CN114815172B

CN114815172B - Optical lens

Info

Publication number: CN114815172B
Application number: CN202210738045.3A
Authority: CN
Inventors: 章彬炜; 徐丽丽; 曾昊杰
Original assignee: Jiangxi Lianyi Optics Co Ltd
Current assignee: Jiangxi Lianyi Optics Co Ltd
Priority date: 2022-06-28
Filing date: 2022-06-28
Publication date: 2022-11-01
Anticipated expiration: 2042-06-28
Also published as: CN114815172A

Abstract

The invention discloses an optical lens, which comprises the following components in sequence from an object side to an imaging surface along an optical axis: a first lens having a positive optical power, an object side surface of the first lens being convex at a paraxial region; a diaphragm; a second lens having a positive optical power, an object-side surface of the second lens being convex at a paraxial region, an image-side surface of the second lens being convex; the third lens is provided with negative focal power, the object side surface of the third lens is a concave surface, and the image side surface of the third lens is a convex surface; a fourth lens having a positive optical power, the fourth lens having both an object-side surface and an image-side surface that are convex at a paraxial region; a fifth lens having a negative optical power, an object-side surface of the fifth lens being convex at a paraxial region and an image-side surface of the fifth lens being concave at a paraxial region; the optical lens at least comprises an aspheric lens. The optical lens has the advantages of high pixel, large wide angle, short total length and miniaturized head.

Description

Optical lens

Technical Field

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

Background

With the rapid growth of consumer electronics market and the popularity of social, video and live broadcast software, people have higher and higher requirements for the imaging quality of the camera lens, and the camera lens even becomes an index which is considered primarily when a consumer purchases electronic equipment.

Along with the continuous development of mobile information technology, portable electronic equipment such as smart phones is also developing towards the directions of lightness and thinness, full-screen, ultra-high definition imaging and the like, from the rise of full-screen such as 'bang' screen, 'water drop' screen and the like, the requirements of the mobile phone industry on the screen occupation ratio are higher and higher, and a camera is used as a vital component of the mobile phone and needs to reduce the size of the head of the camera to increase the screen occupation ratio. Meanwhile, in order to provide a high-quality photographing function for a user in an all-round manner, a mainstream configuration currently carried on a portable electronic device is a combination of a large image plane lens, a telephoto lens and a wide-angle lens, wherein the wide-angle lens has the characteristics of a large field angle and a long depth of field, so that a long-range feeling is easily provided for a photographer, and the image-taking device is beneficial to enhancing the image infectivity and enabling the photographer to have a feeling of being personally on the scene. In order to seek better imaging effect, an increasing demand is placed on an imaging lens mounted on a portable electronic apparatus. However, the existing camera lens has a large head size, so that the screen occupation ratio is difficult to increase, and the field angle of the camera lens is often small, so that a picture in a large field range is difficult to shoot, and better visual experience cannot be brought to consumers.

Disclosure of Invention

Therefore, an object of the present invention is to provide an optical lens having advantages of high pixel, large wide angle, short overall length, and small head size, and capable of meeting the usage requirements of portable electronic devices.

The embodiment of the invention implements the above object by the following technical scheme.

The invention provides an optical lens, which sequentially comprises the following components from an object side to an imaging surface along an optical axis: a first lens having a positive optical power, an object side surface of the first lens being convex at a paraxial region; a diaphragm; a second lens having a positive optical power, an object-side surface of the second lens being convex at a paraxial region, an image-side surface of the second lens being convex; the third lens is provided with negative focal power, the object side surface of the third lens is a concave surface, and the image side surface of the third lens is a convex surface; a fourth lens having positive optical power, the fourth lens having both an object-side surface and an image-side surface that are convex at a paraxial region; a fifth lens having a negative optical power, an object-side surface of the fifth lens being convex at a paraxial region, an image-side surface of the fifth lens being concave at a paraxial region; the optical lens at least comprises an aspheric lens.

Compared with the prior art, the optical lens provided by the invention adopts five aspheric lenses with specific focal power, and has the advantages of good imaging quality, super wide angle, total length and head miniaturization through specific surface shape collocation and reasonable focal power distribution; meanwhile, the distance between the lenses is reasonably configured, so that the depth of the small head can be deeper, and the requirements of current ultrathin and ultrahigh screen occupation ratios are better met.

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 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 vertical axis chromatic aberration diagram of an optical lens according to a first embodiment of the present invention;

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

FIG. 5 is a field curvature graph of an optical lens according to a second embodiment of the present invention;

FIG. 6 is a vertical axis chromatic aberration diagram of an optical lens according to a second embodiment of the present invention;

FIG. 7 is a schematic structural diagram of an optical lens system according to a third embodiment of the present invention;

FIG. 8 is a field curvature diagram of an optical lens according to a third embodiment of the present invention;

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

Detailed Description

In order to make the objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. 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, 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.

The present invention provides an optical lens, sequentially including, from an object side to an image plane along an optical axis: the lens comprises a first lens, a diaphragm, a second lens, a third lens, a fourth lens, a fifth lens and an optical filter.

Wherein the first lens has a positive focal power, and the object-side surface of the first lens is convex at the paraxial region;

the second lens has positive focal power, the object side surface of the second lens is convex at a paraxial region, and the image side surface of the second lens is convex;

the third lens has negative focal power, the object side surface of the third lens is a concave surface, and the image side surface of the third lens is a convex surface;

the fourth lens has positive focal power, and both the object-side surface and the image-side surface of the fourth lens are convex at a paraxial region;

the fifth lens element has a negative optical power, the fifth lens element has a convex object-side surface at a paraxial region and a concave image-side surface at a paraxial region;

the first lens to the fifth lens at least comprise an aspheric lens.

The optical lens adopts a combination of a plurality of aspheric lenses, and the diaphragm is arranged between the first lens and the second lens, so that light rays entering the optical system can be effectively converged, the aperture of the optical system is reduced, the field angle of the lens is improved, and the incidence angle of the chief rays of the corresponding chip is better matched; meanwhile, the optical lens has good imaging quality through specific surface shape collocation and reasonable focal power distribution.

In some embodiments, the optical lens satisfies the following conditional expression:

1.5<f1/f2<5.5；（1）

0.8<f2/f<2.0；（2）

wherein f1 denotes a focal length of the first lens, f2 denotes a focal length of the second lens, and f denotes an effective focal length of the optical lens. Satisfy above-mentioned conditional expression (1) and (2), through the focus relation of rationally setting up first, two lenses around the diaphragm, be favorable to the distortion of better control camera lens, improve whole imaging quality when realizing the big wide angle of camera lens.

1.5<TTL/f<2.0；（3）

0.6<f/IH<0.7；（4）

wherein, TTL represents the total optical length of the optical lens, f represents the effective focal length of the optical lens, and IH represents the image height corresponding to the half field angle of the optical lens. The optical lens meets the condition formula (3), and has smaller total length on the basis of large image height by reasonably setting the value of TTL/f, so that the miniaturization of the lens is maintained. Satisfying the above conditional expression (4), the optical system can obtain a larger angle of view, and the balance between the large image plane and the wide angle of view of the lens can be better realized.

0.1<CT2/TTL<0.14；（5）

1.1<CT2/CT3<2.5；（6）

wherein, TTL represents an optical total length of the optical lens, CT2 represents a center thickness of the second lens, and CT3 represents a center thickness of the third lens. The central thickness of the second lens is thicker and the central thickness of the third lens is thinner by reasonably controlling the central thicknesses of the second lens and the third lens when the conditional expressions (5) and (6) are met, so that the depth of the small head can be deeper, and the ultrathin lens is better realized.

0.9<TTL/(f×tanθ)<1.1；（7）

wherein, TTL represents an optical total length of the optical lens, f represents an effective focal length of the optical lens, and θ represents a half field angle of the optical lens. Satisfying the conditional expression (7) can better realize the miniaturization of the lens and the balance of a large image plane.

0.8<IH/(f×tanθ)<0.9；（8）

where θ represents a half field angle of the optical lens, IH represents an image height corresponding to the half field angle of the optical lens, and f represents an effective focal length of the optical lens. The distortion of the optical lens can be well corrected by satisfying the conditional expression (8), the reduction degree of the shot image is extremely high, and the integral imaging quality is improved.

-2.0<f3/f<-0.5；（9）

-5<(R31+R32)/(R31-R32)<-2；（10）

where f3 denotes a focal length of the third lens, f denotes an effective focal length of the optical lens, R31 denotes a radius of curvature of an object-side surface of the third lens, and R32 denotes a radius of curvature of an image-side surface of the third lens. The third lens can better correct system aberration by reasonably distributing the focal length and the surface type of the third lens and the imaging quality of the optical lens is improved by meeting the conditional expressions (9) and (10).

0.3<R41/f<1；（11）

0.16<CT4/TTL<0.22；（12）

wherein f represents an effective focal length of the optical lens, R41 represents a curvature radius of an object side surface of the fourth lens, CT4 represents a center thickness of the fourth lens, and TTL represents an optical total length of the optical lens. The conditional expressions (11) and (12) are satisfied, the shape of the fourth lens is reasonably controlled, and the thickness of the fourth lens is in a reasonable range, so that the formability of the lens is favorably improved, and the manufacturing yield is improved.

0.05<CT_1st/TTL<0.1；（13）

wherein, CT_1stAnd the distance between the object side surface of the first lens and the diaphragm on the optical axis is represented, and TTL represents the total optical length of the optical lens. When the above conditional expression (13) is satisfied,the diaphragm is arranged between the first lens and the second lens, and the position of the diaphragm is adjusted, so that the optical lens can obtain a wider field angle, aberration can be balanced better, and the imaging quality of the lens is improved.

-0.5<R22/R21<0；（14）

wherein R21 denotes a radius of curvature of an object-side surface of the second lens, and R22 denotes a radius of curvature of an image-side surface of the second lens. The second lens sets up behind the diaphragm, has important influence to the turn of control light, satisfies above-mentioned conditional expression (14), through the face type that rationally sets up the positive lens of second, can effectively slow down the turn of light, can better correct the distortion of system when realizing super large wide angle, improves marginal imaging quality.

115°<FOV<135°；（15）

TTL<3.8mm；（16）

wherein, FOV represents the maximum field angle of the optical lens, TTL represents the optical total length of the optical lens. Satisfying the above conditional expressions (15) and (16), the wide viewing angle and miniaturization of the lens can be better realized, and the use requirement of the portable electronic device is satisfied.

0.08<(SD31-SD11)/(SD31+SD11)<0.15；（17）

wherein SD31 denotes an effective aperture of the object side surface of the third lens, and SD11 denotes an effective aperture of the object side surface of the first lens. Satisfying conditional expression (17), can making the lens bore of first lens to third lens maintain a less size, be favorable to the lens structural design, realize that the camera lens head is done smallly to satisfy the demand that super high screen accounts for the ratio.

0.6<f/ΣCT<0.8；（18）

wherein f represents an effective focal length of the optical lens, and Σ CT represents a sum of central thicknesses of the first lens to the fifth lens. Satisfying the above conditional expression (18), the total thickness of the center of each lens element is reasonably distributed, so as to improve the yield, shorten the total length of the optical imaging system, and maintain the miniaturization for better application in portable electronic products.

0.02<CT34/(SD41-SD31)<0.07；（19）

wherein CT34 denotes an air gap on the optical axis between the third lens and the fourth lens, SD31 denotes an effective aperture of an object-side surface of the third lens, and SD41 denotes an effective aperture of an object-side surface of the fourth lens. Satisfying the above conditional expression (19), by reasonably distributing the air gap distance between the rims of the third and fourth lenses and controlling the effective apertures of the third and fourth lenses, the optical lens can obtain a smaller head size, and at the same time, it is helpful to reduce the total length of the system, and can keep the system compact.

-0.5<f3/f1<-0.1；（20）

where f1 denotes a focal length of the first lens, and f3 denotes a focal length of the third lens. Satisfy above-mentioned conditional expression (20), through the focus of rational distribution first lens and third lens, effectively reduce optical system's sensitivity, the out-of-focus curve dispersion of each visual field of control that simultaneously can be fine improves the image quality of camera lens.

In some embodiments, the image-side surface of the first lens element in the optical lens assembly is convex at the paraxial region, and in other embodiments, the image-side surface of the first lens element is concave at the paraxial region, and the first lens element adopts different combinations of surface types, which can achieve good imaging effect.

In the application, in order to better reduce the volume of the lens and reduce the cost, the optical lens at least has the advantages of good imaging quality, super wide angle, low sensitivity, total length and head miniaturization by adopting the combination of five plastic lenses and reasonably distributing the focal power of each lens and optimizing the shape of an aspheric surface. Specifically, the first lens element to the fifth lens element can all adopt plastic aspheric lenses, and the aspheric lenses can effectively correct aberration, improve imaging quality and provide optical performance products with higher cost performance.

The invention is further illustrated below in the following examples. In various embodiments, the thickness, the curvature radius, and the material selection part of each lens in the optical lens are different, and specific differences can be referred to the parameter tables of the various embodiments. The following examples are only preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the following examples, and any other changes, substitutions, combinations or simplifications which do not depart from the gist of the present invention should be construed as being equivalent replacements within the scope of the present invention.

In each embodiment of the present invention, when the lens is an aspherical lens, the surface shape of the aspherical lens satisfies the following equation:

wherein z is the distance rise from the aspheric surface vertex when the aspheric surface is at the position of height h along the optical axis direction, c is the paraxial curvature of the surface, k is conic coefficient, A_2iIs the aspheric surface type coefficient of 2i 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 image plane S13 along an optical axis: the lens includes a first lens L1, an aperture stop ST, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, and a filter G1.

The first lens L1 has positive focal power, the object-side surface S1 of the first lens is convex at a paraxial region, and the image-side surface S2 of the first lens is convex;

the second lens L2 has positive focal power, the object-side surface S3 of the second lens is convex at the paraxial region, and the image-side surface S4 of the second lens is convex;

the third lens L3 has negative focal power, the object side surface S5 of the third lens is a concave surface, and the image side surface S6 of the third lens is a convex surface;

the fourth lens L4 has positive optical power, and both the object-side surface S7 and the image-side surface S8 of the fourth lens are convex at the paraxial region;

the fifth lens element L5 has negative optical power, and the object-side surface S9 of the fifth lens element is convex at the paraxial region and the image-side surface S10 of the fifth lens element is concave at the paraxial region;

the object side surface of the filter G1 is S11, and the image side surface is S12.

The first lens element L1, the second lens element L2, the third lens element L3, the fourth lens element L4 and the fifth lens element L5 are all plastic aspheric lens elements.

Specifically, the present embodiment provides optical lens 100 having the design parameters of each lens as shown in table 1.

TABLE 1

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

TABLE 2

Referring to fig. 2 and fig. 3, a field curvature graph and a vertical axis chromatic aberration graph of the optical lens 100 are respectively shown. It can be seen from fig. 2 that the curvature of field is controlled within ± 0.1mm, which indicates that the curvature of field of the optical lens 100 is better corrected; it can be seen from fig. 3 that the vertical axis chromatic aberration at different wavelengths is controlled within ± 2 microns, which indicates that the vertical axis chromatic aberration of the optical lens 100 is well corrected; as can be seen from fig. 2 and 3, the aberrations of the optical lens 100 are well balanced, and the imaging quality is good.

Second embodiment

Referring to fig. 4, a schematic structural diagram of an optical lens assembly 200 according to a second embodiment of the present invention is shown, the optical lens assembly 200 of this embodiment is substantially the same as the first embodiment, except that an image-side surface S2 of the first lens element is concave at a paraxial region, and curvature radii, aspheric coefficients, thicknesses, and materials of the lens surface types are different.

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

TABLE 3

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

TABLE 4

Referring to fig. 5 and fig. 6, a field curvature curve graph and a vertical axis chromatic aberration graph of the optical lens 200 are shown, respectively, and it can be seen from fig. 5 that the field curvature is controlled within ± 0.15mm, which indicates that the field curvature of the optical lens 200 is better corrected; it can be seen from fig. 6 that the vertical axis chromatic aberration at different wavelengths is controlled within ± 2 microns, which indicates that the vertical axis chromatic aberration of the optical lens 200 is well corrected; it can be seen from fig. 5 and 6 that the aberrations of the optical lens 200 are well balanced, and the imaging quality is good.

Third embodiment

As shown in fig. 7, which is a schematic structural diagram of an optical lens 300 according to the present embodiment, the optical lens 300 according to the present embodiment is substantially the same as the first embodiment, except that the curvature radius, aspheric coefficient, thickness and material of each lens surface type are different.

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

TABLE 5

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

TABLE 6

Referring to fig. 8 and 9, a field curvature curve graph and a vertical axis chromatic aberration graph of the optical lens 300 are shown, respectively, and it can be seen from fig. 8 that the paraxial field curvature is controlled within ± 0.1mm, which indicates that the field curvature of the optical lens 300 is better corrected; it can be seen from fig. 9 that the vertical axis chromatic aberration at different wavelengths is controlled within ± 2 microns, which indicates that the vertical axis chromatic aberration of the optical lens 300 is well corrected; it can be seen from fig. 8 and 9 that the aberrations of the optical lens 300 are well balanced, and the imaging quality is good.

Please refer to table 7, which shows the optical characteristics corresponding to the optical lens provided in the above three embodiments, including the maximum field angle FOV, the total optical length TTL, the image height IH corresponding to the half field angle, the effective focal length f, and the related values corresponding to each of the aforementioned conditional expressions.

TABLE 7

It can be seen from the field curvature graphs and the vertical axis chromatic aberration graphs of the above embodiments that the field curvature value of the optical lens in each embodiment is within ± 0.15mm, and the vertical axis chromatic aberration is within ± 2 microns, which indicates that the optical lens provided by the invention has the advantages of high pixel, super wide angle, total length, small head and good resolution.

In summary, the optical lens provided by the invention adopts five aspheric lenses with specific focal power, and has the advantages of good imaging quality, super wide angle and head miniaturization through specific surface shape collocation and reasonable focal power distribution; meanwhile, the distance between the lenses is reasonably configured, so that the depth of the small head can be deeper, and the requirement of the current ultrahigh screen ratio is better met.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean 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 invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. 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-mentioned embodiments only express several embodiments of the present invention, and the description thereof is specific and detailed, but not to be construed as limiting the scope of the present invention. It should be noted that various changes and modifications can be made by those skilled in the art without departing from the spirit of the invention, and these changes and modifications are all within the scope of the invention. Therefore, the protection scope of the present invention should be subject to the appended claims.

Claims

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

a first lens having a positive optical power, an object side surface of the first lens being convex at a paraxial region;

a diaphragm;

a second lens having a positive optical power, an object-side surface of the second lens being convex at a paraxial region, an image-side surface of the second lens being convex;

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

a fourth lens having a positive optical power, the fourth lens having both an object-side surface and an image-side surface that are convex at a paraxial region;

a fifth lens having a negative optical power, an object-side surface of the fifth lens being convex at a paraxial region and an image-side surface of the fifth lens being concave at a paraxial region;

wherein, the optical lens at least comprises an aspheric lens;

the optical lens satisfies the following conditional expression:

1.5<TTL/f<2.0；

wherein, TTL represents the optical total length of the optical lens, and f represents the effective focal length of the optical lens.

2. An optical lens according to claim 1, characterized in that the optical lens satisfies the following conditional expression:

1.5<f1/f2<5.5；

0.8<f2/f<2.0；

wherein f1 denotes a focal length of the first lens, f2 denotes a focal length of the second lens, and f denotes an effective focal length of the optical lens.

3. An optical lens according to claim 1, characterized in that the optical lens satisfies the following conditional expression:

0.6<f/IH<0.7；

where IH denotes an image height corresponding to a half field angle of the optical lens.

4. An optical lens according to claim 1, characterized in that the optical lens satisfies the following conditional expression:

0.1<CT2/TTL<0.14；

1.1<CT2/CT3<2.5；

wherein, TTL represents an optical total length of the optical lens, CT2 represents a center thickness of the second lens, and CT3 represents a center thickness of the third lens.

5. An optical lens according to claim 1, characterized in that the optical lens satisfies the following conditional expression:

0.9<TTL/(f×tanθ)<1.1；

wherein, TTL represents an optical total length of the optical lens, f represents an effective focal length of the optical lens, and θ represents a half field angle of the optical lens.

6. An optical lens according to claim 1, characterized in that the optical lens satisfies the following conditional expression:

0.8<IH/(f×tanθ)<0.9；

wherein IH denotes an image height corresponding to a half field angle of the optical lens, f denotes an effective focal length of the optical lens, and θ denotes the half field angle of the optical lens.

7. An optical lens according to claim 1, characterized in that the optical lens satisfies the following conditional expression:

-2.0<f3/f<-0.5；

-5<(R31+R32)/(R31-R32)<-2；

where f3 denotes a focal length of the third lens, f denotes an effective focal length of the optical lens, R31 denotes a radius of curvature of an object-side surface of the third lens, and R32 denotes a radius of curvature of an image-side surface of the third lens.

8. An optical lens according to claim 1, characterized in that the optical lens satisfies the following conditional expression:

0.3<R41/f<1；

0.16<CT4/TTL<0.22；

wherein f represents an effective focal length of the optical lens, R41 represents a radius of curvature of an object side surface of the fourth lens element, CT4 represents a center thickness of the fourth lens element, and TTL represents an optical total length of the optical lens element.

9. An optical lens according to claim 1, characterized in that the optical lens satisfies the following conditional expression:

0.05<CT_1st/TTL<0.1；

wherein, CT_1stAnd the distance between the object side surface of the first lens and the diaphragm on the optical axis is represented, and TTL represents the total optical length of the optical lens.

10. An optical lens according to claim 1, characterized in that the optical lens satisfies the following conditional expression:

-0.5<R22/R21<0；

wherein R21 denotes a radius of curvature of an object-side surface of the second lens, and R22 denotes a radius of curvature of an image-side surface of the second lens.

11. An optical lens according to claim 1, characterized in that the optical lens satisfies the following conditional expression:

115°<FOV<135°；

TTL<3.8mm；

wherein, FOV represents the maximum field angle of the optical lens, TTL represents the optical total length of the optical lens.