A low-distortion high-pixel optical system and a camera lens using the same

Abstract

The present invention discloses a low-distortion, high-pixel optical system and a camera lens used therein. The system is mainly composed of eight lenses, with a reasonable number of lenses and a simple structure. By rationally distributing the optical power of the lenses, lens aberrations are optimized, and resolution performance is improved. The system has the advantages of wide angle, small distortion, and high resolution. In video conferencing equipment using video transmission technology, the system can reduce image noise, achieve good imaging quality, and facilitate post-processing with algorithms.

Description

Technical Field

[0001] The present application relates to a low-distortion, high-pixel optical system and a camera lens used therein, and in particular to a low-distortion, high-pixel optical system used in video conferencing equipment and a camera lens used therein. Background Art

[0002] With technological advancements and the needs of socioeconomic development, video transmission technology has developed rapidly, and video conferencing equipment using video transmission technology has emerged. Currently, existing video transmission lenses typically have only around two million pixels, resulting in high image noise and poor image quality, which is not conducive to post-processing algorithms. Summary of the Invention

[0003] In order 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, the present application provides a low-distortion, high-pixel optical system with the advantages of wide angle, small distortion and high resolution.

[0004] A low-distortion, high-pixel optical system, comprising, along the optical axis, from the object plane to the image plane, a first lens, a second lens, a third lens, a fourth lens, an aperture, a fifth lens, a sixth lens, a seventh lens, and an eighth lens;

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

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

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

[0008] The fourth lens has a concave object side and a convex image side, and has positive optical power;

[0009] The fifth lens has a convex object side and a convex image side, and its optical power is positive;

[0010] The object side of the sixth lens is concave, the image side is convex, and its optical power is positive;

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

[0012] The object side of the eighth lens is convex, the image side is convex, and its optical power is positive;

[0013] The first lens and the fourth lens are spherical lenses, and the second lens, the third lens, the sixth lens, the seventh lens, and the eighth lens are aspherical lenses.

[0014] As described above, the low-distortion, high-pixel optical system has lenses that meet the following conditions:

[0015] (1) -15mm<f1<-11mm;

[0016] (2) -7mm<f2<-4mm;

[0017] (3)7mm<f3<10mm;

[0018] (4) 18mm<f4<28mm;

[0019] (5) 5mm<f5<10mm;

[0020] (6) 3mm<f6<7mm;

[0021] (7) -6mm<f7<-3mm;

[0022] (8) 4mm<f8<9mm;

[0023] 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.

[0024] As described above, the low-distortion, high-pixel optical system has lenses that meet the following conditions:

[0025] (1) -7<f1 / f<-5;

[0026] (2) -4<f2 / f<-1;

[0027] (3)2<f3 / f<5;

[0028] (4)9<f4 / f<15;

[0029] (5)3.5<f5 / f<7;

[0030] (6)1.5<f6 / f<5;

[0031] (7) -3<f7 / f<-1;

[0032] (8)1.5<f8 / f<5;

[0033] Among them, f is the focal length of the entire optical system, 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.

[0034] In the low-distortion, high-pixel optical system described above, the material refractive index Nd1 and the material Abbe constant Vd1 of the first lens satisfy the following conditions: 1.8<Nd1<2.0, 30<Vd1<50; and / or

[0035] The material refractive index Nd2 and the material Abbe number Vd2 of the second lens satisfy the following conditions: 1.42<Nd2<1.75, 45<Vd2<70.

[0036] In the low-distortion, high-pixel optical system described above, the material refractive index Nd3 and the material Abbe number Vd3 of the third lens satisfy the following conditions: 1.42<Nd3<1.75, 15<Vd3<30; and / or

[0037] The material refractive index Nd4 and the material Abbe number Vd4 of the fourth lens satisfy: 1.65<Nd4<1.85, 40<Vd4<60.

[0038] In the low-distortion, high-pixel optical system described above, the material refractive index Nd5 and the material Abbe number Vd5 of the fifth lens satisfy the following conditions: 1.45<Nd5<1.72, 40<Vd5<60; and / or

[0039] The refractive index Nd6 and the Abbe number Vd6 of the material of the sixth lens satisfy: 1.45<Nd6<1.65, 45<Vd6<75.

[0040] In the low-distortion, high-pixel optical system described above, the refractive index Nd7 and the Abbe number Vd7 of the seventh lens element satisfy the following conditions: 1.65<Nd7<1.95, 17.5<Vd7<35; and / or

[0041] The material refractive index Nd8 and the material Abbe number Vd8 of the eighth lens satisfy: 1.45<Nd8<1.7, 45<Vd8<60.

[0042] The low-distortion, high-pixel optical system as described above satisfies the following relationship: 0.29<f / TTL*ImagH<0.35; wherein f is the effective focal length of the optical system, TTL is the on-axis distance from the object side of the first lens to the imaging surface, and ImgH is half the diagonal length of the effective pixel area on the imaging surface.

[0043] As described above, the low-distortion, high-pixel optical system has a full field of view (FOV) that satisfies the following conditions: 115° < FOV < 125°, and an F number of 2.0.

[0044] On the other hand, an embodiment of the present application further provides a video transmission camera lens.

[0045] A camera lens comprises a lens barrel, in which the above-mentioned low-distortion high-pixel optical system is installed.

[0046] Compared with the prior art, the present invention has the following advantages:

[0047] The present invention provides a low-distortion, high-pixel optical system, which is mainly composed of 8 lenses. The number of lenses is reasonable and the structure is simple. By rationally distributing the optical focal length of the lenses, lens aberrations are 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for describing the embodiments.

[0049] Figure 1 Schematic diagram of the structure of the optical system or camera lens in Example 1 of the present application;

[0050] Figure 2 is a distortion curve diagram of the optical system or camera lens in Example 1 of the present application;

[0051] Figure 3 is an MTF curve diagram of the optical system or camera lens of Example 1 of the present application;

[0052] Figure 4 2 is a schematic structural diagram of an optical system or camera lens according to embodiment 2 of the present application;

[0053] Figure 5 is a distortion curve diagram of the optical system or camera lens according to Example 2 of the present application;

[0054] Figure 6 is an MTF curve diagram of the optical system or camera lens of Example 2 of the present application;

[0055] Figure 7 Schematic diagram of the structure of the optical system or camera lens in Example 3 of the present application;

[0056] Figure 8 is a distortion curve diagram of the optical system or camera lens of Example 3 of the present application;

[0057] Figure 9 This is an MTF curve diagram of the optical system or camera lens in Example 3 of the present application. DETAILED DESCRIPTION

[0058] The present application provides a low-distortion, high-pixel optical system, including a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, an aperture STO, a fifth lens E5, a sixth lens E6, a seventh lens E7, an eighth lens E8, and a filter E9, which are arranged in sequence from the object side along the optical axis.

[0059] The object side of the first lens E1 is convex, the image side is concave, and its optical power is negative;

[0060] The object side of the second lens E2 is convex, the image side is concave, and its optical power is negative;

[0061] The object side and image side of the third lens E3 are convex, and its optical power is positive;

[0062] The fourth lens E4 has a concave object side and a convex image side, and has positive refractive power.

[0063] The fifth lens E5 has a convex object side surface and a convex image side surface, and has positive refractive power;

[0064] The sixth lens E6 has a concave object side and a convex image side, and has positive refractive power.

[0065] The seventh lens E7 has a concave object side and a convex image side, and has negative refractive power.

[0066] The eighth lens E8 has a convex object side surface and a convex image side surface, and has positive optical power;

[0067] The first lens E1 and the fourth lens E4 are spherical lenses, and the second lens E2, the third lens E3, the sixth lens E6, the seventh lens E7, and the eighth lens E8 are aspherical lenses.

[0068] The present invention provides a low-distortion, high-pixel optical system, which is mainly composed of 8 lenses. The number of lenses is reasonable and the structure is simple. By rationally distributing the optical focal length of the lenses, lens aberrations are 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.

[0069] Preferably, each lens of the optical system satisfies the following conditions:

[0070] (1) -15mm<f1<-11mm;

[0071] (2) -7mm<f2<-4mm;

[0072] (3)7mm<f3<10mm;

[0073] (4) 18mm<f4<28mm;

[0074] (5) 5mm<f5<10mm;

[0075] (6) 3mm<f6<7mm;

[0076] (7) -6mm<f7<-3mm;

[0077] (8) 4mm<f8<9mm;

[0078] Among them, f1 is the focal length of the first lens E1, f2 is the focal length of the second lens E2, f3 is the focal length of the third lens E3, f4 is the focal length of the fourth lens E4, f5 is the focal length of the fifth lens E5, f6 is the focal length of the sixth lens E6, f7 is the focal length of the seventh lens E7, and f8 is the focal length of the eighth lens E8. By reasonably allocating the focal lengths of each lens, the image has the characteristics of wide angle and small distortion, and at the same time has the advantages of high angular resolution, which can reduce image noise, achieve good imaging quality, and facilitate post-processing by algorithms.

[0079] Preferably, each lens of the optical system satisfies the following conditions:

[0080] (1) -7<f1 / f<-5, by constraining the effective focal length ratio of the first lens E1 and the optical system to a reasonable range, the distortion of the system is controlled, so that the imaging center has a higher angular resolution;

[0081] (2) -4<f2 / f<-1, by constraining the effective focal length ratio of the second lens E2 and the optical imaging system to 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;

[0082] (3) 2<f3 / f<5, by constraining the effective focal length ratio of the third lens E3 and the optical imaging system to a reasonable range, the spherical aberration of the system is fine-tuned and controlled, thereby effectively improving the imaging quality of the system;

[0083] (4) 9<f4 / f<15, by reasonably controlling the ratio range of the fourth lens E4 and the effective focal length of the optical imaging system, the astigmatism and field curvature of the system are well corrected, and the imaging quality of the system is effectively improved;

[0084] (5) 3.5<f5 / f<7, by constraining the ratio of the optical power of the fifth lens E5 to the effective focal length of the optical imaging system to 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;

[0085] (6) 1.5<f6 / f<5, by constraining the effective focal length ratio of the sixth lens E6 and the optical imaging system to a reasonable range, lens aberrations are optimized and analytical performance is improved;

[0086] (7) -3<f7 / f<-1, by constraining the effective focal length ratio of the seventh lens E7 and the optical imaging system to a reasonable range, it is possible to ensure good optical performance, optimize lens aberrations, improve resolution performance, and further ensure the viewing angle;

[0087] (8) 1.5<f8 / f<5. By constraining the effective focal length ratio of the eighth lens element E8 to the optical imaging system within a reasonable range, it is possible to achieve a balance in the internal aberrations of the optical lens, thereby helping to adjust the field curvature and astigmatism at the imaging edge of the optical lens, thereby meeting the imaging quality of the optical lens for the surrounding environment.

[0088] Wherein, f is the focal length of the entire optical system, f1 is the focal length of the first lens E1, f2 is the focal length of the second lens E2, f3 is the focal length of the third lens E3, f4 is the focal length of the fourth lens E4, f5 is the focal length of the fifth lens E5, f6 is the focal length of the sixth lens E6, f7 is the focal length of the seventh lens E7, and f8 is the focal length of the eighth lens E8.

[0089] Preferably, the refractive index Nd1 and the Abbe constant Vd1 of the material of the first lens E1 satisfy the following conditions: 1.8<Nd1<2.0, 30<Vd1<50. This design can effectively reduce chromatic aberration, optimize lens aberration, and thereby effectively improve the imaging quality of the system.

[0090] Preferably, the refractive index Nd2 and the Abbe number Vd2 of the material of the second lens element E2 satisfy the following conditions: 1.42<Nd2<1.75, 45<Vd2<70, which can ensure good optical performance, further ensure the viewing angle, improve the lens resolution and reduce distortion.

[0091] Preferably, the refractive index Nd3 and the Abbe number Vd3 of the material of the third lens E3 satisfy the following conditions: 1.42<Nd3<1.75, 15<Vd3<30. This design can effectively reduce chromatic aberration, optimize lens aberration, and thereby effectively improve the imaging quality of the system.

[0092] Preferably, the refractive index Nd4 and the Abbe number Vd4 of the material of the fourth lens element E4 satisfy the following conditions: 1.65<Nd4<1.85, 40<Vd4<60, which can ensure good optical performance, further ensure the viewing angle, improve the lens resolution and reduce distortion.

[0093] Preferably, the refractive index Nd5 and the Abbe number Vd5 of the material of the fifth lens element E5 satisfy the following conditions: 1.45<Nd5<1.72, 40<Vd5<60. This design can effectively reduce chromatic aberration, optimize lens aberration, and thereby effectively improve the imaging quality of the system.

[0094] Preferably, the refractive index Nd6 and the Abbe number Vd6 of the material of the sixth lens element E6 satisfy the following conditions: 1.45<Nd6<1.65, 45<Vd6<75. This design can effectively reduce chromatic aberration, optimize lens aberration, and thereby effectively improve the imaging quality of the system.

[0095] Preferably, the refractive index Nd7 and the Abbe number Vd7 of the material of the seventh lens element E7 satisfy the following conditions: 1.65<Nd7<1.95, 17.5<Vd7<35, which can ensure good optical performance, further ensure the viewing angle, improve the lens resolution and reduce distortion.

[0096] The refractive index Nd8 and Abbe number Vd8 of the eighth lens element E8 satisfy the following conditions: 1.45<Nd8<1.7, 45<Vd8<60, which can ensure good optical performance, further ensure the viewing angle, improve the lens's resolving power, and reduce distortion.

[0097] Preferably, the optical system satisfies the following relationship: 0.29 < f / TTL * ImagH < 0.35; where f is the effective focal length of the optical system, TTL is the on-axis distance from the object side of the first lens E1 to the imaging plane, and ImgH is half the diagonal length of the effective pixel area on the imaging plane. This relationship reflects the constraints on the field of view and thinness of the optical lens. When the above relationship is satisfied, the optical lens can meet the market demand for a small head and thinness while maintaining a wide angle. When the upper limit of the relationship is exceeded, while maintaining a wide angle of view, f / TTL * ImagH is further reduced, which will excessively compress the thinness of the optical lens and is not conducive to improving the performance of the optical lens. When it is below the lower limit of the relationship, the optical lens is not thin enough, which is not conducive to miniaturization of the optical lens design.

[0098] Preferably, the full field of view FOV of the optical system satisfies: 115°<FOV<125°, and the F number of the optical system is 2.0. This design can effectively miniaturize the lens. The optical system configured in the present invention has the advantages of wide angle, compact structure, easy processing and installation, increased light input to the optical system and higher imaging quality. Through reasonable distribution of optical focal length and optimized selection of high-order aspheric parameters, it can achieve small distortion while taking into account high resolution and wide-angle shooting functions.

[0099] Specifically, as a preferred embodiment of the present invention but not limiting, refer to Figures 1 to 3 Describe the optical imaging lens according to Example 1 of the present application, Figure 1 FIG. 1 shows a schematic structural diagram of an optical imaging lens according to Example 1 of the present application. Figure 1As shown, the first lens E1 has negative focal power, with its object-side surface S1 being convex and its image-side surface S2 being concave. The second lens E2 has negative focal power, with its object-side surface S3 being convex and its image-side surface S4 being concave. The third lens E3 has positive focal power, with its object-side surface S5 being convex and its image-side surface S6 being convex. The fourth lens E4 has positive focal power, with its object-side surface S7 being concave and its image-side surface S8 being convex. The fifth lens E5 has positive focal power, with its object-side surface S9 being convex and its image-side surface S10 being convex. The sixth lens E6 has positive focal power, with its object-side surface S11 being concave and its image-side surface S12 being convex. The seventh lens E7 has negative focal power, with its object-side surface S13 being concave and its image-side surface S14 being convex. The eighth lens E8 has positive focal power, with its object-side surface S15 being convex and its image-side surface S16 being convex. The filter E9 has an object-side surface S17 and an image-side surface S18. Light from the object passes through the surfaces S1 to S18 in sequence and is finally imaged on the imaging surface S19.

[0100] Table 1 shows the surface type, curvature radius, thickness, and material of each lens of the optical imaging lens of Example 1, where the units of curvature radius and thickness are both millimeters (mm):

[0101] Table 1: Basic parameters of the optical system of Example 1

[0102]

[0103]

[0104] In Table 1 above, any one of the object side and image side of the second lens E2, the third lens E3, and the fifth lens E5 to the eighth lens E8 is aspherical. The surface shape of each aspherical lens can be defined by, but not limited to, the following aspherical formula:

[0105]

[0106] Where 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 aspheric vertex, k is the conic coefficient, and Ai is the coefficient corresponding to the i-th higher-order term in the aspheric surface shape formula. Table 2 shows the conic coefficients and higher-order coefficients A4, A6, A8, A10, A12, A14, and A16 for various aspheric surfaces that can be used in Example 1.

[0107] Table 2: Aspheric surface related values ​​of the lens surface of Example 1

[0108] Surface number K A4 A6 A8 A10 A12 A14 A16 3 7.418E-01 -1.8005E-04 -4.1272E-05 2.9575E-07 -5.3341E-09 7.5818E-11 0.0000E+00 0.0000E+00 4 -8.454E-01 -4.3480E-04 2.1814E-04 -1.3154E-06 1.7433E-07 2.6598E-09 -1.4981E-08 0.0000E+00 5 -3.961E+01 -1.2657E-03 1.3713E-04 -1.4014E-05 -1.5982E-06 -2.4382E-09 1.5339E-08 -3.9189E-10 6 -3.091E+00 -4.9284E-04 1.7669E-04 -3.1804E-05 6.1696E-06 -8.3425E-07 1.5146E-07 -7.6585E-10 10 8.523E-01 -8.0950E-04 9.7413E-05 1.6471E-04 -5.2293E-06 0.0000E+00 0.0000E+00 0.0000E+00 11 -2.343E+01 -5.6232E-05 7.2695E-04 6.8712E-05 2.7994E-05 0.0000E+00 0.0000E+00 0.0000E+00 12 -4.258E+00 2.7670E-03 1.6320E-04 -1.3770E-04 -5.0733E-05 5.8590E-06 0.0000E+00 0.0000E+00 13 4.062E-02 7.4583E-03 -2.0268E-04 9.0039E-05 9.7984E-06 1.3771E-06 0.0000E+00 0.0000E+00 14 1.110E-02 9.3068E-03 -3.8188E-05 5.3939E-05 4.5078E-05 -7.2458E-07 0.0000E+00 0.0000E+00 15 0.000E+00 8.9371E-03 2.5085E-04 -2.1972E-05 -3.6206E-06 2.9003E-08 0.0000E+00 0.0000E+00 16 2.071E+01 3.7474E-04 2.0574E-04 1.3523E-05 -1.9001E-06 3.7202E-10 1.9704E-09 0.0000E+00 17 -3.054E+00 -4.9906E-04 -2.3091E-05 1.2464E-05 2.0388E-08 1.0883E-07 4.0071E-09 0.0000E+00

[0109] Figure 2The astigmatism and distortion curves of the optical imaging lens of Example 1 are shown. Astigmatism represents meridional image curvature and sagittal image curvature; distortion represents the distortion magnitude corresponding to different image heights.

[0110] 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.

[0111] Depend on Figure 2 and Figure 3 It can be seen that the optical lens provided in Example 1 can achieve good imaging quality.

[0112] Specifically, as a preferred embodiment of the present invention but not limiting, Figure 4 FIG. 1 shows a schematic structural diagram of an optical imaging lens according to Example 2 of the present application. Figure 4 As shown, the first lens E1 has negative focal power, with its object-side surface S1 being convex and its image-side surface S2 being concave. The second lens E2 has negative focal power, with its object-side surface S3 being convex and its image-side surface S4 being concave. The third lens E3 has positive focal power, with its object-side surface S5 being convex and its image-side surface S6 being convex. The fourth lens E4 has positive focal power, with its object-side surface S7 being concave and its image-side surface S8 being convex. The fifth lens E5 has positive focal power, with its object-side surface S9 being convex and its image-side surface S10 being convex. The sixth lens E6 has positive focal power, with its object-side surface S11 being concave and its image-side surface S12 being convex. The seventh lens E7 has negative focal power, with its object-side surface S13 being concave and its image-side surface S14 being convex. The eighth lens E8 has positive focal power, with its object-side surface S15 being convex and its image-side surface S16 being convex. The filter E9 has an object-side surface S17 and an image-side surface S18. Light from the object passes through the surfaces S1 to S18 in sequence and is finally imaged on the imaging surface S19.

[0113] Table 3 shows the surface type, curvature radius, thickness, and material of each lens of the optical imaging lens system of Example 2, where the units of curvature radius and thickness are both in millimeters (mm):

[0114] Table 3: Basic parameters of the optical system of Example 2

[0115]

[0116]

[0117] In Table 3 above, any one of the object side and image side of the second lens E2, the third lens E3, and the sixth lens E6 to the eighth lens E8 is aspherical. The surface shape of each aspherical lens can be defined by, but not limited to, the following aspherical surface formula:

[0118]

[0119] Where 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 aspheric vertex, k is the conic coefficient, and Ai is the coefficient corresponding to the i-th higher-order term in the aspheric surface shape formula. Table 4 shows the conic coefficients and higher-order coefficients A4, A6, A8, A10, A12, A14, and A16 for various aspheric surfaces that can be used in Example 2.

[0120] Table 4: Aspheric surface related values ​​of the lens surface of Example 2

[0121] Surface number K A4 A6 A8 A10 A12 A14 A16 3 7.978E-01 -5.3461E-05 -3.7220E-05 2.6768E-07 -1.8981E-08 7.5818E-11 0.0000E+00 0.0000E+00 4 -8.170E-01 1.4414E-04 1.0816E-04 2.5803E-06 9.3924E-07 -2.0979E-08 -2.5321E-08 0.0000E+00 5 -2.530E+01 -1.5450E-03 1.1203E-04 -1.3581E-05 -1.9098E-06 2.2037E-08 1.6388E-08 -3.9189E-10 6 -4.488E+00 -3.5955E-04 7.2435E-05 -2.6491E-05 4.4726E-06 1.3877E-07 6.4009E-09 -7.6585E-10 11 5.501E+00 2.0477E-03 -4.1983E-04 -5.0062E-05 -6.3606E-05 -5.9539E-06 0.0000E+00 0.0000E+00 12 4.507E-02 7.1608E-03 -3.8156E-04 8.5520E-06 4.2666E-06 4.4720E-09 0.0000E+00 0.0000E+00 13 9.061E-02 9.2638E-03 -1.7460E-04 -4.4462E-05 2.4397E-05 4.4070E-06 0.0000E+00 0.0000E+00 14 0.000E+00 8.5639E-03 1.6137E-04 -2.5639E-05 -2.0330E-06 2.0447E-07 0.0000E+00 0.0000E+00 15 1.990E+01 2.9781E-04 2.1138E-04 1.1212E-05 -1.5011E-06 3.7202E-10 1.9704E-09 0.0000E+00 16 -2.836E+00 -3.5702E-04 5.1390E-06 1.1750E-05 -2.3956E-07 1.1803E-07 4.0071E-09 0.0000E+00

[0122] Figure 5 The astigmatism and distortion curves of the optical imaging lens of Example 2 are shown. Astigmatism represents meridional image curvature and sagittal image curvature; distortion represents the distortion magnitude corresponding to different image heights.

[0123] 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.

[0124] Depend on Figure 5 and Figure 6 It can be seen that the optical imaging lens provided in Example 2 can achieve good imaging quality.

[0125] Specifically, as a preferred embodiment of the present invention but not limiting, Figure 7 FIG. 4 shows a schematic structural diagram of an optical imaging lens according to Example 3 of the present application. Figure 7 As shown, the first lens E1 has negative focal power, with its object-side surface S1 being convex and its image-side surface S2 being concave. The second lens E2 has negative focal power, with its object-side surface S3 being convex and its image-side surface S4 being concave. The third lens E3 has positive focal power, with its object-side surface S5 being convex and its image-side surface S6 being convex. The fourth lens E4 has positive focal power, with its object-side surface S7 being concave and its image-side surface S8 being convex. The fifth lens E5 has positive focal power, with its object-side surface S9 being convex and its image-side surface S10 being convex. The sixth lens E6 has positive focal power, with its object-side surface S11 being concave and its image-side surface S12 being convex. The seventh lens E7 has negative focal power, with its object-side surface S13 being concave and its image-side surface S14 being convex. The eighth lens E8 has positive focal power, with its object-side surface S15 being convex and its image-side surface S16 being convex. The filter E9 has an object-side surface S17 and an image-side surface S18. Light from the object passes through the surfaces S1 to S18 in sequence and is finally imaged on the imaging surface S19.

[0126] Table 5 shows the surface type, curvature radius, thickness, and material of each lens of the optical imaging lens system of Example 3, where the units of curvature radius and thickness are both millimeters (mm).

[0127] Table 5: Basic parameters of the optical system of Example 3

[0128] Face number Surface type Curvature radius (mm) Thickness (mm) Material OBJ spherical surface endless 800 S1 spherical surface 9.420 0.850 1.91,35.26 S2 spherical surface 4.982 0.902 S3 Aspheric 6.133 0.920 1.54,55.71 S4 Aspheric 1.900 3.143 S5 Aspheric 26.115 2.450 1.64,23.55 S6 Aspheric -6.651 0.615 S7 spherical surface -5.401 2.820 1.77,49.61 S8 spherical surface -5.270 0.100 STO spherical surface endless 0.250 S9 spherical surface 6.019 1.460 1.57,56.06 S10 spherical surface -23.537 0.325 S11 Aspheric -8.306 1.510 1.54,55.71 S12 Aspheric -2.324 0.050 S13 Aspheric -2.519 0.760 1.66,20.37 S14 Aspheric -41.321 0.290 S15 Aspheric 13.093 2.760 1.54,55.71 S16 Aspheric -4.532 0.800 S17 spherical surface endless 0.800 1.52,64.17 S18 spherical surface endless 1.524 S19 spherical surface endless

[0129] In Table 5 above, any one of the object side and image side of the second lens E2, the third lens E3, and the sixth lens E6 to the eighth lens E8 is aspherical. The surface shape of each aspherical lens can be defined by, but not limited to, the following aspherical surface formula:

[0130]

[0131] Where 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 aspheric vertex, k is the conic coefficient, and Ai is the coefficient corresponding to the i-th higher-order term in the aspheric surface shape formula. Table 6 shows the conic coefficients and higher-order coefficients A4, A6, A8, A10, A12, A14, and A16 for various aspheric surfaces that can be used in the first embodiment.

[0132] Table 6: Aspheric surface related values ​​of the lens surface of Example 3

[0133] Surface number K A4 A6 A8 A10 A12 A14 A16 3 6.590E-01 1.4776E-04 -5.2844E-05 -1.2819E-07 -8.8111E-09 7.5818E-11 0.0000E+00 0.0000E+00 4 -7.864E-01 -4.2748E-05 1.4420E-04 -1.4124E-05 -1.9997E-07 2.2551E-09 -2.9342E-08 0.0000E+00 5 -1.357E+02 -3.3480E-03 9.7655E-06 -8.3784E-06 -4.3469E-06 -4.7939E-07 8.7123E-08 -3.9189E-10 6 1.475E-01 -2.0699E-03 2.5661E-04 -6.6035E-05 5.2826E-06 1.0440E-07 1.5838E-10 -7.6585E-10 11 5.349E+00 1.9784E-03 -8.7226E-04 -1.1423E-04 -5.5506E-05 -1.5750E-06 0.0000E+00 0.0000E+00 12 -2.865E-01 7.6919E-03 -5.1821E-04 8.3746E-05 -3.7266E-05 6.0917E-06 0.0000E+00 0.0000E+00 13 2.090E-02 1.1264E-02 1.0206E-03 -1.6045E-04 2.7159E-05 7.9527E-06 0.0000E+00 0.0000E+00 14 0.000E+00 9.9018E-03 3.5767E-04 -5.8104E-05 -2.7630E-06 2.0510E-07 0.0000E+00 0.0000E+00 15 1.202E+01 1.5068E-03 1.2406E-05 -1.3436E-06 -6.1768E-07 3.7202E-10 1.9704E-09 0.0000E+00 16 -3.687E+00 -1.3472E-03 -1.5986E-04 1.9744E-05 -1.7066E-06 7.8326E-08 4.0071E-09 0.0000E+00

[0134] Figure 8 The astigmatism and distortion curves of the optical imaging lens of Example 3 are shown. Astigmatism represents meridional image curvature and sagittal image curvature; distortion represents the distortion magnitude corresponding to different image heights.

[0135] 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.

[0136] Depend on Figure 8 and Figure 9 It can be seen that the optical imaging lens provided in Example 3 can achieve good imaging quality.

[0137] A video transmission camera lens comprises at least a lens barrel, in which the above-mentioned low-distortion high-pixel optical system is installed.

[0138] 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 rationally allocating the optical focal length of the lenses, lens aberrations are 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 beneficial to later algorithm processing.

[0139] The above descriptions are provided in conjunction with specific content to provide one or more embodiments, and the specific implementation of the present invention is not limited to these descriptions. Any similarity or similarity with the methods, structures, etc. of the present invention, or any technical deduction or substitution based on the concept of the present invention, shall be considered within the scope of protection of the present invention.

Claims

1. A low-distortion, high-pixel optical system, comprising, along the optical axis, from the object plane to the image plane, a first lens, a second lens, a third lens, a fourth lens, an aperture, 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, 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 convex, and its optical power is positive; The fourth lens has a concave object side and a convex image side, and has positive optical power; The fifth lens has a convex object side and a convex image side, and its optical power is positive; The object side of the sixth lens is concave, the image side is 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 of the eighth lens is convex, the image side is convex, and its optical power is positive; The first lens and the fourth lens are spherical lenses, and the second lens, the third lens, the sixth lens, the seventh lens, and the eighth lens are aspherical lenses; Each lens of the optical system meets the following conditions: (1) -15mm<f1<-11mm; (2) -7mm<f2<-4mm; (3) 7mm<f3<10mm; (4) 18mm<f4<28mm; (5) 5mm<f5<10mm; (6) 3mm<f6<7mm; (7) -6mm<f7<-3mm; (8) 4mm<f8<9mm; 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, high-pixel optical system according to claim 1, wherein: Each lens of the optical system meets the following conditions: (1) -7<f1 / f<-5; (2) -4<f2 / f<-1; (3) 2<f3 / f<5; (4) 9<f4 / f<15; (5) 3.5<f5 / f<7; (6) 1.5<f6 / f<5; (7) -3<f7 / f<-1; (8) 1.5<f8 / f<5; Among them, f is the focal length of the entire optical system, 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, high-pixel optical system according to any one of claims 1-2, wherein: The material refractive index Nd1 and the material Abbe constant Vd1 of the first lens satisfy the following conditions: 1.8<Nd1<2.0, 30<Vd1<50; and / or The material refractive index Nd2 and the material Abbe number Vd2 of the second lens satisfy the following conditions: 1.42<Nd2<1.75, 45<Vd2<70.

4. The low-distortion, high-pixel optical system according to any one of claims 1-2, wherein: The refractive index Nd3 and the Abbe number Vd3 of the material of the third lens satisfy the following conditions: 1.42<Nd3<1.75, 15<Vd3<30; and / or The material refractive index Nd4 and the material Abbe number Vd4 of the fourth lens satisfy: 1.65<Nd4<1.85, 40<Vd4<60.

5. The low-distortion, high-pixel optical system according to any one of claims 1-2, wherein: The refractive index Nd5 and the Abbe number Vd5 of the material of the fifth lens satisfy the following conditions: 1.45<Nd5<1.72, 40<Vd5<60; and / or The refractive index Nd6 and the Abbe number Vd6 of the material of the sixth lens satisfy: 1.45<Nd6<1.65, 45<Vd6<75.

6. The low-distortion, high-pixel optical system according to any one of claims 1-2, wherein: The refractive index Nd7 and the Abbe number Vd7 of the material of the seventh lens satisfy the following conditions: 1.65<Nd7<1.95, 17.5<Vd7<35; and / or The material refractive index Nd8 and the material Abbe number Vd8 of the eighth lens satisfy: 1.45<Nd8<1.7, 45<Vd8<60.

7. The low-distortion, high-pixel optical system according to any one of claims 1-2, wherein: The optical system satisfies the following relationship: 0.29mm<f / TTL*ImgH<0.35mm; Where f is the effective focal length of the optical system, TTL is the on-axis distance from the object side of the first lens to the imaging surface, and ImgH is half the diagonal length of the effective pixel area on the imaging surface.

8. The low-distortion, high-pixel optical system according to any one of claims 1-2, wherein: The full field of view (FOV) of the optical system satisfies the following conditions: 115° < FOV < 125°, and the F number of the optical system is 2.

0.

9. A camera lens, comprising a lens barrel, wherein the low-distortion, high-pixel optical system according to any one of claims 1 to 8 is installed in the lens barrel.

Images