Low-distortion optical system and camera module applied by low-distortion optical system

Abstract

The invention provides a low-distortion optical system and a camera module applying the low-distortion optical system, the low-distortion optical system is mainly composed of eight lenses, the object plane side of the first lens is a convex surface, the image plane side of the first lens is a concave surface, and the focal power of the first lens 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 convex surface, the image plane side is a concave surface, and the focal power is negative; the object plane side of the fourth lens is a convex surface, the image plane side is a concave surface, and the focal power is negative; 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 convex surfaces, and the focal power of the sixth lens is positive; the object plane side of the seventh lens is a concave surface, the image plane side is a convex surface, and the focal power is negative; the object plane side and the image plane side of the eighth lens are convex surfaces, the focal power is positive, the imaging quality of the optical system is improved by reasonably distributing the focal power of the lenses and optimizing the aberration of the lens, and the characteristics of ultra-wide angle, high-definition resolution and excellent temperature characteristic are considered.

Description

Technical Field

[0001] The present application relates to the field of optical systems, and in particular to a low-distortion, high-pixel optical system used in video conferencing equipment and a camera module using the same. Background Art

[0002] With the advancement of technology and the needs of social and economic development, video transmission technology has developed rapidly, and video conferencing equipment using video transmission technology has emerged. Currently, the existing video transmission lenses usually have only about 2 million pixels, high image noise, poor image quality, and are not conducive to post-processing algorithms. Summary of the invention

[0003] The present application aims to overcome the common problems of high image noise and poor imaging quality in existing optical systems or camera lenses used for video transmission lenses. On the one hand, the present application provides a low-distortion and high-pixel optical system with the advantages of wide angle, small distortion and high resolution.

[0004] A low-distortion high-pixel optical system, which is composed of a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens in sequence from the object plane to the image plane along the optical axis; 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 convex, the image side is concave, and its optical power is negative; The object side of the fourth lens is convex, the image side is concave, and its optical power is negative; 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 convex, and its optical power is positive; The object side of the seventh lens is concave, the image side is convex, and its optical power is negative; The object side and the image side of the eighth lens are both convex surfaces, and its optical power is positive.

[0005] Preferably, each lens of the optical system satisfies the following conditions: -35mm<f1<-25mm; -8.9mm<f2<-5.8mm; -16mm<f3<-11mm; 15.7mm<f4<39.5mm; 7.3mm<f5<8.5mm; 3.9mm<f6<5.3mm; -5.5mm<f7<-4.5mm; 6.3mm<f8<8.6mm; 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, f7 is the focal length of the seventh lens, and f8 is the focal length of the eighth lens.

[0006] Preferably, each lens of the optical system satisfies the following conditions: Nd1>1.5,Vd1<60.2; Nd2<1.6,Vd2>53.2; Nd3<1.6,Vd3>60; Nd4>1.70,Vd4<50; Nd5<1.85,Vd5>45; Nd6<1.65,Vd6>60; Nd7<1.9,Vd7>22; Nd8>1.53,Vd8<57; 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; Nd8 is the refractive index of the eighth lens, and Vd8 is the Abbe number of the eighth lens.

[0007] Preferably, the maximum angle CRA of the full-field chief ray of the optical system incident on the image plane satisfies: CRA <17°.

[0008] Preferably, the curvature radii R of the object surface and the image surface side of the second lens both satisfy: R > 0; Preferably, the total optical length TTL of the optical system satisfies: TTL ≤ 31 mm.

[0009] Preferably, the second lens is a plastic lens, and the third lens is a glass lens.

[0010] Preferably, the F number of the optical system is: 1.9≤F number≤2.3 Preferably, the aperture stop is disposed between the fifth lens and the sixth lens, and the sixth lens and the seventh lens are bonded to each other to form a combined lens.

[0011] On the other hand, an embodiment of the present application further provides a camera module, comprising at least an optical lens, wherein the optical lens is installed with the above-mentioned low-distortion optical system.

[0012] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a low-distortion optical system and a camera module used therein, which is mainly composed of 8 lenses. The object side of the first lens is convex, the image side is concave, and the optical power is negative; the object side of the second lens is convex, the image side is concave, and the optical power is negative; the object side of the third lens is convex, the image side is concave, and the optical power is negative; the object side of the fourth lens is convex, the image side is concave, and the optical power is negative; the object side and the image side of the fifth lens are both convex, and the optical power is negative. The focal power is positive; the object side and image side of the sixth lens are both convex, and its optical focal power is positive; the object side of the seventh lens is concave, the image side is convex, and its optical focal power is negative; the object side and image side of the eighth lens are both convex, and its optical focal power is positive. The number of lenses is reasonable and the structure is simple. By reasonably allocating the optical power of the lenses, optimizing the lens aberrations, and improving the imaging quality of the optical system, taking into account the characteristics of ultra-wide angle, high-definition resolution, and excellent temperature characteristics, it has huge potential in the market. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for describing the embodiments are briefly introduced below.

[0014] Figure 1 It is a structural schematic diagram of the optical system or camera module of Example 1 of the present application; Figure 2 is an astigmatism and distortion curve diagram of the optical system or camera module of Example 1 of the present application; Figure 3 is an MTF curve diagram of the optical system or camera module of Example 1 of the present application; Figure 4 It is a structural schematic diagram of an optical system or a camera module according to Embodiment 2 of the present application; Figure 5 is an astigmatism and distortion curve diagram of the optical system or camera module of Example 2 of the present application; Figure 6 is an MTF curve diagram of the optical system or camera module of Example 2 of the present application; Figure 7 It is a structural schematic diagram of an optical system or a camera module according to Embodiment 3 of the present application; Figure 8 is an astigmatism and distortion curve diagram of the optical system or camera module of Example 3 of the present application; Fig. 9 It is an MTF curve diagram of the optical system or camera module of Example 3 of the present application. DETAILED DESCRIPTION

[0015] like Figure 1-9 As shown, the present application provides a low distortion optical system, which is composed of a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a fifth lens 5, an aperture 9, a sixth lens 6, a seventh lens 7, an eighth lens 8, and an infrared filter 10 in sequence along the optical axis from the object plane to the image plane.

[0016] 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 convex, the image side is concave, and its optical power is negative; The object side of the fourth lens is convex, the image side is concave, and its optical power is negative; 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 convex, and its optical power is positive; The object side of the seventh lens is concave, the image side is convex, and its optical power is negative; The object side and the image side of the eighth lens are both convex, and its optical power is positive; The present invention provides a low-distortion optical system and a camera module used therein, which is mainly composed of 8 lenses. The object side of the first lens is convex, the image side is concave, and the optical power is negative; the object side of the second lens is convex, the image side is concave, and the optical power is negative; the object side of the third lens is convex, the image side is concave, and the optical power is negative; the object side of the fourth lens is convex, the image side is concave, and the optical power is negative; the object side and the image side of the fifth lens are both convex, and the optical power is negative. The focal power is positive; the object side and image side of the sixth lens are both convex, and its optical focal power is positive; the object side of the seventh lens is concave, the image side is convex, and its optical focal power is negative; the object side and image side of the eighth lens are both convex, and its optical focal power is positive. The number of lenses is reasonable and the structure is simple. By reasonably allocating the optical power of the lenses, optimizing the lens aberrations, and improving the imaging quality of the optical system, taking into account the characteristics of ultra-wide angle, high-definition resolution, and excellent temperature characteristics, it has huge potential in the market.

[0017] Further, as a preferred embodiment of the present invention but not limiting, each lens of the optical system satisfies the following conditions, 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, f7 is the focal length of the seventh lens, and f8 is the focal length of the eighth lens: (1) -35mm<f1<-25mm, by constraining the effective focal length of the first lens E1 within a reasonable range, the distortion of the system is controlled, and the imaging center has a higher angular resolution; (2) -8.9mm<f2<-5.8mm. By constraining the effective focal length of the second lens E2 within a reasonable range, the configured optical system has excellent temperature characteristics, thereby improving the imaging stability of the optical system at high and low temperatures and improving the imaging quality. (3) -16mm<f3<-11mm, by constraining the effective focal length of the third lens E3 within a reasonable range, the spherical aberration of the system is fine-tuned and controlled, thereby effectively improving the imaging quality of the system; (4) 15.7mm<f4<39.5mm. By properly controlling the effective focal length of the fourth lens E4 within a reasonable range, the astigmatism and field curvature of the system are well corrected, effectively improving the imaging quality of the system. (5) 7.3 mm < f5 < 8.5 mm. By constraining the effective focal length of the fifth lens E5 within a reasonable range, the configured optical system has excellent temperature characteristics, thereby improving the imaging stability of the optical system at high and low temperatures and improving the imaging quality. (6) 3.9 mm < f6 < 5.3 mm, by constraining the effective focal length of the sixth lens E6 within a reasonable range, lens aberrations are optimized and analytical performance is improved; (7) -5.5mm<f7<-4.5mm. By constraining the effective focal length of the seventh lens element E7 within a reasonable range, good optical performance can be ensured, lens aberrations can be optimized, resolution performance can be improved, and the viewing angle can be further guaranteed. (8) 6.3 mm < f8 < 8.6 mm. By constraining the effective focal length of the eighth lens element E8 within a reasonable range, the internal aberrations of the optical lens can be balanced, thereby helping to adjust the field curvature and astigmatism at the imaging edge of the optical lens, thereby satisfying the imaging quality of the optical lens for the surrounding environment.

[0018] Preferably, the material refractive index Nd1 and the material Abbe constant Vd1 of the first lens E1 satisfy: Nd1>1.5, Vd1<60.2. This design can effectively reduce chromatic aberration, optimize lens aberration, and thus effectively improve the imaging quality of the system. Preferably, the material refractive index Nd2 and the material Abbe number Vd2 of the second lens E2 satisfy: Nd2<1.6, Vd2>53.2, which can ensure good optical performance, further ensure the viewing angle, improve the lens resolution and reduce distortion; Preferably, the material refractive index Nd3 and the material Abbe number Vd3 of the third lens E3 satisfy: Nd3<1.6, Vd3>60. This design can effectively reduce chromatic aberration, optimize lens aberration, and thus effectively improve the imaging quality of the system. Preferably, the material refractive index Nd4 and the material Abbe number Vd4 of the fourth lens E4 satisfy: Nd4>1.70, Vd4<50, which can ensure good optical performance, further ensure the viewing angle, improve the lens resolution and reduce distortion; Preferably, the material refractive index Nd5 and the material Abbe number Vd5 of the fifth lens E5 satisfy: Nd5<1.85, Vd5>45. This design can effectively reduce chromatic aberration, optimize lens aberration, and thus effectively improve the imaging quality of the system. Preferably, the material refractive index Nd6 and the material Abbe number Vd6 of the sixth lens E6 satisfy: Nd6<1.65, Vd6>60. This design can effectively reduce chromatic aberration, optimize lens aberration, and thus effectively improve the imaging quality of the system. Preferably, the material refractive index Nd7 and the material Abbe number Vd7 of the seventh lens E7 satisfy: Nd7<1.9, Vd7>22, which can ensure good optical performance, further ensure the viewing angle, improve the lens resolution and reduce distortion; Preferably, the material refractive index Nd8 and the material Abbe number Vd8 of the eighth lens E8 satisfy: Nd8>1.53, Vd8<57, which can ensure good optical performance, further ensure the viewing angle, improve the lens resolution and reduce the distortion. Further, as a preferred embodiment of the present invention but not a limitation, the maximum angle CRA of the full-field chief light of the optical system incident on the image plane satisfies: CRA < 17°. This design can make the CRA of the lens more consistent with the CRA of the chip, thereby improving the photosensitivity efficiency of the chip.

[0019] Furthermore, as a preferred embodiment of the present invention but not limitation, the curvature radii R of the object and image sides of the second lens both satisfy: R > 0. By controlling the R values ​​of the object and image sides of the second lens, the distortion can be effectively calibrated to improve the imaging quality of the system.

[0020] Further, as a preferred embodiment of the present invention but not limitation, the total optical length TTL of the optical system satisfies: TTL ≤ 31 mm. This design can provide sufficient space between the lenses to improve the performance of the system.

[0021] Further, as a preferred embodiment of the present invention but not limiting, the second lens is a plastic lens and the third lens is a glass lens. This design can improve the performance under high and low temperature conditions; Further, as a preferred embodiment of the present invention but not limiting, the F number and FOV of the optical system satisfy: 1.9≤F number≤2.3, and the configuration of a large aperture can increase the amount of light entering the optical system and achieve higher imaging quality; Further, as a preferred embodiment of the present invention but not limiting, the sixth lens and the seventh lens are bonded together to form a combined lens, and the refractive index Nd6 and the Abbe number Vd6 of the sixth lens, as well as the refractive index Nd7 and the Abbe number Vd7 of the seventh lens, satisfy: Nd6<1.65, Vd6>60; Nd7<1.9, Vd7>22. This design increases the difference between the refractive index and the Abbe number of the lens, and can effectively reduce chromatic aberration.

[0022] Specifically, as a preferred embodiment of the present invention but not limiting, Figure 1-3 As shown, in this embodiment 1, the focal length f1 of the first lens 1 is -28.24mm, the focal length f2 of the second lens 2 is -7.32mm, the focal length f3 of the third lens 3 is -15.92mm, the focal length f4 of the fourth lens 4 is 34.95mm, the focal length f5 of the fifth lens 5 is 8.27mm, the focal length f6 of the sixth lens 6 is 4.63mm, the focal length f7 of the seventh lens 7 is -5.09mm, the focal length f8 of the eighth lens 8 is 7.65mm, the total optical length TTL is 30mm, and 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 of Example 1

[0023] 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; S7 and S8 correspond to the two surfaces of the fourth lens 4; S9 and S10 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; S15 and S16 correspond to the two surfaces of the eighth lens 8; STO is the position of the aperture; S17 and S18 correspond to the two surfaces of the filter; IMA corresponds to the image plane.

[0024] Further, in Table 1, the object side surface and the image side surface of any one of the second lens 2 and the eighth lens 8 are aspherical surfaces, and the surface shape of each aspherical lens can be defined by but not limited to the following aspherical surface formula:

[0025] Wherein, 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 cone coefficient, and Ai is the coefficient corresponding to the i-th high-order term in the aspherical surface shape formula. Table 2 shows the cone coefficients and high-order term coefficients A4, A6, A8, A10, A12, A14, A16, A18 and A20 of each aspherical surface that can be used in Example 1.

[0026] Table 2: Aspheric surface related values ​​of the lens surface of Example 1

[0027] Figure 2 The astigmatism and distortion curves of the optical imaging lens of Example 1 are shown, where astigmatism represents the meridional image curvature and the sagittal image curvature, and distortion represents the distortion magnitude values ​​corresponding to different image heights; Figure 3 The MTF curve of the optical imaging lens of Example 1 is shown, which represents the MTF values ​​in the meridian direction and sagittal direction of different fields of view at different spatial frequencies. Figure 2 and Figure 3 It can be seen that the optical imaging system provided in Example 1 can achieve good imaging quality and has higher imaging quality.

[0028] Specifically, as a preferred embodiment of the present invention but not limiting, Figure 4-6 As shown, in this embodiment 2, the focal length f1 of the first lens 1 is -29.40 mm, the focal length f2 of the second lens 2 is -7.47 mm, the focal length f3 of the third lens 3 is -12.44 mm, the focal length f4 of the fourth lens 4 is 24.05 mm, the focal length f5 of the fifth lens 5 is 8.26 mm, the focal length f6 of the sixth lens 6 is 4.64 mm, the focal length f7 of the seventh lens 7 is -5.03 mm, the focal length f8 of the eighth lens 8 is 7.7 mm, the total optical length TTL is 30 mm, and the surface type, curvature radius, thickness and material parameters of each lens are shown in Table 3: Table 3: Basic parameters of the optical system of Example 2

[0029] 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; S7 and S8 correspond to the two surfaces of the fourth lens 4; S9 and S10 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; S15 and S16 correspond to the two surfaces of the eighth lens 8; STO is the position of the aperture; S17 and S18 correspond to the two surfaces of the filter; IMA corresponds to the image plane.

[0030] Further, in Table 3, the object side surface and the image side surface of any one of the second lens 2 and the eighth lens 8 are aspherical surfaces, and the surface shape of each aspherical lens can be defined by but not limited to the following aspherical surface formula:

[0031] Wherein, 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 cone coefficient, and Ai is the coefficient corresponding to the i-th high-order term in the aspherical surface shape formula. Table 4 shows the cone coefficients and high-order term coefficients A4, A6, A8, A10, A12, A14, A16, A18 and A20 of each aspherical surface that can be used in Example 2.

[0032] Table 4: Aspheric surface related values ​​of lens surface in Example 2

[0033] Figure 5 The astigmatism and distortion curves of the optical imaging lens of Example 2 are shown, where astigmatism represents the meridional image curvature and the sagittal image curvature, and distortion represents the distortion magnitude values ​​corresponding to different image heights; Figure 6 The MTF curve of the optical imaging lens of Example 2 is shown, which represents the MTF values ​​in the meridian direction and sagittal direction of different fields of view at different spatial frequencies. Figure 5 and Figure 6 It can be seen that the optical imaging system provided in Example 2 can achieve good imaging quality and has higher imaging quality.

[0034] Specifically, as a preferred embodiment of the present invention but not limiting, Figure 7-9As shown, in this embodiment 3, the focal length f1 of the first lens 1 is -27.30 mm, the focal length f2 of the second lens 2 is -7.65 mm, the focal length f3 of the third lens 3 is -12.27 mm, the focal length f4 of the fourth lens 4 is 22.78 mm, the focal length f5 of the fifth lens 5 is 8.26 mm, the focal length f6 of the sixth lens 6 is 4.62 mm, the focal length f7 of the seventh lens 7 is -4.85 mm, the focal length f8 of the eighth lens 8 is 8 mm, the total optical length TTL is 30.1 mm, and the surface type, curvature radius, thickness and material parameters of each lens are shown in Table 5: Table 5: Basic parameters of the optical system of Example 3

[0035] In Table 5 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; S7 and S8 correspond to the two surfaces of the fourth lens 4; S9 and S10 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; S15 and S16 correspond to the two surfaces of the eighth lens 8; STO is the position of the aperture; S17 and S18 correspond to the two surfaces of the filter; IMA corresponds to the image plane.

[0036] Further, in Table 5, the object side surface and the image side surface of any one of the second lens 2 and the eighth lens 8 are aspherical surfaces, and the surface shape of each aspherical lens can be defined by but not limited to the following aspherical surface formula:

[0037] Wherein, x is the distance from the corresponding point on the aspheric surface to the plane tangent to the vertex of the surface, h is the distance from the corresponding point on the aspheric surface to the optical axis, c is the curvature of the vertex of the aspheric surface, k is the cone coefficient, and Ai is the coefficient corresponding to the i-th high-order term in the aspheric surface shape formula. Table 6 shows the cone coefficients and high-order term coefficients A4, A6, A8, A10, A12, A14, A16, A18 and A20 of each aspheric surface that can be used in Example 3.

[0038] Table 6: Aspheric surface related values ​​of lens surface in Example 3

[0039] Figure 8 The astigmatism and distortion curves of the optical imaging lens of Example 3 are shown, where astigmatism represents the meridional image curvature and the sagittal image curvature, and distortion represents the distortion magnitude values ​​corresponding to different image heights; Fig. 9The MTF curve of the optical imaging lens of Example 3 is shown, which represents the MTF values ​​in the meridian direction and sagittal direction of different fields of view at different spatial frequencies. Figure 8 and Fig. 9 It can be seen that the optical imaging system provided in Example 3 can achieve good imaging quality and has higher imaging quality.

[0040] Further, in Examples 1-3, the basic data are as follows: Table 7: Basic data of Examples 1-3

[0041] A camera module at least includes an optical lens, in which the above-mentioned low-distortion optical system is installed. The camera lens of the embodiment of the present invention is mainly composed of 8 lenses, with a reasonable number of lenses and a simple structure. By reasonably allocating the optical focal length of the lenses, the lens aberration is optimized, and the resolution performance is improved. It has the advantages of wide angle, small distortion and high resolution. In video conferencing equipment using video transmission technology, it can reduce image noise and achieve good imaging quality, which is conducive to later algorithm processing.

[0042] As described above, one or more implementation methods are provided in combination with specific contents, and the specific implementation of the present invention is not limited to these descriptions. Any similarity or similarity with the method, structure, etc. of the present invention, or any technical deduction or replacement based on the concept of the present invention, shall be regarded as the protection scope of the present invention.

Claims

1. A low distortion optical system, which is composed of a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth 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 convex, the image side is concave, and its optical power is negative; The object side of the fourth lens is convex, the image side is concave, and its optical power is negative; 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 convex, and its optical power is positive; The object side of the seventh lens is concave, the image side is convex, and its optical power is negative; The object side and the image side of the eighth lens are both convex, and its optical power is positive; Each lens of the optical system meets the following conditions: -35mm<f1<-25mm; -8.9mm<f2<-5.8mm; -16mm<f3<-11mm; 15.7mm<f4<39.5mm; 7.3mm<f5<8.5mm; 3.9mm<f6<5.3mm; -5.5mm<f7<-4.5mm; 6.3mm<f8<8.6mm; 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, f7 is the focal length of the seventh lens, and f8 is the focal length of the eighth lens.

2. The low distortion optical system according to claim 1, characterized in that: Each lens of the optical system meets the following conditions: Nd1>1.5,Vd1<60.2; Nd2<1.6,Vd2>53.2; Nd3<1.6,Vd3>60; Nd4>1.70,Vd4<50; Nd5<1.85,Vd5>45; Nd6<1.65,Vd6>60; Nd7<1.9,Vd7>22; Nd8>1.53,Vd8<57; 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; Nd8 is the refractive index of the eighth lens, and Vd8 is the Abbe number of the eighth lens.

3. The low distortion optical system according to claim 1, wherein: The maximum angle CRA of the full-field chief ray incident on the image plane of the optical system satisfies: CRA < 17°.

4. The low distortion optical system according to claim 1, wherein: The curvature radii R of the object surface and the image surface side of the second lens both satisfy: R > 0.

5. The low distortion optical system according to claim 1, wherein: The total optical length TTL of the optical system satisfies: TTL ≤ 31 mm.

6. The low distortion optical system according to claim 1, wherein: The second lens is a plastic lens, and the third lens is a glass lens.

7. The low distortion optical system according to claim 1, wherein: The F number of the optical system is: 1.9≤F number≤2.

3.

8. The low distortion optical system according to claim 1, wherein: The aperture is arranged between the fifth lens and the sixth lens.

9. The low distortion optical system according to claim 1, wherein: The sixth lens and the seventh lens are bonded together to form a combined lens.

10. A camera module, comprising at least an optical lens, characterized in that: The optical lens is equipped with the low-distortion optical system described in any one of claims 1 to 9.

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