WO2022204986A1 - Optical imaging system, image capture module and electronic device - Google Patents

Abstract

The present application relates to the technical field of optical imaging, and in particular to an optical imaging system, an image capture module and an electronic device. The optical imaging system sequentially comprises, from an object side to an image side, a first lens having positive focal power; a second lens having negative focal power; a third lens having positive focal power; a fourth lens having focal power; a fifth lens having focal power, with an object-side surface of the fifth lens being concave near an optical axis, and an image-side surface of the fifth lens being convex near the optical axis; a sixth lens having focal power; a seventh lens having negative focal power, with an image-side surface of the seventh lens being concave near the optical axis; an eighth lens having focal power, with an object-side surface of the eighth lens being convex near the optical axis; and a ninth lens having focal power, with an object-side surface of the ninth lens being convex near the optical axis, and an image-side surface of the ninth lens being concave near the optical axis. According to the optical imaging system in the present application, the imaging effect of the optical imaging system can be improved.

Description

Optical imaging systems, imaging modules and electronic equipment technical field

The present application relates to the technical field of optical imaging, and in particular, to an optical imaging system, an imaging module and an electronic device.

Background technique

With the expansion of Internet coverage and the development of Internet technology, the replacement cycle of mobile phones, the main terminal that carries Internet applications, is getting shorter and shorter, and the shooting functions of mobile phones are becoming more and more powerful. In addition to the continuous improvement of pixels, it can adapt to different There are more and more types of lenses in the shooting environment, and at the same time, the requirements for a single type of lens are becoming more and more strict, showing a trend of mobile phone lenses developing into professional camera lenses. Among them, the telephoto lens can obtain a shallower depth of field because of its long focal length, so it can better deal with the details of the distant scene and achieve the imaging effect of compressed distance.

However, the imaging effect of the existing telephoto lens mobile phone is poor, resulting in poor photographing effect and affecting the user's experience.

SUMMARY OF THE INVENTION

The present application provides an optical imaging system, and the imaging effect of the optical imaging system is good.

In order to achieve the above purpose, the present application provides an optical imaging system, which sequentially includes:

The first lens with positive refractive power, the object side of the first lens is convex at the near optical axis, and the image side of the first lens is concave at the near optical axis;

The second lens with negative refractive power, the object side of the second lens is convex at the near optical axis, and the image side of the second lens is concave at the near optical axis;

a third lens with positive refractive power, the object side of the third lens is convex at the near optical axis;

a fourth lens with optical power, wherein the image side surface of the fourth lens is concave at the near optical axis;

The fifth lens with optical power, the object side of the fifth lens is concave at the near optical axis, and the image side of the fifth lens is convex at the near optical axis;

The sixth lens with optical power, the object side of the sixth lens is concave at the near optical axis, and the image side of the sixth lens is convex at the near optical axis;

a seventh lens with negative refractive power, the image side of the seventh lens is concave at the near optical axis;

an eighth lens with optical power, the object side of the eighth lens is convex at the near optical axis;

A ninth lens with optical power, the object side of the ninth lens is convex at the near optical axis, and the image side of the ninth lens is concave at the near optical axis.

Wherein, both the object side surface of the ninth lens and the image side surface of the ninth lens are aspheric surfaces, and at least one of the object side surface and the image side surface of the ninth lens is provided with at least one inflection point.

In the optical imaging system in the present application, the first lens has positive refractive power, and the object side of the first lens is convex at the near optical axis, and the image side is concave at the near optical axis, which is beneficial to improve the corrected image of the first lens. The poor effect can also ensure that the first lens has a suitable medium thickness, and can achieve a reasonable matching effect with the rear lens during assembly; the second lens has a negative refractive power, and the object side of the second lens at the near optical axis is Convex, the image side is concave at the near optical axis, so that the second lens has a strong negative bending force, which is conducive to the miniaturization of the optical imaging system; the fifth lens has optical power, and the object side of the fifth lens is The near-optical axis is concave, and the image side is convex at the near-optical axis; it is beneficial to the reasonable deflection of the light on the object side of the fifth lens, especially the reasonable light angle of the outer field of view can ensure that the outer field of view can obtain a higher Relative illuminance, and ensure good imaging quality; the seventh lens has negative refractive power, and the image side of the seventh lens is concave at the near optical axis; it is beneficial to shorten the total length of the optical imaging system, and correct the aberration generated by the front lens. Helps maintain the aberration balance of the optical imaging system; the eighth lens has optical power, and the object side of the eighth lens is convex at the near optical axis; wherein, an inflection point is set on the object side of the eighth lens, and the inflection point is set on the object side of the eighth lens. The inflection point cooperates with the inflection point of the seventh lens to the side, which is conducive to correcting aberrations and improving imaging quality; the ninth lens has optical power, and the object side of the ninth lens is convex at the near optical axis, and the image side is at The near optical axis is concave; the setting method of the ninth lens is conducive to the better convergence of the light from the central field of view to the center of the image plane, which acts as a base pad for the imaging of the entire image plane, and has aberration correction effect, which is guaranteed together with the front lens. High image quality. Therefore, the imaging effect of the optical imaging system can be improved by setting the optical power of the first lens to the ninth lens and setting the image side surface and the object side surface of the first lens to the ninth lens.

Preferably, the optical imaging system satisfies the following conditional formula:

6<f2/(r22-r21)<14.5;

Wherein, f2 is the effective focal length of the second lens; r22 is the radius of curvature of the image side of the second lens at the optical axis; r21 is the radius of curvature of the object side of the second lens at the optical axis.

By satisfying the limitation of the conditional expression, reasonably configuring the relationship between the effective focal length of the second lens and the radius of curvature of the object image side of the second lens can make the second lens generate enough negative refractive power to balance the generation of the first lens, the third lens and the fourth lens The aberration in the positive direction can be effectively controlled; in addition, the shape of the image side surface of the second lens can be effectively controlled to have a suitable curvature, and the sensitivity and processing difficulty of the second lens can be reduced. When f2/(r22-r21)≥14.5, the negative refractive power provided by the second lens is not enough to balance the positive refractive power of the front lens group, which is not conducive to the overall aberration correction; when f2/(r22-r21)≤6, The difference between the curvature radius of the second lens on the object side and the image side is too large. On the one hand, the difference in the degree of curvature of the second lens surface is too large, which is not enough to obtain a suitable deflection angle for the light, which is not conducive to shortening the total optical length and limits the image height. , affecting the imaging quality; on the other hand, the surface shape of the second lens is too curved, which will increase the difficulty of lens molding and assembly.

Preferably, the optical imaging system satisfies the following conditional formula:

15<f7/sag72<120;

Wherein, f7 is the effective focal length of the seventh lens; sag72 is the sagittal height of the image side surface of the seventh lens at the maximum effective diameter.

By satisfying the limitation of the conditional expression, controlling the ratio of the effective focal length of the seventh lens to the sagittal height of the image side of the seventh lens is within a reasonable range, which is beneficial to control the surface shape of the seventh lens, and complements the shape and aberration correction of the front and rear lenses. It also helps that the light can smoothly transition in the rear lens group to reach the image plane at a reasonable angle of incidence, ensuring that the on-axis field of view can obtain high imaging quality.

Preferably, the optical imaging system satisfies the following conditional formula:

15<r81/|sag81|<135;

Wherein, r81 is the radius of curvature of the object side of the eighth lens at the optical axis; sag81 is the sag of the object side of the eighth lens at the maximum effective diameter.

By satisfying the limitation of the conditional expression, configuring the ratio of the curvature radius of the object side of the eighth lens to the sagittal height of the object side of the eighth lens is within a reasonable range, which is helpful to constrain the shape trend and surface inclination of the eighth lens, and provides the optical The imaging system contributes with an appropriate focal length to achieve telephoto characteristics. When r81/|sag81|≥135, the surface of the eighth lens is not curved enough and tends to be flat, and the refractive power provided is not enough to support the telephoto characteristics of the overall system; when r81/|sag81| is less than or equal to 15, the surface of the eighth lens is If the shape is too curved, it is easy to cause the deflection angle of the light in the edge field of view to be too large, and the angle of the light incident on the image plane of the eighth lens will be too large, which will eventually lead to the degradation of the edge imaging quality.

Preferably, the optical imaging system satisfies the following conditional formula:

EFL/TTL>1;

Wherein, EFL is the effective focal length of the optical imaging system, and TTL is the distance on the optical axis from the object side of the first lens to the imaging surface of the optical system.

By satisfying the limitation of the conditional expression, it is beneficial to obtain the telephoto characteristic of the optical imaging system, and at the same time, the optical imaging system can have a relatively compact structure by reducing the total length of the optical imaging system, thereby realizing the miniaturization and portability of the lens.

Preferably, the optical imaging system satisfies the following conditional formula:

f1/sd11<4.2;

Wherein, f1 is the effective focal length of the first lens; sd11 is the maximum effective semi-aperture of the object side of the first lens.

By satisfying the limitation of the conditional expression, controlling the ratio of the effective focal length of the first lens to the maximum effective semi-aperture of the object side of the first lens is beneficial to increase the field of view on the premise of maintaining telephoto. The control of the type can compress the incident angle of light, reduce pupil aberration, and then help to improve the imaging quality. When f1/sd11 ≥ 4.2, the positive refractive power provided by the first lens is too small, which is not conducive to compressing the incident angle of light, and it is not easy for the rear lens to achieve spherical aberration correction balance, which eventually leads to a decrease in image quality.

Preferably, the optical imaging system satisfies the following conditional formula:

0.32<BFL/sd92<0.4;

Wherein, the minimum distance from the image side of the ninth lens of the BFL to the imaging plane of the optical imaging system in the direction of the optical axis, that is, the back focus; sd92 is the maximum effective semi-diameter of the image side of the ninth lens.

By satisfying the limitation of the conditional expression, rationally configuring the ratio of the back focus to the maximum effective half-aperture of the image side of the ninth lens can ensure the projection height of the light on the ninth lens, thereby obtaining sufficient light flux, so that the external field of view has a relatively high relative Illumination.

Preferably, the optical imaging system satisfies the following conditional formula:

IMGH*2/TTL>0.93;

Wherein, TTL is the distance from the object side of the first lens to the imaging plane of the optical system on the optical axis; ImgH is the half of the image height corresponding to the maximum angle of view of the optical system.

By satisfying the limitations of the conditional expression, it is possible to have a large image area while maintaining miniaturization, and to achieve telephoto shooting. In addition, the large image surface is also conducive to better presenting the details of the photographed object, thereby improving the imaging quality.

Preferably, the optical imaging system satisfies the following conditional formula:

tan(FOV/2)/ct19>0.12mm ^-1 ;

Wherein, FOV is the maximum angle of view of the optical imaging system; ct19 is the sum of the thicknesses of the first lens to the ninth lens on the optical axis.

By satisfying the limitation of the conditional expression, and by controlling the ratio of the maximum field of view to the sum of the thicknesses of the nine lenses on the optical axis to be greater than 0.12, it is beneficial to shorten the total length of the system and achieve ultra-thin characteristics. When tan(FOV/2)/ct19≤0.12, it is not conducive to the miniaturization of the optical imaging system, and the reduced field of view will also reduce the user experience.

Preferably, the optical imaging system satisfies the following conditional formula:

1.3<aet14/at14<1.75;

Among them, aet14 is the sum of the air gaps of the first lens to the fourth lens with the largest effective semi-aperture in the direction of the optical axis; at14 is the sum of the air gaps of the first lens to the fourth lens on the optical axis .

By satisfying the limitation of the conditional expression and reasonably controlling the above ratio, it is beneficial to shorten the total length of the system, and make each lens in the front lens group have a reasonable air gap at the optical axis and the maximum effective semi-aperture. In this way, the distance between the lenses is not It will be too small to increase the difficulty of lens assembly; the distance will not be too large so that the light cannot be reasonably transitioned, and the total optical length cannot be further compressed. When aet14/at14≥1.75, the air gap between the adjacent lenses of the front lens group at the maximum effective semi-aperture is too large, which will lead to a larger difference in the thickness of the lens and the thickness of the lens, uneven distribution of lens thickness, and reduced lens stability. During the assembly process of the lens, the thin part is easy to be broken, which increases the production cost; when aet14/at14≤1.3, the lens arrangement is too tight, and the assembly process is easy to squeeze, which increases the difficulty of assembly.

The present application also provides an imaging module, including any one of the optical systems, and having good imaging quality.

The present application also provides an electronic device, comprising a casing and the above-mentioned imaging module, wherein the imaging module is arranged in the casing, and by using the above-mentioned imaging module, the electronic device can have good imaging performance.

Description of drawings

1 is a schematic structural diagram of an optical imaging system according to a first embodiment of the present invention;

2 is a schematic diagram of longitudinal spherical aberration diagram, astigmatism curve diagram and distortion of the optical imaging system according to the first embodiment of the present invention;

3 is a schematic structural diagram of an optical imaging system according to a second embodiment of the present invention;

4 is a schematic diagram of a longitudinal spherical aberration diagram, an astigmatism curve diagram and distortion of the optical imaging system according to the second embodiment of the present invention;

5 is a schematic structural diagram of an optical imaging system according to a third embodiment of the present invention;

6 is a schematic diagram of longitudinal spherical aberration diagram, astigmatism curve diagram and distortion of the optical imaging system according to the third embodiment of the present invention;

7 is a schematic structural diagram of an optical imaging system according to a fourth embodiment of the present invention;

8 is a schematic diagram of longitudinal spherical aberration diagram, astigmatism curve diagram and distortion of the optical imaging system according to the fourth embodiment of the present invention;

9 is a schematic structural diagram of an optical imaging system according to a fifth embodiment of the present invention;

10 is a schematic diagram of longitudinal spherical aberration diagram, astigmatism curve diagram and distortion of the optical imaging system according to the fifth embodiment of the present invention;

11 is a schematic structural diagram of an optical imaging system according to a sixth embodiment of the present invention;

12 is a schematic diagram of longitudinal spherical aberration diagram, astigmatism curve diagram and distortion of the optical imaging system according to the sixth embodiment of the present invention.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings.

The terms used in the following embodiments are for the purpose of describing particular embodiments only, and are not intended to be limitations of the present application. As used in the specification of this application and the appended claims, the singular expressions "a," "an," "the," "above," "the," and "the" are intended to also Expressions such as "one or more" are included unless the context clearly dictates otherwise.

References in this specification to "one embodiment" or "some embodiments" and the like mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in one or more embodiments of the present application. Thus, appearances of the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in other embodiments," etc. in various places in this specification are not necessarily All refer to the same embodiment, but mean "one or more but not all embodiments" unless specifically emphasized otherwise. The terms "including", "including", "having" and their variants mean "including but not limited to" unless specifically emphasized otherwise.

Please refer to FIG. 1, an embodiment is provided. The present application provides an optical imaging system, which sequentially includes from the object side to the image side:

The first lens 1 with positive refractive power, the object side S2 of the first lens 1 is a convex surface at the near optical axis, and the image side S3 of the first lens 1 is a concave surface at the near optical axis;

The second lens 2 with negative refractive power, the object side S4 of the second lens 2 is a convex surface at the near optical axis, and the image side surface of the second lens 2 is a concave surface S5 at the near optical axis;

The third lens 3 with positive refractive power, the object side S6 of the third lens 3 is convex at the near optical axis;

The fourth lens 4 with optical power, the image side S9 of the fourth lens 4 is a concave surface at the near optical axis;

The fifth lens 5 with optical power, the object side S11 of the fifth lens 5 is a concave surface at the near optical axis, and the image side S12 of the fifth lens 5 is a convex surface at the near optical axis;

The sixth lens 6 with optical power, the object side S13 of the sixth lens 6 is a concave surface at the near optical axis, and the image side S14 of the sixth lens 6 is a convex surface at the near optical axis;

The seventh lens 7 with negative refractive power, the image side S16 of the seventh lens 7 is concave at the near optical axis;

The eighth lens 8 with optical power, the object side S17 of the eighth lens 8 is convex at the near optical axis;

For the ninth lens 9 with optical power, the object side S19 of the ninth lens 9 is convex at the near optical axis, and the image side S20 of the ninth lens 9 is concave at the near optical axis.

In the optical imaging system in this application, the first lens 1 has a positive refractive power, and the object side S2 of the first lens 1 is convex at the near optical axis, and the image side S3 is concave at the near optical axis, which is conducive to improving the first The aberration correction effect of the first lens 1 can also ensure that the first lens 1 has a suitable medium thickness, and can achieve the effect of reasonable cooperation with the rear lens during assembly; the second lens 2 has a negative refractive power, and the second lens 2 has a The object side S4 is convex at the near optical axis, and the image side S5 is concave at the near optical axis, so that the second lens 2 has a strong negative bending force, which is conducive to realizing the miniaturization of the optical imaging system; the fifth lens 5 With optical power, the object side S11 of the fifth lens 5 is concave at the near optical axis, and the image side S12 is convex at the near optical axis; it is beneficial to the reasonable deflection of the light on the object side of the fifth lens 5, especially the external The reasonable light angle of the field of view can ensure that the external field of view can obtain higher relative illuminance and ensure good imaging quality; the seventh lens 7 has a negative refractive power, and the image side S15 of the seventh lens 7 is at the near optical axis. Concave surface; it is beneficial to shorten the total length of the optical imaging system, correct the aberration generated by the front lens, and help to maintain the aberration balance of the optical imaging system; the eighth lens 8 has optical power, and the object side S17 of the eighth lens 8 is close to The optical axis is a convex surface; wherein, an inflection point is set on the object side of the eighth lens 8, which cooperates with the inflection point of the image side S16 of the seventh lens 7, which is conducive to correcting aberrations and improving imaging quality; The ninth lens 9 has optical power, and the object side S19 of the ninth lens 9 is convex at the near optical axis, and the image side S20 is concave at the near optical axis; the arrangement of the ninth lens 9 is conducive to the light of the central field of view. The good ones converge to the center of the image plane, acting as a base pad for the entire image plane imaging, and at the same time, it has the effect of aberration correction, and together with the front lens ensures high imaging quality. Therefore, the imaging effect of the optical imaging system can be improved by setting the optical power of the first lens 1 to the ninth lens 9 and the setting methods of the image side surface and the object side surface of the first lens 1 to the ninth lens 9 .

In some embodiments, both the object side S19 of the ninth lens 9 and the image side S20 of the ninth lens 9 are aspherical, and at least one of the object side S19 and the image side S20 of the ninth lens 9 is provided with at least one inflection point, and a first aperture S1 is also set at the first lens 1, a second aperture S10 is set between the fourth lens 4 and the fifth lens 5, and a ninth lens 9 is set between the image plane S23 With IR cut filter.

The first diaphragm S1 and the second diaphragm S10 are aperture diaphragms, which are used to control the amount of light entering the optical system 10, and at the same time can play the role of blocking ineffective light.

The shape of an aspheric surface is determined by the following formula:

where Z is the longitudinal distance between any point on the aspheric surface and the vertex of the surface, r is the distance from any point on the aspheric surface to the optical axis, c is the vertex curvature (the reciprocal of the radius of curvature), k is the conic constant, and Ai is the i-th order of the aspheric surface Correction factor.

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

Preferably, the optical imaging system satisfies the following conditional formula:

6<f2/(r22-r21)<14.5;

Wherein, f2 is the effective focal length of the second lens 2 ; r22 is the radius of curvature of the image side of the second lens 2 ; r21 is the radius of curvature of the object side of the second lens 2 . That is, f2/(r22-r21) can be any value within the range of (6, 14.5), for example, the value can be 6.458, 7.014, 9.107, 10.976, 11.572, 14.057, and so on.

Satisfying the above conditional formula, reasonably configure the relationship between the effective focal length of the second lens 2 and the curvature radius of the object image side of the second lens 2, so that the second lens 2 can generate enough negative refractive power to balance the first lens 1, the third lens 3 and the The aberration in the positive direction produced by the fourth lens 4; in addition, the shape of the image side of the second lens 2 on the object side can be effectively controlled to have a suitable curvature, thereby reducing the sensitivity and processing difficulty of the second lens 2. When f2/(r22-r21)≥14.5, the negative refractive power provided by the second lens 2 is not enough to balance the positive refractive power of the front lens group, which is not conducive to the overall aberration correction; when f2/(r22-r21)≤6 , the difference of the curvature radius of the second lens 2 on the object side and the image side is too large. On the one hand, the difference in the degree of curvature of the second lens 2 will be too large, which is not enough to obtain a suitable deflection angle for the light, which is not conducive to shortening the total optical length. In addition, the image height is limited, which affects the imaging quality; on the other hand, the 2-surface shape of the second lens is too curved, which will increase the difficulty of lens molding and assembly.

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

15<f7/sag72<120;

Wherein, f7 is the effective focal length of the seventh lens 7; sag72 is the sagittal height of the image side surface of the seventh lens at the maximum effective diameter. That is, f7/sag72 can be any value in the range of (15, 120), for example, the value can be 19.210, 25.234, 26.304, 50.383, 54.359, 116.770, etc.

The sagittal height is the distance from the center of the image side of the seventh lens 7 (ie the intersection of the object side and the optical axis) to the maximum effective aperture of the surface (ie the maximum effective diameter of the surface) in the direction parallel to the optical axis. When the sag value is positive, in the direction parallel to the optical axis of the system, the maximum effective clear aperture of the surface is closer to the image side of the system than the center of the surface; when the value is negative , in the direction parallel to the optical axis of the system, the maximum effective clear aperture of the surface is closer to the object side of the system than the center of the surface.

By satisfying the limitation of the conditional expression, controlling the ratio of the effective focal length of the seventh lens 7 to the sagittal height of the image side of the seventh lens 7 is within a reasonable range, which is beneficial to control the surface shape of the seventh lens 7, and the shape and aberration correction of the front and rear lenses. The combination of complementarity also helps the light to smoothly transition in the rear lens group to reach the image plane at a reasonable angle of incidence, ensuring that the on-axis field of view can obtain high imaging quality.

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

15<r81/|sag81|<135;

Wherein, r81 is the radius of curvature of the object side of the eighth lens 8 at the optical axis; sag81 is the sag of the object side of the eighth lens 8 at the maximum effective diameter. r81/|sag81| can be any value in the range of (15, 135), for example, the value can be 21.97, 47.62, 60.51, 123.71, 122.90, 131.17, etc.

By satisfying the limitation of the conditional expression, configuring the ratio of the curvature radius of the object side of the eighth lens 8 to the sag of the object side of the eighth lens 8 is within a reasonable range, which helps to constrain the shape trend and the surface inclination of the eighth lens 8, and provides The optical imaging system contributes with an appropriate focal length, thereby achieving telephoto characteristics. When r81/|sag81|≥135, the eighth lens 8 is not curved enough and tends to be flat, and the refractive power provided is not enough to support the telephoto characteristics of the overall system; when r81/|sag81| is less than or equal to 15, the eighth lens 8 If the surface is too curved, the deflection angle of the light in the edge field of view is easy to be too large, and the angle of the light incident on the image plane of the eighth lens 8 will be too large, which will eventually lead to the degradation of the edge imaging quality.

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

EFL/TTL>1;

Among them, EFL is the effective focal length of the optical imaging system, and TTL is the distance from the object side of the first lens to the imaging surface of the optical system on the optical axis, that is, the first surface of the first lens 1 (closer to the object) The distance from the intersection of the optical axis to the center of the image plane. EFL/TTL may be a value greater than 1, for example, the value may be 1.01, 1.02, 1.05, and so on.

By satisfying the limitation of the conditional expression, it is beneficial to obtain the telephoto characteristic of the optical imaging system, and at the same time, the optical imaging system can have a relatively compact structure by reducing the total length of the optical imaging system, thereby realizing the miniaturization and portability of the lens.

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

f1/sd11<4.2;

Wherein, f1 is the effective focal length of the first lens 1 ; sd11 is the maximum effective semi-diameter of the object side of the first lens 1 . That is, f1/sd11 can be any value less than 4.2, for example, the value can be 4.11, 4.10, 3.96, 3.94, 3.81 and so on.

By satisfying the limitation of the conditional expression, controlling the ratio of the effective focal length of the first lens 1 to the maximum effective semi-aperture of the object side of the first lens 1 is beneficial to increase the field of view on the premise of maintaining telephoto. In addition, for the first lens 1 The control of aperture and surface shape can compress the incident angle of light, reduce pupil aberration, and help improve imaging quality. When f1/sd11≥4.2, the positive refractive power provided by the first lens 1 is too small, which is not conducive to compressing the incident angle of light, and it is not easy for the rear lens to achieve spherical aberration correction balance, which ultimately leads to a decrease in image quality.

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

0.32<BFL/sd92<0.4;

Wherein, the minimum distance from the image side of the ninth lens of the BFL to the imaging plane of the optical imaging system in the direction of the optical axis, that is, the back focus; That is, BFL/sd92 can be any value within the range of (0.32, 0.4), for example, the value can be 0.34, 0.36, 0.37, 0.38, and so on.

By satisfying the limitation of the conditional expression, rationally configuring the ratio of the back focus to the maximum effective half-aperture of the image side of the ninth lens 9 can ensure the projection height of the light on the ninth lens 9, thereby obtaining sufficient light flux, so that the external field of view has a higher of relative illumination.

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

IMGH*2/TTL>0.93;

Wherein, TTL is the distance from the object side of the first lens to the imaging plane of the optical system on the optical axis; ImgH is the half of the image height corresponding to the maximum angle of view of the optical system. That is, IMGH*2/TTL can be any value greater than 0.93, for example, the value can be 0.937, 0.938, 0.964, and so on.

By satisfying the limitations of the conditional expression, it is possible to have a large image area while maintaining miniaturization, and to achieve telephoto shooting. In addition, the large image surface is also conducive to better presenting the details of the photographed object, thereby improving the imaging quality.

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

tan(FOV/2)/ct19>0.12mm ^-1 ;

Wherein, FOV is the maximum angle of view of the optical imaging system; ct19 is the sum of the thicknesses of the first lens to the ninth lens on the optical axis. That is, tan(FOV/2)/ct19 may be any value greater than 0.12, for example, the value may be 0.12, 0.13, 0.14, 0.16, and so on.

In some embodiments, the optical imaging system satisfies the following conditional formula: 1.3<aet14/at14<1.75;

Among them, aet14 is the sum of the air gaps of the first lens to the fourth lens with the largest effective semi-aperture in the direction of the optical axis; at14 is the sum of the air gaps of the first lens to the fourth lens on the optical axis . That is, aet14/at14 can be any value within the range of (1.3, 1.75), for example, the value can be 1.35, 1.42, 1.43, 1.44, 1.63, 1.67 and so on.

By satisfying the limitation of the conditional expression and reasonably controlling the above ratio, it is beneficial to shorten the total length of the system, and make each lens in the front lens group have a reasonable air gap at the optical axis and the maximum effective semi-aperture. In this way, the distance between the lenses is not It will be too small to increase the difficulty of lens assembly; the distance will not be too large so that the light cannot be reasonably transitioned, and the total optical length cannot be further compressed. When aet14/at14≥1.75, the air gap between the adjacent lenses of the front lens group at the maximum effective semi-aperture is too large, which will lead to a larger difference in the thickness of the lens and the thickness of the lens, uneven distribution of lens thickness, and reduced lens stability. During the assembly process of the lens, the thin part is easy to be broken, which increases the production cost; when aet14/at14≤1.3, the lens arrangement is too tight, and the assembly process is easy to squeeze, which increases the difficulty of assembly.

first embodiment

Referring to FIGS. 1 and 2 , the optical imaging system of the first embodiment sequentially includes, from the object side to the image side, a first lens 1 having a positive refractive power, and the first lens 1 has a first lens 1 with positive refractive power. The object side S2 is convex at the near optical axis, and the image side S3 of the first lens 1 is concave at the near optical axis; the second lens 2 with negative refractive power, the object side S4 of the second lens 2 It is a convex surface at the near optical axis, and the image side S5 of the second lens 2 is a concave surface at the near optical axis; the third lens 3 with positive refractive power, the object side S6 of the third lens 3 is on the near optical axis. The place is a convex surface, and the image side S7 of the third lens 3 is concave at the near optical axis; the fourth lens 4 with negative refractive power, the image side S9 of the fourth lens 4 is concave at the near optical axis. , the object side S8 of the fourth lens 4 is convex at the near optical axis; the fifth lens 5 with negative refractive power, the object side S11 of the fifth lens 5 is concave at the near optical axis, the The image side S12 of the fifth lens 5 is convex at the near optical axis; the sixth lens 6 with positive refractive power, the object side S13 of the sixth lens 6 is concave at the near optical axis, and the sixth lens 6 The image side S14 is convex at the near optical axis; the seventh lens 7 with negative refractive power, the object side S15 of the seventh lens 7 is concave at the near optical axis; the image side of the seventh lens 7 S16 is concave at the near optical axis; the eighth lens 8 with positive refractive power, the object side S17 of the eighth lens 8 is convex at the near optical axis; the image side S18 of the eighth lens 8 is at the low beam The axis is convex; the ninth lens 9 with negative refractive power, the object side S19 of the ninth lens 9 is convex at the near optical axis, and the image side S20 of the ninth lens 9 is at the near optical axis. Concave.

In addition, the object side S2 of the first lens 1 is concave at the circumference, the image side S3 of the first lens 1 is convex at the circumference; the object side S4 of the second lens 2 is concave at the circumference, and the image side S5 of the second lens 2 It is concave at the circumference; the object side S6 of the third lens 3 is concave at the circumference, and the image side S7 of the third lens 3 is convex at the circumference; the object side S8 of the fourth lens 4 is convex at the circumference, and the fourth lens is convex at the circumference. 4. The image side S9 is convex at the circumference; the object side S11 of the fifth lens 5 is concave at the circumference, the image side S12 of the fifth lens 5 is concave at the circumference; the object side S13 of the sixth lens 6 is convex at the circumference , the image side S14 of the sixth lens 6 is concave at the circumference; the object side S15 of the seventh lens 7 is convex at the circumference, and the seventh lens 7 is concave as the side S16 at the circumference; the object side S17 of the eighth lens 8 is at The circumference is convex, the image side S18 of the eighth lens 8 is concave at the circumference; the object side S19 of the ninth lens 9 is convex at the circumference, and the image side S20 of the ninth lens 9 is convex at the circumference.

From left to right in FIG. 2 are respectively the longitudinal spherical aberration curve, astigmatism curve and distortion diagram of the optical imaging system in the first embodiment; in the longitudinal spherical aberration curve, the ordinate is normalized Field of view, it can be seen from the figure that the focus deviation of each field of view is within ±0.05mm, indicating that the spherical aberration of the optical imaging system is small; in the astigmatism curve, the ordinate is the image height, the unit is mm, from It can be seen from the figure that the focus deviation of the respective fields of view of the sagittal image plane S and the meridional image plane T is within ±0.05mm, indicating that the field curvature aberration of the optical imaging system is small; in the distortion diagram, the ordinate is The image height is in mm. It can be seen from the figure that the distortion rate of each field of view is within ±2.5%, indicating that the imaging distortion of the optical imaging system is small. The astigmatism curve and distortion curve are the reference wavelength at 555nm. Therefore, it can be seen from FIG. 2 that various aberrations of the optical imaging system in the first embodiment are relatively small, so that the imaging quality is high and the imaging effect is excellent.

In the first embodiment, the effective focal length of the optical imaging system is EFL 7.28mm, the maximum field angle FOV is 49.05°, the aperture number FNO is 2.4, and the total length TTL is 7.15mm.

The reference wavelength of the focal length of the lens in the first embodiment is 555 nm, the reference wavelength of the refractive index and Abbe number is 587.56 nm, and the numerical units of Y radius, thickness and focal length are all millimeters (mm). And the optical imaging system in the first embodiment satisfies the conditions of the following table.

Table 1

It should be noted that FNO is the aperture number of the optical imaging system, and FOV is the maximum field angle of the optical imaging system.

Table 2 below shows the aspheric coefficients of the corresponding lens surfaces in Table 1, where K is the conic coefficient and Ai is the coefficient corresponding to the i-th higher-order term in the aspheric surface type formula.

Second Embodiment

Referring to FIGS. 3 and 4 ; the optical imaging system of the second embodiment includes sequentially from the object side to the image side, and sequentially includes, from the object side to the image side, a first lens 1 with positive refractive power, and the first lens 1 has a The object side S2 is convex at the near optical axis, and the image side S3 of the first lens 1 is concave at the near optical axis; the second lens 2 with negative refractive power, the object side S4 of the second lens 2 It is a convex surface at the near optical axis, and the image side S5 of the second lens 2 is a concave surface at the near optical axis; the third lens 3 with positive refractive power, the object side S6 of the third lens 3 is on the near optical axis. The place is a convex surface, and the image side S7 of the third lens 3 is a concave surface at the near optical axis; the fourth lens 4 with negative refractive power, the object side S8 of the fourth lens 4 is a convex surface at the near optical axis , the image side S9 of the fourth lens 4 is concave at the near optical axis; the fifth lens 5 with negative refractive power, the object side S11 of the fifth lens 5 is concave at the near optical axis, and the The image side S12 of the fifth lens 5 is convex at the near optical axis; the sixth lens 6 with positive refractive power, the object side S13 of the sixth lens 6 is concave at the near optical axis, and the sixth lens 6 The image side S14 is convex at the near optical axis; the seventh lens 7 with negative refractive power, the object side S15 of the seventh lens 7 is concave at the near optical axis, and the image side of the seventh lens 7 S16 is concave at the near optical axis; for the eighth lens 8 with positive refractive power, the object side S17 of the eighth lens 8 is convex at the near optical axis, and the image side S18 of the eighth lens 8 is at the low beam The axis is concave; the ninth lens 9 with positive refractive power, the object side S19 of the ninth lens 9 is convex at the near optical axis, and the image side S20 of the ninth lens 9 is concave at the near optical axis .

In addition, the object side S2 of the first lens 1 is concave at the circumference, the image side S3 of the first lens 2 is convex at the circumference; the object side S4 of the second lens 2 is convex at the circumference, and the image side S5 of the second lens 2 It is concave at the circumference; the object side S6 of the third lens 3 is concave at the circumference, and the image side S7 of the third lens 3 is concave at the circumference; the object side S8 of the fourth lens 4 is convex at the circumference, and the fourth lens 4. The image side S9 is convex at the circumference; the object side S11 of the fifth lens 5 is concave at the circumference, the image side S12 of the fifth lens 5 is concave at the circumference; the object side S13 of the sixth lens 6 is convex at the circumference , the image side S14 of the sixth lens 6 is concave at the circumference; the object side S15 of the seventh lens 7 is convex at the circumference, and the seventh lens 7 is concave as the side S16 at the circumference; the object side S17 of the eighth lens 8 is at The circumference is concave, the image side S18 of the eighth lens 8 is convex at the circumference; the object side S19 of the ninth lens 9 is convex at the circumference, and the image side S20 of the ninth lens 9 is convex at the circumference.

It can be seen from the aberration diagram in FIG. 4 that the longitudinal spherical aberration, field curvature and distortion of the optical system are well controlled, so that the optical system of this embodiment has good imaging quality. In the second embodiment, the effective focal length of the optical imaging system is EFL of 7.27mm, the maximum field of view FOV is 49.11°, the aperture number FNO is 2.19, and the total length TTL is 7.15mm.

In the second embodiment, the reference wavelength of the focal length of the lens is 555 nm, the reference wavelength of the refractive index and Abbe number is 587.56 nm, and the numerical units of Y radius, thickness and focal length are all millimeters (mm). And the optical imaging system in the second embodiment satisfies the conditions of the following table.

table 3

It should be noted that FNO is the aperture number of the optical imaging system, and FOV is the maximum field angle of the optical imaging system.

Table 4 below shows the aspheric coefficients of the corresponding lens surfaces in Table 3, where K is the conic coefficient, and Ai is the coefficient corresponding to the i-th higher-order term in the aspheric type formula.

Third Embodiment

5 and 6 , the optical imaging system of the third embodiment sequentially includes, from the object side to the image side, a first lens 1 having a positive refractive power, and the first lens 1 has a first lens 1 having a positive refractive power. The object side S2 is convex at the near optical axis, and the image side S3 of the first lens 1 is concave at the near optical axis; the second lens 2 with negative refractive power, the object side S4 of the second lens 2 It is a convex surface at the near optical axis, and the image side S5 of the second lens 2 is a concave surface at the near optical axis; the third lens 3 with positive refractive power, the object side S6 of the third lens 3 is on the near optical axis. The place is a convex surface, and the image side S7 of the third lens 3 is a concave surface at the near optical axis; the fourth lens 4 with negative refractive power, the object side S8 of the fourth lens 4 is a convex surface at the near optical axis , the image side S9 of the fourth lens 4 is concave at the near optical axis; the fifth lens 5 with negative refractive power, the object side S11 of the fifth lens 5 is concave at the near optical axis, and the The image side S12 of the fifth lens 5 is convex at the near optical axis; the sixth lens 6 with positive refractive power, the object side S13 of the sixth lens 6 is concave at the near optical axis, and the sixth lens 6 The image side S14 is convex at the near optical axis; the seventh lens 7 with negative refractive power, the object side S15 of the seventh lens 7 is concave at the near optical axis, and the image side of the seventh lens 7 S16 is concave at the near optical axis; for the eighth lens 8 with positive refractive power, the object side S17 of the eighth lens 8 is convex at the near optical axis, and the image side S18 of the eighth lens 8 is at the low beam The axis is concave; the ninth lens 9 with negative refractive power, the object side S19 of the ninth lens 9 is convex at the near optical axis, and the image side S20 of the ninth lens 9 is at the near optical axis. Concave.

In addition, the object side S2 of the first lens 1 is concave at the circumference, the image side S3 of the first lens 1 is convex at the circumference; the object side S4 of the second lens 2 is concave at the circumference, and the image side S5 of the second lens 2 It is convex at the circumference; the object side S6 of the third lens 3 is concave at the circumference, and the image side S7 of the third lens 3 is convex at the circumference; the object side S8 of the fourth lens 4 is convex at the circumference, and the fourth lens is convex at the circumference. 4. The image side S9 is concave at the circumference; the object side S11 of the fifth lens 5 is concave at the circumference, the image side S12 of the fifth lens 5 is convex at the circumference; the object side S13 of the sixth lens 6 is convex at the circumference , the image side S14 of the sixth lens 6 is concave at the circumference; the object side S15 of the seventh lens 7 is convex at the circumference, and the image side S16 of the seventh lens 8 is concave at the circumference; the object side S17 of the eighth lens 8 is at The circumference is concave, the image side S18 of the eighth lens 8 is convex at the circumference; the object side S19 of the ninth lens 9 is concave at the circumference, and the image side S20 of the ninth lens 9 is convex at the circumference.

It can be seen from the aberration diagram in FIG. 6 that the longitudinal spherical aberration, field curvature and distortion of the optical system are well controlled, so that the optical system of this embodiment has good imaging quality. In the third embodiment, the effective focal length of the optical imaging system is EFL 7.19mm, the maximum field of view FOV is 49.57°, the aperture number FNO is 2.11, and the total length TTL is 7.14mm.

The reference wavelength of the focal length of the lens of the third embodiment is 555 nm, the reference wavelength of the refractive index and Abbe number is 587.56 nm, and the numerical units of Y radius, thickness and focal length are all millimeters (mm). And the optical imaging system in the third embodiment satisfies the conditions of the following table.

table 5

It should be noted that FNO is the aperture number of the optical imaging system, and FOV is the maximum field angle of the optical imaging system.

Table 6 below shows the aspheric coefficients of the corresponding lens surfaces in Table 5, where K is the conic coefficient and Ai is the coefficient corresponding to the i-th higher-order term in the aspheric type formula.

Fourth Embodiment

Referring to FIGS. 7 and 8 ; the optical imaging system of the fourth embodiment includes sequentially from the object side to the image side, and sequentially includes, from the object side to the image side, a first lens 1 with positive refractive power, and the first lens 1 has a The object side S2 is convex at the near optical axis, and the image side S3 of the first lens 1 is concave at the near optical axis; the second lens 2 with negative refractive power, the object side S4 of the second lens 2 It is a convex surface at the near optical axis, and the image side S5 of the second lens 2 is a concave surface at the near optical axis; the third lens 3 with positive refractive power, the object side S6 of the third lens 3 is on the near optical axis. The place is a convex surface, and the image side S7 of the third lens 3 is a concave surface at the near optical axis; the fourth lens 4 with positive refractive power, the object side S8 of the fourth lens 4 is a convex surface at the near optical axis, The image side S9 of the fourth lens 4 is concave at the near optical axis; for the fifth lens 5 with positive refractive power, the object side S11 of the fifth lens 5 is concave at the near optical axis, and the fifth lens 5 is concave at the near optical axis. The image side S12 of the lens 5 is convex at the near optical axis; for the sixth lens 6 with negative refractive power, the object side S13 of the sixth lens 6 is concave at the near optical axis, and the sixth lens 6 has a concave surface. The image side S14 is convex at the near optical axis; the seventh lens 7 with negative refractive power, the object side S15 of the seventh lens 7 is convex at the near optical axis, and the image side S16 of the seventh lens 7 It is a concave surface at the near optical axis; the eighth lens 8 with positive refractive power, the object side S17 of the eighth lens 8 is convex at the near optical axis, and the image side S18 of the eighth lens 8 is on the near optical axis. The place is a concave surface; the ninth lens 9 with negative refractive power, the object side S19 of the ninth lens 9 is a convex surface at the near optical axis, and the image side S20 of the ninth lens 9 is a concave surface at the near optical axis .

In addition, the object side S2 of the first lens 1 is concave at the circumference, the image side S3 of the first lens 1 is convex at the circumference; the object side S4 of the second lens 2 is convex at the circumference, and the image side S5 of the second lens 2 It is concave at the circumference; the object side S6 of the third lens 3 is concave at the circumference, and the image side S7 of the third lens 3 is convex at the circumference; the object side S8 of the fourth lens 4 is convex at the circumference, and the fourth lens is convex at the circumference. 4. The image side S9 is convex at the circumference; the object side S11 of the fifth lens 5 is concave at the circumference, the fifth lens 5 image side S12 is convex at the circumference; the object side S13 of the sixth lens 6 is concave at the circumference , the image side S14 of the sixth lens 6 is concave at the circumference; the object side S15 of the seventh lens 7 is convex at the circumference, and the seventh lens 7 is concave as the side S16 at the circumference; the object side S17 of the eighth lens 8 is at The circumference is convex, the image side S18 of the eighth lens 8 is concave at the circumference; the object side S19 of the ninth lens 9 is convex at the circumference, and the image side S20 of the ninth lens 9 is convex at the circumference.

It can be seen from the aberration diagram in FIG. 8 that the longitudinal spherical aberration, field curvature and distortion of the optical system are well controlled, so that the optical system of this embodiment has good imaging quality. In the fourth embodiment, the effective focal length of the optical imaging system is EFL 7.28mm, the maximum field of view FOV is 49.89°, the aperture number FNO is 2.30, and the total length TTL is 7.13mm.

In the fourth embodiment, the reference wavelength of the focal length of the lens is 555 nm, the reference wavelength of the refractive index and Abbe number is 587.56 nm, and the numerical units of Y radius, thickness and focal length are all millimeters (mm). And the optical imaging system in the fourth embodiment satisfies the conditions of the following table.

Table 7

It should be noted that FNO is the aperture number of the optical imaging system, and FOV is the maximum field angle of the optical imaging system.

The following Table 8 shows the aspheric coefficients of the lens surface in Table 7, where K is the conic coefficient, and Ai is the coefficient corresponding to the i-th higher-order term in the aspheric type formula.

Fifth Embodiment

Referring to FIGS. 9 and 10 ; the optical imaging system of the fifth embodiment includes sequentially from the object side to the image side, and sequentially includes, from the object side to the image side, a first lens 1 with positive refractive power, and the first lens 1 has a The object side S2 is convex at the near optical axis, and the image side S3 of the first lens 1 is concave at the near optical axis; the second lens 2 with negative refractive power, the object side S4 of the second lens 2 It is a convex surface at the near optical axis, and the image side S5 of the second lens 2 is a concave surface at the near optical axis; the third lens 3 with positive refractive power, the object side S6 of the third lens 3 is on the near optical axis. The place is a convex surface, and the image side S7 of the third lens 3 is a concave surface at the near optical axis; the fourth lens 4 with positive refractive power, the object side S8 of the fourth lens 4 is a convex surface at the near optical axis, The image side S9 of the fourth lens 4 is concave at the near optical axis; for the fifth lens 5 with negative refractive power, the object side S11 of the fifth lens 5 is concave at the near optical axis, and the fifth lens 5 is concave at the near optical axis. The image side S12 of the five-lens 5 is convex at the near optical axis; the sixth lens 6 with negative refractive power, the object side S13 of the sixth lens 6 is concave at the near optical axis, and the sixth lens 6 The image side S14 is convex at the near optical axis; the seventh lens 7 with negative refractive power, the object side S15 of the seventh lens 7 is convex at the near optical axis, and the image side of the seventh lens 7 S16 is concave at the near optical axis; for the eighth lens 8 with positive refractive power, the object side S17 of the eighth lens 8 is convex at the near optical axis, and the image side S18 of the eighth lens 8 is at the low beam The axis is concave; the ninth lens 9 with negative refractive power, the object side S19 of the ninth lens 9 is convex at the near optical axis, and the image side S20 of the ninth lens 9 is at the near optical axis. Concave.

In addition, the object side S2 of the first lens 1 is concave at the circumference, the image side S3 of the first lens 1 is convex at the circumference; the object side S4 of the second lens 2 is concave at the circumference, and the image side S5 of the second lens 2 It is convex at the circumference; the object side S6 of the third lens 3 is concave at the circumference, and the image side S7 of the third lens 3 is convex at the circumference; the object side S8 of the fourth lens 4 is convex at the circumference, and the fourth lens is convex at the circumference. 4. The image side S9 is concave at the circumference; the object side S11 of the fifth lens 5 is concave at the circumference, the fifth lens 5 image side S12 is convex at the circumference; the object side S13 of the sixth lens 6 is concave at the circumference , the image side S14 of the sixth lens 6 is concave at the circumference; the object side S15 of the seventh lens 7 is concave at the circumference, and the seventh lens 7 image side S16 is convex at the circumference; the object side S17 of the eighth lens 8 is at The circumference is concave, the image side S18 of the eighth lens 8 is convex at the circumference; the object side S19 of the ninth lens 9 is convex at the circumference, and the image side S20 of the ninth lens 9 is concave at the circumference.

It can be seen from the aberration diagram in FIG. 10 that the longitudinal spherical aberration, field curvature and distortion of the optical system are well controlled, so that the optical system of this embodiment has good imaging quality. In the fifth embodiment, the effective focal length of the optical imaging system is EFL 7.27mm, the maximum field angle FOV is 48.91°, the aperture number FNO is 2.30, and the total length TTL is 6.95mm.

In the fifth embodiment, the reference wavelength of the focal length of the lens is 555 nm, the reference wavelength of the refractive index and Abbe number is 587.56 nm, and the numerical units of Y radius, thickness and focal length are all millimeters (mm). And the optical imaging system in the fifth embodiment satisfies the conditions of the following table.

Table 9

It should be noted that FNO is the aperture number of the optical imaging system, and FOV is the maximum field angle of the optical imaging system.

Table 10 below shows the aspheric coefficients of the corresponding lens surfaces in Table 9, where K is the conic coefficient, and Ai is the coefficient corresponding to the i-th higher-order term in the aspheric surface type formula.

Sixth Embodiment

Referring to FIGS. 11 and 12 ; the optical imaging system of the sixth embodiment includes sequentially from the object side to the image side, and sequentially includes, from the object side to the image side, a first lens 1 with positive refractive power, and the first lens 1 has a The object side S2 is convex at the near optical axis, and the image side S3 of the first lens 1 is concave at the near optical axis; the second lens 2 with negative refractive power, the object side S4 of the second lens 2 It is a convex surface at the near optical axis, and the image side S5 of the second lens 2 is a concave surface at the near optical axis; the third lens 3 with positive refractive power, the object side S6 of the third lens 3 is on the near optical axis. The place is a convex surface, and the image side S7 of the third lens 3 is concave at the near optical axis; the fourth lens 4 with negative refractive power, the object side S8 of the fourth lens 4 is concave at the near optical axis. , the image side S9 of the fourth lens 4 is concave at the near optical axis; the fifth lens 5 with negative refractive power, the object side S11 of the fifth lens 5 is concave at the near optical axis, and the The image side S12 of the fifth lens 5 is convex at the near optical axis; the sixth lens 6 with positive refractive power, the object side S13 of the sixth lens 6 is concave at the near optical axis, and the sixth lens 6 The image side S14 is convex at the near optical axis; the seventh lens 7 with negative refractive power, the object side S15 of the seventh lens 7 is concave at the near optical axis, and the image side of the seventh lens 7 S16 is concave at the near optical axis; for the eighth lens 8 with negative refractive power, the object side S17 of the eighth lens 8 is convex at the near optical axis, and the image side S18 of the eighth lens 8 is near the The optical axis is a concave surface; the ninth lens 9 with positive refractive power, the object side S19 of the ninth lens 9 is a convex surface at the near optical axis, and the image side S20 of the ninth lens 9 is at the near optical axis. Concave.

In addition, the object side S2 of the first lens 1 is concave at the circumference, the image side S3 of the first lens 1 is convex at the circumference; the object side S4 of the second lens 2 is concave at the circumference, and the image side S5 of the second lens 2 It is convex at the circumference; the object side S6 of the third lens 3 is concave at the circumference, and the image side S7 of the third lens 3 is concave at the circumference; the object side S8 of the fourth lens 4 is convex at the circumference, and the fourth lens 4. The image side S9 is convex at the circumference; the object side S11 of the fifth lens 5 is concave at the circumference, the image side S12 of the fifth lens 5 is convex at the circumference; the object side S13 of the sixth lens 6 is convex at the circumference , the image side S14 of the sixth lens 6 is concave at the circumference; the object side S15 of the seventh lens 7 is convex at the circumference, and the seventh lens 7 is convex at the circumference as the side S16; the object side S17 of the eighth lens 8 is at The circumference is concave, the image side S18 of the eighth lens 8 is convex at the circumference; the object side S19 of the ninth lens 9 is convex at the circumference, and the image side S20 of the ninth lens 9 is convex at the circumference.

It can be seen from the aberration diagram in FIG. 12 that the longitudinal spherical aberration, field curvature and distortion of the optical system are well controlled, so that the optical system of this embodiment has good imaging quality. In the sixth embodiment, the effective focal length of the optical imaging system is EFL 7.28mm, the maximum field of view FOV is 48.69°, the aperture number FNO is 2.21, and the total length TTL is 7.14mm.

The reference wavelength of the focal length of the sixth embodiment lens is 555 nm, the reference wavelength of the refractive index and Abbe number is 587.56 nm, and the numerical units of Y radius, thickness and focal length are all millimeters (mm). And the optical imaging system in the sixth embodiment satisfies the conditions of the following table.

Table 11

It should be noted that FNO is the aperture number of the optical imaging system, and FOV is the maximum field angle of the optical imaging system.

The following Table 12 shows the aspheric coefficients of the corresponding lens surfaces in Table 11, where K is the conic coefficient, and Ai is the coefficient corresponding to the i-th higher-order term in the aspheric surface type formula.

The above-mentioned Embodiments 1 to 6 satisfy the relational expressions described in Table 13:

Conditional Expression/Example	1	2	3	4	5	6
6<f2/(r22-r21)<14.5	10.976	11.572	9.107	6.458	7.014	14.057
15<f7/sag72<120	54.359	50.383	26.304	116.770	19.210	25.234
15<r81/|sag81|<135	123.71	122.90	47.62	60.51	21.97	131.17
EFL/TTL>1	1.02	1.02	1.01	1.02	1.05	1.02
f1/sd11<4.2	3.96	3.94	3.81	4.10	4.11	3.96
0.32<BFL/sd92<0.4	0.36	0.34	0.37	0.36	0.38	0.36
IMGH*2/TTL>0.93	0.937	0.937	0.938	0.939	0.964	0.938
tan(FOV/2)/ct19>0.12mm -1	0.13	0.12	0.13	0.13	0.16	0.14
1.3<aet14/at14<1.75	1.63	1.71	1.43	1.44	1.42	1.35

The present application also provides an imaging module, including any one of the optical systems, and having good imaging quality.

The present application also provides an electronic device, comprising a casing and the above-mentioned imaging module. The imaging module is arranged in the casing. By using the above-mentioned imaging module, the electronic device can have good imaging performance.

The above are only specific embodiments of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can easily think of changes or replacements within the technical scope disclosed in the present application, and should cover within the scope of protection of this application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims (12)

1. An optical imaging system, characterized in that, from the object side to the image side, it comprises:

   The first lens with positive refractive power, the object side of the first lens is convex at the near optical axis, and the image side of the first lens is concave at the near optical axis;

   The second lens with negative refractive power, the object side of the second lens is convex at the near optical axis, and the image side of the second lens is concave at the near optical axis;

   a third lens with positive refractive power, the object side of the third lens is convex at the near optical axis;

   a fourth lens with optical power, wherein the image side surface of the fourth lens is concave at the near optical axis;

   The fifth lens with optical power, the object side of the fifth lens is concave at the near optical axis, and the image side of the fifth lens is convex at the near optical axis;

   The sixth lens with optical power, the object side of the sixth lens is concave at the near optical axis, and the image side of the sixth lens is convex at the near optical axis;

   a seventh lens with negative refractive power, the image side of the seventh lens is concave at the near optical axis;

   an eighth lens with optical power, the object side of the eighth lens is convex at the near optical axis;

   A ninth lens with optical power, the object side of the ninth lens is convex at the near optical axis, and the image side of the ninth lens is concave at the near optical axis.
2. The optical imaging system according to claim 1, wherein the optical imaging system satisfies the following conditional formula:

   6<f2/(r22-r21)<14.5;

   Wherein, f2 is the effective focal length of the second lens; r22 is the radius of curvature of the image side of the second lens at the optical axis; r21 is the radius of curvature of the object side of the second lens at the optical axis.
3. The optical imaging system according to claim 1, wherein the optical imaging system satisfies the following conditional formula:

   15<f7/sag72<120;

   Wherein, f7 is the effective focal length of the seventh lens; sag72 is the sagittal height of the image side surface of the seventh lens at the maximum effective diameter.
4. The optical imaging system according to claim 1, wherein the optical imaging system satisfies the following conditional formula:

   15<r81/|sag81|<135;

   Wherein, r81 is the radius of curvature of the object side of the eighth lens at the optical axis; sag81 is the sag of the object side of the eighth lens at the maximum effective diameter.
5. The optical imaging system according to claim 1, wherein the optical imaging system satisfies the following conditional formula:

   EFL/TTL>1;

   Wherein, EFL is the effective focal length of the optical imaging system, and TTL is the distance on the optical axis from the object side of the first lens to the imaging surface of the optical system.
6. The optical imaging system according to claim 1, wherein the optical imaging system satisfies the following conditional formula:

   f1/sd11<4.2;

   Wherein, f1 is the effective focal length of the first lens; sd11 is the maximum effective semi-aperture of the object side of the first lens.
7. The optical imaging system according to claim 1, wherein the optical imaging system satisfies the following conditional formula:

   0.32<BFL/sd92<0.4;

   Wherein, BFL is the minimum distance from the image side of the ninth lens to the imaging plane of the optical imaging system in the direction of the optical axis; sd92 is the maximum effective half-aperture of the image side of the ninth lens.
8. The optical imaging system according to claim 1, wherein the optical imaging system satisfies the following conditional formula:

   IMGH*2/TTL>0.93;

   Wherein, TTL is the distance from the object side of the first lens to the imaging plane of the optical system on the optical axis; ImgH is the half of the image height corresponding to the maximum angle of view of the optical system.
9. The optical imaging system according to claim 1, wherein the optical imaging system satisfies the following conditional formula:

   tan(FOV/2)/ct19>0.12mm ^-1 ;

   Wherein, FOV is the maximum angle of view of the optical imaging system; ct19 is the sum of the thicknesses of the first lens to the ninth lens on the optical axis.
10. The optical imaging system according to claim 1, wherein the optical imaging system satisfies the following conditional formula:

    1.3<aet14/at14<1.75;

    Wherein, aet14 is the sum of the air gaps of the first lens to the fourth lens with the largest effective semi-aperture in the direction of the optical axis; at14 is the sum of the air gaps of the first lens to the fourth lens on the optical axis .
11. An imaging module, comprising: the optical imaging system according to any one of claims 1 to 10.
12. An electronic device, comprising: a casing and the imaging module according to claim 11, wherein the imaging module is mounted on the casing.

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