Device and method for regulating and controlling liquid lens through electric field and sample observation method

Abstract

The invention belongs to the technical field of liquid lenses, and particularly relates to a device and a method for regulating and controlling a liquid lens through an electric field and a sample observation method.The device comprises a transparent conductive substrate electrode, the surface of the transparent conductive substrate electrode is covered with a transparent insulating film, and an annular channel is formed in the transparent insulating film; a plurality of discharge needle points which are transversely arranged are symmetrically distributed in the circumferential direction of the channel, insulating liquid drops are dropwise added to the channel, and a conductive sample rod is arranged above the insulating liquid drops; the plurality of discharge needle tips are used for providing a uniform transverse electric field for the insulating liquid drops, so that positive charges are distributed around the insulating liquid drops, and a local electric field formed in the channel is used for limiting the insulating liquid drops; the electric field action on the liquid drops is regulated and controlled through the transverse electric field, the transparent conductive substrate electrode and the sample rod, and then the forms of the liquid drops are regulated and controlled. The transverse electric field is generated through discharge of the needle tip and directly acts on the charged liquid drop, accurate control over the shape and curvature of the liquid drop is achieved, and the device is simple, low in cost and convenient to integrate and apply on a large scale.

Description

Technical Field

[0001] The present invention belongs to the technical field of liquid lenses, and in particular relates to a device and method for regulating a liquid lens by an electric field, and a sample observation method. Background Art

[0002] As an emerging optical element, liquid lenses are gradually being widely used in the fields of microscopic imaging, camera systems, mobile phone cameras, etc., due to their advantages such as variable curvature, lightness, and ease of manufacturing. Traditional solid lenses cannot dynamically adjust the focal length, while liquid lenses can achieve dynamic changes in focal length by changing the shape of the droplets, which has significant practicality.

[0003] Existing technologies for regulating liquid lenses include the following methods:

[0004] Traditional liquid lenses usually change the shape of droplets through mechanical force or pressure, for example, by applying external mechanical force (such as compression or stretching) to adjust the surface tension of droplets. This method is not only complex in structure and bulky, which is not conducive to the integrated application of portable devices, but also has the problem of wear of mechanical parts, resulting in decreased accuracy after long-term use. In addition, since mechanical force adjustment involves actual physical displacement, it cannot achieve rapid adjustment and has a slow response speed, which cannot meet the scenarios that require fast real-time focusing.

[0005] Another common method of liquid lens control is to change the curvature of the lens by adjusting the flow of liquid through a microfluidic system. However, microfluidic systems are often complex in design, require precise fluid pipes and pump systems, and are highly sensitive to the external environment (such as temperature, air pressure, etc.), which increases the difficulty and cost of control. In addition, microfluidic control has a slow response speed due to the inertia of the fluid and the hysteresis of the system, making it difficult to achieve rapid dynamic adjustment, especially in scenarios where the focal length needs to be adjusted frequently in the optical system, and its flexibility and practicality are limited.

[0006] Although electrically controlled liquid lenses have gradually become a research hotspot in recent years, most existing electrically controlled systems rely on introducing conductive materials into droplets and changing the surface tension of the droplets by applying voltage. Although this method is feasible, the control accuracy of the droplet morphology is limited, especially when it is adjusted with high precision, it is easily interfered by environmental factors. In addition, this method has high requirements for surface materials, is susceptible to contamination, and has a complex manufacturing process, which restricts its feasibility of large-scale application.

[0007] Therefore, existing liquid lens technology faces the problems of difficulty in high-precision control, slow response speed, low degree of integration, and poor flexibility, making it difficult to achieve low-cost large-scale applications. Summary of the invention

[0008] In response to the above-mentioned problems in the existing liquid lens technology, the present invention proposes a device and method for electric field regulation of liquid lens and a sample observation method. A transverse electric field is generated by needle tip discharge, which directly acts on charged insulating droplets to achieve precise control of the shape and curvature of the droplets. The device has a fast response speed, is simple and easy to integrate, has high flexibility and low cost, and is convenient for large-scale application.

[0009] The present invention successfully solves the above problems by optimizing electrode design, electric field regulation method and system integration scheme. Specifically, the present invention achieves higher precision control, improves response speed and system integration, and prolongs the service life of the equipment through low power consumption design. In addition, by improving the electric field distribution and feedback control, the stability of the droplet morphology is ensured, thereby greatly improving the overall performance of the liquid lens, which is suitable for a variety of application scenarios such as portable devices and smart glasses.

[0010] The present invention realizes real-time dynamic adjustment of the liquid lens through a simple electric field control system, especially accurately controlling the shape, curvature and magnification of the droplets without relying on complex mechanical structures. Traditional liquid lenses often rely on external mechanical forces or complex microfluidic control during the adjustment process, while the present invention uses the electric field generated by needle tip discharge to confine the charged droplets in the micro-channel and act on them, dynamically adjusting the shape and curvature of the droplets, thereby achieving the effect of optical magnification. Compared with the electrowetting effect, the present invention generates a transverse electric field through needle tip discharge, which directly acts on the charged insulating droplets in the micro-channel, forming a system that does not require the addition of conductive materials to the droplets and is simple to control.

[0011] The present invention is specifically implemented through the following technical solutions.

[0012] A device for electric field regulation of liquid lens comprises a transparent conductive base electrode, the surface of the transparent conductive base electrode is covered with a transparent insulating film, an annular channel is opened on the transparent insulating film, a plurality of discharge needle tips are symmetrically distributed in the circumference of the channel and are placed laterally, insulating liquid droplets are dripped on the channel, and a conductive sample rod is arranged above the insulating liquid droplets.

[0013] Multiple discharge needle tips are used to provide a uniform transverse electric field to the insulating droplet, so that positive charges are distributed around the insulating droplet, and the local electric field formed in the channel is used to limit the insulating droplet; the charge distribution around the droplet is regulated by the transverse electric field, the transparent conductive substrate electrode and the sample rod, the electric field effect on the droplet is regulated, and then the morphology of the droplet is regulated.

[0014] Preferably, the width of the channel is 10 micrometers to 200 micrometers.

[0015] Preferably, the distance between each discharge needle tip and the center of the insulating droplet is 5 mm to 40 mm, the height distance between the discharge needle tip and the transparent insulating film is 1 mm to 5 mm; and the distance between the sample rod and the insulating droplet is 0.5 mm to 15 mm.

[0016] Preferably, the other end of each discharge needle tip is fixed on a base, the base is electrically connected to a power supply, the power supply is used to adjust the electric field strength of the transverse electric field, and the voltage applied to the transverse electric field by the power supply is 3kV to 10kV, and this range of voltage can achieve corona discharge but avoid electrical breakdown. The number of needle tips is 2 to 4, preferably 4, to provide a more stable electric field.

[0017] Preferably, the transparent conductive substrate electrode is made of ITO, which is suitable for precise control of liquid lenses due to its good light transmittance and conductivity, and its high transparency makes it easy to be photographed and observed by a camera. The transparent insulating film is made of PET, and the insulating droplets are PDMS droplets.

[0018] Preferably, the sample rod is connected to a motor via a connecting rod, and the motor is used to control the position of the sample rod relative to the insulating liquid droplet.

[0019] The present invention provides a method for regulating a liquid lens by an electric field, wherein the liquid lens is regulated by using the above device, and the method comprises the following steps:

[0020] A plurality of discharge needle tips are electrified to generate a uniform transverse electric field between the plurality of discharge needle tips, and the insulating liquid droplets are fixed in the channel under the action of the transverse electric field and the local electric field formed in the channel.

[0021] The transverse electric field provides positive charges to the insulating liquid droplet, and the contact angle, height and curved surface shape of the insulating liquid droplet are regulated by adjusting the electric field strength of the transverse electric field in cooperation with the transparent conductive substrate electrode and the sample rod.

[0022] Preferably, when the sample rod is negatively charged, the insulating liquid droplet is a convex lens, and when the sample electrode rod is positively charged, the insulating liquid droplet is a concave lens.

[0023] The present invention also provides a sample observation method, which uses the above device to observe the sample, comprising the following steps:

[0024] Fix the sample to be observed under the sample rod and adjust the sample to the top of the channel.

[0025] Insulating liquid droplets are dripped onto a transparent insulating film, and multiple discharge needle tips are energized to generate a transverse electric field at the discharge needle tips, thereby fixing the insulating liquid droplets in the channel.

[0026] A camera is placed below the transparent conductive substrate electrode and is aimed at the insulating droplet.

[0027] By adjusting the voltage applied to the discharge needle tip, the morphology of the insulating droplet is controlled, thereby changing the focusing effect of the insulating droplet, and the sample under the focus of the insulating droplet is observed using a camera.

[0028] Preferably, the diameter of the insulating liquid droplets to be added is selected according to the sample observation requirements, and as the diameter of the insulating liquid droplets increases, the focusing effect gradually weakens.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] The present invention provides a device and method for controlling a liquid lens by electric field, and a sample observation method, which generates a transverse electric field by needle tip discharge, directly acts on a charged insulating droplet, and achieves precise control of the droplet shape and curvature, with fast response speed, simple and easy integration of the device, high flexibility and low cost, and is convenient for large-scale application. Specifically, it is embodied in:

[0031] (1) Precisely control the droplet shape through electric field

[0032] The present invention covers a transparent insulating film on the surface of a transparent conductive base electrode. The transparent material makes it easy to observe the sample. An annular channel is opened on the transparent insulating film. A plurality of discharge needle tips are symmetrically distributed in the circumference of the channel. Insulating droplets are dripped at the channel, and a conductive sample rod is arranged above the insulating droplets. The plurality of discharge needle tips are used to provide a uniform transverse electric field to the insulating droplets, so that positive charges are distributed around the insulating droplets. The local electric field formed in the channel is used to limit the insulating droplets. The charge distribution around the droplets is regulated by the transverse electric field, the transparent conductive base electrode and the sample rod, thereby regulating the morphology of the droplets (contact angle, height, curved surface shape). Compared with mechanical regulation and microfluidic control methods, electric field regulation has higher flexibility and control accuracy, and has a fast response speed, and can realize real-time dynamic droplet morphology adjustment. In addition, compared with the electrowetting effect, the electric field regulation of the present invention generates a transverse electric field through needle tip discharge, which directly acts on the charged insulating droplets in the microchannel, without adding conductive substances to the droplets, and the regulation method is simple.

[0033] (2) Simple structure and low manufacturing cost

[0034] The core design of the present invention is an adjustable needle tip discharge system. Compared with traditional mechanical and microfluidic systems, the structure is simpler and lighter, and no complicated fluid pipelines and mechanical drive components are required. At the same time, the materials are all common materials, the manufacturing cost is relatively low, it is easy to mass produce, and it has high practicality.

[0035] (3) Highly flexible dynamic zoom

[0036] Through electric field regulation, the curvature of the droplet can be quickly changed, achieving seamless switching from convex lens to concave lens, thereby flexibly adjusting the focal length and magnification. In particular, by adjusting the electrode properties of the sample rod, the degree of concavity and convexity of the droplet can be further controlled, increasing the flexibility of droplet shape adjustment. This feature gives the present invention a significant advantage in scenarios that require real-time zoom, such as microscopic imaging and camera systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a schematic diagram of the structure of the device for electric field regulation of liquid lens provided by the present invention.

[0038] Figure 2 Schematic diagram of the cross-section of the device structure for electric field regulation of liquid lens.

[0039] Figure 3 Schematic diagram of insulating droplet control.

[0040] Figure 4 It is an electric field simulation diagram, where (a) is the electric field distribution diagram, (b) is the electric field intensity curve, and the embedded diagram in (b) is the direction of the electric field force.

[0041] Figure 5 This is a schematic diagram of the principle of the electric field regulating liquid lens of the present invention.

[0042] Figure 6 This is a diagram showing the experimental results of regulating the effect of electric field on droplet morphology in Example 1.

[0043] Figure 7 This is a graph showing the effect of different droplet diameters on the lens effect in Example 2.

[0044] Figure 8 In the figure, (a) shows the morphological changes of the PDMS droplet under different voltages, (b) is a graph showing the contact angle and height as a function of voltage, and (c) is the morphology of the PDMS droplet when there is no channel.

[0045] Fig. 9 The height of the PDMS droplet at different voltages and its focusing effect as a liquid lens, where (a) is the morphological change of the droplet and (b) is the focusing effect.

[0046] Fig.10 An actual image of an onion cell taken for the lens. DETAILED DESCRIPTION

[0047] In order to enable those skilled in the art to better understand the technical solution of the present invention and implement it, the present invention is further described below in conjunction with specific embodiments and drawings, but the embodiments are not intended to limit the present invention. The experimental methods and detection methods described in the following embodiments are conventional methods unless otherwise specified; the reagents and materials described are all commercially available unless otherwise specified.

[0048] Disadvantages of existing technology

[0049] 1. The adjustment method is complicated:

[0050] Traditional liquid lenses usually use mechanical force or microfluidic control to change the shape of droplets. The mechanical adjustment method requires external pressure to change the curvature of the droplet. This method not only requires a complex mechanical structure, but also has the problem of wear of mechanical parts, resulting in a decrease in accuracy after long-term use. At the same time, the mechanical system is large in size, which is not conducive to the integrated application of portable devices. Although microfluidic control can accurately control the shape of droplets, the system design is complex, requires precise fluid pipelines and pump systems, and is sensitive to environmental changes, which increases the difficulty and cost of control.

[0051] 2. Slow response:

[0052] Whether it is mechanical adjustment or microfluidic system, the existing liquid lens adjustment methods have the problem of slow response speed, which is difficult to meet the application scenarios that require fast zoom. Mechanical force adjustment cannot achieve fast adjustment because it involves actual physical displacement; and microfluidic regulation is also limited in response speed due to the inertia of the fluid and system lag.

[0053] 3. Limited control accuracy:

[0054] Electrowetting technology is another liquid lens control method that relies on introducing conductive materials into the droplets and changing the surface tension of the droplets by applying voltage. However, this method has limited control accuracy over the droplets, and is particularly susceptible to environmental contamination or the surface condition of the material during high-precision adjustments. In addition, the electrowetting system itself has high requirements for electrode materials, which are prone to aging and failure, affecting the long-term reliability of the system.

[0055] 4. High manufacturing cost:

[0056] Microfluidic control technology usually requires complex processing techniques and has high requirements for materials and environment, resulting in high manufacturing costs. Mechanical adjustment methods also increase production and maintenance costs due to their precise mechanical structure and complex adjustment mechanisms. Therefore, existing liquid lens technology has deficiencies in manufacturing costs and integration, making it difficult to achieve low-cost large-scale applications.

[0057] In order to solve the problems of complex adjustment, slow response speed, limited control accuracy and high manufacturing cost in the prior art, the purpose of the present invention is to design a device and method for electric field control of liquid lens and a sample observation method, which generates a transverse electric field through needle tip discharge to act on the charged droplets in the channel, so as to realize real-time dynamic control of the droplet shape, thereby achieving flexible adjustment of the optical focal length and curvature. Specifically, the main objectives of the present invention are:

[0058] 1. Simplified adjustment method:

[0059] By using a four-pinpoint discharge device, the electric field is used to act on the charged droplets in the microchannel, replacing the traditional mechanical adjustment or microfluidic control method. Electric field regulation is not only simple in structure and does not require complex mechanical structures or microfluidic systems, but can also directly change the shape of the droplets by adjusting the voltage, thus achieving precise control of the liquid lens.

[0060] 2. Improve response speed:

[0061] Since the local electric field on the microchannel acts very quickly, the present invention can achieve rapid changes in the shape of the droplet, thereby greatly improving the response speed of the liquid lens. Compared with the hysteresis of mechanical displacement or microfluidic systems, the present invention can meet the needs of real-time dynamic focusing and is suitable for optical systems with high-frequency changes.

[0062] 3. Improve control accuracy:

[0063] The present invention directly regulates the charge distribution around the microchannel through the electric field, and can accurately control the contact angle, curvature and surface shape of the droplet, thereby achieving highly flexible focal length adjustment. Compared with electrowetting technology, needle tip discharge does not require the addition of conductive materials to the droplet, avoiding the instability caused by contamination or material aging, and improving the long-term service life and stability of the system.

[0064] 4. Reduce manufacturing costs:

[0065] The materials and devices used in the present invention (such as ITO glass, PET film, PDMS droplets, etc.) are all common, low-cost optoelectronic materials. The entire system has a simple structure and is easy to manufacture, which can reduce the overall manufacturing cost. In addition, the needle tip discharge control device does not require complex processing technology or precision mechanical structure, and is suitable for large-scale production applications.

[0066] By achieving the above objectives, the present invention overcomes the defects of the prior art, achieves breakthroughs in the liquid lens in terms of simple structure, precise control, fast response and low cost, and has broad application prospects.

[0067] Specifically, the present invention provides a device for regulating a liquid lens by an electric field, such as Figure 1 , Figure 2 and Figure 3As shown, it includes a transparent conductive base electrode 3, and the surface of the transparent conductive base electrode 3 is covered with a transparent insulating film 1. In order to facilitate the camera to observe the sample, the transparent conductive base electrode 3 is made of ITO, which has good light transmittance and conductivity and is suitable for precise control of the liquid lens. The material of the transparent insulating film 1 is PET, and an annular channel 10 is opened on the transparent insulating film 1. The channel 10 is symmetrically distributed with multiple horizontally placed discharge needle tips 2. Insulating liquid droplets 9 are dripped at the channel 10, and the insulating liquid droplets 9 are PDMS liquid droplets. A conductive sample rod 8 is arranged above the insulating liquid droplets 9.

[0068] Multiple discharge needle tips 2 are used to provide a uniform transverse electric field to the insulating droplet 9, so that positive charges are distributed around the insulating droplet 9, and the local electric field formed in the channel 10 is used to limit the insulating droplet 9; the electric field effect on the insulating droplet 9 is regulated by the transverse electric field, the transparent conductive base electrode 3 and the sample rod 8, thereby regulating the shape of the insulating droplet 9.

[0069] The functions of the above components are as follows: the transparent insulating film 1 is used to cover the surface of the ITO glass, a channel 10 is etched in the center, and the conductive area is used to control the shape of the insulating droplet 9.

[0070] Discharge needle tips 2: Multiple discharge needle tips 2 are placed horizontally, and a horizontal electric field is generated by adjusting the distance between the needle tips and the voltage, thereby acting on the charge distribution around the insulating droplet 9.

[0071] The transparent conductive substrate electrode 3 forms an electric field to cooperate with the discharge needle tip 2 to control the shape of the insulating liquid droplet 9.

[0072] The sample rod 8 is used to place the sample to be observed, and the electrode properties of the sample rod 8 can also adjust the curvature of the insulating droplet 9.

[0073] Preferably, the width of the channel 10 is 10 microns to 200 microns. The distance between each discharge needle tip 2 and the center of the insulating droplet 9 is 5mm to 40mm, and the height distance between the discharge needle tip 2 and the transparent insulating film 1 is 1mm to 5mm; the distance between the sample rod 8 and the insulating droplet 9 is 0.5mm to 15mm. The other end of each of the discharge needle tips 2 is fixed on the base 5, and the base 5 is electrically connected to the power supply 4. The power supply 4 is used to adjust the electric field strength of the transverse electric field. The voltage applied to the transverse electric field by the power supply 4 is 3kV to 10kV. This range of voltage can achieve corona discharge, but can avoid electrical breakdown. The number of discharge needle tips 2 is 2 to 4, preferably 4, and the electric field provided is more stable.

[0074] Preferably, the sample rod 8 is connected to the motor 7 via a connecting rod, and the motor 7 is used to control the position of the sample rod 8 relative to the PDMS droplet. The motor 7 is a three-axis stepping motor.

[0075] The present invention provides a method for regulating a liquid lens by an electric field, wherein the liquid lens is regulated by using the above device, and the method comprises the following steps:

[0076] The plurality of discharge needle tips 2 are energized to generate a uniform transverse electric field between the plurality of discharge needle tips 2 , and the insulating liquid droplet 9 is fixed in the channel 10 under the action of the transverse electric field and the local electric field formed in the channel 10 .

[0077] The transverse electric field provides positive charges to the insulating liquid droplet 9 . By adjusting the electric field strength of the transverse electric field, the contact angle, height and curved surface shape of the insulating liquid droplet 9 are regulated in cooperation with the transparent conductive substrate electrode 3 .

[0078] By adjusting the electrode properties of the sample rod 8, the curvature of the insulating liquid droplet 9 is controlled. When the sample rod 8 is negatively charged, the insulating liquid droplet 9 is a convex lens, and when the sample rod 8 is positively charged, the insulating liquid droplet 9 is a concave lens.

[0079] The present invention provides a sample observation method, which uses the above device to observe the sample, comprising the following steps:

[0080] The sample to be observed is fixed below the sample rod 8 , and the sample is adjusted to above the channel 10 .

[0081] An insulating liquid droplet 9 is dripped onto the transparent insulating film 1 , and a plurality of discharge needle tips 2 are energized to generate a transverse electric field at the discharge needle tips 2 , thereby fixing the insulating liquid droplet 9 at the channel 10 .

[0082] A camera 6 is placed below the transparent conductive base electrode 3 , and is directed toward the insulating liquid drop 9 .

[0083] The voltage applied to the discharge needle tip 2 is adjusted to control the shape of the insulating droplet 9, thereby changing the focusing effect of the insulating droplet 9, and the camera 6 is used to observe the sample under the focus of the insulating droplet 9.

[0084] The diameter of the insulating liquid droplet 9 to be added is selected according to the sample observation requirements. As the diameter of the insulating liquid droplet 9 increases, the focusing effect gradually weakens.

[0085] The present invention controls the morphology of charged droplets through electric fields, breaking through the limitations of existing liquid lens adjustment systems in mechanical structure and microfluidic systems. It has the advantages of simple structure, fast response and high adjustment accuracy, and is suitable for a variety of optical imaging systems.

[0086] Depend on Figure 4 As can be seen from the electric field simulation diagram, the simulation results show the force and electric field distribution of the charged PDMS droplet in the electric field.

[0087] (a) The figure is an electric field distribution diagram, showing the distribution of the lateral electric field, using color to represent the magnitude of the electric potential, from red (high potential) to blue (low potential). It can be observed that the electric field forms a ring structure in the central area of ​​the figure, representing the change in electric field strength. The white arrow indicates the direction of the electric field, which points from the high potential area (red) to the low potential area (blue). This ring-shaped electric field distribution is consistent with the force conditions of the charged PDMS droplet under the electric field, indicating that the electric field will compress or stretch the shape of the droplet, thereby adjusting the shape of the droplet.

[0088] (b) is the electric field intensity curve, showing the electric field intensity distribution curve on the cross section of \(y=0\). It can be seen from the figure that the electric field intensity reaches a local extreme value at \(x=-3.71\) mm, which corresponds to the area where the droplet is located. The positive and negative peaks of the curve indicate that the electric field generates a large force in certain areas, which can further act on the charged droplet, causing the droplet to deform in a specific area.

[0089] (b) The inset in the figure shows the direction of the electric field force, which illustrates the direction of the electric field force on the droplet. The yellow arrow indicates the direction of the electric field, showing how the shape of the droplet can be controlled by the electric field. Near the center of the droplet, the electric field pushes outward, while in the outer ring area, the electric field pulls inward. This electric field distribution helps to adjust the curvature and surface morphology of the droplet, thereby achieving control of the liquid lens.

[0090] Summarize

[0091] Figure 4 The simulation diagram verifies that the morphology of the droplet can be precisely controlled through the action of the lateral electric field. The distribution of the electric field strength is consistent with the force applied to the droplet. By adjusting the voltage and the electric field distribution, the droplet's morphology can be precisely controlled, thereby changing the droplet's curvature and adjusting the focal length and magnification of the liquid lens.

[0092] Figure 5 This is a schematic diagram of the electric field controlled liquid lens of the present invention, showing the working principle of the liquid lens based on electric field control, which mainly adjusts its shape by acting on the droplet with the electric field. The following is a breakdown of the diagram:

[0093] The central cylindrical object: The top object is the sample rod, which can change the direction and strength of the electric field, thereby affecting the shape of the droplet. The purple symbol at the bottom represents the negatively charged electrode.

[0094] Charged droplet: The droplet in the center of the image (blue part) is an insulating droplet (specifically a PDMS droplet). Positively charged particles (green circle with a cross symbol) are distributed around it, indicating that the droplet is charged under the action of the electric field. The shape of the charged droplet is affected by the electric field. Through the discharge of the needle tip, the positive and negative charges interact with each other, generating forces that change the contact angle and surface shape of the droplet.

[0095] Needle tips on both sides: The gray tips on both sides of the picture represent the discharge needle tips, and the voltage difference between the needle tips (red arrows) forms a transverse electric field. This electric field force causes the droplets to gather toward the center and change their shape.

[0096] ITO glass and PET film: The gray area below the droplet is ITO glass, and its surface is covered with a light blue PET film. The center of the film may contain a conductive micro-channel, which serves as a carrying surface for the charged droplet.

[0097] Electric field direction: The red arrow in the figure indicates the direction of charge movement, and the black arrow indicates the direction of the electric field. The shape of the droplet is regulated by the electric field.

[0098] In general, this schematic diagram shows that by controlling the discharge voltage at the tip of the needle, the electric field is used to act on the charged insulating droplet (specifically PDMS droplet), and the shape of the droplet changes, forming the effect of a liquid lens. This principle is used to adjust the curvature of the droplet in real time, thereby achieving optical magnification.

[0099] The present invention directly controls the shape of the PDMS droplet through the needle tip discharge system and the electric field effect, thereby achieving real-time morphological adjustment of the droplet. Specifically:

[0100] 1. Discharge and electric field control: By adjusting the four-needle tip discharge device, a lateral electric field is formed to act on the PDMS droplet, changing its curvature. The electric field strength is controlled by an adjustable high-voltage power supply, which can achieve dynamic adjustment of the droplet.

[0101] 2. Droplet morphology adjustment: The morphology of the droplet is regulated by the electric field. By changing the voltage, the contact angle, height and surface shape of the droplet can be adjusted to achieve seamless switching from convex lens to concave lens.

[0102] 3. Imaging and magnification: The liquid lens is located above the camera, and the sample can be observed in real time through the droplets. Through electric field control, the focal length can be adjusted to dynamically magnify or reduce the observed image.

[0103] 4. Sample position adjustment: The three-axis stepper motor can accurately adjust the position of the sample rod to ensure that the optical path of the sample and the droplet are aligned to achieve the best imaging effect.

[0104] The present invention is described in detail below in conjunction with the following content: In the following content, the transparent insulating film 1 is specifically selected from a PET film, the transparent conductive substrate electrode 3 is specifically ITO glass, and the insulating droplet is specifically a PDMS droplet.

[0105] Example 1

[0106] Experiment on the regulation of droplet morphology by electric field

[0107] This example demonstrates that the PDMS droplet shape can be changed from a convex lens to a concave lens by adjusting the electric field voltage and polarity. In the experiment, positive and negative charges were applied to both ends of the electrode, and the change in the droplet shape was observed by changing the voltage.

[0108] 1. Experimental composition:

[0109] The PDMS droplet was placed on the ITO glass on the surface of the PET film and surrounded by four needle-tip discharge devices.

[0110] Different voltages are applied to the positive and negative electrodes through an adjustable high-voltage power supply, thereby forming a transverse electric field.

[0111] The three-axis stepper motor is used to precisely adjust the position of the sample holder.

[0112] 2. Experimental steps:

[0113] The voltage was increased stepwise (from 3.8 kV to 4.6 kV), and the height and morphology changes of the droplets were recorded.

[0114] The camera is used to record the side view of the droplet at different voltages, and the focusing or scattering of light by the droplet is observed through the lens effect.

[0115] 3. Experimental results, such as Figure 6 As shown:

[0116] As the voltage increases, the droplet gradually changes from a convex spherical shape to a flat shape, and finally forms a concave lens at a higher voltage.

[0117] like Figure 6 As shown, under different voltages, the droplet height and focal length also change accordingly, indicating that the electric field can precisely control the morphology of the droplet.

[0118] The results show that by changing the electric field voltage, the droplet can be seamlessly switched from a convex lens to a concave lens.

[0119] 4. Effect:

[0120] Experiments have shown that electric field control technology can accurately adjust the shape of droplets, thereby controlling the curvature of the liquid lens and achieving dynamic zoom function.

[0121] The electric field responds quickly and can achieve changes in droplet morphology in a short time, making it suitable for dynamic imaging systems.

[0122] Example 2

[0123] Effect of different droplet diameters on lens effect

[0124] This embodiment studies the effect of the change in droplet diameter on the focusing effect of the lens and explores the imaging characteristics of droplets of different sizes under the same voltage. The actual size of the grid is 100 microns, and the grid line thickness is 10 microns.

[0125] 1. Experimental composition:

[0126] Three droplets with different diameters (0.7 mm, 1.6 mm, and 2.3 mm) were placed on the same ITO glass and PET film, respectively.

[0127] The voltage was fixed at 4 kV to keep the electric field strength constant.

[0128] Record the side view of the droplet and its imaging effect on the optical object.

[0129] 2. Experimental steps:

[0130] Droplets of three different diameters were placed in an electric field, maintaining the same voltage and electric field conditions.

[0131] Observe and record the shape of the droplets and their focusing effect on light, and measure the magnification of the droplets on light.

[0132] 3. Experimental results, such as Figure 7 As shown:

[0133] Droplets with a smaller diameter (0.7 mm) can focus light, creating a clearer magnification effect.

[0134] As the droplet diameter increases, the focusing effect gradually weakens, and larger droplets (2.3 mm) produce a more scattered imaging effect, making it difficult to form a clear focus.

[0135] The results show that the diameter of the droplet has a significant effect on the optical properties of the liquid lens, with smaller droplets being suitable for precision imaging and larger droplets being more suitable for wide-angle imaging.

[0136] 4. Effect:

[0137] Experiments have shown that the size of the droplet can significantly affect the focusing performance of the lens. The present invention can achieve different requirements for the optical system by adjusting the droplet size, thereby achieving flexible optical adjustment in a wide range of application scenarios.

[0138] Different voltages (3.6 kV to 5.2 kV) were applied to the PDMS droplets to observe the morphological changes of the PDMS droplets, and the changing trends of the contact angle and height were displayed through a curve graph. Figure 8 shown.

[0139] The following are Figure 8 Detailed analysis of the experimental results:

[0140] Figure 8 Middle (a): Experimental results of droplet morphology changing with voltage

[0141] The experiment showed that as the voltage gradually increased from 3.6kV, the morphology of the droplets underwent significant changes. At first, the droplet morphology was a convex lens close to a circle. When the voltage increased to 4.8kV, the droplet height reached the maximum, and the morphology was the fullest at this time. As the voltage was further increased, the droplet gradually became flatter, and even at 5.2kV, the droplet height almost completely disappeared, the contact angle also decreased significantly, and the morphology tended to be flat.

[0142] (b) Graph showing contact angle and height versus voltage

[0143] Contact angle (blue curve): The contact angle increases first and then decreases with the increase of voltage. When the voltage reaches 4.8 kV, the contact angle reaches a peak value (about 150°), at which time the droplet morphology is the fullest. As the voltage increases further, the contact angle decreases rapidly.

[0144] Height (orange curve): The droplet height also increases with the increase of voltage, reaching a maximum value (about 1.2 mm) at 4.8 kV. When the voltage continues to increase to above 5.0 kV, the droplet height decreases rapidly.

[0145] (c) When there is no channel, the stability of the droplet is reduced and a stable state cannot be formed. The contact angle of the droplet is also much smaller than that when there is a channel.

[0146] in conclusion:

[0147] The electric field has a significant effect on the droplet morphology: From the experimental results, the electric field strength directly affects the contact angle and height of the droplet, especially at 4.8kV, the droplet morphology is most prominent. This shows that within a certain voltage range, the electric field can effectively control the droplet morphology and form the best liquid lens shape.

[0148] Too high a voltage causes the droplets to flatten: When the voltage exceeds 4.8 kV, the droplets gradually lose height and eventually become flat at 5.2 kV. This may be because the electric field is too strong, resulting in uneven force distribution on the droplets, which in turn changes their surface tension and makes it difficult for the droplets to maintain a lens shape.

[0149] Technology Application:

[0150] The experimental results show that by controlling the voltage, the morphology of the liquid lens can be flexibly adjusted to achieve the conversion from a convex lens to a concave lens. The optimal voltage range should be maintained between 4.4kV and 4.8kV, when the morphology of the liquid lens is the fullest, suitable for high-precision imaging and dynamic zoom systems.

[0151] Fig. 9 The height of the PDMS droplet and its focusing effect as a liquid lens are demonstrated at different voltages (3.8 kV to 4.6 kV).

[0152] (a) Changes in droplet morphology

[0153] It can be seen that as the voltage increases from 3.8kV to 4.6kV, the morphology of the droplets changes significantly. At a lower voltage (3.8kV), the droplet height is smaller, and as the voltage increases, the droplets gradually become fuller, especially between 4.2kV and 4.4kV, the droplet height and morphology tend to be optimal, close to the ideal convex lens morphology.

[0154] (b) Focusing effect diagram

[0155] The effect of the droplet as a liquid lens changes as the voltage increases. It can be seen that at 4.2kV and 4.4kV, the optical image seen through the droplet is the clearest and the light spot is the most concentrated, indicating that the droplet shape at this time is most suitable for use as a lens and can better focus light.

[0156] At a lower voltage (3.8 kV), the focusing effect is more blurred and the light spot is more scattered, indicating that the droplet morphology is not suitable for focusing.

[0157] At 4.6 kV, the droplets still focus the light, but the focusing effect begins to decline and the spot becomes slightly diffuse.

[0158] in conclusion:

[0159] Optimal voltage range: From the experimental results, the voltage between 4.2kV and 4.4kV can form the best liquid lens shape and the best focusing effect. At this time, the droplet can form a relatively ideal convex lens shape, which is suitable for imaging and optical magnification.

[0160] Excessive voltage affects the focusing effect: When the voltage increases to 4.6 kV, although the droplets still maintain a certain focusing ability, the effect has begun to weaken, indicating that excessive voltage will cause the droplet morphology to be out of control and affect the lens performance.

[0161] Application scenarios:

[0162] These experimental results indicate that the liquid lens technology of the present invention can realize dynamic zoom function by adjusting voltage, and has significant application potential in scenarios requiring precise focusing, such as optical imaging and microscopy systems.

[0163] Fig.10 Actual onion cells photographed by the lens. The focus is on the local electric field generated by the microchannel, which can well confine the droplets, and then achieve a large range of droplet morphology adjustment.

[0164] As can be seen from the above, the present invention achieves the following objectives:

[0165] 1. The adjustment method is simplified and the accuracy is high

[0166] Directly controlling the morphology of charged droplets through electric fields replaces the common mechanical force or microfluidic system regulation methods in traditional liquid lens technology. The electric field regulation method is not only simple in structure and small in size, but also can accurately control the contact angle and surface shape of the droplets, achieving rapid and seamless switching of the droplets from concave lenses to convex lenses. Compared with mechanical or microfluidic control, electric field regulation has higher regulation accuracy and flexibility.

[0167] 2. Fast response speed, suitable for dynamic optical systems

[0168] Due to the extremely fast speed of the electric field, the present invention can achieve real-time dynamic adjustment of the droplet morphology, greatly improve the response speed, and is suitable for dynamic optical systems that require frequent zooming and rapid focal length adjustment. This provides significant performance improvements for application scenarios such as camera equipment, microscopic imaging, and intelligent optical devices.

[0169] 3. Simple structure and low manufacturing cost

[0170] The present invention adopts a simple design framework, including common materials such as needle tip discharge device, ITO glass, PET film and PDMS droplets, avoiding complex mechanical structure or microfluidic control system, reducing manufacturing and maintenance costs. At the same time, these materials are easy to process, convenient for large-scale production and application, and have good market prospects.

[0171] 4. Multifunctional optical adjustment

[0172] The present invention can not only adjust the focal length of the liquid lens through electric field control, but also adjust the curvature of the droplet by further regulating the electrode properties of the sample rod, thereby enhancing the zoom and imaging capabilities of the optical system. The liquid lens can act as both a convex lens and a concave lens in the optical system, greatly improving the versatility of the optical device.

[0173] 5. Strong operational stability

[0174] The microchannel design of ITO glass and PET film ensures that the droplets can be stably aggregated and formed into a lens shape under the control of the electric field, avoiding the fluctuation or loss of control of the droplet shape. This stability makes the device highly reliable in long-term use and reduces the impact of adjustment errors and environmental factors on performance.

[0175] 6. Strong adaptability and wide application

[0176] The liquid lens device of the present invention is suitable for a variety of scenarios, including microscope imaging, smartphone cameras, zoom lenses, and other optical systems that require dynamic focal length adjustment. It is particularly suitable for scenarios that require real-time zoom and high-precision imaging, such as medical imaging, cameras in autonomous driving systems, astronomical observation equipment, etc.

[0177] 7. Low power consumption and high performance

[0178] Since the electric field regulation consumes less energy, the liquid lens of the present invention has lower power consumption and is suitable for portable devices or optical applications with high energy efficiency requirements. Compared with the mechanical regulation system, the electric field regulation scheme is not only highly efficient, but also has low operating noise, which is very suitable for the integrated use of modern smart devices and optical systems.

[0179] 8. The controllability of droplet morphology is further enhanced

[0180] By adjusting the electrode properties of the sample rod, the present invention can not only adjust the curvature and height of the droplet, but also change the overall shape of the droplet, further improving the controllability of the liquid lens. This flexible control feature makes the application of the lens more diverse, especially in optical imaging and zoom, achieving a major technological breakthrough.

[0181] 9. Environmental protection and sustainability

[0182] The materials used, such as PDMS and ITO glass, are environmentally friendly and do not produce harmful chemicals during the manufacturing process. In addition, the high efficiency and low power consumption design of the device make it have little impact on the environment during use, which meets the current technological trend requirements for environmental protection and sustainable development.

[0183] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, they are also intended to be included.

Claims

1. A device for controlling a liquid lens by an electric field, characterized in that: The invention comprises a transparent conductive base electrode (3), the surface of the transparent conductive base electrode (3) is covered with a transparent insulating film (1), an annular channel (10) is provided on the transparent insulating film (1), a plurality of discharge needle tips (2) are symmetrically distributed in the circumferential direction of the channel (10), an insulating liquid drop (9) is dripped on the channel (10), and a conductive sample rod (8) is arranged above the insulating liquid drop (9); The plurality of discharge needle tips (2) are used to provide a uniform transverse electric field to the insulating liquid droplet (9), so that positive charges are distributed around the insulating liquid droplet (9); the local electric field formed in the channel (10) is used to limit the insulating liquid droplet (9); the charge distribution around the insulating liquid droplet (9) is regulated by the transverse electric field, the transparent conductive base electrode (3) and the sample rod (8), thereby regulating the morphology of the insulating liquid droplet (9).

2. The device for controlling a liquid lens by electric field according to claim 1, characterized in that: The width of the channel (10) is 10 μm to 200 μm.

3. The device for controlling a liquid lens by electric field according to claim 1, characterized in that: The distance between each discharge needle tip (2) and the center of the insulating liquid droplet (9) is 5 mm to 40 mm, the height between each discharge needle tip (2) and the transparent insulating film (1) is 1 mm to 5 mm; and the distance between the sample rod (8) and the insulating liquid droplet (9) is 0.5 mm to 15 mm.

4. The device for controlling a liquid lens by electric field according to claim 1, characterized in that: The other end of each discharge needle tip (2) is fixed on a base (5), and the base (5) is electrically connected to a power supply (4). The power supply (4) is used to adjust the electric field strength of the transverse electric field. The voltage applied by the power supply (4) to the transverse electric field is 3 kV to 10 kV.

5. The device for controlling a liquid lens by electric field according to claim 1, characterized in that: The transparent conductive base electrode (3) is made of ITO, the transparent insulating film (1) is made of PET, and the insulating liquid droplet (9) is a PDMS liquid droplet.

6. The device for controlling a liquid lens by electric field according to claim 1, characterized in that: The sample rod (8) is connected to the motor (7) via a connecting rod, and the motor (7) is used to control the position of the sample rod (8) relative to the insulating liquid droplet (9).

7. A method for controlling a liquid lens by electric field, characterized in that: Using the device of claim 1 to control the liquid lens comprises the following steps: The plurality of discharge needle tips (2) are energized to generate a uniform transverse electric field between the plurality of discharge needle tips (2), and the insulating liquid droplet (9) is fixed in the channel (10) under the action of the transverse electric field and the local electric field formed in the channel (10); The transverse electric field provides positive charges to the insulating liquid droplet (9), and by adjusting the electric field intensity of the transverse electric field, the contact angle, height and curved surface shape of the insulating liquid droplet (9) are regulated in cooperation with the transparent conductive base electrode (3) and the sample rod (8).

8. The method according to claim 7, characterized in that When the sample rod (8) is negatively charged, the insulating liquid drop (9) is a convex lens, and when the sample electrode rod (8) is positively charged, the insulating liquid drop (9) is a concave lens.

9. A sample observation method, characterized in that: Observing a sample using the device of claim 1 comprises the following steps: Fix the sample to be observed below the sample rod (8), and adjust the sample to the top of the channel (10); Insulating liquid droplets (9) are dripped onto a transparent insulating film (1), and multiple discharge needle tips (2) are electrified so that the discharge needle tips (2) generate a transverse electric field, thereby fixing the insulating liquid droplets (9) at the channel (10); A camera (6) is placed below the transparent conductive substrate electrode (3), and the camera (6) is directed toward the insulating liquid droplet (9); The voltage applied to the discharge needle tip (2) is adjusted to control the shape of the insulating liquid droplet (9), thereby changing the focusing effect of the insulating liquid droplet (9), and the camera (6) is used to observe the sample under the focus of the insulating liquid droplet (9).

10. The method according to claim 9, characterized in that The diameter of the insulating liquid droplet (9) to be added is selected according to the sample observation requirements, and as the diameter of the insulating liquid droplet (9) increases, the focusing effect gradually weakens.

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