Optimization method for liquid lens power boost

Abstract

This invention discloses an optimization method for improving the optical power of a liquid lens, belonging to the field of liquid lenses. Specifically, it includes: (1) screening reagents using a material property database, selecting polyelectrolytes and their mixed electrolytes, and preparing polyelectrolyte mixture solutions with different blending ratios; (2) extracting the fluid viscosity data of all combined liquids through viscosity experiments; (3) extracting the spectral data of the characteristic group of liquids through Raman spectroscopy experiments; (4) measuring the electrowetting effect of all combined liquids using an electrowetting contact angle measurement method, and analyzing and selecting the optimal liquid combination based on the viscosity and spectral data; (5) using the optimal liquid combination to fabricate a liquid lens and measuring its optical power data within a continuous voltage range. Through the above optimization method, this invention obtains a high-performance conductive liquid for electrowetting liquid lenses, ultimately achieving an optimal liquid lens with a large optical power tuning range and a small driving voltage.

Description

Technical Field

[0001] This invention belongs to the field of liquid lenses, and more specifically, relates to an optimized method for improving the optical power of liquid lenses. Background Technology

[0002] Optical systems are increasingly moving towards lightweight and integrated designs, and liquid lenses, with their tunable focal length, have been widely researched and applied in the field of optical devices. Liquid lenses use liquid as the optical material, achieving focal length tunability by changing the curvature of the liquid surface, thus making the structure of the optical system simpler and lighter.

[0003] With the development of imaging technology, the demand for tunable optical devices with high optical power and small size has increased significantly in applications such as optical microscopy and biomedicine. To achieve functional integration and rapid adjustment, electrowetting liquid lenses are often used, offering advantages such as fast response speed and small size. However, they struggle to meet the demands for high optical power. Furthermore, the commonly used conductive liquids in electrowetting liquid lenses are currently saline solutions and similar simple electrolyte solutions. Liquid lenses composed of these liquids typically cannot achieve high optical power, hindering their further application. Therefore, in-depth research on high-power liquid lenses and their materials is essential, as it will benefit the further development and application of miniaturized and lightweight optical systems. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide an optimized method for improving the optical power of liquid lenses based on polyelectrolyte mixture solutions. The method is intended to formulate and select high-performance conductive liquids for liquid lenses, thereby obtaining electrowetting liquid lenses with a large optical power tuning range and a small driving voltage.

[0005] To achieve the above objectives, the present invention provides an optimized method for improving the optical power of a liquid lens, comprising the following steps:

[0006] (1) Using a material property database, the required drugs for the mixture are screened, namely polyelectrolytes and electrolytes mixed with them. Under a fixed solute fraction, multiple polyelectrolyte mixture solutions with different blending ratios are prepared by changing the relative proportions of the mixture.

[0007] (2) Through viscosity measurement experiments, extract and analyze the fluid viscosity data of the polyelectrolyte mixture solutions of all the above combinations at high shear rates;

[0008] (3) Extract and analyze the spectral data of liquids with characteristic ratios in all combinations through laser Raman spectroscopy experiments;

[0009] (4) Using the electrowetting contact angle measurement method, the electrowetting effect of all liquid combinations is measured, and the viscosity and spectral data are combined for comprehensive analysis to select the optimal liquid combination and measure its optical properties.

[0010] (5) Use the selected optimal liquid combination to make an electrowetting liquid lens and measure its optical power data.

[0011] Beneficial effects: Through the above-mentioned optimization method and multidisciplinary experiments, this invention has verified that polyelectrolyte mixture solution as a conductive liquid can improve the optical power performance of electrowetting liquid lens. The optimal polyelectrolyte mixture solution and its corresponding ratio range were obtained through the above optimization, and finally an electrowetting liquid lens with a large optical power tuning range and small driving voltage was obtained.

[0012] Preferably, in the process of preparing a polyelectrolyte mixture solution using pharmaceuticals, the polyelectrolyte mixture solution needs to contain at least one polyelectrolyte and one to five electrolytes mixed therewith.

[0013] Preferably, the fluid parameters involved in the multidisciplinary experimental approach used to verify the properties of the liquid include: viscosity, spectral data, and contact angle.

[0014] Preferably, in the viscosity test, all combinations of liquids are taken within 10~100s. -1 The average viscosity within the high shear rate range is used as the fluid viscosity data.

[0015] Preferably, in the spectral experiment, the selected liquids in each characteristic ratio group need to have a polyelectrolyte content difference of not less than 5%, and the spectral data of the liquids are obtained by laser Raman spectrometer under the excitation band of 488~633nm.

[0016] Preferably, a mixed solution of ammonium polyphosphate and potassium chloride is selected as the conductive liquid of the liquid lens. The mass fraction of ammonium polyphosphate in the conductive liquid is not less than 10%, and the total mass fraction of ammonium polyphosphate and potassium chloride is 20%. The insulating liquid of the liquid lens is colorless and transparent silicone oil. The insulating liquid and the conductive liquid are immiscible and have matching densities.

[0017] Beneficial effects: The selection of conductive liquid for liquid lenses not only takes into account the influence of the fluid's density, transmittance, refractive index and Abbe number, but also comprehensively considers the fluid's macroscopic viscosity properties, microscopic spectral performance and electrowetting contact angle. This allows the optimal liquid combination obtained through optimization to produce a more obvious electrowetting phenomenon while having excellent optical performance.

[0018] Preferably, a low-polymerization-degree polyelectrolyte and a small-molecule metal electrolyte are selected for aqueous phase blending. The total solute mass fraction and different blending ratios are set according to actual experiments to prepare the blend. The solution properties are characterized at the macroscopic and microscopic levels by viscosity and spectroscopy. The material with the optimal electrowetting effect is selected by comprehensive analysis using the electrowetting contact angle data.

[0019] Beneficial effects: For polyelectrolyte materials with different properties, the optimal blending solution corresponding to different polyelectrolyte materials can be obtained by changing the total solute mass fraction, the relative proportion of blending reagents, or the material combination of blending reagents, making the optimization method have excellent universality.

[0020] Compared with the prior art, the above technical solutions proposed in this invention can achieve the following beneficial effects.

[0021] 1. The optimization method for improving the optical power of liquid lenses based on polyelectrolyte mixture solutions provided by the present invention verifies through multidisciplinary experiments that polyelectrolyte mixture solutions, as conductive liquids, can improve the optical power performance of electrowetting liquid lenses, and the optimal polyelectrolyte mixture solution and its ratio range are obtained through the above optimization.

[0022] 2. The optimization method for improving the optical power of a liquid lens based on a polyelectrolyte mixture solution provided by the present invention takes into account not only the influence of the fluid's density, transmittance, refractive index and Abbe number, but also the macroscopic viscosity properties and microscopic spectral performance of the fluid, so that the optimal liquid combination obtained by optimization has excellent optical performance and is easy to drive.

[0023] 3. The optimization method for improving the optical power of a liquid lens based on a polyelectrolyte mixture solution provided by the present invention takes into account not only the influence of the fluid's density, transmittance, refractive index and Abbe number, but also the size of the electrowetting contact angle of the fluid. This makes the optimal liquid combination obtained by optimization able to produce a more obvious electrowetting phenomenon and meet the needs of practical applications.

[0024] 4. The optimization method for improving the optical power of liquid lenses based on polyelectrolyte mixture solutions provided by this invention can obtain the optimal conductive liquid material for liquid lenses applicable to different types of materials by selecting different blended electrolyte materials, changing the relative proportion of blended drugs and increasing the amount of blended electrolytes, thus making the optimization method have excellent universality. Attached Figure Description

[0025] Figure 1 This is a flowchart illustrating the optimized method for improving the optical power of a liquid lens based on a polyelectrolyte mixture solution provided by the present invention.

[0026] Figure 2 The images show the Raman spectra of liquids 1, 5, and 7 at an excitation wavelength of 532 nm in the spectral experiment.

[0027] Figure 3 This is a schematic diagram of the initial contact angle and the contact angle after applying current in an electrowetting effect experiment.

[0028] Figure 4 This is a three-dimensional cross-sectional structural diagram of the liquid lens provided by the present invention.

[0029] Figure 5 This is a schematic diagram of the liquid surface of the liquid lens provided by the present invention when no power is applied.

[0030] Figure 6 This is a schematic diagram of the liquid surface profile of the liquid lens provided by the present invention after applying voltage.

[0031] Figure 7 A line graph comparing the optical power of the liquid lens and a conventional liquid lens provided by this invention.

[0032] Figure 8 The transmittance spectrum of the optimal polyelectrolyte mixture solution provided by the present invention in the visible light band (400~800nm).

[0033] Figure 9 The transmittance spectrum of the optimal polyelectrolyte mixture solution provided by the present invention in the 200~1400nm wavelength range. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of the invention described below can be combined with each other as long as they do not conflict with each other.

[0035] The performance of electrowetting liquid lenses is mainly related to the type of conductive liquid material and its corresponding comprehensive physicochemical properties. Therefore, this invention proposes an optimized method for improving the optical power of liquid lenses based on polyelectrolyte mixture solutions, such as... Figure 1 As shown, it includes the following steps:

[0036] (1) The required drugs for the mixture are screened by using the material property database, namely polyelectrolytes and electrolytes mixed with them. The relative proportions of the mixture are changed under a fixed solute fraction and several groups of polyelectrolyte mixture solutions with different blending ratios are prepared. Taking ammonium polyphosphate and potassium chloride as an example, all the liquid combinations prepared are shown in Table 1.

[0037] Table 1

[0038] Liquid combination index value Mass of ammonium polyphosphate (g) Potassium chloride mass (g) Volume of distilled water (mL) 1 0.25 1.75 8.00 2 0.50 1.50 8.00 3 0.75 1.25 8.00 4 1.00 1.00 8.00 5 1.25 0.75 8.00 6 1.50 0.50 8.00 7 1.75 0.25 8.00

[0039] (2) Viscosity was measured and extracted from all combinations of liquids at high shear rates (10~100s) using a modular intelligent rotational rheometer. -1 The viscosity of the liquid was measured as a function of shear rate, and the average viscosity within that rate range was calculated as the fluid viscosity data for evaluating the liquid viscosity. The calculation results are shown in Table 2.

[0040] Table 2

[0041] Liquid combination index value 1 2 3 4 5 6 7 Average viscosity (mPa·s) 1.035 1.065 1.142 1.304 1.316 1.412 1.425

[0042] (3) Spectral data were extracted using a laser Raman spectrometer. Characteristic ratio groups were selected from all liquid combinations for measurement. The selected characteristic ratio groups required a polyelectrolyte content difference of no less than 5%. Liquids 1, 5, and 7 from the above liquid combinations were selected as characteristic ratio groups for Raman spectroscopy measurement. The Raman spectra of the three characteristic ratio groups were then compared and analyzed. Figure 2 As shown, the excitation wavelength used in this embodiment is 532nm;

[0043] (4) Using the electrowetting contact angle measurement method, all combined liquids were treated as conductive liquids to measure the electrowetting effect. The optimal liquid combination was then selected by combining viscosity and spectral data for comprehensive analysis. Initially, the initial contact angle θ0 of each conductive liquid was 165°. After applying the same voltage, the contact angle θ of each conductive liquid decreased due to the electrowetting effect. The angle change is illustrated in the diagram below. Figure 3 As shown in Table 3, the contact angle θ of all liquid combinations after applying an 80VrmsDC (50Hz) sinusoidal signal is shown in Table 3. Based on the contact angle after energization and the above data on viscosity and spectrum, the optimal polyelectrolyte mixture solution can be selected. The specific ratio range is: the mass fraction of ammonium polyphosphate in the mixture solution is not less than 10%, and the total mass fraction of ammonium polyphosphate and potassium chloride is 20%.

[0044] Table 3

[0045] Liquid combination index value 1 2 3 4 5 6 7 The contact angle θ (°) after power is applied. 79 75 70 62 63 63 62

[0046] (5) The optimal polyelectrolyte mixture solution selected above was used to make an electrowetting liquid lens, and its optical power data in the continuously changing voltage range (0~45V) was measured by a focimeter, as shown in Table 4.

[0047] Table 4

[0048] Voltage (V) 0 10 15 20 25 30 35 40 45 Optical power (D) -37.97 -37.66 -33.09 -26.96 -17.78 -9.19 0.67 9.36 18.71

[0049] The structure of the liquid lens is as follows: Figure 4 As shown, the structure consists of 1. Window glass, 2. Filling liquid I, 3. Filling liquid II, 4. Lens cavity, 5. Extension electrode, and 6. Cavity electrode. The lens is 5.75 mm long, 11 mm in diameter, and has an effective aperture of 6.4 mm. The lens cavity and cavity electrode are coaxial with the center of the liquid-liquid surface. The upper part of the lens cavity and the lower part of the cavity electrode are both circular window glass, 8 mm in diameter and 0.8 mm thick. The two sets of externally symmetrical extension electrodes have lengths, widths, and thicknesses of 1.5 mm, 1.2 mm, and 0.5 mm, respectively. The lens cavity is 4.45 mm long, has an outer diameter of 11 mm, and its inner wall is cylindrical with a diameter of 6.4 mm. The cavity electrode is connected to the bottom of the lens cavity and has a length of 1.3 mm, an outer diameter of 11 mm, and an inner diameter of 6.4 mm. The lens cavity is filled with two immiscible liquids with matched densities. Filling liquid I is a colorless, transparent silicone oil with a refractive index of 1.556 and an Abbe number of 39, located in the upper layer. Filler liquid II is the selected optimal polyelectrolyte mixture solution, colorless and transparent, with a refractive index of 1.362 and an Abbe number of 46, serving as the lower conductive liquid. The density of both filler liquid I and filler liquid II is 1.15 g / cm³. 3 This liquid lens is an electrowetting mechanism liquid lens. It achieves tunable optical power by altering the curvature of the liquid-liquid surface formed between two immiscible liquids using voltage. The liquid surface shapes before and after applying voltage are shown below. Figure 5 , 6 As shown.

[0050] To verify the beneficial effects of the optimization method provided by this invention, a liquid lens made from the optimized polyelectrolyte mixture solution was compared with a conventional liquid lens made from sodium chloride solution in terms of optical power performance. The only difference between the two liquid lenses is the type of conductive liquid. Figure 7 The graph shows a line graph comparing the optical power of the two types of liquid lenses. Sodium chloride solution and other simple electrolyte solutions are commonly used materials in conventional electrowetting liquid lenses. It can be seen that the liquid lens based on the polyelectrolyte mixture solution optimized in this invention has a significant improvement in optical power and driving force performance compared to the liquid lens based on sodium chloride solution. The minimum driving voltage for the liquid lens based on sodium chloride solution is 20V, while the liquid lens based on the polyelectrolyte mixture solution can be driven at a low voltage of 10V. The light transmittance test results of the optimized polyelectrolyte mixture solution show that this solution has a high transmittance (≥89%) in the visible light band (400~800nm), specifically as shown below. Figure 8As shown, this solution material can be well applied in the field of optical imaging. Furthermore, as... Figure 9 As shown, the transmittance spectrum in the 200~1400nm band proves that this material can also have specific applications in the near-infrared band.

[0051] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An optimized method for improving the optical power of a liquid lens, characterized in that, Includes the following steps: (1) Using a material property database, the required drugs for the mixture are screened, namely polyelectrolytes and electrolytes mixed with them. Under a fixed solute fraction, multiple polyelectrolyte mixture solutions with different blending ratios are prepared by changing the relative proportions of the mixture. (2) Through viscosity measurement experiments, extract and analyze the fluid viscosity data of the polyelectrolyte mixture solutions of all the above combinations at high shear rates; (3) Extract and analyze the spectral data of liquids with characteristic ratios in all combinations through laser Raman spectroscopy experiments; (4) Using the electrowetting contact angle measurement method, the electrowetting effect of all liquid combinations is measured, and the viscosity and spectral data are combined for comprehensive analysis to select the optimal liquid combination and measure its optical properties. (5) Use the selected optimal liquid combination to make an electrowetting liquid lens and measure its optical power data.

2. The optimized method for improving the optical power of a liquid lens according to claim 1, characterized in that, In step (1), the polyelectrolyte mixture solution must contain at least one polyelectrolyte and one to five electrolytes mixed therewith.

3. The optimized method for improving the optical power of a liquid lens according to claim 1, characterized in that, In step (2), the fluid viscosity data is the viscosity of all combinations of liquids in the range of 10~100 s. -1 The average viscosity within the high shear rate range.

4. The optimized method for improving the optical power of a liquid lens according to claim 1, characterized in that, In step (3), the selected characteristic ratio groups of liquids must have a polyelectrolyte content difference of not less than 5%.

5. The optimized method for improving the optical power of a liquid lens according to claim 1, characterized in that, In step (4), the optimal polyelectrolyte mixture solution is selected by using electrowetting effect, viscosity and spectral properties as comprehensive performance evaluation indicators. Ammonium polyphosphate and potassium chloride are selected as blending agents. The mass fraction of ammonium polyphosphate in the optimal polyelectrolyte mixture solution is not less than 10%, and the total mass fraction of ammonium polyphosphate and potassium chloride is 20%.

6. The optimized method for improving the optical power of a liquid lens according to claim 4, characterized in that, The spectral data of the liquids in the characteristic proportion group were obtained by laser Raman spectroscopy at an excitation wavelength of 488~633nm.

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