CN115826195A

CN115826195A - Optical lens

Info

Publication number: CN115826195A
Application number: CN202211541957.8A
Authority: CN
Inventors: 凌兵兵; 鲍宇旻
Original assignee: Jiangxi Lianchuang Electronic Co Ltd
Current assignee: Jiangxi Lianchuang Electronic Co Ltd
Priority date: 2022-12-03
Filing date: 2022-12-03
Publication date: 2023-03-21

Abstract

The invention provides an optical lens, which comprises eight lenses, and is characterized in that the optical lens sequentially comprises the following components from an object side to an imaging surface along an optical axis: a first lens having a negative optical power, both the object-side surface and the image-side surface of which are concave; the second lens with negative focal power, the object side surface of the second lens is a concave surface, and the image side surface of the second lens is a convex surface; a third lens having a positive refractive power, both the object-side surface and the image-side surface of the third lens being convex; a diaphragm; a fourth lens having a positive refractive power, both the object-side surface and the image-side surface of the fourth lens being convex; a fifth lens element having a positive refractive power, the object-side surface and the image-side surface of the fifth lens element being convex; a sixth lens element having a negative refractive power, the object-side surface of which is concave; a seventh lens element with negative refractive power having a concave object-side surface and a convex image-side surface; the object side surface of the eighth lens with positive focal power is a convex surface, and the image side surface of the eighth lens is a concave surface.

Description

Optical lens

Technical Field

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

Background

With the development of automobile intellectualization, the assistant driving system of the vehicle is gradually improved, the vehicle-mounted lens is used as one of main tools for the assistant driving system to acquire external information, and the imaging quality of the vehicle-mounted lens directly influences the performance of the assistant driving system.

In order to accurately acquire external information, the onboard lens needs to be matched with a chip with a large size and a high resolution, and therefore the onboard lens needs to have a high resolution capability. In addition, in view of safety, the vehicle-mounted lens further needs to have high stability to adapt to various severe environments, and the problems that the imaging performance of the vehicle-mounted lens is reduced when the vehicle-mounted lens is used in different environments and the like are avoided.

Disclosure of Invention

In view of the above problems, an object of the present invention is to provide an optical lens having advantages of a large image plane, a large field of view, a large aperture, and miniaturization.

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

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

a first lens having a negative optical power, both the object-side surface and the image-side surface of which are concave;

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

a third lens having a positive refractive power, both the object-side surface and the image-side surface of the third lens being convex;

a diaphragm;

a fourth lens having a positive refractive power, both the object-side surface and the image-side surface of the fourth lens being convex;

a fifth lens element having a positive refractive power, the object-side surface and the image-side surface of the fifth lens element being convex;

a sixth lens element having a negative refractive power, the object-side surface of which is concave;

a seventh lens element with negative refractive power having a concave object-side surface and a convex image-side surface;

the object side surface of the eighth lens with positive focal power is a convex surface, and the image side surface of the eighth lens is a concave surface.

Preferably, the total optical length TTL and the effective focal length f of the optical lens satisfy: TTL/f is less than 5.0.

Preferably, the effective focal length f of the optical lens and the real image height IH corresponding to the maximum field angle satisfy: IH/f is more than 1.6.

Preferably, the optical back focus BFL and the effective focal length f of the optical lens satisfy: BFL/f is more than 0.5.

Preferably, the entrance pupil diameter EPD of the optical lens and the real image height IH corresponding to the maximum field angle satisfy: IH/EPD is more than 2.7 and less than 2.9.

Preferably, the effective focal length f, the maximum field angle FOV and the real image height IH corresponding to the maximum field angle of the optical lens satisfy: 0.5 < (IH/2)/(f × Tan (FOV/2)) < 0.7.

Preferably, theAn effective focal length f of the optical lens and a combined focal length f of the first lens to the third lens ₁₃ Satisfies the following conditions: 5.0 < | f ₁₃ /f|。

Preferably, the effective focal length f of the optical lens and the combined focal length f of the fourth lens to the eighth lens are set to be equal to each other ₄₈ Satisfies the following conditions: f is more than 0 ₄₈ /f＜2.0。

Preferably, the maximum field angle FOV of the optical lens, the real image height IH corresponding to the maximum field angle, and the object-side light-passing aperture D of the first lens ₁ Satisfies the following conditions: d is more than 0.6 ₁ /IH/Tan(FOV/2)＜0.8。

Preferably, the total optical length TTL of the optical lens and the total sum Σ CT of the central thicknesses of the first lens element to the seventh lens element along the optical axis satisfy: 0.6 <. Sigma CT/TTL < 0.8.

Compared with the prior art, the invention has the beneficial effects that: by reasonably matching the combination of the lens shape and the focal power among the lenses, the advantages of large image surface, large field of view, large aperture and miniaturization are realized.

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.

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 the F-Tan θ distortion of the optical lens in embodiment 1 of the present invention.

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

Fig. 5 is a MTF graph of the optical lens in embodiment 1 of the present invention.

Fig. 6 is a graph illustrating axial aberration of the optical lens system according to embodiment 1 of the present invention.

Fig. 7 is a vertical axis chromatic aberration diagram of the 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 field curvature graph of the optical lens in embodiment 2 of the present invention.

Fig. 10 is a graph showing the F-Tan θ distortion of the optical lens in embodiment 2 of the present invention.

Fig. 11 is a graph showing a relative illuminance of the optical lens in embodiment 2 of the present invention.

Fig. 12 is a MTF graph of the optical lens in embodiment 2 of the present invention.

Fig. 13 is a graph illustrating axial aberration of the optical lens in embodiment 2 of the present invention.

Fig. 14 is a vertical axis chromatic aberration diagram of the 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 field curvature graph of the optical lens in embodiment 3 of the present invention.

Fig. 17 is a graph showing the F-Tan θ distortion of the optical lens in embodiment 3 of the present invention.

Fig. 18 is a graph showing a relative illuminance of the optical lens in embodiment 3 of the present invention.

Fig. 19 is a MTF graph of the optical lens in embodiment 3 of the present invention.

Fig. 20 is a graph showing axial aberration of the optical lens in embodiment 3 of the present invention.

Fig. 21 is a vertical axis chromatic aberration diagram of the 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 curvature of field graph of the optical lens in embodiment 4 of the present invention.

Fig. 24 is a graph showing the F-Tan θ distortion of the 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 the optical lens in embodiment 4 of the present invention.

Fig. 27 is a graph showing axial aberration of the optical lens in 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.

Detailed Description

For a better understanding of the present invention, various aspects of the present invention will be described in more detail with reference to the accompanying drawings. It should be understood that the detailed description is only illustrative of the embodiments of the invention and does not limit the scope of the invention 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 only used 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 a list of listed features, 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 invention" when describing embodiments of the invention. 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 invention 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 may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.

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

In some embodiments, the first lens may have a negative power, which is beneficial for reducing the inclination angle of the incident light, thereby achieving effective sharing of a large field of view of the object. The object side surface and the image side surface of the first lens are both concave surfaces, so that the effective working caliber of the first lens can be reduced, and overlarge caliber of a lens behind the optical lens caused by excessive divergence of light rays can be avoided

In some embodiments, the second lens element may have a negative focal power, and the negative focal power of the front end of the optical lens element can be shared, so that the optical lens element is beneficial to avoiding the excessive light deflection caused by the over-concentration of the focal power of the first lens element, and the difficulty in correcting chromatic aberration of the optical lens element is reduced. The object side surface of the second lens is a concave surface, and the image side surface of the second lens is a convex surface, so that light rays emitted after passing through the first lens can be collected, the light ray trend is in stable transition, and the imaging quality of the optical lens is improved.

In some embodiments, the third lens element may have a positive focal power, which is advantageous for converging light rays and reducing the deflection angle of the light rays, so that the light rays are smoothly transitioned. The object side surface and the image side surface of the third lens are convex surfaces, so that coma aberration 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 focal power, which is beneficial for converging light rays and reducing the deflection angle of the light rays, so that the light rays are in smooth transition. The object side surface and the image side surface of the fourth lens are convex surfaces, so that coma generated by the fourth lens can be reduced, the energy of ghost image projection generated by reflection in a central area on an image surface can be reduced, and the imaging quality of the optical lens is improved.

In some embodiments, the fifth lens element may have a positive focal power, which is beneficial for converging light rays and reducing the deflection angle of the light rays, so that the light rays are in smooth transition.

In some embodiments, the sixth lens element may have a negative refractive power, which is beneficial to correct chromatic aberration of the optical lens and improve the imaging quality of the optical lens.

In some embodiments, the seventh lens element may have a negative focal power, which is beneficial to increasing an imaging area of the optical lens and improving an imaging quality of the optical lens. The object side surface of the seventh lens is a concave surface, the image side surface of the seventh lens is a convex surface, edge light rays can be converged, more light rays are transmitted to the rear-end lens, the relative illumination of the optical lens is improved, the field curvature generated by the seventh lens can be reduced, and the imaging quality of the optical lens is improved.

In some embodiments, the eighth lens element may have a positive focal power, which is beneficial for converging light rays and reducing the deflection angle of the light rays, so that the light rays are in smooth transition. The object side surface of the eighth lens is a convex surface, the image side surface of the eighth lens is a concave surface, the angle of the marginal view field incident on the imaging surface can be suppressed, more light beams are effectively transmitted to the imaging surface, and the relative illumination of the optical lens is improved.

In some embodiments, the fifth lens and the sixth lens can be cemented to form a cemented lens, which can effectively correct chromatic aberration of the optical lens, reduce eccentricity sensitivity of the optical lens, balance aberration of the optical lens, and improve imaging quality of the optical lens; 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, a diaphragm for limiting the light beam may be disposed between the third lens and the fourth lens, and the diaphragm may be disposed near an image side surface of the third lens, so as to reduce generation of ghost images of the optical lens, and facilitate converging light entering the optical system and reduce a rear end aperture of the optical lens.

In some embodiments, the aperture ratio FNO of the optical lens satisfies: FNO is less than or equal to 1.64. The range is satisfied, the large aperture characteristic is favorably realized, and the image definition can be ensured in a low-light environment or at night.

In some embodiments, the maximum field angle FOV of the optical lens satisfies: 100 ° < FOV. The wide-angle detection method has the advantages that the wide-angle characteristic is favorably realized, more scene information can be acquired, and the requirement of large-range detection is met.

In some embodiments, the incident angle CRA of the maximum field angle chief ray of the optical lens on the image plane satisfies: 10 DEG < CRA < 16 deg. Satisfying the above range, the allowable error value between the CRA of the optical lens and the CRA of the chip photosensitive element can be made larger, and the adaptability of the optical lens to the image sensor can be improved.

In some embodiments, the total optical length TTL and the effective focal length f of the optical lens satisfy: TTL/f is less than 5.0. The optical lens can effectively limit the length of the lens and realize the miniaturization of the optical lens.

In some embodiments, the real image height IH at which the effective focal length f of the optical lens corresponds to the maximum field angle satisfies: IH/f is more than 1.6. The optical lens satisfies the above range, and not only has large image plane characteristics, but also has good imaging quality.

In some embodiments, the optical back focus BFL and the effective focal length f of the optical lens satisfy: BFL/f is more than 0.5. The method meets the range, is favorable for obtaining balance between good imaging quality and optical back focal length easy to assemble, and reduces the difficulty of the camera module assembly process while ensuring the imaging quality of the optical lens.

In some embodiments, the real image height IH of the optical lens corresponding to the maximum field angle and the entrance pupil diameter EPD satisfy: IH/EPD is more than 2.7 and less than 2.9. The width of the light ray bundle entering the optical lens can be increased, so that the brightness of the optical lens at the image surface is improved, and the dark corner is avoided.

In some embodiments, the incident angle CRA of the maximum field angle FOV and the maximum field angle chief ray of the optical lens on the image plane satisfies: 3.0 < (FOV/2)/CRA < 5.0. The wide-field optical lens has the advantages that the wide-field optical lens can realize large field of view, incident light can enter the image sensor at a proper angle, the light sensitivity of the image sensor is improved, and the imaging quality of the optical lens is improved.

In some embodiments, the effective focal length f, the maximum field angle FOV, and the true image height IH corresponding to the maximum field angle of the optical lens satisfy: 0.5 < (IH/2)/(f × Tan (FOV/2)) < 0.7. The method meets the range, is favorable for controlling the ideal image height to be close to the actual image height, and realizes small distortion.

In some embodiments, the effective focal length f of the optical lens and the focal length f of the first lens are different ₁ Satisfies the following conditions: -1.5 < f ₁ The/f is less than 0. Satisfy above-mentioned scope, can make first lens have appropriate negative focal power, be favorable to incident light refraction angle change comparatively relaxes, avoid refraction change too strong and produce too much aberration, help more light to get into rear optical system simultaneously, increase illuminance and promote optical lens's imaging quality.

In some embodiments, the effective focal length f of the optical lens and the focal length f of the second lens ₂ Satisfies the following conditions: -6.0 < f ₂ The/f is less than 0. The second lens has proper negative focal power and can share the negative focal power of the front end of the optical lens, so that the optical lens is favorable for avoiding overlarge light deflection caused by over concentration of the focal power of the first lens, and the optical lens is reducedDifficulty in correcting chromatic aberration.

In some embodiments, the effective focal length f of the optical lens and the focal length f of the third lens are ₃ Satisfies the following conditions: f is more than 0 ₃ The/f is less than 1.5. Satisfying above-mentioned scope, can making the third lens have appropriate positive focal power, be favorable to assembling light and reduce light deflection angle simultaneously, let the light trend smooth transition, promote optical lens's the formation of image quality.

In some embodiments, the effective focal length f of the optical lens and the focal length f of the fourth lens are ₄ Satisfies the following conditions: f is more than 0 ₄ The/f is less than 5.0. Satisfying above-mentioned scope, can making the fourth lens have appropriate positive focal power, be favorable to gathering reducing light deflection angle when light, let the light trend smooth transition, promote optical lens's the formation of image quality.

In some embodiments, the effective focal length f of the optical lens and the focal length f of the fifth lens ₅ Satisfies the following conditions: f is more than 0 ₅ The/f is less than 1.0. Satisfying above-mentioned scope, can making the fifth lens have appropriate positive focal power, be favorable to gathering light and reducing light deflection angle simultaneously, let the light trend smooth transition, promote optical lens's the formation of image quality.

In some embodiments, the effective focal length f of the optical lens and the focal length f of the sixth lens element ₆ Satisfies the following conditions: -1.5 < f ₆ The/f is less than 0. The sixth lens has appropriate negative focal power, so that chromatic aberration of the optical lens can be corrected, and imaging quality of the optical lens is improved.

In some embodiments, the effective focal length f of the optical lens and the focal length f of the seventh lens ₇ Satisfies the following conditions: -4.0 < f ₇ The/f is less than 0. The seventh lens has appropriate negative focal power, so that the imaging area of the optical lens can be increased, and the imaging quality of the optical lens can be improved.

In some embodiments, the effective focal length f of the optical lens and the focal length f of the eighth lens element ₈ Satisfies the following conditions: f is more than 0 ₈ The/f is less than 3.0. The negative focal power of the eighth lens is appropriate, so that the light rays can be converged, the deflection angle of the light rays is reduced, and the light rays are in smooth transition.

In some embodiments, the effective focal length f of the optical lens and the combined focal length f of the first lens to the third lens ₁₃ Satisfies the following conditions: 5.0 < | f ₁₃ And/f |. Satisfy above-mentioned scope, through the focus of rational distribution first lens to third lens for the light trend that gets into the optical lens rear end is steady, is favorable to reducing the correction degree of difficulty of all kinds of aberrations, promotes optical lens's image quality.

In some embodiments, the effective focal length f of the optical lens and the combined focal length f of the fourth lens to the eighth lens ₄₈ Satisfies the following conditions: f is more than 0 ₄₈ The/f is less than 2.0. Satisfy above-mentioned scope, through the focus of rational distribution fourth lens to eighth lens, be favorable to balancing all kinds of aberrations, promote optical lens's imaging quality.

In some embodiments, the focal length f of the fifth lens of the optical lens ₅ Focal length f of the sixth lens ₆ Satisfies the following conditions: -0.50 < (f) ₅ +f ₆ ) The/f is less than 0. The chromatic aberration correction method meets the range, is favorable for correcting chromatic aberration of the optical lens, and improves imaging quality of the optical lens.

In some embodiments, the maximum field angle FOV of the optical lens, the real image height IH corresponding to the maximum field angle, and the first lens object-side clear aperture D ₁ Satisfies the following conditions: d is more than 0.6 ₁ the/IH/Tan (FOV/2) < 0.8. The optical lens has a large field angle and a large image plane, and the front port diameter is small, so that the optical lens is miniaturized.

In some embodiments, the total optical length TTL of the optical lens and the sum Σ CT of the central thicknesses of the first lens to the seventh lens along the optical axis, respectively, satisfy: 0.6 <. Sigma CT/TTL < 0.8. The optical lens structure meets the range, can effectively compress the total length of the optical lens, and is beneficial to the structural design and the production process of the optical lens.

In order to make the system have better optical performance, a plurality of aspheric lenses are adopted in the lens, and the surface 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 optical axis direction, 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, F are the coefficients of the second order, the fourth order, the sixth order, the eighth order, the tenth order and the twelfth order curved surface respectively.

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

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 third lens L3, a stop ST, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, an optical filter G1, and a cover glass G2.

The first lens L1 has negative focal power, and both the object side surface S1 and the image side surface S2 are concave surfaces;

the second lens L2 has negative focal power, the object side surface S3 is a concave surface, and the image side surface S4 is a convex surface;

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 positive focal power, and both the object side surface S9 and the image side surface S10 are convex surfaces;

the sixth lens element L6 has a negative focal power, and has a concave object-side surface S11 and a convex image-side surface S12;

the seventh lens element L7 has negative power, and has a concave object-side surface S13 and a convex image-side surface S14;

the eighth lens element L8 has positive refractive power, and has a convex object-side surface S15 and a concave image-side surface S16;

the optical filter G1 is provided with a plane object side surface S17 and a plane image side surface S18;

the protective glass G2, the object side surface S19 and the image side surface S20 are both flat surfaces;

the imaging surface S21 is a plane;

the fifth lens L5 and the sixth lens L6 may be cemented to constitute a cemented lens.

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

Fig. 2 shows a field curvature graph of example 1, 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 ± 0.09mm, which indicates that the optical lens can correct the field curvature well.

Fig. 3 shows a graph of F-Tan θ distortion of example 1, in which F-Tan θ distortion at different image heights on an image forming plane is shown for light rays of different wavelengths, the abscissa shows the F-Tan θ distortion (unit:%), and the ordinate shows the half field angle (unit:%). As can be seen from the figure, the F-Tan theta distortion of the optical lens is controlled within +/-40%, which shows that the optical lens can correct the F-Tan theta distortion well.

Fig. 4 shows a graph of relative illuminance for example 1, which represents relative illuminance values for 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 at the maximum half field angle is still greater than 70%, indicating that the optical lens has good relative illuminance.

Fig. 5 shows a Modulation Transfer Function (MTF) graph of embodiment 1, which represents the degree of modulation of lens imaging representing 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 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 reduced in the process from the center to the edge field of view, and the image quality and the detail resolution capability are better under the conditions of low frequency and high frequency.

Fig. 6 shows an axial aberration graph 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: μm) and the vertical axis representing the normalized pupil radius. As can be seen from the figure, the amount of shift of the axial aberration is controlled within ± 20 μm, indicating that the optical lens can correct the axial aberration well.

Fig. 7 is a vertical axis chromatic aberration graph 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), and 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 excellently correct the chromatic aberration of the marginal field of view and the secondary spectrum of the whole image surface.

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 third lens L3, a stop ST, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, an optical filter G1, and a cover glass G2.

The first lens L1 has negative focal power, and the object side surface S1 and the image side surface S2 are both concave surfaces;

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 sixth lens L6 has negative refractive power, and both the object-side surface S11 and the image-side surface S12 are concave;

the imaging surface S21 is a plane;

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

TABLE 2-1

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

Tables 2 to 2

Fig. 9 shows a field curvature graph 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 ± 0.08mm, which indicates that the optical lens can correct the field curvature well.

Fig. 10 shows a F-Tan θ distortion graph of example 2, 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 +/-40%, which shows that the optical lens can correct the F-Tan theta distortion well.

Fig. 11 shows a relative illuminance graph of example 2, which represents relative illuminance values at different angles of field of view on an imaging plane, with the horizontal axis representing a half field angle (unit: °) and the vertical axis representing relative illuminance (unit:%). As can be seen from the figure, the relative illuminance value of the optical lens at the maximum half field angle is still greater than 70%, indicating that the optical lens has good relative illuminance.

Fig. 12 shows a Modulation Transfer Function (MTF) graph of embodiment 2, which represents the lens imaging modulation degree representing 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 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 reduced in the process from the center to the edge field of view, and the image quality and the detail resolution capability are better under the conditions of low frequency and high frequency.

Fig. 13 shows an axial aberration graph 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: μm) and the vertical axis representing the normalized pupil radius. As can be seen from the figure, the amount of shift of the axial aberration is controlled within ± 15 μm, indicating that the optical lens can correct the axial aberration well.

Fig. 14 is a vertical axis chromatic aberration graph 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), and 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.

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 third lens L3, a stop ST, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, an optical filter G1, and a cover glass G2.

a diaphragm ST;

a cover glass G2 whose object-side surface S19 and image-side surface S20 are both flat surfaces;

the imaging surface S21 is a plane;

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

Fig. 16 shows a field curvature graph 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 +/-0.05 mm, which shows that the optical lens can excellently correct the field curvature.

Fig. 17 shows a F-Tan θ distortion graph of example 3, 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 +/-40%, which shows that the optical lens can correct the F-Tan theta distortion well.

Fig. 18 shows a relative illuminance graph 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 illuminance value of the optical lens at the maximum half field angle is still greater than 70%, indicating that the optical lens has good relative illuminance.

Fig. 19 shows a Modulation Transfer Function (MTF) graph of example 3, which represents the degree of modulation of lens imaging representing 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 0.4 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 are good in both the low frequency and the high frequency.

Fig. 20 shows an axial aberration graph 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: μm) and the vertical axis representing the normalized pupil radius. As can be seen from the figure, the amount of shift of the axial aberration is controlled within ± 10 μm, indicating that the optical lens can excellently correct the axial aberration.

Fig. 21 is a vertical axis chromatic aberration graph 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), and in which 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 excellently correct the chromatic aberration of the marginal field of view and the secondary spectrum of the whole image surface.

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 third lens L3, a stop ST, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, an optical filter G1, and a cover glass G2.

a diaphragm ST;

the sixth lens element L6 has negative focal power, and has a concave object-side surface S11 and a convex image-side surface S12;

the imaging surface S21 is a plane;

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 graph 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 +/-0.04 mm, which shows that the optical lens can excellently correct the field curvature.

Fig. 24 is a graph showing the F-Tan θ distortion of example 4 at different image heights on the image forming plane for light rays of different wavelengths, in which the horizontal axis shows the F-Tan θ distortion (unit:%) and the vertical axis shows the half field angle (unit: °). As can be seen from the figure, the F-Tan theta distortion of the optical lens is controlled within +/-40%, which shows that the optical lens can correct the F-Tan theta distortion well.

Fig. 25 shows a relative illuminance graph 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 at the maximum half field angle is still greater than 70%, indicating that the optical lens has good relative illuminance.

Fig. 26 shows a Modulation Transfer Function (MTF) graph of example 4, which represents the degree of modulation of lens imaging representing 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 0.4 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 are good in both the low frequency and the high frequency.

Fig. 27 shows an axial aberration graph 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: μm) and the vertical axis representing the normalized pupil radius. As can be seen from the figure, the amount of shift of the axial aberration is controlled within ± 10 μm, indicating that the optical lens can correct the axial aberration well.

Fig. 28 is a vertical axis chromatic aberration graph 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), and in which 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 are controlled to ± 4 μm to refer to table 5, which is the optical characteristics corresponding to the above embodiments, including the effective focal length f, the total optical length TTL, the aperture coefficient FNO, the real image height IH, the field angle FOV, and the values corresponding to each conditional expression in the embodiments.

TABLE 5

In summary, the optical lens of the embodiment of the invention realizes the advantages of large image plane, large field of view, large aperture and miniaturization by reasonably matching the combination of the lens shape and the focal power among the lenses.

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

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is specific and detailed, but not to be understood as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

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

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

a diaphragm;

2. An optical lens according to claim 1, wherein the total optical length TTL and the effective focal length f satisfy: TTL/f is less than 5.0.

3. The optical lens according to claim 1, wherein a real image height IH of the optical lens corresponding to an effective focal length f and a maximum field angle satisfies: IH/f is more than 1.6.

4. An optical lens according to claim 1, characterized in that the optical back focus BFL and the effective focal length f of the optical lens satisfy: BFL/f is more than 0.5.

5. The optical lens of claim 1, wherein an entrance pupil diameter EPD of the optical lens satisfies a real image height IH corresponding to a maximum field angle: IH/EPD is more than 2.7 and less than 2.9.

6. The optical lens according to claim 1, wherein the effective focal length f, the maximum field angle FOV and the real image height IH corresponding to the maximum field angle of the optical lens satisfy: 0.5 < (IH/2)/(f × Tan (FOV/2)) < 0.7.

7. An optical lens according to claim 1, characterized in that the effective focal length f of the optical lens and the combined focal length f of the first to third lenses ₁₃ Satisfies the following conditions: 5.0 < | f ₁₃ /f|。

8. An optical lens according to claim 1, characterized in that the effective focal length f of the optical lens and the combined focal length f of the fourth to eighth lenses ₄₈ Satisfies the following conditions: 0 < (R) >f ₄₈ /f＜2.0。

9. The optical lens according to claim 1, wherein the maximum field angle FOV, the real image height IH corresponding to the maximum field angle and the object-side aperture D of the first lens are the same as each other ₁ Satisfies the following conditions: d is more than 0.6 ₁ /IH/Tan(FOV/2)＜0.8。

10. An optical lens according to claim 1, wherein an optical total length TTL of the optical lens and a sum Σ CT of central thicknesses of the first lens to the seventh lens along the optical axis, respectively, satisfy: 0.6 <. Sigma CT/TTL < 0.8.