CN213091989U

CN213091989U - Optical system, camera module and electronic equipment

Info

Publication number: CN213091989U
Application number: CN202021186571.6U
Authority: CN
Inventors: 谢晗; 刘彬彬; 李明; 邹海荣
Original assignee: Jiangxi Jingchao Optical Co Ltd
Current assignee: Jiangxi Jingchao Optical Co Ltd
Priority date: 2020-06-23
Filing date: 2020-06-23
Publication date: 2021-04-30
Anticipated expiration: 2030-06-23

Abstract

The utility model provides an optical system, camera module and electronic equipment. The optical system includes, in order from an object side to an image side in an optical axis direction: the first lens element with positive refractive power has a convex object-side surface at a paraxial region; the second lens element with negative refractive power has a convex object-side surface and a concave image-side surface; a third lens element with positive refractive power; a fourth lens element with negative refractive power; a fifth lens element with positive refractive power; a sixth lens element with negative refractive power; the optical system satisfies the conditional expression: TTL/ImgH < 1.35; ImgH >4 mm; wherein, TTL is the distance from the object side surface of the first lens to the imaging surface of the optical system on the optical axis, and ImgH is half of the diagonal length of the effective pixel area of the imaging surface. The utility model discloses make optical system can keep compact structure, the miniaturization of camera module when satisfying the requirement of high pixel and good image quality.

Description

Optical system, camera module and electronic equipment

Technical Field

The utility model belongs to the technical field of the optical imaging, especially, relate to an optical system, camera module and electronic equipment.

Background

In recent years, with the rise of portable electronic products having an imaging function, thinning and thinning have been becoming a trend, and thinning of cameras mounted on electronic products have also been progressing. However, due to the limitation of semiconductor process technology, it is difficult to continue to reduce the pixel size, and it is generally difficult to increase the pixel number by increasing the chip size, and it is difficult to achieve the light and thin optical system.

In order to bring better imaging experience to users and achieve the effect of high imaging quality, the number of lenses in the image capturing device needs to be increased, and the increase of the number of lenses causes difficulty in implementing miniaturization of the camera. Therefore, the existing camera cannot meet the requirements of high pixel and miniaturization at the same time.

SUMMERY OF THE UTILITY MODEL

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 utility model provides an optical system, the thing side to the image side along the optical axis direction contain in proper order: the first lens element with positive refractive power has a convex object-side surface at a paraxial region; the second lens element with negative refractive power has a convex object-side surface and a concave image-side surface; a third lens element with positive refractive power; a fourth lens element with negative refractive power; a fifth lens element with positive refractive power; a sixth lens element with negative refractive power; the optical system satisfies the conditional expression: TTL/ImgH < 1.35; ImgH >4 mm; wherein, TTL is the distance from the object side surface of the first lens to the imaging surface of the optical system on the optical axis, and ImgH is half of the diagonal length of the effective pixel area of the imaging surface. By reasonably configuring the surface shapes and the refractive powers of the first lens element to the sixth lens element, the optical system can meet the requirements of high pixel and good image quality, and meanwhile, the structure is kept compact and the size is reduced. When the optical system satisfies the relation TTL/ImgH <1.35, the total length of the optical system can be effectively reduced, and the system can be made thinner. When the optical system satisfies the relation ImgH >4mm, the chip size increases and the number of pixels increases. This application promotes like matter through carrying on high pixel chip.

Wherein the optical system satisfies the conditional expression: f3/f > 3; wherein f is an effective focal length of the optical system, and f3 is a focal length of the third lens. When the optical system satisfies the conditional expression, the third lens provides a small part of positive refractive power, and the total length of the optical system is further shortened by combining the light rays converged by the first lens.

Wherein the optical system satisfies the conditional expression: 0.8< f1/f < 0.95; wherein f1 is the focal length of the first lens, and f is the effective focal length of the optical system. When the optical system meets the conditional expression, the first lens provides most positive refractive power to form an image for the light converged by the optical system, the length of the optical system is controlled, and the field curvature is corrected.

Wherein the optical system satisfies the conditional expression: f5/f > 0.99; wherein f5 is the focal length of the fifth lens, and f is the effective focal length of the optical system. When the optical system meets the conditional expression, the fifth lens provides positive refractive power, and can be matched with the first lens and the third lens, so that higher imaging quality is ensured, and the total length of the optical system is further shortened.

Wherein the optical system satisfies the conditional expression: -0.6< R51/R52< -0.3; wherein R51 is a radius of curvature of the object-side surface of the fifth lens, and R52 is a radius of curvature of the image-side surface of the fifth lens. When the optical system meets the conditional expression, the fifth lens provides positive refractive power, is biconvex at the optical axis, can be matched with the first lens for imaging, corrects distortion, and is beneficial to shortening the length of the whole optical system.

Wherein the optical system satisfies the conditional expression: -0.9< f6/f < -0.8; wherein f6 is the focal length of the sixth lens, and f is the effective focal length of the optical system. When the optical system meets the conditional expression, the sixth lens provides negative refractive power, so that the back focal length can be effectively controlled to have enough length, a sufficient focusing range is ensured, and the photosensitive element is better matched.

Wherein the optical system satisfies the conditional expression: ET34<0.3 mm; ET45<0.36 mm; ET56<0.41 mm; wherein ET34 is the air space between the edge of the third lens optical effective diameter and the edge of the fourth lens optical effective diameter, ET45 is the air space between the edge of the fourth lens optical effective diameter and the edge of the fifth lens optical effective diameter, and ET56 is the air space between the edge of the fifth lens optical effective diameter and the edge of the sixth lens optical effective diameter. When the optical system meets the conditional expression, the values of ET34, ET45 and ET56 are reduced, a spacer-free structure is facilitated, and when ET34 is less than 0.2 mm; ET45<0.2 mm; when ET56 is less than 0.2mm, the spacer ring can be abandoned for direct arrangement, thereby saving cost and reducing weight.

Wherein the optical system satisfies the conditional expression: v2< 25; wherein v2 is the abbe number of the second lens with respect to the d-line (587.6 nm). When the optical system meets the conditional expression, the first lens is configured with enough positive refractive power, the generated chromatic aberration needs to be corrected by the negative lens, and the abbe number v2 of the second lens relative to the d line (587.6nm) is less than 25, so that the chromatic aberration can be effectively corrected, the system is balanced, and the high resolution is ensured.

Wherein the optical system satisfies the conditional expression: v4< 56; alternatively, v4< 30; wherein v4 is the abbe number of the fourth lens with respect to the d-line (587.6 nm). When the Abbe number v4 of the fourth lens of the optical system relative to the d line (587.6nm) is less than 56, the negative chromatic aberration of the system can be further corrected; when the abbe number v4 of the fourth lens of the optical system is less than 30, the chromatic aberration correction effect is better, and the resolution improvement effect is more obvious.

The utility model provides a camera module, include lens cone, electron photosensitive element and as above-mentioned optical system, optical system first lens extremely the sixth lens is installed in the lens cone, electron photosensitive element sets up optical system's image side is used for will passing first lens extremely the incidence of sixth lens is incided the last light signal of electron photosensitive element turns into the signal of telecommunication. This application is through installing this optical system's first lens to seventh lens in the camera module, and the face type and the power of refracting of each lens of rational configuration first lens to seventh lens for the camera module can keep compact structure, and the camera module is miniaturized when satisfying the requirement of high pixel and good image quality.

The utility model provides an electronic equipment, including casing and foretell camera module, camera module locates in the casing. This application is through setting up above-mentioned camera module in electronic equipment for electronic equipment can keep compact structure, and electronic equipment is miniaturized when satisfying the requirement of high pixel and good image quality.

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 these drawings without creative efforts.

FIG. 1a is a schematic structural diagram of an optical system of a first embodiment;

FIG. 1b is a longitudinal spherical aberration curve, an astigmatism curve and a distortion curve of the first embodiment;

FIG. 2a is a schematic structural diagram of an optical system of a second embodiment;

FIG. 2b is a longitudinal spherical aberration curve, an astigmatism curve and a distortion curve of the second embodiment;

FIG. 3a is a schematic structural diagram of an optical system of a third embodiment;

FIG. 3b is a longitudinal spherical aberration curve, an astigmatism curve and a distortion curve of the third embodiment;

FIG. 4a is a schematic structural diagram of an optical system of a fourth embodiment;

FIG. 4b is a longitudinal spherical aberration curve, an astigmatism curve and a distortion curve of the fourth embodiment;

FIG. 5a is a schematic structural diagram of an optical system of a fifth embodiment;

FIG. 5b is a longitudinal spherical aberration curve, an astigmatism curve and a distortion curve of the fifth embodiment;

FIG. 6a is a schematic structural diagram of an optical system of a sixth embodiment;

fig. 6b is a longitudinal spherical aberration curve, an astigmatism curve and a distortion curve of the sixth embodiment.

FIG. 7a is a schematic structural diagram of an optical system of a seventh embodiment;

fig. 7b is a longitudinal spherical aberration curve, an astigmatism curve and a distortion curve of the seventh embodiment.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

The embodiment of the application provides a camera module, this camera module include lens cone, electron photosensitive element and the utility model provides an optical system, optical system's first lens are installed in the lens cone to the sixth lens, electron photosensitive element sets up optical system's image side is used for will passing first lens extremely the incidence of sixth lens the light of the thing on the electron photosensitive element converts the signal of telecommunication of image into. The electron sensor may be a Complementary Metal Oxide Semiconductor (CMOS) or a Charge-coupled Device (CCD). The camera module can be an independent camera 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 sixth lens in the camera module, and the face type and the power of refracting of each lens of rational configuration first lens to sixth lens for the camera module can keep compact structure, and the camera module is miniaturized when satisfying the requirement of high pixel and good image quality.

The embodiment of the application provides an electronic device, which comprises a shell and a camera module. 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 is through setting up the camera module in electronic equipment for electronic equipment can keep compact structure, and electronic equipment is miniaturized when satisfying the requirement of high pixel and good image quality.

The present disclosure provides an optical system, which includes, in order from an object side to an image side along an optical axis, a stop, a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element and a sixth lens element. In the first to sixth lenses, any two adjacent lenses may have an air space therebetween.

Specifically, the specific shape and structure of the six lenses are as follows:

the first lens element with positive refractive power has a convex object-side surface at a paraxial region; the second lens element with negative refractive power has a convex object-side surface and a concave image-side surface; a third lens element with positive refractive power; a fourth lens element with negative refractive power; a fifth lens element with positive refractive power; a sixth lens element with negative refractive power; the optical system satisfies the conditional expression: TTL/ImgH < 1.35; ImgH >4 mm; wherein, TTL is the distance from the object side surface of the first lens to the imaging surface of the optical system on the optical axis, and ImgH is half of the diagonal length of the effective pixel area of the imaging surface. By reasonably configuring the surface shapes and the refractive powers of the first lens element to the sixth lens element, the optical system can meet the requirements of high pixel and good image quality, and meanwhile, the structure is kept compact and the size is reduced. When the optical system satisfies the relation TTL/ImgH <1.35, the total length of the optical system can be effectively reduced, and the system can be made thinner. When the optical system satisfies the relation ImgH >4mm, the chip size increases and the number of pixels increases. This application promotes like matter through carrying on high pixel chip.

In a specific embodiment, the optical system satisfies the conditional expression: f3/f > 3; wherein f is an effective focal length of the optical system, and f3 is a focal length of the third lens. When the optical system satisfies the conditional expression, the third lens provides a small part of positive refractive power, and the total length of the optical system is further shortened by combining the light rays converged by the first lens.

In a specific embodiment, the optical system satisfies the conditional expression: 0.8< f1/f < 0.95; wherein f1 is the focal length of the first lens, and f is the effective focal length of the optical system. When the optical system meets the conditional expression, the first lens provides most positive refractive power to form an image for the light converged by the optical system, the length of the optical system is controlled, and the field curvature is corrected.

In a specific embodiment, the optical system satisfies the conditional expression: f5/f > 0.99; wherein f5 is the focal length of the fifth lens, and f is the effective focal length of the optical system. When the optical system meets the conditional expression, the fifth lens provides positive refractive power, and can be matched with the first lens and the third lens, so that higher imaging quality is ensured, and the total length of the optical system is further shortened.

In a specific embodiment, the optical system satisfies the conditional expression: -0.6< R51/R52< -0.3; wherein R51 is a radius of curvature of the object-side surface of the fifth lens, and R52 is a radius of curvature of the image-side surface of the fifth lens. When the optical system meets the conditional expression, the fifth lens provides positive refractive power, is biconvex at the optical axis, can be matched with the first lens for imaging, corrects distortion, and is beneficial to shortening the length of the whole optical system.

In a specific embodiment, the optical system satisfies the conditional expression: -0.9< f6/f < -0.8; wherein f6 is the focal length of the sixth lens, and f is the effective focal length of the optical system. When the optical system meets the conditional expression, the sixth lens provides negative refractive power, so that the back focal length can be effectively controlled to have enough length, a sufficient focusing range is ensured, and the photosensitive element is better matched.

In a specific embodiment, the optical system satisfies the conditional expression: ET34<0.3 mm; ET45<0.36 mm; ET56<0.41 mm; wherein ET34 is the air space between the edge of the third lens optical effective diameter and the edge of the fourth lens optical effective diameter, ET45 is the air space between the edge of the fourth lens optical effective diameter and the edge of the fifth lens optical effective diameter, and ET56 is the air space between the edge of the fifth lens optical effective diameter and the edge of the sixth lens optical effective diameter. When the optical system meets the conditional expression, the values of ET34, ET45 and ET56 are reduced, a spacer-free structure is facilitated, and when ET34 is less than 0.2 mm; ET45<0.2 mm; when ET56 is less than 0.2mm, the spacer ring can be abandoned for direct arrangement, thereby saving cost and reducing weight.

In a specific embodiment, the optical system satisfies the conditional expression: v2< 25; wherein v2 is the abbe number of the second lens with respect to the d-line (587.6 nm). When the optical system meets the conditional expression, the first lens is configured with enough positive refractive power, the generated chromatic aberration needs to be corrected by the negative lens, and the abbe number v2 of the second lens relative to the d line (587.6nm) is less than 25, so that the chromatic aberration can be effectively corrected, the system is balanced, and the high resolution is ensured.

In a specific embodiment, the optical system satisfies the conditional expression: v4< 56; alternatively, v4< 30; wherein v4 is the abbe number of the fourth lens with respect to the d-line (587.6 nm). When the Abbe number v4 of the fourth lens of the optical system relative to the d line (587.6nm) is less than 56, the negative chromatic aberration of the system can be further corrected; when the fourth lens of the optical system has an abbe number v4<30 relative to the d-line (587.6nm), the chromatic aberration correction effect is better, and the resolution improvement effect is more remarkable.

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

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

the first lens element L1 with positive refractive power has a convex object-side surface S1 at paraxial region and a concave image-side surface S2 at paraxial region; the object-side surface S1 of the first lens element 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 a convex object-side surface S3 and a concave image-side surface S4 at paraxial region; the object-side surface S3 of the second lens element 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 a convex object-side surface S5 and a concave image-side surface S6 at paraxial region; the object-side surface S5 of the third lens element is concave 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 and a convex image-side surface S8 at a paraxial region; the object-side surface S7 of the fourth lens element is concave at the circumference, and the image-side surface S8 is convex at the circumference.

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

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

The first lens element L1 through the sixth lens element L6 are all made of plastic.

Further, the optical system includes a stop STO, an infrared filter L7, and an image plane S15. The stop STO is provided on the side of the first lens L1 away from the second lens L2, and controls the amount of light entering. In other embodiments, the stop STO can be disposed between two adjacent lenses, or on other lenses. The infrared filter L7 is disposed on the image side of the sixth lens L6, and includes an object side surface S13 and an image side surface S14, and the infrared filter L7 is configured to filter infrared light, so that the light incident on the image surface S15 is visible light, and the wavelength of the visible light is 380nm-780 nm. The infrared filter L7 is made of glass, and may be coated with a film. The image plane S15 is a plane on which an image formed by the light of the subject passing through the optical system is located.

Table 1a shows a table of characteristics of the optical system of the present embodiment, and the units of the Y radius, thickness, and focal length are all millimeters (mm).

TABLE 1a

Wherein f is an effective 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 from an object side surface of the first lens to an imaging surface of the optical system on an optical axis.

In the present embodiment, the object-side surface and the image-side surface of any one of the first lens L1 through 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 inverse of radius R of Y in table 1a 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 that can be used for each of the aspherical mirrors S1-S16 in the first embodiment.

TABLE 1b

Fig. 1b shows a longitudinal spherical aberration curve, an astigmatism curve and a distortion curve of the optical system of the first embodiment. 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.

Second embodiment

Referring to fig. 2a and fig. 2b, 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 a convex object-side surface S1 at paraxial region and a concave image-side surface S2 at paraxial region; the object-side surface S1 and the image-side surface S2 of the first lens element are convex at the periphery.

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

Table 2a shows a table of characteristics of the optical system of the present embodiment, and the units of the Y radius, thickness, and focal length are all millimeters (mm).

TABLE 2a

Wherein the values of the parameters in Table 2a 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. 2b shows a longitudinal spherical aberration curve, an astigmatism curve and a distortion curve of the optical system of the second embodiment. As can be seen from fig. 2b, the optical system according to the second embodiment can achieve good imaging quality.

Third embodiment

Referring to fig. 3a and 3b, 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 a convex object-side surface S1 and a concave image-side surface S2 at paraxial region; the object-side surface S5 of the third lens element is concave 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 is concave at the circumference, and the image-side surface S8 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.

Table 3a shows a table of characteristics of the optical system of the present embodiment, and the units of the Y radius, thickness, and focal length are all millimeters (mm).

TABLE 3a

Wherein the values of the parameters in Table 3a 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. 3b shows a longitudinal spherical aberration curve, an astigmatism curve and a distortion curve of the optical system of the third embodiment. As can be seen from fig. 3b, the optical system according to the third embodiment can achieve good imaging quality.

Fourth embodiment

Referring to fig. 4a and 4b, 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 a convex object-side surface S1 at paraxial region and a convex image-side surface S2 at paraxial region; the object-side surface S5 of the third lens element is concave 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 and a convex image-side surface S8 at a paraxial region; the object-side surface S7 of the fourth lens element is concave at the circumference, and the image-side surface S8 is concave at the circumference.

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

Table 4a shows a table of characteristics of the optical system of the present embodiment, and the units of the Y radius, thickness, and focal length are all millimeters (mm).

TABLE 4a

Wherein the values of the parameters in Table 4a are the same as those of 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. 4b shows a longitudinal spherical aberration curve, an astigmatism curve and a distortion curve of the optical system of the fourth embodiment. As can be seen from fig. 4b, the optical system according to the fourth embodiment can achieve good imaging quality.

Fifth embodiment

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

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

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

Table 5a shows a table of characteristics of the optical system of the present embodiment, and the units of the Y radius, thickness, and focal length are all millimeters (mm).

TABLE 5a

Wherein the meanings of the parameters in Table 5a 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. 5b shows a longitudinal spherical aberration curve, an astigmatism curve and a distortion curve of the optical system of the fifth embodiment. As can be seen from fig. 5b, the optical system according to the fifth embodiment can achieve good image quality.

Sixth embodiment

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

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

Table 6a shows a table of characteristics of the optical system of the present embodiment, and the units of the Y radius, thickness, and focal length are all millimeters (mm).

TABLE 6a

Wherein the values of the parameters in Table 6a are the same 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. 6b shows a longitudinal spherical aberration curve, an astigmatism curve and a distortion curve of the optical system of the sixth embodiment. As can be seen from fig. 6b, the optical system according to the sixth embodiment can achieve good image quality.

In a seventh embodiment, the first and second embodiments,

referring to fig. 7a and 7b, 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 a convex object-side surface S1 at paraxial region and a concave image-side surface S2 at paraxial region; the object-side surface S1 of the first lens element is convex at its circumference, and the image-side surface S2 is concave.

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

Table 7a shows a table of characteristics of the optical system of the present embodiment, and the units of the Y radius, thickness, and focal length are all millimeters (mm).

TABLE 7a

Wherein the meanings of the parameters in Table 7a are the same as those of the first embodiment.

Table 7b shows the high-order term coefficients that can be used for each aspherical mirror surface in the seventh embodiment, wherein each aspherical mirror surface type can be defined by the formula given in the first embodiment.

TABLE 7b

Fig. 7b shows a longitudinal spherical aberration curve, an astigmatism curve, and a distortion curve of the optical system of the seventh embodiment. As can be seen from fig. 7b, the optical system according to the seventh embodiment can achieve good image quality.

Table 8 shows values of TTL/ImgH, f3/f, f1/f, f5/f, R51/R52, f6/f, ET34, ET45, ET56, v2, and v4 of the optical systems of the first to seventh embodiments.

TABLE 8

	TTL/ImgH	ImgH	f3/f	f1/f	f5/f	R51/R52
							First embodiment	1.216	4.760	9.038	0.884	1.228	-0.538
Second embodiment	1.315	4.410	4.055	0.867	1.246	-0.462
							Third embodiment	1.291	4.410	15.144	0.901	1.040	-0.514
Fourth embodiment	1.293	4.410	3.309	0.887	1.062	-0.331
							Fifth embodiment	1.326	4.410	3.613	0.827	0.992	-0.447
Sixth embodiment	1.327	4.410	3.291	0.811	1.048	-0.342
							Seventh embodiment	1.338	4.410	3.075	0.826	1.029	-0.446
	f6/f	ET34	ET45	ET56	v2	v4
							First embodiment	-0.806	0.121	0.356	0.408	19.244	20.377
Second embodiment	-0.806	0.23	0.062	0.363	19.244	37.4
							Third embodiment	-0.801	0.293	0.05	0.462	19.244	55.924
Fourth embodiment	-0.899	0.216	0.092	0.5	19.244	55.924
							Fifth embodiment	-0.864	0.196	0.108	0.254	19.244	24.02
Sixth embodiment	-0.853	0.198	0.141	0.2	19.244	27.68
							Seventh embodiment	-0.832	0.199	0.155	0.185	19.244	27.21

As can be seen from Table 8, each example satisfies the following conditional expressions TTL/ImgH <1.35, ImgH >4mm, f3/f >3, 0.8< f1/f <0.95, f5/f >0.99, -0.6< R51/R52< -0.3, -0.9< f6/f < -0.8, ET34<0.3mm, ET45<0.36mm, ET56<0.41mm, v2<25, v4< 56.

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 being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above examples only represent some embodiments of the present invention, and the description thereof is more specific and detailed, but not to be construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, without departing from the spirit of the present invention, several variations and modifications can be made, which are 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 in an optical axis direction:

the first lens element with positive refractive power has a convex object-side surface at a paraxial region;

the second lens element with negative refractive power has a convex object-side surface and a concave image-side surface;

a third lens element with positive refractive power;

a fourth lens element with negative refractive power;

a fifth lens element with positive refractive power;

a sixth lens element with negative refractive power;

the optical system satisfies the conditional expression: TTL/ImgH < 1.35; ImgH >4 mm; wherein, TTL is the distance from the object side surface of the first lens to the imaging surface of the optical system on the optical axis, and ImgH is half of the diagonal length of the effective pixel area of the imaging surface.

2. The optical system according to claim 1, wherein the optical system satisfies the conditional expression: f3/f > 3; wherein f is an effective focal length of the optical system, and f3 is a focal length of the third lens.

3. The optical system according to claim 1, wherein the optical system satisfies the conditional expression: 0.8< f1/f < 0.95; wherein f1 is the focal length of the first lens, and f is the effective focal length of the optical system.

4. The optical system according to claim 1, wherein the optical system satisfies the conditional expression: f5/f > 0.99; wherein f5 is the focal length of the fifth lens, and f is the effective focal length of the optical system.

5. The optical system according to claim 1, wherein the optical system satisfies the conditional expression: -0.6< R51/R52< -0.3; wherein R51 is a radius of curvature of the object-side surface of the fifth lens, and R52 is a radius of curvature of the image-side surface of the fifth lens.

6. The optical system according to claim 1, wherein the optical system satisfies the conditional expression: -0.9< f6/f < -0.8; wherein f6 is the focal length of the sixth lens, and f is the effective focal length of the optical system.

7. The optical system according to claim 1, wherein the optical system satisfies the conditional expression: ET34<0.3 mm; ET45<0.36 mm; ET56<0.41 mm; wherein ET34 is the air space between the edge of the third lens optical effective diameter and the edge of the fourth lens optical effective diameter, ET45 is the air space between the edge of the fourth lens optical effective diameter and the edge of the fifth lens optical effective diameter, and ET56 is the air space between the edge of the fifth lens optical effective diameter and the edge of the sixth lens optical effective diameter.

8. The optical system according to claim 1, wherein the optical system satisfies the conditional expression: v2< 25; wherein v2 is the abbe number of the second lens with respect to the d-line (587.6 nm).

9. The optical system according to claim 1, wherein the optical system satisfies the conditional expression: v4< 56; alternatively, v4< 30; wherein v4 is the abbe number of the fourth lens with respect to the d-line (587.6 nm).

10. A camera module, comprising a lens barrel, an electronic photosensitive element and the optical system according to any one of claims 1 to 9, wherein the first lens to the sixth lens of the optical system are mounted in the lens barrel, and the electronic photosensitive element is disposed on an image side of the optical system and is configured to convert optical signals, which pass through the first lens to the sixth lens and are incident on the electronic photosensitive element, into electrical signals.

11. An electronic device comprising a housing and the camera module of claim 10, wherein the camera module is disposed within the housing.