A large-field small-size wide-angle lens

Abstract

This utility model relates to a miniaturized wide-angle lens with a large image field. From the object side to the image plane, it sequentially 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. The first lens group G1 consists of a first sub-lens group G11 with negative refractive power and a second sub-lens group G12 with positive refractive power. The second lens group G2 includes an LF lens, which serves as a focusing lens. An aperture stop is positioned between the second lens group G2 and the third lens group G3. Both the first lens group G1 and the third lens group G3 include at least one aspherical lens, and the focal length of the aspherical lens in the first lens group G1 satisfies the condition 1.5 ≤ EFL_ASP / EFL_G1 ≤ 4.0, where EFL_ASP and EFL_G1 are the focal lengths of the aspherical lens in the first lens group G1 and the focal length of the first lens group G1, respectively. This lens has the advantages of a large aperture, fixed focal length, large image field, and wide angle, exhibiting excellent optical performance.

Description

Technical Field

[0001] This utility model belongs to the field of photographic lens technology, and specifically relates to a miniaturized wide-angle lens with a large image field. Background Technology

[0002] In recent years, digital photography equipment has been widely used, and the quality requirements for video shooting are getting higher and higher. This has also placed higher demands on the image circle size that photography equipment can cover. The full-frame image circle can no longer meet the needs of some higher-end photography. Currently, most wide-angle lenses on the market can only cover full-frame sensors. Lenses that can cover larger sensor sizes have problems such as longer focal lengths, smaller apertures, and obvious vignetting at the edges. Utility Model Content

[0003] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention provides a miniaturized wide-angle lens with a large image field. This lens can cover a larger image field and its aperture is further improved.

[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: This invention provides a miniaturized wide-angle lens with a large image field, comprising, from the object side to the image plane, 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; wherein... The first lens group G1 consists of a first sub-lens group G11 with negative refractive power and a second sub-lens group G12 with positive refractive power; the second lens group G2 includes an LF lens, which serves as a focusing lens for focusing at both near and far distances; an aperture STOP is provided between the second lens group G2 and the third lens group G3. Both the first lens group G1 and the third lens group G3 contain at least one aspherical lens, wherein the focal length of the aspherical lens in the first lens group G1 satisfies the following condition: 1.5 ≤ EFL_ASP / EFL_G1 ≤ 4.0 In the formula, EFL_ASP is the focal length of the aspherical lens in the first lens group G1; EFL_G1 is the focal length of the first lens group G1.

[0005] In one embodiment of this invention, the position of the aperture STOP satisfies the following condition: 2.2≤L / L1_S≤3.5 In the formula, L1_S is the distance from the object side to the aperture stop; L is the distance from the first surface to the image plane from the object side.

[0006] In one embodiment of this invention, the focal lengths of the first lens group G1, the second lens group G2, and the third lens group G3 satisfy the following condition: -2.6 ≤ |EFL_G3 / EFL_G1| ≤ -1.8 -3.3 ≤ |EFL_G2 / EFL_G1| ≤ -1.8 In the formula, EFL_G1 is the focal length of the first lens group G1, EFL_G2 is the focal length of the second lens group G2, and EFL_G3 is the focal length of the third lens group G3.

[0007] In one embodiment of this invention, the LF lens in the second lens group G2 satisfies the following condition: -3.1 ≤ EFL_LF / EFL ≤ -2.1 In the formula, EFL is the focal length of the entire optical system at infinity; EFL_LF is the focal length of the LF lens in the second lens group G2.

[0008] In one embodiment of this invention, the first sub-lens group G11 and the second sub-lens group G12 in the first lens group G1 satisfy the following condition: -42≤EFL_G12 / EFL_G11≤-14 In the formula, EFL_G11 is the focal length of the first sub-lens group G11, and EFL_G12 is the focal length of the second sub-lens group G12.

[0009] In one embodiment of this invention, the third lens group G3 and the maximum image height at infinity satisfy the following condition: 0.40≤│y'Max / EFL_G3│≤ 0.80 In the formula, EFL_G3 is the focal length of the third lens group G3, y'Max is the maximum paraxial image height at infinity, y'Max = EFL × tanω, and ω is the half-angle of the entire optical system at infinity.

[0010] In one embodiment of this invention, the third lens group G3 is composed of 10 lenses L31 to L310 arranged sequentially from the object side toward the image plane, including at least two sets of cemented doublet lenses and one set of cemented triplet lenses; or, the third lens group G3 is composed of 11 lenses L31 to L311 arranged sequentially from the object side toward the image plane, including at least three sets of cemented doublet lenses.

[0011] In one embodiment of this utility model, when the third lens group G3 is composed of 10 lenses, lenses L31 and L32, lenses L33 and L34 respectively constitute cemented doublet lenses, and lenses L36, L37 and L38 constitute cemented triplet lenses. When the third lens group G3 consists of 11 lenses, lenses L31 and L32, lenses L33 and L34, and lenses L36 and L37 respectively constitute cemented doublet lenses.

[0012] In one embodiment of this invention, the first lens group G1 is composed of lenses L11 to L14 arranged sequentially from the object side toward the image plane, wherein lens L11 and lens L12 constitute the first sub-lens group G11, and lens L13 and lens L14 constitute the second sub-lens group G12, and lens L12 is an aspherical lens.

[0013] In one embodiment of this invention, the second lens group G2 is composed of an LF lens and a lens L22 arranged sequentially from the object side toward the image plane.

[0014] The beneficial effects of this utility model are: Through the above-mentioned technical solution, this utility model enables the lens to have the advantages of large aperture, fixed focal length, large image circle, and wide angle. It is an imaging lens with large aperture, large image circle, single-element focusing, and excellent optical performance, which can achieve wide-angle and fast focusing on large image circle photographic equipment. Attached Figure Description

[0015] Figure 1 This is an optical structure diagram of the miniaturized wide-angle lens with a large image field as described in Embodiment 1 of the present invention; Figure 2 This is a diagram of spherical aberration, field curvature aberration, and distortion aberration of the miniaturized wide-angle lens with a large image field as described in Embodiment 1 of the present invention when the focal length is at infinity; Figure 3 This is a diagram showing the spherical aberration, field curvature aberration, and distortion aberration of the miniaturized wide-angle lens with a large image field as described in Embodiment 1 of the present invention at a close focal length; Figure 4 This is a Rayfan diagram of the large image field miniaturized wide-angle lens described in Embodiment 1 of the present invention when the focal length is infinity; Figure 5 This is a Rayfan diagram of the large image field miniaturized wide-angle lens described in Embodiment 1 of the present invention at a close focal length; Figure 6 This is an optical structure diagram of the miniaturized wide-angle lens with a large image field as described in Embodiment 2 of the present invention; Figure 7 This is a diagram of spherical aberration, field curvature aberration, and distortion aberration of the miniaturized wide-angle lens with a large image field as described in Embodiment 2 of the present invention when the focal length is at infinity; Figure 8 This is a diagram showing the spherical aberration, field curvature aberration, and distortion aberration of the miniaturized wide-angle lens with a large image field as described in Embodiment 2 of the present invention at a close focal length; Figure 9This is a Rayfan diagram of the large image field miniaturized wide-angle lens described in Embodiment 2 of the present invention when the focal length is infinity; Figure 10 This is a Rayfan diagram of the large image field miniaturized wide-angle lens described in Embodiment 2 of the present invention at a close focal length; Figure 11 This is an optical structure diagram of the miniaturized wide-angle lens with a large image field as described in Embodiment 3 of the present invention; Figure 12 This is a diagram of spherical aberration, field curvature aberration, and distortion aberration of the miniaturized wide-angle lens with a large image field as described in Embodiment 3 of the present invention when the focal length is at infinity; Figure 13 This is a diagram showing the spherical aberration, field curvature aberration, and distortion aberration of the miniaturized wide-angle lens with a large image field as described in Embodiment 3 of the present invention at a close focal length; Figure 14 This is a Rayfan diagram of the large image field miniaturized wide-angle lens described in Embodiment 3 of the present invention when the focal length is infinity; Figure 15 This is a Rayfan diagram of the large image field miniaturized wide-angle lens described in Embodiment 3 of the present invention at a close focal length. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this utility model and are not intended to limit this utility model.

[0017] This utility model discloses a miniaturized wide-angle lens with a large image field, comprising, from the object side to the image plane, 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. The first lens group G1 consists of a first sub-lens group G11 with negative refractive power and a second sub-lens group G12 with positive refractive power. The second lens group G2 includes an LF lens, which serves as a focusing lens for focusing at both near and far distances. An aperture stop is positioned between the second lens group G2 and the third lens group G3.

[0018] Furthermore, both the first lens group G1 and the third lens group G3 contain at least one aspherical lens. The focal length of the aspherical lens in the first lens group G1 satisfies the condition (1): 1.5 ≤ EFL_ASP / EFL_G1 ≤ 4.0, where EFL_ASP is the focal length of the aspherical lens in the first lens group G1, and EFL_G1 is the focal length of the first lens group G1. If the lower limit of condition (1) is exceeded, the refractive power of the aspherical lens in the first lens group G1 will be too weak, which is not conducive to the correction of distortion and other aberrations. If the upper limit of condition (1) is exceeded, the refractive power of the aspherical lens in the first lens group G1 will be too strong, the center and edge thickness ratio will be too high, and the arc height of the lens will be very large. With the current level of glass aspherical processing, production is very difficult, the yield rate is low, and the assembly sensitivity is high, making assembly and adjustment particularly difficult.

[0019] In order to make the aperture STOP of the front and rear lenses similar, the aperture STOP needs to be located in the front of the middle of the lens. Therefore, the position of the aperture STOP of this utility model satisfies the condition (2): 2.2≤L / L1_S≤3.5, where L1_S is the distance from the object side to the aperture STOP; L is the distance from the first surface to the image plane from the object side (i.e., the distance from the object side of the first lens of the first lens group G1 to the image plane). If the lower limit of condition (2) is exceeded, the aperture stop position will be closer to the object side, which is beneficial to the miniaturization of the first lens group G1 and the second lens group G2, but it will cause the entrance pupil position to be closer to the object side, causing the third lens group G3 behind the aperture stop to become larger rapidly, making it difficult to correct aberrations well; if the upper limit of condition (2) is exceeded, the aperture stop position will be closer to the image side, which is beneficial to the miniaturization of the third lens group G3, but it will cause the entrance pupil position to be closer to the image side, causing the apertures of the first lens group G1 and the second lens group G2 in front of the aperture stop to become larger, making it difficult to achieve miniaturization of the entire lens.

[0020] Preferably, in order to achieve miniaturization and high quality of the entire lens, the focal lengths of the first lens group G1, the second lens group G2, and the third lens group G3 satisfy the conditions (3): -2.6≤|EFL_G3 / EFL_G1|≤-1.8 and (4): -3.3≤|EFL_G2 / EFL_G1|≤-1.8, where EFL_G1 is the focal length of the first lens group G1, EFL_G2 is the focal length of the second lens group G2, and EFL_G3 is the focal length of the third lens group G3. If the upper limit of condition (3) is exceeded, the refractive power of the third lens group G3 will be too strong, and the bending angle of light on each lens will be too large, which is detrimental to aberration correction and tolerance sensitivity. If the lower limit of condition (3) is exceeded, the refractive power of the first lens group G1 will be too strong, and the bending angle of large-angle light on the lens will be too large, which will require higher processing of the lens and make it difficult to maximize the yield. If the upper limit of condition (4) is exceeded, the refractive power of the second lens group G2 will be too strong, and the tolerance sensitivity will also increase, which is detrimental to mass production; if the lower limit of condition (4) is exceeded, the refractive power of the first lens group G1 will be too strong, and the tolerance sensitivity will also increase, which is detrimental to mass production. Therefore, in order to optimize lens performance, this utility model balances the refractive power of the third lens group G3 and the second lens group G2, taking into account both tolerance sensitivity and performance optimization, and simultaneously satisfies the conditions (3) and (4) for the focal lengths of the first lens group G1, the second lens group G2 and the third lens group G3.

[0021] In another preferred embodiment, in order to achieve fast focusing and simplified structural design, the focusing lens of this invention uses the LF lens in the second lens group G2 to move along the optical axis to achieve focusing. The LF lens satisfies the condition (5): -3.1≤EFL_LF / EFL≤-2.1, where EFL is the focal length of the entire optical system at infinity; EFL_LF is the focal length of the LF lens in the second lens group G2. If the lower limit of condition (5) is exceeded, the refractive power of the focusing lens (LF lens) is too low, and the movement distance during focusing becomes longer, which is not conducive to fast focusing; if the upper limit of condition (5) is exceeded, the refractive power of the focusing lens (LF lens) is too high, and various aberrations increase too quickly during focusing, which is not conducive to close-range focusing.

[0022] In another preferred embodiment, in order to achieve good correction of various aberrations at large apertures, the first sub-lens group G11 and the second sub-lens group G12 in the first lens group G1 of this invention satisfy the condition (6): -42≤EFL_G12 / EFL_G11≤-14, where EFL_G11 is the focal length of the first sub-lens group G11 and EFL_G12 is the focal length of the second sub-lens group G12. If the lower limit of condition (6) is exceeded, the refractive power of the second sub-lens group G12 in the first lens group G1 will be too weak, which is not conducive to the correction of chromatic aberration and spherical aberration at large apertures; if the upper limit of condition (6) is exceeded, the refractive power of the first sub-lens group G11 in the first lens group G1 will be too strong, generating a large number of residual aberrations, which is not conducive to the balance of various aberrations in the rear lens group.

[0023] The third lens group G3 of this utility model can be composed of 10 lenses, including at least two sets of cemented doublet lenses and one set of cemented triplet lenses; the third lens group G3 can also be composed of 11 lenses, including at least three sets of cemented doublet lenses; and the maximum image height of the third lens group G3 and the infinity state satisfies the condition (7): 0.40≤│y'Max / EFL_G3│≤ 0.80, where EFL_G3 is the focal length of the third lens group G3, y'Max is the paraxial maximum image height in the infinity state, y'Max=EFL×tanω, and ω is the half-angle of the entire optical system in the infinity state.

[0024] Compared with existing wide-angle lenses, this new lens has the advantages of large aperture, fixed focal length, large image circle, and wide angle. It is an imaging lens with large aperture, large image circle, single-element focusing, and excellent optical performance, which can achieve wide-angle and fast focusing on large image circle photographic equipment.

[0025] The following examples further illustrate the large image field miniaturized wide-angle lens of this invention. Example 1

[0026] like Figure 1 As shown, the miniaturized wide-angle lens with a large image field described in Embodiment 1 of this utility model comprises, from the object side to the image side, 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; the aperture stop is set between the second lens group G2 and the third lens group G3; the first lens group G1 is composed of lenses L11 to L14 arranged sequentially from the object side to the image side, wherein lenses L11 and L12 constitute the first sub-lens group G11, and lenses L13 and L14 constitute the second sub-lens group G12; the second lens group G2 is composed of a focusing lens (LF lens) and lens L22 arranged sequentially from the object side to the image side; and the third lens group G3 is composed of lenses L31 to L310 arranged sequentially from the object side to the image side.

[0027] When the lens described in Embodiment 1 is used, as an object moves from infinity to near, focusing is achieved by moving the focusing lens (LF lens) in the second lens group G2. Testing showed that the lens described in Embodiment 1 exhibits the following characteristics when focusing at infinity: spherical aberration, field curvature, and distortion are as follows: Figure 2 As shown, the Rayfan rays for each field of view are as follows: Figure 4 As shown, spherical aberration, field curvature, and distortion during close-range focusing are as follows: Figure 3 As shown, the Rayfan rays for each field of view are as follows: Figure 5 As shown.

[0028] The specific structure of the optical system in the large image field miniaturized wide-angle lens described in Embodiment 1 is shown in Table 1 below. In the table, RDY is the radius of curvature of each surface in mm; THI is the spacing and thickness of each lens element in mm; Nd is the refractive index of each glass element along the d-line; Vd is the Abbe number of the glass; the focal distance of the entire optical system is 16.9; and the aperture coefficient (Fno) is 2.86.

[0029] Table 1 object side of lens L11 39.50 5.64 2.05 26.94 Image side of lens L11 16.99 5.76 object side of lens L12 33.75 3.4 1.59 61.24 Image side of lens L12 14.64 6.47 object side of lens L13 -822.13 1.80 1.55 75.49 Image side of lens L13 18.03 2.14 object side of lens L14 31.58 6.06 1.73 32.23 Image side of lens L14 -82.00 7.08 The object side of the focusing lens LF -26.13 1.80 1.55 75.49 Image side view of the focusing lens LF 207.58 0.30 object side of lens L22 45.46 7.20 1.81 40.97 Image side of lens L22 -30.76 1.50 Aperture plane infinity 1.50 object side of lens L31 32.54 1.80 2.05 26.94 Image-side surface of lens L31 and object-side surface of lens L32 12.99 5.27 1.75 25.04 Image side of lens L32 -52.50 0.59 object side of lens L33 -35.36 1.80 1.95 32.31 Image-side surface of lens L33 and object-side surface of lens L34 23.58 5.82 1.59 68.62 Image side of lens L34 -23.73 0.30 Object side of lens L35 38.11 7.27 1.55 75.49 Image side of lens L35 -20.69 0.30 object side of lens L36 -47.57 1.80 1.95 32.31 Image-side surface of lens L36 and object-side surface of lens L37 21.01 9.64 1.55 75.49 Image-side surface of lens L37 and object-side surface of lens L38 -18.58 1.80 1.77 29.73 Image side of lens L38 -46.37 1.88 Object side of lens L39 -14.63 3.00 1.81 40.97 Image side of lens L39 -16.23 6.23 object side of lens L310 -30.90 5.34 1.87 20.01 Image side of lens L310 -24.16 20.00 Protect the object side of the glass lens infinity 2.0 1.5168 64.16 Image side of the protective glass lens infinity 1.0 In this embodiment 1, lenses L12, L22, and L33 are aspherical lenses, and their parameters are shown in Table 2 below. In the table, r is the radial coordinate starting from the optical axis; K is the conic coefficient of the aspherical surface; α2 is the 4th-order coefficient of the aspherical surface; α3 is the 6th-order coefficient of the aspherical surface; α4 is the 8th-order coefficient of the aspherical surface; α5 is the 10th-order coefficient of the aspherical surface; α6 is the 12th-order coefficient of the aspherical surface; and α7 is the 14th-order coefficient of the aspherical surface.

[0030] Table 2 object side of lens L12 0 4.7685e-05 -2.7253e-07 9.0155e-10 -1.4747e-12 8.4449e-16 Image side of lens L12 -1.023 5.2205e-05 -4.0556e-07 3.0869e-10 5.8396e-12 -3.1092e-14 object side of lens L22 0 8.9943e-06 1.6053e-08 5.4391e-09 -9.1651e-11 9.5607e-13 -3.6967e-15 Image side of lens L22 0 1.8148e-05 4.7750e-08 3.3004e-09 -4.4742e-11 4.7253e-13 -1.3528e-15 object side of lens L33 0 8.0594e-05 4.4034e-07 -3.9528e-09 1.3325e-11 -1.1642e-14 3.2472e-16 Image side of lens L33 0 8.1216e-05 3.8245e-07 -3.0718e-09 9.0172e-12 -9.9449e-15 -2.7752e-17 Furthermore, starting from the intersection point of the aspherical surface and the optical axis, the offset Z in the optical axis direction is:

[0031] In the formula, C is the curvature of the reference sphere that is not aspherical.

[0032] When THI(8) and THI(10) are equal to different values, the corresponding imaging distances are shown in Table 3 below, which correspond to infinity and 250mm respectively.

[0033] Table 3 THI(8) 7.08 6.62 THI(10) 0.3 0.76

[0034] like Figure 6As shown, the miniaturized wide-angle lens with a large image field described in Embodiment 2 of this utility model comprises, from the object side to the image side, 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; the aperture stop is set between the second lens group G2 and the third lens group G3; the first lens group G1 is composed of lenses L11 to L14 arranged sequentially from the object side to the image side, wherein lenses L11 and L12 constitute the first sub-lens group G11, and lenses L13 and L14 constitute the second sub-lens group G12; the second lens group G2 is composed of a focusing lens (LF lens) and lens L22 arranged sequentially from the object side to the image side; and the third lens group G3 is composed of lenses L31 to L311 arranged sequentially from the object side to the image side.

[0035] In the lens described in Embodiment 2, when an object moves from infinity to near, the focusing lens (LF lens) in the second lens group G2 moves to achieve focus. Testing showed that the spherical aberration, field curvature, and distortion of the lens described in Embodiment 2 when focusing at infinity are as follows: Figure 7 As shown, the Rayfan rays for each field of view are as follows: Figure 9 As shown, spherical aberration, field curvature, and distortion during close-range focusing are as follows: Figure 8 As shown, the Rayfan rays for each field of view are as follows: Figure 10 As shown The specific structure of the optical system in the large image field miniaturized wide-angle lens described in Embodiment 2 is shown in Table 4 below. In the table, RDY is the radius of curvature of each surface in mm; THI is the spacing and thickness of each lens element in mm; Nd is the refractive index of each glass element along the d-line; Vd is the Abbe number of the glass; the focal distance of the entire optical system is 16.9; and the aperture coefficient (Fno) is 2.86.

[0036] Table 4 object side of lens L11 41.22 2.3 1.92 20.88 Image side of lens L11 17.57 5.76 object side of lens L12 33.75 3.4 1.59 61.28 Image side of lens L12 14.63 7.23 object side of lens L13 -187.92 2.0 1.55 75.50 Image side of lens L13 21.68 1.05 object side of lens L14 26.72 5.3 1.77 29.74 Image side of lens L14 -3009.03 8.35 The object side of the focusing lens LF -23.77 1.9 1.59 68.62 Image side view of the focusing lens LF -278.37 0.30 object side of lens L22 29.46 4.1 1.65 33.84 Image side of lens L22 -41.71 1.50 Aperture plane infinity 1.5 object side of lens L31 26.49 1.8 1.95 29.83 Image-side surface of lens L31 and object-side surface of lens L32 12.08 4.8 1.75 25.05 Image side of lens L32 -77.80 1.5 object side of lens L33 -22.04 1.6 1.95 29.83 Image-side surface of lens L33 and object-side surface of lens L34 27.58 5.1 1.57 56.04 Image side of lens L34 -34.43 0.30 Object side of lens L35 52.65 7.1 1.55 71.76 Image side of lens L35 -23.05 0.30 object side of lens L36 -1145.52 6.15 1.50 81.56 Image-side surface of lens L36 and object-side surface of lens L37 -18.92 2.0 1.85 25.15 Image side of lens L37 -2142.85 0.30 object side of lens L38 39.78 8.5 1.59 67.02 Image side of lens L38 -38.62 1.41 Object side of lens L39 -71.05 2.00 1.85 25.15 Image side of lens L39 294.24 6.2 Object-side surface of lens L310 -15.86 3.0 1.95 29.83 Image side of lens L310 -20.04 1.1 object side of lens L311 -59.54 5.65 1.87 20.02 Image side of lens L311 -31.19 20.0 Protect the object side of the glass lens infinity 2.0 1.5168 64.16 Image side of the protective glass lens infinity 1.0 In this embodiment 2, lenses L12, L38, and L310 are aspherical lenses, and their parameters are shown in Table 5 below. In the table, r is the radial coordinate starting from the optical axis; K is the conic coefficient of the aspherical surface; α2 is the 4th-order coefficient of the aspherical surface; α3 is the 6th-order coefficient of the aspherical surface; α4 is the 8th-order coefficient of the aspherical surface; α5 is the 10th-order coefficient of the aspherical surface; and α6 is the 12th-order coefficient of the aspherical surface.

[0037] Table 5 object side of lens L12 0 4.7685e-05 -2.7253e-07 9.0155e-10 -1.4747e-12 8.4449e-16 Image side of lens L12 -1.023 5.2205e-05 -4.0556e-07 3.0869e-10 5.8396e-12 -3.1092e-14 object side of lens L38 0 -9.5301e-07 -2.1715e-08 2.2898e-10 -2.3065e-12 6.5752e-15 Image side of lens L38 0 6.7772e-07 -1.5096e-08 -4.6147e-10 1.0602e-12 1.8600e-15 Object-side surface of lens L310 0 1.0194e-05 7.1017e-07 -4.4605e-09 1.3265e-11 -4.7882e-15 Image side of lens L310 0 2.3543e-05 4.7373e-07 -2.4437e-09 7.0496e-12 -7.9548e-15 Furthermore, starting from the intersection point of the aspherical surface and the optical axis, the offset Z in the optical axis direction is:

[0038] In the formula, C is the curvature of the reference sphere that is not aspherical.

[0039] When THI(8) and THI(10) are equal to different values, the corresponding imaging distances are shown in Table 6 below, which correspond to infinity and 250mm respectively.

[0040] Table 6 THI(8) 8.35 7.15 THI(10) 0.3 1.5

[0041] like Figure 11 As shown, the miniaturized wide-angle lens with a large image field described in Embodiment 3 of this utility model comprises, from the object side to the image side, 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; the aperture stop is set between the second lens group G2 and the third lens group G3; the first lens group G1 is composed of lenses L11 to L14 arranged sequentially from the object side to the image side, wherein lenses L11 and L12 constitute the first sub-lens group G11, and lenses L13 and L14 constitute the second sub-lens group G12; the second lens group G2 is composed of a focusing lens (LF lens) and lens L22 arranged sequentially from the object side to the image side; and the third lens group G3 is composed of lenses L31 to L311 arranged sequentially from the object side to the image side.

[0042] In this embodiment 3, when the lens is used, as the object moves from infinity to near, the LF lens in the second lens group G2 moves to achieve focus. Testing showed that the spherical aberration, field curvature, and distortion of the large-aperture miniaturized wide-angle lens described in this embodiment 3 when focusing at infinity are as follows: Figure 12 As shown, the Rayfan rays for each field of view are as follows: Figure 14 As shown, spherical aberration, field curvature, and distortion during close-range focusing are as follows: Figure 13 As shown, the Rayfan rays for each field of view are as follows: Figure 15 As shown.

[0043] The specific structure of the optical system in the large-aperture miniaturized wide-angle lens described in Embodiment 3 is shown in Table 7 below. In the table, RDY is the radius of curvature of each surface in mm; THI is the spacing and thickness of each lens element in mm; Nd is the refractive index of each glass element along the d-line; Vd is the Abbe number of the glass; the focal distance of the entire optical system is 16.9; and the aperture coefficient (Fno) is 2.86.

[0044] Table 7 object side of lens L11 39.53 2.3 1.92 20.88 Image side of lens L11 17.47 5.89 object side of lens L12 33.76 3.4 1.59 61.28 Image side of lens L12 14.64 7.24 object side of lens L13 -162.89 2 1.55 75.50 Image side of lens L13 22.38 1.27 object side of lens L14 30.45 5.3 1.77 29.74 Image side of lens L14 -254.28 7.94 The object side of the focusing lens LF -23.73 1.9 1.59 68.62 Image side view of the focusing lens LF -173.95 0.30 object side of lens L22 28.11 4.1 1.65 33.84 Image side of lens L22 -45.60 1.5 Aperture plane infinity 1.5 object side of lens L31 32.23 2.7 1.95 29.83 Image-side surface of lens L31 and object-side surface of lens L32 12.41 5.2 1.75 25.05 Image side of lens L32 -57.06 1.5 object side of lens L33 -19.91 1.8 1.95 29.83 Image-side surface of lens L33 and object-side surface of lens L34 34.24 4.55 1.57 56.04 Image side of lens L34 -27.34 0.30 Object side of lens L35 53.83 6.2 1.55 71.76 Image side of lens L35 -24.30 0.30 object side of lens L36 -182.15 6.15 1.50 81.56 Image-side surface of lens L36 and object-side surface of lens L37 -18.32 2.0 1.85 25.15 Image side of lens L37 -101.98 0.30 object side of lens L38 54.77 8.5 1.59 68.62 Image side of lens L38 -30.15 1.41 Object side of lens L39 -60.16 2.0 1.85 25.15 Image side of lens L39 121.79 6.2 Object-side surface of lens L310 -18.33 3.0 1.95 29.83 Image side of lens L310 -23.44 1.1 object side of lens L311 -71.29 5.65 1.87 20.02 Image side of lens L311 -33.03 20 Protect the object side of the glass lens infinity 2.0 1.5168 64.16 Image side of the protective glass lens infinity 1.0 In this embodiment 3, lenses L12 and L310 are aspherical lenses, and their parameters are shown in Table 8 below. In the table, r is the radial coordinate starting from the optical axis; K is the conic coefficient of the aspherical surface; α2 is the 4th-order coefficient of the aspherical surface; α3 is the 6th-order coefficient of the aspherical surface; α4 is the 8th-order coefficient of the aspherical surface; α5 is the 10th-order coefficient of the aspherical surface; and α6 is the 12th-order coefficient of the aspherical surface.

[0045] Table 8 object side of lens L12 0 4.7685e-05 -2.7253e-07 9.0155e-10 -1.4747e-12 8.4449e-16 Image side of lens L12 -1.023 5.2205e-05 -4.0556e-07 3.0869e-10 5.8396e-12 -3.1092e-14 Object-side surface of lens L310 0 -1.7340e-05 3.6806e-07 -1.7797e-10 -2.8912e-12 5.4686e-15 Image side of lens L310 0 5.8700e-06 2.5227e-07 -9.6194e-11 -1.7417e-12 2.8425e-15 Furthermore, starting from the intersection point of the aspherical surface and the optical axis, the offset Z in the optical axis direction is:

[0046] In the formula, C is the curvature of the reference sphere that is not aspherical.

[0047] When THI(8) and THI(10) are equal to different values, the corresponding imaging distances are shown in Table 9 below, which correspond to infinity and 250mm respectively.

[0048] Table 9 THI(8) 7.94 7.15 THI(10) 0.3 1.09 The specific situations in which embodiments 1 to 3 of this utility model satisfy the above conditions (1) to (7) are shown in Table 10 below.

[0049] Table 10 Condition (1): 1.5 ≤ EFL_ASP / EFL_G1 ≤ 4.0 2.17 2.38 2.33 Condition (2): 2.2 ≤ L / L1_S ≤ 3.5 2.58 2.93 2.94 Condition (3): -2.6 ≤ |EFL_G3 / EFL_G1| ≤ -1.8 -2.3 -2.17 -2.12 Condition (4): -3.3 ≤ |EFL_G2 / EFL_G1| ≤ -1.8 -2.06 -3.12 -2.88 Conditional expression (5): -3.1≤EFL_LF / EFL≤-2.1 -2.48 -2.59 -2.74 Condition (6): -42≤EFL_G12 / EFL_G11≤-14 -17.09 -30.7 -35.0 Condition (7): 0.40 ≤ |y'Max / EFL_G3| ≤ 0.80 0.55 0.64 0.64 The above description is the preferred embodiment of this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this utility model, and these improvements and modifications are also considered to be within the protection scope of this utility model.

Claims

1. A miniaturized wide-angle lens with a large image field, characterized in that, From the object side to the image plane, the lens group consists of 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; wherein... The first lens group G1 consists of a first sub-lens group G11 with negative refractive power and a second sub-lens group G12 with positive refractive power; the second lens group G2 includes an LF lens, which serves as a focusing lens for focusing at both near and far distances; an aperture STOP is provided between the second lens group G2 and the third lens group G3. Both the first lens group G1 and the third lens group G3 contain at least one aspherical lens, wherein the focal length of the aspherical lens in the first lens group G1 satisfies the following condition: 1.5 ≤ EFL_ASP / EFL_G1 ≤ 4.0 In the formula, EFL_ASP is the focal length of the aspherical lens in the first lens group G1; EFL_G1 is the focal length of the first lens group G1.

2. The large image field miniaturized wide-angle lens according to claim 1, characterized in that, The position of the aperture STOP satisfies the following condition: 2.2≤L / L1_S≤3.5 In the formula, L1_S is the distance from the object side to the aperture stop; L is the distance from the first surface to the image plane from the object side.

3. The large image field miniaturized wide-angle lens according to claim 1, characterized in that, The focal lengths of the first lens group G1, the second lens group G2, and the third lens group G3 satisfy the following condition: -2.6 ≤ |EFL_G3 / EFL_G1| ≤ -1.8 -3.3 ≤ |EFL_G2 / EFL_G1| ≤ -1.8 In the formula, EFL_G1 is the focal length of the first lens group G1, EFL_G2 is the focal length of the second lens group G2, and EFL_G3 is the focal length of the third lens group G3.

4. The large image field miniaturized wide-angle lens according to claim 1, characterized in that, The LF lens in the second lens group G2 satisfies the following condition: -3.1 ≤ EFL_LF / EFL ≤ -2.1 In the formula, EFL is the focal length of the entire optical system at infinity; EFL_LF is the focal length of the LF lens in the second lens group G2.

5. The large image field miniaturized wide-angle lens according to claim 1, 2, 3, or 4, characterized in that, The first sub-lens group G11 and the second sub-lens group G12 in the first lens group G1 satisfy the following condition: -42≤EFL_G12 / EFL_G11≤-14 In the formula, EFL_G11 is the focal length of the first sub-lens group G11, and EFL_G12 is the focal length of the second sub-lens group G12.

6. The large image field miniaturized wide-angle lens according to claim 5, characterized in that, The third lens group G3 and the maximum image height at infinity satisfy the following condition: 0.40≤│y'Max / EFL_G3│≤ 0.80 In the formula, EFL_G3 is the focal length of the third lens group G3, y'Max is the maximum paraxial image height at infinity, y'Max = EFL × tanω, and ω is the half-angle of the entire optical system at infinity.

7. The large image field miniaturized wide-angle lens according to claim 1, 2, 3, 4, or 6, characterized in that, The third lens group G3 consists of 10 lenses L31 to L310 arranged sequentially from the object side to the image plane, including at least two sets of cemented doublet lenses and one set of cemented triplet lenses; or, the third lens group G3 consists of 11 lenses L31 to L311 arranged sequentially from the object side to the image plane, including at least three sets of cemented doublet lenses.

8. The large image field miniaturized wide-angle lens according to claim 7, characterized in that, When the third lens group G3 consists of 10 lenses, lenses L31 and L32, and lenses L33 and L34 respectively constitute cemented doublet lenses, and lenses L36, L37, and L38 constitute cemented triplets. When the third lens group G3 consists of 11 lenses, lenses L31 and L32, lenses L33 and L34, and lenses L36 and L37 respectively constitute cemented doublet lenses.

9. The large image field miniaturized wide-angle lens according to claim 1, 2, 3, 4, 6, or 8, characterized in that, The first lens group G1 is composed of lenses L11 to L14 arranged sequentially from the object side toward the image plane, wherein lens L11 and lens L12 constitute the first sub-lens group G11, and lens L13 and lens L14 constitute the second sub-lens group G12, and lens L12 is an aspherical lens.

10. The large image field miniaturized wide-angle lens according to claim 1, 2, 3, 4, 6, or 8, characterized in that, The second lens group G2 consists of an LF lens and a lens L22 arranged sequentially from the object side toward the image plane.

Images