Tir lens and parameter design method thereof

Abstract

This invention provides a TIR lens and its parameter design method. The method includes: constructing an optical system structure for a TIR lens application scenario; the optical system structure includes a ring-arranged light source, a TIR lens, and an optical chip containing microstructures; each sub-light source in the light source is located at the center of the circular bottom of its corresponding TIR lens; determining the light distribution curve through the optical chip parameters and the light source parameters, and calculating the initial parameters of the first and second free curves in the TIR lens based on the light distribution curve, then establishing a solid simulation model for optical tracking simulation; correcting the initial parameters with the simulated light distribution curve obtained from the simulation, and then performing optical tracking simulation again; repeating the above steps until the spot size and spot uniformity reach the target. The TIR lens designed based on this invention can achieve high luminous efficiency illumination at small angles while also achieving high uniformity of the entire light spot.

Description

Technical Field

[0001] This application relates to the field of lens technology, and in particular to a TIR lens and a method for designing its parameters. Background Technology

[0002] Image encoding technology is a technique that converts raw digital signals into image signals that are easy for cameras to recognize. This technology can store information on images, and its recognition is fast, accurate, and efficient. With the widespread use of smartphones, image encoding technology has been widely applied in people's daily lives, such as barcodes on goods and QR codes for quick payments.

[0003] Studies have shown that retroreflective structures can produce a regular hexagonal array pattern similar to a honeycomb structure. The principle is to control the microscopic surface at specific locations within the retroreflective structure, reflecting the reflected light from that area beyond the receiving surface to form a regular hexagonal pixel array pattern on the receiving surface, similar to a honeycomb. Due to its unique geometric characteristics and advantages, cellular coding demonstrates value in image encoding, exhibiting features such as high space utilization, good symmetry, and excellent visual effects.

[0004] Before using a retroreflective structure to generate cellular codes, it needs to be tested to ensure that the hexagonal light spot generated by the reflection meets the requirements. However, due to the property that the reflected light rays of retroreflection travel against the incident light path, they are easily blocked by the light source, making it difficult for the light spot carrying the retroreflector information to be received by the image sensor located behind the light source.

[0005] One solution is to adopt, for example Figure 1 The ring light source shown is used as the illumination source to illuminate the retroreflective chip, and an image sensor is placed behind the ring light source to receive the retroreflected light. Since the ring light source is hollow, the retroreflected light can pass through this hollow area to reach the image sensor located behind the light source. However, due to its large emission angle and relatively low luminous efficiency, the ring light source results in significant detection noise and low spot brightness. Therefore, to improve this situation, its spatial light intensity needs to be redistributed, i.e., secondary light distribution. Currently, the main light distribution lenses available on the market are "peanut shell" lenses and TIR (Total Internal Reflection) lenses.

[0006] like Figure 2 As shown, TIR lenses refer to lens systems designed using the principle of total internal reflection, and are widely used due to their high-efficiency light-gathering characteristics. However, existing TIR lenses, in order to achieve a smaller light-gathering angle, often disregard the beam pattern, resulting in a primary beam and a noticeable secondary beam. Furthermore, the color space is not uniform, and there is generally a noticeable yellow spot around the beam, failing to achieve uniform light distribution (e.g., ...). Figure 3 As shown in the figure, it is difficult to meet the testing requirements in this scenario. Summary of the Invention

[0007] To address the aforementioned problems in the existing technology, this invention provides a TIR lens and a method for designing its parameters, thereby improving these issues.

[0008] This invention provides a parameter design method for a TIR lens. The TIR lens is rotationally symmetric and includes a refractive region for refracting light and a reflective region for reflecting light. The refractive region and the reflective region are formed by rotating a first free curve and a second free curve, respectively. It includes:

[0009] Step S100: Construct the optical system structure for the TIR lens application scenario; wherein, the optical system structure includes a ring-shaped arrangement of light sources, the TIR lens, and an optical chip containing microstructures; each sub-light source of the light source is located at the center of the circular bottom of its corresponding TIR lens;

[0010] Step S200: Determine the light distribution curve through the optical chip parameters and the light source parameters, calculate the initial parameters of the first free curve and the second free curve in the TIR lens based on the light distribution curve, and then establish a solid simulation model to perform optical tracking simulation.

[0011] Step S300: The initial parameters are corrected by the simulated light distribution curve obtained from the simulation before optical tracking simulation is performed.

[0012] Step S400, repeat steps S200 and S300 until the size and uniformity of the simulated light spot reach the target.

[0013] Preferably, in the optical system structure, a three-dimensional Cartesian coordinate system is established with the plane of the optical chip containing the microstructure as the XOY plane and the normal vector at the center of the plane as the Z-axis.

[0014] Preferably, the cross-sectional shape of the TIR lens on the XOZ observation plane includes the first free curve, the second free curve, an arc connecting the first free curve and the second free curve, a first straight line extending along the Z-axis, and a second straight line extending perpendicular to the first straight line along the X-axis; the second straight line and the arc are configured to form a top plane and an arc surface after rotation; the arc surface is configured to, after receiving incident light rays with an angle of 0 degrees to M degrees from the light source, transmit the incident light rays to the reflection area in a direct manner, and after total internal reflection in the reflection area, refract the light rays through the top plane and then exit.

[0015] The refraction region is configured to refract incident light rays with an angle of M degrees to 90 degrees and transmit them to the top plane, and then emit them after refraction at the top plane; the angle of the light source is the complementary angle between the light emitted by the light source and the Z-axis, and the Z-axis is perpendicular to the top plane.

[0016] Preferably, the connection point of the first free curve and the arc is located inside the connection point of the second free curve and the arc, and with the OZ axis as a reference, the connection point of the first free curve and the arc is located above the connection point of the second free curve and the arc.

[0017] Preferably, the parameters of the first free curve are calculated in the following manner:

[0018] On the XOZ plane, the initial sampling point position is determined according to the lens size, and the angle M at the boundary between the refractive and reflective regions is obtained;

[0019] By calculating the luminous flux from angle M to the 90-degree edge range at the boundary, and based on the ratio of the luminous flux corresponding to the initial sampling point to the total luminous flux of the region, the area of ​​the light spot on the receiving surface is allocated, and the tangent vector of the sampling point is obtained using the law of refraction.

[0020] The next sampling point is obtained based on the tangent vector and the preset step size. The sampling point data of the complete refraction region is obtained by iterative calculation, and the parameters of the first free curve are obtained.

[0021] The parameters of the second free curve are obtained by iteratively calculating the sampling point data of the complete reflection area within the angle range from the 0-degree edge to the boundary, using the same method described above.

[0022] Preferably, step S300 specifically includes:

[0023] Step S310: Obtain the simulated light distribution curve obtained from the simulation. The simulated light distribution curve includes the light distribution curve of the light spot in a single refractive region, the light distribution curve of the light spot in a single reflective region, and the complete light distribution curve of the TIR lens.

[0024] Step S320: Obtain the difference between the three spot light distribution curves and their corresponding theoretical spot light distribution curves, calculate the fitting quadratic function of each spot light distribution curve, and correct the formula between luminous flux and spot radius corresponding to different angles based on the fitting quadratic function to obtain the theoretical light distribution curve.

[0025] Step S330: Based on the theoretical light distribution curve, the optimized structure of the TIR lens is recalculated and optical tracking simulation is performed.

[0026] Preferably, in step S400, the uniformity of the light spot is set to be no less than 90%.

[0027] Preferably, the sub-light source is a 1016 LED bead; the number of sub-light sources is N; the N LED beads are arranged in a ring with equal intervals around the Z-axis of the coordinate system and radius Rc; in the ring arrangement, the line connecting the center point of the short side of the LED bead and the center of the ring arrangement is perpendicular to the short side of the LED bead; the distance from the center of the ring arrangement to the plane of the optical chip is H mm; after the ring arrangement is completed, the N LED beads are rotated so that the normal vector of the light source points to the origin of the coordinate axis.

[0028] Preferably, in TIR lens applications, the distance between the ring light source and the optical chip ranges from 10mm to 200m.

[0029] This invention also provides a TIR lens, which is designed using the parameter design method described above.

[0030] In summary, the TIR lens designed based on this embodiment can control the divergence angle range of the light source within a preset range by adjusting the parameters of the free curve, thereby meeting the requirements of adapting to various application scenarios. In particular, it can achieve high luminous efficiency illumination at small angles in optical chip illumination systems while also achieving high uniformity of the entire light spot. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the ring light source structure;

[0032] Figure 2 This is a model diagram of an existing TIR lens;

[0033] Figure 3 This is a schematic diagram of the light spot formed after the light is distributed by an existing TIR lens;

[0034] Figure 4 This is a flowchart illustrating the parameter design method for a TIR lens provided in the first embodiment of the present invention;

[0035] Figure 5 This is a structural diagram of an optical system for TIR lens applications;

[0036] Figure 6(a) is a cross-sectional view of the TIR lens in Example 1 on the XOZ observation plane;

[0037] Figure 6(b) is a side view of the light spot illuminance of the TIR lens in Embodiment 1;

[0038] Figure 7 A schematic diagram of the design of the first and second free curves generated;

[0039] Figure 8 This is a schematic diagram of the overall curve design of the TIR lens;

[0040] Figure 9 This is a schematic diagram of the receiving surface;

[0041] Figure 10 This is a schematic diagram illustrating the process of calculating the first free curve;

[0042] Figure 11(a) is a cross-sectional view of the TIR lens in Example 2 on the XOZ observation plane;

[0043] Figure 11(b) is a side view of the light spot illuminance of the TIR lens in Embodiment 2;

[0044] Figure 12(a) is a cross-sectional view of the TIR lens in Example 3 on the XOZ observation plane;

[0045] Figure 12(b) is a side view of the light spot illuminance of the TIR lens in Example 3;

[0046] Figure 13(a) is a cross-sectional view of the TIR lens in Example 4 on the XOZ observation plane;

[0047] Figure 13(b) is a side view of the light spot illumination of the TIR lens in Example 4. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0049] Several embodiments of the present invention provide a TIR lens and a method for designing its parameters. The TIR lens designed based on this embodiment can adjust the angle range as needed and can be applied to the illumination of an optical chip system.

[0050] Please refer to Figure 4 The first embodiment of the present invention provides a parameter design method for a TIR lens, which includes:

[0051] S100 is an optical system structure for TIR lens applications.

[0052] Among them, such as Figure 1 and Figure 5 As shown, the optical system structure includes a ring-shaped array of light sources 20, a TIR lens 22, and an optical chip 10 containing microstructures. Each sub-light source of the light source 20 is located at the center of the top plane of the TIR lens 22. The distance between the optical chip 10 containing microstructures and the ring-shaped array of light sources is H mm. The probe light emitted by the light source 20 is retroreflected on the surface of the optical chip 10 and then received by the image sensor 30 located behind the light source 20.

[0053] In the optical system structure, a three-dimensional Cartesian coordinate system is established with the plane of the optical chip 10 containing microstructures as the XOY plane and the normal vector at the center of the plane as the Z-axis.

[0054] The sub-light source is a 1016-type LED bead; the number of LED beads is N; the N LED beads are arranged in a ring with equal intervals around the Z-axis of the coordinate system and radius Rc; in the ring arrangement, the line connecting the center point of the short side of each LED bead and the center of the ring arrangement is perpendicular to the short side of the LED bead; the distance from the center of the ring arrangement to the plane of the optical chip 10 is H mm; after the ring arrangement is completed, the N LED beads are rotated so that the normal vector of the light source 20 points to the origin of the coordinate axis.

[0055] Specifically, in this application scenario, the distance between the light source 20 and the optical chip 10 ranges from 10mm to 200m.

[0056] The TIR lens 22 is a rotationally symmetric body, which includes a top plane, a refractive region connected to the top plane for refracting light, a reflective region for reflecting light, and an arc surface connecting the refractive region and the reflective region.

[0057] Specifically, as shown in Figures 6(a)-6(b), in this embodiment, the cross-sectional shape of the TIR lens 22 on the XOZ observation plane includes a first free curve 1, a second free curve 2, an arc 3 connecting the first free curve 1 and the second free curve 2, a first straight line 4 extending along the Z-axis, and a second straight line 5 extending perpendicular to the first straight line 4 along the X-axis direction.

[0058] The second straight line 5 and the arc 3 are configured to form a top plane and an arc surface after rotation; the first free curve 1 and the second free curve 2 are configured to form a refractive area for refracting light and a reflective area for reflecting light after rotation;

[0059] Moreover, as shown in Figure 6(a), with the OX axis as a reference, the connection point 11 of the first free curve 1 is located inside the connection point 21 of the second free curve 2, and with the OZ axis as a reference, the connection point 11 of the first free curve 1 is located above the connection point 21 of the second free curve 2.

[0060] In this embodiment, the arc surface is configured such that after receiving light rays with an angle of 0 degrees to M degrees from the light source, the light is directly transmitted to the reflection area, undergoes total internal reflection in the reflection area, and is then refracted by the top plane before being emitted.

[0061] The refraction region is configured to refract light rays input from a light source at an angle of M degrees to 90 degrees, and then emit the light rays after refraction at the top plane; wherein, the light source angle is the angle between the light rays emitted by the light source and the Z-axis, and the Z-axis is perpendicular to the top plane.

[0062] S200 determines the light distribution curve through optical chip parameters and light source parameters, calculates the initial parameters of the first free curve and the second free curve in the TIR lens based on the light distribution curve, and then establishes a solid simulation model to perform optical tracking simulation.

[0063] In this embodiment, the light distribution curve is a graphical representation of the light intensity distribution of a light source or luminaire in various directions in space, typically presented in polar coordinates. The light distribution curve primarily affects the morphology of the first and second free curves; this effect is relatively minor and not a key factor influencing the final lens size.

[0064] Among them, such as Figure 7 As shown, the parameters of the first free curve 1 are calculated in the following manner:

[0065] The parameters of the first free curve are calculated as follows:

[0066] On the XOZ plane, the initial sampling point position is determined according to the lens size, and the angle M at the boundary between the refractive and reflective regions is obtained.

[0067] Among them, such as Figure 8 As shown, the length of the line connecting the initial sampling point A and the origin O is x, and the angle between OA and the X-axis is M. Based on experience, the values ​​of angle M and radius x can be initially set. A circle with center O and radius x is drawn, intersecting the X-axis at point C. The coordinates of point C are (x, 0). From point C, the second free curve can be calculated. Point D is the intersection of the second free curve and ray OA. The coordinates of point D can determine the half-width and height of the lens.

[0068] Specifically, when designing the lens, the origin O is first determined, and then the initial sampling point A and two parameters of the initial sampling point A are determined according to the lens size: the boundary angle M and the distance x. The boundary angle M and the distance x are determined within a certain range according to the lens size to be designed. The lens size mainly consists of two parameters: the radius and the height of the lens. These two parameters are related, and generally the radius is sufficient. In this embodiment, the lens radius is between 10mm and 20mm.

[0069] In the subsequent calculations, since points A and C are on the same circle with center O and radius x, point C can be obtained from point A and the distance x.

[0070] The luminous flux from the initial sampling point to a range of 90 degrees is calculated by the angle at the boundary. Based on the ratio of the luminous flux at the calculated sampling point to the total luminous flux of the region, the area of ​​the light spot on the receiving surface is allocated, and the tangent vector of the initial sampling point on the refractive region is obtained using the law of refraction.

[0071] In this embodiment:

[0072] When calculating the total luminous flux of the refracting region:

[0073] Formula for luminous intensity of a light source: ;

[0074] in, The total luminous intensity of the light source. For the light source in Light intensity over an angular range, in this embodiment Angle range is arrive The range formed by the angle, and the formula for calculating the luminous flux within this range is: ;

[0075] This formula can be generalized to:

[0076] In this context, the angle M at the boundary is used as a component in the formula for calculating luminous flux. Using 90 degrees as the formula The total luminous flux within the M-90 degree range can be calculated.

[0077] When calculating the luminous flux within an angle range corresponding to a sampling point, the angle corresponding to the line connecting the sampling point and the origin is given in the luminous flux calculation formula. 90 degrees is the value in this formula. The luminous flux value within this angular range can be calculated.

[0078] In this embodiment, the area allocation of the light spot on the receiving surface is as follows:

[0079] For example, if the luminous flux from 0 to 90 degrees is defined as LT, and the luminous flux from M to 90 degrees is calculated as L1, then the relationship between the spot area SL of the light rays in the M-90 degree range after passing through the lens and the preset total spot area ST is: L1:LT=SL:ST.

[0080] In this embodiment, the target light spot is a uniform circular light spot. The receiving surface can then be divided into concentric rings from the inside out, with a maximum radius (target light spot radius) of R, and the inner radius of the nth ring being... The outer radius is ,like Figure 9 As shown, the area of ​​the central circle at this time is The area of ​​the nth ring is When the receiving surface is divided into n parts, we have ,but , It forms an outgoing ray with the corresponding sampling point.

[0081] In this embodiment, after setting the angle M and radius x, the coordinates of point A are known. By using the ratio of the luminous flux in the range of M-90 degrees to the total luminous flux, the area of ​​the light spot on the receiving surface illuminated by the light from the light source passing through A can be calculated. The radius of the known light spot area corresponds to the known light spot radius. , As can be seen from the coordinates, OA is the incident ray vector at this moment, A Let be the vector of the outgoing ray, which is known. According to the formula Calculated Known According to the formula The normal vector can be calculated. And the tangent component perpendicular to the normal vector, from Starting from the point, the next sampling point is obtained based on the direction of the tangent component and the set step size. The sampling point data of the complete refraction region is obtained by repeated calculations, and then the parameters of the first free curve 1 are obtained.

[0082] Specifically, using the luminous flux of the light source within the range of 0-90 degrees as the standard unit, the point x mm away from the origin in the M-degree direction is taken as the starting point A of the refraction region. The distance from the light source to the optical chip plane is H mm. The radius of the target light spot illuminating the plane of the optical chip is set to R2. The vector of the incident ray is known from the starting point of the refraction region and the origin O. The vector of the outgoing ray is known from the starting point of the refraction region and the light spot radius of the plane of the optical chip. According to the vector form of the law of refraction, we can obtain:

[0083]

[0084] In the formula: ; These are the refractive indices of the medium containing the incident ray and the refractive indices of the medium containing the outgoing ray, respectively. These are the incident ray vector, the outgoing ray vector, and the lens normal vector, respectively.

[0085] After obtaining the lens normal vector in vector form, the tangent vector of the lens surface passing through that point is obtained. ;

[0086] like Figure 10 As shown, after obtaining the lens tangent vector Then, by setting the step size, the value on the refractive region can be obtained. Point, then according to Point of incident light ,pass The angle is used to calculate the corresponding luminous flux. The ratio of this luminous flux to the standard unit of luminous flux corresponding to the refracting region is then used to determine the incident light. The radius of the light spot emitted from the plane is controlled, and the corresponding relationship is as follows:

[0087]

[0088] In the formula: The standard unit for luminous flux is defined as the temperature range from M degrees to 90 degrees. For the incident ray Luminous flux values ​​within the range of the corresponding angle to 90 degrees. The radius of the target light spot. For incident light The radius of the light spot at the target plane after refraction;

[0089] Depend on arrive The vector is the outgoing ray. Then, according to the vector form of the law of refraction, we obtain... Point lens surface tangent vector By doing so, we can obtain sampling points on the complete refractive region, and then connect these sampling points to obtain the parameters of the first free curve.

[0090] In this embodiment, for the second free curve, after obtaining point C, the parameters of the second free curve 2 can be calculated first according to the same calculation principle as the first free curve 1. Then, point D is obtained by intersecting the direction vector (i.e., the dividing angle M) corresponding to the initial point A with the second free curve 2. Point D is the cutoff position of the second free curve 2 and also the outermost point for calculating the lens generatrix.

[0091] The calculation of the parameters of the second free curve 2 is similar to that of the first free curve. It can be calculated simply by replacing the law of refraction in the calculation of the first free curve with the law of reflection. This invention will not elaborate further here.

[0092] S300, the initial parameters are corrected by the simulated light distribution curve obtained from the simulation before optical tracking simulation is performed.

[0093] Specifically, including:

[0094] Step S310: Obtain the simulated light distribution curve obtained from the simulation. The simulated light distribution curve includes the light distribution curve of the light spot in a single refractive region, the light distribution curve of the light spot in a single reflective region, and the complete light distribution curve of the TIR lens.

[0095] Step S320: Obtain the difference between the three spot light distribution curves and their corresponding theoretical spot light distribution curves, calculate the fitting quadratic function of each spot light distribution curve, and correct the formula between luminous flux and spot radius corresponding to different angles based on the fitting quadratic function to obtain the theoretical light distribution curve.

[0096] Specifically, when calculating the fitted quadratic function of the light spot distribution curve, the design goal is complete uniformity, and the coefficient for different angles is 1. After obtaining the deviation value dt between the simulation and the theory, the deviation value dt is multiplied by the scaling factor c (an empirical coefficient, a suitable value is obtained through trial and error) and added to the initial coefficient 1. From the new coefficients for different angles obtained, the quadratic function can be fitted.

[0097] During correction, in an ideal situation, the ratio of luminous flux L to total luminous flux LT corresponding to different angles, as well as the ratio of spot radius R1 to target spot RT at that angle, are the same; therefore, in actual simulation, (L / LT) / (R1 / RT) = fitting function.

[0098] Specifically, during the design process, the luminous flux of the light source from 0 to 90 degrees is divided into N parts (e.g., 100 parts, the number of parts is manually adjusted). At the same time, the light spot is also divided into 100 parts of equal area according to concentric circles. Theoretically, when light with equal luminous flux shines on a target surface of equal area, the entire target surface should have uniform brightness. However, in simulation, unevenness usually occurs. At this time, based on the simulation results, it is determined which area has high intensity and the luminous flux of that area is reduced or the area of ​​that area is increased. When the intensity of a certain area is low, the luminous flux of that area is increased or the area of ​​that area is decreased.

[0099] The fitting function mentioned here is theoretically a straight line y=1 before simulation (with 100 points in the range of x from 0 to 90). After simulation, 100 sets of (L / LT) / (R1 / RT) = negative feedback modulation values ​​are obtained. These 100 negative feedback modulation values ​​are fitted to form the corrected fitting function.

[0100] S330, based on the theoretical light distribution curve, the optimized structure of the TIR lens is recalculated and optical tracking simulation is performed.

[0101] S400, repeat steps S200 and S300 until the spot size and spot uniformity reach the target.

[0102] Specifically, in this embodiment, the uniformity of the light spot in the physical simulation model is first calculated, and it is determined whether the optimized uniformity of the light spot meets the design target uniformity requirement. If the optimized uniformity of the light spot does not meet the design target uniformity requirement, steps S200 and S300 are repeated. If the optimized uniformity of the light spot meets the design target uniformity requirement, the lens structure data for this application scenario is determined. In particular, the uniformity should be no less than 90%.

[0103] Among them, such as Figures 11(a)-11(b) , Figures 12(a)-12(b) , Figures 13(a)-13(b) As shown, these are cross-sectional views of the TIR lens designed according to this embodiment on the XOZ observation plane and side views of the corresponding spot illuminance.

[0104] In summary, the TIR lens designed based on this embodiment can control the divergence angle of the light source within a preset range by adjusting the parameters of the free curve, thereby meeting the requirements of various application scenarios. In particular, it can achieve high luminous efficiency illumination at small angles in optical chip illumination systems while also achieving high uniformity of the entire light spot.

[0105] This invention also provides a TIR lens, which is designed using the parameter design method of any of the above embodiments.

[0106] The technical features of the above embodiments can be combined arbitrarily, and the execution order of the method steps is not restricted. 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.

[0107] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A method for designing parameters of a TIR lens, wherein the TIR lens is rotationally symmetric and includes a refractive region for refracting light and a reflective region for reflecting light, wherein the refractive region and the reflective region are formed by rotating a first free curve and a second free curve, respectively; characterized in that, include: Step S100: Construct the optical system structure for the TIR lens application scenario; wherein, the optical system structure includes a ring-shaped arrangement of light sources, the TIR lens, and an optical chip containing microstructures; each sub-light source in the light source is located at the center of the circular bottom of its corresponding TIR lens; Step S200: Determine the light distribution curve using optical chip parameters and light source parameters, and calculate the initial parameters of the first and second free curves in the TIR lens based on the light distribution curve. Then, establish a solid simulation model for optical tracing simulation. In the optical system structure, a three-dimensional Cartesian coordinate system is established using the plane of the optical chip containing the microstructure as the XOY plane and the normal vector at the center of the plane as the Z-axis. The parameters of the first free curve are calculated as follows: On the XOZ plane, determine the position of the initial sampling point A based on the lens size, and obtain the angle M at the boundary between the refractive and reflective regions. Using the luminous flux from the boundary angle M to 90 degrees, allocate the area of ​​the light spot on the receiving surface based on the ratio of the luminous flux corresponding to the initial sampling point A to the total luminous flux of the region, and obtain the sampling value using the law of refraction. The tangent vector is used to obtain the next sampling point based on the tangent vector and the preset step size. This process is iteratively repeated to obtain the complete sampling point data of the refraction region, thus obtaining the parameters of the first free curve. Similarly, the parameters of the second free curve are obtained by iteratively calculating the complete sampling point data of the reflection region within the angle M range from 0 degrees to the boundary, based on the law of reflection, to obtain the parameters of the second free curve. Specifically, the distribution of the light spot area on the receiving surface is as follows: Let the luminous flux from 0 to 90 degrees be LT, and the luminous flux from M to 90 degrees be L1. Then, the relationship between the light spot area SL after passing through the lens and the preset total light spot area ST in the M-90 degree range is: L1:LT = SL:ST. Assuming the target light spot is a uniform circular light spot, the receiving surface is divided into concentric rings from the inside out, with a maximum radius of R, and the inner radius of the nth ring is... The outer radius is Then the area of ​​the central circle is The area of ​​the nth ring is When the receiving surface is divided into n parts, we have ,but , The emitted ray forms with the corresponding sampling point; after setting the angle M and radius x, the coordinates of point A are known. The area of ​​the light spot on the receiving surface illuminated by the light source passing through point A is calculated using the ratio of the luminous flux within the range of M-90 degrees to the total luminous flux. The radius of the light spot corresponding to this area is known. , Coordinates, where OA is the incident ray vector, A Let be the vector of the outgoing ray, which is known. According to the formula Calculated Known According to the formula Calculate the normal vector And the tangent component perpendicular to the normal vector, from Starting from the point, the next sampling point is obtained based on the direction of the tangent component and the set step size. The sampling point data of the complete refraction region are obtained through repeated calculations, and then the parameters of the first free curve are obtained; among them, These are the refractive indices of the medium containing the incident ray and the refractive indices of the medium containing the outgoing ray, respectively. These are the incident ray vector and the outgoing ray vector, respectively. Step S300: The initial parameters are corrected using the simulated light distribution curves obtained from optical tracing simulation before optical tracing simulation is performed again. Step S300 specifically includes: Step S310: Obtaining the simulated light distribution curves, which include the light distribution curves of individual refractive regions, individual reflective regions, and the complete light distribution curve of the TIR lens; Step S320: Obtaining the differences between the three light distribution curves and their corresponding theoretical light distribution curves, calculating the fitting quadratic function for each light distribution curve based on the differences, and correcting the formula between luminous flux and spot radius at different angles based on the fitting quadratic function to obtain the theoretical light distribution curve; Step S330: Recalculating the optimized structure of the TIR lens based on the theoretical light distribution curves and performing optical tracing simulation; wherein, in calculating the... When fitting a quadratic function to the light distribution curve of the light spot, the design goal is complete uniformity, with a coefficient of 1 for different angles. After obtaining the deviation value dt between the simulation and the theory, the deviation value dt is multiplied by the scaling factor c and added to the initial coefficient of 1. The fitted quadratic function is obtained from the new coefficients for different angles. Specifically, during fitting, the luminous flux of the light source from 0 to 90 degrees is divided into 100 equal parts, and the light spot is also divided into 100 equal areas according to concentric circles. Theoretically, when light with equal flux illuminates a target surface of equal area, the entire target surface should have uniform brightness. However, in simulation, non-uniformity usually occurs. In this case, based on the simulation results, the luminous flux of a region with high intensity is reduced or the area of ​​that region is increased, and the luminous flux of a region with low intensity is increased or the area of ​​that region is decreased. After simulation, 100 sets of (L / LT) are obtained. / (R1 / RT) = negative feedback modulation value. After fitting these 100 negative feedback modulation values, the corrected fitting quadratic function is obtained; where L is the luminous flux corresponding to different angles, R1 is the spot radius at the corresponding angle, and RT is the target spot radius. Step S400, repeat steps S200 and S300 until the size and uniformity of the simulated light spot reach the target.

2. The parameter design method for a TIR lens according to claim 1, characterized in that, The cross-sectional shape of the TIR lens on the XOZ observation plane includes the first free curve, the second free curve, an arc connecting the first free curve and the second free curve, a first straight line extending along the Z-axis, and a second straight line extending perpendicular to the first straight line along the X-axis. The second straight line and the arc are configured to form a top plane and an arc surface after rotation. The arc surface is configured to, after receiving incident light rays with an angle of 0 degrees to M degrees from the light source, transmit the incident light rays to the reflection area in a direct manner, and after total internal reflection in the reflection area, refract the light rays through the top plane and then exit. The refraction region is configured to refract incident light rays with an angle of M degrees to 90 degrees and transmit them to the top plane, and then emit them after refraction at the top plane; the angle of the light source is the complementary angle between the light emitted by the light source and the Z-axis, and the Z-axis is perpendicular to the top plane.

3. The parameter design method for a TIR lens according to claim 2, characterized in that, The connection point of the first free curve and the arc is located inside the connection point of the second free curve and the arc. With the OZ axis as a reference, the connection point of the first free curve and the arc is located above the connection point of the second free curve and the arc.

4. The parameter design method for the TIR lens according to claim 1, characterized in that, In step S400, the uniformity of the light spot is set to be no less than 90%.

5. The parameter design method for a TIR lens according to claim 1, characterized in that, In TIR lens applications, the distance between the light source and the optical chip ranges from 10mm to 200m.

6. A TIR lens, characterized in that, It is designed using the parameter design method described in any one of claims 1 to 5.

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