A method of fitting a generatrix to a lens, a lens and a lens assembly

Abstract

The application discloses a lens generatrix fitting method, a lens and a lens assembly, wherein the lens generatrix fitting method comprises the following steps: dividing total light flux into multiple sub light fluxes equally, and calculating the corresponding angle of the sub light flux; dividing the light receiving surface into multiple irradiation areas which are equal in area and concentric; dividing the generatrix b into multiple first segments and the generatrix c into multiple second segments; according to the iteration principle, calculating the end point coordinates of the next first segment and the second segment according to the known end point coordinates of the previous first segment and the second segment. Dividing the total light flux into multiple sub light fluxes and then dividing the light receiving surface into multiple areas which are equal in area, i.e. the light flux in each area is the same, can improve the uniformity of the light spot on the light receiving surface; the lens can basically gather the light emitted by the light source on the light receiving surface, especially the light at the edge, and can reduce the 10% light intensity angle, thereby reducing the UGR value.

Description

Technical Field

[0001] This invention relates to the field of lighting technology, and in particular to a method for fitting the generatrix of a lens, a lens, and a lens assembly. Background Technology

[0002] Indoor lighting provides illumination for people indoors, and this illumination also has varying effects on people's comfort. The UGR (Uniform Glare Index) is an indicator for evaluating an individual's comfort level with indoor lighting. Currently, luminaires with large beam angles (such as downlights) have uneven light spots, and their UGR values ​​often far exceed the UGR threshold of 19 for human eye comfort, thus reducing human comfort. The uniformity of the light spot of luminaires with large beam angles needs further improvement, and their UGR values ​​need further reduction. Summary of the Invention

[0003] The main objective of this invention is to propose a method for fitting the generatrix of a lens, a lens, and a lens assembly, aiming to solve the technical problems of uneven light spots and high UGR values ​​in existing lamps.

[0004] To achieve the above objective, this invention proposes a generatrix fitting method for a lens, wherein the lens includes an incident surface and an exit surface, and the fitting method for the generatrix b of the incident surface and the generatrix c of the exit surface includes the following steps:

[0005] S1: Obtain the total luminous flux of the central light source, divide the total luminous flux into multiple sub-luminous fluxes, and calculate the angle corresponding to each sub-luminous flux.

[0006] S2: Divide the light receiving surface into multiple concentric illumination areas of equal area, calculate the radius of each concentric area, and obtain the distance from the central light source to the light receiving surface;

[0007] S3: Divide busbar b into multiple first segments and busbar c into multiple second segments, so that the multiple sub-light fluxes, multiple first segments, multiple second segments and multiple irradiation areas correspond one-to-one;

[0008] S4: Obtain the coordinates of the starting points of busbar b and busbar c;

[0009] S5: Based on the angle, the radius, the distance, and the starting point coordinates, and according to the iteration principle, calculate the endpoint coordinates of the next first segment and the next second segment from the known endpoint coordinates of the previous first segment and the known endpoint coordinates of the previous second segment;

[0010] S6: Connect the endpoints of the multiple first segments sequentially to fit a bus line b, and connect the endpoints of the multiple second segments sequentially to fit a bus line c.

[0011] When fitting the incident and exit surfaces of the lens, the total luminous flux is divided into multiple sub-fluxes, and then the light-receiving surface is divided into multiple regions of equal area, meaning that the luminous flux in each region is the same, which can improve the uniformity of the light spot on the light-receiving surface. Moreover, this lens can basically focus the light emitted by the light source on the light-receiving surface, especially the light from the edge, which can reduce the light intensity angle by 10%, thereby reducing the UGR value.

[0012] Preferably, step S1 includes the following steps:

[0013] S11: The total luminous flux Φ t The luminous flux is divided into N molecules, each with a luminous flux of Φ. t / N, calculate the luminous flux after the superposition of the luminous fluxes of i molecules as: Where N is a natural number greater than 2, and i = 1, 2, ..., N-1;

[0014] S12: Establish a rectangular coordinate system with the central light source O as the center point. Within the angle range of 0° to 90°, the angle between the corresponding ray region after the superposition of i-molecule luminous flux and the Y-axis is defined as θ. i The value of i varies with the included angle θ i Increasing sequentially, the included angle θ i The luminous flux inside is make equal to Φ i Combined with definite integrals Where I o Calculate Φ, where Φ is the center light intensity of light source O. i The included angle θ i The value;

[0015] S13: According to θ i Find θ i complementary angle β j Where j = Ni, the angle β between the edge of the luminous flux of the j-th molecule closest to the Y-axis and the X-axis is obtained. j .

[0016] Preferably, step S2 includes:

[0017] The light-receiving surface is divided into N-1 regions S of equal area. j S1, S2, ..., S N-1 S N-1 Let S1, S2, ..., S be the circle located at the center. N-2 S is a concentric ring from the outside in. j The radius of the outer circle

[0018] Obtain the distance H from the central light source O to the light receiving surface.

[0019] Preferably, steps S3 and S4 include the following steps:

[0020] Set N-1 points B on bus b j and point B N They are B1, B2, ... B N-1 B N , Where B1 is the starting point on the side furthest from the Y-axis, B N Located on the Y-axis, two adjacent points B j and B j+1 The interval between them constitutes the first segment;

[0021] Set N-1 points C on bus C. j and point C N C1, C2, ... C N-1 C N , Where C1 is the starting point on the side furthest from the Y-axis, C N Located on the Y-axis, two adjacent points C j and C j+1 The interval between these two segments constitutes a second segment.

[0022] Obtain the coordinates of starting points B1 and C1.

[0023] Preferably, step S5 includes the following steps:

[0024] Based on the principle of iteration, and using the known coordinates of the previous point... and Calculate the coordinates of the next point. and The iterative calculation method is as follows:

[0025] S51: From coordinates and get Where H is the distance from the light source O to the light receiving surface, calculate the incident ray OB. j One-way vector Light ray B in the lens j C j unit vector Outgoing ray C j R j unit vector

[0026]

[0027] S52: Calculate the position of the busbar b at point Bj normal vector busbar c at point C j normal vector Where n is the refractive index of the lens, derived from the normal vector. and normal vector Calculate the points B for busbar a and busbar b respectively. j and point C j tangent slope and

[0028] S53: Due to point B j and point B j+1 Existence Relationship By β j+1 Calculate the incident ray OB j+1 slope Combination Find

[0029] S54: Light B j+1 C j+1 The slope is Set a coefficient D, and define the formula. junction point C j and point C j+1 Existence Relationship Calculate

[0030] and

[0031] Preferably, in step S54, the value of the coefficient D is 0. <D<0.6。

[0032] because so If the slope of the outgoing ray from the incident surface is greater than the slope of the incident ray, then the function of the incident surface is to focus the light and distribute the luminous flux appropriately.

[0033] Traditional fitting methods often lead to This results in the incident surface being spherical and lacking a focusing effect, which undoubtedly increases the refraction angle of the outgoing light from the exiting surface. Due to the increased refraction angle of the exiting surface and the limited focusing effect of a single surface, a hook appears at the bottom of the calculated generatrix of the exiting surface, making it impossible for the lens to be properly demolded during manufacturing.

[0034] The technical solution is set up (0 < D < 0.6) This relational expression enables certain light-concentrating effects to occur on both the incident surface and the exit surface without disrupting the original energy relationship distribution, and the designed surface is gentle and easy to process.

[0035] On the other hand, the present invention also proposes a lens formed by applying the above-mentioned method for fitting the generatrix of the lens. By applying the above-mentioned method for fitting the generatrix of the lens, the uniformity of the light spot can be improved and the UGR value can be reduced.

[0036] Preferably, a step is provided on the outer periphery of the lens. The step is provided on the lower sides of the incident surface and the exit surface, and the sub-light flux farthest from the optical axis of the central light source irradiates on the step. The sub-light flux farthest from the optical axis of the central light source irradiates on the step and does not emit outward, so that the outermost sub-light flux with poor color uniformity can be removed.

[0037] On the other hand, the present invention also proposes a lens assembly having the above-mentioned lens. The lens assembly further includes a diffusion cover. The diffusion cover is provided on one side of the lens close to the incident surface. The diffusion cover is used to mix the light rays of different light waves emitted by the light source and emit the light rays to the lens in a Lambertian form. By adopting the above-mentioned lens assembly with the lens, the uniformity of the light spot can be improved and the UGR value can be reduced.

[0038] As is well known, the light source emits light with different wavelengths, and the refractive indices of light with different wavelengths are different. Due to the difference in refractive index, the light with different wavelengths will produce certain dispersion after passing through the lens, resulting in uneven color on the light receiving surface. Currently, the main way to solve the problem of color mixing of light with different wavelengths is to set the incident surface of the lens as a matte surface. Although the matte surface can achieve the effect of color mixing, the light rays will produce strong Gaussian scattering after passing through the matte surface, and the light at the edge is very strong, resulting in an increase in the UGR value.

[0039] This technical solution sets a diffusion cover. The diffusion cover can mix the light rays of different wavelengths of the light source, making the finally emitted light rays have uniform color. Moreover, the light rays are nearly Lambertian scattered after passing through the diffusion cover, and the light at the edge is weak, further reducing the UGR value.

[0040] Preferably, the diffusion cover is made of a mixture of PC and a light diffusing agent. Description of the Drawings

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative efforts.

[0042] Figure 1 A grayscale image showing the lighting effect using existing lenses;

[0043] Figure 2 Color diagram of the lighting effect using existing lenses;

[0044] Figure 3 This is a schematic diagram of the lens assembly structure of the present invention, and a schematic diagram of the fitting method for the generatrix of the lens;

[0045] Figure 4 This is a grayscale image of the lighting effect in Embodiment 1 of the present invention;

[0046] Figure 5 This is a color diagram of the lighting effect in Embodiment 1 of the present invention.

[0047] In the attached diagram: 1-light source, 2-diffuser cover, 3-lens, 31-incident surface, 32-outceasing surface, 33-step.

[0048] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0049] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0050] It should be noted that if the embodiments of the present invention involve directional indicators, such as up, down, left, right, front, back, etc., the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0051] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0052] like Figure 3 As shown, a method for fitting the generatrix of a lens 3 is described. The lens 3 includes an incident surface 31 and an exit surface 32. The method for fitting the generatrix b of the incident surface 31 and the generatrix c of the exit surface includes the following steps:

[0053] S1: Obtain the total luminous flux of the central light source, divide the total luminous flux into multiple sub-luminous fluxes, and calculate the angle corresponding to each sub-luminous flux.

[0054] S2: Divide the light receiving surface into multiple concentric illumination areas of equal area, calculate the radius of each concentric area, and obtain the distance from the central light source to the light receiving surface;

[0055] S3: Divide busbar b into multiple first segments and busbar c into multiple second segments, so that the multiple sub-light fluxes, multiple first segments, multiple second segments and multiple irradiation areas correspond one-to-one;

[0056] S4: Obtain the coordinates of the starting points of busbar b and busbar c;

[0057] S5: Based on the angle, the radius, the distance, and the starting point coordinates, and according to the iteration principle, calculate the endpoint coordinates of the next first segment and the next second segment from the known endpoint coordinates of the previous first segment and the known endpoint coordinates of the previous second segment;

[0058] S6: Connect the endpoints of the multiple first segments sequentially to fit a bus line b, and connect the endpoints of the multiple second segments sequentially to fit a bus line c.

[0059] When fitting the incident surface 31 and the exit surface 32 of the lens, the total luminous flux is divided into multiple sub-fluxes, and then the light receiving surface is divided into multiple regions of equal area, that is, the luminous flux in each region is the same, which can improve the uniformity of the light spot on the light receiving surface. Moreover, this lens can basically focus the light emitted from the central light source on the light receiving surface, especially the light from the edge is also basically focused on the light receiving surface, which can reduce the light intensity angle by 10%. Especially for lamps with a large emission angle, it can reduce the light intensity of the edge light and reduce the UGR value.

[0060] In some specific embodiments, step S1 includes the following steps:

[0061] S11: The total luminous flux Φ t The luminous flux is divided into N molecules, each with a luminous flux of Φ. t / N, calculate the luminous flux after the superposition of the luminous fluxes of i molecules as: Where N is a natural number greater than 2, and i = 1, 2, ..., N-1;

[0062] S12: Establish a rectangular coordinate system with the central light source O as the center point. Within the angle range of 0° to 90°, the angle between the corresponding ray region after the superposition of i-molecule luminous flux and the Y-axis is defined as θ. i included angle θ i This reflects the angle corresponding to the sub-light flux, where the value of i varies with the included angle θ. i The angle increases sequentially, meaning θ1 is the angle between the luminous flux of the i=1th component, measured from one side of the Y-axis. When i=3, the angle θ3 represents the angle between the superposition of the luminous flux of the i=1th, i=2nd, and i=3rd components. i The luminous flux inside is make equal to Φ i Combined with definite integrals Where I o Calculate Φ based on the central light intensity of the central light source O. i The included angle θ i The value;

[0063] S13: According to θ i Find θ i complementary angle β j ,Right now Where j = Ni, that is, j is calculated from the side closest to the X-axis, and the angle β between the edge of the luminous flux of the j-th molecule closest to the Y-axis and the X-axis is obtained. j .

[0064] Step S2 includes:

[0065] The light-receiving surface is divided into N-1 regions S of equal area. j S1, S2, ..., S N-1 S N-1 Let S1, S2, ..., S be the circle located at the center. N-2 S is a concentric ring from the outside in. j The radius of the outer circle Obtain the distance H from the central light source O to the light receiving surface.

[0066] Specifically, each equal portion of the sub-light flux is projected onto each region of equal area, while the light emitted by the central light source O at θ i Light rays at angles close to 90°, i.e., the Nth (j=1)th sub-brush flux, have very poor color uniformity. Therefore, on the side of generatrix b and c away from the Y-axis, starting from the i=N-1th sub-brush flux, i.e., the j=2th sub-brush flux, a step 33 can be set below the incident surface 31 and the exit surface 32. The j=1th sub-brush flux illuminates the step and does not radiate outwards, thus creating regions S1 to S... N-1Each component corresponds one-to-one with the luminous flux of the i=N-1 to i=1 components, thus removing the luminous flux of the Nth (j=1) component with poor color uniformity.

[0067] Steps S3 and S4 include the following steps:

[0068] Set N-1 points B on bus b j and point B N They are B1, B2, ... B N-1 B N , Where B1 is the starting point on the side furthest from the Y-axis, B N Located on the Y-axis, two adjacent points B j and B j+1 The first segment consists of B1 and B2, which are the two endpoints of the first segment closest to the X-axis. The first segment corresponds to the luminous flux of the i = N-1 (j = 2)th molecule. B2 and B3 are the two endpoints of the second segment closest to the X-axis, and so on. The busbar b is at point B. N The slope of the tangent line is 0.

[0069] Set N-1 points C on bus C. j and point C N C1, C2, ... C N-1 C N , Where C1 is the starting point on the side furthest from the Y-axis, C N Located on the Y-axis, two adjacent points C j and C j+1 The interval between these points constitutes a second segment, where C1 and C2 are the two endpoints of the first second segment on the side closest to the X-axis. The first second segment corresponds to the luminous flux of the i = N-1 (j = 2)th molecule. C2 and C3 are the two endpoints of the second second segment on the side closest to the X-axis, and so on. The generatrix c is located at point C. N The slope of the tangent line is 0.

[0070] Obtain the coordinates of starting points B1 and C1.

[0071] Step S5 includes the following steps:

[0072] Based on the principle of iteration, and using the known coordinates of the previous point... and Calculate the coordinates of the next point. and The iterative calculation method is as follows:

[0073] S51: From coordinates and get Where H is the distance from the light source O to the light receiving surface, calculate the incident ray OB. j One-way vector Light ray B in the lens j C j unit vector Outgoing ray C j R j unit vector

[0074]

[0075] S52: Calculate the position of the busbar b at point B j normal vector busbar c at point C j normal vector Where n is the refractive index of the lens, derived from the normal vector. and normal vector Calculate the points B for busbar a and busbar b respectively. j and point C j tangent slope and

[0076] S53: Due to point B j and point B j+1 Existence Relationship By β j+1 Calculate the incident ray OB j+1 slope Combination Find

[0077] S54: Light B j+1 C j+1 The slope is Set a coefficient D, and define the formula. junction point C j and point C j+1 Existence Relationship Calculate

[0078] and

[0079] Further, in step S54, the value of the coefficient D is 0. <D<0.6。

[0080] because so If the slope of the outgoing ray from the incident surface is greater than the slope of the incident ray, then the function of the incident surface is to focus the light and distribute the luminous flux appropriately.

[0081] Traditional fitting methods often cause This makes the incident surface a spherical surface and does not produce a light-concentrating effect. Undoubtedly, this will increase the refraction angle of the outgoing light rays of the outgoing surface. Due to the need to increase the refraction angle of the outgoing surface and the limited light-concentrating effect of a single surface, barbs appear at the bottom of the generatrix of the calculated outgoing surface, which makes it impossible to normally eject the mold during the processing of the lens.

[0082] In this technical solution, the setting of (0 < D < 0.6) This relationship makes the incident surface and the outgoing surface produce a certain light-concentrating effect without destroying the original energy relationship distribution, and the designed surface is gentle and easy to process.

[0083] On the other hand, a lens formed by applying the generatrix fitting method of the above lens. By applying the generatrix fitting method of the above lens, the lens can improve the uniformity of the light spot and reduce the UGR value.

[0084] Furthermore, a step is provided on the outer periphery of the lens 3. The step 33 is provided on the lower sides of the incident surface 31 and the outgoing surface 32. The sub-light flux farthest from the optical axis of the central light source irradiates on the step 33. The sub-light flux farthest from the optical axis of the central light source, that is, the Nth (j = 1) sub-light flux, irradiates on the step and does not emit outward, and can remove the outermost sub-light flux with poor color uniformity.

[0085] On the other hand, a lens assembly having the above lens. The lens assembly further includes a diffusion cover 2. The diffusion cover 2 is provided on the side of the lens 3 close to the incident surface 31. The diffusion cover 2 is used to mix the light rays of different light waves emitted by the light source 1 and emit the light rays to the lens 3 in the form of Lambert. By adopting the lens assembly of the above lens, the uniformity of the light spot can be improved and the UGR value can be reduced.

[0086] As is well known, the light source 1 emits light with different wavelengths, and the refractive indices of light with different wavelengths are different. Due to the difference in refractive indices, the light with different wavelengths will produce a certain chromatic dispersion after passing through the lens, resulting in a phenomenon of uneven color on the light receiving surface. At present, the main way to solve the problem of color mixing of light with different wavelengths is to set the incident surface of the lens as a matte surface. Although the matte surface can achieve the effect of color mixing, the light will produce strong Gaussian scattering after passing through the matte surface, and the light at the edge is very strong, resulting in an increase in the UGR value.

[0087] This technical solution sets a diffusion cover 2. The diffusion cover 2 can mix the light rays of different wavelengths of the light source 1 to make the finally emitted light rays have uniform color. Moreover, the light is nearly Lambert scattering after passing through the diffusion cover 2, and the light at the edge is weak, further reducing the UGR value.

[0088] Furthermore, the diffusion cover 2 is a mixture of PC and a light diffusing agent. Specifically, the light diffusing agent can be an organic light diffusing agent such as acrylic, styrene, or acrylic resin.

[0089] The following tests and comparisons are conducted on different downlights.

[0090] Comparative Example 1: Using an existing lens for testing, with the light-receiving surface 1 meter away from the light source, the 10% intensity angle of the light was measured to be 133.61°, and the lighting effect was as follows. Figure 1 and Figure 2 It can be seen that the light spot of the existing lens is not evenly dispersed, and the light at the edge is strong.

[0091] Example 1:

[0092] The downlight in Example 1 uses the diffuser cover and lens combination of this technical solution. The UGR value test results are shown in Table 1 below. The illumination effect at a distance of 1 meter from the light receiving surface is as follows: Figure 4 and Figure 5 .

[0093] Table 1

[0094]

[0095] As shown in Table 1, the UGR value of the light emitted by the downlight in Example 1 is less than 19 on different types of light receiving surfaces, light receiving surfaces of the same type but different reflectivities, and when the tester observes from different positions in space. The difference from 19 is significant, and in some test positions it can be reduced to below 16.

[0096] In this embodiment, the 10% intensity angle of the light was measured to be 71.58°, which is significantly reduced by 10% compared to Comparative Example 1. Figure 1 and Figure 2 ,and Figure 4 and Figure 5 The comparison shows that the light spot is evenly distributed on the light receiving surface, and very little light is scattered to the edge, which effectively reduces the UGR value and makes people feel more comfortable.

[0097] Example 2:

[0098] The light source and lens of the downlight in Example 2 are the same as those in Example 1. The difference is that Example 2 does not use a diffuser cover, but sets the incident surface of the lens to a frosted surface. The UGR value test results are shown in Table 2 below:

[0099] Table 2

[0100]

[0101] A comparison of Tables 1 and 2 shows that when the diffuser cover is not used and the incident surface of the lens is set to a frosted surface, the UGR value is greater than 19 at most test locations, and even close to or greater than 21 at many locations. The UGR value is high and the human comfort is low. The diffuser cover has a better effect on reducing the UGR value.

[0102] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A method of fitting a lens (3) comprising an entrance surface (31) and an exit surface (32), characterized in that, The fitting method of the generatrix b of the incident curved surface (31) and the generatrix c of the exit curved surface (32) comprises the following steps: S1: obtaining the total luminous flux of the central light source, dividing the total luminous flux into multiple sub-luminous fluxes, and calculating the angles corresponding to the sub-luminous fluxes; S2: dividing the light receiving surface into multiple irradiation areas with equal areas and concentric, calculating the radii of each of the concentric irradiation areas, and obtaining the distance from the central light source to the light receiving surface; S3: dividing the generatrix b into multiple first segments and dividing the generatrix c into multiple second segments, so that the multiple sub-luminous fluxes, the multiple first segments, the multiple second segments and the multiple irradiation areas correspond one by one; S4: obtaining the starting point coordinates of the generatrix b and the generatrix c; S5: according to the angles corresponding to the sub-luminous fluxes, the radii of the concentric irradiation areas, the distance from the central light source to the light receiving surface, and the starting point coordinates of the generatrix b and the generatrix c, according to the iteration principle, the end point coordinates of the next first segment and the end point coordinates of the next second segment are calculated from the known end point coordinates of the previous first segment and the known end point coordinates of the previous second segment; S6: fitting the end points of the multiple first segments into the generatrix b by connecting them in sequence, and fitting the end points of the multiple second segments into the generatrix c by connecting them in sequence; The step S1 comprises the following steps: S11: obtaining the total light flux Φ t The total light flux Φ is divided into N parts, and each part is Φ t / N, and the light flux after superposition of i parts is Φ where N is a natural number greater than 2, and i = 1, 2,..., N-1. S12: Establish a rectangular coordinate system with the central light source O as the center point. Within the angle range of 0° to 90°, the angle between the corresponding ray region after the superposition of i-molecule luminous flux and the Y-axis is defined as θ. i The value of i varies with the included angle θ i Increasing sequentially, the included angle θ i The luminous flux inside is make equal to Φ i Combined with definite integrals Where I o Calculate Φ based on the center light intensity of light source O. i The included angle θ i The value; S13: According to θ i , the complementary angle β j of θ i is calculated, where j = N - i, and the included angle β j of the edge line close to the Y axis of the jth partial light flux to the X axis is obtained; The step S2 comprises: The light-receiving surface is divided into N-1 regions S of equal area. j S1, S2, ..., S N-1 S N-1 Let S1, S2, ..., S be the circle located at the center. N-2 S is a concentric ring from the outside in. j The radius of the outer circle Obtaining the distance H from the central light source O to the light receiving surface; The steps S3 and S4 comprise the following steps: N-1 points B are set on the bus bar b j and the points B N , respectively, B1, B2,... B N-1 , B N , wherein B1 is the starting point away from the Y-axis side, B N is located on the Y-axis, and the first segment is between the adjacent two points B j and B j+1 ; N-1 points C are set on the bus c j and the points C N , respectively C1, C2,... C N-1 , C N , wherein C1 is the starting point away from the Y-axis, C N is located on the Y-axis, and the two adjacent points C j and C j+1 are one of the second segments; Obtaining the coordinate values of the starting points B1 and C1; The step S5 comprises the following steps: According to the iterative principle, the coordinates of the next point are calculated from the known coordinates of the previous point and the coordinates of the next point and are calculated iteratively as follows: S51: Obtain the unit vector of the incident light ray OB and Find the unit vector of the incident light ray OB j Find the unit vector of the light ray B j C j in the lens Find the unit vector of the emergent light ray C j R j ​​​ S52: Calculate the normal vector of the generatrix b at point B j S53: Calculate the normal vector of the generatrix c at point C j where n is the refractive index of the lens, the tangent slopes of the generatrix a and the generatrix b at points B and C j j and ​​​​​ S53: due to point B j and point B j+1 there is a relationship calculated from β j+1 the slope of the incident light ray OB j+1 in combination found ​ S54: light ray B j+1 C j+1 The slope of the line is A coefficient D is set, D > 0, and the formula The point C j And the point C j+1 There is a relationship Calculated and 2. The lens' generatrix fitting method of claim 1, wherein, In the step S54, the size of the coefficient D is 0<D<0.

6.

3. A lens characterized by, The lens is formed by applying the generatrix fitting method of the lens according to claim 1 or 2.

4. The lens of claim 3, wherein, The outer periphery of the lens (3) is further provided with a step (33), and the step (33) is arranged on the lower side of the incident curved surface (31) and the exit curved surface (32), and the sub-luminous flux farthest from the optical axis of the central light source is irradiated on the step (33).

5. A lens assembly characterized by, The lens assembly comprises the lens according to claim 3 or 4, and the lens assembly further comprises a diffusion cover (2), the diffusion cover (2) is arranged on the side of the lens (3) close to the incident curved surface (31), and the diffusion cover (2) is used for mixing light rays of different light waves emitted by the light source and emitting light rays in the form of Lambert to the lens (3).

6. The lens assembly of claim 5, wherein, The diffusion cover (2) is a mixed material of PC and light diffuser.

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