Day and night confocal optical system and camera module applying same

Abstract

The invention provides a day and night confocal optical system and a camera module using the same, the day and night confocal optical system is mainly composed of seven lenses, the object plane side of the first lens is a convex surface, the image plane side is a concave surface, and the focal power is negative; the object plane side of the second lens is a convex surface, the image plane side is a concave surface, and the focal power is negative; the object plane side of the third lens is a concave surface, the image plane side is a convex surface, and the focal power is positive; the object plane side and the image plane side of the fourth lens are convex surfaces, and the focal power of the fourth lens is positive; the object plane side and the image plane side of the fifth lens are convex surfaces, and the focal power of the fifth lens is positive; the object plane side and the image plane side of the sixth lens are concave surfaces, and the focal power of the sixth lens is negative; the object plane side and the image plane side of the seventh lens are convex surfaces, and the focal power of the seventh lens is positive; the lens is reasonable in number and simple in structure, the imaging quality of an optical system is improved by reasonably distributing the focal power of the lenses and optimizing the aberration of the lens, the characteristics of ultra-wide angle, high illumination, day and night confocal and excellent temperature characteristic are considered, and the lens has huge potential in the IPC market.

Description

Technical Field

[0001] The present application relates to the field of optical imaging, and particularly to a day-night confocal optical system and an imaging module to which the same is applied. Background Art

[0002] With the progress of science and technology and the development of social economy, imaging lenses are widely used in various fields, especially in the field of security monitoring. However, the conventional imaging lenses or optical systems have defects such as low pixel, small field of view angle, poor day-night effect, and small light input, which are difficult to meet the needs of users. Summary of the Invention

[0003] To overcome the technical problems of the existing optical lenses, such as low pixel, small field of view angle, poor day-night effect, and small light input, the present application provides a day-night confocal optical system. By reasonably distributing the surface shape and optical power of each lens, the lens aberration is optimized, and the system has characteristics such as excellent resolution, high pixel, large aperture, athermalization, day-night confocal, and light weight, and has greater competitiveness in the IPC market.

[0004] An optical system is composed of a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens in sequence from the object surface to the image surface along the optical axis: The object surface side of the first lens is convex, and the image surface side is concave, and its optical power is negative; The object surface side of the second lens is convex, and the image surface side is concave, and its optical power is negative; The object surface side of the third lens is concave, and the image surface side is convex, and its optical power is positive; Both the object surface side and the image surface side of the fourth lens are convex, and its optical power is positive; Both the object surface side and the image surface side of the fifth lens are convex, and its optical power is positive; Both the object surface side and the image surface side of the sixth lens are concave, and its optical power is negative; Both the object surface side and the image surface side of the seventh lens are convex, and its optical power is positive.

[0005] Preferably, the lenses of the optical system satisfy the following conditions: -10.5mm < f1 < -6.5mm; -6.1 mm < f2 < -3.9mm; 9.5mm < f3 < 15.5mm; 5.3mm < f4 < 7.5mm; 8.5mm < f5 < 13.5mm; -5.5mm < f6 < -3.9mm; 3.5mm < f7 < 6.5mm; Among them, 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.

[0006] Preferably, each lens of the optical system satisfies the following conditions: Nd1 > 1.51, Vd1 < 65; Nd2 > 1.53, Vd2 < 56; Nd3 > 1.66, Vd3 < 25; Nd4 > 1.47, Vd4 < 85; Nd5 > 1.53, Vd5 < 56; Nd6 > 1.66, Vd6 < 25; Nd7 > 1.53, Vd7 < 56; Among them, Nd1 is the refractive index of the first lens, Vd1 is the Abbe number of the first lens; Nd2 is the refractive index of the second lens, Vd2 is the Abbe number of the second lens; Nd3 is the refractive index of the third lens, Vd3 is the Abbe number of the third lens; Nd4 is the refractive index of the fourth lens, Vd4 is the Abbe number of the fourth lens; Nd5 is the refractive index of the fifth lens, Vd5 is the Abbe number of the fifth lens; Nd6 is the refractive index of the sixth lens, Vd6 is the Abbe number of the sixth lens; Nd7 is the refractive index of the seventh lens, Vd7 is the Abbe number of the seventh lens.

[0007] Preferably, the relative illumination of the maximum field of view of the optical system satisfies: RI ≥ 35%.

[0008] Preferably, the radius of curvature R1 on the object surface side of the first lens satisfies: R1 > 25 mm.

[0009] Preferably, the overall optical length TTL of the optical system satisfies: TTL ≤ 25 mm.

[0010] Preferably, the fourth lens is a glass or plastic lens.

[0011] Preferably, the horizontal field angle FOV of the optical system satisfies: FOV ≥ 185°, and the maximum image circle satisfies: MIC ≥ 5.8 mm.

[0012] Preferably, the aperture stop is arranged between the third lens and the fourth lens.

[0013] Preferably, the fifth lens and the sixth lens are adhesively bonded to form a combined lens.

[0014] On the other hand, an embodiment of the present application further provides an imaging module, which at least includes an optical lens, and the above-mentioned lens optical system is installed in the optical lens.

[0015] Compared with the prior art, the beneficial effects of the present application are as follows: The present invention provides a day-night confocal optical system and an imaging module applying the same, which mainly consists of seven lenses. The object side of the first lens is convex and the image 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 object side of the third lens is concave and the image side is convex, and its optical power is positive; the object side and the image side of the fourth lens are both convex, and its optical power is positive; the object side and the image side of the fifth lens are both convex, and its optical power is positive; the object side and the image side of the sixth lens are both concave, and its optical power is negative; the object side and the image side of the seventh lens are both convex, and its optical power is positive. The number of lens elements is reasonable and the structure is simple. By reasonably distributing the optical power of the lenses and optimizing the lens aberration, the imaging quality of the optical system is improved, and the characteristics of ultra-wide angle, high illuminance, day-night confocal and excellent temperature characteristics are taken into account, having great potential in the IPC market. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments.

[0017] Figure 1 is a schematic structural diagram of the optical system or the imaging module according to Embodiment 1 of the present application; Figure 2 is an astigmatism and distortion curve diagram of the optical system or the imaging module according to Embodiment 1 of the present application; Figure 3 is an MTF curve diagram of the optical system or the imaging module according to Embodiment 1 of the present application; Figure 4 is a schematic structural diagram of the optical system or the imaging module according to Embodiment 2 of the present application; Figure 5 is an astigmatism and distortion curve diagram of the optical system or the imaging module according to Embodiment 2 of the present application; Figure 6 is an MTF curve diagram of the optical system or the imaging module according to Embodiment 2 of the present application; Figure 7 is a schematic structural diagram of the optical system or the imaging module according to Embodiment 3 of the present application; Figure 8 is an astigmatism and distortion curve diagram of the optical system or the imaging module according to Embodiment 3 of the present application; Figure 9 is an MTF curve diagram of the optical system or the imaging module according to Embodiment 3 of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] As Figures 1-9As shown in the figure, the present application provides a day-night confocal optical system, which is composed of a first lens 1, a second lens 2, a third lens 3, a diaphragm 8, a fourth lens 4, a fifth lens 5, a sixth lens 6, a seventh lens 7, an infrared filter 9, and a chip protection glass 10 in sequence along the optical axis from the object plane to the image plane.

[0019] 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 plane side of the second lens is convex, and the image plane side is concave, and its optical power is negative; The object plane side of the third lens is concave, and the image plane side is convex, and its optical power is positive; Both the object plane side and the image plane side of the fourth lens are convex, and its optical power is positive; Both the object plane side and the image plane side of the fifth lens are convex, and its optical power is positive; Both the object plane side and the image plane side of the sixth lens are concave, and its optical power is negative; Both the object plane side and the image plane side of the seventh lens are convex, and its optical power is positive; The present invention provides a day-night confocal optical system and a camera module using the same. The system mainly consists of 7 lenses. The object plane side of the first lens is convex, the image plane side is concave, and its optical power is negative; the object plane side of the second lens is convex, the image plane side is concave, and its optical power is negative; the object plane side of the third lens is concave, the image plane side is convex, and its optical power is positive; both the object plane side and the image plane side of the fourth lens are convex, and its optical power is positive; both the object plane side and the image plane side of the fifth lens are convex, and its optical power is positive; both the object plane side and the image plane side of the sixth lens are concave, and its optical power is negative; both the object plane side and the image plane side of the seventh lens are convex, and its optical power is positive. The number of lenses is reasonable and the structure is simple. By reasonably distributing the optical power of the lenses and optimizing the lens aberrations, the imaging quality of the optical system is improved, and the characteristics of ultra-wide angle, high illumination, day-night confocal, and excellent temperature characteristics are taken into account, having great potential in the IPC market.

[0020] Furthermore, as a preferred embodiment of the present invention rather than a limitation, each lens of the optical system satisfies the following conditions, where 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: -10.5mm < f1 < -6.5mm. This design can make the first lens 1 have a large negative optical power, which is beneficial to reducing the astigmatism and field curvature of the optical system; -6.1 mm < f2 < -3.9mm. By restricting the ratio of the optical power of the second lens 2 to the effective focal length of the optical imaging system within a reasonable range, the spherical aberration of the system is finely adjusted and controlled, thereby effectively improving the imaging quality of the system; 9.5mm < f3 < 15.5mm. By restricting the ratio of the optical power of the third lens 3 to the effective focal length of the optical imaging system within a reasonable range, the optical system has the advantages of ultra-wide angle, large aperture, small size, and excellent temperature characteristics. 5.3mm < f4 < 7.5mm. By restricting the ratio of the optical power of the fourth lens 4 to the effective focal length of the optical imaging system within a reasonable range, the spherical aberration of the system is finely adjusted and controlled, thereby effectively improving the imaging quality of the system. 8.5mm < f5 < 13.5mm. By restricting the ratio of the optical power of the fifth lens 5 to the effective focal length of the optical imaging system within a reasonable range, the optical system has the advantages of ultra-wide angle, large aperture, small size, and excellent temperature characteristics. -5.5mm < f6 < -3.9mm. By restricting the ratio of the optical power of the sixth lens 6 to the effective focal length of the optical imaging system within a reasonable range, the configured optical system has the advantages of ultra-wide angle, small aperture, high illuminance, and excellent temperature characteristics, with a compact structure, being convenient for processing and installation. At the same time, the configuration of a large aperture can increase the light input of the optical system and higher imaging quality.

[0021] 3.5mm < f7 < 6.5mm. By restricting the ratio of the optical power of the seventh lens 7 to the effective focal length of the optical imaging system within a reasonable range, the spherical aberration of the system is finely adjusted and controlled, thereby effectively improving the imaging quality of the system. Furthermore, the refractive index Nd1 and Abbe number Vd1 of the first lens 1 satisfy: Nd1 > 1.51, Vd1 < 65. This design can effectively reduce chromatic aberration, optimize lens aberration, and thereby effectively improve the imaging quality of the system. Furthermore, the refractive index Nd2 and Abbe number Vd2 of the second lens 2 satisfy: Nd2 > 1.53, Vd2 < 56. This design can effectively reduce chromatic aberration, optimize lens aberration, and thereby effectively improve the imaging quality of the system. Furthermore, the refractive index Nd3 and Abbe number Vd3 of the third lens 3 satisfy: Nd3 > 1.66, Vd3 < 25. This design can effectively reduce chromatic aberration, optimize lens aberration, and thereby effectively improve the imaging quality of the system. Furthermore, the refractive index Nd4 and Abbe number Vd4 of the fourth lens 4 satisfy: Nd4 > 1.47, Vd4 < 85. This design can effectively reduce chromatic aberration, optimize lens aberration, and thereby effectively improve the imaging quality of the system. Furthermore, the refractive index Nd5 and Abbe number Vd5 of the fifth lens 5 satisfy: Nd5 > 1.53, Vd5 < 56. This design can effectively reduce chromatic aberration, optimize lens aberration, and thereby effectively improve the imaging quality of the system. Furthermore, the refractive index Nd6 and Abbe number Vd6 of the sixth lens 6 satisfy: Nd6 > 1.66, Vd6 < 25. This design can effectively reduce chromatic aberration, optimize lens aberration, and thus effectively improve the imaging quality of the system; Furthermore, the refractive index Nd7 and Abbe number Vd7 of the seventh lens 7 satisfy: Nd7 > 1.53, Vd7 < 56. This design can effectively reduce chromatic aberration, optimize lens aberration, and thus effectively improve the imaging quality of the system; Furthermore, as a preferred embodiment of the present invention rather than a limitation, the relative illumination of the maximum field of view of the optical system satisfies: RI ≥ 35%. By controlling the relative illumination, the brightness of the lens edge field of view can be improved; Furthermore, as a preferred embodiment of the present invention rather than a limitation, the curvature radius R1 of the object surface side of the first lens satisfies: R1 > 25 mm. By controlling the object surface side of the first lens 1, the total deflection angle of the object surface of the first lens 1 at the edge field of view can be reasonably controlled within a reasonable range.

[0022] Furthermore, as a preferred embodiment of the present invention rather than a limitation, the fourth lens is made of glass, which can effectively improve the focus shift amount at high and low temperatures.

[0023] Furthermore, as a preferred embodiment of the present invention rather than a limitation, the overall optical length TTL of the optical system satisfies: TTL ≤ 25 mm. This design can reduce the overall optical length and effectively miniaturize the lens.

[0024] Furthermore, as a preferred embodiment of the present invention rather than a limitation, the horizontal field of view FOV of the optical system satisfies: FOV ≥ 185°, and the maximum image circle satisfies: MIC ≥ 5.8 mm, which is beneficial to expanding the field of view and meeting the user's usage requirements; Furthermore, as a preferred embodiment of the present invention rather than a limitation, the fifth lens and the sixth lens are adhesively bonded to form a combined lens. This design increases the difference between the refractive index and Abbe number of the lens and can effectively reduce chromatic aberration.

[0025] Specifically, as a preferred embodiment of the present invention rather than a limitation, as Figures 1-3 shown, in this Embodiment 1, the focal length f1 of the first lens 1 = -9.1 mm, the focal length f2 of the second lens 2 = -5.91 mm, the focal length f3 of the third lens 3 = 13.51 mm, the focal length f4 of the fourth lens 4 = 6.76 mm, the focal length f5 of the fifth lens 5 = 9.1 mm, the focal length f6 of the sixth lens 6 = -4.03 mm, the focal length f7 of the seventh lens 7 = 4.76 mm, the overall optical length TTL = 24 mm. The surface type, curvature radius, thickness, and material parameters of each lens are shown in Table 1: Table 1: Basic parameters of the optical system in Embodiment 1

[0026] In Table 1 above, along the optical axis from the object plane to the image plane, OBJ is the object plane; S1 and S2 correspond to the two surfaces of the first lens 1; S3 and S4 correspond to the two surfaces of the second lens 2; S5 and S6 correspond to the two surfaces of the third lens 3; S8 and S9 correspond to the two surfaces of the fourth lens 4; S10 and S11 correspond to the two surfaces of the fifth lens 5; S12 and S13 correspond to the two surfaces of the sixth lens 6, S13 and S14 correspond to the two surfaces of the seventh lens 7; STO is the position of the aperture stop; S15 and S16 correspond to the two surfaces of the filter; S17 and S18 correspond to the two surfaces of the chip protection glass; IMA corresponds to the image plane.

[0027] Furthermore, in Table 1, for any one of the second lens 2, the third lens 3, the fifth lens 5, the sixth lens 6, and the seventh lens 7, both the object side and the image side are aspherical surfaces. The surface profiles of the aspherical lenses can be defined by, but are not limited to, the following aspherical formula:

[0028] Where x is the distance from the corresponding point on the aspherical surface to the plane tangent to the surface vertex, h is the distance from the corresponding point on the aspherical surface to the optical axis, c is the curvature of the aspherical vertex, k is the conic coefficient, and Ai is the coefficient corresponding to the i-th high-order term in the aspherical surface profile formula. Table 2 gives the conic coefficients and the high-order term coefficients A4, A6, A8, A10, A12, A14, A16, A18, and A20 for the aspherical surfaces that can be used in Embodiment 1.

[0029] Table 2: Aspherical-related numerical values of the lens surfaces in Embodiment 1

[0030] Figure 2 Shows the astigmatism and distortion curves of the optical imaging lens in Embodiment 1. Astigmatism represents the curvature of the meridional image plane and the sagittal image plane, and distortion represents the distortion magnitude values corresponding to different image heights; Figure 3 Shows the MTF curve of the optical imaging lens in Embodiment 1, which represents the MTF values in the meridional direction and the sagittal direction at different spatial frequencies and different fields of view. It can be seen from Figure 2 and Figure 3 that the optical imaging system given in Embodiment 1 can achieve good imaging quality and has higher imaging quality.

[0031] Specifically, as a preferred implementation manner of the present invention rather than a limitation, such as Figures 4-6As shown, in this Embodiment 2, the focal length f1 of the first lens 1 is -8.93 mm, the focal length f2 of the second lens 2 is -4.99 mm, the focal length f3 of the third lens 3 is 10.98 mm, the focal length f4 of the fourth lens 4 is 6.3 mm, the focal length f5 of the fifth lens 5 is 10.8 mm, the focal length f6 of the sixth lens 6 is -3.94 mm, the focal length f6 of the seventh lens 7 is 4.49 mm, the overall optical length TTL is 24 mm, and the surface type, radius of curvature, thickness, and material parameters of each lens are shown in Table 3 as follows: Table 3: Basic parameters of the optical system in Embodiment 2

[0032] In the above Table 3, along the optical axis from the object plane to the image plane, OBJ is the object plane; S1 and S2 correspond to the two surfaces of the first lens 1; S3 and S4 correspond to the two surfaces of the second lens 2; S5 and S6 correspond to the two surfaces of the third lens 3; S8 and S9 correspond to the two surfaces of the fourth lens 4; S10 and S11 correspond to the two surfaces of the fifth lens 5; S12 and S13 correspond to the two surfaces of the sixth lens 6, S13 and S14 correspond to the two surfaces of the seventh lens 7; STO is the position of the aperture stop; S15 and S16 correspond to the two surfaces of the filter; S17 and S18 correspond to the two surfaces of the chip protection glass; IMA corresponds to the image plane.

[0033] Further, in Table 3, for any one of the second lens 2, the third lens 3, the fifth lens 5, the sixth lens 6, and the seventh lens 7, both the object side and the image side are aspherical surfaces, and the surface profiles of each aspherical lens can be defined by, but are not limited to, the following aspherical formula:

[0034] Among them, x is the distance from the corresponding point on the aspherical surface to the plane tangent to the surface vertex, h is the distance from the corresponding point on the aspherical surface to the optical axis, c is the curvature of the aspherical vertex, k is the conic coefficient, and Ai is the coefficient corresponding to the i-th high-order term in the aspherical surface profile formula. Table 4 gives the conic coefficients and high-order term coefficients A4, A6, A8, A10, A12, A14, A16, A18, and A20 for each aspherical surface that can be used in Embodiment 2.

[0035] Table 4: Aspherical surface related values of the lens surfaces in Embodiment 2

[0036] Figure 5 The astigmatism and distortion curves of the optical imaging lens in Embodiment 2 are shown. Astigmatism represents the curvature of the meridional image plane and the sagittal image plane, and distortion represents the distortion magnitude values corresponding to different image heights; Figure 6The MTF curve of the optical imaging lens of Embodiment 2 is shown, which represents the MTF values in the meridional direction and sagittal direction of different fields of view at different spatial frequencies. It can be seen from Figure 5 and Figure 6 that the optical imaging system given in Embodiment 2 can achieve good imaging quality and has higher imaging quality.

[0037] Specifically, as a preferred implementation manner of the present invention rather than a limitation, as shown in Figures 7-9 , in this Embodiment 3, the focal length f1 of the first lens 1 is -8.83 mm, the focal length f2 of the second lens 2 is -4.93 mm, the focal length f3 of the third lens 3 is 10.68 mm, the focal length f4 of the fourth lens 4 is 6.21 mm, the focal length f5 of the fifth lens 5 is 12.17 mm, the focal length f6 of the sixth lens 6 is -4.04 mm, the focal length f7 of the seventh lens 7 is 4.43 mm, the total optical length TTL = 24 mm, and the surface type, radius of curvature, thickness and material parameters of each lens are shown in Table 5: Table 5: Basic parameters of the optical system of Embodiment 3

[0038] In the above Table 5, along the optical axis from the object surface to the image surface, OBJ is the object surface; S1 and S2 correspond to the two surfaces of the first lens 1; S3 and S4 correspond to the two surfaces of the second lens 2; S5 and S6 correspond to the two surfaces of the third lens 3; S8 and S9 correspond to the two surfaces of the fourth lens 4; S10 and S11 correspond to the two surfaces of the fifth lens 5; S12 and S13 correspond to the two surfaces of the sixth lens 6, S13 and S14 correspond to the two surfaces of the seventh lens 7; STO is the position of the aperture stop; S15 and S16 correspond to the two surfaces of the filter; S17 and S18 correspond to the two surfaces of the chip protection glass; IMA corresponds to the image surface.

[0039] Furthermore, in Table 5, any one of the object side and image side of the second lens 2, the third lens 3, the fifth lens 5, the sixth lens 6, and the seventh lens 7 is an aspherical surface. The surface shape of each aspherical lens can be defined by, but not limited to, the following aspherical formula:

[0040] where x is the distance from the corresponding point on the aspherical surface to the plane tangent to the surface vertex, h is the distance from the corresponding point on the aspherical surface to the optical axis, c is the curvature of the aspherical vertex, k is the conic coefficient, and Ai is the coefficient corresponding to the i-th high-order term in the aspherical surface formula. Table 6 gives the conic coefficients and high-order term coefficients A4, A6, A8, A10, A12, A14, A16, A18, and A20 that can be used for each aspherical surface in Embodiment 3.

[0041] Table 6: Aspherical related values of the lens surface in Example 3

[0042] Figure 8 The astigmatism and distortion curves of the optical imaging lens in Example 3 are shown. Astigmatism represents the curvature of the meridional image plane and the sagittal image plane, and distortion represents the distortion magnitude values corresponding to different image heights; Figure 9 The MTF curve of the optical imaging lens in Example 3 is shown, which represents the MTF values in the meridional direction and the sagittal direction of different fields of view at different spatial frequencies. It can be seen from Figure 8 and Figure 9 that the optical imaging system given in Example 3 can achieve good imaging quality and has higher imaging quality.

[0043] Furthermore, in Examples 1 - 3, the basic data are as follows: Table 7: Basic data of Examples 1 - 3

[0044] An imaging module includes at least an optical lens. The optical system sequentially consists of a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens along the optical axis from the object plane to the image plane. By reasonably distributing the surface shape and optical power of each lens, the lens aberration is optimized, enabling it to have excellent resolution, high pixels, a large aperture, athermalization, day-night confocal, light weight, etc., and having greater competitiveness in the IPC market.

[0045] As described above, one or more implementation manners are provided in combination with specific contents, and it is not determined that the specific implementation of the present invention is only limited to these descriptions. Any approximation or similarity to the method and structure of the present invention, or any several technical deductions or substitutions made under the premise of the inventive concept of the present invention, should be regarded as the protection scope of the present invention.

Claims

1. A day-night confocal optical system, which is composed of a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens in sequence from the object plane to the image plane along the optical axis, characterized in that: The object side of the first lens is convex, the image side is concave, and its optical power is negative; The object side of the second lens is convex, the image side is concave, and its optical power is negative; The object side of the third lens is concave, the image side is convex, and its optical power is positive; The object side and the image side of the fourth lens are both convex, and its optical power is positive; The object side and the image side of the fifth lens are both convex, and its optical power is positive; The object side and the image side of the sixth lens are both concave, and its optical power is negative; The object side and the image side of the seventh lens are both convex, and its optical power is positive; Each lens of the optical system meets the following conditions: -10.5mm<f1<-6.5mm; -6.1 mm<f2<-3.9 mm; 9.5mm<f3<15.5mm; 5.3mm<f4<7.5mm; 8.5mm<f5<13.5mm; -5.5mm<f6<-3.9mm; 3.5mm<f7<6.5mm; Among them, 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 and night confocal optical system according to claim 1, characterized in that: Each lens of the optical system meets the following conditions: Nd1>1.51,Vd1<65; Nd2>1.53,Vd2<56; Nd3>1.66,Vd3<25; Nd4>1.47,Vd4<85; Nd5>1.53,Vd5<56; Nd6>1.66,Vd6<25; Nd7>1.53,Vd7<56; Among them, 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.

3. The day and night confocal optical system according to claim 1, characterized in that: The relative illumination of the maximum field of view of the optical system meets the requirement of RI ≥ 35%.

4. The day and night confocal optical system according to any one of claims 1 to 3, characterized in that: The curvature radius R1 of the object surface side of the first lens satisfies: R1 > 25 mm.

5. The day and night confocal optical system according to any one of claims 1 to 3, characterized in that: The total optical length TTL of the system satisfies: TTL ≤ 25 mm.

6. The day and night confocal optical system according to any one of claims 1 to 3, characterized in that: The fourth lens is a glass lens.

7. The day and night confocal optical system according to any one of claims 1 to 3, characterized in that: The horizontal field angle FOV of the optical system satisfies: FOV ≥ 185°, and the maximum image circle satisfies: MIC ≥ 5.8 mm.

8. The day and night confocal optical system according to any one of claims 1 to 3, characterized in that: The aperture is arranged between the third lens and the fourth lens.

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

10. A camera module, comprising at least an optical lens, characterized in that: The optical system according to any one of claims 1 to 9 is installed in the optical lens.

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