CN117031709A

CN117031709A - Optical lens

Info

Publication number: CN117031709A
Application number: CN202311132787.2A
Authority: CN
Inventors: 谢先国; 谢雨辰; 章彬炜
Original assignee: Jiangxi Lianyi Optics Co Ltd
Current assignee: Jiangxi Lianyi Optics Co Ltd
Priority date: 2023-09-05
Filing date: 2023-09-05
Publication date: 2023-11-10
Anticipated expiration: 2043-09-05
Also published as: CN117031709B

Abstract

The invention discloses an optical lens, which sequentially comprises from an object side to an imaging surface along an optical axis: a diaphragm; the first lens with positive focal power has a convex object side surface and a convex image side surface; the second lens with negative focal power has a convex object side surface and a concave image side surface; a third lens with negative focal power, the object side surface of which is a concave surface; a fourth lens element with positive refractive power having a convex object-side surface at a paraxial region and a convex image-side surface; a fifth lens element with negative refractive power having a concave object-side surface at a paraxial region and a concave image-side surface at a paraxial region; the optical lens satisfies the following conditional expression: CT1/f is more than 0.26 and less than 0.30;0 < (R11+R12)/(R11-R12) < 0.5; wherein f represents an effective focal length of the optical lens, CT1 represents a center thickness of the first lens, R11 represents a radius of curvature of an object side surface of the first lens, and R12 represents a radius of curvature of an image side surface of the first lens. The optical lens provided by the invention has the advantages of small head and high pixel.

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 development of image sensing chip technology, the size of pixels is made smaller and smaller, and correspondingly, the requirement on the resolving power of matched cameras is also higher and higher.

The electronic product with the camera shooting function is in order to meet the market demand, not only is the analysis capability required to be strong, but also the characteristic of small head is required, and the screen occupation ratio of the lens in the electronic display screen is reduced, so that the aesthetic demand of a user is met.

Disclosure of Invention

Therefore, the present invention is directed to an optical lens having at least the advantages of small head and high pixel.

The invention provides an optical lens, which sequentially comprises from an object side to an imaging surface along an optical axis: a diaphragm; the first lens with positive focal power has a convex object side surface and a convex image side surface; the second lens with negative focal power has a convex object side surface and a concave image side surface; a third lens with negative focal power, the object side surface of which is a concave surface; a fourth lens element with positive refractive power having a convex object-side surface at a paraxial region and a convex image-side surface; a fifth lens element with negative refractive power having a concave object-side surface at a paraxial region and a concave image-side surface at a paraxial region; the optical lens satisfies the following conditional expression: CT1/f is more than 0.26 and less than 0.30;0 < (R11+R12)/(R11-R12) < 0.5; wherein f represents an effective focal length of the optical lens, CT1 represents a center thickness of the first lens, R11 represents a radius of curvature of an object side surface of the first lens, and R12 represents a radius of curvature of an image side surface of the first lens.

Compared with the prior art, the optical lens provided by the invention adopts five lenses with specific focal power, and the focal power and the lens shape of each lens are reasonably matched, and the diaphragm is arranged in front of the first lens, so that the optical lens can realize a small head structure on the premise of having enough imaging capability, and the current market demand can be met.

Drawings

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

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

Fig. 3 is a distortion graph of an optical lens according to a first embodiment of the present invention.

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

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

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

Fig. 7 is a field curvature chart of an optical lens according to a second embodiment of the present invention.

Fig. 8 is a distortion graph of an optical lens according to a second embodiment of the present invention.

Fig. 9 is an axial chromatic aberration diagram 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 according to a third embodiment of the present invention.

Fig. 12 is a field curve diagram 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 an axial chromatic aberration diagram 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.

Detailed Description

In order that the objects, features and advantages of the invention will be readily understood, a more particular description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. Several embodiments of the invention are presented in the figures. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Like reference numerals refer to like elements throughout the specification.

The embodiment of the invention provides an optical lens, which sequentially comprises the following components from an object side to an imaging surface along an optical axis: the optical centers of the diaphragm, the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the optical filter are positioned on the same straight line.

The first lens has positive focal power, and the object side surface of the first lens is a convex surface; the second lens has negative focal power; 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 concave surface at a paraxial region; the fourth lens has positive focal power, the object side surface of the fourth lens is a convex surface at the paraxial region, and the image side surface of the fourth lens is a convex surface; the fifth lens has negative focal power, the object side surface of the fifth lens is concave at a paraxial region, and the image side surface of the fifth lens is concave at the paraxial region; meanwhile, the first lens, the second lens, the third lens, the fourth lens and the fifth lens are all plastic aspheric lenses.

In some embodiments, the center thickness CT1 of the first lens and the effective focal length f of the optical lens satisfy: CT1/f is more than 0.26 and less than 0.30; meanwhile, the curvature radius R11 of the first lens object-side surface and the curvature radius R12 of the first lens image-side surface satisfy: and 0 < (R11+R12)/(R11-R12) < 0.5. The surface type of the first lens can be reasonably controlled by meeting the above conditional expression, so that light is reasonably converged, and can be effectively transmitted to a rear optical system, meanwhile, the head size of the optical lens is reduced, the balance between the small head and the high pixels of the optical lens is realized, and the screen occupation ratio of the optical lens applied to portable electronic equipment is reduced.

In some embodiments, the effective aperture DM11 of the first lens object-side surface and the effective aperture DM52 of the fifth lens image-side surface satisfy: 3.4 < DM52/DM11 < 3.6. The optical lens can have the structural characteristics of a small head part by meeting the above conditional expression.

In some embodiments, the effective focal length f2 of the second lens and the effective focal length f3 of the third lens satisfy: f2/f3 is more than 0.5 and less than 1.0; meanwhile, the effective focal length f3 of the third lens and the effective focal length f5 of the fifth lens satisfy: 6.0 < f3/f5 < 6.5. The optical powers of the second lens, the third lens and the fifth lens can be reasonably distributed by meeting the above conditional expression, and the imaging quality of the optical lens can be improved.

In some embodiments, the radius of curvature R22 of the image side of the second lens and the effective focal length f of the optical lens satisfy: r22/f is more than 0.2 and less than 1.0. The above conditional expression is satisfied, the surface shape of the image side surface of the second lens can be reasonably controlled, the improvement of the secondary spectrum is facilitated, and the imaging quality of the optical lens is improved.

In some embodiments, the effective focal length f of the optical lens and the radius of curvature R31 of the object-side surface of the third lens and the radius of curvature R32 of the image-side surface of the third lens satisfy: -1.0 < (R31+R32)/f < 0. The method meets the conditional expression, is favorable for apportioning the eccentric sensitivity of the third lens, improves the optimization space, and simultaneously can effectively correct the marginal field aberration and further improve the imaging capability of the optical lens.

In some embodiments, the effective focal length f of the optical lens and the radius of curvature R42 of the image side of the fourth lens satisfy: -4.5 < f/R42 < -3.0; meanwhile, the center thickness CT4 of the fourth lens element and the edge sagittal height SAG41 of the object side surface of the fourth lens element and the edge sagittal height SAG42 of the image side surface of the fourth lens element satisfy: -1.5 < (sag41+sag42)/CT 4 < -0.5; and the effective focal length f4 of the fourth lens and the curvature radius R41 of the fourth lens object-side surface satisfy: 0.2 < f4/R41 < 0.5. The method meets the above conditional expression, is favorable for reasonably controlling the shape of the fourth lens, improving the aberration of the edge field of view, improving the imaging quality, improving the internal anti-ghost image of the fourth lens and improving the imaging quality of the optical lens.

In some embodiments, the maximum half image height IH of the optical lens and the effective aperture DM52 of the image side of the fifth lens satisfy: IH/DM52 is more than 0.5 and less than 0.7; meanwhile, the radius of curvature R51 of the fifth lens object-side surface and the radius of curvature R52 of the fifth lens image-side surface satisfy: -0.2 < R52/R51 < 0. The above conditional expression is satisfied, which is beneficial to the realization of large target surface imaging of the optical lens.

In some embodiments, the center thickness CT5 of the fifth lens and the edge sagittal height SAG52 of the image side of the fifth lens satisfy: -8.0 < CT5/SAG52 < -2.0. The above conditional expression is satisfied, which is favorable for improving the secondary spectrum of the optical system, thereby further improving the imaging capability of the optical lens.

In some embodiments, the center thickness CT1 of the first lens and the center thickness CT2 of the second lens satisfy: CT1/CT2 is more than 3.4 and less than 3.7; meanwhile, the central thickness CT1 of the first lens, the central thickness CT2 of the second lens, the central thickness CT3 of the third lens and the central thickness CT4 of the fourth lens satisfy 2.1 < (CT 1+ CT2+ CT 3)/CT 4 < 2.4. The optical lens meets the above conditional expression, and can effectively shorten the total optical length and volume of the optical lens, so that the structure is more compact, and the miniaturization of the optical lens is realized.

In some embodiments, the combined focal length f12 of the first lens and the second lens and the effective focal length f of the optical lens satisfy: f12/f is more than 1.4 and less than 1.6; the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: TTL/f is less than 1.40 and less than 1.55. The method meets the above conditional expression, is favorable for distributing tolerance, improves optimization space, thereby improving imaging quality of the optical lens, simultaneously is favorable for shortening the total optical length of the optical lens, has more compact structure, and realizes miniaturization of the optical lens and equalization of high pixels.

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

The surface shape of the aspherical lens in each embodiment of the present invention satisfies the following equation:

the method comprises the steps of carrying out a first treatment on the surface of the Where z is the distance sagittal height from the aspherical surface vertex when the aspherical surface is at a position of height h in the optical axis direction, c is the paraxial curvature of the surface, k is the quadric coefficient, A _2i The aspherical surface profile coefficient of the 2 i-th order.

First embodiment

Referring to fig. 1, a schematic structural diagram of an optical lens 100 according to a first embodiment of the present invention is shown, where the optical lens 100 includes, in order from an object side to an imaging surface S13 along an optical axis: stop ST, first lens L1, second lens L2, third lens L3, fourth lens L4, fifth lens L5, and filter G1.

Specifically, the first lens element L1 is a plastic aspheric lens with positive refractive power, wherein an object-side surface S1 of the first lens element is a convex surface, and an image-side surface S2 of the first lens element is a convex surface; the second lens element L2 with negative refractive power is a plastic aspheric lens, wherein an object-side surface S3 of the second lens element is a convex surface, and an image-side surface S4 of the second lens element is a concave surface; the third lens element L3 is a plastic aspheric lens with negative refractive power, wherein an object-side surface S5 of the third lens element is a concave surface, and an image-side surface S6 of the third lens element is a concave surface at a paraxial region; the fourth lens element L4 is a plastic aspheric lens with positive refractive power, wherein an object-side surface S7 of the fourth lens element is convex at a paraxial region, and an image-side surface S8 of the fourth lens element is convex; the fifth lens element L5 is a plastic aspheric lens with negative refractive power, wherein an object-side surface S9 of the fifth lens element is concave at a paraxial region thereof, and an image-side surface S10 of the fifth lens element is concave at a paraxial region thereof; the object side surface of the filter G1 is S11, and the image side surface is S12.

The relevant parameters of each lens in the optical lens 100 provided in this embodiment are shown in table 1.

TABLE 1

The aspherical surface coefficients of the optical lens 100 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 chromatic aberration of the optical lens 100 are shown in fig. 2, 3, 4, and 5, respectively. As can be seen from fig. 2 to 5, the curvature of field is controlled within ±0.2mm, the optical distortion is controlled within ±2%, the axial chromatic aberration of the shortest wavelength and the maximum wavelength is controlled within ±0.02mm, and the vertical chromatic aberration of each wavelength with respect to the center wavelength in different fields of view is controlled within ±2.0 μm, indicating that the curvature of field, distortion 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 according to a second embodiment of the present invention is shown, and the optical lens 200 in the present embodiment has different surface types and thickness parameters compared to the optical lens 100 in the first embodiment.

The relevant parameters of each lens in the optical lens 200 provided in this embodiment are shown in table 3.

TABLE 3 Table 3

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

TABLE 4 Table 4

In the present embodiment, graphs of curvature of field, distortion, axial chromatic aberration, and vertical chromatic aberration of the optical lens 200 are shown in fig. 7, 8, 9, and 10, respectively. As can be seen from fig. 7 to 10, the curvature of field is controlled within ±0.12mm, the optical distortion is controlled within ±2%, the axial chromatic aberration of the shortest wavelength and the maximum wavelength is controlled within ±0.03mm, and the vertical chromatic aberration of each wavelength with respect to the center wavelength in different fields of view is controlled within ±1.0 μm, indicating that the curvature of field, distortion and chromatic aberration of the optical lens 200 are well corrected.

Third embodiment

Referring to fig. 11, a schematic structural diagram of an optical lens 300 according to a third embodiment of the present invention is shown, and the optical lens 300 in the present embodiment is different from the optical lens 100 in the first embodiment in terms of the surface type and thickness parameters of each lens.

The relevant parameters of each lens in the optical lens 300 provided in this embodiment are shown in table 5.

TABLE 5

The aspherical surface coefficients of the optical lens 300 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 chromatic aberration of the optical lens 300 are shown in fig. 12, 13, 14, and 15, respectively. As can be seen from fig. 12 to 15, the curvature of field is controlled within ±0.16mm, the optical distortion is controlled within ±1.5%, the axial chromatic aberration between the shortest wavelength and the maximum wavelength is controlled within ±0.025mm, and the vertical chromatic aberration of each wavelength with respect to the center wavelength in different fields of view is controlled within ±1.5 μm, which means that the curvature of field, distortion and chromatic aberration of the optical lens 300 are well corrected.

Table 7 is an optical characteristic corresponding to each of the above three embodiments, and mainly includes an optical total length TTL, a half image height IH, a maximum half field angle FOV, an f-number FNO, an effective focal length f of the optical lens, and a numerical value corresponding to each of the above conditional expressions.

TABLE 7

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

(1) The effective caliber value of the first lens is only within 1.5, so that the optical lens has the characteristic of a small head, and the portable electronic equipment (such as a mobile phone) provided with the optical lens can improve the screen occupation ratio and meet the market demand.

(2) Five plastic aspheric lenses with specific focal power are adopted, and through reasonable collocation of specific surface types and different focal powers, the optical lens has strong imaging capability and can meet the requirement of the current market on high-definition lenses.

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

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

Claims

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

a diaphragm;

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

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

a third lens with negative focal power, wherein the object side surface of the third lens is a concave surface;

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

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

the optical lens satisfies the following conditional expression:

0.26＜CT1/f＜0.30；

0＜(R11+R12)/(R11-R12)＜0.5；

wherein f represents an effective focal length of the optical lens, CT1 represents a center thickness of the first lens, R11 represents a radius of curvature of an object side surface of the first lens, and R12 represents a radius of curvature of an image side surface of the first lens.

2. The optical lens according to claim 1, wherein the optical lens satisfies the following conditional expression:

3.4＜DM52/DM11＜3.6；

wherein DM11 represents the effective aperture of the first lens object-side surface, and DM52 represents the effective aperture of the fifth lens image-side surface.

3. The optical lens according to claim 1, wherein the optical lens satisfies the following conditional expression:

0.5＜f2/f3＜1.0；

6.0＜f3/f5＜6.5；

wherein f2 represents an effective focal length of the second lens, f3 represents an effective focal length of the third lens, and f5 represents an effective focal length of the fifth lens.

4. The optical lens according to claim 1, wherein the optical lens satisfies the following conditional expression:

0.2＜R22/f＜1.0；

where f represents an effective focal length of the optical lens, and R22 represents a radius of curvature of the image side surface of the second lens.

5. The optical lens according to claim 1, wherein the optical lens satisfies the following conditional expression:

-1.0＜(R31+R32)/f＜0；

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

6. The optical lens according to claim 1, wherein the optical lens satisfies the following conditional expression:

-4.5＜f/R42＜-3.0；

-1.5＜(SAG41+SAG42)/CT4＜-0.5；

0.2＜f4/R41＜0.5；

wherein f represents an effective focal length of the optical lens, f4 represents an effective focal length of the fourth lens, R41 represents a radius of curvature of an object side surface of the fourth lens, R42 represents a radius of curvature of an image side surface of the fourth lens, CT4 represents a center thickness of the fourth lens, SAG41 represents an edge sagittal height of the object side surface of the fourth lens, and SAG42 represents an edge sagittal height of the image side surface of the fourth lens.

7. The optical lens according to claim 1, wherein the optical lens satisfies the following conditional expression:

0.5＜IH/DM52＜0.7；

-0.2＜R52/R51＜0；

wherein IH represents the maximum half image height of the optical lens, DM52 represents the effective caliber of the image side surface of the fifth lens, R51 represents the curvature radius of the object side surface of the fifth lens, and R52 represents the curvature radius of the image side surface of the fifth lens.

8. The optical lens according to claim 1, wherein the optical lens satisfies the following conditional expression:

-8.0＜CT5/SAG52＜-2.0；

where CT5 represents the center thickness of the fifth lens and SAG52 represents the edge sagittal height of the image side of the fifth lens.

9. The optical lens according to claim 1, wherein the optical lens satisfies the following conditional expression:

3.4＜CT1/CT2＜3.7；

2.1＜(CT1+CT2+CT3)/CT4＜2.4；

wherein CT1 represents the center thickness of the first lens, CT2 represents the center thickness of the second lens, CT3 represents the center thickness of the third lens, and CT4 represents the center thickness of the fourth lens.

10. The optical lens according to claim 1, wherein the optical lens satisfies the following conditional expression:

1.4＜f12/f＜1.6；

wherein f represents an effective focal length of the optical lens, and f12 represents a combined focal length of the first lens and the second lens.