CN114815186B

CN114815186B - Optical lens

Info

Publication number: CN114815186B
Application number: CN202210745657.5A
Authority: CN
Inventors: 凌兵兵; 鲍宇旻; 王克民
Original assignee: Jiangxi Lianchuang Electronic Co Ltd
Current assignee: Jiangxi Lianchuang Electronic Co Ltd
Priority date: 2022-06-29
Filing date: 2022-06-29
Publication date: 2022-11-01
Anticipated expiration: 2042-06-29
Also published as: CN114815186A

Abstract

The invention provides an optical lens, which comprises five lenses in total, wherein the five lenses are sequentially arranged from an object side to an imaging surface along an optical axis as follows: the first aspheric lens with negative focal power has a convex surface at the position close to the optical axis of the object side surface and a concave surface at the position close to the optical axis of the image side surface; the object side surface and the image side surface of the spherical second lens with positive focal power are convex surfaces; a diaphragm; a spherical third lens with positive focal power, wherein the object side surface and the image side surface of the spherical third lens are convex surfaces; the object side surface and the image side surface of the spherical fourth lens are convex surfaces; the spherical fifth lens with negative focal power has a concave object-side surface and a convex image-side surface; and the fourth lens and the fifth lens are mutually glued to form a cemented lens. The optical lens has the advantages of low dispersion, high relative illumination, high imaging quality and low cost.

Description

Optical lens

Technical Field

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

Background

With the development of automatic driving technology, ADAS (Advanced Driver assistance System) has become a standard configuration for many automobiles; the vehicle-mounted lens is used as a key device of the ADAS, can sense the surrounding road conditions of the vehicle in real time, and achieves the functions of forward collision early warning, lane deviation warning, pedestrian detection and the like.

At present, the demand for the number of vehicle-mounted lenses is increasing, and the reduction of the cost of the vehicle-mounted lenses and the improvement of the imaging quality are urgent needs in the automobile industry. For the traditional high-quality vehicle-mounted lens, in order to improve the imaging quality, a mode of adding lenses or using glass aspheric lenses is adopted, and the production cost is greatly improved by adding the lenses or using the glass aspheric lenses.

Disclosure of Invention

In view of the above problems, an objective of the present invention is to provide an optical lens having advantages of low chromatic dispersion, high relative illumination, high imaging quality and low cost.

In order to achieve the purpose, the technical scheme of the invention is as follows:

an optical lens system comprises five lenses, in order from an object side to an image plane along an optical axis:

the first aspheric lens with negative focal power has a convex object side surface near the optical axis and a concave image side surface near the optical axis;

the spherical second lens with positive focal power has a convex object side surface and a convex image side surface;

a diaphragm;

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

the object side surface and the image side surface of the spherical fourth lens are convex surfaces;

the spherical fifth lens with negative focal power has a concave object-side surface and a convex image-side surface;

the fourth lens and the fifth lens are mutually glued to form a cemented lens;

the effective focal length f of the optical lens and the real image height IH corresponding to the maximum field angle satisfy that: IH/f is more than 1.25 and less than 1.35;

an effective focal length f of the optical lens and a focal length f of the second lens₂Satisfies the following conditions: 1.9 < f₂/f＜2.1；

The height D of the optical lens on the object side surface of the first lens corresponding to the half field angle of 30 degrees passing through the center of the diaphragm₃₀Height D of the object-side surface of the first lens corresponding to the maximum half field angle through the center of the diaphragm_θSatisfies the following conditions: d is more than 0.6₃₀/D_θ＜0.9。

Preferably, the total optical length TTL and the effective focal length f of the optical lens satisfy: TTL/f is more than 4.5 and less than 5.5.

Preferably, the optical lens has a real image height IH corresponding to a half field angle of 30 °₃₀True image height IH corresponding to maximum half field angle_θSatisfies the following conditions: IH of 0.65%₃₀/IH_θ＜0.7。

Preferably, the effective focal length f of the optical lens and the rise Sag of the object side surface of the first lens are₁Satisfies the following conditions: sag of 0.3₁/f＜0.35。

Preferably, the effective focal length f of the optical lens and the focal length f of the first lens element₁And a center thickness CT of the first lens₁Respectively satisfy: -1.9 < f₁/f＜-1.7；0.6≤CT₁/f≤0.65。

Preferably, the focal length f of the second lens₂Focal length f of the third lens₃Satisfies the following conditions: 1.0 < f₂/f₃＜1.2。

Preferably, the focal length f of the fourth lens₄Focal length f of the fifth lens₅Satisfies the following conditions: -0.85 < f₄/f₅＜-0.7。

Preferably, the second lens has a radius of curvature R of the image side surface₄And the object side curvature radius R of the third lens₅Satisfies the following conditions: -1.1. Ltoreq.R₄/R₅＜-1.0。

Preferably, the third lens has an object-side radius of curvature R₅Radius of curvature R of image side₆Satisfies the following conditions: -1.0 < R₅/R₆＜-0.3。

Preferably, the combined focal length f of the first lens and the second lens₁₂A combined focal length f with the fourth lens and the fifth lens₄₅Satisfies the following conditions: f is not less than 0.95₁₂/f₄₅＜1.2。

Compared with the prior art, the invention has the beneficial effects that: the optical lens has the advantages of low chromatic dispersion, high relative illumination, high imaging quality and low cost through the combination of the lens shape and the focal power between the lenses in reasonable collocation.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

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 embodiment 1 of the present invention;

fig. 2 is a field curvature graph of the optical lens in embodiment 1 of the present invention;

FIG. 3 is a graph showing F-tan θ distortion of an optical lens in example 1 of the present invention;

fig. 4 is a graph showing a relative illuminance curve of the optical lens in embodiment 1 of the present invention;

fig. 5 is a MTF graph of an optical lens in embodiment 1 of the present invention;

fig. 6 is a graph showing axial aberration of the optical lens in embodiment 1 of the present invention;

FIG. 7 is a vertical axis chromatic aberration diagram of an optical lens in embodiment 1 of the present invention;

fig. 8 is a schematic structural diagram of an optical lens system according to embodiment 2 of the present invention;

FIG. 9 is a graph of curvature of field of an optical lens in embodiment 2 of the present invention;

FIG. 10 is a graph showing F-tan θ distortion of an optical lens in example 2 of the present invention;

fig. 11 is a graph showing a relative illumination of an optical lens in embodiment 2 of the present invention;

fig. 12 is a MTF graph of an optical lens in embodiment 2 of the present invention;

FIG. 13 is a graph showing axial aberration curves of the optical lens system according to embodiment 2 of the present invention;

FIG. 14 is a vertical axis chromatic aberration diagram of an optical lens in embodiment 2 of the present invention;

fig. 15 is a schematic structural diagram of an optical lens system according to embodiment 3 of the present invention;

FIG. 16 is a graph of curvature of field of an optical lens in embodiment 3 of the present invention;

FIG. 17 is a graph showing F-tan θ distortion of an optical lens in embodiment 3 of the present invention;

fig. 18 is a graph showing the relative illumination of the optical lens in embodiment 3 of the present invention;

fig. 19 is a MTF graph of an optical lens in embodiment 3 of the present invention;

FIG. 20 is a graph showing axial aberrations of an optical lens according to embodiment 3 of the present invention;

FIG. 21 is a vertical axis chromatic aberration diagram of an optical lens in embodiment 3 of the present invention;

fig. 22 is a schematic structural diagram of an optical lens system according to embodiment 4 of the present invention;

FIG. 23 is a graph of curvature of field of an optical lens in embodiment 4 of the present invention;

FIG. 24 is a graph showing F-tan θ distortion of an optical lens in embodiment 4 of the present invention;

fig. 25 is a graph showing the relative illuminance of the optical lens in embodiment 4 of the present invention;

fig. 26 is a MTF graph of an optical lens in embodiment 4 of the present invention;

FIG. 27 is a graph showing axial aberrations of an optical lens unit according to embodiment 4 of the present invention;

fig. 28 is a vertical axis chromatic aberration diagram of the optical lens in embodiment 4 of the present invention.

The following detailed description will further illustrate the invention in conjunction with the above-described figures.

Detailed Description

For a better understanding of the present application, various aspects of the present application will be described in more detail with reference to the accompanying drawings. It should be understood that the detailed description is merely illustrative of embodiments of the application and does not limit the scope of the application in any way. Like reference numerals refer to like elements throughout the specification. The expression "and/or" includes any and all combinations of one or more of the associated listed items.

It should be noted that in this specification, the expressions first, second, third, etc. are used only to distinguish one feature from another, and do not represent any limitation on the features. Thus, the first lens discussed below may also be referred to as the second lens or the third lens without departing from the teachings of the present invention.

In the drawings, the thickness, size, and shape of the lens have been slightly exaggerated for convenience of explanation. In particular, the shapes of the spherical or aspherical surfaces shown in the drawings are shown by way of example. That is, the shape of the spherical surface or the aspherical surface is not limited to the shape of the spherical surface or the aspherical surface shown in the drawings. The figures are purely diagrammatic and not drawn to scale.

Herein, the paraxial region refers to a region near the optical axis. If the lens surface is convex and the convex position is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the concave position is not defined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the object is called the object side surface of the lens, and the surface of each lens closest to the imaging surface is called the image side surface of the lens.

It will be further understood that the terms "comprises," "comprising," "has," "having," "includes" and/or "including," when used in this specification, specify the presence of stated features, elements, and/or components, but do not preclude the presence or addition of one or more other features, elements, components, and/or groups thereof. Moreover, when a statement such as "at least one of" appears after the list of listed features, that the entirety of the listed features is modified rather than modifying individual elements in the list. Furthermore, the use of "may" mean "one or more embodiments of the application" when describing embodiments of the application. Also, the term "exemplary" is intended to refer to an example or illustration.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present application will be described in detail below with reference to the embodiments with reference to the attached drawings.

An optical lens according to an embodiment of the present application includes, in order from an object side to an image side: the lens comprises a first lens, a second lens, a diaphragm, a third lens, a fourth lens and a fifth lens.

In some embodiments, the first lens may have negative focal power and a convex-concave shape, which can achieve a large angular resolution of a central field of view of the optical lens, and at the same time, can collect light rays of a peripheral field of view as much as possible to enter the optical lens, and increase the amount of transmitted light to achieve a high relative illumination of a full field of view. On the other hand, the direction trend of marginal field of view light can be fixed, the direction trend is close to parallel with the optical axis, the imaging aberration of marginal light is reduced, and the imaging quality of the optical lens is improved.

In some embodiments, the second lens element may have a positive focal power and a double-convex surface type, which is beneficial for light to stably enter the rear optical system, and improves the imaging quality of the optical lens. Meanwhile, the working caliber of the second lens can be reduced, so that the miniaturization of the volume at the rear end of the optical lens is facilitated.

In some embodiments, the third lens element may have a positive focal power and a double-convex surface type, which is beneficial to the convergence of light rays of a large-aperture lens, improves the relative illumination of the peripheral field of view, and simultaneously effectively controls the total optical length to reduce the volume of the optical lens; and various aberrations generated by the third lens can be reduced, and the imaging quality of the optical lens is improved.

In some embodiments, the fourth lens element may have a positive refractive power and a double-convex shape, so as to balance various aberrations of the optical lens, make the trend of the rear light rays smoother, suppress the angle of the marginal field of view incident on the imaging plane, effectively transmit more light beams to the imaging plane, and improve the imaging quality of the optical lens.

In some embodiments, the fifth lens element may have a negative focal power and a concave-convex surface shape, which is beneficial to improving the light converging capability of the peripheral field of view, improving the relative illumination of the peripheral field of view, and effectively controlling the total optical length to reduce the volume of the optical lens, thereby being beneficial to the miniaturization of the optical lens.

In some embodiments, the fourth lens and the fifth lens can be cemented to form a cemented lens, wherein the lens with positive focal power can be made of a material with low refractive index, which helps to reduce the air space between the lenses, so that the whole optical lens is more compact, and at the same time, the chromatic aberration of the optical lens can be effectively corrected, and the decentration sensitivity of the optical lens can be reduced; in addition, the aberration of the optical lens can be balanced, and the imaging quality of the optical lens can be improved; in addition, the assembly sensitivity of the optical lens can be reduced, the processing difficulty of the optical lens is further reduced, and the assembly yield of the optical lens is improved.

In some embodiments, the first lens is a glass aspheric lens, the inflection point is arranged at a half field angle of 30 ° of the object-side surface of the first lens, and the inclination angle of the surface of the object-side surface of the first lens is continuously reduced in an area within the range of the half field angle of 30 °, so that the gradual change of the surface type of the object-side surface of the first lens is gentle, and the inflection phenomenon occurs. The first lens is arranged in the special aspheric surface shape, so that the central view field angular resolution is greatly improved, meanwhile, special distortion is provided for the lens, the distortion of the lens in a small view field angle range is obviously increased, and the special algorithm requirement of a vehicle-mounted system is more favorably met.

In some embodiments, the second lens, the third lens, the fourth lens, and the fifth lens are glass spherical lenses. Compared with a plastic lens, the optical lens has the advantages that the imaging quality of the optical lens can be improved, and the influence of temperature difference on the performance of the lens can be reduced; compared with the glass aspheric lens, the imaging quality of partial edge field angles is sacrificed, but the production cost can be obviously reduced, and the yield of the optical lens is improved.

In some embodiments, a diaphragm for limiting the light beam may be disposed between the second lens and the third lens, which can reduce the generation of astigmatism of the optical lens, and is favorable for converging the light entering the optical system, and reducing the rear aperture of the optical lens.

In some embodiments, the object-side surface of the lens behind the diaphragm is a convex surface, which is beneficial to improving the relative illumination of the optical lens, so that the brightness of the optical lens at the image plane is improved.

In some embodiments, the aperture value FNO of the optical lens satisfies: FNO < 1.55. The range is met, the large aperture characteristic is facilitated to be realized, and more incident rays are provided for the optical lens.

In some embodiments, the total optical length TTL and the effective focal length f of the optical lens satisfy: TTL/f is more than 4.5 and less than 5.5. The range is met, the length of the lens can be effectively limited, and the miniaturization of the optical lens is facilitated.

In some embodiments, the real image height IH corresponding to the maximum field angle and the effective focal length f of the optical lens satisfy: IH/f is more than 1.25 and less than 1.35. Satisfying the above range, the optical lens can not only give consideration to the large image plane characteristics, but also have excellent imaging quality.

In some embodiments, the optical back focus BFL and the effective focal length f of the optical lens satisfy: BFL/f is not less than 0.65. Satisfy above-mentioned scope, be favorable to obtaining easily assembling optics back focal length, reduce the camera module assembly process degree of difficulty.

In some embodiments, the optical lens has a real image height IH corresponding to a half field angle of 30 °₃₀True image height IH corresponding to maximum half field angle_θSatisfies the following conditions: IH of 0.65₃₀/IH_θIs less than 0.7. The imaging range is larger, the number of pixel points occupied by the corresponding chip surface is larger, and therefore more remote detailed information can be obtained. Meanwhile, the aberration correction difficulty of the central field of view of the optical lens can be reduced, so that the aberration of the lens depending on the diaphragm can be reduced.

In some embodiments, the height D of the optical lens at the object-side surface of the first lens corresponding to a half field angle of 30 ° through the center of the stop₃₀Height D of object-side surface of first lens corresponding to maximum half field angle passing through center of diaphragm_θSatisfies the following conditions: d is more than 0.6₃₀/D_θIs less than 0.9. Satisfy above-mentioned scope, adjusted by different degree after the light gets into first lens for the height ratio of central visual field light at first lens object side face is far higher than marginal visual field light, also through adjusting the height of the light that different visual fields pass through the diaphragm center at first lens object side face, thereby more be favorable to controlling the height of different visual fields focus at the imaging. Meanwhile, the aberration correction difficulty of the central field of view of the optical lens can be reduced, so that the aberration of the lens depending on the diaphragm can be reduced.

In some embodiments, the effective focal length f of the optical lens and the rise Sag of the object-side surface of the first lens₁Satisfies the following conditions: sag of 0.3₁The/f is less than 0.35. The imaging range of the central field of view is larger in the whole imaging range when the imaging range of the central field of view is matched with a chip with the same size, so that the imaging effect of a remote object is higher, more detailed information can be obtained, and the imaging range is more suitable for the use characteristics of a front-view lens of an ADAS system. Meanwhile, the central field angle light ray can be reducedThe deflection angle reduces the aberration correction difficulty of the central field of view of the optical lens, so as to reduce the lens correction aberration depending on the diaphragm.

In some embodiments, the effective focal length f of the optical lens and the focal length f of the first lens are different₁Satisfies the following conditions: -1.9 < f₁And/f < -1.7. Satisfying above-mentioned scope, can making first lens have appropriate negative power, be favorable to making incident ray refraction angle change comparatively alleviate, avoid refraction change too strong and produce too much aberration, help more light to get into rear lens simultaneously and promote relative illuminance.

In some embodiments, the effective focal length f of the optical lens and the focal length f of the second lens₂Satisfies the following conditions: 1.9 < f₂The/f is less than 2.1. Satisfying above-mentioned scope, can making the second lens have appropriate positive focal power, be favorable to the smooth transition of light, can correct the aberration that light produced through the excessive deflection of first lens simultaneously, promote optical lens's image quality.

In some embodiments, the effective focal length f of the optical lens and the focal length f of the third lens are₃Satisfies the following conditions: 1.7 < f₃The/f is less than or equal to 2.0. The third lens has proper positive focal power, so that the included angle between the normal of the object side surface and the image side surface and the incident light is small, the generation of high-order aberration is inhibited, and the imaging quality of the optical lens is improved.

In some embodiments, the focal length f of the second lens₂Focal length f of the third lens₃Satisfies the following conditions: 1.0 < f₂/f₃Is less than 1.2. Satisfy above-mentioned scope, can control the focus of second lens and third lens, make it more be close, be favorable to the light to pass through smoothly, promote optical lens's imaging quality.

In some embodiments, the focal length f of the fourth lens₄Focal length f of the fifth lens₅Satisfies the following conditions: -0.85 < f₄/f₅< -0.7. Satisfy above-mentioned scope, can account for the ratio through the focus that rationally sets up the cemented lens that fourth lens and fifth lens are constituteed, can effectively promote the achromatism ability of fourth, fifth lens, let the more even image plane that enters into of light through cemented lens to promoteAnd the imaging quality of the optical lens.

In some embodiments, the combined focal length f of the first and second lenses₁₂Combined focal length f with fourth and fifth lenses₄₅Satisfies the following conditions: f is not less than 0.95₁₂/f₄₅Is less than 1.2. Satisfy above-mentioned scope, can control the focus of lens around the diaphragm, make it more be close, be favorable to the light smooth transition, promote optical lens's imaging quality.

In some embodiments, the first lens object side radius of curvature R₁Radius of curvature R of image side surface₂Satisfies the following conditions: 2.0 < R₁/R₂Less than or equal to 2.4. Satisfy above-mentioned scope, can balance first lens self effectively and produce spherical aberration and coma, promote optical lens's imaging quality.

In some embodiments, the second lens has a radius of curvature of the object side R₃Radius of curvature R of image side₄Satisfies the following conditions: -10.0 < R₃/R₄< -5.0. The optical lens system can effectively reduce the influence of the field curvature and astigmatism generated by the second lens on the optical lens and improve the imaging quality of the optical lens.

In some embodiments, the second lens has a radius of curvature of image side R₄And the object side radius of curvature R of the third lens₅Satisfies the following conditions: -1.1. Ltoreq.R₄/R₅< -1.0. The shape of the image side surface of the second lens and the shape of the object side surface of the third lens can be controlled to be closer to a symmetrical structure, so that the field curvature of the optical lens can be effectively balanced, and the imaging quality of the optical lens is improved.

In some embodiments, the third lens has a radius of curvature of the object side R₅Radius of curvature R of image side surface₆Satisfies the following conditions: -1.0 < R₅/R₆< -0.3. Satisfy above-mentioned scope, can control the shape of third lens object side and image side face, reduce spherical aberration, coma and the distortion that third lens self produced and to optical lens's influence, promote optical lens's image quality.

In some embodiments, the second lens object side radius of curvature R₃Distance CT between the first lens and the second lens on the optical axis₁₂Satisfy the requirements of：17.0＜R₃/CT₁₂Is less than 34.0. The optical lens meets the above range, the light focusing position after the reflection of the object side surface of the second lens is positioned behind the imaging surface, the design ghost of the optical lens can be effectively improved, and the imaging quality of the optical lens is improved.

In some embodiments, the third lens has a radius of curvature of the object side R₅Distance CT on optical axis from the second lens and the third lens₂₃Satisfies the following conditions: r is more than 3.2₅/CT₂₃Is less than 8.5. Satisfy above-mentioned scope, can make the light focus position after the third lens body object side reflection be located the imaging plane rear, can effectively improve optical lens's design ghost, promote optical lens's imaging quality.

In some embodiments, the effective focal length f of the optical lens and the center thickness CT of the first lens₁Satisfies the following conditions: 0.6 or less CT₁The/f is less than or equal to 0.65. The height of the light rays passing through the center of the diaphragm in different fields of view on the object side surface of the first lens can be controlled.

In some embodiments, the effective focal length f of the optical lens and the center thickness CT of the second lens₂Satisfies the following conditions: CT of 1.3 or less₂The/f is less than or equal to 1.64. Satisfy above-mentioned scope, through setting up thicker second lens for light gently passes through, promotes optical lens's imaging quality.

In some embodiments, the effective focal length f of the optical lens and the center thickness CT of the third lens₃Satisfies the following conditions: 0.49 or less CT₃The/f is less than or equal to 0.65. The above range is satisfied, and the overall size of the optical lens is favorably reduced.

In some embodiments, the refractive index temperature drift coefficient dN of the second lens₂/dT₂Refractive index temperature drift coefficient dN of third lens₃/dT₃Satisfies the following conditions: -15X 10^-6/℃＜dN₂/dT₂+dN₃/dT₃＜-10×10^-6/. Degree.C.. The temperature compensation method meets the range, can effectively compensate the influence of temperature change on the effective focal length of the optical lens, and improves the stability of lens resolving power at different temperatures.

In order to make the system have better optical performance, a plurality of aspheric lenses are adopted in the lens, and the shapes of the aspheric surfaces of the optical lens satisfy the following equation:

；

wherein z is the distance between the curved surface and the vertex of the curved surface in the direction of the optical axis, h is the distance between the optical axis and the curved surface, C is the curvature of the vertex of the curved surface, K is the coefficient of the quadric surface, and A, B, C, D, E and F are the coefficients of the second order, the fourth order, the sixth order, the eighth order, the tenth order and the twelfth order respectively.

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.

Example 1

Referring to fig. 1, a schematic structural diagram of an optical lens system according to embodiment 1 of the present invention is shown, the optical lens system sequentially includes, from an object side to an image plane along an optical axis: a first lens L1, a second lens L2, a diaphragm ST, a third lens L3, a fourth lens L4, a fifth lens L5, an optical filter G1, and a cover glass G2.

The first lens element L1 has negative power, and has a convex object-side surface S1 near the optical axis and a concave image-side surface S2 near the optical axis;

the second lens L2 has positive focal power, and both the object side surface S3 and the image side surface S4 are convex surfaces;

a diaphragm ST;

the third lens L3 has positive focal power, and both the object side surface S5 and the image side surface S6 are convex surfaces;

the fourth lens L4 has positive focal power, and both the object side surface S7 and the image side surface S8 are convex surfaces;

the fifth lens L5 has negative focal power, and the object-side surface S9 is a concave surface, and the image-side surface S10 is a convex surface;

the fourth lens L4 and the fifth lens L5 can be glued to form a cemented lens;

the object side surface S11 and the image side surface S12 of the optical filter G1 are both planes;

the object side surface S13 and the image side surface S14 of the protective glass G2 are both planes;

the image formation surface S15 is a plane.

The relevant parameters of each lens in the optical lens in example 1 are shown in table 1-1.

TABLE 1-1

The surface shape parameters of the aspherical lens of the optical lens in example 1 are shown in table 1-2.

Tables 1 to 2

In this embodiment, the curvature of field curve, F-tan θ distortion, relative illumination, MTF, axial aberration, and homeotropic aberration of the optical lens are shown in fig. 2, 3, 4, 5, 6, and 7, respectively.

Fig. 2 shows a field curvature curve of example 1, which indicates the degree of curvature of light rays of different wavelengths on a meridional image plane and a sagittal image plane, with the horizontal axis indicating a shift amount (unit: mm) and the vertical axis indicating a half field angle (unit: °). As can be seen from the figure, the field curvature of the meridional image plane and the sagittal image plane is controlled within +/-0.02 mm, which shows that the optical lens can excellently correct the field curvature.

Fig. 3 shows an F-tan θ distortion curve of example 1, which shows the F-tan θ distortion of light rays of different wavelengths at different image heights on an image forming plane, with the horizontal axis showing the F-tan θ distortion (unit:%) and the vertical axis showing the half field angle (unit:%). As can be seen from the figure, the F-Tan theta distortion of the optical lens is controlled within-65% -0, the trend of the distortion curve is smooth, the image compression in the edge large-angle area is smooth, the definition of the expanded image is effectively improved, and the optical lens can better correct the F-Tan theta distortion.

Fig. 4 shows a relative illuminance curve of example 1, which represents relative illuminance values at different angles of field of view on the imaging plane, with the horizontal axis representing the half field angle (unit: °) and the vertical axis representing the relative illuminance (unit:%). As can be seen from the figure, the relative illuminance value of the optical lens is still greater than 90% at the maximum half field angle, indicating that the optical lens has excellent relative illuminance.

Fig. 5 shows MTF (modulation transfer function) graphs of embodiment 1, which represent lens imaging modulation degrees of different spatial frequencies for each field of view, with the horizontal axis representing the spatial frequency (unit: lp/mm) and the vertical axis representing MTF values. It can be seen from the figure that the MTF values of the present embodiment are both above 0.3 in the full field of view, and in the range of 0 to 160lp/mm, the MTF curves decrease uniformly and smoothly in the process from the center to the edge field of view, and have excellent imaging quality and excellent detail resolution capability in both low and high frequencies.

Fig. 6 shows an axial aberration curve of example 1, which represents the aberration on the optical axis at the imaging plane for each wavelength, with the horizontal axis representing the axial aberration value (unit: mm) and the vertical axis representing the normalized pupil radius. As can be seen from the figure, the offset of the axial aberration is controlled within ± 0.02mm, which indicates that the optical lens can excellently correct the axial aberration.

Fig. 7 shows a vertical axis chromatic aberration curve of example 1, which shows chromatic aberration at different image heights on an image forming plane for each wavelength with respect to a center wavelength (0.55 μm), the horizontal axis shows a vertical axis chromatic aberration value (unit: μm) for each wavelength with respect to the center wavelength, and the vertical axis shows a normalized angle of view. As can be seen from the figure, the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within +/-4 mu m, which shows that the optical lens can effectively correct the chromatic aberration of the marginal field of view and the secondary spectrum of the whole image plane.

Example 2

Referring to fig. 8, a schematic structural diagram of an optical lens system according to embodiment 2 of the present invention is shown, the optical lens system sequentially includes, from an object side to an image plane along an optical axis: a first lens L1, a second lens L2, a diaphragm ST, a third lens L3, a fourth lens L4, a fifth lens L5, an optical filter G1, and a cover glass G2.

The first lens element L1 has negative power, and has a convex object-side surface S1 at a paraxial region thereof and a concave image-side surface S2 at a paraxial region thereof;

a diaphragm ST;

the fifth lens L5 has negative focal power, and the object side surface S9 is a concave surface, and the image side surface S10 is a convex surface;

the fourth lens L4 and the fifth lens L5 may be cemented to constitute a cemented lens.

Relevant parameters of each lens in the optical lens in embodiment 2 are shown in table 2-1.

TABLE 2-1

The parameters of the surface shape of the aspherical lens of the optical lens in example 2 are shown in table 2-2.

Tables 2 to 2

In this embodiment, the curvature of field curve, F-tan θ distortion curve, relative illumination curve, MTF curve, axial aberration curve, and vertical axis chromatic aberration curve of the optical lens are respectively shown in fig. 9, 10, 11, 12, 13, and 14.

Fig. 9 shows a field curvature curve of example 2, which shows the degree of curvature of light rays of different wavelengths on a meridional image plane and a sagittal image plane, with the horizontal axis representing the amount of displacement (unit: mm) and the vertical axis representing the half field angle (unit: °). As can be seen from the figure, the field curvature of the meridional image plane and the sagittal image plane is controlled within +/-0.02 mm, which shows that the optical lens can excellently correct the field curvature.

Fig. 10 shows an F-tan θ distortion curve of example 2, which shows F-tan θ distortions at different image heights on an image forming plane for light rays of different wavelengths, with the abscissa representing the F-tan θ distortion (unit:%) and the ordinate representing the half field angle (unit: °). As can be seen from the figure, the F-Tan theta distortion of the optical lens is controlled within-65% -0, the trend of the distortion curve is smooth, the image compression in the edge large-angle area is smooth, the definition of the expanded image is effectively improved, and the optical lens can better correct the F-Tan theta distortion.

Fig. 11 shows a relative illuminance curve of example 2, which represents relative illuminance values at different angles of field of view on the imaging plane, with the horizontal axis representing the half field angle (unit: °), and the vertical axis representing the relative illuminance (unit:%). As can be seen from the figure, the relative illuminance value of the optical lens is still greater than 90% at the maximum half field angle, indicating that the optical lens has excellent relative illuminance.

Fig. 12 shows MTF (modulation transfer function) graphs of embodiment 2, which represent the degree of modulation of lens imaging at different spatial frequencies for each field of view, with the horizontal axis representing the spatial frequency (unit: lp/mm) and the vertical axis representing the MTF value. As can be seen from the figure, the MTF value of the present embodiment is above 0.3 in the whole field of view, and in the range of 0-160 lp/mm, the MTF curve is uniformly and smoothly dropped in the process from the center to the edge field of view, and the image quality and the detail resolution capability are excellent in both the low frequency and the high frequency.

Fig. 13 shows an axial aberration curve of example 2, which represents the aberration on the optical axis at the imaging plane for each wavelength, with the horizontal axis representing the axial aberration value (unit: mm) and the vertical axis representing the normalized pupil radius. As can be seen from the figure, the offset of the axial aberration is controlled within ± 0.02mm, which indicates that the optical lens can excellently correct the axial aberration.

Fig. 14 shows a vertical axis chromatic aberration curve of example 2, which shows chromatic aberration at different image heights on an image forming plane for each wavelength with respect to a center wavelength (0.55 μm), the horizontal axis shows a vertical axis chromatic aberration value (unit: μm) for each wavelength with respect to the center wavelength, and the vertical axis shows a normalized angle of view. As can be seen from the figure, the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within +/-3 mu m, which shows that the optical lens can effectively correct the chromatic aberration of the marginal field of view and the secondary spectrum of the whole image plane.

Example 3

Referring to fig. 15, a schematic structural diagram of an optical lens system according to embodiment 3 of the present invention is shown, the optical lens system sequentially includes, from an object side to an image plane along an optical axis: a first lens L1, a second lens L2, a stop ST, a third lens L3, a fourth lens L4, a fifth lens L5, an optical filter G1, and a cover glass G2.

a diaphragm ST;

the fourth lens L4 has positive focal power, and both the object-side surface S7 and the image-side surface S8 are convex surfaces;

The relevant parameters of each lens in the optical lens in example 3 are shown in table 3-1.

TABLE 3-1

The surface shape parameters of the aspherical lens of the optical lens in example 3 are shown in table 3-2.

TABLE 3-2

In the present embodiment, a field curvature graph, an F-tan θ distortion curve, a relative illuminance graph, an MTF graph, an axial aberration graph, and a vertical axis chromatic aberration graph of the optical lens are shown in fig. 16, 17, 18, 19, 20, and 21, respectively.

Fig. 16 shows a field curvature curve of example 3, which shows the degree of curvature of light rays of different wavelengths on a meridional image plane and a sagittal image plane, with the horizontal axis representing the amount of displacement (unit: mm) and the vertical axis representing the half field angle (unit: °). As can be seen from the figure, the field curvature of the meridional image plane and the sagittal image plane is controlled within +/-0.04 mm, which shows that the optical lens can excellently correct the field curvature.

Fig. 17 shows an F-tan θ distortion curve of example 3, which shows F-tan θ distortions at different image heights on an image forming plane for light rays of different wavelengths, with the abscissa representing the F-tan θ distortion (unit:%) and the ordinate representing the half field angle (unit: °). As can be seen from the figure, the F-Tan theta distortion of the optical lens is controlled within-65% -0, the trend of the distortion curve is smooth, the image compression in the edge large-angle area is smooth, the definition of the expanded image is effectively improved, and the optical lens can better correct the F-Tan theta distortion.

Fig. 18 shows a relative illuminance curve of example 3, which represents relative illuminance values at different angles of field of view on the imaging plane, with the horizontal axis representing the half field angle (unit: °) and the vertical axis representing the relative illuminance (unit:%). As can be seen from the figure, the relative luminance value of the optical lens is still greater than 90% at the maximum half field angle, indicating that the optical lens has excellent relative luminance.

Fig. 19 shows MTF (modulation transfer function) graphs of embodiment 3, which represent the degree of modulation of lens imaging at different spatial frequencies for each field of view, with the horizontal axis representing the spatial frequency (unit: lp/mm) and the vertical axis representing the MTF value. As can be seen from the figure, the MTF value of the present embodiment is above 0.3 in the whole field of view, and in the range of 0-160 lp/mm, the MTF curve is uniformly and smoothly dropped in the process from the center to the edge field of view, and the image quality and the detail resolution capability are excellent in both the low frequency and the high frequency.

Fig. 20 shows an axial aberration curve of example 3, which represents the aberration on the optical axis at the imaging plane for each wavelength, with the horizontal axis representing the axial aberration value (unit: mm) and the vertical axis representing the normalized pupil radius. As can be seen from the figure, the offset of the axial aberration is controlled within ± 0.02mm, which indicates that the optical lens can excellently correct the axial aberration.

Fig. 21 shows a vertical axis chromatic aberration curve of example 3, which shows chromatic aberration at different image heights on an image forming plane for each wavelength with respect to a center wavelength (0.55 μm), the horizontal axis shows a vertical axis chromatic aberration value (unit: μm) for each wavelength with respect to the center wavelength, and the vertical axis shows a normalized angle of view. As can be seen from the figure, the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within +/-6 mu m, which shows that the optical lens can effectively correct the chromatic aberration of the marginal field of view and the secondary spectrum of the whole image plane.

Example 4

Referring to fig. 22, a schematic structural diagram of an optical lens system according to embodiment 4 of the present invention is shown, the optical lens system sequentially includes, from an object side to an image plane along an optical axis: a first lens L1, a second lens L2, a diaphragm ST, a third lens L3, a fourth lens L4, a fifth lens L5, an optical filter G1, and a cover glass G2.

a diaphragm ST;

The relevant parameters of each lens in the optical lens in example 4 are shown in table 4-1.

TABLE 4-1

The surface shape parameters of the aspherical lens of the optical lens in example 4 are shown in table 4-2.

TABLE 4-2

Fig. 23 shows a field curvature curve of example 4, which shows the degree of curvature of light rays of different wavelengths on a meridional image plane and a sagittal image plane, with the horizontal axis representing the amount of displacement (unit: mm) and the vertical axis representing the half field angle (unit: °). As can be seen from the figure, the field curvature of the meridional image plane and the sagittal image plane is controlled within +/-0.03 mm, which shows that the optical lens can excellently correct the field curvature.

Fig. 24 shows an F-Tan θ distortion curve of example 4, which shows the F-Tan θ distortion at different image heights on the image forming plane for light rays of different wavelengths, with the horizontal axis showing the F-Tan θ distortion (unit:%) and the vertical axis showing the half field angle (unit: °). As can be seen from the figure, the F-Tan theta distortion of the optical lens is controlled within minus 65% -0, the trend of the distortion curve is smooth, the image compression of the edge large-angle area is smooth, the definition of the expanded image is effectively improved, and the optical lens can better correct the F-Tan theta distortion.

Fig. 25 shows a relative illuminance curve of example 4, which represents relative illuminance values at different angles of field of view on the imaging plane, with the horizontal axis representing the half field angle (unit: °), and the vertical axis representing the relative illuminance (unit:%). As can be seen from the figure, the relative illuminance value of the optical lens is still greater than 90% at the maximum half field angle, indicating that the optical lens has excellent relative illuminance.

Fig. 26 shows MTF (modulation transfer function) graphs of embodiment 4, which represent the degree of modulation of lens imaging at different spatial frequencies for each field of view, with the horizontal axis representing the spatial frequency (unit: lp/mm) and the vertical axis representing the MTF value. As can be seen from the graph, the MTF values of the present embodiment are each 0.5 or more in the half field, 0.3 or more in the full field, and in the range of 0 to 160lp/mm, the MTF curve uniformly and smoothly decreases in the process from the center to the edge field, and has excellent imaging quality and excellent detail resolving power in both low and high frequencies.

Fig. 27 shows an axial aberration curve of example 4, which represents the aberration on the optical axis at the imaging plane for each wavelength, with the horizontal axis representing the axial aberration value (unit: mm) and the vertical axis representing the normalized pupil radius. As can be seen from the figure, the offset of the axial aberration is controlled within +/-0.02 mm, which shows that the optical lens can excellently correct the axial aberration.

Fig. 28 shows a vertical axis chromatic aberration curve of example 4, which shows chromatic aberration at different image heights on an image forming plane for each wavelength with respect to a center wavelength (0.55 μm), the horizontal axis shows a vertical axis chromatic aberration value (unit: μm) for each wavelength with respect to the center wavelength, and the vertical axis shows a normalized angle of view. As can be seen from the figure, the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within +/-5 mu m, which shows that the optical lens can excellently correct the chromatic aberration of the marginal field of view and the secondary spectrum of the whole image surface.

Please refer to table 5, which shows the corresponding optical characteristics of the above embodiments, including the effective focal length f, the total optical length TTL, the aperture FNO, the real image height IH, and the maximum field angle FOV of the optical lens, and the corresponding values of each conditional expression in the embodiments.

TABLE 5

In summary, the optical lens of the embodiments of the invention has the advantages of low chromatic dispersion, high relative illumination, high imaging quality and low cost by reasonably matching the lens shape and the focal power combination between the lenses.

In the description of the specification, reference to the description of "one embodiment," "some embodiments," "an example," "a specific example," or "some examples" or the like 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 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 embodiments only show several embodiments of the present invention, and the description is specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, various changes and modifications can be made 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 system comprising five lenses, in order from an object side to an image plane along an optical axis:

the first aspheric lens with negative focal power has a convex surface at the position close to the optical axis of the object side surface and a concave surface at the position close to the optical axis of the image side surface;

the object side surface and the image side surface of the spherical second lens with positive focal power are convex surfaces;

a diaphragm;

the object side surface and the image side surface of the spherical third lens are convex surfaces;

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

the fourth lens and the fifth lens are mutually glued to form a cemented lens;

The height D of the optical lens on the object side surface of the first lens corresponding to a half field angle of 30 degrees passing through the center of the diaphragm₃₀Height D of the object-side surface of the first lens corresponding to the maximum half field angle through the center of the diaphragm_θSatisfies the following conditions: d is more than 0.6₃₀/D_θ＜0.9。

2. An optical lens according to claim 1, wherein the total optical length TTL and the effective focal length f satisfy: TTL/f is more than 4.5 and less than 5.5.

3. The optical lens of claim 1, wherein the optical lens has a real image height IH corresponding to a half field angle of 30 ° in the optical lens₃₀True image height IH corresponding to maximum half field angle_θSatisfies the following conditions: IH of 0.65₃₀/IH_θ＜0.7。

4. An optical lens as claimed in claim 1, characterized in that the effective focal length f of the optical lens is the rise Sag of the object-side surface of the first lens₁Satisfies the following conditions: sag of 0.3₁/f＜0.35。

5. An optical lens according to claim 1, characterized in that the effective focal length f of the optical lens and the focal length f of the first lens are₁And a center thickness CT of the first lens₁Respectively satisfy: -1.9 < f₁/f＜-1.7；0.6≤CT₁/f≤0.65。

6. An optical lens according to claim 1, characterized in that the focal length f of the second lens₂Focal length f of the third lens₃Satisfies the following conditions: 1.0 < f₂/f₃＜1.2。

7. An optical lens according to claim 1, characterized in that the focal length f of the fourth lens₄With said fifth lensFocal length f₅Satisfies the following conditions: -0.85 < f₄/f₅＜-0.7。

8. An optical lens as recited in claim 1, wherein the second lens has a radius of curvature R at the image side surface₄And the object side curvature radius R of the third lens₅Satisfies the following conditions: -1.1. Ltoreq.R₄/R₅＜-1.0。

9. An optical lens system according to claim 1, wherein the third lens element has an object-side radius of curvature R5 and an image-side radius of curvature R6 that satisfy: -1.0 < R₅/R₆＜-0.3。

10. An optical lens according to claim 1, characterized in that the combined focal length f of the first and second lens is₁₂A combined focal length f with the fourth lens and the fifth lens₄₅Satisfies the following conditions: f is not less than 0.95₁₂/f₄₅＜1.2。