CN112154363A

CN112154363A - Optical imaging system and electronic device

Info

Publication number: CN112154363A
Application number: CN201980031220.1A
Authority: CN
Inventors: 毛庆
Original assignee: SZ DJI Technology Co Ltd
Current assignee: Shenzhen Zhuoyu Technology Co ltd
Priority date: 2019-07-10
Filing date: 2019-07-10
Publication date: 2020-12-29
Anticipated expiration: 2039-07-10
Also published as: WO2021003720A1; CN112154363B

Abstract

An optical imaging system and an electronic device, the optical imaging system (100) comprising, in order from an object side to an image side: a first lens element (101) with negative refractive power having a convex object-side surface and a concave image-side surface; a second lens element (102) with positive refractive power having a convex object-side surface and a concave image-side surface; a third lens element (103) with positive refractive power having a convex object-side surface; a fourth lens element (104) with positive refractive power having a convex object-side surface and a convex image-side surface; a fifth lens element (105) with positive refractive power having a concave object-side surface and a convex image-side surface; a sixth lens element (106) with positive refractive power having a convex image-side surface; the seventh lens element (107) with negative refractive power has a concave image-side surface. The optical imaging system and the electronic device have high miniaturization degree, light whole weight and better imaging quality.

Description

Optical imaging system and electronic device

Technical Field

The present invention generally relates to the field of optical imaging, and more particularly to an optical imaging system and an electronic device.

Background

In recent years, with the development of science and technology, portable electronic products have been gradually raised, which simultaneously promotes the development of camera products applied to portable electronic devices, and camera wide-angle lens products with miniaturized high pixel and large aperture are favored by more people.

With the development of electronic products, the market demand for large-sized CMOS configured electronic products is higher and higher. With the increase of the size of the CMOS, the depth of field becomes shallower under the same aperture, and the requirements of different environments and different scenes cannot be met.

In addition, the current market meets the requirement of one-inch CMOS and above lenses, and most of the lenses adopt all-glass lenses, so that the miniaturization degree is low, and the whole weight is heavy.

Therefore, in view of the above technical problems, it is necessary to provide a new optical imaging system and an electronic device.

Disclosure of Invention

In this summary, concepts in a simplified form are introduced that are further described in the detailed description. This summary of the invention is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

In view of the deficiencies of the prior art, the present invention provides an optical imaging system, in order from an object side to an image side, comprising:

the lens comprises a first lens element with negative refractive power having a convex object-side surface and a concave image-side surface;

a second lens element with positive refractive power having a convex object-side surface and a concave image-side surface;

a third lens element with positive refractive power having a convex object-side surface;

a fourth lens element with positive refractive power having a convex object-side surface and a convex image-side surface;

a fifth lens element with positive refractive power having a concave object-side surface and a convex image-side surface;

a sixth lens element with positive refractive power having a convex image-side surface;

the seventh lens element with negative refractive power has a concave image-side surface.

Another aspect of the present invention provides an electronic device including the above optical imaging system, and a photosensitive element disposed on an image side of the optical imaging system.

The optical imaging system and the electronic device have the advantages of high miniaturization degree, light overall weight and better imaging quality.

Drawings

The following drawings of the invention are included to provide a further understanding of the invention. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

In the drawings:

FIG. 1 shows a schematic diagram of an optical imaging system according to one embodiment of the invention;

FIG. 2 shows a positional chromatic aberration profile of an optical imaging system according to one embodiment of the invention;

FIG. 3 shows a chromatic aberration of magnification distribution diagram of an optical imaging system according to an embodiment of the invention;

fig. 4A, 4B show field curvature and distortion maps of an optical imaging system according to an embodiment of the present invention.

Detailed Description

In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the present invention. It will be apparent, however, to one skilled in the art, that the present invention may be practiced without one or more of these specific details. In other instances, well-known features have not been described in order to avoid obscuring the invention.

It is to be understood that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

For a better understanding of the present application, various aspects of the present application will be described in more detail with reference to the accompanying drawings. It should be understood that the detailed description is merely illustrative of exemplary embodiments of the present application and does not limit the scope of the present application in any way. Like reference numerals refer to like elements throughout the specification. The expression "and/or" includes any and all combinations of one or more of the associated listed items.

It should be noted that in this specification, the expressions first, second, third, etc. are used only to distinguish one feature from another, and do not represent any limitation on the features. For example, the first lens discussed below may also be referred to as the second lens or the third lens without departing from the teachings of the present application.

In the drawings, the thickness, size, and shape of the lens have been slightly exaggerated for convenience of explanation. In particular, the shapes of the spherical or aspherical surfaces shown in the drawings are shown by way of example. That is, the shape of the spherical surface or the aspherical surface is not limited to the shape of the spherical surface or the aspherical surface shown in the drawings. The figures are purely diagrammatic and not drawn to scale.

Herein, the paraxial region refers to a region near the optical axis. If the lens surface is convex and the convex position is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the concave position is not defined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the subject is referred to as the object-side surface of the lens, and the surface of each lens closest to the image plane is referred to as the image-side surface of the lens.

It will be further understood that the terms "comprises," "comprising," "has," "having," "includes" and/or "including," when used in this specification, specify the presence of stated features, elements, and/or components, but do not preclude the presence or addition of one or more other features, elements, components, and/or groups thereof. Moreover, when a statement such as "at least one of" appears after a list of listed features, the entirety of the listed features is modified rather than modifying individual elements in the list. Furthermore, when describing embodiments of the present application, the use of "may" mean "one or more embodiments of the present application. Also, the term "exemplary" is intended to refer to an example or illustration.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict.

At present, lenses which are matched with a photosensitive element of 1 inch or more and a large aperture on the market are mainly concentrated on digital lenses, and all the lenses are designed by adopting full glass, so that the weight is large, the miniaturization degree is low, and the product is difficult to carry. In order to meet the requirement of miniaturization, the maximum F number (the focal length of the lens/the diameter of the effective aperture of the lens) of the conventional lens is usually 2.8 or more than 2.8, and the whole captured picture is not ideal in the case of insufficient ambient light (such as overcast and rainy days, dusk, and the like). In addition, most of the adaptive photosensitive elements of the miniaturized lenses on the market are below 1/1.7, the aperture is constant, and the requirements of more professional users cannot be met.

In view of the above problems, the present invention provides an optical imaging system which is highly miniaturized, has a light weight, and has a good imaging quality.

An optical imaging system according to an embodiment of the present invention will be described in detail with reference to fig. 1 to 4B. In the description below, the lens has positive refractive power, indicating that it is convergent in refraction of light; the lens has negative refractive power, indicating that its refraction of light is divergent. The object side surface of the lens is convex, namely that any point on the object side surface of the lens is taken as a tangent plane, the surface is always positioned at the right side of the tangent plane, the curvature radius is positive, otherwise, the object side surface is concave, and the curvature radius is negative; if the lens surface is convex and the convex position is not defined, it means that the lens surface can be convex at the paraxial region; if the lens surface is concave and the concave locations are not defined, this means that the lens surface can be concave at the paraxial region. If the refractive power or focal length of the lens element does not define the position of the region, it means that the refractive power or focal length of the lens element can be the refractive power or focal length of the lens element at the paraxial region.

As shown in fig. 1, an optical imaging system 100 according to an embodiment of the present invention includes seven lenses, namely, a first lens 101, a second lens 102, a third lens 103, a fourth lens 104, a fifth lens 105, a sixth lens 106 and a seventh lens 107 arranged from an object side to an image side, wherein any two adjacent lenses have a space therebetween. Light rays from the side of the object sequentially pass through the first lens 101, the second lens 102, the third lens 103, the fourth lens 104, the fifth lens 105, the sixth lens 106 and the seventh lens 107, and then are imaged on an imaging surface on the image side of the seventh lens 107.

The first lens element 101 with negative refractive power has a convex object-side surface and a concave image-side surface; the second lens element 102 with positive refractive power has a convex object-side surface and a concave image-side surface; the third lens element 103 with positive refractive power has a convex object-side surface; the fourth lens element 104 with positive refractive power has a convex object-side surface and a convex image-side surface; the fifth lens element 105 with positive refractive power has a concave object-side surface and a convex image-side surface; the sixth lens element 106 with positive refractive power has a convex image-side surface; the seventh lens element 107 with negative refractive power has a concave image-side surface. The embodiment of the invention reasonably sets the seven lenses, so that the optical imaging system 100 has the advantages of small distortion and high pixel, and can meet the requirement of miniaturization.

In one embodiment, the seven lenses are plastic lenses. The optical imaging system 100 of the embodiment of the invention adopts the design scheme of the all-plastic lens, which is beneficial to reducing the weight of the optical imaging system, the miniaturization of equipment and the reduction of the production cost, and the plastic lens has lighter weight and smaller power consumption required by focusing, thereby reducing the heating of the equipment.

The optical imaging system of the present embodiment satisfies 0.4< f/TTL < 1.0. Wherein f is an effective focal length of the optical imaging system, and TTL is a distance on the optical axis from the object-side surface of the first lens element 101 to the image plane. Satisfying the above conditions is advantageous for maintaining high image quality while effectively shortening the system length.

The first lens element 101 with negative refractive power can provide a larger viewing angle; the object side surface is convex, so that the incident angle of peripheral light rays on the first lens element 101 can be reduced, the reduction of surface reflection is facilitated, and the optical imaging system is more suitable for wide-angle design.

In one embodiment, the first lens 101 satisfies the following condition: 0.25< | (R11-R12)/(R11+ R12) | <0.5, where R11 is the radius of curvature of the object-side surface of the first lens 101 and R12 is the radius of curvature of the image-side surface of the first lens 101. The optical imaging system has better flat field curvature capability while ensuring better distortion elimination capability by meeting the conditions.

The second lens element 102 with positive refractive power is used for converging light rays emitted from the first lens element 101, and can balance aberration generated by the first lens element 101. The object-side surface of the second lens element 102 is convex and the image-side surface is concave, and in one embodiment, the image-side surface of the first lens element 101 and the object-side surface of the second lens element 102 have substantially the same radius of curvature, so that the sensitivity of the lens optics can be reduced, the aberrations can be further suppressed, and the assembly of the lens optics is facilitated.

Further, the first lens 101 and the second lens 102 satisfy the following condition: 0< | (R12-R21)/(R21+ R12) | <0.3, where R21 is the radius of curvature of the object-side surface of the second lens 102 and R12 is the radius of curvature of the image-side surface of the first lens 101. By making the curvature radius of the object-side surface of the second lens element 102 and the curvature radius of the image-side surface of the first lens element 101 satisfy the above relationship, the second lens element 102 and the first lens element 101 can be better matched, which is advantageous for suppressing aberration, reducing the sensitivity of the lens element, and facilitating lens assembly. The outgoing light beam from the second lens 102 can be made incident on the sensor in a predetermined angle range by the cooperative action of the third lens 103 to the seventh lens 107.

The third lens element 103 with positive refractive power can buffer the light exiting from the second lens element 102. In one embodiment, the third lens 103 satisfies the following condition: f3/f is more than or equal to 3.0 and less than or equal to 5.0, wherein f is the effective focal length of the optical imaging system 100, and f3 is the effective focal length of the third lens 103. Therefore, the magnitude of the refractive power can be balanced, and the total length of the optical imaging system can be further controlled.

The fourth lens 104 is an aspheric lens, which can effectively improve off-axis aberration, and is beneficial to correcting the angle of emergent rays of the lens, thereby being capable of better matching with photosensitive elements. Further, the fourth lens 104 also satisfies the following condition: 1.5< nd ≦ 1.8, where nd is the refractive index of the fourth lens 104. Satisfying the above conditions is advantageous for reducing aberrations. And because the miniaturization requirement of the lens is met, the total length requirement of the lens is very short, so that the fourth lens 104 with the high refractive index is beneficial to quickly changing the light Ray direction, and the purpose of matching with the main light Angle (CRA, Chief Ray Angle) defined by the photosensitive element is achieved.

The fifth lens element 105 has positive refractive power, and satisfies the following condition: 0.15 & lt, CT5 & lt, 0.35, where CT5 is the center thickness of the fifth lens 105. Satisfying the above conditions is beneficial to the lens forming process, especially the plastic lens forming and homogeneity, and the system has good imaging quality. Further, the occurrence of the ghost phenomenon can be avoided by setting the thickness of the fifth lens 105 within the above range.

The sixth lens 106 satisfies the following condition: 0 ≦ CT6/ET6 ≦ 3.0, where CT6 is the center thickness of the sixth lens 106 and ET6 is the edge thickness of the sixth lens 106. The distance between the sixth lens element 106 and the seventh lens element 107 further satisfies 0< L67/TTL <0.1, where TTL is the on-axis distance from the object-side surface of the first lens element 101 to the image plane, and L67 is the on-axis distance from the image-side surface of the sixth lens element 106 to the object-side surface of the seventh lens element 107. Satisfying this requirement is advantageous for reducing the reflection between the sixth lens element 106 and the seventh lens element 107, and also for correcting the angle of the outgoing light of the optical imaging system, which can better match the photosensitive elements.

The seventh lens element 107 has negative refractive power. In addition, the object-side surface and the image-side surface of the seventh lens element 107 both have at least one inflection point, so that the angle of the light rays of the off-axis field incident on the photosensitive element can be effectively suppressed, and the off-axis aberration can be corrected to improve the peripheral imaging quality. The image side surface of the seventh lens element 107 changes from concave to convex from paraxial to peripheral, which is advantageous for reducing total reflection of light. Further, the object-side surface of the seventh lens element 107 is concave, and the shape thereof is matched with the image-side surface of the sixth lens element 106.

Further, the seventh lens 107 satisfies the following condition: where f is an effective focal length of the optical imaging system and f7 is an effective focal length of the seventh lens 107, | f7| < f where this condition is satisfied is advantageous for miniaturization of the optical imaging system.

The optical imaging system of the embodiment of the invention can be provided with at least one diaphragm to reduce stray light and improve image quality. The diaphragm may be an iris diaphragm, but is not limited to an iris diaphragm, and may be a non-iris diaphragm. In the optical imaging system of the embodiment of the present invention, the aperture configuration may be a front or a middle. The more forward the stop is located, the more beneficial the correction of CRA (i.e. the maximum angle of incidence of the chief ray on the electro-photosensitive element), and the more backward the stop is located, the larger FOV (maximum field angle) of the system is beneficial to satisfy the wide-angle characteristic of the optical imaging system, and in order to achieve a better balance between them, in a preferred embodiment, the stop is disposed in front of the object-side surface of the third lens 103. Further, the diaphragm can be arranged in front of the object side surface of the first lens 101, so that the number of lens barrels is reduced, and the cost is reduced.

In one embodiment, a filter element is also disposed between the seventh lens 107 and the imaging surface. The filtering element comprises an infrared filter used for filtering infrared band light entering the optical lens group and avoiding the infrared light from irradiating the photosensitive chip to generate noise. The material of the filter element comprises glass, and the material does not affect the focal length of the optical imaging system.

The structural parameters of each lens of the optical imaging system according to an embodiment of the present invention are specifically shown in table 1. In table 1, the unit of the radius of curvature and the thickness is mm, wherein surfaces 1 to 18 sequentially represent the surfaces from the object side to the image side, and surfaces 1 to 18 sequentially represent a diaphragm, a first lens object side surface, a first lens image side surface, a second lens object side surface, a second lens image side surface, a third lens object side surface, a third lens image side surface, a fourth lens object side surface, a fourth lens image side surface, a fifth lens object side surface, a fifth lens image side surface, a sixth lens object side surface, a sixth lens image side surface, a seventh lens object side surface, a seventh lens image side surface, an infrared filter object side surface, an infrared filter image side surface, and an image side surface.

TABLE 1

The focal length and power distribution of each lens in the embodiment of the invention are shown in table 2:

TABLE 2

Lens and lens assembly	Focal length	Capability of
			1	14.5	0.07
2	-23.9	-0.04
			3	31.0	0.03
4	12.5	0.08
			5	-12.2	-0.08
6	4.1	0.24
			7	-3.8	-0.27

In the embodiment of the invention, each lens mostly adopts an aspheric surface mirror surface, namely, the curvature is continuously changed from the center of the lens to the periphery of the lens. The aspherical lens has a better curvature radius characteristic than a spherical lens having a constant curvature, and has advantages of improving distortion aberration and improving astigmatic aberration. After the aspheric lens is adopted, the aberration generated during imaging can be eliminated as much as possible, thereby improving the imaging quality. Alternatively, at least one of the object-side surface and the image-side surface of each of the first lens 101 to the seventh lens 107 may be an aspherical surface. Further, the object-side surface and the image-side surface of each of the first lens 101 to the seventh lens 107 are aspherical surfaces.

The aspherical surface coefficients of the lenses in this example are specifically shown in table 3, in which a4 to a16 represent the 4 th to 16 th order aspherical high-order coefficient of each lens surface, respectively.

TABLE 3

	K	A 2	A4	A6	A8	A10	A12	A14	A16
										2 noodles	- 1.2132 45	0	0.00075 3607	0.00069 3717	0.00047 5241	- 0.000 3621	0.00026 5315	- 2.1392E -05	1.37E-06
3 side of flour	18.292 63	0	- 0.00323 9808	0.00191 5399	- 0.00257 9668	- 1.812 E-05	0.00022 8359	- 2.92314 E-07	6.4E-07
										4 sides	- 5.1430 15	0	- 0.01427 584	0.00265 2598	- 0.00479 8855	0.000 29835	- 3.3437E -05	1.10863 E-05	-1.6E-06
5 noodles	- 6.2688 41	0	- 0.00748 751	0.00134 7934	- 0.00157 7331	- 0.000 203	2.21942 E-05	3.2503E -07	-3.7E-07
										6 noodles	- 11.233 75	0	- 0.00127 599	- 0.00028 9602	0.00039 0144	- 4.809 E-05	- 1.50841 E-05	- 3.77501 E-06	-1.6E-07
7 noodles	0	0	- 0.00346 3266	7.39124 E-05	- 0.00024 8091	2.545 5E-06	- 3.52975 E-06	- 4.97451 E-07	-1.7E-07
										8 noodles	- 20.938 893	0	- 0.00530 9207	- 0.00023 8138	0.00037 0728	- 8.139 E-05	- 8.58703 E-06	1.52836 E-06	-1E-08
9 noodles	14.161 061	0	- 0.00154 3806	- 0.00067 5079	0.00031 4455	- 1.18E -05	- 2.16521 E-06	- 1.83343 E-08	1.61E-08
										10 noodles	- 1.6487 06	0	0.01424 837	- 0.00392 2875	0.00611 0576	- 0.000 6478	5.1664E -05	- 2.09629 E-06	6.96E-09
11 noodles	- 4.1421 9	0	0.00376 6462	- 0.00126 9523	0.00182 4573	- 0.000 165	1.14879 E-05	- 3.36458 E-07	-7.9E-10
										12 sides	- 2.6699 56	0	- 0.00629 2392	0.00076 3933	- 0.00050 7174	1.096 7E-05	1.04337 E-07	- 4.13694 E-09	3.28E-11
13 noodles	- 3.9461 1	0	- 0.00168 9916	1.64643 E-05	0.00058 9108	- 5.884 E-05	2.23586 E-06	- 3.0699E -08	-9.1E-13
										14 sides	- 101.69 9343	0	- 0.00532 9653	0.00016 7578	- 7.97919 E-06	2.864 4E-07	5.57428 E-09	- 5.24994 E-10	1.86E-13
15 noodles	- 4.7810 84	0	- 0.00305 8406	0.00013 1082	- 4.11373 E-05	7.866 6E-07	- 1.03635 E-08	7.25439 E-11	4.99E-14

FIG. 2 shows a positional chromatic aberration profile of an optical imaging system of an embodiment of the invention; FIG. 3 shows a chromatic aberration of magnification distribution diagram of an optical imaging system of an embodiment of the invention; fig. 4A and 4B show field curvature and distortion diagrams of the optical imaging system according to the embodiment of the present invention. As can be understood by those skilled in the art from fig. 2 to fig. 4B, the optical imaging system of the embodiment of the present invention has small chromatic aberration and distortion, and has excellent imaging effect.

In summary, the optical imaging system of the embodiment of the invention adopts the design scheme of the all-plastic lens, has high miniaturization degree and light overall weight, and has better imaging quality.

The optical imaging system 100 of the embodiment of the present invention can be applied to an electronic device. Therefore, an embodiment of the present invention may also provide an electronic apparatus, and the electronic apparatus according to the embodiment of the present invention may include, but is not limited to, an information terminal device such as a smart phone, a mobile phone, a Personal Digital Assistant (PDA), a game machine, a Personal Computer (PC), a camera, a smart watch, a tablet Computer, a handheld cradle head, or a household appliance with a photographing function.

The electronic device according to the embodiment of the present invention includes the optical imaging system 100 according to the above-described various embodiments, and a photosensitive element (not shown) disposed on the image side of the optical imaging system 100.

The photosensitive element may provide an imaging surface on which light refracted through the lens is imaged. In addition, the photosensitive elements may convert the optical signals imaged on the imaging surface into electrical signals for use by a computer or other suitable electronic device. The photosensitive element may be a Complementary Metal Oxide Semiconductor (CMOS) image sensor or a Charge-coupled Device (CCD) image sensor.

In some embodiments, the size of the photosensitive element is greater than or equal to 1 inch.

In the electronic device of the embodiment of the invention, the optical imaging system 100 is designed by all plastic, the optical length of the lens can be less than 20mm, and the aperture can be 2.0.

The electronic device of the embodiment of the present invention further includes a focusing motor (not shown) for driving the optical imaging system 100 to perform focusing. In some embodiments, the focus Motor is an ultrasonic Motor (USM).

The electronic device provided by the embodiment of the invention meets the requirements of miniaturization, large aperture, variable aperture, small distortion and high pixel on the basis of meeting a large-size photosensitive element. Moreover, the USM motor is used for focusing, so that the problem of picture shaking is solved, and the whole module is miniaturized.

Other advantageous technical effects of the electronic device according to the embodiment of the present invention are similar to those of the optical imaging system 100, and therefore are not described herein again.

It will be understood by those skilled in the art that all of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and all of the processes or elements of any method or apparatus so disclosed, may be combined in any combination, except combinations where such features are mutually exclusive. Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise.

Furthermore, those skilled in the art will appreciate that while some embodiments described herein include some features included in other embodiments, rather than other features, combinations of features of different embodiments are meant to be within the scope of the invention and form different embodiments. For example, in the claims, any of the claimed embodiments may be used in any combination.

Technical terms used in the embodiments of the present invention are only used for illustrating specific embodiments and are not intended to limit the present invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. Further, the use of "including" and/or "comprising" in the specification is intended to specify the presence of stated features, integers, steps, operations, elements, and/or components, but does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, and/or components.

The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below, if any, are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the present invention has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the invention in the form disclosed. Various modifications and alterations to this invention will become apparent to those skilled in the art without departing from the scope and spirit of this invention. The embodiments described herein are further intended to explain the principles of the invention and its practical application and to enable others skilled in the art to understand the invention.

The flow chart described in the present invention is only an example, and various modifications can be made to the diagram or the steps in the present invention without departing from the spirit of the present invention. For instance, the steps may be performed in a differing order, or steps may be added, deleted or modified. It will be understood by those skilled in the art that all or a portion of the above-described embodiments may be practiced and equivalents thereof may be resorted to as falling within the scope of the invention as claimed.

Claims

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

2. The optical imaging system of claim 1, wherein the number of the lenses of the optical imaging system is seven, and the first lens to the seventh lens are all plastic lenses.

3. The optical imaging system of claim 1, further comprising a stop positioned in front of an object side surface of the third lens.

4. The optical imaging system of claim 3, wherein the stop is positioned in front of an object side surface of the first lens.

5. The optical imaging system of claim 3, wherein the diaphragm is an iris diaphragm or a non-iris diaphragm.

6. The optical imaging system of claim 1, wherein at least one inflection point exists on both the object side and the image side of the seventh lens.

7. The optical imaging system of claim 6, wherein the image side surface of the seventh lens varies from concave to convex from paraxial to peripheral.

8. The optical imaging system of claim 1, wherein the optical imaging system satisfies: 0.4< f/TTL <1.0, wherein f is the effective focal length of the optical imaging system, and TTL is the on-axis distance from the object side surface of the first lens to the imaging surface.

9. The optical imaging system of claim 1, wherein the first lens satisfies: 0.25< | (R11-R12)/(R11+ R12) | <0.5, where R11 is the radius of curvature of the object-side surface of the first lens and R12 is the radius of curvature of the image-side surface of the first lens.

10. The optical imaging system of claim 1, wherein the second lens satisfies: 0< | (R12-R21)/(R21+ R12) | <0.3, where R21 is the radius of curvature of the object-side surface of the second lens and R12 is the radius of curvature of the image-side surface of the first lens.

11. The optical imaging system of claim 1, wherein the third lens satisfies: f3/f is more than or equal to 3.0 and less than or equal to 5.0, wherein f is the effective focal length of the optical imaging system, and f3 is the effective focal length of the third lens.

12. The optical imaging system of claim 1, wherein the fourth lens satisfies: 1.5< nd ≦ 1.8, where nd is the refractive index of the fourth lens.

13. The optical imaging system of claim 1, wherein the fifth lens satisfies: 0.15 ≦ CT5 ≦ 0.35, where CT5 is the center thickness of the fifth lens.

14. The optical imaging system of claim 1, wherein the sixth lens satisfies: 0 ≦ CT6/ET6 ≦ 3.0, where CT6 is the center thickness of the sixth lens and ET6 is the edge thickness of the sixth lens.

15. The optical imaging system of claim 1, wherein the sixth lens satisfies: 0< L67/TTL <0.1, where TTL is an on-axis distance from an object-side surface of the first lens element to an image plane, and L67 is an on-axis distance from an image-side surface of the sixth lens element to an object-side surface of the seventh lens element.

16. The optical imaging system of claim 1, wherein the fourth lens is an aspheric lens.

17. The optical imaging system of claim 16, wherein the first through seventh lenses are aspheric lenses.

18. An electronic device, comprising:

the optical imaging system of any one of claims 1 to 17; and

a photosensitive element disposed on an image side of the optical imaging system.

19. The electronic device of claim 18, wherein the size of the light sensing element is greater than or equal to 1 inch.

20. The electronic device of claim 18, further comprising: and the focusing motor is used for driving the optical imaging system to focus, and the focusing motor is an ultrasonic motor.