WO2020006767A1

WO2020006767A1 - Liquid lens and manufacturing method therefor, and imaging module

Info

Publication number: WO2020006767A1
Application number: PCT/CN2018/094917
Authority: WO
Inventors: 蒋鹏
Original assignee: 深圳市汇顶科技股份有限公司
Priority date: 2018-07-06
Filing date: 2018-07-06
Publication date: 2020-01-09
Also published as: CN109073793A; CN109073793B

Abstract

The present application relates to the technical field of imaging module manufacturing, and provides a liquid lens and a manufacturing method therefor, and an imaging module. The liquid lens comprises at least one substrate layer; the substrate is provided with N substrate through-holes, wherein N is a natural number that is greater than or equal to 1; each substrate through-hole is provided therein with a driver portion connected to a lens driver circuit; the substrate is further provided with a first sealing layer and a second sealing layer, wherein the first sealing layer, the second sealing layer, and the substrate through-hole form a lens cavity, the lens cavity being provided with a liquid medium; each substrate through-hole is provided with a sealing layer used to separate the liquid medium and the driver portion. With the embodiments of the present application, a product can be adjustable in size and processed and assembled more easily, automatic batch production can be easily realized, and costs can be reduced.

Description

Liquid lens, processing method thereof, and imaging module

Technical field

The present application relates to the technical field of imaging equipment manufacturing, and in particular, to a liquid lens, a processing method thereof, and an imaging module.

Background technique

With the rapid development of terminal services, simple and portable camera equipment is becoming more and more popular. With the development of technology, various ultra-thin focus lenses are gradually appearing, such as zoom cameras for mobile phones that include a voice coil focus motor and mechanical zoom lenses.

The inventors found that the prior art has at least the following problems: the small volume of the voice coil focusing device causes inconvenient assembly, and the cost of the entire camera module is high; the mechanical zoom lens has a large volume, and is not easy to miniaturize and integrate; existing The electrowetting liquid lens is too large to be suitable for macro imaging, and it is not easy to automate large-scale processing. The electrowetting liquid lens that has been disclosed is too large and has a long focal length, which is not suitable for macro imaging.

Summary of the invention

The purpose of some embodiments of the present application is to provide a liquid lens, a processing method thereof, and an imaging module, so that the product size can be flexibly adjusted, processing and assembly are more convenient, it is easy to automate mass production, and it is beneficial to reduce costs.

An embodiment of the present application provides a liquid lens including at least one substrate. The substrate is provided with N substrate through holes, where N is a natural number greater than or equal to 1. Each of the substrate through holes is provided with a lens driver. A driving part for circuit connection; the substrate is further provided with a first sealing layer and a second sealing layer, and the first sealing layer, the second sealing layer, and the substrate through hole form a lens cavity, and the lens cavity A liquid medium is provided; an insulating layer for isolating the liquid medium and the driving portion is provided in each of the through holes of the substrate.

An embodiment of the present application further provides an imaging module, including the liquid lens as described above, and an image sensor. The image sensor is fixedly connected to the liquid lens, and a photosensitive area of the image sensor is in contact with the liquid. The substrate through hole of the lens corresponds.

An embodiment of the present application further provides a liquid lens processing method, including: providing a substrate; opening N substrate through holes on the substrate, where N is a natural number greater than or equal to 1; A driving part connected to a lens driving circuit; forming an insulating layer on the driving part; forming a first sealing layer on the substrate for sealing one end of the substrate through hole; injecting a liquid medium into the substrate through hole; A second sealing layer is formed on the substrate for sealing the other end of the through hole of the substrate to obtain a single-layer liquid lens.

Compared with the prior art, the embodiments of the present application form a substrate through hole in the substrate, and form a driving part (ie, a driving electrode for the lens) connected to the lens driving circuit and an insulating layer in the substrate through hole, and then combine and provide the substrate with the substrate. The first sealing layer and the second sealing layer on the substrate seal the through hole of the substrate to form a lens cavity, thereby forming a main structure of the liquid lens. Since the main structure of the lens can be produced by a mature and stable plane processing technology related to the printed circuit board, and can be connected and assembled with the peripheral circuits such as the image sensor and the lens driving circuit through the plane processing technology, the liquid of this embodiment is The assembly of the lens and the peripheral circuit is more convenient, and in this embodiment, it is easier to implement array processing. At the same time, the planar processing process can make the product thinner, smaller in volume, and lower in cost.

In addition, the driving part includes a first metal layer and a conductive member; the first metal layer is formed on an inner wall of the substrate through hole, and the conductive member is installed in the substrate through hole in a tight fit; The surface of the conductive member is an annular slope surface. In this embodiment, the original curvature of the liquid medium can be determined by the gradient of the annular slope surface of the conductive member, so that liquid lenses with different original curvatures can be flexibly manufactured.

In addition, the driving portion is a metal layer having a circular slope surface on the surface. This embodiment can manufacture liquid lenses with different original curvatures in a more simplified process.

In addition, the liquid lens further includes a bottom plate and a lens driving circuit; the bottom plate is stacked and disposed on the light exit side of the substrate, and the bottom plate is provided with N bottom plate through holes, which are the same as the substrate through holes. The lens driving circuit is disposed on the base plate and is electrically connected to the driving portion. In this embodiment, not only the interconnection between the liquid lens and the lens driving circuit can be conveniently implemented through the bottom plate, but also the focal length can be easily adjusted by adjusting the thickness of the bottom plate.

In addition, the liquid lens further includes a second metal layer formed on at least one surface of the substrate. The second metal layer in this embodiment may be used for electromagnetic shielding or forming a pad layer.

In addition, the substrate is a flexible substrate, and a reinforcing layer is provided on a light incident side of the flexible substrate.

In addition, a black layer is placed on areas of the substrate other than the lens cavity, thereby reducing stray light.

In addition, the insulating layer is a black insulating layer. Stray light can be better reduced by the black insulating layer.

BRIEF DESCRIPTION OF THE DRAWINGS

One or more embodiments are exemplified by the pictures in the accompanying drawings. These exemplary descriptions do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the drawings in the drawings do not constitute a limitation on scale.

1 is a schematic structural diagram of a single-layer single-hole liquid lens according to a first embodiment of the present application;

2 is a schematic structural diagram of an array type liquid lens according to a first embodiment of the present application;

3 is a schematic structural diagram of a multilayer liquid lens according to a first embodiment of the present application;

4 is a schematic structural diagram of a liquid lens according to a second embodiment of the present application;

5 is a schematic structural diagram of a single-layer lens imaging module according to a third embodiment of the present application;

6 is a schematic structural diagram of an imaging module of a multilayer lens according to a third embodiment of the present application;

7 is a schematic structural diagram of an imaging module with a conductive member according to a third embodiment of the present application;

FIG. 8 is a flowchart of a liquid lens processing method according to a fourth embodiment of the present application.

detailed description

In order to make the purpose, technical solution, and advantages of the present application clearer, some embodiments of the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the application, and are not used to limit the application.

The embodiment of the present application relates to a liquid lens, which may also be referred to as an Electrowetting (EW) liquid lens. The liquid lens may be used to converge and diverge light in an optical system. For example, it can be applied to optical detection equipment, which can be used to perform optical measurements, such as optical ranging, biometrics (including faces, optical fingerprints under the screen, iris, etc.); or can be applied to Charge-coupled devices (Charge-Coupled devices, CCDs), CMOS image sensors (CMOS, Image Sensors, CIS) and other optical imaging modules, or can also be used for light field imaging modules and laser modulation of lasers.

Please refer to FIGS. 1 to 3. The liquid lens according to the first embodiment of the present application includes: at least one substrate 100, and the substrate 100 is provided with N substrate through holes 102, where N is a natural number greater than or equal to 1, and each substrate through hole A driving section 103 connected to the lens driving circuit 120 is provided in 102. The substrate 100 is further provided with a first sealing layer 105 and a second sealing layer 106. The first sealing layer 105, the second sealing layer 106, and the substrate through hole 102 are formed. The lens cavity is provided with a liquid medium therein, and each substrate through hole 102 is provided with an insulating layer 104 for isolating the liquid medium and the driving portion 103.

Specifically, the substrate 100 may be a flexible substrate in a flexible printed circuit (FPC) process, or a rigid substrate in a printed circuit board (PCB) process. The flexible substrate may be suitable for processing thickness. With thinner and smaller liquid lenses, hard substrates are suitable for processing larger size liquid lenses. This embodiment is mainly described by using the FPC processing technology to process a liquid lens as an example. However, any liquid lens structure realized by using a planar processing technology such as FPC or PCB is within the protection scope of this embodiment. The flexible substrate may be a polyimide (PI) or polyester (Polyester, PE) film. The substrate 100 may be printed with a circuit. Optionally, a second metal layer 101 may be formed on the upper and lower surfaces of the substrate 100. The second metal layer 101 is, for example, a copper-clad layer. The second metal layer 101 may be used for electromagnetic shielding or for electromagnetic shielding. Form a pad layer.

FPC processing technology can process through holes, blind holes and buried holes. The main function of the hole in the FPC is to achieve inter-layer interconnection. In this embodiment, the main function of the substrate through hole 102 is to set the driving electrode of the liquid lens and form the lens cavity. Specifically, one or more substrate through-holes 102 may be formed on the substrate 100. Please refer to FIG. 2, the plurality of substrate through-holes 102 may be arranged in an array manner or arranged in other irregular manners. The substrate through-hole 102 can be obtained by laser drilling equipment, but is not limited to this, so that the liquid lens can be automated batch processing, and the arrayed liquid lens can be easily realized. At the same time, the substrate through-hole 102 has high accuracy and easier control of tolerances. , High consistency of array processing. The shape of the substrate through-hole 102 may be circular, but it is not limited thereto. In some examples, it may also be rectangular or hexagonal. The size of the substrate through hole 102 can be set according to actual needs. For example, when the substrate through hole 102 is processed by a laser drilling device, the diameter of the substrate through hole 102 can reach 20 micrometers (um). Therefore, the size of the liquid lens It can be made smaller, and the substrate drilling process is mature and stable. Compared with the existing stainless steel hollow round tube structure, the size of the substrate through-hole 102 is more flexible.

In this embodiment, the driving part 103 is, for example, a metal layer with a uniform thickness formed on the inner wall of each substrate through-hole 102, such as a copper-clad layer. The copper-clad layer can be obtained by using an electroplating process in the FPC processing process, which can be specifically performed as required For the thickness of the copper-clad layer, a suitable electroplating process is selected, such as evaporation, sputtering, and water plating, and the details will not be repeated here. The driving section 103 may be electrically connected to the lens driving circuit 120 (see below) through a trace on the substrate 100. In this embodiment, the driving portion 103 may extend to the upper and lower surfaces of the substrate 100, so that a three-dimensional three-dimensional structure driving electrode may be formed, but it is not limited thereto. In this way, the driving portion 103 can better drive the liquid medium in the lens cavity to move in a direction where the surface tension and the electric field force are balanced. Compared with the existing liquid lens with a metal package structure, the processing process of the driving part 103 of the liquid lens of this embodiment is mature, stable, low cost, and suitable for automated batch processing.

In this embodiment, the insulating layer 104 is formed on the surface of the driving portion 103 and can be used to isolate the driving portion 103 from the liquid medium. When a driving signal is applied to the driving portion 103, the driving portion 103 can prevent an electrochemical reaction between the driving portion 103 and the liquid medium. Specifically, the insulating layer 104 may be a waterproof and oil-proof insulating layer. In practical applications, the insulating layer 104 may be formed by depositing an adhesive layer on the surface of the driving portion 103. The material of the adhesive layer is, for example, Paracyclophane, and the thickness may be several hundred nanometers. The plating or baking process forms a layer of polytetrafluoroethylene (Teflon) material or other fluorine-containing plastic on the adhesive layer to form an insulating layer 104; or, a titanium dioxide hydrophobic layer can be sprayed on the adhesive layer to achieve The surface of the insulating layer 104 and the titanium dioxide layer has a micro-nano hydrophobic structure similar to lotus leaves, which has a better hydrophobic effect, but it should not be limited to this. Any insulating layer that can achieve the desired effect is within the protection scope of this embodiment. . The thickness of the insulating layer 104 can be set according to actual needs. In general, the thickness of the insulating layer 104 can be selected between 500 nanometers (nm) and 50 micrometers (um). In some examples, the thickness of the insulating layer 104 is, for example, 1 um. ～ 2um, so that a small-sized liquid lens can be obtained, which is beneficial to the thinning and thinning of the imaging module to which it is applied. In this embodiment, the liquid medium may include non-polar liquids and polar liquids with different refractive indices. The non-polar liquid is, for example, transparent silicone oil, such as methyl silicone oil or organic silicone oil, and the polar liquid is, for example, ionized water, or other Molecular ionic liquids, of course, are not limited to this. In practical applications, two liquids with different refractive indices and close densities can be selected as the liquid medium. In some examples, the liquid medium may be two or more, such as three. Optionally, a black insulating layer can also be obtained through a blackening process, and a black insulating layer 104 is provided on the driving portion 103. The black insulating layer can be obtained, for example, by adding a black pigment, but is not limited to this. The black insulating layer can reduce reflected stray light. The two liquid media in the lens cavity will automatically delaminate due to differences in surface tension and the like, and form a naturally curved optical interface. Because the insulating layer 104 has a different affinity for transparent silicone oil and ionic liquids, the combined force of the insulating layer 104's wettability, the adhesion between the molecules of the liquid medium, and the surface tension of the liquid medium can be much larger than the liquid medium itself. The gravity and external impact force make the liquid medium in the lens cavity have a very stable optical structure. As shown in Figures 1 to 3, the liquid medium in the transparent cavity forms a stable double-layer structure.

In this embodiment, the first sealing layer 105 and the second sealing layer 106 are respectively used to seal the bottom and the top of the through-hole 102 of the substrate, and therefore, they must have a certain water and oil resistance. Both the first sealing layer 105 and the second sealing layer 106 can be realized by using a transparent plastic film. The transparent plastic film can be formed on the upper and lower surfaces of the substrate 100 through a planar processing process, but the first sealing layer 105 and the second sealing layer are not limited thereto. 106 may also be implemented by thin glass, for example, the thin glass is adhered to the upper and lower surfaces of the substrate 100 to achieve sealing of the substrate through-hole 102, which will not be repeated here. It should be noted that, when processing the first sealing layer 105 and the second sealing layer 106, the substrate 100 can play a supporting role, thereby facilitating the processing of the first sealing layer 105 and the second sealing layer 106. After the first sealing layer 105 is processed, an appropriate amount of liquid medium can be injected into the lens cavity, such as an equal volume of transparent silicone oil and ionic liquid, and then the second sealing layer 106 is processed to complete a single layer of liquid. lens. Because it is a planar processing process, the first sealing layer 105 and the second sealing layer 106 are also easy to implement automated batch processing.

It is worth mentioning that the liquid lens may further include a base plate 110 and a lens driving circuit 120. The bottom plate 110 is stacked on the light-emitting side of the substrate 100, and the bottom plate 110 is provided with N bottom plate through holes 111. The bottom plate through holes 111 are coaxially disposed with the substrate through hole 102. The lens driving circuit 120 is provided on the bottom plate 110 and is connected to the driving portion 103 Electrical connection. Specifically, the bottom plate 110 may be a flexible substrate or a rigid substrate, and the bottom plate 110 may be adhered and disposed on the light-emitting side of the substrate 100, for example, disposed on the bottom surface of the substrate 100. The base plate 110 includes, for example, a support area coinciding with the substrate 100 and a load-bearing area extending from the support area. The lens driving circuit 120 can be disposed in the load-bearing area of the base plate 110, so that the lens drive circuit 120 and the lens drive electrodes can be realized by a planar processing process. (Ie, the driving unit 103). Of course, an interface can also be provided on the substrate 100 to achieve electrical connection with the lens driving circuit 120 to be compatible with the independent lens driving circuit 120. The base plate 110 can not only support the first sealing layer 105, but also can be used to assist in determining the focal length of the liquid lens. For example, when short focal length imaging is required, the thickness of the base plate 110 can be reduced. When larger focal length imaging is required, In this case, the thickness of the base plate 110 can be increased, thereby changing the distance between the light-emitting surface of the liquid lens and the image sensor (see below). It is worth mentioning that, in some examples, the set focal length can also be achieved through the image sensor structure. For example, the image sensor chip can be sunk into the sensor substrate, so that the focal length is determined by the thickness of part of the sensor substrate.

When the substrate 100 is a flexible substrate, a reinforcing layer 19 may also be provided on the light incident side of the flexible substrate. The reinforcing layer 19 may be a metal sheet or other plastic sheet having a certain strength, thereby improving the strength of the liquid lens. Optionally, a blackening process may also be performed on the substrate 100, for example, spraying a black layer, such as black paint, on an area other than the lens cavity on the light-incident side of the substrate 100, thereby reducing stray light.

Figures 1 and 2 show single-layer single-hole and porous liquid lenses, respectively, and Figure 3 shows a multilayer liquid lens. Specifically, each layer of the liquid lens can be manufactured separately, and then the multilayer liquid lens is aligned and fixedly connected to obtain a multilayer liquid lens. The substrate through-holes 102 of each layer of the liquid lens are coaxially aligned, and each layer of the liquid lens can Bonded together by pasting. Specifically, the diameters of the substrate through-holes 102 of the liquid lenses of each layer may be the same, may be sequentially reduced from top to bottom, or may be sequentially increased. Each of the multi-layer liquid lenses may be a single-hole liquid lens or an arrayed porous liquid lens. It is worth mentioning that each lens in the liquid lens can be individually focused. In this way, in a multi-layer liquid lens, each layer of the liquid lens can be individually focused, and a multi-layer focusing combination can achieve a richer focusing effect.

Optionally, in a multi-layer liquid lens structure, an intermediate substrate 130 may also be provided between two adjacent layers of liquid lenses. The intermediate substrate 131 also needs to have intermediate substrate through holes 131, and each intermediate substrate through hole 131 communicates with the substrate. The holes 102 are arranged coaxially, and the intermediate substrate 130 can be used to assist in setting the focal length. In some examples, the intermediate substrate 130 may not be provided.

It is worth mentioning that with the liquid lens structure of this embodiment, the diameter of the through hole of the substrate can be made small, not only can the liquid light entrance diameter reach 0.4 mm and below, but also the focal length can reach 0.8 mm and below. It can be applied to macro imaging applications, such as under-screen optical fingerprint recognition, but the existing liquid lens processing technology is difficult to achieve.

Compared with the prior art, this embodiment obtains the main structure of the liquid lens through a planar processing process such as FPC and PCB, so that the product size can be adjusted more flexibly, the product volume is smaller, and the thickness is thinner, which is easy to implement arraying High degree of processing and automation, high batch processing efficiency, more convenient connection and assembly with peripheral circuits such as image sensors, lens driving circuits, etc., which is conducive to reducing costs.

The second embodiment of the present application relates to a liquid lens. The second embodiment is an improvement on the basis of the first embodiment. The main improvement is that in this embodiment, the driving portion has a specific surface shape, which is convenient. The liquid lens achieves the required original curvature.

Referring to FIG. 4, in the liquid lens of this embodiment, the driving portion 103 includes a first metal layer 1030 and a conductive member 1031. The first metal layer 1030 is formed on an inner wall of the substrate through-hole 102, and the conductive member 1031 is mounted on the substrate in a tight fit. In the through hole 102, the surface of the conductive member 1031 (that is, the surface facing the liquid medium) is an annular slope surface.

The radius of the two liquid media in the lens cavity, such as the contact surface radius of transparent silicone oil and ionic liquid, is called the radius of curvature. The radius of curvature of the liquid medium when no driving signal is applied is called the original curvature. When a driving signal is applied through the lens driving circuit 120 The electric field is applied to the liquid medium by the driving part. Under the combined effects of electric field force, affinity of the insulating layer, and surface tension, the radius of the contact surface between the ionic liquid and the transparent silicone oil changes, that is, the radius of curvature changes, and accordingly the liquid The focal length of the lens changes to achieve the zoom function.

In this embodiment, the conductive member 1031 having a circular slope surface is embedded in the substrate through hole 102, and the required original curvature can be obtained according to the slope of the slope surface of the conductive member 1031. Therefore, by setting a specific slope, The conductive parts of the annular slope surface can conveniently and accurately achieve the required original curvature. Specifically, the conductive member 1031 may be a micro-metal member, such as a miniature stainless steel member, or other devices having good conductive properties. The conductive member 1031 can be embedded in the through hole 102 of the substrate in a zero-fit or interference fit manner, thereby ensuring a good driving ability of the driving portion 103. In practical applications, the slope of the annular slope can be between 10 and 45 degrees, but it is not limited to this.

It should be noted that, in some examples, the driving part 103 may also be a metal layer with a ring-shaped ramp surface on the surface. Specifically, when the driving part 103 is formed by electroplating, the thickness of the metal layer may be controlled through a mask template, so that the formation The surface of the metal layer is a circular slope surface with a desired slope, but it is not limited thereto. It is worth mentioning that in some examples, the annular slope surface can also be implemented by the insulating layer 104. Since the thickness of the insulating layer having the structure of the annular slope surface may be large, the driving signal may need to be increased when zooming.

Compared with the foregoing embodiment, the present embodiment is provided with a ring-shaped slope surface structure in the through hole of the substrate, thereby facilitating the realization of the required original curvature and improving the flexibility of manufacturing the liquid lens.

The third embodiment of the present application relates to an imaging module, which can be used to implement photographing or biometric identification, such as under-screen fingerprint identification, etc. This embodiment does not specifically limit the specific application of the imaging module.

Please refer to FIG. 5 to FIG. 7, the imaging module includes a liquid lens according to the first or second embodiment, and an image sensor 20. The image sensor 20 is fixedly connected to the liquid lens, and the photosensitive area of the image sensor 20 corresponds to the substrate through hole 102 of the liquid lens.

Specifically, the image sensor 20 is disposed on a sensor substrate 21, and the sensor substrate 21 is fixedly connected to the liquid lens, such as an adhesive connection. The photosensitive area of the image sensor 20 may be coaxially aligned with the substrate through hole 102 of the liquid lens. The imaging module further includes a lens driving circuit 120. The lens driving circuit 120 may be disposed on the base plate 110 of the liquid lens, or may be connected to the liquid lens as an independent component. 5 and FIG. 6 respectively show an imaging module including a single-layer and a multi-layer liquid prism. It should be noted that each layer of the liquid prism may also be an arrayed liquid prism. FIG. 7 shows a single-layer, single-hole imaging module including a liquid prism having a driving portion whose surface is an annular slope surface. The liquid prism in the imaging module shown in FIG. 7 may also be a single-layer porous or Multilayer porous liquid prism.

Compared with the prior art, since the main structure of the liquid lens is obtained through a planar processing process in this embodiment, the liquid lens can be conveniently connected to a peripheral circuit such as a lens driving circuit and an image sensor through a planar processing process such as sticking. , Assembly, high degree of automation, simplified assembly procedures, shortened processing cycle, low cost.

The fourth embodiment of the present application relates to a liquid lens processing method for processing to obtain the liquid lens according to the first or second embodiment. Referring to FIG. 8, the processing method includes steps 801 to 807. For the structure of the liquid lens manufactured by the method of this embodiment, please refer to FIG. 1 to FIG. 3.

Step 801: Provide a substrate.

Specifically, the substrate 100 may be a flexible substrate in an FPC processing process, or a rigid substrate in a PCB processing process. This embodiment is mainly described by using an FPC processing process to process a liquid lens as an example. The flexible substrate may be a polyimide (PI) or polyester (Polyester, PE) film. Compared with liquid lenses in the form of rigid substrates and metal packages, flexible substrates can produce liquid lenses that are smaller and thinner. The substrate 100 may form a trace, for example, a trace for connecting the lens driving circuit 120 and the driving section 103. The second metal layer 101 can be formed on at least one side of the substrate 100. For example, the second metal layer 101 can be formed on both sides of the substrate 100. The second metal layer 101 is, for example, a copper-clad layer. The second metal layer 101 can also be used for electromagnetic shielding. Can be used to form a pad layer.

Step 102: N substrate through holes are opened on the substrate, and N is a natural number greater than or equal to 1.

FPC processing technology can process through holes, blind holes and buried holes. The main function of the hole in the FPC is to achieve inter-layer interconnection. In this embodiment, the main function of the substrate through hole 102 is to set the driving electrode of the liquid lens and form the lens cavity. Specifically, the substrate through-hole 102 can be obtained by laser drilling equipment, but is not limited to this. Any method capable of opening the substrate through-hole 102 on the substrate 100 is within the protection scope of this embodiment. Through laser drilling equipment, through-holes of substrates with a diameter of 20 μm can be processed, thereby processing very small liquid lenses. In addition, processing methods such as laser drilling are easy to achieve automated batch processing, and array liquid lenses can be easily realized. At the same time, the substrate through-hole 102 has high accuracy, easier control of tolerances, high consistency in array processing, and a substrate punching process. Mature and stable, compared with the existing stainless steel hollow round tube structure, the size of the through hole 102 of the substrate is more flexible. The number of the substrate through-holes 102 may be one shown in FIG. 1 and a plurality shown in FIG. 2. The plurality of substrate through-holes 102 may be arranged in an array. The substrate through-hole 102 may be circular, rectangular, hexagonal, etc., and the shape of the substrate through-hole is not specifically limited in this embodiment.

Step 103: A driving part connected to the lens driving circuit is provided in the through hole of the substrate.

Specifically, referring to FIG. 1, the driving part 103 is, for example, a metal layer with a uniform thickness formed on the inner wall of each substrate through-hole 102, such as a copper-clad layer. An appropriate electroplating process can be selected according to the thickness of the required copper-clad layer, such as evaporation, sputtering, and water plating, and the details will not be repeated here. In this embodiment, the driving portion 103 may extend to the upper and lower surfaces of the substrate 100, so that a three-dimensional three-dimensional structure driving electrode may be formed, but it is not limited thereto. Compared with the existing liquid lens with a metal package structure, the processing process of the driving part 103 of the liquid lens of this embodiment is mature, stable, low cost, and suitable for automated batch processing.

Referring to FIG. 4, in an example, the driving portion 103 has a specific surface shape, so that the liquid lens can achieve the required original curvature. Specifically, the driving part 103 may include a first metal layer 1030 and a conductive member 1031. The surface of the conductive member 1031 is a circular slope surface. The first metal layer 1030 may be electrically connected to the lens driving circuit 120 through a trace on the substrate 100. For the driving part 103, step 103 specifically includes: forming a first metal layer 1030 on the inner wall of the substrate through hole 102 by electroplating, and embedding the conductive member 1031 in the substrate through hole 102. The first metal layer 1030 may be a copper-clad layer with a uniform thickness. The first metal layer 1030 may extend to the upper and lower surfaces of the substrate 100, so that a three-dimensional structure driving electrode may be formed. In this embodiment, the conductive member 1031 having a circular slope surface is embedded in the substrate through hole 102, and the required original curvature can be obtained according to the slope of the slope surface of the conductive member 1031. Therefore, by setting a specific slope, The conductive parts of the annular slope surface can conveniently and accurately achieve the required original curvature. Specifically, the conductive member 1031 may be a micro-metal member, such as a miniature stainless steel member, or other devices having good conductive properties. The conductive member 1031 can be embedded in the through hole 102 of the substrate in a zero-fit or interference fit manner, thereby ensuring a good driving ability of the driving portion 103. In practical applications, the slope of the circular slope surface can take a value between 10 and 45 degrees, but it is not limited to this. It should be noted that, in some examples, the driving part 103 may also be a metal layer with a circular slope surface on the surface. Specifically, in step 103, the driving part 103 is formed by depositing on the inner wall of the substrate through-hole 102 through a mask process. The thickness of the metal layer is controlled by the mask template, so that the surface of the formed metal layer is a circular slope surface having a desired slope, but it is not limited thereto. By providing a ring-shaped slope surface structure in the through hole of the substrate, it is convenient to realize the required original curvature, and the flexibility of liquid lens manufacturing is improved.

Step 104: An insulating layer 104 is formed on the driving part 103.

Specifically, the insulating layer 104 is formed on the surface of the driving portion 103 and can be used to isolate the driving portion 103 and the liquid medium. Specifically, the insulating layer 104 may be a waterproof and oil-proof insulating layer. In practical applications, the insulating layer 104 may be formed by depositing an adhesive layer on the surface of the driving portion 103. The material of the adhesive layer is, for example, Paracyclophane, and the thickness may be several hundred nanometers. The plating or baking process forms a layer of polytetrafluoroethylene (Teflon) material or other fluorine-containing plastic on the adhesive layer to form an insulating layer 104; or, a titanium dioxide hydrophobic layer can be sprayed on the adhesive layer to achieve The surface of the insulating layer 104 and the titanium dioxide layer has a micro-nano hydrophobic structure similar to lotus leaves, which has a better hydrophobic effect, but it should not be limited to this. Any insulating layer that can achieve the desired effect is within the protection scope of this embodiment. . The thickness of the insulating layer 104 can be set according to actual needs. In some examples, the thickness of the insulating layer 104 is, for example, 1 um to 2 um, so that a small-sized liquid lens can be obtained, which is beneficial to the thinning and thinning of the imaging module to which it is applied. Optionally, a black insulating layer can also be obtained through a blackening process, and a black insulating layer 104 is provided on the driving portion 103. The black insulating layer can be obtained, for example, by adding a black pigment, but is not limited thereto.

Step 105: forming a first sealing layer on the substrate for sealing one end of the through hole of the substrate.

Step 106: Inject a liquid medium into the through hole of the substrate.

Specifically, the liquid medium may be a transparent silicone oil and an ionic liquid. The two liquid media in the lens cavity will automatically delaminate due to differences in surface tension and the like, and form a naturally curved optical interface. Because the insulating layer 104 has a different affinity for transparent silicone oil and ionic liquids, the combined force of the insulating layer 104's wettability, the adhesion between the molecules of the liquid medium, and the surface tension of the liquid medium can be much larger than the liquid medium itself. The gravity and external impact force make the liquid medium in the lens cavity have a very stable optical structure. As shown in Figures 1 to 3, the liquid medium in the transparent cavity forms a stable double-layer structure.

Step 107: forming a second sealing layer on the substrate for sealing the other end of the through hole of the substrate to obtain a single-layer liquid lens.

Specifically, the first sealing layer 105 and the second sealing layer 106 in

steps

106 and 107 are used to seal the bottom and top of the through-hole 102 of the substrate, respectively, so they must have a certain water and oil resistance. Both the first sealing layer 105 and the second sealing layer 106 can be realized by using a transparent plastic film or thin glass. For example, the thin glass can be adhered to the upper and lower surfaces of the substrate 100 to seal the substrate through hole 102. It should be noted that, when the first sealing layer 105 and the second sealing layer 106 are processed, the substrate 100 can play a supporting role, thereby facilitating the processing of the first sealing layer 105 and the second sealing layer 106. After the first sealing layer 105 is processed, an appropriate amount of liquid medium can be injected into the lens cavity, such as an equal volume of transparent silicone oil and ionic liquid, and then the second sealing layer 106 is processed to complete a single layer of liquid. lens. Because it is a planar processing process, the first sealing layer 105 and the second sealing layer 106 are also easy to implement automated batch processing.

It is worth mentioning that the bottom plate 100 can also be provided on the light-emitting side of the substrate 100, for example, the bottom plate is adhered to the substrate 100, and the lens driving circuit 120 is set on the bottom plate. The bottom plate 110 may have the same number of bottom plate through holes 111 as the number of the substrate through holes 102, and the bottom plate through holes 111 are coaxially disposed with the substrate through holes 102. The base plate 110 can not only support the first sealing layer 105, but also can be used to assist in determining the focal length of the liquid lens. For example, when short focal length imaging is required, the thickness of the base plate 110 can be reduced. When larger focal length imaging is required, In this case, the thickness of the base plate 110 can be increased, thereby changing the distance between the light-emitting surface of the liquid lens and the image sensor. It is worth mentioning that, in some examples, the set focal length can also be achieved through the image sensor structure. For example, the image sensor chip can be sunk into the sensor substrate, so that the focal length is determined by the thickness of part of the sensor substrate.

When the substrate 100 is a flexible substrate, after step 807, a reinforcing layer may be further provided on the light incident side of the flexible substrate. The reinforcing layer 19 may be a metal sheet or other plastic sheet having a certain strength, thereby improving the strength of the liquid lens. Optionally, a blackening process may also be performed on the substrate 100, for example, spraying a black layer, such as black paint, on an area other than the lens cavity on the light-incident side of the substrate 100, thereby reducing stray light.

After step 807, a plurality of single-layer liquid lenses may be prepared through steps 801 to 807, and a plurality of single-layer liquid lenses may be stacked to form a multi-layer liquid lens. Specifically, each layer of the liquid lens can be manufactured separately, and then the multilayer liquid lens is aligned and fixedly connected to obtain a multilayer liquid lens. The substrate through-holes 102 of each layer of the liquid lens are coaxially aligned, and each layer of the liquid lens can Bonded together by pasting. Specifically, the diameters of the substrate through-holes 102 of the liquid lenses of each layer may be the same, may be sequentially reduced from top to bottom, or may be sequentially increased. Each of the multi-layer liquid lenses may be a single-hole liquid lens or an arrayed porous liquid lens. It is worth mentioning that each lens in the liquid lens can be individually focused. In this way, in a multi-layer liquid lens, each layer of the liquid lens can be individually focused, and a multi-layer focusing combination can achieve a richer focusing effect.

Compared with the prior art, this embodiment obtains the main structure of the liquid lens through a planar processing process such as FPC and PCB, so that the product size can be adjusted more flexibly, the product volume is smaller, and the thickness is thinner, which is easy to implement arraying. High degree of processing and automation, high batch processing efficiency, more convenient connection and assembly with peripheral circuits such as image sensors, lens driving circuits, etc., which is conducive to reducing costs.

Those of ordinary skill in the art can understand that the foregoing embodiments are specific embodiments for implementing the present application, and in practical applications, various changes can be made in form and details without departing from the spirit and range.

Claims

A liquid lens, comprising at least one substrate;

The substrate is provided with N substrate through holes, N is a natural number greater than or equal to 1;

A driving portion connected to the lens driving circuit is provided in each of the substrate through holes;

The substrate is further provided with a first sealing layer and a second sealing layer, the first sealing layer, the second sealing layer, and the substrate through hole forming a lens cavity, and a liquid medium is provided in the lens cavity;

An insulation layer for isolating the liquid medium and the driving part is provided in each of the substrate through holes.
The liquid lens according to claim 1, wherein the driving portion includes a first metal layer and a conductive member;

The first metal layer is formed on an inner wall of the through hole of the substrate, and the conductive member is installed in the through hole of the substrate in a tight fit; wherein a surface of the conductive member is a circular slope surface.
The liquid lens according to claim 1, wherein the driving portion is a metal layer having a circular slope surface on the surface.
The liquid lens according to claim 1, wherein the liquid lens further comprises a base plate and a lens driving circuit;

The bottom plate is stacked and arranged on the light-emitting side of the substrate, the bottom plate is provided with N bottom plate through holes, the bottom plate through holes are arranged coaxially with the substrate through holes, and the lens driving circuit is provided on the bottom plate, And is electrically connected to the driving part.
The liquid lens of claim 1, wherein the liquid lens further comprises a second metal layer formed on at least one surface of the substrate.
The liquid lens according to claim 1, wherein the substrate is a flexible substrate, and a light-incident side of the flexible substrate is provided with a reinforcing layer.
The liquid lens according to claim 1, wherein a black layer is disposed on an area of the substrate except the lens cavity.
The liquid lens according to any one of claims 1 to 7, wherein the insulating layer is a black insulating layer.
An imaging module, comprising the liquid lens according to any one of claims 1 to 8, and

An image sensor, the image sensor is fixedly connected to the liquid lens, and a photosensitive area of the image sensor corresponds to a substrate through hole of the liquid lens.
A liquid lens processing method, comprising:

Providing a substrate;

Opening N substrate through holes on the substrate, N being a natural number greater than or equal to 1;

Providing a driving part connected to the lens driving circuit in the substrate through hole;

Forming an insulating layer on the driving part;

Forming a first sealing layer on the substrate for sealing one end of the through hole of the substrate;

Injecting a liquid medium into the through hole of the substrate;

A second sealing layer is formed on the substrate for sealing the other end of the through hole of the substrate to obtain a single-layer liquid lens.
The method for processing a liquid lens according to claim 10, wherein the driving portion includes a first metal layer and a conductive member; a surface of the conductive member is a circular slope surface;

The setting of a driving part connected to the lens driving circuit in the through hole of the substrate specifically includes:

Forming the first metal layer on the inner wall of the through hole of the substrate by electroplating;

The conductive member is embedded in the through hole of the substrate.
The method for processing a liquid lens according to claim 10, wherein the driving portion is a metal layer whose surface is a circular slope surface;

The setting of a driving part connected to the lens driving circuit in the through hole of the substrate specifically includes:

The driving portion is formed by depositing on the inner wall of the through hole of the substrate through a mask process.
The method for processing a liquid lens according to claim 10, wherein the substrate is a flexible substrate, and after forming a second sealing layer on the substrate for sealing the other end of the substrate through hole, further comprising:

A reinforcing layer is provided on the light incident side of the flexible substrate.
The method for processing a liquid lens according to claim 10, further comprising: after obtaining the single-layer liquid lens:

A plurality of the single-layer liquid lenses are stacked to form a multi-layer liquid lens.