CN114252981B - optical lens - Google Patents

Abstract

The application provides an optical lens. The optical lens sequentially comprises from an object side to an image side along an optical axis: a first lens which is a meniscus lens having negative optical power; a second lens which is a biconcave lens having negative optical power; a third lens which is a biconvex lens having positive optical power; a fourth lens which is a biconcave lens having negative optical power; a fifth lens which is a biconvex lens having positive optical power; a sixth lens which is a biconvex lens having positive optical power; a seventh lens which is a biconvex lens having positive optical power; a light filter; an imaging surface. The application solves the problems of large target surface, large aperture, high resolution and miniaturization of the optical lens in the prior art, which are difficult to be simultaneously considered.

Description

Optical lens

Technical Field

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

Background

With the rapid development of the autopilot technology, the optical lens is increasingly applied in the autopilot field, especially in the aspects of vehicle-mounted lenses, laser radars and the like, and besides the requirements of high pixel and small volume, other requirements of the optical lens are also increasingly increased, such as large field angle, long focal length, small FNO, high illumination, small distortion and the like, and the optical lens needs special requirements of performance according to different applications. But some properties tend to be difficult to achieve at the same time.

With the rapid development of the laser radar field, the following problems still exist in the current optical lens: 1. the imaging target surface of the existing optical fixed-focus lens is small, and most of the imaging target surface is concentrated at 1/2.7 inch; the actual use requirements cannot be met. 2. The existing fixed focus lens in the market is generally smaller in aperture, and F numbers are F1.6 and above. 3. The number of optical lenses of the optical lens is large, the imaging quality is improved, and meanwhile, the size of the whole optical lens is increased, so that the miniaturization design requirement cannot be met.

That is, the optical lens in the prior art has a problem that it is difficult to achieve both a large target surface, a large aperture, a high resolution and miniaturization.

Disclosure of Invention

The application mainly aims to provide an optical lens, which solves the problems that the optical lens in the prior art has large target surface, large aperture, high resolution and miniaturization are difficult to be compatible.

In order to achieve the above object, the present application provides an optical lens comprising, in order from an object side to an image side along an optical axis: a first lens which is a meniscus lens having negative optical power; a second lens which is a biconcave lens having negative optical power; a third lens which is a biconvex lens having positive optical power; a fourth lens which is a biconcave lens having negative optical power; a fifth lens which is a biconvex lens having positive optical power; a sixth lens which is a biconvex lens having positive optical power; a seventh lens which is a biconvex lens having positive optical power; a light filter; an imaging surface.

Further, the optical lens further includes an aperture stop disposed between the third lens and the fourth lens.

Further, the fourth lens and the fifth lens are glued to form a glued lens group.

Further, a combined focal length f of the fourth lens and the fifth lens _g1 The total focal length f of the optical lens and the field angle FOV of the optical lens satisfy the following conditions: f is less than or equal to 5.3 _g1 /f)*tan(FOV/3)≤7.2。

Further, the first lens, the second lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens are all glass spherical lenses, and the third lens is a glass spherical lens or a glass aspherical lens.

Further, the object side surface of the first lens is a convex surface, and the image side surface of the first lens is a concave surface.

Further, the center radius of curvature R2 of the image side of the first lens and the center radius of curvature R3 of the object side of the second lens satisfy: (R2-R3)/(R2+R3) is less than or equal to-1.1.

Further, the requirements between the optical back focal length BFL of the optical lens and the total system length TTL of the optical lens are: BFL/TTL is less than or equal to 0.35.

Further, the focal length f1 of the first lens satisfies: f1 is less than or equal to-26.5 mm; the focal length f3 of the third lens is satisfied; f3 is less than or equal to 12mm; the focal length f5 of the fifth lens satisfies: f3 is less than or equal to 12mm.

Further, abbe number V of the second lens _d2 The method meets the following conditions: v (V) _d2 Less than or equal to 53; abbe number V of the third lens _d3 The method meets the following conditions: v (V) _d3 More than or equal to 18; abbe number V of the sixth lens _d6 The method meets the following conditions: v (V) _d6 ≤55。

Further, the refractive index N of the second lens _d2 The method meets the following conditions: n (N) _d2 Less than or equal to 1.65; refractive index N of fourth lens _d4 The method meets the following conditions: n (N) _d4 Less than or equal to 1.93; refractive index N of seventh lens _d7 The method meets the following conditions: n (N) _d7 ≤1.71。

By applying the technical scheme of the application, the optical lens sequentially comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an optical filter and an imaging surface from an object side to an image side along an optical axis, wherein the first lens is a meniscus lens with negative focal power; the second lens is a biconcave lens with negative focal power; the third lens is a biconvex lens with positive focal power; the fourth lens is a biconcave lens with negative focal power; the fifth lens is a biconvex lens with positive focal power; the sixth lens is a biconvex lens with positive focal power; the seventh lens is a biconvex lens having positive optical power.

Through carrying out planning setting to the focal power and the shape of each lens, be favorable to improving the resolution capability of optical lens, be favorable to guaranteeing the characteristics of high resolution for optical lens can realize better distortion control and outstanding imaging characteristics. Meanwhile, the optical lens can still ensure better working performance and better imaging quality under the extreme temperature environment state. The application is a seven-piece optical lens, the number of the adopted lenses is less, the system overall length of the optical lens is ensured to be smaller, the size of the optical lens is effectively reduced, and the miniaturization is ensured. In addition, the optical lens has the advantages of large target surface, low cost and large aperture.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the application. In the drawings:

fig. 1 is a schematic view showing the structure of an optical lens according to a first embodiment of the present application;

FIG. 2 shows a graph of the optical transfer function MTF of the optical lens of FIG. 1 at normal temperature in the visible light band;

FIG. 3 shows a field curvature diagram of the optical lens of FIG. 1 in the visible light band;

FIG. 4 shows a distortion diagram of the optical lens of FIG. 1 in the visible light band;

FIG. 5 shows a lateral fan of the optical lens of FIG. 1 in the visible light band;

FIG. 6 shows a point-column diagram of the optical lens of FIG. 1 in the visible light band;

fig. 7 is a schematic structural diagram of an optical lens according to a second embodiment of the present application;

FIG. 8 shows a graph of the optical transfer function MTF of the optical lens of FIG. 7 at ambient conditions in the visible light band;

FIG. 9 shows a field curvature diagram of the optical lens of FIG. 7 in the visible light band;

FIG. 10 shows a distortion plot of the optical lens of FIG. 7 in the visible light band;

FIG. 11 shows a lateral fan view of the optical lens of FIG. 7 in the visible light band;

fig. 12 shows a point diagram of the optical lens in fig. 7 in the visible light band.

Wherein the above figures include the following reference numerals:

l1, a first lens; l2, a second lens; l3, a third lens; STOP and aperture STOP; l4, a fourth lens; l5, a fifth lens; l6, sixth lens; l7, seventh lens; l8, an optical filter; IMA, imaging plane.

Detailed Description

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

It is noted that all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs unless otherwise indicated.

In the present application, unless otherwise indicated, terms of orientation such as "upper, lower, top, bottom" are used generally with respect to the orientation shown in the drawings or with respect to the component itself in the vertical, upright or gravitational direction; also, for ease of understanding and description, "inner and outer" refers to inner and outer relative to the profile of each component itself, but the above-mentioned orientation terms are not intended to limit the present application.

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, then 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 near the object side becomes the object side of the lens, and the surface of each lens near the image side is called the image side of the lens. The determination of the surface shape in the paraxial region can be performed by a determination method by a person skilled in the art by positive or negative determination of the concave-convex with R value (R means the radius of curvature of the paraxial region, and generally means the R value on a lens database (lens data) in optical software). In the object side surface, when the R value is positive, the object side surface is judged to be convex, and when the R value is negative, the object side surface is judged to be concave; in the image side, the concave surface is determined when the R value is positive, and the convex surface is determined when the R value is negative. The left side is the object side and the right side is the image side.

The application provides an optical lens, which aims to solve the problems that the optical lens in the prior art has a large target surface, a large aperture, high resolution and miniaturization are difficult to take into account at the same time.

As shown in fig. 1 to 12, the optical lens sequentially includes, from an object side to an image side along an optical axis, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an optical filter, and an imaging plane, wherein the first lens is a meniscus lens having negative optical power; the second lens is a biconcave lens with negative focal power; the third lens is a biconvex lens with positive focal power; the fourth lens is a biconcave lens with negative focal power; the fifth lens is a biconvex lens with positive focal power; the sixth lens is a biconvex lens with positive focal power; the seventh lens is a biconvex lens having positive optical power.

Through carrying out planning setting to the focal power and the shape of each lens, be favorable to improving the resolution capability of optical lens, be favorable to guaranteeing the characteristics of high resolution for optical lens can realize better distortion control and outstanding imaging characteristics. Meanwhile, the optical lens can still ensure better working performance and better imaging quality under the extreme temperature environment state. The application is a seven-piece optical lens, the number of the adopted lenses is less, the system overall length of the optical lens is ensured to be smaller, the size of the optical lens is effectively reduced, and the miniaturization is ensured. In addition, the optical lens has the advantages of large target surface, low cost and large aperture.

Specifically, the imaging target surface of the optical lens can support a sensor (CCD/CMOS) camera of 1/1.8 inch at most, so that the requirement of high resolution of equipment is met, the high resolution of the optical lens is effectively realized, the imaging quality is ensured, and meanwhile, the imaging target surface can be used in an environment of-40-120 ℃ so as to meet the application requirements at different temperatures. The mechanical total length of the optical lens is not more than 30mm, so that the overall size of the optical lens is effectively ensured to be smaller, and the miniaturization is facilitated. The full-view field MTF value of the optical lens reaches over 0.5 to 0.6 under the condition of 100lp/mm, so that the excellent imaging characteristic of the optical lens can be ensured. The optical lens has a larger aperture and an F number of 1.4, and is particularly suitable for monitoring requirements under low-illumination conditions.

Specifically, the optical lens further includes an aperture stop disposed between the third lens and the fourth lens. Through setting up aperture stop for aperture stop can effectively be to the receipts of the light in getting into the optical lens, effectively plan the light trend, is favorable to reducing the bore of lens simultaneously, makes more compacter between each lens of optical lens, in order to guarantee miniaturization.

Specifically, the fourth lens and the fifth lens are glued to form a glued lens group. By arranging the cemented lens group, the optical lens can be effectively ensured to have higher resolving power. Meanwhile, the air interval between the fourth lens and the fifth lens can be reduced, so that the whole optical lens is more compact, and the sensitivity of the fourth lens and the fifth lens can be reduced.

Specifically, the combined focal length f of the fourth lens and the fifth lens _g1 The total focal length f of the optical lens and the field angle FOV of the optical lens satisfy the following conditions: f is less than or equal to 5.3 _g1 /f)*tan(FOV/3)≤7.2。

Specifically, the first lens, the second lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens are all glass spherical lenses, and the third lens is a glass spherical lens or a glass aspherical lens. By limiting the material of each lens, it is advantageous to ensure low cost. By selecting an aspherical lens, the curvature is continuously changed from the center of the lens to the periphery of the lens. Unlike a spherical lens having a constant curvature from the center of the lens to the periphery of the lens, an aspherical lens has a better radius of curvature characteristic, and has advantages of improving distortion aberration and improving astigmatic aberration. By adopting the aspherical lens, aberration occurring at the time of imaging can be eliminated as much as possible, thereby improving imaging quality.

Specifically, the object side surface of the first lens is a convex surface, and the image side surface of the first lens is a concave surface. In addition, in the present application, the object side surface of the second lens is a concave surface, and the image side surface is a concave surface; the object side surface of the third lens is a convex surface, and the image side surface is a convex surface; the object side surface of the fourth lens is a concave surface, and the image side surface is a concave surface; the object side surface of the fifth lens is a convex surface, and the image side surface is a convex surface; the object side surface of the sixth lens is a convex surface, and the image side surface is a convex surface; the seventh lens element has a convex object-side surface and a convex image-side surface. Through the reasonable distribution of the surface types of each lens, the shape of the lens is beneficial to processing, and the manufacturing cost of the optical lens is low.

Specifically, the center radius of curvature R2 of the image side surface of the first lens element and the center radius of curvature R3 of the object side surface of the second lens element satisfy: (R2-R3)/(R2+R3) is less than or equal to-1.1.

Specifically, the requirements between the optical back focal length BFL of the optical lens and the total system length TTL of the optical lens are: BFL/TTL is less than or equal to 0.35.

Specifically, the focal length f1 of the first lens satisfies: f1 is less than or equal to-26.5 mm; the focal length f3 of the third lens is satisfied; f3 is less than or equal to 12mm; the focal length f5 of the fifth lens satisfies: f3 is less than or equal to 12mm.

Specifically, the Abbe number V of the second lens _d2 The method meets the following conditions: v (V) _d2 Less than or equal to 53; abbe number V of the third lens _d3 The method meets the following conditions: v (V) _d3 More than or equal to 18; abbe number V of the sixth lens _d6 The method meets the following conditions: v (V) _d6 ≤55。

Specifically, the refractive index N of the second lens _d2 The method meets the following conditions: n (N) _d2 Less than or equal to 1.65; refractive index N of fourth lens _d4 The method meets the following conditions: n (N) _d4 Less than or equal to 1.93; refractive index N of seventh lens _d7 The method meets the following conditions: n (N) _d7 ≤1.71。

Specific embodiments of the optical lens of the present application are described in detail below with reference to the accompanying drawings.

Example 1

As shown in fig. 1 to 6, a first embodiment of the present application is described. Fig. 1 is a schematic structural diagram of an optical lens according to a first embodiment of the present application.

As shown in fig. 1, the optical lens sequentially includes, from an object side to an image side: a first lens L1, a second lens L2, a third lens L3, an aperture STOP, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an optical filter L8, and an imaging plane IMA.

In the first embodiment, the curvature radius R, the center thickness Tc, the refractive index Nd, the abbe number Vd, and the cone coefficient k of each lens of the optical lens satisfy the conditions shown in table 1:

TABLE 1

In the schematic structural diagram of the optical lens shown in fig. 1, the mirror numbers in table 1 are the numbers of the lenses from left to right. Wherein the third lens L3 is an aspherical lens.

The aspherical cone coefficients can be defined by the following aspherical formula, but are not limited to the following representation:

wherein Z is the axial sagittal height of the aspheric surface in the Z direction; r is the height of the aspheric surface; c is the curvature of the fitting sphere, and the numerical value is the reciprocal of the curvature radius; k is a fitting cone coefficient; a-F are 4 th, 6 th, 8 th, 10 th, 12 th, 14 th order polynomial coefficients of the aspherical polynomial. The following table 2 gives the higher order coefficients A, B, C, D, E, F that can be used for the aspherical lens in embodiment one.

Mirror number

A

B

C

D

E

F

5

-4.950E-07

-4.950E-07

2.189E-08

2.267E-10

-2.170E-10

-4.163E-11

6

6.505E-07

-2.436E-07

-4.738E-08

-3.405E-09

4.103E-11

5.908E-11

TABLE 2

It should be noted that the data listed in the above table are preferred data of the present application, and are not intended to limit the present application, and any person skilled in the art, after referring to the present application, should make appropriate changes to the parameters or settings thereof, and still fall within the scope of the present application.

The optical lens provided by the embodiment has the following optical technical indexes:

the total system length TTL of the optical lens meets the following conditions: TTL is less than or equal to 30mm;

the total focal length f of the optical lens is 5.4mm;

the field angle FOV of the optical lens is 91.6 °;

the optical distortion of the optical lens is-17.4%;

aperture of optical lens: FNO is less than or equal to 1.4;

optical lens image plane size:

in the present embodiment, the combined focal length fg1 of the fourth lens and the fifth lens, the total focal length f of the optical lens, and the field angle FOV of the optical lens satisfy: (fg 1/f) ×tan (FOV/3) =5.3; the center curvature radius R2 of the image side of the first lens and the object side of the second lensThe center radius of curvature R3 of (c) satisfies: (r2—r3)/(r2+r3) = -1.38; the optical back focal length BFL of the optical lens and the total system length TTL of the optical lens satisfy the following conditions: BFL/ttl=0.308; the focal length f1 of the first lens is-29.48 mm; the focal length f3 of the third lens is 10.88mm; the focal length f5 of the fifth lens is 8.15mm; abbe number V of the second lens _d2 41.3; abbe number V of the third lens _d3 20.7; abbe number V of the sixth lens _d6 48.1; refractive index N of the second lens _d2 1.58; refractive index N of fourth lens _d4 1.85; refractive index N of seventh lens _d7 1.62.

As shown in fig. 2, an MTF curve chart of the optical transfer function of the optical lens of the first embodiment at normal temperature in the visible light band is shown. The optical transfer function is a more accurate, visual and common way for evaluating the imaging quality of an optical lens, and the higher and smoother the curve is, which shows that the better the imaging quality of the system is, the better the correction of various aberrations (such as spherical aberration, coma aberration, astigmatism, field curvature, axial chromatic aberration, vertical chromatic aberration and the like) is carried out. As shown in the figure, the optical transfer function MTF curve graph of the optical lens in the normal temperature state of the visible light part is smoother and more concentrated, and the full-view field (half image height Y' =4.0 mm) MTF average value reaches more than 0.6; the optical lens provided by the embodiment can reach higher imaging requirements.

As shown in fig. 3, a field curvature diagram of the optical lens in the visible light band according to the first embodiment is shown. As can be seen from the figure, the curvature of field of the optical lens of the first embodiment is controlled within ±0.05mm. The field Qu Youchen "field curvature". When the lens is curved, the intersection point of the whole light beam does not coincide with the ideal image point, and although a clear image point can be obtained at each specific point, the whole image plane is a curved surface. T represents the meridian curvature and S represents the sagittal curvature. The field curvature curve shows the distance of the current focal plane or image plane to the paraxial focal plane as a function of the field coordinates, and the meridian field curvature data is the distance measured along the Z-axis from the currently determined focal plane to the paraxial focal plane and is measured on the meridian (YZ-plane). The sagittal field curvature data measures the distance measured in a plane perpendicular to the meridian plane, the base line in the diagram being on the optical axis, the top of the curve representing the maximum field of view (angle or height), and no units being placed on the longitudinal axis, since the curve is always normalized by the maximum radial field of view.

As shown in fig. 4, a distortion chart of the optical lens in the visible light band according to the first embodiment is shown. As can be seen from the figure, the distortion of the optical lens is well controlled within-20%. In general, distortion is actually a generic term for perspective distortion inherent to optical lenses, i.e., distortion due to perspective, which is very detrimental to the imaging quality of photographs, after all, for the purpose of photography, but is not exaggerated, but cannot be eliminated and can only be improved because it is an inherent characteristic of lenses (convex lens converging rays, concave lens diverging rays). As can be seen from fig. 4, the distortion of the optical lens provided in the first embodiment of the present application is only-17.4%, so that the distortion is set to balance the focal length, the angle of view and the size of the corresponding camera target surface, and the distortion caused by the distortion can be corrected by post image processing.

Fig. 5 shows a transverse fan diagram of the optical lens in the visible light band according to the present application. The graph shows that the curves in the transverse fan graph are concentrated, that is, the spherical aberration and dispersion of the optical lens are well controlled.

Fig. 6 is a point diagram of the optical lens of the present application in the visible light range. As can be seen from the figure, the optical lens has smaller spot radius, is more concentrated, and has good corresponding aberration and coma aberration.

Example two

As shown in fig. 7 to 12, a second embodiment of the present application is described. Fig. 7 is a schematic structural diagram of an optical lens according to a second embodiment of the present application.

As shown in fig. 7, the optical lens includes, in order from an object side to an image side: a first lens L1, a second lens L2, a third lens L3, an aperture STOP, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an optical filter L8, and an imaging plane IMA.

In the second embodiment, the curvature radius R, the center thickness Tc, the refractive index Nd, the abbe number Vd, and the cone coefficient k of each lens of the optical lens satisfy the conditions shown in table 3:

TABLE 3 Table 3

In the schematic configuration of the optical lens shown in fig. 7, the mirror numbers in table 3 are the numbers of the lenses from left to right. Wherein the third lens L3 is an aspherical lens.

The aspherical conic coefficient can be defined by the formula (1) in the first embodiment. The following table 4 gives the higher order coefficients A, B, C, D, E, F of the aspherical lenses that can be used in embodiment two.

Mirror number

A

B

C

D

E

F

5

-1.459E-06

2.418E-07

2.094E-08

-2.057E-09

-8.338E-10

0

6

-4.122E-06

-1.190E-06

-1.578E-07

-4.536E-09

3.943E-09

0

TABLE 4 Table 4

It should be noted that the data listed in the above table are preferred data of the present application, and are not intended to limit the present application, and any person skilled in the art, after referring to the present application, should make appropriate changes to the parameters or settings thereof, and still fall within the scope of the present application.

The optical lens provided by the embodiment has the following optical technical indexes:

the total system length TTL of the optical lens meets the following conditions: TTL is less than or equal to 30mm;

the total focal length f of the optical lens is 5.1mm;

the field angle FOV of the optical lens is 96.0 °;

the optical distortion of the optical lens is-18.5%;

aperture of optical lens: FNO is less than or equal to 1.4;

optical lens image plane size:

in the present embodiment, the combined focal length fg1 of the fourth lens and the fifth lens, the total focal length f of the optical lens, and the field angle FOV of the optical lens satisfy: (fg 1/f) ×tan (FOV/3) =7.2; the center radius of curvature R2 of the image side surface of the first lens and the center radius of curvature R3 of the object side surface of the second lens satisfy: (r2—r3)/(r2+r3) = -1.19; the optical back focal length BFL of the optical lens and the total system length TTL of the optical lens satisfy the following conditions: BFL/ttl=0.277; the focal length f1 of the first lens is-2745mm; the focal length f3 of the third lens is 9.91mm; the focal length f5 of the fifth lens is 8.13mm; abbe number V of the second lens _d2 46.6; abbe number V of the third lens _d3 20.7; abbe number V of the sixth lens _d6 48.1; refractive index N of the second lens _d2 1.58; refractive index N of fourth lens _d4 1.85; refractive index N of seventh lens _d7 1.59.

As shown in fig. 8, an MTF curve chart of the optical transfer function of the optical lens of the second embodiment in the normal temperature state of the visible light band is shown. As shown in the figure, the optical transfer function MTF curve graph of the optical lens in the normal temperature state of the visible light part is smoother and more concentrated, and the full-view field (half image height Y' =4.0 mm) MTF average value reaches more than 0.6; the optical lens provided by the embodiment can reach higher imaging requirements.

As shown in fig. 9, a field curvature diagram of the optical lens in the visible light band according to the second embodiment is shown. As can be seen from the figure, the curvature of field of the optical lens of the second embodiment is controlled within ±0.05mm. The field Qu Youchen "field curvature". When the lens is curved, the intersection point of the whole light beam does not coincide with the ideal image point, and although a clear image point can be obtained at each specific point, the whole image plane is a curved surface. T represents the meridian curvature and S represents the sagittal curvature. The field curvature curve shows the distance of the current focal plane or image plane to the paraxial focal plane as a function of the field coordinates, and the meridian field curvature data is the distance measured along the Z-axis from the currently determined focal plane to the paraxial focal plane and is measured on the meridian (YZ-plane). The sagittal field curvature data measures the distance measured in a plane perpendicular to the meridian plane, the base line in the diagram being on the optical axis, the top of the curve representing the maximum field of view (angle or height), and no units being placed on the longitudinal axis, since the curve is always normalized by the maximum radial field of view.

As shown in fig. 10, a distortion chart of the optical lens of the second embodiment in the visible light band is shown. As can be seen from the figure, the distortion of the optical lens is well controlled within-20%. In general, distortion is actually a generic term for perspective distortion inherent to optical lenses, i.e., distortion due to perspective, which is very detrimental to the imaging quality of photographs, after all, for the purpose of photography, but is not exaggerated, but cannot be eliminated and can only be improved because it is an inherent characteristic of lenses (convex lens converging rays, concave lens diverging rays). As can be seen from fig. 4, the distortion of the optical lens provided in the second embodiment of the present application is only-18.5%, so that the distortion is set to balance the focal length, the angle of view and the size of the corresponding camera target surface, and the distortion caused by the distortion can be corrected by post image processing.

Fig. 11 is a cross-sectional view of the optical lens of the present application in the visible light range. The graph shows that the curves in the transverse fan graph are concentrated, that is, the spherical aberration and dispersion of the optical lens are well controlled.

As shown in fig. 12, the optical lens of the present application is a point chart in the visible light band. As can be seen from the figure, the optical lens has smaller spot radius, is more concentrated, and has good corresponding aberration and coma aberration.

In summary, the first and second embodiments satisfy the relationships shown in table 5 below.

Conditional formulas/embodiments	Example 1	Example two
			(f g1 /f)*tan(FOV/3)	5.3	7.2
(R2-R3)/(R2+R3)	-1.38	-1.19
			BFL/TTL	0.308	0.277
f1	-29.48	-27.45
			f3	10.88	9.91
f5	8.15	8.13
			V d2	41.3	46.6
V d3	20.7	20.7
			V d6	48.1	48.1
N d2	1.58	1.58
			N d4	1.85	1.85
N d7	1.62	1.59

TABLE 5

It will be apparent that the embodiments described above are merely some, but not all, embodiments of the application. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present application without making any inventive effort, shall fall within the scope of the present application.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the present application. As used herein, the singular is also intended to include the plural unless the context clearly indicates otherwise, and furthermore, it is to be understood that the terms "comprises" and/or "comprising" when used in this specification are taken to specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof.

It should be noted that the terms "first," "second," and the like in the description and the claims of the present application and the above figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that embodiments of the application described herein may be implemented in sequences other than those illustrated or otherwise described herein.

The above description is only of the preferred embodiments of the present application and is not intended to limit the present application, but various modifications and variations can be made to the present application by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims (10)

1. An optical lens is characterized in that, seven lenses, an optical filter (L8) and a lens are arranged in sequence from the object side to the image side along the optical axis,

An imaging plane (IMA);

the seven lenses are sequentially arranged from the object side to the image side along the optical axis: a first lens (L1), the first lens (L1) being a meniscus lens having negative optical power; a second lens (L2), the second lens (L2) being a biconcave lens having negative optical power; a third lens (L3), the third lens (L3) being a biconvex lens having positive optical power; a fourth lens (L4), the fourth lens (L4) being a biconcave lens having negative optical power; a fifth lens (L5), the fifth lens (L5) being a biconvex lens having positive optical power; a sixth lens (L6), the sixth lens (L6) being a biconvex lens having positive optical power; a seventh lens (L7), the seventh lens (L7) being a biconvex lens having positive optical power;

wherein the combined focal length f of the fourth lens (L4) and the fifth lens (L5) _g1 The total focal length f of the optical lens and the field angle FOV of the optical lens satisfy the following conditions: f is less than or equal to 5.3 _g1 /f）*tan（FOV/3）≤7.2。

2. The optical lens according to claim 1, further comprising an aperture STOP (STOP) disposed between the third lens (L3) and the fourth lens (L4).

3. An optical lens according to claim 1, characterized in that the fourth lens (L4) is cemented with the fifth lens (L5) to form a cemented lens group.

4. The optical lens according to claim 1, wherein the first lens (L1), the second lens (L2), the fourth lens (L4), the fifth lens (L5), the sixth lens (L6) and the seventh lens (L7) are all glass spherical lenses, and the third lens (L3) is a glass spherical lens or a glass aspherical lens.

5. The optical lens of claim 1, wherein an object side surface of the first lens is convex and an image side surface of the first lens is concave.

6. The optical lens of any one of claims 1-5, wherein a center radius of curvature R2 of an image side of the first lens and a center radius of curvature R3 of an object side of the second lens satisfy: (R2-R3)/(R2+R3) is less than or equal to-1.1.

7. The optical lens according to any one of claims 1 to 5, wherein the optical back focal length BFL of the optical lens and the total system length TTL of the optical lens satisfy: BFL/TTL is less than or equal to 0.35.

8. The optical lens according to any one of claims 1 to 5, wherein,

the focal length f1 of the first lens satisfies: f1 is less than or equal to-26.5 mm;

the focal length f3 of the third lens is satisfied; f3 is less than or equal to 12mm;

the focal length f5 of the fifth lens satisfies: f5 is less than or equal to 12mm.

9. The optical lens according to any one of claims 1 to 5, wherein,

abbe number V of the second lens _d2 The method meets the following conditions: v (V) _d2 ≤53；

Abbe number V of the third lens _d3 The method meets the following conditions: v (V) _d3 ≥18；

Abbe number V of the sixth lens _d6 The method meets the following conditions: v (V) _d6 ≤55。

10. The optical lens according to any one of claims 1 to 5, wherein,

refractive index N of the second lens _d2 The method meets the following conditions: n (N) _d2 ≤1.65；

Refractive index N of the fourth lens _d4 The method meets the following conditions: n (N) _d4 ≤1.93；

Refractive index N of the seventh lens _d7 The method meets the following conditions: n (N) _d7 ≤1.71。