WO2024103957A1

WO2024103957A1 - Optical lens

Info

Publication number: WO2024103957A1
Application number: PCT/CN2023/119751
Authority: WO
Inventors: 牛钰澎; 张歆越; 王克民
Original assignee: 江西联创电子有限公司
Priority date: 2022-11-16
Filing date: 2023-09-19
Publication date: 2024-05-23
Also published as: CN115494624B; CN115494624A

Abstract

An optical lens, comprising, from an object side to an imaging surface along an optical axis, the following eight lenses in sequence: a first lens (L1) having negative focal power, the object side surface (S1) thereof being a convex surface, and the image side surface (S2) thereof being a concave surface; a second lens (L2) having negative focal power, the object side surface (S3) and the image side surface (S4) thereof being both concave surfaces; a third lens (L3) having focal power, the object side surface (S5) thereof being a convex surface, and the image side surface (S6) thereof being a concave surface; a fourth lens (L4) having positive focal power, the object side surface (S7) and the image side surface (S8) thereof both being convex surfaces; a stop (ST); a fifth lens (L5) having positive focal power, the object side surface (S9) and the image side surface (S10) thereof both being convex surfaces; a sixth lens (L6) having positive focal power, the object side surface (S11) and the image side surface (S12) thereof being both convex surfaces; a seventh lens (L7) having negative focal power, the object side surface (S13) and the image side surface (S14) thereof both being concave surfaces; and an eighth lens (L8) having positive focal power, the object side surface (S15) and the image side surface (S16) thereof being both convex surfaces. The effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 30<|f3/f|. The optical lens has the advantages of large field of view, large aperture, high definition and high imaging quality.

Description

Optical lens

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Chinese application No. 2022114330567, filed on November 16, 2022, the entire contents of which are incorporated herein by reference for all purposes.

Technical Field

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

Background technique

With the rapid development of advanced driver assistance systems (ADAS), automotive lenses have a wider range of applications and developments. These include driving recorders, automatic parking, front collision warning (FCW), lane departure warning (LDW), pedestrian detection warning (PCW), etc. Although the existing wide-angle automotive lenses can basically meet the basic needs of using large-field-of-view automotive lenses, there are still many defects, such as too small field of view or aperture and insufficient resolution.

Application Contents

In view of the above problems, the purpose of the present application is to propose an optical lens which has the advantages of a large field of view, a large aperture, high definition and high imaging quality.

To achieve the above purpose, the technical solution of this application is as follows:

An optical lens, with a total of eight lenses, along the optical axis from the object side to the imaging surface are:

The first lens has a negative optical power, and its object side surface is convex and its image side surface is concave;

The second lens has negative optical power, and both the object side surface and the image side surface are concave;

A third lens having optical power, whose object side surface is convex and whose image side surface is concave;

The fourth lens has positive refractive power, and both the object side surface and the image side surface are convex;

Aperture;

A fifth lens having positive refractive power, whose object-side surface and image-side surface are both convex;

The sixth lens has positive refractive power, and both the object side surface and the image side surface are convex;

The seventh lens element has negative optical power, and both the object side surface and the image side surface are concave;

The eighth lens has positive refractive power, and both the object side surface and the image side surface are convex;

The effective focal length f of the optical lens and the focal length _f3 of the third lens satisfy: 30<| _f3 /f|.

Preferably, the total optical length TTL and the effective focal length f of the optical lens satisfy: 7.5＜TTL/f＜9.5.

Preferably, the effective focal length f, the maximum field of view FOV and the real image height IH corresponding to the maximum field of view of the optical lens satisfy: 0.5＜(IH/2)/(f×tan(FOV/2))＜0.6.

Preferably, the effective focal length f of the optical lens and the focal length _f1 of the first lens satisfy: -3.0＜ _f1 /f＜0.

Preferably, the effective focal length f of the optical lens and the focal length _f8 of the eighth lens satisfy: 0＜ _f8 /f＜2.5.

Preferably, the combined focal length _ffront of the aperture front lens and the combined focal length _fback of the aperture rear lens of the optical lens satisfy: -1.8＜ _ffront / _fback ＜-1.0.

Preferably, the focal length _f6 of the sixth lens and the focal length _f7 of the seventh lens satisfy: -1.8＜ _f6 / _f7 ＜-1.3.

Preferably, the object-side surface curvature radius _R5 and the image-side surface curvature radius _R6 of the third lens satisfy: 0.5＜ _R5 / _R6 ＜1.6.

Preferably, the object-side sag height Sag ₁ and the clear semi-aperture d ₁ of the first lens and the image-side sag height Sag ₂ and the clear semi-aperture d ₂ of the first lens respectively satisfy: 0＜Sag ₁ /d ₁ ＜0.3, 0.6＜Sag ₂ /d ₂ ＜0.9.

Preferably, the total optical length TTL of the optical lens and the sum ΣCT of the center thicknesses of the first lens to the eighth lens along the optical axis respectively satisfy: 0.5＜ΣCT/TTL＜0.65.

Compared with the prior art, the beneficial effect of the present application is that the optical lens of the present application achieves the advantages of a large field of view, a large aperture, high definition and high imaging quality by reasonably matching the lens shape and optical focal length combination between each lens.

Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and/or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

FIG1 is a schematic diagram of the structure of an optical lens according to Example 1 of the present application;

FIG2 is a field curvature curve diagram of the optical lens in Example 1 of the present application;

FIG3 is a F-tanθ distortion curve diagram of the optical lens in Example 1 of the present application;

FIG4 is a relative illumination curve diagram of the optical lens in Example 1 of the present application;

FIG5 is a MTF curve diagram of the optical lens in Example 1 of the present application;

FIG6 is a graph showing an axial aberration of the optical lens in Example 1 of the present application;

FIG. 7 is a vertical axis chromatic aberration curve diagram of the optical lens in Example 1 of the present application;

FIG8 is a schematic structural diagram of an optical lens according to Example 2 of the present application;

FIG9 is a field curvature curve diagram of the optical lens in Example 2 of the present application;

FIG10 is a F-tanθ distortion curve diagram of the optical lens in Example 2 of the present application;

FIG11 is a relative illumination curve diagram of the optical lens in Example 2 of the present application;

FIG12 is a MTF curve diagram of the optical lens in Example 2 of the present application;

FIG13 is a graph showing an axial aberration of the optical lens in Example 2 of the present application;

FIG14 is a vertical axis chromatic aberration curve diagram of the optical lens in Example 2 of the present application;

FIG15 is a schematic diagram of the structure of an optical lens according to Example 3 of the present application;

FIG16 is a field curvature curve diagram of the optical lens in Example 3 of the present application;

FIG17 is a F-tanθ distortion curve diagram of the optical lens in Example 3 of the present application;

FIG18 is a relative illumination curve diagram of the optical lens in Example 3 of the present application;

FIG19 is a MTF curve diagram of the optical lens in Example 3 of the present application;

FIG20 is an axial aberration curve diagram of the optical lens in Example 3 of the present application;

FIG21 is a vertical axis chromatic aberration curve diagram of the optical lens in Example 3 of the present application;

FIG22 is a schematic diagram of the structure of an optical lens according to Example 4 of the present application;

FIG23 is a field curvature curve diagram of the optical lens in Example 4 of the present application;

FIG24 is a F-tanθ distortion curve diagram of the optical lens in Example 4 of the present application;

FIG25 is a relative illumination curve diagram of the optical lens in Example 4 of the present application;

FIG26 is a MTF curve diagram of the optical lens in Example 4 of the present application;

FIG27 is a graph showing an axial aberration of the optical lens in Example 4 of the present application;

FIG. 28 is a vertical axis chromatic aberration curve diagram of the optical lens in Example 4 of the present application.

The following specific implementation methods will further illustrate the present application in conjunction with the above-mentioned drawings.

Detailed ways

In order to better understand the present application, a more detailed description will be made of various aspects of the present application with reference to the accompanying drawings. It should be understood that these detailed descriptions are only descriptions of the embodiments of the present application, and are not intended to limit the scope of the present application in any way. Throughout the specification, the same reference numerals refer to the same elements. 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 of first, second, third, etc. are only used to distinguish one feature from another feature, and do not represent any limitation on the features. Therefore, without departing from the teaching of the present application, the first lens discussed below may also be referred to as the second lens or the third lens.

In the drawings, the thickness, size and shape of the lenses have been slightly exaggerated for ease of explanation. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are shown by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to the shapes of the spherical or aspherical surfaces shown in the drawings. The drawings are only examples and are not drawn strictly to scale.

In this article, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the position of the convex surface 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 position of the concave surface 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 of the lens, and the surface of each lens closest to the imaging plane is called the image side of the lens.

It should also be understood that the terms "comprises", "including", "having", "includes" and/or "comprising", when used in this specification, indicate the presence of the stated features, elements and/or components, but do not exclude the presence or addition of one or more other features, elements, components and/or combinations thereof. In addition, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire listed features rather than modifying the individual elements in the list. In addition, when describing embodiments of the present application, "may" is used to mean "one or more embodiments of the present application". And, the term "exemplary" is intended to refer to an example or illustration.

Unless otherwise defined, all terms (including technical terms and scientific terms) used in this article have the same meaning as commonly understood by ordinary technicians in the field to which this application belongs. It should also be understood that terms (such as terms defined in commonly used dictionaries) should be interpreted as having the same meaning as their meaning in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined in this article.

It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

The optical lens according to the embodiment of the present application includes, from the object side to the image side, a first lens, a second lens, a third lens, a fourth lens, Aperture, fifth lens, sixth lens, seventh lens and eighth lens.

In some embodiments, the first lens may have a negative optical power, which is beneficial to reduce the inclination angle of the incident light, thereby effectively sharing the large field of view of the object side. The image side surface of the first lens is convex, and the image side surface is concave, which is beneficial to collect as much large field of view light as possible into the rear optical lens.

In some embodiments, the second lens may have a negative focal length, which can share the negative focal length of the front end of the optical lens, thereby helping to avoid excessive light deflection caused by excessive concentration of the focal length of the first lens, and reducing the difficulty of correcting chromatic aberration of the optical lens. The object side and image side of the second lens are both concave, which is conducive to collecting the light incident after passing through the first lens, making the light transition smoothly, and improving the imaging quality of the optical lens.

In some embodiments, the object side of the third lens is convex and the image side is concave, which is conducive to converging light, allowing the diverged light to enter the rear smoothly, allowing the light to transition smoothly, and improving the imaging quality of the optical lens.

In some embodiments, the fourth lens may have positive focal length, which is beneficial to converge light while reducing the light deflection angle, so that the light transition is smooth. The object side and image side of the fourth lens are both convex, which is beneficial to reduce the influence of the fourth lens' own coma on the optical lens and improve the imaging quality of the optical lens.

In some embodiments, the fifth lens may have a positive focal length, which is beneficial for converging light while reducing the angle of light deflection, so that the light can transition smoothly. The object side and image side of the fifth lens are both convex, which can not only make the focus position of the light reflected by the object side of the fifth lens located behind the image side, effectively improving the design ghost of the optical lens, but also can reduce the influence of the fifth lens' own coma on the optical lens, and improve the imaging quality of the optical lens.

In some embodiments, the sixth lens may have a positive focal length, which is beneficial to converge light while reducing the light deflection angle, allowing the light to transition smoothly. The object side and image side of the sixth lens are both convex, which is beneficial to reduce the effect of the sixth lens' own coma on the optical lens and improve the imaging quality of the optical lens.

In some embodiments, the seventh lens may have a negative optical power, which is beneficial to increase the imaging area of the optical lens and improve the imaging quality of the optical lens. The object side and image side of the seventh lens are both concave, which can converge the central field of view light, thereby compressing the total length of the optical lens.

In some embodiments, the eighth lens may have a positive focal length, which is beneficial to converge light while reducing the light deflection angle, and controlling the incident angle of the principal light of the maximum field angle of the optical lens on the image plane within a range that matches the image sensor. The object side and image side of the eighth lens are both convex, which is beneficial to reduce the influence of the eighth lens' own coma on the optical lens and improve the imaging quality of the optical lens.

In some embodiments, an aperture for limiting the light beam may be provided between the fourth lens and the fifth lens. The aperture may be provided near the object side of the fifth lens, which can reduce the generation of optical lens ghosts and is beneficial for focusing the light entering the optical system and reducing the rear port diameter of the optical lens.

In some embodiments, the sixth lens and the seventh lens can be glued to form a glued lens, which can effectively correct the chromatic aberration of the optical lens, reduce the eccentricity sensitivity of the optical lens, balance the aberration of the optical lens, and improve the imaging quality of the optical lens; it can also reduce the assembly sensitivity of the optical lens, thereby reducing the difficulty of the processing technology of the optical lens and improving the assembly yield of the optical lens.

In some embodiments, the total optical length TTL and the effective focal length f of the optical lens satisfy: 7.5＜TTL/f＜9.5. Meeting the above range can effectively limit the length of the lens, which is conducive to miniaturization of the optical lens.

In some embodiments, the effective focal length f of the optical lens and the real image height IH corresponding to the maximum field angle satisfy: 1.8＜IH/f＜2.1. Meeting the above range can make the optical lens not only have a large image plane characteristic, but also have good imaging quality.

In some embodiments, the optical back focus BFL of the optical lens and the effective focal length f satisfy: 1.2＜BFL/f. Meeting the above range is conducive to achieving a balance between obtaining good imaging quality and easy assembly of the optical back focal length, ensuring the imaging quality of the optical lens while reducing the difficulty of the camera module assembly process.

In some embodiments, the effective focal length f, the maximum field of view FOV, and the real image height IH corresponding to the maximum field of view of the optical lens satisfy: 0.5＜(IH/2)/(f×tan(FOV/2))＜0.6. If the above range is met, it means that the optical distortion of the optical lens is well controlled, and the imaging quality of the optical lens is improved.

In some embodiments, the effective focal length f of the optical lens and the focal length _f1 of the first lens satisfy: -3.0＜ _f1 /f＜0. If the above range is met, the first lens can have an appropriate negative focal length, which is beneficial to expand the field of view of the optical lens.

In some embodiments, the effective focal length f of the optical lens and the focal length _f2 of the second lens satisfy: -2.2＜ _f2 /f＜0. When the above range is satisfied, the second lens can have an appropriate negative focal power, which can share the negative focal power of the first lens group of the optical lens, thereby facilitating the avoidance of excessive light deflection caused by excessive concentration of the focal length of the first lens, and reducing the difficulty of chromatic aberration correction of the optical lens.

In some embodiments, the effective focal length f of the optical lens and the focal length _f3 of the third lens satisfy: 30<| _f3 /f|. Meeting the above range can make the third lens have a larger optical power, which is conducive to smooth transition of light, balances various aberrations generated by the third lens itself, and improves the imaging quality of the optical lens.

In some embodiments, the effective focal length f of the optical lens and the focal length _f4 of the fourth lens satisfy: 0＜ _f4 /f＜3.0. Meeting the above range can make the fourth lens have appropriate positive focal power, which is conducive to smooth transition of light, correct various aberrations of the optical lens, and improve the imaging quality of the optical lens.

In some embodiments, the effective focal length f of the optical lens and the focal length _f5 of the fifth lens satisfy: 0＜ _f5 /f＜4.0. This allows the fifth lens to have an appropriate positive focal power, which is beneficial to the smooth transition of light, corrects various aberrations of the optical lens, and improves the imaging quality of the optical lens.

In some embodiments, the effective focal length f of the optical lens and the focal length _f6 of the sixth lens satisfy: 0＜ _f6 /f＜2.5. Meeting the above range can make the sixth lens have appropriate positive focal power, which is conducive to smooth transition of light, correcting the field curvature of the optical lens, and improving the imaging quality of the optical lens.

In some embodiments, the effective focal length f of the optical lens and the focal length _f7 of the seventh lens satisfy: -1.5＜ _f7 /f＜0. If the above range is satisfied, the seventh lens can have an appropriate negative focal power, which is beneficial to increase the imaging area of the optical lens, correct the field curvature of the optical lens, and improve the imaging quality of the optical lens.

In some embodiments, the effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: 0＜f8/f＜2.5. If the above range is met, the eighth lens can have an appropriate positive focal power, which is beneficial to correct the astigmatism and field curvature of the optical lens and improve the imaging quality of the optical lens.

In some embodiments, the combined focal length _ffront of the aperture front lens of the optical lens and the combined focal length _fback of the aperture rear lens satisfy: -1.8＜ _ffront / _fback ＜-1.0. Meeting the above range can make the combined focal length distribution of the aperture front and rear lenses similar, which helps to smoothly transition the light and improve the imaging quality of the optical lens.

In some embodiments, the focal length _f6 of the sixth lens and the focal length _f7 of the seventh lens satisfy: -1.8＜ _f6 / _f7 ＜-1.3. If the above range is met, the sixth lens and the seventh lens can have opposite and similar focal powers, which can effectively correct the chromatic aberration of the optical lens and improve the imaging quality of the optical lens.

In some embodiments, the radius of curvature _R5 of the object side surface of the third lens and the radius of curvature _R6 of the image side surface satisfy: 0.5＜ _R5 / _R6 ＜1.6. If the above range is met, the object side surface and the image side surface of the third lens can have similar surface shapes, which is beneficial to reduce the field curvature of the third lens and improve the imaging quality of the optical lens.

In some embodiments, the sag height Sag ₁ and the semi-aperture d ₁ of the object side of the first lens and the sag height Sag ₂ and the semi-aperture d ₂ of the image side of the first lens respectively satisfy: 0＜Sag ₁ /d ₁ ＜0.3, 0.6＜Sag ₂ /d ₂ ＜0.9. Meeting the above ranges can effectively constrain the surface shape of the off-axis field of view of the object side of the first lens, ensure that the incident angle of the light when incident on the imaging surface is small, thereby ensuring that the optical lens has a large relative illumination; it can effectively constrain the surface shape of the off-axis field of view of the image side of the first lens, ensure that the edge field light has a sufficient deflection angle when passing through the first lens, thereby ensuring that the optical lens has a small rear port diameter.

In some embodiments, the total optical length TTL of the optical lens and the sum of the center thicknesses of the first lens to the eighth lens along the optical axis ΣCT satisfy: 0.5＜ΣCT/TTL＜0.65. Meeting the above range can effectively reduce the total length of the optical lens, and is beneficial to the structural design and production process of the optical lens.

In order to make the system have better optical performance, multiple aspherical lenses are used in the lens, and the shape of each aspherical surface of the optical lens satisfies the following equation:

Among them, z is the distance between the surface and the vertex of the surface in the direction of the optical axis, h is the distance from the optical axis to the surface, c is the curvature of the surface vertex, K is the quadratic surface coefficient, A, B, C, D, E, and F are the second-order, fourth-order, sixth-order, eighth-order, tenth-order, and twelfth-order surface coefficients respectively.

The present application is further described below in multiple embodiments. In each embodiment, the thickness, radius of curvature, and material selection of each lens in the optical lens are different. For specific differences, please refer to the parameter table of each embodiment. The following embodiments are only preferred embodiments of the present application, but the embodiments of the present application are not limited to the following embodiments. Any other changes, substitutions, combinations, or simplifications that do not deviate from the innovative points of the present application should be regarded as equivalent replacement methods and are included in the protection scope of the present application.

Example 1

Please refer to FIG. 1 , which is a schematic diagram of the structure of the optical lens provided in Example 1 of the present application. The optical lens includes, in sequence from the object side to the imaging surface along the optical axis: a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, an aperture ST, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8 and a filter G1.

The first lens L1 has negative refractive power, its object side surface S1 is convex, and its image side surface S2 is concave;

The second lens L2 has negative refractive power, and its object-side surface S3 and image-side surface S4 are both concave;

The third lens L3 has positive refractive power, its object-side surface S5 is convex, and its image-side surface S6 is concave;

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

Aperture ST;

The fifth lens L5 has positive refractive power, and its object-side surface S9 and image-side surface S10 are both convex surfaces;

The sixth lens L6 has positive refractive power, and its object-side surface S11 and image-side surface S12 are both convex surfaces;

The seventh lens L7 has negative refractive power, and its object-side surface S13 and image-side surface S14 are both concave surfaces;

The eighth lens L8 has positive refractive power, and its object-side surface S15 and image-side surface S16 are both convex surfaces;

The sixth lens L6 and the seventh lens L7 may be cemented together to form a cemented lens;

The object side surface S17 and the image side surface S18 of the filter G1 are both planes;

The imaging surface S19 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 parameters of the aspherical lens of the optical lens in Example 1 are shown in Table 1-2.

Table 1-2

FIG2 shows the field curvature curve of Example 1. It can be seen from the figure that the field curvature of the meridional image plane and the sagittal image plane is controlled within ±0.02 mm, indicating that the optical lens can correct the field curvature very well.

FIG3 shows the F-tanθ distortion curve of Example 1. It can be seen from the figure that the F-tanθ distortion of the optical lens is controlled within ±50%, and the F-tanθ distortion curve is relatively smooth. The image compression in the large-angle area of the edge is relatively gentle, which effectively improves the clarity of the expanded image, indicating that the optical lens can correct the F-tanθ distortion well.

FIG. 4 shows a relative illumination curve of Example 1. It can be seen from the figure that the relative illumination value of the optical lens is still greater than 80% at the maximum half field angle, indicating that the optical lens has excellent relative illumination.

FIG5 shows an MTF (modulation transfer function) curve of Example 1. It can be seen from the figure that the MTF value of this embodiment is above 0.4 in the entire field of view. In the range of 0 to 160 lp/mm, the MTF curve decreases evenly and smoothly from the center to the edge of the field of view, and has good imaging quality and good detail resolution capability in both low-frequency and high-frequency conditions.

FIG6 shows the axial aberration curve of Example 1. It can be seen from the figure that the offset of the axial aberration is controlled within ±10 μm, indicating that the optical lens can correct the axial aberration well.

FIG7 shows the vertical chromatic aberration curve of Example 1. It can be seen from the figure that the vertical chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±4 μm, indicating that the optical lens can extremely well correct the chromatic aberration of the edge field of view and the secondary spectrum of the entire image plane.

Example 2

Please refer to FIG8 , which is a schematic diagram of the structure of the optical lens provided in Example 2 of the present application. The optical lens includes, in sequence from the object side to the imaging surface along the optical axis: a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, an aperture ST, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8 and a filter G1.

Aperture ST;

The seventh lens L7 has negative refractive power, and its object-side surface S13 and image-side surface S14 are both concave;

The sixth lens L6 and the seventh lens L7 may be cemented together to form a cemented lens.

The relevant parameters of each lens in the optical lens in Example 2 are shown in Table 2-1.

table 2-1

The surface parameters of the aspherical lens of the optical lens in Example 2 are shown in Table 2-2.

Table 2-2

FIG9 shows the field curvature curve of Example 2. It can be seen from the figure that the field curvature of the meridional image plane and the sagittal image plane is controlled within ±0.03 mm, indicating that the optical lens can correct the field curvature very well.

FIG10 shows the F-tanθ distortion curve of Example 2. It can be seen from the figure that the F-tanθ distortion of the optical lens is controlled within ±50%, and the F-tanθ distortion curve is relatively smooth. The image compression in the large-angle area of the edge is relatively gentle, which effectively improves the clarity of the expanded image, indicating that the optical lens can correct the F-tanθ distortion well.

FIG. 11 shows a relative illumination curve of Example 2. It can be seen from the figure that the relative illumination value of the optical lens is still greater than 80% at the maximum half field angle, indicating that the optical lens has excellent relative illumination.

FIG12 shows the MTF (Modulation Transfer Function) curve of Example 2. It can be seen from the figure that the MTF value of this embodiment is above 0.3 in the entire field of view. In the range of 0 to 160 lp/mm, the MTF curve decreases evenly and smoothly from the center to the edge of the field of view, and has good imaging quality and good detail resolution capability in both low-frequency and high-frequency conditions.

FIG. 13 shows the axial aberration curve of Example 2. It can be seen from the figure that the offset of the axial aberration is controlled within ±30 μm, indicating that the optical lens can correct the axial aberration well.

FIG14 shows the vertical chromatic aberration curve of Example 2. It can be seen from the figure that the vertical chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±2 μm, indicating that the optical lens can extremely well correct the chromatic aberration of the edge field of view and the secondary spectrum of the entire image plane.

Example 3

Please refer to FIG. 15 , which is a schematic diagram of the structure of the optical lens provided in Example 3 of the present application. The optical lens includes, in sequence from the object side to the imaging surface along the optical axis: a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, an aperture ST, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8 and a filter G1.

The third lens L3 has negative refractive power, its object-side surface S5 is convex, and its image-side surface S6 is concave;

Aperture ST;

The relevant parameters of each lens in the optical lens in Example 3 are shown in Table 3-1.

Table 3-1

The surface parameters of the aspherical lens of the optical lens in Example 3 are shown in Table 3-2.

Table 3-2

FIG16 shows the field curvature curve of Example 3. It can be seen from the figure that the field curvature of the meridional image plane and the sagittal image plane is controlled within ±0.02 mm, indicating that the optical lens can correct the field curvature very well.

FIG17 shows the F-tanθ distortion curve of Example 3. It can be seen from the figure that the F-tanθ distortion of the optical lens is controlled within ±50%, and the F-tanθ distortion curve is relatively smooth. The image compression in the large-angle area of the edge is relatively gentle, which effectively improves the clarity of the expanded image, indicating that the optical lens can correct the F-tanθ distortion well.

FIG. 18 shows the relative illumination curve of Example 3. It can be seen from the figure that the relative illumination value of the optical lens is still greater than 80% at the maximum half field angle, indicating that the optical lens has excellent relative illumination.

FIG19 shows the MTF (Modulation Transfer Function) curve of Example 3. It can be seen from the figure that the MTF value of this embodiment is above 0.5 in the entire field of view. In the range of 0 to 160 lp/mm, the MTF curve decreases evenly and smoothly from the center to the edge of the field of view, and has excellent imaging quality and excellent detail resolution capability in both low-frequency and high-frequency conditions.

FIG. 20 shows the axial aberration curve of Example 3. It can be seen from the figure that the offset of the axial aberration is controlled within ±10 μm, indicating that the optical lens can correct the axial aberration well.

FIG21 shows the vertical chromatic aberration curve of Example 3. It can be seen from the figure that the vertical chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±2 μm, indicating that the optical lens can extremely well correct the chromatic aberration of the edge field of view and the secondary spectrum of the entire image plane.

Example 4

Please refer to Figure 22, which is a schematic diagram of the structure of the optical lens provided in Example 4 of the present application. The optical lens includes, along the optical axis from the object side to the imaging surface, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, an aperture ST, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8 and a filter G1.

The fourth lens L4 has positive refractive power, and its object-side surface S7 and image-side surface S8 are both convex;

Aperture 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 parameters of the aspherical lens of the optical lens in Example 4 are shown in Table 4-2.

Table 4-2

FIG23 shows the field curvature curve of Example 4. It can be seen from the figure that the field curvature of the meridional image plane and the sagittal image plane is controlled within ±0.02 mm, indicating that the optical lens can correct the field curvature very well.

Figure 24 shows the F-tanθ distortion curve of Example 4. It can be seen from the figure that the F-tanθ distortion of the optical lens is controlled within ±50%, and the F-tanθ distortion curve is relatively smooth. The image compression in the large-angle area of the edge is relatively gentle, which effectively improves the clarity of the expanded image, indicating that the optical lens can correct the F-tanθ distortion well.

FIG. 25 shows the relative illumination curve of Example 4. It can be seen from the figure that the relative illumination value of the optical lens is still greater than 80% at the maximum half field of view angle, indicating that the optical lens has excellent relative illumination.

FIG26 shows the MTF (Modulation Transfer Function) curve of Example 4. It can be seen from the figure that the MTF value of this embodiment is above 0.5 in the entire field of view. In the range of 0 to 160 lp/mm, the MTF curve decreases evenly and smoothly from the center to the edge of the field of view, and has excellent imaging quality and excellent detail resolution capabilities in both low-frequency and high-frequency conditions.

FIG27 shows the axial aberration curve of Example 4. It can be seen from the figure that the offset of the axial aberration is controlled within ±5 μm, indicating that the optical lens can correct the axial aberration very well.

FIG28 shows the vertical chromatic aberration curve of Example 4. It can be seen from the figure that the vertical chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±2 μm, indicating that the optical lens can extremely well correct the chromatic aberration of the edge field of view and the secondary spectrum of the entire image plane.

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

table 5

In summary, the optical lens of the embodiment of the present application achieves the advantages of a large field of view, a large aperture, high definition and high imaging quality by reasonably matching the lens shapes and optical focal lengths of the lenses.

In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

An optical lens, comprising eight lenses, characterized in that the following are arranged in order from the object side to the imaging surface along the optical axis:

The first lens has a negative optical power, and its object side surface is convex and its image side surface is concave;

The second lens has negative optical power, and both the object side surface and the image side surface are concave;

A third lens having optical power, whose object side surface is convex and whose image side surface is concave;

The fourth lens has positive refractive power, and both the object side surface and the image side surface are convex;

Aperture;

A fifth lens having positive refractive power, whose object-side surface and image-side surface are both convex;

The sixth lens has positive refractive power, and both the object side surface and the image side surface are convex;

The seventh lens element has negative optical power, and both the object side surface and the image side surface are concave;

The eighth lens has positive refractive power, and both the object side surface and the image side surface are convex;

The effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 30＜|f3/f|.
The optical lens according to claim 1 is characterized in that the total optical length TTL and the effective focal length f of the optical lens satisfy: 7.5＜TTL/f＜9.5.
The optical lens according to claim 1 is characterized in that the effective focal length f, the maximum field of view FOV and the real image height IH corresponding to the maximum field of view of the optical lens satisfy: 0.5＜(IH/2)/(f×tan(FOV/2))＜0.6.
The optical lens according to claim 1 is characterized in that the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -3.0＜f1/f＜0.
The optical lens according to claim 1 is characterized in that the effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: 0＜f8/f＜2.5.
The optical lens according to claim 1 is characterized in that the combined focal length ffront of the aperture front lens and the combined focal length fback of the aperture rear lens of the optical lens satisfy: -1.8＜ffront/fback＜-1.0.
The optical lens according to claim 1, characterized in that the focal length f6 of the sixth lens and the focal length f7 of the seventh lens satisfy: -1.8＜f6/f7＜-1.3.
The optical lens according to claim 1, characterized in that the object side curvature radius R5 and the image side curvature radius R6 of the third lens satisfy: 0.5＜R5/R6＜1.6.
The optical lens according to claim 1 is characterized in that the object side sag height Sag1 and the clear semi-aperture d1 of the first lens and the image side sag height Sag2 and the clear semi-aperture d2 of the first lens respectively satisfy: 0＜Sag1/d1＜0.3, 0.6＜Sag2/d2＜0.9.
The optical lens according to claim 1 is characterized in that the total optical length TTL of the optical lens and the sum ΣCT of the center thicknesses of the first lens to the eighth lens along the optical axis respectively satisfy: 0.5＜ΣCT/TTL＜0.65.