Liquid lens, preparation method and driving method thereof

Abstract

The present invention provides a liquid lens, and a preparation method and a driving method thereof. The liquid lens comprises a driving electrode, a first substrate and a second substrate. The driving electrode is provided with a through light hole. The first substrate and the second substrate respectively seal the two ends of the light hole to form a receiving chamber. The first substrate forms a side surface of the inner wall of the receiving chamber and is hydroxylated. The receiving chamber is filled with mutually immiscible polar liquid and non-polar liquid, and a liquid-liquid two-phase interface is formed between the polar liquid and the non-polar liquid. The present invention performs a hydroxylation modification treatment on part of the inner wall of the liquid lens so that it has a strong hydrophilic and oleophobic effect, thereby reducing the aggregation of small droplets of non-polar liquid.

Description

Technical Field

[0001] The invention belongs to the technical field of optical lenses and relates to a liquid lens, a preparation method and a driving method thereof. Background Art

[0002] Electrowetting driven liquid lens has the advantages of fast response, low power consumption, low cost and easy integration, and has a wide range of potential applications in industrial code scanning, machine vision, consumer electronic lenses and other fields. The electrowetting liquid lens is composed of a chamber formed by two transparent glass substrates. Two immiscible liquids in the chamber form a meniscus, and the shape of the meniscus changes under voltage drive to achieve the function of fast zoom. One of the liquids in the chamber is a conductive polar liquid, and the other is a non-conductive non-polar liquid. Due to changes in ambient temperature and liquid movement, part of the non-polar liquid will enter the polar liquid in the form of small droplets and adsorb to the surface of the glass substrate. The small droplets on the surface of the glass substrate will affect the optical properties of the liquid lens. For this type of problem, the optimization method used in the prior art is to adjust the liquid formula to make the two liquids more immiscible, but this method often affects the changes in other parameters such as the refractive index of the liquid.

[0003] Therefore, how to prevent the two liquids in the liquid lens from miscible with each other while maintaining the high refractive index of the liquid has become the current focus of attention. Summary of the invention

[0004] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a liquid lens, a preparation method and a driving method thereof, by hydroxylating a part of the inner cavity wall of the liquid lens to make it have a strong hydrophilic and oleophobic effect, thereby reducing the aggregation of small droplets of non-polar liquid.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] In a first aspect, the present invention provides a liquid lens, comprising a driving electrode, a first substrate and a second substrate, wherein the driving electrode is provided with a through light hole, the first substrate and the second substrate respectively seal both ends of the light hole to form a receiving chamber, and a surface of one side of an inner wall of the receiving chamber formed by the first substrate is hydroxylated;

[0007] The containing chamber is filled with mutually immiscible polar liquid and non-polar liquid, a liquid-liquid two-phase interface is formed between the polar liquid and the non-polar liquid, the polar liquid is close to the first substrate, and the non-polar liquid is close to the second substrate.

[0008] The liquid lens provided by the present invention has a strong hydrophilic and oleophobic effect by performing hydroxylation modification on the surface of a first substrate, thereby reducing the aggregation of small droplets of non-polar liquid and preventing the occurrence of non-polar liquid residue due to the contact between the liquid-liquid two-phase interface between the polar liquid and the non-polar liquid and the first substrate.

[0009] It should be noted that the polar liquid and the non-polar liquid in the liquid lens have different refractive indices. The polar liquid is conductive, while the non-polar liquid is not conductive. In addition, the polar liquid and the non-polar liquid are immiscible with each other. The two phases of liquid remain in contact and form a crescent-shaped liquid-liquid interface. The wettability of the liquid is controlled by applying voltage, causing the meniscus to change.

[0010] The present invention does not impose any specific requirements or special limitations on the selection of polar solutions and non-polar solutions. They can be any two immiscible liquids for liquid lenses known to those skilled in the art. For example, the polar liquid can be water, or ethylene glycol or propylene glycol, and the non-polar liquid can be chlorobenzene, bromobenzene or silicone oil. That is, any other two immiscible liquids that can be used for liquid lenses that have been disclosed in the prior art or not disclosed in the new technology can be used in the present invention, and are not limited to the above liquids.

[0011] As a preferred technical solution of the present invention, the surface roughness of the first substrate after hydroxylation modification is ≤30nm.

[0012] Preferably, the air-water contact angle of the surface of the first substrate after hydroxylation modification is ≤10°.

[0013] Preferably, the light-through hole is any one of cylindrical, truncated cone or inverted truncated cone shapes or a combination of at least two of them, wherein typical but non-limiting combinations are: a combination of cylindrical and truncated cone shapes, a combination of cylindrical and inverted truncated cone shapes, or a combination of truncated cone shapes and inverted truncated cone shapes.

[0014] As a preferred technical solution of the present invention, at least one dielectric insulating layer is disposed on the surfaces of the driving electrode located in the inner cavity of the accommodating chamber and the second substrate respectively.

[0015] Preferably, a hydrophobic layer is further provided on the side of the dielectric insulation layer contacting the polar liquid and / or the non-polar liquid.

[0016] The present invention can effectively prevent the breakdown of the driving electrode by arranging a dielectric insulating layer on the second substrate and the surface of the driving electrode on the side close to the liquid in the accommodating chamber, and can obtain a better electrowetting effect by arranging a hydrophobic layer.

[0017] It should be noted that, in the present invention, the dielectric insulating layer on the surface of the second substrate is in contact with the non-polar liquid only, while the dielectric insulating layer on the surface of the driving electrode can be in contact with both the polar liquid and the non-polar liquid.

[0018] The present invention does not make any specific requirements or special limitations on the selection of materials for the dielectric insulating layer and the hydrophobic layer. They can be any dielectric insulating layer and hydrophobic layer for liquid lenses known to any person skilled in the art. For example, the material of the dielectric insulating layer can be any one of aluminum oxide, tantalum pentoxide, and polyparaxylene; the material of the hydrophobic film can be Cytop, AF1600 or other fluorides. That is, other materials for dielectric insulating layers and hydrophobic layers that can be used for liquid lenses that have been disclosed in the prior art or not disclosed in the new technology can be used in the present invention, and are not limited to the above-mentioned liquids.

[0019] Preferably, the thickness of the dielectric insulating layer is 500 to 5000 nm, for example, it can be 500 nm, 600 nm, 800 nm, 1000 nm, 1200 nm, 1500 nm, 2000 nm, 2500 nm, 3000 nm, 3500 nm, 4000 nm, 4500 nm or 5000 nm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0020] Preferably, the thickness of the hydrophobic layer is 20 to 100 nm, for example, it can be 20 nm, 30 nm, 40 nm, 50 nm, 55 nm, 60 nm, 65 nm, 70 nm, 75 nm, 80 nm, 55 nm, 90 nm, 95 nm or 100 nm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0021] In a second aspect, the present invention provides a method for preparing the liquid lens according to the first aspect, the preparation method comprising:

[0022] (I) providing a driving electrode, a first substrate and a second substrate, and performing a hydroxylation modification treatment on the surface of the first substrate;

[0023] (II) a through light hole is formed on the driving electrode, and the first substrate and the second substrate are respectively covered on both ends of the light hole to form a receiving chamber;

[0024] (III) Injecting a polar liquid and a non-polar liquid into the containing chamber respectively to obtain the liquid lens.

[0025] The present invention performs hydroxylation modification treatment on the surface of the first substrate to make it have a strong hydrophilic and oleophobic effect, thereby reducing the aggregation of small droplets of non-polar liquid.

[0026] As a preferred technical solution of the present invention, in step (I), the hydroxylation modification includes: subjecting the first substrate to plasma etching, acid solution immersion, cleaning and drying in sequence to obtain a modified first substrate.

[0027] As a preferred technical solution of the present invention, the plasma etching adopts oxygen plasma or argon-oxygen plasma.

[0028] Preferably, the plasma etching time is 300 to 600 s, for example, it can be 300 s, 320 s, 330 s, 350 s, 380 s, 400 s, 450 s, 480 s, 500 s, 550 s, 580 s or 600 s, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0029] Preferably, the power of the plasma etching is 200-400 W, for example, it can be 200 W, 220 W, 230 W, 250 W, 260 W, 270 W, 300 W, 320 W, 350 W, 380 W or 400 W, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0030] Preferably, the acid solution soaking includes: soaking the first substrate in a mixed solution of sulfuric acid and hydrogen peroxide.

[0031] Preferably, the cleaning comprises: spraying or rinsing the first substrate with deionized water.

[0032] Preferably, the drying temperature is 60-120°C, for example, it can be 60°C, 70°C, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C or 120°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0033] As a preferred technical solution of the present invention, in step (II), the preparation method further comprises: coating at least one layer of dielectric insulating film on the surface of the inner cavity wall of the accommodating cavity formed by the driving electrode and the second substrate respectively.

[0034] Preferably, the dielectric insulating film is solidified on the surfaces of the driving electrode and the second substrate by using glue.

[0035] Preferably, a hydrophobic film is coated on the surface of the dielectric insulating film on the side in contact with the polar liquid and / or the non-polar liquid.

[0036] As a preferred technical solution of the present invention, in step (III), the polar liquid is close to the first substrate, and the non-polar liquid is close to the second substrate.

[0037] When no voltage is applied to the liquid lens and the liquid lens operates normally, the first substrate is in direct contact with the polar liquid, the second substrate is in contact with the non-polar liquid, and the driving electrode is in contact with both the polar liquid and the non-polar liquid.

[0038] In a third aspect, the present invention provides a method for driving the liquid lens according to the first aspect, the driving method comprising:

[0039] The liquid lens is provided, a voltage is applied to the liquid lens, and the output voltage is adjusted so that the liquid-liquid two-phase interface is bent to be concave or convex, so as to remove residual droplets on the inner wall of the accommodating chamber and realize the initialization of the liquid lens.

[0040] The present invention provides a driving method for a liquid lens, which initializes the liquid lens and drives the liquid-liquid two-phase interface to contact the inner wall of a containing chamber by adjusting the output voltage, thereby absorbing and removing small droplets of non-polar liquid and improving the optical performance of the liquid lens.

[0041] As a preferred technical solution of the present invention, the driving method specifically includes:

[0042] (1) obtaining the liquid lens, wherein a liquid-liquid two-phase interface formed between the polar liquid and the non-polar liquid in the containing chamber is in a concave state curved toward a direction close to the second substrate;

[0043] (2) applying a voltage to the driving electrode and gradually increasing the output voltage to a preset voltage value, so that the liquid-liquid two-phase interface bends toward the first substrate to form a convex state, and contacts the surface of the first substrate to absorb the non-polar liquid remaining on the surface of the first substrate;

[0044] (3) Then, the output voltage is gradually reduced to zero voltage, and the liquid-liquid two-phase interface bends toward the direction close to the second substrate to form a concave state, thereby completing initialization;

[0045] (4) A voltage is applied to the driving electrode until the output voltage is the working voltage, and the liquid-liquid two-phase interface bends toward the first substrate to form a convex state, thereby driving the liquid lens to work.

[0046] The polar liquid and the non-polar liquid in the liquid lens are immiscible with each other. The two phases of liquid remain in contact and form a meniscus-shaped liquid-liquid interface. The wettability of the liquid is controlled by applying voltage, causing the meniscus to change. When the applied voltage is increased, the meniscus-shaped liquid-liquid interface gradually bulges toward the direction close to the polar liquid to form a convex liquid surface. When the applied voltage is reduced, the meniscus-shaped liquid-liquid interface gradually returns to a concave liquid surface close to the non-polar liquid.

[0047] Preferably, the preset voltage value is greater than the operating voltage.

[0048] Preferably, the operating voltage is 80-95% of the preset voltage value, for example, it can be 80%, 82%, 83%, 85%, 86%, 86%, 90%, 92%, 94% or 95%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0049] During normal operation of the liquid lens of the present invention, an operating voltage is applied to the driving electrode, and the meniscus-shaped liquid-liquid interface is in a convex state (convex liquid surface). When the voltage is increased to the maximum operating voltage and overloaded to a certain voltage value, the highest point of the liquid-liquid interface gradually moves toward the first substrate and contacts the hydroxylated inner surface of the first substrate to adsorb and remove small droplets of non-polar liquid, thereby improving the optical performance of the liquid lens.

[0050] The numerical range described in the present invention not only includes the point values ​​listed above, but also includes any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0051] Compared with the prior art, the present invention has the following beneficial effects:

[0052] (1) The present invention provides a liquid lens, a preparation method and a driving method thereof, wherein the surface of the first substrate is subjected to a hydroxylation modification treatment to make it have a strong hydrophilic and oleophobic effect, thereby reducing the aggregation of small droplets of non-polar liquid on the surface of the first substrate, and preventing the problem of non-polar liquid residue due to the contact between the liquid-liquid two-phase interface and the surface of the first substrate during the initialization process;

[0053] (2) The present invention initializes the liquid lens and uses an overload voltage to drive the liquid-liquid two-phase interface to contact the inner surface of the first substrate, thereby adsorbing and removing small droplets of non-polar liquid and improving the optical performance of the liquid lens. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 A schematic diagram of a polar liquid and a non-polar liquid when no voltage is applied to a liquid lens provided by a specific embodiment of the present invention;

[0055] Figure 2 A schematic diagram of a polar liquid and a non-polar liquid during the initialization process of a liquid lens provided by a specific embodiment of the present invention;

[0056] Figure 3 A schematic diagram of polar liquid and non-polar liquid when a liquid lens provided in a specific embodiment of the present invention is working normally.

[0057] Among them, 1-first substrate; 2-second substrate; 3-driving electrode; 4-polar liquid; 5-non-polar liquid; 6-liquid-liquid two-phase interface. DETAILED DESCRIPTION

[0058] It should be understood that, in the description of the present invention, the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0059] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0060] In one embodiment, the present invention provides a liquid lens, such as Figure 1 As shown, it includes a driving electrode 3, a first substrate 1 and a second substrate 2, the driving electrode 3 is provided with a through light hole, the first substrate 1 and the second substrate 2 respectively seal the two ends of the light hole to form a receiving chamber, and the first substrate 1 forms a side surface of the inner wall of the receiving chamber and is hydroxylated;

[0061] The containing chamber is filled with mutually immiscible polar liquid 4 and non-polar liquid 5 , a liquid-liquid two-phase interface 6 is formed between the polar liquid 4 and the non-polar liquid 5 , the polar liquid 4 is close to the first substrate 1 , and the non-polar liquid 5 is close to the second substrate 2 .

[0062] The polar liquid 4 and the non-polar liquid 5 in the liquid lens have different refractive indices. The polar liquid 4 is conductive, while the non-polar liquid 5 is non-conductive. The polar liquid 4 and the non-polar liquid 5 are immiscible with each other. The two phases of liquid remain in contact and form a meniscus-shaped liquid-liquid two-phase interface 6. The wettability of the liquid is controlled by applying voltage, thereby causing the meniscus to change.

[0063] The present invention does not limit the material of the driving electrode 3 , and it can be any material known to those skilled in the art, for example, any one of metal iron, iron alloy, metal copper, copper alloy, metal aluminum, and aluminum alloy.

[0064] In some embodiments, the first substrate 1 and the second substrate 2 of the present invention are respectively any one of indium tin oxide glass, quartz glass or organic glass.

[0065] The present invention does not impose any specific requirements or special limitations on the selection of polar solutions and non-polar solutions. They can be any two immiscible liquids for liquid lenses known to those skilled in the art. For example, the polar liquid 4 can be water, or ethylene glycol or propylene glycol, and the non-polar liquid 5 can be chlorobenzene, bromobenzene or silicone oil. That is, any other two immiscible liquids that can be used for liquid lenses that have been disclosed in the prior art or not disclosed in the new technology can be used in the present invention, and are not limited to the above-mentioned liquids.

[0066] In some embodiments, the surface roughness of the first substrate 1 after hydroxylation modification is ≤30 nm.

[0067] The air-water contact angle of the surface of the first substrate 1 after hydroxylation modification is ≤10°. After hydroxylation modification, the air-water contact angle of the first substrate 1 of the present invention is reduced, showing a strong hydrophilic and oleophobic effect, and reducing the adhesion of the non-polar liquid 5.

[0068] The light-through hole is any one of cylindrical, truncated cone or inverted truncated cone shapes or a combination of at least two of them. Typical but non-limiting combinations are: a combination of cylindrical and truncated cone, a combination of cylindrical and inverted truncated cone, or a combination of truncated cone and inverted truncated cone. The present invention exemplarily provides the following specific structure of the light-through hole: the light-through hole is composed of a cylindrical first through hole and a truncated cone second through hole arranged in sequence along the axial direction, or the light-through hole is composed of a cylindrical first through hole and an inverted truncated cone second through hole arranged in sequence along the axial direction, or the light-through hole is composed of a truncated cone first through hole and an inverted truncated cone second through hole arranged in sequence along the axial direction.

[0069] In some embodiments, at least one dielectric insulating layer is disposed on the surfaces of the driving electrode 3 located in the inner cavity of the accommodating chamber and the second substrate 2 .

[0070] In some embodiments, a hydrophobic layer is further provided on the side of the dielectric insulating layer that contacts the polar liquid 4 and / or the non-polar liquid 5 .

[0071] The present invention can effectively prevent the breakdown of the driving electrode 3 by arranging a dielectric insulating layer on the second substrate 2 and the surface of the driving electrode 3 on the side close to the liquid in the accommodating chamber, and can obtain a better electrowetting effect by arranging a hydrophobic layer.

[0072] In some embodiments, the thickness of the dielectric insulating layer is 500 to 5000 nm, and the thickness of the hydrophobic layer is 20 to 100 nm. The present invention does not make specific requirements or special limitations on the selection of materials for the dielectric insulating layer and the hydrophobic layer. They can be any dielectric insulating layer and hydrophobic layer known to any person skilled in the art. For example, the material of the dielectric insulating layer can be any one of aluminum oxide, tantalum pentoxide, and polyparaxylene; the material of the hydrophobic film can be Cytop, AF1600 or other fluorides, that is, other materials for dielectric insulating layers and hydrophobic layers that can be used for liquid lenses that have been disclosed in the prior art or not disclosed in the new technology can be used in the present invention, not limited to the above-mentioned liquids.

[0073] In another specific embodiment, the present invention provides a method for preparing the liquid lens of a specific embodiment, the preparation method comprising:

[0074] (I) providing a driving electrode 3, a first substrate 1 and a second substrate 2, and performing a hydroxylation modification treatment on the surface of the first substrate 1;

[0075] (II) a through light hole is formed on the driving electrode 3, and the first substrate 1 and the second substrate 2 are respectively covered at both ends of the light hole to form a receiving chamber;

[0076] (III) Injecting the polar liquid 4 and the non-polar liquid 5 into the containing chamber respectively to obtain the liquid lens.

[0077] The present invention performs hydroxylation modification on the surface of the first substrate 1 to make it have a strong hydrophilic and oleophobic effect, thereby reducing the aggregation of small droplets of the non-polar liquid 5.

[0078] In some embodiments, in step (I), the hydroxylation modification includes: sequentially subjecting the first substrate 1 to plasma etching, acid solution immersion, cleaning and drying to obtain a modified first substrate 1 .

[0079] The plasma etching adopts oxygen plasma or argon-oxygen plasma, the plasma etching time is 300-600s, and the plasma etching power is 200-400W.

[0080] In some embodiments, the acid solution soaking includes: soaking the first substrate 1 in a mixed solution of sulfuric acid and hydrogen peroxide.

[0081] In some embodiments, the cleaning includes: spraying or rinsing the first substrate 1 with deionized water.

[0082] In some embodiments, the drying temperature is 60-120°C.

[0083] In some embodiments, in step (II), the preparation method further comprises: coating at least one layer of dielectric insulating film on the surface of the inner wall of the receiving chamber formed by the driving electrode 3 and the second substrate 2, respectively. The dielectric insulating film is cured on the surface of the driving electrode 3 and the second substrate 2 by using glue.

[0084] A hydrophobic film is coated on the surface of the dielectric insulating film on the side contacting the polar liquid 4 and / or the non-polar liquid 5 .

[0085] In some embodiments, in step (III), the polar liquid 4 is close to the first substrate 1, and the non-polar liquid 5 is close to the second substrate 2. When no voltage is applied to the liquid lens and the liquid lens operates normally, the first substrate 1 is in direct contact with the polar liquid 4, the second substrate 2 is in contact with the non-polar liquid 5, and the driving electrode 3 is in contact with both the polar liquid 4 and the non-polar liquid 5.

[0086] In another specific embodiment, the present invention provides a driving method of the liquid lens of a specific embodiment, and the driving method specifically includes:

[0087] (1) Obtain the liquid lens, such as Figure 1 As shown, the liquid-liquid two-phase interface 6 formed between the polar liquid 4 and the non-polar liquid 5 in the containing chamber is in a concave state bent toward the direction close to the second substrate 2;

[0088] (2) Figure 2 As shown, a voltage is applied to the driving electrode 3, and the output voltage is gradually increased to a preset voltage value, so that the liquid-liquid two-phase interface 6 is bent toward the direction close to the first substrate 1 to form a convex state, and contacts the surface of the first substrate 1, and absorbs the non-polar liquid 5 remaining on the surface of the first substrate 1;

[0089] (3) Then, the output voltage is gradually reduced to zero voltage, and the liquid-liquid two-phase interface 6 bends toward the direction close to the second substrate 2 to form a concave state, completing the initialization;

[0090] (4) Figure 3 As shown, a voltage is applied to the driving electrode 3 until the output voltage is the working voltage, and the liquid-liquid two-phase interface 6 bends toward the direction close to the first substrate 1 to form a convex state, so as to drive the liquid lens to work.

[0091] The driving method of the liquid lens provided by the present invention initializes the liquid lens, drives the liquid-liquid two-phase interface 6 to contact the inner wall of the accommodating chamber by adjusting the output voltage, absorbs and removes small droplets of non-polar liquid 5, and improves the optical performance of the liquid lens. The polar liquid 4 and the non-polar liquid 5 in the liquid lens are mutually immiscible, the two phases of liquid keep in contact, and form a meniscus-shaped liquid-liquid two-phase interface 6, and the wettability of the liquid is controlled by applying a voltage to cause the meniscus to change. When the applied voltage is increased, the meniscus-shaped liquid-liquid two-phase interface 6 gradually bulges toward the direction close to the polar liquid 4 to form a convex liquid surface, and when the applied voltage is reduced, the meniscus-shaped liquid-liquid two-phase interface 6 gradually recovers to the direction close to the non-polar liquid 5 to be concave to form a concave liquid surface.

[0092] The preset voltage value is greater than the working voltage and is overloaded by a certain voltage value. Specifically, the working voltage is 80-95% of the preset voltage value. During normal operation of the liquid lens of the present invention, a working voltage is applied to the driving electrode 3, and the meniscus-shaped liquid-liquid two-phase interface 6 is in a convex state. When the overload voltage is increased, the highest point of the liquid-liquid two-phase interface 6 gradually moves toward the first substrate 1 and contacts the hydroxylated inner surface of the first substrate 1 to adsorb and remove small droplets of the non-polar liquid 5, thereby improving the optical performance of the liquid lens.

[0093] Example 1

[0094] This embodiment provides a liquid lens, including a driving electrode 3, a first substrate 1 and a second substrate 2, wherein the driving electrode 3 is provided with a through light hole, the first substrate 1 and the second substrate 2 respectively seal both ends of the light hole to form a receiving chamber, and the first substrate 1 is hydroxylated and modified, and is specifically prepared by the following method:

[0095] (1) providing a driving electrode 3, a first substrate 1 and a second substrate 2;

[0096] (2) Plasma etching, acid immersion, cleaning and drying are performed on the first substrate 1 in sequence to obtain a hydroxylated first substrate 1, wherein the plasma etching conditions are: using oxygen plasma, the etching time is 480s, and the power is 300W; the acid immersion conditions are: using a mixed solution of sulfuric acid and hydrogen peroxide to immerse the first substrate 1; the cleaning conditions are: using deionized water to rinse the first substrate 1; and the drying temperature is 90°C;

[0097] (3) a through light hole is formed on the driving electrode 3, a dielectric insulating film is coated on the inner surface of the driving electrode 3 to form a dielectric insulating layer, and a hydrophobic film is coated on the upper surface of the dielectric insulating layer to form a hydrophobic layer;

[0098] (4) coating a dielectric insulating film on the inner surface of the second substrate 2 to form a dielectric insulating layer, and coating a hydrophobic film on the upper surface of the dielectric insulating layer to form a hydrophobic layer, and respectively covering the modified first substrate 1 and the second substrate 2 at both ends of the light-through hole to form a receiving chamber;

[0099] (5) Injecting mutually immiscible polar liquid 4 and non-polar liquid 5 into the containing chamber respectively, and forming a liquid-liquid interface 6 between the polar liquid 4 and the non-polar liquid 5, the liquid-liquid interface 6 is in a concave state bent toward the direction close to the second substrate 2, thereby obtaining a liquid lens.

[0100] In this embodiment, the air-water contact angle of the surface of the first substrate 1 after hydroxylation modification is 3°; the thickness of the dielectric insulating layer on the surface of the driving electrode 3 and the second substrate 2 is 120 nm, and the thickness of the hydrophobic layer is 80 nm.

[0101] The liquid lens of this embodiment was placed in an oven at 85°C for 10 hours, and then taken out of the oven and left to stand for 1 day. The observation result was that a small amount of small droplets of non-polar liquid 5 appeared on the surface of the first substrate 1 located on the inner wall of the receiving chamber. The liquid lens of this embodiment was tested for modulation transfer function. The edge and center resolution of the prepared liquid lens were good, and it had good optical performance.

[0102] Comparative Example 1

[0103] This comparative example provides a liquid lens, which is different from Example 1 in that the first substrate 1 is not hydroxylated, and the other process parameters and operating conditions are the same as those of Example 1.

[0104] The liquid lens of this comparative example was placed in an oven at 85°C for 10 hours, and then taken out of the oven and left to stand for 1 day, and the observation results were obtained: a small amount of non-polar liquid 5 droplets appeared on the surface of the first substrate 1 located on the inner wall of the accommodating chamber. The liquid lens of this comparative example was tested for modulation transfer function, and the prepared liquid lens had good resolution at the edge and center, and had good optical performance.

[0105] Example 2

[0106] This embodiment drives the liquid lens in Embodiment 1, specifically using the following method:

[0107] First, a voltage is applied to the driving electrode 3, and the output voltage is gradually increased to a preset voltage value, which is greater than the maximum value of the working voltage of the liquid lens, and is overloaded by a certain voltage value, so that the liquid-liquid two-phase interface 6 is bent toward the direction close to the first substrate 1 to form a convex state, and contacts the surface of the first substrate 1, and absorbs the non-polar liquid 5 remaining on the surface of the first substrate 1;

[0108] Then, the output voltage is gradually reduced to zero voltage, and the liquid-liquid two-phase interface 6 bends toward the direction close to the second substrate 2 to form a concave state, thereby completing the initialization.

[0109] After initialization, a voltage is applied to the driving electrode 3 until the output voltage is the working voltage, and the liquid-liquid two-phase interface 6 bends toward the first substrate 1 to form a convex state, but does not contact the first substrate 1, so as to drive the liquid lens to work.

[0110] After driving, most of the small droplets of non-polar liquid 5 on the inner surface of the first substrate 1 are adsorbed, and a small amount of small droplets of non-polar liquid 5 remain on the edge. The optical performance of the liquid lens is basically unchanged, the central resolution is unchanged, and the edge resolution is slightly reduced.

[0111] Comparative Example 2

[0112] This embodiment drives the liquid lens in Embodiment 1, and the difference from Embodiment 2 is that the liquid lens is not initialized, and a working voltage is directly applied to the driving electrode 3 to drive the liquid lens to work.

[0113] After being driven, there are a small amount of non-polar liquid 5 droplets on the inner surface of the first substrate 1 of the liquid lens (part of the surface of the first substrate 1 located in the inner cavity of the accommodating chamber), which has a certain influence on the optical performance of the liquid lens, and the center and edge resolution of the liquid lens is slightly reduced.

[0114] Example 3

[0115] This embodiment drives the liquid lens in Comparative Example 1, specifically using the following method:

[0116] First, a voltage is applied to the driving electrode 3, and the output voltage is gradually increased to a preset voltage value, which is greater than the maximum value of the working voltage of the liquid lens, and is overloaded by a certain voltage value, so that the liquid-liquid two-phase interface 6 is bent toward the direction close to the first substrate 1 to form a convex state, and contacts the surface of the first substrate 1, and absorbs the non-polar liquid 5 remaining on the surface of the first substrate 1;

[0117] Then, the output voltage is gradually reduced to zero voltage, and the liquid-liquid two-phase interface 6 bends toward the direction close to the second substrate 2 to form a concave state, thereby completing the initialization.

[0118] After initialization, a voltage is applied to the driving electrode 3 until the output voltage is the working voltage, and the liquid-liquid two-phase interface 6 bends toward the first substrate 1 to form a convex state, but does not contact the first substrate 1, so as to drive the liquid lens to work.

[0119] After being driven, a large amount of non-polar liquid 5 remains on the inner surface of the first substrate 1 (part of the surface of the first substrate 1 located in the inner cavity of the accommodating chamber), which seriously affects the optical performance of the liquid lens and seriously reduces the resolution of the center and edge of the liquid lens.

[0120] Comparative Example 3

[0121] This embodiment drives the liquid lens in comparative example 1, and the difference from embodiment 3 is that the liquid lens is not initialized, and a working voltage is directly applied to the driving electrode 3 to drive the liquid lens to work.

[0122] After being driven, there are a small amount of non-polar liquid 5 droplets on the inner surface of the first substrate 1 (part of the surface of the first substrate 1 located in the inner cavity of the accommodating chamber), which has a certain influence on the optical performance of the liquid lens, and the center and edge resolution are slightly reduced.

[0123] In the driving method provided by the present invention, the liquid lens is initialized, a voltage is applied to the driving electrode 3, the liquid-liquid two-phase interface 6 is deformed from a concave state (concave liquid surface) to a plane state (horizontal liquid surface), and then to a convex state (convex liquid surface), the voltage is continuously applied to the maximum value of the normal working voltage, and a certain voltage value is overloaded, the convex state of the liquid-liquid two-phase interface 6 touches the inner surface of the first substrate 1, and the small droplets on the first substrate 1 are adsorbed and removed. Since the surface of the first substrate 1 is modified by hydroxylation and exhibits a strong hydrophilic and oleophobic effect, when the voltage is gradually reduced to zero voltage, the non-polar liquid 5 will not remain on the inner surface of the first glass, but will all be restored to the initial concave state (concave liquid surface), so that the small droplets on the inner surface of the first substrate 1 are removed.

[0124] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

[0125] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

Claims

1. A method for driving a liquid lens, characterized in that: The driving method is performed using a liquid lens; The liquid lens comprises a driving electrode, a first substrate and a second substrate, wherein the driving electrode is provided with a through light hole, the first substrate and the second substrate respectively seal two ends of the light hole to form a receiving chamber, and the first substrate forms a side surface of an inner wall of the receiving chamber and is hydroxylated; The containing chamber is filled with a polar liquid and a non-polar liquid that are immiscible with each other, a liquid-liquid two-phase interface is formed between the polar liquid and the non-polar liquid, the polar liquid is close to the first substrate, and the non-polar liquid is close to the second substrate; The driving method comprises: (1) obtaining the liquid lens, wherein a liquid-liquid two-phase interface formed between the polar liquid and the non-polar liquid in the containing chamber is in a concave state curved toward a direction close to the second substrate; (2) applying a voltage to the driving electrode and gradually increasing the output voltage to a preset voltage value, so that the liquid-liquid two-phase interface bends toward the first substrate to form a convex state, and contacts the surface of the first substrate to absorb the non-polar liquid remaining on the surface of the first substrate; (3) Then, the output voltage is gradually reduced to zero voltage, and the liquid-liquid two-phase interface bends toward the direction close to the second substrate to form a concave state, thereby completing initialization; (4) A voltage is applied to the driving electrode until the output voltage is the working voltage, and the liquid-liquid two-phase interface bends toward the first substrate to form a convex state, thereby driving the liquid lens to work.

2. The driving method according to claim 1, characterized in that: The surface roughness of the first substrate after hydroxylation modification is ≤30nm.

3. The driving method according to claim 1, characterized in that: The air-water contact angle of the surface of the first substrate after the hydroxylation modification is ≤10°.

4. The driving method according to claim 1, characterized in that: The light-through hole is in any one of a cylindrical, truncated cone or inverted truncated cone shape or a combination of at least two of them.

5. The driving method according to claim 1, characterized in that: The surfaces of the driving electrode located in the inner cavity of the accommodating chamber and the second substrate are respectively provided with at least one dielectric insulating layer.

6. The driving method according to claim 5, characterized in that: A hydrophobic layer is also provided on the side of the dielectric insulating layer that contacts the polar liquid and / or the non-polar liquid.

7. The driving method according to claim 5, characterized in that: The thickness of the dielectric insulation layer is 500-5000 nm.

8. The driving method according to claim 6, characterized in that: The thickness of the hydrophobic layer is 20-100 nm.

9. The driving method according to claim 1, characterized in that: The liquid lens is prepared by the following preparation method, which comprises: (I) providing a driving electrode, a first substrate and a second substrate, and performing a hydroxylation modification treatment on the surface of the first substrate; (II) a through light hole is formed on the driving electrode, and the first substrate and the second substrate are respectively covered on both ends of the light hole to form a receiving chamber; (III) Injecting a polar liquid and a non-polar liquid into the containing chamber respectively to obtain the liquid lens.

10. The driving method according to claim 9, characterized in that: In step (I), the hydroxylation modification includes: subjecting the first substrate to plasma etching, acid solution immersion, cleaning and drying in sequence to obtain a modified first substrate.

11. The driving method according to claim 10, characterized in that: The plasma etching adopts oxygen plasma or argon-oxygen plasma.

12. The driving method according to claim 10, characterized in that: The plasma etching time is 300 to 600 seconds.

13. The driving method according to claim 10, characterized in that: The power of the plasma etching is 200-400W.

14. The driving method according to claim 10, characterized in that: The acid solution soaking includes: soaking the first substrate in a mixed solution of sulfuric acid and hydrogen peroxide.

15. The driving method according to claim 10, characterized in that: The cleaning includes: spraying or rinsing the first substrate with deionized water.

16. The driving method according to claim 10, characterized in that: The drying temperature is 60-120°C.

17. The driving method according to claim 9, characterized in that: In step (II), the preparation method further comprises: coating at least one layer of dielectric insulating film on the surfaces of the inner cavity wall of the accommodation cavity formed by the driving electrode and the second substrate respectively.

18. The driving method according to claim 17, characterized in that: The dielectric insulating film is solidified on the surfaces of the driving electrode and the second substrate by using glue.

19. The driving method according to claim 17, characterized in that: A hydrophobic film is coated on the surface of the dielectric insulating film at one side contacting the polar liquid and / or the non-polar liquid.

20. The driving method according to claim 9, characterized in that: In step (III), the polar liquid is close to the first substrate, and the non-polar liquid is close to the second substrate.

21. The driving method according to claim 1, characterized in that: The preset voltage value is greater than the maximum value of the operating voltage.

22. The driving method according to claim 1, characterized in that: The operating voltage is 80-95% of the preset voltage value.

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