Large-aperture miniaturized wide-angle lens

Abstract

The invention relates to a large-aperture miniaturized wide-angle lens, which comprises a first lens group with negative diopter, a second lens group with positive diopter and a third lens group with positive diopter in sequence from an object side to an image side, wherein the first lens group comprises a first sub-lens group with negative diopter and a second sub-lens group with positive diopter; an aperture is arranged between the second lens group and the third lens group, the second lens group comprises a focusing lens, and the focusing lens is used for long and short distance focusing; the first lens group further comprises at least one aspheric lens, so that the lens has the advantages of aspheric large aperture, fixed focal length and wide angle, is an imaging lens with large aperture, long flange distance, single focusing and excellent optical performance, and can realize wide angle, large aperture and rapid focusing on a long flange distance film camera.

Description

Technical Field

[0001] The invention belongs to the technical field of photographic lenses, and in particular relates to a large aperture miniaturized wide-angle lens. Background Art

[0002] In recent years, the demand for video shooting has increased year by year, and interchangeable lens micro-single cameras and digital video cameras have been widely used. However, the applicant found that most lenses on the market are full-frame wide-angle lenses with F / 2 or greater full-open F numbers, and most of them are micro-single camera lenses with short flange distances. Such short flange distance lenses cannot be transferred to long flange distance movie cameras for use. Summary of the invention

[0003] In order to solve the above problems existing in the prior art, the present invention provides a large aperture miniaturized wide-angle lens.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions: The present invention provides a large aperture miniaturized wide-angle lens, which comprises, from the object side to the image side, a first lens group with negative refractive power, a second lens group with positive refractive power, and a third lens group with positive refractive power; wherein, The first lens group comprises a first sub-lens group with negative refractive power and a second sub-lens group with positive refractive power; An aperture is provided between the second lens group and the third lens group, and the second lens group includes a focusing lens, which is used for focusing at long and short distances; The first lens group further includes at least one aspherical lens, the focal length of the aspherical lens is EFL_ASP, and satisfies the following conditional formula: -6≤EFL_ASP / EFL≤-2; 1.5≤EFL_ASP / EFL_G11≤4.5; Wherein, EFL is the focal length of the entire optical system at infinity; EFL_G11 is the focal length of the first sub-lens group in the first lens group.

[0005] Furthermore, the position of the aperture satisfies the following conditional formula: 1.6≤L / S_IL≤1.9; Where S_IL is the distance from the aperture to the imaging plane; L is the distance from the object side of the first rod lens of the first lens group to the imaging plane, starting from the object side.

[0006] Furthermore, the focal lengths of the first lens group, the second lens group and the third lens group satisfy the following conditional formula: 1≤|EFL_G3 / EFL_G1|≤1.8; 0.8≤|EFL_G3 / EFL_G2|≤1.4; Among them, EFL_G1 is the focal length of the first lens group; EFL_G2 is the focal length of the second lens group; EFL_G3 is the focal length of the third lens group.

[0007] Furthermore, the focal length of the focusing lens in the second lens group satisfies the following conditional formula: -8.5≤EFL_LF / EFL≤-3.8; Wherein, EFL_LF is the focal length of the focusing lens in the second lens group, and EFL is the focal length of the entire optical system at infinity.

[0008] Furthermore, the focal lengths of the first sub-lens group and the second sub-lens group in the first lens group satisfy the following conditional formula: -12≤EFL_G12 / EFL_G11≤-6; Wherein, EFL_G11 is the focal length of the first sub-lens group; EFL_G12 is the focal length of the second sub-lens group.

[0009] Furthermore, the third lens group includes at least one aspherical lens.

[0010] Further, the first lens group is composed of lenses L11 to L16 arranged in sequence from the object side to the image side, wherein the lenses L11 and L12 constitute a first sub-lens group, the lenses L13 to L16 constitute a second sub-lens group, the second lens group is composed of a focus lens LF, a lens L22, and a lens L23 arranged in sequence from the object side to the image side, and the third lens group is composed of lenses L31 to L37 arranged in sequence from the object side to the image side; Moreover, the focal length of the aspheric lens in the first lens group is EFL_ASP, which has a ratio of -3.25 to the focal length EFL of the entire optical system at infinity, and a ratio of 2.38 to the focal length EFL_G11 of the first sub-lens group; the ratio of the distance from the object side of the lens L11 to the image side of the lens L23 to the distance from the aperture to the image side of the lens L37 is 1.78; the ratios of the focal lengths of the third lens group to the first lens group and the second lens group are 1.28 and 1.18 respectively; the ratio of the focal length of the focusing lens LF in the second lens group to the focal length of the entire optical system at infinity is -7.72; and the ratio of the focal lengths of the second sub-lens group to the first sub-lens group is -8.94.

[0011] Alternatively, the first lens group is composed of lenses L11 to L17 arranged in sequence from the object side to the image side, wherein the lenses L11 to L3 constitute a first sub-lens group, the lenses L14 to L17 constitute a second sub-lens group, the second lens group is composed of lenses L21, focusing lens LF, and lens L23 arranged in sequence from the object side to the image side, and the third lens group is composed of lenses L31 to L38 arranged in sequence from the object side to the image side; Moreover, the focal length of the aspheric lens in the first lens group is EFL_ASP, which has a ratio of -5.08 to the focal length EFL of the entire optical system at infinity, and a ratio of 4.08 to the focal length EFL_G11 of the first sub-lens group; the ratio of the distance from the object side of the lens L11 to the image side of the lens L23 to the distance from the aperture to the image side of the lens L38 is 1.73; the ratios of the focal lengths of the third lens group to the first lens group and the second lens group are 1.69 and 1.26 respectively; the ratio of the focal length of the focusing lens LF in the second lens group to the focal length of the entire optical system at infinity is -6.6; and the ratio of the focal lengths of the second sub-lens group to the first sub-lens group is -11.78.

[0012] Alternatively, the first lens group is composed of lenses L11 to L16 arranged in sequence from the object side to the image side, wherein the lenses L11 to L13 constitute a first sub-lens group, the lenses L14 to L16 constitute a second sub-lens group, the second lens group is composed of a focus lens LF, a lens L22, and a lens L23 arranged in sequence from the object side to the image side, and the third lens group is composed of lenses L31 to L38 arranged in sequence from the object side to the image side; Moreover, the focal length of the aspheric lens in the first lens group is EFL_ASP, which has a ratio of -4.42 to the focal length EFL of the entire optical system at infinity, and a ratio of 3.49 to the focal length EFL_G11 of the first sub-lens group; the ratio of the distance from the object side of the lens L11 to the image side of the lens L23 to the distance from the aperture to the image side of the lens L38 is 1.71; the focal length ratios of the third lens group to the first lens group and the second lens group are 1.39 and 1 respectively; the focal length of the focusing lens LF in the second lens group has a ratio of -4.4 to the focal length of the entire optical system at infinity; the ratio of the focal length of the second sub-lens group to the first sub-lens group is -7.62.

[0013] Beneficial effects of the present invention: Through the above technical scheme, the lens of the present invention has the advantages of large aperture, fixed focal length and wide angle of aspheric surface. It is an imaging lens with large aperture, long flange distance, single-chip focusing and excellent optical performance, and can achieve wide angle, large aperture and fast focusing on a movie camera with long flange distance. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is an optical structure diagram of a large aperture miniaturized wide-angle lens according to Embodiment 1 of the present invention; Figure 2 is a diagram of spherical aberration, field curvature aberration, and distortion aberration when the focal length of the large aperture miniaturized wide-angle lens according to the first embodiment of the present invention is infinite; Figure 3 is a diagram of spherical aberration, field curvature aberration, and distortion aberration of the large aperture miniaturized wide-angle lens of the first embodiment of the present invention when the focal length is close; Figure 4 is a Rayfan diagram of the large aperture miniaturized wide-angle lens according to the first embodiment of the present invention when the focal length is infinite; Figure 5 is a Rayfan diagram of the large aperture miniaturized wide-angle lens according to the first embodiment of the present invention when the focal length is at a close distance; Figure 6 is an optical structure diagram of a large aperture miniaturized wide-angle lens according to a second embodiment of the present invention; Figure 7 spherical aberration, field curvature aberration, and distortion aberration diagrams of the large aperture miniaturized wide-angle lens according to the second embodiment of the present invention when the focal length is infinite; Figure 8 is a diagram of spherical aberration, field curvature aberration, and distortion aberration of the large aperture miniaturized wide-angle lens of the second embodiment of the present invention when the focal length is close; Fig. 9 is a Rayfan diagram of the large aperture miniaturized wide-angle lens according to the second embodiment of the present invention when the focal length is infinite; Fig.10 is a Rayfan diagram of the large aperture miniaturized wide-angle lens according to the second embodiment of the present invention when the focal length is close; Fig.11 is an optical structure diagram of a large aperture miniaturized wide-angle lens according to Embodiment 3 of the present invention; Fig.12 spherical aberration, field curvature aberration, and distortion aberration diagrams of the large aperture miniaturized wide-angle lens according to the third embodiment of the present invention when the focal length is infinite; Fig.13 spherical aberration, field curvature aberration, and distortion aberration diagrams of the large aperture miniaturized wide-angle lens of the third embodiment of the present invention when the focal length is close; Fig.14 is a Rayfan diagram of the large aperture miniaturized wide-angle lens according to the third embodiment of the present invention when the focal length is infinite; Fig.15 This is a Rayfan diagram of the large aperture miniaturized wide-angle lens according to the third embodiment of the present invention when the focal length is at a close distance. DETAILED DESCRIPTION

[0015] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0016] The large aperture miniaturized wide-angle lens of the present invention comprises, from the object side to the image side, a first lens group with negative refractive power, a second lens group with positive refractive power, and a third lens group with positive refractive power. The focal lengths of the first lens group, the second lens group, and the third lens group satisfy the following conditional equations (4) and (5), so that the refractive power of the third lens group and the second lens group can be balanced, taking into account tolerance sensitivity and performance, and achieving high quality while miniaturizing the entire lens.

[0017] 1≤|EFL_G3 / EFL_G1|≤1.8 (4); 0.8≤|EFL_G3 / EFL_G2|≤1.4 (5); Among them, EFL_G1 is the focal length of the first lens group; EFL_G2 is the focal length of the second lens group; EFL_G3 is the focal length of the third lens group.

[0018] When the focal length ratio of the third lens group to the first lens group exceeds the lower limit of the conditional expression (4) 1≤|EFL_G3 / EFL_G1|≤1.8, the refractive power of the third lens group will be too strong, and the bending angle of the light on each lens will be too large, which will be unfavorable to the tolerance sensitivity of the aberration correction; when the focal length ratio of the third lens group to the first lens group exceeds the upper limit of the conditional expression (4) 1≤|EFL_G3 / EFL_G1|≤1.8, the refractive power of the first lens group will be too strong, and the bending angle of the large-angle light on each lens will be too large, which will place high requirements on the processing of the lenses and make it difficult to maximize the yield.

[0019] When the focal length ratio of the third lens group to the second lens group exceeds the lower limit of the conditional formula (5) 0.8≤|EFL_G3 / EFL_G2|≤1.4, the refractive power of the third lens group will be too strong and the tolerance sensitivity will increase, which is not conducive to mass production. When the focal length ratio of the third lens group to the second lens group exceeds the upper limit of the conditional formula (5) 0.8≤|EFL_G3 / EFL_G2|≤1.4, the refractive power of the second lens group will be too strong and the tolerance sensitivity will increase, which is also not conducive to mass production.

[0020] The first lens group includes a first sub-lens group with negative refractive power and a second sub-lens group with positive refractive power. In order to achieve good correction of various aberrations at a large aperture, the focal lengths of the first sub-lens group and the second sub-lens group satisfy the following condition (7): -12≤EFL_G12 / EFL_G11≤-6 (7); Wherein, EFL_G11 is the focal length of the first sub-lens group; EFL_G12 is the focal length of the second sub-lens group.

[0021] When the focal length ratio of the second sub-lens group to the first sub-lens group exceeds the lower limit of the conditional formula (7) -12≤EFL_G12 / EFL_G11≤-6, the refractive power of the second sub-lens group in the first lens group will be too weak, which is not conducive to the correction of chromatic aberration and spherical aberration under large aperture; when the focal length ratio of the second sub-lens group to the first sub-lens group exceeds the upper limit of the conditional formula (7) -12≤EFL_G12 / EFL_G11≤-6, the refractive power of the first sub-lens group in the first lens group G1 will be too strong, resulting in a large amount of residual aberration, which is not conducive to balancing various aberrations of the rear lens group (i.e., the second lens group G2 and the third lens group G3).

[0022] Preferably, in order to achieve the close aperture of the front lens and the rear lens of the large aperture miniaturized wide-angle lens of the present invention, the aperture is set in the middle of the lens. Specifically, the aperture is set between the second lens group and the third lens group, and the position of the aperture satisfies the following conditional formula (3): 1.6≤L / S_IL≤1.9 (3); Where S_IL is the distance from the aperture to the imaging plane; L is the distance from the object side of the first rod lens of the first lens group to the imaging plane, starting from the object side.

[0023] When the ratio of the distance from the object side of the first lens of the first lens group to the image side of the last lens of the third lens group to the distance from the aperture to the image side of the last lens of the third lens group exceeds the lower limit of the conditional expression (3) 1.6≤L / S_IL≤1.9, the position of the aperture (STOP) will be closer to the object side, resulting in the position of the entrance pupil being closer to the object side, thereby causing the third lens group behind the aperture to become larger, and aberrations are difficult to correct well; when the ratio of the distance from the object side of the first lens of the first lens group to the image side of the last lens of the third lens group to the distance from the aperture to the image side of the last lens of the third lens group exceeds the upper limit of the conditional expression (3) 1.6≤L / S_IL≤1.9, the position of the aperture (STOP) will be closer to the image side, resulting in the position of the entrance pupil being closer to the image side, thereby causing the aperture of the first lens group and the second lens group in front of the aperture to become larger, and it is difficult to achieve miniaturization of the entire lens.

[0024] Preferably, in order to achieve fast focusing and simplified structural design, the second lens group includes a focusing lens, which is used for focusing at long and short distances; the focal length of the focusing lens satisfies the following conditional formula (6): -8.5≤EFL_LF / EFL≤-3.8 (6); Wherein, EFL_LF is the focal length of the focusing lens in the second lens group, and EFL is the focal length of the entire optical system at infinity.

[0025] When the ratio of the focal length of the focusing lens (LF) to the focal length of the entire optical system at infinity exceeds the lower limit of the conditional formula (6) -8.5≤EFL_LF / EFL≤-3.8, the refractive power of the focusing lens (LF) is too low, and the moving distance becomes longer during the focusing process, which is not conducive to fast focusing; when the ratio of the focal length of the focusing lens LF to the focal length of the entire optical system at infinity exceeds the upper limit of the conditional formula (6) -8.5≤EFL_LF / EFL≤-3.8, the refractive power of the focusing lens (LF) is too high, and various aberrations increase too quickly during the focusing process, which is not conducive to close-range focusing.

[0026] The first lens group further includes at least one aspherical lens, preferably a meniscus aspherical lens ASP, the focal length of the aspherical lens is EFL_ASP, and the aspherical lens satisfies the following conditions (1) and (2): -6≤EFL_ASP / EFL≤-2 (1); 1.5≤EFL_ASP / EFL_G11≤4.5 (2); Wherein, EFL is the focal length of the entire optical system at infinity; EFL_G11 is the focal length of the first sub-lens group in the first lens group.

[0027] When the ratio of the focal length of the aspheric lens in the first lens group EFL_ASP to the focal length EFL of the entire optical system at infinity exceeds the lower limit of the conditional expression (1) -6≤EFL_ASP / EFL≤-2, the refractive power of the aspheric lens in the first lens group will be too weak, which is not conducive to the correction of distortion and other aberrations; when the ratio of the focal length of the aspheric lens in the first lens group EFL_ASP to the focal length EFL of the entire optical system at infinity exceeds the upper limit of the conditional expression (1), the refractive power of the aspheric lens in the first lens group will be too strong, the ratio of the center to the edge thickness will be too high, the arc height of the lens will be very large, and the production will be very difficult with the current level of glass aspheric processing, the yield rate will be low, and the assembly sensitivity will be high, and the adjustment will be particularly difficult.

[0028] When the ratio of the focal length of the aspheric lens in the first lens group EFL_ASP to the focal length of the first sub-lens group EFL_G11 exceeds the lower limit of the conditional expression (2) 1.5≤EFL_ASP / EFL_G11≤4.5, the refractive power of the aspheric lens in the first lens group will be too strong, and the refractive index and processing requirements of the aspheric lens will be high; when the ratio of the focal length of the aspheric lens in the first lens group EFL_ASP to the focal length of the first sub-lens group EFL_G11 exceeds the upper limit of the conditional expression (2), the number of lenses in the first lens group will increase and the volume will increase, which is not conducive to miniaturization and weight reduction.

[0029] The shape of the aspheric lens is defined as: r is the radial coordinate from the optical axis; Z is the offset in the direction of the optical axis starting from the intersection of the aspheric surface and the optical axis; c is the curvature of the reference sphere of the aspheric surface; k is the conic coefficient of the aspheric surface; α2 is the fourth-order coefficient of the aspheric surface; α3 is the sixth-order coefficient of the aspheric surface; α4 is the 8th-order coefficient of the aspheric surface; α5 is the 10th-order coefficient of the aspheric surface; α6 is the 12th-order coefficient of the aspheric surface; α7 is the 14th-order coefficient of the aspheric surface; and, .

[0030] Compared with the prior art, the present invention, through the above scheme, makes a large aperture miniaturized wide-angle lens have excellent optical performance, and at the same time, by arranging a strong refractive power aspheric lens in the first lens group, the volume of the first lens group is reduced, and the lens has the advantages of large aperture, fixed focal length and wide angle of the aspheric surface, thereby achieving a wide-angle effect, and by arranging the aperture at a position relatively close to the object side, the entrance pupil position is brought forward, achieving the purpose of miniaturization and wide angle, so that the photographic lens of the present invention can achieve wide angle, large aperture and fast focus on a movie camera with a long flange distance.

[0031] In addition, the third lens group includes at least one aspherical lens, and the focal length of the aspherical lens of the third lens group satisfies the following conditional formula: By adding an aspherical lens to the third lens group, the distortion is further reduced, the distortion caused by the wide-angle lens is reduced, and the field curvature is controlled, thereby improving the lens performance.

[0032] The large aperture miniaturized wide-angle lens of the present invention is further described below through embodiments and comparative examples. Example

[0033] like Figure 1 As shown, the large aperture miniaturized wide-angle lens of the first embodiment of the present invention includes a first lens group G1 with negative refractive power, a second lens group G2 with positive refractive power, and a third lens group G3 with positive refractive power from the object side to the image side; the aperture (Stop) is arranged between the second lens group G2 and the third lens group G3; the first lens group G1 is composed of lenses L11 to L16 arranged in sequence from the object side to the image side, wherein the lenses L11 and L12 constitute the first sub-lens group G11, and the lenses L13 to L16 constitute the second sub-lens group G12; the second lens group G2 is composed of a focusing lens LF, a lens L22, and a lens L23 arranged in sequence from the object side to the image side, and the third lens group G3 is composed of lenses L31 to L37 arranged in sequence from the object side to the image side. When the object moves from infinity to a close distance, the focusing lens LF in the second lens group G2 moves to achieve focusing.

[0034] The structure of the optical system in the large aperture miniaturized wide-angle lens of the first embodiment is specifically shown in Table 1 below.

[0035] Table 1 Lens surface RDY THI Refractive index Nd Abbe number Vd Object side of lens L11 40.11 2.20 1.8042 46.50 Image side of lens L11 19.79 5.63 Object side of lens L12 34.38 2.2 1.5883 61.28 Image side of lens L12 17.07 10.63 Object side of lens L13 -57.09 2.20 1.5503 75.49 The image side surface of lens L13 and the object side surface of lens L14 38.92 6.48 2.0508 26.94 Image side of lens L14 -154.28 1.50 Object side of lens L15 -51.06 2.20 1.9459 17.98 The image side surface of lens L15 and the object side surface of lens L16 107.90 4.83 2.0010 29.13 Image side of lens L16 -85.60 3.57 Object side of focusing lens LF -41.16 2.20 1.5927 35.44 Image side of focusing lens LF -81.26 0.10 Object side of lens L22 34.01 8.66 1.5503 75.49 Image side of lens L22 -67.06 3.42 Object side of lens L23 74.51 3.96 1.9861 16.48 Image side of lens L23 372.96 1.92 Aperture surface infinity 2.37 Object side of lens L31 -94.88 5.94 1.5503 75.49 The image side surface of lens L31 and the object side surface of lens L32 -21.31 2.20 1.8830 40.80 Image side of lens L32 -129.57 3.27 Object side of lens L33 -16.14 2.39 1.8088 40.97 Image side of lens L33 -20.88 2.37 Object side of lens L34 340.55 9.34 1.5503 75.49 Image side of lens L34 -25.42 0.01 Object side of lens L35 -51.18 5.58 1.5503 75.49 Image side of lens L35 -31.58 0.01 Object side of lens L36 298.24 2.20 1.9515 29.82 The image side surface of lens L36 and the object side surface of lens L37 35.22 12.42 1.5928 68.62 Image side of lens L37 -49.88 31.0 Protect the object side of the glass lens infinity 0.1 1.5168 64.16 Protect the image side of the glass lens infinity 0.1 In Table 1, RDY (mm) is the radius of curvature of the lens surface, THI (mm) is the distance between the lenses and the thickness of the lenses, Nd is the refractive index of each lens of the d line, and Vd is the Abbe number of the lens. The focal length of the entire optical system is 18.6, and the aperture coefficient (Fno) is 1.43.

[0036] The values ​​corresponding to various coefficients of the aspherical lens in the first embodiment are shown in Table 2 below.

[0037] Table 2 Lens surface K <![CDATA[α2]]> <![CDATA[α3]]> <![CDATA[α4]]> <![CDATA[α5]]> <![CDATA[α6]]> <![CDATA[α7]]> Object side of lens L12 0 2.5784e-05 -1.1013e-07 3.5258e-10 -5.5802e-13 4.3538e-16 Image side of lens L12 -1.71 4.9871e-05 -1.4641e-07 2.5970e-10 7.7728e-14 -1.0243e-15 Object side of lens L33 0 8.0594e-05 4.4034e-07 -3.9528e-09 1.3325e-11 -1.1642e-14 Image side of lens L33 0 8.1216e-05 3.8245e-07 -3.0718e-09 9.0172e-12 -9.9449e-15 When THI(10) and THI(12) are equal to different values, the corresponding imaging distances are shown in Table 3, corresponding to infinity and 250 mm respectively.

[0038] Table 3 Photo distance ∞ 250mm THI(10) 3.567 1.4838 THI(12) 0.100 2.1829 After testing, the spherical aberration, field curvature and distortion of the large aperture miniaturized wide-angle lens described in the first embodiment when focusing at infinity are as follows: Figure 2 As shown, the Rayfan of each field of view is as follows Figure 4 As shown in the figure, the spherical aberration, field curvature and distortion when focusing at close distance are as follows Figure 3 As shown, the Rayfan of each field of view is as follows Figure 5 shown. Example

[0039] like Figure 6As shown, the large aperture miniaturized wide-angle lens of the second embodiment of the present invention includes a first lens group G1 with negative refractive power, a second lens group G2 with positive refractive power, and a third lens group G3 with positive refractive power from the object side to the image side; the aperture (Stop) is arranged between the second lens group G2 and the third lens group G3; the first lens group G1 is composed of lenses L11 to L17 arranged in sequence from the object side to the image side, wherein the lenses L11 to L3 constitute the first sub-lens group G11, and the lenses L14 to L17 constitute the second sub-lens group G12; the second lens group G2 is composed of lenses L21, focusing lens LF, and lens L23 arranged in sequence from the object side to the image side, and the third lens group G3 is composed of lenses L31 to L38 arranged in sequence from the object side to the image side. When the object moves from infinity to a close distance, the focusing lens LF in the second lens group G2 moves to achieve focusing.

[0040] The structure of the optical system in the large aperture miniaturized wide-angle lens of the second embodiment is specifically shown in Table 4 below.

[0041] Table 4 Lens surface RDY THI Refractive index Nd Abbe number Vd Object side of lens L11 44.04 1.7 1.8040 46.57 Image side of lens L11 22.19 6.10 Object side of lens L12 31.17 1.70 1.9228 20.88 Image side of lens L12 23.16 3.07 Object side of lens L13 39.41 3.30 1.4965 81.53 Image side of lens L13 20.83 9.88 Object side of lens L14 -46.53 1.7 1.5503 75.49 The image side surface of lens L14 and the object side surface of lens L15 37.80 7.41 1.7303 32.23 Image side of lens L15 -118.00 1.73 Object side of lens L16 40.77 8.46 1.6989 30.05 The image side surface of lens L16 and the object side surface of lens L17 -31.65 1.70 1.9228 18.89 Image side of lens L17 124.40 1.05 The object side adjustment of lens L21 -645.77 3.04 1.6476 33.84 The image side of lens L21 is adjusted -94.40 3.74 Object side of focusing lens LF -60.36 1.7 1.7858 43.93 Image side of the focal lens LF -163.29 0.15 Object side of lens L23 42.77 6.39 1.8696 20.01 Image side of lens L23 -89.55 1.50 Aperture surface infinity 3.95 Object side of lens L31 103.38 6.96 1.5503 75.49 The image side surface of lens L31 and the object side surface of lens L32 -23.58 1.70 1.7282 28.32 Image side of lens L32 119.58 5.68 Object side of lens L33 -11.29 2.26 1.9515 29.82 Image side of lens L33 -15.33 0.94 Object side of lens L34 9369.69 8.96 1.4965 81.53 Image side of lens L34 -22.90 0.15 Object side of lens L35 -66.16 5.95 1.5503 75.49 Image side of lens L35 -30.71 0.15 Object side of lens L36 -130.40 1.70 1.8545 25.15 Image side of lens L36 76.19 0.62 Object side of lens L37 95.24 8.89 1.5503 75.49 Image side of lens L37 -47.23 0.10 Object side of lens L38 -104.16 3.55 1.8697 20.01 Image side of lens L38 -66.11 33.2 Protect the object side of the glass lens infinity 2.8 1.5168 64.16 Protect the image side of the glass lens infinity 0.1 In Table 4, RDY (mm) is the radius of curvature of the lens surface, THI (mm) is the distance between each lens and the thickness of the lens, Nd is the refractive index of each lens of the d line, and Vd is the Abbe number of the lens. The focal length of the entire optical system is 18.6, and the aperture coefficient (Fno) is 1.50.

[0042] The values ​​corresponding to various coefficients of the aspherical lens in the second embodiment are shown in Table 5 below.

[0043] Table 5 Lens surface K <![CDATA[α2]]> <![CDATA[α3]]> <![CDATA[α4]]> <![CDATA[α5]]> <![CDATA[α6]]> <![CDATA[α7]]> Object side of lens L13 0 3.1597e-05 -1.0689e-07 2.7986e-10 -3.3530e-13 Image side of lens L13 0 1.1185e-05 -1.7835e-07 3.3977e-10 -6.7704e-13 Object side of lens L33 -1.01 7.6603e-05 8.2952e-07 -1.0253e-08 4.4065e-11 -7.2322e-14 Image side of lens L33 -0.93 9.0796e-05 6.2620e-07 -5.8838e-09 1.8979e-11 -1.8973e-14 -1.4807e-17 When THI(10) and THI(12) are equal to different values, the corresponding imaging distances are shown in Table 6, corresponding to infinity and 250 mm respectively.

[0044] Table 6 Photo distance ∞ 250mm THI(14) 3.73 2.23 THI(16) 0.15 1.65 After testing, the spherical aberration, field curvature and distortion of the large aperture miniaturized wide-angle lens described in the second embodiment when focusing at infinity are as follows: Figure 7 As shown, the Rayfan of each field of view is as follows Fig. 9 As shown in the figure, the spherical aberration, field curvature and distortion when focusing at close distance are as follows Figure 8 As shown, the Rayfan of each field of view is as follows Fig.10 shown. Example

[0045] like Fig.11As shown, the large aperture miniaturized wide-angle lens of the third embodiment of the present invention includes a first lens group G1 with negative refractive power, a second lens group G2 with positive refractive power, and a third lens group G3 with positive refractive power from the object side to the image side; the aperture (Stop) is arranged between the second lens group G2 and the third lens group G3; the first lens group G1 is composed of lenses L11 to L16 arranged in sequence from the object side to the image side, wherein the lenses L11 to L13 constitute the first sub-lens group G11, and the lenses L14 to L16 constitute the second sub-lens group G12; the second lens group G2 is composed of a focus lens LF, a lens L22, and a lens L23 arranged in sequence from the object side to the image side, and the third lens group G3 is composed of lenses L31 to L38 arranged in sequence from the object side to the image side. When the object moves from infinity to a close distance, the lens LF in the second lens group G2 moves to achieve focusing.

[0046] The structure of the optical system in the large aperture miniaturized wide-angle lens described in the third embodiment is specifically shown in Table 7 below.

[0047] Table 7 Lens surface RDY THI Refractive index Nd Abbe number Vd Object side of lens L11 45.00 2.12 1.9108 35.25 Image side of lens L11 23.61 6.26 Object side of lens L12 30.55 2.63 1.9108 35.25 Image side of lens L12 23.41 4.04 Object side of lens L13 62.24 3.53 1.5891 61.25 Image side of lens L13 26.69 10.06 Object side of lens L14 -42.35 1.72 1.4370 95.10 The image side surface of lens L14 and the object side surface of lens L15 36.11 11.33 1.8545 25.15 The image side surface of lens L15 and the object side surface of lens L16 -28.98 2.21 1.9459 17.98 Image side of lens L16 -130.23 7.12 Object side of focusing lens LF -45.86 1.72 1.9537 32.31 Image side of focusing lens LF -113.04 0.54 Object side of lens L22 37.12 7.23 1.5503 75.49 Image side of lens L22 -118.35 0.15 Object side of lens L23 79.27 4.34 1.9459 17.98 Image side of lens L23 -407.37 1.61 Aperture surface infinity 3.12 Object side of lens L31 86.38 7.25 1.4370 95.10 The image side surface of lens L31 and the object side surface of lens L32 -25.06 3.02 1.7704 29.73 Image side of lens L32 -181.44 7.12 Object side of lens L33 -12.01 3.04 1.8088 40.97 Image side of lens L33 -17.40 1.46 Object side of lens L34 163.91 8.70 1.4370 95.10 Image side of lens L34 -27.66 0.15 Object side of lens L35 -255.97 7.32 1.5503 75.49 Image side of lens L35 -34.28 0.15 Object side of lens L36 -997.14 1.70 1.9537 32.31 Image side of lens L36 54.77 3.15 Object side of lens L37 472.32 5.82 1.5503 75.49 Image side of lens L37 -62.66 0.15 Object side of lens L38 179.61 5.33 1.5928 68.62 Image side of lens L38 -95.92 33.11 Protect the object side of the glass lens infinity 2.81 1.5168 64.16 Protect the image side of the glass lens infinity 0.1 In Table 7, RDY (mm) is the radius of curvature of the lens surface, THI (mm) is the distance between each lens and the thickness of the lens, Nd is the refractive index of each lens of the d line, and Vd is the Abbe number of the lens. The focal length of the entire optical system is 18.6, and the aperture coefficient (Fno) is 1.55.

[0048] The values ​​corresponding to various coefficients of the aspherical lens in the second embodiment are shown in Table 8 below.

[0049] Table 8 Lens surface K <![CDATA[α2]]> <![CDATA[α3]]> <![CDATA[α4]]> <![CDATA[α5]]> <![CDATA[α6]]> <![CDATA[α7]]> Object side of lens L13 0 5.3017e-5 -1.8956e-7 5.5099e-10 -9.6779e-13 7.2671e-16 Image side of lens L13 0.75 3.9440e-05 -2.3971e-07 4.8772e-10 -8.3866e-13 1.7088e-16 Object side of lens L33 -1.08 5.4692e-05 4.3360e-07 -4.0021e-09 1.1736e-11 -4.7118e-15 -2.6676e-17 Image side of lens L33 -1.45 5.8474e-05 3.3557e-07 -2.3910e-09 6.1563e-12 -5.4322e-15 -2.0798e-18 When THI(10) and THI(12) are equal to different values, the corresponding imaging distances are shown in Table 9, corresponding to infinity and 250 mm respectively.

[0050] Table 9 Photo distance ∞ 250mm THI(10) 7.12 5.60 THI(12) 0.54 2.03 After testing, the spherical aberration, field curvature and distortion of the large aperture miniaturized wide-angle lens described in the third embodiment when focusing at infinity are as follows: Fig.12 As shown, the Rayfan of each field of view is as follows Fig.14 As shown in the figure, the spherical aberration, field curvature and distortion when focusing at close distance are as follows Fig.13 As shown, the Rayfan of each field of view is as follows Fig.15 shown.

[0051] Furthermore, the large aperture miniaturized wide-angle lenses described in Embodiments 1 to 3 of the present invention satisfy the following conditions (1) to (7), as shown in Table 10.

[0052] Table 10 Embodiment 1 Embodiment 2 Embodiment 3 Conditional formula (1): -6 ≤ EFL_ASP / EFL ≤ -2 -3.25 -5.08 -4.42 Conditional formula (2): 1.5 ≤ EFL_ASP / EFL_G11 ≤ 4.5 2.38 4.08 3.49 Conditional expression (3): 1.6≤L / S_IL≤1.9 1.78 1.73 1.71 Conditional formula (4): 1≤|EFL_G3 / EFL_G1|≤1.8 1.28 1.69 1.39 Conditional formula (5): 0.8≤|EFL_G3 / EFL_G2|≤1.4 1.18 1.26 1 Conditional expression (6): -8.5≤EFL_LF / EFL≤-3.8 -7.72 -6.6 -4.4 Conditional formula (7): -12 ≤ EFL_G12 / EFL_G11 ≤ -6 -8.94 -11.78 -7.62 It can be seen from the above embodiments 1 to 3 that the photographic lens has a large aperture, a long flange focal distance, a single-element focusing, and excellent optical performance, and can achieve wide angle, large aperture, and fast focusing on a movie camera with a long flange focal distance.

[0053] The above is a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A large aperture miniaturized wide-angle lens, characterized in that: The lens system includes, from the object side to the image side, a first lens group with negative refractive power, a second lens group with positive refractive power, and a third lens group with positive refractive power; wherein, The first lens group comprises a first sub-lens group with negative refractive power and a second sub-lens group with positive refractive power; An aperture is provided between the second lens group and the third lens group, and the second lens group includes a focusing lens, which is used for focusing at long and short distances; The first lens group further includes at least one aspherical lens, the focal length of the aspherical lens is EFL_ASP, and satisfies the following conditional formula: -6≤EFL_ASP / EFL≤-2; 1.5≤EFL_ASP / EFL_G11≤4.5; Wherein, EFL is the focal length of the entire optical system at infinity; EFL_G11 is the focal length of the first sub-lens group in the first lens group.

2. The large aperture miniaturized wide-angle lens according to claim 1, characterized in that: The position of the aperture satisfies the following condition: 1.6≤L / S_IL≤1.9; Where S_IL is the distance from the aperture to the imaging plane; L is the distance from the object side of the first rod lens of the first lens group to the imaging plane, starting from the object side.

3. The large aperture miniaturized wide-angle lens according to claim 2, characterized in that: The focal lengths of the first lens group, the second lens group and the third lens group satisfy the following conditional formula: 1≤|EFL_G3 / EFL_G1|≤1.8; 0.8≤|EFL_G3 / EFL_G2|≤1.4; Among them, EFL_G1 is the focal length of the first lens group; EFL_G2 is the focal length of the second lens group; EFL_G3 is the focal length of the third lens group.

4. The large aperture miniaturized wide-angle lens according to claim 3, characterized in that: The focal length of the focusing lens in the second lens group satisfies the following conditional formula: -8.5≤EFL_LF / EFL≤-3.8; Wherein, EFL_LF is the focal length of the focusing lens in the second lens group, and EFL is the focal length of the entire optical system at infinity.

5. The large aperture miniaturized wide-angle lens according to claim 4, characterized in that: The focal lengths of the first sub-lens group and the second sub-lens group in the first lens group satisfy the following conditional formula: -12≤EFL_G12 / EFL_G11≤-6; Wherein, EFL_G11 is the focal length of the first sub-lens group; EFL_G12 is the focal length of the second sub-lens group.

6. The large aperture miniaturized wide-angle lens according to any one of claims 1 to 5, characterized in that: The third lens group includes at least one aspherical lens.

7. The large aperture miniaturized wide-angle lens according to claim 5, characterized in that: The first lens group is composed of lenses L11 to L16 arranged in sequence from the object side to the image side, wherein the lenses L11 and L12 constitute a first sub-lens group, the lenses L13 to L16 constitute a second sub-lens group, the second lens group is composed of a focus lens LF, a lens L22, and a lens L23 arranged in sequence from the object side to the image side, and the third lens group is composed of lenses L31 to L37 arranged in sequence from the object side to the image side; Moreover, the focal length of the aspheric lens in the first lens group is EFL_ASP, which has a ratio of -3.25 to the focal length EFL of the entire optical system at infinity, and a ratio of 2.38 to the focal length EFL_G11 of the first sub-lens group; the ratio of the distance from the object side of the lens L11 to the image side of the lens L37 to the distance from the aperture to the image side of the lens L37 is 1.78; the ratios of the focal lengths of the third lens group to the first lens group and the second lens group are 1.28 and 1.18 respectively; the ratio of the focal length of the focusing lens LF in the second lens group to the focal length of the entire optical system at infinity is -7.72; and the ratio of the focal lengths of the second sub-lens group to the first sub-lens group is -8.

94.

8. The large aperture miniaturized wide-angle lens according to claim 5, characterized in that: The first lens group is composed of lenses L11 to L17 arranged in sequence from the object side to the image side, wherein the lenses L11 to L3 constitute a first sub-lens group, the lenses L14 to L17 constitute a second sub-lens group, the second lens group is composed of a lens L21, a focusing lens LF, and a lens L23 arranged in sequence from the object side to the image side, and the third lens group is composed of lenses L31 to L38 arranged in sequence from the object side to the image side; Moreover, the focal length of the aspheric lens in the first lens group is EFL_ASP, which has a ratio of -5.08 to the focal length EFL of the entire optical system at infinity, and a ratio of 4.08 to the focal length EFL_G11 of the first sub-lens group; the ratio of the distance from the object side of the lens L11 to the image side of the lens L38 to the distance from the aperture to the image side of the lens L38 is 1.73; the focal length ratios of the third lens group to the first lens group and the second lens group are 1.69 and 1.26 respectively; the ratio of the focal length of the focusing lens LF in the second lens group to the focal length of the entire optical system at infinity is -6.6; the ratio of the focal length of the second sub-lens group to the first sub-lens group is -11.

78.

9. The large aperture miniaturized wide-angle lens according to claim 5, characterized in that: The first lens group is composed of lenses L11 to L16 arranged in sequence from the object side to the image side, wherein the lenses L11 to L13 constitute a first sub-lens group, the lenses L14 to L16 constitute a second sub-lens group, the second lens group is composed of a focus lens LF, a lens L22, and a lens L23 arranged in sequence from the object side to the image side, and the third lens group is composed of lenses L31 to L38 arranged in sequence from the object side to the image side; Moreover, the focal length of the aspheric lens in the first lens group is EFL_ASP, which has a ratio of -4.42 to the focal length EFL of the entire optical system at infinity, and a ratio of 3.49 to the focal length EFL_G11 of the first sub-lens group; the ratio of the distance from the object side of the lens L11 to the image side of the lens L38 to the distance from the aperture to the image side of the lens L38 is 1.71; the focal length ratios of the third lens group to the first lens group and the second lens group are 1.39 and 1 respectively; the focal length of the focusing lens LF in the second lens group has a ratio of -4.4 to the focal length of the entire optical system at infinity; the ratio of the focal length of the second sub-lens group to the first sub-lens group is -7.62.

Images