CN112505809A

CN112505809A - Focusing device, optical imaging system, image capturing module and electronic device

Info

Publication number: CN112505809A
Application number: CN202011384941.1A
Authority: CN
Inventors: 邹金华; 刘彬彬; 李明
Original assignee: Jiangxi Jingchao Optical Co Ltd
Current assignee: Jiangxi Jingchao Optical Co Ltd
Priority date: 2020-11-30
Filing date: 2020-11-30
Publication date: 2021-03-16

Abstract

The invention provides a focusing device, an optical imaging system, an image capturing module and an electronic device, wherein the focusing device comprises a light guide layer and an electric deformation layer from an object side to an image side along an optical axis, the image side surface of the light guide layer is flexible, the object side surface of the electric deformation layer is glued with the image side surface of the light guide layer, and the electric deformation layer deforms after being electrified and drives the image side surface of the light guide layer to deform. The focusing device, the optical imaging system, the image capturing module and the electronic device avoid a complex calibration process and reduce the automatic focusing response time.

Description

Focusing device, optical imaging system, image capturing module and electronic device

Technical Field

The present disclosure relates to optical imaging technologies, and particularly to a focusing device, an optical imaging system, an image capturing module and an electronic device.

Background

Currently, lens focusing modes are classified into manual focusing and auto focusing. Manual focusing requires manual adjustment of the focusing ring, and therefore shooting efficiency is low and operation requirements on a user are high. The camera focusing system can always carry out follow focusing by the selected focusing point in a linked mode, the shooting efficiency is high, and the operation is convenient.

The existing automatic focusing adopts a Voice Coil Motor (VCM) technology, namely, a physical focusing mode with a clear imaging surface is realized by moving the whole lens group through a focusing screw thread.

In the process of implementing the present application, the inventor finds that at least the following problems exist in the prior art: the existing voice coil motor technology is influenced by temperature and mechanical vibration, needs a complex calibration process and has long automatic focusing response time.

Disclosure of Invention

In view of the foregoing, it is desirable to provide a focusing apparatus, an optical imaging system, an image capturing module and an electronic apparatus to solve the above problems.

The embodiment of the application provides a focusing device, focusing device is followed the optical axis and is included leaded light layer and electrical deformation layer by thing side to image side, the image side on leaded light layer has the flexibility, the thing side on electrical deformation layer with the image side veneer on leaded light layer, produce deformation and drive after the electrical deformation layer circular telegram the image side on leaded light layer takes place deformation.

In the focusing device, the object side surface of the electro-deformation layer is glued with the image side surface of the light guide layer, the electro-deformation layer is deformed after being electrified and drives the image side surface of the light guide layer to be deformed, so that the curvature radius of the image side surface of the light guide layer is changed along with the curvature radius of the object side surface of the electro-deformation layer, and further the function of optical focusing is realized. The object side surface of the electro-deformation layer is tightly attached to the image side surface of the light guide layer in a gluing mode, and gaps or falling off are avoided. Compared with the traditional lens automatic focusing mode, namely the physical focusing mode with clear imaging surface is realized by moving the whole lens group through the focusing screw threads, the electro-deformation layer is not influenced by temperature and does not generate mechanical vibration, the complicated calibration process is avoided, and the automatic focusing response time is shortened.

In some embodiments, the light guiding layer is made of a flexible polymer and the electro-deformable layer is made of a piezoelectric material.

So, the leaded light layer is made by flexible polymer, so that the image side on leaded light layer has the flexibility, and then makes the image side on leaded light layer with the thing side gluing on electrostrictive layer is passed through the electrostrictive layer produces deformation and drives the image side on leaded light layer takes place deformation, realizes the function of optics focusing. The electro-deformation layer is made of a piezoelectric material, the piezoelectric material has an inverse piezoelectric effect, namely, an electric field is applied to the piezoelectric material, the piezoelectric material generates mechanical deformation, when an external electric field is removed, the piezoelectric film generates mechanical deformation and disappears, the electro-deformation layer is electrified through the inverse piezoelectric effect, the electro-deformation layer is stressed and deformed, the curvature radius of the object side and the image side of the electro-deformation layer is changed, and the optical focusing function is realized. Compared with a thread focusing mode, the electro-deformation layer is not influenced by temperature, mechanical vibration cannot be generated, a complex calibration process is avoided, and the automatic focusing response time is shortened.

In some embodiments, the light guide layer is a liquid-filled lens, the light guide layer is filled with a liquid, and the liquid in the light guide layer is pressurized by the electro-deformable layer, so that the liquid is redistributed in the cavity of the light guide layer, and the curvature of the surface of the light guide layer changes.

Therefore, the liquid filling type lens transmission medium is liquid, pressure is applied to the liquid through the electric deformation layer, resistance of the light guide layer to the electric deformation layer is weakened, and power consumption required by deformation of the electric deformation layer is reduced. And the focal length is changed by changing the surface shape of the light guide layer through the liquid, and the liquid zoom lens has the advantages of flexible aperture size, large zoom range and small occupied volume.

In some embodiments, the focusing device further comprises a protective layer, the light guide layer and the electro-deformable layer are sequentially attached to each other, and the thickness of the electro-deformable layer ranges from 0.02mm to 0.1 mm.

Therefore, the object side of the light guide layer is attached to the protective layer, the image side of the light guide layer is attached to the object side of the electro-deformation layer, the curvature radius of the object side of the electro-deformation layer is adjusted by electrifying the electro-deformation layer, and the curvature radius of the image side of the light guide layer is driven to change together, so that light deflection is changed, and further the function of optical focusing is realized. When satisfying the focusing function, the thickness scope of electrostriction layer is 0.02mm to 0.1mm, compares with traditional mechanical mode of zooming, and optical imaging system size is littleer, and the motion trail is shorter, effectively reduces the thickness of using optical imaging system device, and then is favorable to optical imaging system miniaturization.

In some embodiments, the object side of the electro-deformable layer has a radius of curvature at the optical axis of R1, R1 satisfying the following relationship: -500mm < R1 < 500 mm; the radius of curvature of the image side surface of the electro-deformable layer at the optical axis is R2, and R2 satisfies the following relation: -500mm < R2 < 500 mm.

Thus, R₁And R₂The smaller the numerical value of (2), the larger the curvature, correspondingly, the larger the curvature, the closer the shooting distance becomes, so that the close-distance shooting can be realized by matching with the lens assembly, and the larger the curvature, the smaller the light deflection degree is, and the more concentrated the light rays come out from the electrostrictive layer, so that the imaging is clear.

In some embodiments, the thickness of the focusing device on the optical axis ranges from 0.510mm to 0.580 mm.

So, when satisfying the focusing function, focusing device is 0.510mm to 0.580mm in the epaxial thickness scope of optical, compares with the mode that traditional machinery zoomed, and optical imaging system size is littleer, and the motion trail is shorter, effectively reduces the thickness of using optical imaging system device, and then is favorable to optical imaging system miniaturization.

An embodiment of the present invention provides an optical imaging system, including the focusing apparatus in the foregoing embodiment, and further including a lens assembly, where the focusing apparatus is disposed on an object side of the lens assembly or in the lens assembly.

In the above optical imaging system, the lens assembly is used for imaging, and the lens assembly is matched with the focusing device to realize optical focusing, so that the whole imaging surface is clear and uniform. The electro-deformable layer in the optical imaging system is not affected by temperature and does not generate mechanical shock, thereby avoiding complex calibration process and reducing auto-focusing response time.

In some embodiments, the lens assembly comprises, from an object side to an image side: a first lens element with refractive power having a convex object-side surface at paraxial region; a second lens element with refractive power; a third lens element with refractive power; a fourth lens element with refractive power having a concave object-side surface at a paraxial region and a concave image-side surface at a paraxial region.

Therefore, through reasonable refractive power configuration and surface type arrangement, the sensitivity of the lens assembly to the object distance change is improved.

In some embodiments, the focusing apparatus is disposed on an object side of the first lens or between the second lens and a third lens.

Therefore, under the condition that the shot object distance is changed, the focusing function of the lens and the contrast of imaging analysis force are realized by adjusting the curvature radius value of the electrostriction layer.

An embodiment of the present invention provides an image capturing module, which includes a photosensitive element and the optical imaging system described in the above embodiment, wherein the photosensitive element is disposed at an image side of the optical imaging system.

The image capturing module comprises an optical imaging system, the optical imaging system has the advantages of miniaturization, simpler process and clearer and more uniform focusing imaging picture, the thickness of the image capturing module can be reduced on the premise of ensuring the high imaging quality of the optical imaging system, and the underscreen packaging of the optical imaging system is facilitated. The electro-deformation layer in the image capturing module is not affected by temperature, mechanical vibration is not generated, a complex calibration process is avoided, and the automatic focusing response time is shortened.

The embodiment of the invention provides an electronic device, which comprises a shell and the image capturing module of the embodiment, wherein the image capturing module is installed on the shell.

The optical imaging system in the electronic device of the embodiment of the invention has the advantages of miniaturization, simpler process and clearer and more uniform focusing imaging picture. On one hand, the thickness of the electronic device can be reduced on the premise of ensuring the high imaging quality of the optical imaging system, so that the electronic device is favorable for achieving the light and thin effect; on the other hand, in the shooting effect, the function of lens focusing and the contrast of imaging analysis force are realized by the optical imaging system through adjusting the curvature radius value of the electrostrictive layer, so that clearer imaging is obtained, and the shooting experience of a user is met. The electro-deformable layer in the electronic device is not affected by temperature and does not generate mechanical shock, thereby avoiding complex calibration process and reducing auto-focusing response time.

Drawings

Fig. 1 is a schematic structural diagram of a focusing apparatus according to an embodiment of the present invention.

Fig. 2 is a schematic structural diagram of an optical imaging system in which a focusing apparatus according to an embodiment of the present invention is disposed on an object side of a lens assembly.

Fig. 3 is a schematic structural diagram of an optical imaging system in which a focusing apparatus is disposed in a lens assembly according to an embodiment of the present invention.

Fig. 4 is a schematic structural diagram of an image capturing module according to an embodiment of the invention.

Fig. 5 is a schematic structural diagram of an electronic device according to an embodiment of the invention.

Fig. 6 is an MTF graph of an optical imaging system in which a focusing apparatus according to a first embodiment of the present invention is disposed on an object side of a lens assembly.

Fig. 7 is an MTF graph of an optical imaging system before focusing by changing an object distance of the optical imaging system by-0.04 mm when a focusing apparatus of the first embodiment of the present invention is disposed on the object side of the lens assembly.

Fig. 8 is an MTF graph of an optical imaging system after changing an object distance of the optical imaging system by-0.04 mm and focusing, wherein the focusing apparatus is disposed on the object side of the lens assembly according to the first embodiment of the present invention.

Fig. 9 is an MTF graph of an optical imaging system before focusing by changing an object distance of the optical imaging system by-0.1 mm when the focusing apparatus of the first embodiment of the present invention is disposed on the object side of the lens assembly.

Fig. 10 is an MTF graph of an optical imaging system after changing an object distance of the optical imaging system by-0.1 mm and focusing the focusing apparatus on the object side of the lens assembly according to the first embodiment of the present invention.

Fig. 11 is an MTF graph of an optical imaging system before focusing by changing an object distance of the optical imaging system by-0.2 mm when the focusing apparatus of the first embodiment of the present invention is disposed on the object side of the lens assembly.

Fig. 12 is an MTF graph of an optical imaging system after changing an object distance of the optical imaging system by-0.2 mm and focusing, wherein the focusing apparatus is disposed on the object side of the lens assembly according to the first embodiment of the present invention.

Fig. 13 is a graph of MTF of an optical imaging system in which a focusing apparatus according to a first embodiment of the present invention is disposed in a lens assembly.

Fig. 14 is a graph of MTF of an optical imaging system before focusing by changing the object distance of the optical imaging system by +0.04mm in which the focusing apparatus according to the first embodiment of the present invention is disposed in the lens assembly.

Fig. 15 is a graph of MTF of the optical imaging system after focusing by changing the object distance of the optical imaging system by +0.04mm, wherein the focusing apparatus of the first embodiment of the invention is disposed in the lens assembly.

Fig. 16 is a graph of MTF of an optical imaging system before focusing, with a focusing apparatus according to a first embodiment of the present invention disposed in a lens assembly, for an object distance change of +0.1 mm.

Fig. 17 is a graph of MTF of the optical imaging system of the first embodiment of the present invention, after focusing, with the object distance of the optical imaging system changed by +0.1 mm.

Fig. 18 is a graph of MTF of an optical imaging system before focusing, with a focusing apparatus according to a first embodiment of the present invention disposed in a lens assembly, for an object distance change of +0.2 mm.

Fig. 19 is a graph of MTF of the optical imaging system of the first embodiment of the present invention when the focusing apparatus is disposed in the lens assembly after focusing the lens assembly with an object distance change of +0.2 mm.

Description of the main elements

Optical imaging system 100

Focusing device 10

Protective layer 12

Light guiding layer 14

The electro-deformable layer 16

Lens assembly 20

First lens L1

Second lens L2

Third lens L3

Fourth lens L4

Infrared filter L5

Object sides S1, S3, S5, S7, S9, S11, S13

Like sides S2, S4, S6, S8, S10, S12, S14

Image plane S15

Photosensitive element 30

Housing 40

Image capturing module 1000

Electronic device 10000

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like, indicate orientations and positional relationships based on those shown in the drawings, and are used only for convenience of description and simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be considered as limiting the present invention. Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", may explicitly or implicitly include one or more of the described features. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; may be mechanically connected, may be electrically connected or may be in communication with each other; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly above and obliquely above the second feature, or simply meaning that the first feature is at a lesser level than the second feature.

The following disclosure provides many different embodiments or examples for implementing different features of the invention. To simplify the disclosure of the present invention, the components and arrangements of specific examples are described below. Of course, they are merely examples and are not intended to limit the present invention. Furthermore, the present invention may repeat reference numerals and/or letters in the various examples, such repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. In addition, the present invention provides examples of various specific processes and materials, but one of ordinary skill in the art may recognize applications of other processes and/or uses of other materials.

Referring to fig. 1, a focusing apparatus 10 according to an embodiment of the present invention includes a protection layer 12, a light guiding layer 14, and an electro-deformable layer 16 in order from an object side to an image side along an optical axis. Protective layer 12, leaded light layer 14 and the laminating in proper order of electrical deformation layer 16, protective layer 12 are used for protecting focusing device 10, and leaded light layer 14 is used for propagating light, changes the light deflection through the curvature radius who adjusts electrical deformation layer 16, and then realizes the function of optics focusing.

Specifically, the light guiding layer 14 has an object side S11 and an image side S12, and the electro-deformable layer 16 has an object side S13 and an image side S14. The object side surface S11 of the light guide layer 14 is attached to the protective layer 12. The image side S12 of the light guiding layer 14 is attached to the object side S13 of the electro-deformable layer 16. By electrically adjusting the curvature radius of the object-side surface S13 of the electro-deformable layer 16 and driving the curvature radius of the image-side surface S12 of the light guide layer 14 to change together, the absolute value of the curvature radius of the object-side surface S13 of the electro-deformable layer 16 is equal to the absolute value of the curvature radius of the image-side surface S12 of the light guide layer 14, so as to change the light deflection and further realize the function of optical focusing.

In some embodiments, the protective layer 12 is made of a glass material, in which case the focusing apparatus 10 can withstand higher temperatures and have better optical performance.

The image side S12 of the light guide layer 14 is flexible, the object side S13 of the electro-deformable layer 16 is glued to the image side S12 of the light guide layer 14, and the electro-deformable layer 16 deforms when energized and drives the image side S12 of the light guide layer 14 to deform. The object side surface S13 of the electro-deformable layer 16 and the image side surface S12 of the light guide layer 14 are tightly attached to each other by gluing, so that gaps or falling off are avoided.

In some embodiments, the light guiding layer 14 is made of a polymer material to have flexibility and easy deformation characteristics, so that the object side surface S11 of the light guiding layer 14 is attached to the protection layer 12, the image side surface S12 of the light guiding layer 14 is attached to the object side surface S13 of the electro-deformable layer 16, and the curvature radius of the image side surface S12 of the light guiding layer 14 is changed along with the curvature radius of the object side surface S13 of the electro-deformable layer 16. In some embodiments, the light guide layer 14 is made of PDMS (polydimethylsiloxane) material, has excellent light transmittance, electrical insulation, weather resistance, hydrophobicity, and high shear resistance, and facilitates improving structural stability of the light guide layer 14.

It is understood that in other embodiments, the light guiding layer 14 is a liquid-filled lens, the light guiding layer 14 is filled with a liquid, and the liquid in the light guiding layer 14 is pressurized by the electro-deformable layer 16, so that the liquid is redistributed within the cavity of the light guiding layer 14, resulting in a change in the curvature of the surface of the light guiding layer 14. The application of pressure to the liquid by the electro-deformable layer 16 reduces the resistance of the light guiding layer 14 to the electro-deformable layer 16, thereby reducing the power consumption required to deform the electro-deformable layer 16. Moreover, the liquid filling type lens transmission medium is liquid, the focal length is changed by changing the surface shape of the light guide layer 14 through the liquid, and the liquid filling type lens has the advantages of flexible aperture size, large zooming range and small occupied volume.

The electrostrictive layer 16 is a piezoelectric film, and the piezoelectric film has an inverse piezoelectric effect, that is, an alternating electric field is applied to the piezoelectric film, the piezoelectric film generates mechanical deformation, and when the external electric field is removed, the mechanical deformation generated by the piezoelectric film disappears. Specifically, by electrifying the electro-deformable layer 16, the electro-deformable layer 16 is deformed by inverse piezoelectric effect, so that the curvature radius of the object-side surface S13 and the image-side surface S14 of the electro-deformable layer 16 is changed, the deformed electro-deformable layer 16 drives the image-side surface S12 of the light guide layer 14 to deform together, so that the curvature radius of the image-side surface S12 of the light guide layer 14 is changed together with the curvature radius of the object-side surface S13 of the electro-deformable layer 16, and the function of optical focusing is realized. In some embodiments, the electro-deformable layer 16 is made of PZT (lead zirconate titanate piezoelectric ceramic) material, which has the advantages of more stable performance and higher piezoelectric constant, and facilitates improved stability of the adjustment of the electro-deformable layer 16.

It will be appreciated that in other embodiments, the electro-deformable layer 16 is made of one or more of a single crystal, a polycrystalline, and an organic piezoelectric material. The single crystal can be one or more of quartz, water-soluble piezoelectric crystal and lithium niobate crystal; the polycrystal can be one or more of barium titanate piezoelectric ceramics, niobate piezoelectric ceramics and lead magnesium niobate piezoelectric ceramics; the organic piezoelectric material may be piezoelectric rubber or plastic, etc.

In some embodiments, the electro-deformable layer 16 has a thickness in the range of 0.02mm to 0.1mm, such as values of 0.02mm, 0.03mm, 0.04mm, 0.05mm, 0.06mm, 0.07mm, 0.08mm, 0.09mm, 0.1mm, and the like; the thickness of the focusing apparatus 10 ranges from 0.510mm to 0.580mm, for example, 0.510mm, 0.520mm, 0.530mm, 0.540mm, 0.550mm, 0.560mm, 0.570mm, 0.580mm, etc. The thickness of the electrostrictive layer 16 and the thickness range of the focusing device 10 are controlled, so that the size of the optical imaging system 100 is smaller, the motion track is shorter, the thickness of the device applying the optical imaging system 100 is effectively reduced, and the miniaturization of the optical imaging system 100 is facilitated.

In some embodiments, the object side S13 of the electro-deformable layer 16 has a radius of curvature R₁，R₁The following relation is satisfied: -500mm < R₁Less than 500 mm; the image-side surface S14 of the electro-deformable layer 16 has a radius of curvature R₂，R₂The following relation is satisfied: -500mm < R₂＜500mm。R₁And R₂The smaller the value of (b), the larger the curvature. Accordingly, the greater the curvature, the closer the distance of the photographing becomes, facilitating the close-distance photographing in cooperation with the lens assembly 20. And the greater the curvature the less the light is deflected and the more concentrated the light emerges from the electro-deformable layer 16 for clear imaging.

Referring to fig. 2 and fig. 3 together, an optical imaging system 100 according to an embodiment of the present invention includes the focusing device 10 and the lens assembly 20, where the focusing device 10 is used for adjusting a focal length, and the lens assembly 20 is used for imaging. The focusing device 10 is disposed in the object side direction of the lens assembly 20 or disposed in the lens assembly 20 to achieve optical focusing, so that the whole image plane is clear and uniform.

The lens assembly 20 includes, in order from an object side to an image side: a first lens element L1 with refractive power; a second lens element L2 with refractive power; a third lens element L3 with refractive power; and a fourth lens element L4 with refractive power.

The first lens element L1 has an object-side surface S1 and an image-side surface S2, the object-side surface S1 being convex at the paraxial region, and the image-side surface S2 being convex at the paraxial region; the second lens element L2 has an object-side surface S3 and an image-side surface S4, the object-side surface S3 being concave at the paraxial region; the third lens element L3 has an object-side surface S5 and an image-side surface S6, the object-side surface S5 being concave at the paraxial region and the image-side surface S6 being convex at the paraxial region; the fourth lens element L4 has an object-side surface S7 and an image-side surface S8, the object-side surface S7 being concave at the paraxial region, and the image-side surface S8 being concave at the paraxial region. In addition, the image side of the lens assembly 20 has an image plane S15, and preferably, the image plane S15 may be a receiving surface of the photosensitive element.

In some embodiments, the lens assembly 20 further includes an infrared filter L5, the infrared filter L5 having an object side S9 and an image side S10. The infrared filter L5 is disposed on the image side S8 of the fourth lens L4, and the infrared filter L5 is used for filtering the light of the image, specifically isolating the infrared light, and preventing the infrared light from being received by the photosensitive element, so as to prevent the infrared light from affecting the color and the definition of the normal image, and further improve the imaging quality of the optical imaging system 100.

In some embodiments, the first lens L1, the second lens L2, the third lens L3 and the fourth lens L4 are all made of plastic, and the plastic lens can reduce the weight and the production cost of the lens assembly 20, and further reduce the weight and the production cost of the optical imaging system 100.

In some embodiments, the first lens L1, the second lens L2, the third lens L3 and the fourth lens L4 are made of glass, so that the lens assembly 20 can endure higher temperature and has better optical performance.

In other embodiments, only the first lens L1 may be made of glass, and the other lenses may be made of plastic, in which case, the first lens L1 closest to the object side can better withstand the influence of the ambient temperature on the object side, and the production cost of the optical imaging system 100 is kept low because the other lenses are made of plastic. Alternatively, in some embodiments, the material of the first lens L1 is glass, and the materials of the other lenses can be combined arbitrarily. In this way, the optical imaging system 100 can realize ultra-thinning while correcting aberration and solving the temperature drift problem by reasonable configuration of the material of the lens, and the cost is low.

The lens assembly 20 is sensitive to object distance changes through reasonable refractive power configuration and surface type setting, is suitable for macro photography, and can more intuitively express focusing and imaging modes of the optical imaging system 100. It is understood that the lens assembly 20 is not limited to the arrangement of four-piece lenses in the present embodiment, and may also be other number of lens combinations, such as one-piece, two-piece, three-piece, and multi-piece; in addition, the arrangement and the face-type arrangement of the refractive power in the lens assembly 20 may be other ways.

Referring to fig. 2, in some embodiments, the focusing apparatus 10 is disposed on the object side of the lens assembly 20, and specifically, the focusing apparatus 10 is disposed on the object side of the first lens L1. At this time, when the optical imaging system 100 is used for imaging, light emitted or reflected by a subject enters the optical imaging system 100 from the object side direction, and passes through the protective layer 12, the light guide layer 14, the electrostrictive layer 16, the first lens L1, the second lens L2, the third lens L3, and the fourth lens L4 in sequence, and finally converges on the image plane S15. Under the condition that the shooting object distance is changed, the focusing function of the lens and the contrast of imaging analysis force are realized by adjusting the curvature radius value of the electrostriction layer 16.

Referring to fig. 2, in some embodiments, the focusing apparatus 10 is disposed in the lens assembly 20, and specifically, the focusing apparatus 10 is disposed between the second lens L2 and the third lens L3. At this time, when the optical imaging system 100 is used for imaging, light rays emitted or reflected by a subject enter the optical imaging system 100 from the object side direction, sequentially pass through the first lens L1, the second lens L2, the protective layer 12, the light guiding layer 14, the electro-deformable layer 16, the third lens L3, and the fourth lens L4, and finally converge on the image plane S15. Under the condition that the shooting object distance is changed, the focusing function of the lens and the contrast of imaging analysis force are realized by adjusting the curvature radius value of the electrostriction layer 16.

In some embodiments, the optical imaging system 100 further includes an aperture disposed between the focusing apparatus 10 and the lens assembly 20 when the focusing apparatus 10 is disposed in the object-side direction of the lens assembly 20, specifically, between the image-side surface of the electro-deformable layer 16 and the object-side surface of the first lens L1. The diaphragm is used for reducing stray light, and the image quality is improved. When the focusing apparatus 10 is disposed in the lens assembly 20, a diaphragm is disposed in the object side direction of the lens assembly 20, specifically, the diaphragm is disposed in the object side direction of the first lens L1. At this time, the position of the diaphragm in the whole optical imaging system 100 is relatively forward, so that the optical imaging system 100 has a telecentric effect, and the efficiency of receiving the image by the photosensitive element 30 can be increased, thereby improving the imaging quality.

In the above-mentioned optical imaging system 100, compare traditional camera lens automatic focusing mode, move whole lens group through the focusing thread promptly and realize the clear physics mode of focusing of image plane, have following advantage:

1. the automatic focusing response is quick, and the response time is less than 1 ms;

2. the continuous clear imaging can be kept in the photographing and image capturing processes, and the fuzzy state cannot occur in the focusing process;

3. the optical system has higher stability of an optical axis, is not influenced by temperature and mechanical vibration, does not need a complex calibration process, and can simplify processing and manufacturing to have better imaging quality;

4. the power consumption is extremely low, the power consumption is less than 1mW, the micro-camera and the wearable device can be applied, and the low power consumption can not generate overhigh temperature and influence the imaging quality of the photosensitive chip;

5. the optical imaging system 100 has smaller size and shorter motion track, effectively reduces the thickness of the photographing and image-taking module, and is further beneficial to the miniaturization of the optical imaging system 100.

Referring to fig. 4, an image capturing module 1000 according to an embodiment of the present invention includes an optical imaging system 100 and a photosensitive element 30, wherein the photosensitive element 30 is disposed at an image side of the optical imaging system 100. Specifically, the photosensitive element 30 may be a Complementary Metal Oxide Semiconductor (CMOS) image sensor or a Charge-coupled Device (CCD).

The image capturing module 1000 of the embodiment of the invention comprises the optical imaging system 100, and the optical imaging system 100 has the advantages of miniaturization, simpler process and clearer and more uniform focusing imaging picture. The thickness of the image capturing module 1000 can be reduced on the premise of ensuring the high imaging quality of the optical imaging system 100, and the under-screen packaging of the image capturing module 1000 is facilitated.

Referring to fig. 5, an electronic device 10000 according to an embodiment of the invention includes a housing 40 and an image capturing module 1000, wherein the image capturing module 1000 is mounted on the housing 40 for capturing an image.

The electronic device 10000 according to the embodiment of the present invention includes, but is not limited to, an electronic device supporting imaging, such as a smart phone, an automotive lens, a monitoring lens, a tablet computer, a notebook computer, an electronic book reader, a Portable Multimedia Player (PMP), a portable phone, a video phone, a digital still camera, a mobile medical device, and a wearable device.

The optical imaging system 100 in the electronic device 10000 of the above embodiment has the advantages of miniaturization, simpler process and clearer and more uniform focusing imaging picture. On one hand, the thickness of the electronic device 10000 can be reduced on the premise of ensuring the high imaging quality of the optical imaging system 100, so that the electronic device can achieve a light and thin effect; on the other hand, in terms of the shooting effect, the optical imaging system 100 realizes the function of lens focusing and the contrast of imaging resolution by adjusting the curvature radius value of the electrostrictive layer 16, so that clearer imaging is obtained, and the shooting experience of a user is met.

The invention is illustrated by the following specific embodiments:

first embodiment

Referring to fig. 2 and fig. 6, the optical imaging system 100 of the first embodiment includes, in order from an object side to an image side, a cover glass, a protective layer 12, a light guiding layer 14, an electro-deformable layer 16, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, and an infrared filter L5.

The object-side surface S1 of the first lens element L1 is convex at the paraxial region, and the image-side surface S2 is convex at the paraxial region; the object-side surface S3 of the second lens L2 is concave at the paraxial region; the object-side surface S5 of the third lens element L3 is concave at the paraxial region, and the image-side surface S6 is convex at the paraxial region; the object-side surface S7 of the fourth lens element L4 is concave at the paraxial region, and the image-side surface S8 is concave at the paraxial region.

The object side surface and the image side surface of the protective layer 12, the light guide layer 14, the electro-deformable layer 16 are all spherical surfaces.

The material of the protection layer 12 is glass. The light guiding layer 14 is made of polymer.

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

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

The reference wavelength in the first embodiment is 587.6nm, and the optical imaging system 100 in the first embodiment satisfies the conditions of the following table. The elements from the object plane to the image plane are sequentially arranged in the order of the elements from top to bottom in table 1. The surface number 1 and the surface number 2 are respectively an object side surface and an image side surface of the cover plate glass; the surface number 3 is a protective layer; the surface number 4 is a light guide layer; surface number 5 and surface number 6 are the object side and image side of the electro-deformable layer, respectively; surface numbers 8 and 9 are the object-side surface S1 and the image-side surface S2 of the first lens L1, respectively, that is, the surface with the smaller surface number is the object-side surface and the surface with the larger surface number is the image-side surface in the same lens. The Y radius in table 1 is the radius of curvature of the object or image side at the paraxial region for the respective face number. The first value in the "thickness" parameter column of the first lens element is the thickness of the lens element on the optical axis, and the second value is the distance from the image-side surface of the lens element to the object-side surface of the subsequent lens element on the optical axis. Table 2 is a table of relevant parameters of the aspherical surface of each lens in table 1, where K is a conic constant and Ai is a coefficient corresponding to the i-th high-order term in the aspherical surface type formula.

In fig. 6, the ordinate represents MTF values, and the abscissa represents spatial frequencies. At positions offset from the center of the image field, the MTF values measured by the sinusoidal grating for lines along the tangential direction are different from those along the radial direction. The MTF curve produced by a line parallel to the diameter is called the sagittal curve, denoted s (sagittal), and the MTF curve produced by a line parallel to the tangent is called the meridional curve, denoted m (meridian). The solid line in fig. 6 is measured in the S direction and the dashed line is measured in the M direction. That is, the solid line represents the resolution of the optical imaging system 100 for the radial line, and the dashed line represents the resolution for the tangential line. The MTF value is greater than 0 and less than 1, and the more the MTF value is close to 1, the more excellent the performance of the lens is. In the first embodiment, as the spatial frequency of each interval increases, the imaging quality exhibits a slow decline tendency.

TABLE 1

It should be noted that EFL is the focal length of the optical imaging system 100, FNO is the f-number of the optical imaging system 100, FOV is the field angle of the optical imaging system 100, and OBJD is the distance from the object plane of the optical imaging system 100 to the object side S1 of the first lens L1, i.e., the object distance. The units of the Y radius and the focal length in the table are mm.

TABLE 2

Second embodiment

Referring to fig. 7 and 8, the optical imaging system 100 of the second embodiment includes, in order from an object side to an image side, a cover glass, a protective layer 12, a light guiding layer 14, an electro-deformable layer 16, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, and an infrared filter L5.

The reference wavelength in the second embodiment is 587.6nm, the object distance is changed by-0.04 mm, the data before and after focusing of the optical imaging system 100 are shown in tables 3 and 4, respectively, and the definitions of the parameters can be obtained from the first embodiment, which is not described herein again. The definitions of the parameters in fig. 7 and fig. 8 can be derived from the first embodiment, and are not repeated herein. In the second embodiment, before focusing, as the spatial frequency of each interval is increased, the imaging quality shows a rapid descending trend; after focusing, the imaging quality shows a slow descending trend as the spatial frequency of each interval increases. It can be seen that the imaging quality is significantly improved after focusing.

TABLE 3

It should be noted that EFL is the focal length of the optical imaging system 100, FNO is the f-number of the optical imaging system 100, FOV is the field angle of the optical imaging system 100, and OBJD is the distance from the object plane of the optical imaging system 100 to the object side surface of the first lens, i.e., the object distance. The units of the Y radius and the focal length in the table are mm.

TABLE 4

Third embodiment

Referring to fig. 9 and 10, the optical imaging system 100 of the third embodiment includes, in order from an object side to an image side, a cover glass, a protective layer 12, a light guiding layer 14, an electro-deformable layer 16, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, and an infrared filter L5.

The reference wavelength in the third embodiment is 587.6nm, the object distance is changed by-0.1 mm, the data before and after focusing of the optical imaging system 100 are shown in tables 5 and 6, respectively, and the definitions of the parameters can be obtained from the first embodiment, which is not described herein again. The definitions of the parameters in fig. 9 and fig. 10 can be derived from the first embodiment, and are not repeated herein. In the third embodiment, before focusing, as the spatial frequency of each interval increases, the imaging quality shows a rapid descending trend; after focusing, the imaging quality shows a slow descending trend as the spatial frequency of each interval increases. It can be seen that the imaging quality is significantly improved after focusing.

TABLE 5

TABLE 6

Fourth embodiment

Referring to fig. 11 and 12, the optical imaging system 100 of the fourth embodiment includes, in order from an object side to an image side, a cover glass, a protective layer 12, a light guiding layer 14, an electro-deformable layer 16, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, and an infrared filter L5.

The reference wavelength in the fourth embodiment is 587.6nm, the object distance is changed by-0.2 mm, the data before and after focusing of the optical imaging system 100 are shown in tables 7 and 8, respectively, and the definitions of the parameters may be obtained from the first embodiment, which is not described herein again. The definitions of the parameters in fig. 11 and fig. 12 can be derived from the first embodiment, and are not repeated herein. In the fourth embodiment, before focusing, as the spatial frequency of each interval increases, the imaging quality shows a rapid descending trend; after focusing, the imaging quality shows a slow descending trend as the spatial frequency of each interval increases. It can be seen that the imaging quality is significantly improved after focusing.

TABLE 7

TABLE 8

Fifth embodiment

Referring to fig. 3 and 13, the optical imaging system 100 of the fifth embodiment includes, in order from an object side to an image side, a cover glass, a first lens element L1, a second lens element L2, a protection layer 12, a light guiding layer 14, an electro-deformable layer 16, a third lens element L3, a fourth lens element L4, and an infrared filter L5.

The reference wavelength in the fifth embodiment is 587.6nm, and the optical imaging system 100 in the fifth embodiment satisfies the conditions of the following table. The elements from the object plane to the image plane S15 are sequentially arranged in the order of the elements from top to bottom in table 1. The surface number 1 and the surface number 2 are respectively an object side surface and an image side surface of the cover plate glass; surface numbers 4 and 5 are the object-side surface S1 and the image-side surface S2 of the first lens L1, respectively, that is, the surface with the smaller surface number is the object-side surface and the surface with the larger surface number is the image-side surface in the same lens. The surface number 8 is a protective layer; the surface number 9 is a light guide layer; surface number 10 and surface number 11 are the object side and image side of the electro-deformable layer, respectively. The Y radius in table 9 is the radius of curvature of the object or image side at the paraxial region for the respective face number. The first value in the "thickness" parameter column of the first lens element is the thickness of the lens element on the optical axis, and the second value is the distance from the image-side surface of the lens element to the object-side surface of the subsequent lens element on the optical axis. Table 10 is a table of relevant parameters of the aspherical surface of each lens in table 9, where K is a conic constant and Ai is a coefficient corresponding to the i-th high-order term in the aspherical surface type formula. The definitions of the parameters in fig. 13 can be derived from the first embodiment, and are not described herein again. In the fifth embodiment, as the spatial frequency of each interval increases, the imaging quality exhibits a slow decline tendency.

TABLE 9

Watch 10

Sixth embodiment

Referring to fig. 14 and fig. 15, the optical imaging system 100 of the sixth embodiment includes, in order from an object side to an image side, a cover glass, a first lens element L1, a second lens element L2, a protective layer 12, a light guiding layer 14, an electro-deformable layer 16, a third lens element L3, a fourth lens element L4, and an infrared filter L5.

The reference wavelength in the sixth embodiment is 587.6nm, the object distance is changed by +0.04mm, the data before and after focusing of the optical imaging system 100 are shown in tables 11 and 12, respectively, and the definitions of the parameters can be obtained from the fifth embodiment, which is not described herein again. The definitions of the parameters in fig. 14 and fig. 15 can be derived from the first embodiment, and are not repeated herein. In the sixth embodiment, before focusing, as the spatial frequency of each interval increases, the imaging quality shows a rapid falling trend; after focusing, the imaging quality shows a slow descending trend as the spatial frequency of each interval increases. It can be seen that the imaging quality is significantly improved after focusing.

TABLE 11

TABLE 12

Seventh embodiment

Referring to fig. 16 and 17, the optical imaging system 100 of the seventh embodiment includes, in order from an object side to an image side, a cover glass, a first lens element L1, a second lens element L2, a protection layer 12, a light guiding layer 14, an electro-deformable layer 16, a third lens element L3, a fourth lens element L4, and an infrared filter L5.

The reference wavelength in the seventh embodiment is 587.6nm, the object distance is changed by +0.1mm, the data before and after focusing of the optical imaging system 100 are shown in tables 13 and 14, respectively, and the definitions of the parameters can be obtained from the fifth embodiment, which is not described herein again. The definitions of the parameters in fig. 16 and 17 can be derived from the first embodiment, and are not repeated herein. In the seventh embodiment, before focusing, as the spatial frequency of each interval increases, the imaging quality shows a rapid falling trend; after focusing, the imaging quality shows a slow descending trend as the spatial frequency of each interval increases. It can be seen that the imaging quality is significantly improved after focusing.

Watch 13

TABLE 14

Eighth embodiment

Referring to fig. 18 and 19, the optical imaging system 100 of the eighth embodiment includes, in order from an object side to an image side, a cover glass, a first lens element L1, a second lens element L2, a protection layer 12, a light guiding layer 14, an electro-deformable layer 16, a third lens element L3, a fourth lens element L4, and an infrared filter L5.

The reference wavelength in the eighth embodiment is 587.6nm, the object distance is changed by +0.2mm, the data before and after focusing of the optical imaging system 100 are shown in tables 15 and 16, respectively, and the definitions of the parameters can be obtained from the fifth embodiment, which is not described herein again. The definitions of the parameters in fig. 18 and fig. 19 can be derived from the first embodiment, and are not repeated herein. In the eighth embodiment, before focusing, as the spatial frequency of each section increases, the imaging quality shows a rapid falling trend; after focusing, the imaging quality shows a slow descending trend as the spatial frequency of each interval increases. It can be seen that the imaging quality is significantly improved after focusing.

Watch 15

TABLE 16

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Finally, it should be noted that the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting, and although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A focusing apparatus, comprising, from an object side to an image side along an optical axis:

the image side surface of the light guide layer is flexible; and

the object side of the electro-deformation layer is glued with the image side of the light guide layer, and the image side of the light guide layer deforms after the electro-deformation layer is electrified and drives the image side of the light guide layer to deform.

2. The focusing apparatus of claim 1 wherein the light guiding layer is made of a flexible polymer and the electro-deformable layer is made of a piezoelectric material.

3. The focusing mechanism of claim 1 wherein the light guiding layer is a liquid-filled lens, the light guiding layer being filled with a liquid, and wherein the liquid is forced within the light guiding layer by the electro-deformable layer, thereby causing redistribution of the liquid within the cavity of the light guiding layer and a change in curvature of the surface of the light guiding layer.

4. The focusing device of claim 1, further comprising a protective layer, wherein the protective layer, the light guide layer and the electro-deformable layer are attached in sequence, and the thickness of the electro-deformable layer ranges from 0.02mm to 0.1 mm.

5. The focusing arrangement of claim 1 wherein the object side surface of the electro-deformable layer has a radius of curvature R at the optical axis₁，R₁The following relation is satisfied: -500mm < R₁Less than 500 mm; the curvature radius of the image side surface of the electrostrictive layer at the optical axis is R₂，R₂The following relation is satisfied: -500mm < R₂＜500mm。

6. The focusing apparatus of claim 1 wherein the focusing apparatus has a thickness on the optical axis in the range of 0.510mm to 0.580 mm.

7. An optical imaging system comprising a focusing apparatus according to any one of claims 1 to 6, wherein the optical imaging system further comprises a lens assembly, and wherein the focusing apparatus is disposed on an object side of the lens assembly or within the lens assembly.

8. The optical imaging system of claim 7, wherein the lens assembly comprises, from object side to image side:

a first lens element with refractive power having a convex object-side surface at paraxial region;

a second lens element with refractive power;

a third lens element with refractive power;

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

9. The optical imaging system of claim 8, wherein the focusing means is disposed at an object side of the first lens or between the second lens and a third lens.

10. An image capturing module, comprising a photosensitive element and the optical imaging system according to any one of claims 7 to 9, wherein the photosensitive element is disposed on an image side of the optical imaging system.

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