CN115951483A

CN115951483A - Optical lens

Info

Publication number: CN115951483A
Application number: CN202310245588.6A
Authority: CN
Inventors: 牛钰澎; 陈伟建; 王克民
Original assignee: Jiangxi Lianchuang Electronic Co Ltd
Current assignee: Jiangxi Lianchuang Electronic Co Ltd
Priority date: 2023-03-15
Filing date: 2023-03-15
Publication date: 2023-04-11
Anticipated expiration: 2043-03-15
Also published as: CN115951483B

Abstract

The invention provides an optical lens, which comprises seven lenses in total, wherein the seven lenses are sequentially arranged from an object side to an imaging surface along an optical axis: a first lens having a negative refractive power, an image-side surface of which is concave; the second lens with positive focal power has a convex object-side surface and a concave image-side surface; a third lens having a positive optical power; 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 negative refractive power, both the object-side surface and the image-side surface of which are concave surfaces; a sixth lens element with negative refractive power having a concave object-side surface and a convex image-side surface; a seventh lens having positive refractive power, an object-side surface of which is convex; the effective focal length f of the optical lens meets the real image height IH corresponding to the maximum field angle FOV and the maximum field angle: 85 DEG < f × FOV/IH < 120 deg.

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 driving assistance function of the vehicle is gradually enhanced, wherein the visual information collection is a core tool. With the increase of the automatic driving level, the requirements on the vehicle-mounted camera are gradually increased, especially for the front camera. The front camera can enhance the active safety and driver assistance functions, such as Automatic Emergency Braking (AEB), adaptive Cruise Control (ACC), lane Keeping Assist System (LKAS), traffic Jam Assist (TJA), and the like, and has the disadvantages of a large number of lenses, an excessively long optical total length, and the like while meeting the advantages of high resolution, a large field angle, good environmental adaptability, and the like, and is not beneficial to the miniaturization of an electronic system.

Disclosure of Invention

In view of the above problems, it is an object of the present invention to provide an optical lens capable of solving one or more of the above problems.

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

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

the image side surface of the first lens is a concave surface;

a second lens having a positive refractive power, the object-side surface of which is convex and the image-side surface of which is concave;

a third lens having positive optical power;

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 negative refractive power, both the object-side surface and the image-side surface of the fifth lens element being concave;

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

a seventh lens having a positive refractive power, an object-side surface of which is convex;

the effective focal length f of the optical lens meets the real image height IH corresponding to the maximum field angle FOV and the maximum field angle: 85 DEG < f × FOV/IH < 120 deg.

Further, the total optical length TTL and the effective focal length f of the optical lens satisfy: TTL/f is more than 7.0 and less than 9.0.

Further, the maximum field angle FOV and the aperture value FNO of the optical lens satisfy: 80 < FOV/FNO < 110.

Further, an effective focal length f of the optical lens and a focal length f of the first lens ₁ Satisfies the following conditions: -3.5 < f ₁ /f＜0。

Further, an effective focal length f of the optical lens and a focal length f of the fourth lens ₄ Satisfies the following conditions: f is more than 0 ₄ /f＜1.5。

Further, an effective focal length f of the optical lens and a focal length f of the seventh lens ₇ Satisfies the following conditions: f is more than 0 ₇ /f＜2.5。

Further, an 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: -3.0 < f ₁₃ /f＜-2.0。

Further, an effective focal length f of the optical lens and a combined focal length f of the fourth lens to the seventh lens ₄₇ Satisfies the following conditions: 1.3 < f ₄₇ /f＜1.7。

Further, the object side surface curvature radius R of the second lens ₃ Radius of curvature R of image side surface ₄ Satisfies the following conditions: 1.5 < R ₃ /R ₄ ＜1.7。

Further, the total optical length TTL of the optical lens and the sum Σ CT of the central thicknesses of the first lens element to the seventh lens element along the optical axis respectively satisfy: 0.6 <. Sigma CT/TTL < 0.7.

Compared with the prior art, the invention has the beneficial effects that: the lens shape and focal power combination between the lenses are reasonably matched, so that the effects of 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 of which:

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

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

Fig. 3 is a graph showing a relative illuminance of the optical lens in embodiment 1 of the present invention.

Fig. 4 is a MTF graph of the optical lens in embodiment 1 of the present invention.

Fig. 5 is a graph illustrating axial aberration of the optical lens in embodiment 1 of the present invention.

Fig. 6 is a vertical axis chromatic aberration diagram of the optical lens in embodiment 1 of the present invention.

Fig. 7 is a schematic structural diagram of an optical lens system according to embodiment 2 of the present invention.

Fig. 8 is a field curvature graph of the optical lens in embodiment 2 of the present invention.

Fig. 9 is a graph showing a relative illuminance of the optical lens in embodiment 2 of the present invention.

Fig. 10 is a MTF graph of the optical lens in embodiment 2 of the present invention.

Fig. 11 is a graph illustrating axial aberration of the optical lens system in embodiment 2 of the present invention.

Fig. 12 is a vertical axis chromatic aberration graph of the optical lens in embodiment 2 of the present invention.

Fig. 13 is a schematic structural diagram of an optical lens system according to embodiment 3 of the present invention.

Fig. 14 is a field curvature graph of the optical lens in embodiment 3 of the present invention.

Fig. 15 is a graph showing a relative illuminance of the optical lens in embodiment 3 of the present invention.

Fig. 16 is a MTF graph of the optical lens in embodiment 3 of the present invention.

Fig. 17 is a graph illustrating axial aberration of the optical lens in embodiment 3 of the present invention.

Fig. 18 is a vertical axis chromatic aberration diagram of the optical lens in embodiment 3 of the present invention.

Fig. 19 is a schematic structural diagram of an optical lens system according to embodiment 4 of the present invention.

Fig. 20 is a field curvature graph of the optical lens in embodiment 4 of the present invention.

Fig. 21 is a graph showing the relative illuminance of the optical lens in embodiment 4 of the present invention.

Fig. 22 is a MTF graph of the optical lens in embodiment 4 of the present invention.

Fig. 23 is a graph showing axial aberration of the optical lens in embodiment 4 of the present invention.

Fig. 24 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 used only to distinguish one feature from another, and do not represent any limitation on the features. Thus, the first lens discussed below may also be referred to as the second lens or the third lens without departing from the teachings of the present invention.

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

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

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

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 image side surface of the first lens is a concave surface, so that marginal field-of-view light rays can be collected as far as possible and enter the rear optical lens, and large-angle light ray collection is realized. Furthermore, the refractive index Nd of the first lens is larger than 1.70, and the first lens with higher refractive index is adopted, so that the effective working caliber of the first lens is favorably reduced, and the overlarge caliber of a lens at the rear end of the optical lens caused by the excessive divergence of light rays is avoided.

In some embodiments, the second lens 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 trend of the light rays is in smooth transition. The object side surface of the second lens is a convex surface, and the image side surface of the second lens is a concave surface, so that transition is facilitated and light rays which are deflected excessively from the first lens are adjusted.

In some embodiments, the third lens element may have a positive focal power, which is beneficial for further converging light rays and simultaneously reducing the deflection angle of the light rays, so that the light rays tend to transition smoothly.

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. Fourth lens objective side and image side are the convex surface, not only can reduce the ghost energy of fourth lens objective side light reflection, but also can reduce the coma that fourth lens self produced, promote optical lens's image quality.

In some embodiments, the fifth lens element may have a negative focal power, which is beneficial to balance various aberrations generated by the optical lens and improve the imaging quality of the optical lens. The object side surface and the image side surface of the fifth lens are concave surfaces, coma generated by the fifth lens can be reduced, and the imaging quality of the optical lens is improved.

In some embodiments, the sixth lens element may have a negative focal power, which is beneficial to increase an imaging area of the optical lens and improve the imaging quality of the optical lens. The object side surface of the sixth lens is a concave surface, and the image side surface of the sixth lens is a convex surface, so that the field curvature of the optical lens can be balanced, and the imaging quality of the optical lens is improved.

In some embodiments, the seventh lens element may have positive optical power, which is beneficial to suppress the angle of the peripheral field of view incident on the imaging plane, so as to effectively transmit more light beams to the imaging plane, thereby improving the imaging quality of the optical lens. The object side surface of the seventh lens is a convex surface, so that the relative illumination of the edge field of view is favorably improved, the generation of a dark corner is avoided, and the imaging quality 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 object-side surface of the fourth lens, so as to reduce the occurrence of ghost images of the optical lens, and to converge a range of light rays emitted from a front end of the optical lens, thereby reducing a rear end aperture of the optical lens.

In some embodiments, the aperture value FNO of the optical lens satisfies: FNO of 1.60 or less. The range is satisfied, the large aperture characteristic is favorably realized, and the definition of the image can be ensured in a low-light environment or at night.

In some embodiments, the maximum field angle FOV of the optical lens satisfies: 150 < FOV < 180. 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 < 20 deg. Satisfying the above range, a larger tolerance error range can be provided between the CRA of the optical lens and the CRA of the chip photosensitive element, and the adaptability of the optical lens to the image sensor is improved.

In some embodiments, the total optical length TTL and the effective focal length f of the optical lens satisfy: TTL/f is more than 7.0 and less than 9.0. 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 1.3 and less than 1.9. The wide-angle characteristic can be realized by meeting the range, so that the requirement of large-range shooting is met, the large image surface characteristic can be realized, and the imaging quality of the optical lens is improved.

In some embodiments, the maximum field angle FOV of the optical lens and the aperture value FNO satisfy: 80 < FOV/FNO < 110. Satisfying the above range is advantageous for enlarging the angle of view of the optical lens and increasing the aperture of the optical lens, and realizes the characteristics of a wide angle and a large aperture. The realization of the wide-angle characteristic is favorable for the optical lens to acquire more scene information, the requirement of large-range detection is met, and the realization of the large aperture characteristic is favorable for improving the problem that the relative brightness of the edge field of view is reduced rapidly caused by the wide angle, so that the realization of the wide-angle characteristic is also favorable for acquiring more scene information.

In some embodiments, the effective focal length f of the optical lens satisfies the following relationship with the maximum field angle FOV and the true image height IH corresponding to the maximum field angle: 85 DEG < f × FOV/IH < 120 deg. Satisfy above-mentioned scope, can balance the demand of surveying on a large scale and high-quality formation of image, promote optical lens's suitability.

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: -3.5 < f ₁ The/f is less than 0. Satisfying above-mentioned scope, can making first lens have appropriate negative power, be favorable to incident light refraction angle change comparatively milder, avoid refraction change too strong and produce too much aberration, help more light to get into rear optical system simultaneously, increase the illumination and promote optical lens's image quality.

In some embodiments, the effective focal length f of the optical lens and the focal length f of the second lens are different ₂ Satisfies the following conditions: f is more than 100.0 ₂ And/f is calculated. Satisfying the above range, the second lens can have a proper positive refractive power, and by reasonably defining the refractive power (e.g., a small refractive power) of the second lens, the influence of the second lens on the back focus offset under high and low temperature conditions can be reduced, thereby improving the temperature performance of the optical lens.

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 5.0 ₃ The/f is less than 11.0. The third lens has appropriate positive focal power, so that the light trend is smoothly transited, 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 f of the fourth lens are ₄ Satisfies the following conditions: f is more than 0 ₄ The/f is less than 1.5. The optical lens meets the range, the fourth lens has proper positive focal power, the light trend is favorably and stably transited, 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 f of the fifth lens ₅ F is more than-2.5 ₅ The/f is less than 0. The fifth lens has proper negative focal power, so that various aberrations of the optical lens can be balanced, 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 f of the sixth lens ₆ Satisfies the following conditions: -22.0 < f ₆ F < -15.0. The sixth lens has appropriate negative focal power, so that various aberrations of the optical lens can be balanced, and the imaging quality of the optical lens is improved.

In some embodiments, the effective focal length of the optical lensf and focal length f of seventh lens ₇ Satisfies the following conditions: f is more than 0 ₇ The/f is less than 2.5. The seventh lens has appropriate positive focal power, so that the light convergence capability of the peripheral field of view is improved, and the relative illumination of the optical lens is improved.

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: -3.0 < f ₁₃ And/f is less than-2.0. Satisfy above-mentioned scope, through the focal power of rational distribution first lens to third lens, be favorable to reducing spherical aberration and the curvature of field that optical lens front end lens produced, promote optical lens's imaging 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 seventh lens ₄₇ Satisfies the following conditions: 1.3 < f ₄₇ The/f is less than 1.7. Satisfying the above range, it is favorable to balancing the distortion and astigmatism generated by the front lens of the optical lens and improving the imaging quality of the optical lens by reasonably distributing the focal powers of the fourth lens to the seventh lens.

In some embodiments, the second lens has a radius of curvature of the object side R ₃ Radius of curvature R of image side surface ₄ Satisfies the following conditions: r is more than 1.5 ₃ /R ₄ Is less than 1.7. The optical path difference between the center and the periphery of the second lens can be reduced by adopting the shape of the lens close to the concentric circle, so that the distortion of the optical lens can be corrected.

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 < 0.7. 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 a quadric coefficient, and A, B, C, D, E, F, G and H are second-order, fourth-order, sixth-order, eighth-order, tenth-order, twelfth-order, fourteenth-order and sixteenth-order coefficients, 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 optical filter G1, and a cover glass G2.

The first lens L1 has negative focal power, and the object side surface S1 is a convex surface, and the image side surface S2 is a concave surface;

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

the third lens L3 has positive focal power, and the object side surface S5 is a concave surface, and the image side surface S6 is a convex surface;

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 fifth lens L5 has negative focal power, and both the object-side surface S9 and the image-side surface S10 are concave;

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 seventh lens L7 has positive focal power, and both the object-side surface S13 and the image-side surface S14 are convex surfaces;

the optical filter G1, the object side surface S15 and the image side surface S16 are both planes;

a cover glass G2, of which both the object-side surface S17 and the image-side surface S18 are flat surfaces;

the image formation 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 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 +/-0.02 mm, which shows that the optical lens can excellently correct the field curvature.

Fig. 3 shows a relative illuminance graph of example 1, 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 is still greater than 80% at the maximum half field angle, indicating that the optical lens has excellent relative illuminance.

Fig. 4 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 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. 5 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 shift amount of the axial aberration is controlled within ± 15 μm, which indicates that the optical lens can correct the axial aberration well.

Fig. 6 is a graph showing the vertical axis chromatic aberration of example 1, in which the chromatic aberration at different image heights on the image formation plane is shown for each wavelength with respect to the center wavelength (0.55 μm), the horizontal axis shows the vertical axis chromatic aberration value (unit: μm) for each wavelength with respect to the center wavelength, and the vertical axis shows the 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. 7, 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 optical filter G1, and a cover glass G2.

The first lens L1 has negative focal power, and the object side surface S1 of the first lens L is a convex surface, and the image side surface S2 of the first lens L is a concave surface;

the third lens L3 has positive focal power, and the object side surface S5 is a convex surface, and the image side surface S6 is a concave surface;

a diaphragm ST;

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

the object side surface S17 and the image side surface S18 of the protective glass G2 are both flat surfaces;

the image formation surface S19 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. 8 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 +/-0.03 mm, which shows that the optical lens can excellently correct the field curvature.

Fig. 9 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 is still greater than 80% at the maximum half field angle, indicating that the optical lens has excellent relative illuminance.

Fig. 10 shows a Modulation Transfer Function (MTF) graph of example 2, 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. 11 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 ± 10 μm, indicating that the optical lens can correct the axial aberration well.

Fig. 12 is a graph showing a vertical axis chromatic aberration of example 2, in which the chromatic aberration at different image heights on the image formation plane is shown for each wavelength with respect to the center wavelength (0.55 μm), the horizontal axis shows the vertical axis chromatic aberration value (unit: μm) for each wavelength with respect to the center wavelength, and the vertical axis shows the 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 +/-2 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. 13, 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 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 third lens L3 has positive focal power, and both the object side surface S5 and the image side surface S6 are convex surfaces;

a diaphragm ST;

the fifth lens L5 has negative focal power, and both the object side surface S9 and the image side surface S10 are concave surfaces;

the optical filter G1 is provided with a plane on both the object side surface S15 and the image side surface S16;

the image formation surface S19 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. 14 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 +/-0.03 mm, which shows that the optical lens can excellently correct the field curvature.

Fig. 15 shows a graph of relative illuminance for example 3, 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. 16 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. 17 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 shift amount of the axial aberration is controlled within ± 20 μm, which indicates that the optical lens can correct the axial aberration well.

Fig. 18 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 +/-1 μm, 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. 19, 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 optical filter G1, and a cover glass G2.

a diaphragm ST;

the image formation surface S19 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. 20 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. 21 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 luminance value of the optical lens is still greater than 60% at the maximum half field angle, which indicates that the optical lens has better relative luminance.

Fig. 22 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 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. 23 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 shift amount of the axial aberration is controlled within ± 20 μm, which indicates that the optical lens can correct the axial aberration well.

Fig. 24 is a graph showing the vertical axis chromatic aberration of example 4, in which the chromatic aberration at different image heights on the image formation plane is shown for each wavelength with respect to the center wavelength (0.55 μm), the horizontal axis shows the vertical axis chromatic aberration value (unit: μm) for each wavelength with respect to the center wavelength, and the vertical axis shows the 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 +/-2 μm, which shows that the optical lens can excellently correct the chromatic aberration of the marginal field of view and the secondary spectrum of the whole image surface.

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

TABLE 5

In summary, the optical lens according to the embodiment of the invention realizes the effects of large field of view, large aperture and miniaturization by reasonably matching the combination of the lens shape and the focal power between the lenses.

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

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that various changes and modifications can be made by those skilled in the art without departing from the spirit of the invention, and these changes and modifications are all within the scope of the invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

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

the image side surface of the first lens is a concave surface;

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

a third lens having positive optical power;

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 more than 7.0 and less than 9.0.

3. An optical lens according to claim 1, characterized in that the maximum field angle FOV and the aperture value FNO of the optical lens satisfy: 80 < FOV/FNO < 110.

4. An optical lens according to claim 1, characterized in that the effective focal length f of the optical lens and the focal length f of the first lens are ₁ Satisfies the following conditions: -3.5 < f ₁ /f＜0。

5. An optical lens according to claim 1, characterized in that the effective focal length f of the optical lens and the focal length f of the fourth lens are ₄ Satisfies the following conditions: f is more than 0 ₄ /f＜1.5。

6. An optical lens according to claim 1, characterized in that the effective focal length f of the optical lens and the focal length f of the seventh lens ₇ Satisfies the following conditions: f is more than 0 ₇ /f＜2.5。

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: -3.0 < f ₁₃ /f＜-2.0。

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 lens to the seventh lens are ₄₇ Satisfies the following conditions: 1.3 < f ₄₇ /f＜1.7。

9. An optical lens barrel according to claim 1, wherein the object side radius of curvature R of the second lens ₃ Radius of curvature R of image side surface ₄ Satisfies the following conditions: r is more than 1.5 ₃ /R ₄ ＜1.7。

10. An optical lens according to claim 1, wherein a total optical length TTL of the optical lens and a sum Σ CT of central thicknesses of the first lens to the seventh lens along an optical axis, respectively, satisfy: 0.6 <. Sigma CT/TTL < 0.7.