CN211698383U

CN211698383U - Optical imaging system, image capturing device with optical imaging system and electronic device with optical imaging system

Info

Publication number: CN211698383U
Application number: CN202020261602.3U
Authority: CN
Inventors: 蔡雄宇; 兰宾利; 赵迪; 周芮
Original assignee: Tianjin OFilm Opto Electronics Co Ltd
Current assignee: Jiangxi Oufei Optics Co ltd
Priority date: 2020-03-05
Filing date: 2020-03-05
Publication date: 2020-10-16
Anticipated expiration: 2030-03-05

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, a fourth lens, a fifth lens, a sixth lens, a seventh lens and an eighth lens which are sequentially arranged along the axial direction, the first lens, the second lens, the fifth lens, the sixth lens and the seventh lens all have positive bending force, and the third lens, the fourth lens and the eighth lens all have negative bending force. According to the utility model discloses an optical imaging system can carry out corresponding optimization setting to first lens to eighth lens, makes optical lens group's configuration more reasonable, when making optical imaging system satisfy long focal length, is favorable to realizing optical lens group's high pixelation, has improved optical imaging system's imaging quality.

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

In the related art, the telephoto lens has a long focal length, a small viewing angle, and a large image on a film, so that an image larger than that of a standard lens can be taken at the same distance, and the telephoto lens is suitable for taking a far object. For example, a forward-looking camera in the vehicle-mounted cameras provides reference for a driver in a blind spot area outside a human-eye observable area because the forward-looking camera needs to observe a long-distance image, so that the driver can master the road condition ahead in real time in the driving process, and the safety driving is guaranteed. Therefore, the forward looking camera should use a longer focal length. However, the existing telephoto lens, such as a front view camera among vehicle-mounted cameras, has difficulty in securing the whole pixels because it needs to capture an object to be observed at a long distance.

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. For this reason, an object of the present invention is to provide an optical imaging system that can satisfy high definition shooting while realizing a long focal length.

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, a fourth lens, a fifth lens, a sixth lens, a seventh lens and an eighth lens which are sequentially arranged along the axial direction, the first lens, the second lens, the fifth lens, the sixth lens and the seventh lens all have positive bending force, and the third lens, the fourth lens and the eighth lens all have negative bending force.

According to the utility model discloses optical imaging system, through making first lens, second lens, fifth lens, sixth lens and seventh lens all have positive power of buckling, make optical imaging system have sufficient ability of assembling, make optical imaging system's compact structure, avoid optical lens group's overall length overlength. By enabling the third lens, the fourth lens and the eighth lens to have negative bending force, light with a large visual angle can enter the optical imaging system. Meanwhile, the first lens to the eighth lens are correspondingly and optimally arranged, so that the configuration of the optical lens group is reasonable, the optical imaging system can meet the long focal length, the high pixelation of the optical lens group is facilitated, and the imaging quality of the optical imaging system is improved.

According to some embodiments of the present invention, 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 third lens is a convex surface at the optical axis, the image side surface of the third lens is a concave surface at the optical axis, and the second lens and the third lens are glued to each other. Therefore, the optical imaging system is compact in structure, miniaturization design is facilitated, and balance is achieved in reducing the size and improving the system resolving power by mutually gluing the second lens and the third lens. Moreover, the object side surfaces of the second lens and the third lens are convex at the optical axis and the image side surfaces of the second lens and the third lens are concave at the optical axis, so that the correction of the image plane curvature is facilitated, the assembly sensitivity is reduced, and the system resolution is improved.

According to some embodiments of the present invention, the object side and the image side of the fourth lens are concave surfaces at the optical axis, the object side and the image side of the fifth lens are convex surfaces at the optical axis, and the fourth lens and the fifth lens are glued to each other. Therefore, the fourth lens and the fifth lens are mutually glued, so that the structure of the optical imaging system can be more compact, and the miniaturization design can be realized. Further, the object-side surface of the fourth lens element is concave at the optical axis, which is advantageous for correcting astigmatism.

According to some embodiments of the present invention, the object side surface of the first lens element is a convex surface on the optical axis, the image side surface of the first lens element is a concave surface on the optical axis, the object side surface and the image side surface of the sixth lens element are convex surfaces on the optical axis, the object side surface of the seventh lens element is a convex surface on the optical axis, the image side surface of the seventh lens element is a flat surface or a concave surface on the optical axis, the object side surface of the eighth lens element is a concave surface on the optical axis, and the image side surface of the eighth lens element is a convex surface or a concave surface on the optical axis. This arrangement can enlarge the angle of view by making the object-side surface of the first lens convex on the optical axis and making the first lens have positive refractive power. Moreover, the image side surface of the first lens is concave at the optical axis, so that peripheral light rays with a large visual angle can enter the optical lens group, and the shooting range can be expanded.

According to some embodiments of the present invention, a filter film is disposed on an object side surface or an image side surface of one of the first lens element to the eighth lens element; or a filter is arranged between the image side of the eighth lens and the imaging surface. The filter film is used for cutting off the infrared wave band by transmitting visible light, and the independent arrangement of the optical filter is beneficial to the assembly process of the lens system; the filter film is arranged on the surface of the lens, so that the image plane color balance can be kept better. The photographing effect is close to the human eyes, and the imaging effect of the optical imaging system is ensured.

According to some embodiments of the invention, the effective focal length of the optical lens group is EFL, the focal length of the first lens is f₁Wherein, the EFL, f₁Satisfies the following conditions: f is more than 0₁The EFL is less than 2. Therefore, the first lens is the first lens from the object side to the image side of the optical imaging system and provides positive bending force for the optical imaging system, so that the focal length of the first lens is reasonably configured, the aberration of the optical imaging system is favorably corrected, the resolution of the system is improved, and the sensitivity of the system is reduced.

According to some embodiments of the invention, the effective focal length of the optical lens group is EFL, and the combined focal length of the second lens and the third lens is f₂₃Wherein, the EFL, f₂₃Satisfies the following conditions: -6 < f₂₃The EFL is less than 0. Thus, by constrainingThe combined focal length of the two lenses and the third lens and the effective focal length of the optical lens group can effectively balance the spherical aberration and distortion of the optical imaging system, and are favorable for correcting the image surface curvature, reducing the assembly sensitivity and improving the system resolving power.

According to some embodiments of the invention, the effective focal length of the optical lens group is EFL, and the combined focal length of the fourth lens and the fifth lens is f₄₅Wherein, the EFL, f₄₅Satisfies the following conditions: -3.6 < f₄₅The EFL is less than 0. Whereby by making-3.6 < f₄₅the/EFL is less than 0, the aberration of the optical lens group can be effectively balanced, the correction of field curvature is facilitated, the assembly sensitivity is reduced, and the system resolving power is improved, so that the imaging quality of the whole optical imaging system is improved.

According to some embodiments of the present invention, the air separation distance between the sixth lens and the seventh lens on the optical axis is CT₆A focal length f of the sixth lens₆A focal length f of the seventh lens₇Wherein, the CT₆、f₆、f₇Satisfies the following conditions: 1 < CT₆/(1/f₆+1/f₇) Is less than 25. Thus, by making 1 < CT₆/(1/f₆+1/f₇) And less than 25, the sixth lens and the seventh lens provide positive bending force for the system, which is beneficial to correcting system aberration, improving system resolving power and reducing sensitivity. Moreover, the arrangement can reasonably control the air space of the sixth lens and the seventh lens on the optical axis, so that the optical imaging system can meet the requirement of high pixel and realize miniaturization design.

According to some embodiments of the invention, the effective focal length of the optical lens group is EFL, and the focal length of the eighth lens is f₈Wherein, the EFL, f₈Satisfies the following conditions: -3 < f₈The EFL is less than 0. Therefore, since the eighth lens element is the last lens element from the object side to the image side of the optical imaging system and provides negative bending force for the optical imaging system, the imaging capability of the optical lens assembly can be enhanced for correcting the aberration of the optical imaging system and reducing the temperature sensitivity, and f₈The larger the absolute value is, the more the amount of change in back focus due to temperature isThe smaller the size is, the better the defocusing phenomenon caused by temperature difference can be avoided, the imaging quality is improved, and the picture is clearer.

According to some embodiments of the present invention, the effective focal length of the optical lens group is EFL, the entrance pupil diameter of the optical imaging system is EPD, wherein EFL, EPD satisfy: EFL/EPD < 1.7. Therefore, the smaller the f-number is, the larger the light flux amount is, the larger the depth of field is, so that the image sense of the optical imaging system is favorably increased, the presentation capability of details is enhanced, a long-distance object can be captured, and imaging is clearer.

According to some embodiments of the present invention, an air separation distance between an image side surface of the third lens element and an object side surface of the fourth lens element on an optical axis is ∑ CT₅₆The total length of the optical imaging system is TTL, wherein the ∑ CT is₅₆TTL satisfies 0 < ∑ CT₅₆TTL is less than 0.3. Therefore, the total length of the optical imaging system can be effectively shortened by controlling the air interval between the third lens and the fourth lens, the aberration can be corrected, and the resolving power of the optical imaging system is improved.

According to some embodiments of the present invention, the effective focal length of the optical lens group is EFL, the maximum field angle of the optical imaging system is FOV, the image height corresponding to the maximum field angle of the optical imaging system is Imgh, wherein EFL, FOV, Imgh satisfy: 45 (FOV multiplied by EFL)/Imgh is less than or equal to 70. So set up, be favorable to controlling the incident angle of light, rectify the aberration, lifting system resolving power guarantees that optical imaging system has under the prerequisite of high pixel, will shoot angle and the reasonable setting of field of view, makes optical imaging system can be used to long focus image device.

According to some embodiments of the invention, the object side of the eighth lens element has a radius of curvature R at the optical axis₁₃A focal length f of the eighth lens₈Wherein, said R₁₃、f₈Satisfies the following conditions: r is more than 0₁₃/f₈Is less than 1. Thus, by making 0 < R₁₃/f₈< 1, it is advantageous to control the degree of curvature of the eighth lens for correcting aberration, further reducing the generation ratio of ghost.

According to some embodiments of the present invention, the curvature radius of the image side surface of the fifth lens element at the optical axis is R₅The curvature radius of the object side surface of the sixth lens at the optical axis is R₆Wherein, said R₅、R₆Satisfies the following conditions: -7 < (R)₅+R₆)/(R₅-R₆) < -3 >. Thus, by making-7 < (R)₅+R₆)/(R₅-R₆) And < -3 >, the optical imaging system has a large visual angle and high definition at the same time, and the imaging quality is ensured.

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

According to the utility model discloses get for instance device through adopting above-mentioned optical imaging system, can satisfy long focus and high pixel simultaneously, and imaging quality is higher, 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: the shell is provided with a through hole; get for instance the device, get for instance the device for the instance according to the utility model discloses above-mentioned second aspect embodiment get for instance the device, get for instance the device and install through-hole department.

According to the utility model discloses electronic device gets for instance the device through adopting the aforesaid, makes electronic device have long focus and high pixel's advantage concurrently, fully provided user 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 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 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 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 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 graph of spherical aberration, astigmatism and distortion for the optical imaging system shown in fig. 9.

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 fifth lens; 6: a sixth lens; 7: a seventh lens;

8: an eighth lens; 9: a diaphragm; 10: an optical filter; 11: and (4) protecting the glass.

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. 1-10.

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

Specifically, the optical lens group includes a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a fifth lens 5, a sixth lens 6, a seventh lens 7, and an eighth lens 8, which are arranged in this order in the axial direction. The first lens 1, the second lens 2, the fifth lens 5, the sixth lens 6, and the seventh lens 7 each have a positive refracting power, and the third lens 3, the fourth lens 4, and the eighth lens 8 each have a negative refracting power.

It should be noted that the bending force refers to that the propagation direction of the light ray is deflected when the parallel light passes through the optical imaging system, and is used for representing the bending capability of the optical imaging system to the incident parallel light beam. The optical imaging system has positive bending force, which shows that the bending of light is convergent; the optical imaging system has a negative bending force, indicating that the bending of the light rays is divergent. In the optical imaging system 100 provided by the present invention, if the bending force or the focal length of the lens does not define its region position, the bending force or the focal length of the lens is the bending force or the focal length of the lens at the optical axis.

According to the utility model discloses optical imaging system 100, through making first lens 1, second lens 2, fifth lens 5, sixth lens 6 and seventh lens 7 all have positive refracting power, make optical imaging system 100 have sufficient ability of assembling, make optical imaging system 100's compact structure, avoid optical lens group's total length overlength. Through making third lens 3, fourth lens 4 and eighth lens 8 all have negative refracting power, make the light at big visual angle can get into optical imaging system 100, simultaneously, through carrying out corresponding optimization setting to first lens 1 to eighth lens 8, make optical lens group's configuration more reasonable, when making optical imaging system 100 satisfy long focal length, be favorable to realizing optical lens group's high pixelation, improved optical imaging system 100's imaging quality.

In some embodiments of the present invention, referring to fig. 1, 3, 5, 7 and 9, the object-side surface of the second lens element 2 is convex at the optical axis, the image-side surface of the second lens element 2 is concave at the optical axis, the object-side surface of the third lens element 3 is convex at the optical axis, the image-side surface of the third lens element 3 is concave at the optical axis, and the second lens element 2 and the third lens element 3 are cemented to each other. For example, in the examples of fig. 1, 3, 5, 7, and 9, the second lens 2 and the third lens 3 are cemented with each other to form a cemented structure, and the cemented structure has a meniscus shape, and the cemented surface is convex to the object side of the optical imaging system 100. Therefore, the optical imaging system 100 is compact by mutually bonding the second lens 2 and the third lens 3, which is advantageous for realizing a compact design and is balanced in terms of reducing the size and improving the system resolution. Moreover, the object side surfaces of the second lens element 2 and the third lens element 3 are convex and the image side surfaces are concave, which is beneficial to correcting the curvature of image plane, reducing the assembly sensitivity and improving the system resolution.

In some embodiments of the present invention, with reference to fig. 1, 3, 5, 7 and 9, the object-side surface and the image-side surface of the fourth lens element 4 are both concave surfaces at the optical axis, the object-side surface and the image-side surface of the fifth lens element 5 are both convex surfaces at the optical axis, and the fourth lens element 4 and the fifth lens element 5 are cemented to each other. Thus, by mutually cementing the fourth lens 4 and the fifth lens 5, the structure of the optical imaging system 100 can be made more compact, and a miniaturized design can be achieved. Further, the object-side surface of the fourth lens element 4 is concave on the optical axis, which is advantageous for correcting astigmatism.

In some embodiments of the present invention, referring to fig. 1, fig. 3, fig. 5, fig. 7 and fig. 9, the object-side surface of the first lens element 1 is a convex surface on the optical axis, the image-side surface of the first lens element 1 is a concave surface on the optical axis, the object-side surface and the image-side surface of the sixth lens element 6 are convex surfaces on the optical axis, the object-side surface of the seventh lens element 7 is a convex surface on the optical axis, the image-side surface of the seventh lens element 7 is a plane or a concave surface on the optical axis, the object-side surface of the eighth lens element 8 is a concave surface on the optical axis, and the image-side surface of the eighth lens element 8 is a. This arrangement can enlarge the angle of view by making the object-side surface of the first lens 1 convex on the optical axis and making the first lens 1 have positive refractive power. Moreover, the image side surface of the first lens 1 is concave at the optical axis, which is beneficial for the peripheral light rays with larger visual angle to enter the optical lens group, thereby enlarging the shooting range.

Alternatively, referring to fig. 1, one of the object-side surface and the image-side surface of the sixth lens 6 may be an aspheric surface. For example, in the example of fig. 1, the object-side surface of the sixth lens element 6 is aspheric, and the image-side surface of the sixth lens element 6 is spherical. So set up, be favorable to obtaining more control variable and subtract the aberration, promote system's resolving power, make the system formation of image more clear. Of course, both the object-side surface and the image-side surface of the sixth lens element 6 may be spherical. It is understood that the specific shape of the sixth lens 6 can be specifically set according to actual requirements to better meet the actual application.

In some optional embodiments of the present invention, the object-side surface or the image-side surface of one of the first lens element 1 to the eighth lens element 8 is provided with a filter (not shown). For example, the filter film may be an IR (Infrared) film, which can filter out Infrared light and transmit visible light. Therefore, the filter film is arranged on the surface of the lens, so that the image plane color balance can be kept more favorably, the photographing effect is close to that of human eyes, and the imaging quality of the optical imaging system 100 can be improved.

Of course, the present invention is not limited thereto, and in other optional embodiments of the present invention, the optical filter 10 is disposed between the image side of the eighth lens element 8 and the imaging plane. For example, the filter 10 may be an IR sheet. Therefore, the optical filter 10 is arranged on the image side of the eighth lens 8, and the optical filter 10 can also filter out light rays which are not needed in nature, so that the photographing effect is close to that of human eyes, the imaging effect of the optical imaging system 100 is ensured, and the optical filter 10 is independently arranged, which is beneficial to the assembly process of the optical lens group.

In some embodiments of the present invention, the effective focal length of the optical lens assembly is EFL, and the focal length of the first lens 1 is f₁Wherein EFL, f₁Satisfies the following conditions: f is more than 0₁The EFL is less than 2. Therefore, since the first lens element 1 is the first lens element from the object side to the image side of the optical imaging system 100 and provides a positive bending force for the optical imaging system 100, the focal length of the first lens element 1 is reasonably configured, which is beneficial to correcting the aberration of the optical imaging system 100, improving the system resolution and reducing the system sensitivity.

In some embodiments of the present invention, the optical lens groupHas an effective focal length of EFL and a combined focal length of the second lens 2 and the third lens 3 of f₂₃Wherein EFL, f₂₃Satisfies the following conditions: -6 < f₂₃The EFL is less than 0. For example, in the examples of fig. 1, 3, 5, 7, and 9, the second lens 2 and the third lens 3 are cemented to form a first cemented lens having a meniscus shape with a cemented surface convex to the object side of the optical imaging system 100, wherein the first cemented lens has a focal length f₂₃. Therefore, by constraining the combined focal length of the second lens 2 and the third lens 3 and the effective focal length of the optical lens group, the spherical aberration and distortion of the optical imaging system 100 can be effectively balanced, and the correction of the image surface curvature is facilitated, the assembly sensitivity is reduced, and the system resolving power is improved.

In some embodiments of the present invention, the effective focal length of the optical lens assembly is EFL, and the resultant focal length of the fourth lens 4 and the fifth lens 5 is f₄₅Wherein EFL, f₄₅Satisfies the following conditions: -3.6 < f₄₅The EFL is less than 0. For example, in the examples of fig. 1, 3, 5, 7, and 9, the fourth lens 4 and the fifth lens 5 are cemented with each other to form a second cemented lens, the cemented surface of which is convex toward the object side of the optical imaging system 100, and the focal length f of the second cemented lens is₄₅. Whereby by making-3.6 < f₄₅the/EFL is less than 0, so that the aberration of the optical lens group can be effectively balanced, the correction of field curvature is facilitated, the assembly sensitivity is reduced, and the system resolving power is improved, thereby improving the imaging quality of the whole optical imaging system 100.

In some embodiments of the present invention, the air separation distance between the sixth lens element 6 and the seventh lens element 7 on the optical axis is CT₆The focal length of the sixth lens 6 is f₆The focal length of the seventh lens 7 is f₇Wherein, CT₆、f₆、f₇Satisfies the following conditions: 1 < CT₆/(1/f₆+1/f₇) Is less than 25. Thus, by making 1 < CT₆/(1/f₆+1/f₇) And less than 25, the sixth lens 6 and the seventh lens 7 provide positive bending force for the system, which is beneficial to correcting system aberration, improving system resolving power and reducing sensitivity. Furthermore, the air space between the sixth lens 6 and the seventh lens 7 on the optical axis can be reasonably controlled by the arrangement, so that the optical system can be controlledThe imaging system 100 achieves a miniaturized design while satisfying a high pixel.

In some embodiments of the present invention, the effective focal length of the optical lens assembly is EFL, and the focal length of the eighth lens 8 is f₈Wherein EFL, f₈Satisfies the following conditions: -3 < f₈The EFL is less than 0. Therefore, since the eighth lens element 8 is the last lens element from the object side to the image side of the optical imaging system 100 and provides the optical imaging system 100 with negative bending force, the imaging capability of the optical lens assembly can be enhanced for correcting the aberration of the optical imaging system 100 and reducing the temperature sensitivity, and f₈The larger the absolute value is, the smaller the back focus variable quantity caused by the temperature is, which is beneficial to avoiding the defocusing phenomenon caused by the temperature difference, and improving the imaging quality to make the picture clearer.

In some embodiments of the present invention, the effective focal length of the optical lens group is EFL, and the entrance pupil diameter of the optical imaging system 100 is EPD, wherein EFL, EPD satisfy: EFL/EPD < 1.7. Therefore, the smaller the f-number, the larger the amount of light passing, and the larger the depth of field, so the arrangement is favorable for increasing the picture sense of the optical imaging system 100, enhancing the presenting capability of details, capturing a long-distance object and making the imaging clearer.

In some embodiments of the present invention, the air distance between the image-side surface of the third lens element 3 and the object-side surface of the fourth lens element 4 on the optical axis is ∑ CT₅₆The total length of the optical imaging system 100 is TTL, wherein ∑ CT₅₆TTL satisfies 0 < ∑ CT₅₆TTL is less than 0.3. Thus, by controlling the air space between the third lens element 3 and the fourth lens element 4 on the optical axis, the total length of the optical imaging system 100 can be effectively shortened, and the aberration can be corrected, thereby improving the resolution of the optical imaging system 100.

In some embodiments of the present invention, the effective focal length of the optical lens group is EFL, the maximum field angle of the optical imaging system 100 is FOV, the image height corresponding to the maximum field angle of the optical imaging system 100 is Imgh, wherein EFL, FOV, Imgh satisfy: 45 (FOV multiplied by EFL)/Imgh is less than or equal to 70. Note that "the maximum angle of view of the optical imaging system 100" refers to the angle of view in the diagonal direction of the optical imaging system 100. So set up, be favorable to controlling the incident angle of light, rectify the aberration, lifting system resolving power guarantees that optical imaging system 100 has under the prerequisite of high pixel, will shoot angle and the reasonable setting of field of view, makes optical imaging system 100 can be used to long focus imaging device.

In some embodiments of the present invention, the object side of the eighth lens element 8 has a radius of curvature R at the optical axis₁₃The focal length of the eighth lens 8 is f₈Wherein R is₁₃、f₈Satisfies the following conditions: r is more than 0₁₃/f₈Is less than 1. Thus, by making 0 < R₁₃/f₈< 1, it is advantageous to control the degree of curvature of the eighth lens 8 for correcting aberrations, further reducing the ratio of generation of ghost images.

In some embodiments of the present invention, the curvature radius of the image side surface of the fifth lens element 5 at the optical axis is R₅The curvature radius of the object-side surface of the sixth lens element 6 at the optical axis is R₆Wherein R is₅、R₆Satisfies the following conditions: -7 < (R)₅+R₆)/(R₅-R₆) < -3 >. Specifically, for example, when (R)₅+R₆)/(R₅-R₆) When the angle is less than or equal to-7, the angle of the principal ray incident image plane of the peripheral visual angle is easy to reduce; when (R)₅+R₆)/(R₅-R₆) When the amount is more than or equal to-3, the occurrence of astigmatism is easily suppressed. Thus, by making-7 < (R)₅+R₆)/(R₅-R₆) < -3 >, the optical imaging system 100 has a large viewing angle and high definition at the same time, and the imaging quality is ensured.

In a further embodiment of the present invention, as shown in fig. 1, fig. 3, fig. 5, fig. 7 and fig. 9, the optical lens group further includes a diaphragm 9, and the diaphragm 9 is disposed between the first lens 1 and the eighth lens 8. Therefore, by arranging the diaphragm 9, the influence of stray light on the image can be eliminated, and the quality of the image is improved. Moreover, the diaphragm 9 helps to reasonably control the field angle of the optical imaging system 100, so that the system can image more clearly.

Alternatively, the first lens 1, the second lens 2, the third lens 3, the fourth lens 4, the fifth lens 5, the sixth lens 6, the seventh lens 7, and the eighth lens 8 may be made of plastic, glass, or the like. When the first lens 1, the second lens 2, the third lens 3, the fourth lens 4, the fifth lens 5, the sixth lens 6, the seventh lens 7 and the eighth lens 8 are made of plastic, the weight of the optical imaging system 100 can be reduced and the production cost can be reduced; when the first lens element 1, the second lens element 2, the third lens element 3, the fourth lens element 4, the fifth lens element 5, the sixth lens element 6, the seventh lens element 7 and the eighth lens element 8 are made of glass, the optical imaging system 100 has excellent optical performance and high temperature resistance. Of course, the materials of the first lens 1, the second lens 2, the third lens 3, the fourth lens 4, the fifth lens 5, the sixth lens 6, the seventh lens 7, and the eighth lens 8 may be any combination of glass and plastic, and are not necessarily all glass or all plastic.

An optical imaging system 100 according to various embodiments of the present invention is described below with reference to fig. 1-10.

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 second lens 2, a third lens 3, a diaphragm 9, a fourth lens 4, a fifth lens 5, a sixth lens 6, a seventh lens 7, and an eighth lens 8, and the spherical aberration, astigmatism, and distortion curves of the optical imaging system 100 refer to fig. 2.

The object side surface and the image side surface of the first lens 1 to the eighth lens 8 do not have inflection points, the first lens 1 to the eighth lens 8 are made of glass, the second lens 2 and the third lens 3 are mutually glued, and the fourth lens 4 and the fifth lens 5 are mutually glued. The first lens element 1 has positive refractive power, the object-side surface of the first lens element 1 is a convex surface, the image-side surface of the first lens element 1 is a concave surface, and both the object-side surface and the image-side surface of the first lens element 1 are spherical surfaces. The second lens element 2 has positive refractive power, the object-side surface of the second lens element 2 is convex, the image-side surface of the second lens element 2 is concave, and both the object-side surface and the image-side surface of the second lens element 2 are spherical. The third lens element 3 has negative refractive power, the object-side surface of the third lens element 3 is a convex surface, the image-side surface of the third lens element 3 is a concave surface, and both the object-side surface and the image-side surface of the third lens element 3 are spherical surfaces. The fourth lens element 4 has negative bending force, both the object-side surface and the image-side surface of the fourth lens element 4 are concave surfaces, and both the object-side surface and the image-side surface of the fourth lens element 4 are spherical surfaces. The fifth lens element 5 has positive refractive power, both the object-side surface and the image-side surface of the fifth lens element 5 are convex surfaces, and both the object-side surface and the image-side surface of the fifth lens element 5 are spherical surfaces. The sixth lens element 6 has positive refractive power, both the object-side surface and the image-side surface of the sixth lens element 6 are convex surfaces, the object-side surface of the sixth lens element 6 is aspheric, and the image-side surface of the sixth lens element 6 is spherical. The seventh lens element 7 has positive refractive power, the object-side surface of the seventh lens element 7 is a convex surface, the image-side surface of the seventh lens element 7 is a flat surface, and both the object-side surface and the image-side surface of the seventh lens element 7 are spherical surfaces. The eighth lens element 8 has negative refractive power, the object-side surface of the eighth lens element 8 is a concave surface, the image-side surface of the eighth lens element 8 is a convex surface, and both the object-side surface and the image-side surface of the eighth lens element 8 are spherical surfaces.

The image plane is established at the image side of eighth lens 8, is equipped with IR piece and protective glass 11 between eighth lens 8 and the image plane in proper order, and the material of IR piece is glass and does not influence the focus, and photosensitive element sets up on the image plane. The IR film can filter imaging light entering the lens and filter infrared light.

Detailed optical data of the first embodiment is shown in table 1, aspheric coefficients thereof are shown in table 2, a unit of a radius of curvature, a thickness and a focal length is mm, and a reference wavelength of the optical imaging system 100 is 546.074 nm. Wherein, the aspheric surface formula is:

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

TABLE 1

TABLE 2

In the first embodiment, the effective focal length of the optical lens assembly is EFL, and the focal length of the first lens 1 is f₁The combined focal length of the second lens 2 and the third lens 3 is f₂₃The focal length of the fourth lens 4 and the focal length of the fifth lens 5 are f₄₅，f₁/EFL＝1.58；f₂₃/EFL＝-3.87，f₄₅-3.36,/EFL; the air gap distance between the sixth lens 6 and the seventh lens 7 is CT₆The focal length of the sixth lens 6 is f₆The focal length of the seventh lens 7 is f₇，CT₆/(1/f₆+1/f₇) 1.47; the eighth lens element 8 has a focal length f₈，f₈The optical imaging system 100 has an entrance pupil diameter EPD of-2.39, the optical imaging system 100 has an entrance pupil diameter EPD of 1.65, and the distance between the image-side surface of the third lens 3 and the object-side surface of the fourth lens 4 on the optical axis is ∑ CT₅₆The total length of the optical imaging system 100 is TTL, &lTtT translation = Sigma "&gTt &lTt/T &gTt CT₅₆0.18, FOV (maximum field of view) of the optical imaging system 100, Imgh (FOV × EFL)/56.363, and R (radius of curvature) of the object-side surface of the eighth lens element 8 on the optical axis₁₃，R₁₃/f₈0.58; the curvature radius of the image side surface of the fifth lens 5 at the optical axis is R₅The curvature radius of the object-side surface of the sixth lens element 6 at the optical axis is R₆，(R₅+R₆)/(R₅-R₆)＝-5.31。

Thus, with the above arrangement, the optical imaging system 100 can satisfy high definition shooting while achieving a long focal length, and is advantageous for achieving a miniaturized design.

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 object side surface of the sixth lens element 6 is spherical, the image side surface of the eighth lens element 8 is concave, and only the protective glass 11 is disposed between the eighth lens element 8 and the image plane, without an IR plate.

Detailed optical data for example two as shown in table 3, the radius of curvature, thickness and focal length are in millimeters and the reference wavelength of the optical imaging system 100 is 546.074 nm.

TABLE 3

In example two, f₁/EFL＝1.47，f₂₃/EFL＝-3.15，f₄₅/EFL＝-2.10，CT₆/(1/f₆+1/f₇)＝1.05，f₈/EFL＝-1.19，EFL/EPD＝1.65，∑CT₅₆/TTL＝0.19，(FOV×EFL)/Imgh＝56.683，R₁₃/f₈＝0.79，(R₅+R₆)/(R₅-R₆)＝-6.42。

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 second embodiment, wherein the same reference numerals are used for the same components, except that: the image-side surface of the seventh lens element 7 is concave, and the image-side surface of the eighth lens element 8 is convex.

Detailed optical data for example three are shown in table 4, where the radius of curvature, thickness and focal length are in millimeters and the reference wavelength of the optical imaging system 100 is 546.074 nm.

TABLE 4

In factIn example III, f₁/EFL＝1.71，f₂₃/EFL＝-5.32，f₄₅/EFL＝-2.73，CT₆/(1/f₆+1/f₇)＝6.16，f₈/EFL＝-1.35，EFL/EPD＝1.65，∑CT₅₆/TTL＝0.20，(FOV×EFL)/Imgh＝56.512，R₁₃/f₈＝0.63，(R₅+R₆)/(R₅-R₆)＝-5.49。

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

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 third embodiment, wherein the same reference numerals are used for the same components, except that: the radii of curvature of the object-side and image-side surfaces of the first to seventh lenses 1 to 7 and the object-side surface of the eighth lens 8 are different from those of the third embodiment.

Detailed optical data for example four as shown in table 5, the radius of curvature, thickness and focal length are in millimeters and the reference wavelength of the optical imaging system 100 is 546.074 nm.

TABLE 5

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 fourth embodiment, wherein the same reference numerals are used for the same components, except that: the image-side surface of the eighth lens element 8 is concave.

Detailed optical data for example five as shown in table 6, the radius of curvature, thickness and focal length are in millimeters and the reference wavelength of the optical imaging system 100 is 546.074 nm.

TABLE 6

In example five, f₁/EFL＝1.76，f₂₃/EFL＝-5.3，f₄₅/EFL＝-2.55，CT₆/(1/f₆+1/f₇)＝9.8，f₈/EFL＝-1.03，EFL/EPD＝1.65，∑CT₅₆/TTL＝0.17，(FOV×EFL)/Imgh＝56.614，R₁₃/f₈＝0.93，(R₅+R₆)/(R₅-R₆)＝-4.73。

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

An image capturing device (not shown) according to an embodiment of the present invention includes an optical imaging system 100 and a photosensitive element. Specifically, the optical imaging system 100 is the optical imaging system 100 according to the above-described first aspect of the present invention, and the photosensitive element is disposed on the image side of the optical imaging system 100.

According to the utility model discloses get for instance device through adopting above-mentioned optical imaging system 100, can satisfy long focus and high pixel simultaneously, and imaging quality is higher, 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. Be formed with the through-hole on the casing, get for instance the device for the sake of the utility model discloses the device for getting for the sake of the above-mentioned second aspect embodiment is installed in through-hole department for getting for the sake of the device.

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, a fourth lens, a fifth lens, a sixth lens, a seventh lens and an eighth lens which are sequentially arranged along the axial direction;

the first lens, the second lens, the fifth lens, the sixth lens, and the seventh lens each have a positive refracting power;

the third lens, the fourth lens, and the eighth lens each have a negative bending force.

2. The optical imaging system of claim 1, wherein the object-side surface of the second lens element is convex, the image-side surface of the second lens element is concave, the object-side surface of the third lens element is convex, the image-side surface of the third lens element is concave, and the second and third lens elements are cemented to each other.

3. The optical imaging system of claim 1, wherein the fourth lens element has a concave object-side surface and a concave image-side surface at the optical axis, wherein the fifth lens element has a convex object-side surface and a convex image-side surface at the optical axis, and wherein the fourth lens element and the fifth lens element are cemented to each other.

4. The optical imaging system of claim 1, wherein an object-side surface of the first lens element is convex at an optical axis, an image-side surface of the first lens element is concave at the optical axis, both the object-side surface and the image-side surface of the sixth lens element are convex at the optical axis, an object-side surface of the seventh lens element is convex at the optical axis, an image-side surface of the seventh lens element is flat or concave at the optical axis, an object-side surface of the eighth lens element is concave at the optical axis, and an image-side surface of the eighth lens element is convex or concave at the optical axis.

5. The optical imaging system of any one of claims 1 to 4, wherein an object side surface or an image side surface of one of the first to eighth lenses is provided with a filter; or

And a filter is arranged between the image side and the imaging surface of the eighth lens.

6. The optical imaging system of claim 1, wherein the effective focal length of the optical lens group is EFL and the focal length of the first lens is f₁Wherein, the EFL, f₁Satisfies the following conditions:

0＜f₁/EFL＜2。

7. the optical imaging system of claim 1, wherein the effective focal length of the optical lens group is EFL, and the combined focal length of the second lens and the third lens is f₂₃Wherein, the EFL, f₂₃Satisfies the following conditions:

-6＜f₂₃/EFL＜0。

8. the optical imaging system of claim 1, wherein the effective focal length of the optical lens group is EFL, and the combined focal length of the fourth lens and the fifth lens is f₄₅Wherein, the EFL, f₄₅Satisfies the following conditions:

-3.6＜f₄₅/EFL＜0。

9. the optical imaging system of claim 1, wherein the sixth lens and the seventh lens are spaced apart from each other by a distance CT on an optical axis₆A focal length f of the sixth lens₆A focal length f of the seventh lens₇Wherein, the CT₆、f₆、f₇Satisfies the following conditions:

1＜CT₆/(1/f₆+1/f₇)＜25。

10. the optical imaging system of claim 1, wherein the effective focal length of the optical lens group is EFL and the focal length of the eighth lens is f₈Wherein, the EFL, f₈Satisfies the following conditions:

-3＜f₈/EFL＜0。

11. the optical imaging system of claim 1, wherein the effective focal length of the optical lens group is EFL and the entrance pupil diameter of the optical imaging system is EPD, wherein the EFL, EPD satisfies:

EFL/EPD＜1.7。

12. the optical imaging system of claim 1, wherein the spatial separation distance on the optical axis between the image-side surface of the third lens and the object-side surface of the fourth lens is ∑ CT₅₆The total length of the optical imaging system is TTL, wherein the ∑ CT is₅₆And TTL satisfies:

0＜∑CT₅₆/TTL＜0.3。

13. the optical imaging system of claim 1, wherein the effective focal length of the optical lens group is EFL, the maximum field of view of the optical imaging system is FOV, and the image height corresponding to the maximum field of view of the optical imaging system is Imgh, wherein the EFL, the FOV, and the Imgh satisfy:

45≤(FOV×EFL)/Imgh≤70。

14. the optical imaging system of claim 1, wherein a radius of curvature of an object-side surface of the eighth lens at an optical axis is R₁₃A focal length f of the eighth lens₈Wherein, said R₁₃、f₈Satisfies the following conditions:

0＜R₁₃/f₈＜1。

15. the optical imaging system of claim 1, wherein the radius of curvature of the image-side surface of the fifth lens at the optical axis is R₅The curvature radius of the object side surface of the sixth lens at the optical axis is R₆Wherein, said R₅、R₆Satisfies the following conditions:

-7＜(R₅+R₆)/(R₅-R₆)＜-3。

16. an image capturing apparatus, comprising:

an optical imaging system according to any one of claims 1-15;

the photosensitive element is arranged on the image side of the optical imaging system.

17. An electronic device, comprising:

the shell is provided with a through hole;

an image capturing device according to claim 16, the image capturing device being mounted at the through hole.