CN116643388B

CN116643388B - optical lens

Info

Publication number: CN116643388B
Application number: CN202310906174.3A
Authority: CN
Inventors: 龚佳豪; 王钰文; 谢雨辰; 章彬炜
Original assignee: Jiangxi Lianyi Optics Co Ltd
Current assignee: Jiangxi Lianyi Optics Co Ltd
Priority date: 2023-07-24
Filing date: 2023-07-24
Publication date: 2023-11-14
Anticipated expiration: 2043-07-24
Also published as: CN116643388A

Abstract

The application discloses an optical lens, which sequentially comprises from an object side to an imaging surface along an optical axis: a first lens element with negative refractive power having a concave object-side surface at a paraxial region and a concave image-side surface; a second lens element with positive refractive power having a convex object-side surface and a concave image-side surface; a third lens having positive optical power, both the object-side surface and the image-side surface of which are convex; a fourth lens having negative optical power; a fifth lens element with negative refractive power having a concave object-side surface and a convex image-side surface; a sixth lens element with positive refractive power having a concave object-side surface and a convex image-side surface at a paraxial region; a seventh lens element with negative refractive power having an object-side surface being convex at a paraxial region and an image-side surface being concave at a paraxial region; the optical lens satisfies the following conditional expression: 1.8< TTL/f <2.3, wherein TTL represents the total optical length of the optical lens, and f represents the effective focal length of the optical lens. The optical lens provided by the application has the advantages of large wide angle, large image plane and high pixel.

Description

Optical lens

Technical Field

The application relates to the technical field of imaging lenses, in particular to an optical lens.

Background

Currently, with the popularization of portable electronic devices (such as smartphones, tablets and cameras), and the popularity of social, video and live broadcast software, people have a higher and higher preference for photography, and a camera lens has become a standard of the electronic devices, and even has become an index of primary consideration when consumers purchase the electronic devices.

With the continuous upgrading and updating of smart phones, the requirements of consumers on the shooting functions of the mobile phones are higher and higher, the ultra-high pixel, the wide angle and the light and thin imaging lens become main development trend of the mobile phone lens, so that the imaging lens carried on the portable electronic equipment is required to be higher, the pixel point size of the sensor chip is kept not to be reduced while the pixel point is high, and the increase of the size of the sensor chip becomes an important development trend of the high pixel. In addition, the camera with the wide angle gradually becomes the standard of flagship machines of all main stream mobile phone manufacturers so as to meet the shooting requirement of the ultra-wide angle. The distortion of the large wide-angle lens which is common in the market at present is large, the deformation and stretching of the image are obvious, the proportion is not coordinated, and the distortion needs to be corrected by means of a later software algorithm, so that the problem to be solved is urgent how to better realize the balance of the large wide angle, the small distortion, the high pixels and the small volume of the optical lens.

Disclosure of Invention

In view of the above problems, an object of the present application is to provide an optical lens capable of satisfying the demands for ultra-thinning and wide-angle while achieving high pixel imaging performance.

The embodiment of the application realizes the aim through the following technical scheme.

The application provides an optical lens, which sequentially comprises from an object side to an imaging surface along an optical axis: a first lens element with negative refractive power having a concave object-side surface at a paraxial region and a concave image-side surface; a second lens element with positive refractive power having a convex object-side surface and a concave image-side surface; a third lens having positive optical power, both the object-side surface and the image-side surface of which are convex; a fourth lens having negative optical power; a fifth lens element with negative refractive power having a concave object-side surface and a convex image-side surface; a sixth lens element with positive refractive power having a concave object-side surface and a convex image-side surface at a paraxial region; a seventh lens element with negative refractive power having an object-side surface being convex at a paraxial region and an image-side surface being concave at a paraxial region; wherein, the optical lens satisfies the conditional expression: 1.8< TTL/f <2.3, TTL represents the total optical length of the optical lens, and f represents the effective focal length of the optical lens.

Compared with the prior art, the optical lens provided by the application adopts seven lenses with specific focal power, and has the characteristics of a relatively compact structure and relatively high pixels through specific surface shape collocation and reasonable focal power distribution, and can be compatible with 50MP (Megapixel) and 108MP large target surface sensor chips to realize ultra-high definition imaging; meanwhile, as the surface type and focal power of each lens are reasonably matched, the lens has larger angle of view and smaller distortion, the resolution of the lens and the degree of restoration of image details can be improved, and the resolving power of the lens can be improved.

Drawings

The foregoing and/or additional aspects and advantages of the application will become apparent and may be better understood from the following description of embodiments taken in conjunction with the accompanying drawings in which:

fig. 1 is a schematic structural diagram of an optical lens according to a first embodiment of the present application.

Fig. 2 is a distortion graph of an optical lens according to a first embodiment of the present application.

Fig. 3 is a graph showing a field curvature of an optical lens according to a first embodiment of the present application.

Fig. 4 is a vertical axis chromatic aberration diagram of an optical lens according to a first embodiment of the present application.

Fig. 5 is an axial chromatic aberration diagram of an optical lens according to a first embodiment of the present application.

Fig. 6 is a schematic structural diagram of an optical lens according to a second embodiment of the present application.

Fig. 7 is a distortion graph of an optical lens according to a second embodiment of the present application.

Fig. 8 is a field curvature chart of an optical lens according to a second embodiment of the present application.

Fig. 9 is a vertical axis chromatic aberration diagram of an optical lens according to a second embodiment of the present application.

Fig. 10 is an axial chromatic aberration diagram of an optical lens according to a second embodiment of the present application.

Fig. 11 is a schematic structural diagram of an optical lens according to a third embodiment of the present application.

Fig. 12 is a distortion graph of an optical lens according to a third embodiment of the present application.

Fig. 13 is a field curve diagram of an optical lens according to a third embodiment of the present application.

Fig. 14 is a vertical axis chromatic aberration diagram of an optical lens according to a third embodiment of the present application.

Fig. 15 is an axial chromatic aberration diagram of an optical lens according to a third embodiment of the present application.

Fig. 16 is a schematic structural view of an optical lens according to a fourth embodiment of the present application.

Fig. 17 is a distortion graph of an optical lens according to a fourth embodiment of the present application.

Fig. 18 is a field curvature graph of an optical lens according to a fourth embodiment of the present application.

Fig. 19 is a vertical axis chromatic aberration diagram of an optical lens according to a fourth embodiment of the present application.

Fig. 20 is an axial chromatic aberration diagram of an optical lens according to a fourth embodiment of the present application.

Fig. 21 is a distortion graph of an optical lens according to a fifth embodiment of the present application.

Fig. 22 is a field curvature chart of an optical lens according to a fifth embodiment of the present application.

Fig. 23 is a vertical axis chromatic aberration diagram of an optical lens according to a fifth embodiment of the present application.

Fig. 24 is an axial chromatic aberration chart of an optical lens according to a fifth embodiment of the application.

Fig. 25 is a distortion graph of an optical lens according to a sixth embodiment of the present application.

Fig. 26 is a field curvature graph of an optical lens according to a sixth embodiment of the present application.

Fig. 27 is a vertical axis chromatic aberration diagram of an optical lens according to a sixth embodiment of the present application.

Fig. 28 is an axial chromatic aberration chart of an optical lens according to a sixth embodiment of the application.

Detailed Description

In order that the objects, features and advantages of the application will be readily understood, a more particular description of the application will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. Several embodiments of the application are presented in the figures. This application 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.

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 application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. Like reference numerals refer to like elements throughout the specification.

In this context, near the optical axis means the area near the optical axis. If the lens surface is convex and the convex position is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the concave position is not defined, it means that the lens surface is concave at least in the paraxial region.

The application provides an optical lens, which sequentially comprises from an object side to an imaging surface along an optical axis: the optical lens comprises a first lens, a second lens, a diaphragm, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens and an optical filter.

The first lens has negative focal power, the object side surface of the first lens is concave at a paraxial region, and the image side surface of the first lens is concave.

The second lens has positive focal power, the object side surface is a convex surface, and the image side surface is a concave surface.

The third lens has positive focal power, and both the object side surface and the image side surface of the third lens are convex.

The fourth lens has negative optical power.

The fifth lens has negative focal power, the object side surface is concave, and the image side surface is convex.

The sixth lens element has positive refractive power, wherein an object-side surface thereof is concave, and an image-side surface thereof is convex at a paraxial region.

The seventh lens element has negative refractive power, wherein an object-side surface thereof is convex at a paraxial region and an image-side surface thereof is concave at the paraxial region.

The optical lens further comprises a diaphragm, wherein the diaphragm is used for limiting the light entering quantity so as to change the brightness of imaging. When the diaphragm is located between the second lens and the third lens, the diaphragm can reasonably distribute the functions of the first lens to the seventh lens, for example, the first lens and the second lens can be used for receiving light rays with large field angles to a large extent, and large wide-angle imaging of the lens is better achieved. The third lens to the seventh lens can be used to correct aberrations, achieving higher performance imaging quality. The optical lens provided in the embodiment has the advantages that the diaphragm is arranged in the optical lens, the number of lenses for enlarging the angle of view is small, and the structure of the optical lens is simplified; the number of lenses for correcting aberrations is large, which is advantageous for obtaining a better imaging quality. Further, when the diaphragm is located between the second lens and the third lens, correction of diaphragm aberration is facilitated.

In some embodiments, the optical lens satisfies the following conditional expression: 1.8< TTL/f <2.3, TTL represents the total optical length of the optical lens, and f represents the effective focal length of the optical lens. The system can have a more compact structure and can better realize the miniaturization of the system by meeting the conditions.

In some embodiments, the optical lens satisfies the following conditional expression: -3< f1/f < -1, -6< R11/R12< -2, wherein f1 represents a focal length of the first lens, R11 represents a radius of curvature of an object side of the first lens, and R12 represents a radius of curvature of an image side of the first lens. The first lens has proper negative focal power and surface shape, can slow down the deflection degree of incident light, is beneficial to the light in a larger range to enter the optical system, is beneficial to enlarging the field angle of the lens, is beneficial to reducing the aberration of the system, and realizes the development of the lens to ultra-thin and wide angle.

In some embodiments, the optical lens satisfies the following conditional expression: 2< f2/f <3,0.7< R21/R22<1.15, wherein f2 represents a focal length of the second lens, R21 represents a radius of curvature of an object side of the second lens, and R22 represents a radius of curvature of an image side of the second lens. The lens has the advantages that the positive focal power and the surface shape of the second lens are reasonably set, the deflection degree of incident light rays can be slowed down, the view field angle of the system is improved, the distortion correction difficulty of the marginal view field is reduced while the view field angle is increased, the lens has smaller distortion, and meanwhile, the spherical aberration generated by the first lens can be effectively balanced, and the overall imaging quality is improved.

In some embodiments, the optical lens satisfies the following conditional expression: 0.9< f3/f <1.5, -3.5< R31/R32< -1 >, wherein f3 represents a focal length of the third lens, R31 represents a radius of curvature of an object side of the third lens, and R32 represents a radius of curvature of an image side of the third lens. The third lens can bear reasonable positive focal power, the deflection degree of light passing through the lens can be alleviated, the field curvature and distortion of the system are effectively reduced, and the imaging quality is improved.

In some embodiments, the optical lens satisfies the following conditional expression: -1.2< f1/f2< -0.7,1.8< R12/R22<5, wherein f1 represents the focal length of the first lens, f2 represents the focal length of the second lens, R12 represents the radius of curvature of the image side of the first lens, and R22 represents the radius of curvature of the image side of the second lens. The optical system has the advantages that the focal length ratio of the first lens and the second lens is reasonably set, so that the light deflection degree entering the lens can be effectively prevented from being too large, the sensitivity of the optical system is reduced, the distortion correction difficulty of the system is reduced, and the overall imaging quality is improved.

In some embodiments, the optical lens satisfies the following conditional expression: 0.85< f3/f6<1.6,3< f4/f7<8, wherein f3 represents a focal length of the third lens, f4 represents a focal length of the fourth lens, f6 represents a focal length of the sixth lens, and f7 represents a focal length of the seventh lens. The lens has the advantages that the focal length of each lens is reasonably distributed, so that the overlarge deflection degree of light rays passing through the system can be avoided, the aberration correction difficulty is reduced, meanwhile, the field curvature and distortion of the lens can be better corrected, the field curvature and distortion of the lens are ensured to be controlled at smaller levels, and the high-pixel imaging of the system is realized.

In some embodiments, the optical lens satisfies the following conditional expression: -100< R61/f < -1, R61/R62>2, wherein R61 represents a radius of curvature of an object-side surface of the sixth lens, and R62 represents a radius of curvature of an image-side surface of the sixth lens. The method has the advantages that the shape change of the sixth lens can be slowed down by reasonably adjusting the surface shape of the sixth lens, stray light is reduced, meanwhile, the light trend can be reasonably controlled, the incident angle of light entering an image surface is increased, the large image surface is realized, and meanwhile, the problem of overhigh lens sensitivity caused by overlarge light deflection degree is avoided.

In some embodiments, the optical lens satisfies the following conditional expression: 0.9< CT1/CT2<1.35, wherein CT1 represents a center thickness of the first lens and CT2 represents a center thickness of the second lens. The lens has the advantages that the central thicknesses of the first lens and the second lens are reasonably set, the light distribution is favorably adjusted, the light passes through the lens to be excessively gentle, the control of lens distortion is favorably realized, the lens has a wide viewing angle and smaller distortion, the resolution ratio and the image detail reduction degree of the lens can be improved, and the resolution of the lens is improved.

In some embodiments, the optical lens satisfies the following conditional expression: 0.38< ET6/CT6<0.45, wherein ET6 represents an edge thickness of the sixth lens and CT6 represents a center thickness of the sixth lens. The ratio of the edge thickness to the center thickness of the lens of the sixth lens is controlled to enable the sixth lens to have proper thickness ratio, so that the forming uniformity of the sixth lens is improved, production defects of the same lens due to overlarge thickness difference are reduced, and the overall imaging quality is improved.

In some embodiments, the optical lens satisfies the following conditional expression: 0.5< DM6/DM7<0.62, -2.5< R62/R72< -0.5, wherein DM6 represents the maximum effective aperture of the sixth lens, DM7 represents the maximum effective aperture of the seventh lens, R62 represents the radius of curvature of the image side of the sixth lens, and R72 represents the radius of curvature of the image side of the seventh lens. The aperture and the surface shape of the sixth lens and the seventh lens are reasonably arranged, so that the deflection degree of light is reasonably controlled, the incident angle of the light entering an image surface can be increased, the imaging of a large target surface of the lens is realized, and the high-pixel imaging of the lens can be better matched with a large-size chip.

In some embodiments, the optical lens satisfies the following conditional expression: 2.8< IH/f <3.2,5.0mm < IH/FNo <5.5mm, wherein IH represents the image height corresponding to the maximum field angle of the optical lens, and FNo represents the aperture value of the optical lens. The method and the device meet the conditions, are favorable for realizing the large aperture characteristic of the lens while realizing the large field angle of the lens, are favorable for the optical lens to acquire more scene information, meet the requirement of large-scale shooting, and are favorable for improving the problem of rapid relative brightness decline of the edge field of view caused by the wide angle, thereby being favorable for acquiring more scene information.

In some embodiments, the optical lens satisfies the following conditional expression: 0.09mm/° < IH/FOV <0.1mm/°, wherein FOV represents the maximum field angle of the optical lens and IH represents the image height corresponding to the maximum field angle of the optical lens. The wide-angle characteristic of the lens can be achieved, so that the requirement of large-range shooting is met, the characteristic of a large image plane can be achieved, the imaging quality of the optical lens is improved, and the requirements of large-range detection and high-quality imaging can be effectively balanced.

In some embodiments, the optical lens satisfies the following conditional expression: 0.35 < BFL/f <0.45, wherein BFL represents the optical back focus of the optical lens. The length of the focal length of the lens determines the imaging size of the shot object on the sensor chip, namely the scale corresponding to the object and the image. When shooting the same shot object at the same distance, the imaging with long lens focal length is large, and the imaging with short lens focal length is small. The range is satisfied, the imaging is relatively large due to the matched optical back focus and focal length, so that the pixels of the optical lens are high, and the high-pixel imaging of the lens is realized.

As an implementation mode, a full plastic lens can be adopted, and good imaging effect can be obtained by adopting glass-plastic mixing and matching; in the application, in order to better reduce the volume of the lens and reduce the cost, seven plastic lens combinations are adopted, and the lens has the advantages of at least good imaging quality, large wide angle, large image surface, low sensitivity and miniaturization by reasonably distributing the focal power of each lens and optimizing the aspherical shape. Specifically, the first lens to the seventh lens can all adopt plastic aspherical lenses, and the aspherical lenses can effectively correct aberration, improve imaging quality and provide optical performance products with higher cost performance.

The application is further illustrated in the following examples. In various embodiments, the thickness, radius of curvature, and material selection portion of each lens in the optical lens may vary, and for specific differences, reference may be made to the parameter tables of the various embodiments. The following examples are merely preferred embodiments of the present application, but the embodiments of the present application are not limited to the following examples, and any other changes, substitutions, combinations or simplifications that do not depart from the gist of the present application are intended to be equivalent substitutes within the scope of the present application.

In various embodiments of the present application, when an aspherical lens is used as the lens, the surface shape of the aspherical lens satisfies the following equation:

；

where z is the distance sagittal height from the aspherical surface vertex when the aspherical surface is at a position of height h along the optical axis direction, c is the paraxial curvature of the surface, k is the conic coefficient conic, A _2i The aspherical surface profile coefficient of the 2 i-th order.

First embodiment

Referring to fig. 1, a schematic structural diagram of an optical lens 100 according to a first embodiment of the present application is shown, where the optical lens 100 includes, in order from an object side to an imaging surface S17 along an optical axis: a first lens L1, a second lens L2, a stop ST, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, and a filter G1.

The first lens element L1 has a negative refractive power, wherein an object-side surface S1 of the first lens element is concave at a paraxial region, and an image-side surface S2 of the first lens element is concave.

The second lens element L2 has positive refractive power, wherein an object-side surface S3 of the second lens element is convex, and an image-side surface S4 of the second lens element is concave.

The third lens L3 has positive optical power, and both the object side surface S5 and the image side surface S6 of the third lens are convex.

The fourth lens element L4 has negative refractive power, wherein an object-side surface S7 of the fourth lens element is convex at a paraxial region thereof and an image-side surface S8 of the fourth lens element is concave at a paraxial region thereof.

The fifth lens element L5 has negative refractive power, wherein an object-side surface S9 of the fifth lens element is concave, and an image-side surface S10 of the fifth lens element is convex.

The sixth lens element L6 has positive refractive power, wherein an object-side surface S11 of the sixth lens element is concave, and an image-side surface S12 of the sixth lens element is convex at a paraxial region.

The seventh lens L7 has negative optical power, an object-side surface S13 of the seventh lens is convex at a paraxial region, and an image-side surface S14 of the seventh lens is concave at a paraxial region.

The object side surface of the filter G1 is S15, and the image side surface is S16.

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 plastic aspheric lenses.

Specifically, the design parameters of each lens of the optical lens 100 provided in the present embodiment are shown in table 1.

TABLE 1

The surface profile coefficients of the aspherical surfaces of the optical lens 100 in this embodiment are shown in table 2.

TABLE 2

In the present embodiment, graphs of distortion, curvature of field, chromatic aberration of homeotropic axis, and chromatic aberration of axial direction of the optical lens 100 are shown in fig. 2, 3, 4, and 5, respectively.

The distortion curves in FIG. 2 represent F-Tan (θ) distortions corresponding to different fields of view on the image plane, with the abscissa representing the magnitude of the distortion and the ordinate representing the angle of view (in degrees); as can be seen from the figure, the distortion of the lens is controlled to be within ±2% in the full field of view of the lens, indicating that the distortion of the optical lens 100 is well corrected.

In fig. 3, the field Qu Quxian represents the field curvature of the meridian and sagittal directions at different image heights on the image plane, the abscissa represents the offset (unit: mm), and the ordinate represents the angle of view (unit: degree), and as can be seen from the figure, the field curvature offset of the meridian and sagittal directions on the image plane is controlled within ±0.06 mm, which indicates that the field curvature of the optical lens 100 is well corrected.

The vertical axis chromatic aberration curves in fig. 4 show chromatic aberration of different image heights of each wavelength with respect to the center wavelength on the image plane, the horizontal axis in the figure shows the vertical axis chromatic aberration value (unit: micrometers) of each wavelength with respect to the center wavelength, and the vertical axis shows the normalized field angle, and it is known that the chromatic aberration of each wavelength with respect to the center wavelength is controlled within ±2 micrometers in different fields of view, which means that the vertical axis chromatic aberration of the optical lens 100 is well corrected.

The axial chromatic aberration curve in fig. 5 shows the aberration on the optical axis at the imaging plane, the abscissa in the figure shows the offset, and the ordinate shows the normalized pupil radius, and it is understood from the figure that the axial chromatic aberration of the shortest wavelength and the maximum wavelength is controlled within ±0.03 mm, which indicates that the axial chromatic aberration of the optical lens 100 is well corrected.

Second embodiment

Referring to fig. 6, a schematic structural diagram of an optical lens 200 according to a second embodiment of the present application is shown, and the optical lens 200 according to the present embodiment is substantially the same as the optical lens 100 according to the first embodiment, and is mainly different in the radius of curvature, aspheric coefficients, thickness and material of each lens surface.

Specifically, the design parameters of the optical lens 200 provided in this embodiment are shown in table 3.

TABLE 3 Table 3

The surface profile coefficients of the aspherical surfaces of the optical lens 200 in this embodiment are shown in table 4.

TABLE 4 Table 4

Referring to fig. 7, 8, 9 and 10, there are shown graphs of distortion, curvature of field, chromatic aberration of vertical axis and chromatic aberration of axial direction of the optical lens 200, respectively, and it can be seen from fig. 7 that the optical distortion is controlled within ±2%, which indicates that the distortion of the optical lens 200 is well corrected; as can be seen from fig. 8, the curvature of field is controlled within ±0.08mm, which indicates that the curvature of field of the optical lens 200 is better corrected; it can be seen from fig. 9 that the vertical chromatic aberration at different wavelengths is controlled within ±2 micrometers, and from fig. 10 that the axial chromatic aberration at different wavelengths is controlled within ±0.03 millimeters, which means that the chromatic aberration of the optical lens 200 is well corrected; as can be seen from fig. 7, 8, 9 and 10, the optical lens 200 has good optical imaging quality.

Third embodiment

As shown in fig. 11, the optical lens 300 according to the third embodiment is provided in the present embodiment, and the optical lens 300 according to the present embodiment is substantially the same as the optical lens 100 according to the first embodiment described above, except that the radius of curvature, aspheric coefficients, thickness, and materials of the lens surfaces are different.

Specifically, the design parameters of the optical lens 300 provided in this embodiment are shown in table 5.

TABLE 5

The surface profile coefficients of the aspherical surfaces of the optical lens 300 in this embodiment are shown in table 6.

TABLE 6

Referring to fig. 12, 13, 14 and 15, the distortion, curvature of field, chromatic aberration of vertical axis and chromatic aberration of axial direction of the optical lens 300 are shown respectively, and it can be seen from fig. 12 that the optical distortion is controlled within ±2%, which indicates that the distortion of the optical lens 300 is well corrected; from fig. 13, it can be seen that the curvature of field is controlled within ±0.2mm, which indicates that the curvature of field of the optical lens 300 is better corrected; it can be seen from fig. 14 that the vertical chromatic aberration at different wavelengths is controlled within ±2 micrometers, and from fig. 15 that the axial chromatic aberration at different wavelengths is controlled within ±0.03 millimeters, which means that the chromatic aberration of the optical lens 300 is well corrected; as can be seen from fig. 12, 13, 14 and 15, the optical lens 300 has good optical imaging quality.

Fourth embodiment

Referring to fig. 16, a schematic diagram of an optical lens 400 according to a fourth embodiment of the present application is shown, and the optical lens 400 according to the present application has substantially the same structure as the optical lens 100 according to the first embodiment, except that an object-side surface S7 of the fourth lens element is concave, an image-side surface S8 of the fourth lens element is convex, and the curvature radius, aspheric coefficients, thickness, material and the like of each lens element are different.

The relevant parameters of each lens in the optical lens 400 provided in this embodiment are shown in table 7.

TABLE 7

The surface profile coefficients of the aspherical surfaces of the optical lens 400 in this embodiment are shown in table 8.

TABLE 8

Referring to fig. 17, 18, 19 and 20, there are shown graphs of distortion, curvature of field, chromatic aberration of vertical axis and chromatic aberration of axial direction of the optical lens 400, respectively, and it can be seen from fig. 17 that the optical distortion is controlled within ±2%, which indicates that the distortion of the optical lens 400 is well corrected; as can be seen from fig. 18, the curvature of field is controlled within ±0.1mm, which indicates that the curvature of field of the optical lens 400 is better corrected; it can be seen from fig. 19 that the vertical chromatic aberration at different wavelengths is controlled within ±2 micrometers, and from fig. 20 that the axial chromatic aberration at different wavelengths is controlled within ±0.03 millimeters, which means that the chromatic aberration of the optical lens 400 is well corrected; as can be seen from fig. 17, 18, 19 and 20, the optical lens 400 has good optical imaging quality.

Fifth embodiment

The schematic structure of the optical lens provided in this embodiment is substantially the same as that of the optical lens 400 in the fourth embodiment, and the difference is mainly that the radius of curvature, aspheric coefficients, thickness, material, etc. of each lens surface are different.

The relevant parameters of each lens in the optical lens provided in this embodiment are shown in table 9.

TABLE 9

The surface form coefficients of the aspherical surfaces of the optical lens in this example are shown in table 10.

Table 10

Referring to fig. 21, 22, 23 and 24, there are shown graphs of distortion, curvature of field, chromatic aberration of vertical axis and chromatic aberration of axial direction of the optical lens provided in this embodiment, respectively, and it can be seen from fig. 21 that the optical distortion is controlled within ±2%, which indicates that the distortion of the optical lens in this embodiment is well corrected; as can be seen from fig. 22, the curvature of field is controlled within ±0.15mm, which indicates that the curvature of field of the optical lens in this embodiment is better corrected; as can be seen from fig. 23, the vertical chromatic aberration at different wavelengths is controlled within ±2 micrometers, and as can be seen from fig. 24, the axial chromatic aberration at different wavelengths is controlled within ±0.03 millimeters, which means that the chromatic aberration of the optical lens in this embodiment is well corrected; as can be seen from fig. 21, 22, 23 and 24, the optical lens provided in this embodiment has good optical imaging quality.

Sixth embodiment

The schematic structure of the optical lens provided in this embodiment is substantially the same as that of the optical lens 400 in the fourth embodiment, and is different from the fourth embodiment in that the radius of curvature, aspheric coefficients, thicknesses, materials, and the like of the lens surfaces are different.

The relevant parameters of each lens in the optical lens in this embodiment are shown in table 11.

TABLE 11

The surface form coefficients of the aspherical surfaces of the optical lens in this example are shown in table 12.

Table 12

Referring to fig. 25, 26, 27 and 28, there are shown graphs of distortion, curvature of field, chromatic aberration of vertical axis and chromatic aberration of axial direction of the optical lens provided in this embodiment, respectively, and it can be seen from fig. 25 that the optical distortion is controlled within ±2%, which indicates that the distortion of the optical lens in this embodiment is well corrected; as can be seen from fig. 26, the curvature of field is controlled within ±0.12mm, which indicates that the curvature of field of the optical lens in this embodiment is better corrected; as can be seen from fig. 27, the vertical chromatic aberration at different wavelengths is controlled within ±2 micrometers, and as can be seen from fig. 28, the axial chromatic aberration at different wavelengths is controlled within ±0.03 millimeters, which means that the chromatic aberration of the optical lens in this embodiment is well corrected; as can be seen from fig. 25, 26, 27 and 28, the optical lens provided in this embodiment has good optical imaging quality.

Referring to table 13, the optical characteristics of the optical lens provided in the above six embodiments, including the effective focal length f, the total optical length TTL, the maximum field angle FOV, the image height IH corresponding to the maximum field angle, and the correlation values corresponding to each of the foregoing conditional expressions, are shown.

TABLE 13

In summary, the optical lens provided by the embodiment of the application has at least the following advantages:

(1) The optical lens provided by the application has reasonable arrangement of the lens surface and the focal power, so that the lens has a larger field angle (FOV >110 degrees), and smaller distortion and smaller chromatic aberration, the optical distortion of the lens can be controlled within +/-2%, the resolution of the lens and the degree of restoration of image details can be improved, the resolving power of the lens can be improved, and the requirements of wide field of view and small distortion can be better met.

(2) The optical lens provided by the application adopts seven lenses with specific focal power, and has the characteristics of compact structure and high pixels through specific surface shape collocation and reasonable focal power distribution, and can be compatible with 50MP and 108MP large target surface sensor chips to realize ultra-high definition imaging.

(3) The optical lens provided by the application can enlarge the light incoming quantity of the system and reduce the depth of field during shooting by reasonably configuring the size of the lens aperture, thereby ensuring the imaging quality of the system in a darker environment, effectively blurring the background and highlighting the focusing main body during shooting, and better meeting the use requirement of the portrait shooting of the portable electronic equipment.

In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present application. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The above examples merely represent a few embodiments of the present application, which are described in more detail and are not to be construed as limiting the scope of the present application. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the application, which are all within the scope of the application. Accordingly, the scope of the application should be assessed as that of the appended claims.

Claims

1. An optical lens comprising, in order from an object side to an imaging surface along an optical axis:

a first lens element with negative refractive power having a concave object-side surface at a paraxial region and a concave image-side surface;

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

a third lens having positive optical power, both the object-side surface and the image-side surface of which are convex;

a fourth lens having negative optical power;

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

a sixth lens element with positive refractive power having a concave object-side surface and a convex image-side surface at a paraxial region;

a seventh lens element with negative refractive power having an object-side surface being convex at a paraxial region and an image-side surface being concave at a paraxial region;

wherein, the optical lens satisfies the conditional expression: 1.8< TTL/f <2.3,3< f4/f7<8, TTL indicating the total optical length of the optical lens, f indicating the effective focal length of the optical lens, f4 indicating the focal length of the fourth lens, and f7 indicating the focal length of the seventh lens.

2. The optical lens according to claim 1, wherein the optical lens satisfies a conditional expression: -3< f1/f < -1, -6< R11/R12< -2, wherein f1 represents a focal length of the first lens, R11 represents a radius of curvature of an object side of the first lens, and R12 represents a radius of curvature of an image side of the first lens.

3. The optical lens according to claim 1, wherein the optical lens satisfies a conditional expression: 2< f2/f <3,0.7< R21/R22<1.15, wherein f2 represents a focal length of the second lens, R21 represents a radius of curvature of an object side of the second lens, and R22 represents a radius of curvature of an image side of the second lens.

4. The optical lens according to claim 1, wherein the optical lens satisfies a conditional expression: 0.9< f3/f <1.5, -3.5< R31/R32< -1 >, wherein f3 represents a focal length of the third lens, R31 represents a radius of curvature of an object side of the third lens, and R32 represents a radius of curvature of an image side of the third lens.

5. The optical lens according to claim 1, wherein the optical lens satisfies a conditional expression: -1.2< f1/f2< -0.7,1.8< R12/R22<5, wherein f1 represents the focal length of the first lens, f2 represents the focal length of the second lens, R12 represents the radius of curvature of the image side of the first lens, and R22 represents the radius of curvature of the image side of the second lens.

6. The optical lens according to claim 1, wherein the optical lens satisfies a conditional expression: 0.85< f3/f6<1.6, wherein f3 represents a focal length of the third lens and f6 represents a focal length of the sixth lens.

7. The optical lens according to claim 1, wherein the optical lens satisfies a conditional expression: -100< R61/f < -1, R61/R62>2, wherein R61 represents a radius of curvature of an object-side surface of the sixth lens, and R62 represents a radius of curvature of an image-side surface of the sixth lens.

8. The optical lens according to claim 1, wherein the optical lens satisfies a conditional expression: 0.9< CT1/CT2<1.35, wherein CT1 represents a center thickness of the first lens and CT2 represents a center thickness of the second lens.

9. The optical lens according to claim 1, wherein the optical lens satisfies a conditional expression: 0.38< ET6/CT6<0.45, wherein ET6 represents an edge thickness of the sixth lens and CT6 represents a center thickness of the sixth lens.

10. The optical lens according to claim 1, wherein the optical lens satisfies a conditional expression: 0.5< DM6/DM7<0.62, -2.5< R62/R72< -0.5, wherein DM6 represents the maximum effective aperture of the sixth lens, DM7 represents the maximum effective aperture of the seventh lens, R62 represents the radius of curvature of the image side of the sixth lens, and R72 represents the radius of curvature of the image side of the seventh lens.

11. The optical lens according to claim 1, wherein the optical lens satisfies a conditional expression: 2.8< IH/f <3.2,5.0mm < IH/FNo <5.5mm, wherein IH represents the image height corresponding to the maximum field angle of the optical lens, and FNo represents the aperture value of the optical lens.