Large-aperture camera lens with focal length of 23 mm

Abstract

The invention discloses a 23mm-focal-length large-aperture camera lens. The 23mm-focal-length large-aperture camera lens sequentially comprises a first lens group, an iris diaphragm, a second lens group and a third lens group from an object side to an imaging surface, the first lens group serves as a fixed group, has positive focal power, and comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens; the second lens group is used as a focusing group, has positive focal power, and comprises a seventh lens, an eighth lens and a ninth lens; the third lens group serves as a fixed group, has negative focal power and comprises a tenth lens, an eleventh lens and a twelfth lens; the aspheric lens is used for optimizing aberration, the cost and appearance advantages are achieved, meanwhile, the high-performance expression of the F1.4 maximum aperture is achieved, the imaging is excellent at infinity and close-up distance, the distortion is smaller than 2%, the discomfort of video shooting is greatly reduced, and the shooting experience is improved.

Description

Technical Field

[0001] The invention relates to the technical field of camera lenses, in particular to a 23mm focal length large aperture camera lens. Background Art

[0002] Due to the popularity of short videos on social platforms, more and more netizens share and communicate by shooting daily vlogs. For these people, having a small and lightweight automatic micro-single camera lens can achieve twice the result with half the effort. In the early days, the micro-single lenses on the market mainly focused on the quality of taking pictures, and matched the needs of customers through large apertures, small distortions, blurring effects, etc. However, many early products did not take into account the uncomfortable breathing jitters that occurred during video shooting. If a lens that can greatly reduce breathing jitters when shooting videos in addition to excellent resolution, small distortion, large aperture, light and compact can be developed, it will definitely be favored by professionals in the market and have great product competitiveness. Therefore, the present invention designs a 23mm focal length large aperture camera lens to improve the above problems. Summary of the invention

[0003] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a 23mm focal length large aperture camera lens, which uses an aspherical lens to optimize aberrations, achieves high performance of a maximum aperture of F1.4 while achieving cost and appearance advantages, and has excellent imaging at infinity and close shooting distances, with a distortion of less than 2%, greatly reducing the discomfort of video shooting and improving the photography experience.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] A 23mm focal length large aperture camera lens, comprising a first lens group, a variable aperture, a second lens group and a third lens group in order from the object side to the imaging surface;

[0006] The first lens group is a fixed group with positive optical power, and includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens;

[0007] The second lens group is a focusing group with positive optical power, and includes a seventh lens, an eighth lens and a ninth lens;

[0008] The third lens group is a fixed group with negative optical power, and includes a tenth lens, an eleventh lens and a twelfth lens;

[0009] The first lens and the third lens are negative meniscus lenses curved toward the image plane and meet the following conditions:

[0010] 0.96 <F1 / F3<1.89

[0011] 0.92 <G1 R2 / G3R2<1.87

[0012] Wherein, F1 is the focal length of the first lens, F3 is the focal length of the third lens, G1 R2 is the curvature radius of a side of the first lens close to the imaging surface, and G3R2 is the curvature radius of a side of the third lens close to the imaging surface.

[0013] Preferably, the second lens is a positive meniscus lens curved toward the imaging surface, satisfying the following conditions:

[0014] Nd2>1.84

[0015] Wherein, ND2 is the refractive index of the second lens.

[0016] Preferably, the focal length of the first lens group satisfies the following conditions:

[0017] 0.92 <FG1 / f<1.85

[0018] Wherein, FG1 is the focal length of the first lens group, and f is the focal length of the camera lens optical system. Preferably, the second lens in the second lens group satisfies the following conditions:

[0019] Vd8>70.4

[0020] Wherein, Vd8 is the Abbe number of the second lens in the second lens group.

[0021] Preferably, the third lens in the second lens group meets the following conditions:

[0022] Nd9>1.84

[0023] Wherein, Nd9 is the refractive index of the third lens in the second lens group.

[0024] Preferably, the focal length of the second lens group satisfies the following conditions:

[0025] 1.48 <FG2 / f<3.70

[0026] Wherein, FG2 is the focal length of the second lens group, and f is the focal length of the camera lens optical system. Preferably, the third lens group contains a biconvex air spacer, which satisfies the following conditions:

[0027] -0.5<(A10R2+A10R1) / (A10R2-A10R1)<1.5

[0028] Among them, A10R1 is the curvature radius of the side surface of the biconvex air space in the third lens group close to the object side, and A10R2 is the curvature radius of the side surface of the biconvex air space in the third lens group close to the imaging surface.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] The present invention uses aspheric lenses to optimize aberrations, has a short and lightweight structure, and achieves high performance of a maximum aperture of F1.4 while achieving cost and appearance advantages. It has excellent imaging at infinity and close shooting distances, and distortion is less than 2%; the system is divided into three groups of lens groups to simplify the structure and reduce tolerance accommodation; a mobile group that meets the low breathing effect is selected by calculation, and the light incident position and length of the mobile group and the positive and negative optical power ratio are adjusted, so that the picture angle change of the system when switching between long and short shooting tends to be smooth, which greatly reduces the discomfort of video shooting and improves the photography experience; the size and weight of the mobile lens are small, the motor load is small, and the focusing efficiency is effectively guaranteed. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a schematic diagram of the lens structure of a 23mm focal length large aperture camera lens;

[0032] Figure 2 The spherical aberration curve, field curvature curve and distortion curve of the 23mm focal length and large aperture camera lens;

[0033] Figure 3 It is a schematic diagram of the lens structure of another embodiment of a 23mm focal length large aperture camera lens;

[0034] Figure 4 The spherical aberration curve, field curvature curve and distortion curve of another embodiment of a 23mm focal length large aperture camera lens.

[0035] In the figure: G1, first lens group; G2, second lens group; G3, third lens group; 1, first lens; 2, second lens; 3, third lens; 4, fourth lens; 5, fifth lens; 6, sixth lens; 7, seventh lens; 8, eighth lens; 9, ninth lens; 10, tenth lens; 11, eleventh lens; 12, twelfth lens; 13, thirteenth lens. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0037] Embodiment 1:

[0038] See also Figure 1, this embodiment provides a 23mm focal length large aperture camera lens, which includes a first lens group G1, a variable aperture, a second lens group G2 and a third lens group G3 in sequence from the object side to the imaging surface;

[0039] The first lens group G1 is a fixed group with positive optical power, and includes a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a fifth lens 5 and a sixth lens 6;

[0040] The second lens group G2 is a focusing group (moving group) with positive optical power, and includes a seventh lens 7, an eighth lens 8 and a ninth lens 9;

[0041] The third lens group G3 is a fixed group with negative optical power, including a tenth lens 10, an eleventh lens 11 and a twelfth lens 12, wherein the number of lenses in the first lens group G1, the second lens group G2 and the third lens group G3 is designed according to design and use requirements, and increasing or decreasing the number of lenses falls within the protection scope of the present invention;

[0042] The first lens 1 and the third lens 3 are negative meniscus lenses curved toward the image plane and meet the following conditions:

[0043] 0.96 <F1 / F3<1.89

[0044] 0.92 <G1 R2 / G3R2<1.87

[0045] Wherein, F1 is the focal length of the first lens 1, F3 is the focal length of the third lens 3, G1 R2 is the curvature radius of a side surface of the first lens 1 close to the imaging surface, and G3R2 is the curvature radius of a side surface of the third lens 3 close to the imaging surface.

[0046] In this embodiment, the second lens 2 is a positive meniscus lens curved toward the imaging surface, satisfying the following conditions:

[0047] Nd2>1.84

[0048] Wherein, ND2 is the refractive index of the second lens 2 .

[0049] In this embodiment, the focal length of the first lens group G1 satisfies the following conditions:

[0050] 0.92 <FG1 / f<1.85

[0051] Wherein, FG1 is the focal length of the first lens group G1, and f is the focal length of the camera lens optical system.

[0052] In this embodiment, the second lens (i.e., the eighth lens 8) in the second lens group G2 satisfies the following conditions:

[0053] Vd8>70.4

[0054] Here, Vd8 is the Abbe number of the second lens (the eighth lens 8) in the second lens group G2.

[0055] In this embodiment, the third lens (i.e., the ninth lens 9) in the second lens group G2 satisfies the following conditions:

[0056] Nd9>1.84

[0057] Wherein, Nd9 is the refractive index of the third lens (ninth lens 9) in the second lens group G2. In this embodiment, the focal length of the second lens group G2 satisfies the following conditions:

[0058] 1.48 <FG2 / f<3.70

[0059] Among them, FG2 is the focal length of the second lens group G2, and f is the focal length of the camera lens optical system.

[0060] In this embodiment, the third lens group G3 contains a biconvex air spacer, which satisfies the following conditions:

[0061] -0.5<(A10R2+A10R1) / (A10R2-A10R1)<1.5

[0062] Wherein, A10R1 is the curvature radius of a side surface of the biconvex air space in the third lens group G3 close to the object side, and A10R2 is the curvature radius of a side surface of the biconvex air space in the third lens group G3 close to the imaging surface.

[0063] As a preferred embodiment of the technical solution of this embodiment, the parameters of the camera lens embodiment are shown in Table 1 below, wherein the aspheric coefficients of the aspheric lens are shown in Table 2 below, and the surface number column shows the surface number when the surface close to the object side is set as the first surface and the surface number is increased one by one toward the imaging surface side, and the shape parameters of each lens are:

[0064] Table 1

[0065]

[0066] Table 2

[0067]

[0068]

[0069] As a preferred technical solution, the positions of the focus compensation group (moving group) of the camera lens in different focus states in this embodiment are shown in Table 3 below, which are the values ​​of the two states of D1 and D2 in Table 1:

[0070] Table 3

[0071] Conjugate distance Infinity Closest (0.25m) D1 10.48mm 5.28mm D2 0.8mm 6mm

[0072] As a preferred technical solution, the physical parameters of the camera lens in this embodiment are shown in Table 4 below:

[0073] Table 4

[0074] Focal length f 23.01mm Relative aperture FNO. 1.45 Field of viewω 66.2° Total optical length 98mm

[0075] Figure 2 3 is a spherical aberration curve diagram of the camera lens in this embodiment, a field curvature curve diagram of the camera lens, and a distortion curve diagram of the camera lens. It can be seen that the camera lens in this embodiment has a good imaging effect.

[0076] In this embodiment, through the limitation of the above conditional formula, aspherical lenses are used to optimize aberrations, and the structure is short and lightweight. While achieving cost and appearance advantages, high performance of F1.4 maximum aperture is achieved, and imaging is excellent at infinity and close shooting distances, with distortion less than 2%; the system is divided into 3 groups of lens groups to simplify the structure and reduce tolerance accommodation; the mobile group that meets the low breathing effect is selected by calculation, and the light incident position and length and the positive and negative optical power ratio of the mobile group are adjusted, so that the picture angle change of the system when switching between long and short shooting tends to be smooth, which greatly reduces the discomfort of video shooting and improves the photography experience; the size and weight of the mobile lens are small, the motor load is small, and the focusing efficiency is effectively guaranteed.

[0077] Embodiment 2:

[0078] See also Figure 3 , this embodiment provides a 23mm focal length large aperture camera lens, which includes a first lens group G1, a variable aperture, a second lens group G2 and a third lens group G3 in sequence from the object side to the imaging surface;

[0079] The first lens group G1 is a fixed group with positive optical power, and includes a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a fifth lens 5, a sixth lens 6 and a seventh lens 7;

[0080] The second lens group G2 is a focusing group (moving group) with positive optical power, and includes an eighth lens 8, a ninth lens 9 and a tenth lens 10;

[0081] The third lens group G3 is a fixed group with negative optical power, and includes an eleventh lens 11, a twelfth lens 12 and a thirteenth lens 13. The number of lenses in the first lens group G1, the second lens group G2 and the third lens group G3 is designed according to design and use requirements, and increasing or decreasing the number of lenses falls within the protection scope of the present invention.

[0082] The first lens 1 and the third lens 3 are negative meniscus lenses curved toward the image plane and meet the following conditions:

[0083] 0.96 <F1 / F3<1.89

[0084] 0.92 <G1 R2 / G3R2<1.87

[0085] Wherein, F1 is the focal length of the first lens 1, F3 is the focal length of the third lens 3, G1 R2 is the curvature radius of a side surface of the first lens 1 close to the imaging surface, and G3R2 is the curvature radius of a side surface of the third lens 3 close to the imaging surface.

[0086] In this embodiment, the second lens 2 is a positive meniscus lens curved toward the imaging surface, satisfying the following conditions:

[0087] Nd2>1.84

[0088] Wherein, ND2 is the refractive index of the second lens 2 .

[0089] In this embodiment, the focal length of the first lens group G1 satisfies the following conditions:

[0090] 0.92 <FG1 / f<1.85

[0091] Wherein, FG1 is the focal length of the first lens group G1, and f is the focal length of the camera lens optical system.

[0092] In this embodiment, the second lens (i.e., the ninth lens 9) in the second lens group G2 satisfies the following conditions:

[0093] Vd8>70.4

[0094] Here, Vd8 is the Abbe number of the second lens (ninth lens 9) in the second lens group G2.

[0095] In this embodiment, the third lens (i.e., the tenth lens 10) in the second lens group G2 satisfies the following conditions:

[0096] Nd9>1.84

[0097] Wherein, Nd9 is the refractive index of the third lens (the tenth lens 10) in the second lens group G2. In this embodiment, the focal length of the second lens group G2 satisfies the following conditions:

[0098] 1.48 <FG2 / f<3.70

[0099] Among them, FG2 is the focal length of the second lens group G2, and f is the focal length of the camera lens optical system.

[0100] In this embodiment, the third lens group G3 contains a biconvex air spacer, which satisfies the following conditions:

[0101] -0.5<(A10R2+A10R1) / (A10R2-A10R1)<1.5

[0102] Wherein, A10R1 is the curvature radius of a side surface of the biconvex air space in the third lens group G3 close to the object side, and A10R2 is the curvature radius of a side surface of the biconvex air space in the third lens group G3 close to the imaging surface.

[0103] As a preferred embodiment of the technical solution of this embodiment, the parameters of the camera lens embodiment are shown in Table 5 below, wherein the aspheric coefficients of the aspheric lens are shown in Table 6 below, and the surface number column shows the surface number when the surface close to the object side is set as the first surface and the surface number is increased one by one toward the imaging surface side, and the shape parameters of each lens are:

[0104] Table 5

[0105]

[0106] Table 6

[0107] Surface serial number 24 25 k -3.6048 -1.1307 A4 -9.293e-06 -6.787e-05 A6 2.823e-07 2.277e-07 A8 1.844e-09 2.138e-09 A10 -3.486e-11 -2.906e-11 A12 1.684e-13 1.256e-13

[0108] As a preferred technical solution, the positions of the focus compensation group (moving group) of the camera lens in different focus states in this embodiment are shown in Table 3 below, which are the values ​​of the two states of D1 and D2 in Table 1:

[0109] Table 7

[0110] Conjugate distance Infinity Closest (0.25m) D1 8.98mm 5.08mm D2 1.3mm 5.2mm

[0111] As a preferred technical solution, the physical parameters of the camera lens in this embodiment are shown in Table 4 below:

[0112] Table 8

[0113] Focal length f 22.99mm Relative aperture FNO. 1.46 Field of viewω 67.5° Total optical length 97mm

[0114] Figure 4 3 is a spherical aberration curve diagram of the camera lens in this embodiment, a field curvature curve diagram of the camera lens, and a distortion curve diagram of the camera lens. It can be seen that the camera lens in this embodiment has a good imaging effect.

[0115] The above embodiments are preferred implementation schemes of the present invention. In addition, the present invention may also be implemented in other ways. Any obvious replacement without departing from the concept of the present technical solution is within the protection scope of the present invention.

Claims

1. A 23mm focal length large aperture camera lens, characterized in that: From the object side to the imaging surface, it includes a first lens group (G1), a variable aperture, a second lens group (G2) and a third lens group (G3); The first lens group (G1) is a fixed group with positive optical power, and includes a first lens (1), a second lens (2), a third lens (3), a fourth lens (4), a fifth lens (5) and a sixth lens (6); The second lens group (G2) is a focusing group with positive optical power, and includes a seventh lens (7), an eighth lens (8) and a ninth lens (9); The third lens group (G3) is a fixed group with negative optical power, and includes a tenth lens (10), an eleventh lens (11) and a twelfth lens (12); The first lens (1) and the third lens (3) are negative meniscus lenses curved toward the image plane and meet the following conditions: 0.96 <F1 / F3<1.89 0.92 <G1R2 / G3R2<1.87 Wherein, F1 is the focal length of the first lens (1), F3 is the focal length of the third lens (3), G1R2 is the curvature radius of a side surface of the first lens (1) close to the imaging surface, and G3R2 is the curvature radius of a side surface of the third lens (3) close to the imaging surface.

2. The 23mm focal length large aperture camera lens according to claim 1, characterized in that: The second lens (2) is a positive meniscus lens curved toward the imaging surface and meets the following conditions: Nd2>1.84 Wherein, ND2 is the refractive index of the second lens (2).

3. The 23mm focal length large aperture camera lens according to claim 1, characterized in that: The focal length of the first lens group (G1) satisfies the following conditions: 0.92 <FG1 / f<1.85 Among them, FG1 is the focal length of the first lens group (G1), and f is the focal length of the camera lens optical system.

4. The 23mm focal length large aperture camera lens according to claim 1, characterized in that: The second lens in the second lens group (G2) satisfies the following conditions: Vd8>70.4 Wherein, Vd8 is the Abbe number of the second lens in the second lens group (G2).

5. The 23mm focal length large aperture camera lens according to claim 1, characterized in that: The third lens in the second lens group (G2) satisfies the following conditions: Nd9>1.84 Wherein, Nd9 is the refractive index of the third lens in the second lens group (G2).

6. The 23mm focal length large aperture camera lens according to claim 1, characterized in that: The focal length of the second lens group (G2) satisfies the following conditions: 1.48 <FG2 / f<3.70 Among them, FG2 is the focal length of the second lens group (G2), and f is the focal length of the camera lens optical system.

7. The 23 mm focal length large aperture camera lens according to claim 1, characterized in that: The third lens group (G3) contains a biconvex air spacer, which satisfies the following conditions: -0.5<(A10R2+A10R1) / (A10R2-A10R1)<1.5 Wherein, A10R1 is the curvature radius of a side surface of the biconvex air space in the third lens group (G3) close to the object side, and A10R2 is the curvature radius of a side surface of the biconvex air space in the third lens group (G3) close to the imaging surface.

Images