CN113900224B

CN113900224B - Optical system, image capturing module and electronic equipment

Info

Publication number: CN113900224B
Application number: CN202111123714.8A
Authority: CN
Inventors: 谭怡翔; 党绪文; 李明
Original assignee: Jiangxi Jingchao Optical Co Ltd
Current assignee: Jiangxi Jingchao Optical Co Ltd
Priority date: 2021-09-24
Filing date: 2021-09-24
Publication date: 2023-09-05
Anticipated expiration: 2041-09-24
Also published as: CN113900224A

Abstract

The invention relates to an optical system, an image capturing module and electronic equipment. The optical system includes: the first lens element with positive refractive power has a convex object-side surface at a paraxial region and a concave image-side surface at a paraxial region; the second lens element with refractive power has a convex object-side surface at a paraxial region and a concave image-side surface at a paraxial region; a third lens element with refractive power; the fourth lens element with positive refractive power has a convex object-side surface at a paraxial region and a concave image-side surface at a paraxial region; the fifth lens element with negative refractive power has a convex object-side surface at a paraxial region and a concave image-side surface at a paraxial region; the optical system satisfies: HFOV/FNO of 25 deg.ltoreq.HFOV/FNO of 33 deg.ltoreq.. The optical system has good imaging quality and large aperture characteristics.

Description

Optical system, image capturing module and electronic equipment

Technical Field

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

Background

With rapid development Of Time Of Flight (TOF) detection technology, TOF shots are increasingly used in electronic devices such as smartphones, tablet computers, and electronic readers, so that the requirements Of the industry on the imaging quality Of the TOF shots are also increasing. The aperture number of the TOF lens has great influence on imaging quality, and the large aperture characteristic can improve the imaging brightness of the TOF lens, so that the TOF lens can also have good imaging quality in a low-light environment. However, it is difficult for the current TOF lens to meet the requirement of a large aperture.

Disclosure of Invention

Based on this, it is necessary to provide an optical system, an image capturing module and an electronic device for the present TOF lens which is difficult to meet the requirement of a large aperture.

An optical system comprising, 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 a paraxial region and a concave image-side surface at a paraxial region;

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

a third lens element with refractive power;

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

a fifth lens element with negative refractive power having a convex object-side surface at a paraxial region and a concave image-side surface at a paraxial region;

and the optical system satisfies the following conditional expression:

25deg≤HFOV/FNO≤33deg；

wherein HFOV is half the maximum field angle of the optical system and FNO is the f-number of the optical system.

In the optical system, the first lens element with positive refractive power has a convex object-side surface at a paraxial region thereof, which is conducive to converging light rays and shortening the overall length of the optical system. The convex-concave surface type of the first lens is matched with the convex-concave surface type of the second lens to be favorable for preventing light from being too converged, so that the trend of the light is more gentle, the sensitivity of the optical system is reduced, and meanwhile, the chromatic aberration of the optical system is eliminated. The fourth lens element with positive refractive power is beneficial to correcting the incident angle of light beam expanded by the second lens element and the third lens element. The fifth lens element with negative refractive power has a convex object-side surface at a paraxial region and a concave image-side surface at a paraxial region, thereby being beneficial to correcting off-axis aberration and on-axis chromatic aberration and improving imaging quality of the optical system. The optical system has the refractive power and the surface shape, can realize miniaturized design and has high imaging quality.

When the above conditional expression is satisfied, the half field angle and the f-number of the optical system can be reasonably configured, so that the optical system can have the characteristics of a large field angle and a large aperture at the same time, and not only can the requirement of large-range shooting be satisfied, but also the requirement of large light flux of the TOF lens can be satisfied. Exceeding the upper limit of the above conditional expression, the angle of view and aperture of the optical system are too large, which is unfavorable for light control and thus unfavorable for improvement of imaging quality. Below the lower limit of the above conditional expression, the angle of view and aperture of the optical system are too small, which results in a reduction in the visual field, difficulty in meeting the requirement for large-scale shooting, and a dark angle phenomenon due to insufficient light flux.

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

1.1≤f/EPD≤1.4；

where f is the effective focal length of the optical system and EPD is the entrance pupil diameter of the optical system. The optical system has the characteristics of a large aperture, is favorable for obtaining enough light entering quantity, avoids dark angles around an imaging surface, and is favorable for improving the shooting effect of the optical system in a weak light environment; in addition, the increase of the aperture is also beneficial to shrinking the size of Ai Liban, so that the optical system has higher resolution limit, and the optical system can meet the design requirement of high pixels by matching with reasonable collocation of the refractive power of each lens in the optical system.

0.4≤SD11/ImgH≤0.6；

the SD11 is half of the maximum effective aperture of the object side surface of the first lens, and the ImgH is half of the image height corresponding to the maximum field angle of the optical system. When the condition is satisfied, the ratio of the maximum effective half caliber of the object side surface of the first lens to the half image height of the optical system can be reasonably configured, so that the step difference between the lenses in the optical system is reduced, the smooth transition of the whole optical system is facilitated, and in addition, the light flux of the optical system is improved, and the relative illumination of imaging is improved. Exceeding the upper limit of the above conditional expression, the maximum effective aperture of the object side surface of the first lens is too large, which results in difficulty in controlling incident light, and a longer structure is required to achieve smooth transition of light, thereby being unfavorable for miniaturization design of the optical system. And the lower limit of the conditional expression is lower than the lower limit of the conditional expression, and the maximum effective caliber of the object side surface of the first lens is too small, so that the light flux is reduced, the relative illuminance is difficult to reach a design value, and the requirement of the TOF lens for high imaging quality is difficult to meet.

1.6≤TTL/ImgH≤1.9；

The TTL is the distance between the object side surface of the first lens element and the imaging surface of the optical system on the optical axis, that is, the total optical length of the optical system, and ImgH is half of the image height corresponding to the maximum field angle of the optical system. When the above conditional expression is satisfied, the ratio of the total length of the optical system to the half image height can be reasonably configured, which is favorable for shortening the total length of the optical system, so that the optical system can realize miniaturized design. Exceeding the upper limit of the above conditional expression, the total length of the optical system is excessively large, which is not advantageous for the miniaturization design of the optical system. The total length of the optical system is too short below the lower limit of the conditional expression, so that the surface type of each lens is too bent, and high-order aberration is easy to generate, thereby increasing the sensitivity among the lenses, and being unfavorable for reaching the design specification of the product and improving the imaging performance.

2≤|f2/f1|≤17；

wherein f2 is the effective focal length of the second lens, and f1 is the effective focal length of the first lens. When the above conditional expression is satisfied, the ratio of the effective focal lengths of the first lens and the second lens can be reasonably configured, so that the refractive power of the second lens is not too close to that of the first lens, thereby being beneficial to smooth transition of light converged by the first lens to each lens in the image space through the second lens, and meanwhile being beneficial to chromatic aberration on each lens balance shaft of the image space of the second lens and correction of off-axis coma. Exceeding the upper limit of the above conditional expression, the refractive power of the second lens element is too small, which results in an increase in the burden of controlling light by each lens element on the image side, and thus, the surface shape of each lens element on the object side is excessively curved, which is unfavorable for improving the imaging quality of the optical system. Below the lower limit of the above conditional expression, the refractive powers of the second lens element and the first lens element are too close, so that light is too gathered, the light is not reasonably expanded, the burden of adjusting the light by each lens element in the image space is increased, and the improvement of the imaging quality is not facilitated.

0.1≤BF/TTL≤0.2；

wherein BF is the shortest distance between the image side surface of the fifth lens element and the imaging surface of the optical system in the optical axis direction, and TTL is the distance between the object side surface of the first lens element and the imaging surface of the optical system in the optical axis direction. When the above conditional expression is satisfied, the rear Jiao Zhanbi of the optical system can be reasonably configured, the total length of the optical system is shortened to realize miniaturized design, and meanwhile, the incident angle of the chief ray from the outermost view field to the imaging surface is reasonably controlled, so that the decline of the relative illuminance caused by the overlarge incident angle of the chief ray from the outermost view field is avoided, and the imaging quality of the optical system is improved.

0＜SAG42/SAG51≤3.4；

the SAG42 is a sagittal height of the image side surface of the fourth lens element at the maximum effective aperture, that is, a distance from an intersection point of the image side surface of the fourth lens element and the optical axis to the maximum effective aperture of the image side surface of the fourth lens element in the optical axis direction, and the SAG51 is a sagittal height of the object side surface of the fifth lens element at the maximum effective aperture, that is, a distance from an intersection point of the object side surface of the fifth lens element and the optical axis to the maximum effective aperture of the object side surface of the fifth lens element in the optical axis direction. When the above conditions are satisfied, the ratio of the image side sagittal height of the fourth lens to the object side sagittal height of the fifth lens can be reasonably configured, so that the image side of the fourth lens is matched with the shape of the object side of the fifth lens, thereby being beneficial to reducing the incidence angle of light rays between the fourth lens and the fifth lens on the lens surface, further being beneficial to inhibiting the generation of off-axis chromatic aberration, and simultaneously being beneficial to improving the luminous flux of the optical system.

1.3≤∑CT/∑AT≤2.6；

and Σct is the sum of thicknesses of the first lens, the second lens, the third lens, the fourth lens and the fifth lens on the optical axis, Σat is the sum of air intervals of two adjacent lenses of the first lens, the second lens, the third lens, the fourth lens and the fifth lens on the optical axis, namely the sum of air intervals of the first lens and the second lens, the second lens and the third lens, the third lens and the fourth lens and the fifth lens on the optical axis. When the above conditional expression is satisfied, the center thickness of each lens in the optical system and the distance between each adjacent lens can be reasonably configured, which is favorable for making the distribution of each lens more uniform, thereby being favorable for smooth transition of light in the optical system, further being favorable for eliminating higher-order aberration and improving the imaging quality of the optical system.

0.8≤f1/f34≤1.2；

wherein f1 is an effective focal length of the first lens, and f34 is a combined focal length of the third lens and the fourth lens. When the above conditional expression is satisfied, the ratio of the effective focal length of the first lens element to the combined focal length of the third lens element and the fourth lens element can be reasonably configured, so that the refractive power of the first lens element is close to the combined refractive power of the third lens element and the fourth lens element, and a similar symmetrical structure is formed between the first lens element and the combination of the third lens element and the fourth lens element, thereby being beneficial to correcting the aberration of the optical system and improving the imaging quality of the optical system.

An image capturing module includes a photosensitive element and the optical system according to any of the above embodiments, where the photosensitive element is disposed on an image side of the optical system. The optical system is adopted in the image capturing module, so that the imaging module has good imaging quality and large aperture characteristic, and the requirement of large light flux of the TOF lens can be met.

An electronic device comprises a shell and the image capturing module, wherein the image capturing module is arranged on the shell. The imaging module is adopted in the electronic equipment, and the imaging module has good imaging quality and large aperture characteristic, so that the application of the electronic equipment in the TOF detection field is facilitated.

Drawings

Fig. 1 is a schematic structural view of an optical system in a first embodiment of the present application;

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

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

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

fig. 5 is a schematic structural view of an optical system in a third embodiment of the present application;

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

fig. 7 is a schematic structural view of an optical system in a fourth embodiment of the present application;

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

fig. 9 is a schematic structural view of an optical system in a fifth embodiment of the present application;

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

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

fig. 12 is a schematic diagram of an electronic device according to an embodiment of the application.

Detailed Description

In order that the above objects, features and advantages of the application will be readily understood, a more particular description of the application will be rendered by reference to the appended drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. The present application may be embodied in many other forms than described herein and similarly modified by those skilled in the art without departing from the spirit of the application, whereby the application is not limited to the specific embodiments disclosed below.

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

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

In the present invention, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.

In the present invention, unless expressly stated or limited otherwise, a first feature "up" or "down" a second feature may be the first and second features in direct contact, or the first and second features in indirect contact via an intervening medium. Moreover, a first feature being "above," "over" and "on" a second feature may be a first feature being directly above or obliquely above the second feature, or simply indicating that the first feature is level higher than the second feature. The first feature being "under", "below" and "beneath" the second feature may be the first feature being directly under or obliquely below the second feature, or simply indicating that the first feature is less level than the second feature.

It will be understood that when an element is referred to as being "fixed" 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 are used herein for illustrative purposes only and are not meant to be the only embodiment.

Referring to fig. 1, in some embodiments of the present application, the optical system 100 includes a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, and a fifth lens L5 in order from an object side to an image side along an optical axis 110. Specifically, the first lens element L1 comprises an object-side surface S1 and an image-side surface S2, the second lens element L2 comprises an object-side surface S3 and an image-side surface S4, the third lens element L3 comprises an object-side surface S5 and an image-side surface S6, the fourth lens element L4 comprises an object-side surface S7 and an image-side surface S8, and the fifth lens element L5 comprises an object-side surface S9 and an image-side surface S10. The first lens L1, the second lens L2, the third lens L3, the fourth lens L4 and the fifth lens L5 are coaxially disposed, and a common axis of the lenses in the optical system 100 is an optical axis 110 of the optical system 100.

The first lens element L1 with positive refractive power has a convex object-side surface S1 at a paraxial region 110, which facilitates focusing of light beams and shortens an overall length of the optical system 100. The first lens element L1 has a convex object-side surface S1 at a paraxial region 110, a concave image-side surface S2 at the paraxial region 110, and a convex object-side surface S3 at the paraxial region 110, and a concave image-side surface S4 at the paraxial region 110. The convex-concave shape of the first lens L1 and the convex-concave shape of the second lens L2 are beneficial to preventing the light from being too converged, so that the trend of the light is more gentle, the sensitivity of the optical system 100 is reduced, and meanwhile, the chromatic aberration of the optical system 100 is also beneficial to be eliminated. The second lens element L2 and the third lens element L3 each have refractive power. The fourth lens element L4 with positive refractive power is beneficial to correcting the incident angle of the light beam expanded by the second lens element L2 and the third lens element L3. The fourth lens element L4 has a convex object-side surface S7 at a paraxial region 110 and a concave image-side surface S8 at the paraxial region 110. The fifth lens element L5 with negative refractive power has a convex object-side surface S9 at the paraxial region 110 and a concave image-side surface S10 at the paraxial region 110, thereby being beneficial to correcting off-axis aberrations and on-axis aberrations and improving the imaging quality of the optical system 100. With the above-described refractive power and surface-type characteristics, the optical system 100 can be designed to be compact and has high imaging quality.

In addition, in some embodiments, the optical system 100 is provided with a stop STO, which may be disposed on the object side of the first lens L1. In some embodiments, the optical system 100 further includes a filter L6 disposed on the image side of the fifth lens L5. The optical filter L6 may be an infrared band-pass filter, and the optical filter L6 is used for transmitting light in an infrared band and blocking light in other bands, so that the optical system 100 can be applied to the TOF detection field. Specifically, in some embodiments, the filter L6 is capable of transmitting light having wavelengths between 930nm and 950 nm. Of course, the filter L6 can also transmit infrared light with wavelengths in other ranges according to different requirements of application environments. Further, the optical system 100 further includes an image plane S13 located at the image side of the fifth lens L5, where the image plane S13 is an imaging plane of the optical system 100, and the incident light can be imaged on the image plane S13 after being adjusted by the first lens L1, the second lens L2, the third lens L3, the fourth lens L4 and the fifth lens L5.

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

In some embodiments, the materials of the lenses in the optical system 100 may be glass or plastic. The plastic lens can reduce the weight of the optical system 100 and the production cost, and the small size of the optical system 100 is matched to realize the light and thin design of the optical system 100. The lens made of glass material provides the optical system 100 with excellent optical performance and high temperature resistance. It should be noted that the materials of the lenses in the optical system 100 may be any combination of glass and plastic, and are not necessarily all glass or all plastic.

It should 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, where the two or more lenses can form a cemented lens, a surface of the cemented lens closest to the object side may be referred to as an object side surface S1, and a surface closest to the image side may be referred to as an image side surface S2. Alternatively, the first lens L1 does not have a cemented lens, but the distance between the lenses is relatively constant, and 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, the third lens L3, the fourth lens L4, or the fifth lens L5 in some embodiments may be greater than or equal to two, and any adjacent lenses may form a cemented lens therebetween, or may be a non-cemented lens.

Further, in some embodiments, the optical system 100 satisfies the conditional expression: HFOV/FNO of 25 deg.ltoreq.HFOV/FNO of 33 deg.ltoreq.33 deg; where HFOV is one half of the maximum field angle of the optical system 100 and FNO is the f-number of the optical system 100. Specifically, the HFOV/FNO may be: 27.301, 27.638, 28.021, 28.555, 29.314, 29.847, 30.367, 30.449, 31.002 or 31.250, in deg. When the above conditional expression is satisfied, the half field angle and the f-number of the optical system 100 can be reasonably configured, so that the optical system 100 can have both the large field angle and the large aperture characteristic, and can satisfy the requirement of large-scale shooting and the requirement of large light flux of the TOF lens. Exceeding the upper limit of the above conditional expression, the angle of view and aperture of the optical system 100 are too large, which is disadvantageous for light control and thus for improvement of imaging quality. Below the lower limit of the above conditional expression, the angle of view and aperture of the optical system 100 are too small, which results in a reduction in the visible range, difficulty in meeting the requirement for large-scale photographing, and a dark angle phenomenon due to insufficient light flux.

In some embodiments, the optical system 100 satisfies the conditional expression: f/EPD is not less than 1.1 and not more than 1.4; where f is the effective focal length of the optical system 100 and EPD is the entrance pupil diameter of the optical system 100. Specifically, the f/EPD may be: 1.20, 1.22, 1.23, 1.25, 1.28, 1.29, 1.30, 1.31, 1.32, or 1.33. The optical system 100 can have a large aperture characteristic by meeting the above conditional expression, which is beneficial to the optical system 100 to obtain enough light entering quantity, avoids dark angles around an imaging surface, and is beneficial to improving the shooting effect of the optical system 100 in a weak light environment; in addition, the increase of the aperture is also beneficial to shrinking the size of Ai Liban, so that the optical system 100 has a higher resolution limit, and the optical system 100 can meet the design requirement of high pixels by matching with the reasonable matching of the refractive powers of the lenses in the optical system 100.

In some embodiments, the optical system 100 satisfies the conditional expression: SD11/ImgH is more than or equal to 0.4 and less than or equal to 0.6; SD11 is half of the maximum effective aperture of the object side surface S1 of the first lens element L1, and ImgH is half of the image height corresponding to the maximum field angle of the optical system 100. Specifically, SD11/ImgH may be: 0.448, 0.452, 0.457, 0.461, 0.475, 0.493, 0.502, 0.511, 0.532, or 0.544. When the above conditional expression is satisfied, the ratio of the maximum effective half-caliber of the object side surface S1 of the first lens L1 to the half-image height of the optical system 100 can be reasonably configured, which is favorable for reducing the step difference between the lenses in the optical system 100, thereby being favorable for smooth transition of the whole optical system 100, and in addition, is favorable for improving the light flux of the optical system 100, thereby improving the relative illumination of imaging. Exceeding the upper limit of the above conditional expression, the maximum effective aperture of the object side surface S1 of the first lens element L1 is too large, which makes it difficult to control the incident light, and requires a longer structure to achieve smooth transition of the light, thereby being unfavorable for the miniaturized design of the optical system 100. Below the lower limit of the above conditional expression, the maximum effective aperture of the object side surface S1 of the first lens element L1 is too small, resulting in a decrease in light flux, so that the relative illuminance is difficult to reach the design value, and thus it is difficult to satisfy the requirement of the TOF lens for high imaging quality.

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, and the maximum field angle of the optical system can be understood as the maximum field angle of the optical system 100 in the diagonal direction, and ImgH can be understood as half the length of the effective pixel area on the imaging plane of the optical system 100 in the diagonal direction.

In some embodiments, the optical system 100 satisfies the conditional expression: TTL/ImgH is less than or equal to 1.6 and less than or equal to 1.9; wherein TTL is a distance between the object side surface of the first lens element and the imaging surface of the optical system on the optical axis, and ImgH is half of an image height corresponding to a maximum field angle of the optical system. Specifically, TTL/ImgH may be: 1.650, 1.667, 1.693, 1.705, 1.738, 1.766, 1.798, 1.824, 1.833, or 1.848. When the above conditional expression is satisfied, the ratio of the total optical length to the half image height of the optical system 100 can be reasonably configured, which is favorable for shortening the total length of the optical system 100, so that the optical system 100 can realize a miniaturized design. Exceeding the upper limit of the above conditional expression, the total length of the optical system 100 is excessively large, which is disadvantageous in the miniaturization design of the optical system 100. Below the lower limit of the above condition, the total length of the optical system 100 is too short, which causes the surface shape of each lens to be too curved, and high-order aberration is easy to generate, so that the sensitivity between each lens is increased, which is not beneficial to reaching the design specification of the product and improving the imaging performance.

In some embodiments, the optical system 100 satisfies the conditional expression: 2 is less than or equal to |f2/f1 is less than or equal to 17; wherein f2 is the effective focal length of the second lens L2, and f1 is the effective focal length of the first lens L1. Specifically, |f2/f1| may be: 2.349, 2.687, 2.993, 3.552, 4.025, 4.347, 4.637, 6.368, 10.251, or 16.812. When the above conditional expression is satisfied, the ratio of the effective focal lengths of the first lens element L1 and the second lens element L2 can be reasonably configured, so that the refractive power of the second lens element L2 is not too close to that of the first lens element L1, which is favorable for smooth transition of the light rays converged by the first lens element L1 to each lens element in the image space via the second lens element L2, and is also favorable for chromatic aberration on each lens element balance axis in the image space of the second lens element L2 and correction of off-axis coma. Exceeding the upper limit of the above conditional expression, the refractive power of the second lens element L2 is too small, which increases the burden of controlling light by each lens element on the image side, and thus causes excessive bending of the surface shape of each lens element on the object side, which is disadvantageous for improving the imaging quality of the optical system 100. Below the lower limit of the above condition, the refractive powers of the second lens element L2 and the first lens element L1 are too close, resulting in too close light, and the light is not reasonably expanded, which also increases the burden of adjusting the light by each lens element in the image space, thereby being unfavorable for improving the imaging quality.

In some embodiments, the optical system 100 satisfies the conditional expression: BF/TTL is more than or equal to 0.1 and less than or equal to 0.2; herein, BF is the shortest distance between the image side surface S10 of the fifth lens element L5 and the imaging surface of the optical system 100 in the direction of the optical axis 110, and TTL is the distance between the object side surface S1 of the first lens element L1 and the imaging surface of the optical system 100 in the direction of the optical axis 110. Specifically, BF/TTL may be: 0.137, 0.141, 0.148, 0.152, 0.154, 0.158, 0.162, 0.164, 0.169, or 0.176. When the above conditional expression is satisfied, the rear Jiao Zhanbi of the optical system 100 can be reasonably configured, so that the total length of the optical system 100 is shortened to realize a miniaturized design, and meanwhile, the incident angle of the chief ray from the outermost view field to the imaging surface is reasonably controlled, and the relative illuminance reduction caused by the overlarge incident angle of the chief ray from the outermost view field is avoided, thereby being beneficial to improving the imaging quality of the optical system 100.

In some embodiments, the optical system 100 satisfies the conditional expression: SAG42/SAG51 is more than 0 and less than or equal to 3.4; wherein SAG42 is the sagittal height of the image side surface S8 of the fourth lens element L4 at the maximum effective aperture, and SAG51 is the sagittal height of the object side surface S9 of the fifth lens element L5 at the maximum effective aperture. Specifically, SAG42/SAG51 may be: 0.066, 0.154, 0.663, 1.251, 1.751, 2.354, 2.631, 2.894, 3.001, or 3.375. When the above conditional expression is satisfied, the ratio of the image side S8 sagittal height of the fourth lens element L4 to the object side S9 sagittal height of the fifth lens element L5 can be reasonably configured, so that the shapes of the image side S8 of the fourth lens element L4 and the object side S9 of the fifth lens element L5 are matched, which is beneficial to reducing the incident angle of the light beam between the fourth lens element L4 and the fifth lens element L5 on the lens surface, and further beneficial to inhibiting the generation of off-axis chromatic aberration, and meanwhile beneficial to improving the luminous flux of the optical system 100.

In some embodiments, the optical system 100 satisfies the conditional expression: sigma CT/Sigma AT is more than or equal to 1.3 and less than or equal to 2.6; wherein Σct is the sum of thicknesses of the first lens element L1, the second lens element L2, the third lens element L3, the fourth lens element L4 and the fifth lens element L5 on the optical axis 110, and Σat is the sum of air spaces between two adjacent lens elements of the first lens element L1, the second lens element L2, the third lens element L3, the fourth lens element L4 and the fifth lens element L5 on the optical axis. Specifically, Σct/Σat may be: 1.327, 1.551, 1.674, 1.733, 1.829, 1.936, 2.015, 2.238, 2.471, or 2.511. When the above conditional expression is satisfied, the center thickness of each lens in the optical system 100 and the distance between each adjacent lens can be reasonably configured, which is favorable for making the distribution of each lens more uniform, thereby being favorable for smooth transition of light in the optical system 100, further being favorable for eliminating higher-order aberration and improving the imaging quality of the optical system 100.

In some embodiments, the optical system 100 satisfies the conditional expression: f1/f34 is more than or equal to 0.8 and less than or equal to 1.2; wherein f1 is an effective focal length of the first lens L1, and f34 is a combined focal length of the third lens L3 and the fourth lens L4. Specifically, f1/f34 may be: 0.862, 0.887, 0.904, 0.925, 0.938, 0.952, 0.987, 1.022, 1.067, or 1.197. When the above conditional expression is satisfied, the ratio of the effective focal length of the first lens element L1 to the combined focal length of the third lens element L3 and the fourth lens element L4 can be reasonably configured, so that the refractive power of the first lens element L1 is close to the combined refractive power of the third lens element L3 and the fourth lens element L4, and a similar symmetrical structure is formed between the first lens element L1 and the combination of the third lens element L3 and the fourth lens element L4, which is beneficial to correcting the aberration of the optical system 100 and improving the imaging quality of the optical system 100.

The reference wavelengths for the above effective focal length and combined focal length values are 940nm.

From the above description of the embodiments, more particular embodiments and figures are set forth below in detail.

First embodiment

Referring to fig. 1 and 2, fig. 1 is a schematic structural diagram of an optical system 100 in a first embodiment, wherein the optical system 100 includes, in order from an object side to an image side, a stop STO, a first lens element L1 with positive refractive power, a second lens element L2 with positive refractive power, a third lens element L3 with negative refractive power, a fourth lens element L4 with positive refractive power, and a fifth lens element L5 with negative refractive power. Fig. 2 is a graph showing, in order from left to right, the longitudinal spherical aberration, astigmatism and distortion of the optical system 100 according to the first embodiment, the reference wavelength being 940nm, and the other embodiments being identical.

The object side surface S1 of the first lens element L1 is convex at the paraxial region 110 and convex at the peripheral region;

the image-side surface S2 of the first lens element L1 is concave at a paraxial region 110 and convex at a peripheral region;

the object side surface S3 of the second lens element L2 is convex at a paraxial region 110 and concave at a peripheral region;

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

the object side surface S5 of the third lens element L3 is concave at the paraxial region 110 and concave at the peripheral region;

The image-side surface S6 of the third lens element L3 is convex at the paraxial region 110 and convex at the peripheral region;

the fourth lens element L4 has a convex object-side surface S7 at a paraxial region 110 and a concave object-side surface at a peripheral region;

the fourth lens element L4 has a concave image-side surface S8 at a paraxial region 110 and a convex image-side surface at a peripheral region;

the object side surface S9 of the fifth lens element L5 is convex at the paraxial region 110 and concave at the peripheral region;

the image-side surface S10 of the fifth lens element L5 is concave at the paraxial region 110 and convex at the peripheral region.

The object side surfaces and the image side surfaces of the first lens element L1, the second lens element L2, the third lens element L3, the fourth lens element L4 and the fifth lens element L5 are aspheric.

It should be noted that in the present application, when one surface of the lens is described as being convex at the paraxial region 110 (the central region of the surface), it is understood that the region of the surface of the lens near the optical axis 110 is convex. When describing a surface of a lens as concave at the circumference, it is understood that the surface is concave in the area near the maximum effective radius. For example, when the surface is convex at the paraxial region 110 and also convex at the circumference, the shape of the surface from the center (the intersection of the surface and the optical axis 110) to the edge direction may be purely convex; or first transition from a convex shape in the center to a concave shape and then become convex near the maximum effective radius. The various shape structures (concave-convex relationship) of the surface are not fully revealed here only for the purpose of explaining the relationship at the optical axis 110 with the circumference, but other cases may be deduced from the above examples.

The materials of the first lens L1, the second lens L2, the third lens L3, the fourth lens L4 and the fifth lens L5 are all plastics.

Further, the optical system 100 satisfies the conditional expression: HFOV/fno= 29.851deg; where HFOV is one half of the maximum field angle of the optical system 100 and FNO is the f-number of the optical system 100. When the above conditional expression is satisfied, the half field angle and the f-number of the optical system 100 can be reasonably configured, so that the optical system 100 can have both the large field angle and the large aperture characteristic, and can satisfy the requirement of large-scale shooting and the requirement of large light flux of the TOF lens.

The optical system 100 satisfies the conditional expression: f/epd=1.33; where f is the effective focal length of the optical system 100 and EPD is the entrance pupil diameter of the optical system 100. The optical system 100 can have a large aperture characteristic by meeting the above conditional expression, which is beneficial to the optical system 100 to obtain enough light entering quantity, avoids dark angles around an imaging surface, and is beneficial to improving the shooting effect of the optical system 100 in a weak light environment; in addition, the increase of the aperture is also beneficial to shrinking the size of Ai Liban, so that the optical system 100 has a higher resolution limit, and the optical system 100 can meet the design requirement of high pixels by matching with the reasonable matching of the refractive powers of the lenses in the optical system 100.

The optical system 100 satisfies the conditional expression: SD 11/imgh=0.448; SD11 is half of the maximum effective aperture of the object side surface S1 of the first lens element L1, and ImgH is half of the image height corresponding to the maximum field angle of the optical system 100. When the above conditional expression is satisfied, the ratio of the maximum effective half-caliber of the object side surface S1 of the first lens L1 to the half-image height of the optical system 100 can be reasonably configured, which is favorable for reducing the step difference between the lenses in the optical system 100, thereby being favorable for smooth transition of the whole optical system 100, and in addition, is favorable for improving the light flux of the optical system 100, thereby improving the relative illumination of imaging.

The optical system 100 satisfies the conditional expression: TTL/imgh=1.700; wherein TTL is a distance between the object side surface of the first lens element and the imaging surface of the optical system on the optical axis, and ImgH is half of an image height corresponding to a maximum field angle of the optical system. When the above conditional expression is satisfied, the ratio of the total optical length to the half image height of the optical system 100 can be reasonably configured, which is favorable for shortening the total length of the optical system 100, so that the optical system 100 can realize a miniaturized design.

The optical system 100 satisfies the conditional expression: |f2/f1|= 6.802; wherein f2 is the effective focal length of the second lens L2, and f1 is the effective focal length of the first lens L1. When the above conditional expression is satisfied, the ratio of the effective focal lengths of the first lens element L1 and the second lens element L2 can be reasonably configured, so that the refractive power of the second lens element L2 is not too close to that of the first lens element L1, which is favorable for smooth transition of the light rays converged by the first lens element L1 to each lens element in the image space via the second lens element L2, and is also favorable for chromatic aberration on each lens element balance axis in the image space of the second lens element L2 and correction of off-axis coma.

The optical system 100 satisfies the conditional expression: BF/ttl=0.176; herein, BF is the shortest distance between the image side surface S10 of the fifth lens element L5 and the imaging surface of the optical system 100 in the direction of the optical axis 110, and TTL is the distance between the object side surface S1 of the first lens element L1 and the imaging surface of the optical system 100 in the direction of the optical axis 110. When the above conditional expression is satisfied, the rear Jiao Zhanbi of the optical system 100 can be reasonably configured, so that the total length of the optical system 100 is shortened to realize a miniaturized design, and meanwhile, the incident angle of the chief ray from the outermost view field to the imaging surface is reasonably controlled, and the relative illuminance reduction caused by the overlarge incident angle of the chief ray from the outermost view field is avoided, thereby being beneficial to improving the imaging quality of the optical system 100.

The optical system 100 satisfies the conditional expression: SAG 42/sag51=1.060; wherein SAG42 is the sagittal height of the image side surface S8 of the fourth lens element L4 at the maximum effective aperture, and SAG51 is the sagittal height of the object side surface S9 of the fifth lens element L5 at the maximum effective aperture. When the above conditional expression is satisfied, the ratio of the image side S8 sagittal height of the fourth lens element L4 to the object side S9 sagittal height of the fifth lens element L5 can be reasonably configured, so that the shapes of the image side S8 of the fourth lens element L4 and the object side S9 of the fifth lens element L5 are matched, which is beneficial to reducing the incident angle of the light beam between the fourth lens element L4 and the fifth lens element L5 on the lens surface, and further beneficial to inhibiting the generation of off-axis chromatic aberration, and meanwhile beneficial to improving the luminous flux of the optical system 100.

The optical system 100 satisfies the conditional expression: Σct/Σat= 2.511; wherein Σct is the sum of thicknesses of the first lens element L1, the second lens element L2, the third lens element L3, the fourth lens element L4 and the fifth lens element L5 on the optical axis 110, and Σat is the sum of air spaces between two adjacent lens elements of the first lens element L1, the second lens element L2, the third lens element L3, the fourth lens element L4 and the fifth lens element L5 on the optical axis. When the above conditional expression is satisfied, the center thickness of each lens in the optical system 100 and the distance between each adjacent lens can be reasonably configured, which is favorable for making the distribution of each lens more uniform, thereby being favorable for smooth transition of light in the optical system 100, further being favorable for eliminating higher-order aberration and improving the imaging quality of the optical system 100.

The optical system 100 satisfies the conditional expression: f1/f34=0.906; wherein f1 is an effective focal length of the first lens L1, and f34 is a combined focal length of the third lens L3 and the fourth lens L4. When the above conditional expression is satisfied, the ratio of the effective focal length of the first lens element L1 to the combined focal length of the third lens element L3 and the fourth lens element L4 can be reasonably configured, so that the refractive power of the first lens element L1 is close to the combined refractive power of the third lens element L3 and the fourth lens element L4, and a similar symmetrical structure is formed between the first lens element L1 and the combination of the third lens element L3 and the fourth lens element L4, which is beneficial to correcting the aberration of the optical system 100 and improving the imaging quality of the optical system 100.

In addition, various parameters of the optical system 100 are given in table 1. The image plane S13 in table 1 can be understood as the imaging plane of the optical system 100. The elements from the object plane (not shown) to the image plane S13 are arranged in the order of the elements from top to bottom in table 1. The radius Y in table 1 is the radius of curvature of the object or image side of the corresponding surface number at the optical axis 110. The surface numbers S1 and S2 are the object side surface S1 and the image side surface S2 of the first lens element L1, respectively, i.e., the surface with the smaller surface number is the object side surface and the surface with the larger surface number is the image side surface in the same lens element. The first value in the "thickness" parameter row of the first lens element L1 is the thickness of the lens element on the optical axis 110, and the second value is the distance from the image side surface of the lens element to the rear surface of the image side direction on the optical axis 110.

Note that in this embodiment and the following embodiments, the optical system 100 may not be provided with the optical filter L6, but the distance from the image side surface S10 to the image surface S13 of the fifth lens L5 remains unchanged.

In the first embodiment, the effective focal length f=2.33 mm, the optical total length ttl=3.33 mm, the maximum field angle fov=75 deg, and the f-number fno=1.33 of the optical system 100. The optical system 100 has excellent imaging quality, can be designed to be compact, and has a large aperture characteristic.

The reference wavelength of the focal length of each lens is 940nm, and the reference wavelength of the refractive index and Abbe number of each lens is 587.56nm, and other embodiments are the same.

TABLE 1

Further, the aspherical coefficients of the image side or object side of each lens of the optical system 100 are given in table 2. Wherein the plane numbers S1-S10 represent the image side surfaces or the object side surfaces S1-S10, respectively. And K-a20 from top to bottom respectively represent types of aspherical coefficients, where K represents a conic coefficient, A4 represents four times an aspherical coefficient, A6 represents six times an aspherical coefficient, A8 represents eight times an aspherical coefficient, and so on. In addition, the aspherical coefficient formula is as follows:

where Z is the distance from the corresponding point on the aspheric surface to the plane tangential 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 vertex, K is the conic coefficient, ai is the coefficient corresponding to the i-th higher term in the aspheric surface formula.

TABLE 2

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In addition, fig. 2 includes a longitudinal spherical aberration plot (Longitudinal Spherical Aberration) of the optical system 100, the longitudinal spherical aberration plot representing the focus deviation of light rays of different wavelengths after passing through the lens, wherein the ordinate represents the normalized pupil coordinates (Normalized Pupil Coordinator) from the pupil center to the pupil edge, and the abscissa represents the focus deviation, i.e., the distance (in mm) from the imaging plane to the intersection of the light rays with the optical axis 110. As can be seen from the longitudinal spherical aberration chart, the degree of focus deviation of the light rays of each wavelength in the first embodiment tends to be uniform, and the diffuse spots or the halos in the imaging picture are effectively suppressed. Fig. 2 also includes an astigmatic curve diagram (ASTIGMATIC FIELD CURVES) of the optical system 100, wherein the abscissa represents the focus offset, the ordinate represents the image height in mm, and the S-curve in the astigmatic curve represents the sagittal field curve at 940nm and the T-curve represents the meridional field curve at 940 nm. As can be seen from the figure, the field curvature of the optical system 100 is small, the field curvature and astigmatism of each field of view are well corrected, and the center and the edge of the field of view have clear imaging. Fig. 2 also includes a DISTORTION graph (DISTORTION) of the optical system 100, where the DISTORTION graph represents DISTORTION magnitude values for different field angles, and where the abscissa represents DISTORTION value in% and the ordinate represents image height in mm. As can be seen from the figure, 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 an optical system 100 in a second embodiment, wherein the optical system 100 includes, in order from an object side to an image side, a stop STO, a first lens element L1 with positive refractive power, a second lens element L2 with positive refractive power, a third lens element L3 with negative refractive power, a fourth lens element L4 with positive refractive power, and a fifth lens element L5 with negative refractive power. Fig. 4 is a graph showing longitudinal spherical aberration, astigmatism and distortion of the optical system 100 in the second embodiment in order from left to right.

the image-side surface S2 of the first lens element L1 is concave at the paraxial region 110 and concave at the peripheral region;

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

TABLE 3 Table 3

Further, the aspheric coefficients of the image side or the object side of each lens of the optical system 100 are given in table 4, and the definition of each parameter can be obtained from the first embodiment, which is not described herein.

TABLE 4 Table 4

From the above provided parameter information, the following data can be deduced:

HFOV/FNO(deg)	28.195	BF/TTL	0.162
				f/EPD	1.33	SAG42/SAG51	0.066
SD11/ImgH	0.491	∑CT/∑AT	1.647
				TTL/ImgH	1.848	f1/f34	0.966
\|f2/f1\|	4.819

in addition, as can be seen from the aberration diagram in fig. 4, the longitudinal spherical aberration, astigmatism and distortion of the optical system 100 are all 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 an optical system 100 in a third embodiment, wherein the optical system 100 includes, in order from an object side to an image side, a stop STO, a first lens element L1 with positive refractive power, a second lens element L2 with positive refractive power, a third lens element L3 with negative refractive power, a fourth lens element L4 with positive refractive power, and a fifth lens element L5 with negative refractive power. Fig. 6 is a graph showing longitudinal spherical aberration, astigmatism and distortion of the optical system 100 in the third embodiment in order from left to right.

the object side surface S5 of the third lens element L3 is convex at a paraxial region 110 and concave at a peripheral region;

the image-side surface S6 of the third lens element L3 is concave at a paraxial region 110 and convex at a peripheral region;

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

TABLE 5

Further, the aspheric coefficients of the image side or the object side of each lens of the optical system 100 are given in table 6, and the definition of each parameter can be obtained from the first embodiment, which is not described herein.

TABLE 6

And, according to the above-provided parameter information, the following data can be deduced:

HFOV/FNO(deg)	27.301	BF/TTL	0.164
				f/EPD	1.32	SAG42/SAG51	1.192
SD11/ImgH	0.500	∑CT/∑AT	1.385
				TTL/ImgH	1.650	f1/f34	0.929
\|f2/f1\|	2.349

in addition, as is clear from the aberration diagram in fig. 6, the longitudinal spherical aberration, astigmatism and distortion of the optical system 100 are all 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 an optical system 100 in a fourth embodiment, wherein the optical system 100 includes, in order from an object side to an image side, a stop STO, a first lens element L1 with positive refractive power, a second lens element L2 with positive refractive power, a third lens element L3 with negative refractive power, a fourth lens element L4 with positive refractive power, and a fifth lens element L5 with negative refractive power. Fig. 8 is a graph showing longitudinal spherical aberration, astigmatism and distortion of the optical system 100 in the fourth embodiment in order from left to right.

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

TABLE 7

Further, the aspheric coefficients of the image side or the object side of each lens in the optical system 100 are given in table 8, and the definition of each parameter can be obtained from the first embodiment, which is not described herein.

TABLE 8

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HFOV/FNO(deg)	28.682	BF/TTL	0.145
				f/EPD	1.28	SAG42/SAG51	3.375
SD11/ImgH	0.514	∑CT/∑AT	1.619
				TTL/ImgH	1.798	f1/f34	0.862
\|f2/f1\|	4.190

in addition, as is clear from the aberration diagram in fig. 8, the longitudinal spherical aberration, astigmatism and distortion of the optical system 100 are all 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 an optical system 100 in a fifth embodiment, wherein the optical system 100 includes, in order from an object side to an image side, a stop STO, a first lens element L1 with positive refractive power, a second lens element L2 with negative refractive power, a third lens element L3 with positive refractive power, a fourth lens element L4 with positive refractive power, and a fifth lens element L5 with negative refractive power. Fig. 10 is a graph showing longitudinal spherical aberration, astigmatism and distortion of the optical system 100 in the fifth embodiment in order from left to right.

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

TABLE 9

Further, the aspheric coefficients of the image side or the object side of each lens of the optical system 100 are given in table 10, and the definition of each parameter can be obtained from the first embodiment, which is not described herein.

Table 10

HFOV/FNO(deg)	31.250	BF/TTL	0.137
				f/EPD	1.19	SAG42/SAG51	0.799
SD11/ImgH	0.544	∑CT/∑AT	1.327
				TTL/ImgH	1.824	f1/f34	1.197
\|f2/f1\|	16.812

in addition, as is clear from the aberration diagram in fig. 10, the longitudinal spherical aberration, astigmatism and distortion of the optical system 100 are all 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 photosensitive surface of the photosensitive element 210 can be regarded as the image surface S13 of the optical system 100. The image capturing module 200 may further be provided with an optical filter L6, where the optical filter L6 is disposed between the image side surface S10 and the image plane S13 of the fifth lens element L5. In some embodiments, filter L6 is transmissive to infrared light at wavelengths of 930nm-950 nm. Specifically, the photosensitive element 210 may be a charge coupled element (Charge Coupled Device, CCD) or a complementary metal oxide semiconductor device (Complementary Metal-Oxide Semiconductor Sensor, CMOS Sensor). The optical system 100 is adopted in the image capturing module 200, and the optical system has good imaging quality and large aperture characteristic, so that the requirement of large light flux of the TOF lens can be met.

Referring to fig. 11 and 12, in some embodiments, the image capturing module 200 can be applied to an electronic device 300, which includes a housing 310, and the image capturing module 200 is disposed on the housing 310. Specifically, the electronic device 300 may be, but is not limited to, a portable telephone, a video phone, a smart phone, an electronic book reader, a vehicle-mounted image pickup device such as a car recorder, or a wearable device such as a smart watch. When the electronic device 300 is a smart phone, the housing 310 may be a middle frame of the electronic device 300. The image capturing module 200 is adopted in the electronic device 300, and has good imaging quality and large aperture characteristic, so that the application of the electronic device in the TOF detection field is facilitated.

Further, in some embodiments, the electronic device 300 is applied in the field of TOF detection, and then the electronic device 300 may be an infrared detection device based on time of flight (TOF) or an apparatus configured with an infrared detection function. The electronic device 300 further includes a projection module 320, where the projection module 320 is configured to emit infrared light to the object to be detected, and the infrared light emitted by the projection module 320 is received by the image capturing module 200 after being reflected by the object to be detected, thereby obtaining three-dimensional depth information of the object to be detected, and realizing a three-dimensional detection function.

The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The above examples illustrate only a few embodiments of the invention, which are described in detail and are not to be construed as limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. Accordingly, the scope of protection of the present invention is to be determined by the appended claims.

Claims

1. An optical system, characterized in that the number of lenses with refractive power in the optical system is five, and the optical system sequentially comprises, from an object side to an image side along an optical axis:

a third lens element with refractive power;

and the optical system satisfies the following conditional expression:

25deg≤HFOV/FNO≤33deg；

0.4≤SD11/ImgH≤0.6；

0.1≤BF/TTL≤0.2；

the HFOV is half of the maximum field angle of the optical system, the FNO is half of the f-number of the optical system, the SD11 is half of the maximum effective aperture of the object side surface of the first lens, the ImgH is half of the image height corresponding to the maximum field angle of the optical system, the BF is the shortest distance between the image side surface of the fifth lens and the imaging surface of the optical system in the optical axis direction, and the TTL is the distance between the object side surface of the first lens and the imaging surface of the optical system in the optical axis direction.

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

1.1≤f/EPD≤1.4；

where f is the effective focal length of the optical system and EPD is the entrance pupil diameter of the optical system.

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

1.6≤TTL/ImgH≤1.9。

4. the optical system of claim 1, wherein the optical system satisfies the following conditional expression:

0.8≤f1/f34≤1.2；

wherein f1 is an effective focal length of the first lens, and f34 is a combined focal length of the third lens and the fourth lens.

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

2≤|f2/f1|≤17；

wherein f2 is the effective focal length of the second lens, and f1 is the effective focal length of the first lens.

6. The optical system of claim 1, further comprising a stop disposed on an object side of the first lens.

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

0＜SAG42/SAG51≤3.4；

wherein SAG42 is the sagittal height of the image side surface of the fourth lens element at the maximum effective aperture, and SAG51 is the sagittal height of the object side surface of the fifth lens element at the maximum effective aperture.

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

1.3≤∑CT/∑AT≤2.6；

and Σct is the sum of thicknesses of the first lens, the second lens, the third lens, the fourth lens and the fifth lens on the optical axis, and Σat is the sum of air intervals of two adjacent lenses of the first lens, the second lens, the third lens, the fourth lens and the fifth lens on the optical axis.

9. An image capturing module comprising a photosensitive element and the optical system of any one of claims 1-8, wherein the photosensitive element is disposed on an image side of the optical system.

10. An electronic device, comprising a housing and the image capturing module of claim 9, wherein the image capturing module is disposed on the housing.