Metal-liquid composite micro lens and preparation method and super-resolution detection method thereof

Abstract

The invention discloses a metal-liquid composite micro-lens and a preparation method and a super-resolution detection method thereof, and belongs to the technical field of optical microscopic detection, and the metal-liquid composite micro-lens for super-resolution imaging is prepared by utilizing a metal nanoparticle liquid-liquid interface self-assembly and particle blocking technology to enable a two-layer liquid structure to tend to be in an equilibrium state. And nano / angstrom super-resolution imaging detection is realized. By adjusting the magnitude of voltage, regulating and controlling the magnitude of electric field force, controlling the arrangement of nano particles and utilizing an external field with a functionalized space structure to act on the upper side and the lower side of the nano particles, the morphology of the micro lens is regulated and controlled, and the highest matching performance of the spatial form of the metal-liquid composite micro lens during super-resolution detection is achieved; through evanescent wave coupling and system frequency spectrum continuation, the morphology characteristics of the micro lens and the arrangement characteristics of the nano particles are known respectively, and under the synergistic effect of the micro lens and the nano particles, optimal imaging detection of the metal-liquid composite micro lens is achieved.

Description

Technical Field

[0001] The present invention belongs to the field of optical microscopic detection technology, relates to the field of micro-nano manufacturing, the manufacture of nano metal particles and composite micro lenses, and also relates to the analysis of detection methods using physical optics and geometric optics, and specifically relates to a metal-liquid composite micro lens and a preparation method thereof and a super-resolution detection method. Background Art

[0002] In the field of new optical technology, technical challenges such as ultra-precision aberration control, ultra-high resolution detection, extremely weak signal acquisition, and large-capacity information transmission have also put forward new requirements for imaging methods that break through the optical diffraction limit.

[0003] Although complex and expensive non-optical detection technologies (such as scanning electron microscopes, scanning tunneling microscopes, atomic force microscopes, etc.) can achieve angstrom detection, they will inevitably lose the detection object and have strict requirements on the detection speed and detection environment. Optical detection technology, which is simple to operate and low in cost, can achieve in-situ, real-time, low environmental restrictions, and non-destructive detection, and has become a precision measurement method with great development potential. Therefore, with the development of advanced nano-processing and manufacturing technologies and the demand for new nano-characterization and observation technologies, advancing optical microscopy detection technology to the nanometer or even angstrom scale has become one of the hot issues in ultra-precision measurement research. In addition, the development of real-time, localized, and actively controllable microlenses with plasmon light field structures, regulating the coupling of evanescent waves, the expansion of frequency domain space, and the shift of passbands can fundamentally further improve the imaging quality and resolution, and realize adaptive detection of nano / angstrom structures of complex and special-shaped samples.

[0004] The key to the coupled manufacturing of microlenses and three-dimensional plasmons with strong mechanical stability lies in the self-assembly of nanoparticles constrained by interface forces. The following studies have been conducted in this regard: 1) Confined space evaporation induction technology: By regulating the dynamic process of droplet evaporation and changing the three-phase line contact, large-scale orderly assembly of nanoparticles can be achieved. However, the nanoparticle assembly obtained by this method is mostly two-dimensional film-like and randomly distributed on the substrate, making it difficult to achieve precise assembly of nanoparticles on flexible three-dimensional surfaces; 2) Patterned template induction technology: With the help of physical templates, the movement behavior and assembly morphology of nanoparticles are regulated to achieve high-precision orientation and arrangement of nanoparticles. However, due to the difficulty in controlling the assembly driving force and the polydispersity of the assembly units, it is difficult for nanoparticles to overcome the kinetic adsorption barrier and reach the interface self-aggregation state. Therefore, the assembly structure usually has unavoidable problems such as long-range disorder and assembly defects; 3) Micro-nano processing technology: Print nanoparticles with a high concentration on the hydrophobic structure, and promote the accumulation and assembly of nanoparticles through the retraction of the three-phase contact line. This method relies on complex printing equipment, is greatly affected by the wettability and adhesion of the substrate surface, and is difficult to regulate the drag and slip of the three-phase line, resulting in poor mechanical stability of the assembled structure. Summary of the invention

[0005] The present invention aims at the difficulties in manufacturing and coordinated control of the coupling of microlens-nanoparticle structures, takes multi-parameter active modulation of super-resolution imaging detection as the application goal, and proposes a metal-liquid composite microlens with controllable spatial morphology. The coupling structure is characterized by metal nanoparticles uniformly assembled on the surface of the liquid microlens. Under the action of external field modulation, the morphology of the liquid microlens and the arrangement of nanoparticles on the interface produce localized deformation. Under the synergistic effect of evanescent wave coupling and plasmon enhancement, through the observation of the metal-liquid composite microlens and an optical microscope, real-time, localized adaptive detection of complex and shaped samples can be achieved.

[0006] In order to achieve the above object, the present invention adopts the following technical solution: A metal-liquid composite microlens comprises a substrate and an ultraviolet curing adhesive coating arranged on the substrate, wherein the ultraviolet curing adhesive coating is provided with one or more micropores arranged in an array form, the micropores are filled with a glycerol solution, and a two-layer hemispherical liquid microlens is provided on the top of the micropore, wherein the inner liquid microlens is made of a glycerol solution, and the outer liquid microlens is an ultraviolet curing adhesive film, and the ultraviolet curing adhesive film is covered with metal nanoparticles.

[0007] Furthermore, the UV-curable adhesive coating is UV-curable adhesive NOA71.

[0008] Furthermore, the substrate is indium tin oxide ITO glass. The above-mentioned method for preparing a metal-liquid composite microlens comprises the following steps: Step 1, making a micro-column template; Step 2, preparing a UV-curable adhesive coating on the surface of the substrate, then imprinting the micro-column template prepared in step 1 onto the UV-curable adhesive coating, curing the UV-curable adhesive coating, and peeling off the micro-column template to obtain a microporous structure, wherein the microporous structure is a UV-curable adhesive coating having a plurality of micropores; Step 3, performing plasma treatment on the microporous structure obtained in step 2 to make the microporous structure hydrophobic; Step 4, placing the hydrophobic microporous structure prepared in step 3 into a container containing a glycerol solution, and converting the Cassie-Baxter state where the glycerol solution contacts the microporous structure into a Wenzel state by liquid immersion and vacuum degassing; Step 5, the hydrophobic microporous structure is pulled at a uniform speed, and at the gas-liquid-solid three-phase interface formed by air, glycerol solution and microporous structure, under the combined action of interfacial force and shear stress, the glycerol solution is spontaneously assembled in the hydrophobic microporous structure to form a hemispherical film, thereby obtaining a single-layer liquid microlens array; Step 6, immersing the single-layer liquid microlens array obtained in step 5 in a UV-curable adhesive solution in which metal nanoparticles are uniformly dispersed, and then pulling the substrate with the single-layer liquid microlens array, so that the metal nanoparticles are spread on the surface of the glycerol solution through interfacial forces and intermolecular interactions along with the UV-curable adhesive solution to form a UV-curable adhesive film containing metal nanoparticles, thereby obtaining a metal-liquid composite microlens array; Step 7, adding an electrode plate above the metal-liquid composite microlens array obtained in step 6, adding a gasket between the substrate and the electrode plate, and applying an electric field to make the metal nanoparticles and the liquid in a state of equilibrium, so that the metal nanoparticles are gathered and arranged along the outer surface of the liquid microlens; then remove the applied voltage, adjust the interface force between the metal nanoparticles, so that the nanoparticles can be stably maintained on the liquid surface without falling back into the liquid.

[0009] Furthermore, the specific process of step 2 is: evenly spin-coating a layer of UV-curable adhesive solution on the surface of the substrate to form a UV-curable adhesive coating, covering the UV-curable adhesive coating with a microcolumn template and applying uniform pressure, then curing the UV-curable adhesive coating by UV irradiation, peeling off the microcolumn template, and obtaining a microporous structure.

[0010] Furthermore, the specific process of step 3 is: introducing C4F8 as a fluorine source into the plasma reaction chamber, exciting C4F8 by plasma, decomposing it and forming a fluorinated carbon layer on the surface of the microporous structure, so that the microporous structure has a hydrophobic property.

[0011] Furthermore, the specific process of step 4 is: placing the hydrophobic microporous structure into a container containing propylene glycol solution and immersing it, then placing the container containing the propylene glycol solution and the microporous structure into a vacuum chamber, removing the bubbles in the microporous structure by vacuuming, and finally taking the container out of the vacuum chamber. The propylene glycol solution completely fills the interior of the microporous structure, and the wetting state of the microporous structure changes from the Cassie-Baxter state to the Wenzel state.

[0012] Furthermore, the specific process of step 7 is as follows: adding an electrode plate above the metal-liquid composite microlens array obtained in step 6, adjusting the distance between the electrode plate and the substrate of the metal-liquid composite microlens, adding a gasket between the electrode plate and the substrate and applying an electric field to drive the metal nanoparticles to move toward the interface toward the electrode plate, and gather and arrange along the outer surface of the microlens; after the metal nanoparticles move to the liquid surface, the viscosity of the liquid prevents the metal nanoparticles from flying away from the liquid surface; removing the applied electric field, the microscopic morphology of the contact position between the metal nanoparticles and the liquid surface changes, the interfacial force on the metal nanoparticles is adjusted, the adhesion force between the metal nanoparticles and the liquid surface is overcome, so that the metal nanoparticles are stably maintained on the liquid surface without falling back into the liquid, and the rheology of the liquid is blocked to form a Pickering emulsion, thereby obtaining a metal-liquid composite microlens.

[0013] The super-resolution detection method based on the above-mentioned metal-liquid composite microlens is characterized by comprising the following steps: Step 1: adjusting the distance between the substrate and the surface of the object to be measured so that the metal-liquid composite microlens contacts the surface of the object to be measured, and observing with an optical microscope to obtain super-resolution imaging of the object to be measured; Step 2, moving the substrate left and right so that the metal-liquid composite microlens can monitor super-resolution imaging information of different parts of the object to be measured; Step 3, adjusting the electric field between the substrate of the metal-liquid composite microlens and the surface of the object to be measured, changing the morphology of the metal-liquid composite microlens, and realizing super-resolution imaging of objects to be measured with different complex structures; Step 4: Repeat steps 1 to 3 until a clear super-resolution imaging pattern is observed through the metal-liquid composite microlens.

[0014] Furthermore, in step 1, the distance between the metal-liquid composite microlens and the object to be measured meets the requirements of evanescent wave coupling transmission and the modulation requirements of spectrum continuation of the imaging system. A method for preparing a metal-liquid composite microlens is provided, comprising: Compared with the prior art, the present invention has at least the following beneficial technical effects: A metal-liquid composite microlens includes two layers of hemispherical liquid microlenses. A layer of metal nanoparticles is evenly arranged on the surface of the outer liquid microlens. The plasmon characteristics of the metal nanoparticles are used to enhance the super-resolution detection performance of the liquid microlens-assisted microscope.

[0015] A method for preparing a metal-liquid composite microlens, using nanoparticle liquid / liquid interface self-assembly and nanoparticle blocking technology to allow a two-layer liquid structure to approach a state of equilibrium, and by regulating the microlens morphology and nanoparticle arrangement through an external field, it is easy to achieve a uniform periodic arrangement of metal nanoparticles on the surface of the microlens, thereby preparing a metal-liquid composite microlens for super-resolution imaging, overcoming the difficulty of increasing a farther focal length in other super-resolution methods, and also overcoming the problems of uniform periodic arrangement of metal nanoparticles and unstable mechanical properties and weak self-healing properties of liquid microlenses. The present invention prepares a metal-liquid composite microlens that can meet the requirements of super-resolution detection imaging only through metal nanoparticle liquid-liquid interface self-assembly, nanoparticle blocking technology, uniform glue, uniform traction and pulling, and application of an external electric field. Compared with super-resolution fluorescence microscopy, this method does not require staining of samples or application of complex positioning algorithms; compared with structured light illumination microscopy, it does not require creation of complex structured light fields and can improve resolution; compared with surface plasmon super-resolution technology, this method does not require special dispersive materials, has less loss of imaging light waves, and is not limited by imaging contrast.

[0016] A super-resolution detection method for a metal-liquid composite microlens microscope based on nanoparticle liquid / liquid interface self-assembly and plugging technology, which controls the electric field force by adjusting the voltage, and then controls the arrangement of nanoparticles. The external field with spatial structure functionalization acts on the upper and lower sides to control the morphology of the microlens, and achieves precise positioning of the metal-liquid composite microlens for imaging complex and shaped samples, and obtains adaptive spatial morphology adjustment of micro-domain super-resolution imaging. Combined with the independent control of each metal-liquid composite microlens in the metal-liquid composite microlens array, super-resolution imaging of nano-shaped structures with large area and wide viewing angle is achieved. By regulating the microlens morphology and nanoparticle arrangement through external fields, it is very convenient to adjust the position of the metal nanoparticles on the surface of the metal-liquid composite microlens and the microscope objective lens, and realize super-resolution detection of other parts of the object; and by adjusting the voltage and the size of the gasket, the electric field force is regulated, and the final surface shape of the liquid microlens is manipulated to obtain the super-resolution detection of complex and shaped samples to match the metal-liquid composite microlens morphology characteristics, and realize the fast adaptive detection of three-dimensional nano / angstrom super-resolution of metal-liquid composite microlenses, and realize the highest matching of the spatial morphology of metal-liquid composite microlenses in super-resolution detection. This breaks through the limitations of traditional single spatial morphology characteristics on super-resolution detection.

[0017] Furthermore, by uniformly covering the surface of the liquid microlens with metal nanoparticles, the evanescent wave generated by the reflection of the nanostructure of the sample under test is easily coupled to the microlens. At the same time, the metal nanoparticles can produce plasmon effects, which makes it easier to achieve the modulation requirements of the spectrum extension of the imaging system, thereby significantly improving the super-resolution capability of the liquid microlens. Therefore, based on the evanescent wave coupling transmission theory and the plasmon local field enhancement effect, the influence of multiple parameters such as the spatial morphology of the metal-liquid composite microlens and the arrangement of nanoparticles on the interface on super-resolution imaging can be studied, so that the metal-liquid composite microlens can achieve optimal imaging detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the process flow of liquid microlens self-assembly; Figure 2 The figure is a schematic diagram of the self-assembly formation of liquid microlenses at the liquid-liquid interface, wherein the UV-curable adhesive film and the metal nanoparticles are half-section views; Figure 3 Schematic diagram of the particle blocking process and mechanical mechanism on the surface of metal-liquid composite microlens, where the UV-curable adhesive film and metal nanoparticles are half-section views, F1 is the interface force, and F2 is the adhesion force; Figure 4 The schematic diagram is a schematic diagram of the precise control of the morphological properties of the metal-liquid composite microlens, in which the UV-curable adhesive film and the metal nanoparticles are half-section views; Figure 5 The schematic diagram of super-resolution detection imaging before metal-liquid composite microlens regulation, in which the UV-curable adhesive film and metal nanoparticles are half-section views; Figure 6 This is a schematic diagram of super-resolution detection imaging after metal-liquid composite microlens regulation, in which the UV-cured adhesive film and metal nanoparticle parts are half-section views.

[0019] In the accompanying drawings: 1. micro-column template, 2. substrate, 3. UV-curing adhesive coating, 4. microporous structure, 5. propylene glycol solution, 6. beaker, 7. single-structure liquid microlens array, 8. UV-curing adhesive solution, 9. metal nanoparticles, 10. UV-curing adhesive film, 11. gasket, 12. electrode plate, 13. detector, 14. light wave, 15. eyepiece, 16. objective lens, 17. object to be measured. DETAILED DESCRIPTION

[0020] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0021] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0022] It should be noted that when an element is referred to as being "disposed on" another element, it may be directly on the other element or there may be another element centered thereon. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be another element centered thereon at the same time. The terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc. used herein indicate orientations or positional relationships based on the orientations or positional relationships 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 a limitation on the present invention.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0024] The present invention specifically relates to a method for preparing a metal-liquid composite microlens based on template-induced in-situ self-assembly and a super-resolution detection method.

[0025] Example 1 Reference Figure 1 and Figure 2 A metal-liquid composite microlens array comprises a substrate 2 and a curing adhesive coating 3 arranged on the substrate 2, wherein the UV curing adhesive coating 3 has one or more microholes arranged in an array form, each microhole contains a two-layer hemispherical liquid microlens, the inner layer of the liquid microlens is made of a glycerol solution 5, and the outer layer of the liquid microlens is made of a UV curing adhesive NOA 71 film, and metal nanoparticles 9 are uniformly covered on the UV curing adhesive NOA 71 film.

[0026] Example 2 A method for preparing a metal-liquid composite microlens comprises the following steps: Step 1: Use ICP etching to obtain a silicon micropore array as a template, pour polydimethylsiloxane (PDMS) on it, and after the PDMS is cured, peel off the microcolumn template 1 from the silicon wafer. The microcolumn template 1 is a PDMS microcolumn template.

[0027] Step 2, indium tin oxide ITO glass is selected as the substrate 2, and a layer of transparent UV-curable adhesive solution 8 is evenly spin-coated on the surface of the substrate to form a UV-curable adhesive coating 3, wherein the UV-curable adhesive solution 8 is a NOA 71 solution, and the UV-curable adhesive coating 3 is a NOA 71 coating; then, the micro-column template 1 prepared in step 1 is imprinted onto the substrate 2 containing the UV-curable adhesive coating 3 by using a micro-nano imprinting process, and after UV curing and peeling off PDMS, the silicon microporous structure 4 is transferred to the transparent UV-curable adhesive coating 3 to obtain a microporous structure 4.

[0028] Step 3: using octafluorocyclobutane (C4F8) to perform plasma treatment on the microporous structure 4 obtained in step 2, so as to make the microporous structure 4 hydrophobic.

[0029] Step 4: Place the hydrophobic microporous structure 4 prepared in step 3 into a beaker 6 containing a glycerol solution 5, and convert the Cassie-Baxter state where the glycerol solution 5 contacts the microporous structure 4 into a Wenzel state by liquid immersion and vacuum degassing.

[0030] Step 5: The hydrophobic microporous structure 4 is pulled and lifted at a uniform speed of 0.9 mm / min by a stepper motor. At the gas-liquid-solid three-phase interface formed by air, propylene glycol solution 5 and microporous structure 4, under the combined action of interfacial force and shear stress, the propylene glycol solution 5 is spontaneously assembled in the hydrophobic microporous structure 4 and forms a hemispherical shape, thereby obtaining a liquid microlens array 7 with a single structure.

[0031] Step 6: completely immerse the single-structure liquid microlens array 7 obtained in step 5 in the UV-curable adhesive solution 8 in which the metal nanoparticles 9 are uniformly dispersed, and pull the substrate 2 of the single-structure liquid microlens array 7 filled with the glycerol solution at a uniform speed of 0.9 mm / min by a stepper motor. The metal nanoparticles 9 are spread on the surface of the glycerol solution 5 along with the UV-curable adhesive solution 8 through interfacial forces and intermolecular interactions to form a UV-curable adhesive film 10, thereby obtaining a metal-liquid composite microlens array, wherein the UV-curable adhesive film 10 is a NOA 71 film.

[0032] Step 7: Reference Figure 6, add a plate 12 on top of the metal-liquid composite microlens array obtained in step 6, the plate 12 is made of indium tin oxide ITO glass, and add a spacer 11 of appropriate size between the substrate and the plate, the height of the spacer is slightly higher than the height of the metal-liquid composite microlens, and apply an optimal electric field, so that the metal nanoparticles 9 are gathered and closely arranged along the outer surface of the microlens. The optimal electric field is determined by the following process: by continuously adjusting the electric field, the magnitude of the electric field force is changed, and the electric field force is equal to the viscosity of the liquid, so that the metal nanoparticles 9 and the liquid are in a state of equilibrium, that is, the electric field force is equal to the viscosity of the liquid. Then, the voltage applied between the metal-liquid composite microlens array substrate 2 and the electrode plate 12 is removed, and the interface force between the metal nanoparticles 9 is adjusted by adjusting the voltage. The specific operation method is: when the voltage is removed, the electric field force is canceled, and the force balance of the metal nanoparticles 9 is broken. Under the action of the interface force, the balance is restored, so that the metal-liquid composite microlens has stable mechanical properties and self-healing properties, so that the metal-liquid composite microlens can realize the ease of operation of super-resolution detection and the transmission of large-field high-frequency information of the microlens and the modulation requirements of the spectrum of the imaging system.

[0033] like Figure 1 As shown, in step 1, the preparation process of the micro-column template 1 is as follows: Select silicon wafers with good flatness and finish. First, ultrasonically clean the silicon wafers in acetone, alcohol, and deionized water for 10 minutes to remove surface impurities. Then, evenly coat the photoresist (EPG 535, G-line) on a coating machine and pre-bake to form a photoresist layer. Next, perform exposure processing in a photolithography machine, so that ultraviolet light passes through the mask and irradiates the photoresist for 6 seconds to cause a chemical reaction of the photoresist. Then, use developer NaOH (0.5%) to develop for 30 seconds to remove the photoresist in the exposed part, forming a two-dimensional pattern of a micropore array, and perform high-temperature post-bake to enhance the stability of the photoresist. The silicon wafer with the photoresist mask was placed in the ICP etcher chamber, and SF6 and C4F8 gases were introduced after vacuuming. The gas flow rate of SF6 was 140 sccm and the gas flow rate of C4F8 was 70 sccm. The ICP power and RF power were adjusted for etching. The ICP power = 300W and the RF power = 100W. After the etching was completed, the silicon wafer was taken out, the photoresist was removed in acetone, and it was rinsed with deionized water and dried to obtain a silicon micropore array. On this basis, the silicon micropore array was used as a template, polydimethylsiloxane (PDMS) was poured, and it was heated at a temperature of 120℃-140℃ for 4h-6h to solidify to form a microcolumn array. By controlling the cooling rate of the PDMS core mold after solidification, a PDMS microcolumn template with good elasticity and transparency was prepared by demolding.

[0034] like Figure 1 As shown, in step 2, the stamping process is as follows: A UV-curable adhesive solution 8 is dripped onto a clean substrate 2, and a spin coating technique is used to evenly distribute the UV-curable adhesive coating 3. Then, the micro-column template 1 is imprinted onto the substrate 2 coated with the UV-curable adhesive coating 3, and the PDMS micro-column structure is accurately transferred to the UV-curable adhesive coating 3 by applying uniform pressure. Subsequently, the UV-curable adhesive coating 3 is exposed to UV light, so that the UV-curable adhesive solution 8 in the UV-curable adhesive coating 3 quickly changes from liquid to solid, forming a micro-nanostructure matching the micro-column template 1. Finally, the PDMS is carefully peeled off, leaving the UV-curable adhesive coating 3 with a silicon micropore array on the substrate 2, completing the successful transfer of the silicon micropore template to the UV-curable adhesive coating 3. The downward solid arrow indicates pressure.

[0035] like Figure 1 As shown, the hydrophobic treatment process of the microporous structure 4 in step 3 is as follows: The microporous structure 4 sample was placed in a dual-frequency capacitively coupled plasma treatment device. Then, octafluorocyclobutane (C4F8) gas was introduced and excited to generate plasma. By adjusting the parameters such as the power, time and gas pressure of the plasma treatment, the C4F8 was excited by the plasma to decompose and form a fluorinated carbon layer on the surface of the microporous structure 4 of the UV-curable adhesive 3. The microporous structure 4 sample was subjected to a precisely controlled hydrophobic treatment, so that the microporous structure 4 had hydrophobic properties. The high-frequency power of the plasma treatment was usually set to 600W, the low-frequency power was set to 120W; the treatment time was 90 s; and the gas pressure was 300 mTorr.

[0036] like Figure 1 As shown, in step 4, the microporous structure 4 is completely immersed in the glycerol solution 5; Use tweezers to carefully pick up the hydrophobic microporous structure 4 and place it in the glycerol solution 5 in the beaker 6 so that the microporous structure 4 is completely immersed in the glycerol solution 5; place the beaker 6 together with the microporous structure 4 in a vacuum box with a vacuum degree of 0.1 Pa for 10 min, and remove the bubbles in the micropores by vacuuming to ensure good contact between the liquid and the microporous structure 4. Finally, take the beaker 6 out of the vacuum chamber and restore the normal pressure condition. The glycerol solution 5 completely fills the inside of the microporous structure 4, and the infiltration state of the microporous structure 4 changes from the Cassie-Baxter state to the Wenzel state. During the process of liquid immersion and vacuum degassing, the surface state of the hydrophobic microporous structure 4 will change. Due to the effect of vacuum degassing, the contact area between the droplet and the microporous structure 4 increases, the air bubbles are removed, and the droplet is transformed from the Cassie-Baxter state to the Wenzel state, which is conducive to the regulation of the rheological deformation of the microlens by the interface force and shear force. In the Cassie-Baxter state, the droplets are supported by air bubbles and only contact the top of the microporous structure 4 ; in the Wenzel state, the droplets fill the gaps in the microporous structure 4 and contact the entire surface of the microporous structure 4 .

[0037] like Figure 1 As shown, in step 5, the liquid spontaneously assembles in the microporous structure 4 and forms a specific functional shape; The microporous structure 4 is pulled out of the substrate 2 vertically from the beaker 6 filled with glycerol solution 5 at a uniform speed of 0.9 mm / min by the lifting and traction of the stepper motor. When the microporous structure 4 reaches the solid-liquid-gas three-phase contact position, the liquid surface is triangular due to the Marangoni effect. As the microporous structure 4 is continuously lifted, the shear stress, viscosity and surface tension work together to cause liquid to remain in the micropores. When the micropores are about to be pulled out, the droplets in the micropores are still connected to the lower liquid surface due to the surface tension of the liquid. When the micropores are all pulled out, the shear stress at the non-micropores is 0, which is not enough to retain the droplets. Therefore, the droplets at the micropores are disconnected from the lower liquid surface, thereby forming a liquid microlens.

[0038] In step 6, the metal nanoparticles must be uniformly dispersed in the NOA71 solution; The metal nanoparticles are preferably Ag nanoparticles because they have a high refractive index, are easily available, and have a diameter that is usually no greater than 20 microns. For dispersing the nanoparticles, deionized water is selected as a solvent, which has high purity and contains fewer charged ions. These metal nanoparticles with a diameter of no more than 30 microns are placed in deionized water and subjected to ultrasonic oscillation treatment to ensure that the metal nanoparticles can be evenly dispersed in the NOA71 solution.

[0039] like Figure 2 As shown, the metal-liquid composite microlens array structure forming process in step 6 is as follows; The single-structure liquid microlens array 7 is placed into a liquid tank containing a UV-curable adhesive solution 8 doped with metal nanoparticles 9 at a speed of 1 mm / min, so that the UV-curable adhesive solution 8 completely immerses the single-structure liquid microlens array 7. Subsequently, in order to ensure the uniformity of the UV-curable adhesive film 10, the substrate 2 with the single-structure liquid microlens array 7 is pulled up at a very slow speed of 0.2 mm / min. The UV-curable adhesive solution 8 flows evenly over the surface of the single-structure liquid microlens array 7. Since the microporous structure 4 is treated with C4F8, the structure at the glycerol meniscus is hydrophilic, while the structure between the glycerol menisci is hydrophobic. Under the influence of surface tension, only the liquid layer of the UV-curable adhesive solution 8 doped with metal nanoparticles 9 is covered on the surface of the liquid lens array, and no UV-curable adhesive solution 8 doped with metal nanoparticles 9 is left between adjacent liquid microlenses. At the same time, due to the interfacial force and intermolecular action, the surface of the metal-liquid composite microlens still maintains a hemispherical shape.

[0040] like Figure 3 and Figure 4 As shown, the process of regulating the interface force and morphology characteristics of the metal-liquid composite microlens array structure in step 7 is as follows: The three-axis precision electrode system is used to drive the distance between the metal-liquid composite microlens plate 12 and the substrate 2, and an appropriate gasket 11 is added between the plate 12 and the substrate 2 and an optimized electric field is applied to drive the metal nanoparticles 9 to move along the interface toward the plate 12, and gather and arrange closely along the outer surface of the ultraviolet light curing glue solution 8. After the metal nanoparticles 9 move to the surface of the ultraviolet light curing glue solution 8, the viscosity of the liquid will prevent the metal nanoparticles 9 from flying away from the liquid surface. The voltage applied by the upper and lower plates of the metal-liquid composite microlens is removed, causing the microscopic morphology of the contact position between the metal nanoparticles 9 and the liquid surface to change, modulating the interfacial force on the metal nanoparticles 9, overcoming the adhesion between the metal nanoparticles 9 and the liquid surface, ensuring that the metal nanoparticles 9 remain stably on the liquid surface without falling back into the liquid, and blocking the rheology of the liquid to form a Pickering emulsion, thereby obtaining a metal-liquid composite microlens with stable mechanical properties and strong self-healing properties, so that the metal-liquid composite microlens can achieve the ease of operation of super-resolution detection and the transmission of high-frequency information of the microlens with a large field of view and the modulation requirements of the spectrum of the imaging system. By applying an appropriate strong voltage, the UV curing glue NOA 71 liquid will move in the direction of large electric field force, obtaining the electric field driven zoom process of the liquid microlens, and realizing the precise control of the morphological characteristics of the microlens. At the same time, a CCD camera is used to record and accurately track the surface shape changes of the liquid microlens. By adjusting the voltage and the size of the gasket 11, the electric field force is regulated and the final morphology of the metal-liquid composite microlens is manipulated to match the requirements of the super-resolution detection of complex and shaped samples for the morphological characteristics of the metal-liquid composite microlens.

[0041] The microscope super-resolution detection method based on metal-liquid composite microlens assistance includes the following steps: Step 1: Use a three-axis precision electrode system to adjust the distance between the substrate 2 of the metal-liquid composite microlens and the surface of the object to be measured 17, so that the metal-liquid composite microlens contacts the surface of the object to be measured 17, adjust the distance between the metal-liquid composite microlens and the surface of the object to be measured 17, so that the distance meets the requirements of evanescent wave coupling transmission and the modulation requirements of the spectrum extension of the imaging system, and observe using an optical microscope to obtain super-resolution imaging of the object to be measured. ; Step 2, moving the substrate 2 left and right so that the metal-liquid composite microlens can monitor super-resolution imaging information of different parts of the object to be measured 17; Step 3, adjusting the electric field between the substrate 2 of the metal-liquid composite microlens and the surface of the object to be measured 17, changing the shape of the metal-liquid composite microlens, and realizing super-resolution imaging of the object to be measured 17 with different complex structures; Step 4: Repeat steps 1 to 3 until a clear super-resolution imaging pattern is observed through the metal-liquid composite microlens.

[0042] like Figure 5 As shown, in step 1, the metal liquid microlens needs to be in close contact with the surface of the object to be measured and observed using an optical microscope. The light wave 14 is emitted from the object to be measured, modulated by the metal-liquid composite microlens, and amplified by the eyepiece 15 to form a clear super-resolution image, while the detector 13 is located at the top and is used to receive and detect the light wave processed by the optical system.

[0043] The distance between the substrate 2 of the metal-liquid composite microlens and the surface of the object to be measured 17 is adjusted by using a three-axis precision electrode system, so that the object to be measured 17 is in contact with the metal-liquid composite microlens. The distance between the metal-liquid composite microlens and the object to be measured must meet the requirements of evanescent wave coupling transmission, generally less than 10μm, and placed in a vacuum environment so that the metal-liquid composite microlens is sufficiently and tightly attached to the surface of the object to be measured.

[0044] Adjust the left and right position of the objective lens 16 to ensure that the objective lens 16 is directly aimed at the metal nanoparticles 9 in the metal-liquid composite microlens. Through this vertical illumination method, the metal nanoparticles can more effectively capture the evanescent wave, enhance the propagation efficiency, and expand the spectral range of the imaging system. The metal nanoparticles focus the light to a farther focal point f=nr / 2(nn s ) . Where n and n s represent the refractive index of the metal nanoparticles and their external medium, respectively. rNext, adjust the objective lens up and down until the microscope displays the clearest image, which means that the aperture angle between the objective lens 16 and the object to be measured reaches the maximum value. , the numerical aperture of objective lens 16 is the largest, ,in NA is the numerical aperture of the objective lens 、 n is the refractive index between the objective lens and the object to be measured, ɑ is the aperture angle between the objective lens and the object to be measured, and the minimum distance between two object points that can be distinguished in the microscope reaches the minimum value. , is the wavelength of the light source, so that ultrafine structures <50nm on the object can be distinguished in theory.

[0045] In the step 2, the substrate 2 is moved left and right to adjust the position of the metal-liquid composite microlens, so that the metal-liquid composite microlens can monitor the super-resolution imaging information of different parts of the object to be measured 17, thereby monitoring the super-resolution imaging information of different parts of the object; In step 3, the electric field between the substrate 2 of the metal-liquid composite microlens and the surface of the object to be measured 17 is adjusted to change the shape of the metal-liquid composite microlens, thereby changing the effect of the liquid microlens super-resolution imaging to suit the distance between the liquid microlens and the object to be measured, thereby achieving different super-resolution effects of the microlens.

[0046] Repeat steps 1-3 to find a clear super-resolution image of the object to be tested.

[0047] The present invention can easily realize uniform periodic arrangement of metal nanoparticles, thus solving the difficult problem of uniform periodic arrangement of metal nanoparticles; realize localized super-resolution detection of objects by adjusting the position of metal-liquid composite microlenses; realize micro-control of object monitoring performance by adjusting the size of the electric field between the electrode plate and the substrate and changing the spatial form of the metal-liquid composite microlenses; the present invention has a simple process, solves the problems of poor mechanical stability and weak self-healing property of liquid microlenses, and realizes real-time localized super-resolution measurement of nanometers / angstroms on complex special-shaped structures.

[0048] The term "consisting of" describing a combination shall include the identified elements, ingredients, parts or steps and other elements, ingredients, parts or steps that do not substantially affect the basic novel characteristics of the combination. The use of the terms "comprising" or "including" to describe a combination of elements, ingredients, parts or steps herein also contemplates embodiments that consist essentially of these elements, ingredients, parts or steps. By using the term "may", it is intended to illustrate that any of the attributes described that "may" be included are optional.

[0049] Multiple elements, ingredients, parts or steps can be provided by a single integrated element, ingredient, part or step. Alternatively, a single integrated element, ingredient, part or step can be divided into separate multiple elements, ingredients, parts or steps. The disclosure "one" or "an" used to describe an element, ingredient, part or step is not intended to exclude other elements, ingredients, parts or steps.

[0050] It should be understood that the above description is for illustration and not for limitation. Many embodiments and many applications beyond the examples provided will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of the present teachings should not be determined with reference to the above description, but rather with reference to the foregoing claims and the full scope of equivalents to which such claims are entitled. For the purpose of comprehensiveness, all articles and references, including disclosures of patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the foregoing claims is not intended to be a waiver of such subject matter, nor should it be considered that the applicant has not considered such subject matter to be part of the disclosed inventive subject matter.

Claims

1. A metal-liquid composite microlens, characterized in that: The invention comprises a substrate (2) and an ultraviolet light curing adhesive coating (3) arranged on the substrate (2), wherein the ultraviolet light curing adhesive coating (3) has one or more micropores arranged in an array form, wherein the micropores are filled with a glycerol solution (5), and a two-layer hemispherical liquid microlens is provided on the top of the micropores, wherein the inner layer of the liquid microlens is made of the glycerol solution (5), and the outer layer of the liquid microlens is an ultraviolet light curing adhesive film (10), and the ultraviolet light curing adhesive film (10) is covered with metal nanoparticles (9).

2. The metal-liquid composite microlens according to claim 1, characterized in that: The UV-curing adhesive coating (3) is UV-curing adhesive NOA71.

3. The metal-liquid composite microlens according to claim 1, characterized in that: The substrate (2) is indium tin oxide (ITO) glass.

4. The method for preparing a metal-liquid composite microlens according to claim 1, characterized in that: The following steps are involved: Step 1, preparing a micro-column template (1); Step 2, preparing a UV-curable adhesive coating (3) on the surface of the substrate (2), then imprinting the micro-column template (1) obtained in step 1 onto the UV-curable adhesive coating (3), curing the UV-curable adhesive coating (3), and peeling off the micro-column template (1) to obtain a microporous structure (4), wherein the microporous structure (4) is a UV-curable adhesive coating (3) having a plurality of micropores; Step 3, performing plasma treatment on the microporous structure (4) obtained in step 2 to make the microporous structure (4) hydrophobic; Step 4, placing the hydrophobic microporous structure (4) prepared in step 3 into a container containing a glycerol solution (5), and converting the Cassie-Baxter state in which the glycerol solution (5) contacts the microporous structure (4) into a Wenzel state by liquid immersion and vacuum degassing; Step 5, the hydrophobic microporous structure (4) is pulled and lifted at a uniform speed, and at the gas-liquid-solid three-phase interface formed by air, propylene glycol solution (5) and microporous structure (4), under the combined action of interfacial force and shear stress, the propylene glycol solution (5) is spontaneously assembled in the hydrophobic microporous structure (4) to form a hemispherical film, thereby obtaining a single-layer liquid microlens array (7); Step 6, immersing the single-layer liquid microlens array (7) obtained in step 5 in a UV-curable adhesive solution (8) in which metal nanoparticles (9) are uniformly dispersed, and then pulling the substrate (2) having the single-layer liquid microlens array (7), so that the metal nanoparticles (9) are spread on the surface of the glycerol solution (5) along with the UV-curable adhesive solution (8) through interfacial forces and intermolecular interactions, forming a UV-curable adhesive film (10) containing the metal nanoparticles (9), and obtaining a metal-liquid composite microlens array; Step 7, adding an electrode plate (12) above the metal-liquid composite microlens array obtained in step 6, adding a gasket (11) between the substrate (2) and the electrode plate (12), and applying an electric field to bring the metal nanoparticles and the liquid into a state of equilibrium, so that the metal nanoparticles (9) are gathered and arranged along the outer surface of the liquid microlens; then removing the applied voltage, adjusting the interfacial force between the metal nanoparticles (9), so that the nanoparticles are stably maintained on the liquid surface and do not fall back into the liquid.

5. The method for preparing a metal-liquid composite microlens according to claim 4, characterized in that: The specific process of step 2 is: evenly spin-coating a layer of ultraviolet curing adhesive solution (8) on the surface of the substrate (2) to form an ultraviolet curing adhesive coating (3), covering the ultraviolet curing adhesive coating (3) with a micro-column template (1) and applying uniform pressure, then curing the ultraviolet curing adhesive coating (3) by ultraviolet irradiation, peeling off the micro-column template (1), and obtaining a microporous structure (4).

6. The method for preparing a metal-liquid composite microlens according to claim 4, characterized in that: The specific process of step 3 is: introducing C4F8 as a fluorine source into the plasma reaction chamber, exciting C4F8 by plasma, causing it to decompose and form a fluorinated carbon layer on the surface of the microporous structure (4), so that the microporous structure (4) has a hydrophobic property.

7. The method for preparing a metal-liquid composite microlens according to claim 4, characterized in that: The specific process of step 4 is as follows: placing the hydrophobic microporous structure (4) in a container containing the glycerol solution (5) and immersing it, then placing the container containing the glycerol solution (5) and the microporous structure (4) in a vacuum chamber, removing the bubbles in the microporous structure (4) by vacuuming, and finally taking the container out of the vacuum chamber, so that the glycerol solution (5) completely fills the interior of the microporous structure (4), and the infiltration state of the microporous structure (4) changes from the Cassie-Baxter state to the Wenzel state.

8. The method for preparing a metal-liquid composite microlens according to claim 4, characterized in that: The specific process of step 7 is as follows: adding a plate (12) above the metal-liquid composite microlens array obtained in step 6, adjusting the distance between the metal-liquid composite microlens plate (12) and the substrate (2), adding a gasket (11) between the plate (12) and the substrate (2) and applying an electric field to drive the metal nanoparticles (9) to move toward the interface in the direction of the plate (12), and to gather and arrange along the outer surface of the microlens; after the metal nanoparticles (9) move to the liquid surface, the viscosity of the liquid prevents the metal nanoparticles (9) from flying away from the liquid surface; removing the applied electric field, the microscopic morphology of the contact position between the metal nanoparticles (9) and the liquid surface changes, adjusting the interfacial force on the metal nanoparticles (9), overcoming the adhesion between the metal nanoparticles (9) and the liquid surface, so that the metal nanoparticles (9) are stably maintained on the liquid surface without falling back into the liquid, and blocking the rheology of the liquid to form a Pickering emulsion, thereby obtaining a metal-liquid composite microlens.

9. The super-resolution detection method based on the metal-liquid composite microlens according to claim 1, characterized in that: The following steps are involved: Step 1: adjusting the distance between the substrate (2) and the surface of the object to be measured (17) so that the metal-liquid composite microlens contacts the surface of the object to be measured (17), and observing with an optical microscope to obtain super-resolution imaging of the object to be measured; Step 2, moving the substrate (2) left and right so that the metal-liquid composite microlens can monitor super-resolution imaging information of different parts of the object to be measured (17); Step 3, adjusting the electric field between the substrate (2) of the metal-liquid composite microlens and the surface of the object to be measured (17), changing the morphology of the metal-liquid composite microlens, and realizing super-resolution imaging of the object to be measured (17) with different complex structures; Step 4: Repeat steps 1 to 3 until a clear super-resolution imaging pattern is observed through the metal-liquid composite microlens.

10. The super-resolution detection method based on metal-liquid composite microlens assisted microscope according to claim 9, characterized in that: In the step 1, the distance between the metal-liquid composite microlens and the object to be measured (17) meets the requirements of evanescent wave coupling transmission and the modulation requirements of spectrum extension of the imaging system.

Images