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

Abstract

The utility model provides a low distortion optical system and an applied camera module, mainly comprising 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] This application relates to the field of optical systems, and in particular to a low-distortion, high-pixel optical system for use in video conferencing equipment and a camera module for the application thereof. Background Technology

[0002] With technological advancements and the needs of socio-economic development, video transmission technology has developed rapidly, leading to the emergence of video conferencing equipment utilizing this technology. Currently, existing video transmission lenses typically have only around two million pixels, resulting in high image noise, poor image quality, and difficulties in post-processing algorithms. Utility Model Content

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

[0004] A low-distortion, high-pixel optical system comprises, along the optical axis from the object plane to the image plane, 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.

[0005] The object side of the first lens is convex, and the image side is concave; its optical power is negative.

[0006] The object side of the second lens is convex, and the image side is concave; its optical power is negative.

[0007] The object side of the third lens is convex, and the image side is concave; its optical power is negative.

[0008] The fourth lens has a convex surface on the object side and a concave surface on the image side, and its optical power is negative.

[0009] The fifth lens has convex surfaces on both the object plane and image plane sides, and its optical power is positive.

[0010] The object plane and image plane of the sixth lens are both convex, and its optical power is positive.

[0011] The object side of the seventh lens is concave, and the image side is convex; its optical power is negative.

[0012] The object plane and image plane of the eighth lens are both convex, and its optical power is positive.

[0013] Preferably, each lens of the optical system satisfies the following conditions:

[0014] -35mm < f1 < -25mm;

[0015] -8.9mm < f2 < -5.8mm;

[0016] -16mm < f3 < -11mm;

[0017] 15.7mm < f4 < 39.5mm;

[0018] 7.3mm < f5 < 8.5mm;

[0019] 3.9mm < f6 < 5.3mm;

[0020] -5.5mm < f7 < -4.5mm;

[0021] 6.3mm < f8 < 8.6mm;

[0022] 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, f7 is the focal length of the seventh lens, and f8 is the focal length of the eighth lens.

[0023] Preferably, each lens of the optical system satisfies the following conditions:

[0024] Nd1 > 1.5, Vd1 < 60.2;

[0025] Nd2 < 1.6, Vd2 > 53.2;

[0026] Nd3 < 1.6, Vd3 > 60;

[0027] Nd4 > 1.70, Vd4 < 50;

[0028] Nd5 < 1.85, Vd5 > 45;

[0029] Nd6 < 1.65, Vd6 > 60;

[0030] Nd7 < 1.9, Vd7 > 22;

[0031] Nd8 > 1.53, Vd8 < 57;

[0032] Wherein, 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.

[0033] Preferably, the maximum angle CRA of the principal ray incident on the image plane across the entire field of view of the optical system satisfies: CRA < 17°.

[0034] Preferably, the radii of curvature R of the object plane and image plane sides of the second lens both satisfy: R > 0;

[0035] Preferably, the total optical length (TTL) of the optical system satisfies: TTL ≤ 31 mm.

[0036] Preferably, the second lens is a plastic lens and the third lens is a glass lens.

[0037] Preferably, the F-number of this optical system is: 1.9 ≤ F-number ≤ 2.3

[0038] Preferably, the aperture is positioned between the fifth lens and the sixth lens, and the sixth lens and the seventh lens are bonded together to form a combined lens.

[0039] On the other hand, embodiments of this application also provide a camera module, which includes at least an optical lens, and the aforementioned low-distortion optical system is installed in the optical lens.

[0040] Compared with the prior art, the beneficial effects of this application are as follows:

[0041] This invention provides a low-distortion optical system and its application in a camera module, mainly composed of eight lenses. The first lens has a convex object side and a concave image side, with negative optical power; the second lens has a convex object side and a concave image side, with negative optical power; the third lens has a convex object side and a concave image side, with negative optical power; the fourth lens has a convex object side and a concave image side, with negative optical power; and the fifth lens has convex object and image sides. The optical power of the sixth lens is positive; both the object and image sides of the sixth lens are convex, so its optical power is positive; the object side of the seventh lens is concave, and the image side is convex, so its optical power is negative; both the object and image sides of the eighth lens are convex, so its optical power is positive. The number of lenses is reasonable, the structure is simple, and by rationally distributing the optical power of the lenses, the lens aberrations are optimized, the imaging quality of the optical system is improved, and the characteristics of ultra-wide-angle, high-definition resolution and excellent temperature characteristics are taken into account, which has great potential in the market. Attached Figure Description

[0042] 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.

[0043] Figure 1 This is a schematic diagram of the structure of the optical system or camera module in Embodiment 1 of this application;

[0044] Figure 2This is a graph showing the astigmatism and distortion of the optical system or camera module in Embodiment 1 of this application;

[0045] Figure 3 This is the MTF curve of the optical system or camera module of Embodiment 1 of this application;

[0046] Figure 4 This is a schematic diagram of the structure of the optical system or camera module in Embodiment 2 of this application;

[0047] Figure 5 This is a graph showing the astigmatism and distortion of the optical system or camera module in Embodiment 2 of this application;

[0048] Figure 6 This is the MTF curve of the optical system or camera module in Embodiment 2 of this application;

[0049] Figure 7 This is a schematic diagram of the structure of the optical system or camera module in Embodiment 3 of this application;

[0050] Figure 8 This is a graph showing the astigmatism and distortion of the optical system or camera module in Embodiment 3 of this application;

[0051] Figure 9 This is the MTF curve of the optical system or camera module in Embodiment 3 of this application. Detailed Implementation

[0052] like Figure 1-9 As shown, this 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.

[0053] The object plane side of the first lens is convex, and the image plane side is concave, and its optical power is negative.

[0054] The object side of the second lens is convex, and the image side is concave; its optical power is negative.

[0055] The object side of the third lens is convex, and the image side is concave; its optical power is negative.

[0056] The fourth lens has a convex surface on the object side and a concave surface on the image side, and its optical power is negative.

[0057] The fifth lens has convex surfaces on both the object plane and image plane sides, and its optical power is positive.

[0058] The object plane and image plane of the sixth lens are both convex, and its optical power is positive.

[0059] The object side of the seventh lens is concave, and the image side is convex; its optical power is negative.

[0060] The object plane and image plane of the eighth lens are both convex, and its optical power is positive.

[0061] This invention provides a low-distortion optical system and its application in a camera module, mainly composed of eight lenses. The first lens has a convex object side and a concave image side, with negative optical power; the second lens has a convex object side and a concave image side, with negative optical power; the third lens has a convex object side and a concave image side, with negative optical power; the fourth lens has a convex object side and a concave image side, with negative optical power; and the fifth lens has convex object and image sides. The optical power of the sixth lens is positive; both the object and image sides of the sixth lens are convex, so its optical power is positive; the object side of the seventh lens is concave, and the image side is convex, so its optical power is negative; both the object and image sides of the eighth lens are convex, so its optical power is positive. The number of lenses is reasonable, the structure is simple, and by rationally distributing the optical power of the lenses, the lens aberrations are optimized, the imaging quality of the optical system is improved, and the characteristics of ultra-wide-angle, high-definition resolution and excellent temperature characteristics are taken into account, which has great potential in the market.

[0062] Furthermore, as a preferred embodiment of this utility model and not a limitation thereof, 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:

[0063] (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, so that the imaging center has a higher angular resolution;

[0064] (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 stability of the optical system in imaging at high and low temperatures and improving the imaging quality;

[0065] (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 finely adjusted and controlled, thereby effectively improving the imaging quality of the system;

[0066] (4) 15.7mm < f4 < 39.5mm. By reasonably 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, and the imaging quality of the system is effectively improved.

[0067] (5) 7.3mm < f5 < 8.5mm. 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 stability of the optical system in imaging at high and low temperatures and improving the imaging quality.

[0068] (6) 3.9mm < f6 < 5.3mm, by constraining the effective focal length of the sixth lens E6 within a reasonable range, the lens aberration is optimized and the resolution performance is improved;

[0069] (7) -5.5mm < f7 < -4.5mm. By constraining the effective focal length of the seventh lens E7 within a reasonable range, good optical performance can be guaranteed, lens aberrations can be optimized, resolution performance can be improved, and the viewing angle can be further guaranteed.

[0070] (8) 6.3mm < f8 < 8.6mm. By constraining the effective focal length of the eighth lens E8 within a reasonable range, the internal aberrations of the optical lens can be balanced, which in turn helps to adjust the field curvature and astigmatism at the imaging edge of the optical lens and meet the imaging quality of the optical lens for the surrounding environment.

[0071] Preferably, the refractive index Nd1 and Abbe constant Vd1 of the material 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.

[0072] Preferably, the refractive index Nd2 and Abbe number Vd2 of the material of the second lens E2 satisfy: Nd2 < 1.6, Vd2 > 53.2, which can ensure good optical performance, further guarantee the viewing angle, improve the lens resolution and reduce distortion;

[0073] Preferably, the refractive index Nd3 and Abbe number Vd3 of the material 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.

[0074] Preferably, the refractive index Nd4 and Abbe number Vd4 of the fourth lens E4 satisfy: Nd4 > 1.70, Vd4 < 50, which can ensure good optical performance, further guarantee the viewing angle, improve the lens resolution and reduce distortion.

[0075] Preferably, the refractive index Nd5 and 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.

[0076] Preferably, the refractive index Nd6 and Abbe number Vd6 of the material 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.

[0077] Preferably, the refractive index Nd7 and Abbe number Vd7 of the seventh lens E7 satisfy: Nd7 < 1.9, Vd7 > 22, which can ensure good optical performance, further guarantee the viewing angle, improve the lens resolution and reduce distortion.

[0078] Preferably, the refractive index Nd8 and Abbe number Vd8 of the material of the eighth lens E8 satisfy: Nd8 > 1.53, Vd8 < 57, which can ensure good optical performance, further guarantee the viewing angle, improve the lens resolution and reduce distortion;

[0079] Furthermore, as a preferred embodiment of the present invention and not a limitation thereof, the maximum angle CRA of the main ray incident on the image plane of the full field of view of the optical system satisfies: CRA < 17°. This design can make the CRA of the lens and the CRA of the chip more compatible, thereby improving the light sensitivity of the chip.

[0080] Furthermore, as a preferred embodiment of this utility model and not a limitation, the curvature radius R of both the object plane and the image plane of the second lens satisfies: R > 0. By controlling the R values ​​of the object and image planes of the second lens, distortion can be effectively calibrated and the imaging quality of the system can be improved.

[0081] Furthermore, as a preferred embodiment of the present invention and not a limitation thereof, the total optical length (TTL) of the optical system satisfies: TTL ≤ 31 mm. This design allows for sufficient space between the lenses to improve the performance of the system.

[0082] Furthermore, as a preferred embodiment of the present invention and not a limitation thereof, the second lens is a plastic lens and the third lens is a glass lens. This design can improve performance at high and low temperatures.

[0083] Furthermore, as a preferred embodiment of this utility model and not a limitation thereof, the F-number and FOV of the optical system satisfy: 1.9 ≤ F-number ≤ 2.3. The large aperture configuration can increase the amount of light entering the optical system and achieve higher imaging quality.

[0084] Furthermore, as a preferred embodiment of this utility model and not a limitation thereof, the sixth lens and the seventh lens are bonded together to form a combined lens. The refractive index Nd6 and Abbe number Vd6 of the sixth lens, and the refractive index Nd7 and 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, which can effectively reduce chromatic aberration.

[0085] Specifically, as a preferred embodiment of this utility model and not a limitation thereof, such as Figure 1-3 As shown, in this embodiment 1, the focal length of the first lens 1 is f1 = -28.24 mm, the focal length of the second lens 2 is f2 = -7.32 mm, the focal length of the third lens 3 is f3 = -15.92 mm, the focal length of the fourth lens 4 is f4 = 34.95 mm, the focal length of the fifth lens 5 is f5 = 8.27 mm, the focal length of the sixth lens 6 is f6 = 4.63 mm, the focal length of the seventh lens 7 is f7 = -5.09 mm, the focal length of the eighth lens 8 is f8 = 7.65 mm, the total optical length TTL is 30 mm, and the surface type, radius of curvature, thickness, and material parameters of each lens are shown in Table 1.

[0086] Table 1: Basic parameters of the optical system in Example 1

[0087]

[0088] 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 location of the aperture stop; S17 and S18 correspond to the two surfaces of the filter; IMA corresponds to the image plane.

[0089] Furthermore, in Table 1, the object-side surface and image-side surface of either the second lens 2 or the eighth lens 8 are aspherical. The surface shape of each aspherical lens can be defined using, but is not limited to, the following aspherical formula:

[0090]

[0091] 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, and Ai is the coefficient corresponding to the i-th higher-order term in the aspherical surface shape formula. Table 2 gives the conic coefficients and higher-order term coefficients A4, A6, A8, A10, A12, A14, A16, A18, and A20 that can be used for each aspherical surface in Example 1.

[0092] Table 2: Aspherical correlation values ​​of the lens surface in Example 1

[0093]

[0094] Figure 2 The astigmatism and distortion curves of the optical imaging lens 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 distortion magnitude value 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 meridional and sagittal directions of different fields of view at different spatial frequencies. Figure 2 and Figure 3 It can be seen that the optical imaging system given in Example 1 can achieve good imaging quality and has higher imaging quality.

[0095] Specifically, as a preferred embodiment of this utility model and not a limitation thereof, such as Figure 4-6 As shown, in this embodiment 2, the focal length of the first lens 1 is f1 = -29.40 mm, the focal length of the second lens 2 is f2 = -7.47 mm, the focal length of the third lens 3 is f3 = -12.44 mm, the focal length of the fourth lens 4 is f4 = 24.05 mm, the focal length of the fifth lens 5 is f5 = 8.26 mm, the focal length of the sixth lens 6 is f6 = 4.64 mm, the focal length of the seventh lens 7 is f7 = -5.03 mm, the focal length of the eighth lens 8 is f8 = 7.7 mm, the total optical length TTL = 30 mm, and the surface type, radius of curvature, thickness, and material parameters of each lens are shown in Table 3.

[0096] Table 3: Basic parameters of the optical system in Example 2

[0097]

[0098] In Table 3 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 location of the aperture stop; S17 and S18 correspond to the two surfaces of the filter; IMA corresponds to the image plane.

[0099] Furthermore, in Table 3, the object-side surface and image-side surface of either the second lens 2 or the eighth lens 8 are aspherical. The surface shape of each aspherical lens can be defined using, but is not limited to, the following aspherical formula:

[0100]

[0101] 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, and Ai is the coefficient corresponding to the i-th higher-order term in the aspherical surface shape formula. Table 4 gives the conic coefficients and higher-order term coefficients A4, A6, A8, A10, A12, A14, A16, A18, and A20 that can be used for each aspherical surface in Example 2.

[0102] Table 4: Aspherical correlation values ​​of the lens surface in Example 2

[0103]

[0104] Figure 5 The astigmatism and distortion curves of the optical imaging lens in 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 MTF curve of the optical imaging lens of Example 2 is shown, which represents the MTF values ​​in the meridional and sagittal directions of different fields of view at different spatial frequencies. Figure 5 and Figure 6 It can be seen that the optical imaging system given in Example 2 can achieve good imaging quality and has higher imaging quality.

[0105] Specifically, as a preferred embodiment of this utility model and not a limitation thereof, such as Figure 7-9As shown, in this embodiment 3, the focal length of the first lens 1 is f1 = -27.30 mm, the focal length of the second lens 2 is f2 = -7.65 mm, the focal length of the third lens 3 is f3 = -12.27 mm, the focal length of the fourth lens 4 is f4 = 22.78 mm, the focal length of the fifth lens 5 is f5 = 8.26 mm, the focal length of the sixth lens 6 is f6 = 4.62 mm, the focal length of the seventh lens 7 is f7 = -4.85 mm, the focal length of the eighth lens 8 is f8 = 8 mm, and the total optical length TTL is 30.1 mm. The surface type, radius of curvature, thickness, and material parameters of each lens are shown in Table 5.

[0106] Table 5: Basic parameters of the optical system in Example 3

[0107]

[0108] 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 location of the aperture stop; S17 and S18 correspond to the two surfaces of the filter; IMA corresponds to the image plane.

[0109] Furthermore, in Table 5, the object-side surface and image-side surface of either the second lens 2 or the eighth lens 8 are aspherical. The surface shape of each aspherical lens can be defined using, but is not limited to, the following aspherical formula:

[0110]

[0111] 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, and Ai is the coefficient corresponding to the i-th higher-order term in the aspherical surface shape formula. Table 6 gives the conic coefficients and higher-order term coefficients A4, A6, A8, A10, A12, A14, A16, A18, and A20 of each aspherical surface that can be used in Example 3.

[0112] Table 6: Aspherical Correlation Values ​​of Lens Surface in Example 3

[0113]

[0114] Figure 8The 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 curvature of the sagittal image plane, and distortion represents the magnitude of distortion at different image heights. Figure 9 The MTF curve of the optical imaging lens of Example 3 is shown, which represents the MTF values ​​in the meridional and sagittal directions of different fields of view at different spatial frequencies. Figure 8 and Figure 9 It can be seen that the optical imaging system given in Example 3 can achieve good imaging quality and has higher imaging quality.

[0115] Furthermore, in Examples 1-3, the basic data is as follows:

[0116] Table 7: Basic Data for Examples 1-3

[0117]

[0118] A camera module includes at least an optical lens, within which the aforementioned low-distortion optical system is installed. The camera lens of this embodiment is mainly composed of eight lenses, with a reasonable number of lenses and a simple structure. By rationally allocating the optical power of the lenses, lens aberrations are optimized, and resolution performance is improved. It has the advantages of wide-angle, low distortion, and high resolution. In video conferencing equipment using video transmission technology, it can reduce image noise, achieve good imaging quality, and facilitate post-processing algorithms.

[0119] The above description provides one or more embodiments in conjunction with specific content, and does not imply that the specific implementation of this utility model is limited to these descriptions. Any methods or structures that are similar to or identical to those of this utility model, or any technical deductions or substitutions made based on the concept of this utility model, should be considered within the protection scope of this utility model.

Claims

1. A low-distortion optical system, comprising, sequentially from the object plane to the image plane along the optical axis, 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, characterized in that: The object side of the first lens is convex, and the image side is concave; its optical power is negative. The object side of the second lens is convex, and the image side is concave; its optical power is negative. The object side of the third lens is convex, and the image side is concave; its optical power is negative. The fourth lens has a convex surface on the object side and a concave surface on the image side, and its optical power is negative. The fifth lens has convex surfaces on both the object plane and image plane sides, and its optical power is positive. The object plane and image plane of the sixth lens are both convex, and its optical power is positive. The object side of the seventh lens is concave, and the image side is convex; its optical power is negative. The object plane and image plane of the eighth lens are both convex, and its optical power is positive.

2. The low-distortion optical system according to claim 1, characterized in that: Each lens in this optical system satisfies the following condition: -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; 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, f7 is the focal length of the seventh lens, and f8 is the focal length of the eighth lens.

3. The low-distortion optical system according to claim 1, characterized in that: Each lens in this optical system satisfies the following condition: 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; Wherein, 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.

4. The low-distortion optical system according to any one of claims 1-3, characterized in that: The maximum angle CRA of the principal ray incident on the image plane in the full field of view of this optical system satisfies: CRA < 17°.

5. The low-distortion optical system according to any one of claims 1-3, characterized in that: The radii of curvature R of the object plane and image plane sides of the second lens both satisfy: R > 0.

6. The low-distortion optical system according to any one of claims 1-3, characterized in that: The total optical length (TTL) of the optical system satisfies: TTL ≤ 31 mm.

7. The low-distortion optical system according to any one of claims 1-3, characterized in that: The second lens is a plastic lens, and the third lens is a glass lens.

8. The low-distortion optical system according to any one of claims 1-3, characterized in that: The F-number of this optical system is: 1.9 ≤ F-number ≤ 2.

3.

9. The low-distortion optical system according to any one of claims 1-3, characterized in that: The aperture stop is positioned between the fifth and sixth lenses; The sixth and seventh lenses 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 according to any one of claims 1-9.

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