Speckle particle preparation system and method

Abstract

The invention relates to the technical field of speckle preparation equipment, and provides a speckle particle preparation system and a method thereof.According to the method, liquid pigment is gathered at an outlet of a liquid drop generation device through the liquid drop generation device to form liquid drops instead of being directly sprayed out, the liquid drop generation device is conductive and is connected with a first pole of a high-voltage generator, and the high-voltage generator is connected with a second pole of the high-voltage generator; under the condition that the high-voltage generator applies voltage, a high-voltage electric field can be formed between an outlet of the liquid drop generation device and the conductive device, liquid drops are enriched with charges of the same polarity under the action of the high-voltage electric field, and after the charges of the same polarity in the liquid drops are enriched to a certain degree, the surface tension of the liquid drops cannot overcome the mutual exclusion electric field force between the charges of the same polarity; the liquid drops are atomized and broken to form fine spray, so that speckle particles which are uniformly distributed are formed on the surface of the sample to be detected.

Description

Technical Field

[0001] This application relates to the field of speckle particle preparation equipment technology, and in particular to a speckle particle preparation system and method thereof. Background Technology

[0002] Speckle patterns are randomly distributed bright or dark spots that form unique patterns on the surface of a sample. These patterns change as the sample deforms or flows. By analyzing the changes in the speckle pattern on the sample surface before and after deformation or flow, the deformation, displacement, or flow velocity of the sample can be determined.

[0003] The most common method for preparing speckle patterns is manual spraying, where personnel use handheld spray paint or other speckle-making equipment to manually spray the surface of the sample. This method may result in uneven distribution of speckles on the sample surface, with some areas being dense and others sparse. This uneven distribution of speckles can lead to difficulties in uniformly tracking the deformation of the entire surface or the flow of the sample during subsequent analysis, thus affecting the accuracy and reliability of the measurement results. Summary of the Invention

[0004] This application provides a speckle particle preparation system and method, which can form uniformly distributed speckle particles on the surface of the sample to be tested.

[0005] To achieve the above objectives, this application adopts the following technical solution:

[0006] In a first aspect, a speckle particle preparation system is provided, comprising: a storage tank for storing liquid pigment; a conductive droplet generating device, the inlet of which is connected to the outlet of the storage tank, the droplet generating device being used to gather the liquid pigment at the outlet of the droplet generating device to form droplets; a high-voltage generator and a conductive device, the first electrode of the high-voltage generator being connected to the droplet generating device, the second electrode of the high-voltage generator being connected to the conductive device, the high-voltage generator being used to apply voltage to form a high-voltage electric field between the droplet generating device and the conductive device, the droplets being atomized under the action of the high-voltage electric field; and a stage facing the outlet of the droplet generating device, the stage being used to hold the sample to be tested, the droplets being atomized to form speckle particles on the surface of the sample to be tested.

[0007] In this embodiment, liquid pigment is gathered into droplets at the outlet of the droplet generating device instead of being directly sprayed out. The droplet generating device is conductive and connected to the first pole of a high-voltage generator. When a voltage is applied, the high-voltage generator can form a high-voltage electric field between the outlet of the droplet generating device and the conductive device. Under the action of the high-voltage electric field, the droplets accumulate like charges. After the like charges in the droplets accumulate to a certain extent, the surface tension of the droplets will be unable to overcome the mutual repulsion electric field force between like charges, and the droplets will atomize and break up to form a fine spray, thereby forming uniformly distributed speckled particles on the surface of the sample to be tested.

[0008] In one possible implementation of the first aspect, the system further includes an injection pump connected between the outlet of the liquid storage tank and the inlet of the droplet generating device, the injection pump being used to control the droplet aggregation rate of the liquid pigment at the outlet of the droplet generating device. In this embodiment, by controlling the droplet aggregation rate of the liquid pigment at the outlet of the droplet generating device and the voltage of the high-voltage electric field, the size of the droplets during atomization can be controlled, thereby controlling the size of the speckle particles formed after atomization, enabling the preparation of speckle particles with controllable size and uniform distribution.

[0009] In one possible implementation of the first aspect, the droplet generating device includes a syringe and a conductive needle. The inlet of the syringe is connected to the outlet of the injection pump, and the outlet of the syringe is connected to the inlet of the conductive needle. The syringe and the conductive needle are used to gather the liquid pigment at the outlet of the conductive needle to form droplets. This application provides an implementation of a droplet generating device.

[0010] In one possible implementation of the first aspect, the injection pump controls the droplet aggregation rate of the liquid pigment at the outlet of the droplet generating device to be between 5 μL / min and 25 μL / min, and the voltage applied by the high-voltage generator is between 5 kV and 25 kV. In this embodiment, through the above limitations, the size of the droplets during atomization can reach approximately several millimeters, and the particle size of the speckle particles formed after droplet atomization can reach several micrometers or even a fraction of a micrometer, thus realizing the preparation of tiny speckle particles.

[0011] In one possible implementation of the first aspect, the particle size of the speckle particles is between 0.5 μm and 3 μm.

[0012] In one possible implementation of the first aspect, the injection pump controls the droplet aggregation rate of the liquid pigment at the outlet of the droplet generating device to be between 6 μL / min and 10 μL / min, and the voltage applied by the high-voltage generator is between 10 kV and 20 kV. In this embodiment, through the above limitations, the size of the droplets during atomization can reach approximately several millimeters, and the particle size of the speckle particles formed after droplet atomization can reach 1 micrometer or less, thus realizing the preparation of tiny speckle particles.

[0013] In one possible implementation of the first aspect, the particle size of the speckle particles is between 0.5 μm and 1 μm.

[0014] In one possible implementation of the first aspect, the distance between the stage and the outlet of the droplet generating device is between 1 cm and 5 cm.

[0015] In one possible implementation of the first aspect, the outlet inner diameter of the droplet generating device is between 0.4 mm and 0.6 mm. Thus, the speckle particle preparation system is applicable to the preparation of small-sized test components or speckle particles in microfluidic fields at the millimeter or even micrometer scale. For example, the outlet inner diameter of the droplet generating device can be 0.4 mm, 0.5 mm, 0.6 mm, etc., and can be selected according to actual needs.

[0016] In one possible implementation of the first aspect, the color of the liquid pigment is different from the color of the sample to be tested. This avoids the situation where the color of the liquid pigment is the same as the color of the sample to be tested, making it impossible to identify the speckle particles formed by the atomization of the liquid pigment on the sample to be tested. It is achievable that the color of the liquid pigment and the color of the sample to be tested form a high contrast. For example, if the color of the sample to be tested is white, the color of the liquid pigment can be black or red to create a high contrast with white, avoiding situations where the color of the liquid pigment is too similar to the color of the sample to be accurately identified.

[0017] In a second aspect, a method for preparing speckle particles is provided, which utilizes the speckle particle preparation system of the first aspect or any possible implementation thereof. The method includes: placing a sample to be tested on a stage; connecting a liquid storage tank and a droplet generating device, wherein liquid pigment in the liquid storage tank gathers at the outlet of the droplet generating device to form droplets; activating a high-voltage generator, applying a voltage between the outlet of the droplet generating device and a conductive device to form a high-voltage electric field, wherein the droplets are atomized under the action of the high-voltage electric field, and the atomized droplets form speckle particles on the surface of the sample to be tested.

[0018] Based on the implementation methods provided in the above aspects, this application can be further combined to provide more implementation methods. Attached Figure Description

[0019] Figure 1 This is an exemplary structural schematic diagram of a speckle particle preparation system provided in an embodiment of this application;

[0020] Figure 2 This is an exemplary structural schematic diagram of another speckle particle preparation system provided in the embodiments of this application;

[0021] Figure 3 This is an exemplary flowchart of a speckle particle preparation method provided in an embodiment of this application. Detailed Implementation

[0022] The technical solutions in this application will now be described with reference to the accompanying drawings.

[0023] In the description of the embodiments of this application, unless otherwise stated, " / " means "or". For example, A / B can mean A or B. "And / or" in this document is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone.

[0024] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this embodiment, unless otherwise stated, "a plurality of" means two or more.

[0025] Speckle patterns are randomly distributed bright or dark spots that form unique patterns on the surface of a sample. These patterns change as the sample deforms or flows. By analyzing the changes in the speckle pattern on the sample surface before and after deformation or flow, the deformation, displacement, or flow velocity of the sample can be determined.

[0026] The most common method for preparing speckle patterns is manual spraying, where personnel use handheld spray paint or other speckle-making equipment to manually spray the surface of the sample. This method may result in uneven distribution of speckles on the sample surface, with some areas being dense and others sparse. This uneven distribution of speckles can lead to difficulties in uniformly tracking the deformation of the entire surface or the flow of the sample during subsequent analysis, thus affecting the accuracy and reliability of the measurement results.

[0027] In view of this, embodiments of this application provide a speckle particle preparation system, comprising: a storage tank for storing liquid pigment; a conductive droplet generating device, the inlet of which is connected to the outlet of the storage tank, the droplet generating device being used to gather the liquid pigment at the outlet of the droplet generating device to form droplets; a high-voltage generator and a conductive device, the first electrode of the high-voltage generator being connected to the droplet generating device, the second electrode of the high-voltage generator being connected to the conductive device, the high-voltage generator being used to apply voltage to form a high-voltage electric field between the droplet generating device and the conductive device, the droplets being atomized under the action of the high-voltage electric field; and a stage facing the outlet of the droplet generating device, the stage being used to carry the sample to be tested, the droplets being atomized to form speckle particles on the surface of the sample to be tested.

[0028] In this embodiment, liquid pigment is gathered into droplets at the outlet of the droplet generating device instead of being directly sprayed out. The droplet generating device is conductive and connected to the first pole of a high-voltage generator. When a voltage is applied, the high-voltage generator can form a high-voltage electric field between the outlet of the droplet generating device and the conductive device. Under the action of the high-voltage electric field, the droplets accumulate like charges. After the like charges in the droplets accumulate to a certain extent, the surface tension of the droplets will be unable to overcome the mutual repulsion electric field force between like charges, and the droplets will atomize and break up to form a fine spray, thereby forming uniformly distributed speckled particles on the surface of the sample to be tested.

[0029] like Figure 1 As shown, the speckle particle preparation system provided in this application includes a liquid storage tank 11, a conductive droplet generating device 12, a high-voltage generator (not shown in the figure), a conductive device 13, and a stage 14, on which the sample 30 to be tested is placed.

[0030] The storage tank 11 contains liquid pigment, the color of which differs from the color of the sample 30 to be tested. This avoids the situation where the liquid pigment's color is the same as the sample 30, making it impossible to identify the speckle particles formed by the atomization of the liquid pigment on the sample 30. It is possible to achieve a high contrast between the liquid pigment's color and the sample 30's color. For example, if the sample 30 is white, the liquid pigment could be black or red to create a high contrast with the white, avoiding situations where the liquid pigment's color is too similar to the sample 30 and cannot be accurately identified.

[0031] The inlet of the conductive droplet generating device 12 is connected to the outlet of the storage tank 11. The droplet generating device 12 is used to gather liquid pigment at the outlet of the droplet generating device 12 to form droplets 20. In one example, the conductive droplet generating device 12 can be a conductive needle. The inlet of the conductive needle is connected to the outlet of the storage tank 11 through a transmission channel. Liquid pigment flows out of the storage tank 11, flows into the inlet of the conductive needle, and gradually gathers at the outlet of the conductive needle to form droplets 20, instead of spraying the liquid pigment directly out. In another example, the conductive droplet generating device 12 includes a syringe 121 and a conductive needle 122. The inlet of the syringe 121 is connected to the outlet of the storage tank 11 via a transmission channel, and the outlet of the syringe 121 is connected to the inlet of the conductive needle 122. The inner diameter of the syringe 121 is larger than the inner diameter of the conductive needle 122. Liquid pigment flows out of the storage tank 11, into the inlet of the syringe 121, and then from the outlet of the syringe 121 into the inlet of the conductive needle 122, gradually accumulating at the outlet of the conductive needle 122 to form droplets 20. The syringe 121 is made of insulating material.

[0032] The first electrode of the high-voltage generator is connected to the droplet generating device 12, and the second electrode is connected to the conductive device 13. The high-voltage generator is used to apply voltage to form a high-voltage electric field between the droplet generating device 12 and the conductive device 13. Under the action of the high-voltage electric field, the droplets 20 are atomized to form a spray 40. The stage 14 is directly opposite the outlet of the droplet generating device 12 and is used to hold the sample 30 to be tested.

[0033] When a voltage is applied, the high-voltage generator can form a high-voltage electric field between the outlet of the droplet generating device 12 and the conductive device 13. Under the action of the high-voltage electric field, the droplet 20 accumulates like charges. After the like charges in the droplet 20 accumulate to a certain extent, the surface tension of the droplet 20 will be unable to overcome the mutual repulsion electric field force between like charges. The droplet 20 will be atomized and broken to form a fine spray 40, thereby forming a uniformly distributed speckled particle on the surface of the sample 30 to be tested.

[0034] in, Figure 1 As shown, the first electrode of the high-voltage generator is positive, and the second electrode is negative. The droplet generating device 12 is connected to the positive electrode, and the conductive device 13 is connected to the negative electrode. Under the influence of the high-voltage electric field, the droplet 20 accumulates positively charged like charges. In other examples, the first electrode of the high-voltage generator can be negative, and the second electrode can be positive. The droplet generating device 12 is connected to the negative electrode, and the conductive device 13 is connected to the positive electrode. Under the influence of the high-voltage electric field, the droplet 20 accumulates negatively charged like charges.

[0035] It is worth noting that the conductive device 13 is not connected to the conductive droplet generating device 12. The conductive device 13 can be a conductive tube or a conductive plate, etc. In this embodiment, there are no restrictions on the structural style of the conductive device 13, as long as it can conduct electricity. The conductive device 13 can be placed below the droplet generating device 12 or directly integrated on the stage 14.

[0036] Because the spray 40 formed after the droplets 20 atomize and break up has a relatively high and unstable initial speed, the speed of the spray 40 becomes more stable after a period of time. Furthermore, the spray 40 initially clumps together and is not sufficiently dispersed, causing the speckle particles formed on the surface of the sample 30 to easily overlap, affecting the accuracy of the measurement. However, in the stage where the speed is more stable, the spray 40 becomes more dispersed, and the speckle particles formed on the surface of the sample 30 are more evenly dispersed. Therefore, by measuring the first distance between the spray 40 and the outlet of the droplet generating device 12 when the speed is relatively stable, the stage 14 can be placed at a position 1 cm to 5 cm away from the outlet of the droplet generating device 12. For example, in this embodiment, the stage 14 can be placed at a position 1 cm to 5 cm away from the outlet of the droplet generating device 12.

[0037] Traditional spray painting methods for producing speckle particles suffer from insufficient material atomization and excessively large droplets. When used for preparing speckle particles for millimeter- or even micrometer-sized test components or microfluidic fields, only a few relatively large speckle particles can be formed, resulting in a limited number of particles and inaccurate measurement results. Therefore, traditional spray painting methods are not suitable for preparing speckle particles for millimeter- or even micrometer-sized test components or microfluidic fields. However, the speckle particle preparation system in this embodiment can form speckle particles of different sizes by adjusting the outlet inner diameter of the droplet generating device 12, making it suitable for preparing speckle particles for test samples 30 of different sizes.

[0038] For example, the outlet inner diameter of the droplet generating device 12 is between 0.4 mm and 0.6 mm. Thus, the speckle particle preparation system can be applied to the preparation of small-sized test components or speckle particles in microfluidic fields at the millimeter or even micrometer level. For example, the outlet inner diameter of the droplet generating device 12 can be 0.4 mm, 0.5 mm, 0.6 mm, etc., and can be selected according to actual needs.

[0039] like Figure 2As shown, this application embodiment also provides another speckle particle preparation system, which includes not only the liquid storage tank 11, the conductive droplet generating device 12, the high-pressure generator (not shown in the figure), the conductive device 13, and the stage 14 in the above embodiment, but also an injection pump 15 connected between the outlet of the liquid storage tank 11 and the inlet of the droplet generating device 12.

[0040] The injection pump 15 is used to control the droplet aggregation speed of the liquid pigment at the outlet of the droplet generating device 12. By controlling the droplet aggregation speed of the liquid pigment at the outlet of the droplet generating device 12 and the voltage of the high-voltage electric field, the size of the droplet 20 during atomization can be controlled, thereby controlling the size of the speckle particles formed after atomization, and enabling the preparation of speckle particles with controllable size and uniform distribution.

[0041] In one example, the conductive droplet generating device 12 can be a conductive needle. The inlet of the syringe pump 15 is connected to the outlet of the reservoir 11, and the inlet of the syringe pump 15 is connected to the inlet of the conductive needle. Liquid pigment flows out from the reservoir 11, and the syringe pump 15 controls the liquid pigment to flow into the inlet of the conductive needle at a certain flow rate, gradually accumulating at the outlet of the conductive needle to form droplets 20. In another example, the conductive droplet generating device 12 includes a syringe 121 and a conductive needle 122. The inlet of the syringe pump 15 is connected to the outlet of the reservoir 11, and the inlet of the syringe pump 15 is connected to the inlet of the syringe 121. The outlet of the syringe 121 is connected to the inlet of the conductive needle 122, and the inner diameter of the syringe 121 is larger than the inner diameter of the conductive needle 122. Liquid pigment flows out from the storage tank 11. The injection pump 15 controls the liquid pigment to flow into the inlet of the syringe 121 at a certain flow rate, and then flows from the outlet of the syringe 121 into the inlet of the conductive needle 122, where it gradually gathers to form droplets 20 at the outlet of the conductive needle 122.

[0042] For example, the outlet inner diameter of the droplet generating device 12 is between 0.4 mm and 0.6 mm. Thus, the speckle particle preparation system can be applied to the preparation of small-sized test components or speckle particles in microfluidic fields at the millimeter or even micrometer level. For example, the outlet inner diameter of the droplet generating device 12 can be 0.4 mm, 0.5 mm, 0.6 mm, etc., and can be selected according to actual needs.

[0043] For example, the injection pump 15 controls the droplet aggregation rate of the liquid pigment at the outlet of the droplet generating device 12 to be between 5 μL / min and 25 μL / min, and the voltage applied by the high-voltage generator is between 5 kV and 25 kV. At this time, the size of the atomized droplets 20 can reach approximately several millimeters, and the particle size of the speckled particles formed after atomization can reach several micrometers or even a fraction of a micrometer, realizing the preparation of tiny speckled particles. The particle size of the speckled particles can be between 0.5 μm and 3 μm. The droplet aggregation rate can be 5 μL / min, 6 μL / min, 10 μL / min, 15 μL / min, 25 μL / min, etc.; the voltage applied by the high-voltage generator can be 5 kV, 10 kV, 20 kV, 25 kV, etc., and can be selected according to actual needs.

[0044] With a fixed outlet inner diameter of the droplet generating device 12, the injection pump 15 controls the droplet aggregation rate of the liquid pigment at the outlet of the droplet generating device 12 to be between 5 μL / min and 25 μL / min, and the voltage applied by the high-voltage generator is between 5 kV and 25 kV. The time from the extrusion of the droplet 20 to its breakup and atomization is approximately 2 ms to 5 ms. The initial velocity of the spray 40 formed after atomization is approximately between 2 m / s and 4.5 m / s, and the stable velocity is approximately between 1.50 m / s and 2 m / s. The time from atomization to the stabilization of the velocity is approximately 2 ms to 10 ms. At this time, when the velocity of the spray 40 is relatively stable, the first distance between it and the outlet of the droplet generating device 12 is between 1 cm and 5 cm. Therefore, the stage 14 can be placed at a position 1 cm to 5 cm away from the outlet of the droplet generating device 12.

[0045] In one possible implementation, the injection pump 15 controls the droplet aggregation rate of the liquid pigment at the outlet of the droplet generating device 12 to be between 6 μL / min and 10 μL / min, and the voltage applied by the high-voltage generator is between 10 kV and 20 kV. In this case, the particle size of the speckle particles formed after the droplets 20 are atomized can reach 1 micrometer or less, specifically, the particle size of the speckle particles is between 0.5 μm and 1 μm. The droplet aggregation rate can be 6 μL / min, 8 μL / min, 10 μL / min, 15 μL / min, 25 μL / min, etc.; the voltage applied by the high-voltage generator can be 10 kV, 12 kV, 15 kV, 20 kV, etc., and can be selected according to actual needs.

[0046] With a fixed outlet inner diameter of the droplet generating device 12, the injection pump 15 controls the droplet aggregation rate of the liquid pigment at the outlet of the droplet generating device 12 to be between 6 μL / min and 10 μL / min, and the voltage applied by the high-voltage generator is between 10 kV and 20 kV. The time from the extrusion of the droplet 20 to its breakup and atomization is approximately 2 ms. The initial velocity of the spray 40 formed after atomization is approximately between 2.5 m / s and 3 m / s, and the stable velocity is approximately 1.50 m / s. The time from atomization to the stabilization of the velocity is approximately 3 ms to 5 ms. At this time, the initial distance between the spray 40 and the outlet of the droplet generating device 12 when the velocity is relatively stable is between 1 cm and 5 cm. Therefore, the stage 14 can be placed at a position 1.5 cm to 2.0 cm away from the outlet of the droplet generating device 12.

[0047] In summary, in this embodiment, liquid pigment is gathered at the outlet of droplet generating device 12 to form droplets 20, instead of being directly sprayed out. Droplet generating device 12 is conductive and connected to the first pole of a high-voltage generator. When voltage is applied, the high-voltage generator can form a high-voltage electric field between the outlet of droplet generating device 12 and the conductive device 13. Under the action of the high-voltage electric field, droplets 20 accumulate like charges. After the like charges in droplets 20 accumulate to a certain extent, the surface tension of droplets 20 will be unable to overcome the mutual repulsion electric field force between like charges, and droplets 20 will atomize and break up to form a fine spray 40, thereby forming uniformly distributed speckled particles on the surface of the sample 30 to be tested. By controlling the droplet gathering speed of liquid pigment at the outlet of droplet generating device 12 and the voltage of the high-voltage electric field, the size of droplets 20 during atomization can be controlled, thereby controlling the size of speckled particles formed after atomization, and thus achieving the preparation of speckled particles with controllable size and uniform distribution.

[0048] It is worth noting that by adjusting the voltage of the high-voltage electric field, the size of the liquid storage tank 11, the outlet size of the droplet generating device 12, and the driving parameters of the injection pump 15, the device proposed in this embodiment can also be used to produce speckle particles on the surface of other larger-sized devices, and the quality of the speckle particles can also be well guaranteed.

[0049] Furthermore, the device proposed in this embodiment can also be used in various scenarios that require the use of droplet 20 atomization spraying, such as the distribution of tracer particles in the process of particle image velocimetry method for measuring the velocity of the flow field in a small-sized flow channel in the field of fluid mechanics, where the atomized micro-droplets 20 generated by the device proposed in this embodiment can be used as tracer particles, etc.

[0050] In summary, this application addresses the problems of poor stability and difficulty in quantitatively controlling the speckle particle preparation process in existing methods. Utilizing the concept of charge enrichment, the surface of droplet 20 accumulates like charges due to the connection of electrodes. Once this enrichment reaches a certain level, the surface tension of droplet 20 breaks up and atomizes because it cannot overcome the repulsive electric field between the charges. By effectively controlling electrical parameters such as electrode voltage and accurately controlling the pumping speed and flow rate of droplet 20 via injection pump 15, the extrusion speed, extrusion rate, and surface charge enrichment rate of droplet 20 can be quantitatively controlled. This ultimately achieves accurate control over the diameter of droplet 20 before and after atomization, and the movement speed of the spray 40 after atomization. The atomized droplets 20 eventually reach the surface of the sample 30 to be measured, forming uniformly distributed speckle particles.

[0051] Secondly, the embodiments of this application overcome the problem that existing speckle particle preparation methods are difficult to adapt to the small size of the test sample 30. The droplets 20 are extruded through a micro-inflation needle, and the particle size before and after atomization is controllable. The atomization process, which involves near-spherical bursting, effectively covers the surface of the test sample 30. By simply aligning the micro-inflation needle with the area of ​​the test sample 30 where the displacement / strain needs to be measured, the droplets 20 are controlled to accumulate charge and break up and atomize, thereby realizing the preparation of speckle particles.

[0052] Finally, based on the testing principle of Digital Image Correlation (DIC) technology, the establishment of the image background color is not actually necessary in the process of creating speckle particles. The technology proposed in the embodiments of this application can be used to atomize liquid pigments with a strong color contrast to the surface color of the sample 30 to be tested. The resulting speckle particles form a strong color contrast with the surface of the sample 30 to be tested. In this way, the accuracy of the displacement, strain or flow velocity measurement of the sample 30 to be tested can be guaranteed when using the digital image correlation algorithm in subsequent calculations.

[0053] It should be understood that the above examples are provided to help those skilled in the art understand the embodiments of this application, and are not intended to limit the embodiments of this application to the specific values ​​or scenarios illustrated. Those skilled in the art can obviously make various equivalent modifications or changes based on the above examples, and such modifications or changes also fall within the scope of the embodiments of this application.

[0054] Secondly, a method for preparing speckle particles is provided, which utilizes the speckle particle preparation system in any of the above embodiments.

[0055] like Figure 3 As shown, the method for preparing speckle particles includes the following steps.

[0056] Step S101: Place the sample to be tested on the stage.

[0057] In step S102, the liquid storage tank and the droplet generating device are connected, and the liquid pigment in the liquid storage tank gathers at the outlet of the droplet generating device to form droplets.

[0058] Step S103: Start the high voltage generator and apply a voltage between the outlet of the droplet generating device and the conductive device to form a high voltage electric field. The droplets are atomized under the action of the high voltage electric field, and after atomization, speckle particles are formed on the surface of the sample to be tested.

[0059] In this embodiment, liquid pigment is gathered into droplets at the outlet of the droplet generating device instead of being directly sprayed out. The droplet generating device is conductive and connected to the first pole of the high-voltage generator. When a voltage is applied, the high-voltage generator can form a high-voltage electric field between the outlet of the droplet generating device and the conductive device. Under the action of the high-voltage electric field, the droplets accumulate like charges. After the like charges in the droplets accumulate to a certain extent, the surface tension of the droplets will be unable to overcome the repulsive electric field force between like charges, and the droplets will atomize and break up to form a fine spray, thereby forming uniformly distributed speckled particles on the surface of the sample to be tested.

[0060] In the case where the speckle particle preparation system also includes an injection pump connected between the outlet of the storage tank and the inlet of the droplet generating device, the above step S102 specifically involves: starting the injection pump, and the liquid pigment in the storage tank aggregating at the outlet of the droplet generating device to form droplets.

[0061] In this embodiment, by controlling the droplet aggregation speed of the liquid pigment at the outlet of the droplet generating device and the voltage of the high-voltage electric field, the size of the droplets during atomization can be controlled, thereby controlling the size of the speckled particles formed after atomization, and thus enabling the preparation of speckled particles with controllable size and uniform distribution.

[0062] It is worth noting that the speckle particle preparation method in this application embodiment can be prepared using the parameters of the speckle particle preparation system in the above embodiment. For details, please refer to the description in the above embodiment, which will not be repeated here.

[0063] The following example, using sample 30 as an internal component of a small electronic device (e.g., an internal spring sheet of a linear motor), illustrates how the speckle particle preparation system in the above embodiment can prepare small and uniformly dispersed speckle particles when the internal component of the electronic device is small (millimeter level) and the preparation window is small.

[0064] To solve the above-mentioned technical problems, this embodiment uses the method of enriching the surface of droplets 20 with the same charge, so that the droplets 20 are broken and atomized and then received by the sample to be tested 30, instead of the traditional spraying method to create speckle patterns.

[0065] See Figure 2 As shown, the storage tank 11 contains liquid pigment for speckle formation. The injection pump 15 is connected to the storage tank 11 via a hose. The injection pump 15 is a precision peristaltic pump, consisting of a driver, a pump head, and a hose. This pump works by using peristaltic motion to draw in and expel the liquid pigment. Its core component is an elastic tube; when external pressure is applied to the tube, it contracts and expands, thus conveying the liquid pigment. The pump head rotation speed can be controlled by the driver to achieve equal pumping volume of liquid pigment while controlling the pumping speed, thereby controlling the single extrusion volume and frequency of liquid pigment atomization.

[0066] The outlet of the syringe pump 15 is connected to the inlet of the droplet generating device 12 via a flexible tube. The droplet generating device 12 may include a conductive needle 122 and a syringe 121. The syringe 121 may be a micro-injector, and the conductive needle 122 may be made of metal. The positive (or negative) terminal of the high-voltage generator is connected to the conductive needle 122, and the conductive device 13 is connected to the negative (or positive) terminal of the high-voltage electric field. A high-voltage electric field will be formed between the conductive needle 122 and the conductive device 13 when the high-voltage electric field is energized.

[0067] The droplets 20 squeezed out by the precision peristaltic pump will accumulate like charges under the action of a high voltage electric field. After the charge accumulates to a certain extent, the surface tension of the droplets 20 will be unable to overcome the mutual repulsion electric field force between like charges, and the droplets 20 will atomize and break up to form a fine spray 40.

[0068] The stage 14 is placed on the movement path of the spray 40, and small electronic components are placed on the stage 14. After multiple sprays 40, speckle particles can be produced.

[0069] The specific preparation method is as follows: turn on the driver of the precision peristaltic pump, control the start of the precision peristaltic pump, and adjust the speed of the peristaltic pump to achieve a pumping speed of 6-10 μL / min for droplet 20. A high-voltage electric field of 10-20kV is applied between the conductive needle 122 and the conductive device 13 of the micro-injector 121 to enrich the droplets 20 extruded by the peristaltic pump with the same charge. The time from the extrusion of the droplets 20 to the completion of charge enrichment and before atomization is about 2ms. For the speckle pattern production process, it can be considered as continuous atomization spraying. The initial velocity of the atomized droplets 20 is 2.5m / s to 3.0m / s, and the stable velocity is about 1.5m / s. The time from atomization to the stabilization of the velocity is about 3ms to 5ms, which is about 1.5cm to 2.0cm from the tip of the conductive needle 122. The atomized droplets 20 can have a relatively stable velocity, which facilitates the alignment between the conductive needle 122 and the sample 30 to be tested. The particle size of the atomized droplets 20 is 0.5μm to 1μm.

[0070] By moving the slide or manually adjusting the relative position between the sample 30 and the conductive needle 122, the sample 30 can be aligned with the conductive needle 122 to complete the speckle pattern fabrication, obtaining speckles with appropriate particle size, uniform speckle distribution, and strong contrast with the background. The final speckle image quality should be such that, after algorithmic calculation using Digital Image Correlation (DIC) technology, the calculation error of deformation displacement can be controlled to be below approximately 0.1 pixels.

[0071] Afterwards, turn off the peristaltic pump, disconnect the high-voltage electric field power supply, and empty the remaining liquid in the storage tank 11.

[0072] It should be understood that the above examples are provided to help those skilled in the art understand the embodiments of this application, and are not intended to limit the embodiments of this application to the specific values ​​or scenarios illustrated. Those skilled in the art can obviously make various equivalent modifications or changes based on the above examples, and such modifications or changes also fall within the scope of the embodiments of this application.

[0073] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of the embodiments of this application.

[0074] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, units, and processes described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0075] In the embodiments provided in this application, it should be understood that the disclosed systems, methods, and approaches can be implemented in other ways. For example, the system embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual couplings, direct couplings, or communication connections may be through some interfaces; indirect couplings or communication connections between systems or units may be electrical, mechanical, or other forms.

[0076] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0077] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0078] If the aforementioned function is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application embodiment, essentially, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a memory (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0079] The above description is merely a specific implementation of the embodiments of this application, but the protection scope of the embodiments of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the embodiments of this application should be included within the protection scope of the embodiments of this application. Therefore, the protection scope of the embodiments of this application should be determined by the protection scope of the claims.

Claims

1. A speckle particle preparation system, characterized in that, The system includes: Storage tanks are used to store liquid pigments; A conductive droplet generating device, wherein the inlet of the droplet generating device is connected to the outlet of the liquid storage tank, and the droplet generating device is used to gather the liquid pigment at the outlet of the droplet generating device to form droplets; A high-voltage generator and a conductive device are provided. The first electrode of the high-voltage generator is connected to the droplet generating device, and the second electrode of the high-voltage generator is connected to the conductive device. The high-voltage generator is used to apply voltage to form a high-voltage electric field between the droplet generating device and the conductive device, and the droplets are atomized under the action of the high-voltage electric field. A stage facing the outlet of the droplet generating device is used to hold the sample to be tested, and the droplets are atomized to form speckle particles on the surface of the sample to be tested.

2. The system according to claim 1, characterized in that, The system further includes an injection pump connected between the outlet of the liquid storage tank and the inlet of the droplet generating device, the injection pump being used to control the droplet aggregation rate of the liquid pigment at the outlet of the droplet generating device.

3. The system according to claim 2, characterized in that, The droplet generating device includes a syringe and a conductive needle. The inlet of the syringe is connected to the outlet of the injection pump, and the outlet of the syringe is connected to the inlet of the conductive needle. The syringe and the conductive needle are used to gather the liquid pigment at the outlet of the conductive needle to form droplets.

4. The system according to claim 2 or 3, characterized in that, The injection pump controls the liquid pigment to accumulate at a rate between 5 μL / min and 25 μL / min at the outlet of the droplet generating device, and the voltage applied by the high-voltage generator is between 5 kV and 25 kV.

5. The system according to claim 4, characterized in that, The particle size of the speckled particles is between 0.5 μm and 3 μm.

6. The system according to claim 4, characterized in that, The injection pump controls the liquid pigment to accumulate at a rate between 6 μL / min and 10 μL / min at the outlet of the droplet generating device, and the voltage applied by the high-voltage generator is between 10 kV and 20 kV.

7. The system according to claim 6, characterized in that, The particle size of the speckled particles is between 0.5 μm and 1 μm.

8. The system according to any one of claims 2 to 7, characterized in that, The distance between the stage and the outlet of the droplet generating device is between 1 cm and 5 cm.

9. The system according to any one of claims 1 to 8, characterized in that, The outlet inner diameter of the droplet generating device is between 0.4 mm and 0.6 mm.

10. The system according to any one of claims 1 to 9, characterized in that, The color of the liquid pigment is different from the color of the sample to be tested.

11. A method for preparing speckle particles, characterized in that, The method comprises preparing the speckle particles using the speckle particle preparation system according to any one of claims 1-10, wherein the preparation method includes: Place the sample to be tested on the stage; A liquid storage tank and a droplet generating device are connected, and the liquid pigment in the liquid storage tank gathers at the outlet of the droplet generating device to form droplets; The high-voltage generator is activated, and a voltage is applied between the outlet of the droplet generating device and the conductive device to form a high-voltage electric field. The droplets are atomized under the action of the high-voltage electric field, and after atomization, the droplets form speckle particles on the surface of the sample to be tested.

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