WO2022205690A1 - Optical imaging lens - Google Patents

Abstract

The present invention provides an optical imaging lens, sequentially, from an object side to an imaging surface along an optical axis, comprising: a first lens having negative focal power, an object side surface thereof being a concave surface; a second lens having positive focal power, an object side surface thereof being a convex surface, and an image side surface thereof being a concave surface or approximately a flat surface; a third lens having positive focal power, an object side surface and an image side surface thereof being both convex surfaces; a fourth lens having positive focal power, an object side surface and an image side surface thereof being both convex surfaces; a fifth lens having negative focal power, an object side surface and an image side surface thereof being both concave surfaces, and the fourth lens and the fifth lens constituting a cemented lens group; a sixth lens having positive focal power, an object side surface thereof being a convex surface; a seventh lens having negative focal power, an object side surface and an image side surface thereof being both concave surfaces; and a diaphragm located between the first lens and the third lens. A focal length f of the optical imaging lens is greater than 12 mm. The optical imaging lens can realize long-distance high-definition imaging, also has the characteristics of large aperture, and can satisfy imaging requirements in a darker environment.

Description

Optical imaging lens

cross reference

This application claims the priority of an earlier application with the title of invention: "Optical Imaging Lens" filed on March 31, 2021, with application number 202110344658.4, the contents of the aforementioned earlier application are incorporated into this text by way of reference.

technical field

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

Background technique

Advanced Driver Assistance System (ADAS) mainly uses cameras to identify all-round conditions and road information on the outside of the vehicle, which can assist the driver in judging the road conditions, thereby helping the driver to make correct driving behaviors and reducing improper operations due to visual reasons. It makes the operation of the vehicle more stable, reliable and safe, and reduces the occurrence of accidents to a certain extent.

With the development of automobile intelligence, ADAS has become the standard configuration of automobiles, and cameras play a pivotal role in the application of ADAS. Through front-view, rear-view, and surround-view cameras, all-round information inside and outside the vehicle can be obtained. In order to meet the needs of automatic driving and other applications, under complex and changeable road conditions, it is necessary not only to pay attention to the close-range targets and road conditions in front of the vehicle, but also to the distant targets, especially the distance of 100 to 200 meters in front of the vehicle. Information; in order to obtain long-distance perception, the lens is required to have telephoto characteristics and the image should be clear within a small viewing angle range.

However, most of the small-angle lenses on the market generally have shortcomings such as low lens pixels and small lens apertures, which lead to poor recognition of long-distance targets and cannot meet the needs of ADAS.

SUMMARY OF THE INVENTION

Based on this, the purpose of the present invention is to provide an optical imaging lens with large aperture, small distortion and long focal length to meet the special imaging requirements in ADAS.

The embodiments of the present invention achieve the above objects through the following technical solutions.

The present invention provides an optical imaging lens, which sequentially includes:

a first lens with negative refractive power, the object side surface of the first lens is concave;

The second lens with positive refractive power, the object side of the second lens is convex, and the image side of the second lens is concave or plane;

a third lens with positive refractive power, the object side and the image side of the third lens are convex;

a fourth lens with positive refractive power, wherein both the object side and the image side of the fourth lens are convex;

a fifth lens with negative refractive power, the object side and the image side of the fifth lens are both concave, and the fourth lens and the fifth lens form a cemented lens group;

a sixth lens with positive refractive power, the object side surface of the sixth lens is convex;

The seventh lens with negative refractive power, the object side and the image side of the seventh lens are both concave;

and a diaphragm between the first lens and the third lens;

The lenses before the diaphragm form a first group, the lenses between the diaphragm and the fourth lens form a second group, the fourth lens, the fifth lens, the Six lenses and the seventh lens form a third group; the focal length of the optical imaging lens is f>12mm.

Compared with the prior art, the optical imaging lens provided by the present invention adopts seven lenses with a specific shape and refractive power, so that the optical imaging lens has a telephoto performance larger than 12 mm, and has the advantages of small distortion and high imaging quality, so that it can achieve Long-distance high-definition imaging, and the optical imaging lens also has the characteristics of large aperture, which can meet the imaging needs of dark environments.

Description of drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of embodiments taken in conjunction with the accompanying drawings, wherein:

1 is a schematic structural diagram of an optical imaging lens in a first embodiment of the present invention;

Fig. 2 is the f-θ distortion diagram of the optical imaging lens in the first embodiment of the present invention;

3 is an axial chromatic aberration diagram of the optical imaging lens in the first embodiment of the present invention;

4 is a schematic structural diagram of an optical imaging lens in a second embodiment of the present invention;

Fig. 5 is the f-θ distortion diagram of the optical imaging lens in the second embodiment of the present invention;

6 is an axial chromatic aberration diagram of an optical imaging lens in a second embodiment of the present invention;

7 is a schematic structural diagram of an optical imaging lens in a third embodiment of the present invention;

8 is an f-θ distortion diagram of an optical imaging lens in a third embodiment of the present invention;

9 is an axial chromatic aberration diagram of an optical imaging lens in a third embodiment of the present invention;

10 is a schematic structural diagram of an optical imaging lens in a fourth embodiment of the present invention;

FIG. 11 is an f-θ distortion diagram of the optical imaging lens in the fourth embodiment of the present invention;

12 is an axial chromatic aberration diagram of an optical imaging lens in a fourth embodiment of the present invention;

13 is a schematic structural diagram of an optical imaging lens in a fifth embodiment of the present invention;

14 is an f-θ distortion diagram of the optical imaging lens in the fifth embodiment of the present invention;

15 is an axial chromatic aberration diagram of an optical imaging lens in a fifth embodiment of the present invention;

16 is the defocus curve of the central field of view of the optical imaging lens at room temperature of 20°C in the first embodiment of the present invention;

17 is the defocus curve of the central field of view of the optical imaging lens at a high temperature of 125° C. in the first embodiment of the present invention;

18 is the defocus curve of the central field of view of the optical imaging lens at a low temperature of -40° C. in the first embodiment of the present invention;

FIG. 19 is a schematic diagram of the line of the edge rays of the central field of view provided by the present invention.

The following specific embodiments will further illustrate the present invention in conjunction with the above drawings.

Detailed ways

In order to make the objects, features and advantages of the present invention more clearly understood, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Several embodiments of the invention are shown in the drawings. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless otherwise defined, 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 invention belongs. The terms used in the description of the present invention are for the purpose of describing specific embodiments only, and are not intended to limit the present invention. Throughout the specification, the same reference numerals refer to the same elements.

The present invention provides an optical imaging lens with large aperture, small distortion and thermal compensation performance. The optical imaging lens includes sequentially from the object side to the imaging plane along the optical axis:

A first lens with negative refractive power, the object side of the first lens is concave, and the image side of the first lens is concave or convex;

The second lens with positive refractive power, the object side of the second lens is convex, and the image side of the second lens is concave or plane;

a third lens with positive refractive power, the object side and the image side of the third lens are convex;

a fourth lens with positive refractive power, wherein both the object side and the image side of the fourth lens are convex;

The fifth lens with negative refractive power, the object side and the image side of the fifth lens are concave, and the fourth lens and the fifth lens form a cemented lens group;

The sixth lens with positive refractive power, the object side of the sixth lens is convex, and the image side of the sixth lens is concave or convex;

The seventh lens with negative refractive power, the object side and the image side of the seventh lens are both concave;

and a diaphragm between the first lens and the third lens;

The lenses before the diaphragm form a first group, the lenses between the diaphragm and the fourth lens form a second group, the fourth lens, the fifth lens, the Six lenses and the seventh lens form a third group; the focal length of the optical imaging lens is f>12mm.

In some embodiments, the optical imaging lens satisfies the following conditional formula:

-100mm*℃＜f ₃ /(dn/dt) ₃ +f ₄ /(dn/dt) ₄ ＜-30mm*℃; (1)

Wherein, f ₃ represents the focal length of the third lens, f ₄ represents the focal length of the fourth lens, (dn/dt) ₃ represents the temperature index of refraction of the third lens, and (dn/dt) ₄ represents the the temperature index of refraction of the fourth lens.

Satisfying the above conditional formula (1), the third lens and the fourth lens are both positive lenses, and by controlling their temperature refractive index coefficients, the back focus shift and resolution reduction caused by temperature changes can be effectively compensated, and the back focus of the lens is deviated. The displacement is controlled within ±2μm, and the resolution drop is controlled within 8%, which effectively improves the temperature stability of the lens and enables the lens to maintain high resolution in high and low temperature environments.

In some embodiments, the first group has negative power, and the first group satisfies the following conditional formula:

-5.5mm/°<f _Q1 /ω _ST <0mm/°; (2)

Wherein, f _Q1 represents the focal length of the first group, ω _ST represents the incident angle of the marginal ray of the central field of view of the optical imaging lens at the diaphragm, and the schematic diagram of the line of the marginal ray of the central field of view can be seen in Figure 19 shown.

Satisfying the above conditional formula (2), by controlling the incident angle of the edge light entering the diaphragm, the aperture of the front end of the lens can be effectively reduced, and the pupil radius can be enlarged, so as to better realize the large aperture effect of the imaging system.

In some embodiments, the second lens is an aspheric lens, and the second lens satisfies the conditional expression:

0<f ₂ /R ₃ <5; (3)

Wherein, f ₂ represents the focal length of the second lens, and R ₃ represents the radius of curvature of the object side surface of the second lens.

Satisfying the above conditional expression (3), by reasonably controlling the non-curved surface shape and focal length of the second lens, the optical distortion of the lens can be effectively controlled, the degree of deformation of the photographed object can be reduced, and the imaging quality can be effectively improved.

In some embodiments, the first group satisfies the following conditional formula:

0<f _Q1 /R ₁ <5; (4)

Wherein, f _Q1 represents the focal length of the first group, and R ₁ represents the radius of curvature of the object side surface of the first lens.

Satisfying the above conditional formula (4) can effectively improve the relative illuminance of the lens. If the value of f _Q1 /R ₁ exceeds the upper limit, it will increase the difficulty of processing the lens and reduce the yield; if the value of f _Q1 /R ₁ exceeds the lower limit, As a result, the relative illumination of the imaging lens is too low, resulting in reduced edge brightness of the captured picture and even vignetting.

In some embodiments, the second group has positive refractive power, and the second group satisfies the following conditional formula:

0mm/°＜f _Q2 /ω _ex ＜4mm/°; (5)

Wherein, f _Q2 represents the focal length of the second group, and ω _ex represents the exit angle of the marginal field of view light on the image side of the third lens.

Satisfying the above conditional formula (5) can effectively reduce the angle between the exit light of the second group and the optical axis of the system, so that the light enters the third group at a smaller angle, which can effectively reduce the tolerance sensitivity of the third group degree, improve the assembly yield of the lens, and reduce the cost.

In some embodiments, the optical imaging lens satisfies the following conditional formula:

0.3<f ₃ /R ₆ +f ₄ /R ₇ <1; (6)

Wherein, f ₃ represents the focal length of the third lens, f ₄ represents the focal length of the fourth lens, R ₆ represents the curvature radius of the image side of the third lens, and R ₇ represents the object side of the fourth lens the radius of curvature.

Satisfying the above conditional formula (6) can effectively prevent the reflection light of the third group of lenses from generating ghost images on the image side of the third lens, reduce ghost images on the imaging surface, and effectively improve the imaging quality of the imaging lens.

In some embodiments, in order to effectively correct the field curvature of the imaging system, the optical imaging lens satisfies the following conditional formula:

-0.5<f ₆ /R ₁₀ -f ₇ /R ₁₂ <1; (7)

-2.5mm＜f ₆ /f ₇ *CT ₆₇ ＜-0.5mm; (8)

Wherein, f ₆ represents the focal length of the sixth lens, f ₇ represents the focal length of the seventh lens, R ₁₀ represents the radius of curvature of the object side of the sixth lens, and R ₁₂ represents the object side of the seventh lens The radius of curvature of CT ₆₇ represents the air space between the sixth lens and the seventh lens on the optical axis.

In some embodiments, the optical imaging lens satisfies the following conditional formula:

12mm<f<16mm;(9)

0.3 < f/TTL < 0.5; (10)

3mm ² /° < IH/θ*f < 4mm ² /°; (11)

Among them, f represents the focal length of the optical imaging lens, TTL represents the optical total length of the optical imaging lens, θ represents the half angle of view of the optical imaging lens, and IH represents the optical imaging lens at the corresponding half angle of view True image height at θ.

Satisfying the above conditional expressions (9) to (10) can ensure that the imaging lens has a sufficiently large focal length, which can increase the shooting distance of the imaging lens, so that the lens can shoot objects at a longer distance; (11), the imaging lens can have a larger imaging surface under a smaller field of view, so that the captured picture can contain more details, make the imaging clearer, and effectively improve the imaging of the imaging lens quality.

In some embodiments, the optical imaging lens satisfies the following conditional formula:

1 < D ₁ /D _ST <1.3; (12)

Wherein, D ₁ represents the effective aperture of the first lens, and D _ST represents the effective aperture of the diaphragm.

Satisfying the above conditional formula (12), the front end aperture of the imaging lens can be reduced, the volume of the lens can be reduced, the head of the lens can be extended forward, and the field of view can be prevented from being blocked by other components of the camera.

In some embodiments, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens in the optical imaging lens are all glass lenses.

In some embodiments, the second lens and the seventh lens in the optical imaging lens are glass aspherical lenses, and the first lens, the third lens, the fourth lens, the fifth lens, and the sixth lens are glass spherical lenses.

Satisfying the above configuration is beneficial to ensure that the optical imaging mirror has the performance of large aperture, small distortion and high pixel, and at the same time can improve the imaging capability of distant objects.

The surface shape of the aspheric surface of the optical imaging lens in each embodiment of the present invention satisfies the following equation:

Among them, z represents the distance of the surface from the vertex of the surface in the direction of the optical axis, c represents the curvature of the vertex of the surface, K represents the quadratic surface coefficient, h represents the distance from the optical axis to the surface, and B, C, D, E and F represent the four Order, sixth, eighth, tenth, and twelfth order surface coefficients.

In each of the following embodiments, the thickness, radius of curvature, and material selection of each lens in the optical imaging lens are different. For details, please refer to the parameter table of each embodiment.

first embodiment

Please refer to FIG. 1 , which is a schematic structural diagram of an optical imaging lens 100 provided by a first embodiment of the present invention. The optical imaging lens 100 sequentially includes a first lens L1 and a second lens L2 along the optical axis from the object side to the imaging plane. , diaphragm ST, third lens L3, fourth lens L4, fifth lens L5, sixth lens L6, seventh lens L7, and filter G1. The first lens L1 and the second lens L2 before the diaphragm ST form the first group Q1, the third lens L3 after the diaphragm ST forms the second group Q2, the fourth lens L4, the fifth lens L5, the sixth lens The lens L6 and the seventh lens L7 form the third group Q3.

The first lens L1 has negative refractive power, the object side S1 of the first lens is concave, the image side S2 of the first lens is close to a plane, and the first lens L1 is a glass spherical lens.

The second lens L2 has positive refractive power, the object side S3 of the second lens is convex, the image side S4 of the second lens is concave, and the second lens L2 is a glass aspheric lens.

The third lens L3 has positive refractive power, the object side S5 and the image side S6 of the third lens are both convex, and the third lens L3 is a glass spherical lens.

The fourth lens L4 has positive refractive power, and both the object side S7 and the image side S8 of the fourth lens are convex.

The fifth lens L5 has negative refractive power, the object side S8 and the image side S9 of the fifth lens are concave, and the fourth lens L4 and the fifth lens L5 are cemented into a cemented body and both are glass spherical lenses.

The sixth lens L6 has positive refractive power, the object side S10 and the image side S11 of the sixth lens are both convex surfaces, and the sixth lens L6 is a glass spherical lens.

The seventh lens L7 has negative refractive power, the object side S12 and the image side S13 of the seventh lens are both concave, and the seventh lens L7 is a glass aspheric lens.

The stop ST is provided between the second lens L2 and the third lens L3.

The relevant parameters of each lens in the optical imaging lens 100 provided in the first embodiment of the present invention are shown in Table 1-1.

Table 1-1

The parameters of the aspheric surfaces of each lens in this embodiment are shown in Table 1-2.

Table 1-2

face number	K	B	C	D	E	F
S3	-0.714863	-1.178903E-04	-3.020517E-06	-6.350180E-08	2.229938E-09	-3.356422E-11
S4	1.137224	-6.468669E-05	-3.309724E-06	-3.799668E-08	1.484592E-09	-1.539934E-11
S12	-4.214611	-1.339090E-03	8.671003E-05	-4.635435E-06	1.248815E-07	-1.102795E-09
S13	-14.999521	-6.945351E-04	6.555371E-05	-3.013417E-06	4.808847E-08	3.310120E-10

In this embodiment, the distortion curve and the axial chromatic aberration curve of the optical imaging lens 100 are shown in FIG. 2 and FIG. 3 , respectively. It can be seen from FIG. 2 that the f-θ distortion of the imaging system in this embodiment is within about 0.5% in the full field of view, which indicates that the optical imaging lens 100 hardly has the phenomenon of image plane curvature in the working field of view. It shows that the imaging lens has a high-definition resolution capability. It can be seen from FIG. 3 that the axial chromatic aberration of the single wavelength of the optical imaging lens 100 in this embodiment does not exceed 0.025mm at the maximum, and the difference between two different wavelengths does not exceed 0.03mm, indicating that the optical imaging lens 100 is in the pupil. Axial chromatic aberration at edge locations is well corrected.

Second Embodiment

Please refer to FIG. 4 , which is a structural diagram of an optical imaging lens 200 provided in this embodiment. The optical imaging lens 200 in this embodiment is almost the same as the optical imaging lens 100 in the first embodiment, the difference is that the aperture ST of the optical imaging lens 200 in this embodiment is set on the first lens L1 and the second lens L1 Between the lenses L2, the first lens L1 forms a first group Q1, the second lens L2 and the third lens L3 form a second group Q2, the image side S2 of the first lens is convex, and the image side S11 of the sixth lens L6 For the concave surface, and the curvature radius and material selection of each lens are different, the specific parameters of each lens are shown in Table 2-1.

table 2-1

The parameters of the aspheric surfaces of each lens in this embodiment are shown in Table 2-2.

Table 2-2

face number	K	B	C	D	E	F
S3	1.997293	-8.301004E-05	5.498105E-07	-6.842910E-08	2.026051E-09	-2.265804E-11
S4	-1.815196	-4.257695E-05	4.937647E-07	-5.007628E-08	1.416641E-09	-1.407558E-11
S12	24.058592	-3.462234E-03	1.914932E-04	-7.329618E-06	1.961727E-07	-2.544227E-09
S13	-6.660831	-2.962183E-03	1.929997E-04	-7.523448E-06	1.909195E-07	-2.270313E-09

In this embodiment, the distortion and axial chromatic aberration curves of the optical imaging lens 200 are shown in FIG. 5 and FIG. 6 , respectively. It can be seen from FIG. 5 that the f-θ distortion of the imaging system in this embodiment is within about 0.3% within the full field of view, indicating that the optical imaging lens 200 has a high-definition resolution capability. It can be seen from FIG. 6 that the axial chromatic aberration of the imaging lens of this embodiment does not exceed 0.015mm at the maximum, and the difference between two different wavelengths does not exceed 0.02mm, indicating that the optical imaging lens 200 is in the pupil Axial chromatic aberration at edge locations is well corrected.

Third Embodiment

Please refer to FIG. 7 , which is a structural diagram of an optical lens 300 provided in this embodiment. The optical lens 300 in this embodiment is almost the same as the optical lens 100 in the first embodiment, the difference is that the aperture ST of the optical lens 300 in this embodiment is set between the first lens L1 and the second lens L2 During the period, the first lens L1 forms the first group Q1, the second lens L2 and the third lens L3 form the second group Q2, the image side S2 of the first lens is concave, and the curvature radius and material selection of each lens are different, The specific parameters of each lens are shown in Table 3-1.

Table 3-1

The parameters of the aspheric surfaces of each lens in this embodiment are shown in Table 3-2.

Table 3-2

face number	K	B	C	D	E	F
S3	-1.040323	-1.597720E-04	-2.631015E-06	-7.156615E-08	2.324401E-09	-3.619454E-11
S4	1.345180	-8.569622E-05	-2.768056E-06	-2.675224E-08	1.361664E-09	-1.545814E-11
S12	-10.035001	-1.582207E-03	8.757697E-05	-4.538561E-06	1.415109E-07	-1.826832E-09
S13	10.319292	-6.946220E-04	5.725285E-05	-2.820924E-06	7.747309E-08	-7.892799E-10

In this embodiment, the distortion and axial chromatic aberration are shown in Fig. 8 and Fig. 9, respectively. It can be seen from FIG. 8 that the f-θ distortion of the imaging system in this embodiment is within about 1.5% in the full field of view, indicating that the optical imaging lens 300 has a high-definition resolution capability. It can be seen from FIG. 9 that the maximum axial chromatic aberration of the imaging lens of this embodiment does not exceed 0.025mm, and the difference between two different wavelengths does not exceed 0.025mm, indicating that the optical imaging lens 300 is in the light Axial chromatic aberration at the pupil edge is well corrected.

Fourth Embodiment

Please refer to FIG. 10 , which is a structural diagram of an optical lens 400 provided in this embodiment. The optical lens 400 in this embodiment is almost the same as the optical lens 100 in the first embodiment, the difference is that the aperture ST of the optical lens 400 in this embodiment is set on the first lens L1 and the second lens L2 In between, the first lens L1 forms the first group Q1, the second lens L2 and the third lens L3 form the second group Q2, the image side S2 of the first lens is concave, and the image side S11 of the sixth lens L6 is concave , and the curvature radius and material selection of each lens are different, and the specific parameters of each lens are shown in Table 4-1.

Table 4-1

The parameters of the aspheric surfaces of each lens in this embodiment are shown in Table 4-2.

Table 4-2

face number	K	B	C	D	E	F
S3	3.242254	-1.595936E-04	2.697353E-07	-1.142137E-07	3.465617E-09	-4.865593E-11
S4	-10.001592	-5.436967E-05	-1.161570E-07	-4.720677E-08	1.072165E-09	-1.263428E-11
S12	-6.685339	-3.760563E-03	2.309372E-04	-8.330686E-06	1.814772E-07	-1.821290E-09
S13	-69.507143	-2.379739E-03	1.775943E-04	-6.225683E-06	1.339508E-07	-1.294897E-09

In this embodiment, the distortion and axial chromatic aberration are shown in Fig. 11 and Fig. 12, respectively. It can be seen from FIG. 11 that the f-θ distortion of the imaging system in this embodiment is within about 0.5% in the full field of view, indicating that the optical imaging lens 400 has a high-definition resolution capability. It can be seen from FIG. 12 that the axial chromatic aberration of the imaging lens of this embodiment does not exceed 0.025mm at the maximum, and the difference between two different wavelengths does not exceed 0.025mm, indicating that the optical imaging lens 400 is in the light Axial chromatic aberration at the pupil edge is well corrected.

Fifth Embodiment

Please refer to FIG. 13 , which is a structural diagram of an optical lens 500 provided in this embodiment. The optical lens 500 in this embodiment is almost the same as the optical lens 100 in the first embodiment, the difference is that the aperture ST of the optical lens 500 in this embodiment is set on the first lens L1 and the second lens L2 In between, the first lens L1 forms a first group Q1, the second lens L2 and the third lens L3 form a second group Q2, the image side S2 of the first lens is concave, and the image side S11 of the sixth lens L6 is concave , and the curvature radius and material selection of each lens are different. For the specific parameters of each lens, see Table 5-1.

Table 5-1

The parameters of the aspheric surfaces of each lens in this embodiment are shown in Table 5-2.

Table 5-2

face number	K	B	C	D	E	F
S3	3.231939	-1.482878E-04	3.934072E-07	-1.151156E-07	3.255295E-09	-4.366234E-11
S4	-7.337148	-3.191155E-05	1.416256E-07	-5.613034E-08	1.292408E-09	-1.553197E-11
S12	-14.241221	-3.580900E-03	2.155208E-04	-7.869861E-06	1.730498E-07	-1.723354E-09

S13

-70.737874

-2.093186E-03

1.543630E-04

-5.300561E-06

1.072223E-07

-9.327477E-10

In this embodiment, the distortion and axial chromatic aberration are shown in Figure 14 and Figure 15, respectively. It can be seen from FIG. 14 that the f-θ distortion of the imaging system in this embodiment is within -0.3% in the full field of view, indicating that the optical imaging lens 500 has a high-definition resolution capability. It can be seen from FIG. 15 that the maximum axial chromatic aberration of the imaging lens of this embodiment does not exceed 0.025mm, and the difference between two different wavelengths does not exceed 0.025mm, indicating that the optical imaging lens 500 is in the light Axial chromatic aberration at the pupil edge is well corrected.

Table 6 is the above-mentioned five embodiments and their corresponding optical characteristics, including the field angle 2θ, the aperture number F#, and the total optical length TTL, as well as the values corresponding to each of the preceding conditional expressions.

Table 6

conditional	Example 1	Example 2	Example 3	Example 4	Example 5
2θ(°)	40	42	40	44	42
F#	1.6	1.6	1.6	1.6	1.6
TTL(mm)	28.8	32	29	31.5	31.5
f(mm)	13.942	14.440	13.906	14.609	14.832
f 3 /(dn/dt) 3 +f 4 /(dn/dt) 4	-56.128	-59.408	-51.902	-72.212	-75.356
f Q1 /ω ST	-3.576	-4.922	-3.055	-1.268	-1.142
f 2 /R 3	2.608	4.453	2.916	1.225	1.195
f Q1 /R 1	4.069	2.388	1.389	1.134	1.123
f Q2 /ω ex	3.335	2.986	1.578	2.791	2.997
f 3 /R 6 +f 4 /R 7	0.489	0.815	0.788	0.747	0.788
f6 /R10 - f7 / R12	-0.358	0.849	-0.401	0.457	0.384
f 6 /f 7 *CT 67	-0.986	-1.162	-1.128	-1.914	-1.876
f/TTL	0.484	0.451	0.480	0.464	0.471
IH/θ*f	3.410	3.647	3.412	3.750	3.839
D 1 /D ST	1.127	1.069	1.078	1.050	1.040

Further, the optical imaging lens provided by the embodiments of the present invention can effectively correct the problems of optical back focus shift and resolution reduction caused by temperature changes. Taking the optical imaging lens 100 provided by the first embodiment as an example, as shown in FIG. 16 , FIG. 17 , and FIG. 18 , the optical imaging lens 100 provided by the first embodiment of the present invention has a temperature of 20° C. and a high temperature of 125° C. respectively. As well as the defocus curve of the central field of view at a low temperature of -40°C, it can be seen from the figure that: based on the normal temperature of 20°C, when the optical imaging lens 100 is at a high temperature of 125°C, the back focus shift of the imaging system is about is +2.0μm, the MTF drop is less than 3.5%; when the low temperature is -40°C, the back focus shift of the imaging system is about -1.5μm, and the MTF drop is less than 3.0%. The optical imaging lenses provided in other embodiments have smaller back focus shifts and MTF drops under high and low temperature conditions. It can be seen that the optical imaging lenses can well correct the back focus caused by temperature. offset, and the MTF drop is small, which effectively ensures the imaging quality of the lens in high and low temperature environments, and greatly improves the thermal stability of the lens.

To sum up, in the optical imaging lens provided by the present invention, the first group Q1 has a negative refractive power, which can effectively reduce the diameter of the front end of the lens, and can expand the pupil radius to realize the large-aperture imaging effect of the imaging system; By controlling the curvature radius of the object side surface of the first lens L1, the relative illuminance of the imaging lens can be effectively improved; the second lens L2 is an aspherical lens, which is mainly used for correcting distortion; the third lens L3 and the fourth lens L4 both have A lens with positive refractive power and a lens with a specific temperature index of refraction are selected, and the focal length of the third lens L3 and the fourth lens L4 can effectively compensate for thermal drift; and the third lens L3 can effectively reduce the outgoing light. The fourth lens L4 and the fifth lens L5 form a cemented body, and the Abbe number Vd difference of the positive and negative lenses is greater than 40, which can effectively correct the chromatic aberration; the sixth lens L6 and the seventh lens L7 cooperate with each other to effectively correct the field curvature; the seventh lens L7 is an aspherical lens, which can eliminate aberrations and control the exit angle of the chief ray, effectively improve the resolution of the imaging system, and make the imaging system Meet higher pixel requirements. Each lens is a glass lens, so that the lens has good thermal stability and mechanical strength, which is beneficial to work in extreme environments. Each lens is a glass lens, so that the lens has good thermal stability and mechanical strength, which is beneficial to work in extreme environments.

The above-mentioned embodiments only represent several embodiments of the present invention, and the descriptions thereof are specific and detailed, but should not be construed as a limitation on the scope of the patent of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can also be made, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention should be subject to the appended claims.

Claims (11)

1. An optical imaging lens, characterized in that, from the object side to the imaging plane along the optical axis, it comprises:

   a first lens with negative refractive power, the object side surface of the first lens is concave;

   The second lens with positive refractive power, the object side of the second lens is convex, and the image side of the second lens is concave or plane;

   a third lens with positive refractive power, the object side and the image side of the third lens are convex;

   a fourth lens with positive refractive power, wherein both the object side and the image side of the fourth lens are convex;

   a fifth lens with negative refractive power, the object side and the image side of the fifth lens are both concave, and the fourth lens and the fifth lens form a cemented lens group;

   a sixth lens with positive refractive power, the object side surface of the sixth lens is convex;

   The seventh lens with negative refractive power, the object side and the image side of the seventh lens are both concave;

   and a diaphragm between the first lens and the third lens;

   The lenses before the diaphragm form a first group, the lenses between the diaphragm and the fourth lens form a second group, the fourth lens, the fifth lens, the Six lenses and the seventh lens form a third group;

   The focal length of the optical imaging lens is f>12mm.
2. The optical imaging lens according to claim 1, wherein the optical imaging lens satisfies the following conditional formula:

   -100mm*℃＜f ₃ /(dn/dt) ₃ +f ₄ /(dn/dt) ₄ ＜-30mm*℃;

   Wherein, f ₃ represents the focal length of the third lens, f ₄ represents the focal length of the fourth lens, (dn/dt) ₃ represents the temperature index of refraction of the third lens, and (dn/dt) ₄ represents the the temperature index of refraction of the fourth lens.
3. The optical imaging lens according to claim 1, wherein the first group has negative refractive power, and the first group satisfies the following conditional formula:

   -5.5mm/°＜f _Q1 /ω _ST ＜0mm/°;

   Wherein, f _Q1 represents the focal length of the first group, and ω _ST represents the incident angle of the marginal ray of the central field of view of the optical imaging lens at the diaphragm.
4. The optical imaging lens according to claim 1, wherein the second lens is an aspherical lens, and the second lens satisfies the following conditional formula:

   0<f ₂ /R ₃ <5;

   Wherein, f ₂ represents the focal length of the second lens, and R ₃ represents the radius of curvature of the object side surface of the second lens.
5. The optical imaging lens according to claim 1, wherein the first group satisfies the following conditional formula:

   0<f _Q1 /R ₁ <5;

   Wherein, f _Q1 represents the focal length of the first group, and R ₁ represents the curvature radius of the object side surface of the first lens.
6. The optical imaging lens according to claim 1, wherein the second group has positive refractive power, and the second group satisfies the following conditional formula:

   0mm/°＜f _Q2 /ω _ex ＜4mm/°;

   Wherein, f _Q2 represents the focal length of the second group, and ω _ex represents the exit angle of the marginal field of view light on the image side of the third lens.
7. The optical imaging lens according to claim 1, wherein the optical imaging lens satisfies the following conditional formula:

   0.3<f ₃ /R ₆ +f ₄ /R ₇ <1;

   Wherein, f ₃ represents the focal length of the third lens, f ₄ represents the focal length of the fourth lens, R ₆ represents the curvature radius of the image side of the third lens, and R ₇ represents the object side of the fourth lens the radius of curvature.
8. The optical imaging lens according to claim 1, wherein the optical imaging lens satisfies the following conditional formula:

   -0.5<f ₆ /R ₁₀ -f ₇ /R ₁₂ <1;

   -2.5mm＜f ₆ /f ₇ *CT ₆₇ ＜-0.5mm;

   Wherein, f ₆ represents the focal length of the sixth lens, f ₇ represents the focal length of the seventh lens, R ₁₀ represents the radius of curvature of the object side of the sixth lens, and R ₁₂ represents the object side of the seventh lens The radius of curvature of CT ₆₇ represents the air space between the sixth lens and the seventh lens on the optical axis.
9. The optical imaging lens according to claim 1, wherein the optical imaging lens satisfies the following conditional formula:

   12mm<f<16mm;

   0.3<f/TTL<0.5;

   3mm ² /°<IH/θ*f<4mm ² /°;

   Among them, f represents the focal length of the optical imaging lens, TTL represents the optical total length of the optical imaging lens, θ represents the half angle of view of the optical imaging lens, and IH represents the optical imaging lens at the corresponding half angle of view True image height at θ.
10. The optical imaging lens according to claim 1, wherein the optical imaging lens satisfies the following conditional formula:

    1 < D ₁ /D _ST <1.3;

    Wherein, D ₁ represents the effective aperture of the first lens, and D _ST represents the effective aperture of the diaphragm.
11. The optical imaging lens according to claim 1, wherein the second lens and the seventh lens are glass aspherical lenses, the first lens, the third lens, the fourth lens, Both the fifth lens and the sixth lens are glass spherical lenses.

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