CN111830676A

CN111830676A - Optical system, image capturing module and electronic device

Info

Publication number: CN111830676A
Application number: CN202010667662.XA
Authority: CN
Inventors: 杨健; 李明; 邹海荣
Original assignee: OFilm Tech Co Ltd
Current assignee: OFilm Group Co Ltd
Priority date: 2020-07-13
Filing date: 2020-07-13
Publication date: 2020-10-27

Abstract

The application relates to an optical system, an image capturing module and an electronic device. The optical system sequentially comprises a first lens with refractive power from an object side to an image side along an optical axis, wherein the object side surface of the first lens is concave at a paraxial region; the second lens element with negative refractive power has a concave image-side surface at the paraxial region; a third lens element with positive refractive power having a convex object-side surface at the paraxial region and a convex image-side surface at the paraxial region; a fourth lens element with negative refractive power having a concave image-side surface at the paraxial region; a fifth lens element with refractive power; a sixth lens element with refractive power; a seventh lens element with refractive power; and an eighth lens element with negative refractive power having a concave image-side surface at the paraxial region. The optical system described above can balance the expansion of the field angle range, high-quality imaging, and miniaturization when satisfying a specific relationship.

Description

Optical system, image capturing module and electronic device

Technical Field

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

Background

In recent years, portable electronic products such as mobile phones with a camera function are rapidly reformed, and the arrangement modes of screen structures such as a water drop screen and a bang screen are diversified, so that higher requirements are put forward on matched camera lenses. On the other hand, the photosensitive element of the lens module includes two types, namely a Charge Coupled Device (CCD) and a Complementary Metal-Oxide Semiconductor (CMOS) element, and with the development of the photosensitive element technology, the pixel size of the chip is smaller and smaller, and the imaging quality requirement for the matched lens is higher and higher.

Although the conventional optical system can obtain a large-angle shooting range and high imaging quality by increasing the number of lenses, the total length of the system is difficult to control, the lens module is easy to enlarge, and the system is not suitable for portable electronic equipment with limited size such as a mobile phone and a tablet.

Disclosure of Invention

In view of the above, there is a need for an improved optical system, which is difficult to balance the wide viewing angle, high imaging quality and miniaturization of the conventional optical system.

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

the optical lens comprises a first lens element with refractive power, wherein the object-side surface of the first lens element is concave at the paraxial region;

the second lens element with negative refractive power has a concave image-side surface at the paraxial region;

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

a fourth lens element with negative refractive power having a concave image-side surface at a paraxial region;

a fifth lens element with refractive power;

a sixth lens element with refractive power;

a seventh lens element with refractive power; and the number of the first and second groups,

an eighth lens element with negative refractive power having a concave image-side surface at the paraxial region;

the optical system satisfies the following relation:

-1.8＜f₁₂/f₃₄₅₆₇₈＜-0.5；

wherein f is₁₂Denotes a combined focal length of the first lens and the second lens, f₃₄₅₆₇₈Represents a combined focal length of the third lens to the eighth lens.

According to the optical system, the imaging analysis capability of the lens can be enhanced and the aberration can be effectively corrected by selecting a proper number of lenses and reasonably distributing the refractive power and the surface type of each lens, so that the definition of an image is ensured; in addition, when the relation is met, the refractive power of the front lens group and the rear lens group of the system can be reasonably distributed, so that chromatic aberration of the system can be better corrected, and the imaging performance of the system is improved.

In one embodiment, the object-side surface and the image-side surface of each of the first lens to the eighth lens are aspheric.

By the method, the flexibility of lens design can be improved, for example, edge aberration can be effectively corrected by setting an inflection point, and the imaging quality of an optical system is improved; meanwhile, the lens can realize excellent optical imaging effect under the conditions of small size, thinness and flatness, so that the optical system has the characteristic of miniaturization.

In one embodiment, the optical system satisfies the following relationship: TTL/ImgH is less than 2.8; wherein, TTL represents a distance on an optical axis from an object-side surface of the first lens element to an image plane of the optical system, and ImgH represents an image height corresponding to half of a maximum field angle of the optical system.

When the relation is satisfied, the total length of the system is not too large under the condition that the image plane is fixed, so that the total length of the system is favorably and properly shortened, and the miniaturization of the optical system is ensured.

In one embodiment, the optical system satisfies the following relationship: TTL/f is less than 4.5; wherein, TTL represents a distance on an optical axis from an object-side surface of the first lens element to an image plane of the optical system, and f represents an effective focal length of the optical system.

When the relation is met, the total length of the system can be reasonably configured under the condition that the effective focal length of the system is fixed, so that the total length of the system is not too large, and the miniaturization requirement of the system is met.

In one embodiment, the optical system satisfies the following relationship: f/RS16 is more than 0.3 and less than 2; where f denotes an effective focal length of the optical system, and RS16 denotes a radius of curvature of an image-side surface of the eighth lens at an optical axis.

When satisfying above-mentioned relation, the image side of the rational arrangement eighth lens in the radius of curvature of optical axis department helps reducing the exit angle when the light is jetted out from the image side of the eighth lens to the chief ray incident angle when can effectively suppress the light and incide to the photosensitive element strengthens the photosensitive property of photosensitive element, promotes the power of resolving a picture of camera lens module.

In one embodiment, the optical system satisfies the following relationship: FNO is less than 2.6; wherein FNO denotes an f-number of the optical system.

When the above relation is satisfied, it is advantageous to provide a system with a large aperture while maintaining the miniaturization of the system, thereby increasing the amount of light transmitted per unit time of the system and improving the dim light photographing capability of the system.

In one embodiment, the optical system satisfies the following relationship: f/f3 is more than 0.4 and less than 1.2; where f denotes an effective focal length of the optical system, and f3 denotes an effective focal length of the third lens.

When satisfying above-mentioned relation, can rationally dispose the effective focal length of third lens under the fixed circumstances of system effective focal length to help the axle of balanced system better to color the difference, promote the epaxial performance of system.

In one embodiment, the optical system satisfies the following relationship:

0 < (RS5+ RS6)/(RS5-RS6) < 1; wherein RS5 denotes a radius of curvature of an object-side surface of the third lens at an optical axis, and RS6 denotes a radius of curvature of an image-side surface of the third lens at the optical axis.

When the above relationship is satisfied, the curvature radii of the object-side surface and the image-side surface of the third lens element at the optical axis can be reasonably configured, so that it is favorable for ensuring that the third lens element provides positive refractive power for the system, balancing the refractive power of the other lens elements in the system, better correcting the aberration of the system, and improving the imaging performance of the system.

In one embodiment, the optical system satisfies the following relationship: tan (HFOV) > 2; wherein the HFOV represents a half of a maximum angle of view of the optical system.

When the relation is satisfied, the half field angle of the system in the diagonal direction can be reasonably configured, so that the system has a wider field angle range and meets the imaging requirement of a wide angle.

The application also provides an image capturing module.

An image capturing module includes the optical system and a photosensitive element, wherein the photosensitive element is disposed at an image side of the optical system.

The image capturing module can shoot images with wide visual angles and high pixels by utilizing the optical system, has the structural characteristics of miniaturization and light weight, is convenient to adapt to devices with limited sizes such as mobile phones and flat plates, and meets market requirements.

The application also provides an electronic device.

An electronic device comprises a shell and the image capturing module, wherein the image capturing module is arranged on the shell.

Above-mentioned electronic device has lightweight characteristics, and utilizes aforementioned get for instance the module and can shoot and obtain the wide, the high image of pixel of visual angle, and then promotes user's shooting experience.

Drawings

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

fig. 2 shows a longitudinal spherical aberration graph, an astigmatism graph, and a distortion graph, respectively, of the optical system of example 1;

fig. 3 is a schematic structural view showing an optical system of embodiment 2 of the present application;

fig. 4 shows a longitudinal spherical aberration graph, an astigmatism graph, and a distortion graph, respectively, of the optical system of example 2;

fig. 5 is a schematic structural view showing an optical system of embodiment 3 of the present application;

fig. 6 shows a longitudinal spherical aberration graph, an astigmatism graph, and a distortion graph, respectively, of the optical system of example 3;

fig. 7 is a schematic structural view showing an optical system of embodiment 4 of the present application;

fig. 8 shows a longitudinal spherical aberration graph, an astigmatism graph, and a distortion graph, respectively, of the optical system of example 4;

fig. 9 is a schematic structural view showing an optical system of embodiment 5 of the present application;

fig. 10 shows a longitudinal spherical aberration graph, an astigmatism graph, and a distortion graph, respectively, of the optical system of example 5;

fig. 11 is a schematic structural view showing an optical system of embodiment 6 of the present application;

fig. 12 shows a longitudinal spherical aberration graph, an astigmatism graph, and a distortion graph, respectively, of the optical system of example 6;

fig. 13 is a schematic structural view showing an optical system of embodiment 7 of the present application;

fig. 14 shows a longitudinal spherical aberration graph, an astigmatism graph, and a distortion graph, respectively, of the optical system of example 7;

fig. 15 is a schematic structural view showing an optical system of embodiment 8 of the present application;

fig. 16 shows a longitudinal spherical aberration graph, an astigmatism graph, and a distortion graph, respectively, of the optical system of example 8;

fig. 17 is a schematic structural view showing an optical system of embodiment 9 of the present application;

fig. 18 shows a longitudinal spherical aberration chart, an astigmatism chart, and a distortion chart, respectively, of the optical system of example 9;

fig. 19 is a schematic diagram illustrating an image capturing module according to an embodiment of the present application;

fig. 20 is a schematic view illustrating an electronic device using an image capturing module according to an embodiment of the disclosure.

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. As used herein, the terms "vertical," "horizontal," "left," "right," "upper," "lower," "front," "rear," "circumferential," and the like are based on the orientation or positional relationship shown in the drawings for ease of description and simplicity of description, and do not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting of the present invention.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

In the present description, the expressions first, second, third and the like are used only for distinguishing one feature from another feature, and do not indicate any limitation on the features. Thus, the first lens discussed below may also be referred to as the second lens or the third lens without departing from the teachings of the present application. For ease of illustration, the shapes of the spherical or aspherical surfaces shown in the drawings are shown by way of example. That is, the shape of the spherical surface or the aspherical surface is not limited to the shape of the spherical surface or the aspherical surface shown in the drawings. The figures are purely diagrammatic and not drawn to scale.

In this specification, a space on a side of the optical element where the object is located is referred to as an object side of the optical element, and correspondingly, a space on a side of the optical element where the object is located is referred to as an image side of the optical element. The surface of each lens closest to the object is called the object side surface, and the surface of each lens closest to the image plane is called the image side surface. And defines the positive direction with distance from the object side to the image side.

In addition, in the following description, if it appears that a lens surface is convex and the convex position is not defined, it means that the lens surface is convex at least near the optical axis; if the lens surface is concave and the concave position is not defined, it means that the lens surface is concave at least at the position near the optical axis. Here, the paraxial region means a region near the optical axis. Specifically, the irregularity of the lens surface region is determined on the image side or the object side by the intersection point of the light ray passing through the region in parallel with the optical axis. For example, when the parallel light passes through the region, the light is focused toward the image side, and the intersection point of the light and the optical axis is located at the image side, the region is a convex surface; on the contrary, if the light ray passes through the region, the light ray is diverged, and the intersection point of the extension line of the light ray and the optical axis is at the object side, the region is a concave surface. In addition, the lens includes an optical axis vicinity region, a circumference vicinity region, and an extension portion for fixing the lens. Ideally, the imaging light does not pass through the extension portion, and therefore the range from the region near the optical axis to the region near the circumference can be defined as the effective aperture range of the lens. The following embodiments omit portions of the extensions for clarity of the drawings. Further, the method of determining the range of the optical axis vicinity region, the circumference vicinity region, or the plurality of regions is as follows:

first, a central point is defined as an intersection point of the lens surface and the optical axis, the distance from the central point to the boundary of the effective aperture range of the lens is the effective semi-aperture of the lens, and a point of inflection is located on the lens surface and is not located on the optical axis, and a tangent line passing through the point of inflection is perpendicular to the optical axis (i.e. the surface types of both sides of the point of inflection on the lens surface are opposite). If there are several points of inflection from the central point to the outside in the radial direction of the lens, the points of inflection are the first point of inflection and the second point of inflection in sequence, and the point of inflection farthest from the central point in the effective aperture range of the lens is the Nth point of inflection. Defining the range between the central point and the first inflection point as an area near the optical axis, defining an area radially outward of the Nth inflection point as an area near the circumference, and dividing the area between the first inflection point and the Nth inflection point into different areas according to the inflection points; if there is no inflection point on the lens surface, the region near the optical axis is defined as a region corresponding to 0 to 50% of the effective half-aperture, and the region near the circumference is defined as a region corresponding to 50 to 100% of the effective half-aperture.

The features, principles and other aspects of the present application are described in detail below.

Referring to fig. 1, fig. 3, fig. 5, fig. 7, fig. 9, fig. 11, fig. 13, fig. 15, and fig. 17, an optical system with wide viewing angle, high pixel and miniaturization is provided in the present embodiment. The optical system includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens. The eight lens elements are arranged along an optical axis from the object side to the image side in sequence from the first lens element to the eighth lens element, and an image plane of the optical system is located at the image side of the eighth lens element.

Specifically, the first lens element with refractive power has a concave object-side surface near the optical axis, so that large-angle light can enter the system, and the field of view of the optical system is enlarged;

the second lens element with negative refractive power has a concave image-side surface near the optical axis, which is beneficial to increasing the width of incident light, so that the light with large angle incidence can be further widened after being refracted and converted by the first lens element, thereby filling the pupil, fully transmitting to the high-pixel image surface and obtaining a wider field range.

The third lens element with positive refractive power has a convex object-side surface at the paraxial region and a convex image-side surface at the paraxial region. Because the first lens element and the second lens element provide negative refractive power for the system as a whole, the negative refractive power of the front lens element can be balanced to correct the peripheral aberration by providing a third lens element with positive refractive power, and the overall refractive power of the system can be balanced to better correct the system aberration and chromatic aberration, thereby improving the imaging performance of the system.

The fourth lens element with negative refractive power has a concave image-side surface at the paraxial region, so that the configuration of the refractive power can be effectively dispersed, excessive aberration can be avoided, and the imaging quality can be further improved.

The fifth lens element with refractive power, the sixth lens element with refractive power, and the seventh lens element with refractive power. Through the arrangement of the fifth lens, the sixth lens and the seventh lens with refractive power, collected image information can be effectively transmitted to an imaging surface, chromatic aberration of the system is effectively balanced through reasonable refractive power distribution, and imaging performance of the system is improved.

The eighth lens element with negative refractive power can cooperate with the third, fourth, fifth, sixth and seventh lens elements to balance the refractive powers of the first and second lens elements, so that the refractive powers of the front and rear portions of the system can be reasonably distributed, thereby better correcting chromatic aberration of the system and improving imaging performance of the system. Meanwhile, the near optical axis of the image side surface of the eighth lens is a concave surface, so that the incident angle of a chief ray on the photosensitive element can be suppressed, the photosensitive performance of the photosensitive element can be improved, and the resolution of the system can be improved.

Further, the optical system satisfies the following relation: -1.8 < f₁₂/f₃₄₅₆₇₈< -0.5; wherein f is₁₂Denotes the combined focal length of the first lens and the second lens, f₃₄₅₆₇₈Denotes a combined focal length of the third lens to the eighth lens. f. of₁₂/f₃₄₅₆₇₈Can be-1.5, -1.4, -1.3, -1.33, -1.32, -1.31, -1.3, -1.29, -1.28, -1.24, -1.2 or-1. When the relation is met, the refractive power of the front lens group and the rear lens group of the system can be reasonably distributed, so that chromatic aberration of the system can be corrected better, and the imaging performance of the system is improved. When f is₁₂/f₃₄₅₆₇₈When the refractive power distribution is higher than the upper limit or lower than the lower limit, the refractive power distribution of the front and rear lens groups of the system is unbalanced, which is not favorable for correcting the chromatic aberration of the system and reduces the imaging quality of the system.

When the optical system is used for imaging, light rays emitted or reflected by a shot object enter the optical system from the object side direction, sequentially pass through the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens, and finally converge on an imaging surface.

According to the optical system, the imaging analysis capability of the lens can be enhanced and the aberration can be effectively corrected by selecting a proper number of lenses and reasonably distributing the refractive power and the surface type of each lens, so that the resolution of the lens is improved, and the definition of an image is ensured; meanwhile, when the effective focal lengths of the first lens to the eighth lens meet a specific relation, chromatic aberration of the system can be corrected better, and imaging performance of the system can be improved.

In an exemplary embodiment, the object-side surface and the image-side surface of the first lens to the eighth lens are each aspheric. The aspheric lens is characterized in that: the curvature is continuously varied from the lens center to the lens periphery, and the aspherical lens has a better curvature radius characteristic, unlike a spherical lens having a constant curvature from the lens center to the lens periphery, and has an advantage of improving peripheral aberration and astigmatic field curvature. By the mode, the flexibility of lens design can be improved, aberration can be effectively corrected, and the imaging quality of the optical system can be improved. The object side surface and the image side surface of the first lens, the second lens and the eighth lens are both set to be aspheric surfaces, so that aberration generated in the light transmission process can be corrected better. It should be noted that the surface of each lens may be any combination of a spherical surface and an aspherical surface without departing from the technical solution of the optical system of the present application, and the present application is not limited thereto.

In an exemplary embodiment, the optical system satisfies the following relationship: TTL/ImgH is less than 2.8; wherein, TTL represents a distance on the optical axis from the object-side surface of the first lens element to the image plane of the optical system, and ImgH represents an image height corresponding to half of the maximum field angle of the optical system. Further, in the present application, half of the maximum field angle refers to the angle that the ray incident at the maximum viewing angle makes with the optical axis of the lens, TTL/ImgH can be 2.2, 2.3, 2.34, 2.38, 2.382, 2.384, 2.388, 2.392, 2.396, 2.5, or 2.7. When the relation is satisfied, the total length of the system is not too large under the condition that the image plane is fixed, so that the total length of the system is favorably and properly shortened, and the miniaturization of the optical system is ensured. When TTL/ImgH exceeds the upper limit, the total length of the system is easy to be overlong, which is not beneficial to miniaturization.

In an exemplary embodiment, the optical system satisfies the following relationship: TTL/f is less than 4.5; wherein, TTL denotes a distance on the optical axis from the object side surface of the first lens element to the imaging surface of the optical system, and f denotes an effective focal length of the optical system. TTL/f can be 4, 4.02, 4.04, 4.06, 4.08, 4.1, 4.12, 4.14, 4.2, 4.3, or 4.4. When the relation is met, the total length of the system can be reasonably configured under the condition that the effective focal length of the system is fixed, so that the total length of the system is not too large, and the miniaturization requirement of the system is met. And when the TTL/f exceeds the upper limit, the total length of the system is too long, which is not beneficial to miniaturization.

In an exemplary embodiment, the optical system satisfies the following relationship: f/RS16 is more than 0.3 and less than 2; where f denotes an effective focal length of the optical system, and RS16 denotes a radius of curvature of the image-side surface of the eighth lens at the optical axis. f/RS16 can be 0.4, 0.6, 0.8, 0.85, 0.9, 0.95, 1.0, 1.05, 1.1, 1.2, 1.3, 1.35, 1.4, 1.5, or 1.8. When satisfying above-mentioned relation, the image side that can rational configuration eighth lens is at the radius of curvature of optical axis department, helps reducing the exit angle when light jets out from eighth lens image side to the chief ray incident angle when can effectively suppressing light and incidenting to the sensitization chip strengthens the sensitization performance of sensitization chip, promotes the power of resolving a picture of camera lens module. When the f/RS16 is lower than the lower limit, the curvature radius of the image side surface of the eighth lens at the optical axis is too large, which is not favorable for reducing the emergent angle of the light emitted from the image side surface of the eighth lens, and is further not favorable for matching with the incident angle of the main light of the photosensitive chip; when the f/RS16 exceeds the upper limit, the curvature radius of the image side surface of the eighth lens at the optical axis is too small, the preparation difficulty of the single lens is increased, and the effective focal length of the system is easily too large at the moment, which is not beneficial to wide-angle.

In an exemplary embodiment, the optical system satisfies the following relationship: FNO is less than 2.6; wherein FNO denotes an f-number of the optical system. The FNO may be 1.9, 1.95, 2, 2.05, 2.1, 2.15, 2.2, 2.25, 2.3, 2.4, or 2.5. When the above relation is satisfied, it is advantageous to provide a system with a large aperture while maintaining the miniaturization of the system, thereby increasing the amount of light transmitted per unit time of the system and improving the dim light photographing capability of the system. When the FNO exceeds the upper limit, the aperture of the system is small, the light flux of the system is low, the image surface brightness is low, and the shooting in a dark environment is not facilitated.

In an exemplary embodiment, the optical system satisfies the following relationship: f/f3 is more than 0.4 and less than 1.2; where f denotes an effective focal length of the optical system, and f3 denotes an effective focal length of the third lens. f/f3 may be 0.5, 0.6, 0.7, 0.75, 0.8, 0.82, 0.84, 0.86, 0.88, 0.9, 0.95, 1.0, or 1.1. When satisfying above-mentioned relation, can rationally dispose the effective focal length of third lens under the fixed circumstances of system effective focal length to help the axle of balanced system better to color the difference, promote the epaxial performance of system. When the f/f3 is lower than the lower limit or higher than the upper limit, the refractive power of the third lens element is too low or too high, which is not favorable for the refractive power of the balance system, and thus is not favorable for the on-axis aberration of the balance system and the image quality is reduced.

In an exemplary embodiment, the optical system satisfies the following relationship:

0 < (RS5+ RS6)/(RS5-RS6) < 1; wherein RS5 denotes a radius of curvature of the object-side surface of the third lens at the optical axis, and RS6 denotes a radius of curvature of the image-side surface of the third lens at the optical axis. (RS5+ RS6)/(RS5-RS6) may be 0.2, 0.22, 0.24, 0.26, 0.28, 0.3, 0.33, 0.36, 0.39, 0.42, 0.5 or 0.8. When the above relationship is satisfied, the curvature radii of the object-side surface and the image-side surface of the third lens element at the optical axis can be reasonably configured, so that it is favorable for ensuring that the third lens element provides positive refractive power for the system, balancing the refractive power of the other lens elements in the system, better correcting the aberration of the system, and improving the imaging performance of the system. When the (RS5+ RS6)/(RS5-RS6) is lower than the lower limit, the image-side surface of the third lens element is too flat, so that the positive refractive power of the third lens element is insufficient, which is not favorable for balancing the refractive powers of the other lens elements in the system, and is further unfavorable for correcting the system aberration, and the imaging quality is difficult to ensure.

In an exemplary embodiment, the optical system satisfies the following relationship: tan (HFOV) > 2; the HFOV represents a half of the maximum angle of view of the optical system. tan (hfov) may be 3, 3.5, 4, 4.2, 4.4, 4.6, 4.8, 5, 5.2, 5.4, 5.8, 6.2, 6.6 or 7. When the relation is satisfied, the half field angle of the system in the diagonal direction can be reasonably configured, so that the system has a wider field angle range and meets the imaging requirement of a wide angle. When tan (hfov) is out of range, the field angle range of the system is small, and it is difficult to satisfy the requirement of wide angle of the system.

The optical system is also provided with a diaphragm so as to better control the size of an incident beam and improve the imaging quality of the optical system. Further, the diaphragm is arranged between the second lens and the third lens. Preferably, the diaphragm is an aperture diaphragm. The aperture stop may be located on a surface of the lens (e.g., the object side and the image side) and in operative relationship with the lens, for example, by applying a light blocking coating to the surface of the lens to form the aperture stop at the surface; or the surface of the clamping lens is fixedly clamped by the clamping piece, and the structure of the clamping piece on the surface can limit the width of the imaging light beam of the on-axis object point, so that the aperture stop is formed on the surface.

In an exemplary embodiment, an optical filter is further disposed between the eighth lens and the imaging surface of the optical system, and is configured to filter light in a non-operating wavelength band, so as to prevent a phenomenon of generating a false color or moire due to interference of light in a non-operating wavelength band, and avoid distortion of imaging colors. Specifically, the filter may be an infrared cut filter, and the material of the filter is glass.

In an exemplary embodiment, each lens in the optical system may be made of glass or plastic, the plastic lens can reduce the weight and production cost of the optical system, and the glass lens can provide the optical system with better temperature tolerance and excellent optical performance. Further, when the optical system is applied to a mobile phone or a tablet, the material of each lens is preferably plastic, so as to reduce the weight of the optical system and reduce the production cost on the premise of satisfying the imaging performance. It should be noted that the material of each lens in the optical system may be any combination of glass and plastic, and is not necessarily all glass or all plastic.

In an exemplary embodiment, the optical system may further include a protective glass. The protective glass is arranged at the image side of the sixth lens or the image side of the optical filter, plays a role in protecting the photosensitive element, and can also prevent the photosensitive element from being polluted and dust falling, thereby further ensuring the imaging quality. When the optical system is applied to an electronic device such as a mobile phone or a tablet, the cover glass may not be provided, so as to further reduce the weight of the electronic device.

The optical system of the above-described embodiments of the present application may employ a plurality of lenses, such as the eight lenses described above. By reasonably distributing the focal length, the refractive power, the surface shape, the thickness, the on-axis distance between the lenses and the like of each lens, the optical system has the characteristics of large field angle, small total length and high resolution, and simultaneously has larger aperture (FNO can be 1.98) and lighter weight, thereby better meeting the application requirements of electronic equipment such as mobile phones, flat plates and the like. However, it will be understood by those skilled in the art that the number of lenses constituting the optical system may be varied to obtain the respective results and advantages described in the present specification without departing from the technical solutions claimed in the present application.

Specific examples of optical systems that can be applied to the above-described embodiments are further described below with reference to the drawings. The following examples were each analyzed for aberrations using five operating wavelengths of 470nm, 510nm, 555nm, 610nm, 650nm, with 555nm being the primary reference wavelength.

Example 1

An optical system 100 of embodiment 1 of the present application is described below with reference to fig. 1 to 2.

Fig. 1 shows a schematic configuration diagram of an optical system 100 of embodiment 1. As shown in fig. 1, the optical system 100 includes, in order from an object side to an image side along an optical axis, a first lens element L1, a second lens element L2, a third lens element L3, a fourth lens element L4, a fifth lens element L5, a sixth lens element L6, a seventh lens element L7, an eighth lens element L8, and an image plane S19.

The first lens element L1 with positive refractive power has an object-side surface S1 and an image-side surface S2 that are aspheric, wherein the object-side surface S1 is concave along an optical axis and convex along a circumference, and the image-side surface S2 is convex along the optical axis and concave along the circumference.

The second lens element L2 with negative refractive power has an object-side surface S3 and an image-side surface S4 that are aspheric, wherein the object-side surface S3 is concave along the optical axis and concave along the circumference, and the image-side surface S4 is concave along the optical axis and concave along the circumference.

The third lens element L3 with positive refractive power has an object-side surface S5 and an image-side surface S6 that are aspheric, wherein the object-side surface S5 is convex along an optical axis and concave along a circumference, and the image-side surface S6 is convex along the optical axis and convex along the circumference.

The fourth lens element L4 with negative refractive power has an object-side surface S7 and an image-side surface S8 that are aspheric, wherein the object-side surface S7 is convex along the optical axis and concave along the circumference, and the image-side surface S8 is concave along the optical axis and convex along the circumference.

The fifth lens element L5 with positive refractive power has an object-side surface S9 and an image-side surface S10 that are aspheric, wherein the object-side surface S9 is convex along an optical axis and concave along a circumference, and the image-side surface S10 is convex along the optical axis and concave along the circumference.

The sixth lens element L6 with negative refractive power has an object-side surface S11 and an image-side surface S12 that are aspheric, wherein the object-side surface S11 is convex along an optical axis and concave along a circumference, and the image-side surface S12 is concave along the optical axis and convex along the circumference.

The seventh lens element L7 with positive refractive power has an object-side surface S13 and an image-side surface S14 that are aspheric, wherein the object-side surface S13 is convex along an optical axis and convex along a circumference, and the image-side surface S14 is convex along the optical axis and convex along the circumference.

The eighth lens element L8 with negative refractive power has an object-side surface S15 and an image-side surface S16 that are aspheric, wherein the object-side surface S15 is convex along the optical axis and convex along the circumference, and the image-side surface S16 is concave along the optical axis and concave along the circumference.

The object-side surface and the image-side surface of each of the first lens element L1 to the eighth lens element L8 are aspheric, which is advantageous for correcting aberrations and solving the problem of image surface distortion, and enables the lens elements to achieve excellent optical imaging effects even when the lens elements are small, thin, and flat, thereby enabling the optical system 100 to have a compact size.

The first lens L1 to the eighth lens L8 are all made of plastic, and the use of plastic lenses can reduce the weight of the optical system 100 and reduce the production cost.

A stop STO is further disposed between the second lens L2 and the third lens L3 to limit the size of an incident light beam, and further improve the imaging quality of the optical system 100. The optical system 100 further includes a filter 110 disposed on the image side of the eighth lens L8 and having an object-side surface S17 and an image-side surface S18. Light from the object OBJ sequentially passes through the respective surfaces S1 to S18 and is finally imaged on the imaging plane S19. The optical filter 110 is used for filtering the light rays in the non-working wavelength band, thereby preventing the phenomenon of generating false color or moire caused by the interference of the light rays in the non-working wavelength band, and avoiding the distortion of the imaging color. Specifically, the filter 110 is an infrared cut filter, and is made of glass.

Table 1 shows the surface type, radius of curvature, thickness, material, refractive index, abbe number (i.e., abbe number), and effective focal length of the lens of the optical system 100 of example 1, where the reference wavelength of refractive index and abbe number is 587.56nm, the reference wavelength of effective focal length is 555nm, and the unit of radius of curvature, thickness, and effective focal length of the lens is millimeters (mm). In addition, taking the first lens element L1 as an example, the first numerical value in the "thickness" parameter sequence of the first lens element L1 is the thickness of the lens element on the optical axis, and the second numerical value is the distance between the image-side surface of the lens element and the object-side surface of the subsequent lens element in the image-side direction; the numerical value of the stop ST0 in the "thickness" parameter column is the distance on the optical axis from the stop ST0 to the vertex of the object-side surface of the subsequent lens (the vertex refers to the intersection point of the lens surface and the optical axis), and we default that the direction from the object-side surface to the image-side surface of the last lens of the first lens L1 is the positive direction of the optical axis, when the value is negative, it indicates that the stop ST0 is disposed on the right side of the vertex of the object-side surface of the lens in fig. 1, and when the thickness of the stop STO is positive, the stop is on the left side of the vertex of the object-.

TABLE 1

The aspherical surface shape in the lens is defined by the following formula:

wherein x is the rise of the distance from the aspheric surface vertex to the aspheric surface vertex when the aspheric surface is at the position with the height of h along the optical axis direction; c is the paraxial curvature of the aspheric surface, c being 1/R (i.e., paraxial curvature c is the inverse of radius of curvature R in table 1); k is a conic coefficient; ai is the ith order coefficient of the aspheric surface. Table 2 below gives the high-order term coefficients a4, a6, A8, a10, a12, a14, a16, a18, and a20 that can be used for the aspherical surfaces S1 to S16 of the lens in example 1.

TABLE 2

The distance TTL on the optical axis from the object-side surface S1 of the first lens L1 to the image forming surface S19 of the optical system 100 is 4.52mm, and the image height ImgH corresponding to half the maximum field angle of the optical system 100 is 1.9 mm. As can be seen from the data in tables 1 and 2, the optical system 100 in example 1 satisfies:

f₁₂/f₃₄₅₆₇₈-1.31, wherein f₁₂Denotes a combined focal length, f, of the first lens L1 and the second lens L2₃₄₅₆₇₈Represents a combined focal length of the third lens L3 to the eighth lens L8;

TTL/ImgH＝2.379；

TTL/f is 4.04, where f denotes the effective focal length of the optical system 100;

f/RS16 is 1.36, where RS16 denotes a radius of curvature of the image-side surface S16 of the eighth lens L8 at the optical axis;

FNO 2.28, where FNO denotes the f-number of the optical system 100;

f/f3 is 0.85, where f3 denotes an effective focal length of the third lens L3;

(RS5+ RS6)/(RS5-RS6) ═ 0.37, where RS5 denotes a radius of curvature of the object-side surface S5 of the third lens L3 at the optical axis, and RS6 denotes a radius of curvature of the image-side surface S6 of the third lens L3 at the optical axis;

tan (HFOV) ═ 6.76, where HFOV represents half of the maximum field angle of the optical system 100.

Fig. 2 shows a longitudinal spherical aberration graph, an astigmatism graph, and a distortion graph of the optical system 100 of example 1, respectively. Wherein the longitudinal spherical aberration plots show the convergent focus shifts of light rays having wavelengths of 470nm, 510nm, 555nm, 610nm, and 650nm after passing through the optical system 100; the astigmatism graph shows meridional field curvature and sagittal field curvature of a light ray with a wavelength of 555nm after passing through the optical system 100; the distortion plot shows the distortion of light with a wavelength of 555nm at different image heights after passing through the optical system 100. As can be seen from fig. 2, the optical system 100 according to embodiment 1 can achieve good image quality.

Example 2

The optical system 100 of embodiment 2 of the present application is described below with reference to fig. 3 to 4. In this embodiment, a description of parts similar to those of embodiment 1 will be omitted for the sake of brevity. Fig. 3 shows a schematic structural diagram of the optical system 100 according to embodiment 2 of the present application.

As shown in fig. 3, the optical system 100 includes, in order from an object side to an image side along an optical axis, a first lens element L1, a second lens element L2, a third lens element L3, a fourth lens element L4, a fifth lens element L5, a sixth lens element L6, a seventh lens element L7, an eighth lens element L8, and an image plane S19.

The first lens element L1 with negative refractive power has an object-side surface S1 and an image-side surface S2 that are aspheric, wherein the object-side surface S1 is concave along an optical axis and convex along a circumference, and the image-side surface S2 is convex along the optical axis and concave along the circumference.

The fifth lens element L5 with positive refractive power has an object-side surface S9 and an image-side surface S10 that are aspheric, wherein the object-side surface S9 is convex along an optical axis and concave along a circumference, and the image-side surface S10 is concave along the optical axis and concave along the circumference.

The first lens element L1 to the eighth lens element L8 are all made of plastic. A stop STO is further disposed between the second lens L2 and the third lens L3 to limit the size of an incident light beam, and further improve the imaging quality of the optical system 100. The optical system 100 further includes a filter 110 disposed on the image side of the eighth lens L8 and having an object-side surface S17 and an image-side surface S18. Light from the object OBJ sequentially passes through the respective surfaces S1 to S18 and is finally imaged on the imaging plane S19. Specifically, the filter 110 is an infrared cut filter, and is made of glass.

Table 3 shows the surface type, radius of curvature, thickness, material, refractive index, abbe number (i.e., abbe number), and effective focal length of each lens of the optical system 100 of example 2, where the reference wavelength of refractive index and abbe number is 587.56nm, the reference wavelength of effective focal length is 555nm, and the unit of the radius of curvature, thickness, and effective focal length of each lens is millimeters (mm); table 4 shows high-order term coefficients that can be used for the lens aspherical surfaces S1 to S16 in embodiment 2, wherein the aspherical surface type can be defined by formula (1) given in embodiment 1.

TABLE 3

TABLE 4

Fig. 4 shows a longitudinal spherical aberration graph, an astigmatism graph, and a distortion graph of the optical system 100 of example 2, respectively. Wherein the longitudinal spherical aberration plots show the convergent focus shifts of light rays having wavelengths of 470nm, 510nm, 555nm, 610nm, and 650nm after passing through the optical system 100; the astigmatism graph shows meridional field curvature and sagittal field curvature of a light ray with a wavelength of 555nm after passing through the optical system 100; the distortion plot shows the distortion of light with a wavelength of 555nm at different image heights after passing through the optical system 100. As can be seen from fig. 4, the optical system 100 according to embodiment 2 can achieve good imaging quality.

Example 3

The optical system 100 of embodiment 3 of the present application is described below with reference to fig. 5 to 6. In this embodiment, a description of parts similar to those of embodiment 1 will be omitted for the sake of brevity. Fig. 5 shows a schematic structural diagram of an optical system 100 according to embodiment 3 of the present application.

As shown in fig. 5, the optical system 100 includes, in order from an object side to an image side along an optical axis, a first lens element L1, a second lens element L2, a third lens element L3, a fourth lens element L4, a fifth lens element L5, a sixth lens element L6, a seventh lens element L7, an eighth lens element L8, and an image plane S19.

The second lens element L2 with negative refractive power has an object-side surface S3 and an image-side surface S4 that are aspheric, wherein the object-side surface S3 is convex along an optical axis and concave along a circumference, and the image-side surface S4 is concave along the optical axis and convex along the circumference.

The fourth lens element L4 with negative refractive power has an object-side surface S7 and an image-side surface S8 that are aspheric, wherein the object-side surface S7 is convex along the optical axis and concave along the circumference, and the image-side surface S8 is concave along the optical axis and concave along the circumference.

The sixth lens element L6 with positive refractive power has an object-side surface S11 and an image-side surface S12 that are aspheric, wherein the object-side surface S11 is convex along the optical axis and concave along the circumference, and the image-side surface S12 is concave along the optical axis and concave along the circumference.

The seventh lens element L7 with positive refractive power has an object-side surface S13 and an image-side surface S14 that are aspheric, wherein the object-side surface S13 is convex along the optical axis and convex along the circumference, and the image-side surface S14 is convex along the optical axis and concave along the circumference.

The eighth lens element L8 with negative refractive power has an object-side surface S15 and an image-side surface S16 that are aspheric, wherein the object-side surface S15 is convex along the optical axis and convex along the circumference, and the image-side surface S16 is concave along the optical axis and convex along the circumference.

Table 5 shows the surface type, radius of curvature, thickness, material, refractive index, abbe number (i.e., abbe number), and effective focal length of each lens of the optical system 100 of example 3, where the reference wavelength of refractive index and abbe number is 587.56nm, the reference wavelength of effective focal length is 555nm, and the unit of radius of curvature, thickness, and effective focal length of each lens is millimeters (mm); table 6 shows high-order term coefficients that can be used for the lens aspherical surfaces S1 to S16 in embodiment 3, wherein the aspherical surface type can be defined by formula (1) given in embodiment 1.

TABLE 5

TABLE 6

Fig. 6 shows a longitudinal spherical aberration graph, an astigmatism graph, and a distortion graph of the optical system 100 of example 3, respectively. Wherein the longitudinal spherical aberration plots show the convergent focus shifts of light rays having wavelengths of 470nm, 510nm, 555nm, 610nm, and 650nm after passing through the optical system 100; the astigmatism graph shows meridional field curvature and sagittal field curvature of a light ray with a wavelength of 555nm after passing through the optical system 100; the distortion plot shows the distortion of light with a wavelength of 555nm at different image heights after passing through the optical system 100. As can be seen from fig. 6, the optical system 100 according to embodiment 3 can achieve good imaging quality.

Example 4

The optical system 100 of embodiment 4 of the present application is described below with reference to fig. 7 to 8. In this embodiment, a description of parts similar to those of embodiment 1 will be omitted for the sake of brevity. Fig. 7 shows a schematic structural diagram of an optical system 100 according to embodiment 4 of the present application.

As shown in fig. 7, the optical system 100 includes, in order from an object side to an image side along an optical axis, a first lens element L1, a second lens element L2, a third lens element L3, a fourth lens element L4, a fifth lens element L5, a sixth lens element L6, a seventh lens element L7, an eighth lens element L8, and an image plane S19.

The first lens element L1 with positive refractive power has an object-side surface S1 and an image-side surface S2 that are aspheric, wherein the object-side surface S1 is concave along an optical axis and convex along a circumference, and the image-side surface S2 is convex along the optical axis and convex along the circumference.

The second lens element L2 with negative refractive power has an object-side surface S3 and an image-side surface S4 that are aspheric, wherein the object-side surface S3 is concave along the optical axis and concave along the circumference, and the image-side surface S4 is concave along the optical axis and convex along the circumference.

The fifth lens element L5 with positive refractive power has an object-side surface S9 and an image-side surface S10 that are aspheric, wherein the object-side surface S9 is convex along the optical axis and convex along the circumference, and the image-side surface S10 is concave along the optical axis and concave along the circumference.

Table 7 shows the surface type, radius of curvature, thickness, material, refractive index, abbe number (i.e., abbe number), and effective focal length of each lens of the optical system 100 of example 4, where the reference wavelength of refractive index and abbe number is 587.56nm, the reference wavelength of effective focal length is 555nm, and the unit of radius of curvature, thickness, and effective focal length of each lens is millimeters (mm); table 8 shows high-order term coefficients that can be used for the lens aspherical surfaces S1 to S16 in example 4, wherein the aspherical surface type can be defined by formula (1) given in example 1.

TABLE 7

TABLE 8

Fig. 8 shows a longitudinal spherical aberration graph, an astigmatism graph, and a distortion graph of the optical system 100 of example 4, respectively. Wherein the longitudinal spherical aberration plots show the convergent focus shifts of light rays having wavelengths of 470nm, 510nm, 555nm, 610nm, and 650nm after passing through the optical system 100; the astigmatism graph shows meridional field curvature and sagittal field curvature of a light ray with a wavelength of 555nm after passing through the optical system 100; the distortion plot shows the distortion of light with a wavelength of 555nm at different image heights after passing through the optical system 100. As can be seen from fig. 8, the optical system 100 according to embodiment 4 can achieve good imaging quality.

Example 5

An optical system 100 of embodiment 5 of the present application is described below with reference to fig. 9 to 10. In this embodiment, a description of parts similar to those of embodiment 1 will be omitted for the sake of brevity. Fig. 9 shows a schematic structural diagram of an optical system 100 according to embodiment 5 of the present application.

As shown in fig. 9, the optical system 100 includes, in order from an object side to an image side along an optical axis, a first lens element L1, a second lens element L2, a third lens element L3, a fourth lens element L4, a fifth lens element L5, a sixth lens element L6, a seventh lens element L7, an eighth lens element L8, and an image plane S19.

The first lens element L1 with negative refractive power has an object-side surface S1 and an image-side surface S2 that are aspheric, wherein the object-side surface S1 is concave along the optical axis and convex along the circumference, and the image-side surface S2 is concave along the optical axis and concave along the circumference.

The eighth lens element L8 with negative refractive power has an object-side surface S15 and an image-side surface S16 that are aspheric, wherein the object-side surface S15 is concave along the optical axis and concave along the circumference, and the image-side surface S16 is concave along the optical axis and convex along the circumference.

Table 9 shows the surface type, radius of curvature, thickness, material, refractive index, abbe number (i.e., abbe number), and effective focal length of each lens of the optical system 100 of example 5, where the reference wavelength of refractive index and abbe number is 587.56nm, the reference wavelength of effective focal length is 555nm, and the unit of radius of curvature, thickness, and effective focal length of each lens is millimeters (mm); table 10 shows high-order term coefficients that can be used for the lens aspherical surfaces S1 to S16 in example 5, wherein the aspherical surface type can be defined by formula (1) given in example 1.

TABLE 9

Watch 10

Fig. 10 shows a longitudinal spherical aberration graph, an astigmatism graph, and a distortion graph of the optical system 100 of example 5, respectively. Wherein the longitudinal spherical aberration plots show the convergent focus shifts of light rays having wavelengths of 470nm, 510nm, 555nm, 610nm, and 650nm after passing through the optical system 100; the astigmatism graph shows meridional field curvature and sagittal field curvature of a light ray with a wavelength of 555nm after passing through the optical system 100; the distortion plot shows the distortion of light with a wavelength of 555nm at different image heights after passing through the optical system 100. As can be seen from fig. 10, the optical system 100 according to embodiment 5 can achieve good image quality.

Example 6

An optical system 100 of embodiment 6 of the present application is described below with reference to fig. 11 to 12. In this embodiment, a description of parts similar to those of embodiment 1 will be omitted for the sake of brevity. Fig. 11 shows a schematic structural diagram of an optical system 100 according to embodiment 6 of the present application.

As shown in fig. 11, the optical system 100 includes, in order from an object side to an image side along an optical axis, a first lens element L1, a second lens element L2, a third lens element L3, a fourth lens element L4, a fifth lens element L5, a sixth lens element L6, a seventh lens element L7, an eighth lens element L8, and an image plane S19.

The fifth lens element L5 with positive refractive power has an object-side surface S9 and an image-side surface S10 that are aspheric, wherein the object-side surface S9 is convex along the optical axis and convex along the circumference, and the image-side surface S10 is convex along the optical axis and concave along the circumference.

The sixth lens element L6 with negative refractive power has an object-side surface S11 and an image-side surface S12 that are aspheric, wherein the object-side surface S11 is concave along the optical axis and concave along the circumference, and the image-side surface S12 is concave along the optical axis and convex along the circumference.

The eighth lens element L8 with negative refractive power has an object-side surface S15 and an image-side surface S16 that are aspheric, wherein the object-side surface S15 is convex along the optical axis and concave along the circumference, and the image-side surface S16 is concave along the optical axis and convex along the circumference.

Table 11 shows the surface type, radius of curvature, thickness, material, refractive index, abbe number (i.e., abbe number), and effective focal length of each lens of the optical system 100 of example 6, where the reference wavelength of refractive index and abbe number is 587.56nm, the reference wavelength of effective focal length is 555nm, and the unit of radius of curvature, thickness, and effective focal length of each lens is millimeters (mm); table 12 shows high-order term coefficients that can be used for the lens aspherical surfaces S1 to S16 in embodiment 6, wherein the aspherical surface type can be defined by formula (1) given in embodiment 1.

TABLE 11

TABLE 12

Fig. 12 shows a longitudinal spherical aberration graph, an astigmatism graph, and a distortion graph of the optical system 100 of example 6, respectively. Wherein the longitudinal spherical aberration plots show the convergent focus shifts of light rays having wavelengths of 470nm, 510nm, 555nm, 610nm, and 650nm after passing through the optical system 100; the astigmatism graph shows meridional field curvature and sagittal field curvature of a light ray with a wavelength of 555nm after passing through the optical system 100; the distortion plot shows the distortion of light with a wavelength of 555nm at different image heights after passing through the optical system 100. As can be seen from fig. 12, the optical system 100 according to embodiment 6 can achieve good imaging quality.

Example 7

An optical system 100 of embodiment 7 of the present application is described below with reference to fig. 13 to 14. In this embodiment, a description of parts similar to those of embodiment 1 will be omitted for the sake of brevity. Fig. 13 is a schematic structural view showing an optical system 100 according to embodiment 7 of the present application.

As shown in fig. 13, the optical system 100 includes, in order from an object side to an image side along an optical axis, a first lens element L1, a second lens element L2, a third lens element L3, a fourth lens element L4, a fifth lens element L5, a sixth lens element L6, a seventh lens element L7, an eighth lens element L8, and an image plane S19.

The sixth lens element L6 with positive refractive power has an object-side surface S11 and an image-side surface S12 that are aspheric, wherein the object-side surface S11 is convex along an optical axis and concave along a circumference, and the image-side surface S12 is convex along the optical axis and convex along the circumference.

The seventh lens element L7 with positive refractive power has an object-side surface S13 and an image-side surface S14 that are aspheric, wherein the object-side surface S13 is concave along an optical axis and convex along a circumference, and the image-side surface S14 is convex along the optical axis and convex along the circumference.

Table 13 shows the surface type, radius of curvature, thickness, material, refractive index, abbe number (i.e., abbe number), and effective focal length of each lens of the optical system 100 of example 7, wherein the reference wavelength of refractive index and abbe number is 587.56nm, the reference wavelength of effective focal length is 555nm, and the unit of radius of curvature, thickness, and effective focal length of each lens is millimeters (mm); table 14 shows high-order term coefficients that can be used for the lens aspherical surfaces S1 to S16 in example 7, wherein the aspherical surface type can be defined by formula (1) given in example 1.

Watch 13

TABLE 14

Fig. 14 shows a longitudinal spherical aberration graph, an astigmatism graph, and a distortion graph of the optical system 100 of example 7, respectively. Wherein the longitudinal spherical aberration plots show the convergent focus shifts of light rays having wavelengths of 470nm, 510nm, 555nm, 610nm, and 650nm after passing through the optical system 100; the astigmatism graph shows meridional field curvature and sagittal field curvature of a light ray with a wavelength of 555nm after passing through the optical system 100; the distortion plot shows the distortion of light with a wavelength of 555nm at different image heights after passing through the optical system 100. As can be seen from fig. 14, the optical system 100 according to embodiment 7 can achieve good image quality.

Example 8

An optical system 100 of embodiment 8 of the present application is described below with reference to fig. 15 to 16. In this embodiment, a description of parts similar to those of embodiment 1 will be omitted for the sake of brevity. Fig. 15 shows a schematic structural diagram of an optical system 100 according to embodiment 8 of the present application.

As shown in fig. 15, the optical system 100 includes, in order from an object side to an image side along an optical axis, a first lens element L1, a second lens element L2, a third lens element L3, a fourth lens element L4, a fifth lens element L5, a sixth lens element L6, a seventh lens element L7, an eighth lens element L8, and an image plane S19.

The sixth lens element L6 with positive refractive power has an object-side surface S11 and an image-side surface S12 that are aspheric, wherein the object-side surface S11 is convex along an optical axis and concave along a circumference, and the image-side surface S12 is convex along the optical axis and concave along the circumference.

The seventh lens element L7 with negative refractive power has an object-side surface S13 and an image-side surface S14 that are aspheric, wherein the object-side surface S13 is convex along the optical axis and convex along the circumference, and the image-side surface S14 is concave along the optical axis and concave along the circumference.

Table 15 shows the surface type, radius of curvature, thickness, material, refractive index, abbe number (i.e., abbe number), and effective focal length of each lens of the optical system 100 of example 8, where the reference wavelength for refractive index and abbe number is 587.56nm, the reference wavelength for effective focal length is 555nm, and the unit of the radius of curvature, thickness, and effective focal length of each lens is millimeters (mm); table 16 shows high-order term coefficients that can be used for the lens aspherical surfaces S1 to S16 in example 8, wherein the aspherical surface type can be defined by formula (1) given in example 1.

Watch 15

TABLE 16

Fig. 16 shows a longitudinal spherical aberration graph, an astigmatism graph, and a distortion graph of the optical system 100 of example 8, respectively. Wherein the longitudinal spherical aberration plots show the convergent focus shifts of light rays having wavelengths of 470nm, 510nm, 555nm, 610nm, and 650nm after passing through the optical system 100; the astigmatism graph shows meridional field curvature and sagittal field curvature of a light ray with a wavelength of 555nm after passing through the optical system 100; the distortion plot shows the distortion of light with a wavelength of 555nm at different image heights after passing through the optical system 100. As can be seen from fig. 16, the optical system 100 according to embodiment 8 can achieve good image quality.

Example 9

An optical system 100 of embodiment 9 of the present application is described below with reference to fig. 17 to 18. In this embodiment, a description of parts similar to those of embodiment 1 will be omitted for the sake of brevity. Fig. 17 shows a schematic structural diagram of an optical system 100 according to embodiment 9 of the present application.

As shown in fig. 17, the optical system 100 includes, in order from an object side to an image side along an optical axis, a first lens element L1, a second lens element L2, a third lens element L3, a fourth lens element L4, a fifth lens element L5, a sixth lens element L6, a seventh lens element L7, an eighth lens element L8, and an image plane S19.

The fourth lens element L4 with negative refractive power has an object-side surface S7 and an image-side surface S8 that are aspheric, wherein the object-side surface S7 is concave along the optical axis and concave along the circumference, and the image-side surface S8 is concave along the optical axis and concave along the circumference.

The fifth lens element L5 with negative refractive power has an object-side surface S9 and an image-side surface S10 that are aspheric, wherein the object-side surface S9 is concave along the optical axis and concave along the circumference, and the image-side surface S10 is convex along the optical axis and concave along the circumference.

The seventh lens element L7 with positive refractive power has an object-side surface S13 and an image-side surface S14 that are aspheric, wherein the object-side surface S13 is convex along the optical axis and convex along the circumference, and the image-side surface S14 is concave along the optical axis and concave along the circumference.

Table 17 shows the surface type, radius of curvature, thickness, material, refractive index, abbe number (i.e., abbe number), and effective focal length of each lens of the optical system 100 of example 9, where the reference wavelength for refractive index and abbe number is 587.56nm, the reference wavelength for effective focal length is 555nm, and the unit of radius of curvature, thickness, and effective focal length of each lens is millimeters (mm); table 18 shows high-order term coefficients that can be used for the lens aspherical surfaces S1 to S16 in example 9, wherein the aspherical surface type can be defined by formula (1) given in example 1.

TABLE 17

Watch 18

Fig. 18 shows a longitudinal spherical aberration graph, an astigmatism graph, and a distortion graph of the optical system 100 of example 9, respectively. Wherein the longitudinal spherical aberration plots show the convergent focus shifts of light rays having wavelengths of 470nm, 510nm, 555nm, 610nm, and 650nm after passing through the optical system 100; the astigmatism graph shows meridional field curvature and sagittal field curvature of a light ray with a wavelength of 555nm after passing through the optical system 100; the distortion plot shows the distortion of light with a wavelength of 555nm at different image heights after passing through the optical system 100. As can be seen from fig. 18, the optical system 100 according to embodiment 9 can achieve good image quality.

Table 19 shows the numerical values of the correlation equations according to the present invention in the above embodiments.

Watch 19

As shown in fig. 19, the present application further provides an image capturing module 200, which includes the optical system 100 (shown in fig. 1) as described above; and a photosensitive element 210, the photosensitive element 210 being disposed on the image side of the optical system 100, a photosensitive surface of the photosensitive element 210 coinciding with the image forming surface S19. Specifically, the photosensitive element 210 may be a Complementary Metal Oxide Semiconductor (CMOS) image sensor or a Charge-coupled Device (CCD) image sensor, and the imaging surface S19 may be a plane or a curved surface with any curvature, especially a curved surface with a concave surface facing the object side, depending on the photosensitive element 210.

In other embodiments, the image capturing module 200 further includes a lens barrel (not shown) for carrying the optical system 100 and a corresponding supporting device (not shown).

In addition, the image capturing module 200 further includes a driving device (not shown) and an image stabilizing module (not shown). The driving device may have an Auto-Focus (Auto-Focus) function, and the driving method may use a driving system such as a Voice Coil Motor (VCM), a Micro Electro-Mechanical Systems (MEMS), a Piezoelectric system (piezo electric), and a Memory metal (Shape Memory Alloy). The driving device can make the optical system 100 obtain a better imaging position, so that the shot object can be shot to obtain a clear image under the state of different object distances; the image stabilization module may be an accelerometer, a gyroscope, or a Hall Effect Sensor. The driving device and the Image stabilizing module together serve as an Optical anti-shake device (OIS), and compensate a blurred Image generated by shaking at the moment of shooting by adjusting the displacement of the Optical axis of the Optical system 100, or provide an Electronic anti-shake function (EIS) by using an Image compensation technology in Image software, so as to further improve the imaging quality of shooting of dynamic and low-illumination scenes.

The image capturing module 200 can capture an image with high pixels and wide viewing angle by using the optical system 100, and the image capturing module 200 has the structural characteristics of miniaturization and light weight. The image capturing module 200 can be applied to the fields of mobile phones, automobiles, monitoring, medical treatment and the like. The camera can be used as a mobile phone camera, a vehicle-mounted camera, a monitoring camera or an endoscope and the like, and has a wide market application range.

As shown in fig. 20, the present application further provides an electronic device 300, which includes a housing 310 and the image capturing module 200 as described above, wherein the image capturing module 200 is mounted on the housing 310. Specifically, the image capturing module 200 is disposed in the housing 310 and exposed from the housing 310 to acquire an image, the housing 310 can provide protection for the image capturing module 200, such as dust prevention, water prevention, falling prevention, and the like, and the housing 310 is provided with a hole corresponding to the image capturing module 200, so that light rays penetrate into or out of the housing through the hole.

The electronic device 300 is light and can capture images with wide viewing angle and high pixels by using the image capturing module 200. In other embodiments, the electronic device 300 is further provided with a corresponding processing system, and the electronic device 300 can transmit the image to the corresponding processing system in time after the image of the object is captured, so that the system can make accurate analysis and judgment.

In other embodiments, the use of "electronic device" may also include, but is not limited to, devices configured to receive or transmit communication signals via a wireline connection and/or via a wireless interface. Electronic devices arranged to communicate over a wireless interface may be referred to as "wireless communication terminals", "wireless terminals", or "mobile terminals". Examples of mobile terminals include, but are not limited to, satellite or cellular telephones; personal Communication System (PCS) terminals that may combine a cellular radiotelephone with data processing, facsimile and data communication capabilities; personal Digital Assistants (PDAs) that may include radiotelephones, pagers, internet/intranet access, Web browsers, notepads, calendars, and/or Global Positioning System (GPS) receivers; and conventional laptop and/or palmtop receivers or other electronic devices that include a radiotelephone transceiver. In addition, the "electronic device" may further include a three-dimensional image capturing device, a digital camera, a tablet computer, a smart television, a network monitoring device, a car recorder, a car backing developing device, a multi-lens device, an identification system, a motion sensing game machine, a wearable device, and the like. The electronic device is only an exemplary embodiment of the present invention, and the application scope of the image capturing module of the present invention is not limited.

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

a fifth lens element with refractive power;

a sixth lens element with refractive power;

the optical system satisfies the following relation:

-1.8＜f₁₂/f₃₄₅₆₇₈＜-0.5；

wherein f is₁₂Denotes a combined focal length of the first lens and the second lens, f₃₄₅₆₇₈Representing the third to eighth lensesThe focal lengths are combined.

2. The optical system according to claim 1, wherein each of the object-side surface and the image-side surface of the first lens to the eighth lens is aspherical.

3. The optical system according to claim 1, wherein the optical system satisfies the following relation:

TTL/ImgH＜2.8；

wherein, TTL represents a distance on an optical axis from an object-side surface of the first lens element to an image plane of the optical system, and ImgH represents an image height corresponding to half of a maximum field angle of the optical system.

4. The optical system according to claim 1, wherein the optical system satisfies the following relation:

TTL/f＜4.5；

wherein, TTL represents a distance on an optical axis from an object-side surface of the first lens element to an image plane of the optical system, and f represents an effective focal length of the optical system.

5. The optical system according to claim 1, wherein the optical system satisfies the following relation:

0.3＜f/RS16＜2；

where f denotes an effective focal length of the optical system, and RS16 denotes a radius of curvature of an image-side surface of the eighth lens at an optical axis.

6. The optical system according to claim 1, wherein the optical system satisfies the following relation:

FNO＜2.6；

wherein FNO denotes an f-number of the optical system.

7. The optical system according to claim 1, wherein the optical system satisfies the following relation:

0.4＜f/f3＜1.2；

where f denotes an effective focal length of the optical system, and f3 denotes an effective focal length of the third lens.

8. The optical system according to claim 1, wherein the optical system satisfies the following relation:

0＜(RS5+RS6)/(RS5-RS6)＜1；

wherein RS5 denotes a radius of curvature of an object-side surface of the third lens at an optical axis, and RS6 denotes a radius of curvature of an image-side surface of the third lens at the optical axis.

9. The optical system according to claim 1, wherein the optical system satisfies the following relation:

tan(HFOV)＞2；

wherein the HFOV represents a half of a maximum angle of view of the optical system.

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

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