CN112034595A

CN112034595A - Optical system, camera module and electronic equipment

Info

Publication number: CN112034595A
Application number: CN202011005228.1A
Authority: CN
Inventors: 华露; 李明; 杨健
Original assignee: OFilm Tech Co Ltd
Current assignee: Nanchang OFilm Precision Optical Products Co Ltd; OFilm Group Co Ltd
Priority date: 2020-09-22
Filing date: 2020-09-22
Publication date: 2020-12-04

Abstract

The invention provides an optical system, a camera module and an electronic device. The optical system includes, in order from an object side to an image side along an optical axis: a prism; a first lens group with positive refractive power, the first lens group comprising a first lens; the second lens group has negative refractive power and comprises a second lens, a third lens and a fourth lens; a third lens group with positive refractive power, the third lens group comprising a fifth lens element, a sixth lens element and a seventh lens element; the distances among the first lens group, the second lens group and the third lens group are adjustable, so that the optical system is positioned at a long focal end, a middle focal end and a short focal end, and the focal lengths of the optical system at the long focal end, the middle focal end and the short focal end are different. The invention solves the technical problem that the existing lens can not meet the requirements of large-range zooming and lens miniaturization at the same time.

Description

Optical system, camera module and electronic equipment

Technical Field

The invention belongs to the technical field of optical imaging, and particularly relates to an optical system, a camera module and electronic equipment.

Background

In recent years, electronic equipment carrying a plurality of lenses appears, the effects of ultra-clear shooting, wide-angle shooting and telephoto shooting are achieved by switching different lenses for the electronic equipment, and although the lens configuration of the electronic equipment meets the shooting requirements of users in different scenes, the lens cost can be increased, the space of the electronic equipment is occupied, the electronic equipment becomes thick and heavy, and the use experience of the users is influenced. Therefore, the conventional lens cannot satisfy both the requirements of wide-range zooming and lens miniaturization.

Disclosure of Invention

An object of the present application is to provide an optical system, a camera module and an electronic device, which are used for solving the above technical problems.

The invention provides an optical system, comprising in order from an object side to an image side along an optical axis: a prism; a first lens group with positive refractive power, the first lens group comprising a first lens; the second lens group has negative refractive power and comprises a second lens, a third lens and a fourth lens; a third lens group with positive refractive power, the third lens group comprising a fifth lens element, a sixth lens element and a seventh lens element; the distances among the first lens group, the second lens group and the third lens group are adjustable, so that the optical system is positioned at a long focal end, a middle focal end and a short focal end, and the focal lengths of the optical system at the long focal end, the middle focal end and the short focal end are different. The optical system can meet the requirements of large-range zooming and miniaturization through reasonably configuring the refractive power of the first lens group, the second lens group and the third lens group and reasonably configuring the distances among the first lens group, the second lens group and the third lens group. Meanwhile, the arrangement of the prism deflects the light rays to form a folding periscopic structure, so that the transverse distance is shortened, and the space occupied by an optical system is reduced; on the other hand, sufficient length is provided to the optical system to achieve the zooming feature.

In certain embodiments, the optical system satisfies the conditional expression: and Fc/Fd is greater than 1.45, wherein Fc is the focal length of the optical system at the long focal end, and Fd is the focal length of the optical system at the short focal end. When the optical system meets the conditional expression, the ratio of the focal length of the long focal end to the focal length of the short focal end is reasonably configured, so that the optical system can obtain a higher zoom ratio, and a larger shooting magnification range is realized.

In certain embodiments, the optical system satisfies the conditional expression: 4deg/mm < FOVc/ImgH <5.5deg/mm, wherein FOVc is the maximum field angle of the optical system at the long focal end, and ImgH is half of the diagonal length of the effective imaging area of the imaging surface. When the optical system meets the conditional expression, the ratio of the full field angle of the telephoto end to the half-image height is configured to be within a reasonable range, so that the telephoto characteristic of the zoom lens can be realized, and meanwhile, a chip with higher pixels can be matched, and high-definition shooting is realized.

In certain embodiments, the optical system satisfies the conditional expression: 40< TTL/(ATg2-ATg3) <95, where TTL is the distance between the object-side surface of the first lens element and the image plane of the optical system on the optical axis, ATg2 is the total of the air spaces between the adjacent lens elements of the second lens element on the optical axis, and ATg3 is the total of the air spaces between the adjacent lens elements of the third lens element on the optical axis. When the optical system meets the conditional expression, the total length of the optical system can be effectively shortened on the basis of realizing a larger zoom ratio by controlling the total sum of the air intervals on the optical axis between the adjacent lenses of the second lens group and the total sum of the air intervals on the optical axis between the adjacent lenses of the third lens group, and the space is saved for electronic equipment carrying the zoom lens.

In certain embodiments, the optical system satisfies the conditional expression: 2< (R3+ R4)/(R7+ R8) <8.5, wherein R3 is the radius of curvature of the object-side surface of the second lens at the optical axis, R4 is the radius of curvature of the image-side surface of the second lens at the optical axis, R7 is the radius of curvature of the object-side surface of the fourth lens at the optical axis, and R8 is the radius of curvature of the image-side surface of the fourth lens at the optical axis. When the optical system meets the conditional expression, the curvature radiuses of the object side and the image side surface of the first lens and the last lens of the second lens group at the optical axis are controlled within a reasonable range, so that the aberration generated by the second lens group is favorably controlled, the aberration components of the second lens group and the aberration components of the front lens group and the rear lens group are balanced, and the imaging quality of the optical system is improved; in addition, the surface shapes of the second lens and the fourth lens are favorably and reasonably restrained, and the forming processing difficulty is reduced.

In certain embodiments, the optical system satisfies the conditional expression: F2/F234<7.5, F2 is the focal length of the second lens, and F234 is the focal length of the second lens group. When the optical system meets the above conditional expression, the negative refractive power of the second lens is a part of the overall negative refractive power of the second lens group, so that the second lens group is favorable for balancing the spherical aberration generated by the front lens group by controlling the negative refractive power borne by the second lens within a reasonable range, the reasonably controllable negative refractive power is provided for the zoom lens, the imaging quality is further improved, and in addition, the total length of the system is also favorable for being shortened.

In certain embodiments, the optical system satisfies the conditional expression: 4< F1/F567<13, wherein F1 is a focal length of the first lens group, and F567 is a focal length of the third lens group. When the optical system meets the conditional expression, the ratio of the focal length of the first lens group to the focal length of the third lens group is reasonably configured, so that a wider zooming range is favorably obtained, in addition, the positive refractive power borne by the third lens of the first lens combination is reasonably controlled, the negative refractive power contributed by the second lens group is matched, the positions of the lens groups are moved under the action of the cam, different focal lengths in three zooming states are jointly realized, and the required zooming characteristic is achieved.

In certain embodiments, the optical system satisfies the conditional expression: 1.9< F1/Fc <6, where F1 is the focal length of the first lens group and Fc is the focal length of the optical system at the telephoto end. When the optical system meets the conditional expression, the ratio of the focal length of the first lens group to the focal length of the telephoto end is reasonably configured, which is beneficial to obtaining a wider zoom range in the telephoto direction, and meanwhile, the first lens group is distributed with proper refractive power to be beneficial to correcting distortion and spherical aberration, so that the resolution power of the system is further improved.

In certain embodiments, the optical system satisfies the conditional expression: g3/(g1+ g2) <2, wherein g1 is the distance on the optical axis from the object-side surface of the first lens to the image-side surface of the first lens, g2 is the distance on the optical axis from the object-side surface of the second lens to the image-side surface of the fourth lens, and g3 is the distance on the optical axis from the object-side surface of the fifth lens to the image-side surface of the seventh lens. When the optical system meets the conditional expression, the total length of the optical system is favorably shortened by reasonably configuring the total thickness of the three lens groups, the thickness and the distance of the lenses of each lens group are controlled in a reasonable range, on one hand, materials are saved, and on the other hand, good processability can be ensured.

In certain embodiments, the optical system satisfies the conditional expression: 2< R14/F7<12, wherein R14 is a radius of curvature of the image side surface of the seventh lens at the optical axis, and F7 is a focal length of the seventh lens. When the optical system meets the conditional expression, the ratio of the curvature radius of the image side surface of the seventh lens at the optical axis to the effective focal length of the seventh lens is controlled, so that the seventh lens surface type is easy to process, and the aberration generated by the front lens group is balanced.

The invention provides a camera module, which comprises a lens barrel, an electronic photosensitive element and the optical system, wherein the first lens to the seventh lens of the optical system are arranged in the lens barrel, and the electronic photosensitive element is arranged at the image side of the optical system and is used for converting light rays of objects which pass through the first lens to the seventh lens and are incident on the electronic photosensitive element into electric signals of images. This application is through installing this optical system's first lens to seventh lens in the module of making a video recording, and the face type and the power of refracting of each lens of rational configuration first lens to seventh lens can make the module of making a video recording satisfy simultaneously on a large scale zoom with miniaturized requirement.

The invention provides electronic equipment which comprises a shell and the camera module, wherein the camera module is arranged in the shell. This application can be so that electronic equipment satisfies the requirement of zooming on a large scale and miniaturization simultaneously through set up above-mentioned module of making a video recording in electronic equipment.

To sum up, this application can change the prism part of light path trend through the setting to can transversely arrange the camera lens in the electronic equipment shell during the installation, can reduce the horizontal length and the whole height of camera lens, satisfy pixel quantity increase gradually, zoom scope enlarges gradually and the miniaturized requirement of optics getting for instance camera lens, and then realize electronic equipment's frivolousization requirement.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1a is a schematic diagram of the optical system of the first embodiment at the short focal end;

FIG. 1b is a longitudinal spherical aberration curve, an astigmatism curve and a distortion curve of the optical system of the first embodiment at the short focal end;

FIG. 1c is a schematic diagram of the optical system of the first embodiment at the mid-focal end;

FIG. 1d is a longitudinal spherical aberration curve, an astigmatism curve, and a distortion curve of the optical system of the first embodiment at the mid-focal end;

FIG. 1e is a schematic diagram of the optical system of the first embodiment at the tele end;

FIG. 1f is a longitudinal spherical aberration curve, an astigmatism curve, and a distortion curve of the optical system of the first embodiment at the tele end;

FIG. 2a is a schematic diagram of the optical system of the second embodiment at the short focal end;

FIG. 2b is a longitudinal spherical aberration curve, an astigmatism curve and a distortion curve of the optical system of the second embodiment at the short focal end;

FIG. 2c is a schematic diagram of the optical system of the second embodiment at the mid-focal end;

FIG. 2d is a longitudinal spherical aberration curve, an astigmatism curve and a distortion curve of the optical system of the second embodiment at the middle focal end;

FIG. 2e is a schematic diagram of the optical system of the second embodiment at the tele end;

FIG. 2f is a longitudinal spherical aberration curve, an astigmatism curve, and a distortion curve of the optical system of the second embodiment at the tele end;

FIG. 3a is a schematic diagram of the optical system of the third embodiment at the short focal end;

FIG. 3b is a longitudinal spherical aberration curve, an astigmatism curve and a distortion curve of the optical system of the third embodiment at the short focal end;

FIG. 3c is a schematic diagram of the optical system of the third embodiment at the mid-focal end;

FIG. 3d is a longitudinal spherical aberration curve, an astigmatism curve and a distortion curve of the optical system of the third embodiment at the middle focal end;

FIG. 3e is a schematic diagram of the optical system of the third embodiment at the tele end;

FIG. 3f is a longitudinal spherical aberration curve, an astigmatism curve, and a distortion curve of the optical system of the third embodiment at the tele end;

FIG. 4a is a schematic diagram of the optical system of the fourth embodiment at the short focal end;

FIG. 4b is a longitudinal spherical aberration curve, an astigmatism curve and a distortion curve of the optical system of the fourth embodiment at the short focal end;

FIG. 4c is a schematic diagram of the optical system of the fourth embodiment at the mid-focal end;

FIG. 4d is a longitudinal spherical aberration curve, an astigmatism curve and a distortion curve of the optical system of the fourth embodiment at the middle focal end;

FIG. 4e is a schematic diagram of the optical system of the fourth embodiment at the tele end;

FIG. 4f is a longitudinal spherical aberration curve, an astigmatism curve, and a distortion curve of the optical system of the fourth embodiment at the tele end;

FIG. 5a is a schematic diagram of the optical system of the fifth embodiment at the short focal end;

FIG. 5b is a longitudinal spherical aberration curve, an astigmatism curve and a distortion curve of the optical system of the fifth embodiment at the short focal end;

FIG. 5c is a schematic diagram of the optical system of the fifth embodiment at the mid-focal end;

FIG. 5d is a longitudinal spherical aberration curve, an astigmatism curve and a distortion curve of the optical system of the fifth embodiment at the middle focal end;

FIG. 5e is a schematic diagram of the optical system of the fifth embodiment at the tele end;

FIG. 5f is a longitudinal spherical aberration curve, an astigmatism curve, and a distortion curve of the optical system of the fifth embodiment at the tele end;

FIG. 6a is a schematic diagram of the optical system of the sixth embodiment at the short focal end;

FIG. 6b is a longitudinal spherical aberration curve, an astigmatism curve and a distortion curve of the optical system of the sixth embodiment at the short focal end;

FIG. 6c is a schematic diagram of the optical system of the sixth embodiment at the mid-focal end;

FIG. 6d is a longitudinal spherical aberration curve, an astigmatism curve and a distortion curve of the optical system of the sixth embodiment at the middle focal end;

FIG. 6e is a schematic diagram of the optical system of the sixth embodiment at the tele end;

fig. 6f is a longitudinal spherical aberration curve, an astigmatism curve, and a distortion curve of the optical system of the sixth embodiment at the telephoto end.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The embodiment of the application provides a camera module, which comprises a lens barrel, an electronic photosensitive element and an optical system, wherein a first lens, a second lens, a third lens and a fourth lens of the optical system are arranged in the lens barrel, and the electronic photosensitive element is arranged on the image side of the optical system and is used for converting light rays of objects which pass through the first lens, the second lens, the third lens and the fourth lens and are incident on the electronic photosensitive element into electric signals of images. The electron sensor may be a Complementary Metal Oxide Semiconductor (CMOS) or a Charge-coupled Device (CCD). The camera module can be an independent lens of a digital camera and also can be an imaging module integrated on electronic equipment such as a smart phone. This application is through installing this optical system's first lens to seventh lens in the module of making a video recording, and the face type and the power of refracting of each lens of rational configuration first lens to seventh lens can make the module of making a video recording satisfy simultaneously on a large scale zoom with miniaturized requirement.

The embodiment of the application provides an electronic equipment, and the electronic equipment comprises a shell and a camera module provided by the embodiment of the application. The camera module and the electronic photosensitive element are arranged in the shell. The electronic device can be a smart phone, a Personal Digital Assistant (PDA), a tablet computer, a smart watch, an unmanned aerial vehicle, an electronic book reader, a vehicle event data recorder, a wearable device and the like. This application can be so that electronic equipment satisfies the requirement of zooming on a large scale and miniaturization simultaneously through set up the module of making a video recording in electronic equipment.

The present disclosure provides an optical system, sequentially from an object side to an image side along an optical axis direction, comprising: a prism; a first lens group with positive refractive power, the first lens group comprising a first lens; the second lens group has negative refractive power and comprises a second lens, a third lens and a fourth lens; and the third lens group has positive refractive power and comprises a fifth lens, a sixth lens and a seventh lens. In the first to seventh lenses, any two adjacent lenses may have an air space therebetween.

The distances among the first lens group, the second lens group and the third lens group are adjustable, so that the optical system is positioned at a long focal end, a middle focal end and a short focal end, and the focal lengths of the optical system at the long focal end, the middle focal end and the short focal end are different.

The optical system can meet the requirements of large-range zooming and miniaturization through reasonably configuring the refractive power of the first lens group, the second lens group and the third lens group and reasonably configuring the distances among the first lens group, the second lens group and the third lens group. Meanwhile, the arrangement of the prism deflects the light rays to form a folding periscopic structure, so that the transverse distance is shortened, and the space occupied by an optical system is reduced; on the other hand, sufficient length is provided to the optical system to achieve the zooming feature.

It is understood that when zooming is performed from the short focal end to the long focal end position, the prism, the first lens group and the image plane remain stationary, the distance between the first lens group and the second lens group increases, the distance between the third lens group and the image plane also increases, and the optical system includes at least one aspherical plastic lens.

In a specific embodiment, the optical system satisfies the conditional expression: and Fc/Fd is greater than 1.45, wherein Fc is the focal length of the optical system at the long focal end, and Fd is the focal length of the optical system at the short focal end. When the optical system meets the conditional expression, the ratio of the focal length of the long focal end to the focal length of the short focal end is reasonably configured, so that the optical system can obtain a higher zoom ratio, and a larger shooting magnification range is realized. When Fc/Fd is less than or equal to 1.45, the higher requirement of the user on the shooting experience is not satisfied.

In a specific embodiment, the optical system satisfies the conditional expression: 4deg/mm < FOVc/ImgH <5.5deg/mm, wherein FOVc is the maximum field angle of the optical system at the long focal end, and ImgH is half of the diagonal length of the effective imaging area of the imaging surface. When the optical system meets the conditional expression, the ratio of the maximum field angle of the telephoto end to the half-image height is configured to be within a reasonable range, so that the telephoto characteristic of the zoom lens can be realized, and meanwhile, a chip with higher pixels can be matched, and high-definition shooting is realized.

In a specific embodiment, the optical system satisfies the conditional expression: 40< TTL/(ATg2-ATg3) <95, where TTL is the distance between the object-side surface of the first lens element and the image plane of the optical system on the optical axis, ATg2 is the total of the air spaces between the adjacent lens elements of the second lens element on the optical axis, and ATg3 is the total of the air spaces between the adjacent lens elements of the third lens element on the optical axis. When the optical system meets the conditional expression, the total length of the optical system can be effectively shortened on the basis of realizing a larger zoom ratio by controlling the total sum of the air intervals on the optical axis between the adjacent lenses of the second lens group and the total sum of the air intervals on the optical axis between the adjacent lenses of the third lens group, and the space is saved for electronic equipment carrying the zoom lens.

In a specific embodiment, TTL is ≦ 34 mm. When the optical system meets the conditional expression, the length of the optical system is appropriate, pressure cannot be increased for space configuration of the electronic equipment, other parts cannot be extruded, and the stability of the optical system is good. When TTL is greater than 34mm, the total length of the optical system is too large, which may increase pressure on the space configuration of the electronic device, and may cause the optical system to have poor stability due to being squeezed to other parts.

In a specific embodiment, the optical system satisfies the conditional expression: 2< (R3+ R4)/(R7+ R8) <8.5, wherein R3 is the radius of curvature of the object-side surface of the second lens at the optical axis, R4 is the radius of curvature of the image-side surface of the second lens at the optical axis, R7 is the radius of curvature of the object-side surface of the fourth lens at the optical axis, and R8 is the radius of curvature of the image-side surface of the fourth lens at the optical axis. It is understood that the second lens and the fourth lens are the first lens and the last lens of the second lens group, respectively. When the optical system meets the conditional expression, the curvature radiuses of the object side and the image side surface of the first lens and the last lens of the second lens group at the optical axis are controlled within a reasonable range, so that the aberration generated by the second lens group is favorably controlled, the aberration components of the second lens group and the aberration components of the front lens group and the rear lens group are balanced, and the imaging quality of the optical system is improved; in addition, the surface shapes of the second lens and the fourth lens are favorably and reasonably restrained, and the forming processing difficulty is reduced.

In a specific embodiment, the optical system satisfies the conditional expression: F2/F234<7.5, F2 is the focal length of the second lens, and F234 is the focal length of the second lens group. When the optical system meets the above conditional expression, the negative refractive power of the second lens is a part of the overall negative refractive power of the second lens group, so that the second lens group is favorable for balancing the spherical aberration generated by the front lens group by controlling the negative refractive power borne by the second lens within a reasonable range, the reasonably controllable negative refractive power is provided for the zoom lens, the imaging quality is further improved, and in addition, the total length of the system is also favorable for being shortened. When F2/F234 is greater than or equal to 7.5, the negative refractive power borne by the second lens element is too small, which directly results in the reduction of the negative refractive power of the second lens element and is not favorable for correcting the aberration generated by the front and rear lens elements.

In a specific embodiment, the optical system satisfies the conditional expression: 4< F1/F567<13, wherein F1 is a focal length of the first lens group, and F567 is a focal length of the third lens group. When the optical system meets the conditional expression, the ratio of the focal length of the first lens group to the focal length of the third lens group is reasonably configured, so that a wider zooming range is favorably obtained, in addition, the positive refractive power borne by the third lens of the first lens combination is reasonably controlled, the negative refractive power contributed by the second lens group is matched, the positions of the lens groups are moved under the action of the cam, different focal lengths in three zooming states are jointly realized, and the required zooming characteristic is achieved.

In a specific embodiment, the optical system satisfies the conditional expression: 1.9< F1/Fc <6, where F1 is the focal length of the first lens group and Fc is the focal length of the optical system at the telephoto end. When the optical system meets the conditional expression, the ratio of the focal length of the first lens group to the focal length of the telephoto end is reasonably configured, which is beneficial to obtaining a wider zoom range in the telephoto direction, and meanwhile, the first lens group is distributed with proper refractive power to be beneficial to correcting distortion and spherical aberration, so that the resolution power of the system is further improved. When F1/Fc is more than or equal to 6, the focal length at the telephoto end is too small to realize the telephoto characteristic, and the zoom ratio is also reduced, which finally results in reduced market competitiveness.

In a specific embodiment, the optical system satisfies the conditional expression: g3/(g1+ g2) <2, wherein g1 is the distance on the optical axis from the object-side surface of the first lens to the image-side surface of the first lens, g2 is the distance on the optical axis from the object-side surface of the second lens to the image-side surface of the fourth lens, and g3 is the distance on the optical axis from the object-side surface of the fifth lens to the image-side surface of the seventh lens. When the optical system meets the conditional expression, the total length of the optical system is favorably shortened by reasonably configuring the total thickness of the three lens groups, the thickness and the distance of the lenses of each lens group are controlled in a reasonable range, on one hand, materials are saved, and on the other hand, good processability can be ensured. When g3/(g1+ g2) ≥ 2, the thickness and air interval distribution of each lens group lens of the optical system are easily caused to be uneven, and the assembly difficulty is increased.

In a specific embodiment, the optical system satisfies the conditional expression: 2< R14/F7<12, wherein R14 is a radius of curvature of the image side surface of the seventh lens at the optical axis, and F7 is a focal length of the seventh lens. When the optical system meets the conditional expression, the ratio of the curvature radius of the image side surface of the seventh lens at the optical axis to the effective focal length of the seventh lens is controlled, so that the seventh lens surface type is easy to process, and the aberration generated by the front lens group is balanced. When R14/F7 is less than or equal to 2, the positive refractive power borne by the seventh lens element is too large, which tends to cause too large deflection of the external field rays, and further causes the reasonable transition to the image plane, and finally causes the overall imaging quality to be reduced. When R14/F7 is larger than or equal to 12, the image side surface of the seventh lens is too gentle, the capability of deflecting light rays is weakened, the capability of balancing and correcting aberration is weakened, and the good imaging quality is not ensured.

In a first embodiment of the present invention, the first,

referring to fig. 1a to fig. 1f, the optical system of the present embodiment, in order from an object side to an image side along an optical axis direction, includes:

the prism E has an incident surface a1, a reflecting surface a2, and an exit surface A3. It is understood that when light from a subject enters the prism E via the incident surface a1, it can be totally reflected by the reflecting surface a2 toward the exit surface A3 to exit in the direction of the optical axis.

The first lens element L1 with positive refractive power has an object-side surface S1 of the first lens element L1 being convex at paraxial region and an image-side surface S2 being concave at paraxial region; the object-side surface S1 of the first lens element L1 is convex at the circumference, and the image-side surface S2 is concave at the circumference.

A second lens element L2 with negative refractive power having an object-side surface S3 of the second lens element L2 being convex at paraxial region and an image-side surface S4 being concave at paraxial region; the object-side surface S3 of the second lens element L2 is convex at the circumference, and the image-side surface S4 is concave at the circumference.

The third lens element L3 with positive refractive power has an object-side surface S5 of the third lens element L3 being concave at a paraxial region and an image-side surface S6 being convex at a paraxial region; the object-side surface S5 of the third lens element L3 is convex at the circumference, and the image-side surface S6 is convex at the circumference.

A fourth lens element L4 with negative refractive power having a concave object-side surface S7 at paraxial region and a concave image-side surface S8 at paraxial region; the object-side surface S7 of the fourth lens element L4 is concave at the circumference, and the image-side surface S8 is convex at the circumference.

The fifth lens element L5 with positive refractive power has an object-side surface S9 of the fifth lens element L5 being convex at paraxial region and an image-side surface S10 being convex at paraxial region; the object-side surface S9 of the fifth lens element L5 is convex at the circumference, and the image-side surface S10 is concave at the circumference.

The sixth lens element L6 with negative refractive power has a concave object-side surface S11 at paraxial region and a concave image-side surface S12 at paraxial region; the object-side surface S11 of the sixth lens element L6 is convex and the image-side surface S12 is concave.

The seventh lens element L7 with positive refractive power has an object-side surface S13 of the seventh lens element L7 being convex at paraxial region and an image-side surface S14 being concave at paraxial region; the object-side surface S13 of the seventh lens element L7 is concave at the circumference, and the image-side surface S14 is convex at the circumference.

The first lens L1 to the seventh lens L7 are made of plastic or glass. At least one of the first lens L1 to the seventh lens L7 is made of plastic.

Further, the optical system includes a stop STO, an infrared filter L8, and an image plane S17. A stop STO is provided between the fourth lens L4 and the fifth lens L5 for controlling the amount of incoming light. In other embodiments, the stop STO can be disposed between two adjacent lenses or on other lenses. The infrared filter L8 is disposed on the image side of the seventh lens L7, and includes an object side surface S15 and an image side surface S16, and the infrared filter L8 is configured to filter infrared light, so that the light incident on the image surface S17 is visible light, and the wavelength of the visible light is 380nm-780 nm. The infrared filter L8 is made of glass, and may be coated with a film. The image plane S17 is a plane on which an image formed by the light of the subject passing through the optical system is located. The prism E may be a right-angle prism.

Tables 1a (1) -1 a (2) show tables of characteristics of the optical system of the present embodiment, and units of the Y radius, thickness, and focal length are all millimeters (mm).

TABLE 1a (1)

TABLE 1a (2)

Variable distance	D1	D2	D3	f(mm)	FNO	FOV(°)
							Short focal length position	-0.3441	-5.3239	-7.2270	15.4	3.27	29.5
Position of middle focus	-1.2762	-3.1307	-8.4798	18.6	3.86	24.3
							Position of long focus	-1.4479	-0.4121	-11.0350	24.3	5.04	18.6

Wherein f is a focal length of the optical system, FNO is an f-number of the optical system, FOV is a field angle of the optical system, and TTL is a distance on an optical axis from an object-side surface of the first lens to an image plane of the optical system. The positive and negative of the thickness value represent directions only.

In the present embodiment, the object-side surface and the image-side surface of any one of the third lens L3 to the seventh lens L7 are aspheric surfaces, and the surface shape x of each aspheric lens can be defined by, but is not limited to, the following aspheric surface formula:

wherein x is the rise of the distance from the aspheric surface vertex to the aspheric surface vertex when the aspheric surface is at the position with the height of h along the optical axis direction; c is the paraxial curvature of the aspheric surface, c being 1/R (i.e., paraxial curvature c is the reciprocal of the radius R of Y in table 1a (1) above); k is a conic coefficient; ai is the correction coefficient of the i-th order of the aspherical surface. Table 1b shows the high-order coefficient A4, A6, A8, A10, A12, A14, A16, A18 and A20 of each of the aspherical mirrors S1-S14 usable in the first embodiment.

TABLE 1b

Fig. 1a shows a schematic configuration of the optical system of the first embodiment at the short focal end. Fig. 1b shows a longitudinal spherical aberration curve, an astigmatism curve, and a distortion curve of the optical system of the first embodiment at the short focal end. The longitudinal spherical aberration curve represents the deviation of the convergence focus of the light rays with different wavelengths after passing through each lens of the optical system; the astigmatism curves represent meridional image surface curvature and sagittal image surface curvature; the distortion curve represents the distortion magnitude values corresponding to different angles of view. As can be seen from fig. 1b, the optical system according to the first embodiment can achieve good imaging quality.

Fig. 1c shows a schematic configuration of the optical system of the first embodiment at the mid-focal end. Fig. 1d shows the longitudinal spherical aberration curve, astigmatism curve and distortion curve of the optical system of the first embodiment at the mid-focal end. The longitudinal spherical aberration curve represents the deviation of the convergence focus of the light rays with different wavelengths after passing through each lens of the optical system; the astigmatism curves represent meridional image surface curvature and sagittal image surface curvature; the distortion curve represents the distortion magnitude values corresponding to different angles of view. As can be seen from fig. 1d, the optical system according to the first embodiment can achieve good imaging quality.

Fig. 1e shows a schematic configuration of the optical system of the first embodiment at the tele end. Fig. 1f shows the longitudinal spherical aberration curve, astigmatism curve and distortion curve of the optical system of the first embodiment at the tele end. The longitudinal spherical aberration curve represents the deviation of the convergence focus of the light rays with different wavelengths after passing through each lens of the optical system; the astigmatism curves represent meridional image surface curvature and sagittal image surface curvature; the distortion curve represents the distortion magnitude values corresponding to different angles of view. As can be seen from fig. 1f, the optical system according to the first embodiment can achieve good imaging quality.

In a second embodiment of the present invention, the first embodiment,

referring to fig. 2 a-2 f, the optical system of the present embodiment, in order from an object side to an image side along an optical axis direction, includes:

The third lens element L3 with positive refractive power has an object-side surface S5 of the third lens element L3 being concave at a paraxial region and an image-side surface S6 being convex at a paraxial region; the object-side surface S5 of the third lens element L3 is convex at the circumference, and the image-side surface S6 is concave at the circumference.

A fourth lens element L4 with negative refractive power having a concave object-side surface S7 and a concave image-side surface S8 at paraxial region, respectively, of the fourth lens element L4; the object-side surface S7 of the fourth lens element L4 is concave at the circumference, and the image-side surface S8 is convex at the circumference.

Other structures of the second embodiment are the same as those of the first embodiment, and reference may be made thereto.

Tables 2a (1) -2 a (2) show tables of characteristics of the optical system of the present embodiment, and units of the Y radius, thickness, and focal length are all millimeters (mm).

TABLE 2a (1)

TABLE 2a (2)

Variable distance	D1	D2	D3	f(mm)	FNO	FOV(°)
							Short focal length position	-0.0500	-5.6105	-9.1817	16	3.79	28.3
Position of middle focus	-1.1000	-3.2195	-10.5077	19.2	4.15	23.5
							Position of long focus	-1.4491	-0.0500	-13.3481	25.5	5	17.7

Wherein, the meanings of the parameters in tables 2a (1) to 2a (2) are the same as those of the first embodiment.

Table 2b gives the coefficients of high order terms that can be used for each aspherical mirror in the second embodiment, wherein each aspherical mirror type can be defined by the formula given in the first embodiment.

TABLE 2b

Fig. 2a shows a schematic structural view of the optical system of the second embodiment at the short focal end. Fig. 2b shows the longitudinal spherical aberration curve, astigmatism curve and distortion curve of the optical system of the second embodiment at the short focal end. As can be seen from fig. 2b, the optical system according to the second embodiment can achieve good imaging quality.

Fig. 2c shows a schematic configuration of the optical system of the second embodiment at the mid-focal end. Fig. 2d shows the longitudinal spherical aberration curve, astigmatism curve and distortion curve of the optical system of the second embodiment at the mid-focal end. As can be seen from fig. 2d, the optical system according to the second embodiment can achieve good imaging quality.

Fig. 2e shows a schematic configuration of the optical system of the second embodiment at the tele end. Fig. 2f shows the longitudinal spherical aberration curve, astigmatism curve and distortion curve of the optical system of the second embodiment at the tele end. As can be seen from fig. 2f, the optical system according to the second embodiment can achieve good imaging quality.

In a third embodiment of the present invention, the first,

referring to fig. 3a to fig. 3f, the optical system of the present embodiment, in order from an object side to an image side along an optical axis direction, includes:

The first lens element L1 with positive refractive power has an object-side surface S1 of the first lens element L1 being convex at a paraxial region and an image-side surface S2 being convex at a paraxial region; the object-side surface S1 of the first lens element L1 is convex at the circumference, and the image-side surface S2 is convex at the circumference.

The third lens element L3 with positive refractive power has an object-side surface S1 of the third lens element L3 being concave at a paraxial region and an image-side surface S2 being convex at a paraxial region; the object-side surface S5 of the third lens element L3 is convex at the circumference, and the image-side surface S6 is concave at the circumference.

Other structures of the third embodiment are the same as those of the first embodiment, and reference may be made thereto.

Tables 3a (1) -3 a (2) show tables of characteristics of the optical system of the present embodiment, and units of the Y radius, thickness, and focal length are all millimeters (mm).

TABLE 3a (1)

TABLE 3a (2)

Variable distance	D1	D2	D3	f(mm)	FNO	FOV(°)
							Short focal length position	-0.0997	-5.3805	-7.5445	-14.4	3.11	31.5
Position of middle focus	-1.2100	-2.7548	-9.0445	-17.9	3.68	25.3
							Position of long focus	-1.4478	-0.2136	-11.3633	-22.8	4.83	19.8

Wherein, the meanings of the parameters in tables 3a (1) to 3a (2) are the same as those of the first embodiment.

Table 3b gives the coefficients of high-order terms that can be used for each aspherical mirror surface in the third embodiment, wherein each aspherical mirror surface type can be defined by the formula given in the first embodiment.

TABLE 3b

Fig. 3a shows a schematic structure diagram of the optical system of the third embodiment at the short focal end. Fig. 3b shows the longitudinal spherical aberration curve, astigmatism curve and distortion curve of the optical system of the third embodiment at the short focal end. As can be seen from fig. 3b, the optical system according to the third embodiment can achieve good imaging quality.

Fig. 3c shows a schematic configuration of the optical system of the third embodiment at the mid-focal end. Fig. 3d shows the longitudinal spherical aberration curve, astigmatism curve and distortion curve of the optical system of the third embodiment at the mid-focal end. As can be seen from fig. 3d, the optical system according to the third embodiment can achieve good imaging quality.

Fig. 3e shows a schematic configuration of the optical system of the third embodiment at the tele end. Fig. 3f shows the longitudinal spherical aberration curve, astigmatism curve and distortion curve of the optical system of the third embodiment at the tele end. As can be seen from fig. 3f, the optical system according to the third embodiment can achieve good imaging quality.

In a fourth embodiment of the present invention,

referring to fig. 4a to fig. 4f, the optical system of the present embodiment, in order from an object side to an image side along an optical axis direction, includes:

The first lens element L1 with positive refractive power has an object-side surface S1 of the first lens element L1 being concave at a paraxial region and an image-side surface S2 being convex at a paraxial region; the object-side surface S1 of the first lens element L1 is concave at the circumference, and the image-side surface S2 is convex at the circumference.

Other structures of the fourth embodiment are the same as those of the first embodiment, and reference may be made thereto.

Tables 4a (1) -4 a (2) show tables of characteristics of the optical system of the present embodiment, and units of the Y radius, thickness, and focal length are all millimeters (mm).

TABLE 4a (1)

TABLE 4a (2)

Variable distance	D1	D2	D3	f(mm)	FNO	FOV(°)
							Short focal length position	-0.0500	-5.2665	-7.2839	13.2	3.37	34.3
Position of middle focus	-1.2100	-2.5568	-8.8186	16.5	3.73	27.3
							Position of long focus	-1.4478	-0.0500	-11.1027	21.2	4.52	21.2

The values of the parameters in tables 4a (1) to 4a (2) are the same as those in the first embodiment.

Table 4b gives the coefficients of high-order terms that can be used for each aspherical mirror surface in the fourth embodiment, wherein each aspherical mirror surface type can be defined by the formula given in the first embodiment.

TABLE 4b

Fig. 4a shows a schematic structural view of the optical system of the fourth embodiment at the short focal end. Fig. 4b shows a longitudinal spherical aberration curve, an astigmatism curve and a distortion curve of the optical system of the fourth embodiment at the short focal end. As can be seen from fig. 4b, the optical system according to the fourth embodiment can achieve good imaging quality.

Fig. 4c shows a schematic structural view of the optical system of the fourth embodiment at the mid-focal end. Fig. 4d shows the longitudinal spherical aberration curve, astigmatism curve and distortion curve of the optical system of the fourth embodiment at the mid-focal end. As can be seen from fig. 4d, the optical system according to the fourth embodiment can achieve good imaging quality.

Fig. 4e shows a schematic configuration of the optical system of the fourth embodiment at the tele end. Fig. 4f shows the longitudinal spherical aberration curve, astigmatism curve and distortion curve of the optical system of the fourth embodiment at the tele end. As can be seen from fig. 4f, the optical system according to the fourth embodiment can achieve good imaging quality.

In the fifth embodiment, the first embodiment,

referring to fig. 5a to 5f, the optical system of the present embodiment, in order from an object side to an image side along an optical axis direction, includes:

The other structure of the fifth embodiment is the same as that of the first embodiment, and reference may be made thereto.

Tables 5a (1) -5 a (2) show tables of characteristics of the optical system of the present embodiment, and units of the Y radius, thickness, and focal length are all millimeters (mm).

TABLE 5a (1)

TABLE 5a (2)

Variable distance	D1	D2	D3	f(mm)	FNO	FOV(°)
							Short focal length position	-0.1055	-5.4875	-7.8443	14.6	3.29	31.1
Position of middle focus	-1.2100	-2.8630	-9.3443	18.1	3.61	25
							Position of long focus	-1.4478	-0.3264	-11.6631	23.1	4.45	19.6

Wherein, the meanings of the parameters in tables 5a (1) to 5a (2) are the same as those of the first embodiment.

Table 5b shows the high-order term coefficients that can be used for each aspherical mirror surface in the fifth embodiment, wherein each aspherical mirror surface type can be defined by the formula given in the first embodiment.

TABLE 5b

Fig. 5a shows a schematic structural view of the optical system of the fifth embodiment at the short focal end. Fig. 5b shows a longitudinal spherical aberration curve, an astigmatism curve, and a distortion curve of the optical system of the fifth embodiment at the short focal end. As can be seen from fig. 5b, the optical system according to the fifth embodiment can achieve good image quality.

Fig. 5c shows a schematic configuration of the optical system of the fifth embodiment at the mid-focal end. Fig. 5d shows the longitudinal spherical aberration curve, astigmatism curve and distortion curve of the optical system of the fifth embodiment at the mid-focal end. As can be seen from fig. 5d, the optical system according to the fifth embodiment can achieve good image quality.

Fig. 5e shows a schematic configuration of the optical system of the fifth embodiment at the tele end. Fig. 5f shows the longitudinal spherical aberration curve, astigmatism curve and distortion curve of the optical system of the fifth embodiment at the tele end. As can be seen from fig. 5f, the optical system according to the fifth embodiment can achieve good imaging quality.

In a sixth embodiment of the present invention,

referring to fig. 6a to 6f, the optical system of the present embodiment, in order from an object side to an image side along an optical axis direction, includes:

The third lens element L3 with positive refractive power has an object-side surface S1 of the third lens element L3 being convex at paraxial region and an image-side surface S2 being convex at paraxial region; the object-side surface S5 of the third lens element L3 is convex at the circumference, and the image-side surface S6 is concave at the circumference.

The seventh lens element L7 with positive refractive power has an object-side surface S13 of the seventh lens element L7 being convex at paraxial region and an image-side surface S14 being concave at paraxial region; the object-side surface S13 of the seventh lens element L7 is convex at the circumference, and the image-side surface S14 is concave at the circumference.

Other structures of the sixth embodiment are the same as those of the first embodiment, and reference may be made thereto.

Tables 6a (1) -6 a (2) show tables of characteristics of the optical system of the present embodiment, and units of the Y radius, thickness, and focal length are all millimeters (mm).

TABLE 6a (1)

TABLE 6a (2)

Variable distance	D1	D2	D3	f(mm)	FNO	FOV(°)
							Short focal length position	-0.1170	-5.2486	-8.3714	16.2	3.11	28.1
Position of middle focus	-1.1478	-2.7993	-9.7699	19.8	3.68	22.9
							Position of long focus	-1.4461	-0.5996	-11.6913	24.2	4.83	18.7

In tables 6a (1) to 6a (2), the parameters have the same meanings as those of the first embodiment.

Table 6b shows the high-order term coefficients that can be used for each aspherical mirror surface in the sixth embodiment, wherein each aspherical mirror surface type can be defined by the formula given in the first embodiment.

TABLE 6b

Fig. 6a shows a schematic structural view of the optical system of the sixth embodiment at the short focal end. Fig. 6b shows a longitudinal spherical aberration curve, an astigmatism curve, and a distortion curve of the optical system of the sixth embodiment at the short focal end. As can be seen from fig. 6b, the optical system according to the sixth embodiment can achieve good image quality.

Fig. 6c shows a schematic structural view of the optical system of the sixth embodiment at the mid-focal end. Fig. 6d shows the longitudinal spherical aberration curve, astigmatism curve and distortion curve of the optical system of the sixth embodiment at the mid-focal end. As can be seen from fig. 6d, the optical system according to the sixth embodiment can achieve good image quality.

Fig. 6e shows a schematic configuration of the optical system of the sixth embodiment at the tele end. Fig. 6f shows the longitudinal spherical aberration curve, astigmatism curve and distortion curve of the optical system of the sixth embodiment at the tele end. As can be seen from fig. 6f, the optical system according to the sixth embodiment can achieve good imaging quality.

Table 7 shows values of Fc/Fd, FOVc/ImgH, TTL/(ATg2-ATg3), (R3+ R4)/(R7+ R8), F2/F234, F1/F567, F1/Fc, g3/(g1+ g2), and R14/F7 of the optical systems of the first to sixth embodiments.

TABLE 7

As can be seen from table 7, each example satisfies the following conditional expression: Fc/Fd >1.45, 4deg/mm < FOVc/ImgH <5.5deg/mm, 40< TTL/(ATg2-ATg3) <95, 2< (R3+ R4)/(R7+ R8) <8.5, F2/F234<7.5, 4< F1/F567<13, 1.9< F1/Fc <6, g3/(g1+ g2) <2, 2< R14/F7< 12.

The technical features of the above embodiments may be arbitrarily combined, and for the sake of brief description, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above examples only show some embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.

Claims

1. An optical system, comprising, in order from an object side to an image side along an optical axis:

a prism;

a first lens group with positive refractive power, the first lens group comprising a first lens;

the second lens group has negative refractive power and comprises a second lens, a third lens and a fourth lens;

a third lens group with positive refractive power, the third lens group comprising a fifth lens element, a sixth lens element and a seventh lens element;

2. The optical system according to claim 1, wherein the optical system satisfies the conditional expression: and Fc/Fd is greater than 1.45, wherein Fc is the focal length of the optical system at the long focal end, and Fd is the focal length of the optical system at the short focal end.

3. The optical system according to claim 1, wherein the optical system satisfies the conditional expression: 4deg/mm < FOVc/ImgH <5.5deg/mm, wherein FOVc is the maximum field angle of the optical system at the long focal end, and ImgH is half of the diagonal length of the effective imaging area of the imaging surface.

4. The optical system according to claim 1, wherein the optical system satisfies the conditional expression: 40< TTL/(ATg2-ATg3) <95, where TTL is the distance between the object-side surface of the first lens element and the image plane of the optical system on the optical axis, ATg2 is the total of the air spaces between the adjacent lens elements of the second lens element on the optical axis, and ATg3 is the total of the air spaces between the adjacent lens elements of the third lens element on the optical axis.

5. The optical system according to claim 1, wherein the optical system satisfies the conditional expression: 2< (R3+ R4)/(R7+ R8) <8.5, wherein R3 is the radius of curvature of the object-side surface of the second lens at the optical axis, R4 is the radius of curvature of the image-side surface of the second lens at the optical axis, R7 is the radius of curvature of the object-side surface of the fourth lens at the optical axis, and R8 is the radius of curvature of the image-side surface of the fourth lens at the optical axis.

6. The optical system according to claim 1, wherein the optical system satisfies the conditional expression: F2/F234<7.5, F2 is the focal length of the second lens, and F234 is the focal length of the second lens group.

7. The optical system according to claim 1, wherein the optical system satisfies the conditional expression: 4< F1/F567<13, wherein F1 is a focal length of the first lens group, and F567 is a focal length of the third lens group.

8. The optical system according to claim 1, wherein the optical system satisfies the conditional expression: 1.9< F1/Fc <6, where F1 is the focal length of the first lens group and Fc is the focal length of the optical system at the telephoto end.

9. The optical system according to claim 1, wherein the optical system satisfies the conditional expression: g3/(g1+ g2) <2, wherein g1 is the distance on the optical axis from the object-side surface of the first lens to the image-side surface of the first lens, g2 is the distance on the optical axis from the object-side surface of the second lens to the image-side surface of the fourth lens, and g3 is the distance on the optical axis from the object-side surface of the fifth lens to the image-side surface of the seventh lens.

10. The optical system according to claim 1, wherein the optical system satisfies the conditional expression: 2< R14/F7<12, wherein R14 is a radius of curvature of the image side surface of the seventh lens at the optical axis, and F7 is a focal length of the seventh lens.

11. An image pickup module comprising a lens barrel, an electro-optical element, and the optical system according to any one of claims 1 to 10, wherein the first lens to the seventh lens of the optical system are mounted in the lens barrel.

12. An electronic device comprising a housing and the camera module of claim 11, wherein the camera module is disposed within the housing.