CN218471037U - Telephoto lens with large light transmission and high resolution - Google Patents

Abstract

The utility model relates to a camera lens technical field. The utility model discloses a telephoto lens with large light transmission and high resolution, which is provided with seven lenses along an optical axis in sequence from an object side to an image side; the first lens element has positive refractive index, the object side surface of the first lens element is a convex surface, the second, fifth and sixth lens elements are convex and convex lens elements with positive refractive index, and the third and fourth lens elements are concave and concave lens elements with negative refractive index; the seventh lens element has a negative refractive index, the object-side surface of the seventh lens element is concave, the temperature coefficient of the relative refractive index of the second lens element and the temperature coefficient of the relative refractive index of the sixth lens element are negative, the second lens element and the third lens element are cemented with each other, the fourth lens element and the fifth lens element are cemented with each other, and the sixth lens element and the seventh lens element are cemented with each other. The utility model has the advantages of it is big to lead to light, and the relative illumination is high, and resolution ratio is high, and imaging quality is good, and infrared confocal nature is good, satisfies the multiband formation of image, and thermal stability is good, and image planes are big.

Description

Telephoto lens with large light transmission and high resolution

Technical Field

The utility model belongs to the technical field of the camera lens, specifically relate to a telephoto lens of big through-light high resolution.

Background

In recent years, optical lenses have been developed rapidly, and have been widely applied to various fields such as smart phones, tablet computers, vehicle monitoring, security monitoring, unmanned aerial vehicle aerial photography, machine vision systems, video conferences, and the like, so that the requirements for optical lenses are also increasing.

However, the telephoto lens in the market at present has many defects, such as poor control over the transfer function, which results in low resolution, uneven definition of different views of the image obtained by the optical system, and further influences the recognition and determination of the shot object; the image plane is small, the amplification rate of the optical system is small, the object space resolution is low, the imaging is rough, the noise point of the weak light environment is large, the details are lost, and the light sensitivity of the optical system is poor; the aperture of the light passing is generally smaller, when the light entering brightness of the optical imaging system is lower in a dark low-light environment, and when the exposure time is too short, the shooting picture is darker, the corresponding exposure time can be prolonged in order to obtain enough exposure, the shooting picture is only suitable for shooting a static object, and if a moving object is shot, the smear image blurring phenomenon of the moving object is easy to occur; the relative distortion numerical value is large, the distortion control is not good enough, the problems of easy imaging and generation of visible obvious deformation of objects and inaccurate image identification are caused; only visible light is supported for use in the daytime, or the infrared confocal performance is poor at night although the infrared confocal imaging system has an infrared function, and the infrared imaging effect is not ideal, and is usually visible light + IR850nm or a combination of visible light + IR940 nm; temperature compensation and correction are poor, the inner space ring, the base and the lens mount of the optical system are subjected to temperature changes in high and low temperature environments, and the optical back focus of the optical system cannot be synchronously changed, so that the image blurring phenomenon and the like are easy to occur.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a telephoto lens of big light-passing high resolution ratio is used for solving at least one technical problem that above-mentioned exists.

In order to achieve the above purpose, the utility model adopts the technical scheme that: a telephoto lens with large light transmission and high resolution comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens in sequence from an object side to an image side along an optical axis; the first lens element to the seventh lens element each include an object-side surface facing the object side and passing the imaging light and an image-side surface facing the image side and passing the imaging light;

the first lens element has positive refractive index, and the object-side surface of the first lens element is convex;

the second lens element with positive refractive index has a convex object-side surface and a convex image-side surface;

the third lens element with negative refractive index has a concave object-side surface and a concave image-side surface;

the fourth lens element with negative refractive index has a concave object-side surface and a concave image-side surface;

the fifth lens element with positive refractive index has a convex object-side surface and a convex image-side surface;

the sixth lens element with positive refractive index has a convex object-side surface and a convex image-side surface;

the seventh lens element has a negative refractive index, and the object-side surface of the seventh lens element is concave;

the temperature coefficients of the relative refractive indexes of the second lens and the sixth lens are negative values, the second lens and the third lens are mutually glued, the fourth lens and the fifth lens are mutually glued, and the sixth lens and the seventh lens are mutually glued;

the telephoto lens system has only the first lens element to the seventh lens element.

Further, the telephoto lens further satisfies: dn2/dt < -7.0, and dn6/dt < -7.0, wherein dn2/dt is the temperature coefficient of the relative refractive index of the second lens, and dn6/dt is the temperature coefficient of the relative refractive index of the sixth lens.

Further, the telephoto lens further satisfies: vd2>65.00, vd6> -65.00, wherein vd2 is the Abbe number of the second lens and vd6 is the Abbe number of the sixth lens.

Further, the telephoto lens further satisfies: nd3-nd2<0.25, vd2-vd3>40.00, where nd2 is the refractive index of the second lens, nd3 is the refractive index of the third lens, vd2 is the Abbe number of the second lens, and vd3 is the Abbe number of the third lens.

Further, the telephoto lens further satisfies: nd7-nd6<0.25, vd6-vd7>40.00, where nd6 is the refractive index of the sixth lens, nd7 is the refractive index of the seventh lens, vd6 is the Abbe number of the sixth lens, and vd7 is the Abbe number of the seventh lens.

Further, the telephoto lens further satisfies: 0.47< | f2/f | <0.55,0.26< | f3/f | <0.32,0.26< | f4/f | <0.32,0.24< | f5/f | <0.30,0.38< | f6/f | <0.45,0.35< | f7/f | <0.45, where f is the overall focal length of the telephoto lens, f2 is the focal length of the second lens, f3 is the focal length of the third lens, f4 is the focal length of the fourth lens, f5 is the focal length of the fifth lens, f6 is the focal length of the sixth lens, and f7 is the focal length of the seventh lens.

Further, the telephoto lens further satisfies: 2.8 & ltttl/BFL & lt 3.4 & gt, where TTL is the distance on the optical axis from the object-side surface of the first lens to the image plane, and BFL is the optical back focus of the telephoto lens.

Further, the telephoto lens further satisfies: 4.0 and f/TC5<4.4, wherein f is the integral focal length of the telephoto lens, and TC5 is the thickness of the fifth lens on the optical axis.

Further, the telephoto lens further satisfies: the diaphragm is arranged between the third lens and the fourth lens.

Further, the first lens to the seventh lens are made of glass materials.

The utility model has the advantages of:

the utility model adopts seven lenses and carries out corresponding design to each lens, so that the resolution is high, the image is even, and the imaging quality is good; the image surface is large, so that the object space resolution is high, the image is fine and smooth, the weak light noise is small, the detail loss is less, and the light sensitivity is good; the light-transmitting aperture is large, the relative illumination is high, the use in a low-illumination night environment is met, the resolving power of a video is improved, and meanwhile, the image of a high-speed moving object can be captured; the distortion control is good, the obtained edge image has small deformation, and the image restoration is accurate; the infrared confocal performance is good, the imaging effect is good in the night vision state, the imaging requirements of 850nm and 940nm are met in the night vision state, and the universality and the compatibility are greatly improved; good thermal stability and no coke loss when used in the temperature range of-40 ℃ to +85 ℃.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a first embodiment of the present invention;

FIG. 2 is a graph of MTF in visible light at 435-656nm according to an embodiment of the present invention;

FIG. 3 is a graph of MTF at 850nm infrared according to an embodiment of the present invention;

FIG. 4 is a graph of MTF at 940nm according to an embodiment of the present invention;

fig. 5 is a graph showing curvature of field and distortion according to the first embodiment of the present invention;

fig. 6 is a schematic structural diagram of a second embodiment of the present invention;

FIG. 7 is a graph of MTF under visible light 435-656nm according to the second embodiment of the present invention;

FIG. 8 is a graph of MTF at 850nm infrared light according to the second embodiment of the present invention;

fig. 9 is an MTF graph of the second embodiment of the present invention under infrared light 940 nm;

fig. 10 is a graph showing curvature of field and distortion according to the second embodiment of the present invention;

fig. 11 is a schematic structural diagram of a third embodiment of the present invention;

FIG. 12 is a graph of MTF under visible light 435-656nm in a third embodiment of the present invention;

FIG. 13 is a graph of MTF of the third embodiment of the present invention under infrared light of 850 nm;

fig. 14 is an MTF graph of the third embodiment of the present invention under infrared light 940 nm;

fig. 15 is a graph showing curvature of field and distortion according to a third embodiment of the present invention;

fig. 16 is a schematic structural diagram of a fourth embodiment of the present invention;

FIG. 17 is a graph of MTF under visible light 435-656nm according to the fourth embodiment of the present invention;

FIG. 18 is a graph of MTF at 850nm infrared light according to the fourth embodiment of the present invention;

fig. 19 is an MTF graph of an embodiment four of the present invention under infrared light 940 nm;

fig. 20 is a graph showing curvature of field and distortion according to the fourth embodiment of the present invention.

Detailed Description

To further illustrate the embodiments, the present invention provides the accompanying drawings. The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the embodiments. With these references, one of ordinary skill in the art will appreciate other possible embodiments and advantages of the present invention. Elements in the figures are not drawn to scale and like reference numerals are generally used to indicate like elements.

The present invention will now be further described with reference to the accompanying drawings and detailed description.

The term "a lens element having positive refractive index (or negative refractive index)" means that the paraxial refractive index of the lens element calculated by Gaussian optics theory is positive (or negative). The term "object-side (or image-side) of a lens" is defined as the specific range of imaging light rays passing through the lens surface. The determination of the surface shape of the lens can be performed by the judgment method of a person skilled in the art, i.e., by the sign of the curvature radius (abbreviated as R value). The R value may be commonly used in optical design software, such as Zemax or CodeV. The R value is also commonly found in lens data sheets (lens data sheets) of optical design software. When the R value is positive, the object side is judged to be a convex surface; and when the R value is negative, judging that the object side surface is a concave surface. On the contrary, regarding the image side surface, when the R value is positive, the image side surface is judged to be a concave surface; when the R value is negative, the image side surface is judged to be convex.

The utility model discloses a telephoto lens with large light transmission and high resolution, which comprises a first lens to a seventh lens from an object side to an image side along an optical axis in sequence; the first lens, the second lens, the third lens and the fourth lens respectively comprise an object side surface which faces the object side and enables the imaging light to pass through and an image side surface which faces the image side and enables the imaging light to pass through; the first lens has positive refractive index, and the object side surface of the first lens is a convex surface; the second lens element with positive refractive index has a convex object-side surface and a convex image-side surface; the third lens element with negative refractive index has a concave object-side surface and a concave image-side surface; the fourth lens element with negative refractive index has a concave object-side surface and a concave image-side surface; the fifth lens element with positive refractive index has a convex object-side surface and a convex image-side surface; the sixth lens element with positive refractive index has a convex object-side surface and a convex image-side surface; the seventh lens element has a negative refractive index, and the object-side surface of the seventh lens element is concave; the temperature coefficients of the relative refractive indexes of the second lens and the sixth lens are negative values, the second lens and the third lens are mutually glued, the fourth lens and the fifth lens are mutually glued, and the sixth lens and the seventh lens are mutually glued; the telephoto lens system has only the first lens element to the seventh lens element.

The utility model adopts seven lenses and carries out corresponding design to each lens, so that the resolution is high, the image is even, and the imaging quality is good; the image surface is large, so that the object space resolution is high, the image is fine and smooth, the weak light noise point is small, the detail loss is less, and the photosensitive performance is good; the light-transmitting aperture is large, the relative illumination is high, the use in a low-illumination night environment is met, the resolving power of a video is improved, and meanwhile, the image of a high-speed moving object can be captured; distortion control is good, the obtained edge image is small in deformation, and the image restoration is accurate; the infrared confocal performance is good, the imaging effect is good in the night vision state, the imaging requirements of 850nm and 940nm are met in the night vision state, and the universality and the compatibility are greatly improved; good thermal stability and no coke loss when used in the temperature range of-40 ℃ to +85 ℃.

Preferably, the telephoto lens further satisfies: the dn2/dt < -7.0 and the dn6/dt < -7.0, wherein the dn2/dt is the relative refractive index temperature coefficient of the second lens, and the dn6/dt is the relative refractive index temperature coefficient of the sixth lens, so that the back focus variation range of the whole lens system is well controlled, and a good imaging effect is still kept when the lens system is used in a high-temperature environment and a low-temperature environment.

Preferably, the telephoto lens further satisfies: vd2 is greater than 65.00, vd6 is 65.00, wherein vd2 is the dispersion coefficient of the second lens, vd6 is the dispersion coefficient of the sixth lens, the influence of temperature change on the back focal shift of the lens is better counteracted, and the clear and non-defocusing image is ensured when the lens is used in the temperature range of-40 ℃ to +85 ℃.

Preferably, the telephoto lens further satisfies: nd3-nd2<0.25, and vd2-vd3>40.00, wherein nd2 is the refractive index of the second lens, nd3 is the refractive index of the third lens, vd2 is the dispersion coefficient of the second lens, and vd3 is the dispersion coefficient of the third lens, so that chromatic aberration is corrected better, the infrared confocal performance is optimized, and the image quality performance in the infrared band is improved.

Preferably, the telephoto lens further satisfies: nd7-nd6<0.25, and vd6-vd7>40.00, wherein nd6 is the refractive index of the sixth lens, nd7 is the refractive index of the seventh lens, vd6 is the abbe number of the sixth lens, and vd7 is the abbe number of the seventh lens, so that chromatic aberration is corrected better, infrared confocal performance is optimized, and image quality performance in an infrared band is improved.

Preferably, the telephoto lens further satisfies: 0.47< | f2/f | <0.55,0.26< | f3/f | <0.32,0.26< | f4/f | <0.32,0.24< | f5/f | <0.30,0.38< | f6/f | <0.45,0.35< | f7/f | <0.45, wherein f is the overall focal length of the telephoto lens, f2 is the focal length of the second lens, f3 is the focal length of the third lens, f4 is the focal length of the fourth lens, f5 is the focal length of the fifth lens, f6 is the focal length of the sixth lens, f7 is the focal length of the seventh lens, the focal powers of the respective lenses are reasonably distributed, aberrations are reasonably balanced, imaging quality is high, and the lenses are low, and lens yield is high.

Preferably, the telephoto lens further satisfies: 2.8 TTL/BFL are less than 3.4 less, and wherein, TTL is the object side of first lens to the distance of imaging plane on the optical axis, and BFL is burnt behind this telephoto lens's optics, is favorable to reducing the deformation volume that the lens mount produced along with temperature variation, improves the temperature drift performance, and the structure is compacter simultaneously, does benefit to the miniaturized lightweight requirement that realizes the camera lens, further increases practicality. If the lower limit value of the conditional expression is lower, the TTL is smaller, the BFL is larger, the spherical aberration correction is difficult, the system sensitivity is increased, the yield is lower, the optical back focus is larger, and the good high-low temperature athermalization performance is difficult to realize; if the value is higher than the upper limit of the conditional expression, TTL becomes large, BFL becomes small, the total length of the optical system becomes long, the back focus becomes short, and it is difficult to achieve the compact requirement of miniaturization.

Preferably, the telephoto lens further satisfies: 4.0 and f/TC5<4.4, wherein f is the integral focal length of the telephoto lens, TC5 is the thickness of the fifth lens on the optical axis, and the curvature of field of the optical system can be effectively corrected by properly controlling the core thickness value of the fifth lens. If the thickness of the core of the fifth lens is lower than the lower limit of the conditional expression, the thickness of the core of the fifth lens is too large, the processing difficulty is increased due to the too thick lens, the yield is reduced, the cost is too high, and the mass production is not facilitated; if the thickness of the core of the fifth lens is higher than the upper limit of the conditional expression, the thickness of the core of the fifth lens becomes too thin, the thin lens cannot effectively correct the field curvature, the difficulty of correcting the field curvature of the optical system is further increased, and the requirement of clear imaging of the full view field of the image plane cannot be met.

Preferably, the telephoto lens further satisfies: the diaphragm is arranged between the third lens and the fourth lens, the second and third cemented lenses and the fourth and fifth cemented lenses are of a double-Gaussian structure relative to the diaphragm, vertical axis aberration generated by the lens is better corrected, the coma aberration, the distortion and the magnification chromatic aberration are included, and the imaging quality is improved.

Preferably, the first lens to the seventh lens are made of glass materials, so that the imaging quality and the thermal stability are further improved.

The present invention will be described in detail with reference to specific embodiments.

Example one

As shown in fig. 1, a telephoto lens with large light transmission and high resolution includes, in order along an optical axis I, a first lens 1, a second lens 2, a third lens 3, a diaphragm 8, a fourth lens 4, a fifth lens 5, a sixth lens 6, a seventh lens 7, a protective glass 9, and an image plane 100 from an object side A1 to an image side A2; the first lens element 1 to the seventh lens element 7 each include an object-side surface facing the object side A1 and allowing the imaging light to pass therethrough, and an image-side surface facing the image side A2 and allowing the imaging light to pass therethrough.

The first lens element 1 has a positive refractive index, an object-side surface 11 of the first lens element 1 is a convex surface, and an image-side surface 12 of the first lens element 1 is a flat surface. Of course, in some embodiments, the image side surface 12 of the first lens 1 may also be concave, etc.

The second lens element 2 has a positive refractive index, and an object-side surface 21 of the second lens element 2 is convex and an image-side surface 22 of the second lens element 2 is convex.

The third lens element 3 has a negative refractive index, and an object-side surface 31 of the third lens element 3 is concave and an image-side surface 32 of the third lens element 3 is concave.

The fourth lens element 4 has a negative refractive index, and an object-side surface 41 of the fourth lens element 4 is concave and an image-side surface 42 of the fourth lens element 4 is concave.

The fifth lens element 5 has a positive refractive index, and an object-side surface 51 of the fifth lens element 5 is convex and an image-side surface 52 of the fifth lens element 5 is convex.

The sixth lens element 6 has a positive refractive index, and an object-side surface 61 of the sixth lens element 6 is convex and an image-side surface 62 of the sixth lens element 6 is convex.

The seventh lens element 7 with negative refractive index has a concave object-side surface 71 of the seventh lens element 7 and a convex image-side surface 72 of the seventh lens element 7. Of course, in some embodiments, the image side surface 72 of the seventh lens 7 may also be flat, concave, etc.

The relative refractive index temperature coefficient of the second lens 2 and the sixth lens 6 is a negative value.

The second lens 2 and the third lens 3 are cemented with each other, the fourth lens 4 and the fifth lens 5 are cemented with each other, and the sixth lens 6 and the seventh lens 7 are cemented with each other.

In the present embodiment, the diaphragm 8 is disposed between the third lens 3 and the fourth lens 4, but the present invention is not limited thereto, and in other embodiments, the diaphragm 8 may be disposed at another suitable position.

In this embodiment, the first lens 1 to the seventh lens 7 are made of glass material.

The detailed optical data of this example are shown in Table 1-1.

Table 1-1 detailed optical data for example one

Please refer to table 5 for the values of the conditional expressions related to this embodiment.

The visible light MTF graph of the specific embodiment is shown in detail in FIG. 2, and it can be seen that the MTF value is greater than 0.2 at 200lp/mm, the video resolution is greater than 1080P and is close to 4K, the resolution is high, the imaging quality is good, the MTF graphs of infrared bands of 850nm and 940nm are shown in detail in FIGS. 3 and 4, it can be seen that the MTF value of infrared band of 850nm is greater than 0.1, the MTF value of infrared band of 940nm is greater than 140lp/mm greater than 0.1, the infrared imaging quality is good, and the imaging requirements of 850nm and 940nm are met; the field curvature and the distortion diagram are shown in detail in (A) and (B) of FIG. 5, it can be seen that the aberrations such as the field curvature and the distortion are better corrected, the distortion values of the edge field are all less than +/-0.2%, the deformation amount of the edge field is small, and the imaging effect is good.

When the specific embodiment is used in a temperature range of-40 ℃ to +85 ℃, the picture is clear and is not defocused.

In this specific embodiment, the overall focal length f =16.3mm of the telephoto lens; aperture value FNO =1.8; the diameter of the image surface is 8.1mm; the distance TTL =23.63mm from the object-side surface 11 of the first lens 1 to the imaging surface 100 on the optical axis I, and the chief ray angle CRA =17.0 °.

Example two

As shown in fig. 6, the surface type convexo-concave and the refractive index of each lens element of the present embodiment are substantially the same as those of the first embodiment, only the image side surface 72 of the seventh lens element 7 is a flat surface, and optical parameters such as the curvature radius of the surface of each lens element and the lens thickness are different.

The detailed optical data of this embodiment is shown in Table 2-1.

TABLE 2-1 detailed optical data for example two

Please refer to table 5 for the values of the conditional expressions related to this embodiment.

The visible light MTF graph of the specific embodiment is shown in detail in FIG. 7, and the MTF value is larger than 0.2 at 200lp/mm, the video resolution is larger than 1080P and is close to 4K, the resolution is high, the imaging quality is good, the MTF graphs of the infrared bands of 850nm and 940nm are shown in detail in FIGS. 8 and 9, the MTF values of the infrared bands of 850nm and 940nm are shown to be 200lp/mm larger than 0.1, the infrared imaging quality is good, and the imaging requirements of 850nm and 940nm are met; the field curvature and distortion images are shown in (A) and (B) of fig. 10 in detail, it can be seen that the aberrations such as the field curvature and the distortion are better corrected, the distortion values of the edge fields are all less than +/-0.2%, the deformation amount of the edge fields is small, and the imaging effect is good.

When the specific embodiment is used in a temperature range of-40 ℃ to +85 ℃, the picture is clear and is not defocused.

In this specific embodiment, the overall focal length f =16.3mm of the telephoto lens; aperture value FNO =1.8; the diameter of the image surface is 8.2mm; the distance TTL =23.52mm from the object-side surface 11 of the first lens 1 to the imaging surface 100 on the optical axis I, and the chief ray angle CRA =17.1 °.

EXAMPLE III

As shown in fig. 11, in this embodiment, the surface-type convexo-concave shapes and the refractive indexes of the lenses are substantially the same as those of the first embodiment, only the image-side surface 12 of the first lens element 1 is a concave surface, and the image-side surface 72 of the seventh lens element 7 is a concave surface, and the optical parameters such as the curvature radius of the lens surfaces and the lens thickness are different.

The detailed optical data of this example are shown in Table 3-1.

TABLE 3-1 detailed optical data for EXAMPLE III

Please refer to table 5 for the values of the conditional expressions related to this embodiment.

The visible light MTF graph of the specific embodiment is shown in detail in FIG. 12, and it can be seen that the MTF value is greater than 0.2 at 200lp/mm, the video resolution is greater than 1080P and is close to 4K, the resolution is high, the imaging quality is good, the MTF graphs of infrared bands of 850nm and 940nm are shown in detail in FIGS. 13 and 14, it can be seen that the MTF value of infrared band of 850nm is greater than 0.1 at 200lp/mm, the MTF value of infrared band of 940nm is greater than 0.1 at 140lp/mm, the infrared imaging quality is good, and the imaging requirements of 850nm and 940nm are met; the field curvature and distortion images are shown in (A) and (B) of fig. 15 in detail, it can be seen that the aberrations such as the field curvature and the distortion are better corrected, the distortion values of the edge fields are all less than +/-0.2%, the deformation amount of the edge fields is small, and the imaging effect is good.

When the specific embodiment is used in a temperature range of-40 ℃ to +85 ℃, the picture is clear and is not defocused.

In this specific embodiment, the overall focal length f =16.3mm of the telephoto lens; aperture value FNO =1.8; the diameter of the image surface is 8.1mm; the distance TTL =23.94mm from the object-side surface 11 of the first lens 1 to the imaging surface 100 on the optical axis I, and the chief ray angle CRA =17.5 °.

Example four

As shown in fig. 16, in this embodiment, the surface-type convexo-concave shapes and the refractive indexes of the lenses are substantially the same as those of the first embodiment, only the image-side surface 12 of the first lens element 1 is a concave surface, and the image-side surface 72 of the seventh lens element 7 is a concave surface, and the optical parameters such as the curvature radius of the lens surfaces and the lens thickness are different.

The detailed optical data of this embodiment is shown in Table 4-1.

TABLE 4-1 detailed optical data for example four

Please refer to table 5 for the values of the conditional expressions related to this embodiment.

The visible light MTF graph of the specific embodiment is shown in detail in FIG. 17, and the MTF value is larger than 0.2 at 200lp/mm, the video resolution is larger than 1080P and is close to 4K, the resolution is high, the imaging quality is good, the MTF graphs of the infrared bands of 850nm and 940nm are shown in detail in FIGS. 18 and 19, the MTF value of the infrared band of 850nm is shown to be 200lp/mm larger than 0.1, the MTF value of the infrared band of 940nm is 140lp/mm larger than 0.08, the infrared imaging quality is good, and the imaging requirements of 850nm and 940nm are met; the field curvature and distortion diagram are shown in (a) and (B) of fig. 20 in detail, it can be seen that the aberrations such as field curvature and distortion are better corrected, the distortion values of the edge fields are all less than +/-0.3%, the deformation amount of the edge fields is small, and the imaging effect is good.

When the specific embodiment is used in a temperature range of-40 ℃ to +85 ℃, the picture is clear and is not defocused.

In this specific embodiment, the overall focal length f =16.3mm of the telephoto lens; aperture value FNO =1.8; the diameter of the image surface is 8.0mm; the distance TTL =23.95mm from the object-side surface 11 of the first lens 1 to the imaging surface 100 on the optical axis I, and the chief ray angle CRA =17.4 °.

Table 5 values of relevant important parameters of four embodiments of the present invention

	Example one	Example two	EXAMPLE III	Example four
					nd3-nd2	0.19	0.19	0.19	0.19
vd2-vd3	42.62	42.62	42.62	42.62
					nd7-nd6	0.16	0.16	0.16	0.16
vd6-vd7	43.29	43.29	43.29	43.29
					|f2/f|	0.51	0.51	0.50	0.50
|f3/f|	0.29	0.29	0.29	0.29
					|f4/f|	0.29	0.29	0.29	0.29
|f5/f|	0.26	0.26	0.26	0.26
					|f6/f|	0.41	0.41	0.40	0.40
|f7/f|	0.41	0.40	0.39	0.38
					TTL/BFL	3.08	3.07	3.15	3.15
f/TC5	4.35	4.17	4.17	4.17

While the invention has been particularly shown and described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (10)

1. A telephoto lens with large light transmission and high resolution comprises a first lens, a second lens, a third lens and a fourth lens from an object side to an image side in sequence along an optical axis; the first lens, the second lens, the third lens and the fourth lens respectively comprise an object side surface which faces the object side and enables the imaging light to pass through and an image side surface which faces the image side and enables the imaging light to pass through; the method is characterized in that:

the first lens element has positive refractive index, and the object-side surface of the first lens element is convex;

the second lens element with positive refractive index has a convex object-side surface and a convex image-side surface;

the third lens element with negative refractive index has a concave object-side surface and a concave image-side surface;

the fourth lens element with negative refractive index has a concave object-side surface and a concave image-side surface;

the fifth lens element with positive refractive index has a convex object-side surface and a convex image-side surface;

the sixth lens element with a positive refractive index has a convex object-side surface and a convex image-side surface;

the seventh lens element has a negative refractive index, and the object-side surface of the seventh lens element is concave;

the temperature coefficients of the relative refractive indexes of the second lens and the sixth lens are negative values, the second lens and the third lens are mutually glued, the fourth lens and the fifth lens are mutually glued, and the sixth lens and the seventh lens are mutually glued;

the telephoto lens system has only the first lens element to the seventh lens element.

2. A high-throughput high-resolution telephoto lens according to claim 1, wherein the telephoto lens further satisfies: dn2/dt < -7.0, and dn6/dt < -7.0, wherein dn2/dt is the temperature coefficient of the relative refractive index of the second lens, and dn6/dt is the temperature coefficient of the relative refractive index of the sixth lens.

3. A high-throughput high-resolution telephoto lens according to claim 1 or 2, wherein the telephoto lens further satisfies: vd2>65.00, vd6> -65.00, wherein vd2 is the Abbe number of the second lens and vd6 is the Abbe number of the sixth lens.

4. A high-throughput high-resolution telephoto lens according to claim 1, wherein the telephoto lens further satisfies: nd3-nd2<0.25, vd2-vd3>40.00, where nd2 is the refractive index of the second lens, nd3 is the refractive index of the third lens, vd2 is the Abbe number of the second lens, and vd3 is the Abbe number of the third lens.

5. A large-pass high-resolution telephoto lens according to claim 1 or 4, characterized in that the telephoto lens further satisfies: nd7-nd6<0.25, vd6-vd7>40.00, where nd6 is the refractive index of the sixth lens, nd7 is the refractive index of the seventh lens, vd6 is the Abbe number of the sixth lens, and vd7 is the Abbe number of the seventh lens.

6. A large-pass high-resolution telephoto lens according to claim 1, characterized in that the telephoto lens further satisfies: 0.47< | f2/f | <0.55,0.26< | f3/f | <0.32,0.26< | f4/f | <0.32,0.24< | f5/f | <0.30,0.38< | f6/f | <0.45,0.35< | f7/f | <0.45, where f is the overall focal length of the telephoto lens, f2 is the focal length of the second lens, f3 is the focal length of the third lens, f4 is the focal length of the fourth lens, f5 is the focal length of the fifth lens, f6 is the focal length of the sixth lens, and f7 is the focal length of the seventh lens.

7. A large-pass high-resolution telephoto lens according to claim 1, characterized in that the telephoto lens further satisfies: 2.8 and less than TTL/BFL <3.4, wherein TTL is the distance from the object side surface of the first lens to the imaging surface on the optical axis, and BFL is the optical back focus of the telephoto lens.

8. A large-pass high-resolution telephoto lens according to claim 1, characterized in that the telephoto lens further satisfies: 4.0 and f/TC5<4.4, wherein f is the integral focal length of the telephoto lens, and TC5 is the thickness of the fifth lens on the optical axis.

9. A high-throughput high-resolution telephoto lens according to claim 1, wherein the telephoto lens further satisfies: the diaphragm is arranged between the third lens and the fourth lens.

10. The large-pass high-resolution telephoto lens according to claim 1, characterized in that: the first lens to the seventh lens are made of glass materials.

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