CN111638584A

CN111638584A - Optical assembly, camera module and mobile terminal

Info

Publication number: CN111638584A
Application number: CN201910155172.9A
Authority: CN
Inventors: 谢晗; 邹海荣; 刘彬彬
Original assignee: OFilm Tech Co Ltd
Current assignee: Nanchang OFilm Precision Optical Products Co Ltd; OFilm Group Co Ltd
Priority date: 2019-03-01
Filing date: 2019-03-01
Publication date: 2020-09-08

Abstract

The invention relates to an optical assembly, a camera module and a mobile terminal. The optical assembly sequentially comprises a first lens with positive refractive power from an object side to an image side, wherein 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; a second lens element with positive refractive power having a convex object-side surface at an optical axis; a third lens element with negative refractive power having a concave object-side surface and a convex image-side surface; a fourth lens; a fifth lens; the object side surface and the image side surface of the sixth lens are both aspheric surfaces; the image side surface of the seventh lens element is concave at the optical axis and has at least one inflection point; the optical component satisfies f/EPD < 2.00; f is the total effective focal length of the optical assembly and EPD is the entrance pupil diameter of the optical assembly. When the above relation is satisfied, the optical assembly has the characteristic of large light flux, thereby improving the imaging quality in an environment with insufficient light.

Description

Optical assembly, camera module and mobile terminal

Technical Field

The invention relates to the field of optical imaging, in particular to an optical assembly, a camera module and a mobile terminal.

Background

With the development of portable electronic products such as smart phones and tablet computers, the requirements of the market for the imaging quality of the camera lens on the portable electronic products are gradually increased. Among these, the photosensitive elements commonly used for acquiring images are typically both Charge Coupled Devices (CCD) or complementary metal oxide semiconductor sensors (CMOS). However, in general, the image quality of the photosensitive element is significantly degraded in environments with insufficient light, such as dusk and rainy days. Therefore, a large-aperture camera lens is urgently needed to increase the light flux and improve the imaging quality in the environment with insufficient light.

Disclosure of Invention

Accordingly, it is desirable to provide an optical assembly, an image pickup module and a mobile terminal, which are directed to the problem of how to provide an image pickup lens with a large aperture.

An optical assembly comprising, in order from an object side to an image side:

the optical lens assembly comprises a first lens element with positive refractive power, a second lens element with positive refractive power, a third lens element with negative refractive power, a fourth lens element with positive refractive power, a fifth lens element with negative refractive power, a sixth lens element with positive refractive power, a sixth lens element;

a second lens element with positive refractive power having a convex object-side surface at an optical axis;

a third lens element with negative refractive power having a concave object-side surface and a convex image-side surface;

a fourth lens element with refractive power;

a fifth lens element with refractive power;

the sixth lens element with refractive power has an object-side surface and an image-side surface which are both aspheric;

the image side surface of the seventh lens element is concave on the optical axis, and at least one inflection point exists on the image side surface of the seventh lens element;

the optical assembly satisfies the following relationship:

f/EPD＜2.00；

where f is the total effective focal length of the optical assembly and EPD is the entrance pupil diameter of the optical assembly.

When the f/EPD relation is satisfied, under the same specification of the total effective focal length, the optical assembly has a larger entrance pupil diameter (clear aperture) to have the characteristic of large light transmission amount, so that the imaging quality in environments with insufficient light such as dusk and rainy days is improved. In addition, because the optical assembly has a larger entrance pupil diameter, the effective half aperture of the object side surface of the first lens is correspondingly enlarged, so that the optical assembly has larger light transmission quantity.

In one embodiment, the optical assembly satisfies the following relationship:

-1.00＜f12/f34＜0；

wherein f12 is a composite focal length of the first lens and the second lens, and f34 is a composite focal length of the third lens and the fourth lens. Since the light-entering amount of the optical assembly is large, it is necessary to reasonably optimize the positive refractive power of the first lens element and the second lens element to focus light, and at this time, if the first lens element and the second lens element are configured with weaker positive refractive power, it is not favorable to compress the dimension of the optical assembly in the optical axis direction, so that the size of the optical assembly is large; if the first lens element and the second lens element are configured with a strong positive refractive power, the deflection angle of the light passing through the first lens element and the second lens element is increased, so that the sensitivity of the optical assembly is increased, and the actual mass production is unstable. In addition, the positive refractive power lens also generates spherical aberration on the optical element, which affects the imaging quality. Because the first lens element and the second lens element can form a lens assembly with positive refractive power, when the above relationship is satisfied, the third lens element and the fourth lens element can form a lens assembly with negative refractive power, and simultaneously, the refractive powers of the two lens assemblies can be reasonably configured to balance the chromatic aberration, thereby improving the imaging quality. When the ratio relation is lower than the lower limit, the negative refractive power of the lens group formed by the third lens element and the fourth lens element is too strong, so that high-order aberration is easily generated, and the imaging quality is affected.

In one embodiment, the optical assembly satisfies the following relationship:

0.35＜Y32/Y72＜0.50；

wherein Y32 is a maximum effective radius of an image-side surface of the third lens, and Y72 is a maximum effective radius of an image-side surface of the seventh lens. When the relationship is met, the aperture of the image side surface of the third lens and the aperture of the image side surface of the seventh lens can be reasonably adjusted, so that the incident angle and the emergent angle of marginal light rays in the seventh lens cannot be excessively increased, the matching of the optical assembly and the photosensitive chip is facilitated, and the higher imaging quality is ensured. When the ratio is lower than the lower limit, the aperture of the image side surface of the seventh lens is larger, and marginal rays are easily blocked by the imaging module mechanism, so that the relative illumination of an off-axis field of view is reduced; when the ratio is larger than the upper limit, the aperture of the image side surface of the third lens is increased, which is not favorable for miniaturization design.

In one embodiment, the optical assembly satisfies the following relationship:

-1.50＜f/f7＜0；

wherein f7 is the focal length of the seventh lens. The image side surface of the seventh lens has at least one point of inflection, so that the capacity of eliminating off-axis field distortion is realized. When the relation is satisfied, when the light passes through the optical assembly and is imaged on the photosensitive chip, the phenomenon that the quality of the off-axis view field image is reduced due to the fact that the angle of the edge light entering the imaging surface is too large can be effectively inhibited. When the ratio is lower than the lower limit, the negative refractive power of the seventh lens element is too large, resulting in an increase in higher-order aberrations.

In one embodiment, the optical assembly satisfies the following relationship:

0＜f1/f＜3.10；

wherein f1 is the focal length of the first lens. When the relation is satisfied, the focal length of the first lens and the total effective focal length of the optical assembly can be reasonably configured, so that the optical assembly has better capacity of balancing field curvature to improve imaging quality.

In one embodiment, the optical assembly satisfies the following relationship:

0.50＜R12/R21＜1.00；

wherein R12 is a curvature radius of the image side surface of the first lens at the optical axis, and R21 is a curvature radius of the object side surface of the second lens at the optical axis. Because the image side surface of the first lens is a concave surface and the object side surface of the second lens is a convex surface at the optical axis, when the above relation is satisfied, the image side surface of the first lens is close to the surface type of the object side surface of the second lens, thereby avoiding excessive deflection of light passing through the image side surface of the first lens and the object side surface of the second lens, and simultaneously, reducing the sensitivity of the optical assembly and improving the imaging quality of the optical assembly.

In one embodiment, the optical assembly satisfies the following relationship:

TTL/ImgH＜1.60；

wherein, TTL is a distance on an optical axis from an object-side surface of the first lens element to an imaging surface of the optical element, and ImgH is a half of a diagonal length of an effective pixel area of the optical element on the imaging surface. When the above relation is satisfied, the length of the optical component in the optical axis direction can be effectively compressed, thereby realizing the miniaturization design.

In one embodiment, the optical assembly satisfies the following relationship:

3.00＜(CT1+CT2)/CT3＜5.00；

wherein CT1 is the thickness of the first lens element on the optical axis, CT2 is the thickness of the second lens element on the optical axis, and CT3 is the thickness of the third lens element on the optical axis. When the above relation is satisfied, the thicknesses of the first lens, the second lens and the third lens can be optimized, and the mold processing precision and the manufacturability of the third lens forming can be considered when the length of the optical assembly in the optical axis direction is shortened, so that the optical assembly is suitable for mass production. When the ratio is lower than the lower limit, the thickness of the third lens on the optical axis is too thin, so that the forming difficulty of the third lens is increased, and the lens is easy to have bad phenomena such as bonding lines, unsaturation and the like; when the ratio is higher than the upper limit, the thicknesses of the first lens element and the second lens element on the optical axis are too thick, which is not favorable for shortening the length of the optical assembly in the optical axis direction, i.e., is not favorable for miniaturization.

In one embodiment, the optical assembly satisfies the following relationship:

0.20＜(T45+T56)/T67＜1.20；

wherein T45 is an axial distance between the fourth lens element and the fifth lens element, T56 is an axial distance between the fifth lens element and the sixth lens element, and T67 is an axial distance between the sixth lens element and the seventh lens element. When the above relation is satisfied, the distance between the fourth lens and the fifth lens, the distance between the fifth lens and the sixth lens, and the distance between the sixth lens and the seventh lens can be reasonably optimized, so that the length of the optical assembly in the optical axis direction is effectively compressed, and the miniaturization design is realized.

In one embodiment, the optical assembly further comprises an aperture disposed on the object side of the first lens or between the first lens and the second lens.

A camera module, comprising a photosensitive element and the optical assembly of any of the above embodiments, wherein the photosensitive element is disposed on an image side of the optical assembly.

A mobile terminal comprises the camera module in the embodiment.

Drawings

FIG. 1 is a schematic view of an optical assembly according to a first embodiment of the present invention;

fig. 2 is a spherical aberration diagram (mm), an astigmatism diagram (mm), and a distortion diagram (%);

FIG. 3 is a schematic view of an optical assembly according to a second embodiment of the present invention;

FIG. 4 is a spherical aberration diagram (mm), an astigmatism diagram (mm) and a distortion diagram (%);

FIG. 5 is a schematic view of an optical assembly according to a third embodiment of the present invention;

FIG. 6 is a spherical aberration diagram (mm), an astigmatism diagram (mm) and a distortion diagram (%) -of the optical assembly in the third embodiment;

FIG. 7 is a schematic view of an optical assembly according to a fourth embodiment of the present invention;

FIG. 8 is a spherical aberration diagram (mm), an astigmatism diagram (mm) and a distortion diagram (%);

FIG. 9 is a schematic view of an optical assembly provided in a fifth embodiment of the present invention;

fig. 10 is a spherical aberration diagram (mm), an astigmatism diagram (mm), and a distortion diagram (%);

FIG. 11 is a schematic view of an optical assembly according to a sixth embodiment of the present invention;

fig. 12 is a spherical aberration diagram (mm), an astigmatism diagram (mm), and a distortion diagram (%) -of the optical assembly in the sixth embodiment;

FIG. 13 is a schematic view of an optical assembly according to a seventh embodiment of the present invention;

fig. 14 is a spherical aberration diagram (mm), an astigmatism diagram (mm), and a distortion diagram (%) -of the optical assembly in the seventh embodiment;

fig. 15 is a schematic view of a camera module according to an embodiment of the present invention;

fig. 16 is a schematic diagram of a mobile terminal according to an embodiment of the present invention.

Detailed Description

To facilitate an understanding of the invention, the invention will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. In contrast, when an element is referred to as being "directly on" another element, there are no intervening elements present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Referring to fig. 1, the optical assembly 10 in the embodiment of the present application includes, in order from an object side to an image side, a first lens element L1 with positive refractive power, a second lens element L2 with positive refractive power, a third lens element L3 with negative refractive power, a fourth lens element L4 with refractive power, a fifth lens element L5 with refractive power, a sixth lens element L6 with refractive power, and a seventh lens element L7 with negative refractive power.

The first lens L1 includes an object side surface S2 and an image side surface S3, the second lens L2 includes an object side surface S4 and an image side surface S5, the third lens L3 includes an object side surface S6 and an image side surface S7, the fourth lens L4 includes an object side surface S8 and an image side surface S9, the fifth lens L5 includes an object side surface S10 and an image side surface S11, the sixth lens L6 includes an object side surface S12 and an image side surface S13, and the seventh lens L7 includes an object side surface S14 and an image side surface S15.

Specifically, the object-side surface S2 of the first lens element L1 is convex, and the image-side surface S3 of the first lens element L1 is concave; the object-side surface S4 of the second lens L2 is convex at the optical axis; the object-side surface S6 of the third lens element L3 is concave along the optical axis, and the image-side surface S7 of the third lens element L3 is convex along the optical axis; the object-side surface S12 and the image-side surface S13 of the sixth lens element L6 are aspheric; the image-side surface S15 of the seventh lens L7 is concave at the optical axis, and the image-side surface S15 has at least one inflection point. In addition, the optical unit 10 further includes an image forming surface S18 located on an image side of the seventh lens L7.

The light carrying the information of the object to be measured sequentially passes through the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6 and the seventh lens L7, and finally reaches the image plane S18.

The aspheric surface type formulas of the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6 and the seventh lens L7 are as follows:

wherein Z is a distance from a corresponding point on the aspherical surface to a plane tangent to the surface vertex, r is a distance from a corresponding point on the aspherical surface to the optical axis, c is a curvature of the aspherical surface vertex, k is a conic constant, and Ai is a coefficient corresponding to the i-th high-order term in the aspherical surface type formula.

In some embodiments, the optical assembly 10 further includes a stop ST0 disposed on an object side of the first lens L1. Preferably, the stop ST0 is fixedly disposed on the object side surface S2 of the first lens L1, so that the length of the optical module 10 in the optical axis direction can be reduced, and a compact design can be achieved. By providing the stop ST0 on the object side of the first lens L1, the exit pupil can be made distant from the imaging plane, and the effective diameter of the optical assembly 10 can be reduced without reducing the telecentricity of the optical assembly 10, thereby achieving downsizing.

In other embodiments, the stop ST0 may also be disposed between the first lens L1 and the second lens L2.

In some embodiments, the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6 and the seventh lens L7 are all made of plastic, and in this case, the plastic lens can reduce the weight of the optical assembly 10 and reduce the production cost. In some embodiments, the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6 and the seventh lens L7 are made of glass, and thus the optical assembly 10 can endure higher temperature and has better optical performance. In other embodiments, only the first lens L1 may be made of glass, and the other lenses may be made of plastic, in which case, the first lens L1 closest to the object side can better withstand the influence of the ambient temperature on the object side, and the other lenses are made of plastic, so that the production cost of the optical assembly 10 is kept low.

In some embodiments, the optical assembly 10 is disposed with the infrared filter 110 made of glass, and the infrared filter 110 is disposed on the image side of the seventh lens element L7. The infrared filter 110 includes an object side S16 and an image side S17. The infrared filter 110 is used for filtering the light rays for imaging, and is specifically used for isolating infrared light to prevent the infrared light from reaching the imaging surface S18, thereby preventing the infrared light from affecting the color and the definition of a normal image and improving the imaging quality of the optical assembly 10.

In some embodiments, the optical assembly 10 satisfies the following relationship:

f/EPD＜2.00；

where f is the total effective focal length of the optical assembly 10 and EPD is the entrance pupil diameter of the optical assembly 10. In some embodiments, the f/EPD relationship may be 1.42, 1.52, 1.64, 1.72, 1.82, or 1.92.

When the above-mentioned f/EPD relationship is satisfied, under the same specification of the total effective focal length, the optical element 10 has a larger entrance pupil diameter (clear aperture) to have the characteristic of a large light transmission amount, thereby improving the imaging quality in environments with insufficient light such as dusk and rainy days. In addition, since the optical assembly 10 has a larger entrance pupil diameter, the effective half aperture of the object-side surface S2 of the first lens L1 is correspondingly enlarged, so that the optical assembly 10 has a larger light flux.

In some of these embodiments, the optical assembly 10 satisfies the following relationship:

-1.00＜f12/f34＜0；

where f12 is a composite focal length of the first lens L1 and the second lens L2, and f34 is a composite focal length of the third lens L3 and the fourth lens L4. In some embodiments, the relationship of f12/f34 can be-0.36, -0.30, -0.28, -0.20, -0.10, or-0.05. Since the light entering amount of the optical device 10 is large, it is necessary to reasonably optimize the positive refractive power of the first lens element L1 and the second lens element L2 to focus the light, and at this time, if the first lens element L1 and the second lens element L2 are configured with weak positive refractive power, it is not favorable to compress the size of the optical device 10 in the optical axis direction, so that the size of the optical device 10 is large; if the first lens element L1 and the second lens element L2 have strong positive refractive power, the deflection angle of the light passing through the first lens element L1 and the second lens element L2 is increased, and the sensitivity of the optical assembly 10 is increased, thereby making the actual mass production unstable. In addition, the positive refractive power lens also generates spherical aberration in the optical assembly 10, which affects the imaging quality. Since the first lens element L1 and the second lens element L2 can form a lens assembly with positive refractive power, when the above relationship is satisfied, the third lens element L3 and the fourth lens element L4 can form a lens assembly with negative refractive power, and at the same time, the refractive powers of the two lens assemblies can be reasonably configured to balance the chromatic aberration, thereby improving the imaging quality. When the ratio is lower than the lower limit, the negative refractive power of the lens assembly formed by the third lens element L3 and the fourth lens element L4 is too strong, so that high-order aberration is easily generated, and the imaging quality is affected.

0.35＜Y32/Y72＜0.50；

here, Y32 is the maximum effective radius of the image-side surface S7 of the third lens L3, and Y72 is the maximum effective radius of the image-side surface S15 of the seventh lens L7. In some embodiments, the relationship of Y32/Y72 may be 0.37, 0.40, 0.43, 0.45, or 0.47. When the above relationship is satisfied, the aperture of the image-side surface S7 of the third lens L3 and the aperture of the image-side surface S15 of the seventh lens L7 can be reasonably adjusted, so that the incident angle and the exit angle of the marginal ray in the seventh lens L7 are not excessively increased, thereby facilitating the matching of the optical assembly 10 with the photosensitive chip and ensuring higher imaging quality. When the ratio is lower than the lower limit, the aperture of the image side surface S15 of the seventh lens L7 is larger, and marginal rays are easily blocked by the imaging module mechanism, so that the relative illumination of an off-axis field of view is reduced; when the ratio is larger than the upper limit, the aperture of the image-side surface S7 of the third lens L3 increases, which is disadvantageous for the compact design.

-1.50＜f/f7＜0；

where f7 is the focal length of the seventh lens L7. The image side S15 of the seventh lens L7 has at least one point of inflection that provides the ability to eliminate off-axis field distortion. In some embodiments, the relationship of f/f7 may be-1.00, -0.90, -0.80, -0.70, -0.60, or-0.35. When the above relationship is satisfied, when the light passes through the optical assembly 10 and is imaged on the photosensitive chip, the phenomenon that the off-axis view image quality is reduced due to the fact that the angle of the marginal light incident on the imaging surface S18 is too large can be effectively inhibited. When the ratio is lower than the lower limit, the negative refractive power of the seventh lens element L7 is too large, resulting in an increase in higher-order aberrations.

0＜f1/f＜3.10；

where f1 is the focal length of the first lens L1. In some embodiments, the relationship of f1/f may be 1.70, 2.00, 2.20, 2.30, 2.70, 2.80, 2.90, or 3.00. When the above relationship is satisfied, the focal length of the first lens L1 and the total effective focal length of the optical assembly 10 can be configured reasonably, so that the optical assembly 10 has a better ability of balancing curvature of field to improve the imaging quality.

0.50＜R12/R21＜1.00；

wherein R12 is the radius of curvature of the image-side surface S3 of the first lens L1 at the optical axis, and R21 is the radius of curvature of the object-side surface S4 of the second lens L2 at the optical axis. In some embodiments, the relationship of R12/R21 may be 0.67, 0.77, 0.80, 0.87, or 0.94. Since the image-side surface S3 of the first lens element L1 is concave and the object-side surface S4 of the second lens element L2 is convex along the optical axis, when the above relationship is satisfied, the image-side surface S3 of the first lens element L1 and the object-side surface S4 of the second lens element L2 can be made to have a similar surface shape, so that excessive deflection of light rays passing through the image-side surface S3 of the first lens element L1 and the object-side surface S4 of the second lens element L2 can be avoided, and at the same time, the sensitivity of the optical assembly 10 can be reduced and the imaging quality of the optical assembly 10 can be improved.

TTL/ImgH＜1.60；

wherein, TTL is an axial distance from the object-side surface S2 of the first lens element L1 to the image plane S18 of the optical device 10, and ImgH is a half of a diagonal length of an effective pixel area of the optical device 10 on the image plane S18. In some embodiments, the TTL/ImgH relationship may be 1.44, 1.50, 1.51, 1.54, or 1.56. When the above relationship is satisfied, the length of the optical element 10 in the optical axis direction can be effectively compressed, thereby realizing a miniaturized design.

3.00＜(CT1+CT2)/CT3＜5.00；

wherein CT1 is the thickness of the first lens element L1 on the optical axis, CT2 is the thickness of the second lens element L2 on the optical axis, and CT3 is the thickness of the third lens element L3 on the optical axis. In some embodiments, the relationship of (CT1+ CT2)/CT3 may be 3.70, 4.10, 4.20, 4.40, 4.70, or 4.80. When the above relationship is satisfied, the thicknesses of the first lens L1, the second lens L2, and the third lens L3 can be optimized, and manufacturability of production and molding of the third lens L3 can be considered while the length of the optical element 10 in the optical axis direction is shortened, thereby simplifying the manufacturing process. When the ratio is lower than the lower limit, the thickness of the third lens L3 on the optical axis will be too thin, which results in increased difficulty in molding the third lens L3 and higher sensitivity; when the ratio is higher than the upper limit, the thicknesses of the first lens element L1 and the second lens element L2 on the optical axis are too thick, which is not favorable for shortening the length of the optical assembly 10 on the optical axis, i.e., is unfavorable for miniaturization.

0.20＜(T45+T56)/T67＜1.20；

t45 is the distance on the optical axis between the fourth lens L4 and the fifth lens L5, T56 is the distance on the optical axis between the fifth lens L5 and the sixth lens L6, and T67 is the distance on the optical axis between the sixth lens L6 and the seventh lens L7. In some embodiments, the relationship of (T45+ T56)/T67 may be 0.40, 0.55, 0.60, 0.75, 0.80, 0.90, 1.00, or 1.10. When the above relationship is satisfied, the distance between the fourth lens L4 and the fifth lens L5, the distance between the fifth lens L5 and the sixth lens L6, and the distance between the sixth lens L6 and the seventh lens L7 can be optimized reasonably, so as to effectively compress the length of the optical assembly 10 in the optical axis direction, thereby realizing a compact design.

First embodiment

In the first embodiment shown in fig. 1, the optical assembly 10 includes, in order from an object side to an image side, a stop ST0, a first lens element L1 with positive refractive power, a second lens element L2 with positive refractive power, a third lens element L3 with negative refractive power, a fourth lens element L4 with negative refractive power, a fifth lens element L5 with positive refractive power, a sixth lens element L6 with negative refractive power, a seventh lens element L7 with negative refractive power, and an infrared filter 110. Fig. 2 is a spherical aberration diagram (mm), an astigmatism diagram (mm) and a distortion diagram (%) of the optical assembly 10 in the first embodiment, wherein the astigmatism diagram and the distortion diagram are data diagrams at a reference wavelength.

The object-side surface S2 of the first lens element L1 is convex along the optical axis, and the image-side surface S3 of the first lens element L1 is concave along the optical axis; the object-side surface S2 of the first lens element L1 is convex at the circumference, and the image-side surface S3 of the first lens element L1 is concave at the circumference. The object-side surface S4 of the second lens element L2 is convex along the optical axis, and the image-side surface S5 of the second lens element L2 is convex along the optical axis; the object-side surface S4 of the second lens element L2 is convex at the circumference, and the image-side surface S5 of the second lens element L2 is convex at the circumference. The object-side surface S6 of the third lens element L3 is concave along the optical axis, and the image-side surface S7 of the third lens element L3 is convex along the optical axis; the object-side surface S6 of the third lens element L3 is concave at the circumference, and the image-side surface S7 of the third lens element L3 is convex at the circumference. The object-side surface S8 of the fourth lens element L4 is convex along the optical axis, and the image-side surface S9 of the fourth lens element L4 is concave along the optical axis; the object-side surface S8 of the fourth lens element L4 is concave at the circumference, and the image-side surface S9 of the fourth lens element L4 is convex at the circumference. The object-side surface S10 of the fifth lens element L5 is concave along the optical axis, and the image-side surface S11 of the fifth lens element L5 is convex along the optical axis; the object-side surface S10 of the fifth lens element L5 is concave at the circumference, and the image-side surface S11 of the fifth lens element L5 is convex at the circumference. The object-side surface S12 of the sixth lens element L6 is convex along the optical axis, and the image-side surface S13 of the sixth lens element L6 is concave along the optical axis; the object-side surface S12 of the sixth lens element L6 is concave at the circumference, and the image-side surface S13 of the sixth lens element L6 is convex at the circumference. The object-side surface S14 of the seventh lens element L7 is convex along the optical axis, and the image-side surface S15 of the seventh lens element L7 is concave along the optical axis; the object-side surface S14 of the seventh lens element L7 is concave at the circumference, and the image-side surface S15 of the seventh lens element L7 is convex at the circumference.

The object-side surface and the image-side surface of the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6 and the seventh lens L7 are aspheric.

The first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, and the seventh lens L7 are all made of plastic.

Specifically, the optical assembly 10 satisfies the following relationship:

f/EPD＝1.50；

where f is the total effective focal length of the optical assembly 10 and EPD is the entrance pupil diameter of the optical assembly 10. When the above-mentioned f/EPD relationship is satisfied, under the same specification of the total effective focal length, the optical element 10 has a larger entrance pupil diameter (clear aperture) to have the characteristic of a large light transmission amount, thereby improving the imaging quality in environments with insufficient light such as dusk and rainy days. In addition, since the optical assembly 10 has a larger entrance pupil diameter, the effective half aperture of the object-side surface S2 of the first lens L1 is correspondingly enlarged, so that the optical assembly 10 has a larger light flux.

The optical assembly 10 satisfies the following relationship:

f12/f34＝-0.24；

where f12 is a composite focal length of the first lens L1 and the second lens L2, and f34 is a composite focal length of the third lens L3 and the fourth lens L4. Since the light entering amount of the optical device 10 is large, it is necessary to reasonably optimize the positive refractive power of the first lens element L1 and the second lens element L2 to focus the light, and at this time, if the first lens element L1 and the second lens element L2 are configured with weak positive refractive power, it is not favorable to compress the size of the optical device 10 in the optical axis direction, so that the size of the optical device 10 is large; if the first lens element L1 and the second lens element L2 have strong positive refractive power, the deflection angle of the light passing through the first lens element L1 and the second lens element L2 is increased, and the sensitivity of the optical assembly 10 is increased, thereby making the actual mass production unstable. In addition, the positive refractive power lens also generates spherical aberration in the optical assembly 10, which affects the imaging quality. Since the first lens element L1 and the second lens element L2 can form a lens assembly with positive refractive power, when the above relationship is satisfied, the third lens element L3 and the fourth lens element L4 can form a lens assembly with negative refractive power, and at the same time, the refractive powers of the two lens assemblies can be reasonably configured to balance the chromatic aberration, thereby improving the imaging quality.

The optical assembly 10 satisfies the following relationship:

Y32/Y72＝0.42；

here, Y32 is the maximum effective radius of the image-side surface S7 of the third lens L3, and Y72 is the maximum effective radius of the image-side surface S15 of the seventh lens L7. When the above relationship is satisfied, the aperture of the image-side surface S7 of the third lens L3 and the aperture of the image-side surface S15 of the seventh lens L7 can be reasonably adjusted, so that the incident angle and the exit angle of the marginal ray in the seventh lens L7 are not excessively increased, thereby facilitating the matching of the optical assembly 10 with the photosensitive chip and ensuring higher imaging quality.

The optical assembly 10 satisfies the following relationship:

f/f7＝-0.31；

where f7 is the focal length of the seventh lens L7. The image side S15 of the seventh lens L7 has at least one point of inflection that provides the ability to eliminate off-axis field distortion. When the above relationship is satisfied, when the light passes through the optical assembly 10 and is imaged on the photosensitive chip, the phenomenon that the off-axis view image quality is reduced due to the fact that the angle of the marginal light incident on the imaging surface S18 is too large can be effectively inhibited.

The optical assembly 10 satisfies the following relationship:

f1/f＝2.17；

where f1 is the focal length of the first lens L1. When the above relationship is satisfied, the focal length of the first lens L1 and the total effective focal length of the optical assembly 10 can be configured reasonably, so that the optical assembly 10 has a better ability of balancing curvature of field to improve the imaging quality.

The optical assembly 10 satisfies the following relationship:

R12/R21＝0.63；

wherein R12 is the radius of curvature of the image-side surface S3 of the first lens L1 at the optical axis, and R21 is the radius of curvature of the object-side surface S4 of the second lens L2 at the optical axis. Since the image-side surface S3 of the first lens element L1 is concave and the object-side surface S4 of the second lens element L2 is convex along the optical axis, when the above relationship is satisfied, the image-side surface S3 of the first lens element L1 and the object-side surface S4 of the second lens element L2 can be made to have a similar surface shape, so that excessive deflection of light rays passing through the image-side surface S3 of the first lens element L1 and the object-side surface S4 of the second lens element L2 can be avoided, and at the same time, the sensitivity of the optical assembly 10 can be reduced and the imaging quality of the optical assembly 10 can be improved.

The optical assembly 10 satisfies the following relationship:

TTL/ImgH＝1.52；

wherein, TTL is an axial distance from the object-side surface S2 of the first lens element L1 to the image plane S18 of the optical device 10, and ImgH is a half of a diagonal length of an effective pixel area of the optical device 10 on the image plane S18. When the above relationship is satisfied, the length of the optical element 10 in the optical axis direction can be effectively compressed, thereby realizing a miniaturized design.

The optical assembly 10 satisfies the following relationship:

(CT1+CT2)/CT3＝4.68；

wherein CT1 is the thickness of the first lens element L1 on the optical axis, CT2 is the thickness of the second lens element L2 on the optical axis, and CT3 is the thickness of the third lens element L3 on the optical axis. When the above relationship is satisfied, the thicknesses of the first lens L1, the second lens L2, and the third lens L3 can be optimized, and manufacturability of production and molding of the third lens L3 can be considered while the length of the optical element 10 in the optical axis direction is shortened, thereby simplifying the manufacturing process.

The optical assembly 10 satisfies the following relationship:

(T45+T56)/T67＝1.16；

t45 is the distance on the optical axis between the fourth lens L4 and the fifth lens L5, T56 is the distance on the optical axis between the fifth lens L5 and the sixth lens L6, and T67 is the distance on the optical axis between the sixth lens L6 and the seventh lens L7. When the above relationship is satisfied, the distance between the fourth lens L4 and the fifth lens L5, the distance between the fifth lens L5 and the sixth lens L6, and the distance between the sixth lens L6 and the seventh lens L7 can be optimized reasonably, so as to effectively compress the length of the optical assembly 10 in the optical axis direction, thereby realizing a compact design.

In the first embodiment, the total effective focal length f of the optical assembly 10 is 4.07mm, the aperture value FNO is 1.50, the maximum field angle FOV is 82.5 degrees (deg.), and the distance TTL from the object-side surface S2 of the first lens L1 to the image plane S18 on the optical axis is 5.50 mm.

In addition, the respective parameters of the optical assembly 10 are given by table 1 and table 2. The elements from the object plane to the image plane S18 were arranged in the order of the elements from top to bottom in table 1. The surface numbers 2 and 3 are the object-side surface S2 and the image-side surface S3 of the first lens L1, respectively, that is, the surface with the smaller surface number is the object-side surface and the surface with the larger surface number is the image-side surface in the same lens. The Y radius in table 1 is the radius of curvature of the object-side surface or the image-side surface of the corresponding surface number at the optical axis. The numerical value of the stop ST0 in the "thickness" parameter column is the distance on the optical axis from the stop ST0 to the vertex of the object-side surface of the subsequent lens (the vertex refers to the intersection point of the lens and the optical axis), the direction from the object-side surface of the first lens to the image-side surface of the last lens is the positive direction of the optical axis by default, when the value is negative, it indicates that the stop ST0 is disposed on the right side of the vertex of the object-side surface S2 of the first lens L1, and if the thickness of the stop STO is positive, the stop is on the left side of the vertex of the object-side surface of the first. The first value in the "thickness" parameter column of the first lens element L1 is the thickness of the lens element on the optical axis, and the second value is the distance from the image-side surface of the lens element to the stop, the IR filter 110 or the object-side surface of the subsequent lens element on the optical axis. The numerical value corresponding to the larger surface number of the infrared filter 110 in the "thickness" parameter is the distance from the image side surface S17 to the image plane S18 of the infrared filter 110. Table 2 is a table of relevant parameters of the aspherical surface of each lens in table 1, where K is a conic constant and Ai is a coefficient corresponding to the i-th high-order term in the aspherical surface type formula.

In the following examples, the refractive index and abbe number of each lens are both numerical values at a reference wavelength.

TABLE 1

TABLE 2

Second embodiment

In the second embodiment as shown in fig. 3, the optical assembly 10 includes, in order from an object side to an image side, a stop ST0, a first lens element L1 with positive refractive power, a second lens element L2 with positive refractive power, a third lens element L3 with negative refractive power, a fourth lens element L4 with negative refractive power, a fifth lens element L5 with positive refractive power, a sixth lens element L6 with positive refractive power, a seventh lens element L7 with negative refractive power, and an infrared filter 110. Fig. 4 is a spherical aberration diagram (mm), an astigmatism diagram (mm) and a distortion diagram (%) of the optical assembly 10 in the second embodiment, wherein the astigmatism diagram and the distortion diagram are data diagrams at a reference wavelength.

The object-side surface S2 of the first lens element L1 is convex along the optical axis, and the image-side surface S3 of the first lens element L1 is concave along the optical axis; the object-side surface S2 of the first lens element L1 is convex at the circumference, and the image-side surface S3 of the first lens element L1 is concave at the circumference. The object-side surface S4 of the second lens element L2 is convex along the optical axis, and the image-side surface S5 of the second lens element L2 is concave along the optical axis; the object-side surface S4 of the second lens element L2 is convex at the circumference, and the image-side surface S5 of the second lens element L2 is convex at the circumference. The object-side surface S6 of the third lens element L3 is concave along the optical axis, and the image-side surface S7 of the third lens element L3 is convex along the optical axis; the object-side surface S6 of the third lens element L3 is concave at the circumference, and the image-side surface S7 of the third lens element L3 is convex at the circumference. The object-side surface S8 of the fourth lens element L4 is convex along the optical axis, and the image-side surface S9 of the fourth lens element L4 is concave along the optical axis; the object-side surface S8 of the fourth lens element L4 is concave at the circumference, and the image-side surface S9 of the fourth lens element L4 is concave at the circumference. The object-side surface S10 of the fifth lens element L5 is concave along the optical axis, and the image-side surface S11 of the fifth lens element L5 is convex along the optical axis; the object-side surface S10 of the fifth lens element L5 is concave at the circumference, and the image-side surface S11 of the fifth lens element L5 is convex at the circumference. The object-side surface S12 of the sixth lens element L6 is convex along the optical axis, and the image-side surface S13 of the sixth lens element L6 is concave along the optical axis; the object-side surface S12 of the sixth lens element L6 is concave at the circumference, and the image-side surface S13 of the sixth lens element L6 is convex at the circumference. The object-side surface S14 of the seventh lens element L7 is concave along the optical axis, and the image-side surface S15 of the seventh lens element L7 is concave along the optical axis; the object-side surface S14 of the seventh lens element L7 is concave at the circumference, and the image-side surface S15 of the seventh lens element L7 is convex at the circumference.

In the second embodiment, the total effective focal length f of the optical assembly 10 is 4.21mm, the aperture value FNO is 1.45, the maximum field angle FOV is 76.74 degrees (deg.), and the distance TTL from the object-side surface S2 of the first lens L1 to the image plane S18 on the optical axis is 5.40 mm.

In addition, the parameters of the optical assembly 10 are given in tables 3 and 4, and the definitions of the parameters are the same as those in the first embodiment, which are not repeated herein.

TABLE 3

TABLE 4

The following data can be derived according to the provided parameter information:

third embodiment

In the third embodiment shown in fig. 5, the optical assembly 10 includes, in order from an object side to an image side, a stop ST0, a first lens element L1 with positive refractive power, a second lens element L2 with positive refractive power, a third lens element L3 with negative refractive power, a fourth lens element L4 with negative refractive power, a fifth lens element L5 with positive refractive power, a sixth lens element L6 with positive refractive power, a seventh lens element L7 with negative refractive power, and an infrared filter 110. Fig. 6 is a spherical aberration diagram (mm), an astigmatism diagram (mm) and a distortion diagram (%) of the optical assembly 10 in the third embodiment, wherein the astigmatism diagram and the distortion diagram are data diagrams at a reference wavelength.

The object-side surface S2 of the first lens element L1 is convex along the optical axis, and the image-side surface S3 of the first lens element L1 is concave along the optical axis; the object-side surface S2 of the first lens element L1 is convex at the circumference, and the image-side surface S3 of the first lens element L1 is concave at the circumference. The object-side surface S4 of the second lens element L2 is convex along the optical axis, and the image-side surface S5 of the second lens element L2 is concave along the optical axis; the object-side surface S4 of the second lens element L2 is convex at the circumference, and the image-side surface S5 of the second lens element L2 is convex at the circumference. The object-side surface S6 of the third lens element L3 is concave along the optical axis, and the image-side surface S7 of the third lens element L3 is convex along the optical axis; the object-side surface S6 of the third lens element L3 is concave at the circumference, and the image-side surface S7 of the third lens element L3 is convex at the circumference. The object-side surface S8 of the fourth lens element L4 is concave along the optical axis, and the image-side surface S9 of the fourth lens element L4 is concave along the optical axis; the object-side surface S8 of the fourth lens element L4 is concave at the circumference, and the image-side surface S9 of the fourth lens element L4 is concave at the circumference. The object-side surface S10 of the fifth lens element L5 is concave along the optical axis, and the image-side surface S11 of the fifth lens element L5 is convex along the optical axis; the object-side surface S10 of the fifth lens element L5 is concave at the circumference, and the image-side surface S11 of the fifth lens element L5 is convex at the circumference. The object-side surface S12 of the sixth lens element L6 is convex along the optical axis, and the image-side surface S13 of the sixth lens element L6 is convex along the optical axis; the object-side surface S12 of the sixth lens element L6 is concave at the circumference, and the image-side surface S13 of the sixth lens element L6 is convex at the circumference. The object-side surface S14 of the seventh lens element L7 is concave along the optical axis, and the image-side surface S15 of the seventh lens element L7 is concave along the optical axis; the object-side surface S14 of the seventh lens element L7 is concave at the circumference, and the image-side surface S15 of the seventh lens element L7 is convex at the circumference.

In the third embodiment, the total effective focal length f of the optical assembly 10 is 4.24mm, the aperture value FNO is 1.4, the maximum field angle FOV is 76.6 degrees (deg.), and the distance TTL from the object-side surface S2 of the first lens L1 to the image plane S18 on the optical axis is 5.49 mm.

In addition, the parameters of the optical assembly 10 are given in tables 5 and 6, and the definitions of the parameters are the same as those in the first embodiment, which are not repeated herein.

TABLE 5

TABLE 6

fourth embodiment

In the fourth embodiment as shown in fig. 7, the optical assembly 10 includes, in order from an object side to an image side, a stop ST0, a first lens element L1 with positive refractive power, a second lens element L2 with positive refractive power, a third lens element L3 with negative refractive power, a fourth lens element L4 with negative refractive power, a fifth lens element L5 with positive refractive power, a sixth lens element L6 with positive refractive power, a seventh lens element L7 with negative refractive power, and an infrared filter 110. Fig. 8 is a spherical aberration diagram (mm), an astigmatism diagram (mm) and a distortion diagram (%) of the optical assembly 10 in the fourth embodiment, wherein the astigmatism diagram and the distortion diagram are data diagrams at a reference wavelength.

The object-side surface S2 of the first lens element L1 is convex along the optical axis, and the image-side surface S3 of the first lens element L1 is concave along the optical axis; the object-side surface S2 of the first lens element L1 is convex at the circumference, and the image-side surface S3 of the first lens element L1 is concave at the circumference. The object-side surface S4 of the second lens element L2 is convex along the optical axis, and the image-side surface S5 of the second lens element L2 is convex along the optical axis; the object-side surface S4 of the second lens element L2 is convex at the circumference, and the image-side surface S5 of the second lens element L2 is convex at the circumference. The object-side surface S6 of the third lens element L3 is concave along the optical axis, and the image-side surface S7 of the third lens element L3 is convex along the optical axis; the object-side surface S6 of the third lens element L3 is concave at the circumference, and the image-side surface S7 of the third lens element L3 is convex at the circumference. The object-side surface S8 of the fourth lens element L4 is convex along the optical axis, and the image-side surface S9 of the fourth lens element L4 is concave along the optical axis; the object-side surface S8 of the fourth lens element L4 is concave at the circumference, and the image-side surface S9 of the fourth lens element L4 is concave at the circumference. The object-side surface S10 of the fifth lens element L5 is concave along the optical axis, and the image-side surface S11 of the fifth lens element L5 is convex along the optical axis; the object-side surface S10 of the fifth lens element L5 is concave at the circumference, and the image-side surface S11 of the fifth lens element L5 is convex at the circumference. The object-side surface S12 of the sixth lens element L6 is convex along the optical axis, and the image-side surface S13 of the sixth lens element L6 is concave along the optical axis; the object-side surface S12 of the sixth lens element L6 is concave at the circumference, and the image-side surface S13 of the sixth lens element L6 is convex at the circumference. The object-side surface S14 of the seventh lens element L7 is convex along the optical axis, and the image-side surface S15 of the seventh lens element L7 is concave along the optical axis; the object-side surface S14 of the seventh lens element L7 is concave at the circumference, and the image-side surface S15 of the seventh lens element L7 is convex at the circumference.

The object-side surface and the image-side surface of the first lens L1, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6 and the seventh lens L7 are aspheric. The object-side surface S4 of the second lens L2 is spherical, and the image-side surface S5 of the second lens L2 is aspherical.

In the fourth embodiment, the total effective focal length f of the optical assembly 10 is 3.93mm, the aperture value FNO is 1.55, the maximum field angle FOV is 82.8 degrees (deg.), and the distance TTL from the object-side surface S2 of the first lens L1 to the image plane S18 on the optical axis is 5.06 mm.

In addition, the parameters of the optical assembly 10 are given in tables 7 and 8, and the definitions of the parameters are the same as those in the first embodiment, which are not repeated herein.

TABLE 7

TABLE 8

fifth embodiment

In the fifth embodiment shown in fig. 9, the optical assembly 10 includes, in order from an object side to an image side, a stop ST0, a first lens element L1 with positive refractive power, a second lens element L2 with positive refractive power, a third lens element L3 with negative refractive power, a fourth lens element L4 with negative refractive power, a fifth lens element L5 with positive refractive power, a sixth lens element L6 with positive refractive power, a seventh lens element L7 with negative refractive power, and an infrared filter 110. Fig. 10 is a spherical aberration diagram (mm), an astigmatism diagram (mm) and a distortion diagram (%) of the optical assembly 10 in the fifth embodiment, wherein the astigmatism diagram and the distortion diagram are data diagrams at a reference wavelength.

The object-side surface S2 of the first lens element L1 is convex along the optical axis, and the image-side surface S3 of the first lens element L1 is concave along the optical axis; the object-side surface S2 of the first lens element L1 is convex at the circumference, and the image-side surface S3 of the first lens element L1 is concave at the circumference. The object-side surface S4 of the second lens element L2 is convex along the optical axis, and the image-side surface S5 of the second lens element L2 is convex along the optical axis; the object-side surface S4 of the second lens element L2 is convex at the circumference, and the image-side surface S5 of the second lens element L2 is convex at the circumference. The object-side surface S6 of the third lens element L3 is concave along the optical axis, and the image-side surface S7 of the third lens element L3 is convex along the optical axis; the object-side surface S6 of the third lens element L3 is concave at the circumference, and the image-side surface S7 of the third lens element L3 is concave at the circumference. The object-side surface S8 of the fourth lens element L4 is convex along the optical axis, and the image-side surface S9 of the fourth lens element L4 is concave along the optical axis; the object-side surface S8 of the fourth lens element L4 is concave at the circumference, and the image-side surface S9 of the fourth lens element L4 is convex at the circumference. The object-side surface S10 of the fifth lens element L5 is concave along the optical axis, and the image-side surface S11 of the fifth lens element L5 is convex along the optical axis; the object-side surface S10 of the fifth lens element L5 is concave at the circumference, and the image-side surface S11 of the fifth lens element L5 is convex at the circumference. The object-side surface S12 of the sixth lens element L6 is convex along the optical axis, and the image-side surface S13 of the sixth lens element L6 is concave along the optical axis; the object-side surface S12 of the sixth lens element L6 is concave at the circumference, and the image-side surface S13 of the sixth lens element L6 is convex at the circumference. The object-side surface S14 of the seventh lens element L7 is convex along the optical axis, and the image-side surface S15 of the seventh lens element L7 is concave along the optical axis; the object-side surface S14 of the seventh lens element L7 is convex at the circumference, and the image-side surface S15 of the seventh lens element L7 is convex at the circumference.

In the fifth embodiment, the total effective focal length f of the optical assembly 10 is 3.97mm, the aperture value FNO is 1.55, the maximum field angle FOV is 80.5 degrees (deg.), and the distance TTL from the object-side surface S2 of the first lens L1 to the image plane S18 on the optical axis is 5.18 mm.

In addition, the parameters of the optical assembly 10 are given in tables 9 and 10, and the definitions of the parameters are the same as those in the first embodiment, which are not repeated herein.

TABLE 9

Watch 10

sixth embodiment

In the sixth embodiment shown in fig. 11, the optical assembly 10 includes, in order from an object side to an image side, a stop ST0, a first lens element L1 with positive refractive power, a second lens element L2 with positive refractive power, a third lens element L3 with negative refractive power, a fourth lens element L4 with negative refractive power, a fifth lens element L5 with positive refractive power, a sixth lens element L6 with positive refractive power, a seventh lens element L7 with negative refractive power, and an infrared filter 110. Fig. 12 is a spherical aberration diagram (mm), an astigmatism diagram (mm) and a distortion diagram (%) of the optical assembly 10 in the sixth embodiment, wherein the astigmatism diagram and the distortion diagram are data diagrams at a reference wavelength.

The object-side surface S2 of the first lens element L1 is convex along the optical axis, and the image-side surface S3 of the first lens element L1 is concave along the optical axis; the object-side surface S2 of the first lens element L1 is convex at the circumference, and the image-side surface S3 of the first lens element L1 is concave at the circumference. The object-side surface S4 of the second lens element L2 is convex along the optical axis, and the image-side surface S5 of the second lens element L2 is convex along the optical axis; the object-side surface S4 of the second lens element L2 is convex at the circumference, and the image-side surface S5 of the second lens element L2 is convex at the circumference. The object-side surface S6 of the third lens element L3 is concave along the optical axis, and the image-side surface S7 of the third lens element L3 is convex along the optical axis; the object-side surface S6 of the third lens element L3 is concave at the circumference, and the image-side surface S7 of the third lens element L3 is convex at the circumference. The object-side surface S8 of the fourth lens element L4 is convex along the optical axis, and the image-side surface S9 of the fourth lens element L4 is concave along the optical axis; the object-side surface S8 of the fourth lens element L4 is concave at the circumference, and the image-side surface S9 of the fourth lens element L4 is convex at the circumference. The object-side surface S10 of the fifth lens element L5 is concave along the optical axis, and the image-side surface S11 of the fifth lens element L5 is convex along the optical axis; the object-side surface S10 of the fifth lens element L5 is concave at the circumference, and the image-side surface S11 of the fifth lens element L5 is convex at the circumference. The object-side surface S12 of the sixth lens element L6 is convex along the optical axis, and the image-side surface S13 of the sixth lens element L6 is concave along the optical axis; the object-side surface S12 of the sixth lens element L6 is concave at the circumference, and the image-side surface S13 of the sixth lens element L6 is convex at the circumference. The object-side surface S14 of the seventh lens element L7 is convex along the optical axis, and the image-side surface S15 of the seventh lens element L7 is concave along the optical axis; the object-side surface S14 of the seventh lens element L7 is convex at the circumference, and the image-side surface S15 of the seventh lens element L7 is convex at the circumference.

In the sixth embodiment, the total effective focal length f of the optical assembly 10 is 4.02mm, the aperture value FNO is 1.7, the maximum field angle FOV is 81.4 degrees (deg.), and the distance TTL from the object-side surface S2 of the first lens L1 to the image plane S18 on the optical axis is 5.21 mm.

In addition, the parameters of the optical assembly 10 are given in tables 11 and 12, and the definitions of the parameters are the same as those in the first embodiment, which are not repeated herein.

TABLE 11

TABLE 12

seventh embodiment

In the seventh embodiment shown in fig. 13, the optical assembly 10 includes, in order from an object side to an image side, the first lens element L1 with positive refractive power, the stop ST0, the second lens element L2 with positive refractive power, the third lens element L3 with negative refractive power, the fourth lens element L4 with positive refractive power, the fifth lens element L5 with negative refractive power, the sixth lens element L6 with positive refractive power, the seventh lens element L7 with negative refractive power, and the infrared filter 110. Fig. 14 is a spherical aberration diagram (mm), an astigmatism diagram (mm) and a distortion diagram (%) of the optical assembly 10 in the seventh embodiment, wherein the astigmatism diagram and the distortion diagram are data diagrams at a reference wavelength.

The object-side surface S2 of the first lens element L1 is convex along the optical axis, and the image-side surface S3 of the first lens element L1 is concave along the optical axis; the object-side surface S2 of the first lens element L1 is convex at the circumference, and the image-side surface S3 of the first lens element L1 is concave at the circumference. The object-side surface S4 of the second lens element L2 is convex along the optical axis, and the image-side surface S5 of the second lens element L2 is concave along the optical axis; the object-side surface S4 of the second lens element L2 is convex at the circumference, and the image-side surface S5 of the second lens element L2 is convex at the circumference. The object-side surface S6 of the third lens element L3 is concave along the optical axis, and the image-side surface S7 of the third lens element L3 is convex along the optical axis; the object-side surface S6 of the third lens element L3 is concave at the circumference, and the image-side surface S7 of the third lens element L3 is convex at the circumference. The object-side surface S8 of the fourth lens element L4 is convex along the optical axis, and the image-side surface S9 of the fourth lens element L4 is concave along the optical axis; the object-side surface S8 of the fourth lens element L4 is concave at the circumference, and the image-side surface S9 of the fourth lens element L4 is convex at the circumference. The object-side surface S10 of the fifth lens element L5 is concave along the optical axis, and the image-side surface S11 of the fifth lens element L5 is convex along the optical axis; the object-side surface S10 of the fifth lens element L5 is concave at the circumference, and the image-side surface S11 of the fifth lens element L5 is convex at the circumference. The object-side surface S12 of the sixth lens element L6 is convex along the optical axis, and the image-side surface S13 of the sixth lens element L6 is convex along the optical axis; the object-side surface S12 of the sixth lens element L6 is concave at the circumference, and the image-side surface S13 of the sixth lens element L6 is convex at the circumference. The object-side surface S14 of the seventh lens element L7 is concave along the optical axis, and the image-side surface S15 of the seventh lens element L7 is concave along the optical axis; the object-side surface S14 of the seventh lens element L7 is concave at the circumference, and the image-side surface S15 of the seventh lens element L7 is convex at the circumference.

The object-side surface and the image-side surface of the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6 and the seventh lens L7 are aspheric. In addition, both the object-side surface and the image-side surface of the first lens element L1 are spherical.

In the seventh embodiment, the total effective focal length f of the optical assembly 10 is 4.17mm, the aperture value FNO is 1.98, the maximum field angle FOV is 79.5 degrees (deg.), and the distance TTL from the object-side surface S2 of the first lens L1 to the image plane S18 on the optical axis is 5.50 mm.

In addition, the parameters of the optical assembly 10 are given in tables 13 and 14, and the definitions of the parameters are the same as those in the first embodiment, which are not repeated herein. However, it should be noted that, in the present embodiment, the surface numbers of the elements change due to the variation of the position of the diaphragm, so the definition of the corresponding parameters shall be based on the elements in the table, and the surface numbers shall not be used to explain the parameters.

Watch 13

TABLE 14

as shown in fig. 15, in some embodiments, the image capturing module 20 includes an optical assembly 10 and a photo sensor 210 disposed on an image side of the optical assembly 10. Specifically, in some embodiments, the photosensitive chip 210 is disposed on the imaging surface S18 of the optical assembly 10. In some embodiments, the photosensitive chip 210 may be a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor). After the optical assembly 10 is adopted, the camera module 20 has a larger light-transmitting aperture to obtain a larger light-transmitting amount, and still has better imaging quality under the condition of insufficient ambient light.

For example, the light ray carrying the image information of the object enters the optical assembly 10 from the object side of the optical assembly 10, passes through the stop ST0, the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, and the infrared filter 110 in sequence, reaches the photosensitive element 210, and is received by the photosensitive element 210. Subsequently, the image information is converted from the optical signal into an electrical signal, and the electrical signal is transmitted to the image processor through a circuit board electrically connected to the photo chip 210.

In some embodiments, the camera module 20 further includes a fixing member for fixing the optical assembly 10 and the photosensitive chip 210. The optical assembly 10 and the photosensitive chip 210 are disposed opposite to each other in the fixing member by dispensing. In some embodiments, the fixing member has an integral structure, and the optical assembly 10 and the photosensitive element 210 are relatively fixedly disposed, in which case the camera module 20 is a fixed-focus camera module.

In some embodiments, the fixing member includes a first fixing member and a second fixing member, which are independent from each other, the first fixing member fixes the optical assembly 10, and the second fixing member fixes the photosensitive chip 210. In some embodiments, the first fixing member and the second fixing member are relatively fixed, that is, the optical assembly 10 and the photosensitive chip 210 are relatively fixed, and the camera module 20 can be used as a fixed-focus camera module. In other embodiments, the camera module 20 is further provided with a voice coil motor, and the voice coil motor is respectively connected to the first fixing member and the second fixing member, so that the first fixing member can move relative to the second fixing member, and thus the optical assembly 10 can move relative to the photosensitive chip 210 under the action of the voice coil motor, so that the camera module 20 has a focusing function.

As shown in fig. 16, the camera module 20 is applicable to the mobile terminal 30. The mobile terminal 30 may be an electronic device such as a miniaturized smart phone, a camera phone, a digital camera, a game machine, a tablet computer, and a PC, or may be a camera lens in a home appliance having a camera function. In some embodiments, the camera module 20 may be a front camera or a rear camera of the mobile terminal 30.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. An optical assembly, comprising, in order from an object side to an image side:

a fourth lens element with refractive power;

a fifth lens element with refractive power;

the optical assembly satisfies the following relationship:

f/EPD＜2.00；

2. The optical assembly of claim 1, wherein the optical assembly satisfies the following relationship:

-1.00＜f12/f34＜0；

wherein f12 is a composite focal length of the first lens and the second lens, and f34 is a composite focal length of the third lens and the fourth lens.

3. The optical assembly of claim 1, wherein the optical assembly satisfies the following relationship:

0.35＜Y32/Y72＜0.50；

wherein Y32 is a maximum effective radius of an image-side surface of the third lens, and Y72 is a maximum effective radius of an image-side surface of the seventh lens.

4. The optical assembly of claim 1, wherein the optical assembly satisfies the following relationship:

-1.50＜f/f7＜0；

wherein f7 is the focal length of the seventh lens.

5. The optical assembly of claim 1, wherein the optical assembly satisfies the following relationship:

0＜f1/f＜3.10；

wherein f1 is the focal length of the first lens.

6. The optical assembly of claim 1, wherein the optical assembly satisfies the following relationship:

0.50＜R12/R21＜1.00；

wherein R12 is a curvature radius of the image side surface of the first lens at the optical axis, and R21 is a curvature radius of the object side surface of the second lens at the optical axis.

7. The optical assembly of claim 1, wherein the optical assembly satisfies the following relationship:

TTL/ImgH＜1.60；

wherein, TTL is a distance on an optical axis from an object-side surface of the first lens element to an imaging surface of the optical element, and ImgH is a half of a diagonal length of an effective pixel area of the optical element on the imaging surface.

8. The optical assembly of claim 1, wherein the optical assembly satisfies the following relationship:

3.00＜(CT1+CT2)/CT3＜5.00；

wherein CT1 is the thickness of the first lens element on the optical axis, CT2 is the thickness of the second lens element on the optical axis, and CT3 is the thickness of the third lens element on the optical axis.

9. The optical assembly of claim 1, wherein the optical assembly satisfies the following relationship:

0.20＜(T45+T56)/T67＜1.20；

wherein T45 is an axial distance between the fourth lens element and the fifth lens element, T56 is an axial distance between the fifth lens element and the sixth lens element, and T67 is an axial distance between the sixth lens element and the seventh lens element.

10. The optical assembly of claim 1, further comprising an optical stop disposed on an object side of the first lens or between the first lens and the second lens.

11. A camera module comprising a photosensitive element and the optical assembly of any one of claims 1-10, wherein the photosensitive element is disposed on an image side of the optical assembly.

12. A mobile terminal characterized by comprising the camera module of claim 11.