CN117518404A

CN117518404A - Optical imaging system, camera module and electronic equipment

Info

Publication number: CN117518404A
Application number: CN202311490505.6A
Authority: CN
Inventors: 陈嘉伟; 韦怡
Original assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Current assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Priority date: 2023-11-09
Filing date: 2023-11-09
Publication date: 2024-02-06

Abstract

The application provides an optical imaging system, a camera module and electronic equipment. The optical imaging system of the application includes a lens group including a lens group sequentially arranged from an object side to an image side: a first lens having optical power, the first lens having a first object-side surface; a second lens having optical power; a third lens having optical power; and wherein the optical imaging system further has an imaging surface, the optical imaging system satisfying the following conditional expression: BFL/TTL is more than or equal to 0.7 and less than or equal to 0.9; wherein BFL is a back focal length of the optical imaging system, and TTL is an on-optical distance from the first object side surface of the first lens to the imaging surface of the optical imaging system. The optical imaging system of the present application has a small volume.

Description

Optical imaging system, camera module and electronic equipment

Technical Field

The application relates to the field of optics, in particular to an optical imaging system, a camera module and electronic equipment.

Background

With the development of camera technologies, imaging quality requirements of camera modules are higher and higher, however, the existing optical imaging system still cannot well meet the requirements of consumers.

Disclosure of Invention

In a first aspect, the present application provides an optical imaging system comprising a lens group comprising, in order from an object side to an image side:

a first lens having optical power, the first lens having a first object-side surface;

a second lens having optical power;

a third lens having optical power; and

the optical imaging system also has an imaging surface, and the optical imaging system meets the following conditional expression:

0.7≤BFL/TTL≤0.9；

wherein BFL is a back focal length of the optical imaging system, and TTL is an on-optical distance from the first object side surface of the first lens to the imaging surface of the optical imaging system.

In a second aspect, the present application provides a camera module, comprising:

a lens barrel;

the optical imaging system of the embodiment of the application is accommodated in the lens barrel; and

And the photosensitive element is positioned on the image side of the optical imaging system.

In a third aspect, the present application provides an electronic device, comprising:

the camera module set is described in the embodiment of the application; and

and the processor is electrically connected with the photosensitive element of the camera module and used for controlling the photosensitive element to convert image signals projected by the optical imaging system into electric signals.

The optical imaging system of this application embodiment includes first lens, second lens and the third lens of arranging in proper order along the optical axis, and satisfies 0.7 and be less than or equal to BFL/TTL and be less than or equal to 0.9, this makes the optical imaging system of this application have sufficient back focal length, can set up the prism between optical imaging system's last lens and imaging surface, turns and folds the light ray, can make the camera module that adopts this optical imaging system have less volume, has higher imaging quality simultaneously.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings can be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic structural diagram of an optical imaging system according to an embodiment of the present application.

Fig. 2 is a schematic structural view of an optical imaging system according to still another embodiment of the present application.

Fig. 3 is a schematic structural view of an optical imaging system according to still another embodiment of the present application.

Fig. 4 is a schematic structural view of an optical imaging system according to still another embodiment of the present application.

Fig. 5 is a schematic optical path diagram of an optical imaging system according to an embodiment of the present application, wherein a dashed line is a light path.

Fig. 6 is a schematic structural diagram of an optical imaging system according to embodiment 1 of the present application, in which a flat glass is disposed between a fourth lens and a protective sheet in the optical imaging system during testing.

Fig. 7 is a spot diagram of the optical imaging system of embodiment 1 of the present application.

Fig. 8 is an astigmatism and distortion graph of the optical imaging system of embodiment 1 of the present application.

Fig. 9 is a schematic structural diagram of an optical imaging system according to embodiment 2 of the present application, in which a prism portion in the optical imaging system is tested using a flat glass with an equivalent optical path length.

Fig. 10 is a spot diagram of the optical imaging system of embodiment 2 of the present application.

Fig. 11 is an astigmatism and distortion graph of the optical imaging system of embodiment 2 of the present application.

Fig. 12 is a schematic structural diagram of an optical imaging system according to embodiment 3 of the present application, in which a prism portion in the optical imaging system is tested using a flat glass with an equivalent optical path length.

Fig. 13 is a spot diagram of an optical imaging system of embodiment 3 of the present application.

Fig. 14 is an astigmatism and distortion graph of the optical imaging system of embodiment 3 of the present application.

Fig. 15 is a schematic structural diagram of a camera module according to an embodiment of the present application.

Fig. 16 is a schematic structural diagram of an electronic device according to an embodiment of the present application.

Fig. 17 is an exploded view of an electronic device according to an embodiment of the present disclosure.

Fig. 18 is a circuit block diagram of an electronic device provided in an embodiment of the present application.

Reference numerals illustrate:

100-optical imaging system, L0-stop, L10-lens group, 10-first lens, 11-first object side, 12-first image side, 20-second lens, 21-second object side, 22-second image side, 30-third lens, 31-third object side, 32-third image side, 40-fourth lens, 41-fourth object side, 42-fourth image side, 50-prism, 50 a-sheet glass, 51-first reflecting surface, 52-first light surface, 521-incident area, 522-exit area, 53-second reflecting surface, 54-second light surface, 60-protective sheet, 61-fifth object side, 62-fifth image side, 70-imaging surface, 200-camera module, 210-barrel, 220-photosensitive element, 300-electronic device, 310-processor, 320-memory, 330-display screen, 340-middle frame, 350-housing.

Detailed Description

In order to make the present application solution better understood by those skilled in the art, the following description will clearly and completely describe the technical solution in the embodiments of the present application with reference to the accompanying drawings in the embodiments of the present application, and it is apparent that the described embodiments are only some embodiments of the present application, not all embodiments. All other embodiments, which can be made by one of ordinary skill in the art based on the embodiments herein without making any inventive effort, are intended to be within the scope of the present application.

The terms first, second and the like in the description and in the claims of the present application and in the above-described figures, are used for distinguishing between different objects and not for describing a particular sequential order. Furthermore, the terms "comprise" and "have," as well as any variations thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, system, article, or apparatus that comprises a list of steps or elements is not limited to only those listed steps or elements but may include other steps or elements not listed or inherent to such process, method, article, or apparatus.

The technical solutions in the embodiments of the present application will be described below with reference to the accompanying drawings.

It should be noted that, for convenience of explanation, in the embodiments of the present application, like reference numerals denote like components, and for brevity, detailed explanation of the like components is omitted in different embodiments.

The ultra-long focal lens of portable electronic equipment such as mobile phones is basically of periscope type structure. The periscope type lens has large volume, and is difficult to realize a large aperture in the limited space of the mobile phone. When the lens is matched with a large image plane for use, the lens is arranged along the thickness direction of the mobile phone, and the size of the lens is limited by the thickness of the mobile phone, so that the lens usually adopts a lens trimming scheme, and the reliability and the parasitic light performance of the lens are poor.

Referring to fig. 1, an optical imaging system 100 is provided in an embodiment of the present application, where the optical imaging system 100 includes a lens group L10, and the lens group L10 includes, in order from an object side to an image side: a first lens 10 having optical power, a second lens 20 having optical power, and a third lens 30 having optical power; the first lens 10 has a first object side 11 facing away from the second lens 20, wherein the optical imaging system 100 further has an imaging surface 70, and the optical imaging system 100 satisfies the following conditional expression: BFL/TTL is more than or equal to 0.7 and less than or equal to 0.9; wherein BFL is a back focal length of the optical imaging system 100, TTL is an on-optical distance between the first object side surface 11 of the first lens element 10 and the imaging surface 70 of the optical imaging system 100, that is, TTL is an optical total length of the optical imaging system 100.

The term "focal power" in this application characterizes the ability of an optical system to deflect light.

The optical imaging system 100 has an optical axis, and the first lens 10, the second lens 20, and the third lens 30 are stacked in this order from the object side to the image side.

The "object side" refers to a side close to an object to be photographed or brought into an image along the optical axis direction, and the "image side" refers to a side close to the imaging surface 70 along the optical axis direction. It is understood that the "object side" of the present application refers to a surface of a certain lens that is close to or faces the object side in the optical axis direction.

When the optical imaging system 100 is used, light enters from the object side (i.e., the side of the first lens 10 facing away from the second lens 20), and is refracted through the first lens 10, the second lens 20 and the third lens 30 in sequence, and then is imaged on the imaging surface 70.

Specifically, the ratio BFL/TTL of the back focal length BFL of the optical imaging system 100 to the distance TTL from the first object side 11 of the first lens 10 to the imaging plane 70 of the optical imaging system 100 may be, but not limited to, 0.7, 0.71, 0.72, 0.73, 0.74, 0.75, 0.76, 0.77, 0.78, 0.79, 0.8, 0.81, 0.82, 0.83, 0.84, 0.85, 0.86, 0.87, 0.88, 0.89, 0.9, etc. If the BFL/TTL is too small, the back focal length BFL of the optical imaging system 100 is too small, so that it is difficult to set the prism 50 between the last lens of the optical imaging system 100 and the imaging surface 70, which is not beneficial to miniaturization of the camera module using the optical imaging lens; too large BFL/TTL leaves too small a volume for the lens group L10 of the optical imaging system 100, which is prone to collision between adjacent lenses, and it is difficult to guarantee the performance of the optical imaging system 100.

The optical imaging system 100 of the present application may be applied to a camera module of an electronic device having a camera function, such as a mobile phone, a tablet computer, a smart bracelet, a smart watch, smart glasses, a notebook computer, a camera, an electronic book reader, and the like.

The optical imaging system 100 of the embodiment of the application includes the first lens 10, the second lens 20 and the third lens 30 which are sequentially arranged along the optical axis, and satisfies 0.7-0.7 BFL/TTL-0.9, which makes the optical imaging system 100 of the application have a sufficient back focal length, and the prism 50 can be arranged between the last lens of the optical imaging system 100 and the imaging surface 70, so that the light is turned and folded, and the camera module adopting the optical imaging system 100 has smaller volume and higher imaging quality.

Referring to fig. 2, in some embodiments, the lens group L10 further includes a fourth lens 40 having optical power, and the fourth lens 40 is disposed between the third lens 30 and the imaging surface 70. The greater the number of lenses included in the optical imaging system 100, the better the imaging effect, and the optical imaging system 100 employing four lenses of the present embodiment has better imaging quality than the optical imaging system 100 having three lenses.

It can be understood that in the present embodiment, the optical imaging system 100 includes the first lens 10 having optical power, the second lens 20 having optical power, the third lens 30 having optical power, and the fourth lens 40 having optical power, which are arranged in this order from the object side to the image side. It can be understood that, in the present embodiment, the lens group L10 includes a first lens 10, a second lens 20, a third lens 30, and a fourth lens 40.

Alternatively, the first lens 10 may be a glass lens or a plastic lens.

Optionally, the first lens 10 has positive optical power. The first lens 10 further has a first image side 12, the first image side 12 facing the second lens 20. The first lens 10 may be a spherical lens or an aspherical lens. In other words, the first object-side surface 11 may be a spherical surface or an aspherical surface, and the first image-side surface 12 may be a spherical surface or an aspherical surface. The first object-side surface 11 may be convex at the optical axis, and the first image-side surface 12 may be convex or concave at the optical axis. The first lens 10 employs a lens having positive optical power, which is more advantageous in downsizing the optical imaging system 100.

It is understood that "image side" in this application refers to a surface of a certain lens that is close to or faces the image side in the optical axis direction.

Alternatively, the second lens 20 may be a glass lens or a plastic lens.

Optionally, the second lens 20 has positive optical power. The second lens 20 has a second object-side surface 21 and a second image-side surface 22, the second object-side surface 21 facing the first lens 10, the second image-side surface 22 facing the third lens 30. The second lens 20 is an aspherical lens. In other words, the second object-side surface 21 and the second image-side surface 22 are both aspheric. The second object-side surface 21 may be convex or concave at the optical axis, and the second image-side surface 22 may be convex or concave at the optical axis. The second lens 20 employs a lens having positive optical power, which is more advantageous in downsizing the optical imaging system 100.

Alternatively, the third lens 30 may be a glass lens or a plastic lens.

Optionally, the third lens 30 has negative optical power. The third lens element 30 has a third object-side surface 31 and a third image-side surface 32, wherein the third object-side surface 31 faces the second lens element 20 and the third image-side surface 32 faces away from the second lens element 20. The third lens 30 is an aspherical lens. In other words, the third object-side surface 31 and the third image-side surface 32 are both aspheric. The third object-side surface 31 may be convex or concave at the optical axis, and the third image-side surface 32 may be convex or concave at the optical axis. The third lens 30 employs a lens having negative optical power, which is advantageous in correcting aberrations of the optical imaging system 100.

Alternatively, the fourth lens 40 may be a glass lens or a plastic lens.

Optionally, the fourth lens 40 has negative optical power. The fourth lens element 40 has a fourth object-side surface 41 and a fourth image-side surface 42, wherein the fourth object-side surface 41 faces the third lens element 30 and the fourth image-side surface 42 faces away from the third lens element 30. The fourth lens 40 is an aspherical lens. In other words, the fourth object-side surface 41 and the fourth image-side surface 42 are both aspheric. The fourth object-side surface 41 may be convex or concave at the optical axis, and the fourth image-side surface 42 may be convex or concave at the optical axis. The fourth lens 40 employs a lens having negative optical power, which is advantageous in correcting aberrations of the optical imaging system 100.

Alternatively, the aspherical surface may satisfy, but is not limited to, the following relationship:

where z is a distance vector height from an aspherical vertex (vertex means an intersection point of the aspherical surface and the optical axis) when the aspherical surface is at a position of r in the optical axis direction, r is a distance from a point on the aspherical surface to the vertex of the aspherical surface, C is a curvature of the aspherical surface, k is a conic coefficient, a is a 4 th order correction coefficient of the aspherical surface, B is a 6 th order correction coefficient of the aspherical surface, C is an 8 th order correction coefficient of the aspherical surface, D is a 10 th order correction coefficient of the aspherical surface, E is a 12 th order correction coefficient of the aspherical surface, F is a 14 th order correction coefficient of the aspherical surface, G is a 16 th order correction coefficient of the aspherical surface, H is an 18 th order correction coefficient of the aspherical surface, and J is a 20 th order correction coefficient of the aspherical surface.

Referring to fig. 3 to 5, in some embodiments, the optical imaging system 100 further includes a prism 50, and the prism 50 is disposed between the lens group L10 of the optical imaging system 100 and the imaging surface 70.

As can be appreciated, the prism 50 is disposed between the lens group L10 and the imaging plane 70 of the optical imaging system 100.

It can also be appreciated that when the optical imaging system 100 includes the first lens 10, the second lens 20, the third lens 30 and the prism 50, the first lens 10, the second lens 20, the third lens 30 and the prism 50 are sequentially arranged along the optical axis direction, that is, the prism 50 is located between the third lens 30 and the imaging surface 70. When the optical imaging system 100 includes the first lens 10, the second lens 20, the third lens 30, the fourth lens 40 and the prism 50, the first lens 10, the second lens 20, the third lens 30, the fourth lens 40 and the prism 50 are sequentially arranged along the optical axis direction, that is, the prism 50 is located between the fourth lens 40 and the imaging surface 70.

In this embodiment, by disposing the prism 50 between the last lens of the optical imaging system 100 and the imaging surface 70, the prism 50 can turn and fold the light, thereby reducing the size of the optical imaging system 100, which is beneficial to shortening the length of the optical imaging system 100, so that the camera module using the optical imaging system 100 has a shorter length. In addition, adding prism 50 to optical imaging system 100 provides better imaging quality.

In one embodiment, the optical imaging system 100 is composed of three lenses and one prism 50, i.e., the lens group L10 is composed of three lenses. In other words, in the present embodiment, the optical imaging system 100 includes the first lens 10, the second lens 20, the third lens 30 and the prism 50 from the object side to the image side. The first object-side surface 11 and the first image-side surface 12 of the first lens element 10 are spherical surfaces, and the second object-side surface 21, the second image-side surface 22, the third object-side surface 31 and the third image-side surface 32 are aspheric surfaces.

In yet another embodiment, the optical imaging system 100 is composed of four lenses and one prism 50, i.e., the lens group L10 is composed of four lenses. In other words, in the present embodiment, the optical imaging system 100 includes the first lens 10, the second lens 20, the third lens 30, the fourth lens 40 and the prism 50 from the object side to the image side. The first object-side surface 11 and the first image-side surface 12 of the first lens element 10 are spherical surfaces, and the second object-side surface 21, the second image-side surface 22, the third object-side surface 31, the third image-side surface 32, the fourth object-side surface 41 and the fourth image-side surface 42 are aspheric surfaces.

In some embodiments, the optical imaging system 100 also satisfies the following conditional expression:

0.7≤L/TTL≤0.78；

where L is the optical path length of the light in the prism 50.

Specifically, the L/TTL can be, but is not limited to being, 0.7, 0.71, 0.72, 0.73, 0.74, 0.75, 0.76, 0.77, 0.78, etc. The ratio of the optical path length L of the light beam in the prism 50 to the total optical length TTL of the optical imaging system 100 is too small, so that the light beam incident on the prism 50 easily exceeds the reflection area of the prism 50, which affects the imaging of the optical imaging system 100, and the ratio of the optical path length L of the light beam in the prism 50 to the total optical length TTL of the optical imaging system 100 is too large, which increases the size of the optical imaging system 100 and is not beneficial to the miniaturization of the optical imaging system 100. When the L/TTL is 0.7 to 0.78, the optical imaging system 100 can be made to have a better imaging effect, and at the same time, the optical imaging system 100 can be made to be more miniaturized.

In the present embodiment, by providing the prism 50 on the image side of the third lens 30, the prism 50 can fold the light incident on the prism 50 and fold the light in a smaller area, so that the volume of the optical imaging system 100 can be reduced, making the optical imaging system 100 more compact. In addition, the optical imaging system 100 can be provided with better imaging quality. In addition, the prism 50 is arranged between the lens group L10 and the imaging surface 70, so that when the optical imaging lens is applied to electronic equipment with a narrow thickness such as a mobile phone, the lens of the optical imaging lens can be arranged perpendicular to the thickness direction of the electronic equipment and cannot be limited by the thickness of the electronic equipment, and therefore a large aperture can be better achieved without trimming the lens.

In some embodiments, the prism 50 includes a first reflective surface 51, a first light surface 52, and a second reflective surface 53 connected in sequence, the first light surface 52 faces the lens group L10, the first reflective surface 51 and the second reflective surface 53 are disposed on a side of the first light surface 52 facing away from the lens group L10, and the light entering the prism 50 after exiting the lens group L10 sequentially passes through the first light surface 52, is reflected by the first reflective surface 51, is totally reflected by the first light surface 52, is reflected by the second reflective surface 53, and exits from the first light surface 52 for imaging.

In this embodiment, the light emitted from the image side of the lens assembly L10 enters the prism 50 through the first light surface 52 of the prism 50, then is reflected by the first light surface 52 through the first reflecting surface 51, is totally reflected by the first light surface 52 to the second reflecting surface 53, is reflected by the second reflecting surface 53 back to the first light surface 52, is emitted from the first light surface 52, and finally is imaged on the imaging surface 70.

It is understood that the light may be transmitted through the first light surface 52, and only when the light reflected by the first light surface 51 to the first light surface 52 reaches the total reflection angle, the light is totally reflected by the first light surface 52 to the second light surface 53. In order to increase the light transmittance of the first light surface 52 and improve the light output efficiency of the prism 50, an antireflection film may be coated on the first light surface 52 to reduce the reflection of the first light surface 52 to light and improve the light transmittance of the first light surface 52.

The first light surface 52 includes an incident area 521 and an exit area 522, and light enters the prism 50 from the incident area 521 and exits the prism 50 from the exit area 522. The lens group L10 is laminated and arranged corresponding to the exit area 522 of the prism 50, the imaging surface 70 corresponds to the exit area 522 of the prism 50, and the light is emitted from the exit area 522 and then imaged on the imaging surface 70.

Alternatively, the first reflecting surface 51 and the second reflecting surface 53 may be formed by plating a reflective coating on the surface of the prism 50.

In the embodiment, the prism 50 structure and the reflecting surface are arranged, so that light rays are reflected in the prism 50 for multiple times, the light rays can be folded in a smaller area, the volume of the optical imaging system 100 is better reduced, and the optical imaging system 100 is more miniaturized. In addition, the light is incident into the prism 50 from the incident area 521 of the first light surface 52, and is emitted out of the prism 50 from the emitting area 522 of the first light surface 52, so that the lens group L10 and the imaging surface 70 are located on the same side of the prism 50, and the photosensitive element (also called a photosensitive chip) of the camera module of the optical imaging system 100 and the lens group L10 can be disposed on the same side of the prism 50, which can better reduce the thickness of the camera module using the optical imaging system 100 and is more beneficial to miniaturizing the optical imaging system 100.

In some embodiments, the prism 50 is a triangular prism 50 (not shown) or a quadrangular prism 50; when the prism 50 is a triangular prism 50, a side of the first reflecting surface 51 facing away from the first light surface 52 is connected to a side of the second reflecting surface 53 facing away from the first light surface 52; when the prism 50 is a four-prism 50, the prism 50 further includes a second light surface 54 disposed opposite to the first light surface 52, and the second light surface 54 is located between the first reflecting surface 51 and the second reflecting surface 53 and is respectively connected to the first reflecting surface 51 and the second reflecting surface 53.

In the present embodiment, the triangular prism 50 or the four-sided prism 50 is adopted to simplify the design of the optical path, so that the imaging surface 70 of the optical imaging system 100 and the lens group L10 are located on the first light surface 52 side of the four-sided prism 50, and thus, when the optical imaging system 100 is applied to an electronic device with a smaller thickness, the size of the lens group L10 is not limited by the thickness of the electronic device. When the prism 50 is a four-prism 50, the thickness of the prism 50 can be reduced more than when the prism 50 is a three-prism 50, which is more advantageous for miniaturization and light-weight of the optical imaging system 100.

It should be noted that, in the prism 50 of the embodiment of the present application, besides a triple prism or a four-prism, it may be any other prism, as long as the optical path L of the light in the prism may satisfy 0.7L/TTL 0.78 or less, and in the schematic drawing of the present application, the prism is illustrated by taking a four-prism as an example, and should not be construed as limiting the prism of the present application.

In some embodiments, the angle α between the first reflective surface 51 and the first light surface 52 ranges from: alpha is more than or equal to 27 degrees and less than or equal to 35 degrees. Specifically, the angle α between the first reflective surface 51 and the first light surface 52 may be, but is not limited to, 27 °, 28 °, 29 °, 30 °, 31 °, 32 °, 33 °, 34 °, 35 °, and the like. The angle α between the first reflecting surface 51 and the first light surface 52 is too large, which makes the optical imaging system 100 oversized, which is not beneficial to miniaturization of the optical imaging system 100, and in addition, makes the light incident to the prism 50 by the lens group L10 exceed the area of the first reflecting surface 51 of the prism 50, which affects imaging of the optical imaging system 100; the angle α between the first reflective surface 51 and the first light surface 52 is too small, so that the distance between the lens group L10 and the imaging surface 70 is too small, and when the optical imaging system 100 is applied to the camera module, the interference between the lens group L10 and the photosensitive element is easily generated.

Optionally, the range of the angle β between the second reflecting surface 53 and the first light surface 52 is: beta is more than or equal to 27 degrees and less than or equal to 35 degrees. Specifically, the angle β between the second reflective surface 53 and the first light surface 52 may be, but is not limited to, 27 °, 28 °, 29 °, 30 °, 31 °, 32 °, 33 °, 34 °, 35 °, and the like. The angle β between the second reflecting surface 53 and the first light surface 52 is too large, which is detrimental to the miniaturization of the optical imaging system 100, and the light incident to the prism 50 from the lens group L10 is easy to exceed the area of the second reflecting surface 53 of the prism 50, which affects the imaging of the optical imaging system 100; the angle β between the second reflecting surface 53 and the first light surface 52 is too small, so that the distance between the lens group L10 and the imaging surface 70 is too small, and when the optical imaging system 100 is applied to a camera module, the interference between the lens group L10 and the photosensitive element is easily generated.

In a specific embodiment, the angle α between the second reflective surface 53 and the first light surface 52 is equal to the angle β between the second reflective surface 53 and the first light surface 52. In other words, the prism 50 is an isosceles trapezoid prism 50 (i.e., a prism 50 having an isosceles trapezoid cross section) or an isosceles triangle prism 50 (i.e., a prism 50 having an isosceles triangle cross section). This can make the design of the optical path easier, and can make the imaging surface 70 of the optical imaging system 100 and the lens group L10 located on the first light surface 52 side of the four-prism 50, so that the size of the lens group L10 is not limited by the thickness of the electronic device when the optical imaging system 100 is applied to the electronic device with smaller thickness.

TTL/IMGH≤7.5；

wherein IMGH is half the diagonal length of the active pixel area on the imaging surface 70 of the optical imaging system 100.

In particular, TTL/IMGH can be, but is not limited to, 7.5, 7.3, 7.1, 7.0, 6.8, 6.6, 6.4, 6.2, 6.0, 5.8,

5.5, 5.4, 5.2, 5.0, etc. Too large a TTL/IMGH can make the optical imaging system 100 too bulky, which is detrimental to the miniaturization of the optical imaging system 100.

6.0≤TTL/IMGH≤7.5；

In this embodiment, too small TTL/IMGH reduces the focal length of the optical imaging system 100, and the super-long focus is not achieved. When the TTL/IMGH is between 6.0 and 7.5, the optical imaging system 100 can have a larger effective focal length, which is beneficial to obtaining the optical imaging system 100 with super-long focal length and is beneficial to miniaturizing the optical imaging system 100.

10°≤FOV≤30°；

wherein FOV is the maximum field angle of the optical imaging system 100.

Specifically, the maximum field angle FOV of the optical imaging system 100 may be, but is not limited to, 10 °, 12 °, 14 °, 16 °, 18 °, 20 °, 22 °, 24 °, 26 °, 28 °, 30 °, etc. The maximum field angle FOV of the optical imaging system 100 is too small, so that the imaging area of the optical imaging system 100 is small, which makes the use scene and the photographed object of the optical imaging system 100 limited, and is not beneficial to the use of the optical imaging system 100; too large a maximum field angle FOV of the optical imaging system 100 may reduce the effective focal length of the optical imaging system 100, even making the required thickness of the prism 50 impossible. When the maximum field angle FOV of the optical imaging system 100 is between 10 ° and 30 °, the optical imaging system 100 can have a more suitable imaging area and a larger effective focal length.

Further, the maximum field angle FOV of the optical imaging system 100 is in the range of 15 DEG.ltoreq.FOV.ltoreq.25°. This may allow for a more appropriately sized imaging region with a larger effective focal length.

2.2≤EFL/EPD≤4.0；

where EFL is the effective focal length of the optical imaging system 100 and EPD is the entrance pupil diameter of the optical imaging system 100.

The term "effective focal length" in this application refers to the actual focal length of optical imaging system 100, i.e., the physical length of optical imaging system 100.

Specifically, the ratio EFL/EPD of the effective focal length EFL of the optical imaging system 100 to the entrance pupil diameter EPD of the optical imaging system 100 may be, but is not limited to, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, etc. If the ratio of the effective focal length EFL of the optical imaging system 100 to the entrance pupil diameter EPD of the optical imaging system 100 is too small, the entrance pupil diameter EPD of the optical imaging system 100 may be too large, so that light cannot be gathered, the imaging image quality of the optical imaging system 100 is reduced, or the effective focal length of the optical imaging system 100 may be too small, which is not beneficial to obtaining an ultra-long focal optical imaging lens; if the ratio of the effective focal length EFL of the optical imaging system 100 to the entrance pupil diameter EPD of the optical imaging system 100 is too large, the entrance pupil diameter EPD of the optical imaging system 100 may be too small to realize a large aperture. When the ratio EFL/EPD of the effective focal length EFL of the optical imaging system 100 to the entrance pupil diameter EPD of the optical imaging system 100 is between 2.2 and 4.0, the optical imaging system 100 can be made to have a larger aperture (i.e., a large aperture), and the optical imaging system 100 can be made to have a longer focal length.

Further, the ratio EFL/EPD of the effective focal length EFL of the optical imaging system 100 to the entrance pupil diameter EPD of the optical imaging system 100 is in the range of 2.5.ltoreq.EFL/EPD.ltoreq.3.5. This may allow for both a larger aperture (i.e., a large aperture) for the optical imaging system 100 and a longer focal length for the optical imaging system 100.

Still further, the ratio EFL/EPD of the effective focal length EFL of the optical imaging system 100 to the entrance pupil diameter EPD of the optical imaging system 100 is in the range of 2.7.ltoreq.EFL/EPD.ltoreq.3.3. This may allow for both a larger aperture (i.e., a large aperture) for the optical imaging system 100 and a longer focal length for the optical imaging system 100.

0.6≤F1/EFL≤1.2；

where F1 is the effective focal length of the first lens 10 and EFL is the effective focal length of the optical imaging system 100.

Specifically, the ratio F1/EFL between the effective focal length F1 of the first lens 10 and the effective focal length EFL of the optical imaging system 100 may be, but is not limited to, 0.6, 0.62, 0.64, 0.66, 0.68, 0.7, 0.72, 0.74, 0.76, 0.78, 0.80, 0.82, 0.84, 0.85, 0.9, 0.95, 1.0, 1.05, 1.1, 1.15, 1.2, etc. If the ratio F1/EFL between the effective focal length F1 of the first lens 10 and the effective focal length EFL of the optical imaging system 100 is too small, the effective focal length of the first lens 10 is smaller, and the effective focal length of the rear lens (i.e. the second lens 20, the third lens 30 or the second lens 20, the third lens 30 and the fourth lens 40) is larger, so that the light cannot gather, and it is difficult to implement a large aperture of the optical imaging system 100; if the ratio F1/EFL between the effective focal length F1 of the first lens 10 and the effective focal length EFL of the optical imaging system 100 is too large, the first lens 10 converges light too much, which affects the effective focal length of the optical imaging system 100, and it is difficult to implement ultra-long focal length. The ratio between the effective focal length F1 of the first lens 10 and the effective focal length EFL of the optical imaging system 100 is reasonably configured, and the effective focal length of the first lens 10 is reasonably configured, so that not only can the effective deflection of the imaging light rays with a larger field of view of the optical imaging system 100 be realized, but also the focal power of the optical imaging system 100 can be prevented from being concentrated on the first lens 10, the sensitivity of the first lens 10 is reduced, and more loose tolerance conditions are provided for the actual forming and assembling process of the optical imaging system 100, namely, the requirement of the assembling tolerance of the optical imaging system 100 can be reduced, thereby reducing the assembling cost of the optical imaging system 100.

Further, the ratio F1/EFL between the effective focal length F1 of the first lens 10 and the effective focal length EFL of the optical imaging system 100 is in the range of 0.7.ltoreq.F1/EFL.ltoreq.1.1. In this way, effective deflection of imaging light rays with a larger field of view of the optical imaging system 100 can be better realized, focal power of the optical imaging system 100 can be better prevented from being concentrated on the first lens 10, sensitivity of the first lens 10 is reduced, looser tolerance conditions are provided for actual forming and assembling processes of the optical imaging system 100, and requirements of assembling tolerance of the optical imaging system 100 can be reduced, so that assembling cost of the optical imaging system 100 is reduced.

0.3≤R1/F1≤0.7；

where R1 is a radius of curvature of the first object-side surface 11 of the first lens 10, and F1 is an effective focal length of the first lens 10.

Specifically, the ratio R1/F1 of the radius of curvature of the first object-side surface 11 of the first lens 10 to the effective focal length of the first lens 10 may be, but is not limited to, 0.3, 0.33, 0.35, 0.38, 0.4, 0.43, 0.45, 0.48, 0.5, 0.53, 0.55, 0.58, 0.6, 0.63, 0.65, 0.68, 0.7, etc. When the ratio R1/F1 of the radius of curvature of the first object-side surface 11 of the first lens 10 to the effective focal length of the first lens 10 is too small, the sensitivity of the first lens 10 is increased, the requirement on the assembly tolerance of the optical imaging system 100 is increased, the optical imaging system 100 is easy to generate ghosting, and the optical imaging system 100 is easy to generate spherical aberration and chromatic aberration; when the ratio R1/F1 of the radius of curvature of the first object-side surface 11 of the first lens 10 to the effective focal length of the first lens 10 is too large, the convergence of light is insufficient, the aperture value of the optical imaging system 100 is reduced, a large aperture is difficult to realize, and spherical aberration and chromatic aberration are easily generated in the optical imaging system 100. When the ratio R1/F1 of the radius of curvature of the first object-side surface 11 of the first lens element 10 to the effective focal length of the first lens element 10 is any value between 0.3 and 0.7, the spherical aberration and chromatic aberration generated by the first lens element 10 can be reduced, and strong total reflection ghost images generated by excessively large deflection angles of light rays in the first lens element 10 can be avoided.

The term "ghosting" as used herein refers to the presence of one or more images similar to an image point in the vicinity of the image point in the optical imaging system 100, with the exception of the image point, which is collectively referred to as "ghosting".

Further, the ratio R1/F1 of the radius of curvature of the first object-side surface 11 of the first lens 10 to the effective focal length of the first lens 10 is in the range of 0.4.ltoreq.R1/F1.ltoreq.0.6. Therefore, the spherical aberration and chromatic aberration generated by the first lens 10 can be better reduced, and stronger total reflection ghost images generated by overlarge deflection angles of light rays in the first lens 10 can be better avoided.

Further, the ratio R1/F1 of the radius of curvature of the first object-side surface 11 of the first lens 10 to the effective focal length of the first lens 10 is in the range of 0.4.ltoreq.R1/F1.ltoreq.0.5. Therefore, the spherical aberration and chromatic aberration generated by the first lens 10 can be better reduced, and stronger total reflection ghost images generated by overlarge deflection angles of light rays in the first lens 10 can be better avoided.

In some embodiments, the equivalent focal length of the optical imaging system 100 ranges from 90mm to 150mm. Further, the equivalent focal length of the optical imaging system 100 ranges from 100mm to 150mm. Still further, the equivalent focal length of the optical imaging system 100 ranges from 110mm to 150mm. Still further, the equivalent focal length of the optical imaging system 100 ranges from 120mm to 145mm. In particular, the equivalent focal length of the optical imaging system 100 may be, but is not limited to, 90mm, 95mm, 100mm, 105mm, 110mm, 115mm, 120mm, 125mm, 130mm, 135mm, 140mm, 145mm, 150mm, etc. The equivalent focal length of the optical imaging system 100 is too small to obtain a long focal length optical imaging system 100.

The term "equivalent focal length" in this application refers to the size of the viewing angle obtained using the same optical imaging system 100 on different cameras or sensors. The equivalent focal length is equal to the actual focal length of the optical imaging system 100 multiplied by the clipping coefficient of the camera or sensor.

In some embodiments, the optical imaging system 100 of the embodiments further includes a diaphragm L0, where the diaphragm L0 is disposed between the object side of the first lens 10 and the second object side 21 of the second lens 20. Specifically, the stop L0 may be located on the object side of the first lens element 10, or on the first object side 11, or on the first image side 12, or between the first image side 12 and the second object side 21, or on the second image side 22.

In a specific example, the diaphragm L0 is located above the first object-side surface 11 of the first lens 10. In another specific example, between the object side of the stop L0 and the first object side 11 of the first lens 10, i.e. the stop L0 is not in direct contact with the first object side 11 of the first lens 10.

As can be understood, in the present embodiment, the optical imaging system 100 includes the first lens 10, the second lens 20, the third lens 30, the prism 50, the protection sheet 60, and the imaging surface 70 sequentially arranged from the object side to the image side along the optical axis direction; alternatively, the optical imaging system 100 includes, in the optical axis direction, the first lens 10, the second lens 20, the third lens 30, the fourth lens 40, the prism 50, the protective sheet 60, and the imaging surface 70, which are sequentially arranged from the object side to the image side.

In some embodiments, the optical imaging system 100 of the present application further includes a protection sheet 60, where the protection sheet 60 is disposed between the exit area 522 of the prism 50 and the imaging surface 70, for protecting the photosensitive element on the imaging surface 70 to achieve the dustproof effect.

Optionally, the protective sheet 60 has a fifth object side surface 61 and a fifth image side surface 62, the fifth object side surface 61 faces the exit area 522 of the first light surface 52 of the prism 50, and the fifth image side surface 62 faces the imaging surface 70.

Alternatively, the protective sheet 60 may be a glass protective sheet 60, or may be a plastic protective sheet 60.

In some embodiments, the protective sheet 60 has no blocking effect on both visible light and infrared light, in other words, both visible light and infrared light can well pass through the protective sheet 60.

In other embodiments, the protective sheet 60 is an infrared cut filter, i.e. a filter through which infrared light or infrared band is filtered and visible light can pass.

The optical imaging system 100 of the present application is further described below by way of specific embodiments.

Example 1

Referring to fig. 6, the optical imaging system 100 of the present embodiment is composed of four lenses, and the optical imaging system 100 includes, in order from an object side to an image side: a stop L0, a first lens 10 having positive power, a second lens 20 having positive power, a third lens 30 having negative power, a fourth lens 40 having negative power, a protective sheet 60, and an imaging surface 70.

In this embodiment, the first object side surface 11 and the first image side surface 12 are spherical surfaces, and the second object side surface 21, the second image side surface 22, the third object side surface 31, the third image side surface 32, the fourth object side surface 41 and the fourth image side surface 42 are aspheric surfaces.

In the present embodiment, when performance parameter testing of the optical imaging system 100 is performed, the plate glass 50a is provided between the fourth lens 40 and the protective sheet 60. When the prism 50 needs to be provided, the optical imaging system 100 of the present embodiment has an optical path L of light in the prism 50 equal to the thickness of the sheet glass 50a.

In this embodiment, BFL/TTL is 0.797; L/TTL is 0.747, TTL/IMGH is 6.936; FOV is 18.4; EFL/EPD is 3.08; F1/EFL is 0.737; R1/F1 is 0.480.

Parameters of the respective components of the optical imaging system 100 of the present embodiment are shown in table 1 below.

Table 1 parameters of various portions of optical imaging system 100

The correction coefficients of the aspherical surfaces of the respective lenses of the optical imaging system 100 of the present embodiment are shown in table 2 below.

Table 2 correction coefficients of aspherical surfaces of respective lenses of the optical imaging system 100

Fig. 7 is a spot diagram of the optical imaging system 100 of embodiment 1 of the present application. As can be seen from fig. 7, the optical imaging system 100 of the present application has a smaller light spot, and the imaging has better definition. Fig. 8 is an astigmatism and distortion graph of the optical imaging system 100 of embodiment 1 of the present application. As can be seen from fig. 8, the optical imaging system 100 of the present embodiment has less optical distortion, and thus the optical imaging system 100 of the present embodiment has better imaging quality.

Example 2

Referring to fig. 9, the lens group L10 of the optical imaging system 100 of the present embodiment is composed of four lenses, and the optical imaging system 100 includes, in order from an object side to an image side: a stop L0, a first lens 10 having positive power, a second lens 20 having positive power, a third lens 30 having negative power, a fourth lens 40 having negative power, a protective sheet 60, and an imaging surface 70.

In this embodiment, BFL/TTL is 0.796 and L/TTL is 0.733; TTL/IMGH 6.960; FOV is 18.3; EFL/EPD is 3.08; F1/EFL is 0.740; R1/F1 is 0.481.

Parameters of the respective components of the optical imaging system 100 of the present embodiment are shown in table 3 below.

Table 3 parameters of various portions of optical imaging system 100

The correction coefficients of the aspherical surfaces of the respective lenses of the optical imaging system 100 of the present embodiment are shown in table 4 below.

Table 4 correction coefficients of aspherical surfaces of respective lenses of the optical imaging system 100

Fig. 10 is a spot diagram of the optical imaging system 100 of embodiment 2 of the present application. As can be seen from fig. 10, the optical imaging system 100 of the present application has a smaller light spot, and the imaging has better definition. Fig. 11 is an astigmatism and distortion graph of the optical imaging system 100 of embodiment 2 of the present application. As can be seen from fig. 11, the optical imaging system 100 of the present embodiment has less optical distortion, and thus the optical imaging system 100 of the present embodiment has better imaging quality.

Example 3

Referring to fig. 12, the lens group L10 of the optical imaging system 100 of the present embodiment is composed of four lenses, and the optical imaging system 100 includes, in order from an object side to an image side: a stop L0, a first lens 10 having positive power, a second lens 20 having positive power, a third lens 30 having negative power, a protective sheet 60, and an imaging surface 70.

In this embodiment, the first object-side surface 11 and the first image-side surface 12 are spherical surfaces, and the second object-side surface 21, the second image-side surface 22, the third object-side surface 31 and the third image-side surface 32 are aspherical surfaces.

In this embodiment, BFL/TTL is 0.812 and L/TTL is 0.761; TTL/IMGH 7.397; FOV is 18.5; EFL/EPD is 3.09; F1/EFL is 1.017; R1/F1 is 0.454.

The parameters of the respective components of the optical imaging system 100 of the present embodiment are shown in table 5 below.

Table 5 parameters of various portions of optical imaging system 100

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The correction coefficients of the aspherical surfaces of the respective lenses of the optical imaging system 100 of the present embodiment are shown in table 6 below.

Table 6 correction coefficients of aspherical surfaces of respective lenses of the optical imaging system 100

Fig. 13 is a spot diagram of the optical imaging system 100 of embodiment 3 of the present application. As can be seen from fig. 13, the optical imaging system 100 of the present application has a smaller light spot, and the imaging has better definition. Fig. 14 is an astigmatism and distortion graph of the optical imaging system 100 of embodiment 3 of the present application. As can be seen from fig. 14, the optical imaging system 100 of the present embodiment has less optical distortion, and thus the optical imaging system 100 of the present embodiment has better imaging quality.

As can be further understood from fig. 10 and 13, when the lens group L10 of the optical imaging system 100 includes four lenses, the light spots are smaller and the imaging resolution is better than that of the optical imaging system 100 having three lenses.

Referring to fig. 15, an embodiment of the present application further provides a camera module 200, which includes: the optical imaging system 100 is accommodated in the lens barrel 210, and the optical imaging system 100 and the photosensitive element 220 in the embodiment of the present application; the photosensitive element 220 is located on the image side of the optical imaging system 100.

Alternatively, the lens barrel 210 has a hollow tubular structure, the lens barrel 210 has a light-passing hole, and the optical imaging system 100 is installed in the light-passing hole of the lens barrel 210. Alternatively, each lens and prism 50 of the optical imaging system 100 may be fixed in the lens barrel 210, or may be detachably mounted in the lens barrel 210.

Specifically, the photosensitive element 220 is disposed on the imaging surface 70 of the optical imaging system 100, and is used for converting the image projected on the imaging surface 70 of the photosensitive element 220 by the optical imaging system 100 into an electrical signal with a corresponding proportional relationship, i.e. converting the optical signal into an electrical signal. It will be appreciated that the photosensitive surface of photosensitive element 220 coincides with imaging surface 70.

In some embodiments, the lens group L10 of the optical imaging system 100 is disposed on the first light surface 52 side of the prism 50 along with the photosensitive element 220. The lens group L10 is disposed corresponding to the incident area 521 of the first light surface 52, and the photosensitive element 220 is disposed corresponding to the emitting area 522 of the first light surface 52.

The photosensitive element 220 of the present application may be a photosensitive coupling element (Charge Coupled Device, CCD) or a complementary metal oxide semiconductor element (Complementary Metal-Oxide Semiconductor Sensor, CMOS sensor).

Referring to fig. 16 to 18, the embodiment of the present application further provides an electronic device 300, which includes the camera module 200 and the processor 310, where the processor 310 is electrically connected to the photosensitive element 220 of the camera module 200, and is used for controlling the photosensitive element 220 to convert an image signal projected by the optical imaging system 100 into an electrical signal.

The electronic device 300 of the present application may include, but is not limited to, an electronic device 300 with a camera function including a mobile phone, a tablet computer, a smart bracelet, a smart watch, smart glasses, a notebook computer, a camera, an electronic book reader, and the like.

For detailed descriptions of other technical features of the camera module 200 and the optical imaging system 100, please refer to the corresponding parts of the above embodiments, and the detailed descriptions are omitted herein.

Alternatively, processor 310 includes one or more general-purpose processors, where a general-purpose processor may be any type of device capable of processing electronic instructions, including a central processing unit (Central Processing Unit, CPU), microprocessor, microcontroller, main processor, controller, ASIC, and the like. The processor 310 is configured to execute various types of digitally stored instructions, such as software or firmware programs stored in memory, that enable the computing device to provide a wide variety of services.

In some embodiments, the electronic device 300 of the present application further includes a memory 320, where the memory 320 is electrically connected to the processor 310, and the memory 320 is used to store program codes required for running by the processor 310, program codes required for controlling the camera module 200, images captured by the camera module 200, and so on.

Alternatively, the Memory 320 may include Volatile Memory (Volatile Memory), such as random access Memory (Random Access Memory, RAM); the Memory 320 may also include a Non-Volatile Memory (NVM), such as Read-Only Memory (ROM), flash Memory (FM), hard Disk (HDD), or Solid State Drive (SSD). The memory 320 may also include a combination of the types of memory 320 described above.

In some embodiments, the electronic device 300 of the present application further includes a display screen 330, where the display screen 330 is electrically connected to the processor 310, and is used to display the image of the optical imaging system 100 of the camera module 200 and the image stored in the memory 320 under the control of the processor 310.

Alternatively, the display screen 330 may be, but is not limited to, one or more of a liquid crystal display screen, a light emitting diode display screen (LED display screen), a Micro light emitting diode display screen (Micro LED display screen), a sub-millimeter light emitting diode display screen (Mini LED display screen), an organic light emitting diode display screen 330 (OLED display screen 330), and the like.

In some embodiments, the electronic device 300 further includes a middle frame 340 and a housing 350, wherein the middle frame 340 is disposed between the display screen 330 and the housing 350, and a side surface of the middle frame 340 is exposed to the display screen 330, and the housing 350 and the middle frame 340 enclose an accommodating space for accommodating components of the electronic device 300 such as the processor 310, the memory 320, and the camera module 200.

Reference herein to "an embodiment," "implementation" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the present application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those of skill in the art will explicitly and implicitly appreciate that the embodiments described herein may be combined with other embodiments.

Finally, it should be noted that the above embodiments are merely for illustrating the technical solution of the present application and not for limiting, and although the present application has been described in detail with reference to the above preferred embodiments, it should be understood by those skilled in the art that the technical solution of the present application may be modified or equivalent replaced without departing from the spirit and scope of the technical solution of the present application.

Claims

1. An optical imaging system, comprising a lens group, wherein the lens group comprises a plurality of lens groups sequentially arranged from an object side to an image side:

a second lens having optical power;

a third lens having optical power; and

0.7≤BFL/TTL≤0.9；

2. The optical imaging system of claim 1, wherein the lens group further comprises a fourth lens having optical power, the fourth lens disposed between the third lens and the imaging surface.

3. The optical imaging system of claim 1, wherein the first lens has positive optical power, the second lens has positive optical power, and the third lens has negative optical power.

4. The optical imaging system of claim 2, wherein the first lens has positive optical power, the second lens has positive optical power, the third lens has negative optical power, and the fourth lens has negative optical power.

5. The optical imaging system of any of claims 1-4, wherein the optical imaging system further satisfies the following conditional expression:

TTL/IMGH≤7.5；

wherein IMGH is half the diagonal length of the effective pixel area on the imaging surface of the optical imaging system.

6. The optical imaging system of any of claims 1-4, wherein the optical imaging system further satisfies the following conditional expression:

6.0≤TTL/IMGH≤7.5；

7. The optical imaging system of any of claims 1-4, wherein the optical imaging system further satisfies the following conditional expression:

10°≤FOV≤30°；

wherein FOV is the maximum field angle of the optical imaging system.

8. The optical imaging system of any of claims 1-4, wherein the optical imaging system further satisfies the following conditional expression:

2.2≤EFL/EPD≤4.0；

where EFL is the effective focal length of the optical imaging system and EPD is the entrance pupil diameter of the optical imaging system.

9. The optical imaging system of any of claims 1-4, wherein the optical imaging system further satisfies the following conditional expression:

0.6≤F1/EFL≤1.2；

wherein F1 is the effective focal length of the first lens, and EFL is the effective focal length of the optical imaging system.

10. The optical imaging system of any of claims 1-4, wherein the optical imaging system further satisfies the following conditional expression:

0.3≤R1/F1≤0.7；

wherein R1 is a radius of curvature of the first object-side surface of the first lens, and F1 is an effective focal length of the first lens.

11. The optical imaging system of any of claims 1-4, wherein the equivalent focal length of the optical imaging system ranges from 90mm to 150mm.

12. The optical imaging system of any of claims 1-4, further comprising a prism disposed between the lens group and the imaging surface.

13. The optical imaging system of claim 12, wherein the optical imaging system further satisfies the following conditional expression:

0.7≤L/TTL≤0.78；

where L is the optical path length of the light in the prism.

14. The optical imaging system of claim 12, wherein the prism includes a first reflecting surface, a first light surface and a second reflecting surface that are sequentially connected, the first light surface faces the lens group, the first reflecting surface and the second reflecting surface are both disposed on a side of the first light surface facing away from the lens group, and light entering the prism after exiting the lens group sequentially passes through the first light surface, is reflected by the first reflecting surface, is totally reflected by the first light surface, is reflected by the second reflecting surface, and exits from the first light surface for imaging.

15. The optical imaging system of claim 14, wherein the prism is a triangular prism or a four-prism; when the prism is a triple prism, one side of the first reflecting surface, which is away from the first light surface, is connected with one side of the second reflecting surface, which is away from the first light surface; when the prism is a four-prism, the prism further comprises a second light surface which is arranged opposite to the first light surface, and the second light surface is positioned between the first reflecting surface and the second reflecting surface and is respectively connected with the first reflecting surface and the second reflecting surface.

16. The optical imaging system of claim 14, wherein the angle α between the first reflective surface and the first light surface ranges from: alpha is more than or equal to 27 degrees and less than or equal to 35 degrees; the range of the angle beta between the second reflecting surface and the first light surface is as follows: beta is more than or equal to 27 degrees and less than or equal to 35 degrees.

17. A camera module, comprising:

a lens barrel;

the optical imaging system of any of claims 1-16, the optical imaging system housed within the barrel; and

18. An electronic device, comprising:

the camera module of claim 17; and