 0.02 mm. This parameter is used to perform geometric verification of the tool position point distribution in the transition zone machining area after generating the CNC machining program. The verification method involves calculating the coverage width of the tool position point set in the normal direction of the faceted boundary and comparing it with the corresponding final optimized transition zone width. Comparison, when the coverage width is compared with the final transition band optimization width When the difference exceeds the transition zone width verification parameter, the tool point density in the transition zone machining area is automatically increased until the transition zone width verification parameter constraint is met, thereby ensuring that the CNC machining program can form a transition zone geometry width consistent with the new lens surface model on the lens substrate material after execution.

[0082] Finally, the CNC machining program is loaded into the machining equipment, and precision machining is performed on the lens substrate material according to the CNC machining program. The surface forming of the array facets and the continuous forming of the transition zone structure are completed in sequence to obtain the machined automotive headlight lens, whose surface includes a transition zone structure that is consistent with the array facets and the final transition zone width list.

[0083] Example 2:

[0084] Please see Figure 2 As shown, this embodiment provides a method for automatically calculating facet angle parameters and mapping process parameters, including:

[0085] Pre-obtain the angular difference at the junction of each facet of the lens;

[0086] For each facet junction, the minimum width of the transition zone is obtained from the pre-acquired minimum transition zone width reference data based on the corresponding angle difference, forming a list of lower limits for the transition zone width;

[0087] Based on the pre-acquired optical sensitivity distribution data, the maximum width of the transition zone at the junction of each facet is determined, forming a list of upper limits for the width of the transition zone;

[0088] Conflict determination and solution are performed based on the lower limit list and the upper limit list of transition band width to determine the final optimized width of the transition band at the intersection of each facet and form the final transition band width list.

[0089] Based on the facet angle matrix and the final transition band width list, a transition band geometry is generated for each facet junction, and a new lens surface model is obtained.

[0090] Based on the new lens surface model, an array of facets and a transition zone structure are machined on the lens substrate surface to obtain the machined lens.

[0091] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

[0092] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for automatically calculating facet angle parameters and mapping process parameters, characterized in that, include: Pre-obtain the angular difference at the junction of each facet of the lens; For each facet junction, the minimum width of the transition zone is obtained from the pre-acquired minimum transition zone width reference data based on the corresponding angle difference, forming a list of lower limits for the transition zone width; Based on the pre-acquired optical sensitivity distribution data, the maximum width of the transition zone at the junction of each facet is determined, forming a list of upper limits for the width of the transition zone; Conflict determination and solution are performed based on the lower limit list and the upper limit list of transition band width to determine the final optimized width of the transition band at the intersection of each facet and form the final transition band width list. Based on the facet angle matrix and the final transition band width list, a transition band geometry is generated for each facet junction, and a new lens surface model is obtained. Based on the new lens surface model, an array of facets and a transition zone structure are machined on the lens substrate surface to obtain the machined lens.

2. The method for automatically calculating facet angle parameters and mapping process parameters according to claim 1, characterized in that, The optical sensitivity of each facet is calculated based on the optical sensitivity distribution data; the optical sensitivity of the facet is the one with the larger optical sensitivity value on both sides of the facet.

3. The method for automatically calculating facet angle parameters and mapping process parameters according to claim 2, characterized in that, An optical sensitivity threshold is set. When the optical sensitivity at the boundary is not less than the optical sensitivity threshold parameter, it is determined to be an optically sensitive area; otherwise, it is determined to be a non-sensitive area.

4. The method for automatically calculating facet angle parameters and mapping process parameters according to claim 3, characterized in that, In order to control the angle dilution effect caused by the transition zone within a set range, an allowable equivalent angle deviation parameter is set. The angle continuity process within the transition zone is simulated by linear angle gradient, and the equivalent dilution of the transition zone to the facet angle is defined as the equivalent angle deviation. The upper limit of the optical constraint angle difference is obtained by limiting the equivalent angle deviation based on the allowable equivalent angle deviation parameter.

5. The method for automatically calculating facet angle parameters and mapping process parameters according to claim 4, characterized in that, Set the maximum width of the reference transition zone as the reference upper limit of the maximum width of the optically sensitive area transition zone; When the facet junction is within the optically sensitive area, the maximum width of the transition zone is set to be equal to the maximum width of the reference transition zone, and an angle difference constraint correction is introduced. An angle difference contraction coefficient parameter is set to combine with the upper limit of the optical constraint angle difference to reduce the maximum width of the transition zone.

6. The method for automatically calculating facet angle parameters and mapping process parameters according to claim 4, characterized in that, When the facet boundary belongs to the non-sensitive area, set the maximum width of the extended transition band to quantify the maximum allowable width of the transition band in the non-sensitive area. The maximum width of the transition band in the non-sensitive area is based on the maximum width of the extended transition band, and an angle difference gain correction is introduced to take into account the influence of the angle difference. That is, the angle difference gain coefficient parameter is set to be combined with the upper limit of the optical constraint angle difference to improve the maximum width of the transition band.

7. The method for automatically calculating facet angle parameters and mapping process parameters according to claim 1, characterized in that, When the minimum width of the transition zone is less than or equal to the maximum width of the transition zone, the final optimized width of the transition zone is taken as the minimum width of the transition zone. When the minimum width of the transition zone is greater than the maximum width of the transition zone, the final optimized width of the transition zone is taken as the maximum width of the transition zone.

8. The method for automatically calculating facet angle parameters and mapping process parameters according to claim 1, characterized in that, In the new lens surface model, the intersection of each facet is within the optimized width of the final transition zone, allowing for a continuous transition of the facet angles on both sides.

9. The method for automatically calculating facet angle parameters and mapping process parameters according to claim 8, characterized in that, For each facet junction, a region is taken on both sides, and a higher-order surface is used to smoothly blend the facets, so that the angle in the transition zone gradually changes from the angle of the previous facet to the angle of the next facet.

10. A system for automatically calculating facet angle parameters and mapping process parameters, used to implement the method for automatically calculating facet angle parameters and mapping process parameters as described in any one of claims 1-9, characterized in that, include: The lower limit acquisition module is used to pre-acquire the angle difference at the junction of each facet of the lens; For each facet junction, the minimum width of the transition zone is obtained from the pre-acquired minimum transition zone width reference data based on the corresponding angle difference, forming a list of lower limits for the transition zone width; The upper limit acquisition module determines the maximum width of the transition zone at the junction of each facet based on the pre-acquired optical sensitivity distribution data, forming a list of upper limits for the transition zone width; The width calculation module performs conflict determination and solution based on the lower limit list and the upper limit list of transition band width, determines the final optimized width of the transition band at the intersection of each facet, and forms the final transition band width list. The model generation module generates transition zone geometry for each facet junction based on the facet angle matrix and the final transition zone width list, thus obtaining a new lens surface model. The processing module is used to process array facets and transition zone structures on the surface of the lens substrate according to the new lens surface model, so as to obtain the processed lens.

Images