CN215416068U

CN215416068U - Optical system, image capturing module and electronic equipment

Info

Publication number: CN215416068U
Application number: CN202121086563.9U
Authority: CN
Inventors: 粘明德
Original assignee: Jiangxi Jinghao Optical Co Ltd
Current assignee: Jiangxi Jinghao Optical Co Ltd
Priority date: 2021-05-20
Filing date: 2021-05-20
Publication date: 2022-01-04
Anticipated expiration: 2031-05-20

Abstract

The utility model relates to an optical system, an image capturing module and an electronic device. The optical system comprises a first lens element with positive refractive power, and an object-side surface of the first lens element is convex at a paraxial region; a second lens element with negative refractive power having a convex object-side surface and a concave image-side surface; a third lens element with positive refractive power having a convex object-side surface and a concave image-side surface; the steering prism assembly can change the direction of a light path by 180 degrees, so that an image plane and an object plane of the optical system are positioned on the same side of the steering prism assembly; the 367 < f > 43/(2 > ImgH) is < 425; f is the effective focal length of the optical system, and ImgH is half the image height corresponding to the maximum field angle of the optical system. The optical system can realize the ultra-long focal length characteristic.

Description

Optical system, image capturing module and electronic equipment

Technical Field

The present invention relates to the field of camera shooting, and in particular, to an optical system, an image capturing module and an electronic device.

Background

With the development of the camera technology, more and more electronic devices such as smart phones, tablet computers, and notebook computers are equipped with camera lenses to achieve the image capturing function. The shooting requirements of users on the electronic equipment are higher and higher, and the electronic equipment is required to realize the effects of background blurring, remote shooting and the like so as to improve the user experience. However, the current optical system has insufficient focal length, and it is difficult to achieve background blurring and telephoto effects.

SUMMERY OF THE UTILITY MODEL

Accordingly, it is desirable to provide an optical system, an image capturing module and an electronic device for solving the problem of insufficient focal length of the optical system.

An optical system includes, in order from an object side to an image side along an optical axis:

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

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

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

and the optical system satisfies the following conditional expression:

367≤f*43/(2*ImgH)≤425；

wherein f is the effective focal length of the optical system, and ImgH is half of the image height corresponding to the maximum field angle of the optical system.

In the optical system, the first lens element has positive refractive power, which is beneficial to shortening the total length of the optical system. The second lens element with negative refractive power can effectively correct aberration generated by the first lens element, and is favorable for correcting chromatic aberration of the optical system. The object side surface of the second lens element is convex at the optical axis, and the image side surface of the second lens element is concave at the optical axis, which facilitates further correction of aberration generated by the first lens element and reasonable control of refractive power of the second lens element, thereby reducing sensitivity of the optical system. The third lens element with positive refractive power can effectively share the refractive power of the first lens element, thereby reducing the sensitivity of the optical system. The object side surface of the third lens is a convex surface at the optical axis, and the image side surface of the third lens is a concave surface at the optical axis, so that astigmatism and high-order aberration of the optical system can be corrected.

When the condition formula is met, the optical system can realize the super-long-focus characteristic, so that effects of background blurring, long-distance shooting and the like can be realized, and the requirements of more scene shooting can be met. Exceeding the upper limit of the above conditional expressions makes the total length of the optical system too long, which is not favorable for the realization of a miniaturized design. Below the lower limit of the above conditional expression, the optical system has difficulty in realizing the ultra-long focal length characteristic.

Above-mentioned optical system sets up and turns to prism subassembly, changes 180 with the trend of light path, is favorable to reducing optical system at the perpendicular and be on a parallel with the size in two directions of the primary optical axis of third lens to be favorable to the realization of miniaturized design, make super long focus optical system can be applied to among the miniaturized electronic equipment.

In one embodiment, the optical system satisfies the following conditional expression:

19≤TTL/ImgH≤24；

wherein TTL is a distance on an optical axis from an object-side surface of the first lens element to an image plane of the optical system, that is, a total optical length of the optical system. The ratio of the total optical length to the half-image height of the optical system can be reasonably configured by satisfying the conditional expression, and the total optical length of the optical system can be favorably shortened while good imaging quality is ensured, so that the realization of miniaturization design is favorably realized.

1.1≤TTL/f≤1.2；

wherein, TTL is a distance on an optical axis from an object-side surface of the first lens element to an image plane of the optical system. The ratio of the total optical length to the effective focal length of the optical system can be reasonably configured by satisfying the conditional expression, and the optical system is favorable for realizing the super-long focal length characteristic while realizing the miniaturization design.

-1≤f1/f23≤-0.5；

wherein f1 is the effective focal length of the first lens, and f23 is the combined focal length of the second lens and the third lens. The condition is satisfied, the overall refractive power of the first lens, the second lens and the third lens is favorably and reasonably distributed, so that the chromatic aberration of the optical system is favorably corrected, and the imaging quality of the optical system is improved.

0.9≤map2/map1≤1；

the map2 is the radius of the maximum light-passing area of the marginal ray of the maximum field of view in the vertical optical axis direction when the marginal ray of the maximum field of view passes through the image side of the third lens, and the map1 is the radius of the maximum light-passing area of the marginal ray of the central field of view in the vertical optical axis direction when the marginal ray of the central field of view passes through the image side of the third lens. Satisfying above-mentioned conditional expression is favorable to promoting optical system's relative luminance to make optical system also can possess good image quality under the low light environment.

28mm≤ImgH/tan(HFOV)≤34mm；

wherein the HFOV is half of a maximum field angle of the optical system. Satisfying above-mentioned conditional expression, being favorable to the realization of optical system super long focal characteristic to when optical system is applied to among the electronic equipment, can cooperate with other optical systems among the electronic equipment, and then be favorable to increasing optical system's magnification, satisfy more shooting demands.

8≤TTL/CT23≤15；

wherein, TTL is an axial distance from an object-side surface of the first lens element to an image plane of the optical system, and CT23 is an axial distance from an object-side surface of the second lens element to an image-side surface of the third lens element. The position arrangement of the second lens and the third lens can be more compact when the condition formula is satisfied, so that the second lens and the third lens can be integrally a transition part of light deflection in the optical system, and the refractive power integrally distributed by the second lens and the third lens can be reduced, and the sensitivity of the optical system can be reduced.

0.8≤(R2+R1)/(R2-R1)≤1.4；

wherein R2 is a curvature radius of an image side surface of the first lens at an optical axis, and R1 is a curvature radius of an object side surface of the first lens at the optical axis. The first lens can be reasonably configured according to the condition, so that the first-order aberration of the optical system can be effectively corrected by the first lens, and the imaging quality of the optical system is improved.

In one embodiment, the optical system further includes a turning prism assembly disposed on the image side of the third lens, and the turning prism assembly is capable of changing the direction of the optical path by 180 ° so that the image plane and the object plane of the optical system are located on the same side of the turning prism assembly.

In one embodiment, the turning prism assembly comprises a right-angle prism and a pentaprism in sequence from the object side to the image side along the optical axis;

the right-angle prism comprises a first surface and a second surface which are perpendicular to each other, the first surface is perpendicular to the main optical axis of the third lens, and light rays can be emitted from the second surface after entering the right-angle prism from the first surface;

the pentaprism comprises a third surface and a fourth surface which are perpendicular to each other, the third surface is parallel to the second surface, and light rays emitted from the second surface can enter the pentaprism from the third surface and exit from the fourth surface. The right-angle prism and the pentaprism are matched, so that the light path can be effectively turned to 180 degrees, the size of the optical system in two directions perpendicular to and parallel to the main optical axis of the third lens is reduced, the miniaturization design is facilitated, and the ultra-long-focus optical system can be applied to the miniaturized electronic equipment.

An image capturing module includes a photosensitive element and the optical system of any of the above embodiments, wherein the photosensitive element is disposed at an image side of the optical system. Adopt above-mentioned optical system in getting for instance the module, can realize the super long focus characteristic to be favorable to realizing effects such as background blurring, long-distance shooting, simultaneously, set up and turn to prism subassembly, be favorable to reducing and get for instance the module at the perpendicular and be on a parallel with the two dimensions of the principal axis of third lens, make and get for instance the module and can not too big in these two dimensions of orientation, thereby be favorable to getting for instance the application of module in miniaturized electronic equipment.

An electronic device comprises a shell and the image capturing module, wherein the image capturing module is arranged on the shell. Adopt above-mentioned module of getting for instance among the electronic equipment, can realize super long focus characteristic to be favorable to realizing effects such as background blurring, long-distance shooting, simultaneously, set up and turn to prism subassembly, be favorable to reducing and get for instance the size of module in two directions of the principal optical axis of perpendicular and being on a parallel with the third lens, make and get for instance the size of module in these two directions can not too big, thereby be favorable to electronic equipment's miniaturized design.

Drawings

FIG. 1 is a schematic structural diagram of an optical system according to a first embodiment of the present application;

FIG. 2 is a longitudinal spherical aberration diagram, an astigmatism diagram and a distortion diagram of an optical system in a first embodiment of the present application;

FIG. 3 is a schematic structural diagram of an optical system according to a second embodiment of the present application;

FIG. 4 is a longitudinal spherical aberration diagram, an astigmatism diagram and a distortion diagram of an optical system in a second embodiment of the present application;

FIG. 5 is a schematic structural diagram of an optical system according to a third embodiment of the present application;

FIG. 6 is a longitudinal spherical aberration diagram, an astigmatism diagram and a distortion diagram of an optical system in a third embodiment of the present application;

FIG. 7 is a schematic structural diagram of an optical system according to a fourth embodiment of the present application;

FIG. 8 is a longitudinal spherical aberration diagram, an astigmatism diagram and a distortion diagram of an optical system in a fourth embodiment of the present application;

FIG. 9 is a schematic structural diagram of an optical system according to a fifth embodiment of the present application;

FIG. 10 is a longitudinal spherical aberration diagram, an astigmatism diagram and a distortion diagram of an optical system in a fifth embodiment of the present application;

fig. 11 is a schematic view of an image capturing module according to an embodiment of the present application;

fig. 12 is a schematic diagram of an electronic device in an embodiment of the present application.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the utility model and to simplify the description, and are not intended to indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and are not to be considered limiting of the utility model.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like as used herein are for illustrative purposes only and do not denote a unique embodiment.

In some embodiments of the present disclosure, the optical system 100 includes, in order from an object side to an image side along an optical axis 110, a first lens L1, a second lens L2, and a third lens L3. Specifically, the first lens L1 includes an object-side surface S1 and an image-side surface S2, the second lens L2 includes an object-side surface S3 and an image-side surface S4, and the third lens L3 includes an object-side surface S5 and an image-side surface S6.

The first lens element L1 with positive refractive power is advantageous for shortening the total length of the optical system 100. The object-side surface S1 of the first lens element L1 is convex at the paraxial region 110. The second lens element L2 with negative refractive power can effectively correct the aberration generated by the first lens element L1, and is favorable for correcting the chromatic aberration of the optical system 100. The object-side surface S3 of the second lens element L2 is convex along the optical axis 110, and the image-side surface S4 is concave along the optical axis 110, which is favorable for further correcting the aberration generated by the first lens element L1 and reasonably controlling the refractive power of the second lens element L2, thereby reducing the sensitivity of the optical system 100. The third lens element L3 with positive refractive power can effectively share the refractive power of the first lens element L1, thereby reducing the sensitivity of the optical system 100. The object-side surface S5 of the third lens element L3 is convex at the optical axis 110, and the image-side surface S6 is concave at the optical axis 110, which is favorable for correcting astigmatism and high-order aberration of the optical system 100.

In addition, in some embodiments, the optical system 100 is provided with a stop STO, which may be disposed between the first lens L1 and the second lens. In some embodiments, the optical system 100 further includes an infrared filter LL6 disposed on the image side of the third lens L3, and the infrared filter L6 includes an object-side surface S14 and an image-side surface S15. Furthermore, the optical system 100 further includes an image plane S16 located on the image side of the third lens L3, the image plane S16 is an imaging plane of the optical system 100, and the incident light is adjusted by the first lens L1, the second lens L2 and the third lens L3 and can be imaged on the image plane S16. It should be noted that the infrared filter L6 may be an infrared cut filter, and is used for filtering the interference light and preventing the interference light from reaching the image plane S16 of the optical system 100 to affect the normal imaging.

In some embodiments, the optical system 100 further includes a turning prism assembly, and the turning prism assembly is capable of changing the direction of the optical path by 180 °, so that the image plane S16 and the object plane of the optical system 100 are located on the same side of the turning prism assembly, in other words, the light exiting from the third lens L3 exits in the object-side direction to reach the image plane S16 after passing through the turning prism assembly. The arrangement of the steering prism assembly changes the trend of the light path by 180 degrees, the effect of folding the light path can be realized, the size of the optical system 100 in two directions of the main optical axis vertical to and parallel to the third lens L3 is favorably reduced, the miniaturization design is favorably realized, and the ultra-long-focus optical system 100 can be applied to the miniaturized electronic equipment.

Further, the number and type of prisms in the steering prism assembly are not limited as long as the direction of the optical path can be changed by 180 °. For example, in some embodiments, the steering prism assembly includes a right angle prism L4 and a pentaprism L5, and the right angle prism L4 and the pentaprism L5 can change the direction of the light path by 90 °, respectively. Specifically, the right-angle prism L4 includes, in order from the object side to the image side along the optical axis 110, a first surface S7, a first reflection surface S8, and a second surface S9, the first surface S7 is perpendicular to the main optical axis of the third lens L3, and the second surface S9 is perpendicular to the first surface S7. The light emitted from the third lens L3 can enter the right-angle prism L4 from the first surface S7, and is reflected by the first reflecting surface L8 and then exits from the second surface S9. Here, the light path of the outgoing light ray from the second surface S9 is changed by 90 ° with respect to the outgoing light ray from the third lens L3. The pentaprism L5 includes, in order from the object side to the image side along the optical axis 110, a third surface S10, a second reflective surface S11, a third reflective surface S12, and a fourth surface S13, the third surface S10 is parallel to the second surface S9 and opposite to the second surface S9, the fourth surface S13 is perpendicular to the third surface S10, the second reflective surface S11 connects the fourth surface S13, and the third reflective surface S12 connects the third surface S10. The light emitted from the right-angle prism L4 can enter the pentaprism from the third surface S10, and then exit from the fourth surface S13 after being reflected by the second reflecting surface S11 and the third reflecting surface S12 in sequence. At this time, the outgoing light ray of the fourth surface S13 changes the optical path routing by 90 ° with respect to the outgoing light ray of the second surface S9. It can be understood that the included angles between the first reflecting surface S8 and the first surface S7 and the second surface S9 are both 90 °, the sum of the included angle between the second reflecting surface S12 and the fourth surface S13 and the included angle between the third reflecting surface S12 and the third surface S10 is 270 °, and the orientation of the light path can be effectively changed by 180 ° by the cooperation of the triangular prism L4 and the pentaprism L5.

Of course, the turning prism assembly may also include other numbers of prisms, such as three, five, six prisms, and the prisms in the turning prism assembly may be all right-angle prisms or all pentaprisms, and in the embodiment shown in fig. 1, the arrangement order of the right-angle prisms L4 and the pentaprisms L5 may also be reversed. Other arrangements of the steering prism assembly are possible, as long as the optical path can be changed by 180 °, and are not described herein.

In some embodiments, the object-side surface and the image-side surface of each lens of optical system 100 are both aspheric. The adoption of the aspheric surface structure can improve the flexibility of lens design, effectively correct spherical aberration and improve imaging quality. In other embodiments, the object-side surface and the image-side surface of each lens of the optical system 100 may be spherical. It should be noted that the above embodiments are only examples of some embodiments of the present application, and in some embodiments, the surface of each lens in the optical system 100 may be an aspheric surface or any combination of spherical surfaces.

In some embodiments, each lens in the optical system 100 may be made of glass or plastic. The lens made of plastic material can reduce the weight of the optical system 100 and the production cost, and the light and thin design of the optical system 100 can be realized by matching with the small size of the optical system 100. The glass lens provides the optical system 100 with excellent optical performance and high temperature resistance. It should be noted that the material of each lens in the optical system 100 may be any combination of glass and plastic, and is not necessarily both glass and plastic.

It is to be noted that the first lens L1 does not mean that there is only one lens, and in some embodiments, there may be two or more lenses in the first lens L1, and the two or more lenses can form a cemented lens, and a surface of the cemented lens closest to the object side can be regarded as the object side surface S1, and a surface of the cemented lens closest to the image side can be regarded as the image side surface S2. Alternatively, although no cemented lens is formed between the lenses of the first lens L1, the distance between the lenses is relatively fixed, and in this case, the object-side surface of the lens closest to the object side is the object-side surface S1, and the image-side surface of the lens closest to the image side is the image-side surface S2. In addition, the number of lenses in the second lens L2 or the third lens L3 in some embodiments may be greater than or equal to two, and a cemented lens may be formed between any two adjacent lenses, or may be a non-cemented lens.

Further, in some embodiments, the optical system 100 satisfies the conditional expression: 367 is less than or equal to f 43/(2 is less than or equal to ImgH) is less than or equal to 425; where f is the effective focal length of the optical system 100, and ImgH is half the image height corresponding to the maximum field angle of the optical system 100. Specifically, f × 43/(2 × ImgH) may be: 367.871, 379.654, 388.157, 394.625, 401.324, 415.966, 420.524, 430.247, 435.125, or 441.363. When the above conditional expressions are satisfied, the optical system 100 can realize an ultra-long focus characteristic, thereby being beneficial to realizing effects of background blurring, long-distance shooting and the like, and satisfying the requirements of shooting in more scenes. Exceeding the upper limit of the above conditional expression makes the total length of the optical system 100 too long, which is disadvantageous for realizing a compact design. Below the lower limit of the above conditional expression, it is difficult for the optical system 100 to realize the ultra-long focal length characteristic.

In some embodiments, the optical system 100 satisfies the conditional expression: TTL/ImgH is more than or equal to 19 and less than or equal to 24; wherein, TTL is a distance from the object-side surface S1 of the first lens element L1 to the image plane of the optical system 100 on the optical axis 110. Specifically, TTL/ImgH may be: 19.943, 19.995, 20.013, 20.285, 20.394, 21.554, 21.764, 21.934, 22.552, or 23.601. Satisfying the above conditional expressions, the ratio of the total optical length and the half-image height of the optical system 100 can be configured reasonably, and the total optical length of the optical system 100 can be shortened while good imaging quality is ensured, thereby facilitating realization of miniaturization design.

In some embodiments, the optical system 100 satisfies the conditional expression: TTL/f is more than or equal to 1.1 and less than or equal to 1.2; wherein, TTL is a distance from the object-side surface S1 of the first lens element L1 to the image plane of the optical system 100 on the optical axis 110. Specifically, TTL/f may be: 1.150, 1.152, 1.153, 1.155, 1.156, 1.159, 1.161, 1.162, 1.164, or 1.166. Satisfying the above conditional expressions, the ratio of the total optical length and the effective focal length of the optical system 100 can be configured reasonably, and the optical system 100 is facilitated to realize the super-long focal length characteristic while realizing the miniaturization design.

In some embodiments, the optical system 100 satisfies the conditional expression: f1/f23 is more than or equal to-1 and less than or equal to-0.5; wherein f1 is the effective focal length of the first lens L1, and f23 is the combined focal length of the second lens L2 and the third lens L3. Specifically, f1/f23 may be: -0.876, -0.866, -0.851, -0.832, -0.801, -0.765, -0.732, -0.722, -0.719 or-0.713. Satisfying the above conditional expressions is beneficial to reasonably distributing the refractive power of the first lens element L1, the second lens element L2 and the third lens element L3, thereby being beneficial to correcting the chromatic aberration of the optical system 100 and improving the imaging quality of the optical system 100.

In some embodiments, the optical system 100 satisfies the conditional expression: map2/map1 is more than or equal to 0.9 and less than or equal to 1; here, map2 is the radius of the maximum light-passing region in the direction perpendicular to the optical axis 110 when the marginal ray of the maximum field of view passes through the image-side surface S6 of the third lens L3, and map1 is the radius of the maximum light-passing region in the direction perpendicular to the optical axis 110 when the marginal ray of the central field of view passes through the image-side surface S6 of the third lens L3. To facilitate understanding of the concepts of map1 and map2, fig. 1 schematically illustrates the dimensions of map1 and map2 in the optical system 100 of the first embodiment. Specifically, map2/map1 may be: 0.917, 0.919, 0.920, 0.926, 0.929, 0.935, 0.937, 0.940, 0.941 or 0.942. Satisfying the above conditional expression is beneficial to improving the relative brightness of the optical system 100, so that the optical system 100 can have good imaging quality even in a low light environment.

In some embodiments, the optical system 100 satisfies the conditional expression: the FOV is 8.9 ≦ FOV ≦ 10.8, where the FOV is the maximum field angle of the optical system 100, in other words, the FOV defines the maximum field of view of the optical system 100. Specifically, the FOV may be: 8.92, 9.26, 9.45, 9.62, 9.88, 10.01, 10.22, 10.55, 10.61 or 10.70, the numerical units being.

It should be noted that in some embodiments, the optical system 100 may match a photosensitive element having a rectangular photosensitive surface, and the imaging surface of the optical system 100 coincides with the photosensitive surface of the photosensitive element. At this time, the effective pixel area on the imaging plane of the optical system 100 has a horizontal direction and a diagonal direction, ImgH may be understood as a half of the length of the effective pixel area on the imaging plane of the optical system 100 in the diagonal direction, and FOV may be understood as the maximum field angle of the optical system 100 in the diagonal direction.

In some embodiments, the optical system 100 satisfies the conditional expression: FNO is not less than 4.4 and not more than 5.1, wherein FNO is the f-number of the optical system. Specifically, FNO may be: 4.40, 4.41, 4.48, 4.52, 4.59, 4.67, 4.86, 4.88, 4.90 or 5.00. Satisfying the above relationship is advantageous for increasing the light flux of the optical system 100 while achieving the super-telephoto characteristic of the optical system 100, so that the optical system 100 can have good imaging quality even when shooting under low-light conditions.

In some embodiments, the optical system 100 satisfies the conditional expression: imgH/tan (HFOV) is less than or equal to 28mm and less than or equal to 34 mm; the HFOV is half of the maximum field angle of the optical system 100. Specifically, ImgH/tan (hfov) may be: 28.084, 28.564, 28.974, 29.321, 29.554, 29.673, 31.024, 31.587, 32.623 or 33.718, the numerical units being in mm. Satisfying above-mentioned conditional expression, being favorable to the realization of optical system 100 super long focal length characteristic to when optical system 100 is applied to electronic equipment, can cooperate with other optical systems in electronic equipment, and then be favorable to increasing optical system 100's magnification, satisfy more shooting demands.

In some embodiments, the optical system 100 satisfies the conditional expression: TTL/CT23 is more than or equal to 8 and less than or equal to 15; wherein, TTL is a distance from the object-side surface S1 of the first lens element L1 to the image plane of the optical system 100 on the optical axis 110, and CT23 is a distance from the object-side surface S3 of the second lens element L2 to the image-side surface S6 of the third lens element L3 on the optical axis 110. Specifically, TTL/CT23 may be: 8.184, 8.561, 8.937, 9.654, 10.325, 10.789, 12.154, 13.038, 13.896, or 14.244. Satisfying the above conditional expressions, the position arrangement of the second lens element L2 and the third lens element L3 can be more compact, so that the second lens element L2 and the third lens element L3 can be a transition portion of light ray deflection in the optical system 100 as a whole, and the refractive power distributed by the second lens element L2 and the third lens element L3 as a whole can be reduced, thereby reducing the sensitivity of the optical system 100.

In some embodiments, the optical system 100 satisfies the conditional expression: (R2+ R1)/(R2-R1) is not more than 0.8 and not more than 1.4; wherein R2 is the radius of curvature of the image-side surface S2 of the first lens element L1 along the optical axis 110, and R1 is the radius of curvature of the object-side surface S1 of the first lens element L1 along the optical axis 110. Specifically, (R2+ R1)/(R2-R1) may be: 0.838, 0.874, 1.021, 1.084, 1.134, 1.157, 1.205, 1.284, 1.327, or 1.360. Satisfying the above conditional expressions, the surface shape of the first lens L1 can be reasonably configured, so that the first lens L1 can effectively correct the first-order aberration of the optical system 100, and the imaging quality of the optical system 100 is improved.

The reference wavelengths of the above effective focal length values are all 555 nm.

Based on the above description of the embodiments, more specific embodiments and drawings are set forth below for detailed description.

First embodiment

Referring to fig. 1 and fig. 2, fig. 1 is a schematic structural diagram of an optical system 100 in the first embodiment, in which the optical system 100 includes, in order from an object side to an image side, a first lens element L1 with positive refractive power, a stop STO, a second lens element L2 with negative refractive power, a third lens element L3 with positive refractive power, a triangular prism L4, and a pentaprism L5. Fig. 2 is a graph of longitudinal spherical aberration, astigmatism and distortion of the optical system 100 in the first embodiment, sequentially from left to right, wherein the reference wavelength of the astigmatism graph and the distortion graph is 555nm, and the other embodiments are the same.

The object-side surface S1 of the first lens element L1 is convex at the paraxial region 110, and the image-side surface S2 is concave at the paraxial region 110;

the object-side surface S3 of the second lens element L2 is convex at the paraxial region 110, and the image-side surface S4 is concave at the paraxial region 110;

the object-side surface S5 of the third lens element L3 is convex at the paraxial region 110, and the image-side surface S6 is concave at the paraxial region 110.

The object-side and image-side surfaces of the first lens L1, the second lens L2, and the third lens L3 are aspheric.

The first lens L1, the second lens L2 and the third lens L3 are all made of plastic.

Further, the optical system 100 satisfies the conditional expression: f 43/(2 ImgH) ═ 367.871; where f is the effective focal length of the optical system 100, and ImgH is half the image height corresponding to the maximum field angle of the optical system 100. When the above conditional expressions are satisfied, the optical system 100 can realize an ultra-long focus characteristic, thereby being beneficial to realizing effects of background blurring, long-distance shooting and the like, and satisfying the requirements of shooting in more scenes. Exceeding the upper limit of the above conditional expression makes the total length of the optical system 100 too long, which is disadvantageous for realizing a compact design. Below the lower limit of the above conditional expression, it is difficult for the optical system 100 to realize the ultra-long focal length characteristic.

The optical system 100 satisfies the conditional expression: TTL/ImgH 19.943; wherein, TTL is a distance from the object-side surface S1 of the first lens element L1 to the image plane of the optical system 100 on the optical axis 110. Satisfying the above conditional expressions, the ratio of the total optical length and the half-image height of the optical system 100 can be configured reasonably, and the total optical length of the optical system 100 can be shortened while good imaging quality is ensured, thereby facilitating realization of miniaturization design.

The optical system 100 satisfies the conditional expression: TTL/f is 1.166; wherein, TTL is a distance from the object-side surface S1 of the first lens element L1 to the image plane of the optical system 100 on the optical axis 110. Satisfying the above conditional expressions, the ratio of the total optical length and the effective focal length of the optical system 100 can be configured reasonably, and the optical system 100 is facilitated to realize the super-long focal length characteristic while realizing the miniaturization design.

The optical system 100 satisfies the conditional expression: f1/f23 is-0.876; wherein f1 is the effective focal length of the first lens L1, and f23 is the combined focal length of the second lens L2 and the third lens L3. Satisfying the above conditional expressions is beneficial to reasonably distributing the refractive power of the first lens element L1, the second lens element L2 and the third lens element L3, thereby being beneficial to correcting the chromatic aberration of the optical system 100 and improving the imaging quality of the optical system 100.

The optical system 100 satisfies the conditional expression: map2/map1 is 0.942; here, map2 is the radius of the maximum light-passing region in the direction perpendicular to the optical axis 110 when the marginal ray of the maximum field of view passes through the image-side surface S6 of the third lens L3, and map1 is the radius of the maximum light-passing region in the direction perpendicular to the optical axis 110 when the marginal ray of the central field of view passes through the image-side surface S6 of the third lens L3. Satisfying the above conditional expression is beneficial to improving the relative brightness of the optical system 100, so that the optical system 100 can have good imaging quality even in a low light environment.

The optical system 100 satisfies the conditional expression: FNO 4.40, where FNO is the f-number of the optical system. Satisfying the above relationship is advantageous for increasing the light flux of the optical system 100 while achieving the super-telephoto characteristic of the optical system 100, so that the optical system 100 can have good imaging quality even when shooting under low-light conditions.

The optical system 100 satisfies the conditional expression: ImgH/tan (hfov) ═ 28.084 mm; the HFOV is half of the maximum field angle of the optical system 100. Satisfying above-mentioned conditional expression, being favorable to the realization of optical system 100 super long focal length characteristic to when optical system 100 is applied to electronic equipment, can cooperate with other optical systems in electronic equipment, and then be favorable to increasing optical system 100's magnification, satisfy more shooting demands.

The optical system 100 satisfies the conditional expression: TTL/CT23 is 8.184; wherein, TTL is a distance from the object-side surface S1 of the first lens element L1 to the image plane of the optical system 100 on the optical axis 110, and CT23 is a distance from the object-side surface S3 of the second lens element L2 to the image-side surface S6 of the third lens element L3 on the optical axis 110. Satisfying the above conditional expressions, the position arrangement of the second lens element L2 and the third lens element L3 can be more compact, so that the second lens element L2 and the third lens element L3 can be a transition portion of light ray deflection in the optical system 100 as a whole, and the refractive power distributed by the second lens element L2 and the third lens element L3 as a whole can be reduced, thereby reducing the sensitivity of the optical system 100.

The optical system 100 satisfies the conditional expression: (R2+ R1)/(R2-R1) ═ 1.150; wherein R2 is the radius of curvature of the image-side surface S2 of the first lens element L1 along the optical axis 110, and R1 is the radius of curvature of the object-side surface S1 of the first lens element L1 along the optical axis 110. Satisfying the above conditional expressions, the surface shape of the first lens L1 can be reasonably configured, so that the first lens L1 can effectively correct the first-order aberration of the optical system 100, and the imaging quality of the optical system 100 is improved.

In addition, the parameters of the optical system 100 are given in table 1. Among them, the image plane S16 in table 1 may be understood as an imaging plane of the optical system 100. The elements from the object plane (not shown) to the image plane S16 are sequentially arranged in the order of the elements from top to bottom in table 1. The Y radius in table 1 is the radius of curvature of the object-side or image-side surface at the optical axis 110 for the corresponding surface number. Surface numbers S1 and S2 denote an object-side surface S1 and an image-side surface S2 of the first lens L1, respectively, that is, in the same lens, a surface with a smaller surface number is an object-side surface, and a surface with a larger surface number is an image-side surface. The first numerical value in the "thickness" parameter column of the first lens element L1 is the thickness of the lens element along the optical axis 110, and the second numerical value is the distance between the image-side surface and the rear surface of the lens element along the image-side direction along the optical axis 110.

Note that, in this embodiment and the following embodiments, the optical system 100 may not be provided with the infrared filter L6, but the distance from the image-side surface S6 of the third lens L3 to the image surface S16 is kept constant at this time.

In the first embodiment, the effective focal length f of the optical system 100 is 45mm, and the total optical length TTL of 5.35 ° of the half HFOV of the maximum field angle is 52.45 mm.

And the reference wavelengths of the focal length, the refractive index and the Abbe number of each lens are 555nm, and the other embodiments are also the same.

TABLE 1

Further, aspheric coefficients of the image-side surface or the object-side surface of each lens of the optical system 100 are given by table 2. Wherein, the surface numbers from S1 to S6 represent the image side or the object side S1 to S6, respectively. And K-a20 from left to right respectively represent the type of aspheric coefficients, where K represents a conic coefficient, a4 represents a quartic aspheric coefficient, a6 represents a sextic aspheric coefficient, A8 represents an octal aspheric coefficient, and so on. In addition, the aspherical surface coefficient formula is as follows:

where 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 110, c is the curvature of the aspheric surface vertex, k is the conic coefficient, and Ai is the coefficient corresponding to the i-th high order term in the aspheric surface profile formula.

TABLE 2

In addition, fig. 2 includes a Longitudinal Spherical Aberration diagram (Longitudinal Spherical Aberration) of the optical system 100, which shows the deviation of the converging focal points of the light rays of different wavelengths after passing through the lens. The ordinate of the longitudinal spherical aberration diagram represents the Normalized Pupil coordinate (Normalized Pupil Coordinator) from the Pupil center to the Pupil edge, and the abscissa represents the distance (in mm) of the imaging plane from the intersection of the ray with the optical axis 110. It can be known from the longitudinal spherical aberration diagram that the convergent focus deviation degrees of the light rays with different wavelengths in the first embodiment tend to be consistent, and the diffuse speckle or the chromatic halo in the imaging picture is effectively suppressed. FIG. 2 also includes a field curvature diagram (ASTIGMATIC FIELD CURVES) of optical system 100, where the S-curve represents sagittal field curvature at 555nm and the T-curve represents meridional field curvature at 555 nm. As can be seen from the figure, the curvature of field of the optical system 100 is small, the curvature of field and astigmatism of each field are well corrected, and the center and the edge of the field have clear images. Fig. 2 also includes a DISTORTION map (distorsion) of the optical system 100, and it can be seen that the image DISTORTION caused by the main beam is small and the imaging quality of the system is excellent.

Second embodiment

Referring to fig. 3 and 4, fig. 3 is a schematic structural diagram of the optical system 100 in the second embodiment, in which the optical system 100 includes, in order from an object side to an image side, a first lens element L1 with positive refractive power, a stop STO, a second lens element L2 with negative refractive power, a third lens element L3 with positive refractive power, a triangular prism L4 and a pentaprism L5. Fig. 4 is a graph of longitudinal spherical aberration, astigmatism and distortion of the optical system 100 in the second embodiment, which is shown from left to right.

In addition, the parameters of the optical system 100 are given in table 3, and the definitions of the parameters can be obtained from the first embodiment, which is not described herein.

TABLE 3

Further, the aspheric coefficients of the image-side surface or the object-side surface of each lens of the optical system 100 are shown in table 4, and the definitions of the parameters can be obtained from the first embodiment, which is not repeated herein.

TABLE 4

Number of noodles

S1

S2

S3

S4

S5

S6

K

1.465E-01

7.901E+00

5.660E+00

-5.850E+00

-4.636E+00

-1.417E+00

A4

6.506E-06

5.634E-05

7.493E-04

1.155E-03

4.334E-04

1.602E-04

A6

-3.036E-07

-3.959E-07

-1.092E-05

-6.014E-06

-2.698E-06

-3.195E-06

A8

2.575E-09

-3.480E-09

0.000E+00

7.850E-08

8.911E-08

A10

0.000E+00

A12

0.000E+00

A14

0.000E+00

A16

0.000E+00

A18

0.000E+00

A20

0.000E+00

According to the provided parameter information, the following data can be deduced:

f43/(2ImgH)	384.221	map2/map1	0.939
				TTL/ImgH	20.551	ImgH/tan(HFOV)	29.411mm
TTL/f	1.150	TTL/CT23	9.137
				f1/f23	-0.842	(R2+R1)/(R2-R1)	1.360

in addition, as can be seen from the aberration diagram in fig. 4, the longitudinal spherical aberration, curvature of field, and distortion of the optical system 100 are well controlled, so that the optical system 100 of this embodiment has good imaging quality.

Third embodiment

Referring to fig. 5 and 6, fig. 5 is a schematic structural diagram of the optical system 100 in the third embodiment, in which the optical system 100 includes, in order from an object side to an image side, a first lens element L1 with positive refractive power, a stop STO, a second lens element L2 with negative refractive power, a third lens element L3 with positive refractive power, a triangular prism L4 and a pentaprism L5. Fig. 6 is a graph of longitudinal spherical aberration, astigmatism and distortion of the optical system 100 in the third embodiment, from left to right.

In addition, the parameters of the optical system 100 are given in table 5, and the definitions of the parameters can be obtained from the first embodiment, which is not described herein again.

TABLE 5

Further, the aspheric coefficients of the image-side surface or the object-side surface of each lens of the optical system 100 are shown in table 6, and the definitions of the parameters can be obtained from the first embodiment, which is not repeated herein.

TABLE 6

Number of noodles

S1

S2

S3

S4

S5

S6

K

-4.554E-02

9.900E+01

-9.900E+01

-4.895E+00

-3.678E+00

-9.240E+00

A4

-4.024E-06

4.688E-05

5.349E-04

1.143E-03

1.022E-03

1.032E-03

A6

1.647E-07

1.104E-06

-7.379E-06

-1.696E-05

-1.583E-05

-1.695E-05

A8

3.490E-09

-9.282E-09

0.000E+00

7.572E-08

1.474E-07

A10

0.000E+00

A12

0.000E+00

A14

0.000E+00

A16

0.000E+00

A18

0.000E+00

A20

0.000E+00

f43/(2ImgH)	408.500	map2/map1	0.938
				TTL/ImgH	21.912	ImgH/tan(HFOV)	31.254mm
TTL/f	1.153	TTL/CT23	14.244
				f1/f23	-0.778	(R2+R1)/(R2-R1)	1.060

in addition, as can be seen from the aberration diagram in fig. 6, the longitudinal spherical aberration, curvature of field, and distortion of the optical system 100 are well controlled, so that the optical system 100 of this embodiment has good imaging quality.

Fourth embodiment

Referring to fig. 7 and 8, fig. 7 is a schematic structural diagram of the optical system 100 in the fourth embodiment, in which the optical system 100 includes, in order from an object side to an image side, a first lens element L1 with positive refractive power, a stop STO, a second lens element L2 with negative refractive power, a third lens element L3 with positive refractive power, a triangular prism L4 and a pentaprism L5. Fig. 8 is a graph of longitudinal spherical aberration, astigmatism and distortion of the optical system 100 in the fourth embodiment, which is shown from left to right.

The object-side surface S1 of the first lens element L1 is convex at the paraxial region 110, and the image-side surface S2 is convex at the paraxial region 110;

In addition, the parameters of the optical system 100 are given in table 7, and the definitions of the parameters can be obtained from the first embodiment, which is not described herein.

TABLE 7

Further, the aspheric coefficients of the image-side surface or the object-side surface of each lens of the optical system 100 are shown in table 8, and the definitions of the parameters can be obtained from the first embodiment, which is not repeated herein.

TABLE 8

Number of noodles

S1

S2

S3

S4

S5

S6

K

1.306E+00

-9.900E+01

-4.006E+01

-3.373E+00

-5.287E+00

-9.900E+01

A4

-5.071E-06

1.738E-04

-2.394E-05

7.718E-04

9.257E-04

5.819E-04

A6

1.163E-06

2.687E-07

1.990E-06

-1.677E-05

-1.336E-05

-1.119E-05

A8

-8.362E-09

-6.941E-09

0.000E+00

-3.945E-07

-1.106E-07

A10

0.000E+00

A12

0.000E+00

A14

0.000E+00

A16

0.000E+00

A18

0.000E+00

A20

0.000E+00

f43/(2ImgH)	424.850	map2/map1	0.918
				TTL/ImgH	22.988	ImgH/tan(HFOV)	32.475mm
TTL/f	1.163	TTL/CT23	11.702
				f1/f23	-0.713	(R2+R1)/(R2-R1)	0.838

in addition, as can be seen from the aberration diagram in fig. 8, the longitudinal spherical aberration, curvature of field, and distortion of the optical system 100 are well controlled, so that the optical system 100 of this embodiment has good imaging quality.

Fifth embodiment

Referring to fig. 9 and 10, fig. 9 is a schematic structural diagram of the optical system 100 in the fifth embodiment, in which the optical system 100 includes, in order from an object side to an image side, a first lens element L1 with positive refractive power, a stop STO, a second lens element L2 with negative refractive power, a third lens element L3 with positive refractive power, a triangular prism L4 and a pentaprism L5. Fig. 10 is a graph showing the longitudinal spherical aberration, astigmatism and distortion of the optical system 100 in the fifth embodiment from left to right.

In addition, the parameters of the optical system 100 are given in table 9, and the definitions of the parameters can be obtained from the first embodiment, which is not described herein.

TABLE 9

Further, the aspheric coefficients of the image-side surface or the object-side surface of each lens of the optical system 100 are shown in table 10, and the definitions of the parameters can be obtained from the first embodiment, which is not repeated herein.

Watch 10

f43/(2ImgH)	441.363	map2/map1	0.917
				TTL/ImgH	23.601	ImgH/tan(HFOV)	33.718mm
TTL/f	1.150	TTL/CT23	12.163
				f1/f23	-0.720	(R2+R1)/(R2-R1)	1.135

in addition, as can be seen from the aberration diagram in fig. 10, the longitudinal spherical aberration, curvature of field, and distortion of the optical system 100 are well controlled, so that the optical system 100 of this embodiment has good imaging quality.

Referring to fig. 11, in some embodiments, the optical system 100 may be assembled with the photosensitive element 210 to form the image capturing module 200. At this time, the light-sensing surface of the light-sensing element 210 may be regarded as the image surface S16 of the optical system 100. The image capturing module 200 may further include an infrared filter L6, and the infrared filter L6 is disposed between the image side surface S6 and the image surface S16 of the third lens element L3. Specifically, the photosensitive element 210 may be a Charge Coupled Device (CCD) or a Complementary Metal-Oxide Semiconductor (CMOS) Device. The optical system 100 is adopted in the image capturing module 200, so that the super-long-focus characteristic can be realized, and effects of background blurring, long-distance shooting and the like can be realized. Meanwhile, the arrangement of the triple prism L4 and the pentaprism L5 is beneficial to reducing the size of the image capturing module 200 in two directions perpendicular to and parallel to the main optical axis of the third lens L3, so that the size of the image capturing module 200 in the two directions is not too large, thereby being beneficial to the application of the image capturing module 200 in the miniaturized electronic device.

Referring to fig. 11 and 12, in some embodiments, the image capturing module 200 may be applied to an electronic device 300, the electronic device includes a housing 310, and the image capturing module 200 is disposed in the housing 310. Specifically, the electronic apparatus 300 may be, but is not limited to, a wearable device such as a mobile phone, a video phone, a smart phone, an electronic book reader, a vehicle-mounted image capturing apparatus such as a car recorder, or a smart watch. When the electronic device 300 is a smartphone, the housing 310 may be a middle frame of the electronic device 300. Adopt above-mentioned module 200 of getting for instance in electronic equipment 300, can realize the super long focus characteristic, thereby be favorable to realizing the background blurring, effects such as long-distance shooting, simultaneously, prism L4 and pentaprism L5's setting is favorable to reducing the size of getting for instance module 200 in perpendicular and the two directions of the primary optical axis that is on a parallel with third lens L3, make the size of getting for instance module 200 in these two directions all can not be too big, thereby be favorable to electronic equipment 300's miniaturized design.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the utility model. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

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

and the optical system satisfies the following conditional expression:

367≤f*43/(2*ImgH)≤425；

2. The optical system according to claim 1, wherein the following conditional expression is satisfied:

19≤TTL/ImgH≤24；

wherein, TTL is a distance on an optical axis from an object-side surface of the first lens element to an image plane of the optical system.

3. The optical system according to claim 1, wherein the following conditional expression is satisfied:

1.1≤TTL/f≤1.2；

4. The optical system according to claim 1, wherein the following conditional expression is satisfied:

-1≤f1/f23≤-0.5；

wherein f1 is the effective focal length of the first lens, and f23 is the combined focal length of the second lens and the third lens.

5. The optical system according to claim 1, wherein the following conditional expression is satisfied:

0.9≤map2/map1≤1；

the map2 is the radius of the maximum light-passing area of the marginal ray of the maximum field of view in the vertical optical axis direction when the marginal ray of the maximum field of view passes through the image side of the third lens, and the map1 is the radius of the maximum light-passing area of the marginal ray of the central field of view in the vertical optical axis direction when the marginal ray of the central field of view passes through the image side of the third lens.

6. The optical system according to claim 1, wherein the following conditional expression is satisfied:

28mm≤ImgH/tan(HFOV)≤34mm；

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

7. The optical system according to claim 1, wherein the following conditional expression is satisfied:

8≤TTL/CT23≤15；

wherein, TTL is an axial distance from an object-side surface of the first lens element to an image plane of the optical system, and CT23 is an axial distance from an object-side surface of the second lens element to an image-side surface of the third lens element.

8. The optical system according to claim 1, wherein the following conditional expression is satisfied:

0.8≤(R2+R1)/(R2-R1)≤1.4；

wherein R2 is a curvature radius of an image side surface of the first lens at an optical axis, and R1 is a curvature radius of an object side surface of the first lens at the optical axis.

9. The optical system of claim 1, further comprising a turning prism assembly disposed on the image side of the third lens, the turning prism assembly capable of changing the direction of the optical path by 180 ° such that the image plane and the object plane of the optical system are on the same side of the turning prism assembly.

10. The optical system of claim 9, wherein the turning prism assembly comprises a right-angle prism and a pentaprism in order from an object side to an image side along an optical axis;

the pentaprism comprises a third surface and a fourth surface which are perpendicular to each other, the third surface is parallel to the second surface, and light rays emitted from the second surface can enter the pentaprism from the third surface and exit from the fourth surface.

11. An image capturing module, comprising a photosensitive element and the optical system of any one of claims 1 to 10, wherein the photosensitive element is disposed on an image side of the optical system.

12. An electronic device, comprising a housing and the image capturing module of claim 11, wherein the image capturing module is disposed on the housing.