CN211554453U

CN211554453U - Optical imaging system, image capturing device with optical imaging system and electronic device with optical imaging system

Info

Publication number: CN211554453U
Application number: CN202020076857.2U
Authority: CN
Inventors: 张文燕; 刘彬彬; 李明; 邹海荣
Original assignee: OFilm Tech Co Ltd
Current assignee: Jiangxi Jingchao Optical Co Ltd
Priority date: 2020-01-14
Filing date: 2020-01-14
Publication date: 2020-09-22
Anticipated expiration: 2030-01-14

Abstract

The utility model discloses an optical imaging system and get for instance device, electron device that has it, optical imaging system includes: the optical lens group comprises a first lens, a second lens, a third lens and a fourth lens which are sequentially arranged along the axial direction, wherein the object side surface of the first lens is a convex surface at the optical axis, the object side surface of the second lens is a convex surface at the optical axis, the image side surface of the second lens is a concave surface at the optical axis, the object side surface of the fourth lens is a convex surface at the optical axis, and the image side surface of the fourth lens is a concave surface at the optical axis; wherein the optical imaging system satisfies: TL/Imgh is less than 1.5, wherein TTL is the distance between the object side surface of the first lens and the imaging surface on the optical axis, and Imgh is half of the diagonal length of the effective pixel area on the imaging surface. According to the utility model discloses an optical imaging system can have miniaturization and high definition simultaneously concurrently and shoot, has effectively promoted the shooting effect, can satisfy the shooting demand of user to camera lens.

Description

Optical imaging system, image capturing device with optical imaging system and electronic device with optical imaging system

Technical Field

The utility model belongs to the technical field of the optical imaging technique and specifically relates to an optical imaging system and get for instance device, electron device that has it.

Background

Along with the wide application of miniature camera in the electronic product of cell-phone, panel computer, unmanned aerial vehicle, computer, the innovation of camera lens shooting effect becomes one of the focus that people paid attention to in the improvement of novel electronic product, becomes an important content of science and technology improvement simultaneously. At present, people can not meet the shooting requirements of modern camera lenses on the shooting effect of visible light, the latest infrared light wave detection camera can directly record depth information to process photos, and can also perform blurring in different degrees on scenes and people in different depths, so that the shooting effect is greatly improved. Therefore, an infrared camera having high-definition shooting quality becomes an important point of design.

In the related art, a micro camera for infrared band imaging cannot meet the requirement of high-definition image shooting.

SUMMERY OF THE UTILITY MODEL

The utility model discloses aim at solving one of the technical problem that exists among the prior art at least. To this end, an object of the present invention is to provide an optical imaging system which can realize high definition shooting while realizing miniaturization.

Another object of the present invention is to provide an image capturing device with the above optical imaging system.

Another object of the present invention is to provide an electronic device having the image capturing device.

According to the utility model discloses optical imaging system of first aspect embodiment includes: the optical lens group comprises a first lens, a second lens, a third lens and a fourth lens which are sequentially arranged along the axial direction, the first lens, the second lens, the third lens and the fourth lens have bending force, the object side surface of the first lens is a convex surface at the optical axis, the object side surface of the second lens is a convex surface at the optical axis, the image side surface of the second lens is a concave surface at the optical axis, the second lens is provided with at least one reverse curvature point, the object side surface of the fourth lens is a convex surface at the optical axis, and the image side surface of the fourth lens is a concave surface at the optical axis; wherein the optical imaging system satisfies: TL/Imgh is less than 1.5, wherein TTL is the distance between the object side surface of the first lens and the imaging surface on the optical axis, and Imgh is half of the diagonal length of the effective pixel area on the imaging surface.

According to the utility model discloses optical imaging system, through setting up the first lens that has the power of buckling that sets gradually along the axial, the second lens, third lens and fourth lens, and make the object side of first lens to the imaging plane on the distance TTL of optical axis and imaging plane effective pixel region diagonal length's half Imgh satisfy relational TTL/Imgh < 1.5, make optical lens group have miniaturization and high definition simultaneously and shoot concurrently, effectively promoted the shooting effect, can satisfy the shooting demand of user to camera lens.

According to some embodiments of the invention, the effective aperture diameter of the first lens is L, wherein L satisfies: L/Imgh is more than 0.3 and less than 0.7. Therefore, the definition of the shot image is further ensured by enabling the L/Imgh to be more than 0.3 and less than 0.7, and the requirements of users are fully met.

According to some embodiments of the present invention, the diaphragm number of the optical lens group is Fno, wherein Fno satisfies: Fno/TTL is less than 0.4. Therefore, the Fno/TTL is smaller than 0.4, the optical imaging system can have both large aperture and miniaturization, and provide enough light flux for the optical imaging system, so that the high-quality and high-definition shooting requirement is met.

According to some embodiments of the present invention, the optical lens group further comprises a diaphragm, the diameter of the diaphragm aperture is D, wherein D satisfies: TTL/D is more than 1.5 and less than 3.0. Therefore, the optical imaging system can simultaneously meet the optimization of optical performance and the miniaturization of the structure by enabling TTL/D to be more than 1.5 to be less than 3.0.

According to some embodiments of the invention, the total effective focal length of the optical lens group is f, wherein f satisfies: TTL/f is more than 1.0 and less than 2.0. Therefore, by enabling TTL/f to be more than 1.0 and less than 2.0, the miniaturization of the optical lens is realized, and meanwhile, light can be guaranteed to be better converged on an imaging surface.

According to the utility model discloses a some embodiments, optical lens group still includes the diaphragm, the diameter in diaphragm aperture is D, optical lens group's diaphragm number is Fno, wherein, D, Fno satisfies: d is more than 2 and less than 3. Therefore, the proportion relation between the diameter of the aperture of the diaphragm and the diaphragm number of the optical lens group is reasonably controlled by enabling 2 to be less than DxFNO to be less than 3, and the optical imaging system can be guaranteed to have the best light transmission amount and picture definition.

According to some embodiments of the invention, the first lens has an optical effective focal length of f₁A total effective focal length of the optical lens group is f, wherein f₁F satisfies: -0.35 < f/f₁Is less than 0.35. By the arrangement, the sensitivity of the optical imaging system can be reduced, and the shooting requirement is met.

According to some embodiments of the present invention, the shortest distance from the image side surface of the fourth lens element to the imaging plane parallel to the optical axis is FBL, wherein FBL satisfies: FBL/TTL is more than 0.1 and less than 0.25. So set up, can guarantee when making optical imaging system compromise the camera lens miniaturization that get for instance the camera lens have sufficient space of focusing in optical lens group's installation to promote optical lens group's equipment yield. Moreover, through the arrangement, the focal depth of the image taking lens can be widened to acquire more depth information.

According to some embodiments of the invention, the radius of curvature of the object-side surface of the first lens is R₁The curvature radius of the image side surface of the first lens is R₂The focal length of the first lens is f₁Wherein, said R₁、R₂And f₁Satisfies the following conditions: -1.5 < (R)₁+R₂)/f₁Is less than 2. Thus, by making-1.5 < (R)₁+R₂)/f₁And (2) the imaging effect of the optical imaging system can be further ensured, and the shot picture is clearer.

According to some embodiments of the invention, the radius of curvature of the object side surface of the third lens is R₆The curvature radius of the image side surface of the third lens is R₇Wherein, said R₆、R₇Satisfies the following conditions: -8 < R₆/R₇Is less than 3.5. Therefore, when the lens group meets the formula, the curvature radius of the object side surface and the curvature radius of the image side surface of the third lens are more reasonable, the incidence angle can be increased to meet the requirement of the image height of the optical imaging system, meanwhile, the sensitivity of the system can be reduced, and the assembly stability is improved.

According to some embodiments of the invention, the third lens has an optical effective focal length of f₃A total effective focal length of the optical lens group is f, wherein f₃F satisfies: -40 < f₃The/f is less than 6. Whereby by making-40 < f₃And f is less than 6, and the ratio of the optical effective focal length of the third lens to the total effective focal length of the optical lens group can effectively reduce the total length of the optical imaging system and is favorable for converging light rays on an imaging surface.

According to some embodiments of the invention, the radius of curvature of the object side surface of the fourth lens is R₈The curvature radius of the image side surface of the fourth lens is R₉Wherein, said R₈、R₉Satisfies the following conditions: 0.4 < (R)₈×R₉)/(R₈+R₉) Is less than 0.55. Therefore, the longitudinal spherical aberration of the optical imaging system can be reasonably corrected, the distortion aberration and astigmatism are improved, the sensitivity of the optical imaging system is reduced, and the assembly stability is improved.

According to some embodiments of the invention, the third lens has a maximum optically effective area edge thickness ET₃The thickness of the third lens on the optical axis is CT₃Wherein, the ET₃、CT₃Satisfies the following conditions: ET 0.2 <₃/CT₃Is less than 0.8. So set up, can guarantee sufficient tolerance allowance, improve the shaping yield.

According to the utility modelIn some novel embodiments, the radius of curvature of the object-side surface of the second lens is R₄The curvature radius of the image side surface of the second lens is R₅Wherein, said R₄、R₅Satisfies the following conditions: -15 < (R)₄+R₅)/(R₄-R₅) Is < 90. Thus, by making-15 < (R)₄+R₅)/(R₄-R₅) < 90, the sensitivity of the optical imaging system can be reduced, and the process yield can be ensured.

According to the utility model discloses get for instance device of second aspect embodiment, include: a photosensitive element; an optical imaging system according to an embodiment of the above first aspect of the present invention.

According to the utility model discloses get for instance device, through adopting above-mentioned optical imaging system, the quantity of camera lens is less, is favorable to realizing the miniaturized design, and can realize that the high definition shoots, has promoted and has got for instance the holistic performance of device.

According to the utility model discloses third aspect embodiment's electronic device includes: a housing; get for instance the device, get for instance the device for the instance according to the utility model discloses the device for getting for instance of above-mentioned second aspect embodiment.

According to the utility model discloses electronic device gets for instance the device through adopting the aforesaid, makes electronic device have miniaturization and high definition advantage concurrently, fully provided user's demand.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

fig. 1 is a schematic structural diagram of an optical imaging system according to a first embodiment of the present invention;

FIG. 2 is a plot of longitudinal spherical aberration, astigmatism and distortion for the optical imaging system shown in FIG. 1;

fig. 3 is a schematic structural diagram of an optical imaging system according to a second embodiment of the present invention;

FIG. 4 is a plot of longitudinal spherical aberration, astigmatism and distortion for the optical imaging system shown in FIG. 3;

fig. 5 is a schematic structural view of an optical imaging system according to a third embodiment of the present invention;

FIG. 6 is a plot of longitudinal spherical aberration, astigmatism and distortion for the optical imaging system shown in FIG. 5;

fig. 7 is a schematic structural view of an optical imaging system according to a fourth embodiment of the present invention;

FIG. 8 is a plot of longitudinal spherical aberration, astigmatism and distortion for the optical imaging system shown in FIG. 7;

fig. 9 is a schematic structural view of an optical imaging system according to a fifth embodiment of the present invention;

FIG. 10 is a plot of longitudinal spherical aberration, astigmatism and distortion for the optical imaging system shown in FIG. 9;

fig. 11 is a schematic structural view of an optical imaging system according to a sixth embodiment of the present invention;

FIG. 12 is a plot of longitudinal spherical aberration, astigmatism and distortion for the optical imaging system shown in FIG. 11;

fig. 13 is a schematic structural view of an optical imaging system according to a seventh embodiment of the present invention;

FIG. 14 is a plot of longitudinal spherical aberration, astigmatism and distortion for the optical imaging system shown in FIG. 13;

fig. 15 is a schematic structural view of an optical imaging system according to an eighth embodiment of the present invention;

FIG. 16 is a plot of longitudinal spherical aberration, astigmatism and distortion for the optical imaging system shown in FIG. 15;

fig. 17 is a schematic structural view of an optical imaging system according to a ninth embodiment of the present invention;

FIG. 18 is a plot of longitudinal spherical aberration, astigmatism and distortion for the optical imaging system shown in FIG. 17;

fig. 19 is a schematic configuration diagram of an optical imaging system according to a tenth embodiment of the present invention;

fig. 20 is a graph of longitudinal spherical aberration, astigmatism and distortion of the optical imaging system shown in fig. 19.

Reference numerals:

100: an optical imaging system;

1: a first lens; 2: a second lens; 3: a third lens;

4: a fourth lens; 5: a diaphragm; 6: an infrared band pass filter.

Detailed Description

Embodiments of the present invention are described in detail below, and the embodiments described with reference to the drawings are exemplary.

An optical imaging system 100 according to an embodiment of the first aspect of the present invention is described below with reference to fig. 1-20.

As shown in fig. 1, 3, 5, 7, 9, 11, 13, 15, 17 and 19, an optical imaging system 100 according to an embodiment of the present invention includes an optical lens group.

Specifically, the optical lens assembly includes a first lens 1, a second lens 2, a third lens 3, and a fourth lens 4 sequentially arranged along an axial direction, the first lens 1, the second lens 2, the third lens 3, and the fourth lens 4 have a bending force, an object-side surface of the first lens 1 is a convex surface on an optical axis, an object-side surface of the second lens 2 is a convex surface on the optical axis, an image-side surface is a concave surface on the optical axis, the second lens 2 is provided with at least one inflection point, the object-side surface of the fourth lens 4 is a convex surface on the optical axis, and the image-side surface is a concave surface on the optical axis. Wherein the optical imaging system 100 satisfies: TTL/Imgh is less than 1.5, wherein TTL is the distance between the object side surface of the first lens 1 and the imaging surface on the optical axis, and Imgh is half of the diagonal length of the effective pixel area on the imaging surface.

For example, in the examples of fig. 1, 3, 5, 7, 9, 11, 13, 15, 17, and 19, the photosensitive element is disposed on the image side of the fourth lens element 4, the object-side surface of the fourth lens element 4 is convex at the optical axis, and the image-side surface of the fourth lens element 4 is concave at the optical axis, so that the curvature of field of the optical imaging system 100 can be effectively corrected, and the object can be imaged on the imaging plane in a flat manner. When optical imaging system 100 satisfies TTL/Imgh < 1.5, it can have miniaturization and high definition shooting at the same time, and compared with the traditional miniature camera, it has a bigger light-entering amount, effectively improves the shooting effect, and satisfies the shooting requirement of the user to the camera lens.

According to the utility model discloses optical imaging system 100, through setting up the first lens 1 that has the power of buckling that sets gradually along the axial, second lens 2, third lens 3 and fourth lens 4, and make the object side of first lens 1 to the imaging surface on optical axis apart from TTL and the imaging surface on effective pixel region diagonal length half Imgh satisfy relational TTL/Imgh < 1.5, make optical lens group have miniaturization and high definition simultaneously and shoot, effectively promoted the shooting effect, can satisfy the shooting demand of user to camera lens.

In some embodiments of the present invention, referring to fig. 1-20, the effective aperture diameter of the first lens 1 is L, wherein L satisfies: L/Imgh is more than 0.3 and less than 0.7. It should be noted that, because the effective aperture diameter of the first lens element 1 determines the amount of light passing through the whole optical imaging system 100, and the size of the photosensitive surface determines the image definition and the pixel size of the whole camera system, the two are reasonably proportioned to ensure sufficient amount of light passing through and the definition of the photographed image. If L/Imgh is greater than 0.7, the exposure is too large, the brightness is too high, and the picture quality is influenced; if L/Imgh < 0.3, the amount of light passing is insufficient, and the relative brightness of the light is insufficient, resulting in a decrease in the sharpness of the screen. Therefore, the definition of the shot image is further ensured by enabling the L/Imgh to be more than 0.3 and less than 0.7, and the requirements of users are fully met.

Further, referring to fig. 1 to 20, the optical lens group has an f-number Fno, where Fno satisfies: Fno/TTL is less than 0.4. When Fno/TTL >0.4, the optical imaging system 100 can be miniaturized and also insufficient amount of light can be transmitted, which degrades the sharpness of the captured image. Therefore, the optical imaging system 100 can have both large aperture and miniaturization by enabling Fno/TTL to be less than 0.4, and provide sufficient light flux for the optical imaging system 100, thereby satisfying high-quality and high-definition shooting requirements.

In a further embodiment of the present invention, as shown in fig. 1, fig. 3, fig. 5, fig. 7, fig. 9, fig. 11, fig. 13, fig. 15, fig. 17 and fig. 19, the optical lens group further includes a diaphragm 5, a diameter of an aperture of the diaphragm 5 is D, where D satisfies: TTL/D is more than 1.5 and less than 3.0. When TTL/D is less than 1.5, the light-transmitting aperture is overlarge when the miniaturization design is met, so that marginal light rays enter the optical imaging system 100, and the imaging quality is reduced; if TTL/D >3, when satisfying the miniaturization, can cause 5 light-passing bores undersize of diaphragm, can't satisfy the system and lead to the fact the amount of light, can't realize the high definition of dim light scene and shoot the requirement. Thus, by setting TTL/D to 1.5 < 3.0, the optical imaging system 100 can simultaneously satisfy the optimization of optical performance and the miniaturization of the structure.

Optionally, referring to fig. 1-20, the total effective focal length of the optical lens group is f, where f satisfies: TTL/f is more than 1.0 and less than 2.0. For example, when TTL/f is less than or equal to 1.0, the optical length of the optical lens group is too short, which increases the system sensitivity and is not conducive to the convergence of light on the image plane; when TTL/f is greater than or equal to 2, the optical length of the optical lens group is too long, which may cause the angle of the main light beam entering the imaging surface to be too large, and the light beam at the edge of the imaging surface of the optical imaging system 100 may not be imaged on the photosensitive surface, resulting in incomplete imaging information. Therefore, by enabling TTL/f to be more than 1.0 and less than 2.0, the miniaturization of the optical lens is realized, and meanwhile, light can be guaranteed to be better converged on an imaging surface.

Optionally, as shown in fig. 1, 3, 5, 7, 9, 11, 13, 15, 17 and 19, the optical lens group further includes a stop 5, a diameter of an aperture of the stop 5 is D, and an f-number of the optical lens group is Fno, where D, Fno satisfies: d is more than 2 and less than 3. For example, when D × FNO < 2, it is not favorable for light to converge on the imaging plane, and a large amount of stray light is generated, resulting in degradation of the photographing quality; when D is multiplied by FNO >3, the aperture is too large, the marginal rays are not reasonably intercepted, the field curvature is increased, and a distorted image of the edge is formed. Therefore, the optical imaging system 100 can be ensured to have the best light transmission amount and picture definition by making 2 < DxFNO < 3 and reasonably controlling the matching relation between the diameter of the aperture of the diaphragm 5 and the diaphragm number of the optical lens group.

In some embodiments of the present invention, the optical effective focal length of the first lens element 1 is f1, and the total effective focal length of the optical lens assembly is f, wherein f₁F satisfies: -0.35 < f/f₁Is less than 0.35. It should be noted that the first lens 1 provides all optical information from the object space to the image space for the whole optical lens group, and the aperture size and the focal length of the first lens 1 determine the acquisition of the optical information from the object space by the optical imaging system 100. When f/f1 is more than or equal to 0.35, the sensitivity of the optical imaging system 100 is increased, the processing technology is difficult, and the aberration generated by the first lens 1 is difficult to correct, so that the shooting requirement is difficult to meet; when f/f₁When the aberration generated by the first lens 1 is less than-0.35, the aberration cannot be corrected. With this arrangement, the sensitivity of the optical imaging system 100 can be reduced, and the shooting requirements can be satisfied.

Further, referring to fig. 1 to 20, the shortest distance from the image-side surface of the fourth lens element 4 to the image plane parallel to the optical axis is FBL, where FBL satisfies: FBL/TTL is more than 0.1 and less than 0.25. With such an arrangement, the optical imaging system 100 can ensure that the image capturing lens has sufficient focusing space in the installation process of the optical lens assembly while taking the lens into consideration miniaturization, thereby improving the assembly yield of the optical lens assembly. Moreover, through the arrangement, the focal depth of the image taking lens can be widened to acquire more depth information.

In some embodiments of the present invention, the radius of curvature of the object-side surface of the first lens element 1 is R₁The radius of curvature of the image-side surface of the first lens element 1 is R₂The focal length of the first lens 1 is f₁Wherein R is₁、R₂And f₁Satisfies the following conditions: -1.5 < (R)₁+R₂)/f₁Is less than 2. For example, when (R)₁+R₂) When/f 1 is more than or equal to 2.5, the sensitivity of the optical imaging system 100 is increased, which is not beneficial to processing; (R)₃+R₄) When the/f 1 is less than or equal to-1.5, the optical imaging system 100 is not favorable for obtaining object space light information, and the imaging effect cannot reach the expected design requirement. Thus, by making-1.5 < (R)₁+R₂)/f₁< 2, the optical imaging system can be further ensured100, the shot picture is clearer.

Further, the radius of curvature of the object-side surface of the third lens element 3 is R₆The radius of curvature of the image-side surface of the third lens element 3 is R₇Wherein R is₆、R₇Satisfies the following conditions: -8 < R₆/R₇Is less than 3.5. Therefore, when the lens group satisfies the above formula, the curvature radius of the object-side surface and the curvature radius of the image-side surface of the third lens element 3 are more reasonable, the incident angle can be increased to satisfy the requirement of the image height of the optical imaging system 100, and meanwhile, the sensitivity of the optical imaging system 100 can be reduced, and the assembly stability can be improved.

In some embodiments of the present invention, the third lens 3 has an optical effective focal length f₃The total effective focal length of the optical lens group is f, wherein f₃F satisfies: -40 < f₃The/f is less than 6. For example, when f₃When/f is less than or equal to-40, the total length of the optical imaging system 100 is too large, and the assembly sensitivity is increased; when f is₃When/f is larger than or equal to 6, stray light of the lens can be increased, and imaging quality is affected. Whereby by making-40 < f₃And f is less than 6, and the ratio of the optical effective focal length of the third lens 3 to the total effective focal length of the optical lens group can effectively reduce the total length of the optical imaging system 100, thereby being beneficial to the convergence of light rays on an imaging surface.

In some embodiments of the present invention, the radius of curvature of the object-side surface of the fourth lens element 4 is R₈The radius of curvature of the image-side surface of the fourth lens element 4 is R₉Wherein R is₈、R₉Satisfies the following conditions: 0.4 < (R)₈×R₉)/(R₈+R₉) Is less than 0.55. Therefore, the longitudinal spherical aberration of the optical imaging system 100 can be reasonably corrected, the distortion aberration and astigmatism can be improved, the sensitivity of the optical imaging system 100 can be reduced, and the assembly stability can be improved.

In some embodiments of the present invention, the third lens 3 has a maximum optically effective area edge thickness ET₃The thickness of the third lens element 3 on the optical axis is CT₃Wherein, ET₃、CT₃Satisfies the following conditions: ET 0.2 <₃/CT₃Is less than 0.8. So arranged, enough tolerance margin can be ensuredAnd the forming yield is improved.

In some embodiments of the present invention, the radius of curvature of the object-side surface of the second lens element 2 is R₄The radius of curvature of the image-side surface of the second lens element 2 is R₅Wherein R is₄、R₅Satisfies the following conditions: -15 < (R)₄+R₅)/(R₄-R₅) Is < 90. For example, when (R)₄+R₅)/(R₄-R₅)>90 this results in a reduction in the yield of the optical lens set while increasing the sensitivity of the optical imaging system 100 when (R)₄+R₅)/(R₄-R₅) When < -15 >, the tolerance is too large, and the assembling performance of the optical lens group is deteriorated. Thus, by making-15 < (R)₄+R₅)/(R₄-R₅) < 90, the sensitivity of the optical imaging system 100 can be reduced, and the process yield can be ensured.

Alternatively, referring to fig. 1, 3, 5, 7, 9, 11 and 13, 15, 17 and 19, the diaphragm 5 is provided between the first lens 1 and the second lens 2. Accordingly, the influence of the stray light on the image can be further eliminated, the quality of the image can be improved, and the field angle of the optical imaging system 100 can be further enlarged.

Alternatively, the first lens 1, the second lens 2, the third lens 3, and the fourth lens 4 may be made of plastic or the like. Thereby, the optical lens group can be reduced in weight.

An optical imaging system 100 according to various embodiments of the present invention is described below with reference to fig. 1-20.

In the first embodiment, the first step is,

in this embodiment, as shown in fig. 1, the optical imaging system 100 includes, in order from the object side to the image side, a first lens 1, a diaphragm 5, a second lens 2, a third lens 3, and a fourth lens 4, and the longitudinal spherical aberration, astigmatism, and distortion curves of the optical imaging system 100 refer to fig. 2.

The first lens element 1 is made of plastic, the first lens element 1 has a negative refractive power, an object-side surface of the first lens element 1 is a convex surface on an optical axis, an image-side surface of the first lens element 1 is a concave surface on the optical axis, an object-side surface of the first lens element 1 is a concave surface on a circumference, the image-side surface of the first lens element 1 is a convex surface on the circumference, and both the object-side surface and the image-side surface of the first lens element 1 are aspheric surfaces. The second lens element 2 is made of plastic, the second lens element 2 has positive refractive power, an object-side surface of the second lens element 2 is convex at an optical axis, an image-side surface of the second lens element 2 is concave at the optical axis, an object-side surface of the second lens element 2 is concave at a circumference, the image-side surface of the second lens element 2 is convex at the circumference, and both the object-side surface and the image-side surface of the second lens element 2 are aspheric surfaces. The third lens element 3 is made of plastic, the third lens element 3 has positive refractive power, an object-side surface of the third lens element 3 is convex at an optical axis, an image-side surface of the third lens element 3 is also convex at the optical axis, an object-side surface of the third lens element 3 is convex at a circumference, the image-side surface of the third lens element 3 is convex at the circumference, and both the object-side surface and the image-side surface of the third lens element 3 are aspheric surfaces. The fourth lens element 4 is made of plastic, the fourth lens element 4 has positive refractive power, an object-side surface of the fourth lens element 4 is convex at an optical axis, an image-side surface of the fourth lens element 4 is concave at the optical axis, an object-side surface of the fourth lens element 4 is concave at a circumference, the image-side surface of the fourth lens element 4 is convex at the circumference, and both the object-side surface and the image-side surface of the fourth lens element 4 are aspheric surfaces. The imaging surface is arranged on the image side of the fourth lens 4, an infrared band-pass filter 6 is arranged between the fourth lens 4 and the imaging surface, the infrared band-pass filter 6 is made of glass and does not affect the focal length, and the photosensitive element is arranged on the imaging surface. The optical lens group only images at an infrared waveband, the infrared band-pass filter 6 filters imaging light entering the lens, ultraviolet waveband and visible light are filtered out, and only infrared light is allowed to pass. For example, referring to table one, the reference wavelength of the optical lens assembly is 940nm, which belongs to infrared light waves.

The detailed optical data of the first embodiment is shown in table one, the aspheric coefficients are shown in table two, the units of the curvature radius, the thickness and the focal length are millimeters, and the reference wavelength of the optical imaging system 100 is 940 nm. Wherein, the aspheric surface formula is:

z is the distance from the corresponding point on the aspheric surface to a plane tangent to the surface vertex, and r is the distance from the corresponding point on the aspheric surface to the optical axisThe distance, c, is the curvature of the aspheric vertex, k is the conic constant, and Ai is the coefficient corresponding to the i-th high-order term in the aspheric surface type formula.

In the first embodiment, the distance from the object-side surface of the first lens element 1 to the image plane on the optical axis is TTL, half of the diagonal length of the effective pixel area of the photosensitive element is Imgh, TTL/Imgh is 1.06, the effective aperture diameter of the first lens element 1 is L, L/Imgh is 0.48, the f-number of the optical lens group is Fno, Fno/TTL is 0.31, the diameter of the aperture of the stop 5 is D, TTL/D is 2.5, D × Fno is 2.47, the total effective focal length of the optical lens group is f, and the optical effective focal length of the first lens element 1 is f₁，TTL/f＝1.77，f/f₁-0.12; the shortest distance parallel to the optical axis from the image side surface of the fourth lens element 4 to the image plane is FBL, where FBL/TTL is 0.17; the radius of curvature of the object-side surface of the first lens element 1 is R₁The radius of curvature of the image-side surface of the first lens 1 is R2, (R1+ R2)/f1 is-0.28, the radius of curvature of the object-side surface of the third lens 3 is R6, the radius of curvature of the image-side surface of the third lens 3 is R7, R6/R7 is-2.72, the optically effective focal length of the third lens 3 is f3, f3/f is 3.8, the radius of curvature of the object-side surface of the fourth lens 4 is R8, the radius of curvature of the image-side surface of the fourth lens 4 is R9, (R8 × R9)/(R2 + R9) 6950.45, the edge thickness of the third lens 3 is ET3, the center thickness of the third lens 3 is CT3, ET3/CT3, the radius of curvature of the object-side surface of the second lens 2 is R4, the radius of curvature of the image-side surface of the second lens 2 is R8672, the radius of R5 is R5, and the imaging quality of the imaging system is improved by reducing the radius of the curvature of the R5, the radius of the R5, the imaging system is achieved by reducing the imaging system.

In the second embodiment, the first embodiment of the method,

as shown in fig. 3 and 4, the present embodiment has substantially the same structure as the first embodiment, wherein the same reference numerals are used for the same components, except that: the third lens 3 has a negative bending force,

the detailed optical data of the second embodiment is shown in table three, the aspheric coefficients are shown in table four, the units of the radius of curvature, the thickness and the focal length are millimeters, and the reference wavelength of the optical imaging system 100 is 940 nm.

In example two, TTL/Imgh is 1.06, L/Imgh is 0.49, Fno/TTL is 0.31, TTL/D is 2.54, D × Fno is 2.44, TTL/f is 1.75, f/f is 2.44₁＝-0.24，FBL/TTL＝0.17，(R₁+R₂)/f₁＝-1.27，R₆/R₇＝3.2，f₃/f＝-35.26，(R₈×R₉)/(R₈+R₉)＝0.44，ET₃/CT₃＝0.71，(R₄+R₅)/(R₄-R₅)＝-3.82。

The optical imaging system 100 of the present embodiment is similar to the optical imaging system 100 of the first embodiment in other structures, and therefore, will not be described in detail herein.

In the third embodiment, the first step is that,

as shown in fig. 5 and 6, the present embodiment has substantially the same structure as the first embodiment, wherein the same reference numerals are used for the same components, except that: the first lens 1 has a positive refracting power, and the fourth lens 4 has a negative refracting power.

The detailed optical data of the third embodiment is shown in table five, the aspheric coefficients are shown in table six, the units of the radius of curvature, the thickness and the focal length are millimeters, and the reference wavelength of the optical imaging system 100 is 940 nm.

In example three, TTL/Imgh is 1.06, L/Imgh is 0.48, Fno/TTL is 0.31, TTL/D is 2.49, D × Fno is 2.47, TTL/f is 1.74, f/f is 2.48₁＝0.07，FBL/TTL＝0.17，(R₁+R₂)/f₁＝0.60，R₆/R₇＝-5.33，f₃/f＝1.09，(R₈×R₉)/(R₈+R₉)＝0.44，ET₃/CT₃＝0.27，(R₄+R₅)/(R₄-R₅)＝60.67。

In the fourth embodiment, the first step is that,

as shown in fig. 7 and 8, the present embodiment has substantially the same structure as the first embodiment, wherein the same reference numerals are used for the same components, except that: the radii of curvature of the respective surfaces of the first lens 1, the second lens 2, the third lens 3, and the fourth lens 4 are different from those of the first embodiment.

Detailed optical data of example four is shown in table seven, aspheric coefficients thereof are shown in table eight, a unit of a radius of curvature, a thickness, and a focal length is in millimeters, and a reference wavelength of the optical imaging system 100 is 940 nm.

In example four, TTL/Imgh is 1.06, L/Imgh is 0.52, Fno/TTL is 0.28, TTL/D is 2.22, D × Fno is 2.48, TTL/f is 1.79, f/f is 2.52₁＝-0.33，FBL/TTL＝0.17，(R₁+R₂)/f₁＝-1.32，R₆/R₇＝-3.49，f₃/f＝3.80，(R₈×R₉)/(R₈+R₉)＝0.45，ET₃/CT₃＝0.40，(R₄+R₅)/(R₄-R₅)＝-6.62。

In the fifth embodiment, the first step is,

as shown in fig. 9 and 10, the present embodiment has substantially the same structure as the first embodiment, wherein the same reference numerals are used for the same components, except that: the radii of curvature of the respective surfaces of the first lens 1, the second lens 2, the third lens 3, and the fourth lens 4 are different from those of the first embodiment.

Example five detailed optical data are shown in table nine, aspheric coefficients are shown in table ten, radius of curvature, thickness and focal length are in millimeters, and the reference wavelength of the optical imaging system 100 is 940 nm.

In example five, TTL/Imgh ═1.06，L/Imgh＝0.55，Fno/TTL＝0.27，TTL/D＝2.10，D×FNO＝2.53，TTL/f＝1.79，f/f₁＝-0.26，FBL/TTL＝0.17，(R₁+R₂)/f₁＝-1.01，R₆/R₇＝-7.47，f₃/f＝4.60，(R₈×R₉)/(R₈+R₉)＝0.46，ET₃/CT₃＝0.41，(R₄+R₅)/(R₄-R₅)＝-4.71。

In the sixth embodiment, the process is carried out,

as shown in fig. 11 and 12, the present embodiment has substantially the same structure as the first embodiment, wherein the same reference numerals are used for the same components, except that: the radii of curvature of the respective surfaces of the first lens 1, the second lens 2, the third lens 3, and the fourth lens 4 are different from those of the first embodiment.

Example six detailed optical data are shown in table eleven, aspheric coefficients are shown in table twelve, radii of curvature, thickness and focal length are in millimeters, and the reference wavelength of the optical imaging system 100 is 940 nm.

In example six, TTL/Imgh is 1.06, L/Imgh is 0.55, Fno/TTL is 0.25, TTL/D is 2.07, D × Fno is 2.35, TTL/f is 1.79, f/f is 2.06₁＝-0.25，FBL/TTL＝0.17，(R₁+R₂)/f₁＝-1.04，R₆/R₇＝-4.76，f₃/f＝4.54，(R₈×R₉)/(R₈+R₉)＝0.46，ET₃/CT₃＝0.36，(R₄+R₅)/(R₄-R₅)＝-4.71。

In the seventh embodiment, the process is carried out,

as shown in fig. 13 and 14, the present embodiment has substantially the same structure as the first embodiment, wherein the same reference numerals are used for the same components, except that: the first lens element 1 has positive refractive power, and the object-side surface of the first lens element 1 is convex at the circumference.

Example seventy detailed optical data is shown in table thirteen, aspheric coefficients are shown in table fourteen, units of curvature radius, thickness and focal length are millimeters, and the reference wavelength of the optical imaging system 100 is 940 nm.

In example seven, TTL/Imgh is 1.21, L/Imgh is 0.55, Fno/TTL is 0.27, TTL/D is 2.59, D × Fno is 2.70, TTL/f is 1.74, f/f is 2.55₁＝0.06，FBL/TTL＝0.17，(R₁+R₂)/f₁＝0.49，R₆/R₇＝-3.32，f₃/f＝1.58，(R₈×R₉)/(R₈+R₉)＝0.48，ET₃/CT₃＝0.51，(R₄+R₅)/(R₄-R₅)＝87.21。

In the eighth embodiment, the method comprises the following steps of,

as shown in fig. 15 and 16, the present embodiment has substantially the same structure as the first embodiment, wherein the same reference numerals are used for the same components, except that: the first lens element 1 has positive refractive power, the third lens element 3 has negative refractive power, the object-side surface of the third lens element 3 is concave at the optical axis, and the object-side surface of the third lens element 3 is concave at the circumference.

Example eighthly detailed optical data are shown in table fifteen, aspheric coefficients are shown in table sixteen, radii of curvature, thickness and focal length are in millimeters, and the reference wavelength of the optical imaging system 100 is 940 nm.

In example eight, TTL/Imgh is 1.05, L/Imgh is 0.59, Fno/TTL is 0.27, TTL/D is 1.95, D × Fno is 2.68, TTL/f is 1.60, and f/f is 0.59₁＝0.21，FBL/TTL＝0.16，(R₁+R₂)/f₁＝0.38，R₆/R₇＝0.80，f₃/f＝-14.47，(R₈×R₉)/(R₈+R₉)＝0.49，ET₃/CT₃＝0.63，(R₄+R₅)/(R₄-R₅)＝-4.02。

In the ninth embodiment, the method of the present invention,

as shown in fig. 17 and 18, the present embodiment has substantially the same structure as the first embodiment, wherein the same reference numerals are used for the same components, except that: the first lens element 1 has positive refractive power, and the object-side surface of the first lens element 1 is convex at the circumference.

Example nine detailed optical data are shown in table seventeen, aspheric coefficients are shown in table eighteen, the units of radius of curvature, thickness and focal length are in millimeters, and the reference wavelength of the optical imaging system 100 is 940 nm.

In example nine, TTL/Imgh is 1.06, L/Imgh is 0.50, Fno/TTL is 0.31, TTL/D is 2.60, D × Fno is 2.37, TTL/f is 1.75, f/f is 2.37₁＝0.11，FBL/TTL＝0.17，(R₁+R₂)/f₁＝1.59，R₆/R₇＝-3.09，f₃/f＝1.58，(R₈×R₉)/(R₈+R₉)＝0.41，ET₃/CT₃＝0.48，(R₄+R₅)/(R₄-R₅)＝35.63。

In the embodiment example ten, the method comprises the following steps of,

as shown in fig. 19 and 20, the present embodiment has substantially the same structure as the ninth embodiment, in which the same reference numerals are used for the same components, except that: the second lens element 2 has negative refractive power, the image-side surface of the first lens element 1 is convex at the optical axis, the object-side surface of the first lens element 1 is concave at the circumference, and the image-side surface of the third lens element 3 is concave at the circumference.

Detailed optical data of the example are shown in table nineteen, aspheric coefficients thereof are shown in table twenty, a unit of a radius of curvature, a thickness, and a focal length is in millimeters, and a reference wavelength of the optical imaging system 100 is 940 nm.

In example ten, TTL/Imgh is 1.06, L/Imgh is 0.50, Fno/TTL is 0.31, TTL/D is 2.60, D × Fno is 2.37, TTL/f is 1.75, f/f is 2.37₁＝0.11，FBL/TTL＝0.17，(R₁+R₂)/f₁＝1.59，R₆/R₇＝-3.09，f₃/f＝1.58，(R₈×R₉)/(R₈+R₉)＝0.41，ET₃/CT₃＝0.48，(R₄+R₅)/(R₄-R₅)＝35.63。

The optical imaging system 100 of the present embodiment is similar to the optical imaging system 100 of the ninth embodiment in other structures, and therefore, will not be described in detail herein.

According to the image capturing device (not shown) of the embodiment of the second aspect of the present invention, including the photosensitive element and the optical imaging system 100, the optical imaging system 100 is the optical imaging system 100 according to the embodiment of the first aspect of the present invention.

According to the utility model discloses get for instance device, through adopting above-mentioned optical imaging system 100, the quantity of camera lens is less, is favorable to realizing the miniaturized design, and can realize that the high definition shoots, has promoted and has got for instance the holistic performance of device.

An electronic device (not shown) according to an embodiment of the third aspect of the present invention includes a housing (not shown) and an image capturing device. Get for instance the device for instance according to the utility model discloses above-mentioned second aspect embodiment gets for instance the device and installs on the casing and expose from the casing.

Other configurations and operations of the electronic device according to the embodiments of the present invention are known to those skilled in the art and will not be described in detail herein.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be construed as limiting the present invention.

In the description of the present invention, "the first feature", "the second feature", "the third feature", and "the fourth feature" may include one or more of the features.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example.

While embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. An optical imaging system, comprising:

the optical lens group comprises a first lens, a second lens, a third lens and a fourth lens which are sequentially arranged along the axial direction, the first lens, the second lens, the third lens and the fourth lens all have bending force, the object side surface of the first lens is a convex surface at the optical axis, the object side surface of the second lens is a convex surface at the optical axis, the image side surface of the second lens is a concave surface at the optical axis, the second lens is provided with at least one reverse bending point, the object side surface of the fourth lens is a convex surface at the optical axis, and the image side surface of the fourth lens is a concave surface at the optical axis;

wherein the optical imaging system satisfies:

TTL/Imgh＜1.5，

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

2. The optical imaging system of claim 1, wherein the first lens has an effective aperture diameter of L, wherein L satisfies:

0.3＜L/Imgh＜0.7。

3. the optical imaging system of claim 1, wherein an f-number of the optical lens group is Fno, wherein Fno satisfies:

Fno/TTL＜0.4。

4. the optical imaging system of claim 1, wherein the optical lens group further comprises a stop, the stop aperture having a diameter D, wherein D satisfies:

1.5＜TTL/D＜3.0。

5. the optical imaging system of claim 1, wherein the total effective focal length of the optical lens group is f, wherein f satisfies:

1.0＜TTL/f＜2.0。

6. the optical imaging system of claim 1, wherein the optical lens group further comprises a stop, the diameter of the stop aperture is D, the f-number of the optical lens group is Fno, wherein the D, Fno satisfies:

2＜D×FNO＜3。

7. the optical imaging system of claim 1, wherein the first lens has an optically effective focal length f₁A total effective focal length of the optical lens group is f, wherein f₁F satisfies:

-0.35＜f/f₁＜0.35。

8. the optical imaging system of claim 1, wherein a shortest distance from an image side surface of the fourth lens to an imaging plane parallel to the optical axis is FBL, wherein the FBL satisfies:

0.1＜FBL/TTL＜0.25。

9. the optical imaging system of claim 1, wherein the radius of curvature of the object-side surface of the first lens is R₁The curvature radius of the image side surface of the first lens is R₂The focal length of the first lens is f₁Wherein, said R₁、R₂And f₁Satisfies the following conditions:

-1.5＜(R₁+R₂)/f₁＜2。

10. the optical imaging system of claim 1, wherein the radius of curvature of the object-side surface of the third lens is R₆The curvature radius of the image side surface of the third lens is R₇Wherein, said R₆、R₇Satisfies the following conditions:

-8＜R₆/R₇＜3.5。

11. the optical imaging system of claim 1, wherein the third lens has an optically effective focal length f₃A total effective focal length of the optical lens group is f, wherein f₃F satisfies:

-40＜f₃/f＜6。

12. the optical imaging system of claim 1, wherein the fourth lens has a radius of curvature of the object-side surface of R₈The curvature radius of the image side surface of the fourth lens is R₉Wherein, said R₈、R₉Satisfies the following conditions:

0.4＜(R₈×R₉)/(R₈+R₉)＜0.55。

13. the optical imaging system of claim 1, wherein the third lens has a maximum optically effective area edge thickness ET₃The thickness of the third lens on the optical axis is CT₃Wherein, the ET₃、CT₃Satisfies the following conditions:

0.2＜ET₃/CT₃＜0.8。

14. the optical imaging system of claim 1, wherein the radius of curvature of the object-side surface of the second lens is R₄The curvature radius of the image side surface of the second lens is R₅Wherein, said R₄、R₅Satisfies the following conditions:

-15＜(R₄+R₅)/(R₄-R₅)＜90。

15. an image capturing apparatus, comprising:

a photosensitive element;

an optical imaging system according to any one of claims 1 to 14.

16. An electronic device, comprising:

a housing;

the image capturing apparatus according to claim 15, mounted on and exposed from the housing.