CN112269240A

CN112269240A - Camera lens

Info

Publication number: CN112269240A
Application number: CN202011280972.2A
Authority: CN
Inventors: 杨利全; 金兑映; 王哲
Original assignee: Liaoning Zhonglan Photoelectric Technology Co Ltd
Current assignee: Liaoning Zhonglan Photoelectric Technology Co Ltd
Priority date: 2020-11-16
Filing date: 2020-11-16
Publication date: 2021-01-26

Abstract

The invention relates to an image pickup lens, which comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens which are sequentially arranged from an object side to an image surface along an optical axis, wherein the first lens has positive refractive power, and the object side surface is a convex surface; the fifth lens has positive refractive power, and the image side paraxial region of the fifth lens is a plane; the sixth lens has negative refractive power, the surface of the image side of the sixth lens is a concave surface, and the surfaces of the 6 lenses are all aspheric surfaces; the diaphragm is arranged at the front end of the first lens; and satisfies the following conditional expressions: TTL/ImgH is less than 3.0, and TTL is the total optical length in the camera lens; the imagH is half of the length of the diagonal line of the imaging chip of the camera lens. The camera lens has miniaturization and higher imaging quality.

Description

Camera lens

Technical Field

The invention belongs to the technical field of optical lenses, and relates to a camera lens.

Background

With the development of mobile phones, mobile phones are becoming an increasingly important part of people's daily life, and the quality of the camera function of mobile phones is also becoming a standard for evaluating the performance of mobile phones. In the continuous development of mobile phone lenses, the development of camera lenses using a small number of lenses is gradually shifted to the development of camera lenses using a small number of lenses. The shooting quality of the camera lens is gradually improved along with the increase of the number of the lenses. However, the excessive lenses also bring problems that miniaturization is difficult, the edge field illumination is difficult to improve, and aberrations such as distortion and astigmatism have a large influence on the imaging quality.

Disclosure of Invention

The invention provides a camera lens, which can realize the miniaturization of the lens, improve the marginal illumination of the lens, and improve the influence of distortion and astigmatism on the imaging quality, thereby improving the imaging quality of the lens.

The invention relates to an image pickup lens, which comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens which are sequentially arranged from an object side to an image surface along an optical axis, wherein the first lens has positive refractive power, and the object side surface is a convex surface; the fifth lens has positive refractive power, and the image side paraxial region of the fifth lens is a plane; the sixth lens has negative refractive power, the surface of the image side of the sixth lens is a concave surface, and the surfaces of the 6 lenses are aspheric surfaces; the diaphragm is arranged at the front end of the first lens; and satisfies the following conditional expressions:

TTL/ImgH＜3.0

wherein, TTL is the optical total length in the camera lens; the imagH is half of the length of the diagonal line of the imaging chip of the camera lens.

In the imaging lens of the present invention, the imaging lens further satisfies the following relational expression:

R1/F1<0.7

wherein R1 is the object side radius of the first lens, and F1 is the focal length of the first lens.

In the imaging lens of the present invention, the image-side surface of the first lens element is a convex surface or a concave surface.

-2<(R1-R2)/(R1+R2)<0

wherein R1 is a curvature of an object-side surface of the first lens; r2 is a curvature of an image side surface of the first lens.

In the imaging lens of the present invention, the second lens has negative refractive power.

ET2/CT2<1.45

ET2 is the thickness of the edge of the second lens; CT2 is the optic center thickness of the second lens.

0.7<F5/F<1.0

wherein F5 is the focal length of the fifth lens in the optical system, and F is the focal length of the lens.

-1.3<F6/F<0.8

where F6 is the focal length of the sixth lens element of the optical system, and F is the focal length of the lens.

The camera lens provided by the invention is composed of six plastic lenses, the characteristic of miniaturization can be effectively realized through reasonable arrangement, the edge illumination of the lens is improved, and the influence of distortion and astigmatism on the imaging quality can be improved, so that the imaging quality of the lens is improved.

Drawings

Fig. 1 is a schematic configuration diagram of an imaging lens of embodiment 1;

fig. 2A is a distortion graph of the imaging lens of embodiment 1;

fig. 2B is an astigmatism graph of the imaging lens of embodiment 1;

fig. 2C is a graph of illuminance of the imaging lens of embodiment 1;

fig. 3 is a schematic configuration diagram of an imaging lens of embodiment 2;

fig. 4A is a distortion graph of the imaging lens of embodiment 2;

fig. 4B is an astigmatism graph of the imaging lens of embodiment 2;

fig. 4C is a graph of illuminance of the imaging lens of embodiment 2.

Detailed Description

TTL/ImgH＜3.0

wherein, TTL is the optical total length in the camera lens; the imagH is half of the length of the diagonal line of the imaging chip of the camera lens. The imaging lens satisfying this condition can be miniaturized by appropriately arranging the refractive power of the lens and the position of the lens.

In specific implementation, the camera lens further satisfies the following relational expression:

R1/F1<0.7

wherein R1 is the object side radius of the first lens, and F1 is the focal length of the first lens. The camera lens meeting the condition can improve the influence of distortion on the imaging quality of the lens.

In a specific implementation, the image-side surface of the first lens element is a convex surface or a concave surface, and further satisfies the following relation:

-2<(R1-R2)/(R1+R2)<0

wherein R1 is a curvature of an object-side surface of the first lens; r2 is a curvature of an image side surface of the first lens. Satisfying this condition will reduce the equipment degree of difficulty of camera lens front end lens, can realize the miniaturization to the camera lens.

In specific implementation, the second lens has negative refractive power, and further satisfies the following relational expression:

ET2/CT2<1.45

ET2 is the thickness of the edge of the second lens; CT2 is the optic center thickness of the second lens. The camera lens can improve the transmission route of light rays in the lens after the condition is met, so that the illumination of the marginal field of view can be improved.

0.7<F5/F<1.0

wherein F5 is the focal length of the fifth lens in the optical system, and F is the focal length of the lens. After the condition is met, the astigmatism generated by the camera lens can be improved, and the imaging capability of the camera lens is improved.

-1.3<F6/F<0.8

where F6 is the focal length of the sixth lens element of the optical system, and F is the focal length of the lens. After the condition is met, the astigmatism generated by the camera lens can be further improved, and the imaging capability of the lens is improved.

The first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are even-order aspheric plastic lenses, and aspheric coefficients meet the following equation:

wherein Z is an aspheric sagittal height, c is an aspheric paraxial curvature, y is a lens aperture, k is a conic coefficient, a4 is a 4-th aspheric coefficient, a6 is a 6-th aspheric coefficient, A8 is an 8-th aspheric coefficient, a10 is a 10-th aspheric coefficient, a12 is a 12-th aspheric coefficient, a14 is a 14-th aspheric coefficient, a16 is a 16-th aspheric coefficient, a18 is an 18-th aspheric coefficient, and a20 is a 20-th aspheric coefficient.

Example 1

Fig. 1 is a schematic 2D structure diagram of an imaging lens according to embodiment 1 of the present application.

As shown in fig. 1, the imaging lens of the present embodiment, in order from an object side to an image side along an optical axis, includes: the first lens has a positive refractive power; the second lens has negative refractive power; the third lens has positive refractive power; the fourth lens has negative refractive power, the fifth lens has positive refractive power, and the sixth lens has negative refractive power; the optical filter is provided with an object side surface and an image side surface, and the diaphragm is arranged in front of the first lens. The incident light passes through each lens surface in sequence and is finally imaged on an imaging surface.

Tables 1(a), 1(b) and 1(c) show the surface type, radius of curvature, thickness and material of each lens of the imaging lens of example 1. Wherein the unit of the radius of curvature and the thickness are both millimeters (mm).

The design parameters of the lens assembly of the present embodiment refer to the following table:

TABLE 1(a)

Lens	Surface number	Surface type	Radius of curvature	Thickness of	Material Property (Nd: Vd)
							OBJ	Spherical surface	Inf	Inf
Diaphragm	Stop	Spherical surface	Inf	-0.110
						P1	1	Aspherical surface	2.168	0.474	1.5445.55.987
	2	Aspherical surface	-7.502	0.031
						P2	3	Aspherical surface	9.440	0.23	1.6612.20.354
	4	Aspherical surface	2.929	0.42
						P3	5	Aspherical surface	11.830	0.42	1.5445.55.987
	6	Aspherical surface	-12.737	0.21
						P4	7	Aspherical surface	-3.756	0.26	1.6612.20.354
	8	Aspherical surface	15.781	0.13
						P5	9	Aspherical surface	1.500	0.61	1.5445.55.987
	10	Aspherical surface	Inf	0.31
						P6	11	Aspherical surface	6.824	0.59	1.5445.55.987
	12	Aspherical surface	1.640	0.67
						BK7	13	Spherical surface	Inf	0.21	BK7
	14	Spherical surface	Inf	0.075
						IMA

TABLE 1(b)

In this embodiment, the lens meets the requirements of the above claims, and the specific parameters are shown in the following table:

TABLE 1(c)

According to table 1(a), table 1(b) and fig. 1, the shape of the lens and the attributes of the lens of the current embodiment are clearly shown, which illustrates the feature of the current embodiment that the lens is miniaturized by adjusting the shape and the interval of the lens.

As clearly shown in table 1(c) and fig. 2A, after the lens meets the requirements of the claims, the maximum distortion of the lens is less than 2%, which indicates that the lens can capture high-quality images.

As shown clearly in the astigmatism curves in table 1(c) and fig. 2B, the astigmatism of the lens is relatively small after the lens meets the requirements of the claims, which indicates that the lens is less affected by the astigmatism, and a clear image can be shot. S represents a sagittal direction focus shift amount, and T represents a meridional direction focus shift amount.

As shown clearly in the illumination curves in table 1(C) and fig. 2C, after the lens meets the requirements of the claims, the illumination of the lens edge market is improved, which indicates that the brightness of the image at the edge of the picture is also guaranteed when the lens takes the picture.

It is demonstrated from the above information that the embodiment can realize the miniaturization of the lens, and can reduce the influence of chromatic aberration, distortion and astigmatism, and present a clearer image.

Example 2

Fig. 3 is a 2D configuration diagram of an imaging lens according to embodiment 2 of the present application.

As shown in fig. 3, the imaging lens of the present embodiment, in order from an object side to an image side along an optical axis, includes: the first lens has a positive refractive power; the second lens has negative refractive power; the third lens has positive refractive power; the fourth lens has negative refractive power, the fifth lens has positive refractive power, and the sixth lens has negative refractive power; the optical filter is provided with an object side surface and an image side surface, and the diaphragm is arranged in front of the first lens. The incident light passes through each lens surface in sequence and is finally imaged on an imaging surface.

Tables 2(a), 2(b) and 2(c) show the surface type, radius of curvature, thickness and material of each lens of the optical lens of example 2. Wherein the unit of the radius of curvature and the thickness are both millimeters (mm).

TABLE 2(a)

TABLE 2(b)

In this embodiment, the specific lens parameters are shown in the following table:

TABLE 2(c)

According to table 2(a), table 2(b) and fig. 3, the shape of the lens and the attributes of the lens of the current embodiment are clearly shown, which illustrates the feature of the current embodiment that the lens is miniaturized by adjusting the shape and the interval of the lens.

As clearly shown in table 2(c) and fig. 4A, after the lens meets the requirements of the claims, the maximum distortion of the lens is less than 2%, which indicates that the lens can capture high-quality images.

As shown clearly in the astigmatism curves in table 2(c) and fig. 4B, the astigmatism of the lens is relatively small after the lens meets the requirements of the claims, which indicates that the lens can capture a clear image with less influence of the astigmatism on the lens. S represents a sagittal direction focus shift amount, and T represents a meridional direction focus shift amount.

As shown clearly in the illumination curves in table 2(C) and fig. 4C, after the lens meets the requirements of the claims, the illumination of the lens edge market is improved, which indicates that the brightness of the image at the edge of the picture is also guaranteed when the lens takes the picture.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the scope of the present invention, which is defined by the appended claims.

Claims

1. An imaging lens includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens arranged in this order from an object side to an image plane along an optical axis, characterized in that:

the first lens has positive refractive power, and the object side surface is a convex surface; the fifth lens has positive refractive power, and the image side paraxial region of the fifth lens is a plane; the sixth lens has negative refractive power, the surface of the image side of the sixth lens is a concave surface, and the surfaces of the 6 lenses are aspheric surfaces; the diaphragm is arranged at the front end of the first lens; and satisfies the following conditional expressions:

TTL/ImgH＜3.0

2. An imaging lens according to claim 1, wherein the imaging lens further satisfies the following relation:

R1/F1<0.7

3. The imaging lens according to claim 1, wherein an image side surface of the first lens element is a convex surface or a concave surface.

4. An imaging lens according to claim 1, wherein the imaging lens further satisfies the following relation:

-2<(R1-R2)/(R1+R2)<0

5. A camera lens according to claim 1, wherein the second lens has a negative refractive power.

6. An imaging lens according to claim 1, wherein the imaging lens further satisfies the following relation:

ET2/CT2<1.45

7. An imaging lens according to claim 1, wherein the imaging lens further satisfies the following relation:

0.7<F5/F<1.0

8. An imaging lens according to claim 1, wherein the imaging lens further satisfies the following relation:

-1.3<F6/F<0.8