CN113050252A - Optical lens, camera module and terminal - Google Patents

Optical lens, camera module and terminal Download PDF

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Publication number
CN113050252A
CN113050252A CN201911403975.8A CN201911403975A CN113050252A CN 113050252 A CN113050252 A CN 113050252A CN 201911403975 A CN201911403975 A CN 201911403975A CN 113050252 A CN113050252 A CN 113050252A
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lens
optical lens
imaging
image
optical
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CN201911403975.8A
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CN113050252B (en
Inventor
王恒
叶海水
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Huawei Technologies Co Ltd
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Huawei Technologies Co Ltd
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Priority to CN201911403975.8A priority Critical patent/CN113050252B/en
Priority to CN202210745636.3A priority patent/CN115220184A/en
Priority to CN202210746901.XA priority patent/CN115236832B/en
Publication of CN113050252A publication Critical patent/CN113050252A/en
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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00—Optical objectives specially designed for the purposes specified below
    • G02B13/001—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras
    • G02B13/0015—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design
    • G02B13/002—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design having at least one aspherical surface
    • G02B13/0045—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design having at least one aspherical surface having five or more lenses
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00—Optical objectives specially designed for the purposes specified below
    • G02B13/001—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras
    • G02B13/0055—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras employing a special optical element
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00—Optical objectives specially designed for the purposes specified below
    • G02B13/18—Optical objectives specially designed for the purposes specified below with lenses having one or more non-spherical faces, e.g. for reducing geometrical aberration
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N13/00—Stereoscopic video systems; Multi-view video systems; Details thereof
    • H04N13/20—Image signal generators
    • H04N13/204—Image signal generators using stereoscopic image cameras

Abstract

The application provides an optical lens, a camera module and a terminal. The lens in the optical lens for imaging is provided with at least one non-rotational symmetric lens, the non-rotational symmetric lens can adjust the symmetric relation of the imaging area of the optical lens to be two-axis symmetry, namely the two symmetric axes of the imaging area are two, the two symmetric axes respectively extend along the first direction and the second direction, so that the optical lens comprising the non-rotational symmetric lens generates contraction distortion along the first direction and/or contraction distortion along the second direction when imaging a three-dimensional scene, the stretching deformation generated when imaging an edge object of the three-dimensional scene can be corrected exactly, meanwhile, the deformation along the two directions can keep straight lines in an image horizontal and vertical and still keep the straight lines, the contraction distortion is not easy to find, and better imaging is obtained.

Description

Optical lens, camera module and terminal
Technical Field
The embodiment of the application relates to the field of lenses, in particular to an optical lens, a camera module and a terminal.
Background
When the lens is used to capture an image, the edge image is often distorted. For example, in a scene such as a group photo, an edge person may be deformed, and may look fattened or stretched. This phenomenon is more evident in the process of shooting or recording with a wide-angle lens having a large imaging field of view.
Referring to fig. 1, fig. 1 is a schematic diagram illustrating an optical path principle when an image of a three-dimensional scene is captured through an optical lens. As can be seen from fig. 1, the edge of the image captured through the lens is deformed regardless of the imaging distortion, and the deformation and the objective projection relationship cause the deformation of the three-dimensional object and the poor image quality. Specifically, fig. 1 includes a lens 1, an object to be imaged a, an object to be imaged B, and an object to be imaged C located on an object side of the lens 1, and an image a ', an image B ', and an image C ' located on an object side of the lens 1. The object A to be imaged, the object B to be imaged and the object C to be imaged are spherical structures with the same size. The object B to be imaged and the object C to be imaged are respectively positioned at two sides of the object A to be imaged. The object to be imaged A is over against the lens A, and the object to be imaged B and the object to be imaged C are both positioned at the edge of the imaging visual angle of the lens 1. The image B ' formed by the object B to be imaged and the image C ' formed by the object C to be imaged are respectively positioned at two sides of the image A ' formed by the object A to be imaged. As can be seen from the figure, the sizes of the images formed by the object to be imaged a, the object to be imaged B, and the object to be imaged C with the same size are different, and the image of the object to be imaged B and the object to be imaged C closer to the edge of the imaging viewing angle is larger than the image of the object to be imaged a facing the lens 1, that is, the object to be imaged located at the edge of the imaging viewing angle is stretched.
Disclosure of Invention
The embodiment of the application provides an optical lens, camera module including the optical lens and terminal including the camera module, and aims to avoid the edge of an image acquired by the optical lens from deforming and obtain a high-quality image.
In a first aspect, an optical lens is provided. The optical lens comprises a plurality of lenses arranged from an object side to an image side, wherein the plurality of lenses comprises at least one non-rotation symmetrical lens, the non-rotation symmetrical lens is used for adjusting the symmetry characteristic of an imaging area of the optical lens to be two-axis symmetrical, so that the three-dimensional scene is imaged through the optical lens to generate contraction distortion along a first direction and/or contraction distortion along a second direction, and the first direction is vertical to the second direction.
The lens in the optical lens for imaging is provided with at least one non-rotational symmetric lens, the non-rotational symmetric lens can adjust the symmetric relation of the imaging area of the optical lens to be two-axis symmetry, namely the two symmetric axes of the imaging area are two, the two symmetric axes respectively extend along the first direction and the second direction, so that the optical lens comprising the non-rotational symmetric lens generates contraction distortion along the first direction and/or contraction distortion along the second direction when imaging a three-dimensional scene, the stretching deformation generated when imaging an edge object of the three-dimensional scene can be corrected exactly, meanwhile, the deformation along the two directions can keep straight lines in an image horizontal and vertical and still keep the straight lines, the contraction distortion is not easy to find, and better imaging is obtained.
In some embodiments, the non-rotationally symmetric lens includes an object side surface and an image side surface, the object side surface and/or the image side surface being a non-rotationally symmetric surface, the non-rotationally symmetric surface satisfying the formula:
Figure BDA0002343464480000011
wherein z is the optical surface rise; r is the height of radius in the direction of the optical axis, wherein r2＝x2+y2(ii) a c is the radius of curvature; k is the cone coefficient; a. theiIs a polynomial coefficient; eiIs a power series in the x and y directions;
Figure BDA0002343464480000021
the coordinates of each position of the object side surface and the image side surface of the non-rotational symmetric lens can be calculated through the formula, so that the required non-rotational symmetric lens is designed.
In some embodiments, the non-rotationally symmetric lens has two planes of symmetry, one of the planes of symmetry is parallel to the first direction, and the other one of the planes of symmetry is parallel to the second direction, so that the non-rotationally symmetric lens can adjust the symmetry relationship of the imaging area of the optical lens to be two-axis symmetry, so that the three-dimensional scene is imaged by the optical lens to generate the shrinkage distortion along the first direction and/or the shrinkage distortion along the second direction.
In some embodiments, the non-rotationally symmetric lens is adjacent to an image side of the optical lens relative to the other lenses. The more the image side of the optical lens is, the more the work of adjusting the optical path is, the more important the adjustment of the optical effect is, and when the lens close to the image side of the optical lens is set as the non-rotationally symmetrical lens, the better effect of correcting the tensile deformation generated when the object at the edge of the three-dimensional scene is imaged can be realized. And the non-rotation symmetrical lens is closer to the image side of the optical lens relative to other lenses of the optical lens, so that the non-rotation symmetrical lens can correspondingly correct the aberration generated by other lenses on the object side of the non-rotation symmetrical lens, and a better imaging effect is obtained.
In some embodiments, the optical lens gradually increases the deformation amount of the imaging generating the contraction distortion in the first direction from the middle deformation position to the edge of the imaging field of view, and the optical lens gradually increases the deformation amount of the imaging generating the contraction distortion in the second direction from the middle deformation position to the edge of the imaging field of view.
Because the tensile deformation of the three-dimensional scene under the traditional optical lens with the rotationally symmetric lens in the imaging direction and the stretching deformation from the middle deformation position to the edge in the second direction are gradually increased, the optical lens with the rotationally asymmetric lens is adjusted to enable the deformation amount of the imaging contraction distortion in the first direction to be gradually increased from the middle deformation position to the edge of the imaging field of view, and the deformation amount of the imaging contraction distortion in the second direction is gradually increased from the middle deformation position to the edge of the imaging field of view, so that each position of the imaging can be correspondingly corrected to obtain better imaging.
In some embodiments, the optical lens makes deformation amounts of the contraction distortion that the imaging generates at the same position in the first direction and at different positions in the second direction the same; the optical lens enables the imaging to be generated at the same position in the second direction and the deformation amount of the contraction distortion at different positions in the first direction to be the same, so that the contraction degree of the imaging by the optical lens corresponds to the stretching degree of the imaging by the rotationally symmetric lens, the contraction distortion of the optical lens can correspondingly correct each position of the imaging, the straight line in the corrected imaging can still be basically horizontal, flat and vertical, obvious bending cannot be generated, the general judgment standard of a user for distortion-free imaging is met, and better imaging is obtained.
In some embodiments, the optical lens enables the optical distortion generated by imaging along the first direction and/or along the second direction to be not less than 3%, so that the tensile deformation generated by imaging of the edge object of the three-dimensional scene can be sufficiently corrected, the influence of deformation of the two-dimensional scene can be reduced as much as possible, and better imaging quality can be obtained.
In some embodiments, the optical lens enables the TV distortion along the first direction and the TV distortion along the second direction generated by imaging to be not more than 1%, the TV distortion is small, and the bending deformation of the image of the optical lens after being corrected is not obvious, so that a good imaging effect can be obtained.
In some embodiments, an image plane distance corresponding to infinity from an object side surface of the first lens to the object is a total length TTL of the lens group, a half length ImgH of a diagonal line of an effective pixel area of an imaging plane of the lens group satisfies a condition: TTL/ImgH is less than or equal to 1.50. When TTL/ImgH is less than or equal to 1.50, it can be ensured that the total lens group length TTL of the optical lens 10 is small, and the half length of the diagonal line of the effective pixel area of the imaging surface of the lens group is ImgH, so that a high imaging pixel is obtained, and at the same time, the total lens group length TTL of the optical lens 10 is small, thereby facilitating the application of the optical lens 10 in terminal devices such as mobile phones, and realizing the thinning of the terminal devices such as mobile phones.
In some embodiments, the optical lens has a focal length of less than 20 mm. That is, the distance between the lens and the photosensitive element of the optical lens can be small, so that the total length of the lens group system of the optical lens can be small.
In some embodiments, the maximum field angle of the optical lens exceeds 100 °, that is, the optical lens of the present application may be a wide-angle lens or an ultra-wide-angle lens, and has a larger shooting field of view.
In some embodiments, the other lenses are aspheric symmetric surfaces, and the image-side surface and the object-side surface of each lens satisfy the formula:
Figure BDA0002343464480000031
wherein y is the rise of the aspheric surface, r is the radial coordinate of the aspheric surface, c is the vertex curvature of the aspheric surface, K is the conic constant, aiIs the aspheric coefficient and ρ is the normalized axial coordinate.
The coordinates of each position of the object side surface and the image side surface of the non-rotational symmetric lens can be calculated through the formula, so that the required rotational symmetric lens is designed.
In a second aspect, a camera module is provided, where the camera module includes a photosensitive element and an optical lens, the photosensitive element is located on an image side of the optical lens, and light is projected onto the photosensitive element after passing through the optical lens.
The optical image obtained after passing through the optical lens is converted into an electric signal through the photosensitive element, and then subsequent steps such as image processing and the like are carried out, so that an image with good imaging quality can be obtained. In addition, the optical lens corrects the stretching deformation of the edge object of the three-dimensional scene, and better imaging quality can be obtained. Consequently, the camera module of this application also can realize good formation of image quality.
In some embodiments, the photosensitive element has a square shape, and the photosensitive element includes a first side and a second side perpendicular to each other, the first direction is the same as the extending direction of the first side, and the second direction is the same as the extending direction of the second side.
Because the symmetrical characteristic of this application optical lens's the regional diaxon symmetry of formation of image, the regional shrink distortion of formation of image is along first direction and second direction, and first direction is parallel with photosensitive element's first limit, and the second direction is parallel with photosensitive element's second limit to can make the straight line in the formation of image after the shrink distortion can keep violently flat vertical, the distortion of introduction is difficult to be found, thereby obtains better shooting quality.
In a third aspect, a terminal is provided, where the terminal includes an image processor and a camera module, the image processor is in communication connection with the camera module, the camera module is configured to obtain image data and input the image data into the image processor, and the image processor is configured to process the image data output therefrom.
In the application, the image data of the two camera modules are processed through the image processor, so that better shot pictures or images are obtained. In addition, the optical lens corrects the stretching deformation of the edge object of the three-dimensional scene, and better imaging quality can be obtained. Therefore, the terminal of the application can shoot images with good imaging quality.
Drawings
Fig. 1 is a schematic diagram of the principle of optical paths when an image of a three-dimensional scene is captured through an optical lens.
Fig. 2 is a schematic structural diagram of a terminal according to an embodiment of the present application.
Fig. 3 is a schematic structural diagram of a terminal according to another embodiment of the present application.
Fig. 4 is a schematic view of the imaging principle of the terminal shown in fig. 3.
Fig. 5 is a schematic structural diagram of a camera module according to an embodiment of the present application.
Fig. 6 is a schematic structural diagram of a non-rotationally symmetric lens of an optical lens according to an embodiment of the present application.
Fig. 7 is a schematic cross-sectional view of the non-rotationally symmetric lens of fig. 6 along direction a-a.
Fig. 8 is a schematic cross-sectional view of the non-rotationally symmetric lens of fig. 6 taken along the direction B-B.
Fig. 8a is a symmetrical characteristic of an imaging plane of a conventional optical lens.
Fig. 8b is a symmetrical characteristic of an imaging plane of the optical lens of the present application.
Fig. 9 is a schematic view of an imaging simulation structure of an optical lens according to some embodiments of the present application on an imaging plane.
Fig. 10 is a schematic diagram illustrating a positional relationship between an optical lens and an object to be imaged according to some embodiments of the present application.
Fig. 11 is a schematic imaging diagram of the object to be imaged shown in fig. 10 taken by different optical lenses.
Fig. 12 is an enlarged schematic view of position II in fig. 9.
Fig. 13 is a schematic structural diagram of an optical lens according to an embodiment of the present application.
Detailed Description
The technical solutions in the embodiments of the present application will be described below with reference to the accompanying drawings.
For convenience of understanding, technical terms related to the present application are explained and described below.
Focal length (f), also known as focal length, is a measure of the concentration or divergence of light in an optical system, and refers to the perpendicular distance from the optical center of a lens or lens group to the focal plane when an infinite scene is imaged clearly through the lens or lens group at the focal plane. From a practical point of view it can be understood as the distance of the lens center to the imaging plane. For a fixed-focus lens, the position of the optical center is fixed and unchanged; for a zoom lens, a change in the optical center of the lens results in a change in the focal length of the lens.
Positive refractive power, which may also be referred to as positive refractive power, indicates that the lens has a positive focal length and has the effect of converging light.
Negative refractive power, which may also be referred to as negative refractive power, indicates that the lens has a negative focal length and has a light-diverging effect.
Total Track Length (TTL), which refers to the total length from the end of the optical lens away from the imaging surface to the imaging surface, is a major factor in forming the height of the camera.
The dispersion coefficient is the difference ratio of refractive indexes of the optical material at different wavelengths, and represents the dispersion degree of the material.
A field of view (FOV) is an angle of view formed by two edges of an optical instrument, at which an object image of a measurement target can pass through the maximum range of a lens, with the lens of the optical instrument as a vertex. The size of the field angle determines the field of view of the optical instrument, with a larger field angle providing a larger field of view and a smaller optical magnification.
The optical axis is a ray that passes perpendicularly through the center of the ideal lens. When light rays parallel to the optical axis are incident on the convex lens, the ideal convex lens is that all the light rays converge at a point behind the lens, and the point where all the light rays converge is the focal point.
The object side is defined by the lens, and the side where the object is located is the object side.
And the image side is the side where the image of the shot object is located by taking the lens as a boundary.
The object side surface, the surface of the lens near the object side is called the object side surface.
The surface of the lens near the image side is called the image side surface.
Optical distortion (optical distortion) refers to the difference between the point display positions in distorted images and their positions in an ideal system, and concerns the position shift of points in the microscopic scale.
TV distortion (TV distortion) refers to the height difference between the square edge and the middle edge, and concerns the macroscopic rectangular image distortion.
The application provides a terminal which can be a mobile phone, a tablet, a computer, a video camera, a camera or other equipment with photographing or shooting functions. Referring to fig. 2, fig. 2 is a schematic structural diagram of a terminal 1000 according to an embodiment of the present application. In this embodiment, terminal 1000 is a mobile phone. In other embodiments, terminal 1000 can be a device with an imaging function in other forms, such as a tablet or a camera.
The terminal 1000 includes a camera module 100 and an image processor 200 communicatively coupled to the camera module 100. The camera module 100 is used for acquiring image data and inputting the image data into the image processor 200, so that the image processor 200 processes the image data. The communication connection between the camera module 100 and the image processor 200 may include data transmission through electrical connection such as wire connection, or may also be realized through other data transmission modes such as optical cable connection or wireless transmission.
The function of the image processor 200 is to optimize the digital image signal through a series of complex mathematical algorithm operations, and finally to transmit the processed signal to a display or store the processed signal in a memory. The image processor 200 may be an image processing chip or a Digital Signal Processing (DSP) chip.
In the embodiment shown in fig. 2, the camera module 100 is disposed on the back surface of the terminal 1000, and is a rear camera of the terminal 1000. It is understood that in some embodiments, camera module 100 can also be disposed on a front face of terminal 1000 as a front-facing camera of terminal 1000. The front camera and the rear camera can be used for self-shooting and can also be used for shooting other objects by a photographer.
In some embodiments, there are a plurality of camera modules 100, and the plurality means two or more. The plurality of camera modules 100 can cooperate with each other, thereby achieving a better shooting effect. In the embodiment shown in fig. 2, there are two rear cameras of the terminal 1000, and the two camera modules 100 are both in communication connection with the image processor 200, so as to process the image data of the two camera modules 100 through the image processor 200, so as to obtain better shot pictures or images.
It should be understood that the installation position of the camera module 100 of the terminal 1000 in the embodiment shown in fig. 2 is only illustrative, and in some other embodiments, the camera module 100 can be installed in other positions on the mobile phone. For example, the camera module 100 can be installed in the middle of the upper part of the back of the mobile phone or in the upper right corner; alternatively, the camera module 100 may be disposed not on the main body of the mobile phone, but on a component that is movable or rotatable with respect to the mobile phone, for example, the component may be extended, retracted, or rotated from the main body of the mobile phone. The present application does not limit the installation position of the camera module 100.
Referring to fig. 3 and 4, fig. 3 is a schematic structural diagram of a terminal according to another embodiment of the present application, and fig. 4 is a schematic imaging principle diagram of the terminal shown in fig. 3. In some embodiments, terminal 1000 can further include an analog-to-digital converter (also referred to as A/D converter) 300. The adc 300 is connected between the camera module 100 and the image processor 200. The analog-to-digital converter 300 is configured to convert an analog image signal generated by the camera module 100 into a digital image signal and transmit the digital image signal to the image processor 200, and then the image processor 200 processes the digital image signal, and finally displays an image or an image on a display screen or a display.
In some embodiments, the terminal 1000 further includes a memory 400, the memory 400 is in communication with the image processor 200, and the image processor 200 processes the digital image signal and then transmits the processed image to the memory 400, so that the image can be searched from the memory and displayed on the display screen at any time when the image needs to be viewed later. In some embodiments, the image processor 200 further compresses the processed image digital signal and stores the compressed image digital signal in the memory 400, so as to save the space of the memory 400. It should be noted that fig. 3 is only a schematic structural diagram of the embodiment of the present application, and the position structures of the camera module 100, the image processor 200, the analog-to-digital converter 300, the memory 400, and the like shown in the diagram are only schematic.
Referring to fig. 4, the camera module 100 includes an optical lens 10 and a photosensitive element 20. The photosensitive element 20 is located at the image side of the optical lens 10, and when the camera module 100 works, light reflected by a scene to be imaged is projected to the photosensitive element 20 after passing through the optical lens 10. Specifically, the working principle of the camera module 100 is as follows: the light L reflected by the object is projected to the surface of the light sensing element 20 through the optical lens 10 to generate an optical image, the light sensing element 20 converts the optical image into an electrical signal, i.e., an analog image signal S1 and transmits the converted analog image signal S1 to the analog-to-digital converter 300, so as to be converted into a digital image signal S2 by the analog-to-digital converter 300 to the image processor 200.
The photosensitive element 20 is a semiconductor chip, and includes several hundreds of thousands to several millions of photodiodes on the surface thereof, and generates electric charges when being irradiated by light, thereby completing the conversion of optical signals into electrical signals. Alternatively, the light sensing element 20 may be any device capable of converting an optical signal into an electrical signal. For example, the photosensitive element 20 may be a Charge Coupled Device (CCD) or a complementary metal-oxide semiconductor (CMOS).
The optical lens 10 affects the imaging quality and the imaging effect. The optical lens 10 includes a plurality of lenses 11 arranged from the object side to the image side, and performs imaging mainly by using the refraction principle of the lenses 11. Specifically, light of an object to be imaged forms a sharp image on a focal plane through the optical lens 10, and an image of a subject is recorded through the photosensitive element 20 located on the focal plane. The adjacent lenses 11 may have an air space therebetween or may be disposed in close contact therewith. The primary function of each lens 11 is different, and the best imaging quality is obtained by cooperation between different lenses 11.
In some embodiments, the optical lens 10 further includes a diaphragm 12, and the diaphragm 12 may be disposed on the object side of the plurality of lenses 11, or between lenses close to the object side of the plurality of lenses 11. For example, the diaphragm may be located between a first lens and a second lens close to the object side, or between a second lens and a third lens close to the object side in the plurality of lenses 11. The diaphragm 12 may be an aperture diaphragm for limiting the amount of incident light rays to vary the brightness of the image.
In some embodiments, the optical lens 10 further includes an infrared filter 30, and the infrared filter 30 is located between the photosensitive element 20 and the lens 11 of the optical lens 10. The light refracted by the optical lens 10 is irradiated onto the infrared filter 30 and transmitted to the photosensitive element 20 through the infrared filter 30. The infrared filter can filter out unnecessary light projected onto the photosensitive element 20, and prevent the photosensitive element 20 from generating false color or moire, so as to improve the effective resolution and color reproducibility thereof.
Referring to fig. 5, fig. 5 is a schematic structural diagram of a camera module according to some embodiments of the present disclosure. In some embodiments, the optical lens 10 further includes a lens barrel 10a, the plurality of lenses 11 of the optical lens 10 are fixed in the lens barrel 10a, and the plurality of lenses 11 fixed in the lens barrel 10a are coaxially disposed. In the embodiment of the present application, the plurality of lenses 11 are fixed in the lens barrel 10a, the distance between the lenses 11 is fixed, and the optical lens 10 is a lens with a fixed focal length. In other embodiments of the present application, the multiple lenses 11 of the optical lens 10 can move relatively in the lens barrel 10a to change the distance between the multiple lenses 11, so as to change the focal length of the optical lens 10, and achieve focusing of the optical lens 10. The infrared filter 30 may be fixed to an end of the lens barrel 10a of the optical lens 10 facing the image side.
The camera module 100 further includes a fixing base 50(holder), a circuit board 60, and the like.
The fixing base 50 includes an accommodating cavity, the optical lens 10 is accommodated in the accommodating cavity of the fixing base 50 and fixed to the cavity wall of the accommodating cavity, and the optical lens 10 is fixed relative to the fixing base 50 and cannot move relative to the fixing base 50. The circuit board 60 is fixed to a side of the fixing base 50 facing away from the optical lens 10. The wiring board 60 is used to transmit electrical signals. The circuit board 60 may be a Flexible Printed Circuit (FPC) or a Printed Circuit Board (PCB), wherein the FPC may be a single-sided flexible board, a double-sided flexible board, a multi-layer flexible board, a rigid flexible board, a hybrid-structured flexible circuit board, or the like. Other components included in the camera module 100 are not described in detail herein. The infrared filter 30 may be fixed to the cavity wall of the fixing base 50 and located between the optical lens 10 and the circuit board 60; alternatively, the support may be supported and fixed above the circuit board 60.
The photosensitive element 20 is fixed to the circuit board 60 by bonding or mounting. The light receiving element 20 is located on the image side of the optical lens 10 and is disposed opposite to the optical lens 10, and an optical image generated by the optical lens 10 can be projected onto the light receiving element 20. In some embodiments, the analog-to-digital converter 300, the image processor 200, the memory 400, etc. are also integrated on the circuit board 60 by means of bonding or mounting, etc., so that the communication connection between the photosensitive element 20, the analog-to-digital converter 300, the image processor 200, the memory 400, etc. is realized through the circuit board 60.
In some embodiments, the lens barrel 10a and the fixed base 50 of the optical lens 10 can move relative to the fixed base 50 to change the distance between the optical lens 10 and the photosensitive element 20. When the focal length of the optical lens 10 changes, the distance between the optical lens 10 and the photosensitive element 20 is adjusted accordingly, so as to ensure the imaging quality of the camera module 100. For example, in some embodiments, the fixing base 50 includes a cavity wall of the receiving cavity provided with an internal thread, an outer wall of the lens barrel 10a is provided with an external thread, and the lens barrel 10a is in threaded connection with the fixing base 50. The lens barrel 10a is driven by the driver to rotate, so that the lens barrel 10a moves in the axial direction relative to the fixed base 50, and the lens 11 of the optical lens 10 is close to or far away from the photosensitive element 20. It is understood that the lens barrel 10a may be connected to the fixed base 50 in other manners and may be moved relative to the fixed base 50. For example, the lens barrel 10a and the fixed base 50 are connected by a slide rail.
In the present application, at least one lens 11 of the plurality of lenses 11 of the optical lens 10 is a non-rotationally symmetric lens. The object side surface and/or the image side surface of the non-rotationally symmetric lens are/is a non-rotationally symmetric surface. Wherein, the object side surface and/or the image side surface of the non-rotational symmetry lens are non-rotational symmetry surfaces: the non-rotational symmetrical lens can be a lens with non-rotational symmetrical surfaces on both the object side surface and the image side surface; or the non-rotational symmetric lens is a lens with the object side surface being a rotational symmetric surface and the image side surface being a non-rotational symmetric surface; or the non-rotational symmetric lens is a lens with the object side surface being a non-rotational symmetric surface and the image side surface being a rotational symmetric surface. Wherein, the rotational symmetry plane can be obtained by line rotation, and the non-rotational symmetry plane can not be obtained by line rotation. Referring to fig. 6, 7 and 8, fig. 6 is a schematic structural diagram of a non-rotationally symmetric lens of an optical lens 10 according to an embodiment of the present disclosure. In fig. 6, the X direction is a first direction, and the Y direction is a second direction. FIG. 7 is a schematic cross-sectional view of the non-rotationally symmetric lens shown in FIG. 6 along the A-A direction, wherein the A-A direction is parallel to the X direction and passes through the optical axis of the lens; FIG. 8 is a cross-sectional view of the non-rotationally symmetric lens shown in FIG. 6 taken along the direction B-B, wherein the cross-section B-B is parallel to the direction Y and passes through the optical axis of the lens. As can be seen, the section A-A of the non-rotationally symmetrical lens taken along the direction A-A is different from the section B-B of the non-rotationally symmetrical lens taken along the direction B-B, i.e., the non-rotationally symmetrical lens cannot be obtained by planar rotation. In this embodiment, the non-rotationally symmetric lenses are symmetrical with respect to the lenses on both sides in the A-A direction, and the non-rotationally symmetric lenses are symmetrical with respect to the lenses on both sides in the B-B direction. In this embodiment, the non-rotationally symmetric lens has two symmetric planes, and one of the symmetric planes is parallel to the first direction and is a plane where the section B-B is located; the other of said symmetry planes is parallel to said second direction and is the plane of section a-a. It will be appreciated that in some other embodiments, the lenses on both sides of the non-rotationally symmetric lens in the A-A direction may also be asymmetric, and the lenses on both sides of the non-rotationally symmetric lens in the B-B direction may also be asymmetric.
The non-rotationally symmetric lenses can enable imaging of a three-dimensional scene through an optical lens 10 including the non-rotationally symmetric lenses to produce a systolic distortion in a first direction and/or a systolic distortion in a second direction. Wherein the first direction is perpendicular to the second direction. In some embodiments, the photosensitive element 20 has a square shape, and the square-shaped photosensitive element 20 includes a first side and a second side perpendicular to each other, wherein the first direction is the same as the extending direction of the first side, and the second direction is the same as the extending direction of the second side. When a three-dimensional scene is imaged, especially when the three-dimensional scene is imaged through a wide-angle lens or an ultra-wide-angle lens, an object at the edge of the three-dimensional scene is more likely to generate stretching deformation. A three-dimensional scene edge object refers to an object located at the edge of the field of view of the optical lens 10 when a three-dimensional scene is captured. For example, a person located at the edge of the field of view of the optical lens 10 when taking a large group photograph. In the embodiment of the present application, the shrinkage distortion along the first direction and/or the shrinkage distortion along the second direction can be generated by imaging after the optical lens 10 including the non-rotationally symmetric lens, and the tensile deformation generated by the object at the edge of the three-dimensional scene can be corrected, so as to obtain high-quality imaging.
At least one non-rotationally symmetrical lens is arranged in the lens of the optical lens for imaging. The symmetrical characteristic of the imaging area of the optical lens is changed through the non-rotational symmetrical lens, and the symmetrical characteristic of the central rotational symmetry is changed into the symmetrical characteristic of two-axis symmetry. Specifically, referring to fig. 8a and 8b, fig. 8a shows the symmetry of the image plane of the conventional optical lens; fig. 8b shows the symmetry characteristic of the image plane of the optical lens 10 of the present application. Each lens of the conventional optical lens is a rotationally symmetric lens, the imaging area of the conventional optical lens is an imaging circle, that is, the imaging area is a circle, the symmetry characteristic of the imaging circle is central rotational symmetry, and the conventional lens is applied such that the direction of the shrinkage distortion generated by imaging shrinks from each direction to the center of the imaging circle (as shown by the arrow direction in fig. 8 a). The imaging area of the optical lens 10 of the present application is square, and the symmetry characteristic is two-axis symmetry, that is, two symmetry axes of the imaging area extend along the first direction and the second direction, the optical lens 10 is applied to make the direction of the shrinkage distortion generated by imaging shrink along the first direction and/or shrink along the second direction (as shown by the arrow in fig. 8 b), and the introduction of the non-rotational symmetric lens makes the shrinkage distortion generated by the imaging of the three-dimensional scene edge object along the first direction and/or the shrinkage distortion generated by the imaging of the three-dimensional scene edge object along the second direction correct the tensile deformation generated during the imaging of the three-dimensional scene edge object, so as to obtain better imaging quality. For example, please refer to fig. 9, wherein the embodiment shown in fig. 9 is a schematic view of an imaging simulation structure of the optical lens 10 of the present application on an imaging plane. Wherein, the solid line grid a is a structure to be imaged, and the structure is a plane structure. The grid formed by connecting the "X" lines in the figure is an imaging simulation diagram after the solid line grid a passes through the optical lens 10. As can be seen from the figure, when imaging is performed by the optical lens 10 including at least one non-rotationally symmetric lens, the optical lens 10 can generate a shrinkage distortion in a first direction and a shrinkage distortion in a second direction in the imaging. Therefore, when the optical lens 10 is applied to shooting a three-dimensional scene, the application of the non-rotationally symmetric lens in the optical lens 10 enables the contraction distortion generated by imaging along the first direction to correct the stretching deformation generated by the three-dimensional scene edge object in the first direction during imaging, and the optical lens 10 enables the contraction distortion generated by imaging along the second direction to correct the stretching deformation generated by the second direction during imaging of the three-dimensional scene edge object, so that the stretching deformation generated by imaging of the three-dimensional scene edge object during shooting the three-dimensional scene can be reduced. Meanwhile, due to the symmetrical characteristic of two-axis symmetry of the imaging area of the optical lens 10, contraction distortion of the imaging area is along the first direction and the second direction, the first direction is parallel to the first edge of the photosensitive element 20, and the second direction is parallel to the second edge of the photosensitive element 20, so that straight lines in imaging after the contraction distortion can be kept horizontal and vertical, introduced distortion is not easy to find, and better shooting quality is obtained.
For example, please refer to fig. 10 and 11, fig. 10 is a schematic diagram illustrating a position relationship between an optical lens and an object to be imaged according to some embodiments of the present application. Fig. 11 is a schematic imaging diagram of the object to be imaged shown in fig. 10 captured by different optical lenses. The objects to be imaged are an object A to be imaged, an object B to be imaged, an object C to be imaged, an object D to be imaged and an object E to be imaged respectively. The object A to be imaged is right opposite to the optical lens and is positioned in the middle of the visual field of the optical lens. The object to be imaged B and the object to be imaged C of the object to be imaged are respectively located at the edge of a view field of the optical lens in the first direction and are respectively located at two sides of the object to be imaged A. The object to be imaged D and the object to be imaged E of the object to be imaged are respectively located at the edge of the view field of the optical lens in the second direction and are respectively located on two sides of the object to be imaged A.
The dotted lines in fig. 11 show images obtained on the photosensitive element 20 when the object to be imaged a, the object to be imaged B, the object to be imaged C, the object to be imaged D, and the object to be imaged E are photographed by a conventional general optical lens. The image of the object to be imaged A is an image A1, the image of the object to be imaged B is an image B1, the image of the object to be imaged C is an image C1, the image of the object to be imaged D is an image D1, and the image of the object to be imaged E is an image E1. The solid line shows images obtained on the photosensitive element 20 when the object a to be imaged, the object B to be imaged, the object C to be imaged, the object D to be imaged, and the object E to be imaged are photographed by the optical lens 10 in the present embodiment, where the image obtained by the object a to be imaged is an image a2, the image obtained by the object B to be imaged is an image B2, the image obtained by the object C to be imaged is an image C2, the image obtained by the object D to be imaged is an image D2, and the image obtained by the object E to be imaged is an image E2. As can be easily seen from the figure, when the object to be imaged B, the object to be imaged C, the object to be imaged D, and the object to be imaged E located at the edge of the field of view are photographed by a common optical lens, the objects to be imaged B, C, D, and E will be subjected to tensile deformation. Since the optical lens 10 of the present embodiment can correct the tensile deformation generated in the first direction when the three-dimensional scene edge object is imaged by causing the imaging to generate the contraction distortion in the first direction, and can correct the tensile deformation generated in the second direction when the three-dimensional scene edge object is imaged by causing the imaging to generate the contraction distortion in the second direction, the tensile deformation of the three-dimensional scene edge object can be appropriately corrected, and the imaging indicated by the solid line can be obtained.
In some other embodiments, when the three-dimensional scene is imaged with mainly tensile deformation in the first direction (for example, X direction in fig. 6), the non-rotationally symmetric lens may be designed such that the optical lens 10 including the non-rotationally symmetric lens can generate shrinkage distortion in the first direction in the three-dimensional scene imaging, wherein the shrinkage distortion in the first direction generated by the optical lens 10 including the non-rotationally symmetric lens in the three-dimensional scene imaging can correct the tensile deformation in the first direction in the three-dimensional scene edge object imaging, so as to obtain better imaging. Alternatively, when the three-dimensional scene is imaged and mainly generates the stretching deformation in the second direction (for example, Y direction in fig. 6), the non-rotationally symmetric lens may be designed, so that the optical lens 10 including the non-rotationally symmetric lens can generate the shrinking distortion in the second direction along the three-dimensional scene, wherein the shrinking distortion in the second direction generated by the optical lens 10 including the non-rotationally symmetric lens can correct the stretching deformation in the second direction generated by the three-dimensional scene imaging, so as to obtain better imaging.
Referring to fig. 9 and 12, fig. 12 is an enlarged schematic view of a position II in fig. 9. The tensile deformation of the three-dimensional scene from the middle deformation position to the edge of the image formed under the traditional optical lens with the lens being rotationally symmetric in the first direction is gradually increased, wherein the middle deformation position is the position where the middle area of the image starts to deform. In the embodiment of the application, by introducing the rotationally symmetric lens, the deformation amount of the optical lens 10 generating the shrinkage distortion in the first direction is gradually increased from the middle deformation position to the edge of the imaging field, that is, L5 is greater than L6, and L7 is greater than L8; the deformation amount of the optical lens 10 causing the contraction distortion in the second direction to the imaging gradually increases from the middle deformation position to the edge of the imaging field of view, i.e., L1 is greater than L3, and L2 is greater than L4. Therefore, the optical lens 10 including the non-rotationally symmetric lens can perform corresponding correction on each position of the image to obtain a better image.
The optical lens 10 of the embodiment of the present application makes deformation amounts of the contraction distortion that the imaging generates at the same position in the first direction and at different positions in the second direction substantially the same, that is, L5 is substantially equal to L7, and L6 is substantially equal to L8; the optical lens 10 makes the deformation amount of the contraction distortion of the image generated at the same position in the second direction and at different positions in the first direction substantially the same, i.e., L1 is substantially equal to L2, and L3 is substantially equal to L4. Therefore, the contraction degree of the optical lens 10 to the imaging corresponds to the stretching degree of the rotationally symmetric lens to the imaging, so that the contraction distortion of the optical lens 10 can correspondingly correct each position of the imaging, and the straight line in the corrected imaging can still basically ensure the horizontal, flat and vertical direction, no obvious bending can be generated, the general judgment standard of a user on distortion-free imaging is met, and better imaging is obtained.
In some embodiments, at least the image-side surface of the non-rotationally symmetric lens is a non-rotationally symmetric surface, of the image-side surface and the object-side surface of the non-rotationally symmetric lens. Because the image side surface is closer to the photosensitive element, the light ray is better converged on the image side surface than the object side surface, and when the image side surface is set to be a non-rotational symmetry surface, the effect of better correcting the stretching deformation generated when the object at the edge of the three-dimensional scene is imaged can be realized relative to the case that only the object side surface is set to be a non-rotational symmetry surface.
In some embodiments, the non-rotationally symmetric lens is closer to an image side of the optical lens relative to other lenses of the optical lens. The more the image side of the optical lens is, the more the work of adjusting the optical path is, the more important the adjustment of the optical effect is, and when the lens close to the image side of the optical lens is set as the non-rotationally symmetrical lens, the better effect of correcting the tensile deformation generated when the object at the edge of the three-dimensional scene is imaged can be realized. And the non-rotation symmetrical lens is closer to the image side of the optical lens relative to other lenses of the optical lens, so that the non-rotation symmetrical lens can correspondingly correct the aberration generated by other lenses on the object side of the non-rotation symmetrical lens, and a better imaging effect is obtained.
In the present application, the object-side surface or the image-side surface of the multi-piece lens 11 of the optical lens 10 may be a spherical surface or an aspherical surface. In some embodiments of the present application, the lenses 11 of the optical lens 10 are all aspheric lenses, and the object-side surface and/or the image-side surface of the aspheric lenses are aspheric free-form surfaces. The aspheric lens has the characteristics that: the curvature varies continuously from the center of the lens to the edge of the lens. Unlike a spherical lens having a constant curvature from the lens center to the lens periphery, an aspherical lens has a better curvature radius characteristic, and has advantages of improving distortion aberration and improving astigmatic aberration. After the aspheric lens is adopted, the aberration generated during imaging can be eliminated as much as possible, thereby improving the imaging quality.
In the embodiment of the application, the non-rotational symmetry plane of the non-rotational symmetry lens is also a free curved surface with an aspheric surface, and the non-rotational symmetry plane satisfies the formula:
Figure BDA0002343464480000101
wherein z (x, y) is the optical surface rise; k is a conic coefficient; c is the radius of curvature; r is the radius height in the optical axis direction, wherein r2 ═ x2+ y 2; ai is a polynomial coefficient; ei is a power series in the x, y directions. In particular, the method comprises the following steps of,
Figure BDA0002343464480000102
in the present embodiment, the object-side surface and the image-side surface of the lenses 11 of the optical lens 100 except the rotationally symmetric lens are rotationally symmetric free-form surfaces. Wherein, the rotational symmetry free-form surface satisfies the formula:
Figure BDA0002343464480000111
wherein z (x, y) is the optical surface rise; k is a conic coefficient; c is the radius of curvature; r is the radius height in the optical axis direction; r is2＝x2+y2；αiIs a polynomial coefficient; rhoiIs a normalized radial coordinate.
Through the above relation, the lenses 11 with different aspheric surfaces are obtained, so that different optical effects can be realized by different lenses 11, and a good shooting effect can be realized through the matching of different aspheric surface lenses 11.
In some embodiments of the present application, the optical lens 100 makes optical distortion generated by imaging along a first direction (e.g., an X direction in fig. 11) and along a second direction (e.g., a Y direction in fig. 11) not less than 3%, so as to sufficiently correct tensile deformation generated by imaging of an edge object of a three-dimensional scene, so as to weaken influence of deformation of a two-dimensional scene as much as possible, thereby obtaining better imaging quality. Because the optical lens 10 of the non-rotationally symmetric lens can change the symmetric characteristic of the imaging area of the optical lens 10 into two-axis symmetry, the first direction and the second direction generated by imaging are contracted and distorted, so that the optical lens 10 including the non-rotationally symmetric lens can correspondingly correct the stretching deformation of each position of the imaging. Because the imaging area of the optical lens 10 has the symmetrical characteristic of two axes, the edge of the image after correction has no obvious bending deformation, and the TV distortion is ensured to be smaller, thereby obtaining better imaging quality. In the present embodiment, the TV distortion of the optical lens is not greater than 1%, that is, the TV distortion in the first direction (for example, X direction in fig. 11) and the TV distortion in the second direction (for example, Y direction in fig. 11) generated by the imaging by the optical lens 100 are not greater than 1%, the TV distortion is small, and the bending deformation of the image formed by the optical lens 10 after the image forming is corrected is not obvious, so that a good imaging effect can be obtained.
In some embodiments of the present application, the total lens group length TTL of the optical lens 10 and the half length of the diagonal line of the effective pixel area of the imaging surface of the optical lens group are ImgH, which satisfy the following conditions: TTL/ImgH is less than or equal to 1.50. When TTL/ImgH is less than or equal to 1.50, it can be ensured that the total lens group length TTL of the optical lens 10 is small, and the half length of the diagonal line of the effective pixel area of the imaging surface of the lens group is ImgH, so that a high imaging pixel is obtained, and at the same time, the total lens group length TTL of the optical lens 10 is small, thereby facilitating the application of the optical lens 10 in terminal devices such as mobile phones, and realizing the thinning of the terminal devices such as mobile phones. In some embodiments, TTL/ImgH can also be greater than 1.50. However, when TTL/ImgH is greater than 1.50, the total lens length TTL of the optical lens is long, and therefore, the TTL is not suitable for being applied to a mobile phone, a tablet, or other terminals that require thinning as much as possible.
In some embodiments, the focal length of the optical lens 10 may be less than 20mm, i.e., the distance between the lens 11 of the optical lens 10 and the photosensitive element 20 can be smaller, thereby enabling the total length of the lens group system of the optical lens to be smaller. In some embodiments, the maximum field angle of the optical lens 10 may exceed 100 °, that is, the optical lens 10 may be a wide-angle lens or a super-wide-angle lens, and at least one non-rotationally symmetric lens is disposed in the plurality of lenses 11 of the optical lens 10 to reduce the tensile deformation of the imaged edge, so as to ensure that a picture taken by the wide-angle lens or the super-wide-angle lens can also have a better imaging effect.
Referring to fig. 13, fig. 13 is a schematic structural diagram of an optical lens 10 according to an embodiment of the present disclosure. In this embodiment, the optical lens 10 includes six lenses 11 arranged in order from the object side to the image side. Adjacent lenses 11 each have an air space therebetween. The image with better imaging effect is formed by matching the six lenses 11. It is understood that in other embodiments, the number of the lenses 11 of the optical lens 10 may be other, for example, five or seven lenses 11 of the optical lens 10 may be provided. The six lenses 11 are a first lens 111, a second lens 112, a third lens 113, a fourth lens 114, a fifth lens 115 and a sixth lens 116 in order from an object side to an image side, and each lens 11 is coaxially disposed. It is understood that the plurality of lenses 11 of the present application are all lenses 11 having positive or negative refractive power, and when a plane mirror is inserted between the plurality of lenses 11, the plane mirror does not function as the lens 11 of the optical lens of the present application. For example, when a plane mirror is inserted between the fourth lens 114 and the fifth lens 115, the plane mirror cannot be calculated as the fifth lens 11 according to the embodiment of the present application. In the present embodiment, the diaphragm 12 is disposed between the second mirror 112 and the third mirror 113.
The first lens element 111 with positive refractive power has a concave object-side surface and a convex image-side surface; the second lens element 112 with negative refractive power has a convex object-side surface and a convex image-side surface; the third lens element 113 with positive refractive power has a convex object-side surface and a concave image-side surface; the fourth lens element 114 with positive refractive power has a concave object-side surface and a concave image-side surface; the fifth lens element 115 with negative refractive power has a concave object-side surface and a concave image-side surface; the sixth lens element 116 with positive refractive power has a concave object-side surface and a convex image-side surface. The object-side surface and the image-side surface of the first lens 111, the second lens 112, the third lens 113, the fourth lens 114, and the fifth lens 115 are both rotationally symmetric free-form surfaces, and the object-side surface and the image-side surface of the sixth lens 116 are both non-rotationally symmetric free-form surfaces.
In the embodiment of the present application, different lenses 11 of the optical lens 10 can respectively perform different functions, so that the optical lens 10 with good imaging quality can be obtained by matching the lenses 11. Specifically, in the present embodiment, the first lens 111 has positive refractive power, and can achieve the purpose of increasing the angle of field of view; the second lens element 112 with negative refractive power can converge light; the second lens 112 and the fourth lens 114 are both meniscus structures, and can form a double-gauss-like structure, which is helpful for improving the aberration of the optical lens 10, so as to improve the imaging quality of the optical lens 10; the second lens 112 and the third lens 113 cooperate to correct chromatic aberration; the fifth lens element 115 has negative refractive power, and is used for expanding light rays and increasing the imaging image height; the sixth lens 116 can increase the system throughput and correct the distortion. Here, only the function of each lens 11 in the present embodiment is described, but in other embodiments of the present application, each lens 11 can perform other functions, and the present invention is not limited thereto.
The distribution of the positive and negative refractive powers is met, the deflection angle of light rays is favorably reduced, the purpose of increasing the view field angle is achieved by utilizing a reverse telephoto principle, and particularly, compared with a telephoto structure of the first lens adopting a positive lens, the first lens has the negative refractive power, so that the system can increase the view field angle more easily.
In this embodiment, the first lens 111, the second lens 112, the third lens 113, the fourth lens 114, the fifth lens 115, and the sixth lens 116 are made of resin, and the infrared filter 30 is made of glass. The resin material is easy to be molded; the glass material has small expansion coefficient, stable performance under large temperature difference change, and large refractive index range, and can obtain a lens with thin thickness and good imaging quality as required. In some embodiments, the lens 11 may also be made of glass, and the specific application material of different lenses 11 may be reasonably matched according to the needs in consideration of the manufacturing cost, efficiency and optical effect.
According to the above relational expressions, the design parameters of each lens of the optical lens according to the present embodiment are shown in tables 1, 2, and 3 below.
Table 1 design parameters of optical lens 10
Figure BDA0002343464480000121
Figure BDA0002343464480000131
Wherein S is1Denotes the object side surface, S, of the first lens 1112Representing the image side surface, S, of the first lens 1113Denotes the object side surface, S, of the second lens 1124Showing the image side of the second mirror 112, STO the diaphragm 12, S5Denotes the object side surface, S, of the third lens 1136Denotes the image side surface, S, of the third mirror 1137Denotes the object side surface, S, of the fourth lens 1148Denotes the image side surface, S, of the fourth lens element 1149Denotes the object side surface, S, of the fifth lens element 11510Represents the image side surface, S, of the fifth lens element 11511Denotes the object side surface, S, of the sixth lens element 11612Denotes the image side surface, S, of the sixth lens element 11613Denotes the object side, S, of the optical filter 3014Showing the image side surface of optical filter 30. In the present application, S is1、S2、S3、S4、STO、S5、S6、S7、S8、S9、S10、S11、S12、S13、S14The same notations have the same meanings, and are not described in detail when appearing again later.
Table 2 design parameters of the optical lens 10
Figure BDA0002343464480000132
Figure BDA0002343464480000141
Wherein K represents the conic coefficient, alpha1、α2、α3、α4、α5、α6、α7、α8、α9、α10、α11、α12、α13、α14、α15、α16The equal sign represents the polynomial coefficient.
A formula satisfied by substituting the above parameters into a rotationally symmetric free-form surface:
Figure BDA0002343464480000142
namely, the first lens 111, the second lens 112, the third lens 113, the fourth lens 114 and the fifth lens 115 can be designed.
Table 3 design parameters of the optical lens 10
Parameter(s) S11 S12
K -1.0181 -7.9092
A1 6.6144 0.1746
A2 6.5810 0.1039
A3 -3.4192 -0.5776
A4 -1.6785 -0.0347
A5 -1.7459 -0.2677
A6 0.4120 -0.1045
A7 0.4520 0.0886
A8 1.5625 0.3330
A9 1.5491 0.3683
A10 0.3978 0.0766
A11 -0.9257 -0.2685
A12 0.0178 -0.1608
A13 -0.1031 -0.1197
A14 0.0388 -0.0184
A formula satisfied by substituting the above parameters into a non-rotationally symmetric free-form surface:
Figure BDA0002343464480000143
Figure BDA0002343464480000151
i.e., the sixth lens 116 can be designed.
The optical lens 10 designed according to the above parameters has the basic parameters shown in table 4.
Table 4 basic parameters of the optical lens 10
Focal length f 3.05mm
F value of aperture 2.2
FOV 120°
Total optical length TTL 5.564mm
First direction optical distortion -9.5％
Optical distortion in the second direction -4.5％
First direction TV distortion 0.2％
Second direction TV distortion 0.1％
In the embodiment of the present application, the focal length of the optical lens 10 is 3.05mm, the total optical length TTL is 5.564mm, and the ImgH is 5.186mm, that is, TTL/ImgH is less than or equal to 1.50 in the embodiment. When TTL/ImgH is less than or equal to 1.50, a high imaging pixel can be obtained, and the total lens group length TTL of the optical lens 10 is small, so that the optical lens 10 is conveniently applied to terminal devices such as mobile phones, and the terminal devices such as mobile phones are thinned. The FOV of the optical lens 10 is 120 °, that is, the optical lens 10 of the present embodiment is a wide-angle lens. The optical distortion of the optical lens 10 in the first direction and the optical distortion of the optical lens in the second direction are both greater than 3%, that is, the contraction distortion of the three-dimensional scene edge object in the first direction and the contraction distortion of the three-dimensional scene edge object in the second direction, which are generated by imaging after the three-dimensional scene edge object passes through the optical lens 10, can both be greater than 3%, so that a good correction effect is generated on the stretching distortion generated by imaging of the three-dimensional scene edge object, and a good imaging quality is obtained. The TV distortion of the optical lens 100 is less than 1%, so that the obtained image is guaranteed to have no obvious bending deformation at the edge after being corrected, and better imaging quality is obtained. It should be noted that the present application only shows one embodiment of the optical lens 10, but the present application also discloses another embodiment of the optical lens 10 to correct the stretching deformation generated during the imaging of the edge object of the three-dimensional scene, so as to obtain a better imaging.
In the present application, at least one non-rotational symmetric lens is disposed in the lens 11 of the optical lens 10 for imaging, the non-rotational symmetric lens can adjust the symmetric relationship of the lens imaging surface, and the symmetric relationship of the lens rotational symmetry from the center is changed into a symmetric relationship of two-axis symmetry, so that the optical lens 10 generates the contraction distortion along the first direction and/or the contraction distortion along the second direction when imaging the three-dimensional scene edge object, and the optical lens 10 can correct the stretching deformation generated when imaging the three-dimensional scene edge object exactly by the contraction distortion along the first direction and/or the contraction distortion along the second direction generated by imaging, thereby obtaining better imaging. Meanwhile, the deformation along the two directions can keep the straight line in the image horizontal and vertical and still keep the straight line, so that the contraction distortion is not easy to be found, and better imaging is obtained.
The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present application, and shall be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims (15)

1. An optical lens is characterized by comprising a plurality of lenses arranged from an object side to an image side, wherein the plurality of lenses comprises at least one non-rotation symmetrical lens, the non-rotation symmetrical lens is used for adjusting the symmetry characteristic of an imaging area of the optical lens to be two-axis symmetry, so that the imaging of a three-dimensional scene through the optical lens generates contraction distortion in a first direction and/or contraction distortion in a second direction, and the first direction is perpendicular to the second direction.
2. An optical lens according to claim 1, wherein the non-rotationally symmetric optic comprises an object side surface and an image side surface, the object side surface and/or the image side surface being a non-rotationally symmetric surface that satisfies the formula:
Figure FDA0002343464470000011
wherein z is the optical surface rise; r is the height of radius in the direction of the optical axis, wherein r2＝x2+y2(ii) a c is the radius of curvature; k is the cone coefficient; a. theiIs a polynomial coefficient; eiIs a power series in the x and y directions;
Figure FDA0002343464470000012
3. an optical lens according to claim 1 or 2, characterized in that the non-rotationally symmetric optic has two planes of symmetry, one of which is parallel to the first direction and the other of which is parallel to the second direction.
4. An optical lens as claimed in claim 1, characterized in that the non-rotationally symmetric lens is close to the image side of the optical lens with respect to the other lenses.
5. An optical lens according to claim 1, wherein the optical lens gradually increases the amount of deformation of the image that causes the shrinkage distortion in the first direction from the middle deformation position to the edge of the imaging field of view, and the optical lens gradually increases the amount of deformation of the image that causes the shrinkage distortion in the second direction from the middle deformation position to the edge of the imaging field of view.
6. An optical lens according to claim 1 or 5, wherein the optical lens makes deformation amounts of contraction distortion that images are caused to be at the same position in the first direction and at different positions in the second direction the same; the optical lens makes deformation amounts of contraction distortion of the image generated at the same position in the second direction and different positions in the first direction the same.
7. An optical lens according to claim 1, wherein the optical lens causes no less than 3% optical distortion in the first direction and/or in the second direction resulting from imaging.
8. An optical lens as claimed in claim 1 or 7, characterized in that the optical lens causes no more than 1% of the TV distortion in the first direction and/or in the second direction resulting from the imaging.
9. The optical lens assembly as claimed in claim 1, wherein an image plane distance corresponding to infinity from an object side surface of the first lens element to the object is a lens group system total length TTL, and a diagonal half length of an effective pixel area of an imaging plane of the lens group is ImgH, satisfying a condition: TTL/ImgH is less than or equal to 1.50.
10. An optical lens according to claim 1, characterized in that the focal length of the optical lens is less than 20 mm.
11. An optical lens according to claim 1, characterized in that the maximum field angle of the optical lens exceeds 100 °.
12. An optical lens according to claim 1, wherein the other lenses except the non-rotationally symmetric lens are rotationally symmetric lenses, and the object side surface and/or the lateral side surface of the rotationally symmetric lens are rotationally symmetric free-form surfaces, and the rotationally symmetric free-form surfaces satisfy the following formula:
Figure FDA0002343464470000021
wherein y is the rise of the aspheric surface, r is the radial coordinate of the aspheric surface, c is the vertex curvature of the aspheric surface, K is the conic constant, aiIs the aspheric coefficient and ρ is the normalized axial coordinate.
13. A camera module, comprising a photosensitive element and the optical lens of any one of claims 1 to 12, wherein the photosensitive element is located on the image side of the optical lens, and light passes through the optical lens and then is projected onto the photosensitive element.
14. The camera module according to claim 13, wherein the photosensitive element has a square shape, the photosensitive element includes a first side and a second side perpendicular to each other, the first direction is the same as the extending direction of the first side, and the second direction is the same as the extending direction of the second side.
15. A terminal comprising an image processor and a camera module according to claim 13 or 14, said image processor being in communication with said camera module, said camera module being configured to acquire image data and input said image data into said image processor, said image processor being configured to process said image data output therefrom.
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