Day and night confocal optical system and camera module

Abstract

The application discloses a day and night confocal optical system and a camera module. The day and night confocal optical system comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens which are sequentially arranged along an optical axis from an object plane to an image plane. The lenses of the optical system satisfy the following conditions: -15 < f1 < -8; -7.5 < f2 < -3.6; -9.3 < f3 < 11; -11.5 < f4 < 4.3; 1 < f5 < 5; -3.5 < f6 < 3.3; -5.6 < f7 < 4.9. The day and night confocal optical system is configured by seven lenses, the number of lenses is reasonable, the structure is simple, the optical power of each lens is reasonably distributed, the lens aberration is optimized, the imaging quality of the optical system is improved, the day and night confocal optical system and the camera module have excellent resolving power, high pixels, a large aperture, day and night confocal and other excellent characteristics, and have great potential in the IPC market.

Description

Technical Field

[0001] This invention relates to the field of optical lens technology, and more particularly to a day / night confocal optical system and a camera module. Background Technology

[0002] With the advancement of science and technology and the development of society and the economy, camera lenses are widely used in various fields, especially in the field of security monitoring. However, previous camera lenses or optical systems have shortcomings such as low pixel count, small field of view, poor day and night performance, and low light intake, which make it difficult to meet the needs of users. Summary of the Invention

[0003] The purpose of this invention is to provide a day-night confocal optical system to solve the defects of current camera lenses, such as low pixel count, small field of view, poor day-night performance, and low light intake.

[0004] This invention is achieved through the following technical solution: The day-night confocal optical system includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens arranged sequentially along the optical axis from the object plane to the image plane; The object plane side of the first lens is convex, and the image plane side is concave, and its optical power is negative. The object side of the second lens is convex, and the image side is concave, and its optical power is negative. The optical power of the third lens is either positive or negative; The optical power of the fourth lens is either positive or negative; The fifth lens has a convex object plane and a convex image plane, and its optical power is positive. The optical power of the sixth lens is either positive or negative; The image plane side of the seventh lens is convex, and its optical power can be positive or negative. Each lens in this optical system satisfies the following condition: -15 < f1 < -8; -7.5 < f2 < -3.6; -9.3 < f3 < 11; -11.5 < f4 < 4.3; 1 < f5 < 5; -3.5 < f6 < 3.3; -5.6 < f7 < 4.9; Wherein, f1 is the focal length of the first lens, f2 is the focal length of the second lens, f3 is the focal length of the third lens, f4 is the focal length of the fourth lens, f5 is the focal length of the fifth lens, f6 is the focal length of the sixth lens, and f7 is the focal length of the seventh lens.

[0005] Furthermore, the optical system satisfies: TTL < 23 mm, where TTL is the on-axis distance from the object side of the first lens to the imaging plane.

[0006] Furthermore, each lens in this optical system satisfies the following condition: 1.60<Nd1<2.02, 15<Vd1<65; 1.50<Nd2<1.65, 50<Vd2<58; 1.53<Nd3<1.75, 18<Vd3<23; 1.43<Nd4<2.05, 13<Vd4<56; 1.45<Nd5<1.95, 50<Vd5<83; 1.43<Nd6<1.68, 18<Vd6<56; 1.43<Nd7<1.68, 18<Vd7<56; Nd1 is the refractive index of the first lens, and Vd1 is the Abbe number of the first lens; Nd2 is the refractive index of the second lens, and Vd2 is the Abbe number of the second lens; Nd3 is the refractive index of the third lens, and Vd3 is the Abbe number of the third lens; Nd4 is the refractive index of the fourth lens, and Vd4 is the Abbe number of the fourth lens; Nd5 is the refractive index of the fifth lens, and Vd5 is the Abbe number of the fifth lens; Nd6 is the refractive index of the sixth lens, and Vd6 is the Abbe number of the sixth lens; Nd7 is the refractive index of the seventh lens, and Vd7 is the Abbe number of the seventh lens.

[0007] Furthermore, the fourth lens is a glass spherical lens or a plastic aspherical lens.

[0008] Furthermore, an aperture stop is provided between the fourth lens and the fifth lens.

[0009] Furthermore, the fifth lens and the sixth lens are bonded together to form a combined lens.

[0010] Furthermore, the optical system satisfies: 180°≤FOV≤ 200°, where FOV is the field of view angle in the diagonal direction.

[0011] Furthermore, the optical system satisfies: f ≤ 2mm, where f is the effective focal length of the optical system.

[0012] Furthermore, the maximum image circle satisfies: MIC ≥ 4.1 mm.

[0013] To address the shortcomings of current camera lenses, such as low pixel count, narrow field of view, poor day and night performance, and low light intake, this invention provides a day and night confocal optical system. Correspondingly, a camera module is provided, which includes at least an optical lens, and the aforementioned day and night confocal optical system is installed within the optical lens.

[0014] The advantage of this technical solution lies in the fact that by configuring the day and night confocal optical system with 7 lenses, the number of lenses is reasonable and the structure is simple. By rationally allocating the optical power of each lens, the lens aberration is optimized and the imaging quality of the optical system is improved. This gives the day and night confocal optical system and camera module excellent characteristics such as resolution, high pixel count, large aperture, and day and night confocality, and it has great potential in the IPC market. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] To more clearly illustrate the technical solution in Embodiment 1 of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below.

[0017] Figure 1 This is a schematic diagram of the day-night confocal optical system in Embodiment 1 of the present invention; Figure 2 This is a graph showing the astigmatism and distortion curves of the day-night confocal optical system in Embodiment 1 of the present invention; Figure 3 This is the visible light MTF curve of the day-night confocal optical system in Embodiment 1 of the present invention; Figure 4 This is a schematic diagram of the day-night confocal optical system in Embodiment 2 of the present invention; Figure 5 This is a graph showing the astigmatism and distortion curves of the day-night confocal optical system in Embodiment 2 of the present invention; Figure 6 This is the visible light MTF curve of the day-night confocal optical system in Embodiment 2 of the present invention; Figure 7 This is a schematic diagram of the day-night confocal optical system in Embodiment 3 of the present invention; Figure 8 This is a graph showing the astigmatism and distortion curves of the day-night confocal optical system in Embodiment 3 of the present invention; Figure 9 This is the visible light MTF curve of the day-night confocal optical system in Embodiment 3 of the present invention. Detailed Implementation

[0018] 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 some embodiments of the present invention, and not all 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.

[0019] Example 1: As Figure 1-3 As shown, the camera module includes at least an optical lens (not shown in the figure), and a day-night confocal optical system is installed inside the optical lens. The day-night confocal optical system includes a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a fifth lens 5, a sixth lens 6 and a seventh lens 7 arranged sequentially along the optical axis from the object plane to the image plane. An aperture stop 8 is provided between the fourth lens 4 and the fifth lens 5, and a color filter 9 is provided next to the image plane of the seventh lens 7. The object plane side of the first lens 1 is convex, and the image plane side is concave, and its optical power is negative. The object plane side of the second lens 2 is convex, and the image plane side is concave, and its optical power is negative. The optical power of the third lens 3 is either positive or negative; The optical power of the fourth lens 4 is either positive or negative; The object plane side of the fifth lens 5 is convex, the image plane side is convex, and its optical power is positive. The optical power of the sixth lens 6 is either positive or negative; The image plane side of the seventh lens 7 is convex, and its optical power is either positive or negative; Each lens in this optical system satisfies the following condition: -15 < f1 < -8; -7.5 < f2 < -3.6; -9.3 < f3 < 11; -11.5 < f4 < 4.3; 1 < f5 < 5; -3.5 < f6 < 3.3; -5.6 < f7 < 4.9; Wherein, f1 is the focal length of the first lens 1, f2 is the focal length of the second lens 2, f3 is the focal length of the third lens 3, f4 is the focal length of the fourth lens 4, f5 is the focal length of the fifth lens 5, f6 is the focal length of the sixth lens 6, and f7 is the focal length of the seventh lens 7.

[0020] Among them, constraining f1 within a large negative optical power range effectively reduces astigmatism and field curvature of the optical system; By constraining f2, f3, f4, f5, f6, and f7 within a reasonable range, the spherical aberration of the optical system can be finely adjusted and controlled, effectively improving the imaging quality of the optical system.

[0021] In summary, this invention provides a day-night confocal optical system and camera module to address the shortcomings of current camera lenses, such as low pixel count, small field of view, poor day-night performance, and low light intake. The main improvement is achieved by configuring the day-night confocal optical system with seven lenses, resulting in a reasonable number of lenses, a simple structure, and optimized lens aberrations through reasonable allocation of the optical power of each lens. This enhances the imaging quality of the optical system, giving it excellent resolution, high pixel count, large aperture, and day-night confocal capabilities, making it a promising candidate in the IPC market.

[0022] In Embodiment 1 of the present invention, each lens of the optical system satisfies the following conditions: 1.60<Nd1<2.02, 15<Vd1<65; 1.50<Nd2<1.65, 50<Vd2<58; 1.53<Nd3<1.75, 18<Vd3<23; 1.43<Nd4<2.05, 13<Vd4<56; 1.45<Nd5<1.95, 50<Vd5<83; 1.43<Nd6<1.68, 18<Vd6<56; 1.43<Nd7<1.68, 18<Vd7<56; Wherein, Nd1 is the refractive index of the first lens 1, and Vd1 is the Abbe number of the first lens 1; Nd2 is the refractive index of the second lens 2, and Vd2 is the Abbe number of the second lens 2; Nd3 is the refractive index of the third lens 3, and Vd3 is the Abbe number of the third lens 3; Nd4 is the refractive index of the fourth lens 4, and Vd4 is the Abbe number of the fourth lens 4; Nd5 is the refractive index of the fifth lens 5, and Vd5 is the Abbe number of the fifth lens 5; Nd6 is the refractive index of the sixth lens 6, and Vd6 is the Abbe number of the sixth lens 6; Nd7 is the refractive index of the seventh lens 7, and Vd7 is the Abbe number of the seventh lens 7.

[0023] The above configuration effectively reduces chromatic aberration and optimizes lens aberration by constraining the refractive index and Abbe number of the first lens 1, second lens 2, third lens 3, fourth lens 4, fifth lens 5, sixth lens 6 and seventh lens 7 within a reasonable range, thereby improving the imaging quality of the optical system.

[0024] In Embodiment 1 of this invention, the fourth lens 4 is a glass spherical lens or a plastic aspherical lens. This configuration effectively improves the temperature shift of the optical system under high and low temperatures.

[0025] In Embodiment 1 of this invention, the optical system satisfies the following conditions: TTL < 23mm, 180° ≤ FOV ≤ 200°. Here, TTL is the axial distance from the object-side surface of the first lens 1 to the imaging plane, and FOV is the diagonal field of view. This configuration effectively reduces the overall length of the optical system, miniaturizes the lens, and simultaneously increases the system's information capacity.

[0026] In Embodiment 1 of this invention, the maximum image circle satisfies: MIC ≥ 4.1 mm. This setting helps improve the resolution of the optical system and meets the user's needs.

[0027] In Embodiment 1 of the present invention, the optical system satisfies the condition: f ≤ 2mm. Here, f is the effective focal length of the optical system. This configuration effectively expands the field of view of the optical system.

[0028] Specifically, in Embodiment 1 of the present invention: The effective focal length of the optical system is f = 1.36 mm; The focal length of the first lens 1 is f1 = -13.19 mm; The focal length of the second lens 2 is f2 = -4.8mm; The focal length of the third lens 3 is f3 = 8.97mm; The focal length of the fourth lens 4 is f4 = -8.09mm; The focal length of the fifth lens 5 is f5 = 4.95mm; The focal length of the sixth lens 6 is f6 = 3.19mm; The focal length of the seventh lens 7 is f7 = -5.18mm; Total optical length TTL = 21.5mm; FOV=185°; The maximum image circle MIC = 4.2; The surface type, radius of curvature, thickness, refractive index, and Abbe number of each lens are shown in Table 1.

[0029] Table 1 Face number Surface type Radius of curvature (mm) Thickness (mm) Refractive index Abbe number OBJ - Infinity Infinity S1 spherical 14.310 1.770 1.69 55.5 S2 spherical 5.326 2.979 S3 aspherical 30.000 1.035 1.54 55.71 S4 aspherical 2.348 2.194 S5 aspherical -107.358 1.877 1.66 20.37 S6 aspherical -5.718 0.648 S7 aspherical -2.417 1.039 1.54 55.71 S8 aspherical -6.261 1.632 STO spherical Infinity -0.064 S9 spherical 6.562 2.022 1.49 81.6 S10 spherical -3.560 0.060 S11 aspherical 10.162 1.931 1.54 55.71 S12 aspherical -1.931 0.600 1.66 20.37 S13 aspherical -4.905 1.045 S14 Infinity 0.600 1.51 64.19 S15 Infinity 2.129 IMA - Infinity - In Table 1, the distance from the object plane to the image plane along the optical axis is: OBJ is the object surface; S1 is the object plane of the first lens 1, and S2 is the image plane of the first lens 1; S3 is the object plane of the second lens 2, and S4 is the image plane of the second lens 2; S5 is the object plane of the third lens 3, and S6 is the image plane of the third lens 3; S7 is the object plane of the fourth lens 4, and S8 is the image plane of the fourth lens 4; STO is the location of aperture 8; S9 is the object plane of the fifth lens 5, and S10 is the image plane of the fifth lens 5. S11 is the object plane of the sixth lens 6, and S12 is the image plane of the sixth lens 6; S12 is the object plane of the seventh lens 7, and S13 is the image plane of the seventh lens 7; S14 is the object plane of color filter 9, and S15 is the image plane of color filter 9; IMA stands for Image Plane.

[0030] The aspherical surface types in Table 1 can, but are not limited to, satisfy the following aspherical formulas:

[0031] Where x is the distance from the corresponding point on the aspherical surface to the plane tangent to the vertex of the surface, h is the distance from the corresponding point on the aspherical surface to the optical axis, c is the curvature of the vertex of the aspherical surface, k is the conic coefficient, Ai is the coefficient of the higher-order term of the i-th term, and N is the highest order of the aspherical polynomial, which is the maximum index value of Ai. For example, when N=8, the formula contains 8 correction terms A1, A2, ..., A8. The higher the highest order N, the more refined the surface description and the stronger the ability to correct aberrations.

[0032] The values ​​of the conic coefficients and the coefficients Ai of the higher-order terms of the i-th term for each aspherical surface are shown in Table 2.

[0033] Table 2 Serial Number K A4 A6 A8 A10 A12 A14 A16 S3 0.000 1.54E-02 -3.07E-03 2.90E-04 -1.60E-05 5.30E-07 -9.90E-09 8.04E-11 S4 -1.172 3.48E-02 -1.03E-03 -1.85E-03 3.25E-04 -6.15E-06 -3.06E-06 2.50E-07 S5 0.000 4.57E-03 -2.97E-03 5.43E-04 -2.60E-04 7.09E-05 -8.24E-06 3.43E-07 S6 0.967 8.69E-03 -4.54E-03 6.93E-04 7.03E-05 -3.46E-05 3.98E-06 -1.60E-07 S7 -0.101 4.39E-02 -1.25E-02 5.72E-03 -1.65E-03 3.18E-04 -3.76E-05 2.12E-06 S8 -10.709 2.23E-02 -5.19E-03 5.27E-03 -3.38E-03 1.45E-03 -3.38E-04 3.23E-05 S11 -12.253 -2.15E-03 -4.22E-04 -2.52E-04 1.55E-04 -5.62E-05 1.07E-05 -1.07E-06 S12 -0.333 1.58E-02 -4.53E-03 3.66E-03 -2.02E-03 6.69E-04 -1.22E-04 1.03E-05 S13 2.009 4.39E-03 -9.93E-04 3.94E-04 -1.54E-04 3.78E-05 -4.78E-06 2.57E-07 in, Figure 2 The astigmatism and distortion curves of Example 1 are shown. Astigmatism represents the curvature of the meridional image plane and the curvature of the sagittal image plane, and distortion represents the magnitude of distortion at different image heights. Figure 3 The visible light MTF curve of Example 1 is shown.

[0034] Depend on Figure 2 and Figure 3 It can be seen that the day-night confocal optical system given in Example 1 has good imaging quality and excellent imaging performance.

[0035] Example 2: Figure 4-6 As shown, its difference from Example 1 is as follows: The effective focal length of the optical system is f = 1.33 mm; The focal length of the first lens 1 is f1 = -9.02 mm; The focal length of the second lens 2 is f2 = -4.64 mm; The focal length of the third lens 3 is f3 = -6.56mm; The focal length of the fourth lens 4 is f4 = -4.06mm; The focal length of the fifth lens 5 is f5 = 2.77 mm; The focal length of the sixth lens 6 is f6 = -2.23 mm; The focal length of the seventh lens 7 is f7 = 3.53 mm; Total optical length TTL = 22.5mm; FOV=185°; The maximum image circle MIC = 4.2; The surface type, radius of curvature, thickness, refractive index, and Abbe number of each lens are shown in Table 3.

[0036] Table 3 Face number Surface type Radius of curvature (mm) Thickness (mm) Refractive index Abbe number OBJ - Infinity Infinity S1 spherical 15.750 1.928 1.83 42.7 S2 spherical 4.830 4.176 S3 aspherical 15.068 0.800 1.54 55.71 S4 aspherical 2.102 2.284 S5 aspherical -2.893 1.179 1.66 20.37 S6 aspherical -9.872 0.100 S7 spherical 4.361 1.785 1.92 18.9 S8 spherical -23.500 1.650 STO spherical Infinity -0.083 S9 aspherical 5.930 1.255 1.54 55.71 S10 aspherical -1.845 0.610 1.66 20.37 S11 aspherical 8.800 0.449 S12 aspherical 3.913 1.668 1.54 55.71 S13 aspherical -3.145 1.045 S14 Infinity 0.600 1.51 64.19 S15 Infinity 2.052 IMA - Infinity - In Table 3, the distance from the object plane to the image plane along the optical axis is as follows: OBJ is the object surface; S1 is the object plane of the first lens 1, and S2 is the image plane of the first lens 1; S3 is the object plane of the second lens 2, and S4 is the image plane of the second lens 2; S5 is the object plane of the third lens 3, and S6 is the image plane of the third lens 3; S7 is the object plane of the fourth lens 4, and S8 is the image plane of the fourth lens 4; STO is the location of aperture 8; S9 is the object plane of the fifth lens 5, and S10 is the image plane of the fifth lens 5. S10 is the object plane of the sixth lens 6, and S11 is the image plane of the sixth lens 6. S12 is the object plane of the seventh lens 7, and S13 is the image plane of the seventh lens 7; S14 is the object plane of color filter 9, and S15 is the image plane of color filter 9; IMA stands for Image Plane.

[0037] The aspherical surface types in Table 3 can, but are not limited to, satisfy the following aspherical formulas:

[0038] Where x is the distance from the corresponding point on the aspherical surface to the plane tangent to the vertex of the surface, h is the distance from the corresponding point on the aspherical surface to the optical axis, c is the curvature of the vertex of the aspherical surface, k is the conic coefficient, Ai is the coefficient of the higher-order term of the i-th term, and N is the highest order of the aspherical polynomial, which is the maximum index value of Ai. For example, when N=8, the formula contains 8 correction terms A1, A2, ..., A8. The higher the highest order N, the more refined the surface description and the stronger the ability to correct aberrations.

[0039] The values ​​of the conic coefficients and the coefficients Ai of the higher-order terms of the i-th term for each aspherical surface are shown in Table 4.

[0040] Table 4 Serial Number K A4 A6 A8 A10 A12 A14 A16 S3 0.000 -1.87E-04 -2.57E-04 -1.03E-05 2.74E-06 -9.50E-08 0.00E+00 0.00E+00 S4 -0.597 6.03E-03 -2.15E-03 1.66E-03 -8.10E-04 1.97E-04 -2.86E-05 1.97E-06 S5 -0.018 3.08E-02 -1.77E-03 -2.87E-04 1.81E-04 -5.14E-05 8.24E-06 -4.47E-07 S6 6.044 2.06E-02 -9.06E-04 2.13E-04 -1.69E-04 6.05E-05 -9.78E-06 6.69E-07 S9 15.123 -7.00E-03 1.30E-02 -3.93E-02 5.17E-02 -3.88E-02 1.53E-02 -2.51E-03 S10 -0.202 -6.37E-03 3.08E-02 -1.15E-03 -3.67E-02 3.46E-02 -1.45E-02 2.39E-03 S11 0.000 -8.92E-03 1.20E-02 2.86E-03 -1.23E-02 9.27E-03 -3.11E-03 4.05E-04 S12 -9.521 -7.27E-03 5.05E-03 -2.35E-03 3.16E-04 7.45E-05 -3.33E-05 3.37E-06 S13 -0.649 -2.51E-03 -1.31E-03 9.11E-04 -4.76E-04 1.18E-04 -1.51E-05 6.07E-07 in, Figure 5 The astigmatism and distortion curves of Example 2 are shown. Astigmatism represents the curvature of the meridional image plane and the curvature of the sagittal image plane, and distortion represents the magnitude of distortion at different image heights. Figure 6 The visible light MTF curve of Example 2 is shown.

[0041] Depend on Figure 5 and Figure 6 As can be seen, the day-night confocal optical system given in Example 2 has good imaging quality and excellent image quality.

[0042] In Embodiment 2 of the present invention, the fifth lens 5 and the sixth lens 6 are bonded together to form a combined lens. This arrangement effectively improves the chromatic aberration of the optical system.

[0043] Example 3: As Figure 7-9 As shown, its difference from Example 2 is as follows: The effective focal length of the optical system is f = 1.36 mm; The focal length of the first lens 1 is f1 = -10.84mm; The focal length of the second lens 22 is f2 = -6.53mm; The focal length of the third lens 33 is f3 = -4.13mm; The focal length of the fourth lens 44 is f4 = 3.92 mm; The focal length of the fifth lens 55 is f5 = 2.74mm; The focal length of the sixth lens 66 is f6 = -3mm; The focal length of the seventh lens 77 is f7 = 4.82mm; Total optical length TTL=21mm; FOV=185°; The maximum image circle MIC = 4.2; The surface type, radius of curvature, thickness, refractive index, and Abbe number of each lens are shown in Table 5.

[0044] Table 5 Face number Surface type Radius of curvature (mm) Thickness (mm) Refractive index Abbe number OBJ - Infinity Infinity S1 spherical 18.521 1.650 1.69 55.5 S2 spherical 5.186 2.557 S3 aspherical 10.286 0.867 1.54 55.71 S4 aspherical 2.542 3.352 S5 aspherical -2.460 1.374 1.66 20.37 S6 aspherical -27.168 0.100 S7 spherical 4.610 1.789 1.92 18.9 S8 spherical -14.500 1.534 STOP spherical Infinity 0.393 S9 aspherical 9.356 1.414 1.54 55.71 S10 aspherical -1.662 0.600 1.66 20.37 S11 aspherical -11.000 0.070 S12 aspherical 6.700 1.500 1.54 55.71 S13 aspherical -3.902 1.045 S14 Infinity 0.600 1.51 64.19 S15 Infinity 2.153 IMA - Infinity - In Table 5, the distance from the object plane to the image plane along the optical axis is as follows: OBJ is the object surface; S1 is the object plane of the first lens 1, and S2 is the image plane of the first lens 1; S3 is the object plane of the second lens 2, and S4 is the image plane of the second lens 2; S5 is the object plane of the third lens 3, and S6 is the image plane of the third lens 3; S7 is the object plane of the fourth lens 4, and S8 is the image plane of the fourth lens 4; STO is the location of aperture 8; S9 is the object plane of the fifth lens 5, and S10 is the image plane of the fifth lens 5. S10 is the object plane of the sixth lens 6, and S11 is the image plane of the sixth lens 6. S12 is the object plane of the seventh lens 7, and S13 is the image plane of the seventh lens 7; S14 is the object plane of color filter 9, and S15 is the image plane of color filter 9.

[0045] The aspherical surface types in Table 5 can, but are not limited to, satisfy the following aspherical formulas:

[0046] Where x is the distance from the corresponding point on the aspherical surface to the plane tangent to the vertex of the surface, h is the distance from the corresponding point on the aspherical surface to the optical axis, c is the curvature of the vertex of the aspherical surface, k is the conic coefficient, Ai is the coefficient of the higher-order term of the i-th term, and N is the highest order of the aspherical polynomial, which is the maximum index value of Ai. For example, when N=8, the formula contains 8 correction terms A1, A2, ..., A8. The higher the highest order N, the more refined the surface description and the stronger the ability to correct aberrations.

[0047] The values ​​of the conic coefficients and the coefficients Ai of the higher-order terms of the i-th term for each aspherical surface are shown in Table 6.

[0048] Table 6 Serial Number K A4 A6 A8 A10 A12 A14 A16 S3 0.000 9.72E-03 -1.52E-03 1.19E-04 -5.63E-06 1.57E-07 -2.15E-09 9.09E-12 S4 -0.921 1.72E-02 -1.63E-03 1.75E-04 -1.57E-04 4.45E-05 -5.26E-06 2.34E-07 S5 -0.042 2.48E-02 -2.79E-03 1.17E-03 -3.79E-04 1.01E-04 -1.49E-05 1.01E-06 S6 2.824 1.69E-02 -1.24E-03 4.68E-04 -1.76E-04 5.31E-05 -9.58E-06 7.34E-07 S9 11.765 2.39E-03 -1.36E-02 2.81E-02 -3.21E-02 2.05E-02 -6.79E-03 9.13E-04 S10 0.100 2.26E-02 2.42E-02 -3.55E-02 2.74E-02 -6.38E-03 -1.73E-03 8.26E-04 S11 -22.139 1.32E-02 -1.01E-02 4.76E-03 -1.95E-04 -7.01E-04 2.36E-04 -2.33E-05 S12 5.749 8.84E-03 -1.47E-02 9.93E-03 -4.15E-03 9.90E-04 -1.31E-04 7.44E-06 S13 0.000 3.88E-03 -8.74E-04 3.21E-04 -1.52E-04 4.80E-05 -9.72E-06 6.68E-07 in, Figure 8 The astigmatism and distortion curves of Example 3 are shown. Astigmatism represents the curvature of the meridional image plane and the curvature of the sagittal image plane, and distortion represents the magnitude of distortion at different image heights. Figure 9 The visible light MTF curve of Example 3 is shown.

[0049] Depend on Figure 8 and Figure 9 It can be seen that the day-night confocal optical system given in Example 3 has good imaging quality and excellent imaging performance.

[0050] It should be understood that the terms "first," "second," etc., are used in this invention to describe various information, but this information should not be limited to these terms. These terms are only used to distinguish information of the same type from each other. For example, without departing from the scope of this invention, "first" information can also be referred to as "second" information, and similarly, "second" information can also be referred to as "first" information. In addition, the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0051] The above description provides one or more embodiments in conjunction with specific content, and does not imply that the specific implementation of the present invention is limited to these descriptions. Any methods or structures that are similar to or identical to those of the present invention, or any technical deductions or substitutions made based on the concept of the present invention, should be considered as protected by the present invention.

Claims

1. A day-night confocal optical system, characterized in that, It includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens arranged sequentially along the optical axis from the object plane to the image plane; The object plane side of the first lens is convex, and the image plane side is concave, and its optical power is negative. The object side of the second lens is convex, and the image side is concave, and its optical power is negative. The optical power of the third lens is either positive or negative; The optical power of the fourth lens is either positive or negative; The fifth lens has a convex object plane and a convex image plane, and its optical power is positive. The optical power of the sixth lens is either positive or negative; The image plane side of the seventh lens is convex, and its optical power can be positive or negative. Each lens in this optical system satisfies the following condition: -15＜f1＜-8； -7.5＜f2＜-3.6； -9.3＜f3＜11； -11.5＜f4＜4.3； 1＜f5＜5； -3.5＜f6＜3.3； -5.6＜f7＜4.9； Wherein, f1 is the focal length of the first lens, f2 is the focal length of the second lens, f3 is the focal length of the third lens, f4 is the focal length of the fourth lens, f5 is the focal length of the fifth lens, f6 is the focal length of the sixth lens, and f7 is the focal length of the seventh lens.

2. The day-night confocal optical system according to claim 1, characterized in that, The optical system meets the following requirement: TTL < 23mm; Wherein, TTL is the on-axis distance from the object side of the first lens to the imaging plane.

3. The day-night confocal optical system according to claim 1, characterized in that, Each lens in this optical system satisfies the following condition: 1.60<Nd1<2.02, 15<Vd1<65; 1.50<Nd2<1.65, 50<Vd2<58; 1.53<Nd3<1.75, 18<Vd3<23; 1.43<Nd4<2.05, 13<Vd4<56; 1.45<Nd5<1.95, 50<Vd5<83; 1.43<Nd6<1.68, 18<Vd6<56; 1.43<Nd7<1.68, 18<Vd7<56; Nd1 is the refractive index of the first lens, and Vd1 is the Abbe number of the first lens; Nd2 is the refractive index of the second lens, and Vd2 is the Abbe number of the second lens; Nd3 is the refractive index of the third lens, and Vd3 is the Abbe number of the third lens; Nd4 is the refractive index of the fourth lens, and Vd4 is the Abbe number of the fourth lens; Nd5 is the refractive index of the fifth lens, and Vd5 is the Abbe number of the fifth lens; Nd6 is the refractive index of the sixth lens, and Vd6 is the Abbe number of the sixth lens; Nd7 is the refractive index of the seventh lens, and Vd7 is the Abbe number of the seventh lens.

4. The day-night confocal optical system according to any one of claims 1-3, characterized in that, The fourth lens is a glass spherical lens or a plastic aspherical lens.

5. The day-night confocal optical system according to any one of claims 1-3, characterized in that, An aperture stop is provided between the fourth lens and the fifth lens.

6. The day-night confocal optical system according to any one of claims 1-3, characterized in that, The fifth lens and the sixth lens are bonded together to form a combined lens.

7. The day-night confocal optical system according to any one of claims 1-3, characterized in that, The optical system satisfies: 180° ≤ FOV ≤ 200°; Wherein, FOV is the field of view angle in the diagonal direction.

8. The day-night confocal optical system according to any one of claims 1-3, characterized in that, The optical system satisfies: f ≤ 2mm; Where f is the effective focal length of the optical system.

9. The day-night confocal optical system according to any one of claims 1-3, characterized in that, The maximum image circle satisfies: MIC ≥ 4.1 mm.

10. A camera module, comprising at least an optical lens, characterized in that, The optical lens is equipped with a day-night confocal optical system as described in any one of claims 1-9.

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