CN111273429A - Optical imaging system - Google Patents

Abstract

The invention discloses an optical imaging system. The optical imaging system is a seven-piece aspherical structure, comprising a first lens, a second lens, a third lens, a fourth lens, and a third lens arranged in sequence from the object side to the image side Five lens, sixth lens, seventh lens, infrared filter and image sensor, the first lens has positive power, the second lens has negative power, the third lens has positive power, the fourth lens has power, and the fifth lens has power , The object-side surface of the fifth lens is a recurve shape, the center part is convex toward the object surface, and the edge parts of the fifth lens are all curved in the direction of the object surface, and its shape is the Arabic numeral "3", the sixth lens has a diopter, The seventh lens has a diopter, and the optical imaging system can well solve the stray light problem, greatly reduce the tolerance sensitivity of the camera module face error, eccentricity, concentricity and inclination error, and improve the camera module yield.

Description

an optical imaging system

technical field

The present invention relates to an optical imaging system, and in particular to a miniaturized optical imaging system applied to electronic products.

Background technique

At present, the newly launched smartphones have been continuously upgraded on the rear camera. In just a few years, the mobile phone camera is going from 6M→8M→13M→16M→24M→48M→64M→108M, and the rear pixels are almost showing a trend of upgrading every year. It is known from the supply chain channels of the camera industry that some well-known mobile phone manufacturers have planned to include 216M pixels on the development agenda in the next two years. Various mobile phone manufacturers have won the market by continuously upgrading the camera pixels and increasing the camera functions.

In order to obtain the continuous upgrade of the pixels of the mobile phone camera, a major change in the current mobile phone camera technology is to use the larger size CMOS used in the digital camera to improve the picture quality. 1/1.7-inch CMOS is now the new choice for mobile phone camera sensors. And more mobile phones also use 1/2.3-inch sensors. The sensors used in these traditional card DC cameras have become the choice of a new generation of camera phones. Obviously, mobile phones have begun to eliminate traditional digital cameras from the hardware parameters.

Due to the continuous increase in the number of pixels and resolution requirements, the top specifications of all smartphone cameras with more than 20 million pixels are generally six-piece aspherical lens mobile phone cameras, and six-piece aspherical lens mobile phone cameras have been used for many years. , but it can generally only be used for mobile phone cameras below 24M, and mobile phone cameras with higher pixels are difficult to meet the requirements due to the size of the sensor panel and the increase of the field of view, which requires the use of seven-piece aspherical lenses. of mobile phone cameras or more plastic aspherical mobile phone cameras. With the expansion of the application of mobile phone cameras with multiple lenses and seven-piece aspherical lenses, the new demand for cameras will be detonated by smartphones in the future.

At present, various well-known mobile phone manufacturers have three-lens or multi-lens solutions, and are also discussing the introduction of seven-piece aspherical lenses for mobile phone cameras. Among the three lenses, each single lens has a very high specification. In the future, the three lenses may also see one or two seven-piece aspherical lens mobile phone cameras.

As far as mobile phone cameras with seven-piece aspherical lenses are concerned, they have higher specifications and can achieve better imaging quality. huge challenge. The first is the mobile phone camera with seven-piece aspherical lens. Since each piece is a plastic aspherical surface, the requirements for the surface error, concentricity, inclination and assembly error of the lens are very strict. The first is the surface error and Yass of the lens. Generally, it is required to be within 1 Newton ring (that is, the surface error is about 0.3 microns). The assembly error between the lens itself and the lens is generally required to be within 2 microns. The concentricity of the surface and the concentricity between the lenses are also required to be within 1 micron, so as to ensure a clear image on the sensor. At the same time, due to the use of seven plastic aspheric surfaces, the overall transmittance of the mobile phone camera is also reduced a lot, generally not more than 70%; Partial reflections have also increased, and the problem of stray light or ghosting will be more serious than the previous six- and five-piece cameras, which requires that each lens of the camera must be coated with an anti-reflection coating to improve transmittance and stray light. The problem.

In recent years, the design of seven-piece mobile phone camera has appeared, such as the patent TW201403166A in Taiwan, which solves the problems of large field of view (field of view greater than 80 degrees) and large panel sensor, and can obtain clear imaging. However, these structures also have some problems. The center of the second surface 162 of the sixth lens 160 is too convex, and the thickness of the center of the lens exceeds twice the thickness of the edge of the lens, which will cause the surface 162 to have surface errors, eccentricity, and concentricity. degrees, and inclination errors are very sensitive. In addition, the uneven thickness of the lens can easily lead to the Yass phenomenon of uneven surface error in the XY direction during the injection and demolding process of the lens, resulting in blurring and ghosting when the camera takes pictures, reducing the camera's yield rate. A major problem is that the partial reflection of the protruding part in the middle of the second surface 162 of the sixth lens 160 will lead to stray light and ghost images. Under the condition of strong light irradiation, the position within the 0.707 field of view of the image surface is prone to irreversible. The only way to solve the problem of stray light is to coat the surface of the lens with an anti-reflection film with high transmittance to improve the problem of stray light to a certain extent.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the above-mentioned defects in the prior art, and to provide an optical imaging system that can well solve the problem of stray light, and greatly reduces the tolerance sensitivity of the camera module to the surface error, eccentricity, concentricity and inclination error. to improve the yield rate of camera modules.

In order to achieve the above purpose, the present invention provides an optical imaging system, the optical imaging system is a seven-piece aspheric structure, including a first lens, a second lens, a third lens, The fourth lens, the fifth lens, the sixth lens, the seventh lens, the infrared filter and the image sensor, the first lens, which has a positive refractive power, the second lens, which has a negative refractive power, the third lens , which has a positive power, the fourth lens, which has a power, the fifth lens, which has a power, the fifth lens has a fifth lens object side surface and a fifth lens image side surface, the fifth lens The object-side surface of the lens is in a retrocurved shape, the center part is convex toward the object plane, the area between the center part and the edge part is curved toward the image plane, and the edge parts of the fifth lens are all curved toward the object plane, which The shape is an Arabic numeral "3", the sixth lens has a diopter, the sixth lens has a sixth lens object side surface and a sixth lens image side surface, and the center part of the sixth lens object side surface faces the object The surface direction is convex, the center part of the image side surface of the sixth lens is convex toward the image plane, the seventh lens has a diopter, and the seventh lens has a seventh lens object side surface and a seventh lens image side The center part of the object-side surface of the seventh lens is concave toward the interior of the lens, and the center part of the image-side surface of the seventh lens is concave toward the interior of the lens.

Preferably, the ratio of the edge thickness to the center thickness of the fourth lens, the fifth lens and the sixth lens is: 0.2<DT/DC<4.

Preferably, the range of the combined focal length of the optical imaging system is: 3.65mm<f<7.5mm, and the diagonal dimension of the image plane is greater than 6.4mm.

所述第一镜片为低折射率、高色散系数的光学材料构件，其折射率nd＜1.58，其色散系数vd ＞50。Preferably, the first lens has a first lens object side surface and a first lens image side surface, both the first lens object side surface and the first lens image side surface are curved toward the image plane, the first lens The ratio of the focal length f1 of the lens to the combined focal length f of the optical imaging system is

The first lens is an optical material component with low refractive index and high dispersion coefficient, the refractive index nd<1.58, and the dispersion coefficient vd >50.

所述第二镜片为高折射率、低色散系数的光学材料构件，其折射率nd＞1.6，其色散系数vd＜ 30。Preferably, the center thickness of the second lens is thinner than the edge thickness, and the ratio of the focal length f2 of the second lens to the combined focal length f of the optical imaging system is

The second lens is an optical material component with high refractive index and low dispersion coefficient, the refractive index nd>1.6, and the dispersion coefficient vd<30.

所述第三镜片为低折射率、高色散系数的光学材料构件，其折射率nd＜1.58，其色散系数vd＞50。Preferably, the ratio of the focal length f3 of the third lens to the combined focal length f of the optical imaging system is

The third lens is an optical material component with a low refractive index and a high dispersion coefficient, the refractive index nd<1.58, and the dispersion coefficient vd>50.

所述第四镜片为高折射率、低色散系数的光学材料构件，其折射率nd＞1.6，其色散系数vd＜30。Preferably, the fourth lens has an object-side surface of the fourth lens and an image-side surface of the fourth lens, the object-side surface of the fourth lens is curved toward the object plane, and the focal length f4 of the fourth lens is related to the optical imaging system The ratio of the combined focal length f is

The fourth lens is an optical material component with high refractive index and low dispersion coefficient, the refractive index nd>1.6, and the dispersion coefficient vd<30.

其曲率半径R₂₅₁与光学成像系统的组合焦距f的比值为

所述第五镜片的焦距f5与光学成像系统的组合焦距f的比值为

Preferably, the fifth lens has an object-side surface of the fifth lens and an image-side surface of the fifth lens, the curved surface design of the object-side surface of the fifth lens is relatively gentle, and the ratio of the sagittal height to the optical clear aperture is less than 0.2, which is

The ratio of its curvature radius R ₂₅₁ to the combined focal length f of the optical imaging system is

The ratio of the focal length f5 of the fifth lens to the combined focal length f of the optical imaging system is

Preferably, the ratio of the focal length f6 of the sixth lens to the combined focal length f of the optical imaging system is

和

Preferably, the seventh lens is thinner in the middle, gradually thickens from the center to the edge, and then becomes thinner again, the ratio of the thickest to the thinnest part of the seventh lens is less than 3, and the seventh lens is Both the lateral surface and the image side surface of the seventh lens are relatively flat, and the ratio of the sagittal height to the aperture is less than 0.2, that is,

and

Compared with the prior art, the beneficial effects of the present invention are:

The present invention is provided with an optical imaging system, the optical imaging system is a seven-piece aspheric structure, and includes a first lens, a second lens, a third lens, a fourth lens, and a fifth lens arranged in sequence from the object side to the image side , a sixth lens, a seventh lens, an infrared filter and an image sensor, the first lens, which has a positive refractive power, the second lens, which has a negative refractive power, the third lens, which has a positive refractive power, the the fourth lens has a diopter, the fifth lens has a diopter, the fifth lens has a fifth lens object side surface and a fifth lens image side surface, the fifth lens object side surface is recurve Shape, the center part is convex toward the object plane, the area between the center part and the edge part is curved toward the image plane direction, the edge parts of the fifth lens are all curved toward the object plane direction, and its shape is the Arabic numeral "3" , the sixth lens has a diopter, the sixth lens has an object side surface of the sixth lens and an image side surface of the sixth lens, the center part of the object side surface of the sixth lens is convex toward the object surface, the The center part of the image side surface of the sixth lens is convex toward the image plane, the seventh lens has a diopter, the seventh lens has the seventh lens object side surface and the seventh lens image side surface, the seventh lens The center part of the object-side surface of the lens is concave to the inside of the lens, and the center part of the image-side surface of the seventh lens is concave to the interior of the lens. The optical imaging system designs the fifth lens to be a recurve shape, which can share a part of the diopter of the sixth lens , so that the sixth lens can be thinned, and the optical imaging system can control the ratio of the edge thickness to the center thickness of the fourth lens, the fifth lens and the sixth lens to be within 0.5<DT/DC<2. The thickness ratio of the seventh lens is controlled, and the image surface curvature problem caused by the large sensor size can be improved. The optical imaging system can solve the stray light problem well, and greatly reduce the camera module's face-to-face error, eccentricity, and concentricity. Tolerance sensitivity of inclination and inclination errors to improve the yield of camera modules.

Description of drawings

In order to illustrate the embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are For some embodiments of the present invention, for those of ordinary skill in the art, other drawings can also be obtained according to these drawings without creative efforts.

Fig. 1 is a sectional view of a seven-piece optical imaging system proposed by patent TW201403166A;

2 is a cross-sectional view of an optical imaging system according to an embodiment of the present invention;

3 is a cross-sectional view of a first lens of an optical imaging system according to an embodiment of the present invention;

4 is a cross-sectional view of a second lens of an optical imaging system according to an embodiment of the present invention;

5 is a cross-sectional view of a third lens of an optical imaging system according to an embodiment of the present invention;

6 is a cross-sectional view of a fourth lens of an optical imaging system according to an embodiment of the present invention;

7 is a cross-sectional view of a fifth lens of an optical imaging system according to an embodiment of the present invention;

8 is a cross-sectional view of a sixth lens of an optical imaging system according to an embodiment of the present invention;

9 is a cross-sectional view of a seventh lens of an optical imaging system according to an embodiment of the present invention;

10 is an optical path diagram of an optical imaging system according to an embodiment of the present invention;

11 is a modulation transfer function MTF curve of an optical imaging system according to an embodiment of the present invention;

12 is an MTF-depth of focus curve of an optical imaging system according to an embodiment of the present invention;

13 is a dot diagram of an optical imaging system according to an embodiment of the present invention;

14 is the field curvature and F-Tan(θ) distortion of an optical imaging system according to an embodiment of the present invention;

15 is a cross-sectional view of an optical imaging system according to Embodiment 2 of the present invention;

16 is a cross-sectional view of a first lens of an optical imaging system according to the second embodiment of the present invention;

17 is a cross-sectional view of a second lens of an optical imaging system according to the second embodiment of the present invention;

18 is a cross-sectional view of a third lens of an optical imaging system according to the second embodiment of the present invention;

19 is a cross-sectional view of a fourth lens of an optical imaging system according to the second embodiment of the present invention;

20 is a cross-sectional view of a fifth lens of an optical imaging system according to the second embodiment of the present invention;

21 is a cross-sectional view of a sixth lens of an optical imaging system according to Embodiment 2 of the present invention;

22 is a cross-sectional view of a seventh lens of an optical imaging system according to Embodiment 2 of the present invention;

23 is an optical path diagram of an optical imaging system according to Embodiment 2 of the present invention;

24 is a dot diagram of an optical imaging system according to the second embodiment of the present invention;

25 is the field curvature and F-Tan(θ) distortion of an optical imaging system according to the second embodiment of the present invention;

26 is a cross-sectional view of an optical imaging system according to Embodiment 3 of the present invention;

27 is a cross-sectional view of a first lens of an optical imaging system according to Embodiment 3 of the present invention;

28 is a cross-sectional view of the second lens and the third lens of an optical imaging system according to Embodiment 3 of the present invention;

29 is a cross-sectional view of a fourth lens of an optical imaging system according to Embodiment 3 of the present invention;

30 is a cross-sectional view of a fifth lens of an optical imaging system according to Embodiment 3 of the present invention;

31 is a cross-sectional view of a sixth lens of an optical imaging system according to Embodiment 3 of the present invention;

32 is a cross-sectional view of a seventh lens of an optical imaging system according to Embodiment 3 of the present invention;

33 is an optical path diagram of an optical imaging system according to Embodiment 3 of the present invention;

34 is a dot diagram of an optical imaging system according to Embodiment 3 of the present invention;

FIG. 35 is the field curvature and F-Tan(θ) distortion of an optical imaging system according to the third embodiment of the present invention.

Included in the diagram are:

2-optical imaging system, 21-first lens, 22-second lens, 23-third lens, 24-fourth lens, 25-fifth lens, 26-sixth lens, 27-seventh lens, 28- Infrared filter, 29-image sensor, 211-first lens object side surface, 212-first lens image side surface, 221-second lens object side surface, 222-second lens image side surface, 231-third lens Object side surface, 232-image side surface of third lens, 241-object side surface of fourth lens, 242-image side surface of fourth lens, 251-object side surface of fifth lens, 252-image side surface of fifth lens, 261 - Object side surface of sixth lens, 262 - Image side surface of sixth lens, 271 - Object side surface of seventh lens, 272 - Image side surface of seventh lens, 281 - Object side surface of infrared filter, 282 - Image of infrared filter Lateral surface, 291-image plane.

Detailed ways

The technical solutions in this embodiment of the present invention will be clearly and completely described below with reference to the accompanying drawings in the present embodiment of the present invention. Obviously, the described embodiment is an embodiment of the present invention, not all of them. this embodiment. Based on the present embodiment of the present invention, all other embodiments of the present invention obtained by those of ordinary skill in the art without making creative efforts partially belong to the protection scope of the present invention.

Example 1

Referring to FIGS. 2 to 9 , the first embodiment provides an optical imaging system. The optical imaging system 2 is a seven-piece aspherical structure, including a first lens 21 , a first lens 21 , a The second lens 22, the third lens 23, the fourth lens 24, the fifth lens 25, the sixth lens 26, the seventh lens 27, the infrared filter 28 and the image sensor 29, the aperture stop of which is located on the object side surface 211 of the first lens superior.

The range of the combined focal length of the optical imaging system 2 is: 3.65mm<f<7.5mm, and the diagonal size of the image plane is greater than 6.4mm. In the first embodiment, the combined focal length of the optical imaging system 2 is preferably: f =3.827817451978569 mm.

所述第一镜片21为低折射率、高色散系数的光学材料构件，其折射率nd＜1.58，其色散系数vd ＞50。The cross-sectional view of the first lens 21 is shown in FIG. 3, which has a positive refractive power, the first lens 21 has a first lens object side surface 211 and a first lens image side surface 212, the first lens object side surface 211 and the image-side surface 212 of the first lens are both curved toward the image plane, and the ratio of the focal length f1 of the first lens 21 to the combined focal length f of the optical imaging system 2 is

The first lens 21 is an optical material component with a low refractive index and a high dispersion coefficient, the refractive index nd<1.58, and the dispersion coefficient vd >50.

所述第二镜片22为高折射率、低色散系数的光学材料构件，其折射率nd＞1.6，其色散系数vd ＜30。The cross-sectional view of the second lens 22 is shown in FIG. 4, which has a negative diopter, the center thickness of the second lens 22 is thinner than the edge thickness, the second lens 22 has a second lens object side surface 221 and a second lens The lens image side surface 222, the second lens object side surface 221 has a slight inflection, the center portion of the second lens object side surface 221 is curved toward the image plane, and the edge portion is slightly curved toward the object side direction; The image-side surface 222 of the second lens is curved toward the image plane, and the ratio of the focal length f2 of the second lens 22 to the combined focal length f of the optical imaging system 2 is

The second lens 22 is an optical material member with a high refractive index and a low dispersion coefficient, the refractive index nd>1.6, and the dispersion coefficient vd <30.

所述第三镜片23为低折射率、高色散系数的光学材料构件，其折射率nd＜ 1.58，其色散系数vd＞50。The cross-sectional view of the third lens 23 is shown in FIG. 5, which has a positive refractive power, the third lens 23 has a third lens object side surface 231 and a third lens image side surface 232, the third lens object side surface 231 is curved toward the image plane, the image-side surface 232 of the third lens is curved toward the object plane, and the ratio of the focal length f3 of the third lens 23 to the combined focal length f of the optical imaging system 2 is

The third lens 23 is an optical material component with a low refractive index and a high dispersion coefficient, the refractive index nd<1.58, and the dispersion coefficient vd>50.

所述第四镜片24为高折射率、低色散系数的光学材料构件，其折射率nd＞1.6，其色散系数vd＜30。A cross-sectional view of the fourth lens 24 is shown in FIG. 6, which has a diopter, the fourth lens 24 has a fourth lens object side surface 241 and a fourth lens image side surface 242, the fourth lens object side surface 241 and the image-side surface 242 of the fourth lens are both curved toward the object plane, and the ratio of the focal length f4 of the fourth lens 24 to the combined focal length f of the optical imaging system 2 is

The fourth lens 24 is an optical material member with a high refractive index and a low dispersion coefficient, the refractive index nd>1.6, and the dispersion coefficient vd<30.

所述第五镜片物侧表面251，其曲率半径R₂₅₁与光学成像系统2的组合焦距f的比值为

所述第五镜片25的焦距f5与光学成像系统2的组合焦距f 的比值为

The cross-sectional view of the fifth lens 25 is shown in FIG. 7, which has a diopter, the fifth lens 25 has a fifth lens object side surface 251 and a fifth lens image side surface 252, and the fifth lens object side surface 251 It is a recurved shape, the center part is convex toward the object plane, the area between the center part and the edge part is curved toward the image plane, and the edge parts of the object side surface 251 of the fifth lens and the image side surface 252 of the fifth lens, They are all curved in the direction of the object plane, and their shape is an Arabic numeral "3". Through the inverse curvature design of the fifth lens 25, it can share a part of the diopter of the sixth lens 26, so that the thickness of the sixth lens 26 can be adjusted. In the thinning design, the curved surface design of the object-side surface 251 of the fifth lens is relatively gentle, and the ratio of the sag to the optical clear aperture is less than 0.2, that is,

The ratio of the curvature radius R ₂₅₁ of the object-side surface 251 of the fifth lens to the combined focal length f of the optical imaging system 2 is

The ratio of the focal length f5 of the fifth lens 25 to the combined focal length f of the optical imaging system 2 is

A cross-sectional view of the sixth lens 26 is shown in FIG. 8, which has a diopter, the sixth lens 26 has a sixth lens object side surface 261 and a sixth lens image side surface 262, the sixth lens object side surface 261 It has a slightly recurve shape, its central part is curved toward the image plane, convex toward the object plane, and the edge portion is curved toward the object plane. The image side surface 262 of the sixth lens is curved toward the object plane, toward the image plane. The direction is convex, and the ratio of the focal length f6 of the sixth lens 26 to the combined focal length f of the optical imaging system 2 is

和

The cross-sectional view of the seventh lens 27 is shown in FIG. 9 , which has diopter. The seventh lens 27 is thinner in the middle, gradually thickens from the center to the edge, and then becomes thinner again. The ratio of the thickness to the thinnest part is less than 3, the seventh lens 27 has a seventh lens object side surface 271 and a seventh lens image side surface 272, and the center part of the seventh lens object side surface 271 is curved toward the object plane , concave to the inside of the lens, and the edge portion is curved toward the image plane. The center portion of the image side surface 272 of the seventh lens is curved toward the image plane, concave toward the interior of the lens, and the edge portion is curved toward the object plane. The object-side surface 271 of the seventh lens and the image-side surface 272 of the seventh lens are both relatively flat, and the ratio of the sag to the aperture is less than 0.2, that is,

and

In the optical imaging system 2 of the seven-piece aspheric structure proposed in the first embodiment, the fifth lens 25 is designed in a recurve shape, which can share a part of the diopter of the sixth lens 26, so that the sixth lens 26 can be thinned. The optical imaging system 2 can control the ratio of the edge thickness to the center thickness of the fourth mirror 24, the fifth mirror 25 and the sixth mirror 26 to be within 0.2<DT/DC<4, and also control the thickness of the seventh mirror 27. Thickness ratio, and can improve the image surface bending problem caused by large sensor size, the optical imaging system 2 can solve the stray light problem well, greatly reduce the camera module face error, eccentricity, concentricity and inclination error Tolerance sensitivity, improve the camera module yield.

The optical path parameters of the lens in the optical imaging system 2 of the first embodiment, including the radius of curvature, thickness, refractive index nd, Abbe coefficient Vd, clear aperture, conic coefficient, and the focal length of each lens are shown in Table 1.

The first lens 21 has a positive refractive power. The first lens 21 is an optical material component with a low refractive index and a high dispersion coefficient, the refractive index nd<1.58, and the dispersion coefficient vd>50. The refractive index nd=1.544502, the Abbe coefficient vd=55.986991, and the focal length is 5.6502358mm.

The second lens 22 has a negative refractive power, the second lens 22 is an optical material component with high refractive index and low dispersion coefficient, the refractive index nd>1.60, and the dispersion coefficient vd<30, which is preferred in the first embodiment. The refractive index nd=1.661319, the Abbe coefficient vd=20.374576, and the focal length is -12.584821mm.

The third lens 23 has a positive refractive power, the third lens 23 is an optical material component with a low refractive index and a high dispersion coefficient, the refractive index nd<1.58, and the dispersion coefficient vd>50. The refractive index nd=1.544502, the Abbe coefficient vd=55.986991, and the focal length is 6.4870885mm.

The fourth lens 24 has a diopter, the fourth lens 24 is an optical material component with high refractive index and low dispersion coefficient, the refractive index nd>1.60, and the dispersion coefficient vd<30, in the first embodiment, the refractive index is preferably The rate nd=1.661319, the Abbe coefficient vd=20.374576, and the focal length is -5.3258553mm.

The fifth lens 25 has a diopter, and the fifth lens 25 is an optical material component with a low refractive index and a high dispersion coefficient, the refractive index nd<1.58, and the dispersion coefficient vd>50. The rate nd=1.544502, the Abbe coefficient vd=55.986991, and the focal length is 3.7967055mm.

The sixth lens 26 has a diopter, the sixth lens 26 is an optical material component with high refractive index and low dispersion coefficient, the refractive index nd>1.60, and the dispersion coefficient vd<30. In the first embodiment, the refractive index is preferably The rate nd=1.661319, the Abbe coefficient vd=20.374576, and the focal length is 5.3048433mm.

The seventh lens 27 has a diopter, and the seventh lens 27 is an optical material component with a low refractive index and a high dispersion coefficient, the refractive index nd<1.58, and the dispersion coefficient vd>50. The rate nd=1.544919, the Abbe coefficient vd=55.929938, and the focal length is -2.4182302mm.

Table 1 The optical path parameters of the lens in the optical imaging system 2 of the first embodiment:

Table 2 shows the aspheric coefficients of each mirror surface in the optical imaging system 2 of the first embodiment, from the quadratic term coefficient a1 to the sixteenth-order coefficient a8. The aspheric surface, its expression is as follows:

Among them, z is the sag height (SAG); c is the curvature, which is the reciprocal of the curvature radius; r is the radius of the aspheric aperture; a1, a2, a3... are the aspheric coefficients.

Table 2 Aspheric coefficients of each mirror surface in the optical imaging system 2 of the first embodiment:

The optical path diagram of the optical imaging system 2 in the first embodiment is shown in Figure 10, and its MTF curve is shown in Figure 11. At the position of 110 line pairs, the modulation transfer function of the central field of view exceeds 0.82, and the edge 1 field of view The worst modulation transfer function of , also exceeds 0.55, and the modulation transfer functions of other fields of view are all above 0.6. The MTF-depth of focus curve is shown in Figure 12. The MTF at the focal position is relatively concentrated, and there is almost no focus shift caused by field curvature. The point diagram is shown in Figure 13. The size of the dot pattern is about 1 micron, and the curve of field curvature and distortion is shown in Figure 14. The F-Tan(θ) is controlled within 1.5%, and the design result reaches the expected target. The fifth lens 25 and the sixth lens 26 are designed to be relatively flat, and the image side surface 262 of the sixth lens has no particularly protruding part, which greatly improves the tolerance sensitivity of the lens, and also solves the problem of stray light, improving the camera. yield rate.

Embodiment 2

Referring to FIGS. 15 to 22 , the second embodiment provides an optical imaging system. The optical imaging system 2 is a seven-piece aspherical structure, including a first lens 21 , a first lens 21 , a The second lens 22, the third lens 23, the fourth lens 24, the fifth lens 25, the sixth lens 26, the seventh lens 27, the infrared filter 28 and the image sensor 29, the aperture stop of which is located on the image side surface 212 of the first lens superior.

An optical imaging system 2 provided in the second embodiment, the cross-sectional view of which is shown in FIG. 15 , the combined focal length of the optical imaging system 2 is in the range of 3.65mm<f<7.5mm, and the diagonal size of the image plane is larger than 6.4mm. In the second embodiment, the combined focal length of the optical imaging system 2 is preferably: f=4.2878353mm.

所述第一镜片21 为低折射率、高色散系数的光学材料构件，其折射率nd＜1.58，其色散系数 vd＞50。The cross-sectional view of the first lens 21 is shown in FIG. 16, which has a positive refractive power, the first lens 21 has a first lens object side surface 211 and a first lens image side surface 212, the first lens object side surface 211 and the image-side surface 212 of the first lens are both curved toward the image plane, and the ratio of the focal length f1 of the first lens 21 to the combined focal length f of the optical imaging system 2 is

The first lens 21 is an optical material member with a low refractive index and a high dispersion coefficient, the refractive index nd<1.58, and the dispersion coefficient vd>50.

所述第二镜片22为高折射率、低色散系数的光学材料构件，其折射率nd＞1.6，其色散系数vd＜30。The cross-sectional view of the second lens 22 is shown in FIG. 17, which has negative power, the center thickness of the second lens 22 is thinner than the edge thickness, the second lens 22 has a second lens object side surface 221 and a second lens The image-side surface 222 of the lens, the object-side surface 221 of the second lens is curved toward the image plane, and the image-side surface 222 of the second lens is also curved toward the image plane. The focal length f2 of the second lens 22 is related to the optical imaging system The ratio of the combined focal length f of 2 is

The second lens 22 is an optical material component with a high refractive index and a low dispersion coefficient, the refractive index nd>1.6, and the dispersion coefficient vd<30.

所述第三镜片 23为低折射率、高色散系数的光学材料构件，其折射率nd＜1.58，其色散系数vd＞50。The cross-sectional view of the third lens 23 is shown in FIG. 18, which has positive refractive power, the third lens 23 has a third lens object side surface 231 and a third lens image side surface 232, the third lens object side surface 231 has a slightly recurved shape, the center part of which is curved toward the image plane, and the edge part is curved toward the object side. The image-side surface 232 of the third lens is curved toward the object plane. The focal length f3 of the third lens 23 is related to the optical imaging. The ratio of the combined focal length f of system 2 is

The third lens 23 is an optical material member with a low refractive index and a high dispersion coefficient, the refractive index nd<1.58, and the dispersion coefficient vd>50.

所述第四镜片24为高折射率、低色散系数的光学材料构件，其折射率nd＞1.6，其色散系数vd ＜30。The cross-sectional view of the fourth lens 24 is shown in FIG. 19, which has a diopter, the fourth lens 24 has a fourth lens object side surface 241 and a fourth lens image side surface 242, the fourth lens object side surface 241 and the image-side surface 242 of the fourth lens are both curved toward the object plane, and the ratio of the focal length f4 of the fourth lens 24 to the combined focal length f of the optical imaging system 2 is

The fourth lens 24 is an optical material component with a high refractive index and a low dispersion coefficient, the refractive index nd>1.6, and the dispersion coefficient vd <30.

所述第五镜片物侧表面251，其曲率半径R₂₅₁与光学成像系统2的组合焦距f的比值为

所述第五镜片25的焦距f5与光学成像系统2的组合焦距f 的比值为

The cross-sectional view of the fifth lens 25 is shown in FIG. 20, which has a diopter, the fifth lens 25 has a fifth lens object side surface 251 and a fifth lens image side surface 252, and the fifth lens object side surface 251 It is a recurve shape, the center part is convex toward the object surface, the area between the center part and the edge part is curved toward the image plane direction, and the edge parts of the object side surface 251 of the fifth lens and the image side surface 252 of the fifth lens, They are all curved in the direction of the object plane, and their shape is an Arabic numeral "3". Through the inverse curvature design of the fifth lens 25, it can share a part of the diopter of the sixth lens 26, so that the thickness of the sixth lens 26 can be adjusted. In the thinning design, the curved surface design of the object-side surface 251 of the fifth lens is relatively gentle, and the ratio of the sag to the optical clear aperture is less than 0.2, that is,

The ratio of the curvature radius R ₂₅₁ of the object-side surface 251 of the fifth lens to the combined focal length f of the optical imaging system 2 is

The ratio of the focal length f5 of the fifth lens 25 to the combined focal length f of the optical imaging system 2 is

A cross-sectional view of the sixth lens 26 is shown in FIG. 21, which has a diopter, the sixth lens 26 has a sixth lens object side surface 261 and a sixth lens image side surface 262, the sixth lens object side surface 261 It has a slightly recurve shape, its central part is curved toward the image plane, convex toward the object plane, and the edge portion is curved toward the object plane. The image side surface 262 of the sixth lens is curved toward the object plane, toward the image plane. The direction is convex, and the ratio of the focal length f6 of the sixth lens 26 to the combined focal length f of the optical imaging system 2 is

和

The cross-sectional view of the seventh lens 27 is shown in FIG. 22, which has diopter. The seventh lens 27 is thinner in the middle, gradually thickens from the middle to the edge, and then becomes thinner again. The ratio of the thickest part to the thinnest part is less than 3, the seventh lens 27 has a seventh lens object side surface 271 and a seventh lens image side surface 272, and the center part of the seventh lens object side surface 271 is in the direction of the object plane Curved, concave to the inside of the lens, and the edge portion is curved toward the image plane direction, the center portion of the image side surface 272 of the seventh lens is curved toward the image plane direction, concave toward the inside of the lens, and the edge portion is curved toward the object plane direction, The object-side surface 271 of the seventh lens and the image-side surface 272 of the seventh lens are both relatively flat, and the ratios of the sag to the aperture are both less than 0.2, that is,

and

In the optical imaging system 2 of the seven-piece aspheric structure proposed in the second embodiment, the fifth lens 25 is designed in a recurve shape, which can share a part of the diopter of the sixth lens 26, so that the sixth lens 26 can be thinned. The optical imaging system 2 can control the ratio of the edge thickness to the center thickness of the fourth mirror 24, the fifth mirror 25 and the sixth mirror 26 to be within 0.2<DT/DC<4, and also control the thickness of the seventh mirror 27. Thickness ratio, and can improve the image surface bending problem caused by large sensor size, the optical imaging system 2 can solve the stray light problem well, greatly reduce the camera module face error, eccentricity, concentricity and inclination error Tolerance sensitivity, improve the camera module yield.

The optical path parameters of the lens in the optical imaging system 2 of the second embodiment, including curvature radius, thickness, refractive index nd, Abbe coefficient Vd, clear aperture, conic coefficient, and the focal length of each lens are shown in Table 3.

The first lens 21 has a positive refractive power, and the first lens 21 is an optical material component with a low refractive index and a high dispersion coefficient, the refractive index nd<1.58, and the dispersion coefficient vd>50. The refractive index nd=1.544502, the Abbe coefficient vd=55.986991, and the focal length is 5.7430798mm.

The second lens 22 has a negative diopter, the second lens 22 is an optical material component with high refractive index and low dispersion coefficient, the refractive index nd>1.60, and the dispersion coefficient vd<30, which is preferred in the second embodiment The refractive index nd=1.661319, the Abbe coefficient vd=20.374576, and the focal length is -17.3394354mm.

The third lens 23 has a positive refractive power. The third lens 23 is an optical material component with a low refractive index and a high dispersion coefficient, the refractive index nd<1.58, and the dispersion coefficient vd>50. The refractive index nd=1.544502, the Abbe coefficient vd=55.986991, and the focal length is 9.1200987mm.

The fourth lens 24 has a diopter, and the fourth lens 24 is an optical material component with high refractive index and low dispersion coefficient, and its refractive index nd>1.60, its dispersion coefficient vd<30, and its refractive index is preferred in the second embodiment. The rate nd=1.635517, the Abbe coefficient vd=23.971841, and the focal length is -10.2106903mm.

The fifth lens 25 has a diopter, and the fifth lens 25 is an optical material component with high refractive index and low dispersion coefficient, the refractive index nd>1.60, and the dispersion coefficient vd<30. In the second embodiment, the refractive index is preferably The rate nd=1.671371, the Abbe coefficient vd=19.244900, and the focal length is -65.7029839mm.

The sixth lens 26 has a diopter, the sixth lens 26 is an optical material component with a low refractive index and a high dispersion coefficient, its refractive index nd<1.58, and its dispersion coefficient vd>50, and its refractive index is preferred in the second embodiment. The rate nd=1.544502, the Abbe coefficient vd=55.986991, and the focal length is 2.6088521mm.

The seventh lens 27 has a diopter, and the seventh lens 27 is an optical material component with a low refractive index and a high dispersion coefficient, the refractive index nd<1.58, and the dispersion coefficient vd>50. The rate nd=1.544502, the Abbe coefficient vd=55.986991, and the focal length is -2.2351735mm.

Table 3 The optical path parameters of the lens in the optical imaging system 2 of the second embodiment:

Table 4 shows the aspheric coefficients of each mirror surface in the optical imaging system 2 of the second embodiment, from the quadratic term coefficient a1 to the sixteenth-order coefficient a8. The aspheric surface, its expression is as follows:

Among them, z is the sag height (SAG); c is the curvature, which is the reciprocal of the curvature radius; r is the radius of the aspheric aperture; a1, a2, a3... are the aspheric coefficients.

Table 4 Aspheric coefficients of each mirror surface in the optical imaging system 2 of the second embodiment:

The optical path diagram of the optical imaging system 2 of the second embodiment is shown in Fig. 23, and the dot diagram is shown in Fig. 24. The minimum root mean square dot diagram of the central field of view is about 1 micron, and its field curvature and distortion As shown in Figure 25, its F-Tan(θ) is controlled within 1.5%, and the design result reaches the expected target. At the same time, since the fourth lens 24, the fifth lens 25 and the sixth lens 26 are all designed to be relatively flat, The image side surface 262 of the sixth lens does not have a particularly protruding part. The thickest part in the center is no more than twice the thickness of the thinnest part at the edge, which greatly improves the tolerance sensitivity of the lens and also solves the problem of stray light. Improve the camera yield.

Embodiment 3

Referring to FIGS. 26 to 32 , the third embodiment provides an optical imaging system. The optical imaging system 2 is a seven-piece aspherical structure, including a first lens 21 , a first lens 21 , a second lens arranged in sequence from the object side to the image side The second mirror 22, the third mirror 23, the fourth mirror 24, the fifth mirror 25, the sixth mirror 26, the seventh mirror 27, the infrared filter 28 and the image sensor 29, wherein the second mirror 22 and the third mirror 23 are glued together One piece, glued by Canadian glue, with the aperture stop located on the image side surface 212 of the first lens.

The cross-sectional view of an optical imaging system 2 provided in the third embodiment is shown in FIG. 26 , the combined focal length of the optical imaging system 2 is in the range of 3.65mm<f<7.5mm, and the diagonal size of the image plane is larger than 6.4mm, preferably the combined focal length of the optical imaging system 2 in the first embodiment is: f = 3.8186254mm.

所述第一镜片21 为低折射率、高色散系数的光学材料构件，其折射率nd＜1.58，其色散系数 vd＞50。The cross-sectional view of the first lens 21 is shown in FIG. 27 , which has a positive refractive power, the first lens 21 has a first lens object side surface 211 and a first lens image side surface 212 , the first lens object side surface 211 and the image-side surface 212 of the first lens are both curved toward the image plane, and the ratio of the focal length f1 of the first lens 21 to the combined focal length f of the optical imaging system 2 is

The first lens 21 is an optical material member with a low refractive index and a high dispersion coefficient, the refractive index nd<1.58, and the dispersion coefficient vd>50.

所述第二镜片22为高折射率、低色散系数的光学材料构件，其折射率nd＞1.6，其色散系数vd ＜30。The second lens 22 and the third lens 23 are cemented together to form a set of aspheric cemented lenses, the cross-sectional view of which is shown in FIG. 28 , the second lens 22 has a negative refractive power, and the center of the second lens 22 The thickness is thinner than the edge thickness, the second lens 22 has a second lens object side surface 221 and a second lens image side surface 222, the second lens object side surface 221 is slightly recurved, the second lens object side surface 222 The center part of the surface 221 is curved toward the image plane, and the edge part is slightly curved toward the object side; the image-side surface 222 of the second lens is curved toward the image plane, and the focal length f2 of the second lens 22 is related to the optical imaging system. The ratio of the combined focal length f of 2 is

The second lens 22 is an optical material component with a high refractive index and a low dispersion coefficient, the refractive index nd>1.6, and the dispersion coefficient vd <30.

所述第三镜片23为低折射率、高色散系数的光学材料构件，其折射率nd＜1.58，其色散系数vd＞50。The third lens 23 has a positive refractive power, the third lens 23 has a third lens object side surface 231 and a third lens image side surface 232, the third lens object side surface 231 and the second lens image side surface 222 Similarly, the object-side surface 231 of the third lens and the image-side surface 222 of the second lens have the same aspheric coefficient, the object-side surface 231 of the third lens is curved toward the image plane, and the object-side surface 231 of the third lens and the second lens are The image-side surfaces 222 are glued together by Canadian glue, the image-side surface 232 of the third lens is curved toward the object surface, and the ratio of the focal length f3 of the third lens 23 to the combined focal length f of the optical imaging system 2 is

The third lens 23 is an optical material component with a low refractive index and a high dispersion coefficient, the refractive index nd<1.58, and the dispersion coefficient vd>50.

所述第四镜片24为高折射率、低色散系数的光学材料构件，其折射率nd＞1.6，其色散系数vd ＜30。A cross-sectional view of the fourth lens 24 is shown in FIG. 29, which has a diopter, the fourth lens 24 has a fourth lens object side surface 241 and a fourth lens image side surface 242, the fourth lens object side surface 241 and the image-side surface 242 of the fourth lens are both curved toward the object plane, and the ratio of the focal length f4 of the fourth lens 24 to the combined focal length f of the optical imaging system 2 is

The fourth lens 24 is an optical material component with a high refractive index and a low dispersion coefficient, the refractive index nd>1.6, and the dispersion coefficient vd <30.

所述第五镜片物侧表面251，其曲率半径R₂₅₁与光学成像系统2的组合焦距f的比值为

所述第五镜片25的焦距f5与光学成像系统2的组合焦距f 的比值为

A cross-sectional view of the fifth lens 25 is shown in FIG. 30, which has a diopter, the fifth lens 25 has a fifth lens object side surface 251 and a fifth lens image side surface 252, the fifth lens object side surface 251 It is a recurve shape, the center part is convex toward the object surface, the area between the center part and the edge part is curved toward the image plane direction, and the edge parts of the object side surface 251 of the fifth lens and the image side surface 252 of the fifth lens, They are all curved in the direction of the object plane, and their shape is an Arabic numeral "3". Through the inverse curvature design of the fifth lens 25, it can share a part of the diopter of the sixth lens 26, so that the thickness of the sixth lens 26 can be adjusted. In the thinning design, the curved surface design of the object-side surface 251 of the fifth lens is relatively gentle, and the ratio of the sagittal height to the optical clear aperture is less than 0.2, that is,

The ratio of the curvature radius R ₂₅₁ of the object-side surface 251 of the fifth lens to the combined focal length f of the optical imaging system 2 is

The ratio of the focal length f5 of the fifth lens 25 to the combined focal length f of the optical imaging system 2 is

A cross-sectional view of the sixth lens 26 is shown in FIG. 31, which has a diopter, the sixth lens 26 has a sixth lens object side surface 261 and a sixth lens image side surface 262, the sixth lens object side surface 261 It has a slightly recurve shape, its central part is curved toward the image plane, convex toward the object plane, and the edge portion is curved toward the object plane. The image side surface 262 of the sixth lens is curved toward the object plane, toward the image plane. The direction is convex, and the ratio of the focal length f6 of the sixth lens 26 to the combined focal length f of the optical imaging system 2 is

和

The cross-sectional view of the seventh lens 27 is shown in FIG. 32, which has diopter. The seventh lens 27 is thinner in the middle, gradually thickens from the center to the edge, and then becomes thinner again. The ratio of the thickness to the thinnest part is less than 3, the seventh lens 27 has a seventh lens object side surface 271 and a seventh lens image side surface 272, and the center part of the seventh lens object side surface 271 is curved toward the object plane , concave to the inside of the lens, and the edge portion is curved toward the image plane. The center portion of the image side surface 272 of the seventh lens is curved toward the image plane, concave toward the interior of the lens, and the edge portion is curved toward the object plane. The object-side surface 271 of the seventh lens and the image-side surface 272 of the seventh lens are relatively gentle, and the ratio of the sag to the aperture is less than 0.2, that is,

and

In the optical imaging system 2 of the seven-piece aspheric structure proposed in the third embodiment, the fifth lens 25 is designed in a recurve shape, which can share a part of the diopter of the sixth lens 26, so that the sixth lens 26 can be thinned. The optical imaging system 2 can control the ratio of the edge thickness to the center thickness of the fourth mirror 24, the fifth mirror 25 and the sixth mirror 26 to be within 0.2<DT/DC<4, and also control the thickness of the seventh mirror 27. Thickness ratio, and can improve the image surface bending problem caused by large sensor size, the optical imaging system 2 can solve the stray light problem well, greatly reduce the camera module face error, eccentricity, concentricity and inclination error Tolerance sensitivity, improve the camera module yield.

The optical path parameters of the lens in the optical imaging system 2 of the third embodiment, including the radius of curvature, thickness, refractive index nd, Abbe coefficient Vd, clear aperture, conic coefficient, and the focal length of each lens are shown in Table 5.

The first lens 21 has a positive refractive power, and the first lens 21 is an optical material component with a low refractive index and a high dispersion coefficient, the refractive index nd<1.58, and the dispersion coefficient vd>50. The refractive index nd=1.544502, the Abbe coefficient vd=55.986991, and the focal length is 5.3818184mm.

The second lens 22 has a negative refractive power. The second lens 22 is an optical material component with a high refractive index and a low dispersion coefficient. The refractive index nd=1.661319, the Abbe coefficient vd=20.374576, and the focal length is -10.7468271mm.

The third lens 23 has a positive refractive power, and the third lens 23 is an optical material component with a low refractive index and a high dispersion coefficient, the refractive index nd<1.58, and the dispersion coefficient vd>50. The refractive index nd=1.544502, the Abbe coefficient vd=55.986991, and the focal length is 6.4297160mm.

The fourth lens 24 has a diopter, and the fourth lens 24 is an optical material component with a high refractive index and a low dispersion coefficient, the refractive index nd>1.60, and the dispersion coefficient vd<30. The rate nd=1.661319, the Abbe coefficient vd=20.374576, and the focal length is -4.7478218mm.

The fifth lens 25 has a diopter, and the fifth lens 25 is an optical material component with a low refractive index and a high dispersion coefficient, the refractive index nd<1.58, and the dispersion coefficient vd>50. In the third embodiment, the refractive index is preferably The rate nd=1.544502, the Abbe coefficient vd=55.986991, and the focal length is 2.9569209mm.

The sixth lens 26 has a diopter, the sixth lens 26 is an optical material component with a high refractive index and a low dispersion coefficient, the refractive index nd>1.60, and the dispersion coefficient vd<30. In the third embodiment, the refractive index is preferably The rate nd=1.661319, the Abbe coefficient vd=20.374576, and the focal length is 6.4275854mm.

The seventh lens 27 has a diopter, and the seventh lens 27 is an optical material component with a low refractive index and a high dispersion coefficient, the refractive index nd<1.58, and the dispersion coefficient vd>50. The rate nd=1.544502, the Abbe coefficient vd=55.986991, and the focal length is -2.3091884mm.

Table 5 The optical path parameters of the lens in the third optical imaging system 2 of this embodiment:

Table 6 shows the aspheric coefficients of each mirror surface in the optical imaging system 2 of the third embodiment, from the quadratic term coefficient a1 to the sixteenth-order coefficient a8. The aspheric surface, its expression is as follows:

Among them, z is the sag height (SAG); c is the curvature, which is the reciprocal of the curvature radius; r is the radius of the aspheric aperture; a1, a2, a3... are the aspheric coefficients.

Table 6 Aspheric coefficients of each mirror surface in the third optical imaging system 2 of the present embodiment:

The optical path diagram of the optical imaging system 2 in the third embodiment is shown in Figure 33, and its dot diagram is shown in Figure 34. The minimum root mean square dot diagram of the central field of view is about 1.5 microns, and its field curvature and distortion As shown in Figure 35, its F-Tan(θ) is controlled within 1.5%, and the design result reaches the expected target. At the same time, because the fourth lens 24, the fifth lens 25 and the sixth lens 26 are all designed to be relatively flat, The image side surface 262 of the sixth lens does not have a particularly protruding part, and the thickest part in the center is no more than 2 times thicker than the thinnest part at the edge, which greatly improves the tolerance sensitivity of the lens, and at the same time solves the problem of stray light electrically. Improve the camera yield.

Claims (10)

1. An optical imaging system, characterized in that the optical imaging system (2) is a seven-piece aspheric structure, comprising a first lens (21), a second lens (22), a third lens (23), a fourth lens (24), a fifth lens (25), a sixth lens (26), a seventh lens (27), an infrared filter (28) and an image sensor (29) arranged in order from an object side to an image side, the first lens (21) having a positive refractive power, the second lens (22) having a negative refractive power, the third lens (23) having a positive refractive power, the fourth lens (24) having a refractive power, the fifth lens (25) having a fifth lens object side surface (251) and a fifth image side surface (252), the fifth lens object side surface (251) being a sigmoidal shape, the central part is convex towards the object plane, the area between the central part and the edge part is curved towards the image plane, the edge part of the fifth lens (25) is curved towards the object plane, in the shape of the Arabic numerals "3", said sixth lens (26) having a refractive power, the sixth lens (26) having a sixth lens object side surface (261) and a sixth lens image side surface (262), a central part of the sixth lens object side surface (261) is convex towards the object plane direction, a central part of the sixth lens image side surface (262) is convex towards the image plane direction, the seventh lens (27), having a refractive power, the seventh lens (27) having a seventh lens object side surface (271) and a seventh lens image side surface (272), the center of the seventh lens object side surface (271) is concave towards the inside of the lens, and the center of the seventh lens image side surface (272) is concave towards the inside of the lens.

2. An optical imaging system according to claim 1, characterized in that the fourth (24), fifth (25) and sixth (26) lenses have a ratio of edge thickness to central thickness of: DT/DC is more than 0.2 and less than 4.

3. An optical imaging system according to claim 1, characterized in that the combined focal length of the optical imaging system (2) ranges from: f is more than 3.65mm and less than 7.5mm, and the diagonal size of the image surface is more than 6.4 mm.

4. The method of claim 1An optical imaging system, characterized in that the first lens (21) has a first lens object side surface (211) and a first lens image side surface (212), the first lens object side surface (211) and the first lens image side surface (212) are both curved towards the image plane direction, the ratio of the focal length f1 of the first lens (21) to the combined focal length f of the optical imaging system (2) is

The first lens (21) is an optical material component with low refractive index and high dispersion coefficient, the refractive index nd is less than 1.58, and the dispersion coefficient vd is more than 50.

5. An optical imaging system according to claim 1, characterized in that the second lens (22) has a central thickness thinner than the peripheral thickness, the ratio of the focal length f2 of the second lens (22) to the combined focal length f of the optical imaging system (2) being such that

The second lens (22) is an optical material component with high refractive index and low dispersion coefficient, the refractive index nd is more than 1.6, and the dispersion coefficient vd is less than 30.

6. An optical imaging system according to claim 1, characterized in that the ratio of the focal length f3 of the third lens element (23) to the combined focal length f of the optical imaging system (2) is

The third lens (23) is an optical material component with low refractive index and high dispersion coefficient, the refractive index nd of the third lens is less than 1.58, and the dispersion coefficient vd of the third lens is more than 50.

7. The optical imaging system of claim 1, wherein the fourth lens element (24) has a fourth lens element object-side surface (241) and a fourth lens element image-side surface (242), the fourth lens element object-side surface (241) is curved toward the object plane, and a focal length f4 of the fourth lens element (24) and the optical imaging system(2) Has a ratio of the combined focal lengths f of

The fourth lens (24) is an optical material component with high refractive index and low dispersion coefficient, the refractive index nd is more than 1.6, and the dispersion coefficient vd is less than 30.

8. An optical imaging system according to claim 1, characterized in that the fifth lens (25) has a fifth lens object-side surface (251) and a fifth lens image-side surface (252), the curved design of the fifth lens object-side surface (251) being relatively gentle with a vector height to optical clear aperture ratio of less than 0.2, i.e. the ratio of the optical clear aperture is smaller than

Its radius of curvature R₂₅₁The ratio of the combined focal length f of the optical imaging system (2) to the combined focal length f is

The ratio of the focal length f5 of the fifth lens (25) to the combined focal length f of the optical imaging system (2) is

9. An optical imaging system according to claim 1, characterized in that the ratio of the focal length f6 of the sixth lens element (26) to the combined focal length f of the optical imaging system (2) is

10. An optical imaging system according to claim 1, characterized in that the seventh lens (27) is thinner in the middle, gradually thicker from the middle to the edge and then thinner, the ratio of the thickest to the thinnest part of the seventh lens (27) is less than 3, the object-side surface (271) and the image-side surface (27) of the seventh lens are2) Are all relatively gentle, and the ratio of rise to caliber is less than 0.2, namely

And

Images