CN112198630A

CN112198630A - Optical system, lens module and electronic equipment

Info

Publication number: CN112198630A
Application number: CN202011153035.0A
Authority: CN
Inventors: 王妮妮; 刘彬彬; 李明; 邹海荣
Original assignee: Jiangxi Jingchao Optical Co Ltd
Current assignee: Jiangxi Jingchao Optical Co Ltd
Priority date: 2020-10-23
Filing date: 2020-10-23
Publication date: 2021-01-08

Abstract

The invention provides an optical system, a lens module and an electronic device. 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; a second lens element with refractive power; a third lens element with refractive power; a fourth lens element with refractive power; a fifth lens element with refractive power; a sixth lens element with positive refractive power; a seventh lens element with negative refractive power having a concave image-side surface at the paraxial region; the optical system satisfies the conditional expression: and 4, more than or equal to (Y72T L)/(ET 7F) less than or equal to 10, wherein Y72 is the maximum optical effective radius of the image side surface of the seventh lens, TL is the distance between the object side surface of the first lens and the imaging surface of the optical system on the optical axis, ET7 is the distance between the object side surface of the seventh lens and the image side surface of the seventh lens on the optical axis at the maximum optical effective radius, and f is the focal length of the optical system. The wide-angle shooting and miniaturization requirements can be met.

Description

Optical system, lens module and electronic equipment

Technical Field

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

Background

Nowadays, with the rapid development of science and technology, the imaging quality of mobile electronic products is more and more required by consumers. In order to meet the requirements of a high-order imaging system and realize a wide-angle shooting effect, the seven-piece lens can be used as one of the accessories of various types of camera-shooting portable electronic equipment. However, the conventional seven-piece lens cannot satisfy both the requirements of a large field angle and miniaturization.

Disclosure of Invention

An object of the present application is to provide an optical system, a lens module and an electronic device, which are used to solve 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: the first lens element with positive refractive power has a convex object-side surface at a paraxial region; a second lens element with refractive power; a third lens element with refractive power; a fourth lens element with refractive power; a fifth lens element with refractive power; a sixth lens element with positive refractive power; the seventh lens element with negative refractive power has a concave image-side surface at the paraxial region; the optical system satisfies the conditional expression: 4 ≦ (Y72 ANGSTROM)/(ET 7 ANGSTROM f) ≦ 10, wherein Y72 is the maximum optically effective radius of the image side surface of the seventh lens, TL is the distance on the optical axis from the object side surface of the first lens to the image plane of the optical system, ET7 is the distance on the optical axis from the object side surface of the seventh lens at the maximum optically effective radius to the image side surface of the seventh lens at the maximum optically effective radius, and f is the focal length of the optical system. By reasonably configuring the surface shapes and the refractive powers of the first lens element to the seventh lens element, the seven-piece optical system can meet the requirements of high pixel and good image quality. When the optical system satisfies the above conditional expression, the larger field angle of the optical system and the thickness of the optical system can be balanced, and the size of the optical system can be reduced while the forming yield of the seventh lens is ensured.

Wherein the optical system satisfies the conditional expression: TL/EPD is more than or equal to 2 and less than or equal to 3, wherein EPD is the entrance pupil diameter of the optical system. When the optical system satisfies the above conditional expressions, the total length of the optical system can be reduced and the amount of light entering can be increased.

Wherein the optical system satisfies the conditional expression: the effective diameter of the object side surface of the first lens is provided with a tangent plane at each place, the tangent plane intersects with a plane perpendicular to the optical axis to form an acute included angle, the maximum value of the acute included angle is AL1S1, the effective diameter of the object side surface of the second lens is provided with a tangent plane at each place, the tangent plane intersects with the plane perpendicular to the optical axis to form an acute included angle, and the maximum value of the acute included angle is AL1S 2. When the optical system satisfies the above conditional expressions, the first lens production sensitivity can be reduced, and a larger angle of view is realized.

Wherein the optical system satisfies the conditional expression: MVd/f is more than or equal to 10 and less than or equal to 20, wherein MVd is the average value of the Abbe numbers of the first lens to the seventh lens. When the optical system meets the conditional expression, the chromatic aberration can be balanced, the high Abbe number and the low Abbe number are matched to correspond to different refractive indexes, and a larger field angle and good optical imaging performance can be realized through different material combinations.

Wherein the optical system satisfies the conditional expression: ET1/(CT1 f) is more than or equal to 0 and less than or equal to 1mm^－1Wherein ET1 is a distance on an optical axis from an object-side surface of the first lens at the maximum optical effective diameter to an image-side surface of the first lens at the maximum optical effective diameter, and CT1 is a thickness of the first lens on the optical axis. When the optical system satisfies the above conditional expressions, the molding of the first lens can be facilitated.

Wherein the optical system satisfies the conditional expression: ET7/(CT7 f) is more than or equal to 0 and less than or equal to 1mm^－1Wherein CT7 is the thickness of the seventh lens element on the optical axis. When the optical system satisfies the above conditional expressions, the molding of the seventh lens can be facilitated.

Wherein the optical system satisfies the conditional expression: 0 < EPD/f < 1, wherein EPD is the entrance pupil diameter of the optical system. When the optical system satisfies the above conditional expression, the amount of light passing and the image plane retrogradation can be balanced, and a large aperture and a large field angle can be realized.

Wherein the optical system satisfies the conditional expression: 0 ≦ (MIN6 MAX7)/(MAX6 MIN7) ≦ 1, wherein MIN6 is a minimum thickness of the sixth lens in the optical axis direction within the maximum optical effective diameter, MAX6 is a maximum thickness of the sixth lens in the optical axis direction within the maximum optical effective diameter, MIN7 is a minimum thickness of the seventh lens in the optical axis direction within the maximum optical effective diameter, and MAX7 is a maximum thickness of the seventh lens in the optical axis direction within the maximum optical effective diameter. When the optical system satisfies the above conditional expression, the yield of injection molding can be improved, and the larger field angle and astigmatism can be balanced.

Wherein the optical system satisfies the conditional expression: 0 is less than or equal to (CT5+ CT7)/CT6 is less than or equal to 2, wherein CT5 is the thickness of the fifth lens on the optical axis, CT6 is the thickness of the sixth lens on the optical axis, and CT7 is the thickness of the seventh lens on the optical axis. When the optical system satisfies the above conditional expressions, it is advantageous to expand the angle of view and balance aberrations.

Wherein the optical system satisfies the conditional expression: TL/ImgH is more than or equal to 1 and less than or equal to 2, wherein ImgH is half of the image height corresponding to the maximum field angle of the optical system. When the optical system satisfies the above conditional expressions, it is advantageous to realize miniaturization of the optical system.

The invention provides a lens module, which comprises a lens barrel, an electronic photosensitive element and the optical system, wherein the optical system is arranged in the lens barrel, and the electronic photosensitive element is arranged on the image side of the optical system. The electronic photosensitive element is arranged on the image side of the optical system and used for converting light rays of an object which passes through the first lens to the seventh lens and is incident on the electronic photosensitive element into an electric signal of an image. By installing the first lens element to the seventh lens element of the optical system in the lens module, the surface shapes and refractive powers of the first lens element to the seventh lens element are reasonably configured, so that the seven-piece optical system can simultaneously meet the requirements of a larger field angle and miniaturization.

The invention provides electronic equipment which comprises a shell and the lens module, wherein the lens module is arranged in the shell. This application can make electronic equipment satisfy great angle of vision and miniaturized requirement simultaneously through set up above-mentioned lens module in electronic equipment.

To sum up, the optical system of seven formula lenses of this application to compact space arrangement has not only realized wide angle and has made a video recording, and optical system is frivolous moreover, and the overall length is shorter to according to rational distribution refractive power, balanced whole optical system's aberration, reduced optical system's sensitivity, can carry out batch production processing, satisfied current market demand.

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 lens 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 to a 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. The electron sensor may be a Complementary Metal Oxide Semiconductor (CMOS) or a Charge-coupled Device (CCD). The lens module can be an independent lens of a digital camera, and can also be an imaging module integrated on electronic equipment such as a smart phone. By installing the first lens element to the seventh lens element of the optical system in the lens module and reasonably configuring the surface shapes and refractive powers of the first lens element to the seventh lens element, the optical system of the seven-piece lens element can simultaneously meet the requirements of a larger field angle and miniaturization.

The embodiment of the application provides electronic equipment, and the electronic equipment comprises a shell and a lens module provided by the embodiment of the application. The lens 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. The lens module is arranged in the electronic equipment, so that the electronic equipment can meet the requirements of a large field angle and miniaturization.

The present disclosure provides an optical system including, in order from an object side to an image side in an optical axis direction, a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element, a sixth lens element, and a seventh lens element. 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 at a paraxial region; a second lens element with refractive power; a third lens element with refractive power; a fourth lens element with refractive power; a fifth lens element with refractive power; a sixth lens element with positive refractive power; the seventh lens element with negative refractive power has a concave image-side surface at the paraxial region; the optical system satisfies the conditional expression: 4 ≦ (Y72 ANGSTROM)/(ET 7 ANGSTROM f) ≦ 10, wherein Y72 is the maximum optically effective radius of the image side surface of the seventh lens, TL is the distance on the optical axis from the object side surface of the first lens to the image plane of the optical system, ET7 is the distance on the optical axis from the object side surface of the seventh lens at the maximum optically effective radius to the image side surface of the seventh lens at the maximum optically effective radius, and f is the focal length of the optical system. By reasonably configuring the surface shapes and the refractive powers of the first lens element to the seventh lens element, the seven-piece optical system can meet the requirements of high pixel and good image quality. When the optical system satisfies the above conditional expression, the larger field angle of the optical system and the thickness of the optical system can be balanced, and the size of the optical system can be reduced while the forming yield of the seventh lens is ensured.

In a specific embodiment, the optical system satisfies the conditional expression: TL/EPD is more than or equal to 2 and less than or equal to 3, wherein EPD is the entrance pupil diameter of the optical system. Optionally, the optical system satisfies the conditional expression: TL/EPD is more than or equal to 2.143 and less than or equal to 2.924. When the optical system satisfies the above conditional expressions, the total length of the optical system can be reduced and the amount of light entering can be increased.

In a specific embodiment, the optical system satisfies the conditional expression: the effective diameter of the object side surface of the first lens is provided with a tangent plane at each place, the tangent plane intersects with a plane perpendicular to the optical axis to form an acute included angle, the maximum value of the acute included angle is AL1S1, the effective diameter of the object side surface of the second lens is provided with a tangent plane at each place, the tangent plane intersects with the plane perpendicular to the optical axis to form an acute included angle, and the maximum value of the acute included angle is AL1S 2. Optionally, the optical system satisfies the conditional expression: 9.754 is less than or equal to (| AL1S1| + | AL2S1|)/f is less than or equal to 18.909. When the optical system satisfies the above conditional expressions, the first lens production sensitivity can be reduced, and a larger angle of view is realized.

In a specific embodiment, the optical system satisfies the conditional expression: MVd/f is more than or equal to 10 and less than or equal to 20, wherein MVd is the average value of the Abbe numbers of the first lens to the seventh lens. Optionally, the optical system satisfies the conditional expression: the MVd/f is not less than 12.114 and not more than 16.05. When the optical system meets the conditional expression, the chromatic aberration can be balanced, the high Abbe number and the low Abbe number are matched to correspond to different refractive indexes, and a larger field angle and good optical imaging performance can be realized through different material combinations.

The optical system satisfies the conditional expression: ET1/(CT1 f) is more than or equal to 0 and less than or equal to 1mm^－1Wherein ET1 is a distance on an optical axis from an object-side surface of the first lens at the maximum optical effective diameter to an image-side surface of the first lens at the maximum optical effective diameter, and CT1 is a thickness of the first lens on the optical axis. Optionally, the optical system satisfies the conditional expression: 0.132mm^－1≤ET1/(CT1＊f)≤0.211mm^－1. When the optical system satisfies the above conditional expressions, the molding of the first lens can be facilitated.

In a specific embodiment, the optical system satisfies the conditional expression: ET7/(CT7 f) is more than or equal to 0 and less than or equal to 1mm^－1Wherein CT7 is the thickness of the seventh lens element on the optical axis. Optionally, the optical system satisfies the conditional expression: 0.324mm^－1≤ET7/(CT7＊f)≤0.528mm^－1. When the optical system satisfies the above conditional expressions, the molding of the seventh lens can be facilitated.

In a specific embodiment, the optical system satisfies the conditional expression: 0 < EPD/f < 1, wherein EPD is the entrance pupil diameter of the optical system. Optionally, the optical system satisfies the conditional expression: 0.495 is less than or equal to EPD/f is less than or equal to 0.633. When the optical system satisfies the above conditional expression, the amount of light passing and the image plane retrogradation can be balanced, and a large aperture and a large field angle can be realized.

In a specific embodiment, the optical system satisfies the conditional expression: 0 ≦ (MIN6 MAX7)/(MAX6 MIN7) ≦ 1, wherein MIN6 is a minimum thickness of the sixth lens in the optical axis direction within the maximum optical effective diameter, MAX6 is a maximum thickness of the sixth lens in the optical axis direction within the maximum optical effective diameter, MIN7 is a minimum thickness of the seventh lens in the optical axis direction within the maximum optical effective diameter, and MAX7 is a maximum thickness of the seventh lens in the optical axis direction within the maximum optical effective diameter. Optionally, the optical system satisfies the conditional expression: 0.15-0.364 (MIN6 MAX7)/(MAX6 MIN 7). When the optical system satisfies the above conditional expression, the yield of injection molding can be improved, and the larger field angle and astigmatism can be balanced.

In a specific embodiment, the optical system satisfies the conditional expression: 0 is less than or equal to (CT5+ CT7)/CT6 is less than or equal to 2, wherein CT5 is the thickness of the fifth lens on the optical axis, CT6 is the thickness of the sixth lens on the optical axis, and CT7 is the thickness of the seventh lens on the optical axis. Optionally, the optical system satisfies the conditional expression: 0.903 ≦ (CT5+ CT7)/CT6 ≦ 1.812. When the optical system satisfies the above conditional expressions, it is advantageous to expand the angle of view and balance aberrations.

In a specific embodiment, the optical system satisfies the conditional expression: TL/ImgH is more than or equal to 1 and less than or equal to 2, wherein ImgH is half of the image height corresponding to the maximum field angle of the optical system. Optionally, the optical system satisfies the conditional expression: TL/ImgH is more than or equal to 1.324 and less than or equal to 1.734. When the optical system satisfies the above conditional expressions, it is advantageous to realize miniaturization of the optical system.

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

A fourth lens element L4 with positive refractive power having a convex 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 L4 is convex at the circumference, and the image-side surface S8 is convex at the circumference.

The fifth lens element L5 with negative 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 concave at paraxial region; the object-side surface S9 of the fifth lens element L5 is concave at the circumference, and the image-side surface S10 is convex at the circumference.

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

The seventh lens element L7 with negative refractive power has an object-side surface S11 of the seventh lens element L7 being concave at paraxial region and an image-side surface S12 being concave at paraxial region; the object-side surface S11 of the seventh lens element L7 is convex at the circumference, and the image-side surface S12 is convex at the circumference.

The first lens element L1 to the seventh lens element L7 are all made of plastic.

Further, the optical system includes a stop STO, an infrared filter L8, and an image plane S17. 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 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 380 nm-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.

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 the focal length of the optical system, FNO is the f-number of the optical system, and FOV is the angle of view of the optical system.

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 a 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. 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 the longitudinal spherical aberration diagram of FIG. 1b, the longitudinal spherical aberration generated by the optical system for the light with wavelengths of 470.0000nm, 510.0000nm, 587.5618nm, 610.0000nm and 650.0000nm is between-0.025 mm and 0.01 mm; as can be seen from the astigmatism diagram of FIG. 1b, the astigmatism of the optical system for a light ray with a wavelength of 587.5618nm in the tangential direction and the sagittal direction is between-0.03 mm and 0.03 mm; according to the distortion diagram of FIG. 1b, the distortion of the optical system to 587.5618nm light is between 0.0% and 2.0%. As can be seen from fig. 1b, 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. 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 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 convex 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 concave at the circumference, and the image-side surface S4 is convex 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 convex at paraxial region and an image-side surface S6 being concave at paraxial region; the object-side surface S5 of the third lens element L3 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 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.

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 concave at paraxial region; the object-side surface S9 of the fifth lens element L5 is concave at the circumference, and the image-side surface S10 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 the longitudinal spherical aberration diagram of FIG. 2b, the longitudinal spherical aberration of the optical system generated by the light with wavelengths of 470.0000nm, 510.0000nm, 587.5618nm, 610.0000nm and 650.0000nm is between-0.075 mm and 0.03 mm; referring to FIG. 2b, the astigmatism of the optical system for a ray with a wavelength of 587.5618nm in the tangential direction and the sagittal direction is between-0.01 mm and 0.04 mm; from the distortion diagram of fig. 2b, the distortion of the optical system to 587.5618nm light is between 0.0% and 2.0%. As can be seen from fig. 2b, 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 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 negative 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 concave at paraxial region; the object-side surface S5 of the third lens element L3 is concave at the circumference, and the image-side surface S6 is convex at the circumference.

The fourth lens element L4 with positive refractive power has an object-side surface S7 of the fourth lens element L4 being convex at paraxial region and an image-side surface S8 being convex 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.

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

The seventh lens element L7 with negative refractive power has an object-side surface S11 of the seventh lens element L7 being concave at paraxial region and an image-side surface S12 being concave at paraxial region; the object-side surface S11 of the seventh lens element L7 is concave at the circumference, and the image-side surface S12 is convex 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 shown in the diagram of FIG. 3b, the longitudinal spherical aberration generated by the optical system for the light with wavelengths of 470.0000nm, 510.0000nm, 587.5618nm, 610.0000nm and 650.0000nm is between-0.02 mm and 0.02 mm; as can be seen from the astigmatism diagram of FIG. 3b, the astigmatism of the optical system for a light ray with a wavelength of 587.5618nm in the tangential direction and the sagittal direction is between-0.02 mm and 0.02 mm; according to the distortion diagram of FIG. 3b, the distortion of the optical system to 587.5618nm light is between 0.0% and 2.0%. As can be seen from fig. 3b, 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 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:

A second lens element L2 with positive 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 negative 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 concave at the circumference, and the image-side surface S6 is convex at the circumference.

The fourth lens element L4 with positive refractive power has an object-side surface S7 of the fourth lens element L4 being convex at paraxial region and an image-side surface S8 being convex at paraxial region; the object-side surface S7 of the fourth lens element L4 is convex at the circumference, and the image-side surface S8 is convex at the circumference.

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

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 shown in the diagram of FIG. 4b, the longitudinal spherical aberration generated by the optical system for the light with wavelengths of 470.0000nm, 510.0000nm, 587.5618nm, 610.0000nm and 650.0000nm is between-0.06 mm and 0.02 mm; from the astigmatism diagram of fig. 4b, the astigmatism of the optical system for a light ray with a wavelength of 587.5618nm in the tangential direction and the sagittal direction is between-0.02 mm and 0.02 mm; from the distortion diagram of FIG. 4b, the distortion of the optical system to 587.5618nm light is between 0.0% and 2.0%. As can be seen from fig. 4b, the optical system according to the fourth embodiment can achieve good imaging quality.

In the fifth embodiment, the first 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 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.

A second lens element L2 with negative refractive power having an object-side surface S3 of the second lens element L2 being concave 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 concave at the circumference, and the image-side surface S4 is convex 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 convex at paraxial region and an image-side surface S6 being concave 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 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 concave 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 positive refractive power has an object-side surface S11 of the sixth lens element L6 being convex at paraxial region and an image-side surface S11 being concave at paraxial region; the object-side surface S11 of the sixth lens element L6 is concave at the circumference, and the image-side surface S12 is convex at the circumference.

The seventh lens element L7 with negative refractive power has an object-side surface S11 of the seventh lens element L7 being convex at paraxial region and an image-side surface S12 being concave at paraxial region; the object-side surface S11 of the seventh lens element L7 is convex 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 the longitudinal spherical aberration diagram of FIG. 5b, the longitudinal spherical aberration generated by the optical system for the light with wavelengths of 470.0000nm, 510.0000nm, 587.5618nm, 610.0000nm and 650.0000nm is between-0.025 mm and 0.02 mm; as can be seen from the astigmatism diagram of FIG. 5b, the astigmatism of the optical system for a light ray with a wavelength of 587.5618nm in the tangential direction and the sagittal direction is between-0.01 mm and 0.03 mm; according to the distortion diagram of FIG. 5b, the distortion of the optical system to 587.5618nm light is between 0.0% and 2.0%. As can be seen from fig. 5b, the optical system according to the fifth embodiment can achieve good image quality.

In a sixth embodiment of the present invention,

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 third lens element L3 with negative 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 concave 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.

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

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

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 shown in the diagram of FIG. 6b, the longitudinal spherical aberration generated by the optical system for the light with wavelengths of 470.0000nm, 510.0000nm, 587.5618nm, 610.0000nm and 650.0000nm is between-0.01 mm and 0.01 mm; referring to FIG. 6b, the astigmatism of the optical system for a ray with a wavelength of 587.5618nm in the tangential and sagittal directions is between-0.06 mm and 0.01 mm; from the distortion diagram of FIG. 6b, the distortion of the optical system to 587.5618nm light is between 0.0% and 2.0%. 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:

A second lens element L2 with negative refractive power having a concave object-side surface S3 and a convex image-side surface S4 at paraxial region, respectively, of the second lens element L2; the object-side surface S3 of the second lens element L2 is concave at the circumference, and the image-side surface S4 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 convex at paraxial region and an image-side surface S2 being concave 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.

A fourth lens element L4 with positive refractive power having a concave object-side surface S7 and a convex 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 convex 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 concave at the circumference, and the image-side surface S10 is convex at the circumference.

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 shown in the diagram of FIG. 7b, the longitudinal spherical aberration generated by the optical system for the light with wavelengths of 470.0000nm, 510.0000nm, 587.5618nm, 610.0000nm and 650.0000nm is between-0.04 mm and 0.02 mm; referring to FIG. 7b, the astigmatism of the optical system for a ray with a wavelength of 587.5618nm in the tangential and sagittal directions is between-0.01 mm and 0.03 mm; according to the distortion diagram of FIG. 7b, the distortion of the optical system to 587.5618nm light is between 0.0% and 2.0%. 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 (Y72 ANG TL)/(ET7 ANG F), TL/EPD, (| AL1S1| + | AL2S1|)/f, MVd/f, ET1/(CT1 ANG f), ET7/(CT7 ANG f), EPD/f, (MIN6 MAX7)/(MAX6 ANG MIN7), (CT5+ CT7)/CT6, TL/ImgH of the optical systems of the first to seventh embodiments.

TABLE 8

	(Y72＊TL)/(ET7＊f)	TL/EPD	(\|AL1S1\|+\|AL2S1\|)/f	MVd/f	ET1/(CT1＊f)
						First embodiment	7.437	2.746	9.754	13.991	0.188
Second embodiment	9.036	2.742	18.909	12.606	0.184
						Third embodiment	4.984	2.143	18.205	13.462	0.132
Fourth embodiment	7.328	2.244	13.359	13.037	0.143
						Fifth embodiment	6.711	2.924	12.886	12.114	0.153
Sixth embodiment	6.741	2.725	15.671	16.05	0.211
						Seventh embodiment	6.753	2.876	10.886	12.532	0.152
	ET7/(CT7＊f)	EPD/f	(MIN6＊MAX7)/(MAX6＊MIN7)	(CT5+CT7)/CT6	TL/ImgH
						First embodiment	0.470	0.505	0.204	0.903	1.36
Second embodiment	0.374	0.495	0.207	1.323	1.324
						Third embodiment	0.528	0.633	0.261	1.068	1.581
Fourth embodiment	0.416	0.606	0.223	1.092	1.475
						Fifth embodiment	0.324	0.513	0.364	1.812	1.734
Sixth embodiment	0.495	0.5	0.15	0.925	1.491
						Seventh embodiment	0.457	0.526	0.254	1.384	1.692

As is apparent from Table 8, each example satisfies the following conditional expressions of 4. ltoreq. Y72 ANG TL)/(ET7 ANG F. ltoreq.10, 2. ltoreq. TL/EPD. ltoreq.3, 9. ltoreq. AL1S1| + | AL2S1 |)/f. ltoreq.20, 10. ltoreq. MVd/f. ltoreq.20, 0. ltoreq. ET1/(CT1 ANG F.) ltoreq.1 mm^－1、0≤ET7/(CT7＊f)≤1mm^－1、0≤EPD/f≤1、0≤(MIN6＊MAX7)/(MAX6＊MIN7)≤1、0≤(CT5+CT7)/CT6≤2、1≤TL/ImgH≤2。

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, however, as long as there is no contradiction between the combinations of the technical features, the scope of the present description should be considered.

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 in an optical axis direction:

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

a second lens element with refractive power;

a third lens element with refractive power;

a fourth lens element with refractive power;

a fifth lens element with refractive power;

a sixth lens element with positive refractive power;

the seventh lens element with negative refractive power has a concave image-side surface at the paraxial region;

the optical system satisfies the conditional expression: 4 ≦ (Y72 ANGSTROM)/(ET 7 ANGSTROM f) ≦ 10, wherein Y72 is the maximum optically effective radius of the image side surface of the seventh lens, TL is the distance on the optical axis from the object side surface of the first lens to the image plane of the optical system, ET7 is the distance on the optical axis from the object side surface of the seventh lens at the maximum optically effective radius to the image side surface of the seventh lens at the maximum optically effective radius, and f is the focal length of the optical system.

2. The optical system according to claim 1, wherein the optical system satisfies the conditional expression: TL/EPD is more than or equal to 2 and less than or equal to 3, wherein EPD is the entrance pupil diameter of the optical system.

3. The optical system according to claim 1, wherein the optical system satisfies the conditional expression: the effective diameter of the object side surface of the first lens is provided with a tangent plane at each place, the tangent plane intersects with a plane perpendicular to the optical axis to form an acute included angle, the maximum value of the acute included angle is AL1S1, the effective diameter of the object side surface of the second lens is provided with a tangent plane at each place, the tangent plane intersects with the plane perpendicular to the optical axis to form an acute included angle, and the maximum value of the acute included angle is AL1S 2.

4. The optical system according to claim 1, wherein the optical system satisfies the conditional expression: MVd/f is more than or equal to 10 and less than or equal to 20, wherein MVd is the average value of the Abbe numbers of the first lens to the seventh lens.

5. The optical system according to claim 1, wherein the optical system satisfies the conditional expression: ET1/(CT1 f) is more than or equal to 0 and less than or equal to 1mm^－1Wherein ET1 is a distance on an optical axis from an object-side surface of the first lens at the maximum optical effective diameter to an image-side surface of the first lens at the maximum optical effective diameter, and CT1 is a thickness of the first lens on the optical axis.

6. The optical system according to claim 1, wherein the optical system satisfies the conditional expression: ET7/(CT7 f) is more than or equal to 0 and less than or equal to 1mm^－1Wherein CT7 is the thickness of the seventh lens element on the optical axis.

7. The optical system according to claim 1, wherein the optical system satisfies the conditional expression: 0 < EPD/f < 1, wherein EPD is the entrance pupil diameter of the optical system.

8. The optical system according to claim 1, wherein the optical system satisfies the conditional expression: 0 ≦ (MIN6 MAX7)/(MAX6 MIN7) ≦ 1, wherein MIN6 is a minimum thickness of the sixth lens in the optical axis direction within the maximum optical effective diameter, MAX6 is a maximum thickness of the sixth lens in the optical axis direction within the maximum optical effective diameter, MIN7 is a minimum thickness of the seventh lens in the optical axis direction within the maximum optical effective diameter, and MAX7 is a maximum thickness of the seventh lens in the optical axis direction within the maximum optical effective diameter.

9. The optical system according to claim 1, wherein the optical system satisfies the conditional expression: 0 is less than or equal to (CT5+ CT7)/CT6 is less than or equal to 2, wherein CT5 is the thickness of the fifth lens on the optical axis, CT6 is the thickness of the sixth lens on the optical axis, and CT7 is the thickness of the seventh lens on the optical axis.

10. The optical system according to claim 1, wherein the optical system satisfies the conditional expression: TL/ImgH is more than or equal to 1 and less than or equal to 2, wherein ImgH is half of the image height corresponding to the maximum field angle of the optical system.

11. A lens module comprising a lens barrel, an electro-optic device and the optical system of any one of claims 1 to 10, wherein the optical system is disposed in the lens barrel, and the electro-optic device is disposed on an image side of the optical system.

12. An electronic device comprising a housing and the lens module as recited in claim 11, wherein the lens module is disposed in the housing.