CN116500766A

CN116500766A - Optical lens

Info

Publication number: CN116500766A
Application number: CN202310785807.XA
Authority: CN
Inventors: 钟培森; 谢雨辰; 章彬炜
Original assignee: Jiangxi Lianyi Optics Co Ltd
Current assignee: Jiangxi Lianyi Optics Co Ltd
Priority date: 2023-06-30
Filing date: 2023-06-30
Publication date: 2023-07-28
Anticipated expiration: 2043-06-30
Also published as: CN116500766B

Abstract

The invention 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 an object-side surface being concave at a paraxial region and an image-side surface being convex at a paraxial region; a second lens element with negative refractive power having a convex object-side surface and a concave image-side surface; the object side surface of the third lens is a convex surface, and the image side surface of the third lens is a convex surface; a fourth lens element with positive refractive power having a concave object-side surface and a convex image-side surface; a fifth lens element with positive refractive power having a concave object-side surface and a convex image-side surface; the sixth lens element with negative refractive power has a convex object-side surface at a paraxial region and a concave image-side surface at a paraxial region. The optical lens has the advantages of wide viewing angle, small distortion, large aperture and large image plane through specific surface type collocation and focal power combination, and can better adapt to the development trend of portable electronic equipment.

Description

Optical lens

Technical Field

The invention 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, consumers have higher requirements on the shooting function of the mobile phones, and the main development trend of the mobile phone lens is that ultra-high pixels, wide angles and light and thin, so that higher requirements are put on the shooting lens carried on the portable electronic equipment. In order to pursue high-quality imaging, currently, all plastic lenses are mostly adopted in the main-stream mobile phone lens, and the number of lenses is increased from 5-6 lenses to 7-8 lenses for correcting the optical path, but the lenses are limited by factors such as light and thin mobile phones, light transmittance of the plastic lenses, assembly precision and the like, the number of the plastic lenses is difficult to further increase, and the all plastic lenses meet the bottleneck period. Meanwhile, the wide-angle camera gradually becomes the standard of flagship machines of all main stream mobile phone manufacturers so as to meet the shooting requirement of 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

Therefore, the invention aims to provide an optical lens which has at least the advantages of wide viewing angle, large aperture, small distortion and large image plane and can better adapt to the development trend of portable electronic equipment.

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

The invention provides an optical lens, which sequentially comprises from an object side to an imaging surface along an optical axis: a first lens having negative optical power, an object-side surface of the first lens being concave at a paraxial region and an image-side surface of the first lens being convex at the paraxial region; a second lens with negative focal power, wherein the object side surface of the second lens is a convex surface, and the image side surface of the second lens is a concave surface; a third lens with positive focal power, wherein the object side surface of the third lens is a convex surface, and the image side surface of the third lens is a convex surface; a fourth lens element with positive refractive power, wherein the object-side surface of the fourth lens element is concave and the image-side surface of the fourth lens element is convex; a fifth lens with positive focal power, wherein an object side surface of the fifth lens is a concave surface, and an image side surface of the fifth lens is a convex surface; a sixth lens element with negative refractive power having a convex object-side surface at a paraxial region and a concave image-side surface at a paraxial region; wherein, the optical lens satisfies the conditional expression: 0.01< f3/f4<0.1, f3 denotes a focal length of the third lens, and f4 denotes a focal length of the fourth lens.

Compared with the prior art, the optical lens provided by the invention adopts six lenses with specific shape and focal power, and the optical lens has the characteristics of high pixels and wide angles through reasonable collocation of the glass lenses and the plastic lenses, and can be matched with a 50MP (Megapixel) sensor chip to realize ultra-high definition imaging; meanwhile, as the surface type and focal power of each lens are reasonably matched, the lens has the characteristics of a compact structure and a large aperture, and more luminous flux can enter the lens system, so that the lens can be imaged clearly in a dim environment, and the development trend of portable electronic equipment is better adapted.

Drawings

The foregoing and/or additional aspects and advantages of the invention 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 invention.

Fig. 2 is a graph showing a field curvature of an optical lens according to a first embodiment of the present invention.

Fig. 3 is a graph showing f-tan θ distortion of an optical lens according to a first embodiment of the present invention.

Fig. 4 is an axial chromatic aberration diagram of an optical lens according to a first embodiment of the present invention.

Fig. 5 is a vertical axis chromatic aberration diagram of an optical lens according to a first embodiment of the present invention.

Fig. 6 is a field curvature chart of an optical lens according to a second embodiment of the present invention.

Fig. 7 is a graph showing f-tan θ distortion of an optical lens according to a second embodiment of the present invention.

Fig. 8 is an axial chromatic aberration diagram of an optical lens according to a second embodiment of the present invention.

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

Fig. 10 is a field curve diagram of an optical lens according to a third embodiment of the present invention.

Fig. 11 is a graph showing f-tan θ distortion of an optical lens according to a third embodiment of the present invention.

Fig. 12 is an axial chromatic aberration chart of an optical lens according to a third embodiment of the present invention.

Fig. 13 is a vertical axis chromatic aberration diagram of an optical lens according to a third embodiment of the present invention.

Detailed Description

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

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 of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. 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 invention provides an optical lens, which sequentially comprises from an object side to an imaging surface along an optical axis: a first lens, a second lens, a diaphragm, a third lens, a fourth lens, a fifth lens, a sixth lens and an optical filter.

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

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

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

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

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

A sixth lens element with negative optical power, wherein the object-side surface of the sixth lens element is convex at a paraxial region and the image-side surface of the sixth lens element is concave at a paraxial region.

Wherein, at least one plastic lens and one glass lens are contained in the optical lens. Compared with a plastic lens, the glass lens has the advantages of smaller dispersion coefficient, better light transmittance, stronger stability and the like, and can greatly reduce the problems of glare, ghosting and the like, and the glass-plastic mixed lens combines the advantages of a glass lens and a plastic lens, can reduce the thickness and the distortion ratio of the lens, and can improve the imaging definition and the aperture size.

According to the invention, through the mixing and collocation of glass and plastic lenses and the reasonable constraint of the surface and focal power of each lens, the structure is compact, and the lens has high imaging quality and large aperture, so that the miniaturization of the lens and the reasonable balance of high pixels are better realized.

In some embodiments, the optical lens satisfies the following conditional expression: 0.01< f3/f4<0.1, f3 denotes a focal length of the third lens, and f4 denotes a focal length of the fourth lens. The optical power distribution of the third lens and the fourth lens is reasonably arranged, so that the converging of marginal view field rays is facilitated, the converged rays smoothly enter the rear-end optical system, the smooth transition of the ray trend is further realized, the correction difficulty of distortion and aberration is reduced, and the imaging quality of the optical lens is improved.

In some embodiments, the optical lens satisfies the following conditional expression: -30< f1/f < -11, wherein f1 represents the focal length of the first lens and f represents the effective focal length of the optical lens. The first lens has smaller negative focal power, can slow down the deflection degree of incident light, is favorable for entering an optical system by light rays in a larger range, is favorable for expanding the field angle of the lens, realizes the large aperture characteristic of the lens, is favorable for the optical lens to acquire more scene information, meets the requirement of large-range shooting, and is favorable for improving the problem of quick reduction of the relative brightness 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: -30< f2/f < -20,0.6< R3/R4<1.5, wherein f2 represents the focal length of the second lens, f represents the effective focal length of the optical lens, R3 represents the radius of curvature of the object side of the second lens, and R4 represents the radius of curvature of the image side of the second lens. The lens has the advantages that the 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 edge view field is reduced while the view field angle is increased, the lens has smaller distortion, and meanwhile, the spherical aberration generated by the second lens can be effectively balanced, and the overall imaging quality is improved.

In some embodiments, the optical lens satisfies the following conditional expression: 1< f3/f <2, -2< R5/R6< -0.9, wherein f3 represents a focal length of the third lens, f represents an effective focal length of the optical lens, R5 represents a radius of curvature of an object side surface of the third lens, and R6 represents a radius of curvature of an image side surface of the third lens. The third lens has proper positive focal power and surface shape, and can make the trend transition after light convergence stable, thereby improving the imaging quality of the optical lens.

In some embodiments, the optical lens satisfies the following conditional expression: 20< f4/f <30,0.5< R7/R8<1.3, wherein f4 represents a focal length of the fourth lens, f represents an effective focal length of the optical lens, R7 represents a radius of curvature of an object side surface of the fourth lens, and R8 represents a radius of curvature of an image side surface of the fourth lens. The fourth lens has proper positive focal power and surface shape, can effectively correct the distortion of the lens at a large angle of view, enables the lens to have smaller distortion, improves the imaging quality, and can be used as an intermediate lens of an optical system to intermediately correct the aberration of each lens of the object side due to the eccentric difference and reduce the correction pressure of a rear lens group, namely, the eccentric sensitivity can be reduced, so that the astigmatism of each lens of the object side due to the eccentric is suppressed, and the imaging resolution is further improved.

In some embodiments, the optical lens satisfies the following conditional expression: 0.5< f5/f <1,2< R9/R10<5, wherein f5 represents a focal length of the fifth lens, f represents an effective focal length of the optical lens, R9 represents a radius of curvature of an object side surface of the fifth lens, and R10 represents a radius of curvature of an image side surface of the fifth lens. The fifth lens has proper positive focal power and surface shape, is favorable for converging marginal rays, enables the converged rays to smoothly enter the rear-end optical system, further enables the rays to stably transition in trend, reduces the correction difficulty of distortion and aberration, and further improves the imaging quality of the optical lens.

In some embodiments, the optical lens satisfies the following conditional expression: -1< f6/f < -0.5,2< R11/R12<7, wherein f6 represents a focal length of the sixth lens, f represents an effective focal length of the optical lens, R11 represents a radius of curvature of an object side of the sixth lens, and R12 represents a radius of curvature of an image side of the sixth lens. The focal length of the sixth lens and the surface shape of the near optical axis of each surface can be reasonably adjusted to reduce the shape change of the sixth lens, reduce the generation of stray light, reasonably control the light trend, increase the incident angle of light entering the image surface, realize a large image surface, and simultaneously avoid the problem of overhigh lens sensitivity caused by overlarge light deflection degree.

In some embodiments, the optical lens satisfies the following conditional expression: 0.1< R1/R2<1, -15< R2/f < -1 >, wherein f represents an effective focal length of the optical lens, R1 represents a radius of curvature of an object side surface of the first lens, and R2 represents a radius of curvature of an image side surface of the first lens. The above conditions are met, the surface type of the first lens is reasonably arranged, the change degree of the refraction angle of incident light is reduced, excessive aberration caused by excessively strong refraction change is avoided, more light rays enter the rear optical system, and the whole imaging quality is improved while the view angle of the lens is increased.

In some embodiments, the optical lens satisfies the following conditional expression: IH/FNo >6.5mm, wherein IH represents the image height corresponding to the full field angle of the optical lens, and FNo represents the f-number of the optical lens. The lens has larger image surface and larger aperture, the luminous flux entering the lens is increased to a certain extent, the influence of noise generated when light is insufficient on an imaging picture is reduced, and the lens still has excellent imaging effect in dark night environment, so that the imaging requirement of bright and dark environment can be met.

In some embodiments, the optical lens satisfies the following conditional expression: 2.5< IH/f <3, wherein IH represents an image height corresponding to a full field angle of the optical lens, and f represents an effective focal length 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: 3.5mm < (Nd 2/Nd 3) ×f <4.0mm, where f represents the effective focal length of the optical lens, nd2 represents the refractive index of the second lens, and Nd3 represents the refractive index of the third lens. The second lens and the third lens can be matched with each other by adopting a reasonable refractive index, so that chromatic aberration and distortion of the lens can be effectively balanced, and the requirement of small distortion of the lens is met.

In some embodiments, the optical lens satisfies the following conditional expression: 0.7< TTL/IH <0.8, wherein TTL represents the total optical length of the optical lens, and IH represents the image height corresponding to the full field angle of the optical lens. The imaging device meets the conditions, can realize large target surface imaging of the optical lens, improves the pixel point size under the same pixel, and can improve the energy receiving efficiency of the chip to the light collected by the lens, thereby improving the imaging quality and simultaneously maintaining the miniaturization of the lens.

In some embodiments, the optical lens satisfies the following conditional expression: 0.45< f1/f2<0.65, wherein f1 represents a focal length of the first lens and f2 represents a focal length of the second lens. The lens has the advantages that the conditions are met, the light rays of the lens are excessively gentle, the control of the distortion of the lens is facilitated, and the lens meets the requirements of a large aperture and a wide viewing angle and has smaller distortion.

In some embodiments, the optical lens satisfies the following conditional expression: -1.3< (sag41+sag42)/ET 4< -1.1, wherein SAG41 represents the sagittal height of the object side of the fourth lens, SAG42 represents the sagittal height of the image side of the fourth lens, ET4 represents the edge thickness of the fourth lens. The method meets the conditions, is favorable for better modifying field curvature and spherical aberration, can slow down the shape change of the fourth lens, and reduces the processing difficulty of the fourth lens.

In some embodiments, the optical lens satisfies the following conditional expression: 0.25< CT56/TTL <0.33,1.2< (CT 5+ CT 6)/(ET 5+ ET 6) <1.3, wherein CT56 represents a separation distance of the fifth lens and the sixth lens on the optical axis, TTL represents an optical total length of the optical lens, CT5 represents a center thickness of the fifth lens, CT6 represents a center thickness of the sixth lens, ET5 represents an edge thickness of the fifth lens, and ET6 represents an edge thickness of the sixth lens. The center thicknesses of the fifth lens and the sixth lens and the interval distance between the lenses can be reasonably distributed, and the light distribution is adjusted, so that the compactness and miniaturization of the optical lens structure are facilitated.

As an implementation mode, the six-piece glass-plastic mixed matching structure is adopted, so that the lens can be better matched with a large target surface chip to realize high-definition imaging, and meanwhile, the reasonable balance of large aperture, miniaturization and large wide angle of the lens can be realized. Specifically, the third lens can be a glass aspheric lens, the first lens, the second lens, the fourth lens, the fifth lens and the sixth lens are plastic aspheric lenses, and the aspheric lens can effectively reduce cost, correct aberration and provide an optical performance product with higher cost performance. It should be noted that other matching combinations of the glass-plastic mixed lenses can also meet the requirements, and the selection can be specifically made according to the requirements.

The invention 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 invention, but the embodiments of the present invention 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 invention are intended to be equivalent substitutes within the scope of the present invention.

In various embodiments of the present invention, 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 in the optical axis direction, c is the paraxial curvature of the surface, k is the quadric coefficient, 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 invention is shown, where the optical lens 100 includes, in order from an object side to an imaging surface S15 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, 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 thereof, and an image-side surface S2 of the first lens element is convex at a paraxial region thereof.

The second lens element L2 has negative 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 element L3 has positive refractive power, wherein an object-side surface S5 of the third lens element is convex, and an image-side surface S6 of the third lens element is convex.

The fourth lens element L4 has positive refractive power, wherein an object-side surface S7 of the fourth lens element is concave, and an image-side surface S8 of the fourth lens element is convex.

The fifth lens element L5 has positive 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 negative refractive power, wherein an object-side surface S11 of the sixth lens element is convex at a paraxial region thereof and an image-side surface S12 of the sixth lens element is concave at a paraxial region thereof.

The object side surface of the filter G1 is S13, and the image side surface is S14.

The first lens L1, the second lens L2, the fourth lens L4, the fifth lens L5 and the sixth lens L6 are all plastic aspherical lenses, and the third lens L3 is a glass aspherical lens.

Specifically, the design parameters of each lens of the optical lens 100 provided in this 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

Referring to fig. 2 to 5, a field curvature curve graph, a distortion curve graph, an axial chromatic aberration curve graph, and a vertical chromatic aberration curve graph of the optical lens 100 are shown.

The field curvature curve of fig. 2 shows the degree of curvature of the meridional image plane and the sagittal image plane, and in the figure, the horizontal axis shows the amount of shift (in mm) and the vertical axis shows the angle of view (in degrees). As can be seen from the figure, the curvature of field of the meridional image plane and the sagittal image plane are controlled within ±0.2 millimeters, which indicates that the curvature of field of the optical lens 100 is well corrected.

The distortion curves of fig. 3 represent distortion at different image heights on the imaging plane, with the horizontal axis representing the percent distortion and the vertical axis representing the angle of view (in degrees). As can be seen from the figure, the optical distortion at different image heights on the imaging plane is controlled within ±1.5%, which means that the optical distortion of the optical lens 100 is well corrected.

The axial chromatic aberration curve of fig. 4 represents aberration on the optical axis at the imaging plane, in which the horizontal axis represents a sphere value (unit: mm) and the vertical axis represents a normalized pupil radius. As can be seen from the figure, the axial chromatic aberration is controlled within ±0.03mm, which means that the axial chromatic aberration of the optical lens 100 is well corrected.

The vertical axis color difference curve of fig. 5 shows the color difference between the longest wavelength and the shortest wavelength at different image heights on the imaging plane, in which the horizontal axis shows the vertical axis color difference value (unit: micrometers) of each wavelength with respect to the center wavelength, and the vertical axis shows the normalized field angle. As can be seen from the figure, the vertical chromatic aberration of each wavelength with respect to the center wavelength in different fields of view is controlled within ±2 micrometers, indicating that the vertical chromatic aberration of the optical lens 100 is well corrected.

Second embodiment

The optical lens provided in this embodiment is substantially the same as the optical lens 100 in the first embodiment in that the difference is mainly in the radius of curvature, aspherical coefficient, thickness, and the like of each lens face.

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

TABLE 3 Table 3

The surface form coefficients of the aspherical surfaces of the optical lens in this example are shown in table 4.

TABLE 4 Table 4

Referring to fig. 6, 7, 8 and 9, graphs of curvature of field, distortion, axial chromatic aberration and vertical chromatic aberration of the optical lens in the present embodiment are shown. From fig. 6, it can be seen that the curvature of field is controlled within ±0.2 mm, which indicates that the curvature of field of the optical lens is better corrected. As can be seen from fig. 7, the optical distortion is controlled within ±1.5%, indicating that the distortion of the optical lens is well corrected. It can be seen from fig. 8 that the axial chromatic aberration of the shortest wavelength and the maximum wavelength is controlled within ±0.03mm, which indicates that the axial chromatic aberration of the optical lens is well corrected. As can be seen from fig. 9, the vertical chromatic aberration at different wavelengths is controlled within ±2 microns, indicating that the vertical chromatic aberration of the optical lens is well corrected. It can be seen from fig. 6 to 9 that the aberration of the optical lens is well balanced, and good optical imaging quality is achieved.

Third embodiment

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

TABLE 5

The surface form coefficients of the aspherical surfaces of the optical lens in this example are shown in table 6.

TABLE 6

Referring to fig. 10, 11, 12 and 13, graphs of curvature of field, distortion, axial chromatic aberration and vertical chromatic aberration of the optical lens in the present embodiment are shown. From fig. 10, it can be seen that the curvature of field is controlled within ±0.2 mm, which indicates that the curvature of field of the optical lens is better corrected. As can be seen from fig. 11, the optical distortion is controlled within ±1.5%, indicating that the distortion of the optical lens is well corrected. It can be seen from fig. 12 that the axial chromatic aberration of the shortest wavelength and the maximum wavelength is controlled within ±0.03mm, which indicates that the axial chromatic aberration of the optical lens is well corrected. As can be seen from fig. 13, the paraxial chromatic aberration at different wavelengths is controlled within ±2 microns, indicating that the paraxial chromatic aberration of the optical lens is well corrected. It can be seen from fig. 10 to 13 that the aberration of the optical lens is well balanced, and good optical imaging quality is achieved.

Referring to table 7, the optical characteristics of the optical lens provided in the above five embodiments, respectively, include the angle of view FOV, the total optical length TTL, the image height IH, the effective focal length f, the aperture value Fno, and the correlation value corresponding to each of the above conditional expressions.

TABLE 7

In summary, the glass-plastic mixed optical lens provided by the invention has at least the following advantages:

(1) The balance between high pixel and miniaturization can be realized. The glass has better light transmittance, lower dispersion coefficient and better light transmittance and optical performance, so that the balance of high pixels and miniaturization of the lens is realized.

(2) More layers of coating optimization can be realized. At present, a high-temperature process is mostly adopted for coating the plastic lens, and the plastic lens is more likely to deform under the process, so that the yield is lower, and the coating is usually not more than 5 layers; the glass lens has strong high temperature resistance, can realize that more layers of coating films are used for controlling reflection and dazzling light, and further improves the optical imaging quality.

(3) The performance of large aperture and wide viewing angle can be realized. Because the lens shape and the diaphragm position are reasonably arranged, the large aperture characteristic of the lens is realized while the field angle of the optical lens is enlarged, the wide angle characteristic is realized, the optical lens is favorable for acquiring more scene information, the requirement of large-range shooting is met, the problem that the relative brightness of the edge field of view brought by the wide angle is fast to be improved is favorable for realizing the large aperture characteristic, and therefore, more scene information is also favorable for being acquired.

In summary, the optical lens provided by the invention adopts six lenses with specific shape and focal power, and the optical lens has the characteristics of high pixels and wide angle through reasonable collocation of the glass lenses and the plastic lenses, so that the optical lens can be matched with a 50MP sensor chip to realize ultra-high definition imaging; meanwhile, as the surface type and focal power of each lens are reasonably matched, the lens has the characteristics of a compact structure and a large aperture, and more luminous flux can enter the lens system, so that the lens can be imaged clearly in a dim environment, and the development trend of portable electronic equipment is better adapted.

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 invention. 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 invention, which are described in more detail and are not to be construed as limiting the scope of the present invention. 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 invention, which are all within the scope of the invention. Accordingly, the scope of the invention 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 having negative optical power, an object-side surface of the first lens being concave at a paraxial region and an image-side surface of the first lens being convex at the paraxial region;

a second lens with negative focal power, wherein the object side surface of the second lens is a convex surface, and the image side surface of the second lens is a concave surface;

a third lens with positive focal power, wherein the object side surface of the third lens is a convex surface, and the image side surface of the third lens is a convex surface;

a fourth lens element with positive refractive power, wherein the object-side surface of the fourth lens element is concave and the image-side surface of the fourth lens element is convex;

a fifth lens with positive focal power, wherein an object side surface of the fifth lens is a concave surface, and an image side surface of the fifth lens is a convex surface;

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

wherein, the optical lens satisfies the conditional expression: 0.01< f3/f4<0.1, f3 denotes a focal length of the third lens, and f4 denotes a focal length of the fourth lens.

2. The optical lens according to claim 1, wherein the optical lens satisfies a conditional expression: -30< f1/f < -11, wherein f1 represents the focal length of the first lens and f represents the effective focal length of the optical lens.

3. The optical lens according to claim 1, wherein the optical lens satisfies a conditional expression: -30< f2/f < -20, wherein f2 represents the focal length of the second lens and f represents the effective focal length of the optical lens.

4. The optical lens according to claim 1, wherein the optical lens satisfies a conditional expression: 1< f3/f <2, wherein f3 represents a focal length of the third lens and f represents an effective focal length of the optical lens.

5. The optical lens according to claim 1, wherein the optical lens satisfies a conditional expression: 20< f4/f <30, wherein f4 represents a focal length of the fourth lens and f represents an effective focal length of the optical lens.

6. The optical lens according to claim 1, wherein the optical lens satisfies a conditional expression: 0.5< f5/f <1,2< R9/R10<5, wherein f5 represents a focal length of the fifth lens, f represents an effective focal length of the optical lens, R9 represents a radius of curvature of an object side surface of the fifth lens, and R10 represents a radius of curvature of an image side surface of the fifth lens.

7. The optical lens according to claim 1, wherein the optical lens satisfies a conditional expression: -1< f6/f < -0.5,2< R11/R12<7, wherein f6 represents a focal length of the sixth lens, f represents an effective focal length of the optical lens, R11 represents a radius of curvature of an object side of the sixth lens, and R12 represents a radius of curvature of an image side of the sixth lens.

8. The optical lens according to claim 1, wherein the optical lens satisfies a conditional expression: 0.1< R1/R2<1, -15< R2/f < -1 >, wherein f represents an effective focal length of the optical lens, R1 represents a radius of curvature of an object side surface of the first lens, and R2 represents a radius of curvature of an image side surface of the first lens.

9. The optical lens according to claim 1, wherein the optical lens satisfies a conditional expression: 0.6< R3/R4<1.5, -2< R5/R6< -0.9, wherein R3 represents a radius of curvature of an object side surface of the second lens, R4 represents a radius of curvature of an image side surface of the second lens, R5 represents a radius of curvature of an object side surface of the third lens, and R6 represents a radius of curvature of an image side surface of the third lens.

10. The optical lens according to claim 1, wherein the optical lens satisfies a conditional expression: 0.5< R7/R8<1.3, wherein R7 represents a radius of curvature of an object side surface of the fourth lens, and R8 represents a radius of curvature of an image side surface of the fourth lens.

11. The optical lens according to claim 1, wherein the optical lens satisfies a conditional expression: IH/FNo >6.5mm, wherein IH represents the image height corresponding to the full field angle of the optical lens, and FNo represents the f-number of the optical lens.