CN218446180U - Large-aperture lens - Google Patents

Abstract

The utility model relates to a big light ring camera lens, include: a first lens (L1), a second lens (L2), a third lens (L3), a fourth lens (L4), a fifth lens (L5), a sixth lens (L6), a seventh lens (L7), an eighth lens (L8), a ninth lens (L9), a tenth lens (L10), an eleventh lens (L11), and a twelfth lens (L12) arranged in this order from the object side to the image side along the optical axis, wherein the focal powers of the first lens (L1) and the second lens (L2) are negative, and the focal powers of the third lens (L3), the seventh lens (L7), and the eleventh lens (L11) are positive; the image-side surface of the first lens (L1) is concave, the third lens (L3) is a biconvex lens, the object-side surfaces of the seventh lens (L7) and the eleventh lens (L11) are convex, and the image-side surface of the twelfth lens (L12) is convex. The maximum aperture of the lens is F0.7, 5M pixels are considered, and the arbitrary switching of F0.7/F1.6 two-gear apertures is realized.

Description

Large-aperture lens

Technical Field

The utility model relates to an imaging optical system technical field especially relates to a big light ring camera lens.

Background

With the rapid development of science and technology, the requirements on the optical lens are higher and higher. The maximum aperture of the existing lens on the market can reach about F1.0, and the imaging effect of the lens can meet the common dim light environment. But for scenes with extremely weak environmental brightness, the light transmission capability of the scene is still unsatisfactory. In order to satisfy higher pixels and stronger low-light imaging effect, the research direction of the imaging lens with larger aperture and higher resolution becomes a new hot spot. The current light ring with few lenses can reach F0.8, but the size is huge, the total length of the lenses can reach more than 120mm, and the application occasions are generally infrared fields, and for security monitoring, the lenses do not have practical value.

SUMMERY OF THE UTILITY MODEL

The utility model aims to provide a big light ring camera lens with low costs, can normally work at-40- +80 ℃, can realize maximum light ring F0.7, compromise 5M pixel simultaneously to can realize that F0.7F 1.6 switches wantonly, satisfy the demand of different scenes.

To achieve the above object, the present invention provides a large aperture lens, including: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens, a tenth lens, an eleventh lens, and a twelfth lens which are arranged in this order from an object side to an image side along an optical axis,

the focal power of the first lens and the second lens is negative, and the focal power of the third lens, the seventh lens and the eleventh lens is positive;

the image side surface of the first lens is concave, the third lens is a biconvex lens, the object side surfaces of the seventh lens and the eleventh lens are convex, and the image side surface of the twelfth lens is convex.

According to an aspect of the present invention, the large aperture lens further includes a thirteenth lens located on the image side of the twelfth lens.

According to an aspect of the present invention, the thirteenth lens is a convex-concave lens in a direction from the object side to the image side along the optical axis.

According to an aspect of the present invention, the large aperture lens further includes a diaphragm, the diaphragm is located between the third lens and the fourth lens, between the fourth lens and the fifth lens or between the sixth lens and the seventh lens.

According to the utility model discloses an aspect, the diaphragm with central distance D1 between the adjacent lens in image side of diaphragm and with central distance D between two adjacent pieces of lens in diaphragm satisfies the relational expression: D1/D is more than or equal to 0 and less than or equal to 0.5.

According to an aspect of the present invention, the large aperture lens includes a double cemented lens group and a triple cemented lens group.

According to the utility model discloses an aspect, the focus Fa of two cemented lens group with the effective focal length F of big light ring camera lens satisfies the relational expression: the absolute Fa/F is more than or equal to 11 and less than or equal to 28.

According to an aspect of the utility model, the focal length Fb of three cemented lens group with the effective focal length F of big light ring camera lens satisfies the relational expression: the absolute value of Fb/F is more than or equal to 4 and less than or equal to 10.

According to the utility model discloses an aspect, the veneer is constituteed the difference Vd2 of the abbe's numerical value of two pieces of lenses of two cemented lens groups satisfies the relational expression: the Vd2 is less than or equal to 40 and is more than or equal to 10.

According to the utility model discloses an aspect, the veneer is constituteed the biggest numerical value of the abbe number of three pieces of lens of three veneer lens group and the difference Vd3 of minimum numerical value satisfy the relational expression: the Vd3 is less than or equal to 50 and is more than or equal to 15.

According to an aspect of the utility model, big light ring camera lens contains seven pieces of focal power at least and is positive lens and four pieces of focal power are negative lens.

According to the utility model discloses an aspect, big light ring camera lens contains five pieces of plastic aspheric surface lens at least.

According to an aspect of the present invention, the curvature radius R1 of the object side surface of the third lens element and the curvature radius R2 of the image side surface of the third lens element satisfy the relation: the ratio of (R1 + R2)/(R1-R2) is more than or equal to 0.1 and less than or equal to 0.6.

According to an aspect of the present invention, from the object side in the large aperture lens, the combined focal length FG1 of the lens front group composed of the first two lenses or the first three lenses and the effective focal length F of the large aperture lens satisfy the relation: FG1/F is less than or equal to-1 and is less than or equal to-5.

According to an aspect of the present invention, from the object side in the large aperture lens, the combined focal length FG2 of the lens rear group composed of the last two lenses or the last three lenses and the effective focal length F of the large aperture lens satisfy the relation: FG2/F is more than or equal to 2 and less than or equal to 9.

According to the utility model discloses an aspect, the optics total length TTL of big light ring camera lens with the entrance pupil diameter ENPD of big light ring camera lens satisfies the relational expression: TTL/ENPD is more than or equal to 7 and less than or equal to 10.

According to the utility model discloses an aspect, the high IH of half of the image of big light ring camera lens with the optics total length TTL of big light ring camera lens satisfies the relational expression: TTL/IH is not less than 11 and not more than 15.

According to the utility model discloses a scheme adopts the optics framework by twelve pieces of lenses or thirteen pieces of lenses, and the concave-convex different shapes, the face type and the material etc. of the positive and negative focal power, the object side and the image side of each lens of rational distribution can make this camera lens have super large light ring, high and the imaging quality performance such as excellence of resolution power, and maximum light ring FNO =0.7, and the resolution power reaches 5M pixel requirement simultaneously, guarantees to have high resolution ratio promptly under big light ring.

According to the utility model discloses a scheme, the mixed optimal design of plastic aspheric lens and glass spherical lens has overcome plastic aspheric lens because coefficient of expansion is big, causes the difficulty of focus drift easily under high low temperature environment, makes this camera lens can realize not virtual burnt at-40 ℃ -80 ℃ temperature range. In addition, the scheme of mixing the glass and plastic material lenses is successfully applied to the large-aperture lens with the imaging performance, so that the cost is effectively reduced.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for the embodiments will be briefly described below. It is obvious that the drawings in the following description are only some embodiments of the invention, and that for a person skilled in the art, other drawings can be derived from them without inventive effort.

Fig. 1 schematically shows a schematic structural diagram of an optical system of a large aperture lens according to a first embodiment of the present invention;

fig. 2 schematically illustrates an optical system of a large aperture lens according to a second embodiment of the present invention;

fig. 3 schematically illustrates an optical system of a large aperture lens according to a third embodiment of the present invention;

fig. 4 schematically shows a schematic structural diagram of an optical system of a large aperture lens according to a fourth embodiment of the present invention.

DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION

The embodiments described in this specification are to be considered in all respects as illustrative and not restrictive, and the appended drawings are intended to be part of the entire specification. In the drawings, the shape or thickness of the embodiments may be exaggerated and simplified for convenience. Further, the components of the structures in the drawings are described separately, and it should be noted that the components not shown or described in the drawings are in a form known to those skilled in the art.

Any reference to directions and orientations in the description of the embodiments herein is merely for convenience of description and should not be construed as limiting the scope of the present invention in any way. The following description of the preferred embodiments refers to combinations of features which may be present independently or in combination, and the present invention is not particularly limited to the preferred embodiments. The scope of the present invention is defined by the claims.

As shown in fig. 1 to 4, an embodiment of the present invention discloses a large aperture lens, including: the zoom lens includes, in order from an object side to an image side along an optical axis, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, a ninth lens L9, a tenth lens L10, an eleventh lens L11, and a twelfth lens L12. Wherein the first lens L1 and the second lens L2 all have negative optical power, and the third lens L3, the seventh lens L7, and the eleventh lens L11 all have positive optical power.

Furthermore, the large aperture lens at least comprises seven lenses with positive focal power and four lenses with negative focal power. The large aperture lens at least comprises five plastic aspheric lenses.

Regarding the lens shape, the image-side surface of the first lens L1 is concave, the third lens L3 is a biconvex lens, the object-side surfaces of the seventh lens L7 and the eleventh lens L11 are convex, and the image-side surface of the twelfth lens L12 is convex.

In an embodiment of the present invention, as shown in fig. 1, fig. 3 or fig. 4, the large aperture lens further includes a thirteenth lens L13 on the basis of the twelfth lens in the above embodiment, wherein the thirteenth lens L13 is located on the image side of the twelfth lens L12 and adjacent to the twelfth lens L12. With respect to the shape of the lens, the object-side surface of the thirteenth lens L13 is convex, and the image-side surface thereof is concave.

Furthermore, the large aperture lens at least comprises seven lenses with positive focal power and four lenses with negative focal power. The large aperture lens at least comprises five plastic aspheric lenses.

The utility model discloses an embodiment, big light ring camera lens still includes diaphragm STOP, diaphragm STOP is located third lens L3 with between the fourth lens L4, as shown in fig. 3 or fig. 4. Or the STOP is located between the fourth lens L4 and the fifth lens L5, as shown in fig. 2. Or between the sixth lens L6 and the seventh lens L7, as shown in fig. 1.

The utility model discloses an embodiment, the diaphragm STOP with central distance D1 between the adjacent lens of the image side of diaphragm STOP and with central distance D between two adjacent pieces of lens of diaphragm STOP satisfies the relational expression: D1/D is more than or equal to 0 and less than or equal to 0.5. Illustratively, as shown in fig. 1, the center distance D1 between the STOP and the seventh lens L7 and the center distance D between the sixth lens L6 and the seventh lens L7 satisfy the relationship: D1/D is more than or equal to 0 and less than or equal to 0.5. The design is such that the lens has enough space to realize the arbitrary switching of the two-gear diaphragm F/1.6 to F/0.7.

According to the above technical scheme of the utility model, adopt the optics framework by twelve pieces of lenses or thirteen pieces of lenses, the positive and negative focal power of each lens of rational distribution, the object side and the concave-convex different shapes, face type and material etc. of being like the side, can make this camera lens have super large light ring, high and the imaging quality advantage such as excellent, maximum light ring FNO =0.7, the power of resolving simultaneously reaches 5M les and requires (5M pixel requirement), guarantee to have high resolution ratio promptly under the big light ring. The hybrid optimization design of the plastic aspheric lens and the glass spherical lens overcomes the difficulty that the plastic aspheric lens is easy to cause focus drift in high and low temperature environments due to large expansion coefficient, so that the lens can realize no virtual focus within the temperature range of minus 40 ℃ to 80 ℃. In addition, the scheme of mixing the glass and plastic material lenses is successfully applied to the large-aperture lens with the imaging performance, so that the cost is effectively reduced.

In one embodiment of the present invention, the large aperture lens comprises a double cemented lens group and a triple cemented lens group. Preferably, the focal length Fa of the cemented doublet group and the effective focal length F of the large aperture lens satisfy the relation: the absolute Fa/F is more than or equal to 11 and less than or equal to 28. Through the use of the cemented lens and the reasonable arrangement of the double cemented lens group and the triple cemented lens group, the chromatic aberration of the lens can be reduced to the maximum extent, and even eliminated. Meanwhile, the focal length section of the double-cemented lens group and the relation between the focal length section and the focal length of the lens are optimally configured, so that the reflection loss of light energy is reduced, the illumination is improved, the image quality can be further improved, and the imaging definition of the lens is improved.

Preferably, the focal length Fb of the triple cemented lens group and the effective focal length F of the large aperture lens satisfy the relation: the absolute value of Fb/F is more than or equal to 4 and less than or equal to 10. The large aperture of the lens optical system is further ensured by optimally configuring the focal length section of the triple cemented lens group and the relation between the focal length section and the lens focal length, and the total optical length TTL of the optical system is shortened while the light incoming quantity is increased, so that the total optical length TTL meets the performance requirement that the TTL is less than or equal to 64.5 mm.

Preferably, a difference Vd2 in abbe's number of two lenses cemented to constitute the double cemented lens group satisfies the relation: the Vd2 is less than or equal to 40 and is more than or equal to 10, so that chromatic aberration generated during lens imaging can be eliminated as much as possible, and the resolution of the lens is improved.

Preferably, a difference Vd3 between the maximum and minimum values of abbe numbers of three lenses cemented to constitute the triple cemented lens group satisfies the relationship: the Vd3 is less than or equal to 15 and less than or equal to 50, so that chromatic aberration generated during lens imaging can be eliminated as far as possible, and the resolution of the lens is improved.

In an embodiment of the present invention, the curvature radius R1 of the object side surface of the third lens element L3 and the curvature radius R2 of the image side surface of the third lens element L3 satisfy the following relation: (R1 + R2)/(R1-R2) is not less than 0.1 and not more than 0.6. By controlling the curvature radius of the third lens L3, the spherical aberration of lens imaging can be improved, the sensitivity of a central field area is reduced, and the imaging resolution is further improved.

In an embodiment of the present invention, in the optical structure of the large aperture lens, from the object side, the combined focal length FG1 of the front group G1 of lenses composed of the first two lenses or the first three lenses and the effective focal length F of the large aperture lens satisfy the relationship: FG1/F is less than or equal to-1 and is less than or equal to-5. Therefore, the focal power of the lens front group G1 in the lens can be reasonably distributed, the excessive concentration of the focal power is avoided, the imaging quality of the lens is improved, the sensitivity of the lens is reduced, and the lens has good imaging effect at high and low temperatures.

In an embodiment of the present invention, in the optical structure of the large aperture lens, from the object side, the combined focal length FG2 of the lens rear group G2 composed of the last two lenses or the last three lenses and the effective focal length F of the large aperture lens satisfy the relation: FG2/F is more than or equal to 2 and less than or equal to 9. So set up the trend that can control light, with the smooth transition of place ahead light to the rear, increase the light flux, avoid the emergence of vignetting. The optical imaging lens is also beneficial to improving the aberration of marginal rays, improving the image quality of the optical imaging lens and reducing tolerance sensitivity.

The utility model discloses an in the embodiment, the total optical length TTL of big light ring camera lens with the entrance pupil diameter ENPD of big light ring camera lens satisfies the relational expression: TTL/ENPD is more than or equal to 7 and less than or equal to 10, the total optical length TTL of the lens is favorably controlled within a proper range, namely the total optical length TTL is less than or equal to 64.5mm, and the problems or defects of insufficient light passing quantity of the lens and the like caused by the fact that the entrance pupil diameter ENPD is too small are favorably avoided.

The utility model discloses an in the embodiment, the half high IH of the height of light ring camera lens with the optics total length TTL of light ring camera lens satisfies the relational expression: TTL/IH is not less than 11 and not more than 15, so that the miniaturization of the lens is ensured, and meanwhile, the optical imaging lens has good imaging quality.

To sum up, the utility model discloses big light ring camera lens has and guarantees to have high resolution ratio, low cost under big light ring to and can realize not virtual burnt high imaging performance at-40 ℃ -80 ℃ temperature range simultaneously. Specifically, the maximum aperture FNO =0.7, the resolution reaches the requirement of 5M pixels, the total optical length TTL is less than or equal to 64.5mm, and enough space is provided for realizing the arbitrary switching of the two-gear aperture of the iris diaphragm F/1.6 to F/0.7.

The following describes four embodiments of the large aperture lens according to the present invention with reference to the drawings and tables. In each of the following embodiments, the present invention records the STOP (including the object side surface and the image side surface) as one surface, records the bonding surface of the cemented lens assembly as one surface, records the parallel plate CG and the optical filter IR as two surfaces, and records the image plane IMA as one surface.

The parameters of each example specifically corresponding to the above relationship are shown in table 1 below:

relation formula	Example one	Example two	EXAMPLE III	Example four
					11≤|Fa/F|≤28	12.15	11.65	27.43	16.38
4≤|Fb/F|≤10	4.5	7.63	8.27	9.52
					10≤|Vd2|≤40	30.9	33	30.9	13.7
15≤|Vd3|≤50	48.6	44.8	19.7	21.4
					0.1≤(R1+R2)/(R1-R2)≤0.6	0.50	0.13	0.58	0.17
-5≤FG1/F≤-1	-3.24	-2.45	-4.68	-1.19
					2≤FG2/F≤9	8.90	2.69	3.71	7.57
0≤D1/D≤0.5	0.05	0.42	0.34	0.44
					7≤TTL/ENPD≤10	7.36	7.95	9.36	7.93
11≤|TTL/IH|≤15	12.43	13.62	14.56	11.81

TABLE 1

In an embodiment of the present invention, the aspheric lens of the large aperture lens satisfies the following formula:

in the above formula, z is the axial distance from the curved surface to the vertex at the position of the height h perpendicular to the optical axis along the optical axis direction; c represents a curvature at the vertex of the aspherical surface; k is a conic coefficient; a. The ₄ 、A ₆ 、A ₈ 、A ₁₀ 、A ₁₂ 、A ₁₄ 、A ₁₆ The aspherical coefficients of the fourth, sixth, eighth, tenth, twelfth, fourteenth and sixteenth orders are expressed respectively.

Example one

Referring to fig. 1, the parameters of the large aperture lens of the present embodiment are as follows:

image height IH =8.8mm; aperture FNO =0.7/FNO =1.6;

in the present embodiment, the fourth lens L4, the sixth lens L6, the eighth lens L8, the tenth lens L10, and the thirteenth lens L13 all have positive power, and the fifth lens L5, the ninth lens L9, and the twelfth lens L12 all have negative power. Regarding the shape of each lens, in the direction from the object side to the image side along the optical axis, the first lens L1, the seventh lens L7, the eleventh lens L11, and the thirteenth lens L13 are convex-concave lenses, the second lens L2 and the twelfth lens L12 are concave-convex lenses, the third lens L3, the fourth lens L4, the sixth lens L6, the eighth lens L8, and the tenth lens L10 are convex-convex lenses, and the fifth lens L5 and the ninth lens L9 are concave-concave lenses.

The fourth lens L4, the fifth lens L5 and the sixth lens L6 are cemented together to form a triple cemented lens group, and the ninth lens L9 and the tenth lens L10 are cemented together to form a double cemented lens group.

The parameters related to each lens in the large-aperture lens of the embodiment include: surface type, radius of curvature (R value), thickness, refractive index of the material, and abbe number, as shown in table 2 below.

TABLE 2

The aspheric coefficients of the aspheric lenses of the large-aperture lens of the embodiment include: the quadric surface constant K and the fourth-order aspheric surface coefficient A of the surface ₄ Sixth order aspherical surface coefficient A ₆ Eighth order aspherical surface coefficient A ₈ Ten-order aspheric surface coefficient A ₁₀ Twelve-order aspheric surface coefficient A ₁₂ Fourteen-order aspheric surface coefficient A ₁₄ And a sixteen-order aspheric coefficient A ₁₆ As shown in table 3 below.

TABLE 3

As shown in fig. 1 and tables 1 to 3, the large aperture lens of the present embodiment has a high resolution guaranteed under a large aperture, is low in cost, and can achieve a high imaging performance without virtual focus in a temperature range of-40 ℃ to 80 ℃. Specifically, the maximum aperture FNO =0.7, the resolution reaches the requirement of 5M pixels, the total optical length TTL is less than or equal to 64.5mm, and enough space is provided for realizing the arbitrary switching of the iris diaphragm F/1.6 to F/0.7 two-gear aperture.

Example two

Referring to fig. 2, the parameters of the large aperture lens of the present embodiment are as follows:

image height IH =8.8mm; aperture FNO =0.7/FNO =1.6;

in the present embodiment, the fourth lens L4, the fifth lens L5, the ninth lens L9, the tenth lens L10, and the twelfth lens L12 all have positive optical power, and the sixth lens L6 and the eighth lens L8 all have negative optical power. Regarding the shape of each lens, in the direction from the object side to the image side along the optical axis, the first lens L1 and the twelfth lens L12 are convex-concave lenses, the second lens L2, the sixth lens L6, and the eighth lens L8 are concave-concave lenses, the third lens L3, the fifth lens L5, the seventh lens L7, the ninth lens L9, and the eleventh lens L11 are convex-convex lenses, and the fourth lens L4 and the tenth lens L10 are concave-convex lenses.

The seventh lens L7, the eighth lens L8 and the ninth lens L9 are cemented to form a triple cemented lens group, and the second lens L2 and the third lens L3 are cemented to form a double cemented lens group.

The parameters related to each lens in the large-aperture lens of the embodiment include: the surface type, radius of curvature (R value), thickness, refractive index of the material, and abbe number are shown in table 4 below.

TABLE 4

The aspheric coefficients of the aspheric lenses of the large-aperture lens of the embodiment include: the conic surface constant K and fourth-order aspheric surface coefficient A ₄ Sixth order aspherical surface coefficient A ₆ Eighth order aspheric surface coefficient A ₈ Ten-order aspheric surface coefficient A ₁₀ Twelve-order aspheric surface coefficient A ₁₂ Fourteen-order aspheric surface coefficient A ₁₄ And a sixteen-order aspheric coefficient A ₁₆ As shown in table 5 below.

TABLE 5

As shown in fig. 2 and tables 1, 4, and 5, the large aperture lens of the present embodiment has a high resolution guaranteed under a large aperture, is low in cost, and can achieve a high imaging performance without virtual focus in a temperature range of-40 ℃ to 80 ℃. Specifically, the maximum aperture FNO =0.7, the resolution reaches the requirement of 5M pixels, the total optical length TTL is less than or equal to 64.5mm, and enough space is provided for realizing the arbitrary switching of the iris diaphragm F/1.6 to F/0.7 two-gear aperture.

EXAMPLE III

Referring to fig. 3, the parameters of the large aperture lens of the present embodiment are as follows:

image height IH =8.8mm; aperture FNO =0.7/FNO =1.6;

in the present embodiment, the fourth lens L4, the fifth lens L5, the ninth lens L9, and the twelfth lens L12 all have negative optical power, and the sixth lens L6, the eighth lens L8, the tenth lens L10, and the thirteenth lens L13 all have positive optical power. Regarding the shape of each lens, in the direction from the object side to the image side along the optical axis, the first lens L1, the fourth lens L4, the fifth lens L5, the seventh lens L7, the eleventh lens L11, and the thirteenth lens L13 are convex-concave lenses, the second lens L2 and the twelfth lens L12 are concave-convex lenses, the third lens L3, the sixth lens L6, the eighth lens L8, and the tenth lens L10 are convex-convex lenses, and the ninth lens L9 is a concave-concave lens.

The fourth lens L4, the fifth lens L5 and the sixth lens L6 are cemented to form a triple cemented lens group, and the ninth lens L9 and the tenth lens L10 are cemented to form a double cemented lens group.

The parameters related to each lens in the large-aperture lens of the embodiment include: the surface type, radius of curvature (R value), thickness, refractive index of the material, and abbe number are shown in table 6 below.

TABLE 6

The aspheric coefficients of the aspheric lenses of the large-aperture lens of the embodiment include: the quadric surface constant K and the fourth-order aspheric surface coefficient A of the surface ₄ Sixth order aspherical surface coefficient A ₆ Eighth order aspherical surface coefficient A ₈ Ten-order aspheric surface coefficient A ₁₀ Twelve-order aspheric surface coefficient A ₁₂ Fourteen-order aspheric surface coefficient A ₁₄ And a sixteen-order aspheric coefficient A ₁₆ As shown in table 7 below.

TABLE 7

As shown in fig. 3 and tables 1, 6, and 7, the large aperture lens of the present embodiment has a high resolution ensured under a large aperture, a low cost, and a high imaging performance without virtual focus in a temperature range of-40 ℃ to 80 ℃. Specifically, the maximum aperture FNO =0.7, the resolution reaches the requirement of 5M pixels, the total optical length TTL is less than or equal to 64.5mm, and enough space is provided for realizing the arbitrary switching of the iris diaphragm F/1.6 to F/0.7 two-gear aperture.

Example four

Referring to fig. 4, the parameters of the large aperture lens of the present embodiment are as follows:

image height IH =8.8mm; aperture FNO =0.7/FNO =1.6;

in the present embodiment, the fourth lens L4, the sixth lens L6, the tenth lens L10, and the thirteenth lens L13 all have negative optical power, and the fifth lens L5, the eighth lens L8, the ninth lens L9, and the twelfth lens L12 all have positive optical power. Regarding the shape of each lens, in the direction from the object side to the image side along the optical axis, the first lens L1, the sixth lens L6, and the tenth lens L10 are concave-concave lenses, the second lens L2, the fourth lens L4, and the eighth lens L8 are concave-convex lenses, the third lens L3, the fifth lens L5, the seventh lens L7, the ninth lens L9, the eleventh lens L11, and the twelfth lens L12 are convex-convex lenses, and the thirteenth lens L13 is a convex-concave lens.

The fifth lens L5, the sixth lens L6 and the seventh lens L7 are cemented to form a triple cemented lens group, and the tenth lens L10 and the eleventh lens L11 are cemented to form a double cemented lens group.

The parameters related to each lens in the large-aperture lens of the embodiment include: surface type, radius of curvature (R value), thickness, refractive index of the material, and abbe number, as shown in table 8 below.

TABLE 8

The aspheric coefficients of the aspheric lenses of the large aperture lens of the embodiment include: the quadric surface constant K and the fourth-order aspheric surface coefficient A of the surface ₄ Sixth order aspherical surface coefficient A ₆ Eighth order aspheric surface coefficient A ₈ Ten-order aspheric surface coefficient A ₁₀ Twelve-order aspheric surface coefficient A ₁₂ Fourteen-order aspheric surface coefficient A ₁₄ And a sixteen-order aspheric surface coefficient A ₁₆ As shown in table 9 below.

TABLE 9

As shown in fig. 4 and tables 1, 8, and 9, the large aperture lens of the present embodiment has a high resolution guaranteed under a large aperture, is low in cost, and can achieve high imaging performance without virtual focus in a temperature range of-40 ℃ to 80 ℃. Specifically, the maximum aperture FNO =0.7, the resolution reaches the requirement of 5M pixels, the total optical length TTL is less than or equal to 64.5mm, and enough space is provided for realizing the arbitrary switching of the iris diaphragm F/1.6 to F/0.7 two-gear aperture.

The above description is only a preferred embodiment of the present invention, and should not be taken as limiting the invention, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. A large aperture lens, comprising: a first lens (L1), a second lens (L2), a third lens (L3), a fourth lens (L4), a fifth lens (L5), a sixth lens (L6), a seventh lens (L7), an eighth lens (L8), a ninth lens (L9), a tenth lens (L10), an eleventh lens (L11), and a twelfth lens (L12) arranged in this order from the object side to the image side along the optical axis,

the focal powers of the first lens (L1) and the second lens (L2) are negative, and the focal powers of the third lens (L3), the seventh lens (L7), and the eleventh lens (L11) are positive;

the image-side surface of the first lens (L1) is concave, the third lens (L3) is a biconvex lens, the object-side surfaces of the seventh lens (L7) and the eleventh lens (L11) are convex, and the image-side surface of the twelfth lens (L12) is convex.

2. The large aperture lens according to claim 1, further comprising a thirteenth lens (L13), the thirteenth lens (L13) being located on the image side of the twelfth lens (L12).

3. The large aperture lens according to claim 2, wherein the thirteenth lens (L13) is a convex-concave lens in a direction from the object side to the image side along the optical axis.

4. The large aperture lens according to claim 1, further comprising a STOP (STOP) located between the third lens (L3) and the fourth lens (L4), between the fourth lens (L4) and the fifth lens (L5), or between the sixth lens (L6) and the seventh lens (L7).

5. The large aperture lens according to claim 4, wherein the center distance D1 between the STOP (STOP) and the lens adjacent to the image side surface of the STOP (STOP) and the center distance D between the two lenses adjacent to the STOP (STOP) satisfy the following relation: D1/D is more than or equal to 0 and less than or equal to 0.5.

6. The large aperture lens according to claim 1, wherein the large aperture lens comprises a double cemented lens group and a triple cemented lens group.

7. The large aperture lens according to claim 6, wherein the focal length Fa of the cemented doublet and the effective focal length F of the large aperture lens satisfy the relation: the absolute Fa/F is more than or equal to 11 and less than or equal to 28.

8. The large aperture lens according to claim 6, wherein the focal length Fb of the triple cemented lens group and the effective focal length F of the large aperture lens satisfy the relation: the absolute value of Fb/F is more than or equal to 4 and less than or equal to 10.

9. The large aperture lens according to claim 6, wherein the difference Vd2 between Abbe's numbers of two lenses composing the double cemented lens group satisfies the following relation: the Vd2 is less than or equal to 40 and is more than or equal to 10.

10. The large aperture lens according to claim 6, wherein a difference Vd3 between a maximum value and a minimum value of abbe numbers of three lenses composing the triple cemented lens group satisfies a relation: the Vd3 is less than or equal to 50 and is more than or equal to 15.

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