CN111258034A

CN111258034A - Lens system, image capturing module, electronic device and driving device

Info

Publication number: CN111258034A
Application number: CN202010230222.8A
Authority: CN
Inventors: 蔡雄宇; 兰宾利; 周芮; 赵迪
Original assignee: Tianjin OFilm Opto Electronics Co Ltd
Current assignee: Tianjin OFilm Opto Electronics Co Ltd
Priority date: 2020-03-27
Filing date: 2020-03-27
Publication date: 2020-06-09

Abstract

The application relates to a lens system, an image capturing module, an electronic device and a driving device. The lens system sequentially comprises a first lens with negative refractive power from an object side to an image side along an optical axis, and the image side surface of the first lens is a concave surface; a second lens element with positive refractive power; a third lens element with negative refractive power having a concave object-side surface and a concave image-side surface; a fourth lens element with positive refractive power having a convex image-side surface; a fifth lens element with positive refractive power; and a diaphragm provided on an object side of the lens system or between the first lens and the fifth lens. When the lens system meets the specific relation, the wide-angle-of-view lens system has the characteristics of wide visual angle, large depth of field range, high resolution capability and miniaturization.

Description

Lens system, image capturing module, electronic device and driving device

Technical Field

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

Background

In recent years, with the development of vehicle-mounted technology, the technical requirements of front-view or side-view cameras, automatic cruise instruments, automobile data recorders, and back-up cameras on vehicle-mounted cameras have become higher and higher. The forward-looking or side-looking camera device can be used as a camera system in an advanced driver assistance system to analyze video content, and Lane Departure Warning (LDW), automatic Lane Keeping Assistance (LKA), high beam/low beam control and Traffic Sign Recognition (TSR) are achieved. For example, when parking, the forward-looking or side-looking camera device is controlled to be started, so that a driver can visually see the obstacles in front of the vehicle, and the parking operation is facilitated; when the automobile passes through a special place (such as a roadblock, a parking lot and the like), the forward-looking or side-looking camera device can be automatically opened to acquire the environmental information around the automobile and feed back the environmental information to the automobile central system to make the central system make a correct instruction, so that driving accidents are avoided.

However, the conventional forward-looking or side-looking lens has low resolution and a small depth of field range, and cannot provide a clear image for a driving assistance system so that the driving assistance system can accurately judge the environmental information around the vehicle in real time to make timely early warning or avoidance, and certain driving risk exists.

Disclosure of Invention

Based on this, it is necessary to provide an improved lens system for solving the problems of low resolution and small depth of field of the conventional vehicle-mounted camera.

A lens system comprises, in order from an object side to an image side along an optical axis, a first lens element with negative refractive power having a concave image-side surface; a second lens element with positive refractive power; a third lens element with negative refractive power having a concave object-side surface and a concave image-side surface; a fourth lens element with positive refractive power having a convex image-side surface; a fifth lens element with positive refractive power; and a diaphragm disposed at an object side of the lens system or between the first lens and the fifth lens;

the lens system satisfies the following relation:

f12/f is more than 0.5 and less than 2.5; wherein f12 denotes a combined focal length of the first and second lenses, and f denotes an effective focal length of the lens system.

According to the lens system, the imaging analysis capability of the system can be enhanced, the aberration can be effectively corrected, and the image definition can be improved by selecting a proper number of lenses and reasonably distributing the refractive power and the surface shape of each lens and the effective focal length of each lens; meanwhile, the combined focal length of the first lens and the second lens is controlled to meet the relation, so that the focusing of incident light rays is facilitated, and image information collected by the lens system is effectively transmitted to an imaging surface. When f12/f exceeds the upper limit, the total refractive power provided by the first lens element and the second lens element for the system is insufficient, so that large-angle light is difficult to enter the lens system, which is not favorable for expanding the field angle range of the system; when f12/f is lower than the lower limit, the total refractive power provided by the first lens element and the second lens element is too strong, which is likely to cause too large angle of refraction of light beam and generate strong astigmatism and chromatic aberration, which is not favorable for improving the resolution of the system.

In one embodiment, an object-side surface and/or an image-side surface of at least one of the first lens to the fifth lens is aspheric.

By the mode, the flexibility of lens design can be improved, aberration can be effectively corrected, and the imaging quality of the lens system can be improved.

In one embodiment, an infrared filter is arranged between the fifth lens and an imaging surface of the lens system; or the object side surface or the image side surface of one of the first lens to the fifth lens is plated with an infrared filter film.

The infrared filter or the infrared filter coating is arranged and can be used for isolating infrared light and preventing the infrared light from being absorbed by the photosensitive element, so that the phenomenon of false color or corrugation caused by the interference of light rays in a non-working waveband is avoided, the imaging color distortion is prevented, and the imaging quality of the lens system is improved.

In one embodiment, the lens system satisfies the following relationship: -2 < f3/f < -0.5; where f3 denotes an effective focal length of the third lens.

When the relationship is satisfied, the refractive power of the third lens element can be controlled within a reasonable range, so that the decrease of the achromatic effect can be effectively inhibited, the occurrence of high-order aberration in the imaging edge area can be inhibited, and the system has higher imaging resolution performance.

In one embodiment, the lens system satisfies the following relationship: 2 < f4/CT4 < 5; where f4 denotes an effective focal length of the fourth lens, and CT4 denotes a thickness of the fourth lens on an optical axis.

When the relation is satisfied, the effective focal length of the fourth lens and the center thickness of the fourth lens can be reasonably configured, so that the tolerance sensitivity of the system is favorably reduced, the processing difficulty of the lenses is reduced, the assembly yield of the lens group is improved, and the production cost is further reduced. When f4/CT4 exceeds the upper limit, the lens system is too sensitive to the central thickness of the fourth lens, and the processing of the fourth lens is difficult to meet the required tolerance requirement, so that the assembly yield of the lens group is easily reduced, and the production cost is increased; when f4/CT4 is lower than the lower limit, the central thickness of the fourth lens is too large on the premise of meeting the optical performance of the system, and the density of the glass lenses is high, so that the weight of the lens system is increased, which is not favorable for meeting the design requirement of light weight of the system.

In one embodiment, the lens system satisfies the following relationship: f5/f is more than 1 and less than 4; where f5 denotes an effective focal length of the fifth lens.

When the relation is satisfied, enough refractive power can be configured at the tail end of the lens system, so that the angle of the chief ray incident to the imaging surface of the lens system is favorably reduced, the photosensitive performance of the photosensitive element is improved, and the resolution is improved; meanwhile, the aberration generated by the light rays refracted by the lens at the front part of the system can be corrected, and the imaging quality is ensured.

In one embodiment, the lens system satisfies the following relationship: -3.5 < f1/RS2 < 0; where f1 denotes an effective focal length of the first lens, and RS2 denotes a radius of curvature of an image side surface of the first lens at an optical axis.

When the relation is met, the first lens can be ensured to provide negative refractive power for the system, so that light rays can be fully diffused to the object side surface of the second lens, and the imaging integrity is ensured; it is also advantageous to control the degree of curvature of the first lens to correct aberrations and further reduce the ratio of occurrence of ghost images.

In one embodiment, the lens system satisfies the following relationship: 0 < (D12+ D23)/f < 3; wherein D12 represents a distance on the optical axis from the image-side surface of the first lens to the object-side surface of the second lens, and D23 represents a distance on the optical axis from the image-side surface of the second lens to the object-side surface of the third lens.

When the relation is met, the air space between the first lens and the second lens and the air space between the second lens and the third lens can be reasonably configured, so that the overlong focal length is avoided, the compact arrangement of a system structure is facilitated, and the characteristic of miniaturization is met; meanwhile, the imaging quality of the system is improved.

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

5 < | f1/CT1-f2/CT2| < 12; wherein f1 denotes an effective focal length of the first lens, f2 denotes an effective focal length of the second lens, CT1 denotes a thickness of the first lens on an optical axis, and CT2 denotes a thickness of the second lens on the optical axis.

When the relation is satisfied, the first lens provides negative refractive power for the system, and the second lens provides positive refractive power for the system, so that the thickness of the lens is controlled by matching the positive lens and the negative lens, and the lens system has the characteristics of low sensitivity and miniaturization; in addition, the object-side surface and the image-side surface of the second lens can be set to be aspheric surfaces so as to correct aberration and improve the resolving power of the system.

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

18 < | RS5-RS6|/CT3 < 28; wherein RS5 denotes a radius of curvature of an object-side surface of the third lens at an optical axis, RS6 denotes a radius of curvature of an image-side surface of the third lens at the optical axis, and CT3 denotes a thickness of the third lens on the optical axis.

When the relation is met, the curvature radius of the object side surface and the curvature radius of the image side surface of the third lens can be reasonably configured, the larger the curvature radius is, the more the surface of the lens tends to be a plane, and when the curvature radius is infinite, the object side surface or the image side surface of the third lens is a plane, so that the processing difficulty of the lens can be reduced while the aberration is corrected, the assembly sensitivity of the lens is further reduced, the production yield is improved, and the production cost is reduced; in addition, the central thickness of the third lens is controlled within a reasonable range, so that the high pixel imaging quality of the system is guaranteed, the system structure is more compact, and the requirement for miniaturization is met.

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

0 < (CT3+ CT4)/CT5 < 3; CT3 denotes a thickness of the third lens on an optical axis, CT4 denotes a thickness of the fourth lens on an optical axis, and CT5 denotes a thickness of the fifth lens on an optical axis.

When the relation is met, the central thicknesses of the third lens, the fourth lens and the fifth lens can be reasonably configured, so that the sensitivity of the rear group lens of the system is favorably reduced, the production yield is improved, and the miniaturization of the system is ensured.

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

50deg < (FOV x f)/ImgH < 70 deg; wherein FOV represents a diagonal field angle of the lens system, and ImgH represents a diagonal length of an effective pixel region on an imaging plane of the lens system.

When the above relation is satisfied, it is beneficial to achieve a balance between expanding the field angle of the system and improving the resolution capability of the system to ensure the pixel image quality.

In one embodiment, the lens system satisfies the following relationship: nd3-Nd5 is more than 0; wherein Nd3 denotes a d-optical refractive index of the third lens, and Nd5 denotes a d-optical refractive index of the fifth lens.

The refractive indexes of the light d of the third lens and the light d of the fifth lens are controlled to meet the relation, so that the off-axis chromatic aberration of the system can be corrected, the resolution of the system is improved, and the imaging definition is ensured.

In one embodiment, the lens system satisfies the following relationship: vd5-Vd3 is more than 30; wherein Vd3 denotes a d-ray abbe number of the third lens, and Vd5 denotes a d-ray abbe number of the fifth lens.

The d-ray abbe numbers of the third lens and the fifth lens are controlled to meet the relation, so that the axial chromatic aberration and the magnification chromatic aberration of the system can be corrected, and the imaging resolution can be improved; meanwhile, the method is also beneficial to reducing the sensitivity of the system, improving the production yield and reducing the production cost.

In one embodiment, the lens system satisfies the following relationship: BFL/TTL is more than 0 and less than 1; wherein BFL represents an optical back focus of the lens system, and TTL represents a distance on an optical axis from the first lens to an imaging surface of the lens system.

When the relation is satisfied, the system is favorable for obtaining larger optical back focus, thereby the system has telecentric effect, the sensitivity of the system is reduced, and simultaneously, the system is favorable for obtaining shorter total length of the system and realizing miniaturization.

The application also provides an image capturing module.

An image capturing module comprises the lens system and a photosensitive element, wherein the photosensitive element is arranged at the image side of the lens system.

The image capturing module can capture images with large depth of field, high pixels and wide visual angle by using the lens system, has the structural characteristics of miniaturization and light weight, and is convenient to adapt to devices with limited sizes such as mobile phones, flat plates and vehicle-mounted lenses.

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.

The electronic device can shoot images with wide visual angle, high pixel and large field depth range by utilizing the image capturing module, and can transmit the images to the corresponding processing system in time so that the system can make accurate analysis and judgment.

The application also provides a driving device.

A driving device comprises a vehicle body and the image capturing module, wherein the image capturing module is arranged on the vehicle body to acquire environmental information around the vehicle body.

The driving device can timely and accurately acquire the surrounding environmental information through the image acquisition module, and can analyze the surrounding road conditions in real time according to the acquired environmental information, so that the driving safety is improved.

Drawings

Fig. 1 shows a schematic structural view of a lens 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 lens system of example 1;

FIG. 3 is a schematic structural view showing a lens 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 lens system of example 2;

FIG. 5 is a schematic structural view showing a lens 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 lens system of example 3;

FIG. 7 is a schematic structural view showing a lens system of embodiment 4 of the present application;

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

FIG. 9 is a schematic structural view showing a lens system of embodiment 5 of the present application;

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

FIG. 11 is a schematic structural view showing a lens system of embodiment 6 of the present application;

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

FIG. 13 is a schematic structural view showing a lens system of embodiment 7 of the present application;

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

FIG. 15 is a schematic structural view showing a lens system of embodiment 8 of the present application;

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

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

fig. 18 shows a longitudinal spherical aberration chart, an astigmatism chart, and a distortion chart of the lens 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 a driving device using an image capturing module according to an embodiment of the present application;

fig. 21 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.

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, the present invention provides a lens system that can achieve a wide viewing angle, a high pixel ratio, and a small size. Specifically, the lens system includes five lens elements with refractive power, namely, a first lens element, a second lens element, a third lens element, a fourth lens element and a fifth lens element. The five lens elements are arranged in sequence from an object side to an image side along an optical axis, and an imaging surface of the lens system is positioned on the image side of the fifth lens element.

The first lens has negative refractive power, so that large-angle light can enter the lens system, the light is converged to an imaging surface of the lens through refraction of other lenses in the lens system, the imaging quality is improved, the imaging side surface of the first lens is concave, aberration correction is facilitated, and the imaging quality is improved.

The second lens element with positive refractive power can correct system aberration in cooperation with the first lens element with negative refractive power, and has reduced system sensitivity and reduced size.

The third lens element with negative refractive power can effectively eliminate chromatic aberration of the system and obtain high resolution performance, and the object-side surface and the image-side surface of the third lens element are both concave surfaces, thereby facilitating correction of system aberration, reducing assembly sensitivity of the lens elements, improving production yield and reducing production cost.

The fourth lens has positive refractive power, so that the light rays refracted by the third lens can be further converged, the imaging quality is ensured, the system structure is compact, and the miniaturization is realized.

The fifth lens element has positive refractive power, and is beneficial to reducing the angle of the chief ray incident on the imaging surface of the system, improving the photosensitive performance of the photosensitive element and improving the resolution; meanwhile, the aberration generated by the light rays refracted by the lens at the front part of the system can be corrected, and the imaging quality is ensured.

The lens system is also provided with a diaphragm, and the diaphragm is arranged at the object side of the lens system or between the first lens and the fifth lens so as to better control the size of an incident beam and improve the imaging quality of the lens system. Further, the diaphragm is arranged between the second lens and the third lens. Specifically, the diaphragms include an aperture diaphragm and a field diaphragm. 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 particular, the lens system further satisfies the following relationship: f12/f is more than 0.5 and less than 2.5; where f12 denotes a combined focal length of the first lens and the second lens, and f denotes an effective focal length of the lens system. f12/f may be 0.6, 0.8, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 2 or 2.3. Under the condition of satisfying the above relational expression, the focusing of incident light is facilitated, so that the image information collected by the lens system is effectively transmitted to an imaging surface. When f12/f is greater than or equal to 2.5, the total refractive power provided by the first lens element and the second lens element for the system is insufficient, and large-angle light is difficult to enter the lens system, which is not favorable for expanding the field angle range of the system; when f12/f is less than or equal to 0.5, the total refractive power provided by the first lens element and the second lens element is too strong, which is likely to cause too large angle of refraction of light to generate strong astigmatism and chromatic aberration, which is not favorable for improving the resolution of the system.

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

According to the lens system, the refractive power and the surface shape of each lens and the effective focal length of each lens are reasonably distributed by selecting a proper number of lenses, so that the imaging analysis capability of the lens can be enhanced, the aberration can be effectively corrected, the details of a scene can be more accurately captured, and the image definition is improved; meanwhile, by reasonably configuring the combined focal length of the first lens and the second lens, chromatic aberration can be effectively eliminated, the occurrence of high-order aberration of an imaging edge area is inhibited, and the imaging resolution capability of the system is improved.

In an exemplary embodiment, an object-side surface and/or an image-side surface of at least one of the first lens to the fifth lens is aspheric. By the mode, the flexibility of lens design can be improved, aberration can be effectively corrected, and the imaging quality of the lens system can be improved. It should be noted that the surfaces of the lenses in the lens system may be any combination of spherical and aspherical surfaces, and are not necessarily both spherical or both aspherical.

In an exemplary embodiment, an infrared filter is disposed between the fifth lens and the imaging surface of the lens system; or the object side surface or the image side surface of one of the first lens to the fifth lens is coated with an infrared filter film.

Through setting up infrared filter or plating infrared filter membrane for filter incident light completely cuts off the infrared light, prevent that the infrared light from being absorbed by photosensitive element to avoid producing pseudo-color or ripple's phenomenon because of the interference of non-working wave band light, prevent the formation of image color distortion, improve lens system's formation of image quality.

In an exemplary embodiment, the lens system satisfies the following relationship: -2 < f3/f < -0.5; where f denotes an effective focal length of the lens system, and f3 denotes an effective focal length of the third lens. f3/f can be-1.5, -1.4, -1.3, -1.2, -1.1, -1, -0.9, -0.8, -0.7, -0.6 or-0.5. Under the condition of satisfying the relational expression, the refractive power of the third lens can be controlled within a reasonable range, so that the reduction of the achromatic effect can be effectively inhibited, the occurrence of high-order aberration of an imaging edge area is inhibited, and the system has higher imaging resolution performance. When f3/f is greater than or equal to-0.5, the negative refractive power of the third lens element is too strong, which tends to cause too large incident angles of light rays at the object-side surface and the image-side surface of the third lens element, thereby causing generation of high-order aberration in the image-forming edge region; and when f3/f is less than or equal to-2, the negative refractive power of the third lens is small, so that the achromatic effect is not obvious, and the definition of an image is difficult to ensure.

In an exemplary embodiment, the lens system satisfies the following relationship: 2 < f4/CT4 < 5; where f4 denotes an effective focal length of the fourth lens, and CT4 denotes a thickness of the fourth lens on the optical axis. f4/CT4 may be 2.4, 2.6, 2.8, 3, 3.2, 3.4, 3.6, 3.8, 4, 4.2, 4.4, 4.6, or 4.8. Under the condition of satisfying the above relation, the effective focal length of the fourth lens and the center thickness of the fourth lens can be reasonably configured, thereby being beneficial to reducing the tolerance sensitivity of the system, reducing the processing difficulty of the lenses, improving the assembly yield of the lens group and further reducing the production cost. When f4/CT4 is greater than or equal to 5, the lens system is too sensitive to the central thickness of the fourth lens, and the processing of the fourth lens is difficult to meet the required tolerance requirement, so that the assembly yield of the lens group is easily reduced, and the production cost is increased; when f4/CT4 is less than or equal to 2, the thickness of the center of the fourth lens is too large on the premise of satisfying the optical performance of the system, and the density of the glass lens is high, which also increases the weight of the lens system, thus being not favorable for satisfying the light weight design requirement of the system.

In an exemplary embodiment, the lens system satisfies the following relationship: f5/f is more than 1 and less than 4; where f denotes an effective focal length of the lens system, and f5 denotes an effective focal length of the fifth lens. f5/f may be 1.5, 1.8, 2.1, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, 3.1, 3.4 or 3.7. Under the condition of satisfying the relational expression, enough refractive power can be configured at the tail end of the system, so that the angle of the chief ray incident to the imaging surface of the lens system is favorably reduced, the photosensitive performance of the photosensitive element is improved, and the resolution is improved; meanwhile, the aberration generated by the light rays refracted by the lens at the front part of the system can be corrected, and the imaging quality is ensured. When f5/f is less than or equal to 1, the effective focal length of the lens is easy to be larger, which is not beneficial to the wide angle and the miniaturization of the system; when f5/f is greater than or equal to 4, the fifth lens element cannot provide sufficient positive refractive power, which is not favorable for reducing the incident angle of the chief ray on the image plane, and thus the resolution of the system is not high.

In an exemplary embodiment, the lens system satisfies the following relationship: -3.5 < f1/RS2 < 0; where f1 denotes an effective focal length of the first lens, and RS2 denotes a radius of curvature of an image-side surface of the first lens at the optical axis. f1/RS2 can be-3, -2.5, -2.4, -2.3, -2.2, -2, -1.8, -1.6, -1.4, -1.2, or-1. Under the condition of meeting the relational expression, the first lens can be ensured to provide negative refractive power for the system, so that light rays can be fully diffused to the object side surface of the second lens, and the imaging integrity is ensured; it is also advantageous to control the degree of curvature of the first lens to correct aberrations and further reduce the ratio of occurrence of ghost images. When f1/RS2 is greater than or equal to 0, the first lens element cannot provide negative refractive power, which is not favorable for the wide angle of the system and the light imaging; when f1/RS2 is less than or equal to-3.5, the image side of the first lens is easy to be over-bent, which is not favorable for correcting aberration and avoiding ghost image.

In an exemplary embodiment, the lens system satisfies the following relationship: 0 < (D12+ D23)/f < 3; where D12 denotes an axial distance between an image-side surface of the first lens and an object-side surface of the second lens, D23 denotes an axial distance between an image-side surface of the second lens and an object-side surface of the third lens, and f denotes an effective focal length of the lens system. (D12+ D23)/f may be 0.5, 0.7, 0.9, 1.1, 1.3, 1.5, 1.7, 2 or 2.5. Under the condition of meeting the relational expression, the air space between the first lens and the second lens and the air space between the second lens and the third lens can be reasonably configured, so that the overlong focal length is avoided, the compact arrangement of a system structure is facilitated, and the characteristic of miniaturization is met; meanwhile, the imaging quality of the system is improved.

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

5 < | f1/CT1-f2/CT2| < 12; where f1 denotes an effective focal length of the first lens, f2 denotes an effective focal length of the second lens, CT1 denotes a thickness of the first lens on the optical axis, and CT2 denotes a thickness of the second lens on the optical axis. I f1/CT1-f2/CT2| can be 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, or 11.5. Under the condition of satisfying the relation, the first lens provides negative refractive power for the system, and the second lens provides positive refractive power for the system, so that the thickness of the lens can be controlled by matching the positive lens and the negative lens, and the lens system has the characteristics of low sensitivity and miniaturization; in addition, the object-side surface and the image-side surface of the second lens can be set to be aspheric surfaces so as to correct aberration and improve the resolving power of the system.

In an exemplary embodiment, the lens system satisfies the following relationship: 18 < | RS5-RS6|/CT3 < 28; where RS5 denotes a radius of curvature of an object-side surface of the third lens at the optical axis, RS6 denotes a radius of curvature of an image-side surface of the third lens at the optical axis, and CT3 denotes a thickness of the third lens on the optical axis. The | RS5-RS6|/CT3 can be 18.1, 18.6, 19, 20, 21, 22, 23, 24, 25, 26, 27, or 27.5. Under the condition of meeting the relational expression, the curvature radius of the object side surface and the curvature radius of the image side surface of the third lens can be reasonably configured, the larger the curvature radius is, the more the surface of the lens tends to be a plane, and when the curvature radius is infinite, the object side surface or the image side surface of the third lens is the plane, so that the processing difficulty of the lens can be reduced while the aberration is corrected, the assembly sensitivity of the lens is further reduced, the production yield is improved, and the production cost is reduced; in addition, the central thickness of the third lens is controlled within a reasonable range, so that the high pixel imaging quality of the system is guaranteed, the system structure is more compact, and the requirement for miniaturization is met.

In an exemplary embodiment, the lens system satisfies the following relationship: 0 < (CT3+ CT4)/CT5 < 3; CT3 denotes a thickness of the third lens on the optical axis, CT4 denotes a thickness of the fourth lens on the optical axis, and CT5 denotes a thickness of the fifth lens on the optical axis. (CT3+ CT4)/CT5 may be 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.5, or 2.9. Under the condition of satisfying the relational expression, the central thicknesses of the third lens, the fourth lens and the fifth lens can be reasonably configured, so that the sensitivity of the rear group lens of the system can be reduced, the production yield can be improved, and the miniaturization of the system can be ensured.

In an exemplary embodiment, the lens system satisfies the following relationship: 50deg < (FOV x f)/ImgH < 70 deg; where FOV represents a diagonal field angle of the lens system, f represents an effective focal length of the lens system, and ImgH represents a diagonal length of an effective pixel area on an imaging plane of the lens system. (FOV x f)/ImgH may be 55deg, 56deg, 57deg, 58deg, 59deg, 60deg, 64deg or 68 deg. Under the condition of satisfying the above relation, it is beneficial to obtain the balance between expanding the field angle of the system and improving the resolution capability of the system to ensure the pixel image quality.

In an exemplary embodiment, the lens system satisfies the following relationship: nd3-Nd5 is more than 0; where Nd3 denotes the d-optical refractive index of the third lens, and Nd5 denotes the d-optical refractive index of the fifth lens. Nd3-Nd5 may be 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, or 0.5. The refractive indexes of the light d of the third lens and the light d of the fifth lens are controlled to meet the relation, so that the off-axis chromatic aberration of the system can be corrected, the resolution of the system is improved, and the imaging definition is ensured.

In an exemplary embodiment, the lens system satisfies the following relationship: vd5-Vd3 is more than 30; vd3 represents the d-ray abbe number of the third lens, and Vd5 represents the d-ray abbe number of the fifth lens. Vd5-Vd3 may be 30.5, 30.7, 40, 45, 47, 49, or 50. The d-ray abbe numbers of the third lens and the fifth lens are controlled to meet the relation, so that the axial chromatic aberration and the magnification chromatic aberration of the system can be corrected, and the imaging resolution can be improved; meanwhile, the method is also beneficial to reducing the sensitivity of the system, improving the production yield and reducing the production cost.

In an exemplary embodiment, the lens system satisfies the following relationship: BFL/TTL is more than 0 and less than 1; wherein BFL denotes an optical back focus of the lens system, and TTL denotes a distance on the optical axis from the first lens to an image plane of the lens system. The BFL/TTL can be 0.1, 0.2, 0.25, 0.28, 0.29, 0.3, 0.31, 0.32, 0.33, 0.4, 0.6, or 0.8. Under the condition of satisfying the relational expression, the method is favorable for obtaining larger optical back focus, thereby ensuring that the system has telecentric effect, reducing the sensitivity of the system, simultaneously being favorable for obtaining shorter total length of the system and realizing miniaturization.

In an exemplary embodiment, each lens in the lens system may be made of glass or plastic, the plastic lens can reduce the weight and production cost of the lens system, and the glass lens can provide the lens system with better temperature tolerance and excellent optical performance. Further, when used in an in-vehicle system, the material of each lens is preferably glass. It should be noted that the material of each lens in the lens system may be any combination of glass and plastic, and is not necessarily all glass or all plastic.

In an exemplary embodiment, the lens system further comprises a protective glass. The protective glass is arranged on the image side of the fifth lens or the image side of the infrared filter, plays a role in protecting the photosensitive element, can prevent the photosensitive element from being polluted and dusted, and further ensures the imaging quality.

The lens system of the above-described embodiments of the present application may employ a multi-piece optic, such as the five pieces described above. Through reasonable distribution of focal length, refractive power, surface type, thickness of each lens, on-axis distance between each lens and the like, the total length of the lens system is small, the weight is light, the imaging resolution is high, and the lens system also has a large aperture (FNO can be 2.3) and a large field angle, so that the application requirements of light-weight electronic equipment such as a lens, a mobile phone and a flat panel of a vehicle-mounted auxiliary system are met better. However, it will be appreciated by those skilled in the art that the number of lenses making up the lens system can be varied to achieve the various results and advantages described in this specification without departing from the claimed subject matter.

Specific examples of lens systems that can be applied to the above-described embodiments are further described below with reference to the drawings.

Example 1

A lens 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 of a lens system 100 of embodiment 1. As shown in fig. 1, the lens 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 and an image plane S13.

The first lens element L1 with negative refractive power has a planar object-side surface S1 and a spherical image-side surface S2, wherein the image-side surface S2 is concave.

The second lens element L2 with positive 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 at a paraxial region thereof and the image-side surface S4 is convex at a paraxial region thereof.

The third lens element L3 with negative refractive power has a spherical object-side surface S5 and a spherical image-side surface S6, wherein the object-side surface S5 is concave and the image-side surface S6 is concave.

The fourth lens element L4 with positive refractive power has a spherical object-side surface S7 and a spherical image-side surface S8, wherein the object-side surface S7 is convex and the image-side surface S8 is convex.

The fifth lens element L5 with positive refractive power has a spherical object-side surface S9 and a spherical image-side surface S10, wherein the object-side surface S9 is convex and the image-side surface S10 is convex.

The object-side surface S3 and the image-side surface S4 of the second lens element L2 are both aspheric, which is advantageous for correcting aberrations and solving the problem of image surface distortion, and enables the lens system 100 to have a compact size with excellent optical imaging effect even when the lens is small, thin and flat.

The first lens L1 to the fifth lens L5 are made of glass, and the lens system 100 has good temperature tolerance and excellent optical performance by using the glass lens, so as to further ensure the imaging quality.

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 lens system 100. The lens system 100 further includes a cover glass 120 disposed on the image side of the fifth lens L5 and having an object-side surface S11 and an image-side surface S12. Light from the object OBJ sequentially passes through the respective surfaces S1 to S12 and is finally imaged on the imaging plane S13.

Further, the image-side surface S10 of the fifth lens element L5 is coated with an infrared filter for filtering out infrared light from the external light incident on the lens system 100, so as to avoid the occurrence of false color or moire due to interference of light in non-working bands, and prevent the distortion of imaging colors.

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 system 100 of example 1, wherein the unit of the 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 and the optical axis), and we default that the direction from the object-side surface of the first lens L1 to the image-side surface of the last lens 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 S3 to S4 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 imaging surface S13 of the lens system 100 is 22.957mm, and the diagonal length ImgH of the effective pixel region on the imaging surface S13 of the lens system 100 is 6 mm. As can be seen from the data in tables 1 and 2, the lens system 100 in example 1 satisfies:

f12/f is 1.47, where f12 denotes a combined focal length of the first lens L1 and the second lens L2, and f denotes an effective focal length of the lens system 100;

f3/f is-0.99, where f denotes an effective focal length of the lens system 100, and f3 denotes an effective focal length of the third lens L3;

f4/CT4 ═ 3.437, where f4 denotes the effective focal length of the fourth lens L4, and CT4 denotes the thickness of the fourth lens L4 on the optical axis;

f5/f is 2.469, where f denotes an effective focal length of the lens system 100, and f5 denotes an effective focal length of the fifth lens L5;

f1/RS2 is-1.69, where f1 denotes an effective focal length of the first lens L1, and RS2 denotes a radius of curvature of the image side surface S2 of the first lens L1 at the optical axis;

(D12+ D23)/f is 1.19, where D12 represents the distance on the optical axis from the image-side surface S2 of the first lens L1 to the object-side surface S3 of the second lens L2, D23 represents the distance on the optical axis from the image-side surface S4 of the second lens L2 to the object-side surface S5 of the third lens L3, and f represents the effective focal length of the lens system 100;

i f1/CT1-f2/CT2| -8.547, wherein f1 represents the effective focal length of the first lens L1, f2 represents the effective focal length of the second lens L2, CT1 represents the thickness of the first lens L1 on the optical axis, and CT2 represents the thickness of the second lens L2 on the optical axis;

i RS5-RS6 i/CT 3 ═ 27.02, where RS5 denotes the radius of curvature of the object side surface S5 of the third lens L3 at the optical axis, RS6 denotes the radius of curvature of the image side surface S6 of the third lens L3 at the optical axis, and CT3 denotes the thickness of the third lens L3 on the optical axis;

(CT3+ CT4)/CT5 is 1.442, where CT3 denotes a thickness of the third lens L3 on the optical axis, CT4 denotes a thickness of the fourth lens L4 on the optical axis, and CT5 denotes a thickness of the fifth lens L5 on the optical axis;

(FOV x f)/ImgH 58.769deg, where FOV represents the diagonal field angle of the lens system 100, f represents the effective focal length of the lens system 100, and ImgH represents the diagonal length of the effective pixel area on the imaging plane S13 of the lens system 100;

nd3-Nd5 is 0.436, where Nd3 denotes the d-light refractive index of the third lens L3, and Nd5 denotes the d-light refractive index of the fifth lens L5;

vd5-Vd3 is 49.5, where Vd3 denotes the d-ray abbe number of the third lens L3, and Vd5 denotes the d-ray abbe number of the fifth lens L5;

BFL/TTL ═ 0.325, where BFL denotes the optical back focus of the lens system 100, and TTL denotes the distance on the optical axis from the first lens L1 to the image plane S13 of the lens system 100.

Fig. 2 shows a longitudinal spherical aberration plot, an astigmatism plot, and a distortion plot, respectively, of the lens system 100 of example 1, the lens system 100 having a reference wavelength of 546.07 nm. Wherein the longitudinal spherical aberration plots show the convergent focus shifts of light rays having wavelengths of 435.83nm, 479.99nm, 546.07nm, 587.56nm, and 656.27nm through lens system 100; the astigmatism graphs show the meridional field curvature and the sagittal field curvature of a light ray with a wavelength of 546.07nm after passing through the lens system 100; the distortion plot shows the distortion for different image heights after light with a wavelength of 546.07nm passes through the lens system 100. As can be seen from fig. 2, the lens system 100 according to embodiment 1 can achieve good imaging quality.

Example 2

The lens 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 lens system 100 of embodiment 2 of the present application.

As shown in fig. 3, the lens 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 and an image plane S13.

The first lens element L1 with negative refractive power has a spherical object-side surface S1 and a spherical image-side surface S2, wherein the object-side surface S1 is convex and the image-side surface S2 is concave.

The second lens element L2 with positive refractive power has a spherical object-side surface S3 and a spherical image-side surface S4, wherein the object-side surface S3 is convex and the image-side surface S4 is convex.

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 at a paraxial region thereof and the image-side surface S10 is concave at a paraxial region thereof.

The object-side surface S9 and the image-side surface S10 of the fifth lens L5 are both aspheric. The first lens element L1 to the fifth lens element L5 are made of glass. 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 lens system 100. The lens system 100 further includes a cover glass 120 disposed on the image side of the fifth lens L5 and having an object-side surface S11 and an image-side surface S12.

Further, the object-side surface S7 of the fourth lens element L4 is coated with an infrared filter for filtering out infrared light from the external light incident on the lens system 100, thereby avoiding the occurrence of false color or moire due to interference of light in non-working bands and preventing the distortion of imaging colors.

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 lens system 100 of example 2, wherein 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 aspheres S9-S10 in example 2, in which the aspherical surface types can be defined by formula (1) given in example 1; table 5 shows the values of relevant parameters of the lens system 100 given in example 2.

TABLE 3

TABLE 4

TABLE 5

Fig. 4 shows a longitudinal spherical aberration graph, an astigmatism graph, and a distortion graph, respectively, of the lens system 100 of example 2, the reference wavelength of the lens system 100 being 587.56 nm. Wherein the longitudinal spherical aberration plots show the convergent focus shifts of light rays having wavelengths of 435.83nm, 479.99nm, 546.07nm, 587.56nm, and 656.27nm through lens system 100; the astigmatism graphs show the meridional and sagittal curvature of field of a light ray with a wavelength of 587.56nm after passing through the lens system 100; the distortion plot shows the distortion for different image heights for light having a wavelength of 587.56nm after passing through the lens system 100. As can be seen from fig. 4, the lens system 100 according to embodiment 2 can achieve good imaging quality.

Example 3

The lens 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 the lens system 100 of embodiment 3 of the present application.

As shown in fig. 5, the lens 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 and an image plane S13.

The fifth lens element L5 with positive refractive power has an aspheric object-side surface S9 and a spherical image-side surface S10, wherein the object-side surface S9 is convex at the paraxial region and the image-side surface S10 is concave.

The object side S9 of the fifth lens L5 is aspheric. The first lens element L1 to the fifth lens element L5 are made of glass. 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 lens system 100. The lens system 100 further includes a cover glass 120 disposed on the image side of the fifth lens L5 and having an object-side surface S11 and an image-side surface S12.

Further, the image-side surface S4 of the second lens L2 is coated with an infrared filter for filtering out infrared light from the external light incident on the lens system 100, so as to avoid the occurrence of false color or moire due to interference of light in non-working bands, and prevent the distortion of imaging color.

Table 6 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 lens system 100 of example 3, wherein the unit of the radius of curvature, thickness, and effective focal length of each lens is millimeters (mm); table 7 shows high-order term coefficients that can be used for the lens aspherical surface S9 in embodiment 3, wherein the aspherical surface type can be defined by formula (1) given in embodiment 1; table 8 shows the values of relevant parameters of the lens system 100 given in example 3.

TABLE 6

TABLE 7

TABLE 8

Fig. 6 shows a longitudinal spherical aberration graph, an astigmatism graph, and a distortion graph, respectively, of the lens system 100 of example 3, the reference wavelength of the lens system 100 being 546.07 nm. Wherein the longitudinal spherical aberration plots show the convergent focus shifts of light rays having wavelengths of 435.83nm, 479.99nm, 546.07nm, 587.56nm, and 656.27nm through lens system 100; the astigmatism graphs show the meridional field curvature and the sagittal field curvature of a light ray with a wavelength of 546.07nm after passing through the lens system 100; the distortion plot shows the distortion for different image heights after light with a wavelength of 546.07nm passes through the lens system 100. As can be seen from fig. 6, the lens system 100 according to embodiment 3 can achieve good imaging quality.

Example 4

The lens 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 a lens system 100 according to embodiment 4 of the present application.

As shown in fig. 7, the lens 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 and an image plane S13.

The fifth lens element L5 with positive refractive power has an aspheric object-side surface S9 and a planar image-side surface S10, wherein the object-side surface S9 is convex at the paraxial region.

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 lens system 100 of example 4, wherein the unit of the 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 surface S9 in embodiment 4, wherein the aspherical surface type can be defined by formula (1) given in embodiment 1; table 11 shows the values of relevant parameters of the lens system 100 given in example 4.

TABLE 9

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TABLE 11

Fig. 8 shows a longitudinal spherical aberration graph, an astigmatism graph, and a distortion graph, respectively, of the lens system 100 of example 4, the reference wavelength of the lens system 100 being 546.07 nm. Wherein the longitudinal spherical aberration plots show the convergent focus shifts of light rays having wavelengths of 435.83nm, 479.99nm, 546.07nm, 587.56nm, and 656.27nm through lens system 100; the astigmatism graphs show the meridional field curvature and the sagittal field curvature of a light ray with a wavelength of 546.07nm after passing through the lens system 100; the distortion plot shows the distortion for different image heights after light with a wavelength of 546.07nm passes through the lens system 100. As can be seen from fig. 8, the lens system 100 according to embodiment 4 can achieve good imaging quality.

Example 5

A lens 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 a lens system 100 of embodiment 5 of the present application.

As shown in fig. 9, the lens 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 and an image plane S13.

Table 12 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 lens system 100 of example 5, wherein the unit of the radius of curvature, thickness, and effective focal length of each lens is millimeters (mm); table 13 shows high-order term coefficients that can be used for the lens aspherical surfaces S9 to S10 in example 5, wherein the aspherical surface type can be defined by formula (1) given in example 1; table 14 shows the values of relevant parameters of the lens system 100 given in example 5.

TABLE 12

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TABLE 14

Fig. 10 shows a longitudinal spherical aberration plot, an astigmatism plot, and a distortion plot, respectively, of the lens system 100 of example 5, the reference wavelength of the lens system 100 being 546.07 nm. Wherein the longitudinal spherical aberration plots show the convergent focus shifts of light rays having wavelengths of 435.83nm, 479.99nm, 546.07nm, 587.56nm, and 656.27nm through lens system 100; the astigmatism graphs show the meridional field curvature and the sagittal field curvature of a light ray with a wavelength of 546.07nm after passing through the lens system 100; the distortion plot shows the distortion for different image heights after light with a wavelength of 546.07nm passes through the lens system 100. As can be seen from fig. 10, the lens system 100 according to embodiment 5 can achieve good imaging quality.

Example 6

A lens 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 a lens system 100 of embodiment 6 of the present application.

As shown in fig. 11, the lens 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 and an image plane S15.

The fourth lens element L4 with positive refractive power has a planar object-side surface S7 and a spherical image-side surface S8, wherein the image-side surface S8 is convex.

The fifth lens element L5 with positive refractive power has a spherical object-side surface S9 and a planar image-side surface S10, wherein the object-side surface S9 is convex.

The object-side surface S3 and the image-side surface S4 of the second lens L2 are both aspheric. The first lens element L1 to the fifth lens element L5 are made of glass. 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 lens system 100. The lens system 100 further includes an infrared filter 110 disposed on the image side of the fifth lens L5 and having an object-side surface S11 and an image-side surface S12, and a cover glass 120 disposed on the image side of the infrared filter 110 and having an object-side surface S13 and an image-side surface S14. Light from the object OBJ sequentially passes through the respective surfaces S1 to S14 and is finally imaged on the imaging plane S15. The infrared filter 110 is used to filter out infrared light from the external light incident on the lens system 100, so as to avoid the phenomenon of false color or moire caused by the interference of light in the non-working band, and prevent the distortion of imaging color. Specifically, the infrared filter 110 is made of glass.

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 lens system 100 of example 6, wherein 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 S3 to S4 in example 6, wherein the aspherical surface types can be defined by formula (1) given in example 1; table 17 shows the values of relevant parameters of the lens system 100 given in example 6.

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TABLE 16

TABLE 17

Fig. 12 shows a longitudinal spherical aberration graph, an astigmatism graph, and a distortion graph, respectively, of the lens system 100 of example 6, the reference wavelength of the lens system 100 being 587.56 nm. Wherein the longitudinal spherical aberration plots show the convergent focus shifts of light rays having wavelengths of 435.83nm, 479.99nm, 546.07nm, 587.56nm, and 656.27nm through lens system 100; the astigmatism graphs show the meridional and sagittal curvature of field of a light ray with a wavelength of 587.56nm after passing through the lens system 100; the distortion plot shows the distortion for different image heights for light having a wavelength of 587.56nm after passing through the lens system 100. As can be seen from fig. 12, the lens system 100 according to embodiment 6 can achieve good imaging quality.

Example 7

A lens 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 a lens system 100 according to embodiment 7 of the present application.

As shown in fig. 13, the lens 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 and an image plane S15.

The second lens element L2 with positive refractive power has a planar object-side surface S3 and an aspheric image-side surface S4, wherein the image-side surface S4 is convex at the paraxial region.

The fifth lens element L5 with positive refractive power has a spherical object-side surface S9 and a spherical image-side surface S10, wherein the object-side surface S9 is convex and the image-side surface S10 is concave.

The image-side surfaces S4 of the second lens L2 are each aspheric. The first lens element L1 to the fifth lens element L5 are made of glass. 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 lens system 100. The lens system 100 further includes an infrared filter 110 disposed on the image side of the fifth lens L5 and having an object-side surface S11 and an image-side surface S12, and a cover glass 120 disposed on the image side of the infrared filter 110 and having an object-side surface S13 and an image-side surface S14. Light from the object OBJ sequentially passes through the respective surfaces S1 to S14 and is finally imaged on the imaging plane S15. The infrared filter 110 is used to filter out infrared light from the external light incident on the lens system 100, so as to avoid the phenomenon of false color or moire caused by the interference of light in the non-working band, and prevent the distortion of imaging color. Specifically, the infrared filter 110 is made of glass.

Table 18 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 lens system 100 of example 7, wherein the unit of the radius of curvature, thickness, and effective focal length of each lens is millimeters (mm); table 19 shows high-order term coefficients that can be used for the lens aspherical surface S4 in embodiment 7, wherein the aspherical surface type can be defined by formula (1) given in embodiment 1; table 20 shows the values of relevant parameters of the lens system 100 given in example 7.

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Watch 20

Fig. 14 shows a longitudinal spherical aberration graph, an astigmatism graph, and a distortion graph, respectively, of the lens system 100 of example 7, the reference wavelength of the lens system 100 being 587.56 nm. Wherein the longitudinal spherical aberration plots show the convergent focus shifts of light rays having wavelengths of 435.83nm, 479.99nm, 546.07nm, 587.56nm, and 656.27nm through lens system 100; the astigmatism graphs show the meridional and sagittal curvature of field of a light ray with a wavelength of 587.56nm after passing through the lens system 100; the distortion plot shows the distortion for different image heights for light having a wavelength of 587.56nm after passing through the lens system 100. As can be seen from fig. 14, the lens system 100 according to embodiment 7 can achieve good imaging quality.

Example 8

A lens 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 view of a lens system 100 according to embodiment 8 of the present application.

As shown in fig. 15, the lens 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 and an image plane S13.

The first lens element L1 to the fifth lens element L5 are made of glass. 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 lens system 100. The lens system 100 further includes a cover glass 120 disposed on the image side of the fifth lens L5 and having an object-side surface S11 and an image-side surface S12.

Table 21 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 lens system 100 of example 8, wherein the unit of the radius of curvature, thickness, and effective focal length of each lens is millimeters (mm); table 22 shows the values of relevant parameters of the lens system 100 given in example 8.

TABLE 21

TABLE 22

Fig. 16 shows a longitudinal spherical aberration graph, an astigmatism graph, and a distortion graph, respectively, of the lens system 100 of example 8, the reference wavelength of the lens system 100 being 587.56 nm. Wherein the longitudinal spherical aberration plots show the convergent focus shifts of light rays having wavelengths of 435.83nm, 479.99nm, 546.07nm, 587.56nm, and 656.27nm through lens system 100; the astigmatism graphs show the meridional and sagittal curvature of field of a light ray with a wavelength of 587.56nm after passing through the lens system 100; the distortion plot shows the distortion for different image heights for light having a wavelength of 587.56nm after passing through the lens system 100. As can be seen from fig. 16, the lens system 100 according to embodiment 8 can achieve good imaging quality.

Example 9

A lens 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 view of a lens system 100 of embodiment 9 of the present application.

As shown in fig. 17, the lens 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 and an image plane S13.

The fourth lens element L4 with positive refractive power has a spherical object-side surface S7 and a spherical image-side surface S8, wherein the object-side surface S7 is concave and the image-side surface S8 is convex.

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 at a paraxial region thereof and the image-side surface S10 is convex at a paraxial region thereof.

Table 23 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 lens system 100 of example 9, wherein the unit of the radius of curvature, thickness, and effective focal length of each lens is millimeters (mm); table 24 shows high-order term coefficients that can be used for the lens aspherical surfaces S9 to S10 in example 9, wherein the aspherical surface type can be defined by formula (1) given in example 1; table 25 shows the values of relevant parameters of the lens system 100 given in example 9.

TABLE 23

Watch 24

TABLE 25

Fig. 18 shows a longitudinal spherical aberration graph, an astigmatism graph, and a distortion graph, respectively, of the lens system 100 of example 9, the reference wavelength of the lens system 100 being 587.56 nm. Wherein the longitudinal spherical aberration plots show the convergent focus shifts of light rays having wavelengths of 435.83nm, 479.99nm, 546.07nm, 587.56nm, and 656.27nm through lens system 100; the astigmatism graphs show the meridional and sagittal curvature of field of a light ray with a wavelength of 587.56nm after passing through the lens system 100; the distortion plot shows the distortion for different image heights for light having a wavelength of 587.56nm after passing through the lens system 100. As can be seen from fig. 18, the lens system 100 according to embodiment 9 can achieve good imaging quality.

As shown in fig. 19, the present application further provides an image capturing module 200, which includes the lens system 100 (shown in fig. 1) as described above; and a light sensing element 210, the light sensing element 210 being disposed on the image side of the lens system 100, the light sensing surface of the light sensing element 210 coinciding with the image forming surface S13. Specifically, the photosensitive element 210 may be a Complementary Metal Oxide Semiconductor (CMOS) image sensor or a Charge-coupled Device (CCD) image sensor.

The image capturing module 200 can capture an image with a large depth of field, a high pixel and a wide viewing angle by using the lens 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 system can be used as a mobile phone camera, a vehicle-mounted camera, a monitoring camera or an endoscope and the like.

As shown in fig. 20, the image capturing module 200 can be used as a vehicle-mounted camera in the driving device 300. Steering device 300 may be an autonomous vehicle or a non-autonomous vehicle. The image capturing module 200 can be used as a front camera, a rear camera or a side camera of the driving device 300. Specifically, the driving device 300 includes a vehicle body 310, and the image capturing module 200 is mounted at any position of the vehicle body 310, such as a left rear view mirror, a right rear view mirror, a rear box, a front light, and a rear light, so as to obtain a clear environment image around the vehicle body 310. In addition, still be provided with display screen 320 among the controlling device 300, display screen 320 installs in automobile body 310, and gets for instance module 200 and display screen 320 communication connection, gets for instance the image information that module 200 obtained and can transmit and show to display screen 320 in to make the driver can obtain more complete peripheral image information, improve the safety guarantee when driving.

In particular, in some embodiments, the image capturing module 200 can be applied to an auto-driving vehicle. With reference to fig. 20, the image capturing module 200 is mounted at any position on the body of the automatic driving vehicle, and specifically, reference may be made to the mounting position of the image capturing module 200 in the driving device 300 according to the above embodiment. For an auto-driven vehicle, the image capturing module 200 can also be mounted on the top of the vehicle body. At this time, by installing a plurality of image capturing modules 200 on the autonomous vehicle to obtain environment information of a 360 ° view angle around the vehicle body 310, the environment information obtained by the image capturing modules 200 is transmitted to the analysis processing unit of the autonomous vehicle to analyze the road condition around the vehicle body 310 in real time. By adopting the image capturing module 200, the accuracy of the identification and analysis of the analysis processing unit can be improved, and the safety performance during automatic driving is improved.

As shown in fig. 21, the present application further provides an electronic device 400, which includes a housing 410 and the image capturing module 200 as described above, wherein the image capturing module 200 is mounted on the housing 410. Specifically, the image capturing module 200 is disposed in the housing 410 and exposed from the housing 410 to obtain an image, the housing 410 can provide protection for the image capturing module 200, such as dust prevention, water prevention, falling prevention, and the like, and the housing 410 is provided with a hole corresponding to the image capturing module 200, so that light rays can penetrate into or out of the housing through the hole.

The electronic device 400 can capture an image with a wide viewing angle, a high pixel, and a wide depth of field by using the image capturing module 200. In other embodiments, the electronic device 400 is further provided with a corresponding processing system, and the electronic device 400 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.

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

the lens comprises a first lens element with negative refractive power, a second lens element with negative refractive power and a third lens element with negative refractive power, wherein the image side surface of the first lens element is concave;

a second lens element with positive refractive power;

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

a fourth lens element with positive refractive power having a convex image-side surface;

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

a diaphragm disposed at an object side of the lens system or between the first lens and the fifth lens;

the lens system satisfies the following relation:

0.5＜f12/f＜2.5；

wherein f12 denotes a combined focal length of the first and second lenses, and f denotes an effective focal length of the lens system.

2. The lens system according to claim 1, wherein an object-side surface and/or an image-side surface of at least one of the first to fifth lenses is an aspherical surface.

3. The lens system of claim 1,

an infrared filter is arranged between the fifth lens and the imaging surface of the lens system; alternatively, the first and second electrodes may be,

and the object side surface or the image side surface of one of the first lens to the fifth lens is plated with an infrared filter film.

4. The lens system of claim 1, wherein the lens system satisfies the following relationship:

-2＜f3/f＜-0.5；

where f3 denotes an effective focal length of the third lens.

5. The lens system of claim 1, wherein the lens system satisfies the following relationship:

2＜f4/CT4＜5；

where f4 denotes an effective focal length of the fourth lens, and CT4 denotes a thickness of the fourth lens on an optical axis.

6. The lens system of claim 1, wherein the lens system satisfies the following relationship:

1＜f5/f＜4；

where f5 denotes an effective focal length of the fifth lens.

7. The lens system of claim 1, wherein the lens system satisfies the following relationship:

-3.5＜f1/RS2＜0；

where f1 denotes an effective focal length of the first lens, and RS2 denotes a radius of curvature of an image side surface of the first lens at an optical axis.

8. The lens system of claim 1, wherein the lens system satisfies the following relationship:

0＜(D12+D23)/f＜3；

wherein D12 represents a distance on the optical axis from the image-side surface of the first lens to the object-side surface of the second lens, and D23 represents a distance on the optical axis from the image-side surface of the second lens to the object-side surface of the third lens.

9. The lens system of claim 1, wherein the lens system satisfies the following relationship:

5＜|f1/CT1-f2/CT2|＜12；

wherein f1 denotes an effective focal length of the first lens, f2 denotes an effective focal length of the second lens, CT1 denotes a thickness of the first lens on an optical axis, and CT2 denotes a thickness of the second lens on the optical axis.

10. The lens system of claim 1, wherein the lens system satisfies the following relationship:

18＜|RS5-RS6|/CT3＜28；

wherein RS5 denotes a radius of curvature of an object-side surface of the third lens at an optical axis, RS6 denotes a radius of curvature of an image-side surface of the third lens at the optical axis, and CT3 denotes a thickness of the third lens on the optical axis.

11. The lens system of claim 1, wherein the lens system satisfies the following relationship:

0＜(CT3+CT4)/CT5＜3；

CT3 denotes a thickness of the third lens on an optical axis, CT4 denotes a thickness of the fourth lens on an optical axis, and CT5 denotes a thickness of the fifth lens on an optical axis.

12. The lens system of claim 1, wherein the lens system satisfies the following relationship:

50deg＜(FOV*f)/ImgH＜70deg；

wherein FOV represents a diagonal field angle of the lens system, and ImgH represents a diagonal length of an effective pixel region on an imaging plane of the lens system.

13. The lens system of claim 1, wherein the lens system satisfies the following relationship:

Nd3-Nd5＞0；

wherein Nd3 denotes a d-optical refractive index of the third lens, and Nd5 denotes a d-optical refractive index of the fifth lens.

14. The lens system of claim 1, wherein the lens system satisfies the following relationship:

Vd5-Vd3＞30；

wherein Vd3 denotes a d-ray abbe number of the third lens, and Vd5 denotes a d-ray abbe number of the fifth lens.

15. The lens system of claim 1, wherein the lens system satisfies the following relationship:

0＜BFL/TTL＜1；

wherein BFL represents an optical back focus of the lens system, and TTL represents a distance on an optical axis from the first lens to an imaging surface of the lens system.

16. An image capturing module, comprising the lens system as claimed in any one of claims 1 to 15 and a photosensitive element, wherein the photosensitive element is disposed on an image side of the lens system.

17. An electronic device, comprising a housing and the image capturing module as claimed in claim 16, wherein the image capturing module is mounted on the housing.

18. A driving apparatus, comprising a vehicle body and the image capturing module as claimed in claim 16, wherein the image capturing module is disposed on the vehicle body to obtain the environmental information around the vehicle body.