CN115755344A

CN115755344A - Optical lens

Info

Publication number: CN115755344A
Application number: CN202211523176.6A
Authority: CN
Inventors: 章彬炜; 徐文; 曾昊杰
Original assignee: Jiangxi Lianyi Optics Co Ltd
Current assignee: Jiangxi Lianyi Optics Co Ltd
Priority date: 2022-12-01
Filing date: 2022-12-01
Publication date: 2023-03-07

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: the first lens with positive focal power has a convex object-side surface and a concave image-side surface; a diaphragm; the second lens with positive focal power has a convex object-side surface and a convex image-side surface; a third lens having a negative optical power; the fourth lens with positive focal power has a concave object-side surface and a convex image-side surface; a fifth lens element with negative optical power having a convex object-side surface at the paraxial region and a concave image-side surface at the paraxial region. The optical lens has the advantages of small head, large visual angle, small volume, small distortion and the like, and can meet the requirements of light and thin 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

With the increasing market competition, terminal manufacturers of various portable electronic devices have rapidly updated their own product technologies, and optical lenses are becoming one of the important components of portable electronic devices, and the technology replacement is also becoming faster and faster, and optical lenses have been developed from the first single pixel to lens imaging diversification. Among them, the optical lens with a large viewing angle has been widely used in electronic device terminals due to its advantages of wide shooting range, large depth of field, short focal length, etc., and has a wide market prospect.

At present, the wide-angle lens on the market mostly adopts more than 5 structural forms, the lens volume is large, and the wide-angle lens cannot well adapt to the trend of light and thin portable electronic equipment; meanwhile, the optical distortion of the conventional wide-angle lens is more than 10%, and the edge imaging picture has a large distortion phenomenon during lens imaging, so that the shooting experience of consumers is seriously influenced.

Disclosure of Invention

Therefore, an object of the present invention is to provide an optical lens having at least advantages of a small head and a large angle of view, so as to satisfy the higher image capturing requirements of consumers.

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

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 element having a positive refractive power, the object-side surface of which is convex and the image-side surface of which is concave; a diaphragm; the object side surface of the second lens is a convex surface, and the image side surface of the second lens is a convex surface; a third lens having a negative optical power; a fourth lens with positive 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 element with negative optical power has a convex object-side surface at a paraxial region and a concave image-side surface at a paraxial region.

Compared with the prior art, the optical lens provided by the invention only comprises 5 lenses with specific focal power and specific shape, and the arrangement of the position of the diaphragm is reasonable, so that the optical lens has the advantages of small head, large visual angle, small volume and small distortion, the light and thin requirements of portable electronic equipment can be met, the size of the head hole can be reduced, the phenomenon of imaging distortion at the edge of the lens can be improved, and the market competitiveness is greatly enhanced.

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 disclosure;

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

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

FIG. 4 is a graph of axial spherical aberration of an optical lens according to a first embodiment of the present invention;

FIG. 5 is a lateral 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 curve diagram of an optical lens according to a second embodiment of the present invention;

FIG. 9 is a graph of on-axis spherical aberration of an optical lens according to a second embodiment of the present invention;

FIG. 10 is a lateral 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 according to a third embodiment of the present invention;

FIG. 14 is a graph of on-axis spherical aberration of an optical lens according to a third embodiment of the present invention;

fig. 15 is a lateral 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 presented 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.

The first lens has positive focal power, and the object side surface of the first lens is a convex surface, and the image side surface of the first lens is a concave surface; the second lens has positive focal power, and the object side surface of the second lens is a convex surface, and the image side surface of the second lens is a convex surface; the third lens has negative focal power; the fourth lens has positive focal power, and 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 element has a negative power, with an object-side surface that is convex at a paraxial region and an image-side surface that is concave at a paraxial region.

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

15.20< R21/CT2<32.80；（1）

-6.60<R22/CT2<-5.80；（2）

wherein CT2 represents the center thickness of the second lens, R21 represents the radius of curvature of the object-side surface of the second lens, and R22 represents the radius of curvature of the image-side surface of the second lens. The shape of the second lens can be reasonably arranged to bear the positive focal power in a specific range, so that the deflection efficiency of light is improved, the volume of the optical lens is reduced, and the miniaturization of the lens is realized.

-1.0%< DIS < 2.5% ；（3）

100°< FOV <105°；（4）

wherein DIS represents a maximum optical distortion of the optical lens, and FOV represents a maximum field angle of the optical lens. The optical lens meets the conditional expressions (3) and (4), ensures that the optical lens has large-view imaging, simultaneously can weaken the phenomenon of imaging distortion of the marginal view field, and improves the imaging quality of the lens. If the condition (3) is exceeded, the marginal field of view generates a distortion phenomenon to a greater extent when the lens is used for imaging in a large field of view, and the imaging quality of the lens is influenced; if the value is lower than the conditional expression (4), the imaging field of view of the lens is weakened, which is not favorable for large-range imaging.

0.55< D1/D4 < 0.62 ；（5）

wherein D1 denotes an effective diameter of the first lens, and D4 denotes an effective diameter of the fourth lens. Satisfy conditional expression (5), can rationally arrange the difference in height of first lens and second lens, be favorable to the camera lens to have littleer head size, can effectively promote the ratio of occupying of screen.

1.99< f/ENPD<2.21 ；（6）

-0.01 <SAG31/R31<0.11；（7）

where f represents an effective focal length of the optical lens, ENPD represents an entrance pupil diameter of the optical lens, SAG31 represents a sagittal height of the third lens object-side surface, and R31 represents a radius of curvature of the third lens object-side surface. The shape and rise of the object side surface of the third lens on the dipped beam axis can be reasonably arranged to satisfy the conditional expressions (6) and (7), so that the improvement of the luminous flux of the lens is facilitated, and the lens can also clearly image in a low-light environment.

1.30 <（SAG11+SAG12）/ET1< 4.75 ；（8）

wherein SAG11 represents a saggital height of the first lens object side surface, SAG12 represents a saggital height of the first lens image side surface, and ET1 represents an edge thickness of the first lens. Satisfy conditional expression (8), the rise distribution of the first lens object side of can rationally arranging and like the side is favorable to reducing the sensitivity of first lens, promotes the production yield of camera lens.

1.80 < R21/f2 <3.55 ；（9）

where R21 represents a radius of curvature of an object-side surface of the second lens, and f2 represents an effective focal length of the second lens. Satisfy conditional expression (9), can rationally arrange the shape of second lens for the deflection efficiency behind the camera lens of light entering is favorable to shortening of camera lens optical total length, realizes the miniaturization of camera lens.

-0.16< ET3/R31<0.01 ；（10）

wherein ET3 represents an edge thickness of the third lens, and R31 represents a radius of curvature of an object-side surface of the third lens. Satisfy conditional expression (10), the focal power of the third lens of can rationally arranging is favorable to slowing down the trend of light deflection to reduce whole optical system's sensitivity, promote the yield of optical lens equipment.

0.50< f4/f <0.69 ；（11）

0.02< ET4/TTL <0.16 ；（12）

wherein f4 represents an effective focal length of the fourth lens, f represents an effective focal length of the optical lens, ET4 represents an edge thickness of the fourth lens, and TTL represents an optical total length of the optical lens. The shape and the edge thickness of the fourth lens can be reasonably controlled to bear reasonable positive focal power and accelerate the deflection trend of light rays when the conditional expressions (11) and (12) are met, and the miniaturization of the optical lens is realized.

0.40<（CT1+CT2+CT3）/(CT4+CT5) <1.05 ；（13）

wherein CT1 denotes a center thickness of the first lens, CT2 denotes a center thickness of the second lens, CT3 denotes a center thickness of the third lens, CT4 denotes a center thickness of the fourth lens, and CT5 denotes a center thickness of the fifth lens. The central thickness of each lens on the optical axis can be reasonably arranged by satisfying the conditional expression (13), and the optical lens is favorable for forming a compact structure.

1.35 < f12/f <2.26；（14）

wherein f12 represents a combined focal length of the first lens and the second lens, and f represents an effective focal length of the optical lens. The shape of the first lens and the shape of the second lens can be reasonably arranged when the conditional expression (14) is met, the deflection efficiency of light entering the lens is accelerated, and the optical total length of the lens is favorably shortened.

-3.65< f3/f <-2.10 ；（15）

wherein f3 represents an effective focal length of the third lens, and f represents an effective focal length of the optical lens. And the conditional expression (15) is satisfied, the focal power of the third lens can be reasonably arranged, the tendency of light deflection is favorably relieved, the sensitivity of the whole optical system is reduced, and the yield of optical lens assembly is improved.

-3.65< f5/R52 <-2.20 ；（16）

wherein f5 represents an effective focal length of the fifth lens, and R52 represents a radius of curvature of an image-side surface of the fifth lens. And the shape of the fifth lens can be reasonably arranged to meet the conditional expression (16), the projection height of light on an image plane is reduced, the correction of peripheral field aberration and coma aberration is facilitated, and the imaging quality of the optical lens is improved.

In some embodiments, the first lens, the second lens, the third lens, the fourth lens and the fifth lens may be all glass lenses or all plastic lenses, or may be a combination of plastic lenses and glass lenses.

In some embodiments, the first lens element, the second lens element, the third lens element, the fourth lens element and the fifth lens element are all plastic aspheric lens elements. By adopting the aspheric lens, the optical lens has better imaging quality, more compact structure and shorter optical total length.

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

In each embodiment of the present invention, the aspherical surface type of each lens satisfies the following equation:

；

wherein z is the distance rise from the aspheric surface vertex when the aspheric surface is at the position with the height h along the optical axis direction, c is the paraxial curvature of the surface, k is the quadric coefficient, A _2i The coefficient of the aspheric surface type 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 includes, in order from an object side to an image plane S13 along an optical axis: 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 element L1 is a plastic aspheric lens element with positive focal power, the object-side surface S1 of the first lens element is a convex surface, and the image-side surface S2 of the first lens element is a concave surface; the second lens L2 is a plastic aspheric lens with positive focal power, the object side surface S3 of the second lens is a convex surface, and the image side surface S4 of the second lens is a convex surface; the third lens element L3 is a plastic aspheric lens with negative power, the object-side surface S5 of the third lens element is convex at the paraxial region, and the image-side surface S6 of the third lens element is concave at the paraxial region; the fourth lens element L4 is a plastic aspheric lens with positive focal power, the object-side surface S7 of the fourth lens element is a concave surface, and the image-side surface S8 of the fourth lens element is a convex surface; the fifth lens element L5 is a plastic aspheric lens with negative power, 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 parameters of the optical lens 100 provided in the present embodiment are shown in table 1, where R represents the radius of curvature (unit: mm), d represents the distance between the optical surfaces (unit: mm), and n represents the distance between the optical surfaces (unit: mm) _d D-line refractive index, V, of the material _d Represents the abbe number of the material.

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

In this embodiment, the graphs of field curvature, distortion, on-axis point spherical aberration and lateral chromatic aberration of the optical lens 100 are shown in fig. 2, fig. 3, fig. 4 and fig. 5, respectively, and it can be seen from fig. 2 to fig. 5 that the field curvature is controlled within ± 0.05mm, the optical distortion is controlled within ± 1.3%, the axial chromatic aberration of the minimum wavelength and the maximum wavelength is controlled within ± 0.01mm, and the chromatic aberration of each wavelength relative to the central wavelength in different fields of view is controlled within ± 1.5 microns, which indicates that the field curvature, distortion, spherical aberration and chromatic aberration of the optical lens 100 are well corrected.

Second embodiment

Referring to fig. 6, a schematic structural diagram of an optical lens 200 provided in the present embodiment shows that a structure of the optical lens 200 in the present embodiment is substantially the same as the structure of the optical lens 100 in the first embodiment, and materials thereof are the same, but a center thickness and an edge thickness of each lens are changed.

Table 3 shows relevant parameters of each lens of the optical lens 200 provided in this embodiment.

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

In the present embodiment, the graphs of field curvature, distortion, on-axis point spherical aberration and lateral chromatic aberration of the optical lens 200 are shown in fig. 7, fig. 8, fig. 9 and fig. 10, respectively, and it can be seen from fig. 7 to fig. 10 that the field curvature is controlled within ± 0.05mm, the optical distortion is controlled within ± 2%, the axial chromatic aberration of the minimum wavelength and the maximum wavelength is controlled within ± 0.025mm, and the chromatic aberration of each wavelength with respect to the center wavelength in different fields of view is controlled within ± 1.5 microns, which indicates that the field curvature, distortion, spherical aberration and chromatic aberration of the optical lens 200 are well corrected.

Third embodiment

Referring to fig. 11, a schematic mechanism diagram of an optical lens 300 according to the present embodiment is shown, where the optical lens 300 in the present embodiment has a substantially same structural shape as the optical lens 100 in the first embodiment, but the shape of the third lens element on the paraxial region is changed.

The relevant parameters of each lens in the optical lens 300 in the present 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

In this embodiment, the graphs of field curvature, distortion, on-axis point spherical aberration and lateral chromatic aberration of the optical lens 300 are respectively shown in fig. 12, fig. 13, fig. 14 and fig. 15, and it can be seen from fig. 12 to fig. 15 that the field curvature is controlled within ± 0.05mm, the optical distortion is controlled within ± 2.1%, the axial chromatic aberration of the minimum wavelength and the maximum wavelength is controlled within ± 0.025mm, and the chromatic aberration of each wavelength with respect to the central wavelength in different fields of view is controlled within ± 2 microns, which shows that the field curvature, distortion, spherical aberration and chromatic aberration of the optical lens 300 are all well corrected.

Table 7 shows the optical characteristics corresponding to the three embodiments, which mainly includes the effective focal length f of the optical lens, the effective focal lengths f1, f2, f3, f4, and f5 of the lenses, the total optical length TTL, and the values corresponding to each of the above conditional expressions.

TABLE 7

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

(1) The optical lens provided by the invention adopts five lenses with specific surface shapes and reasonable focal power distribution, so that the optical lens has the advantages of small head, large visual angle, small volume, small distortion and the like.

(2) The optical lens provided by the invention has wider visual angle range and larger depth of field, can effectively ensure that the front and the rear scenes of the shot main body can be clearly reproduced on the picture, has strong front and rear feeling of the shot object, has perspective effect and can enhance the infectivity of the picture.

(3) The optical lens provided by the invention has small distortion, the distortion phenomenon is weak during edge imaging, and the imaging quality is favorably improved.

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 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, comprising, in order from an object side to an image plane along an optical axis:

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

a diaphragm;

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

a third lens having a negative optical power;

the fourth lens is provided with 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;

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.

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

15.20< R21/CT2<32.80；

-6.60< R22/CT2<-5.80；

wherein CT2 represents the center thickness of the second lens, R21 represents the radius of curvature of the object-side surface of the second lens, and R22 represents the radius of curvature of the image-side surface of the second lens.

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

-1.0%< DIS < 2.5% ；

100°< FOV <105°；

wherein DIS represents a maximum optical distortion of the optical lens, and FOV represents a maximum 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:

0.55< D1/D4 < 0.62 ；

wherein D1 denotes an effective diameter of the first lens, and D4 denotes an effective diameter of the fourth lens.

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

1.99< f/ENPD<2.21 ；

-0.01 <SAG31/R31<0.11；

where f represents an effective focal length of the optical lens, ENPD represents an entrance pupil diameter of the optical lens, SAG31 represents a sagittal height of the third lens object-side surface, and R31 represents a radius of curvature of the third lens object-side surface.

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

1.30 <（SAG11+SAG12）/ET1< 4.75 ；

wherein SAG11 represents the sagged height of the first lens object side surface, SAG12 represents the sagged height of the first lens image side surface, and ET1 represents the edge thickness of the first lens.

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

1.80 < R21/f2 <3.55 ；

where R21 represents a radius of curvature of an object-side surface of the second lens, and f2 represents an effective focal length of the second lens.

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

-0.16< ET3/R31<0.01；

wherein ET3 represents an edge thickness of the third lens, and R31 represents a radius of curvature of an object-side surface of the third lens.

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

0.50< f4/f <0.69 ；

0.02< ET4/TTL <0.16 ；

wherein f4 represents an effective focal length of the fourth lens, f represents an effective focal length of the optical lens, ET4 represents an edge thickness of the fourth lens, and TTL represents an optical total length of the optical lens.

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

0.40<（CT1+CT2+CT3）/(CT4+CT5) <1.05 ；

wherein CT1 denotes a center thickness of the first lens, CT2 denotes a center thickness of the second lens, CT3 denotes a center thickness of the third lens, CT4 denotes a center thickness of the fourth lens, and CT5 denotes a center thickness of the fifth lens.