CN112904528A

CN112904528A - Optical imaging system, image capturing module and electronic equipment

Info

Publication number: CN112904528A
Application number: CN201911217827.7A
Authority: CN
Inventors: 谢晗; 邹金华; 李明
Original assignee: Jiangxi Jingchao Optical Co Ltd
Current assignee: Jiangxi Jingchao Optical Co Ltd
Priority date: 2019-12-03
Filing date: 2019-12-03
Publication date: 2021-06-04

Abstract

The application relates to an optical imaging system, an image capturing module and an electronic device. The optical imaging system sequentially comprises a first lens with positive refractive power from an object side to an image side, and the object side surface of the first lens is a convex surface; a second lens element with refractive power having a concave image-side surface; a third lens element with refractive power; a fourth lens element with refractive power; the image side surface of the fifth lens element is concave at the optical axis, and at least one inflection point exists on the object side surface and the image side surface of the fifth lens element; and the optical imaging system satisfies the conditional expression: CT1/TTL is more than or equal to 0.19; the CT1 is the center thickness of the first lens element, and the TTL is the distance on the optical axis from the object-side surface of the first lens element to the image plane of the optical imaging system. When the condition is met, the optical imaging system is provided with the thicker first lens, the depth of the optical imaging system is deepened, the shape of the ultra-small head with the small outer diameter is manufactured, and the total length of the optical imaging system cannot be excessively increased.

Description

Optical imaging system, image capturing module and electronic equipment

Technical Field

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

Background

In recent years, portable electronic devices such as smart phones having a camera function have been rapidly updated, and particularly full-screen mobile phones have made higher demands on a camera lens to be used therewith, and an optical imaging system needs to be small enough in size. With the development of the CMOS chip technology, the pixel size of the chip is smaller and smaller, the imaging quality requirement for the matched optical imaging system is higher and higher, and the size of the common high-pixel camera lens is larger, which is difficult to match with electronic devices such as a full-screen mobile phone.

Disclosure of Invention

Therefore, it is necessary to provide an optical imaging system, an image capturing module and an electronic device for solving the problem that the optical imaging system has a large size and is difficult to match with electronic devices such as a full-screen mobile phone.

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

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

the second lens element with refractive power has a concave image-side surface;

a third lens element with refractive power;

a fourth lens element with refractive power;

the optical axis of the fifth lens element is concave, and at least one inflection point exists on the object-side surface and the image-side surface of the fifth lens element;

and the optical imaging system satisfies the following conditional expression:

CT1/TTL≥0.19；

wherein, CT1 is the center thickness of the first lens element, and TTL is the distance on the optical axis from the object-side surface of the first lens element to the image plane of the optical imaging system.

When the condition is met, the optical imaging system is provided with the thicker first lens, and when the lens is arranged in the shape, the depth of the optical imaging system is deepened, the ultra-small head shape with a small outer diameter is manufactured, and the optical imaging system can be matched with electronic equipment such as a full-screen mobile phone easily. The first lens element with positive refractive power helps to shorten the total length of the optical imaging system, and the object-side surface of the first lens element is convex, so that the positive refractive power of the first lens element can be further enhanced, and the size of the optical imaging system in the optical axis direction can be shortened. With such an arrangement, even if the first lens is thick, the total length of the optical imaging system is not excessively increased, which is advantageous for the compact design of the optical imaging system. In addition, at least one inflection point exists in the object side surface and the image side surface of the fifth lens, so that the aberration of an off-axis field can be corrected, and the imaging quality is improved.

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

ET1≥0.555；

wherein ET1 is the edge thickness of the first lens, ET1 is in mm, i.e. the thickness of the first lens at the maximum effective clear aperture, and ET1 is in mm. When the condition is met, the optical imaging system can be guaranteed to have larger depth, the thicker the first lens is, the deeper the depth of the optical imaging system is, and the front end of the lens can be better matched with electronic equipment such as a full-face screen mobile phone.

CT1/ImgH≥0.25；

wherein ImgH is half of the diagonal length of the effective pixel area of the optical imaging system. When the condition formula is met, under the condition that the chips with the same size are matched, the larger the thickness of the first lens is, the closer the object side surface of the first lens is to the image surface of the optical imaging system, and when the requirement of the depth of the optical imaging system is met, the first lens can be guaranteed to have enough edge thickness to bear against the lens barrel, so that the optical imaging system is high in assembly stability and good in processing manufacturability.

0.2＜R10/f＜0.7；

wherein R10 is the radius of curvature of the image-side surface of the fifth lens element at paraxial region, and f is the total effective focal length of the optical imaging system. When the conditional expressions are satisfied, the image side surface of the fifth lens element is concave at the paraxial region, so that negative refractive power is provided, the back focal length can be adjusted, the field curvature can be effectively corrected, and the imaging quality can be improved.

2.2≤FNO≤3.0；

wherein FNO is an f-number of the optical imaging system. When the condition formula is met, the optical imaging system has a proper light passing aperture, the light passing amount requirement of the optical imaging system is met, the diameter of the entrance pupil can not be too large, the lens head can be ensured to have a smaller outer diameter, the appearance requirement of a super-small head is met, and the optical imaging system can be matched with electronic equipment such as a full-screen mobile phone more easily.

SD1/ImgH＜0.26；

wherein SD1 is the maximum effective radius of the object side surface of the first lens, and ImgH is half of the diagonal length of the optical imaging system in the effective pixel area. The smaller the optical effective radius of the object-side surface of the first lens is, the more advantageous the reduction of the outer diameter of the lens head is. When the conditional expression is met, the ratio of SD1/ImgH is reasonably configured, so that the design of a small outer diameter of the lens head can be considered when a high-pixel large-size chip is matched.

CT1/OAL＞0.22；

and the OAL is the distance from the object side surface of the first lens to the image side surface of the fifth lens on the optical axis. If CT1/OAL is less than 0.22, the thickness of the first lens is insufficient, which results in insufficient depth of the optical imaging system, insufficient bearing of the first lens on the lens barrel, and poor manufacturability. When the condition is satisfied, the thickness of the first lens is larger, the optical imaging system has deeper depth, and the first lens can fully bear against the lens cone, so that the assembly stability of the optical imaging system is high, and the processing manufacturability is good.

tan(ω/2)＜1.0；

where ω is the maximum field angle of the optical imaging system. When the condition formula is satisfied, the optical imaging system has a sufficiently large field angle, and the photographing experience of the user can be satisfied when the optical imaging system is used for the electronic equipment with the photographing function.

0.3＜f1/f234＜2；

wherein f1 is the effective focal length of the first lens, and f234 is the combined focal length of the second lens, the third lens and the fourth lens. When the conditional expressions are satisfied, the first lens provides larger positive refractive power, and the spherical aberration generated by the first lens can be effectively corrected by reasonably configuring the refractive powers of the second lens, the third lens and the fourth lens, so that the imaging quality is improved.

An image capturing module includes a photosensitive element and the optical imaging system of any of the above embodiments, wherein the photosensitive element is disposed on an image side of the optical imaging system. The optical imaging system is adopted in the image capturing module, the pixel is high, the imaging quality is good, the outer diameter of the head of the lens which is beneficial to being manufactured is small, and the depth of the optical imaging system is deep.

An electronic device comprises a shell and the image capturing module, wherein the image capturing module is arranged on the shell. Above-mentioned electronic equipment, the camera lens head external diameter of getting for instance the module is little, and optical imaging system's degree of depth is dark, matches the installation of casing more easily.

Drawings

FIG. 1 is a schematic view of a first embodiment of an optical imaging system of the present application;

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

FIG. 3 is a schematic view of a second embodiment of an optical imaging system of the present application;

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

FIG. 5 is a schematic view of a third embodiment of an optical imaging system of the present application;

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

FIG. 7 is a schematic view of a fourth embodiment of an optical imaging system of the present application;

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

FIG. 9 is a schematic view of a fifth embodiment of an optical imaging system of the present application;

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

FIG. 11 is a schematic view of a sixth embodiment of an optical imaging system of the present application;

FIG. 12 is a spherical aberration diagram, an astigmatism diagram and a distortion diagram of a sixth embodiment of the optical imaging system of the present application;

FIG. 13 is a schematic view of a seventh embodiment of an optical imaging system of the present application;

FIG. 14 is a spherical aberration diagram, an astigmatism diagram and a distortion diagram of a seventh embodiment of the optical imaging system of the present application;

FIG. 15 is a schematic view of an image capture module according to an embodiment of the present application;

fig. 16 is a schematic diagram of an embodiment of an electronic device of the present application.

Detailed Description

To facilitate an understanding of the invention, the invention will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

It will be understood that when an element is referred to as being "secured to" 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 "inner", "outer", "left", "right" and the like as used herein are for illustrative purposes only and do not represent the only embodiments.

In recent years, portable electronic devices such as smart phones having a camera function have been rapidly updated, and particularly full-screen mobile phones have made higher demands on a camera lens to be used therewith, and an optical imaging system needs to be small enough in size. With the development of the CMOS chip technology, the pixel size of the chip is smaller and smaller, the imaging quality requirement for the matched optical imaging system is higher and higher, and the imaging quality of the common high-pixel camera lens can be ensured by superimposing the number of lenses, but the optical imaging system is large and difficult to match with a full-screen mobile phone.

In order to solve the above problems, embodiments of the present application provide an optical imaging system, an image capturing module and an electronic device.

In one embodiment of the present application, referring to fig. 1, an optical imaging system 100 includes, in order from an object side to an image side, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, and a fifth lens L5. Specifically, the first lens element L1 includes an object-side surface S1 and an image-side surface S2, the second lens element L2 includes an object-side surface S3 and an image-side surface S4, the third lens element L3 includes an object-side surface S5 and an image-side surface S6, the fourth lens element L4 includes an object-side surface S7 and an image-side surface S8, and the fifth lens element L5 includes an object-side surface S9 and an image-side surface S10.

The first lens element L1 with positive refractive power helps to shorten the total length of the optical imaging system 100, and the object-side surface S1 of the first lens element L1 is convex, so that the positive refractive power of the first lens element L1 can be further enhanced, the size of the optical imaging system 100 in the optical axis direction is shortened, and the optical imaging system 100 can be miniaturized. The second lens element L2, the third lens element L3 and the fourth lens element L4 have refractive power, and the image-side surface S4 of the second lens element L2 is concave. The fifth lens element L5 with negative refractive power has a concave image-side surface S10 of the fifth lens element L5 on the optical axis. At least one inflection point exists in the object side surface S9 and the image side surface S10 of the fifth lens L5 to correct the aberration of the off-axis field of view, thereby improving the imaging quality.

In addition, in some embodiments, the optical imaging system 100 is provided with a stop STO, which may be disposed on the object side of the first lens L1 or between the first lens L1 and the second lens L2. In some embodiments, the optical imaging system 100 further includes an infrared filter L6 disposed on the image side of the fifth lens L5, and the infrared filter L6 includes an object-side surface S11 and an image-side surface S12. Note that the infrared filter L6 is an infrared cut filter. As shown in fig. 15, when the optical imaging system 100 is used in the image capturing module 200, the infrared filter L6 is used for filtering the interference light and preventing the interference light from reaching the photosensitive element 210 to affect the normal imaging. Furthermore, the optical imaging system 100 further includes an image plane S13 located on the image side of the fifth lens L5, 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. It is understood that, as shown in fig. 15, when the optical imaging system 100 is used on the image capturing module 200, the image surface S13 may be a photosensitive surface of the photosensitive element 210.

In some embodiments, both the object-side surface and the image-side surface of each lens of the optical imaging system 100 are 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 imaging 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 imaging system 100 may be an aspheric surface or any combination of spherical surfaces.

In some embodiments, each lens in the optical imaging system 100 may be made of glass or plastic. The use of plastic lenses reduces the weight and production cost of the optical imaging system 100, while the use of glass lenses provides the optical imaging system 100 with excellent optical properties and high temperature resistance. It should be noted that the material of each lens in the optical imaging system 100 may also be any combination of glass and plastic, and is not necessarily both glass and plastic.

Further, in some embodiments, the optical imaging system 100 satisfies the conditional expression: CT1/TTL is more than or equal to 0.19; wherein, CT1 is the center thickness of the first lens L1, and TTL is the distance on the optical axis from the object-side surface S1 of the first lens L1 to the image surface S13 of the optical imaging system 100. Specifically, CT1/TTL may be 0.190, 0.195, 0.200, 0.213, 0.220, 0.225, 0.236, 0.242, 0.255, or 0.260. When the above conditional expressions are satisfied, the optical imaging system 100 has the first lens L1 with a relatively thick thickness, and when the lenses are arranged in the shape, the depth of the optical imaging system 100 is increased, and the optical imaging system is manufactured into a super-small head shape with a small outer diameter, and can be better matched with electronic equipment such as a full-screen mobile phone.

In some embodiments, the optical imaging system 100 satisfies the conditional expression: ET1 is more than or equal to 0.555; ET1 is the thickness of the edge of the first lens L1, i.e. the thickness of the first lens L1 at the maximum effective clear aperture, and ET1 is expressed in mm. Specifically, ET1 may be 0.555, 0.566, 0.595, 0.620, 0.682, 0.734, 0.825, 0.876, 0.930, or 1. Satisfying above-mentioned conditional expression, can guaranteeing that optical imaging system 100 has great degree of depth, first lens L1 is thicker, and optical imaging system 100's degree of depth is darker, makes the front end of camera lens can match electronic equipment such as full-face screen cell-phone better.

In some embodiments, the optical imaging system 100 satisfies the conditional expression: CT1/ImgH is more than or equal to 0.25; wherein CT1 is the center thickness of the first lens L1, and ImgH is half of the diagonal length of the effective pixel area of the optical imaging system 100. Specifically, CT1/ImgH may be 0.250, 0.265, 0.273, 0.288, 0.301, 0.316, 0.329, 0.344, 0.350, or 0.365. When the above conditional expressions are satisfied, under the condition of matching chips of the same size, the larger the thickness of the first lens L1 is, the closer the object side surface S1 of the first lens L1 is to the image surface S13 of the optical imaging system 100, and when the depth requirement of the optical imaging system 100 is satisfied, the sufficient edge thickness of the first lens L1 can be ensured to bear against the lens barrel, so that the assembly stability of the optical imaging system 100 is high, and the processing manufacturability is good.

In some embodiments, the optical imaging system 100 satisfies the conditional expression: r10/f is more than 0.2 and less than 0.7; where R10 is the radius of curvature of the image-side surface S10 of the fifth lens element L5 at the paraxial region, and f is the total effective focal length of the optical imaging system 100. Specifically, R10/f may be 0.240, 0.267, 0.292, 0.325, 0.385, 0.472, 0.511, 0.560, 0.615, or 0.628. When the above conditional expressions are satisfied, the image-side surface S10 of the fifth lens element L5 is concave at the paraxial region, so as to provide negative refractive power, adjust the back focal length, effectively correct curvature of field, and improve the imaging quality.

In some embodiments, the optical imaging system 100 satisfies the conditional expression: FNO is more than or equal to 2.2 and less than or equal to 3.0; wherein FNO is the f-number of the optical imaging system 100. Specifically, FNO can be 2.26, 2.31, 2.45, 2.50, 2.67, 2.73, 2.80, 2.86, 2.93, or 3. When the above conditional expressions are satisfied, the optical imaging system 100 has a proper clear aperture, which not only satisfies the requirement of the clear light amount of the optical imaging system 100, but also considers that the diameter of the entrance pupil is not too large, ensures that the lens head has a smaller outer diameter, satisfies the appearance requirement of a super-small head, and is easier to match with electronic devices such as a full-screen mobile phone.

In some embodiments, the optical imaging system 100 satisfies the conditional expression: SD1/ImgH < 0.26; wherein SD1 is the maximum effective radius of the object-side surface S1 of the first lens L1, and ImgH is half the length of the diagonal line of the optical imaging system 100 in the effective pixel area. Specifically, SD1/ImgH may be 0.183, 0.191, 0.198, 0.200, 0.209, 0.215, 0.229, 0.240, 0.249, or 0.255. The smaller the optically effective radius of the object-side surface S1 of the first lens L1, the more advantageous the outer diameter of the lens head is to be reduced. When the conditional expression is met, the ratio of SD1/ImgH is reasonably configured, so that the design of a small outer diameter of the lens head can be considered when a high-pixel large-size chip is matched.

In some embodiments, the optical imaging system 100 satisfies the conditional expression: CT1/OAL > 0.22; here, CT1 is the center thickness of the first lens L1, and OAL is the distance on the optical axis from the object-side surface S1 of the first lens L1 to the image-side surface S1 of the fifth lens L5. Specifically, CT1/OAL may be 0.230, 0.239, 0.245, 0.260, 0.267, 0.271, 0.295, 0.310, 0.325, or 0.336. If the CT1/OAL is less than 0.22, the thickness of the first lens L1 is insufficient, which results in insufficient depth of the optical imaging system 100 and insufficient support of the first lens L1 against the lens barrel, resulting in poor manufacturability. When the above conditional expressions are satisfied, the thickness of the first lens L1 is large, the optical imaging system 100 has a deep depth, and the first lens L1 can fully bear against the lens barrel, so that the assembly stability of the optical imaging system 100 is high, and the processing manufacturability is good.

In some embodiments, the optical imaging system 100 satisfies the conditional expression: tan (omega/2) < 1.0; where ω is the maximum field angle of the optical imaging system 100. Specifically, tan (ω/2) may be 0.803, 0.810, 0.832, 0.845, 0.859, 0.865, 0.880, 0.892, 0.915, or 0.933. When the above conditional expressions are satisfied, the optical imaging system 100 has a sufficiently large angle of view, and can satisfy the user's photographing experience when used in an electronic device having a camera function.

In some embodiments, the optical imaging system 100 satisfies the conditional expression: f1/f234 is more than 0.3 and less than 2; wherein f1 is the effective focal length of the first lens L1, and f234 is the combined focal length of the second lens L2, the third lens L3 and the fourth lens L4. Specifically, f1/f234 may be 0.375, 0.386, 0.557, 0.805, 0.976, 1.225, 1.410, 1.575, 1.681, or 1.776. When the above conditional expressions are satisfied, the first lens element L1 provides a large positive refractive power, and the spherical aberration generated by the first lens element L1 can be effectively corrected by reasonably configuring the second, third, and fourth lens elements, thereby improving the imaging quality.

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 diagram of the optical imaging system 100 in the first embodiment, and the optical imaging 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. 2 is a graph of spherical aberration, astigmatism and distortion of the optical imaging system 100 in the first embodiment sequentially from left to right, wherein the astigmatism graph and the distortion graph are both graphs at 555nm, and the other embodiments are the same.

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

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

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

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

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

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

the object-side surface S7 of the fourth lens element L4 is concave at paraxial region and concave at peripheral region;

the image-side surface S8 of the fourth lens element L4 is convex at paraxial region and convex at peripheral region;

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

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

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

It should be noted that, in the present application, when a surface of a lens is described as being convex at the optical axis (the central region of the side), it is understood that the region of the surface of the lens near the optical axis is convex, and thus the surface can also be considered as being convex at the paraxial region. When a surface of a lens is described as concave at the circumference, it is understood that the surface is concave near the region of maximum effective radius. For example, when the surface is convex at the optical axis and also convex at the circumference, the shape of the surface from the center (optical axis) to the edge direction may be purely convex; or a convex shape at the center is firstly transited to a concave shape, and then becomes a convex shape near the maximum effective radius. Here, examples are made only to illustrate the relationship at the optical axis and at the circumference, and various shape structures (concave-convex relationship) of the surface are not fully embodied, but other cases can be derived from the above examples.

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

Further, the optical imaging system 100 satisfies the relation: CT1/TTL is 0.220; the CT1 is the center thickness of the first lens L1, and the TTL is the distance from the object-side surface S1 of the first lens L1 to the image plane S13 of the optical imaging system 100 on the optical axis. Satisfying the above conditional expression, the optical imaging system 100 has the thicker first lens L1, and when the lenses are arranged in the shape, the depth of the optical imaging system 100 is increased, and the ultra-small head shape with a small outer diameter is manufactured, so that the optical imaging system can be easily matched with electronic devices such as a full-screen mobile phone.

The optical imaging system 100 satisfies the relation: ET1 ═ 0.8; ET1 is the thickness of the edge of the first lens L1, i.e. the thickness of the first lens L1 at the maximum effective clear aperture, and ET1 is expressed in mm. Satisfying the above conditional expression, the first lens L1 is thick enough to ensure that the optical imaging system 100 has a large depth, so that the front end of the lens can better match with electronic devices such as a full-face screen mobile phone.

The optical imaging system 100 satisfies the relation: CT1/ImgH ═ 0.304; wherein CT1 is the center thickness of the first lens L1, and ImgH is half of the diagonal length of the effective pixel area of the optical imaging system 100. When the above conditional expressions are satisfied, under the condition of matching chips of the same size, the larger the thickness of the first lens L1 is, the closer the object side surface S1 of the first lens L1 is to the image surface S13 of the optical imaging system 100, and when the depth requirement of the optical imaging system 100 is satisfied, the sufficient edge thickness of the first lens L1 can be ensured to bear against the lens barrel, so that the assembly stability of the optical imaging system 100 is high, and the processing manufacturability is good.

The optical imaging system 100 satisfies the relation: r10/f ═ 0.264; where R10 is the curvature radius of the image-side surface S10 of the fifth lens L5 at the paraxial region, and f is the total effective focal length of the optical imaging system 100. When the above conditional expressions are satisfied, the image-side surface S10 of the fifth lens element L5 is concave at the paraxial region, so as to provide negative refractive power, adjust the back focal length, effectively correct curvature of field, and improve the imaging quality.

The optical imaging system 100 satisfies the relation: FNO 2.55; wherein FNO is the f-number of the optical imaging system 100. When the above conditional expressions are satisfied, the optical imaging system 100 has a proper clear aperture, which not only satisfies the requirement of the clear light amount of the optical imaging system 100, but also considers that the diameter of the entrance pupil is not too large, ensures that the lens head has a smaller outer diameter, satisfies the appearance requirement of a super-small head, and is easier to match with electronic devices such as a full-screen mobile phone.

The optical imaging system 100 satisfies the relation: SD1/ImgH ═ 0.238; wherein SD1 is the maximum effective radius of the object-side surface S1 of the first lens L1, and ImgH is half the length of the diagonal line of the optical imaging system 100 in the effective pixel area. When the conditional expression is met, the ratio of SD1/ImgH is reasonably configured, so that the design of a small outer diameter of the lens head can be considered when a high-pixel large-size chip is matched.

The optical imaging system 100 satisfies the relation: CT1/OAL is 0.293; the OAL is a distance on the optical axis from the object-side surface S1 of the first lens L1 to the image-side surface S10 of the fifth lens L5. When the above conditional expressions are satisfied, the thickness of the first lens L1 is large, the optical imaging system 100 has a deep depth, and the first lens L1 can fully bear against the lens barrel, so that the assembly stability of the optical imaging system 100 is high, and the processing manufacturability is good.

The optical imaging system 100 satisfies the relation: tan (ω/2) ═ 0.8; where ω is the maximum field angle of the optical imaging system 100. When the above conditional expressions are satisfied, the optical imaging system 100 has a sufficiently large angle of view, and can satisfy the user's photographing experience when used in an electronic device having a camera function.

The optical imaging system 100 satisfies the relation: f1/f234 ═ 1.123; wherein f1 is the effective focal length of the first lens L1, and f234 is the combined focal length of the second lens L2, the third lens L3 and the fourth lens L4. When the above conditional expressions are satisfied, the first lens element L1 provides a large positive refractive power, and the spherical aberration generated by the first lens element L1 can be effectively corrected by reasonably configuring the second, third, and fourth lens elements, thereby improving the imaging quality.

In addition, the parameters of the optical imaging system 100 are given in table 1. Here, the image plane S13 in table 1 can be understood as an imaging plane of the optical imaging system 100, and as shown in fig. 15, when the optical imaging system 100 is used on the image capturing module 200, the image plane S13 can also be understood as a photosensitive surface of the photosensitive element 210. The elements from the object plane (not shown) to the image plane S13 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 surface or the image-side surface of the corresponding surface number at the optical axis. Surface number 1 and surface number 2 are the object-side surface S1 and the image-side surface S2 of the first lens L1, respectively, that is, in the same lens, 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. The first numerical value in the "thickness" parameter column of the first lens element L1 is the axial thickness of the lens element, and the second numerical value is the axial distance from the image-side surface of the lens element to the object-side surface of the following lens element in the image-side direction.

Note that, in this embodiment and the following embodiments, the optical imaging system 100 may not be provided with the infrared filter L6, but the distance from the image-side surface S10 to the image surface S13 of the fifth lens L5 is kept constant at this time.

In the first embodiment, the effective focal length f of the optical imaging system 100 is 4.04mm, the maximum field angle ω is 77.5 degrees, and the distance TTL on the optical axis from the object-side surface S1 to the image surface S13 of the first lens L1 is 4.6 mm.

The focal length, refractive index, and abbe number of each lens are values at a wavelength of 555nm, and the same applies to other examples.

TABLE 1

Further, aspheric coefficients of the image-side surface or the object-side surface of each lens of the optical imaging system 100 are given in table 2. Wherein, the surface numbers represent the image side or the object side S1-S10 from 1-10, respectively. And K-a20 from top to bottom respectively indicate the types of aspheric coefficients, where K indicates a conic constant, a4 indicates a quartic aspheric coefficient, a6 indicates a sextic aspheric coefficient, A8 is an eighth 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 aspherical surface to a plane tangent to the surface vertex, r is the distance from the corresponding point on the aspherical surface to the optical axis, c is the curvature of the aspherical surface vertex, k is a conic constant, and Ai is a coefficient corresponding to the i-th high order term in the aspherical surface type formula, such as a4, a6, or A8.

TABLE 2

Second embodiment

Referring to fig. 3 and 4, fig. 3 is a schematic diagram of the optical imaging system 100 in the second embodiment, in which the optical imaging 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. 4 is a graph illustrating the spherical aberration, astigmatism and distortion of the optical imaging system 100 according to the second embodiment from left to right.

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

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

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

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

In addition, the parameters of the optical imaging 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 imaging system 100 are given in table 4, and the definitions of the parameters can be obtained from the first embodiment, which is not repeated herein.

TABLE 4

Furthermore, according to the provided parameter information, the following relationship can be deduced:

CT1/TTL＝0.226；ET1＝0.715；CT1/ImgH＝0.347；R10/f＝0.239；FNO＝2.32；

SD1/ImgH＝0.257；CT1/OAL＝0.286；tan(ω/2)＝0.838；f1/f234＝1.391。

third embodiment

Referring to fig. 5 and 6, fig. 5 is a schematic diagram of the optical imaging system 100 in the third embodiment, in which the optical imaging 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 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 of spherical aberration, astigmatism and distortion of the optical imaging system 100 in the third embodiment, from left to right.

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

the object-side surface S7 of the fourth lens element L4 is convex at paraxial region and concave at peripheral region;

the image-side surface S8 of the fourth lens element L4 is concave at paraxial region and convex at peripheral region;

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

In addition, the parameters of the optical imaging 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.

TABLE 5

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

TABLE 6

CT1/TTL＝0.190；ET1＝0.686；CT1/ImgH＝0.250；R10/f＝0.628；FNO＝3；

SD1/ImgH＝0.183；CT1/OAL＝0.227；tan(ω/2)＝0.902；f1/f234＝0.373。

fourth embodiment

Referring to fig. 7 and 8, fig. 7 is a schematic diagram of the optical imaging system 100 in the fourth embodiment, in which the optical imaging 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. 8 is a graph of spherical aberration, astigmatism and distortion of the optical imaging system 100 in the fourth embodiment, which is shown from left to right.

In addition, the parameters of the optical imaging 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 imaging system 100 are given in table 8, and the definitions of the parameters can be obtained from the first embodiment, which is not repeated herein.

TABLE 8

CT1/TTL＝0.260；ET1＝1；CT1/ImgH＝0.365；R10/f＝0.239；FNO＝2.45；

SD1/ImgH＝0.229；CT1/OAL＝0.338；tan(ω/2)＝0.869；f1/f234＝1.779。

fifth embodiment

Referring to fig. 9 and 10, fig. 9 is a schematic diagram of the optical imaging system 100 in the fifth embodiment, in which the optical imaging 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 L ]3 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 illustrating spherical aberration, astigmatism and distortion of the optical imaging system 100 according to the fifth embodiment from left to right.

In addition, the parameters of the optical imaging 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 imaging system 100 are given in table 10, and the definitions of the parameters can be obtained from the first embodiment, which is not repeated herein.

Watch 10

CT1/TTL＝0.223；ET1＝0.555；CT1/ImgH＝0.265；R10/f＝0.267；FNO＝2.24；

SD1/ImgH＝0.241；CT1/OAL＝0.237；tan(ω/2)＝0.933；f1/f234＝1.718。

sixth embodiment

Referring to fig. 11 and 12, fig. 11 is a schematic diagram of the optical imaging system 100 in the sixth embodiment, in which the optical imaging 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. 12 is a graph illustrating spherical aberration, astigmatism and distortion of the optical imaging system 100 according to the sixth embodiment from left to right.

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

In addition, the parameters of the optical imaging system 100 are given in table 11, and the definitions of the parameters can be obtained from the first embodiment, which is not described herein.

TABLE 11

Further, the aspheric coefficients of the image-side surface or the object-side surface of each lens of the optical imaging system 100 are given in table 12, and the definitions of the parameters can be obtained from the first embodiment, which is not repeated herein.

TABLE 12

CT1/TTL＝0.196；ET1＝0.680；CT1/ImgH＝0.257；R10/f＝0.378；FNO＝2.45；

SD1/ImgH＝0.222；CT1/OAL＝0.244；tan(ω/2)＝0.878；f1/f234＝0.843。

seventh embodiment

Referring to fig. 13 and 14, fig. 13 is a schematic diagram of the optical imaging system 100 in the seventh embodiment, in which the optical imaging 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 negative refractive power, a fourth lens element L4 with positive refractive power, and a fifth lens element L5 with negative refractive power. Fig. 14 is a graph illustrating spherical aberration, astigmatism and distortion of the optical imaging system 100 according to the seventh embodiment from left to right.

In addition, the parameters of the optical imaging system 100 are given in table 13, and the definitions of the parameters can be obtained from the first embodiment, which is not described herein.

Watch 13

Further, the aspheric coefficients of the image-side surface or the object-side surface of each lens of the optical imaging system 100 are given in table 14, and the definition of each parameter can be derived from the first embodiment, which is not described herein again.

TABLE 14

CT1/TTL＝0.240；ET1＝0.897；CT1/ImgH＝0.329；R10/f＝0.371；FNO＝2.54；

SD1/ImgH＝0.227；CT1/OAL＝0.301；tan(ω/2)＝0.854；f1/f234＝0.813。

referring to fig. 15, in some embodiments, the optical imaging system 100 may be assembled with the photosensitive element 210 to form the image capturing module 200. At this time, the image plane S13 of the optical imaging system 100 can be regarded as the photosensitive plane of the photosensitive element 210. The image capturing module 200 may further include an infrared filter L6, and the infrared filter L6 is disposed between the image side surface S10 and the image surface S13 of the fifth lens element L5. Specifically, the photosensitive element 210 may be a Charge Coupled Device (CCD) or a Complementary Metal-Oxide Semiconductor (CMOS) element. The optical imaging system 100 is adopted in the image capturing module 200, so that the image capturing module has high pixels and good imaging quality, and is favorable for small outer diameter of the manufactured lens head and deep depth of the optical imaging system 100.

Referring to fig. 16, in some embodiments, the image capturing module 200 may be used in an electronic device 300, the electronic device includes a housing 310, and the image capturing module 200 is mounted on the housing 310. Specifically, the electronic apparatus 300 may be a portable phone, a video phone, a smart phone, an electronic book reader, a drive recorder, or a wearable device. Since the lens head made of the image capturing module 200 has a small outer diameter and the depth of the optical imaging system 100 is deep, the image capturing module 200 is adopted in the electronic device 300, so that the imaging quality is good, and the lens head is easier to be installed in the housing 310.

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 invention. 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 imaging system, comprising, in order from an object side to an image side:

the second lens element with refractive power has a concave image-side surface;

a third lens element with refractive power;

a fourth lens element with refractive power;

and the optical imaging system satisfies the following conditional expression:

CT1/TTL≥0.19；

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

ET1≥0.555；

wherein ET1 is the edge thickness of the first lens, and ET1 has the unit of mm.

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

CT1/ImgH≥0.25；

wherein ImgH is half of the diagonal length of the effective pixel area of the optical imaging system.

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

0.2＜R10/f＜0.7；

wherein R10 is a radius of curvature of an image-side surface of the fifth lens element at a paraxial region, and f is an overall effective focal length of the optical imaging system.

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

2.2≤FNO≤3.0；

wherein FNO is an f-number of the optical imaging system.

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

SD1/ImgH＜0.26；

wherein SD1 is the maximum effective radius of the object side surface of the first lens, and ImgH is half of the diagonal length of the optical imaging system in the effective pixel area.

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

CT1/OAL＞0.22；

and the OAL is the distance from the object side surface of the first lens to the image side surface of the fifth lens on the optical axis.

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

tan(ω/2)＜1.0；

where ω is the maximum field angle of the optical imaging system.

9. The optical imaging system of claim 1, wherein the following conditional expression is satisfied:

0.3＜f1/f234＜2；

wherein f1 is the effective focal length of the first lens, and f234 is the combined focal length of the second lens, the third lens and the fourth lens.

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

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