CN105158827B - Electrowetting liquid lens, manufacture method and apply the equipment of this liquid lens - Google Patents

Abstract

The invention discloses a kind of electrowetting liquid lens, manufacture method and apply the equipment of this liquid lens.Electrowetting liquid lens includes container, electrolytic liquid and non-electrolyte liquid, electrolytic liquid and non-electrolyte liquid are placed in described container and form an interface in described container, described container can apply voltage to change the shape at described interface after powering up to described electrolytic liquid, the first coating that the inwall of described container is provided with is weaker than its affinity to described non-electrolyte liquid to the affinity of described electrolytic liquid, and described inwall is additionally provided with the positioning lattice playing the role of positioning described interface.Electrowetting liquid lens of the present invention have employed positioning lattice and is accurately positioned interface, the interface in the range of certain voltage can be made to keep constant, and then reach accurate zoom, digitized zoom, and can solve the problem that the problem that big drop driving voltage is big, focal length change scope is little.

Description

Electrowetting liquid lens, manufacturing method and equipment using the liquid lens

technical field

The invention relates to the technical field of optical lenses, in particular to an electrowetting liquid lens, a manufacturing method and a device using the liquid lens.

Background technique

Variable focus lenses are widely used in integrated imaging devices such as mobile phones, cameras, and microscopes. The traditional zoom lens is composed of multiple lenses, and a mechanical device is used to adjust the relative position of the lenses to achieve the purpose of zooming. Therefore, complex structures, high energy consumption, and easy wear and tear have become the main disadvantages of traditional zoom systems. In order to overcome the above shortcomings, liquid zoom is a good way. There are three ways to realize liquid zoom: (1) Change the internal refractive index of the variable focus liquid lens, and use physical and chemical methods to change the internal parameters such as liquid density and transmittance; (2) ) Change the curvature of the liquid surface, pressurize the liquid surface, change the radius of curvature of the cavity surface, and realize continuous zooming; (3) Based on the electrowetting effect, change the liquid distribution inside the liquid lens to realize the overall deformation of the lens for focusing. Electrowetting variable focus liquid lens has the advantages of simple structure, low cost, low power consumption, long life, easy realization of array structure and integration, fast response speed, etc., so more and more people pay attention to it.

In recent years, many foreign scientific research institutions have made great achievements in electrowetting variable-focus liquid lenses. In the prior art, the main disadvantages of the electrowetting variable focus liquid lens are concentrated in the following points: First, the ordinary tubular liquid lens can only change the focal length, the optical axis is unstable, the focal length cannot be precisely determined, and it is not easy to manufacture and carry out digital Control; Second, the driving voltage of the liquid lens using a large droplet is large and the focal length variation range is small.

Contents of the invention

The technical problem to be solved by the present invention is to provide an electrowetting liquid lens with stable optical axis, precise focal length determination, low driving voltage and large focal length variation range and equipment using the liquid lens.

The technical problem to be solved by the present invention is also to provide a simple and easy-to-operate method for manufacturing an electrowetting liquid lens.

The technical solution adopted by the present invention to solve the problems of the technologies described above is:

The present invention provides an electrowetting liquid lens, comprising: a container, an electrolyte liquid and a non-electrolyte liquid, the electrolyte liquid and the non-electrolyte liquid are accommodated in the container and form an interface in the container, and the container adds After electrification, a voltage can be applied to the electrolyte liquid to change the shape of the interface, and the inner wall of the container is provided with a first coating, the affinity of the first coating to the electrolyte liquid is weaker than that of the electrolyte liquid. In order to improve the affinity of the non-electrolyte liquid, the inner wall is also provided with a positioning lattice for positioning the interface.

As a further improvement of the above technical solution, a positioning layer is provided between the inner wall and the first coating, and the positioning layer is provided with an annular positioning wall, and the positioning lattice is formed between adjacent positioning walls.

As a further improvement of the above technical solution, a conductive layer is provided between the inner wall and the positioning layer.

As a further improvement of the above technical solution, the container includes a conductive cover plate, a conductive substrate, and a cavity tube placed between the conductive cover plate and the conductive substrate, and the conductive layer and the positioning layer are placed in the cavity tube between the wall and the first coat.

As a further improvement of the above technical solution, the first coating is coated with an insulating and hydrophobic material.

As a further improvement of the above technical solution, the conductive layer includes at least two electrodes separated along the axis of the container.

As a further improvement of the above technical solution, the positioning layer is a micron structure formed by a photolithography process.

The invention provides a method for manufacturing an electrowetting liquid lens, comprising: dipping the surface of a cavity tube with photoresist, and forming a positioning layer through photolithography; coating a conductive layer on the inner surface of the positioning layer; The surface of the conductive layer is coated with an insulating and hydrophobic layer; the cavity tube is bonded to the substrate; the electrolyte liquid and the non-electrolyte liquid are successively injected into the cavity tube until it is filled; the upper opening of the cavity tube is sealed with a cover plate .

The present invention provides a mobile phone, which includes the above-mentioned electrowetting liquid lens.

The present invention also provides a digital camera, which includes the above-mentioned electrowetting liquid lens.

The beneficial effects of the present invention are:

The electrowetting liquid lens of the present invention uses a positioning grid to precisely position the interface, which can keep the interface unchanged within a certain voltage range, thereby achieving precise zooming and digital zooming, and can solve the problem of large droplet driving voltage and focal length change A small problem.

The device adopting the electrowetting liquid lens of the present invention can also achieve precise and digital zoom effect, and has small driving voltage and large focal length change range.

The manufacturing method of the electrowetting liquid lens of the present invention adopts the manufacturing principle of photolithography, can accurately build the positioning wall, ensures the positioning accuracy of the positioning grid, and is easy to manufacture.

Description of drawings

Fig. 1 is a schematic structural view of the first embodiment of the electrowetting liquid lens of the present invention;

Fig. 2 is a schematic diagram of electrode distribution of the first embodiment of the electrowetting liquid lens of the present invention;

Fig. 3 is a schematic structural diagram of the second embodiment of the electrowetting liquid lens of the present invention.

detailed description

The idea, specific structure and technical effects of the present invention will be clearly and completely described below in conjunction with the embodiments and accompanying drawings, so as to fully understand the purpose, features and effects of the present invention. Apparently, the described embodiments are only some of the embodiments of the present invention, rather than all of them. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative efforts belong to The protection scope of the present invention. In addition, all the connection/connection relationships involved in the patent do not simply refer to the direct connection of components, but mean that a better connection structure can be formed by adding or reducing connection accessories according to specific implementation conditions. The various technical features in the present invention can be combined interactively on the premise of not conflicting with each other.

Fig. 1 and Fig. 2 show the specific structure of the first embodiment of the electrowetting liquid lens of the present invention. Please refer to FIG. 1 and FIG. 2 together. The electrowetting liquid lens of the present invention includes a container 11, an electrolyte liquid 12, and a non-electrolyte liquid 13. The electrolyte liquid 12 and the non-electrolyte liquid 13 are contained in the container 11 and placed in the An interface 14 is formed in the container 11 , and after the container 11 is powered on, a voltage can be applied to the electrolyte liquid 12 to change the shape of the interface 14 . The non-electrolyte liquid 13 may be an alkane like hexadecane or silicone oil or a mixture thereof, and the electrolyte liquid 12 may be water or a salt solution such as an aqueous sodium chloride solution.

The container 11 includes a conductive cover plate 11a, a conductive substrate 11b, and a cavity pipe 11c placed between the conductive cover plate 11a and the conductive substrate 11b, the inner wall of the cavity pipe 11c is provided with a first coating 15, the The affinity of the first coating 15 to the electrolyte liquid 12 is weaker than its affinity to the non-electrolyte liquid 13, and a conductive layer 17 and positioning layer 16, the positioning layer 16 refers to the positioning wall 16a arranged around the inner wall of the cavity pipe 11c, and a concave shape is formed between adjacent positioning walls 16a to position the interface 14 As a positioning grid, the first coating 15 is coated with an insulating hydrophobic material.

The material of the cavity tube 11c in this embodiment is preferably but not limited to glass, and may also be metal or flexible polymer, such as PET, PI, PDMS, PMMA and the like.

The first coating 15 is a single-layer insulating hydrophobic material, preferably AF1600, AF1601, AF1600X, Hyflon, Cytop or fluorinated polyimide and other surface hydrophobic insulating film materials; in different embodiments, the first The coating 15 can also be divided into two layers: an insulating layer and a hydrophobic layer, that is, a layer of dielectric material such as a silicon oxide layer or a silicon nitride layer is coated on the conductive layer 17, with a thickness of 10-500nm to form an insulating layer. ; Then coat a layer of 10-100nm hydrophobic material to form a hydrophobic layer. Of course, when the coated material meets the requirements of hydrophobicity and insulation at the same time, it can be directly coated to form an insulating hydrophobic layer.

The positioning grid 18 formed by micromachining corresponds to a voltage adjustment range. When the adjustment voltage is within this range, since the positioning grid 18 is on the order of microns, we can consider that the shape of the interface 14 remains unchanged at this time, thereby achieving the control of the liquid interface 14. Positioning function, so that digital zoom can be accurately realized.

The conductive layer 17 includes at least two electrodes separated along the axial direction of the container 11. In this embodiment, the conductive layer 17 is divided into four electrodes: a first electrode 17a, a second electrode 17b, a third electrode 17c and a fourth electrode 17a. Electrode 17d. The two incompatible liquids in the cavity tube 11c form the surface shape as the first interface state 14a due to the difference in surface tension. After applying voltage, the voltage changes the interfacial tension between the two phases of oil and water, resulting in the shape of the interface 14 Change to the second interface state 14b. When the height of the positioning wall 16a is high, the liquid level remains unchanged after the voltage is removed. At this time, if the potential of the first electrode 17a is the highest, the interface 14 will deviate toward the direction of the first electrode 17a, that is, using four electrodes Different potentials cause the interface to deviate in different directions, causing the interface to return to the first interface state 14a.

Fig. 3 shows the specific structure of the second embodiment of the electrowetting liquid lens of the present invention. The difference between this embodiment and the first embodiment is that the metal tube 21c is used instead of the glass tube, so that there is no need to coat the metal tube 21c with a conductive layer, and the first coating 25 is directly coated on the The surface of the metal pipe 21c is sufficient. Of course, in this embodiment, positioning walls 26a also need to be provided on the metal pipe 21c to form the positioning grid 28 .

The manufacturing method of the electrowetting liquid lens of the present invention, taking the glass tube as an example, is as follows:

S1. Clean and dry the glass tube with an inner diameter of 0.1-10 mm, an outer diameter of 0.2-20 mm, and a height of 1-100 mm.

S2. Dip the clean glass tube into the photoresist to form a photoresist film with a thickness of 1-10 microns on the inner tube wall, and the height of the positioning wall is realized by the different viscosities of the photoresist. The photoresist-coated glass tube was then dried at 65-95°C for 10-30 minutes and cooled to room temperature. Put the glass tube horizontally and contact with the mask plate and expose it to ultraviolet radiation. After the exposure, heat the quartz glass tube at 65-95 degrees Celsius for 10-30 minutes, and finally put the glass tube that has completed the above process in the developer solution. Developing in the middle, the developer dissolves the unexposed area, and the remaining positioning wall structure remains on the inner wall of the glass tube. The width of the wall is preferably 1-100 microns, and the distance between the walls is 1-100 microns.

S3. After the positioning wall is solidified, plate a conductive layer with a thickness of about 10-250 nm on the inner and outer walls of the glass tube as an electrode. It should be noted that there is no conductive layer within a certain distance from the lower end of the glass tube, as shown in Figure 1. Layer 17. In particular, if a metal tube with an inner diameter of 0.1-10 mm and an outer diameter of 0.2-20 mm is used instead of a glass tube, the insulating and hydrophobic layer can be directly coated without making a conductive layer in advance.

S4. Use the dip coating method to immerse the glass tube in the fluoropolymer solution, so that the fluoropolymer forms a hydrophobic insulating layer with a thickness of about 0.5-1.5 um on the inner and outer walls of the glass tube, as shown in Figure 1 First coat 15.

S5. Adhesively and firmly connect the above-mentioned glass tube and the conductive substrate with glue.

S6. Use a pipette gun to inject the electrolyte liquid into the bottom of the lens, and then extract the non-electrolyte liquid to fill the lens.

S7. Glue the device filled with liquid to the conductive glass cover.

Due to its small size, light weight and simple structure, the electrowetting liquid lens of the present invention can be applied in digital cameras, portable computers with built-in cameras or mobile phones, replacing traditional optical zoom components. Of course, the liquid lens of the present invention can be applied to vehicle camera sensors in the industrial field, industrial systems with barcode reading devices, and industrial endoscopes; television internal monitors and surveillance cameras in safe places.

It should be noted that electrowetting is also called electrowetting, and the present invention is also applicable to electrowetting liquid lenses.

The above is a specific description of the preferred implementation of the present invention, but the present invention is not limited to the described embodiments, and those skilled in the art can also make various equivalent deformations or replacements without violating the spirit of the present invention. These equivalent modifications or replacements are all within the scope defined by the claims of the present application.

Claims (10)

1. An electrowetting liquid lens, comprising: a container, an electrolyte liquid and a non-electrolyte liquid, the electrolyte liquid and the non-electrolyte liquid are accommodated in the container and form an interface in the container, after the container is powered A voltage can be applied to the electrolyte liquid to change the shape of the interface, and the inner wall of the container is provided with a first coating, characterized in that the first coating has a weaker affinity for the electrolyte liquid than its For the affinity of the non-electrolyte liquid, the inner wall is also provided with a positioning grid for positioning the interface, and the positioning grid corresponds to a voltage adjustment range. 2. The electrowetting liquid lens according to claim 1, wherein a positioning layer is provided between the inner wall and the first coating, and the positioning layer is provided with an annular positioning wall adjacent to the positioning layer. The spacers are formed between the walls. 3. The electrowetting liquid lens according to claim 2, wherein a conductive layer is provided between the inner wall and the positioning layer. 4. The electrowetting liquid lens according to claim 3, wherein the container comprises a conductive cover, a conductive substrate, and a cavity tube placed between the conductive cover and the conductive substrate, and the conductive A layer and a positioning layer are placed between the inner wall of the lumen tube and the first coating. 5. The electrowetting liquid lens according to any one of claims 1 to 4, characterized in that: the first coating is coated with an insulating hydrophobic material. 6. The electrowetting liquid lens according to claim 3 or 4, wherein the conductive layer comprises at least two electrodes separated along the axis of the container. 7. The electrowetting liquid lens according to claim 2, wherein the positioning layer is a micron structure formed by photolithography. 8. A method of manufacturing an electrowetting liquid lens, comprising: Dip-coating the surface of the cavity tube with photoresist, and forming a positioning layer by photolithography; Coating a conductive layer on the inner surface of the positioning layer; Coating an insulating hydrophobic layer on the surface of the conductive layer; bonding the cavity tube to the substrate; Inject electrolyte liquid and non-electrolyte liquid into the cavity tube successively until it is full; Cover the upper opening of the cavity tube with a cover plate. 9. A mobile phone, characterized by comprising the electrowetting liquid lens according to claim 1. 10. A digital camera, characterized by comprising the electrowetting liquid lens according to claim 1.