CN217085399U

CN217085399U - Small fisheye lens with high resolution

Info

Publication number: CN217085399U
Application number: CN202221024578.7U
Authority: CN
Inventors: 杨成林; 于可心; 孙振中; 张春晓; 杨井留; 吴喆明; 罗艳波
Original assignee: Sirtec International Suzhou Co ltd
Current assignee: Sirtec International Suzhou Co ltd
Priority date: 2022-04-29
Filing date: 2022-04-29
Publication date: 2022-07-29
Anticipated expiration: 2032-04-29

Abstract

The utility model provides a small fisheye lens with high resolving power, which is provided with a first lens, a second lens, a third lens, a diaphragm, a fourth lens, a fifth lens, a sixth lens, a filter and an image plane IMA in sequence along the incident direction of an optical axis; the first lens has negative focal power, 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 second lens has negative focal power, 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 third lens has positive focal power, the object side surface of the third lens is a convex surface, and the image side surface of the third lens is a convex surface or a concave surface; the fourth lens has positive focal power, the object side surface of the fourth lens is a convex surface, and the image side surface of the fourth lens is a convex surface or a concave surface; the fifth lens has negative focal power, the object side surface of the fifth lens is a concave surface, and the image side surface of the fifth lens is a concave surface or a convex surface; the sixth lens has positive focal power, and the object side surface of the sixth lens is a convex surface, and the image side surface of the sixth lens is a convex surface; the lens module is simple in structure, beneficial to miniaturization of the lens module, low in cost, high in resolution and clear in imaging, and meanwhile, the lens has high relative illumination and better uniformity of image illumination.

Description

Small fisheye lens with high resolving power

Technical Field

The utility model relates to an optical imaging technical field, concretely relates to small-size fisheye lens of high resolution power.

Background

In recent years, with the development of vehicle-mounted technology, the technical requirements for a forward-looking camera device, a panoramic camera device, an automatic cruise apparatus, and a vehicle-mounted camera have been increasing. The all-round vehicle-mounted lens is an important component in an advanced driver assistance system, and a driver can visually see obstacles around the vehicle through the all-round vehicle-mounted lens, so that driving accidents are avoided.

However, the resolution of images shot by the traditional all-round camera lens is low, the size is large, the cost is high, large-angle-range shooting cannot be realized while high-definition imaging is realized, a driving auxiliary system cannot accurately judge environmental information around a vehicle in real time so as to make timely early warning or avoidance, and driving risks exist.

SUMMERY OF THE UTILITY MODEL

In order to solve the technical problem, the utility model provides a small-size fisheye lens of high resolution power and use thereof, its simple structure is favorable to the miniaturization of camera lens module, and the cost is lower, and the camera lens has high resolution power, and the formation of image is clear, and the camera lens still has the relative illumination intensity higher and better even degree of picture illumination intensity simultaneously, makes the driver can observe the peripheral barrier of car through this camera lens clarity like this, avoids driving accident's emergence.

In order to achieve the above purpose, the technical scheme of the utility model is as follows:

a small fisheye lens with high resolving power is provided with a first lens, a second lens, a third lens, a diaphragm, a fourth lens, a fifth lens, a sixth lens, a filter and an image plane IMA in sequence along the incident direction of an optical axis;

the first lens has negative focal power, 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 second lens has negative focal power, 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 third lens has positive focal power, the object side surface of the third lens is a convex surface, and the image side surface of the third lens is a convex surface or a concave surface;

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

the fifth lens has negative focal power, the object side surface of the fifth lens is a concave surface, and the image side surface of the fifth lens is a concave surface or a convex surface;

the sixth lens has positive focal power, and the object side surface of the sixth lens is a convex surface;

the maximum view field angle FOV of the small fisheye lens with high resolution, the maximum clear aperture D of the object side surface of the first lens corresponding to the maximum view angle and the image height h corresponding to the maximum view angle satisfy the following conditions:

2.2≤FOV/h/D≤2.65。

the utility model provides a small-size fisheye lens of high resolution power, its simple structure is favorable to the camera lens module miniaturization, and the cost is lower, and the camera lens has high resolution power, and the formation of image is clear, and the camera lens still has the relative illumination intensity degree of uniformity higher and better picture illumination simultaneously for the driver can be through the clear barrier of observing the car periphery of this camera lens, avoids driving accident's emergence like this.

As a preferred technical solution, the small fisheye lens with high resolution satisfies the following conditions:

TTL/f≤14.5，

wherein, TTL is the distance on the optical axis from the center of the object-side surface of the first lens element to the imaging surface of the small fisheye lens with high resolution, and f is the focal length of the entire group of lenses.

As a preferable technical scheme, the total length of the small fisheye lens with high resolution is less than 13mm, and the clear aperture of the first lens is less than 11.5 mm.

Preferably, the first lens and the third lens are glass spherical lenses, and the second lens, the fourth lens, the fifth lens and the sixth lens are plastic aspherical lenses, and aspherical surface types thereof satisfy the following conditions:

where z (h) is a distance vector from the aspheric vertex when the aspheric surface has a height h in the optical axis direction, c is 1/r, r represents a curvature radius of the aspheric mirror surface, k is a conic coefficient, and A, B, C, D, E, F, G is an aspheric high-order coefficient.

Preferably, the fourth lens and the fifth lens group are a cemented lens or a split lens, and the fifth lens and the sixth lens group are a cemented lens or a split lens.

Preferably, the first lens Nd1 is more than 1.85, and Vd1 is less than 35, wherein Nd1 refers to the refractive index of the first lens, and Vd1 refers to the Abbe number of the first lens;

the third lens 2 > Nd3 > 1.9, 20 > Vd3 > 15, wherein Nd3 refers to the refractive index of the third lens, and Vd3 refers to the Abbe number of the third lens;

the fifth lens is 1.68 & gtNd 5 & gt 1.62, and 20 & gtVd 5 & gt 18, wherein Nd5 refers to the refractive index of the fifth lens, and Vd5 refers to the Abbe number of the fifth lens.

0.18＞BFL/TTL＞0.145，

the BFL is the distance from the center of the image side surface of the sixth lens to the imaging surface of the small fisheye lens with high resolution on the optical axis; and TTL is the distance from the center of the object side surface of the first lens to the imaging surface of the small fisheye lens with high resolution on the optical axis.

22.5≤(FOV×f)/h≤23.5

the FOV is the maximum half field angle of the small fisheye lens with high resolution, f is the whole group of focal length values of the small fisheye lens with high resolution and h is the image height corresponding to the maximum field angle of the small fisheye lens with high resolution.

As a preferred technical solution, the small fisheye lens with high resolution satisfies the following conditions: f1/f is not less than 4.5 and not more than-7.5, f3/f is not less than 3 and not more than 5, and f5/f is not less than-3, wherein f1, f3 and f5 are focal lengths of the first lens, the third lens and the fifth lens in sequence.

The utility model also provides a small-size fisheye lens of high resolution is applied to vehicle autopilot as on-vehicle camera lens.

The utility model provides a small-size fisheye lens of high resolution has following beneficial effect:

1) the utility model provides a small-size fisheye lens of high resolution, its simple structure is favorable to the miniaturization of camera lens module, and the cost is lower, and the camera lens has high resolution, and the formation of image is clear, and the camera lens still has relative illumination intensity higher and better picture illumination uniformity degree simultaneously, makes the driver can clearly observe the peripheral barrier of car through this camera lens like this, avoids the emergence of driving accident;

2) the utility model provides a small-size fisheye lens of high resolution adopts 2 glass sphere lenses to add 4 plastics aspheric surface lenses, its simple structure, and the resolution is high, and is small, and the distortion is little, and the contrast is high, and is with low costs, satisfies 220 ten thousand pixel imaging requirements, can shoot the field of view scope and reach 215 degrees

Drawings

Fig. 1 is a structural view of a small fisheye lens with high resolution provided in embodiment 1 (the object side is at the leftmost position, and the image side is at the rightmost position);

fig. 2 is a graph of MTF defocus of the small fisheye lens with high resolution provided in embodiment 1;

fig. 3 is a relative illuminance diagram of the small fisheye lens with high resolution provided in embodiment 1;

fig. 4 is a structural view of a small fisheye lens providing high resolution in embodiment 2 (the object side is at the leftmost position, and the image side is at the rightmost position);

fig. 5 is a graph of MTF defocus of the small fisheye lens with high resolution provided in embodiment 2;

fig. 6 is a relative illuminance diagram of the small fisheye lens with high resolution provided in embodiment 2;

fig. 7 is a structural view of a small fisheye lens with high resolution provided in embodiment 3 (the object side is at the leftmost position, and the image side is at the rightmost position);

fig. 8 is a graph of MTF defocus for the small fisheye lens with high resolution provided in example 3;

fig. 9 is a relative illuminance diagram of the small fisheye lens with high resolution provided in embodiment 3;

fig. 10 is a structural view of a small fisheye lens with high resolution provided in example 4 (the object side is at the leftmost position, and the image side is at the rightmost position);

fig. 11 is a graph of MTF defocus for the small fisheye lens with high resolution provided in example 4;

fig. 12 is a relative illuminance diagram of the small fisheye lens with high resolution provided in example 4;

fig. 13 is a structural view of a small fisheye lens with high resolution provided in example 5 (the object side is at the leftmost position, and the image side is at the rightmost position);

fig. 14 is a graph of MTF defocus for the small fisheye lens with high resolution provided in example 5;

fig. 15 is a relative illuminance diagram of the small fisheye lens with high resolution provided in example 5;

fig. 16 is a structural view of a small fisheye lens with high resolution provided in example 6 (the object side is at the leftmost position, and the image side is at the rightmost position);

fig. 17 is a graph of MTF defocus for the small fisheye lens with high resolution provided in example 6;

fig. 18 is a relative illuminance diagram of the small fisheye lens with high resolution provided in example 6;

fig. 19 is a structural view of a small fisheye lens with high resolution provided in example 7 (the object side is at the leftmost position, and the image side is at the rightmost position);

fig. 20 is a graph of MTF defocus for the high-resolution small fisheye lens provided in example 7;

fig. 21 is a relative illuminance diagram of the small fisheye lens with high resolution provided in example 7;

wherein, 1-a first lens; 2-a second lens; 3-a third lens; 4-a fourth lens; 5-a fifth lens; 6-sixth lens; 7-a filter disc; 8-image plane IMA; 9-diaphragm.

Detailed Description

It should be noted that, the terms "first", "second", "third", "fourth", "fifth" and "sixth" are used to define the components, and are only used for the convenience of distinguishing the corresponding components, and if not stated otherwise, the above terms do not have special meanings, and therefore, the protection scope of the present invention is not to be construed as being limited.

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

It can be understood that the present invention is achieved by some embodiments.

Example 1

As shown in fig. 1, the present invention provides a small fisheye lens with high resolution, which comprises a first lens 1, a second lens 2, a third lens 3, a diaphragm 9, a fourth lens 4, a fifth lens 5, a sixth lens 6, a filter 7 and an image plane IMA8 sequentially arranged along an incident direction of an optical axis;

the first lens 1 has negative focal power, and 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 second lens 2 has negative focal power, 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 third lens 3 has positive focal power, and the object side surface of the third lens is a convex surface, and the image side surface of the third lens is a convex surface; the fourth lens 4 has positive focal power, and the object side surface of the fourth lens is a convex surface, and the image side surface of the fourth lens is a convex surface; the fifth lens 5 has negative focal power, the object side surface of the fifth lens is a concave surface, and the image side surface of the fifth lens is a concave surface; the sixth lens element 6 has positive focal power, and has a convex object-side surface and a convex image-side surface; the fourth lens 4 and the fifth lens 5 form a cemented lens; the fifth lens 5 and the sixth lens 6 form a separate lens;

the first lens 1 has negative focal power, the object side of the first lens is a convex surface, the image side surface of the first lens is a concave surface, and the first lens 1 is in a meniscus shape, so that light can be collected, distortion can be reduced, and imaging quality can be improved; the second lens 2 has negative focal power, the object side surface of the second lens is a convex surface, the image side surface of the second lens is a concave surface, and therefore the second lens is beneficial to smoothly carrying and converting light rays, reducing aberration, reducing the sensitivity of the lens and simultaneously being beneficial to reducing the caliber of the lens; the third lens 3 and the fourth lens 4 both have positive focal power, so that light rays can be favorably refracted, the length of the lens can be reduced, and the diaphragm 9 is arranged between the third lens 3 and the fourth lens 4, so that the caliber of the lens can be favorably reduced; the fifth lens 5 is a biconcave negative lens, which is beneficial to correcting field curvature and improving imaging quality;

the maximum field angle FOV of the small fisheye lens with high resolution is 103, the maximum clear aperture D of the object-side surface of the first lens 1 corresponding to the maximum field angle is 9.6, and the image height h corresponding to the maximum field angle is 4.07, where FOV/h/D is 2.6361, and the following conditional expression 2.2 or more and FOV/h/D or less than 2.65 is satisfied, so that satisfying FOV/h/D or less than 2.2 or less than 2.65 is beneficial to realizing small aperture of the front-end lens, having smaller volume, being beneficial to miniaturization of the lens module, and having lower cost.

Example 1 provides optical parameters of a small fisheye lens with high resolution as shown in table 1 below:

table 1 example 1 provides optical parameters for a high resolution small fisheye lens

In table 1, when the radii of curvature of the diaphragm, the filter, and the image plane IMA surface are infinite, this surface is a plane.

The first lens 1 meets Nd1 & gt 1.85 and Vd1 & lt 35, wherein Nd1 refers to the refractive index of the first lens, and Vd1 refers to the Abbe number of the first lens; the third lens 3 satisfies 2 > Nd3 > 1.9, 20 > Vd3 > 15, wherein Nd3 refers to the refractive index of the third lens, and Vd3 refers to the Abbe number of the third lens; the fifth lens 5 satisfies 1.68 > Nd5 > 1.62, 20 > Vd5 > 18, wherein Nd5 refers to the refractive index of the fifth lens, and Vd5 refers to the Abbe number of the fifth lens.

The first lens 1 and the third lens 3 are glass spherical lenses, and the second lens 2, the fourth lens 4, the fifth lens 5 and the sixth lens 6 are plastic aspheric lenses, and aspheric surfaces thereof satisfy the following conditions:

The second lens 2, the fourth lens 4, the fifth lens 5 and the sixth lens 6 provided in example 1 are all plastic aspherical type lenses, and optical parameters of the aspherical type lenses are shown in table 1-1:

table 1-1 optical parameters of aspherical lenses of the second lens, the fourth lens, the fifth lens and the sixth lens provided in example 1

Adopt the aspheric surface lens can correct the spherical aberration among the optical system in the design of camera lens, effectively promote the imaging quality of camera lens, second lens 2, fourth lens 4, fifth lens 5 and sixth lens 6 are all the incident angle that can also reduce light for plastics aspheric surface type lens in addition, improve the relative illuminance of camera lens, can also effectively reduce the head size of camera lens, prevent that the camera lens size is too big can not use.

The TTL of the lens system on the optical axis from the center of the object-side surface of the first lens element 1 to the image plane of the small fisheye lens with high resolution is 13, the focal length f of the entire lens group is 0.9, and TTL/f is 14.444, which satisfies the following conditions: TTL/f is less than or equal to 14.5, wherein TTL is the distance between the center of the object side surface of the first lens 1 and the imaging surface of the small fisheye lens with high resolution on the optical axis, and f is the focal length of the whole group of lenses, the TTL/f in the embodiment is less than or equal to 14.5, so that the lens is more beneficial to miniaturization, and the total length of the lens is proved to be smaller and has smaller volume; the total length of the small fisheye lens with high resolution is 12.5mm, and the clear aperture of the first lens 1 is 11 mm; the volume is smaller, and the miniaturization of the module is more facilitated.

The distance BFL on the optical axis from the center of the image-side surface of the sixth lens element 6 to the imaging surface of the small fisheye lens with high resolution is 2.09, the distance TTL on the optical axis from the center of the object-side surface of the first lens element 1 to the imaging surface of the small fisheye lens with high resolution is 13, and the BFL/TTL is 0.161, and the following conditions are satisfied: 0.18 is larger than BFL/TTL is larger than 0.145, wherein BFL is the distance from the center of the image side surface of the sixth lens 6 to the imaging surface of the small fisheye lens with high resolution on the optical axis; and TTL is the distance from the center of the object side surface of the first lens 1 to the imaging surface of the small fisheye lens with high resolution on the optical axis, and further 0.18 is more than BFL/TTL is more than 0.145, so that the optical back focus of the lens can be increased, and sufficient space is reserved for a module.

The maximum half field angle FOV of the small fisheye lens with high resolution is 103, the entire focal length value f of the small fisheye lens with high resolution is 0.9, the image height h corresponding to the maximum field angle of the small fisheye lens with high resolution is 4.07, and (FOV × f)/h is 22.776, which satisfies the following conditions: the FOV xf/h is more than or equal to 22.5 and less than or equal to 23.5, wherein the FOV is the maximum half field angle of the small fisheye lens with high resolution, f is the whole group focal length value of the small fisheye lens with high resolution and h is the image height corresponding to the maximum field angle of the small fisheye lens with high resolution, and further, the FOV xf/h is more than or equal to 22.5 and less than or equal to 23.5, and the three indexes are controlled to be beneficial to reducing the lens distortion;

the small fisheye lens with high resolution meets the following conditions: f1/f is not less than 4.5 and not more than-7.5, f3/f is not less than 3 and not more than-5, and f5/f is not less than-3, wherein f1, f3 and f5 are focal lengths of the first lens 1, the third lens 3 and the fifth lens 5 in sequence; by reasonably matching the focal length of the lens, the assembly sensitivity is favorably reduced, the drift of the lens is controlled in a small range after high and low temperature, and the requirement of clear imaging is met.

As shown in fig. 2, the MTF defocus graph of the high-resolution small fish-eye lens provided in embodiment 1, where the ordinate of the MTF defocus graph is the MTF value, and the abscissa is the distance of the image point from the paraxial image plane, and the MTF defocus graph of the lens reflects the resolution capability of the lens, is concentrated in the 80LP defocus MTF curve and has a high MTF value, which can reflect that the lens has a high resolution and is clear in imaging.

As shown in fig. 3, the relative illuminance map of the small fisheye lens with high resolution provided in example 1, where the ordinate of the relative illuminance map is an illuminance value and the abscissa is an angle of view, and the relative illuminance map of the lens reflects the uniformity of the illuminance of the image of the lens, and the maximum angle of view of the small fisheye lens with high resolution in this example is 206 °, the relative illuminance is greater than 0.3, which reflects that the lens has higher relative illuminance and better uniformity of the illuminance of the image.

The small fisheye lens with high resolution provided by the embodiment has the advantages that the structure is simple, the miniaturization of the lens module is facilitated, the cost is lower, the lens has high resolution, the imaging is clear, meanwhile, the lens has the uniform degree of the relative illumination, the image illumination is higher and better, the driver can clearly observe the peripheral obstacles of the vehicle through the lens, and the driving accident is avoided.

Example 2

As shown in fig. 4, the present invention provides a small fisheye lens with high resolution, which is sequentially disposed along the incident direction of the optical axis, a first lens 1, a second lens 2, a third lens 3, a diaphragm 9, a fourth lens 4, a fifth lens 5, a sixth lens 6, a filter 7, and an image plane IMA 8;

the first lens 1 has negative focal power, and 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 second lens 2 has negative focal power, 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 third lens 3 has positive focal power, and the object side surface of the third lens is a convex surface, and the image side surface of the third lens is a convex surface; the fourth lens 4 has positive focal power, and the object side surface of the fourth lens is a convex surface, and the image side surface of the fourth lens is a convex surface; the fifth lens 5 has negative focal power, the object side surface of the fifth lens is a concave surface, and the image side surface of the fifth lens is a concave surface; the sixth lens element 6 has positive focal power, and has a convex object-side surface and a convex image-side surface; the fourth lens 4 and the fifth lens 5 form a separate lens; the fifth lens 5 and the sixth lens 6 form a cemented lens;

the first lens 1 has negative focal power, the object side of the first lens is a convex surface, the image side surface of the first lens is a concave surface, and the first lens 1 is in a meniscus shape, so that light can be collected, distortion can be reduced, and imaging quality can be improved; the second lens 2 has negative focal power, the object side surface of the second lens is a convex surface, the image side surface of the second lens is a concave surface, and therefore the second lens is beneficial to smoothly carrying and converting light rays, reducing aberration, reducing the sensitivity of the lens and simultaneously being beneficial to reducing the caliber of the lens; the third lens 3 and the fourth lens 4 both have positive focal power, so that light rays can be favorably refracted, the length of the lens can be reduced, and the diaphragm is arranged between the third lens 3 and the fourth lens 4, so that the caliber of the lens can be favorably reduced; the fifth lens 5 is a biconcave negative lens, which is beneficial to correcting field curvature and improving imaging quality;

the maximum field angle FOV of the small fisheye lens with high resolution is 103, the maximum clear aperture D of the object side surface of the first lens 1 corresponding to the maximum field angle is 10.8, the image height h corresponding to the maximum field angle is 4.07, FOV/h/D is 2.6361, the following conditional expression that FOV/h/D is greater than or equal to 2.2 and less than or equal to 2.65 is satisfied, and FOV/h/D is greater than or equal to 2.2 and less than or equal to 2.65 is satisfied, so that the small aperture of the front-end lens is realized, the small volume is obtained, the miniaturization of the lens module is facilitated, and the cost is low.

Example 2 provides optical parameters of a small fisheye lens with high resolution as shown in table 2 below:

table 2 example 2 provides optical parameters for a high resolution small fisheye lens

In table 2, the radius of curvature of the surfaces of the diaphragm 9, the filter 7 and the image plane IMA8 is infinite, indicating that the surfaces are flat.

Example 2 provides the second lens 2, the fourth lens 4, the fifth lens 5, and the sixth lens 6 each as a plastic aspherical lens, and the optical parameters of the aspherical lens are as shown in table 2-1:

table 2-1 optical parameters of aspherical lenses of the second lens, the fourth lens, the fifth lens and the sixth lens provided in example 2

The TTL of the lens system on the optical axis from the center of the object-side surface of the first lens element 1 to the image plane of the small fisheye lens with high resolution is 12.9, the focal length f of the whole lens group is 0.90, and TTL/f is 14.333, which satisfies the following conditions: TTL/f is less than or equal to 14.5, wherein TTL is the distance between the center of the object side surface of the first lens and the imaging surface of the small fisheye lens with high resolution on the optical axis, and f is the focal length of the whole group of lenses, the TTL/f in the embodiment is less than or equal to 14.5, so that the lens is more beneficial to miniaturization, and the total length of the lens is proved to be smaller and has smaller volume; the total length of the small fisheye lens with high resolution is 12mm, and the clear aperture of the first lens 1 is 10.5 mm; the volume is smaller, and the miniaturization of the module is more facilitated.

The distance BFL between the center of the image-side surface of the sixth lens element 6 and the imaging surface of the small fisheye lens with high resolution on the optical axis is 2.3, the distance TTL between the center of the object-side surface of the first lens element 1 and the imaging surface of the small fisheye lens with high resolution on the optical axis is 12.9, and the BFL/TTL is 0.178, which satisfies the following conditions: 0.18 is greater than BFL/TTL is greater than 0.145, wherein BFL is the distance from the center of the image side surface of the sixth lens element 6 to the imaging surface of the small fisheye lens with high resolution on the optical axis; and TTL is the distance from the center of the object side surface of the first lens 1 to the imaging surface of the small fisheye lens with high resolution on the optical axis, and further 0.18 is more than BFL/TTL is more than 0.145, so that the optical back focus of the lens can be increased, and sufficient space is reserved for a module.

The maximum half field angle FOV of the small fisheye lens with high resolution is 103, the entire focal length value f of the small fisheye lens with high resolution is 0.90, the image height h corresponding to the maximum field angle of the small fisheye lens with high resolution is 4.07, and (FOV × f)/h is 22.776, which satisfies the following conditions: the FOV xf/h is more than or equal to 22.5 and less than or equal to 23.5, wherein the FOV is the maximum half field angle of the small fisheye lens with high resolution, f is the whole group focal length value of the small fisheye lens with high resolution and h is the image height corresponding to the maximum field angle of the small fisheye lens with high resolution, and further, the FOV xf/h is more than or equal to 22.5 and less than or equal to 23.5, and the three indexes are controlled to be beneficial to reducing the lens distortion;

the small fisheye lens with high resolution meets the following conditions: f1/f is not less than 4.5 and not more than-7.5, f3/f is not less than 3 and not more than-5, and f5/f is not less than-3, wherein f1, f3 and f5 are focal lengths of the first lens 1, the third lens 3 and the fifth lens 5 in sequence; by reasonably matching the focal length of the lens, the assembly sensitivity is favorably reduced, the drift of the lens is controlled in a small range after the lens is at high and low temperature, and the requirement of clear imaging is met.

As shown in fig. 5, the MTF defocus graph of the high-resolution small fish-eye lens provided in embodiment 2, where the ordinate of the MTF defocus graph is the MTF value, and the abscissa is the distance of the image point from the paraxial image plane, and the MTF defocus graph of the lens reflects the resolution capability of the lens, is concentrated in the 80LP defocus MTF curve and has a high MTF value, which can reflect that the lens has a high resolution and is clear in imaging.

As shown in fig. 6, the relative illuminance map of the small fisheye lens with high resolution provided in example 2, where the ordinate of the relative illuminance map is an illuminance value and the abscissa is an angle of view, and the relative illuminance map of the lens reflects the uniformity of the illuminance of the image of the lens, and the maximum angle of view of the small fisheye lens with high resolution in this example is 206 °, the relative illuminance is greater than 0.3, which reflects that the lens has higher relative illuminance and better uniformity of the illuminance of the image.

Example 3

As shown in fig. 7, the present invention provides a small fisheye lens with high resolution, which is sequentially disposed along the incident direction of the optical axis, a first lens 1, a second lens 2, a third lens 3, a diaphragm 9, a fourth lens 4, a fifth lens 5, a sixth lens 6, a filter 7, and an image plane IMA 8;

the first lens 1 has negative focal power, and 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 second lens 2 has negative focal power, 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 third lens 3 has positive focal power, and the object side surface of the third lens is a convex surface, and the image side surface of the third lens is a convex surface; the fourth lens 4 has positive focal power, and the object side surface of the fourth lens is a convex surface, and the image side surface of the fourth lens is a convex surface; the fifth lens 5 has negative focal power, the object side surface of the fifth lens is a concave surface, and the image side surface of the fifth lens is a convex surface; the sixth lens element 6 has positive focal power, and has a convex object-side surface and a convex image-side surface; the fourth lens 4 and the fifth lens 5 form a cemented lens; the fifth lens 5 and the sixth lens 6 form a separate lens;

the first lens 1 has negative focal power, the object side of the first lens is a convex surface, the image side surface of the first lens is a concave surface, and the first lens 1 is in a meniscus shape, so that light can be collected, distortion can be reduced, and imaging quality can be improved; the second lens 2 has negative focal power, the object side surface of the second lens is a convex surface, the image side surface of the second lens is a concave surface, and therefore the second lens is beneficial to smoothly carrying and converting light rays, reducing aberration, reducing the sensitivity of the lens and simultaneously being beneficial to reducing the caliber of the lens; the third lens 3 and the fourth lens 4 both have positive focal power, so that light rays can be favorably refracted, the length of the lens can be reduced, and the diaphragm is arranged between the third lens 3 and the fourth lens 4, so that the caliber of the lens can be favorably reduced;

the maximum field angle FOV of the small fisheye lens with high resolution is 103, the maximum clear aperture D of the object-side surface of the first lens 1 corresponding to the maximum field angle is 11.16, the image height h corresponding to the maximum field angle is 4.07, FOV/h/D is 2.268, the following conditional expression 2.2 or more FOV/h/D is less than or equal to 2.65, and the conditional expression 2.2 or more FOV/h/D is less than or equal to 2.65 is favorable for realizing small aperture of the front-end lens, has smaller volume, is favorable for miniaturization of the lens module, and is low in cost.

Example 3 provides optical parameters of a small fisheye lens with high resolution as shown in table 3 below:

table 3 example 3 provides optical parameters for a high resolution small fisheye lens

In table 3, when the radii of curvature of the diaphragm, the filter, and the image plane IMA surface are infinite, this surface is a plane.

The first lens 1 meets Nd1 & gt 1.85 and Vd1 & lt 35, wherein Nd1 refers to the refractive index of the first lens 1, and Vd1 refers to the Abbe number of the first lens 1; the third lens 3 satisfies 2 > Nd3 > 1.9, 20 > Vd3 > 15, wherein Nd3 refers to the refractive index of the third lens 3, and Vd3 refers to the Abbe number of the third lens 3; the fifth lens 5 satisfies 1.68 > Nd5 > 1.62, 20 > Vd5 > 18, wherein Nd5 refers to the refractive index of the fifth lens 5, and Vd5 refers to the Abbe number of the fifth lens 5.

Example 3 provides the second lens 2, the fourth lens 4, the fifth lens 5, and the sixth lens 6 each as a plastic aspherical lens, and the optical parameters of the aspherical lens are as shown in table 3-1:

table 3-1 optical parameters of aspherical lenses of the second lens, the fourth lens, the fifth lens and the sixth lens provided in example 3

The TTL of the lens system on the optical axis from the center of the object-side surface of the first lens element 1 to the image plane of the small fisheye lens with high resolution is 12.6, the focal length f of the whole lens group is 0.918, and TTL/f is 13.725, which satisfies the following conditions: TTL/f is less than or equal to 14.5, wherein TTL is the distance between the center of the object side surface of the first lens 1 and the imaging surface of the small fisheye lens with high resolution on the optical axis, and f is the focal length of the whole group of lenses, the TTL/f in the embodiment is less than or equal to 14.5, so that the lens is more beneficial to miniaturization, and the total length of the lens is proved to be smaller and has smaller volume; the total length of the small fisheye lens with high resolution is 11.5mm, and the clear aperture of the first lens is 10 mm; the volume is smaller, and the miniaturization of the module is more facilitated.

The distance BFL on the optical axis from the center of the image-side surface of the sixth lens element 6 to the imaging surface of the small fisheye lens with high resolution is 2.06, the distance TTL on the optical axis from the center of the object-side surface of the first lens element 1 to the imaging surface of the small fisheye lens with high resolution is 12.6, and the BFL/TTL is 0.163, and the following conditions are satisfied: 0.18 is greater than BFL/TTL is greater than 0.145, wherein BFL is the distance from the center of the image side surface of the sixth lens element 6 to the imaging surface of the small fisheye lens with high resolution on the optical axis; and TTL is the distance from the center of the object side surface of the first lens 1 to the imaging surface of the small fisheye lens with high resolution on the optical axis, and further 0.18 is more than BFL/TTL is more than 0.145, so that the optical back focus of the lens can be increased, and sufficient space is reserved for a module.

The maximum half field angle FOV of the small fisheye lens with high resolution is 103, the entire focal length value f of the small fisheye lens with high resolution is 0.918, the image height h corresponding to the maximum field angle of the small fisheye lens with high resolution is 4.07, and the following conditions are satisfied (FOV × f)/h is 23.232: the FOV xf/h is more than or equal to 22.5 and less than or equal to 23.5, wherein the FOV is the maximum half field angle of the small fisheye lens with high resolution, f is the whole group focal length value of the small fisheye lens with high resolution and h is the image height corresponding to the maximum field angle of the small fisheye lens with high resolution, and further, the FOV xf/h is more than or equal to 22.5 and less than or equal to 23.5, and the three indexes are controlled to be beneficial to reducing the lens distortion;

As shown in fig. 8, the MTF defocus graph of the high-resolution small fish-eye lens provided in embodiment 3, where the ordinate of the MTF defocus graph is the MTF value, and the abscissa is the distance of the image point from the paraxial image plane, and the MTF defocus graph of the lens reflects the resolution capability of the lens, is concentrated in the MTF defocus curve of 80LP and the MTF value is high, and can reflect that the lens has high resolution and clear image.

As shown in fig. 9, the relative illuminance map of the small fisheye lens with high resolution provided in example 3, where the ordinate of the relative illuminance map is an illuminance value and the abscissa is an angle of view, and the relative illuminance map of the lens reflects the uniformity of the illuminance of the image of the lens, and the maximum angle of view of the small fisheye lens with high resolution in this example 206 ° is greater than 0.3, which reflects that the lens has higher relative illuminance and better uniformity of the illuminance of the image.

Example 4

As shown in fig. 10, the present invention provides a small fisheye lens with high resolution, which is sequentially disposed along the incident direction of the optical axis, a first lens 1, a second lens 2, a third lens 3, a diaphragm 9, a fourth lens 4, a fifth lens 5, a sixth lens 6, a filter 7, and an image plane IMA 8;

the maximum field angle FOV of the small fisheye lens with high resolution is 103, the maximum clear aperture D of the object-side surface of the first lens 1 corresponding to the maximum field angle is 11.5, the image height h corresponding to the maximum field angle is 4.07, FOV/h/D is 2.201, the following conditional expression that FOV/h/D is greater than or equal to 2.2 and less than or equal to 2.65 is satisfied, and FOV/h/D is greater than or equal to 2.2 and less than or equal to 2.65 is satisfied, so that the small aperture of the front-end lens is realized, the small volume is obtained, the miniaturization of the lens module is facilitated, and the cost is low.

Example 4 provides optical parameters of a small fisheye lens with high resolution as shown in table 4 below:

table 4 example 4 provides optical parameters for a high resolution small fisheye lens

In table 4, when the radii of curvature of the diaphragm, the filter, and the image plane IMA surface are infinite, this surface is a plane.

Wherein the first lens 1 and the third lens 3 are glass spherical lenses, and the second lens 2, the fourth lens 4, the fifth lens 5 and the sixth lens 6 are plastic aspheric lenses, and the aspheric surfaces thereof satisfy the following conditions:

Example 4 provides the second lens 2, the fourth lens 4, the fifth lens 5, and the sixth lens 6 each as a plastic aspherical lens, and the optical parameters of the aspherical lens are as shown in table 4-1:

table 4-1 optical parameters of aspherical lenses of the second lens, fourth lens, fifth lens and sixth lens provided in example 4

The TTL of the lens system on the optical axis from the center of the object-side surface of the first lens element 1 to the image plane of the small fisheye lens with high resolution is 12.9, the focal length f of the whole lens group is 0.92, and TTL/f is 14.022, which satisfies the following conditions: TTL/f is less than or equal to 14.5, wherein TTL is the distance between the center of the object side surface of the first lens 1 and the imaging surface of the small fisheye lens with high resolution on the optical axis, and f is the focal length of the whole group of lenses, the TTL/f in the embodiment is less than or equal to 14.5, so that the lens is more beneficial to miniaturization, and the total length of the lens is proved to be smaller and has smaller volume; the total length of the small fisheye lens with high resolution is 11.3mm, and the clear aperture of the first lens is 10.2 mm; the volume is smaller, and the miniaturization of the module is more facilitated.

The distance BFL between the center of the image-side surface of the sixth lens element 6 and the imaging surface of the small fisheye lens with high resolution on the optical axis is 1.9, the distance TTL between the center of the object-side surface of the first lens element 1 and the imaging surface of the small fisheye lens with high resolution on the optical axis is 12.9, and the BFL/TTL is 0.147, which satisfies the following conditions: 0.18 is greater than BFL/TTL is greater than 0.145, wherein BFL is the distance from the center of the image side surface of the sixth lens element 6 to the imaging surface of the small fisheye lens with high resolution on the optical axis; and TTL is the distance from the center of the object side surface of the first lens 1 to the imaging surface of the small fisheye lens with high resolution on the optical axis, and further 0.18 is more than BFL/TTL is more than 0.145, so that the optical back focus of the lens can be increased, and sufficient space is reserved for a module.

The maximum half field angle FOV of the small fisheye lens with high resolution is 103, the entire focal length value f of the small fisheye lens with high resolution is 0.92, the image height h corresponding to the maximum field angle of the small fisheye lens with high resolution is 4.07, and the following conditions are satisfied (FOV × f)/h is 23.283: the FOV xf/h is more than or equal to 22.5 and less than or equal to 23.5, wherein the FOV is the maximum half field angle of the small fisheye lens with high resolution, f is the whole group focal length value of the small fisheye lens with high resolution and h is the image height corresponding to the maximum field angle of the small fisheye lens with high resolution, and further, the FOV xf/h is more than or equal to 22.5 and less than or equal to 23.5, and the three indexes are controlled to be beneficial to reducing the lens distortion;

As shown in fig. 11, the MTF defocus graph of the high-resolution small fish-eye lens provided in embodiment 4, where the ordinate of the MTF defocus graph is the MTF value, and the abscissa is the distance of the image point from the paraxial image plane, and the MTF defocus graph of the lens reflects the resolution capability of the lens, is concentrated in the 80LP defocus MTF curve and has a high MTF value, which can reflect that the lens has a high resolution and is clear in imaging.

As shown in fig. 12, the relative illuminance diagram of the high-resolution small fisheye lens in embodiment 4 is provided, wherein the ordinate of the relative illuminance diagram is an illuminance value, the abscissa is an angle of view, and the relative illuminance diagram of the lens reflects the uniformity of the illuminance of the screen of the lens.

Example 5

As shown in fig. 13, the present invention provides a small fisheye lens with high resolution, which is sequentially disposed along the incident direction of the optical axis, a first lens 1, a second lens 2, a third lens 3, a diaphragm 9, a fourth lens 4, a fifth lens 5, a sixth lens 6, a filter 7, and an image plane IMA 8;

the first lens 1 has negative focal power, and 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 second lens 2 has negative focal power, 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 third lens 3 has positive focal power, and the object side surface of the third lens is a convex surface, and the image side surface of the third lens is a convex surface; the fourth lens 4 has positive focal power, and the object-side surface of the fourth lens is a convex surface, and the image-side surface of the fourth lens is a convex surface; the fifth lens 5 has negative focal power, the object side surface of the fifth lens is a concave surface, and the image side surface of the fifth lens is a convex surface; the sixth lens element 6 has positive focal power, and has a convex object-side surface and a convex image-side surface; the fourth lens 4 and the fifth lens 5 constitute a cemented lens; the fifth lens 5 and the sixth lens 6 form a separate lens;

the maximum field angle FOV of the small fisheye lens with high resolution is 103, the maximum clear aperture D of the object side surface of the first lens 1 corresponding to the maximum field angle is 11.3, the image height h corresponding to the maximum field angle is 4.07, the FOV/h/D is 2.24, the following conditional expression that the FOV/h/D is more than or equal to 2.2 and less than or equal to 2.65 is satisfied, and the FOV/h/D is more than or equal to 2.2 and less than or equal to 2.65 is satisfied, so that the small aperture of the front-end lens is realized, the small size is realized, the miniaturization of a lens module is facilitated, and the cost is low.

Example 5 optical parameters of a small fisheye lens with high resolution are shown in table 5 below:

table 5 example 5 provides optical parameters for a high resolution small fisheye lens

In table 5, when the radii of curvature of the diaphragm, the filter, and the image plane IMA surface are infinite, this surface is a plane.

The first lens 1 meets Nd1 & gt 1.85 and Vd1 & lt 35, wherein Nd1 refers to the refractive index of the first lens 1, and Vd1 refers to the Abbe number of the first lens 1; the third lens 3 satisfies 2 > Nd3 > 1.9, 20 > Vd3 > 15, wherein Nd3 refers to the refractive index of the third lens 3, and Vd3 refers to the Abbe number of the third lens 3; the fifth lens 5 satisfies 1.68 > Nd5 > 1.62, and 20 > Vd5 > 18, wherein Nd5 refers to the refractive index of the fifth lens 5, and Vd5 refers to the Abbe number of the fifth lens 5.

Example 5 provides the second lens 2, the fourth lens 4, the fifth lens 5, and the sixth lens 6 each as a plastic aspherical lens, and the optical parameters of the aspherical lens are as shown in table 5-1:

table 5-1 optical parameters of aspherical lenses of the second lens, the fourth lens, the fifth lens and the sixth lens provided in example 5

The TTL of the lens system on the optical axis from the center of the object-side surface of the first lens element 1 to the image plane of the small fisheye lens with high resolution is 12.9, the focal length f of the whole lens group is 0.913, and TTL/f is 14.129, which satisfies the following conditions: TTL/f is less than or equal to 14.5, wherein TTL is the distance between the center of the object side surface of the first lens 1 and the imaging surface of the small fisheye lens with high resolution on the optical axis, and f is the focal length of the whole group of lenses, the TTL/f in the embodiment is less than or equal to 14.5, so that the lens is more beneficial to miniaturization, and the total length of the lens is proved to be smaller and has smaller volume; the total length of the small fisheye lens with high resolution is 11.4mm, and the clear aperture of the first lens is 10.3 mm; the volume is smaller, and the miniaturization of the module is more facilitated.

The distance BFL between the center of the image-side surface of the sixth lens element 6 and the imaging surface of the small fisheye lens with high resolution on the optical axis is 2, the distance TTL between the center of the object-side surface of the first lens element 1 and the imaging surface of the small fisheye lens with high resolution on the optical axis is 12.9, and the BFL/TTL is 0.155, which satisfies the following conditions: 0.18 is greater than BFL/TTL is greater than 0.145, wherein BFL is the distance from the center of the image side surface of the sixth lens element 6 to the imaging surface of the small fisheye lens with high resolution on the optical axis; and TTL is the distance from the center of the object side surface of the first lens 1 to the imaging surface of the small fisheye lens with high resolution on the optical axis, and further 0.18 is more than BFL/TTL is more than 0.145, so that the optical back focus of the lens can be increased, and sufficient space is reserved for a module.

The maximum half field angle FOV of the small fisheye lens with high resolution is 103, the entire focal length value f of the small fisheye lens with high resolution is 0.913, the image height h corresponding to the maximum field angle of the small fisheye lens with high resolution is 4.07, and the following conditions are satisfied (FOV × f)/h is 23.105: the FOV xf/h is more than or equal to 22.5 and less than or equal to 23.5, wherein the FOV is the maximum half field angle of the small fisheye lens with high resolution, f is the whole group focal length value of the small fisheye lens with high resolution and h is the image height corresponding to the maximum field angle of the small fisheye lens with high resolution, and further, the FOV xf/h is more than or equal to 22.5 and less than or equal to 23.5, and the three indexes are controlled to be beneficial to reducing the lens distortion;

As shown in fig. 14, the MTF defocus graph of the high-resolution small fish-eye lens provided in embodiment 5, where the ordinate of the MTF defocus graph is the MTF value, and the abscissa is the distance of the image point from the paraxial image plane, and the MTF defocus graph of the lens reflects the resolution capability of the lens, is concentrated in the MTF defocus curve of 80LP and the MTF value is high, and can reflect that the lens has high resolution and clear image.

As shown in fig. 15, the relative illuminance map of the small fisheye lens with high resolution provided in example 5, where the ordinate of the relative illuminance map is an illuminance value and the abscissa is an angle of view, and the relative illuminance map of the lens reflects the uniformity of the illuminance of the image on the lens, and the maximum angle of view of the small fisheye lens with high resolution in this example 206 ° is greater than 0.3, which reflects that the lens has higher relative illuminance and better uniformity of the illuminance on the image.

Example 6

As shown in fig. 16, the present invention provides a small fisheye lens with high resolution, which is sequentially disposed along the incident direction of the optical axis, a first lens 1, a second lens 2, a third lens 3, a diaphragm 9, a fourth lens 4, a fifth lens 5, a sixth lens 6, a filter 7, and an image plane IMA 8;

the maximum field angle FOV of the small fisheye lens with high resolution is 103, the maximum clear aperture D of the object-side surface of the first lens 1 corresponding to the maximum field angle is 10.1, the image height h corresponding to the maximum field angle is 4.07, FOV/h/D is 2.506, the following conditional expression that FOV/h/D is greater than or equal to 2.2 and less than or equal to 2.65 is satisfied, and FOV/h/D is greater than or equal to 2.2 and less than or equal to 2.65 is satisfied, so that the small aperture of the front-end lens is realized, the small volume is obtained, the miniaturization of the lens module is facilitated, and the cost is low.

Example 6 optical parameters of a small fisheye lens with high resolution are shown in table 6 below:

table 6 example 6 provides optical parameters for a high resolution small fisheye lens

In table 6, when the radii of curvature of the diaphragm, the filter, and the image plane IMA surface are infinite, this surface is a plane.

Example 6 provides the second lens 2, the fourth lens 4, the fifth lens 5, and the sixth lens 6 each as a plastic aspherical lens, and optical parameters of the aspherical lens are shown in table 6-1:

table 6-1 optical parameters of aspherical lenses of the second lens, the fourth lens, the fifth lens and the sixth lens provided in example 6

The TTL of the lens system on the optical axis from the center of the object-side surface of the first lens element 1 to the image plane of the small fisheye lens with high resolution is 12.9, the focal length f of the whole lens group is 0.91, and TTL/f is 14.176, which satisfies the following conditions: TTL/f is less than or equal to 14.5, wherein TTL is the distance between the center of the object side surface of the first lens 1 and the imaging surface of the small fisheye lens with high resolution on the optical axis, and f is the focal length of the whole group of lenses, the TTL/f in the embodiment is less than or equal to 14.5, so that the lens is more beneficial to miniaturization, and the total length of the lens is proved to be smaller and has smaller volume; the total length of the small fisheye lens with high resolution is 11.2mm, and the clear aperture of the first lens is 10.1 mm; the volume is smaller, and the miniaturization of the module is more facilitated.

The distance BFL between the center of the image-side surface of the sixth lens element 6 and the imaging surface of the small fisheye lens with high resolution on the optical axis is 2.05, the distance TTL between the center of the object-side surface of the first lens element 1 and the imaging surface of the small fisheye lens with high resolution on the optical axis is 12.9, and the BFL/TTL is 0.159, which satisfies the following conditions: 0.18 is greater than BFL/TTL is greater than 0.145, wherein BFL is the distance from the center of the image side surface of the sixth lens element 6 to the imaging surface of the small fisheye lens with high resolution on the optical axis; and TTL is the distance from the center of the object side surface of the first lens 1 to the imaging surface of the small fisheye lens with high resolution on the optical axis, and further 0.18 is more than BFL/TTL is more than 0.145, so that the optical back focus of the lens can be increased, and sufficient space is reserved for a module.

The maximum half field angle FOV of the small fisheye lens with high resolution is 103, the entire focal length value f of the small fisheye lens with high resolution is 0.91, the image height h corresponding to the maximum field angle of the small fisheye lens with high resolution is 4.07, and the following conditions are satisfied (FOV × f)/h is 23.029: the FOV xf/h is more than or equal to 22.5 and less than or equal to 23.5, wherein the FOV is the maximum half field angle of the small fisheye lens with high resolution, f is the whole group focal length value of the small fisheye lens with high resolution and h is the image height corresponding to the maximum field angle of the small fisheye lens with high resolution, and further, the FOV xf/h is more than or equal to 22.5 and less than or equal to 23.5, and the three indexes are controlled to be beneficial to reducing the lens distortion;

As shown in fig. 17, the MTF defocus graph of the high-resolution small fish-eye lens provided in embodiment 6, where the ordinate of the MTF defocus graph is the MTF value, and the abscissa is the distance of the image point from the paraxial image plane, and the MTF defocus graph of the lens reflects the resolution capability of the lens, is concentrated in the 80LP defocus MTF curve and has a high MTF value, which can reflect that the lens has a high resolution and is clear in imaging.

As shown in fig. 18, the relative illuminance map of the small fisheye lens with high resolution provided in example 6, where the ordinate of the relative illuminance map is an illuminance value and the abscissa is an angle of view, and the relative illuminance map of the lens reflects the uniformity of the illuminance of the image on the lens, and the maximum angle of view of the small fisheye lens with high resolution in this example is 206 °, the relative illuminance is greater than 0.3, which reflects that the lens has higher relative illuminance and better uniformity of the illuminance on the image.

Example 7

As shown in fig. 19, the present invention provides a small fisheye lens with high resolution, which is sequentially disposed along the incident direction of the optical axis, a first lens 1, a second lens 2, a third lens 3, a diaphragm 9, a fourth lens 4, a fifth lens 5, a sixth lens 6, a filter 7, and an image plane IMA 8;

the first lens 1 has negative focal power, and 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 second lens 2 has negative focal power, 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 third lens 3 has positive focal power, and the object side surface of the third lens is a convex surface, and the image side surface of the third lens is a convex surface; the fourth lens 4 has positive focal power, and the object side surface of the fourth lens is a convex surface, and the image side surface of the fourth lens is a convex surface; the fifth lens 5 has negative focal power, the object side surface of the fifth lens is a concave surface, and the image side surface of the fifth lens is a concave surface; the sixth lens element 6 has positive focal power, and has a convex object-side surface and a convex image-side surface; the fourth lens 4 and the fifth lens 5 constitute a cemented lens; the fifth lens 5 and the sixth lens 6 form a separate lens;

the first lens 1 has negative focal power, the object side of the first lens is a convex surface, the image side surface of the first lens is a concave surface, and the first lens 1 is in a meniscus shape, so that light can be collected, distortion can be reduced, and imaging quality can be improved; the second lens 2 has negative focal power, 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, so that the second lens is beneficial to smoothly bearing the converted light rays, reducing the aberration, reducing the sensitivity of the lens and simultaneously being beneficial to reducing the caliber of the lens; the third lens 3 and the fourth lens 4 both have positive focal power, so that light rays can be favorably refracted, the length of the lens can be reduced, and the diaphragm is arranged between the third lens 3 and the fourth lens 4, so that the caliber of the lens can be favorably reduced;

the maximum field angle FOV of the small fisheye lens with high resolution is 103, the maximum clear aperture D of the object side surface of the first lens 1 corresponding to the maximum field angle is 10.3, the image height h corresponding to the maximum field angle is 4.07, the FOV/h/D is 2.457, the following conditional expression that the FOV/h/D is more than or equal to 2.2 and less than or equal to 2.65 is satisfied, and the FOV/h/D is more than or equal to 2.2 and less than or equal to 2.65 is favorable for realizing small aperture of the front-end lens, has smaller volume, is favorable for miniaturization of a lens module, and is lower in cost.

Example 7 provides optical parameters of a small fisheye lens with high resolution as shown in table 7 below:

table 7 example 7 provides optical parameters for a high resolution small fisheye lens

In table 7, when the radii of curvature of the diaphragm, the filter, and the image plane IMA surface are infinite, this surface is a plane.

Example 7 provides the second lens 2, the fourth lens 4, the fifth lens 5, and the sixth lens 6 each being a plastic aspherical lens, and optical parameters of the aspherical lens are shown in table 7-1:

table 7-1 optical parameters of aspherical lenses of the second lens, the fourth lens, the fifth lens and the sixth lens provided in example 7

The TTL of the lens system on the optical axis from the center of the object-side surface of the first lens element 1 to the image plane of the small fisheye lens with high resolution is 12.8, the focal length f of the whole lens group is 0.9, and TTL/f is 14.222, which satisfies the following conditions: TTL/f is less than or equal to 14.5, wherein TTL is the distance between the center of the object side surface of the first lens 1 and the imaging surface of the small fisheye lens with high resolution on the optical axis, and f is the focal length of the whole group of lenses, the TTL/f in the embodiment is less than or equal to 14.5, so that the lens is more beneficial to miniaturization, and the total length of the lens is proved to be smaller and has smaller volume; the total length of the small fisheye lens with high resolution is 11.1mm, and the clear aperture of the first lens is 10.0 mm; the volume is smaller, and the miniaturization of the module is more facilitated.

The distance BFL between the center of the image-side surface of the sixth lens element 6 and the image plane of the small fisheye lens with high resolution on the optical axis is 2.04, the distance TTL between the center of the object-side surface of the first lens element 1 and the image plane of the small fisheye lens with high resolution on the optical axis is 12.8, and the BFL/TTL is 0.159, which satisfies the following conditions: 0.18 is greater than BFL/TTL is greater than 0.145, wherein BFL is the distance from the center of the image side surface of the sixth lens element 6 to the imaging surface of the small fisheye lens with high resolution on the optical axis; and TTL is the distance from the center of the object side surface of the first lens 1 to the imaging surface of the small fisheye lens with high resolution on the optical axis, and further 0.18 is more than BFL/TTL is more than 0.145, so that the optical back focus of the lens can be increased, and sufficient space is reserved for a module.

The maximum half field angle FOV of the small fisheye lens with high resolution is 103, the entire focal length value f of the small fisheye lens with high resolution is 0.9, the image height h corresponding to the maximum field angle of the small fisheye lens with high resolution is 4.07, and the following conditions are satisfied (FOV × f)/h is 22.776: the FOV xf/h is more than or equal to 22.5 and less than or equal to 23.5, wherein the FOV is the maximum half field angle of the small fisheye lens with high resolution, f is the whole group focal length value of the small fisheye lens with high resolution and h is the image height corresponding to the maximum field angle of the small fisheye lens with high resolution, and further, the FOV xf/h is more than or equal to 22.5 and less than or equal to 23.5, and the three indexes are controlled to be beneficial to reducing the lens distortion;

the small fisheye lens with high resolution meets the following conditions: f1/f is not less than 4.5 and not more than-7.5, f3/f is not less than 3 and not more than-5, and f5/f is not less than-3, wherein f1, f3 and f5 are focal lengths of the first lens 1, the third lens 3 and the fifth lens 5 in sequence; through reasonable collocation of the focal length of the lens, the assembly sensitivity is favorably reduced, the high and low temperature back focal drift of the lens is controlled in a very small range, and the clear imaging is met.

As shown in fig. 20, the MTF defocus graph of the high-resolution small fish-eye lens provided in embodiment 7, where the ordinate of the MTF defocus graph is the MTF value, and the abscissa is the distance of the image point from the paraxial image plane, and the MTF defocus graph of the lens reflects the resolution capability of the lens, is concentrated in the MTF defocus curve of 80LP and the MTF value is high, and can reflect that the lens has high resolution and clear image.

As shown in fig. 21, the relative illuminance map of the small fisheye lens with high resolution provided in example 7, where the ordinate of the relative illuminance map is an illuminance value and the abscissa is an angle of view, and the relative illuminance map of the lens reflects the uniformity of the illuminance of the image on the lens, and the maximum angle of view of the small fisheye lens with high resolution in this example is 206 °, the relative illuminance is greater than 0.3, which reflects that the lens has higher relative illuminance and better uniformity of the illuminance on the image.

The small fisheye lens with high resolution provided by the embodiments 1-7 is applied to automatic driving of a vehicle as an on-vehicle lens, so that a driver can clearly observe obstacles around the vehicle through the lens, and driving accidents are avoided.

It is to be understood that the present invention has been described with respect to certain embodiments and that various changes in the features and embodiments, and equivalents thereof, may be substituted for elements thereof without departing from the spirit and scope of the invention as defined by the appended claims. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, the present invention is not to be limited to the specific embodiments disclosed herein, and all modifications and equivalents that fall within the scope of the claims of the present application are intended to be embraced therein. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of the present application are intended to be covered by the present invention.

Claims

1. A small fisheye lens with high resolving power is characterized in that a first lens, a second lens, a third lens, a diaphragm, a fourth lens, a fifth lens, a sixth lens, a filter and an image plane IMA are sequentially arranged along the incident direction of an optical axis;

2.2≤FOV/h/D≤2.65。

2. the high-resolution small fisheye lens according to claim 1, characterized in that the high-resolution small fisheye lens satisfies the following condition:

TTL/f≤14.5，

3. The small fisheye lens with high resolution as claimed in claim 1, wherein the total length of the small fisheye lens with high resolution is less than 13mm, and the clear aperture of the first lens is less than 11.5 mm.

4. The small fisheye lens with high resolving power as claimed in claim 1, wherein the first lens and the third lens are glass spherical lenses, and the second lens, the fourth lens, the fifth lens and the sixth lens are plastic aspherical lenses, and the aspherical surfaces thereof satisfy the following conditions:

5. The small fisheye lens with high resolution of claim 1, wherein the fourth lens and the fifth lens group are cemented lenses or split lenses, and the fifth lens and the sixth lens group are cemented lenses or split lenses.

6. The small fisheye lens with high resolution of claim 1, wherein the first lens is Nd1 > 1.85, Vd1<35, wherein Nd1 refers to the refractive index of the first lens, and Vd1 refers to the Abbe number of the first lens;

7. The high-resolution small fisheye lens according to claim 1, characterized in that the high-resolution small fisheye lens satisfies the following condition:

0.18＞BFL/TTL＞0.145，

8. The high-resolution small fisheye lens according to claim 1, characterized in that the high-resolution small fisheye lens satisfies the following condition:

22.5≤(FOV×f)/h≤23.5

9. The high-resolution small fisheye lens according to claim 1, characterized in that the high-resolution small fisheye lens satisfies the following condition: f1/f is not less than 4.5 and not more than-7.5, f3/f is not less than 3 and not more than 5, f5/f is not less than-3, wherein f1, f3 and f5 are focal lengths of the first lens, the third lens and the fifth lens in sequence.