Four-part optical lens with large aperture

Abstract

A four-part optical lens with a large aperture, comprising a first lens (10) with a positive light focus, a second lens (20) with a negative light focus, a third lens (30) with a positive light focus, and a fourth lens (40) with a positive light focus, arranged sequentially, characterized in that the two surfaces of the first lens (10) are each an S1 surface (11) and an S2 surface (12), wherein the two surfaces of the second lens (20) are each an S3 surface (21) and an S4 surface (22), wherein the two surfaces of the third lens (30) are each an S5 surface (31) and an S6 surface (32), wherein the two surfaces of the fourth lens (40) are each an S7 surface (41) and an S8 surface (42), wherein the S1 surface (11), the S2 surface (12), the S3 surface (21), S4 surface (22), S5 surface (31), S6 surface (32), S7 surface (41) and S8 surface (42) are arranged one after the other,wherein the side of the S8 surface (42) facing away from the S7 surface (41) is provided with an S9 surface (50), wherein an aperture diaphragm (60) is arranged on one side of the S1 surface (11) or between the S2 surface (12) and the S3 surface (21), wherein the S7 surface (41) is provided with a vignetting diaphragm (70), wherein the S1 surface (11), the S2 surface (12), the S5 surface (31), the S6 surface (32) and the S7 surface (41) are convex surfaces, wherein the S4 surface (22) is a concave surface, , where the distance between the aperture stop (60) and the object focus of the lens |ST - F obj | is, where the equivalent focal length of the lens is f0, |ST - F obj | < 0.7f0, where the free aperture d of the S1 surface (11) to the S8 surface (42) satisfies the following relationship: d i > 0.9d j , i < j, where i is an integer from 1 to 7 and j is an integer from 2 to 8, wherein the radius of curvature of the S3 surface (21) is r3, wherein the radius of curvature of the S4 surface (22) is r4, |r4| < |r3|, wherein the radius of curvature of the S7 surface (41) is r7, wherein the radius of curvature of the S8 surface (42) is r8, |r7| < |r8|, wherein the equivalent focal length of the fourth lens (40) is greater than the equivalent focal length of the third lens (30), wherein the equivalent focal length of the fourth lens (40) is greater than the equivalent focal length of the first lens (10), where the center distance between the S6 surface (32) and the S7 surface (41) G 67 is, where the center distance between the S2 surface (12) and the S3 surface (21) G 23 is, G 67 < G 23 .

Description

Technical field

[0001] The present invention relates to the technical field of optical lenses, in particular to a four-part optical lens with a large aperture. State of the art

[0002] In conventional technology, the vehicle headlight lens consists of a light source, a light energy collecting element, a light-dark boundary line structure and a convex lens, based on the projection principle.

[0003] The newly developed pixel headlights are also called matrix headlights. They utilize digital light projection technology, allowing the vehicle headlights to not only provide illumination but also project patterns onto the ground, such as weather conditions, road navigation information, or other symbols that can be identified by people outside the vehicle. The optical system of the pixel headlight primarily comprises luminescent pixels (e.g., mini-LEDs, microLEDs, LCD screens, LCOS, or illuminated DMD digital micromirrors) and optical projection lenses. For the projection pattern to be clearly visible, the lens must achieve high optical performance: various optical aberrations, such as chromatic aberrations, field curvature, and astigmatism, are eliminated.

[0004] State-of-the-art optical lenses must combine multiple positive and negative lenses in a suitable manner to eliminate aberrations. The number of lenses used depends on the lens parameters, performance indicators, and the optical materials and processes employed. More complex optical lenses may contain more than 10 lenses. Currently, optical lenses used in mobile phones typically contain more than 6 lenses, and their cost is high.

[0005] The image quality of the three-part Cook lens using conventional technology can hardly meet the requirements. Fig.Figure 1 shows a classic four-element, three-set Tessar lens. This lens evolved from the three-element Cook lens; that is, the final set of monoconvex lenses is a double-bonded lens. The Tessar lens produces sharp images and corrects well for a wide range of aberrations. However, the numerical aperture of the original design is small, generally only about 0.125 and no more than 0.2, which means that the light energy utilization rate is extremely low, the lens arrangement requires very precise adjustments, the tolerance rate is small, and the usage requirements are high. Therefore, the four-element, double-Gauss lens also suffers from the aforementioned problems.

[0006] Pixel headlights fulfill both illumination and imaging functions: On the one hand, higher energy efficiency and brightness are required; on the other hand, the projected image places specific demands on image quality, particularly low chromatic aberration. Furthermore, due to the specific characteristics of automotive applications, optical lenses must exhibit higher thermal reliability, improved vibration resistance, and reduced weight to further enhance market competitiveness while simultaneously demanding lower costs.

[0007] State-of-the-art optical lenses cannot simultaneously meet performance requirements such as high energy utilization rate, high image quality, simple and stable structure, and low cost.

[0008] US 20030161051 A1 discloses a single-focus lens consisting of four lens components arranged from the object side in the order of positive, negative, positive, and relatively weak positive or negative refractive power, with an aperture positioned between the first and second lens components. The third lens component has a convex surface on its image side, and the fourth lens component has a meniscus shape, at least one aspherical surface, and is concave on its image side. The second lens component consists of a single lens element. Content of the present invention

[0009] To solve the problems of the prior art, the present invention provides a four-part optical lens with a large aperture. The four-part optical lens has a high energy utilization rate, high image quality, a simple and stable structure, and low production and operating costs.

[0010] A four-part optical lens with a large aperture according to the present invention, comprising a first lens with a positive light focus, a second lens with a negative light focus, a third lens with a positive light focus, and a fourth lens with a positive light focus, arranged one after the other, wherein the two surfaces of the first lens are each an S1 surface and an S2 surface, wherein the two surfaces of the second lens are each an S3 surface and an S4 surface, wherein the two surfaces of the third lens are each an S5 surface and an S6 surface, wherein the two surfaces of the fourth lens are each an S7 surface and an S8 surface, wherein the S1 surface, the S2 surface, the S3 surface, the S4 surface, the S5 surface, the S6 surface, the S7 surface, and the S8 surface are arranged one after the other, wherein the side facing away from the S7 surface of the The S8 surface is equipped with an S9 surface.wherein an aperture diaphragm is arranged on one side of the S1 surface or between the S2 surface and the S3 surface, wherein the S7 surface is provided with a vignetting diaphragm, wherein the S1 surface, the S2 surface, the S5 surface, the S6 surface and the S7 surface are convex surfaces, wherein the S4 surface is a concave surface, where the distance between the aperture stop and the object focus of the lens |ST - F obj | is, where the equivalent focal length of the lens is f0, |ST - F obj | < 0.7f0, where the free aperture d of the S1 surface up to the S8 surface satisfies the following relationship: d i > 0.9d j , i < j, where i is an integer from 1 to 7 and j is an integer from 2 to 8, wherein the radius of curvature of the S3 surface is r3, wherein the radius of curvature of the S4 surface is r4, |r4| < |r3|, wherein the radius of curvature of the S7 surface is r7, wherein the radius of curvature of the S8 surface is r8, |r7| < |r8|, wherein the equivalent focal length of the fourth lens is greater than the equivalent focal length of the third lens, wherein the equivalent focal length of the fourth lens is greater than the equivalent focal length of the first lens, where the center distance between the S6 surface and the S7 surface G 67 is where the center distance between the S2 surface and the S3 surface G 23 is, G 67 < G 23 .

[0011] Preferably, the rear intersection point of the lens is larger than 2 mm.

[0012] Preferably, the S8 surface is provided to be a flat surface or a concave surface.

[0013] Preferably, the S1 surface, the S2 surface, the S3 surface, the S4 surface, the S5 surface, the S6 surface, the S7 surface and the S8 surface are spherical or aspherical.

[0014] Preferably, the first lens, the second lens, the third lens and the fourth lens are single lenses or adhesive lenses.

[0015] Preferably, the first lens, the second lens, the third lens and the fourth lens are glass lenses or plastic lenses.

[0016] Furthermore, it is provided that the Abbe number of the first lens is Vd1, the Abbe number of the second lens is Vd2, the Abbe number of the third lens is Vd3, the Abbe number of the fourth lens is Vd4, Vd1 - Vd2 > 25, Vd3 - Vd2 > 25, Vd4 - Vd2 > 25.

[0017] The advantageous effects of the present invention: The present invention discloses a four-part optical lens with a large aperture. Only four lenses are used in the lens, resulting in low manufacturing costs, a simple and stable overall structure, good vibration damping, and low lens weight. When assembling each lens, the sensitivity to axial tolerances is low, the tolerance rate is high, assembly is easy, and assembly costs are low. When applied to a projection imaging system, the energy utilization rate can be improved by increasing the numerical aperture, thereby effectively enhancing the brightness of the light distribution. The optical lens exhibits good dispersion performance and high image resolution, i.e., high image quality. Brief description of the drawing Fig.Figure 1 is a schematic diagram of the structure of the lens system of the Tessar lens. Fig. Figure 2 is a schematic diagram of the structure of embodiment 1 according to the present invention. Fig. Figure 3 is an astigmatism and field curvature curve diagram and a distortion curve diagram of embodiment 1 according to the present invention. Fig. Figure 4 is a curve diagram of the axial chromatic aberration of embodiment 1 according to the present invention. Fig. Figure 5 is an MTF curve diagram of embodiment 1 according to the present invention. Fig. Figure 6 is a schematic diagram of the structure of embodiment 2 according to the present invention. Fig. Figure 7 is an astigmatism and field curvature curve diagram and a distortion curve diagram of embodiment 2 according to the present invention. Fig.Figure 8 is a curve diagram of the axial chromatic aberration of embodiment 2 according to the present invention. Fig. Figure 9 is an MTF curve diagram of embodiment 2 according to the present invention.

[0018] Reference symbols: First lens 10, S1 area 11, S2 area 12, Second lens 20, S3 area 21, S4 area 22, Third lens 30, S5 area 31, S6 area 32, Fourth lens 40, S7 area 41, S8 area 42, S9 area 50, Aperture diaphragm 60, Vignetting diaphragm 70. Detailed descriptions

[0019] In order to further understand the features, technical means and specific purposes and functions of the present invention, the present invention is described in detail in combination with the drawings and specific embodiments. Referring to Figures 1 to 9.

[0020] A four-part large-aperture optical lens according to a basic embodiment of the present invention, comprising a first lens 10 with a positive light focus, a second lens 20 with a negative light focus, a third lens 30 with a positive light focus, and a fourth lens 40 with a positive light focus, arranged sequentially along the direction of incidence of the light, wherein the two surfaces of the first lens 10 are each an S1 surface 11 and an S2 surface 12, wherein the two surfaces of the second lens 20 are each an S3 surface 21 and an S4 surface 22, wherein the two surfaces of the third lens 30 are each an S5 surface 31 and an S6 surface 32, wherein the two surfaces of the fourth lens 40 are each an S7 surface 41 and an S8 surface 42, wherein the S1 surface 11, the S2 surface 12, the S3 area 21, S4 area 22, S5 area 31, S6 area 32,The S7 surface 41 and the S8 surface 42 are arranged sequentially along the direction of light incidence, wherein the side of the S8 surface 42 facing away from the S7 surface 41 is provided with an S9 surface 50, wherein the S9 surface 50 is an image surface, i.e., the S9 surface 50 is located in the image focus of the entire optical lens, wherein an aperture diaphragm 60 is arranged on one side of the S1 surface 11 or between the S2 surface 12 and the S3 surface 21, wherein the aperture diaphragm 60 is ideally located on the side of the S1 surface 11 facing away from the S2 surface 12, and wherein the aperture diaphragm 60 is positioned between the S2 surface 12 and the S3 surface 21, taking into account the design requirements when applied to a vehicle headlight lens can be adjusted, whereby the structural body of the aperture diaphragm 60 can be hidden inside the lens, so that the structural body of the aperture diaphragm 60 is not observed outside the vehicle headlight lens,wherein the S7 surface 41 is provided with a vignetting aperture 70, wherein the vignetting aperture 70 is generally a lens frame, wherein the S1 surface 11, the S2 surface 12, the S5 surface 31, the S6 surface 32 and the S7 surface 41 are convex surfaces, wherein the S4 surface 22 is a concave surface, where the distance between the aperture diaphragm 60 and the object focus of the entire optical lens |ST - F obj | is, where ST represents the distance between the aperture stop 60 and the center of the entire optical lens, F objrepresents the distance between the object focus of the entire optical lens and the center of the entire optical lens, where the equivalent focal length of the entire optical lens is f0, and where the aperture diaphragm 60 is located near the object focus of the entire optical lens, since in practical application the object focus of the entire optical lens may lie within the first lens 10, i.e., the following formula is satisfied: |ST - F obj | < 0.7f0, where the free aperture d1 to d8 of the S1 surface 11 to the S8 surface 42 satisfies the following relationship: d i > 0.9d j , i < j, where i takes on an integer from 1 to 7 and j takes on an integer from 2 to 8, where d is the free aperture of the corresponding optical surface along the direction of incidence of the light, where the change in caliber of the S1 surface 11 to the S8 surface 42 basically corresponds to the trend of gradual decrease, wherein the radius of curvature of the S3 surface is 21 r3, wherein the radius of curvature of the S4 surface is 22 r4, |r4| < |r3|, wherein the radius of curvature of the S7 surface is 41 r7, wherein the radius of curvature of the S8 surface is 42 r8, |r7| < |r8|, wherein the equivalent focal length of the fourth lens 40 is greater than the equivalent focal length of the third lens 30, namely f4 > f3, wherein the equivalent focal length of the fourth lens 40 is greater than the equivalent focal length of the first lens 10, namely f4 > f1. where the center distance between the S6 surface is 32 and the S7 surface is 41 G 67 is, where the center distance between the S2 surface 12 and the S3 surface 21 G 23 is, G 67 < G 23 .

[0021] During operation, the light successively reaches S1 surface 11, S2 surface 12, S3 surface 21, S4 surface 22, S5 surface 31, S6 surface 32, S7 surface 41, S8 surface 42, and S9 surface 50. The optical lens of the present invention can significantly improve the dispersion performance of the vehicle headlight and reduce its sensitivity to axial tolerances during lens assembly, resulting in high assembly error tolerance and low assembly difficulty.

[0022] The Tessar lens is based on the classic three-part Cook design, as in Fig.Figure 1 shows that, generally, the aperture diaphragm is located at the intermediate lens, allowing common aberrations such as field curvature, astigmatism, chromatic aberrations, etc., to be reduced or corrected through structural symmetry. However, the use of this structure results, on the one hand, in a small numerical aperture for describing the overall light energy utilization rate, and on the other hand, it also leads to a large angle of incidence (CRA) of the principal beam for the image area of ​​the large field of view. The light intensity of a general light source corresponds to Lambert's cosine law. The light intensity is highest at the 0-degree position, decreases to 0.5 at the 60-degree position, and to 0 at the 90-degree position. Since the angle of incidence (CRA) is larger, this means that the lens system can receive less energy for the same solid angles.

[0023] In the present invention, the aperture diaphragm 60 is arranged at the object focus of the optical lens to form an image-side telecentric beam path, such that the principal rays of each field of view are parallel, i.e., the angle of incidence CRA of the principal ray of each field of view at the image surface (S9-surface 50) is 0. This means that the energy utilization rate of the present invention is higher for equal solid angles. In practical applications, the aperture diaphragm 60 is arranged near the object focus of the optical lens. The angle of incidence of the principal ray of each field of view at the image surface (S9-surface 50) is less than 20°, and the energy utilization rate is high.

[0024] According to the present embodiment, the rear intersection point of the optical lens is greater than 2 mm, i.e., the distance between the S8 surface 42 and the S9 surface 50 is greater than 2 mm. Since the light source generates some heat during operation, the optical lens with four lenses and a sufficiently large rear intersection point can effectively prevent problems such as heat-induced part deformation.

[0025] According to the present embodiment, the S8 surface 42 is provided to be a flat surface or a concave surface.

[0026] According to the present embodiment, it is provided that the S1 surface 11, the S2 surface 12, the S3 surface 21, the S4 surface 22, the S5 surface 31, the S6 surface 32, the S7 surface 41 and the S8 surface 42 are spherical or aspherical, i.e., the S1 surface 11 to the S8 surface 42 can be spherical surfaces, or the S1 surface 11 to the S8 surface 42 can be aspherical surfaces, or the S1 surface 11 to the S8 surface 42 have one spherical surface and one aspherical surface, wherein the aspherical surface is a rational design surface.

[0027] According to the present embodiment, the first lens 10, the second lens 20, the third lens 30, and the fourth lens 40 are either single lenses or bonded lenses. That is, the first lens 10, the second lens 20, the third lens 30, and the fourth lens 40 can be single lenses, or they can be bonded lenses, or they can each consist of one single lens and one bonded lens. The bonded lens, also known as an achromatic lens, is formed by bonding two single lenses together, which significantly improves the performance of multicolor imaging compared to the performance of a single lens.

[0028] According to the present embodiment, the first lens 10, the second lens 20, the third lens 30 and the fourth lens 40 are glass lenses or plastic lenses, i.e. the first lens 10, the second lens 20, the third lens 30 and the fourth lens 40 can be glass lenses, or the first lens 10, the second lens 20, the third lens 30 and the fourth lens 40 can be plastic lenses, or the first lens 10, the second lens 20, the third lens 30 and the fourth lens 40 have one glass lens and one plastic lens.

[0029] According to the present embodiment, the Abbe number of the first lens is 10 Vd1, the Abbe number of the second lens is 20 Vd2, the Abbe number of the third lens is 30 Vd3, the Abbe number of the fourth lens is 40 Vd4, Vd1 - Vd2 > 25, Vd3 - Vd2 > 25, Vd4 - Vd2 > 25.

[0030] In embodiment 1, the optical lens structure is in Fig.2 shown, and the optical lens is arranged according to Tables 1, 2, 3 and 4 below. Table 1. Parameters of each surface in embodiment 1 Area number Surface type Radius of curvature r (mm) Thickness (mm) Refractive index n AbbezahlVd free aperture d Property area Spherical surface Endless 25000 Aperture stop Spherical surface Endless 0,00 41,88 S1 Aspherical surface 46,83 15,42 1,492 57,98 41,89 S2 Aspherical surface -10,40 4,50 41,08 S3 Aspherical surface 20,42 2,43 1,584 27,86 30,35 S4 Aspherical surface 4,62 6,56 25,75 S5 Spherical surface 20,99 13,80 1,487 70,42 26,50 S6 Spherical surface -30,17 0,09 25,59 S7 Spherical surface 17,96 11,24 1,755 52,30 20,65 S8 Spherical surface 54,09 4,31 14,42 S9 Spherical surface Endless 0,00 10,00

[0031] The expression for the aspherical surface is as follows: z=cr21+1−(1+k)c2r2+Ar4+Br6+Cr8+Dr10+Er12+Fr14+Gr16+Hr18+Jr20

[0032] where z is the vector height of the r-position on the aspherical surface, c is the paraxial curvature of the aspherical surface, c = 1 / r, r is the radius of curvature, k is the cone coefficient, and AJ is the higher-order term coefficient. Table 2. Parameters of each aspherical surface in embodiment 1 S1 S2 S3 S4 Cone coefficient 0 -4,932 -8,84E-01 -1,77E+00 A -1,90E-05 1,10E-05 -1,07E-04 5,28E-06 B 9,32E-08 -4,95E-08 3,52E-07 1,25E-07 C -3,69E-10 6,47E-11 -6,71E-10 -6,40E-10 D 6,38E-13 4,00E-16 3,73E-13 8,26E-13 E -3,68E-16 0 0 0 0 for all other higher-order terms Table 3. Design parameters of the optical lens in embodiment 1 parameter Equivalent focal length f0 (mm) f1(mm) f2(mm) f3(mm) f4(mm) Rear Intersection f / EPD Numerical Aperture NA 1 / 2FOV(°) Numerical value 28,3 19,00 -10,81 27,85 31,41 4,30 0,67 0,74 10,0 Table 4. Restriction relationship in embodiment 1 Restriction relationship Result |ST-F obj |<0,7 f0 |ST-F obj |=12.81 mm, therefore fulfills free aperture d i >0.9d j As shown in Table 1, fulfills S7 surface with vignetting aperture Vignetting coefficient for 1 / 2 FOV 0.45 |r4|<|r3| As shown in Table 1, fulfills r4<0 As shown in Table 1, fulfills f4>f3 As shown in Table 3, fulfills f4>f1 As shown in Table 3, fulfills |r7|<|r8| As shown in Table 1, fulfills G 67 <G 23 As shown in Table 1, fulfills Rear intersection point larger than 2 mm From Table 3, the rear intersection point is known to be 4.3 mm, fulfilling

[0033] In summary, it can be seen that the numerical aperture in embodiment 1 reaches 0.74, which is much larger than the 0.125 of the Tessar lens, thus significantly improving the energy utilization rate. The astigmatism and field curvature curves and distortion curves in embodiment 1 are shown in Fig. Figure 3 shows the axial chromatic aberration curve. Fig. Figure 4 shows the MTF (Modulation Transfer Function) curve. Fig. Figure 5 shows that the optical lens exhibits good image quality when applied to the projection imaging system.

[0034] In embodiment 2, the optical lens structure is in Fig. 6 shown, and the optical lens is arranged according to Tables 5, 6, 7 and 8 below. Table 5. Parameters of each surface in embodiment 2 Area number Surface type Radius of curvature r (mm) Thickness (mm) Refractive index n AbbezahlVd Caliber size d Property area Spherical surface Endless 25000 S1 Aspherical surface 42,622 8,510 1,492 57,98 28,93 S2 (aperture aperture) Aspherical surface -12,870 7,441 28,16 S3 Aspherical surface -115,860 2,390 1,584 27,86 20,16 S4 Aspherical surface 4,641 2,626 18,30 S5 Aspherical surface 7,185 9,354 1,586 60,60 19,07 S6 Aspherical surface -22,594 1,789 17,65 S7 Spherical surface 11,890 5,613 1,755 52,30 12,47 S8 Spherical surface 20,294 3,115 9,74 S9 Spherical surface Endless 0,00 7,99

[0035] The expression for the aspherical surface is as follows: z=cr21+1−(1+k)c2r2+Ar4+Br6+Cr8+Dr10+Er12+Fr14+Gr16+Hr18+Jr20

[0036] where z is the vector height of the r-position on the aspherical surface, c is the paraxial curvature of the aspherical surface, c = 1 / r, r is the radius of curvature, k is the cone coefficient, and AJ is the higher-order term coefficient. Table 6. Parameters of each aspherical surface in embodiment 2 S1 S2 S3 S4 S5 S6 control coefficient k -7,17110872 -5,588 9,36E+00 -2,54E+00 -2,88 -25,40 A 3,56E-06 2,36E-06 7,44E-05 8,32E-05 6,35E-05 -2,22E-04 B -8,65E-08 -2,25E-08 -1,42E-06 5,47E-07 1,04E-06 3,70E-06 C 2,83E-10 -8,74E-11 1,14E-08 -4,13E-08 -8,28E-09 -1,79E-08 D -6,66E-13 2,12E-13 -1,02E-10 2,43E-10 0E+00 0,00E+00 E 0,00E+00 0E+00 4,73E-13 0E+00 0E+00 0E+00 0 for all other higher-order terms Table 7. Design parameters of the optical lens in embodiment 2 parameter Equivalent focal length f0 (mm) f1(mm) f2(mm) f3(mm) f4(mm) Rear Intersection f / EPD Numerical Aperture NA 1 / 2FOV(°) Numerical value 18,89 21,10 -7,51 10,49 29,41 3,12 0,67 0,75 12,0 Table 8. Restriction relationship in embodiment 2 Restriction relationship Result |ST-F obj |<0,7 f0 |ST-F obj |=6.62 mm, therefore fulfills free aperture d i >0.9d j As shown in Table 5, fulfills S7 surface with vignetting aperture Vignetting coefficient for 1 / 2 FOV 0.72 |r4|<|r3| As shown in Table 5, fulfills r4<0 As shown in Table 5, fulfills f4>f3 As shown in Table 7, fulfills f4>f1 As shown in Table 7, fulfills |r7|<|r8| As shown in Table 5, fulfills G 67 <G 23 As shown in Table 5, fulfills Rear intersection point larger than 2 mm From Table 7, the rear intersection point is known to be 3.12 mm, which fulfills the requirements.

[0037] In summary, it can be seen that the numerical aperture in embodiment 2 reaches 0.75, which is much larger than the 0.125 of the Tessar lens, thus significantly improving the energy utilization rate. The astigmatism and field curvature curves and distortion curves in embodiment 2 are shown in Fig. 7 shown.

[0038] The curve of axial chromatic aberration is in Fig. Figure 8 shows the MTF (Modulation Transfer Function) curve. Fig. Figure 9 shows that the optical lens exhibits good image quality when applied to the projection imaging system.

[0039] The exemplary embodiments mentioned above merely express several embodiments of the present invention, and their description is more specific and detailed, but should not be understood as limiting the scope of the patent for the present invention. It should be noted that, for a person skilled in the art, several modifications and improvements could be made without departing from the concept of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention takes precedence over the appended claims.

Claims

[1] Four-part large aperture optical lens comprising a first lens (10) with positive light focus, a second lens (20) with negative light focus, a third lens (30) with positive light focus and a fourth lens (40) with positive light focus arranged one after the other, characterized by, that the two surfaces of the first lens (10) are each an S1 surface (11) and an S2 surface (12), wherein the two surfaces of the second lens (20) are each an S3 surface (21) and an S4 surface (22), wherein the two surfaces of the third lens (30) are each an S5 surface (31) and an S6 surface (32), wherein the two surfaces of the fourth lens (40) are each an S7 surface (41) and an S8 surface (42), wherein the S1 surface (11), the S2 surface (12), the S3 surface (21), the S4 surface (22), the S5 surface (31), the S6 surface (32), the S7 surface (41) and the S8 surface (42) are arranged sequentially, wherein the side of the S8 surface (42) facing away from the S7 surface (41) is provided with an S9 surface (50), wherein an aperture diaphragm (60) is arranged on one side of the S1 surface (11) or between the S2 surface (12) and the S3 surface (21), wherein the S7 surface (41) is provided with a vignetting diaphragm (70), wherein the S1 surface (11), the S2 surface (12),the S5 surface (31), the S6 surface (32) and the S7 surface (41) are convex surfaces, while the S4 surface (22) is a concave surface. where the distance between the aperture stop (60) and the object focus of the lens |ST - F obj | is, where the equivalent focal length of the lens is f0, |ST - F obj | < 0.7f0, where the free aperture d of the S1 surface (11) to the S8 surface (42) satisfies the following relationship: d i > 0.9d j , i < j, where i is an integer from 1 to 7 and j is an integer from 2 to 8, wherein the radius of curvature of the S3 surface (21) is r3, wherein the radius of curvature of the S4 surface (22) is r4, |r4| < |r3|, wherein the radius of curvature of the S7 surface (41) is r7, wherein the radius of curvature of the S8 surface (42) is r8, |r7| < |r8|, wherein the equivalent focal length of the fourth lens (40) is greater than the equivalent focal length of the third lens (30), wherein the equivalent focal length of the fourth lens (40) is greater than the equivalent focal length of the first lens (10), where the center distance between the S6 surface (32) and the S7 surface (41) G 67 is, where the center distance between the S2 surface (12) and the S3 surface (21) G 23 is, G 67 < G 23 . [2] Four-part optical lens with large aperture according to claim 1, characterized by that the rear intersection point of the lens is larger than 2 mm. [3] Four-part optical lens with large aperture according to claim 1, characterized by, that the S8 surface (42) is a flat surface or a concave surface. [4] Four-part optical lens with large aperture according to claim 1, characterized by , that the S1 surface (11), the S2 surface (12), the S3 surface (21), the S4 surface (22), the S5 surface (31), the S6 surface (32), the S7 surface (41) and the S8 surface (42) are spherical or aspherical. [5] Four-part optical lens with large aperture according to claim 1, characterized by , that the first lens (10), the second lens (20), the third lens (30) and the fourth lens (40) are single lenses or adhesive lenses. [6] Four-part optical lens with large aperture according to claim 1, characterized by , that the first lens (10), the second lens (20), the third lens (30) and the fourth lens (40) are glass lenses or plastic lenses. [7] Four-part optical lens with large aperture according to claim 1, characterized by, that the Abbe number of the first lens (10) is Vd1, where the Abbe number of the second lens (20) is Vd2, where the Abbe number of the third lens (30) is Vd3, where the Abbe number of the fourth lens (40) is Vd4, Vd1 - Vd2 > 25, Vd3 - Vd2 > 25, Vd4 - Vd2 > 25.

Images