CN113484996B

CN113484996B - Optical lens

Info

Publication number: CN113484996B
Application number: CN202111041008.9A
Authority: CN
Inventors: 章彬炜; 熊儒韬; 曾昊杰; 曾吉勇
Original assignee: Jiangxi Lianyi Optics Co Ltd
Current assignee: Jiangxi Lianyi Optics Co Ltd
Priority date: 2021-09-07
Filing date: 2021-09-07
Publication date: 2021-11-26
Anticipated expiration: 2041-09-07
Also published as: CN113484996A

Abstract

The invention provides an optical lens, which comprises six lenses in total and sequentially comprises the following components from an object side to an image side along an optical axis: a diaphragm; the first lens with positive focal power has a convex object-side surface and a concave image-side surface; a second lens having a refractive power, an image-side surface of which is concave; a third lens having a focal power, an object side surface of which is convex at a paraxial region; a fourth lens having a focal power, wherein 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; a fifth lens having positive optical power, an object-side surface of which is convex at a paraxial region; a sixth lens element with negative optical power, having a concave object-side surface at a paraxial region and a concave image-side surface at a paraxial region; and (3) a filter. The optical lens provided by the invention has the advantages that the surface type, the focal power and the placement position of each lens are reasonably matched, so that the structure is compact, the miniaturization and high pixel balance of the large-aperture lens are realized, and the shooting experience of a user is well improved.

Description

Optical lens

Technical Field

The invention relates to the technical field of molding equipment, in particular to an optical lens.

Background

At present, with the rapid development of portable electronic products, people's daily life is greatly facilitated, and the effect of watching the images at close distance from each other can be realized like being personally on the scene even if the images are separated by thousands of miles.

However, with the continuous updating and development of mobile information technology, electronic devices such as smart phones are developing in the directions of being light, thin, high-definition, full-screen, and the like, which makes the requirements for the image quality of the optical lens continuously increase, and the optical lens is miniaturized. At present, due to the enthusiasm of consumers for the hand photographing technology, most manufacturers in the market make the overall size of the optical lens larger in order to pursue high pixels, so that most rear cameras of mobile phones are a part of lenses which protrude greatly, and the development trend of being light and thin is not met at all, and mainly due to the fact that the pursuit of the high pixels of the optical lens and the thickness of the lens are mutually influenced.

Disclosure of Invention

Based on this, the present invention aims to provide an optical lens for solving the above problems.

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

in a first aspect, the present invention provides an optical lens, which includes six lenses, in order from an object side to an image side along an optical axis:

a diaphragm;

the first lens with positive focal power has a convex object-side surface and a concave image-side surface;

a second lens having a refractive power, an image-side surface of which is concave;

a third lens having a focal power, an object side surface of which is convex at a paraxial region;

a fourth lens having a focal power, wherein 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;

a fifth lens having positive optical power, an object-side surface of which is convex at a paraxial region;

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

half of the diagonal length ImgH of the effective pixel area on the imaging surface of the optical lens and the total optical length TTL of the optical lens satisfy: imgH/TTL is more than 0.7 and less than 0.8;

the aperture diameter DT of the optical lens and the diameter D31 of the object side light through hole of the third lens meet the following conditions: DT/D31 is more than 1.1 and less than 1.3;

and the center thickness CT3 of the third lens and the air interval T34 of the third lens and the fourth lens on the optical axis satisfy the following conditional expression: 0.3 < CT3/T34 < 1.9.

Further, SAGs 41j at a distance j mm from the object side optical axis of the fourth lens and SAGs 41i at a distance i mm from the object side optical axis of the fourth lens and SAGs 42j at a distance j mm from the image side optical axis of the fourth lens and SAGs 42i at a distance imm from the image side optical axis of the fourth lens satisfy SAGs 41j-SAG41i < 0, SAG42j-SAG42i < 0, j = i + 0.1.

Further, the inclination angle θ 32 of the edge surface of the image side surface of the third lens and the inclination angle θ 31 of the edge surface of the object side surface of the third lens satisfy: 1.8 < theta 32/theta 31 < 2.2.

Further, the effective half aperture DM11 of the object side surface of the first lens and the effective half aperture DM32 of the image side surface of the third lens satisfy: DM32/DM11 is more than 0.9 and less than 1.1.

Further, the effective aperture diameter D of the optical lens and the effective focal length f of the optical lens satisfy: f/D is more than 5.0 and less than 5.5.

Further, the focal length f1 of the first lens and the focal length f3 of the third lens satisfy: -0.04 < f1/f3 < 0.17.

Further, the focal length f1 of the first lens, the focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: 1.2 < (1/f1-1/f3)/(1/f) < 1.6.

Further, the aperture diameter DT of the optical lens and a half ImgH of a diagonal length of an effective pixel area on an imaging surface of the optical lens satisfy: 0.58 < DT/ImgH < 0.61.

Further, a curvature radius R32 of the image-side surface of the third lens element, a curvature radius R11 of the object-side surface of the first lens element, and a stop aperture DT of the optical lens satisfy: 1.1 < (1/R11-1/R32). times.DT < 1.6.

Further, the central thickness CT4 of the fourth lens and the central thickness CT5 of the fifth lens satisfy the following conditional expression: 0.8 < CT4/CT5 < 2.4.

Further, the central thickness CT4 of the fourth lens and the air interval T34 of the third lens and the fourth lens on the optical axis satisfy the following conditional expression: 0.5 < CT4/T34 < 5.6.

Compared with the prior art, the optical lens provided by the embodiment of the invention has the advantages that the lens shapes and focal powers of the six lenses with the specific focal powers are reasonably matched, so that the high-pixel requirement is met, the structures of the lenses are more compact, the high-definition imaging effect is well realized, the miniaturization of the lens is also ensured, and the shooting experience of a user can be effectively improved.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a schematic structural diagram of an optical lens system according to a first embodiment of the present invention;

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

FIG. 3 is a diagram illustrating a distortion curve of an optical lens according to a first embodiment of the present invention;

FIG. 4 is a graph illustrating axial chromatic aberration 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 schematic structural diagram of an optical lens system according to a second embodiment of the present invention;

FIG. 7 is a field curvature graph of an optical lens according to a second embodiment of the present invention;

FIG. 8 is a distortion graph of an optical lens in a second embodiment of the present invention;

FIG. 9 is a graph of axial chromatic aberration of an optical lens according to a second embodiment of the present invention;

FIG. 10 is a vertical axis chromatic aberration diagram of an optical lens according to a second embodiment of the present invention;

FIG. 11 is a schematic structural diagram of an optical lens assembly according to a third embodiment of the present invention;

FIG. 12 is a field curvature graph of an optical lens according to a third embodiment of the present invention;

fig. 13 is a distortion graph of an optical lens in a third embodiment of the present invention;

FIG. 14 is a graph illustrating axial chromatic aberration of an optical lens according to a third embodiment of the present invention;

FIG. 15 is a vertical axis chromatic aberration diagram of an optical lens according to a third embodiment of the present invention;

FIG. 16 is a schematic structural diagram of an optical lens system according to a fourth embodiment of the present invention;

fig. 17 is a field curvature graph of an optical lens in a fourth embodiment of the present invention;

fig. 18 is a distortion graph of an optical lens in a fourth embodiment of the present invention;

FIG. 19 is a graph showing axial chromatic aberration of an optical lens according to a fourth embodiment of the present invention;

FIG. 20 is a vertical axis chromatic aberration diagram of an optical lens according to a fourth embodiment of the present invention;

FIG. 21 is a schematic diagram of the edge face tilt angle of the third lens of the present invention.

Description of the symbols of the main elements:

the following specific embodiments will further illustrate the invention in conjunction with the above-described figures.

Detailed Description

To facilitate an understanding of the invention, the invention will now be described more fully with reference to the accompanying drawings. Several embodiments of the 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, this embodiment is 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. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

In order to pursue a high-definition pixel effect, the number of lenses of most mobile phone optical lenses popular in the market is correspondingly increased, and the size of the lens is larger due to the structural construction.

Accordingly, the present invention provides an optical lens, which comprises six lenses in total, in order from an object side to an image side along an optical axis:

a diaphragm;

the first lens can have positive focal power, and the object side surface of the first lens can be a convex surface, and the image side surface of the first lens can be a concave surface;

the second lens can have positive focal power or negative focal power, and the image side surface of the second lens can be a concave surface;

the third lens element may have a positive or negative optical power, and its object-side surface may be convex at the paraxial region;

the fourth lens can have positive focal power or negative focal power, the object side surface of the fourth lens can be a concave surface, and the image side surface of the fourth lens can be a convex surface;

the fifth lens element may have a positive optical power, and an object-side surface thereof may be convex at a paraxial region;

the sixth lens element can have a negative optical power, and the object side surface can be concave at the paraxial region and the image side surface can be concave at the paraxial region;

and (3) a filter.

In an exemplary embodiment, ImgH, which is half the diagonal length of an effective pixel area on an imaging surface of an optical lens, and TTL, which is the total optical length of the optical lens, satisfy the following conditional expressions: imgH/TTL is more than 0.7 and less than 0.8. When the ImgH/TTL is more than 0.7, the optical lens has relatively high image height, so that larger overall screen imaging is met; when the ImgH/TTL is less than 0.8, the total length of the optical lens is well controlled, and the miniaturization characteristic of the lens is met; when the condition formula is met in a comprehensive view, the optical total length of the optical lens can be reasonably controlled while full-screen imaging is obtained, and the characteristic of miniaturization of the lens is favorably realized.

In an exemplary embodiment, the center thickness CT3 of the third lens and the air interval T34 of the third lens and the fourth lens on the optical axis satisfy the following conditional expression: 0.3 < CT3/T34 < 1.9. By controlling the ratio of the central thickness of the third lens to the air space of the third lens and the fourth lens on the optical axis, the sensitivity of the third lens can be reduced, and the structural arrangement of the optical lens is facilitated.

In an exemplary embodiment, SAGs 41j at an object-side distance jmm from the optical axis of the fourth lens and SAGs 41i at an object-side distance imm of the fourth lens and SAGs 42j at an image-side distance jmm of the fourth lens and SAGs 42i at an image-side distance imm of the fourth lens satisfy the following conditional expressions: SAG41j-SAG41i < 0; SAG42j-SAG42i < 0; wherein j = i + 0.1. The curved surface shape of the fourth lens is reasonably limited, so that the surface shapes of the object side surface of the fourth lens and the image side surface of the fourth lens have no inflection point, and the eccentric sensitivity is prevented from being increased.

In an exemplary embodiment, the edge face inclination angle θ 31 of the object side surface of the third lens and the edge face inclination angle θ 32 of the image side surface of the third lens satisfy the following conditional expression: 1.8 < theta 32/theta 31 < 2.2. When the theta 32/theta 31 is more than 1.8, the aberration of the light entering the third lens can be well modified, and the light is transmitted to the fourth lens; when theta 32/theta 31 is less than 2.2, ghost images generated by overlarge edge inclination angles of the third lens can be avoided while satisfying Chief Ray incident angles (CRA).

In an exemplary embodiment, the effective half aperture DM11 of the object side surface of the first lens of the optical lens and the effective half aperture DM32 of the image side surface of the third lens of the optical lens satisfy the following conditional expression: DM32/DM11 is more than 0.9 and less than 1.1. When the ratio of DM32/DM11 is more than 0.9, the third lens receives the light of the front lens and transmits the light to the next lens, the aberration of the second lens can be improved, the light is transmitted to the fourth lens at a proper angle, the aberration compensation is facilitated, the area of an imaging surface is increased, but if the ratio of DM32/DM11 is too large, the size and the volume of the lens head are large, and the miniaturization trend is not met; when DM32/DM11 is less than 1.1, the aperture of the optical lens can be reasonably controlled, so that the size of the head of the lens is smaller, the miniaturization characteristic of the head of the lens is ensured, and the full-screen high-definition pixel imaging and the miniaturization compatibility of the head of the lens are favorably realized.

In an exemplary embodiment, the effective aperture diameter D of the optical lens and the effective focal length f of the optical lens satisfy the following conditional expression: f/D is more than 5.0 and less than 5.5. Sufficient light flux can be maintained through the clear aperture of reasonable control camera lens, and in the process of increasing the light flux, the system has the advantage of large aperture, thereby reducing the aberration of the marginal field of view and simultaneously enhancing the imaging effect in dark environment, so that the system can also obtain brighter and clear imaging in the environment with insufficient light, and the requirement of shooting by a user in the dark environment is met.

In an exemplary embodiment, the focal length f1 of the first lens and the focal length f3 of the third lens satisfy the following conditional expression: -0.04 < f1/f3 < 0.17. The method ensures that the correction difficulty of the curvature of field is reduced while avoiding the increase of the focal power and the eccentricity sensitivity of the first lens.

In an exemplary embodiment, the focal length f1 of the first lens, the focal length f3 of the third lens, and the effective focal length f of the optical lens satisfy the following conditional expression: 1.2 < (1/f1-1/f3)/(1/f) < 1.6. The eccentric sensitivity of the first lens is shared by the third lens, the aperture of the third lens is relatively small, the eccentric sensitivity cannot be large, the difficulty of production and processing can be greatly reduced by balancing the eccentric sensitivity of the first lens and the third lens, and the production yield of the lens is effectively improved while high imaging quality is ensured.

In an exemplary embodiment, the aperture diameter DT of the optical lens and the object-side clear aperture diameter D31 of the third lens satisfy the following conditional expression: 1.1 < DT/D31 < 1.3. By controlling the aperture of the third lens in the lens, when DT/D31 is larger than 1.1, the field angle of the optical lens is larger, and the shooting scene is wider; when DT/D31 is less than 1.3, the difficulty of aberration correction is reduced.

In an exemplary embodiment, the diaphragm aperture DT of the optical lens and the half ImgH of the diagonal length of the effective pixel area on the imaging plane of the optical lens satisfy the following conditional expression: 0.58 < DT/ImgH < 0.61. When DT/ImgH is more than 0.58, the light flux of the optical lens can be effectively ensured, and enough illumination intensity is ensured; when DT/ImgH is less than 0.61, the optical lens with high pixels and high imaging quality can be obtained, and the high requirements of modern people on shooting are met.

In an exemplary embodiment, the radius of curvature R32 of the image-side surface of the third lens, the radius of curvature R11 of the object-side surface of the first lens, and the diaphragm aperture DT of the optical lens satisfy the following conditional expressions: 1.1 < (1/R11-1/R32). times.DT < 1.6. When (1/R11-1/R32) multiplied by DT is less than 1.6, the aberration of the lens head can be well modified, and the high-definition pixel characteristics are met; when the light ray is 1.1 < (1/R11-1/R32) multiplied by DT, the light ray can be ensured to transmit through the lens smoothly, the risk of generating ghost images is reduced, and the miniaturization characteristic of the lens is met.

In an exemplary embodiment, the central thickness CT4 of the fourth lens and the central thickness CT5 of the fifth lens satisfy the following conditional expression: 0.8 < CT4/CT5 < 2.4. By controlling the ratio of the central thicknesses of the fourth lens and the fifth lens, the total length of the optical system is favorably compressed, and the ultrathin effect is realized.

In an exemplary embodiment, the central thickness CT4 of the fourth lens and the air interval T34 of the third lens from the fourth lens on the optical axis satisfy the following conditional expressions: 0.5 < CT4/T34 < 5.6. The ratio of the central thickness of the fourth lens to the air space of the third lens and the fourth lens on the optical axis is controlled, so that the space occupation ratio of the fourth lens is reduced, the lens assembly process is guaranteed, the miniaturization of the optical lens is realized, and the requirement of the whole machine is met more easily.

In an exemplary embodiment, the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens may be aspheric lenses, and plastic aspheric lenses are used for the lenses. The aspheric lens can effectively reduce the number of the lenses, correct aberration and provide better optical performance.

In an exemplary embodiment, as a manner, when each lens in the optical lens is an aspherical lens, each aspherical surface type of the optical lens may satisfy the following equation:

，

where z is a distance rise from the aspheric vertex at a position having a height h in the optical axis direction, c is a paraxial radius of curvature of the surface, k is a conic coefficient conic, and A2i is an aspheric surface type coefficient of order 2 i.

The optical lens provided in the exemplary embodiment reasonably matches the lens shape and focal power combination among the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens through the six lenses with specific focal powers, so that the structure is more compact on the premise of high pixel and clear imaging of the lens is met, the miniaturization of the lens and the balance of high pixel are better realized, and the user shooting experience is improved.

In an exemplary embodiment, FIG. 21 shows a schematic diagram of the face tilt angle of the edge of the third lens of the present invention.

The invention is further illustrated by the following examples. In each of the following embodiments, the thickness, the curvature radius, and the material of each lens of the optical lens are different, and specific differences can be referred to in the parameter tables of the embodiments.

First embodiment

Referring to fig. 1, a schematic structural diagram of an optical lens according to a first embodiment of the present invention is shown, the optical lens sequentially includes, from an object side to an image side along a paraxial region: the stop ST, 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 filter G1.

The first lens element L1 is a plastic aspheric lens with positive power, the object-side surface S1 is convex, and the image-side surface S2 is concave;

the second lens element L2 is a plastic aspheric lens with negative power, the object-side surface S3 is concave at paraxial region and has a point of inflection, and the image-side surface S4 is concave;

the third lens element L3 is a plastic aspheric lens with positive power, the object-side surface S5 is convex at paraxial region and has a point of inflection, and the image-side surface S6 is convex;

the fourth lens element L4 is a plastic aspheric lens with negative power, the object-side surface S7 is concave, and the image-side surface S8 is convex;

the fifth lens element L5 is a plastic aspheric lens with positive power, the object-side surface S9 is convex at paraxial region, and the image-side surface S10 is convex at paraxial region and has a inflection point;

the sixth lens element L6 is a plastic aspheric lens with negative power, the object side S11 is concave at the paraxial region and has a inflection point, and the image side S12 is concave at the paraxial region and has a inflection point.

The design parameters of the optical lens provided in this embodiment are shown in table 1, where R represents the radius of curvature, d represents the optical surface distance, and n_dD-line refractive index, V, of the material_dRepresents the abbe number of the material.

TABLE 1

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

TABLE 2

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

The field curvature curve of fig. 2 indicates the degree of curvature of the meridional image plane and the sagittal image plane, the horizontal axis indicates the offset amount (unit: mm), and the vertical axis indicates the half field angle (unit: °). As can be seen from fig. 2, the field curvature of the meridional image plane and the sagittal image plane is controlled within ± 0.2mm, which indicates that the field curvature of the optical lens is better corrected.

The distortion curve in fig. 3 shows f-tan θ distortion at different image heights on the image forming plane, the abscissa shows f-tan θ distortion (unit:%), and the ordinate shows half field angle (unit:%). As can be seen from fig. 3, the optical distortion at different image heights on the image plane is controlled within ± 2%, which indicates that the distortion of the optical lens is well corrected.

The axial chromatic aberration curve of fig. 4 represents the aberration on the optical axis at the imaging plane, the horizontal axis represents the axial chromatic aberration value (unit: mm), and the vertical axis represents the normalized pupil radius. As can be seen from fig. 4, the offset of the axial chromatic aberration is controlled within ± 0.04mm, which indicates that the optical lens can effectively correct the axial chromatic aberration.

The vertical axis chromatic aberration in fig. 5 indicates a chromatic aberration at different image heights on the image forming plane for each wavelength with respect to the center wavelength (0.55 μm), the horizontal axis indicates a vertical axis chromatic aberration value (unit: μm) for each wavelength with respect to the center wavelength, and the vertical axis indicates a normalized angle of view. As can be seen from FIG. 5, the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength are controlled within + -1 μm, which shows that the optical lens can effectively correct the aberration of the fringe field and the secondary spectrum of the whole image plane.

Second embodiment

Referring to fig. 6, a schematic structural diagram of an optical lens according to a second embodiment of the present invention is shown, the optical lens sequentially includes, from an object side to an image side along a paraxial region: the stop ST, 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 filter G1.

the third lens element L3 is a plastic aspheric lens with positive power, the object side S5 is convex at paraxial region and has a inflection point, and the image side S6 is concave at paraxial region and has a inflection point;

the fifth lens element L5 is a plastic aspheric lens with positive power, the object-side surface S9 is convex at paraxial region and the image-side surface S10 is convex;

The true bookRelevant parameters of each lens in the optical lens provided in the embodiment are shown in table 3, wherein R represents a curvature radius, d represents an optical surface pitch, and n_dD-line refractive index, V, of the material_dRepresents the abbe number of the material.

TABLE 3

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

TABLE 4

In the present embodiment, graphs of curvature of field, distortion, axial chromatic aberration, and vertical axis chromatic aberration of the optical lens are shown in fig. 7, 8, 9, and 10, respectively.

The field curvature curve of fig. 7 indicates the degree of curvature of the meridional image plane and the sagittal image plane, the horizontal axis indicates the offset amount (unit: mm), and the vertical axis indicates the half field angle (unit: °). As can be seen from fig. 7, the field curvature of the meridional image plane and the sagittal image plane is controlled within ± 0.04mm, which indicates that the field curvature of the optical lens is better corrected.

The distortion curve in fig. 8 shows f-tan θ distortion at different image heights on the image forming plane, the abscissa shows f-tan θ distortion (unit:%), and the ordinate shows half field angle (unit:%). As can be seen from fig. 8, the optical distortion at different image heights on the image plane is controlled within ± 1.2%, which indicates that the distortion of the optical lens is well corrected.

The axial chromatic aberration curve of fig. 9 represents aberration on the optical axis at the imaging plane, the horizontal axis represents the axial chromatic aberration value (unit: mm), and the vertical axis represents the normalized pupil radius. As can be seen from fig. 9, the offset of the axial chromatic aberration is controlled within ± 0.03mm, which indicates that the optical lens can effectively correct the axial chromatic aberration.

In fig. 10, the vertical axis chromatic aberration represents the chromatic aberration at different image heights on the image forming plane for each wavelength with respect to the center wavelength (0.55 μm), the horizontal axis represents the vertical axis chromatic aberration value (unit: μm) for each wavelength with respect to the center wavelength, and the vertical axis represents the normalized angle of view. As can be seen from fig. 10, the vertical chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ± 1 μm, which indicates that the optical lens can effectively correct the aberration of the fringe field and the secondary spectrum of the entire image plane.

Third embodiment

Referring to fig. 11, a schematic structural diagram of an optical lens according to a third embodiment of the present invention is shown, the optical lens sequentially includes, from an object side to an image side along a paraxial region: the stop ST, 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 filter G1.

the second lens element L2 is a plastic aspheric lens with positive refractive power, the object-side surface S3 is convex, and the image-side surface S4 is concave;

the fifth lens element L5 is a plastic aspheric lens with positive power, the object-side surface S9 is convex at the paraxial region, and the image-side surface S10 is concave at the paraxial region and has a inflection point;

The design parameters of the optical lens provided in this embodiment are shown in table 5, where R represents the radius of curvature, d represents the optical surface distance, and n_dD-line refractive index, V, of the material_dRepresents the abbe number of the material.

TABLE 5

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

TABLE 6

In the present embodiment, graphs of curvature of field, distortion, axial chromatic aberration, and vertical axis chromatic aberration of the optical lens are shown in fig. 12, 13, 14, and 15, respectively.

The field curvature curve in fig. 12 indicates the degree of curvature of the meridional image plane and the sagittal image plane, the horizontal axis indicates the offset amount (unit: mm), and the vertical axis indicates the half field angle (unit: °). As can be seen from fig. 12, the field curvature of the meridional image plane and the sagittal image plane is controlled within ± 0.12mm, which indicates that the field curvature of the optical lens is better corrected;

the distortion curve in fig. 13 shows f-tan θ distortion at different image heights on the image forming plane, the abscissa shows f-tan θ distortion (unit:%), and the ordinate shows half field angle (unit:%). As can be seen from fig. 13, the optical distortion at different image heights on the image plane is controlled within ± 2%, which indicates that the distortion of the optical lens is well corrected;

the axial chromatic aberration curve of fig. 14 represents the aberration on the optical axis at the imaging plane, the horizontal axis represents the axial chromatic aberration value (unit: mm), and the vertical axis represents the normalized pupil radius. As can be seen from fig. 14, the offset of the axial chromatic aberration is controlled within ± 0.03mm, which indicates that the optical lens can effectively correct the axial chromatic aberration;

in fig. 15, the vertical axis chromatic aberration represents the chromatic aberration at different image heights on the image forming plane for each wavelength with respect to the center wavelength (0.55 μm), the horizontal axis represents the vertical axis chromatic aberration value (unit: μm) for each wavelength with respect to the center wavelength, and the vertical axis represents the normalized angle of view. As can be seen from fig. 15, the vertical chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ± 4 μm, which indicates that the optical lens can effectively correct the aberration of the fringe field and the secondary spectrum of the entire image plane.

Fourth embodiment

Referring to fig. 16, a schematic structural diagram of an optical lens according to a third embodiment of the present invention is shown, the optical lens sequentially includes, from an object side to an image side along a paraxial region: the stop ST, 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 filter G1.

the second lens element L2 is a plastic aspheric lens with positive power, the object-side surface S3 is concave at paraxial region and has a point of inflection, and the image-side surface S4 is concave;

the third lens element L3 is a plastic aspheric lens with negative power, the object-side surface S5 is convex at paraxial region and has a inflection point, and the image-side surface S6 is concave at paraxial region and has an inflection point;

the fourth lens element L4 is a plastic aspheric lens with positive power, the object-side surface S7 is concave, and the image-side surface S8 is convex;

The relevant parameters of each lens in the optical lens in this embodiment are shown in table 7, where R represents the radius of curvature, d represents the optical surface distance, and n_dD-line refractive index, V, of the material_dRepresents the abbe number of the material.

TABLE 7

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

TABLE 8

In the present embodiment, graphs of curvature of field, distortion, axial chromatic aberration, and vertical axis chromatic aberration of the optical lens are shown in fig. 17, 18, 19, and 20, respectively.

The field curvature curve in fig. 17 indicates the degree of curvature of the meridional image plane and the sagittal image plane, the horizontal axis indicates the offset amount (unit: mm), and the vertical axis indicates the half field angle (unit: °). As can be seen from fig. 17, the field curvature of the meridional image plane and the sagittal image plane is controlled within ± 0.12mm, which indicates that the field curvature of the optical lens is better corrected;

the distortion curve in fig. 18 shows f-tan θ distortion at different image heights on the image forming plane, the abscissa shows f-tan θ distortion (unit:%), and the ordinate shows half field angle (unit:%). As can be seen from fig. 18, the optical distortion at different image heights on the image plane is controlled within ± 2%, which indicates that the distortion of the optical lens is well corrected;

the axial chromatic aberration curve of fig. 19 represents the aberration on the optical axis at the imaging plane, the horizontal axis represents the axial chromatic aberration value (unit: mm), and the vertical axis represents the normalized pupil radius. As can be seen from fig. 19, the offset of the axial chromatic aberration is controlled within ± 0.04mm, which indicates that the optical lens can effectively correct the axial chromatic aberration;

in fig. 20, the vertical axis chromatic aberration represents the chromatic aberration at different image heights on the image forming plane for each wavelength with respect to the center wavelength (0.55 μm), the horizontal axis represents the vertical axis chromatic aberration value (unit: μm) for each wavelength with respect to the center wavelength, and the vertical axis represents the normalized angle of view. As can be seen from fig. 20, the vertical chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ± 3 μm, which indicates that the optical lens can effectively correct the aberration of the fringe field and the secondary spectrum of the entire image plane.

Table 9 shows the optical characteristics corresponding to the above four embodiments, which mainly include the effective focal length F, F #, total optical length TTL, and field of view FOV of the optical lens, and the values corresponding to each conditional expression.

TABLE 9

In summary, the optical lens provided in this embodiment has at least the following advantages:

(1) the aperture of the designed third lens is relatively small, and the diaphragm and the shapes of other lenses are reasonably arranged, so that the optical lens has a smaller windowing aperture, and a relatively larger screen occupation ratio is obtained.

(2) Six plastic aspheric lenses with specific focal power and specific surface types are adopted for matching, the imaging quality of the ultra-high definition pixels is obtained, meanwhile, the miniaturization characteristic of the lens is guaranteed, and the development trend of the lens can be well met.

(3) Compared with a high-definition pixel lens with high price, the invention also provides a mature manufacturing process on the premise of ensuring high pixel and small volume, greatly reduces the manufacturing cost and is more beneficial to market popularization.

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 present 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 lens system comprising six lenses, in order from an object side to an image side along an optical axis:

a diaphragm;

2. The optical lens of claim 1, wherein SAGs 41j at an object-side distance of j mm from an optical axis of the fourth lens and 41i at an object-side distance of i mm from an optical axis of the fourth lens and SAGs 42j at an image-side distance of j mm from an optical axis of the fourth lens and SAG42i at an image-side distance of imm from an optical axis of the fourth lens satisfy: SAG41j-SAG41i < 0, SAG42j-SAG42i < 0, j = i + 0.1.

3. An optical lens according to claim 1, wherein the edge face inclination angle θ 32 of the image side face of the third lens and the edge face inclination angle θ 31 of the object side face of the third lens satisfy: 1.8 < theta 32/theta 31 < 2.2.

4. An optical lens according to claim 1, characterized in that the effective half aperture DM11 of the object side surface of the first lens and the effective half aperture DM32 of the image side surface of the third lens satisfy: DM32/DM11 is more than 0.9 and less than 1.1.

5. An optical lens according to claim 1, wherein the focal length f1 of the first lens and the focal length f3 of the third lens satisfy: -0.04 < f1/f3 < 0.17.

6. An optical lens according to claim 1, wherein the focal length f1 of the first lens, the focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: 1.2 < (1/f1-1/f3)/(1/f) < 1.6.

7. An optical lens according to claim 1, wherein the effective aperture diameter D of the optical lens and the effective focal length f of the optical lens satisfy the following conditional expression: f/D is more than 5.0 and less than 5.5.

8. An optical lens according to claim 1, wherein a radius of curvature R32 of an image-side surface of the third lens, a radius of curvature R11 of an object-side surface of the first lens, and a stop aperture DT of the optical lens satisfy: 1.1 < (1/R11-1/R32). times.DT < 1.6.

9. An optical lens according to claim 1, wherein the central thickness CT4 of the fourth lens and the central thickness CT5 of the fifth lens satisfy the following conditional expression: 0.8 < CT4/CT5 < 2.4.

10. An optical lens according to claim 1, wherein the central thickness CT4 of the fourth lens and the air interval T34 of the third lens from the fourth lens on the optical axis satisfy the following conditional expressions: 0.5 < CT4/T34 < 5.6.