CN216210192U - Long-focus large-target-surface lens - Google Patents

Abstract

The embodiment of the utility model discloses a long-focus large-target-surface lens. The lens comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a diaphragm, a sixth lens, a seventh lens, an eighth lens, a ninth lens and a tenth lens which are arranged in sequence from an object side to an image side along an optical axis; the first lens, the fifth lens, the eighth lens and the ninth lens have positive focal power, the second lens, the sixth lens, the seventh lens and the tenth lens have negative focal power, a lens group consisting of the third lens and the fourth lens has negative focal power, a fixed-focus lens with an aperture F less than 2.1 can be realized, the full-glass lens is adopted to realize the characteristic of stable high-low temperature performance, the use condition of-40-80 ℃ can be met, meanwhile, the large target surface is provided, the 4/3' target surface sensor chip can be matched to the maximum extent, and the fixed-focus lens has the characteristics of day and night, large target surface and small purple edge.

Description

Long-focus large-target-surface lens

Technical Field

The embodiment of the utility model relates to the technical field of optical lenses, in particular to a long-focus large-target-surface lens.

Background

In recent years, with the development of security protection, the monitoring lens technology brings a new revolution for realizing networking of cameras, and the most obvious revolution of the lens is embodied in two aspects: high cleaning and large target area. In the era of networking and digitalization, the pursuit of high definition for monitoring makes the size requirement of a camera on a target surface higher and higher. Generally, the larger the area of the photosensitive device, the better the photosensitive performance, and the higher the signal-to-noise ratio, the better the imaging effect. In order to improve the picture quality, high-definition network camera products often adopt a photosensitive chip with a large target surface. However, most of the fixed focus lenses on the market at present cannot meet the requirements of a large aperture and a large target surface, and are not favorable for the networked development of monitoring lenses.

SUMMERY OF THE UTILITY MODEL

The utility model provides a long-focus large-target-surface lens which has the characteristics of day and night confocal, large target surface and small purple edge and can be matched with a sensor chip of 4/3 ″.

The embodiment of the utility model provides a long-focus large-target-surface lens which comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a diaphragm, a sixth lens, a seventh lens, an eighth lens, a ninth lens and a tenth lens which are sequentially arranged from an object space to an image space along an optical axis;

the first lens, the fifth lens, the eighth lens, and the ninth lens have positive power, the second lens, the sixth lens, the seventh lens, and the tenth lens have negative power, and a lens group of the third lens and the fourth lens has negative power.

Optionally, the third lens and the fourth lens are cemented to form a first cemented lens group, and the third lens and the fourth lens have opposite optical powers.

Optionally, the seventh lens element and the eighth lens element are cemented together to form a second cemented lens group, and the second cemented lens group has positive power or negative power.

Optionally, an object-side surface of the first lens element is a convex surface, and an image-side surface of the first lens element is a concave surface;

the object side surface of the second lens is a convex surface, and the image side surface of the second lens is a concave surface;

the object side surface of the third lens is a concave surface or a convex surface;

the object side surface of the fourth lens is a convex surface or a concave surface, and the image side surface of the fourth lens is a convex surface or a concave surface;

the object side surface of the fifth lens is a convex surface, and the image side surface of the fifth lens is a convex surface;

the object side surface of the sixth lens is a concave surface or a convex surface, and the image side surface of the sixth lens is a concave surface;

the object side surface of the seventh lens is a concave surface or a convex surface;

the object side surface of the eighth lens is a convex surface, and the image side surface of the eighth lens is a convex surface;

the object side surface of the ninth lens is a convex surface, and the image side surface of the ninth lens is a concave surface or a convex surface;

the object side surface of the tenth lens is a convex surface, and the image side surface of the tenth lens is a concave surface.

Optionally, the focal power of each lens in the telephoto large target surface lens satisfies the following condition:

0.19<ψ1/ψ<0.49；

-0.55<ψ2/ψ<-0.2；

-1.29<ψ3/ψ<0.14；

-1.40<ψ4/ψ<0.67；

1.12<ψ5/ψ<1.36；

-0.87<ψ6/ψ<-0.39；

-1.26<ψ7/ψ<-0.04；

0<ψ8/ψ<0.59；

0.67<ψ9/ψ<1.09；

-0.74<ψ10/ψ<-0.12；

where ψ is the focal power of the telephoto large target surface lens, ψ n is the focal power of the nth lens, and n is an integer of 1 to 10.

Optionally, the first lens to the tenth lens are all glass spherical lenses.

Optionally, the refractive index nd and the abbe number vd of each lens in the telephoto large target surface lens satisfy the following conditions:

1.65<L1_nd<1.99，15<L1_vd<41；

1.40<L2_nd<1.54，15<L2_vd<69；

1.40<L3_nd<1.90，15<L3_vd<95；

1.47<L4_nd<1.84，29<L4_vd<90；

1.91<L5_nd<2.05，15<L5_vd<63；

1.51<L6_nd<1.69，29<L6_vd<95；

1.81<L7_nd<2.05，15<L7_vd<31；

1.56<L8_nd<1.79，76<L8_vd<95；

1.50<L9_nd<1.82，15<L9_vd<20；

1.65<L10_nd<2.05，19<L10_vd<95；

wherein Ln _ nd is the refractive index of the nth lens, Ln _ vd is the Abbe number of the nth lens, and n is an integer of 1 to 10.

According to the telephoto large target surface lens provided by the embodiment of the utility model, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the diaphragm, the sixth lens, the seventh lens, the eighth lens, the ninth lens and the tenth lens are sequentially arranged from the object side to the image side along the optical axis; the first lens, the fifth lens, the eighth lens and the ninth lens have positive focal power, the second lens, the sixth lens, the seventh lens and the tenth lens have negative focal power, a lens group consisting of the third lens and the fourth lens has negative focal power, a fixed-focus lens with an aperture F smaller than 2.1 can be realized, the fixed-focus lens has a large target surface, can be matched with 4/3' target surface sensor chip to the maximum extent, and has the characteristics of large target surface and small purple edge.

Drawings

Fig. 1 is a schematic structural diagram of a telephoto large target surface lens provided in an embodiment of the present invention;

FIG. 2 is a graph of axial aberration for the tele large target lens shown in FIG. 1;

FIG. 3 is a plot of chromatic aberration for the tele large-target lens of FIG. 1;

fig. 4 is a schematic structural diagram of a telephoto large target surface lens according to a second embodiment of the present invention;

FIG. 5 is a graph of axial aberration for the tele large target lens shown in FIG. 4;

FIG. 6 is a plot of chromatic aberration for the tele large-target lens of FIG. 4;

fig. 7 is a schematic structural diagram of a telephoto large target surface lens according to a third embodiment of the present invention;

FIG. 8 is a graph of axial aberration for the tele large target lens of FIG. 7;

FIG. 9 is a plot of chromatic aberration for the tele large-target lens of FIG. 7;

fig. 10 is a schematic structural diagram of a telephoto large target lens according to a fourth embodiment of the present invention;

FIG. 11 is a graph of axial aberration for the tele large target lens of FIG. 10;

fig. 12 is a graph of chromatic aberration for the tele large-target lens shown in fig. 10.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the utility model and are not limiting of the utility model. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.

Fig. 1 is a schematic structural diagram of a telephoto large target lens according to an embodiment of the present invention, and referring to fig. 1, the telephoto large target lens includes a first lens 11, a second lens 12, a third lens 13, a fourth lens 14, a fifth lens 15, a diaphragm 20, a sixth lens 16, a seventh lens 17, an eighth lens 18, a ninth lens 19, and a tenth lens 110, which are arranged in order from an object side to an image side along an optical axis; the first lens 11, the fifth lens 15, the eighth lens 18, and the ninth lens 19 have positive power, the second lens 12, the sixth lens 16, the seventh lens 17, and the tenth lens 110 have negative power, and a lens group consisting of the third lens 13 and the fourth lens 14 has negative power.

Therein, it is understood that the optical power is equal to the difference between the image-side and object-side convergence, which characterizes the ability of the optical system to deflect light. The larger the absolute value of the focal power is, the stronger the bending ability to the light ray is, and the smaller the absolute value of the focal power is, the weaker the bending ability to the light ray is. When the focal power is positive, the refraction of the light is convergent; when the focal power is negative, the refraction of the light is divergent. In the telephoto large target surface lens shown in fig. 1, the first lens 11 is set to have positive refractive power, and the first lens can be used to increase the field angle of the whole lens, so as to obtain a larger image capture range. Meanwhile, a diaphragm 20 is arranged between the fifth lens 15 and the sixth lens 16, for the five lenses in front of the diaphragm, the first lens 11 and the fifth lens 15 have positive focal power, and the lens group of the second lens 12 and the third lens 13 and the fourth lens 14 has negative focal power, so that the light beams can be converged, diverged and converged again in sequence; for the five lenses behind the diaphragm, the sixth lens 16, the seventh lens 17 and the tenth lens 110 have negative power, which can ensure that the light beam passing through the diaphragm undergoes multiple divergences. From the above-mentioned light beam converging and diverging process, it can be understood that the telephoto large target surface lens can diverge the light beam as much as possible, thereby realizing a large target surface.

In addition, it should be noted that, in the above-mentioned lens combination before the diaphragm and the lens combination after the diaphragm, not all the lenses are set to negative focal power to achieve the purpose of increasing the target surface, wherein some of the lenses are set to positive focal power, so that the whole lens can be matched with positive and negative focal power, and the purpose is to correct the aberration formed in the process of converging and diverging the light beam, thereby ensuring the definition of the final image while achieving a long-focus large target surface. Further, by disposing the diaphragm between the fifth lens 15 of positive power and the sixth lens 16 of negative power, it is possible to correct off-axis aberrations with the diaphragm after the light beams are converged by the fifth lens 15, improve axial chromatic aberration, and the like.

According to the lens provided by the embodiment of the utility model, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the diaphragm, the sixth lens, the seventh lens, the eighth lens, the ninth lens and the tenth lens are sequentially arranged from the object side to the image side along the optical axis; the first lens, the fifth lens, the eighth lens and the ninth lens have positive focal power, the second lens, the sixth lens, the seventh lens and the tenth lens have negative focal power, a lens group consisting of the third lens and the fourth lens has negative focal power, a fixed-focus lens with an aperture F smaller than 2.1 can be realized, the fixed-focus lens has a large target surface, can be matched with 4/3' target surface sensor chip to the maximum extent, and has the characteristics of large target surface and small purple edge.

Optionally, in the above embodiments, the first lens to the tenth lens may be all glass spherical lenses. The glass is adopted to prepare the lens, namely the full-glass lens is adopted, the imaging quality can not be influenced by the ambient temperature, the performance stability under high and low temperature can be realized, the use condition of-40-80 ℃ is met, and the characteristic of day and night confocal is realized.

In one embodiment, the optional third lens element 13 and the fourth lens element 14 are cemented together to form the first cemented lens group 100, and the first cemented lens group 100 has negative power.

For the third lens 13 and the fourth lens 14, the opposite surface shapes are set to be the same and are cemented, so that the air gap between the two lenses can be reduced, chromatic aberration can be properly corrected, curvature of field and coma can be improved, and the imaging quality can be further optimized while the light beam divergence effect is integrally realized.

Furthermore, in a preferred embodiment, a seventh lens element 17 and an eighth lens element 18 can be further arranged to be cemented together to form a second cemented lens group 200, and the second cemented lens group 200 has positive power or negative power. Similarly, for the cemented seventh lens 17 and eighth lens 18, it is also possible to achieve improvements in chromatic aberration, curvature of field, and coma, further optimizing the imaging quality.

With continued reference to fig. 1, on the basis of the above embodiment, the object-side surface of the first lens element 11 may be a convex surface, and the image-side surface thereof may be a concave surface; the object-side surface of the second lens element 12 is convex, and the image-side surface thereof is concave; the object side surface of the third lens 13 is a concave surface or a convex surface; the object side surface of the fourth lens element 14 is convex or concave, and the image side surface is convex or concave; the object-side surface and the image-side surface of the fifth lens element 15 are convex surfaces; the object side surface of the sixth lens element 16 is concave or convex, and the image side surface is concave; the object side surface of the seventh lens element 17 is a concave surface or a convex surface; the object-side surface and the image-side surface of the eighth lens element 18 are convex surfaces; the ninth lens element 19 has a convex object-side surface and a concave or convex image-side surface; the tenth lens element 110 has a convex object-side surface and a concave image-side surface.

Wherein, because the third lens 13 is cemented with the fourth lens 14, and the seventh lens 17 is cemented with the eighth lens 18, the opposite surfaces of the two cemented lenses are substantially the same in surface type, the image-side surface of the third lens 13 is substantially identical to the object-side surface of the fourth lens 14, and the image-side surface of the seventh lens 17 is substantially identical to the object-side surface of the eighth lens 18.

With continued reference to fig. 1, in the telephoto large target surface lens, the optical powers of the selectable lenses satisfy the following conditions:

0.19<ψ1/ψ<0.49；

-0.55<ψ2/ψ<-0.2；

-1.29<ψ3/ψ<0.14；

-1.40<ψ4/ψ<0.67；

1.12<ψ5/ψ<1.36；

-0.87<ψ6/ψ<-0.39；

-1.26<ψ7/ψ<-0.04；

0<ψ8/ψ<0.59；

0.67<ψ9/ψ<1.09；

-0.74<ψ10/ψ<-0.12；

where ψ is the focal power of the telephoto large-target-plane lens, ψ n is the focal power of the nth lens, and n is an integer of 1 to 10.

The focal power range of each lens ensures that each lens has relatively fixed light beam divergence and convergence effects, axial aberration and chromatic aberration are effectively corrected by matching in the light path of the whole lens, and the aberration balance under the conditions of high temperature and low temperature is ensured while the clear imaging of a large target surface is realized.

Furthermore, the refractive index nd and the abbe number vd of each lens in the long-focus large-target-surface lens can meet the following conditions:

1.65<L1_nd<1.99，15<L1_vd<41；

1.40<L2_nd<1.54，15<L2_vd<69；

1.40<L3_nd<1.90，15<L3_vd<95；

1.47<L4_nd<1.84，29<L4_vd<90；

1.91<L5_nd<2.05，15<L5_vd<63；

1.51<L6_nd<1.69，29<L6_vd<95；

1.81<L7_nd<2.05，15<L7_vd<31；

1.56<L8_nd<1.79，76<L8_vd<95；

1.50<L9_nd<1.82，15<L9_vd<20；

1.65<L10_nd<2.05，19<L10_vd<95；

wherein Ln _ nd is the refractive index of the nth lens, Ln _ vd is the Abbe number of the nth lens, and n is an integer of 1 to 10.

It should be noted that, the glass spherical lens adopted as the lens in the above embodiments is only an optional embodiment of the present invention, and those skilled in the art can understand that, based on various requirements of aberration correction, better aberration correction effect can be achieved by designing and adopting an aspheric lens. On this basis, in order to reduce the difficulty of preparing the aspheric surface of the glass lens, a plastic lens may be selected, and a person skilled in the art may select the lens with the advantage of balancing the aberration correction effect and the stability of the glass lens at different temperatures, which is not limited herein. Moreover, the above-mentioned solution that the third lens and the fourth lens are mutually cemented and the seventh lens and the eighth lens are mutually cemented is only an alternative of the present invention, and those skilled in the art may also choose to separately dispose the third lens, the fourth lens, the seventh lens and the eighth lens, that is, a certain distance is disposed between the third lens and the fourth lens and a certain distance is disposed between the seventh lens and the eighth lens.

The description of the telephoto large target lens described above will be given below with four specific embodiments. As shown in fig. 1, in the first embodiment, the telephoto-large target lens includes a first lens 11, a second lens 12, a third lens 13, a fourth lens 14, a fifth lens 15, a diaphragm 20, a sixth lens 16, a seventh lens 17, an eighth lens 18, a ninth lens 19, and a tenth lens 110, which are arranged in this order from the object side to the image side along the optical axis; the first lens 11, the fifth lens 15, the eighth lens 18, and the ninth lens 19 have positive power, the second lens 12, the sixth lens 16, the seventh lens 17, and the tenth lens 110 have negative power, and a lens group consisting of the third lens 13 and the fourth lens 14 has negative power.

The third lens element 13 and the fourth lens element 14 are cemented together to form a first cemented lens group 100, and the first cemented lens group 100 has negative power. The seventh lens element 17 and the eighth lens element 18 are cemented together to form a second cemented lens group 200, and the second cemented lens group 200 has positive power or negative power.

More specifically, in the first embodiment, the third lens 13 has positive focal power, the fourth lens 14 has negative focal power, and the focal power of the cemented lens group consisting of the seventh lens 17 and the eighth lens 18 is positive.

In the first embodiment, the design values of the respective lenses of the telephoto large target lens are shown in table 1 below. Table 1 shows design values (F: 34.85 mm; F2.08) of a telephoto large-target lens according to an embodiment of the present invention

The surface numbers in table 1 are numbered according to the surface order of the respective lenses, where "S1" represents the front surface of the first lens, "S2" represents the rear surface of the first lens, and so on; "STO" represents the stop of the lens; the curvature radius represents the degree of curvature of the lens surface in millimeters, a positive value represents that the surface is curved to the image surface side, and a negative value represents that the surface is curved to the object surface side, wherein 'PL' represents that the surface is a plane and the curvature radius is infinite; thickness represents the central axial distance from the current surface to the next surface in millimeters; the refractive index represents the deflection capability of a material between the current surface and the next surface to light, the blank space represents that the current position is air, and the refractive index is 1; the abbe number represents the dispersion characteristic of the material between the current surface and the next surface to light, and the blank space represents that the current position is air; "ψ 1" represents the optical power of the first lens, "ψ 2" represents the optical power of the second lens, and so on.

Fig. 2 is a graph of axial aberration of the tele large target lens shown in fig. 1, and fig. 3 is a graph of chromatic aberration of the tele large target lens shown in fig. 1. As can be seen from FIG. 2, the axial aberrations of the different wavelengths of light (0.436 μm, 0.486 μm, 0.588 μm, 0.5656 μm and 0.850 μm) in the telephoto large target lens are no more than 0.09 mm. As can be seen from FIG. 3, the axial chromatic aberration generated by the light rays with different wavelengths (0.436 μm, 0.486 μm, 0.588 μm, 0.5656 μm and 0.850 μm) is within + -5 μm, especially for the light rays with purple wavelength (0.436 μm), the chromatic aberration is lower than that of the existing lens design, so that the effect of small purple edge of the large target surface lens can be realized. In summary, the long-focus large target surface provided by the embodiment of the utility model can better correct axial aberration, can ensure that imaging chromatic aberration of infrared light and visible light has smaller difference, is beneficial to realizing confocal of visible light and infrared light, and provides high-resolution and high-quality images.

Fig. 4 is a schematic structural diagram of a telephoto large target lens according to a second embodiment of the present invention, and referring to fig. 4, the telephoto large target lens includes a first lens 11, a second lens 12, a third lens 13, a fourth lens 14, a fifth lens 15, a stop 20, a sixth lens 16, a seventh lens 17, an eighth lens 18, a ninth lens 19, and a tenth lens 110, which are sequentially arranged along an optical axis from an object side to an image side; the first lens 11, the fifth lens 15, the eighth lens 18, and the ninth lens 19 have positive power, the second lens 12, the sixth lens 16, the seventh lens 17, and the tenth lens 110 have negative power, and a lens group consisting of the third lens 13 and the fourth lens 14 has negative power.

The third lens element 13 and the fourth lens element 14 are cemented together to form a first cemented lens group 100, and the first cemented lens group 100 has negative power. The seventh lens element 17 and the eighth lens element 18 are cemented together to form a second cemented lens group 200, and the second cemented lens group 200 has positive power or negative power.

More specifically, in the second embodiment, the third lens 13 has positive focal power, the fourth lens 14 has negative focal power, and the focal power of the cemented lens group consisting of the seventh lens 17 and the eighth lens 18 is positive.

In the second embodiment, the design values of the respective lenses of the telephoto large target surface lens are shown in table 2 below. Table 2 shows design values (F: 34.85 mm; F2.08) of a two-telephoto large-target lens according to an embodiment of the present invention

Fig. 5 is a graph of axial aberration of the tele large target lens shown in fig. 4, and fig. 6 is a graph of chromatic aberration of the tele large target lens shown in fig. 4. As can be seen from FIG. 5, the axial aberrations of the different wavelengths of light (0.436 μm, 0.486 μm, 0.588 μm, 0.5656 μm and 0.850 μm) in the tele large-target lens are no more than 0.09 mm. As can be seen from FIG. 6, the axial chromatic aberration generated by the light rays with different wavelengths (0.436 μm, 0.486 μm, 0.588 μm, 0.5656 μm and 0.850 μm) is within + -5 μm, especially for the light rays with purple wavelength (0.436 μm), the chromatic aberration is lower than that of the existing lens design, so that the effect of small purple edge of the large target surface lens can be realized. In summary, the long-focus large target surface provided by the second embodiment of the present invention can not only better correct the axial aberration, but also ensure that the imaging chromatic aberration of the infrared light and the visible light has smaller difference, which is beneficial to realize the confocal of the visible light and the infrared light, and provide a high-resolution and high-quality image.

Fig. 7 is a schematic structural diagram of a telephoto large target lens according to a third embodiment of the present invention, and referring to fig. 7, the telephoto large target lens similarly includes a first lens 11, a second lens 12, a third lens 13, a fourth lens 14, a fifth lens 15, a stop 20, a sixth lens 16, a seventh lens 17, an eighth lens 18, a ninth lens 19, and a tenth lens 110, which are sequentially arranged along an optical axis from an object side to an image side; the first lens 11, the fifth lens 15, the eighth lens 18, and the ninth lens 19 have positive power, the second lens 12, the sixth lens 16, the seventh lens 17, and the tenth lens 110 have negative power, and a lens group consisting of the third lens 13 and the fourth lens 14 has negative power.

The third lens element 13 and the fourth lens element 14 are cemented together to form a first cemented lens group 100, and the first cemented lens group 100 has negative power. The seventh lens element 17 and the eighth lens element 18 are cemented together to form a second cemented lens group 200, and the second cemented lens group 200 has positive power or negative power.

More specifically, in the third embodiment, the third lens 13 has positive power, the fourth lens 14 has negative power, and the power of the cemented lens group consisting of the seventh lens 17 and the eighth lens 18 is negative.

In the third embodiment, design values of the respective lenses of the telephoto large target surface lens are shown in table 3 below. Table 3 shows design values (F: 34.85 mm; F2.095) of a triple-focus large-target lens according to an embodiment of the present invention

Fig. 8 is a graph of axial aberration of the tele large target lens shown in fig. 7, and fig. 9 is a graph of chromatic aberration of the tele large target lens shown in fig. 7. As can be seen from FIG. 8, the axial aberrations of the different wavelengths of light (0.436 μm, 0.486 μm, 0.588 μm, 0.5656 μm and 0.850 μm) in the tele large-target lens are no more than 0.09 mm. As can be seen from fig. 9, the axial chromatic aberration generated by the light rays with different wavelengths (0.436 μm, 0.486 μm, 0.588 μm, 0.5656 μm and 0.850 μm) is within ± 5 μm, and especially for the light rays with the violet wavelength (0.436 μm), the chromatic aberration is lower than that of the existing lens design, so that the effect of small purple edge of the large target lens can be achieved. In summary, the large tele target surface provided by the third embodiment of the present invention can not only better correct the axial aberration, but also ensure that the imaging chromatic aberration of the infrared light and the visible light has a small difference, which is beneficial to realize the confocal of the visible light and the infrared light, and provide a high-resolution and high-quality image.

Fig. 10 is a schematic structural diagram of a telephoto large target lens according to a fourth embodiment of the present invention, and referring to fig. 10, the telephoto large target lens similarly includes a first lens 11, a second lens 12, a third lens 13, a fourth lens 14, a fifth lens 15, a stop 20, a sixth lens 16, a seventh lens 17, an eighth lens 18, a ninth lens 19, and a tenth lens 110, which are arranged in order from an object side to an image side along an optical axis; the first lens 11, the fifth lens 15, the eighth lens 18, and the ninth lens 19 have positive power, the second lens 12, the sixth lens 16, the seventh lens 17, and the tenth lens 110 have negative power, and a lens group consisting of the third lens 13 and the fourth lens 14 has negative power.

The third lens element 13 and the fourth lens element 14 are cemented together to form a first cemented lens group 100, and the first cemented lens group 100 has negative power. The seventh lens element 17 and the eighth lens element 18 are cemented together to form a second cemented lens group 200, and the second cemented lens group 200 has positive power or negative power.

More specifically, in the fourth embodiment, the third lens 13 has a negative refractive power, the fourth lens 14 has a positive refractive power, and the refractive power of the cemented lens group composed of the seventh lens 17 and the eighth lens 18 is positive.

In the fourth embodiment, design values of the respective lenses of the telephoto large target surface lens are shown in table 4 below. Table 4 shows design values (F: 34.85 mm; F2.08) of a four-telephoto large-target lens according to an embodiment of the present invention

Fig. 11 is a graph of axial aberration of the telephoto large target lens shown in fig. 10, and fig. 12 is a graph of chromatic aberration of the telephoto large target lens shown in fig. 10. As can be seen from FIG. 11, the axial aberrations of the different wavelengths of light (0.436 μm, 0.486 μm, 0.588 μm, 0.5656 μm and 0.850 μm) are no more than 0.1mm in the tele large-target lens. As can be seen from fig. 12, the axial chromatic aberration generated by the light rays with different wavelengths (0.436 μm, 0.486 μm, 0.588 μm, 0.5656 μm and 0.850 μm) is within ± 6 μm, and especially for the light rays with the violet wavelength (0.436 μm), the chromatic aberration is lower than that of the existing lens design, so that the effect of small purple edge of the large target lens can be achieved. In summary, the long-focus large target surface provided by the fourth embodiment of the present invention can not only better correct the axial aberration, but also ensure that the imaging chromatic aberration of the infrared light and the visible light has smaller difference, which is beneficial to realize the confocal of the visible light and the infrared light, and provide a high-resolution and high-quality image.

It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious modifications, rearrangements, combinations and substitutions as will now become apparent to those skilled in the art without departing from the scope of the utility model. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims (7)

1. A long-focus large-target-surface lens is characterized by comprising a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a diaphragm, a sixth lens, a seventh lens, an eighth lens, a ninth lens and a tenth lens which are sequentially arranged from an object side to an image side along an optical axis;

the first lens, the fifth lens, the eighth lens, and the ninth lens have positive power, the second lens, the sixth lens, the seventh lens, and the tenth lens have negative power, and a lens group of the third lens and the fourth lens has negative power.

2. The tele large-target lens of claim 1, wherein the third lens is cemented with the fourth lens to form a first cemented lens group, the third lens and the fourth lens having opposite optical powers.

3. The tele large-target lens of claim 2, wherein the seventh lens and the eighth lens are cemented together to form a second cemented lens group, the second cemented lens group having a positive power or a negative power.

4. The tele large-target lens of claim 3,

the object side surface of the first lens is a convex surface, and the image side surface of the first lens is a concave surface;

the object side surface of the second lens is a convex surface, and the image side surface of the second lens is a concave surface;

the object side surface of the third lens is a concave surface or a convex surface;

the object side surface of the fourth lens is a convex surface or a concave surface, and the image side surface of the fourth lens is a convex surface or a concave surface;

the object side surface of the fifth lens is a convex surface, and the image side surface of the fifth lens is a convex surface;

the object side surface of the sixth lens is a concave surface or a convex surface, and the image side surface of the sixth lens is a concave surface;

the object side surface of the seventh lens is a concave surface or a convex surface;

the object side surface of the eighth lens is a convex surface, and the image side surface of the eighth lens is a convex surface;

the object side surface of the ninth lens is a convex surface, and the image side surface of the ninth lens is a concave surface or a convex surface;

the object side surface of the tenth lens is a convex surface, and the image side surface of the tenth lens is a concave surface.

5. The tele large target lens of claim 1, wherein the focal power of each lens in the tele large target lens satisfies the following condition:

0.19<ψ1/ψ<0.49；

-0.55<ψ2/ψ<-0.2；

-1.29<ψ3/ψ<0.14；

-1.40<ψ4/ψ<0.67；

1.12<ψ5/ψ<1.36；

-0.87<ψ6/ψ<-0.39；

-1.26<ψ7/ψ<-0.04；

0<ψ8/ψ<0.59；

0.67<ψ9/ψ<1.09；

-0.74<ψ10/ψ<-0.12；

where ψ is the focal power of the telephoto large target surface lens, ψ n is the focal power of the nth lens, and n is an integer of 1 to 10.

6. The telephoto large target lens according to claim 1, wherein the first lens to the tenth lens are all glass spherical lenses.

7. The tele large target lens of claim 6, wherein the refractive index nd and the Abbe number vd of each lens in the tele large target lens satisfy the following condition:

1.65<L1_nd<1.99，15<L1_vd<41；

1.40<L2_nd<1.54，15<L2_vd<69；

1.40<L3_nd<1.90，15<L3_vd<95；

1.47<L4_nd<1.84，29<L4_vd<90；

1.91<L5_nd<2.05，15<L5_vd<63；

1.51<L6_nd<1.69，29<L6_vd<95；

1.81<L7_nd<2.05，15<L7_vd<31；

1.56<L8_nd<1.79，76<L8_vd<95；

1.50<L9_nd<1.82，15<L9_vd<20；

1.65<L10_nd<2.05，19<L10_vd<95；

wherein Ln _ nd is the refractive index of the nth lens, Ln _ vd is the Abbe number of the nth lens, and n is an integer of 1 to 10.

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