CN112034591A

CN112034591A - Optical system, camera module and electronic equipment

Info

Publication number: CN112034591A
Application number: CN202010976667.0A
Authority: CN
Inventors: 刘彬彬; 邹海荣; 李明
Original assignee: OFilm Tech Co Ltd
Current assignee: Nanchang OFilm Precision Optical Products Co Ltd; OFilm Group Co Ltd
Priority date: 2020-09-16
Filing date: 2020-09-16
Publication date: 2020-12-04

Abstract

The invention provides an optical system, a camera module and an electronic device, wherein the optical system comprises the following components in sequence from an object side to an image side along a first optical axis direction: the first lens element with positive refractive power has a convex object-side surface and a flat image-side surface; the prism is used for turning the light path to enable the light path to be turned to a second optical axis by the first optical axis, and the first optical axis is intersected with the second optical axis; the object side to the image side along the second optical axis direction sequentially comprises: a second lens element with positive refractive power having a convex object-side surface and a convex image-side surface; a third lens element with refractive power having a concave object-side surface at a paraxial region; a fourth lens element with refractive power; a fifth lens element with refractive power; a sixth lens element with negative refractive power having a convex object-side surface and a concave image-side surface; the seventh lens element with negative refractive power. The surface shape and the refractive power of each lens are reasonably configured, so that the structure is miniaturized while a better telephoto effect is met.

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

The manufacturing technology of electronic products such as smart phones and flat panels is continuously developed, and the lens which is one of important basic parts of image data acquisition is also under diversified development, along with the requirement of the market on high imaging quality of camera shooting, the lens needs to have a better telephoto effect, however, the length of the traditional telephoto lens is longer, and the requirement of miniaturization is difficult to meet.

Therefore, the periscopic lens has come to work, and how to make the periscopic lens have a better telephoto effect and meet the requirement of miniaturization is a technical problem which needs to be solved urgently.

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.

In order to achieve the purpose of the application, the application provides the following technical scheme:

in a first aspect, the present application provides an optical system, in order from an object side to an image side along a first optical axis direction, comprising: the first lens element with positive refractive power has a convex object-side surface and a flat image-side surface; the prism is used for turning the light path so that the light path is turned to a second optical axis by the first optical axis, and the first optical axis is intersected with the second optical axis; the object side to the image side along the second optical axis direction sequentially comprises: the second lens element with positive refractive power has a convex object-side surface paraxial region and a convex image-side surface paraxial region; the third lens element with refractive power has a concave object-side surface at the paraxial region; a fourth lens element with refractive power; a fifth lens element with refractive power; the sixth lens element with negative refractive power has a convex object-side surface and a concave image-side surface; the seventh lens element with negative refractive power. Through reasonable configuration of the surface shapes and the refractive powers of the first lens element to the seventh lens element, the optical system can achieve a miniaturized structure while satisfying a better telephoto effect.

In one embodiment, at least one surface of at least one of the first lens to the seventh lens is an aspherical surface. Under the structure, the optical system can realize the miniaturization of the structure while meeting the better telephoto effect.

In one embodiment, the optical system satisfies the conditional expression: 1.6< TTL/(ImgH × 2) < 2.5; 11 ° < HFOV <16 °; 0.6< DL/TTL < 0.8; wherein, TTL is a distance between an object-side surface of the second lens element and an image plane of the optical system on the second optical axis, ImgH is a half of a diagonal length of an effective imaging area of the optical system on the image plane, HFOV is a half of a maximum field angle of the optical system, and DL is a distance between the object-side surface of the second lens element and an image-side surface of the seventh lens element on the second optical axis. When the optical system meets the conditional expression, reasonable structural layout is carried out on the second lens to the seventh lens, so that the ratio of the height of the lens to the imaging surface is in a small range, the optical system is miniaturized, the space of the lens part is reduced on the basis of realizing miniaturization, and the layout of the module structure end is facilitated.

In one embodiment, the optical system satisfies the conditional expression: 0.9< TTL/f < 1.2; wherein, TTL is a distance from an object-side surface of the second lens element to an image plane of the optical system on the second optical axis, and f is an effective focal length of the optical system. When the optical system satisfies the above conditional expression, a lower lens height can be provided in the HFOV <16 °, making the optical system more easily implanted in a portable device. Meanwhile, the aspheric surface is used, so that the ratio of TTL to f is in a smaller numerical range, and under the condition of realizing telephoto photography, the optical system is favorable for balancing aberrations such as chromatic aberration and spherical aberration, and good imaging quality is obtained.

In one embodiment, the optical system satisfies the conditional expression: EFY (L2-L7) >10 mm; and EFY (L2-L7) is the focal length of the rear lens group consisting of the second lens to the seventh lens. When the optical system meets the conditional expression, namely, the focal power of the first lens and the rear lens group is reasonably configured, the light entering through the first lens is effectively balanced and corrected through the rear lens group, and the generated aberration and marginal light are effectively converged, so that the optical system can have a better telephoto effect while the optical system is ensured to be compact and miniaturized.

In one embodiment, the optical system satisfies the conditional expression: T56/T67< 0.25; wherein T56 is a distance between an image-side surface of the fifth lens element and an object-side surface of the sixth lens element on the second optical axis, and T67 is a distance between an image-side surface of the sixth lens element and an object-side surface of the seventh lens element on the second optical axis. When the optical system meets the conditional expression, namely the position relations between the fifth lens and the sixth lens and between the sixth lens and the seventh lens are reasonably configured, the length of the optical system can be effectively compressed, the direction change of light rays entering the optical system is slowed down, and the intensity of stray light is favorably reduced.

In one embodiment, the optical system satisfies the conditional expression: l f2/f1 l < 0.3; wherein f1 is the effective focal length of the first lens, and f2 is the effective focal length of the second lens. When the optical system meets the conditional expression, namely the sizes and the refractive powers of the first lens and the second lens are reasonably configured, the larger spherical aberration generated by the front lens group can be balanced, the integral resolving power of the optical system is improved, the refractive power configuration of the rear end of the optical system is controlled, the peripheral aberration correction of the optical system is strengthened, meanwhile, the size compression is facilitated, and the optical system is miniaturized.

In one embodiment, the optical system satisfies the conditional expression: V2-V4| > 30; wherein V2 is the second lens Abbe number, and V4 is the fourth lens Abbe number. When the optical system meets the conditional expression, the abbe numbers of the second lens and the fourth lens are reasonably configured, which is beneficial to chromatic aberration correction and performance guarantee of the optical system.

In a second aspect, the present application further provides a camera module, which includes a lens barrel, an electronic photosensitive element, and an optical system in any one of the embodiments of the first aspect, wherein the first to seventh lenses and the prism 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 an optical signal of an object, which passes through the first to seventh lenses and is incident on the electronic photosensitive element, into an electrical signal of an image. Through install above-mentioned optical system in the camera module, enable the camera module can be when satisfying better telephoto effect, realizes that the structure is miniaturized.

In a third aspect, the present application further provides an electronic device, which includes a housing and the camera module of the second aspect, wherein the camera module is disposed in the housing. Through set up the camera module of the second aspect in electronic equipment, enable electronic equipment realizes that the structure is miniaturized when satisfying better telephoto effect.

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 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 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 provided by the embodiment of the invention, wherein a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a prism 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 optical signals of objects which penetrate through the first lens, the prism, 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. Through installing this optical system's first lens to seventh lens and prism in camera module, the face type and the power of refracting of each lens of rational configuration first lens to seventh lens for the camera module that this application embodiment provided can realize the structure miniaturization when satisfying better telephoto effect.

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. Through set up the camera module that this application embodiment provided in electronic equipment, make electronic equipment can satisfy better when the effect of taking a distance, realize that the structure is miniaturized.

An embodiment of the present disclosure provides an optical system, which includes a first lens and a prism in sequence from an object side to an image side along a first optical axis, where the prism is configured to turn a light path, so that the light path has a first optical axis (i) and turns to a second optical axis (ii), the first optical axis (i) intersects the second optical axis, and the optical system includes a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens in sequence from the object side to the image side along the second optical axis (ii). In the first to seventh lenses, any two adjacent lenses may have an air space therebetween.

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

the first lens element with positive refractive power has a convex object-side surface and a flat image-side surface; the second lens element with positive refractive power has a convex object-side surface and a convex image-side surface; the third lens element with refractive power has a concave object-side surface at paraxial region; a fourth lens element with refractive power; a fifth lens element with refractive power; the sixth lens element with negative refractive power has a convex object-side surface and a concave image-side surface; the seventh lens element with negative refractive power. Through the reasonable configuration of the surface shapes and the refractive powers of the first lens element to the seventh lens element, the optical system of the present application can achieve a compact structure while satisfying a better telephoto effect.

In one embodiment, the optical system satisfies the conditional expression: 1.6< TTL/(ImgH × 2) < 2.5; 11 ° < HFOV <16 °; 0.6< DL/TTL < 0.8; wherein, TTL is a distance between an object-side surface of the second lens element and an imaging surface of the optical system on the second optical axis, ImgH is a half of a diagonal length of an effective imaging area of the optical system on the imaging surface, HFOV is a half of a maximum field angle of the optical system, and DL is a distance between the object-side surface of the second lens element and an image-side surface of the seventh lens element on the second optical axis. When optical system satisfies above-mentioned conditional expression, carry out reasonable structural layout to second lens to seventh lens promptly, make camera lens height and imaging surface ratio in a less scope to make optical system realize miniaturizing, and on the basis of realizing the miniaturization, reduce the space of lens part, be favorable to the overall arrangement of module structure end.

In one embodiment, the optical system satisfies the conditional expression: 0.9< TTL/f < 1.2; wherein, TTL is a distance from the object side surface of the second lens element to the imaging surface of the optical system on the second optical axis @, and f is an effective focal length of the optical system. When the optical system satisfies the above conditional expression, a lower lens height can be provided in the HFOV <16 °, making it easier to implant the optical system in a portable device. Meanwhile, the aspheric surface is used, so that the ratio of TTL to f is in a smaller numerical range, and under the condition of realizing telephoto photography, the optical system is favorable for balancing aberration such as chromatic aberration and spherical aberration, and good imaging quality is obtained.

In one embodiment, the optical system satisfies the conditional expression: EFY (L2-L7) >10 mm; the EFY (L2-L7) is the focal length of the rear lens group consisting of the second lens to the seventh lens. When the optical system meets the conditional expression, namely, the focal power of the first lens and the rear lens group is reasonably configured, the light entering through the first lens is effectively balanced and corrected through the rear lens group, the generated aberration is corrected, and the marginal light is effectively converged, so that the optical system has a good telephoto effect while the compactness and the miniaturization of the optical system are ensured.

In one embodiment, the optical system satisfies the conditional expression: T56/T67< 0.25; wherein, T56 is a distance between the image-side surface of the fifth lens element and the object-side surface of the sixth lens element along the second optical axis @, and T67 is a distance between the image-side surface of the sixth lens element and the object-side surface of the seventh lens element along the second optical axis @. When the optical system meets the conditional expression, namely the position relations between the fifth lens and the sixth lens and between the sixth lens and the seventh lens are reasonably configured, the length size of the optical system can be effectively compressed, the direction change of light rays entering the optical system is slowed down, and the stray light intensity is favorably reduced.

In one embodiment, the optical system satisfies the conditional expression: l f2/f1 l < 0.3; wherein f1 is the effective focal length of the first lens, and f2 is the effective focal length of the second lens. When the optical system meets the conditional expression, namely the sizes and the refractive powers of the first lens and the second lens are reasonably configured, the larger spherical aberration generated by the front lens group can be balanced, the integral resolving power of the optical system is improved, the configuration of the refractive power at the rear end of the optical system is controlled, the peripheral aberration correction of the optical system is strengthened, meanwhile, the size compression is facilitated, and the miniaturization of the optical system is realized.

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:

a first lens L1 with positive refractive power, the first lens L1 having an object-side surface S1 convex paraxially and circumferentially, the first lens L1 having an image-side surface S2 planar paraxially and circumferentially;

the prism Lp is used for deflecting the light path;

a second lens element L2 with positive refractive power, the second lens element L2 having a convex object-side surface S3 at paraxial and peripherical positions, and the second lens element L2 having a convex image-side surface S4 at paraxial and peripherical positions;

the third lens L3 with negative bending force has a concave object-side surface S5 of the third lens L3 at the paraxial region and the peripheral region, a convex image-side surface S6 of the third lens L3 at the paraxial region, and a concave image-side surface S6 at the peripheral region;

the fourth lens element L4 with positive refractive power has a concave object-side surface S7 of the fourth lens element L4 at a paraxial region thereof, a convex object-side surface S7 at a paraxial region thereof, a convex image-side surface S8 of the fourth lens element L4 at a paraxial region thereof, and a concave image-side surface S8 at a peripheral region thereof;

a fifth lens element L5 with negative dioptric power, the fifth lens element L5 having an object-side surface S9 that is convex paraxial and peripherical, and the fifth lens element L5 having an image-side surface S10 that is concave paraxial and peripherical;

a sixth lens element L6 with negative dioptric power, the sixth lens element L6 having an object-side surface S11 that is convex paraxial and peripherical, and the sixth lens element L6 having an image-side surface S12 that is concave paraxial and peripherical;

the seventh lens element L7 has negative refractive power, the object-side surface S13 of the seventh lens element L7 is convex near the axis, the object-side surface S13 is concave near the circumference, the image-side surface S14 of the seventh lens element L7 is concave near the axis, and the image-side surface S14 is convex near the circumference.

Of the above-described first lens L1 to seventh lens L7, at least one lens is made of a first plastic material, and at least one lens is made of a second plastic material, wherein the first plastic material and the second plastic material have different optical characteristics.

Further, the optical system includes a stop STO, an infrared filter L8, and an image forming surface S17. The stop STO is provided on the side of the second lens L2 away from the third lens L3 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 entering the image plane 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. S17 denotes an image forming surface of the optical system, and the area mapped on the effective pixel region of the electrophotographic device is an effective image forming region. It will be appreciated that the imaging plane overlaps but is not coincident with the electro-optic element, and in one particular embodiment, the imaging plane in the handset is a circumscribed circle of the active pixel area.

Table 1a shows a table of characteristics of the optical system of the present embodiment in which data of focal length is obtained using light having a wavelength of 555nm, data of refractive index and dispersion coefficient is obtained using light having a wavelength of 587.56nm, and the units of radius of curvature and thickness are 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, TTL is a distance from an object side surface of the second lens to an imaging surface of the optical system on a second optical axis, ImgH is a half of a diagonal length of an effective imaging area of the optical system on the imaging surface, and DL is a distance from an object side surface of the second lens to an image side surface of the seventh lens on the second optical axis.

In the present embodiment, at least one surface of at least one of the first lens L1 to the seventh lens L7 is an aspheric surface, 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 prism Lp is used for deflecting the light path;

a third lens element L3 with negative dioptric power, the third lens element L3 having an object-side surface S5 that is concave paraxially or circumferentially and a third lens element L3 having an image-side surface S6 that is convex paraxially or circumferentially;

a fourth lens element L4 with negative dioptric power, the fourth lens element L4 having an object-side surface S7 that is convex paraxial and peripherical, and the fourth lens element L4 having an image-side surface S8 that is concave paraxial and peripherical;

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 in which data of focal length is obtained using light having a wavelength of 555nm, data of refractive index and dispersion coefficient is obtained using light having a wavelength of 587.56nm, and the units of radius of curvature and thickness are 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 prism Lp is used for deflecting the light path;

a fourth lens element L4 with positive refractive power, the fourth lens element L4 having an object-side surface S7 that is convex paraxially and circumferentially, and the fourth lens element L4 having an image-side surface S8 that is concave paraxially and circumferentially;

the sixth lens L6 has positive bending force, the paraxial part and the near-circumference part of an object side surface S11 of the sixth lens L6 are convex surfaces, and the paraxial part and the near-circumference part of an image side surface S12 of the sixth lens L6 are concave surfaces;

the seventh lens element L7 with negative refractive power has a concave object-side surface S13 of the seventh lens element L7 near the axis and near the circumference, and a convex image-side surface S14 near the axis and near the circumference of the seventh lens element L7.

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 in which data of focal length is obtained using light having a wavelength of 555nm, data of refractive index and dispersion coefficient is obtained using light having a wavelength of 587.56nm, and the units of radius of curvature and thickness are 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 prism Lp is used for deflecting the light path;

the third lens L3 has positive bending force, the paraxial part and the near-circumference part of an object side surface S5 of the third lens L3 are concave, and the paraxial part and the near-circumference part of an image side surface S6 of the third lens L3 are convex;

the fourth lens L4 with negative bending force has a concave object-side surface S7 of the fourth lens L4 at the paraxial region and the peripheral region, a convex image-side surface S8 of the fourth lens L4 at the paraxial region, and a concave image-side surface S8 at the peripheral region;

the fifth lens element L5 with positive refractive power has a concave object-side surface S9 of the fifth lens element L5 at a paraxial region thereof, a convex object-side surface S9 at a paraxial region thereof, a convex image-side surface S10 of the fifth lens element L5 at a paraxial region thereof, and a concave image-side surface S10 at a peripheral region thereof;

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 in which data of focal length is obtained using light having a wavelength of 555nm, data of refractive index and dispersion coefficient is obtained using light having a wavelength of 587.56nm, and the units of radius of curvature and thickness are 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 prism Lp is used for deflecting the light path;

the fifth lens element L5 with negative refractive power has a concave object-side surface S9 of the fifth lens element L5 at a paraxial region thereof, a convex object-side surface S9 at a paraxial region thereof, a convex image-side surface S10 of the fifth lens element L5 at a paraxial region thereof, and a concave image-side surface S10 at a paraxial region thereof;

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 in which data of focal length is obtained using light having a wavelength of 555nm, data of refractive index and dispersion coefficient is obtained using light having a wavelength of 587.56nm, and the units of radius of curvature and thickness are 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:

the prism Lp is used for deflecting the light path;

the fifth lens element L5 with positive refractive power has a convex object-side surface S9 of the fifth lens element L5 at a paraxial and peripherical position, a convex image-side surface S10 of the fifth lens element L5 at a paraxial position, and a concave image-side surface S10 at a peripherical position;

the seventh lens element L7 has negative refractive power, and the object-side surface S13 of the seventh lens element L7 is concave at the paraxial region and at the paraxial region, and the image-side surface S14 of the seventh lens element L7 is concave at the paraxial region and convex at the peripheral region, and the image-side surface S14 is convex at the peripheral region.

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 in which data of focal length is obtained using light having a wavelength of 555nm, data of refractive index and dispersion coefficient is obtained using light having a wavelength of 587.56nm, and the units of radius of curvature and thickness are 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.

Seventh embodiment

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 prism Lp is used for deflecting the light path;

a third lens L3 with negative dioptric power, the third lens L3 having an object-side S5 that is concave paraxially and circumferentially, and the third lens L3 having an image-side S6 that is concave paraxially and circumferentially;

a fifth lens element L5 with positive refractive power, the fifth lens element L5 having an object-side surface S9 that is convex paraxially and circumferentially, and the fifth lens element L5 having an image-side surface S10 that is concave paraxially and circumferentially;

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 in which data of focal length is obtained using light having a wavelength of 555nm, data of refractive index and dispersion coefficient is obtained using light having a wavelength of 587.56nm, and the units of radius of curvature and thickness are 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 × 2), HFOV, DL/TTL, TTL/f, EFY (L2 to L7), T56/T67, | f2/f1|, and | V2-V4| of the optical systems of the first to seventh embodiments.

TABLE 8

	TTL/(ImgH*2)	HFOV(°)	DL/TTL	TTL/f
					First embodiment	1.990456714	13.3	0.659246575	0.947283049
Second embodiment	2.010906612	13.3	0.674576271	0.962479608
					Third embodiment	2.060327198	13.1	0.675765095	0.971084337
Fourth embodiment	1.954669393	15.2	0.721011334	1.071962617
					Fifth embodiment	2.099522836	12.6	0.666396104	0.955779674
Sixth embodiment	2.109747785	12.6	0.684975767	0.961926962
					Seventh embodiment	1.862644853	15	0.719121683	1.002752294
	EFY(L2～L7)(mm)	T56/T67	\|f2/f1\|	\|V2-V4\|
					First embodiment	15.74	0.140785592	0.089818061	34.61
Second embodiment	15.52	0.18738194	0.085389998	34.61
					Third embodiment	15.14	0.186302972	0.078322455	34.61
Fourth embodiment	12.36	0.138018458	0.072255703	34.61
					Fifth embodiment	12.6	0.090736713	0.091149281	34.61
Sixth embodiment	16.47	0.089362322	0.09386172	34.61
					Seventh embodiment	13.08	0.099603401	0.097745095	34.61

As can be seen from table 8, each example satisfies the following conditional expression: 1.6< TTL/(ImgH x 2) <2.5, 11 ° < HFOV <16 °, 0.6< DL/TTL <0.8, 0.9< TTL/f <1.2, EFY (L2-L7) >10mm, T56/T67<0.25, | f2/f1| <0.3, | V2-V4| > 30.

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 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, in order from an object side to an image side along a first optical axis, comprising:

the first lens element with positive refractive power has a convex object-side surface and a flat image-side surface;

the prism is used for turning the light path so that the light path is turned to a second optical axis by the first optical axis, and the first optical axis is intersected with the second optical axis;

the object side to the image side along the second optical axis direction sequentially comprises:

the second lens element with positive refractive power has a convex object-side surface paraxial region and a convex image-side surface paraxial region;

the third lens element with refractive power has a concave object-side surface at the paraxial region;

a fourth lens element with refractive power;

a fifth lens element with refractive power;

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

the seventh lens element with negative refractive power.

2. The optical system according to claim 1, wherein at least one surface of at least one of the first lens to the seventh lens is an aspherical surface.

3. The optical system according to claim 1, wherein the optical system satisfies the conditional expression:

1.6<TTL/(ImgH*2)<2.5；

wherein, TTL is a distance from an object-side surface of the second lens element to an imaging surface of the optical system on the second optical axis, and ImgH is a half of a diagonal length of an effective imaging area of the optical system on the imaging surface.

4. The optical system according to claim 1, wherein the optical system satisfies the conditional expression:

11°<HFOV<16°；

wherein the HFOV is half of a maximum field angle of the optical system.

5. The optical system according to claim 1, wherein the optical system satisfies the conditional expression:

0.6<DL/TTL<0.8；

wherein, TTL is a distance between an object-side surface of the second lens element and an image plane of the optical system on the second optical axis, and DL is a distance between the object-side surface of the second lens element and an image-side surface of the seventh lens element on the second optical axis.

6. The optical system according to claim 1, wherein the optical system satisfies the conditional expression:

0.9<TTL/f<1.2；

wherein, TTL is a distance from an object-side surface of the second lens element to an image plane of the optical system on the second optical axis, and f is an effective focal length of the optical system.

7. The optical system according to claim 1, wherein the optical system satisfies the conditional expression:

EFY(L2～L7)>10mm；

and EFY (L2-L7) is the focal length of the rear lens group consisting of the second lens to the seventh lens.

8. The optical system according to claim 1, wherein the optical system satisfies the conditional expression:

T56/T67<0.25；

wherein T56 is a distance between an image-side surface of the fifth lens element and an object-side surface of the sixth lens element on the second optical axis, and T67 is a distance between an image-side surface of the sixth lens element and an object-side surface of the seventh lens element on the second optical axis.

9. The optical system according to claim 1, wherein the optical system satisfies the conditional expression:

|f2/f1|<0.3；

wherein f1 is the effective focal length of the first lens, and f2 is the effective focal length of the second lens.

10. The optical system according to claim 1, wherein the optical system satisfies the conditional expression:

|V2-V4|>30；

wherein V2 is the second lens Abbe number, and V4 is the fourth lens Abbe number.

11. A camera module, comprising a lens barrel, an electronic photosensitive element and the optical system according to any one of claims 1 to 8, wherein the first to seventh lenses and the prism 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 an optical signal of an object incident on the electronic photosensitive element through the first to seventh lenses into an electrical signal of an image.

12. An electronic device comprising a housing and the camera module of claim 9, wherein the camera module is disposed within the housing.