阅读说明：本技术 一种鱼眼镜头和成像装置 (Fisheye lens and imaging device ) 是由 张云涛 梁晓云 于 2021-07-09 设计创作，主要内容包括：本发明涉及光学领域,具体为一种鱼眼镜头和成像装置。所述鱼眼镜头从物面侧到像面侧依次包括：负光焦度的第一透镜,负光焦度的第二透镜,正光焦度的第三透镜,光阑,正光焦度的第四透镜,负光焦度的第五透镜,正光焦度的第六透镜,其中,第四透镜和第五透镜胶合；TTL＜23mm；IH/TTL＞0.25；其中,TTL为所述鱼眼镜头的光学总长,IH为所述鱼眼镜头的像高。通过上述结构的设置,实现了小体积的鱼眼镜头,同时还增大了鱼眼镜头的像高,且鱼眼镜头能够适用于靶面较大的传感器。(The invention relates to the field of optics, in particular to a fisheye lens and an imaging device. The fisheye lens sequentially comprises from the object plane side to the image plane side: the lens comprises a first lens with negative focal power, a second lens with negative focal power, a third lens with positive focal power, a diaphragm, a fourth lens with positive focal power, a fifth lens with negative focal power and a sixth lens with positive focal power, wherein the fourth lens and the fifth lens are glued; TTL is less than 23 mm; IH/TTL is more than 0.25; wherein, TTL is the optical total length of the fisheye lens, and IH is the image height of the fisheye lens. Through the arrangement of the structure, the fisheye lens with the small size is realized, the image height of the fisheye lens is increased, and the fisheye lens can be suitable for a sensor with a large target surface.)

1. The fisheye lens is characterized by sequentially comprising the following components from an object plane side to an image plane side:

the lens comprises a first lens with negative focal power, a second lens with negative focal power, a third lens with positive focal power, a diaphragm, a fourth lens with positive focal power, a fifth lens with negative focal power and a sixth lens with positive focal power, wherein the fourth lens and the fifth lens are glued;

TTL＜23mm；

IH/TTL＞0.25；

wherein, TTL is the optical total length of the fisheye lens, and IH is the image height of the fisheye lens.

2. A fish-eye lens according to claim 1, characterized in that:

the fisheye lens meets the following conditional expression:

0.55＜Φ1/TTL＜0.8；

wherein Φ 1 is an outer diameter of the first lens.

3. A fish-eye lens according to claim 1, characterized in that:

the fisheye lens meets the following conditional expression:

Vd4＞40；

and/or

Vd6＞40；

Wherein Vd4 is the Abbe number of the fourth lens, and Vd6 is the Abbe number of the sixth lens.

4. A fish-eye lens according to claim 1, characterized in that:

the fisheye lens meets the following conditional expression:

-0.8＜R52/R61＜-0.55；

wherein, R52 is a curvature radius of the curved surface of the fifth lens on the side close to the image plane, and R61 is a curvature radius of the curved surface of the sixth lens on the side close to the object plane.

5. A fisheye lens according to claim 1 or 4, characterised in that:

the fisheye lens meets the following conditional expression:

0.75＜φ5/φ6＜0.9；

wherein φ 5 is the outer diameter of the fifth lens element, and φ 6 is the outer diameter of the sixth lens element.

6. The fisheye lens of claim 5, wherein:

the sixth lens satisfies the following conditional expression:

0.1＜D6/TTL＜0.3；

wherein D6 is the thickness of the sixth lens.

7. A fish-eye lens according to claim 1, characterized in that:

the fisheye lens meets the following conditional expression:

Nd1＞1.9；

and/or

Nd3＞1.9；

And/or

Nd5＞1.9；

Wherein Nd1 is a refractive index of the first lens, Nd3 is a refractive index of the third lens, and Nd5 is a refractive index of the fifth lens.

8. A fish-eye lens according to claim 1, characterized in that:

the fisheye lens meets the following conditional expression:

-3.5＜f1/f＜-2.5；

-3＜f2/f＜-2；

wherein f is a focal length of the fisheye lens, f1 is a focal length of the first lens, and f2 is a focal length of the second lens.

9. An image forming apparatus comprising:

the fisheye lens of any of claims 1 to 8;

and an imaging element configured to receive an image formed by the fisheye lens.

Technical Field

The invention relates to the field of optics, in particular to a fisheye lens and an imaging device.

Background

The fish-eye lens is a special lens and is characterized by having a field angle larger than 180 degrees and a large field range. The method has special application in the field of security consumption camera shooting.

However, the fisheye lens needs more space to correct various aberrations due to too large field angle, which leads to larger volume and higher cost. The fisheye lens with small volume has small image circle and cannot be applied to a sensor with a large target surface, which is a pain point of the product on the market at present.

Disclosure of Invention

The invention solves the technical problems in the prior art, and provides the fisheye lens and the imaging device, so that the fisheye lens with small volume is realized, the image height of the fisheye lens is increased, and the fisheye lens can be suitable for a sensor with a large target surface.

The technical scheme provided by the invention is as follows:

a fisheye lens comprising, in order from an object plane side to an image plane side:

the lens comprises a first lens with negative focal power, a second lens with negative focal power, a third lens with positive focal power, a diaphragm, a fourth lens with positive focal power, a fifth lens with negative focal power and a sixth lens with positive focal power, wherein the fourth lens and the fifth lens are glued;

TTL＜23mm；

IH/TTL＞0.25；

wherein, TTL is the optical total length of the fisheye lens, and IH is the image height of the fisheye lens.

In this technical scheme, through the setting of above-mentioned structure, realized the fisheye lens of small volume, still increased the image height of fisheye lens simultaneously, and the fisheye lens can be applicable to the great sensor of target surface.

Preferably, the fisheye lens satisfies the following conditional expression:

0.55＜Φ1/TTL＜0.8；

wherein Φ 1 is an outer diameter of the first lens.

In the technical scheme, the caliber of the front end of the fisheye lens is effectively limited by limiting the outer diameter of the first lens, so that the small volume of the fisheye lens and the extremely large field angle of the fisheye lens are realized.

Preferably, the fisheye lens satisfies the following conditional expression:

Vd4＞40；

and/or

Vd6＞40；

Wherein Vd4 is the Abbe number of the fourth lens, and Vd6 is the Abbe number of the sixth lens.

In the technical scheme, the abbe numbers of the fourth lens and the sixth lens are limited, so that the generation of chromatic aberration of the fisheye lens is reduced, and the imaging quality of the fisheye lens is improved.

Preferably, the fisheye lens satisfies the following conditional expression:

-0.8＜R52/R61＜-0.55；

wherein, R52 is a curvature radius of the curved surface of the fifth lens on the side close to the image plane, and R61 is a curvature radius of the curved surface of the sixth lens on the side close to the object plane.

In the technical scheme, the fifth lens and the sixth lens are close to the limitation of curvature radiuses of the curved surfaces on the two sides, so that chromatic aberration and coma aberration of the fisheye lens are reduced, and the imaging quality of the fisheye lens is improved.

Preferably, the fisheye lens satisfies the following conditional expression:

0.75＜φ5/φ6＜0.9；

wherein φ 5 is the outer diameter of the fifth lens element, and φ 6 is the outer diameter of the sixth lens element.

Among this technical scheme, through the injecing of fifth lens and sixth lens external diameter, increased the colour difference and the coma of fisheye lens border position, also increased the sensor that fisheye lens can use simultaneously, increased fisheye lens's application scope.

Preferably, the sixth lens satisfies the following conditional expression:

0.1＜D6/TTL＜0.3；

wherein D6 is the thickness of the sixth lens.

In the technical scheme, through the thickness of the sixth lens, the chromatic aberration and the coma aberration of the light at the rear end of the diaphragm are reduced, and the imaging quality of the fisheye lens is improved.

Preferably, the fisheye lens satisfies the following conditional expression:

Nd1＞1.9；

and/or

Nd3＞1.9；

And/or

Nd5＞1.9；

Wherein Nd1 is a refractive index of the first lens, Nd3 is a refractive index of the third lens, and Nd5 is a refractive index of the fifth lens.

In the technical scheme, the field angle of the lens is effectively enlarged, various aberrations of an optical system are reduced, and the distortion and the chromatic aberration of the fisheye lens are effectively controlled by limiting the refractive index of each lens.

Preferably, the fisheye lens satisfies the following conditional expression:

-3.5＜f1/f＜-2.5；

-3＜f2/f＜-2；

wherein f is a focal length of the fisheye lens, f1 is a focal length of the first lens, and f2 is a focal length of the second lens.

In the technical scheme, the field angle of the fisheye lens is effectively increased through the limitation of the focal lengths of the first lens and the second lens, and the large field angle of the fisheye lens is realized.

It is also an object of the present invention to provide an image forming apparatus comprising: a fisheye lens; and an imaging element configured to receive an image formed by the fisheye lens.

Compared with the prior art, the fisheye lens and the imaging device provided by the invention have the following beneficial effects:

1. through the arrangement of the structure, the fisheye lens with the small size is realized, the image height of the fisheye lens is increased, and the fisheye lens can be suitable for a sensor with a large target surface.

2. The aperture of the front end of the fisheye lens is effectively limited by limiting the outer diameter of the first lens, so that the small size of the fisheye lens and the extremely large angle of view of the fisheye lens are realized.

3. The generation of chromatic aberration of the fisheye lens is reduced and the imaging quality of the fisheye lens is improved by limiting the Abbe numbers of the fourth lens and the sixth lens.

4. Through the restriction of the outer diameters of the fifth lens and the sixth lens, the chromatic aberration and the coma aberration of the edge position of the fisheye lens are increased, the sensor which can be used by the fisheye lens is also increased, and the application range of the fisheye lens is enlarged.

Drawings

The above features, technical features, advantages and implementations of a fisheye lens and imaging device will be further explained in a clearly understandable manner with reference to the accompanying drawings.

Fig. 1 is a schematic structural diagram of a fisheye lens according to the invention;

FIG. 2 is an aberration diagram of a fish-eye lens according to the present invention;

fig. 3 is a coma diagram of a fish-eye lens according to the present invention;

FIG. 4 is a schematic structural diagram of another fisheye lens of the invention;

FIG. 5 is an aberration diagram of another fish-eye lens of the present invention;

fig. 6 is a coma diagram of another fish-eye lens of the present invention;

FIG. 7 is a schematic structural diagram of another fish-eye lens of the present invention;

fig. 8 is an aberration diagram of still another fish-eye lens according to the present invention;

fig. 9 is a coma aberration diagram of still another fish-eye lens according to the present invention.

The reference numbers illustrate: l1, first lens; l2, second lens; l3, third lens; l4, fourth lens; l5, fifth lens; l6, sixth lens; STO, stop; FI. An optical filter; CG. And (4) protecting the glass.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

For the sake of simplicity, only the parts relevant to the invention are schematically shown in the drawings, and they do not represent the actual structure as a product. In addition, in order to make the drawings concise and understandable, components having the same structure or function in some of the drawings are only schematically illustrated or only labeled. In this document, "one" means not only "only one" but also a case of "more than one".

Example 1

A fisheye lens comprising, in order from an object plane side to an image plane side:

a first lens L1 of negative power, a second lens L2 of negative power, a third lens L3 of positive power, a stop STO, a fourth lens L4 of positive power, a fifth lens L5 of negative power, a sixth lens L6 of positive power, wherein the fourth lens L4 and the fifth lens L5 are cemented.

TTL＜23mm；

IH/TTL＞0.25；

Wherein, TTL is the optical total length of the fisheye lens, and IH is the image height of the fisheye lens.

In this embodiment, through the setting of above-mentioned structure, realized the fisheye lens of small volume, still increased the image height of fisheye lens simultaneously, and the fisheye lens can be applicable to the great sensor of target surface.

The fisheye lens meets the following conditional expression:

0.55＜Φ1/TTL＜0.8；

where Φ 1 is the outer diameter of the first lens L1.

In this embodiment, the aperture of the front end of the fisheye lens is effectively limited by the limitation of the outer diameter of the first lens L1, so that the small volume of the fisheye lens and the extremely large field angle of the fisheye lens are realized.

The fisheye lens meets the following conditional expression:

Vd4＞40；

and/or

Vd6＞40；

Wherein Vd4 is the abbe number of the fourth lens L4, and Vd6 is the abbe number of the sixth lens L6.

In this embodiment, due to the limitation of abbe numbers of the fourth lens L4 and the sixth lens L6, the generation of chromatic aberration of the fisheye lens is reduced, and the imaging quality of the fisheye lens is improved.

The fisheye lens meets the following conditional expression:

-0.8＜R52/R61＜-0.55；

wherein R52 is a radius of curvature of the fifth lens L5 on the image plane side, and R61 is a radius of curvature of the sixth lens L6 on the object plane side.

In this embodiment, the fifth lens L5 and the sixth lens L6 are close to each other, so that the curvature radius of the curved surfaces on the two sides is limited, the chromatic aberration and the coma aberration of the fisheye lens are reduced, and the imaging quality of the fisheye lens is improved.

The fisheye lens meets the following conditional expression:

0.75＜φ5/φ6＜0.9；

where φ 5 is the outer diameter of the fifth lens L5, φ 6 is the outer diameter of the sixth lens L6.

In this embodiment, the outer diameters of the fifth lens L5 and the sixth lens L6 are limited, so that the chromatic aberration and the coma aberration of the edge position of the fisheye lens are increased, the sensor that can be used by the fisheye lens is also increased, and the application range of the fisheye lens is increased.

The sixth lens L6 satisfies the following conditional expression:

0.1＜D6/TTL＜0.3；

wherein D6 is the thickness of the sixth lens L6.

Through the thickness of the sixth lens L6, the chromatic aberration and the coma aberration of the light at the rear end of the stop STO are reduced, and the imaging quality of the fisheye lens is improved.

The fisheye lens meets the following conditional expression:

Nd1＞1.9；

and/or

Nd3＞1.9；

And/or

Nd5＞1.9；

Wherein Nd1 is a refractive index of the first lens L1, Nd3 is a refractive index of the third lens L3, and Nd5 is a refractive index of the fifth lens L5.

In the embodiment, the field angle of the lens is effectively enlarged, various aberrations of an optical system are reduced, and the distortion and chromatic aberration of the fisheye lens are effectively controlled by limiting the refractive index of each lens.

The fisheye lens meets the following conditional expression:

-3.5＜f1/f＜-2.5；

-3＜f2/f＜-2；

wherein f is a focal length of the fisheye lens, f1 is a focal length of the first lens L1, and f2 is a focal length of the second lens L2.

In the embodiment, the field angle of the fisheye lens is effectively increased by limiting the focal lengths of the first lens L1 and the second lens L2, and the large field angle of the fisheye lens is realized.

Example 2

A fisheye lens comprising, in order from an object plane side to an image plane side:

a first lens L1 of negative power, a second lens L2 of negative power, a third lens L3 of positive power, a stop STO, a fourth lens L4 of positive power, a fifth lens L5 of negative power, a sixth lens L6 of positive power, a filter FI and a protective glass CG, wherein the fourth lens L4 and the fifth lens L5 are cemented.

Table 1 shows basic lens data of the fisheye lens of the present example.

The plane number column indicates the plane number when the number is increased one by one toward the image side with the plane on the object side being the 1 st plane; the surface type column shows the surface type of a certain lens; the radius of curvature of a lens is shown in the column of radius of curvature, positive radius of curvature indicates that the surface is curved in the object side direction, and negative radius of curvature indicates that the surface is curved in the image side direction; the surface spacing on the optical axis of each surface from the surface adjacent to its image side is shown in the center thickness column; the refractive index of a certain lens is shown in the refractive index column; the abbe number of a certain lens is shown in the abbe number column.

[ TABLE 1 ]

Noodle numbering	Surface type	Radius of curvature/mm	Center thickness/mm	Refractive index	Abbe number
						OBJ
S1	Spherical surface	11.307	1.01	2.0509	26.94
						S2	Spherical surface	4.145	2.51
S3	Spherical surface	-285.68	0.6	1.48749	70.45
						S4	Spherical surface	3.066	2
S5	Spherical surface	5.908	2.27	2.00272	19.32
						S6	Spherical surface	353.16	1.25
STO	Spherical surface	INF	0.22
						S8	Spherical surface	-38.014	2.93	1.7725	49.62
S9	Spherical surface	-2.155	0.62	1.98612	16.48
						S10	Spherical surface	-4.653	0.1
S11	Spherical surface	6.486	3.02	1.7725	49.62
						S12	Spherical surface	41.207	2.22
S13	Spherical surface	INF	0.3	1.5168	64.2
						S14	Spherical surface	INF	0.1
S15	Spherical surface	INF	0.55	1.5168	64.2
						S16	Spherical surface	INF	0.3
IMG

In this embodiment, TTL is 20mm, f is 2.15mm, IH is 6mm, IH/TTL is 0.3, and FNO is 1.8;

wherein, TTL is the optical total length of the fisheye lens, IH is the image height of the fisheye lens, and FNO is the f-number of the fisheye lens, and specifically, the fisheye lens of the present embodiment can be applied to a 1/1.8 ″ sensor.

Φ1＝13.85mm，Φ1/TTL＝0.693；

φ5＝5.51mm，φ6＝6.96mm，φ5/φ6＝0.792；

Where Φ 1 is an outer diameter of the first lens L1, Φ 5 is an outer diameter of the fifth lens L5, and Φ 6 is an outer diameter of the sixth lens L6.

D6＝3.02mm，D6/TTL＝0.151；

Wherein D6 is the thickness of the sixth lens L6.

R52＝-4.653mm，R61＝6.486mm，R52/R61＝-0.717；

Wherein R52 is a radius of curvature of the fifth lens L5 on the image plane side, and R61 is a radius of curvature of the sixth lens L6 on the object plane side.

f1＝-6.71mm，f1/f＝-3.13；

f2＝-6.22mm，f2/f＝-2.89；

Wherein f1 is the focal length of the first lens L1, and f2 is the focal length of the second lens L2.

Example 3

A fisheye lens comprising, in order from an object plane side to an image plane side:

a first lens L1 of negative power, a second lens L2 of negative power, a third lens L3 of positive power, a stop STO, a fourth lens L4 of positive power, a fifth lens L5 of negative power, a sixth lens L6 of positive power, a filter FI and a protective glass CG, wherein the fourth lens L4 and the fifth lens L5 are cemented.

Table 2 shows basic lens data of the fisheye lens of the present example.

The plane number column indicates the plane number when the number is increased one by one toward the image side with the plane on the object side being the 1 st plane; the surface type column shows the surface type of a certain lens; the radius of curvature of a lens is shown in the column of radius of curvature, positive radius of curvature indicates that the surface is curved in the object side direction, and negative radius of curvature indicates that the surface is curved in the image side direction; the surface spacing on the optical axis of each surface from the surface adjacent to its image side is shown in the center thickness column; the refractive index of a certain lens is shown in the refractive index column; the abbe number of a certain lens is shown in the abbe number column.

[ TABLE 2 ]

Noodle numbering	Surface type	Radius of curvature/mm	Center thickness/mm	Refractive index	Abbe number
						OBJ
S1	Spherical surface	15.446	2.18	2.0509	26.94
						S2	Spherical surface	4.402	2.93
S3	Spherical surface	-25.55	0.65	1.48749	70.45
						S4	Spherical surface	3.632	2.05
S5	Spherical surface	5.365	1.38	2.00272	19.32
						S6	Spherical surface	-17065	1.94
STO	Spherical surface	INF	0.51
						S8	Spherical surface	-34.855	1.54	1.7725	49.62
S9	Spherical surface	-2.006	1.47	1.98612	16.48
						S10	Spherical surface	-5.24	0.1
S11	Spherical surface	6.621	5.95	1.7725	49.62
						S12	Spherical surface	55.386	0.58
S13	Spherical surface	INF	0.3	1.5168	64.2
						S14	Spherical surface	INF	0.1
S15	Spherical surface	INF	0.55	1.5168	64.2
						S16	Spherical surface	INF	0.3
IMG

In this embodiment, TTL is 22.53mm, f is 2.22mm, IH is 6mm, IH/TTL is 0.266, and FNO is 1.9;

wherein, TTL is the optical total length of the fisheye lens, IH is the image height of the fisheye lens, and FNO is the f-number of the fisheye lens, and specifically, the fisheye lens of the present embodiment can be applied to a 1/1.8 ″ sensor.

Φ1＝16.84mm，Φ1/TTL＝0.747；

φ5＝5.81mm，φ6＝7.34mm，φ5/φ6＝0.792；

Where Φ 1 is an outer diameter of the first lens L1, Φ 5 is an outer diameter of the fifth lens L5, and Φ 6 is an outer diameter of the sixth lens L6.

D6＝5.95mm，D6/TTL＝0.264；

Wherein D6 is the thickness of the sixth lens L6.

R52＝-5.24mm，R61＝6.621mm，R52/R61＝-0.791；

Wherein R52 is a radius of curvature of the fifth lens L5 on the image plane side, and R61 is a radius of curvature of the sixth lens L6 on the object plane side.

f1＝-6.52mm，f1/f＝-2.93；

f2＝-6.48mm，f2/f＝-2.92；

Wherein f1 is the focal length of the first lens L1, and f2 is the focal length of the second lens L2.

Example 4

A fisheye lens comprising, in order from an object plane side to an image plane side:

a first lens L1 of negative power, a second lens L2 of negative power, a third lens L3 of positive power, a stop STO, a fourth lens L4 of positive power, a fifth lens L5 of negative power, a sixth lens L6 of positive power, a filter FI and a protective glass CG, wherein the fourth lens L4 and the fifth lens L5 are cemented.

Table 3 shows basic lens data of the fisheye lens of the present example.

The plane number column indicates the plane number when the number is increased one by one toward the image side with the plane on the object side being the 1 st plane; the surface type column shows the surface type of a certain lens; the radius of curvature of a lens is shown in the column of radius of curvature, positive radius of curvature indicates that the surface is curved in the object side direction, and negative radius of curvature indicates that the surface is curved in the image side direction; the surface spacing on the optical axis of each surface from the surface adjacent to its image side is shown in the center thickness column; the refractive index of a certain lens is shown in the refractive index column; the abbe number of a certain lens is shown in the abbe number column.

[ TABLE 3 ]

In this embodiment, TTL is 22.23mm, f is 2.18mm, IH is 7mm, IH/TTL is 0.315, and FNO is 1.85;

wherein, TTL is the optical total length of the fisheye lens, IH is the image height of the fisheye lens, and FNO is the f-number of the fisheye lens, and specifically, the fisheye lens of the present embodiment can be applied to a 1/1.8 ″ sensor.

Φ1＝15.95mm，Φ1/TTL＝0.717；

φ5＝6.38mm，φ6＝7.34mm，φ5/φ6＝0.869；

Where Φ 1 is an outer diameter of the first lens L1, Φ 5 is an outer diameter of the fifth lens L5, and Φ 6 is an outer diameter of the sixth lens L6.

D6＝3.1mm，D6/TTL＝0.139；

Wherein D6 is the thickness of the sixth lens L6.

R52＝-4.087mm，R61＝7.186mm，R52/R61＝-0.568；

Wherein R52 is a radius of curvature of the fifth lens L5 on the image plane side, and R61 is a radius of curvature of the sixth lens L6 on the object plane side.

f1＝-7.1mm，f1/f＝-3.26；

f2＝-5.36mm，f2/f＝-2.46；

Wherein f1 is the focal length of the first lens L1, and f2 is the focal length of the second lens L2.

Example 5

An image forming apparatus, as shown in fig. 1 to 9, includes: the fisheye lens described in any of the above embodiments, and the imaging element, are configured to receive an image formed by the fisheye lens.

It should be noted that the above embodiments can be freely combined as necessary. The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.